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Sample records for islet damage induced

  1. Glutamine induces heat-shock protein-70 and glutathione expression and attenuates ischemic damage in rat islets.

    PubMed

    Jang, H J; Kwak, J H; Cho, E Y; We, Y M; Lee, Y H; Kim, S C; Han, D J

    2008-10-01

    The transplantation of isolated islets is believed to be an attractive approach for cure of diabetes mellitus. Heat-shock protein (HSP70), which plays a vital role in cellular protection, has been detected in various tissues subjected to stress. Glutamine (GLN) is an important cellular fuel and an essential precursor for the antioxidant glutathione (GSH). It is believed to enhance cellular survival against a variety of stressful stimuli through HSP70. Thus, we performed this study to examine the hypothesis that preoperative GLN administration induces HSP70 and GSH expression before islet transplantation attenuating ischemic damage to rat islets. Adult male Sprague-Dawley (SD) rats were randomly divided into two groups according to the administration of GLN after islet isolation. Group A served as the controls, receiving no GLN. Group B islet cells were cultured with L-GLN (10 mmol/L) supplementation for 24 hours. The GSH levels were measured in islet cells. Both HSP70 and proteins related to apoptosis were analyzed in islet cells by Western blots. Isolated rat islets were cultured with interleukin (IL)-1beta. Nitrite production was measured using the Griess reagent. The GSH levels were significantly elevated in the glutamine-treated group. HSP70 expression in islets treated with GLN was markedly stronger compared with the control group. The basal Bcl-2 expression was markedly increased by GLN treatment. The GLN-treated group showed attenuated IL-1beta-induced injury in association with NO production. These results suggested that preoperative GLN administration induced HSP70 and GSH expressions before islet transplantation, thus attenuating IL-1beta-induced injury in association with NO production and apoptosis, which might be potential tool to mitigate the ischemic damage to islet cells and the early inflammation at the site of implantation through a self-protective mechanism.

  2. Reg3α Overexpression Protects Pancreatic β Cells from Cytokine-Induced Damage and Improves Islet Transplant Outcome

    PubMed Central

    Ding, Ying; Xu, Yuemei; Shuai, Xuanyu; Shi, Xuhui; Chen, Xiang; Huang, Wenbin; Liu, Yun; Liang, Xiubin; Zhang, Zhihong; Su, Dongming

    2014-01-01

    The process of islet transplantation for treating type 1 diabetes has been limited by the high level of graft failure. This may be overcome by locally delivering trophic factors to enhance engraftment. Regenerating islet-derived protein 3α (Reg3α) is a pancreatic secretory protein which functions as an antimicrobial peptide in control of inflammation and cell proliferation. In this study, to investigate whether Reg3α could improve islet engraftment, a marginal mass of syngeneic islets pretransduced with adenoviruses expressing Reg3α or control EGFP were transplanted under the renal capsule of streptozotocin-induced diabetic mice. Mice receiving islets with elevated Reg3α production exhibited significantly lower blood glucose levels (9.057 ± 0.59 mmol/L versus 13.48 ± 0.35 mmol/L, P < 0.05) and improved glucose-stimulated insulin secretion (1.80 ± 0.17 ng/mL versus 1.16 ± 0.16 ng/mL, P < 0.05) compared with the control group. The decline of apoptotic events (0.57% ± 0.15% versus 1.06% ± 0.07%, P < 0.05) and increased β-cell proliferation (0.70% ± 0.10% versus 0.36% ± 0.14%, P < 0.05) were confirmed in islet grafts overexpressing Reg3α by morphometric analysis. Further experiments showed that Reg3α production dramatically protected cultured islets and pancreatic β cells from cytokine-induced apoptosis and the impairment of glucose-stimulated insulin secretion. Moreover, exposure to cytokines led to the activation of MAPKs in pancreatic β cells, which was reversed by Reg3α overexpression in contrast to control group. These results strongly suggest that Reg3α could enhance islet engraftments through its cytoprotective effect and advance the therapeutic efficacy of islet transplantation. PMID:25826674

  3. Mechanism of Inhibition of Human Islet Amyloid Polypeptide-Induced Membrane Damage by a Small Organic Fluorogen

    NASA Astrophysics Data System (ADS)

    Li, Xiaoxu; Wan, Mingwei; Gao, Lianghui; Fang, Weihai

    2016-02-01

    Human islet amyloid polypeptide (hIAPP) is believed to be responsible for the death of insulin-producing β-cells. However, the mechanism of membrane damage at the molecular level has not been fully elucidated. In this article, we employ coarse- grained dissipative particle dynamics simulations to study the interactions between a lipid bilayer membrane composed of 70% zwitterionic lipids and 30% anionic lipids and hIAPPs with α-helical structures. We demonstrated that the key factor controlling pore formation is the combination of peptide charge-induced electroporation and peptide hydrophobicity-induced lipid disordering and membrane thinning. According to these mechanisms, we suggest that a water-miscible tetraphenylethene BSPOTPE is a potent inhibitor to rescue hIAPP-induced cytotoxicity. Our simulations predict that BSPOTPE molecules can bind directly to the helical regions of hIAPP and form oligomers with separated hydrophobic cores and hydrophilic shells. The micelle-like hIAPP-BSPOTPE clusters tend to be retained in the water/membrane interface and aggregate therein rather than penetrate into the membrane. Electrostatic attraction between BSPOTPE and hIAPP also reduces the extent of hIAPP binding to the anionic lipid bilayer. These two modes work together and efficiently prevent membrane poration.

  4. Global gene expression profiling of pancreatic islets in mice during streptozotocin-induced β-cell damage and pancreatic Glp-1 gene therapy.

    PubMed

    Tonne, Jason M; Sakuma, Toshie; Deeds, Michael C; Munoz-Gomez, Miguel; Barry, Michael A; Kudva, Yogish C; Ikeda, Yasuhiro

    2013-09-01

    Streptozotocin (STZ), a glucosamine-nitrosourea compound, has potent genotoxic effects on pancreatic β-cells and is frequently used to induce diabetes in experimental animals. Glucagon-like peptide-1 (GLP-1) has β-cell protective effects and is known to preserve β-cells from STZ treatment. In this study, we analyzed the mechanisms of STZ-induced diabetes and GLP-1-mediated β-cell protection in STZ-treated mice. At 1 week after multiple low-dose STZ administrations, pancreatic β-cells showed impaired insulin expression, while maintaining expression of nuclear Nkx6.1. This was accompanied by significant upregulation of p53-responsive genes in islets, including a mediator of cell cycle arrest, p21 (also known as Waf1 and Cip1). STZ treatment also suppressed expression of a wide range of genes linked with key β-cell functions or diabetes development, such as G6pc2, Slc2a2 (Glut2), Slc30a8, Neurod1, Ucn3, Gad1, Isl1, Foxa2, Vdr, Pdx1, Fkbp1b and Abcc8, suggesting global β-cell defects in STZ-treated islets. The Tmem229B, Prss53 and Ttc28 genes were highly expressed in untreated islets and strongly suppressed by STZ, suggesting their potential roles in β-cell function. When a pancreas-targeted adeno-associated virus (AAV) vector was employed for long-term Glp-1 gene delivery, pancreatic GLP-1 expression protected mice from STZ-induced diabetes through preservation of the β-cell mass. Despite its potent β-cell protective effects, however, pancreatic GLP-1 overexpression showed limited effects on the global gene expression profiles in the islets. Network analysis identified the programmed-cell-death-associated pathways as the most relevant network in Glp-1 gene therapy. Upon pancreatic GLP-1 expression, upregulation of Cxcl13 and Nptx2 was observed in STZ-damaged islets, but not in untreated normal islets. Given the pro-β-cell-survival effects of Cxcl12 (Sdf-1) in inducing GLP-1 production in α-cells, pancreatic GLP-1-mediated Cxcl13 induction might also play a

  5. Possible involvement of iNOS and TNF-α in nutritional intervention against nicotine-induced pancreatic islet cell damage.

    PubMed

    Bhattacharjee, Ankita; Prasad, Shilpi Kumari; Pal, Swagata; Maji, Bithin; Banerjee, Arnab; Das, Debasmita; Bose, Ananya; Chatterjee, Nabanita; Mukherjee, Sandip

    2016-12-01

    Nicotine is the more abundant and most significant components of cigarette smoke. Epidemiological evidence strongly suggests an association between cigarette smoking and pancreatic injury. Although effects of smoking on endocrine pancreas are still controversial Here, we examined the impact and underlying mechanisms of action of folic acid and vitamin B12 on nicotine induced damage in pancreatic islets of rats. Male Wistar rats were treated with nicotine (3mg/kg body weight/day, intraperitonealy) with or without folic acid (36μg/kg body weight/day, orally) and vitamin B12 (0.63μg/kg body weight/day, orally) for 21days. Supplementation with folic acid and vitamin B12 suppressed the nicotine induced changes in HbA1c, insulin, TNF-α, IL-6, generation of reactive oxygen species, and attenuated the changes in markers of oxidative stress. Moreover, folic acid and vitamin B12 also counteracted the increased expression of protein and mRNA contents of TNF-α and iNOS produced by nicotine. Further, folic acid and vitamin B12 in combination limits the nicotine induced changes in cell cycle and excessive apoptosis of the pancreatic β-cells and also successfully blunted the nicotine induced alteration in loss of mitochondrial membrane potential. In conclusion, data demonstrate that folic acid and vitamin B12 may be possible nutritional intervention against cellular oxidative stress, which is a critical step in nicotine-mediated islet injury, and improves islet cell functional status by scavenging free radicals and by inhibiting the generation of pro-inflammatory mediators.

  6. Damage to pancreatic acinar cells and preservation of islets of Langerhans in a rat model of acute pancreatitis induced by Karwinskia humboldtiana (buckthorn).

    PubMed

    Carcano-Diaz, Katya; Garcia-Garcia, Aracely; Segoviano-Ramirez, Juan Carlos; Rodriguez-Rocha, Humberto; Loera-Arias, Maria de Jesus; Garcia-Juarez, Jaime

    2016-09-01

    Karwinskia humboldtiana (Kh) is a poisonous plant that grows in some regions of the American continent. Consuming large amounts of Kh fruit results in acute intoxication leading to respiratory failure, culminating in death within days. There is evidence of histological damage to the lungs, liver, and kidneys following accidental and experimental Kh intoxication. To date, the microscopic effect of Kh consumption on the pancreas has not been described. We examined the early effects of Kh fruit on pancreatic tissue at different stages of acute intoxication in the Wistar rat. We found progressive damage confined to the exocrine pancreas, starting with a reduction in the number of zymogen granules, loss of acinar architecture, the presence of autophagy-like vesicles, apoptosis and inflammatory infiltrate. The pancreatic pathology culminated in damaged acini characterized by necrosis and edema, with a complete loss of lobular architecture. Interestingly, the morphology of the islets of Langerhans was conserved throughout our evaluations. Taken together, our results indicate the damage induced by a high dose of Kh fruit in the Wistar rat is consistent with an early acute necrotizing pancreatitis that exclusively affects the exocrine pancreas. Therefore, this system might be useful as an animal model to study the treatment of pancreatic diseases. More importantly, as the islets of Langerhans were preserved, the active compounds of Kh fruit could be utilized for the treatment of acinar pancreatic cancer. Further studies might provide insight into the severity of acute Kh intoxication in humans and influence the design of treatments for pancreatic diseases and acinar pancreatic cancer.

  7. Genistein reduces hyperglycemia and islet cell loss in a high-dosage manner in rats with alloxan-induced pancreatic damage.

    PubMed

    Yang, Weixia; Wang, Siwang; Li, Li; Liang, Zongsuo; Wang, Lisheng

    2011-04-01

    Elucidate whether genistein (a soy-derived isoflavone) possesses the capacity to alleviate hyperglycemia and minimize islet cell loss after the onset of diabetes and whether the beneficial effect of genistein is dosage dependent. Alloxan-induced diabetic male Sprague-Dawley rats were randomly divided into 5 groups (10 rats per group) and treated with saline, vehicle, and 3 different dosages of genistein by daily gavage. Blood glucose and insulin levels, body weight, and oral glucose tolerance test were assessed; histological changes in pancreatic islets were quantified. In addition, rat islets were isolated, cultured, and exposed to alloxan in the presence or absence of genistein. The survival and the proliferation of islet cells were assessed, and insulin levels in the culture supernatant were measured. In vivo high-dose (30 mg/kg per day) but not low-dose genistein significantly decreases weight loss, hyperglycemia, and islet cell loss in alloxan-induced diabetic rats, while increasing blood insulin levels and glucose tolerance. In vitro experiments reveal that genistein improves islet cell survival and proliferation and facilitates insulin production after alloxan injury. Genistein possesses the capacity to reduce hyperglycemia via minimization of islet cell loss in a dosage-dependent manner (estimating >5-fold than physical intakes) after the onset of diabetes.

  8. TCF2 attenuates FFA-induced damage in islet β-cells by regulating production of insulin and ROS.

    PubMed

    Quan, Xiaojuan; Zhang, Lin; Li, Yingna; Liang, Chunlian

    2014-07-30

    Free fatty acids (FFAs) are cytotoxic to pancreatic islet β-cells and play a crucial role in the diabetes disease process. A recent study revealed a down-regulation of transcription factor 2 (TCF2) levels during FFA-mediated cytotoxicity in pancreatic β-cells. However, its function during this process and the underlying mechanism remains unclear. In this study, treatment with palmitic acid (PA) at high levels (400 and 800 μM) decreased β-cell viability and TCF2 protein expression, along with the glucose-stimulated insulin secretion (GSIS). Western and RT-PCR analysis confirmed the positive regulatory effect of TCF2 on GSIS through promotion of the key regulators pancreatic duodenal homeobox-1 (PDX1) and glucose transporter 2 (GLUT2) in β-cells. In addition, both PI3K/AKT and MEK/ERK showed decreased expression in PA (800 μM)-treated β-cells. Overexpression of TCF2 could effectively restore the inhibitory effect of PA on the activation of PI3K/AKT and MEK/ERK as well as β-cell viability, simultaneously, inhibited PA-induced reactive oxygen species (ROS) generation. After blocking the PI3K/AKT and MAPK/ERK signals with their specific inhibitor, the effect of overexpressed TCF2 on β-cell viability and ROS production was obviously attenuated. Furthermore, a protective effect of TCF2 on GSIS by positive modulation of JNK-PDX1/GLUT2 signaling was also confirmed. Accordingly, our study has confirmed that TCF2 positively modulates insulin secretion and further inhibits ROS generation via the PI3K/AKT and MEK/ERK signaling pathways. Our work may provide a new therapeutic target to achieve prevention and treatment of diabetes.

  9. Microassay for glucose-induced preproinsulin mRNA expression to assess islet functional potency for islet transplantation

    PubMed Central

    Omori, Keiko; Mitsuhashi, Masato; Todorov, Ivan; Rawson, Jeffrey; Shiang, Keh-Dong; Kandeel, Fouad; Mullen, Yoko

    2009-01-01

    Background The capacity for insulin synthesis in islets is important for islet transplantation to succeed. We developed a micro assay that evaluates the potency of human islets by measuring changes in glucose induced insulin gene (INS) expression using a single islet in octuplicate samples. Methods Poly (A)+ mRNA was purified from a set of single handpicked human islets. Glucose induced mature (post-spliced) and premature (pre-spliced) insulin mRNA were quantified by RT-PCR using several insulin mRNA primers designed at different locations including, intron, exon, and an exon-intron junction. Results The synthesis of premature INS mRNA was significantly increased in islets exposed to high glucose for 16 hours (vs. 4-hour, p<0.01), whereas mature INS mRNA showed no difference. Glucose-induced premature INS mRNA synthesis was attenuated in heat-damaged islets. Stimulation index (SI) calculated by normalizing premature by mature INS mRNA (SI_INS mRNA) positively correlated with SI of insulin release (SI_16h-insulin) from the same set of islets during 16-hour incubation in high or low glucose media, as well as SI of glucose-mediated insulin release obtained from the same islet lot in a perifusion system (N=12). Furthermore, linear multiple regression analysis using SI_INS mRNA and SI_16h-insulin predicted islet transplantation outcome in NODscid mice (N=8). Conclusion The measurement of glucose induced premature INS mRNA normalized by mature INS mRNA can be used to assess the functional quality of human islets and may predict islet function after transplantation in type 1 diabetic patients. PMID:20098276

  10. 5,7-dihydroxy-3,4,6-trimethoxyflavone attenuates ischemic damage and apoptosis in mouse islets.

    PubMed

    Kim, J Y; Kim, S S; Jang, H J; Oh, M Y; Lee, D H; Eom, D W; Kang, K S; Kim, S N; Kwan, H C; Ham, J Y; Kim, W J; Jang, D S; Han, D J

    2015-05-01

    The transplantation of isolated pancreatic islets is a promising treatment for diabetes. 5,7-dihydroxy-3,4,6-trimethoxyflavone (Eupatilin), a pharmacologically active flavone derived from the Artemisia plant species, has been reported to have antioxidant and anti-inflammatory activities. This study examines the hypothesis that preoperative eupatilin treatment can attenuate ischemic damage and apoptosis before islet transplantation. Islets isolated from Balb/c mice were randomly divided into 2 groups, and cultured in medium supplemented with or without eupatilin. In vitro islet viability and function were assessed. After treatment with a cytokine cocktail consisting of tumor necrosis factor (TNF)-α, interferon (INF)-γ, and interleukin (IL)-1β, islet cell viability, function, and apoptotic status were determined. The glutathione (GSH) and nitrous oxide (NO) levels were also measured. Proteins related to apoptosis were analyzed using Western blotting. There was no difference in cell viability between the 2 groups. Islets cultured in the medium supplemented with eupatilin showed 1.4-fold higher glucose-induced insulin secretion than the islets cultured in the medium without eupatilin. After treatment with a cytokine cocktail, glucose-induced insulin release and the total insulin content of the islets were significantly improved in eupatilin-pretreated islets compared with islets not treated with eupatilin. Apoptosis was significantly decreased, and GSH levels were elevated in the eupatilin-pretreated group. Cytokine-only treated islets produced significantly higher levels of NO, iNOS, and caspase-3 than islets pretreated with eupatilin before cytokine treatment. These results suggest that preoperative eupatilin administration enhances islet function before transplantation and attenuates the cytokine-induced damage associated with NO production and apoptosis. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Leptin- or troglitazone-induced lipopenia protects islets from interleukin 1beta cytotoxicity.

    PubMed Central

    Shimabukuro, M; Koyama, K; Lee, Y; Unger, R H

    1997-01-01

    Interleukin 1beta (IL-1beta)-induced beta cell cytotoxicity has been implicated in the autoimmune cytotoxicity of insulin-dependent diabetes mellitus. These cytotoxic effects may be mediated by nitric oxide (NO). Since long-chain fatty acids (FFA), like IL-1beta, upregulate inducible nitric oxide synthase and enhance NO generation in islets, it seemed possible that islets might be protected from IL-1beta-induced damage by lowering their lipid content. We found that IL-1beta-induced NO production varied directly and islet cell viability inversely with islet triglyceride (TG) content. Fat-laden islets of obese rats were most vulnerable to IL-1beta, while moderately fat-depleted islets of food-restricted normal rats were less vulnerable than those of free-feeding normal rats. Severely lipopenic islets of rats made chronically hyperleptinemic by adenoviral leptin gene transfer resisted IL-1beta cytotoxicity even at 300 pg/ml, the maximal concentration. Troglitazone lowered islet TG in cultured islets from both normal rats and obese, leptin-resistant rats and reduced NO production and enhanced cell survival. We conclude that measures that lower islet TG content protect against IL-1beta-induced NO production and cytotoxicity. Leptin or troglitazone could provide in vivo protection against insulin-dependent diabetes mellitus. PMID:9312173

  12. A Nonhematopoietic Erythropoietin Analogue, ARA 290, Inhibits Macrophage Activation and Prevents Damage to Transplanted Islets.

    PubMed

    Watanabe, Masaaki; Lundgren, Torbjörn; Saito, Yu; Cerami, Anthony; Brines, Michael; Östenson, Claes-Göran; Kumagai-Braesch, Makiko

    2016-03-01

    Erythropoietin exerts anti-inflammatory, antiapoptotic, and cytoprotective effects in addition to its hematopoietic action. A nonhematopoietic erythropoietin analogue, ARA 290, has similar properties. The efficacy of pancreatic islet transplantation (PITx) is reduced due to islet damage that occurs during isolation and from the severe inflammatory reactions caused by the transplantation procedure. We investigated whether ARA 290 protects islets and ameliorates inflammatory responses following PITx thus improving engraftment. The effects of ARA 290 on pancreatic islets of C57BL/6J (H-2) mice and on murine macrophages were investigated using an in vitro culture model. As a marginal PITx, 185 islets were transplanted into the liver of streptozotocin-induced diabetic mice (H-2) via the portal vein. Recipients were given ARA 290 (120 μg/kg) intraperitoneally just before and at 0, 6, and 24 hours after PITx. Liver samples were obtained at 12 hours after PITx, and expression levels of proinflammatory cytokines were assessed. ARA 290 protected islets from cytokine-induced damage and apoptosis. Secretion of pro-inflammatory cytokines (IL-6, IL-12, and TNF-α) from macrophages was significantly inhibited by ARA 290. After the marginal PITx, ARA 290 treatment significantly improved the blood glucose levels when compared to those of control animals (P < 0.001). Upregulation of monocyte chemoattractant protein-1, macrophage inflammatory protein-1β, IL-1β, and IL-6 messenger RNA expression within the liver was suppressed by ARA 290 treatment. ARA 290 protected pancreatic islets from cytokine-induced damage and apoptosis and ameliorated the inflammatory response after PITx. ARA 290 appears to be a promising candidate for improvement of PITx.

  13. Expression of Innate Immunity Genes and Damage of Primary Human Pancreatic Islets by Epidemic Strains of Echovirus: Implication for Post-Virus Islet Autoimmunity

    PubMed Central

    Sarmiento, Luis; Frisk, Gun; Anagandula, Mahesh; Cabrera-Rode, Eduardo; Roivainen, Merja; Cilio, Corrado M.

    2013-01-01

    Three large-scale Echovirus (E) epidemics (E4,E16,E30), each differently associated to the acute development of diabetes related autoantibodies, have been documented in Cuba. The prevalence of islet cell autoantibodies was moderate during the E4 epidemic but high in the E16 and E30 epidemic. The aim of this study was to evaluate the effect of epidemic strains of echovirus on beta-cell lysis, beta-cell function and innate immunity gene expression in primary human pancreatic islets. Human islets from non-diabetic donors (n = 7) were infected with the virus strains E4, E16 and E30, all isolated from patients with aseptic meningitis who seroconverted to islet cell antibody positivity. Viral replication, degree of cytolysis, insulin release in response to high glucose as well as mRNA expression of innate immunity genes (IFN-b, RANTES, RIG-I, MDA5, TLR3 and OAS) were measured. The strains of E16 and E30 did replicate well in all islets examined, resulting in marked cytotoxic effects. E4 did not cause any effects on cell lysis, however it was able to replicate in 2 out of 7 islet donors. Beta-cell function was hampered in all infected islets (P<0.05); however the effect of E16 and E30 on insulin secretion appeared to be higher than the strain of E4. TLR3 and IFN-beta mRNA expression increased significantly following infection with E16 and E30 (P<0.033 and P<0.039 respectively). In contrast, the expression of none of the innate immunity genes studied was altered in E4-infected islets. These findings suggest that the extent of the epidemic-associated islet autoimmunity may depend on the ability of the viral strains to damage islet cells and induce pro-inflammatory innate immune responses within the infected islets. PMID:24223733

  14. Pancreatic islet-specific overexpression of Reg3β protein induced the expression of pro-islet genes and protected the mice against streptozotocin-induced diabetes mellitus.

    PubMed

    Xiong, Xiaoquan; Wang, Xiao; Li, Bing; Chowdhury, Subrata; Lu, Yarong; Srikant, Coimbatore B; Ning, Guang; Liu, Jun-Li

    2011-04-01

    Reg family proteins have been implicated in islet β-cell proliferation, survival, and regeneration. The expression of Reg3β (pancreatitis-associated protein) is highly induced in experimental diabetes and acute pancreatitis, but its precise role has not been established. Through knockout studies, this protein was shown to be mitogenic, antiapoptotic, and anti-inflammatory in the liver and pancreatic acinars. To test whether it can promote islet cell growth or survival against experimental damage, we developed β-cell-specific overexpression using rat insulin I promoter, evaluated the changes in normal islet function, gene expression profile, and the response to streptozotocin-induced diabetes. Significant and specific overexpression of Reg3β was achieved in the pancreatic islets of RIP-I/Reg3β mice, which exhibited normal islet histology, β-cell mass, and in vivo and in vitro insulin secretion in response to high glucose yet were slightly hyperglycemic and low in islet GLUT2 level. Upon streptozotocin treatment, in contrast to wild-type littermates that became hyperglycemic in 3 days and lost 15% of their weight, RIP-I/Reg3β mice were significantly protected from hyperglycemia and weight loss. To identify specific targets affected by Reg3β overexpression, a whole genome DNA microarray on islet RNA isolated from the transgenic mice revealed more than 45 genes significantly either up- or downregulated. Among them, islet-protective osteopontin/SPP1 and acute responsive nuclear protein p8/NUPR1 were significantly induced, a result further confirmed by real-time PCR, Western blots, and immunohistochemistry. Our results suggest that Reg3β is unlikely an islet growth factor but a putative protector that prevents streptozotocin-induced damage by inducing the expression of specific genes.

  15. Augmented damage of islets by impaired exocrine acinar cells undergoing apoptosis that is possibly converted to necrosis during isolation.

    PubMed

    Elgendy, Hamed; Okitsu, Teru; Kimura, Yasuko; Liu, Xibao; Nafady-Hego, Hanaa; Kurata, Jiro; Teramae, Hiroki; Elbahrawy, Ashraf; Uemoto, Shinji; Fukuda, Kazuhiko

    2011-01-01

    Islet damage attributed to impaired exocrine cells during pancreas preservation and isolation procedure remains elusive, although released exocrine enzymes could directly damage islets. The aim of this study is to investigate the cellular mechanisms associated with exocrine cells and their possible impact on the islet cell survival and function after isolation. Mouse pancreata were stored in cold University of Wisconsin preservation solution for 0, 24 and 48 h and incubated with or without collagenase at 37°C for 15 min. During preservation, the percentage of exocrine cells with necrosis, which means impaired cellular membrane that allows intracellular enzymes to be released, remains low (< 10%) regardless of preservation time; whereas the percentage of exocrine cells with apoptosis, which means impaired nucleus and possible intact cellular membrane, increases over time of preservation. After collagenase-free incubation, however, the percentage of exocrine cells with necrosis became higher in longer preservation time, and more than 60% of the necrotic exocrine cells contained apoptosis as well. Islet cells located in pancreata with intact structure are almost kept away either from necrotic or apoptotic changes even after 48 h preservation followed by collagenase-free incubation. However, when islets are isolated after collagenase-containing incubation, the percentage of islet cells with necrosis increases over time of preservation up to approximately 40%. This study suggests that exocrine cells with necrosis could cause damage of isolated islets when the pancreas is dissociated and that the necrosis in exocrine cells might be induced mainly as the conversion from apoptosis that has already existed during preservation.

  16. Assessment of benzene induced oxidative impairment in rat isolated pancreatic islets and effect on insulin secretion.

    PubMed

    Bahadar, Haji; Maqbool, Faheem; Mostafalou, Sara; Baeeri, Maryam; Rahimifard, Mahban; Navaei-Nigjeh, Mona; Abdollahi, Mohammad

    2015-05-01

    Benzene (C6H6) is an organic compound used in petrochemicals and numerous other industries. It is abundantly released to our environment as a chemical pollutant causing widespread human exposure. This study mainly focused on benzene induced toxicity on rat pancreatic islets with respect to oxidative damage, insulin secretion and glucokinase (GK) activity. Benzene was dissolved in corn oil and administered orally at doses 200, 400 and 800mg/kg/day, for 4 weeks. In rats, benzene significantly raised the concentration of plasma insulin. Also the effect of benzene on the release of glucose-induced insulin was pronounced in isolated islets. Benzene caused oxidative DNA damage and lipid peroxidation, and also reduced the cell viability and total thiols groups, in the islets of exposed rats. In conclusion, the current study revealed that pancreatic glucose metabolism is susceptible to benzene toxicity and the resultant oxidative stress could lead to functional abnormalities in the pancreas.

  17. Effect of Amorphophallus Konjac oligosaccharides on STZ-induced diabetes model of isolated islets.

    PubMed

    Lu, Xiu-Ju; Chen, Xiu-Min; Fu, De-Xian; Cong, Wei; Ouyang, Fan

    2002-12-27

    Three oligosaccharide fractions from the root of Amorphophallus Konjac, which was reported with hypoglycemic effects on diabetes subjects, were isolated and studied using the STZ-treated diabetes model. Among them, one fraction named as KOS-A, was found with nitric oxide (NO(*)) free radical regulation effect, while the other two were not. At concentrations less than 1.5 mM, KOS-A positively decreased STZ-induced NO(*) level of islets, but normal NO(*) release for non-STZ-treated islets was not affected within the range. At 15 mM, KOS-A played a contrary role and increased NO(*) level for islets both with and without STZ-treatment. Islets insulin secretion changed corresponding to NO(*) level in the assay. Increased insulin secretion appeared parallel to the decrease of NO(*), and normal insulin release was not affected by KOS-A less than 1.5 mM. Structure determination of KOS-A shows that it is a tetrasaccharide with Mw of 666 Da and reductive end of alpha-D-mannose. These results indicate that low dosage of KOS-A, with its function on attenuating STZ-induced NO(*) level, doesn't alter normal NO(*) and insulin secretion pathways of isolated islets. The NO(*) attenuation function of KOS-A on the diabetes model is mainly resulted from environmental free radical scavenging by the oligosaccharide. Present results also imply the mechanism of clinical Amorphophallus Konjac hypoglycemic function maybe related with free radical attenuation and lower risks of islets damage from NO(*) radical.

  18. The effects of oral carvacrol treatment against H2O2 induced injury on isolated pancreas islet cells of rats.

    PubMed

    Dagli Gul, Asli San; Fadillioglu, Ersin; Karabulut, Ismail; Yesilyurt, Ahmet; Delibasi, Tuncay

    2013-01-01

    Pancreatic islet transplantation is an alternative treatment of insulin replacement therapy in diabetes mellitus, but the islets are exposed to many chemical, mechanical damages, and oxidative stress before transplantation. Carvacrol is a well-known essential oil for its antioxidant, antimicrobial, antifungal and antiinflammatory properties. The aim of this study was to investigate the possible protective effects of carvacrol against H 2O 2 induced cellular injury on isolated pancreas islets. After carvacrol (20, 40 and 80 mg/kg/day) treatment, the pancreas islets were isolated by enzyme digestion. The isolated islets were incubated within 0, 150 and 300 µM H 2O 2 containing medium at +4°C for 15 min. Then, the islets were examined with fluorescein diacetate and propidium iodide mixture stains for viability. A number of islets were stored for lipid peroxidation, protein oxidation and DNA fragmentation analysis. The cell viability ratio of Carvacrol 20 mg/kg/day group was increased in comparison to control and vehicle (DMSO) groups. Additionally, carvacrol application protected the cells from lipid peroxidation and protein oxidation induced by H 2O 2. H 2O 2 caused tissue injury and DNA fragmentation. There was only one DNA fragmentation band from islet cells of 20 mg/kg/day carvacrol treated group, however there were more than one bands from control and DMSO groups. In conclusion, carvacrol treatment ameliorates islet cell injury induced by H 2O 2. However, the dose of carvacrol is important and our results suggest that 20 mg/kg/day dose is more effective than doses of 40 or 80 mg/kg/day.

  19. Impairment of glucose-induced insulin secretion in human pancreatic islets transplanted to diabetic nude mice.

    PubMed

    Jansson, L; Eizirik, D L; Pipeleers, D G; Borg, L A; Hellerström, C; Andersson, A

    1995-08-01

    Hyperglycemia-induced beta-cell dysfunction may be an important component in the pathogenesis of non-insulin-dependent diabetes mellitus. However, most available data in this field were obtained from rodent islets. To investigate the relevance of this hypothesis for human beta-cells in vivo, human pancreatic islets were transplanted under the renal capsule of nude mice. Experimental groups were chosen so that grafted islets were exposed to either hyper- or normoglycemia or combinations of these for 4 or 6 wk. Grafts of normoglycemic recipients responded with an increased insulin release to a glucose stimulus during perfusion, whereas grafts of hyperglycemic recipients failed to respond to glucose. The insulin content of the grafts in the latter groups was only 10% of those observed in controls. Recipients initially hyperglycemic (4 wk), followed by 2 wk of normoglycemia regained a normal graft insulin content, but a decreased insulin response to glucose remained. No ultrastructural signs of beta-cell damage were observed, with the exception of increased glycogen deposits in animals hyperglycemic at the time of killing. It is concluded that prolonged exposure to a diabetic environment induces a long-term secretory defect in human beta-cells, which is not dependent on the size of the islet insulin stores.

  20. Impairment of glucose-induced insulin secretion in human pancreatic islets transplanted to diabetic nude mice.

    PubMed Central

    Jansson, L; Eizirik, D L; Pipeleers, D G; Borg, L A; Hellerström, C; Andersson, A

    1995-01-01

    Hyperglycemia-induced beta-cell dysfunction may be an important component in the pathogenesis of non-insulin-dependent diabetes mellitus. However, most available data in this field were obtained from rodent islets. To investigate the relevance of this hypothesis for human beta-cells in vivo, human pancreatic islets were transplanted under the renal capsule of nude mice. Experimental groups were chosen so that grafted islets were exposed to either hyper- or normoglycemia or combinations of these for 4 or 6 wk. Grafts of normoglycemic recipients responded with an increased insulin release to a glucose stimulus during perfusion, whereas grafts of hyperglycemic recipients failed to respond to glucose. The insulin content of the grafts in the latter groups was only 10% of those observed in controls. Recipients initially hyperglycemic (4 wk), followed by 2 wk of normoglycemia regained a normal graft insulin content, but a decreased insulin response to glucose remained. No ultrastructural signs of beta-cell damage were observed, with the exception of increased glycogen deposits in animals hyperglycemic at the time of killing. It is concluded that prolonged exposure to a diabetic environment induces a long-term secretory defect in human beta-cells, which is not dependent on the size of the islet insulin stores. Images PMID:7635965

  1. AMT, an inducible nitric oxide synthase inhibitor, enhances islet engraftment.

    PubMed

    Chen, Y-T; Fu, S-H; Chen, J-P; Hsu, B R-S

    2009-06-01

    We co-transplanted silica gel-entrapping 4H-1,3-Thiazin-2-amine,5,6-dihydro-6-methyl monohydrochloride (AMT) with islets to evaluate the effects of AMT on early graft dysfunction in a syngeneic mouse model. The mean diameter of AMT-embedding silica gel particles was 595 +/- 275 nm. The cumulative release of AMT was 29% at 1 hour and 45% at 72 hours. Sixteen streptozotocin-induced diabetic mice were separated into 3 groups. Group A received 50 islets (n = 4). Group B received 50 islets and blank silica gel (n = 6). Group C received 50 islets plus silica-gel containing 6.4 microg AMT (n = 6). Mice in group C required significantly less time for temporary posttransplantation hyperglycemia than those in groups A and B (A, 39 +/- 7 vs B, 40 +/- 5 vs C, 24 +/- 2 days; P < .05). The insulin contents of grafts retrieved at 13 weeks were 1.17 +/- 0.11 (n = 4), 1.01 +/- 0.16 (n = 6), and 1.68 +/- 0.30 microg (n = 6) for mice in groups A, B, and C, respectively. Pancreatic remnant insulin did not differ significantly between the 3 groups (A, 0.32 +/- 0.04 [n = 4] vs B, 0.29 +/- 0.06 [n = 6] vs C, 0.40 +/- 0.05 microg [n = 6]; P > .05). In vitro study revealed that 4 and 20 nmol/L of sol-gel-embedded AMT protected 87% and 96% RIN-m5F cells from 1 ng/mL interleukin-1beta-mediated destruction, respectively. Silica-gel-entrapped AMT protects islet graft from a nonspecific inflammatory destruction, which is partly mediated via interleukin-1beta.

  2. Vitexin alleviates lipopolysaccharide-induced islet cell injury by inhibiting HMGB1 release

    PubMed Central

    Wang, Feifei; Yin, Jiajing; Ma, Yujin; Jiang, Hongwei; Li, Yanbo

    2017-01-01

    Diabetes mellitus (DM) is a chronic metabolic disease, where the predominant pathogenesis is pancreatic β-cells dysfunction or injury. It has been well established that inflammation leads to a gradual exhaustion of pancreatic β-cell function with decreased β-cell mass likely resulting from pancreatic β-cells apoptosis or death. Vitexin, a major bioactive flavonoid compound in plants has numerous pharmacological properties, including antioxidant, anti-inflammatory and antimyeloperoxidase. Whether vitexin can protect pancreatic β-cells against lipopolysaccharide (LPS)-induced pro-inflammatory cytokine production and apoptosis has received little attention. The present study investigated the potential effects of vitexin on LPS-induced pancreatic β-cell injury and apoptosis. It was revealed that apoptosis and damage induced by LPS in islet tissue of rats and INS-1 cells was significantly decreased in response to vitexin treatment. In addition, pretreatment with vitexin decreased the levels of the pro-inflammatory cytokines tumor necrosis factor-α and high mobility group box 1 (HMGB1) in LPS-induced rats. Further experiments demonstrated that vitexin pretreatment suppressed the activation of P38 mitogen-activated protein kinase signaling pathways in LPS-induced INS-1 cells. In conclusion, the results indicated that vitexin prevented LPS-induced islet tissue damage in rats, and INS-1 cells injury and apoptosis by inhibiting HMGB1 release. Therefore, the present study provided clear evidence indicating that vitexin may be a viable therapeutic strategy for the treatment of DM. PMID:28098903

  3. The Spleen Is an Ideal Site for Inducing Transplanted Islet Graft Expansion in Mice

    PubMed Central

    Takahashi, Hiroyuki; Kodama, Shohta

    2017-01-01

    Alternative islet transplantation sites have the potential to reduce the marginal number of islets required to ameliorate hyperglycemia in recipients with diabetes. Previously, we reported that T cell leukemia homeobox 1 (Tlx1)+ stem cells in the spleen effectively regenerated into insulin-producing cells in the pancreas of non-obese diabetic mice with end-stage disease. Thus, we investigated the spleen as a potential alternative islet transplantation site. Streptozotocin-induced diabetic C57BL/6 mice received syngeneic islets into the portal vein (PV), beneath the kidney capsule (KC), or into the spleen (SP). The marginal number of islets by PV, KC, or SP was 200, 100, and 50, respectively. Some plasma inflammatory cytokine levels in the SP group were significantly lower than those of the PV group after receiving a marginal number of islets, indicating reduced inflammation in the SP group. Insulin contents were increased 280 days after islet transplantation compared with those immediately following transplantation (p<0.05). Additionally, Tlx1-related genes, including Rrm2b and Pla2g2d, were up-regulated, which indicates that islet grafts expanded in the spleen. The spleen is an ideal candidate for an alternative islet transplantation site because of the resulting reduced inflammation and expansion of the islet graft. PMID:28135283

  4. Ginsenoside Rg3 enhances islet cell function and attenuates apoptosis in mouse islets.

    PubMed

    Kim, S S; Jang, H J; Oh, M Y; Eom, D W; Kang, K S; Kim, Y J; Lee, J H; Ham, J Y; Choi, S Y; Wee, Y M; Kim, Y H; Han, D J

    2014-05-01

    The transplantation of isolated islets is thought to be an attractive approach for curative treatment of diabetes mellitus. Panax ginseng has been used in oriental countries for its pharmacologic effects, such as antidiabetic and antiinflammatory activities. 20(S)-ginsenoside Rg3 (Rg3), an active ingredient of ginseng saponins, has been reported to enhance insulin secretion-stimulating and antiapoptotic activities in pancreatic beta cells. We performed this study to examine the hypothesis that preoperative Rg3 administration can enhance islet cell function and antiapoptosis before islet transplantation. Balb/c mice were randomly divided into 2 groups according to the administration of Rg3 after islet isolation. Mouse islets were cultured in medium supplemented with or without Rg3. In vitro, islet viability and function were assessed. After treatment of islets with a cytokine cocktail (tumor necrosis factor α, interferon-γ, and interleukin-1β), cell viability, function, and apoptosis were assessed. Cell viability was similar between the 2 groups. Islets cultured in medium supplemented with Rg3 showed 2.3-fold higher glucose-induced insulin secretion than islets cultured in medium without Rg3. After treatment with a cytokine cocktail, glucose-induced insulin release, total insulin content of islets, and apoptosis were significantly improved in Rg3-treated islets compared with cytokine-treated islets. Cytokine-treated islets produced significantly higher levels of nitric oxide (NO) than islets treated with Rg3. These results suggest that preoperative Rg3 administration enhanced islet function before islet transplantation and attenuated both cytokine-induced damage associated with NO production and apoptosis. Rg3 administration might be a prospective management to enhanced islet function and ameliorate early inflammation after transplantation. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Protective efficacy of folic acid and vitamin B12 against nicotine-induced toxicity in pancreatic islets of the rat

    PubMed Central

    Bhattacharjee, Ankita; Prasad, Shilpi Kumari; Pal, Swagata; Maji, Bithin; Syamal, Alak Kumar; Banerjee, Arnab

    2015-01-01

    Although cigarette smoking is associated with insulin resistance and an increased risk for type 2 diabetes, few studies have examined the effect of nicotine on the adult endocrine pancreas. In this study, male Wister rats were treated with nicotine (3 mg/kg body weight/ day) with or without supplementation of folic acid (36 μg/kg body weight/day) or vitamin B12 (0.63 μg/kg body weight/day) alone or in combination. Fasting blood glucose, insulin and HBA1C level and different oxidative and anti-oxidative stress parameters were measured and pancreatic tissue sections were stained with eosin-haematoxylene. Data were analysed by nonparametric statistics. The results revealed that nicotine induced prediabetes condition with subsequent damage to pancreatic islets in rats. Nicotine also caused oxidative stress in pancreatic tissue as evidenced by increased nitric oxide and malondialdehyde level and decreased superoxide dismutase, catalase and reduced glutathione level. Compared to vitamin B12 supplementation, folic acid blunted the nicotine-induced toxicity in pancreatic islets with higher efficacy. Further, folic acid and vitamin B12 in combination were able to confer significant protection on pancreatic islets against nicotine induced toxicity. These results suggest that supplementation of folic acid and vitamin B12 in combination may be a possible strategy of detoxification against nicotine-induced toxicity in pancreatic islets of the rat. PMID:27486368

  6. Membrane Permeation Induced by Aggregates of Human Islet Amyloid Polypeptides

    PubMed Central

    Poojari, Chetan; Xiao, Dequan; Batista, Victor S.; Strodel, Birgit

    2013-01-01

    Several neurodegenerative diseases such as Alzheimer’s and Parkinson’s diseases as well as nonneuropathic diseases such as type II diabetes and atrial amyloidosis are associated with aggregation of amyloid polypeptides into fibrillar structures, or plaques. In this study, we use molecular dynamics simulations to test the stability and orientation of membrane-embedded aggregates of the human islet amyloid polypeptide (hIAPP) implicated in type II diabetes. We find that in both monolayers and bilayers of dipalmitoylphosphatidylglycerol (DPPG) hIAPP trimers and tetramers remain inside the membranes and preserve their β-sheet secondary structure. Lipid bilayer-inserted hIAPP trimers and tetramers orient inside DPPG at 60° relative to the membrane/water interface and lead to water permeation and Na+ intrusion, consistent with ion-toxicity in islet β-cells. In particular, hIAPP trimers form a water-filled β-sandwich that induce water permeability comparable with channel-forming proteins, such as aquaporins and gramicidin-A. The predicted disruptive orientation is consistent with the amphiphilic properties of the hIAPP aggregates and could be probed by chiral sum frequency generation (SFG) spectroscopy, as predicted by the simulated SFG spectra. PMID:24268144

  7. Pregnancy restores insulin secretion from pancreatic islets in cafeteria diet-induced obese rats.

    PubMed

    Vanzela, E C; Ribeiro, R A; de Oliveira, C A Machado; Rodrigues, F B; Bonfleur, M L; Carneiro, E M; Souza, K L A; Boschero, A C

    2010-02-01

    Insulin resistance during pregnancy is counteracted by enhanced insulin secretion. This condition is aggravated by obesity, which increases the risk of gestational diabetes. Therefore, pancreatic islet functionality was investigated in control nonpregnant (C) and pregnant (CP), and cafeteria diet-fed nonpregnant (Caf), and pregnant (CafP) obese rats. Isolated islets were used for measurements of insulin secretion (RIA), NAD(P)H production (MTS), glucose oxidation ((14)CO(2) production), intracellular Ca(2+) levels (fura-2 AM), and gene expression (real-time PCR). Impaired glucose tolerance was clearly established in Caf and CafP rats at the 14th wk on a diet. Insulin secretion induced by direct depolarizing agents such as KCl and tolbutamide and increasing concentrations of glucose was significantly reduced in Caf, compared with C islets. This reduction was not observed in islets from CP and CafP rats. Accordingly, the glucose oxidation and production of reduced equivalents were increased in CafP islets. The glucose-induced Ca(2+) increase was significantly lower in Caf and higher in CafP, compared with all other groups. CP and CafP islets demonstrated an increased Ca(2+) oscillation frequency, compared with both C and Caf islets, and the amplitude of oscillations was augmented in CafP, compared with Caf islets. In addition, Ca(v)alpha1.2 and SERCA2a mRNA levels were reduced in Caf islets. Ca(v)alpha1.2, but not SERCA2a, mRNA was normalized in CafP islets. In conclusion, cafeteria diet-induced obesity impairs insulin secretion. This alteration is related to the impairment of Ca(2+) handling in pancreatic islets, in especial Ca(2+) influx, a defect that is reversed during pregnancy allowing normalization of insulin secretion.

  8. Virus-induced alterations in insulin release in hamster islets of Langerhans.

    PubMed

    Rayfield, E J; Seto, Y; Walsh, S; McEvoy, R C

    1981-11-01

    After the inoculation of Golden Syrian hamsters with the TC-83 vaccine strain of Venezuelan encephalitis (VE) virus, a sustained diminution in glucose-stimulated insulin release and glucose intolerance of shorter duration develops. To understand better the mechanism of this defect in insulin release, we examined insulin secretion in response to several test agents in isolated perifused islets from control and 24-d post-VE virus-infected hamsters. 50 islets were used in all perifusion experiments, and data were expressed as total insulin released as well as peak response for each test agent during a 30-min perifusion period from control and VE-infected islets. After perifusion with 20 mM glucose, a 45% diminution of insulin release was noted in VE-infected islets in comparison with control islets, which in turn was similar to in vivo findings. However, following 1-mM tolbutamide stimulation, insulin release was similar in control and VE-infected islets. In separate studies, 1 mM tolbutamide, 10 mM theophilline, 1 mM dibutyryl cyclic (c)AMP, and 1 mM 8-bromo-cAMP resulted in statistically similar insulin-release curves in control and VE-infected islets. Additional experiments assessing [5-3H]glucose use in control and infected islets after 20 min of perifusion with 20 mM glucose revealed virtually identical values (239 +/- 30-control; and 222 +/- 27-VE-infected islets). Morphological and morphometric evaluation of VE-infected islets (21 d following virus inoculation) showed no changes in islet volume density, beta cell density, and beta cell granulation. Thus, VE virus induces a defect in glucose-stimulated insulin release from hamster beta cells that can be corrected by cAMP analogues and does not alter islet glucose use.

  9. Beneficial effect of 17{beta}-estradiol on hyperglycemia and islet {beta}-cell functions in a streptozotocin-induced diabetic rat model

    SciTech Connect

    Yamabe, Noriko; Kang, Ki Sung; Zhu Baoting

    2010-11-15

    The modulating effect of estrogen on glucose homeostasis remains a controversial issue at present. In this study, we sought to determine the beneficial effect of 17{beta}-estradiol (E{sub 2}) on hyperglycemia and islet {beta}-cell functions in streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were injected i.p. with STZ to induce a relatively mild diabetic condition. The rats were then treated with E{sub 2} orally at 500 {mu}g/kg body weight/day for 15 days to evaluate the modulating effect on hyperglycemia, insulin secretion, and islet {beta}-cell proliferation. E{sub 2} administration for 10 days significantly lowered plasma glucose levels, increased plasma insulin levels, and improved glucose tolerance by attenuating insulin response to oral glucose loading. These beneficial effects of E{sub 2} were accompanied by increases in islet number and volume, rate of islet cell proliferation, and the amount of insulin secreted. The growth-stimulatory effect of E{sub 2} on islet cells was linked to the functions of the estrogen receptor {alpha}. Notably, these protective effects of E{sub 2} on diabetic conditions were basically not observed when the STZ-treated rats had a more severe degree of islet damage and hyperglycemia. Taken together, we conclude that E{sub 2} can promote the regeneration of damaged pancreatic islets by stimulating {beta}-cell proliferation in diabetic rats, and this effect is accompanied by improvements in glucose tolerance and a decrease in plasma glucose levels. These findings suggest that oral administration of E{sub 2} may be beneficial in diabetic patients with an accelerated loss of islet {beta}-cells.

  10. Red Ginseng Administration Before Islet Isolation Attenuates Apoptosis and Improves Islet Function and Transplant Outcome in a Syngeneic Mouse Marginal Islet Mass Model.

    PubMed

    Kim, J S; Jang, H J; Kim, S S; Oh, M Y; Kim, H J; Lee, S Y; Eom, D W; Ham, J Y; Han, D J

    2016-05-01

    Transplantation of isolated islets is a promising treatment for diabetes. Red ginseng (RG) is steamed ginseng and has been reported to enhance insulin secretion-stimulating and anti-apoptotic activities in pancreatic β-cells. In this study, we examined the hypothesis that pre-operative RG treatment enhances islet cell function and anti-apoptosis and investigated whether RG improves islet engraftment by transplant of a marginal mass of syngeneic islets pretreated with RG in diabetic mice. Balb/c mice were randomly divided into 2 groups, and 1 group was administered RG (400 mg/kg/day orally) for 7 days before islet isolation. In vitro islet viability and function were assessed. After cytokine treatment, cell viability, function, and apoptosis of islet cells were analyzed. Furthermore, we studied the effects of RG in a syngeneic islet graft model. A marginal mass of syngeneic mouse islets was transplanted into diabetic hosts. Islet pretreatment with RG showed 1.4-fold higher glucose-induced insulin secretion than did control islets. RG pretreatment upregulated B-cell lymphoma 2 (Bcl-2) expression and downregulated Bcl-associated X protein (BAX), caspase-3, and inducible nitric oxide synthase (iNOS) expression. Glucose-induced insulin release, NO, and apoptosis were significantly improved in RG-pretreated islets compared with cytokine-treated islets. RG-pretreated mice exhibited improved marginal mass islet graft survival compared with controls. These results suggest that pre-operative RG administration enhanced islet function before transplantation and attenuated cytokine-induced damage associated with apoptosis. These studies indicate that inhibition of apoptosis by RG significantly improved islet cell and graft function after isolation and transplantation, respectively. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Matrix Metalloproteinase-9 Protects Islets from Amyloid-induced Toxicity*

    PubMed Central

    Meier, Daniel T.; Tu, Ling-Hsien; Zraika, Sakeneh; Hogan, Meghan F.; Templin, Andrew T.; Hull, Rebecca L.; Raleigh, Daniel P.; Kahn, Steven E.

    2015-01-01

    Deposition of human islet amyloid polypeptide (hIAPP, also known as amylin) as islet amyloid is a characteristic feature of the pancreas in type 2 diabetes, contributing to increased β-cell apoptosis and reduced β-cell mass. Matrix metalloproteinase-9 (MMP-9) is active in islets and cleaves hIAPP. We investigated whether hIAPP fragments arising from MMP-9 cleavage retain the potential to aggregate and cause toxicity, and whether overexpressing MMP-9 in amyloid-prone islets reduces amyloid burden and the resulting β-cell toxicity. Synthetic hIAPP was incubated with MMP-9 and the major hIAPP fragments observed by MS comprised residues 1–15, 1–25, 16–37, 16–25, and 26–37. The fragments 1–15, 1–25, and 26–37 did not form amyloid fibrils in vitro and they were not cytotoxic when incubated with β cells. Mixtures of these fragments with full-length hIAPP did not modulate the kinetics of fibril formation by full-length hIAPP. In contrast, the 16–37 fragment formed fibrils more rapidly than full-length hIAPP but was less cytotoxic. Co-incubation of MMP-9 and fragment 16–37 ablated amyloidogenicity, suggesting that MMP-9 cleaves hIAPP 16–37 into non-amyloidogenic fragments. Consistent with MMP-9 cleavage resulting in largely non-amyloidogenic degradation products, adenoviral overexpression of MMP-9 in amyloid-prone islets reduced amyloid deposition and β-cell apoptosis. These findings suggest that increasing islet MMP-9 activity might be a strategy to limit β-cell loss in type 2 diabetes. PMID:26483547

  12. Progress in Clinical Encapsulated Islet Xenotransplantation.

    PubMed

    Cooper, David K C; Matsumoto, Shinichi; Abalovich, Adrian; Itoh, Takeshi; Mourad, Nizar I; Gianello, Pierre R; Wolf, Eckhard; Cozzi, Emanuele

    2016-11-01

    At the 2015 combined congress of the Cell Transplant Society, International Pancreas and Islet Transplant Association, and International Xenotransplantation Association, a symposium was held to discuss recent progress in pig islet xenotransplantation. The presentations focused on 5 major topics - (1) the results of 2 recent clinical trials of encapsulated pig islet transplantation, (2) the inflammatory response to encapsulated pig islets, (3) methods to improve the secretion of insulin by pig islets, (4) genetic modifications to the islet-source pigs aimed to protect the islets from the primate immune and/or inflammatory responses, and (5) regulatory aspects of clinical pig islet xenotransplantation. Trials of microencapsulated porcine islet transplantation to treat unstable type 1 diabetic patients have been associated with encouraging preliminary results. Further advances to improve efficacy may include (1) transplantation into a site other than the peritoneal cavity, which might result in better access to blood, oxygen, and nutrients; (2) the development of a more biocompatible capsule and/or the minimization of a foreign body reaction; (3) pig genetic modification to induce a greater secretion of insulin by the islets, and/or to reduce the immune response to islets released from damaged capsules; and (4) reduction of the inflammatory response to the capsules/islets by improvements in the structure of the capsules and/or in genetic engineering of the pigs and/or in some form of drug therapy. Ethical and regulatory frameworks for islet xenotransplantation are already available in several countries, and there is now a wider international perception of the importance of developing an internationally harmonized ethical and regulatory framework.

  13. Inhibition of instant blood-mediated inflammatory responses by co-immobilization of sCR1 and heparin on islets.

    PubMed

    Luan, Nguyen Minh; Iwata, Hiroo

    2013-07-01

    Intraportal transplantation of islets of Langerhans is followed by marked islet loss, mainly caused by instant blood-mediated inflammatory responses (IBMIR). We previously developed a method of co-immobilizing sCR1 and heparin on islets. Here we examined whether this process could reduce islet loss following intraportal islet transplantation in a syngeneic mouse model. sCR1-heparin islets or unmodified islet controls were transplanted into the livers of streptozotocin-induced diabetic mice. Transplantation of 100 and 125 sCR1-heparin islets normalized blood glucose levels in 8 of 9 (88.9%) and 9 of 9 diabetic mice (100%), respectively, whereas transplantation of 100 and 125 non-treated islets induced normoglycemia in 0 of 9 and 2 of 9 diabetic mice, respectively. Fibrin staining and plasma insulin measurements indicated that, compared to non-treated islets, sCR1-heparin islet transplantation was associated with fewer blood clots around islets, and significantly less insulin leakage from damaged islets at 1 h post-transplantation. Long-term follow-up of the sCR1-heparin islet group showed islet cells in the livers and insulin expression. In conclusion, co-immobilization of sCR1 and heparin on islets could effectively reduce islet damage by IBMIR, and might be useful to enable transplantation with only one donor and one recipient.

  14. Short-term high-fat feeding induces islet macrophage infiltration and β-cell replication independently of insulin resistance in mice.

    PubMed

    Woodland, David C; Liu, Wei; Leong, Jacky; Sears, Mallory L; Luo, Ping; Chen, Xiaojuan

    2016-10-01

    Short-term high-fat consumption stimulates mouse islet β-cell replication through unknown mechanisms. Resident macrophages (MΦs) are capable of secreting various factors involved in islet development and tissue remodeling. We hypothesized that a short-term high-fat diet (HFD) promotes MΦ infiltration in pancreatic islets and that MΦs serve as a regulator of β-cell replication. To test these hypotheses and dissect mechanisms involved in HFD-induced β-cell replication, adult C57BL/6J mice were fed a HFD for 7 days with or without administration of clodronate-containing liposomes, an MΦ-depleting agent. Mouse body and epididymal fat pad weights, and nonfasting blood glucose and fasting serum insulin levels were measured, and pancreatic islet β-cell replication, oxidative stress, and MΦ infiltration were examined. Short-term HFD promoted an increase in body and epididymal fat pad weight and blood glucose levels, along with an increased fasting serum insulin concentration. β-Cell replication, islet MΦ infiltration, and the percentage of inducible NO synthase positive MΦs in the islets increased significantly in mice fed the HFD. Immunofluorescence staining for 8-oxo-2'-deoxyguanosine or activated caspase-3 revealed no significant induction of DNA damage or apoptosis, respectively. In addition, no change in stromal-derived factor 1-expressing cells was found induced by HFD. Despite continuous elevation of nonfasting blood glucose and fasting serum insulin levels, depletion of MΦs through treatments of clodronate abrogated HFD-induced β-cell replication. These findings demonstrated that HFD-induced MΦ infiltration is responsible for β-cell replication. This study suggests the existence of MΦ-mediated mechanisms in β-cell replication that are independent of insulin resistance. Copyright © 2016 the American Physiological Society.

  15. The effects of microencapsulation on pancreatic islet osmotically induced volumetric response.

    PubMed

    Woods, E J; Liu, J; Zieger, M A; Lakey, J R; Critser, J K

    1999-01-01

    were reached within 30-40 s after exposure to the cryoprotectant. Encapsulated human islets reached 86.88 +/- 1.47% of their original volume in 2 M and 80.33 +/- 0.89% in 3 M DMSO, and 87.33 +/- 1.86% in 2 M and 82.80 +/- 1.57% in 3 M EG. This volume change was significantly less (p < 0.01) than that observed in corresponding free islets. Encapsulated canine islets reached 83.67 +/- 2.13% of their original volume in 2 M and 78.22 +/- 0.95% in 3 M DMSO, and 85.44 +/- 1.92% in 2 M and 78.11 +/- 2.01% in 3 M EG. As with human islets, this was significantly different than free islets (p < 0.01). These minimal volumes were reached within 30-50 s. These results demonstrate that there are cryoprotectant and alginate-specific interactions and that microencapsulation modulates the degree of osmotically induced shrinkage of islets. The development or modification of existing cryopreservation protocols to improve postcryopreservation recovery or function must account for these factors.

  16. Islet neogenesis associated protein transgenic mice are resistant to hyperglycemia induced by streptozotocin.

    PubMed

    Taylor-Fishwick, David A; Bowman, Angela; Hamblet, Natasha; Bernard, Paul; Harlan, David M; Vinik, Aaron I

    2006-09-01

    Islet neogenesis associated protein (INGAP) is a protein factor that can stimulate new islet mass from adult pancreatic progenitor cells. In models of islet neogenesis, INGAP expression is elevated in pancreatic acinar cells. Using a transgenic model to drive a sustained expression of INGAP in pancreatic acinar cells, we have identified a protection to chemical-induced hyperglycemia. A sustained expression of INGAP during development did not perturb islet development or basal blood glucose homeostasis, although beta-cell mass and pancreatic insulin content were significantly increased in the INGAP transgenic mice. When challenged with a diabetogenic dose of streptozotocin (STZ), mice carrying the INGAP transgene did not become hyperglycemic. In contrast, wild-type mice became and remained hyperglycemic, blood glucose > 550 mg/dl. The serum insulin levels and islet morphology were preserved in the transgenic mice after STZ treatment. These data suggest that the sustained expression of INGAP in the acinar pancreas confers resistance to a diabetogenic insult. The INGAP transgenic mouse provides a new model to uncover factors that are protective to diabetes onset and biomarkers to track beta-cell pathology.

  17. Inhibition of TLR4 protects rat islets against lipopolysaccharide-induced dysfunction.

    PubMed

    Wang, Xiao; Ge, Qin Min; Bian, Fan; Dong, Yan; Huang, Chun Mei

    2017-02-01

    Oxidative stress leads to dysfunction in pancreatic cells, causing a reduction in insulin secretion following exposure to glucose. Toll-like receptor 4 (TLR4) may be activated by exposure to lipopolysaccharide (LPS) stress. TLR4 may mediate the initiation of inflammatory and immune defense responses; however, the importance of the LPS/TLR4 interaction in apoptosis induced by oxidative stress in pancreatic β cells remains to be elucidated. The present study aimed to investigate the importance of TLR4 during LPS‑induced oxidative stress, apoptosis and dysfunction of insulin secretion in isolated islets of rats. LPS‑induced stimulation of TLR4 increased the production of reactive oxygen species and promoted apoptosis by upregulating the expression levels of caspase‑3, poly ADP ribose polymerase and altering the expression ratio of B‑cell lymphoma‑2 (Bcl‑2)/Bcl‑2 associated X protein. Additionally, the insulin secretion of islets cells was reduced. Anti‑TLR4 antibody and a knockdown of TLR4 by TLR4‑short hairpin RNA were used to inhibit TLR4 activity, which may reverse LPS‑induced events. The present study determined that in islets exposed to LPS oxidative stress, dysfunction may be partly mediated via the TLR4 pathway. Inhibition of TLR4 may prevent dysfunction of rat islets due to oxidative stress. The present study revealed that targeting the LPS/TLR4 signaling pathway and antioxidant therapy may be a novel treatment for the severely septic patients with hyperglycemia stress.

  18. IGF-I overexpression does not promote compensatory islet cell growth in diet-induced obesity.

    PubMed

    Robertson, Katie; Dong, Jing; De Jesus, Kristine; Liu, Jun-Li

    2010-02-01

    Although IGF-I was known to stimulate the growth of pancreatic islet cells from early in vitro experiments and in vivo reports on rodents, recent gene targeting experiments have indicated that IGF-I and its receptor do not play a major role in normal islet cell growth. In our previous reports, liver- or pancreatic-specific IGF-I deficiency caused no decrease in β-cell mass; a general and β-cell-enriched IGF-I overexpression caused no change in normal islet cell growth. On the other hand, increased metabolic demands (such as in obesity and insulin resistance) result in β-cell compensation in cell number and insulin secretion. In order to test whether IGF-I could promote islet cell growth and facilitate islet compensation due to obesity-induced insulin resistance, we have challenged MT-IGF mice to a high-fat diet. After 28 weeks, both MT-IGF mice and wild-type littermates gained comparable 40-57% of body weight, with similar increases in fat masses; all mice maintained a normal sensitivity to insulin and did not become severely hyperglycemic. Nevertheless, compared to wild-type littermates, the equally obese MT-IGF mice maintained improved glucose tolerance and a diminished insulin level; similar to when fed a normal chow diet. More importantly, under IGF-I overexpression, there was no further increase in β-cell mass caused by obesity. Thus, IGF-I overexpression had no significant effect on weight gain and islet cell compensation in response to high-fat diet-induced obesity.

  19. Niacin-induced hyperglycemia is partially mediated via niacin receptor GPR109a in pancreatic islets.

    PubMed

    Chen, Lihua; So, Wing Yan; Li, Stephen Y T; Cheng, Qianni; Boucher, Barbara J; Leung, Po Sing

    2015-03-15

    The widely used lipid-lowering drug niacin is reported to induce hyperglycemia during chronic and high-dose treatments, but the mechanism is poorly understood. Recently, the niacin receptor [G-protein-coupled receptor, (GPR) 109a], has been localized to islet cells while its potential role therein remains unclear. We, therefore, aimed at investigating how GPR109a regulates islet beta-cell function and its downstream signaling using high-fat diet-induced obese mice and INS-1E beta cells. Eight-week niacin treatment elevated blood glucose concentration in obese mice with increased areas under the curve at oral glucose and intraperitoneal insulin tolerance tests. Additionally, niacin treatment significantly decreased glucose-stimulated insulin secretion (GSIS) but induced peroxisome proliferator-activated receptor gamma (Pparg) and GPR109a expression in isolated pancreatic islets; concomitantly, reactive oxygen species (ROS) were transiently increased, with decreases in GSIS, intracellular cyclic adenosine monophosphate (cAMP) accumulation and mitochondrial membrane potential (ΔΨm), but with increased expression of uncoupling protein 2 (Ucp2), Pparg and Gpr109a in INS-1E cells. Corroborating these findings, the decreases in GSIS, ΔΨm and cAMP production and increases in ROS, Pparg and GPR109a expression were abolished in INS-1E cells by GPR109a knockdown. Our data indicate that niacin-induced pancreatic islet dysfunction is probably modulated through activation of the islet beta-cell GPR109a-induced ROS-PPARγ-UCP2 pathways.

  20. Par-4/NF-κB Mediates the Apoptosis of Islet β Cells Induced by Glucolipotoxicity

    PubMed Central

    QiNan, Wu; XiaGuang, Gan; XiaoTian, Lei; WuQuan, Deng; Ling, Zhang; Bing, Chen

    2016-01-01

    Apoptosis of islet β cells is a primary pathogenic feature of type 2 diabetes, and ER stress and mitochondrial dysfunction play important roles in this process. Previous research has shown that prostate apoptosis response-4 (Par-4)/NF-κB induces cancer cell apoptosis through endoplasmic reticulum (ER) stress and mitochondrial dysfunction. However, the mechanism by which Par-4/NF-κB induces islet β cell apoptosis remains unknown. We used a high glucose/palmitate intervention to mimic type 2 diabetes in vitro. We demonstrated that the high glucose/palmitate intervention induced the expression and secretion of Par-4. It also causes increased expression and activation of NF-κB, which induced NIT-1 cell apoptosis and dysfunction. Overexpression of Par-4 potentiates these effects, whereas downregulation of Par-4 attenuates them. Inhibition of NF-κB inhibited the Par-4-induced apoptosis. Furthermore, these effects occurred through the ER stress cell membrane and mitochondrial pathway of apoptosis. Our findings reveal a novel role for Par-4/NF-κB in islet β cell apoptosis and type 2 diabetes. PMID:27340675

  1. DNA Damage Induced Neuronal Death

    DTIC Science & Technology

    1999-10-01

    Experiments are proposed to examine the molecular mechanism by which mustard chemical warfare agents induce neuronal cell death . DNA damage is the...proposed underlying mechanism of mustard-induced neuronal cell death . We propose a novel research strategy to test this hypothesis by using mice with...perturbed DNA repair to explore the relationship between mustard-induced DNA damage and neuronal cell death . Initial in vitro studies (Years 1, 2 & 3

  2. Destruction of rat pancreatic islet beta-cells by cytokines involves the production of cytotoxic aldehydes.

    PubMed

    Suarez-Pinzon, W L; Strynadka, K; Rabinovitch, A

    1996-12-01

    Cytokines produced by mononuclear leukocytes infiltrating pancreatic islets are candidate mediators of islet beta-cell destruction in autoimmune insulin-dependent diabetes mellitus. Cytokines may damage islet beta-cells by inducing oxygen free radical production in the beta-cells. Lipid peroxidation and aldehyde production are measures of oxygen free radical-mediated cell injury. In the current study, we used a HPLC technique to measure levels of different aldehydes produced in rat islets incubated with cytokines. The cytokine combination of interleukin-1beta (10 U/ml), tumor necrosis factor-alpha (10(3) U/ml), and interferon-gamma (10(3) U/ml), and the oxidant, t-butylhydroperoxide, induced significant increases in islet levels of the same aldehydes: butanal, pentanal, 4-hydroxynonenal (4-HNE), and hexanal. Cytokine-induced aldehyde production was associated with islet beta-cell destruction. Thus, cytokine-induced increases in malondialdehyde (MDA; at 4 h) and 4-HNE (at 8 h) preceded islet cell destruction (at 16 h), and the addition of 4-HNE, hexanal, MDA, and pentanal (1-200 microM) to th islets, but not other aldehydes at similar concentrations, produced dose-dependent destruction of islet beta-cells. Furthermore, an antioxidant (lazaroid U78518E) prevented cytokine-induced increases in 4-HNE, hexanal, and MDA and significantly inhibited cytokine-induced decreases in insulin and DNA in the islets. In contrast, N(G)-monomethyl-L-arginine, an inhibitor of nitric oxide synthase, prevented cytokine-induced nitrite production, but did not prevent cytokine-induced increases in 4-HNE, hexanal, and MDA or decreases in insulin and DNA in the islets. These results suggest that cytokines may damage islet beta-cells by inducing oxygen free radicals, lipid peroxidation, and, consequently, the formation of cytotoxic aldehydes in the islet cells.

  3. Mechanisms of defective glucose-induced insulin release in human pancreatic islets transplanted to diabetic nude mice.

    PubMed

    Eizirik, D L; Jansson, L; Flodström, M; Hellerström, C; Andersson, A

    1997-08-01

    We have previously observed that human islets, transplanted under the kidney capsule of hyperglycemic nude mice, show a longlasting impairment in glucose-induced insulin release. To investigate the cause(s) of this phenomenon, we transplanted human islets into normoglycemic or alloxan-diabetic nude mice for a 4- to 6-week period. In a third experimental group, aimed at evaluating reversibility of hyperglycemia effects, diabetic nude mice bearing a human islet graft were cured by a second intrasplenic transplant of mouse islets, and the human islets were exposed to a further 2 weeks of normoglycemia. Four to 6 weeks of hyperglycemia induced a severe impairment of glucose- and arginine-induced insulin release, as demonstrated by perfusion of the graft-bearing kidney. This defective release was not restored by a subsequent 2-week period of normoglycemia, and it was accompanied by normal (pro)insulin biosynthesis, glucose oxidation, and expression of insulin messenger RNA. Taken together with our previous study, these observations indicate that impaired glucose metabolism, depletion of insulin messenger RNA, decreased (pro)insulin biosynthesis, increased glycogen accumulation, and depletion of insulin reserves cannot explain the deleterious effects of the diabetic state on human islet insulin release. This, and the similar inhibition of glucose- and arginine-induced insulin release, suggest that prolonged hyperglycemia may exert its deleterious effect on insulin release at a step distal to closure of ATP-sensitive K-channels.

  4. The TrxG Complex Mediates Cytokine Induced De Novo Enhancer Formation in Islets

    PubMed Central

    Hurley, Peter; Dhillon, Jasmine; Gill, Amol; Whiting, Cheryl

    2015-01-01

    To better understand how β-cells respond to proinflammatory cytokines we mapped the locations of histone 3 lysine 4 monomethylation (H3K4me1), a post-translational histone modification enriched at active and poised cis-regulatory regions, in IFNγ, Il-1β, and TNFα treated pancreatic islets. We identified 96,721 putative cis-regulatory loci, of which 3,590 were generated de novo, 3,204 had increased H3K4me1, and 5,354 had decreased H3K4me1 in IFNγ, Il-1β, and TNFα exposed islets. Roughly 10% of the de novo and increased regions were enriched for the repressive histone modification histone 3 lysine 27 trimethylation (H3K27me3) in untreated cells, and these were frequently associated with chemokine genes. We show that IFNγ, Il-1β, and TNFα exposure overcomes this repression and induces chemokine gene activation in as little as three hours, and that this expression persists for days in absence of continued IFNγ, Il-1β, and TNFα exposure. We implicate trithorax group (TrxG) complexes as likely players in the conversion of these repressed loci to an active state. To block the activity of these complexes, we suppressed Wdr5, a core component of the TrxG complexes, and used the H3K27me3 demethylase inhibitor GSK-J4. We show that GSK-J4 is particularly effective in blunting IFNγ, Il-1β, and TNFα-induced chemokine gene expression in β-cells; however, it induced significant islet-cell apoptosis and β-cell dysfunction. Wdr5 suppression also reduced IFNγ, Il-1β, and TNFα induced chemokine gene expression in β-cells without affecting islet-cell survival or β-cell function after 48hrs, but did begin to increase islet-cell apoptosis and β-cell dysfunction after four days of treatment. Taken together these data suggest that the TrxG complex is potentially a viable target for preventing cytokine induced chemokine gene expression in β-cells. PMID:26505193

  5. Proteasome Dysfunction Mediates High Glucose-Induced Apoptosis in Rodent Beta Cells and Human Islets

    PubMed Central

    Broca, Christophe; Varin, Elodie; Armanet, Mathieu; Tourrel-Cuzin, Cécile; Bosco, Domenico; Dalle, Stéphane; Wojtusciszyn, Anne

    2014-01-01

    The ubiquitin/proteasome system (UPS), a major cellular protein degradation machinery, plays key roles in the regulation of many cell functions. Glucotoxicity mediated by chronic hyperglycaemia is detrimental to the function and survival of pancreatic beta cells. The aim of our study was to determine whether proteasome dysfunction could be involved in beta cell apoptosis in glucotoxic conditions, and to evaluate whether such a dysfunction might be pharmacologically corrected. Therefore, UPS activity was measured in GK rats islets, INS-1E beta cells or human islets after high glucose and/or UPS inhibitor exposure. Immunoblotting was used to quantify polyubiquitinated proteins, endoplasmic reticulum (ER) stress through CHOP expression, and apoptosis through the cleavage of PARP and caspase-3, whereas total cell death was detected through histone-associated DNA fragments measurement. In vitro, we found that chronic exposure of INS-1E cells to high glucose concentrations significantly decreases the three proteasome activities by 20% and leads to caspase-3-dependent apoptosis. We showed that pharmacological blockade of UPS activity by 20% leads to apoptosis in a same way. Indeed, ER stress was involved in both conditions. These results were confirmed in human islets, and proteasome activities were also decreased in hyperglycemic GK rats islets. Moreover, we observed that a high glucose treatment hypersensitized beta cells to the apoptotic effect of proteasome inhibitors. Noteworthily, the decreased proteasome activity can be corrected with Exendin-4, which also protected against glucotoxicity-induced apoptosis. Taken together, our findings reveal an important role of proteasome activity in high glucose-induced beta cell apoptosis, potentially linking ER stress and glucotoxicity. These proteasome dysfunctions can be reversed by a GLP-1 analog. Thus, UPS may be a potent target to treat deleterious metabolic conditions leading to type 2 diabetes. PMID:24642635

  6. Pancreatic Islets Engineered with SA-FasL Protein Establish Robust Localized Tolerance by Inducing T Regulatory Cells in Mice

    PubMed Central

    Yolcu, Esma S; Zhao, Hong; Bandura-Morgan, Laura; Lacelle, Chantale; Woodward, Kyle B; Askenasy, Nadir; Shirwan, Haval

    2011-01-01

    Allogeneic islet transplantation is an important therapeutic approach for the treatment of T1D. Clinical application of this approach, however, is severely curtailed by allograft rejection primarily initiated by pathogenic T effector cells regardless of chronic use of immunosuppression. Given the role of Fas-mediated signaling in regulating T effector cell responses, we tested if pancreatic islets can be engineered ex vivo to display on their surface an apoptotic form of FasL protein chimeric with streptavidin (SA-FasL), and whether such engineered islets induce tolerance in allogeneic hosts. Islets were modified with biotin following efficient engineering with SA-FasL protein that persisted on the surface of islets for over a week in vitro. SA-FasL-engineered islet grafts established euglycemia in chemically diabetic syngeneic mice indefinitely, demonstrating functionality and lack of acute toxicity. Most importantly, the transplantation of SA-FasL-engineered BALB/c islet grafts in conjunction with a short course of rapamycin treatment resulted in robust localized tolerance in 100% C57BL/6 recipients. Tolerance was initiated and maintained by CD4+CD25+FoxP3+ T regulatory (Treg) cells as their depletion early during tolerance induction or late after established tolerance resulted in prompt graft rejection. Furthermore, Treg cells sorted from graft-draining lymph nodes, but not spleen, of long-term graft recipients prevented the rejection of unmodified allogeneic islets in an adoptive transfer model, further confirming the Treg role in established tolerance. Engineering islets ex vivo in a rapid and efficient manner to display on their surface immunomodulatory proteins represents a novel, safe, and clinically applicable approach with important implications for the treatment of T1D. PMID:22068235

  7. Pancreatic islets engineered with SA-FasL protein establish robust localized tolerance by inducing regulatory T cells in mice.

    PubMed

    Yolcu, Esma S; Zhao, Hong; Bandura-Morgan, Laura; Lacelle, Chantale; Woodward, Kyle B; Askenasy, Nadir; Shirwan, Haval

    2011-12-01

    Allogeneic islet transplantation is an important therapeutic approach for the treatment of type 1 diabetes. Clinical application of this approach, however, is severely curtailed by allograft rejection primarily initiated by pathogenic effector T cells regardless of chronic use of immunosuppression. Given the role of Fas-mediated signaling in regulating effector T cell responses, we tested if pancreatic islets can be engineered ex vivo to display on their surface an apoptotic form of Fas ligand protein chimeric with streptavidin (SA-FasL) and whether such engineered islets induce tolerance in allogeneic hosts. Islets were modified with biotin following efficient engineering with SA-FasL protein that persisted on the surface of islets for >1 wk in vitro. SA-FasL-engineered islet grafts established euglycemia in chemically diabetic syngeneic mice indefinitely, demonstrating functionality and lack of acute toxicity. Most importantly, the transplantation of SA-FasL-engineered BALB/c islet grafts in conjunction with a short course of rapamycin treatment resulted in robust localized tolerance in 100% of C57BL/6 recipients. Tolerance was initiated and maintained by CD4(+)CD25(+)Foxp3(+) regulatory T (Treg) cells, as their depletion early during tolerance induction or late after established tolerance resulted in prompt graft rejection. Furthermore, Treg cells sorted from graft-draining lymph nodes, but not spleen, of long-term graft recipients prevented the rejection of unmodified allogeneic islets in an adoptive transfer model, further confirming the Treg role in established tolerance. Engineering islets ex vivo in a rapid and efficient manner to display on their surface immunomodulatory proteins represents a novel, safe, and clinically applicable approach with important implications for the treatment of type 1 diabetes.

  8. Inflammatory Response in Islet Transplantation

    PubMed Central

    Kanak, Mazhar A.; Kunnathodi, Faisal; Lawrence, Michael C.; Levy, Marlon F.

    2014-01-01

    Islet cell transplantation is a promising beta cell replacement therapy for patients with brittle type 1 diabetes as well as refractory chronic pancreatitis. Despite the vast advancements made in this field, challenges still remain in achieving high frequency and long-term successful transplant outcomes. Here we review recent advances in understanding the role of inflammation in islet transplantation and development of strategies to prevent damage to islets from inflammation. The inflammatory response associated with islets has been recognized as the primary cause of early damage to islets and graft loss after transplantation. Details on cell signaling pathways in islets triggered by cytokines and harmful inflammatory events during pancreas procurement, pancreas preservation, islet isolation, and islet infusion are presented. Robust control of pre- and peritransplant islet inflammation could improve posttransplant islet survival and in turn enhance the benefits of islet cell transplantation for patients who are insulin dependent. We discuss several potent anti-inflammatory strategies that show promise for improving islet engraftment. Further understanding of molecular mechanisms involved in the inflammatory response will provide the basis for developing potent therapeutic strategies for enhancing the quality and success of islet transplantation. PMID:24883060

  9. Nigella sativa seed extracts enhance glucose-induced insulin release from rat-isolated Langerhans islets.

    PubMed

    Rchid, Halima; Chevassus, Hugues; Nmila, Rachid; Guiral, Carine; Petit, Pierre; Chokaïri, Mustapha; Sauvaire, Yves

    2004-10-01

    Nigella sativa L. 'Black cumin' (Ranunculaceae) is one of the plants commonly used in Moroccan folk medicine for treatment of various ailments including diabetes mellitus. The present study was undertaken to investigate the effect of different N. sativa seed extracts on insulin secretion. Different fractions of the seed were prepared: the defatted fraction (HR II), which was divided into two subfractions: the first (HR III) containing acidic and neutral compounds and the second (HR IV) containing basic compounds. The insulin secretory effects of these extracts were evaluated individually at different concentrations (0.01, 0.1, 1 and 5 mg/mL), in vitro in isolated rat pancreatic islets in the presence of 8.3 mmol/L glucose. The results show that addition of the defatted whole extract or of the basic subfraction of the seed in the incubation medium significantly increased glucose-induced insulin release from the islets. In the case of the acidic and neutral subfraction, the stimulatory effect was observed only for the higher concentration (5 mg/mL). However, a clear concentration-dependent increase in insulin release from isolated pancreatic islets was observed for the basic subfraction. Our data show that the antidiabetic properties of N. sativa seeds may be, at least partly, mediated by stimulated insulin release, and that the basic subfraction largely contributes to this stimulatory effect. Further phytochemical studies are underway in order to isolate the pharmacological compound(s) responsible for the insulinotropic effect of N. sativa seeds.

  10. Viral infection induces cytokine release by beta islet cells.

    PubMed Central

    Cavallo, M G; Baroni, M G; Toto, A; Gearing, A J; Forsey, T; Andreani, D; Thorpe, R; Pozzilli, P

    1992-01-01

    Viral infection has been suggested to play a triggering role in the pancreatic beta cell destruction which occurs in insulin-dependent diabetes (IDDM). However, the underlying mechanism of this phenomenon is unknown. In this study a human insulinoma cell line has been infected with measles, mumps and rubella viruses since a temporal association is reported between the clinical onset of IDDM and diseases caused by these viruses. The infection with measles and mumps viruses induced the release of interleukin-1 (IL-1) and interleukin-6 (IL-6) by the cell line as assessed by a bioassay and up-regulated the expression of human leucocyte antigen (HLA) class I and class II antigens as evaluated by cytofluorimetric analysis. Stimulation with rubella virus induced the release of IL-6 only and had no effect on HLA antigen expression. These data show for the first time that IL-1 and IL-6 secretion by an insulinoma cell line may occur after viral infection and suggest that cytokine release and increased expression of HLA molecules by beta cells may act to induce the immune response towards beta cells in IDDM. PMID:1592439

  11. Nardostachys jatamansi extract protects against cytokine-induced β-cell damage and streptozotocin-induced diabetes

    PubMed Central

    Song, Mi-Young; Bae, Ui-Jin; Lee, Bong-Hee; Kwon, Kang-Beom; Seo, Eun-A; Park, Sung-Joo; Kim, Min-Sun; Song, Ho-Joon; Kwon, Keun-Sang; Park, Jin-Woo; Ryu, Do-Gon; Park, Byung-Hyun

    2010-01-01

    AIM: To investigate the anti-diabetogenic mechanism of Nardostachys jatamansi extract (NJE). METHODS: Mice were injected with streptozotocin via a tail vein to induce diabetes. Rat insulinoma RINm5F cells and isolated rat islets were treated with interleukin-1β and interferon-γ to induce cytotoxicity. RESULTS: Treatment of mice with streptozotocin resulted in hyperglycemia and hypoinsulinemia, which was confirmed by immunohistochemical staining of the islets. The diabetogenic effects of streptozotocin were completely abolished when mice were pretreated with NJE. Inhibition of streptozotocin-induced hyperglycemia by NJE was mediated by suppression of nuclear factor (NF)-κB activation. In addition, NJE protected against cytokine-mediated cytotoxicity. Incubation of RINm5F cells and islets with NJE resulted in a significant reduction in cytokine-induced NF-κB activation and downstream events, inducible nitric oxide synthase expression and nitric oxide production. The protective effect of NJE was further demonstrated by the normal insulin secretion of cytokine-treated islets in response to glucose. CONCLUSION: NJE provided resistance to pancreatic β-cell damage from cytokine or streptozotocin treatment. The β-cell protective effect of NJE is mediated by suppressing NF-κB activation. PMID:20614480

  12. Adverse effect on syngeneic islet transplantation by transgenic coexpression of decoy receptor 3 and heme oxygenase-1 in the islet of NOD mice.

    PubMed

    Huang, S-H; Lin, G-J; Chien, M-W; Chu, C-H; Yu, J-C; Chen, T-W; Hueng, D-Y; Liu, Y-L; Sytwu, H-K

    2013-03-01

    Decoy receptor 3 (DcR3) blocks both Fas ligand- and LIGHT-induced pancreatic β-cell damage in autoimmune diabetes. Heme oxygenase 1 (HO-1) possesses antiapoptotic, anti-inflammatory, and antioxidative effects that protect cells against various forms of attack by the immune system. Previously, we have demonstrated that transgenic islets overexpressing DcR3 or murine HO-1 (mHO-1) exhibit longer survival times than nontransgenic islets in syngeneic islet transplantation. In this study, we evaluated whether DcR3 and mHO-1 double-transgenic islets of NOD mice could provide better protective effects and achieve longer islet graft survival than DcR3 or mHO-1 single-transgenic islets after islet transplantation. We generated DcR3 and mHO-1 double-transgenic NOD mice that specifically overexpress DcR3 and HO-1 in islets. Seven hundred islets isolated from double-transgenic, single-transgenic, or nontransgenic NOD mice were syngeneically transplanted into the kidney capsules of newly diabetic female recipients. Unexpectedly, there was no significant difference in the survival time between double-transgenic or nontransgenic NOD islet grafts, and the survival times of double-transgenic NOD islet grafts were even shorter than those of DcR3 or mHO-1 single-transgenic islets. Our data indicate that transplantation of double-transgenic islets that coexpress HO-1 and DcR3 did not result in a better outcome. On the contrary, this strategy even caused an adverse effect in syngeneic islet transplantation.

  13. Cholesterol reduction ameliorates glucose-induced calcium handling and insulin secretion in islets from low-density lipoprotein receptor knockout mice.

    PubMed

    Souza, J C; Vanzela, E C; Ribeiro, R A; Rezende, L F; de Oliveira, C A; Carneiro, E M; Oliveira, H C F; Boschero, A C

    2013-04-01

    Changes in cellular cholesterol level may contribute to beta cell dysfunction. Islets from low density lipoprotein receptor knockout (LDLR(-/-)) mice have higher cholesterol content and secrete less insulin than wild-type (WT) mice. Here, we investigated the association between cholesterol content, insulin secretion and Ca(2+) handling in these islets. Isolated islets from both LDLR(-/-) and WT mice were used for measurements of insulin secretion (radioimmunoassay), cholesterol content (fluorimetric assay), cytosolic Ca(2+) level (fura-2AM) and SNARE protein expression (VAMP-2, SNAP-25 and syntaxin-1A). Cholesterol was depleted by incubating the islets with increasing concentrations (0-10mmol/l) of methyl-beta-cyclodextrin (MβCD). The first and second phases of glucose-stimulated insulin secretion (GSIS) were lower in LDLR(-/-) than in WT islets, paralleled by an impairment of Ca(2+) handling in the former. SNAP-25 and VAMP-2, but not syntaxin-1A, were reduced in LDLR(-/-) compared with WT islets. Removal of excess cholesterol from LDLR(-/-) islets normalized glucose- and tolbutamide-induced insulin release. Glucose-stimulated Ca(2+) handling was also normalized in cholesterol-depleted LDLR(-/-) islets. Cholesterol removal from WT islets by 0.1 and 1.0mmol/l MβCD impaired both GSIS and Ca(2+) handling. In addition, at 10mmol/l MβCD WT islet showed a loss of membrane integrity and higher DNA fragmentation. Abnormally high (LDLR(-/-) islets) or low cholesterol content (WT islets treated with MβCD) alters both GSIS and Ca(2+) handling. Normalization of cholesterol improves Ca(2+) handling and insulin secretion in LDLR(-/-) islets. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Whole organ and islet of Langerhans dosimetry for calculation of absorbed doses resulting from imaging with radiolabeled exendin

    PubMed Central

    van der Kroon, Inge; Woliner-van der Weg, Wietske; Brom, Maarten; Joosten, Lieke; Frielink, Cathelijne; Konijnenberg, Mark W.; Visser, Eric P.; Gotthardt, Martin

    2017-01-01

    Radiolabeled exendin is used for non-invasive quantification of beta cells in the islets of Langerhans in vivo. High accumulation of radiolabeled exendin in the islets raised concerns about possible radiation-induced damage to these islets in man. In this work, islet absorbed doses resulting from exendin-imaging were calculated by combining whole organ dosimetry with small scale dosimetry for the islets. Our model contains the tissues with high accumulation of radiolabeled exendin: kidneys, pancreas and islets. As input for the model, data from a clinical study (radiolabeled exendin distribution in the human body) and from a preclinical study with Biobreeding Diabetes Prone (BBDP) rats (islet-to-exocrine uptake ratio, beta cell mass) were used. We simulated 111In-exendin and 68Ga-exendin absorbed doses in patients with differences in gender, islet size, beta cell mass and radiopharmaceutical uptake in the kidneys. In all simulated cases the islet absorbed dose was small, maximum 1.38 mGy for 68Ga and 66.0 mGy for 111In. The two sources mainly contributing to the islet absorbed dose are the kidneys (33–61%) and the islet self-dose (7.5–57%). In conclusion, all islet absorbed doses are low (<70 mGy), so even repeated imaging will hardly increase the risk on diabetes. PMID:28067253

  15. Changes induced by sucrose administration on glucose metabolism in pancreatic islets in normal hamsters.

    PubMed

    Massa, M L; Borelli, M I; Del Zotto, H; Gagliardino, J J

    2001-12-01

    We correlated the changes in glucose-induced insulin secretion with those observed in glucose metabolism and hexokinase/glucokinase activity in islets from normal sucrose-fed hamsters. Blood glucose and insulin levels were measured in normal male hamsters fed with (S5) or without (C5) 10% sucrose in the drinking water for 5 weeks. Isolated islets (collagenase digestion) from both groups of animals were used to study insulin secretion, (14)CO(2) and (3)H(2)O production from D-[U-(14)C]-glucose and D-[5-(3)H]-glucose respectively, with 3.3 or 16.7 mM glucose in the medium, and hexokinase/glucokinase activity (fluorometric assay) in islet homogenates. Whereas S5 and C5 animals had comparable normal blood glucose levels, S5 showed higher insulin levels than C5 hamsters (2.3+/-0.1 vs 0.6+/-0.03 ng/ml, P<0.001). Islets from S5 hamsters released significantly more insulin than C5 islets in the presence of low and high glucose (3.3 mM glucose: 0.77+/-0.04 vs 0.20+/-0.06 pg/ng DNA/min, P<0.001; 16.7 mM glucose: 2.77+/-0.12 vs 0.85+/-0.06 pg/ng DNA/min, P<0.001) and produced significantly higher amounts of (14)CO(2) and (3)H(2)O at both glucose concentrations ((14)CO(2): 3.3 mM glucose: 0.27+/-0.01 vs 0.18+/-0.01, P<0.001; 16.7 mM glucose: 1.44+/-0.15 vs 0.96+/-0.08, P<0.02; (3)H(2)O: 3.3 mM glucose: 0.31+/-0.02 vs 0.15+/-0.01, P<0.001; 16.7 mM glucose: 1.46+/-0.20 vs 0.76+/-0.05 pmol glucose/ng DNA/min, P<0.005). The hexokinase K(m) and V(max) values from S5 animals were significantly higher than those from C5 ones (K(m): 100.14+/-7.01 vs 59.90+/- 3.95 microM, P<0.001; V(max): 0.010+/-0.0005 vs 0.008+/- 0.0006 pmol glucose/ng DNA/min, P<0.02). Conversely, the glucokinase K(m) value from S5 animals was significantly lower than in C5 animals (K(m): 15.31+/-2.64 vs 35.01+/-1.65 mM, P<0.001), whereas V(max) figures were within a comparable range in both groups (V(max): 0.048+/-0.009 vs 0.094+/-0.035 pmol glucose/ng DNA/min, not significant). The glucose phosphorylation ratio

  16. Cooling dissociates glucose-induced insulin release from electrical activity and cation fluxes in rodent pancreatic islets.

    PubMed Central

    Atwater, I; Goncalves, A; Herchuelz, A; Lebrun, P; Malaisse, W J; Rojas, E; Scott, A

    1984-01-01

    Insulin release and beta-cell membrane potentials in response to glucose at 37 and 27 degrees C have been measured simultaneously in single, micro-dissected, perifused islets of Langerhans from normal mice. Insulin release and 45Ca outflow in response to glucose at 37 and 27 degrees C have been measured simultaneously from perfused islets isolated by collagenase digestion from normal rats. The effect of cooling on beta-cell membrane potassium permeability was assessed by changes in measured membrane potential and input resistance (in the mouse) and by changes in 86Rb outflow (in the rat). Resting and active beta-cell membrane parameters (i.e. membrane potential, spike frequency, input resistance, 45Ca outflow and 86Rb outflow), in both mouse and rat islets, were affected only slightly by cooling to 27 degrees C, with temperature coefficients of 2 or lower. At 27 degrees C glucose-stimulated insulin release was inhibited completely in mouse islets and almost completely in rat islets. The temperature coefficients in both preparations were greater than 5. It is concluded that beta-cell electrical activity and changes in membrane permeability induced by glucose are not consequences of insulin release. PMID:6371219

  17. Pancreatic-derived factor (FAM3B), a novel islet cytokine, induces apoptosis of insulin-secreting beta-cells.

    PubMed

    Cao, Xiaopei; Gao, Zhiyong; Robert, Claudia E; Greene, Scott; Xu, Gang; Xu, Weizhen; Bell, Ewan; Campbell, Don; Zhu, Yuan; Young, Robert; Trucco, Matteo; Markmann, James F; Naji, Ali; Wolf, Bryan A

    2003-09-01

    PANDER (PANcreatic DERived factor, FAM3B), a newly discovered secreted cytokine, is specifically expressed at high levels in the islets of Langerhans of the endocrine pancreas. To evaluate the role of PANDER in beta-cell function, we investigated the effects of PANDER on rat, mouse, and human pancreatic islets; the beta-TC3 cell line; and the alpha-TC cell line. PANDER protein was present in alpha- and beta-cells of pancreatic islets, insulin-secreting beta-TC3 cells, and glucagon-secreting alpha-TC cells. PANDER induced islet cell death in rat and human islets. Culture of beta-TC3 cells with recombinant PANDER had a dose-dependent inhibitory effect on cell viability. This effect was also time-dependent. PANDER caused apoptosis of beta-cells as assessed by electron microscopy, annexin V fluorescent staining, and flow-cytometric terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. PANDER did not affect cytosolic Ca(2+) levels or nitric oxide levels. However, PANDER activated caspase-3. Hence, PANDER may have a role in the process of pancreatic beta-cell apoptosis.

  18. Apoptosis induced by islet amyloid polypeptide soluble oligomers is neutralized by diabetes-associated specific antibodies

    PubMed Central

    Bram, Yaron; Frydman-Marom, Anat; Yanai, Inbal; Gilead, Sharon; Shaltiel-Karyo, Ronit; Amdursky, Nadav; Gazit, Ehud

    2014-01-01

    Soluble oligomeric assemblies of amyloidal proteins appear to act as major pathological agents in several degenerative disorders. Isolation and characterization of these oligomers is a pivotal step towards determination of their pathological relevance. Here we describe the isolation of Type 2 diabetes-associated islet amyloid polypeptide soluble cytotoxic oligomers; these oligomers induced apoptosis in cultured pancreatic cells, permeated model lipid vesicles and interacted with cell membranes following complete internalization. Moreover, antibodies which specifically recognized these assemblies, but not monomers or amyloid fibrils, were exclusively identified in diabetic patients and were shown to neutralize the apoptotic effect induced by these oligomers. Our findings support the notion that human IAPP peptide can form highly toxic oligomers. The presence of antibodies identified in the serum of diabetic patients confirms the pathological relevance of the oligomers. In addition, the newly identified structural epitopes may also provide new mechanistic insights and a molecular target for future therapy. PMID:24589570

  19. Apoptosis induced by islet amyloid polypeptide soluble oligomers is neutralized by diabetes-associated specific antibodies.

    PubMed

    Bram, Yaron; Frydman-Marom, Anat; Yanai, Inbal; Gilead, Sharon; Shaltiel-Karyo, Ronit; Amdursky, Nadav; Gazit, Ehud

    2014-03-04

    Soluble oligomeric assemblies of amyloidal proteins appear to act as major pathological agents in several degenerative disorders. Isolation and characterization of these oligomers is a pivotal step towards determination of their pathological relevance. Here we describe the isolation of Type 2 diabetes-associated islet amyloid polypeptide soluble cytotoxic oligomers; these oligomers induced apoptosis in cultured pancreatic cells, permeated model lipid vesicles and interacted with cell membranes following complete internalization. Moreover, antibodies which specifically recognized these assemblies, but not monomers or amyloid fibrils, were exclusively identified in diabetic patients and were shown to neutralize the apoptotic effect induced by these oligomers. Our findings support the notion that human IAPP peptide can form highly toxic oligomers. The presence of antibodies identified in the serum of diabetic patients confirms the pathological relevance of the oligomers. In addition, the newly identified structural epitopes may also provide new mechanistic insights and a molecular target for future therapy.

  20. Zinc sulphate induces metallothionein in pancreatic islets of mice and protects against diabetes induced by multiple low doses of streptozotocin.

    PubMed

    Ohly, P; Dohle, C; Abel, J; Seissler, J; Gleichmann, H

    2000-08-01

    Diabetes is induced by multiple low doses of streptozotocin (MLD-STZ) in male mice of susceptible strains. In this model beta-cell injury and T-cell-mediated inflammatory reactions are induced. Probably, reactive oxygen species (ROS) participate in the destruction of beta cells. The effects of ROS can be counterbalanced by several antioxidant systems. One of these is metallothionein (MT), cytosolic proteins that are induced by zinc ions (Zn2+) and scavenge hydroxyl radicals (OH). The effect of Zn2+ on MLD-STZ-diabetes was studied. We gave C57BL/6 and (C57BL/6 x SJL)F1 hybrid mice either MLD-STZ or in addition Zn2+-enriched drinking water. We analysed metallothionein ex vivo in pancreatic islets for protein and mRNA concentration for the isoforms 1 and 2. Pancreatic sections were examined by immunohistochemistry for metallothionein and histologically for insulitis. In both strains, Zn2+-enriched drinking water significantly up-regulated metallothionein and prevented MLD-STZ-diabetes and loss of beta-cell function. In the F1 hybrid mice a variant of MLD-STZ-diabetes was observed. These mice developed hyperglycaemia 10 weeks after the first injection of STZ (in contrast to 2 weeks observed in other mouse strains) and pronounced insulitis. The mRNA of the metallothionein isoforms 1 and 2 were constitutively expressed and slightly up-regulated by Zn2+-enriched drinking water. All islets cells stained for metallothionein. Drinking water enriched with Zn2+ significantly up-regulated metallothionein production in pancreatic islets of mice and prevented diabetes induced with MLD-STZ.

  1. Fibroblast populated collagen matrix promotes islet survival and reduces the number of islets required for diabetes reversal.

    PubMed

    Jalili, Reza B; Moeen Rezakhanlou, Alireza; Hosseini-Tabatabaei, Azadeh; Ao, Ziliang; Warnock, Garth L; Ghahary, Aziz

    2011-07-01

    Islet transplantation represents a viable treatment for type 1 diabetes. However, due to loss of substantial mass of islets early after transplantation, islets from two or more donors are required to achieve insulin independence. Islet-extracellular matrix disengagement, which occurs during islet isolation process, leads to subsequent islet cell apoptosis and is an important contributing factor to early islet loss. In this study, we developed a fibroblast populated collagen matrix (FPCM) as a novel scaffold to improve islet cell viability and function post-transplantation. FPCM was developed by embedding fibroblasts within type-I collagen and used as scaffold for islet grafts. Viability and insulin secretory function of islets embedded within FPCM was evaluated in vitro and in a syngeneic murine islet transplantation model. Islets embedded within acellular matrix or naked islets were used as control. Islet cell survival and function was markedly improved particularly after embedding within FPCM. The composite scaffold significantly promoted islet isograft survival and reduced the critical islet mass required for diabetes reversal by half (from 200 to 100 islets per recipient). Fibroblast embedded within FPCM produced fibronectin and growth factors and induced islet cell proliferation. No evidence of fibroblast over-growth within composite grafts was noticed. These results confirm that FPCM significantly promotes islet viability and functionality, enhances engraftment of islet grafts and decreases the critical islet mass needed to reverse hyperglycemia. This promising finding offers a new approach to reducing the number of islet donors per recipient and improving islet transplant outcome.

  2. α-1 Antitrypsin Enhances Islet Engraftment by Suppression of Instant Blood-Mediated Inflammatory Reaction.

    PubMed

    Wang, Jingjing; Sun, Zhen; Gou, Wenyu; Adams, David B; Cui, Wanxing; Morgan, Katherine A; Strange, Charlie; Wang, Hongjun

    2017-04-01

    Islet cell transplantation has limited effectiveness because of an instant blood-mediated inflammatory reaction (IBMIR) that occurs immediately after cell infusion and leads to dramatic β-cell death. In intraportal islet transplantation models using mouse and human islets, we demonstrated that α-1 antitrypsin (AAT; Prolastin-C), a serine protease inhibitor used for the treatment of AAT deficiency, inhibits IBMIR and cytokine-induced inflammation in islets. In mice, more diabetic recipients reached normoglycemia after intraportal islet transplantation when they were treated with AAT compared with mice treated with saline. AAT suppressed blood-mediated coagulation pathways by diminishing tissue factor production, reducing plasma thrombin-antithrombin complex levels and fibrinogen deposition on islet grafts, which correlated with less graft damage and apoptosis. AAT-treated mice showed reduced serum tumor necrosis factor-α levels, decreased lymphocytic infiltration, and decreased nuclear factor (NF)-κB activation compared with controls. The potent anti-inflammatory effect of AAT is possibly mediated by suppression of c-Jun N-terminal kinase (JNK) phosphorylation. Blocking JNK activation failed to further reduce cytokine-induced apoptosis in β-cells. Taken together, AAT significantly improves islet graft survival after intraportal islet transplantation by mitigation of coagulation in IBMIR and suppression of cytokine-induced JNK and NF-κB activation. AAT-based therapy has the potential to improve graft survival in human islet transplantation and other cellular therapies on the horizon.

  3. Hypoxia-inducible factor-1α regulates β cell function in mouse and human islets

    PubMed Central

    Cheng, Kim; Ho, Kenneth; Stokes, Rebecca; Scott, Christopher; Lau, Sue Mei; Hawthorne, Wayne J.; O’Connell, Philip J.; Loudovaris, Thomas; Kay, Thomas W.; Kulkarni, Rohit N.; Okada, Terumasa; Wang, Xiaohui L.; Yim, Sun Hee; Shah, Yatrik; Grey, Shane T.; Biankin, Andrew V.; Kench, James G.; Laybutt, D. Ross; Gonzalez, Frank J.; Kahn, C. Ronald; Gunton, Jenny E.

    2010-01-01

    Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that regulates cellular stress responses. While the levels of HIF-1α protein are tightly regulated, recent studies suggest that it can be active under normoxic conditions. We hypothesized that HIF-1α is required for normal β cell function and reserve and that dysregulation may contribute to the pathogenesis of type 2 diabetes (T2D). Here we show that HIF-1α protein is present at low levels in mouse and human normoxic β cells and islets. Decreased levels of HIF-1α impaired glucose-stimulated ATP generation and β cell function. C57BL/6 mice with β cell–specific Hif1a disruption (referred to herein as β-Hif1a-null mice) exhibited glucose intolerance, β cell dysfunction, and developed severe glucose intolerance on a high-fat diet. Increasing HIF-1α levels by inhibiting its degradation through iron chelation markedly improved insulin secretion and glucose tolerance in control mice fed a high-fat diet but not in β-Hif1a-null mice. Increasing HIF-1α levels markedly increased expression of ARNT and other genes in human T2D islets and improved their function. Further analysis indicated that HIF-1α was bound to the Arnt promoter in a mouse β cell line, suggesting direct regulation. Taken together, these findings suggest an important role for HIF-1α in β cell reserve and regulation of ARNT expression and demonstrate that HIF-1α is a potential therapeutic target for the β cell dysfunction of T2D. PMID:20440072

  4. [Impairment of pancreatic islet beta cell function induced by intermittent high glucose through oxidative and endoplasmic reticulum stress: experiment with rat pancreatic islet beta cells].

    PubMed

    Hou, Zhi-qiang; Li, Hong-liang; Zhao, Jia-jun; Li, Guang-wei

    2008-07-22

    To investigate the effect of intermittent high glucose (IHG) on the pancreatic islet beta-cell function and mechanism thereof. Rat pancreatic islet p-cells of the line INS-1 were cultured and randomly divided into 3 groups: IHG group exposed to fluctuating concentrations of glucose, stable high glucose (SHG) group exposed to 16. 7 mmol/L glucose, and control group exposed to normal concentration (5.5 mmol/L) glucose. 24, 48, and 72 hours later radioimmunoassay was used to detect the insulin secretion index (ISI). 72 h later, the concentration of insulin in the cells was detected with radioimmunoassay. The contents of oxidative stress markers, nitrotyrosine (NT) and 8-hydroxy-2-deoxyguanosine (8-OHdG) were detected. Real-time PCR was used to detect the mRNA expression of peroxiredoxin 1 (PDX-1), ATF-4, one of the transcription factors of the family bZIP, and insulin. Western blotting was used to detect the protein expression of ATF-4. The ISI of the IHG and SHG groups decreased time-dependently, The ISI of IHG and SHG groups were 0.64 +/- 0.11 and 1.31 +/- 0. 04 respectively, both significantly lower than that of the control group (1.67 +/- 0.23, both P < 0.05). The intracellular insulin contents of the IHG and SHG groups were (10.91 +/- 0.14) and (11.08 +/- 0.03) +/- U/microg respectively, both significantly lower than that of the control group [(12.37 +/- 0.37) microU/microg, both P < 0.05]. The intracellular concentrations of 8-OHdG and NT of the SHG and IHG groups, were significantly higher than those of the control group (all P < 0.01), and those of the IHG group were significantly higher than those of the SHG group (both P < 0.05). The mRNA and protein expression levels of ATF-4 of the IHG group were all significantly higher than those of the control group (all P < 0.05) and those of the IHG group were significantly higher than those of the SHG group (both P < 0.05). IHG and SHG induce severe impairment in pancreatic islet beta cell functions, especially IHG

  5. Successful β cells islet regeneration in streptozotocin-induced diabetic baboons using ultrasound-targeted microbubble gene therapy with cyclinD2/CDK4/GLP1.

    PubMed

    Chen, Shuyuan; Bastarrachea, Raul A; Roberts, Brad J; Voruganti, V Saroja; Frost, Patrice A; Nava-Gonzalez, Edna J; Arriaga-Cazares, Hector E; Chen, Jiaxi; Huang, Pintong; DeFronzo, Ralph A; Comuzzie, Anthony G; Grayburn, Paul A

    2014-01-01

    Both major forms of diabetes mellitus (DM) involve β-cell destruction and dysfunction. New treatment strategies have focused on replenishing the deficiency of β-cell mass common to both major forms of diabetes by islet transplantation or β-cell regeneration. The pancreas, not the liver, is the ideal organ for islet regeneration, because it is the natural milieu for islets. Since islet mass is known to increase during obesity and pregnancy, the concept of stimulating pancreatic islet regeneration in vivo is both rational and physiologic. This paper proposes a novel approach in which non-viral gene therapy is targeted to pancreatic islets using ultrasound targeted microbubble destruction (UTMD) in a non-human primate model (NHP), the baboon. Treated baboons received a gene cocktail comprised of cyclinD2, CDK, and GLP1, which in rats results in robust and durable islet regeneration with normalization of blood glucose, insulin, and C-peptide levels. We were able to generate important preliminary data indicating that gene therapy by UTMD can achieve in vivo normalization of the intravenous (IV) glucose tolerance test (IVGTT) curves in STZ hyperglycemic-induced conscious tethered baboons. Immunohistochemistry clearly demonstrated evidence of islet regeneration and restoration of β-cell mass.

  6. Long-term in vivo polychlorinated biphenyl 126 exposure induces oxidative stress and alters proteomic profile on islets of Langerhans

    NASA Astrophysics Data System (ADS)

    Loiola, Rodrigo Azevedo; Dos Anjos, Fabyana Maria; Shimada, Ana Lúcia; Cruz, Wesley Soares; Drewes, Carine Cristiane; Rodrigues, Stephen Fernandes; Cardozo, Karina Helena Morais; Carvalho, Valdemir Melechco; Pinto, Ernani; Farsky, Sandra Helena

    2016-06-01

    It has been recently proposed that exposure to polychlorinated biphenyls (PCBs) is a risk factor to type 2 diabetes mellitus (DM2). We investigated this hypothesis using long-term in vivo PCB126 exposure to rats addressing metabolic, cellular and proteomic parameters. Male Wistar rats were exposed to PCB126 (0.1, 1 or 10 μg/kg of body weight/day; for 15 days) or vehicle by intranasal instillation. Systemic alterations were quantified by body weight, insulin and glucose tolerance, and blood biochemical profile. Pancreatic toxicity was measured by inflammatory parameters, cell viability and cycle, free radical generation, and proteomic profile on islets of Langerhans. In vivo PCB126 exposure enhanced the body weight gain, impaired insulin sensitivity, reduced adipose tissue deposit, and elevated serum triglycerides, cholesterol, and insulin levels. Inflammatory parameters in the pancreas and cell morphology, viability and cycle were not altered in islets of Langerhans. Nevertheless, in vivo PCB126 exposure increased free radical generation and modified the expression of proteins related to oxidative stress on islets of Langerhans, which are indicative of early β-cell failure. Data herein obtained show that long-term in vivo PCB126 exposure through intranasal route induced alterations on islets of Langerhans related to early end points of DM2.

  7. Long-term in vivo polychlorinated biphenyl 126 exposure induces oxidative stress and alters proteomic profile on islets of Langerhans

    PubMed Central

    Loiola, Rodrigo Azevedo; dos Anjos, Fabyana Maria; Shimada, Ana Lúcia; Cruz, Wesley Soares; Drewes, Carine Cristiane; Rodrigues, Stephen Fernandes; Cardozo, Karina Helena Morais; Carvalho, Valdemir Melechco; Pinto, Ernani; Farsky, Sandra Helena

    2016-01-01

    It has been recently proposed that exposure to polychlorinated biphenyls (PCBs) is a risk factor to type 2 diabetes mellitus (DM2). We investigated this hypothesis using long-term in vivo PCB126 exposure to rats addressing metabolic, cellular and proteomic parameters. Male Wistar rats were exposed to PCB126 (0.1, 1 or 10 μg/kg of body weight/day; for 15 days) or vehicle by intranasal instillation. Systemic alterations were quantified by body weight, insulin and glucose tolerance, and blood biochemical profile. Pancreatic toxicity was measured by inflammatory parameters, cell viability and cycle, free radical generation, and proteomic profile on islets of Langerhans. In vivo PCB126 exposure enhanced the body weight gain, impaired insulin sensitivity, reduced adipose tissue deposit, and elevated serum triglycerides, cholesterol, and insulin levels. Inflammatory parameters in the pancreas and cell morphology, viability and cycle were not altered in islets of Langerhans. Nevertheless, in vivo PCB126 exposure increased free radical generation and modified the expression of proteins related to oxidative stress on islets of Langerhans, which are indicative of early β-cell failure. Data herein obtained show that long-term in vivo PCB126 exposure through intranasal route induced alterations on islets of Langerhans related to early end points of DM2. PMID:27292372

  8. Baccharis dracunculifolia methanol extract enhances glucose-stimulated insulin secretion in pancreatic islets of monosodium glutamate induced-obesity model rats.

    PubMed

    Hocayen, Palloma de A S; Grassiolli, Sabrina; Leite, Nayara C; Pochapski, Márcia T; Pereira, Ricardo A; da Silva, Luiz A; Snack, Andre L; Michel, R Garcia; Kagimura, Francini Y; da Cunha, Mário A A; Malfatti, Carlos R M

    2016-07-01

    Obesity is the main risk factor for type 2 diabetes mellitus. Secondary metabolites with biological activities and pharmacological potential have been identified in species of the Baccharis genus that are specifically distributed in the Americas. This study evaluated the effects of methanol extracts from Baccharis dracunculifolia DC. Asteraceae on metabolic parameters, satiety, and growth in monosodium glutamate (MSG) induced-obesity model rats. MSG was administered to 32 newborn rats (4 mg/g of body weight) once daily for 5 consecutive days. Four experimental groups (control, control + extract, MSG, and MSG + extract) were treated for 30 consecutive days with 400 mg/kg of B. dracunculifolia extract by gavage. Biochemical parameters, antioxidant activity, total extract phenolic content (methanolic, ethanolic, and acetone extractions), and pancreatic islets were evaluated. High levels of phenolic compounds were identified in B. dracunculifolia extracts (methanol: 46.2 ± 0.4 mg GAE/L; acetate: 70.5 ± 0.5 mg GAE/L; and ethanol: 30.3 ± 0.21 mg GAE/L); high antioxidant activity was detected in B. dracunculifolia ethanol and methanol extracts. The concentration of serum insulin increased 30% in obese animals treated with extract solutions (1.4-2.0 µU/mL, p < 0.05). Insulin secretion in pancreatic islets was 8.3 mM glucose (58%, p < 0.05) and 16.7 mM (99.5%, p < 0.05) in rats in the MSG + extract and MSG groups, respectively. Treatment with B. dracunculifolia extracts protected pancreatic islets and prevented the irreversible cellular damage observed in animals in obesity and diabetes models.

  9. Evaluation of low doses BPA-induced perturbation of glycemia by toxicogenomics points to a primary role of pancreatic islets and to the mechanism of toxicity.

    PubMed

    Carchia, E; Porreca, I; Almeida, P J; D'Angelo, F; Cuomo, D; Ceccarelli, M; De Felice, M; Mallardo, M; Ambrosino, C

    2015-10-29

    Epidemiologic and experimental studies have associated changes of blood glucose homeostasis to Bisphenol A (BPA) exposure. We took a toxicogenomic approach to investigate the mechanisms of low-dose (1 × 10(-9 )M) BPA toxicity in ex vivo cultures of primary murine pancreatic islets and hepatocytes. Twenty-nine inhibited genes were identified in islets and none in exposed hepatocytes. Although their expression was slightly altered, their impaired cellular level, as a whole, resulted in specific phenotypic changes. Damage of mitochondrial function and metabolism, as predicted by bioinformatics analyses, was observed: BPA exposure led to a time-dependent decrease in mitochondrial membrane potential, to an increase of ROS cellular levels and, finally, to an induction of apoptosis, attributable to the bigger Bax/Bcl-2 ratio owing to activation of NF-κB pathway. Our data suggest a multifactorial mechanism for BPA toxicity in pancreatic islets with emphasis to mitochondria dysfunction and NF-κB activation. Finally, we assessed in vitro the viability of BPA-treated islets in stressing condition, as exposure to high glucose, evidencing a reduced ability of the exposed islets to respond to further damages. The result was confirmed in vivo evaluating the reduction of glycemia in hyperglycemic mice transplanted with control and BPA-treated pancreatic islets. The reported findings identify the pancreatic islet as the main target of BPA toxicity in impairing the glycemia. They suggest that the BPA exposure can weaken the response of the pancreatic islets to damages. The last observation could represent a broader concept whose consideration should lead to the development of experimental plans better reproducing the multiple exposure conditions.

  10. Curcumin enhances recovery of pancreatic islets from cellular stress induced inflammation and apoptosis in diabetic rats

    SciTech Connect

    Rashid, Kahkashan; Sil, Parames C.

    2015-02-01

    The phytochemical, curcumin, has been reported to play many beneficial roles. However, under diabetic conditions, the detail mechanism of its beneficial action in the glucose homeostasis regulatory organ, pancreas, is poorly understood. The present study has been designed and carried out to explore the role of curcumin in the pancreatic tissue of STZ induced and cellular stress mediated diabetes in eight weeks old male Wistar rats. Diabetes was induced with a single intraperitoneal dose of STZ (65 mg/kg body weight). Post to diabetes induction, animals were treated with curcumin at a dose of 100 mg/kg body weight for eight weeks. Underlying molecular and cellular mechanism was determined using various biochemical assays, DNA fragmentation, FACS, histology, immunoblotting and ELISA. Treatment with curcumin reduced blood glucose level, increased plasma insulin and mitigated oxidative stress related markers. In vivo and in vitro experimental results revealed increased levels of proinflammatory cytokines (TNF-α, IL1-β and IFN-γ), reduced level of cellular defense proteins (Nrf-2 and HO-1) and glucose transporter (GLUT-2) along with enhanced levels of signaling molecules of ER stress dependent and independent apoptosis (cleaved Caspase-12/9/8/3) in STZ administered group. Treatment with curcumin ameliorated all the adverse changes and helps the organ back to its normal physiology. Results suggest that curcumin protects pancreatic beta-cells by attenuating inflammatory responses, and inhibiting ER/mitochondrial dependent and independent pathways of apoptosis and crosstalk between them. This uniqueness and absence of any detectable adverse effect proposes the possibility of using this molecule as an effective protector in the cellular stress mediated diabetes mellitus. - Highlights: • STZ induced cellular stress plays a vital role in pancreatic dysfunction. • Cellular stress causes inflammation, pancreatic islet cell death and diabetes. • Deregulation of Nrf-2

  11. Distinct Cell Clusters Touching Islet Cells Induce Islet Cell Replication in Association with Over-Expression of Regenerating Gene (REG) Protein in Fulminant Type 1 Diabetes

    PubMed Central

    Aida, Kaoru; Saitoh, Sei; Nishida, Yoriko; Yokota, Sadanori; Ohno, Shinichi; Mao, Xiayang; Akiyama, Daiichiro; Tanaka, Shoichiro; Awata, Takuya; Shimada, Akira; Oikawa, Youichi; Shimura, Hiroki; Furuya, Fumihiko; Takizawa, Soichi; Ichijo, Masashi; Ichijo, Sayaka; Itakura, Jun; Fujii, Hideki; Hashiguchi, Akinori; Takasawa, Shin; Endo, Toyoshi; Kobayashi, Tetsuro

    2014-01-01

    Background Pancreatic islet endocrine cell-supporting architectures, including islet encapsulating basement membranes (BMs), extracellular matrix (ECM), and possible cell clusters, are unclear. Procedures The architectures around islet cell clusters, including BMs, ECM, and pancreatic acinar-like cell clusters, were studied in the non-diabetic state and in the inflamed milieu of fulminant type 1 diabetes in humans. Result Immunohistochemical and electron microscopy analyses demonstrated that human islet cell clusters and acinar-like cell clusters adhere directly to each other with desmosomal structures and coated-pit-like structures between the two cell clusters. The two cell-clusters are encapsulated by a continuous capsule composed of common BMs/ECM. The acinar-like cell clusters have vesicles containing regenerating (REG) Iα protein. The vesicles containing REG Iα protein are directly secreted to islet cells. In the inflamed milieu of fulminant type 1 diabetes, the acinar-like cell clusters over-expressed REG Iα protein. Islet endocrine cells, including beta-cells and non-beta cells, which were packed with the acinar-like cell clusters, show self-replication with a markedly increased number of Ki67-positive cells. Conclusion The acinar-like cell clusters touching islet endocrine cells are distinct, because the cell clusters are packed with pancreatic islet clusters and surrounded by common BMs/ECM. Furthermore, the acinar-like cell clusters express REG Iα protein and secrete directly to neighboring islet endocrine cells in the non-diabetic state, and the cell clusters over-express REG Iα in the inflamed milieu of fulminant type 1 diabetes with marked self-replication of islet cells. PMID:24759849

  12. Pancreatic Islet Transplantation

    MedlinePlus

    ... islets, also called islets of Langerhans, are tiny clusters of cells scattered throughout the pancreas. The pancreas ... islets, also called islets of Langerhans, are tiny clusters of cells scattered throughout the pancreas. Pancreatic islets ...

  13. Membrane Curvature-sensing and Curvature-inducing Activity of Islet Amyloid Polypeptide and Its Implications for Membrane Disruption*♦

    PubMed Central

    Kegulian, Natalie C.; Sankhagowit, Shalene; Apostolidou, Melania; Jayasinghe, Sajith A.; Malmstadt, Noah; Butler, Peter C.; Langen, Ralf

    2015-01-01

    Islet amyloid polypeptide (IAPP) is a 37-amino acid amyloid protein intimately associated with pancreatic islet β-cell dysfunction and death in type II diabetes. In this study, we combine spectroscopic methods and microscopy to investigate α-helical IAPP-membrane interactions. Using light scattering and fluorescence microscopy, we observe that larger vesicles become smaller upon treatment with human or rat IAPP. Electron microscopy shows the formation of various highly curved structures such as tubules or smaller vesicles in a membrane-remodeling process, and spectrofluorometric detection of vesicle leakage shows disruption of membrane integrity. This effect is stronger for human IAPP than for the less toxic rat IAPP. From CD spectra in the presence of different-sized vesicles, we also uncover the membrane curvature-sensing ability of IAPP and find that it transitions from inducing to sensing membrane curvature when lipid negative charge is decreased. Our in vivo EM images of immunogold-labeled rat IAPP and human IAPP show both forms to localize to mitochondrial cristae, which contain not only locally curved membranes but also phosphatidylethanolamine and cardiolipin, lipids with high spontaneous negative curvature. Disruption of membrane integrity by induction of membrane curvature could apply more broadly to other amyloid proteins and be responsible for membrane damage observed in other amyloid diseases as well. PMID:26283787

  14. Glucose-induced β cell production of IL-1β contributes to glucotoxicity in human pancreatic islets

    PubMed Central

    Maedler, Kathrin; Sergeev, Pavel; Ris, Frédéric; Oberholzer, José; Joller-Jemelka, Helen I.; Spinas, Giatgen A.; Kaiser, Nurit; Halban, Philippe A.; Donath, Marc Y.

    2002-01-01

    In type 2 diabetes, chronic hyperglycemia is suggested to be detrimental to pancreatic β cells, causing impaired insulin secretion. IL-1β is a proinflammatory cytokine acting during the autoimmune process of type 1 diabetes. IL-1β inhibits β cell function and promotes Fas-triggered apoptosis in part by activating the transcription factor NF-κB. Recently, we have shown that increased glucose concentrations also induce Fas expression and β cell apoptosis in human islets. The aim of the present study was to test the hypothesis that IL-1β may mediate the deleterious effects of high glucose on human β cells. In vitro exposure of islets from nondiabetic organ donors to high glucose levels resulted in increased production and release of IL-1β, followed by NF-κB activation, Fas upregulation, DNA fragmentation, and impaired β cell function. The IL-1 receptor antagonist protected cultured human islets from these deleterious effects. β cells themselves were identified as the islet cellular source of glucose-induced IL-1β. In vivo, IL-1β–producing β cells were observed in pancreatic sections of type 2 diabetic patients but not in nondiabetic control subjects. Similarly, IL-1β was induced in β cells of the gerbil Psammomys obesus during development of diabetes. Treatment of the animals with phlorizin normalized plasma glucose and prevented β cell expression of IL-1β. These findings implicate an inflammatory process in the pathogenesis of glucotoxicity in type 2 diabetes and identify the IL-1β/NF-κB pathway as a target to preserve β cell mass and function in this condition. PMID:12235117

  15. Pancreatic islet plasticity: Interspecies comparison of islet architecture and composition

    PubMed Central

    Steiner, Donald J.; Kim, Abraham; Miller, Kevin; Hara, Manami

    2010-01-01

    The pancreatic islet displays diverse patterns of endocrine cell arrangement. The prototypic islet, with insulin-secreting β-cells forming the core surrounded by other endocrine cells in the periphery, is largely based on studies of normal rodent islets. Recent reports on large animals, including humans, show a difference in islet architecture, in which the endocrine cells are randomly distributed throughout the islet. This particular species difference has raised concerns regarding the interpretation of data based on rodent studies to humans. On the other hand, further variations have been reported in marsupials and some nonhuman primates, which possess an inverted ratio of β-cells to other endocrine cells. This review discusses the striking plasticity of islet architecture and cellular composition among various species including changes in response to metabolic states within a single species. We propose that this plasticity reflects evolutionary acquired adaptation induced by altered physiological conditions, rather than inherent disparities between species. PMID:20657742

  16. Diazoxide, a K(ATP) channel opener, prevents ischemia-reperfusion injury in rodent pancreatic islets.

    PubMed

    Wang, Yong; Wang, Shusen; Harvat, Tricia; Kinzer, Katie; Zhang, Lisa; Feng, Feng; Qi, Meirigeng; Oberholzer, Jose

    2015-01-01

    Diazoxide (DZ) is a pharmacological opener of ATP-sensitive K(+) channels that has been used for mimicking ischemic preconditioning and shows protection against ischemic damage. Here we investigated whether diazoxide supplementation to University of Wisconsin (UW) solution has cellular protection during islet isolation and improves in vivo islet transplant outcomes in a rodent ischemia model. C57/B6 mice pancreata were flushed with UW or UW + DZ solution and cold preserved for 6 or 10 h prior to islet isolation. Islet yield, in vitro and in vivo function, mitochondrial morphology, and apoptosis were evaluated. Significantly higher islet yields were observed in the UW + DZ group than in the UW group (237.5 ± 25.6 vs. 108.7 ± 49.3, p < 0.01). The islets from the UW + DZ group displayed a significantly higher glucose-induced insulin secretion (0.97 ng/ml ± 0.15 vs. 0.758 ng/ml ± 0.21, p = 0.009) and insulin content (60.96 ng/islet ± 13.94 vs. 42.09 ng/islet ± 8.15, p = 0.002). The DZ-treated islets had well-preserved mitochondrial morphology with superior responses of mitochondrial potentials, and calcium influx responded to glucose. A higher number of living cells and less late apoptotic cells were observed in the UW + DZ group (p < 0.05). Additionally, the islets from the UW + DZ group had a significantly higher cure rate and improved glucose tolerance. This study is the first to report mitoprotective effects of DZ for pancreas preservation and islet isolation. In the future, it will be necessary to further understand the underlying mechanism for the mitoprotection and to test this promising approach for pancreas preservation and the islet isolation process in nonhuman primates and ultimately humans.

  17. Diazoxide, a KATP Channel Opener, Prevents Ischemia-Reperfusion Injury in Rodent Pancreatic Islets

    PubMed Central

    Wang, Yong; Wang, Shusen; Harvat, Tricia; Kinzer, Katie; Zhang, Lisa; Feng, Feng; Qi, Meirigeng; Oberholzer, Jose

    2014-01-01

    Objective Diazoxide (DZ) is a pharmacological opener of ATP-sensitive K+ channels and has been used for mimicking ischemic preconditioning and shows protection against ischemic damage. Here, we investigated whether Diazoxide supplementation to University of Wisconsin (UW) solution has cellular protection during islet isolation and improves in vivo islet transplant outcomes in rodent ischemia model. Research Design and Methods C57/B6 mice pancreata were flushed with UW or UW+DZ solution and cold preserved for 6 or 10 hrs prior to islet isolation. Islet yield, in vitro and in vivo function, mitochondrial morphology, and apoptosis were evaluated. Results Significantly higher islet yields were observed in the UW+DZ group than in the UW group (237.5 ± 25.6 vs. 108.7 ± 49.3, p < 0.01). The islets from the UW+DZ group displayed a significantly higher glucose-induced insulin secretion (0.97 ng/ml ± 0.15 vs. 0.758 ng/ml ± 0.21, p = 0.009) and insulin content (6095.6 ng/islet ± 1394.5 vs. 4209.2 ng/islet ± 815.1, p = 0.002). The DZ-treated islets had well-preserved mitochondrial morphology with superior responses of mitochondrial potentials and calcium influx responded to glucose. Higher living cells and less late apoptotic cells were observed in the UW+DZ group (p < 0.05). Additionally, the transplanted islets from the UW+DZ group had a significantly higher cure rate and improved glucose tolerance. Conclusion This study is the first to report mitoprotective effects of DZ for pancreas preservation and islet isolation. It remains to be tested whether these findings can be replicated in human islet isolation and transplantation. PMID:24070013

  18. Transplantation models to characterize the mechanisms of stem cell-induced islet regeneration.

    PubMed

    Bell, Gillian I; Seneviratne, Ayesh K; Nasri, Grace N; Hess, David A

    2013-09-20

    This unit describes our current knowledge regarding the isolation human bone marrow-derived progenitor cells for the paracrine stimulation of islet regeneration after transplantation into immunodeficient mouse models of diabetes. By using high aldehyde dehydrogenase (ALDH(hi) ) activity, a conserved function in multiple stem cell lineages, a mixed population of hematopoietic, endothelial, and mesenchymal progenitor cells can be efficiently purified using flow cytometry. We describe in vitro approaches to characterize and expand these distinct cell types. Importantly, these cell types can be transplanted into immunodeficient mice rendered beta-cell deficient by streptozotocin (STZ) treatment, in order monitor functional recovery from hyperglycemia and to characterize endogenous islet regeneration via paracrine mechanisms. Herein, we provide detailed protocols for: (1) isolation and characterization of ALDH(hi) cells for the establishment of hematopoietic and multipotent-stromal progenitor lineages; (2) intravenous and intrapancreatic transplantation of human stem cell subtypes for the quantification of glycemic recovery in STZ-treated immunodeficient mice; and (3) immunohistochemical characterization of islet recovery via the stimulation of islet neogenic, beta-cell proliferative, and islet revascularization programs. Collectively, these systems can be used to support the pre-clinical development of human progenitor cell-based therapies to treat diabetes via islet regeneration.

  19. Effect of polishing induced subsurface damages on laser induced damage in fused silica optics

    NASA Astrophysics Data System (ADS)

    He, Xiang; Zhao, Heng; Huang, Ying; Cai, Chao; Hu, JiangChuan; Ma, Ping

    2016-10-01

    Conventional used ceria polishing would induce both of Ce contaminants and subsurface damages, which mainly restricts the laser induced damage resistance of fused silica optics. To control the near surface defects, nanometer sized colloidal silica are used to polish fused silica optics after the normal ceria polishing process. Then the contaminant elements and subsurface damages of the polished samples were analyzed by secondary ion mass spectrometry and Nomarski microscopy. It reveals that ceria polishing would introduce lots of subsurface damages whereas colloidal silica polishing induces much fewer subsurface damages especially no fracture induced severe subsurface damages. The laser damage tests reveal that subsequent colloidal silica polishing of the ceria pre-polished samples could gradually eliminate the ceria polishing induced subsurface damages and lower the laser induced damage density accordingly with the increased polishing time. But unlike the damage density, only the severe subsurface damages are totally eliminated could the damage threshold be substantially improved. These results incline to indicate that the subsurface damages have great influence on the laser induced damage density and the fracture related severe subsurface damages will greatly restrict the damage threshold in polished optics.

  20. Pancreatic β-Cell Membrane Fluidity and Toxicity Induced by Human Islet Amyloid Polypeptide Species

    PubMed Central

    Pilkington, Emily H.; Gurzov, Esteban N.; Kakinen, Aleksandr; Litwak, Sara A.; Stanley, William J.; Davis, Thomas P.; Ke, Pu Chun

    2016-01-01

    Aggregation of human islet amyloid polypeptide (hIAPP) into fibrils and plaques is associated with pancreatic β-cell loss in type 2 diabetes (T2D). However, due to the rapidness of hIAPP conversion in aqueous phase, exactly which hIAPP species is responsible for the observed toxicity and through what mechanisms remains ambiguous. In light of the importance of understanding hIAPP toxicity for T2D here we show a biophysical scheme based on the use of a lipophilic Laurdan dye for examining MIN6 cell membranes upon exposure to fresh and oligomeric hIAPP as well as mature amyloid. It has been found that all three hIAPP species, especially fresh hIAPP, enhanced membrane fluidity and caused losses in cell viability. The cell generation of reactive oxygen species (ROS), however, was the most pronounced with mature amyloid hIAPP. The correlation between changes in membrane fluidity and cell viability and their lack of correlation with ROS production suggest hIAPP toxicity is elicited through both physical and biochemical means. This study offers a new insight into β-cell toxicity induced by controlled hIAPP species, as well as new biophysical methodologies that may prove beneficial for the studies of T2D as well as neurological disorders. PMID:26880502

  1. Pancreatic β-Cell Membrane Fluidity and Toxicity Induced by Human Islet Amyloid Polypeptide Species

    NASA Astrophysics Data System (ADS)

    Pilkington, Emily H.; Gurzov, Esteban N.; Kakinen, Aleksandr; Litwak, Sara A.; Stanley, William J.; Davis, Thomas P.; Ke, Pu Chun

    2016-02-01

    Aggregation of human islet amyloid polypeptide (hIAPP) into fibrils and plaques is associated with pancreatic β-cell loss in type 2 diabetes (T2D). However, due to the rapidness of hIAPP conversion in aqueous phase, exactly which hIAPP species is responsible for the observed toxicity and through what mechanisms remains ambiguous. In light of the importance of understanding hIAPP toxicity for T2D here we show a biophysical scheme based on the use of a lipophilic Laurdan dye for examining MIN6 cell membranes upon exposure to fresh and oligomeric hIAPP as well as mature amyloid. It has been found that all three hIAPP species, especially fresh hIAPP, enhanced membrane fluidity and caused losses in cell viability. The cell generation of reactive oxygen species (ROS), however, was the most pronounced with mature amyloid hIAPP. The correlation between changes in membrane fluidity and cell viability and their lack of correlation with ROS production suggest hIAPP toxicity is elicited through both physical and biochemical means. This study offers a new insight into β-cell toxicity induced by controlled hIAPP species, as well as new biophysical methodologies that may prove beneficial for the studies of T2D as well as neurological disorders.

  2. Impact of islet size on pancreatic islet transplantation and potential interventions to improve outcome.

    PubMed

    Zorzi, Daria; Phan, Tammy; Sequi, Marco; Lin, Yong; Freeman, Daniel H; Cicalese, Luca; Rastellini, Cristiana

    2015-01-01

    Better results have been recently reported in clinical pancreatic islet transplantation (ITX) due mostly to improved isolation techniques and immunosuppression; however, some limitations still exist. It is known that following transplantation, 30% to 60% of the islets are lost. In our study, we have investigated 1) the role of size as a factor affecting islet engraftment and 2) potential procedural manipulations to increase the number of smaller functional islets that can be transplanted. C57/BL10 mice were used as donors and recipients in a syngeneic islet transplant model. Isolated islets were divided by size (large, >300 μm; medium 150-300 μm; small, <150 μm). Each size was transplanted in chemically induced diabetic mice as full (600 IEQ), suboptimal (400 IEQ), and marginal mass (200 IEQ). Control animals received all size islets. Engraftment was defined as reversal of diabetes by day 7 posttransplantation. When the superiority of smaller islets was observed, strategies of overdigestion and fragmentation were adopted during islet isolation in the attempt to reduce islet size and improve engraftment. Smaller islets were significantly superior in engraftment compared to medium, large, and control (all sizes) groups. This was more evident when marginal mass data were compared. In all masses, success decreased as islet size increased. Once islets were engrafted, functionality was not affected by size. When larger islets were fragmented, a significant decrease in islet functionality was observed. On the contrary, if pancreata were slightly overdigested, although not as successful as small naive islets, an increase in engraftment was observed when compared to the control group. In conclusion, smaller islets are superior in engraftment following islet transplantation. Fragmentation has a deleterious effect on islet engraftment. Islet isolations can be performed by reducing islet size with slight overdigestion, and it can be safely adopted to improve clinical

  3. PD-L1-driven tolerance protects neurogenin3-induced islet neogenesis to reverse established type 1 diabetes in NOD mice.

    PubMed

    Li, Rongying; Lee, Jeongkyung; Kim, Mi-sun; Liu, Victoria; Moulik, Mousumi; Li, Haiyan; Yi, Qing; Xie, Aini; Chen, Wenhao; Yang, Lina; Li, Yimin; Tsai, Tsung Huang; Oka, Kazuhiro; Chan, Lawrence; Yechoor, Vijay

    2015-02-01

    A breakdown in self-tolerance underlies autoimmune destruction of β-cells and type 1 diabetes. A cure by restoring β-cell mass is limited by the availability of transplantable β-cells and the need for chronic immunosuppression. Evidence indicates that inhibiting costimulation through the PD-1/PD-L1 pathway is central to immune tolerance. We therefore tested whether induction of islet neogenesis in the liver, protected by PD-L1-driven tolerance, reverses diabetes in NOD mice. We demonstrated a robust induction of neo-islets in the liver of diabetic NOD mice by gene transfer of Neurogenin3, the islet-defining factor, along with betacellulin, an islet growth factor. These neo-islets expressed all the major pancreatic hormones and transcription factors. However, an enduring restoration of glucose-stimulated insulin secretion and euglycemia occurs only when tolerance is also induced by the targeted overexpression of PD-L1 in the neo-islets, which results in inhibition of proliferation and increased apoptosis of infiltrating CD4(+) T cells. Further analysis revealed an inhibition of cytokine production from lymphocytes isolated from the liver but not from the spleen of treated mice, indicating that treatment did not result in generalized immunosuppression. This treatment strategy leads to persistence of functional neo-islets that resist autoimmune destruction and consequently an enduring reversal of diabetes in NOD mice.

  4. [Structural alterations in pancreatic islets in streptozotocin-induced diabetic rats treated with of bioactive additive on the basis of Gymnema sylvestre].

    PubMed

    Snigur, G L; Samokhina, M P; Pisarev, V B; Spasov, A A; Bulanov, A E

    2008-01-01

    The structural alterations in pancreatic islets in streptozotocin-induced diabetic rats were studied after the administration of Gymnema sylvestre extract or its composition. Diabetes mellitus was modeled by daily injection of streptozotocin (20 mg/kg for 5 days) and single injection of 0.2 ml of complete Freund's adjuvant, Only the animals with the blood glucose level exceeding 15 mmol/l were included in the experiment. B- and A-endocrinocytes were demonstrated using immunocytochemistry. The proportions of the area of the pancreatic islets, occupied by B- and A-endocrinocytes, as well as the volume fraction of the pancreatic islets within the pancreas, were determined. In the model of streptozotocin-induced diabetes, the part of the total islet area occupied by B-endocrinocytes, was diminished in the pancreatic islets located in all the zones of the gland. Prophylactic administration of Gymnema sylvestre extract or its composition tended to restore the area occupied by B-endocrinocytes in the pancreatic islets. These results indicate the equal potency of the composition and extract of Gymnema sylvestre to induce the regeneration of B-endocrinocytes.

  5. The Islet Estrogen Receptor-α Is Induced by Hyperglycemia and Protects Against Oxidative Stress-Induced Insulin-Deficient Diabetes

    PubMed Central

    Kilic, Gamze; Alvarez-Mercado, Ana I.; Zarrouki, Bader; Opland, Darren; Liew, Chong Wee; Alonso, Laura C.; Myers, Martin G.; Jonas, Jean-Christophe; Poitout, Vincent; Kulkarni, Rohit N.; Mauvais-Jarvis, Franck

    2014-01-01

    The female steroid, 17β-estradiol (E2), is important for pancreatic β-cell function and acts via at least three estrogen receptors (ER), ERα, ERβ, and the G-protein coupled ER (GPER). Using a pancreas-specific ERα knockout mouse generated using the Cre-lox-P system and a Pdx1-Cre transgenic line (PERαKO−/−), we previously reported that islet ERα suppresses islet glucolipotoxicity and prevents β-cell dysfunction induced by high fat feeding. We also showed that E2 acts via ERα to prevent β-cell apoptosis in vivo. However, the contribution of the islet ERα to β-cell survival in vivo, without the contribution of ERα in other tissues is still unclear. Using the PERαKO−/− mouse, we show that ERα mRNA expression is only decreased by 20% in the arcuate nucleus of the hypothalamus, without a parallel decrease in the VMH, making it a reliable model of pancreas-specific ERα elimination. Following exposure to alloxan-induced oxidative stress in vivo, female and male PERαKO−/− mice exhibited a predisposition to β-cell destruction and insulin deficient diabetes. In male PERαKO−/− mice, exposure to E2 partially prevented alloxan-induced β-cell destruction and diabetes. ERα mRNA expression was induced by hyperglycemia in vivo in islets from young mice as well as in cultured rat islets. The induction of ERα mRNA by hyperglycemia was retained in insulin receptor-deficient β-cells, demonstrating independence from direct insulin regulation. These findings suggest that induction of ERα expression acts to naturally protect β-cells against oxidative injury. PMID:24498408

  6. Monomethylated-adenines potentiate glucose-induced insulin production and secretion via inhibition of phosphodiesterase activity in rat pancreatic islets.

    PubMed

    Boland, Brandon B; Alarcón, Cristina; Ali, Almas; Rhodes, Christopher J

    2015-01-01

    Monomethyladenines have effects on DNA repair, G-protein-coupled receptor antagonism and autophagy. In islet ß-cells, 3-methyladenine (3-MA) has been implicated in DNA-repair and autophagy, but its mechanism of action is unclear. Here, the effect of monomethylated adenines was examined in rat islets. 3-MA, N6-methyladenine (N6-MA) and 9-methyladenine (9-MA), but not 1- or 7-monomethylated adenines, specifically potentiated glucose-induced insulin secretion (3-4 fold; p ≤ 0.05) and proinsulin biosynthesis (∼2-fold; p ≤ 0.05). Using 3-MA as a 'model' monomethyladenine, it was found that 3-MA augmented [cAMP]i accumulation (2-3 fold; p ≤ 0.05) in islets within 5 minutes. The 3-, N6- and 9-MA also enhanced glucose-induced phosphorylation of the cAMP/protein kinase-A (PKA) substrate cAMP-response element binding protein (CREB). Treatment of islets with pertussis or cholera toxin indicated 3-MA mediated elevation of [cAMP]i was not mediated via G-protein-coupled receptors. Also, 3-MA did not compete with 9-cyclopentyladenine (9-CPA) for adenylate cyclase inhibition, but did for the pan-inhibitor of phosphodiesterase (PDE), 3-isobutyl-1-methylxanthine (IBMX). Competitive inhibition experiments with PDE-isoform specific inhibitors suggested 3-MA to have a preference for PDE4 in islet ß-cells, but this was likely reflective of PDE4 being the most abundant PDE isoform in ß-cells. In vitro enzyme assays indicated that 3-, N6- and 9-MA were capable of inhibiting most PDE isoforms found in ß-cells. Thus, in addition to known inhibition of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3'K)/m Target of Rapamycin (mTOR) signaling, 3-MA also acts as a pan-phosphodiesterase inhibitor in pancreatic ß-cells to elevate [cAMP]i and then potentiate glucose-induced insulin secretion and production in parallel.

  7. 12-Lipoxygenase Promotes Obesity-Induced Oxidative Stress in Pancreatic Islets

    PubMed Central

    Maier, Bernhard; Nishiki, Yurika; Maganti, Aarthi V.; Nadler, Jerry L.

    2014-01-01

    High-fat diets lead to obesity, inflammation, and dysglycemia. 12-Lipoxygenase (12-LO) is activated by high-fat diets and catalyzes the oxygenation of cellular arachidonic acid to form proinflammatory intermediates. We hypothesized that 12-LO in the pancreatic islet is sufficient to cause dysglycemia in the setting of high-fat feeding. To test this, we generated pancreas-specific 12-LO knockout mice and studied their metabolic and molecular adaptations to high-fat diets. Whereas knockout mice and control littermates displayed identical weight gain, body fat distribution, and macrophage infiltration into fat, knockout mice exhibited greater adaptive islet hyperplasia, improved insulin secretion, and complete protection from dysglycemia. At the molecular level, 12-LO deletion resulted in increases in islet antioxidant enzymes Sod1 and Gpx1 in response to high-fat feeding. The absence or inhibition of 12-LO led to increases in nuclear Nrf2, a transcription factor responsible for activation of genes encoding antioxidant enzymes. Our data reveal a novel pathway in which islet 12-LO suppresses antioxidant enzymes and prevents the adaptive islet responses in the setting of high-fat diets. PMID:25071151

  8. Oxygen environment and islet size are the primary limiting factors of isolated pancreatic islet survival.

    PubMed

    Komatsu, Hirotake; Cook, Colin; Wang, Chia-Hao; Medrano, Leonard; Lin, Henry; Kandeel, Fouad; Tai, Yu-Chong; Mullen, Yoko

    2017-01-01

    Type 1 diabetes is an autoimmune disease that destroys insulin-producing beta cells in the pancreas. Pancreatic islet transplantation could be an effective treatment option for type 1 diabetes once several issues are resolved, including donor shortage, prevention of islet necrosis and loss in pre- and post-transplantation, and optimization of immunosuppression. This study seeks to determine the cause of necrotic loss of isolated islets to improve transplant efficiency. The oxygen tension inside isolated human islets of different sizes was simulated under varying oxygen environments using a computational in silico model. In vitro human islet viability was also assessed after culturing in different oxygen conditions. Correlation between simulation data and experimentally measured islet viability was examined. Using these in vitro viability data of human islets, the effect of islet diameter and oxygen tension of the culture environment on islet viability was also analyzed using a logistic regression model. Computational simulation clearly revealed the oxygen gradient inside the islet structure. We found that oxygen tension in the islet core was greatly lower (hypoxic) than that on the islet surface due to the oxygen consumption by the cells. The hypoxic core was expanded in the larger islets or in lower oxygen cultures. These findings were consistent with results from in vitro islet viability assays that measured central necrosis in the islet core, indicating that hypoxia is one of the major causes of central necrosis. The logistic regression analysis revealed a negative effect of large islet and low oxygen culture on islet survival. Hypoxic core conditions, induced by the oxygen gradient inside islets, contribute to the development of central necrosis of human isolated islets. Supplying sufficient oxygen during culture could be an effective and reasonable method to maintain isolated islets viable.

  9. Oxygen free-radical scavengers and immune destruction of murine islets in allograft rejection and multiple low-dose streptozocin-induced insulitis.

    PubMed

    Mendola, J; Wright, J R; Lacy, P E

    1989-03-01

    We examined the effects of desferrioxamine (DFX), a potent inhibitor of the formation of oxygen-derived hydroxyl radicals, and nicotinamide (NIC), a poly(ADP-ribose) synthetase inhibitor and a weak free-radical scavenger, on two models of immune destruction of murine islets [i.e., allograft rejection and multiple low-dose streptozocin (STZ)-induced insulitis]. Freshly isolated or low-temperature-cultured BALB/cJ islets were transplanted beneath the kidney capsules of C57BL/6J recipients. The recipients were treated with NIC alone (500 mg.kg-1.day-1), DFX alone (4.2 mg/day x 14 days), or NIC + DFX. Only recipients treated with NIC + DFX, receiving cultured islets, showed a mean graft survival time significantly longer than control mice receiving freshly isolated or cultured islets. Control CD-1 mice treated with multiple low doses of STZ developed insulitis and diabetes. Treatment with NIC alone, DFX alone, or NIC + DFX decreased the severity of hyperglycemia relative to the controls. Treatment with DFX alone was more effective than NIC alone or NIC + DFX. Only the group treated with DFX alone had a lower incidence of diabetes (mean plasma glucose level greater than 200 mg/dl) than the controls after 4 wk. Histologically, islets from control mice showed severe insulitis, islet destruction, and absence of stainable insulin, whereas islets from DFX-treated mice showed only mild peri-insulitis and a relative preservation of beta-cell granulation. Our study showed that NIC and DFX partially protect islets from immune destruction in allograft rejection and in low-dose STZ-induced insulitis. Apparently, hydroxyl radicals play important roles in both of these models.

  10. Glutathione Ethyl Ester Supplementation during Pancreatic Islet Isolation Improves Viability and Transplant Outcomes in a Murine Marginal Islet Mass Model

    PubMed Central

    Raposo do Amaral, Alexandre S.; Pawlick, Rena L.; Rodrigues, Erika; Costal, Flavia; Pepper, Andrew; Ferreira Galvão, Flávio H.; Correa-Giannella, Maria Lucia; Shapiro, A. M.James

    2013-01-01

    Background The success of pancreatic islet transplantation still faces many challenges, mainly related to cell damage during islet isolation and early post-transplant. The increased generation of reactive oxygen species (ROS) during islet isolation and the consumption of antioxidant defenses appear to be an important pathway related to islet damage. Methodology/Principal Findings In the present study we evaluated whether supplementation of glutathione-ethyl-ester (GEE) during islet isolation could improve islet viability and transplant outcomes in a murine marginal islet mass model. We also cultured human islets for 24 hours in standard CMRL media with or without GEE supplementation. Supplementation of GEE decreased the content of ROS in isolated islets, leading to a decrease in apoptosis and maintenance of islet viability. A higher percentage of mice transplanted with a marginal mass of GEE treated islets became euglycemic after transplant. The supplementation of 20 mM GEE in cultured human islets significantly reduced the apoptosis rate in comparison to untreated islets. Conclusions/Significance GEE supplementation was able to decrease the apoptosis rate and intracellular content of ROS in isolated islets and might be considered a potential intervention to improve islet viability during the isolation process and maintenance in culture before islet transplantation. PMID:23424628

  11. Glucose- and Hormone-Induced cAMP Oscillations in α- and β-Cells Within Intact Pancreatic Islets

    PubMed Central

    Tian, Geng; Sandler, Stellan; Gylfe, Erik; Tengholm, Anders

    2011-01-01

    OBJECTIVE cAMP is a critical messenger for insulin and glucagon secretion from pancreatic β- and α-cells, respectively. Dispersed β-cells show cAMP oscillations, but the signaling kinetics in cells within intact islets of Langerhans is unknown. RESEARCH DESIGN AND METHODS The subplasma-membrane cAMP concentration ([cAMP]pm) was recorded in α- and β-cells in the mantle of intact mouse pancreatic islets using total internal reflection microscopy and a fluorescent translocation biosensor. Cell identification was based on the opposite effects of adrenaline on cAMP in α- and β-cells. RESULTS In islets exposed to 3 mmol/L glucose, [cAMP]pm was low and stable. Glucagon and glucagon-like peptide-1(7-36)-amide (GLP-1) induced dose-dependent elevation of [cAMP]pm, often with oscillations synchronized among β-cells. Whereas glucagon also induced [cAMP]pm oscillations in most α-cells, <20% of the α-cells responded to GLP-1. Elevation of the glucose concentration to 11–30 mmol/L in the absence of hormones induced slow [cAMP]pm oscillations in both α- and β-cells. These cAMP oscillations were coordinated with those of the cytoplasmic Ca2+ concentration ([Ca2+]i) in the β-cells but not caused by the changes in [Ca2+]i. The transmembrane adenylyl cyclase (AC) inhibitor 2′5′-dideoxyadenosine suppressed the glucose- and hormone-induced [cAMP]pm elevations, whereas the preferential inhibitors of soluble AC, KH7, and 1,3,5(10)-estratrien-2,3,17-β-triol perturbed cell metabolism and lacked effect, respectively. CONCLUSIONS Oscillatory [cAMP]pm signaling in secretagogue-stimulated β-cells is maintained within intact islets and depends on transmembrane AC activity. The discovery of glucose- and glucagon-induced [cAMP]pm oscillations in α-cells indicates the involvement of cAMP in the regulation of pulsatile glucagon secretion. PMID:21444924

  12. Muscle damage induced by electrical stimulation.

    PubMed

    Nosaka, Kazunori; Aldayel, Abdulaziz; Jubeau, Marc; Chen, Trevor C

    2011-10-01

    Electrical stimulation (ES) induces muscle damage that is characterised by histological alterations of muscle fibres and connective tissue, increases in circulating creatine kinase (CK) activity, decreases in muscle strength and development of delayed onset muscle soreness (DOMS). Muscle damage is induced not only by eccentric contractions with ES but also by isometric contractions evoked by ES. Muscle damage profile following 40 isometric contractions of the knee extensors is similar between pulsed current (75 Hz, 400 μs) and alternating current (2.5 kHz delivered at 75 Hz, 400 μs) ES for similar force output. When comparing maximal voluntary and ES-evoked (75 Hz, 200 μs) 50 isometric contractions of the elbow flexors, ES results in greater decreases in maximal voluntary contraction strength, increases in plasma CK activity and DOMS. It appears that the magnitude of muscle damage induced by ES-evoked isometric contractions is comparable to that induced by maximal voluntary eccentric contractions, although the volume of affected muscles in ES is not as large as that of eccentric exercise-induced muscle damage. It seems likely that the muscle damage in ES is associated with high mechanical stress on the activated muscle fibres due to the specificity of motor unit recruitment (i.e., non-selective, synchronous and spatially fixed manner). The magnitude of muscle damage induced by ES is significantly reduced when the second ES bout is performed 2-4 weeks later. It is possible to attenuate the magnitude of muscle damage by "pre-conditioning" muscles, so that muscle damage should not limit the use of ES in training and rehabilitation.

  13. Quantifying pulsed laser induced damage to graphene

    SciTech Connect

    Currie, Marc; Caldwell, Joshua D.; Bezares, Francisco J.; Robinson, Jeremy; Anderson, Travis; Chun, Hayden; Tadjer, Marko

    2011-11-21

    As an emerging optical material, graphene's ultrafast dynamics are often probed using pulsed lasers yet the region in which optical damage takes place is largely uncharted. Here, femtosecond laser pulses induced localized damage in single-layer graphene on sapphire. Raman spatial mapping, SEM, and AFM microscopy quantified the damage. The resulting size of the damaged area has a linear correlation with the optical fluence. These results demonstrate local modification of sp{sup 2}-carbon bonding structures with optical pulse fluences as low as 14 mJ/cm{sup 2}, an order-of-magnitude lower than measured and theoretical ablation thresholds.

  14. Blood-Induced Joint Damage

    PubMed Central

    Roosendaal, Goris; Jansen, Nathalie W.D.; Lafeber, Floris P.J.G.; Mastbergen, Simon C.

    2013-01-01

    Objective. Four days of blood exposure leads to irreversible cartilage damage in vitro. In contrast, intermittent intra-articular blood injections twice a week during 4 weeks (mimicking micro-bleeds) in a canine model resulted in transient damage only. In this study, it was evaluated whether acute joint bleeds are more harmful than micro-bleeds in a canine model of knee arthropathy. Design. Seven dogs received 4 sequential daily intra-articular blood injections twice in 2 weeks (mimicking 2 acute 4-day joint bleeds). Seven other dogs received the same blood load but in a total of 8 injections intermittently over the 4-week period with at least 1 day in between (mimicking micro-bleeds over the same timespan). Contralateral knees served as controls. Ten weeks after the last injection cartilage matrix turnover and synovial inflammation were evaluated. Results. Only after the acute joint bleeds the release of newly formed and total (resident) cartilage matrix glycosaminoglycans were increased (P = 0.04 and P = 0.01, respectively). Furthermore, in animals with the acute joint bleeds cartilage glycosaminoglycan content was decreased (P = 0.01) and not in animals with micro-bleeds. Mild synovial inflammation was observed in both groups (both P < 0.0001) but was not different between groups. Conclusions. In contrast to micro-bleeds, 2 acute joint bleeds lead to prolonged cartilage damage independent of the level of synovial inflammation. This model suggests that micro-bleeds are less devastating than acute joint bleeds with respect to joint damage, which might be of relevance to treatment of joint bleeds in clinical practice. PMID:26069675

  15. One year of sitagliptin treatment protects against islet amyloid-associated β-cell loss and does not induce pancreatitis or pancreatic neoplasia in mice.

    PubMed

    Aston-Mourney, Kathryn; Subramanian, Shoba L; Zraika, Sakeneh; Samarasekera, Thanya; Meier, Daniel T; Goldstein, Lynn C; Hull, Rebecca L

    2013-08-15

    The dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin is an attractive therapy for diabetes, as it increases insulin release and may preserve β-cell mass. However, sitagliptin also increases β-cell release of human islet amyloid polypeptide (hIAPP), the peptide component of islet amyloid, which is cosecreted with insulin. Thus, sitagliptin treatment may promote islet amyloid formation and its associated β-cell toxicity. Conversely, metformin treatment decreases islet amyloid formation by decreasing β-cell secretory demand and could therefore offset sitagliptin's potential proamyloidogenic effects. Sitagliptin treatment has also been reported to be detrimental to the exocrine pancreas. We investigated whether long-term sitagliptin treatment, alone or with metformin, increased islet amyloid deposition and β-cell toxicity and induced pancreatic ductal proliferation, pancreatitis, and/or pancreatic metaplasia/neoplasia. hIAPP transgenic and nontransgenic littermates were followed for 1 yr on no treatment, sitagliptin, metformin, or the combination. Islet amyloid deposition, β-cell mass, insulin release, and measures of exocrine pancreas pathology were determined. Relative to untreated mice, sitagliptin treatment did not increase amyloid deposition, despite increasing hIAPP release, and prevented amyloid-induced β-cell loss. Metformin treatment alone or with sitagliptin decreased islet amyloid deposition to a similar extent vs untreated mice. Ductal proliferation was not altered among treatment groups, and no evidence of pancreatitis, ductal metaplasia, or neoplasia were observed. Therefore, long-term sitagliptin treatment stimulates β-cell secretion without increasing amyloid formation and protects against amyloid-induced β-cell loss. This suggests a novel effect of sitagliptin to protect the β-cell in type 2 diabetes that appears to occur without adverse effects on the exocrine pancreas.

  16. One year of sitagliptin treatment protects against islet amyloid-associated β-cell loss and does not induce pancreatitis or pancreatic neoplasia in mice

    PubMed Central

    Aston-Mourney, Kathryn; Subramanian, Shoba L.; Zraika, Sakeneh; Samarasekera, Thanya; Meier, Daniel T.; Goldstein, Lynn C.

    2013-01-01

    The dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin is an attractive therapy for diabetes, as it increases insulin release and may preserve β-cell mass. However, sitagliptin also increases β-cell release of human islet amyloid polypeptide (hIAPP), the peptide component of islet amyloid, which is cosecreted with insulin. Thus, sitagliptin treatment may promote islet amyloid formation and its associated β-cell toxicity. Conversely, metformin treatment decreases islet amyloid formation by decreasing β-cell secretory demand and could therefore offset sitagliptin's potential proamyloidogenic effects. Sitagliptin treatment has also been reported to be detrimental to the exocrine pancreas. We investigated whether long-term sitagliptin treatment, alone or with metformin, increased islet amyloid deposition and β-cell toxicity and induced pancreatic ductal proliferation, pancreatitis, and/or pancreatic metaplasia/neoplasia. hIAPP transgenic and nontransgenic littermates were followed for 1 yr on no treatment, sitagliptin, metformin, or the combination. Islet amyloid deposition, β-cell mass, insulin release, and measures of exocrine pancreas pathology were determined. Relative to untreated mice, sitagliptin treatment did not increase amyloid deposition, despite increasing hIAPP release, and prevented amyloid-induced β-cell loss. Metformin treatment alone or with sitagliptin decreased islet amyloid deposition to a similar extent vs untreated mice. Ductal proliferation was not altered among treatment groups, and no evidence of pancreatitis, ductal metaplasia, or neoplasia were observed. Therefore, long-term sitagliptin treatment stimulates β-cell secretion without increasing amyloid formation and protects against amyloid-induced β-cell loss. This suggests a novel effect of sitagliptin to protect the β-cell in type 2 diabetes that appears to occur without adverse effects on the exocrine pancreas. PMID:23736544

  17. Consumption of a glucose diet enhances the sensitivity of pancreatic islets from adrenalectomized genetically obese (ob/ob) mice to glucose-induced insulin secretion.

    PubMed

    Mistry, A M; Chen, N G; Lee, Y S; Romsos, D R

    1995-03-01

    Consumption of a glucose diet for 4 d markedly elevates plasma insulin concentrations in adrenalectomized ob/ob mice. The present study examined regulation of insulin secretion from perifused pancreatic islets of female adrenalectomized genetically obese (ob/ob) and lean mice fed a glucose diet for 4 d. These mice were fed a high carbohydrate commercial diet for 21 d, or the high carbohydrate commercial diet for 17 d and a purified high glucose diet for the last 4 d of the 21-d feeding period. Adrenalectomy equalized plasma insulin concentrations, pancreatic islet size, rates of insulin secretion in response to 20 mmol/L glucose and insulin mRNA relative abundance in ob/ob and lean mice fed the commercial diet, but the threshold for glucose-induced insulin secretion determined by a linear glucose gradient remained lower in islets from adrenalectomized ob/ob mice than in those from lean mice (3.8 +/- 0.1 vs. 4.9 +/- 0.2 mmol/L glucose), and addition of acetylcholine to the perifusate lowered the threshold to only 2.0 +/- 0.1 mmol/L glucose in islets from ob/ob mice vs. 3.3 +/- 0.1 mmol/L glucose in lean mice. Switching from the commercial diet to the glucose diet for 4 d increased plasma insulin concentrations -10-fold in islets from adrenalectomized ob/ob mice without affecting islet size, 20 mmol/L glucose-induced insulin secretion or insulin mRNA abundance. Consumption of the glucose diet did, however, markedly lower the threshold for glucose-induced insulin secretion in islets from adrenalectomized ob/ob mice to approximate the abnormally low glucose thresholds in intact ob/ob mice.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Human interleukin-1 beta induced stimulation of insulin release from rat pancreatic islets is accompanied by an increase in mitochondrial oxidative events.

    PubMed

    Eizirik, D L; Sandler, S

    1989-11-01

    Acute exposure of pancreatic islets to interleukin-1 beta results in an increase in insulin release, while an extension of the exposure time induces a functional suppression and eventually, destruction of the B-cells. We have recently suggested that the interleukin-1 beta induced inhibition of islet function is mediated through an impairment in oxidative metabolism. The aim of the current study was to investigate if the acute, stimulatory effects of interleukin-1 beta on islet function could also be related to changes in the substrate metabolism. For this purpose, rat islets were exposed for 90-120 min to 30 pmol/l human recombinant interleukin-1 beta (biological activity of 2.5 U/ml) and their function and metabolism characterized during this period. The cytokine did not increase insulin release in the presence of 1.7 or 5.5 mmol/l glucose but in both the presence of 16.7 mmol/l glucose or 10 mmol/l leucine + 2 mmol/l glutamine there was a 50% increase in insulin release. Interleukin-1 beta exposure increased the oxidation of D-[U-14C]glucose at 5.5 mmol/l glucose by 25% and at 16.7 mmol/l glucose by 60%. Carbohydrate and amino acid metabolism were further examined in the presence of D-[5-3H]glucose, D-[6-14C]glucose, [1-14C]pyruvate, L-[U-14C]glutamine, L-[U-14C]leucine and L-[1-14C]leucine. There was no difference between control islets and interleukin-1 beta exposed islets in terms of D-[5-3H]glucose utilization or [1-14C]pyruvate decarboxylation, but the oxidation of D-[6-14C]glucose was increased by 64% in the interleukin-1 beta exposed islets.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. Triplex-induced DNA damage response.

    PubMed

    Rogers, Faye A; Tiwari, Meetu Kaushik

    2013-12-13

    Cellular DNA damage response is critical to preserving genomic integrity following exposure to genotoxic stress. A complex series of networks and signaling pathways become activated after DNA damage and trigger the appropriate cellular response, including cell cycle arrest, DNA repair, and apoptosis. The response elicited is dependent upon the type and extent of damage sustained, with the ultimate goal of preventing propagation of the damaged DNA. A major focus of our studies is to determine the cellular pathways involved in processing damage induced by altered helical structures, specifically triplexes. Our lab has demonstrated that the TFIIH factor XPD occupies a central role in triggering apoptosis in response to triplex-induced DNA strand breaks. We have shown that XPD co-localizes with γH2AX, and its presence is required for the phosphorylation of H2AX tyrosine142, which stimulates the signaling pathway to recruit pro-apoptotic factors to the damage site. Herein, we examine the cellular pathways activated in response to triplex formation and discuss our finding that suggests that XPD-dependent apoptosis plays a role in preserving genomic integrity in the presence of excessive structurally induced DNA damage.

  20. Autophagy in light-induced retinal damage.

    PubMed

    Chen, Yu; Perusek, Lindsay; Maeda, Akiko

    2016-03-01

    Vision is reliant upon converting photon signals to electrical information which is interpreted by the brain and therefore allowing us to receive information about our surroundings. However, when exposed to excessive light, photoreceptors and other types of cells in the retina can undergo light-induced cell death, termed light-induced retinal damage. In this review, we summarize our current knowledge regarding molecular events in the retina after excessive light exposure and mechanisms of light-induced retinal damage. We also introduce works which investigate potential roles of autophagy, an essential cellular mechanism required for maintaining homeostasis under stress conditions, in the illuminated retina and animal models of light-induced retinal damage.

  1. Autophagy in light-induced retinal damage

    PubMed Central

    Chen, Yu; Perusek, Lindsay; Maeda, Akiko

    2015-01-01

    Vision is reliant upon converting photon signals to electrical information which is interpreted by the brain and therefore allowing us to receive information about our surroundings. However, when exposed to excessive light, photoreceptors and other types of cells in the retina can undergo light-induced cell death, termed light-induced retinal damage. In this review, we summarize our current knowledge regarding molecular events in the retina after excessive light exposure and mechanisms of light-induced retinal damage. We also introduce works which investigate potential roles of autophagy, an essential cellular mechanism required for maintaining homeostasis under stress conditions, in the illuminated retina and animal models of light-induced retinal damage. PMID:26325327

  2. In vitro reconstitution of pancreatic islets.

    PubMed

    Kojima, Nobuhiko

    2014-01-01

    The lack of transplantable pancreatic islets is a serious problem that affects the treatment of patients with type 1 diabetes mellitus. Beta cells can be induced from various sources of stem or progenitor cells, including induced pluripotent stem cells in the near future; however, the reconstitution of islets from β cells in culture dishes is challenging. The generation of highly functional islets may require three-dimensional spherical cultures that resemble intact islets. This review discusses recent advances in the reconstitution of islets. Several factors affect the reconstitution of pseudoislets with higher functions, such as architectural similarity, cell-to-cell contact, and the production method. The actual transplantation of naked or encapsulated pseudoislets and islet-like cell clusters from various stem cell sources is also discussed. Advancing our understanding of the methods used to reconstitute pseudoislets should expand the range of potential strategies available for developing de novo islets for therapeutic applications.

  3. β Cell–specific increased expression of calpastatin prevents diabetes induced by islet amyloid polypeptide toxicity

    PubMed Central

    Gurlo, Tatyana; Costes, Safia; Hoang, Jonathan D.; Rivera, Jacqueline F.; Butler, Alexandra E.; Butler, Peter C.

    2016-01-01

    The islet in type 2 diabetes (T2D) shares many features of the brain in protein misfolding diseases. There is a deficit of β cells with islet amyloid derived from islet amyloid polypeptide (IAPP), a protein coexpressed with insulin. Small intracellular membrane-permeant oligomers, the most toxic form of IAPP, are more frequent in β cells of patients with T2D and rodents expressing human IAPP. β Cells in T2D, and affected cells in neurodegenerative diseases, share a comparable pattern of molecular pathology, including endoplasmic reticulum stress, mitochondrial dysfunction, attenuation of autophagy, and calpain hyperactivation. While this adverse functional cascade in response to toxic oligomers is well described, the sequence of events and how best to intervene is unknown. We hypothesized that calpain hyperactivation is a proximal event and tested this in vivo by β cell–specific suppression of calpain hyperactivation with calpastatin overexpression in human IAPP transgenic mice. β Cell–specific calpastatin overexpression was remarkably protective against β cell dysfunction and loss and diabetes onset. The critical autophagy/lysosomal pathway for β cell viability was protected with calpain suppression, consistent with findings in models of neurodegenerative diseases. We conclude that suppression of calpain hyperactivation is a potentially beneficial disease-modifying strategy for protein misfolding diseases, including T2D. PMID:27812546

  4. Resveratrol supplementation restores high-fat diet-induced insulin secretion dysfunction by increasing mitochondrial function in islet

    PubMed Central

    Kong, Wen; Zheng, Juan; Zhang, Hao-hao; Hu, Xiang; Zeng, Tian-shu; Hu, Di

    2015-01-01

    Resveratrol (RSV), a natural compound, is known for its effects on energy homeostasis. Here we investigated the effects of RSV and possible mechanism in insulin secretion of high-fat diet rats. Rats were randomly divided into three groups as follows: NC group (animals were fed ad libitum with normal chow for 8 weeks), HF group (animals were fed ad libitum with high-fat diet for 8 weeks), and HFR group (animals were treated with high-fat diet and administered with RSV for 8 weeks). Insulin secretion ability of rats was assessed by hyperglycemic clamp. Mitochondrial biogenesis genes, mitochondrial respiratory chain activities, reactive oxidative species (ROS), and several mitochondrial antioxidant enzyme activities were evaluated in islet. We found that HF group rats clearly showed low insulin secretion and mitochondrial complex dysfunction. Expression of silent mating type information regulation 2 homolog- 1 (SIRT1) and related mitochondrial biogenesis were significantly decreased. However, RSV administration group (HFR) showed a marked potentiation of glucose-stimulated insulin secretion. This effect was associated with elevated SIRT1 protein expression and antioxidant enzyme activities, resulting in increased mitochondrial respiratory chain activities and decreased ROS level. This study suggests that RSV may increase islet mitochondrial complex activities and antioxidant function to restore insulin secretion dysfunction induced by high-fat diet. PMID:25228148

  5. Resveratrol supplementation restores high-fat diet-induced insulin secretion dysfunction by increasing mitochondrial function in islet.

    PubMed

    Kong, Wen; Chen, Lu-lu; Zheng, Juan; Zhang, Hao-hao; Hu, Xiang; Zeng, Tian-shu; Hu, Di

    2015-02-01

    Resveratrol (RSV), a natural compound, is known for its effects on energy homeostasis. Here we investigated the effects of RSV and possible mechanism in insulin secretion of high-fat diet rats. Rats were randomly divided into three groups as follows: NC group (animals were fed ad libitum with normal chow for 8 weeks), HF group (animals were fed ad libitum with high-fat diet for 8 weeks), and HFR group (animals were treated with high-fat diet and administered with RSV for 8 weeks). Insulin secretion ability of rats was assessed by hyperglycemic clamp. Mitochondrial biogenesis genes, mitochondrial respiratory chain activities, reactive oxidative species (ROS), and several mitochondrial antioxidant enzyme activities were evaluated in islet. We found that HF group rats clearly showed low insulin secretion and mitochondrial complex dysfunction. Expression of silent mating type information regulation 2 homolog- 1 (SIRT1) and related mitochondrial biogenesis were significantly decreased. However, RSV administration group (HFR) showed a marked potentiation of glucose-stimulated insulin secretion. This effect was associated with elevated SIRT1 protein expression and antioxidant enzyme activities, resulting in increased mitochondrial respiratory chain activities and decreased ROS level. This study suggests that RSV may increase islet mitochondrial complex activities and antioxidant function to restore insulin secretion dysfunction induced by high-fat diet. © 2014 by the Society for Experimental Biology and Medicine.

  6. Islet Endothelial Cells Induce Glycosylation and Increase Cell-surface Expression of Integrin β1 in β Cells*

    PubMed Central

    Spelios, Michael G.; Olsen, John A.; Kenna, Lauren A.; Akirav, Eitan M.

    2015-01-01

    The co-culturing of insulinoma and islet-derived endothelial cell (iEC) lines results in the spontaneous formation of free-floating pseudoislets (PIs). We previously showed that iEC-induced PIs display improved insulin expression and secretion in response to glucose stimulation. This improvement was associated with a de novo deposition of extracellular matrix (ECM) proteins by iECs in and around the PIs. Here, iEC-induced PIs were used to study the expression and posttranslational modification of the ECM receptor integrin β1. A wide array of integrin β subunits was detected in βTC3 and NIT-1 insulinomas as well as in primary islets, with integrin β1 mRNA and protein detected in all three cell types. Interestingly, the formation of iEC-induced PIs altered the glycosylation patterns of integrin β1, resulting in a higher molecular weight form of the receptor. This form was found in native pancreas but was completely absent in monolayer β-cells. Fluorescence-activated cell sorting analysis of monolayers and PIs revealed a higher expression of integrin β1 in PIs. Antibody-mediated blocking of integrin β1 led to alterations in β-cell morphology, reduced insulin gene expression, and enhanced glucose secretion under baseline conditions. These results suggest that iEC-induced PI formation may alter integrin β1 expression and posttranslational modification by enhancing glycosylation, thereby providing a more physiological culture system for studying integrin-ECM interactions in β cells. PMID:25911095

  7. Transient overexpression of cyclin D2/CDK4/GLP1 genes induces proliferation and differentiation of adult pancreatic progenitors and mediates islet regeneration.

    PubMed

    Chen, Shuyuan; Shimoda, Masayuki; Chen, Jiaxi; Matsumoto, Shinichi; Grayburn, Paul A

    2012-02-15

    The molecular mechanism of β-cell regeneration remains poorly understood. Cyclin D2/CDK4 expresses in normal β cells and maintains adult β-cell growth. We hypothesized that gene therapy with cyclin D2/CDK4/GLP-1 plasmids targeted to the pancreas of STZ-treated rats by ultrasound-targeted microbubble destruction (UTMD) would force cell cycle re-entry of residual G(0)-phase islet cells into G(1)/S phase to regenerate β cells. A single UTMD treatment induced β-cell regeneration with reversal of diabetes for 6 mo without evidence of toxicity. We observed that this β-cell regeneration was not mediated by self-replication of pre-existing β cells. Instead, cyclin D2/CDK4/GLP-1 initiated robust proliferation of adult pancreatic progenitor cells that exist within islets and terminally differentiate to mature islets with β cells and α cells.

  8. Femtosecond Laser-Induced Damage of Dielectrics

    NASA Astrophysics Data System (ADS)

    Lenzner, M.

    Optical damage in non-metals (dielectrics) may severely affect the performance of high-power laser systems as well as the efficiency of optical systems based on nonlinear processes and has therefore been subject to extensive research for some 30 years. The current knowledge of laser-induced optical damage in these materials is reviewed. Emphasis is placed on the recent extension of available experimental data into the femtosecond range. Recent results are presented achieved with a sub-10 fs laser system which explores the limits of time resolution as well as the limit of intensities that a solid can sustain without irreversible damage. It is concluded that sub-10fs laser pulses open up the way to reversible nonperturbative nonlinear optics at intensities greater than 1014 W/cm2 (slightly below damage threshold) and to nanometer-precision laser ablation (slightly above threshold) in dielectric materials.

  9. Metformin Ameliorates Dysfunctional Traits of Glibenclamide- and Glucose-Induced Insulin Secretion by Suppression of Imposed Overactivity of the Islet Nitric Oxide Synthase-NO System.

    PubMed

    Lundquist, Ingmar; Mohammed Al-Amily, Israa; Meidute Abaraviciene, Sandra; Salehi, Albert

    2016-01-01

    Metformin lowers diabetic blood glucose primarily by reducing hepatic gluconeogenesis and increasing peripheral glucose uptake. However, possible effects by metformin on beta-cell function are incompletely understood. We speculated that metformin might positively influence insulin secretion through impacting the beta-cell nitric oxide synthase (NOS)-NO system, a negative modulator of glucose-stimulated insulin release. In short-time incubations with isolated murine islets either glibenclamide or high glucose augmented insulin release associated with increased NO production from both neural and inducible NOS. Metformin addition suppressed the augmented NO generation coinciding with amplified insulin release. Islet culturing with glibenclamide or high glucose revealed pronounced fluorescence of inducible NOS in the beta-cells being abolished by metformin co-culturing. These findings were reflected in medium nitrite-nitrate levels. A glucose challenge following islet culturing with glibenclamide or high glucose revealed markedly impaired insulin response. Metformin co-culturing restored this response. Culturing murine islets and human islets from controls and type 2 diabetics with high glucose or high glucose + glibenclamide induced a pronounced decrease of cell viability being remarkably restored by metformin co-culturing. We show here, that imposed overactivity of the beta-cell NOS-NO system by glibenclamide or high glucose leads to insulin secretory dysfunction and reduced cell viability and also, importantly, that these effects are relieved by metformin inhibiting beta-cell NO overproduction from both neural and inducible NOS thus ameliorating a concealed negative influence by NO induced by sulfonylurea treatment and/or high glucose levels. This double-edged effect of glibenclamide on the beta-cellsuggests sulfonylurea monotherapy in type 2 diabetes being avoided.

  10. Metformin Ameliorates Dysfunctional Traits of Glibenclamide- and Glucose-Induced Insulin Secretion by Suppression of Imposed Overactivity of the Islet Nitric Oxide Synthase-NO System

    PubMed Central

    Lundquist, Ingmar; Mohammed Al-Amily, Israa; Meidute Abaraviciene, Sandra

    2016-01-01

    Metformin lowers diabetic blood glucose primarily by reducing hepatic gluconeogenesis and increasing peripheral glucose uptake. However, possible effects by metformin on beta-cell function are incompletely understood. We speculated that metformin might positively influence insulin secretion through impacting the beta-cell nitric oxide synthase (NOS)-NO system, a negative modulator of glucose-stimulated insulin release. In short-time incubations with isolated murine islets either glibenclamide or high glucose augmented insulin release associated with increased NO production from both neural and inducible NOS. Metformin addition suppressed the augmented NO generation coinciding with amplified insulin release. Islet culturing with glibenclamide or high glucose revealed pronounced fluorescence of inducible NOS in the beta-cells being abolished by metformin co-culturing. These findings were reflected in medium nitrite-nitrate levels. A glucose challenge following islet culturing with glibenclamide or high glucose revealed markedly impaired insulin response. Metformin co-culturing restored this response. Culturing murine islets and human islets from controls and type 2 diabetics with high glucose or high glucose + glibenclamide induced a pronounced decrease of cell viability being remarkably restored by metformin co-culturing. We show here, that imposed overactivity of the beta-cell NOS-NO system by glibenclamide or high glucose leads to insulin secretory dysfunction and reduced cell viability and also, importantly, that these effects are relieved by metformin inhibiting beta-cell NO overproduction from both neural and inducible NOS thus ameliorating a concealed negative influence by NO induced by sulfonylurea treatment and/or high glucose levels. This double-edged effect of glibenclamide on the beta-cellsuggests sulfonylurea monotherapy in type 2 diabetes being avoided. PMID:27820841

  11. Laser-Induced Damage with Femtosecond Pulses

    NASA Astrophysics Data System (ADS)

    Kafka, Kyle R. P.

    The strong electric fields of focused femtosecond laser pulses lead to non-equilibrium dynamics in materials, which, beyond a threshold intensity, causes laser-induced damage (LID). Such a strongly non-linear and non-perturbative process renders important LID observables like fluence and intensity thresholds and damage morphology (crater) extremely difficult to predict quantitatively. However, femtosecond LID carries a high degree of precision, which has been exploited in various micro/nano-machining and surface engineering applications, such as human eye surgery and super-hydrophobic surfaces. This dissertation presents an array of experimental studies which have measured the damage behavior of various materials under femtosecond irradiation. Precision experiments were performed to produce extreme spatio-temporal confinement of the femtosecond laser-solid damage interaction on monocrystalline Cu, which made possible the first successful direct-benchmarking of LID simulation with realistic damage craters. A technique was developed to produce laser-induced periodic surface structures (LIPSS) in a single pulse (typically a multi-pulse phenomenon), and was used to perform a pump-probe study which revealed asynchronous LIPSS formation on copper. Combined with 1-D calculations, this new experimental result suggests more drastic electron heating than expected. Few-cycle pulses were used to study the LID performance and morphology of commercial ultra-broadband optics, which had not been systematically studied before. With extensive surface analysis, various morphologies were observed, including LIPSS, swelling (blisters), simple craters, and even ring-shaped structures, which varied depending on the coating design, number of pulses, and air/vacuum test environment. Mechanisms leading to these morphologies are discussed, many of which are ultrafast in nature. The applied damage behavior of multi-layer dielectric mirrors was measured and compared between long pulse (150 ps

  12. Continuous Quadrupole Magnetic Separation of Islets during Digestion Improves Purified Porcine Islet Viability

    PubMed Central

    Kumar Sajja, Venkata Sunil; Rizzari, Michael D.; Scott III, William E.; Kitzmann, Jennifer P.; Kennedy, David J.; Todd, Paul W.; Balamurugan, Appakalai N.; Hering, Bernhard J.

    2016-01-01

    Islet transplantation (ITx) is an emerging and promising therapy for patients with uncontrolled type 1 diabetes. The islet isolation and purification processes require exposure to extended cold ischemia, warm-enzymatic digestion, mechanical agitation, and use of damaging chemicals for density gradient separation (DG), all of which reduce viable islet yield. In this paper, we describe initial proof-of-concept studies exploring quadrupole magnetic separation (QMS) of islets as an alternative to DG to reduce exposure to these harsh conditions. Three porcine pancreata were split into two parts, the splenic lobe (SPL) and the combined connecting/duodenal lobes (CDL), for paired digestions and purifications. Islets in the SPL were preferentially labeled using magnetic microparticles (MMPs) that lodge within the islet microvasculature when infused into the pancreas and were continuously separated from the exocrine tissue by QMS during the collection phase of the digestion process. Unlabeled islets from the CDL were purified by conventional DG. Islets purified by QMS exhibited significantly improved viability (measured by oxygen consumption rate per DNA, p < 0.03) and better morphology relative to control islets. Islet purification by QMS can reduce the detrimental effects of prolonged exposure to toxic enzymes and density gradient solutions and substantially improve islet viability after isolation. PMID:27843954

  13. Continuous Quadrupole Magnetic Separation of Islets during Digestion Improves Purified Porcine Islet Viability.

    PubMed

    Weegman, Bradley P; Kumar Sajja, Venkata Sunil; Suszynski, Thomas M; Rizzari, Michael D; Scott Iii, William E; Kitzmann, Jennifer P; Mueller, Kate R; Hanley, Thomas R; Kennedy, David J; Todd, Paul W; Balamurugan, Appakalai N; Hering, Bernhard J; Papas, Klearchos K

    2016-01-01

    Islet transplantation (ITx) is an emerging and promising therapy for patients with uncontrolled type 1 diabetes. The islet isolation and purification processes require exposure to extended cold ischemia, warm-enzymatic digestion, mechanical agitation, and use of damaging chemicals for density gradient separation (DG), all of which reduce viable islet yield. In this paper, we describe initial proof-of-concept studies exploring quadrupole magnetic separation (QMS) of islets as an alternative to DG to reduce exposure to these harsh conditions. Three porcine pancreata were split into two parts, the splenic lobe (SPL) and the combined connecting/duodenal lobes (CDL), for paired digestions and purifications. Islets in the SPL were preferentially labeled using magnetic microparticles (MMPs) that lodge within the islet microvasculature when infused into the pancreas and were continuously separated from the exocrine tissue by QMS during the collection phase of the digestion process. Unlabeled islets from the CDL were purified by conventional DG. Islets purified by QMS exhibited significantly improved viability (measured by oxygen consumption rate per DNA, p < 0.03) and better morphology relative to control islets. Islet purification by QMS can reduce the detrimental effects of prolonged exposure to toxic enzymes and density gradient solutions and substantially improve islet viability after isolation.

  14. PANDER-induced cell-death genetic networks in islets reveal central role for caspase-3 and cyclin-dependent kinase inhibitor 1A (p21).

    PubMed

    Burkhardt, Brant R; Greene, Scott R; White, Peter; Wong, Ryan K; Brestelli, John E; Yang, Jichun; Robert, Claudia E; Brusko, Todd M; Wasserfall, Clive H; Wu, Jianmei; Atkinson, Mark A; Gao, Zhiyong; Kaestner, Klaus H; Wolf, Bryan A

    2006-03-15

    PANcreatic DERived factor is an islet-specific cytokine that promotes apoptosis in primary islets and islet cell lines. To elucidate the genetic mechanisms of PANDER-induced cell death we performed expression profiling using the mouse PancChip version 5.0 in conjunction with Ingenuity Pathway Analysis. Murine islets were treated with PANDER and differentially expressed genes were identified at 48 and 72 h post-treatment. 64 genes were differentially expressed in response to PANDER treatment. 22 genes are associated with cell death. In addition, the genes with the highest fold change were linked with cell death or apoptosis. The most significantly affected gene at 48 h was the downregulated cyclin-dependent kinase inhibitor 1A (CDKN1A or p21). Approximately half of the genes impacted at 72 h were linked to cell death. Cell death differentially expressed genes were confirmed by quantitative RT-PCR. Further analysis identified cell death genetic networks at both time points with 21 of the 22 cell death genes related in various biological pathways. Caspase-3 (CASP3) was biologically linked to CDKN1A in several genetic networks and these two genes were further examined. Elevated cleaved CASP3 levels in PANDER-treated beta-TC3 insulinoma cells were found to abrogate CDKN1A expression. Levels of CDKN1A were not affected in the absence of cleaved CASP3. PANDER-induced downregulation of CDKN1A expression coupled with induced CASP3-activation may serve a central role in islet cell death and offers further insight into the mechanisms of cytokine-induced beta-cell apoptosis.

  15. Long-term effects of nicotinamide-induced inhibition of poly(adenosine diphosphate-ribose) polymerase activity in rat pancreatic islets exposed to interleukin-1 beta.

    PubMed

    Reddy, S; Salari-Lak, N; Sandler, S

    1995-05-01

    Nicotinamide (NIC) is presently extensively studied as a potential agent that might prevent the development of insulin-dependent diabetes mellitus. This study aimed to examine the consequence of exposing isolated rat pancreatic islets to various concentrations of NIC (0, 0.5, 1.0, 5.0, 10, and 25 mM) over a prolonged period (6 days) in tissue culture and also to assess the efficacy of NIC to counteract interleukin-1 beta (IL-1; 25 U/ml)-induced beta-cell dysfunction. Except for a 30-40% increase at 5.0 mM NIC, the insulin content of islets was not affected by NIC. Also, the islet DNA content remained essentially unchanged. The insulin accumulation in the culture medium declined at 5-25 mM NIC between days 4-6. The insulin release in response to 16.7 mM glucose on day 6 was enhanced after culture with the addition of 0.5 mM NIC, but 25 mM NIC caused a strong inhibition of insulin secretion. However, neither the (pro)insulin nor the total protein biosynthesis rate of the islets was affected by NIC. A significant inhibition of the islet poly(ADP-ribose) polymerase activity by 40-80% was observed at 5-25 mM NIC. IL-1 was then tested together with 1.0 and 10 mM NIC. The islet DNA content was markedly reduced in all groups treated with IL-1, as was the medium insulin accumulation. Moreover, NIC failed to prevent IL-1 induced impairment of islet insulin release on day 6. The cytokine induced a very pronounced and sustained increase in the medium nitrite accumulation, and NIC could not influence this elevation. Thus, these data show that prolonged exposure to elevated NIC levels impaired the function of rat beta-cells, and NIC failed to counteract IL-1 actions. Whether these events are mimicked in the ongoing clinical trials with NIC remain to be established.

  16. Delayed apoptosis allows islet β-cells to implement an autophagic mechanism to promote cell survival

    PubMed Central

    Hayes, Heather L.; Peterson, Brett S.; Haldeman, Jonathan M.; Newgard, Christopher B.; Hohmeier, Hans E.

    2017-01-01

    Increased β-cell death coupled with the inability to replicate existing β-cells drives the decline in β-cell mass observed in the progression of both major forms of diabetes. Understanding endogenous mechanisms of islet cell survival could have considerable value for the development of novel strategies to limit β-cell loss and thereby promote β-cell recovery. Insulinoma cells have provided useful insight into β-cell death pathways but observations made in cell lines sometimes fail to translate to primary islets. Here, we report dramatic differences in the temporal regulation and engagement of the apoptotic program in primary rodent islets relative to the INS-1 derived 832/13 cell line. As expected, 832/13 cells rapidly induced cell stress markers in response to ER stress or DNA damage and were fully committed to apoptosis, resulting in >80% cell death within 24 h. In contrast, primary rat islets were largely refractory to cell death in response to ER stress and DNA damage, despite rapid induction of stress markers, such as XBP-1(s), CHOP, and PUMA. Gene expression profiling revealed a general suppression of pro-apoptotic machinery, such as Apaf-1 and caspase 3, and sustained levels of pro-survival factors, such as cIAP-1, cIAP-2, and XIAP, in rat islets. Furthermore, we observed sustained induction of autophagy following chronic ER stress and found that inhibition of autophagy rendered islet β-cells highly vulnerable to ER stress-induced cell death. We propose that islet β-cells dampen the apoptotic response to delay the onset of cell death, providing a temporal window in which autophagy can be activated to limit cellular damage and promote survival. PMID:28212395

  17. Delayed apoptosis allows islet β-cells to implement an autophagic mechanism to promote cell survival.

    PubMed

    Hayes, Heather L; Peterson, Brett S; Haldeman, Jonathan M; Newgard, Christopher B; Hohmeier, Hans E; Stephens, Samuel B

    2017-01-01

    Increased β-cell death coupled with the inability to replicate existing β-cells drives the decline in β-cell mass observed in the progression of both major forms of diabetes. Understanding endogenous mechanisms of islet cell survival could have considerable value for the development of novel strategies to limit β-cell loss and thereby promote β-cell recovery. Insulinoma cells have provided useful insight into β-cell death pathways but observations made in cell lines sometimes fail to translate to primary islets. Here, we report dramatic differences in the temporal regulation and engagement of the apoptotic program in primary rodent islets relative to the INS-1 derived 832/13 cell line. As expected, 832/13 cells rapidly induced cell stress markers in response to ER stress or DNA damage and were fully committed to apoptosis, resulting in >80% cell death within 24 h. In contrast, primary rat islets were largely refractory to cell death in response to ER stress and DNA damage, despite rapid induction of stress markers, such as XBP-1(s), CHOP, and PUMA. Gene expression profiling revealed a general suppression of pro-apoptotic machinery, such as Apaf-1 and caspase 3, and sustained levels of pro-survival factors, such as cIAP-1, cIAP-2, and XIAP, in rat islets. Furthermore, we observed sustained induction of autophagy following chronic ER stress and found that inhibition of autophagy rendered islet β-cells highly vulnerable to ER stress-induced cell death. We propose that islet β-cells dampen the apoptotic response to delay the onset of cell death, providing a temporal window in which autophagy can be activated to limit cellular damage and promote survival.

  18. Altered liver acini induced in diabetic rats by portal vein islet isografts resemble preneoplastic hepatic foci in their enzymic pattern.

    PubMed Central

    Dombrowski, F.; Filsinger, E.; Bannasch, P.; Pfeifer, U.

    1996-01-01

    As demonstrated previously, liver acini draining the blood from intraportally transplanted pancreatic islets in streptozotocin-diabetic rats are altered in various respects. The hepatocytes in these acini store glycogen and/or fat, and they show an increase in proliferation as well as in apoptotic activity. Thus, they are phenotypically similar to carcinogen-induced preneoplastic liver foci (glycogen-storing foci and sometimes also mixed cell foci). By means of catalytic enzyme histochemistry or immunohistochemistry, we investigated the activity of key enzymes of alternative pathways of carbohydrate metabolism and some additional marker enzymes (well known from studies on preneoplastic hepatic foci) in the altered liver acini surrounding the islet isografts. In addition, the expression of glucose transporter proteins 1 and 2 (GLUT-1 and GLUT-2) were investigated immunohistochemically. The activities of hexokinase, pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase, and glucose-6-phosphate dehydrogenase were increased, whereas the activities of glycogen phosphorylase, adenylate cyclase, glucose-6-phosphatase, and membrane-bound adenosine triphosphatase were decreased in the altered liver acini. The expression of GLUT-2 was also decreased. GLUT-1 and glutathione S-transferase placental form were not expressed, and the activities of glycogen synthase and gamma-glutamyl-transferase remained unchanged. All changes of the enzyme activities were in line with the well known effects of insulin and resembled alterations characteristic of preneoplastic liver foci observed in different models of hepatocarcinogenesis. It remains to be clarified in long-term experiments whether or not these foci represent preneoplastic lesions and may proceed to neoplasia. Images Figure 1 Figure 2 PMID:8644865

  19. Anaplerotic input is sufficient to induce time-dependent potentiation of insulin release in rat pancreatic islets.

    PubMed

    Gunawardana, Subhadra C; Liu, Yi-Jia; Macdonald, Michael J; Straub, Susanne G; Sharp, Geoffrey W G

    2004-11-01

    Nutrients that induce biphasic insulin release, such as glucose and leucine, provide acetyl-CoA and anaplerotic input in the beta-cell. The first phase of release requires increased ATP production leading to increased intracellular Ca(2+) concentration ([Ca(2+)](i)). The second phase requires increased [Ca(2+)](i) and anaplerosis. There is strong evidence to indicate that the second phase is due to augmentation of Ca(2+)-stimulated release via the K(ATP) channel-independent pathway. To test whether the phenomenon of time-dependent potentiation (TDP) has similar properties to the ATP-sensitive K(+) channel-independent pathway, we monitored the ability of different agents that provide acetyl-CoA and anaplerotic input or both of these inputs to induce TDP. The results show that anaplerotic input is sufficient to induce TDP. Interestingly, among the agents tested, the nonsecretagogue glutamine, the nonhydrolyzable analog of leucine aminobicyclo[2.2.1]heptane-2-carboxylic acid, and succinic acid methyl ester all induced TDP, and all significantly increased alpha-ketoglutarate levels in the islets. In conclusion, anaplerosis that enhances the supply and utilization of alpha-ketoglutarate in the tricarboxylic acid cycle appears to play an essential role in the generation of TDP.

  20. Hyposmolar medium and ethanol in isosmotic solution induce the release of thyrotropin-releasing hormone (TRH) by isolated rat pancreatic islets.

    PubMed

    Benický, J; Greer, M A; Strbák, V

    1997-01-01

    Cell swelling induced by hypotonic medium or small isotonic permeant molecules results in an immediate secretory response in various types of cells. We have expanded exploration of this phenomenon by examining the effect of either isotonic ethanol or hyposmotic medium on the release of TRH by freshly isolated islets of Langerhans in static incubation and perifusion. Ethanol (40, 80 or 160 mM in isotonic solution) dose-dependently evoked the release of TRH by statically incubated islets. The dynamics of TRH release induced by 80 mM isotonic ethanol or 30% hypotonic medium were similar to those induced by 50 mM KCl, with the highest secretion rate during the first 5 min of incubation irrespective of the duration of stimulation. Ca2+ depletion of the incubation medium abolished the response to 50 mM KCl but did not diminish the response to 80 mM isotonic ethanol. We conclude that osmotic stimuli known to induce cell swelling also induce release of TRH by isolated pancreatic islets.

  1. Preservation of pancreatic islets in cold UW solution before transplantation.

    PubMed

    Ishii, Show; Saito, Takuro; Ise, Kazuya; Yamashita, Michitoshi; Sato, Yoshihiro; Saito, Takaharu; Tsukada, Manabu; Oshibe, Ikuro; Kenjo, Akira; Kimura, Takashi; Anazawa, Takayuki; Suzuki, Shigeya; Gotoh, Mitsukazu

    2012-01-01

    Culture of islets prior to transplantation needs to be revisited for maintaining functional islet capacity. This study was conducted to compare cold UW (University of Wisconsin) preservation with conventional culture based on insulin secretory capacity in vitro and in vivo. Islets isolated from Wistar rats were either cultured for 24 h at 37°C in RPMI1640 medium or DMEM containing various concentrations of glucose or preserved for the same period in UW solution or in DMEM solution at 4°C. The islet yield in UW group, but not in other groups, was maintained as comparable with that of fresh islets. Insulin secretory capacity in response to glucose was maintained only in the islets of UW group, but not in other groups. SCID mice given 300 IEQ islets of UW group showed gradual restoration of normoglycemia as found in the mice given freshly isolated islets. Meanwhile, those mice given cultured islets for 24 h at 37°C in RPMI1640 medium showed rapid decrease of blood glucose levels on day 1 followed by relatively elevated levels on day 2, suggesting unstable insulin secretory capacity of islets.   Morphological staining with anti-HMGB1 (high mobility group B1) antibody revealed central damage of islets in all culture groups regardless of glucose concentration and in islets of cold DMEM group, whereas those in the UW group were quite intact. These results suggest that cold preservation in UW solution is simple and beneficial in protecting islets morphologically and functionally before transplantation.

  2. Effect of polyethylene glycol grafted onto islet capsules on prevention of splenocyte and cytokine attacks.

    PubMed

    Lee, Dong Yun; Nam, Jong Hee; Byun, Youngro

    2004-01-01

    In the graft rejection of transplanted islets, the host's immune cells recognize the islets as antigens, which then stimulate the immune cells to begin the cytokine secretion and also the proliferation of immune cells. To prevent the recognition of islets by the immune cells, we grafted biocompatible polyethylene glycol (PEG) onto the collagen capsule of islets without incurring any changes in the morphology and function of islets. To evaluate the efficiency of PEG grafting, PEG-grafted islets were cultured with splenocytes consisting mainly of lymphocytes and macrophages. A splenocyte proliferation assessment using a BrdU incorporation assay showed that the PEG-grafted islets did not stimulate the splenocytes. In addition, the viability and microorganisms in islet cells of co-cultured PEG-grafted islets were not altered. However, in the co-culture of free islets (control) splenocytes were stimulated; they mainly secreted TNF-alpha and strongly affected the viability and structure of free islets. Furthermore, when islets were treated with the rat recombinant TNF-alpha for 7 days, the viabilities of PEG-grafted and free islets were significantly damaged, although the viability of PEG-grafted islets was higher than that of free islets by nearly three times. These results demonstrate that PEG grafted on the surface of islets could prevent the recognition of islets by splenocytes, but could not completely protect islets from cytokines.

  3. Mechanisms of bleomycin-induced lung damage.

    PubMed

    Hay, J; Shahzeidi, S; Laurent, G

    1991-01-01

    Bleomycins are a family of compounds produced by Streptomyces verticillis. They have potent tumour killing properties which have given them an important place in cancer chemotherapy. They cause little marrow suppression, but pulmonary toxicity is a major adverse effect. The mechanisms of cell toxicity are well described based on in vitro experiments on DNA. The bleomycin molecule has two main structural components: a bithiazole component which partially intercalates into the DNA helix, parting the strands, as well as pyrimidine and imidazole structures, which bind iron and oxygen forming an activated complex capable of releasing damaging oxidants in close proximity to the polynucleotide chains of DNA. This may lead to chain scission or structural modifications leading to release of free bases or their propenal derivatives. The mechanisms are well described based on in vitro experiments on DNA, but how they relate to intact cells in whole animals is more tenuous. Bleomycin is able to cause cell damage independent from its effect on DNA by induction lipid peroxidation. This may be particularly important in the lung and in part account for its ability to cause alveolar cell damage and subsequent pulmonary inflammation. The lung injury seen following bleomycin comprises an interstitial oedema with an influx of inflammatory and immune cells. This may lead to the development of pulmonary fibrosis, characterized by enhanced production and deposition of collagen and other matrix components. Several polypeptide mediators capable of stimulating fibroblasts replication or excessive collagen deposition have been implicated in this, but the precise role of these in bleomycin-induced fibrosis is yet to be demonstrated. Current therapy for bleomycin-induced lung damage is inadequate, with corticosteroids most often used. Given the mechanism of action described above, antioxidants and iron chelators might be beneficial. Although, studies to date are equivocal and there is

  4. Laser-Induced Damage of Calcium Fluoride

    SciTech Connect

    Espana, A.; Joly, A.G.; Hess, W.P.; Dickinson, J.T.

    2004-01-01

    As advances continue to be made in laser technology there is an increasing demand for materials that have high thresholds for laser-induced damage. Laser damage occurs when light is absorbed, creating defects in the crystal lattice. These defects can lead to the emission of atoms, ions and molecules from the sample. One specific field where laser damage is of serious concern is semiconductor lithography, which is beginning to use light at a wavelength of 157 nm. CaF2 is a candidate material for use in this new generation of lithography. In order to prevent unnecessary damage of optical components, it is necessary to understand the mechanisms for laser damage and the factors that serve to enhance it. In this research, we study various aspects of laser interactions with CaF2, including impurity absorbance and various forms of damage caused by incident laser light. Ultraviolet (UV) laser light at 266 nm with both femtosecond (fs) and nanosecond (ns) pulse widths is used to induce ion and neutral particle emission from cleaved samples of CaF2. The resulting mass spectra show significant differences suggesting that different mechanisms for desorption occur following excitation using the different pulse durations. Following irradiation by ns pulses at 266 nm, multiple single-photon absorption from defect states is likely responsible for ion emission whereas the fs case is driven by a multi-photon absorption process. This idea is further supported by the measurements made of the transmission and reflection of fs laser pulses at 266 nm, the results of which reveal a non-linear absorption process in effect at high incident intensities. In addition, the kinetic energy profiles of desorbed Ca and K contaminant atoms are different indicating that a different mechanism is responsible for their emission as well. Overall, these results show that purity plays a key role in the desorption of atoms from CaF2 when using ns pulses. On the other hand, once the irradiance reaches high

  5. [Isogenic islet transplantation on the rat liver (method for isolation and purification of the Langerhans islets)].

    PubMed

    Chaib, E; Papalois, A; Brons, I G; Calne, R Y

    2000-01-01

    The major indication for pancreas or islet transplantation is diabetes mellitus type I. This process has to supply the insulin necessity keeping glucose under control. We have studied isogenic islet transplantation on the rat (WAG-RT1u) liver. The method of isolation and purification of the islets obtained 2.834 +/- 551.64 islets with purity of 83 +/- 2.45%. Diabetes was induced by streptozotocin and seric glucose prior transplantation was 35 mmol/L. The islet transplantation of 2.834 +/- 551.64 islets in the rat liver has normalized glucose test from 9.62 +/- 2.65 mmol/L 10 days after transplantation to 7.43 +/- 0.27 mmol/L later in the follow-up (P < 0.05). The median survival time of the islets was 73 days. In conclusion both the method of isolation and purification of the islets and islet transplantation was effective in the control of the diabetes induced by streptozotocin with median survival time of both islet and rat more than 73 days when rats were sacrified.

  6. Advanced Glycation End-Products Induce Apoptosis in Pancreatic Islet Endothelial Cells via NF-κB-Activated Cyclooxygenase-2/Prostaglandin E2 Up-Regulation

    PubMed Central

    Lan, Kuo-Cheng; Chiu, Chen-Yuan; Kao, Chia-Wei; Huang, Kuo-How; Wang, Ching-Chia; Huang, Kuo-Tong; Tsai, Keh-Sung

    2015-01-01

    Microvascular complications eventually affect nearly all patients with diabetes. Advanced glycation end-products (AGEs) resulting from hyperglycemia are a complex and heterogeneous group of compounds that accumulate in the plasma and tissues in diabetic patients. They are responsible for both endothelial dysfunction and diabetic vasculopathy. The aim of this study was to investigate the cytotoxicity of AGEs on pancreatic islet microvascular endothelial cells. The mechanism underlying the apoptotic effect of AGEs in pancreatic islet endothelial cell line MS1 was explored. The results showed that AGEs significantly decreased MS1 cell viability and induced MS1 cell apoptosis in a dose-dependent manner. AGEs dose-dependently increased the expressions of cleaved caspase-3, and cleaved poly (ADP-ribose) polymerase in MS1 cells. Treatment of MS1 cells with AGEs also resulted in increased nuclear factor (NF)-κB-p65 phosphorylation and cyclooxygenase (COX)-2 expression. However, AGEs did not affect the expressions of endoplasmic reticulum (ER) stress-related molecules in MS1 cells. Pretreatment with NS398 (a COX-2 inhibitor) to inhibit prostaglandin E2 (PGE2) production reversed the induction of cleaved caspase-3, cleaved PARP, and MS1 cell viability. Moreover, AGEs significantly increased the receptor for AGEs (RAGE) protein expression in MS1 cells, which could be reversed by RAGE neutralizing antibody. RAGE Neutralizing antibody could also reverse the induction of cleaved caspase-3 and cleaved PARP and decreased cell viability induced by AGEs. These results implicate the involvement of NF-κB-activated COX-2/PGE2 up-regulation in AGEs/RAGE-induced islet endothelial cell apoptosis and cytotoxicity. These findings may provide insight into the pathological processes within the pancreatic islet microvasculature induced by AGEs accumulation. PMID:25898207

  7. High-Fat Diet-Induced Insulin Resistance Does Not Increase Plasma Anandamide Levels or Potentiate Anandamide Insulinotropic Effect in Isolated Canine Islets

    PubMed Central

    Woolcott, Orison O.; Richey, Joyce M.; Kabir, Morvarid; Chow, Robert H.; Iyer, Malini S.; Kirkman, Erlinda L.; Stefanovski, Darko; Lottati, Maya; Kim, Stella P.; Harrison, L. Nicole; Ionut, Viorica; Zheng, Dan; Hsu, Isabel R.; Catalano, Karyn J.; Chiu, Jenny D.; Bradshaw, Heather; Wu, Qiang; Bergman, Richard N.

    2015-01-01

    Background Obesity has been associated with elevated plasma anandamide levels. In addition, anandamide has been shown to stimulate insulin secretion in vitro, suggesting that anandamide might be linked to hyperinsulinemia. Objective To determine whether high-fat diet-induced insulin resistance increases anandamide levels and potentiates the insulinotropic effect of anandamide in isolated pancreatic islets. Design and Methods Dogs were fed a high-fat diet (n = 9) for 22 weeks. Abdominal fat depot was quantified by MRI. Insulin sensitivity was assessed by the euglycemic-hyperinsulinemic clamp. Fasting plasma endocannabinoid levels were analyzed by liquid chromatography-mass spectrometry. All metabolic assessments were performed before and after fat diet regimen. At the end of the study, pancreatic islets were isolated prior to euthanasia to test the in vitro effect of anandamide on islet hormones. mRNA expression of cannabinoid receptors was determined in intact islets. The findings in vitro were compared with those from animals fed a control diet (n = 7). Results Prolonged fat feeding increased abdominal fat content by 81.3±21.6% (mean±S.E.M, P<0.01). In vivo insulin sensitivity decreased by 31.3±12.1% (P<0.05), concomitant with a decrease in plasma 2-arachidonoyl glycerol (from 39.1±5.2 to 15.7±2.0 nmol/L) but not anandamide, oleoyl ethanolamide, linoleoyl ethanolamide, or palmitoyl ethanolamide. In control-diet animals (body weight: 28.8±1.0 kg), islets incubated with anandamide had a higher basal and glucose-stimulated insulin secretion as compared with no treatment. Islets from fat-fed animals (34.5±1.3 kg; P<0.05 versus control) did not exhibit further potentiation of anandamide-induced insulin secretion as compared with control-diet animals. Glucagon but not somatostatin secretion in vitro was also increased in response to anandamide, but there was no difference between groups (P = 0.705). No differences in gene expression of CB1R or CB2R between groups

  8. High-fat diet-induced insulin resistance does not increase plasma anandamide levels or potentiate anandamide insulinotropic effect in isolated canine islets.

    PubMed

    Woolcott, Orison O; Richey, Joyce M; Kabir, Morvarid; Chow, Robert H; Iyer, Malini S; Kirkman, Erlinda L; Stefanovski, Darko; Lottati, Maya; Kim, Stella P; Harrison, L Nicole; Ionut, Viorica; Zheng, Dan; Hsu, Isabel R; Catalano, Karyn J; Chiu, Jenny D; Bradshaw, Heather; Wu, Qiang; Kolka, Cathryn M; Bergman, Richard N

    2015-01-01

    Obesity has been associated with elevated plasma anandamide levels. In addition, anandamide has been shown to stimulate insulin secretion in vitro, suggesting that anandamide might be linked to hyperinsulinemia. To determine whether high-fat diet-induced insulin resistance increases anandamide levels and potentiates the insulinotropic effect of anandamide in isolated pancreatic islets. Dogs were fed a high-fat diet (n = 9) for 22 weeks. Abdominal fat depot was quantified by MRI. Insulin sensitivity was assessed by the euglycemic-hyperinsulinemic clamp. Fasting plasma endocannabinoid levels were analyzed by liquid chromatography-mass spectrometry. All metabolic assessments were performed before and after fat diet regimen. At the end of the study, pancreatic islets were isolated prior to euthanasia to test the in vitro effect of anandamide on islet hormones. mRNA expression of cannabinoid receptors was determined in intact islets. The findings in vitro were compared with those from animals fed a control diet (n = 7). Prolonged fat feeding increased abdominal fat content by 81.3±21.6% (mean±S.E.M, P<0.01). In vivo insulin sensitivity decreased by 31.3±12.1% (P<0.05), concomitant with a decrease in plasma 2-arachidonoyl glycerol (from 39.1±5.2 to 15.7±2.0 nmol/L) but not anandamide, oleoyl ethanolamide, linoleoyl ethanolamide, or palmitoyl ethanolamide. In control-diet animals (body weight: 28.8±1.0 kg), islets incubated with anandamide had a higher basal and glucose-stimulated insulin secretion as compared with no treatment. Islets from fat-fed animals (34.5±1.3 kg; P<0.05 versus control) did not exhibit further potentiation of anandamide-induced insulin secretion as compared with control-diet animals. Glucagon but not somatostatin secretion in vitro was also increased in response to anandamide, but there was no difference between groups (P = 0.705). No differences in gene expression of CB1R or CB2R between groups were found. In canines, high-fat diet-induced

  9. Magnetic resonance-defined periportal steatosis following intraportal islet transplantation: a functional footprint of islet graft survival?

    PubMed

    Markmann, James F; Rosen, Mark; Siegelman, Evan S; Soulen, Michael C; Deng, Shaoping; Barker, Clyde F; Naji, Ali

    2003-07-01

    There is growing interest in more widespread application of isolated islet transplantation for the treatment of type 1 diabetes; however, the sequelae of long-term islet residence within the liver are unknown. We report herein a consequence of intraportal islet transplantation, specifically the development of periportal hepatic steatosis apparently induced by the local secretion of insulin within the liver.

  10. Fibroblast Growth Factor 21 (FGF21) Protects against High Fat Diet Induced Inflammation and Islet Hyperplasia in Pancreas

    PubMed Central

    Singhal, Garima; Fisher, ffolliott Martin; Chee, Melissa J.; Tan, Tze Guan; El Ouaamari, Abdelfattah; Adams, Andrew C.; Najarian, Robert; Kulkarni, Rohit N.; Benoist, Christophe; Flier, Jeffrey S.; Maratos-Flier, Eleftheria

    2016-01-01

    Fibroblast growth factor 21 (FGF21) is an important endocrine metabolic regulator expressed in multiple tissues including liver and adipose tissue. Although highest levels of expression are in pancreas, little is known about the function of FGF21 in this tissue. In order to understand the physiology of FGF21 in the pancreas, we analyzed its expression and regulation in both acinar and islet tissues. We found that acinar tissue express 20-fold higher levels than that observed in islets. We also observed that pancreatic FGF21 is nutritionally regulated; a marked reduction in FGF21 expression was noted with fasting while obesity is associated with 3–4 fold higher expression. Acinar and islet cells are targets of FGF21, which when systemically administered, leads to phosphorylation of the downstream target ERK 1/2 in about half of acinar cells and a small subset of islet cells. Chronic, systemic FGF21 infusion down-regulates its own expression in the pancreas. Mice lacking FGF21 develop significant islet hyperplasia and periductal lymphocytic inflammation when fed with a high fat obesogenic diet. Inflammatory infiltrates consist of TCRb+ Thy1+ T lymphocytes with increased levels of Foxp3+ regulatory T cells. Increased levels of inflammatory cells were coupled with elevated expression of cytokines such as TNFα, IFNγ and IL1β. We conclude that FGF21 acts to limit islet hyperplasia and may also prevent pancreatic inflammation. PMID:26872145

  11. Fibroblast Growth Factor 21 (FGF21) Protects against High Fat Diet Induced Inflammation and Islet Hyperplasia in Pancreas.

    PubMed

    Singhal, Garima; Fisher, Ffolliott Martin; Chee, Melissa J; Tan, Tze Guan; El Ouaamari, Abdelfattah; Adams, Andrew C; Najarian, Robert; Kulkarni, Rohit N; Benoist, Christophe; Flier, Jeffrey S; Maratos-Flier, Eleftheria

    2016-01-01

    Fibroblast growth factor 21 (FGF21) is an important endocrine metabolic regulator expressed in multiple tissues including liver and adipose tissue. Although highest levels of expression are in pancreas, little is known about the function of FGF21 in this tissue. In order to understand the physiology of FGF21 in the pancreas, we analyzed its expression and regulation in both acinar and islet tissues. We found that acinar tissue express 20-fold higher levels than that observed in islets. We also observed that pancreatic FGF21 is nutritionally regulated; a marked reduction in FGF21 expression was noted with fasting while obesity is associated with 3-4 fold higher expression. Acinar and islet cells are targets of FGF21, which when systemically administered, leads to phosphorylation of the downstream target ERK 1/2 in about half of acinar cells and a small subset of islet cells. Chronic, systemic FGF21 infusion down-regulates its own expression in the pancreas. Mice lacking FGF21 develop significant islet hyperplasia and periductal lymphocytic inflammation when fed with a high fat obesogenic diet. Inflammatory infiltrates consist of TCRb+ Thy1+ T lymphocytes with increased levels of Foxp3+ regulatory T cells. Increased levels of inflammatory cells were coupled with elevated expression of cytokines such as TNFα, IFNγ and IL1β. We conclude that FGF21 acts to limit islet hyperplasia and may also prevent pancreatic inflammation.

  12. Islet cell hormonal responses to hypoglycemia after human islet transplantation for type 1 diabetes.

    PubMed

    Rickels, Michael R; Schutta, Mark H; Mueller, Rebecca; Markmann, James F; Barker, Clyde F; Naji, Ali; Teff, Karen L

    2005-11-01

    Islet transplantation can eliminate severe hypoglycemic episodes in patients with type 1 diabetes; however, whether intrahepatic islets respond appropriately to hypoglycemia after transplantation has not been fully studied. We evaluated six islet transplant recipients, six type 1 diabetic subjects, and seven nondiabetic control subjects using a stepped hyperinsulinemic-hypoglycemic clamp. Also, three islet transplant recipients and the seven control subjects underwent a paired hyperinsulinemic-euglycemic clamp. In response to hypoglycemia, C-peptide was similarly suppressed in islet transplant recipients and control subjects and was not detectable in type 1 diabetic subjects. Glucagon was significantly more suppressed in type 1 diabetic subjects than in islet transplant recipients (P < 0.01), although the glucagon in islet transplant recipients failed to activate as in the control subjects (P < 0.01). Pancreatic polypeptide failed to activate in both type 1 diabetic subjects and islet transplant recipients compared with control subjects (P < 0.01). In islet transplant recipients, glucagon was suppressed normally by hyperinsulinemia during the euglycemic clamp and was significantly greater during the paired hypoglycemic clamp (P < 0.01). These results suggest that after islet transplantation and in response to insulin-induced hypoglycemia, endogenous insulin secretion is appropriately suppressed and glucagon secretion may be partially restored.

  13. St. John's wort extract and hyperforin protect rat and human pancreatic islets against cytokine toxicity.

    PubMed

    Novelli, Michela; Beffy, Pascale; Menegazzi, Marta; De Tata, Vincenzo; Martino, Luisa; Sgarbossa, Anna; Porozov, Svetlana; Pippa, Anna; Masini, Matilde; Marchetti, Piero; Masiello, Pellegrino

    2014-02-01

    The extract of Hypericum perforatum (St. John's wort, SJW) and its component hyperforin (HPF) were previously shown to inhibit cytokine-induced activation of signal transducer and activator of transcription-1 and nuclear factor κB and prevent apoptosis in a cultured β-cell line. Objective of this study was to assess the protection exerted by SJW and HPF on isolated rat and human islets exposed to cytokines in vitro. Functional, ultrastructural, biomolecular and cell death evaluation studies were performed. In both rat and human islets, SJW and HPF counteracted cytokine-induced functional impairment and down-regulated mRNA expression of pro-inflammatory target genes, such as iNOS, CXCL9, CXCL10, COX2. Cytokine-induced NO production from cultured islets, evaluated by nitrites measurement in the medium, was significantly reduced in the presence of the vegetal compounds. Noteworthy, the increase in apoptosis and necrosis following 48-h exposure to cytokines was fully prevented by SJW and partially by HPF. Ultrastructural morphometric analysis in human islets exposed to cytokines for 20 h showed that SJW or HPF avoided early β-cell damage (e.g., mitochondrial alterations and loss of insulin granules). In conclusion, SJW compounds protect rat and human islets against cytokine effects by counteracting key mechanisms of cytokine-mediated β-cell injury and represent promising pharmacological tools for prevention or limitation of β-cell dysfunction and loss in type 1 diabetes.

  14. Structure-function studies of PANDER, an islet specific cytokine inducing cell death of insulin-secreting beta cells.

    PubMed

    Yang, Jichun; Gao, Zhiyong; Robert, Claudia E; Burkhardt, Brant R; Gaweska, Helena; Wagner, Amary; Wu, Jianmei; Greene, Scott R; Young, Robert A; Wolf, Bryan A

    2005-08-30

    PANDER (pancreatic derived factor, FAM3B) is a novel cytokine, present in insulin secretory granules, that induces apoptosis of alpha and beta cells of mouse, rat, and human islets in a dose- and time-dependent manner, and may be implicated in diabetes. PANDER has the predicted secondary structure of 4 alpha-helical bundles with an up-up-down-down topology, and two disulfide bonds. Eleven mutated PANDERs were constructed and expressed in beta-TC3 cells to identify the essential region of PANDER involved in beta-cell death. Beta-cell function was assessed by assays of cell viability and insulin secretion. Based on quantitative real-time RT-PCR all mutant PANDERs had similar mRNA expression levels in beta-TC3 cells. Immunoblotting showed that ten of eleven mutant PANDER proteins were synthesized and detected in beta-TC3 cells. A mutant PANDER with no signal peptide, however, was not expressed. Truncation of helix D alone caused a 40-50% decrease in PANDER's activity, while truncation of both helices C and D resulted in a 75% loss of activity. In contrast, truncation of the N-terminus of PANDER (helix A, the loop between helices A and B, and the first two cysteines) had no effect on PANDER-induced beta-cell death. The third and fourth cysteines of PANDER, C91 and C229, were shown to form one disulfide bond and be functionally important. Finally, the region between Cys91 and Phe152 constitutes the active part of PANDER, based on the demonstration that mutants with truncation of helix B or C caused decreased beta-cell death and did not inhibit insulin secretion, as compared to wild-type PANDER. Hence, helices B and C and the second disulfide bond of PANDER are essential for PANDER-induced beta-cell death.

  15. Insulin hypersecretion in islets from diet-induced hyperinsulinemic obese female mice is associated with several functional adaptations in individual β-cells.

    PubMed

    Gonzalez, Alejandro; Merino, Beatriz; Marroquí, Laura; Ñeco, Patricia; Alonso-Magdalena, Paloma; Caballero-Garrido, Ernesto; Vieira, Elaine; Soriano, Sergi; Gomis, Ramon; Nadal, Angel; Quesada, Ivan

    2013-10-01

    Insulin resistance and hyperinsulinemia are generally associated with obesity. Obese nondiabetic individuals develop a compensatory β-cell response to adjust insulin levels to the increased demand, maintaining euglycemia. Although several studies indicate that this compensation relies on structural changes, the existence of β-cell functional adaptations is incompletely understood. Here, we fed female mice with a high-fat diet (HFD) for 12 weeks. These animals became obese, hyperinsulinemic, insulin-resistant, and mildly glucose-intolerant while fed, and fasting glycemia was comparable in HFD and control mice. Islets from HFD animals exhibited increased β-cell mass and hypertrophy. Additionally, they had enhanced insulin gene expression and content and augmented glucose-induced insulin secretion. Electrophysiological examination of β-cells from both groups showed no differences in KATP channel open probability and conductance. However, action potentials elicited by glucose had larger amplitude in obese mice. Glucose-induced Ca²⁺ signals in intact islets, in isolated β-cells, and individual β-cells within islets were also increased in HFD mice. Additionally, a higher proportion of glucose-responsive cells was present in obese mice. In contrast, whole-cell Ca²⁺ current densities were similar in both groups. Capacitance measurements showed that depolarization-evoked exocytosis was enhanced in HFD β-cells compared with controls. Although this augment was not significant when capacitance increases of the whole β-cell population were normalized to cell size, the exocytotic output varied significantly when β-cells were distributed by size ranges. All these findings indicate that β-cell functional adaptations are present in the islet compensatory response to obesity.

  16. Compensatory hyperinsulinemia in high-fat diet-induced obese mice is associated with enhanced insulin translation in islets

    SciTech Connect

    Kanno, Ayumi; Asahara, Shun-ichiro; Masuda, Katsuhisa; Matsuda, Tomokazu; Kimura-Koyanagi, Maki; Seino, Susumu; Ogawa, Wataru; Kido, Yoshiaki

    2015-03-13

    A high-fat diet (HF) is associated with obesity, insulin resistance, and hyperglycemia. Animal studies have shown compensatory mechanisms in pancreatic β-cells after high fat load, such as increased pancreatic β-cell mass, enhanced insulin secretion, and exocytosis. However, the effects of high fat intake on insulin synthesis are obscure. Here, we investigated whether insulin synthesis was altered in correlation with an HF diet, for the purpose of obtaining further understanding of the compensatory mechanisms in pancreatic β-cells. Mice fed an HF diet are obese, insulin resistant, hyperinsulinemic, and glucose intolerant. In islets of mice fed an HF diet, more storage of insulin was identified. We analyzed insulin translation in mouse islets, as well as in INS-1 cells, using non-radioisotope chemicals. We found that insulin translational levels were significantly increased in islets of mice fed an HF diet to meet systemic demand, without altering its transcriptional levels. Our data showed that not only increased pancreatic β-cell mass and insulin secretion but also elevated insulin translation is the major compensatory mechanism of pancreatic β-cells. - Highlights: • More stored insulin was recognized in islets of mice fed a high-fat diet. • Insulin translation was not enhanced by fatty acids, but by insulin demand. • Insulin transcription was not altered in islets of mice fed a high-fat diet. • Insulin translation was markedly enhanced in islets of mice fed a high-fat diet. • Non-radioisotope chemicals were used to measure insulin translation in mouse islets.

  17. Preventing hypoxia-induced cell death in beta cells and islets via hydrolytically activated, oxygen-generating biomaterials

    PubMed Central

    Pedraza, Eileen; Coronel, Maria M.; Fraker, Christopher A.; Ricordi, Camillo; Stabler, Cherie L.

    2012-01-01

    A major hindrance in engineering tissues containing highly metabolically active cells is the insufficient oxygenation of these implants, which results in dying or dysfunctional cells in portions of the graft. The development of methods to increase oxygen availability within tissue-engineered implants, particularly during the early engraftment period, would serve to allay hypoxia-induced cell death. Herein, we designed and developed a hydrolytically activated oxygen-generating biomaterial in the form of polydimethylsiloxane (PDMS)-encapsulated solid calcium peroxide, PDMS-CaO2. Encapsulation of solid peroxide within hydrophobic PDMS resulted in sustained oxygen generation, whereby a single disk generated oxygen for more than 6 wk at an average rate of 0.026 mM per day. The ability of this oxygen-generating material to support cell survival was evaluated using a β cell line and pancreatic rat islets. The presence of a single PDMS-CaO2 disk eliminated hypoxia-induced cell dysfunction and death for both cell types, resulting in metabolic function and glucose-dependent insulin secretion comparable to that in normoxic controls. A single PDMS-CaO2 disk also sustained enhanced β cell proliferation for more than 3 wk under hypoxic culture conditions. Incorporation of these materials within 3D constructs illustrated the benefits of these materials to prevent the development of detrimental oxygen gradients within large implants. Mathematical simulations permitted accurate prediction of oxygen gradients within 3D constructs and highlighted conditions under which supplementation of oxygen tension would serve to benefit cellular viability. Given the generality of this platform, the translation of these materials to other cell-based implants, as well as ischemic tissues in general, is envisioned. PMID:22371586

  18. Correlation of polishing-induced shallow subsurface damages with laser-induced gray haze damages in fused silica optics

    NASA Astrophysics Data System (ADS)

    He, Xiang; Zhao, Heng; Wang, Gang; Zhou, Peifan; Ma, Ping

    2016-08-01

    Laser-induced damage in fused silica optics greatly restricts the performances of laser facilities. Gray haze damage, which is always initiated on ceria polished optics, is one of the most important damage morphologies in fused silica optics. In this paper, the laser-induced gray haze damages of four fused silica samples polished with CeO2, Al2O3, ZrO2, and colloidal silica slurries are investigated. Four samples all present gray haze damages with much different damage densities. Then, the polishing-induced contaminant and subsurface damages in four samples are analyzed. The results reveal that the gray haze damages could be initiated on the samples without Ce contaminant and are inclined to show a tight correlation with the shallow subsurface damages.

  19. Transplantation of allogeneic islets of Langerhans in the rat liver: effects of macrophage depletion on graft survival and microenvironment activation.

    PubMed

    Bottino, R; Fernandez, L A; Ricordi, C; Lehmann, R; Tsan, M F; Oliver, R; Inverardi, L

    1998-03-01

    Early impairment of islet function and graft loss limit the success of allogeneic islet transplantation. Nonspecific inflammatory events occurring at the transplant site immediately after grafting, involving the production of cytokines and free radicals and sinusoidal endothelial cell (SEC) activation, may contribute to islet cell damage. To evaluate whether Kupffer cell inactivation would result in prolonged allograft survival in a model system of intrahepatic islet transplantation in rats, we systemically administered either gadolinium chloride (GdCl3) or dichloromethylene diphosphonate (Cl2MDP) to assess the effects of macrophage inactivation on rejection and on the release of proinflammatory molecules, as well as to assess the functional profile of SEC. The results obtained were compared with those observed in untreated, sham-injected animals and in rats receiving intraportal infusions of microbeads. Transient macrophage inhibition, particularly in hepatic Kupffer cells, is associated with significant prolongation of graft survival after intraportal islet allotransplantation (ITx) in rats: 7.2 days in the control group versus 11.9 days in the GdCl3 group (P < 0.01) and 15.6 days in the Cl2MDP group (P < 0.0006), respectively. Although systemic release of inflammatory mediators was observed only when islet transplantations were performed and it could be inhibited by macrophage-targeting treatments, perturbation of the functional profile of endothelial cells was also observed when microembolization was induced by the use of microbeads and could not be prevented by macrophage inhibition. These experiments provide evidence to support the concept that macrophages play a key role in early inflammatory events known to adversely affect islet engraftment and suggest that manipulation of nonspecific immune activation by inhibition of macrophage function may facilitate hepatic engraftment of islet allografts. The mechanisms mediating this effect are likely to include

  20. Suppression of ROS Production by Exendin-4 in PSC Attenuates the High Glucose-Induced Islet Fibrosis

    PubMed Central

    Kim, Ji-Won; Park, Shin-Young; You, Young-Hye; Ham, Dong-Sik; Lee, Seung-Hwan; Yang, Hae Kyung; Jeong, In-Kyung; Ko, Seung-Hyun

    2016-01-01

    Pancreatic stellate cells (PSCs) play a major role to fibrotic islet destruction observed in diabetic patients and animal model of diabetes. Exendin-4 (Ex-4) is a potent insulinotropic agent and has been approved for the treatment of type 2 diabetes. However, there have been no reports demonstrating the effects of Ex-4 on pancreatic islet fibrosis. In this study, Ex-4 treatment clearly attenuated fibrotic islet destruction and improved glucose tolerance and islet survival. GLP-1 receptor expression was upregulated during activation and proliferation of PSCs by hyperglycemia. The activation of PKA pathway by Ex-4 plays a role in ROS production and angiotensin II (Ang II) production. Exposure to high glucose stimulated ERK activation and Ang II-TGF- β1 production in PSCs. Interestingly, Ex-4 significantly reduced Ang II and TGF-β1 production by inhibition of ROS production but not ERK phosphorylation. Ex-4 may be useful not only as an anti-diabetic agent but also as an anti-fibrotic agent in type 2 diabetes due to its ability to inhibit PSC activation and proliferation and improve islet fibrosis in OLETF rats. PMID:27977690

  1. Factors controlling pancreatic islet neogenesis.

    PubMed Central

    Vinik, A.; Pittenger, G.; Rafaeloff, R.; Rosenberg, L.

    1992-01-01

    We have established a model in which cellophane wrapping induces reiteration of the normal ontogeny of beta-cell differentiation from ductal tissue. The secretion of insulin is physiologic and coordinated to the needs of the animal. Streptozotocin-induced diabetes in hamsters can be "cured" at least half the time. There appears to be activation of growth factor(s) within the pancreas, acting in an autocrine, paracrine, or juxtacrine manner to induce ductal cell proliferation and differentiation into functioning beta cells. Given the results of our studies to date, it does not seem premature to envisage new approaches to the treatment of diabetes mellitus. Identification of the factor(s) regulating islet-cell proliferation and differentiation in our model may permit islets to be grown in culture. This concept could be extended to induce endocrine cell differentiation in vitro as well. Furthermore, islet-cell growth factors could be used to provide "trophic support" to islet transplants as a means of maintaining graft viability. There may also be greater scope for gene therapy when the growth factor(s) have been isolated, purified, sequenced, and cloned. Images FIG. 2 FIG. 5 FIG. 6 FIG. 9 PMID:1364089

  2. Effect of Citrullus colocynthis aqueous seed extract on beta cell regeneration and intra-islet vasculature in alloxan induced diabetic male albino rats.

    PubMed

    Amin, Alia; Tahir, Mohammad; Lone, Khalid Pervez

    2017-05-01

    To observe the effect of Citrullus colocynthis on beta cell regeneration and intra-islet vasculature. This experimental study was conducted at the University of Health Sciences, Lahore, Pakistan, from February 2013 to January 2014. It comprised male wistar rats weighing 100-150gand aged 6-8 weeks. The animals were divided into 6 groups. Group A1 served as control. Diabetes was induced in groups A2, B2 and C2 using single intravenous injection of 50mg/kg of alloxan. Animals having fasting blood glucose>250mg/dl were considered diabetic. Diabetic rats in groups B2 and C2 and their controls B1 and C1 were given 1ml/kg and 2ml/kg of Citrullus colocynthis aqueous seed extract orally per day for 14 days. Animals were sacrifised on day 15. Of the 48 rats, there were 8(16.7%) in each group. Citrullus colocynthis has stabilized the body weight of rats and difference was statistically significant on days 7(p<0.013) and 14(p<0.001). Citrullus colocynthis significantly reduced (p<0.001) the fasting blood sugar levels in a dose- and time-dependent manner. It increased the islet diameter (p<0.001) and beta cell count (p<0.001). The number of intra-islet capillaries was increased in group C2, but the difference was not statistically significant (p>0.05). Citrullus colocynthis aqueous seed extract stabilised animal body weight and ameliorated hyperglycaemia in a dose- and time-dependent manner which was attributable to regenerative effect on beta cells and intra-islet vasculature.

  3. Palmitic acid-rich diet suppresses glucose-stimulated insulin secretion (GSIS) and induces endoplasmic reticulum (ER) stress in pancreatic islets in mice.

    PubMed

    Hirata, Takumi; Kawai, Toshihide; Hirose, Hiroshi; Tanaka, Kumiko; Kurosawa, Hideaki; Fujii, Chikako; Fujita, Haruhisa; Seto, Yoshiko; Matsumoto, Hideo; Itoh, Hiroshi

    2016-01-01

    The objective was to clarify whether dietary palmitic acid supplementation affects glucose-stimulated insulin secretion (GSIS) and the endoplasmic reticulum (ER) stress pathway in pancreatic islets in mice. Eight-week-old male C57BL/6J mice were randomly divided into three treatment diet groups: control diet, palmitic acid-supplemented diet (PAL) and oleic acid-supplemented diet (OLE). After 2 weeks of treatment, intraperitoneal glucose tolerance test and intraperitoneal insulin tolerance test were performed. GSIS was assessed by pancreatic perfusion in situ with basal (100 mg/dL) glucose followed by a high (300 mg/dL) glucose concentration. We measured mRNA levels of ER stress markers such as C/EBP homologous protein (CHOP), immunoglobulin heavy-chain binding protein (BIP) and X-box binding protein (XBP)-1 using real-time polymerase chain reaction (PCR) analyses in isolated islets. Immunohistochemical staining was also performed. Mice fed PAL showed significantly decreased glucose tolerance (p < 0.05). In the perfusion study, GSIS was significantly suppressed in the PAL group (p < 0.05). Semi-quantitative RT-PCR revealed that islet CHOP, BIP, and XBP-1 mRNA expression were significantly increased in the PAL group (p < 0.05). TUNEL-positive β-cells were not detected in all groups. Dietary palmitic acid-supplementation for 2 weeks might suppress GSIS and induce ER stress in pancreatic islets in mice, in the early stage of lipotoxicity.

  4. Assessing the effect of immunosuppression on engraftment of pancreatic islets

    PubMed Central

    Vallabhajosyula, Prashanth; Hirakata, Atsushi; Shimizu, Akira; Okumi, Masayoshi; Tchipashvili, Vaja; Hong, Hanzhou; Yamada, Kazuhiko; Sachs, David H.

    2013-01-01

    Objective In addition to ischemia and immunologic factors, immunosuppressive drugs have been suggested as a possible contributing factor to the loss of functional islets following allogeneic islet cell transplantation. Using our previously described islet-kidney transplantation model in miniature swine, we studied whether an islet toxic triple-drug immunosuppressive regimen (cyclosporine + azathioprine + prednisone) affects the islet engraftment process and thus long-term islet function. Design and Methods Donor animals underwent partial pancreatectomy, autologous islet preparation and injection of these islets under the autologous kidney capsule to prepare an islet-kidney (IK). Experimental animals received daily triple drug immunosuppression during the islet engraftment period. Control animals did not receive any immunosuppression during this period. Four to eight weeks later, these engrafted IK were transplanted across a minor histocompatibility mismatched barrier into pancreatectomized, nephrectomized recipient animals at an islet dose of ~ 4500 islet equivalents (IE)/kg recipient weight. Cyclosporine was administered for 12 days to the recipients to induce tolerance of the IK grafts and the animals were followed long-term. Results Diabetes was corrected by IK transplantation in all pancreatectomized recipients on both the control (n=3) and the experimental (n=4) arms of the study and all animals showed normal glucose regulation over the follow-up period. Intravenous glucose tolerance tests performed at 1, 2, > 3 months post-IK transplant showed essentially equivalent glycemic control in both control and experimental animals. Conclusion In this pre-clinical, in vivo large animal model of islet transplantation, the effect of triple drug immunosuppression on islet function does not negatively affect islet engraftment, as assessed by the long-term function of engrafted islets. PMID:23883972

  5. Characterization of pancreatic islet cell tumors and renal tumors induced by a combined treatment of streptozotocin and nicotinamide in male SD rats.

    PubMed

    Kato, Yuki; Masuno, Koichi; Fujisawa, Kae; Tsuchiya, Noriko; Torii, Mikinori; Hishikawa, Atsuko; Izawa, Takeshi; Kuwamura, Mitsuru; Yamate, Jyoji

    2017-09-05

    We herein investigated the histopathological features, including proliferative activity and immunoexpression, of pancreatic islet cell tumors (ICTs) in male SD rats induced by streptozotocin (STZ) and nicotinamide (NA), and discussed their relevance to biological behaviors and prognoses. A total of 70 and 43% of rats developed ICTs 37-45 weeks after the treatment with STZ (50 or 75mg/kg, i.v.) and NA (350mg/kg, twice, p.o.), respectively. Among the islet tumors observed in the STZ/NA-treated groups, 75% were adenomas, while 25% were carcinomas. Most STZ/NA-induced carcinomas were characterized by well-differentiated tumor cells with/without local invasion into the surrounding tissues, and weak proliferative activity. No outcome such as distance metastasis and death was noted. All of the ICTs strongly expressed insulin, part of which had hormone productivity; however there were no hypoglycemia-related clinical signs such as convulsion in these rats 36 weeks after the treatment. These results suggested that rat ICTs induced STZ/NA have small impact on biological activity or prognosis. STZ/NA treatment significantly increased of focal proliferative lesions in the kidney, liver and adrenal glands other than pancreatic islets. Of the STZ/NA-induced kidney tumors, more than 60% were renal cell adenomas, and many of them were basophilic type. The incidence of eosinophilic or clear cell type of tumors was less than 10%, respectively. Immunohistochemical analyses revealed that many of the STZ/NA-induced basophilic type of renal tumors were derived from proximal tubules, whereas the clear cell and eosinophilic types were derived from collecting tubules. Copyright © 2017 Elsevier GmbH. All rights reserved.

  6. UCP2 mRNA expression is dependent on glucose metabolism in pancreatic islets

    SciTech Connect

    Dalgaard, Louise T.

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer UCP2 mRNA levels are decreased in islets of Langerhans from glucokinase deficient mice. Black-Right-Pointing-Pointer UCP2 mRNA up-regulation by glucose is dependent on glucokinase. Black-Right-Pointing-Pointer Absence of UCP2 increases GSIS of glucokinase heterozygous pancreatic islets. Black-Right-Pointing-Pointer This may protect glucokinase deficient mice from hyperglycemic damages. -- Abstract: Uncoupling Protein 2 (UCP2) is expressed in the pancreatic {beta}-cell, where it partially uncouples the mitochondrial proton gradient, decreasing both ATP-production and glucose-stimulated insulin secretion (GSIS). Increased glucose levels up-regulate UCP2 mRNA and protein levels, but the mechanism for UCP2 up-regulation in response to increased glucose is unknown. The aim was to examine the effects of glucokinase (GK) deficiency on UCP2 mRNA levels and to characterize the interaction between UCP2 and GK with regard to glucose-stimulated insulin secretion in pancreatic islets. UCP2 mRNA expression was reduced in GK+/- islets and GK heterozygosity prevented glucose-induced up-regulation of islet UCP2 mRNA. In contrast to UCP2 protein function UCP2 mRNA regulation was not dependent on superoxide generation, but rather on products of glucose metabolism, because MnTBAP, a superoxide dismutase mimetic, did not prevent the glucose-induced up-regulation of UCP2. Glucose-stimulated insulin secretion was increased in UCP2-/- and GK+/- islets compared with GK+/- islets and UCP2 deficiency improved glucose tolerance of GK+/- mice. Accordingly, UCP2 deficiency increased ATP-levels of GK+/- mice. Thus, the compensatory down-regulation of UCP2 is involved in preserving the insulin secretory capacity of GK mutant mice and might also be implicated in limiting disease progression in MODY2 patients.

  7. Glucose cycling in islets from healthy and diabetic rats

    SciTech Connect

    Khan, A.; Chandramouli, V.; Ostenson, C.G.; Loew, H.L.; Landau, B.R.; Efendic, S. )

    1990-04-01

    Pancreatic islets from healthy (control) and neonatally streptozocin-induced diabetic (STZ-D) rats, a model for non-insulin-dependent diabetes mellitus, were incubated with {sup 3}H{sub 2}O and 5.5 or 16.7 mM glucose. At 5.5 mM glucose, no detectable ({sup 3}H)glucose was formed. At 16.7 mM, 2.2 patom.islet-1.h-1 of {sup 3}H was incorporated into glucose by the control islets and 5.4 patom.islet-1.h-1 by STZ-D islets. About 75% of the {sup 3}H was bound to carbon-2 of the glucose. Glucose utilization was 35.3 pmol.islet-1.h-1 by the control and 19.0 pmol.islet-1.h-1 by the STZ-D islets. Therefore, 4.5% of the glucose-6-phosphate formed by the control islets and 15.7% by the STZ-D islets was dephosphorylated. This presumably occurred in the beta-cells of the islets catalyzed by glucose-6-phosphatase. An increased glucose cycling, i.e., glucose----glucose-6-phosphate----glucose, in islets of STZ-D rats may contribute to the decreased insulin secretion found in these animals.

  8. Macroporous Three Dimensional PDMS Scaffolds for Extrahepatic Islet Transplantation

    PubMed Central

    Pedraza, Eileen; Brady, Ann-Christina; Fraker, Christopher A.; Molano, R. Damaris; Sukert, Steven; Berman, Dora M.; Kenyon, Norma S.; Pileggi, Antonello; Ricordi, Camillo; Stabler, Cherie L.

    2015-01-01

    Clinical islet transplantation has demonstrated success in treating type 1 diabetes. A current limitation is the intrahepatic portal vein transplant site, which is prone to mechanical stress and inflammation. Transplantation of pancreatic islets into alternative sites is preferable, but challenging, as it may require a three-dimensional vehicle to confer mechanical protection and to confine islets to a well-defined, retrievable space where islet neovascularization can occur. We have fabricated biostable, macroporous scaffolds from poly(dimethylsiloxane) (PDMS) and investigated islet retention and distribution, metabolic function, and glucose-dependent insulin secretion within these materials. Islets from multiple sources, including rodents, non-human primates, and humans, were tested in vitro. We observed high islet retention and distribution within PDMS scaffolds, with retention of small islets (< 100 µm) improved through the post-loading addition of fibrin gel. Islets loaded within PDMS scaffolds exhibited viability and function comparable to standard culture conditions when incubated under normal oxygen tensions, but displayed improved viability compared to standard two-dimensional culture controls under low oxygen tensions. In vivo efficacy of scaffolds to support islet grafts was evaluated after transplantation in the omental pouch of chemically-induced diabetic syngeneic rats, which promptly achieved normoglycemia. Collectively, these results are promising in that they indicate the potential for transplanting islets into a clinically relevant, extrahepatic site that provides spatial distribution of islets, as well as intra-device vascularization. PMID:23031502

  9. Islet Cell Transplantation

    MedlinePlus

    ... person who has type 1 diabetes must take insulin daily to live. Transplanted islet cells, however, can take over the work of the destroyed cells. The beta cells in these islets will begin to make and release insulin. Researchers hope islet transplantation will help people with ...

  10. Protective Role of Nuclear Factor E2-Related Factor 2 against Acute Oxidative Stress-Induced Pancreatic β-Cell Damage

    PubMed Central

    Fu, Jingqi; Zheng, Hongzhi; Wang, Huihui; Yang, Bei; Zhao, Rui; Lu, Chunwei; Liu, Zhiyuan; Hou, Yongyong; Xu, Yuanyuan; Zhang, Qiang; Qu, Weidong; Pi, Jingbo

    2015-01-01

    Oxidative stress is implicated in the pathogenesis of pancreatic β-cell dysfunction that occurs in both type 1 and type 2 diabetes. Nuclear factor E2-related factor 2 (NRF2) is a master regulator in the cellular adaptive response to oxidative stress. The present study found that MIN6 β-cells with stable knockdown of Nrf2 (Nrf2-KD) and islets isolated from Nrf2-knockout mice expressed substantially reduced levels of antioxidant enzymes in response to a variety of stressors. In scramble MIN6 cells or wild-type islets, acute exposure to oxidative stressors, including hydrogen peroxide (H2O2) and S-nitroso-N-acetylpenicillamine, resulted in cell damage as determined by decrease in cell viability, reduced ATP content, morphology changes of islets, and/or alterations of apoptotic biomarkers in a concentration- and/or time-dependent manner. In contrast, silencing of Nrf2 sensitized MIN6 cells or islets to the damage. In addition, pretreatment of MIN6 β-cells with NRF2 activators, including CDDO-Im, dimethyl fumarate (DMF), and tert-butylhydroquinone (tBHQ), protected the cells from high levels of H2O2-induced cell damage. Given that reactive oxygen species (ROS) are involved in regulating glucose-stimulated insulin secretion (GSIS) and persistent activation of NRF2 blunts glucose-triggered ROS signaling and GSIS, the present study highlights the distinct roles that NRF2 may play in pancreatic β-cell dysfunction that occurs in different stages of diabetes. PMID:25949772

  11. Hydrogen Induced Damage in Pipeline Steels

    NASA Astrophysics Data System (ADS)

    Angus, Garrett R.

    The hydrogen induced cracking (HIC) resistance of several grades of plate steels was investigated using electrolytic hydrogen charging. HIC generated by electrolytic charging was also compared to the industrial standard test for HIC, the NACE standard TM0284. The electrolytic charging (EC) apparatus was designed to optimize the reproducibility of the HIC results and the robustness of the components during long charging times. A characterization study on the EC apparatus was undertaken. Alterations to applied current density and charging time were conducted on a highly susceptible plate steel, 100XF, to assess HIC damage as a function of charging conditions. Intermediate current densities of 10 to 15 mA/cm2 produced the greatest extent of cracking without significant corrosion related surface damage. The hydrogen charging time did not greatly affect the extent and depth of cracking for test times between 24 to 48 hours. Thus, for subsequent experiments, the applied current density was set to 15 mA/cm2 and the charging time was set to 24 hours. Plate steel grades X52, X60, X70, and 100XF were prestrained in tension to various levels and then electrolytically charged with hydrogen or tested with the NACE standard TM0284 test (solution A) saturated with H2S(g) to induce HIC. Prestrain was introduced to assess its impact on HIC. Hydrogen damage was quantified with the crack ratios defined in the NACE Standard TM0284. The results from the EC and NACE methods were very comparable to one, with respect to the magnitude of cracking and the trends between alloy and pre-strain conditions observed. Both methods showed that HIC substantially increased for the high strength 100XF steel compared to the lower strength alloys. This is consistent with NACE recommendations for HIC resistance steels, which suggests that alloy strength should be less than 116 ksi (800 MPa) or 248 HV (22 HRC). The HIC results were largely independent of the pre-strain levels imposed within the

  12. Copper deficiency potentiates ethanol induced liver damage

    SciTech Connect

    Zidenberg-Cherr, S.; Han, B.; Graham, T.W.; Keen, C.L. )

    1992-02-26

    Copper sufficient (+Cu) and deficient ({minus}Cu) rats were fed liquid diets with EtOH or dextrose at 36% of kcals for 2 mo. Consumption of either the {minus}Cu diet or EtOH resulted in lower liver CuZn superoxide dismutase (CuZnSOD) and glutathione peroxidase (GPx) activities were lowest in EtOH/{minus}Cu rats; being 20% and 50% of control values, respectively. Ethanol resulted in higher MnSOD activity in +Cu and {minus}Cu rats. Low Cu intake as well as EtOH resulted in lower mitochondrial (Mit) TBARS relative to controls. TBARS were lowest in Mit from EtOH/{minus}Cu rats. Microsomal (Micro) TBARS were lower in {minus}Cu and EtOH-fed rats than in controls. The peroxidizability index (PI) was calculated as an index of substrate availability for lipid peroxidation. Ethanol feeding resulted in lower PI's in Mit and Micro than measured in non-EtOH rats. There was a positive correlation between Micro PI's and TBARS. These results show that despite reductions in components of antioxidant defense, compensatory mechanism arise resulting in reduction in peroxidation targets and/or an increase in alternate free radical quenching factors. Histological examination demonstrated increased portal and intralobular connective tissue and cell necrosis in EtOH/{minus}Cu rats, suggesting that Cu may be a critical modulator of EtOH induced tissue damage.

  13. β-Cell Failure in Diet-Induced Obese Mice Stratified According to Body Weight Gain: Secretory Dysfunction and Altered Islet Lipid Metabolism Without Steatosis or Reduced β-Cell Mass

    PubMed Central

    Peyot, Marie-Line; Pepin, Emilie; Lamontagne, Julien; Latour, Martin G.; Zarrouki, Bader; Lussier, Roxane; Pineda, Marco; Jetton, Thomas L.; Madiraju, S.R. Murthy; Joly, Erik; Prentki, Marc

    2010-01-01

    OBJECTIVE C57Bl/6 mice develop obesity and mild hyperglycemia when fed a high-fat diet (HFD). Although diet-induced obesity (DIO) is a widely studied model of type 2 diabetes, little is known about β-cell failure in these mice. RESEARCH DESIGN AND METHODS DIO mice were separated in two groups according to body weight gain: low- and high-HFD responders (LDR and HDR). We examined whether mild hyperglycemia in HDR mice is due to reduced β-cell mass or function and studied islet metabolism and signaling. RESULTS HDR mice were more obese, hyperinsulinemic, insulin resistant, and hyperglycemic and showed a more altered plasma lipid profile than LDR. LDR mice largely compensated insulin resistance, whereas HDR showed perturbed glucose homeostasis. Neither LDR nor HDR mice showed reduced β-cell mass, altered islet glucose metabolism, and triglyceride deposition. Insulin secretion in response to glucose, KCl, and arginine was impaired in LDR and almost abolished in HDR islets. Palmitate partially restored glucose- and KCl-stimulated secretion. The glucose-induced rise in ATP was reduced in both DIO groups, and the glucose-induced rise in Ca2+ was reduced in HDR islets relatively to LDR. Glucose-stimulated lipolysis was decreased in LDR and HDR islets, whereas fat oxidation was increased in HDR islets only. Fatty acid esterification processes were markedly diminished, and free cholesterol accumulated in HDR islets. CONCLUSIONS β-Cell failure in HDR mice is not due to reduced β-cell mass and glucose metabolism or steatosis but to a secretory dysfunction that is possibly due to altered ATP/Ca2+ and lipid signaling, as well as free cholesterol deposition. PMID:20547980

  14. Impact of Size in Pancreatic Islet Transplantation and Potential Interventions to Improve Outcome

    PubMed Central

    Zorzi, Daria; Phan, Tammy; Sequi, Marco; Lin, Yong; Freeman, Daniel H.; Cicalese, Luca; Rastellini, Cristiana

    2015-01-01

    Better results have been recently reported in clinical pancreatic islet transplantation (ITX) due mostly to improved isolation techniques and immunosuppression; however, some limitations still exist. It is known that following transplantation from 30 to 60% of the islets is lost. In our study, we have investigated: 1) the role of size as a factor affecting islet engraftment and, 2) potential procedural manipulations to increase the number of smaller functional islets that can be transplanted. C57/BL10 mice were used as donors and recipients in a syngeneic islet transplant model. Isolated islets were divided by size (large, >300 µm; medium 150–300 µm; small, ρ50 µm). Each size was transplanted in chemically induced diabetic mice as full (600 IEq), suboptimal (400 IEq), and marginal mass (200 IEq). Control animals received all size islets. Engraftment was defined as reversal of diabetes by day 7 post-transplantation. When the superiority of smaller islets was observed, strategies of over-digestion and fragmentation were adopted during islet isolation in the attempt to reduce islet size and improve engraftment. Smaller islets were significantly superior in engraftment as compared to medium, large, and control (all sizes) groups. This was more evident when marginal mass data were compared. In all masses, success decreased as islet sizes increased. Once islets were engrafted, functionality was not affected by size. When larger islets were fragmented, a significant decrease in islet functionality was observed. On the contrary, if pancreata were slightly over-digested, although not as successful as small naive islets, an increase in engraftment was observed when compared to the control group. In conclusion, smaller islets are superior in engraftment following islet transplantation. Fragmentation has a deleterious effect on islet engraftment. Islet isolations can be performed reducing islet size with slight over-digestion and it can be safely adopted to improve

  15. Acrylonitrile-induced oxidative DNA damage in rat astrocytes.

    PubMed

    Pu, Xinzhu; Kamendulis, Lisa M; Klaunig, James E

    2006-10-01

    Chronic administration of acrylonitrile results in a dose-related increase in astrocytomas in rat brain, but the mechanism of acrylonitrile carcinogenicity is not fully understood. The potential of acrylonitrile or its metabolites to induce direct DNA damage as a mechanism for acrylonitrile carcinogenicity has been questioned, and recent studies indicate that the mechanism involves the induction of oxidative stress in rat brain. The present study examined the ability of acrylonitrile to induce DNA damage in the DI TNC1 rat astrocyte cell line using the alkaline Comet assay. Oxidized DNA damage also was evaluated using formamidopyrimidine DNA glycosylase treatment in the modified Comet assay. No increase in direct DNA damage was seen in astrocytes exposed to sublethal concentrations of acrylonitrile (0-1.0 mM) for 24 hr. However, acrylonitrile treatment resulted in a concentration-related increase in oxidative DNA damage after 24 hr. Antioxidant supplementation in the culture media (alpha-tocopherol, (-)-epigallocathechin-3 gallate, or trolox) reduced acrylonitrile-induced oxidative DNA damage. Depletion of glutathione using 0.1 mM DL-buthionine-[S,R]-sulfoximine increased acrylonitrile-induced oxidative DNA damage (22-46%), while cotreatment of acrylonitrile with 2.5 mM L-2-oxothiazolidine-4-carboxylic acid, a precursor for glutathione biosynthesis, significantly reduced acrylonitrile-induced oxidative DNA damage (7-47%). Cotreatment of acrylonitrile with 0.5 mM 1-aminobenzotriazole, a suicidal inhibitor of cytochrome P450, prevented the oxidative DNA damage produced by acrylonitrile. Cyanide (0.1-0.5 mM) increased oxidative DNA damage (44-160%) in astrocytes. These studies demonstrate that while acrylonitrile does not directly damage astrocyte DNA, it does increase oxidative DNA damage. The oxidative DNA damage following acrylonitrile exposure appears to arise mainly through the P450 metabolic pathway; moreover, glutathione depletion may contribute to the

  16. A continuum damage model of fatigue-induced damage in laminated composites

    NASA Technical Reports Server (NTRS)

    Harris, Charles E.; Allen, David H.

    1988-01-01

    A model is presented which predicts the stress-strain behavior of continuous fiber reinforced laminated composites in the presence of microstructural damage. The model is based on the concept of continuum damage mechanics and uses internal state variables to characterize the various damage modes. The associated internal state variable growth laws are mathematical models of the loading history induced development of microstructural damage. The model is demonstrated by using it to predict the response of damaged AS-4/3502 graphite/epoxy laminate panels.

  17. The transcription factor HNF1α induces expression of angiotensin-converting enzyme 2 (ACE2) in pancreatic islets from evolutionarily conserved promoter motifs.

    PubMed

    Pedersen, Kim Brint; Chhabra, Kavaljit H; Nguyen, Van K; Xia, Huijing; Lazartigues, Eric

    2013-11-01

    Pancreatic angiotensin-converting enzyme 2 (ACE2) has previously been shown to be critical for maintaining glycemia and β-cell function. Efforts to maintain or increase ACE2 expression in pancreatic β-cells might therefore have therapeutic potential for treating diabetes. In our study, we investigated the transcriptional role of hepatocyte nuclear factor 1α (HNF1α) and hepatocyte nuclear factor 1β (HNF1β) in induction of ACE2 expression in insulin-secreting cells. A deficient allele of HNF1α or HNF1β causes maturity-onset diabetes of the young (MODY) types 3 and 5, respectively, in humans. We found that ACE2 is primarily transcribed from the proximal part of the ACE2 promoter in the pancreas. In the proximal part of the human ACE2 promoter, we further identified three functional HNF1 binding sites, as they have binding affinity for HNF1α and HNF1β and are required for induction of promoter activity by HNF1β in insulinoma cells. These three sites are well-conserved among mammalian species. Both HNF1α and HNF1β induce expression of ACE2 mRNA and lead to elevated levels of ACE2 protein and ACE2 enzymatic activity in insulinoma cells. Furthermore, HNF1α dose-dependently increases ACE2 expression in primary pancreatic islet cells. We conclude that HNF1α can induce the expression of ACE2 in pancreatic islet cells via evolutionarily conserved HNF1 binding sites in the ACE2 promoter. Potential therapeutics aimed at counteracting functional HNF1α depletion in diabetes and MODY3 will thus have ACE2 induction in pancreatic islets as a likely beneficial effect.

  18. Heat induced damage detection in composite materials by terahertz radiation

    NASA Astrophysics Data System (ADS)

    Radzieński, Maciej; Mieloszyk, Magdalena; Rahani, Ehsan Kabiri; Kundu, Tribikram; Ostachowicz, Wiesław

    2015-03-01

    In recent years electromagnetic Terahertz (THz) radiation or T-ray has been increasingly used for nondestructive evaluation of various materials such as polymer composites and porous foam tiles in which ultrasonic waves cannot penetrate but T-ray can. Most of these investigations have been limited to mechanical damage detection like inclusions, cracks, delaminations etc. So far only a few investigations have been reported on heat induced damage detection. Unlike mechanical damage the heat induced damage does not have a clear interface between the damaged part and the surrounding intact material from which electromagnetic waves can be reflected back. Difficulties associated with the heat induced damage detection in composite materials using T-ray are discussed in detail in this paper. T-ray measurements are compared for different levels of heat exposure of composite specimens.

  19. Changes in histochemically detectable calcium and zinc during tolbutamide-induced degranulation and subsequent regranulation of rat pancreatic islets.

    PubMed

    Wolters, G H; Pasma, A; Wiegman, J B; Konijnendijk, W

    1983-01-01

    Secretory granules of pancreatic B-cells contain high concentrations of zinc and calcium. The effect of gradual degranulation (induced by tolbutamide over a period of 3 days) and the subsequent regranulation (over a period of 4 days) on the histochemically detectable zinc (Zn) and calcium (Ca) content of B-cells was investigated. Zn was stained by dithizone, Ca by glyoxal-bis-(2-hydroxyanil), (GBHA), and B-granules by aldehyde fuchsin (AF). The staining intensities were determined cytophotometrically. A decrease of the granulation by 50% causes a comparable decrease of the Zn content. Almost complete degranulations, however, hardly further diminished the Zn content. Regranulation restores the Zn content parallel to the granulation. The presence of 40% of the initial Zn content in degranulated B-cells suggests the existence of a non-granular Zn fraction. The Zn content of B-cells may be partly involved in the storage of insulin as a Zn-insulin complex in the secretory vesicles. A-cells, however, contain even more (+ 30%) Zn than B-cells. Degranulation of B-cells is accompanied by a moderate decrease of the zinc content of the A-cells. The function of Zn in A-cells is completely unknown. Degranulation of B-cells causes the GBHA-Ca content to decrease to a very low level parallel to the AF-positive granulation. During regranulation the GBHA-Ca content restores parallel to the granulation and reaches after complete regranulation a slightly higher level than in untreated control rats. Almost complete disappearance of CBHA-Ca in the B-cells is accompanied by a decrease of the total islet calcium content of 33%. The results indicate that GBHA stains a Ca fraction which is mainly localized to the secretory granules. The stainability of granular Ca by GBHA is probably based on: a) the high Ca concentration in the granules, b) the presence of ionized Ca in the granules, due to the low intragranular pH, and c) on the properties of GBHA, which stains, under conditions used

  20. Mechanisms of Diabetes-Induced Liver Damage

    PubMed Central

    Mohamed, Jamaludin; Nazratun Nafizah, A. H.; Zariyantey, A. H.; Budin, S. B.

    2016-01-01

    Diabetes mellitus is a non-communicable disease that occurs in both developed and developing countries. This metabolic disease affects all systems in the body, including the liver. Hyperglycaemia, mainly caused by insulin resistance, affects the metabolism of lipids, carbohydrates and proteins and can lead to non-alcoholic fatty liver disease, which can further progress to non-alcoholic steatohepatitis, cirrhosis and, finally, hepatocellular carcinomas. The underlying mechanism of diabetes that contributes to liver damage is the combination of increased oxidative stress and an aberrant inflammatory response; this activates the transcription of pro-apoptotic genes and damages hepatocytes. Significant involvement of pro-inflammatory cytokines—including interleukin (IL)-1β, IL-6 and tumour necrosis factor-α—exacerbates the accumulation of oxidative damage products in the liver, such as malondialdehyde, fluorescent pigments and conjugated dienes. This review summarises the biochemical, histological and macromolecular changes that contribute to oxidative liver damage among diabetic individuals. PMID:27226903

  1. Relationship of gonadal activity and chemotherapy-induced gonadal damage

    SciTech Connect

    Rivkees, S.A.; Crawford, J.D.

    1988-04-08

    The authors tested the hypothesis that chemotherapy-induced gonadal damage is proportional to the degree of gonadal activity during treatment. Thirty studies that evaluated gonadal function after cyclophosphamide therapy for renal disease or combination chemotherapy for Hodgkin's disease or acute lymphocytic leukemia provided data for analysis. Data were stratified according to sex, illness, chemotherapeutic regimen and dose, and pubertal stage at the time of treatment. Chemotherapy-induced damage was more likely to occur in patients who were treated when sexually mature compared with those who were treated when prepubertal. Males were significantly more frequently affected than females when treated for renal disease of Hodgkin's disease. Chemotherapy-induced damage was also more likely to occur when patients were treated with large doses of alkylating agents. These data suggest that chemotherapy-induced damage is proportional to gonadal activity. Further efforts are needed to test whether induced gonadal quiescence during chemotherapy will reduce the strikingly high incidence of gonadal failure following chemotherapy.

  2. An inducible long noncoding RNA amplifies DNA damage signaling.

    PubMed

    Schmitt, Adam M; Garcia, Julia T; Hung, Tiffany; Flynn, Ryan A; Shen, Ying; Qu, Kun; Payumo, Alexander Y; Peres-da-Silva, Ashwin; Broz, Daniela Kenzelmann; Baum, Rachel; Guo, Shuling; Chen, James K; Attardi, Laura D; Chang, Howard Y

    2016-11-01

    Long noncoding RNAs (lncRNAs) are prevalent genes with frequently precise regulation but mostly unknown functions. Here we demonstrate that lncRNAs guide the organismal DNA damage response. DNA damage activated transcription of the DINO (Damage Induced Noncoding) lncRNA via p53. DINO was required for p53-dependent gene expression, cell cycle arrest and apoptosis in response to DNA damage, and DINO expression was sufficient to activate damage signaling and cell cycle arrest in the absence of DNA damage. DINO bound to p53 protein and promoted its stabilization, mediating a p53 auto-amplification loop. Dino knockout or promoter inactivation in mice dampened p53 signaling and ameliorated acute radiation syndrome in vivo. Thus, inducible lncRNA can create a feedback loop with its cognate transcription factor to amplify cellular signaling networks.

  3. Damage-induced nonassociated inelastic flow in rock salt

    SciTech Connect

    Chan, K.S.; Bodner, S.R.; Brodsky, N.S.; Fossum, A.F.

    1993-06-01

    The multi-mechanism deformation coupled fracture model recently developed by CHAN, et al. (1992), for describing time-dependent, pressure-sensitive inelastic flow and damage evolution in crystalline solids was evaluated against triaxial creep experiments on rock salt. Guided by experimental observations, the kinetic equation and the flow law for damage-induced inelastic flow in the model were modified to account for the development of damage and inelastic dilatation in the transient creep regime. The revised model was then utilized to obtain the creep response and damage evolution in rock salt as a function of confining pressure and stress difference. Comparison between model calculation and experiment revealed that damage-induced inelastic flow is nonassociated, dilatational, and contributes significantly to the macroscopic strain rate observed in rock salt deformed at low confining pressures. The inelastic strain rate and volumetric strain due to damage decrease with increasing confining pressures, and all are suppressed at sufficiently high confining pressures.

  4. An inducible long noncoding RNA amplifies DNA damage signaling

    PubMed Central

    Schmitt, Adam M.; Garcia, Julia T.; Hung, Tiffany; Flynn, Ryan A.; Shen, Ying; Qu, Kun; Payumo, Alexander Y.; Peres-da-Silva, Ashwin; Broz, Daniela Kenzelmann; Baum, Rachel; Guo, Shuling; Chen, James K.; Attardi, Laura D.; Chang, Howard Y.

    2016-01-01

    Long noncoding RNAs (lncRNAs) are prevalent genes with frequently exquisite regulation but mostly unknown functions. Here we demonstrate a role of lncRNAs in guiding organismal DNA damage response. DNA damage activates transcription of DINO (Damage Induced NOncoding) via p53. DINO is required for p53-dependent gene expression, cell cycle arrest, and apoptosis in response to DNA damage, and DINO expression suffice to activate damage signaling and cell cycle arrest in the absence of DNA damage. DINO binds to and promotes p53 protein stabilization, mediating a p53 auto-amplification loop. Dino knockout or promoter inactivation in mice dampens p53 signaling and ameliorates acute radiation syndrome in vivo. Thus, inducible lncRNA can create a feedback loop with its cognate transcription factor to amplify cellular signaling networks. PMID:27668660

  5. Justifying clinical trials for porcine islet xenotransplantation.

    PubMed

    Ellis, Cara E; Korbutt, Gregory S

    2015-01-01

    The development of the Edmonton Protocol encouraged a great deal of optimism that a cell-based cure for type I diabetes could be achieved. However, donor organ shortages prevent islet transplantation from being a widespread solution as the supply cannot possibly equal the demand. Porcine islet xenotransplantation has the potential to address these shortages, and recent preclinical and clinical trials show promising scientific support. Consequently, it is important to consider whether the current science meets the ethical requirements for moving toward clinical trials. Despite the potential risks and the scientific unknowns that remain to be investigated, there is optimism regarding the xenotransplantation of some types of tissue, and enough evidence has been gathered to ethically justify clinical trials for the most safe and advanced area of research, porcine islet transplantation. Researchers must make a concerted effort to maintain a positive image for xenotransplantation, as a few well-publicized failed trials could irrevocably damage public perception of xenotransplantation. Because all of society carries the burden of risk, it is important that the public be involved in the decision to proceed. As new information from preclinical and clinical trials develops, policy decisions should be frequently updated. If at any point evidence shows that islet xenotransplantation is unsafe, then clinical trials will no longer be justified and they should be halted. However, as of now, the expected benefit of an unlimited supply of islets, combined with adequate informed consent, justifies clinical trials for islet xenotransplantation.

  6. Antibody Response to Serpin B13 Induces Adaptive Changes in Mouse Pancreatic Islets and Slows Down the Decline in the Residual Beta Cell Function in Children with Recent Onset of Type 1 Diabetes Mellitus.

    PubMed

    Kryvalap, Yury; Lo, Chi-Wen; Manuylova, Ekaterina; Baldzizhar, Raman; Jospe, Nicholas; Czyzyk, Jan

    2016-01-01

    Type 1 diabetes mellitus (T1D) is characterized by a heightened antibody (Ab) response to pancreatic islet self-antigens, which is a biomarker of progressive islet pathology. We recently identified a novel antibody to clade B serpin that reduces islet-associated T cell accumulation and is linked to the delayed onset of T1D. As natural immunity to clade B arises early in life, we hypothesized that it may influence islet development during that time. To test this possibility healthy young Balb/c male mice were injected with serpin B13 mAb or IgG control and examined for the number and cellularity of pancreatic islets by immunofluorescence and FACS. Beta cell proliferation was assessed by measuring nucleotide analog 5-ethynyl-2'-deoxyuridine (5-EdU) incorporation into the DNA and islet Reg gene expression was measured by real time PCR. Human studies involved measuring anti-serpin B13 autoantibodies by Luminex. We found that injecting anti-serpin B13 monoclonal Ab enhanced beta cell proliferation and Reg gene expression, induced the generation of ∼80 pancreatic islets per animal, and ultimately led to increase in the beta cell mass. These findings are relevant to human T1D because our analysis of subjects just diagnosed with T1D revealed an association between baseline anti-serpin activity and slower residual beta cell function decline in the first year after the onset of diabetes. Our findings reveal a new role for the anti-serpin immunological response in promoting adaptive changes in the endocrine pancreas and suggests that enhancement of this response could potentially help impede the progression of T1D in humans.

  7. Antibody Response to Serpin B13 Induces Adaptive Changes in Mouse Pancreatic Islets and Slows Down the Decline in the Residual Beta Cell Function in Children with Recent Onset of Type 1 Diabetes Mellitus*

    PubMed Central

    Kryvalap, Yury; Lo, Chi-Wen; Manuylova, Ekaterina; Baldzizhar, Raman; Jospe, Nicholas; Czyzyk, Jan

    2016-01-01

    Type 1 diabetes mellitus (T1D) is characterized by a heightened antibody (Ab) response to pancreatic islet self-antigens, which is a biomarker of progressive islet pathology. We recently identified a novel antibody to clade B serpin that reduces islet-associated T cell accumulation and is linked to the delayed onset of T1D. As natural immunity to clade B arises early in life, we hypothesized that it may influence islet development during that time. To test this possibility healthy young Balb/c male mice were injected with serpin B13 mAb or IgG control and examined for the number and cellularity of pancreatic islets by immunofluorescence and FACS. Beta cell proliferation was assessed by measuring nucleotide analog 5-ethynyl-2′-deoxyuridine (5-EdU) incorporation into the DNA and islet Reg gene expression was measured by real time PCR. Human studies involved measuring anti-serpin B13 autoantibodies by Luminex. We found that injecting anti-serpin B13 monoclonal Ab enhanced beta cell proliferation and Reg gene expression, induced the generation of ∼80 pancreatic islets per animal, and ultimately led to increase in the beta cell mass. These findings are relevant to human T1D because our analysis of subjects just diagnosed with T1D revealed an association between baseline anti-serpin activity and slower residual beta cell function decline in the first year after the onset of diabetes. Our findings reveal a new role for the anti-serpin immunological response in promoting adaptive changes in the endocrine pancreas and suggests that enhancement of this response could potentially help impede the progression of T1D in humans. PMID:26578518

  8. Under a nonadherent state, bone marrow mesenchymal stem cells can be efficiently induced into functional islet-like cell clusters to normalize hyperglycemia in mice: a control study.

    PubMed

    Zhang, Yihua; Dou, Zhongying

    2014-05-08

    Bone marrow mesenchymal stem cells (BMSCs) possess low immunogenicity and immunosuppression as an allograft, can differentiate into insulin-producing cells (IPCs) by in vitro induction, and may be a valuable cell source to regenerate pancreatic islets. However, the very low differentiation efficiency of BMSCs towards IPCs under adherent induction has thus far hindered the clinical exploitation of these cells. The aim of this study is to explore a new way to efficiently induce BMSCs into IPCs and lay the groundwork for their clinical exploitation. In comparison with adherent induction, BMSCs of human first-trimester abortus (hfBMSCs) under a nonadherent state were induced towards IPCs in noncoated plastic dishes using a three-stage induction procedure developed by the authors. Induction effects were evaluated by statistics of the cell clustering rate of induced cells, and ultrastructural observation, dithizone staining, quantitative polymerase chain reaction and immunofluorescence assay, insulin and c-peptide release under glucose stimulus of cell clusters, as well as transplantation test of the cell clusters in diabetic model mice. With (6.175 ± 0.263) × 105 cells in 508.5 ± 24.5 cell clusters, (3.303 ± 0.331) × 105 single cells and (9.478 ± 0.208) × 105 total cell count on average, 65.08 ± 2.98% hfBMSCs differentiated into pancreatic islet-like cell clusters after nonadherent induction. With (3.993 ± 0.344) × 105 cells in 332.3 ± 41.6 cell clusters, (5.437 ± 0.434) × 105 single cells and (9.430 ± 0.340) × 105 total cell count on average, 42.37 ± 3.70% hfBMSCs differentiated into pancreatic islet-like cell clusters after adherent induction (P < 0.01, n = 10). The former is significantly higher than the latter. Calculated according to the cell clustering rate and IPC percentage in the cell clusters, 29.80 ± 3.95% hfBMSCs differentiated into IPCs after nonadherent induction

  9. Under a nonadherent state, bone marrow mesenchymal stem cells can be efficiently induced into functional islet-like cell clusters to normalize hyperglycemia in mice: a control study

    PubMed Central

    2014-01-01

    Introduction Bone marrow mesenchymal stem cells (BMSCs) possess low immunogenicity and immunosuppression as an allograft, can differentiate into insulin-producing cells (IPCs) by in vitro induction, and may be a valuable cell source to regenerate pancreatic islets. However, the very low differentiation efficiency of BMSCs towards IPCs under adherent induction has thus far hindered the clinical exploitation of these cells. The aim of this study is to explore a new way to efficiently induce BMSCs into IPCs and lay the groundwork for their clinical exploitation. Methods In comparison with adherent induction, BMSCs of human first-trimester abortus (hfBMSCs) under a nonadherent state were induced towards IPCs in noncoated plastic dishes using a three-stage induction procedure developed by the authors. Induction effects were evaluated by statistics of the cell clustering rate of induced cells, and ultrastructural observation, dithizone staining, quantitative polymerase chain reaction and immunofluorescence assay, insulin and c-peptide release under glucose stimulus of cell clusters, as well as transplantation test of the cell clusters in diabetic model mice. Results With (6.175 ± 0.263) × 105 cells in 508.5 ± 24.5 cell clusters, (3.303 ± 0.331) × 105 single cells and (9.478 ± 0.208) × 105 total cell count on average, 65.08 ± 2.98% hfBMSCs differentiated into pancreatic islet-like cell clusters after nonadherent induction. With (3.993 ± 0.344) × 105 cells in 332.3 ± 41.6 cell clusters, (5.437 ± 0.434) × 105 single cells and (9.430 ± 0.340) × 105 total cell count on average, 42.37 ± 3.70% hfBMSCs differentiated into pancreatic islet-like cell clusters after adherent induction (P < 0.01, n = 10). The former is significantly higher than the latter. Calculated according to the cell clustering rate and IPC percentage in the cell clusters, 29.80 ± 3.95% hfBMSCs differentiated into IPCs

  10. RNF111-dependent neddylation activates DNA damage-induced ubiquitination

    PubMed Central

    Ma, Teng; Chen, Yibin; Zhang, Feng; Yang, Chao-Yie; Wang, Shaomeng; Yu, Xiaochun

    2013-01-01

    Summary Ubiquitin-like proteins have been shown to be covalently conjugated to targets. However, the functions of these ubiquitin-like proteins are largely unknown. Here, we have screened most known ubiquitin-like proteins after DNA damage and found that NEDD8 is involved in the DNA damage response. Following various DNA damage stimuli, NEDD8 accumulated at DNA damage sites, and this accumulation was dependent on an E2 enzyme UBE2M and an E3 ubiquitin ligase RNF111. We further found that histone H4 was polyneddylated in response to DNA damage, and NEDD8 was conjugated to the N-terminal lysine residues of H4. Interestingly, the DNA damage-induced polyneddylation chain could be recognized by the MIU (Motif Interacting with Ubiquitin) domain of RNF168. Loss of DNA damage-induced neddylation negatively regulated DNA damage-induced foci formation of RNF168 and its downstream functional partners, such as 53BP1 and BRCA1, thus affecting the normal DNA damage repair process. PMID:23394999

  11. Mitochondrial DNA damage by bleomycin induces AML cell death.

    PubMed

    Yeung, ManTek; Hurren, Rose; Nemr, Carine; Wang, Xiaoming; Hershenfeld, Samantha; Gronda, Marcela; Liyanage, Sanduni; Wu, Yan; Augustine, Jeevan; Lee, Eric A; Spagnuolo, Paul A; Southall, Noel; Chen, Catherine; Zheng, Wei; Jeyaraju, Danny V; Minden, Mark D; Laposa, Rebecca; Schimmer, Aaron D

    2015-06-01

    Mitochondria contain multiple copies of their own 16.6 kb circular genome. To explore the impact of mitochondrial DNA (mtDNA) damage on mitochondrial (mt) function and viability of AML cells, we screened a panel of DNA damaging chemotherapeutic agents to identify drugs that could damage mtDNA. We identified bleomycin as an agent that damaged mtDNA in AML cells at concentrations that induced cell death. Bleomycin also induced mtDNA damage in primary AML samples. Consistent with the observed mtDNA damage, bleomycin reduced mt mass and basal oxygen consumption in AML cells. We also demonstrated that the observed mtDNA damage was functionally important for bleomycin-induced cell death. Finally, bleomycin delayed tumor growth in xenograft mouse models of AML and anti-leukemic concentrations of the drug induced mtDNA damage in AML cells preferentially over normal lung tissue. Taken together, mtDNA-targeted therapy may be an effective strategy to target AML cells and bleomycin could be useful in the treatment of this disease.

  12. Preventing Ultraviolet Light-Induced Damage: The Benefits of Antioxidants

    ERIC Educational Resources Information Center

    Yip, Cheng-Wai

    2007-01-01

    Extracts of fruit peels contain antioxidants that protect the bacterium "Escherichia coli" against damage induced by ultraviolet light. Antioxidants neutralise free radicals, thus preventing oxidative damage to cells and deoxyribonucleic acid. A high survival rate of UV-exposed cells was observed when grapefruit or grape peel extract was…

  13. Preventing Ultraviolet Light-Induced Damage: The Benefits of Antioxidants

    ERIC Educational Resources Information Center

    Yip, Cheng-Wai

    2007-01-01

    Extracts of fruit peels contain antioxidants that protect the bacterium "Escherichia coli" against damage induced by ultraviolet light. Antioxidants neutralise free radicals, thus preventing oxidative damage to cells and deoxyribonucleic acid. A high survival rate of UV-exposed cells was observed when grapefruit or grape peel extract was…

  14. Experimental studies on islets isolation, purification and function in rats.

    PubMed

    Pang, Xinlu; Xue, Wujun; Feng, Xinshun; Tian, Xiaohui; Teng, Yan; Ding, Xiaoming; Pan, Xiaoming; Guo, Qi; He, Xiaoli

    2015-01-01

    To develop a simple and effective method of islet isolation and purification in rats. Collagenase P was injected into pancreatic duct followed by incubation in water bath to digest the pancreas and isolate islet, then discontinuous gravity gradient purification was used to purify the islet. The purified islets were identified by dithizone staining. The viability of islets was assessed by fluorescence staining of acridine orange (AO) and propidium iodide (PI). The function of purified islets was determined by glucose-stimulated insulin release test and transplantation of rat with streptozocin-induced diabetes. 738±193 islets were recovered after purification. The average purity was 77±13%, the viability of islets was more than 95%. When inspected by glucose stimulation, the secreted insulin concentration was 24.31±5.47 mIU/L when stimulated by low concentration glucose and 37.62±4.29 mIU/L by high concentration glucose. There was significant difference between the two phases (P<0.05). The blood sugar concentration recovered to normal level after two days in the animals with islet transplantation. In conclusion, islets can be procured with good function and shape by using the method of injecting collagenase into pancreatic duct followed by incubation in water bath and purification using discontinuous gravity gradient.

  15. Experimental studies on islets isolation, purification and function in rats

    PubMed Central

    Pang, Xinlu; Xue, Wujun; Feng, Xinshun; Tian, Xiaohui; Teng, Yan; Ding, Xiaoming; Pan, Xiaoming; Guo, Qi; He, Xiaoli

    2015-01-01

    To develop a simple and effective method of islet isolation and purification in rats. Collagenase P was injected into pancreatic duct followed by incubation in water bath to digest the pancreas and isolate islet, then discontinuous gravity gradient purification was used to purify the islet. The purified islets were identified by dithizone staining. The viability of islets was assessed by fluorescence staining of acridine orange (AO) and propidium iodide (PI). The function of purified islets was determined by glucose-stimulated insulin release test and transplantation of rat with streptozocin-induced diabetes. 738±193 islets were recovered after purification. The average purity was 77±13%, the viability of islets was more than 95%. When inspected by glucose stimulation, the secreted insulin concentration was 24.31±5.47 mIU/L when stimulated by low concentration glucose and 37.62±4.29 mIU/L by high concentration glucose. There was significant difference between the two phases (P<0.05). The blood sugar concentration recovered to normal level after two days in the animals with islet transplantation. In conclusion, islets can be procured with good function and shape by using the method of injecting collagenase into pancreatic duct followed by incubation in water bath and purification using discontinuous gravity gradient. PMID:26885021

  16. Quercitrin protects skin from UVB-induced oxidative damage

    SciTech Connect

    Yin, Yuanqin; Li, Wenqi; Son, Young-Ok; Sun, Lijuan; Lu, Jian; Kim, Donghern; Wang, Xin; Yao, Hua; Wang, Lei; Pratheeshkumar, Poyil; Hitron, Andrew J.; Luo, Jia; Gao, Ning; Shi, Xianglin; Zhang, Zhuo

    2013-06-01

    Exposure of the skin to ultraviolet B (UVB) radiation causes oxidative damage to skin, resulting in sunburn, photoaging, and skin cancer. It is generally believed that the skin damage induced by UV irradiation is a consequence of generation of reactive oxygen species (ROS). Recently, there is an increased interest in the use of natural products as chemopreventive agents for non-melanoma skin cancer (NMSC) due to their antioxidants and anti-inflammatory properties. Quercitrin, glycosylated form of quercetin, is the most common flavonoid in nature with antioxidant properties. The present study investigated the possible beneficial effects of quercitrin to inhibit UVB irradiation-induced oxidative damage in vitro and in vivo. Our results showed that quercitrin decreased ROS generation induced by UVB irradiation in JB6 cells. Quercitrin restored catalase expression and GSH/GSSG ratio reduced by UVB exposure, two major antioxidant enzymes, leading to reductions of oxidative DNA damage and apoptosis and protection of the skin from inflammation caused by UVB exposure. The present study demonstrated that quercitrin functions as an antioxidant against UVB irradiation-induced oxidative damage to skin. - Highlights: • Oxidative stress plays a key role in UV-induced cell and tissue injuries. • Quercitrin decreases ROS generation and restores antioxidants irradiated by UVB. • Quercitrin reduces UVB-irradiated oxidative DNA damage, apoptosis, and inflammation. • Quercitrin functions as an antioxidant against UVB-induced skin injuries.

  17. Photoexcited riboflavin induces oxidative damage to human serum albumin

    NASA Astrophysics Data System (ADS)

    Hirakawa, Kazutaka; Yoshioka, Takuto

    2015-08-01

    Photoexcited riboflavin induced damage of human serum albumin (HSA), a water soluble protein, resulting in the diminishment of fluorescence from the tryptophan residue. Because riboflavin hardly photosensitized singlet oxygen generation and sodium azide, a singlet oxygen quencher, did not inhibit protein damage, electron transfer-mediated oxidation of HSA was speculated. Fluorescence lifetime of riboflavin was not affected by HSA, suggesting that the excited triplet state of riboflavin is responsible for protein damage through electron transfer. In addition, the preventive effect of xanthone derivatives, triplet quenchers, on photosensitized protein damage could be evaluated using this photosensitized reaction system of riboflavin and HSA.

  18. PWR fuel features to preclude externally induced damage

    SciTech Connect

    Shallenberger, J.M.; Wilson, J.F.; Knott, R.P.

    1987-01-01

    Over the past several years there have been instances of pressurized water reactor (PWR) fuel damage attributed to factors external to the fuel. These externally induced causes include debris in the reactor coolant and baffle jetting. These causes of PWR fuel damage account for --50% of the total number of damaged rods. This paper discusses two features that significantly reduce the potential for fuel damage due to debris and baffle jetting. These two features are the debris filter bottom nozzle (DFBN) and the antivibration clip.

  19. JANEX-1, a JAK3 inhibitor, protects pancreatic islets from cytokine toxicity through downregulation of NF-{kappa}B activation and the JAK/STAT pathway

    SciTech Connect

    Lv, Na; Kim, Eun-Kyung; Song, Mi-Young; Choi, Ha-Na; Moon, Woo Sung; Park, Sung-Joo; Park, Jin-Woo; Kwon, Kang-Beom; Park, Byung-Hyun

    2009-07-15

    JANEX-1/WHI-P131, a selective Janus kinase 3 (JAK3) inhibitor, has been shown to delay the onset of diabetes in the NOD mouse model. However, the molecular mechanism by which JANEX-1 protects pancreatic {beta}-cells is unknown. In the current study, we investigated the role of JANEX-1 on interleukin (IL)-1{beta} and interferon (IFN)-{gamma}-induced {beta}-cell damage using isolated islets. JANEX-1-pretreated islets showed resistance to cytokine toxicity, namely suppressed nitric oxide (NO) production, reduced inducible form of NO synthase (iNOS) expression, and decreased islet destruction. The molecular mechanism by which JANEX-1 inhibits iNOS expression was mediated through suppression of the nuclear factor {kappa}B (NF-{kappa}B) and JAK/signal transducer and activator of transcription (STAT) pathways. Islets treated with the cytokines downregulated the protein levels of suppressor of cytokine signaling (SOCS)-1 and SOCS-3, but pretreatment with JANEX-1 attenuated these decreases. Additionally, islets from JAK3{sup -/-} mice were more resistant to cytokine toxicity than islets from control mice. These results demonstrate that JANEX-1 protects {beta}-cells from cytokine toxicity through suppression of the NF-{kappa}B and JAK/STAT pathways and upregulation of SOCS proteins, suggesting that JANEX-1 may be used to preserve functional {beta}-cell mass.

  20. DNA damage in cells exhibiting radiation-induced genomic instability

    SciTech Connect

    Keszenman, Deborah J.; Kolodiuk, Lucia; Baulch, Janet E.

    2015-02-22

    Cells exhibiting radiation induced genomic instability exhibit varied spectra of genetic and chromosomal aberrations. Even so, oxidative stress remains a common theme in the initiation and/or perpetuation of this phenomenon. Isolated oxidatively modified bases, abasic sites, DNA single strand breaks and clustered DNA damage are induced in normal mammalian cultured cells and tissues due to endogenous reactive oxygen species generated during normal cellular metabolism in an aerobic environment. While sparse DNA damage may be easily repaired, clustered DNA damage may lead to persistent cytotoxic or mutagenic events that can lead to genomic instability. In this study, we tested the hypothesis that DNA damage signatures characterised by altered levels of endogenous, potentially mutagenic, types of DNA damage and chromosomal breakage are related to radiation-induced genomic instability and persistent oxidative stress phenotypes observed in the chromosomally unstable progeny of irradiated cells. The measurement of oxypurine, oxypyrimidine and abasic site endogenous DNA damage showed differences in non-double-strand breaks (DSB) clusters among the three of the four unstable clones evaluated as compared to genomically stable clones and the parental cell line. These three unstable clones also had increased levels of DSB clusters. The results of this study demonstrate that each unstable cell line has a unique spectrum of persistent damage and lead us to speculate that alterations in DNA damage signaling and repair may be related to the perpetuation of genomic instability.

  1. DNA damage in cells exhibiting radiation-induced genomic instability

    DOE PAGES

    Keszenman, Deborah J.; Kolodiuk, Lucia; Baulch, Janet E.

    2015-02-22

    Cells exhibiting radiation induced genomic instability exhibit varied spectra of genetic and chromosomal aberrations. Even so, oxidative stress remains a common theme in the initiation and/or perpetuation of this phenomenon. Isolated oxidatively modified bases, abasic sites, DNA single strand breaks and clustered DNA damage are induced in normal mammalian cultured cells and tissues due to endogenous reactive oxygen species generated during normal cellular metabolism in an aerobic environment. While sparse DNA damage may be easily repaired, clustered DNA damage may lead to persistent cytotoxic or mutagenic events that can lead to genomic instability. In this study, we tested the hypothesismore » that DNA damage signatures characterised by altered levels of endogenous, potentially mutagenic, types of DNA damage and chromosomal breakage are related to radiation-induced genomic instability and persistent oxidative stress phenotypes observed in the chromosomally unstable progeny of irradiated cells. The measurement of oxypurine, oxypyrimidine and abasic site endogenous DNA damage showed differences in non-double-strand breaks (DSB) clusters among the three of the four unstable clones evaluated as compared to genomically stable clones and the parental cell line. These three unstable clones also had increased levels of DSB clusters. The results of this study demonstrate that each unstable cell line has a unique spectrum of persistent damage and lead us to speculate that alterations in DNA damage signaling and repair may be related to the perpetuation of genomic instability.« less

  2. Characterization of a novel functional protein in the pancreatic islet: islet homeostasis protein regulation of glucagon synthesis in α cells.

    PubMed

    Oh, Seh-Hoon; Darwiche, Houda; Cho, Jae-Hyoung; Shupe, Thomas; Petersen, Bryon E

    2012-01-01

    We have identified a novel protein in bone marrow-derived insulin-producing cells. Here we characterize this protein, hereby named islet homeostasis protein (IHoP), in the pancreatic islet. Detection of IHoP mRNA and protein was performed using reverse transcriptase-polymerase chain reaction, immunocytochemistry, and in situ hybridization. Islet homeostasis protein functions were utilizing proliferation, insulin secretion by in vitro assays, and following small interfering RNA protocols for suppression of IHoP. We found that IHoP did not homolog with known pancreatic hormones. Islet homeostasis protein expression was seen in both bone marrow-derived insulin-producing cells and isolated pancreatic islets. Immunohistochemistry on pancreatic islet revealed that IHoP localized to the glucagon-synthesizing α cells. Inhibition of IHoP by small interfering RNA resulted in the loss of glucagon expression, which induced low blood glucose levels (63-85 mg/dL). Subsequently, cellular apoptosis was observed throughout the islet, including the insulin-producing β cells. Islets of preonset diabetic patients showed normal expression of IHoP and glucagon; however, IHoP was lost upon onset of the disease. These data suggest that IHoP could be a new functional protein in the islet and may play a role in islet homeostasis.

  3. A Method for Performing Islet Transplantation Using Tissue-Engineered Sheets of Islets and Mesenchymal Stem Cells

    PubMed Central

    Hirabaru, Masataka; Kuroki, Tamotsu; Adachi, Tomohiko; Kitasato, Amane; Ono, Shinichiro; Tanaka, Takayuki; Matsushima, Hajime; Sakai, Yusuke; Soyama, Akihiko; Hidaka, Masaaki; Yamanouchi, Kosho; Takatsuki, Mitsuhisa; Okano, Teruo

    2015-01-01

    Mesenchymal stem cells (MSCs) are known to have a protective effect on islet cells. Cell sheets developed using tissue engineering help maintain the function of the cells themselves. This study describes a tissue engineering approach using islets with MSC sheets to improve the therapeutic effect of islet transplantation. MSCs were obtained from Fischer 344 rats and engineered into cell sheets using temperature-responsive culture dishes. The islets obtained from Fischer 344 rats were seeded onto MSC sheets, and the islets with MSC sheets were harvested by low-temperature treatment after coculture. The functional activity of the islets with MSC sheets was confirmed by a histological examination, insulin secretion assay, and quantification of the levels of cytokines. The therapeutic effects of the islets with MSC sheets were investigated by transplanting the sheets at subcutaneous sites in severe combined immunodeficiency (SCID) mice with streptozotocin-induced diabetes. Improvement of islet function and viability was shown in situ on the MSC sheet, and the histological examination showed that the MSC sheet maintained adhesion factor on the surface. In the recipient mice, normoglycemia was maintained for at least 84 days after transplantation, and neovascularization was observed. These results demonstrated that islet transplantation in a subcutaneous site would be possible by using the MSC sheet as a scaffold for islets. PMID:26066973

  4. Growth factor protection against cytokine-induced apoptosis in neonatal rat islets of Langerhans: role of Fas.

    PubMed

    Harrison, M; Dunger, A M; Berg, S; Mabley, J; John, N; Green, M H; Green, I C

    1998-09-18

    Treatment of neonatal rat islets of Langerhans with combined cytokines (interleukin-1beta 10(-10) M, tumour necrosis factor-alpha 10(-10) M, interferon-gamma 5 U/ml) led to extensive cell death, which was potentiated by Fas activation with the anti-Fas cytolytic antibody JO2. Pre-treatment with insulin (25 ng/ml) or insulin-like growth factor-1 (10(-8)M) gave only partial protection against cell killing, but prevented the Fas-mediated component. In the absence of cytokine treatment, Fas-mediated killing was not observed.

  5. Modelling low velocity impact induced damage in composite laminates

    NASA Astrophysics Data System (ADS)

    Shi, Yu; Soutis, Constantinos

    2017-12-01

    The paper presents recent progress on modelling low velocity impact induced damage in fibre reinforced composite laminates. It is important to understand the mechanisms of barely visible impact damage (BVID) and how it affects structural performance. To reduce labour intensive testing, the development of finite element (FE) techniques for simulating impact damage becomes essential and recent effort by the composites research community is reviewed in this work. The FE predicted damage initiation and propagation can be validated by Non Destructive Techniques (NDT) that gives confidence to the developed numerical damage models. A reliable damage simulation can assist the design process to optimise laminate configurations, reduce weight and improve performance of components and structures used in aircraft construction.

  6. Femtosecond laser induced damage of pulse compression gratings

    NASA Astrophysics Data System (ADS)

    Kong, Fanyu; Huang, Haopeng; Wang, Leilei; Shao, Jianda; Jin, Yunxia; Xia, Zhilin; Chen, Junming; Li, Linxin

    2017-12-01

    Laser induced damage of Au-coated gratings (ACG) and metal multilayer dielectric gratings (MMDG) for pulse compression were measured using 800 ± 35 nm femto-laser with pulse width of 30.2 fs. The -1st order diffraction efficiency of the ACG is over 90% in wavelength range from 700 to 1000 nm. The MMDG has a 148 nm bandwidth (750-897 nm) with -1st order diffraction efficiency greater than 90%. The laser damage experiment on grating samples was performed in air for single-shot damage. The single-shot damage threshold of the ACG and MMDG was determined to be 0.32 ± 0.02 J/cm2 and 0.31 ± 0.02 J/cm2, respectively. The damage morphologies of the ACG revealed that the damage was attributed to the pinholes at the base of the grating pillars and the weak adhesion between metal layer and photoresist gratings layer. The damage feature combined with near field distribution of MMDG indicated that the damage was due to the nonlinear ionization process of the valence electrons in HfO2 film. According to analysis results, the laser damage resistance of the ACG can be enhanced through avoiding the appearance of pinholes and increasing adhesion between metal layer and photoresist layer. And for the MMDG, good performance of HfO2 film, low near field enhancement and single HfO2 grating structures may increase its laser damage resistance.

  7. Distinct differences in the responses of the human pancreatic β-cell line EndoC-βH1 and human islets to proinflammatory cytokines

    PubMed Central

    Oleson, Bryndon J.; McGraw, Jennifer A.; Broniowska, Katarzyna A.; Annamalai, Mani; Chen, Jing; Bushkofsky, Justin R.; Davis, Dawn B.; Mathews, Clayton E.

    2015-01-01

    While insulinoma cells have been developed and proven to be extremely useful in studies focused on mechanisms controlling β-cell function and viability, translating findings to human β-cells has proven difficult because of the limited access to human islets and the absence of suitable insulinoma cell lines of human origin. Recently, a human β-cell line, EndoC-βH1, has been derived from human fetal pancreatic buds. The purpose of this study was to determine whether human EndoC-βH1 cells respond to cytokines in a fashion comparable to human islets. Unlike most rodent-derived insulinoma cell lines that respond to cytokines in a manner consistent with rodent islets, EndoC-βH1 cells fail to respond to a combination of cytokines (IL-1, IFN-γ, and TNF) in a manner consistent with human islets. Nitric oxide, produced following inducible nitric oxide synthase (iNOS) expression, is a major mediator of cytokine-induced human islet cell damage. We show that EndoC-βH1 cells fail to express iNOS or produce nitric oxide in response to this combination of cytokines. Inhibitors of iNOS prevent cytokine-induced loss of human islet cell viability; however, they do not prevent cytokine-induced EndoC-βH1 cell death. Stressed human islets or human islets expressing heat shock protein 70 (HSP70) are resistant to cytokines, and, much like stressed human islets, EndoC-βH1 cells express HSP70 under basal conditions. Elevated basal expression of HSP70 in EndoC-βH1 cells is consistent with the lack of iNOS expression in response to cytokine treatment. While expressing HSP70, EndoC-βH1 cells fail to respond to endoplasmic reticulum stress activators, such as thapsigargin. These findings indicate that EndoC-βH1 cells do not faithfully recapitulate the response of human islets to cytokines. Therefore, caution should be exercised when making conclusions regarding the actions of cytokines on human islets when using this human-derived insulinoma cell line. PMID:26084699

  8. Distinct differences in the responses of the human pancreatic β-cell line EndoC-βH1 and human islets to proinflammatory cytokines.

    PubMed

    Oleson, Bryndon J; McGraw, Jennifer A; Broniowska, Katarzyna A; Annamalai, Mani; Chen, Jing; Bushkofsky, Justin R; Davis, Dawn B; Corbett, John A; Mathews, Clayton E

    2015-09-01

    While insulinoma cells have been developed and proven to be extremely useful in studies focused on mechanisms controlling β-cell function and viability, translating findings to human β-cells has proven difficult because of the limited access to human islets and the absence of suitable insulinoma cell lines of human origin. Recently, a human β-cell line, EndoC-βH1, has been derived from human fetal pancreatic buds. The purpose of this study was to determine whether human EndoC-βH1 cells respond to cytokines in a fashion comparable to human islets. Unlike most rodent-derived insulinoma cell lines that respond to cytokines in a manner consistent with rodent islets, EndoC-βH1 cells fail to respond to a combination of cytokines (IL-1, IFN-γ, and TNF) in a manner consistent with human islets. Nitric oxide, produced following inducible nitric oxide synthase (iNOS) expression, is a major mediator of cytokine-induced human islet cell damage. We show that EndoC-βH1 cells fail to express iNOS or produce nitric oxide in response to this combination of cytokines. Inhibitors of iNOS prevent cytokine-induced loss of human islet cell viability; however, they do not prevent cytokine-induced EndoC-βH1 cell death. Stressed human islets or human islets expressing heat shock protein 70 (HSP70) are resistant to cytokines, and, much like stressed human islets, EndoC-βH1 cells express HSP70 under basal conditions. Elevated basal expression of HSP70 in EndoC-βH1 cells is consistent with the lack of iNOS expression in response to cytokine treatment. While expressing HSP70, EndoC-βH1 cells fail to respond to endoplasmic reticulum stress activators, such as thapsigargin. These findings indicate that EndoC-βH1 cells do not faithfully recapitulate the response of human islets to cytokines. Therefore, caution should be exercised when making conclusions regarding the actions of cytokines on human islets when using this human-derived insulinoma cell line.

  9. Vitamin D3 restores altered cholinergic and insulin receptor expression in the cerebral cortex and muscarinic M3 receptor expression in pancreatic islets of streptozotocin induced diabetic rats.

    PubMed

    Kumar, Peeyush T; Antony, Sherin; Nandhu, Mohan S; Sadanandan, Jayanarayanan; Naijil, George; Paulose, Chiramadathikudiyil S

    2011-05-01

    Nutritional therapy is a challenging but necessary dimension in the management of diabetes and neurodegenerative changes associated with it. The study evaluates the effect of vitamin D(3) in preventing the altered function of cholinergic, insulin receptors and GLUT3 in the cerebral cortex of diabetic rats. Muscarinic M3 acetylcholine receptors in pancreas control insulin secretion. Vitamin D(3) treatment in M3 receptor regulation in the pancreatic islets was also studied. Radioreceptor binding assays and gene expression was done in the cerebral cortex of male Wistar rats. Immunocytochemistry of muscarinic M3 receptor was studied in the pancreatic islets using specific antibodies. Y-maze was used to evaluate the exploratory and spatial memory. Diabetes induced a decrease in muscarinic M1, insulin and vitamin D receptor expression and an increase in muscarinic M3, α7 nicotinic acetylcholine receptor, acetylcholine esterase and GLUT3 expression. Vitamin D(3) and insulin treatment reversed diabetes-induced alterations to near control. Diabetic rats showed a decreased Y-maze performance while vitamin D(3) supplementation improved the behavioural deficit. In conclusion, vitamin D(3) shows a potential therapeutic effect in normalizing diabetes-induced alterations in cholinergic, insulin and vitamin D receptor and maintains a normal glucose transport and utilisation in the cortex. In addition vitamin D(3) modulated muscarinic M3 receptors activity in pancreas and plays a pivotal role in controlling insulin secretion. Hence our findings proved, vitamin D(3) supplementation as a potential nutritional therapy in ameliorating diabetes mediated cortical dysfunctions and suggest an interaction between vitamin D(3) and muscarinic M3 receptors in regulating insulin secretion from pancreas.

  10. Laser-Induced Thermal Damage of Skin

    DTIC Science & Technology

    1977-12-01

    Negro Skin . 17 7 Transmission Spectrum of Human Epidermis , . 18 8 Radial and Axial Grid Poinkts and Increments 29 9 CO2 Laser Setup and Resulcant Burns...of -•y of Chicago. Two-thirds of the predicted del ir- reversible damage were within one ) f the histological measurements of dama e 13 ro- duced by... NEGRO 1 0 - i - .-- - - --10VI SIBLE il L li . 0.2 0.4 0.6 0.8 1.0 2.0 4.C 6.0 8.0 10.0 20.0 40.0 WAVELENGTH, Um Figure 6. Spectral reflectance of white

  11. Chronic overproduction of islet amyloid polypeptide/amylin in transgenic mice: lysosomal localization of human islet amyloid polypeptide and lack of marked hyperglycaemia or hyperinsulinaemia.

    PubMed

    Höppener, J W; Verbeek, J S; de Koning, E J; Oosterwijk, C; van Hulst, K L; Visser-Vernooy, H J; Hofhuis, F M; van Gaalen, S; Berends, M J; Hackeng, W H

    1993-12-01

    Type 2 (non-insulin-dependent) diabetes mellitus is characterised by hyperglycaemia, peripheral insulin resistance, impaired insulin secretion and pancreatic islet amyloid formation. The major constituent of islet amyloid is islet amyloid polypeptide (amylin). Islet amyloid polypeptide is synthesized by islet beta cells and co-secreted with insulin. The ability of islet amyloid polypeptide to form amyloid fibrils is related to its species-specific amino acid sequence. Islet amyloid associated with diabetes is only found in man, monkeys, cats and racoons. Pharmacological doses of islet amyloid polypeptide have been shown to inhibit insulin secretion as well as insulin action on peripheral tissues (insulin resistance). To examine the role of islet amyloid polypeptide in the pathogenesis of Type 2 diabetes, we have generated transgenic mice with the gene encoding either human islet amyloid polypeptide (which can form amyloid) or rat islet amyloid polypeptide, under control of an insulin promoter. Transgenic islet amyloid polypeptide mRNA was detected in the pancreas in all transgenic mice. Plasma islet amyloid polypeptide levels were significantly elevated (up to 15-fold) in three out of five transgenic lines, but elevated glucose levels, hyperinsulinaemia and obesity were not observed. This suggests that insulin resistance is not induced by chronic hypersecretion of islet amyloid polypeptide. Islet amyloid polypeptide immunoreactivity was localized to beta-cell secretory granules in all mice. Islet amyloid polypeptide immunoreactivity in beta-cell lysosomes was seen only in mice with the human islet amyloid polypeptide gene, as in human beta cells, and might represent an initial step in intracellular formation of amyloid fibrils.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Transcriptional Regulation of the Pancreatic Islet: Implications for Islet Function

    PubMed Central

    Stitzel, Michael L.; Kycia, Ina; Kursawe, Romy; Ucar, Duygu

    2015-01-01

    Islets of Langerhans contain multiple hormone-producing endocrine cells controlling glucose homeostasis. Transcription establishes and maintains islet cellular fates and identities. Genetic and environmental disruption of islet transcription triggers cellular dysfunction and disease. Early transcriptional regulation studies of specific islet genes, including insulin (INS) and the transcription factor PDX1, identified the first cis-regulatory DNA sequences and trans-acting factors governing islet function. Here, we review how human islet “omics” studies are reshaping our understanding of transcriptional regulation in islet (dys)function and diabetes. First, we highlight the expansion of islet transcript number, form, and function and of DNA transcriptional regulatory elements controlling their production. Next, we cover islet transcriptional effects of genetic and environmental perturbation. Finally, we discuss how these studies’ emerging insights should empower our diabetes research community to build mechanistic understanding of diabetes pathophysiology and to equip clinicians with tailored, precision medicine options to prevent and treat islet dysfunction and diabetes. PMID:26272056

  13. New Treatment Strategies for Alcohol-Induced Heart Damage

    PubMed Central

    Fernández-Solà, Joaquim; Planavila Porta, Ana

    2016-01-01

    High-dose alcohol misuse induces multiple noxious cardiac effects, including myocyte hypertrophy and necrosis, interstitial fibrosis, decreased ventricular contraction and ventricle enlargement. These effects produce diastolic and systolic ventricular dysfunction leading to congestive heart failure, arrhythmias and an increased death rate. There are multiple, dose-dependent, synchronic and synergistic mechanisms of alcohol-induced cardiac damage. Ethanol alters membrane permeability and composition, interferes with receptors and intracellular transients, induces oxidative, metabolic and energy damage, decreases protein synthesis, excitation-contraction coupling and increases cell apoptosis. In addition, ethanol decreases myocyte protective and repair mechanisms and their regeneration. Although there are diverse different strategies to directly target alcohol-induced heart damage, they are partially effective, and can only be used as support medication in a multidisciplinary approach. Alcohol abstinence is the preferred goal, but control drinking is useful in alcohol-addicted subjects not able to abstain. Correction of nutrition, ionic and vitamin deficiencies and control of alcohol-related systemic organ damage are compulsory. Recently, several growth factors (myostatin, IGF-1, leptin, ghrelin, miRNA, and ROCK inhibitors) and new cardiomyokines such as FGF21 have been described to regulate cardiac plasticity and decrease cardiac damage, improving cardiac repair mechanisms, and they are promising agents in this field. New potential therapeutic targets aim to control oxidative damage, myocyte hypertrophy, interstitial fibrosis and persistent apoptosis In addition, stem-cell therapy may improve myocyte regeneration. However, these strategies are not yet approved for clinical use. PMID:27690014

  14. Physics associated with cavitation induced material damage

    NASA Technical Reports Server (NTRS)

    Peterson, F. B.

    1974-01-01

    The role of cavitation in mechanical failure is discussed. Some of the most common types of material damage associated with the presence of cavitation are surface material removal, delamination and structural vibration. This occurs in external flows such as on propellers, hydrofoils, and high speed non-lifting surfaces. In internal flows, pipe bends, inlets, constructions, pumps and turbines are typical. Nominally nonflowing liquids are also susceptible in, for example, strong acoustic fields and high energy particle detectors. For flowing systems, Bernoulli's equation shows how a local pressure is reduced as the fluid's velocity is increased. At sufficiently high velocities, a tension can actually develop and this has, in fact, been demonstrated experimentally. Once the pressure is reduced below the fluid vapor pressure a vapor cavity can be nucleated. Various aspects of this process are simply shown by considering the flow over a lifting surface.

  15. Hydroxyl radical Thymine adduct induced DNA damages

    NASA Astrophysics Data System (ADS)

    Schyman, Patric; Eriksson, Leif A.; Zhang, Ru bo; Laaksonen, Aatto

    2008-06-01

    DNA damages caused by a 5-hydroxy-5,6-dihydrothymine-6-yl radical (5-OHT-6yl) abstracting a C2‧ hydrogen from a neighboring sugar (inter-H abstraction) have been theoretically investigated using hybrid DFT in gas phase and in water solution. The inter-H abstraction was here shown to be comparable in energy (24 kcal mol-1) with the intra-H abstraction in which the 5-OHT-6yl abstracts a C2‧ hydrogen from its own sugar. The effect of a neutrally or a negatively charged phosphate group was also studied and the results show no significant impact on the activation energy of the hydrogen abstraction whereas base release and strand break reactions are affected.

  16. Physics associated with cavitation induced material damage

    NASA Technical Reports Server (NTRS)

    Peterson, F. B.

    1974-01-01

    The role of cavitation in mechanical failure is discussed. Some of the most common types of material damage associated with the presence of cavitation are surface material removal, delamination and structural vibration. This occurs in external flows such as on propellers, hydrofoils, and high speed non-lifting surfaces. In internal flows, pipe bends, inlets, constructions, pumps and turbines are typical. Nominally nonflowing liquids are also susceptible in, for example, strong acoustic fields and high energy particle detectors. For flowing systems, Bernoulli's equation shows how a local pressure is reduced as the fluid's velocity is increased. At sufficiently high velocities, a tension can actually develop and this has, in fact, been demonstrated experimentally. Once the pressure is reduced below the fluid vapor pressure a vapor cavity can be nucleated. Various aspects of this process are simply shown by considering the flow over a lifting surface.

  17. NK T cell-induced protection against diabetes in V alpha 14-J alpha 281 transgenic nonobese diabetic mice is associated with a Th2 shift circumscribed regionally to the islets and functionally to islet autoantigen.

    PubMed

    Laloux, V; Beaudoin, L; Jeske, D; Carnaud, C; Lehuen, A

    2001-03-15

    The onset of autoimmune diabetes is related to defective immune regulation. Recent studies have shown that NK T cells are deficient in number and function in both diabetic patients and nonobese diabetic (NOD) mice. NK T cells, which are CD1d restricted, express a TCR with an invariant V alpha 14-J alpha 281 chain and rapidly produce large amounts of cytokines. V alpha 14-J alpha 281 transgenic NOD mice have increased numbers of NK T cells and are protected against diabetes onset. In this study we analyzed where and how NK T cells interfere with the development of the anti-islet autoimmune response. NK T cells, which are usually rare in lymph nodes, are abundant in pancreatic lymph nodes and are also present in islets. IL-4 mRNA levels are increased and IFN-gamma mRNA levels decreased in islets from diabetes-free V alpha 14-J alpha 281 transgenic NOD mice; the IgG1/IgG2c ratio of autoantibodies against glutamic acid decarboxylase is also increased in these mice. Treatment with IL-12 (a pro-Th1 cytokine) or anti-IL-4 Ab abolishes the diabetes protection in V alpha 14-J alpha 281 NOD mice. The protection from diabetes conferred by NK T cells is thus associated with a Th2 shift within islets directed against autoantigen such as glutamic acid decarboxylase. Our findings also demonstrate the key role of IL-4.

  18. Polyphenol-Rich Extract of Syzygium cumini Leaf Dually Improves Peripheral Insulin Sensitivity and Pancreatic Islet Function in Monosodium L-Glutamate-Induced Obese Rats

    PubMed Central

    Sanches, Jonas R.; França, Lucas M.; Chagas, Vinicyus T.; Gaspar, Renato S.; dos Santos, Kayque A.; Gonçalves, Luciana M.; Sloboda, Deborah M.; Holloway, Alison C.; Dutra, Richard P.; Carneiro, Everardo M.; Cappelli, Ana Paula G.; Paes, Antonio Marcus de A.

    2016-01-01

    Syzygium cumini (L.) Skeels (Myrtaceae) has been traditionally used to treat a number of illnesses. Ethnopharmacological studies have particularly addressed antidiabetic and metabolic-related effects of extracts prepared from its different parts, especially seed, and pulp-fruit, however. there is a lack of studies on phytochemical profile and biological properties of its leaf. As there is considerable interest in bioactive compounds to treat metabolic syndrome and its clustered risk factors, we sought to characterize the metabolic effects of hydroethanolic extract of S. cumini leaf (HESc) on lean and monosodium L-glutamate (MSG)-induced obese rats. HPLC-MS/MS characterization of the HESc polyphenolic profile, at 254 nm, identified 15 compounds pertaining to hydrolysable tannin and flavanol subclasses. At 60 days of age, both groups were randomly assigned to receive HESc (500 mg/kg) or vehicle for 30 days. At the end of treatment, obese+HESc exhibited significantly lower body weight gain, body mass index, and white adipose tissue mass, compared to obese rats receiving vehicle. Obese rats treated with HESc showed a twofold increase in lipolytic activity in the periepididymal fat pad, as well as, brought triglyceride levels in serum, liver and skeletal muscle back to levels close those found in lean animals. Furthermore, HESc also improved hyperinsulinemia and insulin resistance in obese+HESc rats, which resulted in partial reversal of glucose intolerance, as compared to obese rats. HESc had no effect in lean rats. Assessment of ex vivo glucose-stimulated insulin secretion showed HESc potentiated pancreatic function in islets isolated from both lean and obese rats treated with HESc. In addition, HESc (10–1000 μg/mL) increased glucose stimulated insulin secretion from both isolated rat islets and INS-1E β-cells. These data demonstrate that S. cumini leaf improved peripheral insulin sensitivity via stimulating/modulating β-cell insulin release, which was associated

  19. Facet-Dependent Interactions of Islet Amyloid Polypeptide with Gold Nanoparticles: Implications for Fibril Formation and Peptide-Induced Lipid Membrane Disruption

    PubMed Central

    2017-01-01

    A comprehensive understanding of the mechanisms of interaction between proteins or peptides and nanomaterials is crucial for the development of nanomaterial-based diagnostics and therapeutics. In this work, we systematically explored the interactions between citrate-capped gold nanoparticles (AuNPs) and islet amyloid polypeptide (IAPP), a 37-amino acid peptide hormone co-secreted with insulin from the pancreatic islet. We utilized diffusion-ordered spectroscopy, isothermal titration calorimetry, localized surface plasmon resonance spectroscopy, gel electrophoresis, atomic force microscopy, transmission electron microscopy (TEM), and molecular dynamics (MD) simulations to systematically elucidate the underlying mechanism of the IAPP–AuNP interactions. Because of the presence of a metal-binding sequence motif in the hydrophilic peptide domain, IAPP strongly interacts with the Au surface in both the monomeric and fibrillar states. Circular dichroism showed that AuNPs triggered the IAPP conformational transition from random coil to ordered structures (α-helix and β-sheet), and TEM imaging suggested the acceleration of IAPP fibrillation in the presence of AuNPs. MD simulations revealed that the IAPP–AuNP interactions were initiated by the N-terminal domain (IAPP residues 1–19), which subsequently induced a facet-dependent conformational change in IAPP. On a Au(111) surface, IAPP was unfolded and adsorbed directly onto the Au surface, while for the Au(100) surface, it interacted predominantly with the citrate adlayer and retained some helical conformation. The observed affinity of AuNPs for IAPP was further applied to reduce the level of peptide-induced lipid membrane disruption. PMID:28260837

  20. Polyphenol-Rich Extract of Syzygium cumini Leaf Dually Improves Peripheral Insulin Sensitivity and Pancreatic Islet Function in Monosodium L-Glutamate-Induced Obese Rats.

    PubMed

    Sanches, Jonas R; França, Lucas M; Chagas, Vinicyus T; Gaspar, Renato S; Dos Santos, Kayque A; Gonçalves, Luciana M; Sloboda, Deborah M; Holloway, Alison C; Dutra, Richard P; Carneiro, Everardo M; Cappelli, Ana Paula G; Paes, Antonio Marcus de A

    2016-01-01

    Syzygium cumini (L.) Skeels (Myrtaceae) has been traditionally used to treat a number of illnesses. Ethnopharmacological studies have particularly addressed antidiabetic and metabolic-related effects of extracts prepared from its different parts, especially seed, and pulp-fruit, however. there is a lack of studies on phytochemical profile and biological properties of its leaf. As there is considerable interest in bioactive compounds to treat metabolic syndrome and its clustered risk factors, we sought to characterize the metabolic effects of hydroethanolic extract of S. cumini leaf (HESc) on lean and monosodium L-glutamate (MSG)-induced obese rats. HPLC-MS/MS characterization of the HESc polyphenolic profile, at 254 nm, identified 15 compounds pertaining to hydrolysable tannin and flavanol subclasses. At 60 days of age, both groups were randomly assigned to receive HESc (500 mg/kg) or vehicle for 30 days. At the end of treatment, obese+HESc exhibited significantly lower body weight gain, body mass index, and white adipose tissue mass, compared to obese rats receiving vehicle. Obese rats treated with HESc showed a twofold increase in lipolytic activity in the periepididymal fat pad, as well as, brought triglyceride levels in serum, liver and skeletal muscle back to levels close those found in lean animals. Furthermore, HESc also improved hyperinsulinemia and insulin resistance in obese+HESc rats, which resulted in partial reversal of glucose intolerance, as compared to obese rats. HESc had no effect in lean rats. Assessment of ex vivo glucose-stimulated insulin secretion showed HESc potentiated pancreatic function in islets isolated from both lean and obese rats treated with HESc. In addition, HESc (10-1000 μg/mL) increased glucose stimulated insulin secretion from both isolated rat islets and INS-1E β-cells. These data demonstrate that S. cumini leaf improved peripheral insulin sensitivity via stimulating/modulating β-cell insulin release, which was associated

  1. BACE2 suppression promotes β-cell survival and function in a model of type 2 diabetes induced by human islet amyloid polypeptide overexpression.

    PubMed

    Alcarraz-Vizán, Gema; Castaño, Carlos; Visa, Montse; Montane, Joel; Servitja, Joan-Marc; Novials, Anna

    2017-03-23

    BACE2 (β-site APP-cleaving enzyme 2) is a protease expressed in the brain, but also in the pancreas, where it seems to play a physiological role. Amyloidogenic diseases, including Alzheimer's disease and type 2 diabetes (T2D), share the accumulation of abnormally folded and insoluble proteins that interfere with cell function. In T2D, islet amyloid polypeptide (IAPP) deposits have been shown to be a pathogenic key feature of the disease. The aim of the present study was to investigate the effect of BACE2 modulation on β-cell alterations in a mouse model of T2D induced by IAPP overexpression. Heterozygous mice carrying the human transcript of IAPP (hIAPP-Tg) were used as a model to study the deleterious effects of IAPP upon β-cell function. These animals showed glucose intolerance and impaired insulin secretion. When crossed with BACE2-deficient mice, the animals presented a significant improvement in glucose tolerance accompanied with an enhanced insulin secretion, as compared to hIAPP-Tg mice. BACE2 deficiency also partially reverted gene expression changes observed in islets from hIAPP-Tg mice, including a set of genes related to inflammation. Moreover, homozygous hIAPP mice presented a severe hyperglycemia and a high lethality rate from 8 weeks onwards due to a massive destruction of β-cell mass. This process was significantly reduced when crossed with the BACE2-KO model, improving the survival rate of the animals. Altogether, the absence of BACE2 ameliorates glucose tolerance defects induced by IAPP overexpression in the β-cell and promotes β-cell survival. Thus, targeting BACE2 may represent a promising therapeutic strategy to improve β-cell function in T2D.

  2. Redox Signal-mediated Enhancement of the Temperature Sensitivity of Transient Receptor Potential Melastatin 2 (TRPM2) Elevates Glucose-induced Insulin Secretion from Pancreatic Islets.

    PubMed

    Kashio, Makiko; Tominaga, Makoto

    2015-05-08

    Transient receptor potential melastatin 2 (TRPM2) is a thermosensitive Ca(2+)-permeable cation channel expressed by pancreatic β cells where channel function is constantly affected by body temperature. We focused on the physiological functions of redox signal-mediated TRPM2 activity at body temperature. H2O2, an important molecule in redox signaling, reduced the temperature threshold for TRPM2 activation in pancreatic β cells of WT mice but not in TRPM2KO cells. TRPM2-mediated [Ca(2+)]i increases were likely caused by Ca(2+) influx through the plasma membrane because the responses were abolished in the absence of extracellular Ca(2+). In addition, TRPM2 activation downstream from the redox signal plus glucose stimulation enhanced glucose-induced insulin secretion. H2O2 application at 37 °C induced [Ca(2+)]i increases not only in WT but also in TRPM2KO β cells. This was likely due to the effect of H2O2 on KATP channel activity. However, the N-acetylcysteine-sensitive fraction of insulin secretion by WT islets was increased by temperature elevation, and this temperature-dependent enhancement was diminished significantly in TRPM2KO islets. These data suggest that endogenous redox signals in pancreatic β cells elevate insulin secretion via TRPM2 sensitization and activity at body temperature. The results in this study could provide new therapeutic approaches for the regulation of diabetic conditions by focusing on the physiological function of TRPM2 and redox signals. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Heavy ion induced permanent damage in MNOS gate insulators

    NASA Astrophysics Data System (ADS)

    Pickel, J. C.; Blandford, J. T., Jr.; Waskiewicz, A. E.; Strahan, V. H., Jr.

    1985-12-01

    Heavy-ion-induced permanent damage in MNOS gate insulators has been investigated using a Cf252 fission source. The electric field and ion LET thresholds for onset of the damage has been characterized. The results are consistent with a thermal runaway mechanism in the silicon nitride layer initiated by a single heavy ion and leading to a permanent high conductivity path through the dielectric layers.

  4. Tyrosine-dependent oxidative DNA damage induced by carcinogenic tetranitromethane.

    PubMed

    Murata, Mariko; Kurimoto, Saori; Kawanishi, Shosuke

    2006-10-01

    Tetranitromethane (TNM) is used as an oxidizer in rocket propellants and explosives and as an additive to increase the cetane number of diesel fuel. TNM was reported to induce pulmonary adenocarcinomas and squamous cell carcinomas in mice and rats. However, the mechanisms underlying carcinogenesis induced by TNM has not yet been clarified. We previously revealed that nitroTyr and nitroTyr-containing peptides caused Cu(II)-dependent DNA damage in the presence of P450 reductase, which is considered to yield nitroreduction. Since TNM is a reagent for nitration of Tyr in proteins and peptides, we have hypothesized that TNM-treated Tyr and Tyr-containing peptides induce DNA damage by the modification of Tyr. We examined DNA damage induced by TNM-treated amino acids or peptides using (32)P-5'-end-labeled DNA fragments obtained from the human p53 tumor suppressor gene and the c-Ha-ras-1 protooncogene. TNM-treated Tyr and Lys-Tyr-Lys induced DNA damage including the formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine in the presence of Cu(II) and NADH. DNA damage was inhibited by catalase and bathocuproine, indicating the involvement of H(2)O(2) and Cu(I). The cytosine residue of the ACG sequence complementary to codon 273, well-known hotspots of the p53 gene, was cleaved with piperidine and Fpg treatments. On the other hand, nitroTyr and Lys-nitroTyr-Lys did not induce DNA damage in the presence of Cu(II) and NADH. Time-of-flight mass spectrometry confirmed that reactions between Lys-Tyr-Lys and TNM yielded not only Lys-nitroTyr-Lys but also Lys-nitrosoTyr-Lys. Therefore, it is speculated that the nitrosotyrosine residue can induce oxidative DNA damage in the presence of Cu(II) and NADH. It is concluded that Tyr-dependent DNA damage may play an important role in the carcinogenicity of TNM. TNM is a new type of carcinogen that induces DNA damage not by itself but via Tyr modification.

  5. Sulforaphane protects against cytokine- and streptozotocin-induced {beta}-cell damage by suppressing the NF-{kappa}B pathway

    SciTech Connect

    Song, Mi-Young; Kim, Eun-Kyung; Moon, Woo-Sung; Park, Jin-Woo; Kim, Hyung-Jin; So, Hong-Seob; Park, Raekil; Kwon, Kang-Beom Park, Byung-Hyun

    2009-02-15

    Sulforaphane (SFN) is an indirect antioxidant that protects animal tissues from chemical or biological insults by stimulating the expression of several NF-E2-related factor-2 (Nrf2)-regulated phase 2 enzymes. Treatment of RINm5F insulinoma cells with SFN increases Nrf2 nuclear translocation and expression of phase 2 enzymes. In this study, we investigated whether the activation of Nrf2 by SFN treatment or ectopic overexpression of Nrf2 inhibited cytokine-induced {beta}-cell damage. Treatment of RIN cells with IL-1{beta} and IFN-{gamma} induced {beta}-cell damage through a NF-{kappa}B-dependent signaling pathway. Activation of Nrf2 by treatment with SFN and induction of Nrf2 overexpression by transfection with Nrf2 prevented cytokine toxicity. The mechanism by which Nrf2 activation inhibited NF-{kappa}B-dependent cell death signals appeared to involve the reduction of oxidative stress, as demonstrated by the inhibition of cytokine-induced H{sub 2}O{sub 2} production. The protective effect of SFN was further demonstrated by the restoration of normal insulin secreting responses to glucose in cytokine-treated rat pancreatic islets. Furthermore, pretreatment with SFN blocked the development of type 1 diabetes in streptozotocin-treated mice.

  6. Inducible repair of oxidative DNA damage in Escherichia coli.

    PubMed

    Demple, B; Halbrook, J

    Hydrogen peroxide is lethal to many cell types, including the bacterium Escherichia coli. Peroxides yield transient radical species that can damage DNA and cause mutations. Such partially reduced oxygen species are occasionally released during cellular respiration and are generated by lethal and mutagenic ionizing radiation. Because cells live in an environment where the threat of oxidative DNA damage is continual, cellular mechanisms may have evolved to avoid and repair this damage. Enzymes are known which evidently perform these functions. We report here that resistance to hydrogen peroxide toxicity can be induced in E. coli, that this novel induction is specific and occurs, in part, at the level of DNA repair.

  7. Islet transplantation: immunological perspectives.

    PubMed

    Inverardi, Luca; Kenyon, Norma S; Ricordi, Camillo

    2003-10-01

    Clinical trials of islet transplantation are showing remarkable success, but they require administration of chronic immunosuppression, and are underscoring the large gap that exists between the number of human donors available and the number of patients that could benefit from the procedure. Recent progress has been made in the definition of key immunological mechanisms that are involved in determining islet transplant outcome. Clinical and preclinical studies, and studies in small animal model systems, will all eventually contribute to the definition of efficient and safe protocols for islet transplantation. If the use of xenografts is successful, it might represent a solution to the shortage of human organs.

  8. Modeling of Laser Induced Damage in NIF UV Optics

    SciTech Connect

    Feit, M D; Rubenchik, A M

    2001-02-21

    Controlling damage to nominally transparent optical elements such as lenses, windows and frequency conversion crystals on high power lasers is a continuing technical problem. Scientific understanding of the underlying mechanisms of laser energy absorption, material heating and vaporization and resultant mechanical damage is especially important for UV lasers with large apertures such as NIF. This LDRD project was a single year effort, in coordination with associated experimental projects, to initiate theoretical descriptions of several of the relevant processes. In understanding laser damage, we distinguish between damage initiation and the growth of existent damage upon subsequent laser irradiation. In general, the effect of damage could be ameliorated by either preventing its initiation or by mitigating its growth. The distinction comes about because initiation is generally due to extrinsic factors such as contaminants, which provide a means of local laser energy absorption. Thus, initiation tends to be local and stochastic in nature. On the other hand, the initial damaging event appears to modify the surrounding material in such a way that multiple pulse damage grows more or less regularly. More exactly, three ingredients are necessary for visible laser induced damage. These are adequate laser energy, a mechanism of laser energy absorption and mechanical weakness. For damage growth, the material surrounding a damage site is already mechanically weakened by cracks and probably chemically modified as well. The mechanical damage can also lead to electric field intensification due to interference effects, thus increasing the available laser energy density. In this project, we successfully accounted for the pulselength dependence of damage threshold in bulk DKDP crystals with the hypothesis of small absorbers with a distribution of sizes. We theoretically investigated expected scaling of damage initiation craters both to baseline detailed numerical simulations

  9. Laser Induced Damage in Optical Materials: 1979.

    DTIC Science & Technology

    1980-07-01

    an oscillator in laser fusion systems [8, 9]. Tm:YLF, pumped by an XeF laser , and emitting at 453 nm [10], is an efficient storage laser and is being...Chicklis, [4] Wilson, R., Varian Associates (private E.P. and Jenssen, H.P., XeF pumped communication). Tm:YLF an excimer excited storage laser , Technical...caused by pulsed laser -induced thermal stress were not signifi- cantly influenced by transverse heat conduction. However, the fluence levels were above

  10. Modulation of irinotecan-induced genomic DNA damage by theanine.

    PubMed

    Attia, Sabry

    2012-05-01

    The possible chemoprotective activity of theanine against irinotecan-induced genomic DNA damage towards mouse bone marrow cells was investigated. Chromosomal aberrations, DNA damage, micronuclei formation and mitotic activity were studied in the current study as markers of genomic damage. Oxidative DNA stress markers such as 8-hydroxydeoxyguanosine, lipid peroxidation, reduced and oxidized glutathione levels were assessed as a possible mechanism underlying this amelioration. Theanine was neither genotoxic nor cytotoxic in mice at doses equivalent to 30 or 60 mg/kg for 12 days. Pretreatment of mice with theanine significantly reduced irinotecan-induced genomic damage in the bone marrow cells and these effects were dose dependent. Irinotecan induced marked biochemical alterations characteristic of oxidative DNA stress, including increased 8-hydroxydeoxyguanosine, enhanced lipid peroxidation and reduction in the reduced/oxidized glutathione ratio. Prior administration of theanine ahead of irinotecan challenge ameliorated these oxidative DNA stress markers. Overall, this study provides for the first time that theanine has a protective role in the abatement of irinotecan-induced genomic damage in the bone marrow cells of mice that resides, at least in part, on its ability to modulate the cellular antioxidant levels and consequently protect bone marrow from irinotecan genotoxicity.

  11. Quercitrin protects skin from UVB-induced oxidative damage.

    PubMed

    Yin, Yuanqin; Li, Wenqi; Son, Young-Ok; Sun, Lijuan; Lu, Jian; Kim, Donghern; Wang, Xin; Yao, Hua; Wang, Lei; Pratheeshkumar, Poyil; Hitron, Andrew J; Luo, Jia; Gao, Ning; Shi, Xianglin; Zhang, Zhuo

    2013-06-01

    Exposure of the skin to ultraviolet B (UVB) radiation causes oxidative damage to skin, resulting in sunburn, photoaging, and skin cancer. It is generally believed that the skin damage induced by UV irradiation is a consequence of generation of reactive oxygen species (ROS). Recently, there is an increased interest in the use of natural products as chemopreventive agents for non-melanoma skin cancer (NMSC) due to their antioxidants and anti-inflammatory properties. Quercitrin, glycosylated form of quercetin, is the most common flavonoid in nature with antioxidant properties. The present study investigated the possible beneficial effects of quercitrin to inhibit UVB irradiation-induced oxidative damage in vitro and in vivo. Our results showed that quercitrin decreased ROS generation induced by UVB irradiation in JB6 cells. Quercitrin restored catalase expression and GSH/GSSG ratio reduced by UVB exposure, two major antioxidant enzymes, leading to reductions of oxidative DNA damage and apoptosis and protection of the skin from inflammation caused by UVB exposure. The present study demonstrated that quercitrin functions as an antioxidant against UVB irradiation-induced oxidative damage to skin. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Transesophageal Echocardiography and Radiation-induced Damages

    PubMed Central

    Cottini, Marzia; Polizzi, Vincenzo; Pino, Paolo Giuseppe; Buffa, Vitaliano; Musumeci, Francesco

    2016-01-01

    The long-term sequelae of mantle therapy include, especially lung and cardiac disease but also involve the vessels and the organs in the neck and thorax (such as thyroid, aorta, and esophagus). We presented the case of 66-year-old female admitted for congestive heart failure in radiation-induced heart disease. The patient had undergone to massive radiotherapy 42 years ago for Hodgkin's disease (type 1A). Transesophageal echocardiography was performed unsuccessfully with difficulty because of the rigidity and impedance of esophageal walls. Our case is an extraordinary report of radiotherapy's latency effect as a result of dramatic changes in the structure of mediastinum, in particular in the esophagus, causing unavailability of a transesophageal echocardiogram. PMID:27867461

  13. Blasting-induced damage in coal

    SciTech Connect

    Kabongo, K.K.

    1995-12-31

    The paper is drawn from a project intended to explore a technique of prediction, control and optimization of fracture in coal induced by blasting. It evaluates the fines generated in coal submitted to dynamic loading stresses in an impact stamp mortar. The aim is to analyze a complex phenomenon of coal response to blast-generated stresses from a series of discrete simulations of shock and gas actions in controllable processes. It is learned that despite the nucleation of primary crushing and fractures to originate from the point of impact energy in coal, a secondary crushing appears to depart from within the burden progressing towards the free boundaries. The extension of the secondary crushing zone appears to be influenced by the magnitude of the breaking stresses generated and the coal burden distance. A strong dependence of fines on the coal`s innate discontinuities (strength) and the energy input is highlighted.

  14. Pancreatic islet cell tumor

    MedlinePlus

    ... functions. These include blood sugar level and the production of stomach acid. Tumors that arise from islet ... try and shrink the tumors. If the abnormal production of hormones is causing symptoms, you may receive ...

  15. Alpha1-antitrypsin monotherapy prolongs islet allograft survival in mice.

    PubMed

    Lewis, Eli C; Shapiro, Leland; Bowers, Owen J; Dinarello, Charles A

    2005-08-23

    Islet transplantation for type 1 diabetic patients shows promising results with the use of nondiabetogenic immunosuppressive therapy. However, in addition to compromising the immune system of transplant recipients, long-term studies demonstrate that islet viability is impaired. Here, we demonstrate that, in the absence of immunosuppressive agents, monotherapy with clinical-grade human alpha1-antitrypsin (hAAT), the major serum serine-protease inhibitor, prolongs islet graft survival and normoglycemia in transplanted allogeneic diabetic mice, lasting until the development of anti-hAAT antibodies. Compared to untreated or albumin-control-treated graft recipients, which rejected islets at day 10, AAT-treated mice displayed diminished cellular infiltrates and intact intragraft insulin production throughout treatment. Using peritoneal infiltration models, we demonstrate that AAT decreases allogeneic fibroblast-elicited natural-killer-cell influx by 89%, CD3-positive cell influx by 44%, and thioglycolate-elicited neutrophil emigration by 66%. ATT also extended islet viability in mice after streptozotocin-induced beta cell toxicity. In vitro, several islet responses to IL-1beta/IFNgamma stimulation were examined. In the presence of AAT, islets displayed enhanced viability and inducible insulin secretion. Islets also released 36% less nitric oxide and 82% less macrophage inflammatory protein 1 alpha and expressed 63% fewer surface MHC class II molecules. TNFalpha release from IL-1beta/IFNgamma-stimulated islet cells was reduced by 99%, accompanied by an 8-fold increase in the accumulation of membrane TNFalpha on CD45-positive islet cells. In light of the established safety record and the nondiabetogenic potential of AAT, these data suggest that AAT may be beneficial as adjunctive therapy in patients undergoing islet transplantation.

  16. Automated Digital Image Analysis of Islet Cell Mass Using Nikon's Inverted Eclipse Ti Microscope and Software to Improve Engraftment may Help to Advance the Therapeutic Efficacy and Accessibility of Islet Transplantation across Centers.

    PubMed

    Gmyr, Valery; Bonner, Caroline; Lukowiak, Bruno; Pawlowski, Valerie; Dellaleau, Nathalie; Belaich, Sandrine; Aluka, Isanga; Moermann, Ericka; Thevenet, Julien; Ezzouaoui, Rimed; Queniat, Gurvan; Pattou, Francois; Kerr-Conte, Julie

    2015-01-01

    Reliable assessment of islet viability, mass, and purity must be met prior to transplanting an islet preparation into patients with type 1 diabetes. The standard method for quantifying human islet preparations is by direct microscopic analysis of dithizone-stained islet samples, but this technique may be susceptible to inter-/intraobserver variability, which may induce false positive/negative islet counts. Here we describe a simple, reliable, automated digital image analysis (ADIA) technique for accurately quantifying islets into total islet number, islet equivalent number (IEQ), and islet purity before islet transplantation. Islets were isolated and purified from n = 42 human pancreata according to the automated method of Ricordi et al. For each preparation, three islet samples were stained with dithizone and expressed as IEQ number. Islets were analyzed manually by microscopy or automatically quantified using Nikon's inverted Eclipse Ti microscope with built-in NIS-Elements Advanced Research (AR) software. The AIDA method significantly enhanced the number of islet preparations eligible for engraftment compared to the standard manual method ( p < 0.001). Comparisons of individual methods showed good correlations between mean values of IEQ number ( r(2) = 0.91) and total islet number ( r(2) = 0.88) and thus increased to r(2) = 0.93 when islet surface area was estimated comparatively with IEQ number. The ADIA method showed very high intraobserver reproducibility compared to the standard manual method ( p < 0.001). However, islet purity was routinely estimated as significantly higher with the manual method versus the ADIA method ( p < 0.001). The ADIA method also detected small islets between 10 and 50 μm in size. Automated digital image analysis utilizing the Nikon Instruments software is an unbiased, simple, and reliable teaching tool to comprehensively assess the individual size of each islet cell preparation prior to transplantation. Implementation of this

  17. Automated digital image analysis of islet cell mass using Nikon's inverted eclipse Ti microscope and software to improve engraftment may help to advance the therapeutic efficacy and accessibility of islet transplantation across centers.

    PubMed

    Gmyr, Valery; Bonner, Caroline; Lukowiak, Bruno; Pawlowski, Valerie; Dellaleau, Nathalie; Belaich, Sandrine; Aluka, Isanga; Moermann, Ericka; Thevenet, Julien; Ezzouaoui, Rimed; Queniat, Gurvan; Pattou, Francois; Kerr-Conte, Julie

    2015-01-01

    Reliable assessment of islet viability, mass, and purity must be met prior to transplanting an islet preparation into patients with type 1 diabetes. The standard method for quantifying human islet preparations is by direct microscopic analysis of dithizone-stained islet samples, but this technique may be susceptible to inter-/intraobserver variability, which may induce false positive/negative islet counts. Here we describe a simple, reliable, automated digital image analysis (ADIA) technique for accurately quantifying islets into total islet number, islet equivalent number (IEQ), and islet purity before islet transplantation. Islets were isolated and purified from n = 42 human pancreata according to the automated method of Ricordi et al. For each preparation, three islet samples were stained with dithizone and expressed as IEQ number. Islets were analyzed manually by microscopy or automatically quantified using Nikon's inverted Eclipse Ti microscope with built-in NIS-Elements Advanced Research (AR) software. The AIDA method significantly enhanced the number of islet preparations eligible for engraftment compared to the standard manual method (p < 0.001). Comparisons of individual methods showed good correlations between mean values of IEQ number (r(2) = 0.91) and total islet number (r(2) = 0.88) and thus increased to r(2) = 0.93 when islet surface area was estimated comparatively with IEQ number. The ADIA method showed very high intraobserver reproducibility compared to the standard manual method (p < 0.001). However, islet purity was routinely estimated as significantly higher with the manual method versus the ADIA method (p < 0.001). The ADIA method also detected small islets between 10 and 50 µm in size. Automated digital image analysis utilizing the Nikon Instruments software is an unbiased, simple, and reliable teaching tool to comprehensively assess the individual size of each islet cell preparation prior to transplantation. Implementation of this

  18. UV and ionizing radiations induced DNA damage, differences and similarities

    NASA Astrophysics Data System (ADS)

    Ravanat, Jean-Luc; Douki, Thierry

    2016-11-01

    Both UV and ionizing radiations damage DNA. Two main mechanisms, so-called direct and indirect pathways, are involved in the degradation of DNA induced by ionizing radiations. The direct effect of radiation corresponds to direct ionization of DNA (one electron ejection) whereas indirect effects are produced by reactive oxygen species generated through water radiolysis, including the highly reactive hydroxyl radicals, which damage DNA. UV (and visible) light damages DNA by again two distinct mechanisms. UVC and to a lesser extend UVB photons are directly absorbed by DNA bases, generating their excited states that are at the origin of the formation of pyrimidine dimers. UVA (and visible) light by interaction with endogenous or exogenous photosensitizers induce the formation of DNA damage through photosensitization reactions. The excited photosensitizer is able to induce either a one-electron oxidation of DNA (type I) or to produce singlet oxygen (type II) that reacts with DNA. In addition, through an energy transfer from the excited photosensitizer to DNA bases (sometime called type III mechanism) formation of pyrimidine dimers could be produced. Interestingly it has been shown recently that pyrimidine dimers are also produced by direct absorption of UVA light by DNA, even if absorption of DNA bases at these wavelengths is very low. It should be stressed that some excited photosensitizers (such as psoralens) could add directly to DNA bases to generate adducts. The review will described the differences and similarities in terms of damage formation (structure and mechanisms) between these two physical genotoxic agents.

  19. Hardening measures for bipolar transistors against microwave-induced damage

    NASA Astrophysics Data System (ADS)

    Chai, Chang-Chun; Ma, Zhen-Yang; Ren, Xing-Rong; Yang, Yin-Tang; Zhao, Ying-Bo; Yu, Xin-Hai

    2013-06-01

    In the present paper we study the influences of the bias voltage and the external components on the damage progress of a bipolar transistor induced by high-power microwaves. The mechanism is presented by analyzing the variation in the internal distribution of the temperature in the device. The findings show that the device becomes less vulnerable to damage with an increase in bias voltage. Both the series diode at the base and the relatively low series resistance at the emitter, Re, can obviously prolong the burnout time of the device. However, Re will aid damage to the device when the value is sufficiently high due to the fact that the highest hot spot shifts from the base-emitter junction to the base region. Moreover, the series resistance at the base Rb will weaken the capability of the device to withstand microwave damage.

  20. Enhancement of in vitro and in vivo function of agarose-encapsulated porcine islets by changes in the islet microenvironment.

    PubMed

    Holdcraft, Robert W; Gazda, Lawrence S; Circle, Lisa; Adkins, Hollie; Harbeck, Steven G; Meyer, Eric D; Bautista, Melissa A; Martis, Prithy C; Laramore, Melissa A; Vinerean, Horatiu V; Hall, Richard D; Smith, Barry H

    2014-01-01

    The transplantation of porcine islets of Langerhans to treat type 1 diabetes may provide a solution to the demand for insulin-producing cells. Porcine islets encapsulated in agarose-agarose macrobeads have been shown to function in nonimmunosuppressed xenogeneic models of both streptozotocin-induced and autoimmune type 1 diabetes. One advantage of agarose encapsulation is the ability to culture macrobeads for extended periods, permitting microbiological and functional assessment. Herein we describe optimization of the agarose matrix that results in improved islet function. Porcine islets (500 IEQs) from retired breeding sows were encapsulated in 1.5% SeaKem Gold (SG), 0.8% SG, or 0.8% Litex (Li) agarose, followed by an outer capsule of 5% SG agarose. Insulin production by the encapsulated islets exhibited an agarose-specific effect with 20% (0.8% SG) to 50% (0.8% Li) higher initial insulin production relative to 1.5% SG macrobeads. Insulin production was further increased by 40-50% from week 2 to week 12 in both agarose types at the 0.8% concentration, whereas islets encapsulated in 1.5% SG agarose increased insulin production by approximately 20%. Correspondingly, fewer macrobeads were required to restore normoglycemia in streptozotocin-induced diabetic female CD(SD) rats that received 0.8% Li (15 macrobeads) or 0.8% SG (17 macrobeads) as compared to 1.5% SG (19 macrobeads). Islet cell proliferation was also observed during the first 2 months postencapsulation, peaking at 4 weeks, where approximately 50% of islets contained proliferative cells, including β-cells, regardless of agarose type. These results illustrate the importance of optimizing the microenvironment of encapsulated islets to improve islet performance and advance the potential of islet xenotransplantation for the treatment of type 1 diabetes.

  1. Heat Induced Damage Detection by Terahertz (THz) Radiation

    NASA Astrophysics Data System (ADS)

    Rahani, Ehsan Kabiri; Kundu, Tribikram; Wu, Ziran; Xin, Hao

    2011-06-01

    Terahertz (THz) and sub-terahertz imaging and spectroscopy are becoming increasingly popular nondestructive evaluation techniques for damage detection and characterization of materials. THz radiation is being used for inspecting ceramic foam tiles used in TPS (Thermal Protection System), thick polymer composites and polymer tiles that are not good conductors of ultrasonic waves. Capability of THz electromagnetic waves in detecting heat induced damage in porous materials is investigated in this paper. Porous pumice stone blocks are subjected to long time heat exposures to produce heat induced damage in the block. The dielectric properties extracted from THz TDS (Time Domain Spectroscopy) measurements are compared for different levels of heat exposure. Experimental results show noticeable and consistent change in dielectric properties with increasing levels of heat exposure, well before its melting point.

  2. Mitochondrial and nuclear DNA damage induced by 5-aminolevulinic acid.

    PubMed

    Onuki, Janice; Chen, Yiming; Teixeira, Priscila C; Schumacher, Robert I; Medeiros, Marisa H G; Van Houten, Bennett; Di Mascio, Paolo

    2004-12-15

    5-Aminolevulinic acid (ALA) is a heme precursor accumulated in plasma and in organs in acute intermittent porphyria (AIP), a disease associated with neuromuscular dysfunction and increased incidence of hepatocellular carcinoma (HCC). Liver biopsies of AIP patients showed odd-shaped mitochondria and autophagic vacuoles containing well-preserved mitochondria. ALA yields reactive oxygen species upon metal-catalyzed oxidation and causes in vivo and in vitro impairment of rat liver mitochondria and DNA damage. Using a quantitative polymerase chain reaction assay, we demonstrated that ALA induces a dose-dependent damage in nuclear and mitochondrial DNA in human SVNF fibroblasts and rat PC12 cells. CHO cells treated with ALA also show nuclear DNA damage and human HepG2 cells entered in apoptosis and necrosis induced by ALA and its dimerization product, DHPY. The present data provide additional information on the genotoxicity of ALA, reinforcing the hypothesis that it may be involved in the development of HCC in AIP patients.

  3. Plasmid DNA damage induced by helium atmospheric pressure plasma jet

    NASA Astrophysics Data System (ADS)

    Han, Xu; Cantrell, William A.; Escobar, Erika E.; Ptasinska, Sylwia

    2014-03-01

    A helium atmospheric pressure plasma jet (APPJ) is applied to induce damage to aqueous plasmid DNA. The resulting fractions of the DNA conformers, which indicate intact molecules or DNA with single- or double-strand breaks, are determined using agarose gel electrophoresis. The DNA strand breaks increase with a decrease in the distance between the APPJ and DNA samples under two working conditions of the plasma source with different parameters of applied electric pulses. The damage level induced in the plasmid DNA is also enhanced with increased plasma irradiation time. The reactive species generated in the APPJ are characterized by optical emission spectra, and their roles in possible DNA damage processes occurring in an aqueous environment are also discussed.

  4. Shock-induced damage in rocks: Application to impact cratering

    NASA Astrophysics Data System (ADS)

    Ai, Huirong

    Shock-induced damage beneath impact craters is studied in this work. Two representative terrestrial rocks, San Marcos granite and Bedford limestone, are chosen as test target. Impacts into the rock targets with different combinations of projectile material, size, impact angle, and impact velocity are carried out at cm scale in the laboratory. Shock-induced damage and fracturing would cause large-scale compressional wave velocity reduction in the recovered target beneath the impact crater. The shock-induced damage is measured by mapping the compressional wave velocity reduction in the recovered target. A cm scale nondestructive tomography technique is developed for this purpose. This technique is proved to be effective in mapping the damage in San Marcos granite, and the inverted velocity profile is in very good agreement with the result from dicing method and cut open directly. Both compressional velocity and attenuation are measured in three orthogonal directions on cubes prepared from one granite target impacted by a lead bullet at 1200 m/s. Anisotropy is observed from both results, but the attenuation seems to be a more useful parameter than acoustic velocity in studying orientation of cracks. Our experiments indicate that the shock-induced damage is a function of impact conditions including projectile type and size, impact velocity, and target properties. Combined with other crater phenomena such as crater diameter, depth, ejecta, etc., shock-induced damage would be used as an important yet not well recognized constraint for impact history. The shock-induced damage is also calculated numerically to be compared with the experiments for a few representative shots. The Johnson-Holmquist strength and failure model, initially developed for ceramics, is applied to geological materials. Strength is a complicated function of pressure, strain, strain rate, and damage. The JH model, coupled with a crack softening model, is used to describe both the inelastic response of

  5. Selective therapeutic effect of cornus officinalis fruits on the damage of different organs in STZ-induced diabetic rats.

    PubMed

    Han, Yunkyung; Jung, Hyo Won; Park, Yong-Ki

    2014-01-01

    The aim of the present study was to identify the selective therapeutic effects of Corni Fructus (Cornus officinalis Sieb. et Zucc.) on different organs in streptozotocin (STZ)-induced diabetic rats. Diabetes in rats was induced by intraperitonal injection with STZ at a dose of 30 mg/kg body weight (bw) for 3 days (once per a day). STZ-induced diabetic rats were orally administrated Corni Fructus (CF) extract at 300 mg/kg or metformin at 250 mg/kg daily for 4 weeks. Blood glucose and triglyceride (TG) in sera and urine total volume were measured. Histopathological changes of different organs, pancreas, liver, kidney, and lung tissues were observed by H&E staining. The expression of insulin and α-smooth muscle actin (α-SMA) was investigated in pancreas, and kidney by immunohistochemistry, respectively. The results revealed that CF extract significantly decreased the serum levels of blood glucose, and TG, and also urine total volume in STZ-induced diabetic rats. The histological examinations revealed amelioration of diabetes-induced pancreas injury including pathological changes of the Langerhans's islet and glomerular with their loss after the administration of CF extraction. Moreover, the administration of CF extract increased the numbers of insulin releasing beta cells in pancreas and also inhibited the expression of α-SMA in kidney of STZ-induced diabetic rats. On the other hand, CF extract showed no effect on the pathological damages of liver and lung in STZ-induced diabetic rats. These results demonstrated that CF extract may have a selective therapeutic potential through the control of hyperglycemia, and the protection of pancreas and kidney against diabetic damage.

  6. Induction of Protective Genes Leads to Islet Survival and Function

    PubMed Central

    Wang, Hongjun; Ferran, Christiane; Attanasio, Chiara; Calise, Fulvio; Otterbein, Leo E.

    2011-01-01

    Islet transplantation is the most valid approach to the treatment of type 1 diabetes. However, the function of transplanted islets is often compromised since a large number of β cells undergo apoptosis induced by stress and the immune rejection response elicited by the recipient after transplantation. Conventional treatment for islet transplantation is to administer immunosuppressive drugs to the recipient to suppress the immune rejection response mounted against transplanted islets. Induction of protective genes in the recipient (e.g., heme oxygenase-1 (HO-1), A20/tumor necrosis factor alpha inducible protein3 (tnfaip3), biliverdin reductase (BVR), Bcl2, and others) or administration of one or more of the products of HO-1 to the donor, the islets themselves, and/or the recipient offers an alternative or synergistic approach to improve islet graft survival and function. In this perspective, we summarize studies describing the protective effects of these genes on islet survival and function in rodent allogeneic and xenogeneic transplantation models and the prevention of onset of diabetes, with emphasis on HO-1, A20, and BVR. Such approaches are also appealing to islet autotransplantation in patients with chronic pancreatitis after total pancreatectomy, a procedure that currently only leads to 1/3 of transplanted patients being diabetes-free. PMID:22220267

  7. Postnatal β-cell maturation is associated with islet-specific microRNA changes induced by nutrient shifts at weaning

    PubMed Central

    Jacovetti, Cécile; Matkovich, Scot J.; Rodriguez-Trejo, Adriana; Guay, Claudiane; Regazzi, Romano

    2015-01-01

    Glucose-induced insulin secretion is an essential function of pancreatic β-cells that is partially lost in individuals affected by Type 2 diabetes. This unique property of β-cells is acquired through a poorly understood postnatal maturation process involving major modifications in gene expression programs. Here we show that β-cell maturation is associated with changes in microRNA expression induced by the nutritional transition that occurs at weaning. When mimicked in newborn islet cells, modifications in the level of specific microRNAs result in a switch in the expression of metabolic enzymes and cause the acquisition of glucose-induced insulin release. Our data suggest microRNAs have a central role in postnatal β-cell maturation and in the determination of adult functional β-cell mass. A better understanding of the events governing β-cell maturation may help understand why some individuals are predisposed to developing diabetes and could lead to new strategies for the treatment of this common metabolic disease. PMID:26330140

  8. Potential role of punicalagin against oxidative stress induced testicular damage

    PubMed Central

    Rao, Faiza; Tian, Hui; Li, Wenqing; Hung, Helong; Sun, Fei

    2016-01-01

    Punicalagin is isolated from pomegranate and widely used for the treatment of different diseases in Chinese traditional medicine. This study aimed to evaluate the effect of Punicalagin (purity ≥98%) on oxidative stress induced testicular damage and its effect on fertility. We detected the antioxidant potential of punicalagin in lipopolysaccharide (LPS) induced oxidative stress damage in testes, also tried to uncover the boosting fertility effect of Punicalagin (PU) against oxidative stress-induced infertility. Results demonstrated that 9 mg kg−1 for 7 days treatment significantly decreases LPS induced oxidative damage in testes and nitric oxide production. The administration of oxidative stress resulted in a significant reduction in testes antioxidants GSH, T-SOD, and CAT raised LPO, but treatment with punicalagin for 7 days increased antioxidant defense GSH, T-SOD, and CAT by the end of the experiment and reduced LPO level as well. PU also significantly activates Nrf2, which is involved in regulation of antioxidant defense systems. Hence, the present research categorically elucidates the protective effect of punicalagin against LPS induced oxidative stress induced perturbation in the process of spermatogenesis and significantly increased sperm health and number. Moreover, fertility success significantly decreased in LPS-injected mice compared to controls. Mice injected with LPS had fertility indices of 12.5%, while others treated with a combination of PU + LPS exhibited 75% indices. By promoting fertility and eliminating oxidative stress and inflammation, PU may be a useful nutrient for the treatment of infertility. PMID:26763544

  9. Potential role of punicalagin against oxidative stress induced testicular damage.

    PubMed

    Rao, Faiza; Tian, Hui; Li, Wenqing; Hung, Helong; Sun, Fei

    2016-01-01

    Punicalagin is isolated from pomegranate and widely used for the treatment of different diseases in Chinese traditional medicine. This study aimed to evaluate the effect of Punicalagin (purity ≥98%) on oxidative stress induced testicular damage and its effect on fertility. We detected the antioxidant potential of punicalagin in lipopolysaccharide (LPS) induced oxidative stress damage in testes, also tried to uncover the boosting fertility effect of Punicalagin (PU) against oxidative stress-induced infertility. Results demonstrated that 9 mg kg-1 for 7 days treatment significantly decreases LPS induced oxidative damage in testes and nitric oxide production. The administration of oxidative stress resulted in a significant reduction in testes antioxidants GSH, T-SOD, and CAT raised LPO, but treatment with punicalagin for 7 days increased antioxidant defense GSH, T-SOD, and CAT by the end of the experiment and reduced LPO level as well. PU also significantly activates Nrf2, which is involved in regulation of antioxidant defense systems. Hence, the present research categorically elucidates the protective effect of punicalagin against LPS induced oxidative stress induced perturbation in the process of spermatogenesis and significantly increased sperm health and number. Moreover, fertility success significantly decreased in LPS-injected mice compared to controls. Mice injected with LPS had fertility indices of 12.5%, while others treated with a combination of PU + LPS exhibited 75% indices. By promoting fertility and eliminating oxidative stress and inflammation, PU may be a useful nutrient for the treatment of infertility.

  10. Autophagy Induced by Calcium Phosphate Precipitates Targets Damaged Endosomes*

    PubMed Central

    Chen, Xi; Khambu, Bilon; Zhang, Hao; Gao, Wentao; Li, Min; Chen, Xiaoyun; Yoshimori, Tamotsu; Yin, Xiao-Ming

    2014-01-01

    Calcium phosphate precipitates (CPPs) form complexes with DNA, which enter cells via endocytosis. Under this condition CPPs induce autophagy via the canonic autophagy machinery. Here we showed that CPP-induced autophagy was also dependent on endocytosis as the process was significantly inhibited by methyl-β-cyclodextrin and dynasore, which suppress clathrin-dependent endocytosis. Consistently, CPP treatment triggered the formation of filipin-positive intracellular vesicles whose membranes are rich in cholesterol. Unexpectedly, these vesicles were also positive for galectin 3, suggesting that they were damaged and the membrane glycans became accessible to galectins to bind. Endosome damage was caused by endocytosis of CPPs and was reversed by calcium chelators or by endocytosis inhibitors. Notably, CPP-induced LC3-positive autophagosomes were colocalized with galectin 3, ubiquitin, and p62/SQSTM1. Inhibition of galectin 3 reduced p62 puncta and autophagosome formation. Knockdown of p62 additionally inhibited the colocalization of autophagosomes with galectins. Furthermore, most of the galectin 3-positive vesicles were colocalized with Rab7 or LAMP1. Agents that affect endosome/lysosome maturation and function, such as bafilomycin A1, also significantly affected CPP-induced tubulovesicular autophagosome formation. These findings thus indicate that endocytosed CPPs caused endosome damage and recruitment of galectins, particularly at the later endosome stage, which led to the interaction of the autophagosomal membranes with the damaged endosome in the presence of p62. PMID:24619419

  11. NBQX and TCP prevent soman-induced hippocampal damage

    SciTech Connect

    Lallement, G.; Carpentier, P.; Pernot-Marino, I.; Baubichon, D.; Blanchet, G.

    1993-05-13

    In a previous investigation we demonstrated that the measurement of w3 (peripheral-type benzodiazepine) binding site densities could be of widespread applicability in the localization and quantification of soman-induced damage in the central nervous system. We thus used this marker to assess, in mouse hippocampus, the neuroprotective activity against soman-induced brain damage of NBQX and TCP which are respective antagonists of non-NMDA and NMDA glutamatergic receptors. Injection of NBQX at 20 or 40 mg/kg 5 min prior to soman totally prevented the neuronal damage. Comparatively, TCP had neuroprotective efficacy when administered at l mg/kg 5 min prior to soman followed by a reinjection 1 hour after. These results demonstrate that both NBQX and TCP afford a satisfactory neuroprotection against soman-induced brain damage. Since it is known that the neuropathology due to soman is closely seizure-related, it is likely that the neuroprotective activities of NBQX and TCP are related to the respective roles of non-NMDA and NMDA receptors in the onset and maintenance of soman-induced seizures.

  12. Glucagon-like peptide 1 receptor agonist ameliorates the insulin resistance function of islet β cells via the activation of PDX-1/JAK signaling transduction in C57/BL6 mice with high-fat diet-induced diabetes.

    PubMed

    Hao, Tao; Zhang, Hongtao; Li, Sheyu; Tian, Haoming

    2017-04-01

    Long-term exposure to a high-fat diet (HFD) causes glucotoxicity and lipotoxicity in islet β cells and leads to the development of metabolic dysfunctions. Reductions in pancreatic and duodenal homeobox-1 (PDX-1) expression have been shown to induce type 2 diabetes mellitus by causing impairments to islet β cells. Glucagon-like peptide 1 (GLP-1) treatment reduces endogenous insulin resistance in HFD-induced type 2 diabetes mellitus. In the present study, the underlying mechanism by which GLP-1 exerts its function in type 2 diabetes mellitus was investigated. The effect of liraglutide (GLP-1 receptor agonist) administration on glucose tolerance, insulin release, and glucose-dependent insulinotropic polypeptide level was detected in a HFD-induced diabetes C57/BL6 mouse model. Moreover, the role of liraglutide administration on the activity of PDX-1 was quantified to demonstrate the association between the two indicators. The results showed that administration of liraglutide could ameliorate the impairments to β cells due to HFD consumption. Liraglutide restored the insulin capacity and stimulated glucose disposal by improving the function and increasing the number of islet β cells. Furthermore, the hyperplasia and redundant function of islet α cells were inhibited by liraglutide treatment as well. At the molecular level, administration of liraglutide induced the expression of PDX-1, MafA, p-JAK2 and p-Stat3 in HFD model to relatively normal levels. It was suggested that the effect of liraglutide-induced activation of GLP-1 was exerted via activation of PDX-1 rather than its function in decreasing body weight. The study demonstrated that GLP-1 played an essential role in type 2 diabetes mellitus.

  13. Stimulus-secretion coupling of arginine-induced insulin release. Uptake of metabolized and nonmetabolized cationic amino acids by pancreatic islets

    SciTech Connect

    Blachier, F.; Mourtada, A.; Sener, A.; Malaisse, W.J.

    1989-01-01

    In order to assess the possible role of L-arginine accumulation in islet cells as a determinant of its insulinotropic action, the uptake of L-arginine and other cationic amino acids (L-ornithine, L-homoarginine, D,L-alpha-methylornithine, D,L-alpha-difluoromethylornithine) by rat pancreatic islets was compared to the ionic and secretory responses of the islets to the same amino acids. A tight correlation was found between the net uptake of these amino acids and their capacity to stimulate 86Rb efflux, 45Ca uptake and efflux, and insulin release. In the latter respect, there was little difference between metabolized and nonmetabolized amino acids. Thus, although L-homoarginine and 4-amino-1-guanylpiperidine-4-carboxylic acid failed to act as a substrate for either arginase or amino acid aminotransferase in islet homogenates, they both stimulated 86Rb efflux, 45Ca uptake and efflux, and insulin secretion in intact islets. These findings are compatible with the view that the accumulation of these positively charged amino acids in islet cells represents an essential determinant of their secretory action. Hence, the release of insulin evoked by these amino acids could be due to depolarization of the plasma membrane with subsequent gating of voltage-sensitive Ca2+ channels and/or to some other biophysical effect, as suggested by the persistence of a sizeable secretory response to L-arginine or L-ornithine in islets perifused at a high concentrations of extracellular K+ (50 mM).

  14. Avermectin induced inflammation damage in king pigeon brain.

    PubMed

    Chen, Li-Jie; Sun, Bao-Hong; Qu, Jian Ping; Xu, Shiwen; Li, Shu

    2013-11-01

    To determine the effect of Avermectin (AVM) on inflammation damage in king pigeon brain, eighty two-month-old American king pigeons were randomly divided into four groups, and were fed with either commercial diet or AVM-supplemented diet containing 20 mg kg(-1)diet, 40 mg kg(-1)diet, and 60 mg kg(-1)diet AVM for 30, 60 and 90 d, respectively. Then, the expression level of inflammatory factors (iNOS, PTGEs, NF-κB), histological damage, and ultra-structural damage were examined. It showed that AVM caused higher expressions (P<0.05) of iNOS, PTGEs, NF-κB with disorganized histological and ultra-structural structures in cerebrum, cerebellum, and optic lobe. Meanwhile, inflammatory and histopathological damage were induced by AVM in king pigeon brains. In addition, the main targeted organelle in nervous system was mitochondria, which indicated that mitochondria may be relevant to the process of inflammation induced by AVM. To our best knowledge, this is the first report to study the toxic effect of AVM on inflammatory damage in king pigeon. Thus, the information presented in this study is believed to be helpful in supplementing data for further AVM toxicity study.

  15. Overloaded training increases exercise-induced oxidative stress and damage.

    PubMed

    Palazzetti, Stephane; Richard, Marie-Jeanne; Favier, Alain; Margaritis, Irene

    2003-08-01

    We hypothesized that overloaded training (OT) in triathlon would induce oxidative stress and damage on muscle and DNA. Nine male triathletes and 6 male sedentary subjects participated in this study. Before and after a 4-week OT, triathletes exercised for a duathlon. Blood ratio of reduced vs. oxidized glutathione (GSH/GSSG), plasma thiobarbituric acid reactive substances (TBARS), leukocyte DNA damage, creatine kinase (CK), and CK-MB mass in plasma, erythrocyte superoxide dismutase (SOD) activity, erythrocyte and plasma glutathione peroxidase (GSH-Px) activities, and plasma total antioxidant status (TAS) were measured before and after OT in pre- and postexercise situations. Triathletes were overloaded in response to OT. In rest conditions, OT induced plasma GSH-Px activity increase and plasma TAS decrease (both p < 0.05). In exercise conditions, OT resulted in higher exercise-induced variations of blood GSH/GSSG ratio, TBARS level (both p < 0.05), and CK-MB mass (p < 0.01) in plasma; and decreased TAS response (p < 0.05). OT could compromise the antioxidant defense mechanism with respect to exercise-induced response. The resulting increased exercise-induced oxidative stress and further cellular susceptibility to damage needs more study.

  16. Obesity Exacerbates Sepsis-Induced Oxidative Damage in Organs.

    PubMed

    Petronilho, Fabricia; Giustina, Amanda Della; Nascimento, Diego Zapelini; Zarbato, Graciela Freitas; Vieira, Andriele Aparecida; Florentino, Drielly; Danielski, Lucinéia Gainski; Goldim, Mariana Pereira; Rezin, Gislaine Tezza; Barichello, Tatiana

    2016-12-01

    Sepsis progression is linked to the imbalance between reactive oxygen species and antioxidant enzymes. Sepsis affects multiple organs, but when associated with a chronic inflammatory disease, such as obesity, it may be exacerbated. We hypothesized that obesity could aggravate the oxidative damage to peripheral organs of rats submitted to an animal model of sepsis. Male Wistar rats aged 8 weeks received hypercaloric nutrition for 2 months to induce obesity. Sepsis was induced by cecal ligation and puncture (CLP) procedure, and sham-operated rats were considered as control group. The experimental groups were divided into sham + eutrophic, sham + obese, CLP + eutrophic, and CLP + obese. Twelve and 24 h after surgery, oxidative damage to lipids and proteins and superoxide dismutase (SOD) and catalase (CAT) activities were evaluated in the liver, lung, kidney, and heart. The data indicate that obese rats subjected to sepsis present oxidative stress mainly in the lung and liver. This alteration reflected an oxidative damage to lipids and proteins and an imbalance of SOD and CAT levels, especially 24 h after sepsis. It follows that obesity due to its pro-inflammatory phenotype can aggravate sepsis-induced damage in peripheral organs.

  17. Mitochondrial DNA damage induces apoptosis in senescent cells

    PubMed Central

    Laberge, R-M; Adler, D; DeMaria, M; Mechtouf, N; Teachenor, R; Cardin, G B; Desprez, P-Y; Campisi, J; Rodier, F

    2013-01-01

    Senescence is a cellular response to damage and stress. The senescence response prevents cancer by suppressing the proliferation of cells with a compromised genome and contributes to optimal wound healing in normal tissues. Persistent senescent cells are also thought to drive aging and age-associated pathologies through their secretion of inflammatory factors that modify the tissue microenvironment and alter the function of nearby normal or transformed cells. Understanding how senescent cells alter the microenvironment would be aided by the ability to induce or eliminate senescent cells at will in vivo. Here, we combine the use of the synthetic nucleoside analog ganciclovir (GCV) with herpes simplex virus thymidine kinase (HSVtk) activity to create or eliminate senescent human cells. We show that low concentrations of GCV induce senescence through the accumulation of nuclear DNA damage while higher concentrations of GCV, similar to those used in vivo, kill non-dividing senescent cells via mitochondrial DNA (mtDNA) damage and caspase-dependent apoptosis. Using this system, we effectively eliminated xenografted normal human senescent fibroblasts or induced senescence in human breast cancer cells in vivo. Thus, cellular senescence and mtDNA damage are outcomes of synthetic nucleoside analog treatment, indicating that the GCV–HSVtk combination can be used effectively to promote the targeted formation or eradication of senescent cells. PMID:23868060

  18. Mitochondrial DNA damage induces apoptosis in senescent cells.

    PubMed

    Laberge, R-M; Adler, D; DeMaria, M; Mechtouf, N; Teachenor, R; Cardin, G B; Desprez, P-Y; Campisi, J; Rodier, F

    2013-07-18

    Senescence is a cellular response to damage and stress. The senescence response prevents cancer by suppressing the proliferation of cells with a compromised genome and contributes to optimal wound healing in normal tissues. Persistent senescent cells are also thought to drive aging and age-associated pathologies through their secretion of inflammatory factors that modify the tissue microenvironment and alter the function of nearby normal or transformed cells. Understanding how senescent cells alter the microenvironment would be aided by the ability to induce or eliminate senescent cells at will in vivo. Here, we combine the use of the synthetic nucleoside analog ganciclovir (GCV) with herpes simplex virus thymidine kinase (HSVtk) activity to create or eliminate senescent human cells. We show that low concentrations of GCV induce senescence through the accumulation of nuclear DNA damage while higher concentrations of GCV, similar to those used in vivo, kill non-dividing senescent cells via mitochondrial DNA (mtDNA) damage and caspase-dependent apoptosis. Using this system, we effectively eliminated xenografted normal human senescent fibroblasts or induced senescence in human breast cancer cells in vivo. Thus, cellular senescence and mtDNA damage are outcomes of synthetic nucleoside analog treatment, indicating that the GCV-HSVtk combination can be used effectively to promote the targeted formation or eradication of senescent cells.

  19. Zebrafish fin regeneration after cryoinjury-induced tissue damage

    PubMed Central

    Chassot, Bérénice; Pury, David

    2016-01-01

    ABSTRACT Although fin regeneration following an amputation procedure has been well characterized, little is known about the impact of prolonged tissue damage on the execution of the regenerative programme in the zebrafish appendages. To induce histolytic processes in the caudal fin, we developed a new cryolesion model that combines the detrimental effects of freezing/thawing and ischemia. In contrast to the common transection model, the damaged part of the fin was spontaneously shed within two days after cryoinjury. The remaining stump contained a distorted margin with a mixture of dead material and healthy cells that concomitantly induced two opposing processes of tissue debris degradation and cellular proliferation, respectively. Between two and seven days after cryoinjury, this reparative/proliferative phase was morphologically featured by displaced fragments of broken bones. A blastemal marker msxB was induced in the intact mesenchyme below the damaged stump margin. Live imaging of epithelial and osteoblastic transgenic reporter lines revealed that the tissue-specific regenerative programmes were initiated after the clearance of damaged material. Despite histolytic perturbation during the first week after cryoinjury, the fin regeneration resumed and was completed without further alteration in comparison to the simple amputation model. This model reveals the powerful ability of the zebrafish to restore the original appendage architecture after the extended histolysis of the stump. PMID:27215324

  20. A quantitative study of sodium tungstate protective effect on pancreatic beta cells in streptozotocin-induced diabetic rats.

    PubMed

    Heidari, Zahra; Mahmoudzadeh-Sagheb, Hamidreza; Moudi, Bita

    2008-12-01

    Diabetes is a major public health problem. Development of new therapies that are able to improve glycemia management, cure diabetes, and can even protect from it, are of great interest. This study investigated the protective effect of sodium tungstate against STZ-induced beta-cell damages by means of stereological methods. Sixty rats were divided into six groups: control (C), tungstate-treated control (TC), STZ-induced diabetic (D), STZ-induced diabetic rats were treated by sodium tungstate from 1 week before STZ injection (TDB), food-restricted diabetic (FRD), and diabetic rats treated with sodium tungstate 1 week after STZ administration (TDA). Stereological estimation of pancreas volume, islets volume density, volume-weighted mean islets volume and mass of beta cells, islets, and pancreas and total number of islets were done. Islets volume density, volume-weighted mean islets volume, and mass of beta cells, islets, and pancreas of TDB group was significantly higher than D, FRD and TDA groups (P<0.001) and was comparable to controls (C and TC groups). Total number of islets, pancreas wet weight and volume did not show any significant changes between these groups (P>0.05). Results suggested that sodium tungstate preserves pancreatic beta cells from STZ-induced damages and diabetes induction in rats.

  1. Computational modeling of process induced damage during plasma clean

    NASA Astrophysics Data System (ADS)

    Rauf, S.; Haggag, A.; Moosa, M.; Ventzek, P. L. G.

    2006-07-01

    When partially completed circuits come in contact with plasmas during integrated circuit fabrication, current from the plasma can potentially damage active devices on the wafer. A suite of computational models is used in this article to investigate damage to ultrathin (1.0-5.5nm) transistor gate dielectric (SiO2) during Ar /O2 based plasma cleaning in a capacitively coupled plasma reactor. This modeling infrastructure includes a two-dimensional plasma equipment model for relating process control parameters to ion and electron currents, a three-dimensional model for flux density calculation within a circular via, an electrostatic model for computing potential across the gate dielectric, and a percolation model to investigate dielectric damage characteristics. Computational results show that when the plasma current comes in contact with the gate dielectric, the gate dielectric rapidly charges up and the potential difference across the dielectric saturates at the level necessary to support the plasma induced current. The steady-state voltage across the dielectric determines the propensity of irreversible damage that can occur under this electrical stress. Gate dielectric damage was found to be most sensitively linked to dielectric thickness. As thin dielectrics (<2.0nm) are leaky, direct tunneling current flow ensures that the potential drop across the gate dielectric remains small. As a consequence, the dielectric is able to withstand the plasma current and the probability of damage is small. However, for thicker dielectrics where Fowler-Nordheim tunneling is dominant, a large voltage builds up across the gate dielectric due to the plasma induced current. The probability of thicker dielectrics getting damaged during the plasma process is therefore high. For given plasma conditions and gate dielectric thickness, current collection area (i.e., antenna size) determines the voltage buildup across the gate dielectric. Damage probability increases with the size of the

  2. Protective Effects of the Mushroom Lactarius deterrimus Extract on Systemic Oxidative Stress and Pancreatic Islets in Streptozotocin-Induced Diabetic Rats

    PubMed Central

    Mihailović, Mirjana; Arambašić Јovanović, Jelena; Uskoković, Aleksandra; Grdović, Nevena; Dinić, Svetlana; Vidović, Senka; Poznanović, Goran; Mujić, Ibrahim; Vidaković, Melita

    2015-01-01

    The aim of this study was to assess the in vivo effects of the extract of the medicinal mushroom, Lactarius deterrimus, when administered (60 mg/kg, i.p.) daily for four weeks to streptozotocin- (STZ-) induced diabetic rats. Diabetic rats treated with the L. deterrimus extract displayed several improved biochemical parameters in the circulation: reduced hyperglycemia, lower triglyceride concentration and reduced glycated hemoglobin, glycated serum protein, and advanced glycation end product (AGE) levels. This treatment also adjusted the diabetes-induced redox imbalance. Thus, higher activities of the antioxidative enzymes, superoxide dismutase, and catalase in the circulation were accompanied by increased levels of free intracellular thiols and glutathionylated proteins after treatment with the L. deterrimus extract. In addition to a systemic antioxidant effect, the administration of the extract to diabetic rats also had a positive localized effect on pancreatic islets where it decreased AGE formation, and increased the expression of chemokine CXCL12 protein that mediates the restoration of β-cell population through the activation of the serine/threonine-specific Akt protein kinase prosurvival pathway. As a result, the numbers of proliferating cell nuclear antigen- (PCNA-) and insulin-positive β-cells were increased. These results show that the ability of the L. deterrimus extract to alleviate oxidative stress and increase β-cell mass represents a therapeutic potential for diabetes management. PMID:26221612

  3. Contribution of endogenous and exogenous damage to the total radiation-induced damage in the bacterial spore

    SciTech Connect

    Jacobs, G.P.; Samuni, A.; Czapski, G.

    1980-01-01

    Radical scavengers such as polyethylene glycol 4000 and bovine albumin have been used to define the contribution of exogenous and endogenous damage to the total radiation-induced damage in aqueous buffered suspensions of Bacillus pumilus spores. The results indicate that this damage in the bacterial spore is predominantly endogenous.

  4. Insulin-like Growth Factor 2 Overexpression Induces β-Cell Dysfunction and Increases Beta-cell Susceptibility to Damage*

    PubMed Central

    Casellas, Alba; Mallol, Cristina; Salavert, Ariana; Jimenez, Veronica; Garcia, Miquel; Agudo, Judith; Obach, Mercè; Haurigot, Virginia; Vilà, Laia; Molas, Maria; Lage, Ricardo; Morró, Meritxell; Casana, Estefania; Ruberte, Jesús; Bosch, Fatima

    2015-01-01

    The human insulin-like growth factor 2 (IGF2) and insulin genes are located within the same genomic region. Although human genomic studies have demonstrated associations between diabetes and the insulin/IGF2 locus or the IGF2 mRNA-binding protein 2 (IGF2BP2), the role of IGF2 in diabetes pathogenesis is not fully understood. We previously described that transgenic mice overexpressing IGF2 specifically in β-cells (Tg-IGF2) develop a pre-diabetic state. Here, we characterized the effects of IGF2 on β-cell functionality. Overexpression of IGF2 led to β-cell dedifferentiation and endoplasmic reticulum stress causing islet dysfunction in vivo. Both adenovirus-mediated overexpression of IGF2 and treatment of adult wild-type islets with recombinant IGF2 in vitro further confirmed the direct implication of IGF2 on β-cell dysfunction. Treatment of Tg-IGF2 mice with subdiabetogenic doses of streptozotocin or crossing these mice with a transgenic model of islet lymphocytic infiltration promoted the development of overt diabetes, suggesting that IGF2 makes islets more susceptible to β-cell damage and immune attack. These results indicate that increased local levels of IGF2 in pancreatic islets may predispose to the onset of diabetes. This study unravels an unprecedented role of IGF2 on β-cells function. PMID:25971976

  5. Insulin-like Growth Factor 2 Overexpression Induces β-Cell Dysfunction and Increases Beta-cell Susceptibility to Damage.

    PubMed

    Casellas, Alba; Mallol, Cristina; Salavert, Ariana; Jimenez, Veronica; Garcia, Miquel; Agudo, Judith; Obach, Mercè; Haurigot, Virginia; Vilà, Laia; Molas, Maria; Lage, Ricardo; Morró, Meritxell; Casana, Estefania; Ruberte, Jesús; Bosch, Fatima

    2015-07-03

    The human insulin-like growth factor 2 (IGF2) and insulin genes are located within the same genomic region. Although human genomic studies have demonstrated associations between diabetes and the insulin/IGF2 locus or the IGF2 mRNA-binding protein 2 (IGF2BP2), the role of IGF2 in diabetes pathogenesis is not fully understood. We previously described that transgenic mice overexpressing IGF2 specifically in β-cells (Tg-IGF2) develop a pre-diabetic state. Here, we characterized the effects of IGF2 on β-cell functionality. Overexpression of IGF2 led to β-cell dedifferentiation and endoplasmic reticulum stress causing islet dysfunction in vivo. Both adenovirus-mediated overexpression of IGF2 and treatment of adult wild-type islets with recombinant IGF2 in vitro further confirmed the direct implication of IGF2 on β-cell dysfunction. Treatment of Tg-IGF2 mice with subdiabetogenic doses of streptozotocin or crossing these mice with a transgenic model of islet lymphocytic infiltration promoted the development of overt diabetes, suggesting that IGF2 makes islets more susceptible to β-cell damage and immune attack. These results indicate that increased local levels of IGF2 in pancreatic islets may predispose to the onset of diabetes. This study unravels an unprecedented role of IGF2 on β-cells function. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Size-based separation and collection of mouse pancreatic islets for functional analysis.

    PubMed

    Nam, Ki-Hwan; Yong, Wang; Harvat, Tricia; Adewola, Adeola; Wang, Shesun; Oberholzer, Jose; Eddington, David T

    2010-10-01

    Islet size has recently been demonstrated to be an important factor in determining human islet transplantation outcomes. In this study, a multi-layered microfluidic device was developed and quantified for size-based separation of a heterogeneous population of mouse islets. The device was fabricated using standard soft lithography and polydimethylsiloxane (PDMS). Size-based separation was first demonstrated via injection of a heterogeneous population of glass beads between 50-300 microm in diameter which were separated into five sub-populations based on their diameter. Next, a heterogeneous population of mouse pancreatic islets, between 50-250 microm in diameter was separated into four sub-populations. Throughout this process the islets remained intact without any signs of damage, as indicated by cell viability staining. Islet glucose-stimulated insulin secretion of each sub-population of islets was also evaluated demonstrating that islets smaller than 150 microm have superior stimulation indexes (SI) compared to islets larger than 150 microm. In this study, we found that islets between 100 microm and 150 microm in diameter had the greatest SI value in a heterogeneous population of islets.

  7. Cellular senescence determines endothelial cell damage induced by uremia.

    PubMed

    Carracedo, Julia; Buendía, Paula; Merino, Ana; Soriano, Sagrario; Esquivias, Elvira; Martín-Malo, Alejandro; Aljama, Pedro; Ramírez, Rafael

    2013-08-01

    Renal dysfunction is closely associated with endothelial damage leading to cardiovascular disease. However, the extent to which endothelial damage induced by uremia is modulated by aging is poorly known. Aging can render endothelial cells more susceptible to apoptosis through an oxidative stress-dependent pathway. We examined whether senescence-associated to oxidative stress determines the injury induced by the uremia in endothelial cells. Human umbilical vein endothelial cells (HUVEC) was incubated with human uremic serum and, in the animal model, endothelial cells were obtained from aortas of uremic and no uremic rats. Vitamin C was used to prevent oxidative stress. Senescence, assessed by telomere length and enzyme-betagalactosidase (β-gal), reactive oxygen species (ROS), mitochondrial depolarization (JC-1 probe), caspase 3, and apoptosis were determined by flow cytometry. NF-κB activity was determined by Western blot. Uremic serum increased ROS and NF-κB in young and aging HUVEC. However only in aging cells, uremic serum induced apoptosis (vs young HUVEC, p<0.01). The endothelial damage induced by uremia seems to be related with the increased oxidative stress, since in both HUVEC and in the experimental model of renal disease in rats, vitamin C prevents endothelial apoptosis. However, vitamin C did not decrease the oxidative stress associated to senescence. These results showed that as compared with young cells, senescent cells have high sensitivity to damage associated to the oxidative stress induced by the uremia. Consequently, protecting senescent endothelial cells from increased oxidative stress might be an effective therapeutic approach in the treatment of vascular disorders in chronic kidney diseases. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Radiation-induced DNA damage and chromatin structure

    NASA Technical Reports Server (NTRS)

    Rydberg, B.; Chatterjee, A. (Principal Investigator)

    2001-01-01

    DNA lesions induced by ionizing radiation in cells are clustered and not randomly distributed. For low linear energy transfer (LET) radiation this clustering occurs mainly on the small scales of DNA molecules and nucleosomes. For example, experimental evidence suggests that both strands of DNA on the nucleosomal surface can be damaged in single events and that this damage occurs with a 10-bp modulation because of protection by histones. For high LET radiation, clustering also occurs on a larger scale and depends on chromatin organization. A particularly significant clustering occurs when an ionizing particle traverses the 30 nm chromatin fiber with generation of heavily damaged DNA regions with an average size of about 2 kbp. On an even larger scale, high LET radiation can produce several DNA double-strand breaks in closer proximity than expected from randomness. It is suggested that this increases the probability of misrejoining of DNA ends and generation of lethal chromosome aberrations.

  9. Multiomic Analysis of the UV-Induced DNA Damage Response.

    PubMed

    Boeing, Stefan; Williamson, Laura; Encheva, Vesela; Gori, Ilaria; Saunders, Rebecca E; Instrell, Rachael; Aygün, Ozan; Rodriguez-Martinez, Marta; Weems, Juston C; Kelly, Gavin P; Conaway, Joan W; Conaway, Ronald C; Stewart, Aengus; Howell, Michael; Snijders, Ambrosius P; Svejstrup, Jesper Q

    2016-05-11

    In order to facilitate the identification of factors and pathways in the cellular response to UV-induced DNA damage, several descriptive proteomic screens and a functional genomics screen were performed in parallel. Numerous factors could be identified with high confidence when the screen results were superimposed and interpreted together, incorporating biological knowledge. A searchable database, bioLOGIC, which provides access to relevant information about a protein or process of interest, was established to host the results and facilitate data mining. Besides uncovering roles in the DNA damage response for numerous proteins and complexes, including Integrator, Cohesin, PHF3, ASC-1, SCAF4, SCAF8, and SCAF11, we uncovered a role for the poorly studied, melanoma-associated serine/threonine kinase 19 (STK19). Besides effectively uncovering relevant factors, the multiomic approach also provides a systems-wide overview of the diverse cellular processes connected to the transcription-related DNA damage response.

  10. Investigation of the laser-induced damage of dispersive coatings

    NASA Astrophysics Data System (ADS)

    Angelov, Ivan B.; von Conta, Aaron; Trushin, Sergei A.; Major, Zsuzsanna; Karsch, Stefan; Krausz, Ferenc; Pervak, Vladimir

    2011-12-01

    Different dispersive coatings were tested in terms of laser-induced damage threshold by using a Ti:Sapphire laser yielding 1 mJ, 30 fs pulses at 500 Hz repetition rate at 790 nm central wavelength. The beam was focused down to 140 μm. Single layer coatings of Au, Ag, Nb2O5, SiO2, Ta2O5 and mixtures of Ta2O5 and silica were examined as well as different dispersive coatings. We observed a direct dependence of the damage threshold on the band gap of the materials used to produce the different samples. The damage threshold values for the dispersive coatings employing the same high index material lay within a range of 30% of each other.

  11. Radiation-induced DNA damage and chromatin structure

    NASA Technical Reports Server (NTRS)

    Rydberg, B.; Chatterjee, A. (Principal Investigator)

    2001-01-01

    DNA lesions induced by ionizing radiation in cells are clustered and not randomly distributed. For low linear energy transfer (LET) radiation this clustering occurs mainly on the small scales of DNA molecules and nucleosomes. For example, experimental evidence suggests that both strands of DNA on the nucleosomal surface can be damaged in single events and that this damage occurs with a 10-bp modulation because of protection by histones. For high LET radiation, clustering also occurs on a larger scale and depends on chromatin organization. A particularly significant clustering occurs when an ionizing particle traverses the 30 nm chromatin fiber with generation of heavily damaged DNA regions with an average size of about 2 kbp. On an even larger scale, high LET radiation can produce several DNA double-strand breaks in closer proximity than expected from randomness. It is suggested that this increases the probability of misrejoining of DNA ends and generation of lethal chromosome aberrations.

  12. Stellate Cells Orchestrate Concanavalin A-Induced Acute Liver Damage.

    PubMed

    Rani, Richa; Tandon, Ashish; Wang, Jiang; Kumar, Sudhir; Gandhi, Chandrashekhar R

    2017-09-01

    Concanavalin A (ConA) causes immune cell-mediated liver damage, but the contribution of resident nonparenchymal cells (NPCs) is also evident. Hepatic stellate cells (HSCs) induce hepatic inflammation and immunological reactions; we therefore investigated their role in ConA-induced liver injury. ConA was administered i.v. to control or HSC-depleted mice; hepatic histopathology and cytokines/chemokines were determined after 6 hours. In vitro, effects of ConA-conditioned HSC medium on hepatocytes were determined. ConA induced inflammation, sinusoidal congestion, and extensive midzonal hepatocyte death in control mice, which were strongly minimized in HSC-depleted mice. CD4 and natural killer T cells and neutrophils were markedly reduced in ConA-treated HSC-depleted mice compared with control mice. The increase in cytokines/chemokines of hepatic injury was much higher in ConA-treated control mice than in HSC-depleted mice. ConA-treated HSCs showed increased expression of interferon-β, tumor necrosis factor-α, and CXCL1, induced oxidative stress in hepatocytes, and caused hepatocyte apoptosis. ConA induced nuclear translocation of interferon-regulatory factor-1 (IRF1) in hepatocytes in vivo, and ConA/HSC induced a similar effect in cultured hepatocytes. IRF1-knockout mice were resistant to ConA-induced liver damage, and anti-interferon β antibody mitigated ConA/HSC-induced injury. In HSC-NPC co-culture, ConA-induced expression of inflammatory cytokines/chemokines was significantly augmented compared with NPCs alone. HSCs play an essential role in ConA-induced liver injury directly via the interferon-β/IRF1 axis, and by modulating properties of NPCs. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  13. Automated separation of merged Langerhans islets

    NASA Astrophysics Data System (ADS)

    Švihlík, Jan; Kybic, Jan; Habart, David

    2016-03-01

    This paper deals with separation of merged Langerhans islets in segmentations in order to evaluate correct histogram of islet diameters. A distribution of islet diameters is useful for determining the feasibility of islet transplantation in diabetes. First, the merged islets at training segmentations are manually separated by medical experts. Based on the single islets, the merged islets are identified and the SVM classifier is trained on both classes (merged/single islets). The testing segmentations were over-segmented using watershed transform and the most probable back merging of islets were found using trained SVM classifier. Finally, the optimized segmentation is compared with ground truth segmentation (correctly separated islets).

  14. Deletion of GPR40 Impairs Glucose-Induced Insulin Secretion In Vivo in Mice Without Affecting Intracellular Fuel Metabolism in Islets

    PubMed Central

    Alquier, Thierry; Peyot, Marie-Line; Latour, Martin G.; Kebede, Melkam; Sorensen, Christina M.; Gesta, Stephane; Ronald Kahn, C.; Smith, Richard D.; Jetton, Thomas L.; Metz, Thomas O.; Prentki, Marc; Poitout, Vincent

    2009-01-01

    OBJECTIVE The G-protein–coupled receptor GPR40 mediates fatty acid potentiation of glucose-stimulated insulin secretion, but its contribution to insulin secretion in vivo and mechanisms of action remain uncertain. This study was aimed to ascertain whether GPR40 controls insulin secretion in vivo and modulates intracellular fuel metabolism in islets. RESEARCH DESIGN AND METHODS Insulin secretion and sensitivity were assessed in GPR40 knockout mice and their wild-type littermates by hyperglycemic clamps and hyperinsulinemic euglycemic clamps, respectively. Transcriptomic analysis, metabolic studies, and lipid profiling were used to ascertain whether GPR40 modulates intracellular fuel metabolism in islets. RESULTS Both glucose- and arginine-stimulated insulin secretion in vivo were decreased by ∼60% in GPR40 knockout fasted and fed mice, without changes in insulin sensitivity. Neither gene expression profiles nor intracellular metabolism of glucose and palmitate in isolated islets were affected by GPR40 deletion. Lipid profiling of isolated islets revealed that the increase in triglyceride and decrease in lyso-phosphatidylethanolamine species in response to palmitate in vitro was similar in wild-type and knockout islets. In contrast, the increase in intracellular inositol phosphate levels observed in wild-type islets in response to fatty acids in vitro was absent in knockout islets. CONCLUSIONS These results indicate that deletion of GPR40 impairs insulin secretion in vivo not only in response to fatty acids but also to glucose and arginine, without altering intracellular fuel metabolism in islets, via a mechanism that may involve the generation of inositol phosphates downstream of GPR40 activation. PMID:19720802

  15. Commercially Available Gas-Permeable Cell Culture Bags May Not Prevent Anoxia in Cultured or Shipped Islets

    PubMed Central

    Avgoustiniatos, E.S.; Hering, B.J.; Rozak, P.R.; Wilson, J.R.; Tempelman, L.A.; Balamurugan, A.N.; Welch, D.P.; Weegman, B.P.; Suszynski, T.M.; Papas, K.K.

    2009-01-01

    Prolonged anoxia has deleterious effects on islets. Gas-permeable cell culture devices can be used to minimize anoxia during islet culture and especially during shipment when elimination of gas-liquid interfaces is required to prevent the formation of damaging gas bubbles. Gas-permeable bags may have several drawbacks, such as propensity for puncture and contamination, difficult islet retrieval, and significantly lower oxygen permeability than silicone rubber membranes (SRM). We hypothesized that oxygen permeability of bags may be insufficient for islet oxygenation. We measured oxygen transmission rates through the membrane walls of three different types of commercially available bags and through SRM currently used for islet shipment. We found that the bag membranes have oxygen transmission rates per unit area about 100-fold lower than SRM. We solved the oxygen diffusion-reaction equation for 150-μm diameter islets seeded at 3000 islet equivalents per cm2, a density adequate to culture and ship an entire human or porcine islet preparation in a single gas-permeable device, predicting that about 40% of the islet volume would be anoxic at 22°C and about 70% would be anoxic at 37°C. Islets of larger size or islets accumulated during shipment would be even more anoxic. The model predicted no anoxia in islets similarly seeded in devices with SRM bottoms. We concluded that commercially available bags may not prevent anoxia during islet culture or shipment; devices with SRM bottoms are more suitable alternatives. PMID:18374080

  16. Prediction of marginal mass required for successful islet transplantation.

    PubMed

    Papas, Klearchos K; Colton, Clark K; Qipo, Andi; Wu, Haiyan; Nelson, Rebecca A; Hering, Bernhard J; Weir, Gordon C; Koulmanda, Maria

    2010-02-01

    Islet quality assessment methods for predicting diabetes reversal (DR) following transplantation are needed. We investigated two islet parameters, oxygen consumption rate (OCR) and OCR per DNA content, to predict transplantation outcome and explored the impact of islet quality on marginal islet mass for DR. Outcomes in immunosuppressed diabetic mice were evaluated by transplanting mixtures of healthy and purposely damaged rat islets for systematic variation of OCR/DNA over a wide range. The probability of DR increased with increasing transplanted OCR and OCR/DNA. On coordinates of OCR versus OCR/DNA, data fell into regions in which DR occurred in all, some, or none of the animals with a sharp threshold of around 150-nmol/min mg DNA. A model incorporating both parameters predicted transplantation outcome with sensitivity and specificity of 93% and 94%, respectively. Marginal mass was not constant, depended on OCR/DNA, and increased from 2,800 to over 100,000 islet equivalents/kg body weight as OCR/DNA decreased. We conclude that measurements of OCR and OCR/DNA are useful for predicting transplantation outcome in this model system, and OCR/DNA can be used to estimate the marginal mass required for reversing diabetes. Because human clinical islet preparations in a previous study had OCR/DNA.

  17. Statistical analysis of vibration-induced bone and joint damages.

    PubMed

    Schenk, T

    1995-01-01

    Vibration-induced damages to bones and joints are still occupational diseases with insufficient knowledge about causing and moderating factors and resulting damages. For a better understanding of these relationships also retrospective analyses of already acknowledged occupational diseases may be used. Already recorded detailed data for 203 in 1970 to 1979 acknowledged occupational diseases in the building industry and the building material industry of the GDR are the basis for the here described investigations. The data were gathered from the original documents of the occupational diseases and scaled in cooperation of an industrial engineer and an industrial physician. For the purposes of this investigations the data are to distinguish between data which describe the conditions of the work place (e.g. material, tools and posture), the exposure parameters (e.g. beginning of exposure and latency period) and the disease (e.g. anamnestical and radiological data). These data are treated for the use with sophisticated computerized statistical methods. The following analyses were carried out. Investigation of the connections between the several characteristics, which describe the occupational disease (health damages), including the comparison of the severity of the damages at the individual joints. Investigation of the side dependence of the damages. Investigation of the influence of the age at the beginning of the exposure and the age at the acknowledgement of the occupational disease and herewith of the exposure duration. Investigation of the effect of different occupational and exposure conditions.

  18. Mechanisms for microvascular damage induced by ultrasound-activated microbubbles

    SciTech Connect

    Chen Hong; Brayman, Andrew A.; Evan, Andrew P.; Matula, Thomas J.

    2012-10-03

    To provide insight into the mechanisms of microvascular damage induced by ultrasound-activated microbubbles, experimental studies were performed to correlate microvascular damage to the dynamics of bubble-vessel interactions. High-speed photomicrography was used to record single microbubbles interacting with microvessels in ex vivo tissue, under the exposure of short ultrasound pulses with a center frequency of 1 MHz and peak negative pressures (PNP) ranging from 0.8-4 MPa. Vascular damage associated with observed bubble-vessel interactions was either indicated directly by microbubble extravasation or examined by transmission electron microscopy (TEM) analyses. As observed previously, the high-speed images revealed that ultrasound-activated microbubbles could cause distention and invagination of adjacent vessel walls, and could form liquid jets in microvessels. Vessel distention, invagination, and liquid jets were associated with the damage of microvessels whose diameters were smaller than those of maximally expanded microbubbles. However, vessel invagination appeared to be the dominant mechanism for the damage of relative large microvessels.

  19. Recombinant Reg3β protein protects against streptozotocin-induced β-cell damage and diabetes

    PubMed Central

    Luo, Chen; Yu, Lu-Ting; Yang, Meng-Qi; Li, Xiang; Zhang, Zhi-Yuan; Alfred, Martin O; Liu, Jun-Li; Wang, Min

    2016-01-01

    Regenerating genes (Reg) have been found during the search for factors involved in pancreatic islet regeneration. Our recent study discovered that pancreatic β-cell-specific overexpression of Reg3β protects against streptozotocin (Stz) -induced diabetes in mice. To investigate its potential roles in the treatment of diabetes, we produced a recombinant Reg3β protein and provided evidence that it is active in promoting islet β-cell survival against Stz- triggered cell death. Though ineffective in alleviating preexisting diabetes, pretreatment of recombinant Reg3β was capable of minimizing the Stz-induced hyperglycemia and weight loss, by preserving serum and pancreatic insulin levels, and islet β-cell mass. No obvious changes were observed in the rate of cell proliferation and hypertrophy in α- or acinar-cells after treatment with recombinant Reg3β. The underlying mechanism of Reg3β-mediated protection seems to involve Akt activation which upregulates Bcl-2 and Bcl-xL levels and consequently promotes cell survival. PMID:27767186

  20. Leptin Administration Enhances Islet Transplant Performance in Diabetic Mice

    PubMed Central

    Denroche, Heather C.; Quong, Whitney L.; Bruin, Jennifer E.; Tudurí, Eva; Asadi, Ali; Glavas, Maria M.; Fox, Jessica K.; Kieffer, Timothy J.

    2013-01-01

    Islet transplantation is an effective method to obtain long-term glycemic control for patients with type 1 diabetes, yet its widespread use is limited by an inadequate supply of donor islets. The hormone leptin has profound glucose-lowering and insulin-sensitizing action in type 1 diabetic rodent models. We hypothesized that leptin administration could reduce the dose of transplanted islets required to achieve metabolic control in a mouse model of type 1 diabetes. We first performed a leptin dose-response study in C57Bl/6 mice with streptozotocin (STZ)-induced diabetes to determine a leptin dose insufficient to reverse hyperglycemia. Subsequently, we compared the ability of suboptimal islet transplants of 50 or 125 syngeneic islets to achieve glycemic control in STZ-induced diabetic C57Bl/6 mice treated with or without this dose of leptin. The dose-response study revealed that leptin reverses STZ-induced diabetes in a dose-dependent manner. Supraphysiological leptin levels were necessary to restore euglycemia but simultaneously increased risk of hypoglycemia, and also lost efficacy after 12 days of administration. In contrast, 1 µg/day leptin only modestly reduced blood glucose but maintained efficacy throughout the study duration. We then administered 1 µg/day leptin to diabetic mice that underwent transplantation of 50 or 125 islets. Although these islet doses were insufficient to ameliorate hyperglycemia alone, coadministration of leptin with islet transplantation robustly improved control of glucose and lipid metabolism, without increasing circulating insulin levels. This study reveals that low-dose leptin administration can reduce the number of transplanted islets required to achieve metabolic control in STZ-induced diabetic mice. PMID:23656888

  1. Reformulated meat products protect against ischemia-induced cardiac damage.

    PubMed

    Asensio-Lopez, M C; Lax, A; Sanchez-Mas, J; Avellaneda, A; Planes, J; Pascual-Figal, D A

    2016-02-01

    The protective effects of the antioxidants present in food are of great relevance for cardiovascular health. This study evaluates whether the extracts from reformulated meat products with a reduction in fat and/or sodium content exert a cardioprotective effect against ischemia-induced oxidative stress in cardiomyocytes, compared with non-meat foods. Ischemic damage caused loss of cell viability, increased reactive oxygen species and lipid peroxidation and decreased the antioxidant activity. Pretreatment for 24 h with digested or non-digested extracts from reformulated meat products led to protection against ischemia-induced oxidative damage: increased cell viability, reduced oxidative stress and restored the antioxidant activity. Similar results were obtained using extracts from tuna fish, but not with the extracts of green peas, salad or white beans. These results suggest that reformulated meat products have a beneficial impact in protecting cardiac cells against ischemia, and they may represent a source of natural antioxidants with benefits for cardiovascular health.

  2. Laser Induced Retinal Damage Thresholds for Annular Retinal Beam Profiles

    DTIC Science & Technology

    2004-01-01

    Thompson-Gerstman granular model of laser-induced thermal damage to the retina ."°20 The study documented in this paper is a continuation of our earlier...Retinal Beam Profiles DISTRIBUTION: Approved for public release, distribution unlimited This paper is part of the following report: TITLE: Laser Interaction...mrad of visual field; which correspond to outer beam diameters of roughly 70, 160, and 300 tin, respectively, on the primate retina . Annular beam

  3. The effect of insulin treatment and of islet transplantation on the resistance artery function in the STZ-induced diabetic rat.

    PubMed Central

    Heygate, K. M.; Davies, J.; Holmes, M.; James, R. F.; Thurston, H.

    1996-01-01

    1. This study was designed to investigate the influence of insulin treatment and islet transplantation on the smooth muscle contractility and endothelium-dependent and independent relaxation of resistance arteries in the chemically induced streptozotocin (STZ) diabetic rat after 6-8 weeks, and 12-14 weeks of diabetes, compared to non-diabetic age-matched controls. 2. The morphology, and contractile responses to high potassium physiological salt solution (KPSS), KPSS containing 10(-5) M noradrenaline (NAK), and concentration-response curves to noradrenaline (NA) of mesenteric resistance arteries were recorded, along with the endothelium-dependent relaxation responses to acetylcholine (ACh) and bradykinin (BK), and endothelium-independent relaxation to sodium nitroprusside (SNP). Concentration-response curves were then repeated in the presence of a nitric oxide synthase inhibitor, NG-nitro-L-arginine (L-NOARG). 3. Insulin-treated diabetic rats in the 12 week study demonstrated enhanced vascular contractility to KPSS, NAK and NA, compared to age-matched non-diabetic controls. 4. Incubation with L-NOARG resulted in both a significant increase in maximum contractile response, and sensitivity (pD2) to NA in the untreated diabetic group (6 weeks). A significant shift in sensitivity was also seen in the insulin-treated diabetic group. In the 12 week study, incubation with L-NOARG resulted in an increased maximum contractile response and sensitivity to NA in the insulin-treated diabetics. An increase in sensitivity was also observed in the untreated diabetic group. 5. Endothelium-dependent relaxation to ACh was significantly augmented in the untreated diabetics (6-weeks), compared to the control group. In the 12-week study, relaxation to both ACh and BK was not significantly different in any of the experimental groups when compared to the sham-operated non-diabetic controls. 6. Incubation with L-NOARG resulted in a significant attenuation of the maximum relaxation response

  4. Stochastics of diffusion induced damage in intercalation materials

    NASA Astrophysics Data System (ADS)

    Barai, Pallab; Mukherjee, Partha P.

    2016-10-01

    Fundamental understanding of the underlying diffusion-mechanics interplay in the intercalation electrode materials is critical toward improved life and performance of lithium-ion batteries for electric vehicles. Especially, diffusion induced microcrack formation in brittle, intercalation active materials, with emphasis on the grain/grain-boundary (GB) level implications, has been fundamentally investigated based on a stochastic modeling approach. Quasistatic damage evolution has been analyzed under lithium concentration gradient induced stress. Scaling of total amount of microcrack formation shows a power law variation with respect to the system size. Difference between the global and local roughness exponent indicates the existence of anomalous scaling. The deterioration of stiffness with respect to microcrack density displays two distinct regions of damage propagation; namely, diffused damage evolution and stress concentration driven localized crack propagation. Polycrystalline material microstructures with different grain sizes have been considered to study the diffusion-induced fracture in grain and GB regions. Intergranular crack paths are observed within microstructures containing softer GB region, whereas, transgranular crack paths have been observed in microstructures with relatively strong GB region. Increased tortuosity of the spanning crack has been attributed as the reason behind attaining increased fracture strength in polycrystalline materials with smaller grain sizes.

  5. Phosphoinositide 3-kinase inhibitors induce DNA damage through nucleoside depletion

    PubMed Central

    Juvekar, Ashish; Hu, Hai; Yadegarynia, Sina; Lyssiotis, Costas A.; Ullas, Soumya; Lien, Evan C.; Bellinger, Gary; Son, Jaekyoung; Hok, Rosanna C.; Seth, Pankaj; Daly, Michele B.; Kim, Baek; Scully, Ralph; Asara, John M.; Cantley, Lewis C.; Wulf, Gerburg M.

    2016-01-01

    We previously reported that combining a phosphoinositide 3-kinase (PI3K) inhibitor with a poly-ADP Rib polymerase (PARP)-inhibitor enhanced DNA damage and cell death in breast cancers that have genetic aberrations in BRCA1 and TP53. Here, we show that enhanced DNA damage induced by PI3K inhibitors in this mutational background is a consequence of impaired production of nucleotides needed for DNA synthesis and DNA repair. Inhibition of PI3K causes a reduction in all four nucleotide triphosphates, whereas inhibition of the protein kinase AKT is less effective than inhibition of PI3K in suppressing nucleotide synthesis and inducing DNA damage. Carbon flux studies reveal that PI3K inhibition disproportionately affects the nonoxidative pentose phosphate pathway that delivers Rib-5-phosphate required for base ribosylation. In vivo in a mouse model of BRCA1-linked triple-negative breast cancer (K14-Cre BRCA1f/fp53f/f), the PI3K inhibitor BKM120 led to a precipitous drop in DNA synthesis within 8 h of drug treatment, whereas DNA synthesis in normal tissues was less affected. In this mouse model, combined PI3K and PARP inhibition was superior to either agent alone to induce durable remissions of established tumors. PMID:27402769

  6. Inflammation-Induced Cell Proliferation Potentiates DNA Damage-Induced Mutations In Vivo

    PubMed Central

    Kiraly, Orsolya; Gong, Guanyu; Olipitz, Werner; Muthupalani, Sureshkumar; Engelward, Bevin P.

    2015-01-01

    Mutations are a critical driver of cancer initiation. While extensive studies have focused on exposure-induced mutations, few studies have explored the importance of tissue physiology as a modulator of mutation susceptibility in vivo. Of particular interest is inflammation, a known cancer risk factor relevant to chronic inflammatory diseases and pathogen-induced inflammation. Here, we used the fluorescent yellow direct repeat (FYDR) mice that harbor a reporter to detect misalignments during homologous recombination (HR), an important class of mutations. FYDR mice were exposed to cerulein, a potent inducer of pancreatic inflammation. We show that inflammation induces DSBs (γH2AX foci) and that several days later there is an increase in cell proliferation. While isolated bouts of inflammation did not induce HR, overlap between inflammation-induced DNA damage and inflammation-induced cell proliferation induced HR significantly. To study exogenously-induced DNA damage, animals were exposed to methylnitrosourea, a model alkylating agent that creates DNA lesions relevant to both environmental exposures and cancer chemotherapy. We found that exposure to alkylation damage induces HR, and importantly, that inflammation-induced cell proliferation and alkylation induce HR in a synergistic fashion. Taken together, these results show that, during an acute bout of inflammation, there is a kinetic barrier separating DNA damage from cell proliferation that protects against mutations, and that inflammation-induced cell proliferation greatly potentiates exposure-induced mutations. These studies demonstrate a fundamental mechanism by which inflammation can act synergistically with DNA damage to induce mutations that drive cancer and cancer recurrence. PMID:25647331

  7. Glucose- and GTP-dependent stimulation of the carboxyl methylation of CDC42 in rodent and human pancreatic islets and pure beta cells. Evidence for an essential role of GTP-binding proteins in nutrient-induced insulin secretion.

    PubMed Central

    Kowluru, A; Seavey, S E; Li, G; Sorenson, R L; Weinhaus, A J; Nesher, R; Rabaglia, M E; Vadakekalam, J; Metz, S A

    1996-01-01

    Several GTP-binding proteins (G-proteins) undergo post-translational modifications (isoprenylation and carboxyl methylation) in pancreatic beta cells. Herein, two of these were identified as CDC42 and rap 1, using Western blotting and immunoprecipitation. Confocal microscopic data indicated that CDC42 is localized only in islet endocrine cells but not in acinar cells of the pancreas. CDC42 undergoes a guanine nucleotide-specific membrane association and carboxyl methylation in normal rat islets, human islets, and pure beta (HIT or INS-1) cells. GTPgammaS-dependent carboxyl methylation of a 23-kD protein was also demonstrable in secretory granule fractions from normal islets or beta cells. AFC (a specific inhibitor of prenyl-cysteine carboxyl methyl transferases) blocked the carboxyl methylation of CDC42 in five types of insulin-secreting cells, without blocking GTPgammaS-induced translocation, implying that methylation is a consequence (not a cause) of transfer to membrane sites. High glucose (but not a depolarizing concentration of K+) induced the carboxyl methylation of CDC42 in intact cells, as assessed after specific immunoprecipitation. This effect was abrogated by GTP depletion using mycophenolic acid and was restored upon GTP repletion by coprovision of guanosine. In contrast, although rap 1 was also carboxyl methylated, it was not translocated to the particulate fraction by GTPgammaS; furthermore, its methylation was also stimulated by 40 mM K+ (suggesting a role which is not specific to nutrient stimulation). AFC also impeded nutrient-induced (but not K+-induced) insulin secretion from islets and beta cells under static or perifusion conditions, whereas an inactive structural analogue of AFC failed to inhibit insulin release. These effects were reproduced not only by S-adenosylhomocysteine (another methylation inhibitor), but also by GTP depletion. Thus, the glucose- and GTP-dependent carboxyl methylation of G-proteins such as CDC42 is an obligate step in

  8. Multipotent mesenchymal stromal cells enhance insulin secretion from human islets via N-cadherin interaction and prolong function of transplanted encapsulated islets in mice.

    PubMed

    Montanari, Elisa; Meier, Raphael P H; Mahou, Redouan; Seebach, Jörg D; Wandrey, Christine; Gerber-Lemaire, Sandrine; Buhler, Leo H; Gonelle-Gispert, Carmen

    2017-09-29

    Multipotent mesenchymal stromal cells (MSC) enhance viability and function of islets of Langerhans. We aimed to examine the interactions between human MSC and human islets of Langerhans that influence the function of islets. Human MSC and human islets (or pseudoislets, obtained after digestion and reaggregation of islet cells) were cocultured with or without cellular contact and glucose-stimulated insulin secretion assays were performed to assess cell function. The expression of several adhesion molecules, notably ICAM-1 and N-cadherin on islets and MSC, was investigated by qPCR. The role of N-cadherin was analyzed by adding an anti-N-cadherin antibody in islets cultured with or without MSC for 24 h followed by insulin measurements in static incubation assays. Islets and MSC were coencapsulated in new hydrogel microspheres composed of calcium alginate and covalently crosslinked polyethylene glycol. Encapsulated cells were transplanted intraperitoneally in streptozotocin-induced diabetic mice and glycemia was monitored. Islet function was evaluated by the intraperitoneal glucose tolerance test. In vitro, free islets and pseudoislets cocultured in contact with MSC showed a significantly increased insulin secretion when compared to islets or pseudoislets cultured alone or cocultured without cell-to-cell contact with MSC (p < 0.05). The expression of ICAM-1 and N-cadherin was present on islets and MSC. Blocking N-cadherin prevented the enhanced insulin secretion by islets cultured in contact with MSC whereas it did not affect insulin secretion by islets cultured alone. Upon transplantation in diabetic mice, islets microencapsulated together with MSC showed significantly prolonged normoglycemia when compared with islets alone (median 69 and 39 days, respectively, p < 0.01). The intraperitoneal glucose tolerance test revealed an improved glycemic response in mice treated with islets microencapsulated together with MSC compared to mice transplanted with islets

  9. Enhancement of ultrasonically induced cell damage by phthalocyanines in vitro.

    PubMed

    Milowska, Katarzyna; Gabryelak, Teresa

    2008-12-01

    In this work, erythrocytes from carp were used as a nucleated cell model to test the hypothesis that the phthalocyanines (zinc--ZnPc and chloroaluminium -AlClPc) enhance ultrasonically induced damage in vitro. In order to confirm and complete our earlier investigation, the influence of ultrasound (US) and phthalocyanines (Pcs) on unresearched cellular components, was studied. Red blood cells were exposed to 1 MHz continuous ultrasound wave (0.61 and/or 2.44 W/cm(2)) in the presence or absence of phthalocyanines (3 microM). To identify target cell damage, we studied hemolysis, membrane fluidity and morphology of erythrocytes. To demonstrate the changes in the fluidity of plasma membrane we used the spectrofluorimetric methods using two fluorescence probes: 1-[4-(trimethylamino)phenyl]-6-phenyl-1,3,5,-hexatriene (TMA-DPH) and 1,6-diphenyl-1,3,5-hexatriene (DPH). The effect of US and Pcs on nucleated erythrocytes morphology was estimated on the basis of microscopic observation. The enhancement of ultrasonically induced membrane damage by both phthalocyanines was observed in case of hemolysis, and membrane surface fluidity, in comparison to ultrasound. The authors also observed changes in the morphology of erythrocytes. The obtained results support the hypothesis that the Pcs enhance ultrasonically induced cell damage in vitro. Furthermore, the influence of ultrasound on phthalocyanines (Pcs) in medium and in cells was tested. The authors observed changes in the phthalocyanines absorption spectra in the medium and the increase in the intensity of phthalocyanines fluorescence in the cells. These data can suggest changes in the structure of phthalocyanines after ultrasound action.

  10. Prevention of downhill walking-induced muscle damage by non-damaging downhill walking

    PubMed Central

    Yamamoto, Masayoshi; Kanehisa, Hiroaki; Nosaka, Kazunori

    2017-01-01

    Purpose Mountain trekking involves level, uphill, and downhill walking (DW). Prolonged DW induces damage to leg muscles, reducing force generating ability and muscle coordination. These increase risks for more serious injuries and accidents in mountain trekking, thus a strategy to minimize muscle damage is warranted. It has been shown that low-intensity eccentric contractions confer protective effect on muscle damage induced by high-intensity eccentric contractions. This study tested the hypothesis that 5-min non-damaging DW would attenuate muscle damage induced by 40-min DW, but 5-min level walking (LW) would not. Methods Untrained young men were allocated (n = 12/group) to either a control or one of the two preconditioning groups (PRE-DW or PRE-LW). The PRE-DW and PRE-LW groups performed 5-min DW (-28%) and 5-min LW, respectively, at 5 km/h with a load of 10% body mass, 1 week before 40-min DW (-28%, 5 km/h, 10% load). The control group performed 40-min DW only. Maximal knee extension strength, plasma creatine kinase (CK) activity, and muscle soreness (0–100 mm visual analogue scale) were measured before and 24 h after 5-min DW and 5-min LW, and before and 24, 48, and 72 h after 40-min DW. Results No significant changes in any variables were evident after 5-min DW and 5-min LW. After 40-min DW, the control and PRE-LW groups showed significant (P<0.05) changes in the variables without significant differences between groups (control vs. PRE-LW; peak strength reduction: -19.2 ± 6.9% vs. -18.7 ± 11.0%, peak CK: 635.5 ± 306.0 vs. 639.6 ± 405.4 U/L, peak soreness: 81.4 ± 14.8 vs. 72.0 ± 29.2 mm). These changes were significantly (P<0.05) attenuated (47–64%) for the PRE-DW group (-9.9 ± 9.6%, 339.3 ± 148.4 U/L, 27.8 ± 16.8 mm). Conclusions The results supported the hypothesis and suggest that performing small volume of downhill walking is crucial in preparation for trekking. PMID:28288187

  11. Mechanism of site-specific DNA damage induced by ozone.

    PubMed

    Ito, Kimiko; Inoue, Sumiko; Hiraku, Yusuke; Kawanishi, Shosuke

    2005-08-01

    Ozone has been shown to induce lung tumors in mice. The reactivity of ozone with DNA in an aqueous solution was investigated by a DNA sequencing technique using 32P-labeled DNA fragments. Ozone induced cleavages in the deoxyribose-phosphate backbone of double-stranded DNA, which were reduced by hydroxyl radical scavengers, suggesting the participation of hydroxyl radicals in the cleavages. The ozone-induced DNA cleavages were enhanced with piperidine treatment, which induces cleavages at sites of base modification, but the inhibitory effect of hydroxyl radical scavengers on the piperidine-induced cleavages was limited. Main piperidine-labile sites were guanine and thymine residues. Cleavages at some guanine and thymine residues after piperidine treatment became more predominant with denatured single-stranded DNA. Exposure of calf thymus DNA to ozone resulted in a dose-dependent increase of the 8-oxo-7,8-dihydro-2'-deoxyguanosine formation, which was partially inhibited by hydroxyl radical scavengers. ESR studies using 5,5-dimethylpyrroline-N-oxide (DMPO) showed that aqueous ozone produced the hydroxyl radical adduct of DMPO. In addition, the fluorescein-dependent chemiluminescence was detected during the decomposition of ozone in a buffer solution and the enhancing effect of D2O was observed, suggesting the formation of singlet oxygen. However, no or little enhancing effect of D2O on the ozone-induced DNA damage was observed. These results suggest that DNA backbone cleavages were caused by ozone via the production of hydroxyl radicals, while DNA base modifications were mainly caused by ozone itself and the participation of hydroxyl radicals and/or singlet oxygen in base modifications is small, if any. A possible link of ozone-induced DNA damage to inflammation-associated carcinogenesis as well as air pollution-related carcinogenesis is discussed.

  12. Oxidant-induced DNA damage of target cells.

    PubMed Central

    Schraufstätter, I; Hyslop, P A; Jackson, J H; Cochrane, C G

    1988-01-01

    In this study we examined the leukocytic oxidant species that induce oxidant damage of DNA in whole cells. H2O2 added extracellularly in micromolar concentrations (10-100 microM) induced DNA strand breaks in various target cells. The sensitivity of a specific target cell was inversely correlated to its catalase content and the rate of removal of H2O2 by the target cell. Oxidant species produced by xanthine oxidase/purine or phorbol myristate acetate-stimulated monocytes induced DNA breakage of target cells in proportion to the amount of H2O2 generated. These DNA strand breaks were prevented by extracellular catalase, but not by superoxide dismutase. Cytotoxic doses of HOCl, added to target cells, did not induce DNA strand breakage, and myeloperoxidase added extracellularly in the presence of an H2O2-generating system, prevented the formation of DNA strand breaks in proportion to its H2O2 degrading capacity. The studies also indicated that H2O2 formed hydroxyl radical (.OH) intracellularly, which appeared to be the most likely free radical responsible for DNA damage: .OH was detected in cells exposed to H2O2; the DNA base, deoxyguanosine, was hydroxylated in cells exposed to H2O2; and intracellular iron was essential for induction of DNA strand breaks. PMID:2843565

  13. Acetaldehyde-induced mitochondrial dysfunction sensitizes hepatocytes to oxidative damage.

    PubMed

    Farfán Labonne, Blanca Eugenia; Gutiérrez, Mario; Gómez-Quiroz, Luis Enrique; Konigsberg Fainstein, Mina; Bucio, Leticia; Souza, Verónica; Flores, Oscar; Ortíz, Victor; Hernández, Elizabeth; Kershenobich, David; Gutiérrez-Ruíz, María Concepción

    2009-12-01

    Acetaldehyde (Ac), the main metabolite of ethanol oxidation, is a very reactive compound involved in alcohol-induced liver damage. In the present work, we studied the effect of Ac in mitochondria functionality. Mitochondria from Wistar rats were isolated and treated with Ac. Ac decreased respiratory control by 50% which was associated with a decrease in adenosine triphosphate content (28.5%). These results suggested that Ac could be inducing changes in cell redox status. We determined protein oxidation, superoxide dismutase (SOD) activity, and glutathione ratio, indicating that Ac induced an enhanced oxidation of proteins and a decrease in SOD activity (90%) and glutathione/oxidized GSH ratio (36%). The data suggested that Ac-induced oxidative stress mediated by mitochondria dysfunction can lead to cell sensitization and to a second oxidative challenge. We pretreated hepatocytes with Ac followed by treatment with antimycin A, and this experiment revealed a noticeable decrease in cell viability, determined by neutral red assay, in comparison with cells treated with Ac alone. Our data demonstrate that Ac impairs mitochondria functionality generating oxidative stress that sensitizes cells to a second damaging signal contributing to the development of alcoholic liver disease.

  14. Sunscreens promote repair of ultraviolet radiation-induced dermal damage.

    PubMed

    Kligman, L H; Akin, F J; Kligman, A M

    1983-08-01

    Chronic UV irradiation profoundly damages the dermis of human and animal skin. These alterations were thought to be irreversible. Recently, we showed that substantial repair occurred in hairless mice after stopping UV exposure. A band of new connective tissue was laid down subepidermally. The present study focussed on whether repair would occur if animals were protected by sunscreens after dermal damage was induced and irradiation was continued. Albino hairless mice were exposed to Westinghouse FS20 sunlamps thrice weekly for 30 weeks. The daily dose of UV (UVB + UVA) was 0.17 J/cm2. Sunscreens of sun protection factors (SPF) 6 and 15 were applied after 10 and 20 weeks of irradiation. Biopsies were taken at 10, 20, 30, and 45 weeks of the experiment. With both sunscreens, especially SPF-15, previously damaged dermis was repaired during continued irradiation. Repair occurred in situ and, in severely damaged skin, in the novel form of subepidermal reconstruction zones of new connective tissue with parallel collagen bundles and a network of fine elastic fibers.

  15. Leukocyte involvement in renal reperfusion-induced liver damage.

    PubMed

    Khastar, Hossein; Kadkhodaee, Mehri; Sadeghipour, Hamid Reza; Seifi, Behjat; Hadjati, Jamshid; Delavari, Fatemeh; Soleimani, Manoocher

    2011-01-01

    Renal ischemia-reperfusion (IR) induces organ damage in remote organs. The aim of this study was to assess the role of leukocytes in the induction of liver damage after renal IR injury. Inbred mice were subjected to either sham operation or bilateral renal IR injury (60 min ischemia followed by 3 h reperfusion). Mice were then anesthetized for collection of leukocytes by heart puncture. Isolated leukocytes were transferred to two other groups: intact recipient mice that received leukocytes from IR mice and intact recipient mice that received leukocytes from sham-operated control mice. After 24 h, recipient mice were anesthetized and samples were collected. Alanine aminotransferase, aspartate aminotransferase, and hepatic malondialdehyde increased significantly, and hepatic glutathione decreased significantly in intact recipient mice that received leukocytes from IR mice in comparison with intact recipient mice that received leukocytes from sham-operated control mice. Loss of normal liver architecture, cytoplasmic vacuolization, and focal infiltration of leukocytes were seen. These results suggest that leukocytes are one of the possible factors that contribute to liver damage after renal IR injury and this damage is partly due to the induction of oxidative stress.

  16. Proton-induced radiation damage in germanium detectors

    NASA Technical Reports Server (NTRS)

    Brueckner, J.; Koerfer, M.; Waenke, H.; Schroeder, A. N. F.; Filges, D.; Dragovitsch, P.; Englert, P. A. J.; Starr, R.; Trombka, J. I.

    1991-01-01

    High-purity germanium (HPGe) detectors will be used in future space missions for gamma-ray measurements and will be subject to interactions with energetic particles. To simulate this process, several large-volume n-type HPGe detectors were incrementally exposed to a particle fluence of up to 10 to the 8th protons/sq cm (proton energy: 1.5 GeV) at different operating temperatures (90 to 120 K) to induce radiation damage. Basic scientific and engineering data on detector performance were collected. During the incremental irradiation, the peak shape produced by the detectors showed a significant change from a Gaussian shape to a broad complex structure. After the irradiation, all detectors were thoroughly characterized by measuring many parameters. To remove the accumulated radiation damage, the detectors were stepwise-annealed at temperatures below 110 C, while kept in their specially designed cryostats. This study shows that n-type HPGe detectors can be used in charged-particle environments as high-energy resolution devices until a certain level of radiation damage is accumulated and that the damage can be removed at moderate annealing temperatures and the detector returned to operating condition.

  17. Proton-induced radiation damage in germanium detectors

    SciTech Connect

    Bruckner, J.; Korfer, M.; Wanke, H. , Mainz ); Schroeder, A.N.F. ); Figes, D.; Dragovitsch, P. ); Englert, P.A.J. ); Starr, R.; Trombka, J.I. . Goddard Space Flight Center); Taylor, I. ); Drake, D.M.; Shunk, E.R. )

    1991-04-01

    High-purity germanium (HPGe) detectors will be used in future space missions for gamma-ray measurements and will be subject to interactions with energetic particles. To simulate this process several large-volume n-type HPGe detectors were incrementally exposed to a particle fluence of up to 10{sub 8} protons cm{sup {minus}2} (proton energy: 1.5 GeV) at different operating temperatures (90 to 120 K) to induce radiation damage. Basic scientific as well as engineering data on detector performance were collected. During the incremental irradiation, the peak shape produced by the detectors showed a significant change from a Gaussian shape to a broad complex structure. After the irradiation all detectors were thoroughly characterized by measuring many parameters. To remove the accumulated radiation damage the detectors were stepwise annealed at temperatures T {le} 110{degrees}C while staying specially designed cryostats. This paper shows that n-type HPGe detectors can be used in charged particles environments as high-energy resolution devices until a certain level of radiation damage is accumulated and that the damage can be removed at moderate annealing temperatures and the detector returned to operating condition.

  18. Retinal damage induced by commercial light emitting diodes (LEDs).

    PubMed

    Jaadane, Imene; Boulenguez, Pierre; Chahory, Sabine; Carré, Samuel; Savoldelli, Michèle; Jonet, Laurent; Behar-Cohen, Francine; Martinsons, Christophe; Torriglia, Alicia

    2015-07-01

    Spectra of "white LEDs" are characterized by an intense emission in the blue region of the visible spectrum, absent in daylight spectra. This blue component and the high intensity of emission are the main sources of concern about the health risks of LEDs with respect to their toxicity to the eye and the retina. The aim of our study was to elucidate the role of blue light from LEDs in retinal damage. Commercially available white LEDs and four different blue LEDs (507, 473, 467, and 449nm) were used for exposure experiments on Wistar rats. Immunohistochemical stain, transmission electron microscopy, and Western blot were used to exam the retinas. We evaluated LED-induced retinal cell damage by studying oxidative stress, stress response pathways, and the identification of cell death pathways. LED light caused a state of suffering of the retina with oxidative damage and retinal injury. We observed a loss of photoreceptors and the activation of caspase-independent apoptosis, necroptosis, and necrosis. A wavelength dependence of the effects was observed. Phototoxicity of LEDs on the retina is characterized by a strong damage of photoreceptors and by the induction of necrosis. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Mitochondrial injury and dysfunction in hypertension-induced cardiac damage

    PubMed Central

    Eirin, Alfonso; Lerman, Amir; Lerman, Lilach O.

    2014-01-01

    Hypertension remains an important modifiable risk factor for cardiovascular disease, associated with increased morbidity and mortality. Deciphering the mechanisms involved in the pathogenesis of hypertension is critical, as its prevalence continues increasing worldwide. Mitochondria, the primary cellular energy producers, are numerous in parenchymal cells of the heart, kidney, and brain, major target organs in hypertension. These membrane-bound organelles not only maintain cellular respiration but also modulate several functions of the cell including proliferation, apoptosis, generation of reactive oxygen species, and intracellular calcium homeostasis. Therefore, mitochondrial damage and dysfunction compromise overall cell functioning. In recent years, significant advances increased our understanding of mitochondrial morphology, bioenergetics, and homeostasis, and in turn of their role in several diseases, so that mitochondrial abnormalities and dysfunction have been identified in experimental models of hypertension. In this review, we summarize current knowledge of the contribution of dysfunctional mitochondria to the pathophysiology of hypertension-induced cardiac damage, as well as available evidence of mitochondrial injury-induced damage in other organs. Finally, we discuss the capability of antihypertensive therapy to ameliorate hypertensive mitochondrial injury, and the potential position of mitochondria as therapeutic targets in patients with hypertension. PMID:25385092

  20. Exercise-Induced Muscle Damage and Running Economy in Humans

    PubMed Central

    Assumpção, Cláudio de Oliveira; Lima, Leonardo Coelho Rabello; Oliveira, Felipe Bruno Dias; Greco, Camila Coelho; Denadai, Benedito Sérgio

    2013-01-01

    Running economy (RE), defined as the energy demand for a given velocity of submaximal running, has been identified as a critical factor of overall distance running performance. Plyometric and resistance trainings, performed during a relatively short period of time (~15–30 days), have been successfully used to improve RE in trained athletes. However, these exercise types, particularly when they are unaccustomed activities for the individuals, may cause delayed onset muscle soreness, swelling, and reduced muscle strength. Some studies have demonstrated that exercise-induced muscle damage has a negative impact on endurance running performance. Specifically, the muscular damage induced by an acute bout of downhill running has been shown to reduce RE during subsequent moderate and high-intensity exercise (>65% VO2max). However, strength exercise (i.e., jumps, isoinertial and isokinetic eccentric exercises) seems to impair RE only for subsequent high-intensity exercise (~90% VO2max). Finally, a single session of resistance exercise or downhill running (i.e., repeated bout effect) attenuates changes in indirect markers of muscle damage and blunts changes in RE. PMID:23431253

  1. Viral Carcinogenesis: Factors Inducing DNA Damage and Virus Integration

    PubMed Central

    Chen, Yan; Williams, Vonetta; Filippova, Maria; Filippov, Valery; Duerksen-Hughes, Penelope

    2014-01-01

    Viruses are the causative agents of 10%–15% of human cancers worldwide. The most common outcome for virus-induced reprogramming is genomic instability, including accumulation of mutations, aberrations and DNA damage. Although each virus has its own specific mechanism for promoting carcinogenesis, the majority of DNA oncogenic viruses encode oncogenes that transform infected cells, frequently by targeting p53 and pRB. In addition, integration of viral DNA into the human genome can also play an important role in promoting tumor development for several viruses, including HBV and HPV. Because viral integration requires the breakage of both the viral and the host DNA, the integration rate is believed to be linked to the levels of DNA damage. DNA damage can be caused by both endogenous and exogenous factors, including inflammation induced by either the virus itself or by co-infections with other agents, environmental agents and other factors. Typically, cancer develops years to decades following the initial infection. A better understanding of virus-mediated carcinogenesis, the networking of pathways involved in transformation and the relevant risk factors, particularly in those cases where tumorigenesis proceeds by way of virus integration, will help to suggest prophylactic and therapeutic strategies to reduce the risk of virus-mediated cancer. PMID:25340830

  2. Radiation-induced thymine base damage in replicating chromatin

    SciTech Connect

    Warters, R.L.; Childers, T.J.

    1982-06-01

    The efficiency of radiation-induced production of 5',6'-dihydroxydihydrothymine (t/sup ..gamma../)-type damage was determined in nascent and mature chromatin DNA for the dose range of 50 to 150 krad. These large doses affected neither the total fraction of nuclear DNA in chromatin subunits nor the nucleosome subunit repeat length. The DNA in nascent chromatin, however, was found to be 3.3 times more sensitive than mature chromatin DNA to ..gamma..-ray (/sup 137/Cs)-induced t/sup ..gamma../-type damage, while thymine damage of this type was uniformly distributed in the nucleosomal DNA of mature chromatin (i.e., in the nucleosome core and spacer DNA). The half-time for the transition of nascent DNA sensitivity to mature chromatin DNA sensitivity levels was the same as the half-time at 37/sup 0/C for the maturation of nascent into mature chromatin structure. The rate at which nascent chromatin matured was unaffected by radiation doses as large as 150 krad. The most logical explanation for the greater sensitivity of nascent DNA to radiation is the decreased concentration of histone chromosomal proteins in nascent chromatin.

  3. NLRP3 Inflammasome Mediates Aldosterone-Induced Vascular Damage.

    PubMed

    Bruder-Nascimento, Thiago; Ferreira, Nathanne S; Zanotto, Camila Z; Ramalho, Fernanda; Pequeno, Isabela O; Olivon, Vania C; Neves, Karla B; Alves-Lopes, Rheure; Campos, Eduardo; Silva, Carlos Alberto A; Fazan, Rubens; Carlos, Daniela; Mestriner, Fabiola L; Prado, Douglas; Pereira, Felipe V; Braga, Tarcio; Luiz, Joao Paulo M; Cau, Stefany B; Elias, Paula C; Moreira, Ayrton C; Câmara, Niels O; Zamboni, Dario S; Alves-Filho, Jose Carlos; Tostes, Rita C

    2016-12-06

    Inflammation is a key feature of aldosterone-induced vascular damage and dysfunction, but molecular mechanisms by which aldosterone triggers inflammation remain unclear. The NLRP3 inflammasome is a pivotal immune sensor that recognizes endogenous danger signals triggering sterile inflammation. We analyzed vascular function and inflammatory profile of wild-type (WT), NLRP3 knockout (NLRP3(-/-)), caspase-1 knockout (Casp-1(-/-)), and interleukin-1 receptor knockout (IL-1R(-/-)) mice treated with vehicle or aldosterone (600 µg·kg(-1)·d(-1) for 14 days through osmotic mini-pump) while receiving 1% saline to drink. Here, we show that NLRP3 inflammasome plays a central role in aldosterone-induced vascular dysfunction. Long-term infusion of aldosterone in mice resulted in elevation of plasma interleukin-1β levels and vascular abnormalities. Mice lacking the IL-1R or the inflammasome components NLRP3 and caspase-1 were protected from aldosterone-induced vascular damage. In vitro, aldosterone stimulated NLRP3-dependent interleukin-1β secretion by bone marrow-derived macrophages by activating nuclear factor-κB signaling and reactive oxygen species generation. Moreover, chimeric mice reconstituted with NLRP3-deficient hematopoietic cells showed that NLRP3 in immune cells mediates aldosterone-induced vascular damage. In addition, aldosterone increased the expression of NLRP3, active caspase-1, and mature interleukin-1β in human peripheral blood mononuclear cells. Hypertensive patients with hyperaldosteronism or normal levels of aldosterone exhibited increased activity of NLRP3 inflammasome, suggesting that the effect of hyperaldosteronism on the inflammasome may be mediated through high blood pressure. Together, these data demonstrate that NLRP3 inflammasome, through activation of IL-1R, is critically involved in the deleterious vascular effects of aldosterone, placing NLRP3 as a potential target for therapeutic interventions in conditions with high aldosterone levels

  4. Comparison of fresh and cultured islets from human and porcine pancreata.

    PubMed

    Noguchi, H; Naziruddin, B; Shimoda, M; Fujita, Y; Chujo, D; Takita, M; Peng, H; Sugimoto, K; Itoh, T; Tamura, Y; Olsen, G S; Kobayashi, N; Onaca, N; Levy, M F; Matsumoto, S

    2010-01-01

    For clinical islet transplantation, many centers have recently introduced of human islet cultures prior to transplantation. They provide flexibility to evaluate isolated islets and pretreat patients. However, isolated islets deteriorate rapidly in culture. In the present study, we compared fresh human and porcine islets with cultured islets for c-Jun NH(2)-terminal kinase (JNK) activity. Islet isolations from human and porcine pancreata were performed using the standard Ricordi technique with a modified Edmonton protocol. Isolated islets cultured for 24 hours at 37 degrees C with 5% CO(2) in culture medium were evaluated for counts and JNK activity. After 24 hours of culture, the percentages of surviving islets were 86.9% for human and 47.3% for porcine sources. JNK activity in isolated islets declined to a low baseline level after 24-hour culture. Both human and porcine islets deteriorated rapidly in 24-hour cultures, although the in vitro conditions did not induce JNK activation. Copyright 2010 Elsevier Inc. All rights reserved.

  5. Human BM stem cells initiate angiogenesis in human islets in vitro.

    PubMed

    Luo, J Z Q; Xiong, F; Al-Homsi, A S; Roy, T; Luo, L G

    2011-08-01

    BM stem cells may have regenerative effects on islet function through angiogenesis. Human islets (100islet equivalent/mL) were cultured alone (control) or co-cultured (experimental group) with whole human BM (1 × 10(6) cells/mL) for 210 days. A protein array measuring angiogenesis factors found upregulated (experimental vs control, day 210) proteins levels of VEGF-a (535 vs 2 pg/mL), PDGF (280.79 vs 0 pg/mL), KGF (939 vs 8 pg/mL), TIMP-1 (4592 vs 4332 pg/mL) and angiogenin (506 vs 97 pg/mL). Lower protein levels of angiopoietin-2 (5 vs 709 pg/mL) were observed. Depletion of pro-angiogenesis factors in co-culture decreased the effects of BM-induced islet vascularization. Depletion of VEGF-a, eKGF and PDGF significantly reduced islet vascularization but individual depletion of KGF and PDGF had less effects overall on vessel formation. BM-induced vascularization showed significant endothelial cell distribution. Islet vascularization was linked to islet growth. A decrease in islet size indicated poor vascularization. Insulin release was evident in the tissues generated from human islet-BM co-culture throughout the entire culture period. Significant increase in insulin (28.66-fold vs control) and glucagon (24.4-fold vs control) gene expression suggest BM can induce endocrine cell regeneration. In conclusion, BM promotes human islet tissue regeneration via regulation of angiogenesis factors.

  6. Revision of laser-induced damage threshold evaluation from damage probability data

    SciTech Connect

    Bataviciute, Gintare; Grigas, Povilas; Smalakys, Linas; Melninkaitis, Andrius

    2013-04-15

    In this study, the applicability of commonly used Damage Frequency Method (DFM) is addressed in the context of Laser-Induced Damage Threshold (LIDT) testing with pulsed lasers. A simplified computer model representing the statistical interaction between laser irradiation and randomly distributed damage precursors is applied for Monte Carlo experiments. The reproducibility of LIDT predicted from DFM is examined under both idealized and realistic laser irradiation conditions by performing numerical 1-on-1 tests. A widely accepted linear fitting resulted in systematic errors when estimating LIDT and its error bars. For the same purpose, a Bayesian approach was proposed. A novel concept of parametric regression based on varying kernel and maximum likelihood fitting technique is introduced and studied. Such approach exhibited clear advantages over conventional linear fitting and led to more reproducible LIDT evaluation. Furthermore, LIDT error bars are obtained as a natural outcome of parametric fitting which exhibit realistic values. The proposed technique has been validated on two conventionally polished fused silica samples (355 nm, 5.7 ns).

  7. Revision of laser-induced damage threshold evaluation from damage probability data

    NASA Astrophysics Data System (ADS)

    BatavičiutÄ--, GintarÄ--; Grigas, Povilas; Smalakys, Linas; Melninkaitis, Andrius

    2013-04-01

    In this study, the applicability of commonly used Damage Frequency Method (DFM) is addressed in the context of Laser-Induced Damage Threshold (LIDT) testing with pulsed lasers. A simplified computer model representing the statistical interaction between laser irradiation and randomly distributed damage precursors is applied for Monte Carlo experiments. The reproducibility of LIDT predicted from DFM is examined under both idealized and realistic laser irradiation conditions by performing numerical 1-on-1 tests. A widely accepted linear fitting resulted in systematic errors when estimating LIDT and its error bars. For the same purpose, a Bayesian approach was proposed. A novel concept of parametric regression based on varying kernel and maximum likelihood fitting technique is introduced and studied. Such approach exhibited clear advantages over conventional linear fitting and led to more reproducible LIDT evaluation. Furthermore, LIDT error bars are obtained as a natural outcome of parametric fitting which exhibit realistic values. The proposed technique has been validated on two conventionally polished fused silica samples (355 nm, 5.7 ns).

  8. Chlorambucil induced chromosome damage in juvenile chronic arthritis.

    PubMed Central

    Palmer, R G; Varonos, S; Doré, C J; Denman, A M; Ansell, B M

    1985-01-01

    Sister chromatid exchanges, a sensitive measure of chromosome damage, were counted in peripheral blood lymphocytes from 23 patients with juvenile chronic arthritis receiving long term, low dose chlorambucil treatment. Thirty five patients with juvenile chronic arthritis who had not been treated with cytotoxic drugs served as controls. All of the treated patients have cells with abnormal sister chromatid exchange frequencies. Damage is related to the daily dose and may, in part, be determined by the duration of treatment. Sister chromatid exchanges from nine patients who had received chlorambucil at some time in the past remained high for at least five months after stopping the drug. Long term follow up will determine whether sister chromatid exchange analysis can help predict those most at risk of drug induced malignancies. Images Fig. 1 PMID:4073932

  9. Laser pointer induced macular damage: case report and mini review.

    PubMed

    Turaka, Kiran; Bryan, J Shepard; Gordon, Alan J; Reddy, Rahul; Kwong, Henry M; Sell, Clive H

    2012-06-01

    To report laser pointer induced damage to retina and choroid and briefly review literature. A case report of a 13-year old Caucasian boy developed blurry central vision and central scotoma in right eye (OD). He was exposed for one minute to class IIIA green laser pointer of 650 nm wavelength and 5 mW power. Clinical examination showed a grayish lesion in foveal region. Ancillary testing revealed disruption of the retinal pigment epithelial (RPE) layer in foveal region and indocyanine green angiography demonstrated evidence of choroidal hypofluorescence suggestive of choroidal infarction in OD. Visual acuity improved from 20/100 to 20/60 in one day and he was treated with tapering doses of oral prednisolone (40 mg) for 3 weeks. Laser pointer with a power of >5 mW caused damage to RPE in the macula. Children should not be given laser pointers as toys especially those with label of danger instructions.

  10. Damage induced by paracetamol compared with N-acetylcysteine.

    PubMed

    Kisaoglu, Abdullah; Ozogul, Bunyami; Turan, Mehmet Ibrahim; Yilmaz, Ismayil; Demiryilmaz, Ismail; Atamanalp, Sabri Selcuk; Bakan, Ebubekir; Suleyman, Halis

    2014-09-01

    This study investigated the effect of thiamine pyrophosphate (TPP) on oxidative liver damage induced in rats with high-dose paracetamol. Rats for this experiment were divided into the following groups: healthy control, paracetamol control, thiamine + paracetamol, TPP + paracetamol, and N-acetylcysteine + paracetamol. Oxidant and antioxidant parameters and liver function test levels were compared between the groups. The results show that TPP and N-acetylcysteine with paracetamol equally prevented a rise in oxidants such as malondialdehyde and nitric oxide. They also prevented a decrease in enzymatic and nonenzymatic antioxidants such as glutathione, glutathione peroxidase, glutaredoxin, glutathione S-transferase, superoxide dismutase, and catalase in the rat liver. Thiamine pyrophosphate and N-acetylcysteine had a similar positive effect on oxidative damage caused by paracetamol hepatotoxicity. These findings show that TPP may be beneficial in paracetamol hepatotoxicity. Copyright © 2014. Published by Elsevier B.V.

  11. Dietary strategies to recover from exercise-induced muscle damage.

    PubMed

    Sousa, Mónica; Teixeira, Vítor H; Soares, José

    2014-03-01

    Exhaustive or unaccustomed intense exercise can cause exercise-induced muscle damage (EIMD) and its undesirable consequences may decrease the ability to exercise and to adhere to a training programme. This review briefly summarises the muscle damage process, focusing predominantly on oxidative stress and inflammation as contributing factors, and describes how nutrition may be positively used to recover from EIMD. The combined intake of carbohydrates and proteins and the use of antioxidants and/or anti-inflammatory nutrients within physiological ranges are interventions that may assist the recovery process. Although the works studying food instead of nutritional supplements are very scarce, their results seem to indicate that food might be a favourable option as a recovery strategy. To date, the only tested foods were milk, cherries, blueberries and pomegranate with promising results. Other potential solutions are foods rich in protein, carbohydrates, antioxidants and/or anti-inflammatory nutrients.

  12. Detection of enteroviruses in stools precedes islet autoimmunity by several months: possible evidence for slowly operating mechanisms in virus-induced autoimmunity.

    PubMed

    Honkanen, Hanna; Oikarinen, Sami; Nurminen, Noora; Laitinen, Olli H; Huhtala, Heini; Lehtonen, Jussi; Ruokoranta, Tanja; Hankaniemi, Minna M; Lecouturier, Valérie; Almond, Jeffrey W; Tauriainen, Sisko; Simell, Olli; Ilonen, Jorma; Veijola, Riitta; Viskari, Hanna; Knip, Mikael; Hyöty, Heikki

    2017-03-01

    This case-control study was nested in a prospective birth cohort to evaluate whether the presence of enteroviruses in stools was associated with the appearance of islet autoimmunity in the Type 1 Diabetes Prediction and Prevention study in Finland. Altogether, 1673 longitudinal stool samples from 129 case children who turned positive for multiple islet autoantibodies and 3108 stool samples from 282 matched control children were screened for the presence of enterovirus RNA using RT-PCR. Viral genotype was detected by sequencing. Case children had more enterovirus infections than control children (0.8 vs 0.6 infections per child). Time-dependent analysis indicated that this excess of infections occurred more than 1 year before the first detection of islet autoantibodies (6.3 vs 2.1 infections per 10 follow-up years). No such difference was seen in infections occurring less than 1 year before islet autoantibody seroconversion or after seroconversion. The most frequent enterovirus types included coxsackievirus A4 (28% of genotyped viruses), coxsackievirus A2 (14%) and coxsackievirus A16 (11%). The results suggest that enterovirus infections diagnosed by detecting viral RNA in stools are associated with the development of islet autoimmunity with a time lag of several months.

  13. Characterizing the Mechanistic Pathways of the Instant Blood-Mediated Inflammatory Reaction in Xenogeneic Neonatal Islet Cell Transplantation

    PubMed Central

    Liuwantara, David; Chew, Yi Vee; Favaloro, Emmanuel J.; Hawkes, Joanne M.; Burns, Heather L.; O'Connell, Philip J.; Hawthorne, Wayne J.

    2016-01-01

    Introduction The instant blood-mediated inflammatory reaction (IBMIR) causes major loss of islets after transplantation and consequently represents the initial barrier to survival of porcine neonatal islet cell clusters (NICC) after xenotransplantation. Methods This study used novel assays designed to characterize the various immunologic components responsible for xenogeneic IBMIR to identify initiators and investigate processes of IBMIR-associated coagulation, complement activation and neutrophil infiltration. The IBMIR was induced in vitro by exposing NICC to platelet-poor or platelet-rich human plasma or isolated neutrophils. Results We found that xenogeneic IBMIR was characterized by rapid, platelet-independent thrombin generation, with addition of platelets both accelerating and exacerbating this response. Platelet-independent complement activation was observed as early as 30 minutes after NICC exposure to plasma. However, membrane attack complex formation was not observed in NICC histopathology sections until after 60 minutes. We demonstrated for the first time that NICC-mediated complement activation was necessary for neutrophil activation in the xenogeneic IBMIR setting. Finally, using the Seahorse extracellular flux analyzer, we identified substantial loss of islet function (up to 40%) after IBMIR with surviving NICC showing evidence of mitochondrial damage. Conclusions This study used novel assays to describe multiple key pathways by which xenogeneic IBMIR causes islet destruction, allowing further refinement of future interventions aimed at resolving the issue of IBMIR in xenotransplantation. PMID:27500267

  14. Opportunities for nutritional amelioration of radiation-induced cellular damage

    NASA Technical Reports Server (NTRS)

    Turner, Nancy D.; Braby, Leslie A.; Ford, John; Lupton, Joanne R.

    2002-01-01

    The closed environment and limited evasive capabilities inherent in space flight cause astronauts to be exposed to many potential harmful agents (chemical contaminants in the environment and cosmic radiation exposure). Current power systems used to achieve space flight are prohibitively expensive for supporting the weight requirements to fully shield astronauts from cosmic radiation. Therefore, radiation poses a major, currently unresolvable risk for astronauts, especially for long-duration space flights. The major detrimental radiation effects that are of primary concern for long-duration space flights are damage to the lens of the eye, damage to the immune system, damage to the central nervous system, and cancer. In addition to the direct damage to biological molecules in cells, radiation exposure induces oxidative damage. Many natural antioxidants, whether consumed before or after radiation exposure, are able to confer some level of radioprotection. In addition to achieving beneficial effects from long-known antioxidants such as vitamins E and C and folic acid, some protection is conferred by several recently discovered antioxidant molecules, such as flavonoids, epigallocatechin, and other polyphenols. Somewhat counterintuitive is the protection provided by diets containing elevated levels of omega-3 polyunsaturated fatty acids, considering they are thought to be prone to peroxidation. Even with the information we have at our disposal, it will be difficult to predict the types of dietary modifications that can best reduce the risk of radiation exposure to astronauts, those living on Earth, or those enduring diagnostic or therapeutic radiation exposure. Much more work must be done in humans, whether on Earth or, preferably, in space, before we are able to make concrete recommendations.

  15. Opportunities for nutritional amelioration of radiation-induced cellular damage

    NASA Technical Reports Server (NTRS)

    Turner, Nancy D.; Braby, Leslie A.; Ford, John; Lupton, Joanne R.

    2002-01-01

    The closed environment and limited evasive capabilities inherent in space flight cause astronauts to be exposed to many potential harmful agents (chemical contaminants in the environment and cosmic radiation exposure). Current power systems used to achieve space flight are prohibitively expensive for supporting the weight requirements to fully shield astronauts from cosmic radiation. Therefore, radiation poses a major, currently unresolvable risk for astronauts, especially for long-duration space flights. The major detrimental radiation effects that are of primary concern for long-duration space flights are damage to the lens of the eye, damage to the immune system, damage to the central nervous system, and cancer. In addition to the direct damage to biological molecules in cells, radiation exposure induces oxidative damage. Many natural antioxidants, whether consumed before or after radiation exposure, are able to confer some level of radioprotection. In addition to achieving beneficial effects from long-known antioxidants such as vitamins E and C and folic acid, some protection is conferred by several recently discovered antioxidant molecules, such as flavonoids, epigallocatechin, and other polyphenols. Somewhat counterintuitive is the protection provided by diets containing elevated levels of omega-3 polyunsaturated fatty acids, considering they are thought to be prone to peroxidation. Even with the information we have at our disposal, it will be difficult to predict the types of dietary modifications that can best reduce the risk of radiation exposure to astronauts, those living on Earth, or those enduring diagnostic or therapeutic radiation exposure. Much more work must be done in humans, whether on Earth or, preferably, in space, before we are able to make concrete recommendations.

  16. Opportunities for nutritional amelioration of radiation-induced cellular damage.

    PubMed

    Turner, Nancy D; Braby, Leslie A; Ford, John; Lupton, Joanne R

    2002-10-01

    The closed environment and limited evasive capabilities inherent in space flight cause astronauts to be exposed to many potential harmful agents (chemical contaminants in the environment and cosmic radiation exposure). Current power systems used to achieve space flight are prohibitively expensive for supporting the weight requirements to fully shield astronauts from cosmic radiation. Therefore, radiation poses a major, currently unresolvable risk for astronauts, especially for long-duration space flights. The major detrimental radiation effects that are of primary concern for long-duration space flights are damage to the lens of the eye, damage to the immune system, damage to the central nervous system, and cancer. In addition to the direct damage to biological molecules in cells, radiation exposure induces oxidative damage. Many natural antioxidants, whether consumed before or after radiation exposure, are able to confer some level of radioprotection. In addition to achieving beneficial effects from long-known antioxidants such as vitamins E and C and folic acid, some protection is conferred by several recently discovered antioxidant molecules, such as flavonoids, epigallocatechin, and other polyphenols. Somewhat counterintuitive is the protection provided by diets containing elevated levels of omega-3 polyunsaturated fatty acids, considering they are thought to be prone to peroxidation. Even with the information we have at our disposal, it will be difficult to predict the types of dietary modifications that can best reduce the risk of radiation exposure to astronauts, those living on Earth, or those enduring diagnostic or therapeutic radiation exposure. Much more work must be done in humans, whether on Earth or, preferably, in space, before we are able to make concrete recommendations.

  17. Protective effects of honokiol against methylglyoxal-induced osteoblast damage.

    PubMed

    Suh, Kwang Sik; Chon, Suk; Choi, Eun Mi

    2016-01-25

    Honokiol is an active compound isolated from Magnolia officinalis that has been used without notable side effects in traditional medicine. We investigated the effects of honokiol against methylglyoxal (MG)-induced cytotoxicity in MC3T3-E1 osteoblast cells and the possible molecular mechanism(s) involved. The results showed that honokiol alleviated MG-induced cell death and the production of intracellular ROS, mitochondrial superoxide, cardiolipin peroxidation, and inflammatory cytokines. MG induction of the soluble receptor for advanced glycation end product (AGE) was reduced by pretreatment with honokiol. Furthermore, honokiol increased the levels of Nrf2 and increased the levels of glutathione and the activity of glyoxalase I. Pretreatment with honokiol prior to MG exposure reduced MG-induced mitochondrial dysfunction and alleviated MG-induced reduction of nitric oxide and PGC1α levels, suggesting that honokiol may induce mitochondrial biogenesis. It was concluded that honokiol could be useful in the attenuation of MG-induced cell damage. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. Role of neutrophils in acrylonitrile-induced gastric mucosal damage.

    PubMed

    Hamdy, Nadia M; Al-Abbasi, Fahad A; Alghamdi, Hassan A; Tolba, Mai F; Esmat, Ahmed; Abdel-Naim, Ashraf B

    2012-01-25

    Acrylonitrile (ACN) is a widely used intermediate in the manufacture of plastics, acrylic fibers, synthetic rubbers and resins that are used in a variety of products including food containers and medical devices. ACN is a possible human carcinogen and a documented animal carcinogen, with the stomach being an important target of its toxicity. ACN has been previously reported to require metabolic activation to reactive intermediates and finally to cyanide (CN⁻). The current study aimed at exploring the potential role of neutrophils in ACN-induced gastric damage in rats. Experimental neutropenia was attained by injecting rats with methotrexate. This significantly ameliorated gastric mucosal injury induced by ACN. This is evidenced by protection against the increase in gastric ulcer index, myeloperoxidase (MPO) activity and CN⁻ level. Also, neutropenia guarded against the decrease in prostaglandin E2 (PGE2), induction of oxidative stress and reduction of total nitrites and alleviated histopathological alterations in rat stomachs. These data indicate that neutrophil infiltration is, at least partly, involved in ACN-induced gastric damage in rats.

  19. Photoacoustic imaging of angiogenesis in subdermal islet transplant sites

    NASA Astrophysics Data System (ADS)

    Shi, Wei; Pawlick, Rena; Bruni, Antonio; Rafiei, Yasmin; Pepper, Andrew R.; Gala-Lopez, Boris; Choi, Min; Malcolm, Andrew; Zemp, Roger J.; Shapiro, A. M. James

    2016-03-01

    Exogenous insulin administration is the mainstay treatment therapy for patients with Type-1 diabetes mellitus (T1DM). However, for select patients, clinical islet transplantation is an alternative therapeutic treatment. In this procedure, islets are transplanted into the hepatic portal vein, and despite improved success within the last decade, obstacles are still associated with this approach. It has been discovered that the subcutaneous space may be an effective alternative site for islet transplantation, and may provide advantages of easy access and potential for simple monitoring. The ability to monitor islet viability and the transplant microenvironment may be key to future success in islet transplantation. A subcutaneous device-less technique has been developed to facilitate angiogenesis in the islet transplant site, however, a method for monitoring the potential engraftment site have yet to be explored fully. Here we demonstrate the ability to track angiogenesis in mice with 1, 2, 3 and 4 weeks post-catheter implant on both sides of the abdomen using a FujiFilm VisualSonics Vevo-LAZR system. Quantitative analysis on vessel densities exhibited gradual vessel growth successfully induced by catheter implantation. Our study demonstrates the ability of employing photoacoustic and micro-ultrasound imaging to track angiogenesis around the catheter site prior to islet transplantation.

  20. Identification of T cell subsets and class I and class II antigen expression in islet grafts and pancreatic islets of diabetic BioBreeding/Worcester rats.

    PubMed Central

    Weringer, E. J.; Like, A. A.

    1988-01-01

    The BioBreeding/Worcester (BB/Wor) rat develops a spontaneous disorder that closely resembles human insulin-dependent (Type I) diabetes mellitus. The syndrome is preceded by lymphocytic insulitis that destroys pancreatic beta cells. The morphologic features of the spontaneous insulitis lesions are also observed within islets transplanted beneath the renal capsule of diabetes-prone and diabetic animals. This study reports the results of experiments in which immunohistochemical techniques were used to characterize the phenotype of the infiltrating mononuclear cells and detect the expression of class I and class II MHC antigens in native islets and islet transplants in diabetic and diabetes-prone BB/Wor rats. The infiltrates within native pancreatic islets and islet grafts were comprised predominantly of Ia+ cells (dendritic cells and macrophages) CD4+ cells (helper/inducer lymphocytes and macrophages), CD5+ (pan-T) cells and smaller numbers of CD8+ (cytotoxic/suppressor and NK) cells. Pancreatic and graft insulitis were accompanied by markedly enhanced class I antigen expression on islet and exocrine cells. Class II (Ia) antigens were not detected on normal islet cells, islets undergoing insulitis or on islet transplants subjected to immune attack. In islet grafts stained with polymorphic MAbs that distinguish Ia antigens of donor and host origin, Ia antigen expression was limited to infiltrating dendritic cells and macrophages of host origin. It is concluded that the phenotypes of infiltrating mononuclear cells that comprise the insulitis lesion in spontaneous BB/Wor diabetes, and the inflammatory attack on islets transplanted into diabetic BB/Wor rats are the same, that pancreatic islet and graft insulitis occur in the presence of enhanced class I antigen expression but in the absence of class II antigen expression, and that infiltrating Ia+ cells within islet grafts are exclusively of recipient (BB/Wor) origin and may explain the initiation of immune insulitis

  1. Oxidative damage and neurodegeneration in manganese-induced neurotoxicity

    SciTech Connect

    Milatovic, Dejan; Yu, Yingchun

    2009-10-15

    Exposure to excessive manganese (Mn) levels results in neurotoxicity to the extrapyramidal system and the development of Parkinson's disease (PD)-like movement disorder, referred to as manganism. Although the mechanisms by which Mn induces neuronal damage are not well defined, its neurotoxicity appears to be regulated by a number of factors, including oxidative injury, mitochondrial dysfunction and neuroinflammation. To investigate the mechanisms underlying Mn neurotoxicity, we studied the effects of Mn on reactive oxygen species (ROS) formation, changes in high-energy phosphates (HEP), neuroinflammation mediators and associated neuronal dysfunctions both in vitro and in vivo. Primary cortical neuronal cultures showed concentration-dependent alterations in biomarkers of oxidative damage, F{sub 2}-isoprostanes (F{sub 2}-IsoPs) and mitochondrial dysfunction (ATP), as early as 2 h following Mn exposure. Treatment of neurons with 500 {mu}M Mn also resulted in time-dependent increases in the levels of the inflammatory biomarker, prostaglandin E{sub 2} (PGE{sub 2}). In vivo analyses corroborated these findings, establishing that either a single or three (100 mg/kg, s.c.) Mn injections (days 1, 4 and 7) induced significant increases in F{sub 2}-IsoPs and PGE{sub 2} in adult mouse brain 24 h following the last injection. Quantitative morphometric analyses of Golgi-impregnated striatal sections from mice exposed to single or three Mn injections revealed progressive spine degeneration and dendritic damage of medium spiny neurons (MSNs). These findings suggest that oxidative stress, mitochondrial dysfunction and neuroinflammation are underlying mechanisms in Mn-induced neurodegeneration.

  2. Silica radical-induced DNA damage and lipid peroxidation.

    PubMed Central

    Shi, X; Mao, Y; Daniel, L N; Saffiotti, U; Dalal, N S; Vallyathan, V

    1994-01-01

    In recent years, more attention has been given to the mechanism of disease induction caused by the surface properties of minerals. In this respect, specific research needs to be focused on the biologic interactions of oxygen radicals generated by mineral particles resulting in cell injury and DNA damage leading to fibrogenesis and carcinogenesis. In this investigation, we used electron spin resonance (ESR) and spin trapping to study oxygen radical generation from aqueous suspensions of freshly fractured crystalline silica. Hydroxyl radical (.OH), superoxide radical (O2.-) and singlet oxygen (1O2) were all detected. Superoxide dismutase (SOD) partially inhibited .OH yield, whereas catalase abolished .OH generation. H2O2 enhanced .OH generation while deferoxamine inhibited it, indicating that .OH is generated via a Haber-Weiss type reaction. These spin trapping measurements provide the first evidence that aqueous suspensions of silica particles generate O2.- and 1O2. Oxygen consumption measurements indicate that freshly fractured silica uses molecular oxygen to generate O2.- and 1O2. Electrophoretic assays of in vitro DNA strand breakages showed that freshly fractured silica induced DNA strand breakage, which was inhibited by catalase and enhanced by H2O2. In an argon atmosphere, DNA damage was suppressed, showing that molecular oxygen is required for the silica-induced DNA damage. Incubation of freshly fractured silica with linoleic acid generated linoleic acid-derived free radicals and caused dose-dependent lipid peroxidation as measured by ESR spin trapping and malondialdehyde formation. SOD, catalase, and sodium benzoate inhibited lipid peroxidation by 49, 52, and 75%, respectively, again showing the role of oxygen radicals in silica-induced lipid peroxidation.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 7. PMID:7705289

  3. Torin2 Suppresses Ionizing Radiation-Induced DNA Damage Repair.

    PubMed

    Udayakumar, Durga; Pandita, Raj K; Horikoshi, Nobuo; Liu, Yan; Liu, Qingsong; Wong, Kwok-Kin; Hunt, Clayton R; Gray, Nathanael S; Minna, John D; Pandita, Tej K; Westover, Kenneth D

    2016-05-01

    Several classes of inhibitors of the mammalian target of rapamycin (mTOR) have been developed based on its central role in sensing growth factor and nutrient levels to regulate cellular metabolism. However, its ATP-binding site closely resembles other phosphatidylinositol 3-kinase-related kinase (PIKK) family members, resulting in reactivity with these targets that may also be therapeutically useful. The ATP-competitive mTOR inhibitor, Torin2, shows biochemical activity against the DNA repair-associated proteins ATM, ATR and DNA-PK, which raises the possibility that Torin2 and related compounds might radiosensitize cancerous tumors. In this study Torin2 was also found to enhance ionizing radiation-induced cell killing in conditions where ATM was dispensable, confirming the requirement for multiple PIKK targets. Moreover, Torin2 did not influence the initial appearance of γ-H2AX foci after irradiation but significantly delayed the disappearance of radiation-induced γ-H2AX foci, indicating a DNA repair defect. Torin2 increased the number of radiation-induced S-phase specific chromosome aberrations and reduced the frequency of radiation-induced CtIP and Rad51 foci formation, suggesting that Torin2 works by blocking homologous recombination (HR)-mediated DNA repair resulting in an S-phase specific DNA repair defect. Accordingly, Torin2 reduced HR-mediated repair of I-Sce1-induced DNA damage and contributed to replication fork stalling. We conclude that radiosensitization of tumor cells by Torin2 is associated with disrupting ATR- and ATM-dependent DNA damage responses. Our findings support the concept of developing combination cancer therapies that incorporate ionizing radiation therapy and Torin2 or compounds with similar properties.

  4. Gender differences in alcohol-induced neurotoxicity and brain damage.

    PubMed

    Alfonso-Loeches, Silvia; Pascual, María; Guerri, Consuelo

    2013-09-06

    Considerable evidence has demonstrated that women are more vulnerable than men to the toxic effects of alcohol, although the results as to whether gender differences exist in ethanol-induced brain damage are contradictory. We have reported that ethanol, by activating the neuroimmune system and Toll-like receptors 4 (TLR4), can cause neuroinflammation and brain injury. However, whether there are gender differences in alcohol-induced neuroinflammation and brain injury are currently controversial. Using the brains of TLR4(+/+) and TLR4(-/-) (TLR4-KO) mice, we report that chronic ethanol treatment induces inflammatory mediators (iNOS and COX-2), cytokines (IL-1β, TNF-α), gliosis processes, caspase-3 activation and neuronal loss in the cerebral cortex of both female and male mice. Conversely, the levels of these parameters tend to be higher in female than in male mice. Using an in vivo imaging technique, our results further evidence that ethanol treatment triggers higher GFAP levels and lower MAP-2 levels in female than in male mice, suggesting a greater effect of ethanol-induced astrogliosis and less MAP-2(+) neurons in female than in male mice. Our results further confirm the pivotal role of TLR4 in alcohol-induced neuroinflammation and brain damage since the elimination of TLR4 protects the brain of males and females against the deleterious effects of ethanol. In short, the present findings demonstrate that, during the same period of ethanol treatment, females are more vulnerable than males to the neurotoxic/neuroinflammatory effects of ethanol, thus supporting the view that women are more susceptible than men to the medical consequences of alcohol abuse.

  5. Heavy metals, islet function and diabetes development.

    PubMed

    Chen, Ya Wen; Yang, Ching Yao; Huang, Chun Fa; Hung, Dong Zong; Leung, Yuk Man; Liu, Shing Hwa

    2009-01-01

    It has long been believed that heavy metals possess many adverse health effects. Uncontrolled industrialization has released heavy metal pollution in the world. Heavy metal pollutants damage organ functions and disrupt physiological homeostasis. Diabetes mellitus is growing in prevalence worldwide. Several studies have indicated that the deficiency and efficiency of some essential trace metals may play a role in the islet function and development of diabetes mellitus. Some toxic metals have also been shown to be elevated in biological samples of diabetes mellitus patients. In the present work, we review the important roles of heavy metals in islet function and diabetes development in which the in vitro, in vivo or human evidences are associated with exposure to zinc, arsenic, cadmium, mercury and nickel. Through this work, we summarize the evidence which suggests that some heavy metals may play an important role in diabetes mellitus as environmental risk factors.

  6. NMR spectroscopy in beta cell engineering and islet transplantation.

    PubMed

    Papas, K K; Colton, C K; Gounarides, J S; Roos, E S; Jarema, M A; Shapiro, M J; Cheng, L L; Cline, G W; Shulman, G I; Wu, H; Bonner-Weir, S; Weir, G C

    2001-11-01

    Islet transplantation is a promising method for restoring normoglycemia and alleviating the long term complications of diabetes. Widespread application of islet transplantation is hindered by the limited supply of human islets and requires a large increase in the availability of suitable insulin secreting tissue as well as robust quality assessment methodologies that can ensure safety and in vivo efficacy. We explore the application of nuclear magnetic resonance (NMR) spectroscopy in two areas relevant to beta cell engineering and islet transplantation: (1) the effect of genetic alterations on glucose metabolism, and (2) quality assessment of islet preparations prior to transplantation. Results obtained utilizing a variety of NMR techniques demonstrate the following: (1) Transfection of Rat1 cells with the c-myc oncogene (which may be involved in cell proliferation and cell cycle regulation) and overexpression of Bcl-2 (which may protect cells from stresses such as hypoxia and exposure to cytokines) introduce a wide array of alterations in cellular biochemistry, including changes in anaerobic and oxidative glucose metabolism, as assessed by 13C and 31P NMR spectroscopy. (2) Overnight incubation of islets and beta cells in the bottom of centrifuge tubes filled with medium at room temperature, as is sometimes done in islet transportation, exposes them to severe oxygen limitations that may cause cell damage. Such exposure, leading to reversible or irreversible damage, can be observed with NMR-detectable markers using conventional 13C and 31P NMR spectroscopy of extracts. In addition, markers of irreversible damage (as well as markers of hypoxia) can be detected and quantified without cell extraction using high-resolution magic angle spinning 1H NMR spectroscopy. Finally, acute ischemia in a bed of perfused beta cells leads to completely reversible changes that can be followed in real time with 31P NMR spectroscopy.

  7. Bee Products Prevent Agrichemical-Induced Oxidative Damage in Fish

    PubMed Central

    Ferreira, Daiane; Rocha, Helio Carlos; Kreutz, Luiz Carlos; Loro, Vania Lucia; Marqueze, Alessandra; Koakoski, Gessi; Santos da Rosa, João Gabriel; Gusso, Darlan; Oliveira, Thiago Acosta; de Abreu, Murilo Sander; Barcellos, Leonardo José Gil

    2013-01-01

    In southern South America and other parts of the world, aquaculture is an activity that complements agriculture. Small amounts of agrichemicals can reach aquaculture ponds, which results in numerous problems caused by oxidative stress in non-target organisms. Substances that can prevent or reverse agrichemical-induced oxidative damage may be used to combat these effects. This study includes four experiments. In each experiment, 96 mixed-sex, 6-month-old Rhamdia quelen (118±15 g) were distributed into eight experimental groups: a control group that was not exposed to contaminated water, three groups that were exposed to various concentrations of bee products, three groups that were exposed to various concentrations of bee products plus tebuconazole (TEB; Folicur 200 CE™) and a group that was exposed to 0.88 mg L−1 of TEB alone (corresponding to 16.6% of the 96-h LC50). We show that waterborne bee products, including royal jelly (RJ), honey (H), bee pollen (BP) and propolis (P), reversed the oxidative damage caused by exposure to TEB. These effects were likely caused by the high polyphenol contents of these bee-derived compounds. The most likely mechanism of action for the protective effects of bee products against tissue oxidation and the resultant damage is that the enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) are increased. PMID:24098336

  8. Bile-Induced DNA Damage in Salmonella enterica

    PubMed Central

    Prieto, Ana I.; Ramos-Morales, Francisco; Casadesús, Josep

    2004-01-01

    In the absence of DNA adenine methylase, growth of Salmonella enterica serovar Typhimurium is inhibited by bile. Mutations in any of the mutH, mutL, and mutS genes suppress bile sensitivity in a Dam− background, indicating that an active MutHLS system renders Dam− mutants bile sensitive. However, inactivation of the MutHLS system does not cause bile sensitivity. An analogy with Escherichia coli, in which the MutHLS system sensitizes Dam− mutants to DNA-injuring agents, suggested that bile might cause DNA damage. In support of this hypothesis, we show that bile induces the SOS response in S. enterica and increases the frequency of point mutations and chromosomal rearrangements. Mutations in mutH, mutL, or mutS cause partial relief of virulence attenuation in a Dam− background (50- to 100-fold by the oral route and 10-fold intraperitoneally), suggesting that an active MutHLS system reduces the ability of Salmonella Dam− mutants to cope with DNA-damaging agents (bile and others) encountered during the infection process. The DNA-damaging ability of bile under laboratory conditions raises the possibility that the phenomenon may be relevant in vivo, since high bile concentrations are found in the gallbladder, the niche for chronic Salmonella infections. PMID:15611156

  9. Quercetin protection against ciprofloxacin induced liver damage in rats.

    PubMed

    Taslidere, E; Dogan, Z; Elbe, H; Vardi, N; Cetin, A; Turkoz, Y

    2016-01-01

    Ciprofloxacin is a common, broad spectrum antibacterial agent; however, evidence is accumulating that ciprofloxacin may cause liver damage. Quercetin is a free radical scavenger and antioxidant. We investigated histological changes in hepatic tissue of rats caused by ciprofloxacin and the effects of quercetin on these changes using histochemical and biochemical methods. We divided 28 adult female Wistar albino rats into four equal groups: control, quercetin treated, ciprofloxacin treated, and ciprofloxacin + quercetin treated. At the end of the experiment, liver samples were processed for light microscopic examination and biochemical measurements. Sections were prepared and stained with hematoxylin and eosin, and a histopathologic damage score was calculated. The sections from the control group appeared normal. Hemorrhage, inflammatory cell infiltration and intracellular vacuolization were observed in the ciprofloxacin group. The histopathological findings were reduced in the group treated with quercetin. Significant differences were found between the control and ciprofloxacin groups, and between the ciprofloxacin and ciprofloxacin + quercetin groups. Quercetin administration reduced liver injury caused by ciprofloxacin in rats. We suggest that quercetin may be useful for preventing ciprofloxacin induced liver damage.

  10. Renal tissue damage induced by focused shock waves

    NASA Astrophysics Data System (ADS)

    Ioritani, N.; Kuwahara, M.; Kambe, K.; Taguchi, K.; Saitoh, T.; Shirai, S.; Orikasa, S.; Takayama, K.; Lush, P. A.

    1990-07-01

    Biological evidence of renal arterial wall damage induced by the microjet due to shock wave-cavitation bubble interaction was demonstrated in living dog kidneys. We also intended to clarify the mechanism of renal tissue damage and the effects of different conditions of shock wave exposure (peak pressure of focused area, number of shots, exposure rate) on the renal tissue damage in comparison to stone disintegration. Disruption of arterial wall was the most remarkable histological change in the focused area of the kidneys. This lesion appeared as if the wall had been punctured by a needle. Large hematoma formation in the renal parenchym, and interstitial hemorrhage seemed to be the results of the arterial lesion. This arterial disorder also led to ischemic necrosis of the tubules surrounding the hematoma. Micro-angiographic examination of extracted kidneys also proved such arterial puncture lesions and ischemic lesions. The number of shots required for model stone disintegration was not inversely proportional to peak pressure. It decreased markedly when peak pressure was above 700 bar. Similarly thenumber of shots for hematoma formation was not inversely proportional to peak pressure, however, this decreased markedly above 500 bar. These results suggested that a hematoma could be formed under a lower peak pressure than that required for stone disintegration.

  11. Photodynamic therapy induced vascular damage: an overview of experimental PDT

    NASA Astrophysics Data System (ADS)

    Wang, W.; Moriyama, L. T.; Bagnato, V. S.

    2013-02-01

    Photodynamic therapy (PDT) has been developed as one of the most important therapeutic options in the treatment of cancer and other diseases. By resorting to the photosensitizer and light, which convert oxygen into cytotoxic reactive oxygen species (ROS), PDT will induce vascular damage and direct tumor cell killing. Another consequence of PDT is the microvascular stasis, which results in hypoxia and further produces tumor regression. To improve the treatment with PDT, three promising strategies are currently attracting much interest: (1) the combination of PDT and anti-angiogenesis agents, which more effectively prevent the proliferation of endothelial cells and the formation of new blood vessels; (2) the nanoparticle-assisted delivery of photosensitizer, which makes the photosensitizer more localized in tumor sites and thus renders minimal damage to the normal tissues; (3) the application of intravascular PDT, which can avoid the loss of energy during the transmission and expose the target area directly. Here we aim to review the important findings on vascular damage by PDT on mice. The combination of PDT with other approaches as well as its effect on cancer photomedicine are also reviewed.

  12. Simulation of ion induced radiation damage in cells

    NASA Astrophysics Data System (ADS)

    Friedland, W.; Jacob, P.; Paretzke, H. G.; Ottolenghi, A.; Ballarini, F.; Dingfelder, M.

    The biophysical simulation code PARTRAC has been used in several studies of DNA damage induced by various radiation qualities including photons electrons protons alphas and ions heavier than alpha particles Ion-electron interaction cross sections are taken from isotachic protons scaled by Z eff 2 with the effective charge calculated according to the Barkas formula Recently ion type dependent angular distributions were introduced for intermediate secondary electron energies taking into account the different kinematic scaling of the constituents of the electron spectra Calculated stopping powers radial dose distributions and secondary electron spectra were found in good agreement with available experimental and theoretical results Radiation damage to DNA is determined in PARTRAC by superposition of the calculated track structures with a DNA target model taking into account direct effects from coincidences of ionisations and atoms within the DNA helix as well as indirect effects due to interactions of OH radicals produced in water surrounding the DNA For a simulation of radiation effects in human cells this target model comprises several genomic structure levels from the DNA double-helix up to chromosomes Calculated DNA damage due to irradiation of human fibroblast cells by ions of boron nitrogen and neon was compared to corresponding experimental data The calculated total yield of DSB per dose showed saturation behaviour with an RBE of about 2 whereas experimental data had a decreasing tendency with increasing LET to RBE values

  13. Bee products prevent agrichemical-induced oxidative damage in fish.

    PubMed

    Ferreira, Daiane; Rocha, Helio Carlos; Kreutz, Luiz Carlos; Loro, Vania Lucia; Marqueze, Alessandra; Koakoski, Gessi; da Rosa, João Gabriel Santos; Gusso, Darlan; Oliveira, Thiago Acosta; de Abreu, Murilo Sander; Barcellos, Leonardo José Gil

    2013-01-01

    In southern South America and other parts of the world, aquaculture is an activity that complements agriculture. Small amounts of agrichemicals can reach aquaculture ponds, which results in numerous problems caused by oxidative stress in non-target organisms. Substances that can prevent or reverse agrichemical-induced oxidative damage may be used to combat these effects. This study includes four experiments. In each experiment, 96 mixed-sex, 6-month-old Rhamdia quelen (118±15 g) were distributed into eight experimental groups: a control group that was not exposed to contaminated water, three groups that were exposed to various concentrations of bee products, three groups that were exposed to various concentrations of bee products plus tebuconazole (TEB; Folicur 200 CE™) and a group that was exposed to 0.88 mg L(-1) of TEB alone (corresponding to 16.6% of the 96-h LC50). We show that waterborne bee products, including royal jelly (RJ), honey (H), bee pollen (BP) and propolis (P), reversed the oxidative damage caused by exposure to TEB. These effects were likely caused by the high polyphenol contents of these bee-derived compounds. The most likely mechanism of action for the protective effects of bee products against tissue oxidation and the resultant damage is that the enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) are increased.

  14. Islet alone versus islet after kidney transplantation: metabolic outcomes and islet graft survival.

    PubMed

    Deng, Shaoping; Markmann, James F; Rickels, Micheal; Yeh, Heidi; Kim, James I; Lian, Moh-Moh; Gu, Yi; Markmann, Eileen; Palanjian, Maral; Barker, Clyde F; Naji, Ali

    2009-09-27

    Isolated islet transplantation with infusions from two to three donor pancreata and Edmonton immunosuppression consistently achieves insulin independence in patients with type 1 diabetes. The success of this protocol has been attributed to a novel combination of immunosuppressive agents and avoidance of steroids; however, the outcome of islet transplantation may differ in kidney transplant recipients who are already immunosuppressed. We compared the metabolic outcomes and graft survival of islet transplantation in our program where nine patients underwent islet transplantation alone treated with Edmonton immunosuppression and eight patients received islet after kidney (IAK) transplants under standard kidney transplant immunosuppression often including steroids. Transplants in the IAK and islet transplantation alone setting demonstrated similar islet potency (islet equivalents/unit insulin reduction) and recipients from both groups routinely gained insulin independence, functional islet mass, and duration of graft survival, however, seemed superior in the IAK group. These results suggest that better islet graft function and survival may be attained using non-Edmonton rather than Edmonton immunosuppression and can include maintenance steroid therapy.

  15. Differential sensitivity to beta-cell secretagogues in cultured rat pancreatic islets exposed to human interleukin-1 beta.

    PubMed

    Eizirik, D L; Sandler, S; Hallberg, A; Bendtzen, K; Sener, A; Malaisse, W J

    1989-08-01

    The early stages of insulin-dependent diabetes mellitus are characterized by a selective inability to secrete insulin in response to glucose, coupled to a better response to nonnutrient secretagogues. The deficient glucose response may be a result of the autoimmune process directed toward the beta-cells. Interleukin-1 (IL-1) has been suggested to be one possible mediator of immunological damage of the beta-cells. In the present study we characterized the sensitivity of beta-cells to different secretagogues after human recombinant IL-1 beta (rIL-1 beta) exposure. Furthermore, experiments were performed to clarify the biochemical mechanisms behind the defective insulin response observed in these islets. Rat pancreatic islets were isolated and kept in tissue culture (medium RPMI-1640 plus 10% calf serum) for 5 days. The islets were subsequently exposed to 60 pM human recombinant IL-1 beta during 48 h in the same culture conditions as above and examined immediately after IL-1 exposure. The rIL-1 beta-treated islets showed a marked reduction of glucose-stimulated insulin release. Stimulation with arginine plus different glucose concentrations, and leucine plus glutamine partially counteracted the rIL-1 beta-induced reduction of insulin release. The activities of the glycolytic enzymes hexokinase, glucokinase, and glyceraldehyde 3-phosphate dehydrogenase, were similar in control and IL-1-exposed islets. Treatment with IL-1 also did not impair the activities of NADH+- and NADPH+-dependent glutamate dehydrogenase, glutamate-aspartate transaminase, glutamate-alanine transaminase, citrate synthase, and NAD+-linked isocitrate dehydrogenase. The oxidation of D-[6-14C]glucose and L-[U-14C]leucine were decreased by 50% in IL-1-treated islets. Furthermore, there was a significant decrease in the ratios of [2-14C]pyruvate oxidation/[1-14C]pyruvate decarboxylation and L-[U-14C]leucine oxidation/L-[1-14C]leucine decarboxylation, indicating that IL-1 decreases the proportion of

  16. Solvent effect induced solute damage in an organic inner salt.

    PubMed

    Shui, Min; Jin, Xiao; Li, Zhongguo; Yang, Junyi; Shi, Guang; Zhang, Xueru; Wang, Yuxiao; Yang, Kun; Wei, Tai-huei; Song, Yinglin

    2010-12-20

    Nonlinear absorption of a newly synthesized organic inner salt Ge-150 dissolved in four different solvents (DMF, DMSO, acetonitrile and acetone) is investigated by the Z-scan technique with both nanosecond and picosecond pulses. When pulse energy surpasses a threshold and pulse-to-pulse separation is shorter than a characteristic time, all the four solutions show absorption weakening induced by cross-pulse effects in the picosecond regime. However, only two of them (Ge-150 dissolved in DMF and DMSO) show this weakening in the nanosecond regime. By conducting a simple verification experiment, we verify this absorption weakening is induced by solute damage related to solvent effect rather than solute migration. A simple theoretical model is proposed to interpret the experimental phenomenon.

  17. Comparative DNA damage and repair induced by misonidazole, CB 1954 and RSU 1069.

    PubMed

    Dale, L D; Widdick, D A; Edwards, D I; Biol, G I

    1989-04-01

    We have studied the ability of CB 1954, misonidazole, and RSU 1069 to induce biologically relevant DNA damage in single- and double-stranded phi X174 DNA under oxic, anoxic, and anoxic reductive conditions using a double transfection technique. In addition, the ability of the three drugs to induce the SOS repair response in E. coli under the same conditions was measured. Whereas the relative order of DNA damage was RSU 1069 greater than CB 1954 greater than misonidazole the order in inducing SOS repair was RSU 1069 greater than misonidazole greater than CB 1954. Drug-induced damage by RSU 1069 involves enhanced damage by endonuclease III suggesting drug-induced pyrimidine damage. There appears to be no correlation between drug-induced damage and the degree of SOS repair induction. Thus it appears that enzymes other than, or in addition to, those of the SOS repair system are involved in the repair of DNA damage induced by these drugs.

  18. Update on Islet Transplantation

    PubMed Central

    McCall, Michael; James Shapiro, A.M.

    2012-01-01

    Clinical islet transplantation has progressed considerably over the past 12 years, and >750 patients with type 1 diabetes have received islet transplants internationally over this time. Many countries are beginning to accept the transition from research to accepted and funded clinical care, especially for patients with brittle control that cannot be stabilized by more conventional means. Major challenges remain, including the need for more than one donor, and the requirement for potent, chronic immunosuppression. Combining immunological tolerance both to allo- and autoantigens, and a limitless expandable source of stem cell- or xenograft-derived insulin-secreting cells represent remaining hurdles in moving this effective treatment to a potential cure for all those with type 1 or 2 diabetes. PMID:22762022

  19. Pulsed light induced damages in Listeria innocua and Escherichia coli.

    PubMed

    Kramer, B; Wunderlich, J; Muranyi, P

    2015-10-01

    Pulsed light (PL) is an upcoming nonthermal decontamination technology mainly used for surface sterilization. The objective of this study was to investigate the extent of cellular damage caused by PL treatments of Listeria innocua and Escherichia coli on a polysaccharide surface in order to gain knowledge about the main inactivation pathways. The impact of PL on the cellular ATP level was investigated as well as the bacterial ability to take up fluorescently labelled glucose (2-NBDG). Furthermore, the extent of DNA damages was assessed by qPCR. The ability of L. innocua and E. coli to photorepair under artificial daylight exposure was quantified. Finally, the induction of reactive oxygen species (ROS) and lipid peroxidation were studied by fluorometric detection of ROS and thiobarbituric acid reactive substances (TBARS). It is shown that intracellular ATP levels and glucose uptake ability do not correlate with the immediate loss of bacterial reproducibility, which indicates that cellular activity and energy may remain on a relatively high level, although growth on tryptic soy agar is not observable. Sequence specific investigation of PL induced DNA damages by qPCR revealed distinct differences between L. innocua and E. coli although the observed inactivation efficacy of PL by the culture based method was similar. Photoreactivation has been observed for both bacteria, a higher recovery rate of up to 2 log was seen in case of E. coli. Intracellular ROS and lipid peroxides were both detectable at relatively high fluencies with E. coli so the contribution of oxidative damage to microbial inactivation of PL cannot be excluded. Escherichia coli as well as L. innocua cells have proven to maintain residual cellular activity after having been exposed to PL even when they are not able to reproduce any more. High proportions of sublethal damages were also obvious with regard to occurring photoreactivation. The destruction of bacterial DNA seems to be the primary

  20. Anchor-induced chondral damage in the hip.

    PubMed

    Matsuda, Dean K; Bharam, Srino; White, Brian J; Matsuda, Nicole A; Safran, Marc

    2015-01-01

    The purpose of this study is to investigate the outcomes from anchor-induced chondral damage of the hip, both with and without frank chondral penetration. A multicenter retrospective case series was performed of patients with chondral deformation or penetration during initial hip arthroscopic surgery. Intra-operative findings, post-surgical clinical courses, hip outcome scores and descriptions of arthroscopic treatment in cases requiring revision surgery and anchor removal are reported. Five patients (three females) of mean age 32 years (range, 16-41 years) had documented anchor-induced chondral damage with mean 3.5 years (range, 1.5-6.0 years) follow-up. The 1 o'clock position (four cases) and anterior and mid-anterior portals (two cases each) were most commonly implicated. Two cases of anchor-induced acetabular chondral deformation without frank penetration had successful clinical and radiographic outcomes, while one case progressed from deformation to chondral penetration with clinical worsening. Of the cases that underwent revision hip arthroscopy, all three had confirmed exposed hard anchors which were removed. Two patients have had clinical improvement and one patient underwent early total hip arthroplasty. Anchor-induced chondral deformation without frank chondral penetration may be treated with close clinical and radiographic monitoring with a low threshold for revision surgery and anchor removal. Chondral penetration should be treated with immediate removal of offending hard anchor implants. Preventative measures include distal-based portals, small diameter and short anchors, removable hard anchors, soft suture-based anchors, curved drill and anchor insertion instrumentation and attention to safe trajectories while visualizing the acetabular articular surface.

  1. The p75 Neurotrophin Receptor Is Required for the Major Loss of Sympathetic Nerves From Islets Under Autoimmune Attack

    PubMed Central

    Mei, Qi; Bornfeldt, Karin E.; Hackney, Daryl J.; Mundinger, Thomas O.

    2014-01-01

    Our goal was to determine the role of the p75 neurotrophin receptor (p75NTR) in the loss of islet sympathetic nerves that occurs during the autoimmune attack of the islet. The islets of transgenic (Tg) mice in which β-cells express a viral glycoprotein (GP) under the control of the insulin promotor (Ins2) were stained for neuropeptide Y before, during, and after virally induced autoimmune attack of the islet. Ins2-GPTg mice injected with lymphocytic choriomeningitis virus (LCMV) lost islet sympathetic nerves before diabetes development but coincident with the lymphocytic infiltration of the islet. The nerve loss wasmarked and islet-selective. Similar nerve loss, chemically induced, was sufficient to impair sympathetically mediated glucagon secretion. In contrast, LCMV-injected Ins2-GPTg mice lacking the p75NTR retained most of their islet sympathetic nerves, despite both lymphocytic infiltration and development of diabetes indistinguishable from that of p75NTR wild-type mice. We conclude that an nducible autoimmune attack of the islet causes a marked and islet-selective loss of sympathetic nerves that precedes islet collapse and hyperglycemia. The p75NTR mediates this nerve loss but plays no role in mediating the loss of islet β-cells or the subsequent diabetes. p75NTR-mediated nerve loss may contribute to the impaired glucose counterregulation seen in type 1 diabetes. PMID:24608438

  2. Laser induced damage in optical materials: tenth ASTM symposium.

    PubMed

    Glass, A J; Guenther, A H

    1979-07-01

    The tenth annual Symposium on Optical Materials for High Power Lasers (Boulder Damage Symposium) was held at the National Bureau of Standards in Boulder, Colorado, 12-14 September 1978. The symposium was held under the auspices of ASTM Committee F-1, Subcommittee on Laser Standards, with the joint sponsorship of NBS, the Defense Advanced Research Project Agency, the Department of Energy, and the Office of Naval Research. About 175 scientists attended, including representatives of the United Kingdom, France, Canada, Japan, West Germany, and the Soviet Union. The symposium was divided into sessions concerning the measurement of absorption characteristics, bulk material properties, mirrors and surfaces, thin film damage, coating materials and design, and breakdown phenomena. As in previous years, the emphasis of the papers presented was directed toward new frontiers and new developments. Particular emphasis was given to materials for use from 10.6 microm to the UV region. Highlights included surface characterization, thin film-substrate boundaries, and advances in fundamental laser-matter threshold interactions and mechanisms. The scaling of damage thresholds with pulse duration, focal area, and wavelength was also discussed. In commemoration of the tenth symposium in this series, a number of comprehensive review papers were presented to assess the state of the art in various facets of laser induced damage in optical materials. Alexander J. Glass of Lawrence Livermore Laboratory and Arthur H. Guenther of the Air Force Weapons Laboratory were co-chairpersons. The eleventh annual symposium is scheduled for 30-31 October 1979 at the National Bureau of Standards, Boulder, Colorado.

  3. Allicin has significant effect on autoimmune anti-islet cell antibodies in type 1 diabetic rats.

    PubMed

    Osman, Muhamed; Adnan, Ariza; Salmah Bakar, Nor; Alashkham, Fatma

    2012-12-01

    The research purpose was to experimentally investigate the effect of allicin administration on the levels of main type 1 diabetes (IDDM) autoantibodies which are anti-islet cell antibodies (ICA) with an attempt to find a relation between this immunological effect and histological and/or biochemical findings. We have evaluated, with the help of ELISA kits, the levels of ICA and serum insulin in male Sprague-Dawley rats with Streptozotocin-induced IDDM in addition to pancreatic histological findings. The four groups (6 rats each) under study received or not different intraperitoneal doses of allicin for a period of 30 days. Daily intraperitoneal administration of allicin (either at as low dose of 8 mg/kg or high dose of 16 mg/kg) for up to 30 days to type 1 diabetic rats effectively reduces levels of anti-islet cell antibodies and in addition, reduced the level of insulin due to damaged Langerhans islet cell was significantly increased in the serum due to a repairing tissue process in pancreatic tissues. These experimental results suggest that allicin treatment has a therapeutic protective effect against autoimmune reactions occurring in IDDM. The data may provide new strategies for using allicin to be recommended as an excellent candidate in the clinical management, control, and prevention of IDDM.

  4. Scaling Relations for Intercalation Induced Damage in Electrodes

    SciTech Connect

    Chen, Chien-Fan; Barai, Pallab; Smith, Kandler; Mukherjee, Partha P.

    2016-04-02

    Mechanical degradation, owing to intercalation induced stress and microcrack formation, is a key contributor to the electrode performance decay in lithium-ion batteries (LIBs). The stress generation and formation of microcracks are caused by the solid state diffusion of lithium in the active particles. Here in this work, scaling relations are constructed for diffusion induced damage in intercalation electrodes based on an extensive set of numerical experiments with a particle-level description of microcrack formation under disparate operating and cycling conditions, such as temperature, particle size, C-rate, and drive cycle. The microcrack formation and evolution in active particles is simulated based on a stochastic methodology. A reduced order scaling law is constructed based on an extensive set of data from the numerical experiments. The scaling relations include combinatorial constructs of concentration gradient, cumulative strain energy, and microcrack formation. Lastly, the reduced order relations are further employed to study the influence of mechanical degradation on cell performance and validated against the high order model for the case of damage evolution during variable current vehicle drive cycle profiles.

  5. Scaling Relations for Intercalation Induced Damage in Electrodes

    DOE PAGES

    Chen, Chien-Fan; Barai, Pallab; Smith, Kandler; ...

    2016-04-02

    Mechanical degradation, owing to intercalation induced stress and microcrack formation, is a key contributor to the electrode performance decay in lithium-ion batteries (LIBs). The stress generation and formation of microcracks are caused by the solid state diffusion of lithium in the active particles. Here in this work, scaling relations are constructed for diffusion induced damage in intercalation electrodes based on an extensive set of numerical experiments with a particle-level description of microcrack formation under disparate operating and cycling conditions, such as temperature, particle size, C-rate, and drive cycle. The microcrack formation and evolution in active particles is simulated based onmore » a stochastic methodology. A reduced order scaling law is constructed based on an extensive set of data from the numerical experiments. The scaling relations include combinatorial constructs of concentration gradient, cumulative strain energy, and microcrack formation. Lastly, the reduced order relations are further employed to study the influence of mechanical degradation on cell performance and validated against the high order model for the case of damage evolution during variable current vehicle drive cycle profiles.« less

  6. Scaling Relations for Intercalation Induced Damage in Electrodes

    SciTech Connect

    Chen, Chien-Fan; Barai, Pallab; Smith, Kandler; Mukherjee, Partha P.

    2016-06-01

    Mechanical degradation, owing to intercalation induced stress and microcrack formation, is a key contributor to the electrode performance decay in lithium-ion batteries (LIBs). The stress generation and formation of microcracks are caused by the solid state diffusion of lithium in the active particles. In this work, scaling relations are constructed for diffusion induced damage in intercalation electrodes based on an extensive set of numerical experiments with a particle-level description of microcrack formation under disparate operating and cycling conditions, such as temperature, particle size, C-rate, and drive cycle. The microcrack formation and evolution in active particles is simulated based on a stochastic methodology. A reduced order scaling law is constructed based on an extensive set of data from the numerical experiments. The scaling relations include combinatorial constructs of concentration gradient, cumulative strain energy, and microcrack formation. The reduced order relations are further employed to study the influence of mechanical degradation on cell performance and validated against the high order model for the case of damage evolution during variable current vehicle drive cycle profiles.

  7. HLA sensitization in islet transplantation.

    PubMed

    Rickels, Michael R; Kearns, Jane; Markmann, Eileen; Palanjian, Maral; Markmann, James F; Naji, Ali; Kamoun, Malek

    2006-01-01

    Islet transplantation is an emerging therapy for poorly controlled type 1 diabetes. Currently, islets isolated from multiple donors not HLA-matched to recipients are usually required to achieve insulin-independence. Subsequent HLA sensitization is common following a reduction or discontinuation of immunosuppressive drugs and may be responsible for deterioration in islet graft function. Based on the evidence available to date concerning HLA sensitization in islet transplant recipients, we recommend that future islet transplantation protocols consider the following: (1) minimizing the number of islet donors by, for example, infusing high quality islet preparations of sufficient yield from a single donor rather than pooling islet preparations from multiple donors since a greater number of HLA class I mismatches appears to be associated with increased risk for sensitization; (2) ensuring negative cross-matching of donor lymphocytes and recipient sera by testing prior to islet infusions; (3) avoiding donor-recipient antigen mismatches when an identifiable alloantibody is present pre-transplant (i.e., in the case of a positive PRA pretransplant) but excluding potential recipients who are highly sensitized (e.g., have a PRA > or = 20%); and (4) performing an assessment for HLA sensitization using a sensitive flow cytometric method for alloantibody detection any time there is a reduction in immunosuppressant drug levels or worsening of metabolic control.

  8. Glucose-induced cytosolic pH changes in beta-cells and insulin secretion are not causally related: studies in islets lacking the Na+/H+ exchangeR NHE1.

    PubMed

    Stiernet, Patrick; Nenquin, Myriam; Moulin, Pierre; Jonas, Jean-Christophe; Henquin, Jean-Claude

    2007-08-24

    The contribution of Na(+)/H(+) exchange (achieved by NHE proteins) to the regulation of beta-cell cytosolic pH(c), and the role of pH(c) changes in glucose-induced insulin secretion are disputed and were examined here. Using real-time PCR, we identified plasmalemmal NHE1 and intracellular NHE7 as the two most abundant NHE isoforms in mouse islets. We, therefore, compared insulin secretion, cytosolic free Ca(2+) ([Ca(2+)](c)) and pH(c) in islets from normal mice and mice bearing an inactivating mutation of NHE1 (Slc9A1-swe/swe). The experiments were performed in HCO(-)(3)/CO(2) or HEPES/NaOH buffers. PCR and functional approaches showed that NHE1 mutant islets do not express compensatory pH-regulating mechanisms. NHE1 played a greater role than HCO(-)(3)-dependent mechanisms in the correction of an acidification imposed by a pulse of NH(4)Cl. In contrast, basal pH(c) (in low glucose) and the alkalinization produced by high glucose were independent of NHE1. Dimethylamiloride, a classic blocker of Na(+)/H(+) exchange, did not affect pH(c) but increased insulin secretion in NHE1 mutant islets, indicating unspecific effects. In control islets, glucose similarly increased [Ca(2+)](c) and insulin secretion in HCO(-)(3) and HEPES buffer, although pH(c) changed in opposite directions. The amplification of insulin secretion that glucose produces when [Ca(2+)](c) is clamped at an elevated level by KCl was also unrelated to pH(c) and pH(c) changes. All effects of glucose on [Ca(2+)](c) and insulin secretion proved independent of NHE1. In conclusion, NHE1 protects beta-cells against strong acidification, but has no role in stimulus-secretion coupling. The changes in pH(c) produced by glucose involve HCO(-)(3)-dependent mechanisms. Variations in beta-cell pH(c) are not causally related to changes in insulin secretion.

  9. The Study of Non-Viral Nanoscale Delivery Systems for Islet Transplantation

    NASA Astrophysics Data System (ADS)

    Gutierrez, Diana

    Due to safety concerns associated with using viral systems clinically to expand islet cells and make them available to many more patients, significant emphasis has been placed on producing a safe and effective non-viral delivery system for biological research and gene therapy. To obtain this goal, we propose the use of an innovative technology that utilizes gold nanoparticles (AuNPs) as a non-viral method of delivery. Our laboratory was one of the first to describe the use of AuNPs in human islets and observe AuNPs can penetrate into the core of islets to deliver a gene to the vast majority of the cells, without damaging the cell. Gold nanoparticles proved to be a biocompatible delivery system both in vitro and in vivo. Thus far, gene therapy and molecular biology have focused primarily on delivering DNA of a specific gene into cells. The risk of this approach is that the DNA can be permanently incorporated into the genome and lead to damages in the cell that could result in overexpression of cancerous tumor cells. This risk does not exist with the use of mRNA. Many researchers believe mRNA is too unstable to be used as a molecular tool to overexpress specific proteins. With advances in nanotechnology, and better understanding of the translation process, methods have been developed that allow for expression of specific proteins by intracellular delivery of protein-encoding mRNA. We used AuNPs conjugated to mCherry mRNA to establish a proof of concept of the feasibility of using AuNP-mRNA to achieve increased expression of a specific protein within cells. To do this, we conjugated mCherry mRNA to AuNPs and tested the feasibility for increasing delivery efficacy and preserve functionality of human pancreatic islets. We believe that with this novel technology we can create AuNPs that allow specific mRNA to enter islets and lead to the production of a specific protein within the cell, with the aim to induce beta cell proliferation. In a previous experiment with single

  10. TRPM2 channels mediate acetaminophen-induced liver damage

    PubMed Central

    Kheradpezhouh, Ehsan; Ma, Linlin; Morphett, Arthur; Barritt, Greg J.; Rychkov, Grigori Y.

    2014-01-01

    Acetaminophen (paracetamol) is the most frequently used analgesic and antipyretic drug available over the counter. At the same time, acetaminophen overdose is the most common cause of acute liver failure and the leading cause of chronic liver damage requiring liver transplantation in developed countries. Acetaminophen overdose causes a multitude of interrelated biochemical reactions in hepatocytes including the formation of reactive oxygen species, deregulation of Ca2+ homeostasis, covalent modification and oxidation of proteins, lipid peroxidation, and DNA fragmentation. Although an increase in intracellular Ca2+ concentration in hepatocytes is a known consequence of acetaminophen overdose, its importance in acetaminophen-induced liver toxicity is not well understood, primarily due to lack of knowledge about the source of the Ca2+ rise. Here we report that the channel responsible for Ca2+ entry in hepatocytes in acetaminophen overdose is the Transient Receptor Potential Melanostatine 2 (TRPM2) cation channel. We show by whole-cell patch clamping that treatment of hepatocytes with acetaminophen results in activation of a cation current similar to that activated by H2O2 or the intracellular application of ADP ribose. siRNA-mediated knockdown of TRPM2 in hepatocytes inhibits activation of the current by either acetaminophen or H2O2. In TRPM2 knockout mice, acetaminophen-induced liver damage, assessed by the blood concentration of liver enzymes and liver histology, is significantly diminished compared with wild-type mice. The presented data strongly suggest that TRPM2 channels are essential in the mechanism of acetaminophen-induced hepatocellular death. PMID:24569808

  11. DNA damage response induced by HZE particles in human cells

    NASA Astrophysics Data System (ADS)

    Chen, David; Aroumougame, Asaithamby

    Convincing evidences indicate that high-linear energy transfer (LET) ionizing radiation (IR) induced complex DNA lesions are more difficult to repair than isolated DNA lesions induced by low-LET IR; this has been associated with the increased RBE for cell killing, chromosomal aberrations, mutagenesis, and carcinogenesis in high energy charged-particle irradiated human cells. We have employed an in situ method to directly monitor induction and repair of clustered DNA lesions at the single-cell level. We showed, consistent with biophysical modeling, that the kinetics of loss of clustered DNA lesions was substantially compromised in human fibroblasts. The unique spatial distribution of different types of DNA lesions within the clustered damages determined the cellular ability to repair these damages. Importantly, examination of metaphase cells derived from HZE particle irradiated cells revealed that the extent of chromosome aberrations directly correlated with the levels of unrepaired clustered DNA lesions. In addition, we used a novel organotypic human lung three-dimensional (3D) model to investigate the biological significance of unrepaired DNA lesions in differentiated lung epithelial cells. We found that complex DNA lesions induced by HZE particles were even more difficult to be repaired in organotypic 3D culture, resulting enhanced cell killing and chromosome aberrations. Our data suggest that DNA repair capability in differentiated cells renders them vulnerable to DSBs, promoting genome instability that may lead to carcinogenesis. As the organotypic 3D model mimics human lung, it opens up new experimental approaches to explore the effect of radiation in vivo and will have important implications for evaluating radiation risk in human tissues.

  12. Interleukin-1 signaling contributes to acute islet compensation

    PubMed Central

    Hajmrle, Catherine; Smith, Nancy; Spigelman, Aliya F.; Dai, Xiaoqing; Senior, Laura; Bautista, Austin; MacDonald, Patrick E.

    2016-01-01

    IL-1β is a well-established inducer of both insulin resistance and impaired pancreatic islet function. Despite this, findings examining IL-1 receptor deficiency or antagonism in in vivo animal models, as well as in clinical studies of type 2 diabetic (T2D) patients, have led to conflicting results, suggesting that the actions of IL-1β on glycemic control may be pleiotropic in nature. In the present work, we find that the ability of IL-1β to amplify glucose-stimulated insulin secretion from human islets correlates with donor BMI. Islets from obese donors are sensitized to the insulinotropic effects of this cytokine, whereas the stimulatory effects of IL-1β are lost in islets from obese T2D patients, suggesting a role for IL-1 signaling in islet compensation. Indeed, mice deficient in IL-1 receptor type I become glucose intolerant more rapidly than their WT littermates and have impaired secretory responses during the acute stages of inflammatory and metabolic stress induced by LPS and high-fat diet, respectively. IL-1β directly enhances β cell insulin secretion by increasing granule docking and soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) complex formation at the plasma membrane. Together, our study highlights the importance of IL-1β signaling in islet compensation to metabolic and inflammatory stress. PMID:27699257

  13. Alterations in beta-islets of Langerhans in alloxan-induced diabetic rats by marine Spirulina platensis.

    PubMed

    Muthuraman, P; Senthilkumar, R; Srikumar, K

    2009-12-01

    Marine Spirulina platensis may potentially influence the metabolic process in animal cells, and the effect of marine Spirulina platensis in normal and alloxan-induced diabetic rats was therefore investigated. Normal and diabetic rats (albino Wistar strain) were orally administered marine Spirulina platensis for 30 days and their blood levels of glucose and insulin and body weight changes were determined. Pancreatic histopathology was also noted. Treatment with marine Spirulina platensis caused significant alterations in the content of these indicators and therefore in the antidiabetic capacity of the treated animals compared to control rats.

  14. Insulin independence following isolated islet transplantation and single islet infusions.

    PubMed

    Markmann, James F; Deng, Shaoping; Huang, Xiaolun; Desai, Niraj M; Velidedeoglu, Ergun H; Lui, Chengyang; Frank, Adam; Markmann, Eileen; Palanjian, Maral; Brayman, Kenneth; Wolf, Bryan; Bell, Ewan; Vitamaniuk, Marko; Doliba, Nicolai; Matschinsky, Franz; Barker, Clyde F; Naji, Ali

    2003-06-01

    To restore islet function in patients whose labile diabetes subjected them to frequent dangerous episodes of hypoglycemic unawareness, and to determine whether multiple transplants are always required to achieve insulin independence. The recent report by the Edmonton group documenting restoration of insulin independence by islet transplantation in seven consecutive patients with type 1 diabetes differed from previous worldwide experience of only sporadic success. In the Edmonton patients, the transplanted islet mass critical for success was approximately more than 9,000 IEq/kg of recipient body weight and required two or three separate transplants of islets isolated from two to four cadaveric donors. Whether the success of the Edmonton group can be recapitulated by others, and whether repeated transplants using multiple donors will be a universal requirement for success have not been reported. The authors report their treatment with islet transplantation of nine patients whose labile type 1 diabetes was characterized by frequent episodes of dangerous hypoglycemia. In each of the seven patients who have completed the treatment protocol (i.e., one or if necessary a second islet transplant), insulin independence has been achieved. In five of the seven patients only a single infusion of islets was required. To date, only one recipient has subsequently lost graft function, after an initially successful transplant. This patient suffered recurrent hyperglycemia 9 months after the transplant. This report confirms the efficacy of the Edmonton immunosuppressive regimen and indicates that insulin independence can often be achieved by a single transplant of sufficient islet mass.

  15. A novel fluorescence imaging approach for comparative measurements of pancreatic islet function in vitro.

    PubMed

    Corbin, Kathryn L; Hall, Thomas E; Haile, Ruth; Nunemaker, Craig S

    2011-01-01

    Pancreatic islet dysfunction is a key element in the development of type 2 diabetes. Determining possible early warning signs of dysfunction is thus important to determining the underlying causes of diabetes. We describe an improved fluorescent imaging approach to detect potential islet dysfunction. Using Cell Tracker Red (CTR, a mildly thiol-reactive fluorescent probe) to positively label particular islets, we measured intracellular free calcium with fura-2 AM in both CTR-labeled and unlabeled sets of pancreatic islets simultaneously in vitro. This approach enhances sensitivity by controlling for differences in background fluorescence, temperature, and perifusion dynamics. We confirmed that 200 nM CTR produced no spectral overlap with fura-2 and no significant physiological effects in selective tests of islet function. To demonstrate the utility of dual-labeling, we compared untreated islets with islets pretreated with low-dose pro-inflammatory cytokines (IL-6 + IL-1B) to induce mild dysfunction. We alternated CTR-labeling between control and test islets and identified consistent reductions in the amplitude and trajectory of glucose-stimulated calcium responses (GSCa) among cytokine-treated islets that were independent of labeling. Observations were verified using a MATLAB program specifically designed to identify key features in the GSCa. Our findings thus demonstrate the utility of CTR-labeling in identifying islet dysfunction and propose that this technique can be adapted for other cells and tissues.

  16. Imatinib prevents beta cell death in vitro but does not improve islet transplantation outcome.

    PubMed

    King, Aileen J F; Griffiths, Lisa A; Persaud, Shanta J; Jones, Peter M; Howell, Simon L; Welsh, Nils

    2016-05-01

    Introduction Improving islet transplantation outcome could not only bring benefits to individual patients but also widen the patient pool to which this life-changing treatment is available. Imatinib has previously been shown to protect beta cells from apoptosis in a variety of in vitro and in vivo models. The aim of this study was to investigate whether imatinib could be used to improve islet transplantation outcome. Methods Islets were isolated from C57Bl/6 mice and pre-cultured with imatinib prior to exposure to streptozotocin and cytokines in vitro. Cell viability and glucose-induced insulin secretion were measured. For transplantation experiments, islets were pre-cultured with imatinib for either 72 h or 24 h prior to transplantation into streptozotocin-diabetic C57Bl/6 mice. In one experimental series mice were also administered imatinib after islet transplantation. Results Imatinib partially protected islets from beta cell death in vitro. However, pre-culturing islets in imatinib or administering the drug to the mice in the days following islet transplantation did not improve blood glucose concentrations more than control-cultured islets. Conclusion Although imatinib protected against beta cell death from cytokines and streptozotocin in vitro, it did not significantly improve syngeneic islet transplantation outcome.

  17. Imatinib prevents beta cell death in vitro but does not improve islet transplantation outcome

    PubMed Central

    Griffiths, Lisa A.; Persaud, Shanta J.; Jones, Peter M.; Howell, Simon L.; Welsh, Nils

    2016-01-01

    Introduction Improving islet transplantation outcome could not only bring benefits to individual patients but also widen the patient pool to which this life-changing treatment is available. Imatinib has previously been shown to protect beta cells from apoptosis in a variety of in vitro and in vivo models. The aim of this study was to investigate whether imatinib could be used to improve islet transplantation outcome. Methods Islets were isolated from C57Bl/6 mice and pre-cultured with imatinib prior to exposure to streptozotocin and cytokines in vitro. Cell viability and glucose-induced insulin secretion were measured. For transplantation experiments, islets were pre-cultured with imatinib for either 72 h or 24 h prior to transplantation into streptozotocin-diabetic C57Bl/6 mice. In one experimental series mice were also administered imatinib after islet transplantation. Results Imatinib partially protected islets from beta cell death in vitro. However, pre-culturing islets in imatinib or administering the drug to the mice in the days following islet transplantation did not improve blood glucose concentrations more than control-cultured islets. Conclusion Although imatinib protected against beta cell death from cytokines and streptozotocin in vitro, it did not significantly improve syngeneic islet transplantation outcome. PMID:26953716

  18. Earthquake-induced Landslidingand Ground Damage In New Zealand

    NASA Astrophysics Data System (ADS)

    Hancox, G. T.; Perrin, N. D.; Dellow, G. D.

    A study of landsliding caused by 22 historical earthquakes in New Zealand was completed at the end of 1997 (Hancox et al., 1997). The main aims of that study were to determine: (a) the nature and extent of landsliding and other ground damage (sand boils, subsidence and lateral spreading due to soil liquefaction) caused by historical earthquakes; (b) relationships between landsliding and earthquake magnitude, epicentre, faulting, geology and topography; (c) improved environmental criteria and ground classes for assigning MM intensities and seismic hazard assessments in N.Z. The data and results of the 1997 study have recently been summarised and expanded (Hancox et al., in press), and are described in this paper. Relationships developed from these studies indicate that the minimum magnitude for earthquake-induced landsliding (EIL) in N.Z. is about M 5, with significant landsliding occurring at M 6 or greater. The minimum MM intensity for landsliding is MM6, while the most common intensities for significant landsliding are MM7-8. The intensity threshold for soil liquefaction in New Zealand was found to be MM7 for sand boils, and MM8 for lateral spreading, although such effects may also occur at one intensity level lower in highly susceptible materials. The minimum magnitude for liquefaction phenomena in N.Z. is about M 6, compared to M 5 overseas where highly susceptible soils are probably more widespread. Revised environmental response criteria (landsliding, subsidence, liquefaction-induced sand boils and lateral spreading) have also been established for the New Zealand MM Intensity Scale, and provisional landslide susceptibility Ground Classes developed for assigning MM intensities in areas where there are few buildings. Other new data presented include a size/frequency distribution model for earthquake-induced landslides over the last 150 years and a preliminary EIL Opportunity model for N.Z. The application of EIL data and relationships for seismic hazard

  19. DNA damage and mutations induced by arachidonic acid peroxidation.

    PubMed

    Lim, Punnajit; Sadre-Bazzaz, Kianoush; Shurter, Jesse; Sarasin, Alain; Termini, John

    2003-12-30

    Endogenous cellular oxidation of omega6-polyunsaturated fatty acids (PUFAs) has long been recognized as a contributing factor in the development of various cancers. The accrual of DNA damage as a result of reaction with free radical and electrophilic aldehyde products of lipid peroxidation is believed to be involved; however, the genotoxic and mutation-inducing potential of specific membrane PUFAs remains poorly defined. In the present study we have examined the ability of peroxidizing arachidonic acid (AA, 20:4omega6) to induce DNA strand breaks, base modifications, and mutations. The time-dependent induction of single-strand breaks and oxidative base modifications by AA in genomic DNA was quantified using denaturing glyoxal gel electrophoresis. Mutation spectra were determined in XP-G fibroblasts and a repair-proficient line corrected for this defect by c-DNA complementation (XP-G(+)). Mutation frequencies were elevated from approximately 5- to 30-fold over the background following reaction of DNA with AA for various times. The XPG gene product was found to be involved in the suppression of mutations after extended reaction of DNA with AA. Arachidonic acid-induced base substitutions were consistent with the presence of both oxidized and aldehyde base adducts in DNA. The frequency of multiple-base substitutions induced by AA was significantly reduced upon correction for the XPG defect (14% vs 2%, P = 0.0015). Evidence is also presented which suggests that the induced frequency of multiple mutations is lesion dependent. These results are compared to published data for mutations stimulated by alpha,beta-unsaturated aldehydes identified as products of lipid peroxidation.

  20. Chemical-induced DNA damage and human cancer risk.

    PubMed

    Poirier, Miriam C

    2012-10-01

    For more than 200 years human cancer induction has been known to be associated with a large variety of chemical exposures. Most exposures to chemical carcinogens occur as a result of occupation, pollution in the ambient environment, lifestyle choices, or pharmaceutical use. Scientific investigations have revealed that the majority of cancer causing chemicals, or chemical carcinogens, act through "genotoxic" or DNA damaging mechanisms, which involve covalent binding of the chemical to DNA (DNA adduct formation). Cancer-inducing exposures are typically frequent and/or chronic over years, and the accumulation of DNA damage or DNA adduct formation is considered to be a necessary requirement for tumor induction. Studies in animal models have indicated that the ability to reduce DNA damage will also result in reduction of tumor risk, leading to the hypothesis that individuals having the highest levels of DNA adducts may have an increased cancer risk, compared to individuals with the lowest levels of DNA adducts. Here we have reviewed twelve investigations showing 2- to 9-fold increased Relative Risks (RR) or Odds Ratios (OR) for cancer in (the 25% of) individuals having the highest DNA adduct levels, compared to (the 25% of) matched individuals with the lowest DNA adducts. These studies also provided preliminary evidence that multiple types of DNA adducts combined, or DNA adducts combined with other risk factors (such as infection or inflammation), may be associated with more than 10-fold higher cancer risks (RR = 34-60), compared to those found with a single carcinogen. Taken together the data suggest that a reduction in human DNA adduct level is likely to produce a reduction in human cancer risk.

  1. Insulin release and phosphate ion efflux from rat pancreatic islets induced by L-leucine and its nonmetabolizable analogue, 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid.

    PubMed Central

    Freinkel, N; Younsi, C E; Dawson, R M

    1976-01-01

    When isolated rat pancreatic islets that had been labeled with 32P were exposed to 10mM L-leucine in a microperifusion system, there was a transitory, immediate heightened efflux of [32P]phosphate ions. Commencement of the phosphate flush coincided with the first release of insulin, and it occurred in the absence or presence of nonstimulatory levels of glucose (0.5 mg/ml). The effects of leucine upon phosphate efflux were not inhibited by D-mannoheptulose, whereas glucose-induced stimulations were suppressed. The phosphate flush could be induced also by the nonmetabolizable analogue of leucine, 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid. Like insulin release, the effect was stereospecific, with only one of the four stereoisomers, (-)-b-aminobicycloheptane carboxylic acid, being active. Analogue-induced phosphate and insulin release were totally suppressed in a medium containing D2O, but on reversion to H2O the efflux of both hormone and anion occured. It is concluded that insulin secretion from islet beta cells and the release of phosphate ions showed the same specificity for nutrient secretagogues and that both can be triggered even in the absence of exogenous oxidizable fuels. However, the partial dissociation of the dose-response curves for the two phenomena lends support to the contention that the phosphate flush reflects an earlier event in the sequence of stimulus-secretion coupling. PMID:790384

  2. Knee proprioception after exercise-induced muscle damage.

    PubMed

    Torres, R; Vasques, J; Duarte, J A; Cabri, J M H

    2010-06-01

    The purpose of the present study was to investigate whether exercise-induced quadriceps muscle damage affects knee proprioception such as joint position sense (JPS), force sense and the threshold to detect passive movement (TTDPM). Fourteen young men performed sets of eccentric quadriceps contractions at a target of 60% of the maximal concentric peak torque until exhaustion; the exercise was interrupted whenever the subject could not complete two sets. Muscle soreness, JPS, the TTDPM and force sense were examined before the exercise as well as one, 24, 48, 72 and 96 h after exercise. The results were compared using one-way repeated-measure ANOVA. Plasma CK activity, collected at the same times, was analyzed by the Friedman's test to discriminate differences between baseline values and each of the other assessment moments (p<0.05). Relative to the proprioception assessment, JPS at 30 and 70 degrees of knee flexion and force sense were significantly decreased up to 48 h, whereas TTDPM decreased significantly at only one hour and 24 h after exercise, at 30 and 70 degrees of the knee flexion, respectively. The results allow the conclusion that eccentric exercise leading to muscle damage alters joint proprioception, suggesting that there might be impairment in the intrafusal fibres of spindle muscles and in the tendon organs.

  3. Liposomal Antioxidants for Protection against Oxidant-Induced Damage

    PubMed Central

    Suntres, Zacharias E.

    2011-01-01

    Reactive oxygen species (ROS), including superoxide anion, hydrogen peroxide, and hydroxyl radical, can be formed as normal products of aerobic metabolism and can be produced at elevated rates under pathophysiological conditions. Overproduction and/or insufficient removal of ROS result in significant damage to cell structure and functions. In vitro studies showed that antioxidants, when applied directly and at relatively high concentrations to cellular systems, are effective in conferring protection against the damaging actions of ROS, but results from animal and human studies showed that several antioxidants provide only modest benefit and even possible harm. Antioxidants have yet to be rendered into reliable and safe therapies because of their poor solubility, inability to cross membrane barriers, extensive first-pass metabolism, and rapid clearance from cells. There is considerable interest towards the development of drug-delivery systems that would result in the selective delivery of antioxidants to tissues in sufficient concentrations to ameliorate oxidant-induced tissue injuries. Liposomes are biocompatible, biodegradable, and nontoxic artificial phospholipid vesicles that offer the possibility of carrying hydrophilic, hydrophobic, and amphiphilic molecules. This paper focus on the use of liposomes for the delivery of antioxidants in the prevention or treatment of pathological conditions related to oxidative stress. PMID:21876690

  4. Oxidatively induced DNA damage and its repair in cancer.

    PubMed

    Dizdaroglu, Miral

    2015-01-01

    Oxidatively induced DNA damage is caused in living organisms by endogenous and exogenous reactive species. DNA lesions resulting from this type of damage are mutagenic and cytotoxic and, if not repaired, can cause genetic instability that may lead to disease processes including carcinogenesis. Living organisms possess DNA repair mechanisms that include a variety of pathways to repair multiple DNA lesions. Mutations and polymorphisms also occur in DNA repair genes adversely affecting DNA repair systems. Cancer tissues overexpress DNA repair proteins and thus develop greater DNA repair capacity than normal tissues. Increased DNA repair in tumors that removes DNA lesions before they become toxic is a major mechanism for development of resistance to therapy, affecting patient survival. Accumulated evidence suggests that DNA repair capacity may be a predictive biomarker for patient response to therapy. Thus, knowledge of DNA protein expressions in normal and cancerous tissues may help predict and guide development of treatments and yield the best therapeutic response. DNA repair proteins constitute targets for inhibitors to overcome the resistance of tumors to therapy. Inhibitors of DNA repair for combination therapy or as single agents for monotherapy may help selectively kill tumors, potentially leading to personalized therapy. Numerous inhibitors have been developed and are being tested in clinical trials. The efficacy of some inhibitors in therapy has been demonstrated in patients. Further development of inhibitors of DNA repair proteins is globally underway to help eradicate cancer.

  5. Laser induced damage and fracture in fused silica vacuum windows

    SciTech Connect

    Campbell, J.H.; Hurst, P.A.; Heggins, D.D.; Steele, W.A.; Bumpas, S.E.

    1996-11-01

    Laser-induced damage, that initiates catastrophic fracture, has been observed in large ({le}61 cm dia) fused silica lenses that also serve as vacuum barriers in Nova and Beamlet lasers. If the elastic stored energy in the lens is high enough, the lens will fracture into many pieces (implosion). Three parameters control the degree of fracture in the vacuum barrier window: elastic stored energy (tensile stress), ratio of window thickness to flaw depth, and secondary crack propagation. Fracture experiments were conducted on 15-cm dia fused silica windows that contain surface flaws caused by laser damage. Results, combined with window failure data on Beamlet and Nova, were used to develop design criteria for a ``fail-safe`` lens (that may catastrophically fracture but not implode). Specifically, the window must be made thick enough so that the peak tensile stress is less than 500 psi (3.4 MPa) and the thickness/critical flaw size is less than 6. The air leak through the window fracture and into the vacuum must be rapid enough to reduce the load on the window before secondary crack growth occurs. Finite element stress calculations of a window before and immediately following fracture into two pieces show that the elastic stored energy is redistributed if the fragments ``lock`` in place and thereby bridge the opening. In such cases, the peak stresses at the flaw site can increase, leading to further (i.e. secondary) crack growth.

  6. Prevention of chloride-induced corrosion damage to bridges

    SciTech Connect

    Cramer, Stephen D.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Holcomb, Gordon R.; Russell, James H.; Ziomek-Moroz, Margaret; Virmani, Y.P. | Butler, J.T.; Nelson, F.J. | Thompson, N.G.

    2002-01-01

    The annual direct cost of bridge infrastructure corrosion to the U.S. economy is estimated at $8.3 billion, with indirect costs approximately 10 times higher. Of the approximately 600000 bridges in the U.S., between 15% and 20% are listed as ?structurally deficient,? frequently due to corrosion damage. Five technologies are presented for reducing the cost of chloride-induced corrosion damage: (1) conductive coating anodes for cathodic protection of existing reinforce concrete bridges, (2) epoxy-coated rebar (ECR), (3) stainless steel rebar, and (4) high-performance concrete for extending the service life of new structures, and (5) metalizing to provide economical, long-term corrosion protection of steel bridges. Conductive coating anodes and stainless steel rebar represent ongoing work by the Oregon Department of Transportation with final verdicts not expected for years. The ECR and metalizing technology have longer track records and are better established in the bridge construction and protection industry. Application of these technologies is guided by a thorough understanding of their performance, of characteristics of the bridge and its environment, and of the results that are sought.

  7. Islet Neogenesis Associated Protein (INGAP) induces the differentiation of an adult human pancreatic ductal cell line into insulin-expressing cells through stepwise activation of key transcription factors for embryonic beta cell development.

    PubMed

    Assouline-Thomas, Béatrice; Ellis, Daniel; Petropavlovskaia, Maria; Makhlin, Julia; Ding, Jieping; Rosenberg, Lawrence

    2015-01-01

    Regeneration of β-cells in diabetic patients is an important goal of diabetes research. Islet Neogenesis Associated Protein (INGAP) was discovered in the partially duct-obstructed hamster pancreas. Its bioactive fragment, pentadecapeptide 104-118 (INGAP-P), has been shown to reverse diabetes in animal models and to improve glucose homeostasis in patients with diabetes in clinical trials. Further development of INGAP as a therapy for diabetes requires identification of target cells in the pancreas and characterization of the mechanisms of action. We hypothesized that adult human pancreatic ductal cells retain morphogenetic plasticity and can be induced by INGAP to undergo endocrine differentiation. To test this hypothesis, we treated the normal human pancreatic ductal cell line (HPDE) with either INGAP-P or full-length recombinant protein (rINGAP) for short-term periods. Our data show that this single drug treatment induces both proliferation and transdifferentiation of HPDE cells, the latter being characterized by the rapid sequential activation of endocrine developmental transcription factors Pdx-1, Ngn3, NeuroD, IA-1, and MafA and subsequently the expression of insulin at both the mRNA and the protein levels. After 7 days, C-peptide was detected in the supernatant of INGAP-treated cells, reflecting their ability to secrete insulin. The magnitude of differentiation was enhanced by embedding the cells in Matrigel, which led to islet-like cluster formation. The islet-like clusters cells stained positive for nuclear Pdx-1 and Glut 2 proteins, and were expressing Insulin mRNA. These new data suggest that human adult pancreatic ductal cells retain morphogenetic plasticity and demonstrate that a short exposure to INGAP triggers their differentiation into insulin-expressing cells in vitro. In the context of the urgent search for a regenerative and/or cellular therapy for diabetes, these results make INGAP a promising therapeutic candidate.

  8. Tamoxifen inhibits mitochondrial oxidative stress damage induced by copper orthophenanthroline.

    PubMed

    Buelna-Chontal, Mabel; Hernández-Esquivel, Luz; Correa, Francisco; Díaz-Ruiz, Jorge Luis; Chávez, Edmundo

    2016-12-01

    In this work, we studied the effect of tamoxifen and cyclosporin A on mitochondrial permeability transition caused by addition of the thiol-oxidizing pair Cu(2+) -orthophenanthroline. The findings indicate that tamoxifen and cyclosporin A circumvent the oxidative membrane damage manifested by matrix Ca(2+) release, mitochondrial swelling, and transmembrane electrical gradient collapse. Furthermore, it was found that tamoxifen and cyclosporin A prevent the generation of TBARs promoted by Cu(2+) -orthophenanthroline, as well as the inactivation of the mitochondrial enzyme aconitase and disruption of mDNA. Electrophoretic analysis was unable to demonstrate a cross-linking reaction between membrane proteins. Yet, it was found that Cu(2+) -orthophenanthroline induced the generation of reactive oxygen species. It is thus plausible that membrane leakiness is due to an oxidative stress injury.

  9. Sonic-boom-induced building structure responses including damage.

    NASA Technical Reports Server (NTRS)

    Clarkson, B. L.; Mayes, W. H.

    1972-01-01

    Concepts of sonic-boom pressure loading of building structures and the associated responses are reviewed, and results of pertinent theoretical and experimental research programs are summarized. The significance of sonic-boom load time histories, including waveshape effects, are illustrated with the aid of simple structural elements such as beams and plates. Also included are discussions of the significance of such other phenomena as three-dimensional loading effects, air cavity coupling, multimodal responses, and structural nonlinearities. Measured deflection, acceleration, and strain data from laboratory models and full-scale building tests are summarized, and these data are compared, where possible, with predicted values. Damage complaint and claim experience due both to controlled and uncontrolled supersonic flights over communities are summarized with particular reference to residential, commercial, and historic buildings. Sonic-boom-induced building responses are compared with those from other impulsive loadings due to natural and cultural events and from laboratory simulation tests.

  10. That which does not kill us makes us stronger--does Nietzsche's quote apply to islets? A re-evaluation of the passenger leukocyte theory, free radicals, and glucose toxicity in islet cell transplantation.

    PubMed

    Wright, J R; Xu, B-Y

    2014-07-01

    In clinical islet transplantation, isolated islets are embolized into the liver via the portal vein (PV); however, up to 70% of the islets are lost in the first few days after transplantation (i.e., too quickly to be mediated by the adaptive immune system). Part of early loss is due to instant blood-mediated inflammatory reaction, an immune/thrombotic process caused by islets interacting with complement. We have shown that glucose toxicity (GT) also plays a critical role based upon the observation that islets embolized into the PVs of diabetic athymic mice are rapidly lost but, if recipients are not diabetic, the islet grafts persist. Using donor islets resistant to the β-cell toxin streptozotocin, we have shown that intraportal islets engrafted in non-diabetic athymic mice for as little as 3 days will maintain normoglycemia when streptozotocin is administered destroying the recipient's native pancreas β-cells. What is the mechanism of GT in β-cells? Chronic exposure to hyperglycemia over-exerts β-cells and their electron transport chains leak superoxide radicals during aerobic metabolism. Here we reinterpret old data and present some compelling new data supporting a new model of early intraportal islet graft loss. We hypothesize that diabetes stimulates overproduction of superoxide in both the β-cells of the islet grafts and the endothelial cells lining the intraportal microvasculature adjacent to where the embolized islets become lodged. This double dose of oxidant damage stresses both the islets, which are highly susceptible to free radicals because of inherent low levels of scavenging enzymes, and the adjacent hepatic endothelial cells. This, superimposed upon localized endothelial damage caused by embolization, precipitates inflammation and coagulation which further damages islet grafts. Based upon this model, we predict that pre-exposing islets to sub-lethal hyperoxia should up-regulate islet free radical scavenging enzyme levels and promote initial

  11. Effect of nicotinamide on early graft failure following intraportal islet transplantation

    PubMed Central

    Jung, Da-Yeon; Park, Jae Berm; Joo, Sung-Yeon; Joh, Jae-Won; Kwon, Choon-Hyuck; Kwon, Ghee-Young

    2009-01-01

    Intraportal islet transplantation (IPIT) may potentially cure Type 1 diabetes mellitus; however, graft failure in the early post-transplantation period presents a major obstacle. In this study, we tested the ability of nicotinamide to prevent early islet destruction in a syngeneic mouse model. Mice (C57BL/6) with chemically-induced diabetes received intraportal transplants of syngeneic islet tissue in various doses. Islets were cultured for 24 h in medium with or without 10 mM nicotinamide supplementation. Following IPIT, islet function was confirmed by an intraperitoneal glucose tolerance test (IPGTT) and hepatectomy. The effects of nicotinamide were evaluated by blood glucose concentration, serum monocyte chemoattractant protein-1 (MCP-1) concentration, and immunohistology at 3 h and 24 h after IPIT. Among the various islet doses, an infusion of 300 syngeneic islets treated with nicotinamide exhibited the greatest differences in glucose tolerance between recipients of treated and untreated (i.e., control) islets. One day after 300 islet equivalent (IEQ) transplantation, islets treated with nicotinamide were better granulated than the untreated islets (P = 0.01), and the recipients displayed a slight decrease in serum MCP-1 concentration, as compared to controls. After 15 days, recipients of nicotinamide-pretreated islets showed higher levels of graft function (as measured by IPGTT) than controls. The pretreatment also prolonged graft survival (> 100 days) and function; these were confirmed by partial hepatectomy, which led to the recurrence of diabetes. Pretreatment of islet grafts with nicotinamide may prevent their deterioration on the early period following IPIT in a syngeneic mouse model. PMID:19641379

  12. Can pancreatic duct-derived progenitors be a source of islet regeneration?

    SciTech Connect

    Xia, Bing; Zhan, Xiao-Rong; Yi, Ran; Yang, Baofeng

    2009-06-12

    The regenerative process of the pancreas is of interest because the main pathogenesis of diabetes mellitus is an inadequate number of insulin-producing {beta}-cells. The functional mass of {beta}-cells is decreased in type 1 diabetes, so replacing missing {beta}-cells or triggering their regeneration may allow for improved type 1 diabetes treatment. Therefore, expansion of the {beta}-cell mass from endogenous sources, either in vivo or in vitro, represents an area of increasing interest. The mechanism of islet regeneration remains poorly understood, but the identification of islet progenitor sources is critical for understanding {beta}-cell regeneration. One potential source is the islet proper, via the dedifferentiation, proliferation, and redifferentiation of facultative progenitors residing within the islet. Neogenesis, or that the new pancreatic islets can derive from progenitor cells present within the ducts has been reported, but the existence and identity of the progenitor cells have been debated. In this review, we focus on pancreatic ductal cells, which are islet progenitors capable of differentiating into islet {beta}-cells. Islet neogenesis, seen as budding of hormone-positive cells from the ductal epithelium, is considered to be one mechanism for normal islet growth after birth and in regeneration, and has suggested the presence of pancreatic stem cells. Numerous results support the neogenesis hypothesis, the evidence for the hypothesis in the adult comes primarily from morphological studies that have in common the production of damage to all or part of the pancreas, with consequent inflammation and repair. Although numerous studies support a ductal origin for new islets after birth, lineage-tracing experiments are considered the 'gold standard' of proof. Lineage-tracing experiments show that pancreatic duct cells act as progenitors, giving rise to new islets after birth and after injury. The identification of differentiated pancreatic ductal cells as

  13. Efficient Gene Transduction of Dispersed Islet Cells in Culture Using Fiber-Modified Adenoviral Vectors

    PubMed Central

    Hanayama, Hiroyuki; Ohashi, Kazuo; Utoh, Rie; Shimizu, Hirofumi; Ise, Kazuya; Sakurai, Fuminori; Mizuguchi, Hiroyuki; Tsuchiya, Hiroyuki; Okano, Teruo; Gotoh, Mitsukazu

    2015-01-01

    To establish novel islet-based therapies, our group has recently developed technologies for creating functional neo-islet tissues in the subcutaneous space by transplanting monolithic sheets of dispersed islet cells (islet cell sheets). Improving cellular function and viability are the next important challenges for enhancing the therapeutic effects. This article describes the adenoviral vector-mediated gene transduction of dispersed islet cells under culture conditions. Purified pancreatic islets were obtained from Lewis rats and dissociated into single islet cells. Cells were plated onto laminin-5-coated temperature-responsive polymer poly(N-isopropylacrylamide)-immobilized plastic dishes. At 0 h, islet cells were infected for 1 h with either conventional type 5 adenoviral vector (Ad-CA-GFP) or fiber-modified adenoviral vector (AdK7-CA-GFP) harboring a polylysine (K7) peptide in the C terminus of the fiber knob. We investigated gene transduction efficiency at 48 h after infection and found that AdK7-CA-GFP yielded higher transduction efficiencies than Ad-CA-GFP at a multiplicity of infection (MOI) of 5 and 10. For AdK7-CA-GFP at MOI = 10, 84.4 ± 1.5% of islet cells were found to be genetically transduced without marked vector infection-related cellular damage as determined by viable cell number and lactate dehydrogenase (LDH) release assay. After AdK7-CA-GFP infection at MOI = 10, cells remained attached and expanded to nearly full confluency, showing that this adenoviral infection protocol is a feasible approach for creating islet cell sheets. We have shown that dispersed and cultured islet cells can be genetically modified efficiently using fiber-modified adenoviral vectors. Therefore, this gene therapy technique could be used for cellular modification or biological assessment of dispersed islet cells. PMID:26858906

  14. In Vivo Magnetic Resonance Imaging of Small Interfering RNA Nanodelivery to Pancreatic Islets.

    PubMed

    Wang, Ping; Moore, Anna

    2016-01-01

    Pancreatic islet transplantation is a promising therapeutic approach for type 1 diabetes.However, recent advances in islet transplantation are limited by significant graft loss after transplantation. Multiple immunological and nonimmunological factors contribute to this loss. Novel therapies that could target the core reasons for the islet graft loss are desperately needed. Small interfering RNA can be used to inhibit the expression of virtually any gene with single-nucleotide specificity including genes responsible for islet damage. Applying adequate delivery of siRNA molecules to pancreatic islets prior to transplantation holds a great potential for improving the survival of islet grafts. Noninvasive imaging provides means for monitoring the survival of transplanted islets in real time. Here, we summarize the approach that has been developed to deliver siRNA to pancreatic islets in conjunction with tracking of the graft outcome by in vivo magnetic resonance imaging (MRI). We synthesize a nano-sized theranostic agent consisting of magnetic nanoparticles (MN), a reporter for MRI, labeled with Cy5.5 dye for near-infrared fluorescence (NIRF) imaging, and conjugated to siRNA molecule targeting genes that are harmful to islet grafts. Pre-labeling of islets by MN-Cy5.5-siRNA allowed us to monitor the survival of transplanted islet grafts by MRI and NIRF imaging and resulted in efficient silencing of the target genes in vivo. This novel approach combines a therapeutic effect provided by RNA interference technology with in vivo MR imaging and is expected to significantly improve the outcome of islet transplantation in patients with type 1 diabetes.

  15. Role of Oxidative Damage in Radiation-Induced Bone Loss

    NASA Technical Reports Server (NTRS)

    Schreurs, Ann-Sofie; Alwood, Joshua S.; Limoli, Charles L.; Globus, Ruth K.

    2014-01-01

    used an array of countermeasures (Antioxidant diets and injections) to prevent the radiation-induced bone loss, although these did not prevent bone loss, analysis is ongoing to determine if these countermeasure protected radiation-induced damage to other tissues.

  16. OXIDANT CONDITIONING PROTECTS CARTILAGE FROM MECHANICALLY-INDUCED DAMAGE

    PubMed Central

    Ramakrishnan, Prem; Hecht, Benjamin; Pedersen, Doug; Lavery, Matthew; Maynard, Jerry; Buckwalter, Joseph; Martin, James

    2013-01-01

    Articular cartilage degeneration in osteoarthritis has been linked to abnormal mechanical stresses that are known to cause chondrocyte apoptosis and metabolic derangement in in vitro models. Evidence implicating oxidative damage as the immediate cause of these harmful effects suggests that the anti-oxidant defenses of chondrocytes might influence their tolerance for mechanical injury. Based on evidence that anti-oxidant defenses in many cell types are stimulated by moderate oxidant exposure, we hypothesized that oxidant pre-conditioning would reduce acute chondrocyte death and proteoglycan depletion in cartilage explants after exposure to abnormal mechanical stresses. Porcine cartilage explants were treated every 48 hours with tert-butyl hydrogen peroxide (tBHP) at non-lethal concentrations (25, 100, 250, 500 µM) for a varying number of times (1, 2 or 4) prior to a bout of unconfined axial compression (5 MPa, 1 Hz, 1800 cycles). When compared with untreated controls, tBHP had significant positive effects on post-compression viability, lactate production, and proteoglycan losses. Overall, the most effective regime was 100 µM tBHP applied 4 times. RNA analysis revealed significant effects of 100 µM tBHP on gene expression. Catalase, hypoxia-inducible factor-1alpha (HIF-1α), and glyceraldehyde 6-phosphate dehydrogenase (GAPDH) were significantly increased relative to untreated controls in explants treated 4 times with 100 µM tBHP, a regime that also resulted in a significant decrease in matrix metalloproteinase-3 (MMP-3) expression. These findings demonstrate that repeated exposure of cartilage to sub-lethal concentrations of peroxide can moderate the acute effects of mechanical stress, a conclusion supported by evidence of peroxide-induced changes in gene expression that could render chondrocytes more resistant to oxidative damage. PMID:20058262

  17. Pyrosequencing: Applicability for Studying DNA Damage-induced Mutagenesis

    PubMed Central

    Minko, Irina G.; Earley, Lauriel F.; Larlee, Kimberly E.; Lin, Ying-Chih; Lloyd, R. Stephen

    2014-01-01

    Site-specifically modified DNAs are routinely used in the study of DNA damage-induced mutagenesis. These analyses involve the creation of DNA vectors containing a lesion at a predetermined position, DNA replication, and detection of mutations at the target site. The final step has previously required the isolation of individual DNA clones, hybridization with radioactively-labeled probes, and verification of mutations by Sanger sequencing. In search for an alternative procedure that would allow direct quantification of sequence variants in a mixed population of DNA molecules, we evaluated the applicability of pyrosequencing to site-specific mutagenesis assays. The progeny DNAs were analyzed that originated from replication of N6-(deoxy-D-erythro-pentofuranosyl)-2,6-diamino-3,4-dihydro-4-oxo-5-N-methylformamidopyrimidine (MeFapy-dG)-containing vectors in primate cells, with the lesion being positioned in the 5′-GCNGG-3′ sequence context. Pyrosequencing detected ~8% G to T transversions and ~3.5% G to A transitions, a result that was in excellent agreement with frequencies previously measured by the standard procedure [Earley et al., 2013]. However, ~3.5% G to C transversions and ~2.0% deletions could not be detected by pyrosequencing. Consistent with these observations, the sensitivity of pyrosequencing for measuring the single deoxynucleotide variants differed depending on the deoxynucleotide identity, and in the given sequence contexts, was determined to be ~1-2% for A and T and ~5% for C. Pyrosequencing of other DNA isolates that were obtained following replication of MeFapy-dG-containing vectors in primate cells or Escherichia coli, identified several additional limitations. Collectively, our data demonstrated that pyrosequencing can be used for studying DNA damage-induced mutagenesis as an effective complementary experimental approach to current protocols. PMID:24962778

  18. Infection of peripancreatic lymph nodes but not islets precedes Kilham rat virus-induced diabetes in BB/Wor rats.

    PubMed Central

    Brown, D W; Welsh, R M; Like, A A

    1993-01-01

    A parvovirus serologically identified as Kilham rat virus (KRV) reproducibly induces acute type I diabetes in diabetes-resistant BB/Wor rats. The tissue tropism of KRV was investigated by in situ hybridization with a digoxigenin-labelled plasmid DNA probe containing approximately 1.6 kb of the genome of the UMass isolate of KRV. Partial sequencing of the KRV probe revealed high levels of homology to the sequence of minute virus of mice (89%) and to the sequence of H1 (99%), a parvovirus capable of infecting rats and humans. Of the 444 bases sequenced, 440 were shared by H1. KRV mRNA and DNA were readily detected in lymphoid tissues 5 days postinfection but were seldom seen in the pancreas. High levels of viral nucleic acids were observed in the thymus, spleen, and peripancreatic and cervical lymph nodes. The low levels of infection observed in the pancreas involved essentially only endothelial and interstitial cells. Beta cells of the pancreas were not infected with KRV. These findings suggest that widespread infection of peripancreatic and other lymphoid tissues but not pancreatic beta cells by KRV triggers autoimmune diabetes by perturbing the immune system of genetically predisposed BB/Wor rats. Images PMID:8371347

  19. Glucose-induced electrical activities and insulin secretion in pancreatic islet β-cells are modulated by CFTR

    PubMed Central

    Guo, Jing Hui; Chen, Hui; Ruan, Ye Chun; Zhang, Xue Lian; Zhang, Xiao Hu; Fok, Kin Lam; Tsang, Lai Ling; Yu, Mei Kuen; Huang, Wen Qing; Sun, Xiao; Chung, Yiu Wa; Jiang, Xiaohua; Sohma, Yoshiro; Chan, Hsiao Chang

    2014-01-01

    The cause of insulin insufficiency remains unknown in many diabetic cases. Up to 50% adult patients with cystic fibrosis (CF), a disease caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR), develop CF-related diabetes (CFRD) with most patients exhibiting insulin insufficiency. Here we show that CFTR is a regulator of glucose-dependent electrical acitivities and insulin secretion in β-cells. We demonstrate that glucose elicited whole-cell currents, membrane depolarization, electrical bursts or action potentials, Ca2+ oscillations and insulin secretion are abolished or reduced by inhibitors or knockdown of CFTR in primary mouse β-cells or RINm5F β-cell line, or significantly attenuated in CFTR mutant (DF508) mice compared with wild-type mice. VX-809, a newly discovered corrector of DF508 mutation, successfully rescues the defects in DF508 β-cells. Our results reveal a role of CFTR in glucose-induced electrical activities and insulin secretion in β-cells, shed light on the pathogenesis of CFRD and possibly other idiopathic diabetes, and present a potential treatment strategy. PMID:25025956

  20. Important role of heparan sulfate in postnatal islet growth and insulin secretion

    SciTech Connect

    Takahashi, Iwao; Noguchi, Naoya; Nata, Koji; Yamada, Shuhei; Kaneiwa, Tomoyuki; Mizumoto, Shuji; Ikeda, Takayuki; Sugihara, Kazushi; Asano, Masahide; Yoshikawa, Takeo; Yamauchi, Akiyo; Shervani, Nausheen Jamal; Uruno, Akira; Kato, Ichiro; Unno, Michiaki; Sugahara, Kazuyuki; Takasawa, Shin; and others

    2009-05-22

    Heparan sulfate (HS) binds with several signaling molecules and regulates ligand-receptor interactions, playing an essential role in embryonic development. Here we showed that HS was intensively expressed in pancreatic islet {beta}-cells after 1 week of age in mice. The enzymatic removal of HS in isolated islets resulted in attenuated glucose-induced insulin secretion with a concomitant reduction in gene expression of several key components in the insulin secretion machinery. We further depleted islet HS by inactivating the exostosin tumor-like 3 gene specifically in {beta}-cells. These mice exhibited abnormal islet morphology with reduced {beta}-cell proliferation after 1 week of age and glucose intolerance due to defective insulin secretion. These results demonstrate that islet HS is involved in the regulation of postnatal islet maturation and required to ensure normal insulin secretion.

  1. A preclinical evaluation of alternative site for islet allotransplantation

    PubMed Central

    He, Sirong; Yuan, Yujia; Han, Pengfei; Wang, Dan; Chen, Younan; Liu, Jingping; Tian, Bole; Yang, Guang; Yi, Shounan; Gao, Fabao; Zhong, Zhihui; Li, Hongxia; Cheng, Jingqiu; Lu, Yanrong

    2017-01-01

    The bone marrow cavity (BMC) has recently been identified as an alternative site to the liver for islet transplantation. This study aimed to compare the BMC with the liver as an islet allotransplantation site in diabetic monkeys. Diabetes was induced in Rhesus monkeys using streptozocin, and the monkeys were then divided into the following three groups: Group1 (islets transplanted in the liver with immunosuppressant), Group 2 (islets transplanted in the tibial BMC), and Group 3 (islets transplanted in the tibial BMC with immunosuppressant). The C-peptide and blood glucose levels were preoperatively measured. An intravenous glucose tolerance test (IVGTT) was conducted to assess graft function, and complete blood cell counts were performed to assess cell population changes. Cytokine expression was measured using an enzyme-linked immune sorbent assay (ELISA) and MILLIPLEX. Five monkeys in Group 3 exhibited a significantly increased insulin-independent time compared with the other groups (Group 1: 78.2 ± 19.0 days; Group 2: 58.8 ± 17.0 days; Group 3: 189.6 ± 26.2 days) and demonstrated increases in plasma C-peptide 4 months after transplantation. The infusion procedure was not associated with adverse effects. Functional islets in the BMC were observed 225 days after transplantation using the dithizone (DTZ) and insulin/glucagon stains. Our results showed that allogeneic islets transplanted in the BMC of diabetic Rhesus monkeys remained alive and functional for a longer time than those transplanted in the liver. This study was the first successful demonstration of allogeneic islet engraftment in the BMC of non-human primates (NHPs). PMID:28358858

  2. A single-islet microplate assay to measure mouse and human islet insulin secretion.

    PubMed

    Truchan, Nathan A; Brar, Harpreet K; Gallagher, Shannon J; Neuman, Joshua C; Kimple, Michelle E

    2015-01-01

    One complication to comparing β-cell function among islet preparations, whether from genetically identical or diverse animals or human organ donors, is the number of islets required per assay. Islet numbers can be limiting, meaning that fewer conditions can be tested; other islet measurements must be excluded; or islets must be pooled from multiple animals/donors for each experiment. Furthermore, pooling islets negates the possibility of performing single-islet comparisons. Our aim was to validate a 96-well plate-based single islet insulin secretion assay that would be as robust as previously published methods to quantify glucose-stimulated insulin secretion from mouse and human islets. First, we tested our new assay using mouse islets, showing robust stimulation of insulin secretion 24 or 48 h after islet isolation. Next, we utilized the assay to quantify mouse islet function on an individual islet basis, measurements that would not be possible with the standard pooled islet assay methods. Next, we validated our new assay using human islets obtained from the Integrated Islet Distribution Program (IIDP). Human islets are known to have widely varying insulin secretion capacity, and using our new assay we reveal biologically relevant factors that are significantly correlated with human islet function, whether displayed as maximal insulin secretion response or fold-stimulation of insulin secretion. Overall, our results suggest this new microplate assay will be a useful tool for many laboratories, expert or not in islet techniques, to be able to precisely quantify islet insulin secretion from their models of interest.

  3. Impact of Pancreatic Rat Islet Density on Cell Survival during Hypoxia

    PubMed Central

    Rodriguez-Brotons, A.; Bietiger, W.; Peronet, C.; Magisson, J.; Sookhareea, C.; Langlois, A.; Mura, C.; Jeandidier, N.; Pinget, M.; Sigrist, S.; Maillard, E.

    2016-01-01

    In bioartificial pancreases (BP), the number of islets needed to restore normoglycaemia in the diabetic patient is critical. However, the confinement of a high quantity of islets in a limited space may impact islet survival, particularly in regard to the low oxygen partial pressure (PO2) in such environments. The aim of the present study was to evaluate the impact of islet number in a confined space under hypoxia on cell survival. Rat islets were seeded at three different concentrations (150, 300, and 600 Islet Equivalents (IEQ)/cm2) and cultured in normal atmospheric pressure (160 mmHg) as well as hypoxic conditions (15 mmHg) for 24 hours. Cell viability, function, hypoxia-induced changes in gene expression, and cytokine secretion were then assessed. Notably, hypoxia appeared to induce a decrease in viability and increasing islet density exacerbated the observed increase in cellular apoptosis as well as the loss of function. These changes were also associated with an increase in inflammatory gene transcription. Taken together, these data indicate that when a high number of islets are confined to a small space under hypoxia, cell viability and function are significantly impacted. Thus, in order to improve islet survival in this environment during transplantation, oxygenation is of critical importance. PMID:26824040

  4. Both Complexity and Location of DNA Damage Contribute to Cellular Senescence Induced by Ionizing Radiation

    PubMed Central

    Zhang, Xurui; Ye, Caiyong; Sun, Fang; Wei, Wenjun; Hu, Burong; Wang, Jufang

    2016-01-01

    Persistent DNA damage is considered as a main cause of cellular senescence induced by ionizing radiation. However, the molecular bases of the DNA damage and their contribution to cellular senescence are not completely clear. In this study, we found that both heavy ions and X-rays induced senescence in human uveal melanoma 92–1 cells. By measuring senescence associated-β-galactosidase and cell proliferation, we identified that heavy ions were more effective at inducing senescence than X-rays. We observed less efficient repair when DNA damage was induced by heavy ions compared with X-rays and most of the irreparable damage was complex of single strand breaks and double strand breaks, while DNA damage induced by X-rays was mostly repaired in 24 hours and the remained damage was preferentially associated with telomeric DNA. Our results suggest that DNA damage induced by heavy ion is often complex and difficult to repair, thus presents as persistent DNA damage and pushes the cell into senescence. In contrast, persistent DNA damage induced by X-rays is preferentially associated with telomeric DNA and the telomere-favored persistent DNA damage contributes to X-rays induced cellular senescence. These findings provide new insight into the understanding of high relative biological effectiveness of heavy ions relevant to cancer therapy and space radiation research. PMID:27187621

  5. Both Complexity and Location of DNA Damage Contribute to Cellular Senescence Induced by Ionizing Radiation.

    PubMed

    Zhang, Xurui; Ye, Caiyong; Sun, Fang; Wei, Wenjun; Hu, Burong; Wang, Jufang

    2016-01-01

    Persistent DNA damage is considered as a main cause of cellular senescence induced by ionizing radiation. However, the molecular bases of the DNA damage and their contribution to cellular senescence are not completely clear. In this study, we found that both heavy ions and X-rays induced senescence in human uveal melanoma 92-1 cells. By measuring senescence associated-β-galactosidase and cell proliferation, we identified that heavy ions were more effective at inducing senescence than X-rays. We observed less efficient repair when DNA damage was induced by heavy ions compared with X-rays and most of the irreparable damage was complex of single strand breaks and double strand breaks, while DNA damage induced by X-rays was mostly repaired in 24 hours and the remained damage was preferentially associated with telomeric DNA. Our results suggest that DNA damage induced by heavy ion is often complex and difficult to repair, thus presents as persistent DNA damage and pushes the cell into senescence. In contrast, persistent DNA damage induced by X-rays is preferentially associated with telomeric DNA and the telomere-favored persistent DNA damage contributes to X-rays induced cellular senescence. These findings provide new insight into the understanding of high relative biological effectiveness of heavy ions relevant to cancer therapy and space radiation research.

  6. Topical Application of Liposomal Antioxidants for Protection Against CEES Induced Skin Damage

    DTIC Science & Technology

    2007-07-01

    keratinocytes. Task 2: Similar to HD, CEES induces oxidative stress in the skin cells resulting in ROS generation, DNA damaging, protein and lipid oxidation...W81XWH-05-2-0034 TITLE: Topical Application of Liposomal Antioxidants for Protection Against CEES Induced Skin Damage PRINCIPAL...NUMBER Topical Application of Liposomal Antioxidants for Protection Against CEES Induced Skin Damage 5b. GRANT NUMBER W81XWH-05-2-0034 5c. PROGRAM

  7. Exenatide Induces Impairment of Autophagy Flux to Damage Rat Pancreas.

    PubMed

    Li, Zhiqiang; Huang, Lihua; Yu, Xiao; Yu, Can; Zhu, Hongwei; Li, Xia; Han, Duo; Huang, Hui

    2017-01-01

    The study aimed to explore the alteration of autophagy in rat pancreas treated with exenatide. Normal Sprague-Dawley rats and diabetes-model rats induced by 2-month high-sugar and high-fat diet and streptozotocin injection were subcutaneously injected with exenatide, respectively, for 10 weeks, with homologous rats treated with saline as control. Meanwhile, AR42J cells, pancreatic acinar cell line, were cultured with exenatide at doses of 5 pM for 3 days. The pancreas was disposed, and several sections were stained with hematoxylin-eosin. Immunohistochemistry was used to measure the expressions of glucagon-like peptide 1 receptor (GLP-1R) and cysteine-aspartic acid protease-3 in rat pancreas, and Western blot was used to test the expressions of GLP-1R, light chain 3B-I and -II, and p62 in rat pancreas and AR42J cells. The data were expressed as mean (standard deviation) and analyzed by unpaired Student's t-test. Exenatide can induce pathological changes in rat pancreas. The GLP-1R, p62, light chain 3B-II, and cysteine-aspartic acid protease-3 in rat pancreas and AR42J cells treated with exenatide were significantly overexpressed. Exenatide can activate and upregulate its receptor, GLP-1R, then impair autophagy flux and activate apoptosis in the pancreatic acinar cell, thus damaging rat pancreas.

  8. New insights in photoaging, UVA induced damage and skin types.

    PubMed

    Battie, Claire; Jitsukawa, Setsuko; Bernerd, Françoise; Del Bino, Sandra; Marionnet, Claire; Verschoore, Michèle

    2014-10-01

    UVA radiation is the most prevalent component of solar UV radiation; it deeply penetrates into the skin and induces profound alterations of the dermal connective tissue. In recent years, the detrimental effects of UVA radiation were more precisely demonstrated at cellular and molecular levels, using adequate methods to identify biological targets of UVA radiation and the resulting cascade impairment of cell functions and tissue degradation. In particular gene expression studies recently revealed that UVA radiation induces modulation of several genes confirming the high sensitivity of dermal fibroblasts to UVA radiation. The major visible damaging effects of UVA radiation only appear after years of exposure: it has been clearly evidenced that they are responsible for more or less early signs of photoageing and photocarcinogenesis. UVA radiation appears to play a key role in pigmented changes occurring with age, the major sign of skin photoaging in Asians. Skin susceptibility to photoaging alterations also depends on constitutive pigmentation. The skin sensitivity to UV light has been demonstrated to be linked to skin color type.

  9. Nitrous acid induced damage in T7 DNA and phage

    SciTech Connect

    Scearce, L.M.; Masker, W.E.

    1986-05-01

    The response of bacteriophage T7 to nitrous acid damage was investigated. The T7 system allows in vitro mimicry of most aspects of in vivo DNA metabolism. Nitrous acid is of special interest since it has been previously shown to induce deletions and point mutations as well as novel adducts in DNA. T7 phage was exposed to 56 mM nitrous acid at pH 4.6 in vivo, causing a time dependent 98% decrease in survival for each 10 min duration of exposure to nitrous acid. These studies were extended to include examination of pure T7 DNA exposed in vitro to nitrous acid conditions identical to those used in the in vivo survival studies. The treated DNA was dialyzed to remove the nitrous acid and the DNA was encapsulated into empty phage heads. These in vitro packaged phage showed a survival curve analogous to the in vivo system. There was no change in survival when either in vitro or in vivo exposed phage were grown on wild type E. coli or on E. coli strains deficient in DNA repair due to mutations in DNA polymerase I, exonuclease III or a uvrA mutation. Survival was not increased when nitrous acid treated T7 were grown on E. coli induced for SOS repair. In vitro replication of nitrous acid treated DNA showed a time dependent decrease in the total amount of DNA synthesized.

  10. Ischemic Preconditioning Blunts Muscle Damage Responses Induced by Eccentric Exercise.

    PubMed

    Franz, Alexander; Behringer, Michael; Harmsen, Jan-Frieder; Mayer, Constantin; Krauspe, Rüdiger; Zilkens, Christoph; Schumann, Moritz

    2017-08-22

    Ischemic preconditioning (IPC) is known to reduce muscle damage induced by ischemia and reperfusion-injury (I/R-Injury) during surgery. Due to similarities between the pathophysiological formation of I/R-injury and eccentric exercise-induced muscle damage (EIMD), as characterized by an intracellular accumulation of Ca, an increased production of reactive oxygen species and increased pro-inflammatory signaling, the purpose of the present study was to investigate whether IPC performed prior to eccentric exercise may also protect against EIMD. Nineteen healthy men were matched to an eccentric only (ECC) (n=9) or eccentric proceeded by IPC group (IPC+ECC) (n=10). The exercise protocol consisted of bilateral biceps curls (3x10 repetitions at 80% of the concentric 1RM). In IPC+ECC, IPC was applied bilaterally at the upper arms by a tourniquet (200 mmHg) immediately prior to the exercise (3x5 minutes of occlusion, separated by 5 minutes of reperfusion). Creatine Kinase (CK), arm circumference, subjective pain (VAS score) and radial displacement (Tensiomyography, Dm) were assessed before IPC, pre-exercise, post-exercise, 20 minutes-, 2 hours-, 24 hours-, 48 hours- and 72 hours post-exercise. CK differed from baseline only in ECC at 48h (p<0.001) and 72h (p<0.001) post-exercise. After 24h, 48h and 72h, CK was increased in ECC compared to IPC+ECC (between groups: 24h: p=0.004, 48h: p<0.001, 72h: p<0.001). VAS was significantly higher in ECC at 24-72 h post-exercise, when compared to IPC+ECC (between groups: all p<0.001). Dm was decreased on all post-exercise days in ECC (all p<0.001) but remained statistically unchanged in IPC+ECC (between-groups p<0.01). These findings indicate that IPC performed prior to a bout of eccentric exercise of the elbow flexors blunts EIMD and exercise-induced pain, while maintaining the contractile properties of the muscle.

  11. Characteristics of high-peak pulsed laser induced damage to fibers

    NASA Astrophysics Data System (ADS)

    Zhao, Xinghai; Gao, Yang; Xu, Meijian; Duan, Wentao; Yu, Haiwu

    2008-03-01

    The properties of high peak pulsed laser induced damage to fused-silica fibers are investigated using damage experiments. The laser source is Q-switched Nd:YAG pumped dye laser system, the pulse width is 15.2 ns, and the wavelength is 1064 nm. The experimental results show that all the damaging scenes are fiber entry faces. Damaging patterns can be classified as three types: pit damage, fusion damage and sputtering damage. Pit damage occurs most frequently. Scaffolding defects come into being pits when the laser irradiation is lower. Fusion damage is related to the laser energy, but sputtering damage occurs frequently when the laser energy or power density is very high (>10 7W/cm2~109W/cm2, ns pulse). The damage photos illustrate that fiber end damage is mainly due to laser ablation and gasification. Impurities of fiber material or contaminant particles adhere to fiber end are stress-raisers, which absorbed enough laser energy, make local temperature rises up quickly, ulterior fusion or gasification, and finally strong tensile stress. When stress goes beyond the tensile strength of fused-silica, damage occurs. The main damage mechanisms appear to be thermal effect and plasma ionization. The origin for the decline of laser induced-damage to fibers threshold appears to be extrinsic defect. The damage criterion and damage threshold test method are presented. The zero probability damage threshold is calculated by linear fitting, that is 58.6J/cm2. The damage process of fiber end faces could be divided into six steps. The origin for the decline of laser induced-damage to fibers threshold appears to be extrinsic defects which are closely related to the end-face quality.

  12. Deletion of GPR40 Impairs Glucose-Induced Insulin Secretion In Vivo in Mice Without Affecting Intracellular Fuel Metabolism in Islets

    SciTech Connect

    Alquier, Thierry; Peyot, Marie-Line; Latour, M. G.; Kebede, Melkam; Sorensen, Christina M.; Gesta, Stephane; Kahn, C. R.; Smith, Richard D.; Jetton, Thomas L.; Metz, Thomas O.; Prentki, Marc; Poitout, Vincent J.

    2009-11-01

    The G protein-coupled receptor GPR40 mediates fatty-acid potentiation of glucose-stimulated insulin secretion, but its contribution to insulin secretion in vivo and mechanisms of action remain uncertain. This study was aimed to ascertain whether GPR40 controls insulin secretion in vivo and modulates intracellular fuel metabolism in islets. We observed that glucose- and arginine-stimulated insulin secretion, assessed by hyperglycemic clamps, was decreased by approximately 60% in GPR40 knock-out (KO) fasted and fed mice, without changes in insulin sensitivity assessed by hyperinsulinemic-euglycemic clamps. Glucose and palmitate metabolism were not affected by GPR40 deletion. Lipid profiling revealed a similar increase in triglyceride and decrease in lysophosphatidylethanolamine species in WT and KO islets in response to palmitate. These results demonstrate that GPR40 regulates insulin secretion in vivo not only in response to fatty acids but also to glucose and arginine, without altering intracellular fuel metabolism.

  13. Islet cell development.

    PubMed

    Rojas, Anabel; Khoo, Adrian; Tejedo, Juan R; Bedoya, Francisco J; Soria, Bernat; Martín, Franz

    2010-01-01

    Over the last years, there has been great success in driving stem cells toward insulin-expressing cells. However, the protocols developed to date have some limitations, such as low reliability and low insulin production. The most successful protocols used for generation of insulin-producing cells from stem cells mimic in vitro pancreatic organogenesis by directing the stem cells through stages that resemble several pancreatic developmental stages. Islet cell fate is coordinated by a complex network of inductive signals and regulatory transcription factors that, in a combinatorial way, determine pancreatic organ specification, differentiation, growth, and lineage. Together, these signals and factors direct the progression from multipotent progenitor cells to mature pancreatic cells. Later in development and adult life, several of these factors also contribute to maintain the differentiated phenotype of islet cells. A detailed understanding of the processes that operate in the pancreas during embryogenesis will help us to develop a suitable source of cells for diabetes therapy. In this chapter, we will discuss the main transcription factors involved in pancreas specification and beta-cell formation.

  14. Repair and misrepair of heavy-ion-induced chromosomal damage

    NASA Astrophysics Data System (ADS)

    Goodwin, E.; Blakely, E.; Ivery, G.; Tobias, C.

    The premature chromosome condensation (PCC) technique was used to investigate chromosomal damage, repair, and misrepair in the G1 phase of a human/hamster hybrid cell line that contains a single human chromosome. Plateau-phase cell cultures were exposed to either x-rays or a 425 MeV/u beam of neon ions near the Bragg peak where the LET is 183 keV/μm. An in situ hybridization technique coupled to fluorescent staining of PCC spreads confirmed the linearity of the dose response for initial chromatin breakage in the human chromosome to high doses (1600 cGy x-ray or 1062 cGy Ne). On Giemsa-stained slides, initial chromatin breakage in the total genome and the rejoining kinetics of these breaks were determined. As a measure of chromosomal misrepair, ring PCC aberrations were also scored. Ne ions were about 1.5 x more effective per unit dose compared to x-rays at producing the initially measured chromatin breakage. 90% of the x-ray-induced breaks rejoined in cells incubated at 37°C after exposure. In contrast, only 50% of Ne-ion-induced breaks rejoined. In the irradiated G1 cells, ring PCC aberrations increased with time apparently by first order kinetics after either x-ray or Ne exposures. However, far fewer rings formed in Ne-irradiated cells after a dose giving a comparable initial number of chromatin breaks. Following x-ray exposures, the yield of rings formed after long repair times (6 to 9 hrs) fit a quadratic dose-response curve. These results indicate quantitative and qualitative differences in the chromosomal lesions induced by low- and high-LET radiations.

  15. Paternal high-fat diet consumption induces common changes in the transcriptomes of retroperitoneal adipose and pancreatic islet tissues in female rat offspring.

    PubMed

    Ng, Sheau-Fang; Lin, Ruby C Y; Maloney, Christopher A; Youngson, Neil A; Owens, Julie A; Morris, Margaret J

    2014-04-01

    We previously showed that paternal high-fat diet (HFD) consumption programs β-cell dysfunction in female rat offspring, together with transcriptome alterations in islets. Here we investigated the retroperitoneal white adipose tissue (RpWAT) transcriptome using gene and pathway enrichment and pathway analysis to determine whether commonly affected network topologies exist between these two metabolically related tissues. In RpWAT, 5108 genes were differentially expressed due to a paternal HFD; the top 5 significantly enriched networks identified by pathway analysis in offspring of HFD fathers compared with those of fathers fed control diet were: mitochondrial and cellular response to stress, telomerase signaling, cell death and survival, cell cycle, cellular growth and proliferation, and cancer. A total of 187 adipose olfactory receptor genes were down-regulated. Interrogation against the islet transcriptome identified specific gene networks and pathways, including olfactory receptor genes that were similarly affected in both tissues (411 common genes, P<0.05). In particular, we highlight a common molecular network, cell cycle and cancer, with the same hub gene, Myc, suggesting early onset developmental changes that persist, shared responses to programmed systemic factors, or crosstalk between tissues. Thus, paternal HFD consumption triggers unique gene signatures, consistent with premature aging and chronic degenerative disorders, in both RpWAT and pancreatic islets of daughters.

  16. Zinc protects HepG2 cells against the oxidative damage and DNA damage induced by ochratoxin A

    SciTech Connect

    Zheng, Juanjuan; Zhang, Yu; Xu, Wentao; Luo, YunBo; Hao, Junran; Shen, Xiao Li; Yang, Xuan; Li, Xiaohong; Huang, Kunlun

    2013-04-15

    Oxidative stress and DNA damage are the most studied mechanisms by which ochratoxin A (OTA) induces its toxic effects, which include nephrotoxicity, hepatotoxicity, immunotoxicity and genotoxicity. Zinc, which is an essential trace element, is considered a potential antioxidant. The aim of this paper was to investigate whether zinc supplement could inhibit OTA-induced oxidative damage and DNA damage in HepG2 cells and the mechanism of inhibition. The results indicated that that exposure of OTA decreased the intracellular zinc concentration; zinc supplement significantly reduced the OTA-induced production of reactive oxygen species (ROS) and decrease in superoxide dismutase (SOD) activity but did not affect the OTA-induced decrease in the mitochondrial membrane potential (Δψ{sub m}). Meanwhile, the addition of the zinc chelator N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) strongly aggravated the OTA-induced oxidative damage. This study also demonstrated that zinc helped to maintain the integrity of DNA through the reduction of OTA-induced DNA strand breaks, 8-hydroxy-2′-deoxyguanosine (8-OHdG) formation and DNA hypomethylation. OTA increased the mRNA expression of metallothionein1-A (MT1A), metallothionein2-A (MT2A) and Cu/Zn superoxide dismutase (SOD1). Zinc supplement further enhanced the mRNA expression of MT1A and MT2A, but it had no effect on the mRNA expression of SOD1 and catalase (CAT). Zinc was for the first time proven to reduce the cytotoxicity of OTA through inhibiting the oxidative damage and DNA damage, and regulating the expression of zinc-associated genes. Thus, the addition of zinc can potentially be used to reduce the OTA toxicity of contaminated feeds. - Highlights: ► OTA decreased the intracellular zinc concentration. ► OTA induced the formation of 8-OHdG in HepG2 cells. ► It was testified for the first time that OTA induced DNA hypomethylation. ► Zinc protects against the oxidative damage and DNA damage induced by

  17. Radiation-Induced Damage to Nucleic Acid Constituents

    NASA Astrophysics Data System (ADS)

    Kim, Heasook

    The objective of this research was to identify the primary free radical species produced by ionizing radiation in DNA. The ultimate goal would be to use these data obtained from model compounds to analyze radiation-induced damage in DNA itself. The different single crystals were studied in detail. The first was the sodium salt of guanosine-3 ^':5^' -cyclic monophosphate (cyclic GMP). The results of studies on crystals irradiated at 4.2^ circK distinguished two species. One of these species exhibited a non-exchangeable proton coupling that was characterized by ENDOR spectroscopy and shown to be sigma proton. The spin density on C8 was deduced from the ENDOR hyperfine coupling tensor and found to be 0.15. The second species also exhibited a non-exchangeable sigma proton coupling and a beta proton coupling. The spin densities on C8 and N9 were deduced from ENDOR measurements to be 0.09 and 0.36. The former is attributed to the oxidation product and the latter to the primary reduction product. These products are respectively the guanine cation and anion. The second single crystal studied was a sodium salt of 2^'-deoxyguanosine -5^'-monophosphate tetrahydrate. The ESR and ENDOR spectra obtained from this crystal after x-irradiation at 4.2^circK were complex and the paramagnetic species were tentatively identified as ionic species. The third DNA model compound studied was thymidine. Single crystal of thymidine were irradiated at 1.6^ circK and at 4.2^circ K. The lower temperature preserved a more primitive stage of the radiation damage process. ENDOR measurements distinguished three paramagnetic species. The most interesting component of the paramagnetic absorption in crystals irradiated at 1.6^circK is attributed to trapped electron. These electrons are stabilized by the electrostatic fields generated by hydroxy dipoles. The hyperfine couplings between the trapped electron and the proton of these polar groups were deduced from ENDOR measurements. The ESR and ENDOR

  18. The Pancreatic Islet Regulome Browser

    PubMed Central

    Mularoni, Loris; Ramos-Rodríguez, Mireia; Pasquali, Lorenzo

    2017-01-01

    The pancreatic islet is a highly specialized tissue embedded in the exocrine pancreas whose primary function is that of controlling glucose homeostasis. Thus, understanding the transcriptional control of islet-cell may help to puzzle out the pathogenesis of glucose metabolism disorders. Integrative computational analyses of transcriptomic and epigenomic data allows predicting genomic coordinates of putative regulatory elements across the genome and, decipher tissue-specific functions of the non-coding genome. We herein present the Islet Regulome Browser, a tool that allows fast access and exploration of pancreatic islet epigenomic and transcriptomic data produced by different labs worldwide. The Islet Regulome Browser is now accessible on the internet or may be installed locally. It allows uploading custom tracks as well as providing interactive access to a wealth of information including Genome-Wide Association Studies (GWAS) variants, different classes of regulatory elements, together with enhancer clusters, stretch-enhancers and transcription factor binding sites in pancreatic progenitors and adult human pancreatic islets. Integration and visualization of such data may allow a deeper understanding of the regulatory networks driving tissue-specific transcription and guide the identification of regulatory variants. We believe that such tool will facilitate the access to pancreatic islet public genomic datasets providing a major boost to functional genomics studies in glucose metabolism related traits including diabetes. PMID:28261261

  19. The effects of pre-exercise vibration stimulation on the exercise-induced muscle damage

    PubMed Central

    Kim, Ji-Yun; Kang, Da-Haeng; Lee, Joon-Hee; O, Se-Min; Jeon, Jae-Keun

    2017-01-01

    [Purpose] To investigate the effects of pre-induced muscle damage vibration stimulation on the pressure-pain threshold and muscle-fatigue-related metabolites of exercise-induced muscle damage. [Subjects and Methods] Thirty healthy, adult male subjects were randomly assigned to the pre-induced muscle damage vibration stimulation group, post-induced muscle damage vibration stimulation group, or control group (n=10 per group). To investigate the effects of pre-induced muscle damage vibration stimulation, changes in the pressure-pain threshold (lb), creatine kinase level (U/L), and lactate dehydrogenase level (U/L) were measured and analyzed at baseline and at 24 hours, 48 hours, and 72 hours after exercise. [Results] The pressure-pain thresholds and concentrations of creatine kinase and lactate dehydrogenase varied significantly in each group and during each measurement period. There were interactions between the measurement periods and groups, and results of the post-hoc test showed that the pre-induced muscle damage vibration stimulation group had the highest efficacy among the groups. [Conclusion] Pre-induced muscle damage vibration stimulation is more effective than post-induced muscle damage vibration stimulation for preventing muscle damage. PMID:28210056

  20. Deficiency in the nuclear factor E2-related factor 2 renders pancreatic β-cells vulnerable to arsenic-induced cell damage

    SciTech Connect

    Yang, Bei; Fu, Jingqi; Zheng, Hongzhi; Xue, Peng; Yarborough, Kathy; Woods, Courtney G.; Hou, Yongyong; Zhang, Qiang; Andersen, Melvin E.; Pi, Jingbo

    2012-11-01

    Chronic human exposure to inorganic arsenic (iAs), a potent environmental oxidative stressor, is associated with increased prevalence of type 2 diabetes, where impairment of pancreatic β-cell function is a key pathogenic factor. Nuclear factor E2-related factor 2 (Nrf2) is a central transcription factor regulating cellular adaptive response to oxidative stress. However, persistent activation of Nrf2 in response to chronic oxidative stress, including inorganic arsenite (iAs{sup 3+}) exposure, blunts glucose-triggered reactive oxygen species (ROS) signaling and impairs glucose-stimulated insulin secretion (GSIS). In the current study, we found that MIN6 pancreatic β-cells with stable knockdown of Nrf2 (Nrf2-KD) by lentiviral shRNA and pancreatic islets isolated from Nrf2-knockout (Nrf2−/−) mice exhibited reduced expression of several antioxidant and detoxification enzymes in response to acute iAs{sup 3+} exposure. As a result, Nrf2-KD MIN6 cells and Nrf2−/− islets were more susceptible to iAs{sup 3+} and monomethylarsonous acid (MMA{sup 3+})-induced cell damage, as measured by decreased cell viability, augmented apoptosis and morphological change. Pretreatment of MIN6 cells with Nrf2 activator tert-butylhydroquinone protected the cells from iAs{sup 3+}-induced cell damage in an Nrf2-dependent fashion. In contrast, antioxidant N‐acetyl cysteine protected Nrf2-KD MIN6 cells against acute cytotoxicity of iAs{sup 3+}. The present study demonstrates that Nrf2-mediated antioxidant response is critical in the pancreatic β-cell defense mechanism against acute cytotoxicity by arsenic. The findings here, combined with our previous results on the inhibitory effect of antioxidants on ROS signaling and GSIS, suggest that Nrf2 plays paradoxical roles in pancreatic β-cell dysfunction induced by environmental arsenic exposure. -- Highlights: ► Lack of Nrf2 reduced expression of antioxidant genes induced by iAs{sup 3+} in β-cells. ► Deficiency of Nrf2 in

  1. Methylphenidate and Amphetamine Do Not Induce Cytogenetic Damage in Lymphocytes of Children with ADHD

    ERIC Educational Resources Information Center

    Witt, Kristine L.; Shelby, Michael D.; Itchon-Ramos, Nilda; Faircloth, Melissa; Kissling, Grace E.; Chrisman, Allan K.; Ravi, Hima; Murli, Hemalatha; Mattison, Donald R.; Kollins, Scott H.

    2008-01-01

    The inducement of chromosomal damage in lymphocytes among children with attention deficit hyperactivity disorder receiving treatment with methylphenidate- or amphetamine-based drugs is investigated. Findings did not reveal significant increases in cytogenetic damage related to the treatment. The risk for cytogenetic damage posed by such products…

  2. Methylphenidate and Amphetamine Do Not Induce Cytogenetic Damage in Lymphocytes of Children with ADHD

    ERIC Educational Resources Information Center

    Witt, Kristine L.; Shelby, Michael D.; Itchon-Ramos, Nilda; Faircloth, Melissa; Kissling, Grace E.; Chrisman, Allan K.; Ravi, Hima; Murli, Hemalatha; Mattison, Donald R.; Kollins, Scott H.

    2008-01-01

    The inducement of chromosomal damage in lymphocytes among children with attention deficit hyperactivity disorder receiving treatment with methylphenidate- or amphetamine-based drugs is investigated. Findings did not reveal significant increases in cytogenetic damage related to the treatment. The risk for cytogenetic damage posed by such products…

  3. Calculation of complex DNA damage induced by ions

    NASA Astrophysics Data System (ADS)

    Surdutovich, Eugene; Gallagher, David C.; Solov'yov, Andrey V.

    2011-11-01

    This paper is devoted to the analysis of the complex damage of DNA irradiated by ions. The assessment of complex damage is important because cells in which it occurs are less likely to survive because the DNA repair mechanisms may not be sufficiently effective. We study the flux of secondary electrons through the surface of nucleosomes and calculate the radial dose and the distribution of clustered damage around the ion's path. The calculated radial dose distribution is compared to simulations. The radial distribution of the complex damage is found to be different from that of the dose. A comparison with experiments may solve the question of what is more lethal for the cell, damage complexity or absorbed energy. We suggest a way to calculate the probability of cell death based on the complexity of the damage. This work is done within the framework of the phenomenon-based multiscale approach to radiation damage by ions.

  4. Mitochondrial DNA damage induced autophagy, cell death, and disease.

    PubMed

    Van Houten, Bennett; Hunter, Senyene E; Meyer, Joel N

    2016-01-01

    Mammalian mitochondria contain multiple small genomes. While these organelles have efficient base excision removal of oxidative DNA lesions and alkylation damage, many DNA repair systems that work on nuclear DNA damage are not active in mitochondria. What is the fate of DNA damage in the mitochondria that cannot be repaired or that overwhelms the repair system? Some forms of mitochondrial DNA damage can apparently trigger mitochondrial DNA destruction, either via direct degradation or through specific forms of autophagy, such as mitophagy. However, accumulation of certain types of mitochondrial damage, in the absence of DNA ligase III (Lig3) or exonuclease G (EXOG), can directly trigger cell death. This review examines the cellular effects of persistent damage to mitochondrial genomes and discusses the very different cell fates that occur in response to different kinds of damage.

  5. Subsurface defects of fused silica optics and laser induced damage at 351 nm.

    PubMed

    Hongjie, Liu; Jin, Huang; Fengrui, Wang; Xinda, Zhou; Xin, Ye; Xiaoyan, Zhou; Laixi, Sun; Xiaodong, Jiang; Zhan, Sui; Wanguo, Zheng

    2013-05-20

    Many kinds of subsurface defects are always present together in the subsurface of fused silica optics. It is imperfect that only one kind of defects is isolated to investigate its impact on laser damage. Therefore it is necessary to investigate the impact of subsurface defects on laser induced damage of fused silica optics with a comprehensive vision. In this work, we choose the fused silica samples manufactured by different vendors to characterize subsurface defects and measure laser induced damage. Contamination defects, subsurface damage (SSD), optical-thermal absorption and hardness of fused silica surface are characterized with time-of-flight secondary ion mass spectrometry (TOF-SIMS), fluorescence microscopy, photo-thermal common-path interferometer and fully automatic micro-hardness tester respectively. Laser induced damage threshold and damage density are measured by 351 nm nanosecond pulse laser. The correlations existing between defects and laser induced damage are analyzed. The results show that Cerium element and SSD both have a good correlation with laser-induced damage thresholds and damage density. Research results evaluate process technology of fused silica optics in China at present. Furthermore, the results can provide technique support for improving laser induced damage performance of fused silica.

  6. Intracellular glutathione production, but not protein glycation, underlies the protective effects of captopril against 2-deoxy-D-ribose-induced β-cell damage.

    PubMed

    Koh, Gwanpyo; Yang, Eun-Jin; Kim, Ji Young; Hyun, Jonghoon; Yoo, Soyeon; Lee, Sang Ah

    2015-10-01

    Our previous study reported that both oxidative stress and protein glycation were the principal mechanisms underlying 2‑deoxy‑D‑ribose (dRib)‑induced pancreatic β‑cell damage. The aim of the present study was to investigate the effects of captopril on dRib‑induced damage in pancreatic β‑cells, as well as to determine the mechanisms underlying these effects. Treatment with dRib increased the levels of cytotoxicity, apoptosis, and intracellular reactive oxygen species in Syrian hamster insulinoma HIT‑T15 cells; however, pretreatment with captopril significantly inhibited the effects of dRib. The intracellular levels of reduced and oxidized glutathione were depleted following treatment with dRib; however, these levels were restored following HIT‑T15 cell treatment with captopril. In rat islets, dRib stimulation suppressed the mRNA expression levels of insulin, and pancreatic and duodenal homeobox 1, as well as insulin content; however, these effects were dose‑dependently reversed by treatment with captopril. Treatment with buthionine sulfoximine, an inhibitor of intracellular glutathione biosynthesis, inhibited the protective effects of captopril on dRib‑mediated glutathione depletion and cytotoxicity in HIT‑T15 cells. Following incubation with albumin, dRib increased the formation of dicarbonyl and advanced glycation end products. Treatment with captopril did not inhibit the dRib‑induced increase in production of dicarbonyl and advanced glycation end products. In conclusion, treatment with captopril reversed dRib‑induced oxidative damage and suppression of insulin expression in β‑cells. The mechanism underlying the protective effects of captopril may involve increased intracellular glutathione production, rather than protein glycation.

  7. Assessment of islet quality following international shipping of more than 10,000 km.

    PubMed

    Ikemoto, Tetsuya; Matsumoto, Shinichi; Itoh, Takeshi; Noguchi, Hirofumi; Tamura, Yoshiko; Jackson, Andrew M; Shimoda, Masayuki; Naziruddin, Bashoo; Onaca, Nicholas; Yasunami, Yohichi; Levy, Marlon F

    2010-01-01

    Islet transplantation is an attractive therapy for type 1 diabetes, although some issues remain. One of them is the severe donor shortage in some countries. In this study, we investigated the possibility of international islet shipping beyond 10,000 km to supply islets to countries with donor shortages. Human islets were isolated from six cadaver donors and cultured until shipment. Islets were packed in either gas-permeable bags or in non-gas-permeable bags and shipped from Baylor Research Institute (Dallas, TX, USA) to Fukuoka University (Fukuoka, Japan). Pre- and postshipment islet number, purity, viability, and stimulation index (by glucose stimulation test) were assessed. Shipped 1,500 IE islets were transplanted into streptozotocin-induced diabetic nude mice for in vivo assay. The distance of our shipment was 11,148.4 km, and the mean duration of the shipments was 48.2 ± 8.2 h. The islet number recovery rate (postshipment/preshipment) was significantly higher in gas-permeable bags (56.4 ± 10.1% vs. 20.5 ± 20.6%, p < 0.01). Islet purity was significantly reduced during shipment in non-gas-permeable bags (from 47.7 ± 18.6% to 40.2 ± 28.2 in gas-permeable bags vs. from 50.4 ± 6.4% to 25.9 ± 15.6% in non-gas-permeable bags, p < 0.05). Islet viability and stimulation index did not change significantly between pre- and postshipping, in either gas-permeable bags or in non-gas-permeable bags. One of three diabetic nude mice (33.3%) converted to normoglycemia. It is feasible to ship human islet cells internationally in gas-permeable bags. This strategy would promote basic and preclinical research for countries with donor shortages, even though the research centers are remote (over 10,000 km from the islet isolation center).

  8. Accumulation of Intrahepatic Islet Amyloid in a Nonhuman Primate Transplant Model

    PubMed Central

    Liu, Chengyang; Koeberlein, Brigitte; Feldman, Michael D.; Mueller, Rebecca; Wang, Zhonglin; Li, Yanjing; Lane, Kristin; Hoyt, Clifford C.; Tomaszewski, John E.; Naji, Ali

    2012-01-01

    Islet amyloid is hypothesized to play a role in nonimmunologic transplanted islet graft loss. We performed a quantitative histologic analysis of liver biopsies from intrahepatic islet grafts transplanted in streptozotocin-induced diabetic cynomolgus macaques. Seven animals treated with antithymocyte globulin (ATG) and rapamycin or ATG and rituximab experienced islet graft rejection with lymphocytic infiltrates present on islet graft biopsies. Except for one case involving the oldest and largest donor where amyloid was present on initial biopsy 1 month after transplant, none of the six other cases with rejection contained amyloid, including one case biopsied serially to 25 months. In contrast, four out of six animals treated with ATG and rituximab and rapamycin had no evidence of rejection at the time of biopsy (two animals that discontinued rapamycin had mild periislet lymphocytes), and all four cases followed more than 4 months demonstrated amyloid deposition at subsequent time points. Amyloid severity increased with time after transplant (r = 0.68; P < 0.05) and with decreasing islet β-cell area (r = −0.68; P < 0.05). In two islet recipients with no evidence of rejection and still normoglycemic and insulin independent at the first detection of amyloid, β-cell secretory capacity declined over time coincident with increasing amyloid severity and decreasing β-cell area, with both animals eventually becoming hyperglycemic and insulin dependent. Transplanted islet amyloid also developed in autologous islets placed sc. These results indicate that in cynomolgus macaques, transplanted islets may accumulate amyloid over time associated with subsequent decline in β-cell mass and function and support the development of intrahepatic islet amyloid as a potential mechanism for nonimmunologic islet graft loss. PMID:22355065

  9. Accumulation of intrahepatic islet amyloid in a nonhuman primate transplant model.

    PubMed

    Liu, Chengyang; Koeberlein, Brigitte; Feldman, Michael D; Mueller, Rebecca; Wang, Zhonglin; Li, Yanjing; Lane, Kristin; Hoyt, Clifford C; Tomaszewski, John E; Naji, Ali; Rickels, Michael R

    2012-04-01

    Islet amyloid is hypothesized to play a role in nonimmunologic transplanted islet graft loss. We performed a quantitative histologic analysis of liver biopsies from intrahepatic islet grafts transplanted in streptozotocin-induced diabetic cynomolgus macaques. Seven animals treated with antithymocyte globulin (ATG) and rapamycin or ATG and rituximab experienced islet graft rejection with lymphocytic infiltrates present on islet graft biopsies. Except for one case involving the oldest and largest donor where amyloid was present on initial biopsy 1 month after transplant, none of the six other cases with rejection contained amyloid, including one case biopsied serially to 25 months. In contrast, four out of six animals treated with ATG and rituximab and rapamycin had no evidence of rejection at the time of biopsy (two animals that discontinued rapamycin had mild periislet lymphocytes), and all four cases followed more than 4 months demonstrated amyloid deposition at subsequent time points. Amyloid severity increased with time after transplant (r = 0.68; P < 0.05) and with decreasing islet β-cell area (r = -0.68; P < 0.05). In two islet recipients with no evidence of rejection and still normoglycemic and insulin independent at the first detection of amyloid, β-cell secretory capacity declined over time coincident with increasing amyloid severity and decreasing β-cell area, with both animals eventually becoming hyperglycemic and insulin dependent. Transplanted islet amyloid also developed in autologous islets placed sc. These results indicate that in cynomolgus macaques, transplanted islets may accumulate amyloid over time associated with subsequent decline in β-cell mass and function and support the development of intrahepatic islet amyloid as a potential mechanism for nonimmunologic islet graft loss.

  10. Non-Problematic Risks from Low-Dose Radiation-Induced DNA Damage Clusters

    PubMed Central

    Hayes, Daniel P.

    2008-01-01

    Radiation-induced DNA damage clusters have been proposed and are usually considered to pose the threat of serious biological damage. This has been attributed to DNA repair debilitation or cessation arising from the complexity of cluster damage. It will be shown here, contrary to both previous suggestions and perceived wisdom, that radiation induced damage clusters contribute to non-problematic risks in the low-dose, low-LET regime. The very complexity of cluster damage which inhibits and/or compromises DNA repair will ultimately be responsible for the elimination and/or diminution of precancer-ous and cancerous cells. PMID:18648573

  11. An 'alpha-beta' of pancreatic islet microribonucleotides.

    PubMed

    Dalgaard, Louise Torp; Eliasson, Lena

    2017-01-22

    MicroRNAs (miRNAs) are cellular, short, non-coding ribonucleotides acting as endogenous posttranscriptional repressors following incorporation in the RNA-induced silencing complex. Despite being chemically and mechanistically very similar, miRNAs exert a multitude of different cellular effects by acting on mRNA species, whose gene-products partake in a wide array of processes. Here, the aim was to review the knowledge of miRNA expression and action in the islet of Langerhans. We have focused on: 1) physiological consequences of islet or beta cell specific inhibition of miRNA processing, 2) mechanisms regulating processing of miRNAs in islet cells, 3) presence and function of miRNAs in alpha versus beta cells - the two main cell types of islets, and 4) miRNA mediators of beta cell decompensation. It is clear that miRNAs regulate pancreatic islet development, maturation, and function in vivo. Moreover, processing of miRNAs appears to be altered by obesity, diabetes, and aging. A number of miRNAs (such as miR-7, miR-21, miR-29, miR-34a, miR-212/miR-132, miR-184, miR-200 and miR-375) are involved in mediating beta cell dysfunction and/or compensation induced by hyperglycemia, oxidative stress, cytotoxic cytokines, and in rodent models of fetal metabolic programming prediabetes and overt diabetes. Studies of human type 2 diabetic islets underline that these miRNA families could have important roles also in human type 2 diabetes. Furthermore, there is a genuine gap of knowledge regarding miRNA expression and function in pancreatic alpha cells. Progress in this area would be enhanced by improved in vitro alpha cell models and better tools for islet cell sorting.

  12. Examination of naturally occurring polyacetylenes and alpha-terthienyl for their ability to induce cytogenetic damage.

    PubMed

    MacRae, W D; Chan, G F; Wat, C K; Towers, G H; Lam, J

    1980-09-15

    alpha-Terthienyl and 5 polyacetylenes were examined for chromosome damaging activity using Syrian hamster cells. None of these naturally occurring compounds induced sister chromatid exchanges and neither alpha-terthienyl nor phenylheptatriyne induced chromosome aberrations.

  13. Engineering of microscale three-dimensional pancreatic islet models in vitro and their biomedical applications.

    PubMed

    Gao, Bin; Wang, Lin; Han, Shuang; Pingguan-Murphy, Belinda; Zhang, Xiaohui; Xu, Feng

    2016-08-01

    Diabetes now is the most common chronic disease in the world inducing heavy burden for the people's health. Based on this, diabetes research such as islet function has become a hot topic in medical institutes of the world. Today, in medical institutes, the conventional experiment platform in vitro is monolayer cell culture. However, with the development of micro- and nano-technologies, several microengineering methods have been developed to fabricate three-dimensional (3D) islet models in vitro which can better mimic the islet of pancreases in vivo. These in vitro islet models have shown better cell function than monolayer cells, indicating their great potential as better experimental platforms to elucidate islet behaviors under both physiological and pathological conditions, such as the molecular mechanisms of diabetes and clinical islet transplantation. In this review, we present the state-of-the-art advances in the microengineering methods for fabricating microscale islet models in vitro. We hope this will help researchers to better understand the progress in the engineering 3D islet models and their biomedical applications such as drug screening and islet transplantation.

  14. Effects of vitamins on chromium(VI)-induced damage

    SciTech Connect

    Sugiyama, Masayasu )

    1991-05-01

    The effects of vitamin E and vitamin B{sub 2} on DNA damage and cellular reduction of chromium (VI) were investigated using Chinese hamster V-79 cells. pretreatment with {alpha}-tocopherol succinate (vitamin E) resulted in a decrease of DNA single-strand breaks produced by Na{sub 2}CrO{sub 4}, while similar treatment with riboflavin (vitamin B{sub 2}) enhanced levels of DNA breaks. Electron spin resonance (ESR) studies showed that incubation of cells with Na{sub 2}CrO{sub 4} resulted in the formation of both chromium (V) and chromium (III) complexes, and cellular pretreatment with vitamin E reduced the level of the chromium (V) complex, whereas pretreatment with vitamin B{sub 2} enhanced the level of this intermediate. ESR studies demonstrated that a chromium (V) species was formed by the reaction of Na{sub 2}CrO{sub 4} with vitamin B{sub 2} and that vitamin B{sub 2} enhanced the formation of hydroxyl radicals during the reaction of Na{sub 2}CrO{sub 4} and hydrogen peroxide. These results indicate that vitamin E and vitamin B{sub 2} are capable of altering the biological effects of carcinogenic chromium (VI) compounds, possibly through their abilities to modify levels of chromium (V) in cells. The results also suggest that chromate-induced cytotoxicity may not be directly correlated with the genotoxic effects of this metal. The importance of the role of vitamins in chromate-induced toxicity is discussed.

  15. Feeding NOD mice with pig splenocytes induces transferable mechanisms that modulate cellular and humoral xenogeneic reactions against pig spleen or islet cells

    PubMed Central

    YOU, S; GOUIN, E; SAÏ, P

    2002-01-01

    We have reported previously that oral administration of pig cells to NOD mice modified xenogeneic cellular response against pig islet cells (PICs), and hypothesized that it may have induced active suppression. This preliminary report evaluated only the effect of feeding pig cells by ‘primary’ proliferation, i.e. when splenocytes from fed mice are confronted with pig cells in vitro. The present study also considered ‘secondary’ proliferation and cytokine production after feeding and subsequent in vivo graft of pig cells. Additionally, serum IgM and IgG isotypes were quantified by ELISA using pig target cells. Induction of active mechanism by feeding was hypothetical, which led us here to transfer splenocytes from mice fed pig spleen cells (PSC) and evaluate ‘primary’ (after transfer) and ‘secondary’ (after transfer and subsequent graft of pig cells) proliferations and cytokine secretions in recipient mice. We also determined whether the effects of feeding pig cells persisted after depression of suppressor mechanisms by cyclophosphamide. Mice fed with PSC displayed increased ‘primary’ splenocyte proliferation to PSC or PIC (P < 0·0001), while ‘secondary’ responses were decreased (P < 0·03) in those fed PSC and subsequently grafted with PSC. The increased ‘primary’ and decreased ‘secondary’ proliferations were reduced (P < 0·04) by pretreatment with cyclophosphamide. The IL-10/ and IL-4/IFNγ ratios produced in response to PSC increased (P < 0·04) in mice fed and grafted with PSC compared to those grafted only with PSC. IgM and IgG levels against pig cells were, respectively, increased (P < 0·04) and decreased (P < 0·04) in mice fed and grafted with PSC. IgG2a and IgG2b, but not IgG1, levels were lower (P < 0·01). These effects of feeding PSC on ‘secondary’ proliferation, cytokine and antibody productions, were not detected when mice were fed PSC only after graft with PSC. Transfer with splenocytes from mice fed PSC increased

  16. Physical analysis on laser-induced cerebral damage

    NASA Astrophysics Data System (ADS)

    Luo, Xiaosen; Liu, Jiangang; Tao, Chunkan; Lan, Xiufeng; Cao, Lingyan; Pan, Weimin; Shen, Zhonghua; Lu, Jian; Ni, Xiaowu

    2005-01-01

    Experimental investigation on cerebral damage of adult SD rats induced by 532nm CW laser was performed. Tissue heat conductive equation was set up based on two-layered structure model. Finite difference algorithm was utilized to numerically simulate the temperature distribution in the brain tissue. Allowing for tissue response to temperature variation, free boundary model was used to discuss tissue thermal coagulation formation in brain. Experimental observations show that thermal coagulation and necrosis can be caused due to laser light absorption. The result of the calculation shows that the process of the thermal coagulation of the given mode comprises two stages: fast and slow. At the first stage, necrosis domain grows fast. Then necrosis domain growth becomes slower because of the competition between the heat diffusion into the surrounding undamaged tissue and the heat dissipation caused by blood perfusion. At the center of coagulation area no neuron was observed and at the transitional zone few nervous cells were seen by microscope. The research can provide reference data for developing clinical therapy of some kind of encephalic diseases by using 532nm laser, and for making cerebral infarction models in animal experiment.

  17. SHI induced damage in electrical properties of silicon NPN BJTs

    NASA Astrophysics Data System (ADS)

    Kumar, M. Vinay; Kumar, Santhosh; Yashoda, T.; Krishnaveni, S.

    2016-05-01

    The investigation of radiation damage in Si microelectronic circuitry and devices are being carried out by various research groups globally. In particular the Si Bipolar junction transistors are very sensitive to high energetic radiation. In the present study, radiation response of NPN Bipolar junction transistor (2N3773) has been examined for 60 MeV B4+ ion. Key electrical properties like Gummel, dc current gain and capacitance - voltage (C-V) characteristics of 60 MeV B4+ ion irradiated transistor were studied before and after irradiation. Ion irradiation and subsequent electrical characterizations were performed at room temperature. Current voltage (I-V) measurements showed the increase in collector current for VBE ≤ 0.4 V as a function of fluence, which is due to B4+ ion induced surface leakage currents. Base current is observed to be more sensitive than collector current and gain appears to be degraded with ion fluence. Also, C-V measurements shows that both built in potential and doping concentration increased significantly after irradiation.

  18. Retinal Damage Induced by Internal Limiting Membrane Removal

    PubMed Central

    Gelman, Rachel; Stevenson, William; Prospero Ponce, Claudia; Agarwal, Daniel; Christoforidis, John Byron

    2015-01-01

    The internal limiting membrane (ILM), the basement membrane of the Müller cells, serves as the interface between the vitreous body and the retinal nerve fiber layer. It has a fundamental role in the development, structure, and function of the retina, although it also is a pathologic component in the various vitreoretinal disorders, most notably in macular holes. It was not until understanding of the evolution of idiopathic macular holes and the advent of idiopathic macular hole surgery that the idea of adjuvant ILM peeling in the treatment of tractional maculopathies was explored. Today intentional ILM peeling is a commonly applied surgical technique among vitreoretinal surgeons as it has been found to increase the rate of successful macular hole closure and improve surgical outcomes in other vitreoretinal diseases. Though ILM peeling has refined surgery for tractional maculopathies, like all surgical procedures it is not immune to perioperative risk. The essential role of the ILM to the integrity of the retina and risk of trauma to retinal tissue spurs suspicion with regard to its routine removal. Several authors have investigated the retinal damage induced by ILM peeling and these complications have been manifested across many different diagnostic studies. PMID:26425355

  19. Calculation of radiation damage induced by neutrons in compound materials

    NASA Astrophysics Data System (ADS)

    Lunéville, L.; Simeone, D.; Jouanne, C.

    2006-07-01

    Many years have been devoted to study the behaviour of solids submitted to impinging particles like ions or neutrons. The nuclear evaluations describe more and more accurately the various neutron-atom interactions. Anisotropic neutron-atom cross-sections are now available for many elements. Moreover, clear mathematical formalism now allows to calculate the number of displacements per atom in polyatomic targets in a realistic way using the binary collision approximation (BCA) framework. Even if these calculations do not take into account relaxation processes at the end of the displacement spike, they can be used to compare damages induced by different facilities like pressurized water reactors (PWR), fast breeder reactors (FBR), high temperature reactors (HTR) and fusion facilities like the European Spallation Source (ESS) and the International Fusion Material Irradiation Facility (IFMIF) on a defined material. In this paper, a formalism is presented to describe the neutron-atom cross-section and primary recoil spectra taking into account the anisotropy of nuclear reactions extracted from nuclear evaluations. Such a formalism permitted to compute displacement per atom production rate, primary and weighted recoil spectra within the BCA. The multigroup approximation has been used to calculate displacement per atom production rate and recoil spectra for a define nuclear reactor. All these informations are useful to compare recoil spectra and displacement per atom production rate produced by particle accelerator and nuclear reactor.

  20. Chemical modification of normal tissue damage induced by photodynamic therapy.

    PubMed Central

    Sigdestad, C. P.; Fingar, V. H.; Wieman, T. J.; Lindberg, R. D.

    1996-01-01

    One of the limitations of successful use of photodynamic therapy (PDT) employing porphyrins is the acute and long-term cutaneous photosensitivity. This paper describes results of experiments designed to test the effects of two radiation protective agents (WR-2721, 500 mg kg-1 or WR-3689, 700 mg kg-1) on murine skin damage induced by PDT. C3H mice were shaved and depilated three days prior to injection with the photosensitiser, Photofrin (5 or 10 mg kg-1). Twenty-four hours later, the mice were injected intraperitoneally with a protector 30 min prior to Argon dye laser (630 nm) exposure. The skin response was followed for two weeks post irradiation using an arbitrary response scale. A light dose response as well as a drug dose response was obtained. The results indicate that both protectors reduced the skin response to PDT, however WR-2721 was demonstrated to be the most effective. The effect of the protectors on vascular stasis after PDT was determined using a fluorescein dye exclusion assay. In mice treated with Photofrin (5 mg kg-1), and 630 nm light (180 J cm-2) pretreatment with either WR-2721 or WR-3689 resulted in significant protection of the vascular effects of PDT. These studies document the ability of the phosphorothioate class of radiation protective agents to reduce the effects of light on photosensitized skin. They do so in a drug dose-dependent fashion with maximum protection at the highest drug doses. PMID:8763855

  1. SHI induced damage in electrical properties of silicon NPN BJTs

    SciTech Connect

    Kumar, M. Vinay Krishnaveni, S.; Kumar, Santhosh; Yashoda, T.

    2016-05-23

    The investigation of radiation damage in Si microelectronic circuitry and devices are being carried out by various research groups globally. In particular the Si Bipolar junction transistors are very sensitive to high energetic radiation. In the present study, radiation response of NPN Bipolar junction transistor (2N3773) has been examined for 60 MeV B{sup 4+} ion. Key electrical properties like Gummel, dc current gain and capacitance – voltage (C-V) characteristics of 60 MeV B{sup 4+} ion irradiated transistor were studied before and after irradiation. Ion irradiation and subsequent electrical characterizations were performed at room temperature. Current voltage (I-V) measurements showed the increase in collector current for V{sub BE} ≤ 0.4 V as a function of fluence, which is due to B{sup 4+} ion induced surface leakage currents. Base current is observed to be more sensitive than collector current and gain appears to be degraded with ion fluence. Also, C-V measurements shows that both built in potential and doping concentration increased significantly after irradiation.

  2. DNA damage profiles induced by sunlight at different latitudes.

    PubMed

    Schuch, André Passaglia; Yagura, Teiti; Makita, Kazuo; Yamamoto, Hiromasa; Schuch, Nelson Jorge; Agnez-Lima, Lucymara Fassarella; MacMahon, Ricardo Monreal; Menck, Carlos Frederico Martins

    2012-04-01

    Despite growing knowledge on the biological effects of ultraviolet (UV) radiation on human health and ecosystems, it is still difficult to predict the negative impacts of the increasing incidence of solar UV radiation in a scenario of global warming and climate changes. Hence, the development and application of DNA-based biological sensors to monitor the solar UV radiation under different environmental conditions is of increasing importance. With a mind to rendering a molecular view-point of the genotoxic impact of sunlight, field experiments were undertaken with a DNA-dosimeter system in parallel with physical photometry of solar UVB/UVA radiation, at various latitudes in South America. On applying biochemical and immunological approaches based on specific DNA-repair enzymes and antibodies, for evaluating sunlight-induced DNA damage profiles, it became clear that the genotoxic potential of sunlight does indeed vary according to latitude. Notwithstanding, while induction of oxidized DNA bases is directly dependent on an increase in latitude, the generation of 6-4PPs is inversely so, whereby the latter can be regarded as a biomolecular marker of UVB incidence. This molecular DNA lesion-pattern largely reflects the relative incidence of UVA and UVB energy at any specific latitude. Hereby is demonstrated the applicability of this DNA-based biosensor for additional, continuous field experiments, as a means of registering variations in the genotoxic impact of solar UV radiation. © 2012 Wiley Periodicals, Inc.

  3. Radiation-induced chromosome damage in astronauts' lymphocytes.

    PubMed

    Testard, I; Ricoul, M; Hoffschir, F; Flury-Herard, A; Dutrillaux, B; Fedorenko, B; Gerasimenko, V; Sabatier, L

    1996-10-01

    The increased number of manned space missions has made it important to estimate the biological risks encountered by astronauts. As they are exposed to cosmic rays, especially ions with high linear energy transfer (LET), it is necessary to estimate the doses they receive. The most sensitive biological dosimetry used is based on the quantification of radiation-induced chromosome damage to human lymphocytes. After the space missions ANTARES (1992) and ALTAIR (1993), we performed cytogenetic analysis of blood samples from seven astronauts who had spent from 2 weeks to 6 months in space. After 2 or 3 weeks, the X-ray equivalent dose was found to be below the cytogenetic detection level of 20 mGy. After 6 months, the biological dose greatly varied among the astronauts, from 95 to 455 mGy equivalent dose. These doses are in the same range as those estimated by physical dosimetry (90 mGy absorbed dose and 180 mSv equivalent dose). Some blood cells exhibited the same cytogenetic pattern as the 'rogue cells' occasionally observed in controls, but with a higher frequency. We suggest that rogue cells might result from irradiation with high-LET particles of cosmic origin. However, the responsibility of such cells for the long-term effects of cosmic irradiation remains unknown and must be investigated.

  4. Novel DNA damage checkpoint in mitosis: Mitotic DNA damage induces re-replication without cell division in various cancer cells.

    PubMed

    Hyun, Sun-Yi; Rosen, Eliot M; Jang, Young-Joo

    2012-07-06

    DNA damage induces multiple checkpoint pathways to arrest cell cycle progression until damage is repaired. In our previous reports, when DNA damage occurred in prometaphase, cells were accumulated in 4 N-DNA G1 phase, and mitosis-specific kinases were inactivated in dependent on ATM/Chk1 after a short incubation for repair. We investigated whether or not mitotic DNA damage causes cells to skip-over late mitotic periods under prolonged incubation in a time-lapse study. 4 N-DNA-damaged cells re-replicated without cell division and accumulated in 8 N-DNA content, and the activities of apoptotic factors were increased. The inhibition of DNA replication reduced the 8 N-DNA cell population dramatically. Induction of replication without cell division was not observed upon depletion of Chk1 or ATM. Finally, mitotic DNA damage induces mitotic slippage and that cells enter G1 phase with 4 N-DNA content and then DNA replication is occurred to 8 N-DNA content before completion of mitosis in the ATM/Chk1-dependent manner, followed by caspase-dependent apoptosis during long-term repair.

  5. The Evaluation of Islet Purification Methods That Use Large Bottles to Create a Continuous Density Gradient

    PubMed Central

    Miyagi-Shiohira, Chika; Kobayashi, Naoya; Saitoh, Issei; Watanabe, Masami; Noguchi, Yasufumi; Matsushita, Masayuki; Noguchi, Hirofumi

    2017-01-01

    Islet purification is one of the most important steps of islet isolation for pancreatic islet transplantation. The most common method of islet purification is density gradient centrifugation using a COBE 2991 cell processor. However, this method can damage islets mechanically through its high shearing force. We recently reported that a new purification method using large plastic bottles effectively achieves a high yield of islets from the porcine pancreas. In the present study, we evaluated the methods of making a continuous density gradient. The gradient was produced with a gradient maker and two types of candy cane-shaped stainless steel pipes. One method was to use a “bent-tipped” stainless steel pipe and to load from a high-density solution to a low-density solution, uploading the stainless steel pipe. The other method was to use a regular stainless steel pipe and to load from a low-density solution to a high-density solution, leaving the stainless steel pipe in place. There were no significant differences between the two solutions in terms of the islet yield, rate of viability or purity, score, or the stimulation index after purification. Furthermore, there were no differences in the attainability or suitability of posttransplantation normoglycemia. Our study shows the equivalency of these two methods of islet purification. PMID:28174674

  6. Topical Application of Liposomal Antioxidants for Protection Against CEES Induced Skin Damage

    DTIC Science & Technology

    2008-06-01

    W81XWH-05-2-0034 TITLE: Topical Application of Liposomal Antioxidants for Protection Against CEES Induced Skin Damage PRINCIPAL...Topical Application of Liposomal Antioxidants for Protection Against CEES Induced Skin Damage 5b. GRANT NUMBER W81XWH-05-2-0034 5c. PROGRAM...effective prophylactic therapy against skin damage caused by an analog of mustard gas, 2-chloroethylethyl sulfide (CEES) using in vitro model systems

  7. Blood Flow After Exercise-Induced Muscle Damage

    PubMed Central

    Selkow, Noelle M.; Herman, Daniel C.; Liu, Zhenqi; Hertel, Jay; Hart, Joseph M.; Saliba, Susan A.

    2015-01-01

    Context: The most common modality used to address acute inflammation is cryotherapy. Whereas pain decreases with cryotherapy, evidence that changes occur in perfusion of skeletal muscle is limited. We do not know whether ice attenuates the increases in perfusion associated with acute inflammation. Objective: To examine the effects of repeated applications of ice bags on perfusion of the gastrocnemius muscle after an eccentric exercise protocol. Design: Controlled laboratory study. Setting: Laboratory. Patients or Other Participants: Eighteen healthy participants (3 men, 15 women; age = 22.2 ± 2.2 years, height = 166.0 ± 11.9 cm, mass = 69.4 ± 25.0 kg). Intervention(s): To induce eccentric muscle damage, participants performed 100 unilateral heel-lowering exercises off a step to the beat of a metronome. A randomized intervention (cryotherapy, sham, control) was applied to the exercised lower extremity immediately after the protocol and again at 10, 24, and 34 hours after the protocol. Main Outcome Measure(s): Baseline perfusion measurements (blood volume, blood flow, and blood flow velocity) were taken using contrast-enhanced ultrasound of the exercised leg. Perfusion was reassessed after the first intervention and 48 hours after the protocol as percentage change scores. Pain was measured with a visual analog scale at baseline and at 10, 24, 34, and 48 hours after the protocol. Separate repeated-measures analyses of variance were used to assess each dependent variable. Results: We found no interactions among interventions for microvascular perfusion. Blood volume and blood flow, however, increased in all conditions at 48 hours after exercise (P < .001), and blood flow velocity decreased postintervention from baseline (P = .041). We found a time-by-intervention interaction for pain (P = .009). Visual analog scale scores were lower for the cryotherapy group than for the control group at 34 and 48 hours after exercise. Conclusions: Whereas eccentric muscle damage

  8. Pancreatic islet blood flow and its measurement.

    PubMed

    Jansson, Leif; Barbu, Andreea; Bodin, Birgitta; Drott, Carl Johan; Espes, Daniel; Gao, Xiang; Grapensparr, Liza; Källskog, Örjan; Lau, Joey; Liljebäck, Hanna; Palm, Fredrik; Quach, My; Sandberg, Monica; Strömberg, Victoria; Ullsten, Sara; Carlsson, Per-Ola

    2016-05-01

    Pancreatic islets are richly vascularized, and islet blood vessels are uniquely adapted to maintain and support the internal milieu of the islets favoring normal endocrine function. Islet blood flow is normally very high compared with that to the exocrine pancreas and is autonomously regulated through complex interactions between the nervous system, metabolites from insulin secreting β-cells, endothelium-derived mediators, and hormones. The islet blood flow is normally coupled to the needs for insulin release and is usually disturbed during glucose intolerance and overt diabetes. The present review provides a brief background on islet vascular function and especially focuses on available techniques to measure islet blood perfusion. The gold standard for islet blood flow measurements in experimental animals is the microsphere technique, and its advantages and disadvantages will be discussed. In humans there are still no methods to measure islet blood flow selectively, but new developments in radiological techniques hold great hopes for the future.

  9. Pancreatic islet blood flow and its measurement

    PubMed Central

    Jansson, Leif; Barbu, Andreea; Bodin, Birgitta; Drott, Carl Johan; Espes, Daniel; Gao, Xiang; Grapensparr, Liza; Källskog, Örjan; Lau, Joey; Liljebäck, Hanna; Palm, Fredrik; Quach, My; Sandberg, Monica; Strömberg, Victoria; Ullsten, Sara; Carlsson, Per-Ola

    2016-01-01

    Pancreatic islets are richly vascularized, and islet blood vessels are uniquely adapted to maintain and support the internal milieu of the islets favoring normal endocrine function. Islet blood flow is normally very high compared with that to the exocrine pancreas and is autonomously regulated through complex interactions between the nervous system, metabolites from insulin secreting β-cells, endothelium-derived mediators, and hormones. The islet blood flow is normally coupled to the needs for insulin release and is usually disturbed during glucose intolerance and overt diabetes. The present review provides a brief background on islet vascular function and especially focuses on available techniques to measure islet blood perfusion. The gold standard for islet blood flow measurements in experimental animals is the microsphere technique, and its advantages and disadvantages will be discussed. In humans there are still no methods to measure islet blood flow selectively, but new developments in radiological techniques hold great hopes for the future. PMID:27124642

  10. Local opioid-sensitive afferent sensory neurones in the modulation of gastric damage induced by Paf.

    PubMed Central

    Esplugues, J. V.; Whittle, B. J.; Moncada, S.

    1989-01-01

    1. The role of local sensory neurones in modulating the extent of gastric mucosal damage induced by close-arterial infusion of platelet-activating factor (Paf 50 ng kg-1 min-1 for 10 min) has been investigated in the anaesthetized rat. 2. Local intra-arterial infusion of the neurotoxin, tetrodotoxin (TTX), substantially augmented the mucosal damage induced by Paf, as assessed by both macroscopic and histological techniques. 3. In rats pretreated with capsaicin 2 weeks prior to study, to induce a functional ablation of primary afferent neurones, gastric damage induced by Paf was significantly augmented. 4. Administration of morphine (0.75-3 mg kg-1 i.v.) or its peripherally acting quaternary analogue, N-methyl morphine (15 mg kg-1 i.v.), also significantly enhanced the gastric damage induced by Paf. 5. The potentiation by morphine of Paf-induced gastric damage was inhibited by administration of the opioid antagonists, naloxone (1 mg kg-1 i.v.) or the peripherally acting N-methyl nalorphine (3 mg kg-1 i.v.). 6. Administration of TTX or morphine alone, or pretreatment with capsaicin did not induce any detectable mucosal damage, suggesting that interference with local sensory neuronal activity itself does not directly induce mucosal disruption. 7. These results indicate that peripheral opiate-sensitive afferent sensory neurones play a physiological defensive role in the mucosa, attenuating the extent of gastric damage induced by Paf. PMID:2758231

  11. Cosmic ray induced permanent damage in MNOS EAROMs

    NASA Astrophysics Data System (ADS)

    Blandford, J. T., Jr.; Pickel, J. C.; Waskiewicz, A. E.

    1984-12-01

    Permanent damage to the memory cells in Metal Nitride Oxide Semiconductor (MNOS) Electrically Alterable Read Only Memories (EAROM) has been observed after exposure to a heavy ion beam from a cyclotron under high field (Erase/Write Mode) conditions. The probability of permanent damage depends on the system application.

  12. Cosmic ray induced permanent damage in MNOS EAROMs

    SciTech Connect

    Blandford, J.T.; Pickel, J.C.; Waskiewicz, A.E.

    1984-12-01

    Permanent damage to the memory cells in Metal Nitride Oxide Semiconductor (MNOS) Electrically Alterable Read Only Memories (EAROM) has been observed after exposure to a heavy ion beam from a cyclotron under high field (Erase/Write Mode) conditions. The probability, of permanent damage depends on the system application.

  13. Molecular responses of radiation-induced liver damage in rats.

    PubMed

    Cheng, Wei; Xiao, Lei; Ainiwaer, Aimudula; Wang, Yunlian; Wu, Ge; Mao, Rui; Yang, Ying; Bao, Yongxing

    2015-04-01

    The aim of the present study was to investigate the molecular responses involved in radiation‑induced liver damage (RILD). Sprague‑Dawley rats (6‑weeks‑old) were irradiated once at a dose of 20 Gy to the right upper quadrant of the abdomen. The rats were then sacrificed 3 days and 1, 2, 4, 8 and 12 weeks after irradiation and rats, which were not exposed to irradiation were used as controls. Weight measurements and blood was obtained from the rats and liver tissues were collected for histological and apoptotic analysis. Immunohistochemistry, reverse transcription quantitative polymerase chain reaction (RT‑qPCR) and western blot analysis were performed to measure the expression levels of mRNAs and proteins, respectively. The serum levels of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase were increased significantly in the RILD rats. Histological investigation revealed the proliferation of collagen and the formation of fibrotic tissue 12 weeks after irradiation. Apoptotic cells were observed predominantly 2 and 4 weeks after irradiation. The immunohistochemistry, RT‑qPCR and western blot analysis all revealed the same pattern of changes in the expression levels of the molecules assessed. The expression levels of transforming growth factor‑β1 (TGF‑β1), nuclear factor (NF)‑κB65, mothers against decapentaplegic homolog 3 (Smad3) and Smad7 and connective tissue growth factor were increased during the recovery period following irradiation up to 12 weeks. The expression levels of tumor necrosis factor‑α, Smad7 and Smad4 were only increased during the early phase (first 4 weeks) of recovery following irradiation. In the RILD rat model, the molecular responses indicated that the TGF‑β1/Smads and NF‑κB65 signaling pathways are involved in the mechanism of RILD recovery.

  14. DNA damage induced by red food dyes orally administered to pregnant and male mice.

    PubMed

    Tsuda, S; Murakami, M; Matsusaka, N; Kano, K; Taniguchi, K; Sasaki, Y F

    2001-05-01

    We determined the genotoxicity of synthetic red tar dyes currently used as food color additives in many countries, including JAPAN: For the preliminary assessment, we treated groups of 4 pregnant mice (gestational day 11) once orally at the limit dose (2000 mg/kg) of amaranth (food red No. 2), allura red (food red No. 40), or acid red (food red No. 106), and we sampled brain, lung, liver, kidney, glandular stomach, colon, urinary bladder, and embryo 3, 6, and 24 h after treatment. We used the comet (alkaline single cell gel electrophoresis) assay to measure DNA damage. The assay was positive in the colon 3 h after the administration of amaranth and allura red and weakly positive in the lung 6 h after the administration of amaranth. Acid red did not induce DNA damage in any sample at any sampling time. None of the dyes damaged DNA in other organs or the embryo. We then tested male mice with amaranth, allura red, and a related color additive, new coccine (food red No. 18). The 3 dyes induced DNA damage in the colon starting at 10 mg/kg. Twenty ml/kg of soaking liquid from commercial red ginger pickles, which contained 6.5 mg/10 ml of new coccine, induced DNA damage in colon, glandular stomach, and bladder. The potencies were compared to those of other rodent carcinogens. The rodent hepatocarcinogen p-dimethylaminoazobenzene induced colon DNA damage at 1 mg/kg, whereas it damaged liver DNA only at 500 mg/kg. Although 1 mg/kg of N-nitrosodimethylamine induced DNA damage in liver and bladder, it did not induce colon DNA damage. N-nitrosodiethylamine at 14 mg/kg did not induce DNA damage in any organs examined. Because the 3 azo additives we examined induced colon DNA damage at a very low dose, more extensive assessment of azo additives is warranted.

  15. Angiopoetin-2 Signals Do Not Mediate the Hypervascularization of Islets in Type 2 Diabetes

    PubMed Central

    Shah, Payal; Lueschen, Navina; Ardestani, Amin; Oberholzer, Jose; Olerud, Johan; Carlsson, Per-Ola; Maedler, Kathrin

    2016-01-01

    Aims Changes in the islet vasculature have been implicated in the regulation of β-cell survival and function during the progression to type 2 diabetes (T2D). Failure of the β-cell to compensate for the increased insulin demand in obesity eventually leads to diabetes; as a result of the complex interplay of genetic and environmental factors (e.g. ongoing inflammation within the islets) and impaired vascular function. The Angiopoietin/Tie (Ang/Tie) angiogenic system maintains vasculature and is closely related to organ inflammation and angiogenesis. In this study we aimed to identify whether the vessel area within the islets changes in diabetes and whether such changes would be triggered by the Tie-antagonist Ang-2. Methods Immunohistochemical and qPCR analyses to follow islet vascularization and Ang/Tie levels were performed in human pancreatic autopsies and isolated human and mouse islets. The effect of Ang-2 was assessed in β-cell-specific Ang-2 overexpressing mice during high fat diet (HFD) feeding. Results Islet vessel area was increased in autopsy pancreases from patients with T2D. The vessel markers Tie-1, Tie-2 and CD31 were upregulated in mouse islets upon HFD feeding from 8 to 24 weeks. Ang-2 was transiently upregulated in mouse islets at 8 weeks of HFD and under glucolipotoxic conditions (22.2 mM glucose/ 0.5 mM palmitate) in vitro in human and mouse islets, in contrast to its downregulation by cytokines (IL-1β, IFN-ɣ and TNF-α). Ang-1 on the other hand was oppositely regulated, with a significant loss under glucolipotoxic condition, a trend to reduce in islets from patients with T2D and an upregulation by cytokines. Modulation of such changes in Ang-2 by its overexpression or the inhibition of its receptor Tie-2 impaired β-cell function at basal conditions but protected islets from cytokine induced apoptosis. In vivo, β-cell-specific Ang-2 overexpression in mice induced hypervascularization under normal diet but contrastingly led to

  16. Angiopoetin-2 Signals Do Not Mediate the Hypervascularization of Islets in Type 2 Diabetes.

    PubMed

    Shah, Payal; Lueschen, Navina; Ardestani, Amin; Oberholzer, Jose; Olerud, Johan; Carlsson, Per-Ola; Maedler, Kathrin

    2016-01-01

    Changes in the islet vasculature have been implicated in the regulation of β-cell survival and function during the progression to type 2 diabetes (T2D). Failure of the β-cell to compensate for the increased insulin demand in obesity eventually leads to diabetes; as a result of the complex interplay of genetic and environmental factors (e.g. ongoing inflammation within the islets) and impaired vascular function. The Angiopoietin/Tie (Ang/Tie) angiogenic system maintains vasculature and is closely related to organ inflammation and angiogenesis. In this study we aimed to identify whether the vessel area within the islets changes in diabetes and whether such changes would be triggered by the Tie-antagonist Ang-2. Immunohistochemical and qPCR analyses to follow islet vascularization and Ang/Tie levels were performed in human pancreatic autopsies and isolated human and mouse islets. The effect of Ang-2 was assessed in β-cell-specific Ang-2 overexpressing mice during high fat diet (HFD) feeding. Islet vessel area was increased in autopsy pancreases from patients with T2D. The vessel markers Tie-1, Tie-2 and CD31 were upregulated in mouse islets upon HFD feeding from 8 to 24 weeks. Ang-2 was transiently upregulated in mouse islets at 8 weeks of HFD and under glucolipotoxic conditions (22.2 mM glucose/ 0.5 mM palmitate) in vitro in human and mouse islets, in contrast to its downregulation by cytokines (IL-1β, IFN-ɣ and TNF-α). Ang-1 on the other hand was oppositely regulated, with a significant loss under glucolipotoxic condition, a trend to reduce in islets from patients with T2D and an upregulation by cytokines. Modulation of such changes in Ang-2 by its overexpression or the inhibition of its receptor Tie-2 impaired β-cell function at basal conditions but protected islets from cytokine induced apoptosis. In vivo, β-cell-specific Ang-2 overexpression in mice induced hypervascularization under normal diet but contrastingly led to hypovascularized islets in response

  17. Raldh3 expression in diabetic islets reciprocally regulates secretion of insulin and glucagon from pancreatic islets.

    PubMed

    Shimamura, Mitsuru; Karasawa, Hiroshi; Sakakibara, Sachiko; Shinagawa, Akira

    2010-10-08

    We have previously reported that obesity-induced diabetes developed in high-fat diet (HFD)-fed BDF1 mice. This is caused by insufficient insulin response to an excess glucose load. In this study, we have shown that the enhanced expression of retinaldehyde dehydrogenase 3 (Raldh3) causes functional disorders of pancreatic islets in diabetic mouse models. In the pancreatic islets of HFD-induced diabetic BDF1 mice and spontaneously diabetic C57BL/KsJ(db/db) mice, gene expression analysis with oligonucleotide microarray revealed a significant increase in Raldh3 expression. Exposure to a culture medium containing a higher glucose concentration (25 mM) significantly increased Raldh3 expression in murine MIN6 and alphaTC1 clone 9 cells, which derived from the α and β-cells of pancreatic islets, respectively. Overexpression of Raldh3 reduced the insulin secretion in MIN6 cells, and surprisingly, increased the glucagon secretion in alphaTC1 clone 9 cells. Furthermore, the knockdown of Raldh3 expression with siRNA decreased the glucagon secretion in alphaTC1 clone 9 cells. Raldh3 catalyzes the conversion of 13-cis retinal to 13-cis retinoic acid and we revealed that 13-cis retinoic acid significantly reduces cell viability in MIN6 and alphaTC1 clone 9 cells, but not in cells of H4IIEC3, 3T3-L1, and COS-1 cell lines. These findings suggest that an increasing expression of Raldh3 deregulates the balanced mechanisms of insulin and glucagon secretion in the pancreatic islets and may induce β-cell dysfunction leading to the development of type 2 diabetes. Copyright © 2010 Elsevier Inc. All rights reserved.

  18. The effect of multiple wavelengths on Laser-induced damage in DKDP crystals

    SciTech Connect

    Carr, C W; Auerbach, J M

    2005-07-11

    Laser-induced damage is a key factor that constrains how optical materials are used in high-power laser systems. In this work the size and density of bulk laser-induced damage sites formed during frequency tripling in a DKDP crystal are studied. The characteristics of the damage sites formed during tripling, where 1053-nm, 526-nm, and 351-nm light is simultaneously present, are compared to damage sites formed by 351-nm light alone. The fluence of each wavelength is calculated as a function of depth with a full 4D(x,y,z,t) frequency conversion code and compared to measured damage density and size distributions. The density of damage is found be predominantly governed by 351-nm light with some lesser, though non-negligible contribution from 526-nm light. The morphology of the damage sites, however, is seen to be relatively insensitive to wavelength and depend only on total fluence of all wavelengths present.

  19. Impact of organic contamination on the laser-induced damage in vacuum

    NASA Astrophysics Data System (ADS)

    Ling, Xiulan; Zhao, Yuanan; Li, Dawei; Li, Shuhong; zhou, Ming; Shao, Jianda; Fan, Zhengxiu

    2009-08-01

    The impact of two organic contaminations on the damage characteristics of anti-reflector (AR) at 1064 nm is investigated. Contamination experiments were made with toluene and acetone in liquid phase on the surface of AR coatings. Chemical and morphological characterization methods were used to identify and understand the damage process. The possible damage process is analyzed and discussed. It is found that toluene decreases laser-induced damage threshold and acetone seems to be benign and has little influence on laser-induced damage threshold due to its quickly spreading into the coating. Adsorption and droplet micro-lensing effect mechanism are the main cause of enhanced laser-induced damage of toluene.

  20. Unraveling pancreatic islet biology by quantitative proteomics

    SciTech Connect

    Zhou, Jianying; Dann, Geoffrey P.; Liew, Chong W.; Smith, Richard D.; Kulkarni, Rohit N.; Qian, Weijun

    2011-08-01

    The pancreatic islets of Langerhans play a critical role in maintaining blood glucose homeostasis by secreting insulin and several other important peptide hormones. Impaired insulin secretion due to islet dysfunction is linked to the pathogenesis underlying both Type 1 and Type 2 diabetes. Over the past 5 years, emerging proteomic technologies have been applied to dissect the signaling pathways that regulate islet functions and gain an understanding of the mechanisms of islet dysfunction relevant to diabetes. Herein, we briefly review some of the recent quantitative proteomic studies involving pancreatic islets geared towards gaining a better understanding of islet biology relevant to metabolic diseases.

  1. Vitamin D3 supplementation increases insulin level by regulating altered IP3 and AMPA receptor expression in the pancreatic islets of streptozotocin-induced diabetic rat.

    PubMed

    Jayanarayanan, Sadanandan; Anju, Thoppil R; Smijin, Soman; Paulose, Cheramadathikudiyil Skaria

    2015-10-01

    Pancreatic islets, particularly insulin-secreting β cells, share common characteristics with neurons. Glutamate is one of the major excitatory neurotransmitter in the brain and pancreas, and its action is mediated through glutamate receptors. In the present work, we analysed the role of vitamin D3 in the modulation of AMPA receptor subunit and their functional role in insulin release. Radio receptor binding study in diabetic rats showed a significant increase in AMPA receptor density. Insulin AMPA colabelling study showed an altered AMPA GluR2 and GluR4 subunit expression in the pancreatic beta cells. We also found lowered IP3 content and decreased IP3 receptor in pancreas of diabetic rats. The alterations in AMPA and IP3 receptor resulted in reduced cytosolic calcium level concentration, which further blocks Ca(2+)-mediated insulin release. Vitamin D3 supplementation restored the alteration in vitamin D receptor expression, AMPA receptor density and AMPA and IP3 receptor expression in the pancreatic islets that helps to restore the calcium-mediated insulin secretion. Our study reveals the antidiabetic property of vitamin D3 that is suggested to have therapeutic role through regulating glutamatergic function in diabetic rats. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. DNA damage-induced cell death: from specific DNA lesions to the DNA damage response and apoptosis.

    PubMed

    Roos, Wynand P; Kaina, Bernd

    2013-05-28

    DNA damaging agents are potent inducers of cell death triggered by apoptosis. Since these agents induce a plethora of different DNA lesions, it is firstly important to identify the specific lesions responsible for initiating apoptosis before the apoptotic executing pathways can be elucidated. Here, we describe specific DNA lesions that have been identified as apoptosis triggers, their repair and the signaling provoked by them. We discuss methylating agents such as temozolomide, ionizing radiation and cisplatin, all of them are important in cancer therapy. We show that the potentially lethal events for the cell are O(6)-methylguanine adducts that are converted by mismatch repair into DNA double-strand breaks (DSBs), non-repaired N-methylpurines and abasic sites as well as bulky adducts that block DNA replication leading to DSBs that are also directly induced following ionizing radiation. Transcriptional inhibition may also contribute to apoptosis. Cells are equipped with sensors that detect DNA damage and relay the signal via kinases to executors, who on their turn evoke a process that inhibits cell cycle progression and provokes DNA repair or, if this fails, activate the receptor and/or mitochondrial apoptotic cascade. The main DNA damage recognition factors MRN and the PI3 kinases ATM, ATR and DNA-PK, which phosphorylate a multitude of proteins and thus induce the DNA damage response (DDR), will be discussed as well as the downstream players p53, NF-κB, Akt and survivin. We review data and models describing the signaling from DNA damage to the apoptosis executing machinery and discuss the complex interplay between cell survival and death. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Helium vs. Proton Induced Displacement Damage in Electronic Materials

    NASA Technical Reports Server (NTRS)

    Ringo, Sawnese; Barghouty, A. F.

    2010-01-01

    In this project, the specific effects of displacement damage due to the passage of protons and helium nuclei on some typical electronic materials will be evaluated and contrasted. As the electronic material absorbs the energetic proton and helium mome