The effect of DPP-4 inhibitors on asthma control: an administrative database study to evaluate a potential pathophysiological relationship.

PubMed

Colice, Gene; Price, David; Gerhardsson de Verdier, Maria; Rabon-Stith, Karma; Ambrose, Christopher; Cappell, Katherine; Irwin, Debra E; Juneau, Paul; Vlahiotis, Anna

2017-01-01

DPP-4 may regulate immunological pathways implicated in asthma. Assessing whether DPP-4 inhibitor (DPP-4i) use might affect asthma control is clinically important because DPP-4i use in type 2 diabetes mellitus management (T2DM) is increasing. This study evaluated associations between DPP-4i use and asthma control. This was a retrospective, observational, matched cohort study using administrative claims in the MarketScan ® Commercial Claims and Encounters (Commercial) and Medicare Supplemental and Coordination of Benefits (Medicare Supplemental) databases. Adult asthma patients initiating an oral DPP-4i or a non-DPP-4i between November 1, 2006 and March 31, 2014 were included. Patients were followed for asthma-related outcomes for 12 months after initiation of the antidiabetes medication. Outcomes included risk-domain asthma control (RDAC), defined as no asthma hospitalizations, no lower respiratory tract infections, and no oral corticosteroid (OCS) prescriptions; overall asthma control (RDAC criteria plus limited short-acting beta agonist use); treatment stability (RDAC criteria plus no increase of ≥50% in inhaled corticosteroid dose or addition of other asthma therapy); and severe asthma exacerbation rates (asthma-related hospitalizations, emergency room visits, or acute treatments with OCS). Comparisons were made between two matched cohorts (DPP-4i vs. non-DPP-4i initiators) using multivariable logistic regression and generalized linear modeling. Covariates included baseline demographic and clinical characteristics related to asthma and T2DM. The adjusted odds of achieving RDAC (odds ratio [OR]: 1.05; 95% CI: 0.964 to 1.147), overall asthma control (OR: 1.04; 95% CI: 0.956 to 1.135), and treatment stability (OR: 1.04; 95% CI: 0.949 to 1.115) did not differ between the DPP-4i and non-DPP-4i cohorts. A difference was not found between cohorts in severe asthma exacerbation rates during the 12 months following initiation of antidiabetes treatment (mean = 0.32 vs. 0.34 exacerbations per subject-year, respectively; p =0.064). Asthma control was similar between patients initiating DPP-4i and non-DPP-4i antidiabetes medications, suggesting no association between DPP-4i use and asthma control.

Recent progress of the development of dipeptidyl peptidase-4 inhibitors for the treatment of type 2 diabetes mellitus.

PubMed

Li, Ning; Wang, Li-Jun; Jiang, Bo; Li, Xiang-Qian; Guo, Chuan-Long; Guo, Shu-Ju; Shi, Da-Yong

2018-05-10

Diabetes is a fast growing chronic metabolic disorder around the world. Dipeptidyl peptidase-4 (DPP-4) is a new promising target during type 2 diabetes glycemic control. Thus, a number of potent DPP-4 inhibitors were developed and play a rapidly evolving role in the management of type 2 diabetes in recent years. This article reviews the development of synthetic and natural DPP-4 inhibitors from 2012 to 2017 and provides their physico-chemical properties, biological activities against DPP-4 and selectivity over dipeptidyl peptidase-8/9. Moreover, the glucose-lowering mechanisms and the active site of DPP-4 are also discussed. We also discuss strategies and structure-activity relationships for identifying potent DPP-4 inhibitors, which will provide useful information for developing potent DPP-4 drugs as type 2 diabtes treatments. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Substituted 4-carboxymethylpyroglutamic acid diamides as potent and selective inhibitors of fibroblast activation protein.

PubMed

Tsai, Ting-Yueh; Yeh, Teng-Kuang; Chen, Xin; Hsu, Tsu; Jao, Yu-Chen; Huang, Chih-Hsiang; Song, Jen-Shin; Huang, Yu-Chen; Chien, Chia-Hui; Chiu, Jing-Huai; Yen, Shih-Chieh; Tang, Hung-Kuan; Chao, Yu-Sheng; Jiaang, Weir-Torn

2010-09-23

Fibroblast activation protein (FAP) belongs to the prolyl peptidase family. FAP inhibition is expected to become a new antitumor target. Most known FAP inhibitors often resemble the dipeptide cleavage products, with a boroproline at the P1 site; however, these inhibitors also inhibit DPP-IV, DPP-II, DPP8, and DPP9. Potent and selective FAP inhibitor is needed in evaluating that FAP as a therapeutic target. Therefore, it is important to develop selective FAP inhibitors for the use of target validation. To achieve this, optimization of the nonselective DPP-IV inhibitor 8 led to the discovery of a new class of substituted 4-carboxymethylpyroglutamic acid diamides as FAP inhibitors. SAR studies resulted in a number of FAP inhibitors having IC(50) of <100 nM with excellent selectivity over DPP-IV, DPP-II, DPP8, and DPP9 (IC(50) > 100 μM). Compounds 18a, 18b, and 19 are the only known potent and selective FAP inhibitors, which prompts us to further study the physiological role of FAP.

SGLT2 inhibitor/DPP-4 inhibitor combination therapy - complementary mechanisms of action for management of type 2 diabetes mellitus.

PubMed

Dey, Jayant

2017-05-01

Type 2 diabetes mellitus is a progressive disease with multiple underlying pathophysiologic defects. Monotherapy alone cannot maintain glycemic control and leads to treatment failure. Ideally, a combination of glucose-lowering agents should have complementary mechanisms of action that address multiple pathophysiologic pathways, can be used at all stages of the disease, and be generally well tolerated with no increased risk of hypoglycemia, cardiovascular events, or weight gain. The combination should also provide conveniences for patients, such as oral dosing, single-pill formulations, and once-daily administration, potentially translating to improved adherence. Two classes of glucose-lowering agents that meet these criteria are the sodium glucose cotransporter-2 (SGLT2) inhibitors and dipeptidyl peptidase-4 (DPP-4) inhibitors. This article reviews the rationale for combination therapy with these agents, and evidence from clinical trials with empagliflozin and linagliptin or dapagliflozin and saxagliptin in the management of type 2 diabetes mellitus. Both combinations have been approved as single-pill formulations.

The Place of Dipeptidyl Peptidase-4 Inhibitors in Type 2 Diabetes Therapeutics: A “Me Too” or “the Special One” Antidiabetic Class?

PubMed Central

Godinho, Ricardo; Carvalho, Eugénia; Teixeira, Frederico

2015-01-01

Incretin-based therapies, the most recent therapeutic options for type 2 diabetes mellitus (T2DM) management, can modify various elements of the disease, including hypersecretion of glucagon, abnormal gastric emptying, postprandial hyperglycaemia, and, possibly, pancreatic β cell dysfunction. Dipeptidyl peptidase-4 (DPP-4) inhibitors (gliptins) increase glucagon-like peptide-1 (GLP-1) availability and correct the “incretin defect” seen in T2DM patients. Clinical studies have shown good glycaemic control with minimal risk of hypoglycaemia or any other adverse effects, despite the reports of pancreatitis, whose association remains to be proved. Recent studies have been focusing on the putative ability of DPP-4 inhibitors to preserve pancreas function, in particular due to the inhibition of apoptotic pathways and stimulation of β cell proliferation. In addition, other cytoprotective effects on other organs/tissues that are involved in serious T2DM complications, including the heart, kidney, and retina, have been increasingly reported. This review outlines the therapeutic potential of DPP-4 inhibitors for the treatment of T2DM, focusing on their main features, clinical applications, and risks, and discusses the major challenges for the future, in particular the possibility of becoming the preferred therapy for T2DM due to their ability to modify the natural history of the disease and ameliorate nephropathy, retinopathy, and cardiovascular complications. PMID:26075286

Wound healing effects of dipeptidyl peptidase-4 inhibitors: An emerging concept in management of diabetic foot ulcer-A review.

PubMed

Saboo, Apoorva; Rathnayake, Ayeshmanthe; Vangaveti, Venkat N; Malabu, Usman H

2016-01-01

Dipeptidyl peptidase-4 (DPP-4) inhibitors have a well-known effect on glycaemic control in patients with diabetes but little is known on their wound healing role in this group of population. This paper reviews the effects of DPP-4 inhibitors on wound healing of diabetic foot ulcers. Published data on effects and mechanism of DDP-4 inhibitors on wound healing were derived from Medline, PubMed and Google Scholar search of English language literature from 1994 to 2014 using the key words such as "DPP-4 inhibitors", "endothelial healing" "diabetes" and "chronic ulcers". DPP-4 inhibitors show a potential benefit in processes of wound healing in diabetic chronic foot ulcers. The enzyme inhibitors promote recruitment of endothelial progenitor cells and allow the final scaffolding of wounds. Furthermore DPP-4 inhibitors augment angiogenesis and have widespread effects on optimising the immune response to persistent hypoxia in chronic diabetes wounds. DPP-4 inhibitors show promise in the local wound healing of diabetic foot ulcers in addition to its already established glycaemic control. In the light of high rate of amputations due to non-healing ulcers with profound psychological and economical liability, more investigations on the usefulness of DPP-4 inhibitors in the high risk diabetes population are needed. Copyright © 2015 Diabetes India. Published by Elsevier Ltd. All rights reserved.

Effectiveness and Safety of Newer Antidiabetic Medications for Ramadan Fasting Diabetic Patients

PubMed Central

2016-01-01

Hypoglycemia is the most common side effects for most glucose-lowering therapies. It constitutes a serious risk that faces diabetic patients who fast during Ramadan (the 9th month in the Islamic calendar). New glucose-lowering classes like dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide 1 receptor agonist (GLP-1 RA), and sodium-glucose cotransporter-2 (SGLT-2) inhibitors are efficacious in controlling blood glucose level with less tendency to induce hypoglycemia and thus may constitute a good choice for diabetic patients during Ramadan. This study reviews the safety and efficacy of newer glucose-lowering therapies during Ramadan. This study was accomplished through a careful literature search about studies that assess the benefit and side effects of these new glucose-lowering therapies during Ramadan during September 2015. Vildagliptin, sitagliptin, liraglutide, exenatide, and dapagliflozin were the only studied glucose-lowering therapies. All of the studied newer glucose-lowering therapies except dapagliflozin were associated with reduced risk to induce hypoglycemia. Gastrointestinal upset was common with the usage of liraglutide while increased thirst sensation was common with dapagliflozin. In conclusion DPP-4 inhibitors such as vildagliptin and sitagliptin may form a suitable glucose-lowering therapy option for Ramadan fasting patients. PMID:27642611

The Vildagliptin Experience - 25 Years Since the Initiation of the Novartis Glucagon-like Peptide-1 Based Therapy Programme and 10 Years Since the First Vildagliptin Registration.

PubMed

Foley, James E; Ahrén, Bo

2017-08-01

The discovery of the incretin hormone glucagon like peptide-1 (GLP-1), and its usefulness in the treatment of type 2 diabetes mellitus (T2DM) followed by the finding that dipeptidyl peptidase-4 (DPP-4) inhibition prevents GLP-1 inactivation, led to the discovery of DPP-728. In 1999, studies with DPP-728 established the first proof-of-concept that DPP-4 inhibition improves glycaemic control in patients with T2DM. Further efforts to improve the binding kinetics of DPP-728 resulted in the discovery of vildagliptin (LAF237). In the last 20 years, a plethora of studies conducted by Novartis in collaboration with external investigators has demonstrated the mechanism of action of vildagliptin and its efficacy as monotherapy and as an add-on therapy for patients with T2DM. The studies establish that vildagliptin is a selective DPP-4 inhibitor that blocks GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) inactivation, thereby prolonging their action, resulting in improved glycaemic control. This review aims to discuss the discovery and development of vildagliptin, with an emphasis on mechanism of action and clinical efficacy.

Choosing between GLP-1 Receptor Agonists and DPP-4 Inhibitors: A Pharmacological Perspective

PubMed Central

Brown, Dominique Xavier; Evans, Marc

2012-01-01

In recent years the incretin therapies have provided a new treatment option for patients with type 2 diabetes mellitus (T2DM). The incretin therapies focus on the increasing levels of the two incretin hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). This results in increased glucose dependent insulin synthesis and release. GLP-1 receptor agonists such as liraglutide and exenatide exert an intrinsic biological effect on GLP-1 receptors directly stimulating the release of insulin from pancreatic beta cells. DPP-4 inhibitors such as sitagliptin and linagliptin prevent the inactivation of endogenous GLP-1 and GIP through competitive inhibition of the DPP-4 enzyme. Both incretin therapies have good safety and tolerability profiles and interact minimally with a number of medications commonly prescribed in T2DM. This paper focuses on the pharmacological basis by which the incretin therapies function and how this knowledge can inform and benefit clinical decisions. Each individual incretin agent has benefits and pitfalls relating to aspects such as glycaemic and nonglycaemic efficacy, safety and tolerability, ease of administration, and cost. Overall, a personalized medicine approach has been found to be favourable, tailoring the incretin agent to benefit and suit patient's needs such as renal impairment (RI) or hepatic impairment (HI). PMID:23125920

Omarigliptin (MK-3102): A Novel Long-Acting DPP-4 Inhibitor for Once-Weekly Treatment of Type 2 Diabetes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biftu, Tesfaye; Sinha-Roy, Ranabir; Chen, Ping

In our effort to discover DPP-4 inhibitors with added benefits over currently commercially available DPP-4 inhibitors, MK-3102 (omarigliptin), was identified as a potent and selective dipeptidyl peptidase 4 (DPP-4) inhibitor with an excellent pharmacokinetic profile amenable for once-weekly human dosing and selected as a clinical development candidate. This manuscript summarizes the mechanism of action, scientific rationale, medicinal chemistry, pharmacokinetic properties, and human efficacy data for omarigliptin, which is currently in phase 3 clinical development.

Structural Biology and Molecular Modeling in the Design of Novel DPP-4 Inhibitors

NASA Astrophysics Data System (ADS)

Scapin, Giovanna

Inhibition of dipeptidyl peptidase IV (DPP-4) is a promising new approach for the treatment of type 2 diabetes. DPP-4 is the enzyme responsible for inactivating the incretin hormones glucagon-like peptide 1 (GLP-1) and glucose dependent insulinotropic polypeptide (GIP), two hormones that play important roles in glucose homeostasis. The potent, orally bioavailable and highly selective small molecule DPP-4 inhibitor sitagliptin has been approved by the FDA as novel drug for the treatment of type 2 diabetes. The comparison between the binding mode of sitagliptin (a β-amino acid) and that of a second class of inhibitors (α-amino acid-based) initially led to the successful identification and design of structurally diverse and highly potent DPP-4 inhibitors. Further analysis of the crystal structure of sitagliptin bound to DPP-4 suggested that the central β-amino butanoyl moiety could be replaced by a rigid group. This was confirmed by molecular modeling, and the resulting cyclohexylamine analogs were synthesized and found to be potent DPP-4 inhibitors. However, the triazolopyrazine was predicted to be distorted in order to fit in the binding pocket, and the crystal structure showed that multiple conformations exist for this moiety. Additional molecular modeling studies were then used to improve potency of the cyclohexylamine series. In addition, a 3-D QSAR method was used to gain insight for reducing off-target DPP-8/9 activities. Novel compounds were thus synthesized and found to be potent DPP-4 inhibitors. Two compounds in particular were designed to be highly selective against off-target "DPP-4 Activity- and/or Structure Homologues" (DASH) enzymes while maintaining potency against DPP-4.

[Research progress of dipeptidyl peptidase 4 inhibitors on healing of chronic diabetic foot ulcers].

PubMed

Gao, Yunyi; Liang, Yujie; Ran, Xingwu

2018-05-01

To review the effect of dipeptidyl peptidase 4 (DPP-4) inhibitors on the wound healing and its mechanisms in chronic diabetic foot ulcers. The latest literature concerning DPP-4 inhibitors for chronic diabetic foot ulcers was extensively reviewed, as well as the potential benefit and mechanism of DPP-4 inhibitors on wound healing of diabetic foot ulcers was analyzed thoroughly. DPP-4 inhibitors can accelerated the ulcer healing. The mechanisms probably include inhibiting the expression of the matrix metalloproteinase (MMP) and restoring the balance of the wound MMP and the tissue inhibitors of MMP; promoting recruitment of endothelial progenitor cells and augmenting angiogenesis; optimizing extracellular matrix construction and the immune response to persistent hypoxia in chronic diabetes wounds, and so on. At present, clinical researches show that DPP-4 inhibitors may be considered as an adjuvant treatment for chronic diabetic foot ulcers. DPP-4 inhibitors show promise in the local wound healing of chronic diabetic foot ulcers. However, more strictly designed, adequately powered, long-term follow-up, and high-quality randomized control trials are needed to further verify their efficacy and safety for chronic diabetic foot ulcers.

Discovery of Novel Tricyclic Heterocycles as Potent and Selective DPP-4 Inhibitors for the Treatment of Type 2 Diabetes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Wen-Lian; Hao, Jinsong; Domalski, Martin

In our efforts to develop second generation DPP-4 inhibitors, we endeavored to identify distinct structures with long-acting (once weekly) potential. Taking advantage of X-ray cocrystal structures of sitagliptin and other DPP-4 inhibitors, such as alogliptin and linagliptin bound to DPP-4, and aided by molecular modeling, we designed several series of heterocyclic compounds as initial targets. During their synthesis, an unexpected chemical transformation provided a novel tricyclic scaffold that was beyond our original design. Capitalizing on this serendipitous discovery, we have elaborated this scaffold into a very potent and selective DPP-4 inhibitor lead series, as highlighted by compound 17c.

Efficacy and safety of once-weekly oral trelagliptin switched from once-daily dipeptidyl peptidase-4 inhibitor in patients with type 2 diabetes mellitus: An open-label, phase 3 exploratory study.

PubMed

Inagaki, Nobuya; Sano, Hiroki; Seki, Yoshifumi; Kuroda, Shingo; Kaku, Kohei

2018-03-01

Trelagliptin, a novel once-weekly oral dipeptidyl peptidase-4 (DPP-4) inhibitor, has shown favorable efficacy and safety in type 2 diabetes mellitus patients. Trelagliptin was launched in Japan, and is expected to be initially used for switchover from a daily DPP-4 inhibitor in the clinical setting. Thus, the present study was carried out to explore the efficacy and safety of trelagliptin after a daily DPP-4 inhibitor was switched to it. This was an open-label, phase 3 exploratory study to evaluate the efficacy and safety of trelagliptin in Japanese type 2 diabetes mellitus patients who had stable glycemic control on once-daily sitagliptin therapy. Eligible patients received trelagliptin 100 mg orally before breakfast once a week for 12 weeks. The primary end-point was blood glucose by the meal tolerance test, and additional end-points were glycemic control (efficacy) and safety. Altogether, 14 patients received the study drug. The blood glucose did not markedly change from baseline at major assessment points in the meal tolerance test, and a decrease in blood glucose was observed at several other assessment points. Adverse events were reported in 42.9% (6/14) of patients, but all adverse events were mild or moderate in severity, and most were not related to the study drug. No cases of death, serious adverse events or hypoglycemia were reported. It is considered possible to switch a once-daily DPP-4 inhibitor to trelagliptin in type 2 diabetes mellitus patients with stable glycemic control in combination with diet and exercise therapy without any major influences on glycemic control or safety. © 2017 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.

Macrocarpal C isolated from Eucalyptus globulus inhibits dipeptidyl peptidase 4 in an aggregated form.

PubMed

Kato, Eisuke; Kawakami, Kazuhiro; Kawabata, Jun

2018-12-01

Dipeptidyl peptidase 4 (DPP-4) inhibitors are used for the treatment of type-2 diabetes mellitus. Various synthetic inhibitors have been developed to date, and plants containing natural DPP-4 inhibitors have also been identified. Here, 13 plant samples were tested for their DPP-4 inhibitory activity. Macrocarpals A-C were isolated from Eucalyptus globulus through activity-guided fractionation and shown to be DPP-4 inhibitors. Of these, macrocarpal C showed the highest inhibitory activity, demonstrating an inhibition curve characterised by a pronounced increase in activity within a narrow concentration range. Evaluation of macrocarpal C solution by turbidity, nuclear magnetic resonance spectroscopy and mass spectrometry indicated its aggregation, which may explain the characteristics of the inhibition curve. These findings will be valuable for further study of potential small molecule DPP-4 inhibitors.

Cardiovascular effects of anti-diabetes drugs

PubMed Central

Younk, Lisa M.; Lamos, Elizabeth M.

2016-01-01

Introduction Cardiovascular disease remains the major contributor to morbidity and mortality in diabetes. From the need to reduce cardiovascular risk in diabetes and to ensure that such risk is not exacerbated by drug treatments, governmental regulators and drug manufacturers have focused on clinical trials evaluating cardiovascular outcomes. Areas covered Findings from mechanistic and clinical trials of biguanides, sulfonylureas, thiazolidinediones, dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, and sodium-glucose transporter 2 (SGLT-2) inhibitors will be reviewed. These drug classes will be compared within the context of available cardiovascular outcomes data. Clinical implications of new study regulations will be examined. Expert opinion Recent cardiovascular studies provide a more comprehensive evaluation of specific anti-diabetes therapy in individuals with high cardiovascular risk. Long-term effects of anti-hyperglycemic agents in patients with lower cardiovascular risk are still speculative. Historical data supports continued use of metformin as a first-line agent. DPP-4 inhibitors and GLP-1 receptor agonists appear to have neutral effects on cardiovascular outcomes. The significantly decreased cardiovascular risk associated with empagliflozin SGLT-2 inhibitor therapy is impressive and may change how practitioners prescribe add-on therapy to metformin. PMID:27268470

Effects of Incretin-Based Therapies and SGLT2 Inhibitors on Skeletal Health.

PubMed

Egger, Andrea; Kraenzlin, Marius E; Meier, Christian

2016-12-01

Anti-diabetic drugs are widely used and are essential for adequate glycemic control in patients with type 2 diabetes. Recently, marketed anti-diabetic drugs include incretin-based therapies (GLP-1 receptor agonists and DPP-4 inhibitors) and sodium-glucose co-transporter 2 (SGLT2) inhibitors. In contrast to well-known detrimental effects of thiazolidinediones on bone metabolism and fracture risk, clinical data on the safety of incretin-based therapies is limited. Based on meta-analyses of trials investigating the glycemic-lowering effect of GLP-1 receptor agonists and DPP4 inhibitors, it seems that incretin-based therapies are not associated with an increase in fracture risk. Sodium-glucose co-transporter 2 inhibitors may alter calcium and phosphate homeostasis as a result of secondary hyperparathyroidism induced by increased phosphate reabsorption. Although these changes may suggest detrimental effects of SGLT-2 inhibitors on skeletal integrity, treatment-related direct effects on bone metabolism seem unlikely. Observed changes in BMD, however, seem to result from increased bone turnover in the early phase of drug-induced weight loss. Fracture risk, which is observed in older patients with impaired renal function and elevated cardiovascular disease risk treated with SGLT2 inhibitors, seems to be independent of direct effects on bone but more likely to be associated with falls and changes in hydration status secondary to osmotic diuresis.

Efficacy and safety of canagliflozin when used in conjunction with incretin-mimetic therapy in patients with type 2 diabetes.

PubMed

Fulcher, G; Matthews, D R; Perkovic, V; de Zeeuw, D; Mahaffey, K W; Mathieu, C; Woo, V; Wysham, C; Capuano, G; Desai, M; Shaw, W; Vercruysse, F; Meininger, G; Neal, B

2016-01-01

To assess the efficacy and safety of canagliflozin, a sodium glucose co-transporter 2 (SGLT2) inhibitor, in patients with type 2 diabetes enrolled in the CANagliflozin cardioVascular Assessment Study (CANVAS) who were on an incretin mimetic [dipeptidyl peptidase-4 (DPP-4) inhibitor or glucagon-like peptide-1 (GLP-1) receptor agonist]. CANVAS is a double-blind, placebo-controlled study that randomized participants to canagliflozin 100 or 300 mg or placebo added to routine therapy. The present post hoc analysis assessed the efficacy and safety of canagliflozin 100 and 300 mg compared with placebo in subsets of patients from CANVAS who were taking background DPP-4 inhibitors or GLP-1 receptor agonists with or without other antihyperglycaemic agents at week 18. Of the 4330 patients in CANVAS, 316 were taking DPP-4 inhibitors and 95 were taking GLP-1 receptor agonists. At 18 weeks, canagliflozin 100 and 300 mg provided larger placebo-subtracted reductions in glycated haemoglobin (HbA1c) in patients taking DPP-4 inhibitors [-0.56% (95% confidence interval [CI]: -0.77, -0.35), and -0.75% (95% CI: -0.95, -0.54), respectively] and GLP-1 receptor agonists [-1.00% (95% CI: -1.35, -0.65), and -1.06% (95% CI: -1.43, -0.69), respectively]. Body weight and blood pressure (BP) reductions were seen with canagliflozin versus placebo in both subsets. Higher incidences of genital mycotic infections and osmotic diuresis-related adverse events (AEs) were seen with canagliflozin compared with placebo. The incidence of hypoglycaemia was numerically higher with canagliflozin versus placebo; nearly all events occurred in patients on background insulin or insulin secretagogues. In patients on background incretin mimetics, canagliflozin improved HbA1c, body weight and BP, with an increased incidence of AEs related to SGLT2 inhibition. © 2015 John Wiley & Sons Ltd.

Structure⁻Activity Relationship and Molecular Docking of Natural Product Library Reveal Chrysin as a Novel Dipeptidyl Peptidase-4 (DPP-4) Inhibitor: An Integrated In Silico and In Vitro Study.

PubMed

Kalhotra, Poonam; Chittepu, Veera C S R; Osorio-Revilla, Guillermo; Gallardo-Velázquez, Tzayhri

2018-06-06

Numerous studies indicate that diets with a variety of fruits and vegetables decrease the incidence of severe diseases, like diabetes, obesity, and cancer. Diets contain a variety of bioactive compounds, and their features, like diverge scaffolds, and structural complexity make them the most successful source of potential leads or hits in the process of drug discovery and drug development. Recently, novel serine protease dipeptidyl peptidase-4 (DPP-4) inhibitors played a role in the management of diabetes, obesity, and cancer. This study describes the development of field template, field-based qualitative structure⁻activity relationship (SAR) model demonstrating DPP-4 inhibitors of natural origin, and the same model is used to screen virtually focused food database composed of polyphenols as potential DPP-4 inhibitors. Compounds’ similarity to field template, and novelty score “high and very high”, were used as primary criteria to identify novel DPP-4 inhibitors. Molecular docking simulations were performed on the resulting natural compounds using FlexX algorithm. Finally, one natural compound, chrysin, was chosen to be evaluated experimentally to demonstrate the applicability of constructed SAR model. This study provides the molecular insights necessary in the discovery of new leads as DPP-4 inhibitors, to improve the potency of existing DPP-4 natural inhibitors.

DPP4 in Diabetes

PubMed Central

Röhrborn, Diana; Wronkowitz, Nina; Eckel, Juergen

2015-01-01

Dipeptidyl-peptidase 4 (DPP4) is a glycoprotein of 110 kDa, which is ubiquitously expressed on the surface of a variety of cells. This exopeptidase selectively cleaves N-terminal dipeptides from a variety of substrates, including cytokines, growth factors, neuropeptides, and the incretin hormones. Expression of DPP4 is substantially dysregulated in a variety of disease states including inflammation, cancer, obesity, and diabetes. Since the incretin hormones, glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide (GIP), are major regulators of post-prandial insulin secretion, inhibition of DPP4 by the gliptin family of drugs has gained considerable interest for the therapy of type 2 diabetic patients. In this review, we summarize the current knowledge on the DPP4–incretin axis and evaluate most recent findings on DPP4 inhibitors. Furthermore, DPP4 as a type II transmembrane protein is also known to be cleaved from the cell membrane involving different metalloproteases in a cell-type-specific manner. Circulating, soluble DPP4 has been identified as a new adipokine, which exerts both para- and endocrine effects. Recently, a novel receptor for soluble DPP4 has been identified, and data are accumulating that the adipokine-related effects of DPP4 may play an important role in the pathogenesis of cardiovascular disease. Importantly, circulating DPP4 is augmented in obese and type 2 diabetic subjects, and it may represent a molecular link between obesity and vascular dysfunction. A critical evaluation of the impact of circulating DPP4 is presented, and the potential role of DPP4 inhibition at this level is also discussed. PMID:26284071

Head-to-head comparison of structurally unrelated dipeptidyl peptidase 4 inhibitors in the setting of renal ischemia reperfusion injury.

PubMed

Reichetzeder, Christoph; von Websky, Karoline; Tsuprykov, Oleg; Mohagheghi Samarin, Azadeh; Falke, Luise Gabriele; Dwi Putra, Sulistyo Emantoko; Hasan, Ahmed Abdallah; Antonenko, Viktoriia; Curato, Caterina; Rippmann, Jörg; Klein, Thomas; Hocher, Berthold

2017-07-01

Results regarding protective effects of dipeptidyl peptidase 4 (DPP4) inhibitors in renal ischaemia-reperfusion injury (IRI) are conflicting. Here we have compared structurally unrelated DPP4 inhibitors in a model of renal IRI. IRI was induced in uninephrectomized male rats by renal artery clamping for 30 min. The sham group was uninephrectomized but not subjected to IRI. DPP4 inhibitors or vehicle were given p.o. once daily on three consecutive days prior to IRI: linagliptin (1.5 mg·kg -1 ·day -1 ), vildagliptin (8 mg·kg -1 ·day -1 ) and sitagliptin (30 mg·kg -1 ·day -1 ). An additional group received sitagliptin until study end (before IRI: 30 mg·kg -1 ·day -1 ; after IRI: 15 mg·kg -1 ·day -1 ). Plasma-active glucagon-like peptide type 1 (GLP-1) increased threefold to fourfold in all DPP4 inhibitor groups 24 h after IRI. Plasma cystatin C, a marker of GFR, peaked 48 h after IRI. Compared with the placebo group, DPP4 inhibition did not reduce increased plasma cystatin C levels. DPP4 inhibitors ameliorated histopathologically assessed tubular damage with varying degrees of drug-specific efficacies. Renal osteopontin expression was uniformly reduced by all DPP4 inhibitors. IRI-related increased renal cytokine expression was not decreased by DPP4 inhibition. Renal DPP4 activity at study end was significantly inhibited in the linagliptin group, but only numerically reduced in the prolonged/dose-adjusted sitagliptin group. Active GLP-1 plasma levels at study end were increased only in the prolonged/dose-adjusted sitagliptin treatment group. In rats with renal IRI, DPP4 inhibition did not alter plasma cystatin C, a marker of glomerular function, but may protect against tubular damage. © 2017 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.

Inadequate Triglyceride Management Worsens the Durability of Dipeptidyl Peptidase-4 Inhibitor in Subjects with Type 2 Diabetes Mellitus.

PubMed

Shimoda, Masashi; Miyoshi-Takai, Maiko; Irie, Shintaro; Tanabe, Akihito; Obata, Atsushi; Okauchi, Seizo; Hirukawa, Hidenori; Kimura, Tomohiko; Kohara, Kenji; Kamei, Shinji; Mune, Tomoatsu; Kaku, Kohei; Kaneto, Hideaki

2017-01-01

Dipeptidyl peptidase-4 (DPP-4) inhibitors are often used all over the world and exert various beneficial effects including glucose-lowering effect in many subjects with type 2 diabetes. It is poorly understood, however, which factors are closely related with the durability of glucose-lowering effect by DPP-4 inhibitor. In this study, we examined retrospectively which factors could mainly influence the durability of DPP-4 inhibitor. We enrolled 212 participants with type 2 diabetes to whom DPP-4 inhibitor was administered for over 1 year without an addition or increase of other hypoglycemic agents. Age and baseline HbA1c level were significantly higher in the effective group than those in the ineffective group. The effective group had a tendency of smaller amounts of weight change, average total cholesterol, and average triglyceride compared with the ineffective group. Multiple logistic regression analysis showed that average triglyceride and baseline HbA1c were independent predictors associated with the durability of DPP-4 inhibitor. Moreover, an average triglyceride level contributed to the durability of DPP-4 inhibitor in the obese group (BMI ≥ 25 kg/m 2 ) but not in the nonobese group (BMI < 25 kg/m 2 ). These results suggest the importance of strict triglyceride management to maintain the durability of glucose-lowering effect by DPP-4 inhibitor, especially in obese subjects with type 2 diabetes.

Left ventricular diastolic function in patients with type 2 diabetes treated with a dipeptidyl peptidase-4 inhibitor- a pilot study.

PubMed

Nogueira, Katia Camarano; Furtado, Meive; Fukui, Rosa Tsuneshiro; Correia, Marcia Regina Silva; Dos Santos, Rosa Ferreira; Andrade, José Lázaro; Rossi da Silva, Maria Elizabeth

2014-01-01

Blood glucose control is fundamental albeit not enough to prevent diabetic macrovascular complications. Dipeptidyl peptidase-4 (DPP-4) inhibitors are effective in improving metabolic parameters in patients with type 2 diabetes mellitus (T2DM) but little is known about its cardiovascular effects. We compared the DPP-4 inhibitor sitagliptin with bedtime NPH insulin (NPH) as add-on therapy in patients with T2DM, aiming to ascertain which drug would have additional cardioprotective effects. Thirty-five T2DM patients inadequately controlled with metformin plus glyburide were randomized to receive sitagliptin (n = 18) or NPH (n = 17) for 24 weeks. Fasting plasma glucose, HbA1c, lipid profile, C-reactive protein, active glucagon-like peptide (aGLP-1) levels, 24-hour ambulatory blood pressure measurement and comprehensive 2-dimensional echocardiogram were determined before and after treatments. Both sitagliptin and NPH therapies decreased HbA1c levels after 24 weeks. Fasting plasma glucose and triglyceride levels decreased in the NPH group whereas only sitagliptin increased aGLP-1 levels. Left ventricular diastolic dysfunction (LVDD) was detected in 58.6% of twenty-nine patients evaluated. Beneficial effects in LVDD were observed in 75% and 11% of patients treated with sitagliptin and NPH, respectively (p = 0.015). Neither therapy changed C-reactive protein or blood pressure. Sitagliptin and bedtime NPH were similarly effective on glucose control. Improvement in LVDD in T2DM patients treated with sitagliptin was suggested, probably related to the increase of aGLP-1 levels. Therefore, DPP-4 inhibitor seems to have cardioprotective effects independent of glucose control and may have a role in the prevention of diabetic cardiomyopathy.

Soluble DPP-4 up-regulates toll-like receptors and augments inflammatory reactions, which are ameliorated by vildagliptin or mannose-6-phosphate.

PubMed

Lee, Dong-Sung; Lee, Eun-Sol; Alam, Md Morshedul; Jang, Jun-Hyeog; Lee, Ho-Sub; Oh, Hyuncheol; Kim, Youn-Chul; Manzoor, Zahid; Koh, Young-Sang; Kang, Dae-Gil; Lee, Dae Ho

2016-02-01

Studies have shown that dipeptidyl peptidase-4 (DPP-4) inhibitors have anti-inflammatory effects. Soluble DPP-4 (sDPP-4) has been considered as an adipokine of which actions need to be further characterized. We investigated the pro-inflammatory actions of sDPP-4 and the anti-inflammatory effects of DPP-4 inhibition, using vildagliptin, as an enzymatic inhibitor, and mannose-6-phosphate (M6P) as a competitive binding inhibitor. In lipopolysaccharide (LPS)-stimulated RAW264.7 cells, vildagliptin suppressed the increased expression of inducible nitric oxide synthase (iNOS) and phosphorylated JNK (pJNK), activation of the NF-κB pathway, and the resultant NO and proinflammatory cytokine production. Although sDPP-4 alone did not affect the protein level of iNOS or pJNK or the production of NO in RAW264.7 cells, it did amplify iNOS expression, NO responses, and proinflammatory cytokine production in LPS-stimulated RAW264 cells. As a probable mechanism, we found that sDPP-4 caused dose-dependent increases in the expression levels of toll-like receptor 4 (TLR4) and TLR2 in RAW264.7 cells, and that these alterations were inhibited by vildagliptin, M6P, or bisindolylmaleimide II, a protein kinase C inhibitor. Either vildagliptin or M6P suppressed iNOS expression and NO and cytokine production in LPS+DPP-4-co-stimulated macrophages, while combined treatment of the co-stimulated cells with both agents had increased anti-inflammatory effects compared with either treatment alone. Intravenous injection of sDPP-4 to C57BL/6J mice increased the expression of both TLRs in kidney and white adipose tissues. Our findings suggest that sDPP-4 enhances inflammatory actions via TLR pathway, while DPP-4 inhibition with either an enzymatic or binding inhibitor has anti-inflammatory effects. Copyright © 2015 Elsevier Inc. All rights reserved.

Finding a Potential Dipeptidyl Peptidase-4 (DPP-4) Inhibitor for Type-2 Diabetes Treatment Based on Molecular Docking, Pharmacophore Generation, and Molecular Dynamics Simulation

PubMed Central

Meduru, Harika; Wang, Yeng-Tseng; Tsai, Jeffrey J. P.; Chen, Yu-Ching

2016-01-01

Dipeptidyl peptidase-4 (DPP-4) is the vital enzyme that is responsible for inactivating intestinal peptides glucagon like peptide-1 (GLP-1) and Gastric inhibitory polypeptide (GIP), which stimulates a decline in blood glucose levels. The aim of this study was to explore the inhibition activity of small molecule inhibitors to DPP-4 following a computational strategy based on docking studies and molecular dynamics simulations. The thorough docking protocol we applied allowed us to derive good correlation parameters between the predicted binding affinities (pKi) of the DPP-4 inhibitors and the experimental activity values (pIC50). Based on molecular docking receptor-ligand interactions, pharmacophore generation was carried out in order to identify the binding modes of structurally diverse compounds in the receptor active site. Consideration of the permanence and flexibility of DPP-4 inhibitor complexes by means of molecular dynamics (MD) simulation specified that the inhibitors maintained the binding mode observed in the docking study. The present study helps generate new information for further structural optimization and can influence the development of new DPP-4 inhibitors discoveries in the treatment of type-2 diabetes. PMID:27304951

Finding a Potential Dipeptidyl Peptidase-4 (DPP-4) Inhibitor for Type-2 Diabetes Treatment Based on Molecular Docking, Pharmacophore Generation, and Molecular Dynamics Simulation.

PubMed

Meduru, Harika; Wang, Yeng-Tseng; Tsai, Jeffrey J P; Chen, Yu-Ching

2016-06-13

Dipeptidyl peptidase-4 (DPP-4) is the vital enzyme that is responsible for inactivating intestinal peptides glucagon like peptide-1 (GLP-1) and Gastric inhibitory polypeptide (GIP), which stimulates a decline in blood glucose levels. The aim of this study was to explore the inhibition activity of small molecule inhibitors to DPP-4 following a computational strategy based on docking studies and molecular dynamics simulations. The thorough docking protocol we applied allowed us to derive good correlation parameters between the predicted binding affinities (pKi) of the DPP-4 inhibitors and the experimental activity values (pIC50). Based on molecular docking receptor-ligand interactions, pharmacophore generation was carried out in order to identify the binding modes of structurally diverse compounds in the receptor active site. Consideration of the permanence and flexibility of DPP-4 inhibitor complexes by means of molecular dynamics (MD) simulation specified that the inhibitors maintained the binding mode observed in the docking study. The present study helps generate new information for further structural optimization and can influence the development of new DPP-4 inhibitors discoveries in the treatment of type-2 diabetes.

Efficacy of dipeptidyl-peptidase-4 inhibitors and impact on β-cell function in Asian and Caucasian type 2 diabetes mellitus patients: A meta-analysis.

PubMed

Cai, Xiaoling; Han, Xueyao; Luo, Yingying; Ji, Linong

2015-05-01

This work aimed to compare the efficacy of dipeptidyl peptidase-IV (DPP-4) inhibitors and their impact on β-cell function in Asian and Caucasian patients with type 2 diabetes mellitus. Databases were systematically searched and qualifying studies that compared DPP-4 inhibitors with other antidiabetic medications in type 2 diabetes were included. A total of 68 studies were included in the meta-analysis. Comparison of DPP-4 inhibitors with placebo in Asian patients showed a decrease in glycosylated hemoglobin (HbA1c ) favoring DPP-4 inhibitors (weighted mean difference [WMD], -0.81%; 95% confidence interval [CI], -0.95% to -0.68%; P < 0.001). Comparison of HbA1c changes between Asian and Caucasian patients showed a significant between-group difference of -0.18% (95% CI, -0.32% to -0.04%; P = 0.011) when compared with placebo. In Asian patients, the homeostatic model assessment for β-cell function (HOMA-β) was increased with DPP-4 inhibitors compared with placebo (WMD, 7.90; 95% CI, 4.29 to 11.51; P < 0.001), although to a lesser extent in Caucasian patients. Comparisons between Asian and Caucasian patients showed a significant between-group difference of -4.97 (95% CI, -9.86 to -0.09; P = 0.046) compared with placebo. Body weight increase with DPP-4 inhibitors compared with placebo was comparable in Asian and Caucasian studies (WMD, 0.37 kg and 0.45 kg and 95% CI, 0.04-0.69 and 0.27-0.62, respectively). The glucose-lowering efficacy of DPP-4 inhibitors was greater in Asian patients than in Caucasian patients, although the effect on β-cell function was inferior in Asian patients. The effect of DPP-4 inhibitors on insulin resistance and body weight in Asian patients was comparable with that observed in Caucasian patients. © 2014 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

Discovery of 2-[4-{{2-(2S,5R)-2-cyano-5-ethynyl-1-pyrrolidinyl]-2-oxoethyl]amino]- 4-methyl-1-piperidinyl]-4-pyridinecarboxylic acid (ABT-279): a very potent, selective, effective, and well-tolerated inhibitor of dipeptidyl peptidase-IV, useful for the treatment of diabetes.

PubMed

Madar, David J; Kopecka, Hana; Pireh, Daisy; Yong, Hong; Pei, Zhonghua; Li, Xiaofeng; Wiedeman, Paul E; Djuric, Stevan W; Von Geldern, Thomas W; Fickes, Michael G; Bhagavatula, Lakshmi; McDermott, Todd; Wittenberger, Steven; Richards, Steven J; Longenecker, Kenton L; Stewart, Kent D; Lubben, Thomas H; Ballaron, Stephen J; Stashko, Michael A; Long, Michelle A; Wells, Heidi; Zinker, Bradley A; Mika, Amanda K; Beno, David W A; Kempf-Grote, Anita J; Polakowski, James; Segreti, Jason; Reinhart, Glenn A; Fryer, Ryan M; Sham, Hing L; Trevillyan, James M

2006-10-19

Dipeptidyl peptidase-IV (DPP-IV) inhibitors are poised to be the next major drug class for the treatment of type 2 diabetes. Structure-activity studies of substitutions at the C5 position of the 2-cyanopyrrolidide warhead led to the discovery of potent inhibitors of DPP-IV that lack activity against DPP8 and DPP9. Further modification led to an extremely potent (Ki(DPP)(-)(IV) = 1.0 nM) and selective (Ki(DPP8) > 30 microM; Ki(DPP9) > 30 microM) clinical candidate, ABT-279, that is orally available, efficacious, and remarkably safe in preclinical safety studies.

Incretin-Based Therapies for Diabetic Complications: Basic Mechanisms and Clinical Evidence

PubMed Central

Kawanami, Daiji; Matoba, Keiichiro; Sango, Kazunori; Utsunomiya, Kazunori

2016-01-01

An increase in the rates of morbidity and mortality associated with diabetic complications is a global concern. Glycemic control is important to prevent the development and progression of diabetic complications. Various classes of anti-diabetic agents are currently available, and their pleiotropic effects on diabetic complications have been investigated. Incretin-based therapies such as dipeptidyl peptidase (DPP)-4 inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1RA) are now widely used in the treatment of patients with type 2 diabetes. A series of experimental studies showed that incretin-based therapies have beneficial effects on diabetic complications, independent of their glucose-lowering abilities, which are mediated by anti-inflammatory and anti-oxidative stress properties. Based on these findings, clinical studies to assess the effects of DPP-4 inhibitors and GLP-1RA on diabetic microvascular and macrovascular complications have been performed. Several but not all studies have provided evidence to support the beneficial effects of incretin-based therapies on diabetic complications in patients with type 2 diabetes. We herein discuss the experimental and clinical evidence of incretin-based therapy for diabetic complications. PMID:27483245

Safety evaluation of trelagliptin in the treatment of Japanese type 2 diabetes mellitus patients.

PubMed

Kaku, Kohei

2017-11-01

Trelagliptin is a novel, long-acting dipeptidyl peptidase-4 (DPP-4) inhibitor approved for the treatment of type 2 diabetes mellitus (T2DM) in japan. The safety and efficacy of trelagliptin has been evaluated in three published clinical trials to date: one phase II and two phase III studies. As trelagliptin only requires dosing once per week, this new agent has the potential to improve compliance and subsequently, glycaemic control, in patients with T2DM. Areas covered: This article reviews the available safety data for trelagliptin from published clinical trials, and evaluates the published safety profile relative to competitor once-daily and once-weekly DPP-4 inhibitors. Expert opinion: Clinical trial data to date suggest that trelagliptin is a safe and efficacious medication with a similar safety profile to once-daily DPP-4 inhibitors, and to the once-weekly DPP-4 inhibitor, omarigliptin. Trelagliptin is well tolerated when given alone, and in combination with other anti-diabetic medications. An advantage of trelagliptin over existing once-daily DPP-4 inhibitors is the decrease of dosing frequency, rather than once-daily. No specific, serious adverse events have been reported for trelagliptin in published clinical trials, making it an attractive alternative to other DPP-4 inhibitors.

Berry and Citrus Phenolic Compounds Inhibit Dipeptidyl Peptidase IV: Implications in Diabetes Management

PubMed Central

Fan, Junfeng; Lila, Mary Ann; Yousef, Gad

2013-01-01

Beneficial health effects of fruits and vegetables in the diet have been attributed to their high flavonoid content. Dipeptidyl peptidase IV (DPP-IV) is a serine aminopeptidase that is a novel target for type 2 diabetes therapy due to its incretin hormone regulatory effects. In this study, well-characterized anthocyanins (ANC) isolated from berry wine blends and twenty-seven other phenolic compounds commonly present in citrus, berry, grape, and soybean, were individually investigated for their inhibitory effects on DPP-IV by using a luminescence assay and computational modeling. ANC from blueberry-blackberry wine blends strongly inhibited DPP-IV activity (IC50, 0.07 ± 0.02 to >300 μM). Of the twenty-seven phenolics tested, the most potent DPP-IV inhibitors were resveratrol (IC50, 0.6 ± 0.4 nM), luteolin (0.12 ± 0.01 μM), apigenin (0.14 ± 0.02 μM), and flavone (0.17 ± 0.01 μM), with IC50 values lower than diprotin A (4.21 ± 2.01 μM), a reference standard inhibitory compound. Analyses of computational modeling showed that resveratrol and flavone were competitive inhibitors which could dock directly into all three active sites of DPP-IV, while luteolin and apigenin docked in a noncompetitive manner. Hydrogen bonding was the main binding mode of all tested phenolic compounds with DPP-IV. These results indicate that flavonoids, particularly luteolin, apigenin, and flavone, and the stilbenoid resveratrol can act as naturally occurring DPP-IV inhibitors. PMID:24069048

E3024, 3-but-2-ynyl-5-methyl-2-piperazin-1-yl-3,5-dihydro-4H-imidazo[4,5-d]pyridazin-4-one tosylate, is a novel, selective and competitive dipeptidyl peptidase-IV inhibitor.

PubMed

Yasuda, Nobuyuki; Nagakura, Tadashi; Inoue, Takashi; Yamazaki, Kazuto; Katsutani, Naruo; Takenaka, Osamu; Clark, Richard; Matsuura, Fumiyoshi; Emori, Eita; Yoshikawa, Seiji; Kira, Kazunobu; Ikuta, Hironori; Okada, Toshimi; Saeki, Takao; Asano, Osamu; Tanaka, Isao

2006-10-24

Dipeptidyl peptidase IV (DPP-IV) inhibitors are expected to become a useful new class of anti-diabetic agent. The aim of the present study is to characterize the in vitro and in vivo profile of E3024, 3-but-2-ynyl-5-methyl-2-piperazin-1-yl-3,5-dihydro-4H-imidazo[4,5-d]pyridazin-4-one tosylate, which is a novel imidazopyridazinone-derived DPP-IV inhibitor. E3024 inhibited recombinant human and mouse DPP-IV with IC50 values of approximately 100 nM. E3024 inhibited DPP-IV in human, mouse, rat and canine plasma with IC50 values of 140 to 400 nM. In contrast, E3024 did not inhibit DPP-8 or DPP-9 activity. Kinetic analysis indicated that E3024 is a competitive DPP-IV inhibitor. In Zucker fa/fa rats, E3024 (1 mg/kg) reduced glucose excursion after glucose load, with increases in plasma insulin and active glucagon-like peptide-1 levels. In fasted rats, this compound did not cause hypoglycemia. In a rat 4-week toxicological study, no notable changes were found at doses up to 750 mg/kg. The present preclinical studies indicate that E3024 is a novel selective DPP-IV inhibitor with anti-diabetic effects and a good safety profile.

Design, synthesis and biological evaluation of novel pyrazolo-pyrimidinones as DPP-IV inhibitors in diabetes.

PubMed

Sagar, Sneha R; Agarwal, Jessica K; Pandya, Dhaivat H; Dash, Ranjeet Prasad; Nivsarkar, Manish; Vasu, Kamala K

2015-10-15

We report the design, synthesis, biological activity and docking studies of series of novel pyrazolo[3,4-d]pyrimidinones as DPP-IV inhibitors in diabetes. Molecules were synthesized and evaluated for their DPP-IV inhibition activity. Compounds 5e, 5k, 5o and 6a were found to be potent inhibitors of DPP-IV enzyme. Amongst all the synthesized compounds, 6-methyl-5-(4-methylpyridin-2-yl)-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one (5k) was found to be the most active based on in vitro DPP-IV studies and also exhibited promising in vivo blood glucose lowering activity in male Wistar rats. Copyright © 2015. Published by Elsevier Ltd.

Comparisons of the efficacy of glucose control, lipid profile, and β-cell function between DPP-4 inhibitors and AGI treatment in type 2 diabetes patients: a meta-analysis.

PubMed

Cai, Xiaoling; Yang, Wenjia; Zhou, Lingli; Zhang, Simin; Han, Xueyao; Ji, Linong

2015-12-01

The aim of this study is to compare the efficacy of dipeptidyl peptidase-4 (DPP-4) inhibitor treatment with α-glucosidase inhibitor (AGI) treatment in patients with type 2 diabetes through a meta-analysis. Studies were identified by a literature search of Medline, Embase, and others from the time that recording commenced until December 2014. The meta-analysis was performed by computing the weighted mean difference (WMD) and 95 % confidence interval (CI) for a change from baseline to the study endpoint for DPP-4 inhibitors versus AGIs. Nine randomized controlled trial were judged to be appropriate for inclusion in the meta-analysis. One thousand and forty-six patients were treated with a DPP-4 inhibitor, while 929 patients were treated with AGI treatment; the groups had a comparable baseline body mass index of 25.5 ± 1.3 kg/m(2) and mean baseline HbA1c of 7.83 ± 0.53 %. Treatment with DPP-4 inhibitors led to a significantly greater change from baseline in the HbA1c levels (WMD -0.30 %; 95 % CI -0.47 to -0.13 %, p < 0.001) and fasting plasma glucose levels (WMD -0.50 mmol/L; 95 % CI -0.89 to -0.11 mmol/L, p = 0.01) compared with AGI treatment. Compared with AGIs, treatment with DPP-4 inhibitors was associated with a significantly greater increase in the weight change from baseline (WMD 0.89 kg; 95 % CI 0.53-1.25, p < 0.001). Treatment with DPP-4 inhibitors was associated with a significantly greater increase in the fasting insulin level from baseline (WMD 0.63 µU/mL; 95 % CI 0.35-0.90 µU/mL, p < 0.001). DPP-4 inhibitors significantly improved homeostatic model assessment for β-cell function in type 2 diabetes patients compared with AGI treatment (WMD 5.43; 95 % CI 1.01-9.85, p = 0.02). DPP-4 inhibitors were associated with a significantly greater decrease in the cholesterol (CHO) level (WMD -0.19 mmol/L; 95 % CI -0.19 to -0.19 mmol/L, p < 0.001) and a significantly greater decrease in the low-density lipoprotein cholesterol (LDL-C) level (WMD -0.16 mmol/L; 95 % CI -0.26 to -0.05 mmol/L, p = 0.003). Compared with AGIs (813 participants), treatment with DPP-4 inhibitors (1031 participants) was associated with a significantly lower incidence of drug-related adverse event (OR 0.48; 95 % CI 0.36-0.64, p < 0.0001). The efficacy of glucose control and improvement of β-cell function, as well as total CHO and LDL-C decreases, in DPP-4 inhibitor treatment were superior to those with AGI treatment, and there was a lower incidence of drug-related AE.

Dipeptidyl peptidase 4 - An important digestive peptidase in Tenebrio molitor larvae.

PubMed

Tereshchenkova, Valeriia F; Goptar, Irina A; Kulemzina, Irina A; Zhuzhikov, Dmitry P; Serebryakova, Marina V; Belozersky, Mikhail A; Dunaevsky, Yakov E; Oppert, Brenda; Filippova, Irina Yu; Elpidina, Elena N

2016-09-01

Dipeptidyl peptidase 4 (DPP 4) is a proline specific serine peptidase that plays an important role in different regulatory processes in mammals. In this report, we isolated and characterized a unique secreted digestive DPP 4 from the anterior midgut of a stored product pest, Tenebrio molitor larvae (TmDPP 4), with a biological function different than that of the well-studied mammalian DPP 4. The sequence of the purified enzyme was confirmed by mass-spectrometry, and was identical to the translated RNA sequence found in a gut EST database. The purified peptidase was characterized according to its localization in the midgut, and substrate specificity and inhibitor sensitivity were compared with those of human recombinant DPP 4 (rhDPP 4). The T. molitor enzyme was localized mainly in the anterior midgut of the larvae, and 81% of the activity was found in the fraction of soluble gut contents, while human DPP 4 is a membrane enzyme. TmDPP 4 was stable in the pH range 5.0-9.0, with an optimum activity at pH 7.9, similar to human DPP 4. Only specific inhibitors of serine peptidases, diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride, suppressed TmDPP 4 activity, and the specific dipeptidyl peptidase inhibitor vildagliptin was most potent. The highest rate of TmDPP 4 hydrolysis was found for the synthetic substrate Arg-Pro-pNA, while Ala-Pro-pNA was a better substrate for rhDPP 4. Related to its function in the insect midgut, TmDPP 4 efficiently hydrolyzed the wheat storage proteins gliadins, which are major dietary proteins of T. molitor. Published by Elsevier Ltd.

Mechanism-based population pharmacokinetic modelling in diabetes: vildagliptin as a tight binding inhibitor and substrate of dipeptidyl peptidase IV

PubMed Central

Landersdorfer, Cornelia B; He, Yan-Ling; Jusko, William J

2012-01-01

AIMS To assess the pharmacokinetics of vildagliptin at different doses and build a mechanism-based population model that simultaneously describes vildagliptin pharmacokinetics and its effects on DPP-4 activity based on underlying physiology and biology. METHODS Vildagliptin concentrations and DPP-4 activity vs. time from 13 type 2 diabetic patients after oral vildagliptin 10, 25 or 100 mg and placebo twice daily for 28 days were co-modelled. NONMEM VI and S-ADAPT were utilized for population modelling. RESULTS A target-mediated drug disposition (TMDD) model accounting for capacity-limited high affinity binding of vildagliptin to DPP-4 in plasma and tissues had good predictive performance. Modelling the full time course of the vildagliptin-DPP-4 interaction suggested parallel vildagliptin dissociation from DPP-4 by a slow first-order process and hydrolysis by DPP-4 to an inactive metabolite as a disposition mechanism. Due to limited amounts of DPP-4, vildagliptin concentrations increased slightly more than dose proportionally. This newly proposed model and the parameter estimates are supported by published in vitro studies. Mean parameter estimates (inter-individual coefficient of variation) were: non-saturable clearance 36 l h−1 (25%), central volume of distribution 22 l (37%), half-life of dissociation from DPP-4 1.1 h (94%) and half-life of hydrolysis 6.3 h (81%). CONCLUSIONS Vildagliptin is both an inhibitor and substrate for DPP-4. By utilizing the TMDD approach, slow dissociation of vildagliptin from DPP-4 was found in patients and the half-life of hydrolysis by DPP-4 estimated. This model can be used to predict DPP-4 inhibition effects of other dosage regimens and be modified for other DPP-4 inhibitors to differentiate their properties. PMID:22442826

Comparative Effectiveness of DPP-4 Inhibitors Versus Sulfonylurea for the Treatment of Type 2 Diabetes in Routine Clinical Practice: A Retrospective Multicenter Real-World Study.

PubMed

Fadini, Gian Paolo; Bottigliengo, Daniele; D'Angelo, Federica; Cavalot, Franco; Bossi, Antonio Carlo; Zatti, Giancarlo; Baldi, Ileana; Avogaro, Angelo

2018-06-01

DPP-4 inhibitors (DPP4i) and sulfonylureas are popular second-line therapies for type 2 diabetes (T2D), but there is a paucity of real-world studies comparing their effectiveness in routine clinical practice. This was a multicenter retrospective study on diabetes outpatient clinics comparing the effectiveness of DPP4i versus gliclazide extended release. The primary endpoint was change from baseline in HbA1c. Secondary endpoints were changes in fasting plasma glucose, body weight, and systolic blood pressure. Automated software extracted data from the same clinical electronic chart system at all centers. Propensity score matching (PSM) was used to generate comparable cohorts to perform outcome analysis. We included data on 2410 patients starting DPP4i and 1590 patients starting gliclazide (mainly 30-60 mg/day). At baseline, the two groups differed in disease duration, body weight, blood pressure, HbA1c, fasting glucose, HDL cholesterol, triglycerides, liver enzymes, eGFR, prevalence of microangiopathy, and use of metformin. Among DPP4i molecules, no difference in glycemic effectiveness was detected. In matched cohorts (n = 1316/group), patients starting DPP4i, as compared with patients starting gliclazide, experienced greater reductions in HbA1c (- 0.6% versus - 0.4%; p < 0.001), fasting glucose (- 14.1 mg/dl versus - 8.8 mg/dl; p = 0.007), and body weight (- 0.4 kg versus - 0.1 kg; p = 0.006) after an average 6 months follow-up. DPP4i improved glucose control more than gliclazide, especially in patients who had failed with other glucose-lowering medications or were on basal insulin. This large retrospective real-world study shows that, in routine clinical practice, starting a DPP4i allows better glycemic control than starting low-dose gliclazide. The Italian Diabetes Society, with external support from AstraZeneca.

Structures of Human DPP7 Reveal the Molecular Basis of Specific Inhibition and the Architectural Diversity of Proline-Specific Peptidases

PubMed Central

Dong, Aiping; Seitova, Almagul; Crombett, Lissete; Shewchuk, Lisa M.; Hassell, Annie M.; Sweitzer, Sharon M.; Sweitzer, Thomas D.; McDevitt, Patrick J.; Johanson, Kyung O.; Kennedy-Wilson, Karen M.; Cossar, Doug; Bochkarev, Alexey; Gruber, Karl; Dhe-Paganon, Sirano

2012-01-01

Proline-specific dipeptidyl peptidases (DPPs) are emerging targets for drug development. DPP4 inhibitors are approved in many countries, and other dipeptidyl peptidases are often referred to as DPP4 activity- and/or structure-homologues (DASH). Members of the DASH family have overlapping substrate specificities, and, even though they share low sequence identity, therapeutic or clinical cross-reactivity is a concern. Here, we report the structure of human DPP7 and its complex with a selective inhibitor Dab-Pip (L-2,4-diaminobutyryl-piperidinamide) and compare it with that of DPP4. Both enzymes share a common catalytic domain (α/β-hydrolase). The catalytic pocket is located in the interior of DPP7, deep inside the cleft between the two domains. Substrates might access the active site via a narrow tunnel. The DPP7 catalytic triad is completely conserved and comprises Ser162, Asp418 and His443 (corresponding to Ser630, Asp708 and His740 in DPP4), while other residues lining the catalytic pockets differ considerably. The “specificity domains” are structurally also completely different exhibiting a β-propeller fold in DPP4 compared to a rare, completely helical fold in DPP7. Comparing the structures of DPP7 and DPP4 allows the design of specific inhibitors and thus the development of less cross-reactive drugs. Furthermore, the reported DPP7 structures shed some light onto the evolutionary relationship of prolyl-specific peptidases through the analysis of the architectural organization of their domains. PMID:22952628

Sitagliptin, a dipeptidyl peptidase-4 inhibitor, improves recognition memory, oxidative stress and hippocampal neurogenesis and upregulates key genes involved in cognitive decline.

PubMed

Gault, V A; Lennox, R; Flatt, P R

2015-04-01

To examine whether prolonged dipeptidyl peptidase-4 (DPP-4) inhibition can reverse learning and memory impairment in high-fat-fed mice. High-fat-fed mice received oral sitagliptin (50 mg/kg body weight) once daily or saline vehicle over 21 days. An additional group of mice on standard chow received saline vehicle. Energy intake, body weight, glucose and insulin concentrations were measured at regular intervals. Glucose tolerance, insulin sensitivity, novel object recognition, DPP-4 activity, hormone analysis, hippocampal gene expression and histology were performed. Sitagliptin decreased circulating DPP-4 activity and improved glucose tolerance, glucose-stimulated insulin secretion and insulin sensitivity, and reduced plasma triglycerides and cholesterol levels. DPP-4 inhibition improved recognition memory (1.2-fold increase) without affecting hypermoteric activity or anxiety levels. Improvement in memory and learning was linked to reduced immunostaining for 8-oxoguanine and increased doublecortin staining in the hippocampus, which were indicative of reduced brain oxidative stress and increased hippocampal neurogenesis, respectively. These effects were associated with significant upregulation of hippocampal gene expression of glucagon-like peptide-1 (GLP-1) receptor, glucose-dependent insulinotropic polypeptide receptor, synaptophysin, sirtuin 1, glycogen synthase kinase 3β, superdioxide mutase 2, nuclear factor (erythroid-derived 2)-like 2 and vascular endothelial growth factor. Total plasma and brain GLP-1 concentrations were significantly increased after sitagliptin therapy, whereas DPP-4 activity in brain tissue was not altered. These studies show that sitagliptin can reverse memory impairment in high-fat-fed mice and is also associated with improved insulin sensitivity, enhanced hippocampal neurogenesis and reduced oxidative stress. DPP-4 inhibitors may therefore exhibit dual benefits by improving metabolic control and reducing the decline in cognitive function. © 2015 John Wiley & Sons Ltd.

Pharmacokinetics in patients with chronic liver disease and hepatic safety of incretin-based therapies for the management of type 2 diabetes mellitus.

PubMed

Scheen, André J

2014-09-01

Patients with type 2 diabetes mellitus have an increased risk of chronic liver disease (CLD) such as non-alcoholic fatty liver disease and steatohepatitis, and about one-third of cirrhotic patients have diabetes. However, the use of several antidiabetic agents, such as metformin and sulphonylureas, may be a concern in case of hepatic impairment (HI). New glucose-lowering agents targeting the incretin system are increasingly used for the management of type 2 diabetes. Incretin-based therapies comprise oral inhibitors of dipeptidyl peptidase-4 (DPP-4) (gliptins) or injectable glucagon-like peptide-1 (GLP-1) receptor agonists. This narrative review summarises the available data regarding the use of both incretin-based therapies in patients with HI. In contrast to old glucose-lowering agents, they were evaluated in specifically designed acute pharmacokinetic studies in patients with various degrees of HI and their hepatic safety was carefully analysed in large clinical trials. Only mild changes in pharmacokinetic characteristics of DPP-4 inhibitors were observed in patients with different degrees of HI, presumably without major clinical relevance. GLP-1 receptor agonists have a renal excretion rather than liver metabolism. Specific pharmacokinetic data in patients with HI are only available for liraglutide. No significant changes in liver enzymes were reported with DPP-4 inhibitors or GLP-1 receptor agonists, alone or in combination with various other glucose-lowering agents, in clinical trials up to 2 years in length. On the contrary, preliminary data suggested that incretin-based therapies may be beneficial in patients with CLD, more particularly in the presence of non-alcoholic fatty liver disease. Nevertheless, caution should be recommended, especially in patients with advanced cirrhosis, because of a lack of clinical experience with incretin-based therapies in these vulnerable patients.

DPP-4 inhibitors improve liver dysfunction in type 2 diabetes mellitus.

PubMed

Kanazawa, Ippei; Tanaka, Ken-ichiro; Sugimoto, Toshitsugu

2014-09-17

Dipeptidyl peptidase-4 (DPP-4) inhibitors might have pleiotropic effects because receptors for incretin exist in various tissues, including liver. We examined whether DPP-4 inhibitors affect liver function in patients with type 2 diabetes. A retrospective review of 459 patients with type 2 diabetes who were prescribed DPP-4 inhibitors was performed. After exclusion of patients with hepatitis B or C, steroid use, and other diseases that might affect liver function and diabetes status, 224 patients were included in the analysis. Forty-four patients (19.6%) with liver injury defined by aspartate transaminase (AST) or alanine transaminase (ALT) over the normal level of 40 U/L. In the patients with liver injury, AST and ALT were significantly decreased after 6 months from the first date of DPP-4 prescription, with mean changes of -6.2 U/L [95% confidence interval (CI) -10.9 to -1.4, p=0.012] and of -11.9 U/L (95%CI -19.5 to -4.2, p=0.003), respectively. Percent changes in AST were significantly and negatively correlated with baseline AST and ALT (r=-0.27, p<0.001 and r=-0.23, p=0.002, respectively), and percent changes in ALT were also negatively correlated with them (r=-0.23, p=0.001 and r=-0.27, p<0.001, respectively). DPP-4 inhibitors improved liver dysfunction in patients with type 2 diabetes.

Safety, effectiveness, and cost of dipeptidyl peptidase-4 inhibitors versus intermediate acting insulin for type 2 diabetes: protocol for a systematic review and network meta-analysis.

PubMed

Tricco, Andrea C; Antony, Jesmin; Soobiah, Charlene; Hemmelgarn, Brenda; Moher, David; Hutton, Brian; Yu, Catherine H; Majumdar, Sumit R; Straus, Sharon E

2013-06-28

Type 2 diabetes mellitus (T2DM) results from insulin resistance and relative insulin deficiency. T2DM treatment is a step-wise approach beginning with lifestyle modifications (for example, diet, exercise), followed by the addition of oral hypoglycemic agents (for example, metformin). Patients who do not respond to first-line therapy are offered second-line therapy (for example, sulfonylureas). Third-line therapy may include insulin and/or dipeptidyl peptidase-4 (DPP-4) inhibitors.It is unclear whether DPP-4 inhibitors are safer and more effective than intermediate acting insulin for third-line management of T2DM. As such, our objective is to evaluate the comparative effectiveness, safety and cost-effectiveness of DPP-4 inhibitors versus intermediate acting insulin for T2DM patients who have failed both first- and second-line diabetes treatments. Electronic searches of MEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, and grey literature (for example, trial registries, public health websites) will be conducted to identify studies examining DPP-4 inhibitors compared with each other, intermediate acting insulin, no treatment, or placebo for adults with T2DM. The outcomes of interest include glycosylated hemoglobin (A1C) (primary outcome), as well as emergency department visits, physician visits, hospital admissions, weight gain, quality of life, microvascular complications, macrovascular complications, all-cause mortality, and cost (secondary outcomes). Randomized clinical trials (RCTs), quasi-RCTs, non-RCTs, controlled before-after, interrupted time series, cohort studies, and cost studies reporting data on these outcomes will be included. Eligibility will not be restricted by publication status, language of dissemination, duration of study follow-up, or time period of study conduct.Two reviewers will screen the titles and abstracts resulting from the literature search, as well as potentially relevant full-text articles, in duplicate. Data will be abstracted and quality will be appraised by two team members independently. Conflicts at all levels of screening and abstraction will be resolved through team discussion.Our results will be described narratively. Random effects meta-analysis and network meta-analysis will be conducted, if feasible and appropriate. Our systematic review results can be used to determine the most effective, safe and cost-effective third-line strategies for managing T2DM. This information will be of great use to health policy-makers and clinicians, as well as patients living with T2DM and their families. PROSPERO registry number: CRD42013003624.

Effectiveness and safety of dipeptidyl peptidase 4 inhibitors in the management of type 2 diabetes in older adults: a systematic review and development of recommendations to reduce inappropriate prescribing.

PubMed

Schott, Gisela; Martinez, Yolanda V; Ediriweera de Silva, R Erandie; Renom-Guiteras, Anna; Vögele, Anna; Reeves, David; Kunnamo, Ilkka; Marttila-Vaara, Minna; Sönnichsen, Andreas

2017-10-16

Preventable drug-related hospital admissions can be associated with drugs used in diabetes and the benefits of strict diabetes control may not outweigh the risks, especially in older populations. The aim of this study was to look for evidence on risks and benefits of DPP-4 inhibitors in older adults and to use this evidence to develop recommendations for the electronic decision support tool of the PRIMA-eDS project. Systematic review using a staged approach which searches for systematic reviews and meta-analyses first, then individual studies only if prior searches were inconclusive. The target population were older people (≥65 years old) with type 2 diabetes. We included studies reporting on the efficacy and/or safety of DPP-4 inhibitors for the management of type 2 diabetes. Studies were included irrespective of DPP-4 inhibitors prescribed as monotherapy or in combination with any other drug for the treatment of type 2 diabetes. The target intervention was DPP-4 inhibitors compared to placebo, no treatment, other drugs to treat type 2 diabetes or a non-pharmacological intervention. Thirty studies (reported in 33 publications) were included: 1 meta-analysis, 17 intervention studies and 12 observational studies. Sixteen studies were focused on older adults and 14 studies reported subgroup analyses in participants ≥65, ≥70, or ≥75 years. Comorbidities were reported by 26 studies and frailty or functional status by one study. There were conflicting findings regarding the effectiveness of DPP-4 inhibitors in older adults. In general, DPP-4 inhibitors showed similar or better safety than placebo and other antidiabetic drugs. However, these safety data are mainly based on short-term outcomes like hypoglycaemia in studies with HbA1c control levels recommended for younger people. One recommendation was developed advising clinicians to reconsider the use of DPP-4 inhibitors for the management of type 2 diabetes in older adults with HbA1c <8.5% because of scarce data on clinically relevant benefits of their use. Twenty-two of the included studies were funded by pharmaceutical companies and authored or co-authored by employees of the sponsor. Other than the surrogate endpoint of improved glycaemic control, data on clinically relevant benefits of DPP-4 inhibitors in the treatment of type 2 diabetes mellitus in older adults is scarce. DPP-4 inhibitors might have a lower risk of hypoglycaemia compared to other antidiabetic drugs but data show conflicting findings for long-term benefits. Further studies are needed that evaluate the risks and benefits of DPP-4 inhibitors for the management of type 2 diabetes mellitus in older adults, using clinically relevant outcomes and including representative samples of older adults with information on their frailty status and comorbidities. Studies are also needed that are independent of pharmaceutical company involvement.

Scaffold-hopping from xanthines to tricyclic guanines: A case study of dipeptidyl peptidase 4 (DPP4) inhibitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pissarnitski, Dmitri A.; Zhao, Zhiqiang; Cole, David

2016-11-01

Molecular modeling of unbound tricyclic guanine scaffolds indicated that they can serve as effective bioisosteric replacements of xanthines. This notion was further confirmed by a combination of X-ray crystallography and SAR studies, indicating that tricyclic guanine DPP4 inhibitors mimic the binding mode of xanthine inhibitors, exemplified by linagliptin. Realization of the bioisosteric relationship between these scaffolds potentially will lead to a wider application of cyclic guanines as xanthine replacements in drug discovery programs for a variety of biological targets. Newly designed DPP4 inhibitors achieved sub-nanomolar potency range and demonstrated oral activity in vivo in mouse glucose tolerance test.

Aminopiperidine-Fused Imidazoles as Dipeptidyl Peptidase-IV Inhibitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edmondson, S.; Mastracchio, A; Cox, J

2009-01-01

A new series of DPP-4 inhibitors derived from piperidine-fused benzimidazoles and imidazopyridines is described. Optimization of this class of DPP-4 inhibitors led to the discovery of imidazopyridine 34. The potency, selectivity, cross-species DMPK profiles, and in vivo efficacy of 34 is reported.

Synthesis, Biological Evaluation, and Molecular Docking of (R)-2-((8-(3-aminopiperidin-1-yl)-3-methyl-7-(3-methylbut-2-en-1-yl)-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-1-yl)methyl)benzonitrile as Dipeptidyl Peptidase IV Inhibitors.

PubMed

Ran, Yan; Pei, Heying; Shao, Mingfeng; Chen, Lijuan

2016-02-01

Type 2 diabetes (T2D) is classified as a major metabolic disorder, which has affected approximately 194 million people worldwide. DPP-IV inhibitors as a new therapy have shown several advantages over traditional antidiabetic drugs. Based on the similar binding modes of Alogliptin and Linagliptin, molecular operation was conducted via combining pharmacophore hybridization with structural optimization between the two market drugs and racemic compounds 40 and 43 were reported as DPP-IV inhibitors in our previous studies. But the majority of DPP-IV inhibitors have developed into a small molecule with certain conformation; in this study, we described the synthesis, biological evaluation, and molecular docking of corresponding enantiomers of compounds 40 and 43. The most potent inhibitor is (R)-40 (IC50  = 23.5 nm, F = 74.67%, T1/2  = 4 h), which exhibited moderate antihyperglycemic activity as compared to the standard antidiabetic drug Linagliptin in OGTT. In addition, compound (R)-40 effectively improved the pathological state of DIO mice. Molecular docking studies clarified the favorable binding affinity between compound (R)-40 and DPP-IV active site. Thus, compound (R)-40 would be entitled to further development as a drug candidate on the basis of the suitable pharmacokinetic (PK) and desirable pharmacodynamic (PD) profiles. © 2015 John Wiley & Sons A/S.

Dipeptidyl Peptidase-4 Inhibitor Development and Post-authorisation Programme for Vildagliptin - Clinical Evidence for Optimised Management of Chronic Diseases Beyond Type 2 Diabetes.

PubMed

Strain, William David; Paldánius, Päivi M

2017-08-01

The last decade has witnessed the role of dipeptidyl peptidase-4 (DPP-4) inhibitors in producing a conceptual change in early management of type 2 diabetes mellitus (T2DM) by shifting emphasis from a gluco-centric approach to holistically treating underlying pathophysiological processes. DPP-4 inhibitors highlighted the importance of acknowledging hypoglycaemia and weight gain as barriers to optimised care in T2DM. These complications were an integral part of diabetes management before the introduction of DPP-4 inhibitors. During the development of DPP-4 inhibitors, regulatory requirements for introducing new agents underwent substantial changes, with increased emphasis on safety. This led to the systematic collection of adjudicated cardiovascular (CV) safety data, and, where 95% confidence of a lack of harm could not be demonstrated, the standardised CV safety studies. Furthermore, the growing awareness of the worldwide extent of T2DM demanded a more diverse approach to recruitment and participation in clinical trials. Finally, the global financial crisis placed a new awareness on the health economics of diabetes, which rapidly became the most expensive disease in the world. This review encompasses unique developments in the global landscape, and the role DPP-4 inhibitors, specifically vildagliptin, have played in research advancement and optimisation of diabetes care in a diverse population with T2DM worldwide.

Dipeptidyl Peptidase-4 Inhibitor Development and Post-authorisation Programme for Vildagliptin — Clinical Evidence for Optimised Management of Chronic Diseases Beyond Type 2 Diabetes

PubMed Central

Paldánius, Päivi M

2017-01-01

Abstract The last decade has witnessed the role of dipeptidyl peptidase-4 (DPP-4) inhibitors in producing a conceptual change in early management of type 2 diabetes mellitus (T2DM) by shifting emphasis from a gluco-centric approach to holistically treating underlying pathophysiological processes. DPP-4 inhibitors highlighted the importance of acknowledging hypoglycaemia and weight gain as barriers to optimised care in T2DM. These complications were an integral part of diabetes management before the introduction of DPP-4 inhibitors. During the development of DPP-4 inhibitors, regulatory requirements for introducing new agents underwent substantial changes, with increased emphasis on safety. This led to the systematic collection of adjudicated cardiovascular (CV) safety data, and, where 95% confidence of a lack of harm could not be demonstrated, the standardised CV safety studies. Furthermore, the growing awareness of the worldwide extent of T2DM demanded a more diverse approach to recruitment and participation in clinical trials. Finally, the global financial crisis placed a new awareness on the health economics of diabetes, which rapidly became the most expensive disease in the world. This review encompasses unique developments in the global landscape, and the role DPP-4 inhibitors, specifically vildagliptin, have played in research advancement and optimisation of diabetes care in a diverse population with T2DM worldwide. PMID:29632609

DPP-4 Inhibitors: Incretin-Based Medicine for Type 2 Diabetes

MedlinePlus

... medicines? DPP-4 inhibitor medicines (generic names: sitagliptin saxagliptin, and linagliptin) are a type of incretin-based ... of diabetes medicine. Your dose of sitagliptin or saxagliptin (but not linagliptin) may need to be adjusted ...

Weight neutrality with the DPP-4 inhibitor, vildagliptin: Mechanistic basis and clinical experience

PubMed Central

Foley, James E; Jordan, Jens

2010-01-01

Various factors may confound how diabetes medications affect a patient’s weight. Agents that induce hypoglycemia may promote weight gain through “defensive eating”. Conversely, patients whose hyperglycemia exceeds the renal glucose threshold may overeat to compensate for calories lost in urine and so gain weight when drug therapy ablates glycosuria. Some drugs, such as thiazolidinediones, may promote weight gain via increased lipid storage. Glucagon-like peptide-1 receptor agonists increase satiety, delay gastric emptying, and generally produce weight loss. Dipeptidyl peptidase (DPP)-4 inhibitors are generally weight-neutral, although modest weight loss has been observed with the DPP-4 inhibitor, vildagliptin, in patients with relatively low baseline glycemia. The weight neutrality of vildagliptin likely results in part from its intrinsically low risk for hypoglycemia. Recent studies point to additional potential mechanisms. One study found that drug-naïve patients randomized to vildagliptin exhibited significantly lower chylomicron lipid and apolipoprotein levels than placebo patients, suggesting that vildagliptin may inhibit intestinal fat extraction. Another trial found that patients randomized to vildagliptin versus placebo experienced paradoxical postprandial increases in markers of fatty acid mobilization and oxidation, in conjunction with increased sympathetic stimulation. Elaboration of these and other pathways could further clarify the origins of the favorable weight profile of vildagriptin. PMID:20730070

Gemigliptin, a novel dipeptidyl peptidase 4 inhibitor: first new anti-diabetic drug in the history of Korean pharmaceutical industry.

PubMed

Kim, Sung-Ho; Lee, Sung-Hack; Yim, Hyeon-Joo

2013-10-01

Gemigliptin, a potent, selective and long-acting DPP 4 inhibitor was developed by LG Life Sciences and approved for use in patients with type 2 diabetes mellitus by the Korean Food and Drug Administration in June 2012 under the trade name Zemiglo(®). Clinical pharmacokinetic and pharmacodynamic data suggest the efficacy and once daily dosing of gemigliptin. In clinical phase III studies, gemigliptin was efficacious as either monotherapy or combination therapy (add-on to metformin) and well tolerated in patients with type 2 diabetes. Further development of combination therapy is on-going.

Short-term and long-term effects of dipeptidyl peptidase-4 inhibitors in type 2 diabetes mellitus patients with renal impairment: a meta-analysis of randomized controlled trials.

PubMed

Li, Ruifei; Wang, Rui; Li, Haixia; Sun, Sihao; Zou, Meijuan; Cheng, Gang

2016-09-01

To assess the short-term and long-term effects of dipeptidyl peptidase-4 (DPP-4) inhibitors in type 2 diabetes mellitus patients with renal impairment, a meta-analysis of randomized clinical trials of DPP-4 inhibitor interventions in type 2 diabetes mellitus patients with renal impairment was performed. PubMed, Embase, Cochrane Library and ClinicalTrials.gov were searched through the end of March 2015. Randomized clinical trials were selected if (1) DPP-4 inhibitors were compared with a placebo or other active-comparators, (2) the treatment duration was ≥12 weeks and (3) data regarding changes in haemoglobin A1c (HbA1c ), changes in fasting plasma glucose or hypoglycaemia and other adverse events were reported. Of 790 studies, ten studies on eight randomized clinical trials were included. Compared with the control group, DPP-4 inhibitors were associated with a greater HbA1c reduction in both the short-term [mean differences (MD) = -0.45, 95% confidence intervals (-0.57, -0.33), p < 0.0001] and long-term [MD = -0.33, 95% confidence intervals (-0.63, -0.03), p = 0.03] treatments. However, the long-term greater reduction in HbA1c with DPP-4 inhibitor treatment was only significant when the control treatment comprised placebo plus stable background treatment, but not glipizide plus stable background treatment. DPP-4 inhibitors were associated with a greater fasting plasma glucose reduction [MD = -12.59, 95% confidence intervals (-22.01, -3.17), p = 0.009] over the short-term; however, this effect was not present over the long-term. Regarding the hypoglycaemia adverse events assessment, the long-term treatment data indicated there was no increased risk of hypoglycaemia compared with placebo or active-controlled anti-diabetic drugs. The present meta-analysis confirms that DPP-4 inhibitors are effective and equivalent to other agents in type 2 diabetes mellitus patients with renal impairment. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Risk of hospitalization for heart failure in patients with type 2 diabetes newly treated with DPP-4 inhibitors or other oral glucose-lowering medications: a retrospective registry study on 127,555 patients from the Nationwide OsMed Health-DB Database.

PubMed

Fadini, Gian Paolo; Avogaro, Angelo; Degli Esposti, Luca; Russo, Pierluigi; Saragoni, Stefania; Buda, Stefano; Rosano, Giuseppe; Pecorelli, Sergio; Pani, Luca

2015-09-21

Oral glucose-lowering medications are associated with excess risk of heart failure (HF). Given the absence of comparative data among drug classes, we performed a retrospective study in 32 Health Services of 16 Italian regions accounting for a population of 18 million individuals, to assess the association between HF risk and use of sulphonylureas, DPP-4i, and glitazones. We extracted data on patients with type 2 diabetes who initiated treatment with DPP-4i, thiazolidinediones, or sulphonylureas alone or in combination with metformin during an accrual time of 2 years. The endpoint was hospitalization for HF (HHF) occurring after the first 6 months of therapy, and the observation was extended for up to 4 years. A total of 127 555 patients were included, of whom 14.3% were on DPP-4i, 72.5% on sulphonylurea, 13.2% on thiazolidinediones, with average 70.7% being on metformin as combination therapy. Patients in the three groups differed significantly for baseline characteristics: age, sex, Charlson index, concurrent medications, and previous cardiovascular events. During an average 2.6-year follow-up, after adjusting for measured confounders, use of DPP-4i was associated with a reduced risk of HHF compared with sulphonylureas [hazard ratio (HR) 0.78; 95% confidence interval (CI) 0.62-0.97; P = 0.026]. After propensity matching, the analysis was restricted to 39 465 patients, and the use of DPP-4i was still associated with a lower risk of HHF (HR 0.70; 95% CI 0.52-0.94; P = 0.018). In a very large observational study, the use of DPP-4i was associated with a reduced risk of HHF when compared with sulphonylureas. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Pharmacovigilance Evaluation of the Association Between DPP-4 Inhibitors and Heart Failure: Stimulated Reporting and Moderation by Drug Interactions.

PubMed

Fadini, Gian Paolo; Sarangdhar, Mayur; Avogaro, Angelo

2018-04-01

In the SAVOR-TIMI trial, the risk of heart failure (HF) was increased by 27% in T2D patients randomized to the dipeptidyl peptidase-4 inhibitor (DPP4i) saxagliptin. Other studies have provided inconsistent results regarding this association. Herein, we performed a pharmacovigilance analysis of the rate of HF associated with DPP4is, focusing on stimulated reporting and moderation by drug-drug interactions. We mined the FDA adverse event (AE) reporting system (FAERS) from 2004q1 to 2017q3, including a total of 9906,642 AE reports. Rates (/1000 reports) of HF within the reports for DPP4is and reports for other antidiabetic drugs were calculated for the period up to 2013q3 (date of publication of the SAVOR-TIMI trial results) and from 2013q4 to 2017q3. Analyses were refined by filtering according to therapeutic area, concomitant diseases and drugs, and competing AEs. The rate of HF among the AE reports filed for DPP4is significantly increased after 2013q3, especially for saxagliptin. When compared to non-insulin non-glitazone antidiabetic drugs, the proportional reporting ratio (PRR) of HF for DPP4is was 0.62 (95% CI 0.56-0.68) up to 2013q3 and 2.12 (95% CI 1.96-2.28) from 2013q4 to 2017q3. This stimulated reporting was consistent in subanalyses based on the presence/absence of cardiac disorders and after controlling for competing AEs. The rate of HF among AE reports for DPP4is was modestly moderated by the concomitant use of metformin (- 15%) and strongly moderated by the concomitant use of SGLT2 inhibitors (- 63%), even after excluding competing AEs. Within the FAERS, the association between HF and DPP4is was biased by stimulated reporting, implying that the publication of the SAVOR-TIMI trial and the subsequent regulatory warnings primed clinicians to report HF events in DPP4i users as drug-related AEs. The rate of HF associated with DPP4is was moderated when they were used in combination with SGLT2 inhibitors.

Boning up on DPP4, DPP4 substrates, and DPP4-adipokine interactions: Logical reasoning and known facts about bone related effects of DPP4 inhibitors.

PubMed

Glorie, Lorenzo; D'Haese, Patrick C; Verhulst, Anja

2016-11-01

Dipeptidyl peptidase 4 (DPP4) is a conserved exopeptidase with an important function in protein regulation. The activity of DPP4, an enzyme which can either be anchored to the plasma membrane or circulate free in the extracellular compartment, affects the glucose metabolism, cellular signaling, migration and differentiation, oxidative stress and the immune system. DPP4 is also expressed on the surface of osteoblasts, osteoclasts and osteocytes, and was found to play a role in collagen metabolism. Many substrates of DPP4 have an established role in bone metabolism, among which are incretins, gastrointestinal peptides and neuropeptides. In general, their effects favor bone formation, but some effects are complex and have not been completely elucidated. DPP4 and some of its substrates are known to interact with adipokines, playing an essential role in the energy metabolism. The prolongation of the half-life of incretins through DPP4 inhibition led to the development of these inhibitors to improve glucose tolerance in diabetes. Current literature indicates that the inhibition of DPP4 activity might also result in a beneficial effect on the bone metabolism, but the long-term effect of DPP4 inhibition on fracture outcome has not been entirely established. Diabetic as well as postmenopausal osteoporosis is associated with an increased activity of DPP4, as well as a shift in the expression levels of DPP4 substrates, their receptors, and adipokines. The interactions between these factors and their relationship in bone metabolism are therefore an interesting field of study. Copyright © 2016 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagamatsu, Shinya, E-mail: shinya@ks.kyorin-u.ac.jp; Ohara-Imaizumi, Mica; Nakamichi, Yoko

Highlights: {yields} Anti-diabetic new drug, DPP-4 inhibitor, can affect the insulin exocytosis. {yields} DPP-4 inhibitor treatment altered syntaxin 1 expression. {yields} Treatment of db/db mice with DPP-4 inhibitor increased insulin release. -- Abstract: Incretin promotes insulin secretion acutely. Recently, orally-administered DPP-4 inhibitors represent a new class of anti-hyperglycemic agents. Indeed, inhibitors of dipeptidyl peptidase-IV (DPP-4), sitagliptin, has just begun to be widely used as therapeutics for type 2 diabetes. However, the effects of sitagliptin-treatment on insulin exocytosis from single {beta}-cells are yet unknown. We therefore investigated how sitagliptin-treatment in db/db mice affects insulin exocytosis by treating db/db mice with des-F-sitagliptinmore » for 2 weeks. Perfusion studies showed that 2 weeks-sitagliptin treatment potentiated insulin secretion. We then analyzed insulin granule motion and SNARE protein, syntaxin 1, by TIRF imaging system. TIRF imaging of insulin exocytosis showed the increased number of docked insulin granules and increased fusion events from them during first-phase release. In accord with insulin exocytosis data, des-F-sitagliptin-treatment increased the number of syntaxin 1 clusters on the plasma membrane. Thus, our data demonstrated that 2-weeks des-F-sitagliptin-treatment increased the fusion events of insulin granules, probably via increased number of docked insulin granules and that of syntaxin 1 clusters.« less

Drug development from the bench to the pharmacy: with special reference to dipeptidyl peptidase-4 inhibitor development.

PubMed

Carr, R D

2016-06-01

The dipeptidyl peptidase-4 (DPP-4) inhibitor concept is an example of prospective drug design and development based upon a distinct endocrine hypothesis. The design of enzyme inhibitors is a pragmatic approach to drug design; being compatible with the identification and optimization of small molecules that have properties commensurate with oral administration, as well as acceptable drug metabolism, distribution and elimination characteristics. Glucagon-like peptide 1 (GLP-1), a hormone with a spectrum of favourable metabolic actions, including glucose-dependent stimulation of insulin and inhibition of glucagon secretion, provided the endocrine basis from which the idea of using DPP-4 inhibitors as anti-diabetic agents was developed. The origin of the DPP-4 inhibitor concept was inspired by the angiotensin-converting enzyme inhibitor approach, which succeeded in establishing a class of extensively used therapeutic agents for the treatment of cardiovascular disorders. © 2016 Diabetes UK.

Effect of Trelagliptin on Quality of Life in Patients with Type 2 Diabetes Mellitus: Study Protocol.

PubMed

Ishii, Hitoshi; Suzaki, Yuki; Miyata, Yuko

2017-12-01

Long-term glycemic control in type 2 diabetes is critical to prevent or delay the onset of macrovascular and microvascular complications. Medication adherence is an integral component of type 2 diabetes management. Minimizing the dosing frequency of antidiabetic drugs may reduce treatment burden for patients and improve medication adherence. This study has been proposed to assess the reduction in treatment burden during 12 weeks' administration of trelagliptin, a weekly dosing dipeptidyl peptidase-4 (DPP-4) inhibitor, compared with a daily dosing DPP-4 inhibitor in patients with type 2 diabetes. This is a multicenter, randomized, open-label, parallel-group, comparative study to be conducted at approximately 15 sites across Japan. A total of 240 patients are to be randomized 1:1 to receive trelagliptin or a daily DPP-4 inhibitor for 12 weeks. Efficacy and safety will be compared between the two groups. The primary endpoint is the change in total score for all items of the diabetes-therapy-related QOL questionnaire from treatment start to treatment end. The study will be conducted with the highest respect for the individual participants in accordance with the protocol, the Declaration of Helsinki, the Ethical Guidelines for Clinical Research, the ICH Consolidated Guideline for Good Clinical Practice, and applicable local laws and regulations. Takeda Pharmaceutical Company Limited. Japic CTI-173482.

Cardiovascular Biology of the Incretin System

PubMed Central

Ussher, John R.; Drucker, Daniel J.

2012-01-01

Glucagon-like peptide-1 (GLP-1) is an incretin hormone that enhances glucose-stimulated insulin secretion and exerts direct and indirect actions on the cardiovascular system. GLP-1 and its related incretin hormone, glucose-dependent insulinotropic polypeptide (GIP), are rapidly inactivated by the enzyme dipeptidyl peptidase 4 (DPP-4), a key determinant of incretin bioactivity. Two classes of medications that enhance incretin action, GLP-1R agonists and DPP-4 inhibitors, are used for the treatment of type 2 diabetes mellitus (T2DM). We review herein the cardiovascular biology of GLP-1R agonists and DPP-4 inhibitors, including direct and indirect effects on cardiomyocytes, blood vessels, adipocytes, the control of blood pressure and postprandial lipoprotein secretion. Both GLP-1R activation and DPP-4 inhibition exert multiple cardioprotective actions in preclinical models of cardiovascular dysfunction, and short term studies in human subjects appear to demonstrate modest yet beneficial actions on cardiac function in subjects with ischemic heart disease. Incretin-based agents control body weight, improve glycemic control with a low risk of hypoglycemia, decrease blood pressure, inhibit the secretion of intestinal chylomicrons, and reduce inflammation in preclinical studies. Nevertheless, there is limited information on the cardiovascular actions of these agents in patients with diabetes and established cardiovascular disease. Hence, a more complete understanding of the cardiovascular risk:benefit ratio of incretin-based therapies will require completion of long term cardiovascular outcome studies currently underway in patients with T2DM. PMID:22323472

Effects of vildagliptin as add-on treatment in patients with type 2 diabetes mellitus: insights from long-term clinical studies in Japan.

PubMed

Odawara, Masato; Sagara, Rieko

2015-01-01

Vildagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, is wildly used to treat type 2 diabetes mellitus (T2DM) with mono- or combination-therapy. We review two previously published open-label studies to extract insights on the long-term efficacy and safety of vildagliptin. Two studies were conducted in Japan to assess the efficacy and safety of vildagliptin as an add-on to other oral antidiabetes drugs (OADs) for 52 weeks. These studies were performed under the similar protocol in Japanese patients with T2DM who were inadequately controlled with OAD monotherapy [excluding other dipeptidyl peptidase-4 (DPP-4) inhibitors]. Addition of vildagliptin (50 mg twice daily) to other OAD monotherapy [sulfonylurea (SU), metformin, thiazolidinedione, alpha-glucosidase inhibitor and glinide] reduced glycated hemoglobin (HbA1c) levels by -0.64 %,-0.75 %,-0.92 %,-0.94 % and - 0.64 %, respectively, over 52 weeks of treatment. Overall, the incidence of hypoglycemia was low and was slightly higher in the add-on to SU treatment group compared with the other groups. The incidences of adverse events were comparable among the treatment groups, and vildagliptin was well-tolerated as add-on therapy to other OADs. The evidence from the two studies indicates that vildagliptin as an add-on therapy to other OADs is a clinically reasonable option for Japanese patients with T2DM who respond inadequately to other OAD monotherapy.

Dipeptidyl peptidase-4 inhibitors or sodium glucose co-transporter-2 inhibitors as an add-on to insulin therapy: A comparative review

PubMed Central

Singh, Awadhesh Kumar; Singh, Ritu

2016-01-01

The gradual decline in β-cell function is inevitable in type 2 diabetes mellitus and therefore, substantial proportions of patients require insulin subsequently, in order to achieve optimal glucose control. While weight gain, hypoglycemia, and fluid retention especially during dose intensification is a known limitation to insulin therapy, these adverse effects also reduce patient satisfaction and treatment adherence. It is also possible that the benefits of intensive control achieved by insulin therapy, perhaps get nullified by the weight gain and hypoglycemia. In addition, improvement in plasma glucose or glycated hemoglobin (HbA1c) itself is associated with weight gain. Notably, studies have already suggested that reduction in body weight by ~3–5%, may allow a significantly better glycemic control. Thus, a class of drugs, which can reduce HbA1c effectively, yet are weight neutral or preferably reduce body weight, could be the most sought out strategy as an add-on therapy to insulin. While sulfonylureas (SUs) are associated with weight gain and hypoglycemia, pioglitazone increases body weight and fluid retention. Moreover, SUs are not recommended once premix or prandial insulin is commenced. The addition of newer agents, such as glucagon-like peptide-1 receptor agonist to insulin certainly appears to be an effective tool in reducing both HbA1c and body weight as is evident across the studies; however, this approach incurs an additional injection as well as cost. Dipeptidyl peptidase-4 inhibitors (DPP-4I) and sodium-glucose co-transporter-2 inhibitors (SGLT-2I) are other exciting options, as an add-on to insulin therapy primarily because these are oral drugs and do not possess any intrinsic potential of hypoglycemia. Furthermore, these are either weight neutral or induce significant weight loss. This review article aims to comparatively analyze the safety and efficacy of DPP-4I and SGLT-2I, as an add-on therapy to insulin. PMID:26904466

Incretin-based therapies in the management of type 2 diabetes: rationale and reality in a managed care setting.

PubMed

Garber, Alan J

2010-08-01

In addition to the hypoglycemia and weight gain associated with many treatments for type 2 diabetes, alpha-glucosidase inhibitors, thiazolidinediones, metformin, sulfonylureas, and the glinides do not address all of the multiple defects existing in the pathophysiology of the disease. Cumulatively, these oral agents address the influx of glucose from the gastrointestinal tract, impaired insulin activity, and acute beta-cell dysfunction in type 2 diabetes; however, until recently, there were no means to deal with the inappropriate hyperglucagonemia or chronic beta-cell-decline characteristic of the disease. The recently introduced incretin-based therapies serve to address some of the challenges associated with traditionally available oral antidiabetic agents. In addition to improving beta-cell function, stimulating insulin secretion, and inhibiting glucagon secretion, these agents reduce appetite, thereby stabilizing weight and/or promoting weight loss in patients with type 2 diabetes. Of the incretin-based therapies, both the dipeptidyl peptidase-4 (DPP-4) inhibitors and the glucagon-like peptide-1 (GLP-1) receptor agonists stimulate insulin secretion and inhibit glucagon secretion. The subsequent review outlines evidence from selected clinical trials of the currently available GLP-1 receptor agonists, exenatide and liraglutide, and DPP-4 inhibitors, sitagliptin and saxagliptin. Earlier and more frequent use of these incretin-based therapies is recommended in the treatment of type 2 diabetes, based on their overall safety and ability to achieve the glycosylated hemoglobin level goal. As such, both the American Diabetes Association and the American Association of Clinical Endocrinologists/American College of Endocrinology (AACE/ACE) treatment algorithms recommend the use of incretin-based therapy in both treatment-naive and previously treated patients. The AACE/ACE guidelines clearly state that these agents should not be limited to third- or fourth-line therapy.

Cost-effectiveness of dipeptidyl peptidase-4 inhibitor monotherapy versus sulfonylurea monotherapy for people with type 2 diabetes and chronic kidney disease in Thailand.

PubMed

Permsuwan, Unchalee; Dilokthornsakul, Piyameth; Thavorn, Kednapa; Saokaew, Surasak; Chaiyakunapruk, Nathorn

2017-02-01

With a high prevalence of chronic kidney disease (CKD) in type 2 diabetes (T2DM) in Thailand, the appropriate treatment for the patients has become a major concern. This study aimed to evaluate long-term cost-effective of dipeptidyl peptidase-4 (DPP-4) inhibitor monothearpy vs sulfonylurea (SFU) monotherapy in people with T2DM and CKD. A validated IMS CORE Diabetes Model was used to estimate the long-term costs and outcomes. The efficacy parameters were identified and synthesized using a systematic review and meta-analysis. Baseline characteristics and cost parameters were obtained from published studies and hospital databases in Thailand. Costs were expressed in 2014 US Dollars. Outcomes were presented as an incremental cost-effectiveness ratio (ICER). One-way and probabilistic sensitivity analyses were performed to estimate parameter uncertainty. From a societal perspective, treatment with DPP-4 inhibitors yielded more quality-adjusted life years (QALYs) (0.024) at a higher cost (>66,000 Thai baht (THB) or >1,829.27 USD) per person than SFU, resulting in the ICER of >2.7 million THB/QALY (>74,833.70 USD/QALY). The cost-effectiveness results were mainly driven by differences in HbA1c reduction, hypoglycemic events, and drug acquisition cost of DPP-4 inhibitors. At the ceiling ratio of 160,000 THB/QALY (4,434.59 USD/QALY), the probability that DPP-4 inhibitors are cost-effective compared to SFU was less than 10%. Compared to SFU, DPP-4 inhibitor monotherapy is not a cost-effective treatment for people with T2DM and CKD in Thailand.

Hypoglycemia hospitalization frequency in patients with type 2 diabetes mellitus: a comparison of dipeptidyl peptidase 4 inhibitors and insulin secretagogues using the French health insurance database.

PubMed

Detournay, Bruno; Halimi, Serge; Robert, Julien; Deschaseaux, Céline; Dejager, Sylvie

2015-01-01

We aimed to compare the frequency of severe hypoglycemia leading to hospitalization (HH) and emergency visits (EV) for any cause in patients with type 2 diabetes mellitus exposed to dipeptidyl peptidase 4 (DPP4) inhibitors (DPP4-i) versus those exposed to insulin secretagogues (IS; sulfonylureas or glinides). Data were extracted from the EGB (Echantillon Généraliste des Bénéficiaires) database, comprising a representative sample of ~1% of patients registered in the French National Health Insurance System (~600,000 patients). Type 2 diabetes mellitus patients exposed to regimens containing either a DPP4-i (excluding treatment with IS, insulin, or glucagon-like peptide 1 analog) or IS (excluding treatment with insulin and any incretin therapy) between 2009 and 2012 were selected. HH and EV during the exposure periods were identified in both cohorts. A similar analysis was conducted considering vildagliptin alone versus IS. Comparative analyses adjusting for covariates within the model (subjects matched for key characteristics) and using multinomial regression models were performed. Overall, 7,152 patients exposed to any DPP4-i and 1,440 patients exposed to vildagliptin were compared to 10,019 patients exposed to IS. Eight patients (0.11%) from the DPP4-i cohort and none from the vildagliptin cohort (0.0%) were hospitalized for hypoglycemia versus 130 patients (1.30%) from the IS cohort (138 hospitalizations) (P=0.02 and P<0.0001, respectively). Crude rates of HH/1,000 patient-years were 1.4 (95% CI: 0.7; 2.4) in the DPP4-i cohort, 0.0 in the vildagliptin cohort (95% CI: 0.0; 4.0), versus 5.6 (95% CI, 4.7; 6.6) in the IS cohort (P<0.0001). After adjustments, rates per 1,000 patient-years of HH were 1.4 (95% CI: 0.7; 2.4) with DPP4-i versus 7.5 (95% CI: 6.0; 9.2) with IS (P<0.0001), and 0.0 (95% CI: 0.0; 4.0) with vildagliptin versus 13.6 (95% CI: 10.4; 17.5) with IS (P<0.0001). Adjusted EV rates were also significantly lower with all DPP4-i or with vildagliptin, as compared to IS (P<0.0001). Consistent results were found when considering only treatment initiations for all compared cohorts. HH and EV were significantly less frequent in patients exposed to any DPP4-i or to vildagliptin versus IS. These real-life data should be considered in the benefit/risk evaluation of the drugs.

Hypoglycemia hospitalization frequency in patients with type 2 diabetes mellitus: a comparison of dipeptidyl peptidase 4 inhibitors and insulin secretagogues using the French health insurance database

PubMed Central

Detournay, Bruno; Halimi, Serge; Robert, Julien; Deschaseaux, Céline; Dejager, Sylvie

2015-01-01

Aim We aimed to compare the frequency of severe hypoglycemia leading to hospitalization (HH) and emergency visits (EV) for any cause in patients with type 2 diabetes mellitus exposed to dipeptidyl peptidase 4 (DPP4) inhibitors (DPP4-i) versus those exposed to insulin secretagogues (IS; sulfonylureas or glinides). Methods Data were extracted from the EGB (Echantillon Généraliste des Bénéficiaires) database, comprising a representative sample of ~1% of patients registered in the French National Health Insurance System (~600,000 patients). Type 2 diabetes mellitus patients exposed to regimens containing either a DPP4-i (excluding treatment with IS, insulin, or glucagon-like peptide 1 analog) or IS (excluding treatment with insulin and any incretin therapy) between 2009 and 2012 were selected. HH and EV during the exposure periods were identified in both cohorts. A similar analysis was conducted considering vildagliptin alone versus IS. Comparative analyses adjusting for covariates within the model (subjects matched for key characteristics) and using multinomial regression models were performed. Results Overall, 7,152 patients exposed to any DPP4-i and 1,440 patients exposed to vildagliptin were compared to 10,019 patients exposed to IS. Eight patients (0.11%) from the DPP4-i cohort and none from the vildagliptin cohort (0.0%) were hospitalized for hypoglycemia versus 130 patients (1.30%) from the IS cohort (138 hospitalizations) (P=0.02 and P<0.0001, respectively). Crude rates of HH/1,000 patient-years were 1.4 (95% CI: 0.7; 2.4) in the DPP4-i cohort, 0.0 in the vildagliptin cohort (95% CI: 0.0; 4.0), versus 5.6 (95% CI, 4.7; 6.6) in the IS cohort (P<0.0001). After adjustments, rates per 1,000 patient-years of HH were 1.4 (95% CI: 0.7; 2.4) with DPP4-i versus 7.5 (95% CI: 6.0; 9.2) with IS (P<0.0001), and 0.0 (95% CI: 0.0; 4.0) with vildagliptin versus 13.6 (95% CI: 10.4; 17.5) with IS (P<0.0001). Adjusted EV rates were also significantly lower with all DPP4-i or with vildagliptin, as compared to IS (P<0.0001). Consistent results were found when considering only treatment initiations for all compared cohorts. Conclusion HH and EV were significantly less frequent in patients exposed to any DPP4-i or to vildagliptin versus IS. These real-life data should be considered in the benefit/risk evaluation of the drugs. PMID:26229480

Structures and mechanism of dipeptidyl peptidases 8 and 9, important players in cellular homeostasis and cancer.

PubMed

Ross, Breyan; Krapp, Stephan; Augustin, Martin; Kierfersauer, Reiner; Arciniega, Marcelino; Geiss-Friedlander, Ruth; Huber, Robert

2018-02-13

Dipeptidyl peptidases 8 and 9 are intracellular N-terminal dipeptidyl peptidases (preferentially postproline) associated with pathophysiological roles in immune response and cancer biology. While the DPP family member DPP4 is extensively characterized in molecular terms as a validated therapeutic target of type II diabetes, experimental 3D structures and ligand-/substrate-binding modes of DPP8 and DPP9 have not been reported. In this study we describe crystal and molecular structures of human DPP8 (2.5 Å) and DPP9 (3.0 Å) unliganded and complexed with a noncanonical substrate and a small molecule inhibitor, respectively. Similar to DPP4, DPP8 and DPP9 molecules consist of one β-propeller and α/β hydrolase domain, forming a functional homodimer. However, they differ extensively in the ligand binding site structure. In intriguing contrast to DPP4, where liganded and unliganded forms are closely similar, ligand binding to DPP8/9 induces an extensive rearrangement at the active site through a disorder-order transition of a 26-residue loop segment, which partially folds into an α-helix (R-helix), including R160/133, a key residue for substrate binding. As vestiges of this helix are also seen in one of the copies of the unliganded form, conformational selection may contributes to ligand binding. Molecular dynamics simulations support increased flexibility of the R-helix in the unliganded state. Consistently, enzyme kinetics assays reveal a cooperative allosteric mechanism. DPP8 and DPP9 are closely similar and display few opportunities for targeted ligand design. However, extensive differences from DPP4 provide multiple cues for specific inhibitor design and development of the DPP family members as therapeutic targets or antitargets.

Predicting DPP-IV inhibitors with machine learning approaches

NASA Astrophysics Data System (ADS)

Cai, Jie; Li, Chanjuan; Liu, Zhihong; Du, Jiewen; Ye, Jiming; Gu, Qiong; Xu, Jun

2017-04-01

Dipeptidyl peptidase IV (DPP-IV) is a promising Type 2 diabetes mellitus (T2DM) drug target. DPP-IV inhibitors prolong the action of glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP), improve glucose homeostasis without weight gain, edema, and hypoglycemia. However, the marketed DPP-IV inhibitors have adverse effects such as nasopharyngitis, headache, nausea, hypersensitivity, skin reactions and pancreatitis. Therefore, it is still expected for novel DPP-IV inhibitors with minimal adverse effects. The scaffolds of existing DPP-IV inhibitors are structurally diversified. This makes it difficult to build virtual screening models based upon the known DPP-IV inhibitor libraries using conventional QSAR approaches. In this paper, we report a new strategy to predict DPP-IV inhibitors with machine learning approaches involving naïve Bayesian (NB) and recursive partitioning (RP) methods. We built 247 machine learning models based on 1307 known DPP-IV inhibitors with optimized molecular properties and topological fingerprints as descriptors. The overall predictive accuracies of the optimized models were greater than 80%. An external test set, composed of 65 recently reported compounds, was employed to validate the optimized models. The results demonstrated that both NB and RP models have a good predictive ability based on different combinations of descriptors. Twenty "good" and twenty "bad" structural fragments for DPP-IV inhibitors can also be derived from these models for inspiring the new DPP-IV inhibitor scaffold design.

Glucose-independent renoprotective mechanisms of the tissue dipeptidyl peptidase-4 inhibitor, saxagliptin, in Dahl salt-sensitive hypertensive rats.

PubMed

Uchii, Masako; Kimoto, Naoya; Sakai, Mariko; Kitayama, Tetsuya; Kunori, Shunji

2016-07-15

Although previous studies have shown an important role of renal dipeptidyl peptidase-4 (DPP-4) inhibition in ameliorating kidney injury in hypertensive rats, the renal distribution of DPP-4 and mechanisms of renoprotective action of DPP-4 inhibition remain unclear. In this study, we examined the effects of the DPP-4 inhibitor saxagliptin on DPP-4 activity in renal cells (using in situ DPP-4 staining) and on renal gene expression related to inflammation and fibrosis in the renal injury in hypertensive Dahl salt-sensitive (Dahl-S) rats. Male rats fed a high-salt (8% NaCl) diet received vehicle (water) or saxagliptin (12.7mg/kg/day) for 4 weeks. Blood pressure (BP), serum glucose and 24-h urinary albumin and sodium excretions were measured, and renal histopathology was performed. High salt-diet increased BP and urinary albumin excretion, consequently resulting in glomerular sclerosis and tubulointerstitial fibrosis. Although saxagliptin did not affect BP and blood glucose levels, it significantly ameliorated urinary albumin excretion. In situ staining showed DPP-4 activity in glomerular and tubular cells. Saxagliptin significantly suppressed DPP-4 activity in renal tissue extracts and in glomerular and tubular cells. Saxagliptin also significantly attenuated the increase in inflammation and fibrosis-related gene expressions in the kidney. Our results demonstrate that saxagliptin inhibited the development of renal injury independent of its glucose-lowering effect. Glomerular and tubular DPP-4 inhibition by saxagliptin was associated with improvements in albuminuria and the suppression of inflammation and fibrosis-related genes. Thus, local glomerular and tubular DPP-4 inhibition by saxagliptin may play an important role in its renoprotective effects in Dahl-S rats. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Cut to the chase: a review of CD26/dipeptidyl peptidase‐4's (DPP4) entanglement in the immune system

PubMed Central

Wagner, L.; Stephan, M.; von Hörsten, S.

2016-01-01

Summary CD26/DPP4 (dipeptidyl peptidase 4/DP4/DPPIV) is a surface T cell activation antigen and has been shown to have DPP4 enzymatic activity, cleaving‐off amino‐terminal dipeptides with either L‐proline or L‐alanine at the penultimate position. It plays a major role in glucose metabolism by N‐terminal truncation and inactivation of the incretins glucagon‐like peptide‐1 (GLP) and gastric inhibitory protein (GIP). In 2006, DPP4 inhibitors have been introduced to clinics and have been demonstrated to efficiently enhance the endogenous insulin secretion via prolongation of the half‐life of GLP‐1 and GIP in patients. However, a large number of studies demonstrate clearly that CD26/DPP4 also plays an integral role in the immune system, particularly in T cell activation. Therefore, inhibition of DPP4 might represent a double‐edged sword. Apart from the metabolic benefit, the associated immunological effects of long term DPP4 inhibition on regulatory processes such as T cell homeostasis, maturation and activation are not understood fully at this stage. The current data point to an important role for CD26/DPP4 in maintaining lymphocyte composition and function, T cell activation and co‐stimulation, memory T cell generation and thymic emigration patterns during immune‐senescence. In rodents, critical immune changes occur at baseline levels as well as after in‐vitro and in‐vivo challenge. In patients receiving DPP4 inhibitors, evidence of immunological side effects also became apparent. The scope of this review is to recapitulate the role of CD26/DPP4 in the immune system regarding its pharmacological inhibition and T cell‐dependent immune regulation. PMID:26919392

Identification and characterization of a dipeptidyl peptidase IV inhibitor from aronia juice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozuka, Miyuki; Yamane, Takuya, E-mail: t-yamane@pharm.hokudai.ac.jp; Nakano, Yoshihisa

Aronia berries have many potential effects on health, including an antioxidant effect, effect for antimutagenesis, hepatoprotection and cardioprotection, an antidiabetic effect and inhibition of cancer cell proliferation. Previous human studies have shown that aronia juice may be useful for treatment of obesity disorders. In this study, we found that aronia juice has an inhibitory effect against dipeptidyl peptidase IV (DPP IV) (EC 3.4.14.5). DPP IV is a peptidase that cleaves the N-terminal region of incretins such as glucagon-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). Inactivation of incretins by DPP IV induces reduction of insulin secretion. Furthermore, we identified thatmore » cyanidin 3, 5-diglucoside as the DPP IV inhibitor in aronia juice. DPP IV was inhibited more strongly by cyanidin 3, 5-diglucoside than by cyanidin and cyanidin 3-glucoside. The results suggest that DPP IV is inhibited by cyanidin 3, 5-diglucoside present in aronia juice. The antidiabetic effect of aronia juice may be mediated through DPP IV inhibition by cyanidin 3, 5-diglucoside. - Highlights: • DPP IV activity is inhibited by aronia juice. • DPP IV inhibitor is cyanidin 3, 5-diglucoside in aronia juice. • DPP IV is inhibited by cyanidin 3, 5-diglucoside more than cyanidin and cyanidin 3-glucoside.« less

Time Trends and Geographical Variation in Prescribing of Drugs for Diabetes in England 1998-2017.

PubMed

Curtis, Helen J; Dennis, John M; Shields, Beverley M; Walker, Alex J; Bacon, Seb; Hattersley, Andrew T; Jones, Angus G; Goldacre, Ben

2018-05-07

UK guidelines for type II diabetes leave the choice of glucose lowering therapies after metformin largely to prescribers. They vary greatly in cost, and comparative effectiveness data is lacking. We set out to measure the variation in prescribing of these second-line non-insulin diabetes drugs. We evaluated time trends 1998-2016, using England's publicly available prescribing datasets, and stratified by the order prescribed to patients using the Clinical Practice Research Datalink (CPRD). We calculated the proportion of each class of diabetes drug as a percentage of the total per year. We evaluated geographical variation in prescribing using general practice-level data for the latest 12-months (to August 2017), with aggregation to Clinical Commissioning Groups (CCGs). We calculated percentiles, ranges and plotted maps. Prescribing of therapy after metformin is changing rapidly. DPP4-inhibitor use has increased markedly, now the most common second-line drug (43% prescriptions in 2016). Use of SGLT-2 inhibitors also increased rapidly (14% new second-line, 27% new third-line prescriptions in 2016). There is wide geographical variation in choice of therapies and average spend per patient. In contrast, metformin is consistently used first-line in accordance with guidelines. In England there is extensive geographical variation in the prescribing of diabetes drugs after metformin, and increasing use of higher-cost DPP4-inhibitors and SGLT-2 inhibitors over low-cost sulfonylureas. Our findings strongly support the case for comparative effectiveness trials of current diabetes drugs. This article is protected by copyright. All rights reserved.

Experience with DPP-4 inhibitors in the management of patients with type 2 diabetes fasting during Ramadan

PubMed Central

Schweizer, Anja; Halimi, Serge; Dejager, Sylvie

2014-01-01

A large proportion of Muslim patients with type 2 diabetes mellitus (T2DM) elect to fast during the holy month of Ramadan. For these patients hypo- and hyperglycemia constitute two major complications associated with the profound changes in food pattern during the Ramadan fast, and efficacious treatment options with a low risk of hypoglycemia are therefore needed to manage their T2DM as effectively and safely as possible. Dipeptidyl peptidase-4 (DPP-4) inhibitors modulate insulin and glucagon secretion in a glucose-dependent manner, and consequently a low propensity of hypoglycemia has consistently been reported across different patient populations with these agents. Promising data with DPP-4 inhibitors have now also started to emerge in patients with T2DM fasting during Ramadan. The objective of this review is to provide a comprehensive overview of the currently available evidence and potential role of DPP-4 inhibitors in the management of patients with T2DM fasting during Ramadan whose diabetes is treated with oral antidiabetic drugs, and to discuss the mechanistic basis for their beneficial effects in this setting. PMID:24391442

In vivo dual-delivery of glucagon like peptide-1 (GLP-1) and dipeptidyl peptidase-4 (DPP4) inhibitor through composites prepared by microfluidics for diabetes therapy

NASA Astrophysics Data System (ADS)

Araújo, F.; Shrestha, N.; Gomes, M. J.; Herranz-Blanco, B.; Liu, D.; Hirvonen, J. J.; Granja, P. L.; Santos, H. A.; Sarmento, B.

2016-05-01

Oral delivery of proteins is still a challenge in the pharmaceutical field. Nanoparticles are among the most promising carrier systems for the oral delivery of proteins by increasing their oral bioavailability. However, most of the existent data regarding nanosystems for oral protein delivery is from in vitro studies, lacking in vivo experiments to evaluate the efficacy of these systems. Herein, a multifunctional composite system, tailored by droplet microfluidics, was used for dual delivery of glucagon like peptide-1 (GLP-1) and dipeptidyl peptidase-4 inhibitor (iDPP4) in vivo. Oral delivery of GLP-1 with nano- or micro-systems has been studied before, but the simultaneous nanodelivery of GLP-1 with iDPP4 is a novel strategy presented here. The type 2 diabetes mellitus (T2DM) rat model, induced through the combined administration of streptozotocin and nicotinamide, a non-obese model of T2DM, was used. The combination of both drugs resulted in an increase in the hypoglycemic effects in a sustained, but prolonged manner, where the iDPP4 improved the therapeutic efficacy of GLP-1. Four hours after the oral administration of the system, blood glucose levels were decreased by 44%, and were constant for another 4 h, representing half of the glucose area under the curve when compared to the control. An enhancement of the plasmatic insulin levels was also observed 6 h after the oral administration of the dual-drug composite system and, although no statistically significant differences existed, the amount of pancreatic insulin was also higher. These are promising results for the oral delivery of GLP-1 to be pursued further in a chronic diabetic model study.

Comparison of efficacies of a dipeptidyl peptidase IV inhibitor and alpha-glucosidase inhibitors in oral carbohydrate and meal tolerance tests and the effects of their combination in mice.

PubMed

Yamazaki, Kazuto; Inoue, Takashi; Yasuda, Nobuyuki; Sato, Yoshiaki; Nagakura, Tadashi; Takenaka, Osamu; Clark, Richard; Saeki, Takao; Tanaka, Isao

2007-05-01

E3024 (3-but-2-ynyl-5-methyl-2-piperazin-1-yl-3,5-dihydro-4H-imidazo[4,5-d]pyridazin-4-one tosylate) is a dipeptidyl peptidase IV (DPP-IV) inhibitor. Since the target of both DPP-IV inhibitors and alpha-glucosidase inhibitors is the lowering of postprandial hyperglycemia, we compared antihyperglycemic effects for E3024 and alpha-glucosidase inhibitors in various oral carbohydrate and meal tolerance tests using normal mice. In addition, we investigated the combination effects of E3024 and voglibose on blood glucose levels in a meal tolerance test using mice fed a high-fat diet. ER-235516-15 (the trifluoroacetate salt form of E3024, 1 mg/kg) lowered glucose excursions consistently, regardless of the kind of carbohydrate loaded. However, the efficacy of acarbose (10 mg/kg) and of voglibose (0.1 mg/kg) varied with the type of carbohydrate administered. The combination of E3024 (3 mg/kg) and voglibose (0.3 mg/kg) improved glucose tolerance additively, with the highest plasma active glucagon-like peptide-1 levels. This study shows that compared to alpha-glucosidase inhibitors, DPP-IV inhibitors may have more consistent efficacy to reduce postprandial hyperglycemia, independent of the types of carbohydrate contained in a meal, and that the combination of a DPP-IV inhibitor and an alpha-glucosidase inhibitor is expected to be a promising option for lowering postprandial hyperglycemia.

Utility of Saxagliptin in the Treatment of Type 2 Diabetes: Review of Efficacy and Safety.

PubMed

Jain, Rajeev

2015-11-01

Type 2 diabetes mellitus (T2DM) is a complex disease in which multiple organs and hormones contribute to the pathogenesis of disease. The intestinal hormone, glucagon-like peptide-1 (GLP-1), secreted in response to nutrient ingestion, increases insulin secretion from pancreatic β-cells and reduces glucagon secretion from pancreatic α-cells. GLP-1 is inactivated by the dipeptidyl peptidase-4 (DPP-4) enzyme. Saxagliptin is a DPP-4 inhibitor that prevents the degradation of endogenous GLP-1 and prolongs its actions on insulin and glucagon secretion. This article reviews the efficacy and safety of saxagliptin in patients with T2DM. A PubMed literature search was conducted to identify relevant, peer-reviewed saxagliptin clinical trial articles published between January 2008 and June 2015. Search terms included "saxagliptin" and "DPP-4 inhibitors". In clinical trials, saxagliptin significantly improved glycemic control when used as monotherapy or as add-on therapy to other antidiabetes agents and was associated with a low risk of hypoglycemia. In a large cardiovascular (CV) outcomes trial (SAVOR) in patients with T2DM and with established CV disease or multiple CV risk factors, saxagliptin neither increased nor decreased CV risk compared with placebo as assessed by the composite end point of death from CV causes, nonfatal myocardial infarction, or nonfatal stroke. Unexpectedly, more patients in the saxagliptin (3.5%) than in the placebo group (2.8%) were hospitalized for heart failure. Saxagliptin demonstrated statistically significant and clinically meaningful improvements in glycemic control and a low risk of hypoglycemia in patients with T2DM. However, this positive profile needs to be tempered by the observation of an increased risk of hospitalization for heart failure in the SAVOR trial. Results from ongoing CV outcome trials with other DPP-4 inhibitors may provide additional data on how best to manage patients with T2DM who are at risk for heart failure. AstraZeneca LP.

Effects of linagliptin on human immortalized podocytes: a cellular system to study dipeptidyl‐peptidase 4 inhibition

PubMed Central

Miglio, Gianluca; Vitarelli, Giovanna; Klein, Thomas

2017-01-01

Background and Purpose Dipeptidyl‐peptidase 4 (DPP4) is expressed by resident renal cells, including glomerular cells. DPP4 inhibitors (gliptins) exert albuminuria lowering effects, but the role of renal DPP4 as a pharmacological target has not been elucidated. To better understand the actions of gliptins, the effects of linagliptin on the behaviour of immortalized human podocytes and mesangial cells were evaluated. Experimental Approach The expression of DPP4 was measured at both the mRNA and protein levels. The effects of linagliptin on DPP4 activity, cell growth and cell cycle progression were determined. The contribution of the stromal cell‐derived factor‐1‐ CXCR4/CXCR7 signalling pathways was evaluated by studying the effects of AMD3100 (a CXCR4 antagonist and CXCR7 agonist) alone and in combination with linagliptin. The contribution of ERK1/2 activation was analysed by studying the effects of the MAPK kinase 1/2 inhibitor AZD6244. Key Results DPP4 was highly expressed in podocytes. The activity of DPP4 and podocyte growth were reduced by linagliptin. The effects of sitagliptin on podocyte growth were similar to those of linagliptin, were associated with inhibition of cell proliferation and mimicked by AMD3100. Moreover, linagliptin and AMD3100 were found to have a synergistic interaction, whereas no interaction was seen between linagliptin and AZD6244. Conclusions and Implications Our cultures of human glomerular cells represent a reliable system for investigating the actions of gliptins. Moreover, DPP4 contributes to the regulation of podocyte behaviour. Inhibition of DPP4 in podocytes could underlie the effects of linagliptin on glomerular cells. PMID:28177527

Critical role of renal dipeptidyl peptidase-4 in ameliorating kidney injury induced by saxagliptin in Dahl salt-sensitive hypertensive rats.

PubMed

Sakai, Mariko; Uchii, Masako; Myojo, Kensuke; Kitayama, Tetsuya; Kunori, Shunji

2015-08-15

Saxagliptin, a potent dipeptidyl peptidase-4 (DPP-4) inhibitor, is currently used to treat type 2 diabetes mellitus, and it has been reported to exhibit a slower rate of dissociation from DPP-4 compared with another DPP-4 inhibitor, sitagliptin. In this study, we compared the effects of saxagliptin and sitagliptin on hypertension-related renal injury and the plasma and renal DPP-4 activity levels in Dahl salt-sensitive hypertensive (Dahl-S) rats. The high-salt diet (8% NaCl) significantly increased the blood pressure and quantity of urinary albumin excretion and induced renal glomerular injury in the Dahl-S rats. Treatment with saxagliptin (14mg/kg/day via drinking water) for 4 weeks significantly suppressed the increase in urinary albumin excretion and tended to ameliorate glomerular injury without altering the blood glucose levels and systolic blood pressure. On the other hand, the administration of sitagliptin (140mg/kg/day via drinking water) did not affect urinary albumin excretion and glomerular injury in the Dahl-S rats. Meanwhile, the high-salt diet increased the renal DPP-4 activity but did not affect the plasma DPP-4 activity in the Dahl-S rats. Both saxagliptin and sitagliptin suppressed the plasma DPP-4 activity by 95% or more. Although the renal DPP-4 activity was also inhibited by both drugs, the inhibitory effect of saxagliptin was more potent than that of sitagliptin. These results indicate that saxagliptin has a potent renoprotective effect in the Dahl-S rats, independent of its glucose-lowering actions. The inhibition of the renal DPP-4 activity induced by saxagliptin may contribute to ameliorating renal injury in hypertension-related renal injury. Copyright © 2015 Elsevier B.V. All rights reserved.

Hemoglobin glycation index as a useful predictor of therapeutic responses to dipeptidyl peptidase-4 inhibitors in patients with type 2 diabetes

PubMed Central

Chen, Yu-Wei; Wang, Jun-Sing; Sheu, Wayne H-H; Lin, Shih-Yi; Lee, I-Te; Song, Yuh-Min; Fu, Chia-Po; Lee, Chia-Lin

2017-01-01

Introduction A high hemoglobin glycation index (HGI) and glycated hemoglobin (HbA1c) level are associated with greater inflammatory status, and dipeptidyl peptidase-4 (DPP-4) inhibitors can suppress inflammation. We aimed to evaluate the relationship between HGI and the therapeutic effect of DPP-4 inhibitors. Methods This retrospective cohort study followed 468 patients with type 2 diabetes receiving DPP-4 inhibitor treatment for 1 year. Estimated HbA1c was calculated using a linear regression equation derived from another 2969 randomly extracted patients with type 2 diabetes based on fasting plasma glucose (FPG) level. The subjects were divided into two groups based on HGI (HGI = observed HbA1c - estimated HbA1c). Mixed model repeated measures were used to compare the treatment efficacy after 1 year in patients with a low (HGI<0, n = 199) and high HGI (HGI≧0, n = 269). Results There were no significant group differences in mean changes of FPG after 1 year (-12.8 and -13.4 mg/dL in the low and high HGI groups, respectively). However, the patients with a high HGI had a significantly greater reduction in HbA1c from baseline compared to those with a low HGI (-1.9 versus -0.3% [-20.8 versus -3.3 mmol/mol]). Improvements in glycemic control were statistically significantly associated with the tested DPP-4 inhibitors in the high HGI group (-2.4, -1.4, -1.2 and -2.2% [-26.2, -15.3, -13.1 and -24.0 mmol/mol] for vildagliptin, linagliptin, saxagliptin and sitagliptin, respectively) but not in the low HGI group. Conclusions The HGI index derived from FPG and HbA1c may be able to identify who will have a better response to DPP-4 inhibitors. PMID:28182722

Discovery of Potent and Selective Dipeptidyl Peptidase IV Inhibitors Derived from [beta]-Aminoamides Bearing Subsituted Triazolopiperazines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Dooseop; Kowalchick, Jennifer E.; Brockunier, Linda L.

2008-06-30

A series of {beta}-aminoamides bearing triazolopiperazines have been discovered as potent, selective, and orally active dipeptidyl peptidase IV (DPP-4) inhibitors by extensive structure-activity relationship (SAR) studies around the triazolopiperazine moiety. Among these, compound 34b with excellent in vitro potency (IC{sub 50} = 4.3 nM) against DPP-4, high selectivity over other enzymes, and good pharmacokinetic profiles exhibited pronounced in vivo efficacy in an oral glucose tolerance test (OGTT) in lean mice. On the basis of these properties, compound 34b has been profiled in detail. Further refinement of the triazolopiperazines resulted in the discovery of a series of extremely potent compounds withmore » subnanomolar activity against DPP-4 (42b-49b), that is, 4-fluorobenzyl-substituted compound 46b, which is notable for its superior potency (IC{sub 50} = 0.18 nM). X-ray crystal structure determination of compounds 34b and 46b in complex with DPP-4 enzyme revealed that (R)-stereochemistry at the 8-position of triazolopiperazines is strongly preferred over (S) with respect to DPP-4 inhibition.« less

Incretin Therapy – Present and Future

PubMed Central

Garber, Alan J.

2011-01-01

Although newer treatments for type 2 diabetes (T2D) patients have produced continual improvements in outcome, a large and growing population with prediabetes remains under-treated. In the last few years, incretin-based therapies have become an important treatment option for patients with T2D. There are two classes of incretin agents: the dipeptidyl peptidase-4 (DPP-4) inhibitors and the glucagon like peptide 1 (GLP-1) receptor agonists. The ultimate goal of agents within both of these classes is to increase GLP-1 signaling, which results in augmented glucose-induced insulin secretion, inhibition of glucagon secretion, and decreased appetite. This should result in improved regulation of glucose homeostasis. GLP-1 receptor agonists enable patients to achieve significant weight loss. In contrast, DPP-4 inhibitors result in a less dramatic increase in GLP-1 levels; therefore, they are weight neutral. Incretin therapies are currently recommended for use early in the treatment algorithm for T2D patients whose disease is not manageable by diet and exercise alone, but the potential for these agents may be farther reaching. Current studies are evaluating the potential benefits of combining incretin therapies with basal insulin to provide continuous glucose control before and after meals. In addition, these agents may be promising for patients with prediabetes since they effectively reduce glycosylated hemoglobin levels and fasting plasma glucose levels, enable weight control, and have the potential to preserve β-cell function. Clearly, all of these properties are desirable for patients with prediabetes. PMID:22262069

Hepatic Dipeptidyl Peptidase-4 Controls Pharmacokinetics of Vildagliptin In Vivo.

PubMed

Asakura, Mitsutoshi; Fukami, Tatsuki; Nakajima, Miki; Fujii, Hideaki; Atsuda, Koichiro; Itoh, Tomoo; Fujiwara, Ryoichi

2017-02-01

The main route of elimination of vildagliptin, which is an inhibitor of dipeptidyl peptidase-4 (DPP-4), in humans is cyano group hydrolysis to produce a carboxylic acid metabolite M20.7. Our in vitro study previously demonstrated that DPP-4 itself greatly contributed to the hydrolysis of vildagliptin in mouse, rat, and human livers. To investigate whether hepatic DPP-4 contributes to the hydrolysis of vildagliptin in vivo, in the present study, we conducted in vivo pharmacokinetics studies of vildagliptin in mice coadministered with vildagliptin and sitagliptin, which is another DPP-4 inhibitor, and also in streptozotocin (STZ)-induced diabetic mice. The area under the plasma concentration-time curve (AUC) value of M20.7 in mice coadministered with vildagliptin and sitagliptin was significantly lower than that in mice administered vildagliptin alone (P < 0.01). Although plasma DPP-4 expression level was increased 1.9-fold, hepatic DPP-4 activity was decreased in STZ-induced diabetic mice. The AUC values of M20.7 in STZ-induced diabetic mice were lower than those in control mice (P < 0.01). Additionally, the AUC values of M20.7 significantly positively correlated with hepatic DPP-4 activities in the individual mice (Rs = 0.943, P < 0.05). These findings indicated that DPP-4 greatly contributed to the hydrolysis of vildagliptin in vivo and that not plasma, but hepatic DPP-4 controlled pharmacokinetics of vildagliptin. Furthermore, enzyme assays of 23 individual human liver samples showed that there was a 3.6-fold interindividual variability in vildagliptin-hydrolyzing activities. Predetermination of the interindividual variability of hepatic vildagliptin-hydrolyzing activity might be useful for the prediction of blood vildagliptin concentrations in vivo. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

Dipeptidyl peptidase-4: A key player in chronic liver disease

PubMed Central

Itou, Minoru; Kawaguchi, Takumi; Taniguchi, Eitaro; Sata, Michio

2013-01-01

Dipeptidyl peptidase-4 (DPP-4) is a membrane-associated peptidase, also known as CD26. DPP-4 has widespread organ distribution throughout the body and exerts pleiotropic effects via its peptidase activity. A representative target peptide is glucagon-like peptide-1, and inactivation of glucagon-like peptide-1 results in the development of glucose intolerance/diabetes mellitus and hepatic steatosis. In addition to its peptidase activity, DPP-4 is known to be associated with immune stimulation, binding to and degradation of extracellular matrix, resistance to anti-cancer agents, and lipid accumulation. The liver expresses DPP-4 to a high degree, and recent accumulating data suggest that DPP-4 is involved in the development of various chronic liver diseases such as hepatitis C virus infection, non-alcoholic fatty liver disease, and hepatocellular carcinoma. Furthermore, DPP-4 occurs in hepatic stem cells and plays a crucial role in hepatic regeneration. In this review, we described the tissue distribution and various biological effects of DPP-4. Then, we discussed the impact of DPP-4 in chronic liver disease and the possible therapeutic effects of a DPP-4 inhibitor. PMID:23613622

Cathepsin D plays a role in endothelial-pericyte interactions during alteration of the blood-retinal barrier in diabetic retinopathy.

PubMed

Monickaraj, Finny; McGuire, Paul; Das, Arup

2018-05-01

Inflammation plays an important role in the pathogenesis of diabetic retinopathy. We have previously demonstrated the effect of cathepsin D (CD) on the mechanical disruption of retinal endothelial cell junctions and increased vasopermeability, as well as increased levels of CD in retinas of diabetic mice. Here, we have also examined the effect of CD on endothelial-pericyte interactions, as well as the effect of dipeptidyl peptidase-4 (DPP4) inhibitor on CD in endothelial-pericyte interactions in vitro and in vivo. Cocultured cells that were treated with pro-CD demonstrated a significant decrease in the expression of platelet-derived growth factor receptor-β, a tyrosine kinase receptor that is required for pericyte cell survival; N-cadherin, the key adherens junction protein between endothelium and pericytes; and increases in the vessel destabilizing agent, angiopoietin-2. The effect was reversed in cells that were treated with DPP4 inhibitor along with pro-CD. With pro-CD treatment, there was a significant increase in the phosphorylation of the downstream signaling protein, PKC-α, and Ca 2+ /calmodulin-dependent protein kinase II in endothelial cells and pericytes, which disrupts adherens junction structure and function, and this was significantly reduced with DPP4 inhibitor treatment. Increased CD levels, vasopermeability, and alteration in junctional-related proteins were observed in the retinas of diabetic rats, which were significantly changed with DPP4 inhibitor treatment. Thus, DPP4 inhibitors may be used as potential adjuvant therapeutic agents to treat increased vascular leakage observed in patients with diabetic macular edema.-Monickaraj, F., McGuire, P., Das, A. Cathepsin D plays a role in endothelial-pericyte interactions during alteration of the blood-retinal barrier in diabetic retinopathy.

Saxagliptin reduces renal tubulointerstitial inflammation, hypertrophy and fibrosis in diabetes.

PubMed

Gangadharan Komala, Muralikrishna; Gross, Simon; Zaky, Amgad; Pollock, Carol; Panchapakesan, Usha

2016-05-01

In addition to lowering blood glucose in patients with type 2 diabetes mellitus, dipeptidyl peptidase 4 (DPP4) inhibitors have been shown to be antifibrotic and anti-inflammatory. We have previously shown that DPP4 inhibition in human kidney proximal tubular cells exposed to high glucose reduced fibrotic and inflammatory markers. Hence, we wanted to demonstrate renoprotection in an in vivo model. We used a type 1 diabetic animal model to explore the renoprotective potential of saxagliptin independent of glucose lowering. We induced diabetes in enos -/- mice using streptozotocin and matched glucose levels using insulin. Diabetic mice were treated with saxagliptin and outcomes compared with untreated diabetic mice. We provide novel data that saxagliptin limits renal hypertrophy, transforming growth factor beta-related fibrosis and NF-κBp65-mediated macrophage infiltration. Overall, there was a reduction in histological markers of tubulointerstitial fibrosis. There was no reduction in albuminuria or glomerulosclerosis. Our findings highlight the potential of DPP4 inhibition as additional therapy in addressing the multiple pathways to achieve renoprotection in diabetic nephropathy. © 2015 Asian Pacific Society of Nephrology.

[Cardiovascular Effects of Antidiabetic Therapies].

PubMed

Laubner, Katharina; Seufert, Jochen

2017-05-01

Type 2- diabetes mellitus (T2DM) represents a major risk factor for cardiovascular complications and mortality. Strict glucose control in the early course of the disease prevents cardiovascular complications only in the long run. Non-medical therapies (diet, exercise, body weight reduction) bear little evidence for positive cardiovascular effects.Bariatric surgery is not number one choice in therapy of T2DM. Metformin seems to provide positive cardiovascular effects. Insulin seems to be cardiovascular neutral, as well as the DPP4-inhibitors Saxagliptin, Sitagliptin and Alogliptin. Concerning GLP-1-RAs, Lixisenatide has a neutral cardiovascular effect, whereas Liraglutide and Semaglutide reduce cardiovascular outcomes. The SGLT2-inhibitor Empagliflozin reduces cardiovascular mortality, total mortality and hospitalization by heart failure. © Georg Thieme Verlag KG Stuttgart · New York.

Incretin therapies: highlighting common features and differences in the modes of action of glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors.

PubMed

Nauck, M

2016-03-01

Over the last few years, incretin-based therapies have emerged as important agents in the treatment of type 2 diabetes (T2D). These agents exert their effect via the incretin system, specifically targeting the receptor for the incretin hormone glucagon-like peptide 1 (GLP-1), which is partly responsible for augmenting glucose-dependent insulin secretion in response to nutrient intake (the 'incretin effect'). In patients with T2D, pharmacological doses/concentrations of GLP-1 can compensate for the inability of diabetic β cells to respond to the main incretin hormone glucose-dependent insulinotropic polypeptide, and this is therefore a suitable parent compound for incretin-based glucose-lowering medications. Two classes of incretin-based therapies are available: GLP-1 receptor agonists (GLP-1RAs) and dipeptidyl peptidase-4 (DPP-4) inhibitors. GLP-1RAs promote GLP-1 receptor (GLP-1R) signalling by providing GLP-1R stimulation through 'incretin mimetics' circulating at pharmacological concentrations, whereas DPP-4 inhibitors prevent the degradation of endogenously released GLP-1. Both agents produce reductions in plasma glucose and, as a result of their glucose-dependent mode of action, this is associated with low rates of hypoglycaemia; however, there are distinct modes of action resulting in differing efficacy and tolerability profiles. Furthermore, as their actions are not restricted to stimulating insulin secretion, these agents have also been associated with additional non-glycaemic benefits such as weight loss, improvements in β-cell function and cardiovascular risk markers. These attributes have made incretin therapies attractive treatments for the management of T2D and have presented physicians with an opportunity to tailor treatment plans. This review endeavours to outline the commonalities and differences among incretin-based therapies and to provide guidance regarding agents most suitable for treating T2D in individual patients. © 2015 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.

Dipeptidyl Peptidase-4 Inhibitor Anagliptin Prevents Intracranial Aneurysm Growth by Suppressing Macrophage Infiltration and Activation.

PubMed

Ikedo, Taichi; Minami, Manabu; Kataoka, Hiroharu; Hayashi, Kosuke; Nagata, Manabu; Fujikawa, Risako; Higuchi, Sei; Yasui, Mika; Aoki, Tomohiro; Fukuda, Miyuki; Yokode, Masayuki; Miyamoto, Susumu

2017-06-19

Chronic inflammation plays a key role in the pathogenesis of intracranial aneurysms (IAs). DPP-4 (dipeptidyl peptidase-4) inhibitors have anti-inflammatory effects, including suppressing macrophage infiltration, in various inflammatory models. We examined whether a DPP-4 inhibitor, anagliptin, could suppress the growth of IAs in a rodent aneurysm model. IAs were surgically induced in 7-week-old male Sprague Dawley rats, followed by oral administration of 300 mg/kg anagliptin. We measured the morphologic parameters of aneurysms over time and their local inflammatory responses. To investigate the molecular mechanisms, we used lipopolysaccharide-treated RAW264.7 macrophages. In the anagliptin-treated group, aneurysms were significantly smaller 2 to 4 weeks after IA induction. Anagliptin inhibited the accumulation of macrophages in IAs, reduced the expression of MCP-1 (monocyte chemotactic protein 1), and suppressed the phosphorylation of p65. In lipopolysaccharide-stimulated RAW264.7 cells, anagliptin treatment significantly reduced the production of tumor necrosis factor α, MCP-1, and IL-6 (interleukin 6) independent of GLP-1 (glucagon-like peptide 1), the key mediator in the antidiabetic effects of DPP-4 inhibitors. Notably, anagliptin activated ERK5 (extracellular signal-regulated kinase 5), which mediates the anti-inflammatory effects of statins, in RAW264.7 macrophages. Preadministration with an ERK5 inhibitor blocked the inhibitory effect of anagliptin on MCP-1 and IL-6 expression. Accordingly, the ERK5 inhibitor also counteracted the suppression of p65 phosphorylation in vitro. A DPP-4 inhibitor, anagliptin, prevents the growth of IAs via its anti-inflammatory effects on macrophages. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Early and late effects of the DPP-4 inhibitor vildagliptin in a rat model of post-myocardial infarction heart failure

PubMed Central

2011-01-01

Background Progressive remodeling after myocardial infarction (MI) is a leading cause of morbidity and mortality. Recently, glucagon-like peptide (GLP)-1 was shown to have cardioprotective effects, but treatment with GLP-1 is limited by its short half-life. It is rapidly degraded by the enzyme dipeptidyl peptidase-4 (DPP-4), an enzyme which inhibits GLP-1 activity. We hypothesized that the DPP-4 inhibitor vildagliptin will increase levels of GLP-1 and may exert protective effects on cardiac function after MI. Methods Sprague-Dawley rats were either subjected to coronary ligation to induce MI and left ventricular (LV) remodeling, or sham operation. Parts of the rats with an MI were pre-treated for 2 days with the DPP-4 inhibitor vildagliptin (MI-Vildagliptin immediate, MI-VI, 15 mg/kg/day). The remainder of the rats was, three weeks after coronary artery ligation, subjected to treatment with DPP-4 inhibitor vildagliptin (MI-Vildagliptin Late, MI-VL) or control (MI). At 12 weeks, echocardiography and invasive hemodynamics were measured and molecular analysis and immunohistochemistry were performed. Results Vildagliptin inhibited the DPP-4 enzymatic activity by almost 70% and increased active GLP-1 levels by about 3-fold in plasma in both treated groups (p < 0.05 vs. non-treated groups). Cardiac function (ejection fraction) was decreased in all 3 MI groups compared with Sham group (p < 0.05); treatment with vildagliptin, either early or late, did not reverse cardiac remodeling. ANP (atrial natriuretic peptide) and BNP (brain natriuretic peptide) mRNA levels were significantly increased in all 3 MI groups, but no significant reductions were observed in both vildagliptin groups. Vildagliptin also did not change cardiomyocyte size or capillary density after MI. No effects were detected on glucose level and body weight in the post-MI remodeling model. Conclusion Vildagliptin increases the active GLP-1 level via inhibition of DPP-4, but it has no substantial protective effects on cardiac function in this well established long-term post-MI cardiac remodeling model. PMID:21955567

The persistent inhibitory properties of saxagliptin on renal dipeptidyl peptidase-4: Studies with HK-2 cells in vitro and normal rats in vivo.

PubMed

Uchii, Masako; Sakai, Mariko; Hotta, Yuhei; Saeki, Satoshi; Kimoto, Naoya; Hamaguchi, Akinori; Kitayama, Tetsuya; Kunori, Shunji

2017-11-01

Saxagliptin, a potent and selective DPP-4 inhibitor, exhibits a slow dissociation from DPP-4. We investigated the sustained effects of saxagliptin on renal DPP-4 activity in a washout study using renal tubular (HK-2) cells, and in a pharmacodynamic study using normal rats. In HK-2 cells, the inhibitory potency of saxagliptin on DPP-4 activity persisted after washout, while that of sitagliptin was clearly reduced. In normal rats, a single treatment of saxagliptin or sitagliptin inhibited the plasma DPP-4 activity to similar levels. The inhibitory action of saxagliptin on the renal DPP-4 activity was retained, even when its inhibitory effect on the plasma DPP-4 activity disappeared. However, the inhibitory action of sitagliptin on the renal DPP-4 activity was abolished in correlation with the inhibition of the plasma DPP-4 activity. In situ staining showed that saxagliptin suppressed the DPP-4 activity in both glomerular and tubular cells and its inhibitory effects were significantly higher than those of sitagliptin. Saxagliptin exerted a sustained inhibitory effect on the renal DPP-4 activity in vitro and in vivo. The long binding action of saxagliptin in renal tubular cells might involve the sustained inhibition of renal DPP-4. Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

(2S,4S)-4-Fluoro-1-{[(2-hydroxy-1,1-dimethylethyl)amino]acetyl}-pyrrolidine-2-carbonitrile monobenzenesulfonate (TS-021) is a selective and reversible dipeptidyl peptidase IV inhibitor.

PubMed

Tajima, Atsushi; Yamamoto, Koji; Kozakai, Akinori; Okumura-Kitajima, Lisa; Mita, Yasuo; Kitano, Kiyokazu; Jingu, Shigeji; Nakaike, Shiro

2011-03-25

The incretin hormone glucagon-like peptide-1 (GLP-1) has significant roles in the regulation of postprandial glucose metabolism, and the active form of GLP-1 is rapidly degraded by dipeptidyl peptidase (DPP)-IV. Therefore, DPP-IV inhibition is a promising approach for the treatment of type 2 diabetes. In the present study, we investigated the character of a DPP-IV inhibitor, TS-021, (2S, 4S)-4-fluoro-1-{[(2-hydroxy-1,1-dimethylethyl)amino]acetyl}-pyrrolidine-2-carbonitrile monobenzenesulfonate both in vitro and in vivo. TS-021 inhibits DPP-IV activity in human plasma with an IC(50) value of 5.34nM. In kinetics experiments, TS-021 had a relatively higher dissociation rate constant, with a k(off) value of 1.09×10(-3)s, despite exhibiting a potent human plasma DPP-IV inhibition activity with a K(i) value of 4.96nM. TS-021 exhibited significant inhibition selectivity against DPP-8 (>600 fold), DPP-9 (>1200 fold) and other peptidases examined (>15,000 fold). In normal rats, dogs and monkeys, a single oral dose of TS-021 exhibited favorable pharmacokinetic profiles. In Zucker fatty (fa/fa) rats, a rat model of obesity and impaired glucose tolerance, the oral administration of TS-021 resulted in the suppression of plasma DPP-IV activity and an increase in the active form of GLP-1. Furthermore, TS-021 exhibited a significant improvement in glucose tolerance by increasing the plasma insulin level during oral glucose tolerance tests at doses of 0.02-0.5mg/kg. These results suggest that TS-021 is a selective and reversible dipeptidyl peptidase IV inhibitor and has excellent characteristics as an oral anti-diabetic agent for postprandial hyperglycemia in patients with impaired glucose tolerance or type 2 diabetes. Copyright © 2011 Elsevier B.V. All rights reserved.

Dipeptidyl peptidase-4 inhibitors-associated bullous pemphigoid: a retrospective study of 168 pemphigoid and 9,304 diabetes mellitus cases.

PubMed

Kawaguchi, Yohei; Shimauchi, Risa; Nishibori, Nobuhiro; Kawashima, Kiyohito; Oshitani, So; Fujiya, Atsushi; Shibata, Taiga; Ohashi, Norimi; Izumi, Kentaro; Nishie, Wataru; Shimizu, Hiroshi; Arima, Hiroshi; Sobajima, Hiroshi

2018-06-19

Bullous pemphigoid (BP) may be drug-induced. This study evaluated the relation between BP and dipeptidyl peptidase-4 inhibitors (DPP4Is). We recruited patients diagnosed with BP at Ogaki Municipal Hospital from December 1, 2009 through December 31, 2017. We retrospectively collected data from medical records and divided patients into two groups based on whether they received DPP4Is. Additionally, we determined the incidence of BP in patients who were first prescribed DPP4Is at our hospital during the study period. Of 168 patients diagnosed with BP, 133 (79.1%) were positive for anti-BP180NC16a antibody. Thirty-two (19.0%) patients had been prescribed a DPP4I, 21 of whom (65.6%) were positive for anti-BP180NC16a antibody; this rate was lower than that in patients not receiving a DPP4I (82.3%) (p = 0.0360). Sixteen patients with type 2 diabetes mellitus (T2DM) had not been prescribed a DPP4I; only one (6.3%) was positive for anti-BP180NC16a antibody (p = 0.0339). During the study period, 9304 patients were prescribed DPP4Is, eight of whom developed BP; six (75.0%) had non-inflammatory BP, and five of the six (83.3%) were negative for anti-BP180NC16a antibody. The positive rate of anti-BP180NC16a antibody was lower in BP patients with DPP4I than without DPP4I, regardless of T2DM. The antibody titer was low in both the overall and T2DM populations. The prevalence of BP in 9304 patients receiving DPP4Is was 0.0859%, which is higher than that in the general population. Since DPP4Is are common diabetes treatments, we must be aware of the risk of BP. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Inhibitory effect of collagen-derived tripeptides on dipeptidylpeptidase-IV activity.

PubMed

Hatanaka, Tadashi; Kawakami, Kayoko; Uraji, Misugi

2014-12-01

The collagen tripeptide fragments Gly-Ala-Hyp, Gly-Pro-Ala and Gly-Pro-Hyp were generated by hydrolyzing collagen from pig-skin, cattle-skin, fish-scales and chicken-feet, respectively, with Streptomyces collagenase. Collagenase treatment increased the concentration of tripeptides in the hydrolysates by 13-15% (w/w). Of the three peptides, Gly-Pro-Hyp was a true peptidic inhibitor of dipeptidylpeptidase-IV (DPP-IV), because DPP-IV could not hydrolyze the bond between Pro-Hyp. This tripeptide was a moderately competitive inhibitor (Ki=4.5 mM) of DPP-IV, and its level in the collagen hydrolysates could be greatly increased (4-9% [w/w]) using Streptomyces collagenase.

[Prandial glucose regulator and insulin secretagogue; glinide and its combination therapy].

PubMed

Nakashima, Eitaro

2015-03-01

The glinides are the therapeutic agents for indications for type 2 diabetic patients with postprandial hyperglycemia. These are a class of drug which have a similar response as sulfonylureas but act for a shorter time and are prescribed to be taken by patients with type 2 diabetes within 5-10 min before eating. As the drugs act for a shorter period than sulfonylureas, the side effects of hypoglycemia and weight gain have a smaller likelihood. Combination with glinides and DPP4 inhibitors is a good choice for type 2 diabetic patients in early stage. Also combination therapy with glinides and alpha-glucosidase inhibitors shows a good profile of daily blood glucose level in these patients.

The DPP-4 inhibitor vildagliptin impacts the gut microbiota and prevents disruption of intestinal homeostasis induced by a Western diet in mice.

PubMed

Olivares, Marta; Neyrinck, Audrey M; Pötgens, Sarah A; Beaumont, Martin; Salazar, Nuria; Cani, Patrice D; Bindels, Laure B; Delzenne, Nathalie M

2018-05-25

Dipeptidyl peptidase 4 (DPP-4) inhibitors are agents designed to increase the half-life of incretins. Although they are administered orally, little is known about their effects on the gut microbiota and functions, despite the fact that some bacteria present in the gut microbiota exhibit DPP-4-like activity. Our objective was to study the impact of the DPP-4 inhibitor vildagliptin on gut functions and the intestinal ecosystem in a murine model of obesity induced by a Western diet (WD). Twenty seven male C57BL/6J mice were randomised to receive a control diet, a WD (45% kJ from fat and 17% kJ from sucrose) or a WD + vildagliptin (0.6 mg/ml in drinking water) for 8 weeks. Vildagliptin significantly reduced DPP-4 activity in the caecal content and faeces. Vildagliptin impacted on the composition of the gut microbiota and its metabolic activity. It mainly decreased Oscillibacter spp. (a direct effect independent of DPP-4 activity was shown on cultured O. valericigenes), increased Lactobacillus spp. and propionate, and reduced the ligands of Toll-like receptors 2 and 4. Vildagliptin protected against the reductions in crypt depth and ileal expression of antimicrobial peptides induced by the WD. In the liver, the expression of immune cell populations (Cd3g and Cd11c [also known as Itgax]) and cytokines was decreased in the WD + vildagliptin-fed mice compared with the WD-fed group. Ex vivo exposure of precision-cut liver slices to vildagliptin showed that this response was not related to a direct effect of the drug on the liver tissue. Our study is the first to consider the DPP-4-like activity of the gut microbiota as a target of DPP-4 inhibition. We propose that vildagliptin exerts beneficial effects at the intestinal level in association with modulation of gut microbiota, with consequences for hepatic immunity. If relevant in humans, this could open new therapeutic uses of DPP-4 inhibition to tackle gut dysfunctions in different pathophysiological contexts. The sequences used for analysis can be found in the MG-RAST database under the project name MYNEWGUT3.

Anti-inflammatory effects on ischemia/reperfusion-injured lung transplants by the cluster of differentiation 26/dipeptidylpeptidase 4 (CD26/DPP4) inhibitor vildagliptin.

PubMed

Jang, Jae-Hwi; Yamada, Yoshito; Janker, Florian; De Meester, Ingrid; Baerts, Lesley; Vliegen, Gwendolyn; Inci, Ilhan; Chatterjee, Shampa; Weder, Walter; Jungraithmayr, Wolfgang

2017-03-01

We showed previously that stromal cell-derived factor 1 (SDF-1) is a substrate of cluster of differentiation 26/dipeptidylpeptidase 4 (CD26/DPP4) and exerts regenerative properties on acute lung ischemia-reperfusion injury on CD26/DPP4 inhibition. Here, we extend our studies to test whether an intermediate recovery of lung transplants from ischemia/reperfusion injury by CD26/DPP4 inhibition can be achieved for up to 14 days. Syngeneic mouse lung transplantation (Tx) was performed in C57BL/6 and in CD26-/- mice by applying 18 hours of cold ischemia. Donor lungs were preconditioned with saline or the CD26/DPP4 inhibitor vildagliptin (1 μg/mL [3 μM]). In vitro, the influence of vildagliptin and SDF-1 on the macrophage cell line RAW 264.7 was tested. Transplants were analyzed up to 14 days after Tx for the expression of SDF-1, tumor necrosis factor-α (TNF-α), interleukin-10, intercellular adhesion molecule-1 (ICAM-1), immune cell infiltration, and oxygenation. Cold ischemic time of 18 hours with vildagliptin preconditioning elevated lung SDF-1 levels (P = .0011) and increased interleukin-10-producing macrophages (P = .0165) compared with the control. SDF-1 reduced macrophage-derived TNF-α (P = .0248) in vitro. Five hours after Tx, vildagliptin significantly reduced macrophages and neutrophils (P = .0306), decreased ICAM-1 expression (P = .002), and improved transplant oxygenation (P = .0181). Seven days after Tx, grafts were preserved on CD26/DPP4-inhibition: perivascular macrophages (P = .0046) and TNF-α (P = .0013) were reduced as well as T and B cells. ICAM-1 was absent in CD26/DPP4-inhibited grafts at all time points. This study proves an intermediate improvement of ischemia/reperfusion-injured lung transplants by the CD26/DPP4-inhibitor vildagliptin up to 14 days. Enhanced levels of SDF-1 induced an anti-inflammatory effect on a cellular and protein level, and render CD26/DPP4 inhibition preconditioning effective for the protection from lung ischemia/reperfusion injury. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Genetic ablation or pharmacological blockade of dipeptidyl peptidase IV does not impact T cell-dependent immune responses

PubMed Central

Vora, Kalpit A; Porter, Gene; Peng, Roche; Cui, Yan; Pryor, Kellyann; Eiermann, George; Zaller, Dennis M

2009-01-01

Background Current literature suggests that dipeptidyl peptidase IV (DPP-IV; CD26) plays an essential role in T-dependent immune responses, a role that could have important clinical consequences. To rigorously define the role of DPP-IV in the immune system, we evaluated genetic and pharmacological inhibition of the enzyme on T-dependent immune responses in vivo. Results The DPP-IV null animals mounted robust primary and secondary antibody responses to the T dependent antigens, 4-hydroxy-3-nitrophenylacetyl-ovalbumin (NP-Ova) and 4-hydroxy-3-nitrophenylacetyl-chicken gamma globulin (NP-CGG), which were comparable to wild type mice. Serum levels of antigen specific IgM, IgG1, IgG2a, IgG2b and IgG3 were similar between the two groups of animals. DPP-IV null animals mounted an efficient germinal center reaction by day 10 after antigen stimulation that was comparable to wild type mice. Moreover, the antibodies produced by DPP-IV null animals after repeated antigenic challenge were affinity matured. Similar observations were made using wild type animals treated with a highly selective DPP-IV inhibitor during the entire course of the experiments. T cell recall responses to ovalbumin and MOG peptide, evaluated by measuring proliferation and IL-2 release from cells isolated from draining lymph nodes, were equivalent in DPP-IV null and wild type animals. Furthermore, mice treated with DPP-IV inhibitor had intact T-cell recall responses to MOG peptide. In addition, female DPP-IV null and wild type mice treated with DPP-IV inhibitor exhibited normal and robust in vivo cytotoxic T cell responses after challenge with cells expressing the male H-Y minor histocompatibility antigen. Conclusion These data indicate Selective inhibition of DPP-IV does not impair T dependent immune responses to antigenic challenge. PMID:19358731

Effects of sitagliptin on coronary atherosclerosis evaluated using integrated backscatter intravascular ultrasound in patients with type 2 diabetes: rationale and design of the TRUST study.

PubMed

Nozue, Tsuyoshi; Fukui, Kazuki; Koyama, Yutaka; Fujii, Hiroyuki; Kunishima, Tomoyuki; Hikita, Hiroyuki; Hibi, Kiyoshi; Miyazawa, Akiyoshi; Michishita, Ichiro

2016-05-01

Patients with diabetes mellitus are at high risk for developing coronary artery disease (CAD), even if they are treated with statins. Several studies have shown the beneficial effects of dipeptidyl peptidase-4 (DPP-4) inhibitors on the cardiovascular system in an animal model. However, recent clinical trials using DPP-4 inhibitors have shown that these inhibitors fail to reduce the occurrence of cardiovascular events. Therefore, this study will be performed to evaluate the effects of sitagliptin, a DPP-4 inhibitor, on coronary atherosclerosis in patients with type 2 diabetes. This study will be a prospective, open-label, randomized multicenter trial performed in 6 centers in Japan. Stable CAD patients with type 2 diabetes who have undergone successful percutaneous coronary intervention under integrated backscatter (IB)-intravascular ultrasound (IVUS) guidance will be studied. They will be randomly assigned to either the sitagliptin group or a control group. After 48 weeks' treatment, the IVUS examination will be repeated in the same coronary artery as at baseline. The primary end point will be the percentage change in plaque volume measured using grayscale IVUS from baseline to the 48-week follow-up. This study will be the first multicenter trial to evaluate the effects of a DPP-4 inhibitor on coronary atherosclerosis evaluated using IB-IVUS, and the findings will clarify the anti-atherogenic effects of sitagliptin.

Clinical Pharmacokinetics and Pharmacodynamics of Saxagliptin, a Dipeptidyl Peptidase-4 Inhibitor.

PubMed

Boulton, David W

2017-01-01

Saxagliptin is an orally active, highly potent, selective and competitive dipeptidyl peptidase (DPP)-4 inhibitor used in the treatment of type 2 diabetes mellitus at doses of 2.5 or 5 mg once daily. DPP-4 is responsible for degrading the intestinally derived hormones glucagon-like peptide (GLP)-1 and glucose-dependent insulinotropic polypeptide (GIP). Inhibition of DPP-4 increases intact plasma GLP-1 and GIP concentrations, augmenting glucose-dependent insulin secretion. Both saxagliptin and its major active metabolite, 5-hydroxy saxagliptin, demonstrate high degrees of selectivity for DPP-4 compared with other DPP enzymes. Saxagliptin is orally absorbed and can be administered with or without food. The half-life of plasma DPP-4 inhibition with saxagliptin 5 mg is ~27 h, which supports a once-daily dosing regimen. Saxagliptin is metabolized by cytochrome P450 (CYP) 3A4/5 and is eliminated by a combination of renal and hepatic clearance. No clinically meaningful differences in saxagliptin or 5-hydroxy saxagliptin pharmacokinetics have been detected in patients with hepatic impairment. No clinically meaningful differences in saxagliptin or 5-hydroxy saxagliptin pharmacokinetics have been detected in patients with mild renal impairment, whereas dose reduction is recommended in patients with moderate or severe renal impairment because of greater systemic exposure [the area under the plasma concentration-time curve (AUC)] to saxagliptin total active moieties. Clinically relevant drug-drug interactions have not been detected; however, limiting the dose to 2.5 mg once daily is recommended in the USA when saxagliptin is coadministered with strong CYP inhibitors, because of increased saxagliptin exposure. In summary, saxagliptin has a predictable pharmacokinetic and pharmacodynamic profile.

Renal and cardiac effects of DPP4 inhibitors--from preclinical development to clinical research.

PubMed

Hocher, Berthold; Reichetzeder, Christoph; Alter, Markus L

2012-01-01

Inhibitors of type 4 dipeptidyl peptidase (DDP-4) were developed and approved for the oral treatment of type 2 diabetes. Its mode of action is to inhibit the degradation of incretins, such as type 1 glucagon like peptide (GLP-1), and GIP. GLP-1 stimulates glucose-dependent insulin secretion from pancreatic beta-cells and suppresses glucagon release from alpha-cells, thereby improving glucose control. Besides its action on the pancreas type 1 glucagon like peptide has direct effects on the heart, vessels and kidney mainly via the type 1 glucagon like peptide receptor (GLP-1R). Moreover, there are substrates of DPP-4 beyond incretins that have proven renal and cardiovascular effects such as BNP/ANP, NPY, PYY or SDF-1 alpha. Preclinical evidence suggests that DPP-4 inhibitors may be effective in acute and chronic renal failure as well as in cardiac diseases like myocardial infarction and heart failure. Interestingly, large cardiovascular meta-analyses of combined phase II/III clinical trials with DPP-4 inhibitors point all in the same direction: a potential reduction of cardiovascular events in patients treated with these agents. A pooled analysis of pivotal phase III, placebo-controlled, registration studies of linagliptin further showed a significant reduction of urinary albumin excretion after 24 weeks of treatment. The observation suggests direct renoprotective effects of DPP-4 inhibition that may go beyond its glucose-lowering potential. Type 4 dipeptidyl peptidase inhibitors have been shown to be very well tolerated in general, but for those excreted via the kidney dose adjustments according to renal function are needed to avoid side effects. In conclusion, the direct cardiac and renal effects seen in preclinical studies as well as meta-analysis of clinical trials may offer additional potentials - beyond improvement of glycemic control - for this newer class of drugs, such as acute kidney failure, chronic kidney failure as well as acute myocardial infarction and heart failure. Copyright © 2012 S. Karger AG, Basel.

Effect of dipeptidyl peptidase-4 inhibitors on circulating tumor necrosis factor-α concentrations: A systematic review and meta-analysis of controlled trials.

PubMed

Atkin, Stephen L; Katsiki, Niki; Banach, Maciej; Mikhailidis, Dimitri P; Pirro, Matteo; Sahebkar, Amirhossein

2017-09-01

Dipeptidyl peptidase-4 (DPP-4) inhibitors improve glycemic control in patients with type 2 diabetes mellitus. There are also reports of an effect of these drugs in reducing inflammation through inhibition of tumor necrosis factor-α (TNF-α) that is an important mediator for several inflammatory processes. The present systematic review and meta-analysis were performed to evaluate the effect of DPP-4 inhibitors on circulating TNF-α levels in T2DM patients. A systematic review and a meta-analysis were undertaken on all controlled trials of DPP-4 inhibitors that included measurement of TNF-α. The search included PubMed-Medline, Scopus, ISI Web of Knowledge and Google Scholar databases. Quantitative data synthesis was performed using a random-effects model, with standardized mean difference (SMD) and 95% confidence interval (CI) as summary statistics. Meta-regression and leave-one-out sensitivity analysis were performed to assess the modifiers of treatment response. Eight eligible articles (6 with sitagliptin and 2 with vildagliptin) comprising 9 treatment arms were selected for this meta-analysis. Meta-analysis suggested a significant reduction of circulating TNF-α concentrations following treatment with DPP-4 inhibitors (SMD: -1.84, 95% CI: -2.88, -0.80, p=0.001). The effect size was robust in the sensitivity analysis and not mainly driven by a single study. A subgroup analysis did not suggest any significant difference between the TNF-α-lowering activity of sitagliptin (SMD: -1.49, 95% CI: -2.89, -0.10) and vildagliptin (SMD: -2.80, 95% CI: -4.98, -0.61) (p=0.326). This meta-analysis of the 8 available controlled trials showed that DPP-4 inhibition in patients with type 2 diabetes mellitus was associated with significant reductions in plasma TNF-α levels with no apparent difference between sitagliptin and vildagliptin. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of miglitol, vildagliptin, or their combination on serum insulin and peptide YY levels and plasma glucose, cholecystokinin, ghrelin, and obestatin levels.

PubMed

Aoki, Kazutaka; Kamiyama, Hiroshi; Masuda, Kiyomi; Kamiko, Kazunari; Noguchi, Yoshihiko; Tajima, Kazuki; Terauchi, Yasuo

2014-01-01

We previously reported that combination therapy with an α-glucosidase inhibitor (αGI) and a dipeptidyl peptidase-4 (DPP-4) inhibitor increased active glucagon-like peptide-1 (GLP-1) levels and decreased total glucose-dependent insulinotropic polypeptide (GIP) levels, compared with monotherapy, in non-diabetic men. However, the peptide YY (PYY), cholecystokinin (CCK), ghrelin, and obestatin levels in patients receiving a combination of αGIs and DPP-4 inhibitors have not been previously reported. We evaluated the effect of miglitol, vildagliptin, or their combination on these parameters. Miglitol and/or vildagliptin were administered according to four different intake schedules in eleven non-diabetic men (C: no drug, M: miglitol; V: vildagliptin, M+V: miglitol+vildagliptin). Blood samples were collected at 0, 30, 60, and 120 min after the start of breakfast. The plasma glucose, serum insulin, serum total PYY (PYY1-36 and PYY3-36), plasma CCK, plasma active ghrelin, and plasma obestatin levels were measured. The area under the curve (AUC) of the serum total PYY level in the M group was significantly greater than that in the C group, and the AUC of the serum total PYY level in the M+V group was significantly lower than that in the M group. The combination therapy did not change the AUC of the plasma CCK, plasma active ghrelin, plasma obestatin, and ghrelin/obestatin levels, compared with the control. The results of our study suggested that combination therapy with miglitol and vildagliptin had no effect on appetite regulation hormones, such as total PYY, CCK, active ghrelin, and obestatin, compared with the levels in the control group.

The effects of GLP-1 analogues, DPP-4 inhibitors and SGLT2 inhibitors on the renal system.

PubMed

Schernthaner, Guntram; Mogensen, Carl Erik; Schernthaner, Gerit-Holger

2014-09-01

Diabetic nephropathy (DN) affects an estimated 20%-40% of patients with type 2 diabetes mellitus (T2DM). Key modifiable risk factors for DN are albuminuria, anaemia, dyslipidaemia, hyperglycaemia and hypertension, together with lifestyle factors, such as smoking and obesity. Early detection and treatment of these risk factors can prevent DN or slow its progression, and may even induce remission in some patients. DN is generally preceded by albuminuria, which frequently remains elevated despite treatment in patients with T2DM. Optimal treatment and prevention of DN may require an early, intensive, multifactorial approach, tailored to simultaneously target all modifiable risk factors. Regular monitoring of renal function, including urinary albumin excretion, creatinine clearance and glomerular filtration rate, is critical for following any disease progression and making treatment adjustments. Dipeptidyl peptidase (DPP)-4 inhibitors and sodium-glucose cotransporter 2 (SGLT2) inhibitors lower blood glucose levels without additional risk of hypoglycaemia, and may also reduce albuminuria. Further investigation of the potential renal benefits of DPP-4 and SGLT2 inhibitors is underway. © The Author(s) 2014.

The effects of GLP-1 analogues, DPP-4 inhibitors and SGLT2 inhibitors on the renal system

PubMed Central

Mogensen, Carl Erik; Schernthaner, Gerit-Holger

2014-01-01

Diabetic nephropathy (DN) affects an estimated 20%–40% of patients with type 2 diabetes mellitus (T2DM). Key modifiable risk factors for DN are albuminuria, anaemia, dyslipidaemia, hyperglycaemia and hypertension, together with lifestyle factors, such as smoking and obesity. Early detection and treatment of these risk factors can prevent DN or slow its progression, and may even induce remission in some patients. DN is generally preceded by albuminuria, which frequently remains elevated despite treatment in patients with T2DM. Optimal treatment and prevention of DN may require an early, intensive, multifactorial approach, tailored to simultaneously target all modifiable risk factors. Regular monitoring of renal function, including urinary albumin excretion, creatinine clearance and glomerular filtration rate, is critical for following any disease progression and making treatment adjustments. Dipeptidyl peptidase (DPP)-4 inhibitors and sodium-glucose cotransporter 2 (SGLT2) inhibitors lower blood glucose levels without additional risk of hypoglycaemia, and may also reduce albuminuria. Further investigation of the potential renal benefits of DPP-4 and SGLT2 inhibitors is underway. PMID:25116004

Inhibition of dipeptidyl peptidase IV prevents high fat diet-induced liver cancer angiogenesis by downregulating chemokine ligand 2.

PubMed

Qin, Chen-Jie; Zhao, Ling-Hao; Zhou, Xu; Zhang, Hui-Lu; Wen, Wen; Tang, Liang; Zeng, Min; Wang, Ming-Da; Fu, Gong-Bo; Huang, Shuai; Huang, Wei-Jian; Yang, Yuan; Bao, Zhi-Jun; Zhou, Wei-Ping; Wang, Hong-Yang; Yan, He-Xin

2018-04-28

Obesity is a major risk factor for hepatocellular carcinoma (HCC) and is typically accompanied by higher levels of serum dipeptidyl peptidase 4 (DPP4). However, the role of DPP4 in obesity-promoted HCC is unclear. Here, we found that consumption of a high-fat diet (HFD) promoted HCC cell proliferation and metastasis and led to poor survival in a carcinogen-induced model of HCC in rats. Notably, genetic ablation of DPP4 or treatment with a DPP4 inhibitor (vildagliptin) prevented HFD-induced HCC. Moreover, HFD-induced DPP4 activity facilitated angiogenesis and cancer cell metastasis in vitro and in vivo, and vildagliptin prevented tumor progression by mediating the pro-angiogenic role of chemokine ligand 2 (CCL2). Loss of DPP4 effectively reversed HFD-induced CCL2 production and angiogenesis, indicating that the DPP4/CCL2/angiogenesis cascade had key roles in HFD-associated HCC progression. Furthermore, concomitant changes in serum DPP4 and CCL2 were observed in 210 patients with HCC, and high serum DPP4 activity was associated with poor clinical prognosis. These results revealed a link between obesity-related high serum DPP4 activity and HCC progression. Inhibition of DPP4 may represent a novel therapeutic intervention for patients with HCC. Copyright © 2018 Elsevier B.V. All rights reserved.

Design and Elaboration of a Tractable Tricyclic Scaffold To Synthesize Druglike Inhibitors of Dipeptidyl Peptidase-4 (DPP-4), Antagonists of the C-C Chemokine Receptor Type 5 (CCR5), and Highly Potent and Selective Phosphoinositol-3 Kinase δ (PI3Kδ) Inhibitors.

PubMed

Schwehm, Carolin; Kellam, Barrie; Garces, Aimie E; Hill, Stephen J; Kindon, Nicholas D; Bradshaw, Tracey D; Li, Jin; Macdonald, Simon J F; Rowedder, James E; Stoddart, Leigh A; Stocks, Michael J

2017-02-23

A novel molecular scaffold has been synthesized, and its incorporation into new analogues of biologically active molecules across multiple target classes will be discussed. In these studies, we have shown use of the tricyclic scaffold to synthesize potent inhibitors of the serine peptidase DPP-4, antagonists of the CCR5 receptor, and highly potent and selective PI3K δ isoform inhibitors. We also describe the predicted physicochemical properties of the resulting inhibitors and conclude that the tractable molecular scaffold could have potential application in future drug discovery programs.

Dipeptidyl peptidase-IV inhibitor use associated with increased risk of ACE inhibitor-associated angioedema.

PubMed

Brown, Nancy J; Byiers, Stuart; Carr, David; Maldonado, Mario; Warner, Barbara Ann

2009-09-01

Dipeptidyl peptidase-IV (DPP-IV) inhibitors decrease degradation of the incretins. DPP-IV inhibitors also decrease degradation of peptides, such as substance P, that may be involved in the pathogenesis of angiotensin-converting enzyme (ACE) inhibitor-associated angioedema. This study tested the hypothesis that DPP-IV inhibition affects risk of clinical angioedema, by comparing the incidence of angioedema in patients treated with the DPP-IV inhibitor vildagliptin versus those treated with comparator in Phase III randomized clinical trials. Prospectively defined angioedema-related events were adjudicated in a blinded fashion by an internal medicine adjudication committee and expert reviewer. Concurrent ACE inhibitor or angiotensin receptor blocker exposure was ascertained from case report forms. Study drug exposure was ascertained from unblinded data from phase III studies. Odds ratios and 95% confidence intervals comparing angioedema risk in vildagliptin-treated and comparator-treated patients were calculated for the overall population and for patients taking ACE inhibitors or angiotensin receptor blockers, using both an analysis of pooled data and a meta-analysis (Peto method). Overall, there was no association between vildagliptin use and angioedema. Among individuals taking an ACE inhibitor, however, vildagliptin use was associated with an increased risk of angioedema (14 confirmed cases among 2754 vildagliptin users versus 1 case among 1819 comparator users: odds ratio 4.57 [95% confidence interval 1.57 to 13.28]) in the meta-analysis. Vildagliptin use may be associated with increased risk of angioedema among patients taking ACE inhibitors, although absolute risk is small. Physicians confronted with angioedema in a patient taking an ACE inhibitor and DPP-IV inhibitor should consider this possible drug-drug interaction.

Add-on therapy with anagliptin in Japanese patients with type-2 diabetes mellitus treated with metformin and miglitol can maintain higher concentrations of biologically active GLP-1/total GIP and a lower concentration of leptin.

PubMed

Osonoi, Takeshi; Saito, Miyoko; Hariya, Natsuyo; Goto, Moritaka; Mochizuki, Kazuki

2016-12-01

Metformin, α-glucosidase inhibitors (α-GIs), and dipeptidyl peptidase 4 inhibitors (DPP-4Is) reduce hyperglycemia without excessive insulin secretion, and enhance postprandial plasma concentration of glucagon-like peptide-1 (GLP-1) in type-2 diabetes mellitus (T2DM) patients. We assessed add-on therapeutic effects of DPP-4I anagliptin in Japanese T2DM patients treated with metformin, an α-GI miglitol, or both drugs on postprandial responses of GLP-1 and glucose-dependent insulinotropic polypeptide (GIP), and on plasma concentration of the appetite-suppressing hormone leptin. Forty-two Japanese T2DM patients with inadequately controlled disease (HbA1c: 6.5%-8.0%) treated with metformin (n=14), miglitol (n=14) or a combination of the two drugs (n=14) received additional treatment with anagliptin (100mg, p.o., b.i.d.) for 52 weeks. We assessed glycemic control, postprandial responses of GLP-1 and glucose-dependent insulinotropic polypeptide (GIP), and on plasma concentration of leptin in those patients. Add-on therapy with anagliptin for 52 weeks improved glycemic control and increased the area under the curve of biologically active GLP-1 concentration without altering obesity indicators. Total GIP concentration at 52 weeks was reduced by add-on therapy in groups treated with miglitol compared with those treated with metformin. Add-on therapy reduced leptin concentrations. Add-on therapy with anagliptin in Japanese T2DM patients treated with metformin and miglitol for 52 weeks improved glycemic control and enhanced postprandial concentrations of active GLP-1/total GIP, and reduce the leptin concentration. Copyright © 2016 Elsevier Inc. All rights reserved.

Oral Pharmacologic Treatment of Type 2 Diabetes Mellitus: A Clinical Practice Guideline Update From the American College of Physicians.

PubMed

Qaseem, Amir; Barry, Michael J; Humphrey, Linda L; Forciea, Mary Ann

2017-02-21

The American College of Physicians (ACP) developed this guideline to present the evidence and provide clinical recommendations on oral pharmacologic treatment of type 2 diabetes in adults. This guideline serves as an update to the 2012 ACP guideline on the same topic. This guideline is endorsed by the American Academy of Family Physicians. This guideline is based on a systematic review of randomized, controlled trials and observational studies published through December 2015 on the comparative effectiveness of oral medications for type 2 diabetes. Evaluated interventions included metformin, thiazolidinediones, sulfonylureas, dipeptidyl peptidase-4 (DPP-4) inhibitors, and sodium-glucose cotransporter-2 (SGLT-2) inhibitors. Study quality was assessed, data were extracted, and results were summarized qualitatively on the basis of the totality of evidence identified by using several databases. Evaluated outcomes included intermediate outcomes of hemoglobin A1c, weight, systolic blood pressure, and heart rate; all-cause mortality; cardiovascular and cerebrovascular morbidity and mortality; retinopathy, nephropathy, and neuropathy; and harms. This guideline grades the recommendations by using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. The target audience for this guideline includes all clinicians, and the target patient population includes adults with type 2 diabetes. ACP recommends that clinicians prescribe metformin to patients with type 2 diabetes when pharmacologic therapy is needed to improve glycemic control. (Grade: strong recommendation; moderate-quality evidence). ACP recommends that clinicians consider adding either a sulfonylurea, a thiazolidinedione, an SGLT-2 inhibitor, or a DPP-4 inhibitor to metformin to improve glycemic control when a second oral therapy is considered. (Grade: weak recommendation; moderate-quality evidence.) ACP recommends that clinicians and patients select among medications after discussing benefits, adverse effects, and costs.

Glucagon-Like Peptide 1 Analogs and their Effects on Pancreatic Islets.

PubMed

Tudurí, Eva; López, Miguel; Diéguez, Carlos; Nadal, Angel; Nogueiras, Rubén

2016-05-01

Glucagon-like peptide 1 (GLP-1) exerts many actions that improve glycemic control. GLP-1 stimulates glucose-stimulated insulin secretion and protects β cells, while its extrapancreatic effects include cardioprotection, reduction of hepatic glucose production, and regulation of satiety. Although an appealing antidiabetic drug candidate, the rapid degradation of GLP-1 by dipeptidyl peptidase 4 (DPP-4) means that its therapeutic use is unfeasible, and this prompted the development of two main GLP-1 therapies: long-acting GLP-1 analogs and DPP-4 inhibitors. In this review, we focus on the pancreatic effects exerted by current GLP-1 derivatives used to treat diabetes. Based on the results from in vitro and in vivo studies in humans and animal models, we describe the specific actions of GLP-1 analogs on the synthesis, processing, and secretion of insulin, islet morphology, and β cell proliferation and apoptosis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantitative Evaluation of Compliance with Recommendation for Sulfonylurea Dose Co-Administered with DPP-4 Inhibitors in Japan

PubMed Central

Kimura, Tomomi; Shiosakai, Kazuhito; Takeda, Yasuaki; Takahashi, Shinji; Kobayashi, Masahiko; Sakaguchi, Motonobu

2012-01-01

After the launch of dipeptidyl peptidase-4 (DPP-4), a new oral hypoglycemic drug (OHD), in December 2009, severe hypoglycemia cases were reported in Japan. Although the definite cause was unknown, co-administration with sulfonylureas (SU) was suspected as one of the potential risk factors. The Japan Association for Diabetes Education and Care (JADEC) released a recommendation in April 2010 to lower the dose of three major SUs (glimepiride, glibenclamide, and gliclazide) when adding a DPP-4 inhibitor. To evaluate the effectiveness of this risk minimization action along with labeling changes, dispensing records for 114,263 patients prescribed OHDs between December 2008 and December 2010 were identified in the Nihon-Chouzai pharmacy claims database. The adherence to the recommended dosing of SU co-prescribed with DPP-4 inhibitors increased from 46.3% before to 63.8% after the JADEC recommendation (p < 0.01 by time-series analysis), while no change was found in those for SU monotherapy and SU with other OHD co-prescriptions. The adherence was significantly worse for those receiving a glibenclamide prescription. The JADEC recommendation, along with labeling changes, appeared to have a favorable effect on the risk minimization action in Japan. In these instances, a pharmacy claims database can be a useful tool to evaluate risk minimization actions. PMID:24300302

Differential effects of PPAR-{gamma} activation versus chemical or genetic reduction of DPP-4 activity on bone quality in mice.

PubMed

Kyle, Kimberly A; Willett, Thomas L; Baggio, Laurie L; Drucker, Daniel J; Grynpas, Marc D

2011-02-01

Patients with type 2 diabetes mellitus have an increased risk of fracture that can be further exacerbated by thiazolidinediones. A new class of antidiabetic agents control glucose through reduction of dipeptidyl peptidase-4 (DPP-4) activity; however the importance of DPP-4 for the control of bone quality has not been extensively characterized. We compared the effects of the thiazolidinedione pioglitazone and the DPP-4 inhibitor sitagliptin on bone quality in high-fat diet (HFD)-fed wild-type mice. In complementary studies, we examined bone quality in Dpp4(+/+) vs. Dpp4(-/-) mice. Pioglitazone produced yellow bones with greater bone marrow adiposity and significantly reduced vertebral bone mechanics in male, female, and ovariectomized (OVX) HFD fed female mice. Pioglitazone negatively affected vertebral volumetric bone mineral density, trabecular architecture, and mineral apposition rate in male mice. Sitagliptin treatment of HFD-fed wild-type mice significantly improved vertebral volumetric bone mineral density and trabecular architecture in female mice, but these improvements were lost in females after OVX. Genetic inactivation of Dpp4 did not produce a major bone phenotype in male and female Dpp4(-/-) mice; however, OVX Dpp4(-/-) mice exhibited significantly reduced femoral size and mechanics. These findings delineate the skeletal consequences of pharmacological and genetic reduction of DPP-4 activity and reveal significant differences in the effects of pioglitazone vs. sitagliptin vs. genetic Dpp4 inactivation on bone mechanics in mice.

Pyroptosis and Apoptosis Pathways Engage in Bidirectional Crosstalk in Monocytes and Macrophages.

PubMed

Taabazuing, Cornelius Y; Okondo, Marian C; Bachovchin, Daniel A

2017-04-20

Pyroptosis is a lytic form of programmed cell death mediated by the inflammatory caspase-1, -4, and -5. We recently discovered that small-molecule inhibitors of the serine peptidases DPP8 and DPP9 (DPP8/9) induce pro-caspase-1-dependent pyroptosis in monocytes and macrophages. Notably, DPP8/9 inhibitors, unlike microbial agents, absolutely require caspase-1 to induce cell death. Therefore, DPP8/9 inhibitors are useful probes to study caspase-1 in cells. Here, we show that, in the absence of the pyroptosis-mediating substrate gasdermin D (GSDMD), caspase-1 activates caspase-3 and -7 and induces apoptosis, demonstrating that GSDMD is the only caspase-1 substrate that induces pyroptosis. Conversely, we found that, during apoptosis, caspase-3/-7 specifically block pyroptosis by cleaving GSDMD at a distinct site from the inflammatory caspases that inactivates the protein. Overall, this work reveals bidirectional crosstalk between apoptosis and pyroptosis in monocytes and macrophages, further illuminating the complex interplay between cell death pathways in the innate immune system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Discovery and structure-activity relationships of piperidinone- and piperidine-constrained phenethylamines as novel, potent, and selective dipeptidyl peptidase IV inhibitors.

PubMed

Pei, Zhonghua; Li, Xiaofeng; von Geldern, Thomas W; Longenecker, Kenton; Pireh, Daisy; Stewart, Kent D; Backes, Bradley J; Lai, Chunqiu; Lubben, Thomas H; Ballaron, Stephen J; Beno, David W A; Kempf-Grote, Anita J; Sham, Hing L; Trevillyan, James M

2007-04-19

Dipeptidyl peptidase IV (DPP4) inhibitors are emerging as a new class of therapeutic agents for the treatment of type 2 diabetes. They exert their beneficial effects by increasing the levels of active glucagon-like peptide-1 and glucose-dependent insulinotropic peptide, which are two important incretins for glucose homeostasis. Starting from a high-throughput screening hit, we were able to identify a series of piperidinone- and piperidine-constrained phenethylamines as novel DPP4 inhibitors. Optimized compounds are potent, selective, and have good pharmacokinetic profiles.

Efficacy and safety of ipragliflozin as add-on therapy to insulin in Japanese patients with type 2 diabetes mellitus (IOLITE): a multi-centre, randomized, placebo-controlled, double-blind study.

PubMed

Ishihara, Hisamitsu; Yamaguchi, Susumu; Nakao, Ikko; Okitsu, Akira; Asahina, Seitaro

2016-12-01

To examine the efficacy and safety of add-on ipragliflozin in Japanese patients with type 2 diabetes in the early stage of insulin therapy. Patients treated with insulin (bolus component <30% of total daily dose) with/without a dipeptidyl peptidase-4 (DPP-4) inhibitor were randomized to receive placebo (n = 87) or ipragliflozin (n = 175) for 16 weeks. The primary endpoint was the change in glycated haemoglobin (HbA1c) from baseline. Secondary endpoints included changes in fasting plasma glucose (FPG) and metabolic hormones. Safety endpoints were also examined. The changes in HbA1c were 0.27% and -0.79% (2.9 and -8.7 mmol/mol) in the placebo and ipragliflozin groups, respectively (baseline: 8.62% vs 8.67% [70.8 vs 71.2 mmol/mol]), corresponding to an adjusted mean difference of -1.07% (95% confidence interval -1.24, -0.91) or -11.7 mmol/mol (-13.5, -9.9), p < .001. Ipragliflozin reduced FPG and serum C-peptide levels and body weight (all p < .001), and increased serum adiponectin levels (p = .022). There was a statistically significant interaction for use/non-use of a DPP-4 inhibitor × treatment group for the change in HbA1c (p = .042). Hypoglycaemia was the only treatment-related adverse event reported in >5% of patients (14.9% vs 29.1%). Events consistent with urinary tract infection (placebo 1.1% vs ipragliflozin 2.3%) or genital infection (0.0% and 4.0%, respectively) occurred in <5% of patients. Ipragliflozin was well tolerated and effective in insulin-treated patients, especially when used with a DPP-4 inhibitor. © 2016 John Wiley & Sons Ltd.

Identification of Novel Human Dipeptidyl Peptidase-IV Inhibitors of Natural Origin (Part II): In Silico Prediction in Antidiabetic Extracts

PubMed Central

Guasch, Laura; Sala, Esther; Ojeda, María José; Valls, Cristina; Bladé, Cinta; Mulero, Miquel; Blay, Mayte; Ardévol, Anna; Garcia-Vallvé, Santiago; Pujadas, Gerard

2012-01-01

Background Natural extracts play an important role in traditional medicines for the treatment of diabetes mellitus and are also an essential resource for new drug discovery. Dipeptidyl peptidase IV (DPP-IV) inhibitors are potential candidates for the treatment of type 2 diabetes mellitus, and the effectiveness of certain antidiabetic extracts of natural origin could be, at least partially, explained by the inhibition of DPP-IV. Methodology/Principal Findings Using an initial set of 29,779 natural products that are annotated with their natural source and an experimentally validated virtual screening procedure previously developed in our lab (Guasch et al.; 2012) [1], we have predicted 12 potential DPP-IV inhibitors from 12 different plant extracts that are known to have antidiabetic activity. Seven of these molecules are identical or similar to molecules with described antidiabetic activity (although their role as DPP-IV inhibitors has not been suggested as an explanation for their bioactivity). Therefore, it is plausible that these 12 molecules could be responsible, at least in part, for the antidiabetic activity of these extracts through their inhibitory effect on DPP-IV. In addition, we also identified as potential DPP-IV inhibitors 6 molecules from 6 different plants with no described antidiabetic activity but that share the same genus as plants with known antidiabetic properties. Moreover, none of the 18 molecules that we predicted as DPP-IV inhibitors exhibits chemical similarity with a group of 2,342 known DPP-IV inhibitors. Conclusions/Significance Our study identified 18 potential DPP-IV inhibitors in 18 different plant extracts (12 of these plants have known antidiabetic properties, whereas, for the remaining 6, antidiabetic activity has been reported for other plant species from the same genus). Moreover, none of the 18 molecules exhibits chemical similarity with a large group of known DPP-IV inhibitors. PMID:23028712

Dipeptidyl Peptidase-4 Inhibitor Use is Associated with Decreased Risk of Fracture in Patients with Type 2 Diabetes: A Population-Based Cohort Study.

PubMed

Hou, Wen-Hsuan; Chang, Kai-Cheng; Li, Chung-Yi; Ou, Huang-Tz

2018-05-16

To investigate the putative link between dipeptidyl peptidase-4 inhibitor (DPP-4i) use and the risk of fracture in patients with type 2 diabetes. This propensity-score-matched population-based cohort study was performed between 2009 and 2013 on patients with type 2 diabetes who were stable metformin users. A total of 3,996 patients with type 2 diabetes used DPP-4i as a second-line antidiabetic drug. The same number of matched non-DPP-4i users were followed up until fracture occurrence, health insurance policy termination, or the end of 2013. The incidence rates of overall and cause-specific fractures were estimated based on the Poisson assumption. A multiple Cox proportional hazard model was used to estimate the covariate-adjusted hazard ratio (HR) and 95% confidence interval (CI) to determine the association between DPP-4i use and overall and cause-specific fractures stratified by age and sex. Over a maximum follow-up period of 5 years, 340 DPP-4i users and 419 non-DPP-4i users were newly diagnosed with fractures, yielding incidence rates of 28.03 and 32.04 per 1,000 people per year, respectively. The Cox proportional hazard model revealed that DPP-4i use significantly reduced the risk of all-cause fractures and upper extremity fractures, with adjusted HRs of 0.86 (95% CI: 0.74-0.99) and 0.75 (95% CI: 0.59-0.95), respectively. The aforementioned associations of DDP-4i use with fracture were sustained across sex and age stratifications. The results of this study supported the premise that DPP-4i usage is associated with a reduced risk of all-cause fractures and upper extremity fractures in patients with type 2 diabetes. This article is protected by copyright. All rights reserved.

Dipeptidyl Peptidase-4 Inhibitors and Heart Failure Exacerbation in the Veteran Population: An Observational Study.

PubMed

Cobretti, Michael R; Bowman, Benjamin; Grabarczyk, Ted; Potter, Emily

2018-03-01

The dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors) are effective modulators of fasting and postprandial hyperglycemia in patients with type 2 diabetes mellitus (T2DM). In 2013 the Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus-Thrombolysis in Myocardial Infarction 53 (SAVOR-TIMI 53) clinical trial found an increased risk of heart failure exacerbation, as a secondary outcome, among patients treated with saxagliptin. This study examines the safety of DPP-4 inhibitors as a class in T2DM in relation to risk of heart failure exacerbations. Retrospective cohort study of two groups of patients using data from the national Department of Veteran's Affairs (VA) Health Care System: patients initially prescribed DPP-4 inhibitors with or without second-generation sulfonylureas and/or metformin (exposed group) compared with patients initially prescribed only second-generation sulfonylureas and/or metformin (unexposed group) between August 1, 2013, and August 30, 2016. The primary aim of this study was to determine the difference in 1-year heart failure exacerbation rate in patients with T2DM between the exposed and unexposed groups. Data were analyzed using the χ 2 Student t test and Kaplan-Meier analysis. Significance was set at p<0.05. The study evaluated 672,265 patients: 33,614 patients in the exposed group and 638,651 patients in the unexposed group. Overall, 130 (0.38%) heart failure exacerbations were documented in the exposed group, and 2222 (0.34%) heart failure exacerbations were documented in the unexposed group; the difference in exacerbation rate was nonsignificant between groups (p=0.24). In a subgroup analysis of patients with a baseline diagnosis of heart failure, the difference in rate of heart failure exacerbations remained nonsignificant (p=0.334). Patients in the veteran population with T2DM treated with DPP-4 inhibitors did not demonstrate a significant increase in risk for heart failure exacerbation, regardless of whether a patient had been previously diagnosed with heart failure. This finding potentially supports safe usage of DPP-4 inhibitors in this patient population regardless of heart failure diagnosis. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

A review of the efficacy and safety of oral antidiabetic drugs

PubMed Central

Stein, Stephanie Aleskow; Lamos, Elizabeth Mary; Davis, Stephen N

2014-01-01

Introduction Additional oral antidiabetic agents to metformin, sulfonylureas (SU) and thiazolidinediones (TZD) are approved for the treatment of type 2 diabetes. Areas covered The efficacy and safety of metformin, SUs, TZDs, dipeptidyl peptidase-IV (DPP-4) inhibitors, meglitinide analogs, α-glucosidase inhibitors (AGIs), bile-acid sequestrants (BAS) and bromocriptine will be reviewed. Expert opinion Several new oral agents have been approved for type 2 diabetes management in recent years. It is important to understand the efficacy and safety of these medications in addition to the older agents to best maximize oral drug therapy for diabetes. Of the recently introduced oral hypoglycemic/antihyperglycemic agents, the DPP-4 inhibitors are moderately efficacious compared with mainstay treatment with metformin with a low side-effect profile and have good efficacy in combination with other oral agents and insulin. They are a recommended alternative when metformin use is limited by gastrointestinal (GI) side effects or when SU treatment results in significant hypoglycemia or weight gain. Meglitinide analogs are limited by their frequent dosing, expense and hypoglycemia (repaglinide > nateglinide), while AGIs are also limited by their dosing schedule and GI side-effect profile. BAS and bromocriptine have the lowest efficacy with regard to HbA1c reduction, also are plagued by GI adverse reactions, but have a low risk of hypoglycemia. PMID:23241069

Effect of dipeptidyl peptidase-4 inhibition on circadian blood pressure during the development of salt-dependent hypertension in rats

PubMed Central

Sufiun, Abu; Rafiq, Kazi; Fujisawa, Yoshihide; Rahman, Asadur; Mori, Hirohito; Nakano, Daisuke; Kobori, Hiroyuki; Ohmori, Koji; Masaki, Tsutomu; Kohno, Masakazu; Nishiyama, Akira

2015-01-01

A growing body of evidence has indicated that dipeptidyl peptidase-4 (DPP-4) inhibitors have antihypertensive effects. Here, we aim to examine the effect of vildagliptin, a DPP-4-specific inhibitor, on blood pressure and its circadian-dipping pattern during the development of salt-dependent hypertension in Dahl salt-sensitive (DSS) rats. DSS rats were treated with a high-salt diet (8% NaCl) plus vehicle or vildagliptin (3 or 10 mg kg−1 twice daily by oral gavage) for 7 days. Blood pressure was measured by the telemetry system. High-salt diet for 7 days significantly increased the mean arterial pressure (MAP), systolic blood pressure (SBP) and were also associated with an extreme dipping pattern of blood pressure in DSS rats. Treatment with vildagliptin dose-dependently decreased plasma DPP-4 activity, increased plasma glucagon-like peptide 1 (GLP-1) levels and attenuated the development of salt-induced hypertension. Furthermore, vildagliptin significantly increased urine sodium excretion and normalized the dipping pattern of blood pressure. In contrast, intracerebroventricular infusion of vildagliptin (50, 500 or 2500 μg) did not alter MAP and heart rate in DSS rats. These data suggest that salt-dependent hypertension initially develops with an extreme blood pressure dipping pattern. The DPP-4 inhibitor, vildagliptin, may elicit beneficial antihypertensive effects, including the improvement of abnormal circadian blood pressure pattern, by enhancing urinary sodium excretion. PMID:25588850

The cardiovascular safety trials of DPP-4 inhibitors, GLP-1 agonists, and SGLT2 inhibitors.

PubMed

Secrest, Matthew H; Udell, Jacob A; Filion, Kristian B

2017-04-01

In this paper, we review the results of large, double-blind, placebo-controlled randomized trials mandated by the US Food and Drug Administration to examine the cardiovascular safety of newly-approved antihyperglycemic agents in patients with type 2 diabetes. The cardiovascular effects of dipeptidyl peptidase-4 (DPP-4) inhibitors remain controversial: while these drugs did not reduce or increase the risk of primary, pre-specified composite cardiovascular outcomes, one DPP-4 inhibitor (saxagliptin) increased the risk of hospitalization for heart failure in the overall population; another (alogliptin) demonstrated inconsistent effects on heart failure hospitalization across subgroups of patients, and a third (sitagliptin) demonstrated no effect on heart failure. Evidence for cardiovascular benefits of glucagon-like peptide-1 (GLP-1) agonists has been similarly heterogeneous, with liraglutide and semaglutide reducing the risk of composite cardiovascular outcomes, but lixisenatide having no reduction or increase in cardiovascular risk. The effect of GLP-1 agonists on retinopathy remains a potential concern. In the only completed trial to date to assess a sodium-glucose cotransporter-2 (SGLT2) inhibitor, empagliflozin reduced the risk of composite cardiovascular endpoints, predominantly through its impact on cardiovascular mortality and heart failure hospitalization. Copyright © 2017 Elsevier Inc. All rights reserved.

Anti-Inflammatory Action of Sitagliptin and Linagliptin in Doxorubicin Nephropathy.

PubMed

Jo, Chor Ho; Kim, Sua; Park, Joon-Sung; Kim, Gheun-Ho

2018-06-15

Dipeptidyl peptidase-4 (DPP4) inhibitors are known to have a protective effect on diabetic kidney disease, possibly via reduction of oxidative stress and inflammation in the kidney. However, whether these potential mechanisms play a role in non-diabetic proteinuric kidney diseases is not clear. Two different animal experiments were carried out using sitagliptin and linagliptin for DPP4 inhibition. In each experiment, male Sprague-Dawley rats were uninephrectomized and randomly divided into vehicle-treated and doxorubicin-treated rats, with or without DPP4 inhibition. Administration of a DPP4 inhibitor was performed daily by oral gavage over six weeks. A single intravenous injection of doxorubicin resulted in hypertension and remarkable proteinuria. Linagliptin, but not sitagliptin, lowered systolic blood pressure in rats with doxorubicin nephropathy. By contrast, sitagliptin ameliorated tubulointerstitial injury, inflammatory cell infiltration, and interstitial fibrosis in rat kidneys with doxorubicin nephropathy. Quantitative polymerase chain reaction analysis revealed that mRNA expression of NLRP3, caspase-1, ASC, and IL-1β was remarkably increased in rat kidneys with doxorubicin nephropathy, and that this upregulation of the major components of the NLRP3 inflammasome was effectively suppressed by treatment with either sitagliptin or linagliptin. Additionally, upregulation of IL-6 was reversed by linagliptin, but not by sitagliptin. On the other hand, sitagliptin, but not linagliptin, reversed the increase in mRNA expression of gp91phox, p47phox, and p67phox in rat kidneys with doxorubicin nephropathy. NLRP3 inflammasome activation was shown in our rat model of doxorubicin nephropathy. DPP4 inhibitors can suppress the activity of NLRP3, with or without relieving NADPH oxidase 2-related oxidative stress. © 2018 The Author(s). Published by S. Karger AG, Basel.

Cardiovascular pleiotropic actions of DPP-4 inhibitors: a step at the cutting edge in understanding their additional therapeutic potentials.

PubMed

Balakumar, Pitchai; Dhanaraj, Sokkalingam A

2013-09-01

Dipeptidyl peptidase 4 (DPP-4) is a serine protease enzyme expressed widely in many tissues, including the cardiovascular system. The incretin hormones such as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are released from the small intestine into the vasculature during a meal, and these incretins have a potential to release insulin from pancreatic beta cells of islets of Langerhans, affording a glucose-lowering action. However, both incretins are hurriedly degraded by the DPP-4. Inhibitors of DPP-4, therefore, enhance the bioavailability of GLP-1 and GIP, and thus have been approved for better glycemic management in patients afflicted with type 2 diabetes mellitus (T2DM). Five different DPP-4 inhibitors, often called as 'gliptins', namely sitagliptin, vildagliptin, saxagliptin, linagliptin and alogliptin have been approved hitherto for clinical use. These drugs are used along with diet and exercise to lower blood sugar in diabetic subjects. T2DM is intricately related with an increased risk of cardiovascular disease. Growing body of evidence suggests that gliptins, in addition to their persuasive anti-diabetic action, have a beneficial pleiotropic action on the heart and vessels. In view of the fact of cardiovascular disease susceptibility of patients afflicted with T2DM, gliptins might offer additional therapeutic benefits in treating diabetic cardiovascular complications. Exploring further the cardiovascular pleiotropic potentials of gliptins might open a panorama in impeccably employing these agents for the dual management of T2DM and T2DM-associated perilous cardiovascular complications. This review will shed lights on the newly identified beneficial pleiotropic actions of gliptins on the cardiovascular system. Copyright © 2013 Elsevier Inc. All rights reserved.

Comparison of costs and outcomes of dapagliflozin with other glucose-lowering therapy classes added to metformin using a short-term cost-effectiveness model in the US setting.

PubMed

Chakravarty, Abhiroop; Rastogi, Mohini; Dhankhar, Praveen; Bell, Kelly F

2018-05-01

To compare 1-year costs and benefits of dapagliflozin (DAPA), a sodium-glucose cotransporter-2 (SGLT-2) inhibitor, with those of other treatments for type 2 diabetes (T2D), such as glucagon-like peptide-1 receptor agonists (GLP-1RAs), sulfonylureas (SUs), thiazolidinediones (TZDs), and dipeptidyl peptidase-4 inhibitors (DPP-4i), all combined with metformin. A short-term decision-analytic model with a 1-year time horizon was developed from a payer's perspective in the United States setting. Costs and benefits associated with four clinical end-points (glycated hemoglobin [A1C], body weight, systolic blood pressure [SBP], and risk of hypoglycemia) were evaluated in the analysis. The impact of DAPA and other glucose-lowering therapy classes on these clinical end-points was estimated from a network meta-analysis (NMA). Data for costs and quality-adjusted life-years (QALYs) associated with a per-unit change in these clinical end-points were taken from published literature. Drug prices were taken from an annual wholesale price list. All costs were inflation-adjusted to December 2016 costs using the medical care component of the consumer price index. Total costs (both medical and drug costs), total QALYs, and incremental cost-effectiveness ratios (ICERs) were estimated. Sensitivity analyses (SA) were performed to explore uncertainty in the inputs. To assess face validity, results from the short-term model were compared with long-term models published for these drugs. The total annual medical cost for DAPA was less than that for GLP-1RA ($186 less), DPP-4i ($1,142 less), SU ($2,474 less), and TZD ($1,640 less). Treatment with DAPA resulted in an average QALY gain of 0.0107, 0.0587, 0.1137, and 0.0715 per treated patient when compared with GLP-1RA, DPP-4i, SU, and TZD, respectively. ICERs for DAPA vs SU and TZD were $19,005 and $25,835, respectively. DAPA was a cost-saving option when compared with GLP-1RAs and DPP-4is. Among all four clinical end-points, change in weight had the greatest impact on total annual costs and ICERS. Sensitivity analysis showed that results were robust, and results from the short-term model were found to be similar to those of published long-term models. This analysis showed that DAPA was cost-saving compared with GLP-1RA and DPP-4i, and cost-effective compared with SU and TZD in the US setting over 1 year. Furthermore, the results suggest that, among the four composite clinical end-points, change in weight and SBP had an impact on cost-effectiveness results.

Reduction of serum FABP4 level by sitagliptin, a DPP-4 inhibitor, in patients with type 2 diabetes mellitus[S

PubMed Central

Furuhashi, Masato; Hiramitsu, Shinya; Mita, Tomohiro; Fuseya, Takahiro; Ishimura, Shutaro; Omori, Akina; Matsumoto, Megumi; Watanabe, Yuki; Hoshina, Kyoko; Tanaka, Marenao; Moniwa, Norihito; Yoshida, Hideaki; Ishii, Junnichi; Miura, Tetsuji

2015-01-01

Fatty acid binding protein 4 (FABP4), also known as adipocyte FABP or aP2, is secreted from adipocytes in association with lipolysis as a novel adipokine, and elevated serum FABP4 level is associated with obesity, insulin resistance, and atherosclerosis. However, little is known about the modulation of serum FABP4 level by therapeutic drugs. Sitagliptin (50 mg/day), a dipeptidyl peptidase 4 (DPP-4) inhibitor that increases glucagon-like peptide 1 (GLP-1), was administered to patients with type 2 diabetes (n = 24) for 12 weeks. Treatment with sitagliptin decreased serum FABP4 concentration by 19.7% (17.8 ± 1.8 vs. 14.3 ± 1.5 ng/ml, P < 0.001) and hemoglobin A1c without significant changes in adiposity or lipid variables. In 3T3-L1 adipocytes, sitagliptin or exendin-4, a GLP-1 receptor agonist, had no effect on short-term (2 h) secretion of FABP4. However, gene expression and long-term (24 h) secretion of FABP4 were significantly reduced by sitagliptin, which was not mimicked by exendin-4. Treatment with recombinant DPP-4 increased gene expression and long-term secretion of FABP4, and the effects were cancelled by sitagliptin. Furthermore, knockdown of DPP-4 in 3T3-L1 adipocytes decreased gene expression and long-term secretion of FABP4. In conclusion, sitagliptin decreases serum FABP4 level, at least in part, via reduction in the expression and consecutive secretion of FABP4 in adipocytes by direct inhibition of DPP-4. PMID:26467280

Inhibition of dipeptidyl-peptidase IV catalyzed peptide truncation by Vildagliptin ((2S)-{[(3-hydroxyadamantan-1-yl)amino]acetyl}-pyrrolidine-2-carbonitrile).

PubMed

Brandt, Inger; Joossens, Jurgen; Chen, Xin; Maes, Marie-Berthe; Scharpé, Simon; De Meester, Ingrid; Lambeir, Anne-Marie

2005-07-01

Vildagliptin (NVP-LAF237/(2S)-{[(3-hydroxyadamantan-1-yl)amino]acetyl}-pyrrolidine-2-carbonitrile) was described as a potent, selective and orally bio-available dipeptidyl-peptidase IV (DPP IV, EC 3.4.14.5) inhibitor [Villhauer EB, Brinkman JA, Naderi GB, Burkey BF, Dunning BE, Prasad K, et al.1-[[(3-Hydroxy-1-adamantyl)amino]acetyl]-2-cyano-(S)-pyrrolidine: a potent, selective, and orally bioavailable dipeptidyl peptidase IV inhibitor with antihyperglycemic properties. J Med Chem 2003;46:2774-89]. Phase III clinical trials for the use of this compound in the treatment of Type 2 diabetes were started in the first quarter of 2004. In this paper, we report on (1) the kinetics of binding, (2) the type of inhibition, (3) the selectivity with respect to other peptidases, and (4) the inhibitory potency on the DPP IV catalyzed degradation of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and substance P. Vildagliptin behaved as a slow-binding DPP IV inhibitor with an association rate constant of 1.4x10(5)M(-1)s(-1) and a K(i) of 17nM. It is a micromolar inhibitor for dipeptidyl-peptidase 8 and does not significantly inhibit dipeptidyl-peptidase II (EC 3.4.11.2), prolyl oligopeptidase (EC 3.4.21.26), aminopeptidase P (EC 3.4.11.9) or aminopeptidase M (EC 3.4.11.2). There was no evidence for substrate specific inhibition of DPP IV by Vildagliptin or for important allosteric factors affecting the inhibition constant in presence of GIP and GLP-1.

Effects of Inhibiting Dipeptidyl Peptidase-4 (DPP4) in Cows with Subclinical Ketosis.

PubMed

Schulz, Kirsten; Frahm, Jana; Kersten, Susanne; Meyer, Ulrich; Rehage, Jürgen; Piechotta, Marion; Meyerholz, Maria; Breves, Gerhard; Reiche, Dania; Sauerwein, Helga; Dänicke, Sven

2015-01-01

The inhibition of dipeptidyl peptidase-4 (DPP4) via specific inhibitors is known to result in improved glucose tolerance and insulin sensitivity and decreased accumulation of hepatic fat in type II diabetic human patients. The metabolic situation of dairy cows can easily be compared to the status of human diabetes and non-alcoholic fatty liver. For both, insulin sensitivity is reduced, while hepatic fat accumulation increases, characterized by high levels of non-esterified fatty acids (NEFA) and ketone bodies.Therefore, in the present study, a DPP4 inhibitor was employed (BI 14332) for the first time in cows. In a first investigation BI 14332 treatment (intravenous injection at dosages of up to 3 mg/kg body weight) was well tolerated in healthy lactating pluriparous cows (n = 6) with a significant inhibition of DPP4 in plasma and liver. Further testing included primi- and pluriparous lactating cows suffering from subclinical ketosis (β-hydroxybutyrate concentrations in serum > 1.2 mM; n = 12). The intension was to offer effects of DPP4 inhibition during comprehensive lipomobilisation and hepatosteatosis. The cows of subclinical ketosis were evenly allocated to either the treatment group (daily injections, 0.3 mg BI 14332/kg body weight, 7 days) or the control group. Under condition of subclinical ketosis, the impact of DPP4 inhibition via BI 14332 was less, as in particular β-hydroxybutyrate and the hepatic lipid content remained unaffected, but NEFA and triglyceride concentrations were decreased after treatment. Owing to lower NEFA, the revised quantitative insulin sensitivity check index (surrogate marker for insulin sensitivity) increased. Therefore, a positive influence on energy metabolism might be quite possible. Minor impacts on immune-modulating variables were limited to the lymphocyte CD4+/CD8+ ratio for which a trend to decreased values in treated versus control animals was noted. In sum, the DPP4 inhibition in cows did not affect glycaemic control like it is shown in humans, but was able to impact hyperlipemia, as NEFA and TG decreased.

Identifying neuropeptide Y (NPY) as the main stress-related substrate of dipeptidyl peptidase 4 (DPP4) in blood circulation.

PubMed

Wagner, Leona; Kaestner, Florian; Wolf, Raik; Stiller, Harald; Heiser, Ulrich; Manhart, Susanne; Hoffmann, Torsten; Rahfeld, Jens-Ulrich; Demuth, Hans-Ulrich; Rothermundt, Matthias; von Hörsten, Stephan

2016-06-01

Dipeptidyl peptidase 4 (DPP4; EC 3.4.14.5; CD26) is a membrane-bound or shedded serine protease that hydrolyzes dipeptides from the N-terminus of peptides with either proline or alanine at the penultimate position. Substrates of DPP4 include several stress-related neuropeptides implicated in anxiety, depression and schizophrenia. A decline of DPP4-like activity has been reported in sera from depressed patient, but not fully characterized regarding DPP4-like enzymes, therapeutic interventions and protein. Sera from 16 melancholic- and 16 non-melancholic-depressed patients were evaluated for DPP4-like activities and the concentration of soluble DPP4 protein before and after treatment by anti-depressive therapies. Post-translational modification of DPP4-isoforms and degradation of NPY, Peptide YY (PYY), Galanin-like peptide (GALP), Orexin B (OrxB), OrxA, pituitary adenylate cyclase-activating polypeptide (PACAP) and substance P (SP) were studied in serum and in ex vivo human blood. N-terminal truncation of biotinylated NPY by endothelial membrane-bound DPP4 versus soluble DPP4 was determined in rat brain perfusates and spiked sera. Lower DPP4 activities in depressed patients were reversed by anti-depressive treatment. In sera, DPP4 contributed to more than 90% of the overall DPP4-like activity and correlated with its protein concentration. NPY displayed equal degradation in serum and blood, and was equally truncated by serum and endothelial DPP4. In addition, GALP and rat OrxB were identified as novel substrates of DPP4. NPY is the best DPP4-substrate in blood, being truncated by soluble and membrane DPP4, respectively. The decline of soluble DPP4 in acute depression could be reversed upon anti-depressive treatment. Peptidases from three functional compartments regulate the bioactivity of NPY in blood. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment choices for the glycaemic management of patients with type 2 diabetes and chronic kidney disease: Analysis of the SAIL patient linked dataset.

PubMed

Min, Thinzar; Davies, Gareth I; Rice, Sam; Chess, James; Stephens, Jeffrey W

Chronic kidney disease (CKD) is common in type 2 diabetes and limits the treatment choices for glycaemic control. Our aim was to examine real-world prescribing for managing hyperglycaemia in the presence of CKD. The SAIL (Secure Anonymised Information Linkage) databank was used to examine prescribing during the period from the 1st of January to 30th December 2014. CKD was defined as:- none or mild CKD, eGFR ≥60mL/min/1.73m 2 ; moderate CKD eGFR <60mL/min/1.73m 2 ; and severe CKD eGFR <30mL/min/1.73m 2 or requiring dialysis. We identified 9585 subjects who received any form of glucose lowering therapy (8363 had no/mild CKD; 1137 moderate CKD; 85 severe CKD). There was a linear association between insulin use and CKD severity with approximately 54% of those with severe CKD receiving insulin. Sulphonylureas use did not differ among the CKD groups and was approximately 40%. Metformin showed a linear decrease across the groups, however approximately 21% in the severe CKD group received metformin. The use of dipeptidyl peptidase 4 inhibitors (DPP-4i) was approximately 20% and did not differ among groups. The DPP-4 inhibitor choice was:- 1% vildagliptin, 9% saxagliptin, 58% sitagliptin, and 32% linaglitpin. With respect to sitagliptin and saxagliptin, 72% and 62% received an inappropriately high dose in the setting of CKD. We observed that a considerable proportion of patients with type 2 diabetes and CKD were receiving metformin and non dose-adjusted DPP-4 inhibitors. Careful consideration of medication use and dosaging is required in the setting of CKD and type 2 diabetes. Copyright © 2017 Diabetes India. Published by Elsevier Ltd. All rights reserved.

Cardiac DPP-4 inhibition by saxagliptin ameliorates isoproterenol-induced myocardial remodeling and cardiac diastolic dysfunction in rats.

PubMed

Ikeda, Junichi; Kimoto, Naoya; Kitayama, Tetsuya; Kunori, Shunji

2016-09-01

Saxagliptin, a potent and selective DPP-4 inhibitor, is characterized by its slow dissociation from DPP-4 and its long half-life and is expected to have a potent tissue membrane-bound DPP-4-inhibitory effect in various tissues. In the present study, we examined the effects of saxagliptin on in situ cardiac DPP-4 activity. We also examined the effects of saxagliptin on isoproterenol-induced the changes in the early stage such as, myocardial remodeling and cardiac diastolic dysfunction. Male SD rats treated with isoproterenol (1 mg/kg/day via osmotic pump) received vehicle or saxagliptin (17.5 mg/kg via drinking water) for 2 weeks. In situ cardiac DPP-4 activity was measured by a colorimetric assay. Cardiac gene expressions were examined and an echocardiographic analysis was performed. Saxagliptin treatment significantly inhibited in situ cardiac DPP-4 activity and suppressed isoproterenol-induced myocardial remodeling and the expression of related genes without altering the blood glucose levels. Saxagliptin also significantly ameliorated cardiac diastolic dysfunction in isoproterenol-treated rats. In conclusion, the inhibition of DPP-4 activity in cardiac tissue by saxagliptin was associated with suppression of myocardial remodeling and cardiac diastolic dysfunction independently of its glucose-lowering action in isoproterenol-treated rats. Cardiac DPP-4 activity may contribute to myocardial remodeling in the development of heart failure. Copyright © 2016 Kyowa Hakko Kirin Co.,Ltd. Production and hosting by Elsevier B.V. All rights reserved.

Pyrrolidine-constrained phenethylamines: The design of potent, selective, and pharmacologically efficacious dipeptidyl peptidase IV (DPP4) inhibitors from a lead-like screening hit.

PubMed

Backes, Bradley J; Longenecker, Kenton; Hamilton, Gregory L; Stewart, Kent; Lai, Chunqiu; Kopecka, Hana; von Geldern, Thomas W; Madar, David J; Pei, Zhonghua; Lubben, Thomas H; Zinker, Bradley A; Tian, Zhenping; Ballaron, Stephen J; Stashko, Michael A; Mika, Amanda K; Beno, David W A; Kempf-Grote, Anita J; Black-Schaefer, Candace; Sham, Hing L; Trevillyan, James M

2007-04-01

A novel series of pyrrolidine-constrained phenethylamines were developed as dipeptidyl peptidase IV (DPP4) inhibitors for the treatment of type 2 diabetes. The cyclohexene ring of lead-like screening hit 5 was replaced with a pyrrolidine to enable parallel chemistry, and protein co-crystal structural data guided the optimization of N-substituents. Employing this strategy, a >400x improvement in potency over the initial hit was realized in rapid fashion. Optimized compounds are potent and selective inhibitors with excellent pharmacokinetic profiles. Compound 30 was efficacious in vivo, lowering blood glucose in ZDF rats that were allowed to feed freely on a mixed meal.

The Effect of Sitagliptin on the Regression of Carotid Intima-Media Thickening in Patients with Type 2 Diabetes Mellitus: A Post Hoc Analysis of the Sitagliptin Preventive Study of Intima-Media Thickness Evaluation.

PubMed

Mita, Tomoya; Katakami, Naoto; Shiraiwa, Toshihiko; Yoshii, Hidenori; Gosho, Masahiko; Shimomura, Iichiro; Watada, Hirotaka

2017-01-01

Background. The effect of dipeptidyl peptidase-4 (DPP-4) inhibitors on the regression of carotid IMT remains largely unknown. The present study aimed to clarify whether sitagliptin, DPP-4 inhibitor, could regress carotid intima-media thickness (IMT) in insulin-treated patients with type 2 diabetes mellitus (T2DM). Methods . This is an exploratory analysis of a randomized trial in which we investigated the effect of sitagliptin on the progression of carotid IMT in insulin-treated patients with T2DM. Here, we compared the efficacy of sitagliptin treatment on the number of patients who showed regression of carotid IMT of ≥0.10 mm in a post hoc analysis. Results . The percentages of the number of the patients who showed regression of mean-IMT-CCA (28.9% in the sitagliptin group versus 16.4% in the conventional group, P  = 0.022) and left max-IMT-CCA (43.0% in the sitagliptin group versus 26.2% in the conventional group, P  = 0.007), but not right max-IMT-CCA, were higher in the sitagliptin treatment group compared with those in the non-DPP-4 inhibitor treatment group. In multiple logistic regression analysis, sitagliptin treatment significantly achieved higher target attainment of mean-IMT-CCA ≥0.10 mm and right and left max-IMT-CCA ≥0.10 mm compared to conventional treatment. Conclusions . Our data suggested that DPP-4 inhibitors were associated with the regression of carotid atherosclerosis in insulin-treated T2DM patients. This study has been registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN000007396).

Dipeptidyl peptidase 4 inhibitor attenuates obesity-induced myocardial fibrosis by inhibiting transforming growth factor-βl and Smad2/3 pathways in high-fat diet-induced obesity rat model.

PubMed

Hong, Seul-Ki; Choo, Eun-Ho; Ihm, Sang-Hyun; Chang, Kiyuk; Seung, Ki-Bae

2017-11-01

Obesity-induced myocardial fibrosis may lead to diastolic dysfunction and ultimately heart failure. Activation of the transforming growth factor (TGF)-βl and its downstream Smad2/3 pathways may play a pivotal role in the pathogenesis of obesity-induced myocardial fibrosis, and the antidiabetic dipeptidyl peptidase 4 inhibitors (DPP4i) might affect these pathways. We investigated whether DPP4i reduces myocardial fibrosis by inhibiting the TGF-β1 and Smad2/3 pathways in the myocardium of a diet-induced obesity (DIO) rat model. Eight-week-old male spontaneously hypertensive rats (SHRs) were fed either a normal fat diet (chow) or a high-fat diet (HFD) and then the HFD-fed SHRs were randomized to either the DPP4i (MK-0626) or control (distilled water) groups for 12weeks. At 20weeks old, all the rats underwent hemodynamic and metabolic studies and Doppler echocardiography. Compared with the normal fat diet (chow)-fed SHRs, the HFD-fed SHRs developed a more intense degree of hyperglycemia and dyslipidemia and showed a constellation of left ventricular (LV) diastolic dysfunction, and exacerbated myocardial fibrosis, as well as activation of the TGF-β1 and Smad2/3 pathways. DPP4i significantly improved the metabolic and hemodynamic parameters. The echocardiogram showed that DPP4i improved the LV diastolic dysfunction (early to late ventricular filling velocity [E/A] ratio, 1.49±0.21 vs. 1.77±0.09, p<0.05). Furthermore, DPP4i significantly reduced myocardial fibrosis and collagen production by the myocardium and suppressed TGF-β1 and phosphorylation of Smad2/3 in the heart. In addition, DPP4i decreased TGF-β1-induced collagen production and TGF-β1-mediated phosphorylation and nuclear translocation of Smad2/3 in rat cardiac fibroblasts. In conclusion, DPP4 inhibition attenuated myocardial fibrosis and improved LV diastolic dysfunction in a DIO rat model by modulating the TGF-β1 and Smad2/3 pathways. Copyright © 2017 Elsevier Inc. All rights reserved.

Structure activity relationship modelling of milk protein-derived peptides with dipeptidyl peptidase IV (DPP-IV) inhibitory activity.

PubMed

Nongonierma, Alice B; FitzGerald, Richard J

2016-05-01

Quantitative structure activity type models were developed in an attempt to predict the key features of peptide sequences having dipeptidyl peptidase IV (DPP-IV) inhibitory activity. The models were then employed to help predict the potential of peptides, which are currently reported in the literature to be present in the intestinal tract of humans following milk/dairy product ingestion, to act as inhibitors of DPP-IV. Two models (z- and v-scale) for short (2-5 amino acid residues) bovine milk peptides, behaving as competitive inhibitors of DPP-IV, were developed. The z- and the v-scale models (p<0.05, R(2) of 0.829 and 0.815, respectively) were then applied to 56 milk protein-derived peptides previously reported in the literature to be found in the intestinal tract of humans which possessed a structural feature of DPP-IV inhibitory peptides (P at the N2 position). Ten of these peptides were synthetized and tested for their in vitro DPP-IV inhibitory properties. There was no agreement between the predicted and experimentally determined DPP-IV half maximal inhibitory concentrations (IC50) for the competitive peptide inhibitors. However, the ranking for DPP-IV inhibitory potency of the competitive peptide inhibitors was conserved. Furthermore, potent in vitro DPP-IV inhibitory activity was observed with two peptides, LPVPQ (IC50=43.8±8.8μM) and IPM (IC50=69.5±8.7μM). Peptides present within the gastrointestinal tract of human may have promise for the development of natural DPP-IV inhibitors for the management of serum glucose. Copyright © 2016 Elsevier Inc. All rights reserved.

Dipeptidyl peptidase-4 inhibitors and risk of heart failure in type 2 diabetes: systematic review and meta-analysis of randomised and observational studies.

PubMed

Li, Ling; Li, Sheyu; Deng, Ke; Liu, Jiali; Vandvik, Per Olav; Zhao, Pujing; Zhang, Longhao; Shen, Jiantong; Bala, Malgorzata M; Sohani, Zahra N; Wong, Evelyn; Busse, Jason W; Ebrahim, Shanil; Malaga, German; Rios, Lorena P; Wang, Yingqiang; Chen, Qunfei; Guyatt, Gordon H; Sun, Xin

2016-02-17

To examine the association between dipeptidyl peptidase-4 (DPP-4) inhibitors and the risk of heart failure or hospital admission for heart failure in patients with type 2 diabetes. Systematic review and meta-analysis of randomised and observational studies. Medline, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov searched up to 25 June 2015, and communication with experts. Randomised controlled trials, non-randomised controlled trials, cohort studies, and case-control studies that compared DPP-4 inhibitors against placebo, lifestyle modification, or active antidiabetic drugs in adults with type 2 diabetes, and explicitly reported the outcome of heart failure or hospital admission for heart failure. Teams of paired reviewers independently screened for eligible studies, assessed risk of bias, and extracted data using standardised, pilot tested forms. Data from trials and observational studies were pooled separately; quality of evidence was assessed by the GRADE approach. Eligible studies included 43 trials (n=68,775) and 12 observational studies (nine cohort studies, three nested case-control studies; n=1,777,358). Pooling of 38 trials reporting heart failure provided low quality evidence for a possible similar risk of heart failure between DPP-4 inhibitor use versus control (42/15,701 v 33/12,591; odds ratio 0.97 (95% confidence interval 0.61 to 1.56); risk difference 2 fewer (19 fewer to 28 more) events per 1000 patients with type 2 diabetes over five years). The observational studies provided effect estimates generally consistent with trial findings, but with very low quality evidence. Pooling of the five trials reporting admission for heart failure provided moderate quality evidence for an increased risk in patients treated with DPP-4 inhibitors versus control (622/18,554 v 552/18,474; 1.13 (1.00 to 1.26); 8 more (0 more to 16 more)). The pooling of adjusted estimates from observational studies similarly suggested (with very low quality evidence) a possible increased risk of admission for heart failure (adjusted odds ratio 1.41, 95% confidence interval 0.95 to 2.09) in patients treated with DPP-4 inhibitors (exclusively sitagliptin) versus no use. The relative effect of DPP-4 inhibitors on the risk of heart failure in patients with type 2 diabetes is uncertain, given the relatively short follow-up and low quality of evidence. Both randomised controlled trials and observational studies, however, suggest that these drugs may increase the risk of hospital admission for heart failure in those patients with existing cardiovascular diseases or multiple risk factors for vascular diseases, compared with no use. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Effects of combination therapy with vildagliptin and valsartan in a mouse model of type 2 diabetes

PubMed Central

2013-01-01

Background Dipeptidyl peptidase-4 (DPP-4) inhibitors modulate incretin hormones and exert anti-diabetic effects in type 2 diabetes mellitus. Treatment with angiotensin II type 1 receptor blockers (ARB) is a proven successful intervention for hypertension with type 2 diabetes. The present study investigated the combined effects of the DPP-4 inhibitor vildagliptin and the ARB valsartan in a mouse model of type 2 diabetes. Methods C57BL/6 J mice fed with high-fat diet (HFD) or db/db mice were treated with placebo, phloridzin (PHZ), vildagliptin alone (ViL), valsartan alone (VaL) or ViL with VaL (ViLVaL) for 8 weeks. Results Glucose metabolism was improved in response to PHZ, ViL and ViLVaL in both HFD and db/db mice. Upon glucose challenge, ViLVaL showed the greatest suppression of blood glucose excursions, with increased insulin secretion, in db/db mice. ViLVaL treatment also showed an improvement of insulin sensitivity in db/db mice. Serum inflammatory cytokines were significantly decreased, and adiponectin was highest, in the ViLVaL group. ViLVaL improved insulin signaling and attenuated stress signaling in liver with amelioration of hepatic steatosis due to activated fatty acid oxidation in db/db mice. Furthermore, immunohistochemical analysis of the pancreas revealed that the combination treatment resulted in an increased expression of insulin and PDX-1, and increased insulin content. Conclusions The combination therapy of ViL and VaL improves both pancreatic beta-cell function and insulin sensitivity, with a reduction of the inflammatory and cell stress milieu in mouse models of T2DM. Our results suggest that this combination therapy exerts additive or even synergistic benefits to treat T2DM. PMID:24188631

Drug use evaluation of diabetes mellitus in hospitalized patients of a tertiary care referral hospital.

PubMed

Khalam, Ameera; Dilip, Chandrasekhar; Shinu, Cholamugath

2012-01-01

Many drugs are available for the treatment of diabetes mellitus and are sometimes prescribed in combination. Irrational use of drugs is increasing expenditure and strain on health budgets. The aim of this study was to determine patient demographic characteristics, analyze prescription patterns of antidiabetic drugs, distribution of complications of diabetes, distribution of co-existing illnesses, distribution of common symptoms of diabetes and distribution of adverse drug reactions. A study was carried out for 11 months in diabetic inpatients in the General Medicine Department. Data of 200 patients were collected and evaluated. The pattern of drug prescription in diabetes shows that insulin (80.5%) was most frequently prescribed followed by biguanides (23%), sulfonylureas (22.5%), thiazolidinediones (11%), dipeptidyl peptidase-IV (DPP-4) inhibitors (9.5%) and meglitinides (5.5%). The percentage of patients on diet control therapy was found to be 3%. Combination therapy was prescribed to 26.5% and monotherapy to 65% of patients; 47.5% of these patients were male and 52.5% were female. The most common co-existing illness was found to be hypertension (53.5%). In addition, 67% of patients had irregular blood sugar monitoring and the remaining 33% had regular (either 4 or 6 hourly) monitoring. It is concluded that the prescribing trend is moving away from monotherapy with insulin and sulfonylureas and towards combination therapies. There is also a significant increase in prescriptions of newer oral antidiabetic drugs, such as DPP-4 inhibitors and insulin analogs. Most inpatients had their blood glucose checked irregularly and haphazardly by ward staff. This study strongly highlights the need for patient education or counseling on use of antidiabetic and concomitant drugs, monitoring of blood glucose and glycosylated hemoglobin (HbA1c) levels, diet control and correction of diabetic complications.

(2R)-4-Oxo-4[3-(Trifluoromethyl)-5,6-diihydro:1,2,4}triazolo[4,3-a}pyrazin-7(8H)-y1]-1-(2,4,5-trifluorophenyl)butan-2-amine: A Potent, Orally Active Dipeptidyl Peptidase IV Inhibitor for the Treatment of Type 2 Diabetes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, D.; Wang, L.; Beconi, M.

2010-11-10

A novel series of {beta}-amino amides incorporating fused heterocycles, i.e., triazolopiperazines, were synthesized and evaluated as inhibitors of dipeptidyl peptidase IV (DPP-IV) for the treatment of type 2 diabetes. (2R)-4-Oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-amine (1) is a potent, orally active DPP-IV inhibitor (IC{sub 50} = 18 nM) with excellent selectivity over other proline-selective peptidases, oral bioavailability in preclinical species, and in vivo efficacy in animal models. MK-0431, the phosphate salt of compound 1, was selected for development as a potential new treatment for type 2 diabetes.

Sitagliptin but not alpha glucosidase inhibitor reduced the serum soluble CD163, a marker for activated macrophage, in individuals with type 2 diabetes mellitus.

PubMed

Hattori, Akiko; Takemoto, Minoru; Tokuyama, Hirotake; Koshizaka, Masaya; Yokote, Koutaro

2017-04-01

Dipeptidyl peptidase-4 inhibitor (DPP-4i) is commonly used worldwide for the treatment of type 2 diabetes mellitus. In addition to its hypoglycemic activity, DPP-4i might have anti-inflammatory effects. In this study we examined the effects of DPP-4i on the serum levels of soluble CD163 (sCD163), a marker for activated macrophages, in individuals with type 2 diabetes mellitus. We compared these anti-inflammatory effects with those of α glucosidase inhibitor (αGI). Japanese patients with type 2 diabetes mellitus who were stably maintained on ≤2mg/day glimepiride alone were recruited and randomly assigned to receive additional sitagliptin (n=37) or αGI (n=37). Levels of sCD163 were measured before the addition and after a 24-week treatment period. Addition of sitagliptin significantly reduced the serum sCD163 (632 vs. 575ng/mL, p<0.05), while αGI did not display this effect (624 vs. 607ng/mL). The changes in levels of sCD163 were not related to changes in either HbA1c or body mass index (BMI). Our results suggested that DPP-4i might exert anti-inflammatory effects in individuals with type 2 diabetes mellitus, which are independent of its effects on glycemia and BMI. Copyright © 2017 Elsevier B.V. All rights reserved.

Changes in Gene Expression Profiles in Adult Rat Brain Structures after Neonatal Action of Dipeptidyl Peptidase-IV Inhibitors.

PubMed

Zubkov, Eugene A; Zorkina, Yana A; Orshanskaya, Elena V; Khlebnikova, Nadezhda N; Krupina, Natalia A; Chekhonin, Vladimir P

2017-01-01

Previous studies have shown the development of emotional and motivational disorders, such as anxiety-depression-like disorders with increased aggression in adolescent and adult Wistar rats, occurs after neonatal exposure to the dipeptidyl peptidase-IV (DPP-IV, EC 3.4.14.5) inhibitors diprotin A and sitagliptin (postnatal days 5-18). In this study, using real-time PCR, we evaluated changes in the gene expression of serine protease DPP-IV and prolyl endopeptidase (PREP, EC 3.4.21.26; dpp4 and prep genes), monoamine oxidase А (maoA) and B (maoB), and serotonin transporter (SERT; sert) in the brain structures from 3-month-old rats after postnatal action of DPP-IV inhibitors diprotin A and sitagliptin. Dpp4, sert, and maoB gene expression increased and maoA gene expression changed with a tendency to increase in the striatum of rats with neonatal sitagliptin action. The increase of maoA gene expression was also shown in the amygdala. An increase in prep gene expression was found in the striatum of rats with the neonatal action of diprotin A, and a decrease in maoB gene expression was observed in the amygdala. We detected a significant downward trend in sert gene expression in the frontal cortex and amygdala, as well as a tendency to increase in maoA gene expression in the hypothalamus. These findings suggest that changes in the expression of the abovementioned genes are associated with the development of anxiety and depression, with increased aggression caused by the neonatal action of diprotin A and sitagliptin. © 2018 S. Karger AG, Basel.

Type 2 diabetes mellitus and heart failure: a position statement from the Heart Failure Association of the European Society of Cardiology.

PubMed

Seferović, Petar M; Petrie, Mark C; Filippatos, Gerasimos S; Anker, Stefan D; Rosano, Giuseppe; Bauersachs, Johann; Paulus, Walter J; Komajda, Michel; Cosentino, Francesco; de Boer, Rudolf A; Farmakis, Dimitrios; Doehner, Wolfram; Lambrinou, Ekaterini; Lopatin, Yuri; Piepoli, Massimo F; Theodorakis, Michael J; Wiggers, Henrik; Lekakis, John; Mebazaa, Alexandre; Mamas, Mamas A; Tschöpe, Carsten; Hoes, Arno W; Seferović, Jelena P; Logue, Jennifer; McDonagh, Theresa; Riley, Jillian P; Milinković, Ivan; Polovina, Marija; van Veldhuisen, Dirk J; Lainscak, Mitja; Maggioni, Aldo P; Ruschitzka, Frank; McMurray, John J V

2018-05-01

The coexistence of type 2 diabetes mellitus (T2DM) and heart failure (HF), either with reduced (HFrEF) or preserved ejection fraction (HFpEF), is frequent (30-40% of patients) and associated with a higher risk of HF hospitalization, all-cause and cardiovascular (CV) mortality. The most important causes of HF in T2DM are coronary artery disease, arterial hypertension and a direct detrimental effect of T2DM on the myocardium. T2DM is often unrecognized in HF patients, and vice versa, which emphasizes the importance of an active search for both disorders in the clinical practice. There are no specific limitations to HF treatment in T2DM. Subanalyses of trials addressing HF treatment in the general population have shown that all HF therapies are similarly effective regardless of T2DM. Concerning T2DM treatment in HF patients, most guidelines currently recommend metformin as the first-line choice. Sulphonylureas and insulin have been the traditional second- and third-line therapies although their safety in HF is equivocal. Neither glucagon-like preptide-1 (GLP-1) receptor agonists, nor dipeptidyl peptidase-4 (DPP4) inhibitors reduce the risk for HF hospitalization. Indeed, a DPP4 inhibitor, saxagliptin, has been associated with a higher risk of HF hospitalization. Thiazolidinediones (pioglitazone and rosiglitazone) are contraindicated in patients with (or at risk of) HF. In recent trials, sodium-glucose co-transporter-2 (SGLT2) inhibitors, empagliflozin and canagliflozin, have both shown a significant reduction in HF hospitalization in patients with established CV disease or at risk of CV disease. Several ongoing trials should provide an insight into the effectiveness of SGLT2 inhibitors in patients with HFrEF and HFpEF in the absence of T2DM. © 2018 The Authors. European Journal of Heart Failure © 2018 European Society of Cardiology.

DPP-4 Inhibitor Treatment in Chinese Type 2 Diabetes Patients: A Meta-Analysis.

PubMed

Cai, Xiaoling; Gao, Xueying; Yang, Wenjia; Chen, Yifei; Zhou, Lingli; Zhang, Simin; Han, Xueyao; Ji, Linong

2016-12-01

The aim of this meta-analysis was to assess the comprehensive clinical efficacy of dipeptidyl peptidase-IV (DPP-4) inhibitors in Chinese type 2 diabetes patients and to evaluate whether there is a different response to treatment with different kinds of DPP-4 inhibitors in those patients. Databases were systematically searched, and qualifying clinical studies of Chinese type 2 diabetes patients were included. A total of 30 studies were included. Treatment with saxagliptin resulted in a significantly greater change from baseline in HbA 1c levels (weighted mean difference [WMD], -1.28%; 95% CI, -1.37% to -1.19%); treatment with sitagliptin led to a significantly greater change from baseline (WMD, -1.17%; 95% CI, -1.46% to -0.89%); treatment with vildagliptin was associated with a significantly greater change in HbA 1c levels (WMD, -0.77%; 95% CI, -0.88% to -0.65%); treatment with linagliptin led to a significantly greater change (WMD, -0.84%; 95% CI, -0.92% to -0.75%); and treatment with alogliptin also led to a significantly greater change (WMD, -0.91%; 95% CI, -1.48% to -0.33%). In terms of body weight, treatment with saxagliptin was associated with no significant decreases in Chinese type 2 diabetes mellitus (T2DM) patients (WMD, -0.17 kg, 95% CI, -4.26 to 3.92 kg). Treatment with sitagliptin and linagliptin was also associated with no significant changes in body weight (WMD, 0.16 and 0.11 kg, respectively, P > 0.05). In Chinese type 2 diabetes patients, the efficacy of glucose control in all five kinds of DPP-4 inhibitor treatments was well confirmed, and no significant change in body weight was found.

Microfluidic Assembly of a Multifunctional Tailorable Composite System Designed for Site Specific Combined Oral Delivery of Peptide Drugs.

PubMed

Araújo, Francisca; Shrestha, Neha; Shahbazi, Mohammad-Ali; Liu, Dongfei; Herranz-Blanco, Bárbara; Mäkilä, Ermei M; Salonen, Jarno J; Hirvonen, Jouni T; Granja, Pedro L; Sarmento, Bruno; Santos, Hélder A

2015-08-25

Multifunctional tailorable composite systems, specifically designed for oral dual-delivery of a peptide (glucagon-like peptide-1) and an enzymatic inhibitor (dipeptidyl peptidase 4 (DPP4)), were assembled through the microfluidics technique. Both drugs were coloaded into these systems for a synergistic therapeutic effect. The systems were composed of chitosan and cell-penetrating peptide modified poly(lactide-co-glycolide) and porous silicon nanoparticles as nanomatrices, further encapsulated in an enteric hydroxypropylmethylcellulose acetylsuccinate polymer. The developed multifunctional systems were pH-sensitive, inherited by the enteric polymer, enabling the release of the nanoparticles only in the simulated intestinal conditions. Moreover, the encapsulation into this polymer prevented the degradation of the nanoparticles' modifications. These nanoparticles showed strong and higher interactions with the intestinal cells in comparison with the nonmodified ones. The presence of DPP4 inhibitor enhanced the peptide permeability across intestinal cell monolayers. Overall, this is a promising platform for simultaneously delivering two drugs from a single formulation. Through this approach peptides are expected to increase their bioavailability and efficiency in vivo both by their specific release at the intestinal level and also by the reduced enzymatic activity. The use of this platform, specifically in combination of the two antidiabetic drugs, has clinical potential for the therapy of type 2 diabetes mellitus.

Molecular and clinical roles of incretin-based drugs in patients with heart failure.

PubMed

Orabi, Bassant; Kaddoura, Rasha; Omar, Amr S; Carr, Cornelia; Alkhulaifi, Abdulaziz

2018-05-01

Glucagon-like peptide-1 (GLP-1) agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors produce some beneficial and deleterious effects in diabetic patients not mediated by their glycemic lowering effects, and there is a need for better understanding of the molecular basis of these effects. They possess antioxidant and anti-inflammatory effects with some direct vasodilatory action (animal and human trial data) that may indirectly influence heart failure (HF). Unlike GLP-1R agonists, signaling for HF adverse effects was observed with two DPP-4 inhibitors, saxagliptin and alogliptin. Accordingly, these drugs should be used with caution in heart failure patients.

Inhibition of dipeptidyl peptidase 4 regulates microvascular endothelial growth induced by inflammatory cytokines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takasawa, Wataru; Ohnuma, Kei; Hatano, Ryo

2010-10-08

Research highlights: {yields} TNF-{alpha} or IL-1{beta} induces EC proliferation with reduction of CD26 expression. {yields} CD26 siRNA or DPP-4 inhibition enhances TNF-{alpha} or IL-1{beta}-induced EC proliferation. {yields} Loss of CD26/DPP-4 enhances aortic sprouting induced by TNF-{alpha} or IL-1{beta}. {yields} Capillary formation induced by TNF-{alpha} or IL-1{beta} is enahced in the CD26{sup -/-} mice. -- Abstract: CD26/DPP-4 is abundantly expressed on capillary of inflamed lesion as well as effector T cells. Recently, CD26/dipeptidyl peptidase 4 (DPP-4) inhibition has been used as a novel oral therapeutic approach for patients with type 2 diabetes. While accumulating data indicate that vascular inflammation is amore » key feature of both micro- and macro-vascular complications in diabetes, the direct role of CD26/DPP-4 in endothelial biology is to be elucidated. We herein showed that proinflammatory cytokines such as tumor necrosis factor or interleukin-1 reduce expression of CD26 on microvascular endothelial cells, and that genetical or pharmacological inhibition of CD26/DPP-4 enhances endothelial growth both in vitro and in vivo. With DPP-4 inhibitors being used widely in the treatment of type 2 diabetes, our data strongly suggest that DPP-4 inhibition plays a pivotal role in endothelial growth and may have a potential role in the recovery of local circulation following diabetic vascular complications.« less

Reduction of serum FABP4 level by sitagliptin, a DPP-4 inhibitor, in patients with type 2 diabetes mellitus.

PubMed

Furuhashi, Masato; Hiramitsu, Shinya; Mita, Tomohiro; Fuseya, Takahiro; Ishimura, Shutaro; Omori, Akina; Matsumoto, Megumi; Watanabe, Yuki; Hoshina, Kyoko; Tanaka, Marenao; Moniwa, Norihito; Yoshida, Hideaki; Ishii, Junnichi; Miura, Tetsuji

2015-12-01

Fatty acid binding protein 4 (FABP4), also known as adipocyte FABP or aP2, is secreted from adipocytes in association with lipolysis as a novel adipokine, and elevated serum FABP4 level is associated with obesity, insulin resistance, and atherosclerosis. However, little is known about the modulation of serum FABP4 level by therapeutic drugs. Sitagliptin (50 mg/day), a dipeptidyl peptidase 4 (DPP-4) inhibitor that increases glucagon-like peptide 1 (GLP-1), was administered to patients with type 2 diabetes (n = 24) for 12 weeks. Treatment with sitagliptin decreased serum FABP4 concentration by 19.7% (17.8 ± 1.8 vs. 14.3 ± 1.5 ng/ml, P < 0.001) and hemoglobin A1c without significant changes in adiposity or lipid variables. In 3T3-L1 adipocytes, sitagliptin or exendin-4, a GLP-1 receptor agonist, had no effect on short-term (2 h) secretion of FABP4. However, gene expression and long-term (24 h) secretion of FABP4 were significantly reduced by sitagliptin, which was not mimicked by exendin-4. Treatment with recombinant DPP-4 increased gene expression and long-term secretion of FABP4, and the effects were cancelled by sitagliptin. Furthermore, knockdown of DPP-4 in 3T3-L1 adipocytes decreased gene expression and long-term secretion of FABP4. In conclusion, sitagliptin decreases serum FABP4 level, at least in part, via reduction in the expression and consecutive secretion of FABP4 in adipocytes by direct inhibition of DPP-4. Copyright © 2015 by the American Society for Biochemistry and Molecular Biology, Inc.

Long-term efficacy and safety of vildagliptin add-on therapy in type 2 diabetes mellitus with insulin treatment.

PubMed

Kanazawa, Ippei; Tanaka, Ken-Ichiro; Notsu, Masakazu; Tanaka, Sayuri; Kiyohara, Nobuaki; Koike, Sayo; Yamane, Yuko; Tada, Yuko; Sasaki, Motofumi; Yamauchi, Mika; Sugimoto, Toshitsugu

2017-01-01

The use of dipeptidyl peptidase (DPP)-4 inhibitors in patients with type 2 diabetes treated with insulin may be beneficial. However, the long-term efficacy and safety of vildagliptin add-on therapy in these patients remains unclear. A total of 73 patients with type 2 diabetes treated with insulin were randomly assigned to receive either add-on therapy of vildagliptin (n=37) or conventional therapy without DPP-4 inhibitors (n=36) for glucose control. Hemoglobin A1c (HbA1c) levels, dose and number of insulin injections, number of hypoglycemia episodes, and liver and renal function were monitored for 2years. The baseline characteristics of subjects, including age, dose of insulin injections, or HbA1c levels, did not differ between the two groups. In the vildagliptin group, HbA1c levels significantly decreased and the significance of HbA1c reduction was maintained for 24months (from 8.0±1.2% to 7.4±1.0%, p<0.05, at the end of observational period). In addition, the dose and number of insulin injections significantly reduced (-5.6units, p<0.01, and -0.9 times, p<0.001). However, these parameters were unchanged in the control group. The number of patients who experienced three or more episodes of hypoglycemia per year was significantly lower in the vildagliptin group (n=4) than in the control group (n=11) (odds ratio, 0.28; 95% confidence interval, 0.08-0.97; p<0.05). Vildagliptin as an add-on to insulin treatment for 24months was well tolerated and led to sustained reductions in HbA1c, the dose and number of insulin injections, and the risk of hypoglycemia. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Synthesis, QSAR, and Molecular Dynamics Simulation of Amidino-substituted Benzimidazoles as Dipeptidyl Peptidase III Inhibitors.

PubMed

Rastija, Vesna; Agić, Dejan; Tomiš, Sanja; Nikolič, Sonja; Hranjec, Marijana; Grace, Karminski-Zamola; Abramić, Marija

2015-01-01

A molecular modeling study is performed on series of benzimidazol-based inhibitors of human dipeptidyl peptidase III (DPP III). An eight novel compounds were synthesized in excellent yields using green chemistry approach. This study is aimed to elucidate the structural features of benzimidazole derivatives required for antagonism of human DPP III activity using Quantitative Structure-Activity Relationship (QSAR) analysis, and to understand the mechanism of one of the most potent inhibitor binding into the active site of this enzyme, by molecular dynamics (MD) simulations. The best model obtained includes S3K and RDF045m descriptors which have explained 89.4 % of inhibitory activity. Depicted moiety for strong inhibition activity matches to the structure of most potent compound. MD simulation has revealed importance of imidazolinyl and phenyl groups in the mechanism of binding into the active site of human DPP III.

Medicinal Chemistry and Applications of Incretins and DPP-4 Inhibitors in the Treatment of Type 2 Diabetes Mellitus

PubMed Central

Lotfy, Mohamed; Singh, Jaipaul; Kalász, Huba; Tekes, Kornelia; Adeghate, Ernest

2011-01-01

Diabetes mellitus (DM) is a major metabolic disorder currently affecting over 200 million people worldwide. Approximately 90% of all diabetic patients suffer from Type 2 diabetes mellitus (T2DM). The world's economy coughs out billions of dollars annually to diagnose, treat and manage patients with diabetes. It has been shown that the naturally occurring gut hormones incretins, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) can preserve the morphology and function of pancreatic beta cell. In addition, GIP and GLP-1 act on insulin receptors to facilitate insulin-receptor binding, resulting in optimal glucose metabolism. This review examines the medicinal chemistry and roles of incretins, specifically, GLP-1 and drugs which can mimic its actions and prevent its enzymatic degradation. The review discussed GLP-1 agonists such as exenatide, liraglutide, taspoglutide and albiglutide. The paper also identified and reviewed a number of inhibitors, which can block dipeptidyl peptidase 4 (DPP-4), the enzyme responsible for the rapid degradation of GLP-1. These DPP-4 inhibitors include sitagliptin, saxagliptin, vildagliptin and many others which are still in the experimental phase. PMID:21966329

Involvement of DPP-IV catalytic residues in enzyme–saxagliptin complex formation

PubMed Central

Metzler, William J.; Yanchunas, Joseph; Weigelt, Carolyn; Kish, Kevin; Klei, Herbert E.; Xie, Dianlin; Zhang, Yaqun; Corbett, Martin; Tamura, James K.; He, Bin; Hamann, Lawrence G.; Kirby, Mark S.; Marcinkeviciene, Jovita

2008-01-01

The inhibition of DPP-IV by saxagliptin has been proposed to occur through formation of a covalent but reversible complex. To evaluate further the mechanism of inhibition, we determined the X-ray crystal structure of the DPP-IV:saxagliptin complex. This structure reveals covalent attachment between S630 and the inhibitor nitrile carbon (C–O distance <1.3 Å). To investigate whether this serine addition is assisted by the catalytic His-Asp dyad, we generated two mutants of DPP-IV, S630A and H740Q, and assayed them for ability to bind inhibitor. DPP-IVH740Q bound saxagliptin with an ∼1000-fold reduction in affinity relative to DPP-IVWT, while DPP-IVS630A showed no evidence for binding inhibitor. An analog of saxagliptin lacking the nitrile group showed unchanged binding properties to the both mutant proteins, highlighting the essential role S630 and H740 play in covalent bond formation between S630 and saxagliptin. Further supporting mechanism-based inhibition by saxagliptin, NMR spectra of enzyme–saxagliptin complexes revealed the presence of three downfield resonances with low fractionation factors characteristic of short and strong hydrogen bonds (SSHB). Comparison of the NMR spectra of various wild-type and mutant DPP-IV:ligand complexes enabled assignment of a resonance at ∼14 ppm to H740. Two additional DPP-IV mutants, Y547F and Y547Q, generated to probe potential stabilization of the enzyme–inhibitor complex by this residue, did not show any differences in inhibitor binding either by ITC or NMR. Together with the previously published enzymatic data, the structural and binding data presented here strongly support a histidine-assisted covalent bond formation between S630 hydroxyl oxygen and the nitrile group of saxagliptin. PMID:18227430

Involvement of DPP-IV Catalytic Residues in Enzyme-Saxagliptin Complex Formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metzler,W.; Yanchunas, J.; Weigelt, C.

The inhibition of DPP-IV by saxagliptin has been proposed to occur through formation of a covalent but reversible complex. To evaluate further the mechanism of inhibition, we determined the X-ray crystal structure of the DPP-IV:saxagliptin complex. This structure reveals covalent attachment between S630 and the inhibitor nitrile carbon (C-O distance <1.3 Angstroms). To investigate whether this serine addition is assisted by the catalytic His-Asp dyad, we generated two mutants of DPP-IV, S630A and H740Q, and assayed them for ability to bind inhibitor. DPP-IVH740Q bound saxagliptin with an {approx}1000-fold reduction in affinity relative to DPP-IVWT, while DPP-IVS630A showed no evidence formore » binding inhibitor. An analog of saxagliptin lacking the nitrile group showed unchanged binding properties to the both mutant proteins, highlighting the essential role S630 and H740 play in covalent bond formation between S630 and saxagliptin. Further supporting mechanism-based inhibition by saxagliptin, NMR spectra of enzyme-saxagliptin complexes revealed the presence of three downfield resonances with low fractionation factors characteristic of short and strong hydrogen bonds (SSHB). Comparison of the NMR spectra of various wild-type and mutant DPP-IV:ligand complexes enabled assignment of a resonance at {approx}14 ppm to H740. Two additional DPP-IV mutants, Y547F and Y547Q, generated to probe potential stabilization of the enzyme-inhibitor complex by this residue, did not show any differences in inhibitor binding either by ITC or NMR. Together with the previously published enzymatic data, the structural and binding data presented here strongly support a histidine-assisted covalent bond formation between S630 hydroxyl oxygen and the nitrile group of saxagliptin.« less

In silico approaches to predict the potential of milk protein-derived peptides as dipeptidyl peptidase IV (DPP-IV) inhibitors.

PubMed

Nongonierma, Alice B; Mooney, Catherine; Shields, Denis C; FitzGerald, Richard J

2014-07-01

Molecular docking of a library of all 8000 possible tripeptides to the active site of DPP-IV was used to determine their binding potential. A number of tripeptides were selected for experimental testing, however, there was no direct correlation between the Vina score and their in vitro DPP-IV inhibitory properties. While Trp-Trp-Trp, the peptide with the best docking score, was a moderate DPP-IV inhibitor (IC50 216μM), Lineweaver and Burk analysis revealed its action to be non-competitive. This suggested that it may not bind to the active site of DPP-IV as assumed in the docking prediction. Furthermore, there was no significant link between DPP-IV inhibition and the physicochemical properties of the peptides (molecular mass, hydrophobicity, hydrophobic moment (μH), isoelectric point (pI) and charge). LIGPLOTs indicated that competitive inhibitory peptides were predicted to have both hydrophobic and hydrogen bond interactions with the active site of DPP-IV. DPP-IV inhibitory peptides generally had a hydrophobic or aromatic amino acid at the N-terminus, preferentially a Trp for non-competitive inhibitors and a broader range of residues for competitive inhibitors (Ile, Leu, Val, Phe, Trp or Tyr). Two of the potent DPP-IV inhibitors, Ile-Pro-Ile and Trp-Pro (IC50 values of 3.5 and 44.2μM, respectively), were predicted to be gastrointestinally/intestinally stable. This work highlights the needs to test the assumptions (i.e. competitive binding) of any integrated strategy of computational and experimental screening, in optimizing screening. Future strategies targeting allosteric mechanisms may need to rely more on structure-activity relationship modeling, rather than on docking, in computationally selecting peptides for screening. Copyright © 2014 Elsevier Inc. All rights reserved.

The effect of dipeptidyl peptidase-IV inhibition on bone in a mouse model of type 2 diabetes

PubMed Central

Gallagher, Emily Jane; Sun, Hui; Kornhauser, Caroline; Tobin-Hess, Aviva; Epstein, Sol; Yakar, Shoshana; LeRoith, Derek

2017-01-01

Background Individuals with type 2 diabetes (T2D) are at greater risk of bone fractures than those without diabetes. Certain oral diabetic medications may further increase the risk of fracture. Dipeptidyl peptidase-IV (DPP-IV) inhibitors are incretin-based therapies that are being increasingly used for the management of T2D. It has been hypothesized that these agents may reduce fracture risk in those with T2D. In this study, we used a mouse model of T2D to examine the effects of the DPP-IV inhibitor, MK-0626, on bone. Methods Male wild type (WT) and diabetic muscle-lysine-arginine (MKR) mice were treated with MK-0626, pioglitazone, alendronate or vehicle. The effects of treatment with MK-0626 on bone microarchitecture and turnover were compared with treatment with pioglitazone, alendronate and vehicle. Osteoblast differentiation was determined by alkaline phosphatase staining of bone marrow cells from WT and MKR mice after treatment with pioglitazone, MK-0626 or phosphate buffered saline. Results We found that MK-0626 had neutral effects on cortical and trabecular bone in diabetic mice. Pioglitazone had detrimental effects on the trabecular bone of WT but not of diabetic mice. Alendronate caused improvements in cortical and trabecular bone architecture in diabetic and WT mice. MK-0626 did not alter osteoblast differentiation, but pioglitazone impaired osteoblast differentiation in vitro. Conclusions Overall, the DPP-IV inhibitor, MK-0626, had no adverse effects on bone in an animal model of T2D or directly on osteoblasts in culture. These findings are reassuring as DPP-IV inhibitors are being widely used to treat patients with T2D who are already at an increased risk of fractures. PMID:24023014

Comparison of the susceptibility of porcine and human dipeptidyl-peptidase IV to inhibition by protein-derived peptides.

PubMed

Lacroix, Isabelle M E; Li-Chan, Eunice C Y

2015-07-01

The enzyme dipeptidyl-peptidase IV (DPP-IV) is recognized to be a promising target for the management of type 2 diabetes. Over the last decade, numerous synthetic molecules and more recently, peptides from dietary proteins, have been reported to be able to inhibit DPP-IV activity. Most studies that have investigated the in vitro effect of these inhibitors have used porcine or human DPP-IV. Although structurally alike, it is unclear whether these two species display similar inhibition patterns. Therefore, the objective of this study was to compare the effects of protein-derived peptides on the activity of porcine and recombinant human DPP-IV. The two species showed different inhibition susceptibility to 43 of the 62 peptide sequences investigated. While 37 protein-derived peptides were more effective at inhibiting the porcine DPP-IV, only six caused a stronger inhibition of the activity of the human enzyme. Although the peptides WR, IPIQY and WCKDDQNPHS were found to be among the most potent inhibitors of both species, the inhibitory effect was greater on the porcine enzyme than on human DPP-IV (αKi or Ki=11.5, 13.4, 13.3 μM and 31.4, 28.2, 75.0 μM for porcine and human DPP-IV, respectively). Investigation into the mode of action of the most effective inhibitory peptides revealed that both species were inhibited in a similar manner by short fragments (≤5 amino acid residues), but that some of the longer peptides acted differently on the enzymes. This study shows that porcine DPP-IV is generally inhibited with greater potency by protein-derived peptides than is the human enzyme. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of Inhibiting Dipeptidyl Peptidase-4 (DPP4) in Cows with Subclinical Ketosis

PubMed Central

Schulz, Kirsten; Frahm, Jana; Kersten, Susanne; Meyer, Ulrich; Rehage, Jürgen; Piechotta, Marion; Meyerholz, Maria; Breves, Gerhard; Reiche, Dania; Sauerwein, Helga; Dänicke, Sven

2015-01-01

The inhibition of dipeptidyl peptidase-4 (DPP4) via specific inhibitors is known to result in improved glucose tolerance and insulin sensitivity and decreased accumulation of hepatic fat in type II diabetic human patients. The metabolic situation of dairy cows can easily be compared to the status of human diabetes and non-alcoholic fatty liver. For both, insulin sensitivity is reduced, while hepatic fat accumulation increases, characterized by high levels of non-esterified fatty acids (NEFA) and ketone bodies.Therefore, in the present study, a DPP4 inhibitor was employed (BI 14332) for the first time in cows. In a first investigation BI 14332 treatment (intravenous injection at dosages of up to 3 mg/kg body weight) was well tolerated in healthy lactating pluriparous cows (n = 6) with a significant inhibition of DPP4 in plasma and liver. Further testing included primi- and pluriparous lactating cows suffering from subclinical ketosis (β-hydroxybutyrate concentrations in serum > 1.2 mM; n = 12). The intension was to offer effects of DPP4 inhibition during comprehensive lipomobilisation and hepatosteatosis. The cows of subclinical ketosis were evenly allocated to either the treatment group (daily injections, 0.3 mg BI 14332/kg body weight, 7 days) or the control group. Under condition of subclinical ketosis, the impact of DPP4 inhibition via BI 14332 was less, as in particular β-hydroxybutyrate and the hepatic lipid content remained unaffected, but NEFA and triglyceride concentrations were decreased after treatment. Owing to lower NEFA, the revised quantitative insulin sensitivity check index (surrogate marker for insulin sensitivity) increased. Therefore, a positive influence on energy metabolism might be quite possible. Minor impacts on immune-modulating variables were limited to the lymphocyte CD4+/CD8+ ratio for which a trend to decreased values in treated versus control animals was noted. In sum, the DPP4 inhibition in cows did not affect glycaemic control like it is shown in humans, but was able to impact hyperlipemia, as NEFA and TG decreased. PMID:26291537

The Dipeptidyl Peptidase-4 Inhibitor Teneligliptin Attenuates Hepatic Lipogenesis via AMPK Activation in Non-Alcoholic Fatty Liver Disease Model Mice.

PubMed

Ideta, Takayasu; Shirakami, Yohei; Miyazaki, Tsuneyuki; Kochi, Takahiro; Sakai, Hiroyasu; Moriwaki, Hisataka; Shimizu, Masahito

2015-12-08

Non-alcoholic fatty liver disease (NAFLD), which is strongly associated with metabolic syndrome, is increasingly a major cause of hepatic disorder. Dipeptidyl peptidase (DPP)-4 inhibitors, anti-diabetic agents, are expected to be effective for the treatment of NAFLD. In the present study, we established a novel NAFLD model mouse using monosodium glutamate (MSG) and a high-fat diet (HFD) and investigated the effects of a DPP-4 inhibitor, teneligliptin, on the progression of NAFLD. Male MSG/HFD-treated mice were divided into two groups, one of which received teneligliptin in drinking water. Administration of MSG and HFD caused mice to develop severe fatty changes in the liver, but teneligliptin treatment improved hepatic steatosis and inflammation, as evaluated by the NAFLD activity score. Serum alanine aminotransferase and intrahepatic triglyceride levels were significantly decreased in teneligliptin-treated mice (p < 0.05). Hepatic mRNA levels of the genes involved in de novo lipogenesis were significantly downregulated by teneligliptin (p < 0.05). Moreover, teneligliptin increased hepatic expression levels of phosphorylated AMP-activated protein kinase (AMPK) protein. These findings suggest that teneligliptin attenuates lipogenesis in the liver by activating AMPK and downregulating the expression of genes involved in lipogenesis. DPP-4 inhibitors may be effective for the treatment of NAFLD and may be able to prevent its progression to non-alcoholic steatohepatitis.

Bioactive compounds from culinary herbs inhibit a molecular target for type 2 diabetes management, dipeptidyl peptidase IV.

PubMed

Bower, Allyson M; Real Hernandez, Luis M; Berhow, Mark A; de Mejia, Elvira Gonzalez

2014-07-02

Greek oregano (Origanum vulgare), marjoram (Origanum majorana), rosemary (Rosmarinus officinalis), and Mexican oregano (Lippia graveolens) are concentrated sources of bioactive compounds. The aims were to characterize and examine extracts from greenhouse-grown or commercially purchased herbs for their ability to inhibit dipeptidyl peptidase IV (DPP-IV) and protein tyrosine phosphatase 1B (PTP1B), enzymes that play a role in insulin secretion and insulin signaling, respectively. Greenhouse herbs contained more polyphenols (302.7-430.1 μg of gallic acid equivalents/mg of dry weight of extract (DWE)) and flavonoids (370.1-661.4 μg of rutin equivalents/mg of DWE) compared to the equivalent commercial herbs. Greenhouse rosemary, Mexican oregano, and marjoram extracts were the best inhibitors of DPP-IV (IC₅₀=16, 29, and 59 μM, respectively). Commercial rosemary, Mexican oregano, and marjoram were the best inhibitors of PTP1B (32.4-40.9% at 500 μM). The phytochemicals eriodictyol, naringenin, hispidulin, cirsimaritin, and carnosol were identified by LC-ESI-MS as being present in greenhouse-grown Mexican oregano and rosemary. Computational modeling indicated that hispidulin, carnosol, and eriodictyol would have the best binding affinities for DPP-IV. Biochemically, the best inhibitors of DPP-IV were cirsimaritin (IC₅₀=0.43±0.07 μM), hispidulin (IC₅₀=0.49±0.06 μM), and naringenin (IC₅₀=2.5±0.29 μM). Overall, herbs contain several flavonoids that inhibit DPP-IV and should be investigated further regarding their potential in diabetes management.

Concordance with prescribing information dosage recommendations for dipeptidyl-peptidase-4 inhibitors among type 2 diabetes mellitus patients with moderate to severe chronic kidney disease.

PubMed

Huang, Huan; Shetty, Sharash; Bauer, Elise; Lang, Kathleen

2018-06-01

To estimate the proportion of patients with moderate to severe chronic kidney disease (CKD) whose initial dipeptidyl-peptidase-4 inhibitor (DPP4-i) dosage was concordant with prescribing information (label) recommendations in the United States. Adult patients with type 2 diabetes mellitus (T2DM) who initiated a DPP4-i (linagliptin, sitagliptin, saxagliptin) between 1 January 2011 and 30 June 2014 were identified using electronic medical records and administrative claims, with index date being the date of first observed DPP4-i treatment. Patients were required to have chronic kidney disease (CKD) stage 3b, 4 or 5 (estimated Glomerular Filtration Rate [eGFR] value <45 ml/min/1.73 m 2 ) during the 12 month pre-index period. Patients were classified as concordant or not concordant based on whether the first prescribed dose was consistent with label recommendations. Demographics, clinical characteristics, resource use and costs during pre-index were evaluated by DPP4-i concordance status. Of the 492 patients (323 sitagliptin, 57 saxagliptin, 112 linagliptin), 36.2% were prescribed doses that were not concordant with label recommendations (44.9% for sitagliptin, 57.9% for saxagliptin and 0% for linagliptin [which does not require dosage adjustment]). Concordant patients were slightly older (mean age 71 years vs. 68, p = .01) but had similar gender distribution (55% vs. 60% female, p = .31) compared to those who were not concordant. They had lower general health status (Charlson Comorbidity Score 2.6 vs. 2.2, p = .03), and had similar pre-index all-cause total costs ($25,245 vs. $21,972, p = .68) and lower pre-index T2DM-related costs ($1618 vs. $1922, p = .05). More than a third of DPP4-i patients with CKD stage 3b or higher were prescribed doses not concordant with DPP4-i label dosage recommendations.

A Common Susceptibility Gene for Type 2 Diabetes Is Associated with Drug Response to a DPP-4 Inhibitor: Pharmacogenomic Cohort in Okinawa Japan.

PubMed

Osada, Uru Nezu; Sunagawa, Hiroshi; Terauchi, Yasuo; Ueda, Shinichiro

2016-01-01

We investigated the association between common type 2 susceptibility variants of CDK5 regulatory subunit associated protein 1-like 1(CDKAL1) and therapeutic responses to anti-diabetic agents among patients with type 2 diabetes. Two SNPs (rs7754840: C>G, rs7756992: A>G) were genotyped via the Taqman PCR method. A total of 798 type 2 diabetic patients were included. HbA1c reduction after use of DPP-4 inhibitors for 3 months was significantly greater in patients with a risk allele for type 2 diabetes (GG -0.4%, CG -0.5%, CC -0.8%, p = 0.02 for rs7754840 and AA -0.4%, AG -0.5%, GG -0.8%, p = 0.01 for rs7756992). Linear regression analysis showed that per allele reductions of hemoglobin A1c (HbA1c) after 3 months were -0.10% for rs7754840 (p = 0.02) and -0.13% for rs7756992 (p = 0.0008) after adjusting for clinically influential covariates such as age, sex, BMI, duration of diabetes, baseline HbA1c and concomitant anti-diabetic agents. The results suggested that common variants of CDKAL1 are associated with therapeutic response to DPP-4 inhibitors.

Changes in Adenosine Deaminase Activity in Patients with Type 2 Diabetes Mellitus and Effect of DPP-4 Inhibitor Treatment on ADA Activity.

PubMed

Lee, Jae-Geun; Kang, Dong Gu; Yu, Jung Re; Kim, Youngree; Kim, Jinsoek; Koh, Gwanpyo; Lee, Daeho

2011-04-01

Dipeptidyl peptidase 4 (DPP-4, also known as CD26) binds with adenosine deaminase (ADA) to activate T lymphocytes. Here, we investigated whether ADA activity is specifically affected by treatment with DPP-4 inhibitor (DPP4I) compared with other anti-diabetic agents. Fasting ADA activity, in addition to various metabolic and biochemical parameters, were measured in 262 type 2 diabetes mellitus (T2DM) patients taking various anti-diabetic agents and in 46 non-diabetic control subjects. ADA activity was increased in T2DM patients compared with that in non-diabetic control subjects (mean±standard error, 23.1±0.6 U/L vs. 18.6±0.8 U/L; P<0.05). ADA activity was correlated with fasting plasma glucose (r=0.258, P<0.05), HbA1c (r=0.208, P<0.05), aspartate aminotransferase (r=0.325, P<0.05), and alanine aminotransferase (r=0.248, P<0.05). Compared with the well-controlled T2DM patients (HbA1c<7%), the poorly controlled group (HbA1c>9%) showed significantly increased ADA activity (21.1±0.8 U/L vs. 25.4±1.6 U/L; P<0.05). The effect of DPP4I on ADA activity in T2DM patients did not differ from those of other oral anti-diabetic agents or insulin. T2DM patients on metformin monotherapy showed a lower ADA activity (20.9±1.0 U/L vs. 28.1±2.8 U/L; P<0.05) compared with that of those on sulfonylurea monotherapy. Our results show that ADA activity is increased in T2DM patients compared to that in non-diabetic patients, is positively correlated with blood glucose level, and that DPP4I has no additional specific effect on ADA activity, except for a glycemic control- or HbA1c-dependent effect.

The Role of Dipeptidyl Peptidase IV in Lung Metastasis of Breast Cancer Cells

DTIC Science & Technology

1999-05-01

Our studies focused on (1) cloning and sequencing of wild-type endothelial DPP IV (wtDPP IV) and preparation of truncated DPP IV ( tDPP IV); (2...that was identical to hepatic DPP IV. Acid extraction of rat lung yielded a tDPP IV, which was an effective inhibitor of breast cancer cell adhesion to

Visceral fat obesity increases serum DPP-4 levels in men with type 2 diabetes mellitus.

PubMed

Tanaka, Sayuri; Kanazawa, Ippei; Notsu, Masakazu; Sugimoto, Toshitsugu

2016-06-01

The relationship between serum DPP-4 level and visceral fat mass is still unclear in type 2 diabetes mellitus (T2DM). This study thus aimed to examine the association of visceral fat accumulation and metabolic syndrome with serum DPP-4 levels in T2DM. Visceral and subcutaneous fat areas were evaluated by performing computed tomography scan in 135 men with T2DM, who had never taken DPP-4 inhibitors or GLP-1 receptor agonists. We investigated the association between serum DPP-4 levels and visceral fat area as well as the presence of metabolic syndrome. Multiple regression analysis adjusted for age, duration of T2DM, body mass index, serum creatinine, and HbA1c showed that serum DPP-4 levels were positively associated with visceral fat area (β=0.25, p=0.04), but not subcutaneous fat area (β=-0.18, p=0.13). In logistic regression analyses adjusted for the confounding factors described above, serum DPP-4 levels were positively associated with visceral fat obesity and metabolic syndrome [odds ratio (OR)=1.63, 95% confidence interval (CI)=1.00-2.66 per standard deviation (SD) increase, p=0.04; OR=1.77, 95%CI=1.09-2.88 per SD increase, p=0.02, respectively]. The present study showed that serum DPP-4 level was positively and specifically associated with accumulation of visceral fat and the presence of metabolic syndrome in men with T2DM. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Suppression of Food Intake by Glucagon-Like Peptide-1 Receptor Agonists: Relative Potencies and Role of Dipeptidyl Peptidase-4

PubMed Central

Jessen, Lene; Aulinger, Benedikt A.; Hassel, Jonathan L.; Roy, Kyle J.; Smith, Eric P.; Greer, Todd M.; Woods, Stephen C.; Seeley, Randy J.

2012-01-01

Administration of the glucagon-like peptide-1 (GLP-1) receptor agonists GLP-1 and exendin-4 (Ex-4) directly into the central nervous system decreases food intake. But although Ex-4 potently suppresses food intake after peripheral administration, the effects of parenteral GLP-1 are variable and not as strong. A plausible explanation for these effects is the rapid inactivation of circulating GLP-1 by dipeptidyl peptidase-4 (DPP-4), an enzyme that does not alter Ex-4 activity. To test this hypothesis, we assessed the relative potency of Ex-4 and GLP-1 under conditions in which DPP-4 activity was reduced. Outbred rats, wild-type mice, and mice with a targeted deletion of DPP-4 (Dpp4−/−) were treated with GLP-1 alone or in combination with the DPP-4 inhibitor vildagliptin, Ex-4, or saline, and food intake was measured. GLP-1 alone, even at high doses, did not affect feeding in wild-type mice or rats but did reduce food intake when combined with vildagliptin or given to Dpp4−/− mice. Despite plasma clearance similar to DPP-4-protected GLP-1, equimolar Ex-4 caused greater anorexia than vildagliptin plus GLP-1. To determine whether supraphysiological levels of endogenous GLP-1 would suppress food intake if protected from DPP-4, rats with Roux-en-Y gastric bypass and significantly elevated postprandial plasma GLP-1 received vildagliptin or saline. Despite 5-fold greater postprandial GLP-1 in these animals, vildagliptin did not affect food intake in Roux-en-Y gastric bypass rats. Thus, in both mice and rats, peripheral GLP-1 reduces food intake significantly less than Ex-4, even when protected from DPP-4. These findings suggest distinct potencies of GLP-1 receptor agonists on food intake that cannot be explained by plasma pharmacokinetics. PMID:23033273

Structural studies of a bifunctional inhibitor of neprilysin and DPP-IV.

PubMed

Oefner, Christian; Pierau, Sabine; Schulz, Henk; Dale, Glenn E

2007-09-01

Neutral endopeptidase (NEP) is the major enzyme involved in the metabolic inactivation of a number of bioactive peptides including the enkephalins, substance P, endothelin, bradykinin and atrial natriuretic factor, as well as the incretin hormone glucagon-like peptide 1 (GLP-1), which is a potent stimulator of insulin secretion. The activity of GLP-1 is also rapidly abolished by the serine protease dipeptidyl peptidase IV (DPP-IV), which led to an elevated interest in inhibitors of this enzyme for the treatment of type II diabetes. A dual NEP/DPP-IV inhibitor concept is proposed, offering an alternative strategy for the treatment of type 2 diabetes. Here, the synthesis and crystal structures of the soluble extracellular domain of human NEP (residues 52-749) complexed with the NEP, competitive and potent dual NEP/DPP-IV inhibitor MCB3937 are described.

Determinants of saxagliptin use among patients with type 2 diabetes mellitus treated with oral anti-diabetic drugs.

PubMed

Saine, M Elle; Carbonari, Dena M; Newcomb, Craig W; Nezamzadeh, Melissa S; Haynes, Kevin; Roy, Jason A; Cardillo, Serena; Hennessy, Sean; Holick, Crystal N; Esposito, Daina B; Gallagher, Arlene M; Bhullar, Harshvinder; Strom, Brian L; Lo Re, Vincent

2015-04-02

The patterns and determinants of saxagliptin use among patients with type 2 diabetes mellitus (T2DM) are unknown in real-world settings. We compared the characteristics of T2DM patients who were new initiators of saxagliptin to those who were new initiators of non-dipeptidyl peptidase-4 (DPP-4) inhibitor oral anti-diabetic drugs (OADs) and identified factors associated with saxagliptin use. We conducted a cross-sectional study within the Clinical Practice Research Datalink (CPRD), The Health Improvement Network (THIN), US Medicare, and the HealthCore Integrated Research Database (HIRD(SM)) across the first 36 months of saxagliptin availability (29 months for US Medicare). Patients were included if they were: 1) ≥18 years old, 2) newly prescribed saxagliptin or a non-DPP-4 inhibitor OAD, and 3) enrolled in their respective database for 180 days. For each saxagliptin initiator, we randomly selected up to ten non-DPP-4 inhibitor OAD initiators matched on age, sex, and geographic region. Conditional logistic regression was used to identify determinants of saxagliptin use. We identified 64,079 saxagliptin initiators (CPRD: 1,962; THIN: 2,084; US Medicare: 51,976; HIRD(SM): 8,057) and 610,660 non-DPP-4 inhibitor OAD initiators (CPRD: 19,484; THIN: 19,936; US Medicare: 493,432; HIRD(SM): 77,808). Across all four data sources, prior OAD use, hypertension, and hyperlipidemia were associated with saxagliptin use. Saxagliptin initiation was also associated with hemoglobin A1c results >8% within the UK data sources, and a greater number of hemoglobin A1c measurements in the US data sources. In these UK and US data sources, initiation of saxagliptin was associated with prior poor glycemic control, prior OAD use, and diagnoses of hypertension and hyperlipidemia. ClinicalTrials.gov identifiers NCT01086280 , NCT01086293 , NCT01086319 , NCT01086306 , and NCT01377935.

Di-peptidyl peptidase-4 inhibitor sitagliptin protects vascular function in metabolic syndrome: possible role of epigenetic regulation.

PubMed

Cicek, Figen Amber; Amber, Cicek Figen; Tokcaer-Keskin, Zeynep; Zeynep, Tokcaer-Keskin; Ozcinar, Evren; Evren, Ozcinar; Bozkus, Yosuf; Yusuf, Bozkus; Akcali, Kamil Can; Can, Akcali Kamil; Turan, Belma; Belma, Turan

2014-08-01

Metabolic syndrome (MetS) is a complex medical disorder characterized by insulin resistance, hypertension, and high risk of coronary disease and stroke. Microvascular rarefaction and endothelial dysfunction have also been linked with MetS, and recent evidence from clinical studies supports the efficacy of incretin-based antidiabetic therapies for vascular protection in diabetes. Previous studies pointed out the importance of dipeptidyl peptidase-4 (DPP-4) inhibition in endothelial cells due to getting protection against metabolic pathologies. We therefore aimed to investigate the acute effects of a DPP-4 inhibitor, sitagliptin, on vascular function in rats with high-sucrose diet-induced MetS. In order to elucidate the mechanisms implicated in the effects of DPP-4 inhibition, we tested the involvement of NO pathway and epigenetic regulation in the MetS. Acute use of sitagliptin protects the vascular function in the rats with MetS in part due to NO pathway via restoring the depressed aortic relaxation responses mediated by receptors. Application of sitagliptin enhanced the depressed phosphorylation levels of both the endothelial NO synthase and the apoptotic status of protein kinase B, known as Akt, in endothelium-intact thoracic aorta from rats with MetS. One-hour application of sitagliptin on aortic rings from rats with MetS also induced remarkable histon posttranslational modifications such as increased expression of H3K27Me3, but not of H3K27Me2, resulting in an accumulation of the H3K27Me3. Our findings suggest that, in addition to its well-known hypoglycemic action, sitagliptin may also have beneficial effects on hyperglycemia-induced vascular changes in an endotheium-dependent manner. These present results with sitagliptin aside from the glycaemic control, may demonstrate its important role in the treatment of patients with MetS.

Effects of the combination of a dipeptidyl peptidase IV inhibitor and an insulin secretagogue on glucose and insulin levels in mice and rats.

PubMed

Yamazaki, Kazuto; Yasuda, Nobuyuki; Inoue, Takashi; Yamamoto, Eiichi; Sugaya, Yukiko; Nagakura, Tadashi; Shinoda, Masanobu; Clark, Richard; Saeki, Takao; Tanaka, Isao

2007-02-01

Several combination therapies have been tried for treating of type 2 diabetes to control more effectively fasting hyperglycemia and postprandial hyperglycemia. In this study, we have examined the effects of combining a novel, selective, and competitive dipeptidyl peptidase IV (DPP-IV) inhibitor, 3-but-2-ynyl-5-methyl-2-piperazin-1-yl-3,5-dihydro-4H-imidazo[4,5-d]pyridazin-4-one tosylate (E3024), with a representative of one of two types of insulin secretagogues, i.e., either glybenclamide (a sulfonylurea) or nateglinide (a rapid-onset/short-duration insulin secretagogue), on glucose and insulin levels in an oral glucose tolerance test (OGTT) using mice fed a high-fat diet. In addition, we have investigated the effects of these combinations on blood glucose levels in fasting rats. Two-way analysis of variance showed that the combination of E3024 and glybenclamide improved glucose tolerance additively and also caused a synergistic increase in insulin levels in the OGTT in mice fed a high-fat diet. In a similar way, the combination of E3024 and nateglinide ameliorated glucose tolerance additively and raised insulin levels additively. In fasting rats, coadministration of E3024 with glybenclamide or nateglinide treatment did not affect the glucose-lowering effects of the insulin secretagogues. Therefore, a DPP-IV inhibitor in combination with glybenclamide or nateglinide may be a promising option for the treatment of type 2 diabetes, and particularly, for controlling postprandial hyperglycemia in the clinic.

DPP-4 inhibitors for the treatment of type 2 diabetes: a methodology overview of systematic reviews.

PubMed

Ling, Juan; Ge, Long; Zhang, Ding-Hua; Wang, Yong-Feng; Xie, Zhuo-Lin; Tian, Jin-Hui; Xiao, Xiao-Hui; Yang, Ke-Hu

2018-06-01

To evaluate the methodological quality of systematic reviews (SRs), and summarize evidence of important outcomes from dipeptidyl peptidase-4 inhibitors (DPP4-I) in treating type 2 diabetes mellitus (T2DM). We included SRs of DPP4-I for the treatment of T2DM until January, 2018 by searching the Cochrane Library, PubMed, EMBASE and three Chinese databases. We evaluated the methodological qualities with the AMSTAR (Assessing the Methodological Quality of Systematic Reviews) tool and the GRADE (The Grading of Recommendations Assessment, Development and Evaluation) approach. Sixty-three SRs (a total of 2,603,140 participants) receiving DPP4-I for the treatment of T2DM were included. The results of AMSTAR showed that the lowest quality was "a list of studies (included and excluded) item" with only one (1.6%) study provided, followed by the "providing a priori design" item with only four (6.3%) studies conforming to this item, the next were "the status of publication (gray literature) used as an inclusion criterion item", with only 18 (28.9%) studies conforming to these items. Only seven (11.1%) studies scored more than nine points in AMSTAR, indicating high methodological quality. For GRADE, of the 128 outcomes, high quality evidence was provided in only 28 (21.9%), moderate in 70 (54.7%), low in 27 (21.1%), and very low in three (2.3%). The methodological quality of SRs of DPP4-I for type 2 diabetes mellitus is not high and there are common areas for improvement. Furthermore, the quality of evidence level is moderate and more high quality evidence is needed.

Pharmacokinetic, pharmacodynamic and clinical evaluation of saxagliptin in type 2 diabetes.

PubMed

Anderson, Rose; Hayes, Jennifer; Stephens, Jeffrey W

2016-01-01

Dipeptide peptidase-4 (DPP-4) inhibitors such as saxagliptin are established and efficacious oral therapies in the management of type 2 diabetes. These agents have the potential to confer significant benefits in glycemic control without the risk of weight gain and hypoglycemia, which may be associated with other medications used to treat type 2 diabetes. This review examines the pharmacokinetics, efficacy and tolerability of saxagliptin for the management of type 2 diabetes. Saxagliptin is routinely used in the management of type 2 diabetes as monotherapy, and in combination with other oral agents and insulin. Robust clinical trials have shown consistent improvements in glycated hemoglobin, fasting and postprandial glucose levels, with few adverse effects. The agent is well tolerated with low rates of hypoglycemia in the absence of insulin or sulphonylurea therapy.

Dipeptidyl peptidase-4 greatly contributes to the hydrolysis of vildagliptin in human liver.

PubMed

Asakura, Mitsutoshi; Fujii, Hideaki; Atsuda, Koichiro; Itoh, Tomoo; Fujiwara, Ryoichi

2015-04-01

The major metabolic pathway of vildagliptin in mice, rats, dogs, and humans is hydrolysis at the cyano group to produce a carboxylic acid metabolite M20.7 (LAY151), whereas the major metabolic enzyme of vildagliptin has not been identified. In the present study, we determined the contribution rate of dipeptidyl peptidase-4 (DPP-4) to the hydrolysis of vildagliptin in the liver. We performed hydrolysis assay of the cyano group of vildagliptin using mouse, rat, and human liver samples. Additionally, DPP-4 activities in each liver sample were assessed by DPP-4 activity assay using the synthetic substrate H-glycyl-prolyl-7-amino-4-methylcoumarin (Gly-Pro-AMC). M20.7 formation rates in liver microsomes were higher than those in liver cytosol. M20.7 formation rate was significantly positively correlated with the DPP-4 activity using Gly-Pro-AMC in liver samples (r = 0.917, P < 0.01). The formation of M20.7 in mouse, rat, and human liver S9 fraction was inhibited by sitagliptin, a selective DPP-4 inhibitor. These findings indicate that DPP-4 is greatly involved in vildagliptin hydrolysis in the liver. Additionally, we established stable single expression systems of human DPP-4 and its R623Q mutant, which is the nonsynonymous single-nucleotide polymorphism of human DPP-4, in human embryonic kidney 293 (HEK293) cells to investigate the effect of R623Q mutant on vildagliptin-hydrolyzing activity. M20.7 formation rate in HEK293 cells expressing human DPP-4 was significantly higher than that in control HEK293 cells. Interestingly, R623Q mutation resulted in a decrease of the vildagliptin-hydrolyzing activity. Our findings might be useful for the prediction of interindividual variability in vildagliptin pharmacokinetics. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

Gliptins in managing diabetes - Reviewing computational strategy.

PubMed

Sneha, P; Doss, C George Priya

2016-12-01

The pace of anti-diabetic drug discovery is very slow in spite of increasing rate of prevalence of Type 2 Diabetes which remains a major public health concern. Though extensive research steps are taken in the past decade, yet craves for better new treatment strategies to overcome the current scenario. One such general finding is the evolution of gliptins which discriminately inhibits DPP4 (Dipeptidyl peptidase-4) enzyme. Although the mechanism of action of gliptin is highly target oriented and accurate, still its long-term use stands unknown. This step calls for a fast, flexible, and cost-effective strategies to meet the demands of producing arrays of high-content lead compounds with improved efficiency for better clinical success. The present review highlights the available gliptins in the market and also other naturally occurring DPP4 enzyme inhibitors. Along with describing the known inhibitors and their origin in this review, we attempted to identify a probable new lead compounds using advanced computational techniques. In this context, computational methods that integrate the knowledge of proteins and drug responses were utilized in prioritizing targets and designing drugs towards clinical trials with better efficacy. The compounds obtained as a result of virtual screening were compared with the commercially available gliptin in the market to have better efficiency in the identification and validation of the potential DPP4 inhibitors. The combinatorial computational methods used in the present study identified Compound 1: 25022354 as promising inhibitor. Copyright © 2016 Elsevier Inc. All rights reserved.

Management Strategies for Posttransplant Diabetes Mellitus after Heart Transplantation: A Review

PubMed Central

Cehic, Matthew G.; Nundall, Nishant; Greenfield, Jerry R.

2018-01-01

Posttransplant diabetes mellitus (PTDM) is a well-recognized complication of heart transplantation and is associated with increased morbidity and mortality. Previous studies have yielded wide ranging estimates in the incidence of PTDM due in part to variable definitions applied. In addition, there is a limited published data on the management of PTDM after heart transplantation and a paucity of studies examining the effects of newer classes of hypoglycaemic drug therapies. In this review, we discuss the role of established glucose-lowering therapies and the rationale and emerging clinical evidence that supports the role of incretin-based therapies (glucagon like peptide- (GLP-) 1 agonists and dipeptidyl peptidase- (DPP-) 4 inhibitors) and sodium-glucose cotransporter 2 (SGLT2) inhibitors in the management of PTDM after heart transplantation. Recently published Consensus Guidelines for the diagnosis of PTDM will hopefully lead to more consistent approaches to the diagnosis of PTDM and provide a platform for the larger-scale multicentre trials that will be needed to determine the role of these newer therapies in the management of PTDM. PMID:29623219

Alogliptin after acute coronary syndrome in patients with type 2 diabetes.

PubMed

White, William B; Cannon, Christopher P; Heller, Simon R; Nissen, Steven E; Bergenstal, Richard M; Bakris, George L; Perez, Alfonso T; Fleck, Penny R; Mehta, Cyrus R; Kupfer, Stuart; Wilson, Craig; Cushman, William C; Zannad, Faiez

2013-10-03

To assess potentially elevated cardiovascular risk related to new antihyperglycemic drugs in patients with type 2 diabetes, regulatory agencies require a comprehensive evaluation of the cardiovascular safety profile of new antidiabetic therapies. We assessed cardiovascular outcomes with alogliptin, a new inhibitor of dipeptidyl peptidase 4 (DPP-4), as compared with placebo in patients with type 2 diabetes who had had a recent acute coronary syndrome. We randomly assigned patients with type 2 diabetes and either an acute myocardial infarction or unstable angina requiring hospitalization within the previous 15 to 90 days to receive alogliptin or placebo in addition to existing antihyperglycemic and cardiovascular drug therapy. The study design was a double-blind, noninferiority trial with a prespecified noninferiority margin of 1.3 for the hazard ratio for the primary end point of a composite of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. A total of 5380 patients underwent randomization and were followed for up to 40 months (median, 18 months). A primary end-point event occurred in 305 patients assigned to alogliptin (11.3%) and in 316 patients assigned to placebo (11.8%) (hazard ratio, 0.96; upper boundary of the one-sided repeated confidence interval, 1.16; P<0.001 for noninferiority). Glycated hemoglobin levels were significantly lower with alogliptin than with placebo (mean difference, -0.36 percentage points; P<0.001). Incidences of hypoglycemia, cancer, pancreatitis, and initiation of dialysis were similar with alogliptin and placebo. Among patients with type 2 diabetes who had had a recent acute coronary syndrome, the rates of major adverse cardiovascular events were not increased with the DPP-4 inhibitor alogliptin as compared with placebo. (Funded by Takeda Development Center Americas; EXAMINE ClinicalTrials.gov number, NCT00968708.).

Blood Glucagon Levels Predict the Hemoglobin A1c Response to Saxagliptin in Patients with Type 2 Diabetes Inadequately Controlled with Metformin.

PubMed

Liu, Hao; Hu, Yun; Li, Feng-Fei; Liu, Bing-Li; Su, Xiao-Fei; Ma, Jian-Hua

2016-12-01

Dipeptidyl peptidase-4 (DPP-4) inhibitors are widely used as second-option medications when metformin fails. Variance of the glycated hemoglobin (HbA1c) response to DPP-4 inhibitions in patients with type 2 diabetes mellitus (T2DM) has been observed, but the characteristics which predict the response to DPP-4 inhibitor therapy are unclear. The aim of this study was to investigate the characteristics of α- and β-cell functions which might predict the efficacy of saxagliptin and facilitate personalization of treatment. We studied 60 patients with T2DM who had inadequate glycemic control [HbA1c7.0-13.0% (53-119 mmol/mol)) with metformin alone. The patients were treated with saxagliptin (5 mg, daily) and metformin (1000-2000 mg as former) for 12 weeks. Oral glucose tolerance tests were carried out at baseline and endpoint to evaluate α- and β-cell functions, and blood C-peptide, insulin, glucagon levels were tested. Blood glucose, HbA1c and weight were also observed. Significant reduction of weight, HbA1c and glucagon was observed after 12-week treatment, while C-peptide, insulin and homeostasis model assessment-β increased (P < 0.05). Linear regression and receiver operating characteristic analysis showed that baseline HbA1c and 30 min-glucagon were correlated with the HbA1c response to saxagliptin, while the weight loss was correlated with gender, age and fasting-insulin level. Further analysis showed the 30 min-glucagon of 49.1 pmol/L was the optimal cutoff value to predict the efficacy of saxagliptin. Saxagliptin added to metformin significantly improved glycemic control and α- and β-cell function. Blood glucagon level was a good predicting factor for the HbA1c response to saxagliptin, and it will help appropriate patient selection. Chinese Clinical Trial Register identifier, ChiCTR-PPR-15007045.

Dapagliflozin and saxagliptin tablets for adults with type 2 diabetes.

PubMed

Scheen, André J

2017-12-01

Saxagliptin (a dipeptidyl peptidase-4 inhibitor, DPP-4i) and dapagliflozin (a sodium-glucose cotransporter type 2 inhibitor, SGLT2i) improve glucose control in type 2 diabetes (T2D) through different potentially complementary mechanisms, thus offering the opportunity for a combined therapy. Area covered: The characteristics of the saxagliptin/dapagliflozin combination are analysed, focusing on: 1) pharmacokinetic and pharmacodynamic properties; 2) efficacy and safety in phase III trials with concurrent and sequential add-on therapy; and 3) potential use in clinical practice, including in special populations (cardiovascular disease, heart failure, chronic kidney disease, elderly). Expert commentary: Conclusions drawn from clinical trials investigating combination with the separate drugs are considered to apply to the fixed-dose combination (FDC) that demonstrates bioequivalence. Dual saxagliptin/dapagliflozin therapy is more potent than either monotherapy and can be used as an initial combination or a stepwise sequential approach. Dual therapy is generally well tolerated and may be used in special populations, with some limitations because of the presence of dapagliflozin. However, the latter may offer some advantages because of multiple effects attributed to SGLT2i. The best place of this dual combination for the management of T2D and the profile of patients who will make the most of this combined therapy remains to be defined.

Chronic administration of DSP-7238, a novel, potent, specific and substrate-selective DPP IV inhibitor, improves glycaemic control and beta-cell damage in diabetic mice.

PubMed

Furuta, Y; Horiguchi, M; Sugaru, E; Ono-Kishino, M; Otani, M; Sakai, M; Masui, Y; Tsuchida, A; Sato, Y; Takubo, K; Hochigai, H; Kimura, H; Nakahira, H; Nakagawa, T; Taiji, M

2010-05-01

The purpose of this study is to assess the in vitro enzyme inhibition profile of DSP-7238, a novel non-cyanopyrrolidine dipeptidyl peptidase (DPP) IV inhibitor and to evaluate the acute and chronic effects of this compound on glucose metabolism in two different mouse models of type 2 diabetes. The in vitro enzyme inhibition profile of DSP-7238 was assessed using plasma and recombinant enzymes including DPP IV, DPP II, DPP8, DPP9 and fibroblast activation protein alpha (FAPalpha) with fluorogenic substrates. The inhibition type was evaluated based on the Lineweaver-Burk plot. Substrate selectivity of DSP-7238 and comparator DPP IV inhibitors (vildagliptin, sitagliptin, saxagliptin and linagliptin) was evaluated by mass spectrometry based on the changes in molecular weight of peptide substrates caused by release of N-terminal dipeptides. In the in vivo experiments, high-fat diet-induced obese (DIO) mice were subjected to oral glucose tolerance test (OGTT) following a single oral administration of DSP-7238. To assess the chronic effects of DSP-7238 on glycaemic control and pancreatic beta-cell damage, DSP-7238 was administered for 11 weeks to mice made diabetic by a combination of high-fat diet (HFD) and a low-dose of streptozotocin (STZ). After the dosing period, HbA1c was measured and pancreatic damage was evaluated by biological and histological analyses. DSP-7238 and sitagliptin both competitively inhibited recombinant human DPP IV (rhDPP IV) with K(i) values of 0.60 and 2.1 nM respectively. Neither vildagliptin nor saxagliptin exhibited competitive inhibition of rhDPP IV. DSP-7238 did not inhibit DPP IV-related enzymes including DPP8, DPP9, DPP II and FAPalpha, whereas vildagliptin and saxagliptin showed inhibition of DPP8 and DPP9. Inhibition of glucagon-like peptide-1 (GLP-1) degradation by DSP-7238 was apparently more potent than its inhibition of chemokine (C-X-C motif) ligand 10 (IP-10) or chemokine (C-X-C motif) ligand 12 (SDF-1alpha) degradation. In contrast, vildagliptin and saxagliptin showed similar degree of inhibition of degradation for all the substrates tested. Compared to treatment with the vehicle, single oral administration of DSP-7238 dose-dependently decreased plasma DPP IV activity and improved glucose tolerance in DIO mice. In addition, DSP-7238 significantly decreased HbA1c and ameliorated pancreatic damage following 11 weeks of chronic treatment in HFD/STZ mice. We have shown in this study that DSP-7238 is a potent DPP IV inhibitor that has high specificity for DPP IV and substrate selectivity against GLP-1. We have also found that chronic treatment with DSP-7238 improves glycaemic control and ameliorates beta-cell damage in a mouse model with impaired insulin sensitivity and secretion. These findings indicate that DSP-7238 may be a new therapeutic agent for the treatment of type 2 diabetes.

The CTRB1/2 Locus Affects Diabetes Susceptibility and Treatment via the Incretin Pathway

PubMed Central

‘t Hart, Leen M.; Fritsche, Andreas; Nijpels, Giel; van Leeuwen, Nienke; Donnelly, Louise A.; Dekker, Jacqueline M.; Alssema, Marjan; Fadista, Joao; Carlotti, Françoise; Gjesing, Anette P.; Palmer, Colin N.A.; van Haeften, Timon W.; Herzberg-Schäfer, Silke A.; Simonis-Bik, Annemarie M.C.; Houwing-Duistermaat, Jeanine J.; Helmer, Quinta; Deelen, Joris; Guigas, Bruno; Hansen, Torben; Machicao, Fausto; Willemsen, Gonneke; Heine, Robert J.; Kramer, Mark H.H.; Holst, Jens J.; de Koning, Eelco J.P.; Häring, Hans-Ulrich; Pedersen, Oluf; Groop, Leif; de Geus, Eco J.C.; Slagboom, P. Eline; Boomsma, Dorret I.; Eekhoff, Elisabeth M.W.; Pearson, Ewan R.; Diamant, Michaela

2013-01-01

The incretin hormone glucagon-like peptide 1 (GLP-1) promotes glucose homeostasis and enhances β-cell function. GLP-1 receptor agonists (GLP-1 RAs) and dipeptidyl peptidase-4 (DPP-4) inhibitors, which inhibit the physiological inactivation of endogenous GLP-1, are used for the treatment of type 2 diabetes. Using the Metabochip, we identified three novel genetic loci with large effects (30–40%) on GLP-1–stimulated insulin secretion during hyperglycemic clamps in nondiabetic Caucasian individuals (TMEM114; CHST3 and CTRB1/2; n = 232; all P ≤ 8.8 × 10−7). rs7202877 near CTRB1/2, a known diabetes risk locus, also associated with an absolute 0.51 ± 0.16% (5.6 ± 1.7 mmol/mol) lower A1C response to DPP-4 inhibitor treatment in G-allele carriers, but there was no effect on GLP-1 RA treatment in type 2 diabetic patients (n = 527). Furthermore, in pancreatic tissue, we show that rs7202877 acts as expression quantitative trait locus for CTRB1 and CTRB2, encoding chymotrypsinogen, and increases fecal chymotrypsin activity in healthy carriers. Chymotrypsin is one of the most abundant digestive enzymes in the gut where it cleaves food proteins into smaller peptide fragments. Our data identify chymotrypsin in the regulation of the incretin pathway, development of diabetes, and response to DPP-4 inhibitor treatment. PMID:23674605

The consumer welfare implications of governmental policies and firm strategy in markets for medicines.

PubMed

Chatterjee, Chirantan; Kubo, Kensuke; Pingali, Viswanath

2015-12-01

This paper empirically examines the consumer welfare implications of changes in government policies related to patent protection and compulsory licensing in the Indian market for oral anti-diabetic (OAD) medicines. In contrast to previous studies on the impact of pharmaceutical patents in India, we observe, and estimate the welfare effects accruing from differential pricing and voluntary licensing strategies of patent-holding innovator firms. Three novel molecules belonging to the dipeptidyl peptidase-4 (DPP-4) inhibitor class of OADs have been launched in India by the patent holders, at lower prices than those prevailing in the developed countries. Using aggregate market transaction data, we structurally estimate demand and supply and use the parameter estimates in our model to simulate consumer welfare under various counterfactual scenarios. Our results suggest that the introduction of DPP-4 inhibitors generated a consumer surplus gain of around 7.6 cents per day for a typical DPP-4 inhibitor user under the existing differential pricing and voluntary licensing strategies. If the innovators decide to price at developed-country levels, this surplus is eliminated almost entirely. The issuance of compulsory licensing does not always improve consumer welfare because if innovators defer or delay the introduction of new drugs in response, the loss in consumer welfare could be substantial. Copyright © 2015 Elsevier B.V. All rights reserved.

Changes in Adenosine Deaminase Activity in Patients with Type 2 Diabetes Mellitus and Effect of DPP-4 Inhibitor Treatment on ADA Activity

PubMed Central

Lee, Jae-Geun; Kang, Dong Gu; Yu, Jung Re; Kim, Youngree; Kim, Jinsoek; Koh, Gwanpyo

2011-01-01

Background Dipeptidyl peptidase 4 (DPP-4, also known as CD26) binds with adenosine deaminase (ADA) to activate T lymphocytes. Here, we investigated whether ADA activity is specifically affected by treatment with DPP-4 inhibitor (DPP4I) compared with other anti-diabetic agents. Methods Fasting ADA activity, in addition to various metabolic and biochemical parameters, were measured in 262 type 2 diabetes mellitus (T2DM) patients taking various anti-diabetic agents and in 46 non-diabetic control subjects. Results ADA activity was increased in T2DM patients compared with that in non-diabetic control subjects (mean±standard error, 23.1±0.6 U/L vs. 18.6±0.8 U/L; P<0.05). ADA activity was correlated with fasting plasma glucose (r=0.258, P<0.05), HbA1c (r=0.208, P<0.05), aspartate aminotransferase (r=0.325, P<0.05), and alanine aminotransferase (r=0.248, P<0.05). Compared with the well-controlled T2DM patients (HbA1c<7%), the poorly controlled group (HbA1c>9%) showed significantly increased ADA activity (21.1±0.8 U/L vs. 25.4±1.6 U/L; P<0.05). The effect of DPP4I on ADA activity in T2DM patients did not differ from those of other oral anti-diabetic agents or insulin. T2DM patients on metformin monotherapy showed a lower ADA activity (20.9±1.0 U/L vs. 28.1±2.8 U/L; P<0.05) compared with that of those on sulfonylurea monotherapy. Conclusion Our results show that ADA activity is increased in T2DM patients compared to that in non-diabetic patients, is positively correlated with blood glucose level, and that DPP4I has no additional specific effect on ADA activity, except for a glycemic control- or HbA1c-dependent effect. PMID:21738897

Relationship between deterioration of glycated hemoglobin-lowering effects in dipeptidyl peptidase-4 inhibitor monotherapy and dietary habits: Retrospective analysis of Japanese individuals with type 2 diabetes.

PubMed

Kuwata, Hitoshi; Okamoto, Saki; Seino, Yusuke; Murotani, Kenta; Tatsuoka, Hisato; Usui, Ryota; Hamamoto, Yoshiyuki; Kurose, Takeshi; Seino, Yutaka; Yabe, Daisuke

2017-11-24

The present study was designed to assess possible relationships between deterioration of the glycated hemoglobin (HbA1c)-lowering effects in dipeptidyl peptidase-4 inhibitor (DPP4i) monotherapy and macronutrient intake among individuals with type 2 diabetes. Type 2 diabetes patients who began and continued DPP4i monotherapy without any prescription change for 1 year were retrospectively stratified into two groups: (i) patients who maintained their HbA1c levels during the 0.5- to 1-year period after DPP4i initiation (group A, ΔHbA1c [1-0.5 year] <0.4%, n = 53); and (ii) those whose HbA1c levels increased [group B, ΔHbA1c (1-0.5 year] ≥0.4%, n = 10). Group B had significantly higher ΔHbA1c (1-0.5 year), Δbodyweight (1-0.5 year) and fat intake, especially of saturated and monounsaturated fats; the carbohydrate and protein intake were similar between groups. Multiple regression analyses showed that fat intake, especially saturated fat intake, was significantly correlated with ΔHbA1c (1-0.5 year). Thus, dietary habits, especially saturated fat intake, might well contribute to deterioration of the HbA1c-lowering effects in DPP4i monotherapy. © 2017 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.

Unique and Highly Selective Anticytomegalovirus Activities of Artemisinin-Derived Dimer Diphenyl Phosphate Stem from Combination of Dimer Unit and a Diphenyl Phosphate Moiety

PubMed Central

He, Ran; Forman, Michael; Mott, Bryan T.; Venkatadri, Rajkumar; Posner, Gary H.

2013-01-01

We report that the artemisinin-derived dimer diphenyl phosphate (DPP; dimer 838) is the most selective inhibitor of human cytomegalovirus (CMV) replication among a series of artemisinin-derived monomers and dimers. Dimer 838 was also unique in being an irreversible CMV inhibitor. The peroxide unit within artemisinins' chemical structures is critical to their activities, and its absence results in loss of anti-CMV activities. Surprisingly, the deoxy dimer of 838 retained modest anti-CMV activity, suggesting that the DPP moiety of dimer 838 contributes to its anti-CMV activities. DPP alone did not inhibit CMV replication, but triphenyl phosphate (TPP) had modest CMV inhibition, although its selectivity index was low. Artemisinin DPP derivatives dimer 838 and monomer diphenyl phosphate (compound 558) showed stronger CMV inhibition and a higher selectivity index than their analogs lacking the DPP unit. An add-on and removal assay revealed that removing DPP derivatives (compounds 558 and 838) but not the non-DPP backbones (artesunate and compound 606) at 24 h postinfection (hpi) already resulted in dominant CMV inhibition. CMV inhibition was fully irreversible with 838 and partially irreversible with 558, while non-DPP artemisinins were reversible inhibitors. While all artemisinin derivatives and TPP reduced the expression of the CMV immediate early 2 (IE2), UL44, and pp65 proteins at or after 48 hpi, only TPP inhibited the expression of both IE1 and IE2. Combination of a non-DPP dimer (compound 606) with TPP was synergistic in CMV inhibition, while ganciclovir and TPP were additive. Although TPP shared structural similarity with monomer DPP (compound 558) and dimer DPP (compound 838), its pattern of CMV inhibition was significantly different from the patterns of the artemisinins. These findings demonstrate that the DPP group contributes to the unique activities of compound 838. PMID:23774439

Discovery of DPP IV inhibitors by pharmacophore modeling and QSAR analysis followed by in silico screening.

PubMed

Al-Masri, Ihab M; Mohammad, Mohammad K; Taha, Mutasem O

2008-11-01

Dipeptidyl peptidase IV (DPP IV) deactivates the natural hypoglycemic incretin hormones. Inhibition of this enzyme should restore glucose homeostasis in diabetic patients making it an attractive target for the development of new antidiabetic drugs. With this in mind, the pharmacophoric space of DPP IV was explored using a set of 358 known inhibitors. Thereafter, genetic algorithm and multiple linear regression analysis were employed to select an optimal combination of pharmacophoric models and physicochemical descriptors that yield selfconsistent and predictive quantitative structure-activity relationships (QSAR) (r(2) (287)=0.74, F-statistic=44.5, r(2) (BS)=0.74, r(2) (LOO)=0.69, r(2) (PRESS) against 71 external testing inhibitors=0.51). Two orthogonal pharmacophores (of cross-correlation r(2)=0.23) emerged in the QSAR equation suggesting the existence of at least two distinct binding modes accessible to ligands within the DPP IV binding pocket. Docking experiments supported the binding modes suggested by QSAR/pharmacophore analyses. The validity of the QSAR equation and the associated pharmacophore models were established by the identification of new low-micromolar anti-DPP IV leads retrieved by in silico screening. One of our interesting potent anti-DPP IV hits is the fluoroquinolone gemifloxacin (IC(50)=1.12 muM). The fact that gemifloxacin was recently reported to potently inhibit the prodiabetic target glycogen synthase kinase 3beta (GSK-3beta) suggests that gemifloxacin is an excellent lead for the development of novel dual antidiabetic inhibitors against DPP IV and GSK-3beta.

Sarcopenia in Elderly Diabetic Patients: Role of Dipeptidyl Peptidase 4 Inhibitors.

PubMed

Rizzo, Maria Rosaria; Barbieri, Michelangela; Fava, Ilaria; Desiderio, Manuela; Coppola, Carla; Marfella, Raffaele; Paolisso, Giuseppe

2016-10-01

Our study aimed to investigate the effect of dipeptidyl peptidase 4 inhibitors (DPP4-I) on sarcopenic parameters in elderly type 2 diabetic patients. All elderly diabetic patients were invited to present themselves at our outpatient Geriatric Centre to undergo to evaluation of glycemic, inflammatory, and sarcopenic parameters and to perform a meal test for glucagon-like peptide-1 analogue (GLP-1) activity evaluation. According to European Working Group on Sarcopenia in Older People (EWGSOP) criteria, sarcopenic parameters were assessed by bioelectrical impedance analysis (BIA) and Kern dynamometer and 4-m gait speed tests. All patients received standardized meals for the assessment of postprandial levels of GLP-1 activity. Data of 80 elderly diabetic patients treated with oral glucose-lowering drugs (DPP4-I or Sulfonylureas Group) for at least 24 months before enrollment were analyzed. The DPP4-I Group showed appropriate glycemic control, lower levels of inflammatory parameters, a significant and greater increase, during interprandial periods, of GLP-1 activity, and better sarcopenic parameters (fat-free mass, skeletal muscle mass, and related indices, muscle strength, and gait speed) compared with the Sulfonylureas Group. Univariate analysis showed that sarcopenic parameters correlated with glycemic control and with GLP-1 area under the curve values. Multivariate analysis confirms these relationships. The results are consistent with the hypothesis that DPP4-I use might have a positive effect on the loss of muscle mass and its function. Copyright © 2016 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

The DPP4 Inhibitor Linagliptin Protects from Experimental Diabetic Retinopathy.

PubMed

Dietrich, Nadine; Kolibabka, Matthias; Busch, Stephanie; Bugert, Petra; Kaiser, Ulrike; Lin, Jihong; Fleming, Thomas; Morcos, Michael; Klein, Thomas; Schlotterer, Andrea; Hammes, Hans-Peter

2016-01-01

Dipeptidyl peptidase 4 (DPP4) inhibitors improve glycemic control in type 2 diabetes, however, their influence on the retinal neurovascular unit remains unclear. Vasculo- and neuroprotective effects were assessed in experimental diabetic retinopathy and high glucose-cultivated C. elegans, respectively. In STZ-diabetic Wistar rats (diabetes duration of 24 weeks), DPP4 activity (fluorometric assay), GLP-1 (ELISA), methylglyoxal (LC-MS/MS), acellular capillaries and pericytes (quantitative retinal morphometry), SDF-1a and heme oxygenase-1 (ELISA), HMGB-1, Iba1 and Thy1.1 (immunohistochemistry), nuclei in the ganglion cell layer, GFAP (western blot), and IL-1beta, Icam1, Cxcr4, catalase and beta-actin (quantitative RT-PCR) were determined. In C. elegans, neuronal function was determined using worm tracking software. Linagliptin decreased DPP4 activity by 77% and resulted in an 11.5-fold increase in active GLP-1. Blood glucose and HbA1c were reduced by 13% and 14% and retinal methylglyoxal by 66%. The increase in acellular capillaries was diminished by 70% and linagliptin prevented the loss of pericytes and retinal ganglion cells. The rise in Iba-1 positive microglia was reduced by 73% with linagliptin. In addition, the increase in retinal Il1b expression was decreased by 65%. As a functional correlate, impairment of motility (body bending frequency) was significantly prevented in C. elegans. Our data suggest that linagliptin has a protective effect on the microvasculature of the diabetic retina, most likely due to a combination of neuroprotective and antioxidative effects of linagliptin on the neurovascular unit.

The DPP-4 inhibitor anagliptin ameliorates hypercholesterolemia in hypercholesterolemic mice via inhibition of intestinal cholesterol transport.

PubMed

Goto, Moritaka; Furuta, Shinji; Yamashita, Satoko; Hashimoto, Hiroyuki; Yano, Wataru; Inoue, Noriyuki; Kato, Noriaki; Kaku, Kohei

2018-05-13

Recent data showed that DPP-4 inhibitors exert a lipid-lowering effect in diabetic patients. However, the mechanism of action is not yet clearly understood. We investigated the effect of anagliptin on cholesterol metabolism and transport in the small intestine using non-diabetic hyperlipidemic animals, to clarify the mechanisms underlying the cholesterol-lowering action. Male ApoE-deficient mice were orally administered anagliptin in the normal chow. Serum cholesterol levels and lipoprotein profiles were measured, and cholesterol transport was assessed by measuring the radioactivity in the tissues after oral loading of 14 C-labeled cholesterol ( 14 C-Chol). In additional experiments, effects of exendin-4 in mice and of anagliptin in DPP-4-deficient rats were assessed. Effect on target gene expressions in the intestine were analyzed by qPCR in normal mice. The serum total and non-HDL cholesterol concentrations decreased after anagliptin treatment in the ApoE-deficient mice. The cholesterol-lowering effect was predominantly observed in the chylomicron fraction. The plasma 14 C-Chol radioactivity was significantly decreased by 26% at 2 hours after cholesterol loading, and the fecal 14 C-Chol excretion was significantly increased by 38% at 72 hours. The aforementioned effects on cholesterol transport were abrogated in rats lacking DPP-4 activity, and exendin-4 had no effect on the 14 C-Chol transport in ApoE-deficient mice. Furthermore, significant decreases of the intestinal cholesterol transport related MTTP, ACAT2, ApoA2 and ApoC2 mRNA expressions were observed in the mice treated with repeated doses of anagliptin. These findings suggest that anagliptin may exert a cholesterol-lowering action via DPP-4-dependent and GLP-1-independent suppression of intestinal cholesterol transport. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Clinical Safety and Tolerability of Vildagliptin - Insights from Randomised Trials, Observational Studies and Post-marketing Surveillance.

PubMed

Mathieu, Chantal; Kozlovski, Plamen; Paldánius, Päivi M; Foley, James E; Modgill, Vikas; Evans, Marc; Serban, Carmen

2017-08-01

Vildagliptin is one of the most extensively studied dipeptidyl peptidase-4 (DPP-4) inhibitors in terms of its clinical utility. Over the last decade, a vast panorama of evidence on the benefit-risk profile of vildagliptin has been generated in patients with type 2 diabetes mellitus (T2DM). In this article, we review the cumulative evidence on the safety of vildagliptin from the clinical development programme, as well as reports of rare adverse drug reactions detected during the post-marketing surveillance of the drug. Across clinical studies, the overall safety and tolerability profile of vildagliptin was similar to placebo, and it was supported by real-world data in a broad population of patients with T2DM, making DPP-4 inhibitors, like vildagliptin, a safe option for managing patients with T2DM.

Profile of saxagliptin in the treatment of type 2 diabetes: focus on Japanese patients.

PubMed

Konya, Hiroyuki; Yano, Yuzo; Matsutani, Satoshi; Tsunoda, Taku; Ikawa, Takashi; Kusunoki, Yoshiki; Matsuo, Toshihiro; Miuchi, Masayuki; Katsuno, Tomoyuki; Hamaguchi, Tomoya; Miyagawa, Jun-Ichiro; Namba, Mitsuyoshi

2014-01-01

Saxagliptin is a selective and potent dipeptidyl peptidase (DPP)-4 inhibitor, approved as an adjunct to diet and exercise to improve glycemic control in type 2 diabetes mellitus (T2DM) in the USA on July 2009, and had been launched globally in over 86 countries by September 2013. In patients with T2DM, once-daily administration of saxagliptin before breakfast achieves sustained inhibition of plasma DPP-4 activity and reduction of postprandial hyperglycemia, including after dinner, associated with an increase in plasma glucagon-like peptide-1 levels. This paper reviews the safety and efficacy of saxagliptin in Japanese patients with T2DM. The clinical development study in Japan supported its usefulness for the disease. Saxagliptin 1, 2.5, and 5 mg led to significant improvements in glycated hemoglobin (HbA1c), and was generally well tolerated. Treatment with saxagliptin 5 mg induced a sustained reduction in HbA1c over 52 weeks. Long-term combination therapy with saxagliptin and other oral hypoglycemic agents also provided sustained glycemic control and was well tolerated for up to 52 weeks. Saxagliptin as add-on to sulfonylureas or glinides has a tendency to increase hypoglycemia, but not with other oral antidiabetic agents, such as α-glucosidase inhibitors, metformin, or thiazolidinediones. The results of clinical trials have confirmed the long-term efficacy and safety of saxagliptin monotherapy as well as its use as add-on combination therapy, and support its usefulness as a therapeutic agent for T2DM. Saxagliptin has less concern for hypoglycemia and weight gain, which often becomes problematic in routine care of T2DM. Meta-analysis of clinical trials in the USA showed no evidence of increased risk of cardiovascular events associated with saxagliptin, suggesting the superior of saxagliptin in terms of safety. Recently, investigators in the SAVOR-TIMI (Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus-Thrombolysis in Myocardial Infarction) 53 study suggested that DPP-4 inhibition with saxagliptin did not increase or decrease the rate of ischemic events, although the rate of hospitalization for heart failure was increased. Although saxagliptin improves glycemic control, other approaches are necessary to reduce cardiovascular risk in patients with diabetes. Saxagliptin is applicable for various pathological conditions, and is considered to be clinically significant as a new therapeutic option for Japanese patients with T2DM.

Role of vildagliptin in managing type 2 diabetes mellitus in the elderly.

PubMed

Halimi, S; Raccah, D; Schweizer, A; Dejager, S

2010-07-01

The prevalence of type 2 diabetes (T2DM) increases with age. Older patients have an increased likelihood for T2DM-related morbidity and mortality. The objective of this review is to provide an overview of the challenges in managing T2DM in the elderly, with an emphasis on prevention of hypoglycaemia and the role of the DPP-4 inhibitor vildagliptin in this patient population. A search of PubMed was conducted (from 2003 to 2010) to identify English-language articles relevant to the management of elderly patients with T2DM, with an emphasis on vildagliptin treatment. A limitation of this review is that it does not provide an overview of the entire class of dipeptidyl-peptidase-4 (DPP-4) inhibitors. Management of T2DM in elderly patients is complicated by numerous factors, including a high prevalence of cardiovascular risk factors and other comorbidities and a high frequency of polypharmacy issues. Hypoglycaemia may pose the greatest barrier to optimal glycaemic control in elderly patients, who are less likely to recognise and respond to hypoglycaemic episodes, leading to increased frequency and severity of events. Data on the DPP-4 inhibitor vildagliptin indicate that reductions in A1C in elderly patients are at least as good as those observed in younger patients and are achieved with minimal risk of hypoglycaemia. T2DM in older individuals is associated with relative hyperglucagonaemia and elevated postprandial glucose (PPG). Vildagliptin treatment appears to address both these defects. Vildagliptin improves the ability of alpha- and beta-cells to respond appropriately to changes in plasma glucose levels. This, in the face of high glucose levels, results in reduced inappropriate glucagon secretion and PPG excursions. In the face of low glucose, however, the protective glucagon response is well-preserved. These factors help explain the efficacy and minimal risk of hypoglycaemia observed with vildagliptin in elderly patients. The elderly population with T2DM poses unique treatment challenges and have not been particularly well-represented in clinical trials, highlighting the need for additional studies to better define appropriate glucose targets and to ascertain the best strategies for achieving and maintaining appropriate glycaemic levels. Because vildagliptin does not expose patients to hypoglycaemic risk, it seems particularly suited to oral therapy of T2DM in the elderly.

Diketopyrrolopyrrole-based carbon dots for photodynamic therapy.

PubMed

He, Haozhe; Zheng, Xiaohua; Liu, Shi; Zheng, Min; Xie, Zhigang; Wang, Yong; Yu, Meng; Shuai, Xintao

2018-06-01

The development of a simple and straightforward strategy to synthesize multifunctional carbon dots for photodynamic therapy (PDT) has been an emerging focus. In this work, diketopyrrolopyrrole-based fluorescent carbon dots (DPP CDs) were designed and synthesized through a facile one-pot hydrothermal method by using diketopyrrolopyrrole (DPP) and chitosan (CTS) as raw materials. DPP CDs not only maintained the ability of DPP to generate singlet oxygen (1O2) but also have excellent hydrophilic properties and outstanding biocompatibility. In vitro and in vivo experiments demonstrated that DPP CDs greatly inhibited the growth of tumor cells under laser irradiation (540 nm). This study highlights the potential of the rational design of CDs for efficient cancer therapy.

Hibiscus sabdariffa polyphenols prevent palmitate-induced renal epithelial mesenchymal transition by alleviating dipeptidyl peptidase-4-mediated insulin resistance.

PubMed

Huang, Chien-Ning; Wang, Chau-Jong; Yang, Yi-Sun; Lin, Chih-Li; Peng, Chiung-Huei

2016-01-01

Diabetic nephropathy has a significant socioeconomic impact, but its mechanism is unclear and needs to be examined. Hibiscus sabdariffa polyphenols (HPE) inhibited high glucose-induced angiotensin II receptor-1 (AT-1), thus attenuating renal epithelial mesenchymal transition (EMT). Recently, we reported HPE inhibited dipeptidyl-peptidase-4 (DPP-4, the enzyme degrades type 1 glucagon-like peptide (GLP-1)), which mediated insulin resistance signals leading to EMT. Since free fatty acids can realistically bring about insulin resistance, using the palmitate-stimulated cell model in contrast with type 2 diabetic rats, in this study we examined if insulin resistance causes renal EMT, and the preventive effect of HPE. Our findings reveal that palmitate hindered 30% of glucose uptake. Treatment with 1 mg mL(-1) of HPE and the DPP-4 inhibitor linagliptin completely recovered insulin sensitivity and palmitate-induced signal cascades. HPE inhibited DPP-4 activity without altering the levels of DPP-4 and the GLP-1 receptor (GLP-1R). HPE decreased palmitate-induced phosphorylation of Ser307 of insulin receptor substrate-1 (pIRS-1 (S307)), AT-1 and vimentin, while increasing phosphorylation of phosphatidylinositol 3-kinase (pPI3K). IRS-1 knockdown revealed its essential role in mediating downstream AT-1 and EMT. In type 2 diabetic rats, it suggests that HPE concomitantly decreased the protein levels of DPP-4, AT-1, vimentin, and fibronectin, but reversed the in vivo compensation of GLP-1R. In conclusion, HPE improves insulin sensitivity by attenuating DPP-4 and the downstream signals, thus decreasing AT-1-mediated tubular-interstitial EMT. HPE could be an adjuvant to prevent diabetic nephropathy.

The dipeptidyl peptidase-4 inhibitor Saxagliptin improves function of circulating pro-angiogenic cells from type 2 diabetic patients

PubMed Central

2014-01-01

Background Type 2 diabetes (T2D) is associated with reduction and dysfunction of circulating pro-angiogenic cells (PACs). DPP-4 inhibitors, a class of oral agents for T2D, might possess pleiotropic vasculoprotective activities. Herein, we tested whether DPP-4 inhibition with Saxagliptin affects the function of circulating PACs from T2D and healthy subjects. Methods PACs were isolated from T2D (n = 20) and healthy (n = 20) subjects. Gene expression, clonogenesis, proliferation, adhesion, migration and tubulisation were assessed in vitro by incubating PACs with or without Saxagliptin and SDF-1α. Stimulation of angiogenesis by circulating cells from T2D patients treated with Saxagliptin or other non-incretinergic drugs was assessed in vivo using animal models. Results Soluble DPP-4 activity was predominant over cellular activity and was successfully inhibited by Saxagliptin. At baseline, T2D compared to healthy PACs contained less acLDL+Lectin+ cells, and showed altered expression of genes related to adhesion and cell cycle regulation. This was reflected by impaired adhesion and clonogenesis/proliferative response of T2D PACs. Saxagliptin + SDF-1α improved adhesion and tube sustaining capacity of PACs from T2D patients. CD14+ PACs were more responsive to Saxagliptin than CD14- PACs. While Saxagliptin modestly reduced angiogenesis by mature endothelial cells, circulating PACs-progeny cells from T2D patients on Saxagliptin treatment displayed higher growth factor-inducible in vivo angiogenetic activity, compared to cells from T2D patients on non-incretinergic regimen. Conclusions Saxagliptin reverses PACs dysfunction associated with T2D in vitro and improves inducible angiogenesis by circulating cells in vivo. These data add knowledge to the potential pleiotropic cardiovascular effects of DPP-4 inhibition. PMID:24886621

Saxagliptin Attenuates Albuminuria by Inhibiting Podocyte Epithelial- to-Mesenchymal Transition via SDF-1α in Diabetic Nephropathy.

PubMed

Chang, Yun-Peng; Sun, Bei; Han, Zhe; Han, Fei; Hu, Shao-Lan; Li, Xiao-Yu; Xue, Mei; Yang, Yang; Chen, Li; Li, Chun-Jun; Chen, Li-Ming

2017-01-01

The dipeptidyl peptidase-4 (DPP-4) inhibitor saxagliptin has been found to reduce progressive albuminuria, but the exact mechanism of inhibition is unclear. Podocyte epithelial-to-mesenchymal transition (EMT) has emerged as a potential pathway leading to proteinuria in diabetic nephropathy (DN). Stromal cell-derived factor-1α (SDF-1α), one of the substrates of DPP-4, can activate the protein kinase A pathway and subsequently inhibit its downstream effector, transforming growth factor-β1 (TGF-β1), which induces podocyte EMT. Thus, this study was designed to test the hypothesis that saxagliptin reduces progressive albuminuria by preventing podocyte EMT through inhibition of SDF-1α cleavage in DN. The results of a series of assays, including ELISA, western blotting, and immunochemistry/immunofluorescence, showed that saxagliptin treatment obviously ameliorated urinary microalbumin excretion and renal histological changes in high-fat diet/streptozotocin-induced diabetic rats. Furthermore, saxagliptin-treated diabetic rats presented with suppression of DPP-4 activity/protein expression accompanied by restoration of SDF-1α levels, which subsequently hindered NOX2 expression and podocyte EMT. In vitro , we consistently observed that saxagliptin significantly inhibited increased DPP-4 activity/expression, oxidative stress and podocyte EMT. Application of an SDF-1α receptor inhibitor (AMD3100) to cultured podocytes further confirmed the essential role of SDF-1α in podocyte EMT inhibition. In sum, we demonstrated for the first time that saxagliptin treatment plays an essential role in ameliorating progressive DN by preventing podocyte EMT through a SDF-1α-related pathway, suggesting that saxagliptin could offer renoprotection and that SDF-1α might be a potential therapeutic target for DN.

Saxagliptin Attenuates Albuminuria by Inhibiting Podocyte Epithelial- to-Mesenchymal Transition via SDF-1α in Diabetic Nephropathy

PubMed Central

Chang, Yun-peng; Sun, Bei; Han, Zhe; Han, Fei; Hu, Shao-lan; Li, Xiao-yu; Xue, Mei; Yang, Yang; Chen, Li; Li, Chun-jun; Chen, Li-ming

2017-01-01

The dipeptidyl peptidase-4 (DPP-4) inhibitor saxagliptin has been found to reduce progressive albuminuria, but the exact mechanism of inhibition is unclear. Podocyte epithelial-to-mesenchymal transition (EMT) has emerged as a potential pathway leading to proteinuria in diabetic nephropathy (DN). Stromal cell–derived factor-1α (SDF-1α), one of the substrates of DPP-4, can activate the protein kinase A pathway and subsequently inhibit its downstream effector, transforming growth factor-β1 (TGF-β1), which induces podocyte EMT. Thus, this study was designed to test the hypothesis that saxagliptin reduces progressive albuminuria by preventing podocyte EMT through inhibition of SDF-1α cleavage in DN. The results of a series of assays, including ELISA, western blotting, and immunochemistry/immunofluorescence, showed that saxagliptin treatment obviously ameliorated urinary microalbumin excretion and renal histological changes in high-fat diet/streptozotocin-induced diabetic rats. Furthermore, saxagliptin-treated diabetic rats presented with suppression of DPP-4 activity/protein expression accompanied by restoration of SDF-1α levels, which subsequently hindered NOX2 expression and podocyte EMT. In vitro, we consistently observed that saxagliptin significantly inhibited increased DPP-4 activity/expression, oxidative stress and podocyte EMT. Application of an SDF-1α receptor inhibitor (AMD3100) to cultured podocytes further confirmed the essential role of SDF-1α in podocyte EMT inhibition. In sum, we demonstrated for the first time that saxagliptin treatment plays an essential role in ameliorating progressive DN by preventing podocyte EMT through a SDF-1α-related pathway, suggesting that saxagliptin could offer renoprotection and that SDF-1α might be a potential therapeutic target for DN. PMID:29163166

The dipeptidyl peptidase-4 inhibitor saxagliptin improves function of circulating pro-angiogenic cells from type 2 diabetic patients.

PubMed

Poncina, Nicol; Albiero, Mattia; Menegazzo, Lisa; Cappellari, Roberta; Avogaro, Angelo; Fadini, Gian Paolo

2014-05-14

Type 2 diabetes (T2D) is associated with reduction and dysfunction of circulating pro-angiogenic cells (PACs). DPP-4 inhibitors, a class of oral agents for T2D, might possess pleiotropic vasculoprotective activities. Herein, we tested whether DPP-4 inhibition with Saxagliptin affects the function of circulating PACs from T2D and healthy subjects. PACs were isolated from T2D (n = 20) and healthy (n = 20) subjects. Gene expression, clonogenesis, proliferation, adhesion, migration and tubulisation were assessed in vitro by incubating PACs with or without Saxagliptin and SDF-1α. Stimulation of angiogenesis by circulating cells from T2D patients treated with Saxagliptin or other non-incretinergic drugs was assessed in vivo using animal models. Soluble DPP-4 activity was predominant over cellular activity and was successfully inhibited by Saxagliptin. At baseline, T2D compared to healthy PACs contained less acLDL(+)Lectin(+) cells, and showed altered expression of genes related to adhesion and cell cycle regulation. This was reflected by impaired adhesion and clonogenesis/proliferative response of T2D PACs. Saxagliptin + SDF-1α improved adhesion and tube sustaining capacity of PACs from T2D patients. CD14+ PACs were more responsive to Saxagliptin than CD14- PACs. While Saxagliptin modestly reduced angiogenesis by mature endothelial cells, circulating PACs-progeny cells from T2D patients on Saxagliptin treatment displayed higher growth factor-inducible in vivo angiogenetic activity, compared to cells from T2D patients on non-incretinergic regimen. Saxagliptin reverses PACs dysfunction associated with T2D in vitro and improves inducible angiogenesis by circulating cells in vivo. These data add knowledge to the potential pleiotropic cardiovascular effects of DPP-4 inhibition.

Design and synthesis of aminocoumarin derivatives as DPP-IV inhibitors and anticancer agents.

PubMed

Soni, Rina; Soman, Shubhangi S

2018-09-01

DPP-IV "a moonlighting protein" has immerged as promising pathway to control Type 2 diabetes as well as found to play key role in earlier stages of cancer. Here we have reported design, synthesis and applications of aminocoumarin derivatives as DPP-IV inhibitors. Compounds have been synthesized and studied for their DPP-IV inhibition activity. Three compounds have shown moderate inhibition at 100 µM concentration. All compounds were also screened for their anticancer activity against A549 (Lung cancer cell line), MCF-7 (Breast cancer cell line) using MTT assay. One of the compounds has shown very good anticancer activity with IC 50 value 24 ± 0.1 nM against A549 cell line. Copyright © 2018 Elsevier Inc. All rights reserved.

Protective Effects of Vildagliptin against Pioglitazone-Induced Bone Loss in Type 2 Diabetic Rats

PubMed Central

Kwak, Kyung Min; Kim, Ju-Young; Yu, Seung Hee; Lee, Sihoon; Kim, Yeun Sun; Park, Ie Byung; Kim, Kwang-Won; Lee, Kiyoung

2016-01-01

Long-term use of thiazolidinediones (TZDs) is associated with bone loss and an increased risk of fracture in patients with type 2 diabetes (T2DM). Incretin-based drugs (glucagon-like peptide-1 (GLP-1) agonists and dipeptidylpeptidase-4 (DPP-4) inhibitors) have several benefits in many systems in addition to glycemic control. In a previous study, we reported that exendin-4 might increase bone mineral density (BMD) by decreasing the expression of SOST/sclerostin in osteocytes in a T2DM animal model. In this study, we investigated the effects of a DPP-4 inhibitor on TZD-induced bone loss in a T2DM animal model. We randomly divided 12-week-old male Zucker Diabetic Fatty (ZDF) rats into four groups; control, vildagliptin, pioglitazone, and vildagliptin and pioglitazone combination. Animals in each group received the respective treatments for 5 weeks. We performed an intraperitoneal glucose tolerance test (IPGTT) before and after treatment. BMD and the trabecular micro-architecture were measured by DEXA and micro CT, respectively, at the end of the treatment. The circulating levels of active GLP-1, bone turnover markers, and sclerostin were assayed. Vildagliptin treatment significantly increased BMD and trabecular bone volume. The combination therapy restored BMD, trabecular bone volume, and trabecular bone thickness that were decreased by pioglitazone. The levels of the bone formation marker, osteocalcin, decreased and that of the bone resorption marker, tartrate-resistant acid phosphatase (TRAP) 5b increased in the pioglitazone group. These biomarkers were ameliorated and the pioglitazone-induced increase in sclerostin level was lowered to control values by the addition of vildagliptin. In conclusion, our results indicate that orally administered vildagliptin demonstrated a protective effect on pioglitazone-induced bone loss in a type 2 diabetic rat model. PMID:27997588

Protective Effects of Vildagliptin against Pioglitazone-Induced Bone Loss in Type 2 Diabetic Rats.

PubMed

Eom, Young Sil; Gwon, A-Ryeong; Kwak, Kyung Min; Kim, Ju-Young; Yu, Seung Hee; Lee, Sihoon; Kim, Yeun Sun; Park, Ie Byung; Kim, Kwang-Won; Lee, Kiyoung; Kim, Byung-Joon

2016-01-01

Long-term use of thiazolidinediones (TZDs) is associated with bone loss and an increased risk of fracture in patients with type 2 diabetes (T2DM). Incretin-based drugs (glucagon-like peptide-1 (GLP-1) agonists and dipeptidylpeptidase-4 (DPP-4) inhibitors) have several benefits in many systems in addition to glycemic control. In a previous study, we reported that exendin-4 might increase bone mineral density (BMD) by decreasing the expression of SOST/sclerostin in osteocytes in a T2DM animal model. In this study, we investigated the effects of a DPP-4 inhibitor on TZD-induced bone loss in a T2DM animal model. We randomly divided 12-week-old male Zucker Diabetic Fatty (ZDF) rats into four groups; control, vildagliptin, pioglitazone, and vildagliptin and pioglitazone combination. Animals in each group received the respective treatments for 5 weeks. We performed an intraperitoneal glucose tolerance test (IPGTT) before and after treatment. BMD and the trabecular micro-architecture were measured by DEXA and micro CT, respectively, at the end of the treatment. The circulating levels of active GLP-1, bone turnover markers, and sclerostin were assayed. Vildagliptin treatment significantly increased BMD and trabecular bone volume. The combination therapy restored BMD, trabecular bone volume, and trabecular bone thickness that were decreased by pioglitazone. The levels of the bone formation marker, osteocalcin, decreased and that of the bone resorption marker, tartrate-resistant acid phosphatase (TRAP) 5b increased in the pioglitazone group. These biomarkers were ameliorated and the pioglitazone-induced increase in sclerostin level was lowered to control values by the addition of vildagliptin. In conclusion, our results indicate that orally administered vildagliptin demonstrated a protective effect on pioglitazone-induced bone loss in a type 2 diabetic rat model.

Anagliptin, A Dipeptidyl Peptidase-4 Inhibitor Ameliorates Arterial Stiffness in Association with Reduction of Remnant-Like Particle Cholesterol and Alanine Transaminase Levels in Type 2 Diabetic Patients.

PubMed

Tahara, Nobuhiro; Yamagishi, Sho-Ichi; Bekki, Munehisa; Kodama, Norihiro; Nakamura, Tomohisa; Sugiyama, Yoichi; Oshige, Tamami; Kumashiro, Yuki; Honda, Akihiro; Tahara, Atsuko; Igata, Sachiyo; Fukumoto, Yoshihiro

2016-01-01

Inhibition of dipeptidyl peptidase-4 (DPP-4) has been proposed as a therapeutic target for type 2 diabetes (T2DM). Arterial stiffness, a predictor of future cardiovascular events and all-cause mortality, is augmented in these patients. However, effects of DPP-4 inhibitors on arterial stiffness remain unknown. In this study, we compared effects of anagliptin, an inhibitor of DPP-4 on arterial stiffness evaluated by cardio-ankle vascular index (CAVI) with those of an equipotent glucose-lowering agent, glimepiride in patients with T2DM. The study involved 50 consecutive outpatients (33 males and 17 females; mean age of 72.5±9.5 years) who visited our hospitals for a risk-screening test or treatment for T2DM. They underwent complete history and physical examination, and determination of blood chemistry and anthropometric variables, and then were randomized to receive either anagliptin (n=26) or glimepiride (n=24) for 6 months. After 6-months treatment, fasting plasma glucose and HbA1c values were comparably reduced in both groups. Anagliptin, but not glimepiride treatment significantly decreased low-density lipoprotein cholesterol, malondialdehyde-modified LDL, remnant-like particle (RLP) cholesterol, CAVI, alanine transaminase (ALT), γ-glutamyl transferase and visceral fat volume. In multiple regression analysis, absolute changes from baseline of RLP cholesterol and ALT after anagliptin treatment for 6 months (ΔRLP cholesterol and ΔALT) were independently correlated with ΔCAVI (R2=0.445). The present study suggests that anagliptin may exert a beneficial effect on arterial stiffness in patients with T2DM, which is independent of its blood glucose-lowering property. Anagliptin may ameliorate arterial stiffness partly via reduction of RLP cholesterol and improvement of liver function.

Unravelling the immunological roles of dipeptidyl peptidase 4 (DPP4) activity and/or structure homologue (DASH) proteins

PubMed Central

Klemann, C.; Stephan, M.

2016-01-01

Summary Dipeptidyl peptidase (DPP) 4 (CD26, DPP4) is a multi‐functional protein involved in T cell activation by co‐stimulation via its association with adenosine deaminase (ADA), caveolin‐1, CARMA‐1, CD45, mannose‐6‐phosphate/insulin growth factor‐II receptor (M6P/IGFII‐R) and C‐X‐C motif receptor 4 (CXC‐R4). The proline‐specific dipeptidyl peptidase also modulates the bioactivity of several chemokines. However, a number of enzymes displaying either DPP4‐like activities or representing structural homologues have been discovered in the past two decades and are referred to as DPP4 activity and/or structure homologue (DASH) proteins. Apart from DPP4, DASH proteins include fibroblast activation protein alpha (FAP), DPP8, DPP9, DPP4‐like protein 1 (DPL1, DPP6, DPPX L, DPPX S), DPP4‐like protein 2 (DPL2, DPP10) from the DPP4‐gene family S9b and structurally unrelated enzyme DPP2, displaying DPP4‐like activity. In contrast, DPP6 and DPP10 lack enzymatic DPP4‐like activity. These DASH proteins play important roles in the immune system involving quiescence (DPP2), proliferation (DPP8/DPP9), antigen‐presenting (DPP9), co‐stimulation (DPP4), T cell activation (DPP4), signal transduction (DPP4, DPP8 and DPP9), differentiation (DPP4, DPP8) and tissue remodelling (DPP4, FAP). Thus, they are involved in many pathophysiological processes and have therefore been proposed for potential biomarkers or even drug targets in various cancers (DPP4 and FAP) and inflammatory diseases (DPP4, DPP8/DPP9). However, they also pose the challenge of drug selectivity concerning other DASH members for better efficacy and/or avoidance of unwanted side effects. Therefore, this review unravels the complex roles of DASH proteins in immunology. PMID:26671446

Glucose-lowering agents for treating pre-existing and new-onset diabetes in kidney transplant recipients.

PubMed

Lo, Clement; Jun, Min; Badve, Sunil V; Pilmore, Helen; White, Sarah L; Hawley, Carmel; Cass, Alan; Perkovic, Vlado; Zoungas, Sophia

2017-02-27

Kidney transplantation is the preferred form of kidney replacement therapy for patients with end-stage kidney disease (ESKD) and is often complicated by worsening or new-onset diabetes. Management of hyperglycaemia is important to reduce post-transplant and diabetes-related complications. The safety and efficacy of glucose-lowering agents after kidney transplantation is largely unknown. To evaluate the efficacy and safety of pharmacological interventions for lowering glucose levels in patients who have undergone kidney transplantation and have diabetes. We searched the Cochrane Kidney and Transplant Specialised Register to 15 April 2016 through contact with the Information Specialist using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE, and EMBASE; handsearching conference proceedings; and searching the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. All randomised controlled trials (RCTs), quasi-RCTs and cross-over studies examining head-to-head comparisons of active regimens of glucose-lowering therapy or active regimen compared with placebo/standard care in patients who have received a kidney transplant and have diabetes were eligible for inclusion. Two authors independently assessed study eligibility and quality and performed data extraction. Continuous outcomes were expressed as post-treatment mean differences (MD) or standardised mean difference (SMD). Adverse events were expressed as post-treatment absolute risk differences (RD). Dichotomous clinical outcomes were presented as risk ratios (RR) with 95% confidence intervals (CI). We included seven studies that involved a total of 399 kidney transplant recipients. All included studies had observed heterogeneity in the patient population, interventions and measured outcomes or missing data (which was unavailable despite correspondence with authors). Many studies had incompletely reported methodology preventing meta-analysis and leading to low confidence in treatment estimates.Three studies with 241 kidney transplant recipients examined the use of more intensive compared to less intensive insulin therapy in kidney transplant recipients with pre-existing type 1 or 2 diabetes. Evidence for the effects of more intensive compared to less intensive insulin therapy on transplant graft survival, HbA1c, fasting blood glucose, all cause mortality and adverse effects including hypoglycaemia was of very low quality. More intensive versus less intensive insulin therapy resulted in no difference in transplant or graft survival over three to five years in one study while another study showed that more intensive versus less intensive insulin therapy resulted in more rejection events over the three year follow-up (11 events in total; 9 in the more intensive group, P = 0.01). One study showed that more intensive insulin therapy resulted in a lower mean HbA1c (10 ± 0.8% versus 13 ± 0.9%) and lower fasting blood glucose (7.22 ± 0.5 mmol/L versus 13.44 ± 1.22 mmol/L) at 13 months compared with standard insulin therapy. Another study showed no difference between more intensive compared to less intensive insulin therapy on all-cause mortality over a five year follow-up period. All studies showed either an increased frequency of hypoglycaemia or severe hypoglycaemia episodes.Three studies with a total of 115 transplant recipients examined the use of DPP4 inhibitors for new-onset diabetes after transplantation. Evidence for the treatment effect of DPP4 inhibitors on transplant or graft survival, HbA1c and fasting blood glucose levels, all cause mortality, and adverse events including hypoglycaemia was of low quality. One study comparing vildagliptin to placebo and another comparing sitagliptin to placebo showed no difference in transplant or graft survival over two to four months of follow-up. One study comparing vildagliptin to placebo showed no significant change in estimated glomerular filtration rate from baseline (1.9 ± 10.3 mL/min/1.73 m 2 , P = 0.48 and 2.1 ± 6.1 mL/min/1.73 m 2 , P = 0.22) and no deaths, in either treatment group over three months of follow-up. One study comparing vildagliptin to placebo showed a lower HbA1c level (mean ± SD) (6.3 ± 0.5% versus versus 6.7 ± 0.6%, P = 0.03) and trend towards a greater lowering of fasting blood glucose (-0.91 ± -0.92 mmol/L versus vs -0.19 ± 1.16 mmol/L, P = 0.08) with vildagliptin. One study comparing sitagliptin to insulin glargine showed an equivalent lowering of HbA1c (-0.6 ± 0.5% versus -0.6 ± 0.6%, P = NS) and fasting blood glucose (4.92 ± 1.42 versus 4.76 ± 1.09 mmol/L, P = NS) with sitagliptin. For the outcome of hypoglycaemia, one study comparing vildagliptin to placebo reported no episodes of hypoglycaemia, one study comparing sitagliptin to insulin glargine reported fewer episodes of hypoglycaemia with sitagliptin (3/28 patients; 10.7% versus 5/28; 17.9%) and one cross-over study of sitagliptin and placebo reported two episodes of asymptomatic moderate hypoglycaemia (2 to 3.9 mmol/L) when sitagliptin was administered with glipizide. All three studies reported no drug interactions between DPP4 inhibitors and the immunosuppressive agents taken.Evidence for the treatment effect of pioglitazone for treating pre-existing diabetes was of low quality. One study with 62 transplant recipients compared the use of pioglitazone with insulin to insulin alone for treating pre-existing diabetes. Pioglitazone resulted in a lower HbA1c level (mean ± SD) (-1.21 ± 1.2 versus 0.39 ± 1%, P < 0.001) but had no effects on fasting blood glucose (6.58 ± 2.71 versus 7.28 ± 2.78 mmol/L, P = 0.14 ), and change in creatinine (3.54 ± 15.03 versus 10.61 ± 18.56 mmol/L, P = 0.53) and minimal adverse effects (no episodes of hypoglycaemia, three dropped out due to mild to moderate lower extremity oedema, cyclosporin levels were not affected). Evidence concerning the efficacy and safety of glucose-lowering agents for treating pre-existing and new-onset diabetes in kidney transplant recipients is limited. Existing studies examine more intensive versus less intensive insulin therapy, and the use of DPP4 inhibitors and pioglitazone. The safety and efficacy of more intensive compared to less intensive insulin therapy is very uncertain and the safety and efficacy of DPP4 inhibitors and pioglitazone is uncertain, due to data being limited and of poor quality. Additional RCTs are required to clarify the safety and efficacy of current glucose-lowering agents for kidney transplant recipients with diabetes.

Sodium-glucose co-transporter-2 inhibitors, the latest residents on the block: Impact on glycaemic control at a general practice level in England.

PubMed

Heald, Adrian H; Fryer, Anthony A; Anderson, Simon G; Livingston, Mark; Lunt, Mark; Davies, Mark; Moreno, Gabriela Y C; Gadsby, Roger; Young, Robert J; Stedman, Mike

2018-03-08

To determine, using published general practice-level data, how differences in Type 2 diabetes mellitus (T2DM) prescribing patterns relate to glycaemic target achievement levels. Multiple linear regression modelling was used to link practice characteristics and defined daily dose (DDD) of different classes of medication in 2015/2016 and changes between that year and the year 2014/2015 in medication to proportion of patients achieving target glycaemic control (glycated haemoglobin A1c [HbA1c] ≤58 mmol/mol [7.5%]) and proportion of patients at high glycaemic risk (HbA1c >86 mmol/mol [10.0%]) for practices in the National Diabetes Audit with >100 people with T2DM on their register. Overall, HbA1c outcomes were not different between the years studied. Although, in percentage terms, most practices increased their use of sodium-glucose co-transporter-2 (SGLT2) inhibitors (96%), dipeptidyl peptidase-4 (DPP-4) inhibitors (76%) and glucagon-like peptide 1 (GLP-1) analogues (53%), there was wide variation in the use of older and newer therapies. For example, 12% of practices used >200% of the national average for some newer agents. In cross-sectional analysis, greater prescribing of metformin and analogue insulin were associated with a higher proportion of patients achieving HbA1c ≤58 mmol/mol; the use of SGLT2 inhibitors and metformin was associated with a reduced proportion of patients with HbA1c >86 mol/mol; otherwise associations for sulphonylureas, GLP-1 analogues, SGLT2 inhibitors and DPP-4 inhibitors were neutral or negative. In year-on-year analysis there was ongoing deterioration in glycaemic control, which was offset to some extent by increased use of SGLT2 inhibitors and GLP-1 analogues, which were associated with a greater proportion of patients achieving HbA1c levels ≤58 mmol/mol and a smaller proportion of patients with HbA1c levels >86 mmol/mol. SGLT2 inhibitor prescribing was associated with significantly greater improvements than those found for GLP-1 analogues. Greater use of newer agents was associated with improvement in glycaemic outcomes but was not sufficient to compensate for the prevailing decline. This may reflect wide variability in the prescribing of newer agents. We found that SGLT inhibitors may be superior to other oral agents in relation to HbA1c outcome. Serious consideration should be given to their use. © 2018 John Wiley & Sons Ltd.

Budget Impact of Introducing Linagliptin into Bosnia and Herzegovina Health Insurance Drug Reimbursement List in 2016-2018.

PubMed

Catic, Tarik; Lekic, Lana; Zah, Vlad; Tabakovic, Vedad

2017-09-01

Diabetes is reaching epidemiological scales worldwide. Beside health implications diabetes bears significant financial impact on health systems. Different treatment options aiming to prevent diabetes complications are available. Dipeptidyl-peptidase-IV (DPP-4) inhibitors like linagliptin are usually add-on therapy to metformin in order to achieve glycemic control. Expenditure for oral antidiabetic medicines in Bosnia and Herzegovina (B&H) is low accounting for only 2.53% of the total drug market expenditure. Linagliptin is not reimbursed in B&H mainly due to it's perception of high cost medication. To assess budget impact (BI) of introducing linagliptin into health insurance reimbursement list in B&H through development of the budget impact model (BIM). Budget impact model was developed using Microsoft Excel 2010 based on current legislation and practice in B&H. Local epidemiology data and data on drug consumption from government reports in 2014 were used. Two scenarios with three-year time horizon have been developed: 1) without and 2) with linagliptin reimbursed and compared. Inclusion of linagliptin into reimbursement list in Canton Sarajevo and Canton Tuzla would have positive budget impact on national level of B&H resulting in total savings of 18,194€, 235,570€ and 699,472€, in 2016, 2017 and 2018, respectively. Introduction of linagliptin into reimbursement list would decrease total costs for DPP-4 inhibitors and is favorable for positive decision on reimbursement in B&H. Applying BIM in decision making would assure better allocation and planning of resources at any region or administrative level in B&H.

Comparative Analysis of Binding Kinetics and Thermodynamics of Dipeptidyl Peptidase-4 Inhibitors and Their Relationship to Structure.

PubMed

Schnapp, Gisela; Klein, Thomas; Hoevels, Yvette; Bakker, Remko A; Nar, Herbert

2016-08-25

The binding kinetics and thermodynamics of dipeptidyl peptidase (DPP)-4 inhibitors (gliptins) were investigated using surface plasmon resonance and isothermal titration calorimetry. Binding of gliptins to DPP-4 is a rapid electrostatically driven process. Off-rates were generally slow partly because of reversible covalent bond formation by some gliptins, and partly because of strong and extensive interactions. Binding of all gliptins is enthalpy-dominated due to strong ionic interactions and strong solvent-shielded hydrogen bonds. Using a congeneric series of molecules which represented the intermediates in the lead optimization program of linagliptin, the onset of slow binding kinetics and development of the thermodynamic repertoire were analyzed in the context of incremental changes of the chemical structures. All compounds rapidly associated, and therefore the optimization of affinity and residence time is highly correlated. The major contributor to the increasing free energy of binding was a strong increase of binding enthalpy, whereas entropic contributions remained low and constant despite significant addition of lipophilicity.

Diabetes and cardiovascular risk: are dipeptidyl peptidase-4 inhibitors beneficial?

PubMed

Howard, Patricia A

2014-09-01

Cardiovascular (CV) disease is a major cause of morbidity and mortality in patients with diabetes. Whereas the link between glycemic control and reducing microvascular disease is firmly established, the evidence for macrovascular risk reduction remains unclear. Despite a host of available drugs for lowering serum glucose, none to date have been shown to substantially reduce CV risk and some have been associated with adverse effects. Recent trials have examined the CV effects of the dipeptidyl peptidase 4 (DPP-4) inhibitors or "gliptins."

Postauthorization safety study of the DPP-4 inhibitor saxagliptin: a large-scale multinational family of cohort studies of five outcomes.

PubMed

Lo Re, Vincent; Carbonari, Dena M; Saine, M Elle; Newcomb, Craig W; Roy, Jason A; Liu, Qing; Wu, Qufei; Cardillo, Serena; Haynes, Kevin; Kimmel, Stephen E; Reese, Peter P; Margolis, David J; Apter, Andrea J; Reddy, K Rajender; Hennessy, Sean; Bhullar, Harshvinder; Gallagher, Arlene M; Esposito, Daina B; Strom, Brian L

2017-01-01

To evaluate the risk of serious adverse events among patients with type 2 diabetes mellitus initiating saxagliptin compared with oral antidiabetic drugs (OADs) in classes other than dipeptidyl peptidase-4 (DPP-4) inhibitors. Cohort studies using 2009-2014 data from two UK medical record data sources (Clinical Practice Research Datalink, The Health Improvement Network) and two USA claims-based data sources (HealthCore Integrated Research Database, Medicare). All eligible adult patients newly prescribed saxagliptin (n=110 740) and random samples of up to 10 matched initiators of non-DPP-4 inhibitor OADs within each data source were selected (n=913 384). Outcomes were hospitalized major adverse cardiovascular events (MACE), acute kidney injury (AKI), acute liver failure (ALF), infections, and severe hypersensitivity events, evaluated using diagnostic coding algorithms and medical records. Cox regression was used to determine HRs with 95% CIs for each outcome. Meta-analyses across data sources were performed for each outcome as feasible. There were no increased incidence rates or risk of MACE, AKI, ALF, infection, or severe hypersensitivity reactions among saxagliptin initiators compared with other OAD initiators within any data source. Meta-analyses demonstrated a reduced risk of hospitalization/death from MACE (HR 0.91, 95% CI 0.85 to 0.97) and no increased risk of hospitalization for infection (HR 0.97, 95% CI 0.93 to 1.02) or AKI (HR 0.99, 95% CI 0.88 to 1.11) associated with saxagliptin initiation. ALF and hypersensitivity events were too rare to permit meta-analysis. Saxagliptin initiation was not associated with increased risk of MACE, infection, AKI, ALF, or severe hypersensitivity reactions in clinical practice settings. NCT01086280, NCT01086293, NCT01086319, NCT01086306, and NCT01377935; Results.

Sitagliptin attenuates sympathetic innervation via modulating reactive oxygen species and interstitial adenosine in infarcted rat hearts.

PubMed

Lee, Tsung-Ming; Chen, Wei-Ting; Yang, Chen-Chia; Lin, Shinn-Zong; Chang, Nen-Chung

2015-02-01

We investigated whether sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, attenuates arrhythmias through inhibiting nerve growth factor (NGF) expression in post-infarcted normoglycemic rats, focusing on adenosine and reactive oxygen species production. DPP-4 bound adenosine deaminase has been shown to catalyse extracellular adenosine to inosine. DPP-4 inhibitors increased adenosine levels by inhibiting the complex formation. Normoglycemic male Wistar rats were subjected to coronary ligation and then randomized to either saline or sitagliptin in in vivo and ex vivo studies. Post-infarction was associated with increased oxidative stress, as measured by myocardial superoxide, nitrotyrosine and dihydroethidium fluorescent staining. Measurement of myocardial norepinephrine levels revealed a significant elevation in vehicle-treated infarcted rats compared with sham. Compared with vehicle, infarcted rats treated with sitagliptin significantly increased interstitial adenosine levels and attenuated oxidative stress. Sympathetic hyperinnervation was blunted after administering sitagliptin, as assessed by immunofluorescent analysis and western blotting and real-time quantitative RT-PCR of NGF. Arrhythmic scores in the sitagliptin-treated infarcted rats were significantly lower than those in vehicle. Ex vivo studies showed a similar effect of erythro-9-(2-hydroxy-3-nonyl) adenine (an adenosine deaminase inhibitor) to sitagliptin on attenuated levels of superoxide and NGF. Furthermore, the beneficial effects of sitagliptin on superoxide anion production and NGF levels can be reversed by 8-cyclopentyl-1,3-dipropulxanthine (adenosine A1 receptor antagonist) and exogenous hypoxanthine. Sitagliptin protects ventricular arrhythmias by attenuating sympathetic innervation via adenosine A1 receptor and xanthine oxidase-dependent pathways, which converge through the attenuated formation of superoxide in the non-diabetic infarcted rats. © 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

CD26 modulates nociception in mice via its dipeptidyl-peptidase IV activity.

PubMed

Guieu, Regis; Fenouillet, Emmanuel; Devaux, Christiane; Fajloun, Ziad; Carrega, Louis; Sabatier, Jean-Marc; Sauze, Nicole; Marguet, Didier

2006-01-30

CD26 is a multifunctional cell surface glycoprotein expressed by T and B cells. It exhibits a dipeptidyl-peptidase activity (DPP-IV) that cleaves the penultimate proline from the N-terminus of polypeptides, thereby regulating their activity and concentration. Using CD26-/- mice resulting from targeted inactivation of the gene, we examined the consequences of a DPP-IV defect on behavioural response to nociceptive stimuli and concentration of the pain modulator peptides substance P (SP) and endomorphin 2, two DPP-IV substrates. CD26 inactivation induced a three-fold decrease in circulating endopeptidase activity while that found in brain extracts was normal, albeit very weak. CD26-/- mice had high SP concentrations in plasma (3.4+/-1 pg/ml versus 1.5+/-0.3 pg/ml, P<10(-3)) but not in brain extracts (35+/-12 pg/ml versus 32+/-9 pg/ml, P>0.05). Endomorphin-2 levels in the two groups were in the same range for plasma and brain extracts. CD26-/- mice displayed short latencies to nociceptive stimuli (hot plate test: 6.6+/-1.2 s versus 8.6+/-1.5 s, P<10(-4); tail pinch test: 3.1+/-0.6 s versus 4.2+/-0.8 s, P<10(-3)). Administration of an SP (NK1) receptor antagonist or DPP-IV to CD26-/- mice normalised latencies. DPP-IV inhibitors decreased latencies only in CD26+/+ mice. Our observations represent the first fundamental evidence showing that DPP-IV influences pain perception via modulation of the peripheral SP concentration. Our work also highlights the role of peripheral NK1 receptors in nociception.

Acylated Gly-(2-cyano)pyrrolidines as inhibitors of fibroblast activation protein (FAP) and the issue of FAP/prolyl oligopeptidase (PREP)-selectivity.

PubMed

Ryabtsova, Oxana; Jansen, Koen; Van Goethem, Sebastiaan; Joossens, Jurgen; Cheng, Jonathan D; Lambeir, Anne-Marie; De Meester, Ingrid; Augustyns, Koen; Van der Veken, Pieter

2012-05-15

A series of N-acylated glycyl-(2-cyano)pyrrolidines were synthesized with the aim of generating structure-activity relationship (SAR) data for this class of compounds as inhibitors of fibroblast activation protein (FAP). Specifically, the influence of (1) the choice of the N-acyl group and (2) structural modification of the 2-cyanopyrrolidine residue were investigated. The inhibitors displayed inhibitory potency in the micromolar to nanomolar range and showed good to excellent selectivity with respect to the proline selective dipeptidyl peptidases (DPPs) DPP IV, DPP9 and DPP II. Additionally, selectivity for FAP with respect to prolyl oligopeptidase (PREP) is reported. Not unexpectedly, the latter data suggest significant overlap in the pharmacophoric features that define FAP or PREP-inhibitory activity and underscore the importance of systematically evaluating the FAP/PREP-selectivity index for inhibitors of either of these two enzymes. Finally, this study forwards several compounds that can serve as leads or prototypic structures for future FAP-selective-inhibitor discovery. Copyright © 2012 Elsevier Ltd. All rights reserved.

Computational Tools and Resources for Metabolism-Related Property Predictions. 1. Overview of Publicly Available (Free and Commercial) Databases and Software

DTIC Science & Technology

2012-01-01

pathway inhibitor Smoothened GPCR Basal cell carcinoma Ivacaftor Kalydeco™ Vertex 203188 31 January 2012 CFTR potentiator CFTR chloride channel ...inhibitor Platelet P2Y 12 ADP-receptor Acute coronary syndrome Ezogabine Potiga™ GlaxoSmithKline/ Valeant 022345 10 June 2011 Potassium channel opener...KCNQ/ Kv7 Epilepsy Linagliptin Tradjenta® Boehringer Ingelheim 201280 2 May 2011 Peptidase inhibitor DPP-4 Type 2 diabetes Abiraterone Zytiga® Janssen

Sitagliptin: review of preclinical and clinical data regarding incidence of pancreatitis

PubMed Central

Engel, S S; Williams-Herman, D E; Golm, G T; Clay, R J; Machotka, S V; Kaufman, K D; Goldstein, B J

2010-01-01

Recent case reports of acute pancreatitis in patients with type 2 diabetes (T2DM) treated with incretin-based therapies have triggered interest regarding the possibility of a mechanism-based association between pancreatitis and glucagon-like peptide-1 mimetics or dipeptidyl peptidase-4 (DPP-4) inhibitors. The objective of this review was to describe the controlled preclinical and clinical trial data regarding the incidence of pancreatitis with sitagliptin, the first DPP-4 inhibitor approved for use in patients with T2DM. Tissue samples from multiple animal species treated with sitagliptin for up to 2 years at plasma exposures substantially in excess of human exposure were evaluated to determine whether any potential gross or histomorphological changes suggestive of pancreatitis occurred. Sections were prepared by routine methods, stained with haematoxylin and eosin and examined microscopically. A pooled analysis of 19 controlled clinical trials, comprising 10,246 patients with T2DM treated for up to 2 years, was performed using patient-level data from each study for the evaluation of clinical and laboratory adverse events. Adverse events were encoded using the Medical Dictionary for Regulatory Activities (MedDRA) version 12.0 system. Incidences of adverse events were adjusted for patient exposure. Tissue samples from preclinical studies in multiple animal species did not reveal any evidence of treatment-related pancreatitis. The pooled analysis of controlled clinical trials revealed similar incidence rates of pancreatitis in patients treated with sitagliptin compared with those not treated with sitagliptin (0.08 events per 100 patient-years vs. 0.10 events per 100 patient-years, respectively). Preclinical and clinical trial data with sitagliptin to date do not indicate an increased risk of pancreatitis in patients with T2DM treated with sitagliptin. PMID:20412332

Therapeutic molecules against type 2 diabetes: What we have and what are we expecting?

PubMed

Kumar, Ashwini; Bharti, Sudhanshu Kumar; Kumar, Awanish

2017-10-01

World Health Organization (WHO) has identified diabetes as one of the fastest growing non-communicable diseases with 422 million patients around the world in 2014. Diabetes, a metabolic disease, is characterized primarily by hyperglycemia which results in various macrovascular and microvascular complications like cardiovascular disease and neuropathies which can significantly deteriorate the quality of life. The body either does not manufactures enough insulin (type 1 diabetes or T1DM) or becomes insensitive to physiologically secreted insulin or both (type 2 diabetes or T2DM). The majority of the diabetic population is affected by type 2 diabetes. Currently, hyperglycemia is treated by a broad range of molecules such as biguanides, sulfonylurea, insulin, thiazolidinediones, incretin mimetics, and DPP-4 inhibitors exerting different mechanisms. However, new drug classes have indeed come in the market such as SGLT-2 inhibitors and other are in the experimental stages such as GPR 40 agonists, GSK-3 inhibitors, GK activators and GPR21 inhibitors which definitely could be anticipated as safe and effective for diabetes therapy. This article reviews the general approach to currently approved therapies for type 2 diabetes and focusing on novel approaches that could be a panacea and might be useful in the future for diabetes patients. Copyright © 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Dipeptidyl-peptidase IV inhibitory activity of peptides derived from tuna cooking juice hydrolysates.

PubMed

Huang, Shih-Li; Jao, Chia-Ling; Ho, Kit-Pan; Hsu, Kuo-Chiang

2012-05-01

The in vitro DPP-IV inhibitory activity of isolated peptides from of tuna cooking juice hydrolyzed by Protease XXIII (PR) and orientase (OR) was determined. The results showed that the peptide fractions with the molecular weight over 1,422 Da possessed the greatest DPP-IV inhibitory activity. The amino acid sequences of the three peptides isolated from PR and OR hydrolysates were identified by MALDI-TOF/TOF MS/MS, and they were Pro-Gly-Val-Gly-Gly-Pro-Leu-Gly-Pro-Ile-Gly-Pro-Cys-Tyr-Glu (1412.7 Da), Cys-Ala-Tyr-Gln-Trp-Gln-Arg-Pro-Val-Asp-Arg-Ile-Arg (1690.8 Da) and Pro-Ala-Cys-Gly-Gly-Phe-Try-Ile-Ser-Gly-Arg-Pro-Gly (1304.6 Da), while they showed the dose-dependent inhibition effect of DPP-IV with IC(50) values of 116.1, 78.0 and 96.4 μM, respectively. In vitro simulated gastrointestinal digestion retained or even improved the DPP-IV inhibitory activities of the three peptides. The results suggest that tuna cooking juice would be a good precursor of DPP-IV inhibitor, and the DPP-IV inhibitory peptides can successfully passed through the digestive tract. Copyright © 2012 Elsevier Inc. All rights reserved.

Hibiscus sabdariffa polyphenols alleviate insulin resistance and renal epithelial to mesenchymal transition: a novel action mechanism mediated by type 4 dipeptidyl peptidase.

PubMed

Peng, Chiung-Huei; Yang, Yi-Sun; Chan, Kuei-Chuan; Wang, Chau-Jong; Chen, Mu-Lin; Huang, Chien-Ning

2014-10-08

The epithelial to mesenchymal transition (EMT) is important in renal fibrosis. Ser307 phosphorylation of insulin receptor substrate-1 (IRS-1 (S307)) is a hallmark of insulin resistance. We report that polyphenol extracts of Hibiscus sabdariffa (HPE) ameliorate diabetic nephropathy and EMT. Recently it has been observed that type 4 dipeptidyl peptidase (DPP-4) inhibitor linagliptin is effective for treating type 2 diabetes and albuminuria. We investigated if DPP-4 and insulin resistance are involved in renal EMT and explored the role of HPE. In high glucose-stimulated tubular cells, HPE, like linagliptin, inhibited DPP-4 activation, thereby regulating vimentin (EMT marker) and IRS-1 (S307). IRS-1 knockdown revealed its essential role in mediating downstream EMT. In type 2 diabetic rats, pIRS-1 (S307) abundantly surrounds the tubular region, with increased vimentin in kidney. Both the expressions were reduced by HPE. In conclusion, HPE exerts effects similar to those of linagliptin, which improves insulin resistance and EMT, and could be an adjuvant to prevent diabetic nephropathy.

Direct reductive amination of aldehyde bisulfite adducts induced by 2-picoline borane: application to the synthesis of a DPP-IV inhibitor.

PubMed

Faul, Margaret; Larsen, Rob; Levinson, Adam; Tedrow, Jason; Vounatsos, Filisaty

2013-02-15

Aldehyde-bisulfite adducts dervied from unstable parent aldehydes were reductively alkylated in a direct fashion with a variety of amines. This approach features the use of 2-picoline borane as the reducing agent and a protic solvent for the reaction media and has been successfully applied to the synthesis of a DPP-IV inhibitor and a variety of other amines.

The protective effect of vildagliptin in chronic experimental cyclosporine A-induced hepatotoxicity.

PubMed

El-Sherbeeny, Nagla A; Nader, Manar A

2016-03-01

The study examined the effect of dipeptidyl peptidase-4 (DPP-4) inhibitor, vildagliptin, in cyclosporine (CsA)-induced hepatotoxicity. Rats were divided into 4 groups treated for 28 days: control (vehicle), vildagliptin (10 mg/kg, orally), CsA (20 mg/kg, s.c.), and CsA-vildagliptin group. Liver function was assessed by measuring serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyltransferase (γGT), lactate dehydrogenase (LDH), and albumin, and histopathological changes of liver were examined. Oxidative stress markers were evaluated. Assessment of nuclear factor-kappa B (NF-κB) activity in hepatic nuclear extract, serum DPP-4, and expression of Bax and Bcl2 were also done. CsA-induced hepatotoxicity was evidenced by increase in serum levels of AST, ALT, and γGT; a decrease in serum albumin; and a significant alteration in hepatic architecture. Also, significant increase in thiobarbituric acid reactive substance (TBARS) and decrease in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH) levels, increased expression Bax proteins with deceased expression of Bcl2, and increased hepatic activity of NF-κB and serum DPP-4 level were observed upon CsA treatment. Vildagliptin significantly improved all altered parameters induced by CsA administration. Vildagliptin has the potential to protect the liver against CsA-induced hepatotoxicity by reducing oxidative stress, DPP-4 activity, apoptosis, and inflammation.

Glycemic control parameters in insulin-naïve patients with uncontrolled type 2 diabetes referred to endocrinologists, and degree of implementation of the national Spanish consensus for the management of hyperglycemia.

PubMed

Azriel, Sharona; Casal, Florentino; Dalama, Belén; Varillas, Francisco; Villarroel, África; Soto, Alfonso; Barberá, Gloria

2014-12-01

To assess blood glucose in patients with uncontrolled type 2 diabetes mellitus treated with oral antidiabetic drugs in primary care at the time of referral to specialized endocrinologists, and the degree of implementation of the national consensus guidelines of the Spanish Society of Diabetes by evaluating steps one (S1), two (S2), and three (S3) of the escalating therapy. Retrospective, observational study where 81 endocrinologists evaluated patients ≥40 years of age referred from primary care between July 2012 and July 2013, treated with 1 to 2 oral antidiabetic drugs but no insulin therapy, and with glycosylated hemoglobin (HbA(1c)) levels ≥6.5%. Patients also had to have HbA(1c) levels and both fasting and postprandial plasma glucose measurements from the previous three months. A total of 285 patients (57.6% males) were assessed. Mean (SD) age was 63.1 (9.7) years, mean HbA1c was 8.5 (1.2) %, mean FPG was 171.7 (43) mg/dL, and mean postprandial plasma glucose was 206.8 (50) mg/dL. In primary care, 26.0% of patients were at S1 and 74.0% were at S2. After referral to the endocrinologist, 9.8% of patients moved onto S1, 42.8% onto S2, and 47.4% onto S3. Oral antidiabetic drugs most commonly prescribed in primary care were metformin (90.2%), DPP-4 inhibitors (34.4%), and sulfonylureas (30.5%), while drugs most commonly used in the specialized endocrinology setting were metformin (86%), insulin (56.8%), and DPP-4 inhibitors (49.8%). The most commonly followed guidelines were those of the American Diabetes Association and the consensus guidelines of the Spanish Society of Diabetes, in 77% and 45% of cases respectively. Approximately half the patients treated with oral antidiabetic drugs in primary care are prescribed insulin after referral to an endocrinology specialist. The most commonly followed guidelines in specialized care are the American Diabetes Association guidelines. Copyright © 2014 SEEN. Published by Elsevier Espana. All rights reserved.

Lower Risk of Death With SGLT2 Inhibitors in Observational Studies: Real or Bias?

PubMed

Suissa, Samy

2018-01-01

Two recent observational studies reported a remarkably lower rate of all-cause death associated with sodium-glucose cotransporter 2 inhibitor (-SGLT2i) use in all patients with type 2 diabetes and not only those at increased cardiovascular risk. The >50% lower mortality rates reported in these studies are much greater than those found in the BI 10773 (Empagliflozin) Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients (EMPA-REG OUTCOME) and CANagliflozin cardioVascular Assessment Study (CANVAS) randomized trials. We show that these observational studies are affected by time-related biases, including immortal time bias and time-lag bias, which tend to exaggerate the benefits observed with a drug. The Comparative Effectiveness of Cardiovascular Outcomes in New Users of SGLT-2 Inhibitors (CVD-REAL) study, based on 166,033 users of SGLT2i and 1,226,221 users of other glucose-lowering drugs (oGLD) identified from health care databases of six countries, was affected by immortal time bias. Indeed, the immortal time between the first oGLD prescription and the first SGLT2i prescription was omitted from the analysis, which resulted in increasing the rate of death in the oGLD group and thus producing the appearance of a lower risk of death with SGLT2i use. The Swedish study compared 10,879 SGLT2i/dipeptidyl peptidase 4 inhibitor (DPP-4i) users with 10,879 matched insulin users. Such comparisons involving second-line therapies with a third-line therapy can introduce time-lag bias, as the patients may not be at the same stage of diabetes. This bias is compounded by the fact that the users of insulin had already started their insulin before cohort entry, unlike the new users of SGLT2i. Finally, the study also introduces immortal time bias with respect to the effects of SGLT2i relative to DPP-4i. In conclusion, the >50% lower rate of death with SGLT2i in type 2 diabetes reported by two recent observational studies is likely exaggerated by immortal time and time-lag biases. It thus remains uncertain whether the benefit seen with empagliflozin in the EMPA-REG OUTCOME trial applies to all SGLT2i and to all patients with type 2 diabetes, not only those at increased cardiovascular risk. While observational studies can provide crucial real-world evidence for the effects of medications, they need to be carefully conducted to avoid such major time-related biases. © 2017 by the American Diabetes Association.

Suicide attempt by an overdose of sitagliptin, an oral hypoglycemic agent: a case report and a review of the literature.

PubMed

Furukawa, Shinya; Kumagi, Teru; Miyake, Teruki; Ueda, Teruhisa; Niiya, Tetsuji; Nishino, Keiichiro; Murakami, Shigeto; Murakami, Masato; Matsuura, Bunzo; Onji, Morikazu

2012-01-01

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a newer class of oral hypoglycemic agents for the management of diabetes that elevate the plasma concentration of active glucagon-like peptide-1 via inhibition of DPP-4. They effectively lower not only glycosylated hemoglobin levels, but also fasting and postprandial plasma glucose levels. Patients with diabetes occasionally consume an overdose of oral hypoglycemic agents in suicide attempts: the prevalence of depression is high in patients with diabetes, and depression is a strong risk factor for suicide. We encountered an 86-year-old woman with type 2 diabetes and depression, who was transferred to the emergency room 4h after ingestion of 1,700 mg of the DPP-4 inhibitor sitagliptin (1,700 mg is 17 times greater than the approved maximum dose). Upon arrival, she was fully conscious, plasma glucose was 124 mg/dL, and serum immunoreactive insulin level was 5.81 µU/mL. Thereafter, the plasma concentration of sitagliptin rose to 3,793 nM, which is 4.5 times higher than the value found under regular treatment with the maximum dose. The patient did not suffer from hypoglycemia, suggesting that a single oral overdose of sitagliptin is unlikely to cause hypoglycemia. A literature review of oral anti-diabetic agents revealed that overdose of biguanides is occasionally fatal when immediate intensive care is not provided. In summary, sitagliptin is a good treatment option for diabetic elderly patients or patients with psychiatric disorders who are suicidal and do not require insulin.

Phenotyping of congenic dipeptidyl peptidase 4 (DP4) deficient Dark Agouti (DA) rats suggests involvement of DP4 in neuro-, endocrine, and immune functions.

PubMed

Frerker, Nadine; Raber, Kerstin; Bode, Felix; Skripuletz, Thomas; Nave, Heike; Klemann, Christian; Pabst, Reinhard; Stephan, Michael; Schade, Jutta; Brabant, Georg; Wedekind, Dirk; Jacobs, Roland; Jörns, Anne; Forssmann, Ulf; Straub, Rainer H; Johannes, Sigrid; Hoffmann, Torsten; Wagner, Leona; Demuth, Hans-Ulrich; von Hörsten, Stephan

2009-01-01

Treatment of diabetes type 2 using chronic pharmacological inhibition of dipeptidyl peptidase 4 (DP4) still requires an in-depth analysis of models for chronic DP4 deficiency, because adverse reactions induced by some DP4 inhibitors have been described. In the present study, a novel congenic rat model of DP4 deficiency on a "DP4-high" DA rat genetic background was generated (DA.F344-Dpp4(m)/ SvH rats) and comprehensively phenotyped. Similar to chronic pharmacological inhibition of DP4, DP4 deficient rats exhibited a phenotype involving reduced diet-induced body weight gain and improved glucose tolerance associated with increased levels of glucagon-like peptide-1 (GLP-1) and bound leptin as well as decreased aminotransferases and triglycerides. Additionally, DA.F344-Dpp4(m)/SvH rats showed anxiolytic-like and reduced stress-like responses, a phenomenon presently not targeted by DP4 inhibitors. However, several immune alterations, such as differential leukocyte subset composition at baseline, blunted natural killer cell and T-cell functions, and altered cytokine levels were observed. While this animal model confirms a critical role of DP4 in GLP-1-dependent glucose regulation, genetically induced chronic DP4 deficiency apparently also affects stress-regulatory and immuneregulatory systems, indicating that the use of chronic DP4 inhibitors might have the potential to interfere with central nervous system and immune functions in vivo.

Empagliflozin/linagliptin single-pill combination therapy for patients with type 2 diabetes mellitus.

PubMed

Jain, Rajeev Kumar

2017-04-01

Type 2 diabetes mellitus (T2DM) is typically progressive, with sequential addition of therapies often needed to address increasing hyperglycemia over the disease course. Using treatments in combination may be preferred to sequential addition, as a means of providing a more rapid clinical response and potentially avoiding clinical inertia. In such cases, a single-pill combination can help to reduce pill burden. Although various single-pill combinations of oral glucose-lowering agents are available, empagliflozin/linagliptin was the first approved combination of a sodium glucose co-transporter 2 (SGLT2) inhibitor with a dipeptidyl peptidase 4 (DPP-4) inhibitor in the United States. Areas covered: Two publications of the clinical trial investigating the efficacy and safety of single-pill combinations of empagliflozin/linagliptin in treatment-naive or metformin-treated patients with T2DM (NCT01422876) are reviewed, and their potential impact on clinical practice is discussed. Expert opinion: The study discussed provides evidence for the efficacy and safety of empagliflozin/linagliptin single pills. Addition of an empagliflozin/linagliptin single pill may be considered in patients with inadequate glycemic control on metformin, or as an alternative to first-line treatment with empagliflozin or linagliptin when metformin is not suitable, particularly in patients with very poor glycemic control, or those who need to achieve target more quickly.

DPP IV inhibitor treatment attenuates bone loss and improves mechanical bone strength in male diabetic rats.

PubMed

Glorie, Lorenzo; Behets, Geert J; Baerts, Lesley; De Meester, Ingrid; D'Haese, Patrick C; Verhulst, Anja

2014-09-01

Dipeptidyl peptidase IV (DPP IV) modulates protein activity by removing dipeptides. DPP IV inhibitors are currently used to improve glucose tolerance in type 2 diabetes patients. DPP IV substrates not only increase insulin secretion but also affect bone metabolism. In this study, the effect of DPP IV inhibitor sitagliptin on bone was evaluated in normal and streptozotocin-induced diabetic rats. This study included 64 male Wistar rats divided into four groups (n = 16): two diabetic and two control groups. One diabetic and one control group received sitagliptin through drinking water. Tibiae were scanned every 3 wk using an in vivo μCT scanner. After 6 and 12 wk, rats were euthanized for histomorphometric analysis of bone parameters. The mechanical resistance of femora to fracture was assessed using a three-point bending test, and serum levels of bone metabolic markers were measured. Efficient DPP IV inhibition was achieved in sitagliptin-treated groups. Trabecular bone loss, the decrease in trabecular number, and the increase in trabecular spacing was attenuated through sitagliptin treatment in diabetic rats, as shown by in vivo μCT. Bone histomorphometry was in line with these results. μCT analysis furthermore showed that sitagliptin prevented cortical bone growth stagnation in diabetic rats, resulting in stronger femora during three-point bending. Finally, the serum levels of the resorption marker CTX-I were significantly lower in sitagliptin-treated diabetic animals compared with untreated diabetic animals. In conclusion, sitagliptin treatment attenuates bone loss and increases bone strength in diabetic rats probably through the reduction of bone resorption and independent of glycemic management. Copyright © 2014 the American Physiological Society.

Dipeptidyl-peptidase IV (DPP-IV) inhibitor delays tolerance to anxiolytic effect of ethanol and withdrawal-induced anxiety in rats.

PubMed

Sharma, Ajaykumar N; Pise, Ashish; Sharma, Jay N; Shukla, Praveen

2015-06-01

Dipeptidyl-peptidase IV (DPP-IV) is an enzyme responsible for the metabolism of endogenous gut-derived hormone, glucagon-like peptide-1 (GLP-1). DPP-IV is known for its role in energy homeostasis and pharmacological blockade of this enzyme is a recently approved clinical strategy for the management of type II diabetes. Accumulating evidences suggest that enzyme DPP-IV can affect spectrum of central nervous system (CNS) functions. However, little is known about the role of this enzyme in ethanol-mediated neurobehavioral complications. The objective of the present study was to examine the impact of DPP-IV inhibitor, sitagliptin on the development of tolerance to anxiolytic effect of ethanol and anxiety associated with ethanol withdrawal in rats. A dose-response study revealed that sitaglitpin (20 mg/kg, p.o.) per se exhibit anxiolytic effect in the elevated plus maze (EPM) test in rats. Tolerance to anxiolytic effect of ethanol (2 g/kg, i.p.; 8 % w/v) was observed from 7(th) day of ethanol-diet (6 % v/v) consumption. In contrast, tolerance to anxiolytic effect of ethanol was delayed in rats that were treated daily with sitagliptin (20 mg/kg, p.o.) as tolerance was observed from 13(th)day since commencement of ethanol-diet consumption. Discontinuation of rats from ethanol-diet after 15-days of ethanol consumption resulted in withdrawal anxiety between 8 h and 12 h post-abstinence. However, rats on 15-day ethanol-diet with concomitant sitagliptin (20 mg/kg, p.o.) treatment exhibited delay in appearance (24 h post-withdrawal) of withdrawal anxiety. In summary, DPP-IV inhibitors may prove as an attractive research strategy against ethanol tolerance and dependence.

Randomized, Double-Blind, Phase 3 Trial of Triple Therapy With Dapagliflozin Add-on to Saxagliptin Plus Metformin in Type 2 Diabetes.

PubMed

Mathieu, Chantal; Ranetti, Aurelian Emil; Li, Danshi; Ekholm, Ella; Cook, William; Hirshberg, Boaz; Chen, Hungta; Hansen, Lars; Iqbal, Nayyar

2015-11-01

To compare the efficacy and safety of treatment with dapagliflozin versus that with placebo add-on to saxagliptin plus metformin in patients whose type 2 diabetes is inadequately controlled with saxagliptin plus metformin treatment. Patients receiving treatment with stable metformin (stratum A) (screening HbA1c level 8.0-11.5% [64-102 mmol/mol]) or stable metformin and a dipeptidyl peptidase-4 (DPP-4) inhibitor (stratum B) (HbA1c 7.5-10.5% [58-91 mmol/mol]) for ≥8 weeks received open-label saxagliptin 5 mg/day and metformin for 16 weeks (stratum A) or 8 weeks (stratum B) (saxagliptin replaced any DPP-4 inhibitor). Patients with inadequate glycemic control (HbA1c 7-10.5% [53-91 mmol/mol]) were randomized to receive placebo or dapagliflozin 10 mg/day plus saxagliptin and metformin. The primary end point was the change in HbA1c from baseline to week 24. Secondary end points included fasting plasma glucose (FPG) level, 2-h postprandial glucose (PPG) level, body weight, and proportion of patients achieving an HbA1c level of <7% (53 mmol/mol). Treatment with dapagliflozin add-on to saxagliptin plus metformin resulted in a greater mean HbA1c reduction than placebo (-0.82 vs. -0.10% [-9 vs. -1.1 mmol/mol], P < 0.0001). Significantly greater reductions in FPG level, 2-h PPG level, and body weight were observed, and more patients achieved an HbA1c level of <7% (53 mmol/mol) with treatment with dapagliflozin versus placebo. Adverse events were similar across treatment groups, with a low overall risk of hypoglycemia (∼1%). Genital infections developed in more patients with dapagliflozin treatment (5%) than with placebo (0.6%). Triple therapy with dapagliflozin add-on to saxagliptin plus metformin improves glycemic control and is well tolerated in patients whose type 2 diabetes is inadequately controlled with saxagliptin plus metformin therapy. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Prolyl oligopeptidase and dipeptidyl peptidase II/dipeptidyl peptidase IV ratio in the cerebrospinal fluid in Parkinson's disease: historical overview and future prospects.

PubMed

Nagatsu, Toshiharu

2017-06-01

Prolyl oligopeptidase (also named prolyl endopeptidase; PREP) hydrolyzes the Pro-Xaa bonds of biologically active oligopeptides on their carboxyl side. In 1987, we detected PREP activity in human cerebrospinal fluid (CSF) using highly sensitive liquid chromatography-fluorometry with succinyl-Gly-Pro-4-methyl-coumarin amide as a new synthetic substrate, and found a marked decrease in its activity in the cerebrospinal fluid (CSF) from patients with Parkinson's disease (PD) as compared with its level in control patients without neurological diseases. In 2013, Hannula et al. found co-localization of PREP with α-synuclein in the postmortem PD brain. Several recent studies also suggest that the level of PREP in the brain of PD patients may be related to dopamine (DA) cell death via promotion of α-synuclein oligomerization and that inhibitors of PREP may play a neuroprotective role in PD. Although the relationship between another family of prolyl oligopeptidase enzymes, dipeptidyl peptidase II (DPP II) and dipeptidyl peptidase IV (DPP IV), and α-synuclein in the PD brain is not yet clear, we found that the DPP II activity/DPP IV activity ratio in the CSF was significantly increased in PD patients. This review discusses the possibility of PREP as well as the DPP II/DPP IV ratio in the CSF as potential biomarkers of PD.

Budget Impact of Introducing Linagliptin into Bosnia and Herzegovina Health Insurance Drug Reimbursement List in 2016-2018

PubMed Central

Catic, Tarik; Lekic, Lana; Zah, Vlad; Tabakovic, Vedad

2017-01-01

Introduction: Diabetes is reaching epidemiological scales worldwide. Beside health implications diabetes bears significant financial impact on health systems. Different treatment options aiming to prevent diabetes complications are available. Dipeptidyl-peptidase-IV (DPP-4) inhibitors like linagliptin are usually add-on therapy to metformin in order to achieve glycemic control. Expenditure for oral antidiabetic medicines in Bosnia and Herzegovina (B&H) is low accounting for only 2.53% of the total drug market expenditure. Linagliptin is not reimbursed in B&H mainly due to it’s perception of high cost medication. Aim: To assess budget impact (BI) of introducing linagliptin into health insurance reimbursement list in B&H through development of the budget impact model (BIM). Material and methods: Budget impact model was developed using Microsoft Excel 2010 based on current legislation and practice in B&H. Local epidemiology data and data on drug consumption from government reports in 2014 were used. Two scenarios with three-year time horizon have been developed: 1) without and 2) with linagliptin reimbursed and compared. Results: Inclusion of linagliptin into reimbursement list in Canton Sarajevo and Canton Tuzla would have positive budget impact on national level of B&H resulting in total savings of 18,194€, 235,570€ and 699,472€, in 2016, 2017 and 2018, respectively. Conclusion: Introduction of linagliptin into reimbursement list would decrease total costs for DPP-4 inhibitors and is favorable for positive decision on reimbursement in B&H. Applying BIM in decision making would assure better allocation and planning of resources at any region or administrative level in B&H. PMID:29109662

Factors Influencing the Prescribing Preferences of Physicians for Drug-Naive Patients with Type 2 Diabetes Mellitus in the Real-World Setting in Japan: Insight from a Web Survey.

PubMed

Murayama, Hiroki; Imai, Kota; Odawara, Masato

2018-06-01

The Japanese guidelines for type 2 diabetes mellitus (T2DM) emphasize individualization of treatment based on patient need and encourage physicians to select an appropriate oral antidiabetes drug (OAD). However, limited evidence is available on the factors influencing the selection by physicians (diabetes specialists and nonspecialists) of the first-line OAD to treat drug-naive patients with T2DM. A survey was designed to explore the treatment factors and patient characteristics that influence physicians when they choose an initial OAD to prescribe to a drug-naive patient with T2DM in a real-world setting in Japan. The 25-min web-based online survey consisted of simple and focused multiple-choice questions, and was circulated to physicians across eight selected regions in Japan. The primary endpoints were the proportions of physicians who considered particular treatment factors and patient characteristics when selecting the appropriate treatment for drug-naive T2DM patients. A total of 491 physicians participated in the survey. Dipeptidyl peptidase-4 inhibitors (DPP-4is) were the most-preferred first-line OADs, followed by metformin, of both specialists (69% vs. 60%) and nonspecialists (73% vs. 47%). The most influential factors when a DPP-4i was selected were found to be glycated hemoglobin (HbA1c), postprandial glucose (PPG)-lowering effect, and a low risk of hypoglycemia, which were considered by > 80% of physicians, whereas the key factors when metformin was selected were improvement in insulin resistance, low cost, low risk of hypoglycemia, and PPG- and HbA1c-lowering effects, which were considered by > 85% of physicians. Regression analysis revealed that the dominant reason for choosing DPP-4is over metformin was their ease of use in patients with renal impairment, whereas the dominant reasons for choosing metformin over DPP-4is were improvement in insulin resistance and low cost. The key patient characteristics driving the choice of DPP-4is or metformin as the first-line OAD by physicians were similar to those that influenced the treatment intensification decision (DPP-4is: PPG and renal function; metformin: age, BMI, insulin resistance, and renal function). In Japan, DPP-4is are the preferred first-line OADs, followed by metformin. The key treatment factors and patient characteristics considered when selecting DPP-4is or metformin are similar for both specialists and nonspecialists. These results may prompt further discussion of the differences in T2DM treatment between Japan and other counties. Novartis.

Drug utilization, safety, and effectiveness of exenatide, sitagliptin, and vildagliptin for type 2 diabetes in the real world: data from the Italian AIFA Anti-diabetics Monitoring Registry.

PubMed

Montilla, S; Marchesini, G; Sammarco, A; Trotta, M P; Siviero, P D; Tomino, C; Melchiorri, D; Pani, L

2014-12-01

In Italy, the reimbursed use of incretin mimetics and incretin enhancers was subject to enrollment of patients into a web-based system recording the general demographic and clinical data of patients. We report the utilization data of glucagon-like peptide 1 (GLP1) receptor agonists and dipeptidylpeptidase-4 (DPP4) inhibitors in clinical practice as recorded by the Italian Medicines Agency (AIFA) Monitoring Registry. From February 2008 to August 2010, 75,283 patients with type 2 diabetes were entered into the registry and treated with exenatide, sitagliptin, or vildagliptin. The treatment was administered to patients in a wide range of ages (≥75 years, n = 6125 cases), body mass index (BMI) (≥35 kg/m(2), n = 22,015), and metabolic control (HbA(1c) ≥ 11% ((96 mmol/mol), n = 3151). Overall, 1116 suspected adverse drug reactions were registered, including 12 cases of acute pancreatitis (six on exenatide). Hypoglycemic episodes mainly occurred in combination with sulfonylureas. Treatment discontinuation for the three drugs (logistic regression analysis) was negatively associated with the male gender and positively with baseline HbA1c, diabetes duration, and, limitedly to DPP-4 inhibitors, with BMI. Treatment discontinuation (including loss to follow-up, accounting for 21-26%) was frequent. Discontinuation for treatment failure occurred in 7.7% of cases (exenatide), 3.8% (sitagliptin), and 4.1% (vildagliptin), respectively, corresponding to 27-40% of all discontinuations, after excluding lost to follow-up. HbA1c decreased on average by 0.9-1.0% (9 mmol/mol). Body weight decreased by 3.5% with exenatide and by 1.0-1.5% with DPP-4 inhibitors. In the real world of Italian diabetes centers, prescriptions of incretins have been made in many cases outside the regulatory limits. Nevertheless, when appropriately utilized, incretins may grant results at least in line with pivotal trials. Copyright © 2014 Elsevier B.V. All rights reserved.

Inhibition of CD26/DPP IV attenuates ischemia/reperfusion injury in orthotopic mouse lung transplants: the pivotal role of vasoactive intestinal peptide.

PubMed

Jungraithmayr, Wolfgang; De Meester, Ingrid; Matheeussen, Veerle; Inci, Ilhan; Augustyns, Koen; Scharpé, Simon; Weder, Walter; Korom, Stephan

2010-04-01

The T cell activation Ag CD26/dipeptidylpeptidase IV (DPP IV) combines co-stimulatory and enzymatic properties. Catalytically, it functions as an exopeptidase, modulating biological activity of key chemokines and peptides. Here we investigated the effect of organ-specific inhibition of DPP IV catalytic activity on ischemia/reperfusion injury after extended ischemia in the mouse model of orthotopic single lung transplantation. C57BL/6 mice were syngeneically, transplanted, grafts were perfused and stored in Perfadex with (treated) or without (control) a DPP IV enzymatic activity inhibitor (AB192). Transplantation was performed after 18h cold ischemia time; following 2-h reperfusion, grafts were analyzed for oxygenation, thiobarbituric acid-reactive substances, histomorphology, and immunohistochemistry was performed for leukocyte Ag 6, myeloperoxidase, hemoxygenase 1, vasoactive intestinal protein (VIP), and real-time PCR for VIP. Treatment with the DPP IV inhibitor AB192 resulted in significant improvement of gas exchange, less lipid oxidation, preservation of parenchymal ultrastructure, reduced neutrophil infiltration, reduced myeloperoxidase expression, increased hemoxygenase 1 expression, pronounced expression of VIP in alveolar macrophages and increased mRNA expression of VIP. Inhibition of intragraft DPP IV catalytic activity with AB192 strikingly ameliorates ischemia/reperfusion injury after extended ischemia. Furthermore, preservation of endogenous intragraft VIP levels correlate with maintaining lung function and structural integrity. Copyright (c) 2009 Elsevier Inc. All rights reserved.

Fasting during Ramadan: efficacy, safety, and patient acceptability of vildagliptin in diabetic patients.

PubMed

Aziz, Kamran Ma

2015-01-01

Diabetes management during Ramadan fasting is challenging to the physician in terms of minimizing the risk of hypoglycemia. As compared to oral hypoglycemic agents (OHAs) and sulfonylureas (SUs), which carry a higher and significant risk of hypoglycemia, newer antidiabetic agents such as dipeptidyl peptidase-4 (DPP-4) inhibitors have demonstrated lower risk of hypoglycemia during Ramadan fasting, with better patient compliance. In addition to diabetes education and pre-Ramadan assessments, the physician should also consider use of DPP-4 inhibitors (such as vildagliptin) during Ramadan fasting to minimize the risk of hypoglycemia in type 2 diabetic subjects. Severe episodes of hypoglycemia have been demonstrated in recent research and clinical trials with OHAs/SUs. Conversely, these research observations have also demonstrated comparative safety and efficacy with lower risk of hypoglycemia associated with vildagliptin. Current research review has collected evidence-based clinical trials and observations for the drug vildagliptin to minimize the risk of hypoglycemia during Ramadan fasting, while at the same time focusing the role of diabetes self-management education (DSME), pre-Ramadan assessments, and patient care.

Fasting during Ramadan: efficacy, safety, and patient acceptability of vildagliptin in diabetic patients

PubMed Central

Aziz, Kamran MA

2015-01-01

Diabetes management during Ramadan fasting is challenging to the physician in terms of minimizing the risk of hypoglycemia. As compared to oral hypoglycemic agents (OHAs) and sulfonylureas (SUs), which carry a higher and significant risk of hypoglycemia, newer antidiabetic agents such as dipeptidyl peptidase-4 (DPP-4) inhibitors have demonstrated lower risk of hypoglycemia during Ramadan fasting, with better patient compliance. In addition to diabetes education and pre-Ramadan assessments, the physician should also consider use of DPP-4 inhibitors (such as vildagliptin) during Ramadan fasting to minimize the risk of hypoglycemia in type 2 diabetic subjects. Severe episodes of hypoglycemia have been demonstrated in recent research and clinical trials with OHAs/SUs. Conversely, these research observations have also demonstrated comparative safety and efficacy with lower risk of hypoglycemia associated with vildagliptin. Current research review has collected evidence-based clinical trials and observations for the drug vildagliptin to minimize the risk of hypoglycemia during Ramadan fasting, while at the same time focusing the role of diabetes self-management education (DSME), pre-Ramadan assessments, and patient care. PMID:25931826

Cardiovascular outcomes associated with canagliflozin versus other non-gliflozin antidiabetic drugs: population based cohort study.

PubMed

Patorno, Elisabetta; Goldfine, Allison B; Schneeweiss, Sebastian; Everett, Brendan M; Glynn, Robert J; Liu, Jun; Kim, Seoyoung C

2018-02-06

To evaluate the cardiovascular safety of canagliflozin, a sodium-glucose cotransporter 2 inhibitor for the treatment of type 2 diabetes mellitus, in direct comparisons with DPP-4 inhibitors (DPP-4i), GLP-1 receptor agonists (GLP-1RA), or sulfonylureas, as used in routine practice. Population based retrospective cohort study. Nationwide sample of patients with type 2 diabetes from a large de-identified US commercial healthcare database (Optum Clinformatics Datamart). Three pairwise 1:1 propensity score matched cohorts of patients with type 2 diabetes 18 years and older who initiated canagliflozin or a comparator non-gliflozin antidiabetic agent (ie, a DPP-4i, a GLP-1RA, or a sulfonylurea) between April 2013 and September 2015. The primary outcomes were heart failure admission to hospital and a composite cardiovascular endpoint (comprised of being admitted to hospital for acute myocardial infarction, ischemic stroke, or hemorrhagic stroke). Hazard ratios and 95% confidence intervals were estimated in each propensity score matched cohort controlling for more than 100 baseline characteristics. During a 30 month period, the hazard ratio for heart failure admission to hospital associated with canagliflozin was 0.70 (95% confidence interval 0.54 to 0.92) versus a DPP-4i (n=17 667 pairs), 0.61 (0.47 to 0.78) versus a GLP-1RA (20 539), and 0.51 (0.38 to 0.67) versus a sulfonylurea (17 354 ). The hazard ratio for the composite cardiovascular endpoint associated with canagliflozin was 0.89 (0.68 to 1.17) versus a DPP-4i, 1.03 (0.79 to 1.35) versus a GLP-1RA, and 0.86 (0.65 to 1.13) versus a sulfonylurea. Results were similar in sensitivity analyses further adjusting for baseline hemoglobin A1c levels and in subgroups of patients with and without prior cardiovascular disease or heart failure. In this large cohort study, canagliflozin was associated with a lower risk of heart failure admission to hospital and with a similar risk of myocardial infarction or stroke in direct comparisons with three different classes of non-gliflozin diabetes treatment alternatives as used in routine care. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Mouse-adapted MERS coronavirus causes lethal lung disease in human DPP4 knockin mice.

PubMed

Li, Kun; Wohlford-Lenane, Christine L; Channappanavar, Rudragouda; Park, Jung-Eun; Earnest, James T; Bair, Thomas B; Bates, Amber M; Brogden, Kim A; Flaherty, Heather A; Gallagher, Tom; Meyerholz, David K; Perlman, Stanley; McCray, Paul B

2017-04-11

The Middle East respiratory syndrome (MERS) emerged in Saudi Arabia in 2012, caused by a zoonotically transmitted coronavirus (CoV). Over 1,900 cases have been reported to date, with ∼36% fatality rate. Lack of autopsies from MERS cases has hindered understanding of MERS-CoV pathogenesis. A small animal model that develops progressive pulmonary manifestations when infected with MERS-CoV would advance the field. As mice are restricted to infection at the level of DPP4, the MERS-CoV receptor, we generated mice with humanized exons 10-12 of the mouse Dpp4 locus. Upon inoculation with MERS-CoV, human DPP4 knockin (KI) mice supported virus replication in the lungs, but developed no illness. After 30 serial passages through the lungs of KI mice, a mouse-adapted virus emerged (MERS MA ) that grew in lungs to over 100 times higher titers than the starting virus. A plaque-purified MERS MA clone caused weight loss and fatal infection. Virus antigen was observed in airway epithelia, pneumocytes, and macrophages. Pathologic findings included diffuse alveolar damage with pulmonary edema and hyaline membrane formation associated with accumulation of activated inflammatory monocyte-macrophages and neutrophils in the lungs. Relative to the parental MERS-CoV, MERS MA viruses contained 13-22 mutations, including several within the spike (S) glycoprotein gene. S-protein mutations sensitized viruses to entry-activating serine proteases and conferred more rapid entry kinetics. Recombinant MERS MA bearing mutant S proteins were more virulent than the parental virus in hDPP4 KI mice. The hDPP4 KI mouse and the MERS MA provide tools to investigate disease causes and develop new therapies.

Pharmacokinetics of the dipeptidyl peptidase 4 inhibitor saxagliptin in rats, dogs, and monkeys and clinical projections.

PubMed

Fura, Aberra; Khanna, Ashish; Vyas, Viral; Koplowitz, Barry; Chang, Shu-Ying; Caporuscio, Christian; Boulton, David W; Christopher, Lisa J; Chadwick, Kristina D; Hamann, Lawrence G; Humphreys, W Griffith; Kirby, Mark

2009-06-01

Saxagliptin is a potent, selective, reversible dipeptidyl peptidase 4 (DPP4) inhibitor specifically designed for extended inhibition of the DPP4 enzyme and is currently under development for the treatment of type-2 diabetes. The pharmacokinetics of saxagliptin were evaluated in rats, dogs, and monkeys and used to predict its human pharmacokinetics. Saxagliptin was rapidly absorbed and had good bioavailability (50-75%) in the species tested. The plasma clearance of saxagliptin was higher in rats (115 ml/min/kg) than in dogs (9.3 ml/min/kg) and monkeys (14.5 ml/min/kg) and was predicted to be low to moderate in humans. The plasma elimination half-life was between 2.1 and 4.4 h in rats, dogs, and monkeys, and both metabolism and renal excretion contributed to the overall elimination. The primary metabolic clearance pathway involved the formation of a significant circulating, pharmacologically active hydroxylated metabolite, M2. The volume of distribution values observed in rats, dogs, and monkeys (1.3-5.2 l/kg) and predicted for humans (2.7 l/kg) were greater than those for total body water, indicating extravascular distribution. The in vitro serum protein binding was low (< or =30%) in rats, dogs, monkeys, and humans. After intra-arterial administration of saxagliptin to Sprague-Dawley and Zucker diabetic fatty rats, higher levels of saxagliptin and M2 were observed in the intestine (a proposed major site of drug action) relative to that in plasma. Saxagliptin has prolonged pharmacodynamic properties relative to its plasma pharmacokinetic profile, presumably due to additional contributions from M2, distribution of saxagliptin and M2 to the intestinal tissue, and prolonged dissociation of both saxagliptin and M2 from DPP4.

[A novel dipeptidyl peptidase IV inhibitors developed through scaffold hopping and drug splicing strategy].

PubMed

Wang, Shan-Chun; Zeng, Li-Li; Ding, Yu-Yang; Zeng, Shao-Gao; Song, Hong-Rui; Hu, Wen-Hui; Xie, Hui

2014-01-01

Though all the marketed drugs of dipeptidyl peptidase IV inhibitors are structurally different, their inherent correlation is worthy of further investigation. Herein we rapidly discovered a novel DPP-IV inhibitor 8g (IC50 = 4.9 nmol.L-1) which exhibits as good activity and selectivity as the market drugs through scaffold hopping and drug splicing strategies based on alogliptin and linagliptin. This study demonstrated that the employment of classic medicinal chemistry strategy to the marketed drugs with specific target is an efficient approach to discover novel bioactive molecules.

Synthetic (+)-antroquinonol exhibits dual actions against insulin resistance by triggering AMP kinase and inhibiting dipeptidyl peptidase IV activities.

PubMed

Hsu, C Y; Sulake, R S; Huang, P-K; Shih, H-Y; Sie, H-W; Lai, Y-K; Chen, C; Weng, C F

2015-01-01

The fungal product (+)-antroquinonol activates AMP kinase (AMPK) activity in cancer cell lines. The present study was conducted to examine whether chemically synthesized (+)-antroquinonol exhibited beneficial metabolic effects in insulin-resistant states by activating AMPK and inhibiting dipeptidyl peptidase IV (DPP IV) activity. Effects of (+)-antroquinonol on DPP IV activity were measured with a DPPIV Assay Kit and effects on GLP-1-induced PKA were measured in AR42J cells. Translocation of the glucose transporter 4, GLUT4, induced either by insulin-dependent PI3K/AKT signalling or by insulin-independent AMPK activation, was assayed in differentiated myotubes. Glucose uptake and GLUT4 translocation were assayed in L6 myocytes. Mice with diet-induced obesity were used to assess effects of acute and chronic treatment with (+)-antroquinonol on glycaemic control in vivo. The results showed that of (+)-antroquinonol (100 μM ) inhibited the DPP IV activity as effectively as the clinically used inhibitor, sitagliptin. The phosphorylation of AMPK Thr(172) in differentiated myotubes was significantly increased by (+)-antroquinonol. In cells simultaneously treated with S961 (insulin receptor antagonist), insulin and (+)-antroquinonol, the combination of (+)-antroquinonol plus insulin still increased both GLUT4 translocation and glucose uptake. Further, (+)-antroquinonol and sitagliptin reduced blood glucose, when given acutely or chronically to DIO mice. Chemically synthesized (+)-antroquinonol exhibits dual effects to ameliorate insulin resistance, by increasing AMPK activity and GLUT4 translocation, along with inhibiting DPP IV activity. © 2014 The British Pharmacological Society.

Postauthorization safety study of the DPP-4 inhibitor saxagliptin: a large-scale multinational family of cohort studies of five outcomes

PubMed Central

Carbonari, Dena M; Saine, M Elle; Newcomb, Craig W; Roy, Jason A; Liu, Qing; Wu, Qufei; Cardillo, Serena; Haynes, Kevin; Kimmel, Stephen E; Reese, Peter P; Margolis, David J; Apter, Andrea J; Reddy, K Rajender; Hennessy, Sean; Bhullar, Harshvinder; Gallagher, Arlene M; Esposito, Daina B; Strom, Brian L

2017-01-01

Objective To evaluate the risk of serious adverse events among patients with type 2 diabetes mellitus initiating saxagliptin compared with oral antidiabetic drugs (OADs) in classes other than dipeptidyl peptidase-4 (DPP-4) inhibitors. Research design and methods Cohort studies using 2009–2014 data from two UK medical record data sources (Clinical Practice Research Datalink, The Health Improvement Network) and two USA claims-based data sources (HealthCore Integrated Research Database, Medicare). All eligible adult patients newly prescribed saxagliptin (n=110 740) and random samples of up to 10 matched initiators of non-DPP-4 inhibitor OADs within each data source were selected (n=913 384). Outcomes were hospitalized major adverse cardiovascular events (MACE), acute kidney injury (AKI), acute liver failure (ALF), infections, and severe hypersensitivity events, evaluated using diagnostic coding algorithms and medical records. Cox regression was used to determine HRs with 95% CIs for each outcome. Meta-analyses across data sources were performed for each outcome as feasible. Results There were no increased incidence rates or risk of MACE, AKI, ALF, infection, or severe hypersensitivity reactions among saxagliptin initiators compared with other OAD initiators within any data source. Meta-analyses demonstrated a reduced risk of hospitalization/death from MACE (HR 0.91, 95% CI 0.85 to 0.97) and no increased risk of hospitalization for infection (HR 0.97, 95% CI 0.93 to 1.02) or AKI (HR 0.99, 95% CI 0.88 to 1.11) associated with saxagliptin initiation. ALF and hypersensitivity events were too rare to permit meta-analysis. Conclusions Saxagliptin initiation was not associated with increased risk of MACE, infection, AKI, ALF, or severe hypersensitivity reactions in clinical practice settings. Trial registration number NCT01086280, NCT01086293, NCT01086319, NCT01086306, and NCT01377935; Results. PMID:28878934

Managing glycaemia in older people with type 2 diabetes: A retrospective, primary care-based cohort study, with economic assessment of patient outcomes.

PubMed

Gordon, Jason; McEwan, Phil; Evans, Marc; Puelles, Jorge; Sinclair, Alan

2017-05-01

To describe the relative health and economic outcomes associated with different second-line therapeutic approaches to manage glycaemia in older type 2 diabetes patients requiring escalation from metformin monotherapy. The Clinical Practice Research Datalink database was used to inform a retrospective observational cohort study of patients with type 2 diabetes treated with metformin monotherapy requiring escalation (addition or switch) to a second-line oral regimen from January 1, 2008 to December 31, 2014. Primary outcomes included time to first event (any event, myocardial infarction [MI], stroke, or composite of MI/stroke [major adverse cardiovascular event; MACE]) and total event rate. The health economic consequences associated with the choice of second-line treatment in older patients were assessed using the CORE Diabetes Model. A total of 10 484 patients were included; the majority escalated to second-line treatment with metformin + sulphonylurea (SU; 42%) or switched to SU monotherapy (28%). In multivariate adjusted analyses, total event rates for MACE with metformin + dipeptidyl peptidase-4 (DPP-4) inhibitor were significantly lower than with metformin + SU (0.61, 95% confidence interval [CI] 0.39-0.98), driven by a lower MI rate in the metformin + DPP-4 inhibitor group (0.52, 95% CI 0.27-0.99). Economic analyses estimated that metformin + DPP-4 inhibitor treatment was associated with the largest gain in health benefit, and cost-effectiveness ratios were favourable (<£30 000 per quality-adjusted life-year) for all second-line treatment scenarios. With respect to treatment choice, data from the present study support the notion of prescribing beyond metformin + SU, as alternative regimens have been shown to be associated with reduced outcomes risk and value for money. © 2016 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.

SGLT2-inhibitor and DPP-4 inhibitor improve brain function via attenuating mitochondrial dysfunction, insulin resistance, inflammation, and apoptosis in HFD-induced obese rats.

PubMed

Sa-Nguanmoo, Piangkwan; Tanajak, Pongpan; Kerdphoo, Sasiwan; Jaiwongkam, Thidarat; Pratchayasakul, Wasana; Chattipakorn, Nipon; Chattipakorn, Siriporn C

2017-10-15

Dipeptidyl peptidase-4 inhibitor (vildagliptin) has been shown to exert beneficial effects on insulin sensitivity and neuroprotection in obese-insulin resistance. Recent studies demonstrated the neuroprotection of the sodium-glucose co-transporter 2 inhibitor (dapagliflozin) in diabetes. However, the comparative effects of both drugs and a combination of two drugs on metabolic dysfunction and brain dysfunction impaired by the obese-insulin resistance have never been investigated. Forty male Wistar rats were divided into two groups, and received either a normal-diet (ND, n=8) or a high-fat diet (HFD, n=32) for 16weeks. At week 13, the HFD-fed rats were divided into four subgroups (n=8/subgroup) to receive either a vehicle, vildagliptin (3mg/kg/day) dapagliflozin (1mg/kg/day) or combined drugs for four weeks. ND rats were given a vehicle for four weeks. Metabolic parameters and brain function were investigated. The results demonstrated that HFD rats developed obese-insulin resistance and cognitive decline. Dapagliflozin had greater efficacy on improved peripheral insulin sensitivity and reduced weight gain than vildagliptin. Single therapy resulted in equally improved brain mitochondrial function, insulin signaling, apoptosis and prevented cognitive decline. However, only dapagliflozin improved hippocampal synaptic plasticity. A combination of the drugs had greater efficacy in improving brain insulin sensitivity and reducing brain oxidative stress than the single drug therapy. These findings suggested that dapagliflozin and vildagliptin equally prevented cognitive decline in the obese-insulin resistance, possibly through some similar mechanisms. Dapagliflozin had greater efficacy than vildagliptin for preserving synaptic plasticity, thus combined drugs could be the best therapeutic approach for neuroprotection in the obese-insulin resistance. Copyright © 2017 Elsevier Inc. All rights reserved.

Combined treatment with dipeptidyl peptidase-4 inhibitor (sitagliptin) and angiotensin-II type 1 receptor blocker (losartan) suppresses progression in a non-diabetic rat model of steatohepatitis.

PubMed

Okura, Yasushi; Namisaki, Tadashi; Moriya, Kei; Kitade, Mitsuteru; Takeda, Kosuke; Kaji, Kosuke; Noguchi, Ryuichi; Nishimura, Norihisa; Seki, Kenichiro; Kawaratani, Hideto; Takaya, Hiroaki; Sato, Shinya; Sawada, Yasuhiko; Shimozato, Naotaka; Furukawa, Masanori; Nakanishi, Keisuke; Saikawa, Soichiro; Kubo, Takuya; Asada, Kiyoshi; Yoshiji, Hitoshi

2017-11-01

Dipeptidyl peptidase-4 (DPP4) inhibitors (DPP4-I) are oral glucose-lowering drugs for type 2 diabetes mellitus. Previously, we reported that DPP4-I (sitagliptin) exerted suppressive effects on experimental liver fibrosis in rats. Blockade of the renin-angiotensin system by angiotensin-II type 1 receptor blocker (losartan), commonly used in the management of hypertension, has been shown to significantly alleviate hepatic fibrogenesis and carcinogenesis. We aimed to elucidate the effects and possible mechanisms of a sitagliptin + losartan combination on the progression of non-diabetic non-alcoholic steatohepatitis (NASH) in a rat model. To induce NASH, Fischer 344 rats were fed a choline-deficient L-amino acid-defined diet for 12 weeks. We elucidated the chemopreventive effects of sitagliptin + losartan, especially in conjunction with hepatic stellate cell (HSC) activation, angiogenesis, and oxidative stress, all known to play important roles in the progression of NASH. Sitagliptin + losartan suppressed choline-deficient L-amino acid-defined diet-induced hepatic fibrogenesis and carcinogenesis. The combination treatment exerted a greater inhibitory effect than monotherapy. These inhibitory effects occurred almost concurrently with the suppression of HSC activation, neovascularization, and oxidative stress. In vitro studies showed that sitagliptin + losartan inhibited angiotensin II-induced proliferation and expression of transforming growth factor-β1 and α1 (I)-procollagen mRNA of activated HSC and in vitro angiogenesis, in parallel with the suppression observed in in vivo studies. The widely and safely used sitagliptin + losartan combination treatment in clinical practice could be an effective strategy against NASH. © 2016 The Japan Society of Hepatology.

A molecular connection of Pterocarpus marsupium, Eugenia jambolana and Gymnema sylvestre with dipeptidyl peptidase-4 in the treatment of diabetes.

PubMed

Kosaraju, Jayasankar; Dubala, Anil; Chinni, Santhivardhan; Khatwal, Rizwan Basha; Satish Kumar, M N; Basavan, Duraiswamy

2014-02-01

Pterocarpus marsupium (PM) (Leguminosae), Eugenia jambolana (EJ) (Myrtaceae) and Gymnema sylvestre (GS) (Asclepiadaceae) are the most important medicinal plants in the Indian system of traditional medicine for the treatment of hyperglycemia. Dipeptidyl peptidase-4 (DPP-4) inhibitors are the emerging class of anti-diabetic agents. However, only few compounds are commercially available. Therefore, in the present study we tried to explore the naturally occurring PM, EJ and GS semi-standardized extracts for their potential DPP-4 inhibition in vitro and in vivo. DPP-4 inhibition was evaluated by in vitro inhibitory assay, and enzyme kinetics were calculated using one-phase exponential decay equation. Glucose load (2 g/kg) was administered to control and diabetic rats 30 min following extract administration (100, 200 and 400 mg/kg) orally once, and blood samples were withdrawn at 0, 0.5, 1, 1.5, 2 and 3 h to measure plasma active glucagon-like peptide-1 (GLP-1) levels. PM and EJ inhibit DPP-4 potently with IC50 values of 273.73 ± 2.96 and 278.94 ± 6.73 µg/mL, respectively, compared to GS (773.22 ± 9.21 µg/mL). PM, EJ and GS exhibit long duration of action with enzyme inhibitory half-lives of 462.3, 317.2 and 153.8 min, respectively. Extracts significantly increase GLP-1 levels compared to negative control groups and peak GLP-1 level was observed at 2 h for PM and EJ, whereas for GS it was at 1.5 h Taken together, results suggest the extracts may have potent DPP-4 inhibitory action, and their hypoglycemic action attributed through an increase in plasma active GLP-1 levels.

Cost-Effectiveness of Dapagliflozin as Add-On to Metformin for the Treatment of Type 2 Diabetes Mellitus in Greece.

PubMed

Tzanetakos, Charalampos; Tentolouris, Nicholas; Kourlaba, Georgia; Maniadakis, Nikos

2016-08-01

Type 2 diabetes mellitus (T2DM) is a chronic progressive disease that has been spread worldwide over the past three decades and associated with increased morbidity and mortality resulting in considerable socioeconomic implications for national healthcare systems. Effective management of disease is highly needed ensuring patients receive the best possible care within the available budget. The objective of this study was to evaluate the long-term cost-effectiveness of dapagliflozin, a sodium-glucose co-transporter-2 (SGLT-2) inhibitor, compared with a sulfonylurea (SU) or a dipeptidyl-peptidase-4 inhibitor (DPP-4i), when added to metformin, in T2DM patients inadequately controlled on metformin alone in Greece. The published and validated Cardiff diabetes model, a lifetime micro-simulation model, was adapted to a Greek healthcare setting to determine the incidence of micro- and macro-vascular complications and diabetes-specific and all-cause mortality. Clinical, cost, and utility data were retrieved from literature and assigned to model parameters to calculate total quality-adjusted life-years (QALYs) and total costs as well as incremental cost-effectiveness ratios (ICERs). The analysis was conducted from the perspective of a third-party payer in Greece. Uncertainty surrounding important model parameters was explored with univariate and probabilistic sensitivity analyses (PSA). Over a patient's lifetime, dapagliflozin was associated with 0.48 and 0.04 incremental QALYs compared with SU and DPP-4i, respectively, at additional costs of €5142 and €756, respectively. The corresponding ICERs were €10,623 and €17,695 per QALY gained versus the treatment with SU and DPP-4i, respectively. Results were robust across various univariate and scenario analyses. At the defined willingness-to-pay threshold of €34,000 per QALY gained, PSA estimated that treatment with dapagliflozin had a 100 % and 79.7 % probability of being cost-effective relative to the SU and DPP-4i treatments. Dapagliflozin in combination with metformin was shown to be a cost-effective treatment alternative for patients with T2DM whose metformin regimen does not provide sufficient glycemic control in a Greek healthcare setting.

Low DPP4 expression and activity in multiple sclerosis.

PubMed

Tejera-Alhambra, Marta; Casrouge, Armanda; de Andrés, Clara; Ramos-Medina, Rocío; Alonso, Bárbara; Vega, Janet; Albert, Matthew L; Sánchez-Ramón, Silvia

2014-02-01

Multiple sclerosis (MS) is a prototypic Th1/Th17 chronic autoimmune disease of the central nervous system. Dipeptidyl peptidase 4 (DPP4 or CD26) is a multifunctional molecule involved in autoimmune diseases' pathophysiology. We sought to integrate disparate pieces of data and analyze the plasma levels of sDPP4, DPP activity and DPP4 surface expression on T-cells in 129 MS patients with different clinical forms and 53 healthy controls, across two independent cohorts. Herein, we provide new evidence that sDPP4 concentration and DPP activity are significantly lower in MS patients than controls (p < 0.0001 and p < 0.01, respectively). In contrast, the frequency of circulating CD8(+)DPP4(hi) T-cells (p = 0.02) was increased in MS patients. This is the first study that simultaneously analyzes DPP4 expression and function in a large cohort of MS patients. Our data indicate a putative role for DPP4 in MS pathophysiology and suggest that a deeper understanding of surface versus shed DPP4 biology is warranted. Copyright © 2013 Elsevier Inc. All rights reserved.

Asymmetric synthesis of a potent, aminopiperidine-fused imidazopyridine dipeptidyl peptidase IV inhibitor.

PubMed

Xu, Feng; Corley, Edward; Zacuto, Michael; Conlon, David A; Pipik, Brenda; Humphrey, Guy; Murry, Jerry; Tschaen, David

2010-03-05

A practical asymmetric synthesis of a novel aminopiperidine-fused imidazopyridine dipeptidyl peptidase IV (DPP-4) inhibitor 1 has been developed. Application of a unique three-component cascade coupling with chiral nitro diester 7, which is easily accessed via a highly enantioselective Michael addition of dimethyl malonate to a nitrostyrene, allows for the assembly of the functionalized piperidinone skeleton in one pot. Through a base-catalyzed, dynamic crystallization-driven process, the cis-piperidionone 16a is epimerized to the desired trans isomer 16b, which is directly crystallized from the crude reaction stream in high yield and purity. Isomerization of the allylamide 16b in the presence of RhCl(3) is achieved without any epimerization of the acid/base labile stereogenic center adjacent to the nitro group on the piperidinone ring, while the undesired enamine intermediate is consumed to <0.5% by utilizing a trace amount of HCl generated from RhCl(3). The amino lactam 4, obtained through hydrogenation and hydrolysis, is isolated as its crystalline pTSA salt from the reaction solution directly, as such intramolecular transamidation has been dramatically suppressed via kinetic control. Finally, a Cu(I) catalyzed coupling-cyclization allows for the formation of the tricyclic structure of the potent DPP-4 inhibitor 1. The synthesis, which is suitable for large scale preparation, is accomplished in 23% overall yield.

Comparative analysis of the effects of alogliptin and vildagliptin on glucose metabolism in type 2 diabetes mellitus.

PubMed

Tanaka, Kenichi; Okada, Yosuke; Mori, Hiroko; Miyazaki, Megumi; Kuno, Fumi; Sonoda, Satomi; Sugai, Kei; Hajime, Maiko; Kurozumi, Akira; Narisawa, Manabu; Torimoto, Keiichi; Arao, Tadashi; Mine, Shinichiro; Tanaka, Yoshiya

2017-02-27

The aim of this 24-week, prospective randomized open-label study was to compare the effects of alogliptin and vildagliptin on glucose control, renal function, and lipid metabolism. In Study 1, DPP-4 inhibitor-naive type 2 diabetes (T2DM) were randomly assigned to alogliptin 25 mg/day or vildagliptin 50 mg twice daily. In Study 2, T2DM on treatment with 50 mg/day sitagliptin were switched to either 25 mg/day alogliptin or 50 mg twice daily vildagliptin. The primary endpoint was change in glycosylated hemoglobin (HbA1c) level at 24 weeks, while the secondary endpoints were changes in urinary albumin excretion and low-density lipoprotein cholesterol (LDL-C) levels at 24 weeks. In Study 1, HbA1c levels changed at 24-week by -0.5±0.7% in the alogliptin group (p=0.002, relative to baseline) and -0.7±0.9% in the vildagliptin group (p=0.001, relative to baseline), and the extent of these changes were comparable between the two groups (p=0.219). The decrease in log urinary albumin excretion was more significant in the vildagliptin group (p=0.008). In Study 2, HbA1c levels at 24-week changed by 0.2±0.7% in the switch-to-alogliptin group (p=0.007) and 0.0±0.6% in the switch-to-vildagliptin group (p=0.188), indicating a significant difference between the groups (p=0.003). In both studies, the changes in LDL-C levels were comparable between the two groups. The two drugs had comparable glucose-lowering effects in DPP-4 inhibitor-naive patients but the effect was more pronounced for vildagliptin in patients switched from sitagliptin. The results may point to subtle yet important differences between the two DPP-4 inhibitors. This trial was registered with UMIN (no. #000019022).

Biochemical and metabolic mechanisms by which dietary whey protein may combat obesity and Type 2 diabetes.

PubMed

Jakubowicz, Daniela; Froy, Oren

2013-01-01

Consumption of milk and dairy products has been associated with reduced risk of metabolic disorders and cardiovascular disease. Milk contains two primary sources of protein, casein (80%) and whey (20%). Recently, the beneficial physiological effects of whey protein on the control of food intake and glucose metabolism have been reported. Studies have shown an insulinotropic and glucose-lowering properties of whey protein in healthy and Type 2 diabetes subjects. Whey protein seems to induce these effects via bioactive peptides and amino acids generated during its gastrointestinal digestion. These amino acids and peptides stimulate the release of several gut hormones, such as cholecystokinin, peptide YY and the incretins gastric inhibitory peptide and glucagon-like peptide 1 that potentiate insulin secretion from β-cells and are associated with regulation of food intake. The bioactive peptides generated from whey protein may also serve as endogenous inhibitors of dipeptidyl peptidase-4 (DPP-4) in the proximal gut, preventing incretin degradation. Indeed, recently, DPP-4 inhibitors were identified in whey protein hydrolysates. This review will focus on the emerging properties of whey protein and its potential clinical application for obesity and Type 2 diabetes. Copyright © 2013 Elsevier Inc. All rights reserved.

Stromal derived factor 1α: A chemokine that delivers a two-pronged defence of the myocardium☆

PubMed Central

Bromage, Daniel I.; Davidson, Sean M.; Yellon, Derek M.

2014-01-01

Alleviating myocardial injury associated with ST elevation myocardial infarction is central to improving the global burden of coronary heart disease. The chemokine stromal cell-derived factor 1α (SDF-1α) has dual potential benefit in this regard. Firstly, SDF-1α is up-regulated in experimental and clinical studies of acute myocardial infarction (AMI) and regulates stem cell migration to sites of injury. SDF-1α delivery to the myocardium after AMI is associated with improved stem cell homing, angiogenesis, and left ventricular function in animal models, and improvements in heart failure and quality of life in humans. Secondly, SDF-1α may have a role in remote ischaemic conditioning (RIC), the phenomenon whereby non-lethal ischaemia–reperfusion applied to an organ or tissue remote from the heart protects the myocardium from lethal ischaemia–reperfusion injury (IRI). SDF-1α is increased in the serum of rats subjected to RIC and protects against myocardial IRI in ex vivo studies. Despite these potential pleiotropic effects, a limitation of SDF-1α is its short plasma half-life due to cleavage by dipeptidyl peptidase-4 (DPP-4). However, DPP-4 inhibitors increase the half-life of SDF-1α by preventing its degradation and are also protective against lethal IRI. In summary, SDF-1 potentially delivers a ‘two-pronged’ defence of the myocardium: acutely protecting it from IRI while simultaneously stimulating repair by recruiting stem cells to the site of injury. In this article we examine the evidence for acute and chronic cardioprotective roles of SDF-1α and discuss potential therapeutic manipulations of this mechanism with DPP-4 inhibitors to protect against lethal tissue injury in the clinical setting. PMID:24704323

Synthetic (+)-antroquinonol exhibits dual actions against insulin resistance by triggering AMP kinase and inhibiting dipeptidyl peptidase IV activities

PubMed Central

Hsu, C Y; Sulake, R S; Huang, P-K; Shih, H-Y; Sie, H-W; Lai, Y-K; Chen, C; Weng, C F

2015-01-01

BACKGROUND AND PURPOSE The fungal product (+)-antroquinonol activates AMP kinase (AMPK) activity in cancer cell lines. The present study was conducted to examine whether chemically synthesized (+)-antroquinonol exhibited beneficial metabolic effects in insulin-resistant states by activating AMPK and inhibiting dipeptidyl peptidase IV (DPP IV) activity. EXPERIMENTAL APPROACH Effects of (+)-antroquinonol on DPP IV activity were measured with a DPPIV Assay Kit and effects on GLP-1-induced PKA were measured in AR42J cells. Translocation of the glucose transporter 4, GLUT4, induced either by insulin-dependent PI3K/AKT signalling or by insulin-independent AMPK activation, was assayed in differentiated myotubes. Glucose uptake and GLUT4 translocation were assayed in L6 myocytes. Mice with diet-induced obesity were used to assess effects of acute and chronic treatment with (+)-antroquinonol on glycaemic control in vivo. KEY RESULTS The results showed that of (+)-antroquinonol (100 μM ) inhibited the DPP IV activity as effectively as the clinically used inhibitor, sitagliptin. The phosphorylation of AMPK Thr172 in differentiated myotubes was significantly increased by (+)-antroquinonol. In cells simultaneously treated with S961 (insulin receptor antagonist), insulin and (+)-antroquinonol, the combination of (+)-antroquinonol plus insulin still increased both GLUT4 translocation and glucose uptake. Further, (+)-antroquinonol and sitagliptin reduced blood glucose, when given acutely or chronically to DIO mice. CONCLUSIONS AND IMPLICATIONS Chemically synthesized (+)-antroquinonol exhibits dual effects to ameliorate insulin resistance, by increasing AMPK activity and GLUT4 translocation, along with inhibiting DPP IV activity. PMID:24977411

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Wenfei; Wang, Ying; Wang, Nianshuang

Middle East respiratory syndrome coronavirus (MERS-CoV) infects host cells through binding the receptor binding domain (RBD) on its spike glycoprotein to human receptor dipeptidyl peptidase 4 (hDPP4). Here, we report identification of critical residues on hDPP4 for RBD binding and virus entry through analysis of a panel of hDPP4 mutants. Based on the RBD–hDPP4 crystal structure we reported, the mutated residues were located at the interface between RBD and hDPP4, which potentially changed the polarity, hydrophobic or hydrophilic properties of hDPP4, thereby interfering or disrupting their interaction with RBD. Using surface plasmon resonance (SPR) binding analysis and pseudovirus infection assay,more » we showed that several residues in hDPP4–RBD binding interface were important on hDPP4–RBD binding and viral entry. These results provide atomic insights into the features of interactions between hDPP4 and MERS-CoV RBD, and also provide potential explanation for cellular and species tropism of MERS-CoV infection. - Highlights: • It has been demonstrated that MERS-CoV infects host cells through binding its envelope spike (S) glycoprotein to the host cellular receptor dipeptidyl peptidase 4 (DPP4). • To identify the critical residues on hDPP4 for RBD binding and virus entry, we constructed a panel of hDPP4 mutants based on structure-guided mutagenesis. • Using surface plasmon resonance (SPR) binding analysis and pseudovirus infection assay, we showed that several residues on hDPP4 had significant impacts on virus/receptor interactions and viral entry. • Our study has provided new insights into the features of interactions between hDPP4 and MERS-CoV RBD, and provides potential explanation for cellular and species tropism of MERS-CoV infection.« less

Using computer-aided drug design and medicinal chemistry strategies in the fight against diabetes.

PubMed

Semighini, Evandro P; Resende, Jonathan A; de Andrade, Peterson; Morais, Pedro A B; Carvalho, Ivone; Taft, Carlton A; Silva, Carlos H T P

2011-04-01

The aim of this work is to present a simple, practical and efficient protocol for drug design, in particular Diabetes, which includes selection of the illness, good choice of a target as well as a bioactive ligand and then usage of various computer aided drug design and medicinal chemistry tools to design novel potential drug candidates in different diseases. We have selected the validated target dipeptidyl peptidase IV (DPP-IV), whose inhibition contributes to reduce glucose levels in type 2 diabetes patients. The most active inhibitor with complex X-ray structure reported was initially extracted from the BindingDB database. By using molecular modification strategies widely used in medicinal chemistry, besides current state-of-the-art tools in drug design (including flexible docking, virtual screening, molecular interaction fields, molecular dynamics, ADME and toxicity predictions), we have proposed 4 novel potential DPP-IV inhibitors with drug properties for Diabetes control, which have been supported and validated by all the computational tools used herewith.

Comparative risk for cardiovascular diseases of dipeptidyl peptidase-4 inhibitors vs. sulfonylureas in combination with metformin: Results of a two-phase study.

PubMed

Enders, Dirk; Kollhorst, Bianca; Engel, Susanne; Linder, Roland; Verheyen, Frank; Pigeot, Iris

2016-01-01

The aim was to assess whether the use of additional data from the Disease Management Program (DMP) diabetes mellitus type 2 to minimize the potential for residual confounding will alter the estimated risk of either myocardial infarction, ischemic stroke or heart failure in patients with type 2 diabetes using sulfonylureas compared to dipeptidyl peptidase-4 (DPP-4) inhibitors in addition to metformin based on routine health care data. We conducted a nested two-phase case-control study using claims data of one German health insurance from 2004 to 2013 (phase 1) and data of the DMP from 2010 to 2013 (phase 2). Adjusted odds ratios (ORs) for the combined cardiovascular event myocardial infarction, ischemic stroke or heart failure were calculated using a two-phase logistic regression. Phase 1 comprised 3179 patients (289 cases; 2890 controls) and phase 2 comprised 1968 patients (168 cases; 1800 controls). We observed an adjusted OR of 0.83 for the combined cardiovascular event (95% CI: 0.61-1.13). We observed a non-significantly reduced risk for cardiovascular diseases in patients using DPP-4 inhibitors compared to sulfonylureas in addition to metformin. This finding was not altered by the inclusion of additional information of the DMP in the analysis. However, due to the low power of this study, further studies are needed to reproduce our findings. Copyright © 2016 Elsevier Inc. All rights reserved.

Adipose Dipeptidyl Peptidase-4 and Obesity

PubMed Central

Sell, Henrike; Blüher, Matthias; Klöting, Nora; Schlich, Raphaela; Willems, Miriam; Ruppe, Florian; Knoefel, Wolfram Trudo; Dietrich, Arne; Fielding, Barbara A.; Arner, Peter; Frayn, Keith N.; Eckel, Jürgen

2013-01-01

OBJECTIVE To study expression of the recently identified adipokine dipeptidyl peptidase-4 (DPP4) in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) of patients with various BMIs and insulin sensitivities, as well as to assess circulating DPP4 in relation to obesity and insulin sensitivity. RESEARCH DESIGN AND METHODS DPP4 expression was measured in SAT and VAT from 196 subjects with a wide range of BMIs and insulin sensitivities. DPP4 release was measured ex vivo in paired biopsies from SAT and VAT as well as in vivo from SAT of lean and obese patients. Circulating DPP4 was measured in insulin-sensitive and insulin-resistant BMI-matched obese patients. RESULTS DPP4 expression was positively correlated with BMI in both SAT and VAT, with VAT consistently displaying higher expression than SAT. Ex vivo release of DPP4 from adipose tissue explants was higher in VAT than in SAT in both lean and obese patients, with obese patients displaying higher DPP4 release than lean controls. Net release of DPP4 from adipose tissue was also demonstrated in vivo with greater release in obese subjects than in lean subjects and in women than in men. Insulin-sensitive obese patients had significantly lower circulating DPP4 than did obesity-matched insulin-resistant patients. In this experiment, DPP4 positively correlated with the amount of VAT, adipocyte size, and adipose tissue inflammation. CONCLUSIONS DPP4, a novel adipokine, has a higher release from VAT that is particularly pronounced in obese and insulin-resistant patients. Our data suggest that DPP4 may be a marker for visceral obesity, insulin resistance, and the metabolic syndrome. PMID:24130353

Diabetes and cardiovascular disease: the potential benefit of incretin-based therapies.

PubMed

Addison, Daniel; Aguilar, David

2011-04-01

The health burden of type 2 diabetes mellitus continues to increase worldwide. A substantial portion of this burden is due to the development of cardiovascular disease in patients with diabetes. Recent failures of clinical trials of intensive glucose control to reduce macrovascular events, coupled with reports of potential harm of certain diabetic therapy, have led to increased scrutiny as new diabetic therapies are developed. Incretin peptides are a group of gastrointestinal proteins that regulate glucose metabolism through multiple mechanisms, and incretin-based therapies have been developed to treat type 2 diabetes. These agents include glucagon-like peptide-1 (GLP-1) and dipeptidyl peptidase-IV (DPP-IV) inhibitors. In addition to effects on glucose homeostasis, growing evidence suggest that these peptides may also affect the cardiovascular system. In this review, we discuss recent findings concerning the potential, yet untested, benefits of incretin-based pharmacotherapy in the treatment of cardiovascular disease.

DPP and DSP are Necessary for Maintaining TGF-β1 Activity in Dentin

PubMed Central

Yamakoshi, Y.; Kinoshita, S.; Izuhara, L.; Karakida, T.; Fukae, M.; Oida, S.

2014-01-01

Porcine dentin sialophosphoprotein (DSPP) is the most abundant non-collagenous protein in dentin. It is processed by proteases into 3 independent proteins: dentin sialoprotein (DSP), dentin glycoprotein (DGP), and dentin phosphoprotein (DPP). We fractionated DPP and DSP along with TGF-β activity by ion exchange (IE) chromatography from developing pig molars and measured their alkaline phosphatase (ALP)-stimulating activity in human periodontal (HPDL) cells with or without TGF-β receptor inhibitor. We then purified TGF-β-unbound or -bound DPP and DSP by reverse-phase high-performance liquid chromatography (RP-HPLC) using the ALP-HPDL system. The TGF-β isoform bound to DPP and DSP was identified as being TGF-β1 by both ELISA and LC-MS/MS analysis. We incubated carrier-free human recombinant TGF-β1 (CF-hTGF-β1) with TGF-β-unbound DPP or DSP and characterized the binding on IE-HPLC using the ALP-HPDL system. When only CF-hTGF-β1 was incubated, approximately 3.6% of the ALP-stimulating activity remained. DPP and DSP rescued the loss of TGF-β1 activity. Approximately 19% and 10% of the ALP stimulating activities were retained by the binding of TGF-β to DPP and DSP, respectively. The type I collagen infrequently bound to CF-hTGF-β1. We conclude that both DPP and DSP help retain TGF-β1 activity in porcine dentin. PMID:24799420

Structural and mutational analyses of dipeptidyl peptidase 11 from Porphyromonas gingivalis reveal the molecular basis for strict substrate specificity

PubMed Central

Sakamoto, Yasumitsu; Suzuki, Yoshiyuki; Iizuka, Ippei; Tateoka, Chika; Roppongi, Saori; Fujimoto, Mayu; Inaka, Koji; Tanaka, Hiroaki; Yamada, Mitsugu; Ohta, Kazunori; Gouda, Hiroaki; Nonaka, Takamasa; Ogasawara, Wataru; Tanaka, Nobutada

2015-01-01

The dipeptidyl peptidase 11 from Porphyromonas gingivalis (PgDPP11) belongs to the S46 family of serine peptidases and preferentially cleaves substrates with Asp/Glu at the P1 position. The molecular mechanism underlying the substrate specificity of PgDPP11, however, is unknown. Here, we report the crystal structure of PgDPP11. The enzyme contains a catalytic domain with a typical double β-barrel fold and a recently identified regulatory α-helical domain. Crystal structure analyses, docking studies, and biochemical studies revealed that the side chain of Arg673 in the S1 subsite is essential for recognition of the Asp/Glu side chain at the P1 position of the bound substrate. Because S46 peptidases are not found in mammals and the Arg673 is conserved among DPP11s, we anticipate that DPP11s could be utilised as targets for antibiotics. In addition, the present structure analyses could be useful templates for the design of specific inhibitors of DPP11s from pathogenic organisms. PMID:26057589

Cost-effectiveness of dapagliflozin versus DPP-4 inhibitors as an add-on to Metformin in the Treatment of Type 2 Diabetes Mellitus from a UK Healthcare System Perspective.

PubMed

Charokopou, M; McEwan, P; Lister, S; Callan, L; Bergenheim, K; Tolley, K; Postema, R; Townsend, R; Roudaut, M

2015-11-05

Type 2 diabetes mellitus (T2DM) is a chronic, progressive condition where the primary treatment goal is to maintain control of glycated haemoglobin (HbA1c). In order for healthcare decision makers to ensure patients receive the highest standard of care within the available budget, the clinical benefits of each treatment option must be balanced against the economic consequences. The aim of this study was to assess the cost-effectiveness of dapagliflozin, the first-in-class sodium-glucose co-transporter 2 (SGLT2) inhibitor, compared with a dipeptidyl peptidase-4 inhibitor (DPP-4i), when added to metformin for the treatment of patients with T2DM inadequately controlled on metformin alone. The previously published and validated Cardiff diabetes model was used as the basis for this economic evaluation, with treatment effect parameters sourced from a systematic review and network meta-analysis. Costs, derived from a UK healthcare system perspective, and quality-adjusted life years (QALYs), were used to present the final outcome as an incremental cost-effectiveness ratio (ICER) over a lifetime horizon. Univariate and probabilistic sensitivity analyses (PSA) were carried out to assess uncertainty in the model results. Compared with DPP-4i, dapagliflozin was associated with a mean incremental benefit of 0.032 QALYs (95% confidence interval [CI]: -0.022, 0.140) and with an incremental cost of £216 (95% CI: £-258, £795). This resulted in an ICER point estimate of £6,761 per QALY gained. Sensitivity analysis determined incremental costs to be insensitive to variation in most parameters, with only the treatment effect on weight having a notable impact on the incremental QALYs; however, there were no scenarios which raised the ICER above £15,000 per QALY. The PSA estimated that dapagliflozin had an 85% probability of being cost-effective at a willingness-to-pay threshold of £20,000 per QALY gained. Dapagliflozin in combination with metformin was shown to be a cost-effective treatment option from a UK healthcare system perspective for patients with T2DM who are inadequately controlled on metformin alone.

Feedback suppression of meal-induced glucagon-like peptide-1 (GLP-1) secretion mediated through elevations in intact GLP-1 caused by dipeptidyl peptidase-4 inhibition: a randomized, prospective comparison of sitagliptin and vildagliptin treatment.

PubMed

Baranov, Oleg; Kahle, Melanie; Deacon, Carolyn F; Holst, Jens J; Nauck, Michael A

2016-11-01

To compare directly the clinical effects of vildagliptin and sitagliptin in patients with type 2 diabetes, with a special emphasis on incretin hormones and L-cell feedback inhibition induced by dipeptidyl peptidase (DPP-4) inhibition. A total of 24 patients (12 on a diet/exercise regimen, 12 on metformin) were treated, in randomized order, for 7-9 days, with either vildagliptin (50 mg twice daily = 100 mg/d), sitagliptin (100 mg once daily in those on diet, 50 mg twice daily in those on metformin treatment = 100 mg/d) or placebo (twice daily). A mixed-meal test was performed. Intact glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide concentrations were doubled by both DPP-4 inhibitors. Meal-related total GLP-1 responses were reduced by vildagliptin and sitagliptin treatment alike in the majority of patients (vildagliptin: p = 0.0005; sitagliptin: p = 0.019), but with substantial inter-individual variation. L-cell feedback appeared to be more pronounced in those whose intact GLP-1 relative to total GLP-1 increased more, and who had greater reductions in fasting plasma glucose after DPP-4 inhibition. K-cell feedback inhibition overall was not significant. There were no differences in any of the clinical variables (glycaemia, insulin and glucagon secretory responses) between vildagliptin and sitagliptin treatment. Vildagliptin and sitagliptin affected incretin hormones, glucose concentrations, insulin and glucagon secretion in a similar manner. Inter-individual variations in L-cell feedback inhibition may indicate heterogeneity in the clinical response to DPP-4 inhibition. © 2016 John Wiley & Sons Ltd.

Circulating dipeptidyl peptidase-4 activity correlates with measures of hepatocyte apoptosis and fibrosis in non-alcoholic fatty liver disease in type 2 diabetes mellitus and obesity: A dual cohort cross-sectional study.

PubMed

Williams, Kathryn H; Vieira De Ribeiro, Ana Júlia; Prakoso, Emilia; Veillard, Anne-Sophie; Shackel, Nicholas A; Brooks, Belinda; Bu, Yangmin; Cavanagh, Erika; Raleigh, Jim; McLennan, Susan V; McCaughan, Geoffrey W; Keane, Fiona M; Zekry, Amany; Gorrell, Mark D; Twigg, Stephen M

2015-11-01

Intrahepatic expression of dipeptidyl peptidase-4 (DPP4), and circulating DPP4 (cDPP4) levels and its enzymatic activity, are increased in non-alcoholic fatty liver disease (NAFLD) and in type 2 diabetes mellitus and/or obesity. DPP4 has been implicated as a causative factor in NAFLD progression but few studies have examined associations between cDPP4 activity and NAFLD severity in humans. This study aimed to examine the relationship of cDPP4 activity with measures of liver disease severity in NAFLD in subjects with diabetes and/or obesity. cDPP4 was measured in 106 individuals with type 2 diabetes who had transient elastography (Cohort 1) and 145 individuals with morbid obesity who had liver biopsy (Cohort 2). Both cohorts had caspase-cleaved keratin-18 (ccK18) measured as a marker of apoptosis. Natural log increases in cDPP4 activity were associated with increasing quartiles of ccK18 (Cohorts 1 and 2) and with median liver stiffness ≥10.3 kPa (Cohort 1) and significant fibrosis (F ≥ 2) on liver biopsy (Cohort 2). In diabetes and/or obesity, cDPP4 activity is associated with current apoptosis and liver fibrosis. Given the pathogenic mechanisms by which DPP4 may progress NAFLD, measurement of cDPP4 activity may have utility to predict disease progression and DPP4 inhibition may improve liver histology over time. © 2014 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

Inhibition of Xenobiotic-Degrading Hydrolases by Organophosphinates

DTIC Science & Technology

1986-07-01

TMB-4 doubled the rates of recovery. Concentrations of Lcarboxyl- CIprocaine in blood of mice were increased three-fold for 27 m I" exposure to 0-4...enzyme was found to have recovered 45.7% of its activity 24 h 35 after exposure to 4.87 x 10- 4 M EPP (Table 10). Neither rabbit liver carboxylesterase...case of a competitive mechanism of inhibition. It is possible that IPP and DPP were competitive inhibitors acting by occupation of the active site of

Patterns of glucose lowering drugs utilization in Portugal and in the Netherlands. Trends over time.

PubMed

Torre, Carla; Guerreiro, José; de Oliveira Martins, Sofia; Raposo, João Filipe; Martins, Ana Paula; Leufkens, Hubert

2015-12-01

To compare the temporal trends in the consumption patterns of glucose lowering drugs (GLD) between Portugal and the Netherlands from 2004 to 2013 and to examine possible reasons behind the cross-national variation found. All GLD (ATC pharmacological subgroup A10B) were selected for analysis. Consumption data were obtained for the 10-year period. Portuguese and Dutch drug estimates were obtained from nationwide databases. The consumption of GLD increased in Portugal from 52.9 defined daily dose per 1000 inhabitants per day (DHD) in 2004 to 70.0 DHD in 2013 and in the Netherlands from 44.9 DHD in 2004 to 50.7 DHD in 2013. In Portugal, the use of fixed-dose combinations, especially with dipeptidyl peptidase-4 inhibitors (DPP-4) increased remarkably and in 2013 represented almost a quarter of total GLD consumption. In the Netherlands, the use of combinations was residual. The consumption of GLD rose over the 10-year period in both countries. However, Portuguese overall consumption and costs of GLD were higher. The differentially rapid uptake of DPP-4 inhibitors in Portugal was the main driver of the cost difference. Copyright © 2015 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.

Sitagliptin inhibit human lymphocytes proliferation and Th1/Th17 differentiation in vitro.

PubMed

Pinheiro, Marcelo Maia; Stoppa, Caroline Lais; Valduga, Claudete Justina; Okuyama, Cristina Eunice; Gorjão, Renata; Pereira, Regina Mara Silva; Diniz, Susana Nogueira

2017-03-30

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a new class of anti-diabetic agents that are widely used in clinical practice to improve glycemic control in patients with type 2 diabetes. DPP-4 is also known as lymphocyte cell surface protein, CD26, and plays an important role in T-cell immunity. Recent studies suggest that DPP-4 inhibitors improve beta-cell function and attenuate autoimmunity in type 1 diabetic mouse models. To investigate the direct effect of DPP4 in immune response, human peripheral blood mononuclear cells (PBMC) from healthy volunteers were obtained by Ficoll gradient and cultivated in the absence (control) or presence of phytohemagglutinin (PHA), or stimulated with PHA and treated with sitagliptin. The immune modulation mechanisms analyzed were: cell proliferation, by MTT assay; cytokine quantification by ELISA or cytometric bead array (CBA), Th1/Th2/Th17 phenotyping by flow cytometric analysis and CD26 gene expression by real time PCR. The results showed that sitagliptin treatment inhibited the proliferation of PBMC-PHA stimulated cells in a dose dependent manner and decreased CD26 expression by these cells, suggesting that sitagliptin may interfere in CD26 expression, dimerization and cell signaling. Sitagliptin treatment not only inhibited IL-10 (p<0.05) and IFN-gamma (p=0.07) cytokines, but also completely abolish IL-6 expression by PBMCs (p<0.001). On the other hand, IL-4 were secreted in culture supernatants from sitagliptin treated cells. A statistically significant increase (p<0.05) in the ratio of TGF-beta/proliferation index after sitagliptin treatment (2627.97±1351.65), when comparing to untreated cells (646.28±376.94), was also demonstrated, indicating higher TGF-beta1 production by viable cells in cultures. Sitagliptin treatment induced a significantly (p<0.05) decrease in IL-17 and IFN-gamma intracellular expression compared with PHA alone. Also, the percentage of T CD4 + IL-17 + , T CD4 + IFNgamma + and T CD4 + IL-4 + cells were significantly reduced (p<0.05) by sitagliptin. Our data demonstrated an immunosuppressive effect of sitagliptin on Th1, Th17 and Th2 lymphocytes differentiation that leads to the generation of regulatory TGF-beta1 secreting cells with low CD26 gene expression that may influence the state of pancreatic beta-cells and controlling DM1 patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Modulation of substance P signaling by dipeptidyl peptidase-IV enzymatic activity in human glioma cell lines.

PubMed

Busek, P; Stremenová, J; Krepela, E; Sedo, A

2008-01-01

Dipeptidyl peptidase-IV (DPP-IV, CD26) is a serine protease almost ubiquitously expressed on cell surface and present in body fluids. DPP-IV has been suggested to proteolytically modify a number of biologically active peptides including substance P (SP) and the chemokine stromal cell derived factor-1alpha (SDF-1alpha, CXCL12). SP and SDF-1alpha have been implicated in the regulation of multiple biological processes and also induce responses that may be relevant for glioma progression. Both SP and SDF-1alpha are signaling through cell surface receptors and use intracellular calcium as a second messenger. The effect of DPP-IV on intracellular calcium mobilization mediated by SP and SDF-1alpha was monitored in suspension of wild type U373 and DPP-IV transfected U373DPPIV glioma cells using indicator FURA-2. Nanomolar concentrations of SP triggered a transient dose dependent increase in intracellular calcium rendering the cells refractory to repeated stimulation, while SDF-1 had no measurable effect. SP signaling in DPP-IV overexpressing U373DPPIV cells was not substantially different from that in wild type cells. However, preincubation of SP with the DPP-IV overexpressing cells lead to the loss of its signaling potential, which could be prevented with DPP-IV inhibitors. Taken together, DPP-IV may proteolytically inactivate local mediators involved in gliomagenesis.

Incretin-related drug therapy in heart failure.

PubMed

Vest, Amanda R

2015-02-01

The new pharmacological classes of GLP-1 agonists and DPP-4 inhibitors are now widely used in diabetes and have been postulated as beneficial in heart failure. These proposed benefits arise from the inter-related pathophysiologies of diabetes and heart failure (diabetes increases the risk of heart failure, and heart failure can induce insulin resistance) and also in light of the dysfunctional myocardial energetics seen in heart failure. The normal heart utilizes predominantly fatty acids for energy production, but there is some evidence to suggest that increased myocardial glucose uptake may be beneficial for the failing heart. Thus, GLP-1 agonists, which stimulate glucose-dependent insulin release and enhance myocardial glucose uptake, have become a focus of investigation in both animal models and humans with heart failure. Limited pilot data for GLP-1 agonists shows potential improvements in systolic function, hemodynamics, and quality of life, forming the basis for current phase II trials.

Post-Liver Transplantation Diabetes Mellitus: A Review of Relevance and Approach to Treatment.

PubMed

Peláez-Jaramillo, Maria J; Cárdenas-Mojica, Allison A; Gaete, Paula V; Mendivil, Carlos O

2018-04-01

Post-liver transplantation diabetes mellitus (PLTDM) develops in up to 30% of liver transplant recipients and is associated with increased risk of mortality and multiple morbid outcomes. PLTDM is a multicausal disorder, but the main risk factor is the use of immunosuppressive agents of the calcineurin inhibitor (CNI) family (tacrolimus and cyclosporine). Additional factors, such as pre-transplant overweight, nonalcoholic steatohepatitis and hepatitis C virus infection, may further increase risk of developing PLTDM. A diagnosis of PLTDM should be established only after doses of CNI and steroids are stable and the post-operative stress has been overcome. The predominant defect induced by CNI is insulin secretory dysfunction. Plasma glucose control must start immediately after the transplant procedure in order to improve long-term results for both patient and transplant. Among the better known antidiabetics, metformin and DPP-4 inhibitors have a particularly benign profile in the PLTDM context and are the preferred oral agents for long-term management. Insulin therapy is also an effective approach that addresses the prevailing pathophysiological defect of the disorder. There is still insufficient evidence about the impact of newer families of antidiabetics (GLP-1 agonists, SGLT-2 inhibitors) on PLTDM. In this review, we summarize current knowledge on the epidemiology, pathogenesis, course of disease and medical management of PLTDM.

Substrate complexes of human dipeptidyl peptidase III reveal the mechanism of enzyme inhibition

PubMed Central

Kumar, Prashant; Reithofer, Viktoria; Reisinger, Manuel; Wallner, Silvia; Pavkov-Keller, Tea; Macheroux, Peter; Gruber, Karl

2016-01-01

Human dipeptidyl-peptidase III (hDPP III) is a zinc-dependent hydrolase cleaving dipeptides off the N-termini of various bioactive peptides. Thus, the enzyme is likely involved in a number of physiological processes such as nociception and is also implicated in several forms of cancer. We present high-resolution crystal structures of hDPP III in complex with opioid peptides (Met-and Leu-enkephalin, endomorphin-2) as well as with angiotensin-II and the peptide inhibitor IVYPW. These structures confirm the previously reported large conformational change of the enzyme upon ligand binding and show that the structure of the closed conformation is independent of the nature of the bound peptide. The overall peptide-binding mode is also conserved ensuring the correct positioning of the scissile peptide bond with respect to the catalytic zinc ion. The structure of the angiotensin-II complex shows, how longer peptides are accommodated in the binding cleft of hDPP III. Differences in the binding modes allow a distinction between real substrates and inhibitory peptides or “slow” substrates. The latter displace a zinc bound water molecule necessitating the energetically much less favoured anhydride mechanism as opposed to the favoured promoted-water mechanism. The structural data also form the necessary framework for the design of specific hDPP III inhibitors. PMID:27025154

Comparison of effects of sitagliptin and voglibose on left ventricular diastolic dysfunction in patients with type 2 diabetes: results of the 3D trial.

PubMed

Oe, Hiroki; Nakamura, Kazufumi; Kihara, Hajime; Shimada, Kenei; Fukuda, Shota; Takagi, Tsutomu; Miyoshi, Toru; Hirata, Kumiko; Yoshikawa, Junichi; Ito, Hiroshi

2015-06-19

Left ventricular (LV) diastolic dysfunction is frequently observed in patients with type 2 diabetes. Dipeptidyl peptidase-4 inhibitor (DPP-4i) attenuates postprandial hyperglycemia (PPH) and may have cardio-protective effects. It remains unclear whether DPP-4i improves LV diastolic function in patients with type 2 diabetes, and, if so, it is attributable to the attenuation of PPH or to a direct cardiac effect of DPP-4i. We compared the effects of the DPP-4i, sitagliptin, and the alpha-glucosidase inhibitor, voglibose, on LV diastolic function in patients with type 2 diabetes. We conducted a prospective, randomized, open-label, multicenter study of 100 diabetic patients with LV diastolic dysfunction. Patients received sitagliptin (50 mg/day) or voglibose (0.6 mg/day). The primary endpoints were changes in the e' velocity and E/e' ratio from baseline to 24 weeks later. The secondary efficacy measures included HbA1c, GLP-1, lipid profiles, oxidative stress markers and inflammatory markers. The study was completed with 40 patients in the sitagliptin group and 40 patients in the voglibose group. There were no significant changes in the e' velocity and E/e' ratio from baseline to 24 weeks later in both groups. However, analysis of covariance demonstrated that pioglitazone use is an independent factor associated with changes in the e' and E/e' ratio. Among patients not using pioglitazone, e' increased and the E/e' ratio decreased in both the sitagliptin and voglibose groups. GLP-1 level increased from baseline to 24 weeks later only in the sitagliptin group (4.8 ± 4.7 vs. 7.3 ± 5.5 pmol/L, p < 0.05). The reductions in HbA1c and body weight were significantly greater in the sitagliptin group than in the voglibose group (-0.7 ± 0.6 % vs. -0.3 ± 0.4, p < 0.005; -1.3 ± 3.2 kg vs. 0.4 ± 2.8 kg, p < 0.05, respectively). There were no changes in lipid profiles and inflammatory markers in both groups. Our trial showed that sitagliptin reduces HbA1c levels more greatly than voglibose does, but that neither was associated with improvement in the echocardiographic parameters of LV diastolic function in patients with diabetes. Registered at http://www.umin.ac.jp under UMIN000003784.

Reduction of soluble dipeptidyl peptidase 4 levels in plasma of patients infected with Middle East respiratory syndrome coronavirus.

PubMed

Inn, Kyung-Soo; Kim, Yuri; Aigerim, Abdimadiyeva; Park, Uni; Hwang, Eung-Soo; Choi, Myung-Sik; Kim, Yeon-Sook; Cho, Nam-Hyuk

2018-05-01

Dipeptidyl peptidase 4 (DPP4) is a receptor for MERS-CoV. The soluble form of DPP4 (sDPP4) circulates systematically and can competitively inhibit MERS-CoV entry into host cells. Here, we measured the concentration of sDPP4 in the plasma and sputa of 14 MERS-CoV-infected patients of various degrees of disease severity. The concentration of sDPP4 in the plasma of MERS patients (474.76 ± 108.06 ng/ml) was significantly lower than those of healthy controls (703.42 ± 169.96 ng/ml), but there were no significant differences among the patient groups. Interestingly, plasma levels of IL-10 and EGF were negatively and positively correlated with sDPP4 concentrations, respectively. The sDPP4 levels in sputa were less than 300 ng/ml. Viral infection was inhibited by 50% in the presence of more than 8000 ng/ml of sDPP4. Therefore, sDPP4 levels in the plasma of MERS patients are significantly reduced below the threshold needed to exert an antiviral effect against MERS-CoV infection. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Serum Levels of Soluble CD26/Dipeptidyl Peptidase-IV in Type 2 Diabetes Mellitus and Its Association with Metabolic Syndrome and Therapy with Antidiabetic Agents in Malaysian Subjects.

PubMed

Ahmed, Radwan H; Huri, Hasniza Zaman; Al-Hamodi, Zaid; Salem, Sameer D; Muniandy, Sekaran

2015-01-01

A soluble form of CD26/dipeptidyl peptidase-IV (sCD26/DPP-IV) induces DPP-IV enzymatic activity that degrades incretin. We investigated fasting serum levels of sCD26/DPP-IV and active glucagon-like peptide-1 (GLP-1) in Malaysian patients with type 2 diabetes mellitus (T2DM) with and without metabolic syndrome (MetS), as well as the associations between sCD26/DPP-IV levels, MetS, and antidiabetic therapy. We assessed sCD26/DPP-IV levels, active GLP-1 levels, body mass index (BMI), glucose, insulin, A1c, glucose homeostasis indices, and lipid profiles in 549 Malaysian subjects (including 257 T2DM patients with MetS, 57 T2DM patients without MetS, 71 non-diabetics with MetS, and 164 control subjects without diabetes or metabolic syndrome). Fasting serum levels of sCD26/DPP-IV were significantly higher in T2DM patients with and without MetS than in normal subjects. Likewise, sCD26/DPP-IV levels were significantly higher in patients with T2DM and MetS than in non-diabetic patients with MetS. However, active GLP-1 levels were significantly lower in T2DM patients both with and without MetS than in normal subjects. In T2DM subjects, sCD26/DPP-IV levels were associated with significantly higher A1c levels, but were significantly lower in patients using monotherapy with metformin. In addition, no significant differences in sCD26/DPP-IV levels were found between diabetic subjects with and without MetS. Furthermore, sCD26/DPP-IV levels were negatively correlated with active GLP-1 levels in T2DM patients both with and without MetS. In normal subjects, sCD26/DPP-IV levels were associated with increased BMI, cholesterol, and LDL-cholesterol (LDL-c) levels. Serum sCD26/DPP-IV levels increased in T2DM subjects with and without MetS. Active GLP-1 levels decreased in T2DM patients both with and without MetS. In addition, sCD26/DPP-IV levels were associated with Alc levels and negatively correlated with active GLP-1 levels. Moreover, metformin monotherapy was associated with reduced sCD26/DPP-IV levels. In normal subjects, sCD26/DPP-IV levels were associated with increased BMI, cholesterol, and LDL-c.

Association of DPP4 Gene Polymorphisms with Type 2 Diabetes Mellitus in Malaysian Subjects

PubMed Central

Ahmed, Radwan H.; Huri, Hasniza Zaman; Al-Hamodi, Zaid; Salem, Sameer D.; Al-absi, Boshra; Muniandy, Sekaran

2016-01-01

Background Genetic polymorphisms of the Dipeptidyl Peptidase 4 (DPP4) gene may play a role in the etiology of type 2 diabetes mellitus (T2DM). This study aimed to investigate the possible association of single nucleotide polymorphisms (SNPs) of the DPP4 gene in Malaysian subjects with T2DM and evaluated whether they had an effect on the serum levels of soluble dipeptidyl peptidase 4 (sDPP-IV). Method Ten DPP4 SNPs were genotyped by TaqMan genotyping assays in 314 subjects with T2DM and 235 controls. Of these, 71 metabolic syndrome (MetS) subjects were excluded from subsequent analysis. The odds ratios (ORs) and their 95% confidence interval (CIs) were calculated using multiple logistic regression for the association between the SNPs of DPP4 and T2DM. In addition, the serum levels of sDPP-IV were investigated to evaluate the association of the SNPs of DPP4 with the sDPP-IV levels. Results Dominant, recessive, and additive genetic models were employed to test the association of DPP4 polymorphisms with T2DM, after adjusting for age, race, gender and BMI. The rs12617656 was associated with T2DM in Malaysian subjects in the recessive genetic model (OR = 1.98, p = 0.006), dominant model (OR = 1.95, p = 0.008), and additive model (OR = 1.63, p = 0.001). This association was more pronounced among Malaysian Indians, recessive (OR = 3.21, p = 0.019), dominant OR = 3.72, p = 0.003) and additive model (OR = 2.29, p = 0.0009). The additive genetic model showed that DPP4 rs4664443 and rs7633162 polymorphisms were associated with T2DM (OR = 1.53, p = 0.039), and (OR = 1.42, p = 0.020), respectively. In addition, the rs4664443 G>A polymorphism was associated with increased sDPP-IV levels (p = 0.042) in T2DM subjects. Conclusions DPP4 polymorphisms were associated with T2DM in Malaysian subjects, and linked to variations in sDPP-IV levels. In addition, these associations were more pronounced among Malaysian Indian subjects. PMID:27111895

Association of DPP4 Gene Polymorphisms with Type 2 Diabetes Mellitus in Malaysian Subjects.

PubMed

Ahmed, Radwan H; Huri, Hasniza Zaman; Al-Hamodi, Zaid; Salem, Sameer D; Al-Absi, Boshra; Muniandy, Sekaran

2016-01-01

Genetic polymorphisms of the Dipeptidyl Peptidase 4 (DPP4) gene may play a role in the etiology of type 2 diabetes mellitus (T2DM). This study aimed to investigate the possible association of single nucleotide polymorphisms (SNPs) of the DPP4 gene in Malaysian subjects with T2DM and evaluated whether they had an effect on the serum levels of soluble dipeptidyl peptidase 4 (sDPP-IV). Ten DPP4 SNPs were genotyped by TaqMan genotyping assays in 314 subjects with T2DM and 235 controls. Of these, 71 metabolic syndrome (MetS) subjects were excluded from subsequent analysis. The odds ratios (ORs) and their 95% confidence interval (CIs) were calculated using multiple logistic regression for the association between the SNPs of DPP4 and T2DM. In addition, the serum levels of sDPP-IV were investigated to evaluate the association of the SNPs of DPP4 with the sDPP-IV levels. Dominant, recessive, and additive genetic models were employed to test the association of DPP4 polymorphisms with T2DM, after adjusting for age, race, gender and BMI. The rs12617656 was associated with T2DM in Malaysian subjects in the recessive genetic model (OR = 1.98, p = 0.006), dominant model (OR = 1.95, p = 0.008), and additive model (OR = 1.63, p = 0.001). This association was more pronounced among Malaysian Indians, recessive (OR = 3.21, p = 0.019), dominant OR = 3.72, p = 0.003) and additive model (OR = 2.29, p = 0.0009). The additive genetic model showed that DPP4 rs4664443 and rs7633162 polymorphisms were associated with T2DM (OR = 1.53, p = 0.039), and (OR = 1.42, p = 0.020), respectively. In addition, the rs4664443 G>A polymorphism was associated with increased sDPP-IV levels (p = 0.042) in T2DM subjects. DPP4 polymorphisms were associated with T2DM in Malaysian subjects, and linked to variations in sDPP-IV levels. In addition, these associations were more pronounced among Malaysian Indian subjects.

DPP10 splice variants are localized in distinct neuronal populations and act to differentially regulate the inactivation properties of Kv4-based ion channels.

PubMed

Jerng, Henry H; Lauver, Aaron D; Pfaffinger, Paul J

2007-08-01

Dipeptidyl peptidase-like proteins (DPLs) and Kv-channel-interacting proteins (KChIPs) join Kv4 pore-forming subunits to form multi-protein complexes that underlie subthreshold A-type currents (I(SA)) in neuronal somatodendritic compartments. Here, we characterize the functional effects and brain distributions of N-terminal variants belonging to the DPL dipeptidyl peptidase 10 (DPP10). In the Kv4.2+KChIP3+DPP10 channel complex, all DPP10 variants accelerate channel gating kinetics; however, the splice variant DPP10a produces uniquely fast inactivation kinetics that accelerates with increasing depolarization. This DPP10a-specific inactivation dominates in co-expression studies with KChIP4a and other DPP10 isoforms. Real-time qRT-PCR and in situ hybridization analyses reveal differential expression of DPP10 variants in rat brain. DPP10a transcripts are prominently expressed in the cortex, whereas DPP10c and DPP10d mRNAs exhibit more diffuse distributions. Our results suggest that DPP10a underlies rapid inactivation of cortical I(SA), and the regulation of isoform expression may contribute to the variable inactivation properties of I(SA) across different brain regions.

The Dipeptidyl Peptidases 4, 8, and 9 in Mouse Monocytes and Macrophages: DPP8/9 Inhibition Attenuates M1 Macrophage Activation in Mice.

PubMed

Waumans, Yannick; Vliegen, Gwendolyn; Maes, Lynn; Rombouts, Miche; Declerck, Ken; Van Der Veken, Pieter; Vanden Berghe, Wim; De Meyer, Guido R Y; Schrijvers, Dorien; De Meester, Ingrid

2016-02-01

Atherosclerosis remains the leading cause of death in Western countries. Dipeptidyl peptidase (DPP) 4 has emerged as a novel target for the prevention and treatment of atherosclerosis. Family members DPP8 and 9 are abundantly present in macrophage-rich regions of atherosclerotic plaques, and DPP9 inhibition attenuates activation of human M1 macrophages in vitro. Studying this family in a mouse model for atherosclerosis would greatly advance our knowledge regarding their potential as therapeutic targets. We found that DPP4 is downregulated during mouse monocyte-to-macrophage differentiation. DPP8 and 9 expression seems relatively low in mouse monocytes and macrophages. Viability of primary mouse macrophages is unaffected by DPP4 or DPP8/9 inhibition. Importantly, DPP8/9 inhibition attenuates macrophage activation as IL-6 secretion is significantly decreased. Mouse macrophages respond similarly to DPP inhibition, compared to human macrophages. This shows that the mouse could become a valid model species for the study of DPPs as therapeutic targets in atherosclerosis.

Immunohistochemical localization of DPP10 in rat brain supports the existence of a Kv4/KChIP/DPPL ternary complex in neurons.

PubMed

Wang, Wan-Chen; Cheng, Chau-Fu; Tsaur, Meei-Ling

2015-03-01

Subthreshold A-type K(+) currents (ISA s) have been recorded from the cell bodies of hippocampal and neocortical interneurons as well as neocortical pyramidal neurons. Kv4 channels are responsible for the somatodendritic ISA s. It has been proposed that neuronal Kv4 channels are ternary complexes including pore-forming Kv4 subunits, K(+) channel-interacting proteins (KChIPs), and dipeptidyl peptidase-like proteins (DPPLs). However, colocalization evidence was still lacking. The distribution of DPP10 mRNA in rodent brain has been reported but its protein localization remains unknown. In this study, we generated a DPP10 antibody to label DPP10 protein in adult rat brain by immunohistochemistry. Absent from glia, DPP10 proteins appear mainly in the cell bodies of DPP10(+) neurons, not only at the plasma membrane but also in the cytoplasm. At least 6.4% of inhibitory interneurons in the hippocampus coexpressed Kv4.3, KChIP1, and DPP10, with the highest density in the CA1 strata alveus/oriens/pyramidale and the dentate hilus. Colocalization of Kv4.3/KChIP1/DPP10 was also detected in at least 6.9% of inhibitory interneurons scattered throughout the neocortex. Both hippocampal and neocortical Kv4.3/KChIP1/DPP10(+) inhibitory interneurons expressed parvalbumin or somatostatin, but not calbindin or calretinin. Furthermore, we found colocalization of Kv4.2/Kv4.3/KChIP3/DPP10 in neocortical layer 5 pyramidal neurons and olfactory bulb mitral cells. Together, although DPP10 is also expressed in some brain neurons lacking Kv4 (such as parvalbumin- and somatostatin-positive Golgi cells in the cerebellum), colocalization of DPP10 with Kv4 and KChIP at the plasma membrane of ISA -expressing neuron somata supports the existence of Kv4/KChIP/DPPL ternary complex in vivo. © 2014 Wiley Periodicals, Inc.

COX inhibition excites enteric nerves that affect motility, alkaline secretion, and permeability in rat duodenum.

PubMed

Nylander, O; Hällgren, A; Sababi, M

2001-11-01

In anesthetized rats, the cyclooxygenase (COX) inhibitor indomethacin induces duodenal motility, increases duodenal mucosal alkaline secretion (DMAS), and evokes a transient increase in duodenal paracellular permeability (DPP). To examine whether enteric nerves influence these responses, the duodenum was perfused with lidocaine. Motility was assessed by measuring intraluminal pressure, and DPP was determined as blood-to-lumen clearance of (51)Cr-EDTA. DMAS was assessed by titration. In control animals, few contractions occurred during saline perfusion and lidocaine did not alter this condition. Perfusion with 0.03-0.1% lidocaine did not affect DMAS or DPP whereas 0.3-1% lidocaine reduced DMAS and increased DPP. Indomethacin induced motility and doubled DMAS. Application of 0.03% lidocaine on the duodenal serosa reduced motility and DMAS whereas 0.03% lidocaine applied luminally inhibited DMAS only. Higher concentrations of lidocaine abolished the increase in DMAS and changed the motility pattern to numerous low-amplitude contractions, the latter effect being blocked by iloprost. The lidocaine-induced increases in DPP were markedly higher than in controls. We conclude that indomethacin activates enteric nerves that induce motility, increase DMAS, and decrease DPP.

Dipeptidyl-peptidase (DPP)-4 inhibitors and glucagon-like peptide (GLP)-1 analogues for prevention or delay of type 2 diabetes mellitus and its associated complications in people at increased risk for the development of type 2 diabetes mellitus.

PubMed

Hemmingsen, Bianca; Sonne, David P; Metzendorf, Maria-Inti; Richter, Bernd

2017-05-10

The projected rise in the incidence of type 2 diabetes mellitus (T2DM) could develop into a substantial health problem worldwide. Whether dipeptidyl-peptidase (DPP)-4 inhibitors or glucagon-like peptide (GLP)-1 analogues are able to prevent or delay T2DM and its associated complications in people at risk for the development of T2DM is unknown. To assess the effects of DPP-4 inhibitors and GLP-1 analogues on the prevention or delay of T2DM and its associated complications in people with impaired glucose tolerance, impaired fasting blood glucose, moderately elevated glycosylated haemoglobin A1c (HbA1c) or any combination of these. We searched the Cochrane Central Register of Controlled Trials; MEDLINE; PubMed; Embase; ClinicalTrials.gov; the World Health Organization (WHO) International Clinical Trials Registry Platform; and the reference lists of systematic reviews, articles and health technology assessment reports. We asked investigators of the included trials for information about additional trials. The date of the last search of all databases was January 2017. We included randomised controlled trials (RCTs) with a duration of 12 weeks or more comparing DPP-4 inhibitors and GLP-1 analogues with any pharmacological glucose-lowering intervention, behaviour-changing intervention, placebo or no intervention in people with impaired fasting glucose, impaired glucose tolerance, moderately elevated HbA1c or combinations of these. Two review authors read all abstracts and full-text articles and records, assessed quality and extracted outcome data independently. One review author extracted data which were checked by a second review author. We resolved discrepancies by consensus or the involvement of a third review author. For meta-analyses, we planned to use a random-effects model with investigation of risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, using 95% confidence intervals (CIs) for effect estimates. We assessed the overall quality of the evidence using the GRADE instrument. We included seven completed RCTs; about 98 participants were randomised to a DPP-4 inhibitor as monotherapy and 1620 participants were randomised to a GLP-1 analogue as monotherapy. Two trials investigated a DPP-4 inhibitor and five trials investigated a GLP-1 analogue. A total of 924 participants with data on allocation to control groups were randomised to a comparator group; 889 participants were randomised to placebo and 33 participants to metformin monotherapy. One RCT of liraglutide contributed 85% of all participants. The duration of the intervention varied from 12 weeks to 160 weeks. We judged none of the included trials at low risk of bias for all 'Risk of bias' domains and did not perform meta-analyses because there were not enough trials.One trial comparing the DPP-4 inhibitor vildagliptin with placebo reported no deaths (very low-quality evidence). The incidence of T2DM by means of WHO diagnostic criteria in this trial was 3/90 participants randomised to vildagliptin versus 1/89 participants randomised to placebo (very low-quality evidence). Also, 1/90 participants on vildagliptin versus 2/89 participants on placebo experienced a serious adverse event (very low-quality evidence). One out of 90 participants experienced congestive heart failure in the vildagliptin group versus none in the placebo group (very low-quality evidence). There were no data on non-fatal myocardial infarction, stroke, health-related quality of life or socioeconomic effects reported.All-cause and cardiovascular mortality following treatment with GLP-1 analogues were rarely reported; one trial of exenatide reported that no participant died. Another trial of liraglutide 3.0 mg showed that 2/1501 in the liraglutide group versus 2/747 in the placebo group died after 160 weeks of treatment (very low-quality evidence).The incidence of T2DM following treatment with liraglutide 3.0 mg compared to placebo after 160 weeks was 26/1472 (1.8%) participants randomised to liraglutide versus 46/738 (6.2%) participants randomised to placebo (very low-quality evidence). The trial established the risk for (diagnosis of) T2DM as HbA1c 5.7% to 6.4% (6.5% or greater), fasting plasma glucose 5.6 mmol/L or greater to 6.9 mmol/L or less (7.0 mmol/L or greater) or two-hour post-load plasma glucose 7.8 mmol/L or greater to 11.0 mmol/L (11.1 mmol/L). Altogether, 70/1472 (66%) participants regressed from intermediate hyperglycaemia to normoglycaemia compared with 268/738 (36%) participants in the placebo group. The incidence of T2DM after the 12-week off-treatment extension period (i.e. after 172 weeks) showed that five additional participants were diagnosed T2DM in the liraglutide group, compared with one participant in the placebo group. After 12-week treatment cessation, 740/1472 (50%) participants in the liraglutide group compared with 263/738 (36%) participants in the placebo group had normoglycaemia.One trial used exenatide and 2/17 participants randomised to exenatide versus 1/16 participants randomised to placebo developed T2DM (very low-quality evidence). This trial did not provide a definition of T2DM. One trial reported serious adverse events in 230/1524 (15.1%) participants in the liraglutide 3.0 mg arm versus 96/755 (12.7%) participants in the placebo arm (very low quality evidence). There were no serious adverse events in the trial using exenatide. Non-fatal myocardial infarction was reported in 1/1524 participants in the liraglutide arm and in 0/55 participants in the placebo arm at 172 weeks (very low-quality evidence). One trial reported congestive heart failure in 1/1524 participants in the liraglutide arm and in 1/755 participants in the placebo arm (very low-quality evidence). Participants receiving liraglutide compared with placebo had a small mean improvement in the physical component of the 36-item Short Form scale showing a difference of 0.87 points (95% CI 0.17 to 1.58; P = 0.02; 1 trial; 1791 participants; very low-quality evidence). No trial evaluating GLP-1-analogues reported data on stroke, microvascular complications or socioeconomic effects. There is no firm evidence that DPP-4 inhibitors or GLP-1 analogues compared mainly with placebo substantially influence the risk of T2DM and especially its associated complications in people at increased risk for the development of T2DM. Most trials did not investigate patient-important outcomes.

Pharmacokinetic and Pharmacodynamic Effects of Multiple-dose Administration of Omarigliptin, a Once-weekly Dipeptidyl Peptidase-4 Inhibitor, in Obese Participants With and Without Type 2 Diabetes Mellitus.

PubMed

Addy, Carol; Tatosian, Daniel; Glasgow, Xiaoli S; Gendrano, Isaias N; Kauh, Eunkyung; Martucci, Ashley; Johnson-Levonas, Amy O; Selverian, Diana; Matthews, Catherine Z; Gutierrez, Marie; Wagner, John A; Aubrey Stoch, S

2016-03-01

Omarigliptin (MK-3102) is a potent, oral, long-acting dipeptidyl peptidase (DPP)-4 inhibitor approved in Japan and in global development as a once-weekly treatment for type 2 diabetes mellitus (T2DM). The aim of this study was to investigate the pharmacokinetic (PK) and pharmacodynamic (PD) effects of omarigliptin in obese participants with and without T2DM. This was a Phase I, randomized, double-blind, placebo-controlled, multiple-dose study of 50-mg omarigliptin administered once weekly for 4 weeks. Participants included 24 obese but otherwise healthy subjects (panel A; omarigliptin, n = 18; placebo, n = 6) and 8 obese patients with T2DM (treatment naive, hemoglobin A1c ≥ 6.5% and ≤ 10.0% [panel B]; omarigliptin, n = 6; placebo, n = 2). Participants were 45 to 65 years of age with a body mass index of ≥ 30 and ≤ 40 kg/m(2). Blood sampling occurred at select time points, depending on the study panel, to evaluate the PK properties of omarigliptin, DPP-4 activity, active glucagon-like peptide 1 levels, and plasma glucose concentrations. Body weight was an exploratory end point. Due to sparse sampling in panel A, a thorough PK analysis was performed in obese patients with T2DM (panel B) only. PD analyses were performed in the overall study population (pooled panels A and B). PK profiles in obese participants with and without T2DM were similar to those observed in nonobese reference subjects (historical data). Steady state was achieved after 1 or 2 weekly doses in obese participants with and without T2DM. In obese patients with T2DM, omarigliptin was rapidly absorbed, with a median Tmax of 1 to 2.5 hours (days 1 and 22). Compared with those in reference subjects, the geometric mean ratios (95% CI) (Obese T2DM/reference) for steady-state plasma AUC0-168h, Cmax, and C168h were 0.80 (0.65-0.98), 0.86 (0.53-1.41), and 1.08 (0.88-1.33), respectively. Trough DPP-4 activity was inhibited by ~90%; postprandial (PP) 4-hour weighted mean active GLP-1 concentrations were increased ~2-fold; and PP glucose was significantly reduced with omarigliptin versus placebo in the pooled population. Omarigliptin was generally well-tolerated in the pooled population, and there were no hypoglycemic events. Consistent with other DPP-4 inhibitors, omarigliptin had no effect on body weight in this short-duration study. The administration of omarigliptin was generally well-tolerated in obese participants with and without T2DM, and the favorable PK and PD profiles support once-weekly dosing. Omarigliptin may provide an important once-weekly treatment option for patients with T2DM. ClinicalTrials.gov identifier: NCT01088711. Copyright © 2016 Elsevier HS Journals, Inc. All rights reserved.

The Role of Incretins in Glucose Homeostasis and Diabetes Treatment

PubMed Central

Kim, Wook; Egan, Josephine M.

2009-01-01

Incretins are gut hormones that are secreted from enteroendocrine cells into the blood within minutes after eating. One of their many physiological roles is to regulate the amount of insulin that is secreted after eating. In this manner, as well as others to be described in this review, their final common raison d’être is to aid in disposal of the products of digestion. There are two incretins, known as glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1), that share many common actions in the pancreas but have distinct actions outside of the pancreas. Both incretins are rapidly deactivated by an enzyme called dipeptidyl peptidase 4 (DPP4). A lack of secretion of incretins or an increase in their clearance are not pathogenic factors in diabetes. However, in type 2 diabetes (T2DM), GIP no longer modulates glucose-dependent insulin secretion, even at supraphysiological (pharmacological) plasma levels, and therefore GIP incompetence is detrimental to β-cell function, especially after eating. GLP-1, on the other hand, is still insulinotropic in T2DM, and this has led to the development of compounds that activate the GLP-1 receptor with a view to improving insulin secretion. Since 2005, two new classes of drugs based on incretin action have been approved for lowering blood glucose levels in T2DM: an incretin mimetic (exenatide, which is a potent long-acting agonist of the GLP-1 receptor) and an incretin enhancer (sitagliptin, which is a DPP4 inhibitor). Exenatide is injected subcutaneously twice daily and its use leads to lower blood glucose and higher insulin levels, especially in the fed state. There is glucose-dependency to its insulin secretory capacity, making it unlikely to cause low blood sugars (hypoglycemia). DPP4 inhibitors are orally active and they increase endogenous blood levels of active incretins, thus leading to prolonged incretin action. The elevated levels of GLP-1 are thought to be the mechanism underlying their blood glucose-lowering effects. PMID:19074620

Diacylglycerol Acyltransferase-1 (DGAT1) Inhibition Perturbs Postprandial Gut Hormone Release

PubMed Central

Lin, Hua V.; Chen, Dunlu; Shen, Zhu; Zhu, Lei; Ouyang, Xuesong; Vongs, Aurawan; Kan, Yanqing; Levorse, John M.; Kowalik, Edward J.; Szeto, Daphne M.; Yao, Xiaorui; Xiao, Jianying; Chen, Shirley; Liu, Jinqi; Garcia-Calvo, Marga; Shin, Myung K.; Pinto, Shirly

2013-01-01

Diacylglycerol acyltransferase-1 (DGAT1) is a potential therapeutic target for treatment of obesity and related metabolic diseases. However, the degree of DGAT1 inhibition required for metabolic benefits is unclear. Here we show that partial DGAT1 deficiency in mice suppressed postprandial triglyceridemia, led to elevations in glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) only following meals with very high lipid content, and did not protect from diet-induced obesity. Maximal DGAT1 inhibition led to enhanced GLP-1 and PYY secretion following meals with physiologically relevant lipid content. Finally, combination of DGAT1 inhibition with dipeptidyl-peptidase-4 (DPP-4) inhibition led to further enhancements in active GLP-1 in mice and dogs. The current study suggests that targeting DGAT1 to enhance postprandial gut hormone secretion requires maximal inhibition, and suggests combination with DPP-4i as a potential strategy to develop DGAT1 inhibitors for treatment of metabolic diseases. PMID:23336002

Does the treatment of type 2 diabetes mellitus with the DPP-4 inhibitor vildagliptin reduce HbA1c to a greater extent in Japanese patients than in Caucasian patients?

PubMed

Foley, James E; Bhosekar, Vaishali; Kawamori, Ryuzo

2016-01-01

Previous work suggests that Japanese patients with type 2 diabetes mellitus (T2DM) may respond more favorably to a DPP-4 (dipeptidyl peptidase-4) inhibitor than Caucasians. We aimed to compare the efficacy of the DPP-4 inhibitor vildagliptin (50 mg twice daily [bid]) between Japanese and Caucasian populations. This analysis pooled data from 19 studies of drug-naïve patients with T2DM who were treated for 12 weeks with vildagliptin 50 mg bid as monotherapy. The pool comprised Japanese patients (n=338) who had been treated in Japan and Caucasian patients (n=1,275) who were treated elsewhere. Change from baseline (Δ) in glycated hemoglobin (HbA1c) at 12 weeks (in millimoles per mole) versus baseline HbA1c (both in percentage National Glycohemoglobin Standardization Program units [NGSP%] and millimoles per mole) for each population was reported. Universal HbA1c in millimoles per mole was calculated from either the Japanese Diabetes Society or the NGSP% HbA1c standards. At baseline, mean values for Japanese and Caucasian patients, respectively, were as follows: age, 59 years and 56 years; % male, 69% and 57%. The average HbA1c was reduced from 7.90% to 6.96% (Japanese Diabetes Society) and from 8.57% to 7.50% (United States National Glycohemoglobin Standardization Program), while HbA1c was reduced from 63 mmol/mol to 53 mmol/mol and from 70 mmol/mol to 58 mmol/mol in Japanese and Caucasians, respectively. ΔHbA1c increased with increasing baseline in both populations. The slopes were the same (0.41, r (2)=0.36; and 0.41, r (2)=0.15), and the intercepts were 15.4 mmol/mol and 17.2 mmol/mol, respectively. In Japanese patients, mean ΔHbA1c was greater by 1.7 mmol/mol (0.2% NGSP HbA1c) at any given baseline HbA1c than in Caucasians (P=0.01). The present pooled analysis suggests that Japanese patients respond better to vildagliptin treatment compared with Caucasians. However, when glycemic control was corrected by using the same glycemic standard, the difference in HbA1c reduction between these populations was not clinically meaningful.

Sitagliptin, an dipeptidyl peptidase-4 inhibitor, does not alter the pharmacokinetics of the sulphonylurea, glyburide, in healthy subjects

PubMed Central

Mistry, Goutam C; Bergman, Arthur J; Zheng, Wei; Hreniuk, David; Zinny, Miguel A; Gottesdiener, Keith M; Wagner, John A; Herman, Gary A; Ruddy, Marcella

2008-01-01

AIMS Sitagliptin, a dipeptidyl peptidase-4 inhibitor, is an incretin enhancer that is approved for the treatment of Type 2 diabetes. Sitagliptin is mainly renally eliminated and not an inhibitor of CYP450 enzymes in vitro. Glyburide, a sulphonylurea, is an insulin sensitizer and mainly metabolized by CYP2C9. Since both agents may potentially be co-administered, the purpose of this study was to examine the effects of sitagliptin on glyburide pharmacokinetics. METHODS In this open-label, randomized, two-period crossover study, eight healthy normoglycaemic subjects, 22–44 years old, received single 1.25-mg doses of glyburide alone in one period and co-administered with sitagliptin on day 5 following a multiple-dose regimen for sitagliptin (200-mg q.d. ×6 days) in the other period. RESULTS The geometric mean ratios and 90% confidence intervals [(glyburide + sitagliptin)/glyburide] for AUC0–∞ and Cmax were 1.09 (0.96, 1.24) and 1.01 (0.84, 1.23), respectively. CONCLUSION Sitagliptin does not alter the pharmacokinetics of glyburide in healthy subjects. WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT No data are available on the potential drug interaction of sitagliptin and glyburide.Sitagliptin belongs to a new class of drugs called DPP-4 inhibitors recently approved for the treatment of Type 2 diabetes. WHAT THIS STUDY ADDS Glyburide is a commonly used sulphonylurea medication to treat Type 2 diabetes.Combination therapy is often required to achieve adequate glucose control in Type 2 diabetes.Sitagliptin does not appear to interfere with glyburide pharmacokinetics and therefore may be potentially co-administered with glyburide for the treatment of Type 2 diabetes. PMID:18503607

Multiprotein assembly of Kv4.2, KChIP3 and DPP10 produces ternary channel complexes with ISA-like properties.

PubMed

Jerng, Henry H; Kunjilwar, Kumud; Pfaffinger, Paul J

2005-11-01

Kv4 pore-forming subunits are the principal constituents of the voltage-gated K+ channel underlying somatodendritic subthreshold A-type currents (I(SA)) in neurones. Two structurally distinct types of Kv4 channel modulators, Kv channel-interacting proteins (KChIPs) and dipeptidyl-peptidase-like proteins (DPLs: DPP6 or DPPX, DPP10 or DPPY), enhance surface expression and modify functional properties. Since KChIP and DPL distributions overlap in the brain, we investigated the potential coassembly of Kv4.2, KChIP3 and DPL proteins, and the contribution of DPLs to ternary complex properties. Immunoprecipitation results show that KChIP3 and DPP10 associate simultaneously with Kv4.2 proteins in rat brain as well as heterologously expressing Xenopus oocytes, indicating Kv4.2 + KChIP3 + DPP10 multiprotein complexes. Consistent with ternary complex formation, coexpression of Kv4.2, KChIP3 and DPP10 in oocytes and CHO cells results in current waveforms distinct from the arithmetic sum of Kv4.2 + KChIP3 and Kv4.2 + DPP10 currents. Furthermore, the Kv4.2 + KChIP3 + DPP10 channels recover from inactivation very rapidly (tau(rec) approximately 18-26 ms), closely matching that of native I(SA) and significantly faster than the recovery of Kv4.2 + KChIP3 or Kv4.2 + DPP10 channels. For comparison, identical triple coexpression experiments were performed using DPP6 variants. While most results are similar, the Kv4.2 + KChIP3 + DPP6 channels exhibit inactivation that slows with increasing membrane potential, resulting in inactivation slower than that of Kv4.2 + KChIP3 + DPP10 channels at positive voltages. In conclusion, the native neuronal subthreshold A-type channel is probably a macromolecular complex formed from Kv4 and a combination of both KChIP and DPL proteins, with the precise composition of channel alpha and auxiliary subunits underlying tissue and regional variability in I(SA) properties.

A novel N-terminal motif of dipeptidyl peptidase-like proteins produces rapid inactivation of KV4.2 channels by a pore-blocking mechanism.

PubMed

Jerng, Henry H; Dougherty, Kevin; Covarrubias, Manuel; Pfaffinger, Paul J

2009-11-01

The somatodendritic subthreshold A-type K(+) current in neurons (I(SA)) depends on its kinetic and voltage-dependent properties to regulate membrane excitability, action potential repetitive firing, and signal integration. Key functional properties of the K(V)4 channel complex underlying I(SA) are determined by dipeptidyl peptidase-like proteins known as dipeptidyl peptidase 6 (DPP6) and dipeptidyl peptidase 10 (DPP10). Among the multiple known DPP10 isoforms with alternative N-terminal sequences, DPP10a confers exceptionally fast inactivation to K(V)4.2 channels. To elucidate the molecular basis of this fast inactivation, we investigated the structure-function relationship of the DPP10a N-terminal region and its interaction with the K(V)4.2 channel. Here, we show that DPP10a shares a conserved N-terminal sequence (MNQTA) with DPP6a (aka DPP6-E), which also induces fast inactivation. Deletion of the NQTA sequence in DPP10a eliminates this dramatic fast inactivation, and perfusion of MNQTA peptide to the cytoplasmic face of inside-out patches inhibits the K(V)4.2 current. DPP10a-induced fast inactivation exhibits competitive interactions with internally applied tetraethylammonium (TEA), and elevating the external K(+) concentration accelerates recovery from DPP10a-mediated fast inactivation. These results suggest that fast inactivation induced by DPP10a or DPP6a is mediated by a common N-terminal inactivation motif via a pore-blocking mechanism. This mechanism may offer an attractive target for novel pharmacological interventions directed at impairing I(SA) inactivation and reducing neuronal excitability.

Risk for Hospitalized Heart Failure Among New Users of Saxagliptin, Sitagliptin, and Other Antihyperglycemic Drugs: A Retrospective Cohort Study.

PubMed

Toh, Sengwee; Hampp, Christian; Reichman, Marsha E; Graham, David J; Balakrishnan, Suchitra; Pucino, Frank; Hamilton, Jack; Lendle, Samuel; Iyer, Aarthi; Rucker, Malcolm; Pimentel, Madelyn; Nathwani, Neesha; Griffin, Marie R; Brown, Nancy J; Fireman, Bruce H

2016-06-07

Recent postmarketing trials produced conflicting results about the risk for hospitalized heart failure (hHF) associated with dipeptidyl peptidase-4 (DPP-4) inhibitors, creating uncertainty about the safety of these antihyperglycemic agents. To examine the associations of hHF with saxagliptin and sitagliptin. Population-based, retrospective, new-user cohort study. 18 health insurance and health system data partners in the U.S. Food and Drug Administration's Mini-Sentinel program. Patients aged 18 years or older with type 2 diabetes who initiated therapy with saxagliptin, sitagliptin, pioglitazone, second-generation sulfonylureas, or long-acting insulin products from 2006 to 2013. Hospitalized HF, identified by International Classification of Diseases, Ninth Revision, Clinical Modification codes 402.x1, 404.x1, 404.x3, and 428.xx recorded as the principal discharge diagnosis. 78 553 saxagliptin users and 298 124 sitagliptin users contributed an average of 7 to 9 months of follow-up data to 1 or more pairwise comparisons. The risk for hHF was not higher with DPP-4 inhibitors than with the other study drugs. The hazard ratios from the disease risk score (DRS)-stratified analyses were 0.83 (95% CI, 0.70 to 0.99) for saxagliptin versus sitagliptin, 0.63 (CI, 0.47 to 0.85) for saxagliptin versus pioglitazone, 0.69 (CI, 0.54 to 0.87) for saxagliptin versus sulfonylureas, and 0.61 (CI, 0.50 to 0.73) for saxagliptin versus insulin. The DRS-stratified hazard ratios were 0.74 (CI, 0.64 to 0.85) for sitagliptin versus pioglitazone, 0.86 (CI, 0.77 to 0.95) for sitagliptin versus sulfonylureas, and 0.71 (CI, 0.64 to 0.78) for sitagliptin versus insulin. Results from the 1:1 propensity score-matched analyses were similar. Results were also similar in subgroups of patients with and without prior cardiovascular disease and in a subgroup defined by the 2 highest DRS deciles. Residual confounding and short follow-up. In this large cohort study, a higher risk for hHF was not observed in users of saxagliptin or sitagliptin compared with other selected antihyperglycemic agents. U.S. Food and Drug Administration.

Parkinson's Disease, Diabetes and Cognitive Impairment.

PubMed

Ashraghi, Mohammad R; Pagano, Gennaro; Polychronis, Sotirios; Niccolini, Flavia; Politis, Marios

2016-01-01

Parkinson's disease is a chronic neurodegenerative disorder characterized by a progressive loss of dopaminergic neurons. The pathophysiological mechanisms underlying Parkinson's are still unknown. Mitochondrial dysfunction, abnormal protein aggregation, increased neuroinflammation and impairment of brain glucose metabolism are shared processes among insulinresistance, diabetes and neurodegeneration and have been suggested as key mechanisms in development of Parkinson's and cognitive impairment. To review experimental and clinical evidence of underlying Parkinson's pathophysiology in common with diabetes and cognitive impairment. Anti-diabetic agents and recent patents for insulin-resistance that might be repositioned in the treatment of Parkinson's also have been included in this review. A narrative review using MEDLINE database. Common antidiabetic treatments such as DPP4 inhibitors, GLP-1 agonists and metformin have shown promise in the treatment of Parkinson's disease and cognitive impairment in animals and humans. Study of the pathophysiology of neurodegeneration common between diabetes and Parkinson's disease has given rise to new treatment possibilities. Patents published in the last 5 years could be used in novel approaches to Parkinson's treatment by targeting specific pathophysiology proteins, such as Nurr1, PINK1 and NrF2, while patents to improve penetration of the blood brain barrier could allow improved efficacy of existing treatments. Further studies using GLP-1 agonists and DPP-4 inhibitors to treat PD are warranted as they have shown promise.

Incretin-based therapy in combination with basal insulin: a promising tactic for the treatment of type 2 diabetes.

PubMed

Vora, J; Bain, S C; Damci, T; Dzida, G; Hollander, P; Meneghini, L F; Ross, S A

2013-02-01

Incretin therapies such as dipeptidyl peptidase-4 inhibitors (DPP-4Is) and GLP-1 receptor agonists (GLP-1RAs) have become well-established treatments for type 2 diabetes. Both drug classes reduce blood glucose through physiological pathways mediated by the GLP-1 receptor, resulting in glucose-dependent enhancement of residual insulin secretion and inhibition of glucagon secretion. In addition, the GLP-1RAs reduce gastrointestinal motility and appear to have appetite-suppressing actions and, so, are often able to produce clinically useful weight loss. The glucose-dependency of their glucagon-inhibiting and insulin-enhancing effects, together with their weight-sparing properties, make the incretin therapies a logical proposition for use in combination with exogenous basal insulin therapy. This combination offers the prospect of an additive or synergistic glucose-lowering effect without a greatly elevated risk of hypoglycaemia compared with insulin monotherapy, and any insulin-associated weight gain might also be mitigated. Furthermore, the incretin therapies can be combined with metformin, which is usually continued when basal insulin is introduced in type 2 diabetes. Although the combination of incretin and insulin therapy is currently not addressed in internationally recognized treatment guidelines, several clinical studies have assessed its use. The data, summarized in this review, are encouraging and show that glycaemic control is improved and weight gain is limited or reversed (especially with the combined use of GLP-1RAs and basal insulin), and that the use of an incretin therapy can also greatly reduce insulin dose requirements. The addition of basal insulin to established incretin therapy is straightforward, but insulin dose adjustment (though not discontinuation) is usually necessary if the sequence is reversed. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Comparisons of diabetic retinopathy events associated with glucose-lowering drugs in patients with type 2 diabetes mellitus: A network meta-analysis.

PubMed

Tang, Huilin; Li, Guangyao; Zhao, Ying; Wang, Fei; Gower, Emily W; Shi, Luwen; Wang, Tiansheng

2018-05-01

To assess the comparative effects of glucose-lowering drugs (GLDs) on the risk of diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM). We systematically searched Cochrane Central Register of Controlled Trials, PUBMED and EMBASE from inception to January 17, 2017 to identify randomized controlled trials (RCTs) that reported DR events among T2DM patients receiving any GLD. Random-effects pairwise and network meta-analyses were performed to calculate odds ratios (ORs) with 95% confidence intervals (CIs). A total of 37 independent RCTs with 1806 DR events among 100 928 patients with T2DM were included. The mean duration of diabetes was 8.7 years and mean baseline HbA1c was 8.2% (SD, 0.5%). Our network meta-analysis found that DPP-4i (OR, 1.20; 95% CI, 0.87-1.65), GLP-1RA (OR, 1.19; 95% CI, 0.94-1.52) and SGLT2 inhibitors (OR, 0.79; 95% CI, 0.49-1.28) were not associated with a higher risk of DR than placebo; however, a significantly increased risk of DR was associated with DPP-4i in the pairwise meta-analysis (OR, 1.27; 95% CI, 1.05-1.53). Sulfonylureas, on the other hand, were associated with a significantly increased risk of DR compared to placebo (OR, 1.67; 95% CI, 1.01-2.76). Current evidence indicates that the association between DPP-4i, GLP-1RA or SGLT2 inhibitors and risk of DR remains uncertain in patients with T2DM. Some evidence suggests that sulfonylureas may be associated with increased risk of DR. However, given that DR events were not systematically assessed, these effects should be explored further in large-scale, well-designed studies. © 2018 John Wiley & Sons Ltd.

Pharmacokinetics and pharmacodynamics of vildagliptin in healthy Chinese volunteers.

PubMed

Hu, Pei; Yin, Qi; Deckert, Fabienne; Jiang, Ji; Liu, Dongyang; Kjems, Lise; Dole, William P; He, Yan-Ling

2009-01-01

Vildagliptin is an orally effective, potent, and selective inhibitor of dipeptidyl peptidase IV (DPP-4) that improves glycemic control in patients with type 2 diabetes. This was a randomized, double-blind, placebo-controlled, time-lagged, parallel-group study in a total of 60 healthy Chinese participants. Single- and multiple-dose pharmacokinetics and pharmacodynamics, and safety and tolerability of vildagliptin were assessed following administration of 25, 50, 100, or 200 mg qd, or 50 mg bid. Vildagliptin was rapidly absorbed (tmax 1.5-2.0 hours) across the dose range of 25 to 200 mg and was quickly eliminated with a terminal elimination half-life (t1/2) of approximately 2 hours. Consistent with the short t1/2, no accumulation of vildagliptin was observed following the administration of multiple doses (accumulation factors were 1.00-1.05 across the 25- to 200-mg dose range). Vildagliptin AUC and Cmax values increased in an approximately dose-proportional fashion (dose proportionality constant beta 1.00-1.16). Administration of vildagliptin 25 to 200 mg led to rapid and near-complete (>95%) inhibition of DPP-4 activity for at least 4 hours after dosing, which was associated with increases in plasma active glucagon-like peptide-1 of up to 2- to 3-fold compared with placebo. The duration of DPP-4 inhibition increased with dose. Glucose and insulin levels were not affected by vildagliptin in healthy participants, consistent with the fact that the glucose-lowering effects of vildagliptin occur in a glucose-dependent fashion. Vildagliptin was well tolerated at the highest tested dose of 200 mg qd. Vildagliptin 25 to 200 mg qd exhibits approximately dose-proportional pharmacokinetics with no evidence of accumulation after multiple dosing in healthy Chinese participants. Vildagliptin demonstrates potent inhibition of DPP-4 activity with excellent tolerability at doses of up to and including 200 mg qd.

Effect of vildagliptin, a dipeptidyl peptidase 4 inhibitor, on cardiac hypertrophy induced by chronic beta-adrenergic stimulation in rats

PubMed Central

2014-01-01

Background Heart failure with left ventricular (LV) hypertrophy is often associated with insulin resistance and inflammation. Recent studies have shown that dipeptidyl peptidase 4 (DPP4) inhibitors improve glucose metabolism and inflammatory status. We therefore evaluated whether vildagliptin, a DPP4 inhibitor, prevents LV hypertrophy and improves diastolic function in isoproterenol-treated rats. Methods Male Wistar rats received vehicle (n = 20), subcutaneous isoproterenol (2.4 mg/kg/day, n = 20) (ISO), subcutaneous isoproterenol (2.4 mg/kg/day + oral vildagliptin (30 mg/kg/day, n = 20) (ISO-VL), or vehicle + oral vildagliptin (30 mg/kg/day, n = 20) (vehicle-VL) for 7 days. Results Blood pressure was similar among the four groups, whereas LV hypertrophy was significantly decreased in the ISO-VL group compared with the ISO group (heart weight/body weight, vehicle: 3.2 ± 0.40, ISO: 4.43 ± 0.39, ISO-VL: 4.14 ± 0.29, vehicle-VL: 3.16 ± 0.16, p < 0.05). Cardiac catheterization revealed that vildagliptin lowered the elevated LV end-diastolic pressure observed in the ISO group, but other parameters regarding LV diastolic function such as the decreased minimum dp/dt were not ameliorated in the ISO-VL group. Histological analysis showed that vildagliptin attenuated the increased cardiomyocyte hypertrophy and perivascular fibrosis, but it did not affect angiogenesis in cardiac tissue. In the ISO-VL group, quantitative PCR showed attenuation of increased mRNA expression of tumor necrosis factor-α, interleukin-6, insulin-like growth factor-l, and restoration of decreased mRNA expression of glucose transporter type 4. Conclusions Vildagliptin may prevent LV hypertrophy caused by continuous exposure to isoproterenol in rats. PMID:24521405

Structure-based design of an osteoclast-selective, nonpeptide Src homology 2 inhibitor with in vivo antiresorptive activity

PubMed Central

Shakespeare, William; Yang, Michael; Bohacek, Regine; Cerasoli, Franklin; Stebbins, Karin; Sundaramoorthi, Raji; Azimioara, Mihai; Vu, Chi; Pradeepan, Selvi; Metcalf, Chester; Haraldson, Chad; Merry, Taylor; Dalgarno, David; Narula, Surinder; Hatada, Marcos; Lu, Xiaode; van Schravendijk, Marie Rose; Adams, Susan; Violette, Shelia; Smith, Jeremy; Guan, Wei; Bartlett, Catherine; Herson, Jay; Iuliucci, John; Weigele, Manfred; Sawyer, Tomi

2000-01-01

Targeted disruption of the pp60src (Src) gene has implicated this tyrosine kinase in osteoclast-mediated bone resorption and as a therapeutic target for the treatment of osteoporosis and other bone-related diseases. Herein we describe the discovery of a nonpeptide inhibitor (AP22408) of Src that demonstrates in vivo antiresorptive activity. Based on a cocrystal structure of the noncatalytic Src homology 2 (SH2) domain of Src complexed with citrate [in the phosphotyrosine (pTyr) binding pocket], we designed 3′,4′-diphosphonophenylalanine (Dpp) as a pTyr mimic. In addition to its design to bind Src SH2, the Dpp moiety exhibits bone-targeting properties that confer osteoclast selectivity, hence minimizing possible undesired effects on other cells that have Src-dependent activities. The chemical structure AP22408 also illustrates a bicyclic template to replace the post-pTyr sequence of cognate Src SH2 phosphopeptides such as Ac-pTyr-Glu-Glu-Ile (1). An x-ray structure of AP22408 complexed with Lck (S164C) SH2 confirmed molecular interactions of both the Dpp and bicyclic template of AP22408 as predicted from molecular modeling. Relative to the cognate phosphopeptide, AP22408 exhibits significantly increased Src SH2 binding affinity (IC50 = 0.30 μM for AP22408 and 5.5 μM for 1). Furthermore, AP22408 inhibits rabbit osteoclast-mediated resorption of dentine in a cellular assay, exhibits bone-targeting properties based on a hydroxyapatite adsorption assay, and demonstrates in vivo antiresorptive activity in a parathyroid hormone-induced rat model. PMID:10944210

Saxagliptin Induces β-Cell Proliferation through Increasing Stromal Cell-Derived Factor-1α In Vivo and In Vitro.

PubMed

Li, Chun-Jun; Sun, Bei; Fang, Qian-Hua; Ding, Min; Xing, Yun-Zhi; Chen, Li-Ming; Yu, De-Min

2017-01-01

Dipeptidyl peptidase-4 inhibitors, such as saxagliptin, have been reported to have beneficial effects on β-cell function, but the specific underlying mechanism remains unclear. Stromal cell-derived factor-1α (SDF-1α), a chemokine produced in multiple organs, has been considered as a crucial regulator in promoting β-cell survival. Here, we speculate that SDF-1α might mediate the effect of saxagliptin on improving β-cell function. After 12-week saxagliptin treatment in high-fat diet/streptozotocin-induced diabetic rats, significant improvement in pancreas insulin secretion capacity evaluated by hyperglycemia clamp and increased β-cell to α-cell areas ratio were observed. Saxagliptin significantly induced β-cell proliferation and upregulated the expression of proliferation-related factors including c-myc and cyclind D1 determined with western blotting from the isolated islets. The expression/activity of DPP-4 was significantly reduced and paralleled with the restoration of SDF-1α levels in the saxagliptin-treated diabetic rats, subsequently the key WNT-signaling regulators, β-catenin, and AKT were activated. However, the effect of saxagliptin inducing β-cell proliferation was attenuated when we silenced the SDF-1α receptor (CXCR4) with RNAi in INS cell lines. Collectively, our data indicate that SDF-1α mediates the protective effect of saxagliptin on β-cell proliferation, suggesting that DPP-4 inhibitors have the potential role on delaying β-cell failure and SDF-1α could be a therapeutic target of β-cell regeneration.

Saxagliptin Induces β-Cell Proliferation through Increasing Stromal Cell-Derived Factor-1α In Vivo and In Vitro

PubMed Central

Li, Chun-Jun; Sun, Bei; Fang, Qian-Hua; Ding, Min; Xing, Yun-Zhi; Chen, Li-Ming; Yu, De-Min

2017-01-01

Dipeptidyl peptidase-4 inhibitors, such as saxagliptin, have been reported to have beneficial effects on β-cell function, but the specific underlying mechanism remains unclear. Stromal cell-derived factor-1α (SDF-1α), a chemokine produced in multiple organs, has been considered as a crucial regulator in promoting β-cell survival. Here, we speculate that SDF-1α might mediate the effect of saxagliptin on improving β-cell function. After 12-week saxagliptin treatment in high-fat diet/streptozotocin-induced diabetic rats, significant improvement in pancreas insulin secretion capacity evaluated by hyperglycemia clamp and increased β-cell to α-cell areas ratio were observed. Saxagliptin significantly induced β-cell proliferation and upregulated the expression of proliferation-related factors including c-myc and cyclind D1 determined with western blotting from the isolated islets. The expression/activity of DPP-4 was significantly reduced and paralleled with the restoration of SDF-1α levels in the saxagliptin-treated diabetic rats, subsequently the key WNT-signaling regulators, β-catenin, and AKT were activated. However, the effect of saxagliptin inducing β-cell proliferation was attenuated when we silenced the SDF-1α receptor (CXCR4) with RNAi in INS cell lines. Collectively, our data indicate that SDF-1α mediates the protective effect of saxagliptin on β-cell proliferation, suggesting that DPP-4 inhibitors have the potential role on delaying β-cell failure and SDF-1α could be a therapeutic target of β-cell regeneration. PMID:29230196

The DPP-IV inhibitor linagliptin and GLP-1 induce synergistic effects on body weight loss and appetite suppression in the diet-induced obese rat.

PubMed

Hansen, Henrik H; Hansen, Gitte; Paulsen, Sarah; Vrang, Niels; Mark, Michael; Jelsing, Jacob; Klein, Thomas

2014-10-15

Linagliptin is a dipeptidyl peptidase (DPP)-IV inhibitor approved for the treatment of type 2 diabetes. DPP-IV inhibitors are considered weight neutral, suggesting that elevation of endogenous incretin levels is not sufficient to promote weight loss per se. Here we evaluated the effect of linagliptin in combination with subcutaneous treatment of GLP-1(7-36) on body weight regulation in diet-induced obese (DIO) rats. Linagliptin administered perorally (1.5mg/kg, b.i.d.), but not subcutaneously (0.5mg/kg, b.i.d.), evoked a very modest body weight loss (2.2%) after 28 days of treatment. GLP-1 (0.5mg/kg, s.c.) treatment alone induced a body weight loss of 4.1%. In contrast, combined linagliptin (1.5mg/kg, p.o., or 0.5mg/kg, s.c.) and GLP-1 (0.5mg/kg) treatment evoked a marked anorectic response with both routes of linagliptin administration being equally effective on final body weight loss (7.5-8.0%). In comparison, liraglutide monotherapy (0.2mg/kg, s.c., b.i.d.) reduced body weight by 10.1%. Interestingly, the weight lowering effect of combined linagliptin and GLP-1 treatment was associated with a marked increase in chow preference, being more pronounced as compared to liraglutide treatment. In addition, linagliptin and GLP-1 co-treatment, but not liraglutide, specifically increased prepro-dynorphin mRNA levels in the caudate-putamen, an effect not obtained with administration of the compounds individually. In conclusion, co-treatment with linagliptin and GLP-1 synergistically reduces body weight in obese rats. The anti-obesity effect was caused by appetite suppression with a concomitant change in diet preference, which may potentially be associated with increased dynorphin activity in forebrain regions involved in reward anticipation and habit learning. Copyright © 2014 Elsevier B.V. All rights reserved.

A New Approach to Study Properties of Isolated Predipocytes Following In Vivo Exposure to Hypoxia

NASA Astrophysics Data System (ADS)

Chowdhury, Helena H.; Velebit Markovic, Jelena; Radic, Natasa; Francic, Vito; Mekjavic, Igor B.; Eiken, Ola; Zorec, Robert

2013-02-01

In the present study we developed a novel approach to study the properties of isolated human preadipocytes from subjects exposed to conditions of hypoxia equivalent to an altitude of 4000 m. By using confocal microscopy we studied the expression of dipeptidyl peptidase 4 (DPP4) in preadipocytes from adult normal-weight males. DPP4 is a transmembrane glycoprotein with enzymatic activity that cleaves N-terminal dipeptides from a diverse range of substrates. The activity of DPP4 is implicated in immune response as well as in glucose homeostasis. To gain insights into the pathophysiological role of DPP4 in insulin resistance we here explored DPP4 expression during prolonged exposure to hypoxia, an experimental model of obesity onset. We used here a rapid method to isolate cells from biopsies and immunolabelled them with antibodies. Then cells were prepared for the analysis with confocal microscopy. The results show that a prolonged exposure to hypoxic environment appears to increases the expression of DPP4 on preadipocytes.

Evaluation of pharmacokinetic and pharmacodynamic parameters following single dose of sitagliptin in healthy Indian males.

PubMed

Sangle, Ganesh V; Patil, Mohan; Deshmukh, Nitin J; Shengule, Sushant A; Kamble, Shantibhushan; Vuppalavanchu, Kiran Kumar; Kale, Sushil; Baig, Mirza Layeeq Ahmed; Singh, Geetchandra; Shaikh, Javed; Tripathi, Jitendra; Aravindababu, P

2018-05-01

Sitagliptin, a dipeptidyl peptidase (DPP)-IV inhibitor approved for the treatment of type 2 diabetes, is reported to be more efficacious in Indian patients than non-Indian patient population. The objective of the study was to evaluate pharmacokinetic and pharmacodynamic (PK/PD) parameters of single-dose sitagliptin 100 mg (Januvia) in healthy Indian male participants. In a randomised, single-dose, open-label, three-treatment, three-period, three-sequence, crossover bioavailability study, 18 healthy male participants received single-dose of sitagliptin under fasted and fed conditions. PK parameters (C max , T max , AUC 0-∞ and t 1/2 ) were determined using Phoenix WinNonlin software. PD parameters [DPP-IV inhibition, active glucagon-like peptide-1 (GLP-1) and insulin] were determined using established methods. PK parameters expressed in mean (SD) were C max 491.7 (135.9) ng/mL; AUC 0-∞ 4256.1 (509.9) ng· hr/mL, T max 2.9 (1.0) hr and t 1/2 10.4 (3.0) hr. The weighted average (WA) plasma DPP-4 inhibition over 24 h was 89.6% and WA of plasma active GLP-1 over 2 h after standardised meal (geometric mean ratio) was 11.1 (9.9) pM/L which is two- to- four fold higher compared to that reported in other populations. The mean average (SD) AUC of plasma insulin over 2 h of standardised meal was 47.9 (24.9) μIU/mL. Although, there are differences in pharmacokinetic parameters, no clinically meaningful differences were observed with respect to DPP-IV inhibition between Indian and non-Indian population.

Lysosomal degradation of cholecystokinin-(29-33)-amide in mouse brain is dependent on tripeptidyl peptidase-I: implications for the degradation and storage of peptides in classical late-infantile neuronal ceroid lipofuscinosis.

PubMed Central

Bernardini, Francesca; Warburton, Michael J

2002-01-01

Tripeptidyl peptidase-I (TPP-I) is a lysosomal exopeptidase which removes tripeptides from the N-terminus of small peptides. Mutations in the TPP-I gene result in a lethal neurodegenerative disease, classical late-infantile neuronal ceroid lipofuscinosis (CLN2). This disease is characterized by the accumulation of proteinaceous and autofluorescent material within the lysosomes of neurons, which undergo massive cell death during the course of the disease. The absence of TPP-I may result in the lysosomal accumulation of small peptides and proteins, which eventually compromises lysosomal functions critical to the survival of neurons. To investigate the metabolism of small peptides, we have studied the degradation of cholecystokinin-(29-33)-amide (GWMDF-NH2; cholecystokinin C-terminal pentapeptide) by lysosomal fractions isolated from mouse brain and several other tissues. GWMDF-NH2 is cleaved at only one peptide bond by brain lysosomes, to produce GWM and DF-NH2. Inhibitor studies demonstrate that this reaction is catalysed by TPP-I. In contrast, lysosomal fractions from other mouse tissues additionally cleave a second peptide bond to produce GW and MDF-NH2. Inhibitor studies indicate that this reaction is catalysed by dipeptidyl peptidase-I (DPP-I; cathepsin C). Inhibitors of TPP-I are sufficient to completely block the degradation of GWMDF-NH2 by brain, but inhibitors of both TPP-I and DPP-I are required to completely inhibit the degradation of GWMDF-NH2 by other mouse tissues. Enzyme assays confirm the low activity of DPP-I in brain. An unrelated neuropeptide, neuromedin B, is degraded by a pathway that is partially dependent on TPP-I. These results indicate that TPP-I is required for the partial or complete digestion of certain neuropeptides by brain lysosomes. In the absence of TPP-I, neuropeptides or their degradation products will accumulate in brain lysosomes and may contribute to the pathogenesis of CLN2. Other tissues are spared because they express another peptidase, DPP-I, which has extensive activity on peptides and can compensate for the loss of TPP-I. PMID:12038963

Lysosomal degradation of cholecystokinin-(29-33)-amide in mouse brain is dependent on tripeptidyl peptidase-I: implications for the degradation and storage of peptides in classical late-infantile neuronal ceroid lipofuscinosis.

PubMed

Bernardini, Francesca; Warburton, Michael J

2002-09-01

Tripeptidyl peptidase-I (TPP-I) is a lysosomal exopeptidase which removes tripeptides from the N-terminus of small peptides. Mutations in the TPP-I gene result in a lethal neurodegenerative disease, classical late-infantile neuronal ceroid lipofuscinosis (CLN2). This disease is characterized by the accumulation of proteinaceous and autofluorescent material within the lysosomes of neurons, which undergo massive cell death during the course of the disease. The absence of TPP-I may result in the lysosomal accumulation of small peptides and proteins, which eventually compromises lysosomal functions critical to the survival of neurons. To investigate the metabolism of small peptides, we have studied the degradation of cholecystokinin-(29-33)-amide (GWMDF-NH2; cholecystokinin C-terminal pentapeptide) by lysosomal fractions isolated from mouse brain and several other tissues. GWMDF-NH2 is cleaved at only one peptide bond by brain lysosomes, to produce GWM and DF-NH2. Inhibitor studies demonstrate that this reaction is catalysed by TPP-I. In contrast, lysosomal fractions from other mouse tissues additionally cleave a second peptide bond to produce GW and MDF-NH2. Inhibitor studies indicate that this reaction is catalysed by dipeptidyl peptidase-I (DPP-I; cathepsin C). Inhibitors of TPP-I are sufficient to completely block the degradation of GWMDF-NH2 by brain, but inhibitors of both TPP-I and DPP-I are required to completely inhibit the degradation of GWMDF-NH2 by other mouse tissues. Enzyme assays confirm the low activity of DPP-I in brain. An unrelated neuropeptide, neuromedin B, is degraded by a pathway that is partially dependent on TPP-I. These results indicate that TPP-I is required for the partial or complete digestion of certain neuropeptides by brain lysosomes. In the absence of TPP-I, neuropeptides or their degradation products will accumulate in brain lysosomes and may contribute to the pathogenesis of CLN2. Other tissues are spared because they express another peptidase, DPP-I, which has extensive activity on peptides and can compensate for the loss of TPP-I.

The treatment of diabetes mellitus of patients with chronic liver disease.

PubMed

García-Compeán, Diego; González-González, José A; Lavalle-González, Fernando J; González-Moreno, Emmanuel I; Maldonado-Garza, Héctor J; Villarreal-Pérez, Jesús Zacarías

2015-01-01

About 80% of patients with liver cirrhosis may have glucose metabolism disorders, 30% show overt diabetes mellitus (DM). Prospective studies have demonstrated that DM is associated with an increased risk of hepatic complications and death in patients with liver cirrhosis. DM might contribute to liver damage by promoting inflammation and fibrosis through an increase in mitochondrial oxidative stress mediated by adipokines. Based on the above mentioned the effective control of hyperglycemia may have a favorable impact on the evolution of these patients. However, only few therapeutic studies have evaluated the effectiveness and safety of antidiabetic drugs and the impact of the treatment of DM on morbidity and mortality in patients with liver cirrhosis. In addition, oral hypoglycemic agents and insulin may produce hypoglycemia and lactic acidosis, as most of these agents are metabolized by the liver. This review discusses the clinical implications of DM in patients with chronic liver disease. In addition the effectiveness and safety of old, but particularly the new antidiabetic drugs will be described based on pharmacokinetic studies and chronic administration to patients. Recent reports regarding the use of the SGLT2 inhibitors as well as the new incretin-based therapies such as injectable glucagon-like peptide-1 (GLP-1) receptor agonists and oral inhibitors of dipeptidylpeptidase-4 (DPP-4) will be discussed. The establishment of clear guidelines for the management of diabetes in patients with CLD is strongly required.

A randomized, placebo-controlled, double-blind, prospective trial to evaluate the effect of vildagliptin in new-onset diabetes mellitus after kidney transplantation.

PubMed

Haidinger, Michael; Werzowa, Johannes; Voigt, Hans-Christian; Pleiner, Johannes; Stemer, Gunar; Hecking, Manfred; Döller, Dominik; Hörl, Walter H; Weichhart, Thomas; Säemann, Marcus D

2010-10-06

New-onset diabetes mellitus after transplantation (NODAT), a frequent and serious complication after transplantation, is associated with decreased graft and patient survival. Currently, it is diagnosed and treated primarily according to existing guidelines for type II diabetes. To date, only a few trials have studied antidiabetic drugs in patients with NODAT. Vildagliptin is a novel dipeptidyl peptidase-4 (DPP-4) inhibitor that improves pancreatic islet function by enhancing both α- and β-cell responsiveness to increased blood glucose. Experimental data show potential protective effects of DPP-4 inhibitors on islet function after exogenous stress stimuli including immunosuppressants. Therefore, the therapy of NODAT with this class of compounds seems attractive. At present, vildagliptin is used to treat type II diabetes as monotherapy or in combination with other antidiabetic drugs, since that it efficiently decreases glycated hemoglobin (HbA1c) values. Additionally, vildagliptin has been shown to be safe in patients with moderately impaired kidney function. This study will evaluate the safety and efficacy of vildagliptin monotherapy in renal transplant recipients with recently diagnosed NODAT. This study is a randomized, placebo-controlled, double-blind, prospective phase II trial. Using the results of routinely performed oral glucose tolerance tests (OGTT) in stable renal transplant patients at our center, we will recruit patients without a history of diabetes and a 2 h glucose value surpassing 200 mg/dl (11.1 mmol/l). They are randomized to receive either 50 mg vildagliptin or placebo once daily. A total of 32 patients with newly diagnosed NODAT will be included. The primary endpoint is the difference in the 2 h glucose value between baseline and the repeated OGTT performed 3 months after treatment start, compared between the vildagliptin- and the placebo-group. Secondary endpoints include changes in HbA1c and fasting plasma glucose (FPG). The safety of vildagliptin in renal transplant patients will be assessed by the number of symptomatic hypoglycemic episodes (glucose <72 mg/dl or 4 mmol/l), the number of adverse events, and possible medication-associated side-effects. NODAT is a severe complication after kidney transplantation. Few trials have assessed the safety and efficacy of antidiabetic drugs for these patients. The purpose of this study is to assess the safety and efficacy of vildagliptin in renal transplant patients with NODAT. ClinicalTrials.gov NCT00980356.

Incorporation of DPP6a and DPP6K variants in ternary Kv4 channel complex reconstitutes properties of A-type K current in rat cerebellar granule cells.

PubMed

Jerng, Henry H; Pfaffinger, Paul J

2012-01-01

Dipeptidyl peptidase-like protein 6 (DPP6) proteins co-assemble with Kv4 channel α-subunits and Kv channel-interacting proteins (KChIPs) to form channel protein complexes underlying neuronal somatodendritic A-type potassium current (I(SA)). DPP6 proteins are expressed as N-terminal variants (DPP6a, DPP6K, DPP6S, DPP6L) that result from alternative mRNA initiation and exhibit overlapping expression patterns. Here, we study the role DPP6 variants play in shaping the functional properties of I(SA) found in cerebellar granule (CG) cells using quantitative RT-PCR and voltage-clamp recordings of whole-cell currents from reconstituted channel complexes and native I(SA) channels. Differential expression of DPP6 variants was detected in rat CG cells, with DPP6K (41 ± 3%)>DPP6a (33 ± 3%)>DPP6S (18 ± 2%)>DPP6L (8 ± 3%). To better understand how DPP6 variants shape native neuronal I(SA), we focused on studying interactions between the two dominant variants, DPP6K and DPP6a. Although previous studies did not identify unique functional effects of DPP6K, we find that the unique N-terminus of DPP6K modulates the effects of KChIP proteins, slowing recovery and producing a negative shift in the steady-state inactivation curve. By contrast, DPP6a uses its distinct N-terminus to directly confer rapid N-type inactivation independently of KChIP3a. When DPP6a and DPP6K are co-expressed in ratios similar to those found in CG cells, their distinct effects compete in modulating channel function. The more rapid inactivation from DPP6a dominates during strong depolarization; however, DPP6K produces a negative shift in the steady-state inactivation curve and introduces a slow phase of recovery from inactivation. A direct comparison to the native CG cell I(SA) shows that these mixed effects are present in the native channels. Our results support the hypothesis that the precise expression and co-assembly of different auxiliary subunit variants are important factors in shaping the I(SA) functional properties in specific neuronal populations.

Strong Association between Plasma Dipeptidyl Peptidase-4 Activity and Impaired Cognitive Function in Elderly Population with Normal Glucose Tolerance.

PubMed

Chen, Bo; Zheng, Tianpeng; Qin, Linyuan; Hu, Xueping; Zhang, Xiaoxi; Liu, Yihong; Liu, Hongbo; Qin, Shenghua; Li, Gang; Li, Qinghua

2017-01-01

Objective: Inflammation, oxidative stress, and decreased glucagon-like peptide-1 (GLP-1) are risk factors for cognitive impairment. Dipeptidyl peptidase-4 (DPP4) was identified as a novel adipokine capable of enhancing these risk factors. Hence, we investigated the relationship between plasma DPP4 activity and impaired cognitive function in elderly Chinese population with normal glucose tolerance (NGT). Methods: We performed a cross-sectional study using data from 1229 elderly participants (60 years or older) in Guilin. Plasma DPP4 activity, oxidative stress parameters, fasting active GLP-1, and inflammatory markers were measured in all participants. Impaired cognitive function was diagnosed according to the National Institute on Aging-Alzheimer's Association workgroups criteria. Results: Participants in the upper quartile of plasma DPP4 activity had higher C-reactive protein (CRP), interleukin-6 (IL-6), 8-iso-PGF2a, nitrotyrosine, and lower GLP-1 and Montreal Cognitive Assessment (MoCA) scores compared with those in the lowest quartile ( P < 0.001). The odds ratios (ORs) for increased CRP, IL-6, 8-iso-PGF2a, nitrotyrosine, and decreased active GLP-1 were higher with increasing DPP4 quartiles after adjustment for confounders (all P < 0.001). In the highest DPP4 quartile, impaired cognitive function risk was higher (OR, 2.26; 95% confidence interval, 1.36-3.76) than in the lowest quartile after adjustment for potential confounders. The risk for impaired cognitive function increased more with higher levels of DPP4 activity, nitrotyrosine and 8-iso-PGF2a ( P < 0.05), but not with higher IL-6, CRP or lower GLP-1. Conclusion: Plasma DPP4 activity is significantly and independently associated with impaired cognitive function, mainly executive, in elderly Chinese population with NGT. The underlying mechanisms for this association may be partly attributed to the effect of DPP4 on oxidative stress. Plasma DPP4 activity might serve as a risk biomarker or therapeutic target for the prevention and treatment of impaired cognitive function.

Identification of Dipeptidyl-Peptidase (DPP)5 and DPP7 in Porphyromonas endodontalis, Distinct from Those in Porphyromonas gingivalis.

PubMed

Nishimata, Haruka; Ohara-Nemoto, Yuko; Baba, Tomomi T; Hoshino, Tomonori; Fujiwara, Taku; Shimoyama, Yu; Kimura, Shigenobu; Nemoto, Takayuki K

2014-01-01

Dipeptidyl peptidases (DPPs) that liberate dipeptides from the N-terminal end of oligopeptides are crucial for the growth of Porphyromonas species, anaerobic asaccharolytic gram negative rods that utilize amino acids as energy sources. Porphyromonas endodontalis is a causative agent of periapical lesions with acute symptoms and Asp/Glu-specific DPP11 has been solely characterized in this organism. In this study, we identified and characterized two P. endodontalis DPPs, DPP5 and DPP7. Cell-associated DPP activity toward Lys-Ala-4-methylcoumaryl-7-amide (MCA) was prominent in P. endodontalis ATCC 35406 as compared with the Porphyromonas gingivalis strains ATCC 33277, 16-1, HW24D1, ATCC 49417, W83, W50, and HNA99. The level of hydrolysis of Leu-Asp-MCA by DPP11, Gly-Pro-MCA by DPP4, and Met-Leu-MCA was also higher than in the P. gingivalis strains. MER236725 and MER278904 are P. endodontalis proteins belong to the S9- and S46-family peptidases, respectively. Recombinant MER236725 exhibited enzymatic properties including substrate specificity, and salt- and pH-dependence similar to P. gingivalis DPP5 belonging to the S9 family. However, the kcat/Km figure (194 µM-1·sec-1) for the most potent substrate (Lys-Ala-MCA) was 18.4-fold higher as compared to the P. gingivalis entity (10.5 µM-1·sec-1). In addition, P. endodontalis DPP5 mRNA and protein contents were increased several fold as compared with those in P. gingivalis. Recombinant MER278904 preferentially hydrolyzed Met-Leu-MCA and exhibited a substrate specificity similar to P. gingivalis DPP7 belonging to the S46 family. In accord with the deduced molecular mass of 818 amino acids, a 105-kDa band was immunologically detected, indicating that P. endodontalis DPP7 is an exceptionally large molecule in the DPP7/DPP11/S46 peptidase family. The enhancement of four DPP activities was conclusively demonstrated in P. endodontalis, and remarkable Lys-Ala-MCA-hydrolysis was achieved by qualitative and quantitative potentiation of the DPP5 molecule.

Identification of Dipeptidyl-Peptidase (DPP)5 and DPP7 in Porphyromonas endodontalis, Distinct from Those in Porphyromonas gingivalis

PubMed Central

Nishimata, Haruka; Ohara-Nemoto, Yuko; Baba, Tomomi T.; Hoshino, Tomonori; Fujiwara, Taku; Shimoyama, Yu; Kimura, Shigenobu; Nemoto, Takayuki K.

2014-01-01

Dipeptidyl peptidases (DPPs) that liberate dipeptides from the N-terminal end of oligopeptides are crucial for the growth of Porphyromonas species, anaerobic asaccharolytic gram negative rods that utilize amino acids as energy sources. Porphyromonas endodontalis is a causative agent of periapical lesions with acute symptoms and Asp/Glu-specific DPP11 has been solely characterized in this organism. In this study, we identified and characterized two P. endodontalis DPPs, DPP5 and DPP7. Cell-associated DPP activity toward Lys-Ala-4-methylcoumaryl-7-amide (MCA) was prominent in P. endodontalis ATCC 35406 as compared with the Porphyromonas gingivalis strains ATCC 33277, 16-1, HW24D1, ATCC 49417, W83, W50, and HNA99. The level of hydrolysis of Leu-Asp-MCA by DPP11, Gly-Pro-MCA by DPP4, and Met-Leu-MCA was also higher than in the P. gingivalis strains. MER236725 and MER278904 are P. endodontalis proteins belong to the S9- and S46-family peptidases, respectively. Recombinant MER236725 exhibited enzymatic properties including substrate specificity, and salt- and pH-dependence similar to P. gingivalis DPP5 belonging to the S9 family. However, the k cat/K m figure (194 µM−1·sec−1) for the most potent substrate (Lys-Ala-MCA) was 18.4-fold higher as compared to the P. gingivalis entity (10.5 µM−1·sec−1). In addition, P. endodontalis DPP5 mRNA and protein contents were increased several fold as compared with those in P. gingivalis. Recombinant MER278904 preferentially hydrolyzed Met-Leu-MCA and exhibited a substrate specificity similar to P. gingivalis DPP7 belonging to the S46 family. In accord with the deduced molecular mass of 818 amino acids, a 105-kDa band was immunologically detected, indicating that P. endodontalis DPP7 is an exceptionally large molecule in the DPP7/DPP11/S46 peptidase family. The enhancement of four DPP activities was conclusively demonstrated in P. endodontalis, and remarkable Lys-Ala-MCA-hydrolysis was achieved by qualitative and quantitative potentiation of the DPP5 molecule. PMID:25494328

Novel N-substituted aminobenzamide scaffold derivatives targeting the dipeptidyl peptidase-IV enzyme.

PubMed

Al-Balas, Qosay A; Sowaileh, Munia F; Hassan, Mohammad A; Qandil, Amjad M; Alzoubi, Karem H; Mhaidat, Nizar M; Almaaytah, Ammar M; Khabour, Omar F

2014-01-01

The dipeptidyl peptidase-IV (DPP-IV) enzyme is considered a pivotal target for controlling normal blood sugar levels in the body. Incretins secreted in response to ingestion of meals enhance insulin release to the blood, and DPP-IV inactivates these incretins within a short period and stops their action. Inhibition of this enzyme escalates the action of incretins and induces more insulin to achieve better glucose control in diabetic patients. Thus, inhibition of this enzyme will lead to better control of blood sugar levels. In this study, computer-aided drug design was used to help establish a novel N-substituted aminobenzamide scaffold as a potential inhibitor of DPP-IV. CDOCKER software available from Discovery Studio 3.5 was used to evaluate a series of designed compounds and assess their mode of binding to the active site of the DPP-IV enzyme. The designed compounds were synthesized and tested against a DPP-IV enzyme kit provided by Enzo Life Sciences. The synthesized compounds were characterized using proton and carbon nuclear magnetic resonance, mass spectrometry, infrared spectroscopy, and determination of melting point. Sixty-nine novel compounds having an N-aminobenzamide scaffold were prepared, with full characterization. Ten of these compounds showed more in vitro activity against DPP-IV than the reference compounds, with the most active compounds scoring 38% activity at 100 μM concentration. The N-aminobenzamide scaffold was shown in this study to be a valid scaffold for inhibiting the DPP-IV enzyme. Continuing work could unravel more active compounds possessing the same scaffold.

Increased plasma DPP4 activities predict new-onset atherosclerosis in association with its proinflammatory effects in Chinese over a four year period: A prospective study.

PubMed

Zheng, T P; Yang, F; Gao, Y; Baskota, A; Chen, T; Tian, H M; Ran, X W

2014-08-01

DPP4, a novel proinflammatory cytokine, is involved in the inflammatory process through its interaction with IGF-II/M6P receptor. We aimed to investigate whether it could predict new-onset atherosclerosis in Chinese. A prospective study was conducted of 590 adults (213 men and 377 women) aged 18-70 years without atherosclerosis examined in 2007(baseline) and 2011(follow-up). Circulating DPP4 activity, inflammatory markers, IGF-II/M6P receptor and common carotid artery Intima-Media Thickness (C-IMT) were measured at baseline and four years later. At baseline, individuals in the highest quartile of DPP4 activity had higher age, WHR, BMI, SBP, fasting insulin, 2h-PG, TG, LDL-C, IL-6, hs-CRP, IGF-II/M6P-R, C-IMT and lower HDL-C compared with individuals in the lowest quartile. After a 4-year follow-up, 71 individuals developed atherosclerosis. In multiple linear regression analysis, baseline DPP4 activity was an independent predictor of an increase in inflammatory markers, IGF-II/M6P receptor, and C-IMT over a 4-year period (all P < 0.01). In multivariable-adjusted models, the odds ratio (OR) for incident atherosclerosis comparing the highest with the lowest quartiles of DPP4 activity was 3.17 (95%CI 1.33-7.58) after adjustment for confounding risk factors (P = 0.009). The incidence of atherosclerosis owing to DPP4 activity increased by 12.41%. DPP4 activity is an important predictor of the onset of inflammation and atherosclerosis in apparently healthy Chinese. This finding may have important implications for understanding the proinflammatory role of DPP-4 in the pathogenesis of atherosclerosis. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Synthesis, kinetic evaluation, and utilization of a biotinylated dipeptide proline diphenyl phosphonate for the disclosure of dipeptidyl peptidase IV-like serine proteases.

PubMed

Gilmore, Brendan F; Carson, Louise; McShane, Laura L; Quinn, Derek; Coulter, Wilson A; Walker, Brian

2006-08-18

In this study, we report on the synthesis, kinetic characterisation, and application of a novel biotinylated and active site-directed inactivator of dipeptidyl peptidase IV (DPP-IV). Thus, the dipeptide-derived proline diphenyl phosphonate NH(2)-Glu(biotinyl-PEG)-Pro(P)(OPh)(2) has been prepared by a combination of classical solution- and solid-phase methodologies and has been shown to be an irreversible inhibitor of porcine DPP-IV, exhibiting an over all second-order rate constant (k(i)/K(i)) for inhibition of 1.57 x 10(3) M(-1) min(-1). This value compares favourably with previously reported rates of inactivation of DPP-IV by dipeptides containing a P(1) proline diphenyl phosphonate grouping [B. Boduszek, J. Oleksyszyn, C.M. Kam, J. Selzler, R.E. Smith, J.C. Powers, Dipeptide phophonates as inhibitors of dipeptidyl peptidase IV, J. Med. Chem. 37 (1994) 3969-3976; B.F. Gilmore, J.F. Lynas, C.J. Scott, C. McGoohan, L. Martin, B. Walker, Dipeptide proline diphenyl phosphonates are potent, irreversible inhibitors of seprase (FAPalpha), Biochem, Biophys. Res. Commun. 346 (2006) 436-446.], thus demonstrating that the incorporation of the side-chain modified (N-biotinyl-3-(2-(2-(3-aminopropyloxy)-ethoxy)-ethoxy)-propyl) glutamic acid residue at the P(2) position is compatible with inhibitor efficacy. The utilisation of this probe for the detection of both purified dipeptidyl peptidase IV and the disclosure of a dipeptidyl peptidase IV-like activity from a clinical isolate of Porphyromonas gingivalis, using established electrophoretic and Western blotting techniques previously developed by our group, is also demonstrated.

S-glutathionylation of an auxiliary subunit confers redox sensitivity to Kv4 channel inactivation.

PubMed

Jerng, Henry H; Pfaffinger, Paul J

2014-01-01

Reactive oxygen species (ROS) regulate ion channels, modulate neuronal excitability, and contribute to the etiology of neurodegenerative disorders. ROS differentially suppress fast "ball-and-chain" N-type inactivation of cloned Kv1 and Kv3 potassium channels but not of Kv4 channels, likely due to a lack of reactive cysteines in Kv4 N-termini. Recently, we discovered that N-type inactivation of Kv4 channel complexes can be independently conferred by certain N-terminal variants of Kv4 auxiliary subunits (DPP6a, DPP10a). Here, we report that both DPP6a and DPP10a, like Kv subunits with redox-sensitive N-type inactivation, contain a highly conserved cysteine in their N-termini (Cys-13). To test if N-type inactivation mediated by DPP6a or DPP10a is redox sensitive, Xenopus oocyte recordings were performed to examine the effects of two common oxidants, tert-butyl hydroperoxide (tBHP) and diamide. Both oxidants markedly modulate DPP6a- or DPP10a-conferred N-type inactivation of Kv4 channels, slowing the overall inactivation and increasing the peak current. These functional effects are fully reversed by the reducing agent dithiothreitol (DTT) and appear to be due to a selective modulation of the N-type inactivation mediated by these auxiliary subunits. Mutation of DPP6a Cys-13 to serine eliminated the tBHP or diamide effects, confirming the importance of Cys-13 to the oxidative regulation. Biochemical studies designed to elucidate the underlying molecular mechanism show no evidence of protein-protein disulfide linkage formation following cysteine oxidation. Instead, using a biotinylated glutathione (BioGEE) reagent, we discovered that oxidation by tBHP or diamide leads to S-glutathionylation of Cys-13, suggesting that S-glutathionylation underlies the regulation of fast N-type inactivation by redox. In conclusion, our studies suggest that Kv4-based A-type current in neurons may show differential redox sensitivity depending on whether DPP6a or DPP10a is highly expressed, and that the S-glutathionylation mechanism may play a previously unappreciated role in mediating excitability changes and neuropathologies associated with ROS.

Vildagliptin ameliorates pulmonary fibrosis in lipopolysaccharide-induced lung injury by inhibiting endothelial-to-mesenchymal transition.

PubMed

Suzuki, Toshio; Tada, Yuji; Gladson, Santhi; Nishimura, Rintaro; Shimomura, Iwao; Karasawa, Satoshi; Tatsumi, Koichiro; West, James

2017-10-16

Pulmonary fibrosis is a late manifestation of acute respiratory distress syndrome (ARDS). Sepsis is a major cause of ARDS, and its pathogenesis includes endotoxin-induced vascular injury. Recently, endothelial-to-mesenchymal transition (EndMT) was shown to play an important role in pulmonary fibrosis. On the other hand, dipeptidyl peptidase (DPP)-4 was reported to improve vascular dysfunction in an experimental sepsis model, although whether DPP-4 affects EndMT and fibrosis initiation during lipopolysaccharide (LPS)-induced lung injury is unclear. The aim of this study was to investigate the anti-EndMT effects of the DPP-4 inhibitor vildagliptin in pulmonary fibrosis after systemic endotoxemic injury. A septic lung injury model was established by intraperitoneal injection of lipopolysaccharide (LPS) in eight-week-old male mice (5 mg/kg for five consecutive days). The mice were then treated with vehicle or vildagliptin (intraperitoneally, 10 mg/kg, once daily for 14 consecutive days from 1 day before the first administration of LPS.). Flow cytometry, immunohistochemical staining, and quantitative polymerase chain reaction (qPCR) analysis was used to assess cell dynamics and EndMT function in lung samples from the mice. Lung tissue samples from treated mice revealed obvious inflammatory reactions and typical interstitial fibrosis 2 days and 28 days after LPS challenge. Quantitative flow cytometric analysis showed that the number of pulmonary vascular endothelial cells (PVECs) expressing alpha-smooth muscle actin (α-SMA) or S100 calcium-binding protein A4 (S100A4) increased 28 days after LPS challenge. Similar increases in expression were also confirmed by qPCR of mRNA from isolated PVECs. EndMT cells had higher proliferative activity and migration activity than mesenchymal cells. All of these changes were alleviated by intraperitoneal injection of vildagliptin. Interestingly, vildagliptin and linagliptin significantly attenuated EndMT in the absence of immune cells or GLP-1. Inhibiting DPP-4 signaling by vildagliptin could ameliorate pulmonary fibrosis by downregulating EndMT in systemic LPS-induced lung injury.

Factors Associated with Type 2 Diabetes Mellitus Treatment Choice Across Four European Countries.

PubMed

Heintjes, Edith M; Overbeek, Jetty A; Hall, Gillian C; Prieto-Alhambra, Daniel; Lapi, Francesco; Hammar, Niklas; Bezemer, Irene D

2017-11-01

The aim of this analysis was to identify factors associated with the choice of type 2 diabetes mellitus (T2DM) therapy at the time of intensification of antidiabetic treatment across 4 European countries. Antidiabetic drug prescription/dispensing records and patients' characteristics were obtained from the electronic health care records of patients with T2DM from the Netherlands (NL), Italy, and Spain (ES) (all, 2007-2011); and the United Kingdom (UK; 2008-2012). Oral monotherapy was defined as first-line; oral dual therapy, as second-line; >2 oral treatments or oral combined with an injectable, as third-line; and injectables only, as fourth-line treatment. Treatment intensification was defined as the start of a higher line of treatment. Comedication, comorbidities, clinical parameters, and other factors associated with treatment choice were identified using multivariate relative risk estimation by Poisson regression with robust error variance. In the 5-year study period, 485,120 patients (79% of the treated T2DM population) underwent treatment intensification. Changes in treatment choice were clearly visible over the study period, such as a decline in the use of thiazolidinediones (NL, ES, UK) and increases in the use of dipeptidyl peptidase-4 inhibitors (DPP4i) (NL, ES, UK) and glucagon-like peptide-1 receptor agonists (UK). With first-line treatment, advanced age and renal comorbidity were associated with the use of sulfonylureas (SUs; all countries), whereas high body mass index (BMI) was inversely associated with SU use in the United Kingdom and Spain. With second-line treatment, advanced age was associated with metformin + SU use (all countries); and renal comorbidity with SU + DPP4i use in the United Kingdom and the Netherlands. High BMI was associated with metformin + thiazolidinedione (TZD) use in the United Kingdom and Spain, and with metformin + DPP4i in the United Kingdom. With third-line treatment, advanced age and renal comorbidity were associated with the use of SU + insulin (NL, ES, UK). Hemoglobin A 1c >8.5% was positively associated, and high BMI was inversely associated, with the use of any third-line combination containing insulin. Across treatment lines TZD and metformin were negatively associated with renal and cardiac morbidity. Second and third line treatment choices strongly depended on prior treatments. With fourth-line treatment, women were more likely to receive glucagon-like peptide-1 receptor agonists than were men in the United Kingdom and Spain. The results suggest that the main factors driving treatment choice at any stage of intensification were age, hemoglobin A 1c , BMI, renal and cardiac morbidity, and treatment history. These drivers were consistent with guidelines on, and contraindications of, specific medications. Differences between countries were generally consistent with, but not solely attributable to, differences in local guidelines and reimbursement policies. Copyright © 2017 Elsevier HS Journals, Inc. All rights reserved.

Unique Cardiac Purkinje Fiber Transient Outward Current β-Subunit Composition

PubMed Central

Xiao, Ling; Koopmann, Tamara T.; Ördög, Balázs; Postema, Pieter G.; Verkerk, Arie O.; Iyer, Vivek; Sampson, Kevin J.; Boink, Gerard J.J.; Mamarbachi, Maya A.; Varro, Andras; Jordaens, Luc; Res, Jan; Kass, Robert S.; Wilde, Arthur A.; Bezzina, C.R.; Nattel, Stanley

2015-01-01

Rationale A chromosomal haplotype producing cardiac overexpression of dipeptidyl peptidase-like protein-6 (DPP6) causes familial idiopathic ventricular fibrillation. The molecular basis of transient outward current (Ito) in Purkinje fibers (PFs) is poorly understood. We hypothesized that DPP6 contributes to PF Ito and that its overexpression might specifically alter PF Ito properties and repolarization. Objective To assess the potential role of DPP6 in PF Ito. Methods and Results Clinical data in 5 idiopathic ventricular fibrillation patients suggested arrhythmia origin in the PF-conducting system. PF and ventricular muscle Ito had similar density, but PF Ito differed from ventricular muscle in having tetraethylammonium sensitivity and slower recovery. DPP6 overexpression significantly increased, whereas DPP6 knockdown reduced, Ito density and tetraethylammonium sensitivity in canine PF but not in ventricular muscle cells. The K+-channel interacting β-subunit K+-channel interacting protein type-2, essential for normal expression of Ito in ventricular muscle, was weakly expressed in human PFs, whereas DPP6 and frequenin (neuronal calcium sensor-1) were enriched. Heterologous expression of Kv4.3 in Chinese hamster ovary cells produced small Ito; Ito amplitude was greatly enhanced by coexpression with K+-channel interacting protein type-2 or DPP6. Coexpression of DPP6 with Kv4.3 and K+-channel interacting protein type-2 failed to alter Ito compared with Kv4.3/K+-channel interacting protein type-2 alone, but DPP6 expression with Kv4.3 and neuronal calcium sensor-1 (to mimic PF Ito composition) greatly enhanced Ito compared with Kv4.3/neuronal calcium sensor-1 and recapitulated characteristic PF kinetic/pharmacological properties. A mathematical model of cardiac PF action potentials showed that Ito enhancement can greatly accelerate PF repolarization. Conclusions These results point to a previously unknown central role of DPP6 in PF Ito, with DPP6 gain of function selectively enhancing PF current, and suggest that a DPP6-mediated PF early-repolarization syndrome might be a novel molecular paradigm for some forms of idiopathic ventricular fibrillation. PMID:23532596

Effects of Crystal Morphology on Singlet Exciton Fission in Diketopyrrolopyrrole Thin Films.

PubMed

Hartnett, Patrick E; Margulies, Eric A; Mauck, Catherine M; Miller, Stephen A; Wu, Yilei; Wu, Yi-Lin; Marks, Tobin J; Wasielewski, Michael R

2016-02-25

Singlet exciton fission (SF) is a promising strategy for increasing photovoltaic efficiency, but in order for SF to be useful in solar cells, it should take place in a chromophore that is air-stable, highly absorptive, solution processable, and inexpensive. Unlike many SF chromophores, diketopyrrolopyrrole (DPP) conforms to these criteria, and here we investigate SF in DPP for the first time. SF yields in thin films of DPP derivatives, which are widely used in organic electronics and photovoltaics, are shown to depend critically on crystal morphology. Time-resolved spectroscopy of three DPP derivatives with phenyl (3,6-diphenylpyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione, PhDPP), thienyl (3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione, TDPP), and phenylthienyl (3,6-di(5-phenylthiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione, PhTDPP) aromatic substituents in 100-200 nm thin films reveals that efficient SF occurs only in TDPP and PhTDPP (τSF = 220 ± 20 ps), despite the fact that SF is most exoergic in PhDPP. This result correlates well with the greater degree of π-overlap and closer π-stacking in TDPP (3.50 Å) and PhTDPP (3.59 Å) relative to PhDPP (3.90 Å) and demonstrates that SF in DPP is highly sensitive to the electronic coupling between adjacent chromophores. The triplet yield in PhTDPP films is determined to be 210 ± 35% by the singlet depletion method and 165 ± 30% by the energy transfer method, showing that SF is nearly quantitative in these films and that DPP derivatives are a promising class of SF chromophores for enhancing photovoltaic performance.

Entropy-driven binding of opioid peptides induces a large domain motion in human dipeptidyl peptidase III

PubMed Central

Bezerra, Gustavo A.; Dobrovetsky, Elena; Viertlmayr, Roland; Dong, Aiping; Binter, Alexandra; Abramić, Marija; Macheroux, Peter; Dhe-Paganon, Sirano; Gruber, Karl

2012-01-01

Opioid peptides are involved in various essential physiological processes, most notably nociception. Dipeptidyl peptidase III (DPP III) is one of the most important enkephalin-degrading enzymes associated with the mammalian pain modulatory system. Here we describe the X-ray structures of human DPP III and its complex with the opioid peptide tynorphin, which rationalize the enzyme's substrate specificity and reveal an exceptionally large domain motion upon ligand binding. Microcalorimetric analyses point at an entropy-dominated process, with the release of water molecules from the binding cleft (“entropy reservoir”) as the major thermodynamic driving force. Our results provide the basis for the design of specific inhibitors that enable the elucidation of the exact role of DPP III and the exploration of its potential as a target of pain intervention strategies. PMID:22493238

Biocatalytic ammonolysis of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester: preparation of an intermediate to the dipeptidyl peptidase IV inhibitor Saxagliptin.

PubMed

Gill, Iqbal; Patel, Ramesh

2006-02-01

An efficient biocatalytic method has been developed for the conversion of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester (1) into the corresponding amide (5S)-5-aminocarbonyl-4,5-dihydro-1H-pyrrole-1-carboxylic acid, 1-(1,1-dimethylethyl)ester (2), which is a critical intermediate in the synthesis of the dipeptidyl peptidase IV (DPP4) inhibitor Saxagliptin (3). Candida antartica lipase B mediates ammonolysis of the ester with ammonium carbamate as ammonia donor to yield up to 71% of the amide. The inclusion of Ascarite and calcium chloride as adsorbents for carbon dioxide and ethanol byproducts, respectively, increases the yield to 98%, thereby offering an efficient and practical alternative to chemical routes which yield 57-64%.

Dipeptidyl peptidase IV (DPP-IV) inhibition prevents fibrosis in adipose tissue of obese mice.

PubMed

Marques, Ana Patrícia; Cunha-Santos, Janete; Leal, Helena; Sousa-Ferreira, Lígia; Pereira de Almeida, Luís; Cavadas, Cláudia; Rosmaninho-Salgado, Joana

2018-03-01

During the development of obesity the expansion of white adipose tissue (WAT) leads to a dysregulation and an excessive remodeling of extracellular matrix (ECM), leading to fibrosis formation. These ECM changes have high impact on WAT physiology and may change obesity progression. Blocking WAT fibrosis may have beneficial effects on the efficacy of diet regimen or therapeutical approaches in obesity. Since dipeptidyl peptidase IV (DPP-IV) inhibitors prevent fibrosis in tissues, such as heart, liver and kidney, the objective of this study was to assess whether vildagliptin, a DPP-IV inhibitor, prevents fibrosis in WAT in a mouse model of obesity, and to investigate the mechanisms underlying this effect. We evaluated the inhibitory effect of vildagliptin on fibrosis markers on WAT of high-fat diet (HFD)-induced obese mice and on 3T3-L1 cell line of mouse adipocytes treated with a fibrosis inducer, transforming growth factor beta 1 (TGFβ1). Vildagliptin prevents the increase of fibrosis markers in WAT of HFD-fed mice and reduces blood glucose, serum triglycerides, total cholesterol and leptin levels. In the in vitro study, the inhibition of DPP-IV with vildagliptin, neuropeptide Y (NPY) treatment and NPY Y 1 receptor activation prevents ECM deposition and fibrosis markers increase induced by TGFβ1 treatment. Vildagliptin prevents fibrosis formation in adipose tissue in obese mice, at least partially through NPY and NPY Y 1 receptor activation. This study highlights the importance of vildagliptin in the treatment of fibrosis that occur in obesity. Copyright © 2017 Elsevier B.V. All rights reserved.

DPP8 and DPP9 inhibition induces pro-caspase-1-dependent monocyte and macrophage pyroptosis.

PubMed

Okondo, Marian C; Johnson, Darren C; Sridharan, Ramya; Go, Eun Bin; Chui, Ashley J; Wang, Mitchell S; Poplawski, Sarah E; Wu, Wengen; Liu, Yuxin; Lai, Jack H; Sanford, David G; Arciprete, Michael O; Golub, Todd R; Bachovchin, William W; Bachovchin, Daniel A

2017-01-01

Val-boroPro (Talabostat, PT-100), a nonselective inhibitor of post-proline cleaving serine proteases, stimulates mammalian immune systems through an unknown mechanism of action. Despite this lack of mechanistic understanding, Val-boroPro has attracted substantial interest as a potential anticancer agent, reaching phase 3 trials in humans. Here we show that Val-boroPro stimulates the immune system by triggering a proinflammatory form of cell death in monocytes and macrophages known as pyroptosis. We demonstrate that the inhibition of two serine proteases, DPP8 and DPP9, activates the pro-protein form of caspase-1 independent of the inflammasome adaptor ASC. Activated pro-caspase-1 does not efficiently process itself or IL-1β but does cleave and activate gasdermin D to induce pyroptosis. Mice lacking caspase-1 do not show immune stimulation after treatment with Val-boroPro. Our data identify what is to our knowledge the first small molecule that induces pyroptosis and reveals a new checkpoint that controls the activation of the innate immune system.

Localized expression of a dpp/BMP2/4 ortholog in a coral embryo

PubMed Central

Hayward, David C.; Samuel, Gabrielle; Pontynen, Patricia C.; Catmull, Julian; Saint, Robert; Miller, David J.; Ball, Eldon E.

2002-01-01

As the closest outgroup to the Bilateria, the Phylum Cnidaria is likely to be critical to understanding the origins and evolution of body axes. Proteins of the decapentaplegic (DPP)/bone morphogenetic protein (BMP) 2/4 subfamily are central to the specification of the dorsoventral (D/V) axis in bilateral animals, albeit with an axis inversion between arthropods and chordates. We show that a dpp/BMP2/4 ortholog (bmp2/4-Am) is present in the reef-building scleractinian coral, Acropora millepora (Class Anthozoa) and that it is capable of causing phenotypic effects in Drosophila that mimic those of the endogenous dpp gene. We also show that, during coral embryonic development, bmp2/4-Am expression is localized in an ectodermal region adjacent to the blastopore. Thus, a representative of the DPP/BMP2/4 subfamily of ligands was present in the common ancestor of diploblastic and triploblastic animals where it was probably expressed in a localized fashion during development. A localized source of DPP/BMP2/4 may have already been used in axis formation in this ancestor, or it may have provided a means by which an axis could evolve in triploblastic animals. PMID:12048233

Risk for Hospitalized Heart Failure Among New Users of Saxagliptin, Sitagliptin, and Other Antihyperglycemic Drugs

PubMed Central

Toh, Sengwee; Hampp, Christian; Reichman, Marsha E.; Graham, David J.; Balakrishnan, Suchitra; Pucino, Frank; Hamilton, Jack; Lendle, Samuel; Iyer, Aarthi; Rucker, Malcolm; Pimentel, Madelyn; Nathwani, Neesha; Griffin, Marie R.; Brown, Nancy J.; Fireman, Bruce H.

2016-01-01

Background Recent postmarketing trials produced conflicting results about the risk for hospitalized heart failure (hHF) associated with dipeptidyl peptidase-4 (DPP-4) inhibitors, creating uncertainty about the safety of these antihyperglycemic agents. Objective To examine the associations of hHF with saxagliptin and sitagliptin. Design Population-based, retrospective, new-user cohort study. Setting 18 health insurance and health system data partners in the U.S. Food and Drug Administration’s Mini-Sentinel program. Patients Patients aged 18 years or older with type 2 diabetes who initiated therapy with saxagliptin, sitagliptin, pioglitazone, second-generation sulfonylureas, or long-acting insulin products from 2006 to 2013. Measurements Hospitalized HF, identified by International Classification of Diseases, Ninth Revision, Clinical Modification codes 402.×1, 404.×1, 404.×3, and 428.×× recorded as the principal discharge diagnosis. Results 78 553 saxagliptin users and 298 124 sitagliptin users contributed an average of 7 to 9 months of follow-up data to 1 or more pairwise comparisons. The risk for hHF was not higher with DPP-4 inhibitors than with the other study drugs. The hazard ratios from the disease risk score (DRS)–stratified analyses were 0.83 (95% CI, 0.70 to 0.99) for saxagliptin versus sitagliptin, 0.63 (CI, 0.47 to 0.85) for saxagliptin versus pioglitazone, 0.69 (CI, 0.54 to 0.87) for saxagliptin versus sulfonylureas, and 0.61 (CI, 0.50 to 0.73) for saxagliptin versus insulin. The DRS-stratified hazard ratios were 0.74 (CI, 0.64 to 0.85) for sitagliptin versus pioglitazone, 0.86 (CI, 0.77 to 0.95) for sitagliptin versus sulfonylureas, and 0.71 (CI, 0.64 to 0.78) for sitagliptin versus insulin. Results from the 1:1 propensity score–matched analyses were similar. Results were also similar in subgroups of patients with and without prior cardiovascular disease and in a subgroup defined by the 2 highest DRS deciles. Limitation Residual confounding and short follow-up. Conclusion In this large cohort study, a higher risk for hHF was not observed in users of saxagliptin or sitagliptin compared with other selected antihyperglycemic agents. Primary Funding Source U.S. Food and Drug Administration. PMID:27110660

Increased plasma dipeptidyl peptidase-4 activities are associated with high prevalence of subclinical atherosclerosis in Chinese patients with newly diagnosed type 2 diabetes: a cross-sectional study.

PubMed

Zheng, T P; Liu, Y H; Yang, L X; Qin, S H; Liu, H B

2015-10-01

Hyperglycemia, insulin resistance, dislipidemia, oxidative stress and inflammation are well-documented risk factors for subclinical atherosclerosis. Dipeptidyl peptidase-4(DPP4) is a newly identified adipokine related to these risk factors. Hence, we aimed to investigate the association between plasma DPP4 activities and subclinical atherosclerosis in type 2 diabetes. A total of 985 newly diagnosed type 2 diabetic subjects were studied. Plasma DPP4 activity, mannose 6-phosphate receptor (M6P-R), oxidative stress parameters, inflammatory markers and common carotid artery Intima-Media Thickness (c-IMT) were measured in all participants. Participants in the highest quartile of DPP4 activity had higher HbA1c, homeostatic model assessment of insulin resistance(HOMA-IR), triglyceride, low-density lipoprotein cholesterol(LDL-C), oxidized LDL, nitrotyrosine, 8-iso-PGF2a, interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), M6P-R, c-IMT compared with participants in the lowest quartile (all P < 0.001). DPP4 activities were associated positively with HbA1c, HOMA-IR, triglyceride, LDL-C, oxidized LDL, nitrotyrosine, 8-iso-PGF2a, IL-6, hs-CRP, M6P-R and c-IMT (all P < 0.05). The ORs for insulin resistance, dislipidemia, oxidative stress and inflammation were higher with increasing DPP4 quartiles (P < 0.001 for trend). In the highest DPP4 quartile, subclinical atherosclerosis risk was significantly higher (OR 4.97; 95% CI 3.03-8.17) than in the lowest quartile. This association remained strong (2.17; 1.21-3.89) after further controlling for HbA1c, HOMA-IR, triglyceride, oxidized LDL, nitrotyrosine, and IL-6. This study shows that increased DPP4 activities are positively and independently associated with subclinical atherosclerosis in type 2 diabetes. Our findings suggest of potential role of DPP4 in the pathogenesis of subclinical atherosclerosis and in the prevention and management of this disease. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Type of Resection (Whipple vs. Distal) Does Not Affect the National Failure to Provide Post-resection Adjuvant Chemotherapy in Localized Pancreatic Cancer.

PubMed

Bergquist, John R; Ivanics, Tommy; Shubert, Christopher R; Habermann, Elizabeth B; Smoot, Rory L; Kendrick, Michael L; Nagorney, David M; Farnell, Michael B; Truty, Mark J

2017-06-01

Adjuvant chemotherapy improves survival after curative intent resection for localized pancreatic adenocarcinoma (PDAC). Given the differences in perioperative morbidity, we hypothesized that patients undergoing distal partial pancreatectomy (DPP) would receive adjuvant therapy more often those undergoing pancreatoduodenectomy (PD). The National Cancer Data Base (2004-2012) identified patients with localized PDAC undergoing DPP and PD, excluding neoadjuvant cases, and factors associated with receipt of adjuvant therapy were identified. Overall survival (OS) was analyzed using multivariable Cox proportional hazards regression. Overall, 13,501 patients were included (DPP, n = 1933; PD, n = 11,568). Prognostic characteristics were similar, except DPP patients had fewer N1 lesions, less often positive margins, more minimally invasive resections, and shorter hospital stay. The proportion of patients not receiving adjuvant chemotherapy was equivalent (DPP 33.7%, PD 32.0%; p = 0.148). The type of procedure was not independently associated with adjuvant chemotherapy (hazard ratio 0.96, 95% confidence interval 0.90-1.02; p = 0.150), and patients receiving adjuvant chemotherapy had improved unadjusted and adjusted OS compared with surgery alone. The type of resection did not predict adjusted mortality (p = 0.870). Receipt of adjuvant chemotherapy did not vary by type of resection but improved survival independent of procedure performed. Factors other than type of resection appear to be driving the nationwide rates of post-resection adjuvant chemotherapy in localized PDAC.

Vildagliptin: the evidence for its place in the treatment of type 2 diabetes mellitus

PubMed Central

Profit, Louise; Chrisp, Paul; Nadin, Carole

2008-01-01

Introduction: Type 2 diabetes is increasing in prevalence worldwide and is a leading cause of morbidity and mortality, mainly due to the development of complications. Vildagliptin is an inhibitor of dipeptidyl peptidase 4 (DPP-4), a new class of oral antidiabetic agents. Aims: To evaluate the role of vildagliptin in the management of type 2 diabetes. Evidence review: Clear evidence shows that vildagliptin improves glycemic control (measured by glycosylated hemoglobin and blood glucose levels) more than placebo in adults with type 2 diabetes, either as monotherapy or in combination with metformin. Vildagliptin is as effective as pioglitazone and rosiglitazone, and slightly less effective than metformin, although better tolerated. Further glycemic control is achieved when adding vildagliptin to metformin, pioglitazone, or glimepride. There is evidence that vildagliptin improves beta-cell function and insulin sensitivity. Vildagliptin does not appear to be associated with weight gain or with a higher risk of hypoglycemia than placebo or other commonly used oral antidiabetic agents. Economic evidence is currently lacking. Place in therapy: Vildagliptin improves glycemic control with little if any weight gain or hypoglycemia in adult patients with type 2 diabetes when given alone or in combination with metformin, thiazolidinediones, or sulfonylureas. Since many diabetic patients require combination therapy, the complementary mechanism of action of vildagliptin and other commonly prescribed antidiabetic drugs represents an important new therapeutic option in diabetes management. PMID:20694081

Identification and Characterization of Prokaryotic Dipeptidyl-peptidase 5 from Porphyromonas gingivalis *

PubMed Central

Ohara-Nemoto, Yuko; Rouf, Shakh M. A.; Naito, Mariko; Yanase, Amie; Tetsuo, Fumi; Ono, Toshio; Kobayakawa, Takeshi; Shimoyama, Yu; Kimura, Shigenobu; Nakayama, Koji; Saiki, Keitarou; Konishi, Kiyoshi; Nemoto, Takayuki K.

2014-01-01

Porphyromonas gingivalis, a Gram-negative asaccharolytic anaerobe, is a major causative organism of chronic periodontitis. Because the bacterium utilizes amino acids as energy and carbon sources and incorporates them mainly as dipeptides, a wide variety of dipeptide production processes mediated by dipeptidyl-peptidases (DPPs) should be beneficial for the organism. In the present study, we identified the fourth P. gingivalis enzyme, DPP5. In a dpp4-7-11-disrupted P. gingivalis ATCC 33277, a DPP7-like activity still remained. PGN_0756 possessed an activity indistinguishable from that of the mutant, and was identified as a bacterial orthologue of fungal DPP5, because of its substrate specificity and 28.5% amino acid sequence identity with an Aspergillus fumigatus entity. P. gingivalis DPP5 was composed of 684 amino acids with a molecular mass of 77,453, and existed as a dimer while migrating at 66 kDa on SDS-PAGE. It preferred Ala and hydrophobic residues, had no activity toward Pro at the P1 position, and no preference for hydrophobic P2 residues, showed an optimal pH of 6.7 in the presence of NaCl, demonstrated Km and kcat/Km values for Lys-Ala-MCA of 688 μm and 11.02 μm−1 s−1, respectively, and was localized in the periplasm. DPP5 elaborately complemented DPP7 in liberation of dipeptides with hydrophobic P1 residues. Examinations of DPP- and gingipain gene-disrupted mutants indicated that DPP4, DPP5, DPP7, and DPP11 together with Arg- and Lys-gingipains cooperatively liberate most dipeptides from nutrient oligopeptides. This is the first study to report that DPP5 is expressed not only in eukaryotes, but also widely distributed in bacteria and archaea. PMID:24398682

Combination of Sitagliptin and Silymarin ameliorates liver fibrosis induced by carbon tetrachloride in rats.

PubMed

Sokar, Samia Salem; El-Sayad, Magda El-Sayed; Ghoneim, Mai El-Sayed; Shebl, Abdelhadi Mohamed

2017-05-01

Liver fibrosis is a common pathological condition that occurs in most conditions associated with chronic liver injury. Silymarin is a herbal product widely used for its hepatoprotective effect. Sitagliptin, a dipeptidyl peptidase-4 inhibitor (DPP4-I), is clinically used as an oral antidiabetic agent. This study was designed to investigate the effects of Sitagliptin, Silymarin, and their combination on established liver fibrosis in carbon tetrachloride (CCl 4 ) rat model. Male albino rats received intraperitoneal injections of CCl 4 three times a week for 7 weeks, as well as daily oral treatments of Sitagliptin (100mg/kg) or Silymarin (100mg/kg) or their combination during the 7 weeks of intoxication. Hepatic fibrotic changes were evaluated by measuring hepatic enzymes (ALT, AST, ALP, and GGT) and markers of fibrosis (transforming growth factor β1 (TGF-β1), tissue 4-hydroxyproline level, histopathological score), oxidative stress (MDA, GSH, and NOx levels), inflammation (interleukin-6) as well as markers of HSCs activation (α-smooth muscle actin (α-SMA) expression). The injected rats with CCl 4 for 7 weeks resulted in a marked elevation of hepatic fibrotic changes and reduction of GSH level, while the combination therapy showed a significant decrease in the former one and a significant increase in the later. In conclusion, this study shows that the combination therapy is more beneficial than monotherapy in ameliorating liver fibrosis in rats. Our findings suggest that Sitagliptin alone or in combination with Silymarin may introduce a new strategy for treating liver fibrosis in humans. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The serum level of soluble CD26/dipeptidyl peptidase 4 increases in response to acute hyperglycemia after an oral glucose load in healthy subjects: association with high-molecular weight adiponectin and hepatic enzymes.

PubMed

Aso, Yoshimasa; Terasawa, Tomoko; Kato, Kanako; Jojima, Teruo; Suzuki, Kunihiro; Iijima, Toshie; Kawagoe, Yoshiaki; Mikami, Shigeru; Kubota, Yoshiro; Inukai, Toshihiko; Kasai, Kikuo

2013-11-01

A soluble form of CD26/dipeptidyl peptidase 4 (sCD26/DPP4) is found in serum and it has DPP4 enzymatic activity. We investigated whether the serum level of sCD26/DPP4 was influenced by the oral glucose tolerance test (OGTT) in healthy subjects. The serum sCD26/DPP4 level increased significantly from 824.5 ng/mL (interquartile range, from 699.0 to 1050 ng/mL) at baseline to a peak of 985.0 ng/mL (interquartile range, from 796.5 to 1215 ng/mL) during the OGTT (P < 0.0001). The peak sCD26/DPP4 level correlated positively with the baseline age and body mass index, and fasting plasma glucose (FPG), homeostasis model assessment of insulin resistance (HOMA-IR), triglycerides (TG), alanine aminotransferase, and γ-glutamyl transpeptidase (GGT) levels whereas it correlated negatively with high-density lipoprotein (HDL) cholesterol and the serum levels of total and high-molecular weight (HMW) adiponectin. Stepwise regression analysis was done with forward selection of variables, including age, FPG, HOMA-IR, TG, HDL cholesterol, uric acid, GGT, C-reactive protein, and HMW adiponectin. In a model that explained 57.5% of the variation of the peak sCD26/DPP4 level, GGT (β = 0.382, P = 0.007) and HOMA-IR (β = 0.307, P = 0.034) were independent determinants of the peak serum level of sCD26/DPP4. Serum HMW adiponectin decreased significantly from 4.43 μg/mL (interquartile range, from 2.80 to 6.65 μg/mL) at baseline to 4.17 μg/mL (interquartile range, from 2.48 to 6.96 μg/mL) 120 minutes after the oral glucose load (P < 0.0001). The baseline serum level of sCD26/DPP4 showed a significant negative correlation with the percent change of HMW adiponectin during the OGTT. In conclusion, the serum level of sCD26/DPP4 increased acutely after an oral glucose load in apparently healthy subjects. The abrupt increase of serum sCD26/DPP4 after a glucose load may be a marker of insulin resistance that could come from liver or muscle. Copyright © 2013 Mosby, Inc. All rights reserved.

Linagliptin: farmacology, efficacy and safety in type 2 diabetes treatment

PubMed Central

2013-01-01

Type 2 diabetes mellitus (T2DM) has a high prevalence and incidence around the world. The complex pathophysiology mechanism is among the barriers for diabetes treatment. Type 2 diabetes patients have dysfunction in incretin hormones (as glucagon-like peptide-1 or GLP-1, and glucose-dependent insulinotropic polypeptide or GIP). By inhibiting the dipeptidyl peptidase-4 (DPP-4) enzyme, it is possible to slow the inactivation of GLP-1 and GIP, promoting blood glucose level reduction in a glucose-dependent manner. Linagliptin is a highly specific and potent inhibitor of DPP-4 that is currently indicated for the treatment of type 2 diabetes. Clinical studies with linagliptin demonstrated efficacy in reducing glycated hemoglobin (HbA1c) levels in type 2 diabetes patients, while maintaining a placebo-like safety and tolerability profile. Linagliptin has an interesting pharmacokinetic profile in terms of its predominantly non-renal elimination and the main implication of this characteristic is that no dose adjustment is necessary in patients with renal disease. Also, no dose adjustment is required in patients with hepatic insufficiency, as well in elderly or obese patients. This article will review the pharmacokinetic profile, efficacy data and safety aspects of linagliptin in type 2 diabetes patients. PMID:23697612

More realistic power estimation for new user, active comparator studies: an empirical example.

PubMed

Gokhale, Mugdha; Buse, John B; Pate, Virginia; Marquis, M Alison; Stürmer, Til

2016-04-01

Pharmacoepidemiologic studies are often expected to be sufficiently powered to study rare outcomes, but there is sequential loss of power with implementation of study design options minimizing bias. We illustrate this using a study comparing pancreatic cancer incidence after initiating dipeptidyl-peptidase-4 inhibitors (DPP-4i) versus thiazolidinediones or sulfonylureas. We identified Medicare beneficiaries with at least one claim of DPP-4i or comparators during 2007-2009 and then applied the following steps: (i) exclude prevalent users, (ii) require a second prescription of same drug, (iii) exclude prevalent cancers, (iv) exclude patients age <66 years and (v) censor for treatment changes during follow-up. Power to detect hazard ratios (effect measure strongly driven by the number of events) ≥ 2.0 estimated after step 5 was compared with the naïve power estimated prior to step 1. There were 19,388 and 28,846 DPP-4i and thiazolidinedione initiators during 2007-2009. The number of drug initiators dropped most after requiring a second prescription, outcomes dropped most after excluding patients with prevalent cancer and person-time dropped most after requiring a second prescription and as-treated censoring. The naïve power (>99%) was considerably higher than the power obtained after the final step (~75%). In designing new-user active-comparator studies, one should be mindful how steps minimizing bias affect sample-size, number of outcomes and person-time. While actual numbers will depend on specific settings, application of generic losses in percentages will improve estimates of power compared with the naive approach mostly ignoring steps taken to increase validity. Copyright © 2015 John Wiley & Sons, Ltd.

A novel DPP6 isoform (DPP6-E) can account for differences between neuronal and reconstituted A-type K(+) channels.

PubMed

Maffie, Jonathon; Blenkinsop, Timothy; Rudy, Bernardo

2009-01-16

The channels mediating most of the somatodendritic A-type K(+) current in neurons are thought to be ternary complexes of Kv4 pore-forming subunits and two types of auxiliary subunits, the K(+) channel interacting proteins (KChIPs) and dipeptidyl-peptidase-like (DPPL) proteins. The channels expressed in heterologous expression systems by mixtures of Kv4.2, KChIP1 and DPP6-S resemble in many properties the A-type current in hippocampal CA1 pyramidal neurons and cerebellar granule cells, neurons with prominent A-type K(+) currents. However, the native currents have faster kinetics. Moreover, the A-type currents in neurons in intermediary layers of the superior colliculus have even faster inactivating rates. We have characterized a new DPP6 spliced isoform, DPP6-E, that produces in heterologous cells ternary Kv4 channels with very fast kinetics. DPP6-E is selectively expressed in a few neuronal populations in brain including cerebellar granule neurons, hippocampal pyramidal cells and neurons in intermediary layers of the superior colliculus. The effects of DPP6-E explain past discrepancies between reconstituted and native Kv4 channels in some neurons, and contributes to the diversity of A-type K(+) currents in neurons.

Molecular mechanisms redirecting the GLP-1 receptor signalling profile in pancreatic β-cells during type 2 diabetes.

PubMed

Roussel, Morgane; Mathieu, Julia; Dalle, Stéphane

2016-05-01

Treatments with β-cell preserving properties are essential for the management of type 2 diabetes (T2D), and the new therapeutic avenues, developed over the last years, rely on the physiological role of glucagon-like peptide-1 (GLP-1). Sustained pharmacological levels of GLP-1 are achieved by subcutaneous administration of GLP-1 analogues, while transient and lower physiological levels of GLP-1 are attained following treatment with inhibitors of dipeptidylpeptidase 4 (DPP4), an endoprotease which degrades the peptide. Both therapeutic classes display a sustained and durable hypoglycaemic action in patients with T2D. However, the GLP-1 incretin effect is known to be reduced in patients with T2D, and GLP-1 analogues and DPP4 inhibitors were shown to lose their effectiveness over time in some patients. The pathological mechanisms behind these observations can be either a decrease in GLP-1 secretion from intestinal L-cells and, as a consequence, a reduction in GLP-1 plasma concentrations, combined or not with a reduced action of GLP-1 in the β-cell, the so-called GLP-1 resistance. Much evidence for a GLP-1 resistance of the β-cell in subjects with T2D have emerged. Here, we review the potential roles of the genetic background, the hyperglycaemia, the hyperlipidaemia, the prostaglandin E receptor 3, the nuclear glucocorticoid receptor, the GLP-1R desensitization and internalisation processes, and the β-arrestin-1 expression levels on GLP-1 resistance in β-cells during T2D.

Dipeptidylpeptidase--IV, a key enzyme for the degradation of incretins and neuropeptides: activity and expression in the liver of lean and obese rats.

PubMed

Tarantola, E; Bertone, V; Milanesi, G; Capelli, E; Ferrigno, A; Neri, D; Vairetti, M; Barni, S; Freitas, I

2012-10-08

Given the scarcity of donors, moderately fatty livers (FLs) are currently being considered as possible grafts for orthotopic liver transplantation (OLT), notwithstanding their poor tolerance to conventional cold preservation. The behaviour of parenchymal and sinusoidal liver cells during transplantation is being studied worldwide. Much less attention has been paid to the biliary tree, although this is considered the Achille's heel even of normal liver transplantation. To evaluate the response of the biliary compartment of FLs to the various phases of OLT reliable markers are necessary. Previously we demonstrated that Alkaline Phosphatase was scarcely active in bile canaliculi of FLs and thus ruled it out as a marker. As an alternative, dipeptidylpeptidase-IV (DPP-IV), was investigated. This ecto-peptidase plays an important role in glucose metabolism, rapidly inactivating insulin secreting hormones (incretins) that are important regulators of glucose metabolism. DPP-IV inhibitors are indeed used to treat Type II diabetes. Neuropeptides regulating bile transport and composition are further important substrates of DPP-IV in the enterohepatic axis. DPP-IV activity was investigated with an azo-coupling method in the liver of fatty Zucker rats (fa/fa), using as controls lean Zucker (fa/+) and normal Wistar rats. Protein expression was studied by immunofluorescence with the monoclonal antibody (clone 5E8). In Wistar rat liver, DPP-IV activity and expression were high in the whole biliary tree, and moderate in sinusoid endothelial cells, in agreement with the literature. Main substrates of DPP-IV in hepatocytes and cholangiocytes could be incretins GLP-1 and GIP, and neuropeptides such as vasoactive intestinal peptide (VIP) and substance P, suggesting that these substances are inactivated or modified through the biliary route. In lean Zucker rat liver the enzyme reaction and protein expression patterns were similar to those of Wistar rat. In obese rat liver the patterns of DPP-IV activity and expression in hepatocytes reflected the morphological alterations induced by steatosis as lipid-rich hepatocytes had scarce activity, located either in deformed bile canaliculi or in the sinusoidal and lateral domains of the plasma membrane. These findings suggest that bile canaliculi in steatotic cells have an impaired capacity to inactivate incretins and neuropeptides. Incretin and/or neuropeptide deregulation is indeed thought to play important roles in obesity and insulin-resistance. No alteration in enzyme activity and expression was found in the upper segments of the biliary tree of obese respect to lean Zucker and Wistar rats. In conclusion, this research demonstrates that DPP-IV is a promising in situ marker of biliary functionality not only of normal but also of fatty rats. The approach, initially devised to investigate the behaviour of the liver during the various phases of transplantation, appears to have a much higher potentiality as it could be further exploited to investigate any pathological or stressful conditions involving the biliary tract (i.e., metabolic syndrome and cholestasis) and the response of the biliary tract to therapy and/or to surgery.

Dipeptidylpeptidase-IV, a key enzyme for the degradation of incretins and neuropeptides: activity and expression in the liver of lean and obese rats

PubMed Central

Tarantola, E.; Bertone, V.; Milanesi, G.; Capelli, E.; Ferrigno, A.; Neri, D.; Vairetti, M.; Barni, S.; Freitas, I.

2012-01-01

Given the scarcity of donors, moderately fatty livers (FLs) are currently being considered as possible grafts for orthotopic liver transplantation (OLT), notwithstanding their poor tolerance to conventional cold preservation. The behaviour of parenchymal and sinusoidal liver cells during transplantation is being studied worldwide. Much less attention has been paid to the biliary tree, although this is considered the Achille's heel even of normal liver transplantation. To evaluate the response of the biliary compartment of FLs to the various phases of OLT reliable markers are necessary. Previously we demonstrated that Alkaline Phosphatase was scarcely active in bile canaliculi of FLs and thus ruled it out as a marker. As an alternative, dipeptidylpeptidase-IV (DPP-IV), was investigated. This ecto-peptidase plays an important role in glucose metabolism, rapidly inactivating insulin secreting hormones (incretins) that are important regulators of glucose metabolism. DPP-IV inhibitors are indeed used to treat Type II diabetes. Neuropeptides regulating bile transport and composition are further important substrates of DPP-IV in the enterohepatic axis. DPP-IV activity was investigated with an azo-coupling method in the liver of fatty Zucker rats (fa/fa), using as controls lean Zucker (fa/+) and normal Wistar rats. Protein expression was studied by immunofluorescence with the monoclonal antibody (clone 5E8). In Wistar rat liver, DPP-IV activity and expression were high in the whole biliary tree, and moderate in sinusoid endothelial cells, in agreement with the literature. Main substrates of DPP-IV in hepatocytes and cholangiocytes could be incretins GLP-1 and GIP, and neuropeptides such as vasoactive intestinal peptide (VIP) and substance P, suggesting that these substances are inactivated or modified through the biliary route. In lean Zucker rat liver the enzyme reaction and protein expression patterns were similar to those of Wistar rat. In obese rat liver the patterns of DPP-IV activity and expression in hepatocytes reflected the morphological alterations induced by steatosis as lipid-rich hepatocytes had scarce activity, located either in deformed bile canaliculi or in the sinusoidal and lateral domains of the plasma membrane. These findings suggest that bile canaliculi in steatotic cells have an impaired capacity to inactivate incretins and neuropeptides. Incretin and/or neuropeptide deregulation is indeed thought to play important roles in obesity and insulin-resistance. No alteration in enzyme activity and expression was found in the upper segments of the biliary tree of obese respect to lean Zucker and Wistar rats. In conclusion, this research demonstrates that DPP-IV is a promising in situ marker of biliary functionality not only of normal but also of fatty rats. The approach, initially devised to investigate the behaviour of the liver during the various phases of transplantation, appears to have a much higher potentiality as it could be further exploited to investigate any pathological or stressful conditions involving the biliary tract (i.e., metabolic syndrome and cholestasis) and the response of the biliary tract to therapy and/or to surgery. PMID:23361237

NPY1–36 and PYY1–36 activate cardiac fibroblasts: an effect enhanced by genetic hypertension and inhibition of dipeptidyl peptidase 4

PubMed Central

Zhu, Xiao; Gillespie, Delbert G.

2015-01-01

Cardiac sympathetic nerves release neuropeptide Y (NPY)1–36, and peptide YY (PYY)1–36 is a circulating peptide; therefore, these PP-fold peptides could affect cardiac fibroblasts (CFs). We examined the effects of NPY1–36 and PYY1–36 on the proliferation of and collagen production ([3H]proline incorporation) by CFs isolated from Wistar-Kyoto (WKY) normotensive rats and spontaneously hypertensive rats (SHRs). Experiments were performed with and without sitagliptin, an inhibitor of dipeptidyl peptidase 4 [DPP4; an ectoenzyme that metabolizes NPY1–36 and PYY1–36 (Y1 receptor agonists) to NPY3–36 and PYY3–36 (inactive at Y1 receptors), respectively]. NPY1–36 and PYY1–36, but not NPY3–36 or PYY3–36, stimulated proliferation of CFs, and these effects were more potent than ANG II, enhanced by sitagliptin, blocked by BIBP3226 (Y1 receptor antagonist), and greater in SHR CFs. SHR CF membranes expressed more receptor for activated C kinase (RACK)1 [which scaffolds the Gi/phospholipase C (PLC)/PKC pathway] compared with WKY CF membranes. RACK1 knockdown (short hairpin RNA) and inhibition of Gi (pertussis toxin), PLC (U73122), and PKC (GF109203X) blocked the proliferative effects of NPY1–36. NPY1–36 and PYY1–36 stimulated collagen production more potently than did ANG II, and this was enhanced by sitagliptin and greater in SHR CFs. In conclusion, 1) NPY1–36 and PYY1–36, via the Y1 receptor/Gi/PLC/PKC pathway, activate CFs, and this pathway is enhanced in SHR CFs due to increased localization of RACK1 in membranes; and 2) DPP4 inhibition enhances the effects of NPY1–36 and PYY1–36 on CFs, likely by inhibiting the metabolism of NPY1–36 and PYY1–36. The implications are that endogenous NPY1–36 and PYY1–36 could adversely affect cardiac structure/function by activating CFs, and this may be exacerbated in genetic hypertension and by DPP4 inhibitors. PMID:26371160

Decapentaplegic and growth control in the developing Drosophila wing.

PubMed

Akiyama, Takuya; Gibson, Matthew C

2015-11-19

As a central model for morphogen action during animal development, the bone morphogenetic protein 2/4 (BMP2/4)-like ligand Decapentaplegic (Dpp) is proposed to form a long-range signalling gradient that directs both growth and pattern formation during Drosophila wing disc development. While the patterning role of Dpp secreted from a stripe of cells along the anterior-posterior compartmental boundary is well established, the mechanism by which a Dpp gradient directs uniform cell proliferation remains controversial and poorly understood. Here, to determine the precise spatiotemporal requirements for Dpp during wing disc development, we use CRISPR-Cas9-mediated genome editing to generate a flippase recognition target (FRT)-dependent conditional null allele. By genetically removing Dpp from its endogenous stripe domain, we confirm the requirement of Dpp for the activation of a downstream phospho-Mothers against dpp (p-Mad) gradient and the regulation of the patterning targets spalt (sal), optomotor blind (omb; also known as bifid) and brinker (brk). Surprisingly, however, third-instar wing blade primordia devoid of compartmental dpp expression maintain relatively normal rates of cell proliferation and exhibit only mild defects in growth. These results indicate that during the latter half of larval development, the Dpp morphogen gradient emanating from the anterior-posterior compartment boundary is not directly required for wing disc growth.

Gestational glucocorticoid exposure disrupts glucose homeostasis that is accompanied by increased endoglin and DPP-4 activity instead of GSK-3 in rats.

PubMed

Badmus, Olufunto O; Michael, Olugbenga S; Rabiu, Saheed; Olatunji, Lawrence A

2018-04-13

Gestational glucocorticoid (GC) treatment has been associated with cardiometabolic disorder (CMD) in offspring's in later life. Elevated dipeptidyl peptidase-4 (DPP-4) activity, endoglin and glycogen synthase kinase-3 (GSK-3) has also been implicated in the development of insulin resistance (IR) and/or vascular inflammation. We aimed to investigate the impact of GC exposure on glucose metabolism and the circulating levels of inflammatory biomarkers, DPP-4 activity and GSK-3 in pregnant rats. Pregnant Wistar rats received either vehicle or dexamethasone (DEX; 0.2 mg/kg; po) between gestational days 14 and 19. Gestational GC exposure resulted in impaired glucose homeostasis that is accompanied with elevated circulating levels of inflammatory biomarkers (endoglin, uric acid, and platelet/lymphocyte ratio), oxidative stress (malondialdehyde), blood viscosity, reduced NO level and increased DPP-4 activity. However, these effects were associated with atherogenic dyslipidemia and reduced GSK-3.We conclude that plasma endoglin, a marker of vascular inflammation, and plasma DPP-4 activity are increased in pregnant rats treated with GC during late gestation. Therefore, glucose deregulation associated with gestational GC exposure is through endoglin-/DPP-4-dependent but GSK-3-independent pathway. Copyright © 2018 Elsevier B.V. All rights reserved.

Shipboard Fluid System Diagnostics Using Non-Intrusive Load Monitoring

DTIC Science & Technology

2007-06-01

brute.s(3).data; tDPP = brute.s(3).time; FL = brute.s(4).data; tFL = brute.s(4).time; RM = brute.s(5).data; tRM = brute.s(5).time; DPF = brute.s...s’, max(tP1), files(n).name)); ylabel(’Power’); axis tight grid on; subplot(4,1,2); plot( tDPP , DPP, tDPF, DPF) ylabel(’DP Gauges’); axis

Dipeptidyl peptidase-4 activity might be a link between tumour necrosis factor alpha and insulin resistance in type 1 diabetes.

PubMed

Duvnjak, Lea; Blaslov, Kristina; Perković, Matea Nikolac; Ćuća, Jadranka Knežević

2016-08-01

Tumour necrosis factor alpha (TNF α) leads to β cell damage in type 1 diabetes (T1DM) but also causes insulin resistance (IR). It modulates dipeptidyl peptidase-4 (DPP-4) activity, adipokine linked with both IR and T1DM. We were interested if there is an association of TNF α in conjunction with DPP-4 and IR in T1DM. DPP-4 activity, TNF α concentration measurements, and insulin sensitivity calculation using estimated glucose disposal rate (eGDR) equation were performed in 70 T1DM patients. They were divided into two groups according to eGDR median. The group with higher IR had higher value of DPP-4 activity (27.57 ± 1.77 vs. 18.33 ± 1.14, p < 0.001) and TNF α concentration (12.91 ± 0.83 vs. 6.72 ± 0.36, p < 0.001). TNF α concentration and DPP-4 activity negatively correlated with eGDR (r = -0.616, p < 0.001 and r = -0.643, p < 0.001) while correlating positively with each other (r = 0.422; p = 0.001). The linear regression showed that eGDR decreases for 0.166 mg kg(-1) min(-1) by TNF α concentration increase of 1 pg/mL (p < 0.001) and for 0.090 mg kg(-1) min(-1) by DPP-4 activity increase of 1 U/L (p = 0.001) when adjusted for age, gender disease duration, glycated haemoglobin, body mass index and waist-to-hip ratio. eGDR decreased by additional 0.60 mg kg(-1) min(-1) (B = -0.150, p < 0.001) when DPP-4 activity was additionally adjusted for TNF α. TNF α concentration is associated with IR, correlates with its severity and increases the drop in insulin sensitivity modulated by DPP-4 activity. Whether TNF α involvement in the insulin signalling pathway is mediated by DPP-4 activity needs to be further evaluated.

The incretin effect in healthy individuals and those with type 2 diabetes: physiology, pathophysiology, and response to therapeutic interventions.

PubMed

Nauck, Michael A; Meier, Juris J

2016-06-01

The incretin effect describes the phenomenon whereby oral glucose elicits higher insulin secretory responses than does intravenous glucose, despite inducing similar levels of glycaemia, in healthy individuals. This effect, which is uniformly defective in patients with type 2 diabetes, is mediated by the gut-derived incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). The importance of the incretin effect for the maintenance of glucose homoeostasis is clearly established, and incretin-based therapies are among the most promising new therapies for type 2 diabetes. However, despite the effectiveness of these therapies in many patients, the idea that they restore the incretin effect is a common misconception. In type 2 diabetes, the endocrine pancreas remains responsive to GLP-1 but is no longer responsive to GIP, which is the most likely reason for a reduced or absent incretin effect. Incretin-based drugs, including GLP-1 receptor agonists and dipeptidyl peptidase 4 (DPP-4) inhibitors, stimulate GLP-1 receptors and thus augment insulin secretion in response to both oral and intravenous glucose stimulation, thereby abolishing any potential difference in the responses to these stimuli. These drugs therefore do not restore the defective incretin effect in patients. By contrast, some bariatric surgical procedures enhance GLP-1 responses and also restore the incretin effect in obese individuals with type 2 diabetes. Thus, not all biological actions elicited by the stimulation of GLP-1 receptors lead to quantitative changes to the incretin effect. Copyright © 2016 Elsevier Ltd. All rights reserved.

Boundary Dpp promotes growth of medial and lateral regions of the Drosophila wing.

PubMed

Barrio, Lara; Milán, Marco

2017-07-04

The gradient of Decapentaplegic (Dpp) in the Drosophila wing has served as a paradigm to characterize the role of morphogens in regulating patterning. However, the role of this gradient in regulating tissue size is a topic of intense debate as proliferative growth is homogenous. Here, we combined the Gal4/UAS system and a temperature-sensitive Gal80 molecule to induce RNAi-mediated depletion of dpp and characterise the spatial and temporal requirement of Dpp in promoting growth. We show that Dpp emanating from the AP compartment boundary is required throughout development to promote growth by regulating cell proliferation and tissue size. Dpp regulates growth and proliferation rates equally in central and lateral regions of the developing wing appendage and reduced levels of Dpp affects similarly the width and length of the resulting wing. We also present evidence supporting the proposal that graded activity of Dpp is not an absolute requirement for wing growth.

High Gravity (g) Combustion

DTIC Science & Technology

2006-02-01

UNICORN (Unsteady Ignition and Combustion with Reactions) code10. Flame propagation in a tube that is 50-mm wide and 1000-mm long (similar to that...turbine engine manufacturers, estimating the primary zone space heating rate. Both combustion systems, from Company A and Company B, required a much...MBTU/atm-hr-ft3) Te m pe ra tu re R is e (K ) dP/P = 2% dP/P = 2.5% dP/P = 3% dP/P = 3.5% dP/P = 4% Company A Company B Figure 13: Heat Release Rate

Efficacy of sitagliptin on blood glucose fluctuation in Japanese type 2 diabetic patients with basal-supported oral therapy.

PubMed

Takahara, Mitsuyoshi; Shiraiwa, Toshihiko; Kaneto, Hideaki; Katakami, Naoto; Matsuoka, Taka-Aki; Shimomura, Iichiro

2012-01-01

We retrospectively investigated the effect of adding dipeptidyl peptidase-4 (DPP-4) inhibitor and tapering sulfonylurea on blood glucose fluctuation in Asian patients with type 2 diabetes mellitus under basal-supported oral therapy (BOT). We recruited twenty-two consecutive Japanese patients with type 2 diabetes mellitus who had blood glucose fluctuation under the combination therapy of insulin glargine and glimepiride and had sitagliptin initiated with glimepiride tapared. Their hemoglobin A1c levels and mean blood glucose profiles of seven points in self-monitoring blood glucose (SMBG) were 7.4 ± 0.6% and 8.6 ± 2.0 mmol/L, respectively. Sitagliptin was initiated with the dose of 50 mg per day and titrated up to 100 mg per day when necessary. Glimepiride was withdrawn if possible. Blood glucose fluctuation was evaluated with SMBG by calculating M-value, its range (the difference of maximum and minimum blood glucose levels), and its coefficient of variation (CV). Two months after sitagliptin add-on, M-value was decreased from 19 ± 13 to 13 ± 8 (p = 0.04). Blood glucose range and CV were also improved from 9.6 ± 2.9 mmol/L to 7.9 ± 2.6 mmol/L (p = 0.01), and from 33 ± 8% to 29 ± 8% (p < 0.01), respectively. Hemoglobin A1c levels and mean blood glucose profiles were unchanged (p = 0.93 and 0.47). In conclusion, blood glucose fluctuation was significantly improved two months after adding sitagliptin and tapering glimepiride in type 2 diabetic Japanese patients who were treated by BOT with insulin glargine and glimepiride.

Lower dipeptidyl peptidase-4 following exercise training plus weight loss is related to increased insulin sensitivity in adults with metabolic syndrome.

PubMed

Malin, Steven K; Huang, Hazel; Mulya, Anny; Kashyap, Sangeeta R; Kirwan, John P

2013-09-01

Dipeptidyl peptidase-4 (DPP-4) is a circulating glycoprotein that impairs insulin-stimulated glucose uptake and is linked to obesity and metabolic syndrome. However, the effect of exercise on plasma DPP-4 in adults with metabolic syndrome is unknown. Therefore, we determined the effect of exercise on DPP-4 and its role in explaining exercise-induced improvements in insulin sensitivity. Fourteen obese adults (67.9±1.2 years, BMI: 34.2±1.1kg/m(2)) with metabolic syndrome (ATP III criteria) underwent a 12-week supervised exercise intervention (60min/day for 5 days/week at ∼85% HRmax). Plasma DPP-4 was analyzed using an enzyme-linked immunosorbent assay. Insulin sensitivity was measured using the euglycemic-hyperinsulinemic clamp (40mU/m(2)/min) and estimated by HOMA-IR. Visceral fat (computerized tomography), 2-h glucose levels (75g oral glucose tolerance), and basal fat oxidation as well as aerobic fitness (indirect calorimetry) were also determined before and after exercise. The intervention reduced visceral fat, lowered blood pressure, glucose and lipids, and increased aerobic fitness (P<0.05). Exercise improved clamp-derived insulin sensitivity by 75% (P<0.001) and decreased HOMA-IR by 15% (P<0.05). Training decreased plasma DPP-4 by 10% (421.8±30.1 vs. 378.3±32.5ng/ml; P<0.04), and the decrease in DPP-4 was associated with clamp-derived insulin sensitivity (r=-0.59; P<0.04), HOMA-IR (r=0.59; P<0.04) and fat oxidation (r=-0.54; P<0.05). Increased fat oxidation also correlated with lower 2-h glucose levels (r=-0.64; P<0.02). Exercise training reduces plasma DPP-4, which may be linked to elevated insulin sensitivity and fat oxidation. Maintaining low plasma DPP-4 concentrations is a potential mechanism whereby exercise plus weight loss prevents/delays the onset of type 2 diabetes in adults with metabolic syndrome. Copyright © 2013 Elsevier Inc. All rights reserved.

Regulation of Dpp activity by tissue-specific cleavage of an upstream site within the prodomain

PubMed Central

Sopory, Shailaja; Kwon, Sunjong; Wehrli, Marcel; Christian, Jan L.

2010-01-01

BMP4 is synthesized as an inactive precursor that is cleaved at two sites during maturation: initially at a site (S1) adjacent to the ligand domain, and then at an upstream site (S2) within the prodomain. Cleavage at the second site regulates the stability of mature BMP4 and this in turn influences its signaling intensity and range of action. The Drosophila ortholog of BMP4, Dpp, functions as a long- or short-range signaling molecule in the wing disc or embryonic midgut, respectively but mechanisms that differentially regulate its bioactivity in these tissues have not been explored. In the current studies we demonstrate, by dpp mutant rescue, that cleavage at the S2 site of proDpp is required for development of the wing and leg imaginal discs, whereas cleavage at the S1 site is sufficient to rescue Dpp function in the midgut. Both the S1 and S2 site of proDpp are cleaved in the wing disc, and S2-cleavage is essential to generate sufficient ligand to exceed the threshold for pMAD activation at both short- and long-range in most cells. By contrast, proDpp is cleaved at the S1 site alone in the embryonic mesoderm and this generates sufficient ligand to activate physiological target genes in neighboring cells. These studies provide the first biochemical and genetic evidence that that selective cleavage of the S2 site of proDPP provides a tissue-specific mechanism for regulating Dpp activity, and that differential cleavage can contribute to, but is not an absolute determinant of signaling range. PMID:20659445

Therapeutic Potential of Date Palm Pollen for Testicular Dysfunction Induced by Thyroid Disorders in Male Rats.

PubMed

El-Kashlan, Akram M; Nooh, Mohammed M; Hassan, Wafaa A; Rizk, Sherine M

2015-01-01

Hyper- or hypothyroidism can impair testicular function leading to infertility. The present study was designed to examine the protective effect of date palm pollen (DPP) extract on thyroid disorder-induced testicular dysfunction. Rats were divided into six groups. Group I was normal control. Group II received oral DPP extract (150 mg kg(-1)), group III (hyperthyroid group) received intraperitoneal injection of L-thyroxine (L-T4, 300 μg kg(-1); i.p.), group IV received L-T4 plus DPP extract, group V (hypothyroid group) received propylthiouracil (PTU, 10 mg kg(-1); i.p.) and group VI received PTU plus DPP extract. All treatments were given every day for 56 days. L-T4 or PTU lowered genital sex organs weight, sperm count and motility, serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone (T), testicular function markers and activities of testicular 3β-hydroxysteroid dehydrogenase (3β-HSD) and 17β-hydroxysteroid dehydrogenase (17β-HSD). Moreover, L-T4 or PTU increased estradiol (E2) serum level, testicular oxidative stress, DNA damage and apoptotic markers. Morphometric and histopathologic studies backed these observations. Treatment with DPP extract prevented LT4- or PTU induced changes. In addition, supplementation of DPP extract to normal rats augmented sperm count and motility, serum levels of LH, T and E2 paralleled with increased activities of 3β-HSD and 17β-HSD as well as testicular antioxidant status. These results provide evidence that DPP extract may have potential protective effects on testicular dysfunction induced by altered thyroid hormones.

Therapeutic Potential of Date Palm Pollen for Testicular Dysfunction Induced by Thyroid Disorders in Male Rats

PubMed Central

El-Kashlan, Akram M.; Nooh, Mohammed M.; Hassan, Wafaa A.; Rizk, Sherine M.

2015-01-01

Hyper- or hypothyroidism can impair testicular function leading to infertility. The present study was designed to examine the protective effect of date palm pollen (DPP) extract on thyroid disorder-induced testicular dysfunction. Rats were divided into six groups. Group I was normal control. Group II received oral DPP extract (150 mg kg-1), group III (hyperthyroid group) received intraperitoneal injection of L-thyroxine (L-T4, 300μg kg-1; i.p.), group IV received L-T4 plus DPP extract, group V (hypothyroid group) received propylthiouracil (PTU, 10 mg kg-1; i.p.) and group VI received PTU plus DPP extract. All treatments were given every day for 56 days. L-T4 or PTU lowered genital sex organs weight, sperm count and motility, serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone (T), testicular function markers and activities of testicular 3β-hydroxysteroid dehydrogenase (3β-HSD) and 17β-hydroxysteroid dehydrogenase (17β-HSD). Moreover, L-T4 or PTU increased estradiol (E2) serum level, testicular oxidative stress, DNA damage and apoptotic markers. Morphometric and histopathologic studies backed these observations. Treatment with DPP extract prevented LT4- or PTU induced changes. In addition, supplementation of DPP extract to normal rats augmented sperm count and motility, serum levels of LH, T and E2 paralleled with increased activities of 3β-HSD and 17β-HSD as well as testicular antioxidant status. These results provide evidence that DPP extract may have potential protective effects on testicular dysfunction induced by altered thyroid hormones. PMID:26425844

Simultaneous determination of zinc and chromate in cooling water by differential pulse polarography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jindal, V.K.; Kham, M.A.; Bhatnagar, R.M.

1985-01-01

The use of differential pulse polarography (DPP) for the simultaneous determination of zinc and chromate in cooling water is reported where zinc (5 ppm), chromate (20 ppm), and polyphosphate (50 ppm) formulation is used as a corrosion inhibitor. This will help in effective control of cooling tower performance. The DPP method has been applied for the simultaneous determination of zinc and chromate ions in process and cooling water samples from fertilizer plants in India. The method is based on the reduction of Cr and Zn on SMDE in 1 M NH3-0.1 M NH/sub 4/Cl and 0.005% gelatine supporting electrolyte. Duemore » to interference it is essential to complex calcium ions by adding polyphosphate and to destroy NO/sub 2//sup -//NO/sub 3//sup -/ by adding sulfamic acid along with hydrochloric acid before the actual recording of DP polarograms. The present DP polarographic method for the simultaneous determination of zinc and chromate is comparable in its utility and applicability with spectrophotometric methods. The method has a better accuracy and higher sensitivity and is quick, as both of the ions can be determined in a single scan. 10 references, 4 figures, 5 tables.« less

Vildagliptin and its metabolite M20.7 induce the expression of S100A8 and S100A9 in human hepatoma HepG2 and leukemia HL-60 cells

PubMed Central

Asakura, Mitsutoshi; Karaki, Fumika; Fujii, Hideaki; Atsuda, Koichiro; Itoh, Tomoo; Fujiwara, Ryoichi

2016-01-01

Vildagliptin is a potent, orally active inhibitor of dipeptidyl peptidase-4 (DPP-4) for the treatment of type 2 diabetes mellitus. It has been reported that vildagliptin can cause hepatic dysfunction in patients. However, the molecular-mechanism of vildagliptin-induced liver dysfunction has not been elucidated. In this study, we employed an expression microarray to determine hepatic genes that were highly regulated by vildagliptin in mice. We found that pro-inflammatory S100 calcium-binding protein (S100) a8 and S100a9 were induced more than 5-fold by vildagliptin in the mouse liver. We further examined the effects of vildagliptin and its major metabolite M20.7 on the mRNA expression levels of S100A8 and S100A9 in human hepatoma HepG2 and leukemia HL-60 cells. In HepG2 cells, vildagliptin, M20.7, and sitagliptin – another DPP-4 inhibitor – induced S100A9 mRNA. In HL-60 cells, in contrast, S100A8 and S100A9 mRNAs were significantly induced by vildagliptin and M20.7, but not by sitagliptin. The release of S100A8/A9 complex in the cell culturing medium was observed in the HL-60 cells treated with vildagliptin and M20.7. Therefore, the parental vildagliptin- and M20.7-induced release of S100A8/A9 complex from immune cells, such as neutrophils, might be a contributing factor of vildagliptin-associated liver dysfunction in humans. PMID:27759084

Vildagliptin and its metabolite M20.7 induce the expression of S100A8 and S100A9 in human hepatoma HepG2 and leukemia HL-60 cells.

PubMed

Asakura, Mitsutoshi; Karaki, Fumika; Fujii, Hideaki; Atsuda, Koichiro; Itoh, Tomoo; Fujiwara, Ryoichi

2016-10-19

Vildagliptin is a potent, orally active inhibitor of dipeptidyl peptidase-4 (DPP-4) for the treatment of type 2 diabetes mellitus. It has been reported that vildagliptin can cause hepatic dysfunction in patients. However, the molecular-mechanism of vildagliptin-induced liver dysfunction has not been elucidated. In this study, we employed an expression microarray to determine hepatic genes that were highly regulated by vildagliptin in mice. We found that pro-inflammatory S100 calcium-binding protein (S100) a8 and S100a9 were induced more than 5-fold by vildagliptin in the mouse liver. We further examined the effects of vildagliptin and its major metabolite M20.7 on the mRNA expression levels of S100A8 and S100A9 in human hepatoma HepG2 and leukemia HL-60 cells. In HepG2 cells, vildagliptin, M20.7, and sitagliptin - another DPP-4 inhibitor - induced S100A9 mRNA. In HL-60 cells, in contrast, S100A8 and S100A9 mRNAs were significantly induced by vildagliptin and M20.7, but not by sitagliptin. The release of S100A8/A9 complex in the cell culturing medium was observed in the HL-60 cells treated with vildagliptin and M20.7. Therefore, the parental vildagliptin- and M20.7-induced release of S100A8/A9 complex from immune cells, such as neutrophils, might be a contributing factor of vildagliptin-associated liver dysfunction in humans.

Linagliptin prevents atrial electrical and structural remodeling in a canine model of atrial fibrillation.

PubMed

Igarashi, Tazuru; Niwano, Shinichi; Niwano, Hiroe; Yoshizawa, Tomoharu; Nakamura, Hironori; Fukaya, Hidehira; Fujiishi, Tamami; Ishizue, Naruya; Satoh, Akira; Kishihara, Jun; Murakami, Masami; Ako, Junya

2018-05-02

Dipeptidyl peptidase 4 (DPP-4) inhibitors have recently been reported to exhibit additional cardioprotective effects; however, their effect in atrial remodeling, such as in atrial fibrillation (AF), remains unclear. In this study, the effect of linagliptin on atrial electrical and structural remodeling was evaluated in a canine AF model. Sixteen beagle dogs with 3-week atrial rapid stimulation were divided into the linagliptin group (9 mg/kg/day, n = 8) and pacing control group (n = 8). Three additional dogs without rapid pacing were assigned into non-pacing group, which was used as sham in this study. In the dogs with rapid pacing, the atrial effective refractory period (AERP), conduction velocity (CV), and AF inducibility were evaluated and blood was sampled every week. After the entire protocol, atrial tissue was sampled for histological examinations using HE, Azan, and dihydroethidium (DHE) staining to evaluate any tissue damage or oxidative stress. The pacing control group exhibited a gradual AERP shortening and CV decrease along the time course as previously reported. In the linagliptin group, the AERP shortening was not affected, but the CV decrease was suppressed in comparison to the control group (p < 0.05). The AF inducibility was increased in the control group and suppressed in the linagliptin group (p < 0.05). The control group exhibited tissue fibrosis, the degree of which was suppressed in the linagliptin group. DHE staining exhibited suppression of the reactive oxygen species expression in the linagliptin group in comparison to the pacing control group. Linagliptin, a DPP-4-inhibitor, suppressed the AF inducibility, CV decrease, and overexpression of oxidative stress in the canine AF model. Such suppressive effects of linagliptin on AF in the canine model may possibly be related to the anti-oxidative effect.

Boundary Dpp promotes growth of medial and lateral regions of the Drosophila wing

PubMed Central

Barrio, Lara; Milán, Marco

2017-01-01

The gradient of Decapentaplegic (Dpp) in the Drosophila wing has served as a paradigm to characterize the role of morphogens in regulating patterning. However, the role of this gradient in regulating tissue size is a topic of intense debate as proliferative growth is homogenous. Here, we combined the Gal4/UAS system and a temperature-sensitive Gal80 molecule to induce RNAi-mediated depletion of dpp and characterise the spatial and temporal requirement of Dpp in promoting growth. We show that Dpp emanating from the AP compartment boundary is required throughout development to promote growth by regulating cell proliferation and tissue size. Dpp regulates growth and proliferation rates equally in central and lateral regions of the developing wing appendage and reduced levels of Dpp affects similarly the width and length of the resulting wing. We also present evidence supporting the proposal that graded activity of Dpp is not an absolute requirement for wing growth. DOI: http://dx.doi.org/10.7554/eLife.22013.001 PMID:28675372

DPP8/9 inhibition induces pro-caspase-1-dependent monocyte and macrophage pyroptosis

PubMed Central

Okondo, Marian C.; Johnson, Darren C.; Sridharan, Ramya; Go, Eun Bin; Chui, Ashley J.; Wang, Mitchell S.; Poplawski, Sarah E.; Wu, Wengen; Liu, Yuxin; Lai, Jack H.; Sanford, David G.; Arciprete, Michael O.; Golub, Todd R.; Bachovchin, William W.; Bachovchin, Daniel A.

2017-01-01

Val-boroPro (talabostat, PT-100), a nonselective inhibitor of post-proline cleaving serine proteases, stimulates mammalian immune systems through an unknown mechanism of action. Despite this lack of mechanistic understanding, Val-boroPro has attracted significant interest as a potential anticancer agent, reaching Phase III trials in humans. Here we show that Val-boroPro stimulates the immune system by triggering a proinflammatory form of cell death in monocytes and macrophages known as pyroptosis. We demonstrate that the inhibition of two serine proteases, DPP8 and DPP9, activates the proprotein form of caspase-1 independent of the inflammasome adaptor ASC. Activated pro-caspase-1 does not efficiently process itself or IL-1β, but does cleave and activate gasdermin D to induce pyroptosis. Mice lacking caspase-1 do not show immune stimulation after treatment with Val-boroPro. Our data identifies the first small molecule that induces pyroptosis and reveals a new checkpoint that controls the activation of the innate immune system. PMID:27820798

Influence of PNA containing 8-aza-7-deazaadenine on structure stability and binding affinity of PNA·DNA duplex: insights from thermodynamics, counter ion, hydration and molecular dynamics analysis.

PubMed

Gupta, Sharad K; Sur, Souvik; Prasad Ojha, Rajendra; Tandon, Vibha

2013-07-01

This paper describes the synthesis of a novel 8-aza-7-deazapurin-2,6-diamine (DPP)-containing peptide nucleic acid (PNA) monomer and Boc protecting group-based oligomerization of PNA, replacing adenine (A) with DPP monomers in the PNA strand. The PNA oligomers were synthesized against the biologically relevant SV40 promoter region (2494-AATTTTTTTTATTTA-2508) of pEGFP-N3 plasmid. The DPP-PNA·DNA duplex showed enhanced stability as compared to normal duplex (A-PNA·DNA). The electronic distribution of DPP monomer suggested that DPP had better electron donor properties over 2,6-diamino purine. UV melting and thermodynamic analysis revealed that the PNA oligomer containing a diaminopyrazolo(3,4-d)pyrimidine moiety (DPP) stabilized the PNA·DNA hybrids compared to A-PNA·DNA. DPP-PNA·DNA duplex showed higher water activity (Δnw = 38.5) in comparison to A-PNA·DNA duplex (Δnw = 14.5). The 50 ns molecular dynamics simulations of PNA·DNA duplex containing DPP or unmodified nucleobase-A showed average H-bond distances in the DPP-dT base pair of 2.90 Å (OH-N bond) and 2.91 Å (NH-N bond), which were comparably shorter than in the A-dT base pair, in which the average distances were 3.18 Å (OH-N bond) and 2.97 Å (NH-N bond), and there was one additional H-bond in the DPP-dT base pair of around 2.98 Å (O2H-N2 bond), supporting the higher stability of DPP-PNA·DNA. The analysis of molecular dynamics simulation data showed that the system binding free energy increased at a rate of approximately -4.5 kcal mol(-1) per DPP base of the PNA·DNA duplex. In summary, increased thermal stability, stronger hydrogen bonding and more stable conformation in the DPP-PNA·DNA duplex make it a better candidate as antisense/antigene therapeutic agents.

A systematic literature review on the efficacy–effectiveness gap: comparison of randomized controlled trials and observational studies of glucose-lowering drugs

PubMed Central

Ankarfeldt, Mikkel Z; Adalsteinsson, Erpur; Groenwold, Rolf HH; Ali, M Sanni; Klungel, Olaf H

2017-01-01

Aim To identify a potential efficacy–effectiveness gap and possible explanations (drivers of effectiveness) for differences between results of randomized controlled trials (RCTs) and observational studies investigating glucose-lowering drugs. Methods A systematic literature review was conducted in English language articles published between 1 January, 2000 and 31 January, 2015 describing either RCTs or observational studies comparing glucagon-like peptide-1 analogs (GLP-1) with insulin or comparing dipeptidyl peptidase-4 inhibitors (DPP-4i) with sulfonylurea, all with change in glycated hemoglobin (HbA1c) as outcome. Medline, Embase, Current Content, and Biosis were searched. Information on effect estimates, baseline characteristics of the study population, publication year, study duration, and number of patients, and for observational studies, characteristics related to confounding adjustment and selection- and information bias were extracted. Results From 312 hits, 11 RCTs and 7 observational studies comparing GLP-1 with insulin, and from 474 hits, 16 RCTs and 4 observational studies comparing DPP-4i with sulfonylurea were finally included. No differences were observed in baseline characteristics of the study populations (age, sex, body mass index, time since diagnosis of type 2 diabetes mellitus, and HbA1c) or effect sizes across study designs. Mean effect sizes ranged from −0.43 to 0.91 and from −0.80 to 1.13 in RCTs and observational studies, respectively, comparing GLP-1 with insulin, and from −0.13 to 2.70 and −0.20 to 0.30 in RCTs and observational studies, respectively, comparing DPP-4i and sulfonylurea. Generally, the identified observational studies held potential flaws with regard to confounding adjustment and selection- and information bias. Conclusions Neither potential drivers of effectiveness nor an efficacy–effectiveness gap were identified. However, the limited number of studies and potential problems with confounding adjustment, selection- and information bias in the observational studies, may have hidden a true efficacy-effectiveness gap. PMID:28176959

Delivery of two-step transcription amplification exendin-4 plasmid system with arginine-grafted bioreducible polymer in type 2 diabetes animal model

PubMed Central

Kim, Pyung-Hwan; Lee, Minhyung; Kim, Sung Wan

2012-01-01

Exendin-4, glucagon-like peptide 1 (GLP-1) receptor agonist, is an exocrine hormone, which has potent insulinotropic actions similar to GLP-1 such as stimulating insulin biosynthesis, facilitating glucose-concentration dependent insulin secretion, slowing gastric emptying, reducing food intake and stimulating β-cell proliferation. Exendin-4, also, has a longer half-life than GLP-1, due to itsresistance to degradation by dipeptidyl peptidase IV (DPP-IV). In spite of its many advantages as a therapeutic agent for diabetes, its clinical application is still restricted. Thus, to improve the activity of exendin-4 in vivo, gene therapy system was developed as an alternative method. An exendin-4 expression system was constructed using the two-step transcription amplification (TSTA) system, which is composed of pβ-Gal4-p65 and pUAS-SP-exendin-4 with combining the advantages of signal peptide (SP) in order to facilitate its secretion in ectopic cells or tissue. Arginine-grafted cyctaminebisacrylamide-diaminohexane polymer (ABP) was used as a gene carrier. Increased expression of exendin-4, glucose dependent insulin secretion in NIT-1 insulinoma cells, and high insulin expression in the presence of DPP-IV were evaluated in vitro after delivery of ABP/TSTA-SP-exendin-4. Blood glucose levels in diabetic mice were decreased dramatically from the third day for experimental period after single intravenous administration with ABP/TSTA-SP-exendin-4. The highest insulinotropic effect of exendin-4 was also observed in the ABP/TSTA/SP-exendin-4-treated mice groups, compared with the others groups from the 3rd day after injection. TSTA exendin-4 expression system with SP and ABP polymer has a potential gene therapy for the treatment of type 2 diabetes. PMID:22705459

An easy one-pot synthesis of diverse 2,5-di(2-pyridyl)pyrroles: a versatile entry point to metal complexes of functionalised, meridial and tridentate 2,5-di(2-pyridyl)pyrrolato ligands.

PubMed

McSkimming, Alex; Diachenko, Vera; London, Rachel; Olrich, Kiara; Onie, C Jessica; Bhadbhade, Mohan M; Bucknall, Martin P; Read, Roger W; Colbran, Stephen B

2014-09-01

A wide variety of 2,5-di(2-pyridyl)pyrroles (dppHs) substituted at the C3 and C4 positions of the pyrrole core were obtained by direct condensation of a 2-pyridylcarboxaldehyde (2 equiv), an α-methylene ketone with at least one electron-withdrawing substituent and ammonium acetate. A novel 2,5-di(1,10-phenanthrolin-2-yl)pyrrole was also characterised. The dppHs provide a direct, quick entry to dipyridylpyrrolato (dpp(-) )-metal complexes. The meridial tridentate dpp(-) ligand is a useful anionic analogue of the terpyridyl ligand. The first (dpp)Ru complexes are described; the 3,4-substitution of the central pyrrole significantly perturbs the potentials of the redox processes of these complexes. A [(dpp)Ru(bpy)(MeCN)](+) (bpy=2,2'-bipyridine) complex is an electrocatalyst for the reductive disproportionation of carbon dioxide to carbon monoxide and the carbonate ion. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diketopyrrolopyrrole-based π-bridged donor-acceptor polymer for photovoltaic applications.

PubMed

Li, Wenting; Lee, Taegweon; Oh, Soong Ju; Kagan, Cherie R

2011-10-01

We report the synthesis, properties, and photovoltaic applications of a new conjugated copolymer (C12DPP-π-BT) containing a donor group (bithiophene) and an acceptor group (2,5-didodecylpyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione), bridged by a phenyl group. Using cyclic voltammetry, we found the energy levels of C12DPP-π-BT are intermediate to common electron donor and acceptor photovoltaic materials, poly (3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), respectively. Whereas P3HT and PCBM are exclusively electron donating or accepting, we predict C12DPP-π-BT may uniquely serve as either an electron donor or an acceptor when paired with PCBM or P3HT forming junctions with large built-in potentials. We confirmed the ambipolar nature of C12DPP-π-BT in space charge limited current measurements and in C12DPP-π-BT:PCBM and C12DPP-π-BT:P3HT bulk heterojunction solar cells, achieving power conversion efficiencies of 1.67% and 0.84%, respectively, under illumination of AM 1.5G (100 mW/cm(2)). Adding diiodooctane to C12DPP-π-BT:PCBM improved donor-acceptor inter-mixing and film uniformity, and therefore enhanced charge separation and overall device efficiency. Using higher-molecular-weight polymer C12DPP-π-BT in both C12DPP-π-BT:PCBM and C12DPP-π-BT:P3HT devices improved charge transport and hence the performance of the solar cells. In addition, we compared the structural and electronic properties of C12DPP-π-BT:PCBM and C12DPP-π-BT:P3HT blends, representing the materials classes of polymer:fullerene and polymer:polymer blends. In C12DPP-π-BT:PCBM blends, higher short circuit currents were obtained, consistent with faster charge transfer and balanced electron and hole transport, but lower open circuit voltages may be reduced by trap-assisted recombination and interfacial recombination losses. In contrast, C12DPP-π-BT:P3HT blends exhibit higher open circuit voltage, but short circuit currents were limited by charge transfer between the polymers. In conclusion, C12DPP-π-BT is a promising material with intrinsic ambipolar characteristics for organic photovoltaics and may operate as either a donor or acceptor in the design of bulk heterojunction solar cells. © 2011 American Chemical Society

Dipeptidyl peptidase 4 – an important digestive peptidase in Tenebrio molitor larvae

USDA-ARS?s Scientific Manuscript database

Dipeptidyl peptidase 4 (DPP 4) is a proline specific serine peptidase that plays an important role in different regulatory processes in mammals. In this report, we isolated and characterized a unique secreted digestive DPP 4 from the anterior midgut of a stored product pest, Tenebrio molitor larvae ...

Evaluation of novel TGR5 agonist in combination with Sitagliptin for possible treatment of type 2 diabetes.

PubMed

Agarwal, Sameer; Sasane, Santosh; Kumar, Jeevan; Deshmukh, Prashant; Bhayani, Hitesh; Giri, Poonam; Giri, Suresh; Soman, Shubhangi; Kulkarni, Neelima; Jain, Mukul

2018-06-01

TGR5 is a member of G protein-coupled receptor (GPCR) superfamily, a promising molecular target for metabolic diseases. Activation of TGR5 promotes secretion of glucagon-like peptide-1 (GLP-1), which activates insulin secretion. A series of 2-thio-imidazole derivatives have been identified as novel, potent and orally efficacious TGR5 agonists. Compound 4d, a novel TGR5 agonist, in combination with Sitagliptin, a DPP-4 inhibitor, has demonstrated an adequate GLP-1 secretion and glucose lowering effect in animal models, suggesting a potential clinical option in treatment of type-2 diabetes. Copyright © 2018 Elsevier Ltd. All rights reserved.

The role of incretin-based therapies in prediabetes: a review.

PubMed

Ahmadieh, Hala; Azar, Sami T

2014-12-01

Prediabetes, a high-risk state for future development of diabetes, is prevalent globally. Abnormalities in the incretin axis are important in the progression of B-cell failure in type 2 diabetes. Incretin based therapy was found to improve B cell mass and glycaemic control in addition to having multiple beneficial effects on the systolic and diastolic blood pressure, weight loss in addition to their other beneficial effects on the liver and cardiovascular system. In prediabetes, several well-designed preventive trials have shown that lifestyle and pharmacologic interventions such as metformin, thiazolidinediones (TZD), acarbose and, nateglinide and orlistat, are effective in reducing diabetes development. In recent small studies, incretin based therapy (DPP IV inhibitors and GLP-1 agonists) have also been extended to patients with prediabetes since it was shown to better preserve B-cell function and mass in animal studies and in clinical trials and it was also shown to help maintain good long term metabolic control. Because of the limited studies and clinical experience, their side effects and costs currently guidelines do not recommend incretin-based therapies as an option for treatment in patients with prediabetes. With future clinical trials and studies they may be recommended for patients with impaired fasting glucose or impaired glucose tolerance. Copyright © 2014 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.

Comparative Studies on Thermal, Mechanical, and Flame Retardant Properties of PBT Nanocomposites via Different Oxidation State Phosphorus-Containing Agents Modified Amino-CNTs.

PubMed

Zhu, San-E; Wang, Li-Li; Chen, Hao; Yang, Wei; Yuen, Anthony Chun-Yin; Chen, Timothy Bo-Yuan; Luo, Cheng; Bi, Wen-Mei; Hu, En-Zhu; Zhang, Jian; Si, Jing-Yu; Lu, Hong-Dian; Hu, Kun-Hong; Chan, Qing Nian; Yeoh, Guan Heng

2018-01-26

High-performance poly(1,4-butylene terephthalate) (PBT) nanocomposites have been developed via the consideration of phosphorus-containing agents and amino-carbon nanotube (A-CNT). One-pot functionalization method has been adopted to prepare functionalized CNTs via the reaction between A-CNT and different oxidation state phosphorus-containing agents, including chlorodiphenylphosphine (DPP-Cl), diphenylphosphinic chloride (DPP(O)-Cl), and diphenyl phosphoryl chloride (DPP(O₃)-Cl). These functionalized CNTs, DPP(O x )-A-CNTs ( x = 0, 1, 3), were, respectively, mixed with PBT to obtain the CNT-based polymer nanocomposites through a melt blending method. Scanning electron microscope observations demonstrated that DPP(O x )-A-CNT nanoadditives were homogeneously distributed within PBT matrix compared to A-CNT. The incorporation of DPP(O x )-A-CNT improved the thermal stability of PBT. Moreover, PBT/DPP(O₃)-A-CNT showed the highest crystallization temperature and tensile strength, due to the superior dispersion and interfacial interactions between DPP(O₃)-A-CNT and PBT. PBT/DPP(O)-A-CNT exhibited the best flame retardancy resulting from the excellent carbonization effect. The radicals generated from decomposed polymer were effectively trapped by DPP(O)-A-CNT, leading to the reduction of heat release rate, smoke production rate, carbon dioxide and carbon monoxide release during cone calorimeter tests.

Incretinomimetic and Insulinomimetic Effect of (2E)-N'-(1'-Naphthyl)-3,4,5-Trimethoxybenzohydrazide for Glycemic Homeostasis.

PubMed

Frederico, Marisa Jádna Silva; Mascarello, Alessandra; Castro, Allisson Jhonatan Gomes; Da Luz, Gabrielle; Altenhofen, Delsi; Mendes, Camila Pires; Leal, Paulo Cesar; Yunes, Rosendo Augusto; Nunes, Ricardo José; Silva, Fátima Regina Mena Barreto

2016-05-01

To characterize the role and the mechanism of action of (2E)-N'-(1'-naphthyl)-3,4,5-trimethoxybenzohydrazide (BZD) on incretin secretion, glucose uptake in skeletal muscle and α-glucosidase activity on intestine, targets for glucose homeostasis. It was assayed on glucose tolerance test (GTT) to analyze GLP-1 secretion and the activity of DPP-4 enzyme in vitro. In skeletal muscle, mechanism of action on glucose uptake was carried out by in vitro experiments. The activity of intestinal disaccharidases was performed after in vivo and in vitro experiments. The compound improved the glucose tolerance around 30%, 25%, and 20% at 15, 30, and 60 min, respectively and potentiated the sitagliptin effect, an inhibitor of the enzyme that removes GLP-1, about 50, 45, and 54% at 15, 30, and 60 min, respectively. Additionally, BZD did not modify the activity of DPP-4 enzyme. The acute effect of BZD on glucose uptake is mediated by increasing GLUT4 expression (around 140%) and its translocation to the plasma membrane in soleus muscle. The genomic effect as well as GLUT4 translocation involve the activation of PI-3K and MAPK pathways and require the microtubules integrity to the complete stimulatory effect of this compound on glucose uptake. Beyond, BZD acts in an alternative target to ameliorate glycaemia, intestinal disaccharidases. In a whole, these data point an incretino- and insulinomimetic effect of the compound for glycemic control. © 2015 Wiley Periodicals, Inc.

Synthesis, Characterization and TFT Characteristics of Diketopyrrolopyrrole Based Copolymer.

PubMed

Bathula, Chinna; Jeong, Seunghoon; Chung, Jeyon; Kang, Youngjong

2016-03-01

A novel diketopyrrolopyrrole (DPP) based low band gap polymer, poly[4,8-bis(triisopropylsilylethynyl) benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-[2,5-di-hexyl-3,6-dithiophen-2-ylpyrrolo[3,4-c]pyrrole-1,4-dione] (PTIPSBDT-DPP) is synthesized by Stille polymerization for use in thin film transistor (TFTs). The new polymer contain extended aromatic π-conjugated segments alternating with the DPP units and are designed to increase the free energy for charge generation to overcome current limitations in photocurrent generation. In this study we describe the synthesis, thermal stability, optical, electrochemical properties and TFT characteristics.

Role of the Diphosphine Chelate in Emissive, Charge-Neutral Iridium(III) Complexes.

PubMed

Liao, Jia-Ling; Devereux, Leon R; Fox, Mark A; Yang, Chun-Chieh; Chiang, Yu-Cheng; Chang, Chih-Hao; Lee, Gene-Hsiang; Chi, Yun

2018-01-12

A class of neutral tris-bidentate Ir III metal complexes incorporating a diphosphine as a chelate is prepared and characterized here for the first time. Treatment of [Ir(dppBz)(tht)Cl 3 ] (1, dppBz=1,2-bis(diphenylphosphino)benzene, tht=tetrahydrothiophene) with fppzH (3-trifluoromethyl-5-(2'-pyridyl)-1H-pyrazole) afforded the dichloride complexes, trans-(Cl,Cl)[Ir(dppBz)(fppz)Cl 2 ] (2) and cis-(Cl,Cl)[Ir(dppBz)(fppz)Cl 2 ] (3). The reaction of 3 with the dianionic chelate precursor, 5,5'-di(trifluoromethyl)-3,3'-bipyrazole (bipzH 2 ) or 5,5'-(1-methylethylidene)-bis(3-trifluoromethyl-1H-pyrazole) (mepzH 2 ), in DMF gave the tris-bidentate complex [Ir(dppBz)(fppz)(bipz)] (4) or [Ir(dppBz)(fppz)(mepz)] (5), respectively. In contrast, a hydride complex [Ir(dppBz)(fppz)(bipzH)H] (6) was isolated instead of 4 in protic solvent, namely: diethylene glycol monomethyl ether (DGME). All complexes 2-6 are luminescent in powder form and thin films where the dichlorides (2, 3) emit with maxima at 590-627 nm (orange) and quantum yields (QYs) up to 90 % whereas the tris-bidentate (4, 5) and hydride (6) complexes emit at 455-458 nm (blue) with QYs up to 70 %. Hybrid (time-dependent) DFT calculations showed considerable metal-to-ligand charge transfer contribution to the orange-emitting 2 and 3 but substantial ligand-centered 3 π-π* transition character in the blue-emitting 4-6. The dppBz does not participate in the radiative transitions in 4-6, but it provides the rigidity and steric bulk needed to promote the luminescence by suppressing the self-quenching in the solid state. Fabrication of an organic light-emitting diode (OLED) with dopant 5 gave a deep-blue CIE chromaticity of (0.16, 0.15). Superior blue emitters, which are vital in OLED applications, may be found in other neutral Ir III complexes containing phosphine chelates. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficacy of vildagliptin and sitagliptin in lowering fasting plasma glucose: Results of a randomized controlled trial.

PubMed

Göke, R; Eschenbach, P; Dütting, E D

2015-06-01

This study compared the efficacy of vildagliptin and sitagliptin in lowering fasting plasma glucose (FPG) as single-pill combinations (SPCs) with metformin. The randomized crossover, open-label, active-controlled study design assessed the FPG-lowering abilities of a vildagliptin/metformin (50/1000 mg twice daily) SPC compared with a sitagliptin/metformin (50/1000 mg twice daily) SPC after 2 weeks of treatment in 99 type 2 diabetes patients uncontrolled by stable metformin therapy (1000-2000 mg/day). The change in FPG from baseline to day 14 was significantly greater (P < 0.02, Wilcoxon) with vildagliptin [-21.9 mg/dL (SD 27.0)] than with sitagliptin [-14.5 mg/dL (SD 23.0)]. After 14 days of treatment, the mean FPG was 137.8 mg/dL (SD 28.5) with vildagliptin and 140.1mg/dL (SD 26.5) with sitagliptin (P < 0.05, Wilcoxon). Both of these DPP-4 inhibitors, given as SPCs twice daily with metformin, lowered FPG after 14 days of treatment. However, vildagliptin produced a significantly greater reduction in FPG vs baseline compared with sitagliptin, which may translate into clinical relevance. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

A possible usage of a CDK4 inhibitor for breast cancer stem cell-targeted therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Yu Kyeong; Lee, Jae Ho; Park, Ga-Young

2013-01-25

Highlights: ► A CDK4 inhibitor may be used for breast cancer stem cell-targeted therapy. ► The CDK4 inhibitor differentiated the cancer stem cell population (CD24{sup −}/CD44{sup +}) of MDA-MB-231. ► The differentiation of the cancer stem cells by the CDK4 inhibitor radiosensitized MDA-MB-231. -- Abstract: Cancer stem cells (CSCs) are one of the main reasons behind cancer recurrence due to their resistance to conventional anti-cancer therapies. Thus, many efforts are being devoted to developing CSC-targeted therapies to overcome the resistance of CSCs to conventional anti-cancer therapies and decrease cancer recurrence. Differentiation therapy is one potential approach to achieve CSC-targeted therapies.more » This method involves inducing immature cancer cells with stem cell characteristics into more mature or differentiated cancer cells. In this study, we found that a CDK4 inhibitor sensitized MDA-MB-231 cells but not MCF7 cells to irradiation. This difference appeared to be associated with the relative percentage of CSC-population between the two breast cancer cells. The CDK4 inhibitor induced differentiation and reduced the cancer stem cell activity of MDA-MB-231 cells, which are shown by multiple marker or phenotypes of CSCs. Thus, these results suggest that radiosensitization effects may be caused by reducing the CSC-population of MDA-MB-231 through the use of the CDK4 inhibitor. Thus, further investigations into the possible application of the CDK4 inhibitor for CSC-targeted therapy should be performed to enhance the efficacy of radiotherapy for breast cancer.« less

Clinical evidence and mechanistic basis for vildagliptin’s effect in combination with insulin

PubMed Central

Schweizer, Anja; Foley, James E; Kothny, Wolfgang; Ahrén, Bo

2013-01-01

Due to the progressive nature of type 2 diabetes, many patients need insulin as add-on to oral antidiabetic drugs (OADs) in order to maintain adequate glycemic control. Insulin therapy primarily targets elevated fasting glycemia but is less effective to reduce postprandial hyperglycemia. In addition, the risk of hypoglycemia limits its effectiveness and there is a concern of weight gain. These drawbacks may be overcome by combining insulin with incretin-based therapies as these increase glucose sensitivity of both the α- and β-cells, resulting in improved postprandial glycemia without the hypoglycemia and weight gain associated with increasing the dose of insulin. The dipeptidyl peptidase-IV (DPP-4) inhibitor vildagliptin has also been shown to protect from hypoglycemia by enhancing glucagon counterregulation. The effectiveness of combining vildagliptin with insulin was demonstrated in three different studies in which vildagliptin decreased A1C levels when added to insulin therapy without increasing hypoglycemia. This was established with and without concomitant metformin therapy. Furthermore, the effectiveness of vildagliptin appears to be greater when insulin is used as a basal regimen as opposed to being used to reduce postprandial hyperglycemia, since improvement in insulin secretion likely plays a minor role when relatively high doses of insulin are administered before meals. This article reviews the clinical experience with the combination of vildagliptin and insulin and discusses the mechanistic basis for the beneficial effects of the combination. The data support the use of vildagliptin in combination with insulin in general and, in line with emerging clinical practice, suggest that treating patients with vildagliptin, metformin, and basal insulin could be an attractive therapeutic option. PMID:23431062

Maternal deprivation decelerates postnatal morphological lung development of F344 rats.

PubMed

Hupa, Katharina Luise; Schmiedl, Andreas; Pabst, Reinhard; Von Hörsten, Stephan; Stephan, Michael

2014-02-01

Intensive medical care at premature born infants is often associated with separation of neonates from their mothers. Here, early artificial prolonged separation of rat pups from their dams (Maternal Deprivation, MD) was used to study potential impact on morphological lung maturation. Furthermore, we investigated the influence of an endogenous deficiency of the neuropeptide-cleaving dipeptidyl peptidase IV (DPP4), since the effects of MD are known to be partly mediated via neuropeptidergic effects, hypothesizing that MD will lead to a retardation of postnatal lung development, DPP4-dependendly. We used wild type and CD26/DPP4 deficient rats. For MD, the dam was placed each day into a separate cage for 2 h, while the pups remained in the nest on their own. Morphological lung maturation and cell proliferation at the postnatal days 7, 10, 14, and 21 were determined morphometrically. Maternally deprived wild types showed a retarded postnatal lung development compared with untreated controls in both substrains. During alveolarization, an increased thickness of alveolar septa and a decreased surface of septa about 50% were found. At the end of the morphological lung maturation, the surface of the alveolar septa was decreased at about 25% and the septal thickness remained increased about 20%. The proliferation rate was also decreased about 50% on day 14. However, the MD induced effects were less pronounced in DPP4-deficient rats, due to a significant deceleration already induced by DPP4-deficiency. Thus, MD as a model for postnatal stress experience influences remarkably postnatal development of rats, which is significantly modulated by the DPP4-system. Copyright © 2013 Wiley Periodicals, Inc.

Trelagliptin (SYR-472, Zafatek), novel once-weekly treatment for type 2 diabetes, inhibits dipeptidyl peptidase-4 (DPP-4) via a non-covalent mechanism

DOE PAGES

Grimshaw, Charles E.; Jennings, Andy; Kamran, Ruhi; ...

2016-06-21

Trelagliptin (SYR-472), a novel dipeptidyl peptidase-4 inhibitor, shows sustained efficacy by once-weekly dosing in type 2 diabetes patients. In this study, we characterized in vitro properties of trelagliptin, which exhibited approximately 4-and 12-fold more potent inhibition against human dipeptidyl peptidase-4 than alogliptin and sitagliptin, respectively, and >10,000-fold selectivity over related proteases including dipeptidyl peptidase-8 and dipeptidyl peptidase-9. Kinetic analysis revealed reversible, competitive and slow-binding inhibition of dipeptidyl peptidase-4 by trelagliptin (t 1/2 for dissociation ≈ 30 minutes). X-ray diffraction data indicated a non-covalent interaction between dipeptidyl peptidase and trelagliptin. Altogether, potent dipeptidyl peptidase inhibitionmay partially contribute to sustained efficacy ofmore » trelagliptin.« less

Trelagliptin (SYR-472, Zafatek), novel once-weekly treatment for type 2 diabetes, inhibits dipeptidyl peptidase-4 (DPP-4) via a non-covalent mechanism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grimshaw, Charles E.; Jennings, Andy; Kamran, Ruhi

Trelagliptin (SYR-472), a novel dipeptidyl peptidase-4 inhibitor, shows sustained efficacy by once-weekly dosing in type 2 diabetes patients. In this study, we characterized in vitro properties of trelagliptin, which exhibited approximately 4-and 12-fold more potent inhibition against human dipeptidyl peptidase-4 than alogliptin and sitagliptin, respectively, and >10,000-fold selectivity over related proteases including dipeptidyl peptidase-8 and dipeptidyl peptidase-9. Kinetic analysis revealed reversible, competitive and slow-binding inhibition of dipeptidyl peptidase-4 by trelagliptin (t 1/2 for dissociation ≈ 30 minutes). X-ray diffraction data indicated a non-covalent interaction between dipeptidyl peptidase and trelagliptin. Altogether, potent dipeptidyl peptidase inhibitionmay partially contribute to sustained efficacy ofmore » trelagliptin.« less

Combination treatment in the management of type 2 diabetes: focus on vildagliptin and metformin as a single tablet

PubMed Central

Halimi, Serge; Schweizer, Anja; Minic, Biljana; Foley, James; Dejager, Sylvie

2008-01-01

Vildagliptin is a potent and selective inhibitor of dipeptidyl peptidase-IV (DPP-4), orally active, that improves glycemic control in patients with type 2 diabetes (T2DM) primarily by enhancing pancreatic (α and β) islet function. Thus vildagliptin has been shown both to improve insulin secretion and to suppress the inappropriate glucagon secretion seen in patients with T2DM. Vildagliptin reduces HbA1c when given as monotherapy, without weight gain and with minimal hypoglycemia, or in combination with the most commonly prescribed classes of oral hypoglycemic drugs: metformin, a sulfonylurea, a thiazolidinedione, or insulin. Metformin, with a different mode of action not addressing β-cell dysfunction, has been used for about 50 years and still represents the universal first line therapy of all guidelines. However, given the multiple pathophysiological abnormalities in T2DM and the progressive nature of the disease, intensification of therapy with combinations is typically required over time. Recent guidelines imply that patients will require pharmacologic combinations much earlier to attain and sustain the increasingly stringent glycemic targets, with careful drug selection to avoid unwanted adverse events, especially hypoglycemia. The combination of metformin and vildagliptin offers advantages when compared to currently used combinations with additive efficacy and complimentary mechanisms of action, since it does not increase the risk of hypoglycemia and does not promote weight gain. Therefore, by specifically combining these agents in a single tablet, there is considerable potential to achieve better blood glucose control and to improve compliance to therapy. PMID:18827867

PTP1B, α-glucosidase, and DPP-IV inhibitory effects for chromene derivatives from the leaves of Smilax china L.

PubMed

Zhao, Bing Tian; Le, Duc Dat; Nguyen, Phi Hung; Ali, Md Yousof; Choi, Jae-Sue; Min, Byung Sun; Shin, Heung Mook; Rhee, Hae Ik; Woo, Mi Hee

2016-06-25

Two new flavonoids, bismilachinone (11) and smilachinin (14), were isolated from the leaves of Smilax china L. together with 14 known compounds. Their structures were elucidated using spectroscopic methods. The PTP1B, α-glucosidase, and DPP-IV inhibitory activities of compounds 1-16 were evaluated at the molecular level. Among them, compounds 4, 7, and 10 showed moderate DPP-IV inhibitory activities with IC50 values of 20.81, 33.12, and 32.93 μM, respectively. Compounds 3, 4, 6, 11, 12, and 16 showed strong PTP1B inhibitory activities, with respective IC50 values of 7.62, 10.80, 0.92, 2.68, 9.77, and 24.17 μM compared with the IC50 value for the positive control (ursolic acid: IC50 = 1.21 μM). Compounds 2-7, 11, 12, 15, and 16 showed potent α-glucosidase inhibitory activities, with respective IC50 values of 8.70, 81.66, 35.11, 35.92, 7.99, 26.28, 11.28, 62.68, 44.32, and 70.12 μM. The positive control, acarbose, displayed an IC50 value of 175.84 μM. In the kinetic study for the PTP1B enzyme, compounds 6, 11, and 12 displayed competitive inhibition with Ki values of 3.20, 8.56, and 5.86 μM, respectively. Compounds 3, 4, and 16 showed noncompetitive inhibition with Ki values of 18.75, 5.95, and 22.86 μM, respectively. Molecular docking study for the competitive inhibitors (6, 11, and 12) radically corroborates the binding affinities and inhibition of PTP1B enzymes. These results indicated that the leaves of Smilax china L. may contain compounds with anti-diabetic activity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Dipeptidyl peptidase-II from probiotic Pediococcus acidilactici: Purification and functional characterization.

PubMed

Gandhi, Dimpi; Chanalia, Preeti; Attri, Pooja; Dhanda, Suman

2016-12-01

Dipeptidylpeptidase-II (DPP-II, E.C. 3.4.14.2), an exopeptidase was purified 15.4 fold with specific activity and yield of 15.4U/mg/mL and 14.68% respectively by a simple two step procedure from a probiotic Pediococcus acidilactici. DPP-II is 38.7KDa homodimeric serine peptidase with involvement of His and subunit mass of 18.9KDa. The enzyme exhibited optimal activity at pH 7.0 and 37°C with activation energy of 24.97kJ/mol. The enzyme retained more than 90% activity upto 50°C thus adding industrial importance. DPP-II hydrolysed Lys-Ala-4mβNA with K M of 50μM and V max of 30.8nmol/mL/min. In-silico characterization studies of DPP-II on the basis of peptide fragments obtained by MALDI-TOF revealed an evolutionary relationship between DPP-II of prokaryotes and phosphate binding proteins. Secondary and three-dimensional structure of enzyme was also deduced by in-silico approach. Functional studies of DPP-II by TLC and HPLC-analysis of collagen degraded products revealed that enzyme action released free amino acids and other metabolites. Microscopic and SDS-PAGE analysis of enzyme treated analysis of chicken's chest muscle (meat) hydrolysis revealed change and hydrolysis of myofibrils. This may affect the flavor and texture of meat thereby suggesting its role in meat tenderization. Being a protein of LAB (Lactic acid bacteria), it is also expected to be safe. Copyright © 2016 Elsevier B.V. All rights reserved.

Bi-diketopyrrolopyrrole (Bi-DPP) as a novel electron accepting compound in low band gap π-conjugated donor–acceptor copolymers/oligomers

PubMed Central

Ahner, Johannes; Nowotny, Jürgen; Schubert, Ulrich S.; Hager, Martin D.

2017-01-01

Abstract The synthesis and characterization of a novel 2,5-diketopyrrolo[3,4-c]pyrrole(DPP)-based accepting building block with the scheme DPP-neutral small linker-DPP (Bi-DPP) is presented, which was utilized as electron accepting moiety for low band gap π-conjugated donor–acceptor copolymers as well as for a donor–acceptor small molecule. The electron accepting moiety Bi-DPP was prepared via a novel synthetic pathway by building up two DPP moieties step by step simultaneously starting from a neutral phenyl core unit. Characterization of the synthesized oligomeric and polymeric materials via cyclic voltammetry afford LUMO energy levels from −3.49 to −3.59 eV as well as HOMO energy levels from −5.07 to −5.34 eV resulting in low energy band gaps from 1.52 to 1.81 eV. Spin coating of the prepared donor–acceptor oligomers/polymers resulted in well-defined films. Moreover, UV–vis measurements of the investigated donor–acceptor systems showed a broad absorption over the whole visible region. It is demonstrated that Bi-DPP as an electron accepting moiety in donor–acceptor systems offer potential properties for organic solar cell devices. PMID:29491794

Assessing intravascular volume by difference in pulse pressure in pigs submitted to graded hemorrhage.

PubMed

Pestel, Gunther J; Hiltebrand, Luzius B; Fukui, Kimiko; Cohen, Delphine; Hager, Helmut; Kurz, Andrea M

2006-10-01

We assessed changes in intravascular volume monitored by difference in pulse pressure (dPP%) after stepwise hemorrhage in an experimental pig model. Six pigs (23-25 kg) were anesthetized (isoflurane 1.5 vol%) and mechanically ventilated to keep end-tidal CO2 (etCO2) at 35 mmHg. A PA-catheter and an arterial catheter were placed via femoral access. During and after surgery, animals received lactated Ringer's solution as long as they were considered volume responders (dPP>13%). Then animals were allowed to stabilize from the induction of anesthesia and insertion of catheters for 30 min. After stabilization, baseline measurements were taken. Five percent of blood volume was withdrawn, followed by another 5%, and then in 10%-increments until death from exsanguination occurred. After withdrawal of 5% of blood volume, all pigs were considered volume responders (dPP>13%); dPP rose significantly from 6.1+/-3.3% to 19.4+/-4.2%. The regression analysis of stepwise hemorrhage revealed a linear relation between blood loss (hemorrhage in %) and dPP (y=0.99*x+14; R2=0.7764; P<.0001). In addition, dPP was the only parameter that changed significantly between baseline and a blood loss of 5% (P<0.01), whereas cardiac output, stroke volume, heart rate, MAP, central venous pressure, pulmonary artery occlusion pressure, and systemic vascular resistance, respectively, remained unchanged. We conclude that in an experimental hypovolemic pig model, dPP correlates well with blood loss.

Dipeptidyl Peptidase 10 (DPP10789): A Voltage Gated Potassium Channel Associated Protein Is Abnormally Expressed in Alzheimer's and Other Neurodegenerative Diseases

PubMed Central

Gai, Wei-Ping; Abbott, Catherine A.

2014-01-01

The neuropathological features associated with Alzheimer's disease (AD) include the presence of extracellular amyloid-β peptide-containing plaques and intracellular tau positive neurofibrillary tangles and the loss of synapses and neurons in defined regions of the brain. Dipeptidyl peptidase 10 (DPP10) is a protein that facilitates Kv4 channel surface expression and neuronal excitability. This study aims to explore DPP10789 protein distribution in human brains and its contribution to the neurofibrillary pathology of AD and other tauopathies. Immunohistochemical analysis revealed predominant neuronal staining of DPP10789 in control brains, and the CA1 region of the hippocampus contained strong reactivity in the distal dendrites of the pyramidal cells. In AD brains, robust DPP10789 reactivity was detected in neurofibrillary tangles and plaque-associated dystrophic neurites, most of which colocalized with the doubly phosphorylated Ser-202/Thr-205 tau epitope. DPP10789 positive neurofibrillary tangles and plaque-associated dystrophic neurites also appeared in other neurodegenerative diseases such as frontotemporal lobar degeneration, diffuse Lewy body disease, and progressive supranuclear palsy. Occasional DPP10789 positive neurofibrillary tangles and neurites were seen in some aged control brains. Western blot analysis showed both full length and truncated DPP10789 fragments with the later increasing significantly in AD brains compared to control brains. Our results suggest that DPP10789 is involved in the pathology of AD and other neurodegenerative diseases. PMID:25025038

Probing charge transfer complex states in organic solar cells using photocurrent spectroscopy

NASA Astrophysics Data System (ADS)

Moghe, Dhanashree; Adil, Danish; Kanimozhi, Catherine; Dutta, Gitesh; Patil, Satish; Guha, Suchismita

2013-03-01

Diketopyrrolopyrrole (DPP) containing copolymers-fullerene blends have gained a lot of interest in organic optoelectronics with a great potential in organic photovoltaics (OPVs). The interfacial charge transfer complex (CTC) states formed in donor-acceptor blended OPVs play a major role in the overall efficiency of the device. We investigate the spectral photocurrent characteristics of five DPP based copolymers; two of them being benzothiadiazole and carbazole -based statistical copolymers of DPP. These systems provide a wide range of bandgap energies ranging from ~ 1.4 to 1.7 eV. We use Fourier transform photocurrent spectroscopy (FTPS) and monochromatic photocurrent (PC) to identify the CTC states in these DPP copolymer -fullerene blends. The stability of the CTC state is found to be dependent on the band gap energy difference between the donor copolymer and the acceptor. We support our inferences from theoretical results obtained using density-functional theory (DFT) and time-dependent DFT for two DPP based copolymers The theoretical calculations reveal a higher contribution of the CTC states to the lowest excited state in the phenyl-based DPP monomer, which has a larger bandgap energy compared to the thiophene-based DPP system, in the presence of a fullerene molecule.

Evaluation of protein C and protein S levels in patients with diabetes mellitus receiving therapy with statins and ACE inhibitors or angiotensin II receptor blockers.

PubMed

Aktaş, Şerife; Uçak, Sema; Kurt, Fatma; Taşdemir, Mehmet; Kutlu, Orkide; Eker, Pınar

2018-01-01

To evaluate protein C, protein S level in patients with diabetes mellitus receiving statin and ACE inhibitor/ARB therapy. 95 patients were included in the study and divided into four groups depending on the use of statin and ACE inhibitor/ARB therapy. Group 1 comprised of patients receiving statin therapy (n = 15), Group 2 comprised of patients receiving ACE inhibitor/ARB therapy (n = 31), Group 3 comprised of patients receiving statin and ACE inhibitor/ARB therapy (n = 23), and Group 4 comprised of patients who did not receive either statin or ACE inhibitor/ARB therapy (n = 26). These four groups were compared with respect to protein C, protein S, fibrinogen, D-dimer, INR, and aPTT levels. There were statistically significant differences with respect to protein C levels. Group 1 and group 2 had higher protein C levels compared with group 4. (p < .01). Similarly, Group 3 had higher protein C levels compared with group 4. (p < .01). There was no significant difference between the groups with respect to protein S, INR, aPTT, and D-dimer levels. Diabetic patients receiving statin or ACE inhibitor/ARB therapy had higher protein C levels. Use of statin and ACE inhibitor/ARB therapy in diabetic patients decrease hypercoagulability and therefore could reduce the occurrence of cardiovascular events. Copyright © 2017 Elsevier B.V. All rights reserved.

Potential use of bitter melon (Momordica charantia) derived compounds as antidiabetics: In silico and in vivo studies.

PubMed

Elekofehinti, Olusola Olalekan; Ariyo, Esther Opeyemi; Akinjiyan, Moses Orimoloye; Olayeriju, Olanrewaju Sam; Lawal, Akeem Olalekan; Adanlawo, Isaac Gbadura; Rocha, Joao Batista Teixeira

2018-05-12

Momordica charantia (bitter lemon) belongs to the cucurbitaceae family which has been extensively used in traditional medicines for the cure of various ailments such as cancer and diabetes. The underlying mechanism of M. charantia to maintain glycemic control was investigated. GLP-1 and DPP-4 gene modulation by M. charantia (5-20% inclusion in rats diet) was investigated in vivo by RT-PCR and possible compounds responsible for diabetic action predicted through in silico approach. Phytochemicalss previously characterized from M. charantia were docked into glucacon like peptide-1 receptor (GLP-1r), dipeptidyl peptidase (DPP4) and Takeda-G-protein-receptor-5 (TGR5) predicted using Autodock Vina. The results of the in silico suggests momordicosides D (ligand for TGR5), cucurbitacin (ligand for GLP-1r) and charantin (ligand for DPP-4) as the major antidiabetic compounds in bitter lemon leaf. M. charantia increased the expression of GLP-1 by about 295.7% with concomitant decreased in expression of DPP-4 by 87.2% with 20% inclusion in rat's diet. This study suggests that the mechanism underlying the action of these compounds is through activation of TGR5 and GLP-1 receptor with concurrent inhibition of DPP4. This study confirmed the use of this plant in diabetes management and the possible bioactive compounds responsible for its antidiabetic property are charantin, cucurbitacin and momordicoside D and all belong to the class of saponins. Copyright © 2018 Elsevier B.V. All rights reserved.

The Evaluation of Dipeptidyl Peptidase (DPP)-IV, α-Glucosidase and Angiotensin Converting Enzyme (ACE) Inhibitory Activities of Whey Proteins Hydrolyzed with Serine Protease Isolated from Asian Pumpkin (Cucurbita ficifolia).

PubMed

Konrad, Babij; Anna, Dąbrowska; Marek, Szołtysik; Marta, Pokora; Aleksandra, Zambrowicz; Józefa, Chrzanowska

2014-01-01

In the present study, whey protein concentrate (WPC-80) and β-lactoglobulin were hydrolyzed with a noncommercial serine protease isolated from Asian pumpkin ( Cucurbita ficifolia ). Hydrolysates were further fractionated by ultrafiltration using membranes with cut-offs equal 3 and 10 kDa. Peptide fractions of molecular weight lower than 3 and 3-10 kDa were further subjected to the RP-HPLC. Separated preparations were investigated for their potential as the natural inhibitors of dipeptidyl peptidase (DPP-IV), α-glucosidase and angiotensin converting enzyme (ACE). WPC-80 hydrolysate showed higher inhibitory activities against the three tested enzymes than β-lactoglobulin hydrolysate. Especially high biological activities were exhibited by peptide fractions of molecular weight lower than 3 kDa, with ACE IC50 <0.64 mg/mL and DPP-IV IC50 <0.55 mg/mL. This study suggests that peptides generated from whey proteins may support postprandial glycemia regulation and blood pressure maintenance, and could be used as functional food ingredients in the diet of patients with type 2 diabetes.

Enhanced effects by 4-phenylbutyrate in combination with RTK inhibitors on proliferation in brain tumor cell models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marino, Ana-Maria; Center for Molecular Medicine CMM, Karolinska University Hospital, Stockholm; Sofiadis, Anastasios

2011-07-22

Highlights: {yields} The histone deacetylase inhibitor 4-phenylbutyrate substantially enhance efficacy of the receptor tyrosine kinase inhibitors gefitinib or vandetanib in glioma and medulloblastoma cell lines. {yields} Cell death increases and clonogenic survival is reduced in the combination treatments, over mono-therapy. {yields} Combination treatments with these drugs may improve clinical outcome for cancer therapy. -- Abstract: We have investigated in vitro effects of anticancer therapy with the histone deacetylase inhibitor (HDACi) 4-phenylbutyrate (4-PB) combined with receptor tyrosine kinase inhibitors (RTKi) gefitinib or vandetanib on the survival of glioblastoma (U343MGa) and medulloblastoma (D324Med) cells. In comparison with individual effects of these drugs,more » combined treatment with gefitinib/4-PB or vandetanib/4-PB resulted in enhanced cell killing and reduced clonogenic survival in both cell lines. Our results suggest that combined treatment using HDACi and RTKi may beneficially affect the outcome of cancer therapy.« less

Identification of dipeptidyl peptidase-IV inhibitory peptides from mare whey protein hydrolysates.

PubMed

Song, J J; Wang, Q; Du, M; Ji, X M; Mao, X Y

2017-09-01

Inhibition of dipeptidyl peptidase-IV (DPP-IV) activity is a promising strategy for treatment of type 2 diabetes. In the current study, DPP-IV inhibitory peptides were identified from mare whey protein hydrolysates obtained by papain. The results showed that all the mare whey protein hydrolysates obtained at various hydrolysis durations possessed more potent DPP-IV inhibitory activity compared with intact whey protein. The 4-h hydrolysates showed the greatest DPP-IV inhibitory activity with half-maximal inhibitory concentration of 0.18 mg/mL. The 2 novel peptides from 4-h hydrolysate fractions separated by successive chromatographic steps were characterized by liquid chromatography-electrospray ionization tandem mass spectrometry. The novel peptides Asn-Leu-Glu-Ile-Ile-Leu-Arg and Thr-Gln-Met-Val-Asp-Glu-Glu-Ile-Met-Glu-Lys-Phe-Arg, which corresponded to β-lactoglobulin 1 f(71-77) and β-lactoglobulin 1 f(143-155), demonstrated DPP-IV inhibitory activity with half-maximal inhibitory concentrations of 86.34 and 69.84 μM, respectively. The DPP-IV inhibitory activity of the 2 peptides was retained or even improved after simulated gastrointestinal digestion in vitro. Our findings indicate that mare whey protein-derived peptides may possess potential as functional food ingredients in the management of type 2 diabetes. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Reliability of techniques used in the diagnosis of canine visceral leishmaniasis by the national control program in Brazil: A survey in an area of recent transmission.

PubMed

Belo, Vinícius Silva; Gregório, Eliana Aparecida; Teixeira-Neto, Rafael Gonçalves; da Rocha Lima, Ana Cristina Vianna Mariano; Pereira, Agnes Antônia Sampaio; Marcelino, Andreza Pain; Paz, Gustavo Fontes; da Silva, Eduardo Sérgio

2017-10-01

One of the key components of the Brazilian Program for the Control of Visceral Leishmaniasis (PCLV) is the euthanasia of Leishmania-infected canine reservoirs, the detection of which depends on a screening procedure involving a Dual Path Platform ® (DPP) immunoassay and a confirmatory enzyme-linked immunosorbent assay (ELISA). The aims of the present study were to evaluate the reliability of these techniques in a region of recent transmission of canine VL, to follow up the seroconversion 3-4 months after the initial diagnosis of DPP reactive but ELISA indeterminate or non-reactive dogs, and to identify the species of Leishmania in circulation in the area. Each animal was submitted to DPP under field conditions, performed by municipal health workers using peripheral blood (DPP-field), to DPP under laboratory conditions using serum (DPP-lab) and to ELISA using serum. The agreements between the tests were determined using McNemar's χ 2 test, Cohen's kappa coefficient (k) at the 95% confidence interval and prevalence-adjusted bias-adjusted kappa (PABAK). Of the 1130 dogs examined, 74.2% were non-reactive in all three tests applied. Based on the PCLV positive-infection criterion, seroprevalence was 8.9% (101/1130) with 83.2% (84/101) of infected animals showing reactivity in all three tests while 7.8% (8/101) were reactive in DPP-field and ELISA and 8.9% (9/101) in DPP-lab and ELISA. The proportions of disagreements were substantial in all comparisons. Inter-rater reliability between DPP-field and ELISA (k=0.55; PABAK=0.78) and DPP-lab and ELISA (k=0.59; PABAK=0.81) were considered moderate, while that between DPP-field and DPP-lab (k=0.61; PABAK=0.79) was classified as marginally good. The proportion of seroconversions in DPP reactive animals that were initially ELISA indeterminate was significantly higher than in those that were DPP reactive but initially ELISA non-reactive. Restriction fragment length polymorphism analysis revealed the presence of Leishmania infantum, the etiologic agent of VL, in bone marrow samples from VL-infected animals. Our data showed that the techniques and protocols currently employed in the PCLV screening approach are not entirely reliable. Further consideration should be given to monitoring dogs with undetermined results in ELISA and a better training should be provided for health workers responsible for performing DPP tests applied under field conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Tuning the Photophysical Properties of Ru(II) Monometallic and Ru(II),Rh(III) Bimetallic Supramolecular Complexes by Selective Ligand Deuteration.

PubMed

Wagner, Alec T; Zhou, Rongwei; Quinn, Kevan S; White, Travis A; Wang, Jing; Brewer, Karen J

2015-07-02

A series of three new complexes of the design [(TL)2Ru(BL)](2+), two new complexes of the design [(TL)2Ru(BL)Ru(TL)2](4+), and three new complexes of the design [(TL)2Ru(BL)RhCl2(TL)](3+) (TL = bpy or d8-bpy; BL = dpp or d10-dpp; TL = terminal ligand; BL = bridging ligand; bpy = 2,2'-bipyridine; dpp = 2,3-bis(2-pyridyl)pyrazine) were synthesized and the (1)H NMR spectroscopy, electrochemistry, electronic absorbance spectroscopy, and photophysical properties studied. Incorporation of deuterated ligands into the molecular architecture simplifies the (1)H NMR spectra, allowing for complete (1)H assignment of [(d8-bpy)2Ru(dpp)](PF6)2 and partial assignment of [(bpy)2Ru(d10-dpp)](PF6)2. The electrochemistry for the deuterated and nondeuterated species showed nearly identical redox properties. Electronic absorption spectroscopy of the deuterated and nondeuterated complexes are superimposable with the lowest energy transition being Ru(dπ) → BL(π*) charge transfer in nature (BL = dpp or d10-dpp). Ligand deuteration impacts the excited-state properties with an observed increase in the quantum yield of emission (Φ(em)) and excited-state lifetime (τ) of the Ru(dπ) → d10-dpp(π*) triplet metal-to-ligand charge transfer ((3)MLCT) excited state when dpp is deuterated, and a decrease in the rate constant for nonradiative decay (knr). Choice of ligand deuteration between bpy and dpp strongly impacts the observed photophysical properties with BL = d10-dpp complexes showing an enhanced Φ(em) and τ, providing further support that the lowest electronic excited state populated via UV or visible excitation is the photoactive Ru(dπ) → dpp(π*) CT excited state. The Ru(II),Rh(III) complex incorporating the deuterated BL shows increased hydrogen production compared to the variants incorporating the protiated BL, while demonstrating identical dynamic quenching behaviors in the presence of sacrificial electron donor.

Active phytochemicals of Pueraria tuberosa for DPP-IV inhibition: in silico and experimental approach.

PubMed

Srivastava, Shivani; Shree, Priya; Tripathi, Yamini Bhusan

2017-01-01

We had earlier reported that the extract of Pueraria tuberosa significantly inhibits DPP-IV enzyme, resulting in glucose tolerance response in rats. In this study, we have explored the active phytochemicals responsible for this potential. The results have been validated in both fasting and postprandial states in the plasma of normal rats and also in fasting blood and intestinal homogenates of diabetic models. Pueraria tuberosa water extract (PTWE) was administered to normal Charles Foster rats for 35 days and to diabetic model (65 mg/kg bw) for 10 days. After treatments, oral glucose tolerance test (OGTT) and insulin was done for 90 min, and the changes in the levels of GLP-1, GIP, and DPP-IV activities were monitored in fasting and postprandial states. In the case of the diabetic model, DPP-IV activity was measured in intestinal homogenate and basal insulin in plasma. The components of PTWE were analyzed via HPLC-MS based on their chemical formula, molecular mass, and retention time. Using the molecular docking study, we have selected the top five components having strong binding energy with DPP-IV. The increase in secretion of GLP-1 and GIP was significantly higher in the postprandial state when compared to fasting condition. GLP-1 plasma concentration increased by 5.8 and 2.9 folds and GIP increased by 8.7 and 2.4 folds in PTWE and control rats, respectively. In contrast, the postprandial decrease in DPP-IV specific activities was recorded at 2.3 and 1.4 folds. The response in OGTT and insulin was also consistent with these changes. In comparison to diabetic controls, PTWE-administered rats showed decreased DPP-IV activity in the intestine, leading to enhanced basal insulin concentration. Through molecular docking, we found Puerarone and Robinin to be the most potential phytochemicals of PTWE for DPP-IV inhibition. Binding energy (kcal/mol) and dissociation constant (pM) of Robinin with DPP-IV protein were found to be 7.543 and 2,957,383.75, respectively. For Puerarone, it was 7.376 and 3,920,309, respectively. Thus, this study provides the novel active components that contribute to the DPP-IV inhibitory property of PTWE.

Real-life efficacy and safety of vildagliptin compared with sulfonylureas as add-on to metformin in patients with type 2 diabetes mellitus in Germany.

PubMed

Göke, R; Gruenberger, J B; Bader, G; Dworak, M

2014-05-01

Metformin is an established first-line treatment for type 2 diabetes mellitus (T2DM) patients, but intensification of oral anti-diabetes therapy is usually required over time. A large observational study of 45,868 T2DM patients in 27 countries (EDGE) was conducted to compare the effectiveness and safety of vildagliptin as add-on therapy to another oral anti-diabetes drug (OAD) vs other dual OAD combinations. This report presents results from a post-hoc analysis of patients in Germany who received vildagliptin or a sulfonylurea (SU) in combination with metformin. Patients inadequately controlled with monotherapy became eligible only after the add-on treatment was finalized. Patients included were assigned to receive either vildagliptin or another OAD (SUs, thiazolidinediones, glinides, α-glucosidase inhibitors, or metformin; DPP-4 inhibitors or glucagon-like peptide-1 [GLP-1] mimetics/analogs were excluded). The primary end-point was the proportion of patients achieving a reduction in HbA1c >0.3% without peripheral edema, hypoglycemia, discontinuation due to gastrointestinal event, or weight gain ≥5%. Of 8887 patients enrolled in Germany, 6439 received vildagliptin and 971 received SUs as add-on to metformin. The primary end-point was reached in 34.9% and 29.6% of patients in the vildagliptin and SU groups, respectively, with an unadjusted odds ratio of 1.27 (95% CI = 1.09, 1.47; p = 0.001). HbA1c decreased in both cohorts from baseline (-0.7% with vildagliptin vs -0.5% with SUs), with a mean between-group difference of -0.2% (95% CI = -0.22, -0.09). The number of hypoglycemic events was 4-fold higher in the SU group than in the vildagliptin group (vildagliptin = 0.11%; SU = 0.41%). In a real-life setting, vildagliptin was associated with a numerically greater reduction in HbA1c, less hypoglycemia, and more patients reaching target HbA1c without hypoglycemia or weight gain compared with SUs. Open-label design and under reporting of adverse events are limitations of this post hoc analysis.

The Effects of Aerobic Exercises and 25(OH) D Supplementation on GLP1 and DPP4 Level in Type II Diabetic Patients.

PubMed

Rahimi, Naser; Samavati Sharif, Mohammad Ali; Goharian, Amir Reza; Pour, Ali Heidarian

2017-01-01

The purpose of this study was to investigate the effects of an 8-week aerobic exercise and supplementation of 25(OH)D3 on GLP1 and DDP4 levels in men with type II diabetes. In this semiexperimental research, among 40-60-year-old men with type II diabetes who were referred to the diabetic center of Isabn-E Maryam hospital in Isfahan; of whom, 48 patients were voluntarily accepted and then were randomly divided into 4 groups: aerobic exercise group, aerobic exercise with 25(OH) D supplement group, 25(OH) D supplement group, and the control group. An aerobic exercise program was conducted for 8 weeks (3 sessions/week, each session 60 to75 min with 60-80% HRmax). The supplement user group received 50,000 units of oral Vitamin D once weekly for 8 weeks. The GLP1, DPP4, and 25(OH) D levels were measured before and after the intervention. At last, the data were statistically analyzed using the ANCOVA and post hoc test of least significant difference. The results of ANCOVA showed a significant difference between the GLP1 and DPP4 levels in aerobic exercise with control group while these changes were not statistically significant between the 25(OH) D supplement group with control group ( P < 0.05). Aerobic exercises have resulted an increase in GLP1 level and a decrease in DPP4 level. However, consumption of Vitamin D supplement alone did not cause any changes in GLP1and DPP4 levels but led to an increase in 25-hydroxy Vitamin D level.

Diabetes and Ramadan: An Update On Use of Glycemic Therapies During Fasting

PubMed Central

Ahmed, Mohamed H.; Abdu, Tarig A. M.

2011-01-01

The fasting of Ramadan is observed by a large proportion of Muslims with diabetes. Recommendations for the management of diabetes during Ramadan were last published in 2005 by the American Diabetes Association. Several studies in this field have since been published, some addressing the use of new pharmacological agents in managing diabetes during Ramadan. The incritin memetics are potentially safe during Ramadan; the DPP4 inhibitors vildagliptin and sitagliptin provide an effective and safe therapeutic option, administered either alone or in combination with metformin or sulfonylureas. There are no published studies on the use of GLP-1 receptor agonists during Ramadan. Among the sulfonylureas, gliclazide MR (modified release) and glimepride can be safely used during Ramadan, but glibenclamide should be avoided due to the associated risk of hypoglycemia. In selected patients with type 1 and type 2 diabetes, the long-acting insulin analogues glargine and detemir, as well as the premixed insulin analogues, can be used with minimal risk of metabolic derangement or hypoglycemia; the risk is higher in type 1 diabetes. Insulin pumps can potentially empower patients with diabetes and enable safe fasting during the month of Ramadan. Further clinical trials are needed to evaluate the safety and efficacy of new antidiabetic agents and new diabetes-related technologies during Ramadan. PMID:21727749

Diabetes and Ramadan: an update on use of glycemic therapies during fasting.

PubMed

Ahmed, Mohamed H; Abdu, Tarig A M

2011-01-01

The fasting of Ramadan is observed by a large proportion of Muslims with diabetes. Recommendations for the management of diabetes during Ramadan were last published in 2005 by the American Diabetes Association. Several studies in this field have since been published, some addressing the use of new pharmacological agents in managing diabetes during Ramadan. The incritin memetics are potentially safe during Ramadan; the DPP4 inhibitors vildagliptin and sitagliptin provide an effective and safe therapeutic option, administered either alone or in combination with metformin or sulfonylureas. There are no published studies on the use of GLP-1 receptor agonists during Ramadan. Among the sulfonylureas, gliclazide MR (modified release) and glimepride can be safely used during Ramadan, but glibenclamide should be avoided due to the associated risk of hypoglycemia. In selected patients with type 1 and type 2 diabetes, the long-acting insulin analogues glargine and detemir, as well as the premixed insulin analogues, can be used with minimal risk of metabolic derangement or hypoglycemia; the risk is higher in type 1 diabetes. Insulin pumps can potentially empower patients with diabetes and enable safe fasting during the month of Ramadan. Further clinical trials are needed to evaluate the safety and efficacy of new antidiabetic agents and new diabetes-related technologies during Ramadan.

Evidence for an interaction between leptin, T cell costimulatory antigens CD28, CTLA-4 and CD26 (dipeptidyl peptidase IV) in BCG-induced immune responses of leptin- and leptin receptor-deficient mice.

PubMed

Rüter, Jens; Hoffmann, Torsten; Demuth, Hans-Ulrich; Moschansky, Petra; Klapp, Burghard F; Hildebrandt, Martin

2004-06-01

We assessed changes of the enzyme dipeptidyl peptidase IV (DPP IV, CD26) in the context of leptin or leptin receptor deficiency. C57BL/6 mice, Leptin-deficient mice (ob/ob mice, B6.V-Lep) and Leptin-receptor-deficient mice (db/db mice, B6.Cg-m+/+Lepr) were infected with B. Calmette-Guerin (BCG) and sacrificed three days later. DPP IV activity in serum was higher in ob/ob mice and in db/db mice than in wild-type mice. The expression of DPP IV/CD26 on splenocytes was higher in ob/ob mice than in wild-type animals, and lower in db/db mice, and decreased upon stimulation with BCG in ob/ob mice only. Several T cell antigens including CTLA-4 were expressed aberrantly in ob/ob and in db/db mice. Our observations provide evidence for a relationship between DPP IV and leptin.

Shifting the paradigm in Dirofilaria immitis prevention: blocking transmission from mosquitoes to dogs using repellents/insecticides and macrocyclic lactone prevention as part of a multimodal approach.

PubMed

McCall, John W; Varloud, Marie; Hodgkins, Elizabeth; Mansour, Abdelmoneim; DiCosty, Utami; McCall, Scott; Carmichael, James; Carson, Ben; Carter, Justin

2017-11-09

This study assessed the influence of a topical ectoparasiticide (dinotefuran-permethrin-pyriproxyfen, DPP, Vectra® 3D, Ceva Animal Health) combined with a macrocyclic lactone (milbemycin oxime, MBO, Interceptor®, Virbac) on transmission of heartworm L3 from mosquitoes to dogs and subsequent development of worms in treated dogs exposed to infected mosquitoes. Thirty-two beagle dogs were allocated to four groups of eight: Group 1, untreated controls; Group 2, treated topically with DPP on Day 0; Group 3, treated orally with MBO on Day 51; and Group 4, treated with DPP on Day 0 and MBO on Day 51. Dogs were exposed under sedation for 1 h to Dirofilaria immitis (JYD-34)-infected Aedes aegypti on Days 21 and 28. At the end of each exposure, mosquitoes were classified as live, moribund, or dead and engorged or non-engorged. Live or moribund mosquitoes were incubated for daily survival assessment for 3 days. Mosquitoes were dissected before and after exposure to estimate the number of L3 transmitted to each dog. Dogs were necropsied 148 to 149 days postinfection. A total of 418 mosquitoes fed on the 16 dogs in Groups 1 and 3, while only 6 fed on the 16 DPP-treated dogs in Groups 2 and 4. Mosquito anti-feeding (repellency) effect in Groups 2 and 4 was 98.1 and 99.1%, respectively. The estimated numbers of L3 transmitted to controls, DPP-treated, MBO-treated and DPP + MBO-treated dogs were 76, 2, 78, and 1, respectively. No heartworms were detected in any of the DPP + MBO-treated dogs (100% efficacy), while 8 out of 8 were infected in the control group (range, 21-66 worms per dog), 8 out of 8 were infected in the MBO-treated group (58% efficacy), and 3 out of 8 were infected in the DPP-treated group (96% efficacy). DPP repelled and killed most mosquitoes that were capable of transmitting heartworm L3 to dogs. The "Double Defense" protocol of DPP + MBO had better efficacy for protecting dogs against heartworm transmission and infection than MBO alone. This added DPP benefit is more pronounced when macrocyclic lactone-resistant strains of heartworms are involved or lack of compliance in macrocyclic lactone administration is known or suspected.

A Systematic Approach to Solvent Selection Based on Cohesive Energy Densities in a Molecular Bulk Heterojunction System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, Bright; Tamayo, Arnold; Duong, Duc T.

The solubilities of 3,6-bis(5-(benzofuran-2-yl)thiophen-2-yl)-2,5-bis(2-ethylhexyl)pyrrolo[3,4-c]pyrrole-1,4-dione (DPP(TBFu)₂) and [6,6]-phenyl-C₇₁-butyric acid methyl ester (PC₇₁BM) in a series of solvents are measured, and this data is used to calculate the Hansen solubility parameters of the two materials. The dispersion, polar, and H-bonding parameters of DPP(TBFu)₂ and PC₇₁BM were found to be (19.3, 4.8, 6.3) and (20.2, 5.4, 4.5) MPa{sup 1/2}, respectively, with an error of ± 0.8 MPa{sup 1/2}. Based on the solubility properties of the two materials, three new solvents (thiophene, trichloroethylene and carbon disulfide) were utilized for the DPP(TBFu)₂:PC₇₁BM system which, after device optimization, led to power conversion efficiencies up to 4.3%.

Neuroprotective effect of selective DPP-4 inhibitor in experimental vascular dementia.

PubMed

Jain, Swati; Sharma, Bhupesh

2015-12-01

Vascular risk factors are associated with a higher incidence of dementia. Diabetes mellitus is considered as a main risk factor for Alzheimer's disease and vascular dementia. Both forms of dementia are posing greater risk to the world population and are increasing at a faster rate. In the past we have reported the induction of vascular dementia by experimental diabetes. This study investigates the role of vildagliptin, a dipeptidyl peptidase-4 inhibitor in the pharmacological interdiction of pancreatectomy diabetes induced vascular endothelial dysfunction and subsequent vascular dementia in rats. Attentional set shifting and Morris water-maze test were used for assessment of learning and memory. Vascular endothelial function, blood brain barrier permeability, serum glucose, serum nitrite/nitrate, oxidative stress (viz. aortic superoxide anion, brain thiobarbituric acid reactive species and brain glutathione), brain calcium and inflammation (myeloperoxidase) were also estimated. Pancreatectomy diabetes rats have shown impairment of endothelial function, blood brain barrier permeability, learning and memory along with increase in brain inflammation, oxidative stress and calcium. Administration of vildagliptin has significantly attenuated pancreatectomy induced impairment of learning, memory, endothelial function, blood brain barrier permeability and biochemical parameters. It may be concluded that vildagliptin, a dipeptidyl peptidase-4 inhibitor may be considered as potential pharmacological agents for the management of pancreatectomy induced endothelial dysfunction and subsequent vascular dementia. The selective modulators of dipeptidyl peptidase-4 may further be explored for their possible benefits in vascular dementia. Copyright © 2015 Elsevier Inc. All rights reserved.

Atopic dermatitis: a review of topical nonsteroid therapy

PubMed Central

Papier, Ariana

2018-01-01

Background Atopic dermatitis is a chronic inflammatory skin condition that affects up to 20% of children and 3% of adults globally. Although topical corticosteroids are considered to be the first-line agents, they can be associated with cutaneous and systemic adverse effects. Since the early 2000s, two new classes of nonsteroid topical therapies, topical calcineurin inhibitors and phosphodiesterase 4 (PDE4) inhibitors, have been introduced and provide a safe treatment alternative. Method We performed a search and review of clinical trials that examined the safety and efficacy of topical calcineurin inhibitors and PDE4 inhibitors. The search was conducted using the PubMed database as well as preselected keywords and filters. This review focuses on the safety and efficacy of each therapy. Results Sixty-nine clinical trials identified in this study have demonstrated the efficacy and safety of topical calcineurin and a single novel PDE4 inhibitor in the treatment of atopic dermatitis. Topical calcineurin inhibitors have been shown to be effective in both achieving lesion clearance as well as reducing relapse when used long-term and proactively. Similarly, in clinical trials the PDE4 inhibitor showed success in lesion clearance and symptom management. All three therapies (pimecrolimus, tacrolimus, crisaborole) are associated with low systemic absorption. No clinical trials to date have shown an increased risk of systemic adverse events or malignancy such as lymphoma. The most commonly reported treatment-related adverse event across all three therapies was application-site discomfort, pain or pruritus. It is important to note that long-term studies are not yet available for the novel PDE4 inhibitor. Discussion Topical calcineurin inhibitors provide a safe and effective alternative to topical corticosteroid use in the treatment of atopic dermatitis. Although the US Food and Drug Administration (FDA) black box warning for topical calcineurin inhibitors remains, studies have not shown an increased risk of malignancy. These warnings have caused a decline in use in favor of topical steroids. A novel PDE4 inhibitor has shown efficacy and safety in studies up to one year. Further long-term safety data is needed. PMID:29632548

Atopic dermatitis: a review of topical nonsteroid therapy.

PubMed

Papier, Ariana; Strowd, Lindsay C

2018-01-01

Atopic dermatitis is a chronic inflammatory skin condition that affects up to 20% of children and 3% of adults globally. Although topical corticosteroids are considered to be the first-line agents, they can be associated with cutaneous and systemic adverse effects. Since the early 2000s, two new classes of nonsteroid topical therapies, topical calcineurin inhibitors and phosphodiesterase 4 (PDE4) inhibitors, have been introduced and provide a safe treatment alternative. We performed a search and review of clinical trials that examined the safety and efficacy of topical calcineurin inhibitors and PDE4 inhibitors. The search was conducted using the PubMed database as well as preselected keywords and filters. This review focuses on the safety and efficacy of each therapy. Sixty-nine clinical trials identified in this study have demonstrated the efficacy and safety of topical calcineurin and a single novel PDE4 inhibitor in the treatment of atopic dermatitis. Topical calcineurin inhibitors have been shown to be effective in both achieving lesion clearance as well as reducing relapse when used long-term and proactively. Similarly, in clinical trials the PDE4 inhibitor showed success in lesion clearance and symptom management. All three therapies (pimecrolimus, tacrolimus, crisaborole) are associated with low systemic absorption. No clinical trials to date have shown an increased risk of systemic adverse events or malignancy such as lymphoma. The most commonly reported treatment-related adverse event across all three therapies was application-site discomfort, pain or pruritus. It is important to note that long-term studies are not yet available for the novel PDE4 inhibitor. Topical calcineurin inhibitors provide a safe and effective alternative to topical corticosteroid use in the treatment of atopic dermatitis. Although the US Food and Drug Administration (FDA) black box warning for topical calcineurin inhibitors remains, studies have not shown an increased risk of malignancy. These warnings have caused a decline in use in favor of topical steroids. A novel PDE4 inhibitor has shown efficacy and safety in studies up to one year. Further long-term safety data is needed.

Integrated analyses of proteins and their glycans in a magnetic bead-based multiplex assay format.

PubMed

Li, Danni; Chiu, Hanching; Chen, Jing; Zhang, Hui; Chan, Daniel W

2013-01-01

Well-annotated clinical samples are valuable resources for biomarker discovery and validation. Multiplex and integrated methods that simultaneously measure multiple analytes and generate integrated information about these analytes from a single measurement are desirable because these methods help conserve precious samples. We developed a magnetic bead-based system for multiplex and integrated glycoprotein quantification by immunoassays and glycan detection by lectin immunosorbent assays (LISAs). Magnetic beads coupled with antibodies were used for capturing proteins of interest. Biotinylated antibodies in combination with streptavidin-labeled phycoerythrin were used for protein quantification. In the LISAs, biotinylated detection antibodies were replaced by biotinylated lectins for glycan detection. Using tissue inhibitor of metallopeptidase 1 (TIMP-1), tissue plasminogen activator, membrane metallo-endopeptidase, and dipeptidyl peptidase-IV (DPP-4) as models, we found that the multiplex integrated system was comparable to single immunoassays in protein quantification and LISAs in glycan detection. The merits of this system were demonstrated when applied to well-annotated prostate cancer tissues for validation of biomarkers in aggressive prostate cancer. Because of the system's multiplex ability, we used only 300 ng of tissue protein for the integrated detection of glycans in these proteins. Fucosylated TIMP-1 and DPP-4 offered improved performance over the proteins in distinguishing aggressive and nonaggressive prostate cancer. The multiplex and integrated system conserves samples and is a useful tool for validation of glycoproteins and their glycoforms as biomarkers. © 2012 American Association for Clinical Chemistry

Regulation of Endogenous (Male) Rodent GLP-1 Secretion and Human Islet Insulin Secretion by Antagonism of Somatostatin Receptor 5.

PubMed

Farb, Thomas B; Adeva, Marta; Beauchamp, Thomas J; Cabrera, Over; Coates, David A; Meredith, Tamika DeShea; Droz, Brian A; Efanov, Alexander; Ficorilli, James V; Gackenheimer, Susan L; Martinez-Grau, Maria A; Molero, Victoriano; Ruano, Gema; Statnick, Michael A; Suter, Todd M; Syed, Samreen K; Toledo, Miguel A; Willard, Francis S; Zhou, Xin; Bokvist, Krister B; Barrett, David G

2017-11-01

Incretin and insulin responses to nutrient loads are suppressed in persons with diabetes, resulting in decreased glycemic control. Agents including sulfonylureas and dipeptidyl peptidase-4 inhibitors (DPP4i) partially reverse these effects and provide therapeutic benefit; however, their modes of action limit efficacy. Because somatostatin (SST) has been shown to suppress insulin and glucagonlike peptide-1 (GLP-1) secretion through the Gi-coupled SST receptor 5 (SSTR5) isoform in vitro, antagonism of SSTR5 may improve glycemic control via intervention in both pathways. Here, we show that a potent and selective SSTR5 antagonist reverses the blunting effects of SST on insulin secretion from isolated human islets, and demonstrate that SSTR5 antagonism affords increased levels of systemic GLP-1 in vivo. Knocking out Sstr5 in mice provided a similar increase in systemic GLP-1 levels, which were not increased further by treatment with the antagonist. Treatment of mice with the SSTR5 antagonist in combination with a DPP4i resulted in increases in systemic GLP-1 levels that were more than additive and resulted in greater glycemic control compared with either agent alone. In isolated human islets, the SSTR5 antagonist completely reversed the inhibitory effect of exogenous SST-14 on insulin secretion. Taken together, these data suggest that SSTR5 antagonism should increase circulating GLP-1 levels and stimulate insulin secretion (directly and via GLP-1) in humans, improving glycemic control in patients with diabetes. Copyright © 2017 Endocrine Society.

Novel Dehalogenase Mechanism for 2,3-Dichloro-1-Propanol Utilization in Pseudomonas putida Strain MC4

PubMed Central

Arif, Muhammad Irfan; Samin, Ghufrana; van Leeuwen, Jan G. E.; Oppentocht, Jantien

2012-01-01

A Pseudomonas putida strain (MC4) that can utilize 2,3-dichloro-1-propanol (DCP) and several aliphatic haloacids and haloalcohols as sole carbon and energy source for growth was isolated from contaminated soil. Degradation of DCP was found to start with oxidation and concomitant dehalogenation catalyzed by a 72-kDa monomeric protein (DppA) that was isolated from cell lysate. The dppA gene was cloned from a cosmid library and appeared to encode a protein equipped with a signal peptide and that possessed high similarity to quinohemoprotein alcohol dehydrogenases (ADHs), particularly ADH IIB and ADH IIG from Pseudomonas putida HK. This novel dehalogenating dehydrogenase has a broad substrate range, encompassing a number of nonhalogenated alcohols and haloalcohols. With DCP, DppA exhibited a kcat of 17 s−1. 1H nuclear magnetic resonance experiments indicated that DCP oxidation by DppA in the presence of 2,6-dichlorophenolindophenol (DCPIP) and potassium ferricyanide [K3Fe(CN)6] yielded 2-chloroacrolein, which was oxidized to 2-chloroacrylic acid. PMID:22752160

Comparison of charges and resource use associated with saxagliptin and sitagliptin.

PubMed

Vaidya, Varun; Adhikari, Keyuri; Sheehan, Jack; Kalsekar, Iftekhar

2016-12-01

Saxagliptin and sitagliptin are two commonly used dipeptidyl peptidase-4 (DPP-4) inhibitors. Little is known about their comparative effectiveness in the real world, particularly their impact on cost and resources use. The objective of this study was to analyze charges and resource use associated with saxagliptin and sitagliptin to understand the impact of these DPP-4 inhibitor treatment options in a real-world setting. This was a retrospective, new-user study approved by the Institutional Review Board at the University of Toledo. Data were collected from a US insurance claims dataset (OptumInsight) for patients newly initiating treatment with saxagliptin or sitagliptin between January 1, 2010 and December 31, 2011. ICD-9 code 250 was used to identify patients with T2D. Overall and diabetes-related medical and pharmacy charges were observed. Inpatient hospitalizations were also compared. Propensity score matching was used to balance the cohorts of patients prescribed saxagliptin and sitagliptin. Appropriate univariate statistical tests were applied to the propensity-matched sample to examine differences in resource utilization outcomes. Statistical significance was evaluated at P < 0.05. After the propensity score matching, each cohort included 7711 patients. Saxagliptin treatment was associated with lower overall charges ($13,292 vs $14,032; P = 0.0023) and overall medical charges ($9,540 vs $10,296; P = 0.0024) during the 6-month follow-up period compared with sitagliptin treatment. No significant differences were observed in the overall pharmacy charges ($3,751 vs $3,753; P = 0.6937) and the diabetes-related charges ($5,141 vs $5,232; P = 0.2957). All-cause and diabetes-related inpatient hospitalization rates were significantly lower with saxagliptin treatment (p = 0.0001 and p = 0.0019, respectively). All-caused inpatient charges were also significantly lower with saxagliptin ($2,917.26 vs $3445.89; P < 0.0001). Compared with patients initiating sitagliptin treatment, patients initiating saxagliptin treatment reported lower overall and medical charges and lower overall and diabetes-related hospitalization rates. These findings may aid payers in managing patients with T2D.

Comparison of vildagliptin and sitagliptin in patients with type 2 diabetes and severe renal impairment: a randomised clinical trial.

PubMed

Kothny, Wolfgang; Lukashevich, Valentina; Foley, James E; Rendell, Marc S; Schweizer, Anja

2015-09-01

There are limited data comparing dipeptidyl peptidase-4 (DPP-4) inhibitors directly. We compared the safety and efficacy of vildagliptin and sitagliptin in patients with type 2 diabetes and severe renal impairment (RI). This study was a parallel-arm, randomised, multicentre, double-blind, 24 week study conducted in 87 centres across Brazil and the USA. Patients with type 2 diabetes, either drug naive or treated with any glucose-lowering agents, who had inadequate glycaemic control (HbA1c 6.5-10.0% [48-86 mmol/mol]) and an estimated GFR <30 ml min(-1) [1.73 m](-2) were randomised (via interactive voice response technology) to vildagliptin 50 mg once daily or sitagliptin 25 mg once daily. These doses are recommended in this patient population and considered maximally effective. Participants, investigators and the sponsor were blinded to group assignment. Efficacy endpoints included change in HbA1c and fasting plasma glucose (FPG) at all visits and the primary safety endpoint was assessment of treatment-emergent adverse events. In total, 148 patients were randomised, 83 to vildagliptin and 65 to sitagliptin. All patients were analysed. After 24 weeks, the adjusted mean change in HbA1c was -0.54% (5.9 mmol/mol) from a baseline of 7.52% (59 mmol/mol) with vildagliptin and -0.56% (6.1 mmol/mol) from a baseline of 7.80% (62 mmol/mol) with sitagliptin (p = 0.874). FPG decreased by 0.47 ± 0.37 mmol/l with vildagliptin and increased by 0.16 ± 0.43 mmol/l with sitagliptin (p = 0.185). Both treatments were well tolerated with overall similar safety profiles. At their recommended doses for severe RI, vildagliptin (50 mg once daily) compared with sitagliptin (25 mg once daily) demonstrated similar efficacy and both drugs were well tolerated. This study provides further support for the use of DPP-4 inhibitors in patients with severe RI. ClinicalTrials.gov NCT00616811 (completed) This study was planned and conducted by Novartis.

Workplace Interventions to Prevent Type 2 Diabetes Mellitus: a Narrative Review

PubMed Central

Fedewa, Allison; Moran, Margaret; O’Brien, Matthew; Ackermann, Ronald; Kullgren, Jeffrey T.

2017-01-01

Purpose of review This study aims to summarize the recent peer-reviewed literature on workplace interventions for prevention of type 2 diabetes mellitus (T2DM), including studies that translate the Diabetes Prevention Program (DPP) curriculum to workplace settings (n = 10) and those that use different intervention approaches to achieve the specific objective of T2DM prevention among employees (n = 3). Recent findings Weight reduction was achieved through workplace interventions to prevent T2DM, though such interventions varied substantially in their effectiveness. The greatest weight loss was reported among intensive lifestyle interventions (i.e., at least 4 months in duration) that implemented the structured DPP curriculum (n = 3). Weight reduction was minimal among less intensive interventions, including those that substantially modified the DPP curriculum (n = 2) and those that used non-DPP intervention approaches to prevent T2DM (n = 3). Most studies (n = 12) reported increased levels of physical activity following the intervention. Summary Implementation of the DPP in workplaces may be an effective strategy to prevent T2DM among employees. PMID:28150162

Is Solute Rotation in an Ionic Liquid Influenced by the Addition of Glucose?

PubMed

Maurya, Rajan; Naithani, Sudhanshu; Bandyopadhyay, Dibyendu; Choudhury, Niharendu; Dutt, G B

2017-12-07

Fluorescence anisotropy measurements and molecular dynamics (MD) simulations have been performed to understand the specific interactions of two structurally similar nondipolar solutes, 2,5-dimethyl-1,4-dioxo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DMDPP) and 1,4-dioxo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DPP), with neat 1-butyl-3-methylimidazolium dicyanamide ([BMIM][N(CN) 2 ]) and also in the presence of glucose. It has been observed that the measured reorientation times of DMDPP in neat [BMIM][N(CN) 2 ] follow the predictions of the Stokes-Einstein-Debye hydrodynamic theory with slip boundary condition. Addition of glucose (0.075 and 0.15 mole fraction) has no bearing on the rotational diffusion of the solute apart from the viscosity related effects. In contrast, the reorientation times of DPP in neat [BMIM][N(CN) 2 ] obey stick boundary condition as the hydrogen bond donating solute experiences specific interactions with the dicyanamide anion. No influence of the additive can be noticed on the rotational diffusion of DPP at 0.075 mole fraction of glucose. However, at 0.15 mole fraction of glucose, the reorientation times of the solute at a given viscosity and temperature decrease by 15-40% compared to those obtained in the neat ionic liquid. MD simulations indicate that each DPP molecule hydrogen bonds with two dicyanamide anions in neat ionic liquid. The simulations also reveal that, at 0.15 mole fraction of glucose, the concentration of anions hydrogen bonded to glucose increases significantly; therefore, the percentage of solute molecules that can form hydrogen bonds with two dicyanamide anions decreases to 84, which leads to faster rotation of DPP.

10-year follow-up of diabetes incidence and weight loss in the Diabetes Prevention Program Outcomes Study.

PubMed

Knowler, William C; Fowler, Sarah E; Hamman, Richard F; Christophi, Costas A; Hoffman, Heather J; Brenneman, Anne T; Brown-Friday, Janet O; Goldberg, Ronald; Venditti, Elizabeth; Nathan, David M

2009-11-14

In the 2.8 years of the Diabetes Prevention Program (DPP) randomised clinical trial, diabetes incidence in high-risk adults was reduced by 58% with intensive lifestyle intervention and by 31% with metformin, compared with placebo. We investigated the persistence of these effects in the long term. All active DPP participants were eligible for continued follow-up. 2766 of 3150 (88%) enrolled for a median additional follow-up of 5.7 years (IQR 5.5-5.8). 910 participants were from the lifestyle, 924 from the metformin, and 932 were from the original placebo groups. On the basis of the benefits from the intensive lifestyle intervention in the DPP, all three groups were offered group-implemented lifestyle intervention. Metformin treatment was continued in the original metformin group (850 mg twice daily as tolerated), with participants unmasked to assignment, and the original lifestyle intervention group was offered additional lifestyle support. The primary outcome was development of diabetes according to American Diabetes Association criteria. Analysis was by intention-to-treat. This study is registered with ClinicalTrials.gov, number NCT00038727. During the 10.0-year (IQR 9.0-10.5) follow-up since randomisation to DPP, the original lifestyle group lost, then partly regained weight. The modest weight loss with metformin was maintained. Diabetes incidence rates during the DPP were 4.8 cases per 100 person-years (95% CI 4.1-5.7) in the intensive lifestyle intervention group, 7.8 (6.8-8.8) in the metformin group, and 11.0 (9.8-12.3) in the placebo group. Diabetes incidence rates in this follow-up study were similar between treatment groups: 5.9 per 100 person-years (5.1-6.8) for lifestyle, 4.9 (4.2-5.7) for metformin, and 5.6 (4.8-6.5) for placebo. Diabetes incidence in the 10 years since DPP randomisation was reduced by 34% (24-42) in the lifestyle group and 18% (7-28) in the metformin group compared with placebo. During follow-up after DPP, incidences in the former placebo and metformin groups fell to equal those in the former lifestyle group, but the cumulative incidence of diabetes remained lowest in the lifestyle group. Prevention or delay of diabetes with lifestyle intervention or metformin can persist for at least 10 years. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

Changes in Antidiabetic Drug Prescription and Glycemic Control Trends in Elderly Patients with Type 2 Diabetes Mellitus from 2005-2013: An Analysis of the National Center Diabetes Database (NCDD-03).

PubMed

Yamamoto-Honda, Ritsuko; Takahashi, Yoshihiko; Mori, Yasumichi; Yamashita, Shigeo; Yoshida, Yoko; Kawazu, Shoji; Iwamoto, Yasuhiko; Kajio, Hiroshi; Yanai, Hidekatsu; Mishima, Shuichi; Handa, Nobuhiro; Shimokawa, Kotaro; Yoshida, Akiko; Watanabe, Hiroki; Ohe, Kazuhiko; Shimbo, Takuro; Noda, Mitsuhiko

2018-05-01

Objective To analyze the changes in the pharmacotherapy and glycemic control trends in elderly patients with type 2 diabetes mellitus (T2DM) in Japan. Methods We extracted the data of 7,590 patients (5,396 men and 2,194 women; median year of birth: 1945) with T2DM registered in the National Center Diabetes Database for the years 2005 to 2013, and conducted age-stratified (<65, 65-74, and ≥75 years of age) analyses. Results The hemoglobin A1c (HbA1c) levels declined from 2005 to 2013, and for those who received antihyperglycemic drug prescription, the HbA1c levels were lower in the older age group than in the younger age group. In the ≥75 age group, dipeptidyl peptidase-4 inhibitors (DPP4i) became the most frequently prescribed drug (49.1%) in 2013, and sulfonylureas remained the second-most frequently prescribed drug (37.8%) with decreased prescribed doses. The prescription ratio of oral drugs associated with a risk of hypoglycemia was higher in patients ≥75 years of age than in those <75 years of age (40.5% and 26.4%, respectively in 2013), although it showed a downward trend. The prescription rates of insulin for patients ≥75 years of age increased during the study period. Conclusion The pharmacotherapy trends for elderly patients with T2DM changed dramatically in Japan with the launch of DPP4i in 2009. Glycemic control in a considerable portion of the ≥75 age group in Japan was maintained at the expense of potential hypoglycemia by the frequent, although cautious, use of sulfonylureas, glinides and insulin.

One-month comparative efficacy of three topical ectoparasiticides against adult brown dog ticks (Rhipicephalus sanguineus sensu lato) on mixed-bred dogs in controlled environment.

PubMed

Varloud, Marie; Fourie, Josephus J

2015-05-01

This study was designed to compare the therapeutic and residual efficacy for 1 month of three topical ectoparasiticides on mixed-bred dogs against the brown dog tick, Rhipicephalus sanguineus. Adult dogs (n = 32, 10.8-18.4 kg BW) were allocated to 4 groups (n = 8) and infested with 50 adult ticks on days -8, -2, 7, 14, 21, and 28. Within each group, dogs were treated topically on day 0 with a control solution (CS), Vectra 3D (DPP), Frontline Plus (FM), or K9 Advantix (IP). Ticks were enumerated on dogs 24 h after treatment and each subsequent tick infestation by in situ thumb count assessment without removal and at 48 h by combing and removal. Acaricidal efficacy was calculated using arithmetic means for all 24 and 48 h tick count assessments. From 42 to 56% of the total, infested ticks were found on dogs 48 h post-challenge in the CS group. Therapeutic efficacy for all treatments ranged from 45.5 to 64.6% after 48 h of infestation. Residual efficacy after FM treatment was consistently lower compared to DPP or IP treatments at the 24 h assessments on days 8, 22, 23, and 29. Residual efficacy measured at this last time point was 94.8% for DPP, 83.1% for IP, and 46.9% for FM. This study demonstrates that permethrin-based formulations (DPP and IP) provided a quicker onset of residual protection against brown dog ticks compared to FM. Although DPP and IP are both permethrin-based formulations, DPP exhibited consistently higher residual acaricidal efficacies and was the only treatment that provided >90% protection for 1 month at 24 h post challenge.

Combination of TS-021 with metformin improves hyperglycemia and synergistically increases pancreatic β-cell mass in a mouse model of type 2 diabetes.

PubMed

Tajima, Atsushi; Hirata, Takashi; Taniguchi, Kazuo; Kondo, Yukiko; Kato, Sota; Saito-Hori, Masako; Ishimoto, Tsuyoshi; Yamamoto, Koji

2011-10-24

The objectives of this study were to elucidate the effects of a potent dipeptidyl peptidase (DPP)-IV inhibitor, TS-021, combined with/without metformin on glycemic control and pathological changes in pancreatic islets in high-fat diet and streptozotocin-induced (HFD-STZ) diabetic mice. The anti-diabetic effects of TS-021 and/or metformin in HFD-STZ mice were examined in both acute and chronic treatment studies. In addition, we performed immunohistochemical analysis after repeated administration of TS-021 and/or metformin to HFD-STZ mice twice a day for 5 weeks. In the acute treatment study, TS-021 and/or metformin significantly improved glucose tolerance and glucagon-like peptide-1 (GLP-1) level, and TS-021 alone or in combination with metformin significantly increased the plasma insulin level after nutrient ingestion. In the chronic treatment study, TS-021 in combination with metformin significantly lowered the glycosylated hemoglobin level, plasma insulin level, and α-cell-to-β-cell area ratio in pancreatic islets. In particular, the combined treatment synergistically increased the insulin-positive area in pancreatic islets from 32.3% in diabetic mice treated with the vehicle to 51.1% (TS-021 alone, 35.3%; metformin alone, 30.6%). The present study demonstrated that the coadministration of TS-021 and metformin synergistically improved the islet morphology by increasing the circulating level of biologically active GLP-1, which is thought to result from two different mechanisms (namely, an increase in GLP-1 secretion and DPP-IV inhibition). These findings strongly support the rationale for combined treatment with DPP-IV inhibitors plus metformin in clinical practice by clearly demonstrating an anti-diabetic effect associated with the remarkable improvement in pancreatic β-cell morphology. Copyright © 2011 Elsevier Inc. All rights reserved.

Postpartum suppression of ovarian activity with a Deslorelin implant enhanced uterine involution in lactating dairy cows.

PubMed

Silvestre, F T; Bartolome, J A; Kamimura, S; Arteche, A C; Pancarci, S M; Trigg, T; Thatcher, W W

2009-01-01

Holstein cows received, subcutaneously a non-degradable implant containing 5mg of the GnRH agonist Deslorelin (DESL) or no implant (CON) at 2+/-1 days postpartum (dpp). All cows were injected with PGF(2alpha) at 9 dpp. Previous pregnant (PPH) and non-pregnant uterine horns (PNPH) were determined by palpation per rectum. In Experiment 1, cows [DESL implant (n=10) and CON (n=9)] were examined by ultrasonography to record ovarian structures (23, 30 and 37 dpp) and uterine horn and cervical diameters (16, 23, 30 and 37 dpp). Uterine tone was scored before ultrasonography. Vaginoscopy was conducted just after ultrasonography examination to assess cervical discharge and color of the external cervical os. Blood samples were collected on a weekly basis for hormonal analyses. In Experiment 2, cows [DESL implant (n=77) and CON (n=70)] were palpated per rectum and vaginoscopy at 30 dpp for scoring of uterine tone, uterine horns, cervical diameter, and discharge. Blood samples were collected only at 9 dpp. In Experiment 1, DESL-implant-treated cows had more Class 1 follicles (P<0.01), less Class 2 (P<0.01) and Class 3 follicles (P<0.01) and no corpus luteum (CL) formation (P<0.01). In CON cows, six of nine animals had visible CL at 25+/-7 dpp. At 9 dpp plasma concentration of E(2), P(4) (P<0.01) and PGFM (P<0.05) were less in the DESL-implant treatment group. Diameter of PPH (P<0.01), PNPH (P<0.01) and cervix (P=0.08) were less in the DESL-implant treatment associated with greater uterine tone (P=0.07). The DESL-implant cows had a greater frequency of clear cervical discharge (P=0.09) and pink cervical os (P=0.06). In Experiment 2, plasma concentrations of PGFM were less at 9 dpp in DESL-implant treatment (P<0.01). Diameters of the PPH (P<0.01) and PNPH (P<0.01) were less and more uterine tone (P<0.01) in the DESL-implant treatment. Diameter of cervix and frequency of a cervical discharge score did not differ between treatments. Treatment with non-degradable Deslorelin (5mg) implant during postpartum: (1) suppressed ovarian follicular development, (2) enhanced physical involution of the uterus and cervix, (3) increased tone of the uterine wall, (4) decreased frequency of purulent cervical discharges, and (5) reduced inflammatory processes of the reproductive tract.

Vildagliptin , a DPP-4 inhibitor for the twice-daily treatment of type 2 diabetes mellitus with or without metformin.

PubMed

Forst, Thomas; Bramlage, Peter

2014-06-01

Dipeptidyl peptidase-4 inhibitors increase circulating levels of glucagon-like peptide 1 (GLP-1) and glucose dependent insulinotropic polypeptide regulating glucose-dependent insulin secretion. In addition, GLP-1 suppresses glucagon secretion, delays gastric emptying and increases satiety. The combination of vildagliptin with the biguanide metformin is of particular interest because of its complementary mode of action, addressing insulin resistance, alpha- and beta cell function in the islet of the pancreas. Because of the abundance of data supporting the use of vildagliptin alone and in combination with metformin, the present paper aims at giving an overview on the current evidence for its use in patients with type 2 diabetes mellitus. The data suggest that vildagliptin offers similar glycemic control compared to sulfonylureas and thiazolidinediones, while having the benefit of being associated with fewer cases of hypoglycemia and less body weight gain. There is increasing evidence that compared with sulfonylureas, vildagliptin has favorable effects on pancreatic alpha- and beta-cell function. Vildagliptin in combination with metformin, improve glycemic control with a favorable safety and tolerability profile, making it an attractive therapeutic option in patients where metformin monotherapy alone is not sufficient.

CONSENSUS STATEMENT BY THE AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY ON THE COMPREHENSIVE TYPE 2 DIABETES MANAGEMENT ALGORITHM - 2017 EXECUTIVE SUMMARY.

PubMed

Garber, Alan J; Abrahamson, Martin J; Barzilay, Joshua I; Blonde, Lawrence; Bloomgarden, Zachary T; Bush, Michael A; Dagogo-Jack, Samuel; DeFronzo, Ralph A; Einhorn, Daniel; Fonseca, Vivian A; Garber, Jeffrey R; Garvey, W Timothy; Grunberger, George; Handelsman, Yehuda; Hirsch, Irl B; Jellinger, Paul S; McGill, Janet B; Mechanick, Jeffrey I; Rosenblit, Paul D; Umpierrez, Guillermo E

2017-02-01

A1C = hemoglobin A1C AACE = American Association of Clinical Endocrinologists ACCORD = Action to Control Cardiovascular Risk in Diabetes ACCORD BP = Action to Control Cardiovascular Risk in Diabetes Blood Pressure ACEI = angiotensin-converting enzyme inhibitor ADVANCE = Action in Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation AGI = alpha-glucosidase inhibitor apo B = apolipoprotein B ASCVD = atherosclerotic cardiovascular disease BAS = bile acid sequestrant BMI = body mass index BP = blood pressure CHD = coronary heart disease CKD = chronic kidney disease CVD = cardiovascular disease DASH = Dietary Approaches to Stop Hypertension DPP-4 = dipeptidyl peptidase 4 eGFR = estimated glomerular filtration rate FDA = Food and Drug Administration GLP-1 = glucagon-like peptide 1 HDL-C = high-density lipoprotein cholesterol IMPROVE-IT = Improved Reduction of Outcomes: Vytorin Efficacy International Trial LDL-C = low-density lipoprotein cholesterol LDL-P = low-density lipoprotein particle Look AHEAD = Look Action for Health in Diabetes NPH = neutral protamine Hagedorn OSA = obstructive sleep apnea SFU = sulfonylurea SGLT-2 = sodium glucose cotransporter-2 SMBG = self-monitoring of blood glucose T2D = type 2 diabetes TZD = thiazolidinedione VADT = Veterans Affairs Diabetes Trial.

Distinct cellular distributions of Kv4 pore-forming and auxiliary subunits in rat dorsal root ganglion neurons.

PubMed

Matsuyoshi, Hiroko; Takimoto, Koichi; Yunoki, Takakazu; Erickson, Vickie L; Tyagi, Pradeep; Hirao, Yoshihiko; Wanaka, Akio; Yoshimura, Naoki

2012-09-17

Dorsal root ganglia contain heterogeneous populations of primary afferent neurons that transmit various sensory stimuli. This functional diversity may be correlated with differential expression of voltage-gated K(+) (Kv) channels. Here, we examine cellular distributions of Kv4 pore-forming and ancillary subunits that are responsible for fast-inactivating A-type K(+) current. Expression pattern of Kv α-subunit, β-subunit and auxiliary subunit was investigated using immunohistochemistry, in situ hybridization and RT-PCR technique. The two pore-forming subunits Kv4.1 and Kv4.3 show distinct cellular distributions: Kv4.3 is predominantly in small-sized C-fiber neurons, whereas Kv4.1 is seen in DRG neurons in various sizes. Furthermore, the two classes of Kv4 channel auxiliary subunits are also distributed in different-sized cells. KChIP3 is the only significantly expressed Ca(2+)-binding cytosolic ancillary subunit in DRGs and present in medium to large-sized neurons. The membrane-spanning auxiliary subunit DPP6 is seen in a large number of DRG neurons in various sizes, whereas DPP10 is restricted in small-sized neurons. Distinct combinations of Kv4 pore-forming and auxiliary subunits may constitute A-type channels in DRG neurons with different physiological roles. Kv4.1 subunit, in combination with KChIP3 and/or DPP6, form A-type K(+) channels in medium to large-sized A-fiber DRG neurons. In contrast, Kv4.3 and DPP10 may contribute to A-type K(+) current in non-peptidergic, C-fiber somatic afferent neurons. Copyright © 2012 Elsevier Inc. All rights reserved.

Formation of the long range Dpp morphogen gradient.

PubMed

Schwank, Gerald; Dalessi, Sascha; Yang, Schu-Fee; Yagi, Ryohei; de Lachapelle, Aitana Morton; Affolter, Markus; Bergmann, Sven; Basler, Konrad

2011-07-01

The TGF-β homolog Decapentaplegic (Dpp) acts as a secreted morphogen in the Drosophila wing disc, and spreads through the target tissue in order to form a long range concentration gradient. Despite extensive studies, the mechanism by which the Dpp gradient is formed remains controversial. Two opposing mechanisms have been proposed: receptor-mediated transcytosis (RMT) and restricted extracellular diffusion (RED). In these scenarios the receptor for Dpp plays different roles. In the RMT model it is essential for endocytosis, re-secretion, and thus transport of Dpp, whereas in the RED model it merely modulates Dpp distribution by binding it at the cell surface for internalization and subsequent degradation. Here we analyzed the effect of receptor mutant clones on the Dpp profile in quantitative mathematical models representing transport by either RMT or RED. We then, using novel genetic tools, experimentally monitored the actual Dpp gradient in wing discs containing receptor gain-of-function and loss-of-function clones. Gain-of-function clones reveal that Dpp binds in vivo strongly to the type I receptor Thick veins, but not to the type II receptor Punt. Importantly, results with the loss-of-function clones then refute the RMT model for Dpp gradient formation, while supporting the RED model in which the majority of Dpp is not bound to Thick veins. Together our results show that receptor-mediated transcytosis cannot account for Dpp gradient formation, and support restricted extracellular diffusion as the main mechanism for Dpp dispersal. The properties of this mechanism, in which only a minority of Dpp is receptor-bound, may facilitate long-range distribution.

Behavioral Lifestyle Intervention in the Treatment of Obesity

PubMed Central

Looney, Shannon M.; Raynor, Hollie A.

2013-01-01

This article provides an overview of research regarding adult behavioral lifestyle intervention for obesity treatment. We first describe two trials using a behavioral lifestyle intervention to induce weight loss in adults, the Diabetes Prevention Program (DPP) and the Look AHEAD (Action for Health in Diabetes) trial. We then review the three main components of a behavioral lifestyle intervention program: behavior therapy, an energy- and fat-restricted diet, and a moderate- to vigorous-intensity physical activity prescription. Research regarding the influence of dietary prescriptions focusing on macronutrient composition, meal replacements, and more novel dietary approaches (such as reducing dietary variety and energy density) on weight loss is examined. Methods to assist with meeting physical activity goals, such as shortening exercise bouts, using a pedometer, and having access to exercise equipment within the home, are reviewed. To assist with improving weight loss outcomes, broadening activity goals to include resistance training and a reduction in sedentary behavior are considered. To increase the accessibility of behavioral lifestyle interventions to treat obesity in the broader population, translation of efficacious interventions such as the DPP, must be undertaken. Translational studies have successfully altered the DPP to reduce treatment intensity and/or used alternative modalities to implement the DPP in primary care, worksite, and church settings; several examples are provided. The use of new methodologies or technologies that provide individualized treatment and real-time feedback, and which may further enhance weight loss in behavioral lifestyle interventions, is also discussed. PMID:25114557

JAK/STAT controls organ size and fate specification by regulating morphogen production and signalling

PubMed Central

Recasens-Alvarez, Carles; Ferreira, Ana; Milán, Marco

2017-01-01

A stable pool of morphogen-producing cells is critical for the development of any organ or tissue. Here we present evidence that JAK/STAT signalling in the Drosophila wing promotes the cycling and survival of Hedgehog-producing cells, thereby allowing the stable localization of the nearby BMP/Dpp-organizing centre in the developing wing appendage. We identify the inhibitor of apoptosis dIAP1 and Cyclin A as two critical genes regulated by JAK/STAT and contributing to the growth of the Hedgehog-expressing cell population. We also unravel an early role of JAK/STAT in guaranteeing Wingless-mediated appendage specification, and a later one in restricting the Dpp-organizing activity to the appendage itself. These results unveil a fundamental role of the conserved JAK/STAT pathway in limb specification and growth by regulating morphogen production and signalling, and a function of pro-survival cues and mitogenic signals in the regulation of the pool of morphogen-producing cells in a developing organ. PMID:28045022

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park Y. S.; Kale, T.; Wu, Q.

A series of diketopyrrolopyrrole(DPP)-based small molecules have been synthesized by palladium-catalyzed coupling reactions. Electron-donating moieties (benzothiophene, benzoselenophene, and benzotellurophene) are bridged by an electron-withdrawing DPP unit to generate donor-acceptor-donor (D-A-D) type molecules. We observe red-shifts in absorption spectra of these compounds by varying heteroatoms from sulfur to tellurium. In bulk heterojunction solar cells with [6,6]phenyl-C61-butyric acid methyl ester (PC61BM) as acceptor, we obtain power conversion efficiencies of 2.4% (benzothiophene), 4.1% (benzoselenophene), and 3.0% (benzotellurophene), respectively.

Usefulness of a Novel Mobile Diabetes Prevention Program Delivery Platform With Human Coaching: 65-Week Observational Follow-Up

PubMed Central

Michaelides, Andreas; Major, Jennifer; Pienkosz Jr, Edmund; Wood, Meghan; Kim, Youngin

2018-01-01

Background It is widely recognized that the prevalence of obesity and comorbidities including prediabetes and type 2 diabetes continue to increase worldwide. Results from a 24-week Diabetes Prevention Program (DPP) fully mobile pilot intervention were previously published showing promising evidence of the usefulness of DPP-based eHealth interventions on weight loss. Objective This pilot study extends previous findings to evaluate weight loss results of core (up to week 16) and maintenance (postcore weeks) DPP interventions at 65 weeks from baseline. Methods Originally, 140 participants were invited and 43 overweight or obese adult participants with a diagnosis of prediabetes signed up to receive a 24-week virtual DPP with human coaching through a mobile platform. At 65 weeks, this pilot study evaluates weight loss and engagement in maintenance participants by means of repeated measures analysis of variances and backward multiple linear regression to examine predictors of weight loss. Last observation carried forward was used for endpoint measurements. Results At 65 weeks, mean weight loss was 6.15% in starters who read 1 or more lessons per week on 4 or more core weeks, 7.36% in completers who read 9 or more lessons per week on core weeks, and 8.98% in maintenance completers who did any action in postcore weeks (all P<.001). Participants were highly engaged, with 80% (47/59) of the sample completing 9 lessons or more and 69% (32/47) of those completing the maintenance phase. In-app actions related to self-monitoring significantly predicted weight loss. Conclusions In comparison to eHealth programs, this pilot study shows that a fully mobile DPP can produce transformative weight loss. A fully mobile DPP intervention resulted in significant weight loss and high engagement during the maintenance phase, providing evidence for long-term potential as an alternative to in-person DPP by removing many of the barriers associated with in-person and other forms of virtual DPP. PMID:29724709

Solar H2 evolution in water with modified diketopyrrolopyrrole dyes immobilised on molecular Co and Ni catalyst-TiO2 hybrids.

PubMed

Warnan, Julien; Willkomm, Janina; Ng, Jamues N; Godin, Robert; Prantl, Sebastian; Durrant, James R; Reisner, Erwin

2017-04-01

A series of diketopyrrolopyrrole (DPP) dyes with a terminal phosphonic acid group for attachment to metal oxide surfaces were synthesised and the effect of side chain modification on their properties investigated. The organic photosensitisers feature strong visible light absorption ( λ = 400 to 575 nm) and electrochemical and fluorescence studies revealed that the excited state of all dyes provides sufficient driving force for electron injection into the TiO 2 conduction band. The performance of the DPP chromophores attached to TiO 2 nanoparticles for photocatalytic H 2 evolution with co-immobilised molecular Co and Ni catalysts was subsequently studied, resulting in solar fuel generation with a dye-sensitised semiconductor nanoparticle system suspended in water without precious metal components. The performance of the DPP dyes in photocatalysis did not only depend on electronic parameters, but also on properties of the side chain such as polarity, steric hinderance and hydrophobicity as well as the specific experimental conditions and the nature of the sacrificial electron donor. In an aqueous pH 4.5 ascorbic acid solution with a phosphonated DuBois-type Ni catalyst, a DPP-based turnover number (TON DPP ) of up to 205 was obtained during UV-free simulated solar light irradiation (100 mW cm -2 , AM 1.5G, λ > 420 nm) after 1 day. DPP-sensitised TiO 2 nanoparticles were also successfully used in combination with a hydrogenase or platinum instead of the synthetic H 2 evolution catalysts and the platinum-based system achieved a TON DPP of up to 2660, which significantly outperforms an analogous system using a phosphonated Ru tris(bipyridine) dye (TON Ru = 431). Finally, transient absorption spectroscopy was performed to study interfacial recombination and dye regeneration kinetics revealing that the different performances of the DPP dyes are most likely dictated by the different regeneration efficiencies of the oxidised chromophores.

Lowered serum dipeptidyl peptidase IV activity is associated with depressive symptoms and cytokine production in cancer patients receiving interleukin-2-based immunotherapy.

PubMed

Maes, M; Capuron, L; Ravaud, A; Gualde, N; Bosmans, E; Egyed, B; Dantzer, R; Neveu, P J

2001-02-01

There is some evidence that treatment with interleukin-2 (IL-2) and interferon-alpha (IFNalpha) frequently induces depressive symptoms and activation of the inflammatory response system (IRS). There is evidence that major depression is accompanied by lowered serum activity of dipeptidyl peptidase IV (DPP IV; EC 3.4.14.5), a membrane-bound serine protease which catalyses the cleavage of some cytokines and neuro-active peptides and which modulates T cell activation and the production of cytokines, such as IL-2. This study was carried out to examine the effects of immunochemotherapy with IL-2 and IFNalpha, alone and together, in cancer patients on serum DPP IV activity in relation to changes in depressive symptoms and the IRS. The Montgomery and Asberg Rating Scale (MADRS), serum DPP IV activity, and the serum IL-6, and IL-2 receptor (IL-2R) concentrations were measured in 26 patients with metastatic cancers before and three and five days after treatment with IL-2 and IFNalpha, alone or together. Treatment with IL-2 with or without IFNalpha significantly suppressed serum DPP IV activity. The MADRS scores were significantly elevated by treatment with IL-2 with or without IFNalpha, but not IFNalpha alone. The immunochemotherapy-induced decreases in serum DPP IV were significantly and inversely correlated with the increases in the MADRS. Treatment with IL-2 alone or combined with IFNalpha also elevated serum IL-6 and IL-2R. There were significant and inverse correlations between the immuchemotherapy-induced decreases in serum DPP IV and the elevations in serum IL-6 or IL-2R. In conclusion, treatment with IL-2/IFNalpha decreases serum DPP IV activity within 3-5 days and the immunochemotherapy-induced decreases in serum DPP IV activity are significantly and inversely related to treatment-induced increases in severity of depression and signs of activation of the IRS.

A Blue Diketopyrrolopyrrole Sensitizer with High Efficiency in Nickel-Oxide-based Dye-Sensitized Solar Cells.

PubMed

Farré, Yoann; Raissi, Mahfoudh; Fihey, Arnaud; Pellegrin, Yann; Blart, Errol; Jacquemin, Denis; Odobel, Fabrice

2017-06-22

We prepared a series of four new diketopyrrolopyrroles (DPPs)-based sensitizers that exhibit high-molar extinction coefficients, extended absorption into the long wavelengths, and well-suited photoredox properties to act as sensitizers in p-type dye-sensitized solar cells (p-DSSCs). These new DPP dyes, composed of a thienyl DPP core, are substituted on one end either by a thiophene carboxylic (Th) or a 4,4'-[(phenyl)aza]dibenzoic acid as anchoring group and, on the other extremity, either by a proton or a naphthalene diimide (NDI) moiety. These new dyes were completely characterized by absorption and emission spectroscopy along with electrochemistry and they were modeled by time-dependent DFT (TD-DFT) quantum chemical calculations. The photovoltaic study in p-DSSC with iodine-based electrolyte reveals that the Th-DPP-NDI dye is particularly efficient (J sc =7.38 mA cm -2 ; V oc =147 mV; FF=0.32; η=0.35 %) and quite active in the low-energy region of the solar spectrum (above 700 nm), where only a few NiO dyes are effective. To illustrate the potential of DPP dyes in photocathodes, we designed a highly efficient tandem DSSC composed of a TiO 2 photoanode sensitized by the dye D35 and a NiO photocathode sensitized by Th-DPP-NDI. This tandem DSSC gives the highest performances ever reported (J sc =6.73 mA cm -2 ; V oc =910 mV; η=4.1 %) and, importantly, the tandem cell outcompetes with the sub-cells. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Ru(dpp)(3)][(4-Clph)(4)B](2) nanoislands directly assembled on an ITO electrode surface and its electrogenerated chemiluminescence.

PubMed

Chen, Ying; Mao, Jianfei; Liu, Chunhua; Yuan, Hongyan; Xiao, Dan; Choi, Martin M F

2009-01-20

In this work, solid-state tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) ditetrakis(4-chlorophenyl)borate ([Ru(dpp)(3)][(4-Clph)(4)B](2)) nanoislands are assembled spontaneously and simultaneously on an indium-doped tin oxide (ITO) glass electrode surface via a facile dewetting procedure. The fabrication process is very simple and also amenable to mass production. The as-prepared ruthenium complex nanoislands exhibit useful properties. The electrode is more electrochemically active and can produce strong, stable, reproducible solid-state electrochemiluminescence (ECL) signals using oxalate as the coreactant. The self-assembled nanoislands exhibit semiconductor-like broad, red-shift ECL spectrum. More importantly, they extend the application of the ruthenium complex ECL system from the usual alkaline to acidic conditions. The pH turn-off behavior of the ECL is observed for the first time and can serve as an ultrasensitive pH sensor around physiological pH 7.0. The solid-state [Ru(dpp)(3)][(4-Clph)(4)B](2) ECL signal is efficiently inhibited by phenol even at a very low concentration (i.e., 20 nM), thus providing the potential for the determination of phenolic compounds in practical applications.

Saxagliptin Prevents Increased Coronary Vascular Stiffness in Aortic-Banded Mini Swine.

PubMed

Fleenor, Bradley S; Ouyang, An; Olver, T Dylan; Hiemstra, Jessica A; Cobb, Melissa S; Minervini, Gianmaria; Emter, Craig A

2018-06-11

Increased peripheral conduit artery stiffness has been shown in patients with heart failure (HF) with preserved ejection fraction. However, it is unknown whether this phenomenon extends to the coronary vasculature. HF with preserved ejection fraction may be driven, in part, by coronary inflammation, and inhibition of the enzyme DPP-4 (dipeptidyl-peptidase 4) reduces inflammation and oxidative stress. The purpose of this study was to determine the effect of saxagliptin-a DPP-4 inhibitor-on coronary stiffness in aortic-banded mini swine. We hypothesized saxagliptin would prevent increased coronary artery stiffness in a translational swine model with cardiac features of HF with preserved ejection fraction by inhibiting perivascular adipose tissue inflammation. Yucatan mini swine were divided into 3 groups: control, aortic-banded untreated HF, and aortic-banded saxagliptin-treated HF. Ex vivo mechanical testing was performed on the left circumflex and right coronary arteries, and advanced glycation end product, NF-κB (nuclear factor-κB), and nitrotyrosine levels were measured. An increase in the coronary elastic modulus of HF animals was associated with increased vascular advanced glycation end products, NF-κB, and nitrotyrosine levels compared with control and prevented by saxagliptin treatment. Aortas from healthy mice were treated with media from swine perivascular adipose tissue culture to assess its role on vascular stiffening. Conditioned media from HF and saxagliptin-treated HF animals increased mouse aortic stiffness; however, only perivascular adipose tissue from the HF group showed increased advanced glycation end products and NF-κB levels. In conclusion, our data show increased coronary conduit vascular stiffness was prevented by saxagliptin and associated with decreased advanced glycation end products, NF-κB, and nitrotyrosine levels in a swine model with potential relevance to HF with preserved ejection fraction. © 2018 American Heart Association, Inc.

Phosphodiesterase 4 inhibitor and phosphodiesterase 5 inhibitor combination therapy has antifibrotic and anti-inflammatory effects in mdx mice with Duchenne muscular dystrophy.

PubMed

Nio, Yasunori; Tanaka, Masayuki; Hirozane, Yoshihiko; Muraki, Yo; Okawara, Mitsugi; Hazama, Masatoshi; Matsuo, Takanori

2017-12-01

Duchenne muscular dystrophy (DMD) is the most common inherited muscular dystrophy. Patients experience DMD in their 20s from cardiac or respiratory failure related to progressive muscle wasting. Currently, the only treatments for the symptoms of DMD are available. Muscle fibrosis, a DMD feature, leads to reduced muscle function and muscle mass, and hampers pharmaceutical therapeutic efficacy. Although antifibrotic agents may be useful, none is currently approved. Phosphodiesterase 4 (PDE4) inhibitors have exhibited antifibrotic effects in human and animal models. In this study, we showed beneficial effects of the PDE4 inhibitor piclamilast in the DMD mdx mouse. Piclamilast reduced the mRNA level of profibrotic genes, including collagen 1A1, in the gastrocnemius and diaphragm, in the mdx mouse, and significantly reduced the Sirius red staining area. The PDE5 inhibitors sildenafil and tadalafil ameliorated functional muscle ischemia in boys with DMD, and sildenafil reversed cardiac dysfunction in the mdx mouse. Single-treatment piclamilast or sildenafil showed similar antifibrotic effects on the gastrocnemius; combination therapy showed a potent antifibrotic effect, and piclamilast and combination therapy increased peroxisome proliferator-activated receptor γ coactivator-1α mRNA in mouse gastrocnemius. In summary, we confirmed that piclamilast has significant antifibrotic effects in mdx mouse muscle and is a potential treatment for muscle fibrosis in DMD.-Nio, Y., Tanaka, M., Hirozane, Y., Muraki, Y., Okawara, M., Hazama, M., Matsuo, T. Phosphodiesterase 4 inhibitor and phosphodiesterase 5 inhibitor combination therapy has antifibrotic and anti-inflammatory effects in mdx mice with Duchenne muscular dystrophy. © FASEB.

Sarcoidosis Following Anti-PD-1 and Anti-CTLA-4 Therapy for Metastatic Melanoma.

PubMed

Reddy, Swathi B; Possick, Jennifer D; Kluger, Harriet M; Galan, Anjela; Han, Dale

2017-10-01

Immune checkpoint inhibitors represent the newest treatment for stage IV melanoma. These agents are generally well tolerated, however severe immune-related adverse effects have been noted in a small, but clinically significant percentage of patients. Specifically, sarcoidosis is a known potential complication following anti-CTLA-4 therapy. We present 2 cases of pulmonary and cutaneous sarcoidosis developing in patients with stage IV melanoma. Both patients were treated with ipilimumab and anti-PD-1 therapy, and both experienced good oncologic responses to treatment; neither had evidence of preexisting sarcoidosis. Of note, both patients developed sarcoidosis only after undergoing immune checkpoint inhibitor therapy. In 1 patient, sarcoidosis developed after initiation of anti-PD-1 therapy, 3 months after the last dose of anti-CTLA-4 monotherapy, suggesting a synergistic immune dysmodulating effect of both checkpoint inhibitors. Ultimately, both patients' symptoms and radiologic findings resolved with corticosteroid treatment, and both patients have tolerated retreatment with PD-1 inhibitors. Sarcoidosis is a rare complication of immune checkpoint inhibitors and can manifest with severe pulmonary manifestations. However, sarcoidosis in this setting is responsive to corticosteroids and does not necessarily recur with retreatment. It is yet unclear whether the development of sarcoidosis in these patients represents unmasking of preexisting autoimmune tendencies or is a marker of oncologic response.

Effect of Palm Pollen on Sperm Parameters of Infertile Man.

PubMed

Rasekh, Athar; Jashni, Hojjatollah Karimi; Rahmanian, Karamatollah; Jahromi, Abdolreza Sotoodeh

2015-04-01

There is a rapidly growing trend in the consumption of herbal remedies in the developing countries. The aim of this study was to determine the effects of orally administered Date Palm Pollen (DPP) on the results of semen analysis in adult infertile men. Forty infertile men participated in our study. They were treated by Pollen powder 120 mg kg(-1) in gelatinous capsules every other day, for two months. Before and at the end of therapy, the semen was collected after masturbation and sperm numbers, motility and morphology were determined. Our findings revealed that consumption of DPP improved the sperm count. The treatment was significantly increased sperm motility, morphology and forward progressive motility. Date palm pollen seems to cure male infertility by improving the quality of sperm parameters.

Inhibition of dipeptidyl peptidase-4 augments insulin secretion in response to exogenously administered glucagon-like peptide-1, glucose-dependent insulinotropic polypeptide, pituitary adenylate cyclase-activating polypeptide, and gastrin-releasing peptide in mice.

PubMed

Ahrén, Bo; Hughes, Thomas E

2005-04-01

Inhibition of dipeptidyl peptidase-4 (DPP-4) is currently being explored as a new approach to the treatment of type 2 diabetes. This concept has emerged from the powerful and rapid action of the enzyme to inactivate glucagon-like peptide-1 (GLP-1). However, other bioactive peptides with potential influence of islet function are also substrates of DPP-4. Whether this inactivation may add to the beneficial effects of DPP-4 inhibition is not known. In this study, we explored whether DPP-4 inhibition by valine-pyrrolidide (val-pyr; 100 micromol/kg administered through gastric gavage at t = -30 min) affects the insulin and glucose responses to iv glucose (1 g/kg) together with GLP-1 (10 nmol/kg), glucose-dependent insulinotropic polypeptide (GIP; 10 nmol/kg), pituitary adenylate cyclase-activating polypeptide 38 (PACAP38; 1.3 nmol/kg), or gastrin-releasing peptide (GRP; 20 nmol/kg) given at t = 0 in anesthetized C57BL/6J mice. It was found that the acute (1-5 min) insulin response to GLP-1 was augmented by val-pyr by 80% (4.2 +/- 0.4 vs. 7.6 +/- 0.8 nmol/liter), that to GIP by 40% (2.7 +/- 0.3 vs. 3.8 +/- 0.4 nmol/liter), that to PACAP38 by 75% (4.6 +/- 0.5 vs. 8.1 +/- 0.6 nmol/liter), and that to GRP by 25% (1.8 +/- 0.2 vs. 2.3 +/- 0.3 nmol/liter; all P < 0.05 or less). This was associated with enhanced glucose elimination rate after GLP-1 [glucose elimination constant (K(G)) 2.1 +/- 0.2 vs. 3.1 +/- 0.3%/min] and PACAP38 (2.1 +/- 0.3 vs. 3.2 +/- 0.3%/min; both P < 0.01), but not after GIP or GRP. The augmented insulin response to GRP by val-pyr was prevented by the GLP-1 receptor antagonist, exendin(3) (9-39), raising the possibility that GRP effects may occur secondary to stimulation of GLP-1 secretion. We conclude that DPP-4 inhibition augments the insulin response not only to GLP-1 but also to GIP, PACAP38, and GRP.

Phenolic Compounds from Fermented Berry Beverages Modulated Gene and Protein Expression To Increase Insulin Secretion from Pancreatic β-Cells in Vitro.

PubMed

Johnson, Michelle H; de Mejia, Elvira Gonzalez

2016-03-30

Berries are a rich source of bioactive phenolic compounds that are able to bind and inhibit the enzyme dipeptidyl peptidase-IV (DPP-IV), a current target for type-2 diabetes therapy. The objectives were to determine the role of berry phenolic compounds to modulate incretin-cleaving DPP-IV and its substrate glucagon-like peptide-1 (GLP-1), insulin secretion from pancreatic β-cells, and genes and proteins involved in the insulin secretion pathway using cell culture. Anthocyanins (ANC) from 50% blueberry-50% blackberry (Blu-Bla) and 100% blackberry (Bla) fermented beverages at 50 μM cyanidin-3-glucoside equivalents increased (p < 0.05) glucose-stimulated insulin secretion from pancreatic β-cells (iNS-1E) both when applied directly and following simulated absorption through Caco-2 cells (by 233 and 100 μIU insulin/mL, respectively). ANC 50%Blu-Bla and ANC 100%Bla upregulated the gene for incretin hormone GLP-1 (fold-change 3.0 ± 1.4 and 2.0 ± 0.3, respectively) and genes in the insulin secretory pathway including insulin-like growth factor 1 receptor (iGF1R, 2.3 ± 0.6 and 1.6 ± 0.3, respectively), and increased (p < 0.05) the protein expression of insulin-like growth factor 2 (IGF-II), insulin-like growth factor binding proteins (IGFBP-2 and 3), and vascular endothelial growth factor (VEGF) in iNS-1E cells. Taken together, anthocyanins, predominantly delphinidin-3-arabinoside, from fermented berry beverages have the potential to modulate DPP-IV and its substrate GLP-1, to increase insulin secretion, and to upregulate expression of mRNA of insulin-receptor associated genes and proteins in pancreatic β-cells.

Evaluation of optical excitation conditions for ruthenium complex for biosensor optodes

NASA Astrophysics Data System (ADS)

Pieper, Sean; Zhong, Zhong; Lear, Kevin L.; Reardon, Ken

2007-03-01

Development of a fiber optic biosensor incorporating genetically engineered enzymes which catalyze chlorinated ethenes in an oxygen-consuming reaction for in situ monitoring of groundwater contaminants motivates optimization of optode excitation conditions. These conditions affect the sensitivity, signal-to-noise, and optode service life impacting the quality of the overall biosensor. Optodes are generally comprised of a fluorophore conjugated with a polymer as a substrate cross linked at the distal end of a fiber optic. We investigate the excitation conditions of tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) chloride (Ru(dpp)3) conjugated with poly(vinyl alcohol) (PVOH) as an optode. A reported advantage of Ru(dpp)3 is that it has no emission spectral shift occurring under varying chemical and environmental conditions. Photostability degradation due to photobleaching of Ru(dpp)3 with PVOH as a substrate is explored by varying the optical irradiance of the fluorophore containing optode. Other issues relating to practical implementation of Ru(dpp)3 as oxygen sensitive biosensors will be discussed.

Treatment of type 2 diabetes with saxagliptin: a pharmacoeconomic evaluation in Argentina.

PubMed

Elgart, Jorge F; Caporale, Joaquin E; Gonzalez, Lorena; Aiello, Eleonora; Waschbusch, Maximiliano; Gagliardino, Juan J

2013-04-27

The increasing prevalence of diabetes and its inadequate management results in a heavy burden of the disease for the patients, the health and the productive system and the overall community. Consequently, it is necessary to have new effective drugs to treat people with diabetes to decrease such burden. DPP-4 inhibitors can help to cope with this demand, but its usage is challenged by its apparent high cost. The aim of the current study was to compare a simulated cost-effectiveness ratio of metformin (MET) plus one drug of the DPP-4 inhibitors family, saxagliptin (SAXA) or sulfonylurea (SU) treatment during a 20-year period, from the perspective of the social security system, in a cohort of people with Type 2 diabetes (T2DM) who did not attain glycosylated hemoglobin treatment target values only with MET. A discrete event simulation model (Cardiff diabetes model) based on UKPDS 68 was used to simulate disease progression and to estimate the economic and health treatment consequences in people with T2DM. The clinical efficacy parameters for SAXA administration were obtained from the literature; local standard costs were considered for drug acquisition, adverse events (AEs), and micro/macrovascular complications. Costs were expressed in US dollars (2009) with an annual 3.5% discount and a 20-year time horizon. The SAXA + MET treated group had a lower number of non-fatal events than the SU + MET treated group. The model also predicted a lower number of fatal macrovascular events for the SAXA + MET group (149.6 vs. 152.8). The total cost of the SAXA + MET cohort was 15% higher than that of the SU + MET cohort. Treatment with SAXA + MET resulted in a higher number of quality-adjusted life years (QALYs) (9.54 vs. 9.32) and life-years gained (LYGs) (20.84 vs. 20.76) compared to those treated with SU + MET. The incremental cost per QALY and LYG gained was $7,374 and $20,490, respectively. According to the criteria proposed by the Commission on Macroeconomics and Health, the use of the combination SAXA + MET is highly cost-effective in Argentina.

Treatment of type 2 diabetes with saxagliptin: a pharmacoeconomic evaluation in Argentina

PubMed Central

2013-01-01

Background The increasing prevalence of diabetes and its inadequate management results in a heavy burden of the disease for the patients, the health and the productive system and the overall community. Consequently, it is necessary to have new effective drugs to treat people with diabetes to decrease such burden. DPP-4 inhibitors can help to cope with this demand, but its usage is challenged by its apparent high cost. The aim of the current study was to compare a simulated cost-effectiveness ratio of metformin (MET) plus one drug of the DPP-4 inhibitors family, saxagliptin (SAXA) or sulfonylurea (SU) treatment during a 20-year period, from the perspective of the social security system, in a cohort of people with Type 2 diabetes (T2DM) who did not attain glycosylated hemoglobin treatment target values only with MET. Methods A discrete event simulation model (Cardiff diabetes model) based on UKPDS 68 was used to simulate disease progression and to estimate the economic and health treatment consequences in people with T2DM. The clinical efficacy parameters for SAXA administration were obtained from the literature; local standard costs were considered for drug acquisition, adverse events (AEs), and micro/macrovascular complications. Costs were expressed in US dollars (2009) with an annual 3.5% discount and a 20-year time horizon. Results The SAXA + MET treated group had a lower number of non-fatal events than the SU + MET treated group. The model also predicted a lower number of fatal macrovascular events for the SAXA + MET group (149.6 vs. 152.8). The total cost of the SAXA + MET cohort was 15% higher than that of the SU + MET cohort. Treatment with SAXA + MET resulted in a higher number of quality-adjusted life years (QALYs) (9.54 vs. 9.32) and life-years gained (LYGs) (20.84 vs. 20.76) compared to those treated with SU + MET. The incremental cost per QALY and LYG gained was $7,374 and $20,490, respectively. Conclusions According to the criteria proposed by the Commission on Macroeconomics and Health, the use of the combination SAXA + MET is highly cost-effective in Argentina. PMID:23621944

Feasibility of SH2 Binding as a Prognostic and Diagnostic Indicator: Probing the Tyrosine Phosphorylation State in Breast Cancer by Src Homology 2 Domain Binding

DTIC Science & Technology

2005-08-01

osteoclastic bone resorption, respectively. Despite formidable difficulties in drug design due to the lability and poor cell permeability of negatively...with LysO?,D6, generally been treated with two categories of drugs : bone displacing water molecules found in the previous X-ray resorption inhibitors...and Dpp [236-238]. cancer drugs , of which only 12 were shown to have survival Researchers from Aventis reported the superimposition benefit in

Highly active antiretroviral therapy including protease inhibitors does not confer a unique CD4 cell benefit. The AVANTI and INCAS Study Groups.

PubMed

2000-07-07

To determine if triple combination therapy, particularly including HIV protease inhibitors (PI), confers an unique immunological benefit that is independent of reductions of plasma viral load (pVL). The correlation between changes from baseline in CD4 cell count and pVL was examined at all time points up to 52 weeks in three randomized clinical trials (AVANTI-2, AVANTI-3 and INCAS) that compared dual nucleoside therapy with triple combination therapy. Individual pVL and CD4 cell counts changes from baseline were entered into multivariate linear regression models for patients receiving double therapy and for those receiving triple therapy including a PI and/or a non-nucleoside reverse transcriptase inhibitor (NNRTI), and the null hypothesis was tested. After 52 weeks of therapy, the relationship between changes from baseline CD4 cell count and pVL was independent of whether patients were assigned double or triple therapy (P = 0.23 and 0.69 for intercept and slope, respectively), or whether patients were assigned triple therapy including a PI or triple therapy including an NNRTI (P = 0.92 and 0.95, respectively). Less than 5% of patients ever had 'discordant' increases in both CD4 cell count and pVL compared with baseline, and this proportion was unrelated to the class of therapy used. 'Discordant' decreases from baseline in both parameters were observed in up to 35% of individuals. The correlation between pVL and CD4 cell count changes from baseline improved over time on therapy, regardless of the therapeutic regimen involved. The data provide no evidence for a CD4 cell count benefit of highly active antiretroviral therapy (HAART) unique to triple therapy or PI-containing regimens.

Phosphodiesterase 4 Inhibitor Therapies for Atopic Dermatitis: Progress and Outlook.

PubMed

Ahluwalia, Jusleen; Udkoff, Jeremy; Waldman, Andrea; Borok, Jenna; Eichenfield, Lawrence F

2017-09-01

Phosphodiesterase 4 (PDE4) is a cyclic AMP degrading enzyme in leukocytes. Several decades ago, increased PDE activity was demonstrated in patients with atopic dermatitis (AD). Currently, several PDE4 inhibitors in both topical and oral formulation have been developed to target the inflammatory cascade of AD. This review shows the pathogenic rationale behind these inhibitors, and discusses multiple PDE4 inhibitors that are under evaluation or in the market. PDE4 inhibitors may be considered as favorable agents in the repertoire of current interventions for AD.

Glycaemic control and antidiabetic therapy in patients with diabetes mellitus and chronic kidney disease - cross-sectional data from the German Chronic Kidney Disease (GCKD) cohort.

PubMed

Busch, Martin; Nadal, Jennifer; Schmid, Matthias; Paul, Katharina; Titze, Stephanie; Hübner, Silvia; Köttgen, Anna; Schultheiss, Ulla T; Baid-Agrawal, Seema; Lorenzen, Johan; Schlieper, Georg; Sommerer, Claudia; Krane, Vera; Hilge, Robert; Kielstein, Jan T; Kronenberg, Florian; Wanner, Christoph; Eckardt, Kai-Uwe; Wolf, Gunter

2016-06-11

Diabetes mellitus (DM) is the leading cause of end-stage renal disease. Little is known about practice patterns of anti-diabetic therapy in the presence of chronic kidney disease (CKD) and correlates with glycaemic control. We therefore aimed to analyze current antidiabetic treatment and correlates of metabolic control in a large contemporary prospective cohort of patients with diabetes and CKD. The German Chronic Kidney Disease (GCKD) study enrolled 5217 patients aged 18-74 years with an estimated glomerular filtration rate (eGFR) between 30-60 mL/min/1.73 m(2) or proteinuria >0.5 g/d. The use of diet prescription, oral anti-diabetic medication, and insulin was assessed at baseline. HbA1c, measured centrally, was the main outcome measure. At baseline, DM was present in 1842 patients (35 %) and the median HbA1C was 7.0 % (25(th)-75(th) percentile: 6.8-7.9 %), equalling 53 mmol/mol (51, 63); 24.2 % of patients received dietary treatment only, 25.5 % oral antidiabetic drugs but not insulin, 8.4 % oral antidiabetic drugs with insulin, and 41.8 % insulin alone. Metformin was used by 18.8 %. Factors associated with an HbA1C level >7.0 % (53 mmol/mol) were higher BMI (OR = 1.04 per increase of 1 kg/m(2), 95 % CI 1.02-1.06), hemoglobin (OR = 1.11 per increase of 1 g/dL, 95 % CI 1.04-1.18), treatment with insulin alone (OR = 5.63, 95 % CI 4.26-7.45) or in combination with oral antidiabetic agents (OR = 4.23, 95 % CI 2.77-6.46) but not monotherapy with metformin, DPP-4 inhibitors, or glinides. Within the GCKD cohort of patients with CKD stage 3 or overt proteinuria, antidiabetic treatment patterns were highly variable with a remarkably high proportion of more than 50 % receiving insulin-based therapies. Metabolic control was overall satisfactory, but insulin use was associated with higher HbA1C levels.

Three extracellular dipeptidyl peptidases found in Aspergillus oryzae show varying substrate specificities.

PubMed

Maeda, Hiroshi; Sakai, Daisuke; Kobayashi, Takuji; Morita, Hiroto; Okamoto, Ayako; Takeuchi, Michio; Kusumoto, Ken-Ichi; Amano, Hitoshi; Ishida, Hiroki; Yamagata, Youhei

2016-06-01

Three extracellular dipeptidyl peptidase genes, dppB, dppE, and dppF, were unveiled by sequence analysis of the Aspergillus oryzae genome. We investigated their differential enzymatic profiles, in order to gain an understanding of the diversity of these genes. The three dipeptidyl peptidases were expressed using Aspergillus nidulans as the host. Each recombinant enzyme was purified and subsequently characterized. The enzymes displayed similar optimum pH values, but optimum temperatures, pH stabilities, and substrate specificities varied. DppB was identified as a Xaa-Prolyl dipeptidyl peptidase, while DppE scissile substrates were similar to the substrates for Aspergillus fumigatus DPPV (AfDPPV). DppF was found to be a novel enzyme that could digest both substrates for A. fumigatus DPPIV and AfDPPV. Semi-quantitative PCR revealed that the transcription of dppB in A. oryzae was induced by protein substrates and repressed by the addition of an inorganic nitrogen source, despite the presence of protein substrates. The transcription of dppE depended on its growth time, while the transcription of dppF was not affected by the type of the nitrogen source in the medium, and it started during the early stage of the fungal growth. Based on these results, we conclude that these enzymes may represent the nutrition acquisition enzymes. Additionally, DppF may be one of the sensor peptidases responsible for the detection of the protein substrates in A. oryzae environment. DppB may be involved in nitrogen assimilation control, since the transcription of dppB was repressed by NaNO3, despite the presence of protein substrates.

Substrate Binding Protein DppA1 of ABC Transporter DppBCDF Increases Biofilm Formation in Pseudomonas aeruginosa by Inhibiting Pf5 Prophage Lysis

PubMed Central

Lee, Yunho; Song, Sooyeon; Sheng, Lili; Zhu, Lei; Kim, Jun-Seob; Wood, Thomas K.

2018-01-01

Filamentous phage impact biofilm development, stress tolerance, virulence, biofilm dispersal, and colony variants. Previously, we identified 137 Pseudomonas aeruginosa PA14 mutants with more than threefold enhanced and 88 mutants with more than 10-fold reduced biofilm formation by screening 5850 transposon mutants (PLoS Pathogens 5: e1000483, 2009). Here, we characterized the function of one of these 225 mutations, dppA1 (PA14_58350), in regard to biofilm formation. DppA1 is a substrate-binding protein (SBP) involved in peptide utilization via the DppBCDF ABC transporter system. We show that compared to the wild-type strain, inactivating dppA1 led to 68-fold less biofilm formation in a static model and abolished biofilm formation in flow cells. Moreover, the dppA1 mutant had a delay in swarming and produced 20-fold less small-colony variants, and both biofilm formation and swarming were complemented by producing DppA1. A whole-transcriptome analysis showed that only 10 bacteriophage Pf5 genes were significantly induced in the biofilm cells of the dppA1 mutant compared to the wild-type strain, and inactivation of dppA1 resulted in a 600-fold increase in Pf5 excision and a million-fold increase in phage production. As expected, inactivating Pf5 genes PA0720 and PA0723 increased biofilm formation substantially. Inactivation of DppA1 also reduced growth (due to cell lysis). Hence, DppA1 increases biofilm formation by repressing Pf5 prophage. PMID:29416528

The effects of dual-therapy intensification with insulin or dipeptidylpeptidase-4 inhibitor on cardiovascular events and all-cause mortality in patients with type 2 diabetes: A retrospective cohort study.

PubMed

Jil, Mamza; Rajnikant, Mehta; Richard, Donnelly; Iskandar, Idris

2017-07-01

To compare time to a composite endpoint of non-fatal acute myocardial infarction, non-fatal stroke or all-cause mortality in patients with type 2 diabetes mellitus who had their treatment intensified with a dipeptidylpeptidase-4 inhibitor or insulin following dual-therapy (metformin plus sulfonylurea) failure. A retrospective cohort study was conducted on 5238 patients newly treated with either a dipeptidylpeptidase-4 inhibitor or insulin following dual-therapy failure (2007-2014). Data were sourced from UK General Practices. The risk of the composite outcome was compared between two treatment groups: metformin + sulfonylurea + insulin ( n = 1584) and metformin + sulfonylurea + dipeptidylpeptidase-4 inhibitor ( n = 3654), while adjusting for baseline covariates. Follow-up was for up to 5 years. Propensity score matching analysis and Cox proportional hazard models were employed. Overall, 123 and 171 composite outcome events occurred among patients who added insulin versus dipeptidylpeptidase-4 inhibitor, respectively (44.5 vs 14.6 events per 1000 person-years). Addition of insulin was associated with a significantly higher hazard ratio versus the addition of a dipeptidylpeptidase-4 inhibitor (adjusted hazard ratio = 2.6, 95% confidence interval: 1.9-3.4; p < 0.01), an effect that was more pronounced in obese (body mass index: 30-34.9 kg/m 2 ) patients (corresponding adjusted hazard ratio 3.6, 95% confidence interval: 2.3-5.6; p < 0.01). In routine clinical practice, intensification of metformin + sulfonylurea therapy by adding insulin is associated with increased risk of cardiovascular events and death compared with adding a dipeptidylpeptidase-4 inhibitor. These findings are in line with suggestions from previous studies regarding the cardiovascular safety of insulin in type 2 diabetes mellitus, but should be interpreted with caution.

Expression of recombinant human α-lactalbumin in milk of transgenic cloned pigs is sufficient to enhance intestinal growth and weight gain of suckling piglets.

PubMed

Ma, Jin; Li, Qiuyan; Li, Yan; Wen, Xiao; Li, Zhiyuan; Zhang, Zaihu; Zhang, Jiuming; Yu, Zhengquan; Li, Ning

2016-06-10

Human α-lactalbumin (HLA) has very high nutritional value and important physiological functions during the neonatal period. The peptides derived from HLA provide diverse health benefits including antimicrobial, antiviral, immune-modulating, and antihypertensive effects. Thus, it is worth investigating the effects on offspring development of increasing HLA in milk. In this study, we found that recombinant human α-lactalbumin (rHLA) exhibits efficient inhibition of dipeptidyl peptidase-IV (DPP-IV) activity in an in vitro simulated gastrointestinal digestion system. Using a BAC clone containing the complete HLA gene as a candidate vector, we generated two lines of transgenic cloned sows via somatic cell nuclear transfer that over-expressed rHLA. The average concentrations of rHLA in milk from the two lines of transgenic cloned sows were 2.24 ± 0.71 mg/ml and 2.67 ± 1.29 mg/ml. The feeding experiments revealed that rHLA represses dipeptidyl peptidase-IV (DPP-IV) activity in vivo. Furthermore, the piglets reared by rHLA transgenic cloned sows exhibit better performance in gain of body weight and intestine growth than the control piglets reared by non-transgenic sows. Therefore, these findings indicate that rHLA could serve as a natural precursor for a DPP-IV inhibitor, and the transgenic technology that produced the over-expression of rHLA could be a useful method for pig breeders to improve lactation performance. Copyright © 2016. Published by Elsevier B.V.

Peroxidase-catalyzed stabilization of 2,4-dichlorophenol in alkali-extracted soils.

PubMed

Palomo, Mónica; Bhandari, Alok

2011-01-01

Horseradish peroxidase- (HRP) mediated stabilization of phenolic contaminants is a topic of interest due to its potential for remediation of contaminated soils. This study evaluated the sorption of 2,4-dichlorophenol (DCP) and its HRP-mediated stabilization in two alkali-extracted soils. Alkali extraction reduced the soil organic matter (SOM) contents of the geomaterials and enriched the residual SOM with humin C. Sorption of DCP on these sorbents was complete within 1 d. However, most of the sorbed DCP was removed from the geomaterials by water and methanol, suggesting weak solute-sorbent interactions. The addition of HRP resulted in the generation of DCP polymerization products (DPP), which partitioned between the aqueous and solid phases. The DPP phase distribution was rapid and complete within 24 h. Between 70 and 90% of the added DCP was converted to DPP and up to 43% of the initial aqueous phase contaminant was transformed into a residue that was resistant to extraction with methanol. Bound residues of DPP increased with initial aqueous phase solute concentration and remained fairly constant after 7 d of contact. Contaminant stabilization was noted to be high in the humin-mineral geomaterial. Results illustrate that HRP may be effective in stabilizing phenolic contaminants in subsoils that are likely to contain SOM enriched in humin C.

Effect of rifampicin on the pharmacokinetics and pharmacodynamics of saxagliptin, a dipeptidyl peptidase-4 inhibitor, in healthy subjects

PubMed Central

Upreti, Vijay V; Boulton, David W; Li, Li; Ching, Agatha; Su, Hong; LaCreta, Frank P; Patel, Chirag G

2011-01-01

AIM To investigate the effect of co-administration of rifampicin, a potent inducer of cytochrome P450 (CYP) 3A4 enzymes, on the pharmacokinetics (PK) and pharmacodynamics (PD) of saxagliptin and 5-hydroxy saxagliptin in healthy subjects. Saxagliptin is metabolized by CYP3A4/3A5 to 5-hydroxy saxagliptin, its major pharmacologically active metabolite. METHODS In a non-randomized, open label, single sequence design, 14 healthy subjects received single oral doses of saxagliptin 5 mg with and without steady-state rifampicin (600 mg once daily for 6 days). PK (saxagliptin and 5-hydroxy saxagliptin) and PD (plasma DPP-4 activity) were measured for up to 24 h on days 1 and 7. RESULTS Concomitant administration with rifampicin resulted in 53% (point estimate 0.47, 90% CI 0.38, 0.57) and 76% (point estimate 0.24, 90% CI 0.21, 0.27) decreases in the geometric mean Cmax and AUC values of saxagliptin, respectively, with a 39% (point estimate 1.39, 90% CI 1.23, 1.56) increase in the geometric mean Cmax and no change (point estimate 1.03, 90% CI 0.97, 1.09) in the AUC of 5-hydroxy saxagliptin. Similar maximum % inhibition and area under the % inhibition−time effect curve over 24 h for DPP-4 activity were observed when saxagliptin was administered alone or with rifampicin. The saxagliptin total active moieties exposure (AUC) decreased by 27% (point estimate 0.73, 90% CI 0.66, 0.81). Saxagliptin with or without rifampicin in this study was generally well tolerated. CONCLUSIONS Lack of change of PD effect of saxagliptin is consistent with the observed 27% reduction in systemic exposure to the total active moieties, which is not considered clinically meaningful. Based on these findings, it is not necessary to adjust the saxagliptin dose when co-administered with rifampicin. PMID:21651615

Glucagon-like peptide 1 and the cardiovascular system.

PubMed

Fava, Stephen

2014-01-01

Glucagon-like peptide 1 (GLP1) is a major incretin hormone. This means that it is secreted by the gut in response to food and helps in reducing post-prandial glucose exertion. It achieves this through a number of mechanisms, including stimulating insulin release by pancreatic β-cells in a glucose-dependent manner; inhibition of glucagon release by pancreatic α-cells (also in a glucose-dependent manner); induction of central appetite suppression and by delaying gastric empting thereby inducing satiety and also reducing the rate of absorption of nutrients. However, GLP1 receptors have been described in a number of extra-pancreatic tissues, including the endothelium and the myocardium. This suggests that the physiological effects of GLP1 extend beyond post-prandial glucose control and raises the possibility that GLP1 might have cardiovascular effects. This is of importance in our understanding of incretin hormone physiology and especially because of the possible implications that it might have with regard to cardiovascular effects of incretin-based therapies, namely DPP-IV inhibitors (gliptins) and GLP1 analogues. This review analyzes the animal and human data on the effects of GLP1 on the cardiovascular system in health and in disease and the currently available data on cardiovascular effects of incretin-based therapies. It is the author's view that the physiological role of GLP1 is not only to minimize postprandial hypoglycaemia, but also protect against it.

Novel dual small-molecule HIV inhibitors: scaffolds and discovery strategies.

PubMed

Song, Anran; Yu, Haiqing; Wang, Changyuan; Zhu, Xingqi; Liu, Kexin; Ma, Xiaodong

2015-01-01

Searching for safe and effective treatments for HIV infection is still a great challenge worldwide in spite of the 27 marketed anti-HIV drugs and the powerful highly active antiretroviral therapy (HAART). As a promising prospect for generation of new HIV therapy drugs, multiple ligands (MDLs) were greatly focused on recently due to their lower toxicity, simplified dosing and patient adherence than single-target drugs. Till now, by disrupting two active sites or steps of HIV replications, a number of HIV dual inhibitors, such as CD4-gssucap120 inhibitors, CXCR4-gp20 inhibitors, RT-CXCR4 inhibitors, RT-protease inhibitors, RT-integrase inhibitors, and RTassociated functions inhibitors have been identified. Generally, these dual inhibitors were discovered mainly through screening approaches and design strategies. Of these compounds, the molecules bearing small skeletons exhibited strong anti-HIV activity and aroused great attention recently. Reviewing the progress of the dual small-molecule HIV inhibitors from the point of view of their scaffolds and discovery strategies will provide valuable information for producing more effective anti-HIV drugs. In this regard, novel dual small-molecule HIV inhibitors were illustrated, and their discovery paradigms as the major contents were also summarized in this manuscript.

Usefulness of a Novel Mobile Diabetes Prevention Program Delivery Platform With Human Coaching: 65-Week Observational Follow-Up.

PubMed

Michaelides, Andreas; Major, Jennifer; Pienkosz, Edmund; Wood, Meghan; Kim, Youngin; Toro-Ramos, Tatiana

2018-05-03

It is widely recognized that the prevalence of obesity and comorbidities including prediabetes and type 2 diabetes continue to increase worldwide. Results from a 24-week Diabetes Prevention Program (DPP) fully mobile pilot intervention were previously published showing promising evidence of the usefulness of DPP-based eHealth interventions on weight loss. This pilot study extends previous findings to evaluate weight loss results of core (up to week 16) and maintenance (postcore weeks) DPP interventions at 65 weeks from baseline. Originally, 140 participants were invited and 43 overweight or obese adult participants with a diagnosis of prediabetes signed up to receive a 24-week virtual DPP with human coaching through a mobile platform. At 65 weeks, this pilot study evaluates weight loss and engagement in maintenance participants by means of repeated measures analysis of variances and backward multiple linear regression to examine predictors of weight loss. Last observation carried forward was used for endpoint measurements. At 65 weeks, mean weight loss was 6.15% in starters who read 1 or more lessons per week on 4 or more core weeks, 7.36% in completers who read 9 or more lessons per week on core weeks, and 8.98% in maintenance completers who did any action in postcore weeks (all P<.001). Participants were highly engaged, with 80% (47/59) of the sample completing 9 lessons or more and 69% (32/47) of those completing the maintenance phase. In-app actions related to self-monitoring significantly predicted weight loss. In comparison to eHealth programs, this pilot study shows that a fully mobile DPP can produce transformative weight loss. A fully mobile DPP intervention resulted in significant weight loss and high engagement during the maintenance phase, providing evidence for long-term potential as an alternative to in-person DPP by removing many of the barriers associated with in-person and other forms of virtual DPP. ©Andreas Michaelides, Jennifer Major, Edmund Pienkosz Jr, Meghan Wood, Youngin Kim, Tatiana Toro-Ramos. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 03.05.2018.

SOP conservative (medical and mechanical) treatment of erectile dysfunction.

PubMed

Porst, Hartmut; Burnett, Arthur; Brock, Gerald; Ghanem, Hussein; Giuliano, Francois; Glina, Sidney; Hellstrom, Wayne; Martin-Morales, Antonio; Salonia, Andrea; Sharlip, Ira

2013-01-01

Erectile dysfunction (ED) is the most frequently treated male sexual dysfunction worldwide. ED is a chronic condition that exerts a negative impact on male self-esteem and nearly all life domains including interpersonal, family, and business relationships. The aim of this study is to provide an updated overview on currently used and available conservative treatment options for ED with a special focus on their efficacy, tolerability, safety, merits, and limitations including the role of combination therapies for monotherapy failures. The methods used were PubMed and MEDLINE searches using the following keywords: ED, phosphodiesterase type 5 (PDE5) inhibitors, oral drug therapy, intracavernosal injection therapy, transurethral therapy, topical therapy, and vacuum-erection therapy/constriction devices. Additionally, expert opinions by the authors of this article are included. Level 1 evidence exists that changes in sedentary lifestyle with weight loss and optimal treatment of concomitant diseases/risk factors (e.g., diabetes, hypertension, and dyslipidemia) can either improve ED or add to the efficacy of ED-specific therapies, e.g., PDE5 inhibitors. Level 1 evidence also exists that treatment of hypogonadism with total testosterone < 300 ng/dL (10.4 nmol/L) can either improve ED or add to the efficacy of PDE5 inhibitors. There is level 1 evidence regarding the efficacy and safety of the following monotherapies in a spectrum-wide range of ED populations: PDE5 inhibitors, intracavernosal injection therapy with prostaglandin E1 (PGE1, synonymous alprostadil) or vasoactive intestinal peptide (VIP)/phentolamine, and transurethral PGE1 therapy. There is level 2 evidence regarding the efficacy and safety of the following ED treatments: vacuum-erection therapy in a wide range of ED populations, oral L-arginine (3-5 g), topical PGE1 in special ED populations, intracavernosal injection therapy with papaverine/phentolamine (bimix), or papaverine/phentolamine/PGE1 (trimix) combination mixtures. There is level 3 evidence regarding the efficacy and safety of oral yohimbine in nonorganic ED. There is level 3 evidence that combination therapies of PDE5 inhibitors + either transurethral or intracavernosal injection therapy generate better efficacy rates than either monotherapy alone. There is level 4 evidence showing enhanced efficacy with the combination of vacuum-erection therapy + either PDE5 inhibitor or transurethral PGE1 or intracavernosal injection therapy. There is level 5 evidence (expert opinion) that combination therapy of PDE5 inhibitors + L-arginine or daily dosing of tadalafil + short-acting PDE5 inhibitors pro re nata may rescue PDE5 inhibitor monotherapy failures. There is level 5 evidence (expert opinion) that adding either PDE5 inhibitors or transurethral PGE1 may improve outcome of penile prosthetic surgery regarding soft (cold) glans syndrome. There is level 5 evidence (expert opinion) that the combination of PDE5 inhibitors and dapoxetine is effective and safe in patients suffering from both ED and premature ejaculation. © 2013 International Society for Sexual Medicine.

Saxagliptin/Dapagliflozin: A Review in Type 2 Diabetes Mellitus.

PubMed

Garnock-Jones, Karly P

2017-03-01

Saxagliptin/dapagliflozin fixed-dose combination tablets (Qtern ® ) are indicated in the EU for the improvement of glycaemic control in adults with type 2 diabetes mellitus (T2DM), either when treatment with metformin and/or a sulfonylurea plus a monocomponent of saxagliptin/dapagliflozin provides inadequate glycaemic control, or when the patient is already being treated with the free combination of saxagliptin + dapagliflozin. This narrative review summarizes pharmacological, efficacy and tolerability data relevant to the use of saxagliptin/dapagliflozin in this indication. The agents have complementary mechanisms of action, and saxagliptin/dapagliflozin fixed-dose combination tablets are bioequivalent to free combination of saxagliptin + dapagliflozin. In three phase III trials, saxagliptin + dapagliflozin + metformin was more effective at providing glycaemic control than saxagliptin + metformin or dapagliflozin + metformin in previously treated patients with T2DM and inadequate glycaemic control on metformin monotherapy or metformin plus one of the monocomponents. The combination is associated with decreased bodyweight and a low risk of hypoglycaemia. As the first dipeptidyl peptidase-4 (DPP-4) inhibitor/sodium-glucose co-transporter (SGLT2) inhibitor fixed-dose combination available in the EU for glycaemic control in patients with T2DM, saxagliptin/dapagliflozin is a useful new option in this setting.

Saxagliptin Upregulates Nesfatin-1 Secretion and Ameliorates Insulin Resistance and Metabolic Profiles in Type 2 Diabetes Mellitus.

PubMed

Chen, Kuanlin; Zhuo, Tiejun; Wang, Jian; Mei, Qing

2018-06-18

Saxagliptin as one of dipeptidyl peptidase-4 (DPP-4) inhibitors can effectively improve glycaemic control in type 2 diabetes mellitus, and nesfatin-1 is regarded as a very important factor in regulating feeding behavior and energy homeostasis. In this trial, we observed the effect of saxagliptin on regulating nesfatin-1 secretion and ameliorating insulin resistance and metabolic profiles in type 2 diabetes mellitus. One hundred two type 2 diabetes participants (M/F = 48/54) were investigated. Fifty-one (M/F = 24/27) of them as the treatment group were treated with oral glucose-lowering agents including saxagliptin, the other 51 (M/F = 24/27) as the control group were treated with oral glucose-lowering agents excluding any DPP-4 inhibitors. The parameters of serum nesfatin-1, C-peptide, homeostasis model assessment-β (HOMA-β) function, HOMA insulin resistance (HOMA-IR), glycosylated hemoglobin A1c (HbA1c), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), body mass index (BMI), and blood pressure (BP) at baseline, month 3, 6, and 12 were observed and compared respectively. Saxagliptin significantly upregulated nesfatin-1 secretion (P < 0.001 at 3-, 6-, and 12-months vs. baseline), increased serum C-peptide (P < 0.05, 0.001, and 0.001 at 3-, 6-, and 12-months vs. baseline), improved HOMA-IR and function of HOMA-β (P < 0.001 at 3-, 6-, and 12-months vs. baseline) and metabolic profiles (P < 0.001 with HbA1c at 3-, 6- and 12-months; P < 0.001 with LDL-C at 6- and 12-months; P < 0.001 and 0.01 with HDL-C at 6- and 12-months vs. baseline), declined BMI (P < 0.05 at 6- and 12-months vs. baseline) and BP (P < 0.001 with systolic BP (SBP), and mean BP at 6- and 12-months, P < 0.01 with diastolic BP at 6- and 12-months vs. baseline). Saxagliptin could upregulate nesfatin-1 secretion and ameliorate insulin resistance and metabolic profiles in type 2 diabetes mellitus. Saxagliptin had the potential to play fundamental by upregulating nesfatin-1 secretion besides lowering glucose by inhibiting the degradation of glucagon-like peptide-1.

Assessment of the pharmacokinetic interaction between the novel DPP-4 inhibitor linagliptin and a sulfonylurea, glyburide, in healthy subjects.

PubMed

Graefe-Mody, Ulrike; Rose, Peter; Ring, Arne; Zander, Kerstin; Iovino, Mario; Woerle, Hans-Juergen

2011-01-01

The aim of this study was to investigate the effect of the dipeptidyl peptidase-4 inhibitor linagliptin on the pharmacokinetics of glyburide (a CYP2C9 and CYP3A4 substrate) and vice versa. This randomized, open-label, three-period, two-way crossover study examined the effects of co-administration of multiple oral doses of linagliptin (5 mg/day × 6 days) and single doses of glyburide (1.75 mg/day × 1 day) on the relative bioavailability of either compound in healthy subjects (n = 20, age 18-55 years). Coadministration of glyburide did not alter the steady-state pharmacokinetics of linagliptin. Geometric mean ratios (GMRs) [90% CI] for (linagliptin + glyburide)/linagliptin AUC(τ,ss) and C(max,ss) were 101.7% [97.7-105.8%] and 100.8% [89.0-114.3%], respectively. For glyburide, there was a slight reduction in exposure of ∼14% when coadministered with linagliptin (GMRs [90% CI] for (glyburide + linagliptin)/glyburide AUC(0-∞) and C(max) were 85.7% [79.8-92.1%] and 86.2% [79.6-93.3%], respectively). However, this was not seen as clinically relevant due to the absence of a reliable dose-response relationship and the known large pharmacokinetic interindividual variability of glyburide. These results further support the assumption that linagliptin is not a clinically relevant inhibitor of CYP2C9 or CYP3A4 in vivo. Coadministration of linagliptin and glyburide had no clinically relevant effect on the pharmacokinetics of linagliptin or glyburide. Both agents were well tolerated and can be administered together without the need for dosage adjustments.

Tuning the electrical conductance of metalloporphyrin supramolecular wires

NASA Astrophysics Data System (ADS)

Noori, Mohammed; Aragonès, Albert C.; di Palma, Giuseppe; Darwish, Nadim; Bailey, Steven W. D.; Al-Galiby, Qusiy; Grace, Iain; Amabilino, David B.; González-Campo, Arántzazu; Díez-Pérez, Ismael; Lambert, Colin J.

2016-11-01

In contrast with conventional single-molecule junctions, in which the current flows parallel to the long axis or plane of a molecule, we investigate the transport properties of M(II)-5,15-diphenylporphyrin (M-DPP) single-molecule junctions (M=Co, Ni, Cu, or Zn divalent metal ions), in which the current flows perpendicular to the plane of the porphyrin. Novel STM-based conductance measurements combined with quantum transport calculations demonstrate that current-perpendicular-to-the-plane (CPP) junctions have three-orders-of-magnitude higher electrical conductances than their current-in-plane (CIP) counterparts, ranging from 2.10-2 G0 for Ni-DPP up to 8.10-2 G0 for Zn-DPP. The metal ion in the center of the DPP skeletons is strongly coordinated with the nitrogens of the pyridyl coated electrodes, with a binding energy that is sensitive to the choice of metal ion. We find that the binding energies of Zn-DPP and Co-DPP are significantly higher than those of Ni-DPP and Cu-DPP. Therefore when combined with its higher conductance, we identify Zn-DPP as the favoured candidate for high-conductance CPP single-molecule devices.

Degradation and Stabilization of Peptide Hormones in Human Blood Specimens

PubMed Central

Yi, Jizu; Warunek, David; Craft, David

2015-01-01

Plasma hormone peptides, including GLP-1, GIP, Glucagon, and OXM, possess multiple physiological roles and potential therapeutic and diagnostic utility as biomarkers in the research of metabolic disorders. These peptides are subject to proteolytic degradation causing preanalytical variations. Stabilization for accurate quantitation of these active peptides in ex vivo blood specimens is essential for drug and biomarker development. We investigated the protease-driven instability of these peptides in conventional serum, plasma, anticoagulated whole blood, as well as whole blood and plasma stabilized with protease inhibitors. The peptide was monitored by both time-course Matrix-Assisted Laser Desorption Ionization Time-to-Flight Mass Spectrometry (MALDI –TOF MS) and Ab-based assay (ELISA or RIA). MS enabled the identification of proteolytic fragments. In non-stabilized blood samples, the results clearly indicated that dipeptidyl peptidase-IV (DPP-IV) removed the N-terminal two amino acid residues from GLP-1, GIP and OXM(1-37) and not-yet identified peptidase(s) cleave(s) the full-length OXM(1-37) and its fragments. DPP-IV also continued to remove two additional N-terminal residues of processed OXM(3–37) to yield OXM(5–37). Importantly, both DPP-IV and other peptidase(s) activities were inhibited efficiently by the protease inhibitors included in the BD P800* tube. There was preservation of GLP-1, GIP, OXM and glucagon in the P800 plasma samples with half-lives > 96, 96, 72, and 45 hours at room temperature (RT), respectively. In the BD P700* plasma samples, the stabilization of GLP-1 was also achieved with half-life > 96 hours at RT. The stabilization of these variable peptides increased their utility in drug and/or biomarker development. While stability results of GLP-1 obtained with Ab-based assay were consistent with those obtained by MS analysis, the Ab-based results of GIP, Glucagon, and OXM did not reflect the time-dependent degradations revealed by MS analysis. Therefore, we recommended characterizing the degradation of the peptide using the MS-based method when investigating the stability of a specific peptide. PMID:26222180

A grape seed extract increases active glucagon-like peptide-1 levels after an oral glucose load in rats.

PubMed

González-Abuín, Noemi; Martínez-Micaelo, Neus; Margalef, Maria; Blay, Mayte; Arola-Arnal, Anna; Muguerza, Begoña; Ardévol, Anna; Pinent, Montserrat

2014-09-01

We have previously reported that procyanidins, a class of flavonoids, improve glycemia and exert an incretin-like effect, which was linked to their proven inhibitory effect on the dipeptidyl-peptidase 4 (DPP4) activity. However, their actual effect on incretin levels has not been reported yet. Therefore, in the present study we have evaluated whether a grape seed extract enriched in procyanidins (GSPE) modulates plasma incretin levels and attempted to determine the mechanisms involved. An acute GSPE treatment in healthy Wistar female rats prior to an oral glucose load induced an increase in plasma active glucagon-like peptide-1 (GLP-1), which was accompanied by an increase in the plasma insulin/glucose ratio and a simultaneous decrease in glucose levels. In agreement with our previous studies, the intestinal DPP4 activity was inhibited by the GSPE treatment. We have also assayed in vitro whether this inhibition occurs in inner intestinal tissues close to GLP-1-producing cells, such as the endothelium of the capillaries. We have found that the main compounds absorbed by intestinal CaCo-2 cells after an acute treatment with GSPE are catechin, epicatechin, B2 dimer and gallic acid, and that they inhibit the DPP4 activity in endothelial HUVEC cells in an additive way. Moreover, an increase in plasma total GLP-1 levels was found, suggesting an increase in GLP-1 secretion. In conclusion, our results show that GSPE improves glycemia through its action on GLP-1 secretion and on the inhibition of the inner intestinal DPP4 activity, leading to an increase in active GLP-1 levels, which, in turn, may affect the insulin release.

Identification of peptidase substrates in human plasma by FTMS based differential mass spectrometry

NASA Astrophysics Data System (ADS)

Yates, Nathan A.; Deyanova, Ekaterina G.; Geissler, Wayne; Wiener, Matthew C.; Sachs, Jeffrey R.; Wong, Kenny K.; Thornberry, Nancy A.; Sinha Roy, Ranabir; Settlage, Robert E.; Hendrickson, Ronald C.

2007-01-01

Approximately 2% of the human genome encodes for proteases. Unfortunately, however, the biological roles of most of these enzymes remain poorly defined, since the physiological substrates are typically unknown and are difficult to identify using traditional methods. We have developed a proteomics experiment based on FTMS profiling and differential mass spectrometry (dMS) to identify candidate endogenous substrates of proteases using fractionated human plasma as the candidate substrate pool. Here we report proof-of-concept experiments for identifying in vitro substrates of aminopeptidase P2, (APP2) and dipeptidyl peptidase 4 (DPP-4), a peptidase of therapeutic interest for the treatment of type 2 diabetes. For both proteases, previously validated peptide substrates spiked into the human plasma pool were identified. Of note, the differential mass spectrometry experiments also identified novel substrates for each peptidase in the subfraction of human plasma. Targeted MS/MS analysis of these peptides in the complex human plasma pool and manual confirmation of the amino acid sequences led to the identification of these substrates. The novel DPP-4 substrate EPLGRQLTSGP was chemically synthesized and cleavage kinetics were determined in an in vitro DPP-4 enzyme assay. The apparent second order rate constant (kcat/KM) for DPP-4-mediated cleavage was determined to be 2.3 x 105 M-1 s-1 confirming that this peptide is efficiently processed by the peptidase in vitro. Collectively, these results demonstrate that differential mass spectrometry has the potential to identify candidate endogenous substrates of target proteases from a human plasma pool. Importantly, knowledge of the endogenous substrates can provide useful insight into the biology of these enzymes and provides useful biomarkers for monitoring their activity in vivo.

Uncoupling protein-2 mediates DPP-4 inhibitor-induced restoration of endothelial function in hypertension through reducing oxidative stress.

PubMed

Liu, Limei; Liu, Jian; Tian, Xiao Yu; Wong, Wing Tak; Lau, Chi Wai; Xu, Aimin; Xu, Gang; Ng, Chi Fai; Yao, Xiaoqiang; Gao, Yuansheng; Huang, Yu

2014-10-10

Although uncoupling protein 2 (UCP2) negatively regulates intracellular reactive oxygen species (ROS) production and protects vascular function, its participation in vascular benefits of drugs used to treat cardiometabolic diseases is largely unknown. This study investigated whether UCP2 and associated oxidative stress reduction contribute to the improvement of endothelial function by a dipeptidyl peptidase-4 inhibitor, sitagliptin, in hypertension. Pharmacological inhibition of cyclooxygenase-2 (COX-2) but not COX-1 prevented endothelial dysfunction, and ROS scavengers reduced COX-2 mRNA and protein expression in spontaneously hypertensive rats (SHR) renal arteries. Angiotensin II (Ang II) evoked endothelium-dependent contractions (EDCs) in C57BL/6 and UCP2 knockout (UCP2KO) mouse aortae. Chronic sitagliptin administration attenuated EDCs in SHR arteries and Ang II-infused C57BL/6 mouse aortae and eliminated ROS overproduction in SHR arteries, which were reversed by glucagon-like peptide 1 receptor (GLP-1R) antagonist exendin 9-39, AMP-activated protein kinase (AMPK)α inhibitor compound C, and UCP2 inhibitor genipin. By contrast, sitagliptin unaffected EDCs in Ang II-infused UCP2KO mice. Sitagliptin increased AMPKα phosphorylation, upregulated UCP2, and downregulated COX-2 expression in arteries from SHR and Ang II-infused C57BL/6 mice. Importantly, exendin 9-39, compound C, and genipin reversed the inhibitory effect of GLP-1R agonist exendin-4 on Ang II-stimulated mitochondrial ROS rises in SHR endothelial cells. Moreover, exendin-4 improved the endothelial function of renal arteries from SHR and hypertensive patients. We elucidate for the first time that UCP2 serves as an important signal molecule in endothelial protection conferred by GLP-1-related agents. UCP2 could be a useful target in treating hypertension-related vascular events. UCP2 inhibits oxidative stress and downregulates COX-2 expression through GLP-1/GLP-1R/AMPKα cascade.

A Formative Evaluation of a Diabetes Prevention Program Using the RE-AIM Framework in a Learning Health Care System, Utah, 2013-2015.

PubMed

Brunisholz, Kimberly D; Kim, Jaewhan; Savitz, Lucy A; Hashibe, Mia; Gren, Lisa H; Hamilton, Sharon; Huynh, Kelly; Joy, Elizabeth A

2017-07-20

Evaluation of interventions can help to close the gap between research and practice but seldom takes place during implementation. Using the RE-AIM framework, we conducted a formative evaluation of the first year of the Intermountain Healthcare Diabetes Prevention Program (DPP). Adult patients who met the criteria for prediabetes (HbA1c of 5.70%-6.49% or fasting plasma glucose of 100-125 mg/dL) were attributed to a primary care provider from August 1, 2013, through July 31, 2014. Physicians invited eligible patients to participate in the program during an office visit. We evaluated 1) reach, with data on patient eligibility, participation, and representativeness; 2) effectiveness, with data on attaining a 5% weight loss; 3) adoption, with data on providers and clinics that referred patients to the program; and 4) implementation, with data on patient encounters. We did not measure maintenance. Of the 6,862 prediabetes patients who had an in-person office visit with their provider, 8.4% of eligible patients enrolled. Likelihood of participation was higher among patients who were female, aged 70 years or older, or overweight; had depression and higher weight at study enrollment; or were prescribed metformin. DPP participants were more likely than nonparticipants to achieve a 5% weight loss (odds ratio, 1.70; 95% confidence interval, 1.29-2.25; P < .001). Providers from 7 of 8 regions referred patients to the DPP; 174 providers at 53 clinics enrolled patients. The mean number of DPP counseling encounters per patient was 2.3 (range, 1-16). The RE-AIM framework was useful for estimating the formative impact (ie, reach, effectiveness, adoption, and implementation fidelity) of a DPP-based lifestyle intervention deployed in a learning health care system.

Heteroleptic copper(I) complexes prepared from phenanthroline and bis-phosphine ligands.

PubMed

Kaeser, Adrien; Mohankumar, Meera; Mohanraj, John; Monti, Filippo; Holler, Michel; Cid, Juan-José; Moudam, Omar; Nierengarten, Iwona; Karmazin-Brelot, Lydia; Duhayon, Carine; Delavaux-Nicot, Béatrice; Armaroli, Nicola; Nierengarten, Jean-François

2013-10-21

Preparation of [Cu(NN)(PP)](+) derivatives has been systematically investigated starting from two libraries of phenanthroline (NN) derivatives and bis-phosphine (PP) ligands, namely, (A) 1,10-phenanthroline (phen), neocuproine (2,9-dimethyl-1,10-phenanthroline, dmp), bathophenanthroline (4,7-diphenyl-1,10-phenanthroline, Bphen), 2,9-diphenethyl-1,10-phenanthroline (dpep), and 2,9-diphenyl-1,10-phenanthroline (dpp); (B) bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,2-bis(diphenylphosphino)benzene (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppFc), and bis[(2-diphenylphosphino)phenyl] ether (POP). Whatever the bis-phosphine ligand, stable heteroleptic [Cu(NN)(PP)](+) complexes are obtained from the 2,9-unsubstituted-1,10-phenanthroline ligands (phen and Bphen). By contrast, heteroleptic complexes obtained from dmp and dpep are stable in the solid state, but a dynamic ligand exchange reaction is systematically observed in solution, and the homoleptic/heteroleptic ratio is highly dependent on the bis-phosphine ligand. Detailed analysis revealed that the dynamic equilibrium resulting from ligand exchange reactions is mainly influenced by the relative thermodynamic stability of the different possible complexes. Finally, in the case of dpp, only homoleptic complexes were obtained whatever the bis-phosphine ligand. Obviously, steric effects resulting from the presence of the bulky phenyl rings on the dpp ligand destabilize the heteroleptic [Cu(NN)(PP)](+) complexes. In addition to the remarkable thermodynamic stability of [Cu(dpp)2]BF4, this negative steric effect drives the dynamic complexation scenario toward almost exclusive formation of homoleptic [Cu(NN)2](+) and [Cu(PP)2](+) complexes. This work provides the definitive rationalization of the stability of [Cu(NN)(PP)](+) complexes, marking the way for future developments in this field.

Involvement of DPP IV/CD26 in cutaneous wound healing process in mice.

PubMed

Baticic Pucar, Lara; Pernjak Pugel, Ester; Detel, Dijana; Varljen, Jadranka

2017-01-01

Dipeptidyl peptidase IV (DPP IV/CD26) is a widely distributed multifunctional protein that plays a significant role in different physiological as well as pathological processes having a broad spectrum of bioactive substrates and immunomodulative properties. It has potential influence on different processes crucial for wound healing, including cell adhesion, migration, apoptosis, and extracellular matrix degradation. However, despite its known enzymatic and immunomodulative functions, limited data characterize the role of DPP IV/CD26 in cutaneous wound healing mechanisms. The aim of this study was to investigate the process of wound healing in conditions of CD26 deficiency in order to obtain better insights on the role of DPP IV/CD26 in cutaneous regeneration. Experimental wounds were made on the dorsal part of CD26 deficient (CD26 -/- ) and wild-type mice (C57BL/6). The process of cutaneous wound healing was monitored on defined time schedule postwounding by macroscopic, microscopic, and biochemical analyses. Obtained results revealed a better rate of wound closure, revascularization and cell proliferation in CD26 -/- mice, with enhanced local expression of hypoxia-inducible factor 1α and vascular endothelial growth factor. CD26 deficiency induced prompt macrophage recruitment at the site of skin damage but did not influence mobilization of T-cells in comparison with wild-type mice. CD26 -/- mice have significantly higher values of IP-10 in serum and control skins compared with wild-type mice but values in wounds did not differ significantly on days 2, 4, and 7 of wound healing. DPP IV/CD26 activity was found to be decreased 4 days postwounding in serum and 2, 4, and 7 days postwounding in wounds of wild-type animals compared with control skins. These findings contribute to better understanding of wound healing mechanisms and could give a support in finding new therapeutic approaches for wound healing and tissue regeneration. © 2016 by the Wound Healing Society.

Current and emerging topical therapies for atopic dermatitis.

PubMed

Udkoff, Jeremy; Waldman, Andrea; Ahluwalia, Jusleen; Borok, Jenna; Eichenfield, Lawrence F

The pathogenesis of atopic dermatitis (AD) involves epidermal barrier dysfunction and T helper cell type 2 (T h 2) lymphocyte-driven inflammation. Cytokines, such as interleukin 4 (IL-4) and IL-13, are important in this reaction. They stimulate B cells to produce immunoglobulin E, causing atopic disease. This process has been well characterized, and new therapies for AD, such as phosphodiesterase 4 (PDE-4) inhibitors, T h 2-expressed chemoattractant receptor-homologous molecule antagonists, and Janus kinase inhibitors, work by antagonizing this cellular pathway. Recently, there have been many advances in treatment strategies and novel therapies for AD. This review summarizes the clinical evidence supporting the use of current and emerging topical treatments for AD, as well as their safety and efficacy profiles. Crisaborole, a novel PDE-4 inhibitor, is of particular note because phase III clinical trials were recently completed, as summarized here. It is prudent for dermatologists to be current with updates in the field because therapies are constantly changing. In addition to the academic interest, this results in improvement of patient care and advancement of the field. Copyright © 2017 Elsevier Inc. All rights reserved.

Antidepressant medicine use and risk of developing diabetes during the diabetes prevention program and diabetes prevention program outcomes study.

PubMed

Rubin, Richard R; Ma, Yong; Peyrot, Mark; Marrero, David G; Price, David W; Barrett-Connor, Elizabeth; Knowler, William C

2010-12-01

To assess the association between antidepressant medicine use and risk of developing diabetes during the Diabetes Prevention Program (DPP) and Diabetes Prevention Program Outcomes Study (DPPOS). DPP/DPPOS participants were assessed for diabetes every 6 months and for antidepressant use every 3 months in DPP and every 6 months in DPPOS for a median 10.0-year follow-up. Controlled for factors associated with diabetes risk, continuous antidepressant use compared with no use was associated with diabetes risk in the placebo (adjusted hazard ratio 2.34 [95% CI 1.32-4.15]) and lifestyle (2.48 [1.45-4.22]) arms, but not in the metformin arm (0.55 [0.25-1.19]). Continuous antidepressant use was significantly associated with diabetes risk in the placebo and lifestyle arms. Measured confounders and mediators did not account for this association, which could represent a drug effect or reflect differences not assessed in this study between antidepressant users and nonusers.

Bacterial protease uses distinct thermodynamic signatures for substrate recognition.

PubMed

Bezerra, Gustavo Arruda; Ohara-Nemoto, Yuko; Cornaciu, Irina; Fedosyuk, Sofiya; Hoffmann, Guillaume; Round, Adam; Márquez, José A; Nemoto, Takayuki K; Djinović-Carugo, Kristina

2017-06-06

Porphyromonas gingivalis and Porphyromonas endodontalis are important bacteria related to periodontitis, the most common chronic inflammatory disease in humans worldwide. Its comorbidity with systemic diseases, such as type 2 diabetes, oral cancers and cardiovascular diseases, continues to generate considerable interest. Surprisingly, these two microorganisms do not ferment carbohydrates; rather they use proteinaceous substrates as carbon and energy sources. However, the underlying biochemical mechanisms of their energy metabolism remain unknown. Here, we show that dipeptidyl peptidase 11 (DPP11), a central metabolic enzyme in these bacteria, undergoes a conformational change upon peptide binding to distinguish substrates from end products. It binds substrates through an entropy-driven process and end products in an enthalpy-driven fashion. We show that increase in protein conformational entropy is the main-driving force for substrate binding via the unfolding of specific regions of the enzyme ("entropy reservoirs"). The relationship between our structural and thermodynamics data yields a distinct model for protein-protein interactions where protein conformational entropy modulates the binding free-energy. Further, our findings provide a framework for the structure-based design of specific DPP11 inhibitors.

Dpp signaling inhibits proliferation in the Drosophila wing by Omb-dependent regional control of bantam.

PubMed

Zhang, Xubo; Luo, Dan; Pflugfelder, Gert O; Shen, Jie

2013-07-01

The control of organ growth is a fundamental aspect of animal development but remains poorly understood. The morphogen Dpp has long been considered as a general promoter of cell proliferation during Drosophila wing development. It is an ongoing debate whether the Dpp gradient is required for the uniform cell proliferation observed in the wing imaginal disc. Here, we investigated how the Dpp signaling pathway regulates proliferation during wing development. By systematic manipulation of Dpp signaling we observed that it controls proliferation in a region-specific manner: Dpp, via omb, promoted proliferation in the lateral and repressed proliferation in the medial wing disc. Omb controlled the regional proliferation rate by oppositely regulating transcription of the microRNA gene bantam in medial versus lateral wing disc. However, neither the Dpp nor Omb gradient was essential for uniform proliferation along the anteroposterior axis.

Sepsis-induced activation of endogenous GLP-1 system is enhanced in type 2 diabetes.

PubMed

Perl, Sivan H; Bloch, Olga; Zelnic-Yuval, Dana; Love, Itamar; Mendel-Cohen, Lior; Flor, Hadar; Rapoport, Micha J

2018-05-01

High levels of circulating GLP-1 are associated with severity of sepsis in critically ill nondiabetic patients. Whether patients with type 2 diabetes (T2D) display different activation of the endogenous GLP-1 system during sepsis and whether it is affected by diabetes-related metabolic parameters are not known. Serum levels of GLP-1 (total and active forms) and its inhibitor enzyme sDPP-4 were determined by ELISA on admission and after 2 to 4 days in 37 sepsis patients with (n = 13) and without T2D (n = 24) and compared to normal healthy controls (n = 25). Correlations between GLP-1 system activation and clinical, inflammatory, and diabetes-related metabolic parameters were performed. A 5-fold (P < .001) and 2-fold (P < .05) increase in active and total GLP-1 levels, respectively, were found on admission as compared to controls. At 2 to 4 days from admission, the level of active GLP-1 forms in surviving patients were decreased significantly (P < .005), and positively correlated with inflammatory marker CRP (r = 0.33, P = .05). T2D survivors displayed a similar but more enhanced pattern of GLP-1 response than nondiabetic survivors. Nonsurvivors demonstrate an early extreme increase of both total and active GLP-1 forms, 9.5-fold and 5-fold, respectively (P < .05). The initial and late levels of circulating GLP-1 inhibitory enzyme sDPP-4 were twice lower in all studied groups (P < .001), compared with healthy controls. Taken together, these data indicate that endogenous GLP-1 system is activated during sepsis. Patients with T2D display an enhanced and prolonged activation as compared to nondiabetic patients. Extreme early increased GLP-1 levels during sepsis indicate poor prognosis. Copyright © 2018 John Wiley & Sons, Ltd.

Women Veterans’ Experience With a Web-Based Diabetes Prevention Program: A Qualitative Study to Inform Future Practice

PubMed Central

Ertl, Kristyn; Schneider, Jessica; Vasti, Elena; Makki, Fatima; Richardson, Caroline; Havens, Kathryn; Damschroder, Laura

2015-01-01

Background Diabetes prevention is a national goal and particularly important in the Veterans Health Administration (VHA) where 1 in 4 veterans has diabetes. There is growing evidence to support the use of Web-based diabetes prevention program (DPP) interventions, shown to be as effective and often more feasible than in-person interventions. Objective Our primary objective was to qualitatively explore women veterans’ early experiences with a Web-based DPP intervention. Our secondary objective was to estimate weight loss, participation, and engagement to provide context for our qualitative findings. Methods We conducted and analyzed semistructured interviews and collected data on weight change, participation, and engagement. A total of 17 women veterans with prediabetes from a Midwest VA Women’s Health Clinic were eligible to participate; 15 completed interviews. Results Participants perceived the DPP program as an appealing way of initiating lifestyle changes and made them feel accountable in achieving their daily goals. The online program was convenient because it could be accessed at any time, and many found that it integrated well into daily life. However, some did not like the logging aspect and some found it to be too impersonal. Participants logged in a mean 76 times, posted a mean 46 group messages, and sent a mean 20.5 private messages to the health coach over 16 weeks. Participants lost 5.24% of baseline weight, and 82% (14/17) of participants completed at least 9 of 16 core modules. Conclusions Women veterans’ early experiences with a Web-based DPP intervention were generally positive. Accountability and convenience were key enabling factors for participation and engagement. A Web-based DPP intervention appears to be a promising means of translating the DPP for women veterans with prediabetes. PMID:26006697

Serum protease activity in chronic kidney disease patients: The GANI_MED renal cohort

PubMed Central

Wolke, Carmen; Teumer, Alexander; Endlich, Karlhans; Endlich, Nicole; Rettig, Rainer; Stracke, Sylvia; Fiene, Beate; Aymanns, Simone; Felix, Stephan B; Hannemann, Anke

2016-01-01

Serum or plasma proteases have been associated with various diseases including cancer, inflammation, or reno-cardiovascular diseases. We aimed to investigate whether the enzymatic activities of serum proteases are associated with the estimated glomerular filtration rate (eGFR) in patients with different stages of chronic kidney disease (CKD). Our study population comprised 268 participants of the “Greifswald Approach to Individualized Medicine” (GANI_MED) cohort. Enzymatic activity of aminopeptidase A, aminopeptidase B, alanyl (membrane) aminopeptidase, insulin-regulated aminopeptidase, puromycin-sensitive aminopeptidase, leucine aminopeptidase 3, prolyl-endopeptidase (PEP), dipeptidyl peptidase 4 (DPP4), angiotensin I-converting enzyme, and angiotensin I-converting enzyme 2 (ACE2) proteases was measured in serum. Linear regression of the respective protease was performed on kidney function adjusted for age and sex. Kidney function was modeled either by the continuous Modification of Diet in Renal Disease (MDRD)-based eGFR or dichotomized by eGFR < 15 mL/min/1.73 m2 or <45 mL/min/1.73 m2, respectively. Results with a false discovery rate below 0.05 were deemed statistically significant. Among the 10 proteases investigated, only the activities of ACE2 and DPP4 were correlated with eGFR. Patients with lowest eGFR exhibited highest DPP4 and ACE2 activities. DPP4 and PEP were correlated with age, but all other serum protease activities showed no associations with age or sex. Our data indicate that ACE2 and DPP4 enzymatic activity are associated with the eGFR in patients with CKD. This finding distinguishes ACE2 and DPP4 from other serum peptidases analyzed and clearly indicates that further analyses are warranted to identify the precise role of these serum ectopeptidases in the pathogenesis of CKD and to fully elucidate underlying molecular mechanisms. Impact statement • Renal and cardiac diseases are very common and often occur concomitantly, resulting in increased morbidity and mortality. Understanding of molecular mechanisms linking both diseases is limited, available fragmentary data point to a role of the renin–angiotensin system (RAS) and, in particular, Ras-related peptidases. • Here, a comprehensive analysis of serum peptidase activities in patients with different stages of chronic kidney disease (CKD) is presented, with special emphasis given to RAS peptidases • The serum activities of the peptidases angiotensin I-converting enzyme 2 and dipeptidyl peptidase 4 were identified as closely associated with kidney function, specifically with the estimated glomerular filtration rate. The findings are discussed in the context of available data suggesting protective roles for both enzymes in reno-cardiac diseases. • The data add to our understanding of pathomechanisms underlying development and progression of CKD and indicate that both enzymes might represent potential pharmacological targets for the preservation of renal function. PMID:28038565

Serum protease activity in chronic kidney disease patients: The GANI_MED renal cohort.

PubMed

Wolke, Carmen; Teumer, Alexander; Endlich, Karlhans; Endlich, Nicole; Rettig, Rainer; Stracke, Sylvia; Fiene, Beate; Aymanns, Simone; Felix, Stephan B; Hannemann, Anke; Lendeckel, Uwe

2017-03-01

Serum or plasma proteases have been associated with various diseases including cancer, inflammation, or reno-cardiovascular diseases. We aimed to investigate whether the enzymatic activities of serum proteases are associated with the estimated glomerular filtration rate (eGFR) in patients with different stages of chronic kidney disease (CKD). Our study population comprised 268 participants of the "Greifswald Approach to Individualized Medicine" (GANI_MED) cohort. Enzymatic activity of aminopeptidase A, aminopeptidase B, alanyl (membrane) aminopeptidase, insulin-regulated aminopeptidase, puromycin-sensitive aminopeptidase, leucine aminopeptidase 3, prolyl-endopeptidase (PEP), dipeptidyl peptidase 4 (DPP4), angiotensin I-converting enzyme, and angiotensin I-converting enzyme 2 (ACE2) proteases was measured in serum. Linear regression of the respective protease was performed on kidney function adjusted for age and sex. Kidney function was modeled either by the continuous Modification of Diet in Renal Disease (MDRD)-based eGFR or dichotomized by eGFR < 15 mL/min/1.73 m 2 or <45 mL/min/1.73 m 2 , respectively. Results with a false discovery rate below 0.05 were deemed statistically significant. Among the 10 proteases investigated, only the activities of ACE2 and DPP4 were correlated with eGFR. Patients with lowest eGFR exhibited highest DPP4 and ACE2 activities. DPP4 and PEP were correlated with age, but all other serum protease activities showed no associations with age or sex. Our data indicate that ACE2 and DPP4 enzymatic activity are associated with the eGFR in patients with CKD. This finding distinguishes ACE2 and DPP4 from other serum peptidases analyzed and clearly indicates that further analyses are warranted to identify the precise role of these serum ectopeptidases in the pathogenesis of CKD and to fully elucidate underlying molecular mechanisms. Impact statement • Renal and cardiac diseases are very common and often occur concomitantly, resulting in increased morbidity and mortality. Understanding of molecular mechanisms linking both diseases is limited, available fragmentary data point to a role of the renin-angiotensin system (RAS) and, in particular, Ras-related peptidases. • Here, a comprehensive analysis of serum peptidase activities in patients with different stages of chronic kidney disease (CKD) is presented, with special emphasis given to RAS peptidases • The serum activities of the peptidases angiotensin I-converting enzyme 2 and dipeptidyl peptidase 4 were identified as closely associated with kidney function, specifically with the estimated glomerular filtration rate. The findings are discussed in the context of available data suggesting protective roles for both enzymes in reno-cardiac diseases. • The data add to our understanding of pathomechanisms underlying development and progression of CKD and indicate that both enzymes might represent potential pharmacological targets for the preservation of renal function.

Targeting the cyclin D-cyclin-dependent kinase (CDK) 4/6-retinoblastoma pathway with selective CDK 4/6 inhibitors in hormone receptor-positive breast cancer: rationale, current status, and future directions.

PubMed

Spring, Laura; Bardia, Aditya; Modi, Shanu

2016-01-01

Dysregulation of the cyclin D-cyclin-dependent kinase (CDK) 4/6-INK4-retinoblastoma (Rb) pathway is an important contributor to endocrine therapy resistance. Recent clinical development of selective inhibitors of CDK4 and CDK6 kinases has led to renewed interest in cell cycle regulators, following experience with relatively non-selective pan-CDK inhibitors that often resulted in limited activity and poor safety profiles in the clinic. The highly selective oral CDK 4/6 inhibitors palbociclib (PD0332991), ribociclib (LEE011), and abemaciclib (LY2835219) are able to inhibit the proliferation of Rb-positive tumor cells and have demonstrated dose-dependent growth inhibition in ER+ breast cancer models. In metastatic breast cancer, all three agents are being explored in combination with endocrine therapy in Phase III studies. Results so far indicated promising efficacy and manageable safety profiles, and led to the FDA approval of palbociclib. Phase II-III studies of these agents, in combination with endocrine therapy, are also underway in early breast cancer in the neoadjuvant and adjuvant settings. Selective CDK 4/6 inhibitors are also being investigated with other targeted agents or chemotherapy in the advanced setting. This article reviews the rationale for targeting cyclin D-CDK 4/6 in hormone receptor-positive (HR+) breast cancer, provides an overview of the available preclinical and clinical data with CDK 4/6 inhibitors in breast cancer to date, and summarizes the main features of ongoing clinical trials of these new agents in breast cancer. Future trials evaluating further combination strategies with CDK 4/6 backbone and translational studies refining predictive biomarkers are needed to help personalize the optimal treatment regimen for individual patients with ER+ breast cancer.

[Current Status of Targeted Treatment in Breast Cancer].

PubMed

Seiffert, Katharina; Schmalfeldt, Barbara; Müller, Volkmar

2017-11-01

Within the last years, significant improvements have been achieved in breast cancer treatment, particularly with the development of targeted therapies. Major progress has been made in identifying the drivers malignant growth in oestrogen-receptor-positive breast cancer and the mechanisms of resistance to endocrine therapy. This progress has translated into several targeted therapies that enhance the efficacy of endocrine therapy; inhibitors of the cyclin-dependent kinases CDK4 and CDK6 like palbociclib and inhibitors of mTOR substantially improve progression-free survival. For patients with HER2-positive disease the addition of Pertuzumab to Trastuzumab in combination with chemotherapy has been a significant improvement in anti-HER2 therapy in early as well as metastatic breast cancer. Evidence-based further line therapy options in the metastatic setting include T-DM1 and in later lines Lapatinib. For triple negative disease the angiogenesis inhibitor Bevacizumab is approved, which increases progression free survival. Immune checkpoint inhibitors, PARP-inhibitors or anti-androgens represent promising strategies, all of which are currently being evaluated in clinical trials. The development of predictive biomarkers to guide targeted therapies is still the subject of research. © Georg Thieme Verlag KG Stuttgart · New York.

Angioedema Triggered by Medication Blocking the Renin/Angiotensin System: Retrospective Study Using the French National Pharmacovigilance Database.

PubMed

Faisant, Charles; Armengol, Guillaume; Bouillet, Laurence; Boccon-Gibod, Isabelle; Villier, Céline; Lévesque, Hervé; Cottin, Judith; Massy, Nathalie; Benhamou, Ygal

2016-01-01

Bradykinin-mediated angioedema (AE) is a rare side effect of some medications, including angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB). In France, side-effects to treatments are reported to the national pharmacovigilance database. The national MedDRA database was searched using the term "angioedema". Patients were included if they met the clinical criteria corresponding to bradykinin-mediated AE, if their C1-inhibitor levels were normal, and if they were treated with an ACEi or an ARB. 7998 cases of AE were reported between 1994 and 2013. Among these, 112 met the criteria for bradykinin-mediated AE with normal C1-inhibitor levels. On the 112 drug-AE, patients were treated with an ARB in 21% of cases (24 patients), or an ACEi in 77% of cases (88 patients), in combination with another treatment in 17 cases (mTORi for 3 patients, iDPP-4 for 1 patient, hormonal treatment for 7 patients). ENT involvement was reported in 90% of cases (tongue: 48.2%, larynx: 23.2%). The median duration of treatment before the first attack was 720 days, and the mean duration of attacks was 36.6 h. Forty-one percent (19/46) of patients relapsed after discontinuing treatment. Angioedema triggered by medication blocking the renin/angiotensin system is rare but potentially severe, with a high risk of recurrence despite cessation of the causative drug.

Micro-Environmental Signature of The Interactions between Druggable Target Protein, Dipeptidyl Peptidase-IV, and Anti-Diabetic Drugs.

PubMed

Chakraborty, Chiranjib; Mallick, Bidyut; Sharma, Ashish Ranjan; Sharma, Garima; Jagga, Supriya; Doss, C George Priya; Nam, Ju-Suk; Lee, Sang-Soo

2017-01-01

Druggability of a target protein depends on the interacting micro-environment between the target protein and drugs. Therefore, a precise knowledge of the interacting micro-environment between the target protein and drugs is requisite for drug discovery process. To understand such micro-environment, we performed in silico interaction analysis between a human target protein, Dipeptidyl Peptidase-IV (DPP-4), and three anti-diabetic drugs (saxagliptin, linagliptin and vildagliptin). During the theoretical and bioinformatics analysis of micro-environmental properties, we performed drug-likeness study, protein active site predictions, docking analysis and residual interactions with the protein-drug interface. Micro-environmental landscape properties were evaluated through various parameters such as binding energy, intermolecular energy, electrostatic energy, van der Waals'+H-bond+desolvo energy (E VHD ) and ligand efficiency (LE) using different in silico methods. For this study, we have used several servers and software, such as Molsoft prediction server, CASTp server, AutoDock software and LIGPLOT server. Through micro-environmental study, highest log P value was observed for linagliptin (1.07). Lowest binding energy was also observed for linagliptin with DPP-4 in the binding plot. We also identified the number of H-bonds and residues involved in the hydrophobic interactions between the DPP-4 and the anti-diabetic drugs. During interaction, two H-bonds and nine residues, two H-bonds and eleven residues as well as four H-bonds and nine residues were found between the saxagliptin, linagliptin as well as vildagliptin cases and DPP-4, respectively. Our in silico data obtained for drug-target interactions and micro-environmental signature demonstrates linagliptin as the most stable interacting drug among the tested anti-diabetic medicines.

Cholinesterase Inhibitors and Hospitalization for Bradycardia: A Population-Based Study

PubMed Central

Park-Wyllie, Laura Y.; Mamdani, Muhammad M.; Li, Ping; Gill, Sudeep S.; Laupacis, Andreas; Juurlink, David N.

2009-01-01

Background Cholinesterase inhibitors are commonly used to treat dementia. These drugs enhance the effects of acetylcholine, and reports suggest they may precipitate bradycardia in some patients. We aimed to examine the association between use of cholinesterase inhibitors and hospitalization for bradycardia. Methods and Findings We examined the health care records of more than 1.4 million older adults using a case-time-control design, allowing each individual to serve as his or her own control. Case patients were residents of Ontario, Canada, aged 67 y or older hospitalized for bradycardia between January 1, 2003 and March 31, 2008. Control patients (3∶1) were not hospitalized for bradycardia, and were matched to the corresponding case on age, sex, and a disease risk index. All patients had received cholinesterase inhibitor therapy in the 9 mo preceding the index hospitalization. We identified 1,009 community-dwelling older persons hospitalized for bradycardia within 9 mo of using a cholinesterase inhibitor. Of these, 161 cases informed the matched analysis of discordant pairs. Of these, 17 (11%) required a pacemaker during hospitalization, and six (4%) died prior to discharge. After adjusting for temporal changes in drug utilization, hospitalization for bradycardia was associated with recent initiation of a cholinesterase inhibitor (adjusted odds ratio [OR] 2.13, 95% confidence interval [CI] 1.29–3.51). The risk was similar among individuals with pre-existing cardiac disease (adjusted OR 2.25, 95% CI 1.18–4.28) and those receiving negative chronotropic drugs (adjusted OR 2.34, 95% CI 1.16–4.71). We found no such association when we replicated the analysis using proton pump inhibitors as a neutral exposure. Despite hospitalization for bradycardia, more than half of the patients (78 of 138 cases [57%]) who survived to discharge subsequently resumed cholinesterase inhibitor therapy. Conclusions Among older patients, initiation of cholinesterase inhibitor therapy was associated with a more than doubling of the risk of hospitalization for bradycardia. Resumption of therapy following discharge was common, suggesting that the cardiovascular toxicity of cholinesterase inhibitors is underappreciated by clinicians. Please see later in the article for the Editors' Summary PMID:19787032

Antiinfective therapy with a small molecule inhibitor of Staphylococcus aureus sortase.

PubMed

Zhang, Jie; Liu, Hongchuan; Zhu, Kongkai; Gong, Shouzhe; Dramsi, Shaynoor; Wang, Ya-Ting; Li, Jiafei; Chen, Feifei; Zhang, Ruihan; Zhou, Lu; Lan, Lefu; Jiang, Hualiang; Schneewind, Olaf; Luo, Cheng; Yang, Cai-Guang

2014-09-16

Methicillin-resistant Staphylococcus aureus (MRSA) is the most frequent cause of hospital-acquired infection, which manifests as surgical site infections, bacteremia, and sepsis. Due to drug-resistance, prophylaxis of MRSA infection with antibiotics frequently fails or incites nosocomial diseases such as Clostridium difficile infection. Sortase A is a transpeptidase that anchors surface proteins in the envelope of S. aureus, and sortase mutants are unable to cause bacteremia or sepsis in mice. Here we used virtual screening and optimization of inhibitor structure to identify 3-(4-pyridinyl)-6-(2-sodiumsulfonatephenyl)[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole and related compounds, which block sortase activity in vitro and in vivo. Sortase inhibitors do not affect in vitro staphylococcal growth yet protect mice against lethal S. aureus bacteremia. Thus, sortase inhibitors may be useful as antiinfective therapy to prevent hospital-acquired S. aureus infection in high-risk patients without the side effects of antibiotics.

Exposure to antiretroviral therapy and risk of cancer in HIV-infected persons.

PubMed

Chao, Chun; Leyden, Wendy A; Xu, Lanfang; Horberg, Michael A; Klein, Daniel; Towner, William J; Quesenberry, Charles P; Abrams, Donald I; Silverberg, Michael J

2012-11-13

The incidence of certain non-AIDS-defining cancers (NADCs) in HIV patients has been reported to have increased in the combination antiretroviral therapy (ART) era. Studies are needed to directly evaluate the effect of ART use on cancer risk. We followed 12 872 HIV-infected Kaiser Permanente members whose complete ART history was known for incident cancers between 1996 and 2008. Cancers, identified from Surveillance, Epidemiology, and End Results (SEER)-based cancer registries, were grouped as ADCs, infection-related NADCs, or infection-unrelated NADCs. We also evaluated the most common individual cancer types. Rate ratios for ART use (yes/no) and cumulative duration of any ART, protease inhibitor, and nonnucleotide reverse transcriptase inhibitor (NNRTI) therapy were obtained from Poisson models adjusting for demographics, pretreatment or recent CD4 cell count and HIV RNA levels, years known HIV-infected, prior antiretroviral use, HIV risk, smoking, alcohol/drug abuse, overweight/obesity, and calendar year. The cohort experienced 32 368 person-years of ART, 21 249 person-years of protease inhibitor therapy, and 15 643 person-years of NNRTI therapy. The mean follow-up duration was 4.5 years. ADC rates decrease with increased duration of ART use [rate ratio per year = 0.61 (95% confidence interval 0.56-0.66)]; the effect was similar by therapy class. ART, protease inhibitor, or NNRTI therapy duration was not associated with infection-related or infection-unrelated NADC [rate ratio per year ART = 1.00 (0.91-1.11) and 0.96 (0.90-1.01), respectively], except a higher anal cancer risk with longer protease inhibitor therapy [rate ratio per year = 1.16 (1.02-1.31)]. No therapy class-specific effect was found for ADC. ART exposure was generally not associated with NADC risk, except for long-term use of protease inhibitor, which might be associated with increased anal cancer risk.

Dual kinase-bromodomain inhibitors for rationally designed polypharmacology

PubMed Central

Ciceri, Pietro; Müller, Susanne; O’Mahony, Alison; Fedorov, Oleg; Filippakopoulos, Panagis; Hunt, Jeremy P.; Lasater, Elisabeth A.; Pallares, Gabriel; Picaud, Sarah; Wells, Christopher; Martin, Sarah; Wodicka, Lisa M.; Shah, Neil P.; Treiber, Daniel K.; Knapp, Stefan

2014-01-01

Concomitant inhibition of multiple cancer-driving kinases is an established strategy to improve the durability of clinical responses to targeted therapies. The difficulty of discovering kinase inhibitors with an appropriate multi-target profile has, however, necessitated the application of combination therapies, which can pose significant clinical development challenges. Epigenetic reader domains of the bromodomain family have recently emerged as novel targets for cancer therapy. Here we report that several clinical kinase inhibitors also inhibit bromodomains with therapeutically relevant potencies and are best classified as dual kinase/bromodomain inhibitors. Nanomolar activity on BRD4 by BI-2536 and TG-101348, clinical PLK1 and JAK2/FLT3 kinase inhibitors, respectively, is particularly noteworthy as these combinations of activities on independent oncogenic pathways exemplify a novel strategy for rational single agent polypharmacological targeting. Furthermore, structure-activity relationships and co-crystal structures identify design features that enable a general platform for the rational design of dual kinase/bromodomain inhibitors. PMID:24584101

Purification, identification and molecular mechanism of two dipeptidyl peptidase IV (DPP-IV) inhibitory peptides from Antarctic krill (Euphausia superba) protein hydrolysate.

PubMed

Ji, Wei; Zhang, Chaohua; Ji, Hongwu

2017-10-01

Dipeptidyl peptidase IV (DPP-IV) played an important role in blood glucose regulation. Inhibition of DPP-IV may improve glycemic control in diabetics by preventing the rapid breakdown of incretin hormones and prolonging their physiological action. In this study, Antarctic krill (Euphausia superba) protein was hydrolyzed using animal proteolytic enzymes. The hydrolysate was purified sequentially by ultrafiltration, gel filtration chromatography and reversed phase high-performance liquid chromatography (RP-HPLC). DPP-IV inhibitory activity of the fractions achieved from Antarctic krill protein was determined by DPP-IV screening reagent kit. Two purified peptides were identified by Xevo G2-XS QTof mass spectrometer (QTOF-MS). One peptide purified was Ala-Pro (AP) with IC 50 values of 0.0530mg/mL, the other Ile-Pro-Ala (IPA) with IC 50 values of 0.0370mg/mL. They both exhibited strong DPP-IV inhibitory activity. The molecular docking analysis revealed that DPP-IV inhibition by AP and IPA was mainly due to formation of a strong interaction surface force with the 91-96 and 101-105 amino acids of the DPP-IV. Our results suggested that the protein hydrolysate from Antarctic krill can be considered as a promising natural source of DPP-IV inhibitory peptides in the management of diabetes. Copyright © 2017 Elsevier B.V. All rights reserved.

Implication of LRRC4C and DPP6 in neurodevelopmental disorders

PubMed Central

Maussion, Gilles; Cruceanu, Cristiana; Rosenfeld, Jill A.; Bell, Scott C.; Jollant, Fabrice; Szatkiewicz, Jin; Collins, Ryan L.; Hanscom, Carrie; Kolobova, Ilaria; de Champfleur, Nicolas Menjot; Blumenthal, Ian; Chiang, Colby; Ota, Vanessa; Hultman, Christina; O’Dushlaine, Colm; McCarroll, Steve; Alda, Martin; Jacquemont, Sebastien; Ordulu, Zehra; Marshall, Christian R.; Carter, Melissa T.; Shaffer, Lisa G.; Sklar, Pamela; Girirajan, Santhosh; Morton, Cynthia C.; Gusella, James F.; Turecki, Gustavo; Stavropoulos, D. J.; Sullivan, Patrick F.; Scherer, Stephen W.; Talkowski, Michael E.; Ernst, Carl

2018-01-01

We performed whole-genome sequencing on an individual from a family with variable psychiatric phenotypes that had a sensory processing disorder, apraxia, and autism. The proband harbored a maternally inherited balanced translocation (46,XY,t(11;14)(p12;p12)mat) that disrupted LRRC4C, a member of the highly specialized netrin G family of axon guidance molecules. The proband also inherited a paternally derived chromosomal inversion that disrupted DPP6, a potassium channel interacting protein. Copy Number (CN) analysis in 14,077 cases with neurodevelopmental disorders and 8,960 control subjects revealed that 60% of cases with exonic deletions in LRRC4C had a second clinically recognizable syndrome associated with variable clinical phenotypes, including 16p11.2, 1q44, and 2q33.1 CN syndromes, suggesting LRRC4C deletion variants may be modifiers of neurodevelopmental disorders. In vitro, functional assessments modeling patient deletions in LRRC4C suggest a negative regulatory role of these exons found in the untranslated region of LRRC4C, which has a single, terminal coding exon. These data suggest that the proband’s autism may be due to the inheritance of disruptions in both DPP6 and LRRC4C, and may highlight the importance of the netrin G family and potassium channel interacting molecules in neurodevelopmental disorders. PMID:27759917

30 CFR 550.266 - After receiving the DPP or DOCD, what will BOEM do?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 2 2012-07-01 2012-07-01 false After receiving the DPP or DOCD, what will BOEM do? 550.266 Section 550.266 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE... Review and Decision Process for the Dpp Or Docd § 550.266 After receiving the DPP or DOCD, what will BOEM...

30 CFR 250.266 - After receiving the DPP or DOCD, what will MMS do?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false After receiving the DPP or DOCD, what will MMS do? 250.266 Section 250.266 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR... Decision Process for the Dpp Or Docd § 250.266 After receiving the DPP or DOCD, what will MMS do? (a...

30 CFR 550.266 - After receiving the DPP or DOCD, what will BOEM do?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 2 2013-07-01 2013-07-01 false After receiving the DPP or DOCD, what will BOEM do? 550.266 Section 550.266 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE... Review and Decision Process for the Dpp Or Docd § 550.266 After receiving the DPP or DOCD, what will BOEM...

30 CFR 550.266 - After receiving the DPP or DOCD, what will BOEM do?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 2 2014-07-01 2014-07-01 false After receiving the DPP or DOCD, what will BOEM do? 550.266 Section 550.266 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE... Review and Decision Process for the Dpp Or Docd § 550.266 After receiving the DPP or DOCD, what will BOEM...

Quinoline-Flanked Diketopyrrolopyrrole Copolymers Breaking through Electron Mobility over 6 cm2 V-1 s-1 in Flexible Thin Film Devices.

PubMed

Ni, Zhenjie; Dong, Huanli; Wang, Hanlin; Ding, Shang; Zou, Ye; Zhao, Qiang; Zhen, Yonggang; Liu, Feng; Jiang, Lang; Hu, Wenping

2018-03-01

Herein, the design and synthesis of novel π-extended quinoline-flanked diketopyrrolopyrrole (DPP) [abbreviated as QDPP] motifs and corresponding copolymers named PQDPP-T and PQDPP-2FT for high performing n-type organic field-effect transistors (OFETs) in flexible organic thin film devices are reported. Serving as DPP-flankers in backbones, quinoline is found to effectively tune copolymer optoelectric properties. Compared with TDPP and pyridine-flanked DPP (PyDPP) analogs, widened bandgaps and strengthened electron deficiency are achieved. Moreover, both hole and electron mobility are improved two orders of magnitude compared to those of PyDPP analogs (PPyDPP-T and PPyDPP-2FT). Notably, featuring an all-acceptor-incorporated backbone, PQDPP-2FT exhibits electron mobility of 6.04 cm 2 V -1 s -1 , among the highest value in OFETs fabricated on flexible substrates to date. Moreover, due to the widened bandgap and strengthened electron deficiency of PQDPP, n-channel on/off ratio over 10 5 with suppressed hole transport is first realized in the ambipolar DPP-based copolymers. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inwardly rectifying potassium channels influence Drosophila wing morphogenesis by regulating Dpp release.

PubMed

Dahal, Giri Raj; Pradhan, Sarala Joshi; Bates, Emily Anne

2017-08-01

Loss of embryonic ion channel function leads to morphological defects, but the underlying reason for these defects remains elusive. Here, we show that inwardly rectifying potassium (Irk) channels regulate release of the Drosophila bone morphogenetic protein Dpp in the developing fly wing and that this is necessary for developmental signaling. Inhibition of Irk channels decreases the incidence of distinct Dpp-GFP release events above baseline fluorescence while leading to a broader distribution of Dpp-GFP. Work by others in different cell types has shown that Irk channels regulate peptide release by modulating membrane potential and calcium levels. We found calcium transients in the developing wing, and inhibition of Irk channels reduces the duration and amplitude of calcium transients. Depolarization with high extracellular potassium evokes Dpp release. Taken together, our data implicate Irk channels as a requirement for regulated release of Dpp, highlighting the importance of the temporal pattern of Dpp presentation for morphogenesis of the wing. © 2017. Published by The Company of Biologists Ltd.

Fungal Mimicry of a Mammalian Aminopeptidase Disables Innate Immunity and Promotes Pathogenicity.

PubMed

Sterkel, Alana K; Lorenzini, Jenna L; Fites, J Scott; Subramanian Vignesh, Kavitha; Sullivan, Thomas D; Wuthrich, Marcel; Brandhorst, Tristan; Hernandez-Santos, Nydiaris; Deepe, George S; Klein, Bruce S

2016-03-09

Systemic fungal infections trigger marked immune-regulatory disturbances, but the mechanisms are poorly understood. We report that the pathogenic yeast of Blastomyces dermatitidis elaborates dipeptidyl-peptidase IVA (DppIVA), a close mimic of the mammalian ectopeptidase CD26, which modulates critical aspects of hematopoiesis. We show that, like the mammalian enzyme, fungal DppIVA cleaved C-C chemokines and GM-CSF. Yeast producing DppIVA crippled the recruitment and differentiation of monocytes and prevented phagocyte activation and ROS production. Silencing fungal DppIVA gene expression curtailed virulence and restored recruitment of CCR2(+) monocytes, generation of TipDC, and phagocyte killing of yeast. Pharmacological blockade of DppIVA restored leukocyte effector functions and stemmed infection, while addition of recombinant DppIVA to gene-silenced yeast enabled them to evade leukocyte defense. Thus, fungal DppIVA mediates immune-regulatory disturbances that underlie invasive fungal disease. These findings reveal a form of molecular piracy by a broadly conserved aminopeptidase during disease pathogenesis. Copyright © 2016 Elsevier Inc. All rights reserved.

Multicenter Evaluation of the Tolerability of Combined Treatment With PD-1 and CTLA-4 Immune Checkpoint Inhibitors and Palliative Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bang, Andrew; Division of Radiation Oncology, University of Ottawa, Ottawa, Ontario; Wilhite, Tyler J.

Purpose: To analyze immune-related adverse events (ir-AEs) in patients treated with radiation and immune checkpoint blockade. Methods and Materials: We retrospectively reviewed records from patients with metastatic non-small cell lung cancer, melanoma, or renal cell cancer who received at least 1 cycle of a CTLA-4 or PD-1 inhibitor and radiation. Immune-related adverse events, defined using Common Terminology Criteria for Adverse Events version 4.0, were tabulated in relation to treatment variables, and associations with sequencing and timing were assessed. Results: We identified 133 patients, of whom 28 received a CTLA-4 inhibitor alone, 88 received a PD-1 inhibitor alone, and 17 received bothmore » classes of inhibitors either sequentially (n=13) or concurrently (n=4). Fifty-six patients received radiation within 14 days of an immune checkpoint inhibitor. Forty-six patients experienced at least 1 ir-AE (34.6%). Patients receiving both CTLA-4 and PD-1 inhibitors experienced more any-grade ir-AEs as compared with either individually (71% vs 29%, P=.0008). Any-grade ir-AEs occurred in 39% of patients in whom radiation was administered within 14 days of immunotherapy, compared with 23% of other patients (P=.06) and more often in patients who received higher equivalent dose in 2-Gy fractions (EQD2) EQD2 (P=.01). However, most toxicities were mild. There were no associations between site irradiated and specific ir-AEs. Conclusions: Our data suggest the combination of focal palliative radiation and CTLA-4 and/or PD-1 inhibitors is well tolerated, with manageable ir-AEs that did not seem to be associated with the particular site irradiated. Although conclusions are limited by the heterogeneity of patients and treatments, and future confirmatory studies are needed, this information can help guide clinical practice for patients receiving immune checkpoint therapy who require palliative radiation therapy.« less

A Randomized Controlled Trial of Vildagliptin Versus Alogliptin: Effective Switch From Sitagliptin in Patients With Type 2 Diabetes.

PubMed

Shigematsu, Erina; Yamakawa, Tadashi; Oba, Mari S; Suzuki, Jun; Nagakura, Jo; Kadonosono, Kazuaki; Terauchi, Yasuo

2017-07-01

We investigated the effects of vildagliptin or alogliptin on blood glucose and hemoglobin A1c (HbA1c) in patients with type 2 diabetes inadequately controlled by sitagliptin. In a single-center open-label trial, 35 patients with inadequate glycemic control on sitagliptin therapy (50 mg once daily) were randomly switched to treatment with vildagliptin (50 mg twice daily) or alogliptin (25 mg once daily). After 12 weeks, patients who failed to achieve the target HbA1c level of < 7.0% with vildagliptin or alogliptin treatment were switched to high-dose sitagliptin (100 mg once daily) and the effect on glycemic control was assessed. Vildagliptin did not significantly alter the mean plasma glucose level (175.5 ± 54.4 mg/dL vs. 179.1 ± 73.4 mg/dL) or HbA1c (8.01% vs. 8.02%) after 12 weeks. With alogliptin, mean plasma glucose increased from 175.4 ± 50.9 mg/dL to 195.3 ± 55.0 mg/dL after 12 weeks and HbA1c increased significantly from 8.0% to 8.3% (P < 0.05). At 12 weeks after switching from vildagliptin to high-dose sitagliptin (100 mg daily), HbA1c was increased to 8.3%, but it was significantly (P < 0.05) reduced to the baseline level of 8.0% after switching from alogliptin. The reduction of HbA1c was significantly greater in the vildagliptin group than the alogliptin group (P = 0.008), but the response rate (achieving the target HbA1c < 7.0%) did not differ significantly between the two groups. The glucose-lowering effects of these three dipeptidyl peptidase-4 (DPP-4) inhibitors (vildagliptin, alogliptin, and sitagliptin) were different, and the effects of vildagliptin and sitagliptin were stronger than that of alogliptin.

Switching from subcutaneous insulin injection to oral vildagliptin administration in hemodialysis patients with type 2 diabetes: a pilot study.

PubMed

Yoshida, Naoshi; Babazono, Tetsuya; Hanai, Ko; Uchigata, Yasuko

2016-08-01

We conducted this pilot study to examine efficacy and safety of switching from subcutaneous injection of insulin to oral administration of a DPP-4 inhibitor, vildagliptin, in type 2 diabetic patients undergoing hemodialysis. Consecutive type 2 diabetic patients on hemodialysis who were switched from insulin to vildagliptin between August 2010 and April 2011 were extracted from the hospital database. In patients whose post-switch increase in glycated albumin (GA) levels was <1.5 % without resuming insulin at least 24 weeks, the switch was defined as efficacious. In patients who resumed insulin therapy due to worsening of glycemic control or in patients whose GA levels increased by 1.5 % or more, the switch was considered inefficacious. To predict patients in whom switch to vildagliptin proved efficacious, receiver-operating characteristic (ROC) analysis and logistic regression analysis were performed. A total of 20 patients were extracted; insulin dose was 12 ± 4 units/day; levels of GA and HbA1c was 21.0 ± 3.7 % and 6.5 ± 0.6 %, respectively. Among them, 11 patients were efficaciously switched to vildagliptin. ROC analysis and logistic analysis showed that patients with a shorter duration of diabetes, as well as lower levels of GA and HbA1c, appeared to have a higher likelihood of successful treatment switches. None of the patients developed hypoglycemic symptoms, ketoacidosis, or serious adverse events. In conclusion, efficacious change from insulin to vildagliptin was possible in approximately a half of type 2 diabetic dialysis patients. Long-term follow-up studies including large number of patients are needed to confirm these results.

One year of sitagliptin treatment protects against islet amyloid-associated β-cell loss and does not induce pancreatitis or pancreatic neoplasia in mice

PubMed Central

Aston-Mourney, Kathryn; Subramanian, Shoba L.; Zraika, Sakeneh; Samarasekera, Thanya; Meier, Daniel T.; Goldstein, Lynn C.

2013-01-01

The dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin is an attractive therapy for diabetes, as it increases insulin release and may preserve β-cell mass. However, sitagliptin also increases β-cell release of human islet amyloid polypeptide (hIAPP), the peptide component of islet amyloid, which is cosecreted with insulin. Thus, sitagliptin treatment may promote islet amyloid formation and its associated β-cell toxicity. Conversely, metformin treatment decreases islet amyloid formation by decreasing β-cell secretory demand and could therefore offset sitagliptin's potential proamyloidogenic effects. Sitagliptin treatment has also been reported to be detrimental to the exocrine pancreas. We investigated whether long-term sitagliptin treatment, alone or with metformin, increased islet amyloid deposition and β-cell toxicity and induced pancreatic ductal proliferation, pancreatitis, and/or pancreatic metaplasia/neoplasia. hIAPP transgenic and nontransgenic littermates were followed for 1 yr on no treatment, sitagliptin, metformin, or the combination. Islet amyloid deposition, β-cell mass, insulin release, and measures of exocrine pancreas pathology were determined. Relative to untreated mice, sitagliptin treatment did not increase amyloid deposition, despite increasing hIAPP release, and prevented amyloid-induced β-cell loss. Metformin treatment alone or with sitagliptin decreased islet amyloid deposition to a similar extent vs untreated mice. Ductal proliferation was not altered among treatment groups, and no evidence of pancreatitis, ductal metaplasia, or neoplasia were observed. Therefore, long-term sitagliptin treatment stimulates β-cell secretion without increasing amyloid formation and protects against amyloid-induced β-cell loss. This suggests a novel effect of sitagliptin to protect the β-cell in type 2 diabetes that appears to occur without adverse effects on the exocrine pancreas. PMID:23736544

Diabetes Prevention Program (DPP)

MedlinePlus

... mass index of 35 or higher. DPP Study Design The DPP was a randomized, controlled clinical trial ... by several earlier small-scale studies. DPPOS Study Design The DPPOS follow-up study started in 2002. ...

Translating the Diabetes Prevention Program for Northern Plains Indian Youth Through Community-Based Participatory Research Methods

PubMed Central

Brown, Blakely D.; Harris, Kari Jo; Harris, Jeri Lyn; Parker, Martin; Ricci, Christiana; Noonan, Curtis

2012-01-01

Purpose The purpose of this study was to use a community-based participatory research (CBPR) approach to translate the original Diabetes Prevention Program (DPP) to be age and culturally specific for American Indian (AI) youth. Methods Tribally enrolled members on 2 Montana Indian reservations conducted focus groups and interviews to discuss community members’ perspectives of factors that encouraged or were barriers to healthy diet and exercise behaviors in AI youth. In total, 31 community members, aged 10 to 68 years old, participated in 4 focus groups and 14 individual interviews. Participants were self-identified as elder, cultural expert, tribal health worker, educator, parent/guardian, youth, or school food service worker. Researchers analyzed transcripts based on inductive methods of grounded theory. Results Data analysis revealed translating the DPP to youth was contingent on the lessons incorporating cultural strategies for healthy behaviors in youth such as berry picking, gardening, horseback riding, and dancing; improving knowledge and access to healthy foods and physical activity for youth and their parents; having interactive, hands-on learning activities for healthy lifestyles in the DPP lessons; using a group format and tribal members to deliver the DPP lessons; and having tribal elders talk to youth about the importance of adopting healthy behaviors when they are young. Conclusions A CBPR approach engaged community members to identify strategies inherent in their culture, tradition, and environment that could effectively translate the DPP to Montana Indian youth living in rural reservation communities. PMID:20944056

Design of a comparative effectiveness randomized controlled trial testing a faith-based Diabetes Prevention Program (WORD DPP) vs. a Pacific culturally adapted Diabetes Prevention Program (PILI DPP) for Marshallese in the United States.

PubMed

McElfish, Pearl Anna; Long, Christopher R; Kaholokula, Joseph Keawe'aimoku; Aitaoto, Nia; Bursac, Zoran; Capelle, Lucy; Laelan, Melisa; Bing, Williamina Ioanna; Riklon, Sheldon; Rowland, Brett; Ayers, Britni L; Wilmoth, Ralph O; Langston, Krista N; Schootman, Mario; Selig, James P; Yeary, Karen Hye-Cheon Kim

2018-05-01

Pacific Islander populations, including Marshallese, face a disproportionately high burden of health disparities relative to the general population. A community-based participatory research (CBPR) approach was utilized to engage Marshallese participants in a comparative effectiveness trial testing 2 Diabetes Prevention Program (DPP) interventions designed to reduce participant's weight, lower HbA1c, encourage healthy eating, and increase physical activity. To compare the effectiveness of the faith-based (WORD) DPP to the culturally adapted (Pacific Culturally Adapted Diabetes Prevention Program [PILI]) DPP, a clustered randomized controlled trial (RCT) with 384 Marshallese participants will be implemented in 32 churches located in Arkansas, Kansas, Missouri, and Oklahoma. Churches will be randomly assigned to WORD DPP arm or to PILI DPP arm. WORD DPP focuses on connecting faith and health to attain a healthy weight, eat healthy, and be more physically active. In contrast, PILI DPP is a family and community focused DPP curriculum specifically adapted for implementation in Pacific Islander communities. PILI focuses on engaging social support networks to maintain a healthy weight, eat healthy, and be more physically active. All participants are assessed at baseline, immediate post intervention, and 12 months post intervention. Both interventions aim to cause weight loss through improving physical activity and healthy eating, with the goal of preventing the development of T2D. The clustered RCT will determine which intervention is most effective with the Marshallese population. The utilization of a CBPR approach that involves local stakeholders and engages faith-based institutions in Marshallese communities will increase the potential for success and sustainability. This study is registered at clinicaltrials.gov (NCT03270436).

Design of a comparative effectiveness randomized controlled trial testing a faith-based Diabetes Prevention Program (WORD DPP) vs. a Pacific culturally adapted Diabetes Prevention Program (PILI DPP) for Marshallese in the United States

PubMed Central

McElfish, Pearl Anna; Long, Christopher R.; Kaholokula, Joseph Keawe‘aimoku; Aitaoto, Nia; Bursac, Zoran; Capelle, Lucy; Laelan, Melisa; Bing, Williamina Ioanna; Riklon, Sheldon; Rowland, Brett; Ayers, Britni L.; Wilmoth, Ralph O.; Langston, Krista N.; Schootman, Mario; Selig, James P.; Yeary, Karen Hye-cheon Kim

2018-01-01

Abstract Background: Pacific Islander populations, including Marshallese, face a disproportionately high burden of health disparities relative to the general population. Objectives: A community-based participatory research (CBPR) approach was utilized to engage Marshallese participants in a comparative effectiveness trial testing 2 Diabetes Prevention Program (DPP) interventions designed to reduce participant's weight, lower HbA1c, encourage healthy eating, and increase physical activity. Design: To compare the effectiveness of the faith-based (WORD) DPP to the culturally adapted (Pacific Culturally Adapted Diabetes Prevention Program [PILI]) DPP, a clustered randomized controlled trial (RCT) with 384 Marshallese participants will be implemented in 32 churches located in Arkansas, Kansas, Missouri, and Oklahoma. Churches will be randomly assigned to WORD DPP arm or to PILI DPP arm. Methods: WORD DPP focuses on connecting faith and health to attain a healthy weight, eat healthy, and be more physically active. In contrast, PILI DPP is a family and community focused DPP curriculum specifically adapted for implementation in Pacific Islander communities. PILI focuses on engaging social support networks to maintain a healthy weight, eat healthy, and be more physically active. All participants are assessed at baseline, immediate post intervention, and 12 months post intervention. Summary: Both interventions aim to cause weight loss through improving physical activity and healthy eating, with the goal of preventing the development of T2D. The clustered RCT will determine which intervention is most effective with the Marshallese population. The utilization of a CBPR approach that involves local stakeholders and engages faith-based institutions in Marshallese communities will increase the potential for success and sustainability. This study is registered at clinicaltrials.gov (NCT03270436). PMID:29742712

Asp- and Glu-specific Novel Dipeptidyl Peptidase 11 of Porphyromonas gingivalis Ensures Utilization of Proteinaceous Energy Sources*

PubMed Central

Ohara-Nemoto, Yuko; Shimoyama, Yu; Kimura, Shigenobu; Kon, Asako; Haraga, Hiroshi; Ono, Toshio; Nemoto, Takayuki K.

2011-01-01

Porphyromonas gingivalis and Porphyromonas endodontalis, asaccharolytic black-pigmented anaerobes, are predominant pathogens of human chronic and periapical periodontitis, respectively. They incorporate di- and tripeptides from the environment as carbon and energy sources. In the present study we cloned a novel dipeptidyl peptidase (DPP) gene of P. endodontalis ATCC 35406, designated as DPP11. The DPP11 gene encoded 717 amino acids with a molecular mass of 81,090 Da and was present as a 75-kDa form with an N terminus of Asp22. A homology search revealed the presence of a P. gingivalis orthologue, PGN0607, that has been categorized as an isoform of authentic DPP7. P. gingivalis DPP11 was exclusively cell-associated as a truncated 60-kDa form, and the gene ablation retarded cell growth. DPP11 specifically removed dipeptides from oligopeptides with the penultimate N-terminal Asp and Glu and has a P2-position preference to hydrophobic residues. Optimum pH was 7.0, and the kcat/Km value was higher for Asp than Glu. Those activities were lost by substitution of Ser652 in P. endodontalis and Ser655 in P. gingivalis DPP11 to Ala, and they were consistently decreased with increasing NaCl concentration. Arg670 is a unique amino acid completely conserved in all DPP11 members distributed in the genera Porphyromonas, Bacteroides, and Parabacteroides, whereas this residue is converted to Gly in all authentic DPP7 members. Substitution analysis suggested that Arg670 interacts with an acidic residue of the substrate. Considered to preferentially utilize acidic amino acids, DPP11 ensures efficient degradation of oligopeptide substrates in these Gram-negative anaerobic rods. PMID:21896480