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Sample records for affect drug metabolism

  1. Drug metabolism in the skin.

    PubMed

    Baron, J M; Merk, H F

    2001-08-01

    The skin performs a wide range of active metabolic functions including xenobiotic metabolism involving metabolizing enzymes specific to the skin. In this review we focus on the role of drug metabolism: (i) in allergic reactions to substances of low molecular weight; (ii) in cutaneous vitamin A and D3 metabolism and its modulation; (iii) in the interaction of transport and metabolic enzymes in skin cells; and (iv) on novel tools for the measurement of drug metabolism in various compartments of the human skin.

  2. Drug-Induced Metabolic Acidosis.

    PubMed

    Pham, Amy Quynh Trang; Xu, Li Hao Richie; Moe, Orson W

    2015-01-01

    Metabolic acidosis could emerge from diseases disrupting acid-base equilibrium or from drugs that induce similar derangements. Occurrences are usually accompanied by comorbid conditions of drug-induced metabolic acidosis, and clinical outcomes may range from mild to fatal. It is imperative that clinicians not only are fully aware of the list of drugs that may lead to metabolic acidosis but also understand the underlying pathogenic mechanisms. In this review, we categorized drug-induced metabolic acidosis in terms of pathophysiological mechanisms, as well as individual drugs' characteristics. PMID:26918138

  3. [Metabolism of drugs. I. Basic metabolic reactions].

    PubMed

    Dyderski, Stanisław; Grzymisławski, Marian

    2005-04-01

    Pharmacologic effect of the drug results from its metabolism to metabolites showing decreased lipophilic properties and increased solubility in water. Transformations leading to inactivation of the drug are usually conducted by microsomal enzymes combined with cytochrome P-450. Main types of the metabolic reactions involved in the metabolism of exogenous substances are: oxidative reactions, hydrolysis and coupling reactions (often called second phase reactions). Estimation of the appearance of metabolites containing reactive groups (amino- or hydroxyl) should take into consideration the factor influencing the coupling reactions with glucuronic acid, sulphides, but also N-acetylation and methylation, coupling with glutathione or amino acids (mainly glycine and glutamine). Liver plays basic role in the metabolism of the drugs, but this metabolic activity appears also in the alimentary canal, where under influence of hydrochloric acid in stomach and intestine enzymes some xenobiotics are degraded. A special role is also played by intestine microflora.

  4. Drug-Induced Metabolic Acidosis

    PubMed Central

    Pham, Amy Quynh Trang; Xu, Li Hao Richie; Moe, Orson W.

    2015-01-01

    Metabolic acidosis could emerge from diseases disrupting acid-base equilibrium or from drugs that induce similar derangements. Occurrences are usually accompanied by comorbid conditions of drug-induced metabolic acidosis, and clinical outcomes may range from mild to fatal. It is imperative that clinicians not only are fully aware of the list of drugs that may lead to metabolic acidosis but also understand the underlying pathogenic mechanisms. In this review, we categorized drug-induced metabolic acidosis in terms of pathophysiological mechanisms, as well as individual drugs’ characteristics. PMID:26918138

  5. Altered drug metabolism during pregnancy: Hormonal regulation of drug-metabolizing enzymes

    PubMed Central

    Jeong, Hyunyoung

    2013-01-01

    Importance of the field Medication use during pregnancy is prevalent, but pharmacokinetic information of most drugs used during pregnancy is lacking in spite of known effects of pregnancy on drug disposition. Accurate pharmacokinetic information is essential for optimal drug therapy in mother and fetus. Thus, understanding how pregnancy influences drug disposition is important for better prediction of pharmacokinetic changes of drugs in pregnant women. Areas covered in this review Pregnancy is known to affect hepatic drug metabolism, but the underlying mechanisms remain unknown. Physiological changes accompanying pregnancy are likely responsible for the reported alteration in drug metabolism during pregnancy. These include elevated concentrations of various hormones such as estrogen, progesterone, placental growth hormones and prolactin. This review covers how these hormones influence expression of drug-metabolizing enzymes, thus potentially responsible for altered drug metabolism during pregnancy. What the reader will gain The reader will gain a greater understanding of the altered drug metabolism in pregnant women and the regulatory effects of pregnancy hormones on expression of drug-metabolizing enzymes. Take home message In-depth studies in hormonal regulatory mechanisms as well as confirmatory studies in pregnant women are warranted for systematic understanding and prediction of the changes in hepatic drug metabolism during pregnancy. PMID:20367533

  6. "Target-Site" Drug Metabolism and Transport.

    PubMed

    Foti, Robert S; Tyndale, Rachel F; Garcia, Kristine L P; Sweet, Douglas H; Nagar, Swati; Sharan, Satish; Rock, Dan A

    2015-08-01

    The recent symposium on "Target-Site" Drug Metabolism and Transport that was sponsored by the American Society for Pharmacology and Experimental Therapeutics at the 2014 Experimental Biology meeting in San Diego is summarized in this report. Emerging evidence has demonstrated that drug-metabolizing enzyme and transporter activity at the site of therapeutic action can affect the efficacy, safety, and metabolic properties of a given drug, with potential outcomes including altered dosing regimens, stricter exclusion criteria, or even the failure of a new chemical entity in clinical trials. Drug metabolism within the brain, for example, can contribute to metabolic activation of therapeutic drugs such as codeine as well as the elimination of potential neurotoxins in the brain. Similarly, the activity of oxidative and conjugative drug-metabolizing enzymes in the lung can have an effect on the efficacy of compounds such as resveratrol. In addition to metabolism, the active transport of compounds into or away from the site of action can also influence the outcome of a given therapeutic regimen or disease progression. For example, organic anion transporter 3 is involved in the initiation of pancreatic β-cell dysfunction and may have a role in how uremic toxins enter pancreatic β-cells and ultimately contribute to the pathogenesis of gestational diabetes. Finally, it is likely that a combination of target-specific metabolism and cellular internalization may have a significant role in determining the pharmacokinetics and efficacy of antibody-drug conjugates, a finding which has resulted in the development of a host of new analytical methods that are now used for characterizing the metabolism and disposition of antibody-drug conjugates. Taken together, the research summarized herein can provide for an increased understanding of potential barriers to drug efficacy and allow for a more rational approach for developing safe and effective therapeutics.

  7. Changes of pathological and physiological indicators affecting drug metabolism in rats after acute exposure to high altitude

    PubMed Central

    LI, WENBIN; WANG, RONG; XIE, HUA; ZHANG, JUANHONG; JIA, ZHENGPING

    2015-01-01

    High altitude environments cause the human body to undergo a series of pathological, physiological and biochemical changes, which have a certain effect on drug pharmacokinetics. The objective of the present study was to observe changes in factors affecting pharmacokinetics in rats following acute exposure to high altitude and return to low altitude. A total of 21 male Wistar rats were randomly assigned to three groups. The rats in group A were maintained at low altitude in Shanghai, 55 m above sea level; those in group B were acutely exposed to high altitude in Maqu, Gansu, 4,010 m above sea level; and those in group C were acutely exposed to high altitude and then returned to low altitude. Blood was collected from the orbit for the analysis of significant biochemical indicators and from the abdominal aorta for blood gas analysis. Brain, lung and kidney tissues were removed to observe pathological changes. In group B, the pH, buffer base (BB), base excess (BE), total carbon dioxide content (ctCO2), oxygen saturation of arterial blood (sO2), oxygen tension of arterial blood (pO2), serum sodium (Na+) concentration, lactate dehydrogenase (LDH) activity and total protein (TP) level were significantly reduced, and the carbon dioxide tension of arterial blood (pCO2), serum chloride (Cl−) concentration, serum total bilirubin (TBIL) level and alkaline phosphatase (ALP) activity were significantly increased compared with those in group A (P<0.05). In group C, the pH, BB, BE, sO2, pO2, hemoglobin (Hb) level, serum Na+ concentration, LDH activity and TP level were significantly reduced, and the pCO2, serum Cl− concentration, alanine transaminase activity, TBIL and urea levels were significantly increased (P<0.05) compared with those in group A. The Hb and ALP levels in group C were significantly lower than those in group B (P<0.05); and the TP, TBIL and urea levels in group C were significantly higher than those in group B (P<0.05). Pathological observation revealed that

  8. Cancer Metabolism and Drug Resistance

    PubMed Central

    Rahman, Mahbuba; Hasan, Mohammad Rubayet

    2015-01-01

    Metabolic alterations, driven by genetic and epigenetic factors, have long been known to be associated with the etiology of cancer. Furthermore, accumulating evidence suggest that cancer metabolism is intimately linked to drug resistance, which is currently one of the most important challenges in cancer treatment. Altered metabolic pathways help cancer cells to proliferate at a rate higher than normal, adapt to nutrient limited conditions, and develop drug resistance phenotypes. Application of systems biology, boosted by recent advancement of novel high-throughput technologies to obtain cancer-associated, transcriptomic, proteomic and metabolomic data, is expected to make a significant contribution to our understanding of metabolic properties related to malignancy. Indeed, despite being at a very early stage, quantitative data obtained from the omics platforms and through applications of 13C metabolic flux analysis (MFA) in in vitro studies, researchers have already began to gain insight into the complex metabolic mechanisms of cancer, paving the way for selection of molecular targets for therapeutic interventions. In this review, we discuss some of the major findings associated with the metabolic pathways in cancer cells and also discuss new evidences and achievements on specific metabolic enzyme targets and target-directed small molecules that can potentially be used as anti-cancer drugs. PMID:26437434

  9. Curiosities in drug metabolism.

    PubMed

    Mitchell, Stephen C; Waring, Rosemary H; Smith, Robert L

    2014-07-01

    1. It is inevitable that during some xenobiotic biotransformation studies, a certain metabolite or degradation product arises of which the identity is uncertain, the route of formation is ambiguous, or it is just a plain mystery. 2. The following communication draws attention to three drugs reported in the literature, chlorphentermine, phenothiazine and aminopyrine, where after many years of investigation there still exists uncertainty over some of their metabolites. Noticeably, these three examples probably involve (potential) interaction of a nitrogen centre within the drug molecule. 3. It is hoped that the resurrection and assemblage of these data will offer interesting reading and that these examples may prove sufficiently intriguing to motivate further exploration and some resolution of these lingering concerns. PMID:24779638

  10. The evolution of drug metabolism.

    PubMed

    Nebert, D W; Dieter, M Z

    2000-09-01

    So-called 'drug-metabolizing enzyme' (DME) genes have existed on this planet for more than 2.5 billion years and would be more appropriately named 'effector-metabolizing enzymes'. Genes encoding DMEs have functioned in many fundamental processes in prokaryotes and, more recently, in countless critical life processes in plants and animals. DME genes exist in every eukaryotic cell and in most, if not all, prokaryotes. Over the past decade, it has become clear that each person has their own 'individual fingerprint' of unique alleles coding for DMEs. The underlying genetic predisposition of each patient reflects combinations of poor- and extensive-metabolizer phenotypes. If these enzymes cooperate in the same metabolic pathway for any given drug or environmental agent, such ecogenetic variability might be synergistic and could cause 30- to > 40-fold differences in activation or degradation. The end result can be large interindividual differences in risk of environmentally caused toxicity or cancer. Human DME gene polymorphisms often show high frequencies of variant alleles. Many factors contribute to persistence of these high frequencies, including a combination of selective pressures involving diet, climate and geography, as well as 'balanced polymorphisms' ('shared benefit' for the heterozygote). However, the extensive heterogeneity in the human genome currently being discovered suggests many more polymorphisms will occur not only in drug metabolism genes, but in all genes, and exhibiting large gene-by-gene variability.

  11. Nuclear Receptors in Drug Metabolism, Drug Response and Drug Interactions

    PubMed Central

    Prakash, Chandra; Zuniga, Baltazar; Song, Chung Seog; Jiang, Shoulei; Cropper, Jodie; Park, Sulgi; Chatterjee, Bandana

    2016-01-01

    Orally delivered small-molecule therapeutics are metabolized in the liver and intestine by phase I and phase II drug-metabolizing enzymes (DMEs), and transport proteins coordinate drug influx (phase 0) and drug/drug-metabolite efflux (phase III). Genes involved in drug metabolism and disposition are induced by xenobiotic-activated nuclear receptors (NRs), i.e. PXR (pregnane X receptor) and CAR (constitutive androstane receptor), and by the 1α, 25-dihydroxy vitamin D3-activated vitamin D receptor (VDR), due to transactivation of xenobiotic-response elements (XREs) present in phase 0-III genes. Additional NRs, like HNF4-α, FXR, LXR-α play important roles in drug metabolism in certain settings, such as in relation to cholesterol and bile acid metabolism. The phase I enzymes CYP3A4/A5, CYP2D6, CYP2B6, CYP2C9, CYP2C19, CYP1A2, CYP2C8, CYP2A6, CYP2J2, and CYP2E1 metabolize >90% of all prescription drugs, and phase II conjugation of hydrophilic functional groups (with/without phase I modification) facilitates drug clearance. The conjugation step is mediated by broad-specificity transferases like UGTs, SULTs, GSTs. This review delves into our current understanding of PXR/CAR/VDR-mediated regulation of DME and transporter expression, as well as effects of single nucleotide polymorphism (SNP) and epigenome (specified by promoter methylation, histone modification, microRNAs, long non coding RNAs) on the expression of PXR/CAR/VDR and phase 0-III mediators, and their impacts on variable drug response. Therapeutic agents that target epigenetic regulation and the molecular basis and consequences (overdosing, underdosing, or beneficial outcome) of drug-drug/drug-food/drug-herb interactions are also discussed. Precision medicine requires understanding of a drug’s impact on DME and transporter activity and their NR-regulated expression in order to achieve optimal drug efficacy without adverse drug reactions. In future drug screening, new tools such as humanized mouse models and

  12. Antihypertensive drugs and glucose metabolism

    PubMed Central

    Rizos, Christos V; Elisaf, Moses S

    2014-01-01

    Hypertension plays a major role in the development and progression of micro- and macrovascular disease. Moreover, increased blood pressure often coexists with additional cardiovascular risk factors such as insulin resistance. As a result the need for a comprehensive management of hypertensive patients is critical. However, the various antihypertensive drug categories have different effects on glucose metabolism. Indeed, angiotensin receptor blockers as well as angiotensin converting enzyme inhibitors have been associated with beneficial effects on glucose homeostasis. Calcium channel blockers (CCBs) have an overall neutral effect on glucose metabolism. However, some members of the CCBs class such as azelnidipine and manidipine have been shown to have advantageous effects on glucose homeostasis. On the other hand, diuretics and β-blockers have an overall disadvantageous effect on glucose metabolism. Of note, carvedilol as well as nebivolol seem to differentiate themselves from the rest of the β-blockers class, being more attractive options regarding their effect on glucose homeostasis. The adverse effects of some blood pressure lowering drugs on glucose metabolism may, to an extent, compromise their cardiovascular protective role. As a result the effects on glucose homeostasis of the various blood pressure lowering drugs should be taken into account when selecting an antihypertensive treatment, especially in patients which are at high risk for developing diabetes. PMID:25068013

  13. [Mechanisms of drug metabolism--implications for drug interaction].

    PubMed

    Sitkiewicz, D

    2000-09-01

    Most drugs undergo biotransformation before excretion by renal, biliary or other routes. The main purpose of metabolism is to make the drug, which is usually lipophilic, more water soluble. Metabolic reactions, depending upon the end product formed, can be classified as functionalisation (phase I) or conjugation (Phase II) reactions. Phase I metabolic reactions include oxidation, reduction and hydrolysis; while phase II processes are glucuronidation, sulfation, methylation, acetylation and mercapture formation. Cytochrome P-450 isozymes play a central role in metabolism of great majority of xenobiotics, as well as some endogenous substances. Many drugs can inhibit, induce and alter relative amounts of different P-450 enzymes; therefore, possibilities of drug-drug interactions exist in that one drug can influence biodisposition of another with potential clinical implications. One drug can inhibit metabolism of another, leading to excessive accumulation and toxicity. Alternatively, one drug can stimulate or induce metabolism of another drug resulting in subtherapeutic plasma levels of the later.

  14. In Vitro Drug Metabolism Using Liver Microsomes.

    PubMed

    Knights, Kathleen M; Stresser, David M; Miners, John O; Crespi, Charles L

    2016-01-01

    Knowledge of the metabolic stability of newly discovered drug candidates eliminated by metabolism is essential for predicting the pharmacokinetic (PK) parameters that underpin dosing and dosage frequency. Further, characterization of the enzyme(s) responsible for metabolism (reaction phenotyping) allows prediction, at least at the qualitative level, of factors (including metabolic drug-drug interactions) likely to alter the clearance of both new chemical entities (NCEs) and established drugs. Microsomes are typically used as the enzyme source for the measurement of metabolic stability and for reaction phenotyping because they express the major drug-metabolizing enzymes cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT), along with others that contribute to drug metabolism. Described in this unit are methods for microsome isolation, as well as for the determination of metabolic stability and metabolite formation (including kinetics). © 2016 by John Wiley & Sons, Inc. PMID:27636111

  15. Antiretroviral drug levels and interactions affect lipid, lipoprotein and glucose metabolism in HIV-1 seronegative subjects: A pharmacokinetic-pharmacodynamic analysis

    PubMed Central

    Rosenkranz, Susan L.; Yarasheski, Kevin E.; Para, Michael F.; Reichman, Richard C.; Morse, Gene D.

    2007-01-01

    Background: HIV-infected patients treated with antiretroviral medications (ARVs) develop undesirable changes in lipid and glucose metabolism that mimic the metabolic syndrome and may be proatherogenic. Antiretroviral drug levels and their interactions may contribute to these metabolic alterations. Methods: Fifty-six HIV-seronegative adults were enrolled in an open-label, randomized, pharmacokinetic interaction study, and received a non-nucleoside reverse transcriptase inhibitor (efavirenz on days 1-21) plus a protease inhibitor (PI; amprenavir on days 11-21), with a second PI on days 15-21 (saquinavir, nelfinavir, indinavir, or ritonavir). Fasting triglycerides, total, LDL- and HDL-cholesterol, glucose, insulin and C-peptide levels were measured on days 0, 14, 21, and 2-3 weeks after discontinuing drugs. Regression models were used to estimate changes in these parameters and associations between these changes and circulating levels of study drugs. Results: Short-term efavirenz and amprenavir administration significantly increased cholesterol, triglycerides and glucose levels. Addition of a second protease inhibitor further increased triglycerides, total- and LDL-cholesterol levels. Higher amprenavir levels predicted larger increases in triglycerides, total and LDL-cholesterol. Two weeks after all study drugs were stopped, total, LDL- and HDL-cholesterol remained elevated above baseline. Conclusions: ARV regimens that include a non-nucleoside reverse transcriptase inhibitor plus single or boosted PIs are becoming more common, but the pharmacodynamic interactions associated with these regimens can result in persistent, undesirable alterations in serum lipid/lipoprotein levels. Additional pharmacodynamic studies are needed to examine the metabolic effects of ritonavir-boosted regimens, with and without efavirenz. PMID:18007962

  16. Factors affecting gallbladder motility: drugs.

    PubMed

    Marzio, L

    2003-07-01

    Various drugs and medications that inhibit or stimulate gallbladder contraction and basal tone in humans are described. Active gallbladder contraction may be achieved using synthetic hormones such as cholecystokinin, caerulein and motilin, cholinomimetic drugs such as bethanecol, prostigmine, and erythromycin due to its motilin-like effect. Furthermore, cisapride and cholestyramine, may have some excitatory activity on the gallbladder muscle. Intravenous amino acids also induce gallbladder contraction through the release of cholecystokinin. Inhibition of gallbladder contraction induced by a meal, or reduction of the basal fasting tone may be achieved by using atropine and other cholinergics, and by inhibitory hormones such as somatostatin, the nitric acid releaser arginine, the calcium channel antagonist nifedipine, and progesterone. Other drugs such as trimebutine, loperamide and ondansetron may negatively affect gallbladder contraction. PMID:12974504

  17. [Pathogenetic correction of metabolic disturbances in chronic liver affections].

    PubMed

    Romantsov, M G; Petrov, A Iu; Aleksandrova, L N; Sukhanov, D S; Kovalenko, A L

    2012-01-01

    The available drugs for the treatment of chronic liver affections (the adequate model is chronic hepatitis C) include agents of metabolic therapy, whose efficacy is not always enough, that required the search for original mitochondrial substrates on the basis of succinate. Such agents were composed as a pharmaceutical group named "Substrates of Energetic Metabolism" or "Substrate Antihypoxants". The review presents the description of the pharmacological effects of remaxole and cytoflavin, evident from lower levels of active metabolites of oxygen that increases the clinical efficacy of the therapy. Their role in the metabolic reactions in chronic liver affections is exclusive and rather actual. PMID:23700935

  18. Drug metabolism by the human fetus.

    PubMed

    Juchau, M R; Chao, S T; Omiecinski, C J

    1980-01-01

    A review of the literature that pertains to drug biotransformation in human fetal tissues reveals that, in spite of several publications in this comparatively new area of research, only very limited definitive information is currently available. The large majority of the studies performed have dealt with the cytochrome P-450-dependent microsomal mono-oxygenase systems and for several of the common drug metabolising reactions, very little or no data are available at this time. Some of the more important data that have emerged include observations that important bioactivation reactions can be demonstrated in human fetal tissues obtained during the period of late embryogenesis (high susceptibility to chemical dysmorphogenesis) and that the human fetal adrenal gland possesses considerable capacity to catalyse several important oxidation-reduction reactions. From the data available to date, it would appear that, in most instances, the biotransformation of drugs in the human embryo and fetus would not affect maternal plasma concentrations significantly. From the viewpoint of parameters of the pharmacokinetics of parent drug (or other xenobiotic) substrates under steady-state conditions, human fetal drug metabolism probably is of little consequence in most cases, although exceptions may exist. Pharmacokinetic parameters observed after isolated exposure, however, are very likely to be affected, perhaps markedly, in some instances. The demonstrated capacity of human prenatal tissues and cells to generate reactive intermediary metabolites, including those that produce mutations, has attracted the greatest attention recently. This capacity may be associated with extremely important adverse reactions to drugs and other environmental chemicals. Such adverse responses include transplacental mutagenesis, carcinogenesis, dysmorphogenesis, and perhaps several other undesirable effects. Although far from conclusive, the data tend to suggest that humans and subhuman primates may be

  19. Factors affecting the response to inhibition of drug metabolism by cimetidine--dose response and sensitivity of elderly and induced subjects.

    PubMed Central

    Feely, J; Pereira, L; Guy, E; Hockings, N

    1984-01-01

    The effect of cimetidine on oxidative drug metabolism was characterised using antipyrine clearance in a group of healthy volunteers. In six subjects cimetidine produced a dose dependent reduction of antipyrine clearance: 400 mg/day (16.8 +/- 2.2%, mean +/- s.e. mean), 800 mg/day (26.3 +/- 1.5%) and 1600 mg/day (33.5 +/- 2.4%). The effect of cimetidine (800 mg/day) was of similar magnitude (approximately 25%) in two groups of six young (21-26 years) and six elderly (65-78 years) subjects. The effect of pretreatment begun just 1 h before administration of antipyrine was similar to that of 24 h pretreatment and that reported for chronic cimetidine pretreatment. The percentage reduction in antipyrine clearance produced by cimetidine 800 mg/day was greater (44 +/- 5 vs 24 +/- 3%; P less than 0.05) in six subjects who had been pretreated with the hepatic enzyme inducer rifampicin (600 mg/day for 21 days) than in the control uninduced state. Although cimetidine was capable of rapidly reversing the effect of rifampicin on antipyrine clearance, following withdrawal of both rifampicin and cimetidine there was still evidence of enzyme induction. These results suggest that the effect of cimetidine on oxidative metabolism is dose dependent, is more marked in enzyme induced subjects, is independent of the duration of pretreatment and is of similar magnitude in young and elderly subjects. PMID:6691891

  20. [Affective disorders: endocrine and metabolic comorbidities].

    PubMed

    Cermolacce, M; Belzeaux, R; Adida, M; Azorin, J-M

    2014-12-01

    Links between affective and endocrine-metabolic disorders are numerous and complex. In this review, we explore most frequent endocrine-metabolic comorbidities. On the one hand, these comorbidities imply numerous iatrogenic effects from antipsychotics (metabolic side-effects) or from lithium (endocrine side-effects). On the other hand, these comorbidities are also associated with affective disorders independently from medication. We will successively examine metabolic syndrome, glycemic disturbances, obesity and thyroid disorders among patients with affective disorders. Endocrinemetabolic comorbidities can be individually encountered, but can also be associated. Therefore, they substantially impact morbidity and mortality by increasing cardiovascular risk factors. Two distinct approaches give an account of processes involved in these comorbidities: common environmental factors (iatrogenic effects, lifestyle), and/or shared physiological vulnerabilities. In conclusion, we provide a synthesis of important results and recommendations related to endocrine-metabolic comorbidities in affective disorders : heavy influence on morbidity and mortality, undertreatment of somatic diseases, importance of endocrine and metabolic side effects from main mood stabilizers, impact from sex and age on the prevalence of comorbidities, influence from previous depressive episodes in bipolar disorders, and relevance of systematic screening for subclinical (biological) disturbances. PMID:25550238

  1. Automated method for study of drug metabolism

    NASA Technical Reports Server (NTRS)

    Furner, R. L.; Feller, D. D.

    1973-01-01

    Commercially available equipment can be modified to provide automated system for assaying drug metabolism by continuous flow-through. System includes steps and devices for mixing drug with enzyme and cofactor in the presence of pure oxygen, dialyzing resulting metabolite against buffer, and determining amount of metabolite by colorimetric method.

  2. Metabolic Network Prediction of Drug Side Effects.

    PubMed

    Shaked, Itay; Oberhardt, Matthew A; Atias, Nir; Sharan, Roded; Ruppin, Eytan

    2016-03-23

    Drug side effects levy a massive cost on society through drug failures, morbidity, and mortality cases every year, and their early detection is critically important. Here, we describe the array of model-based phenotype predictors (AMPP), an approach that leverages medical informatics resources and a human genome-scale metabolic model (GSMM) to predict drug side effects. AMPP is substantially predictive (AUC > 0.7) for >70 drug side effects, including very serious ones such as interstitial nephritis and extrapyramidal disorders. We evaluate AMPP's predictive signal through cross-validation, comparison across multiple versions of a side effects database, and co-occurrence analysis of drug side effect associations in scientific abstracts (hypergeometric p value = 2.2e-40). AMPP outperforms a previous biochemical structure-based method in predicting metabolically based side effects (aggregate AUC = 0.65 versus 0.59). Importantly, AMPP enables the identification of key metabolic reactions and biomarkers that are predictive of specific side effects. Taken together, this work lays a foundation for future detection of metabolically grounded side effects during early stages of drug development. PMID:27135366

  3. Affective Disorders, Bone Metabolism, and Osteoporosis.

    PubMed

    Mezuk, Briana

    2008-12-01

    The nature of the relationship between affective disorders, bone mineral density (BMD), and bone metabolism is unresolved, although there is growing evidence that many medications used to treat affective disorders are associated with low BMD or alterations in neuroendocrine systems that influence bone turnover. The objective of this review is to describe the current evidence regarding the association of unipolar and bipolar depression with BMD and indicators of bone metabolism, and to explore potential mediating and confounding influences of those relationships. The majority of studies of unipolar depression and BMD indicate that depressive symptoms are associated with low BMD. In contrast, evidence regarding the relationship between bipolar depression and BMD is inconsistent. There is limited but suggestive evidence to support an association between affective disorders and some markers of bone turnover. Many medications used to treat affective disorders have effects on physiologic systems that influence bone metabolism, and these conditions are also associated with a range of health behaviors that can influence osteoporosis risk. Future research should focus on disentangling the pathways linking psychotropic medications and their clinical indications with BMD and fracture risk.

  4. Affective Disorders, Bone Metabolism, and Osteoporosis

    PubMed Central

    2013-01-01

    The nature of the relationship between affective disorders, bone mineral density (BMD), and bone metabolism is unresolved, although there is growing evidence that many medications used to treat affective disorders are associated with low BMD or alterations in neuroendocrine systems that influence bone turnover. The objective of this review is to describe the current evidence regarding the association of unipolar and bipolar depression with BMD and indicators of bone metabolism, and to explore potential mediating and confounding influences of those relationships. The majority of studies of unipolar depression and BMD indicate that depressive symptoms are associated with low BMD. In contrast, evidence regarding the relationship between bipolar depression and BMD is inconsistent. There is limited but suggestive evidence to support an association between affective disorders and some markers of bone turnover. Many medications used to treat affective disorders have effects on physiologic systems that influence bone metabolism, and these conditions are also associated with a range of health behaviors that can influence osteoporosis risk. Future research should focus on disentangling the pathways linking psychotropic medications and their clinical indications with BMD and fracture risk. PMID:23874147

  5. Overview of Extracellular Microvesicles in Drug Metabolism

    PubMed Central

    Conde-Vancells, Javier; Gonzalez, Esperanza; Lu, Shelly C.; Mato, Jose M.; Falcon-Perez, Juan M.

    2010-01-01

    Importance of the field Liver is the major body reservoir for enzymes involved in the metabolism of endogenous and xenobiotic compounds. Recently, it has been shown that hepatocytes release exosome-like vesicles to the extracellular medium, and the proteomic characterization of these hepatocyte-secreted exosomes has revealed the presence of several of these enzymes on them. Areas covered in this review A systematic bibliographic search focus on two related aspects: 1) xenobiotic-metabolizing enzymes that have been detected in microvesicles, and 2) microvesicles which are in the blood stream or secreted by cell-types with clear interactions with this fluid. What the reader will gain A discussion of these hepatocyte-secreted vesicles along with others microvesicles as enzymatic carriers in the context of extrahepatic drug-metabolizing systems. Take home message The contribution of many tissues including the liver to the microvesicles plasma population is supported by several reports. On the other hand, many enzymes involved in the metabolism of drugs have been detected in microvesicles. Together, these observations argue positively through a role of hepatic-microvesicles in spreading the liver metabolizing activities through the body contributing in this manner to extrahepatic drug metabolism systems what could be relevant for body homeostasis and pharmaceutical interests. PMID:20192903

  6. Dyslipidemic drugs in metabolic syndrome

    PubMed Central

    Siddiqi, Sheelu S.; Misbahuddin; Ahmad, Farida; Rahman, Syed Z.; Khan, Asad U.

    2013-01-01

    Introduction: Metabolic syndrome predisposes to diabetes and atherosclerotic vascular disease. Statins reduce cardiovascular events, so all metabolic syndrome patients should be evaluated for dyslipidemia. Many patients fail to achieve lipid goals with statin monotherapy. Co-administration of ezetimibe (EZE) and atorvastatin (ATV) may enable more patients to achievelow-density lipoproteincholesterol (LDL-C) goal while avoiding risks of high-dose statin monotherapy. Materials and Methods: The present study compares rosuvastatin (Rsv) with a combination of (Atv) and (Eze). Metabolic syndrome patients, 30-70 years with LDL-C ≥130 mg/dl and a 10-year CHD risk score of 10% were randomized to double-blind treatment with (Rsv) 5 mg (n = 67) or (Atv) 10 mg+(Eze) 10 mg (n = 68) for 12 weeks. Results: LDL-C reduced significantly; (32.3% and 30.3%, P < 0.001) in (Atv)+(Eze) and (Rsv), respectively, but there was no significant difference between two arms. More patients achieved LDL-C goal of ≤100 mg/dl with (Atv)+(Eze) compared to (Rsv) (65% vs. 58%, P < 0.05). Triglycerides (TG) were reduced more with (Atv)+(Eze) compared to (Rsv) (28.1% and 21.4%, P < 0.001). Greater increase in high-density lipoprotein cholesterol (HDL-C) was observed with (Atv)+(Eze). Both treatments were well tolerated. Conclusion: This study shows that the combination of (Atv)+(Eze) has more efficacy and comparable safety to that of (Rsv). PMID:23869305

  7. 21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Drug metabolizing enzyme genotyping system. 862... Test Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification. A drug metabolizing enzyme genotyping system is a device intended for use in testing deoxyribonucleic acid...

  8. 21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Drug metabolizing enzyme genotyping system. 862... Test Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification. A drug metabolizing enzyme genotyping system is a device intended for use in testing deoxyribonucleic acid...

  9. 21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Drug metabolizing enzyme genotyping system. 862... Test Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification. A drug metabolizing enzyme genotyping system is a device intended for use in testing deoxyribonucleic acid...

  10. 21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Drug metabolizing enzyme genotyping system. 862... Test Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification. A drug metabolizing enzyme genotyping system is a device intended for use in testing deoxyribonucleic acid...

  11. 21 CFR 862.3360 - Drug metabolizing enzyme genotyping system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Drug metabolizing enzyme genotyping system. 862... Test Systems § 862.3360 Drug metabolizing enzyme genotyping system. (a) Identification. A drug metabolizing enzyme genotyping system is a device intended for use in testing deoxyribonucleic acid...

  12. Pharmacogenomic and clinical data link non-pharmacokinetic metabolic dysregulation to drug side effect pathogenesis

    PubMed Central

    Zielinski, Daniel C.; Filipp, Fabian V.; Bordbar, Aarash; Jensen, Kasper; Smith, Jeffrey W.; Herrgard, Markus J.; Mo, Monica L.; Palsson, Bernhard O.

    2015-01-01

    Drug side effects cause a significant clinical and economic burden. However, mechanisms of drug action underlying side effect pathogenesis remain largely unknown. Here, we integrate pharmacogenomic and clinical data with a human metabolic network and find that non-pharmacokinetic metabolic pathways dysregulated by drugs are linked to the development of side effects. We show such dysregulated metabolic pathways contain genes with sequence variants affecting side effect incidence, play established roles in pathophysiology, have significantly altered activity in corresponding diseases, are susceptible to metabolic inhibitors and are effective targets for therapeutic nutrient supplementation. Our results indicate that metabolic dysregulation represents a common mechanism underlying side effect pathogenesis that is distinct from the role of metabolism in drug clearance. We suggest that elucidating the relationships between the cellular response to drugs, genetic variation of patients and cell metabolism may help managing side effects by personalizing drug prescriptions and nutritional intervention strategies. PMID:26055627

  13. Discussion-Based Instruction in Drug Metabolism.

    ERIC Educational Resources Information Center

    Ruenitz, Peter C.

    1995-01-01

    A flexible strategy for large-group pharmacy instruction in drug metabolism has students prepare and discuss answers to fact-oriented study questions, addressing fundamentals covered in a textbook, with regular evaluation of in-class student responses to higher-order review questions. This discussion-based approach has brought sustained…

  14. Drug Targets in Mycobacterial Sulfur Metabolism

    PubMed Central

    Bhave, Devayani P.; Muse, Wilson B.; Carroll, Kate S.

    2011-01-01

    The identification of new antibacterial targets is urgently needed to address multidrug resistant and latent tuberculosis infection. Sulfur metabolic pathways are essential for survival and the expression of virulence in many pathogenic bacteria, including Mycobacterium tuberculosis. In addition, microbial sulfur metabolic pathways are largely absent in humans and therefore, represent unique targets for therapeutic intervention. In this review, we summarize our current understanding of the enzymes associated with the production of sulfated and reduced sulfur-containing metabolites in Mycobacteria. Small molecule inhibitors of these catalysts represent valuable chemical tools that can be used to investigate the role of sulfur metabolism throughout the Mycobacterial lifecycle and may also represent new leads for drug development. In this light, we also summarize recent progress in the development of inhibitors of sulfur metabolism enzymes. PMID:17970225

  15. Nano-based drug delivery system enhances the oral absorption of lipophilic drugs with extensive presystemic metabolism.

    PubMed

    Zhang, Zhiwen; Gao, Fang; Jiang, Shijun; Ma, Li; Li, Yaping

    2012-10-01

    Oral administration remains the most preferred route for the treatment of many diseases due to its convenience and adaptability. However, the presystemic metabolism may be an important barrier that prevents lipophilic drugs from achieving their pharmacological effects following oral delivery. Nano-based drug delivery system provides an effective strategy to reduce the presystemic metabolism and increase the systemic exposure of lipophilic drugs. In this review, we described the physiological factors affecting the presystemic metabolism of lipophilic drugs, intestinal transport of nanosystems, strategy of nanosystems to avoid the presystemic metabolism, and the current application of various oral nanosystems including lipid and polymeric nanocarriers. The nano-based drug delivery system has a lot of potential for reducing the presystemic metabolism and enhancing the bioavailability of orally administrated lipophilic drugs.

  16. Effects of alcohol on human carboxylesterase drug metabolism

    PubMed Central

    Parker, Robert B.; Hu, Zhe-Yi; Meibohm, Bernd; Laizure, S. Casey

    2015-01-01

    Background and Objective Human carboxylesterase-1 (CES1) and human carboxylesterase-2 (CES2) play an important role in metabolizing many medications. Alcohol is a known inhibitor of these enzymes but the relative effect on CES1 and CES2 is unknown. The aim of this study is to determine the impact of alcohol on the metabolism of specific probes for CES1 (oseltamivir) and CES2 (aspirin). Methods The effect of alcohol on CES1- and CES2-mediated probe drug hydrolysis was determined in vitro using recombinant human carboxylesterase. To characterize the in vivo effects of alcohol, healthy volunteers received each probe drug alone and in combination with alcohol followed by blood sample collection and determination of oseltamivir, aspirin, and respective metabolite pharmacokinetics. Results Alcohol significantly inhibited oseltamivir hydrolysis by CES1 in vitro but did not affect aspirin metabolism by CES2. Alcohol increased the oseltamivir area under the plasma concentration-time curve (AUC) from 0-6 h by 27% (range 11-46%, p=0.011) and decreased the metabolite/oseltamivir AUC 0-6 h ratio by 34% (range 25-41%, p<0.001). Aspirin pharmacokinetics were not affected by alcohol. Conclusions Alcohol significantly inhibited the hydrolysis of oseltamivir by CES1 both in vitro and in humans, but did not affect the hydrolysis of aspirin to salicylic acid by CES2. These results suggest that alcohol's inhibition of CES1 could potentially result in clinically significant drug interactions with other CES1-substrate drugs, but it is unlikely to significantly affect CES2-substrate drug hydrolysis. PMID:25511794

  17. Trichoderma secondary metabolites that affect plant metabolism.

    PubMed

    Vinale, Francesco; Sivasithamparam, Krishnapillai; Ghisalberti, Emilio L; Ruocco, Michelina; Wood, Sheridan; Lorito, Matteo

    2012-11-01

    Recently, there have been many exciting new developments relating to the use of Trichoderma spp. as agents for biocontrol of pathogens and as plant growth promoters. Several mechanisms have been proposed to explain the positive effects of these microorganisms on the plant host. One factor that contributes to their beneficial biological activities is related to the wide variety of metabolites that they produce. These metabolites have been found not only to directly inhibit the growth and pathogenic activities of the parasites, but also to increase disease resistance by triggering the system of defence in the plant host. In addition, these metabolites are also capable of enhancing plant growth, which enables the plant to counteract the disease with compensatory vegetative growth by the augmented production of root and shoot systems. This review takes into account the Trichoderma secondary metabolites that affect plant metabolism and that may play an important role in the complex interactions of this biocontrol agent with the plant and pathogens.

  18. Ontogeny and drug metabolism in newborns.

    PubMed

    Dotta, Andrea; Chukhlantseva, Natalia

    2012-10-01

    In pediatric age and particularly in newborn infants the drug efficacy and safety are influenced by the growth and development on drug Absorption, Distribution, Metabolism and Excretion (ADME). Thanks to the fast development of pharmacogenomics and pharmacogenetics, the drug therapy promises to be adapted to the genetic profile of the individual, reducing considerably the side effects of drugs and increasing their efficacy. Interindividual variability in drug response is well known in both adults and children. Such a variability is multifactorial considering both intrinsic and extrinsic factors. Drug distribution in the neonate is influenced by a variety of age-dependent factors as a total body water content and distribution variations, role of drug transporters, blood/tissue protein binding, blood and tissue pH and perfusion. The development of enzymes involved in human metabolism were classified in 3 categories: 1) those expressed during the whole or part of the fetal period, but silenced or expressed at low levels within 1-2 years after birth; 2) those expressed at relatively constant levels throughout fetal development, but increased to some extent postnatally; and 3) those whose onset of expression can occur in the third trimester, but substantial increase is noted in the first 1-2 years after birth. Besides this intrinsic aspects influencing pharmacokinetics during the neonatal period there are other important events such as inborn or acquired diseases, environment and finally pharmacogenetics and pharmacogenomics. Thousands of deaths every years are caused by fatal drug reactions; among the potential causes there are not only the severity of the disease being treated, drug interactions, nutritional status, renal and liver functions, but also the inherited differences in drug metabolism and genetic polymorphism. Adverse drug reactions (ADRs) among pediatric patients have been shown to be three times more frequent than in adults. On August 2010 The National

  19. Novel metabolic drugs and blood pressure: implications for the treatment of obese hypertensive patients?

    PubMed

    Engeli, Stefan; Jordan, Jens

    2013-10-01

    Hypertension and obesity often coexist, exposing patients to cardiovascular and metabolic risks, particularly type 2 diabetes mellitus. Moreover, obesity may render hypertensive patients treatment resistant. We review how drugs recently approved for obesity or type 2 diabetes mellitus treatment affect blood pressure. The weight-reducing drug lorcaserin induces modest reductions in body weight while slightly improving blood pressure. The fixed low-dose topiramate/phentermine combinations elicit larger reductions in body weight and blood pressure. Concomitant improvements in glucose metabolism, adiposity, and blood pressure differentiate the first clinically available SGLT2 inhibitor dapagliflozin from other oral antidiabetic drugs. Yet, the mechanisms through which metabolic drugs affect blood pressure and their interaction with antihypertensive drugs are poorly understood. Blood pressure-lowering effects of metabolic drugs could be exploited in the clinical management of obese hypertensive patients with and without type 2 diabetes mellitus, particularly in patients with difficult to control arterial hypertension. PMID:23933756

  20. Genetic polymorphisms affect efficacy and adverse drug reactions of DMARDs in rheumatoid arthritis.

    PubMed

    Zhang, Ling Ling; Yang, Sen; Wei, Wei; Zhang, Xue Jun

    2014-11-01

    Disease-modifying antirheumatic drugs (DMARDs) and biological agents are critical in preventing the severe complications of rheumatoid arthritis (RA). However, the outcome of treatment with these drugs in RA patients is quite variable and unpredictable. Drug-metabolizing enzymes (dihydrofolate reductase, cytochrome P450 enzymes, N-acetyltransferases, etc.), drug transporters (ATP-binding cassette transporters), and drug targets (tumor necrosis factor-α receptors) are coded for by variant alleles. These gene polymorphisms may influence the pharmacokinetics, pharmacodynamics, and side effects of medicines. The cause for differences in efficacy and adverse drug reactions may be genetic variation in drug metabolism among individuals. Polymorphisms in drug transporter genes may change the distribution and excretion of medicines, and the sensitivity of the targets to drugs is strongly influenced by genetic variations. In this article, we review the genetic polymorphisms that affect the efficacy of DMARDs or the occurrence of adverse drug reactions associated with DMARDs in RA.

  1. Interplay of drug metabolizing enzymes with cellular transporters.

    PubMed

    Böhmdorfer, Michaela; Maier-Salamon, Alexandra; Riha, Juliane; Brenner, Stefan; Höferl, Martina; Jäger, Walter

    2014-11-01

    Many endogenous and xenobiotic substances and their metabolites are substrates for drug metabolizing enzymes and cellular transporters. These proteins may not only contribute to bioavailability of molecules but also to uptake into organs and, consequently, to overall elimination. The coordinated action of uptake transporters, metabolizing enzymes, and efflux pumps, therefore, is a precondition for detoxification and elimination of drugs. As the understanding of the underlying mechanisms is important to predict alterations in drug disposal, adverse drug reactions and, finally, drug-drug interactions, this review illustrates the interplay between selected uptake/efflux transporters and phase I/II metabolizing enzymes.

  2. Links between nutrition, drug abuse, and the metabolic syndrome.

    PubMed

    Virmani, Ashraf; Binienda, Zbigniew; Ali, Syed; Gaetani, Franco

    2006-08-01

    Nutritional deficiency in combination with drug abuse may increase risk of developing the metabolic syndrome by augmenting cell damage, excitotoxicity, reducing energy production, and lowering the antioxidant potential of the cells. We have reviewed here the following points: effects of drugs of abuse on nutrition and brain metabolism; effects of nutrition on actions of the drugs of abuse; drug abuse and probability of developing metabolic syndrome; role of genetic vulnerability in nutrition/drug abuse and brain damage; and the role of neuroprotective supplements in drug abuse. Nutrition education is an essential component of substance abuse treatment programs and can enhance substance abuse treatment outcomes. The strategies available, in particular the nutritional approach to protect the drug abusers from the metabolic syndrome and other diseases are discussed.

  3. In vitro evaluation of metabolic drug-drug interactions: a descriptive and critical commentary.

    PubMed

    Li, Albert P

    2007-01-01

    Adverse drug-drug interactions represent a major challenge for the pharmaceutical industry. Recently, in vitro approaches for the evaluation of metabolism-related drug-drug interactions have been developed. These in vitro approaches are found to be useful in the assessment of clinical drug-drug interaction potential of new chemical entities and to aid the understanding of clinically significant drug-drug interactions observed with existing drugs. The general methods for the evaluation of drug-drug interactions using in vitro, human-based experimental systems are described and critically reviewed.

  4. Chemistry, pharmacology, and metabolism of emerging drugs of abuse.

    PubMed

    Maurer, Hans H

    2010-10-01

    In recent years, besides the classic designer drugs of the amphetamine type, a series of new drug classes appeared on the illicit drugs market. The chemistry, pharmacology, toxicology, metabolism, and toxicokinetics is discussed of 2,5-dimethoxy amphetamines, 2,5-dimethoxy phenethylamines, beta-keto-amphetamines, phencyclidine derivatives as well as of herbal drugs, ie, Kratom. They have gained popularity and notoriety as rave drugs. The metabolic pathways, the involvement of cytochrome P450 isoenzymes in the main pathways, and their roles in hepatic clearance are also summarized. PMID:20683389

  5. 75 FR 5333 - Endocrinologic and Metabolic Drugs Advisory Committee; Cancellation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-02

    ... was announced in the Federal Register of January 19, 2010 (75 FR 2875). This meeting has been... HUMAN SERVICES Food and Drug Administration Endocrinologic and Metabolic Drugs Advisory Committee; Cancellation AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The meeting of...

  6. Relevance of induction of human drug-metabolizing enzymes: pharmacological and toxicological implications

    PubMed Central

    PARK, B. K.; KITTERINGHAM, N. R.; PIRMOHAMED, M.; TUCKER, G. T.

    1996-01-01

    1Human drug-metabolizing systems can be induced, or activated, by a large number of exogenous agents including drugs, alcohol, components in the diet and cigarette smoke, as well as by endogenous factors. 2Such perturbation of enzyme activity undoubtedly contributes to both intra- and inter-individual variation both with respect to the rate and route of metabolism for a particular drug. Induction may, in theory, either attenuate the pharmacological response or exacerbate the toxicity of a particular drug, or both. 3The clinical impact of enzyme induction will depend upon the number of different enzyme isoforms affected and the magnitude of the inductive response within an individual, and also on the therapeutic indices of the affected substrates. 4The toxicological implications will be determined either by any change in the route of metabolism, or by a disturbance of the balance between activation and detoxication processes, which may be isozyme selective. PMID:8799511

  7. The effects of estrus cycle on drug metabolism in the rat.

    PubMed

    Brandstetter, Y; Kaplanski, J; Leibson, V; Ben-Zvi, Z

    1986-01-01

    The effect of the female rat estral cycle on microsomal drug metabolism in-vivo and in-vitro has been studied. Two microsomal enzymes, aminopyrine-N-demethylase and aniline hydroxylase showed a greater specific activity (p less than 0.01) in the diestrus phase of the estral cycle while the oxidative enzyme aryl hydrocarbon hydroxylase and the conjugative enzyme, glucuronyl transferase, were not affected. In vivo studies which included theophylline and antipyrine metabolism, and hexobarbital sleeping times showed no difference between the different phases of the estral cycle. Conflicting evidence about the effect of steroid sex hormones on hepatic drug metabolism is discussed.

  8. Drug Convictions May Affect Your Student Aid.

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC.

    This booklet explains problems posed by prior drug convictions to college-bound students seeking federal financial aid. Under a new law which takes effect on July 1, 2000, some students who have drug convictions may be ineligible for federal student aid. For possession of illegal drugs, students are ineligible from the date of conviction for one…

  9. Drug-metabolism mechanism: Knowledge-based population pharmacokinetic approach for characterizing clobazam drug-drug interactions.

    PubMed

    Tolbert, Dwain; Bekersky, Ihor; Chu, Hui-May; Ette, Ene I

    2016-03-01

    A metabolic mechanism-based characterization of antiepileptic drug-drug interactions (DDIs) with clobazam in patients with Lennox-Gastaut syndrome (LGS) was performed using a population pharmacokinetic (PPK) approach. To characterize potential DDIs with clobazam, pharmacokinetic (PK) data from 153 patients with LGS in study OV-1012 (NCT00518713) and 18 healthy participants in bioavailability study OV-1017 were pooled. Antiepileptic drugs (AEDs) were grouped based on their effects on the cytochrome P450 (CYP) isozymes responsible for the metabolism of clobazam and its metabolite, N-desmethylclobazam (N-CLB): CYP3A inducers (phenobarbital, phenytoin, and carbamazepine), CYP2C19 inducers (valproic acid, phenobarbital, phenytoin, and carbamazepine), or CYP2C19 inhibitors (felbamate, oxcarbazepine). CYP3A4 inducers-which did not affect the oral clearance of clobazam-significantly increased the formation of N-CLB by 9.4%, while CYP2C19 inducers significantly increased the apparent elimination rate of N-CLB by 10.5%, resulting in a negligible net change in the PK of the active metabolite. CYP2C19 inhibitors did not affect N-CLB elimination. Because concomitant use of AEDs that are either CYP450 inhibitors or inducers with clobazam in the treatment of LGS patients had negligible to no effect on clobazam PK in this study, dosage adjustments may not be required for clobazam in the presence of the AEDs investigated here.

  10. Inherited metabolic diseases affecting the carrier.

    PubMed

    Endres, W

    1997-03-01

    The objective of this review is to draw attention to those inherited metabolic traits which are potentially harmful also for the carrier, and to outline preventive measures, at least for obligate heterozygotes, i.e. parents of homozygous children. Concerning carriers of food-dependent abnormalities, early vascular disease in homocystinuria, hyperammonaemic episodes in ornithine transcarbamylase deficiency, presenile cataracts in galactosaemia as well as galactokinase deficiency, spastic paraparesis in X-linked adrenoleukodystrophy, and HELLP syndrome in mothers of babies with long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency have to be mentioned. In the group of food-independent disorders, clinical features in carriers may be paraesthesias and corneal dystrophy in Fabry disease, lens clouding in Lowe syndrome, lung and/or liver diseases in alpha 1-antitrypsin deficiency, and renal stones in cystinuria type II and III. Finally, two monogenic carrier states are known which in pregnant individuals could possibly afflict the developing fetus, i.e. heterozygosity for galactosaemia and for phenylketonuria. Elevated levels of galactose-1-phosphate have been found in red blood cells of infants heterozygous for galactosaemia born to heterozygous mothers. Aspartame in very high doses is reported to increase blood phenylalanine levels in heterozygotes for phenylketonuria, thus being a risk for the fetus of a heterozygous mother. For some of these carrier states preventive measures can be recommended, e.g. restriction of lactose in parents and heterozygous grandparents of children with galactosaemia and galactokinase deficiency as well as transiently in infants heterozygous for galactosaemia, dietary supplementation with monounsaturated fatty acids in symptomatic carriers for X-linked adrenoleukodystrophy, avoidance of smoking and alcohol in heterozygotes for alpha 1-antitrypsin deficiency, avoidance of episodes of dehydration in heterozygotes for cystinuria, and

  11. Role of Cytochrome P450 Monooxygenase in Carcinogen and Chemotherapeutic Drug Metabolism.

    PubMed

    Wahlang, B; Falkner, K Cameron; Cave, Matt C; Prough, Russell A

    2015-01-01

    The purpose of this chapter is to provide insight into which human cytochromes P450 (CYPs) may be involved in metabolism of chemical carcinogens and anticancer drugs. A historical overview of this field and the development of literature using relevant animal models and expressed human CYPs have provided information about which specific CYPs may be involved in carcinogen metabolism. Definition of the biochemical properties of CYP activity came from several groups who studied the reaction stoichiometry of butter yellow and benzo[α]pyrene, including their role in induction of these enzyme systems. This chapter will list as much as is known about the human CYPs involved in carcinogen and anticancer drug metabolism, as well as summarize studies with rodent CYPs. A review of three major classes of anticancer drugs and their metabolism in humans is covered for cyclophosphamide, procarbazine, and anthracycline antibiotics, cancer chemotherapeutic compounds extensively metabolized by CYPs. The emerging information about human CYP gene polymorphisms as well as other enzymes involved in foreign compound metabolism provides considerable information about how these genetic variants affect carcinogen and anticancer drug metabolism. With information available from individual's genomic sequences, consideration of populations who may be at risk due to environmental exposure to carcinogens or how to optimize their cancer therapy regimens to enhance efficacy of the anticancer drugs appears to be an important field of study to benefit individuals in the future. PMID:26233902

  12. Cancer Metabolism: New Validated Targets for Drug Discovery

    PubMed Central

    Sotgia, Federica; Martinez-Outschoorn, Ubaldo E.; Lisanti, Michael P.

    2013-01-01

    Recent studies in cancer metabolism directly implicate catabolic fibroblasts as a new rich source of i) energy and ii) biomass, for the growth and survival of anabolic cancer cells. Conversely, anabolic cancer cells upregulate oxidative mitochondrial metabolism, to take advantage of the abundant fibroblast fuel supply. This simple model of “metabolic-symbiosis” has now been independently validated in several different types of human cancers, including breast, ovarian, and prostate tumors. Biomarkers of metabolic-symbiosis are excellent predictors of tumor recurrence, metastasis, and drug resistance, as well as poor patient survival. New pre-clinical models of metabolic-symbiosis have been generated and they genetically validate that catabolic fibroblasts promote tumor growth and metastasis. Over 30 different stable lines of catabolic fibroblasts and >10 different lines of anabolic cancer cells have been created and are well-characterized. For example, catabolic fibroblasts harboring ATG16L1 increase tumor cell metastasis by >11.5-fold, despite the fact that genetically identical cancer cells were used. Taken together, these studies provide >40 novel validated targets, for new drug discovery and anti-cancer therapy. Since anabolic cancer cells amplify their capacity for oxidative mitochondrial metabolism, we should consider therapeutically targeting mitochondrial biogenesis and OXPHOS in epithelial cancer cells. As metabolic-symbiosis promotes drug-resistance and may represent the escape mechanism during anti-angiogenic therapy, new drugs targeting metabolic-symbiosis may also be effective in cancer patients with recurrent and advanced metastatic disease. PMID:23896568

  13. [In Vitro and in Vivo Assessments of Drug-induced Hepatotoxicity and Drug Metabolism in Humans].

    PubMed

    Sanoh, Seigo

    2015-01-01

    Drug-induced hepatotoxicity is of concern in drug discovery and development. Reactive metabolites generated by drug metabolizing enzymes in the liver contribute to the induction of hepatotoxicity. Therefore, drug-induced hepatotoxicity, drug metabolism, and pharmacokinetics were evaluated in vitro and in vivo in this pre-clinical study. First, hepatotoxicity was tested in vitro using three-dimensional hepatocyte cultures. Hepatocyte spheroids formed in the three-dimensional culture systems maintain various liver functions such as the expression of drug metabolizing enzymes. High dose exposure to acetaminophen (APAP) induces hepatotoxicity because of the formation of reactive metabolites by CYP. Using fluorescence imaging, we observed that cell viability and glutathione levels were reduced in hepatocyte spheroids exposed to APAP mediated by the metabolic activation of CYP. On the other hand, there are species differences in the expression of drug metabolizing enzymes and metabolite profiles between animals and humans. Therefore, chimeric mice transfected with human hepatocytes were used for the in vivo assessment of metabolic profiles in humans. We found that drug metabolism and pharmacokinetics mediated by CYP and non-CYP enzymes, such as UDP-glucuronosyltransferase and aldehyde oxidase, in chimeric mice with humanized liver were similar to those in humans. The combination of in vitro and in vivo assessments using spheroids and chimeric mice with humanized liver, respectively, during the screening of drug candidates may help to reveal hepatotoxicity induced by the formation of metabolites. PMID:26521876

  14. [New drugs--chemical, pharmacological, metabolical, analytical and legal aspects].

    PubMed

    Ewald, Andreas H

    2015-03-01

    The characterisation of new psychoactive drugs which were identified in the last years in continuously increasing numbers is a challenge for different academic institutions. This paper gives an overview on new psychoactive drugs in regard of their chemistry, pharmacology, metabolism, analytics and legal aspects in Germany.

  15. The role of metabolic biomarkers in drug toxicity studies.

    PubMed

    Schnackenberg, Laura K; Beger, Richard D

    2008-01-01

    ABSTRACT Metabolic profiling is a technique that can potentially provide more sensitive and specific biomarkers of toxicity than the current clinical measures benefiting preclinical and clinical drug studies. Both nuclear magnetic resonance (NMR) and mass spectrometry (MS) platforms have been used for metabolic profiling studies of drug toxicity. Not only can both techniques provide novel biomarker(s) of toxicity but the combination of both techniques gives a broader range of metabolites evaluated. Changes in metabolic patterns can provide insight into mechanism(s) of toxicity and help to eliminate a potentially toxic new chemical entity earlier in the developmental process. Metabolic profiling offers numerous advantages in toxicological research and screening as sample collection and preparation are relatively simple. Further, sample throughput, reproducibility, and accuracy are high. The area of drug toxicity of therapeutic compounds has already been impacted by metabolic profiling studies and will continue to be impacted as new, more specific biomarker(s) are found. In order for a biomarker or pattern of biomarkers to be accepted, it must be shown that they originate from the target tissue of interest. Metabolic profiling studies are amenable to any biofluid or tissue sample making it possible to link the changes noted in urine for instance as originating from renal injury. Additionally, the ease of sample collection makes it possible to follow a single animal or subject over time in order to determine whether and when the toxicity resolves itself. This review focuses on the advantages of metabolic profiling for drug toxicity studies.

  16. Captan impairs CYP-catalyzed drug metabolism in the mouse.

    PubMed

    Paolini, M; Barillari, J; Trespidi, S; Valgimigli, L; Pedulli, G F; Cantelli-Forti, G

    1999-11-30

    To investigate whether the fungicide captan impairs CYP-catalyzed drug metabolism in murine liver, kidney and lung, the modulation of the regio- and stereo-selective hydroxylation of testosterone, including 6beta-(CYP3A), 6alpha-(CYP2A1 and CYP2B1) and 16alpha-(CYP2B9) oxidations was studied. Specific substrates as probes for different CYP isoforms such as p-nitrophenol (CYP2E1), pentoxyresorufin (CYP2B1), ethoxyresorufin (CYP1A1), aminopyrine (CYP3A), phenacetin and methoxyresorufin (CYP1A2), and ethoxycoumarin (mixed) were also considered. Daily doses of captan (7.5 or 15 mg/kg b.w., i.p.) were administered to different groups of Swiss Albino CD1 mice of both sexes for 1 or 3 consecutive days. While a single dose of this fungicide did not affect CYP-machinery, repeated treatment significantly impaired the microsomal metabolism; in the liver, for example, a general inactivating effect was observed, with the sole exception of testosterone 2alpha-hydroxylase activity which was induced up to 8.6-fold in males. In vitro studies showed that the mechanism-based inhibition was related to captan metabolites rather than the parental compound. In the kidney, both CYP3A- and CYP1A2-linked monooxygenases were significantly induced (2-fold) by this pesticide. Accelerated phenacetin and methoxyresorufin metabolism (CYP1A2) was also observed in the lung. Data on CYP3A (kidney) and CYP1A2 (kidney and lung) induction were corroborated by Western immunoblotting using rabbit polyclonal anti-CYP3A1/2 and CYP1A1/2 antibodies. By means of electron spin resonance (EPR) spectrometry coupled to a spin-trapping technique, it was found that the recorded induction generates a large amounts of the anion radical superoxide (O*2-) either in kidney or lung microsomes. These findings suggest that alterations in CYP-associated activities by captan exposure may result in impaired (endogenous) metabolism as well as of coadministered drugs with significant implications for their disposition. The

  17. Clinically Relevant Genetic Variations in Drug Metabolizing Enzymes

    PubMed Central

    Pinto, Navin; Dolan, M. Eileen

    2011-01-01

    In the field of pharmacogenetics, we currently have a few markers to guide physicians as to the best course of therapy for patients. For the most part, these genetic variants are within a drug metabolizing enzyme that has a large effect on the degree or rate at which a drug is converted to its metabolites. For many drugs, response and toxicity are multi-genic traits and understanding relationships between a patient's genetic variation in drug metabolizing enzymes and the efficacy and/or toxicity of a medication offers the potential to optimize therapies. This review will focus on variants in drug metabolizing enzymes with predictable and relatively large impacts on drug efficacy and/or toxicity; some of these drug/gene variant pairs have impacted drug labels by the United States Food and Drug Administration. The challenges in identifying genetic markers and implementing clinical changes based on known markers will be discussed. In addition, the impact of next generation sequencing in identifying rare variants will be addressed. PMID:21453273

  18. Against Their Wills: Children Born Affected by Drugs.

    ERIC Educational Resources Information Center

    Hodgkinson, Harold L.; Outtz, Janice Hamilton

    There is no national policy on assisting drug-using pregnant mothers nor on the children they produce. This paper looks at the issue of "crack-cocaine" and mothers who give birth to children after using drugs during pregnancy. It attempts to lay out what is known, and it puts forth "best guesses" regarding helping children born affected by drugs.…

  19. Environmental factors affecting pregnancy: endocrine disrupters, nutrients and metabolic pathways.

    PubMed

    Bazer, Fuller W; Wu, Guoyao; Johnson, Gregory A; Wang, Xiaoqiu

    2014-12-01

    Uterine adenogenesis, a unique post-natal event in mammals, is vulnerable to endocrine disruption by estrogens and progestins resulting in infertility or reduced prolificacy. The absence of uterine glands results in insufficient transport of nutrients into the uterine lumen to support conceptus development. Arginine, a component of histotroph, is substrate for production of nitric oxide, polyamines and agmatine and, with secreted phosphoprotein 1, it affects cytoskeletal organization of trophectoderm. Arginine is critical for development of the conceptus, pregnancy recognition signaling, implantation and placentation. Conceptuses of ungulates and cetaceans convert glucose to fructose which is metabolized via multiple pathways to support growth and development. However, high fructose corn syrup in soft drinks and foods may increase risks for metabolic disorders and increase insulin resistance in adults. Understanding endocrine disrupters and dietary substances, and novel pathways for nutrient metabolism during pregnancy can improve survival and growth, and prevent chronic metabolic diseases in offspring. PMID:25224489

  20. How does cancer cell metabolism affect tumor migration and invasion?

    PubMed

    Han, Tianyu; Kang, De; Ji, Daokun; Wang, Xiaoyu; Zhan, Weihua; Fu, Minggui; Xin, Hong-Bo; Wang, Jian-Bin

    2013-01-01

    Cancer metastasis is the major cause of cancer-associated death. Accordingly, identification of the regulatory mechanisms that control whether or not tumor cells become "directed walkers" is a crucial issue of cancer research. The deregulation of cell migration during cancer progression determines the capacity of tumor cells to escape from the primary tumors and invade adjacent tissues to finally form metastases. The ability to switch from a predominantly oxidative metabolism to glycolysis and the production of lactate even when oxygen is plentiful is a key characteristic of cancer cells. This metabolic switch, known as the Warburg effect, was first described in 1920s, and affected not only tumor cell growth but also tumor cell migration. In this review, we will focus on the recent studies on how cancer cell metabolism affects tumor cell migration and invasion. Understanding the new aspects on molecular mechanisms and signaling pathways controlling tumor cell migration is critical for development of therapeutic strategies for cancer patients.

  1. Rewired Metabolism in Drug-resistant Leukemia Cells

    PubMed Central

    Stäubert, Claudia; Bhuiyan, Hasanuzzaman; Lindahl, Anna; Broom, Oliver Jay; Zhu, Yafeng; Islam, Saiful; Linnarsson, Sten; Lehtiö, Janne; Nordström, Anders

    2015-01-01

    Cancer cells that escape induction therapy are a major cause of relapse. Understanding metabolic alterations associated with drug resistance opens up unexplored opportunities for the development of new therapeutic strategies. Here, we applied a broad spectrum of technologies including RNA sequencing, global untargeted metabolomics, and stable isotope labeling mass spectrometry to identify metabolic changes in P-glycoprotein overexpressing T-cell acute lymphoblastic leukemia (ALL) cells, which escaped a therapeutically relevant daunorubicin treatment. We show that compared with sensitive ALL cells, resistant leukemia cells possess a fundamentally rewired central metabolism characterized by reduced dependence on glutamine despite a lack of expression of glutamate-ammonia ligase (GLUL), a higher demand for glucose and an altered rate of fatty acid β-oxidation, accompanied by a decreased pantothenic acid uptake capacity. We experimentally validate our findings by selectively targeting components of this metabolic switch, using approved drugs and starvation approaches followed by cell viability analyses in both the ALL cells and in an acute myeloid leukemia (AML) sensitive/resistant cell line pair. We demonstrate how comparative metabolomics and RNA expression profiling of drug-sensitive and -resistant cells expose targetable metabolic changes and potential resistance markers. Our results show that drug resistance is associated with significant metabolic costs in cancer cells, which could be exploited using new therapeutic strategies. PMID:25697355

  2. Present and future in vitro approaches for drug metabolism.

    PubMed

    Ekins, S; Ring, B J; Grace, J; McRobie-Belle, D J; Wrighton, S A

    2000-01-01

    The 1980s through 1990s witnessed the widespread incorporation of in vitro absorption, distribution, metabolism, and excretion (ADME) approaches into drug development by drug companies. This has been exemplified by the integration of the basic science of cytochrome P450s (CYPs) into most drug metabolism departments so that information on the metabolic pathways of drugs and drug-drug interactions (DDIs) is no longer an academic exercise, but essential for regulatory submission. This has come about due to the application of a variety of new technologies and in vitro models. For example, subcellular fractions have been widely used in metabolism studies since the 1960s. The last two decades has seen the increased use of hepatocytes as the reproducibility of cell isolations improved. The 1990s saw the rejuvenation of liver slices (as new slicers were developed) and the utilization of cDNA expressed enzymes as these technologies matured. In addition, there has been considerable interest in extrapolating in vitro data to in vivo for parameters such as absorption, clearance and DDIs. The current philosophy of drug development is moving to a 'fail early--fail cheaply' paradigm. Therefore, in vitro ADME approaches are being applied to drug candidates earlier in development since they are essential for identifying compounds likely to present ADME challenges in the latter stages of drug development. These in vitro tools are also being used earlier in lead optimization biology, in parallel with approaches for optimizing target structure activity relationships, as well as identification of DDI and the involvement of metabolic pathways that demonstrate genetic polymorphisms. This would suggest that the line between discovery and development drug metabolism has blurred. In vitro approaches to ADME are increasingly being linked with high-throughput automation and analysis. Further, if we think of perhaps the fastest available way to screen for successful drugs with optimal ADME

  3. 77 FR 49447 - Endocrinologic and Metabolic Drugs Advisory Committee; Notice of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-16

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Endocrinologic and Metabolic Drugs Advisory Committee... be open to the public. Name of Committee: Endocrinologic and Metabolic Drugs Advisory...

  4. 78 FR 50423 - Endocrinologic and Metabolic Drugs Advisory Committee; Notice of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-19

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Endocrinologic and Metabolic Drugs Advisory Committee... be open to the public. Name of Committee: Endocrinologic and Metabolic Drugs Advisory...

  5. 77 FR 63840 - Endocrinologic and Metabolic Drugs Advisory Committee; Notice of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-17

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Endocrinologic and Metabolic Drugs Advisory Committee... be open to the public. Name of Committee: Endocrinologic and Metabolic Drugs Advisory...

  6. 77 FR 6567 - Endocrinologic and Metabolic Drugs Advisory Committee; Notice of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Endocrinologic and Metabolic Drugs Advisory Committee... be open to the public. Name of Committee: Endocrinologic and Metabolic Drugs Advisory...

  7. Genetic Alterations Affecting Cholesterol Metabolism and Human Fertility1

    PubMed Central

    DeAngelis, Anthony M.; Roy-O'Reilly, Meaghan; Rodriguez, Annabelle

    2014-01-01

    ABSTRACT Single nucleotide polymorphisms (SNPs) represent genetic variations among individuals in a population. In medicine, these small variations in the DNA sequence may significantly impact an individual's response to certain drugs or influence the risk of developing certain diseases. In the field of reproductive medicine, a significant amount of research has been devoted to identifying polymorphisms which may impact steroidogenesis and fertility. This review discusses current understanding of the effects of genetic variations in cholesterol metabolic pathways on human fertility that bridge novel linkages between cholesterol metabolism and reproductive health. For example, the role of the low-density lipoprotein receptor (LDLR) in cellular metabolism and human reproduction has been well studied, whereas there is now an emerging body of research on the role of the high-density lipoprotein (HDL) receptor scavenger receptor class B type I (SR-BI) in human lipid metabolism and female reproduction. Identifying and understanding how polymorphisms in the SCARB1 gene or other genes related to lipid metabolism impact human physiology is essential and will play a major role in the development of personalized medicine for improved diagnosis and treatment of infertility. PMID:25122065

  8. Abnormal folate metabolism in foetuses affected by neural tube defects.

    PubMed

    Dunlevy, Louisa P E; Chitty, Lyn S; Burren, Katie A; Doudney, Kit; Stojilkovic-Mikic, Taita; Stanier, Philip; Scott, Rosemary; Copp, Andrew J; Greene, Nicholas D E

    2007-04-01

    Folic acid supplementation can prevent many cases of neural tube defects (NTDs), whereas suboptimal maternal folate status is a risk factor, suggesting that folate metabolism is a key determinant of susceptibility to NTDs. Despite extensive genetic analysis of folate cycle enzymes, and quantification of metabolites in maternal blood, neither the protective mechanism nor the relationship between maternal folate status and susceptibility are understood in most cases. In order to investigate potential abnormalities in folate metabolism in the embryo itself, we derived primary fibroblastic cell lines from foetuses affected by NTDs and subjected them to the dU suppression test, a sensitive metabolic test of folate metabolism. Significantly, a subset of NTD cases exhibited low scores in this test, indicative of abnormalities in folate cycling that may be causally linked to the defect. Susceptibility to NTDs may be increased by suppression of the methylation cycle, which is interlinked with the folate cycle. However, reduced efficacy in the dU suppression test was not associated with altered abundance of the methylation cycle intermediates, s-adenosylmethionine and s-adenosylhomocysteine, suggesting that a methylation cycle defect is unlikely to be responsible for the observed abnormality of folate metabolism. Genotyping of samples for known polymorphisms in genes encoding folate-associated enzymes did not reveal any correlation between specific genotypes and the observed abnormalities in folate metabolism. These data suggest that as yet unrecognized genetic variants result in embryonic abnormalities of folate cycling that may be causally related to NTDs. PMID:17438019

  9. Contribution of environmental factors to variability in human drug metabolism.

    PubMed

    Dollery, C T; Fraser, H S; Mucklow, J C; Bulpitt, C J

    1979-01-01

    Drug metabolism in 96 London factory and office workers has been studied after simultaneous single doses of antipyrine (phenazone) and paracetamol (acetaminophen). Metabolic clearance of both drugs was significantly greater in subjects eating meat more than once a week than in those who ate meat less frequently. The precise contribution of diet could not be clearly defined since 90% of "meat-eaters" were European while all except one of the "vegetarians" were Asian. Clearance of both drugs increased with both alcohol and cigarette consumption. Regular intake of coffee and/or tea had a similar effect but, in the case of paracetamol, this did not attain statistical significance. Antipyrine clearance was lower among women who took the oral contraceptive pill than among those who did not, while paracetamol clearance was not significantly different. These findings may have implications for the use of drugs which are administered regularly in order to achieve steady-state plasma and tissue concentrations.

  10. [Drug-related disorders of water and electrolyte metabolism].

    PubMed

    Dendorfer, U; Mann, J

    2006-11-01

    Pharmacologic treatment may lead to diverse disturbances of water and electrolyte metabolism as adverse drug events. Diuretics are particularly likely to cause these complications typically including volume depletion, metabolic alkalosis, hyponatremia, and hypokalemia. Salt and water retention with edema formation is most frequently elicited by antihypertensives, steroid hormones, and nonsteroidal anti-inflammatory drugs. Drug-induced disorders of Na+ concentration may usually be attributed to altered antidiuretic hormone (ADH) effects, either as diabetes insipidus or as the syndrome of inappropriate ADH secretion. With hyper- and hypokalemia, redistribution between intra- and extracellular fluid as well as renal excretion play a role. Strategies to prevent these adverse drug reactions include careful consideration of risk factors and clinical and laboratory controls in the course of treatment.

  11. How Do Beta Blocker Drugs Affect Exercise?

    MedlinePlus

    ... American Heart area Search by State SELECT YOUR LANGUAGE Español (Spanish) 简体中文 (Traditional Chinese) 繁体中文 (Simplified Chinese) ... used because beta blockers affect everyone differently. The second way to monitor your intensity is simpler: making ...

  12. Oxidative hemoglobin reactions: Applications to drug metabolism.

    PubMed

    Spolitak, Tatyana; Hollenberg, Paul F; Ballou, David P

    2016-06-15

    Hb is a protein with multiple functions, acting as an O2 transport protein, and having peroxidase and oxidase activities with xenobiotics that lead to substrate radicals. However, there is a lack of evidence for intermediates involved in these reactions of Hb with redox-active compounds, including those with xenobiotics such as drugs, chemical carcinogens, and sulfides. In particular, questions exist as to what intermediates participate in reactions of either metHb or oxyHb with sulfides. The studies presented here elaborate kinetics and intermediates involved in the reactions of Hb with oxidants (H2O2 and mCPBA), and they demonstrate the formation of high valent intermediates, providing insights into mechanistic issues of sulfur and drug oxidations. Overall, we propose generalized mechanisms that include peroxidatic reactions using H2O2 generated from the autooxidation of oxyHb, with involvement of substrate radicals in reactions of Hb with oxidizable drugs such as metyrapone or 2,4-dinitrophenylhydrazine and with sulfides. We identify ferryl intermediates (with a Soret band at 407 nm) in oxidative reactions with all of the above-mentioned reactions. These spectral properties are consistent with a protonated ferryl heme, such as Cpd II or Cpd ES-like species (Spolitak et al., JIB, 2006, 100, 2034-2044). Mechanism(s) of Hb oxidative reactions are discussed.

  13. Regulation of drug-metabolizing enzymes by local and systemic liver injuries

    PubMed Central

    Guo, Yan; Hu, Bingfang; Xie, Yang; Billiar, Timothy R.; Sperry, Jason L.; Huang, Min; Xie, Wen

    2016-01-01

    Introduction Drug metabolism and disposition are critical in maintaining the chemical and functional homeostasis of xenobiotics/drugs and endobiotics. The liver plays an essential role in drug metabolism and disposition due to its abundant expression of drug-metabolizing enzymes (DMEs) and transporters. There is growing evidence to suggest that many hepatic and systemic diseases can affect drug metabolism and disposition by regulating the expression and/or activity of DMEs and transporters in the liver. Areas covered This review focuses on the recent progress on the regulation of DMEs by local and systemic liver injuries. Liver ischemia and reperfusion (I/R) and sepsis are used as examples of local and systemic injury, respectively. The reciprocal effect of the expression and activity of DMEs on animals' sensitivity to local and systemic liver injuries is also discussed. Expert opinion Local and systemic liver injuries have a major effect on the expression and activity of DMEs in the liver. Understanding the disease effect on DMEs is clinically important due to the concern of disease-drug interactions. Future studies are necessary to understand the mechanism by which liver injury regulates DMEs. Human studies are also urgently needed in order to determine whether the results in animals can be replicated in human patients. PMID:26751558

  14. Metabolic alterations in HIV-infected pregnant women: moving to metabolic tailoring of antiretroviral drugs.

    PubMed

    Guaraldi, Giovanni; Stentarelli, Chiara; Da Silva, Anarita Domingues; Luzi, Kety; Neri, Isabella; Cellini, Monica; Petrella, Elisabetta; Garlassi, Elisa; Menozzi, Marianna; Facchinetti, Fabio; Mussini, Cristina

    2014-01-01

    The most striking effect of increased survival and improved quality of life in HIV-infected women undergoing antiretroviral therapy is the feasibility of motherhood-desire satisfaction. However, such advantages are often associated with drug-related metabolic toxicities, particularly relevant in the pregnancy context. Recent guidelines provide recommendations and trends for the use of antiretroviral therapy in pregnant women, but current literature falls short of providing specific insights on the need for metabolic monitoring and treatment in HIV-infected pregnant women. In this review we provide specific insight into the state-of-the-art of: detection, evaluation, and management of metabolic alterations in this special population. Pregnancy is in fact a metabolic transition process, potentially associated with specific diseases in the mother, in the newborn, and in the adulthood of the child. We will not simply discuss antiretroviral therapy metabolic toxicities, but rather their interaction with the physiological metabolic changes occurring during pregnancy. Close monitoring is needed to diagnose metabolic alterations that can lead to adverse outcomes in the mother, in the newborn, and potentially in adulthood. Lifestyle interventions and an appropriate metabolic tailoring of antiretroviral therapy drugs need to be considered in the prevention and treatment of metabolic alteration during pregnancy.

  15. Cytochrome P450 genetic polymorphism in neonatal drug metabolism: role and practical consequences towards a new drug culture in neonatology.

    PubMed

    Fanni, D; Ambu, R; Gerosa, C; Nemolato, S; Castagnola, M; Van Eyken, P; Faa, G; Fanos, V

    2014-01-01

    The cytochrome P450 superfamily (CYP450) in humans is formed by 57 functional monooxygenases critical for the metabolism of numerous endogenous and exogenous compounds. The superfamily is organized into 18 families and 44 subfamilies. CYP nomenclature is based on the identity of amino acids. The most important functions of the CYP450 are related to metabolism of endogenous compounds, detoxification of exogenous xenobiotics and decomposition of the vast majority of currently used drugs. The expression of CYP450 enzymes in the human body is characterized by a marked substrate and tissue specificity, the most important being localized in the liver, but also present in kidney, lung, brain, breast, prostate and in the small intestine. The human cytochrome P450 3A gene family (CYP3A) accounts for the largest portion of CYP450 proteins in human liver and includes 4 genes: CYP3A4, CYP3A5, CYP3A7, CYP3A43. Multiple and complex genetic variations, marked interindividual, interethnic and gender variability have been reported regarding CYP3A isoform expression and activity. Multiple factors may affect CYP3A expression and activity, such as inducers like rifampicin, phenobarbital, 3-methylcholantrene, beta-naphtoflavone, and dexamethasone. The maturation of organ systems, paralleled by ontogeny of drug-metabolizing enzymes during fetal life and in the first months of postnatal life, surely exerts profound effects on drug disposition, probably being the predominant factor accounting for age-associated changes in drug clearance. In fact, drug dosage in the perinatal period represents a continuous challenge for neonatologists. The purpose of this article is to provide a brief review of the pharmacokinetic differences between neonates and adults, showing the peculiarities of liver CYP450-related drug metabolism in the perinatal period and at birth, and to report the toxic mechanisms of liver injury in neonates, due to the most frequently utilized drugs in NICU centers.

  16. Low-Turnover Drug Molecules: A Current Challenge for Drug Metabolism Scientists.

    PubMed

    Hutzler, J Matthew; Ring, Barbara J; Anderson, Shelby R

    2015-12-01

    In vitro assays using liver subcellular fractions or suspended hepatocytes for characterizing the metabolism of drug candidates play an integral role in the optimization strategy employed by medicinal chemists. However, conventional in vitro assays have limitations in their ability to predict clearance and generate metabolites for low-turnover (slowly metabolized) drug molecules. Due to a rapid loss in the activity of the drug-metabolizing enzymes, in vitro incubations are typically performed for a maximum of 1 hour with liver microsomes to 4 hours with suspended hepatocytes. Such incubations are insufficient to generate a robust metabolic response for compounds that are slowly metabolized. Thus, the challenge of accurately estimating low human clearance with confidence has emerged to be among the top challenges that drug metabolism scientists are confronted with today. In response, investigators have evaluated novel methodologies to extend incubation times and more sufficiently measure metabolism of low-turnover drugs. These methods include plated human hepatocytes in monoculture, and a novel in vitro methodology using a relay of sequential incubations with suspended cryopreserved hepatocytes. In addition, more complex in vitro cellular models, such as HepatoPac (Hepregen, Medford, MA), a micropatterned hepatocyte-fibroblast coculture system, and the HµREL (Beverley Hills, CA) hepatic coculture system, have been developed and characterized that demonstrate prolonged enzyme activity. In this review, the advantages and disadvantages of each of these in vitro methodologies as it relates to the prediction of clearance and metabolite identification will be described in an effort to provide drug metabolism scientists with the most up-to-date experimental options for dealing with the complex issue of low-turnover drug candidates. PMID:26363026

  17. Low-Turnover Drug Molecules: A Current Challenge for Drug Metabolism Scientists.

    PubMed

    Hutzler, J Matthew; Ring, Barbara J; Anderson, Shelby R

    2015-12-01

    In vitro assays using liver subcellular fractions or suspended hepatocytes for characterizing the metabolism of drug candidates play an integral role in the optimization strategy employed by medicinal chemists. However, conventional in vitro assays have limitations in their ability to predict clearance and generate metabolites for low-turnover (slowly metabolized) drug molecules. Due to a rapid loss in the activity of the drug-metabolizing enzymes, in vitro incubations are typically performed for a maximum of 1 hour with liver microsomes to 4 hours with suspended hepatocytes. Such incubations are insufficient to generate a robust metabolic response for compounds that are slowly metabolized. Thus, the challenge of accurately estimating low human clearance with confidence has emerged to be among the top challenges that drug metabolism scientists are confronted with today. In response, investigators have evaluated novel methodologies to extend incubation times and more sufficiently measure metabolism of low-turnover drugs. These methods include plated human hepatocytes in monoculture, and a novel in vitro methodology using a relay of sequential incubations with suspended cryopreserved hepatocytes. In addition, more complex in vitro cellular models, such as HepatoPac (Hepregen, Medford, MA), a micropatterned hepatocyte-fibroblast coculture system, and the HµREL (Beverley Hills, CA) hepatic coculture system, have been developed and characterized that demonstrate prolonged enzyme activity. In this review, the advantages and disadvantages of each of these in vitro methodologies as it relates to the prediction of clearance and metabolite identification will be described in an effort to provide drug metabolism scientists with the most up-to-date experimental options for dealing with the complex issue of low-turnover drug candidates.

  18. The Co-Metabolism within the Gut-Brain Metabolic Interaction: Potential Targets for Drug Treatment and Design.

    PubMed

    Obrenovich, Mark; Flückiger, Rudolf; Sykes, Lorraine; Donskey, Curtis

    2016-01-01

    We know that within the complex mammalian gut is any number of metabolic biomes. The gut has been sometimes called the "second brain" within the "gut-brain axis". A more informative term would be the gut-brain metabolic interactome, which is coined here to underscore the relationship between the digestive system and cognitive function or dysfunction as the case may be. Co-metabolism between the host and the intestinal microbiota is essential for life's processes. How diet, lifestyle, antibiotics and other factors shape the gut microbiome constitutes a rapidly growing area of research. Conversely, the gut microbiome also affects mammalian systems. Metabolites of the gut-brain axis are potential targets for treatment and drug design since the interaction or biochemical interplay results in net metabolite production or end-products with either positive or negative effects on human health. This review explores the gut-brain metabolic interactome, with particular emphasis on drug design and treatment strategies and how commensal bacteria or their disruption lead to dysbiosis and the effect this has on neurochemistry. Increasing data indicate that the intestinal microbiome can affect neurobiology, from mental and even behavioral health to memory, depression, mood, anxiety, obesity, cravings and even the creation and maintenance of the blood brain barrier.

  19. The Co-Metabolism within the Gut-Brain Metabolic Interaction: Potential Targets for Drug Treatment and Design.

    PubMed

    Obrenovich, Mark; Flückiger, Rudolf; Sykes, Lorraine; Donskey, Curtis

    2016-01-01

    We know that within the complex mammalian gut is any number of metabolic biomes. The gut has been sometimes called the "second brain" within the "gut-brain axis". A more informative term would be the gut-brain metabolic interactome, which is coined here to underscore the relationship between the digestive system and cognitive function or dysfunction as the case may be. Co-metabolism between the host and the intestinal microbiota is essential for life's processes. How diet, lifestyle, antibiotics and other factors shape the gut microbiome constitutes a rapidly growing area of research. Conversely, the gut microbiome also affects mammalian systems. Metabolites of the gut-brain axis are potential targets for treatment and drug design since the interaction or biochemical interplay results in net metabolite production or end-products with either positive or negative effects on human health. This review explores the gut-brain metabolic interactome, with particular emphasis on drug design and treatment strategies and how commensal bacteria or their disruption lead to dysbiosis and the effect this has on neurochemistry. Increasing data indicate that the intestinal microbiome can affect neurobiology, from mental and even behavioral health to memory, depression, mood, anxiety, obesity, cravings and even the creation and maintenance of the blood brain barrier. PMID:26831263

  20. Drug-induced liver injury: the role of drug metabolism and transport.

    PubMed

    Corsini, Alberto; Bortolini, Michele

    2013-05-01

    Many studies have pinpointed the significant contribution of liver-mediated drug metabolism and transport to the complexity of drug-induced liver injury (DILI). Phase I cytochrome P450 (CYP450) enzymes can lead to altered drug metabolism and formation of toxic metabolites, whilst Phase II enzymes are also associated with DILI. The emerging role of hepatic transporters in regulating the movement of endogenous and exogenous chemicals (e.g., bile acids and drugs) across cellular and tissue membranes is critical in determining the pathophysiology of liver disease as well as drug toxicity and efficacy. Genetic and environmental factors can have a significant impact on drug metabolism and transporter proteins, consequently increasing the risk of DILI in susceptible individuals. The assessment of these factors therefore represents an important approach for predicting and preventing DILI, by better understanding the pharmacological profile of a specific drug. This review focuses on the mechanisms of DILI associated with drug metabolism and hepatic transport, and how they can be influenced by underlying factors. PMID:23436293

  1. Energy Metabolism and Drug Efflux in Mycobacterium tuberculosis

    PubMed Central

    Black, Philippa A.; Warren, Robin M.; Louw, Gail E.; van Helden, Paul D.; Victor, Thomas C.

    2014-01-01

    The inherent drug susceptibility of microorganisms is determined by multiple factors, including growth state, the rate of drug diffusion into and out of the cell, and the intrinsic vulnerability of drug targets with regard to the corresponding antimicrobial agent. Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), remains a significant source of global morbidity and mortality, further exacerbated by its ability to readily evolve drug resistance. It is well accepted that drug resistance in M. tuberculosis is driven by the acquisition of chromosomal mutations in genes encoding drug targets/promoter regions; however, a comprehensive description of the molecular mechanisms that fuel drug resistance in the clinical setting is currently lacking. In this context, there is a growing body of evidence suggesting that active extrusion of drugs from the cell is critical for drug tolerance. M. tuberculosis encodes representatives of a diverse range of multidrug transporters, many of which are dependent on the proton motive force (PMF) or the availability of ATP. This suggests that energy metabolism and ATP production through the PMF, which is established by the electron transport chain (ETC), are critical in determining the drug susceptibility of M. tuberculosis. In this review, we detail advances in the study of the mycobacterial ETC and highlight drugs that target various components of the ETC. We provide an overview of some of the efflux pumps present in M. tuberculosis and their association, if any, with drug transport and concomitant effects on drug resistance. The implications of inhibiting drug extrusion, through the use of efflux pump inhibitors, are also discussed. PMID:24614376

  2. Factors That Affect Adolescent Drug Users' Suicide Attempts.

    PubMed

    Park, Subin; Song, Hokwang

    2016-05-01

    Drug abuse has been widely linked to suicide risk. We examined the factors that affect adolescent drug users' suicide attempts in South Korea. This study analyzed the data of 311 adolescents who had used drugs such as inhalants, psychotropic drugs, and marijuana (195 males and 116 females). Among 311 subjects, 109 (35.0%) had attempted suicide during the last 12 months. After adjusting for other variables, depressive mood (OR=19.79) and poly-drug use (OR=2.79), and low/middle levels of academic achievement compared with a high level (OR=3.72 and 4.38) were independently associated with increased odds of a suicide attempt, while better perceived health (OR=0.32) was independently associated with reduced odds of a suicide attempt. For adolescent drug users, preventive work should be directed toward the active treatment of drug use, depression, and physical health and reinforcing proper coping strategies for academic and other stress. PMID:27247604

  3. Factors That Affect Adolescent Drug Users' Suicide Attempts

    PubMed Central

    Song, Hokwang

    2016-01-01

    Drug abuse has been widely linked to suicide risk. We examined the factors that affect adolescent drug users' suicide attempts in South Korea. This study analyzed the data of 311 adolescents who had used drugs such as inhalants, psychotropic drugs, and marijuana (195 males and 116 females). Among 311 subjects, 109 (35.0%) had attempted suicide during the last 12 months. After adjusting for other variables, depressive mood (OR=19.79) and poly-drug use (OR=2.79), and low/middle levels of academic achievement compared with a high level (OR=3.72 and 4.38) were independently associated with increased odds of a suicide attempt, while better perceived health (OR=0.32) was independently associated with reduced odds of a suicide attempt. For adolescent drug users, preventive work should be directed toward the active treatment of drug use, depression, and physical health and reinforcing proper coping strategies for academic and other stress. PMID:27247604

  4. Absorption, distribution, metabolism and excretion pharmacogenomics of drugs of abuse.

    PubMed

    Meyer, Markus R; Maurer, Hans H

    2011-02-01

    Pharmacologic and toxic effects of xenobiotics, such as drugs of abuse, depend on the genotype and phenotype of an individual, and conversely on the isoenzymes involved in their metabolism and transport. The current knowledge of such isoenzymes of frequently abused therapeutics such as opioids (oxycodone, hydrocodone, methadone, fentanyl, buprenorphine, tramadol, heroin, morphine and codeine), anesthetics (γ-hydroxybutyric acid, propofol, ketamine and phencyclidine) and cognitive enhancers (methylphenidate and modafinil), and some important plant-derived hallucinogens (lysergide, salvinorin A, psilocybin and psilocin), as well as of nicotine in humans are summarized in this article. The isoenzymes (e.g., cytochrome P450, glucuronyltransferases, esterases and reductases) involved in the metabolism of drugs and some pharmacokinetic data are discussed. The relevance of such data is discussed for predicting possible interactions with other xenobiotics, understanding pharmacokinetic behavior and pharmacogenomic variations, assessing toxic risks, developing suitable toxicological analysis procedures, and finally for interpretating drug testing results.

  5. MicroRNAs as regulators of drug transporters, drug-metabolizing enzymes, and tight junctions: implication for intestinal barrier function.

    PubMed

    Ikemura, Kenji; Iwamoto, Takuya; Okuda, Masahiro

    2014-08-01

    Drug transporters, drug-metabolizing enzymes, and tight junctions in the small intestine function as an absorption barrier and sometimes as a facilitator of orally administered drugs. The expression of these proteins often fluctuates and thereby causes individual pharmacokinetic variability. MicroRNAs (miRNAs), which are small non-coding RNAs, have recently emerged as a new class of gene regulator. MiRNAs post-transcriptionally regulate gene expression by binding to target mRNA to suppress its translation or regulate its degradation. They have been shown to be key regulators of proteins associated with pharmacokinetics. Moreover, the role of miRNAs on the expression of some proteins expressed in the small intestine has recently been clarified. In this review, we summarize current knowledge regarding the role of miRNAs in the regulation of drug transporters, drug-metabolizing enzymes, and tight junctions as well as its implication for intestinal barrier function. MiRNAs play vital roles in the differentiation, architecture, and barrier function of intestinal epithelial cells, and directly and/or indirectly regulate the expression and function of proteins associated with drug absorption in intestinal epithelial cells. Moreover, the variation of miRNA expression caused by pathological and physiological conditions as well as genetic factors should affect the expression of these proteins. Therefore, miRNAs could be significant factors affecting inter- and intra-individual variations in the pharmacokinetics and intestinal absorption of drugs. Overall, miRNAs could be promising targets for personalized pharmacotherapy or other attractive therapies through intestinal absorption of drugs.

  6. Bile Acid Signaling in Metabolic Disease and Drug Therapy

    PubMed Central

    Li, Tiangang

    2014-01-01

    Bile acids are the end products of cholesterol catabolism. Hepatic bile acid synthesis accounts for a major fraction of daily cholesterol turnover in humans. Biliary secretion of bile acids generates bile flow and facilitates hepatobiliary secretion of lipids, lipophilic metabolites, and xenobiotics. In the intestine, bile acids are essential for the absorption, transport, and metabolism of dietary fats and lipid-soluble vitamins. Extensive research in the last 2 decades has unveiled new functions of bile acids as signaling molecules and metabolic integrators. The bile acid–activated nuclear receptors farnesoid X receptor, pregnane X receptor, constitutive androstane receptor, vitamin D receptor, and G protein–coupled bile acid receptor play critical roles in the regulation of lipid, glucose, and energy metabolism, inflammation, and drug metabolism and detoxification. Bile acid synthesis exhibits a strong diurnal rhythm, which is entrained by fasting and refeeding as well as nutrient status and plays an important role for maintaining metabolic homeostasis. Recent research revealed an interaction of liver bile acids and gut microbiota in the regulation of liver metabolism. Circadian disturbance and altered gut microbiota contribute to the pathogenesis of liver diseases, inflammatory bowel diseases, nonalcoholic fatty liver disease, diabetes, and obesity. Bile acids and their derivatives are potential therapeutic agents for treating metabolic diseases of the liver. PMID:25073467

  7. Chemoprotective activity of boldine: modulation of drug-metabolizing enzymes.

    PubMed

    Kubínová, R; Machala, M; Minksová, K; Neca, J; Suchý, V

    2001-03-01

    Possible chemoprotective effects of the naturally occurring alkaloid boldine, a major alkaloid of boldo (Peumus boldus Mol.) leaves and bark, including in vitro modulations of drug-metabolizing enzymes in mouse hepatoma Hepa-1 cell line and mouse hepatic microsomes, were investigated. Boldine manifested inhibition activity on hepatic microsomal CYP1A-dependent 7-ethoxyresorufin O-deethylase and CYP3A-dependent testosterone 6 beta-hydroxylase activities and stimulated glutathione S-transferase activity in Hepa-1 cells. In addition to the known antioxidant activity, boldine could decrease the metabolic activation of other xenobiotics including chemical mutagens. PMID:11265593

  8. Drug-Induced Hepatotoxicity: Metabolic, Genetic and Immunological Basis

    PubMed Central

    Njoku, Dolores B.

    2014-01-01

    Drug-induced hepatotoxicity is a significant cause of acute liver failure and is usually the primary reason that therapeutic drugs are removed from the commercial market. Multiple mechanisms can culminate in drug hepatotoxicity. Metabolism, genetics and immunology separately and in concert play distinct and overlapping roles in this process. This review will cover papers we feel have addressed these mechanisms of drug-induced hepatotoxicity in adults following the consumption of commonly used medications. The aim is to generate discussion around “trigger point” papers where the investigators generated new science or provided additional contribution to existing science. Hopefully these discussions will assist in uncovering key areas that need further attention. PMID:24758937

  9. SRC-3 is required for CAR-regulated hepatocyte proliferation and drug metabolism

    PubMed Central

    Chen, Tenghui; Chen, Qiang; Xu, Yixiang; Zhou, Qiling; Zhu, Jingwei; Zhang, Hao; Wu, Qiao; Xu, Jianming; Yu, Chundong

    2011-01-01

    Background & Aims Nuclear receptors such as pregnane X receptor and constitutive androstane receptor (CAR) are important regulators of drug-metabolizing systems such as P450s enzymes and modulate xenobiotic metabolism as well as hepatocellular proliferation. Binding of CAR to NR response elements alone is not sufficient to activate gene expression. Here we investigate the role of steroid receptor coactivator (SRC) family members in CAR-mediated hepatocyte proliferation and drug metabolism. Methods The role of SRCs in CAR activation was assessed in cell-based transfection assays and protein-protein interaction assays. The in vivo role of SRCs in CAR-mediated hepatocyte proliferation and drug metabolism was examined by using mice deficient in SRCs. Results SRC-3 displayed the highest coactivating activity to CAR compared with SRC-1 and SRC-2 in a cell-based reporter assay. Knockout of SRC-3 in mice attenuated hepatic hyperplasia induced by a CAR agonist 1,4-bis-[2-(3,5-dichloropyridyloxy)] benzene (TCPOBOP), which was associated with a reduced expression of c-Myc and Foxm-1. In contrast, knockout of SRC-1 or SRC-2 in mice did not affect TCPOBOP-induced hepatic hyperplasia. SRC-3-deficient mice were hypersensitive to zoxazolamine-induced paralysis, but were resistant to acetaminophen hepatotoxicity induced by TCPOBOP, whereas mutant mice deficient in SRC-1 or SRC-2 exhibited severe acetaminophen hepatotoxicity similar to wild-type controls. Accordingly, deficiency in SRC-3, but not SRC-1 or SRC-2, resulted in a reduced CAR-mediated expression of drug metabolism-related genes in the liver. Conclusions Our study demonstrates that SRC-3 is the predominant transcriptional coactivator among the three SRC family members for CAR activation to promote hepatocyte proliferation and drug metabolism. PMID:21827731

  10. Short-term fasting alters cytochrome P450-mediated drug metabolism in humans.

    PubMed

    Lammers, Laureen A; Achterbergh, Roos; de Vries, Emmely M; van Nierop, F Samuel; Klümpen, Heinz-Josef; Soeters, Maarten R; Boelen, Anita; Romijn, Johannes A; Mathôt, Ron A A

    2015-06-01

    Experimental studies indicate that short-term fasting alters drug metabolism. However, the effects of short-term fasting on drug metabolism in humans need further investigation. Therefore, the aim of this study was to evaluate the effects of short-term fasting (36 h) on P450-mediated drug metabolism. In a randomized crossover study design, nine healthy subjects ingested a cocktail consisting of five P450-specific probe drugs [caffeine (CYP1A2), S-warfarin (CYP2C9), omeprazole (CYP2C19), metoprolol (CYP2D6), and midazolam (CYP3A4)] on two occasions (control study after an overnight fast and after 36 h of fasting). Blood samples were drawn for pharmacokinetic analysis using nonlinear mixed effects modeling. In addition, we studied in Wistar rats the effects of short-term fasting on hepatic mRNA expression of P450 isoforms corresponding with the five studied P450 enzymes in humans. In the healthy subjects, short-term fasting increased oral caffeine clearance by 20% (P = 0.03) and decreased oral S-warfarin clearance by 25% (P < 0.001). In rats, short-term fasting increased mRNA expression of the orthologs of human CYP1A2, CYP2C19, CYP2D6, and CYP3A4 (P < 0.05), and decreased the mRNA expression of the ortholog of CYP2C9 (P < 0.001) compared with the postabsorptive state. These results demonstrate that short-term fasting alters cytochrome P450-mediated drug metabolism in a nonuniform pattern. Therefore, short-term fasting is another factor affecting cytochrome P450-mediated drug metabolism in humans.

  11. Fermentation and Hydrogen Metabolism Affect Uranium Reduction by Clostridia

    DOE PAGES

    Gao, Weimin; Francis, Arokiasamy J.

    2013-01-01

    Previously, it has been shown that not only is uranium reduction under fermentation condition common among clostridia species, but also the strains differed in the extent of their capability and the pH of the culture significantly affected uranium(VI) reduction. In this study, using HPLC and GC techniques, metabolic properties of those clostridial strains active in uranium reduction under fermentation conditions have been characterized and their effects on capability variance of uranium reduction discussed. Then, the relationship between hydrogen metabolism and uranium reduction has been further explored and the important role played by hydrogenase in uranium(VI) and iron(III) reduction bymore » clostridia demonstrated. When hydrogen was provided as the headspace gas, uranium(VI) reduction occurred in the presence of whole cells of clostridia. This is in contrast to that of nitrogen as the headspace gas. Without clostridia cells, hydrogen alone could not result in uranium(VI) reduction. In alignment with this observation, it was also found that either copper(II) addition or iron depletion in the medium could compromise uranium reduction by clostridia. In the end, a comprehensive model was proposed to explain uranium reduction by clostridia and its relationship to the overall metabolism especially hydrogen (H 2 ) production.« less

  12. Fermentation and Hydrogen Metabolism Affect Uranium Reduction by Clostridia

    SciTech Connect

    Gao, Weimin; Francis, Arokiasamy J.

    2013-01-01

    Previously, it has been shown that not only is uranium reduction under fermentation condition common among clostridia species, but also the strains differed in the extent of their capability and the pH of the culture significantly affected uranium(VI) reduction. In this study, using HPLC and GC techniques, metabolic properties of those clostridial strains active in uranium reduction under fermentation conditions have been characterized and their effects on capability variance of uranium reduction discussed. Then, the relationship between hydrogen metabolism and uranium reduction has been further explored and the important role played by hydrogenase in uranium(VI) and iron(III) reduction by clostridia demonstrated. When hydrogen was provided as the headspace gas, uranium(VI) reduction occurred in the presence of whole cells of clostridia. This is in contrast to that of nitrogen as the headspace gas. Without clostridia cells, hydrogen alone could not result in uranium(VI) reduction. In alignment with this observation, it was also found that either copper(II) addition or iron depletion in the medium could compromise uranium reduction by clostridia. In the end, a comprehensive model was proposed to explain uranium reduction by clostridia and its relationship to the overall metabolism especially hydrogen (H2) production.

  13. Approaches for minimizing metabolic activation of new drug candidates in drug discovery.

    PubMed

    Kumar, Sanjeev; Mitra, Kaushik; Kassahun, Kelem; Baillie, Thomas A

    2010-01-01

    A large body of circumstantial evidence suggests that metabolic activation of drug candidates to chemically reactive electrophilic metabolites that are capable of covalently modifying cellular macromolecules may result in acute and/or immune system-mediated idiosyncratic toxicities in humans. Thus, minimizing the potential for metabolic activation of new drug candidates during the drug discovery and lead optimization stage represents a prudent strategy to help discover and develop the next generation of safe and effective therapeutic agents. In the present chapter, we discuss the scientific methodologies that currently are available to industrial pharmaceutical scientists for assessing and minimizing metabolic activation during drug discovery, their attributes and limitations, and future scientific directions that have the potential to help advance progress in this field. We also propose a roadmap that should help utilize the armamentarium of available scientific tools in a logical way and contribute to addressing metabolic activation issues in the drug discovery-setting in a rapid, scientifically appropriate, and resource-conscious manner.

  14. Factors affecting antipyrine metabolism in West African villagers.

    PubMed

    Fraser, H S; Bulpitt, C J; Kahn, C; Mould, G; Mucklow, J C; Dollery, C T

    1976-09-01

    Saliva half-life of antipyrine was studied in 49 healthy Gambians between 20 and 60 yr of age of whom 27 were male (mean age, 44.5) and 22 female (mean age, 39.1). Body wieght, height, ponderal index, albumin, and hemoglobin were moderately reduced compared to accepted normal values. Antipyrine half-life was 13.6 +/- 0.58 (SEM) hr. Multiple regression analysis showed that sex, cola nut consumption, hemoglobin in women, and height in men were statiscally significant independent predictors of antipyrine half-life. Half-life was shorter in women, decreased with an increase in height in men, and was prolonged by cola nut consumption. Half-life in women increased with hemoglobin. These factors explained 36% of the variation and suggest that geographic differences in the environment could be important in drug metabolism in man. PMID:954356

  15. Use of immobilized enzymes in drug metabolism studies.

    PubMed

    Dulik, D M; Fenselau, C

    1988-04-01

    The immobilization of drug-metabolizing enzymes onto polymeric supports offers several advantages over use of conventional microsomal or soluble enzyme preparations. These include increased storage stability, facilitated separation of products from the incubation mixture, the ability to recover and reuse the enzyme catalyst, and in many cases, stabilization of the tertiary structure of membrane-bound enzymes. Attachment of the protein to the solid support may be accomplished by adsorption, covalent bonding, or entrapment techniques. This methodology has been successfully utilized for studies with such enzymes as cytochrome P-450, UDP-glucuronyltransferases, glutathione S-transferases, S-methyltransferases, and N-acetyltransferases. Although often employed for the synthesis of xenobiotic metabolites, immobilized enzymes have been used for mechanistic and relative reactivity studies, limited kinetic studies, and extracorporeal detoxification. Co-immobilization of multiple drug-metabolizing enzyme systems has made possible the sequential formation of metabolites arising from oxidation followed by conjugation. Immobilized enzymes may also be used in the prediction of species-dependent metabolic pathways. The potential for large-scale synthesis of drug metabolites using this methodology has been explored. PMID:3127263

  16. Interactions between dietary boron and thiamine affect lipid metabolism

    SciTech Connect

    Herbel, J.L.; Hunt, C.D. )

    1991-03-15

    An experiment was designed to test the hypothesis that dietary boron impacts upon the function of various coenzymes involved in energy metabolism. In a 2 {times} 7 factorially-arranged experiment, weanling, vitamin D{sub 3}-deprived rats were fed a ground corn-casein-corn oil based diet supplemented with 0 or 2 mg boron/kg and 50% of the requirement for thiamine (TM), riboflavin (RF), pantothenic acid (PA) or pyridoxine (PX); 0% for folic acid (FA) or nicotinic acid (NA). All vitamins were supplemented in adequate amounts in the control diet. At 8 weeks of age, the TM dietary treatment was the one most affected by supplemental dietary boron (SDB). In rats that were fed 50% TM, SDB increased plasma concentrations of triglyceride (TG) and activity of alanine transaminase (ALT), and the liver to body weight (L/B) ratio. However, in the SDB animals, adequate amounts of TM decreased the means of those variables to near that observed in non-SDB rats fed 50% TM. The findings suggest that an interaction between dietary boron and TM affects lipid metabolism.

  17. Boron nutrition affects the carbon metabolism of silver birch seedlings.

    PubMed

    Ruuhola, Teija; Keinänen, Markku; Keski-Saari, Sarita; Lehto, Tarja

    2011-11-01

    Boron (B) is an essential micronutrient whose deficiency is common both in agriculture and in silviculture. Boron deficiency impairs the growth of plants and affects many metabolic processes like carbohydrate metabolism. Boron deficiency and also excess B may decrease the sink demand by decreasing the growth and sugar transport which may lead to the accumulation of carbohydrates and down-regulation of photosynthesis. In this study, we investigated the effects of B nutrition on the soluble and storage carbohydrate concentrations of summer leaves and autumn buds in a deciduous tree species, Betula pendula Roth. In addition, we investigated the changes in the pools of condensed tannins between summer and autumn harvests. One-year-old birch seedlings were fertilized with a complete nutrient solution containing three different levels of B: 0, 30 and 100% of the standard level for complete nutrient solution. Half of the seedlings were harvested after summer period and another half when leaves abscised. The highest B fertilization level (B100) caused an accumulation of starch and a decrease in the concentrations of hexoses (glucose and fructose) in summer leaves, whereas in the B0 seedlings, hexoses (mainly glucose) accumulated and starch decreased. These changes in carbohydrate concentrations might be related to the changes in the sink demand since the autumn growth was the smallest for the B100 seedlings and largest for the B30 seedlings that did not accumulate carbohydrates. The autumn buds of B30 seedlings contained the lowest levels of glucose, glycerol, raffinose and total polyols, which was probably due to the dilution effect of the deposition of other substances like phenols. Condensed tannins accumulated in high amounts in the birch stems during the hardening of seedlings and the largest accumulation was detected in the B30 treatment. Our results suggest that B nutrition of birch seedlings affects the carbohydrate and phenol metabolism and may play an important

  18. Drug metabolism and pharmacokinetic diversity of ranunculaceae medicinal compounds.

    PubMed

    Hao, Da-Cheng; Ge, Guang-Bo; Xiao, Pei-Gen; Wang, Ping; Yang, Ling

    2015-01-01

    The wide-reaching distributed angiosperm family Ranunculaceae has approximately 2200 species in around 60 genera. Chemical components of this family include several representative groups: benzylisoquinoline alkaloid (BIA), ranunculin, triterpenoid saponin and diterpene alkaloid, etc. Their extensive clinical utility has been validated by traditional uses of thousands of years and current evidence-based medicine studies. Drug metabolism and pharmacokinetic (DMPK) studies of plant-based natural products are an indispensable part of comprehensive medicinal plant exploration, which could facilitate conservation and sustainable utilization of Ranunculaceae pharmaceutical resources, as well as new chemical entity development with improved DMPK parameters. However, DMPK characteristics of Ranunculaceaederived medicinal compounds have not been summarized. Black cohosh (Cimicifuga) and goldenseal (Hydrastis) raise concerns of herbdrug interaction. DMPK studies of other Ranunculaceae genera, e.g., Nigella, Delphinium, Aconitum, Trollius, and Coptis, are also rapidly increasing and becoming more and more clinically relevant. In this contribution, we highlight the up-to-date awareness, as well as the challenges around the DMPK-related issues in optimization of drug development and clinical practice of Ranunculaceae compounds. Herb-herb interaction of Ranunculaceae herb-containing traditional Chinese medicine (TCM) formula could significantly influence the in vivo pharmacokinetic behavior of compounds thereof, which may partially explain the complicated therapeutic mechanism of TCM formula. Although progress has been made on revealing the absorption, distribution, metabolism, excretion and toxicity (ADME/T) of Ranunculaceae compounds, there is a lack of DMPK studies of traditional medicinal genera Aquilegia, Thalictrum and Clematis. Fluorescent probe compounds could be promising substrate, inhibitor and/or inducer in future DMPK studies of Ranunculaceae compounds. A better

  19. Enzyme kinetics in drug metabolism: fundamentals and applications.

    PubMed

    Nagar, Swati; Argikar, Upendra A; Tweedie, Donald J

    2014-01-01

    Enzymes are protein catalysts that lower the energy barrier for a reaction and speed the rate of a chemical change. The kinetics of reactions catalyzed by enzymes, as well as several mechanisms underlying the kinetics, have been comprehensively studied and written in textbooks (1, 2). The importance of quantitative evaluation of enzymatic processes has been recognized in many fields of study, including biochemistry, molecular biology, and pharmaceutical sciences to name a few. In pharmaceutical sciences, the applications of enzyme kinetics range from hit finding efforts for new chemical entities on a pharmacological target to concentration effect relationships to large-scale biosynthesis. The study of the science of drug metabolism has two principal concepts-rate and extent. While understanding disposition pathways and identification of metabolites provides an insight into the extent of metabolism, kinetics of depletion of substrates (endogenous or exogenous) and formation of metabolites deals with the rate of metabolism. The current textbook specifically focuses on kinetics of drug-metabolizing enzymes, detailing specific enzyme classes, and discusses kinetics as they apply to drug transporters. This textbook also outlines additional factors that contribute to the kinetics of reactions catalyzed by these proteins such as variability in isoforms (pharmacogenomics) and experimental factors including key concepts such as alterations of substrate concentrations due to binding. Applications of these approaches in predicting kinetic parameters and alternative approaches for enzymes (systems biology) and transporters are also discussed. The final section focuses on real-life examples (case studies) to try and exemplify the applications of enzyme kinetic principles. This chapter provides a brief overview outlining some key concepts within each of the sections and the chapters within this textbook.

  20. Enzyme kinetics in drug metabolism: fundamentals and applications.

    PubMed

    Nagar, Swati; Argikar, Upendra A; Tweedie, Donald J

    2014-01-01

    Enzymes are protein catalysts that lower the energy barrier for a reaction and speed the rate of a chemical change. The kinetics of reactions catalyzed by enzymes, as well as several mechanisms underlying the kinetics, have been comprehensively studied and written in textbooks (1, 2). The importance of quantitative evaluation of enzymatic processes has been recognized in many fields of study, including biochemistry, molecular biology, and pharmaceutical sciences to name a few. In pharmaceutical sciences, the applications of enzyme kinetics range from hit finding efforts for new chemical entities on a pharmacological target to concentration effect relationships to large-scale biosynthesis. The study of the science of drug metabolism has two principal concepts-rate and extent. While understanding disposition pathways and identification of metabolites provides an insight into the extent of metabolism, kinetics of depletion of substrates (endogenous or exogenous) and formation of metabolites deals with the rate of metabolism. The current textbook specifically focuses on kinetics of drug-metabolizing enzymes, detailing specific enzyme classes, and discusses kinetics as they apply to drug transporters. This textbook also outlines additional factors that contribute to the kinetics of reactions catalyzed by these proteins such as variability in isoforms (pharmacogenomics) and experimental factors including key concepts such as alterations of substrate concentrations due to binding. Applications of these approaches in predicting kinetic parameters and alternative approaches for enzymes (systems biology) and transporters are also discussed. The final section focuses on real-life examples (case studies) to try and exemplify the applications of enzyme kinetic principles. This chapter provides a brief overview outlining some key concepts within each of the sections and the chapters within this textbook. PMID:24523105

  1. Prediction of Metabolism of Drugs using Artificial Intelligence: How far have we reached?

    PubMed

    Kumar, Rajnish; Sharma, Anju; Siddiqui, Mohammed Haris; Tiwari, Rajesh Kumar

    2016-01-01

    Information about drug metabolism is an essential component of drug development. Modeling the drug metabolism requires identification of the involved enzymes, rate and extent of metabolism, the sites of metabolism etc. There has been continuous attempts in the prediction of metabolism of drugs using artificial intelligence in effort to reduce the attrition rate of drug candidates entering to preclinical and clinical trials. Currently, there are number of predictive models available for metabolism using Support vector machines, Artificial neural networks, Bayesian classifiers etc. There is an urgent need to review their progress so far and address the existing challenges in prediction of metabolism. In this attempt, we are presenting the currently available literature models and some of the critical issues regarding prediction of drug metabolism.

  2. Insights into drug metabolism from modelling studies of cytochrome P450-drug interactions.

    PubMed

    Maréchal, Jean-Didier; Sutcliffe, Michael J

    2006-01-01

    The cytochromes P450 (CYPs) comprise a vast superfamily of enzymes found in virtually all life forms. In mammals, xenobiotic metabolising CYPs provide crucial protection from the harmful effects of exposure to a wide variety of chemicals, including environmental toxins and therapeutic drugs. Elucidating the structural features of CYPs that contribute to their metabolism of structurally diverse substrates impacts on the rational design of improved therapeutic drugs and specific inhibitors. Models capable of predicting the possible involvement of CYPs in the metabolism of drugs or drug candidates are thus important tools in drug discovery and development. Ideally, functional information would be obtained from crystal structures of all the CYPs of interest. Initially only crystal structures of distantly related bacterial CYPs were available - comparative modelling techniques were used to bridge the gap and produce structural models of human CYPs, and thereby obtain some useful functional information. A significant step forward in the reliability of these models came six years ago with the first crystal structure of a mammalian CYP, rabbit CYP2C5, followed by the structures of five human enzymes, CYP2A6, CYP2C8, CYP2C9, CYP2D6 and CYP3A4, and a second rabbit enzyme, CYP2B4. The evolution of a CYP2D6 model, leading to the validation of the model as an in silico tool for predicting binding and metabolism, is presented as a case study. PMID:16918473

  3. Black leaf streak disease affects starch metabolism in banana fruit.

    PubMed

    Saraiva, Lorenzo de Amorim; Castelan, Florence Polegato; Shitakubo, Renata; Hassimotto, Neuza Mariko Aymoto; Purgatto, Eduardo; Chillet, Marc; Cordenunsi, Beatriz Rosana

    2013-06-12

    Black leaf streak disease (BLSD), also known as black sigatoka, represents the main foliar disease in Brazilian banana plantations. In addition to photosynthetic leaf area losses and yield losses, this disease causes an alteration in the pre- and postharvest behavior of the fruit. The aim of this work was to investigate the starch metabolism of fruits during fruit ripening from plants infected with BLSD by evaluating carbohydrate content (i.e., starch, soluble sugars, oligosaccharides, amylose), phenolic compound content, phytohormones, enzymatic activities (i.e., starch phosphorylases, α- and β-amylase), and starch granules. The results indicated that the starch metabolism in banana fruit ripening is affected by BLSD infection. Fruit from infested plots contained unusual amounts of soluble sugars in the green stage and smaller starch granules and showed a different pattern of superficial degradation. Enzymatic activities linked to starch degradation were also altered by the disease. Moreover, the levels of indole-acetic acid and phenolic compounds indicated an advanced fruit physiological age for fruits from infested plots. PMID:23692371

  4. Computing with evidence part II: an evidential approach to predicting metabolic drug-drug interactions

    PubMed Central

    Boyce, Richard; Collins, Carol; Horn, John; Kalet, Ira

    2009-01-01

    We describe a novel experiment that we conducted with the Drug Interaction Knowledge-base (DIKB) to determine which combinations of evidence enable a rule-based theory of metabolic drug-drug interactions to make the most optimal set of predictions. The focus of the experiment was a group of 16 drugs including six members of the HMG-CoA-reductase inhibitor family (statins). The experiment helped identify evidence-use strategies that enabled the DIKB to predict significantly more interactions present in a validation set than the most rigorous strategy developed by drug experts with no loss of accuracy. The best-performing strategies included evidence types that would normally be of lesser predictive value but that are often more accessible than more rigorous types. Our experimental methods represent a new approach to leveraging the available scientific evidence within a domain where important evidence is often missing or of questionable value for supporting important assertions. PMID:19539050

  5. The changing environment of graduate and postdoctoral training in drug metabolism: viewpoints from academia, industry, and government.

    PubMed

    Stevens, Jeffrey C; Dean, Dennis C; Preusch, Peter C; Correia, Maria Almira

    2003-04-01

    This article is an invited report of a symposium sponsored by the Drug Metabolism Division of the American Society for Pharmacology and Experimental Therapeutics held at Experimental Biology 2002 in New Orleans. The impetus for the symposium was a perceived shortage in the supply of graduate students qualified for drug metabolism research positions in industry, academia, and government. For industry, recent hiring stems largely from the expansion of drug metabolism departments in an effort to keep pace with the demands of drug discovery and new technologies. In turn, regulatory scientists are needed to review and verify the results of the increased number and volume of studies required for drug development and approval. Thus the initial source of training, academia, has been forced to recognize these external hiring pressures while trying to attract and retain the faculty, postdoctoral scientists, and students necessary for active teaching and research programs. The trend of the expansion of the interdisciplinary nature of traditional drug metabolism to include emerging technologies such as pharmacogenetics, transporters, and proteomics and the implications for future needs in training and funding were acknowledged. There was also consensus on the value of partnerships between academia and industry for increasing student interest and providing training in disciplines directly applicable to industrial drug metabolism research. Factors affecting the sources of these trainees, such as federal funding, the number of trainees per institution, and recent issues with immigration restrictions that have limited the flow of scientists were also discussed.

  6. Modifying metabolically sensitive histone marks by inhibiting glutamine metabolism affects gene expression and alters cancer cell phenotype.

    PubMed

    Simpson, Natalie E; Tryndyak, Volodymyr P; Pogribna, Marta; Beland, Frederick A; Pogribny, Igor P

    2012-12-01

    The interplay of metabolism and epigenetic regulatory mechanisms has become a focal point for a better understanding of cancer development and progression. In this study, we have acquired data supporting previous observations that demonstrate glutamine metabolism affects histone modifications in human breast cancer cell lines. Treatment of non-invasive epithelial (T-47D and MDA-MB-361) and invasive mesenchymal (MDA-MB-231 and Hs-578T) breast cancer cell lines with the glutaminase inhibitor, Compound 968, resulted in cytotoxicity in all cell lines, with the greatest effect being observed in MDA-MB-231 breast cancer cells. Compound 968-treatment induced significant downregulation of 20 critical cancer-related genes, the majority of which are anti-apoptotic and/or promote metastasis, including AKT, BCL2, BCL2L1, CCND1, CDKN3, ERBB2, ETS1, E2F1, JUN, KITLG, MYB, and MYC. Histone H3K4me3, a mark of transcriptional activation, was reduced at the promoters of all but one of these critical cancer genes. The decrease in histone H3K4me3 at global and gene-specific levels correlated with reduced expression of SETD1 and ASH2L, genes encoding the histone H3K4 methyltransferase complex. Further, the expression of other epigenetic regulatory genes, known to be downregulated during apoptosis (e.g., DNMT1, DNMT3B, SETD1 and SIRT1), was also downregulated by Compound 968. These changes in gene expression and histone modifications were accompanied by the activation of apoptosis, and decreased invasiveness and resistance of MDA-MB-231 cells to chemotherapeutic drug doxorubicin. The results of this study provide evidence to a link between cytotoxicity caused by inhibiting glutamine metabolism with alterations of the epigenome of breast cancer cells and suggest that modification of intracellular metabolism may enhance the efficiency of epigenetic therapy. PMID:23117580

  7. Metabolism of anabolic steroids and their relevance to drug detection in horseracing.

    PubMed

    Teale, Philip; Houghton, Edward

    2010-06-01

    The fight against doping in sport using analytical chemistry is a mature area with a history of approximately 100 years in horseracing. In common with human sport, anabolic/androgenic steroids (AASs) are an important group of potential doping agents. Particular issues with their detection are extensive metabolism including both phase I and phase II. A number of the common AASs are also endogenous to the equine. A further issue is the large number of synthetic steroids produced as pharmaceutical products or as 'designer' drugs intended to avoid detection or for the human supplement market. An understanding of the metabolism of AASs is vital to the development of effective detection methods for equine sport. The aim of this paper is to review current knowledge of the metabolism of appropriate steroids, the current approaches to their detection in equine sport and future trends that may affect equine dope testing.

  8. Methodologies for investigating drug metabolism at the early drug discovery stage: prediction of hepatic drug clearance and P450 contribution.

    PubMed

    Emoto, Chie; Murayama, Norie; Rostami-Hodjegan, Amin; Yamazaki, Hiroshi

    2010-10-01

    The attrition rate in drug development is being reduced by continuous advances in science and technology introduced by various academic institutions and pharmaceutical companies. This has been certainly noticeable in reducing the frequency with which unfavorable absorption, distribution, metabolism, and elimination (ADME) characteristics of any candidate drug causes failure in clinical development. Nonetheless, it is important that the objectives in reducing attrition during later stages of development are matched by information generated in the earliest stage of discovery. In this review, we summarize the methodologies employed during the early stages of drug discovery and discuss new findings in the areas of (1) drug metabolism enzymes, (2) the contribution of cytochrome P450 enzymes (P450, CYP) to hepatic metabolism, (3) prediction of hepatic intrinsic clearance, (4) reaction phenotyping, and (5) the metabolic differences between highly homologous enzymes such as CYP3A4 and CYP3A5. The total contribution of P450 and UDP-glucuronosyltransferases to drug metabolism is reported to be more than 80%; therefore, glucuronidation is increasingly recognized as an important clearance pathway in addition to that of P450 enzymes. When estimating the contribution of P450, interpreting the results of inhibition studies using a single P450 inhibitor can lead to false conclusions. For instance, 1-aminobenzotriazole and SKF-525A have a varying range of IC(50) values for inhibition of drug exidation-reaction by different CYP450 enzymes. There are disparities between methodologies at early stage drug discovery and late stage development. For example, although the drug depletion approach for the prediction of hepatic intrinsic clearance may not be desirable at late stages of development, it is suitable at the early drug discovery stage since kinetic characterization and measurement of specific drug metabolites are not required. Data from protein binding assays in plasma and

  9. Factors affecting drug-induced liver injury: antithyroid drugs as instances.

    PubMed

    Heidari, Reza; Niknahad, Hossein; Jamshidzadeh, Akram; Abdoli, Narges

    2014-09-01

    Methimazole and propylthiouracil have been used in the management of hyperthyroidism for more than half a century. However, hepatotoxicity is one of the most deleterious side effects associated with these medications. The mechanism(s) of hepatic injury induced by antithyroid agents is not fully recognized yet. Furthermore, there are no specific tools for predicting the occurrence of hepatotoxicity induced by these drugs. The purpose of this article is to give an overview on possible susceptibility factors in liver injury induced by antithyroid agents. Age, gender, metabolism characteristics, alcohol consumption, underlying diseases, immunologic mechanisms, and drug interactions are involved in enhancing antithyroid drugs-induced hepatic damage. An outline on the clinically used treatments for antithyroid drugs-induced hepatotoxicity and the potential therapeutic strategies found to be effective against this complication are also discussed.

  10. Factors affecting drug-induced liver injury: antithyroid drugs as instances

    PubMed Central

    Niknahad, Hossein; Jamshidzadeh, Akram; Abdoli, Narges

    2014-01-01

    Methimazole and propylthiouracil have been used in the management of hyperthyroidism for more than half a century. However, hepatotoxicity is one of the most deleterious side effects associated with these medications. The mechanism(s) of hepatic injury induced by antithyroid agents is not fully recognized yet. Furthermore, there are no specific tools for predicting the occurrence of hepatotoxicity induced by these drugs. The purpose of this article is to give an overview on possible susceptibility factors in liver injury induced by antithyroid agents. Age, gender, metabolism characteristics, alcohol consumption, underlying diseases, immunologic mechanisms, and drug interactions are involved in enhancing antithyroid drugs-induced hepatic damage. An outline on the clinically used treatments for antithyroid drugs-induced hepatotoxicity and the potential therapeutic strategies found to be effective against this complication are also discussed. PMID:25320726

  11. Profiles in drug metabolism and toxicology: Richard Tecwyn Williams (1909-1979).

    PubMed

    Jones, Alan Wayne

    2015-01-01

    This article pays homage to the life and work of a veritable pioneer in toxicology and drug metabolism, namely a Welshman, Richard Tecwyn Williams, FRS. Professor Williams, or RT as he was known, made major contributions to knowledge about the metabolism and toxicology of drugs and xenobiotics during a scientific career spanning nearly 50 years. Author or coauthor of close to 400 research articles and reviews, including a classic book, entitled Detoxication Mechanisms, Williams and his research school investigated virtually all aspects of drug metabolism, especially conjugations. In particular, the concepts of phase 1 and phase II metabolic pathways were introduced by Williams; the biliary excretion of drugs was extensively studied as were species differences in drug metabolism and detoxication. Besides investigating the metabolism of many pharmaceutical drugs, such as sulfonamides and thalidomide, Williams and his group investigated the disposition and fate in the body of organic pesticides and recreational drugs of abuse, such as amphetamine, methamphetamine and lysergic acid diethylamide (LSD).

  12. Inter-donor variability of phase I/phase II metabolism of three reference drugs in cryopreserved primary human hepatocytes in suspension and monolayer.

    PubMed

    den Braver-Sewradj, Shalenie P; den Braver, Michiel W; Vermeulen, Nico P E; Commandeur, Jan N M; Richert, Lysiane; Vos, J Chris

    2016-06-01

    Cytochrome P450s (CYPs), UDP-glucuronosyltransferases (UGTs) and sulfotransferases (SULTs) are the most important enzymes for metabolic clearance. Characterization of phase I and phase II metabolism of a given drug in cellular models is therefore important for an adequate interpretation of the role of drug metabolism in toxicity. We investigated phase I (CYP) and phase II (UGT and SULT) metabolism of three drugs related to drug-induced liver injury (DILI), namely acetaminophen (APAP), diclofenac (DF) and tolcapone (TC), in cryopreserved primary human hepatocytes from 5 donors in suspension and monolayer. The general phase II substrate 7-hydroxycoumarin (7-HC) was included for comparison. Our results show that the decrease in CYP, UGT and SULT activity after plating is substrate dependent. As a consequence the phase I/phase II metabolism ratio is significantly affected, with a shift in monolayer towards phase I metabolism for TC and towards phase II metabolism for APAP and DF. Inter-donor variability in drug metabolism is significant, especially in sulfation of 7-HC or APAP. As CYP, UGT and SULT metabolism may lead to bioactivation and/or detoxification of drugs, a changed ratio in phase I/phase II metabolism may have important consequences for metabolism-related toxicity. PMID:26921663

  13. Measuring Drug Metabolism Kinetics and Drug-Drug Interactions Using Self-Assembled Monolayers for Matrix-Assisted Laser Desorption-Ionization Mass Spectrometry.

    PubMed

    Anderson, Lyndsey L; Berns, Eric J; Bugga, Pradeep; George, Alfred L; Mrksich, Milan

    2016-09-01

    The competition of two drugs for the same metabolizing enzyme is a common mechanism for drug-drug interactions that can lead to altered kinetics in drug metabolism and altered elimination rates in vivo. With the prevalence of multidrug therapy, there is great potential for serious drug-drug interactions and adverse drug reactions. In an effort to prevent adverse drug reactions, the FDA mandates the evaluation of the potential for metabolic inhibition by every new chemical entity. Conventional methods for assaying drug metabolism (e.g., those based on HPLC) have been established for measuring drug-drug interactions; however, they are low-throughput. Here we describe an approach to measure the catalytic activity of CYP2C9 using the high-throughput technique self-assembled monolayers for matrix-assisted laser desorption-ionization (SAMDI) mass spectrometry. We measured the kinetics of CYP450 metabolism of the substrate, screened a set of drugs for inhibition of CYP2C9 and determined the Ki values for inhibitors. The throughput of this platform may enable drug metabolism and drug-drug interactions to be interrogated at a scale that cannot be achieved with current methods. PMID:27467208

  14. Multiple dietary supplements do not affect metabolic and cardiovascular health.

    PubMed

    Soare, Andreea; Weiss, Edward P; Holloszy, John O; Fontana, Luigi

    2013-09-01

    Dietary supplements are widely used for health purposes. However, little is known about the metabolic and cardiovascular effects of combinations of popular over-the-counter supplements, each of which has been shown to have anti-oxidant, anti-inflammatory and pro-longevity properties in cell culture or animal studies. This study was a 6-month randomized, single-blind controlled trial, in which 56 non-obese (BMI 21.0-29.9 kg/m2) men and women, aged 38 to 55 yr, were assigned to a dietary supplement (SUP) group or control (CON) group, with a 6-month follow-up. The SUP group took 10 dietary supplements each day (100 mg of resveratrol, a complex of 800 mg each of green, black, and white tea extract, 250 mg of pomegranate extract, 650 mg of quercetin, 500 mg of acetyl-l-carnitine, 600 mg of lipoic acid, 900 mg of curcumin, 1 g of sesamin, 1.7 g of cinnamon bark extract, and 1.0 g fish oil). Both the SUP and CON groups took a daily multivitamin/mineral supplement. The main outcome measures were arterial stiffness, endothelial function, biomarkers of inflammation and oxidative stress, and cardiometabolic risk factors. Twenty-four weeks of daily supplementation with 10 dietary supplements did not affect arterial stiffness or endothelial function in nonobese individuals. These compounds also did not alter body fat measured by DEXA, blood pressure, plasma lipids, glucose, insulin, IGF-1, and markers of inflammation and oxidative stress. In summary, supplementation with a combination of popular dietary supplements has no cardiovascular or metabolic effects in non-obese relatively healthy individuals.

  15. Evaluation of Factors Affecting Powdered Drug Reconstitution in Microgravity

    NASA Technical Reports Server (NTRS)

    Schaffner, Grant; Johnston, Smith; Marshburn, Tom

    1999-01-01

    standard pharmacological supplies. The experiment included a parametric assessment of possible factors affecting the reconstitution process. The specific questions that we wished to answer were: (1) Is it possible to reconstitute powdered drugs in weightlessness using standard pharmacological equipment? (2) What are the differences between drug reconstitution in a 1-G and a 0-G environment? (3) What techniques of mixing the drug powder and diluent are more successful? (4) What physical and chemical factors play a role in determining the success of mixing and dissolution? (5) Is it necessary to employ crewmember and equipment restraints during the reconstitution process?

  16. 77 FR 64346 - Endocrinologic and Metabolic Drugs Advisory Committee; Amendment of Notice

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-19

    ... Administration (FDA) is announcing an amendment to the notice of meeting of the Endocrinologic and Metabolic Drugs Advisory Committee. This meeting was announced in the Federal Register of October 10, 2012 (77 FR... HUMAN SERVICES Food and Drug Administration Endocrinologic and Metabolic Drugs Advisory...

  17. Biotransformation of anthelmintics and the activity of drug-metabolizing enzymes in the tapeworm Moniezia expansa.

    PubMed

    Prchal, Lukáš; Bártíková, Hana; Bečanová, Aneta; Jirásko, Robert; Vokřál, Ivan; Stuchlíková, Lucie; Skálová, Lenka; Kubíček, Vladimír; Lamka, Jiří; Trejtnar, František; Szotáková, Barbora

    2015-04-01

    The sheep tapeworm Moniezia expansa is very common parasite, which affects ruminants such as sheep, goats as well as other species. The benzimidazole anthelmintics albendazole (ABZ), flubendazole (FLU) and mebendazole (MBZ) are often used to treat the infection. The drug-metabolizing enzymes of helminths may alter the potency of anthelmintic treatment. The aim of our study was to assess the activity of the main drug-metabolizing enzymes and evaluate the metabolism of selected anthelmintics (ABZ, MBZ and FLU) in M. expansa. Activities of biotransformation enzymes were determined in subcellular fractions. Metabolites of the anthelmintics were detected and identified using high performance liquid chromatography/ultra-violet/VIS/fluorescence or ultra-high performance liquid chromatography/mass spectrometry. Reduction of MBZ, FLU and oxidation of ABZ were proved as well as activities of various metabolizing enzymes. Despite the fact that the conjugation enzymes glutathione S-transferase, UDP-glucuronosyl transferase and UDP-glucosyl transferase were active in vitro, no conjugated metabolites of anthelmintics were identified either ex vivo or in vitro. The obtained results indicate that sheep tapeworm is able to deactivate the administered anthelmintics, and thus protects itself against their action.

  18. Drug addiction: An affective-cognitive disorder in need of a cure.

    PubMed

    Fattore, Liana; Diana, Marco

    2016-06-01

    Drug addiction is a compulsive behavioral abnormality. In spite of pharmacological treatments and psychosocial support to reduce or eliminate drug intake, addiction tends to persist over time. Preclinical and human observations have converged on the hypothesis that addiction represents the pathological deterioration of neural processes that normally serve affective and cognitive functioning. The major elements of persistent compulsive drug use are hypothesized to be structural, cellular and molecular that underlie enduring changes in several forebrain circuits that receive input from midbrain dopamine neurons and are involved in affective (e.g. ventral striatum) and cognitive (e.g. prefrontal cortex) mechanisms. Here we review recent progress in identifying crucial elements useful to understand the pathophysiology of the disease and its treatments. Manipulation of neuropeptides brain systems and pharmacological targeting of κ-opioid receptors and/or drug metabolism may hold beneficial effects at affective and cognitive level. Non-pharmacological, highly innovative approaches such as Transcranial Magnetic Stimulation may reveal unsuspected potential and promise to be the first neurobiology-based therapeutics in addiction. PMID:27095547

  19. INFLUENCE OF DIETARY SUBSTANCES ON INTESTINAL DRUG METABOLISM AND TRANSPORT

    PubMed Central

    Won, Christina S.; Oberlies, Nicholas H.; Paine, Mary F.

    2011-01-01

    Successful delivery of promising new chemical entities via the oral route is rife with challenges, some of which cannot be explained or foreseen during drug development. Further complicating an already multifaceted problem is the obvious, yet often overlooked, effect of dietary substances on drug disposition and response. Some dietary substances, particularly fruit juices, have been shown to inhibit biochemical processes in the intestine, leading to altered pharmacokinetic (PK), and potentially pharmacodynamic (PD), outcomes. Inhibition of intestinal CYP3A-mediated metabolism is the major mechanism by which fruit juices, including grapefruit juice, enhances systemic exposure to new and already marketed drugs. Inhibition of intestinal non-CYP3A enzymes and apically-located transport proteins represent recently identified mechanisms that can alter PK and PD. Several fruit juices have been shown to inhibit these processes in vitro, but some interactions have not translated to the clinic. The lack of in vitro-in vivo concordance is due largely to a lack of rigorous methods to elucidate causative ingredients prior to clinical testing. Identification of specific components and underlying mechanisms is challenging, as dietary substances frequently contain multiple, often unknown, bioactive ingredients that vary in composition and bioactivity. A translational research approach, combining expertise from clinical pharmacologists and natural products chemists, is needed to develop robust models describing PK/PD relationships between a given dietary substance and drug of interest. Validation of these models through well-designed clinical trials would facilitate development of common practice guidelines for managing drug-dietary substance interactions appropriately. PMID:21189136

  20. Discovery of Anthelmintic Drug Targets and Drugs Using Chokepoints in Nematode Metabolic Pathways

    PubMed Central

    Taylor, Christina M.; Wang, Qi; Rosa, Bruce A.; Huang, Stanley Ching-Cheng; Powell, Kerrie; Schedl, Tim; Pearce, Edward J.; Abubucker, Sahar; Mitreva, Makedonka

    2013-01-01

    Parasitic roundworm infections plague more than 2 billion people (1/3 of humanity) and cause drastic losses in crops and livestock. New anthelmintic drugs are urgently needed as new drug resistance and environmental concerns arise. A “chokepoint reaction” is defined as a reaction that either consumes a unique substrate or produces a unique product. A chokepoint analysis provides a systematic method of identifying novel potential drug targets. Chokepoint enzymes were identified in the genomes of 10 nematode species, and the intersection and union of all chokepoint enzymes were found. By studying and experimentally testing available compounds known to target proteins orthologous to nematode chokepoint proteins in public databases, this study uncovers features of chokepoints that make them successful drug targets. Chemogenomic screening was performed on drug-like compounds from public drug databases to find existing compounds that target homologs of nematode chokepoints. The compounds were prioritized based on chemical properties frequently found in successful drugs and were experimentally tested using Caenorhabditis elegans. Several drugs that are already known anthelmintic drugs and novel candidate targets were identified. Seven of the compounds were tested in Caenorhabditis elegans and three yielded a detrimental phenotype. One of these three drug-like compounds, Perhexiline, also yielded a deleterious effect in Haemonchus contortus and Onchocerca lienalis, two nematodes with divergent forms of parasitism. Perhexiline, known to affect the fatty acid oxidation pathway in mammals, caused a reduction in oxygen consumption rates in C. elegans and genome-wide gene expression profiles provided an additional confirmation of its mode of action. Computational modeling of Perhexiline and its target provided structural insights regarding its binding mode and specificity. Our lists of prioritized drug targets and drug-like compounds have potential to expedite the discovery

  1. Targeting Plasmodium Metabolism to Improve Antimalarial Drug Design.

    PubMed

    Avitia-Domínguez, Claudia; Sierra-Campos, Erick; Betancourt-Conde, Irene; Aguirre-Raudry, Miriam; Vázquez-Raygoza, Alejandra; Luevano-De la Cruz, Artemisa; Favela-Candia, Alejandro; Sarabia-Sanchez, Marie; Ríos-Soto, Lluvia; Méndez-Hernández, Edna; Cisneros-Martínez, Jorge; Palacio-Gastélum, Marcelo Gómez; Valdez-Solana, Mónica; Hernández-Rivera, Jessica; De Lira-Sánchez, Jaime; Campos-Almazán, Mara; Téllez-Valencia, Alfredo

    2016-01-01

    Malaria is one of the main infectious diseases in tropical developing countries and represents high morbidity and mortality rates nowadays. The principal etiological agent P. falciparum is transmitted through the bite of the female Anopheles mosquito. The issue has escalated due to the emergence of resistant strains to most of the antimalarials used for the treatment including Chloroquine, Sulfadoxine-Pyrimethamine, and recently Artemisinin derivatives, which has led to diminished effectiveness and by consequence increased the severity of epidemic outbreaks. Due to the lack of effective compounds to treat these drug-resistant strains, the discovery or development of novel anti-malaria drugs is important. In this context, one strategy has been to find inhibitors of enzymes, which play an important role for parasite survival. Today, promising results have been obtained in this regard, involving the entire P. falciparum metabolism. These inhibitors could serve as leads in the search of a new chemotherapy against malaria. This review focuses on the achievements in recent years with regard to inhibition of enzymes used as targets for drug design against malaria. PMID:26983887

  2. An evaluation of tandem mass spectrometry in drug metabolism studies.

    PubMed

    Naylor, S; Kajbaf, M; Lamb, J H; Jahanshahi, M; Gorrod, J W

    1993-07-01

    The use of precursor ion and constant neutral loss scanning as a means of rapidly detecting drug metabolites is evaluated. Four clinically useful drugs, namely (i) cyclophosphamide, (ii) mifentidine, (iii) cimetropium bromide and (iv) haloperidol, were subjected to microsomal incubations to afford phase I metabolites. Aside from a minor clean-up procedure involving zinc sulfate precipitation of microsomal proteins and solid-phase extraction of metabolites using a Sep-pak C-18 cartridge, the mixtures were analysed directly by fast atom bombardment tandem mass spectrometry. It is demonstrated that such screening strategies are important in detecting novel metabolites. However, there are some problems associated with only using such methods, including (i) the possibility of not detecting metabolites that undergo unusual collision-induced dissociation fragmentation pathways, (ii) the non-detection of metabolites that have undergone metabolic change at unusual sites of reactivity, and (iii) production of artifacts derived from the parent drug by the primary ionization process. Examples are discussed that highlight both the strengths and weaknesses of such an approach.

  3. Factors affecting the development of adverse drug reactions (Review article)

    PubMed Central

    Alomar, Muaed Jamal

    2013-01-01

    Objectives To discuss the effect of certain factors on the occurrence of Adverse Drug Reactions (ADRs). Data Sources A systematic review of the literature in the period between 1991 and 2012 was made based on PubMed, the Cochrane database of systematic reviews, EMBASE and IDIS. Key words used were: medication error, adverse drug reaction, iatrogenic disease factors, ambulatory care, primary health care, side effects and treatment hazards. Summary Many factors play a crucial role in the occurrence of ADRs, some of these are patient related, drug related or socially related factors. Age for instance has a very critical impact on the occurrence of ADRs, both very young and very old patients are more vulnerable to these reactions than other age groups. Alcohol intake also has a crucial impact on ADRs. Other factors are gender, race, pregnancy, breast feeding, kidney problems, liver function, drug dose and frequency and many other factors. The effect of these factors on ADRs is well documented in the medical literature. Taking these factors into consideration during medical evaluation enables medical practitioners to choose the best drug regimen. Conclusion Many factors affect the occurrence of ADRs. Some of these factors can be changed like smoking or alcohol intake others cannot be changed like age, presence of other diseases or genetic factors. Understanding the different effects of these factors on ADRs enables healthcare professionals to choose the most appropriate medication for that particular patient. It also helps the healthcare professionals to give the best advice to patients. Pharmacogenomics is the most recent science which emphasizes the genetic predisposition of ADRs. This innovative science provides a new perspective in dealing with the decision making process of drug selection. PMID:24648818

  4. Leptin expression affects metabolic rate in zebrafish embryos (D. rerio).

    PubMed

    Dalman, Mark R; Liu, Qin; King, Mason D; Bagatto, Brian; Londraville, Richard L

    2013-01-01

    We used antisense morpholino oligonucleotide technology to knockdown leptin-(A) gene expression in developing zebrafish embryos and measured its effects on metabolic rate and cardiovascular function. Using two indicators of metabolic rate, oxygen consumption was significantly lower in leptin morphants early in development [<48 hours post-fertilization (hpf)], while acid production was significantly lower in morphants later in development (>48 hpf). Oxygen utilization rates in <48 hpf embryos and acid production in 72 hpf embryos could be rescued to that of wildtype embryos by recombinant leptin coinjected with antisense morpholino. Leptin is established to influence metabolic rate in mammals, and these data suggest leptin signaling also influences metabolic rate in fishes.

  5. [A review of drug metabolism under hypoxia environment at high altitude].

    PubMed

    Zhang, Juan-ling; Li, Xiang-yang

    2015-09-01

    The special environmental features of high altitude, such as hypobaric hypoxia, low temperature, arid, high solar radiation, variable climate and geochemical anomaly, cause great effects on human physiology and health. It will provide valuable references and new ideas to study drug's metabolism in special environment of high altitude hypoxia, and give the guidance to clinical reasonable medication, avoiding adverse reactions and personalized medicine in plateau areas. This article reviewed the effect of high altitude hypoxia on drug metabolism, elaborated metabolic characteristics of some drugs and the activity and expression of drug metabolism enzymes under hypoxia environment at high altitude, and discussed related mechanism.

  6. [A review of drug metabolism under hypoxia environment at high altitude].

    PubMed

    Zhang, Juan-ling; Li, Xiang-yang

    2015-09-01

    The special environmental features of high altitude, such as hypobaric hypoxia, low temperature, arid, high solar radiation, variable climate and geochemical anomaly, cause great effects on human physiology and health. It will provide valuable references and new ideas to study drug's metabolism in special environment of high altitude hypoxia, and give the guidance to clinical reasonable medication, avoiding adverse reactions and personalized medicine in plateau areas. This article reviewed the effect of high altitude hypoxia on drug metabolism, elaborated metabolic characteristics of some drugs and the activity and expression of drug metabolism enzymes under hypoxia environment at high altitude, and discussed related mechanism. PMID:26757541

  7. Campomanesia adamantium extract induces DNA damage, apoptosis, and affects cyclophosphamide metabolism.

    PubMed

    Martello, M D; David, N; Matuo, R; Carvalho, P C; Navarro, S D; Monreal, A C D; Cunha-Laura, A L; Cardoso, C A L; Kassuya, C A L; Oliveira, R J

    2016-01-01

    Campomanesia adamantium (Cambess.) O. Berg. is originally from Brazil. Its leaves and fruits have medicinal properties such as anti-inflammatory, antidiarrheal and antiseptic properties. However, the mutagenic potential of this species has been reported in few studies. This study describes the mutagenic/antimutagenic, splenic phagocytic, and apoptotic activities of C. adamantium hydroethanolic extract with or without cyclophosphamide in Swiss mice. The animals orally received the hydroethanolic extract at doses of 30, 100, or 300 mg/kg with or without 100 mg/kg cyclophosphamide. Mutagenesis was evaluated by performing the micronucleus assay after treatment for 24, 48, and 72 h, while splenic phagocytic and apoptotic effects were investigated after 72 h. Short-term exposure of 30 and 100 mg/kg extract induced mild clastogenic/aneugenic effects and increased splenic phagocytosis and apoptosis in the liver, spleen, and kidneys. When the extract was administered in combination with cyclophosphamide, micronucleus frequency and apoptosis reduced. Extract components might affect cyclophosphamide metabolism, which possibly leads to increased clearance of this chemotherapeutic agent. C. adamantium showed mutagenic activity and it may decrease the effectiveness of drugs with metabolic pathways similar to those associated with cyclophosphamide. Thus, caution should be exercised while consuming these extracts, especially when received in combination with other drugs. PMID:27173259

  8. Campomanesia adamantium extract induces DNA damage, apoptosis, and affects cyclophosphamide metabolism.

    PubMed

    Martello, M D; David, N; Matuo, R; Carvalho, P C; Navarro, S D; Monreal, A C D; Cunha-Laura, A L; Cardoso, C A L; Kassuya, C A L; Oliveira, R J

    2016-04-26

    Campomanesia adamantium (Cambess.) O. Berg. is originally from Brazil. Its leaves and fruits have medicinal properties such as anti-inflammatory, antidiarrheal and antiseptic properties. However, the mutagenic potential of this species has been reported in few studies. This study describes the mutagenic/antimutagenic, splenic phagocytic, and apoptotic activities of C. adamantium hydroethanolic extract with or without cyclophosphamide in Swiss mice. The animals orally received the hydroethanolic extract at doses of 30, 100, or 300 mg/kg with or without 100 mg/kg cyclophosphamide. Mutagenesis was evaluated by performing the micronucleus assay after treatment for 24, 48, and 72 h, while splenic phagocytic and apoptotic effects were investigated after 72 h. Short-term exposure of 30 and 100 mg/kg extract induced mild clastogenic/aneugenic effects and increased splenic phagocytosis and apoptosis in the liver, spleen, and kidneys. When the extract was administered in combination with cyclophosphamide, micronucleus frequency and apoptosis reduced. Extract components might affect cyclophosphamide metabolism, which possibly leads to increased clearance of this chemotherapeutic agent. C. adamantium showed mutagenic activity and it may decrease the effectiveness of drugs with metabolic pathways similar to those associated with cyclophosphamide. Thus, caution should be exercised while consuming these extracts, especially when received in combination with other drugs.

  9. The use of drug metabolism for prediction of intestinal permeability (dagger).

    PubMed

    Chen, Mei-Ling; Yu, Lawrence

    2009-01-01

    The Biopharmaceutics Classification System (BCS), based on the aqueous solubility and intestinal permeability of a drug substance, has been widely used to predict the extent of drug absorption during the course of pharmaceutical development. Combined with product dissolution data, this system has gained a prominent role in regulatory process to determine if a drug formulated in an immediate release solid oral dosage form qualifies for waiver of in vivo bioequivalence studies. In parallel, the Biopharmaceutics Drug Disposition Classification System (BDDCS), using aqueous solubility and drug metabolism, takes on another venue to predict overall drug disposition. It has been suggested that the matrix of drug metabolism in BDDCS can be used to substantiate the classification of permeability by BCS. A total of 51 drugs were compiled in this study to examine the use of drug metabolism for predicting permeability. All compounds were classified as high permeability based on BCS, but only 73% of the compounds were found to exhibit extensive metabolism. Lipophilicity accounts for significant metabolism of many highly permeable drugs. Fourteen (14) out of 51 drugs have poor metabolism, suggesting that high permeability as defined by BCS does not necessarily dictate extensive metabolism. The drugs that have high permeability but poor metabolism are generally hydrophilic molecules with low molecular weight and are likely to be absorbed by active transport mechanisms. Based on the present data and literature information, it seems logical to predict that the extent of absorption is mostly complete (or > or =90%) if the drug is subject to a high degree of metabolism (e.g., > or =90%). The extent of drug metabolism may be useful in supporting permeability classification under certain circumstances.

  10. Serum cyclosporin levels, hepatic drug metabolism and renal tubulotoxicity.

    PubMed

    Cunningham, C; Gavin, M P; Whiting, P H; Burke, M D; Macintyre, F; Thomson, A W; Simpson, J G

    1984-09-15

    The present study was designed to examine inter-relationships between serum cyclosporin (CsA) levels, hepatic drug metabolising enzyme activity and CsA induced nephrotoxicity. CsA (25 mg/kg p.o.) was administered daily to male Sprague-Dawley rats: groups of animals were killed on days 0, 4, 7, 10 and 14 and thereafter at weekly intervals over the 7-week course of the experiment. Nephrotoxicity was evaluated by measuring tubular enzymuria and by light microscopy and serum CsA levels (parent drug plus certain metabolites) were determined by radioimmunoassay. The hepatic microsomal mono-oxygenase enzyme system was monitored by measurement of cytochrome P-450, aminopyrine N-demethylase and NADPH-cytochrome c reductase. Nephrotoxicity appeared within 4 days of starting treatment and continued for 4 weeks. Between weeks 4 and 6 there was a period of complete remission followed by the return of renal damage. Aminopyrine N-demethylase activity fell during the first 4 weeks. During the period of remission, however, N-demethylase activity rose to a point significantly higher than pretreatment values and serum CsA levels fell to their lowest concentration. With relapse, hepatic N-demethylase activity again fell below normal and serum drug levels rose to their pre-remission values. From the third week onward, changes in NADPH-cytochrome c reductase activity paralleled those in N-demethylase activity. The hepatic microsomal concentration of cytochrome P-450 did not, however, change significantly during the 7-week period of CsA treatment. Our results suggest that the spontaneous remission of CsA-induced nephrotoxicity is due to a reduction in circulating drug levels caused by increased hepatic CsA metabolism.

  11. Sirtuins: Novel targets for metabolic disease in drug development

    SciTech Connect

    Jiang Weijian

    2008-08-29

    Calorie restriction extends lifespan and produces a metabolic profile desirable for treating diseases such as type 2 diabetes. SIRT1, an NAD{sup +}-dependent deacetylase, is a principal modulator of pathways downstream of calorie restriction that produces beneficial effects on glucose homeostasis and insulin sensitivity. Activation of SIRT1 leads to enhanced activity of multiple proteins, including peroxisome proliferator-activated receptor coactivator-1{alpha} (PGC-1{alpha}) and FOXO which helps to mediate some of the in vitro and in vivo effects of sirtuins. Resveratrol, a polyphenolic SIRT1 activator, mimics the effects of calorie restriction in lower organisms and in mice fed a high-fat diet ameliorates insulin resistance. In this review, we summarize recent research advances in unveiling the molecular mechanisms that underpin sirtuin as therapeutic candidates and discuss the possibility of using resveratrol as potential drug for treatment of diabetes.

  12. Comparative drug metabolism and disposition in minor species.

    PubMed

    Short, C R; Barker, S A; Flory, W

    1988-01-01

    The disposition of fenbendazole (FBZ) was studied in vivo in cattle (steers), goats, chickens, ducks, turkeys and rabbits, and in vitro in hepatic enzyme preparations from cattle, sheep, goats, rabbits, rats, chickens, ducks, turkeys and catfish. The major excretory metabolite when FBZ was administered either iv or po (5 mg/kg) was p-hydroxyfenbendazole (FBZ-OH). The sulfoxide (FBZ-SO) and sulfone (FBZ-SO2) appeared in plasma but were recovered in only trace amounts in urine or feces, and the amine (FBZ-NH2) was a minor metabolite appearing only occasionally in plasma. The greatest species differences were seen among the avian species, and differences in metabolite excretion correlated well with the ability of the species to metabolize the drug (especially to FBZ-OH) in vitro. Other in vitro studies measured the rate of oxidative, hydrolytic, and conjugative (glucuronide, acetate, sulfate) pathways in liver preparations.

  13. Targeting drug-metabolizing enzymes for effective chemoprevention and chemotherapy.

    PubMed

    Swanson, Hollie I; Njar, Vincent C O; Yu, Zhen; Castro, David J; Gonzalez, Frank J; Williams, David E; Huang, Ying; Kong, Ah-Ng T; Doloff, Joshua C; Ma, Jie; Waxman, David J; Scott, Emily E

    2010-04-01

    The primary focus of chemoprevention research is the prevention of cancer using pharmacological, biological, and nutritional interventions. Chemotherapeutic approaches that have been used successfully for both the prevention and treatment of a number of human malignancies have arisen from the identification of specific agents and appropriate molecular targets. Although drug-metabolizing enzymes have historically been targeted in attempts to block the initial, genotoxic events associated with the carcinogenic process, emerging evidence supports the idea that manipulating drug-metabolizing enzymes may also be an effective strategy to be used for treating tumor progression, invasion, and, perhaps, metastasis. This report summarizes a symposium that presents some recent progress in this area. One area of emphasis is the development of a CYP17 inhibitor for treatment of prostate cancer that may also have androgen-independent anticancer activity at higher concentrations. A second focus is the use of a mouse model to investigate the effects of aryl hydrocarbon receptor and Cyp1b1 status and chemopreventative agents on transplacental cancer. A third area of focus is the phytochemical manipulation of not only cytochrome P450 (P450) enzymes but also phase II inflammatory and antioxidant enzymes via the nuclear factor-erythroid 2-related factor 2 pathway to block tumor progression. A final highlight is the use of prodrugs activated by P450 enzymes to halt tumor growth and considerations of dosing schedule and targeted delivery of the P450 transgene to tumor tissue. In addition to highlighting recent successes in these areas, limitations and areas that should be targeted for further investigation are discussed. PMID:20233842

  14. Drug metabolizing enzyme systems in the houbara bustard (Chlamydotis undulata).

    PubMed

    Bailey, T A; John, A; Mensah-Brown, E P; Garner, A; Samour, J; Raza, H

    1998-10-01

    This study compared catalytic and immunochemical properties of drug metabolizing phase I and II enzyme systems in houbara bustard (Chlamydotis undulata) liver and kidney and rat liver. P450 content in bustard liver (0.34 +/- 0.03 nmol mg-1 protein) was 50% lower than that of rat liver (0.70 +/- 0.02 nmol mg-1 protein). With the exception of aniline hydroxylase activity, monooxygenase activities using aminopyrine, ethoxyresorufin and ethoxycoumarin as substrates were all significantly lower than corresponding rat liver enzymes. As found in mammalian systems the P450 activities in the bird liver were higher than in the kidney. Immunohistochemical analysis of microsomes using antibodies to rat hepatic P450 demonstrated that bustard liver and kidney express P4502C11 homologous protein; no appreciable cross-reactivity was observed in bustards using antibodies to P4502E1, 1A1 or 1A2 isoenzymes. Glutathione content and glutathione S-transferase (GST) activity in bustard liver were comparable with those of rat liver. GST activity in the kidney was 65% lower than the liver. Western blotting of liver and kidney cytosol with human GST isoenzyme-specific antibodies revealed that the expression of alpha-class of antibodies exceeds mu in the bustard. In contrast, the pi-class of GST was not detected in the bustard liver. This data demonstrates that hepatic and renal microsomes from the bustard have multiple forms of phase I and phase II enzymes. The multiplicity and tissue specific expression of xenobiotic metabolizing enzymes in bustards may play a significant role in determining the pharmacokinetics of drugs and susceptibility of the birds to various environmental pollutants and toxic insults.

  15. Effects of Radiation and Dietary Iron on Expression of Genes and Proteins Involved in Drug Metabolism

    NASA Technical Reports Server (NTRS)

    Faust, K. M.; Wotring, V. E.

    2014-01-01

    .5. RESULTS Among the redox homeostasis genes examined, metallothionein showed a significant down regulation in the radiation treated group (-3.85 fold) and a trend toward down regulation in the high Fe + rad group. Metallothionein is involved in the regulation of physiological metals and also has antioxidant activities. Among the drug metabolism genes examined, ATP binding cassette subfamily B (Abcb1b) gene expression increased more than 10-fold in both groups that received radiation treatments. This increased expression was also seen at the protein level. This ABC transporter carries many different compounds across cell membranes, including administered medications. The cytochrome P450 2E1 enzyme, a mixed-function oxidase that deactivates some medications and activates others, showed about a 2-fold increase in gene expression in both radiation-treated groups, with a trend toward increased expression at the protein level. Expression of epoxide hydrolase, which detoxifies polycyclic aromatic hydrocarbons, showed similar 2-fold increases. Among the DNA repair genes examined, expression of RAD51 was significantly down regulated (1.5 fold) in the radiation treated group. RAD51 is involved in repair of double-stranded DNA breaks. CONCLUSION This experiment used 2 different sources of physiological oxidative stress, administered separately and together, and examined their impacts on liver gene and protein expression. It is clear that significant changes occurred in expression of several genes and proteins in the radiation-treated animals. If the results from this ground analog of portions of the spaceflight environment hold true for the spaceflight environment itself, the physiological roles of the affected enzymes (drug transport and metabolism, redox homeostasis) could mean consequences in redox homeostasis or the pharmacokinetics of administered medications

  16. Pharmacogenetics of drug-metabolizing enzymes in US Hispanics

    PubMed Central

    Duconge, Jorge; Cadilla, Carmen L.; Ruaño, Gualberto

    2015-01-01

    Although the Hispanic population is continuously growing in the United States, they are underrepresented in pharmacogenetic studies. This review addresses the need for compiling available pharmacogenetic data in US Hispanics, discussing the prevalence of clinically relevant polymorphisms in pharmacogenes encoding for drug-metabolizing enzymes. CYP3A5*3 (0.245–0.867) showed the largest frequency in a US Hispanic population. A higher prevalence of CYP2C9*3, CYP2C19*4, and UGT2B7 IVS1+985 A>Gwas observed in US Hispanic vs. non-Hispanic populations. We found interethnic and intraethnic variability in frequencies of genetic polymorphisms for metabolizing enzymes, which highlights the need to define the ancestries of participants in pharmacogenetic studies. New approaches should be integrated in experimental designs to gain knowledge about the clinical relevance of the unique combination of genetic variants occurring in this admixed population. Ethnic subgroups in the US Hispanic population may harbor variants that might be part of multiple causative loci or in linkage-disequilibrium with functional variants. Pharmacogenetic studies in Hispanics should not be limited to ascertain commonly studied polymorphisms that were originally identified in their parental populations. The success of the Personalized Medicine paradigm will depend on recognizing genetic diversity between and within US Hispanics and the uniqueness of their genetic backgrounds. PMID:25431893

  17. Isotopic labeling affects 1,25-dihydroxyvitamin D metabolism

    SciTech Connect

    Halloran, B.P.; Bikle, D.D.; Castro, M.E.; Gee, E.

    1989-02-07

    Isotope substitution can change the biochemical properties of vitamin D. To determine the effect of substituting 3H for 1H on the metabolism of 1,25(OH)2D3, we measured the metabolic clearance rate and renal metabolism of unlabeled and 3H-labeled 1,25(OH)2D3. Substitution of 3H for 1H on carbons 26 and 27 (1,25(OH)2(26,27(n)-3H)D3) or on carbons 23 and 24 (1,25(OH)2(23,24(n)-3H)D3) reduced the in vivo metabolic clearance rate of 1,25(OH)2D3 by 36% and 37%, respectively, and reduced the in vitro renal catabolism of 1,25(OH)2D3 by 11% and 54%, respectively. Substitutions of 3H for 1H on carbons 23 and 24 as opposed to carbons 26 and 27 reduced conversion of (3H)1,25(OH)2D3 to (3H)1,24,25(OH)2D3 by 25% and to putative 24-oxo-1,23,25-dihydroxyvitamin D3 by 1600%. These results indicate that substitution of 3H for 1H on carbons 26 and 27 or on carbons 23 and 24 can reduce the metabolic clearance rate and in vitro metabolism of 1,25(OH)2D3 and quantitatively alter the pattern of metabolic products produced.

  18. 78 FR 64956 - Endocrinologic and Metabolic Drugs Advisory Committee; Notice of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-30

    ... HUMAN SERVICES Food and Drug Administration Endocrinologic and Metabolic Drugs Advisory Committee; Notice of Meeting AGENCY: Food and Drug Administration, HHS. ACTION: Notice. This notice announces a forthcoming meeting of a public advisory committee of the Food and Drug Administration (FDA). The meeting...

  19. Targeted fluorination of a nonsteroidal anti-inflammatory drug to prolong metabolic half-life.

    PubMed

    Shaughnessy, Maxwell J; Harsanyi, Antal; Li, Jingji; Bright, Tara; Murphy, Cormac D; Sandford, Graham

    2014-04-01

    In drug design, one way of improving metabolic stability is to introduce fluorine at a metabolically labile site. In the early stages of drug design, identification of such sites is challenging, and a rapid method of assessing the effect of fluorination on a putative drug's metabolic stability would be of clear benefit. One approach to this is to employ micro-organisms that are established as models of drug metabolism in parallel with the synthesis of fluorinated drug analogues. In this study, we have used the filamentous fungus Cunninghamella elegans to identify the metabolically labile site of the nonsteroidal anti-inflammatory drug flurbiprofen, to aid in the design of fluorinated derivatives that were subsequently synthesised. The effect of the additional fluorine substitution on cytochrome P450-catalysed oxidation was then determined via incubation with the fungus, and demonstrated that fluorine substitution at the 4'-position rendered the drug inactive to oxidative transformation, whereas substitution of fluorine at either 2' or 3' resulted in slower oxidation compared to the original drug. This approach to modulating the metabolic stability of a drug-like compound is widely applicable and can be used to address metabolic issues of otherwise good lead compounds in drug development.

  20. Gene duplication and divergence affecting drug content in Cannabis sativa.

    PubMed

    Weiblen, George D; Wenger, Jonathan P; Craft, Kathleen J; ElSohly, Mahmoud A; Mehmedic, Zlatko; Treiber, Erin L; Marks, M David

    2015-12-01

    Cannabis sativa is an economically important source of durable fibers, nutritious seeds, and psychoactive drugs but few economic plants are so poorly understood genetically. Marijuana and hemp were crossed to evaluate competing models of cannabinoid inheritance and to explain the predominance of tetrahydrocannabinolic acid (THCA) in marijuana compared with cannabidiolic acid (CBDA) in hemp. Individuals in the resulting F2 population were assessed for differential expression of cannabinoid synthase genes and were used in linkage mapping. Genetic markers associated with divergent cannabinoid phenotypes were identified. Although phenotypic segregation and a major quantitative trait locus (QTL) for the THCA/CBDA ratio were consistent with a simple model of codominant alleles at a single locus, the diversity of THCA and CBDA synthase sequences observed in the mapping population, the position of enzyme coding loci on the map, and patterns of expression suggest multiple linked loci. Phylogenetic analysis further suggests a history of duplication and divergence affecting drug content. Marijuana is distinguished from hemp by a nonfunctional CBDA synthase that appears to have been positively selected to enhance psychoactivity. An unlinked QTL for cannabinoid quantity may also have played a role in the recent escalation of drug potency. PMID:26189495

  1. Gene duplication and divergence affecting drug content in Cannabis sativa.

    PubMed

    Weiblen, George D; Wenger, Jonathan P; Craft, Kathleen J; ElSohly, Mahmoud A; Mehmedic, Zlatko; Treiber, Erin L; Marks, M David

    2015-12-01

    Cannabis sativa is an economically important source of durable fibers, nutritious seeds, and psychoactive drugs but few economic plants are so poorly understood genetically. Marijuana and hemp were crossed to evaluate competing models of cannabinoid inheritance and to explain the predominance of tetrahydrocannabinolic acid (THCA) in marijuana compared with cannabidiolic acid (CBDA) in hemp. Individuals in the resulting F2 population were assessed for differential expression of cannabinoid synthase genes and were used in linkage mapping. Genetic markers associated with divergent cannabinoid phenotypes were identified. Although phenotypic segregation and a major quantitative trait locus (QTL) for the THCA/CBDA ratio were consistent with a simple model of codominant alleles at a single locus, the diversity of THCA and CBDA synthase sequences observed in the mapping population, the position of enzyme coding loci on the map, and patterns of expression suggest multiple linked loci. Phylogenetic analysis further suggests a history of duplication and divergence affecting drug content. Marijuana is distinguished from hemp by a nonfunctional CBDA synthase that appears to have been positively selected to enhance psychoactivity. An unlinked QTL for cannabinoid quantity may also have played a role in the recent escalation of drug potency.

  2. Prenatal hyperandrogenism induces alterations that affect liver lipid metabolism.

    PubMed

    Abruzzese, Giselle Adriana; Heber, Maria Florencia; Ferreira, Silvana Rocio; Velez, Leandro Martin; Reynoso, Roxana; Pignataro, Omar Pedro; Motta, Alicia Beatriz

    2016-07-01

    Prenatal hyperandrogenism is hypothesized as one of the main factors contributing to the development of polycystic ovary syndrome (PCOS). PCOS patients have high risk of developing fatty liver and steatosis. This study aimed to evaluate the role of prenatal hyperandrogenism in liver lipid metabolism and fatty liver development. Pregnant rats were hyperandrogenized with testosterone. At pubertal age, the prenatally hyperandrogenized (PH) female offspring displayed both ovulatory (PHov) and anovulatory (PHanov) phenotypes that mimic human PCOS features. We evaluated hepatic transferases, liver lipid content, the balance between lipogenesis and fatty acid oxidation pathway, oxidant/antioxidant balance and proinflammatory status. We also evaluated the general metabolic status through growth rate curve, basal glucose and insulin levels, glucose tolerance test, HOMA-IR index and serum lipid profile. Although neither PH group showed signs of liver lipid content, the lipogenesis and fatty oxidation pathways were altered. The PH groups also showed impaired oxidant/antioxidant balance, a decrease in the proinflammatory pathway (measured by prostaglandin E2 and cyclooxygenase-2 levels), decreased glucose tolerance, imbalance of circulating lipids and increased risk of metabolic syndrome. We conclude that prenatal hyperandrogenism generates both PHov and PHanov phenotypes with signs of liver alterations, imbalance in lipid metabolism and increased risk of developing metabolic syndrome. The anovulatory phenotype showed more alterations in liver lipogenesis and a more impaired balance of insulin and glucose metabolism, being more susceptible to the development of steatosis.

  3. How does metabolism affect cell death in cancer?

    PubMed

    Villa, Elodie; Ricci, Jean-Ehrland

    2016-07-01

    In cancer research, identifying a specificity of tumor cells compared with 'normal' proliferating cells for targeted therapy is often considered the Holy Grail for researchers and clinicians. Although diverse in origin, most cancer cells share characteristics including the ability to escape cell death mechanisms and the utilization of different methods of energy production. In the current paradigm, aerobic glycolysis is considered the central metabolic characteristic of cancer cells (Warburg effect). However, recent data indicate that cancer cells also show significant changes in other metabolic pathways. Indeed, it was recently suggested that Kreb's cycle, pentose phosphate pathway intermediates, and essential and nonessential amino acids have key roles. Renewed interest in the fact that cancer cells have to reprogram their metabolism in order to proliferate or resist treatment must take into consideration the ability of tumor cells to adapt their metabolism to the local microenvironment (low oxygen, low nutrients). This variety of metabolic sources might be either a strength, resulting in infinite possibilities for adaptation and increased ability to resist chemotherapy-induced death, or a weakness that could be targeted to kill cancer cells. Here, we discuss recent insights showing how energetic metabolism may regulate cell death and how this might be relevant for cancer treatment.

  4. Exposure to gemfibrozil and atorvastatin affects cholesterol metabolism and steroid production in zebrafish (Danio rerio).

    PubMed

    Al-Habsi, Aziz A; Massarsky, Andrey; Moon, Thomas W

    2016-09-01

    The commonly used lipid-lowering pharmaceuticals gemfibrozil (GEM) and atorvastatin (ATV) are detected in the aquatic environment; however, their potential effects on non-target fish species are yet to be fully understood. This study examined the effects of GEM and/or ATV on female and male adult zebrafish after a 30d dietary exposure. The exposure led to changes in several biochemical parameters, including reduction in cholesterol, triglycerides, cortisol, testosterone, and estradiol. Changes in cholesterol and triglycerides were also associated with changes in transcript levels of key genes involved with cholesterol and lipid regulation, including SREBP2, HMGCR1, PPARα, and SREBP1. We also noted higher CYP3A65 and atrogin1 mRNA levels in drug-treated male fish. Sex differences were apparent in some of the examined parameters at both biochemical and molecular levels. This study supports these drugs affecting cholesterol metabolism and steroid production in adult zebrafish. We conclude that the reduction in cortisol may impair the ability of these fish to mount a suitable stress response, whereas the reduction of sex steroids may negatively affect reproduction. PMID:26627126

  5. Exposure to gemfibrozil and atorvastatin affects cholesterol metabolism and steroid production in zebrafish (Danio rerio).

    PubMed

    Al-Habsi, Aziz A; Massarsky, Andrey; Moon, Thomas W

    2016-09-01

    The commonly used lipid-lowering pharmaceuticals gemfibrozil (GEM) and atorvastatin (ATV) are detected in the aquatic environment; however, their potential effects on non-target fish species are yet to be fully understood. This study examined the effects of GEM and/or ATV on female and male adult zebrafish after a 30d dietary exposure. The exposure led to changes in several biochemical parameters, including reduction in cholesterol, triglycerides, cortisol, testosterone, and estradiol. Changes in cholesterol and triglycerides were also associated with changes in transcript levels of key genes involved with cholesterol and lipid regulation, including SREBP2, HMGCR1, PPARα, and SREBP1. We also noted higher CYP3A65 and atrogin1 mRNA levels in drug-treated male fish. Sex differences were apparent in some of the examined parameters at both biochemical and molecular levels. This study supports these drugs affecting cholesterol metabolism and steroid production in adult zebrafish. We conclude that the reduction in cortisol may impair the ability of these fish to mount a suitable stress response, whereas the reduction of sex steroids may negatively affect reproduction.

  6. Resveratrol modulates drug- and carcinogen-metabolizing enzymes in a healthy volunteer study.

    PubMed

    Chow, H-H Sherry; Garland, Linda L; Hsu, Chiu-Hsieh; Vining, Donna R; Chew, Wade M; Miller, Jessica A; Perloff, Marjorie; Crowell, James A; Alberts, David S

    2010-09-01

    Resveratrol has been shown to exhibit cancer-preventive activities in preclinical studies. We conducted a clinical study to determine the effect of pharmacologic doses of resveratrol on drug- and carcinogen-metabolizing enzymes. Forty-two healthy volunteers underwent baseline assessment of cytochrome P450 (CYP) and phase II detoxification enzymes. CYP1A2, CYP2D6, CYP2C9, and CYP3A4 enzyme activities were measured by the metabolism of caffeine, dextromethorphan, losartan, and buspirone, respectively. Blood lymphocyte glutathione S-transferase (GST) activity and GST-pi level and serum total and direct bilirubin, a surrogate for UDP-glucuronosyl transferase (UGT) 1A1 activity, were measured to assess phase II enzymes. After the baseline evaluation, study participants took 1 g of resveratrol once daily for 4 weeks. Enzyme assessment was repeated upon intervention completion. Resveratrol intervention was found to inhibit the phenotypic indices of CYP3A4, CYP2D6, and CYP2C9 and to induce the phenotypic index of 1A2. Overall, GST and UGT1A1 activities were minimally affected by the intervention, although an induction of GST-pi level and UGT1A1 activity was observed in individuals with low baseline enzyme level/activity. We conclude that resveratrol can modulate enzyme systems involved in carcinogen activation and detoxification, which may be one mechanism by which resveratrol inhibits carcinogenesis. However, pharmacologic doses of resveratrol could potentially lead to increased adverse drug reactions or altered drug efficacy due to inhibition or induction of certain CYPs. Further clinical development of resveratrol for cancer prevention should consider evaluation of lower doses of resveratrol to minimize adverse metabolic drug interactions. PMID:20716633

  7. Antihypertensive Drugs Metabolism: An Update to Pharmacokinetic Profiles and Computational Approaches

    PubMed Central

    Zisaki, Aikaterini; Miskovic, Ljubisa; Hatzimanikatis, Vassily

    2015-01-01

    Drug discovery and development is a high-risk enterprise that requires significant investments in capital, time and scientific expertise. The studies of xenobiotic metabolism remain as one of the main topics in the research and development of drugs, cosmetics and nutritional supplements. Antihypertensive drugs are used for the treatment of high blood pressure, which is one the most frequent symptoms of the patients that undergo cardiovascular diseases such as myocardial infraction and strokes. In current cardiovascular disease pharmacology, four drug clusters - Angiotensin Converting Enzyme Inhibitors, Beta-Blockers, Calcium Channel Blockers and Diuretics - cover the major therapeutic characteristics of the most antihypertensive drugs. The pharmacokinetic and specifically the metabolic profile of the antihypertensive agents are intensively studied because of the broad inter-individual variability on plasma concentrations and the diversity on the efficacy response especially due to the P450 dependent metabolic status they present. Several computational methods have been developed with the aim to: (i) model and better understand the human drug metabolism; and (ii) enhance the experimental investigation of the metabolism of small xenobiotic molecules. The main predictive tools these methods employ are rule-based approaches, quantitative structure metabolism/activity relationships and docking approaches. This review paper provides detailed metabolic profiles of the major clusters of antihypertensive agents, including their metabolites and their metabolizing enzymes, and it also provides specific information concerning the computational approaches that have been used to predict the metabolic profile of several antihypertensive drugs. PMID:25341854

  8. Drug Metabolizing Enzyme and Transporter Gene Variation, Nicotine Metabolism, Prospective Abstinence, and Cigarette Consumption.

    PubMed

    Bergen, Andrew W; Michel, Martha; Nishita, Denise; Krasnow, Ruth; Javitz, Harold S; Conneely, Karen N; Lessov-Schlaggar, Christina N; Hops, Hyman; Zhu, Andy Z X; Baurley, James W; McClure, Jennifer B; Hall, Sharon M; Baker, Timothy B; Conti, David V; Benowitz, Neal L; Lerman, Caryn; Tyndale, Rachel F; Swan, Gary E

    2015-01-01

    The Nicotine Metabolite Ratio (NMR, ratio of trans-3'-hydroxycotinine and cotinine), has previously been associated with CYP2A6 activity, response to smoking cessation treatments, and cigarette consumption. We searched for drug metabolizing enzyme and transporter (DMET) gene variation associated with the NMR and prospective abstinence in 2,946 participants of laboratory studies of nicotine metabolism and of clinical trials of smoking cessation therapies. Stage I was a meta-analysis of the association of 507 common single nucleotide polymorphisms (SNPs) at 173 DMET genes with the NMR in 449 participants of two laboratory studies. Nominally significant associations were identified in ten genes after adjustment for intragenic SNPs; CYP2A6 and two CYP2A6 SNPs attained experiment-wide significance adjusted for correlated SNPs (CYP2A6 PACT=4.1E-7, rs4803381 PACT=4.5E-5, rs1137115, PACT=1.2E-3). Stage II was mega-regression analyses of 10 DMET SNPs with pretreatment NMR and prospective abstinence in up to 2,497 participants from eight trials. rs4803381 and rs1137115 SNPs were associated with pretreatment NMR at genome-wide significance. In post-hoc analyses of CYP2A6 SNPs, we observed nominally significant association with: abstinence in one pharmacotherapy arm; cigarette consumption among all trial participants; and lung cancer in four case:control studies. CYP2A6 minor alleles were associated with reduced NMR, CPD, and lung cancer risk. We confirmed the major role that CYP2A6 plays in nicotine metabolism, and made novel findings with respect to genome-wide significance and associations with CPD, abstinence and lung cancer risk. Additional multivariate analyses with patient variables and genetic modeling will improve prediction of nicotine metabolism, disease risk and smoking cessation treatment prognosis. PMID:26132489

  9. Drug Metabolizing Enzyme and Transporter Gene Variation, Nicotine Metabolism, Prospective Abstinence, and Cigarette Consumption.

    PubMed

    Bergen, Andrew W; Michel, Martha; Nishita, Denise; Krasnow, Ruth; Javitz, Harold S; Conneely, Karen N; Lessov-Schlaggar, Christina N; Hops, Hyman; Zhu, Andy Z X; Baurley, James W; McClure, Jennifer B; Hall, Sharon M; Baker, Timothy B; Conti, David V; Benowitz, Neal L; Lerman, Caryn; Tyndale, Rachel F; Swan, Gary E

    2015-01-01

    The Nicotine Metabolite Ratio (NMR, ratio of trans-3'-hydroxycotinine and cotinine), has previously been associated with CYP2A6 activity, response to smoking cessation treatments, and cigarette consumption. We searched for drug metabolizing enzyme and transporter (DMET) gene variation associated with the NMR and prospective abstinence in 2,946 participants of laboratory studies of nicotine metabolism and of clinical trials of smoking cessation therapies. Stage I was a meta-analysis of the association of 507 common single nucleotide polymorphisms (SNPs) at 173 DMET genes with the NMR in 449 participants of two laboratory studies. Nominally significant associations were identified in ten genes after adjustment for intragenic SNPs; CYP2A6 and two CYP2A6 SNPs attained experiment-wide significance adjusted for correlated SNPs (CYP2A6 PACT=4.1E-7, rs4803381 PACT=4.5E-5, rs1137115, PACT=1.2E-3). Stage II was mega-regression analyses of 10 DMET SNPs with pretreatment NMR and prospective abstinence in up to 2,497 participants from eight trials. rs4803381 and rs1137115 SNPs were associated with pretreatment NMR at genome-wide significance. In post-hoc analyses of CYP2A6 SNPs, we observed nominally significant association with: abstinence in one pharmacotherapy arm; cigarette consumption among all trial participants; and lung cancer in four case:control studies. CYP2A6 minor alleles were associated with reduced NMR, CPD, and lung cancer risk. We confirmed the major role that CYP2A6 plays in nicotine metabolism, and made novel findings with respect to genome-wide significance and associations with CPD, abstinence and lung cancer risk. Additional multivariate analyses with patient variables and genetic modeling will improve prediction of nicotine metabolism, disease risk and smoking cessation treatment prognosis.

  10. Drug Metabolizing Enzyme and Transporter Gene Variation, Nicotine Metabolism, Prospective Abstinence, and Cigarette Consumption

    PubMed Central

    Bergen, Andrew W.; Michel, Martha; Nishita, Denise; Krasnow, Ruth; Javitz, Harold S.; Conneely, Karen N.; Lessov-Schlaggar, Christina N.; Hops, Hyman; Zhu, Andy Z. X.; Baurley, James W.; McClure, Jennifer B.; Hall, Sharon M.; Baker, Timothy B.; Conti, David V.; Benowitz, Neal L.; Lerman, Caryn; Tyndale, Rachel F.; Swan, Gary E.

    2015-01-01

    The Nicotine Metabolite Ratio (NMR, ratio of trans-3’-hydroxycotinine and cotinine), has previously been associated with CYP2A6 activity, response to smoking cessation treatments, and cigarette consumption. We searched for drug metabolizing enzyme and transporter (DMET) gene variation associated with the NMR and prospective abstinence in 2,946 participants of laboratory studies of nicotine metabolism and of clinical trials of smoking cessation therapies. Stage I was a meta-analysis of the association of 507 common single nucleotide polymorphisms (SNPs) at 173 DMET genes with the NMR in 449 participants of two laboratory studies. Nominally significant associations were identified in ten genes after adjustment for intragenic SNPs; CYP2A6 and two CYP2A6 SNPs attained experiment-wide significance adjusted for correlated SNPs (CYP2A6 PACT=4.1E-7, rs4803381 PACT=4.5E-5, rs1137115, PACT=1.2E-3). Stage II was mega-regression analyses of 10 DMET SNPs with pretreatment NMR and prospective abstinence in up to 2,497 participants from eight trials. rs4803381 and rs1137115 SNPs were associated with pretreatment NMR at genome-wide significance. In post-hoc analyses of CYP2A6 SNPs, we observed nominally significant association with: abstinence in one pharmacotherapy arm; cigarette consumption among all trial participants; and lung cancer in four case:control studies. CYP2A6 minor alleles were associated with reduced NMR, CPD, and lung cancer risk. We confirmed the major role that CYP2A6 plays in nicotine metabolism, and made novel findings with respect to genome-wide significance and associations with CPD, abstinence and lung cancer risk. Additional multivariate analyses with patient variables and genetic modeling will improve prediction of nicotine metabolism, disease risk and smoking cessation treatment prognosis. PMID:26132489

  11. Progress in drug development for Alzheimer's disease: An overview in relation to mitochondrial energy metabolism.

    PubMed

    Hroudová, Jana; Singh, Namrata; Fišar, Zdeněk; Ghosh, Kallol K

    2016-10-01

    Current possibilities of Alzheimer's disease (AD) treatment are very limited and are based on administration of cholinesterase inhibitors (donepezil, rivastigmine, galantamine) and/or N-methyl-d-aspartate receptor antagonist, memantine. Newly synthesized drugs affect multiple AD pathophysiological pathways and can act as inhibitors of cholinesterases (AChE, BuChE), inhibitors of monoamine oxidases (MAO-A, MAO-B), modulators of mitochondrial permeability transition pores, modulators of amyloid-beta binding alcohol dehydrogenase and antioxidants. Effects of clinically used as well as newly developed AD drugs were studied in relation to energy metabolism and mitochondrial functions, including oxidative phosphorylation, activities of enzymes of citric acid cycle or electron transfer system, mitochondrial membrane potential, calcium homeostasis, production of reactive oxygen species and MAO activity. PMID:27094132

  12. Fusidic Acid Inhibits Hepatic Transporters and Metabolic Enzymes: Potential Cause of Clinical Drug-Drug Interaction Observed with Statin Coadministration.

    PubMed

    Gupta, Anshul; Harris, Jennifer J; Lin, Jianrong; Bulgarelli, James P; Birmingham, Bruce K; Grimm, Scott W

    2016-10-01

    Fusidic acid (FA), which was approved in the 1960s in many European and Asian countries, has gained renewed interest due to its continued effectiveness against methicillin-resistant Staphylococcus aureus As rhabdomyolysis has been reported upon coadministration of FA with statins, we aimed to elucidate the underlying molecular mechanisms that contribute to FA-statin drug-drug interactions. Because of the association between rhabdomyolysis and increased exposure to statins, we investigated if cytochrome P450 (CYP) enzymes and transporters involved in the disposition of various statins are inhibited by FA. FA was found to inhibit BCRP and OATP1B1 but not P-gp. In overexpressing cell systems, FA inhibited BCRP-mediated efflux (50% inhibitory concentration [IC50], ∼50 to 110 μM) and OATP1B1-mediated uptake (IC50, ∼4 to 35 μM) of statins at clinically relevant concentrations achievable in the intestine and liver (based on a 550-mg oral dose of FA, the expected maximum theoretical gastrointestinal concentration is ∼4 mM, and the maximum total or unbound concentration in the inlet to the liver was reported to be up to 223 μM or 11 μM, respectively, upon multiple dosing). Similarly, FA inhibited metabolism of statins in human liver microsomes (IC50, ∼17 to 195 μM). These data suggest that FA inhibits at least 3 major dispositional pathways (BCRP, OATP1B1, and CYP3A) and thus affects the clearance of several statins. We confirmed that FA is eliminated via phase 1 metabolism (primarily via CYP3A); however, there is also some phase 2 metabolism (mediated primarily by UGT1A1). Taken together, these data provide evidence for molecular mechanisms that may explain the occurrence of rhabdomyolysis when FA is administered with statins.

  13. Effect of praseodymium on drug metabolism in rat liver smooth and rough endoplasmic reticulum.

    PubMed

    Arvela, P; von Lehmann, B; Grajewski, O; Oberdisse, E

    1980-07-15

    A small i.v. dose (3 mg/kg) of a light lanthanon, praseodymium, impairs the drug metabolizing capacity of both the smooth and rough fractions of rat liver endoplasmic reticulum. This decrease in the activity of drug metabolizing enzymes and in the amount of cytochromes P-450 and b5 is more pronounced in the rough endoplasmic reticulum fraction.

  14. Evaluation of a New Molecular Entity as a Victim of Metabolic Drug-Drug Interactions-an Industry Perspective.

    PubMed

    Bohnert, Tonika; Patel, Aarti; Templeton, Ian; Chen, Yuan; Lu, Chuang; Lai, George; Leung, Louis; Tse, Susanna; Einolf, Heidi J; Wang, Ying-Hong; Sinz, Michael; Stearns, Ralph; Walsky, Robert; Geng, Wanping; Sudsakorn, Sirimas; Moore, David; He, Ling; Wahlstrom, Jan; Keirns, Jim; Narayanan, Rangaraj; Lang, Dieter; Yang, Xiaoqing

    2016-08-01

    Under the guidance of the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ), scientists from 20 pharmaceutical companies formed a Victim Drug-Drug Interactions Working Group. This working group has conducted a review of the literature and the practices of each company on the approaches to clearance pathway identification (fCL), estimation of fractional contribution of metabolizing enzyme toward metabolism (fm), along with modeling and simulation-aided strategy in predicting the victim drug-drug interaction (DDI) liability due to modulation of drug metabolizing enzymes. Presented in this perspective are the recommendations from this working group on: 1) strategic and experimental approaches to identify fCL and fm, 2) whether those assessments may be quantitative for certain enzymes (e.g., cytochrome P450, P450, and limited uridine diphosphoglucuronosyltransferase, UGT enzymes) or qualitative (for most of other drug metabolism enzymes), and the impact due to the lack of quantitative information on the latter. Multiple decision trees are presented with stepwise approaches to identify specific enzymes that are involved in the metabolism of a given drug and to aid the prediction and risk assessment of drug as a victim in DDI. Modeling and simulation approaches are also discussed to better predict DDI risk in humans. Variability and parameter sensitivity analysis were emphasized when applying modeling and simulation to capture the differences within the population used and to characterize the parameters that have the most influence on the prediction outcome. PMID:27052879

  15. Neoadjuvant Window Studies of Metformin and Biomarker Development for Drugs Targeting Cancer Metabolism.

    PubMed

    Lord, Simon R; Patel, Neel; Liu, Dan; Fenwick, John; Gleeson, Fergus; Buffa, Francesca; Harris, Adrian L

    2015-05-01

    There has been growing interest in the potential of the altered metabolic state typical of cancer cells as a drug target. The antidiabetes drug, metformin, is now under intense investigation as a safe method to modify cancer metabolism. Several studies have used window of opportunity in breast cancer patients before neoadjuvant chemotherapy to correlate gene expression analysis, metabolomics, immunohistochemical markers, and metabolic serum markers with those likely to benefit. We review the role metabolite measurement, functional imaging and gene sequencing analysis play in elucidating the effects of metabolically targeted drugs in cancer treatment and determining patient selection. PMID:26063894

  16. Predicting Drug Extraction in the Human Gut Wall: Assessing Contributions from Drug Metabolizing Enzymes and Transporter Proteins using Preclinical Models.

    PubMed

    Peters, Sheila Annie; Jones, Christopher R; Ungell, Anna-Lena; Hatley, Oliver J D

    2016-06-01

    Intestinal metabolism can limit oral bioavailability of drugs and increase the risk of drug interactions. It is therefore important to be able to predict and quantify it in drug discovery and early development. In recent years, a plethora of models-in vivo, in situ and in vitro-have been discussed in the literature. The primary objective of this review is to summarize the current knowledge in the quantitative prediction of gut-wall metabolism. As well as discussing the successes of current models for intestinal metabolism, the challenges in the establishment of good preclinical models are highlighted, including species differences in the isoforms; regional abundances and activities of drug metabolizing enzymes; the interplay of enzyme-transporter proteins; and lack of knowledge on enzyme abundances and availability of empirical scaling factors. Due to its broad specificity and high abundance in the intestine, CYP3A is the enzyme that is frequently implicated in human gut metabolism and is therefore the major focus of this review. A strategy to assess the impact of gut wall metabolism on oral bioavailability during drug discovery and early development phases is presented. Current gaps in the mechanistic understanding and the prediction of gut metabolism are highlighted, with suggestions on how they can be overcome in the future.

  17. Review of current chemoinformatic tools for modeling important aspects of CYPs-mediated drug metabolism. Integrating metabolism data with other biological profiles to enhance drug discovery.

    PubMed

    Speck-Planche, Alejandro; Cordeiro, Maria Natalia Dias Soeiro

    2014-01-01

    The study of the metabolism of xenobiotics by the human body is an essential stage in the complex and expensive process of drug discovery, being one of the main causes of disapproval and/or withdrawal of drugs. Regarding this, enzymes known as cytochromes P450 (CYPs) play a very decisive role in the biotransformation of many chemicals. For this reason, the use of chemoinformatics to predict and /or analyze from different points of view CYPs-mediated drug metabolism, can help to reduce time and financial resources. This work is focused on the most remarkable advances in the last 5 years of the chemoinformatics tools towards the virtual analysis of CYPsmediated drug metabolism. First, a brief section is dedicated to the applicability of chemoinformatics in different areas associated with drug metabolism. Then, both the models for prediction of CYPs substrates and those allowing the assessment of sites of metabolism (SOM) are discussed. At the same time, the principal limitations of the current chemoinformatic tools are pointed out. Finally, and taking into account that metabolism is an essential step in the whole process of designing any drug, we introduce here as a case of study, the first multitasking model for quantitative-structure biological effect relationships (mtk-QSBER). The purpose of this model is to integrate different types of biological profiles such as ADMET (absorption, distribution, metabolism, excretion, toxicity) profiles and antistaphylococci activities. The mtk-QSBER model was created by employing a heterogeneous dataset of more than 66000 cases tested in 6510 different experimental conditions. The model displayed a total accuracy higher than 94%. To the best of our knowledge, this is the first attempt to complement metabolism assays with other relevant biological data in order to speed up the discovery of efficacious antistaphylococci agents. PMID:24909424

  18. Natural toxins that affect plant amino acid metabolism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A diverse range of natural compounds interfere with the synthesis and other aspects of amino acid metabolism. Some are amino acid analogues, but most are not. This review covers a number of specific natural phytotoxic compounds by molecular target site. Inhibition of glutamine synthetase is of part...

  19. Arylamine N-acetyltransferases: from drug metabolism and pharmacogenetics to drug discovery

    PubMed Central

    Sim, E; Abuhammad, A; Ryan, A

    2014-01-01

    Arylamine N-acetyltransferases (NATs) are polymorphic drug-metabolizing enzymes, acetylating arylamine carcinogens and drugs including hydralazine and sulphonamides. The slow NAT phenotype increases susceptibility to hydralazine and isoniazid toxicity and to occupational bladder cancer. The two polymorphic human NAT loci show linkage disequilibrium. All mammalian Nat genes have an intronless open reading frame and non-coding exons. The human gene products NAT1 and NAT2 have distinct substrate specificities: NAT2 acetylates hydralazine and human NAT1 acetylates p-aminosalicylate (p-AS) and the folate catabolite para-aminobenzoylglutamate (p-abaglu). Human NAT2 is mainly in liver and gut. Human NAT1 and its murine homologue are in many adult tissues and in early embryos. Human NAT1 is strongly expressed in oestrogen receptor-positive breast cancer and may contribute to folate and acetyl CoA homeostasis. NAT enzymes act through a catalytic triad of Cys, His and Asp with the architecture of the active site-modulating specificity. Polymorphisms may cause unfolded protein. The C-terminus helps bind acetyl CoA and differs among NATs including prokaryotic homologues. NAT in Salmonella typhimurium supports carcinogen activation and NAT in mycobacteria metabolizes isoniazid with polymorphism a minor factor in isoniazid resistance. Importantly, nat is in a gene cluster essential for Mycobacterium tuberculosis survival inside macrophages. NAT inhibitors are a starting point for novel anti-tuberculosis drugs. Human NAT1-specific inhibitors may act in biomarker detection in breast cancer and in cancer therapy. NAT inhibitors for co-administration with 5-aminosalicylate (5-AS) in inflammatory bowel disease has prompted ongoing investigations of azoreductases in gut bacteria which release 5-AS from prodrugs including balsalazide. PMID:24467436

  20. Fusion and metabolism of plant cells as affected by microgravity.

    PubMed

    Hampp, R; Hoffmann, E; Schönherr, K; Johann, P; De Filippis, L

    1997-01-01

    Plant cell protoplasts derived from leaf tissue of two different tobacco species (Nicotiana tabacum., N. rustica L.) were exposed to short-term (sounding rocket experiments) and long-term (spacelab) microgravity environments in order to study both (electro) cell fusion and cell metabolism during early and later stages of tissue regeneration. The period of exposure to microgravity varied from 10 min (sounding rocket) to 10 d (space shuttle). The process of electro fusion of protoplasts was improved under conditions of microgravity: the time needed to establish close membrane contact between protoplasts (alignment time) was reduced (5 as compared to 15 s under 1 g) and numbers of fusion products between protoplasts of different specific density were increased by a factor of about 10. In addition, viability of fusion products, as shown by the ability to form callus, increased from about 60% to more than 90%. Regenerated fusion products obtained from both sounding-rocket and spacelab experiments showed a wide range of intermediate properties between the two parental plants. This was verified by isozyme analysis and random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). In order to address potential metabolic responses, more general markers such as the overall energy state (ATP/ADP ratio), the redox charge of the diphosphopyridine nucleotide system (NADH/NAD ratio), and the pool size of fructose-2,6-bisphosphate (Fru 2,6 bisp), a regulator of the balance between glycolysis and gluconeogenesis, were determined. Responses of these parameters were different with regard to short-term and long-term exposure. Shortly after transition to reduced gravitation (sounding rocket) ratios of ATP/ADP exhibited strong fluctuation while the pool size of NAD decreased (indicating an increased NADH/NAD ratio) and that of Fru 2,6 bisp increased. As similar changes can be observed under stress conditions, this response is probably indicative of a metabolic stress

  1. Rewired metabolism in drug-resistant leukemia cells: a metabolic switch hallmarked by reduced dependence on exogenous glutamine.

    PubMed

    Stäubert, Claudia; Bhuiyan, Hasanuzzaman; Lindahl, Anna; Broom, Oliver Jay; Zhu, Yafeng; Islam, Saiful; Linnarsson, Sten; Lehtiö, Janne; Nordström, Anders

    2015-03-27

    Cancer cells that escape induction therapy are a major cause of relapse. Understanding metabolic alterations associated with drug resistance opens up unexplored opportunities for the development of new therapeutic strategies. Here, we applied a broad spectrum of technologies including RNA sequencing, global untargeted metabolomics, and stable isotope labeling mass spectrometry to identify metabolic changes in P-glycoprotein overexpressing T-cell acute lymphoblastic leukemia (ALL) cells, which escaped a therapeutically relevant daunorubicin treatment. We show that compared with sensitive ALL cells, resistant leukemia cells possess a fundamentally rewired central metabolism characterized by reduced dependence on glutamine despite a lack of expression of glutamate-ammonia ligase (GLUL), a higher demand for glucose and an altered rate of fatty acid β-oxidation, accompanied by a decreased pantothenic acid uptake capacity. We experimentally validate our findings by selectively targeting components of this metabolic switch, using approved drugs and starvation approaches followed by cell viability analyses in both the ALL cells and in an acute myeloid leukemia (AML) sensitive/resistant cell line pair. We demonstrate how comparative metabolomics and RNA expression profiling of drug-sensitive and -resistant cells expose targetable metabolic changes and potential resistance markers. Our results show that drug resistance is associated with significant metabolic costs in cancer cells, which could be exploited using new therapeutic strategies.

  2. Rewired metabolism in drug-resistant leukemia cells: a metabolic switch hallmarked by reduced dependence on exogenous glutamine.

    PubMed

    Stäubert, Claudia; Bhuiyan, Hasanuzzaman; Lindahl, Anna; Broom, Oliver Jay; Zhu, Yafeng; Islam, Saiful; Linnarsson, Sten; Lehtiö, Janne; Nordström, Anders

    2015-03-27

    Cancer cells that escape induction therapy are a major cause of relapse. Understanding metabolic alterations associated with drug resistance opens up unexplored opportunities for the development of new therapeutic strategies. Here, we applied a broad spectrum of technologies including RNA sequencing, global untargeted metabolomics, and stable isotope labeling mass spectrometry to identify metabolic changes in P-glycoprotein overexpressing T-cell acute lymphoblastic leukemia (ALL) cells, which escaped a therapeutically relevant daunorubicin treatment. We show that compared with sensitive ALL cells, resistant leukemia cells possess a fundamentally rewired central metabolism characterized by reduced dependence on glutamine despite a lack of expression of glutamate-ammonia ligase (GLUL), a higher demand for glucose and an altered rate of fatty acid β-oxidation, accompanied by a decreased pantothenic acid uptake capacity. We experimentally validate our findings by selectively targeting components of this metabolic switch, using approved drugs and starvation approaches followed by cell viability analyses in both the ALL cells and in an acute myeloid leukemia (AML) sensitive/resistant cell line pair. We demonstrate how comparative metabolomics and RNA expression profiling of drug-sensitive and -resistant cells expose targetable metabolic changes and potential resistance markers. Our results show that drug resistance is associated with significant metabolic costs in cancer cells, which could be exploited using new therapeutic strategies. PMID:25697355

  3. Scoparone affects lipid metabolism in primary hepatocytes using lipidomics

    PubMed Central

    Zhang, Aihua; Qiu, Shi; Sun, Hui; Zhang, Tianlei; Guan, Yu; Han, Ying; Yan, Guangli; Wang, Xijun

    2016-01-01

    Lipidomics, which focuses on the global study of molecular lipids in biological systems, could provide valuable insights about disease mechanisms. In this study, we present a nontargeted lipidomics strategy to determine cellular lipid alterations after scoparone exposure in primary hepatocytes. Lipid metabolic profiles were analyzed by high-performance liquid chromatography coupled with time-of-flight mass spectrometry, and a novel imaging TransOmics tool has been developed for the analysis of high-resolution MS data, including the data pretreatment, visualization, automated identification, deconvolution and quantification of lipid species. Chemometric and statistical analyses of the obtained lipid fingerprints revealed the global lipidomic alterations and tested the therapeutic effects of scoparone. Identification of ten proposed lipids contributed to the better understanding of the effects of scoparone on lipid metabolism in hepatocytes. The most striking finding was that scoparone caused comprehensive lipid changes, as represented by significant changes of the identificated lipids. The levels of identified PG(19:1(9Z)/14:0), PE(17:1(9Z)/0:0), PE(19:1(9Z)/0:0) were found to be upregulated in ethanol-induced group, whereas the levels in scoparone group were downregulated. Lipid metabolism in primary hepatocytes was changed significantly by scoparone treatment. We believe that this novel approach could substantially broaden the applications of high mass resolution mass spectrometry for cellular lipidomics. PMID:27306123

  4. Post-uptake metabolism affects quantification of amino acid uptake.

    PubMed

    Warren, Charles R

    2012-01-01

    • The quantitative significance of amino acids to plant nutrition remains controversial. This experiment determined whether post-uptake metabolism and root to shoot export differ between glycine and glutamine, and examined implications for estimation of amino acid uptake. • Field soil containing a Eucalyptus pauciflora seedling was injected with uniformly (13)C- and (15)N-labelled glycine or glutamine. I quantified (15)N and (13)C excess in leaves and roots and intact labelled amino acids in leaves, roots and stem xylem sap. A tunable diode laser quantified fluxes of (12)CO(2) and (13)CO(2) from leaves and soil. • 60-360 min after addition of amino acid, intact molecules of U-(13)C,(15)N glutamine were < 5% of (15)N excess in roots, whereas U-(13)C,(15)N glycine was 30-100% of (15)N excess in roots. Intact molecules of glutamine, but not glycine, were exported from roots to shoots. • Post-uptake metabolism and transport complicate interpretation of isotope labelling such that root and shoot contents of intact amino acid, (13)C and (15)N may not reflect rates of uptake. Future experiments should focus on reconciling discrepancies between intact amino acid, (13)C and (15)N by determining the turnover of amino acids within roots. Alternatively, post-uptake metabolism and transport could be minimized by harvesting plants within minutes of isotope addition.

  5. Environmental factors affecting indole metabolism under anaerobic conditions.

    PubMed Central

    Madsen, E L; Francis, A J; Bollag, J M

    1988-01-01

    The influence of physiological and environmental factors on the accumulation of oxindole during anaerobic indole metabolism was investigated by high-performance liquid chromatography. Under methanogenic conditions, indole was temporarily converted to oxindole in stoichiometric amounts in media inoculated with three freshwater sediments and an organic soil. In media inoculated with methanogenic sewage sludge, the modest amounts of oxindole detected at 35 degrees C reached higher concentrations and persisted longer when the incubation temperature was decreased from 35 to 15 degrees C. Also, decreasing the concentration of sewage sludge used as an inoculum from 50 to 1% caused an increase in the accumulation of oxindole from 10 to 75% of the indole added. Under denitrifying conditions, regardless of the concentration or source of the inoculum, oxindole appeared in trace amounts but did not accumulate during indole metabolism. In addition, denitrifying consortia which previously metabolized indole degraded oxindole with no lag period. Our data suggest that oxindole accumulation under methanogenic, but not under denitrifying conditions is caused by differences between relative rates of oxindole production and destruction. PMID:3345080

  6. A Pharmacogenetic Screening Experiment Demonstrating Principles of Genetic Constitution on Drug Metabolism.

    ERIC Educational Resources Information Center

    Robbins, Doris K.; Wedlund, Peter J.

    1990-01-01

    A laboratory experiment designed to provide rapid, inexpensive student exposure to pharmacogenetics in drug elimination and patient therapy is described. The test, performed on students, determines expression of a drug metabolism enzyme following ingestion of a probe drug. (Author/MSE)

  7. Predicting drug metabolism--an evaluation of the expert system METEOR.

    PubMed

    Testa, Bernard; Balmat, Anne-Loyse; Long, Anthony; Judson, Philip

    2005-07-01

    The paper begins with a discussion of the goals of metabolic predictions in early drug research, and some difficulties toward this objective, mainly the various substrate and product selectivities characteristic of drug metabolism. The major in silico approaches to predict drug metabolism are then classified and summarized. A discrimination is, thus, made between 'local' and 'global' systems. In its second part, an evaluation of METEOR, a rule-based expert system used to predict the metabolism of drugs and other xenobiotics, is reported. The published metabolic data of ten substrates were used in this evaluation, the overall results being discussed in terms of correct vs. disputable (i.e., false-positive and false-negative) predictions. The predictions for four representative substrates are presented in detail (Figs. 1-4), illustrating the interest of such an evaluation in identifying where and how predictive rules can be improved.

  8. How aneuploidy affects metabolic control and causes cancer.

    PubMed Central

    Rasnick, D; Duesberg, P H

    1999-01-01

    The complexity and diversity of cancer-specific phenotypes, including de-differentiation, invasiveness, metastasis, abnormal morphology and metabolism, genetic instability and progression to malignancy, have so far eluded explanation by a simple, coherent hypothesis. However, an adaptation of Metabolic Control Analysis supports the 100-year-old hypothesis that aneuploidy, an abnormal number of chromosomes, is the cause of cancer. The results demonstrate the currently counter-intuitive principle that it is the fraction of the genome undergoing differential expression, not the magnitude of the differential expression, that controls phenotypic transformation. Transforming the robust normal phenotype into cancer requires a twofold increase in the expression of thousands of normal gene products. The massive change in gene dose produces highly non-linear (i.e. qualitative) changes in the physiology and metabolism of cells and tissues. Since aneuploidy disrupts the natural balance of mitosis proteins, it also explains the notorious genetic instability of cancer cells as a consequence of the perpetual regrouping of chromosomes. In view of this and the existence of non-cancerous aneuploidy, we propose that cancer is the phenotype of cells above a certain threshold of aneuploidy. This threshold is reached either by the gradual, stepwise increase in the level of aneuploidy as a consequence of the autocatalysed genetic instability of aneuploid cells or by tetraploidization followed by a gradual loss of chromosomes. Thus the initiation step of carcinogenesis produces aneuploidy below the threshold for cancer, and the promotion step increases the level of aneuploidy above this threshold. We conclude that aneuploidy offers a simple and coherent explanation for all the cancer-specific phenotypes. Accordingly, the gross biochemical abnormalities, abnormal cellular size and morphology, the appearance of tumour-associated antigens, the high levels of secreted proteins responsible for

  9. Effects of Uremic Toxins on Transport and Metabolism of Different Biopharmaceutics Drug Disposition Classification System (BDDCS) Xenobiotics

    PubMed Central

    Reyes, Maribel; Benet, Leslie Z.

    2013-01-01

    Chronic kidney disease (CKD) is recognized to cause pharmacokinetic changes in renally excreted drugs; however, pharmacokinetic changes are also reported for drugs that are non-renally eliminated. Few studies have investigated how uremic toxins may affect drug transporters and metabolizing enzymes and how these may result in pharmacokinetic/metabolic changes in CKD. Here, we investigated the effects of uremic toxins and human uremic serum on the transport of the prototypical transporter substrate [3H]-estrone sulfate and three BDDCS drugs, propranolol, losartan, and eprosartan. We observed a significant decrease in [3H]-estrone sulfate, losartan, and eprosartan uptake with some uremic toxins in both transfected cells and rat hepatocytes. The uptake of losartan was decreased in rat and human hepatocytes (28%, and 48% respectively) in the presence of hemodialysis (HD) serum. Time-course studies of losartan showed a 27%, 65% and 68% increase in AUC in the presence of HD serum, rifampin, and sulfaphenazole respectively. Intracellular losartan AUC decreased significantly in the treatment groups and the metabolite AUC decreased by 41% and 26% in rifampin and sulfaphenazole treated group. The intracellular AUC of eprosartan increased 190% in the presence of HD serum. These studies indicate that the uremic toxins contained in HD serum play an important role in drug disposition through drug transporters, and that there would be differential effects depending on the BDDCS classification of the drug. PMID:21618544

  10. Drug Metabolism by the Host and Gut Microbiota: A Partnership or Rivalry?

    PubMed

    Swanson, Hollie I

    2015-10-01

    The importance of the gut microbiome in determining not only overall health, but also in the metabolism of drugs and xenobiotics, is rapidly emerging. It is becoming increasingly clear that the gut microbiota can act in concert with the host cells to maintain intestinal homeostasis, cometabolize drugs and xenobiotics, and alter the expression levels of drug-metabolizing enzymes and transporters and the expression and activity levels of nuclear receptors. In this myriad of activities, the impact of the microbiota may be beneficial or detrimental to the host. Given that the interplay between the gut microbiota and host cells is likely subject to high interindividual variability, this work has tremendous implications for our ability to predict accurately a particular drug's pharmacokinetics and a given patient population's response to drugs. In this issue of Drug Metabolism and Disposition, a series of articles is presented that illustrate the progress and challenges that lie ahead as we unravel the intricacies associated with drug and xenobiotic metabolism by the gut microbiota. These articles highlight the underlying mechanisms that are involved and the use of in vivo and in vitro approaches that are currently available for elucidating the role of the gut microbiota in drug and xenobiotic metabolism. These articles also shed light on exciting new avenues of research that may be pursued as we consider the role of the gut microbiota as an endocrine organ, a component of the brain-gut axis, and whether the gut microbiota is an appropriate and amenable target for new drugs. PMID:26261284

  11. Drug Metabolism by the Host and Gut Microbiota: A Partnership or Rivalry?

    PubMed

    Swanson, Hollie I

    2015-10-01

    The importance of the gut microbiome in determining not only overall health, but also in the metabolism of drugs and xenobiotics, is rapidly emerging. It is becoming increasingly clear that the gut microbiota can act in concert with the host cells to maintain intestinal homeostasis, cometabolize drugs and xenobiotics, and alter the expression levels of drug-metabolizing enzymes and transporters and the expression and activity levels of nuclear receptors. In this myriad of activities, the impact of the microbiota may be beneficial or detrimental to the host. Given that the interplay between the gut microbiota and host cells is likely subject to high interindividual variability, this work has tremendous implications for our ability to predict accurately a particular drug's pharmacokinetics and a given patient population's response to drugs. In this issue of Drug Metabolism and Disposition, a series of articles is presented that illustrate the progress and challenges that lie ahead as we unravel the intricacies associated with drug and xenobiotic metabolism by the gut microbiota. These articles highlight the underlying mechanisms that are involved and the use of in vivo and in vitro approaches that are currently available for elucidating the role of the gut microbiota in drug and xenobiotic metabolism. These articles also shed light on exciting new avenues of research that may be pursued as we consider the role of the gut microbiota as an endocrine organ, a component of the brain-gut axis, and whether the gut microbiota is an appropriate and amenable target for new drugs.

  12. An ex Vivo Model for Evaluating Blood-Brain Barrier Permeability, Efflux, and Drug Metabolism.

    PubMed

    Hellman, Karin; Aadal Nielsen, Peter; Ek, Fredrik; Olsson, Roger

    2016-05-18

    The metabolism of drugs in the brain is difficult to study in most species because of enzymatic instability in vitro and interference from peripheral metabolism in vivo. A locust ex vivo model that combines brain barrier penetration, efflux, metabolism, and analysis of the unbound fraction in intact brains was evaluated using known drugs. Clozapine was analyzed, and its major metabolites, clozapine N-oxide (CNO) and N-desmethylclozapine (NDMC), were identified and quantified. The back-transformation of CNO into clozapine observed in humans was also observed in locusts. In addition, risperidone, citalopram, fluoxetine, and haloperidol were studied, and one preselected metabolite for each drug was analyzed, identified, and quantified. Metabolite identification studies of clozapine and midazolam showed that the locust brain was highly metabolically active, and 18 and 14 metabolites, respectively, were identified. The unbound drug fraction of clozapine, NDMC, carbamazepine, and risperidone was analyzed. In addition, coadministration of drugs with verapamil or fluvoxamine was performed to evaluate drug-drug interactions in all setups. All findings correlated well with the data in the literature for mammals except for the stated fact that CNO is a highly blood-brain barrier permeant compound. Overall, the experiments indicated that invertebrates might be useful for screening of blood-brain barrier permeation, efflux, metabolism, and analysis of the unbound fraction of drugs in the brain in early drug discovery. PMID:26930271

  13. Artificial intelligence techniques for colorectal cancer drug metabolism: ontology and complex network.

    PubMed

    Martínez-Romero, Marcos; Vázquez-Naya, José M; Rabuñal, Juan R; Pita-Fernández, Salvador; Macenlle, Ramiro; Castro-Alvariño, Javier; López-Roses, Leopoldo; Ulla, José L; Martínez-Calvo, Antonio V; Vázquez, Santiago; Pereira, Javier; Porto-Pazos, Ana B; Dorado, Julián; Pazos, Alejandro; Munteanu, Cristian R

    2010-05-01

    Colorectal cancer is one of the most frequent types of cancer in the world and generates important social impact. The understanding of the specific metabolism of this disease and the transformations of the specific drugs will allow finding effective prevention, diagnosis and treatment of the colorectal cancer. All the terms that describe the drug metabolism contribute to the construction of ontology in order to help scientists to link the correlated information and to find the most useful data about this topic. The molecular components involved in this metabolism are included in complex network such as metabolic pathways in order to describe all the molecular interactions in the colorectal cancer. The graphical method of processing biological information such as graphs and complex networks leads to the numerical characterization of the colorectal cancer drug metabolic network by using invariant values named topological indices. Thus, this method can help scientists to study the most important elements in the metabolic pathways and the dynamics of the networks during mutations, denaturation or evolution for any type of disease. This review presents the last studies regarding ontology and complex networks of the colorectal cancer drug metabolism and a basic topology characterization of the drug metabolic process sub-ontology from the Gene Ontology.

  14. Abuse of Prescription (Rx) Drugs Affects Young Adults Most

    MedlinePlus

    ... Trends and Alerts Alcohol Club Drugs Cocaine Hallucinogens Heroin Inhalants Marijuana MDMA (Ecstasy/Molly) Methamphetamine Opioids Prescription ... died from overdoses of any other drug, including heroin and cocaine combined—and many more needed emergency ...

  15. Profiles in drug metabolism and toxicology: Richard Tecwyn Williams (1909-1979).

    PubMed

    Jones, Alan Wayne

    2015-01-01

    This article pays homage to the life and work of a veritable pioneer in toxicology and drug metabolism, namely a Welshman, Richard Tecwyn Williams, FRS. Professor Williams, or RT as he was known, made major contributions to knowledge about the metabolism and toxicology of drugs and xenobiotics during a scientific career spanning nearly 50 years. Author or coauthor of close to 400 research articles and reviews, including a classic book, entitled Detoxication Mechanisms, Williams and his research school investigated virtually all aspects of drug metabolism, especially conjugations. In particular, the concepts of phase 1 and phase II metabolic pathways were introduced by Williams; the biliary excretion of drugs was extensively studied as were species differences in drug metabolism and detoxication. Besides investigating the metabolism of many pharmaceutical drugs, such as sulfonamides and thalidomide, Williams and his group investigated the disposition and fate in the body of organic pesticides and recreational drugs of abuse, such as amphetamine, methamphetamine and lysergic acid diethylamide (LSD). PMID:26610047

  16. Ghrelin: a metabolic signal affecting the reproductive system.

    PubMed

    Lorenzi, Teresa; Meli, Rosaria; Marzioni, Daniela; Morroni, Manrico; Baragli, Alessandra; Castellucci, Mario; Gualillo, Oreste; Muccioli, Giampiero

    2009-04-01

    Ghrelin, an acylated 28 amino acid gastric peptide, was isolated from the stomach as an endogenous ligand for growth hormone (GH) secretagogue receptor in 1999. Circulating ghrelin is mainly produced by specific cells in the stomach's oxyntic glands. Ghrelin potently stimulates GH release and food intake and exhibits diverse effects, including ones on glucose metabolism and on secretion and motility of the gastrointestinal tract. Besides these effects on food intake and energy homeostasis, ghrelin is also involved in controlling reproductive functions, and a role for it as a novel regulator of the hypothalamic-pituitary gonadal axis is clearly emerging. We review recent ghrelin research with emphasis on its roles in the reproductive axis.

  17. Investigational cancer drugs targeting cell metabolism in clinical development

    PubMed Central

    Sborov, Douglas W; Haverkos, Bradley M; Harris, Pamela J

    2015-01-01

    Introduction Malignant cell transformation and tumor progression are associated with alterations in glycolysis, fatty acid synthesis, amino acid delivery and production of reactive oxygen species. With increased understanding of the role of metabolism in tumors, there has been interest in developing agents that target tumor specific metabolic pathways. Numerous promising agents targeting altered metabolic pathways are currently in Phase I – III clinical trials. Areas covered This paper reviews the early phase clinical trial development of these agents and provides perspective on the future direction of this emerging field. Specifically, the authors describe novel and repurposed therapies, focusing on the effects of each agent on tumor metabolism and results from relevant Phase I and II clinical trials. Expert opinion Metabolism modulating agents, alone and in combinations with other classes of agents, have shown efficacy in the treatment of neoplasm, which, the authors believe, will bear positive results in future studies. Because of the significant crosstalk between metabolic pathways and oncogenic signaling pathways, the authors also believe that combining metabolic modifiers with targeted agents will be an important strategy. An increased understanding of cancer metabolism, in addition to the continued study of metabolic modulators, should lead to further advances in this nascent therapeutic field in the future. PMID:25224845

  18. Metabolic differences in temperamental Brahman cattle can affect productivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many factors may adversely affect the growth and productivity of livestock. These include stressors associated with management practices, such as weaning, handling relative to transportation, and vaccination, that can modulate growth through the production of stress-related hormones (i.e., cortisol,...

  19. Reduction in hepatic drug metabolizing CYP3A4 activities caused by P450 oxidoreductase mutations identified in patients with disordered steroid metabolism

    SciTech Connect

    Flueck, Christa E.; Mullis, Primus E.; Pandey, Amit V.

    2010-10-08

    Research highlights: {yields} Cytochrome P450 3A4 (CYP3A4), metabolizes 50% of drugs in clinical use and requires NADPH-P450 reductase (POR). {yields} Mutations in human POR cause congenital adrenal hyperplasia from diminished activities of steroid metabolizing P450s. {yields} We are reporting that mutations in POR may reduce CYP3A4 activity. {yields} POR mutants Y181D, A457H, Y459H, V492E and R616X lost 99%, while A287P, C569Y and V608F lost 60-85% CYP3A4 activity. {yields} Reduction of CYP3A4 activity may cause increased risk of drug toxicities/adverse drug reactions in patients with POR mutations. -- Abstract: Cytochrome P450 3A4 (CYP3A4), the major P450 present in human liver metabolizes approximately half the drugs in clinical use and requires electrons supplied from NADPH through NADPH-P450 reductase (POR, CPR). Mutations in human POR cause a rare form of congenital adrenal hyperplasia from diminished activities of steroid metabolizing P450s. In this study we examined the effect of mutations in POR on CYP3A4 activity. We used purified preparations of wild type and mutant human POR and in vitro reconstitution with purified CYP3A4 to perform kinetic studies. We are reporting that mutations in POR identified in patients with disordered steroidogenesis/Antley-Bixler syndrome (ABS) may reduce CYP3A4 activity, potentially affecting drug metabolism in individuals carrying mutant POR alleles. POR mutants Y181D, A457H, Y459H, V492E and R616X had more than 99% loss of CYP3A4 activity, while POR mutations A287P, C569Y and V608F lost 60-85% activity. Loss of CYP3A4 activity may result in increased risk of drug toxicities and adverse drug reactions in patients with POR mutations.

  20. [Progress in quantitative methods based on liquid chromatography-mass spectrometry for drug metabolizing enzymes in human liver microsomes].

    PubMed

    Wang, Huanhuan; Lu, Yayao; Peng, Bo; Qian, Xiaohong; Zhang, Yangjun

    2015-06-01

    Cytochrome P450 (CYP) enzymes and uridine 5-diphospho-glucuronosyltransferase (UGT) enzymes are critical enzymes for drug metabolism. Both chemical drugs and traditional Chinese medicines are converted to more readily excreted compounds by drug metabolizing enzymes in human livers. Because of the disparate expression of CYP and UGT enzymes among different individuals, accurate quantification of these enzymes is essential for drug pharmacology, drug-drug interactions and drug clinical applications. The research progress in quantitative methods based on liquid chromatography-mass spectrometry for drug metabolizing enzymes in human liver microsomes in the recent decade is reviewed. PMID:26536756

  1. [Progress in quantitative methods based on liquid chromatography-mass spectrometry for drug metabolizing enzymes in human liver microsomes].

    PubMed

    Wang, Huanhuan; Lu, Yayao; Peng, Bo; Qian, Xiaohong; Zhang, Yangjun

    2015-06-01

    Cytochrome P450 (CYP) enzymes and uridine 5-diphospho-glucuronosyltransferase (UGT) enzymes are critical enzymes for drug metabolism. Both chemical drugs and traditional Chinese medicines are converted to more readily excreted compounds by drug metabolizing enzymes in human livers. Because of the disparate expression of CYP and UGT enzymes among different individuals, accurate quantification of these enzymes is essential for drug pharmacology, drug-drug interactions and drug clinical applications. The research progress in quantitative methods based on liquid chromatography-mass spectrometry for drug metabolizing enzymes in human liver microsomes in the recent decade is reviewed.

  2. Role of Protein–Protein Interactions in Cytochrome P450-Mediated Drug Metabolism and Toxicity

    PubMed Central

    2015-01-01

    Through their unique oxidative chemistry, cytochrome P450 monooxygenases (CYPs) catalyze the elimination of most drugs and toxins from the human body. Protein–protein interactions play a critical role in this process. Historically, the study of CYP–protein interactions has focused on their electron transfer partners and allosteric mediators, cytochrome P450 reductase and cytochrome b5. However, CYPs can bind other proteins that also affect CYP function. Some examples include the progesterone receptor membrane component 1, damage resistance protein 1, human and bovine serum albumin, and intestinal fatty acid binding protein, in addition to other CYP isoforms. Furthermore, disruption of these interactions can lead to altered paths of metabolism and the production of toxic metabolites. In this review, we summarize the available evidence for CYP protein–protein interactions from the literature and offer a discussion of the potential impact of future studies aimed at characterizing noncanonical protein–protein interactions with CYP enzymes. PMID:25133307

  3. Ozone treatment affects pigment precursor metabolism in pine seedlings.

    PubMed

    Shamay, Y.; Raskin, V. I.; Brandis, A. S.; Steinberger, H. E.; Marder, J. B.; Schwartz, A.

    2001-06-01

    Five-week-old seedlings of Pinus halepensis Mill. and Pinus brutia Ten. were exposed to air polluted with ozone (O3) (250 nl l-1, 12 h day-1 for 4 days) or to ambient air containing ca 10-20 nl l-1 O3, in the light (180 &mgr;mol m-2 s-1 photosynthetic photon flux density [PPFD], 12 h day-1) and then fed for 24 h in the light (100 &mgr;mol m-2 s-1 PPFD) with various radioactive precursors of chlorophyll (Chl) and carotene biosynthesis: 5-[4-14C]-aminolevulinic acid (14C-ALA), L-[14C(U)]-glutamic acid (14C-Glu), or D,L-[2-14C]-mevalonic acid (14C-MVA). Pigments were then extracted from cotyledons and fully expanded needles. Chl a and carotene were separated by thin-layer chromatography and high-performance liquid chromatography and their specific activities were determined. 14C-ALA and 14C-Glu labels were incorporated into Chl a and carotene. Exposure to O3 did not inhibit incorporation of 14C-ALA into Chl a molecules, but hydrolysis of Chl a showed that O3 inhibited phytol labelling of Chl a. Labelling of carotene was also inhibited by O3, but not when 14C-MVA was used as the label. These data suggest that O3 treatment inhibits (directly or indirectly) the biosynthesis of isoprenoids from products of ALA and Glu metabolism in the plastid, but not from MVA in the cytosol. This inhibition was more prominent when 14C-ALA was used as the label than when 14C-Glu was the labelling precursor. A significant increase in pheophorbide a, a tetrapyrrole component of Chl a labelling, and a concomitant decrease in phytol labelling was observed following incubation of O3-treated pine seedlings with 14C-ALA and 14C-Glu. Stronger inhibition of carotene biosynthesis and activation of Chl a tetrapyrrole labelling by 14C-ALA (in comparison with 14C-Glu) indicated that exposure to O3 inhibits the conversion of ALA to Glu as the first step in ALA catabolism. These results also suggested a more intensive Glu metabolism (in comparison with ALA) for carotene biosynthesis in the cytosol, as

  4. Ozone treatment affects pigment precursor metabolism in pine seedlings.

    PubMed

    Shamay, Y.; Raskin, V. I.; Brandis, A. S.; Steinberger, H. E.; Marder, J. B.; Schwartz, A.

    2001-06-01

    Five-week-old seedlings of Pinus halepensis Mill. and Pinus brutia Ten. were exposed to air polluted with ozone (O3) (250 nl l-1, 12 h day-1 for 4 days) or to ambient air containing ca 10-20 nl l-1 O3, in the light (180 &mgr;mol m-2 s-1 photosynthetic photon flux density [PPFD], 12 h day-1) and then fed for 24 h in the light (100 &mgr;mol m-2 s-1 PPFD) with various radioactive precursors of chlorophyll (Chl) and carotene biosynthesis: 5-[4-14C]-aminolevulinic acid (14C-ALA), L-[14C(U)]-glutamic acid (14C-Glu), or D,L-[2-14C]-mevalonic acid (14C-MVA). Pigments were then extracted from cotyledons and fully expanded needles. Chl a and carotene were separated by thin-layer chromatography and high-performance liquid chromatography and their specific activities were determined. 14C-ALA and 14C-Glu labels were incorporated into Chl a and carotene. Exposure to O3 did not inhibit incorporation of 14C-ALA into Chl a molecules, but hydrolysis of Chl a showed that O3 inhibited phytol labelling of Chl a. Labelling of carotene was also inhibited by O3, but not when 14C-MVA was used as the label. These data suggest that O3 treatment inhibits (directly or indirectly) the biosynthesis of isoprenoids from products of ALA and Glu metabolism in the plastid, but not from MVA in the cytosol. This inhibition was more prominent when 14C-ALA was used as the label than when 14C-Glu was the labelling precursor. A significant increase in pheophorbide a, a tetrapyrrole component of Chl a labelling, and a concomitant decrease in phytol labelling was observed following incubation of O3-treated pine seedlings with 14C-ALA and 14C-Glu. Stronger inhibition of carotene biosynthesis and activation of Chl a tetrapyrrole labelling by 14C-ALA (in comparison with 14C-Glu) indicated that exposure to O3 inhibits the conversion of ALA to Glu as the first step in ALA catabolism. These results also suggested a more intensive Glu metabolism (in comparison with ALA) for carotene biosynthesis in the cytosol, as

  5. Recent advances in endocrine metabolic immune disorders drug targeting: an editorial overview.

    PubMed

    Magrone, Thea; Jirillo, Emilio

    2015-01-01

    This editorial overview is aimed at reviewing all the work published by the Journal Endocrine Metabolic Immune Disorders-Drug Targets over the period 2012-2014. The main body of publications has been divided either into a section based on special issues and meeting proceedings or various specific sections according to different types of pathologies related to the field of endocrine metabolic immune disorder-drug targeting.

  6. Effect of honokiol on the induction of drug-metabolizing enzymes in human hepatocytes.

    PubMed

    Cho, Yong-Yeon; Jeong, Hyeon-Uk; Kim, Jeong-Han; Lee, Hye Suk

    2014-01-01

    Honokiol, 2-(4-hydroxy-3-prop-2-enyl-phenyl)-4-prop-2-enyl-phenol, an active component of Magnolia officinalis and Magnolia grandiflora, exerts various pharmacological activities such as antitumorigenic, antioxidative, anti-inflammatory, neurotrophic, and antithrombotic effects. To investigate whether honokiol acts as a perpetrator in drug interactions, messenger ribonucleic acid (mRNA) levels of phase I and II drug-metabolizing enzymes, including cytochrome P450 (CYP), UDP-glucuronosyltransferase (UGT), and sulfotransferase 2A1 (SULT2A1), were analyzed by real-time reverse transcription polymerase chain reaction following 48-hour honokiol exposure in three independent cryopreserved human hepatocyte cultures. Honokiol treatment at the highest concentration tested (50 μM) increased the CYP2B6 mRNA level and CYP2B6-catalyzed bupropion hydroxylase activity more than two-fold in three different hepatocyte cultures, indicating that honokiol induces CYP2B6 at higher concentrations. However, honokiol treatment (0.5-50 μM) did not significantly alter the mRNA levels of phase I enzymes (CYP1A2, CYP3A4, CYP2C8, CYP2C9, and CYP2C19) or phase II enzymes (UGT1A1, UGT1A4, UGT1A9, UGT2B7, and SULT2A1) in cryopreserved human hepatocyte cultures. CYP1A2-catalyzed phenacetin O-deethylase and CYP3A4-catalyzed midazolam 1'-hydroxylase activities were not affected by 48-hour honokiol treatment in cryopreserved human hepatocytes. These results indicate that honokiol is a weak CYP2B6 inducer and is unlikely to increase the metabolism of concomitant CYP2B6 substrates and cause pharmacokinetic-based drug interactions in humans.

  7. In vivo and in vitro inhibition of hepatic microsomal drug metabolism by ketoconazole.

    PubMed Central

    Mosca, P.; Bonazzi, P.; Novelli, G.; Jezequel, A. M.; Orlandi, F.

    1985-01-01

    Ketoconazole (KC), a broad spectrum antifungal drug, has been recognized recently as a cause of hepatic injury. The mechanism of the adverse reaction remains unclear: a metabolic idiosincrasy has been suggested. However as a substituted imidazole, KC might be expected to interfere with the hepatic microsomal mixed function oxidases. Ethylmorphine N-demethylase (E-DM) and aniline hydroxylase (A-OH) activities were determined in rat liver microsomes in the presence of increasing amounts of KC. Both were inhibited in an exponential fashion. The E-DM inhibition was almost complete at concentrations greater than 250 microM and was of the mixed type. A much weaker effect was observed for A-OH. A significant inhibition of E-DM was also observed when KC was administered in vivo to rats either orally for 7 days at the dose of 100 mg/kg/day (P less than 0.02) or intraperitoneally for 4 days at the dose of 50 or 100 mg/kg day (P less than 0.01 or P less than 0.001 respectively). A-OH activity was significantly reduced (P less than 0.01) only after ip administration of 100 mg/kg/day of the drug for 4 days. Neither the amount of cytochrome P-450 nor NADPH cytochrome c reductase activity were affected at the doses considered. These data show that KC interferes with hepatic oxidative drug metabolism and suggest that this mechanism might be involved in the unwanted side effects of therapy with KC. PMID:3936532

  8. Effect of honokiol on the induction of drug-metabolizing enzymes in human hepatocytes

    PubMed Central

    Cho, Yong-Yeon; Jeong, Hyeon-Uk; Kim, Jeong-Han; Lee, Hye Suk

    2014-01-01

    Honokiol, 2-(4-hydroxy-3-prop-2-enyl-phenyl)-4-prop-2-enyl-phenol, an active component of Magnolia officinalis and Magnolia grandiflora, exerts various pharmacological activities such as antitumorigenic, antioxidative, anti-inflammatory, neurotrophic, and antithrombotic effects. To investigate whether honokiol acts as a perpetrator in drug interactions, messenger ribonucleic acid (mRNA) levels of phase I and II drug-metabolizing enzymes, including cytochrome P450 (CYP), UDP-glucuronosyltransferase (UGT), and sulfotransferase 2A1 (SULT2A1), were analyzed by real-time reverse transcription polymerase chain reaction following 48-hour honokiol exposure in three independent cryopreserved human hepatocyte cultures. Honokiol treatment at the highest concentration tested (50 μM) increased the CYP2B6 mRNA level and CYP2B6-catalyzed bupropion hydroxylase activity more than two-fold in three different hepatocyte cultures, indicating that honokiol induces CYP2B6 at higher concentrations. However, honokiol treatment (0.5–50 μM) did not significantly alter the mRNA levels of phase I enzymes (CYP1A2, CYP3A4, CYP2C8, CYP2C9, and CYP2C19) or phase II enzymes (UGT1A1, UGT1A4, UGT1A9, UGT2B7, and SULT2A1) in cryopreserved human hepatocyte cultures. CYP1A2-catalyzed phenacetin O-deethylase and CYP3A4-catalyzed midazolam 1′-hydroxylase activities were not affected by 48-hour honokiol treatment in cryopreserved human hepatocytes. These results indicate that honokiol is a weak CYP2B6 inducer and is unlikely to increase the metabolism of concomitant CYP2B6 substrates and cause pharmacokinetic-based drug interactions in humans. PMID:25395831

  9. Effect of honokiol on the induction of drug-metabolizing enzymes in human hepatocytes.

    PubMed

    Cho, Yong-Yeon; Jeong, Hyeon-Uk; Kim, Jeong-Han; Lee, Hye Suk

    2014-01-01

    Honokiol, 2-(4-hydroxy-3-prop-2-enyl-phenyl)-4-prop-2-enyl-phenol, an active component of Magnolia officinalis and Magnolia grandiflora, exerts various pharmacological activities such as antitumorigenic, antioxidative, anti-inflammatory, neurotrophic, and antithrombotic effects. To investigate whether honokiol acts as a perpetrator in drug interactions, messenger ribonucleic acid (mRNA) levels of phase I and II drug-metabolizing enzymes, including cytochrome P450 (CYP), UDP-glucuronosyltransferase (UGT), and sulfotransferase 2A1 (SULT2A1), were analyzed by real-time reverse transcription polymerase chain reaction following 48-hour honokiol exposure in three independent cryopreserved human hepatocyte cultures. Honokiol treatment at the highest concentration tested (50 μM) increased the CYP2B6 mRNA level and CYP2B6-catalyzed bupropion hydroxylase activity more than two-fold in three different hepatocyte cultures, indicating that honokiol induces CYP2B6 at higher concentrations. However, honokiol treatment (0.5-50 μM) did not significantly alter the mRNA levels of phase I enzymes (CYP1A2, CYP3A4, CYP2C8, CYP2C9, and CYP2C19) or phase II enzymes (UGT1A1, UGT1A4, UGT1A9, UGT2B7, and SULT2A1) in cryopreserved human hepatocyte cultures. CYP1A2-catalyzed phenacetin O-deethylase and CYP3A4-catalyzed midazolam 1'-hydroxylase activities were not affected by 48-hour honokiol treatment in cryopreserved human hepatocytes. These results indicate that honokiol is a weak CYP2B6 inducer and is unlikely to increase the metabolism of concomitant CYP2B6 substrates and cause pharmacokinetic-based drug interactions in humans. PMID:25395831

  10. LC-MS-based metabolomics in drug metabolism.

    PubMed

    Chen, Chi; Gonzalez, Frank J; Idle, Jeffrey R

    2007-01-01

    Xenobiotic metabolism, a ubiquitous natural response to foreign compounds, elicits initiating signals for many pathophysiological events. Currently, most widely used techniques for identifying xenobiotic metabolites and metabolic pathways are empirical and largely based on in vitro incubation assays and in vivo radiotracing experiments. Recent work in our lab has shown that LC-MS-based metabolomic techniques are useful tools for xenobiotic metabolism research since multivariate data analysis in metabolomics can significantly rationalize the processes of xenobiotic metabolite identification and metabolic pathway analysis. In this review, the technological elements of LC-MS-based metabolomics for constructing high-quality datasets and conducting comprehensive data analysis are examined. Four novel approaches of using LC-MS-based metabolomic techniques in xenobiotic metabolism research are proposed and illustrated by case studies and proof-of-concept experiments, and the perspective on their application is further discussed.

  11. [How strongly does heavy work in the heat affect metabolism?].

    PubMed

    Zöller, H; May, B; Weiss, M; Gross, W

    1981-06-19

    The study covered 39 acclimatised workers of a ball-bearing forge, aged 39,03 +/- 9,95 years. Temperature of the air, relative humidity and air speed were measured immediately at work. Additionally electrocardiogram, heart rate and temperature of the skin were continuously transmitted by telemetry. Before and at the end of the shift analysis of blood pressure, heart rate, electrocardiogram, blood cells and coagulation, serum acidity and a great number of other metabolic parameters was performed. The netto calories were calculated as 3250 kcal/8 hours (= 13585 kJ/8 hours). Hematological analysis demonstrated a tendency to increase of leucocytes favouring neutrophil granulocytes. The main alterations comprised decrease of actual pH, base excess and standard bicarbonate. Furthermore serum lactate and triglycerides increased, creatinine attained the upper limit of the normal range, mineralogram remained unchanged by drinking ad libitum. The so called "liver enzymes" remained stable. As to circulatory parameters systolic blood pressure slightly declined whilst heart rate increased.

  12. Carbon-carbon bond cleavage and formation reactions in drug metabolism and the role of metabolic enzymes.

    PubMed

    Bolleddula, Jayaprakasam; Chowdhury, Swapan K

    2015-01-01

    Elimination of xenobiotics from the human body is often facilitated by a transformation to highly water soluble and more ionizable molecules. In general, oxidation-reduction, hydrolysis, and conjugation reactions are common biotransformation reactions that are catalyzed by various metabolic enzymes including cytochrome P450s (CYPs), non-CYPs, and conjugative enzymes. Although carbon-carbon (C-C) bond formation and cleavage reactions are known to exist in plant secondary metabolism, these reactions are relatively rare in mammalian metabolism and are considered exceptions. However, various reactions such as demethylation, dealkylation, dearylation, reduction of alkyl chain, ring expansion, ring contraction, oxidative elimination of a nitrile through C-C bond cleavage, and dimerization, and glucuronidation through C-C bond formation have been reported for drug molecules. Carbon-carbon bond cleavage reactions for drug molecules are primarily catalyzed by CYP enzymes, dimerization is mediated by peroxidases, and C-glucuronidation is catalyzed by UGT1A9. This review provides an overview of C-C bond cleavage and formation reactions in drug metabolism and the metabolic enzymes associated with these reactions.

  13. Aspergillus nidulans galactofuranose biosynthesis affects antifungal drug sensitivity.

    PubMed

    Alam, Md Kausar; El-Ganiny, Amira M; Afroz, Sharmin; Sanders, David A R; Liu, Juxin; Kaminskyj, Susan G W

    2012-12-01

    The cell wall is essential for fungal survival in natural environments. Many fungal wall carbohydrates are absent from humans, so they are a promising source of antifungal drug targets. Galactofuranose (Galf) is a sugar that decorates certain carbohydrates and lipids. It comprises about 5% of the Aspergillus fumigatus cell wall, and may play a role in systemic aspergillosis. We are studying Aspergillus wall formation in the tractable model system, A. nidulans. Previously we showed single-gene deletions of three sequential A. nidulans Galf biosynthesis proteins each caused similar hyphal morphogenesis defects and 500-fold reduced colony growth and sporulation. Here, we generated ugeA, ugmA and ugtA strains controlled by the alcA(p) or niiA(p) regulatable promoters. For repression and expression, alcA(p)-regulated strains were grown on complete medium with glucose or threonine, whereas niiA(p)-regulated strains were grown on minimal medium with ammonium or nitrate. Expression was assessed by qPCR and colony phenotype. The alcA(p) and niiA(p) strains produced similar effects: colonies resembling wild type for gene expression, and resembling deletion strains for gene repression. Galf immunolocalization using the L10 monoclonal antibody showed that ugmA deletion and repression phenotypes correlated with loss of hyphal wall Galf. None of the gene manipulations affected itraconazole sensitivity, as expected. Deletion of any of ugmA, ugeA, ugtA, their repression by alcA(p) or niiA(p), OR, ugmA overexpression by alcA(p), increased sensitivity to Caspofungin. Strains with alcA(p)-mediated overexpression of ugeA and ugtA had lower caspofungin sensitivity. Galf appears to play an important role in A. nidulans growth and vigor.

  14. Maternal age affects brain metabolism in adult children of mothers affected by Alzheimer’s disease

    PubMed Central

    Mosconi, Lisa; Tsui, Wai; Murray, John; McHugh, Pauline; Li, Yi; Williams, Schantel; Pirraglia, Elizabeth; Glodzik, Lidia; De Santi, Susan; Vallabhajosula, Shankar; de Leon, Mony J.

    2011-01-01

    Cognitively normal (NL) individuals with a maternal history of late-onset Alzheimer’s disease (MH) show reduced brain glucose metabolism on FDG-PET as compared to those with a paternal history (PH) and those with negative family history (NH) of Alzheimer’s disease (AD). This FDG-PET study investigates whether metabolic deficits in NL MH are associated with advancing maternal age at birth. Ninety-six NL individuals with FDG-PET were examined, including 36 MH, 24 PH, and 36 NH. Regional-to-whole brain gray matter standardized FDG uptake value ratios were examined for associations with parental age across groups using automated regions-of-interest and statistical parametric mapping. Groups were comparable for clinical and neuropsychological measures. Brain metabolism in AD-vulnerable regions was lower in MH compared to NH and PH, and negatively correlated with maternal age at birth only in MH. There were no associations between paternal age and metabolism in any group. Evidence for a maternally inherited, maternal age-related mechanism provides further insight on risk factors and genetic transmission in late-onset AD. PMID:21514691

  15. Maternal age affects brain metabolism in adult children of mothers affected by Alzheimer's disease.

    PubMed

    Mosconi, Lisa; Tsui, Wai; Murray, John; McHugh, Pauline; Li, Yi; Williams, Schantel; Pirraglia, Elizabeth; Glodzik, Lidia; De Santi, Susan; Vallabhajosula, Shankar; de Leon, Mony J

    2012-03-01

    Cognitively normal (NL) individuals with a maternal history of late-onset Alzheimer's disease (MH) show reduced brain glucose metabolism on FDG-PET as compared to those with a paternal history (PH) and those with negative family history (NH) of Alzheimer's disease (AD). This FDG-PET study investigates whether metabolic deficits in NL MH are associated with advancing maternal age at birth. Ninety-six NL individuals with FDG-PET were examined, including 36 MH, 24 PH, and 36 NH. Regional-to-whole brain gray matter standardized FDG uptake value ratios were examined for associations with parental age across groups using automated regions-of-interest and statistical parametric mapping. Groups were comparable for clinical and neuropsychological measures. Brain metabolism in AD-vulnerable regions was lower in MH compared to NH and PH, and negatively correlated with maternal age at birth only in MH. There were no associations between paternal age and metabolism in any group. Evidence for a maternally inherited, maternal age-related mechanism provides further insight on risk factors and genetic transmission in late-onset AD.

  16. Childhood obesity affects adult metabolic syndrome and diabetes.

    PubMed

    Liang, Yajun; Hou, Dongqing; Zhao, Xiaoyuan; Wang, Liang; Hu, Yuehua; Liu, Junting; Cheng, Hong; Yang, Ping; Shan, Xinying; Yan, Yinkun; Cruickshank, J Kennedy; Mi, Jie

    2015-09-01

    We seek to observe the association between childhood obesity by different measures and adult obesity, metabolic syndrome (MetS), and diabetes. Thousand two hundred and nine subjects from "Beijing Blood Pressure Cohort Study" were followed 22.9 ± 0.5 years in average from childhood to adulthood. We defined childhood obesity using body mass index (BMI) or left subscapular skinfold (LSSF), and adult obesity as BMI ≥ 28 kg/m(2). MetS was defined according to the joint statement of International Diabetes Federation and American Heart Association with modified waist circumference (≥ 90/85 cm for men/women). Diabetes was defined as fasting plasma glucose ≥ 7.0 mmol/L or blood glucose 2 h after oral glucose tolerance test ≥ 11.1 mmol/L or currently using blood glucose-lowering agents. Multiple linear and logistic regression models were used to assess the association. The incidence of adult obesity was 13.4, 60.0, 48.3, and 65.1 % for children without obesity, having obesity by BMI only, by LSSF only, and by both, respectively. Compared to children without obesity, children obese by LSSF only or by both had higher risk of diabetes. After controlling for adult obesity, childhood obesity predicted independently long-term risks of diabetes (odds ratio 2.8, 95 % confidence interval 1.2-6.3) or abdominal obesity (2.7, 1.6-4.7) other than MetS as a whole (1.2, 0.6-2.4). Childhood obesity predicts long-term risk of adult diabetes, and the effect is independent of adult obesity. LSSF is better than BMI in predicting adult diabetes.

  17. Spastin binds to lipid droplets and affects lipid metabolism.

    PubMed

    Papadopoulos, Chrisovalantis; Orso, Genny; Mancuso, Giuseppe; Herholz, Marija; Gumeni, Sentiljana; Tadepalle, Nimesha; Jüngst, Christian; Tzschichholz, Anne; Schauss, Astrid; Höning, Stefan; Trifunovic, Aleksandra; Daga, Andrea; Rugarli, Elena I

    2015-04-01

    Mutations in SPAST, encoding spastin, are the most common cause of autosomal dominant hereditary spastic paraplegia (HSP). HSP is characterized by weakness and spasticity of the lower limbs, owing to progressive retrograde degeneration of the long corticospinal axons. Spastin is a conserved microtubule (MT)-severing protein, involved in processes requiring rearrangement of the cytoskeleton in concert to membrane remodeling, such as neurite branching, axonal growth, midbody abscission, and endosome tubulation. Two isoforms of spastin are synthesized from alternative initiation codons (M1 and M87). We now show that spastin-M1 can sort from the endoplasmic reticulum (ER) to pre- and mature lipid droplets (LDs). A hydrophobic motif comprised of amino acids 57 through 86 of spastin was sufficient to direct a reporter protein to LDs, while mutation of arginine 65 to glycine abolished LD targeting. Increased levels of spastin-M1 expression reduced the number but increased the size of LDs. Expression of a mutant unable to bind and sever MTs caused clustering of LDs. Consistent with these findings, ubiquitous overexpression of Dspastin in Drosophila led to bigger and less numerous LDs in the fat bodies and increased triacylglycerol levels. In contrast, Dspastin overexpression increased LD number when expressed specifically in skeletal muscles or nerves. Downregulation of Dspastin and expression of a dominant-negative variant decreased LD number in Drosophila nerves, skeletal muscle and fat bodies, and reduced triacylglycerol levels in the larvae. Moreover, we found reduced amount of fat stores in intestinal cells of worms in which the spas-1 homologue was either depleted by RNA interference or deleted. Taken together, our data uncovers an evolutionarily conserved role of spastin as a positive regulator of LD metabolism and open up the possibility that dysfunction of LDs in axons may contribute to the pathogenesis of HSP.

  18. Human hepatoma cell lines on gas foaming templated alginate scaffolds for in vitro drug-drug interaction and metabolism studies.

    PubMed

    Stampella, A; Rizzitelli, G; Donati, F; Mazzarino, M; de la Torre, X; Botrè, F; Giardi, M F; Dentini, M; Barbetta, A; Massimi, M

    2015-12-25

    Liver in vitro systems that allow reliable prediction of major human in vivo metabolic pathways have a significant impact in drug screening and drug metabolism research. In the present study, a novel porous scaffold composed of alginate was prepared by employing a gas-in-liquid foaming approach. Galactose residues were introduced on scaffold surfaces to promote cell adhesion and to enhance liver specific functions of the entrapped HepG2/C3A cells. Hepatoma cells in the gal-alginate scaffold showed higher levels of liver specific products (albumin and urea) and were more responsive to specific inducers (e.g. dexamethasone) and inhibitors (e.g. ketoconazole) of the CYP3A4 system than in conventional monolayer culture. HepG2/C3A cells were also more efficient in terms of rapid elimination of testosterone, used as a model substance, at rates comparable to those of in vivo excretion. In addition, an improvement in metabolism of testosterone, in terms of phase II metabolite formation, was also observed when the more differentiated HepaRG cells were used. Together the data suggest that hepatocyte/gas templated alginate-systems provide an innovative high throughput platform for in vitro drug metabolism and drug-drug interaction studies, with broad fields of application, and might provide a valid tool for minimizing animal use in preclinical testing of human relevance.

  19. Structural, Metabolic, and Functional Brain Abnormalities as a Result of Prenatal Exposure to Drugs of Abuse: Evidence from Neuroimaging

    PubMed Central

    Roussotte, Florence; Soderberg, Lindsay

    2010-01-01

    Prenatal exposure to alcohol and stimulants negatively affects the developing trajectory of the central nervous system in many ways. Recent advances in neuroimaging methods have allowed researchers to study the structural, metabolic, and functional abnormalities resulting from prenatal exposure to drugs of abuse in living human subjects. Here we review the neuroimaging literature of prenatal exposure to alcohol, cocaine, and methamphetamine. Neuroimaging studies of prenatal alcohol exposure have reported differences in the structure and metabolism of many brain systems, including in frontal, parietal, and temporal regions, in the cerebellum and basal ganglia, as well as in the white matter tracts that connect these brain regions. Functional imaging studies have identified significant differences in brain activation related to various cognitive domains as a result of prenatal alcohol exposure. The published literature of prenatal exposure to cocaine and methamphetamine is much smaller, but evidence is beginning to emerge suggesting that exposure to stimulant drugs in utero may be particularly toxic to dopamine-rich basal ganglia regions. Although the interpretation of such findings is somewhat limited by the problem of polysubstance abuse and by the difficulty of obtaining precise exposure histories in retrospective studies, such investigations provide important insights into the effects of drugs of abuse on the structure, function, and metabolism of the developing human brain. These insights may ultimately help clinicians develop better diagnostic tools and devise appropriate therapeutic interventions to improve the condition of children with prenatal exposure to drugs of abuse. PMID:20978945

  20. Guide to Children Affected by Parental Drug Abuse

    ERIC Educational Resources Information Center

    Davies, Leah

    2010-01-01

    A conservative estimate is that one in six children in school today has a parent dependent on or addicted to alcohol or other drugs. This places these students at high risk for social and emotional problems, as well as for school failure, drug use, and delinquency. Schools, however, are a logical place to reach them. Identifying children of those…

  1. Lactobacillus acidophilus NCFM affects vitamin E acetate metabolism and intestinal bile acid signature in monocolonized mice

    PubMed Central

    Roager, Henrik M; Sulek, Karolina; Skov, Kasper; Frandsen, Henrik L; Smedsgaard, Jørn; Wilcks, Andrea; Skov, Thomas H; Villas-Boas, Silas G; Licht, Tine R

    2014-01-01

    Monocolonization of germ-free (GF) mice enables the study of specific bacterial species in vivo. Lactobacillus acidophilus NCFMTM (NCFM) is a probiotic strain; however, many of the mechanisms behind its health-promoting effect remain unknown. Here, we studied the effects of NCFM on the metabolome of jejunum, cecum, and colon of NCFM monocolonized (MC) and GF mice using liquid chromatography coupled to mass-spectrometry (LC-MS). The study adds to existing evidence that NCFM in vivo affects the bile acid signature of mice, in particular by deconjugation. Furthermore, we confirmed that carbohydrate metabolism is affected by NCFM in the mouse intestine as especially the digestion of oligosaccharides (penta- and tetrasaccharides) was increased in MC mice. Additionally, levels of α-tocopherol acetate (vitamin E acetate) were higher in the intestine of GF mice than in MC mice, suggesting that NCFM affects the vitamin E acetate metabolism. NCFM did not digest vitamin E acetate in vitro, suggesting that direct bacterial metabolism was not the cause of the altered metabolome in vivo. Taken together, our results suggest that NCFM affects intestinal carbohydrate metabolism, bile acid metabolism and vitamin E metabolism, although it remains to be investigated whether this effect is unique to NCFM. PMID:24717228

  2. Recent Advances in Targeting Tumor Energy Metabolism with Tumor Acidosis as a Biomarker of Drug Efficacy

    PubMed Central

    Akhenblit, Paul J; Pagel, Mark D

    2016-01-01

    Cancer cells employ a deregulated cellular metabolism to leverage survival and growth advantages. The unique tumor energy metabolism presents itself as a promising target for chemotherapy. A pool of tumor energy metabolism targeting agents has been developed after several decades of efforts. This review will cover glucose and fatty acid metabolism, PI3K/AKT/mTOR, HIF-1 and glutamine pathways in tumor energy metabolism, and how they are being exploited for treatments and therapies by promising pre-clinical or clinical drugs being developed or investigated. Additionally, acidification of the tumor extracellular microenvironment is hypothesized to be the result of active tumor metabolism. This implies that tumor extracellular pH (pHe) can be a biomarker for assessing the efficacy of therapies that target tumor metabolism. Several translational molecular imaging methods (PET, MRI) for interrogating tumor acidification and its suppression are discussed as well. PMID:26962408

  3. QSAR and QM/MM approaches applied to drug metabolism prediction.

    PubMed

    Braga, R C; Andrade, C H

    2012-06-01

    In modern drug discovery process, ADME/Tox properties should be determined as early as possible in the test cascade to allow a timely assessment of their property profiles. To help medicinal chemists in designing new compounds with improved pharmacokinetics, the knowledge of the soft spot position or the site of metabolism (SOM) is needed. In recent years, large number of in silico approaches for metabolism prediction have been developed and reported. Among these methods, QSAR models and combined quantum mechanics/molecular mechanics (QM/MM) methods for predicting drug metabolism have undergone significant advances. This review provides a perspective of the utility of QSAR and QM/MM approaches on drug metabolism prediction, highlighting the present challenges, limitations, and future perspectives in medicinal chemistry.

  4. Preclinical drug metabolism in the age of high-throughput screening: an industrial perspective.

    PubMed

    Rodrigues, A D

    1997-11-01

    With the advent of genomics, combinatorial paradigms and high-throughput screen (HTS)-based pharmacological testing, the number of compounds flowing through the discovery pipeline is likely to escalate. At the same time, with increased knowledge of the human drug-metabolizing enzymes and the availability of in vitro absorption-metabolism (AM) models, Preclinical Drug Metabolism is poised to meet the challenges of HTS. In order to be successful, however, a rational HTS strategy (vs. serendipitous HTS) has to be employed. Such a strategy is based on automation, validation and integration of in vitro AM models and database management (AVID). A generalized strategy for rational (AVID-based) HTS in Preclinical Drug Metabolism is described briefly.

  5. Minimally Invasive Swine Experimental Model for the In Vivo Study of Liver Metabolism of Drugs

    PubMed Central

    Piazza, O; Romano, R; Scarpati, G; Esposito, C; Cavaglià, E; Corona, M

    2012-01-01

    Purpose To develop a clinically relevant porcine model for the study of hepatic metabolism of drugs by means of hepatic vein catheterization. Materials and Methods: review of literature and elaboration of a hypothesis, design of an experimental method. Results: recent clinical studies were conducted by withdrawing cirrhotic patients’ blood from right hepatic vein during hepatic vein pressure gradient measurements. Basing on our personal clinical experience and evaluation of research needs, an experimental model is proposed. Conclusions: contemporary measurement of peripheral and hepatic concentration of drugs by peripheral vein and hepatic vein catheterization can be used to create a reliable and reproducible porcine model to study liver metabolism of drugs in vivo. PMID:23905064

  6. Dietary carbohydrate restriction induces a unique metabolic state positively affecting atherogenic dyslipidemia, fatty acid partitioning, and metabolic syndrome.

    PubMed

    Volek, Jeff S; Fernandez, Maria Luz; Feinman, Richard D; Phinney, Stephen D

    2008-09-01

    Abnormal fatty acid metabolism and dyslipidemia play an intimate role in the pathogenesis of metabolic syndrome and cardiovascular diseases. The availability of glucose and insulin predominate as upstream regulatory elements that operate through a collection of transcription factors to partition lipids toward anabolic pathways. The unraveling of the details of these cellular events has proceeded rapidly, but their physiologic relevance to lifestyle modification has been largely ignored. Here we highlight the role of dietary input, specifically carbohydrate intake, in the mechanism of metabolic regulation germane to metabolic syndrome. The key principle is that carbohydrate, directly or indirectly through the effect of insulin, controls the disposition of excess dietary nutrients. Dietary carbohydrate modulates lipolysis, lipoprotein assembly and processing and affects the relation between dietary intake of saturated fat intake and circulating levels. Several of these processes are the subject of intense investigation at the cellular level. We see the need to integrate these cellular mechanisms with results from low-carbohydrate diet trials that have shown reduced cardiovascular risk through improvement in hepatic, intravascular, and peripheral processing of lipoproteins, alterations in fatty acid composition, and reductions in other cardiovascular risk factors, notably inflammation. From the current state of the literature, however, low-carbohydrate diets are grounded in basic metabolic principles and the data suggest that some form of carbohydrate restriction is a candidate to be the preferred dietary strategy for cardiovascular health beyond weight regulation.

  7. Bimodal targeting of microsomal cytochrome P450s to mitochondria: implications in drug metabolism and toxicity

    PubMed Central

    Sangar, Michelle C; Bansal, Seema

    2010-01-01

    Importance of the field Microsomal cytochrome P450s are critical for drug metabolism and toxicity. Recent studies show that these CYPs are also present in the mitochondrial compartment of human and rodent tissues. Mitochondrial CYP1A1 and 2E1 show both overlapping and distinct metabolic activities compared to microsomal forms. Mitochondrial CYP2E1 also induces oxidative stress. The mechanisms of mitochondria targeting of CYPs and their role in drug metabolism and toxicity are important factors to consider while determining the drug dose and in drug development. Areas covered in this review This review highlights the mechanisms of bimodal targeting of CYP1A1, 2B1, 2E1 and 2D6 to mitochondria and microsomes. The review also discusses differences in structure and function of mitochondrial CYPs. What the readers will gain A comprehensive review of the literature on drug metabolism in the mitochondrial compartment, and their potential for inducing mitochondrial dysfunction. Take home message Studies on the biochemistry, pharmacology and pharmacogenetic analysis of CYPs are mostly focused on the molecular forms associated with the microsomal membrane. However, the mitochondrial CYPs in some individuals can represent a substantial part of the tissue pool and contribute in a significant way to drug metabolism, clearance and toxicity. PMID:20629582

  8. Metabolomics and systems pharmacology: why and how to model the human metabolic network for drug discovery☆

    PubMed Central

    Kell, Douglas B.; Goodacre, Royston

    2014-01-01

    Metabolism represents the ‘sharp end’ of systems biology, because changes in metabolite concentrations are necessarily amplified relative to changes in the transcriptome, proteome and enzyme activities, which can be modulated by drugs. To understand such behaviour, we therefore need (and increasingly have) reliable consensus (community) models of the human metabolic network that include the important transporters. Small molecule ‘drug’ transporters are in fact metabolite transporters, because drugs bear structural similarities to metabolites known from the network reconstructions and from measurements of the metabolome. Recon2 represents the present state-of-the-art human metabolic network reconstruction; it can predict inter alia: (i) the effects of inborn errors of metabolism; (ii) which metabolites are exometabolites, and (iii) how metabolism varies between tissues and cellular compartments. However, even these qualitative network models are not yet complete. As our understanding improves so do we recognise more clearly the need for a systems (poly)pharmacology. PMID:23892182

  9. Systematic Identification of Anti-Fungal Drug Targets by a Metabolic Network Approach

    PubMed Central

    Kaltdorf, Martin; Srivastava, Mugdha; Gupta, Shishir K.; Liang, Chunguang; Binder, Jasmin; Dietl, Anna-Maria; Meir, Zohar; Haas, Hubertus; Osherov, Nir; Krappmann, Sven; Dandekar, Thomas

    2016-01-01

    New antimycotic drugs are challenging to find, as potential target proteins may have close human orthologs. We here focus on identifying metabolic targets that are critical for fungal growth and have minimal similarity to targets among human proteins. We compare and combine here: (I) direct metabolic network modeling using elementary mode analysis and flux estimates approximations using expression data, (II) targeting metabolic genes by transcriptome analysis of condition-specific highly expressed enzymes, and (III) analysis of enzyme structure, enzyme interconnectedness (“hubs”), and identification of pathogen-specific enzymes using orthology relations. We have identified 64 targets including metabolic enzymes involved in vitamin synthesis, lipid, and amino acid biosynthesis including 18 targets validated from the literature, two validated and five currently examined in own genetic experiments, and 38 further promising novel target proteins which are non-orthologous to human proteins, involved in metabolism and are highly ranked drug targets from these pipelines. PMID:27379244

  10. Role of Cytochrome P450 2C8 in Drug Metabolism and Interactions.

    PubMed

    Backman, Janne T; Filppula, Anne M; Niemi, Mikko; Neuvonen, Pertti J

    2016-01-01

    During the last 10-15 years, cytochrome P450 (CYP) 2C8 has emerged as an important drug-metabolizing enzyme. CYP2C8 is highly expressed in human liver and is known to metabolize more than 100 drugs. CYP2C8 substrate drugs include amodiaquine, cerivastatin, dasabuvir, enzalutamide, imatinib, loperamide, montelukast, paclitaxel, pioglitazone, repaglinide, and rosiglitazone, and the number is increasing. Similarly, many drugs have been identified as CYP2C8 inhibitors or inducers. In vivo, already a small dose of gemfibrozil, i.e., 10% of its therapeutic dose, is a strong, irreversible inhibitor of CYP2C8. Interestingly, recent findings indicate that the acyl-β-glucuronides of gemfibrozil and clopidogrel cause metabolism-dependent inactivation of CYP2C8, leading to a strong potential for drug interactions. Also several other glucuronide metabolites interact with CYP2C8 as substrates or inhibitors, suggesting that an interplay between CYP2C8 and glucuronides is common. Lack of fully selective and safe probe substrates, inhibitors, and inducers challenges execution and interpretation of drug-drug interaction studies in humans. Apart from drug-drug interactions, some CYP2C8 genetic variants are associated with altered CYP2C8 activity and exhibit significant interethnic frequency differences. Herein, we review the current knowledge on substrates, inhibitors, inducers, and pharmacogenetics of CYP2C8, as well as its role in clinically relevant drug interactions. In addition, implications for selection of CYP2C8 marker and perpetrator drugs to investigate CYP2C8-mediated drug metabolism and interactions in preclinical and clinical studies are discussed. PMID:26721703

  11. Factors affecting the reversal of antimicrobial-drug resistance.

    PubMed

    Johnsen, Pål J; Townsend, Jeffrey P; Bøhn, Thomas; Simonsen, Gunnar S; Sundsfjord, Arnfinn; Nielsen, Kaare M

    2009-06-01

    The persistence or loss of acquired antimicrobial-drug resistance in bacterial populations previously exposed to drug-selective pressure depends on several biological processes. We review mechanisms promoting or preventing the loss of resistance, including rates of reacquisition, effects of resistance traits on bacterial fitness, linked selection, and segregational stability of resistance determinants. As a case study, we discuss the persistence of glycopeptide-resistant enterococci in Norwegian and Danish poultry farms 12 years after the ban of the animal growth promoter avoparcin. We conclude that complete eradication of antimicrobial resistance in bacterial populations following relaxed drug-selective pressures is not straightforward. Resistance determinants may persist at low, but detectable, levels for many years in the absence of the corresponding drugs. PMID:19467475

  12. FACTORS AFFECTING THE DEPOSITION OF INHALED POROUS DRUG PARTICLES

    EPA Science Inventory

    Abstract
    Recent findings indicate that the inhalation of large manufactured porous particles may be particularly effective for drug delivery. In this study, a mathematical model was employed to systematically investigate the effects of particle size, particle density, aerosol ...

  13. Drug Metabolizing Enzymes in Type II Diabetes and their Pharmacogenetics During Therapy of Anti-Diabetes Drugs.

    PubMed

    Chakraborty, Chiranjib; Hsu, Minna J; Agoramoorthy, Govindasamy

    2015-01-01

    The type 2 diabetes or T2D mellitus has turn into an epidemic throughout the globe in recent years. Various forms of treatment modalities have been available for patients with T2D with some major classes of approved drugs that include Sulfonylureas, Meglitinides, Biguanides, Thiazolidinedione, Alpha-glucosidase inhibitors, GLP-1 analogs, DPP-4 Inhibitors, and SGLT2 inhibitors. This review focuses on the drug metabolizing enzymes (DME), gene polymorphisms, and inter-individual variability in therapeutics including adverse reaction effects involving Phase-I DME and Phase-II in general. This review also covers some key anti-diabetic drugs with respect to their pharcogenomics. PMID:26652255

  14. Possible drug–drug interaction in dogs and cats resulted from alteration in drug metabolism: A mini review

    PubMed Central

    Sasaki, Kazuaki; Shimoda, Minoru

    2015-01-01

    Pharmacokinetic drug–drug interactions (in particular at metabolism) may result in fatal adverse effects in some cases. This basic information, therefore, is needed for drug therapy even in veterinary medicine, as multidrug therapy is not rare in canines and felines. The aim of this review was focused on possible drug–drug interactions in dogs and cats. The interaction includes enzyme induction by phenobarbital, enzyme inhibition by ketoconazole and fluoroquinolones, and down-regulation of enzymes by dexamethasone. A final conclusion based upon the available literatures and author’s experience is given at the end of the review. PMID:26257936

  15. Prenatal drug exposure affects neonatal brain functional connectivity.

    PubMed

    Salzwedel, Andrew P; Grewen, Karen M; Vachet, Clement; Gerig, Guido; Lin, Weili; Gao, Wei

    2015-04-01

    Prenatal drug exposure, particularly prenatal cocaine exposure (PCE), incurs great public and scientific interest because of its associated neurodevelopmental consequences. However, the neural underpinnings of PCE remain essentially uncharted, and existing studies in school-aged children and adolescents are confounded greatly by postnatal environmental factors. In this study, leveraging a large neonate sample (N = 152) and non-invasive resting-state functional magnetic resonance imaging, we compared human infants with PCE comorbid with other drugs (such as nicotine, alcohol, marijuana, and antidepressant) with infants with similar non-cocaine poly drug exposure and drug-free controls. We aimed to characterize the neural correlates of PCE based on functional connectivity measurements of the amygdala and insula at the earliest stage of development. Our results revealed common drug exposure-related connectivity disruptions within the amygdala-frontal, insula-frontal, and insula-sensorimotor circuits. Moreover, a cocaine-specific effect was detected within a subregion of the amygdala-frontal network. This pathway is thought to play an important role in arousal regulation, which has been shown to be irregular in PCE infants and adolescents. These novel results provide the earliest human-based functional delineations of the neural-developmental consequences of prenatal drug exposure and thus open a new window for the advancement of effective strategies aimed at early risk identification and intervention.

  16. Prenatal drug exposure affects neonatal brain functional connectivity.

    PubMed

    Salzwedel, Andrew P; Grewen, Karen M; Vachet, Clement; Gerig, Guido; Lin, Weili; Gao, Wei

    2015-04-01

    Prenatal drug exposure, particularly prenatal cocaine exposure (PCE), incurs great public and scientific interest because of its associated neurodevelopmental consequences. However, the neural underpinnings of PCE remain essentially uncharted, and existing studies in school-aged children and adolescents are confounded greatly by postnatal environmental factors. In this study, leveraging a large neonate sample (N = 152) and non-invasive resting-state functional magnetic resonance imaging, we compared human infants with PCE comorbid with other drugs (such as nicotine, alcohol, marijuana, and antidepressant) with infants with similar non-cocaine poly drug exposure and drug-free controls. We aimed to characterize the neural correlates of PCE based on functional connectivity measurements of the amygdala and insula at the earliest stage of development. Our results revealed common drug exposure-related connectivity disruptions within the amygdala-frontal, insula-frontal, and insula-sensorimotor circuits. Moreover, a cocaine-specific effect was detected within a subregion of the amygdala-frontal network. This pathway is thought to play an important role in arousal regulation, which has been shown to be irregular in PCE infants and adolescents. These novel results provide the earliest human-based functional delineations of the neural-developmental consequences of prenatal drug exposure and thus open a new window for the advancement of effective strategies aimed at early risk identification and intervention. PMID:25855194

  17. Metformin revisited: Does this regulator of AMP-activated protein kinase secondarily affect bone metabolism and prevent diabetic osteopathy.

    PubMed

    McCarthy, Antonio Desmond; Cortizo, Ana María; Sedlinsky, Claudia

    2016-03-25

    Patients with long-term type 1 and type 2 diabetes mellitus (DM) can develop skeletal complications or "diabetic osteopathy". These include osteopenia, osteoporosis and an increased incidence of low-stress fractures. In this context, it is important to evaluate whether current anti-diabetic treatments can secondarily affect bone metabolism. Adenosine monophosphate-activated protein kinase (AMPK) modulates multiple metabolic pathways and acts as a sensor of the cellular energy status; recent evidence suggests a critical role for AMPK in bone homeostasis. In addition, AMPK activation is believed to mediate most clinical effects of the insulin-sensitizer metformin. Over the past decade, several research groups have investigated the effects of metformin on bone, providing a considerable body of pre-clinical (in vitro, ex vivo and in vivo) as well as clinical evidence for an anabolic action of metformin on bone. However, two caveats should be kept in mind when considering metformin treatment for a patient with type 2 DM at risk for diabetic osteopathy. In the first place, metformin should probably not be considered an anti-osteoporotic drug; it is an insulin sensitizer with proven macrovascular benefits that can secondarily improve bone metabolism in the context of DM. Secondly, we are still awaiting the results of randomized placebo-controlled studies in humans that evaluate the effects of metformin on bone metabolism as a primary endpoint.

  18. Metformin revisited: Does this regulator of AMP-activated protein kinase secondarily affect bone metabolism and prevent diabetic osteopathy

    PubMed Central

    McCarthy, Antonio Desmond; Cortizo, Ana María; Sedlinsky, Claudia

    2016-01-01

    Patients with long-term type 1 and type 2 diabetes mellitus (DM) can develop skeletal complications or “diabetic osteopathy”. These include osteopenia, osteoporosis and an increased incidence of low-stress fractures. In this context, it is important to evaluate whether current anti-diabetic treatments can secondarily affect bone metabolism. Adenosine monophosphate-activated protein kinase (AMPK) modulates multiple metabolic pathways and acts as a sensor of the cellular energy status; recent evidence suggests a critical role for AMPK in bone homeostasis. In addition, AMPK activation is believed to mediate most clinical effects of the insulin-sensitizer metformin. Over the past decade, several research groups have investigated the effects of metformin on bone, providing a considerable body of pre-clinical (in vitro, ex vivo and in vivo) as well as clinical evidence for an anabolic action of metformin on bone. However, two caveats should be kept in mind when considering metformin treatment for a patient with type 2 DM at risk for diabetic osteopathy. In the first place, metformin should probably not be considered an anti-osteoporotic drug; it is an insulin sensitizer with proven macrovascular benefits that can secondarily improve bone metabolism in the context of DM. Secondly, we are still awaiting the results of randomized placebo-controlled studies in humans that evaluate the effects of metformin on bone metabolism as a primary endpoint. PMID:27022443

  19. Respiratory muscle strength and muscle endurance are not affected by acute metabolic acidemia.

    PubMed

    Nizet, Tessa A C; Heijdra, Yvonne F; van den Elshout, Frank J J; van de Ven, Marjo J T; Bosch, Frank H; Mulder, Paul H; Folgering, Hans Th M

    2009-11-01

    Respiratory muscle fatigue in asthma and chronic obstructive lung disease (COPD) contributes to respiratory failure with hypercapnia, and subsequent respiratory acidosis. Therapeutic induction of acute metabolic acidosis further increases the respiratory drive and, therefore, may diminish ventilatory failure and hypercapnia. On the other hand, it is known that acute metabolic acidosis can also negatively affect (respiratory) muscle function and, therefore, could lead to a deterioration of respiratory failure. Moreover, we reasoned that the impact of metabolic acidosis on respiratory muscle strength and respiratory muscle endurance could be more pronounced in COPD patients as compared to asthma patients and healthy subjects, due to already impaired respiratory muscle function. In this study, the effect of metabolic acidosis was studied on peripheral muscle strength, peripheral muscle endurance, airway resistance, and on arterial carbon dioxide tension (PaCO(2)). Acute metabolic acidosis was induced by administration of ammonium chloride (NH(4)Cl). The effect of metabolic acidosis was studied on inspiratory and expiratory muscle strength and on respiratory muscle endurance. Effects were studied in a randomized, placebo-controlled cross-over design in 15 healthy subjects (4 male; age 33.2 +/- 11.5 years; FEV(1) 108.3 +/- 16.2% predicted), 14 asthma patients (5 male; age 48.1 +/- 16.1 years; FEV(1) 101.6 +/- 15.3% predicted), and 15 moderate to severe COPD patients (9 male; age 62.8 +/- 6.8 years; FEV(1) 50.0 +/- 11.8% predicted). An acute metabolic acidemia of BE -3.1 mmol x L(-1) was induced. Acute metabolic acidemia did not significantly affect strength or endurance of respiratory and peripheral muscles, respectively. In all subjects airway resistance was significantly decreased after induction of metabolic acidemia (mean difference -0.1 kPa x sec x L(-1) [95%-CI: -0.1 - -0.02]. In COPD patients PaCO(2) was significantly lowered during metabolic acidemia (mean

  20. Assessment of drug metabolism enzyme and transporter pharmacogenetics in drug discovery and early development: perspectives of the I-PWG.

    PubMed

    Brian, William; Tremaine, Larry M; Arefayene, Million; de Kanter, Ruben; Evers, Raymond; Guo, Yingying; Kalabus, James; Lin, Wen; Loi, Cho-Ming; Xiao, Guangqing

    2016-04-01

    Genetic variants of drug metabolism enzymes and transporters can result in high pharmacokinetic and pharmacodynamic variability, unwanted characteristics of efficacious and safe drugs. Ideally, the contributions of these enzymes and transporters to drug disposition can be predicted from in vitro experiments and in silico modeling in discovery or early development, and then be utilized during clinical development. Recently, regulatory agencies have provided guidance on the preclinical investigation of pharmacogenetics, for application to clinical drug development. This white paper summarizes the results of an industry survey conducted by the Industry Pharmacogenomics Working Group on current practice and challenges with using in vitro systems and in silico models to understand pharmacogenetic causes of variability in drug disposition.

  1. Application of chimeric mice with humanized liver for study of human-specific drug metabolism.

    PubMed

    Bateman, Thomas J; Reddy, Vijay G B; Kakuni, Masakazu; Morikawa, Yoshio; Kumar, Sanjeev

    2014-06-01

    Human-specific or disproportionately abundant human metabolites of drug candidates that are not adequately formed and qualified in preclinical safety assessment species pose an important drug development challenge. Furthermore, the overall metabolic profile of drug candidates in humans is an important determinant of their drug-drug interaction susceptibility. These risks can be effectively assessed and/or mitigated if human metabolic profile of the drug candidate could reliably be determined in early development. However, currently available in vitro human models (e.g., liver microsomes, hepatocytes) are often inadequate in this regard. Furthermore, the conduct of definitive radiolabeled human ADME studies is an expensive and time-consuming endeavor that is more suited for later in development when the risk of failure has been reduced. We evaluated a recently developed chimeric mouse model with humanized liver on uPA/SCID background for its ability to predict human disposition of four model drugs (lamotrigine, diclofenac, MRK-A, and propafenone) that are known to exhibit human-specific metabolism. The results from these studies demonstrate that chimeric mice were able to reproduce the human-specific metabolite profile for lamotrigine, diclofenac, and MRK-A. In the case of propafenone, however, the human-specific metabolism was not detected as a predominant pathway, and the metabolite profiles in native and humanized mice were similar; this was attributed to the presence of residual highly active propafenone-metabolizing mouse enzymes in chimeric mice. Overall, the data indicate that the chimeric mice with humanized liver have the potential to be a useful tool for the prediction of human-specific metabolism of xenobiotics and warrant further investigation.

  2. Metabolic signature identifies novel targets for drug resistance in Multiple Myeloma

    PubMed Central

    Maiso, Patricia; Huynh, Daisy; Moschetta, Michele; Sacco, Antonio; Aljawai, Yosra; Mishima, Yuji; Asara, John M.; Roccaro, Aldo M.; Kimmelman, Alec C.; Ghobrial, Irene M.

    2015-01-01

    Drug resistance remains a major clinical challenge for cancer treatment. Multiple myeloma (MM) is an incurable plasma cell cancer selectively localized in the bone marrow (BM). The main cause of resistance in myeloma is the minimal residual disease (MRD) cells that are resistant to the original therapy including bortezomib treatment and high dose melphalan in stem cell transplant. In this study, we demonstrate that altered tumor cell metabolism is essential for the regulation of drug resistance in MM cells. We show the unprecedented role of the metabolic phenotype in inducing drug resistance through LDHA and HIF1A in MM; and that specific inhibition of LDHA and HIF1A can restore sensitivity to therapeutic agents such as bortezomib and can also inhibit tumor growth induced by altered metabolism. Knockdown of LDHA can restore sensitivity of bortezomib resistance cell lines while gain of function studies using LDHA or HIF1A induced resistance in bortezomib sensitive cell lines. Taken together, these data suggest that HIF1A and LDHA are important targets for hypoxia-driven drug resistance. Novel drugs that regulate metabolic pathways in MM, specifically targeting LDHA, can be beneficial to inhibit tumor growth and overcome drug resistance. PMID:25769724

  3. Drug Metabolism by the Host and Gut Microbiota: A Partnership or Rivalry?

    PubMed Central

    2015-01-01

    The importance of the gut microbiome in determining not only overall health, but also in the metabolism of drugs and xenobiotics, is rapidly emerging. It is becoming increasingly clear that the gut microbiota can act in concert with the host cells to maintain intestinal homeostasis, cometabolize drugs and xenobiotics, and alter the expression levels of drug-metabolizing enzymes and transporters and the expression and activity levels of nuclear receptors. In this myriad of activities, the impact of the microbiota may be beneficial or detrimental to the host. Given that the interplay between the gut microbiota and host cells is likely subject to high interindividual variability, this work has tremendous implications for our ability to predict accurately a particular drug’s pharmacokinetics and a given patient population’s response to drugs. In this issue of Drug Metabolism and Disposition, a series of articles is presented that illustrate the progress and challenges that lie ahead as we unravel the intricacies associated with drug and xenobiotic metabolism by the gut microbiota. These articles highlight the underlying mechanisms that are involved and the use of in vivo and in vitro approaches that are currently available for elucidating the role of the gut microbiota in drug and xenobiotic metabolism. These articles also shed light on exciting new avenues of research that may be pursued as we consider the role of the gut microbiota as an endocrine organ, a component of the brain-gut axis, and whether the gut microbiota is an appropriate and amenable target for new drugs. PMID:26261284

  4. Drug Metabolism within the Brain Changes Drug Response: Selective Manipulation of Brain CYP2B Alters Propofol Effects

    PubMed Central

    Khokhar, Jibran Y; Tyndale, Rachel F

    2011-01-01

    Drug-metabolizing cytochrome P450 (CYPs) enzymes are expressed in the liver, as well as in extrahepatic tissues such as the brain. Here we show for the first time that drug metabolism by a CYP within the brain, illustrated using CYP2B and the anesthetic propofol (2, 6-diisopropylphenol, Diprivan), can meaningfully alter the pharmacological response to a CNS acting drug. CYP2B is expressed in the brains of animals and humans, and this CYP isoform is able to metabolize centrally acting substrates such as propofol, ecstasy, and serotonin. Rats were given intracerebroventricularly (i.c.v.) injections of vehicle, C8-xanthate, or 8-methoxypsoralen (CYP2B mechanism-based inhibitors) and then tested for sleep time following propofol (80 mg/kg intraperitoneally). Both inhibitors significantly increased sleep-time (1.8- to 2-fold) and brain propofol levels, while having no effect on plasma propofol levels. Seven days of nicotine treatment can induce the expression of brain, but not hepatic, CYP2B, and this induction reduced propofol sleep times by 2.5-fold. This reduction was reversed in a dose-dependent manner by i.c.v. injections of inhibitor. Sleep times correlated with brain (r=0.76, P=0.0009), but not plasma (r=0.24, P=0.39) propofol concentrations. Inhibitor treatments increased brain, but not plasma, propofol levels, and had no effect on hepatic enzyme activity. These data indicate that brain CYP2B can metabolize neuroactive substrates (eg, propofol) and can alter their pharmacological response. This has wider implications for localized CYP-mediated metabolism of drugs, neurotransmitters, and neurotoxins within the brain by this highly variable enzyme family and other CYP subfamilies expressed in the brain. PMID:21107310

  5. Feline drug metabolism and disposition: pharmacokinetic evidence for species differences and molecular mechanisms.

    PubMed

    Court, Michael H

    2013-09-01

    Although it is widely appreciated that cats respond differently to certain drugs compared with other companion animal species, the causes of these differences are poorly understood. This article evaluates published evidence for altered drug effects in cats, focusing on pharmacokinetic differences between cats, dogs, and humans, and the molecular mechanisms underlying these differences. More work is needed to better understand drug metabolism and disposition differences in cats, thereby enabling more rational prescribing of existing medications, and the development of safer drugs for this species.

  6. Disposition of a flow-limited drug (lidocaine) and a metabolic capacity-limited drug (theophylline) in liver cirrhosis.

    PubMed

    Colli, A; Buccino, G; Cocciolo, M; Parravicini, R; Scaltrini, G

    1988-12-01

    The plasma clearance after oral administration of a completely absorbed drug that is metabolized by the liver depends on its intrinsic clearance. In cirrhosis the bioavailability of a flow-dependent drug increases because of both portosystemic shunting and hepatocyte dysfunction. A drug with a high extraction ratio, lidocaine, and a drug with a low extraction ratio, theophylline, were administered to 27 patients with cirrhosis and 16 control subjects. We found a significant impairment of both theophylline clearance (p less than 0.001) and lidocaine clearance (p less than 0.001) and an increase in the lidocaine peak concentration (p less than 0.001). The three parameters were significantly correlated with each other. The impairment of theophylline metabolism did not correlate with other indexes of disease severity, whereas lidocaine clearance was lower and lidocaine peak level higher in patients with decompensated cirrhosis and evidence of portal hypertension. Thus impairment in lidocaine disposition, which reflects both hepatocyte dysfunction and portosystemic shunting, correlated closer with the severity of liver disease than did theophylline metabolism.

  7. Efficient drug metabolism strategy based on microsome-mesoporous organosilica nanoreactors.

    PubMed

    Fang, Xiaoni; Zhang, Peng; Qiao, Liang; Feng, Xiaoyan; Zhang, Xiangmin; Girault, Hubert H; Liu, Baohong

    2014-11-01

    A rapid and accurate in vitro drug metabolism strategy has been proposed based on the design of a biomimetic nanoreactor composed of amino-functionalized periodic mesoporous organosilica (NH2-PMO) and microsomes. The amphiphilic nature and positive charge of NH2-PMO make it highly suited for the immobilization of hydrophobic and negatively charged microsomes to form nanoreactors, which can in turn extract substrates from solutions. Such nanoreactors provide a suitable environment to confine multiple enzymes and substrates with high local concentrations, as well as to maintain their catalytic activities for rapid and highly effective drug metabolic reactions. Coupled with high-performance liquid chromatography-mass spectrometry analysis, the metabolites of nifedipine and testosterone were quantitatively characterized, and the reaction kinetics was evaluated. Both the metabolism conversion and reaction rate were significantly improved with the NH2-PMO nanoreactors compared to bulk reactions. This strategy is simple and cost-effective for promising advances in biomimetic metabolism study.

  8. Bioavailability of alcohol: role of gastric metabolism and its interaction with other drugs.

    PubMed

    Baraona, E; Gentry, R T; Lieber, C S

    1994-01-01

    In most individuals, only part of the imbibed alcohol reaches the systemic blood. With doses relevant to social drinking, this is due mainly to gastric first-pass metabolism of alcohol, which acts as a barrier against toxic alcohol blood levels. The activity of gastric alcohol dehydrogenase can account for a substantial fraction of this metabolism. Fasting, female gender, old age, dilution of alcoholic beverages, chronic alcohol consumption and still undetermined factors decrease the gastric metabolism of alcohol. Aspirin and some H2-receptor antagonists also inhibit this gastric activity. In subjects with documented first-pass metabolism, these drugs increase blood alcohol levels, especially after repeated small drinks, and may result in unexpected impairment to perform complex tasks, such as driving. Thus, patients treated with these drugs should be warned of this possible side effect.

  9. [Genetic polymorphism of FMO3 and its role in drug metabolism and toxicity].

    PubMed

    Gong, Zheng; Wang, Qi

    2015-07-01

    The flavin-containing monooxygenase 3 (FMO3) is an important hepatic microsomal enzyme. Numerous mutations of FMO3 gene have been reported, and polymorphic varients of the gene have been identified. Several studies indicated that variability in the expression of FMO3 involved in some nitrogen, or sulfur-containing durg metabolism. This review summarizes the genetic polymorphism of FMO3 and its role in drug metabolism and toxicity. PMID:26666012

  10. ECHS1 mutations in Leigh disease: a new inborn error of metabolism affecting valine metabolism.

    PubMed

    Peters, Heidi; Buck, Nicole; Wanders, Ronald; Ruiter, Jos; Waterham, Hans; Koster, Janet; Yaplito-Lee, Joy; Ferdinandusse, Sacha; Pitt, James

    2014-11-01

    Two siblings with fatal Leigh disease had increased excretion of S-(2-carboxypropyl)cysteine and several other metabolites that are features of 3-hydroxyisobutyryl-CoA hydrolase (HIBCH) deficiency, a rare defect in the valine catabolic pathway associated with Leigh-like disease. However, this diagnosis was excluded by HIBCH sequencing and normal enzyme activity. In contrast to HIBCH deficiency, the excretion of 3-hydroxyisobutyryl-carnitine was normal in the children, suggesting deficiency of short-chain enoyl-CoA hydratase (ECHS1 gene). This mitochondrial enzyme is active in several metabolic pathways involving fatty acids and amino acids, including valine, and is immediately upstream of HIBCH in the valine pathway. Both children were compound heterozygous for a c.473C > A (p.A158D) missense mutation and a c.414+3G>C splicing mutation in ECHS1. ECHS1 activity was markedly decreased in cultured fibroblasts from both siblings, ECHS1 protein was undetectable by immunoblot analysis and transfection of patient cells with wild-type ECHS1 rescued ECHS1 activity. The highly reactive metabolites methacrylyl-CoA and acryloyl-CoA accumulate in deficiencies of both ECHS1 and HIBCH and are probably responsible for the brain pathology in both disorders. Deficiency of ECHS1 or HIBCH should be considered in children with Leigh disease. Urine metabolite testing can detect and distinguish between these two disorders.

  11. Experimental Resistance to Drug Combinations in Leishmania donovani: Metabolic and Phenotypic Adaptations

    PubMed Central

    Berg, Maya; García-Hernández, Raquel; Cuypers, Bart; Vanaerschot, Manu; Manzano, José I.; Poveda, José A.; Ferragut, José A.; Castanys, Santiago

    2015-01-01

    Together with vector control, chemotherapy is an essential tool for the control of visceral leishmaniasis (VL), but its efficacy is jeopardized by growing resistance and treatment failure against first-line drugs. To delay the emergence of resistance, the use of drug combinations of existing antileishmanial agents has been tested systematically in clinical trials for the treatment of visceral leishmaniasis (VL). In vitro, Leishmania donovani promastigotes are able to develop experimental resistance to several combinations of different antileishmanial drugs after 10 weeks of drug pressure. Using an untargeted liquid chromatography-mass spectrometry (LC-MS) metabolomics approach, we identified metabolic changes in lines that were experimentally resistant to drug combinations and their respective single-resistant lines. This highlighted both collective metabolic changes (found in all combination therapy-resistant [CTR] lines) and specific ones (found in certain CTR lines). We demonstrated that single-resistant and CTR parasite cell lines show distinct metabolic adaptations, which all converge on the same defensive mechanisms that were experimentally validated: protection against drug-induced and external oxidative stress and changes in membrane fluidity. The membrane fluidity changes were accompanied by changes in drug uptake only in the lines that were resistant against drug combinations with antimonials, and surprisingly, drug accumulation was higher in these lines. Together, these results highlight the importance and the central role of protection against oxidative stress in the different resistant lines. Ultimately, these phenotypic changes might interfere with the mode of action of all drugs that are currently used for the treatment of VL and should be taken into account in drug development. PMID:25645828

  12. Structural specificity of mucosal-cell transport and metabolism of peptide drugs: implication for oral peptide drug delivery

    NASA Technical Reports Server (NTRS)

    Bai, J. P.; Amidon, G. L.

    1992-01-01

    The brush border membrane of intestinal mucosal cells contains a peptide carrier system with rather broad substrate specificity and various endo- and exopeptidase activities. Small peptide (di-/tripeptide)-type drugs with or without an N-terminal alpha-amino group, including beta-lactam antibiotics and angiotensin-converting enzyme (ACE) inhibitors, are transported by the peptide transporter. Polypeptide drugs are hydrolyzed by brush border membrane proteolytic enzymes to di-/tripeptides and amino acids. Therefore, while the intestinal brush border membrane has a carrier system facilitating the absorption of di-/tripeptide drugs, it is a major barrier limiting oral availability of polypeptide drugs. In this paper, the specificity of peptide transport and metabolism in the intestinal brush border membrane is reviewed.

  13. Electrochemical simulation of cocaine metabolism-a step toward predictive toxicology for drugs of abuse.

    PubMed

    Mielczarek, Przemystaw; Raoof, Hana; Kotlinska, Joltanta H; Stefanowicz, Piotr; Szewczuk, Zbigniew; Suder, Piotr; Silberring, Jerzy

    2014-01-01

    Knowledge of the metabolic pathways and biotransformation of the most popular drugs, such as cocaine, amphetamine, morphine and others, is crucial for the elucidation of their possible toxicity and mechanism of action in the human body. In vitro studies on metabolism are mainly based on the incubation of drugs with liver celL homogenate and utilizing Living animals. These methods need to be followed by isolation and detection of metabolic products, which makes these techniques time-consuming and technically demanding. We show here that the oxidative metabolism that occurs in the liver cells and is mainly caused by cytochrome P450 can be successfully mimicked with the electrochemical system [EC] connected on-line with electrospray ionization mass spectrometry. Cocaine was chosen as a model drug for these studies and was analyzed with a previously described system under various conditions using the boron-doped diamond working electrode. The results were compared with the number of metabolites generated by a standard procedure based on the reaction with the rat Liver microsomes. Two electrochemical products of cocaine oxidation were created, of which one was a natural metabolite of cocaine in the human body-norcocaine. The EC provides a promising platform for the screening of the addictive drug phase I metabolism. The metabolites can be directly analyzed by mass spectrometry or collected and separated by Liquid chromatog- raphy. No Liver cell homogenate or microsome is necessary to generate these metabolites, which simplifies separation of the mixtures and reduces time and costs of all experiments.

  14. Liver X receptors in lipid metabolism: opportunities for drug discovery.

    PubMed

    Hong, Cynthia; Tontonoz, Peter

    2014-06-01

    The liver X receptors (LXRs) are pivotal regulators of lipid homeostasis in mammals. These transcription factors control the expression of a battery of genes involved in the uptake, transport, efflux and excretion of cholesterol in a tissue-dependent manner. The identification of the LXRs, and an increased understanding of the mechanisms by which LXR signalling regulates lipid homeostasis in different tissues (including the liver, intestine and brain), has highlighted new opportunities for therapeutic intervention in human metabolism. New strategies for the pharmacological manipulation of LXRs and their target genes offer promise for the treatment of human diseases in which lipids have a central role, including atherosclerosis and Alzheimer's disease.

  15. The fibrate drug gemfibrozil disrupts lipoprotein metabolism in rainbow trout.

    PubMed

    Prindiville, John S; Mennigen, Jan A; Zamora, Jake M; Moon, Thomas W; Weber, Jean-Michel

    2011-03-15

    Gemfibrozil (GEM) is a fibrate drug consistently found in effluents from sewage treatment plants. This study characterizes the pharmacological effects of GEM on the plasma lipoproteins of rainbow trout (Oncorhynchus mykiss). Our goals were to quantify the impact of the drug on: 1) lipid constituents of lipoproteins (phospholipids (PL), triacylglycerol (TAG), and cholesterol), 2) lipoprotein classes (high, low and very low density lipoproteins), and 3) fatty acid composition of lipoproteins. Potential mechanisms of GEM action were investigated by measuring lipoprotein lipase activity (LPL) and the hepatic gene expression of LPL and of the peroxisome proliferator-activated receptor (PPAR) α, β, and γ isoforms. GEM treatment resulted in decreased plasma lipoprotein levels (-29%) and a reduced size of all lipoprotein classes (lower PL:TAG ratios). However, the increase in HDL-cholesterol elicited by GEM in humans failed to be observed in trout. Therefore, HDL-cholesterol cannot be used to assess the impact of the drug on fish. GEM also modified lipoprotein composition by reducing the abundance of long-chain n-3 fatty acids, thereby potentially reducing the nutritional quality of exposed fish. The relative gene expression of LPL was increased, but the activity of the enzyme was not, and we found no evidence for the activation of PPAR pathways. The depressing effects of GEM on fish lipoproteins demonstrated here may be a concern in view of the widespread presence of fibrates in aquatic environments. Work is needed to test whether exposure to environmental concentrations of these drugs jeopardizes the capacity of fish for reproduction, temperature acclimation or migratory behaviors. PMID:21195106

  16. The fibrate drug gemfibrozil disrupts lipoprotein metabolism in rainbow trout

    SciTech Connect

    Prindiville, John S. Mennigen, Jan A.; Zamora, Jake M.; Moon, Thomas W.; Weber, Jean-Michel

    2011-03-15

    Gemfibrozil (GEM) is a fibrate drug consistently found in effluents from sewage treatment plants. This study characterizes the pharmacological effects of GEM on the plasma lipoproteins of rainbow trout (Oncorhynchus mykiss). Our goals were to quantify the impact of the drug on: 1) lipid constituents of lipoproteins (phospholipids (PL), triacylglycerol (TAG), and cholesterol), 2) lipoprotein classes (high, low and very low density lipoproteins), and 3) fatty acid composition of lipoproteins. Potential mechanisms of GEM action were investigated by measuring lipoprotein lipase activity (LPL) and the hepatic gene expression of LPL and of the peroxisome proliferator-activated receptor (PPAR) {alpha}, {beta}, and {gamma} isoforms. GEM treatment resulted in decreased plasma lipoprotein levels (- 29%) and a reduced size of all lipoprotein classes (lower PL:TAG ratios). However, the increase in HDL-cholesterol elicited by GEM in humans failed to be observed in trout. Therefore, HDL-cholesterol cannot be used to assess the impact of the drug on fish. GEM also modified lipoprotein composition by reducing the abundance of long-chain n-3 fatty acids, thereby potentially reducing the nutritional quality of exposed fish. The relative gene expression of LPL was increased, but the activity of the enzyme was not, and we found no evidence for the activation of PPAR pathways. The depressing effects of GEM on fish lipoproteins demonstrated here may be a concern in view of the widespread presence of fibrates in aquatic environments. Work is needed to test whether exposure to environmental concentrations of these drugs jeopardizes the capacity of fish for reproduction, temperature acclimation or migratory behaviors.

  17. Emerging Drugs and Indications for Cardio-Metabolic Disorders in People with Severe Mental Illness.

    PubMed

    Kouidrat, Youssef; Amad, Ali; De Hert, Marc

    2015-01-01

    Patients with severe mental illnesses, such as schizophrenia and bipolar disorder, are at increased risk of developing metabolic disorders including obesity, diabetes, and dyslipidemia. All of these comorbidities increase the risk of cardiovascular disease and mortality. Different approaches, including diet and lifestyle modifications, behavioral therapy and switching antipsychotic agents, have been proposed to manage these metabolic abnormalities. However, these interventions may be insufficient, impractical or fail to counteract the metabolic dysregulation. Consequently, a variety of pharmacological agents such as antidiabetic drugs, have been studied in an attempt to reverse the weight gain and metabolic abnormalities evident in these patients. Despite a significant effect, many of these treatments are used off-label. This qualitative review focuses on pharmacological agents that could offer significant benefits in the management of cardio-metabolic disorders associated with serious mental illness. PMID:26088113

  18. The antiepileptic drug carbamazepine affects sodium transport in toad epithelium.

    PubMed

    Suwalsky, Mario; Mennickent, Sigrid; Norris, Beryl; Cardenas, Hernán

    2006-09-01

    The present work investigates the effects of the antiepileptic drug carbamazepine (CBZ) on sodium transport in the isolated skin of the toad Pleurodema thaul. A submaximal concentration of the drug (0.2 mM) applied to the outer surface of the epithelium increased the electrical parameters short-circuit current (Isc) and potential difference (PD) by over 28%, whereas only a higher concentration (1 mM) induced over a 45% decrease in these parameters when applied to the inner surface. The amiloride test showed that the outer surface stimulatory effect was accompanied by an increase and the inner surface inhibitory effect by a decrease in the sodium electromotive force (ENa). Exploration of these effects of CBZ on the outer surface showed that 0.2 mM increased net Na+ (22Na) influx by 20% and 0.6 mM CBZ decreased Na+ mucosa-serosa flux by 19%, a result in agreement with the finding that higher concentrations of CBZ applied to the inner surface not only decreased ENa but also sodium conductance (GNa). PMID:16542818

  19. [POSSIBLE DRUG CORRECTION OF LIPID METABOLISM DISTURBANCES ASSOCIATED WITH METABOLIC SYNDROME IN PATIENTS WITH PSORIASIS].

    PubMed

    Dontsova, E V

    2015-01-01

    It was studied the possibility of correcting lipid metabolism in patients with psoriasis and concomitant metabolic syndrome (MS) by using additional treatment with semax. In group 1, 58 patients received conventional therapy, while 60 patients in group 2 received the same with additional 0.1% semax solution intranasally 600 mg/day for 10 days. It was found that the inclusion of semax in complex treatment of patients with psoriasis complicated by metabolic syndrome led to a decrease in the initially elevated serum levels of total cholesterol, triglycerides, LDL cholesterol and to an increase in the initially reduced levels of HDL cholesterol, in contrast to the standard treatment, which did not produce any statistically significant effect on the levels of total cholesterol, triglycerides, LDL cholesterol, and HDL cholesterol in the blood serum.

  20. Metabolism of ATP-binding cassette drug transporter inhibitors: complicating factor for multidrug resistance.

    PubMed

    Cnubben, Nicole H P; Wortelboer, Heleen M; van Zanden, Jelmer J; Rietjens, Ivonne M C M; van Bladeren, Peter J

    2005-08-01

    Membrane transport proteins belonging to the ATP-binding cassette (ABC) family of transport proteins play a central role in the defence of organisms against toxic compounds, including anticancer drugs. However, for compounds that are designed to display a toxic effect, this defence system diminishes their effectiveness. This is typically the case in the development of cellular resistance to anticancer drugs. Inhibitors of these transporters are thus potentially useful tools to reverse this transporter-mediated cellular resistance to anticancer drugs and, eventually, to enhance the effectiveness of the treatment of patients with drug-resistant cancer. This review highlights the various types of inhibitors of several multidrug resistance-related ABC proteins, and demonstrates that the metabolism of inhibitors, as illustrated by recent data obtained for various natural compound inhibitors, may have considerable implications for their effect on drug transport and their potential for treatment of drug resistance.

  1. Human Food Safety Implications of Variation in Food Animal Drug Metabolism

    PubMed Central

    Lin, Zhoumeng; Vahl, Christopher I.; Riviere, Jim E.

    2016-01-01

    Violative drug residues in animal-derived foods are a global food safety concern. The use of a fixed main metabolite to parent drug (M/D) ratio determined in healthy animals to establish drug tolerances and withdrawal times in diseased animals results in frequent residue violations in food-producing animals. We created a general physiologically based pharmacokinetic model for representative drugs (ceftiofur, enrofloxacin, flunixin, and sulfamethazine) in cattle and swine based on extensive published literature. Simulation results showed that the M/D ratio was not a fixed value, but a time-dependent range. Disease changed M/D ratios substantially and extended withdrawal times; these effects exhibited drug- and species-specificity. These results challenge the interpretation of violative residues based on the use of the M/D ratio to establish tolerances for metabolized drugs. PMID:27302389

  2. Metabolic Dysregulation Induced in Plasmodium falciparum by Dihydroartemisinin and Other Front-Line Antimalarial Drugs.

    PubMed

    Cobbold, Simon A; Chua, Hwa H; Nijagal, Brunda; Creek, Darren J; Ralph, Stuart A; McConville, Malcolm J

    2016-01-15

    Detailed information on the mode of action of antimalarial drugs can be used to improve existing drugs, identify new drug targets, and understand the basis of drug resistance. In this study we describe the use of a time-resolved, mass spectrometry (MS)-based metabolite profiling approach to map the metabolic perturbations induced by a panel of clinical antimalarial drugs and inhibitors on Plasmodium falciparum asexual blood stages. Drug-induced changes in metabolite levels in P. falciparum-infected erythrocytes were monitored over time using gas chromatography-MS and liquid chromatography-MS and changes in specific metabolic fluxes confirmed by nonstationary [(13)C]-glucose labeling. Dihydroartemisinin (DHA) was found to disrupt hemoglobin catabolism within 1 hour of exposure, resulting in a transient decrease in hemoglobin-derived peptides. Unexpectedly, it also disrupted pyrimidine biosynthesis, resulting in increased [(13)C]-glucose flux toward malate production, potentially explaining the susceptibility of P. falciparum to DHA during early blood-stage development. Unique metabolic signatures were also found for atovaquone, chloroquine, proguanil, cycloguanil and methylene blue. We also show that this approach can be used to identify the mode of action of novel antimalarials, such as the compound Torin 2, which inhibits hemoglobin catabolism. PMID:26150544

  3. Stretching Your Energetic Budget: How Tendon Compliance Affects the Metabolic Cost of Running

    PubMed Central

    Uchida, Thomas K.; Hicks, Jennifer L.; Dembia, Christopher L.; Delp, Scott L.

    2016-01-01

    Muscles attach to bones via tendons that stretch and recoil, affecting muscle force generation and metabolic energy consumption. In this study, we investigated the effect of tendon compliance on the metabolic cost of running using a full-body musculoskeletal model with a detailed model of muscle energetics. We performed muscle-driven simulations of running at 2–5 m/s with tendon force–strain curves that produced between 1 and 10% strain when the muscles were developing maximum isometric force. We computed the average metabolic power consumed by each muscle when running at each speed and with each tendon compliance. Average whole-body metabolic power consumption increased as running speed increased, regardless of tendon compliance, and was lowest at each speed when tendon strain reached 2–3% as muscles were developing maximum isometric force. When running at 2 m/s, the soleus muscle consumed less metabolic power at high tendon compliance because the strain of the tendon allowed the muscle fibers to operate nearly isometrically during stance. In contrast, the medial and lateral gastrocnemii consumed less metabolic power at low tendon compliance because less compliant tendons allowed the muscle fibers to operate closer to their optimal lengths during stance. The software and simulations used in this study are freely available at simtk.org and enable examination of muscle energetics with unprecedented detail. PMID:26930416

  4. A Key Role for Old Yellow Enzyme in the Metabolism of Drugs by Trypanosoma cruzi

    PubMed Central

    Kubata, Bruno Kilunga; Kabututu, Zakayi; Nozaki, Tomoyoshi; Munday, Craig J.; Fukuzumi, Shunichi; Ohkubo, Kei; Lazarus, Michael; Maruyama, Toshihiko; Martin, Samuel K.; Duszenko, Michael; Urade, Yoshihiro

    2002-01-01

    Trypanosoma cruzi is the etiological agent of Chagas' disease. So far, first choice anti-chagasic drugs in use have been shown to have undesirable side effects in addition to the emergence of parasite resistance and the lack of prospect for vaccine against T. cruzi infection. Thus, the isolation and characterization of molecules essential in parasite metabolism of the anti-chagasic drugs are fundamental for the development of new strategies for rational drug design and/or the improvement of the current chemotherapy. While searching for a prostaglandin (PG) F2α synthase homologue, we have identified a novel “old yellow enzyme” from T. cruzi (TcOYE), cloned its cDNA, and overexpressed the recombinant enzyme. Here, we show that TcOYE reduced 9,11-endoperoxide PGH2 to PGF2α as well as a variety of trypanocidal drugs. By electron spin resonance experiments, we found that TcOYE specifically catalyzed one-electron reduction of menadione and β-lapachone to semiquinone-free radicals with concomitant generation of superoxide radical anions, while catalyzing solely the two-electron reduction of nifurtimox and 4-nitroquinoline-N-oxide drugs without free radical production. Interestingly, immunoprecipitation experiments revealed that anti-TcOYE polyclonal antibody abolished major reductase activities of the lysates toward these drugs, identifying TcOYE as a key drug-metabolizing enzyme by which quinone drugs have their mechanism of action. PMID:12417633

  5. Xylitol Affects the Intestinal Microbiota and Metabolism of Daidzein in Adult Male Mice

    PubMed Central

    Tamura, Motoi; Hoshi, Chigusa; Hori, Sachiko

    2013-01-01

    This study examined the effects of xylitol on mouse intestinal microbiota and urinary isoflavonoids. Xylitol is classified as a sugar alcohol and used as a food additive. The intestinal microbiota seems to play an important role in isoflavone metabolism. Xylitol feeding appears to affect the gut microbiota. We hypothesized that dietary xylitol changes intestinal microbiota and, therefore, the metabolism of isoflavonoids in mice. Male mice were randomly divided into two groups: those fed a 0.05% daidzein with 5% xylitol diet (XD group) and those fed a 0.05% daidzein-containing control diet (CD group) for 28 days. Plasma total cholesterol concentrations were significantly lower in the XD group than in the CD group (p < 0.05). Urinary amounts of equol were significantly higher in the XD group than in the CD group (p < 0.05). The fecal lipid contents (% dry weight) were significantly greater in the XD group than in the CD group (p < 0.01). The cecal microbiota differed between the two dietary groups. The occupation ratios of Bacteroides were significantly greater in the CD than in the XD group (p < 0.05). This study suggests that xylitol has the potential to affect the metabolism of daidzein by altering the metabolic activity of the intestinal microbiota and/or gut environment. Given that equol affects bone health, dietary xylitol plus isoflavonoids may exert a favorable effect on bone health. PMID:24336061

  6. Xylitol affects the intestinal microbiota and metabolism of daidzein in adult male mice.

    PubMed

    Tamura, Motoi; Hoshi, Chigusa; Hori, Sachiko

    2013-12-10

    This study examined the effects of xylitol on mouse intestinal microbiota and urinary isoflavonoids. Xylitol is classified as a sugar alcohol and used as a food additive. The intestinal microbiota seems to play an important role in isoflavone metabolism. Xylitol feeding appears to affect the gut microbiota. We hypothesized that dietary xylitol changes intestinal microbiota and, therefore, the metabolism of isoflavonoids in mice. Male mice were randomly divided into two groups: those fed a 0.05% daidzein with 5% xylitol diet (XD group) and those fed a 0.05% daidzein-containing control diet (CD group) for 28 days. Plasma total cholesterol concentrations were significantly lower in the XD group than in the CD group (p < 0.05). Urinary amounts of equol were significantly higher in the XD group than in the CD group (p < 0.05). The fecal lipid contents (% dry weight) were significantly greater in the XD group than in the CD group (p < 0.01). The cecal microbiota differed between the two dietary groups. The occupation ratios of Bacteroides were significantly greater in the CD than in the XD group (p < 0.05). This study suggests that xylitol has the potential to affect the metabolism of daidzein by altering the metabolic activity of the intestinal microbiota and/or gut environment. Given that equol affects bone health, dietary xylitol plus isoflavonoids may exert a favorable effect on bone health.

  7. Exogenous cannabinoids as substrates, inhibitors, and inducers of human drug metabolizing enzymes: a systematic review.

    PubMed

    Stout, Stephen M; Cimino, Nina M

    2014-02-01

    Exogenous cannabinoids are structurally and pharmacologically diverse compounds that are widely used. The purpose of this systematic review is to summarize the data characterizing the potential for these compounds to act as substrates, inhibitors, or inducers of human drug metabolizing enzymes, with the aim of clarifying the significance of these properties in clinical care and drug interactions. In vitro data were identified that characterize cytochrome P-450 (CYP-450) enzymes as potential significant contributors to the primary metabolism of several exogenous cannabinoids: tetrahydrocannabinol (THC; CYPs 2C9, 3A4); cannabidiol (CBD; CYPs 2C19, 3A4); cannabinol (CBN; CYPs 2C9, 3A4); JWH-018 (CYPs 1A2, 2C9); and AM2201 (CYPs 1A2, 2C9). CYP-450 enzymes may also contribute to the secondary metabolism of THC, and UDP-glucuronosyltransferases have been identified as capable of catalyzing both primary (CBD, CBN) and secondary (THC, JWH-018, JWH-073) cannabinoid metabolism. Clinical pharmacogenetic data further support CYP2C9 as a significant contributor to THC metabolism, and a pharmacokinetic interaction study using ketoconazole with oromucosal cannabis extract further supports CYP3A4 as a significant metabolic pathway for THC and CBD. However, the absence of interaction between CBD from oromucosal cannabis extract with omeprazole suggests a less significant role of CYP2C19 in CBD metabolism. Studies of THC, CBD, and CBN inhibition and induction of major human CYP-450 isoforms generally reflect a low risk of clinically significant drug interactions with most use, but specific human data are lacking. Smoked cannabis herb (marijuana) likely induces CYP1A2 mediated theophylline metabolism, although the role of cannabinoids specifically in eliciting this effect is questionable.

  8. Activation of CAR and PXR by Dietary, Environmental and Occupational Chemicals Alters Drug Metabolism, Intermediary Metabolism, and Cell Proliferation

    PubMed Central

    Hernandez, J.P.; Mota, L.C.; Baldwin, W.S.

    2010-01-01

    The constitutive androstane receptor (CAR) and the pregnane × receptor (PXR) are activated by a variety of endogenous and exogenous ligands, such as steroid hormones, bile acids, pharmaceuticals, and environmental, dietary, and occupational chemicals. In turn, they induce phase I–III detoxification enzymes and transporters that help eliminate these chemicals. Because many of the chemicals that activate CAR and PXR are environmentally-relevant (dietary and anthropogenic), studies need to address whether these chemicals or mixtures of these chemicals may increase the susceptibility to adverse drug interactions. In addition, CAR and PXR are involved in hepatic proliferation, intermediary metabolism, and protection from cholestasis. Therefore, activation of CAR and PXR may have a wide variety of implications for personalized medicine through physiological effects on metabolism and cell proliferation; some beneficial and others adverse. Identifying the chemicals that activate these promiscuous nuclear receptors and understanding how these chemicals may act in concert will help us predict adverse drug reactions (ADRs), predict cholestasis and steatosis, and regulate intermediary metabolism. This review summarizes the available data on CAR and PXR, including the environmental chemicals that activate these receptors, the genes they control, and the physiological processes that are perturbed or depend on CAR and PXR action. This knowledge contributes to a foundation that will be necessary to discern interindividual differences in the downstream biological pathways regulated by these key nuclear receptors. PMID:20871735

  9. Major diet-drug interactions affecting the kinetic characteristics and hypolipidaemic properties of statins.

    PubMed

    Vaquero, M P; Sánchez Muniz, F J; Jiménez Redondo, S; Prats Oliván, P; Higueras, F J; Bastida, S

    2010-01-01

    Concomitant administration of statins with food may alter statin pharmacokinetics or pharmacodynamics, increasing the risk of adverse reactions such as myopathy or rhabdomyolysis or reducing their pharmacological action. This paper reviews major interactions between statins and dietary compounds. Consumption of pectin or oat bran together with Lovastatin reduces absorption of the drug, while alcohol intake does not appear to affect the efficacy and safety of Fluvastatin treatment. Grapefruit juice components inhibit cytochrome P-4503A4, reducing the presystemic metabolism of drugs such as Simvastatin, Lovastatin and Atorvastatin. Follow-up studies on the therapeutic effect of statins in patients consuming a Mediterranean-style diet are necessary to assure the correct prescription because the oil-statin and minor oil compound-statin possible interactions have been only briefly studied. Preliminary study suggests that olive oil can increase the hypolipaemiant effect of Simvastatin with respect sunflower oil. The consumption of polyunsaturated rich oils, throughout the cytochrome P- 450 activation could decrease the half-life of some statins and therefore their hypolipaemic effects. The statins and n-3 fatty acids combined therapy gives rise to pharmacodinamic interaction that improves the lipid profile and leads greater cardioprotection. Although statins are more effective in high endogenous cholesterol production subjects and plant sterols are more effective in high cholesterol absorption efficacy subjects, plant esterols-statins combined therapy generates very positive complementary effects. This review ends suggesting possible diet-stain interactions that require further investigations (e.g. types of olive oils, fruit juices other than grapefruit, fibre or consumption of alcoholic beverages rich in polyphenols or ethanol).

  10. Major diet-drug interactions affecting the kinetic characteristics and hypolipidaemic properties of statins.

    PubMed

    Vaquero, M P; Sánchez Muniz, F J; Jiménez Redondo, S; Prats Oliván, P; Higueras, F J; Bastida, S

    2010-01-01

    Concomitant administration of statins with food may alter statin pharmacokinetics or pharmacodynamics, increasing the risk of adverse reactions such as myopathy or rhabdomyolysis or reducing their pharmacological action. This paper reviews major interactions between statins and dietary compounds. Consumption of pectin or oat bran together with Lovastatin reduces absorption of the drug, while alcohol intake does not appear to affect the efficacy and safety of Fluvastatin treatment. Grapefruit juice components inhibit cytochrome P-4503A4, reducing the presystemic metabolism of drugs such as Simvastatin, Lovastatin and Atorvastatin. Follow-up studies on the therapeutic effect of statins in patients consuming a Mediterranean-style diet are necessary to assure the correct prescription because the oil-statin and minor oil compound-statin possible interactions have been only briefly studied. Preliminary study suggests that olive oil can increase the hypolipaemiant effect of Simvastatin with respect sunflower oil. The consumption of polyunsaturated rich oils, throughout the cytochrome P- 450 activation could decrease the half-life of some statins and therefore their hypolipaemic effects. The statins and n-3 fatty acids combined therapy gives rise to pharmacodinamic interaction that improves the lipid profile and leads greater cardioprotection. Although statins are more effective in high endogenous cholesterol production subjects and plant sterols are more effective in high cholesterol absorption efficacy subjects, plant esterols-statins combined therapy generates very positive complementary effects. This review ends suggesting possible diet-stain interactions that require further investigations (e.g. types of olive oils, fruit juices other than grapefruit, fibre or consumption of alcoholic beverages rich in polyphenols or ethanol). PMID:20449528

  11. Controllability in cancer metabolic networks according to drug targets as driver nodes.

    PubMed

    Asgari, Yazdan; Salehzadeh-Yazdi, Ali; Schreiber, Falk; Masoudi-Nejad, Ali

    2013-01-01

    Networks are employed to represent many nonlinear complex systems in the real world. The topological aspects and relationships between the structure and function of biological networks have been widely studied in the past few decades. However dynamic and control features of complex networks have not been widely researched, in comparison to topological network features. In this study, we explore the relationship between network controllability, topological parameters, and network medicine (metabolic drug targets). Considering the assumption that targets of approved anticancer metabolic drugs are driver nodes (which control cancer metabolic networks), we have applied topological analysis to genome-scale metabolic models of 15 normal and corresponding cancer cell types. The results show that besides primary network parameters, more complex network metrics such as motifs and clusters may also be appropriate for controlling the systems providing the controllability relationship between topological parameters and drug targets. Consequently, this study reveals the possibilities of following a set of driver nodes in network clusters instead of considering them individually according to their centralities. This outcome suggests considering distributed control systems instead of nodal control for cancer metabolic networks, leading to a new strategy in the field of network medicine.

  12. Controllability in Cancer Metabolic Networks According to Drug Targets as Driver Nodes

    PubMed Central

    Asgari, Yazdan; Salehzadeh-Yazdi, Ali; Schreiber, Falk; Masoudi-Nejad, Ali

    2013-01-01

    Networks are employed to represent many nonlinear complex systems in the real world. The topological aspects and relationships between the structure and function of biological networks have been widely studied in the past few decades. However dynamic and control features of complex networks have not been widely researched, in comparison to topological network features. In this study, we explore the relationship between network controllability, topological parameters, and network medicine (metabolic drug targets). Considering the assumption that targets of approved anticancer metabolic drugs are driver nodes (which control cancer metabolic networks), we have applied topological analysis to genome-scale metabolic models of 15 normal and corresponding cancer cell types. The results show that besides primary network parameters, more complex network metrics such as motifs and clusters may also be appropriate for controlling the systems providing the controllability relationship between topological parameters and drug targets. Consequently, this study reveals the possibilities of following a set of driver nodes in network clusters instead of considering them individually according to their centralities. This outcome suggests considering distributed control systems instead of nodal control for cancer metabolic networks, leading to a new strategy in the field of network medicine. PMID:24282504

  13. Deletion of 30 murine cytochrome p450 genes results in viable mice with compromised drug metabolism.

    PubMed

    Scheer, Nico; McLaughlin, Lesley A; Rode, Anja; Macleod, A Kenneth; Henderson, Colin J; Wolf, C Roland

    2014-06-01

    In humans, 75% of all drugs are metabolized by the cytochrome P450-dependent monooxygenase system. Enzymes encoded by the CYP2C, CYP2D, and CYP3A gene clusters account for ∼80% of this activity. There are profound species differences in the multiplicity of cytochrome P450 enzymes, and the use of mouse models to predict pathways of drug metabolism is further complicated by overlapping substrate specificity between enzymes from different gene families. To establish the role of the hepatic and extrahepatic P450 system in drug and foreign chemical disposition, drug efficacy, and toxicity, we created a unique mouse model in which 30 cytochrome P450 genes from the Cyp2c, Cyp2d, and Cyp3a gene clusters have been deleted. Remarkably, despite a wide range of putative important endogenous functions, Cyp2c/2d/3a KO mice were viable and fertile, demonstrating that these genes have evolved primarily as detoxification enzymes. Although there was no overt phenotype, detailed examination showed Cyp2c/2d/3a KO mice had a smaller body size (15%) and larger livers (20%). Changes in hepatic morphology and a decreased blood glucose (30%) were also noted. A five-drug cocktail of cytochrome P450 isozyme probe substrates were used to evaluate changes in drug pharmacokinetics; marked changes were observed in either the pharmacokinetics or metabolites formed from Cyp2c, Cyp2d, and Cyp3a substrates, whereas the metabolism of the Cyp1a substrate caffeine was unchanged. Thus, Cyp2c/2d/3a KO mice provide a powerful model to study the in vivo role of the P450 system in drug metabolism and efficacy, as well as in chemical toxicity. PMID:24671958

  14. Redox-based epigenetic status in drug addiction: a potential contributor to gene priming and a mechanistic rationale for metabolic intervention

    PubMed Central

    Trivedi, Malav S.; Deth, Richard

    2015-01-01

    Alcohol and other drugs of abuse, including psychostimulants and opioids, can induce epigenetic changes: a contributing factor for drug addiction, tolerance, and associated withdrawal symptoms. DNA methylation is a major epigenetic mechanism and it is one of more than 200 methylation reactions supported by methyl donor S-adenosylmethionine (SAM). Levels of SAM are controlled by cellular redox status via the folate and vitamin B12-dependent enzyme methionine synthase (MS). For example, under oxidative conditions MS is inhibited, diverting its substrate homocysteine (HCY) to the trans sulfuration pathway. Alcohol, dopamine, and morphine, can alter intracellular levels of glutathione (GSH)-based cellular redox status, subsequently affecting SAM levels and DNA methylation status. Here, existing evidence is presented in a coherent manner to propose a novel hypothesis implicating the involvement of redox-based epigenetic changes in drug addiction. Further, we discuss how a “gene priming” phenomenon can contribute to the maintenance of redox and methylation status homeostasis under various stimuli including drugs of abuse. Additionally, a new mechanistic rationale for the use of metabolic interventions/redox-replenishers as symptomatic treatment of alcohol and other drug addiction and associated withdrawal symptoms is also provided. Hence, the current review article strengthens the hypothesis that neuronal metabolism has a critical bidirectional coupling with epigenetic changes in drug addiction exemplified by the link between redox-based metabolic changes and resultant epigenetic consequences under the effect of drugs of abuse. PMID:25657617

  15. Fasting-Induced Changes in Hepatic P450 Mediated Drug Metabolism Are Largely Independent of the Constitutive Androstane Receptor CAR

    PubMed Central

    de Vries, E. M.; Lammers, L. A.; Achterbergh, R.; Klümpen, H-J; Mathot, R. A. A.; Boelen, A.; Romijn, J. A.

    2016-01-01

    Introduction Hepatic drug metabolism by cytochrome P450 enzymes is altered by the nutritional status of patients. The expression of P450 enzymes is partly regulated by the constitutive androstane receptor (CAR). Fasting regulates the expression of both P450 enzymes and CAR and affects hepatic drug clearance. We hypothesized that the fasting-induced alterations in P450 mediated drug clearance are mediated by CAR. Methods To investigate this we used a drug cocktail validated in humans consisting of five widely prescribed drugs as probes for specific P450 enzymes: caffeine (CYP1A2), metoprolol (CYP2D6), omeprazole (CYP2C19), midazolam (CYP3A4) and s-warfarin (CYP2C9). This cocktail was administered to wild type (WT, C57Bl/6) mice or mice deficient for CAR (CAR-/-) that were either fed ad libitum or fasted for 24 hours. Blood was sampled at predefined intervals and drug concentrations were measured as well as hepatic mRNA expression of homologous/orthologous P450 enzymes (Cyp1a2, Cyp2d22, Cyp3a11, Cyp2c37, Cyp2c38 and Cyp2c65). Results Fasting decreased Cyp1a2 and Cyp2d22 expression and increased Cyp3a11 and Cyp2c38 expression in both WT and CAR-/- mice. The decrease in Cyp1a2 was diminished in CAR-/- in comparison with WT mice. Basal Cyp2c37 expression was lower in CAR-/- compared to WT mice. Fasting decreased the clearance of all drugs tested in both WT and CAR-/- mice. The absence of CAR was associated with an decrease in the clearance of omeprazole, metoprolol and midazolam in fed mice. The fasting-induced reduction in clearance of s-warfarin was greater in WT than in CAR-/-. The changes in drug clearance correlated with the expression pattern of the specific P450 enzymes in case of Cyp1a2-caffeine and Cyp2c37-omeprazole. Conclusion We conclude that CAR is important for hepatic clearance of several widely prescribed drugs metabolized by P450 enzymes. However the fasting-induced alterations in P450 mediated drug clearance are largely independent of CAR. PMID

  16. Influence of gallic acid esters on drug-metabolizing enzymes of rat liver.

    PubMed

    Depner, M; Kahl, G F; Kahl, R

    1982-10-01

    The effect of three antioxidants, propyl, octyl and dodecyl gallate, on hepatic drug metabolism in male rats was studied in vivo and in vitro. When fed at a dietary concentration of 1% for 14 days, only dodecyl gallate increased relative liver weight. Cytochrome P-450 content was not influenced, but a slight increase in cytochrome b5 content was observed after the feeding of propyl gallate. Monooxygenase activity (benzo[a]pyrene-hydroxylase and ethoxycoumarin-deethylase activities) was not affected by propyl or octyl gallate, but a significant decrease in benzo[a]pyrene-hydroxylase activity was apparent in rats fed dodecyl gallate. Study of benzo[a]pyrene-metabolite formation in liver microsome preparations from control and propyl gallate-treated rats showed an overall decrease in metabolite production following gallate treatment, the decrease being statistically significant for the formation of the 9,10-dihydrodiol. Epoxide-hydratase activity was enhanced by a factor of 1.5 in rats fed propyl gallate; glutathione-transferase activity was unaffected. In vitro, the gallates proved to be potent inhibitors of ethoxycoumarin deethylation in liver microsomes from untreated and phenobarbital-treated rats; however, when cytochrome P-448 had been induced by pretreatment with 3-methylcholanthrene, ethoxycoumarin deethylase was less sensitive to the inhibitory action of the gallates.

  17. The antiepileptic drug phenytoin affects sodium transport in toad epithelium.

    PubMed

    Suwalsky, Mario; Mennickent, Sigrid; Norris, Beryl; Cárdenas, Hernan

    2006-01-01

    The effects of phenytoin on isolated Pleurodema thaul toad skin were investigated. Low (micromolar) concentrations of the antiepileptic agent applied to the outside surface of the toad epithelium increased the electrical parameters (short-circuit current and potential difference) by over 40%, reflecting stimulation of Na(+) transport, whereas higher (millimolar concentrations, outside and inside surface) decreased both electric parameters, the effect being greater at the inside surface (40% and 80% decrease, respectively). The amiloride test showed that the stimulatory effect was accompanied by an increase and the inhibitory effect by a decrease in the sodium electromotive force (ENa). It is concluded that the drug interaction with membrane lipid bilayers might result in a distortion of the lipid-protein interface contributing to disturbance of Na(+) epithelial channel activity. After applying the Na(+)-K(+)-ATPase blocker ouabain and replacing the Na(+) ions in the outer Ringer's solution by choline, it was concluded that both active and passive transport are involved in sodium absorption, although active transport predominates. PMID:16314149

  18. The role of human carboxylesterases in drug metabolism: have we overlooked their importance?

    PubMed Central

    Laizure, S. Casey; Herring, Vanessa; Hu, Zheyi; Witbrodt, Kevin; Parker, Robert B.

    2012-01-01

    Carboxylesterases are a multi-gene family of enzymes widely distributed throughout the body of mammals that catalyze the hydrolysis of esters, amides, thioesters, and carbamates. In humans, two carboxylesterases, hCE1 and hCE2, are important pathways of drug metabolism. Both are expressed in the liver, but levels of hCE1 greatly exceed those of hCE2. In the intestine only high levels of hCE2 are expressed. The most common drug substrates are ester prodrugs specifically designed to enhance oral bioavailability that must be hydrolyzed to their active carboxylic acid by hydrolysis after absorption from the gastrointestinal tract. However, carboxylesterases also play an important role in the hydrolysis of some drugs to inactive metabolites. It has been widely accepted that drugs undergoing hydrolysis by hCE1 and hCE2 are not subject to clinically significant alterations in their disposition, but there is now a significant and growing body of evidence that genetic polymorphisms, drug-drug interactions, drug-disease interactions and other factors are important determinants of the variability in the therapeutic response to carboxylesterase-substrate drugs. The implications for the safe and effective use of drug therapy is far-reaching, as the patient exposure to substrate drugs includes numerous agents from widely prescribed therapeutic classes such as angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, antiplatelets, HMG-CoA inhibitors, antivirals, and central nervous system agents. PMID:23386599

  19. Drug activity screening based on microsomes-hydrogel system in predicting metabolism induced antitumor effect of oroxylin A

    PubMed Central

    Yang, Huiying; Li, Jianfeng; Zheng, Yuanting; Zhou, Lu; Tong, Shanshan; Zhao, Bei; Cai, Weimin

    2016-01-01

    A novel microsomes-hydrogel added cell culture system (MHCCS) was employed in the antitumor activity screening of natural compounds, aiming to achieve drug screening with better in vivo correlation, higher initiative to explore the potential active metabolites, and investigation of the antitumor mechanism from the perspective of metabolism. MTT assay and cell apoptosis detection showed that test drug oroxylin A (OA) had enhanced cytotoxicity and wogonin (W) with reduced cytotoxicity on MCF-7 cell line upon MHCCS incubation. In vivo antitumor evaluations also demonstrated that OA induced higher tumor inhibition than W at the same dosage. To explore the reasons, nine major metabolites of OA were separated and collected through UPLC-Q-TOF and semi-preparative HPLC. Metabolites M318 exhibited higher cytotoxicity than OA and other metabolites by MTT assay. 1H NMR spectrums, HPLC and TOF MS/MS results revealed that OA was catalyzed into its active metabolite M318 via a ring-opening reaction. M318 induced significant cell apoptosis and S-phase arrest through affecting tumor survival related genes after mechanism study. In conclusion, our MHCCS could be a useful tool for drug activity screening from a perspective of metabolism. PMID:26905263

  20. Insights into drug metabolism by cytochromes P450 from modelling studies of CYP2D6-drug interactions.

    PubMed

    Maréchal, J-D; Kemp, C A; Roberts, G C K; Paine, M J I; Wolf, C R; Sutcliffe, M J

    2008-03-01

    The cytochromes P450 (CYPs) comprise a vast superfamily of enzymes found in virtually all life forms. In mammals, xenobiotic metabolizing CYPs provide crucial protection from the effects of exposure to a wide variety of chemicals, including environmental toxins and therapeutic drugs. Ideally, the information on the possible metabolism by CYPs required during drug development would be obtained from crystal structures of all the CYPs of interest. For some years only crystal structures of distantly related bacterial CYPs were available and homology modelling techniques were used to bridge the gap and produce structural models of human CYPs, and thereby obtain useful functional information. A significant step forward in the reliability of these models came seven years ago with the first crystal structure of a mammalian CYP, rabbit CYP2C5, followed by the structures of six human enzymes, CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2D6 and CYP3A4, and a second rabbit enzyme, CYP2B4. In this review we describe as a case study the evolution of a CYP2D6 model, leading to the validation of the model as an in silico tool for predicting binding and metabolism. This work has led directly to the successful design of CYP2D6 mutants with novel activity-including creating a testosterone hydroxylase, converting quinidine from inhibitor to substrate, creating a diclofenac hydroxylase and creating a dextromethorphan O-demethylase. Our modelling-derived hypothesis-driven integrated interdisciplinary studies have given key insight into the molecular determinants of CYP2D6 and other important drug metabolizing enzymes. PMID:18026129

  1. An overview of on-line systems using drug metabolizing enzymes integrated into capillary electrophoresis.

    PubMed

    Nowak, Paweł; Woźniakiewicz, Michał; Kościelniak, Paweł

    2013-09-01

    Enzymatic assays using CE are now among the most noteworthy applications of this analytical technique in pharmacology-related investigations. Studies of metabolic pathways of new chemical entities mediated by drug metabolizing enzymes are attracting particular attention. Conventional CE-based enzymatic in vitro assays are generally restricted to the separation of reagents after incubation performed off-line. EMMA represents an alternative and fully prospective approach, allowing injection, reaction, separation, and detection to be conducted in a single capillary. Such an on-line system-in contrast to the standard approach-enables automation, miniaturization, and a significant reduction in reagent volumes, resulting in a very robust and cost-efficient method. Hence, EMMA could be a method of choice for the screening of new drugs, enzymatic inhibitors, and putative drug-drug interactions. This review provides a summary of reports covering the area of EMMA-based and related methods implemented into in vitro studies of drug metabolizing enzymes. A general description of the EMMA framework, enzyme families, and a concise discussion of the prognosis for the development of this methodology are given as well.

  2. Interactions between inflammation and lipid metabolism: relevance for efficacy of anti-inflammatory drugs in the treatment of atherosclerosis.

    PubMed

    van Diepen, Janna A; Berbée, Jimmy F P; Havekes, Louis M; Rensen, Patrick C N

    2013-06-01

    Dyslipidemia and inflammation are well known causal risk factors the development of atherosclerosis. The interplay between lipid metabolism and inflammation at multiple levels in metabolic active tissues may exacerbate the development of atherosclerosis, and will be discussed in this review. Cholesterol, fatty acids and modified lipids can directly activate inflammatory pathways. In addition, circulating (modified) lipoproteins modulate the activity of leukocytes. Vice versa, proinflammatory signaling (i.e. cytokines) in pre-clinical models directly affects lipid metabolism. Whereas the main lipid-lowering drugs all have potent anti-inflammatory actions, the lipid-modulating actions of anti-inflammatory agents appear to be less straightforward. The latter have mainly been evaluated in pre-clinical models and in patients with chronic inflammatory diseases, which will be discussed. The clinical trials that are currently conducted to evaluate the efficacy of anti-inflammatory agents in the treatment of cardiovascular diseases may additionally reveal potential (beneficial) effects of these therapeutics on lipid metabolism in the general population at risk for CVD.

  3. Energy metabolism determines the sensitivity of human hepatocellular carcinoma cells to mitochondrial inhibitors and biguanide drugs.

    PubMed

    Hsu, Chia-Chi; Wu, Ling-Chia; Hsia, Cheng-Yuan; Yin, Pen-Hui; Chi, Chin-Wen; Yeh, Tien-Shun; Lee, Hsin-Chen

    2015-09-01

    Human hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide particularly in Asia. Deregulation of cellular energetics was recently included as one of the cancer hallmarks. Compounds that target the mitochondria in cancer cells were proposed to have therapeutic potential. Biguanide drugs which inhibit mitochondrial complex I and repress mTOR signaling are clinically used to treat type 2 diabetes mellitus patients (T2DM) and were recently found to reduce the risk of HCC in T2DM patients. However, whether alteration of energy metabolism is involved in regulating the sensitivity of HCC to biguanide drugs is still unclear. In the present study, we treated four HCC cell lines with mitochondrial inhibitors (rotenone and oligomycin) and biguanide drugs (metformin and phenformin), and found that the HCC cells which had a higher mitochondrial respiration rate were more sensitive to these treatments; whereas the HCC cells which exhibited higher glycolysis were more resistant. When glucose was replaced by galactose in the medium, the altered energy metabolism from glycolysis to mitochondrial respiration in the HCC cells enhanced the cellular sensitivity to mitochondrial inhibitors and biguanides. The energy metabolism change enhanced AMP-activated protein kinase (AMPK) activation, mTOR repression and downregulation of cyclin D1 and Mcl-1 in response to the mitochondrial inhibitors and biguanides. In conclusion, our results suggest that increased mitochondrial oxidative metabolism upregulates the sensitivity of HCC to biguanide drugs. Enhancing the mitochondrial oxidative metabolism in combination with biguanide drugs may be a therapeutic strategy for HCC.

  4. Cardiac metabolic pathways affected in the mouse model of barth syndrome.

    PubMed

    Huang, Yan; Powers, Corey; Madala, Satish K; Greis, Kenneth D; Haffey, Wendy D; Towbin, Jeffrey A; Purevjav, Enkhsaikhan; Javadov, Sabzali; Strauss, Arnold W; Khuchua, Zaza

    2015-01-01

    Cardiolipin (CL) is a mitochondrial phospholipid essential for electron transport chain (ETC) integrity. CL-deficiency in humans is caused by mutations in the tafazzin (Taz) gene and results in a multisystem pediatric disorder, Barth syndrome (BTHS). It has been reported that tafazzin deficiency destabilizes mitochondrial respiratory chain complexes and affects supercomplex assembly. The aim of this study was to investigate the impact of Taz-knockdown on the mitochondrial proteomic landscape and metabolic processes, such as stability of respiratory chain supercomplexes and their interactions with fatty acid oxidation enzymes in cardiac muscle. Proteomic analysis demonstrated reduction of several polypeptides of the mitochondrial respiratory chain, including Rieske and cytochrome c1 subunits of complex III, NADH dehydrogenase alpha subunit 5 of complex I and the catalytic core-forming subunit of F0F1-ATP synthase. Taz gene knockdown resulted in upregulation of enzymes of folate and amino acid metabolic pathways in heart mitochondria, demonstrating that Taz-deficiency causes substantive metabolic remodeling in cardiac muscle. Mitochondrial respiratory chain supercomplexes are destabilized in CL-depleted mitochondria from Taz knockdown hearts resulting in disruption of the interactions between ETC and the fatty acid oxidation enzymes, very long-chain acyl-CoA dehydrogenase and long-chain 3-hydroxyacyl-CoA dehydrogenase, potentially affecting the metabolic channeling of reducing equivalents between these two metabolic pathways. Mitochondria-bound myoglobin was significantly reduced in Taz-knockdown hearts, potentially disrupting intracellular oxygen delivery to the oxidative phosphorylation system. Our results identify the critical pathways affected by the Taz-deficiency in mitochondria and establish a future framework for development of therapeutic options for BTHS.

  5. Cardiac Metabolic Pathways Affected in the Mouse Model of Barth Syndrome

    PubMed Central

    Huang, Yan; Powers, Corey; Madala, Satish K.; Greis, Kenneth D.; Haffey, Wendy D.; Towbin, Jeffrey A.; Purevjav, Enkhsaikhan; Javadov, Sabzali; Strauss, Arnold W.; Khuchua, Zaza

    2015-01-01

    Cardiolipin (CL) is a mitochondrial phospholipid essential for electron transport chain (ETC) integrity. CL-deficiency in humans is caused by mutations in the tafazzin (Taz) gene and results in a multisystem pediatric disorder, Barth syndrome (BTHS). It has been reported that tafazzin deficiency destabilizes mitochondrial respiratory chain complexes and affects supercomplex assembly. The aim of this study was to investigate the impact of Taz-knockdown on the mitochondrial proteomic landscape and metabolic processes, such as stability of respiratory chain supercomplexes and their interactions with fatty acid oxidation enzymes in cardiac muscle. Proteomic analysis demonstrated reduction of several polypeptides of the mitochondrial respiratory chain, including Rieske and cytochrome c1 subunits of complex III, NADH dehydrogenase alpha subunit 5 of complex I and the catalytic core-forming subunit of F0F1-ATP synthase. Taz gene knockdown resulted in upregulation of enzymes of folate and amino acid metabolic pathways in heart mitochondria, demonstrating that Taz-deficiency causes substantive metabolic remodeling in cardiac muscle. Mitochondrial respiratory chain supercomplexes are destabilized in CL-depleted mitochondria from Taz knockdown hearts resulting in disruption of the interactions between ETC and the fatty acid oxidation enzymes, very long-chain acyl-CoA dehydrogenase and long-chain 3-hydroxyacyl-CoA dehydrogenase, potentially affecting the metabolic channeling of reducing equivalents between these two metabolic pathways. Mitochondria-bound myoglobin was significantly reduced in Taz-knockdown hearts, potentially disrupting intracellular oxygen delivery to the oxidative phosphorylation system. Our results identify the critical pathways affected by the Taz-deficiency in mitochondria and establish a future framework for development of therapeutic options for BTHS. PMID:26030409

  6. Bromochloromethane, a Methane Analogue, Affects the Microbiota and Metabolic Profiles of the Rat Gastrointestinal Tract

    PubMed Central

    Yang, Yu-Xiang; Mu, Chun-Long; Luo, Zhen

    2015-01-01

    Bromochloromethane (BCM), an inhibitor of methanogenesis, has been used in animal production. However, little is known about its impact on the intestinal microbiota and metabolic patterns. The present study aimed to investigate the effect of BCM on the colonic bacterial community and metabolism by establishing a Wistar rat model. Twenty male Wistar rats were randomly divided into two groups (control and treated with BCM) and raised for 6 weeks. Bacterial fermentation products in the cecum were determined, and colonic methanogens and sulfate-reducing bacteria (SRB) were quantified. The colonic microbiota was analyzed by pyrosequencing of the 16S rRNA genes, and metabolites were profiled by gas chromatography and mass spectrometry. The results showed that BCM did not affect body weight and feed intake, but it did significantly change the intestinal metabolic profiles. Cecal protein fermentation was enhanced by BCM, as methylamine, putrescine, phenylethylamine, tyramine, and skatole were significantly increased. Colonic fatty acid and carbohydrate concentrations were significantly decreased, indicating the perturbation of lipid and carbohydrate metabolism by BCM. BCM treatment decreased the abundance of methanogen populations, while SRB were increased in the colon. BCM did not affect the total colonic bacterial counts but significantly altered the bacterial community composition by decreasing the abundance of actinobacteria, acidobacteria, and proteobacteria. The results demonstrated that BCM treatment significantly altered the microbiotic and metabolite profiles in the intestines, which may provide further information on the use of BCM in animal production. PMID:26567308

  7. Bromochloromethane, a Methane Analogue, Affects the Microbiota and Metabolic Profiles of the Rat Gastrointestinal Tract.

    PubMed

    Yang, Yu-Xiang; Mu, Chun-Long; Luo, Zhen; Zhu, Wei-Yun

    2016-02-01

    Bromochloromethane (BCM), an inhibitor of methanogenesis, has been used in animal production. However, little is known about its impact on the intestinal microbiota and metabolic patterns. The present study aimed to investigate the effect of BCM on the colonic bacterial community and metabolism by establishing a Wistar rat model. Twenty male Wistar rats were randomly divided into two groups (control and treated with BCM) and raised for 6 weeks. Bacterial fermentation products in the cecum were determined, and colonic methanogens and sulfate-reducing bacteria (SRB) were quantified. The colonic microbiota was analyzed by pyrosequencing of the 16S rRNA genes, and metabolites were profiled by gas chromatography and mass spectrometry. The results showed that BCM did not affect body weight and feed intake, but it did significantly change the intestinal metabolic profiles. Cecal protein fermentation was enhanced by BCM, as methylamine, putrescine, phenylethylamine, tyramine, and skatole were significantly increased. Colonic fatty acid and carbohydrate concentrations were significantly decreased, indicating the perturbation of lipid and carbohydrate metabolism by BCM. BCM treatment decreased the abundance of methanogen populations, while SRB were increased in the colon. BCM did not affect the total colonic bacterial counts but significantly altered the bacterial community composition by decreasing the abundance of actinobacteria, acidobacteria, and proteobacteria. The results demonstrated that BCM treatment significantly altered the microbiotic and metabolite profiles in the intestines, which may provide further information on the use of BCM in animal production. PMID:26567308

  8. Nanosilver particle effects on drug metabolism in vitro.

    PubMed

    Lamb, John G; Hathaway, Laura B; Munger, Mark A; Raucy, Judy L; Franklin, Michael R

    2010-12-01

    Nanosilver particles are present in consumer and health care products. Their effects on human microsomal cytochrome P450 (P450) activities and induction in luciferase reporter-engineered Caco-2 (MDR1.C) and HepG2 (DPX2 and 1A2DRE) cells have been investigated. The LD(50) values were ∼ 4 μg silver/ml for HepG2 and 5 μg/ml for Caco-2 cells. At silver concentrations that showed no decreased cell viability (<1 μg silver/ml), the pregnane X receptor (PXR)-driven 4.5-fold induction response of MDR1.C cells to 50 μM omeprazole was unaffected. In DPX2 cells, the PXR-driven 5.5- and 6.5-fold induction responses to omeprazole and 10 μM rifampicin were attenuated to 4- and 3.5-fold, respectively. Nanosilver particles alone showed no induction. In 1A2DRE cells, the aryl hydrocarbon receptor-driven 5.5-fold induction response to omeprazole was attenuated to 4-fold. In 1A2DRE cells, nanosilver alone elicited slight induction at 1 μg/ml. The inhibition of human P450-selective activities by nanosilver particles in vitro was proportional to the silver/microsomal protein ratio. At a fixed (0.5 mg/ml) protein concentration, P450-selective activities differed in sensitivity (IC(50) value). Coumarin 7-hydroxylation and 7-ethoxy-4-trifluoromethylcoumarin O-deethylation exhibited the highest IC(50) values (33.5 and 31.9 μM, respectively) and S-mephenytoin 4-hydroxylation exhibited the lowest (6.4 μM). Other IC(50) values were, in ascending order, 8.0 to 9.3 μM (testosterone 6β-hydroxylation, 7-benzyloxyquinoline debenzylation, and diclofenac 4-hydroxylation), 16.0 μM (chlorzoxazone 6-hydroxylation), 21.2 μM [7-methoxy-4-(aminomethyl)-coumarin O-demethylation], and 24.4 μM (7-methoxyresorufin O-demethylation). An investigation of 70 μM nanosilver particles showed that microsomal NADPH cytochrome c reductase activities were inhibited <12%. From our in vitro observations, we extrapolated that nanosilver particles reaching the liver may be a potential source of drug-drug

  9. Global Phenotypic Characterization of Effects of Fluoroquinolone Resistance Selection on the Metabolic Activities and Drug Susceptibilities of Clostridium perfringens Strains.

    PubMed

    Park, Miseon; Rafii, Fatemeh

    2014-01-01

    Fluoroquinolone resistance affects toxin production of Clostridium perfringens strains differently. To investigate the effect of fluoroquinolone resistance selection on global changes in metabolic activities and drug susceptibilities, four C. perfringens strains and their norfloxacin-, ciprofloxacin-, and gatifloxacin-resistant mutants were compared in nearly 2000 assays, using phenotype microarray plates. Variations among mutant strains resulting from resistance selection were observed in all aspects of metabolism. Carbon utilization, pH range, osmotic tolerance, and chemical sensitivity of resistant strains were affected differently in the resistant mutants depending on both the bacterial genotype and the fluoroquinolone to which the bacterium was resistant. The susceptibilities to gentamicin and erythromycin of all resistant mutants except one increased, but some resistant strains were less susceptible to amoxicillin, cefoxitin, ceftriaxone, chloramphenicol, and metronidazole than their wild types. Sensitivity to ethidium bromide decreased in some resistant mutants and increased in others. Microarray analysis of two gatifloxacin-resistant mutants showed changes in metabolic activities that were correlated with altered expression of various genes. Both the chemical structures of fluoroquinolones and the genomic makeup of the wild types influenced the changes found in resistant mutants, which may explain some inconsistent reports of the effects of therapeutic use of fluoroquinolones on clinical isolates of bacteria. PMID:25587280

  10. The risk of adverse drug reactions in older patients: beyond drug metabolism.

    PubMed

    Onder, Graziano; Lattanzio, Fabrizia; Battaglia, Miriam; Cerullo, Francesco; Sportiello, Roberta; Bernabei, Roberto; Landi, Francesco

    2011-09-01

    Changes in pharmacokinetics and pharmacodynamics, associated with increasing age, are often considered the only culprits of increasing Adverse Drug Reactions (ADR) rate observed in older adults, but other factors may be responsible for a reduction in drug efficacy and increase the risk of iatrogenic illness in this population. The aging process is characterized by a high level of complexity, which makes the care of older adults and the use of medications a challenging task. In particular, comorbidity, geriatric syndromes, cognitive and functional deficits, limited life expectancy are typical conditions observed in older adults which may reduce the efficacy of prescribed drugs and increase the risk of iatrogenic illness. As a consequence, a comprehensive assessment and management of the health care problems, with the goal of recognizing and preventing potential drug-related problems and improve quality of prescribing is necessary to reduce the risk of ADR. Several studies have assessed the effect of a comprehensive geriatric assessment and management on drug prescribing and drug related illness, showing a substantial improvement in quality of prescription and a reduction in rate of ADR. In addition, clinical guidelines providing recommendations regarding the use of drugs in chronic disease rarely assess the level of complexity observed in older adults and therefore they should be applied with caution in this population. PMID:21495971

  11. [THE ANALYSIS OF INDICATORS OF MINERAL METABOLISM IN PATIENTS WITH DEGENERATIVE DYSTROPHIC AFFECTIONS OF JOINTS].

    PubMed

    Gasanova, A G; Matveeva, E L; Spirkina, E S

    2015-12-01

    The analysis of indicators of mineral metabolism in patients with degenerative dystrophic affections of joints demonstrated that under development of osteoarthrosis process the alteration of indicators of concentration of electrolytes in blood serum, urine and synovial fluid occurs. The stage II of process is characterized by maximal alterations of indicators. The indicator of relationship between concentration of phosphate-ion and index of phosphatases of blood serum turned out the significant coefficient of correlation. PMID:27032248

  12. [THE ANALYSIS OF INDICATORS OF MINERAL METABOLISM IN PATIENTS WITH DEGENERATIVE DYSTROPHIC AFFECTIONS OF JOINTS].

    PubMed

    Gasanova, A G; Matveeva, E L; Spirkina, E S

    2015-12-01

    The analysis of indicators of mineral metabolism in patients with degenerative dystrophic affections of joints demonstrated that under development of osteoarthrosis process the alteration of indicators of concentration of electrolytes in blood serum, urine and synovial fluid occurs. The stage II of process is characterized by maximal alterations of indicators. The indicator of relationship between concentration of phosphate-ion and index of phosphatases of blood serum turned out the significant coefficient of correlation.

  13. Impact of metabolizing enzymes on drug response of endocrine therapy in breast cancer.

    PubMed

    Saladores, Pilar H; Precht, Jana C; Schroth, Werner; Brauch, Hiltrud; Schwab, Matthias

    2013-05-01

    Estrogen-receptor positive breast cancer accounts for 75% of diagnosed breast cancers worldwide. There are currently two major options for adjuvant treatment: tamoxifen and aromatase inhibitors. Variability in metabolizing enzymes determines their pharmacokinetic profile, possibly affecting treatment response. Therefore, prediction of therapy outcome based on genotypes would enable a more personalized medicine approach, providing optimal therapy for each patient. In this review, the authors will discuss the current evidence on the most important metabolizing enzymes in endocrine therapy, with a special focus on CYP2D6 and its role in tamoxifen metabolism.

  14. Metabolism-related pharmacokinetic drug−drug interactions with tyrosine kinase inhibitors: current understanding, challenges and recommendations

    PubMed Central

    Teo, Yi Ling; Ho, Han Kiat; Chan, Alexandre

    2015-01-01

    Drug−drug interactions (DDIs) occur when a patient's response to the drug is modified by administration or co-exposure to another drug. The main cytochrome P450 (CYP) enzyme, CYP3A4, is implicated in the metabolism of almost all of the tyrosine kinase inhibitors (TKIs). Therefore, there is a substantial potential for interaction between TKIs and other drugs that modulate the activity of this metabolic pathway. Cancer patients are susceptible to DDIs as they receive many medications, either for supportive care or for treatment of toxicity. Differences in DDI outcomes are generally negligible because of the wide therapeutic window of common drugs. However for anticancer agents, serious clinical consequences may occur from small changes in drug metabolism and pharmacokinetics. Therefore, the objective of this review is to highlight the current understanding of DDIs among TKIs, with a focus on metabolism, as well as to identify challenges in the prediction of DDIs and provide recommendations. PMID:25125025

  15. Lack of effect of spinal anesthesia on drug metabolism

    SciTech Connect

    Whelan, E.; Wood, A.J.; Shay, S.; Wood, M. )

    1989-09-01

    The effect of spinal anesthesia on drug disposition was determined in six dogs with chronically implanted vascular catheters using propranolol as a model compound. On the first study day, 40 mg of unlabeled propranolol and 200 microCi of (3H)propranolol were injected into the portal and femoral veins respectively. Arterial blood samples were taken for 4 hr for measurement of plasma concentrations of labeled and unlabeled propranolol by high-pressure liquid chromatography (HPLC) and of (3H)propranolol by liquid scintillation counting of the HPLC eluant corresponding to each propranolol peak. Twenty-four hr later, spinal anesthesia was induced with tetracaine (mean dose 20.7 +/- 0.6 mg) with low sacral to midthoracic levels and the propranolol infusions and sampling were then repeated. Spinal anesthesia had no significant effect on either the intrinsic clearance of propranolol (2.01 +/- 0.75 L/min before and 1.9 +/- 0.7 L/min during spinal anesthesia), or on mean hepatic plasma flow (2.01 +/- 0.5 L/min before and 1.93 +/- 0.5 L/min during spinal anesthesia). The systemic clearance and elimination half-life of propranolol were also unchanged by spinal anesthesia (0.9 +/- 0.23 L/min on the first day, 0.7 +/- 0.1 L/min during spinal anesthesia; and 101 +/- 21 min on the first day, 115 +/- 16 min during spinal anesthesia, respectively). The volume of distribution (Vd) of propranolol was similarly unaffected by spinal anesthesia.

  16. Consumption of poisonous plants (Senecio jacobaea, Symphytum officinale, Pteridium aquilinum, Hypericum perforatum) by rats: chronic toxicity, mineral metabolism, and hepatic drug-metabolizing enzymes.

    PubMed

    Garrett, B J; Cheeke, P R; Miranda, C L; Goeger, D E; Buhler, D R

    1982-02-01

    Effect of dietary tancy ragwort (Senecio jacobaea), comfrey (Symphytum officinale), bracken (Pteridium aquilinum) and alfalfa (Medicago sativa) on hepatic drug-metabolizing enzymes in rats were measured. Tansy ragwort and bracken increased (P less than 0.05) the activity of glutathione transferase and epoxide hydrolase. Comfrey and alfalfa increased (P less than 0.05) the activity of aminopyrine N-demethylase. Feeding bracken or St. John's wort (Hypericum perforatum) in conjunction with tansy ragwort did not influence chronic toxicity of tansy ragwort as assessed by rat survival time. Dietary tansy ragwort resulted in increased (P less than 0.05) hepatic copper levels; the other plants did not affect copper levels. The results do not suggest any major interaction in the toxicity of tansy ragwort with bracken or St. John's wort. PMID:7080084

  17. Metabolism of chamaechromone in vitro with human liver microsomes and recombinant human drug-metabolizing enzymes.

    PubMed

    Lou, Yan; Hu, Haihong; Qiu, Yunqing; Zheng, Jinqi; Wang, Linrun; Zhang, Xingguo; Zeng, Su

    2014-04-01

    Chamaechromone is a major component in the dried roots of Stellera chamaejasme with antihepatitis B virus and insecticidal activity. In this study, metabolic profiles of chamaechromone were investigated in human liver microsomes. One monohydroxide and two monoglucuronides of chamaechromone were identified. The enzyme kinetics for both hydroxylation and glucuronidation were fitted to the Michaelis-Menten equation. The hydroxylation of chamaechromone was inhibited by α-naphthoflavone, and predominantly catalyzed by recombinant human cytochrome P450 1A2, whereas the glucuronidation was inhibited by quercetin, 1-naphthol, and fluconazole, and mainly catalyzed by recombinant human UDP-glucuronosyltransferase 1A3, 1A7, 1A9, and 2B7.

  18. Regulatory challenges for new drugs to treat obesity and comorbid metabolic disorders

    PubMed Central

    Heal, David J; Gosden, Jane; Smith, Sharon L

    2009-01-01

    Obesity is a major cause of morbidity and mortality through cardio- and cerebrovascular diseases and cancer. The metabolic consequences of obesity include dyslipidaemia, hypertension, proinflammatory atherogenesis, pre-diabetes and Type 2 diabetes. For a significant proportion of patients, pharmacotherapy to tackle obesity is required as adjunctive support to diet, exercise and lifestyle modification. To this end, the pharmaceutical industry is pursuing many novel drug targets. Although this view is probably not justified, the recent tribulations of rimonabant have created a perception that the regulatory bar for the approval of antiobesity drugs has been raised. Although >5% of placebo-subtracted weight loss maintained over 1 year is the primary efficacy end-point, it is improvements in cardiovascular risk factors that the Food and Drug Administration (FDA) and European Medicines Agency (EMEA) require to grant approval. Safety aspects are also critical in this indication. Many companies are now switching development of their antiobesity drug candidates into other metabolic disorders. Type 2 diabetes is accepted by the industry and FDA, but not EMEA, as the most appropriate alternative. On the other hand, improvements in plasma lipids produced by antiobesity drugs are moderate compared with established therapies, suggesting dyslipidaemia is not a viable development option. Metabolic Syndrome is not accepted by FDA or EMEA as a discrete disease and the agencies will not licence antiobesity drugs for its treatment. The regulatory environment for antiobesity drugs and the spectrum of indications for which they can be approved could change dramatically if positive data for sibutramine emerge from the SCOUT outcome trial. PMID:20002080

  19. Entamoeba thiol-based redox metabolism: A potential target for drug development.

    PubMed

    Jeelani, Ghulam; Nozaki, Tomoyoshi

    2016-01-01

    Amebiasis is an intestinal infection widespread throughout the world caused by the human pathogen Entamoeba histolytica. Metronidazole has been a drug of choice against amebiasis for decades despite its low efficacy against asymptomatic cyst carriers and emergence of resistance in other protozoa with similar anaerobic metabolism. Therefore, identification and characterization of specific targets is urgently needed to design new therapeutics for improved treatment against amebiasis. Toward this goal, thiol-dependent redox metabolism is of particular interest. The thiol-dependent redox metabolism in E. histolytica consists of proteins including peroxiredoxin, rubrerythrin, Fe-superoxide dismutase, flavodiiron proteins, NADPH: flavin oxidoreductase, and amino acids including l-cysteine, S-methyl-l-cysteine, and thioprolines (thiazolidine-4-carboxylic acids). E. histolytica completely lacks glutathione and its metabolism, and l-cysteine is the major intracellular low molecular mass thiol. Moreover, this parasite possesses a functional thioredoxin system consisting of thioredoxin and thioredoxin reductase, which is a ubiquitous oxidoreductase system with antioxidant and redox regulatory roles. In this review, we summarize and highlight the thiol-based redox metabolism and its control mechanisms in E. histolytica, in particular, the features of the system unique to E. histolytica, and its potential use for drug development against amebiasis. PMID:26775086

  20. Electrochemical simulation of cocaine metabolism-a step toward predictive toxicology for drugs of abuse.

    PubMed

    Mietczarek, Przemystaw; Raoof, Hana; Kottinska, Joltanta H; Stefanowicz, Piotr; Szewczuk, Zbigniew; Sudera, Piotr; Silberringb, Jerzy

    2014-01-01

    Knowledge of the metabolic pathways and biotransformation of the most popular drugs, such as cocaine, amphetamine, morphine and others, is crucial for the elucidation of their possible toxicity and mechanism of action in the human body. In vitro studies on metabolism are mainly based on the incubation of drugs with liver celL homogenate and utilizing Living animals. These methods need to be followed by isolation and detection of metabolic products, which makes these techniques time-consuming and technically demanding. We show here that the oxidative metabolism that occurs in the liver cells and is mainly caused by cytochrome P450 can be successfully mimicked with the electrochemical system [EC] connected on-line with electrospray ionization mass spectrometry. Cocaine was chosen as a model drug for these studies and was analyzed with a previously described system under various conditions using the boron-doped diamond working electrode. The results were compared with the number of metabolites generated by a standard procedure based on the reaction with the rat Liver microsomes. Two electrochemical products of cocaine oxidation were created, of which one was a natural metabolite of cocaine in the human body-norcocaine. The EC provides a promising platform for the screening of the addictive drug phase I metabolism. The metabolites can be directly analyzed by mass spectrometry or collected and separated by Liquid chromatog- raphy. No Liver cell homogenate or microsome is necessary to generate these metabolites, which simplifies separation of the mixtures and reduces time and costs of all experiments. PMID:25507324

  1. Absence of cumulus cells during in vitro maturation affects lipid metabolism in bovine oocytes.

    PubMed

    Auclair, Sylvain; Uzbekov, Rustem; Elis, Sébastien; Sanchez, Laura; Kireev, Igor; Lardic, Lionel; Dalbies-Tran, Rozenn; Uzbekova, Svetlana

    2013-03-15

    Cumulus cells (CC) surround the oocyte and are coupled metabolically through regulation of nutrient intake. CC removal before in vitro maturation (IVM) decreases bovine oocyte developmental competence without affecting nuclear meiotic maturation. The objective was to investigate the influence of CC on oocyte cytoplasmic maturation in relation to energy metabolism. IVM with either cumulus-enclosed (CEO) or -denuded (DO) oocytes was performed in serum-free metabolically optimized medium. Transmission electron microscopy revealed different distribution of membrane-bound vesicles and lipid droplets between metaphase II DO and CEO. By Nile Red staining, a significant reduction in total lipid level was evidenced in DO. Global transcriptomic analysis revealed differential expression of genes regulating energy metabolism, transcription, and translation between CEO and DO. By Western blot, fatty acid synthase (FAS) and hormone-sensitive phospholipase (HSL) proteins were detected in oocytes and in CC, indicating a local lipogenesis and lypolysis. FAS protein was significantly less abundant in DO that in CEO and more highly expressed in CC than in the oocytes. On the contrary, HSL protein was more abundant in oocytes than in CC. In addition, active Ser⁵⁶³-phosphorylated HSL was detected in the oocytes only after IVM, and its level was similar in CEO and DO. In conclusion, absence of CC during IVM affected lipid metabolism in the oocyte and led to suboptimal cytoplasmic maturation. Thus, CC may influence the oocyte by orienting the consumption of nutritive storage via regulation of local fatty acid synthesis and lipolysis to provide energy for maturation. PMID:23321473

  2. Dual drug delivery of tamoxifen and quercetin: Regulated metabolism for anticancer treatment with nanosponges.

    PubMed

    Lockhart, Jacob N; Stevens, David M; Beezer, Dain B; Kravitz, Ariel; Harth, Eva

    2015-12-28

    We report the synthesis and encapsulation of polyester nanosponge particles (NPs) co-loaded with tamoxifen (TAM) and quercetin (QT) to investigate the loading, release and in vitro metabolism of a dual drug formulation. The NPs are made in two variations, 4% and 8% crosslinking densities, to evaluate the effects on metabolism and release kinetics. The NP-4% formulation with a particle size of 89.3 ± 14.8 nm was found to have loading percentages of 6.91 ± 0.13% TAM and 7.72 ± 0.15% QT after targeting 10% (w/w) each. The NP-8% formulation with a particle size of 91.5 ± 9.8 nm was found to have loading percentages of 7.26 ± 0.10% TAM and 7.80 ± 0.12% QT. The stability of the formulation was established in simulated gastrointestinal fluids, and the metabolism of TAM was shown to be reduced 2-fold and 3-fold for NP-4%s and NP-8%s, respectively, while QT metabolism was reduced 3 and 4-fold. The implications for improved bioavailability of the NP formulations were supported by cytotoxicity results that showed a similar efficacy to free dual drug formulations and even enhanced anti-cancer effects in the recovery condition. This work demonstrates the suitability of the nanosponges not only as a dual release drug delivery system but also enabling a regulated metabolism through the capacity of a nanonetwork. The variation in crosslinking enables a dual release with tailored release kinetics and suggests improved bioavailability aided by a reduced metabolism. PMID:26344396

  3. Multispecific Drug Transporter Slc22a8 (Oat3) Regulates Multiple Metabolic and Signaling Pathways

    PubMed Central

    Wu, Wei; Jamshidi, Neema; Eraly, Satish A.; Liu, Henry C.; Bush, Kevin T.; Palsson, Bernhard O.

    2013-01-01

    Multispecific drug transporters of the solute carrier and ATP-binding cassette families are highly conserved through evolution, but their true physiologic role remains unclear. Analyses of the organic anion transporter 3 (OAT3; encoded by Slc22a8/Oat3, originally Roct) knockout mouse have confirmed its critical role in the renal handling of common drugs (e.g., antibiotics, antivirals, diuretics) and toxins. Previous targeted metabolomics of the knockout of the closely related Oat1 have demonstrated a central metabolic role, but the same approach with Oat3 failed to reveal a similar set of endogenous substrates. Nevertheless, the Oat3 knockout is the only Oat described so far with a physiologically significant phenotype, suggesting the disturbance of metabolic or signaling pathways. Here we analyzed global gene expression in Oat3 knockout tissue, which implicated OAT3 in phase I and phase II metabolism (drug metabolizing enzymes or DMEs), as well as signaling pathways. Metabolic reconstruction with the recently developed “mouse Recon1” supported the involvement of Oat3 in the aforementioned pathways. Untargeted metabolomics were used to determine whether the predicted metabolic alterations could be confirmed. Many significant changes were observed; several metabolites were tested for direct interaction with mOAT3, whereas others were supported by published data. Oat3 thus appears critical for the handling of phase I (hydroxylation) and phase II (glucuronidation) metabolites. Oat3 also plays a role in bioenergetic pathways (e.g., the tricarboxylic acid cycle), as well as those involving vitamins (e.g., folate), steroids, prostaglandins, gut microbiome products, uremic toxins, cyclic nucleotides, amino acids, glycans, and possibly hyaluronic acid. The data seemingly consistent with the Remote Sensing and Signaling Hypothesis (Ahn and Nigam, 2009; Wu et al., 2011), also suggests that Oat3 is essential for the handling of dietary flavonoids and antioxidants. PMID

  4. Effects of formulation design on niacin therapeutics: mechanism of action, metabolism, and drug delivery.

    PubMed

    Cooper, Dustin L; Murrell, Derek E; Roane, David S; Harirforoosh, Sam

    2015-07-25

    Niacin is a highly effective, lipid regulating drug associated with a number of metabolically induced side effects such as prostaglandin (PG) mediated flushing and hepatic toxicity. In an attempt to reduce the development of these adverse effects, scientists have investigated differing methods of niacin delivery designed to control drug release and alter metabolism. However, despite successful formulation of various orally based capsule and tablet delivery systems, patient adherence to niacin therapy is still compromised by adverse events such as PG-induced flushing. While the primary advantage of orally dosed formulations is ease of use, alternative delivery options such as transdermal delivery or polymeric micro/nanoparticle encapsulation for oral administration have shown promise in niacin reformulation. However, the effectiveness of these alternative delivery options in reducing inimical effects of niacin and maintaining drug efficacy is still largely unknown and requires more in-depth investigation. In this paper, we present an overview of niacin applications, its metabolic pathways, and current drug delivery formulations. Focus is placed on oral immediate, sustained, and extended release niacin delivery as well as combined statin and/or prostaglandin antagonist niacin formulation. We also examine and discuss current findings involving transdermal niacin formulations and polymeric micro/nanoparticle encapsulated niacin delivery.

  5. The role of ABC transporters in drug resistance, metabolism and toxicity.

    PubMed

    Glavinas, Hristos; Krajcsi, Péter; Cserepes, Judit; Sarkadi, Balázs

    2004-01-01

    ATP Binding Cassette (ABC) transporters form a special family of membrane proteins, characterized by homologous ATP-binding, and large, multispanning transmembrane domains. Several members of this family are primary active transporters, which significantly modulate the absorption, metabolism, cellular effectivity and toxicity of pharmacological agents. This review provides a general overview of the human ABC transporters, their expression, localization and basic mechanism of action. Then we shortly deal with the human ABC transporters as targets of therapeutic interventions in medicine, including cancer drug resistance, lipid and other metabolic disorders, and even gene therapy applications. We place a special emphasis on the three major groups of ABC transporters involved in cancer multidrug resistance (MDR). These are the classical P-glycoprotein (MDR1, ABCB1), the multidrug resistance associated proteins (MRPs, in the ABCC subfamily), and the ABCG2 protein, an ABC half-transporter. All these proteins catalyze an ATP-dependent active transport of chemically unrelated compounds, including anticancer drugs. MDR1 (P-glycoprotein) and ABCG2 preferentially extrude large hydrophobic, positively charged molecules, while the members of the MRP family can extrude both hydrophobic uncharged molecules and water-soluble anionic compounds. Based on the physiological expression and role of these transporters, we provide examples for their role in Absorption-Distribution-Metabolism-Excretion (ADME) and toxicology, and describe several basic assays which can be applied for screening drug interactions with ABC transporters in the course of drug research and development.

  6. Drug metabolism and clearance system in tumor cells of patients with multiple myeloma

    PubMed Central

    Hassen, Wafa; Kassambara, Alboukadel; Reme, Thierry; Sahota, Surinder; Seckinger, Anja; Vincent, Laure; Cartron, Guillaume; Moreaux, Jérôme; Hose, Dirk; Klein, Bernard

    2015-01-01

    Resistance to chemotherapy is a major limitation of cancer treatments with several molecular mechanisms involved, in particular altered local drug metabolism and detoxification process. The role of drug metabolism and clearance system has not been satisfactorily investigated in Multiple Myeloma (MM), a malignant plasma cell cancer for which a majority of patients escapes treatment. The expression of 350 genes encoding for uptake carriers, xenobiotic receptors, phase I and II Drug Metabolizing Enzymes (DMEs) and efflux transporters was interrogated in MM cells (MMCs) of newly-diagnosed patients in relation to their event free survival. MMCs of patients with a favourable outcome have an increased expression of genes coding for xenobiotic receptors (RXRα, LXR, CAR and FXR) and accordingly of their gene targets, influx transporters and phase I/II DMEs. On the contrary, MMCs of patients with unfavourable outcome displayed a global down regulation of genes coding for xenobiotic receptors and the downstream detoxification genes but had a high expression of genes coding for ARNT and Nrf2 pathways and ABC transporters. Altogether, these data suggests ARNT and Nrf2 pathways could be involved in MM primary resistance and that targeting RXRα, PXR, LXR and FXR through agonists could open new perspectives to alleviate or reverse MM drug resistance. PMID:25669983

  7. C282Y-HFE Gene Variant Affects Cholesterol Metabolism in Human Neuroblastoma Cells

    PubMed Central

    Ali-Rahmani, Fatima; Huang, Michael A.; Schengrund, C.-L.; Connor, James R.; Lee, Sang Y.

    2014-01-01

    Although disruptions in the maintenance of iron and cholesterol metabolism have been implicated in several cancers, the association between variants in the HFE gene that is associated with cellular iron uptake and cholesterol metabolism has not been studied. The C282Y-HFE variant is a risk factor for different cancers, is known to affect sphingolipid metabolism, and to result in increased cellular iron uptake. The effect of this variant on cholesterol metabolism and its possible relevance to cancer phenotype was investigated using wild type (WT) and C282Y-HFE transfected human neuroblastoma SH-SY5Y cells. Expression of C282Y-HFE in SH-SY5Y cells resulted in a significant increase in total cholesterol as well as increased transcription of a number of genes involved in its metabolism compared to cells expressing WT-HFE. The marked increase in expression of NPC1L1 relative to that of most other genes, was accompanied by a significant increase in expression of NPC1, a protein that functions in cholesterol uptake by cells. Because inhibitors of cholesterol metabolism have been proposed to be beneficial for treating certain cancers, their effect on the viability of C282Y-HFE neuroblastoma cells was ascertained. C282Y-HFE cells were significantly more sensitive than WT-HFE cells to U18666A, an inhibitor of desmosterol Δ24-reductase the enzyme catalyzing the last step in cholesterol biosynthesis. This was not seen for simvastatin, ezetimibe, or a sphingosine kinase inhibitor. These studies indicate that cancers presenting in carriers of the C282Y-HFE allele might be responsive to treatment designed to selectively reduce cholesterol content in their tumor cells. PMID:24533143

  8. Detection of metabolic activation leading to drug-induced phospholipidosis in rat hepatocyte spheroids.

    PubMed

    Takagi, Masashi; Sanoh, Seigo; Santoh, Masataka; Ejiri, Yoko; Kotake, Yaichiro; Ohta, Shigeru

    2016-02-01

    Drug-induced phospholipidosis (PLD) is one of the adverse reactions to treatment with cationic amphiphilic drugs. Recently, simple and reliable evaluation methods for PLD have been reported. However, the predictive power of these methods for in vivo PLD induction is insufficient in some cases. To accurately predict PLD, we focused on drug metabolism and used three-dimensional cultures of hepatocytes known as spheroids. Here we used the fluorescent phospholipid dye N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (NBD-PE) to detect PLD induction. After 48 hr exposure to 20 µM amiodarone and amitriptyline, PLD inducers, NBD-PE fluorescence in the spheroids was significantly higher than that in the control. In contrast, 1 mM acetaminophen, as a negative control, did not increase fluorescence. Furthermore, the combination of NBD-PE fluorescence and LysoTracker Red fluorescence and the accumulation of intrinsic phospholipids reflected PLD induction in spheroids. To evaluate metabolic activation, we assessed PLD induction by loratadine. NBD-PE fluorescence intensity was significantly increased by 50 µM loratadine treatment. However, the fluorescence was markedly decreased by co-treatment with 500 µM 1-aminobenzotriazole, a broad cytochrome P450 inhibitor. The formation of desloratadine, a metabolite of loratadine, was observed in spheroids after treatment with loratadine alone. These results showed that metabolic activation is the key factor in PLD induction by treatment with loratadine. We demonstrated that rat primary hepatocyte spheroid culture is a useful model for evaluating drug-induced PLD induction mediated by metabolic activation of the drug using the fluorescence probe technique. PMID:26763403

  9. Encapsulation of liver microsomes into a thermosensitive hydrogel for characterization of drug metabolism and toxicity.

    PubMed

    Yang, Huiying; Zheng, Yuanting; Zhao, Bei; Shao, Tengfei; Shi, Qingling; Zhou, Ning; Cai, Weimin

    2013-12-01

    This study reported the encapsulation of liver microsomes into a thermosensitive hydrogel to characterize drug metabolism and predict drug effects. Pluronic(®)F-127 (F127) and acrylamide-bisacrylamide (Acr-Bis) were utilized as the two precursors. After chemical crosslinking catalyzed by ammonium persulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TEMED), the resulting Pluronic F127-acrylamide-bisacrylamide (FAB) hydrogel could encapsulate microsomes at 4 °C and facilitate metabolic reactions at 37 °C. The gel morphology at different Acr-Bis concentrations was characterized using field emission scanning electron microscopy (FE-SEM). Higher concentrations of Acr-Bis could lead to higher degrees of cross-linking of the gel. A fluorescent staining assay was subsequently used to demonstrate successful encapsulation of microsomes into the gel as well as the free diffusion process of micromolecular substrates. The thermosensitivity of the FAB gel was studied using swelling ratio and protein release assay to verify its ability to encapsulate microsomes. The metabolic activity of microsomes encapsulated in gels was investigated by detecting the metabolites of FDA-approved substrates, including dextromethorphan, chlorzoxazone and testosterone. Compared with the traditional method of microsomal incubation, the FAB gel maintained 60%-70% of microsome activity. Lastly, the classic anticancer prodrug cyclophosphamide (CTX) was chosen as a model drug for the study of drug metabolism and the prediction of drug effects. When the microsomes encapsulated in the FAB gel were used in the cell culture system, CTX induced a higher level of apoptosis in MCF-7 cells compared with traditional microsomes. PMID:24075480

  10. Bioprinting of Micro-Organ Tissue Analog for Drug Metabolism Study

    NASA Astrophysics Data System (ADS)

    Sun, Wei

    An evolving application of tissue engineering is to develop in vitro 3D cell/tissue models for drug screening and pharmacological study. In order to test in space, these in vitro models are mostly manufactured through micro-fabrication techniques and incorporate living cells with MEMS or microfluidic devices. These cell-integrated microfluidic devices, or referred as microorgans, are effective in furnishing reliable and inexpensive drug metabolism and toxicity studies [1-3]. This paper will present an on-going research collaborated between Drexel University and NASA JSC Radiation Physics Laboratory for applying a direct cell printing technique to freeform fabrication of 3D liver tissue analog in drug metabolism study. The paper will discuss modeling, design, and solid freeform fabrication of micro-fluidic flow patterns and bioprinting of 3D micro-liver chamber that biomimics liver physiological microenvironment for enhanced drug metabolization. Technical details to address bioprinting of 3D liver tissue analog, integration with a microfluidic device, and basic drug metabolism study for NASA's interests will presented. 1. Holtorf H. Leslie J. Chang R, Nam J, Culbertson C, Sun W, Gonda S, "Development of a Three-Dimensional Tissue-on-a-Chip Micro-Organ Device for Pharmacokinetic Analysis", the 47th Annual Meeting of the American Society for Cell Biology, Washington, DC, December 1-5, 2007. 2. Chang, R., Nam, J., Culbertson C., Holtorf, H., Jeevarajan, A., Gonda, S. and Sun, W., "Bio-printing and Modeling of Flow Patterns for Cell Encapsulated 3D Liver Chambers For Pharmacokinetic Study", TERMIS North America 2007 Conference and Exposition, Westin Harbour Castle, Toronto, Canada, June 13-16, 2007. 3.Starly, B., Chang, R., Sun, W., Culbertson, C., Holtorf, H. and Gonda, S., "Bioprinted Tissue-on-chip Application for Pharmacokinetic Studies", Proceedings of World Congress on Tissue Engineering and Regenerative Medicine, Pittsburgh, PA, USA, April 24-27, 2006.

  11. Cell differentiation within a yeast colony: metabolic and regulatory parallels with a tumor-affected organism.

    PubMed

    Cáp, Michal; Stěpánek, Luděk; Harant, Karel; Váchová, Libuše; Palková, Zdena

    2012-05-25

    Nutrient sensing and metabolic reprogramming are crucial for metazoan cell aging and tumor growth. Here, we identify metabolic and regulatory parallels between a layered, multicellular yeast colony and a tumor-affected organism. During development, a yeast colony stratifies into U and L cells occupying the upper and lower colony regions, respectively. U cells activate a unique metabolism controlled by the glutamine-induced TOR pathway, amino acid-sensing systems (SPS and Gcn4p) and signaling from mitochondria with lowered respiration. These systems jointly modulate U cell physiology, which adapts to nutrient limitations and utilize the nutrients released from L cells. Stress-resistant U cells share metabolic pathways and other similar characteristics with tumor cells, including the ability to proliferate. L cells behave similarly to stressed and starving cells, which activate degradative mechanisms to provide nutrients to U cells. Our data suggest a nutrient flow between both cell types, resembling the Cori cycle and glutamine-NH(4)(+) shuttle between tumor and healthy metazoan cells.

  12. Ceramide metabolism is affected by obesity and diabetes in human adipose tissue.

    PubMed

    Błachnio-Zabielska, A U; Pułka, M; Baranowski, M; Nikołajuk, A; Zabielski, P; Górska, M; Górski, J

    2012-02-01

    Ceramide is involved in development of insulin resistance. However, there are no data on ceramide metabolism in human adipose tissue. The aim of our study was to examine sphingolipid metabolism in fat tissue from obese nondiabetic (n = 11), obese diabetic (n = 11), and lean nondiabetic (n = 8) subjects. The content of ceramide (Cer), dihydroceramide (dhCer), sphingosine (SPH), sphinganine (SPA), sphingosine-1-phosphate (S1P; pmol/mg of protein), the expression (mRNA) and activity of key enzymes responsible for Cer metabolism: serine palmitoyltransferase (SPT), neutral and acidic sphingomyelinase (nSMase and aSMase, respectively), and neutral and acidic ceramidase (nCDase and aCDase, respectively) were examined in human adipose tissue. The contents of SPA and Cer were significantly lower whereas the content of dhCer was higher in both obese groups than the respective values in the lean subjects. The expression of examined enzymes was elevated in both obese groups. The SPT and CDases activity increased whereas aSMase activity deceased in both obese groups. We have found correlation between adipose tissue Cer content and plasma adiponectin concentration (r = 0.69, P < 0.001) and negative correlation between total Cer content and HOMA-IR index (homeostasis model of insulin resistance) (r = -0.67, P < 0.001). We have found that both obesity and diabetes affected pathways of sphingolipid metabolism in the adipose tissue.

  13. How could preventive therapy affect the prevalence of drug resistance? Causes and consequences

    PubMed Central

    Kunkel, Amber; Colijn, Caroline; Lipsitch, Marc; Cohen, Ted

    2015-01-01

    Various forms of preventive and prophylactic antimicrobial therapies have been proposed to combat HIV (e.g. pre-exposure prophylaxis), tuberculosis (e.g. isoniazid preventive therapy) and malaria (e.g. intermittent preventive treatment). However, the potential population-level effects of preventative therapy (PT) on the prevalence of drug resistance are not well understood. PT can directly affect the rate at which resistance is acquired among those receiving PT. It can also indirectly affect resistance by altering the rate at which resistance is acquired through treatment for active disease and by modifying the level of competition between transmission of drug-resistant and drug-sensitive pathogens. We propose a general mathematical model to explore the ways in which PT can affect the long-term prevalence of drug resistance. Depending on the relative contributions of these three mechanisms, we find that increasing the level of coverage of PT may result in increases, decreases or non-monotonic changes in the overall prevalence of drug resistance. These results demonstrate the complexity of the relationship between PT and drug resistance in the population. Care should be taken when predicting population-level changes in drug resistance from small pilot studies of PT or estimates based solely on its direct effects. PMID:25918446

  14. How could preventive therapy affect the prevalence of drug resistance? Causes and consequences.

    PubMed

    Kunkel, Amber; Colijn, Caroline; Lipsitch, Marc; Cohen, Ted

    2015-06-01

    Various forms of preventive and prophylactic antimicrobial therapies have been proposed to combat HIV (e.g. pre-exposure prophylaxis), tuberculosis (e.g. isoniazid preventive therapy) and malaria (e.g. intermittent preventive treatment). However, the potential population-level effects of preventative therapy (PT) on the prevalence of drug resistance are not well understood. PT can directly affect the rate at which resistance is acquired among those receiving PT. It can also indirectly affect resistance by altering the rate at which resistance is acquired through treatment for active disease and by modifying the level of competition between transmission of drug-resistant and drug-sensitive pathogens. We propose a general mathematical model to explore the ways in which PT can affect the long-term prevalence of drug resistance. Depending on the relative contributions of these three mechanisms, we find that increasing the level of coverage of PT may result in increases, decreases or non-monotonic changes in the overall prevalence of drug resistance. These results demonstrate the complexity of the relationship between PT and drug resistance in the population. Care should be taken when predicting population-level changes in drug resistance from small pilot studies of PT or estimates based solely on its direct effects.

  15. Epigallocatechin gallate affects glucose metabolism and increases fitness and lifespan in Drosophila melanogaster

    PubMed Central

    Wagner, Anika E.; Piegholdt, Stefanie; Rabe, Doerte; Baenas, Nieves; Schloesser, Anke; Eggersdorfer, Manfred; Stocker, Achim; Rimbach, Gerald

    2015-01-01

    In this study, we tested whether a standardized epigallocatechin-3-gallate (EGCG) rich green tea extract (comprising > 90% EGCG) affects fitness and lifespan as well as parameters of glucose metabolism and energy homeostasis in the fruit fly, Drosophila melanogaster. Following the application of the green tea extract a significant increase in the mean lifespan (+ 3.3 days) and the 50% survival (+ 4.3 days) as well as improved fitness was detected. These effects went along an increased expression of Spargel, the homolog of mammalian PGC1α, which has been reported to affect lifespan in flies. Intriguingly, in flies, treatment with the green tea extract decreased glucose concentrations, which were accompanied by an inhibition of α-amylase and α-glucosidase activity. Computational docking analysis proved the potential of EGCG to dock into the substrate binding pocket of α-amylase and to a greater extent into α-glucosidase. Furthermore, we demonstrate that EGCG downregulates insulin-like peptide 5 and phosphoenolpyruvate carboxykinase, major regulators of glucose metabolism, as well as the Drosophila homolog of leptin, unpaired 2. We propose that a decrease in glucose metabolism in connection with an upregulated expression of Spargel contribute to the better fitness and the extended lifespan in EGCG-treated flies. PMID:26375250

  16. Epigallocatechin gallate affects glucose metabolism and increases fitness and lifespan in Drosophila melanogaster.

    PubMed

    Wagner, Anika E; Piegholdt, Stefanie; Rabe, Doerte; Baenas, Nieves; Schloesser, Anke; Eggersdorfer, Manfred; Stocker, Achim; Rimbach, Gerald

    2015-10-13

    In this study, we tested whether a standardized epigallocatechin-3-gallate (EGCG) rich green tea extract (comprising > 90% EGCG) affects fitness and lifespan as well as parameters of glucose metabolism and energy homeostasis in the fruit fly, Drosophila melanogaster. Following the application of the green tea extract a significant increase in the mean lifespan (+ 3.3 days) and the 50% survival (+ 4.3 days) as well as improved fitness was detected. These effects went along an increased expression of Spargel, the homolog of mammalian PGC1α, which has been reported to affect lifespan in flies. Intriguingly, in flies, treatment with the green tea extract decreased glucose concentrations, which were accompanied by an inhibition of α-amylase and α-glucosidase activity. Computational docking analysis proved the potential of EGCG to dock into the substrate binding pocket of α-amylase and to a greater extent into α-glucosidase. Furthermore, we demonstrate that EGCG downregulates insulin-like peptide 5 and phosphoenolpyruvate carboxykinase, major regulators of glucose metabolism, as well as the Drosophila homolog of leptin, unpaired 2. We propose that a decrease in glucose metabolism in connection with an upregulated expression of Spargel contribute to the better fitness and the extended lifespan in EGCG-treated flies.

  17. Evidence that high pCO2 affects protein metabolism in tropical reef corals.

    PubMed

    Edmunds, Peter J; Wall, Christopher B

    2014-08-01

    Early life stages of the coral Seriatopora caliendrum were used to test the hypothesis that the depression of dark respiration in coral recruits by high pCO2 is caused by perturbed protein metabolism. First, the contribution of protein anabolism to respiratory costs under high pCO2 was evaluated by measuring the aerobic respiration of S. caliendrum recruits with and without the protein synthesis inhibitor emetine following 1 to 4 days at 45 Pa versus 77 Pa pCO2. Second, protein catabolism under high pCO2 was evaluated by measuring the flux of ammonium (NH4 (+)) from juvenile colonies of S. caliendrum incubated in darkness at 47 Pa and 90 Pa pCO2. Two days after settlement, respiration of recruits was affected by an interaction between emetine and pCO2, with emetine reducing respiration 63% at 45 Pa pCO2 and 27% at 77 Pa pCO2. The interaction disappeared 5 days after settlement, when respiration was reduced 27% by emetine under both pCO2 conditions. These findings suggest that protein anabolism accounted for a large proportion of metabolic costs in coral recruits and was affected by high pCO2, with consequences detected in aerobic respiration. Juvenile S. caliendrum showed net uptake of NH4 (+) at 45 Pa pCO2 but net release of NH4 (+) at 90 Pa pCO2, indicating that protein catabolism, NH4 (+) recycling, or both were affected by high pCO2. Together, these results are consistent with the hypothesis that high pCO2 affects protein metabolism in corals.

  18. PPAR modulators and PPAR pan agonists for metabolic diseases: the next generation of drugs targeting peroxisome proliferator-activated receptors?

    PubMed

    Feldman, P L; Lambert, M H; Henke, B R

    2008-01-01

    The Peroxisome Proliferator-Activated Receptors-PPAR alpha, PPAR gamma, and PPAR delta--are members of the nuclear receptor gene family that have emerged as therapeutic targets for the development of drugs to treat human metabolic diseases. The discovery of high affinity, subtype-selective agonists for each of the three PPAR subtypes has allowed elucidation of the pharmacology of these receptors and development of first-generation therapeutic agents for the treatment of diabetes and dyslipidemia. However, despite proven therapeutic benefits of selective PPAR agonists, safety concerns and dose-limiting side effects have been observed, and a number of late-stage development failures have been reported. Scientists have continued to explore ligand-based activation of PPARs in hopes of developing safer and more effective drugs. This review highlights recent efforts on two newer approaches, the simultaneous activation of all three PPAR receptors with a single ligand (PPAR pan agonists) and the selective modulation of a single PPAR receptor in a cell or tissue specific manner (selective PPAR modulator or SPPARM) in order to induce a subset of target genes and affect a restricted number of metabolic pathways. PMID:18537685

  19. Pharmacogenetics and breast cancer endocrine therapy: CYP2D6 as a predictive factor for tamoxifen metabolism and drug response?

    PubMed Central

    Stearns, Vered; Rae, James M.

    2011-01-01

    The identification of genetic polymorphisms that influence the efficacy and safety of therapies for breast cancer may allow future treatments to be individualised based not only on tumour characteristics but also on host genetics. Genetic factors that affect the metabolism, efficacy and safety of tamoxifen, one of the most common drugs used for the treatment and prevention of breast cancer, have received particular attention. Cytochrome P450 2D6 (CYP2D6) is crucial in the metabolism of tamoxifen to its active metabolite endoxifen. Women with genetic variants of CYP2D6 or who take drugs that inhibit the enzyme have low endoxifen plasma concentrations and may show reduced benefits to tamoxifen treatment. CYP2D6 polymorphisms and variants in other candidate genes may also influence secondary benefits and side effects of tamoxifen. Here, we summarise data suggesting that CYP2D6 status may be an important predictor of the benefits of tamoxifen to an individual; in addition, we briefly discuss the role of variants in other candidate genes. Whether CYP2D6 status should be determined prior to initiating tamoxifen therapy is currently under debate and may be appropriate only for select women who are candidates for tamoxifen alone but for whom alternative standard options are available. PMID:19019258

  20. Metabolic, idiosyncratic toxicity of drugs: overview of the hepatic toxicity induced by the anxiolytic, panadiplon.

    PubMed

    Ulrich, R G; Bacon, J A; Brass, E P; Cramer, C T; Petrella, D K; Sun, E L

    2001-05-16

    Preclinical drug safety evaluation studies, typically conducted in two or more animal species, reveal and define dose-dependent toxicities and undesirable effects related to pharmacological mechanism of action. Idiosyncratic toxic responses are often not detected during this phase in development due to their relative rarity in incidence and differences in species sensitivity. This paper reviews and discusses the metabolic idiosyncratic toxicity and species differences observed for the experimental non-benzodiazepine anxiolytic, panadiplon. This compound produced evidence of hepatic toxicity in Phase 1 clinical trial volunteers that was not predicted by rat, dog or monkey preclinical studies. However, subsequent studies in Dutch-belted rabbits revealed a hepatic toxic syndrome consistent with a Reye's Syndrome-like idiosyncratic response. Investigations into the mechanism of toxicity using rabbits and cultured hepatocytes from several species, including human, provided a sketch of the complex pathway required to produce hepatic injury. This pathway includes drug metabolism to a carboxylic acid metabolite (cyclopropane carboxylic acid), inhibition of mitochondrial fatty acid beta-oxidation, and effects on intermediary metabolism including depletion of glycogen and disruption of glucose homeostasis. We also provide evidence suggesting that the carboxylic acid metabolite decreases the availability of liver CoA and carnitine secondary to the formation of unusual acyl derivatives. Hepatic toxicity could be ameliorated by administration of carnitine, and to a lesser extent by pantothenate. These hepatocellular pathway defects, though not directly resulting in cell death, rendered hepatocytes sensitive to secondary stress, which subsequently produced apoptosis and hepatocellular necrosis. Not all rabbits showed evidence of hepatic toxicity, suggesting that individual or species differences in any step along this pathway may account for idiosyncratic responses. These

  1. Metabolic Network Analysis-Based Identification of Antimicrobial Drug Targets in Category A Bioterrorism Agents

    PubMed Central

    Ahn, Yong-Yeol; Lee, Deok-Sun; Burd, Henry; Blank, William; Kapatral, Vinayak

    2014-01-01

    The 2001 anthrax mail attacks in the United States demonstrated the potential threat of bioterrorism, hence driving the need to develop sophisticated treatment and diagnostic protocols to counter biological warfare. Here, by performing flux balance analyses on the fully-annotated metabolic networks of multiple, whole genome-sequenced bacterial strains, we have identified a large number of metabolic enzymes as potential drug targets for each of the three Category A-designated bioterrorism agents including Bacillus anthracis, Francisella tularensis and Yersinia pestis. Nine metabolic enzymes- belonging to the coenzyme A, folate, phosphatidyl-ethanolamine and nucleic acid pathways common to all strains across the three distinct genera were identified as targets. Antimicrobial agents against some of these enzymes are available. Thus, a combination of cross species-specific antibiotics and common antimicrobials against shared targets may represent a useful combinatorial therapeutic approach against all Category A bioterrorism agents. PMID:24454817

  2. Metabolic network analysis-based identification of antimicrobial drug targets in category A bioterrorism agents.

    PubMed

    Ahn, Yong-Yeol; Lee, Deok-Sun; Burd, Henry; Blank, William; Kapatral, Vinayak

    2014-01-01

    The 2001 anthrax mail attacks in the United States demonstrated the potential threat of bioterrorism, hence driving the need to develop sophisticated treatment and diagnostic protocols to counter biological warfare. Here, by performing flux balance analyses on the fully-annotated metabolic networks of multiple, whole genome-sequenced bacterial strains, we have identified a large number of metabolic enzymes as potential drug targets for each of the three Category A-designated bioterrorism agents including Bacillus anthracis, Francisella tularensis and Yersinia pestis. Nine metabolic enzymes- belonging to the coenzyme A, folate, phosphatidyl-ethanolamine and nucleic acid pathways common to all strains across the three distinct genera were identified as targets. Antimicrobial agents against some of these enzymes are available. Thus, a combination of cross species-specific antibiotics and common antimicrobials against shared targets may represent a useful combinatorial therapeutic approach against all Category A bioterrorism agents.

  3. Food chain transport of nanoparticles affects behaviour and fat metabolism in fish.

    PubMed

    Cedervall, Tommy; Hansson, Lars-Anders; Lard, Mercy; Frohm, Birgitta; Linse, Sara

    2012-01-01

    Nano-sized (10(-9)-10(-7) m) particles offer many technical and biomedical advances over the bulk material. The use of nanoparticles in cosmetics, detergents, food and other commercial products is rapidly increasing despite little knowledge of their effect on organism metabolism. We show here that commercially manufactured polystyrene nanoparticles, transported through an aquatic food chain from algae, through zooplankton to fish, affect lipid metabolism and behaviour of the top consumer. At least three independent metabolic parameters differed between control and test fish: the weight loss, the triglycerides∶cholesterol ratio in blood serum, and the distribution of cholesterol between muscle and liver. Moreover, we demonstrate that nanoparticles bind to apolipoprotein A-I in fish serum in-vitro, thereby restraining them from properly utilising their fat reserves if absorbed through ingestion. In addition to the metabolic effects, we show that consumption of nanoparticle-containing zooplankton affects the feeding behaviour of the fish. The time it took the fish to consume 95% of the food presented to them was more than doubled for nanoparticle-exposed compared to control fish. Since many nano-sized products will, through the sewage system, end up in freshwater and marine habitats, our study provides a potential bioassay for testing new nano-sized material before manufacturing. In conclusion, our study shows that from knowledge of the molecular composition of the protein corona around nanoparticles it is possible to make a testable molecular hypothesis and bioassay of the potential biological risks of a defined nanoparticle at the organism and ecosystem level.

  4. Gestational diabetes mellitus epigenetically affects genes predominantly involved in metabolic diseases

    PubMed Central

    Ruchat, Stephanie-May; Houde, Andrée-Anne; Voisin, Grégory; St-Pierre, Julie; Perron, Patrice; Baillargeon, Jean-Patrice; Gaudet, Daniel; Hivert, Marie-France; Brisson, Diane; Bouchard, Luigi

    2013-01-01

    Offspring exposed to gestational diabetes mellitus (GDM) have an increased risk for chronic diseases, and one promising mechanism for fetal metabolic programming is epigenetics. Therefore, we postulated that GDM exposure impacts the offspring’s methylome and used an epigenomic approach to explore this hypothesis. Placenta and cord blood samples were obtained from 44 newborns, including 30 exposed to GDM. Women were recruited at first trimester of pregnancy and followed until delivery. GDM was assessed after a 75-g oral glucose tolerance test at 24–28 weeks of pregnancy. DNA methylation was measured at > 485,000 CpG sites (Infinium HumanMethylation450 BeadChips). Ingenuity Pathway Analysis was conducted to identify metabolic pathways epigenetically affected by GDM. Our results showed that 3,271 and 3,758 genes in placenta and cord blood, respectively, were potentially differentially methylated between samples exposed or not to GDM (p-values down to 1 × 10−06; none reached the genome-wide significance levels), with more than 25% (n = 1,029) being common to both tissues. Mean DNA methylation differences between groups were 5.7 ± 3.2% and 3.4 ± 1.9% for placenta and cord blood, respectively. These genes were likely involved in the metabolic diseases pathway (up to 115 genes (11%), p-values for pathways = 1.9 × 10−13 < p < 4.0 × 10−03; including diabetes mellitus p = 4.3 × 10−11). Among the differentially methylated genes, 326 in placenta and 117 in cord blood were also associated with newborn weight. Our results therefore suggest that GDM has epigenetic effects on genes preferentially involved in the metabolic diseases pathway, with consequences on fetal growth and development, and provide supportive evidence that DNA methylation is involved in fetal metabolic programming. PMID:23975224

  5. Green Tea minimally affects Biomarkers of Inflammation in Obese Subjects with Metabolic Syndrome

    PubMed Central

    Basu, Arpita; Du, Mei; Sanchez, Karah; Leyva, Misti J.; Betts, Nancy M.; Blevins, Steve; Wu, Mingyuan; Aston, Christopher E.; Lyons, Timothy J.

    2010-01-01

    Objective Green tea (Camellia sinensis) has shown to exert cardio-protective benefits in observational studies. The objective of this clinical trial was to assess the effects of green tea on features of metabolic syndrome and inflammation in obese subjects. Methods We conducted a randomized controlled trial in obese subjects with metabolic syndrome. Thirty-five subjects [age (mean±SE) 42.5±1.7 years, BMI 36.1±1.3 kg/m2] completed the 8-week study and were randomly assigned to receive green tea (4 cups/day), green tea extract (2 capsules and 4 cups water/day), or no treatment (4 cups water/day). Both the beverage and extract groups had similar dosing of epigallocatechin-3-gallate (EGCG), the active green tea polyphenol. Fasting blood samples were collected at screening, four, and eight weeks of the study. Results Green tea beverage or extract supplementation did not significantly alter features of metabolic syndrome or biomarkers of inflammation including adiponectin, C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-1β (IL-1β), soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), leptin, or leptin:adiponectin ratio. However, both green tea beverage and extracts significantly reduced plasma serum amyloid alpha (SAA) versus no treatment (p<0.005). Conclusion This study suggests that the daily consumption of green tea beverage or extracts for 8 weeks was well tolerated but did not affect the features of metabolic syndrome. However, green tea significantly reduced plasma SAA, an independent CVD risk factor, in obese subjects with metabolic syndrome. PMID:20605696

  6. Contribution of metabolites to P450 inhibition-based drug-drug interactions: scholarship from the drug metabolism leadership group of the innovation and quality consortium metabolite group.

    PubMed

    Yu, Hongbin; Balani, Suresh K; Chen, Weichao; Cui, Donghui; He, Ling; Humphreys, W Griffith; Mao, Jialin; Lai, W George; Lee, Anthony J; Lim, Heng-Keang; MacLauchlin, Christopher; Prakash, Chandra; Surapaneni, Sekhar; Tse, Susanna; Upthagrove, Alana; Walsky, Robert L; Wen, Bo; Zeng, Zhaopie

    2015-04-01

    Recent European Medicines Agency (final) and US Food and Drug Administration (draft) drug interaction guidances proposed that human circulating metabolites should be investigated in vitro for their drug-drug interaction (DDI) potential if present at ≥ 25% of the parent area under the time-concentration curve (AUC) (US Food and Drug Administration) or ≥ 25% of the parent and ≥ 10% of the total drug-related AUC (European Medicines Agency). To examine the application of these regulatory recommendations, a group of scientists, representing 18 pharmaceutical companies of the Drug Metabolism Leadership Group of the Innovation and Quality Consortium, conducted a scholarship to assess the risk of contributions by metabolites to cytochrome P450 (P450) inhibition-based DDIs. The group assessed the risk of having a metabolite as the sole contributor to DDI based on literature data and analysis of the 137 most frequently prescribed drugs, defined structural alerts associated with P450 inhibition/inactivation by metabolites, and analyzed current approaches to trigger in vitro DDI studies for metabolites. The group concluded that the risk of P450 inhibition caused by a metabolite alone is low. Only metabolites from 5 of 137 drugs were likely the sole contributor to the in vivo P450 inhibition-based DDIs. Two recommendations were provided when assessing the need to conduct in vitro P450 inhibition studies for metabolites: 1) consider structural alerts that suggest P450 inhibition potential, and 2) use multiple approaches (e.g., a metabolite cut-off value of 100% of the parent AUC and the R(met) strategy) to predict P450 inhibition-based DDIs caused by metabolites in the clinic.

  7. Contribution of metabolites to P450 inhibition-based drug-drug interactions: scholarship from the drug metabolism leadership group of the innovation and quality consortium metabolite group.

    PubMed

    Yu, Hongbin; Balani, Suresh K; Chen, Weichao; Cui, Donghui; He, Ling; Humphreys, W Griffith; Mao, Jialin; Lai, W George; Lee, Anthony J; Lim, Heng-Keang; MacLauchlin, Christopher; Prakash, Chandra; Surapaneni, Sekhar; Tse, Susanna; Upthagrove, Alana; Walsky, Robert L; Wen, Bo; Zeng, Zhaopie

    2015-04-01

    Recent European Medicines Agency (final) and US Food and Drug Administration (draft) drug interaction guidances proposed that human circulating metabolites should be investigated in vitro for their drug-drug interaction (DDI) potential if present at ≥ 25% of the parent area under the time-concentration curve (AUC) (US Food and Drug Administration) or ≥ 25% of the parent and ≥ 10% of the total drug-related AUC (European Medicines Agency). To examine the application of these regulatory recommendations, a group of scientists, representing 18 pharmaceutical companies of the Drug Metabolism Leadership Group of the Innovation and Quality Consortium, conducted a scholarship to assess the risk of contributions by metabolites to cytochrome P450 (P450) inhibition-based DDIs. The group assessed the risk of having a metabolite as the sole contributor to DDI based on literature data and analysis of the 137 most frequently prescribed drugs, defined structural alerts associated with P450 inhibition/inactivation by metabolites, and analyzed current approaches to trigger in vitro DDI studies for metabolites. The group concluded that the risk of P450 inhibition caused by a metabolite alone is low. Only metabolites from 5 of 137 drugs were likely the sole contributor to the in vivo P450 inhibition-based DDIs. Two recommendations were provided when assessing the need to conduct in vitro P450 inhibition studies for metabolites: 1) consider structural alerts that suggest P450 inhibition potential, and 2) use multiple approaches (e.g., a metabolite cut-off value of 100% of the parent AUC and the R(met) strategy) to predict P450 inhibition-based DDIs caused by metabolites in the clinic. PMID:25655830

  8. Effect of rifampin, a potent inducer of drug-metabolizing enzymes, on the pharmacokinetics of raltegravir.

    PubMed

    Wenning, Larissa A; Hanley, William D; Brainard, Diana M; Petry, Amelia S; Ghosh, Kalyan; Jin, Bo; Mangin, Eric; Marbury, Thomas C; Berg, Jolene K; Chodakewitz, Jeffrey A; Stone, Julie A; Gottesdiener, Keith M; Wagner, John A; Iwamoto, Marian

    2009-07-01

    Raltegravir is a human immunodeficiency virus type 1 integrase strand transfer inhibitor that is metabolized by glucuronidation via UGT1A1 and may be affected by inducers of UGT1A1, such as rifampin (rifampicin). Two pharmacokinetic studies were performed in healthy subjects: study 1 examined the effect of administration of 600-mg rifampin once daily on the pharmacokinetics of a single dose of 400-mg raltegravir, and study 2 examined the effect of 600-mg rifampin once daily on the pharmacokinetics of 800-mg raltegravir twice daily compared to 400-mg raltegravir twice daily without rifampin. Raltegravir coadministered with rifampin resulted in lower plasma raltegravir concentrations: in study 1, the geometric mean ratios (GMRs) and 90% confidence intervals (90% CIs) for the plasma raltegravir concentration determined 12 h postdose (C(12)), area under the concentration-time curve from 0 h to infinity (AUC(0-infinity)), and maximum concentration of drug in plasma (C(max)) (400-mg raltegravir plus rifampin/400-mg raltegravir) were 0.39 (0.30, 0.51), 0.60 (0.39, 0.91), and 0.62 (0.37, 1.04), respectively. In study 2, the GMRs and 90% CIs for raltegravir C(12), AUC(0-12), and C(max) (800-mg raltegravir plus rifampin/400-mg raltegravir) were 0.47 (0.36, 0.61), 1.27 (0.94, 1.71), and 1.62 (1.12, 2.33), respectively. Doubling the raltegravir dose to 800 mg when coadministered with rifampin therefore compensates for the effect of rifampin on raltegravir exposure (AUC(0-12)) but does not overcome the effect of rifampin on raltegravir trough concentrations (C(12)). Coadministration of rifampin and raltegravir is not contraindicated; however, caution should be used, since raltegravir trough concentrations in the presence of rifampin are likely to be at the lower limit of clinical experience. PMID:19433563

  9. Interplay of metabolism and transport in determining oral drug absorption and gut wall metabolism: a simulation assessment using the "Advanced Dissolution, Absorption, Metabolism (ADAM)" model.

    PubMed

    Darwich, A S; Neuhoff, S; Jamei, M; Rostami-Hodjegan, A

    2010-11-01

    Bioavailability of orally administered drugs can be influenced by a number of factors including release from the formulation, dissolution, stability in the gastrointestinal (GI) environment, permeability through the gut wall and first-pass gut wall and hepatic metabolism. Although there are various enzymes in the gut wall which may contribute to gut first pass metabolism, Cytochrome P450 (CYP) 3A has been shown to play a major role. The efflux transporter P-glycoprotein (P-gp; MDR1/ABCB1) is the most extensively studied drug efflux transporter in the gut and might have a significant role in the regulation of GI absorption. Although not every CYP3A substrate will have a high extent of gut wall first-pass extraction, being a substrate for the enzyme increases the likelihood of a higher first-pass extraction. Similarly, being a P-gp substrate does not necessarily pose a problem with the gut wall absorption however it may reduce bioavailability in some cases (e.g. when drug has low passive permeability). An on-going debate has focused on the issue of the interplay between CYP3A and P-gp such that high affinity to P-gp increases the exposure of drug to CYP3A through repeated cycling via passive diffusion and active efflux, decreasing the fraction of drug that escapes first pass gut metabolism (F(G)). The presence of P-gp in the gut wall and the high affinity of some CYP3A substrates to this transporter are postulated to reduce the potential for saturating the enzymes, thus increasing gut wall first-pass metabolism for compounds which otherwise would have saturated CYP3A. Such inferences are based on assumptions in the modelling of oral drug absorption. These models should be as mechanistic as possible and tractable using available in vitro and in vivo information. We review, through simulation, this subject and examine the interplay between gut wall metabolism and efflux transporters by studying the fraction of dose absorbed into enterocytes (F(a)) and F(G) via

  10. Nutrient-sensitized screening for drugs that shift energy metabolism from mitochondrial respiration to glycolysis.

    PubMed

    Gohil, Vishal M; Sheth, Sunil A; Nilsson, Roland; Wojtovich, Andrew P; Lee, Jeong Hyun; Perocchi, Fabiana; Chen, William; Clish, Clary B; Ayata, Cenk; Brookes, Paul S; Mootha, Vamsi K

    2010-03-01

    Most cells have the inherent capacity to shift their reliance on glycolysis relative to oxidative metabolism, and studies in model systems have shown that targeting such shifts may be useful in treating or preventing a variety of diseases ranging from cancer to ischemic injury. However, we currently have a limited number of mechanistically distinct classes of drugs that alter the relative activities of these two pathways. We screen for such compounds by scoring the ability of >3,500 small molecules to selectively impair growth and viability of human fibroblasts in media containing either galactose or glucose as the sole sugar source. We identify several clinically used drugs never linked to energy metabolism, including the antiemetic meclizine, which attenuates mitochondrial respiration through a mechanism distinct from that of canonical inhibitors. We further show that meclizine pretreatment confers cardioprotection and neuroprotection against ischemia-reperfusion injury in murine models. Nutrient-sensitized screening may provide a useful framework for understanding gene function and drug action within the context of energy metabolism. PMID:20160716

  11. Urinary metabolites to assess in vivo ontogeny of hepatic drug metabolism in early neonatal life.

    PubMed

    Allegaert, K; Verbesselt, R; Rayyan, M; Debeer, A; de Hoon, J

    2007-05-01

    In addition to size-dependent allometric metabolic activity, most isoenzymes display age-dependent isoenzyme-specific ontogeny. We therefore need probe drugs to describe isoenzyme-specific ontogeny to develop more sophisticated, physiologically based models. We illustrate the feasibility and the relevance of in vivo assessment of hepatic metabolism, based on observations on urinary elimination of paracetamol and tramadol metabolites in neonates. On the basis of the observations on tramadol disposition, we were able to document that O-demethylation phenotypic activity developed sooner when compared with N-demethylation. During repeated administration of intravenous paracetamol, it was documented that, in addition to postmenstrual and postnatal age (PNA), repeated administration also contributed to the urinary excretion of glucuronidated paracetamol. In both probe drugs evaluated, age only in part explained the interindividual variability observed. Urine metabolites to assess in vivo metabolism of drugs routinely administered in neonates likely increase both the feasibility and clinical relevance of studies on in vivo isoenzyme-specific ontogeny in neonates. PMID:17609736

  12. HPLC/ICP-MS in combination with "reverse" online isotope dilution in drug metabolism studies.

    PubMed

    Meermann, Björn; Hulstaert, Anne; Laenen, Aline; Van Looveren, Cis; Vliegen, Maarten; Cuyckens, Filip; Vanhaecke, Frank

    2012-03-01

    During the development of a new drug compound, its metabolism needs to be unraveled. For quantification of the metabolites formed, the drug under investigation is traditionally synthesized with a radiolabel ((14)C or (3)H) and the metabolites present in different matrixes (blood, urine, feces) upon drug administration are determined by means of high-performance liquid chromatography (HPLC) coupled to radiodetection. This approach allows for quantification of the metabolites formed and enables a straightforward distinction between exogenous (i.e., drug-related) and endogenous species (as only the radiolabeled species are detected). However, in some cases, the use of a radiolabeled compound in human in vivo studies is not advisible, e.g., for drug compounds or their metabolites showing a long plasma or tissue half-life. In cases where the candidate drug molecule contains an element detectable by means of inductively coupled plasma mass spectrometry (ICP-MS), HPLC/ICP-MS is a promising alternative approach. However, the method lacks specificity when a distinction between drug-related species and endogenous compounds containing the same target element needs to be accomplished. As a result, we have developed an HPLC/ICP-MS-based method combined with "reverse" online isotope dilution ("reverse" online ID) for metabolite quantification. The methodology was evaluated by the analysis of feces samples from rats dosed with a (81)Br-labeled drug compound. The method allows for both (i) valid quantification of the drug metabolites and (ii) distinction among endogenous, exogenous, and "mixed" species, based on their isotopic "fingerprint". A good repeatability (relative standard deviation of 4.2%) and limit of detection (0.35 mg of drug compound L(-1) of feces extract), of the same order of magnitude as those observed for "normal" online ID HPLC/ICP-MS and HPLC/radiodetection, were achieved.

  13. Development of gold-immobilized P450 platform for exploring the effect of oligomer formation on P450-mediated metabolism for in vitro to in vivo drug metabolism predictions

    NASA Astrophysics Data System (ADS)

    Kabulski, Jarod L.

    The cytochrome P450 (P450) enzyme family is responsible for the biotransformation of a wide range of endogenous and xenobiotic compounds, as well as being the major metabolic enzyme in first pass drug metabolism. In vivo drug metabolism for P450 enzymes is predicted using in vitro data obtained from a reconstituted expressed P450 system, but these systems have not always been proven to accurately represent in vivo enzyme kinetics, due to interactions caused by oligomer formation. These in vitro systems use soluble P450 enzymes prone to oligomer formation and studies have shown that increased states of protein aggregation directly affect the P450 enzyme kinetics. We have developed an immobilized enzyme system that isolates the enzyme and can be used to elucidate the effect of P450 aggregation on metabolism kinetics. The long term goal of my research is to develop a tool that will help improve the assessment of pharmaceuticals by better predicting in vivo kinetics in an in vitro system. The central hypothesis of this research is that P450-mediated kinetics measured in vitro is dependent on oligomer formation and that the accurate prediction of in vivo P450-mediated kinetics requires elucidation of the effect of oligomer formation. The rationale is that the development of a P450 bound to a Au platform can be used to control the aggregation of enzymes and bonding to Au may also permit replacement of the natural redox partners with an electrode capable of supplying a constant flow of electrons. This dissertation explains the details of the enzyme attachment, monitoring substrate binding, and metabolism using physiological and electrochemical methods, determination of enzyme kinetics, and the development of an immobilized-P450 enzyme bioreactor. This work provides alternative approaches to studying P450-mediated kinetics, a platform for controlling enzyme aggregation, electrochemically-driven P450 metabolism, and for investigating the effect of protein

  14. Feline drug metabolism and disposition: pharmacokinetic evidence for species differences and molecular mechanisms

    PubMed Central

    2013-01-01

    Synopsis Although it is widely appreciated that cats respond differently to certain drugs when compared with other companion animal species, the causes of these differences are poorly understood. This review critically evaluates published evidence for altered drug effects in cats, focusing on pharmacokinetic differences between cats, dogs and humans, and the molecular mechanisms underlying these differences. Pharmacokinetic studies indicate that acetaminophen, propofol, carprofen, and acetylsalicylic acid (aspirin) are cleared significantly more slowly in cats versus dogs and humans. All of these drugs are metabolized by conjugation. Cats lack the major phenol UDP-glucuronosyltransferase (UGT) enzymes, including UGT1A6 and UGT1A9, that glucuronidate acetaminophen and propofol. Deficient glucuronidation may also explain slower carprofen clearance, although there is no direct evidence for this. However, poor aspirin clearance in cats appears to be mainly a consequence of slower glycine conjugation. Cats are also deficient in several other conjugation enzymes, including N-acetyltransferase (NAT) 2 and thiopurine methyltransferase (TMPT). NAT2 deficiency may be the reason cats are more prone to developing methemoglobinemia rather than hepatotoxicity from acetaminophen. TMPT deficiency may predispose cats to azathioprine toxicity. No evidence was found for slower elimination of drugs cleared by oxidation or unchanged into urine or bile. Piroxicam, an oxidized drug, was cleared much more rapidly in cats than humans and dogs, although the mechanism for this difference is unclear. More work is needed to better understand drug metabolism and disposition differences in cats, thereby enabling more rational prescribing of existing medications, and the development of safer drugs for this species. PMID:23890237

  15. Prenatal exposure to recreational drugs affects global motion perception in preschool children.

    PubMed

    Chakraborty, Arijit; Anstice, Nicola S; Jacobs, Robert J; LaGasse, Linda L; Lester, Barry M; Wouldes, Trecia A; Thompson, Benjamin

    2015-01-01

    Prenatal exposure to recreational drugs impairs motor and cognitive development; however it is currently unknown whether visual brain areas are affected. To address this question, we investigated the effect of prenatal drug exposure on global motion perception, a behavioural measure of processing within the dorsal extrastriate visual cortex that is thought to be particularly vulnerable to abnormal neurodevelopment. Global motion perception was measured in one hundred and forty-five 4.5-year-old children who had been exposed to different combinations of methamphetamine, alcohol, nicotine and marijuana prior to birth and 25 unexposed children. Self-reported drug use by the mothers was verified by meconium analysis. We found that global motion perception was impaired by prenatal exposure to alcohol and improved significantly by exposure to marijuana. Exposure to both drugs prenatally had no effect. Other visual functions such as habitual visual acuity and stereoacuity were not affected by drug exposure. Prenatal exposure to methamphetamine did not influence visual function. Our results demonstrate that prenatal drug exposure can influence a behavioural measure of visual development, but that the effects are dependent on the specific drugs used during pregnancy. PMID:26581958

  16. Prenatal exposure to recreational drugs affects global motion perception in preschool children

    PubMed Central

    Chakraborty, Arijit; Anstice, Nicola S.; Jacobs, Robert J.; LaGasse, Linda L.; Lester, Barry M.; Wouldes, Trecia A.; Thompson, Benjamin

    2015-01-01

    Prenatal exposure to recreational drugs impairs motor and cognitive development; however it is currently unknown whether visual brain areas are affected. To address this question, we investigated the effect of prenatal drug exposure on global motion perception, a behavioural measure of processing within the dorsal extrastriate visual cortex that is thought to be particularly vulnerable to abnormal neurodevelopment. Global motion perception was measured in one hundred and forty-five 4.5-year-old children who had been exposed to different combinations of methamphetamine, alcohol, nicotine and marijuana prior to birth and 25 unexposed children. Self-reported drug use by the mothers was verified by meconium analysis. We found that global motion perception was impaired by prenatal exposure to alcohol and improved significantly by exposure to marijuana. Exposure to both drugs prenatally had no effect. Other visual functions such as habitual visual acuity and stereoacuity were not affected by drug exposure. Prenatal exposure to methamphetamine did not influence visual function. Our results demonstrate that prenatal drug exposure can influence a behavioural measure of visual development, but that the effects are dependent on the specific drugs used during pregnancy. PMID:26581958

  17. Reaction phenotyping: advances in the experimental strategies used to characterize the contribution of drug-metabolizing enzymes.

    PubMed

    Zientek, Michael A; Youdim, Kuresh

    2015-01-01

    During the process of drug discovery, the pharmaceutical industry is faced with numerous challenges. One challenge is the successful prediction of the major routes of human clearance of new medications. For compounds cleared by metabolism, accurate predictions help provide an early risk assessment of their potential to exhibit significant interpatient differences in pharmacokinetics via routes of metabolism catalyzed by functionally polymorphic enzymes and/or clinically significant metabolic drug-drug interactions. This review details the most recent and emerging in vitro strategies used by drug metabolism and pharmacokinetic scientists to better determine rates and routes of metabolic clearance and how to translate these parameters to estimate the amount these routes contribute to overall clearance, commonly referred to as fraction metabolized. The enzymes covered in this review include cytochrome P450s together with other enzymatic pathways whose involvement in metabolic clearance has become increasingly important as efforts to mitigate cytochrome P450 clearance are successful. Advances in the prediction of the fraction metabolized include newly developed methods to differentiate CYP3A4 from the polymorphic enzyme CYP3A5, scaling tools for UDP-glucuronosyltranferase, and estimation of fraction metabolized for substrates of aldehyde oxidase.

  18. Drug metabolism and pharmacogenetics: the British contribution to fields of international significance

    PubMed Central

    Caldwell, John

    2006-01-01

    The branch of pharmacology we now call ‘drug metabolism', the consideration of the enzymes and procesess determining the disposition of drugs in the body, emerged in the 1840s on the continent of Europe, but British science made little or no contribution until the 1920s. From this point on, the development of the field through the 20th century was shaped to a very significant extent by a series of influential British workers, whose contributions were of global significance and who can now be seen as fathers of the subject. Since the 1950s, and gaining pace inexorably from the 1970s, the significance of drug metabolism to human therapeutics has been greatly added to by the emergence of pharmacogenetics, clinically important hereditary variation in response to drugs, which underpins the current emphasis on personalised medicine. This review examines the British contributions to both these fields through the lives of seven key contributors and attempts to place their work both in the context of its time and its lasting influence. PMID:16402125

  19. The effects of microRNA on the absorption, distribution, metabolism and excretion of drugs

    PubMed Central

    He, Y; Chevillet, J R; Liu, G; Kim, T K; Wang, K

    2015-01-01

    The importance of genetic factors (e.g. sequence variation) in the absorption, distribution, metabolism, excretion (ADME) and overall efficacy of therapeutic agents is well established. Our ability to identify, interpret and utilize these factors is the subject of much clinical investigation and therapeutic development. However, drug ADME and efficacy are also heavily influenced by epigenetic factors such as DNA/histone methylation and non-coding RNAs [especially microRNAs (miRNAs)]. Results from studies using tools, such as in silico miRNA target prediction, in vitro functional assays, nucleic acid profiling/sequencing and high-throughput proteomics, are rapidly expanding our knowledge of these factors and their effects on drug metabolism. Although these studies reveal a complex regulation of drug ADME, an increased understanding of the molecular interplay between the genome, epigenome and transcriptome has the potential to provide practically useful strategies to facilitate drug development, optimize therapeutic efficacy, circumvent adverse effects, yield novel diagnostics and ultimately become an integral component of personalized medicine. PMID:25296724

  20. The Impact of the Gut Microbiota on Drug Metabolism and Clinical Outcome

    PubMed Central

    Enright, Elaine F.; Gahan, Cormac G.M.; Joyce, Susan A.; Griffin, Brendan T.

    2016-01-01

    The significance of the gut microbiota as a determinant of drug pharmacokinetics and accordingly therapeutic response is of increasing importance with the advent of modern medicines characterised by low solubility and/or permeability, or modified-release. These physicochemical properties and release kinetics prolong drug residence times within the gastrointestinal tract, wherein biotransformation by commensal microbes can occur. As the evidence base in support of this supplementary metabolic “organ” expands, novel opportunities to engineer the microbiota for clinical benefit have emerged. This review provides an overview of microbe-mediated alteration of drug pharmacokinetics, with particular emphasis on studies demonstrating proof of concept in vivo. Additionally, recent advances in modulating the microbiota to improve clinical response to therapeutics are explored.

  1. The Impact of the Gut Microbiota on Drug Metabolism and Clinical Outcome

    PubMed Central

    Enright, Elaine F.; Gahan, Cormac G.M.; Joyce, Susan A.; Griffin, Brendan T.

    2016-01-01

    The significance of the gut microbiota as a determinant of drug pharmacokinetics and accordingly therapeutic response is of increasing importance with the advent of modern medicines characterised by low solubility and/or permeability, or modified-release. These physicochemical properties and release kinetics prolong drug residence times within the gastrointestinal tract, wherein biotransformation by commensal microbes can occur. As the evidence base in support of this supplementary metabolic “organ” expands, novel opportunities to engineer the microbiota for clinical benefit have emerged. This review provides an overview of microbe-mediated alteration of drug pharmacokinetics, with particular emphasis on studies demonstrating proof of concept in vivo. Additionally, recent advances in modulating the microbiota to improve clinical response to therapeutics are explored. PMID:27698621

  2. L-Carnosine Affects the Growth of Saccharomyces cerevisiae in a Metabolism-Dependent Manner

    PubMed Central

    Cartwright, Stephanie P.; Bill, Roslyn M.; Hipkiss, Alan R.

    2012-01-01

    The dipeptide L-carnosine (β-alanyl-L-histidine) has been described as enigmatic: it inhibits growth of cancer cells but delays senescence in cultured human fibroblasts and extends the lifespan of male fruit flies. In an attempt to understand these observations, the effects of L-carnosine on the model eukaryote, Saccharomyces cerevisiae, were examined on account of its unique metabolic properties; S. cerevisiae can respire aerobically, but like some tumor cells, it can also exhibit a metabolism in which aerobic respiration is down regulated. L-Carnosine exhibited both inhibitory and stimulatory effects on yeast cells, dependent upon the carbon source in the growth medium. When yeast cells were not reliant on oxidative phosphorylation for energy generation (e.g. when grown on a fermentable carbon source such as 2% glucose), 10–30 mM L-carnosine slowed growth rates in a dose-dependent manner and increased cell death by up to 17%. In contrast, in media containing a non-fermentable carbon source in which yeast are dependent on aerobic respiration (e.g. 2% glycerol), L-carnosine did not provoke cell death. This latter observation was confirmed in the respiratory yeast, Pichia pastoris. Moreover, when deletion strains in the yeast nutrient-sensing pathway were treated with L-carnosine, the cells showed resistance to its inhibitory effects. These findings suggest that L-carnosine affects cells in a metabolism-dependent manner and provide a rationale for its effects on different cell types. PMID:22984600

  3. The fungicide triadimefon affects beer flavor and composition by influencing Saccharomyces cerevisiae metabolism.

    PubMed

    Kong, Zhiqiang; Li, Minmin; An, Jingjing; Chen, Jieying; Bao, Yuming; Francis, Frédéric; Dai, Xiaofeng

    2016-01-01

    Despite the fact that beer is produced on a large scale, the effects of pesticide residues on beer have been rarely investigated. In this study, we used micro-brewing settings to determine the effect of triadimefon on the growth of Saccharomyces cerevisiae and beer flavor. The yeast growth in medium was significantly inhibited (45%) at concentrations higher than 5 mg L(-1), reaching 80% and 100% inhibition at 10 mg L(-1) and 50 mg L(-1), respectively. There were significant differences in sensory quality between beer samples fermented with and without triadimefon based on data obtained with an electronic tongue and nose. Such an effect was most likely underlain by changes in yeast fermentation activity, including decreased utilization of maltotriose and most amino acids, reduced production of isobutyl and isoamyl alcohols, and increased ethyl acetate content in the fungicide treated samples. Furthermore, yeast metabolic profiling by phenotype microarray and UPLC/TOF-MS showed that triadimefon caused significant changes in the metabolism of glutathione, phenylalanine and sphingolipids, and in sterol biosynthesis. Thus, triadimefon negatively affects beer sensory qualities by influencing the metabolic activity of S. cerevisiae during fermentation, emphasizing the necessity of stricter control over fungicide residues in brewing by the food industry. PMID:27629523

  4. Cannibalism Affects Core Metabolic Processes in Helicoverpa armigera Larvae—A 2D NMR Metabolomics Study

    PubMed Central

    Vergara, Fredd; Shino, Amiu; Kikuchi, Jun

    2016-01-01

    Cannibalism is known in many insect species, yet its impact on insect metabolism has not been investigated in detail. This study assessed the effects of cannibalism on the metabolism of fourth-instar larvae of the non-predatory insect Helicoverpa armigera (Lepidotera: Noctuidea). Two groups of larvae were analyzed: one group fed with fourth-instar larvae of H. armigera (cannibal), the other group fed with an artificial plant diet. Water-soluble small organic compounds present in the larvae were analyzed using two-dimensional nuclear magnetic resonance (NMR) and principal component analysis (PCA). Cannibalism negatively affected larval growth. PCA of NMR spectra showed that the metabolic profiles of cannibal and herbivore larvae were statistically different with monomeric sugars, fatty acid- and amino acid-related metabolites as the most variable compounds. Quantitation of 1H-13C HSQC (Heteronuclear Single Quantum Coherence) signals revealed that the concentrations of glucose, glucono-1,5-lactone, glycerol phosphate, glutamine, glycine, leucine, isoleucine, lysine, ornithine, proline, threonine and valine were higher in the herbivore larvae. PMID:27598144

  5. L-carnosine affects the growth of Saccharomyces cerevisiae in a metabolism-dependent manner.

    PubMed

    Cartwright, Stephanie P; Bill, Roslyn M; Hipkiss, Alan R

    2012-01-01

    The dipeptide L-carnosine (β-alanyl-L-histidine) has been described as enigmatic: it inhibits growth of cancer cells but delays senescence in cultured human fibroblasts and extends the lifespan of male fruit flies. In an attempt to understand these observations, the effects of L-carnosine on the model eukaryote, Saccharomyces cerevisiae, were examined on account of its unique metabolic properties; S. cerevisiae can respire aerobically, but like some tumor cells, it can also exhibit a metabolism in which aerobic respiration is down regulated. L-Carnosine exhibited both inhibitory and stimulatory effects on yeast cells, dependent upon the carbon source in the growth medium. When yeast cells were not reliant on oxidative phosphorylation for energy generation (e.g. when grown on a fermentable carbon source such as 2% glucose), 10-30 mM L-carnosine slowed growth rates in a dose-dependent manner and increased cell death by up to 17%. In contrast, in media containing a non-fermentable carbon source in which yeast are dependent on aerobic respiration (e.g. 2% glycerol), L-carnosine did not provoke cell death. This latter observation was confirmed in the respiratory yeast, Pichia pastoris. Moreover, when deletion strains in the yeast nutrient-sensing pathway were treated with L-carnosine, the cells showed resistance to its inhibitory effects. These findings suggest that L-carnosine affects cells in a metabolism-dependent manner and provide a rationale for its effects on different cell types.

  6. DEPTOR in POMC neurons affects liver metabolism but is dispensable for the regulation of energy balance

    PubMed Central

    Caron, Alexandre; Labbé, Sébastien M.; Mouchiroud, Mathilde; Huard, Renaud; Richard, Denis

    2016-01-01

    We have recently demonstrated that specific overexpression of DEP-domain containing mTOR-interacting protein (DEPTOR) in the mediobasal hypothalamus (MBH) protects mice against high-fat diet-induced obesity, revealing DEPTOR as a significant contributor to energy balance regulation. On the basis of evidence that DEPTOR is expressed in the proopiomelanocortin (POMC) neurons of the MBH, the present study aimed to investigate whether these neurons mediate the metabolic effects of DEPTOR. Here, we report that specific DEPTOR overexpression in POMC neurons does not recapitulate any of the phenotypes observed when the protein was overexpressed in the MBH. Unlike the previous model, mice overexpressing DEPTOR only in POMC neurons 1) did not show differences in feeding behavior, 2) did not exhibit changes in locomotion activity and oxygen consumption, 3) did not show an improvement in systemic glucose metabolism, and 4) were not resistant to high-fat diet-induced obesity. These results support the idea that other neuronal populations are responsible for these phenotypes. Nonetheless, we observed a mild elevation in fasting blood glucose, insulin resistance, and alterations in liver glucose and lipid homeostasis in mice overexpressing DEPTOR in POMC neurons. Taken together, these results show that DEPTOR overexpression in POMC neurons does not affect energy balance regulation but could modulate metabolism through a brain-liver connection. PMID:27097662

  7. Cannibalism Affects Core Metabolic Processes in Helicoverpa armigera Larvae-A 2D NMR Metabolomics Study.

    PubMed

    Vergara, Fredd; Shino, Amiu; Kikuchi, Jun

    2016-01-01

    Cannibalism is known in many insect species, yet its impact on insect metabolism has not been investigated in detail. This study assessed the effects of cannibalism on the metabolism of fourth-instar larvae of the non-predatory insect Helicoverpa armigera (Lepidotera: Noctuidea). Two groups of larvae were analyzed: one group fed with fourth-instar larvae of H. armigera (cannibal), the other group fed with an artificial plant diet. Water-soluble small organic compounds present in the larvae were analyzed using two-dimensional nuclear magnetic resonance (NMR) and principal component analysis (PCA). Cannibalism negatively affected larval growth. PCA of NMR spectra showed that the metabolic profiles of cannibal and herbivore larvae were statistically different with monomeric sugars, fatty acid- and amino acid-related metabolites as the most variable compounds. Quantitation of ¹H-(13)C HSQC (Heteronuclear Single Quantum Coherence) signals revealed that the concentrations of glucose, glucono-1,5-lactone, glycerol phosphate, glutamine, glycine, leucine, isoleucine, lysine, ornithine, proline, threonine and valine were higher in the herbivore larvae. PMID:27598144

  8. The fungicide triadimefon affects beer flavor and composition by influencing Saccharomyces cerevisiae metabolism

    PubMed Central

    Kong, Zhiqiang; Li, Minmin; An, Jingjing; Chen, Jieying; Bao, Yuming; Francis, Frédéric; Dai, Xiaofeng

    2016-01-01

    Despite the fact that beer is produced on a large scale, the effects of pesticide residues on beer have been rarely investigated. In this study, we used micro-brewing settings to determine the effect of triadimefon on the growth of Saccharomyces cerevisiae and beer flavor. The yeast growth in medium was significantly inhibited (45%) at concentrations higher than 5 mg L−1, reaching 80% and 100% inhibition at 10 mg L−1 and 50 mg L−1, respectively. There were significant differences in sensory quality between beer samples fermented with and without triadimefon based on data obtained with an electronic tongue and nose. Such an effect was most likely underlain by changes in yeast fermentation activity, including decreased utilization of maltotriose and most amino acids, reduced production of isobutyl and isoamyl alcohols, and increased ethyl acetate content in the fungicide treated samples. Furthermore, yeast metabolic profiling by phenotype microarray and UPLC/TOF-MS showed that triadimefon caused significant changes in the metabolism of glutathione, phenylalanine and sphingolipids, and in sterol biosynthesis. Thus, triadimefon negatively affects beer sensory qualities by influencing the metabolic activity of S. cerevisiae during fermentation, emphasizing the necessity of stricter control over fungicide residues in brewing by the food industry. PMID:27629523

  9. The fungicide triadimefon affects beer flavor and composition by influencing Saccharomyces cerevisiae metabolism.

    PubMed

    Kong, Zhiqiang; Li, Minmin; An, Jingjing; Chen, Jieying; Bao, Yuming; Francis, Frédéric; Dai, Xiaofeng

    2016-09-15

    Despite the fact that beer is produced on a large scale, the effects of pesticide residues on beer have been rarely investigated. In this study, we used micro-brewing settings to determine the effect of triadimefon on the growth of Saccharomyces cerevisiae and beer flavor. The yeast growth in medium was significantly inhibited (45%) at concentrations higher than 5 mg L(-1), reaching 80% and 100% inhibition at 10 mg L(-1) and 50 mg L(-1), respectively. There were significant differences in sensory quality between beer samples fermented with and without triadimefon based on data obtained with an electronic tongue and nose. Such an effect was most likely underlain by changes in yeast fermentation activity, including decreased utilization of maltotriose and most amino acids, reduced production of isobutyl and isoamyl alcohols, and increased ethyl acetate content in the fungicide treated samples. Furthermore, yeast metabolic profiling by phenotype microarray and UPLC/TOF-MS showed that triadimefon caused significant changes in the metabolism of glutathione, phenylalanine and sphingolipids, and in sterol biosynthesis. Thus, triadimefon negatively affects beer sensory qualities by influencing the metabolic activity of S. cerevisiae during fermentation, emphasizing the necessity of stricter control over fungicide residues in brewing by the food industry.

  10. Nectar resource limitation affects butterfly flight performance and metabolism differently in intensive and extensive agricultural landscapes.

    PubMed

    Lebeau, Julie; Wesselingh, Renate A; Van Dyck, Hans

    2016-05-11

    Flight is an essential biological ability of many insects, but is energetically costly. Environments under rapid human-induced change are characterized by habitat fragmentation and may impose constraints on the energy income budget of organisms. This may, in turn, affect locomotor performance and willingness to fly. We tested flight performance and metabolic rates in meadow brown butterflies (Maniola jurtina) of two contrasted agricultural landscapes: intensively managed, nectar-poor (IL) versus extensively managed, nectar-rich landscapes (EL). Young female adults were submitted to four nectar treatments (i.e. nectar quality and quantity) in outdoor flight cages. IL individuals had better flight capacities in a flight mill and had lower resting metabolic rates (RMR) than EL individuals, except under the severest treatment. Under this treatment, RMR increased in IL individuals, but decreased in EL individuals; flight performance was maintained by IL individuals, but dropped by a factor 2.5 in EL individuals. IL individuals had more canalized (i.e. less plastic) responses relative to the nectar treatments than EL individuals. Our results show significant intraspecific variation in the locomotor and metabolic response of a butterfly to different energy income regimes relative to the landscape of origin. Ecophysiological studies help to improve our mechanistic understanding of the eco-evolutionary impact of anthropogenic environments on rare and widespread species. PMID:27147100

  11. Nectar resource limitation affects butterfly flight performance and metabolism differently in intensive and extensive agricultural landscapes.

    PubMed

    Lebeau, Julie; Wesselingh, Renate A; Van Dyck, Hans

    2016-05-11

    Flight is an essential biological ability of many insects, but is energetically costly. Environments under rapid human-induced change are characterized by habitat fragmentation and may impose constraints on the energy income budget of organisms. This may, in turn, affect locomotor performance and willingness to fly. We tested flight performance and metabolic rates in meadow brown butterflies (Maniola jurtina) of two contrasted agricultural landscapes: intensively managed, nectar-poor (IL) versus extensively managed, nectar-rich landscapes (EL). Young female adults were submitted to four nectar treatments (i.e. nectar quality and quantity) in outdoor flight cages. IL individuals had better flight capacities in a flight mill and had lower resting metabolic rates (RMR) than EL individuals, except under the severest treatment. Under this treatment, RMR increased in IL individuals, but decreased in EL individuals; flight performance was maintained by IL individuals, but dropped by a factor 2.5 in EL individuals. IL individuals had more canalized (i.e. less plastic) responses relative to the nectar treatments than EL individuals. Our results show significant intraspecific variation in the locomotor and metabolic response of a butterfly to different energy income regimes relative to the landscape of origin. Ecophysiological studies help to improve our mechanistic understanding of the eco-evolutionary impact of anthropogenic environments on rare and widespread species.

  12. Putative drug and vaccine target protein identification using comparative genomic analysis of KEGG annotated metabolic pathways of Mycoplasma hyopneumoniae.

    PubMed

    Damte, Dereje; Suh, Joo-Won; Lee, Seung-Jin; Yohannes, Sileshi Belew; Hossain, Md Akil; Park, Seung-Chun

    2013-07-01

    In the present study, a computational comparative and subtractive genomic/proteomic analysis aimed at the identification of putative therapeutic target and vaccine candidate proteins from Kyoto Encyclopedia of Genes and Genomes (KEGG) annotated metabolic pathways of Mycoplasma hyopneumoniae was performed for drug design and vaccine production pipelines against M.hyopneumoniae. The employed comparative genomic and metabolic pathway analysis with a predefined computational systemic workflow extracted a total of 41 annotated metabolic pathways from KEGG among which five were unique to M. hyopneumoniae. A total of 234 proteins were identified to be involved in these metabolic pathways. Although 125 non homologous and predicted essential proteins were found from the total that could serve as potential drug targets and vaccine candidates, additional prioritizing parameters characterize 21 proteins as vaccine candidate while druggability of each of the identified proteins evaluated by the DrugBank database prioritized 42 proteins suitable for drug targets.

  13. Drug elimination function of rat small intestine: metabolism and intraluminal excretion.

    PubMed

    Yasuhara, M; Kurosaki, Y; Kimura, T; Sezaki, H

    1984-10-15

    The metabolic and excretory function of the small intestine was investigated after oral and intravenous administration of drugs having an aromatic amino group to rats. After administration of drugs into the intestinal loop at the initial concentration of 0.1 mM, significant excretion of their N-acetylated forms into the lumen was observed. The amount of N-acetyl forms excreted in the lumen were 39.3 +/- 3.5, 63.5 +/- 20.9 and 18.0 +/- 13.8% of disappeared drugs from the lumen for p-aminobenzoic acid (PABA), p-aminosalicylic acid and sulfanilic acid, respectively. The excretion of p-acetamidobenzoic acid (Ac-PABA) after the absorption of PABA was reduced by the coadministration with salicylic acid, benzoic acid and 2,4-dinitrophenol. Salicylic acid noncompetitively inhibited the acetylation of PABA by the intestinal N-acetyltransferase. A good correlation was found between the intestinal N-acetyltransferase activities for drugs and the intraluminal excretion of N-acetyl derivatives after intestinal absorption of drugs. These results indicate that a drug having a higher susceptibility to intestinal N-acetyltransferase would undergo a greater excretion into the lumen in its N-acetyl form after intestinal absorption. After intravenous administration of PABA at a dose of 100 mumole/kg, 4.02 +/- 0.51% of dose was excreted in the lumen as Ac-PABA in 30 min. On the other hand, a significantly smaller fraction (2.72 +/- 0.68% of dose) was excreted in the lumen after intravenous injection of 100 mumole/kg of Ac-PABA. The larger excretion of Ac-PABA after administration of PABA indicates the contribution of intestinal metabolism on the transfer of PABA not only after oral, but also after intravenous administration.

  14. Application of a Micropatterned Cocultured Hepatocyte System To Predict Preclinical and Human-Specific Drug Metabolism.

    PubMed

    Ballard, T Eric; Wang, Shuai; Cox, Loretta M; Moen, Mark A; Krzyzewski, Stacy; Ukairo, Okechukwu; Obach, R Scott

    2016-02-01

    Laboratory animal models are the industry standard for preclinical risk assessment of drug candidates. Thus, it is important that these species possess profiles of drug metabolites that are similar to those anticipated in human, since metabolites also could be responsible for biologic activities or unanticipated toxicity. Under most circumstances, preclinical species reflect human in vivo metabolites well; however, there have been several notable exceptions, and understanding and predicting these exceptions with an in vitro system would be very useful. Human micropatterned cocultured (MPCC) hepatocytes have been shown to recapitulate human in vivo qualitative metabolic profiles, but the same demonstration has not been performed yet for laboratory animal species. In this study, we investigated several compounds that are known to produce human-unique metabolites through CYP2C9, UGT1A4, aldehyde oxidase (AO), or N-acetyltransferase that were poorly covered or not detected at all in the selected preclinical species. To perform our investigation we used 24-well MPCC hepatocyte plates having three individual human donors and a single donor each of monkey, dog, and rat to study drug metabolism at four time points per species. Through the use of the multispecies MPCC hepatocyte system, the metabolite profiles of the selected compounds in human donors effectively captured the qualitative in vivo metabolite profile with respect to the human metabolite of interest. Human-unique metabolites that were not detected in vivo in certain preclinical species (normally dog and rat) were also not generated in the corresponding species in vitro, confirming that the MPCC hepatocytes can provide an assessment of preclinical species metabolism. From these results, we conclude that multispecies MPCC hepatocyte plates could be used as an effective in vitro tool for preclinical understanding of species metabolism relative to humans and aid in the choice of appropriate preclinical models.

  15. Oxygen Affects Gut Bacterial Colonization and Metabolic Activities in a Gnotobiotic Cockroach Model

    PubMed Central

    Tegtmeier, Dorothee; Thompson, Claire L.; Schauer, Christine

    2015-01-01

    The gut microbiota of termites and cockroaches represents complex metabolic networks of many diverse microbial populations. The distinct microenvironmental conditions within the gut and possible interactions among the microorganisms make it essential to investigate how far the metabolic properties of pure cultures reflect their activities in their natural environment. We established the cockroach Shelfordella lateralis as a gnotobiotic model and inoculated germfree nymphs with two bacterial strains isolated from the guts of conventional cockroaches. Fluorescence microscopy revealed that both strains specifically colonized the germfree hindgut. In diassociated cockroaches, the facultatively anaerobic strain EbSL (a new species of Enterobacteriaceae) always outnumbered the obligately anaerobic strain FuSL (a close relative of Fusobacterium varium), irrespective of the sequence of inoculation, which showed that precolonization by facultatively anaerobic bacteria does not necessarily favor colonization by obligate anaerobes. Comparison of the fermentation products of the cultures formed in vitro with those accumulated in situ indicated that the gut environment strongly affected the metabolic activities of both strains. The pure cultures formed the typical products of mixed-acid or butyrate fermentation, whereas the guts of gnotobiotic cockroaches accumulated mostly lactate and acetate. Similar shifts toward more-oxidized products were observed when the pure cultures were exposed to oxygen, which corroborated the strong effects of oxygen on the metabolic fluxes previously observed in termite guts. Oxygen microsensor profiles of the guts of germfree, gnotobiotic, and conventional cockroaches indicated that both gut tissue and microbiota contribute to oxygen consumption and suggest that the oxygen status influences the colonization success. PMID:26637604

  16. Dietary carbohydrate and lipid source affect cholesterol metabolism of European sea bass (Dicentrarchus labrax) juveniles.

    PubMed

    Castro, Carolina; Corraze, Geneviève; Pérez-Jiménez, Amalia; Larroquet, Laurence; Cluzeaud, Marianne; Panserat, Stéphane; Oliva-Teles, Aires

    2015-10-28

    Plant feedstuffs (PF) are rich in carbohydrates, which may interact with lipid metabolism. Thus, when considering dietary replacement of fishery by-products with PF, knowledge is needed on how dietary lipid source (LS) and carbohydrates affect lipid metabolism and other metabolic pathways. For that purpose, a 73-d growth trial was performed with European sea bass juveniles (IBW 74 g) fed four diets differing in LS (fish oil (FO) or a blend of vegetable oils (VO)) and carbohydrate content (0 % (CH-) or 20 % (CH+) gelatinised starch). At the end of the trial no differences among diets were observed on growth and feed utilisation. Protein efficiency ratio was, however, higher in the CH+ groups. Muscle and liver fatty acid profiles reflected the dietary LS. Dietary carbohydrate promoted higher plasma cholesterol and phospholipids (PL), whole-body and hepatic (mainly 16 : 0) lipids and increased muscular and hepatic glycogen. Except for PL, which were higher in the FO groups, no major alterations between FO and VO groups were observed on plasma metabolites (glucose, TAG, cholesterol, PL), liver and muscle glycogen, and lipid and cholesterol contents. Activities of glucose-6-phosphate dehydrogenase and malic enzyme - lipogenesis-related enzymes - increased with carbohydrate intake. Hepatic expression of genes involved in cholesterol metabolism was up-regulated with carbohydrate (HMGCR and CYP3A27) and VO (HMGCR and CYP51A1) intake. No dietary regulation of long-chain PUFA biosynthesis at the transcriptional level was observed. Overall, very few interactions between dietary carbohydrates and LS were observed. However, important insights on the direct relation between dietary carbohydrate and the cholesterol biosynthetic pathway in European sea bass were demonstrated.

  17. Dietary carbohydrate and lipid source affect cholesterol metabolism of European sea bass (Dicentrarchus labrax) juveniles.

    PubMed

    Castro, Carolina; Corraze, Geneviève; Pérez-Jiménez, Amalia; Larroquet, Laurence; Cluzeaud, Marianne; Panserat, Stéphane; Oliva-Teles, Aires

    2015-10-28

    Plant feedstuffs (PF) are rich in carbohydrates, which may interact with lipid metabolism. Thus, when considering dietary replacement of fishery by-products with PF, knowledge is needed on how dietary lipid source (LS) and carbohydrates affect lipid metabolism and other metabolic pathways. For that purpose, a 73-d growth trial was performed with European sea bass juveniles (IBW 74 g) fed four diets differing in LS (fish oil (FO) or a blend of vegetable oils (VO)) and carbohydrate content (0 % (CH-) or 20 % (CH+) gelatinised starch). At the end of the trial no differences among diets were observed on growth and feed utilisation. Protein efficiency ratio was, however, higher in the CH+ groups. Muscle and liver fatty acid profiles reflected the dietary LS. Dietary carbohydrate promoted higher plasma cholesterol and phospholipids (PL), whole-body and hepatic (mainly 16 : 0) lipids and increased muscular and hepatic glycogen. Except for PL, which were higher in the FO groups, no major alterations between FO and VO groups were observed on plasma metabolites (glucose, TAG, cholesterol, PL), liver and muscle glycogen, and lipid and cholesterol contents. Activities of glucose-6-phosphate dehydrogenase and malic enzyme - lipogenesis-related enzymes - increased with carbohydrate intake. Hepatic expression of genes involved in cholesterol metabolism was up-regulated with carbohydrate (HMGCR and CYP3A27) and VO (HMGCR and CYP51A1) intake. No dietary regulation of long-chain PUFA biosynthesis at the transcriptional level was observed. Overall, very few interactions between dietary carbohydrates and LS were observed. However, important insights on the direct relation between dietary carbohydrate and the cholesterol biosynthetic pathway in European sea bass were demonstrated. PMID:26306559

  18. Oxygen Affects Gut Bacterial Colonization and Metabolic Activities in a Gnotobiotic Cockroach Model.

    PubMed

    Tegtmeier, Dorothee; Thompson, Claire L; Schauer, Christine; Brune, Andreas

    2016-02-01

    The gut microbiota of termites and cockroaches represents complex metabolic networks of many diverse microbial populations. The distinct microenvironmental conditions within the gut and possible interactions among the microorganisms make it essential to investigate how far the metabolic properties of pure cultures reflect their activities in their natural environment. We established the cockroach Shelfordella lateralis as a gnotobiotic model and inoculated germfree nymphs with two bacterial strains isolated from the guts of conventional cockroaches. Fluorescence microscopy revealed that both strains specifically colonized the germfree hindgut. In diassociated cockroaches, the facultatively anaerobic strain EbSL (a new species of Enterobacteriaceae) always outnumbered the obligately anaerobic strain FuSL (a close relative of Fusobacterium varium), irrespective of the sequence of inoculation, which showed that precolonization by facultatively anaerobic bacteria does not necessarily favor colonization by obligate anaerobes. Comparison of the fermentation products of the cultures formed in vitro with those accumulated in situ indicated that the gut environment strongly affected the metabolic activities of both strains. The pure cultures formed the typical products of mixed-acid or butyrate fermentation, whereas the guts of gnotobiotic cockroaches accumulated mostly lactate and acetate. Similar shifts toward more-oxidized products were observed when the pure cultures were exposed to oxygen, which corroborated the strong effects of oxygen on the metabolic fluxes previously observed in termite guts. Oxygen microsensor profiles of the guts of germfree, gnotobiotic, and conventional cockroaches indicated that both gut tissue and microbiota contribute to oxygen consumption and suggest that the oxygen status influences the colonization success. PMID:26637604

  19. Oxygen Affects Gut Bacterial Colonization and Metabolic Activities in a Gnotobiotic Cockroach Model.

    PubMed

    Tegtmeier, Dorothee; Thompson, Claire L; Schauer, Christine; Brune, Andreas

    2015-12-04

    The gut microbiota of termites and cockroaches represents complex metabolic networks of many diverse microbial populations. The distinct microenvironmental conditions within the gut and possible interactions among the microorganisms make it essential to investigate how far the metabolic properties of pure cultures reflect their activities in their natural environment. We established the cockroach Shelfordella lateralis as a gnotobiotic model and inoculated germfree nymphs with two bacterial strains isolated from the guts of conventional cockroaches. Fluorescence microscopy revealed that both strains specifically colonized the germfree hindgut. In diassociated cockroaches, the facultatively anaerobic strain EbSL (a new species of Enterobacteriaceae) always outnumbered the obligately anaerobic strain FuSL (a close relative of Fusobacterium varium), irrespective of the sequence of inoculation, which showed that precolonization by facultatively anaerobic bacteria does not necessarily favor colonization by obligate anaerobes. Comparison of the fermentation products of the cultures formed in vitro with those accumulated in situ indicated that the gut environment strongly affected the metabolic activities of both strains. The pure cultures formed the typical products of mixed-acid or butyrate fermentation, whereas the guts of gnotobiotic cockroaches accumulated mostly lactate and acetate. Similar shifts toward more-oxidized products were observed when the pure cultures were exposed to oxygen, which corroborated the strong effects of oxygen on the metabolic fluxes previously observed in termite guts. Oxygen microsensor profiles of the guts of germfree, gnotobiotic, and conventional cockroaches indicated that both gut tissue and microbiota contribute to oxygen consumption and suggest that the oxygen status influences the colonization success.

  20. Can N-acetyl-L-cysteine affect zinc metabolism when used as a paracetamol antidote?

    PubMed

    Brumas, V; Hacht, B; Filella, M; Berthon, G

    1992-07-01

    N-Acetyl-L-cysteine (NAC) has long been used in the treatment of chronic lung diseases. Inhalation and oral administration of the drug are both effective in reducing mucus viscosity. In addition, NAC oral therapy allows to restore normal mucoprotein secretion in the long term. Although displaying heavy metal-complexing potential, NAC exerts no detectable influence on the metabolism of essential trace metals when used in the above context (i.e. at doses near 600 mg day-1). However, this may no longer be the case when NAC is used as an oxygen radical scavenger, like in the treatment of paracetamol poisoning. In the latter case, intravenous doses as high as 20 g day-1 are administered, which may induce excessive zinc urinary excretion. In order to allow a better appreciation of the risk of zinc depletion during NAC therapy, the present work addresses the role of this drug towards zinc metabolism at the molecular level. First, formation constants for zinc-NAC complexes have been determined under physiological conditions. Then, computer simulations for blood plasma and gastrointestinal fluid have been run to assess the influence of NAC and its metabolites (e.g. cysteine and glutathione) on zinc excretion and absorption. Blood plasma simulations reveal that NAC can effectively mobilise an important fraction of zinc into urinary excretable complexes as from concentrations of 10(-3) mol dm-3 (which corresponds to a dose of about 800 mg). This effect can still be enhanced by the action of NAC metabolites, among which cysteine is the most powerful zinc sequestering agent. In contrast, simulations relative to gastrointestinal conditions suggest that NAC should tend to increase zinc absorption, regardless of its dose. PMID:1529808

  1. Can N-acetyl-L-cysteine affect zinc metabolism when used as a paracetamol antidote?

    PubMed

    Brumas, V; Hacht, B; Filella, M; Berthon, G

    1992-07-01

    N-Acetyl-L-cysteine (NAC) has long been used in the treatment of chronic lung diseases. Inhalation and oral administration of the drug are both effective in reducing mucus viscosity. In addition, NAC oral therapy allows to restore normal mucoprotein secretion in the long term. Although displaying heavy metal-complexing potential, NAC exerts no detectable influence on the metabolism of essential trace metals when used in the above context (i.e. at doses near 600 mg day-1). However, this may no longer be the case when NAC is used as an oxygen radical scavenger, like in the treatment of paracetamol poisoning. In the latter case, intravenous doses as high as 20 g day-1 are administered, which may induce excessive zinc urinary excretion. In order to allow a better appreciation of the risk of zinc depletion during NAC therapy, the present work addresses the role of this drug towards zinc metabolism at the molecular level. First, formation constants for zinc-NAC complexes have been determined under physiological conditions. Then, computer simulations for blood plasma and gastrointestinal fluid have been run to assess the influence of NAC and its metabolites (e.g. cysteine and glutathione) on zinc excretion and absorption. Blood plasma simulations reveal that NAC can effectively mobilise an important fraction of zinc into urinary excretable complexes as from concentrations of 10(-3) mol dm-3 (which corresponds to a dose of about 800 mg). This effect can still be enhanced by the action of NAC metabolites, among which cysteine is the most powerful zinc sequestering agent. In contrast, simulations relative to gastrointestinal conditions suggest that NAC should tend to increase zinc absorption, regardless of its dose.

  2. Nonsense mutations in the human. beta. -globin gene affect mRNA metabolism

    SciTech Connect

    Baserga, S.J.; Benz, E.J. Jr. )

    1988-04-01

    A number of premature translation termination mutations (nonsense mutations) have been described in the human {alpha}- and {beta}-globin genes. Studies on mRNA isolated from patients with {beta}{sup 0}-thalassemia have shown that for both the {beta}-17 and the {beta}-39 mutations less than normal levels of {beta}-globin mRNA accumulate in peripheral blood cells. (The codon at which the mutation occurs designates the name of the mutation; there are 146 codons in human {beta}-globin mRNA). In vitro studies using the cloned {beta}-39 gene have reproduced this effect in a heterologous transfection system and have suggested that the defect resides in intranuclear metabolism. The authors have asked if this phenomenon of decreased mRNA accumulation is a general property of nonsense mutations and if the effect depends on the location or the type of mutation. Toward this end, they have studied the effect of five nonsense mutations and two missense mutations on the expression of human {beta}-globin mRNA in a heterologous transfection system. In all cases studied, the presence of a translation termination codon correlates with a decrease in the steady-state level of mRNA. The data suggest that the metabolism of a mammalian mRNA is affected by the presence of a mutation that affects translation.

  3. Litter Environment Affects Behavior and Brain Metabolic Activity of Adult Knockout Mice

    PubMed Central

    Crews, David; Rushworth, David; Gonzalez-Lima, Francisco; Ogawa, Sonoko

    2009-01-01

    In mammals, the formative environment for social and anxiety-related behaviors is the family unit; in the case of rodents, this is the litter and the mother-young bond. A deciding factor in this environment is the sex ratio of the litter and, in the case of mice lacking functional copies of gene(s), the ratio of the various genotypes in the litter. Both Sex and Genotype ratios of the litter affect the nature and quality of the individual's behavior later in adulthood, as well as metabolic activity in brain nuclei that underlie these behaviors. Mice were raised in litters reconstituted shortly after to birth to control for sex ratio and genotype ratio (wild type pups versus pups lacking a functional estrogen receptor α). In both males and females, the Sex and Genotype of siblings in the litter affected aggressive behaviors as well as patterns of metabolic activity in limbic nuclei in the social behavior network later in adulthood. Further, this pattern in males varied depending upon the Genotype of their brothers and sisters. Principal Components Analysis revealed two components comprised of several amygdalar and hypothalamic nuclei; the VMH showed strong correlations in both clusters, suggesting its pivotal nature in the organization of two neural networks. PMID:19707539

  4. Correlating Structure and Function of Drug-Metabolizing Enzymes: Progress and Ongoing Challenges

    PubMed Central

    Johnson, Eric F.; Connick, J. Patrick; Reed, James R.; Backes, Wayne L.; Desai, Manoj C.; Xu, Lianhong; Estrada, D. Fernando; Laurence, Jennifer S.

    2014-01-01

    This report summarizes a symposium sponsored by the American Society for Pharmacology and Experimental Therapeutics at Experimental Biology held April 20-24 in Boston, MA. Presentations discussed the status of cytochrome P450 (P450) knowledge, emphasizing advances and challenges in relating structure with function and in applying this information to drug design. First, at least one structure of most major human drug-metabolizing P450 enzymes is known. However, the flexibility of these active sites can limit the predictive value of one structure for other ligands. A second limitation is our coarse-grain understanding of P450 interactions with membranes, other P450 enzymes, NADPH–cytochrome P450 reductase, and cytochrome b5. Recent work has examined differential P450 interactions with reductase in mixed P450 systems and P450:P450 complexes in reconstituted systems and cells, suggesting another level of functional control. In addition, protein nuclear magnetic resonance is a new approach to probe these protein/protein interactions, identifying interacting b5 and P450 surfaces, showing that b5 and reductase binding are mutually exclusive, and demonstrating ligand modulation of CYP17A1/b5 interactions. One desired outcome is the application of such information to control drug metabolism and/or design selective P450 inhibitors. A final presentation highlighted development of a CYP3A4 inhibitor that slows clearance of human immunodeficiency virus drugs otherwise rapidly metabolized by CYP3A4. Although understanding P450 structure/function relationships is an ongoing challenge, translational advances will benefit from continued integration of existing and new biophysical approaches. PMID:24130370

  5. Correlating structure and function of drug-metabolizing enzymes: progress and ongoing challenges.

    PubMed

    Johnson, Eric F; Connick, J Patrick; Reed, James R; Backes, Wayne L; Desai, Manoj C; Xu, Lianhong; Estrada, D Fernando; Laurence, Jennifer S; Scott, Emily E

    2014-01-01

    This report summarizes a symposium sponsored by the American Society for Pharmacology and Experimental Therapeutics at Experimental Biology held April 20-24 in Boston, MA. Presentations discussed the status of cytochrome P450 (P450) knowledge, emphasizing advances and challenges in relating structure with function and in applying this information to drug design. First, at least one structure of most major human drug-metabolizing P450 enzymes is known. However, the flexibility of these active sites can limit the predictive value of one structure for other ligands. A second limitation is our coarse-grain understanding of P450 interactions with membranes, other P450 enzymes, NADPH-cytochrome P450 reductase, and cytochrome b5. Recent work has examined differential P450 interactions with reductase in mixed P450 systems and P450:P450 complexes in reconstituted systems and cells, suggesting another level of functional control. In addition, protein nuclear magnetic resonance is a new approach to probe these protein/protein interactions, identifying interacting b5 and P450 surfaces, showing that b5 and reductase binding are mutually exclusive, and demonstrating ligand modulation of CYP17A1/b5 interactions. One desired outcome is the application of such information to control drug metabolism and/or design selective P450 inhibitors. A final presentation highlighted development of a CYP3A4 inhibitor that slows clearance of human immunodeficiency virus drugs otherwise rapidly metabolized by CYP3A4. Although understanding P450 structure/function relationships is an ongoing challenge, translational advances will benefit from continued integration of existing and new biophysical approaches.

  6. Integrated Metabolomics, Transcriptomics and Proteomics Identifies Metabolic Pathways Affected by Anaplasma phagocytophilum Infection in Tick Cells.

    PubMed

    Villar, Margarita; Ayllón, Nieves; Alberdi, Pilar; Moreno, Andrés; Moreno, María; Tobes, Raquel; Mateos-Hernández, Lourdes; Weisheit, Sabine; Bell-Sakyi, Lesley; de la Fuente, José

    2015-12-01

    Anaplasma phagocytophilum is an emerging zoonotic pathogen that causes human granulocytic anaplasmosis. These intracellular bacteria establish infection by affecting cell function in both the vertebrate host and the tick vector, Ixodes scapularis. Previous studies have characterized the tick transcriptome and proteome in response to A. phagocytophilum infection. However, in the postgenomic era, the integration of omics datasets through a systems biology approach allows network-based analyses to describe the complexity and functionality of biological systems such as host-pathogen interactions and the discovery of new targets for prevention and control of infectious diseases. This study reports the first systems biology integration of metabolomics, transcriptomics, and proteomics data to characterize essential metabolic pathways involved in the tick response to A. phagocytophilum infection. The ISE6 tick cells used in this study constitute a model for hemocytes involved in pathogen infection and immune response. The results showed that infection affected protein processing in endoplasmic reticulum and glucose metabolic pathways in tick cells. These results supported tick-Anaplasma co-evolution by providing new evidence of how tick cells limit pathogen infection, while the pathogen benefits from the tick cell response to establish infection. Additionally, ticks benefit from A. phagocytophilum infection by increasing survival while pathogens guarantee transmission. The results suggested that A. phagocytophilum induces protein misfolding to limit the tick cell response and facilitate infection but requires protein degradation to prevent ER stress and cell apoptosis to survive in infected cells. Additionally, A. phagocytophilum may benefit from the tick cell's ability to limit bacterial infection through PEPCK inhibition leading to decreased glucose metabolism, which also results in the inhibition of cell apoptosis that increases infection of tick cells. These results

  7. Model of complex chiral drug metabolic systems and numerical simulation of the remaining chirality toward analysis of dynamical pharmacological activity.

    PubMed

    Ogino, Yoshiyuki; Asahi, Toru

    2015-05-21

    In this study, systems of complicated pathways involved in chiral drug metabolism were investigated. The development of chiral drugs resulted in significant improvement in the remedies available for the treatment of various severe sicknesses. Enantiopure drugs undergo various biological transformations that involve chiral inversion and thus result in the generation of multiple enantiomeric metabolites. Identification of the specific active substances determining a given drug׳s efficacy among such a mixture of different metabolites remains a challenge. To comprehend this complexity, we constructed a mathematical model representing the complicated metabolic pathways simultaneously involving chiral inversion. Moreover, this model is applied to the metabolism of thalidomide, which has recently been revived as a potentially effective prescription drug for a number of intractable diseases. The numerical simulation results indicate that retained chirality in the metabolites reflects the original chirality of the unmetabolized drug, and a higher level of enantiomeric purity is preserved during spontaneous degradation. In addition, chirality remaining after equilibration is directly related to the rate constant not only for chiral inversion but also for generation and degradation. Furthermore, the retention of chirality is quantitatively predictable using this combination of kinetic parameters. Our simulation results well explain the behavior of thalidomide in the practical biological experimental data. Therefore, this model promises a comprehensive understanding of dynamic metabolic systems involving chiral drugs that express multiple enantiospecific drug efficacies.

  8. Model of complex chiral drug metabolic systems and numerical simulation of the remaining chirality toward analysis of dynamical pharmacological activity.

    PubMed

    Ogino, Yoshiyuki; Asahi, Toru

    2015-05-21

    In this study, systems of complicated pathways involved in chiral drug metabolism were investigated. The development of chiral drugs resulted in significant improvement in the remedies available for the treatment of various severe sicknesses. Enantiopure drugs undergo various biological transformations that involve chiral inversion and thus result in the generation of multiple enantiomeric metabolites. Identification of the specific active substances determining a given drug׳s efficacy among such a mixture of different metabolites remains a challenge. To comprehend this complexity, we constructed a mathematical model representing the complicated metabolic pathways simultaneously involving chiral inversion. Moreover, this model is applied to the metabolism of thalidomide, which has recently been revived as a potentially effective prescription drug for a number of intractable diseases. The numerical simulation results indicate that retained chirality in the metabolites reflects the original chirality of the unmetabolized drug, and a higher level of enantiomeric purity is preserved during spontaneous degradation. In addition, chirality remaining after equilibration is directly related to the rate constant not only for chiral inversion but also for generation and degradation. Furthermore, the retention of chirality is quantitatively predictable using this combination of kinetic parameters. Our simulation results well explain the behavior of thalidomide in the practical biological experimental data. Therefore, this model promises a comprehensive understanding of dynamic metabolic systems involving chiral drugs that express multiple enantiospecific drug efficacies. PMID:25791284

  9. Drug Issues Affecting Chinese, Indian and Pakistani People Living in Greater Glasgow

    ERIC Educational Resources Information Center

    Ross, A. J.; Heim, D.; Bakshi, N.; Davies, J. B.; Flatley, K. J.; Hunter, S. C.

    2004-01-01

    This paper describes research on drug issues affecting Chinese, Indian and Pakistani people living in Greater Glasgow. There were two strands: (i) a questionnaire-based survey of young people and focus groups; (ii) interviews with young people and adults. The primary aims were to gather prevalence data and to investigate perceptions about current…

  10. Resources Related to Children and Their Families Affected by Alcohol and Other Drugs. 3rd Edition.

    ERIC Educational Resources Information Center

    Melner, Joan; Shackelford, Jo; Hargrove, Elisabeth; Daulton, Deb

    This document identifies resources that serve young children and their families affected by alcohol and other drug use. The resources are organized into three sections: National Training and Information Resources, State Programs and Agencies, and Federal Funding Sources. Information on locating grant funds from federal agencies, private…

  11. Mechanisms Underlying Food-Drug Interactions: Inhibition of Intestinal Metabolism and Transport

    PubMed Central

    Won, Christina S.; Oberlies, Nicholas H.; Paine, Mary F.

    2012-01-01

    Food-drug interaction studies are critical to evaluate appropriate dosing, timing, and formulation of new drug candidates. These interactions often reflect prandial-associated changes in the extent and/or rate of systemic drug exposure. Physiologic and physicochemical mechanisms underlying food effects on drug disposition are well-characterized. However, biochemical mechanisms involving drug metabolizing enzymes and transport proteins remain underexplored. Several plant-derived beverages have been shown to modulate enzymes and transporters in the intestine, leading to altered pharmacokinetic (PK) and potentially negative pharmacodynamic (PD) outcomes. Commonly consumed fruit juices, teas, and alcoholic drinks contain phytochemicals that inhibit intestinal cytochrome P450 and phase II conjugation enzymes, as well as uptake and efflux transport proteins. Whereas myriad phytochemicals have been shown to inhibit these processes in vitro, translation to the clinic has been deemed insignificant or undetermined. An overlooked prerequisite for elucidating food effects on drug PK is thorough knowledge of causative bioactive ingredients. Substantial variability in bioactive ingredient composition and activity of a given dietary substance poses a challenge in conducting robust food-drug interaction studies. This confounding factor can be addressed by identifying and characterizing specific components, which could be used as marker compounds to improve clinical trial design and quantitatively predict food effects. Interpretation and integration of data from in vitro, in vivo, and in silico studies require collaborative expertise from multiple disciplines, from botany to clinical pharmacology (i.e., plant to patient). Development of more systematic methods and guidelines is needed to address the general lack of information on examining drug-dietary substance interactions prospectively. PMID:22884524

  12. Metabolism and toxicologic analysis of tryptamine-derived drugs of abuse.

    PubMed

    Katagi, Munehiro; Kamata, Tooru; Zaitsu, Kei; Shima, Noriaki; Kamata, Hiroe; Nakanishi, Keiko; Nishioka, Hiroshi; Miki, Akihiro; Tsuchihashi, Hitoshi

    2010-06-01

    5-Methoxy-N,N-dialkyltryptamines are tryptamine derivatives that possess strong hallucinogenic effects. Because of their escalating popularity and potent physiological effects, an increasing number of acute poisoning cases have been reported in various countries. For their metabolism in humans, only a few studies have been reported. Thus, based on previous studies, the authors forecasted and synthesized authentic standards of their expected metabolites, which retained the structural characteristics of the parent drugs. Using these authentic standards, several urine specimens from abusers and rats were analyzed by gas chromatography mass spectrometry, high-performance liquid chromatography mass spectrometry, and high-performance liquid chromatography tandem mass spectrometry. The present study reveals that four metabolic pathways of great quantitative significance for 5-Methoxy-N,N-dialkyltryptamines to four characteristic metabolites, which retain structural characteristics identifiable with the parent compound, exist in humans and rats. The finding in the present study will be of great importance in the study on the metabolism of other psychotomimetic tryptamine-derived drugs of abuse and in forensic toxicologic analyses.

  13. Defective Cytochrome P450-Catalysed Drug Metabolism in Niemann-Pick Type C Disease.

    PubMed

    Nicoli, Elena-Raluca; Al Eisa, Nada; Cluzeau, Celine V M; Wassif, Christopher A; Gray, James; Burkert, Kathryn R; Smith, David A; Morris, Lauren; Cologna, Stephanie M; Peer, Cody J; Sissung, Tristan M; Uscatu, Constantin-Daniel; Figg, William D; Pavan, William J; Vite, Charles H; Porter, Forbes D; Platt, Frances M

    2016-01-01

    Niemann-Pick type C (NPC) disease is a neurodegenerative lysosomal storage disease caused by mutations in either the NPC1 or NPC2 gene. NPC is characterised by storage of multiple lipids in the late endosomal/lysosomal compartment, resulting in cellular and organ system dysfunction. The underlying molecular mechanisms that lead to the range of clinical presentations in NPC are not fully understood. While evaluating potential small molecule therapies in Npc1-/- mice, we observed a consistent pattern of toxicity associated with drugs metabolised by the cytochrome P450 system, suggesting a potential drug metabolism defect in NPC1 disease. Investigation of the P450 system in the context of NPC1 dysfunction revealed significant changes in the gene expression of many P450 associated genes across the full lifespan of Npc1-/- mice, decreased activity of cytochrome P450 reductase, and a global decrease of multiple cytochrome P450 catalysed dealkylation reactions. In vivo drug metabolism studies using a prototypic P450 metabolised drug, midazolam, confirmed dysfunction in drug clearance in the Npc1-/- mouse. Expression of the Phase II enzyme uridinediphosphate-glucuronosyltransferase (UGT) was also significantly reduced in Npc1-/- mice. Interestingly, reduced activity within the P450 system was also observed in heterozygous Npc1+/- mice. The reduced activity of P450 enzymes may be the result of bile acid deficiency/imbalance in Npc1-/- mice, as bile acid treatment significantly rescued P450 enzyme activity in Npc1-/- mice and has the potential to be an adjunctive therapy for NPC disease patients. The dysfunction in the cytochrome P450 system were recapitulated in the NPC1 feline model. Additionally, we present the first evidence that there are alterations in the P450 system in NPC1 patients. PMID:27019000

  14. Defective Cytochrome P450-Catalysed Drug Metabolism in Niemann-Pick Type C Disease

    PubMed Central

    Wassif, Christopher A.; Gray, James; Burkert, Kathryn R.; Smith, David A.; Morris, Lauren; Cologna, Stephanie M.; Peer, Cody J.; Sissung, Tristan M.; Uscatu, Constantin-Daniel; Figg, William D.; Pavan, William J.; Vite, Charles H.; Porter, Forbes D.; Platt, Frances M.

    2016-01-01

    Niemann-Pick type C (NPC) disease is a neurodegenerative lysosomal storage disease caused by mutations in either the NPC1 or NPC2 gene. NPC is characterised by storage of multiple lipids in the late endosomal/lysosomal compartment, resulting in cellular and organ system dysfunction. The underlying molecular mechanisms that lead to the range of clinical presentations in NPC are not fully understood. While evaluating potential small molecule therapies in Npc1-/- mice, we observed a consistent pattern of toxicity associated with drugs metabolised by the cytochrome P450 system, suggesting a potential drug metabolism defect in NPC1 disease. Investigation of the P450 system in the context of NPC1 dysfunction revealed significant changes in the gene expression of many P450 associated genes across the full lifespan of Npc1-/- mice, decreased activity of cytochrome P450 reductase, and a global decrease of multiple cytochrome P450 catalysed dealkylation reactions. In vivo drug metabolism studies using a prototypic P450 metabolised drug, midazolam, confirmed dysfunction in drug clearance in the Npc1-/- mouse. Expression of the Phase II enzyme uridinediphosphate-glucuronosyltransferase (UGT) was also significantly reduced in Npc1-/- mice. Interestingly, reduced activity within the P450 system was also observed in heterozygous Npc1+/- mice. The reduced activity of P450 enzymes may be the result of bile acid deficiency/imbalance in Npc1-/- mice, as bile acid treatment significantly rescued P450 enzyme activity in Npc1-/- mice and has the potential to be an adjunctive therapy for NPC disease patients. The dysfunction in the cytochrome P450 system were recapitulated in the NPC1 feline model. Additionally, we present the first evidence that there are alterations in the P450 system in NPC1 patients. PMID:27019000

  15. Obesity: The Metabolic Disease, Advances on Drug Discovery and Natural Product Research.

    PubMed

    Castro, Mafalda; Preto, Marco; Vasconcelos, Vitor; Urbatzka, Ralph

    2016-01-01

    Obesity is a global health threat. OECD reported that more than half (52%) of the adult population in the European Union is overweight or obese. Obesity and obesity-related co-morbidities have deep negative effects on morbidity, mortality, professional and personal quality of life. Healthcare costs represent a negative impact of this disease, with an associated economic cost of 100 billion US$ per year in the United States. The most prescribed drugs for obesity treatment worldwide are orlistat, and phentermine/topiramate extended release, while the major prescribed drug for the same disease in the US are exenatide and dapagliflozin. The so far developed drugs, targeting weight loss, have a long history of malignant secondary effects. There is still a lack of efficient and safe drugs to treat obesity and related metabolic complications since in many cases cure cannot be reached by bariatric surgery or healthy lifestyle habits. Terrestrial and aquatic organisms are a promising source of valuable, bioactive compounds, often with interest for human health. Some of the natural compounds or organisms have been used for centuries by humans as traditional medicine foods. In this review, we give insights into the adipose tissue function and development, and the progress in traditional anti-obesity pharmacotherapy. A major focus is to highlight the state of the art of natural compounds with anti-obesity properties and their potential as candidates for drug development; an overview is given about natural compounds derived from different marine animal sources, cyanobacteria, marine phytoplankton, fungus or plants. PMID:27086785

  16. Obesity: The Metabolic Disease, Advances on Drug Discovery and Natural Product Research.

    PubMed

    Castro, Mafalda; Preto, Marco; Vasconcelos, Vitor; Urbatzka, Ralph

    2016-01-01

    Obesity is a global health threat. OECD reported that more than half (52%) of the adult population in the European Union is overweight or obese. Obesity and obesity-related co-morbidities have deep negative effects on morbidity, mortality, professional and personal quality of life. Healthcare costs represent a negative impact of this disease, with an associated economic cost of 100 billion US$ per year in the United States. The most prescribed drugs for obesity treatment worldwide are orlistat, and phentermine/topiramate extended release, while the major prescribed drug for the same disease in the US are exenatide and dapagliflozin. The so far developed drugs, targeting weight loss, have a long history of malignant secondary effects. There is still a lack of efficient and safe drugs to treat obesity and related metabolic complications since in many cases cure cannot be reached by bariatric surgery or healthy lifestyle habits. Terrestrial and aquatic organisms are a promising source of valuable, bioactive compounds, often with interest for human health. Some of the natural compounds or organisms have been used for centuries by humans as traditional medicine foods. In this review, we give insights into the adipose tissue function and development, and the progress in traditional anti-obesity pharmacotherapy. A major focus is to highlight the state of the art of natural compounds with anti-obesity properties and their potential as candidates for drug development; an overview is given about natural compounds derived from different marine animal sources, cyanobacteria, marine phytoplankton, fungus or plants.

  17. Polymorphisms of drug-metabolizing enzymes in healthy nonagenarians and centenarians: difference at GSTT1 locus.

    PubMed

    Taioli, E; Mari, D; Franceschi, C; Bonafè, M; Monti, D; Bertolini, S; Marinelli, D; Garte, S

    2001-02-01

    Drug metabolizing enzymes are involved in the detoxification of several drugs, environmental substances, and carcinogenic compounds, and their polymorphisms have been associated with risk for a variety of cancer. In this paper, we compared the frequency of polymorphisms in cytochrome P450-1A1 gene (CYP1A1), a phase 1 gene (oxidation, activation), and of two polymorphisms of glutathione S-transferase enzymes (GSTM1, GSTT1), two phase 2 genes (conjugation, detoxification). Two groups were studied and compared, i.e., 94 nonagenarians and centenarians and 418 control subjects of younger age. A significant difference in the proportion of nonagenarians and centenarians homozygotes for a GSTT1 deletion (28%) was observed in comparison to control subjects (19%, P = 0.03). The distribution of the other gene polymorphisms did not differ in the two groups. These findings on phase 2 drug-metabolizing enzyme gene polymorphisms may help in disentangling gene-environmental interactions which can have a role in successful aging and longevity, as well as in cancer incidence in the oldest old.

  18. Plant maturity and nitrogen fertilization affected fructan metabolism in harvestable tissues of timothy (Phleum pratense L.).

    PubMed

    Ould-Ahmed, Marouf; Decau, Marie-Laure; Morvan-Bertrand, Annette; Prud'homme, Marie-Pascale; Lafrenière, Carole; Drouin, Pascal

    2014-10-15

    Timothy (Phleum pratense L.) is an important grass forage used for pasture, hay, and silage in regions with cool and humid growth seasons. One of the factors affecting the nutritive value of this grass is the concentration of non-structural carbohydrates (NSC), mainly represented by fructans. NSC concentration depends on multiple factors, making it hardly predictable. To provide a better understanding of NSC metabolism in timothy, the effects of maturity stage and nitrogen (N) fertilization level on biomass, NSC and N-compound concentrations were investigated in the tissues used for forage (leaf blades and stems surrounded by leaf sheaths) of hydroponically grown plants. Moreover, activities and relative expression level of enzymes involved in fructan metabolism were measured in the same tissues. Forage biomass was not altered by the fertilization level but was strongly modified by the stage of development. It increased from vegetative to heading stages while leaf-to-stem biomass ratio decreased. Total NSC concentration, which was not altered by N fertilization level, increased between heading and anthesis due to an accumulation of fructans in leaf blades. Fructan metabolizing enzyme activities (fructosyltransferase-FT and fructan exohydrolase-FEH) were not or only slightly altered by both maturity stage and N fertilization level. Conversely, the relative transcript levels of genes coding for enzymes involved in fructan metabolism were modified by N supply (PpFT1 and Pp6-FEH1) or maturity stage (PpFT2). The relative transcript level of PpFT1 was the highest in low N plants while that of Pp6-FEH1 was the highest in high N plants. Morevoer, transcript level of PpFT1 was negatively correlated with nitrate concentration while that of PpFT2 was positively correlated with sucrose concentration. This distinct regulation of the two genes coding for 6-sucrose:fructan fructosyltransferase (6-SFT) may allow a fine adequation of C allocation towards fructan synthesis in

  19. The impact of skin viability on drug metabolism and permeation -- BSA toxicity on primary keratinocytes.

    PubMed

    Haberland, A; Schreiber, S; Maia, C Santos; Rübbelke, M K; Schaller, M; Korting, H C; Kleuser, B; Schimke, I; Schäfer-Korting, M

    2006-04-01

    For testing cutaneous absorption of drugs, ingredients of cosmetics and also for risk assessment of industrial compounds predictable in vitro test protocols are under investigation using excised skin or reconstructed human epidermis. Since the metabolizing enzymes expressed by viable skin can influence the absorption behaviour of substances by changing their structure and thereby their physicochemical characteristics, the metabolic capacity should be considered in the design of the test protocols of compounds susceptible to metabolism. Then data, generated using viable reconstructed epidermis may reflect the in vivo situation. Interestingly, bovine serum albumin (BSA) commonly used in receptor media in permeation studies to facilitate solubility of highly lipophilic substances strongly inhibited the metabolism of topically applied prednicarbate in reconstructed epidermis. Here, we show that 5% BSA is toxic to reconstructed epidermis and keratinocytes which was consistent with the earlier findings. While media toxicity (deficiency media) was at least partly the cause of both apoptotic and necrotic processes in keratinocytes, BSA only slightly increased the rate of necrotic cells. Moreover, caspase inhibitors did not reduce BSA toxicity. Yet, the results show that BSA toxicity on keratinocytes has to be carefully considered if this protein is used in permeation studies with reconstructed epidermis.

  20. Recent Advances in Understanding and Mitigating Adipogenic and Metabolic Effects of Antipsychotic Drugs

    PubMed Central

    Gohlke, Julia M.; Dhurandhar, Emily J.; Correll, Christoph U.; Morrato, Elaine H.; Newcomer, John W.; Remington, Gary; Nasrallah, Henry A.; Crystal, Stephen; Nicol, Ginger; Allison, David B.

    2012-01-01

    Although offering many benefits for several psychiatric disorders, antipsychotic drugs (APDs) as a class have a major liability in their tendency to promote adiposity, obesity, and metabolic dysregulation in an already metabolically vulnerable population. The past decade has witnessed substantial research aimed at investigating the mechanisms of these adverse effects and mitigating them. On July 11 and 12, 2011, with support from 2 NIH institutes, leading experts convened to discuss current research findings and to consider future research strategies. Five areas where significant advances are being made emerged from the conference: (1) methodological issues in the study of APD effects; (2) unique characteristics and needs of pediatric patients; (3) genetic components underlying susceptibility to APD-induced metabolic effects; (4) APD effects on weight gain and adiposity in relation to their acute effects on glucose regulation and diabetes risk; and (5) the utility of behavioral, dietary, and pharmacological interventions in mitigating APD-induced metabolic side effects. This paper summarizes the major conclusions and important supporting data from the meeting. PMID:22754543

  1. Renal drug metabolism in humans: the potential for drug-endobiotic interactions involving cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT).

    PubMed

    Knights, Kathleen M; Rowland, Andrew; Miners, John O

    2013-10-01

    Although knowledge of human renal cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT) enzymes and their role in xenobiotic and endobiotic metabolism is limited compared with hepatic drug and chemical metabolism, accumulating evidence indicates that human kidney has significant metabolic capacity. Of the drug metabolizing P450s in families 1 to 3, there is definitive evidence for only CYP 2B6 and 3A5 expression in human kidney. CYP 1A1, 1A2, 1B1, 2A6, 2C19, 2D6 and 2E1 are not expressed in human kidney, while data for CYP 2C8, 2C9 and 3A4 expression are equivocal. It is further known that several P450 enzymes involved in the metabolism of arachidonic acid and eicosanoids are expressed in human kidney, CYP 4A11, 4F2, 4F8, 4F11 and 4F12. With the current limited evidence of drug substrates for human renal P450s drug-endobiotic interactions arising from inhibition of renal P450s, particularly effects on arachidonic acid metabolism, appear unlikely. With respect to the UGTs, 1A5, 1A6, 1A7, 1A9, 2B4, 2B7 and 2B17 are expressed in human kidney, whereas UGT 1A1, 1A3, 1A4, 1A8, 1A10, 2B10, 2B11 and 2B15 are not. The most abundantly expressed renal UGTs are 1A9 and 2B7, which play a significant role in the glucuronidation of drugs, arachidonic acid, prostaglandins, leukotrienes and P450 derived arachidonic acid metabolites. Modulation by drug substrates (e.g. NSAIDs) of the intrarenal activity of UGT1A9 and UGT2B7 has the potential to perturb the metabolism of renal mediators including aldosterone, prostaglandins and 20-hydroxyeicosatetraenoic acid, thus disrupting renal homeostasis. PMID:23362865

  2. High anion gap metabolic acidosis secondary to pyroglutamic aciduria (5-oxoprolinuria): association with prescription drugs and malnutrition.

    PubMed

    Brooker, G; Jeffery, J; Nataraj, T; Sair, M; Ayling, R

    2007-07-01

    Two cases of High Anion Gap Metabolic Acidosis (HAGMA) due to pyroglutamic acid (5-oxoproline) are described. In both cases the HAGMA developed during an episode of hospital treatment, in conjunction with paracetamol and antibiotic prescription, and the surviving patient made an uneventful recovery after the drugs were withdrawn. Clinicians need to be aware of this cause for metabolic acidosis because it may be a more common metabolic disturbance in compromised patients than would be expected, and the discontinuation of drugs implicated in the aetiology is therapeutic.

  3. Drug-metabolizing enzymes, polymorphisms and interindividual response to environmental toxicants.

    PubMed

    Nebert, D W

    2000-09-01

    Individual risk of toxicity or cancer reflects the amount of exposure to environmental agents, combined with one's underlying genetic predisposition. More than six dozen human ecogenetic polymorphisms have been described; whereas some of these have been demonstrated to be associated with altered risks of toxicity or cancer, others presently remain equivocal and require further study. Thus, genetic differences in the regulation, expression and activity of "environmental susceptibility genes" can be decisive in defining susceptibility to toxicity or cancer. "Drug-metabolizing enzymes" (DMEs) are regarded as one class of environmental susceptibility genes. DME genes have actually existed on this planet for more than 2.5 billion years, and might more appropriately be named "effector-metabolizing enzymes." Receptors controlling DME levels have been called "DME receptors." DMEs have functioned in many critical life processes in prokaryotes and, more recently, in countless basic functions in plants and animals - events that evolved long before the existence of pharmaceutical companies and apothecaries. DME genes exist in every eukaryotic cell and probably in all prokaryotes. Virtually all environmental agents act as either agonists or antagonists - in competing with endogenous ligands that bind to DME receptors and/or competing as substrates for the DMEs. Over the past decade it has become clear that each of us has our own "individual fingerprint" of unique alleles coding for DMEs. The underlying genetic predisposition of each patient will reflect combinations of poor- and extensive-metabolizer phenotypes; if these enzymes cooperate in the same metabolic pathway for any given drug or environmental agent, such ecogenetic variability might be synergistic and lead to as much as 30- or >40-fold differences in activation or degradation. The end result can be large interindividual differences in risk of environmentally caused toxicity or cancer.

  4. Do androgen deprivation drugs affect the immune cross-talk between mononuclear and prostate cancer cells?

    PubMed

    Salman, Hertzel; Bergman, Michael; Blumberger, Naava; Djaldetti, Meir; Bessler, Hanna

    2014-02-01

    The aim of the study was to examine the effect of androgen deprivation drugs, i.e. leuprolide and bicalutamide on the immune cross-talk between human peripheral blood mononuclear cells (PBMC) and cells from PC-3 and LNCaP human prostate cancer lines. PBMC, PC-3 and LNCaP were separately incubated without and with two androgen-deprivation drugs, i.e. leuprolide and bicalutamide, and the secretion of IL-1β, IL-6, IL-1ra and IL-10 was examined. In addition, the effect of both drugs on the production of those cytokines was carried out after 24 hours incubation of PBMC with both types of cancer cells. Leuprolide or bicalutamide did not affect the production of the cytokines by PBMC or by the prostate cancer cells from the two lines. Incubation of PBMC with PC-3 or LNCaP cells caused increased production of IL-1β, IL-6 and IL-10 as compared with PBMC incubated without malignant cells. While 10(-7) M and 10(-8) M of leuprolide caused a decreased secretion of IL-1β by PBMC previously incubated with prostate cancer cells without the drug, bicalutamide did not affect this PBMC activity at any drug concentration. This observation suggests the existence of an additional mechanism explaining the effect of androgen deprivation therapy in prostate cancer patients.

  5. Relevance of drug metabolizing enzyme activity modulation by tea polyphenols in the inhibition of esophageal tumorigenesis.

    PubMed

    Maliakal, Pius; Sankpal, Umesh T; Basha, Riyaz; Maliakal, Cima; Ledford, Andrea; Wanwimolruk, Sompon

    2011-09-01

    Tea is a popular, socially accepted, drink that is enjoyed by millions of people. A growing body of evidence suggests that moderate consumption of tea may protect against several forms of cancer. It is also known that bioactivation of precarcinogens and detoxification of ultimate carcinogens is carried out mainly by drug metabolizing enzymes such as cytochrome P450 (CYP). The present study investigates the effect of tea consumption on modulating CYP and phase II conjugating enzymes, and their association in the chemopreventive effect against esophageal tumorigenesis using both in vitro and in vivo techniques. Female Wistar rats were given aqueous solutions (2% w/v) of six different teas, standard green tea extract (GTE) (0.5% w/v), and dandelion tea (2% w/v) as the sole source of fluid for two weeks prior to and during the entire period of tumour induction (12 weeks). Animals were gavaged with 0.5 mg/kg N-nitrosomethylbenzylamine (NMBA) twice weekly for 12 weeks for esophageal tumor induction and the activities of different CYP isoforms and phase II enzymes were determined in the liver microsomes or cytosols. GTE, green tea and Dandelion tea caused decrease in tumour multiplication, tumour size and tumour volume; however, none of these tea preparations altered tumour incidence. No appreciable changes in drug metabolizing enzyme activity were observed in the treatment groups. Thus, the modulations in the activities of CYP 1A1/ 1A2 and CYP2E enzymes, by pre-treatment with green and dandelion teas, observed in our earlier experiments, seem to be compensated by the tumor inducing agent, NMBA. The balance between phase I carcinogen-activating enzymes and phase II detoxifying enzymes could be important in determining the risk of developing chemically-induced cancer and the present study in conjunction with the previous observations suggest a possible role of drug metabolizing enzymes in the anticancer effect of tea.

  6. Drug development for exceptionally rare metabolic diseases: challenging but not impossible

    PubMed Central

    2013-01-01

    Background We studied to what extent the level of scientific knowledge on exceptionally rare metabolic inherited diseases and their potential orphan medicinal products is associated with sponsors deciding to apply for an orphan designation at the US Food and Drug Administration (FDA) or the European Medicines Agency (EMA). Methods All metabolic diseases with a genetic cause and prevalence of less than 10 patients per 1 million of the population were selected from the ‘Orphanet database of Rare diseases’. The outcome of interest was the application for an orphan designation at FDA or EMA. The level of publicly available knowledge of the disease and drug candidate before an orphan designation application was defined as whether the physiological function corresponding with the pathologic gene and initiation of the pathophysiological pathway was known, whether an appropriate animal study was identified for the disease, whether preclinical proof of concept was ascertained and the availability of data in humans. Other determinants included in the study were metabolic disease class, the prevalence of the disease, prognosis and time of first description of the disease in the literature. Univariate relative risks (RRs) and 95% confidence intervals (CIs) of an orphan designation application were calculated for each of these determinants. In addition, a multivariate Cox regression analysis was conducted (Forward LR). Results In total, 166 rare metabolic genetic diseases were identified and included in the analysis. For only 42 (25%) of the diseases an orphan designation application was submitted at either FDA or EMA before January 2012. The multivariate analysis identified preclinical proof of concept of a potential medicinal product as major knowledge related determinant associated with an orphan designation application (RRadj 3.9, 95% CI 1.9-8.3) and confirmed that prevalence of the disease is also associated with filing an application for an orphan designation (RRadj 2

  7. Increasing Phosphatidylinositol (4,5)-Bisphosphate Biosynthesis Affects Basal Signaling and Chloroplast Metabolism in Arabidopsis thaliana

    PubMed Central

    Im, Yang Ju; Smith, Caroline M.; Phillippy, Brian Q.; Strand, Deserah; Kramer, David M.; Grunden, Amy M.; Boss, Wendy F.

    2014-01-01

    One challenge in studying the second messenger inositol(1,4,5)-trisphosphate (InsP3) is that it is present in very low amounts and increases only transiently in response to stimuli. To identify events downstream of InsP3, we generated transgenic plants constitutively expressing the high specific activity, human phosphatidylinositol 4-phosphate 5-kinase Iα (HsPIPKIα). PIP5K is the enzyme that synthesizes phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P2); this reaction is flux limiting in InsP3 biosynthesis in plants. Plasma membranes from transgenic Arabidopsis expressing HsPIPKIα had 2–3 fold higher PIP5K specific activity, and basal InsP3 levels in seedlings and leaves were >2-fold higher than wild type. Although there was no significant difference in photosynthetic electron transport, HsPIPKIα plants had significantly higher starch (2–4 fold) and 20% higher anthocyanin compared to controls. Starch content was higher both during the day and at the end of dark period. In addition, transcripts of genes involved in starch metabolism such as SEX1 (glucan water dikinase) and SEX4 (phosphoglucan phosphatase), DBE (debranching enzyme), MEX1 (maltose transporter), APL3 (ADP-glucose pyrophosphorylase) and glucose-6-phosphate transporter (Glc6PT) were up-regulated in the HsPIPKIα plants. Our results reveal that increasing the phosphoinositide (PI) pathway affects chloroplast carbon metabolism and suggest that InsP3 is one component of an inter-organelle signaling network regulating chloroplast metabolism. PMID:27135490

  8. Maternal Obesity Affects Fetal Neurodevelopmental and Metabolic Gene Expression: A Pilot Study

    PubMed Central

    Edlow, Andrea G.; Vora, Neeta L.; Hui, Lisa; Wick, Heather C.; Cowan, Janet M.; Bianchi, Diana W.

    2014-01-01

    Objective One in three pregnant women in the United States is obese. Their offspring are at increased risk for neurodevelopmental and metabolic morbidity. Underlying molecular mechanisms are poorly understood. We performed a global gene expression analysis of mid-trimester amniotic fluid cell-free fetal RNA in obese versus lean pregnant women. Methods This prospective pilot study included eight obese (BMI≥30) and eight lean (BMI<25) women undergoing clinically indicated mid-trimester genetic amniocentesis. Subjects were matched for gestational age and fetal sex. Fetuses with abnormal karyotype or structural anomalies were excluded. Cell-free fetal RNA was extracted from amniotic fluid and hybridized to whole genome expression arrays. Genes significantly differentially regulated in 8/8 obese-lean pairs were identified using paired t-tests with the Benjamini-Hochberg correction (false discovery rate of <0.05). Biological interpretation was performed with Ingenuity Pathway Analysis and the BioGPS gene expression atlas. Results In fetuses of obese pregnant women, 205 genes were significantly differentially regulated. Apolipoprotein D, a gene highly expressed in the central nervous system and integral to lipid regulation, was the most up-regulated gene (9-fold). Apoptotic cell death was significantly down-regulated, particularly within nervous system pathways involving the cerebral cortex. Activation of the transcriptional regulators estrogen receptor, FOS, and STAT3 was predicted in fetuses of obese women, suggesting a pro-estrogenic, pro-inflammatory milieu. Conclusion Maternal obesity affects fetal neurodevelopmental and metabolic gene expression as early as the second trimester. These findings may have implications for postnatal neurodevelopmental and metabolic abnormalities described in the offspring of obese women. PMID:24558408

  9. Potato Snakin-1 Gene Silencing Affects Cell Division, Primary Metabolism, and Cell Wall Composition1[W

    PubMed Central

    Nahirñak, Vanesa; Almasia, Natalia Inés; Fernandez, Paula Virginia; Hopp, Horacio Esteban; Estevez, José Manuel; Carrari, Fernando; Vazquez-Rovere, Cecilia

    2012-01-01

    Snakin-1 (SN1) is an antimicrobial cysteine-rich peptide isolated from potato (Solanum tuberosum) that was classified as a member of the Snakin/Gibberellic Acid Stimulated in Arabidopsis protein family. In this work, a transgenic approach was used to study the role of SN1 in planta. Even when overexpressing SN1, potato lines did not show remarkable morphological differences from the wild type; SN1 silencing resulted in reduced height, which was accompanied by an overall reduction in leaf size and severe alterations of leaf shape. Analysis of the adaxial epidermis of mature leaves revealed that silenced lines had 70% to 90% increases in mean cell size with respect to wild-type leaves. Consequently, the number of epidermal cells was significantly reduced in these lines. Confocal microscopy analysis after agroinfiltration of Nicotiana benthamiana leaves showed that SN1-green fluorescent protein fusion protein was localized in plasma membrane, and bimolecular fluorescence complementation assays revealed that SN1 self-interacted in vivo. We further focused our study on leaf metabolism by applying a combination of gas chromatography coupled to mass spectrometry, Fourier transform infrared spectroscopy, and spectrophotometric techniques. These targeted analyses allowed a detailed examination of the changes occurring in 46 intermediate compounds from primary metabolic pathways and in seven cell wall constituents. We demonstrated that SN1 silencing affects cell division, leaf primary metabolism, and cell wall composition in potato plants, suggesting that SN1 has additional roles in growth and development beyond its previously assigned role in plant defense. PMID:22080603

  10. The Aldo-Keto Reductase Superfamily and its Role in Drug Metabolism and Detoxification

    PubMed Central

    Barski, Oleg A.; Tipparaju, Srinivas M.; Bhatnagar, Aruni

    2008-01-01

    The Aldo-Keto Reductase (AKR) superfamily comprises of several enzymes that catalyze redox transformations involved in biosynthesis, intermediary metabolism and detoxification. Substrates of the family include glucose, steroids, glycosylation end products, lipid peroxidation products, and environmental pollutants. These proteins adopt a (β/α)8 barrel structural motif interrupted by a number of extraneous loops and helixes that vary between proteins and bring structural identity to individual families. The human AKR family differs from the rodent families. Due to their broad substrate specificity, AKRs play an important role in the Phase II detoxification of a large number of pharmaceuticals, drugs, and xenobiotics. PMID:18949601

  11. Arachidonic Acid and Eicosapentaenoic Acid Metabolism in Juvenile Atlantic Salmon as Affected by Water Temperature.

    PubMed

    Norambuena, Fernando; Morais, Sofia; Emery, James A; Turchini, Giovanni M

    2015-01-01

    Salmons raised in aquaculture farms around the world are increasingly subjected to sub-optimal environmental conditions, such as high water temperatures during summer seasons. Aerobic scope increases and lipid metabolism changes are known plasticity responses of fish for a better acclimation to high water temperature. The present study aimed at investigating the effect of high water temperature on the regulation of fatty acid metabolism in juvenile Atlantic salmon fed different dietary ARA/EPA ratios (arachidonic acid, 20:4n-6/ eicosapentaenoic acid, 20:5n-3), with particular focus on apparent in vivo enzyme activities and gene expression of lipid metabolism pathways. Three experimental diets were formulated to be identical, except for the ratio EPA/ARA, and fed to triplicate groups of Atlantic salmon (Salmo salar) kept either at 10°C or 20°C. Results showed that fatty acid metabolic utilisation, and likely also their dietary requirements for optimal performance, can be affected by changes in their relative levels and by environmental temperature in Atlantic salmon. Thus, the increase in temperature, independently from dietary treatment, had a significant effect on the β-oxidation of a fatty acid including EPA, as observed by the apparent in vivo enzyme activity and mRNA expression of pparα -transcription factor in lipid metabolism, including β-oxidation genes- and cpt1 -key enzyme responsible for the movement of LC-PUFA from the cytosol into the mitochondria for β-oxidation-, were both increased at the higher water temperature. An interesting interaction was observed in the transcription and in vivo enzyme activity of Δ5fad-time-limiting enzyme in the biosynthesis pathway of EPA and ARA. Such, at lower temperature, the highest mRNA expression and enzyme activity was recorded in fish with limited supply of dietary EPA, whereas at higher temperature these were recorded in fish with limited ARA supply. In consideration that fish at higher water temperature

  12. Arachidonic Acid and Eicosapentaenoic Acid Metabolism in Juvenile Atlantic Salmon as Affected by Water Temperature

    PubMed Central

    Norambuena, Fernando; Morais, Sofia; Emery, James A.; Turchini, Giovanni M.

    2015-01-01

    Salmons raised in aquaculture farms around the world are increasingly subjected to sub-optimal environmental conditions, such as high water temperatures during summer seasons. Aerobic scope increases and lipid metabolism changes are known plasticity responses of fish for a better acclimation to high water temperature. The present study aimed at investigating the effect of high water temperature on the regulation of fatty acid metabolism in juvenile Atlantic salmon fed different dietary ARA/EPA ratios (arachidonic acid, 20:4n-6/ eicosapentaenoic acid, 20:5n-3), with particular focus on apparent in vivo enzyme activities and gene expression of lipid metabolism pathways. Three experimental diets were formulated to be identical, except for the ratio EPA/ARA, and fed to triplicate groups of Atlantic salmon (Salmo salar) kept either at 10°C or 20°C. Results showed that fatty acid metabolic utilisation, and likely also their dietary requirements for optimal performance, can be affected by changes in their relative levels and by environmental temperature in Atlantic salmon. Thus, the increase in temperature, independently from dietary treatment, had a significant effect on the β-oxidation of a fatty acid including EPA, as observed by the apparent in vivo enzyme activity and mRNA expression of pparα -transcription factor in lipid metabolism, including β-oxidation genes- and cpt1 -key enzyme responsible for the movement of LC-PUFA from the cytosol into the mitochondria for β-oxidation-, were both increased at the higher water temperature. An interesting interaction was observed in the transcription and in vivo enzyme activity of Δ5fad–time-limiting enzyme in the biosynthesis pathway of EPA and ARA. Such, at lower temperature, the highest mRNA expression and enzyme activity was recorded in fish with limited supply of dietary EPA, whereas at higher temperature these were recorded in fish with limited ARA supply. In consideration that fish at higher water temperature

  13. Depletion of PINK1 affects mitochondrial metabolism, calcium homeostasis and energy maintenance.

    PubMed

    Heeman, Bavo; Van den Haute, Chris; Aelvoet, Sarah-Ann; Valsecchi, Federica; Rodenburg, Richard J; Reumers, Veerle; Debyser, Zeger; Callewaert, Geert; Koopman, Werner J H; Willems, Peter H G M; Baekelandt, Veerle

    2011-04-01

    Loss-of-function mutations in the gene encoding the mitochondrial PTEN-induced putative kinase 1 (PINK1) are a major cause of early-onset familial Parkinson's disease (PD). Recent studies have highlighted an important function for PINK1 in clearing depolarized mitochondria by mitophagy. However, the role of PINK1 in mitochondrial and cellular functioning in physiological conditions is still incompletely understood. Here, we investigate mitochondrial and cellular calcium (Ca(2+)) homeostasis in PINK1-knockdown and PINK1-knockout mouse cells, both in basal metabolic conditions and after physiological stimulation, using unbiased automated live single-cell imaging in combination with organelle-specific fluorescent probes. Our data reveal that depletion of PINK1 induces moderate fragmentation of the mitochondrial network, mitochondrial membrane depolarization and increased production of reactive oxygen species. This results in reduced uptake of Ca(2+) by mitochondria after physiological stimulation. As a consequence, cells with knockdown or knockout of PINK1 display impaired mitochondrial ATP synthesis, which is exacerbated under conditions of increased ATP demand, thereby affecting cytosolic Ca(2+) extrusion. The impairment in energy maintenance was confirmed in the brain of PINK1-knockout mice by in vivo bioluminescence imaging. Our findings demonstrate a key role for PINK1 in the regulation of mitochondrial homeostasis and energy metabolism under physiological conditions. PMID:21385841

  14. Incubation temperature affects growth and energy metabolism in blue tit nestlings.

    PubMed

    Nord, Andreas; Nilsson, Jan-Åke

    2011-11-01

    Because the maintenance of proper developmental temperatures during avian incubation is costly to parents, embryos of many species experience pronounced variation in incubation temperature. However, the effects of such temperature variation on nestling development remain relatively unexplored. To investigate this, we artificially incubated wild blue tit (Cyanistes caeruleus L.) clutches at 35.0°, 36.5°, or 38.0°C for two-thirds of the incubation period. We returned clutches to their original nests before hatching and subsequently recorded nestling growth and resting metabolic rate. The length of the incubation period decreased with temperature, whereas hatching success increased. Nestlings from the lowest incubation temperature group had shorter tarsus lengths at 2 weeks of age, but body mass and wing length were not affected by temperature. In addition, nestlings from the lowest temperature group had a significantly higher resting metabolic rate compared with mid- and high-temperature nestlings, which may partly explain observed size differences between the groups. These findings suggest that nest microclimate can influence nestling phenotype, but whether observed differences carry over to later life-history stages remains unknown.

  15. Failure of caffeine to affect metabolism during 60 min submaximal exercise.

    PubMed

    Titlow, L W; Ishee, J H; Riggs, C E

    1991-01-01

    Caffeine consumption prior to athletic performance has become commonplace. The usual dosage is approximately 200 mg, a level of caffeine ingestion equivalent to two cups of brewed coffee. This study was designed to examine the effects of a common level of caffeine ingestion, specifically 200 mg, on metabolism during submaximal exercise performance in five males. The subjects performed two 60-min monitored treadmill workouts at 60% maximal heart rate during a 2-week period. The subjects were randomly assigned, double-blind to receive a caffeine or placebo capsule 60 min prior to exercise. Testing was performed in the afternoon following a midnight fast. Venous blood was withdrawn pre-exercise, every 15 min during the workout, and 10 min after recovery. Blood was analysed for free fatty acid, triglycerides, glucose, lactic acid, haemoglobin and haematocrit. The respiratory exchange ratio (R), perceived exertion (RPE) and oxygen uptake were measured every 4 min during exercise. An examination of the data with repeated-measures ANOVA revealed no significant differences between the two groups. Within the limitations of the study, it was concluded that 200 mg caffeine failed to affect metabolism during 60 min submaximal exercise.

  16. Testosterone affects hormone-sensitive lipase (HSL) activity and lipid metabolism in the left ventricle.

    PubMed

    Langfort, Jozef; Jagsz, Slawomir; Dobrzyn, Pawel; Brzezinska, Zofia; Klapcinska, Barbara; Galbo, Henrik; Gorski, Jan

    2010-09-01

    Fatty acids, which are the major cardiac fuel, are derived from lipid droplets stored in cardiomyocytes, among other sources. The heart expresses hormone-sensitive lipase (HSL), which regulates triglycerides (TG) breakdown, and the enzyme is under hormonal control. Evidence obtained from adipose tissue suggests that testosterone regulates HSL activity. To test whether this is also true in the heart, we measured HSL activity in the left ventricle of sedentary male rats that had been treated with testosterone supplementation or orchidectomy with or without testosterone substitution. Left ventricle HSL activity against TG was significantly elevated in intact rats supplemented with testosterone. HSL activity against both TG and diacylglyceride was reduced by orchidectomy, whereas testosterone replacement fully reversed this effect. Moreover, testosterone increased left ventricle free fatty acid levels, caused an inhibitory effect on carbohydrate metabolism in the heart, and elevated left ventricular phosphocreatine and ATP levels as compared to control rats. These data indicate that testosterone is involved in cardiac HSL activity regulation which, in turn, may affect cardiac lipid and carbohydrate metabolism.

  17. Failure of caffeine to affect metabolism during 60 min submaximal exercise.

    PubMed

    Titlow, L W; Ishee, J H; Riggs, C E

    1991-01-01

    Caffeine consumption prior to athletic performance has become commonplace. The usual dosage is approximately 200 mg, a level of caffeine ingestion equivalent to two cups of brewed coffee. This study was designed to examine the effects of a common level of caffeine ingestion, specifically 200 mg, on metabolism during submaximal exercise performance in five males. The subjects performed two 60-min monitored treadmill workouts at 60% maximal heart rate during a 2-week period. The subjects were randomly assigned, double-blind to receive a caffeine or placebo capsule 60 min prior to exercise. Testing was performed in the afternoon following a midnight fast. Venous blood was withdrawn pre-exercise, every 15 min during the workout, and 10 min after recovery. Blood was analysed for free fatty acid, triglycerides, glucose, lactic acid, haemoglobin and haematocrit. The respiratory exchange ratio (R), perceived exertion (RPE) and oxygen uptake were measured every 4 min during exercise. An examination of the data with repeated-measures ANOVA revealed no significant differences between the two groups. Within the limitations of the study, it was concluded that 200 mg caffeine failed to affect metabolism during 60 min submaximal exercise. PMID:1856908

  18. Food odors trigger an endocrine response that affects food ingestion and metabolism.

    PubMed

    Lushchak, Oleh V; Carlsson, Mikael A; Nässel, Dick R

    2015-08-01

    Food odors stimulate appetite and innate food-seeking behavior in hungry animals. The smell of food also induces salivation and release of gastric acid and insulin. Conversely, sustained odor exposure may induce satiation. We demonstrate novel effects of food odors on food ingestion, metabolism and endocrine signaling in Drosophila melanogaster. Acute exposure to attractive vinegar odor triggers a rapid and transient increase in circulating glucose, and a rapid upregulation of genes encoding the glucagon-like hormone adipokinetic hormone (AKH), four insulin-like peptides (DILPs) and some target genes in peripheral tissues. Sustained exposure to food odors, however, decreases food intake. Hunger-induced strengthening of synaptic signaling from olfactory sensory neurons (OSNs) to brain neurons increases food-seeking behavior, and conversely fed flies display reduced food odor sensitivity and feeding. We show that increasing the strength of OSN signaling chronically by genetic manipulation of local peptide neuromodulation reduces feeding, elevates carbohydrates and diminishes lipids. Furthermore, constitutively strengthened odor sensitivity altered gene transcripts for AKH, DILPs and some of their targets. Thus, we show that food odor can induce a transient anticipatory endocrine response, and that boosted sensitivity to this odor affects food intake, as well as metabolism and hormonal signaling.

  19. In vivo cytochrome P450 drug metabolizing enzyme characterization using surface-enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Yanfang; Bachmann, Kenneth A.; Cameron, Brent D.

    2003-07-01

    The development of a rapid, inexpensive, and accurate in vivo phenotyping methodology for characterizing drug-metabolizing phenotypes with reference to the cytochrome P450 (CYP450) enzymes would be very beneficial. In terms of application, in the wake of the human genome project, considerable interest is focused on the development of new drugs whose uses will be tailored to specific genetic polymorphisms, and on the individualization of dosing regimens that are also tailored to meet individual patient needs depending upon genotype. In this investigation, chemical probes for CYP450 enzymes were characterized and identified with Raman spectroscopy. Furthermore, gold-based metal colloid clusters were utilized to generate surface enhanced Raman spectra for each of the chemical probes. Results will be presented demonstrating the ability of SERS to identify minute quantities of these probes on the order needed for in vivo application.

  20. Factors Affecting the Absorption, Metabolism, and Excretion of Cocoa Flavanols in Humans.

    PubMed

    Cifuentes-Gomez, Tania; Rodriguez-Mateos, Ana; Gonzalez-Salvador, Isidro; Alañon, María Elena; Spencer, Jeremy P E

    2015-09-01

    Cocoa is rich in a subclass of flavonoids known as flavanols, the cardiovascular health benefits of which have been extensively reported. The appearance of flavanol metabolites in the systemic circulation after flavanol-rich food consumption is likely to mediate the physiological effects on the vascular system, and these levels are influenced by numerous factors, including food matrix, processing, intake, age, gender, or genetic polymorphisms, among others. This review will focus on our current understanding of factors affecting the absorption, metabolism, and excretion of cocoa flavanols in humans. Second, it will identify gaps in these contributing factors that need to be addressed to conclusively translate our collective knowledge into the context of public health, dietary guidelines, and evidence-based dietary recommendations.

  1. 3-Bromopyruvate induces rapid human prostate cancer cell death by affecting cell energy metabolism, GSH pool and the glyoxalase system.

    PubMed

    Valenti, Daniela; Vacca, Rosa A; de Bari, Lidia

    2015-12-01

    3-bromopyruvate (3-BP) is an anti-tumour drug effective on hepatocellular carcinoma and other tumour cell types, which affects both glycolytic and mitochondrial targets, depleting cellular ATP pool. Here we tested 3-BP on human prostate cancer cells showing, differently from other tumour types, efficient ATP production and functional mitochondrial metabolism. We found that 3-BP rapidly induced cultured androgen-insensitive (PC-3) and androgen-responsive (LNCaP) prostate cancer cell death at low concentrations (IC(50) values of 50 and 70 μM, respectively) with a multimodal mechanism of action. In particular, 3-BP-treated PC-3 cells showed a selective, strong reduction of glyceraldeide 3-phosphate dehydrogenase activity, due to the direct interaction of the drug with the enzyme. Moreover, 3-BP strongly impaired both glutamate/malate- and succinate-dependent mitochondrial respiration, membrane potential generation and ATP synthesis, concomitant with the inhibition of respiratory chain complex I, II and ATP synthase activities. The drastic reduction of cellular ATP levels and depletion of GSH pool, associated with significant increase in cell oxidative stress, were found after 3-BP treatment of PC-3 cells. Interestingly, the activity of both glyoxalase I and II, devoted to the elimination of the cytotoxic methylglyoxal, was strongly inhibited by 3-BP. Both N-acetylcysteine and aminoguanidine, GSH precursor and methylglyoxal scavenger, respectively, prevented 3-BP-induced PC-3 cell death, showing that impaired cell antioxidant and detoxifying capacities are crucial events leading to cell death. The provided information on the multi-target cytotoxic action of 3-BP, finally leading to PC-3 cell necrosis, might be useful for future development of 3-BP as a therapeutic option for prostate cancer treatment. PMID:26530987

  2. Quantitative analysis of drug effects at the whole-body level: a case study for glucose metabolism in malaria patients.

    PubMed

    Snoep, Jacky L; Green, Kathleen; Eicher, Johann; Palm, Daniel C; Penkler, Gerald; du Toit, Francois; Walters, Nicolas; Burger, Robert; Westerhoff, Hans V; van Niekerk, David D

    2015-12-01

    We propose a hierarchical modelling approach to construct models for disease states at the whole-body level. Such models can simulate effects of drug-induced inhibition of reaction steps on the whole-body physiology. We illustrate the approach for glucose metabolism in malaria patients, by merging two detailed kinetic models for glucose metabolism in the parasite Plasmodium falciparum and the human red blood cell with a coarse-grained model for whole-body glucose metabolism. In addition we use a genome-scale metabolic model for the parasite to predict amino acid production profiles by the malaria parasite that can be used as a complex biomarker. PMID:26614654

  3. High-throughput screening approaches for investigating drug metabolism and pharmacokinetics.

    PubMed

    Roberts, S A

    2001-01-01

    1. High-throughput screening approaches have been adopted throughout the pharmaceutical industry to aid in the rapid discovery of new chemical entities. Because it is now well recognized that the selection of a robust candidate requires a balance of potency, safety and pharmacokinetics, the role of drug metabolism departments has widened from their traditional one of supporting drug development to include the screening of compounds during the discovery process. To put drug metabolism and pharmacokinetic (DMPK) studies in context, the evolving role of DMPK screening in the drug discovery strategy of pharmaceutical companies will be discussed and a generalized approach will be presented. 2. With the increasing numbers of compounds requiring screening, DMPK optimization methods have had to be adapted for high throughput. There have been many developments in this field over the past decade and this review will focus on the high-throughput DMPK screening methodologies used today and in the recent past. 3. In vitro and in silico (computer-based) methods have proven most amenable to high-throughput approaches and these will firm the bulk of the review, but some advances with in vivo methods will also be discussed. As there has been a vast increase in published material on the topic of high-throughput DMPK methodologies in the past 10 years, it would be impossible to cover every method in detail, so this review will concentrate on the key areas and refer the reader to other, more detailed reviews wherever possible. 4. Most high-throughput methods would not be possible without the enabling technologies of computing, automation, new sample preparation technologies, and highly sensitive and selective detection systems, and these will also be reviewed. 5. The advantages and disadvantages of the screening methods will be presented, in particular the issue of handling the false-positives and -negatives that arise. 6. In concluding the review, future developments in this field

  4. A palatable hyperlipidic diet causes obesity and affects brain glucose metabolism in rats

    PubMed Central

    2011-01-01

    Background We have previously shown that either the continuous intake of a palatable hyperlipidic diet (H) or the alternation of chow (C) and an H diet (CH regimen) induced obesity in rats. Here, we investigated whether the time of the start and duration of these feeding regimens are relevant and whether they affect brain glucose metabolism. Methods Male Wistar rats received C, H, or CH diets during various periods of their life spans: days 30-60, days 30-90, or days 60-90. Experiments were performed the 60th or the 90th day of life. Rats were killed by decapitation. The glucose, insulin, leptin plasma concentration, and lipid content of the carcasses were determined. The brain was sliced and incubated with or without insulin for the analysis of glucose uptake, oxidation, and the conversion of [1-14C]-glucose to lipids. Results The relative carcass lipid content increased in all of the H and CH groups, and the H30-60 and H30-90 groups had the highest levels. Groups H30-60, H30-90, CH30-60, and CH30-90 exhibited a higher serum glucose level. Serum leptin increased in all H groups and in the CH60-90 and CH30-90 groups. Serum insulin was elevated in the H30-60, H60-90, CH60-90, CH30-90 groups. Basal brain glucose consumption and hypothalamic insulin receptor density were lower only in the CH30-60 group. The rate of brain lipogenesis was increased in the H30-90 and CH30-90 groups. Conclusion These findings indicate that both H and CH diet regimens increased body adiposity independent treatment and the age at which treatment was started, whereas these diets caused hyperglycemia and affected brain metabolism when started at an early age. PMID:21943199

  5. In-vitro synthesis of drug metabolites and their screening/characterization using liquid chromatography-mass spectrometry (LC-MS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drug metabolism is a biochemical process by which drugs and xenobiotics are chemically modified to metabolites, primarily by liver enzymes. Metabolites may sometimes affect cellular therapeutic or toxicological processes, therefore knowledge of metabolic processes is essential for understanding drug...

  6. Hepatic cell lines for drug hepatotoxicity testing: limitations and strategies to upgrade their metabolic competence by gene engineering.

    PubMed

    Donato, M Teresa; Jover, Ramiro; Gómez-Lechón, M José

    2013-11-01

    One key issue in the pharmaceutical development of new compounds is knowledge on metabolism, the enzymes involved and the potential hepatotoxicity of a drug. Primary cultured hepatocytes are a valuable in vitro model for drug metabolism studies. However, human hepatocytes show phenotypic instability and have restricted accessibility and high batch-to-batch functional variability, which seriously complicates their use in routine testing. Therefore, several liver-derived cell models have been developed for drug metabolism and hepatotoxicity screening to circumvent these drawbacks. Hepatoma cell lines offer important advantages, availability, an unlimited life span and a stable phenotype, thus rendering them suitable models for such studies. However, currently available human hepatoma cell lines are not a good alternative to cultured hepatocytes as they show very limited expression for most drug-metabolising enzymes. Other approaches have been developed to generate immortalised hepatic cells with metabolic competence (use of plasmids encoding immortalising genes to transform human hepatocytes, cell lines obtained from transgenic animals, hepatocytomes or hydrid cells). Recombinant models heterologously expressing cytochrome P450 enzymes in hepatoma cells have also been generated, and are widely used in drug metabolism and toxicity evaluations. In recent years, new approaches to up-regulate the expression of drug-biotransformation enzymes in human cell lines (i.e., transfection with the expression vectors encoding key hepatic transcription factors) have also been investigated. This paper reviews the features of liver-derived cell lines, their suitability for drug metabolism and hepatotoxicity studies, and the state-of-the-art strategies pursued to generate metabolically competent hepatic cell lines.

  7. Treatment with D-penicillamine or zinc sulphate affects copper metabolism and improves but not normalizes antioxidant capacity parameters in Wilson disease.

    PubMed

    Gromadzka, Grażyna; Grażyna, Gromadzka; Karpińska, Agata; Agata, Karpińska; Przybyłkowski, Adam; Adam, Przybyłkowski; Litwin, Tomasz; Tomasz, Litwin; Wierzchowska-Ciok, Agata; Agata, Wierzchowska-Ciok; Dzieżyc, Karolina; Karolina, Dzieżyc; Chabik, Grzegorz; Grzegorz, Chabik; Członkowska, Anna; Anna, Członkowska

    2014-02-01

    Copper accumulation in tissues due to a biallelic pathogenic mutation of the gene: ATP7B results in a clinical phenotype known as Wilson disease (WD). Aberrations in copper homeostasis can create favourable conditions for superoxide-yielding redox cycling and oxidative tissue damage. Drugs used in WD treatment aim to remove accumulated copper and normalise the free copper concentration in the blood. In the current study the effect of decoppering treatment on copper metabolism and systemic antioxidant capacity parameters was analyzed. Treatment naïve WD patients (TNWD) (n = 33), those treated with anti-copper drugs (TWD) (n = 99), and healthy controls (n = 99) were studied. Both TNWD and TWD patients characterised with decreased copper metabolism parameters, as well as decreased total antioxidant potential (AOP), glutathione (GSH) level, activity of catalase, glutathione peroxidase (GPx), and S-transferase glutathione, compared to controls. TWD patients had significantly lower copper metabolism parameters, higher total AOP and higher levels of GSH than TWD individuals; however, no difference was observed between these two patient groups with respect to the rest of the antioxidant capacity parameters. Patients who had undergone treatment with D-penicillamine or zinc sulphate did not differ with respect to copper metabolism or antioxidant capacity parameters, with the exception of GPx that was lower in D-penicillamine treated individuals. These data suggest that anti-copper treatment affects copper metabolism as well as improves, but does not normalize, natural antioxidant capacity in patients with WD. We propose to undertake studies aimed to evaluate the usefulness of antioxidants as well as selenium as a supplemental therapy in WD.

  8. Glutamate availability is important in intramuscular amino acid metabolism and TCA cycle intermediates but does not affect peak oxidative metabolism.

    PubMed

    Mourtzakis, M; Graham, T E; González-Alonso, J; Saltin, B

    2008-08-01

    Muscle glutamate is central to reactions producing 2-oxoglutarate, a tricarboxylic acid (TCA) cycle intermediate that essentially expands the TCA cycle intermediate pool during exercise. Paradoxically, muscle glutamate drops approximately 40-80% with the onset of exercise and 2-oxoglutarate declines in early exercise. To investigate the physiological relationship between glutamate, oxidative metabolism, and TCA cycle intermediates (i.e., fumarate, malate, 2-oxoglutarate), healthy subjects trained (T) the quadriceps of one thigh on the single-legged knee extensor ergometer (1 h/day at 70% maximum workload for 5 days/wk), while their contralateral quadriceps remained untrained (UT). After 5 wk of training, peak oxygen consumption (VO2peak) in the T thigh was greater than that in the UT thigh (P<0.05); VO2peak was not different between the T and UT thighs with glutamate infusion. Peak exercise under control conditions revealed a greater glutamate uptake in the T thigh compared with rest (7.3+/-3.7 vs. 1.0+/-0.1 micromol.min(-1).kg wet wt(-1), P<0.05) without increase in TCA cycle intermediates. In the UT thigh, peak exercise (vs. rest) induced an increase in fumarate (0.33+/-0.07 vs. 0.02+/-0.01 mmol/kg dry wt (dw), P<0.05) and malate (2.2+/-0.4 vs. 0.5+/-0.03 mmol/kg dw, P<0.05) and a decrease in 2-oxoglutarate (12.2+/-1.6 vs. 32.4+/-6.8 micromol/kg dw, P<0.05). Overall, glutamate infusion increased arterial glutamate (P<0.05) and maintained this increase. Glutamate infusion coincided with elevated fumarate and malate (P<0.05) and decreased 2-oxoglutarate (P<0.05) at peak exercise relative to rest in the T thigh; there were no further changes in the UT thigh. Although glutamate may have a role in the expansion of the TCA cycle, glutamate and TCA cycle intermediates do not directly affect VO2peak in either trained or untrained muscle.

  9. Factors affecting treatment outcomes in drug-resistant tuberculosis cases in the Northern Cape, South Africa.

    PubMed

    Elliott, E; Draper, H R; Baitsiwe, P; Claassens, M M

    2014-09-21

    The Northern Cape Province has low cure rates (21%) for multidrug-resistant tuberculosis (TB). We audited the programme to identify factors affecting treatment outcomes. Cases admitted to two drug-resistant TB units from 2007 to 2009 had data extracted from clinical folders. Unfavourable treatment outcomes were found in 58% of the 272 cases. A multivariable regression analysis found that male sex was associated with unfavourable outcome (P = 0.009). Weight at diagnosis (P < 0.001) and oral drug adherence (P < 0.001) were also associated with an unfavourable outcome; however, injectable drug adherence was not (P = 0.395). Positive baseline smear and human immunodeficiency virus positive status were not associated with unfavourable outcome. Shorter, more patient-friendly regimens may go a long way to improving adherence and outcomes.

  10. In Vitro Evaluation of the Effects of Eurycoma longifolia Extract on CYP-Mediated Drug Metabolism

    PubMed Central

    Han, Young Min; Kim, In Sook; Rehman, Shaheed Ur; Choe, Kevin; Yoo, Hye Hyun

    2015-01-01

    Eurycoma longifolia (Simaroubaceae) is a popular folk medicine that has traditionally been used in Southeast Asia as an antimalarial, aphrodisiac, antidiabetic, and antimicrobial and in antipyretic remedies. This study evaluates the effects of Eurycoma longifolia extract on cytochrome P450 (CYP) enzyme-mediated drug metabolism to predict the potential for herb-drug interactions. Methanolic extract of E. longifolia root was tested at concentrations of 1, 3, 10, 30, 100, 300, and 1000 µg/mL in human liver microsomes or individual recombinant CYP isozymes. The CYP inhibitory activity was measured using the cocktail probe assay based on liquid chromatography-tandem mass spectrometry. E. longifolia showed weak, concentration-dependent inhibition of CYP1A2, CYP2A6, and CYP2C19. The inhibitory effects on these CYP isozymes were further tested using individual recombinant CYP isozymes, showing IC50 values of 324.9, 797.1, and 562.9 μg/mL, respectively. In conclusion, E. longifolia slightly inhibited the metabolic activities of CYP1A2, CYP2A6, and CYP2C19 but this issue requires careful attention in taking herbal medicines or dietary supplements containing E. longifolia extracts. PMID:26240600

  11. Mammalian flavin-containing monooxygenases: structure/function, genetic polymorphisms and role in drug metabolism

    PubMed Central

    Krueger, Sharon K.; Williams, David E.

    2005-01-01

    Flavin-containing monooxygenase (FMO) oxygenates drugs and xenobiotics containing a “soft-nucleophile”, usually nitrogen or sulfur. FMO, like cytochrome P450 (CYP), is a monooxygenase, utilizing the reducing equivalents of NADPH to reduce 1 atom of molecular oxygen to water, while the other atom is used to oxidize the substrate. FMO and CYP also exhibit similar tissue and cellular location, molecular weight, substrate specificity, and exist as multiple enzymes under developmental control. The human FMO functional gene family is much smaller (5 families each with a single member) than CYP. FMO does not require a reductase to transfer electrons from NADPH and the catalytic cycle of the 2 monooxygenases is strikingly different. Another distinction is the lack of induction of FMOs by xenobiotics. In general, CYP is the major contributor to oxidative xenobiotic metabolism. However, FMO activity may be of significance in a number of cases and should not be overlooked. FMO and CYP have overlapping substrate specificities, but often yield distinct metabolites with potentially significant toxicological/pharmacological consequences. The physiological function(s) of FMO are poorly understood. Three of the 5 expressed human FMO genes, FMO1, FMO2 and FMO3, exhibit genetic polymorphisms. The most studied of these is FMO3 (adult human liver) in which mutant alleles contribute to the disease known as trimethylaminuria. The consequences of these FMO genetic polymorphisms in drug metabolism and human health are areas of research requiring further exploration. PMID:15922018

  12. Factors Affecting the Timing of Signal Detection of Adverse Drug Reactions.

    PubMed

    Hashiguchi, Masayuki; Imai, Shungo; Uehara, Keiko; Maruyama, Junya; Shimizu, Mikiko; Mochizuki, Mayumi

    2015-01-01

    We investigated factors affecting the timing of signal detection by comparing variations in reporting time of known and unknown ADRs after initial drug release in the USA. Data on adverse event reactions (AERs) submitted to U.S. FDA was used. Six ADRs associated with 6 drugs (rosuvastatin, aripiprazole, teriparatide, telithromycin, exenatide, varenicline) were investigated: Changes in the proportional reporting ratio, reporting odds ratio, and information component as indexes of signal detection were followed every 3 months after each drugs release, and the time for detection of signals was investigated. The time for the detection of signal to be detected after drug release in the USA was 2-10 months for known ADRs and 19-44 months for unknown ones. The median lag time for known and unknown ADRs was 99.0-122.5 days and 185.5-306.0 days, respectively. When the FDA released advisory information on rare but potentially serious health risks of an unknown ADR, the time lag to report from the onset of ADRs to the FDA was shorter. This study suggested that one factor affecting signal detection time is whether an ADR was known or unknown at release. PMID:26641634

  13. Fenofibrate Suppresses Oral Tumorigenesis via Reprogramming Metabolic Processes: Potential Drug Repurposing for Oral Cancer.

    PubMed

    Jan, Chia-Ing; Tsai, Ming-Hsui; Chiu, Chang-Fang; Huang, Yi-Ping; Liu, Chia Jen; Chang, Nai Wen

    2016-01-01

    One anticancer strategy suggests targeting mitochondrial metabolism to trigger cell death through slowing down energy production from the Warburg effect. Fenofibrate is a clinical lipid-lowering agent and an effective anticancer drug. In the present study, we demonstrate that fenofibrate provided novel mechanisms for delaying oral tumor development via the reprogramming of metabolic processes. Fenofibrate induced cytotoxicity by decreasing oxygen consumption rate (OCR) that was accompanied with increasing extracellular acidification rate (ECAR) and reducing ATP content. Moreover, fenofibrate caused changes in the protein expressions of hexokinase II (HK II), pyruvate kinase, pyruvate dehydrogenase, and voltage-dependent anion channel (VDAC), which are associated with the Warburg effect. In addition, fenofibrate reprogrammed the metabolic pathway by interrupting the binding of HK II to VDAC. In an oral cancer mouse model, fenofibrate exhibited both preventive and therapeutic efficacy on oral tumorigenesis. Fenofibrate administration suppressed the incidence rate of tongue lesions, reduced the tumor sizes, decreased the tumor multiplicity, and decreased the immunoreactivities of VDAC and mTOR. The molecular mechanisms involved in fenofibrate's ability to delay tumor development included the down-regulation of mTOR activity via TSC1/2-dependent signaling through activation of AMPK and inactivation of Akt, or via a TSC1/2-independent pathway through direct suppression of raptor. Our findings provide a molecular rationale whereby fenofibrate exerts anticancer and additional beneficial effects for the treatment of oral cancer patients. PMID:27313493

  14. Fenofibrate Suppresses Oral Tumorigenesis via Reprogramming Metabolic Processes: Potential Drug Repurposing for Oral Cancer

    PubMed Central

    Jan, Chia-Ing; Tsai, Ming-Hsui; Chiu, Chang-Fang; Huang, Yi-Ping; Liu, Chia Jen; Chang, Nai Wen

    2016-01-01

    One anticancer strategy suggests targeting mitochondrial metabolism to trigger cell death through slowing down energy production from the Warburg effect. Fenofibrate is a clinical lipid-lowering agent and an effective anticancer drug. In the present study, we demonstrate that fenofibrate provided novel mechanisms for delaying oral tumor development via the reprogramming of metabolic processes. Fenofibrate induced cytotoxicity by decreasing oxygen consumption rate (OCR) that was accompanied with increasing extracellular acidification rate (ECAR) and reducing ATP content. Moreover, fenofibrate caused changes in the protein expressions of hexokinase II (HK II), pyruvate kinase, pyruvate dehydrogenase, and voltage-dependent anion channel (VDAC), which are associated with the Warburg effect. In addition, fenofibrate reprogrammed the metabolic pathway by interrupting the binding of HK II to VDAC. In an oral cancer mouse model, fenofibrate exhibited both preventive and therapeutic efficacy on oral tumorigenesis. Fenofibrate administration suppressed the incidence rate of tongue lesions, reduced the tumor sizes, decreased the tumor multiplicity, and decreased the immunoreactivities of VDAC and mTOR. The molecular mechanisms involved in fenofibrate's ability to delay tumor development included the down-regulation of mTOR activity via TSC1/2-dependent signaling through activation of AMPK and inactivation of Akt, or via a TSC1/2-independent pathway through direct suppression of raptor. Our findings provide a molecular rationale whereby fenofibrate exerts anticancer and additional beneficial effects for the treatment of oral cancer patients. PMID:27313493

  15. STAT3-Mediated Metabolic Reprograming in Cellular Transformation and Implications for Drug Resistance

    PubMed Central

    Poli, Valeria; Camporeale, Annalisa

    2015-01-01

    Signal transducer and activator of transcription (STAT)3 mediates the signaling downstream of cytokine and growth factor receptors, regulating the expression of target genes. It is constitutively phosphorylated on tyrosine (Y-P) in many tumors, where its transcriptional activity can induce a metabolic switch toward aerobic glycolysis and down-regulate mitochondrial activity, a prominent metabolic feature of most cancer cells, correlating with reduced production of ROS, delayed senescence, and protection from apoptosis. STAT3 can, however, also localize to mitochondria, where its serine-phosphorylated (S-P) form preserves mitochondrial oxidative phosphorylation and controls the opening of the mitochondrial permeability transition pore, also promoting survival and resistance to apoptosis in response to specific signals/oncogenes such as RAS. Thus, downstream of different signals, both nuclear, Y-P STAT3, and mitochondrial, S-P STAT3, can act by promoting cell survival and reducing ROS production. Here, we discuss these properties in the light of potential connections between STAT3-driven alterations of mitochondrial metabolism and the development of drug resistance in cancer patients. PMID:26106584

  16. Diet affects resting, but not basal metabolic rate of normothermic Siberian hamsters acclimated to winter.

    PubMed

    Gutowski, Jakub P; Wojciechowski, Michał S; Jefimow, Małgorzata

    2011-12-01

    We examined the effect of different dietary supplements on seasonal changes in body mass (m(b)), metabolic rate (MR) and nonshivering thermogenesis (NST) capacity in normothermic Siberian hamsters housed under semi-natural conditions. Once a week standard hamster food was supplemented with either sunflower and flax seeds, rich in polyunsaturated fatty acids (FA), or mealworms, rich in saturated and monounsaturated FA. We found that neither of these dietary supplements affected the hamsters' normal winter decrease in m(b) and fat content nor their basal MR or NST capacity. NST capacity of summer-acclimated hamsters was lower than that of winter-acclimated ones. The composition of total body fat reflected the fat composition of the dietary supplements. Resting MR below the lower critical temperature of the hamsters, and their total serum cholesterol concentration were lower in hamsters fed a diet supplemented with mealworms than in hamsters fed a diet supplemented with seeds. These results indicate that in mealworm-fed hamsters energy expenditure in the cold is lower than in animals eating a seed-supplemented diet, and that the degree of FA unsaturation of diet affects energetics of heterotherms, not only during torpor, but also during normothermy.

  17. Effect of chronic stress on behavior and cerebral oxidative metabolism in rats with high or low positive affect.

    PubMed

    Mällo, T; Matrov, D; Kõiv, K; Harro, J

    2009-12-15

    The 50 kHz ultrasonic vocalizations (USVs) in rats have been associated with positive affect and rewarding experience. We have previously reported that stable inter-individual differences exist in the expression of these USVs (chirps). We have examined the effect of four weeks of chronic variable stress on cerebral oxidative metabolism, and depression and anxiety related behavior in male and female high (HC) and low (LC) chirping rats. Significant differences in regional oxidative metabolic activity as measured by cytochrome c oxidase (COX) histochemistry were found between male and female rats: Females had lower oxidative metabolism in several brainstem areas such as dorsal and median raphe and pontine nucleus, some cortical areas, and reward-related forebrain regions such as striatum and nucleus accumbens, but higher oxidative metabolism in amygdala and related limbic regions. Chronic stress increased oxidative metabolism in several depression-related brain regions in male but not female LC-rats such as amygdala, hippocampus and anterior thalamus. No systematic behavioral effect of stress was evident in females. In LC males, stress elicited increased levels of 22-kHz USVs, earlier and more stable reduction of weight gain, persistently lower sucrose intake and preference, and higher levels of immobility in the forced swimming test. These behavioral changes, accompanied by increased oxidative metabolism in limbic brain regions, indicate greater vulnerability to stress of male LC-rats, and suggest that in males low inherent positive affectivity predisposes to anxiety and affective disorders.

  18. Analysis of drug metabolism activities in a miniaturized liver cell bioreactor for use in pharmacological studies.

    PubMed

    Hoffmann, Stefan A; Müller-Vieira, Ursula; Biemel, Klaus; Knobeloch, Daniel; Heydel, Sandra; Lübberstedt, Marc; Nüssler, Andreas K; Andersson, Tommy B; Gerlach, Jörg C; Zeilinger, Katrin

    2012-12-01

    Based on a hollow fiber perfusion technology with internal oxygenation, a miniaturized bioreactor with a volume of 0.5 mL for in vitro studies was recently developed. Here, the suitability of this novel culture system for pharmacological studies was investigated, focusing on the model drug diclofenac. Primary human liver cells were cultivated in bioreactors and in conventional monolayer cultures in parallel over 10 days. From day 3 on, diclofenac was continuously applied at a therapeutic concentration (6.4 µM) for analysis of its metabolism. In addition, the activity and gene expression of the cytochrome P450 (CYP) isoforms CYP1A2, CYP2B6, CYP2C9, CYP2D6, and CYP3A4 were assessed. Diclofenac was metabolized in bioreactor cultures with an initial conversion rate of 230 ± 57 pmol/h/10(6) cells followed by a period of stable conversion of about 100 pmol/h/10(6) cells. All CYP activities tested were maintained until day 10 of bioreactor culture. The expression of corresponding mRNAs correlated well with the degree of preservation. Immunohistochemical characterization showed the formation of neo-tissue with expression of CYP2C9 and CYP3A4 and the drug transporters breast cancer resistance protein (BCRP) and multidrug resistance protein 2 (MRP2) in the bioreactor. In contrast, monolayer cultures showed a rapid decline of diclofenac conversion and cells had largely lost activity and mRNA expression of the assessed CYP isoforms at the end of the culture period. In conclusion, diclofenac metabolism, CYP activities and gene expression levels were considerably more stable in bioreactor cultures, making the novel bioreactor a useful tool for pharmacological or toxicological investigations requiring a highly physiological in vitro representation of the liver.

  19. Dietary regulation of mouse intestinal P450 expression and drug metabolism.

    PubMed

    Zhang, Peng; Jia, Kunzhi; Fang, Cheng; Zhou, Xin; Ding, Xinxin; Zhang, Qing-Yu

    2013-02-01

    The study was originally designed to test the hypothesis that the compensatory increase in intestinal P450 (cytochrome P450) expression in the intestinal epithelium-specific P450 reductase (CPR) knockout (IE-Cpr-null) mice was attributable to decreased metabolism of putative P450 inducers present in the diet. Thus, we determined the impact of a dietary change from regular rodent chow to a synthetic diet devoid of phytochemicals on the expression of P450 enzymes in the small intestine (SI) and liver of wild-type (WT) and IE-Cpr-null mice. The dietary change diminished expression of CYP1A, 2B, 2C, and 3A in SI and CYP2B, 2C, and 3A in liver of both WT and IE-Cpr-null mice. However, the compensatory increase in SI P450 expression still occurred in IE-Cpr-null, compared with WT, mice, on the synthetic diet. The diet change-induced decrease in P450 expression was accompanied by decreases in microsomal midazolam-hydroxylase activity in vitro and first-pass clearance of midazolam in vivo in WT mice. Further studies showed that the dietary change, but not Cpr deletion, caused large decreases in bile acid (BA) levels in plasma, liver, SI, and intestinal content and that treatment of WT mice on the synthetic diet with GW4064, a farnesoid-X-receptor agonist, restored the levels of CYP3A expression in both liver and SI to those seen in mice fed with regular chow. Taken together, these results highlight the vital role of diet in maintaining adequate expression of major drug-metabolizing P450s and their associated drug-metabolizing activities in the digestive tract and suggest potential involvement of BA signaling in the regulatory mechanisms.

  20. Concentration dependent effects of tobacco particulates from different types of cigarettes on expression of drug metabolizing proteins, and benzo(a)pyrene metabolism in primary normal human oral epithelial cells

    PubMed Central

    Sacks, Peter G.; Zhao, Zhong-Lin; Kosinska, Wieslawa; Fleisher, Kenneth E.; Gordon, Terry; Guttenplan, Joseph B.

    2011-01-01

    The ability of tobacco smoke (TS) to modulate phase I and II enzymes and affect metabolism of tobacco carcinogens is likely an important factor in its carcinogenicity. For the first time several types of TS particulates (TSP) were compared in different primary cultured human oral epithelial cells (NOE) for their abilities to affect metabolism of the tobacco carcinogen, (BaP) to genotoxic products, and expression of drug metabolizing enzymes. TSP from, reference filtered (2RF4), mentholated (MS), reference unfiltered, (IR3), ultra low tar (UL), and cigarettes that primarily heat tobacco (ECL) were tested. Cells pretreated with TSP concentrations of 0.2 – 10 µg/ml generally showed increased rates of BaP metabolism; those treated with TSP concentrations above 10 µg/ml showed decreased rates. Effects of TSPs were similar when expressed on a weight basis. Weights of TSP/cigarette varied in the order: MS ≈ IR3 > 2RF4 > ECL > UL. All TSPs induced the phase I proteins, cytochrome P450 1A1 (CYP1A1) and 1B1 (CYP1B1), phase II proteins, NAD(P)H dehydrogenase quinone 1 (NQO1), and microsomal glutathione S-transferase 1 (MGST1), and additionally, hydroxysteroid (17-beta) dehydrogenase 2 (HSD17B2), as assessed by qRT-PCR. The pattern of gene induction at probable physiological levels favored activation over detoxification. PMID:21722697

  1. Mechanistic adaptability of cancer cells strongly affects anti-migratory drug efficacy.

    PubMed

    Sun, Wei; Lim, Chwee Teck; Kurniawan, Nicholas Agung

    2014-10-01

    Cancer metastasis involves the dissemination of cancer cells from the primary tumour site and is responsible for the majority of solid tumour-related mortality. Screening of anti-metastasis drugs often includes functional assays that examine cancer cell invasion inside a three-dimensional hydrogel that mimics the extracellular matrix (ECM). Here, we built a mechanically tuneable collagen hydrogel model to recapitulate cancer spreading into heterogeneous tumour stroma and monitored the three-dimensional invasion of highly malignant breast cancer cells, MDA-MB-231. Migration assays were carried out in the presence and the absence of drugs affecting four typical molecular mechanisms involved in cell migration, as well as under five ECMs with different biophysical properties. Strikingly, the effects of the drugs were observed to vary strongly with matrix mechanics and microarchitecture, despite the little dependence of the inherent cancer cell migration on the ECM condition. Specifically, cytoskeletal contractility-targeting drugs reduced migration speed in sparse gels, whereas migration in dense gels was retarded effectively by inhibiting proteolysis. The results corroborate the ability of cancer cells to switch their multiple invasion mechanisms depending on ECM condition, thus suggesting the importance of factoring in the biophysical properties of the ECM in anti-metastasis drug screenings.

  2. Characterization of the activities of actin-affecting drugs on tumor cell migration

    SciTech Connect

    Hayot, Caroline; Debeir, Olivier; Ham, Philippe van; Damme, Marc van; Kiss, Robert; Decaestecker, Christine . E-mail: cdecaes@ulb.ac.be

    2006-02-15

    Metastases kill 90% of cancer patients. It is thus a major challenge in cancer therapy to inhibit the spreading of tumor cells from primary tumor sites to those particular organs where metastases are likely to occur. Whereas the actin cytoskeleton is a key component involved in cell migration, agents targeting actin dynamics have been relatively poorly investigated. Consequently, valuable in vitro pharmacological tools are needed to selectively identify this type of agent. In response to the absence of any standardized process, the present work aims to develop a multi-assay strategy for screening actin-affecting drugs with anti-migratory potentials. To validate our approach, we used two cancer cell lines (MCF7 and A549) and three actin-affecting drugs (cytochalasin D, latrunculin A, and jasplakinolide). We quantified the effects of these drugs on the kinetics of actin polymerization in tubes (by means of spectrofluorimetry) and on the dynamics of actin cytoskeletons within whole cells (by means of fluorescence microscopy). Using quantitative videomicroscopy, we investigated the actual effects of the drugs on cell motility. Finally, the combined drug effects on cell motility and cell growth were evaluated by means of a scratch-wound assay. While our results showed concordant drug-induced effects on actin polymerization occurring in vitro in test tubes and within whole cells, the whole cell assay appeared more sensitive than the tube assay. The inhibition of actin polymerization induced by cytochalasin D was paralleled by a decrease in cell motility for both cell types. In the case of jasplakinolide, which induces actin polymerization, while it significantly enhanced the locomotion of the A549 cells, it significantly inhibited that of the MCF-7 ones. All these effects were confirmed by means of the scratch-wound assay except of the jasplakinolide-induced effects on MCF-7 cell motility. These later seemed compensated by an additional effect occurring during wound

  3. A simple construction of electrochemical liver microsomal bioreactor for rapid drug metabolism and inhibition assays.

    PubMed

    Walgama, Charuksha; Nerimetla, Rajasekhara; Materer, Nicholas F; Schildkraut, Deniz; Elman, James F; Krishnan, Sadagopan

    2015-01-01

    In order to design a green microsomal bioreactor on suitably identified carbon electrodes, it is important to understand the direct electrochemical properties at the interfaces between various carbon electrode materials and human liver microsomes (HLM). The novelty of this work is on the investigation of directly adsorbed HLM on different carbon electrodes with the goal to develop a simple, rapid, and new bioanalytical platform of HLM useful for drug metabolism and inhibition assays. These novel biointerfaces are designed in this study by a one step adsorption of HLM directly onto polished basal plane pyrolytic graphite (BPG), edge plane pyrolytic graphite (EPG), glassy carbon (GC), or high-purity graphite (HPG) electrodes. The estimated direct electron transfer (ET) rate constant of HLM on the smooth GC surface was significantly greater than that of the other electrodes. On the other hand, the electroactive surface coverage and stability of microsomal films were greater on highly surface defective, rough EPG and HPG electrodes compared to the smooth GC and less defective hydrophobic BPG surfaces. The presence of significantly higher oxygen functionalities and flatness of the GC surface is attributed to favoring faster ET rates of the coated layer of thin HLM film compared to other electrodes. The cytochrome P450 (CYP)-specific bioactivity of the liver microsomal film on the catalytically superior, stable HPG surface was confirmed by monitoring the electrocatalytic conversion of testosterone to 6β-hydroxytestosterone and its inhibition by the CYP-specific ketoconazole inhibitor. The identification of optimal HPG and EPG electrodes to design biologically active interfaces with liver microsomes is suggested to have immense significance in the design of one-step, green bioreactors for stereoselective drug metabolite synthesis and drug metabolism and inhibition assays.

  4. Modulation of Glycosaminoglycans Affects PrPSc Metabolism but Does Not Block PrPSc Uptake

    PubMed Central

    Wolf, Hanna; Graßmann, Andrea; Bester, Romina; Hossinger, André; Möhl, Christoph; Paulsen, Lydia; Groschup, Martin H.; Schätzl, Hermann

    2015-01-01

    ABSTRACT Mammalian prions are unconventional infectious agents composed primarily of the misfolded aggregated host prion protein PrP, termed PrPSc. Prions propagate by the recruitment and conformational conversion of cellular prion protein into abnormal prion aggregates on the cell surface or along the endocytic pathway. Cellular glycosaminoglycans have been implicated as the first attachment sites for prions and cofactors for cellular prion replication. Glycosaminoglycan mimetics and obstruction of glycosaminoglycan sulfation affect prion replication, but the inhibitory effects on different strains and different stages of the cell infection have not been thoroughly addressed. We examined the effects of a glycosaminoglycan mimetic and undersulfation on cellular prion protein metabolism, prion uptake, and the establishment of productive infections in L929 cells by two mouse-adapted prion strains. Surprisingly, both treatments reduced endogenous sulfated glycosaminoglycans but had divergent effects on cellular PrP levels. Chemical or genetic manipulation of glycosaminoglycans did not prevent PrPSc uptake, arguing against their roles as essential prion attachment sites. However, both treatments effectively antagonized de novo prion infection independently of the prion strain and reduced PrPSc formation in chronically infected cells. Our results demonstrate that sulfated glycosaminoglycans are dispensable for prion internalization but play a pivotal role in persistently maintained PrPSc formation independent of the prion strain. IMPORTANCE Recently, glycosaminoglycans (GAGs) became the focus of neurodegenerative disease research as general attachment sites for cell invasion by pathogenic protein aggregates. GAGs influence amyloid formation in vitro. GAGs are also found in intra- and extracellular amyloid deposits. In light of the essential role GAGs play in proteinopathies, understanding the effects of GAGs on protein aggregation and aggregate dissemination is crucial

  5. Decreased Zinc Availability Affects Glutathione Metabolism in Neuronal Cells and in the Developing Brain

    PubMed Central

    Omata, Yo; Salvador, Gabriela A.; Oteiza, Patricia I.

    2013-01-01

    A deficit in zinc (Zn) availability can increase cell oxidant production, affect the antioxidant defense system, and trigger oxidant-sensitive signals in neuronal cells. This work tested the hypothesis that a decreased Zn availability can affect glutathione (GSH) metabolism in the developing rat brain and in neuronal cells in culture, as well as the capacity of human neuroblastoma IMR-32 cells to upregulate GSH when challenged with dopamine (DA). GSH levels were low in the brain of gestation day 19 (GD19) fetuses from dams fed marginal Zn diets throughout gestation and in Zn-deficient IMR-32 cells. γ-Glutamylcysteine synthetase (GCL), the first enzyme in the GSH synthetic pathway, was altered by Zn deficiency (ZD). The protein and mRNA levels of the GCL modifier (GCLM) and catalytic (GCLC) subunits were lower in the Zn-deficient GD19 fetal brain and in IMR-32 cells compared with controls. The nuclear translocation of transcription factor nuclear factor (erythroid-derived 2)-like 2, which controls GCL transcription, was impaired by ZD. Posttranslationally, the caspase-3-dependent GCLC cleavage was high in Zn-deficient IMR-32 cells. Cells challenged with DA showed an increase in GCLM and GCLC protein and mRNA levels and a consequent increase in GSH concentration. Although Zn-deficient cells partially upregulated GCL subunits after exposure to DA, GSH content remained low. In summary, results show that a low Zn availability affects the GSH synthetic pathway in neuronal cells and fetal brain both at transcriptional and posttranslational levels. This can in part underlie the GSH depletion associated with ZD and the high sensitivity of Zn-deficient neurons to pro-oxidative stressors. PMID:23377617

  6. Effect of various diets on the expression of phase-I drug-metabolizing enzymes in livers of mice.

    PubMed

    Guo, Ying; Cui, Julia Yue; Lu, Hong; Klaassen, Curtis D

    2015-01-01

    1. Previous studies have shown that diets can alter the metabolism of drugs; however, it is difficult to compare the effects of multiple diets on drug metabolism among different experimental settings. Phase-I-related genes play a major role in the biotransformation of pro-drugs and drugs. 2. In the current study, effects of nine diets on the mRNA expression of phase-I drug metabolizing enzymes in livers of mice were simultaneously investigated. Compared to the AIN-93M purified diet (control), 73 of the 132 critical phase-I drug-metabolizing genes were differentially regulated by at least one diet. Diet restriction produced the largest number of changed genes (51), followed by the atherogenic diet (27), high-fat diet (25), standard rodent chow (21), western diet (20), high-fructose diet (5), EFA deficient diet (3) and low n-3 FA diet (1). The mRNAs of the Fmo family changed most, followed by Cyp2b and 4a subfamilies, as well as Por (from 1121- to 21-fold increase of theses mRNAs). There were 59 genes not altered by any of these diets. 3. The present results may improve the interpretation of studies with mice and aid in determining effective and safe doses for individuals with different nutritional diets.

  7. Metabolic rate, latitude and thermal stability of roosts, but not phylogeny, affect rewarming rates of bats.

    PubMed

    Menzies, Allyson K; Webber, Quinn M R; Baloun, Dylan E; McGuire, Liam P; Muise, Kristina A; Coté, Damien; Tinkler, Samantha; Willis, Craig K R

    2016-10-01

    Torpor is an adaptation that allows many endotherms to save energy by abandoning the energetic cost of maintaining elevated body temperatures. Although torpor reduces energy consumption, the metabolic heat production required to arouse from torpor is energetically expensive and can impact the overall cost of torpor. The rate at which rewarming occurs can impact the cost of arousal, therefore, factors influencing rewarming rates of heterothermic endotherms could have influenced the evolution of rewarming rates and overall energetic costs of arousal from torpor. Bats are a useful taxon for studies of ecological and behavioral correlates of rewarming rate because of the widespread expression of heterothermy and ecological diversity across the >1200 known species. We used a comparative analysis of 45 bat species to test the hypothesis that ecological, behavioral, and physiological factors affect rewarming rates. We used basal metabolic rate (BMR) as an index of thermogenic capacity, and local climate (i.e., latitude of geographic range), roost stability and maximum colony size as ecological and behavioral predictors of rewarming rate. After controlling for phylogeny, high BMR was associated with rapid rewarming while species that live at higher absolute latitudes and in less thermally stable roosts also rewarmed most rapidly. These patterns suggests that some bat species rely on passive rewarming and social thermoregulation to reduce costs of rewarming, while others might rely on thermogenic capacity to maintain rapid rewarming rates in order to reduce energetic costs of arousal. Our results highlight species-specific traits associated with maintaining positive energy balance in a wide range of climates, while also providing insight into possible mechanisms underlying the evolution of heterothermy in endotherms.

  8. Metabolic rate, latitude and thermal stability of roosts, but not phylogeny, affect rewarming rates of bats.

    PubMed

    Menzies, Allyson K; Webber, Quinn M R; Baloun, Dylan E; McGuire, Liam P; Muise, Kristina A; Coté, Damien; Tinkler, Samantha; Willis, Craig K R

    2016-10-01

    Torpor is an adaptation that allows many endotherms to save energy by abandoning the energetic cost of maintaining elevated body temperatures. Although torpor reduces energy consumption, the metabolic heat production required to arouse from torpor is energetically expensive and can impact the overall cost of torpor. The rate at which rewarming occurs can impact the cost of arousal, therefore, factors influencing rewarming rates of heterothermic endotherms could have influenced the evolution of rewarming rates and overall energetic costs of arousal from torpor. Bats are a useful taxon for studies of ecological and behavioral correlates of rewarming rate because of the widespread expression of heterothermy and ecological diversity across the >1200 known species. We used a comparative analysis of 45 bat species to test the hypothesis that ecological, behavioral, and physiological factors affect rewarming rates. We used basal metabolic rate (BMR) as an index of thermogenic capacity, and local climate (i.e., latitude of geographic range), roost stability and maximum colony size as ecological and behavioral predictors of rewarming rate. After controlling for phylogeny, high BMR was associated with rapid rewarming while species that live at higher absolute latitudes and in less thermally stable roosts also rewarmed most rapidly. These patterns suggests that some bat species rely on passive rewarming and social thermoregulation to reduce costs of rewarming, while others might rely on thermogenic capacity to maintain rapid rewarming rates in order to reduce energetic costs of arousal. Our results highlight species-specific traits associated with maintaining positive energy balance in a wide range of climates, while also providing insight into possible mechanisms underlying the evolution of heterothermy in endotherms. PMID:27317837

  9. Altered cobalamin metabolism in Escherichia coli btuR mutants affects btuB gene regulation.

    PubMed Central

    Lundrigan, M D; Kadner, R J

    1989-01-01

    Synthesis of the Escherichia coli outer membrane protein BtuB, which mediates the binding and transport of vitamin B12, is repressed when cells are grown in the presence of vitamin B12. Expression of btuB-lacZ fusions was also found to be repressed, and selection for constitutive production of beta-galactosidase in the presence of vitamin B12 yielded mutations at btuR. The btuR locus, at 27.9 min on the chromosome map, was isolated on a 952-base-pair EcoRV fragment, and its nucleotide sequence was determined. The BtuR protein was identified in maxicells as a 22,000-dalton polypeptide, as predicted from the nucleotide sequence. Strains mutant at btuR had negligible pools of adenosylcobalamin but did convert vitamin B12 into other derivatives. Although btuB expression in a btuR strain could not be repressed by cyano- or methylcobalamin, it was repressed by adenosylcobalamin. Growth on ethanolamine as the sole nitrogen source requires adenosylcobalamin. btuR mutants grew on ethanolamine but were affected in the length of the lag period before initiation of growth, which suggested that an alternative route for adenosylcobalamin synthesis might exist. No mutations were found that conferred constitutive btuB expression in the presence of adenosylcobalamin. Other genes near btuR may also be involved in cobalamin metabolism, as suggested from the complementation behavior of strains generated by excision of the Tn10 element in btuR. These results indicated that the btuR product is involved in the metabolism of adenosylcobalamin and that this cofactor, or some derivative, controls btuB expression. Images PMID:2644187

  10. Multiple dietary supplements do not affect metabolic and cardio-vascular health.

    PubMed

    Soare, Andreea; Weiss, Edward P; Holloszy, John O; Fontana, Luigi

    2014-02-01

    Dietary supplements are widely used for health purposes. However, little is known about the metabolic and cardiovascular effects of combinations of popular over-the-counter supplements, each of which has been shown to have anti-oxidant, anti-inflammatory and pro-longevity properties in cell culture or animal studies. This study was a 6-month randomized, single-blind controlled trial, in which 56 non-obese (BMI 21.0-29.9 kg/m(2)) men and women, aged 38 to 55 yr, were assigned to a dietary supplement (SUP) group or control (CON) group, with a 6-month follow-up. The SUP group took 10 dietary supplements each day (100 mg of resveratrol, a complex of 800 mg each of green, black, and white tea extract, 250 mg of pomegranate extract, 650 mg of quercetin, 500 mg of acetyl-l-carnitine, 600 mg of lipoic acid, 900 mg of curcumin, 1 g of sesamin, 1.7 g of cinnamon bark extract, and 1.0 g fish oil). Both the SUP and CON groups took a daily multivitamin/mineral supplement. The main outcome measures were arterial stiffness, endothelial function, biomarkers of inflammation and oxidative stress, and cardiometabolic risk factors. Twenty-four weeks of daily supplementation with 10 dietary supplements did not affect arterial stiffness or endothelial function in nonobese individuals. These compounds also did not alter body fat measured by DEXA, blood pressure, plasma lipids, glucose, insulin, IGF-1, and markers of inflammation and oxidative stress. In summary, supplementation with a combination of popular dietary supplements has no cardiovascular or metabolic effects in non-obese relatively healthy individuals.

  11. Environmentally Relevant Dose of Bisphenol A Does Not Affect Lipid Metabolism and Has No Synergetic or Antagonistic Effects on Genistein’s Beneficial Roles on Lipid Metabolism

    PubMed Central

    Fan, Ying; Li, Hongyu; Zhao, Nana; Yang, Huiqin; Ye, Xiaolei; He, Dongliang; Yang, Hui; Jin, Xin; Tian, Chong; Ying, Chenjiang

    2016-01-01

    Both bisphenol A (BPA, an endocrine disrupting chemicals) and genistein (a phytoestrogen mainly derived from leguminosae) are able to bind to estrogen receptors, but they are considered to have different effects on metabolic syndrome, surprisingly. We here investigate the effects of an environmentally relevant dose of BPA alone and the combined effects with genistein on lipid metabolism in rats. Eight groups of adult male Wistar rats, fed with either standard chow diet or high-fat diet, were treated with BPA (50μg/kg/day), genistein (10mg/kg/day), and BPA plus genistein for 35 weeks, respectively. Metabolic parameters in serum and liver were determined; the hematoxylin/eosin and oil Red O staining were used to observe liver histologically; gene expressions related to hepatic lipid metabolism were analyzed by Real-time PCR; protein expressions of PPARγ, PPARα and LC3 in liver were analyzed by western blotting. No difference of body weight gain, total energy intake, liver weight/body weight or body fat percentage in both STD- and HFD-fed sub-groups was observed after treatment with BPA, genistein, or BPA plus genistein (P>0.05). Genistein alleviated lipid metabolism disorder and decreased the mRNA and protein expression of PPARγ (P<0.05), and increased the protein expression of LC3II (P<0.05) in liver of HFD-fed rats. However, BPA treatment had no effect on lipid metabolism in rats alone (P>0.05) or combined with genistein. Our findings suggest that long-term environmentally relevant dose of BPA did not affect lipid metabolism, and had no synergetic or antagonistic roles on genistein’s beneficial function on hepatic lipid metabolism. PMID:27171397

  12. Environmentally Relevant Dose of Bisphenol A Does Not Affect Lipid Metabolism and Has No Synergetic or Antagonistic Effects on Genistein's Beneficial Roles on Lipid Metabolism.

    PubMed

    Ding, Shibin; Zuo, Xuezhi; Fan, Ying; Li, Hongyu; Zhao, Nana; Yang, Huiqin; Ye, Xiaolei; He, Dongliang; Yang, Hui; Jin, Xin; Tian, Chong; Ying, Chenjiang

    2016-01-01

    Both bisphenol A (BPA, an endocrine disrupting chemicals) and genistein (a phytoestrogen mainly derived from leguminosae) are able to bind to estrogen receptors, but they are considered to have different effects on metabolic syndrome, surprisingly. We here investigate the effects of an environmentally relevant dose of BPA alone and the combined effects with genistein on lipid metabolism in rats. Eight groups of adult male Wistar rats, fed with either standard chow diet or high-fat diet, were treated with BPA (50μg/kg/day), genistein (10mg/kg/day), and BPA plus genistein for 35 weeks, respectively. Metabolic parameters in serum and liver were determined; the hematoxylin/eosin and oil Red O staining were used to observe liver histologically; gene expressions related to hepatic lipid metabolism were analyzed by Real-time PCR; protein expressions of PPARγ, PPARα and LC3 in liver were analyzed by western blotting. No difference of body weight gain, total energy intake, liver weight/body weight or body fat percentage in both STD- and HFD-fed sub-groups was observed after treatment with BPA, genistein, or BPA plus genistein (P>0.05). Genistein alleviated lipid metabolism disorder and decreased the mRNA and protein expression of PPARγ (P<0.05), and increased the protein expression of LC3II (P<0.05) in liver of HFD-fed rats. However, BPA treatment had no effect on lipid metabolism in rats alone (P>0.05) or combined with genistein. Our findings suggest that long-term environmentally relevant dose of BPA did not affect lipid metabolism, and had no synergetic or antagonistic roles on genistein's beneficial function on hepatic lipid metabolism. PMID:27171397

  13. Tumour-selective targeting of drug metabolizing enzymes to treat metastatic cancer.

    PubMed

    Wierdl, Monika; Tsurkan, Lyudmila; Hatfield, M Jason; Potter, Philip M

    2016-10-01

    Carboxylesterases (CEs) are ubiquitous enzymes responsible for the detoxification of ester-containing xenobiotics. This hydrolysis reaction results in the formation of the corresponding carboxylic acid and alcohol. Due to their highly plastic active site, CEs can hydrolyze structurally very distinct and complex molecules. Because ester groups significantly increase the water solubility of compounds, they are frequently used in the pharmaceutical industry to make relatively insoluble compounds more bioavailable. By default, this results in CEs playing a major role in the distribution and metabolism of these esterified drugs. However, this can be exploited to selectively improve compound hydrolysis, and using specific in vivo targeting techniques can be employed to generate enhanced drug activity. Here, we seek to detail the human CEs involved in esterified molecule hydrolysis, compare and contrast these with CEs present in small mammals and describe novel methods to improve drug therapy by specific delivery of CEs to cells in vivo. Finally, we will discuss the development of such approaches for their potential application towards malignant disease.

  14. Metabolism and excretion of a new antipsychotic drug, ziprasidone, in humans.

    PubMed

    Prakash, C; Kamel, A; Gummerus, J; Wilner, K

    1997-07-01

    The pharmacokinetics, metabolism, and excretion of a new antipsychotic drug, ziprasidone, were studied in four normal male volunteers after oral administration of a single 20 mg dose of a mixture of 14C- and 3H-labeled ziprasidone. Blood, urine, and feces were collected at various intervals for determination of total radioactivity and metabolic profiles. Eleven days after the dose, 20.3 +/- 1% of the administered radioactivity was recovered in the urine and 66.3 +/- 4.8% in feces. The absorption of ziprasidone was rapid, and the C(max) for ziprasidone and metabolites occurred at 2 to 6 hr postdose. Mean peak serum concentration of unchanged drug was 45 ng/ml and a mean AUC(0-t) of 335.7 ng x hr/ml. Mean peak serum concentration of total radioactivity (average of 3H and 14C) was 91 ng-eq/ml and a mean AUC(0-t) of 724.6 ng-eq x hr/ml. On the basis of AUC(0-t) values, approximately 46% of circulating radioactivity was attributable to unchanged drug. Ziprasidone was extensively metabolized and only a small amount (<5% of the administered dose) was excreted in urine and feces as unchanged drug. Twelve metabolites in human urine and serum were identified by ion-spray LC/MS and LC/MS/MS with simultaneous monitoring of radioactivity. The major urinary metabolites were identified as oxindole-acetic acid and its glucuronide conjugate, benzisothiazole-3-yl-piperazine (BITP), BITP-sulfoxide, BITP-sulfone and its lactam, ziprasidone-sulfoxide, and sulfone similar to those identified in rats. In addition, two novel metabolic pathways (reductive cleavage and N-dearylation of the benzisothiazole ring) were identified for ziprasidone in humans. The metabolites resulted by these pathways were characterized as S-methyl-dihydroziprasidone, S-methyl-dihydro-ziprasidone sulfoxide, and 6-chloro-5-(2-piperazin-1-yl-ethyl)-1,3-dihydro-indol-2-one, respectively. Ziprasidone sulfoxide and sulfone were the major metabolites in human serum. The affinities of the sulfoxide and sulfone

  15. Antiepileptic carbamazepine drug treatment induces alteration of membrane in red blood cells: possible positive effects on metabolism and oxidative stress.

    PubMed

    Ficarra, Silvana; Misiti, Francesco; Russo, Annamaria; Carelli-Alinovi, Cristiana; Bellocco, Ersilia; Barreca, Davide; Laganà, Giuseppina; Leuzzi, Ugo; Toscano, Giovanni; Giardina, Bruno; Galtieri, Antonio; Tellone, Ester

    2013-04-01

    Carbamazepine (CBZ) is an iminostilbene derivative commonly used for treatment of neuralgic pain and bipolar affective disorders. CBZ blood levels of treated patients are within the range of micromolar concentrations and therefore, significant interactions of this drug with erythrocytes are very likely. Moreover, the lipid domains of the cell membrane are believed to be one of the sites where iminostilbene derivatives exert their effects. The present study aimed to deeply characterize CBZ effects on erythrocytes, in order to identify extra and/or cytosolic cell targets. Our results indicate that erythrocyte morphological changes promoted by the drug, may be triggered by an alteration in band 3 functionality i.e. at the level of anionic flux. In addition, from a metabolic point of view this perturbation could be considered, at least in part, as a beneficial event because it could favour the CO2 elimination. Since lipid peroxidation, superoxide and free radical scavenging activities, caspase 3 activity and hemoglobin (Hb) functionality were not modified within the CBZ treated red blood cell (RBC), band 3 protein (B3) may well be a specific membrane target for CBZ and responsible for CBZ-induced toxic effects in erythrocytes. However some beneficial effects of this drug have been evidenced; among them an increased release of ATP and nitric oxide (NO) derived metabolites from erythrocytes to lumen, leading to an increased NO pool in the vasculature. In conclusion, these results indicate that CBZ, though considered responsible for toxic effects on erythrocytes, can also exhibit effects that at least in some conditions may be seen as beneficial.

  16. Cadmium effect on microsomal drug-metabolizing enzyme activity in rat livers with respect to differences in age and sex

    SciTech Connect

    Ando, M.

    1982-04-01

    The effect of cadmium on the hepatic microsomal drug-metabolizing enzyme system was investigated. Cadmium chloride caused the conversion of cytochrome P-450 to P-420 in rat liver microsomes. The destruction of cytochrome P-450 by cadmium caused the reduction of microsomal drug-metabolizing enzyme activity and prolonged the pentobarbital sleeping time. There is a sex-related difference in the ability of cadmium to inhibit the hepatic drug metabolism in rats: male rats are more sensitive to cadmium than females. The effective period when cadmium prolonged their sleep depended upon the age of rats; older rats were more sensitive to cadmium than younger ones. The maximum increase of sleeping time depended upon the dose level of cadium, and the rate constant of the equations seems to depend upon the age of the animals.

  17. Gallic acid and gallic acid derivatives: effects on drug metabolizing enzymes.

    PubMed

    Ow, Yin-Yin; Stupans, Ieva

    2003-06-01

    Gallic acid and its structurally related compounds are found widely distributed in fruits and plants. Gallic acid, and its catechin derivatives are also present as one of the main phenolic components of both black and green tea. Esters of gallic acid have a diverse range of industrial uses, as antioxidants in food, in cosmetics and in the pharmaceutical industry. In addition, gallic acid is employed as a source material for inks, paints and colour developers. Studies utilising these compounds have found them to possess many potential therapeutic properties including anti-cancer and antimicrobial properties. In this review, studies of the effects of gallic acid, its esters, and gallic acid catechin derivatives on Phase I and Phase II enzymes are examined. Many published reports of the effects of the in vitro effects of gallic acid and its derivatives on drug metabolising enzymes concern effects directly on substrate (generally drug or mutagen) metabolism or indirectly through observed effects in Ames tests. In the case of the Ames test an antimutagenic effect may be observed through inhibition of CYP activation of indirectly acting mutagens and/or by scavenging of metabolically generated mutagenic electrophiles. There has been considerable interest in the in vivo effects of the gallate esters because of their incorporation into foodstuffs as antioxidants and in the catechin gallates with their potential role as chemoprotective agents. Principally an induction of Phase II enzymes has been observed however more recent studies using HepG2 cells and primary cultures of human hepatocytes provide evidence for the overall complexity of actions of individual components versus complex mixtures, such as those in food. Further systematic studies of mechanisms of induction and inhibition of drug metabolising enzymes by this group of compounds are warranted in the light of their distribution and consequent ingestion, current uses and suggested therapeutic potential. However, it

  18. Diet-Induced Alterations of Host Cholesterol Metabolism Are Likely To Affect the Gut Microbiota Composition in Hamsters

    PubMed Central

    Martínez, Inés; Perdicaro, Diahann J.; Brown, Andrew W.; Hammons, Susan; Carden, Trevor J.; Carr, Timothy P.; Eskridge, Kent M.

    2013-01-01

    The gastrointestinal microbiota affects the metabolism of the mammalian host and has consequences for health. However, the complexity of gut microbial communities and host metabolic pathways make functional connections difficult to unravel, especially in terms of causation. In this study, we have characterized the fecal microbiota of hamsters whose cholesterol metabolism was extensively modulated by the dietary addition of plant sterol esters (PSE). PSE intake induced dramatic shifts in the fecal microbiota, reducing several bacterial taxa within the families Coriobacteriaceae and Erysipelotrichaceae. The abundance of these taxa displayed remarkably high correlations with host cholesterol metabolites. Most importantly, the associations between several bacterial taxa with fecal and biliary cholesterol excretion showed an almost perfect fit to a sigmoidal nonlinear model of bacterial inhibition, suggesting that host cholesterol excretion can shape microbiota structure through the antibacterial action of cholesterol. In vitro experiments suggested a modest antibacterial effect of cholesterol, and especially of cholesteryl-linoleate, but not plant sterols when included in model bile micelles. The findings obtained in this study are relevant to our understanding of gut microbiota-host lipid metabolism interactions, as they provide the first evidence for a role of cholesterol excreted with the bile as a relevant host factor that modulates the gut microbiota. The findings further suggest that the connections between Coriobacteriaceae and Erysipelotrichaceae and host lipid metabolism, which have been observed in several studies, could be caused by a metabolic phenotype of the host (cholesterol excretion) affecting the gut microbiota. PMID:23124234

  19. Metabolic profiling using HPLC allows classification of drugs according to their mechanisms of action in HL-1 cardiomyocytes

    SciTech Connect

    Strigun, Alexander; Wahrheit, Judith; Beckers, Simone; Heinzle, Elmar; Noor, Fozia

    2011-04-15

    Along with hepatotoxicity, cardiotoxic side effects remain one of the major reasons for drug withdrawals and boxed warnings. Prediction methods for cardiotoxicity are insufficient. High content screening comprising of not only electrophysiological characterization but also cellular molecular alterations are expected to improve the cardiotoxicity prediction potential. Metabolomic approaches recently have become an important focus of research in pharmacological testing and prediction. In this study, the culture medium supernatants from HL-1 cardiomyocytes after exposure to drugs from different classes (analgesics, antimetabolites, anthracyclines, antihistamines, channel blockers) were analyzed to determine specific metabolic footprints in response to the tested drugs. Since most drugs influence energy metabolism in cardiac cells, the metabolite 'sub-profile' consisting of glucose, lactate, pyruvate and amino acids was considered. These metabolites were quantified using HPLC in samples after exposure of cells to test compounds of the respective drug groups. The studied drug concentrations were selected from concentration response curves for each drug. The metabolite profiles were randomly split into training/validation and test set; and then analysed using multivariate statistics (principal component analysis and discriminant analysis). Discriminant analysis resulted in clustering of drugs according to their modes of action. After cross validation and cross model validation, the underlying training data were able to predict 50%-80% of conditions to the correct classification group. We show that HPLC based characterisation of known cell culture medium components is sufficient to predict a drug's potential classification according to its mode of action.

  20. The activity of drug-metabolizing enzymes and the biotransformation of selected anthelmintics in the model tapeworm Hymenolepis diminuta.

    PubMed

    Bártíková, Hana; Vokřál, Ivan; Skálová, Lenka; Kubíček, Vladimír; Firbasová, Jana; Briestenský, David; Lamka, Jiří; Szotáková, Barbora

    2012-05-01

    The drug-metabolizing enzymes of some helminths can deactivate anthelmintics and therefore partially protect helminths against these drugs' toxic effect. The aim of our study was to assess the activity of the main drug-metabolizing enzymes and evaluate the metabolism of selected anthelmintics (albendazole, flubendazole, mebendazole) in the rat tapeworm Hymenolepis diminuta, a species often used as a model tapeworm. In vitro and ex vivo experiments were performed. Metabolites of the anthelmintics were detected and identified by HPLC with spectrofluorometric or mass-spectrometric detection. The enzymes of H. diminuta are able to reduce the carbonyl group of flubendazole, mebendazole and several other xenobiotics. Although the activity of a number of oxidation enzymes was determined, no oxidative metabolites of albendazole were detected. Regarding conjugation enzymes, a high activity of glutathione S-transferase was observed. A methyl derivative of reduced flubendazole was the only conjugation metabolite identified in ex vivo incubations of H. diminuta with anthelmintics. The results revealed that H. diminuta metabolized flubendazole and mebendazole, but not albendazole. The biotransformation pathways found in H. diminuta differ from those described in Moniezia expanza and suggest the interspecies differences in drug metabolism not only among classes of helminths, but even among tapeworms.

  1. Effects of drugs in subtoxic concentrations on the metabolic fluxes in human hepatoma cell line Hep G2

    SciTech Connect

    Niklas, Jens; Noor, Fozia; Heinzle, Elmar

    2009-11-01

    Commonly used cytotoxicity assays assess the toxicity of a compound by measuring certain parameters which directly or indirectly correlate to the viability of the cells. However, the effects of a given compound at concentrations considerably below EC{sub 50} values are usually not evaluated. These subtoxic effects are difficult to identify but may eventually cause severe and costly long term problems such as idiosyncratic hepatotoxicity. We determined the toxicity of three hepatotoxic compounds, namely amiodarone, diclofenac and tacrine on the human hepatoma cell line Hep G2 using an online kinetic respiration assay and analysed the effects of subtoxic concentrations of these drugs on the cellular metabolism by using metabolic flux analysis. Several changes in the metabolism could be detected upon exposure to subtoxic concentrations of the test compounds. Upon exposure to diclofenac and tacrine an increase in the TCA-cycle activity was observed which could be a signature of an uncoupling of the oxidative phosphorylation. The results indicate that metabolic flux analysis could serve as an invaluable novel tool for the investigation of the effects of drugs. The described methodology enables tracking the toxicity of compounds dynamically using the respiration assay in a range of concentrations and the metabolic flux analysis permits interesting insights into the changes in the central metabolism of the cell upon exposure to drugs.

  2. AMP-activated protein kinase: an emerging drug target to regulate imbalances in lipid and carbohydrate metabolism to treat cardio-metabolic diseases

    PubMed Central

    Srivastava, Rai Ajit K.; Pinkosky, Stephen L.; Filippov, Sergey; Hanselman, Jeffrey C.; Cramer, Clay T.; Newton, Roger S.

    2012-01-01

    The adenosine monophosphate-activated protein kinase (AMPK) is a metabolic sensor of energy metabolism at the cellular as well as whole-body level. It is activated by low energy status that triggers a switch from ATP-consuming anabolic pathways to ATP-producing catabolic pathways. AMPK is involved in a wide range of biological activities that normalizes lipid, glucose, and energy imbalances. These pathways are dysregulated in patients with metabolic syndrome (MetS), which represents a clustering of major cardiovascular risk factors including diabetes, lipid abnormalities, and energy imbalances. Clearly, there is an unmet medical need to find a molecule to treat alarming number of patients with MetS. AMPK, with multifaceted activities in various tissues, has emerged as an attractive drug target to manage lipid and glucose abnormalities and maintain energy homeostasis. A number of AMPK activators have been tested in preclinical models, but many of them have yet to reach to the clinic. This review focuses on the structure-function and role of AMPK in lipid, carbohydrate, and energy metabolism. The mode of action of AMPK activators, mechanism of anti-inflammatory activities, and preclinical and clinical findings as well as future prospects of AMPK as a drug target in treating cardio-metabolic disease are discussed. PMID:22798688

  3. Dietary arginine affects energy metabolism through polyamine turnover in juvenile Atlantic salmon (Salmo salar).

    PubMed

    Andersen, Synne M; Holen, Elisabeth; Aksnes, Anders; Rønnestad, Ivar; Zerrahn, Jens-Erik; Espe, Marit

    2013-12-14

    In the present study, quadruplicate groups of juvenile Atlantic salmon (Salmo salar) were fed plant protein-based diets with increasing arginine inclusions (range 28·8-37·4 g/kg DM) to investigate whether arginine supplementation affects growth and lipid accumulation through an elevated polyamine turnover. Dietary lysine was held at a constant concentration, just below the requirement. All other amino acids were balanced and equal in the diets. Arginine supplementation increased protein and fat accretion, without affecting the hepatosomatic or visceralsomatic indices. Dietary arginine correlated with putrescine in the liver (R 0·78, P= 0·01) and with ornithine in the muscle, liver and plasma (P= 0·0002, 0·003 and 0·0002, respectively). The mRNA of ornithine decarboxylase, the enzyme producing putrescine, was up-regulated in the white adipose tissue of fish fed the high-arginine inclusion compared with those fed the low-arginine diet. Concomitantly, spermidine/spermine-(N1)-acetyltransferase, the rate-limiting enzyme for polyamine turnover that consumes acetyl-CoA, showed an increased activity in the liver of fish fed the arginine-supplemented diets. In addition, lower acetyl-CoA concentrations were observed in the liver of fish fed the high-arginine diet, while ATP, which is used in the process of synthesising spermidine and spermine, did not show a similar trend. Gene expression of the rate-limiting enzyme for β-oxidation of long-chain fatty acids, carnitine palmitoyl transferase-1, was up-regulated in the liver of fish fed the high-arginine diet. Taken together, the data support that increased dietary arginine activates polyamine turnover and β-oxidation in the liver of juvenile Atlantic salmon and may act to improve the metabolic status of the fish. PMID:23656796

  4. Dietary arginine affects energy metabolism through polyamine turnover in juvenile Atlantic salmon (Salmo salar).

    PubMed

    Andersen, Synne M; Holen, Elisabeth; Aksnes, Anders; Rønnestad, Ivar; Zerrahn, Jens-Erik; Espe, Marit

    2013-12-14

    In the present study, quadruplicate groups of juvenile Atlantic salmon (Salmo salar) were fed plant protein-based diets with increasing arginine inclusions (range 28·8-37·4 g/kg DM) to investigate whether arginine supplementation affects growth and lipid accumulation through an elevated polyamine turnover. Dietary lysine was held at a constant concentration, just below the requirement. All other amino acids were balanced and equal in the diets. Arginine supplementation increased protein and fat accretion, without affecting the hepatosomatic or visceralsomatic indices. Dietary arginine correlated with putrescine in the liver (R 0·78, P= 0·01) and with ornithine in the muscle, liver and plasma (P= 0·0002, 0·003 and 0·0002, respectively). The mRNA of ornithine decarboxylase, the enzyme producing putrescine, was up-regulated in the white adipose tissue of fish fed the high-arginine inclusion compared with those fed the low-arginine diet. Concomitantly, spermidine/spermine-(N1)-acetyltransferase, the rate-limiting enzyme for polyamine turnover that consumes acetyl-CoA, showed an increased activity in the liver of fish fed the arginine-supplemented diets. In addition, lower acetyl-CoA concentrations were observed in the liver of fish fed the high-arginine diet, while ATP, which is used in the process of synthesising spermidine and spermine, did not show a similar trend. Gene expression of the rate-limiting enzyme for β-oxidation of long-chain fatty acids, carnitine palmitoyl transferase-1, was up-regulated in the liver of fish fed the high-arginine diet. Taken together, the data support that increased dietary arginine activates polyamine turnover and β-oxidation in the liver of juvenile Atlantic salmon and may act to improve the metabolic status of the fish.

  5. Alkyl-methylimidazolium ionic liquids affect the growth and fermentative metabolism of Clostridium sp

    SciTech Connect

    Nancharaiah, Y.V.; Francis, A.

    2011-06-01

    In this study, the effect of ionic liquids, 1-ethyl-3-methylimidazolium acetate [EMIM][Ac], 1-ethyl-3-methylimidazolium diethylphosphate [EMIM][DEP], and 1-methyl-3-methylimidazolium dimethylphosphate [MMIM][DMP] on the growth and glucose fermentation of Clostridium sp. was investigated. Among the three ionic liquids tested, [MMIM][DMP] was found to be least toxic. Growth of Clostridium sp. was not inhibited up to 2.5, 4 and 4 g L{sup -1} of [EMIM][Ac], [EMIM][DEP] and [MMIM][DMP], respectively. [EMIM][Ac] at <2.5 g L{sup -1}, showed hormetic effect and stimulated the growth and fermentation by modulating medium pH. Total organic acid production increased in the presence of 2.5 and 2 g L{sup -1} of [EMIM][Ac] and [MMIM][DMP]. Ionic liquids had no significant influence on alcohol production at <2.5 g L{sup -1}. Total gas production was affected by ILs at {ge}2.5 g L{sup -1} and varied with type of methylimidazolium IL. Overall, the results show that the growth and fermentative metabolism of Clostridium sp. is not impacted by ILs at concentrations below 2.5 g L{sup -1}.

  6. Dietary fatty acids early in life affect lipid metabolism and adiposity in young rats.

    PubMed

    Silva, Ana Paula S; Guimarães, Daniella E D; Mizurini, Daniella M; Maia, Ingrid C; Ortiz-Costa, Susana; Sardinha, Fátima L; do Carmo, Maria G Tavares

    2006-06-01

    The purpose of this study was to evaluate the effects of four isoenergetic diets of differing fat composition on blood lipid profile and adiposity in young rats. Diets containing different lipid sources--partially hydrogenated vegetable oil (PHVO), palm oil (PO), canola oil (CO), and soy oil (SO)--were fed to lactating rats during the 21 days of lactation, and then fed to young males following weaning until the 45th day of life. In vivo lipogenesis rate (LR), lipid content (LC), relative level of FA, and the activity of lipoprotein lipase (LPL) enzyme were measured in epididymal adipose tissue (EPI). Fasting blood lipoproteins and LC in the carcass were also appraised. Body weight of PO and PHVO groups was significantly higher than CO and SO groups from day 14 of lactation to day 45, despite the lower food intake in the PHVO group. PO and PHVO groups presented higher LR and LC in EPI than SO and CO groups. Carcass fat content was significantly higher in PHVO and PO groups than in CO and SO groups. The LPL activity in EPI was unaffected by dietary lipids. PHVO group had increased total cholesterol and TAG concentrations in comparison with the PO group, and significantly lower HDL level compared with the other groups. These results show that the kind of FA in the dietary lipid offered early in life can affect lipid metabolism and adiposity.

  7. Zinc deficiency (ZD) without starvation affects thyroid hormone metabolism of rats

    SciTech Connect

    Lukaski, H.C.; Smith, S.M.; Hall, C.B.; Bucher, D.R. )

    1991-03-15

    Young rats fed diets severely deficient in Zn exhibit impaired growth and endocrine function. These hormone effects may be confounded by cyclical feeding and starvation. To examine the effects of zinc deficiency (ZD) with and without starvation, 40 male weanling Sprague-Dawley rats were fed a semipurified diet containing all essential nutrients and 30 ppm Zn until they weighed 150 g, then were matched by weight into four groups and were fed one of the following diets for 28d: ad lib control Zn diet, marginal ZD diet, severe ZD diet, and C diet pair-fed (PF) in amounts consumed by matched ZD1 rat. Food intake was depressed in ZD1; body weights were reduced in ZD1 and PF. There was no difference in either food intake or weight gain between C and ZD6. ZD reduced liver and femur Zn concentrations. Plasma thyroxine (T{sub 4}) concentration was greater in ZD6 then ZD1 or PF, but less than C; triodothyronine concentration was less in PF than C, but similar to ZD1 and ZD6. Hepatic T{sub 4}-5{prime}-deiodinase activity was greater in ZD6 than ZD1 or PF, but less than C. These findings indicate that altered thyroid hormone metabolism of severe ZD is related to Zn intake and starvation, whereas ZD uncomplicated by starvation affects peripheral deiodination of T{sub 4}, and suggests altered rates of thyroid hormone synthesis or degradation.

  8. Developmental changes in carbon and nitrogen metabolism affect tea quality in different leaf position.

    PubMed

    Li, Zhi-Xin; Yang, Wei-Jun; Ahammed, Golam Jalal; Shen, Chen; Yan, Peng; Li, Xin; Han, Wen-Yan

    2016-09-01

    Leaf position represents a specific developmental stage that influences both photosynthesis and respiration. However, the precise relationships between photosynthesis and respiration in different leaf position that affect tea quality are largely unknown. Here, we show that the effective quantum yield of photosystem II [ΦPSⅡ] as well as total chlorophyll concentration (TChl) of tea leaves increased gradually with leaf maturity. Moreover, respiration rate (RR) together with total nitrogen concentration (TN) decreased persistently, but total carbon remained unchanged during leaf maturation. Analyses of major N-based organic compounds revealed that decrease in TN was attributed to a significant decrease in the concentration of caffeine and amino acids (AA) in mature leaves. Furthermore, soluble sugar (SS) decreased, but starch concentration increased with leaf maturity, indicating that source-sink relationship was altered during tea leaf development. Detailed correlation analysis showed that ΦPSⅡ was negatively correlated with RR, SS, starch, tea polyphenol (TP), total catechins and TN, but positively correlated with TChl; while RR was positively correlated with TN, SS, TP and caffeine, but negatively correlated with TChl and starch concentrations. Our results suggest that biosynthesis of chlorophyll, catechins and polyphenols is closely associated with photosynthesis and respiration in different leaf position that greatly influences the relationship between primary and secondary metabolism in tea plants. PMID:27380366

  9. Inhibitors of plant invertases do not affect the structurally related enzymes of fructan metabolism.

    PubMed

    Kusch, Ute; Harms, Karsten; Rausch, Thomas; Greiner, Steffen

    2009-01-01

    Plant fructan active enzymes (FAZYs), including the enzymes involved in inulin metabolism, namely sucrose:sucrose 1-fructosyltransferase (1-SST; EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (1-FFT; EC 2.4.1.100) and fructan 1-exohydrolase (1-FEH; EC 3.2.1.153), are evolutionarily related to acid invertases (AIs), that is, plant cell wall invertase (CWI) and vacuolar invertase (VI). Acid invertases are post-translationally controlled by proteinaceous inhibitors. Whether FAZYs are subject to similar controls is not known. To probe their possible interactions with invertase inhibitors, we transiently expressed chicory (Cichorium intybus) FAZYs, as well as several previously characterized invertase inhibitors from nonfructan species, and the C. intybus cell wall/vacuolar inhibitor of fructosidase (CiC/VIF), a putative invertase inhibitor of a fructan-accumulating plant, in leaves of Nicotiana benthamiana. Leaf extracts containing recombinant, enzymatically active FAZYs were used to explore the interaction with invertase inhibitors. Neither heterologous inhibitors nor CiC/VIF affected FAZY activities. CiC/VIF was confirmed as an AI inhibitor with a stronger effect on CWI than on VI. Its expression in planta was developmentally regulated (high in taproots, and undetectable in leaves and flowers). In agreement with its target specificities, CiC/VIF was associated with the cell wall. It is concluded that subtle structural differences between AIs and FAZYs result in pronounced selectivity of inhibitor action.

  10. Dietary n-3 PUFA affect lipid metabolism and tissue function-related genes in bovine muscle.

    PubMed

    Hiller, Beate; Hocquette, Jean-Francois; Cassar-Malek, Isabelle; Nuernberg, Gerd; Nuernberg, Karin

    2012-09-01

    Gene expression profiles of bovine longissimus muscle as affected by dietary n-3 v. n-6 fatty acid (FA) intervention were analysed by microarray pre-screening of >3000 muscle biology/meat quality-related genes as well as subsequent quantitative RT-PCR gene expression validation of genes encoding lipogenesis-related transcription factors (CCAAT/enhancer-binding protein β, sterol regulatory element-binding transcription factor 1), key-lipogenic enzymes (acetyl-CoA carboxylase α (ACACA), fatty acid synthase (FASN), stearoyl-CoA desaturase (SCD)), lipid storage-associated proteins (adipose differentiation-related protein (ADFP)) and muscle biology-related proteins (cholinergic receptor, nicotinic, α1, farnesyl diphosphate farnesyl transferase 1, sema domain 3C (SEMA3C)). Down-regulation of ACACA (P = 0·00), FASN (P = 0·09) and SCD (P = 0·02) gene expression upon an n-3 FA intervention directly corresponded to reduced SFA, MUFA and total FA concentrations in longissimus muscle, whereas changes in ADFP (P = 0·00) and SEMA3C (P = 0·05) gene expression indicated improved muscle function via enhanced energy metabolism, vasculogenesis, innervation and mediator synthesis. The present study highlights the significance of dietary n-3 FA intervention on muscle development, maintenance and function, which are relevant for meat quality tailoring of bovine tissues and modulating animal production-relevant physiological processes.

  11. Hepatitis B virus (HBV) X protein-mediated regulation of hepatocyte metabolic pathways affects viral replication.

    PubMed

    Bagga, Sumedha; Rawat, Siddhartha; Ajenjo, Marcia; Bouchard, Michael J

    2016-11-01

    Chronic HBV infection is a risk factor for hepatocellular carcinoma (HCC). The HBV HBx protein stimulates HBV replication and likely influences the development of HBV-associated HCC. Whether HBx affects regulators of metabolism in normal hepatocytes has not been addressed. We used an ex vivo, cultured primary rat hepatocyte system to assess the interplay between HBV replication and mechanistic target of rapamycin complex 1 (mTORC1) signaling. HBx activated mTORC1 signaling; however, inhibition of mTORC1 enhanced HBV replication. HBx also decreased ATP levels and activated the energy-sensing factor AMP-activated protein kinase (AMPK). Inhibition of AMPK decreased HBV replication. Inhibition of AMPK activates mTORC1, and we showed that activated mTORC1 is one factor that reduces HBV replication when AMPK is inhibited. HBx activation of both AMPK and mTORC1 suggests that these activities could provide a balancing mechanism to facilitate persistent HBV replication. HBx activation of mTORC1 and AMPK could also influence HCC development.

  12. Developmental changes in carbon and nitrogen metabolism affect tea quality in different leaf position.

    PubMed

    Li, Zhi-Xin; Yang, Wei-Jun; Ahammed, Golam Jalal; Shen, Chen; Yan, Peng; Li, Xin; Han, Wen-Yan

    2016-09-01

    Leaf position represents a specific developmental stage that influences both photosynthesis and respiration. However, the precise relationships between photosynthesis and respiration in different leaf position that affect tea quality are largely unknown. Here, we show that the effective quantum yield of photosystem II [ΦPSⅡ] as well as total chlorophyll concentration (TChl) of tea leaves increased gradually with leaf maturity. Moreover, respiration rate (RR) together with total nitrogen concentration (TN) decreased persistently, but total carbon remained unchanged during leaf maturation. Analyses of major N-based organic compounds revealed that decrease in TN was attributed to a significant decrease in the concentration of caffeine and amino acids (AA) in mature leaves. Furthermore, soluble sugar (SS) decreased, but starch concentration increased with leaf maturity, indicating that source-sink relationship was altered during tea leaf development. Detailed correlation analysis showed that ΦPSⅡ was negatively correlated with RR, SS, starch, tea polyphenol (TP), total catechins and TN, but positively correlated with TChl; while RR was positively correlated with TN, SS, TP and caffeine, but negatively correlated with TChl and starch concentrations. Our results suggest that biosynthesis of chlorophyll, catechins and polyphenols is closely associated with photosynthesis and respiration in different leaf position that greatly influences the relationship between primary and secondary metabolism in tea plants.

  13. Metabolic and transcriptional response of central metabolism affected by root endophytic fungus Piriformospora indica under salinity in barley.

    PubMed

    Ghaffari, Mohammad Reza; Ghabooli, Mehdi; Khatabi, Behnam; Hajirezaei, Mohammad Reza; Schweizer, Patrick; Salekdeh, Ghasem Hosseini

    2016-04-01

    The root endophytic fungus Piriformospora indica enhances plant adaptation to environmental stress based on general and non-specific plant species mechanisms. In the present study, we integrated the ionomics, metabolomics, and transcriptomics data to identify the genes and metabolic regulatory networks conferring salt tolerance in P. indica-colonized barley plants. To this end, leaf samples were harvested at control (0 mM NaCl) and severe salt stress (300 mM NaCl) in P. indica-colonized and non-inoculated barley plants 4 weeks after fungal inoculation. The metabolome analysis resulted in an identification of a signature containing 14 metabolites and ions conferring tolerance to salt stress. Gene expression analysis has led to the identification of 254 differentially expressed genes at 0 mM NaCl and 391 genes at 300 mM NaCl in P. indica-colonized compared to non-inoculated samples. The integration of metabolome and transcriptome analysis indicated that the major and minor carbohydrate metabolism, nitrogen metabolism, and ethylene biosynthesis pathway might play a role in systemic salt-tolerance in leaf tissue induced by the root-colonized fungus.

  14. Metabolic and transcriptional response of central metabolism affected by root endophytic fungus Piriformospora indica under salinity in barley.

    PubMed

    Ghaffari, Mohammad Reza; Ghabooli, Mehdi; Khatabi, Behnam; Hajirezaei, Mohammad Reza; Schweizer, Patrick; Salekdeh, Ghasem Hosseini

    2016-04-01

    The root endophytic fungus Piriformospora indica enhances plant adaptation to environmental stress based on general and non-specific plant species mechanisms. In the present study, we integrated the ionomics, metabolomics, and transcriptomics data to identify the genes and metabolic regulatory networks conferring salt tolerance in P. indica-colonized barley plants. To this end, leaf samples were harvested at control (0 mM NaCl) and severe salt stress (300 mM NaCl) in P. indica-colonized and non-inoculated barley plants 4 weeks after fungal inoculation. The metabolome analysis resulted in an identification of a signature containing 14 metabolites and ions conferring tolerance to salt stress. Gene expression analysis has led to the identification of 254 differentially expressed genes at 0 mM NaCl and 391 genes at 300 mM NaCl in P. indica-colonized compared to non-inoculated samples. The integration of metabolome and transcriptome analysis indicated that the major and minor carbohydrate metabolism, nitrogen metabolism, and ethylene biosynthesis pathway might play a role in systemic salt-tolerance in leaf tissue induced by the root-colonized fungus. PMID:26951140

  15. The Impact of Anti-Epileptic Drugs on Growth and Bone Metabolism

    PubMed Central

    Fan, Hueng-Chuen; Lee, Herng-Shen; Chang, Kai-Ping; Lee, Yi-Yen; Lai, Hsin-Chuan; Hung, Pi-Lien; Lee, Hsiu-Fen; Chi, Ching-Shiang

    2016-01-01

    Epilepsy is a common neurological disorder worldwide and anti-epileptic drugs (AEDs) are always the first choice for treatment. However, more than 50% of patients with epilepsy who take AEDs have reported bone abnormalities. Cytochrome P450 (CYP450) isoenzymes are induced by AEDs, especially the classical AEDs, such as benzodiazepines (BZDs), carbamazepine (CBZ), phenytoin (PT), phenobarbital (PB), and valproic acid (VPA). The induction of CYP450 isoenzymes may cause vitamin D deficiency, hypocalcemia, increased fracture risks, and altered bone turnover, leading to impaired bone mineral density (BMD). Newer AEDs, such as levetiracetam (LEV), oxcarbazepine (OXC), lamotrigine (LTG), topiramate (TPM), gabapentin (GP), and vigabatrin (VB) have broader spectra, and are safer and better tolerated than the classical AEDs. The effects of AEDs on bone health are controversial. This review focuses on the impact of AEDs on growth and bone metabolism and emphasizes the need for caution and timely withdrawal of these medications to avoid serious disabilities. PMID:27490534

  16. The Impact of Anti-Epileptic Drugs on Growth and Bone Metabolism.

    PubMed

    Fan, Hueng-Chuen; Lee, Herng-Shen; Chang, Kai-Ping; Lee, Yi-Yen; Lai, Hsin-Chuan; Hung, Pi-Lien; Lee, Hsiu-Fen; Chi, Ching-Shiang

    2016-01-01

    Epilepsy is a common neurological disorder worldwide and anti-epileptic drugs (AEDs) are always the first choice for treatment. However, more than 50% of patients with epilepsy who take AEDs have reported bone abnormalities. Cytochrome P450 (CYP450) isoenzymes are induced by AEDs, especially the classical AEDs, such as benzodiazepines (BZDs), carbamazepine (CBZ), phenytoin (PT), phenobarbital (PB), and valproic acid (VPA). The induction of CYP450 isoenzymes may cause vitamin D deficiency, hypocalcemia, increased fracture risks, and altered bone turnover, leading to impaired bone mineral density (BMD). Newer AEDs, such as levetiracetam (LEV), oxcarbazepine (OXC), lamotrigine (LTG), topiramate (TPM), gabapentin (GP), and vigabatrin (VB) have broader spectra, and are safer and better tolerated than the classical AEDs. The effects of AEDs on bone health are controversial. This review focuses on the impact of AEDs on growth and bone metabolism and emphasizes the need for caution and timely withdrawal of these medications to avoid serious disabilities. PMID:27490534

  17. [Drug with a high metabolic activity, cocarnit, in the treatment of diabetic cardiac autonomic neuropathy].

    PubMed

    Popov, S V; Melekhovets', O K; Demikhova, N V; Vynnychenko, L B

    2012-01-01

    Left ventricular diastolic dysfunction in patients with diabetes is formed in the absence of atherosclerotic changes as a consequence of diabetic cardiac autonomic neuropathy in the early stages of diabetes. Progression of autonomic cardiac neuropathy in cardio-vascular type is associated with the violation of energy supply of cells, protein synthesis, electrolyte exchange, the exchange of trace elements, oxidation reduction processes, oxygen-transport function of blood, so that metabolic therapy is carried out to optimize the processes of formation and energy costs. The drug cocarnit activates processes of aerobic oxidation of glucose, as well as providing regulatory influence on the oxidation of fatty acids. Applying of cocarnit in complex therapy in patients with diabetic cardiac autonomic neuropathy found improvement of left ventricular diastolic function, and positive dynamics in the efferent activity balance of the sympathetic and parasympathetic control of heart rate variability, which provides the regression of clinical symptoms. PMID:23356142

  18. The schistosome excretory system: a key to regulation of metabolism, drug excretion and host interaction.

    PubMed

    Kusel, John R; McVeigh, Paul; Thornhill, Joyce A

    2009-08-01

    There is a gulf between the enormous information content of the various genome projects and the understanding of the life of the parasite in the host. In vitro studies with adult Schistosoma mansoni using several substrates suggest that the excretory system contains both P-glycoproteins and multiresistance proteins. If both these families of protein were active in vivo, they could regulate parasite metabolism and be responsible for the excretion of drugs. During skin penetration, membrane-impermeant molecules of a wide range of molecular weights can be taken into the cercaria and schistosomulum through the nephridiopore, through the surface membrane or through both. We speculate that this uptake process might stimulate novel signalling pathways involved in growth and development.

  19. Pollution-induced community tolerance to non-steroidal anti-inflammatory drugs (NSAIDs) in fluvial biofilm communities affected by WWTP effluents.

    PubMed

    Corcoll, Natàlia; Acuña, Vicenç; Barceló, Damià; Casellas, Maria; Guasch, Helena; Huerta, Belinda; Petrovic, Mira; Ponsatí, Lidia; Rodríguez-Mozaz, Sara; Sabater, Sergi

    2014-10-01

    We assessed the tolerance acquired by stream biofilms to two non-steroidal anti-inflammatory-drugs (NSAIDs), ibuprofen and diclofenac. Biofilms came from a stream system receiving the effluent of a wastewater treatment plant (WWTP). The response of biofilms from a non-polluted site (upstream the WWTP) was compared to that of others downstream with relevant and decreasing levels of NSAIDs. Experiments performed in the laboratory following the pollution-induced community tolerance (PICT) approach determined that both algae and microbial communities from biofilms of the sites exposed at the highest concentrations of ibuprofen and diclofenac acquired tolerance to the mixture of these NSAIDs occurring at the sites. It was also observed that the chronic pollution by the WWTP effluent affected the microbial metabolic profile, as well as the structure of the algal community. The low (at ng L(-1) level) but chronic inputs of pharmaceuticals to the river ecosystem result in tolerant communities of lower diversity and altered microbial metabolism.

  20. The affective dimension of pain as a risk factor for drug and alcohol addiction.

    PubMed

    LeBlanc, Dana M; McGinn, M Adrienne; Itoga, Christy A; Edwards, Scott

    2015-12-01

    Addiction, or substance use disorder (SUD), is a devastating psychiatric disease composed of multiple elemental features. As a biobehavioral disorder, escalation of drug and/or alcohol intake is both a cause and consequence of molecular neuroadaptations in central brain reinforcement circuitry. Multiple mesolimbic areas mediate a host of negative affective and motivational symptoms that appear to be central to the addiction process. Brain stress- and reinforcement-related regions such as the central amygdala (CeA), prefrontal cortex (PFC), and nucleus accumbens (NAc) also serve as central processors of ascending nociceptive input. We hypothesize that a sensitization of brain mechanisms underlying the processing of persistent and maladaptive pain contributes to a composite negative affective state to drive the enduring, relapsing nature of addiction, particularly in the case of alcohol and opioid use disorder. At the neurochemical level, pain activates central stress-related neuropeptide signaling, including the dynorphin and corticotropin-releasing factor (CRF) systems, and by this process may facilitate negative affect and escalated drug and alcohol use over time. Importantly, the widespread prevalence of unresolved pain and associated affective dysregulation in clinical populations highlights the need for more effective analgesic medications with reduced potential for tolerance and dependence. The burgeoning epidemic of prescription opioid abuse also demands a closer investigation into the neurobiological mechanisms of how pain treatment could potentially represent a significant risk factor for addiction in vulnerable populations. Finally, the continuing convergence of sensory and affective neuroscience fields is expected to generate insight into the critical balance between pain relief and addiction liability, as well as provide more effective therapeutic strategies for chronic pain and addiction.

  1. A Multiscale Approach to Modelling Drug Metabolism by Membrane-Bound Cytochrome P450 Enzymes

    PubMed Central

    Sansom, Mark S. P.; Mulholland, Adrian J.

    2014-01-01

    Cytochrome P450 enzymes are found in all life forms. P450s play an important role in drug metabolism, and have potential uses as biocatalysts. Human P450s are membrane-bound proteins. However, the interactions between P450s and their membrane environment are not well-understood. To date, all P450 crystal structures have been obtained from engineered proteins, from which the transmembrane helix was absent. A significant number of computational studies have been performed on P450s, but the majority of these have been performed on the solubilised forms of P450s. Here we present a multiscale approach for modelling P450s, spanning from coarse-grained and atomistic molecular dynamics simulations to reaction modelling using hybrid quantum mechanics/molecular mechanics (QM/MM) methods. To our knowledge, this is the first application of such an integrated multiscale approach to modelling of a membrane-bound enzyme. We have applied this protocol to a key human P450 involved in drug metabolism: CYP3A4. A biologically realistic model of CYP3A4, complete with its transmembrane helix and a membrane, has been constructed and characterised. The dynamics of this complex have been studied, and the oxidation of the anticoagulant R-warfarin has been modelled in the active site. Calculations have also been performed on the soluble form of the enzyme in aqueous solution. Important differences are observed between the membrane and solution systems, most notably for the gating residues and channels that control access to the active site. The protocol that we describe here is applicable to other membrane-bound enzymes. PMID:25033460

  2. Dietary folate and choline status differentially affect lipid metabolism and behavior-mediated neurotransmitters in young rats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The relationship between choline and folate metabolisms is an important issue due to the essential role of these nutrients in brain plasticity and cognitive functions. Present study was designed to investigate whether modification of the dietary folate-choline status in young rats would affect brain...

  3. Total gastrectomy may result in reduced drug effectiveness due to an increase in the expression of the drug-metabolizing enzyme Cytochrome P450, in the liver.

    PubMed

    Ishii, Makoto; Toda, Takahiro; Ikarashi, Nobutomo; Kusunoki, Yoshiki; Kon, Risako; Ochiai, Wataru; Machida, Yoshiaki; Sugiyama, Kiyoshi

    2014-01-23

    In patients with gastrectomy, it is possible that drug effectiveness is reduced compared to healthy subjects due to the increased of the drug-metabolizing enzyme, Cytochrome P450 (CYP). The purpose of this study is to verify this possibility. Gastrectomy model mice were prepared to evaluate the expression level of various CYPs in the liver from 2 to 24 weeks post-operation. No significant differences were observed in the protein expression levels of CYP3A, CYP1A, CYP2C, and CYP2D between the sham operation group and the gastrectomy group up to 4 weeks after the gastrectomy. On the other hand, significant increases in the protein expression levels of any CYPs were observed in the gastrectomy group compared to the sham operation group from 12 weeks after the gastrectomy onward. These increases in expression levels were maintained until 24 weeks after the gastrectomy. The examination of metabolic activity in the liver in the gastrectomy group using triazolam revealed that the metabolic activity at 12 weeks after the gastrectomy was significantly increased in the gastrectomy group. The administration of the anticancer drug imatinib, which is a substrate of CYP3A, to mice at 12weeks after gastrectomy resulted in an increase in the metabolic rate, suggesting a possible decrease in drug effectiveness. It has been revealed that drug effectiveness may be reduced after gastrectomy because the expression levels of various CYPs in the liver were increased over a prolonged period. The results of this study can serve as valuable fundamental knowledge for drug therapy in patients with gastrectomy.

  4. Culture surfaces coated with various implant materials affect chondrocyte growth and metabolism.

    PubMed

    Hambleton, J; Schwartz, Z; Khare, A; Windeler, S W; Luna, M; Brooks, B P; Dean, D D; Boyan, B D

    1994-07-01

    to culture surface was comparable, differing primarily in magnitude. Cell maturation-dependent effects were evident when enzyme activity in trypsinized and scraped cells was compared. These results indicate that different surface materials affect chondrocyte metabolism and phenotypic expression in vitro and suggest that implant materials may modulate the phenotypic expression of cells in vivo. PMID:7520486

  5. Pharmacotherapeutic targeting of the endocannabinoid signaling system: Drugs for obesity and the metabolic syndrome

    PubMed Central

    Vemuri, V. Kiran; Janero, David R.; Makriyannis, Alexandros

    2013-01-01

    Endogenous signaling lipids (“endocannabinoids”) functionally related to Δ9-tetrahydrocannabinol, the psychoactive ingredient of marijuana (Cannabis), are important biomediators and metabolic regulators critical to mammalian (patho)physiology. The growing family of endocannabinoids, along with endocannabinoid biosynthetic and inactivating enzymes, transporters, and at least two membrane-bound, G-protein coupled receptors, comprise collectively the mammalian endocannabinoid signaling system. The ubiquitous and diverse regulatory actions of the endocannabinoid system in health and disease have supported the regulatory approval of natural products and synthetic agents as drugs that alter endocannabinoid-system activity. More recent data support the concept that the endocananbinoid system may be modulated for therapeutic gain at discrete pharmacological targets with safety and efficacy. Potential medications based on the endocannabinoid system have thus become a central focus of contemporary translational research for varied indications with important unmet medical needs. One such indication, obesity, is a global pandemic whose etiology has a pathogenic component of endocannabinoid-system hyperactivity and for which current pharmacological treatment is severely limited. Application of high-affinity, selective CB1 cannabinoid receptor ligands to attenuate endocannabinoid signaling represents a state-of-the-art approach for improving obesity pharmacotherapy. To this intent, several selective CB1 receptor antagonists with varied chemical structures are currently in advanced preclinical or clinical trials, and one (rimonabant) has been approved as a weight-management drug in some markets. Emerging preclinical data suggest that CB1 receptor neutral antagonists may represent breakthrough medications superior to antagonists/inverse agonists such as rimonabant for therapeutic attenuation of CB1 receptor transmission. Since obesity is a predisposing condition for the

  6. A self-microemulsifying drug delivery system to overcome intestinal resveratrol toxicity and presystemic metabolism.

    PubMed

    Seljak, Katarina Bolko; Berginc, Katja; Trontelj, Jurij; Zvonar, Alenka; Kristl, Albin; Gašperlin, Mirjana

    2014-11-01

    A mixed lipid-mixed surfactant self-microemulsifying drug delivery system (SMEDDS) was developed to exploit the health benefits of resveratrol, a Biopharmaceutical Classification System Class 2 natural polyphenol, subject to extensive intestinal presystemic metabolism. SMEDDS with a mixed lipid phase (castor oil/Capmul MCM 1:1) and a mixed surfactant phase (Kolliphor EL/Kolliphor RH 40 1:1) was developed and evaluated for its self-emulsifying properties and in vitro dispersion. The impact of SMEDDS on the permeability properties of resveratrol and its metabolite fluxes through the rat intestine and Caco-2 cells was monitored. The inhibitory effect of selected SMEDDS components on the efflux transporters multidrug resistance-associated protein and P-gp as well as cytotoxicity was assessed on Caco-2 cells. The formulation allowed for high resveratrol loading (122.5 mg/g SMEDDS), excellent self-emulsifying properties, and very rapid release. When formulated in SMEDDS, resveratrol metabolite efflux significantly declined. The formulation (SMEDDS without incorporated resveratrol) and its individual components did not compromise in vitro cell vitality and integrity. Mixed lipid-mixed surfactant SMEDDS is a prospective formulation to improve resveratrol biopharmaceutical, pharmacokinetic, and toxicological properties, leading the way to resveratrol use not only as a supplement but also as a pharmacological drug.

  7. In vitro investigations into the roles of drug transporters and metabolizing enzymes in the disposition and drug interactions of dolutegravir, a HIV integrase inhibitor.

    PubMed

    Reese, Melinda J; Savina, Paul M; Generaux, Grant T; Tracey, Helen; Humphreys, Joan E; Kanaoka, Eri; Webster, Lindsey O; Harmon, Kelly A; Clarke, James D; Polli, Joseph W

    2013-02-01

    Dolutegravir (DTG; S/GSK1349572) is a potent HIV-1 integrase inhibitor with a distinct resistance profile and a once-daily dose regimen that does not require pharmacokinetic boosting. This work investigated the in vitro drug transport and metabolism of DTG and assessed the potential for clinical drug-drug interactions. DTG is a substrate for the efflux transporters P-glycoprotein (Pgp) and human breast cancer resistance protein (BCRP). Its high intrinsic membrane permeability limits the impact these transporters have on DTG's intestinal absorption. UDP-glucuronosyltransferase (UGT) 1A1 is the main enzyme responsible for the metabolism of DTG in vivo, with cytochrome P450 (P450) 3A4 being a notable pathway and UGT1A3 and UGT1A9 being only minor pathways. DTG demonstrated little or no inhibition (IC(50) values > 30 μM) in vitro of the transporters Pgp, BCRP, multidrug resistance protein 2, organic anion transporting polypeptide 1B1/3, organic cation transporter (OCT) 1, or the drug metabolizing enzymes CYP1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 3A4, UGT1A1, or 2B7. Further, DTG did not induce CYP1A2, 2B6, or 3A4 mRNA in vitro using human hepatocytes. DTG does inhibit the renal OCT2 (IC(50) = 1.9 μM) transporter, which provides a mechanistic basis for the mild increases in serum creatinine observed in clinical studies. These in vitro studies demonstrate a low propensity for DTG to be a perpetrator of clinical drug interactions and provide a basis for predicting when other drugs could result in a drug interaction with DTG. PMID:23132334

  8. Establishing population distribution of drug-metabolizing enzyme activities for the use of salivary caffeine as a dynamic liver function marker in a Singaporean Chinese population.

    PubMed

    Chia, Hazel Yiting; Yau, Wai-Ping; Ho, Han Kiat

    2016-04-01

    The salivary paraxanthine/caffeine molar ratio has been proposed as a novel dynamic liver function test to guide dose adjustments of drugs hepatically cleared by CYP1A2. Its usability requires an established population norm as well as the factors influencing the ratio and actual concentrations. To address this knowledge gap, salivary caffeine and paraxanthine concentrations were measured at 4 h post caffeine dose in healthy Chinese individuals who had undergone 24 h of caffeine abstinence. The metabolic ratio was calculated and statistical analysis was performed. From the 52 participants (26 males; 30 regular caffeine consumers) recruited, the salivary paraxanthine/caffeine molar ratio was normally distributed with a mean and SD of 0.5 ± 0.2. No statistically significant factors (BMI, body weight, gender and regularity of caffeine intake) affecting the metabolic ratio were found. The caffeine concentration and total caffeine plus paraxanthine concentrations were lower in males than in females, and lower in regular caffeine consumers than in non-regular caffeine consumers. The 4 h salivary metabolic ratio (mean: 0.5) was generally not significantly different from the literature reported salivary, serum and plasma ratios measured at 4-9 h in healthy individuals (mean range 0.4-0.7) but was significantly higher than the literature reported 6 h plasma ratio and salivary ratios measured at 1-6 h in patients with liver disease or mild abnormal liver function tests (mean range 0.03-0.2). Overall, the population norm of the salivary metabolic ratio in a Singaporean Chinese population established in this study is distinct from individuals with liver disease or mild abnormal liver function tests and provides the benchmark for dosage adjustments of drugs metabolized by CYP1A2. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26862045

  9. Ultrasonic Vocalizations as a Measure of Affect in Preclinical Models of Drug Abuse: A Review of Current Findings.

    PubMed

    Barker, David J; Simmons, Steven J; West, Mark O

    2015-01-01

    The present review describes ways in which ultrasonic vocalizations (USVs) have been used in studies of substance abuse. Accordingly, studies are reviewed which demonstrate roles for affective processing in response to the presentation of drug-related cues, experimenter- and self-administered drug, drug withdrawal, and during tests of relapse/reinstatement. The review focuses on data collected from studies using cocaine and amphetamine, where a large body of evidence has been collected. Data suggest that USVs capture animals' initial positive reactions to psychostimulant administration and are capable of identifying individual differences in affective responding. Moreover, USVs have been used to demonstrate that positive affect becomes sensitized to psychostimulants over acute exposure before eventually exhibiting signs of tolerance. In the drug-dependent animal, a mixture of USVs suggesting positive and negative affect is observed, illustrating mixed responses to psychostimulants. This mixture is predominantly characterized by an initial bout of positive affect followed by an opponent negative emotional state, mirroring affective responses observed in human addicts. During drug withdrawal, USVs demonstrate the presence of negative affective withdrawal symptoms. Finally, it has been shown that drug-paired cues produce a learned, positive anticipatory response during training, and that presentation of drug-paired cues following abstinence produces both positive affect and reinstatement behavior. Thus, USVs are a useful tool for obtaining an objective measurement of affective states in animal models of substance abuse and can increase the information extracted from drug administration studies. USVs enable detection of subtle differences in a behavioral response that might otherwise be missed using traditional measures. PMID:26411762

  10. Ultrasonic Vocalizations as a Measure of Affect in Preclinical Models of Drug Abuse: A Review of Current Findings

    PubMed Central

    Barker, David J.; Simmons, Steven J.; West, Mark O.

    2015-01-01

    The present review describes ways in which ultrasonic vocalizations (USVs) have been used in studies of substance abuse. Accordingly, studies are reviewed which demonstrate roles for affective processing in response to the presentation of drug-related cues, experimenter- and self-administered drug, drug withdrawal, and during tests of relapse/reinstatement. The review focuses on data collected from studies using cocaine and amphetamine, where a large body of evidence has been collected. Data suggest that USVs capture animals’ initial positive reactions to psychostimulant administration and are capable of identifying individual differences in affective responding. Moreover, USVs have been used to demonstrate that positive affect becomes sensitized to psychostimulants over acute exposure before eventually exhibiting signs of tolerance. In the drug-dependent animal, a mixture of USVs suggesting positive and negative affect is observed, illustrating mixed responses to psychostimulants. This mixture is predominantly characterized by an initial bout of positive affect followed by an opponent negative emotional state, mirroring affective responses observed in human addicts. During drug withdrawal, USVs demonstrate the presence of negative affective withdrawal symptoms. Finally, it has been shown that drug-paired cues produce a learned, positive anticipatory response during training, and that presentation of drug-paired cues following abstinence produces both positive affect and reinstatement behavior. Thus, USVs are a useful tool for obtaining an objective measurement of affective states in animal models of substance abuse and can increase the information extracted from drug administration studies. USVs enable detection of subtle differences in a behavioral response that might otherwise be missed using traditional measures. PMID:26411762

  11. Metabolic responses to nocturnal eating in men are affected by sources of dietary energy.

    PubMed

    Holmbäck, Ulf; Forslund, Anders; Forslund, Jeanette; Hambraeus, Leif; Lennernäs, Maria; Lowden, Arne; Stridsberg, Mats; Akerstedt, Torbjörn

    2002-07-01

    Because night work is becoming more prevalent, we studied whether feeding at different times of a 24-h period would elicit different metabolic responses and whether dietary macronutrient composition would affect these responses. Seven men (26-43 y, 19.9-26.6 kg/m(2)) consumed two isocaloric diets, in a crossover design. The diets were a high carbohydrate (HC) diet [65 energy % (E%) carbohydrates, 20E% fat] and a high fat (HF) diet (40E% carbohydrates, 45E% fat). After a 6-d diet-adjustment period, the men were kept awake for 24 h and the food (continuation of respective diet) was provided as six isocaloric meals (i.e., every 4 h). Energy and substrate turnover, heart rate, mean arterial pressure (MAP), blood glucose, triacylglycerol (TAG), nonesterified fatty acid (NEFA) and glycerol were measured throughout the 24-h period. Significantly higher energy expenditure and NEFA concentration, and lower blood glucose and TAG concentrations were observed when the men consumed the HF diet than when they consumed the HC diet. Significant circadian patterns were seen in body and skin temperature (nadir, 0400-0500 h). When the men consumed the HF diet, significant circadian patterns were seen in fat oxidation (nadir, 0800-1200 h; plateau, 1200-0800 h), heat release (nadir, 0800-1200 h; plateau, 1600-0800 h), heart rate (nadir, 0000 h), blood glucose (nadir, 0800-1200 h; peak, 0000-0400 h), NEFA (nadir, 0800-1200 h; peak, 1200-2000 h) and TAG (nadir, 0800-1200 h; peak, 0400-0800 h) concentrations. Energy expenditure, carbohydrate oxidation, MAP and glycerol concentration did not display circadian patterns. Unequal variances eradicated most circadian effects in the HC-diet data. The increased TAG concentration in response to feeding at 0400 h might be involved in the higher TAG concentrations seen in shift workers. Distinct macronutrient/circadian-dependent postprandial responses were seen in most studied variables.

  12. Metabolic stressors and signals differentially affect energy allocation between reproduction and immune function.

    PubMed

    Carlton, Elizabeth D; Cooper, Candace L; Demas, Gregory E

    2014-11-01

    Most free-living animals have finite energy stores that they must allocate to different physiological and behavioral processes. In times of energetic stress, trade-offs in energy allocation among these processes may occur. The manifestation of trade-offs may depend on the source (e.g., glucose, lipids) and severity of energy limitation. In this study, we investigated energetic trade-offs between the reproductive and immune systems by experimentally limiting energy availability to female Siberian hamsters (Phodopus sungorus) with 2-deoxy-d-glucose, a compound that disrupts cellular utilization of glucose. We observed how glucoprivation at two levels of severity affected allocation to reproduction and immunity. Additionally, we treated a subset of these hamsters with leptin, an adipose hormone that provides a direct signal of available fat stores, in order to determine how increasing this signal of fat stores influences glucoprivation-induced trade-offs. We observed trade-offs between the reproductive and immune systems and that these trade-offs depended on the severity of energy limitation and exogenous leptin signaling. The majority of the animals experiencing mild glucoprivation entered anestrus, whereas leptin treatment restored estrous cycling in these animals. Surprisingly, virtually all animals experiencing more severe glucoprivation maintained normal estrous cycling throughout the experiment; however, exogenous leptin resulted in lower antibody production in this group. These data suggest that variation in these trade-offs may be mediated by shifts between glucose and fatty acid utilization. Collectively, the results of the present study highlight the context-dependent nature of these trade-offs, as trade-offs induced by the same metabolic stressor can manifest differently depending on its intensity.

  13. Wilson disease: changes in methionine metabolism and inflammation affect global DNA methylation in early liver disease

    PubMed Central

    Medici, Valentina; Shibata, Noreene M.; Kharbanda, Kusum K.; LaSalle, Janine M.; Woods, Rima; Liu, Sarah; Engelberg, Jesse A.; Devaraj, Sridevi; Török, Natalie J.; Jiang, Joy X.; Havel, Peter J.; Lönnerdal, Bo; Kim, Kyoungmi; Halsted, Charles H.

    2012-01-01

    Hepatic methionine metabolism may play an essential role in regulating methylation status and liver injury in Wilson disease (WD) through the inhibition of S-adenosylhomocysteine hydrolase (SAHH) by copper (Cu) and the consequent accumulation of S-adenosylhomocysteine (SAH). We studied the transcript levels of selected genes related to liver injury, levels of SAHH, SAH, DNA methyltransferases genes (Dnmt1, Dnmt3a, Dnmt3b) and global DNA methylation in the tx-j mouse (tx-j), an animal model of WD. Findings were compared to those in control C3H mice, and in response to Cu chelation by penicillamine (PCA) and dietary supplementation of the methyl donor betaine to modulate inflammatory and methylation status. Transcript levels of selected genes related to endoplasmic reticulum stress, lipid synthesis, and fatty acid oxidation were down-regulated at baseline in tx-j mice, further down-regulated in response to PCA, and showed little to no response to betaine. Hepatic Sahh transcript and protein levels were reduced in tx-j mice with consequent increase of SAH levels. Hepatic Cu accumulation was associated with inflammation, as indicated by histopathology and elevated serum ALT and liver tumor necrosis factor alpha (Tnf-α) levels. Dnmt3b was down-regulated in tx-j mice together with global DNA hypomethylation. PCA treatment of tx-j mice reduced Tnf-α and ALT levels, betaine treatment increased S-adenosylmethionine and up-regulated Dnmt3b levels, and both treatments restored global DNA methylation levels. Conclusion: reduced hepatic Sahh expression was associated with increased liver SAH levels in the tx-j model of WD, with consequent global DNA hypomethylation. Increased global DNA methylation was achieved by reducing inflammation by Cu chelation or by providing methyl groups. We propose that increased SAH levels and inflammation affect widespread epigenetic regulation of gene expression in WD. PMID:22945834

  14. Host-related metabolic cues affect colonization strategies of a root endophyte

    PubMed Central

    Lahrmann, Urs; Ding, Yi; Banhara, Aline; Rath, Magnus; Hajirezaei, Mohammad R.; Döhlemann, Stefanie; von Wirén, Nicolaus; Parniske, Martin; Zuccaro, Alga

    2013-01-01

    The mechanisms underpinning broad compatibility in root symbiosis are largely unexplored. The generalist root endophyte Piriformospora indica establishes long-lasting interactions with morphologically and biochemically different hosts, stimulating their growth, alleviating salt stress, and inducing local and systemic resistance to pathogens. Cytological studies and global investigations of fungal transcriptional responses to colonization of barley and Arabidopsis at different symbiotic stages identified host-dependent colonization strategies and host-specifically induced effector candidates. Here, we show that in Arabidopsis, P. indica establishes and maintains biotrophic nutrition within living epidermal cells, whereas in barley the symbiont undergoes a nutritional switch to saprotrophy that is associated with the production of secondary thinner hyphae in dead cortex cells. Consistent with a diversified trophic behavior and with the occurrence of nitrogen deficiency at the onset of saprotrophy in barley, fungal genes encoding hydrolytic enzymes and nutrient transporters were highly induced in this host but not in Arabidopsis. Silencing of the high-affinity ammonium transporter PiAMT1 gene, whose transcripts are accumulating during nitrogen starvation and in barley, resulted in enhanced colonization of this host, whereas it had no effect on the colonization of Arabidopsis. Increased levels of free amino acids and reduced enzymatic activity for the cell-death marker VPE (vacuolar-processing enzyme) in colonized barley roots coincided with an extended biotrophic lifestyle of P. indica upon silencing of PiAMT1. This suggests that PiAmt1 functions as a nitrogen sensor mediating the signal that triggers the in planta activation of the saprotrophic program. Thus, host-related metabolic cues affect the expression of P. indica’s alternative lifestyles. PMID:23918389

  15. Metabolic responses to nocturnal eating in men are affected by sources of dietary energy.

    PubMed

    Holmbäck, Ulf; Forslund, Anders; Forslund, Jeanette; Hambraeus, Leif; Lennernäs, Maria; Lowden, Arne; Stridsberg, Mats; Akerstedt, Torbjörn

    2002-07-01

    Because night work is becoming more prevalent, we studied whether feeding at different times of a 24-h period would elicit different metabolic responses and whether dietary macronutrient composition would affect these responses. Seven men (26-43 y, 19.9-26.6 kg/m(2)) consumed two isocaloric diets, in a crossover design. The diets were a high carbohydrate (HC) diet [65 energy % (E%) carbohydrates, 20E% fat] and a high fat (HF) diet (40E% carbohydrates, 45E% fat). After a 6-d diet-adjustment period, the men were kept awake for 24 h and the food (continuation of respective diet) was provided as six isocaloric meals (i.e., every 4 h). Energy and substrate turnover, heart rate, mean arterial pressure (MAP), blood glucose, triacylglycerol (TAG), nonesterified fatty acid (NEFA) and glycerol were measured throughout the 24-h period. Significantly higher energy expenditure and NEFA concentration, and lower blood glucose and TAG concentrations were observed when the men consumed the HF diet than when they consumed the HC diet. Significant circadian patterns were seen in body and skin temperature (nadir, 0400-0500 h). When the men consumed the HF diet, significant circadian patterns were seen in fat oxidation (nadir, 0800-1200 h; plateau, 1200-0800 h), heat release (nadir, 0800-1200 h; plateau, 1600-0800 h), heart rate (nadir, 0000 h), blood glucose (nadir, 0800-1200 h; peak, 0000-0400 h), NEFA (nadir, 0800-1200 h; peak, 1200-2000 h) and TAG (nadir, 0800-1200 h; peak, 0400-0800 h) concentrations. Energy expenditure, carbohydrate oxidation, MAP and glycerol concentration did not display circadian patterns. Unequal variances eradicated most circadian effects in the HC-diet data. The increased TAG concentration in response to feeding at 0400 h might be involved in the higher TAG concentrations seen in shift workers. Distinct macronutrient/circadian-dependent postprandial responses were seen in most studied variables. PMID:12097665

  16. Temperature-induced elevation of basal metabolic rate does not affect testis growth in great tits.

    PubMed

    Caro, Samuel P; Visser, Marcel E

    2009-07-01

    The timing of reproduction varies from year to year in many bird species. To adjust their timing to the prevailing conditions of that year, birds use cues from their environment. However, the relative importance of these cues, such as the initial predictive (e.g. photoperiod) and the supplemental factors (e.g. temperature), on the seasonal sexual development are difficult to distinguish. In particular, the fine-tuning effect of temperature on gonadal growth is not well known. One way temperature may affect timing is via its strong effect on energy expenditure as gonadal growth is an energy-demanding process. To study the interaction of photoperiod and temperature on gonadal development, we first exposed 35 individually housed male great tits (Parus major) to mid-long days (after 6 weeks of 8 h L:16 h D at 15 degrees C, photoperiod was set to 13 h L:11 h D at 15 degrees C). Two weeks later, for half of the males the temperature was set to 8 degrees C, and for the other half to 22 degrees C. Unilateral laparotomies were performed at weeks 5 (i.e one week before the birds were transferred to mid-long days), 8 and 11 to measure testis size. Two measures of basal metabolic rate (BMR) were performed at the end of the experiment (weeks 11 and 12). Testis size increased significantly during the course of the experiment, but independently of the temperature treatment. BMR was significantly higher in birds exposed to the cold treatment. These results show that temperature-related elevation of BMR did not impair the long-day-induced testis growth in great tits. As a consequence, temperature may not be a crucial cue and/or constraint factor in the fine-tuning of the gonadal recrudescence in male great tits, and testis growth is not a high energy-demanding seasonal process. PMID:19525424

  17. Studies on drug metabolism by fungi colonizing decomposing human cadavers. Part II: biotransformation of five model drugs by fungi isolated from post-mortem material.

    PubMed

    Martínez-Ramírez, Jorge A; Walther, Grit; Peters, Frank T

    2015-04-01

    The present study investigated the in vitro metabolic capacity of 28 fungal strains isolated from post-mortem material towards five model drugs: amitriptyline, metoprolol, mirtazapine, promethazine, and zolpidem. Each fungal strain was incubated at 25 °C for up to 120 h with each of the five models drugs. Cunninghamella elegans was used as positive control. Aliquots of the incubation mixture were centrifuged and 50 μL of the supernatants were diluted and directly analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with product ion scanning. The remaining mixture was analyzed by full scan gas chromatography-mass spectrometry (GC-MS) after liquid-liquid extraction and acetylation. The metabolic activity was evaluated through the total number of detected metabolites (NDM) produced in each model and fungal strains and the percentage of parent drug remaining (%RPD) after up to five days of incubation. All the tested fungal strains were capable of forming mammalian phase I metabolites. Fungi from the normal fungal flora of the human body such as Candida sp., Geotrichum candidum, and Trichosporon asahii) formed up to seven metabolites at %RPD values greater than 52% but no new fungal metabolites (NFM). In contrast, some airborne fungal strains like Bjerkandera adusta, Chaetomium sp, Coriolopsis sp., Fusarium solani and Mucor plumbeus showed NDM values exceeding those of the positive control, complete metabolism of the parent drug in some models and formation of NFM. NFM (numbers in brackets) were detected in four of the five model drugs: amitriptyline (18), metoprolol (4), mirtazapine (8), and zolpidem (2). The latter NFM are potential candidates for marker substances indicating post-mortem fungal metabolism. PMID:24898183

  18. Water deficit alters differentially metabolic pathways affecting important flavor and quality traits in grape berries of Cabernet Sauvignon and Chardonnay

    PubMed Central

    Deluc, Laurent G; Quilici, David R; Decendit, Alain; Grimplet, Jérôme; Wheatley, Matthew D; Schlauch, Karen A; Mérillon, Jean-Michel; Cushman, John C; Cramer, Grant R

    2009-01-01

    Background Water deficit has significant effects on grape berry composition resulting in improved wine quality by the enhancement of color, flavors, or aromas. While some pathways or enzymes affected by water deficit have been identified, little is known about the global effects of water deficit on grape berry metabolism. Results The effects of long-term, seasonal water deficit on berries of Cabernet Sauvignon, a red-wine grape, and Chardonnay, a white-wine grape were analyzed by integrated transcript and metabolite profiling. Over the course of berry development, the steady-state transcript abundance of approximately 6,000 Unigenes differed significantly between the cultivars and the irrigation treatments. Water deficit most affected the phenylpropanoid, ABA, isoprenoid, carotenoid, amino acid and fatty acid metabolic pathways. Targeted metabolites were profiled to confirm putative changes in specific metabolic pathways. Water deficit activated the expression of numerous transcripts associated with glutamate and proline biosynthesis and some committed steps of the phenylpropanoid pathway that increased anthocyanin concentrations in Cabernet Sauvignon. In Chardonnay, water deficit activated parts of the phenylpropanoid, energy, carotenoid and isoprenoid metabolic pathways that contribute to increased concentrations of antheraxanthin, flavonols and aroma volatiles. Water deficit affected the ABA metabolic pathway in both cultivars. Berry ABA concentrations were highly correlated with 9-cis-epoxycarotenoid dioxygenase (NCED1) transcript abundance, whereas the mRNA expression of other NCED genes and ABA catabolic and glycosylation processes were largely unaffected. Water deficit nearly doubled ABA concentrations within berries of Cabernet Sauvignon, whereas it decreased ABA in Chardonnay at véraison and shortly thereafter. Conclusion The metabolic responses of grapes to water deficit varied with the cultivar and fruit pigmentation. Chardonnay berries, which lack any

  19. The METEOR study of diabetes and other metabolic disorders in patients with schizophrenia treated with antipsychotic drugs. I. Methodology.

    PubMed

    De Hert, Marc; Mauri, Mauro; Shaw, Ken; Wetterling, Tilman; Doble, Adam; Giudicelli, Agnès; Falissard, Bruno

    2010-12-01

    Patients with schizophrenia present a two- to three-fold higher prevalence of diabetes, of metabolic syndrome and of cardiovascular morbidity. The reason for this increased prevalence may involve intrinsic vulnerability, lifestyle factors and iatrogenic effects of antipsychotic drugs. The objective of this multinational, cross-sectional, pharmacoepidemiological study was to determine the prevalence of diabetes, lipid disorders, obesity, hypertension and the metabolic syndrome in patients with schizophrenia treated with antipsychotic drugs. Particular attention was taken to acquire data on a wide a range as possible of demographic, clinical and lifestyle variables that may influence the risk of metabolic disorders, which were taken into account in the calculation of prevalence data by propensity scoring. The study included 2270 subjects from 16 European countries, predominantly from Central and Eastern Europe. The proportion of subjects presenting the pathologies of interest was relatively high, ranging from 28% for glycaemic disorders to 70% for lipid disorders.

  20. Metabolism

    MedlinePlus

    Metabolism refers to all the physical and chemical processes in the body that convert or use energy, ... Tortora GJ, Derrickson BH. Metabolism. In: Tortora GJ, Derrickson BH. Principles of Anatomy and Physiology . 14th ed. Hoboken, NJ: John H Wiley and Sons; 2013: ...

  1. Difference in the Pharmacokinetics and Hepatic Metabolism of Antidiabetic Drugs in Zucker Diabetic Fatty and Sprague-Dawley Rats.

    PubMed

    Zhou, Xin; Rougée, Luc R A; Bedwell, David W; Cramer, Jeff W; Mohutsky, Michael A; Calvert, Nathan A; Moulton, Richard D; Cassidy, Kenneth C; Yumibe, Nathan P; Adams, Lisa A; Ruterbories, Kenneth J

    2016-08-01

    The Zucker diabetic fatty (ZDF) rat, an inbred strain of obese Zucker fatty rat, develops early onset of insulin resistance and displays hyperglycemia and hyperlipidemia. The phenotypic changes resemble human type 2 diabetes associated with obesity and therefore the strain is used as a pharmacological model for type 2 diabetes. The aim of the current study was to compare the pharmacokinetics and hepatic metabolism in male ZDF and Sprague-Dawley (SD) rats of five antidiabetic drugs that are known to be cleared via various mechanisms. Among the