BACKGROUND Autoimmunity has emerged as a probable disease modifier in patients with clinically diagnosed type 2 diabetes mellitus(T2DM),that is,patients who have insulin resistance,obesity,and other cardiovascular ris...BACKGROUND Autoimmunity has emerged as a probable disease modifier in patients with clinically diagnosed type 2 diabetes mellitus(T2DM),that is,patients who have insulin resistance,obesity,and other cardiovascular risk factors,suggesting that the presence of glutamic acid decarboxylase(anti-GAD65),islet antigen 2(anti-IA2),and zinc transporter 8(anti-Zn8T)antibodies could have deleterious effects on beta cell function,causing failure and earlier requirement for insulin treatment.AIM To evaluate anti-GAD65,anti-IA2 and anti-Zn8T as predictors of early insulin requirement in adolescents with a clinical diagnosis of T2DM.METHODS This was a case–control study in patients with clinically diagnosed with T2DM(68 cases and 64 controls with and without early insulin dependence respectively),male and female,aged 12–18 years.Somatometry,blood pressure,glucose,insulin,C-peptide,glycated hemoglobin A1c,and lipid profiles were assessed.ELISA was used to measure anti-GAD65,anti-IA2,and anti-Zn8T antibodies.Descriptive statistics,Pearson'sχ2 test,Student's t test,and logistic regression was performed.P<0.05 was considered statistically significant.RESULTS There were 132 patients(53.8%female),with a mean age was 15.9±1.3 years,and there was a disease evolution time of 4.49±0.88 years.The presence of anti-GAD65,anti-IA2,and anti-Zn8T positivity was found in 29.5%,18.2%,and 15.9%,respectively.Dividing the groups by early or no insulin dependence showed that the group with insulin had a higher frequency of antibody positivity:anti-GAD65 odds ratio(OR):2.42(1.112–5.303,P=0.026);anti-IA2:OR:1.55(0.859–2.818,P=0.105);and anti-Zn8T:OR:7.32(2.039–26.279,P=0.002).CONCLUSION Anti-GAD65 positivity was high in our study.Anti-GAD65 and anti-Zn8T positivity showed a significantly depleted beta cell reserve phenotype,leading to an increased risk of early insulin dependence.展开更多
If only at a small scale,islet transplantation has successfully addressed what ought to be the primary endpoint of any cell therapy:the functional replenishment of damaged tissue in patients.After years of less-thanop...If only at a small scale,islet transplantation has successfully addressed what ought to be the primary endpoint of any cell therapy:the functional replenishment of damaged tissue in patients.After years of less-thanoptimal approaches to immunosuppression,recent advances consistently yield long-term graft survival rates comparable to those of whole pancreas transplantation.Limited organ availability is the main hurdle that stands in the way of the widespread clinical utilization of this pioneering intervention.Progress in stem cell research over the past decade,coupled with our decades-long experience with islet transplantation,is shaping the future of cell therapies for the treatment of diabetes.Here we review the most promising avenues of research aimed at generating an inexhaustible supply of insulin-producing cells for islet regeneration,including the differentiation of pluripotent and multipotent stem cells of embryonic and adult origin along the beta cell lineage and the direct reprogramming of non-endocrine tissues into insulin-producing cells.展开更多
Type 1 diabetes is caused by insulin deficiency due to the loss of beta cells in the islets of Langerhans.In severe cases,islet transplantation into the portal vein is performed.However,due to the loss of transplanted...Type 1 diabetes is caused by insulin deficiency due to the loss of beta cells in the islets of Langerhans.In severe cases,islet transplantation into the portal vein is performed.However,due to the loss of transplanted islets and the failure of islet function,the 5-year insulin independence rate of these patients is<50%.In this study,we developed a long-term,insulin-secreting,3 Dbioprinted construct implanted subcutaneously with the aim of preventing islet loss.The bioprinted construct was fabricated by the multi-layer bioprinting of beta-cell(mouse insulinoma-6:MIN-6)-encapsulated alginate bioink and poly(caprolactone)biodegradable polymer.A glucose response assay revealed that the bioprinted constructs proliferated and released insulin normally during the 4-week in vitro period.Bioprinted MIN-6 generated clusters with a diameter of 100-200μm,similar to the original pancreatic islets in the construct.In an in vivo study using type 1 diabetes mice,animals implanted with bioprinted constructs showed three times higher insulin secretion and controlled glucose levels at 8 weeks after implantation.Because the implanted,bioprinted constructs had a positive effect on insulin secretion in the experimental animals,the survival rate of the implanted group(75%)was three times higher than that of the non-implanted group(25%).The results suggest that the proposed,3 D-bioprinted,subcutaneous construct can be a better alternative to portal vein islet transplantation.展开更多
Background: Catalase deficiency (acatalasemia) is sensitive to alloxan, and the administration to acatalasemic mice develops hyperglycemia under mild conditions. However, the mechanism is still poorly understood. Meth...Background: Catalase deficiency (acatalasemia) is sensitive to alloxan, and the administration to acatalasemic mice develops hyperglycemia under mild conditions. However, the mechanism is still poorly understood. Methods: Alloxan was used to induce the oxidative stress and intraperitoneally administered to acatalasemic and normal mice. The blood samples of these mice after 1, 3, 5 and 7 days were examined. The pancreatic islets 7 days after alloxan administration were isolated, and the insulin released under 3 mM and 20 mM glucose was examined. Results: After alloxan administration, increase of oxidative markers in blood and pancreatic apoptosis in acatalasemic mice were observed immediately. Insulin in blood was lowered after 3 days, and the insulin in acatalasemic mice was lower than that in normal mice. Hyperglycemia in the acatalasemic mice was observed after 3 days. The pancreatic islets after 7 days were isolated. A reduction of the insulin released from the islets under glucose stimulation was observed. The stimulation indexes of the normal and acatalasemic mice were 1.4 ± 0.6 and 0.7 ± 0.3, respectively. Conclusions: Alloxan induced a deterioration of glucose-dependent insulin secretion ability from the islets, and the deterioration mostly contributed to hyperglycemia, rather than apoptosis.展开更多
Chronic pancreatitis is best described as a relentless, continuous inflammatory destruction of the pancreas parenchyma, characterized by irreversible destruction of the exocrine tissues, fibrosis, and at the late stag...Chronic pancreatitis is best described as a relentless, continuous inflammatory destruction of the pancreas parenchyma, characterized by irreversible destruction of the exocrine tissues, fibrosis, and at the late stage, the destruction of endocrine cells. Current therapies for chronic pancreatitis patients focus on pain relief by medical and minimally invasive endoscopic treatment as well as surgical management with resection of diseased parenchyma and drainage of obstructed ducts. Radical treatment of chronic pancreatitis has been successful with total pancreatictomy and islet autotransplantation (TP-IAT) that may prevent maladaptive intractable pain pathways and also avoid pancreatogenic diabetes in the well-selected patient. Distinct loss of pancreatic islet cells occurs in about 30%-50% of patients during the progression of chronic pancreatitis when severe fibrosis develops at the late stage of the disease. Profound β cell apoptosis induced by stresses encountered during islet isolation and transplantation further compromises β cell survival and function after TP-IAT. The molecular mechanisms that lead to β cell dysfunction in chronic pancreatitis remain largely undelineated. In this review, we summarize factors that may contribute β cell apoptosis during the disease progress and after TP-IAT and discuss potential interventional approaches that may prevent islet cell death during these processes. Such information is critical to the development of therapeutic protocols that can preserve the viability and function of β cell in patients with chronic pancreatitis.展开更多
Background: Diabetes and diabetes-related complications are major causes of morbidity and mortality in the United States. Depressive symptoms and perceived stress have been identified as possible risk factors for beta...Background: Diabetes and diabetes-related complications are major causes of morbidity and mortality in the United States. Depressive symptoms and perceived stress have been identified as possible risk factors for beta cell dysfunction and diabetes. The purpose of this study was to assess associations between depression symptoms and perceived stress with beta cell function between African and Haitian Americans with and without type 2 diabetes. Participants and Methods: Informed consent and data were available for 462 participants (231 African Americans and 231 Haitian Americans) for this cross-sectional study. A demographic questionnaire developed by the Primary Investigator was used to collect information regarding age, gender, smoking, and ethnicity. Diabetes status was determined by self-report and confirmed by fasting blood glucose. Anthropometrics (weight, and height and waist circumference) and vital signs (blood pressure) were taken. Blood samples were drawn after 8 10 hours over-night fasting to measure lipid panel, fasting plasma glucose and serum insulin concentrations. The homeostatic model assessment, version 2 (HOMA2) computer model was used to calculate beta cell function. Depression was assessed using the Beck Depression Inventory-II (BDI-II) and stress levels were assessed using the Perceived Stress Scale (PSS). Results: Moderate to severe depressive symptoms were more likely for persons with diabetes (p = 0.030). There were no differences in perceived stress between ethnicity and diabetes status (p = 0.283). General linear models for participants with and without type 2 diabetes using beta cell function as the dependent variable showed no association with depressive symptoms and perceived stress;however, Haitian Americans had significantly lower beta cell function than African Americans both with and without diabetes and adjusting for age, gender, waist circumference and smoking. Further research is needed to compare these risk factors in other race/ethnic groups.展开更多
Diabetes mellitus,characterized by chronic hyperglycemia due to insulin deficiency or resistance,poses a significant global health burden.Central to its pathogenesis is the dysfunction or loss of pancreatic beta cells...Diabetes mellitus,characterized by chronic hyperglycemia due to insulin deficiency or resistance,poses a significant global health burden.Central to its pathogenesis is the dysfunction or loss of pancreatic beta cells,which are res-ponsible for insulin production.Recent advances in beta-cell regeneration research offer promising strategies for diabetes treatment,aiming to restore endogenous insulin production and achieve glycemic control.This review explores the physiological basis of beta-cell function,recent scientific advan-cements,and the challenges in translating these findings into clinical applications.It highlights key developments in stem cell therapy,gene editing technologies,and the identification of novel regenerative molecules.Despite the potential,the field faces hurdles such as ensuring the safety and long-term efficacy of regen-erative therapies,ethical concerns around stem cell use,and the complexity of beta-cell differentiation and integration.The review highlights the importance of interdisciplinary collaboration,increased funding,the need for patient-centered approaches and the integration of new treatments into comprehensive care strategies to overcome these challenges.Through continued research and collab-oration,beta-cell regeneration holds the potential to revolutionize diabetes care,turning a chronic condition into a manageable or even curable disease.展开更多
The association between chronic HCV infection and type 2 diabetes mellitus(T2DM)has been established;however,there is limited research onβ-cell function particularly in the pre-diabetic population.Here,we evaluated i...The association between chronic HCV infection and type 2 diabetes mellitus(T2DM)has been established;however,there is limited research onβ-cell function particularly in the pre-diabetic population.Here,we evaluated indices ofβ-cell function and insulin sensitivity across the spectrum from normal glucose tolerance to T2DMin individuals with and without chronic hepatitis C(CHC),and the effects of antiviral treatments on these variables.A total of 153 noncirrhotic,non-fibrotic CHC patients with a BMI<25 were enrolled in the study.Among them,119 were successfully treated with either direct acting antiviral(DAA)drugs or pegylated interferon/ribavirin(IFN/RBV)anti-HCV therapy.Fasting state-and oral glucose tolerance test(OGTT)-derived indexes were used to evaluateβ-cell function and insulin sensitivity.Among all subjects,19(13%)had T2DM and 21%exhibited pre-diabetes including 8%isolated impaired fasting glucose(IFG)and 13%combined IFG and impaired glucose tolerance(IGT).Early and total insulin secretion adjusted for the degree of insulin resistance were decreased in pre-diabetic CHC patients compared to HCVuninfected individuals.Viral eradication through DAA or IFN/RBV therapy demonstrated positive impacts on insulin sensitivity andβ-cell function in CHC patients who achieved sustained virologic response(SVR),regardless of fasting or OGTT state.These findings emphasize the role of HCV in the development ofβ-cell dysfunction,while also suggesting that viral eradication can improve insulin secretion,reverse insulin resistance,and ameliorate glycemic control.These results have important implications for managing pre-diabetic CHC patients and could prevent diabetes-related clinical manifestations and complications.展开更多
Background Type 2 diabetes is a chronic disease characterized by a progressive loss of beta cell functions. However, the evaluation of beta cell functions is either expensive or inconvenient for clinical practice. We ...Background Type 2 diabetes is a chronic disease characterized by a progressive loss of beta cell functions. However, the evaluation of beta cell functions is either expensive or inconvenient for clinical practice. We aimed to elucidate the association between the changes of insulin responsiveness and the fasting plasma glucose （FPG） during the development of diabetes. Methods A total of 1192 Chinese individuals with normal blood glucose or hyperglycemia were enrolled for the analysis. The early insulinogenic index （△I30/△G30）, the area under the curve of insulin （AUC-Ⅰ）, and homeostasis model assessment were applied to evaluate the early phase secretion, total insulin secretion, and insulin resistance respectively. Polynomial regression analysis was performed to estimate the fluctuation of beta cell functions. Results The △I30/△G30 decreased much more rapidly than the AUC-Ⅰ accompanying with the elevation of FPG. At the FPG of 110 mg/dl （a pre-diabetic stage）, the AI30/AG30 lost 50% of its maximum while the AUC-Ⅰ was still at a compensated normal level. The AUC-Ⅰ exhibited abnormal and decreased gradually at the FPG of from 130 mg/dl to higher （overt diabetes）, while the △I30/△G30 almost remained at 25% of its maximum value. When hyperglycemia continuously existed at 〉 180 mg/dl, both the AI30/AG30 and AUC-Ⅰ were totally lost. Conclusion The increased fasting plasma glucose reflects progressive decompensation of beta cell functions, and could be used to guide the strategy of clinical treatments.展开更多
AIM To investigate factors causing diabetes recurrence after sleeve gastrectomy(SG)and duodenal-jejunal bypass(DJB).METHODS SG and DJB were performed on rats with diabetes induced by high-fat diet(HFD)and streptozotoc...AIM To investigate factors causing diabetes recurrence after sleeve gastrectomy(SG)and duodenal-jejunal bypass(DJB).METHODS SG and DJB were performed on rats with diabetes induced by high-fat diet(HFD)and streptozotocin(STZ).HFD was used to induce diabetes recurrence at 4 wk postoperatively.Body weight,oral glucose tolerance test,homeostatic model assessment of insulin resistance(HOMA-IR),insulin signaling[IR,insulin receptor substrate(IRS 1,IRS2,phosphatidylinositol3-kinase and AKT in liver and skeletal muscle],oral glucose stimulated insulin secretion,beta-cell morphology(mass,apoptosis and insulin secretion),glucagon-like peptide(GLP)-1,PYY and ghrelin were compared among SG rats with common low-fat diet(SG-LFD),SG with HFD(SG-HFD),DJB rats with LFD(DJB-LFD),DJB with HFD(DJB-HFD)and shamoperation with LFD(Sham)at targeted postoperative times.RESULTS SG and DJB resulted in significant improvement in glucose tolerance,lower HOMA-IR,up-regulated hepatic and muscular insulin signaling,higher levels of oral glucose-stimulated insulin secretion,bigger betacell mass,higher immunofluorescence intensity of insulin,fewer transferase-mediated d UTP-biotin 3’nick end-labeling(TUNEL)-positive beta cells and higher postprandial GLP-1 and PYY levels than in the Sham group.The improvement in glucose tolerance was reversed at 12 wk postoperatively.Compared with the SG-LFD and DJB-LFD groups,the SG-HFD and DJB-HFD groups showed higher HOMA-IR,down-regulated hepatic and muscular insulin signaling,and more TUNEL-positive beta cells.No significant difference was detected between HFD and LFD groups for body weight,glucose-stimulated insulin secretion,betacell mass,immunofluorescence intensity of insulin,and postprandial GLP-1 and PYY levels.Fasting serum ghrelin decreased in SG groups,and there was no difference between HFD-SG and LFD-SG groups.CONCLUSION HFD reverses the improvement in glucose homeostasis after SG and DJB.Diabetes recurrence may correlate with re-impaired insulin sensitivity,but not with alterations of beta-cell function and body weight.展开更多
Background A 65-kD mdrl （multi-drug resistance protein 1, P-glycoprotein）-Iike protein has been suggested to be the regulatory protein to the chloride channel protein 3 （CIC-3） mediating insulin granules acidifica...Background A 65-kD mdrl （multi-drug resistance protein 1, P-glycoprotein）-Iike protein has been suggested to be the regulatory protein to the chloride channel protein 3 （CIC-3） mediating insulin granules acidification and release in mouse pancreatic beta cells. But the protein has not been deeply investigated. In this study, we identified existence of the 65-kda protein in rat islets and preliminarily explored its biological functions. Methods Total RNAs of rat kidneys served as positive controls, and pancreas, islets and INS-1 cells were extracted for reverse-transcript PCR （RT-PCR）, respectively. The cDNAs were run with specific primers selected from the mRNA of abcblb encoding P-glycoprotein. All PCR products were visualized in agarose gel electrophoresis and sequenced. Homogenates of rat islets and INS-1 cells were applied to SDS-PAGE. P-glycoprotein was detected by a specific monoclonal antibody, C219. Biphasic insulin release was measured in static incubations of rat islets with radioimmunology assay. Results Compared with positive control, expression of the P-glycoprotein mRNA segments were detected in the islets, INS-1 cells and pancreas. Sequence analysis confirmed that the PCR products were matched with mRNA of P-glycoprotein. A 65-kda protein was recognized by the antibody in the islets homogenate but not in that of INS-1 cells in Western-blotting. Instead, the homogenate of INS-1 cells contained a 160-kda protein recognized by the antibody. Insulin secretion of rat islets were stimulated by high glucose （16.7mmol/L）, and showed biphasic curve during 60-minute incubation. After co-incubation with cyclosporine A （CsA）, specific inhibitor to P-glycoprotein, the second phase of insulin secretion was reduced significantly while the first phase was not influenced. Conclusions The 65-kda protein expressed in rat islets is most likely a mini-P-glycoprotein. It may play a key role regulating biphasic insulin release.展开更多
Background Abnormal insulin secretion of pancreatic beta cells is now regarded as the more primary defect than the insulin function in the etiology of type 2 diabetes.Previous studies found impaired mitochondrial func...Background Abnormal insulin secretion of pancreatic beta cells is now regarded as the more primary defect than the insulin function in the etiology of type 2 diabetes.Previous studies found impaired mitochondrial function and impaired Ca2＋ influx in beta cells in diabetic patients and animal models,suggesting a role for these processes in proper insulin secretion.The aim of this study was to investigate the detailed relationship of mitochondrial function,Ca2＋ influx,and defective insulin secretion.Methods We investigated mitochondrial function and morphology in pancreatic beta cell of diabetic KK-Ay mice and C57BL/6J mice.Two types of Ca2＋ channel activities,L-type and store-operated Ca2＋ （SOC）,were evaluated using whole-cell patch-clamp recording.The glucose induced Ca2＋ influx was measured by a non-invasive micro-test technique （NMT）.Results Mitochondria in KK-Ay mice pancreatic beta cells were swollen with disordered cristae,and mitochondrial function decreased compared with C57BL/6J mice.Ca2＋ channel activity was increased and glucose induced Ca2＋ influx was impaired,but could be recovered by genipin.Conclusion Defective mitochondrial function in diabetic mice pancreatic beta cells is a key cause of abnormal insulin secretion by altering Ca2＋ influx,but not via Ca2＋ channel activity.展开更多
Objective： To examine the protective effect of ecdysterone （ECR） against beta-amyloid peptide fragment25-35 （Aβ25-35）-induced PC12 cells cytotoxicity, and to further explore its mechanism. Methods： Experimental...Objective： To examine the protective effect of ecdysterone （ECR） against beta-amyloid peptide fragment25-35 （Aβ25-35）-induced PC12 cells cytotoxicity, and to further explore its mechanism. Methods： Experimental PC12 cells were divided into the Aβ group （treated by Aβ25-35 100μmol/L）, the blank group （untreated）, the positive control group （treated by Vit E 100 μmol/L after induction） and the ECR treated groups （treated by ECR with different concentrations of 1, 50 and 100 μmol/L）. The damaged and survival condition of PC12 cells in various groups was monitored by lactate dehydrogenase （LDH） release and MTT assay. The content of malondialdehyde （MDA） was measured by fluorometric assay to indicate the lipid peroxidation. And the antioxidant enzymes activities in PC12 cells, including superoxide dismutases（SOD）, catalase （CAT） and glutathione peroxidase（GSH-Px）, were detected respectively. Results： After PC12 cells were treated with Aβ25-35 （100 μmol/L） for 24 hrs, they revealed a great decrease in MTT absorbance and activity of antioxidant enzymes, including SOD, CAT and GSH-Px as well as a significant increase of LDH activity and MDA content in PC12 cells （P〈0.01）. When the cells was pretreated with 1-100 μmol/L ECR for 24 hrs before Aβ25-35 treatment, the above-mentioned cytotoxic effect of Aβ25-35 could be significantly attenuated dose-dependently, for ECR 50 μmol/L, P〈0.05 and for ECR 100 μmol/L, P〈0.01. Moreover, ECR also showed significant inhibition on the Aβ25-35 induced decrease of SOD and GSH-Px activity, but not on that of CAT. Conclusion： ECR could protect PC12 cells from cytotoxicity of Aβ25-35, and the protective mechanism might be related to the increase of SOD and GSH-Px activities and the decrease of MDA resulting from the ECR-pretreatment.展开更多
BACKGROUND: Pancreatic stellate cells (PSCs) play a major role in promoting pancreatic fibrosis. Transforming growth factor beta 1 (TGF-beta 1) is a critical mediator of this process. This study aimed to determine the...BACKGROUND: Pancreatic stellate cells (PSCs) play a major role in promoting pancreatic fibrosis. Transforming growth factor beta 1 (TGF-beta 1) is a critical mediator of this process. This study aimed to determine the expression of the Smad3 and Smad7 genes in the process of PSC activation, and explore the mechanisms of chronic pancreatitis. METHODS: The expressions of Smad3 and Smad7 in PSCs before and after TGF-beta 1 treatment were detected by reverse transcription-polymerase chain reaction and Western blotting analysis. Smad3 expression was detected in PSCs after treatment with 5 ng/ml of TGF-beta 1 for 24 hours. RESULTS: Smad7 expression was decreased in TGF-beta 1 -activated PSCs (P<0.05) in a dose-dependent manner. When TGF-beta 1 concentration reached 10 ng/ml, the expression of p-Smad3, Smad3, and Smad7 was inhibited (P<0.05). CONCLUSIONS: TGF-beta 1 promotes the expression of Smad3 and inhibits the expression of Smad7 during the activation of PSCs. In contrast, high-dose TGF-beta 1 downregulates the expression of Smad3 in completely activated PSCs.展开更多
Objective: To investigate the antioxidant, anti-a-glucosidase and pancreatic b-cell protective potential of Ensete superbum(E. superbum) seeds.Methods: A variety of in vitro assays including radical scavenging, reduci...Objective: To investigate the antioxidant, anti-a-glucosidase and pancreatic b-cell protective potential of Ensete superbum(E. superbum) seeds.Methods: A variety of in vitro assays including radical scavenging, reducing power potential, phenolic content determination, a-glucosidase assay and pancreatic b-cell(1.4E7 cells) viability were employed for assessing the effect of methanolic extract of E. superbum seeds.Results: The radical scavenging and reducing power effects comparable with the standard rutin were obtained while the enzyme inhibitory activity of the extract was 68-fold better than the standard antidiabetic drug, acarbose. The seed extract of E. superbum was packed-full of polyphenols with mean percentage gallic acid equivalent value of(38.2 ± 1.8)(n = 3). The protection of pancreatic cells from massive onslaught of hydrogen peroxide was far superior to that obtained for rutin.Conclusions: The reputed antidiabetic therapeutic uses of the seeds extract of E. superbum may be justified on the basis of inhibition of carbohydrate enzymes, antioxidant effects and pancreatic b-cell protection.展开更多
AIM：To identify the pathological role of amyloid beta（Aβ） deposition in retinal degeneration,and explore Aβ deposition on the retinal pigment epithelium cells（RPE） layer and the associated structural and functi...AIM：To identify the pathological role of amyloid beta（Aβ） deposition in retinal degeneration,and explore Aβ deposition on the retinal pigment epithelium cells（RPE） layer and the associated structural and functional changes in Alzheimer＇s disease transgenic mice.METHODS：RPE changes in the eyes of APPswe/PS1 transgenic and none transgenic（NTG） mice over 20 months old were examined.Histological changes were investigated via hematoxylin and eosin（H＆E） staining and transmission electron microscopy（TEM） examination,whereas the expression of amyloid precursor protein（APP）,Aβ,Zonula occludens-1（ZO-1） and Ionized calcium binding adaptor molecule-1（IBA-1） were investigated using immunohistochemistry and immunofluorescence techniques.All of the obtained results were quantitatively and statistically analyzed.RESULTS：In aged transgenic mice,an APP-positive immunoreaction and Aβ deposition were detected on the RPE layer but were undetectable in NTG mice.The RPE demonstrated some vacuole changes,shortened basal infoldings and basal deposition in histopathological examination and TEM tests,wherein irregular shapes were indicated by ZO-1 disorganization through fluorescence.Furthermore,IBA-1 positive cells were observed to have accumulated and infiltrated into the RPE layer and localized beneath the RPE/Bruch＇s membrane（Br M） complex,which was accompanied by an increase in BrM thickness in aged transgenic mice in comparison to NTG mice.The IBA-1 positive cells were found to be co-stained with Aβ deposition on the RPE flat mounts.CONCLUSION：The observed Aβ deposition in the RPE layer may cause RPE dysfunction,which is associated with microglia cells infiltration into the retina of aged transgenic mice,suggesting that Aβ deposition probably plays a significant role in RPE-related degenerative disease.展开更多
One of our previous studies showed that Yizhijiannao Granule,a compound Chinese medicine, effectively improved the clinical symptoms of Alzheimer’s disease.In the present study,we established a model of Alzheimer’s ...One of our previous studies showed that Yizhijiannao Granule,a compound Chinese medicine, effectively improved the clinical symptoms of Alzheimer’s disease.In the present study,we established a model of Alzheimer’s disease using beta-amyloid（25-35）in PC12 cells,and treated the cells with Yizhijiannao Granule and its four monomers,i.e.,icariin,catechin,Panax notoginseng saponins,and eleutheroside E.Flow cytometry showed that Yizhijiannao Granule-containing serum, icariin,Panax notoginseng saponins,and icariin＋Panax notoginseng saponins were protective against beta-amyloid（25-35）-induced injury in PC12 cells.Icariin in combination with Panax notoginseng saponins significantly inhibited early apoptosis of PC12 cells with beta-amyloid （25-35）-induced injury compared to icariin or Panax notoginseng saponins alone.The effects of icariin＋Panax notoginseng saponins were similar to the effects of Yizhijiannao Granule.The findings indicate that two of the effective monomers of Yizhijiannao Granule,icariin and Panax notoginseng saponins,can synergistically inhibit early apoptosis of PC12 cells induced by beta-amyloid（25-35）.展开更多
BACKGROUND： Tyrosine hydroxylase and phenylethanolamine-n-methyl transferase expression coexist in Purkinje cells of the rat cerebellum. Numerous reports have also been published addressing whether dopamine-beta-hydr...BACKGROUND： Tyrosine hydroxylase and phenylethanolamine-n-methyl transferase expression coexist in Purkinje cells of the rat cerebellum. Numerous reports have also been published addressing whether dopamine-beta-hydroxylase （DBH） expression exists in cerebellar Purkinje cells. OBJECTIVE： To investigate the coexistence of DBH and activator protein-2α expression in rat cerebellar Purkinje cells. DESIGN, TIME AND SETTING： A cell morphological study was performed at the Institute of Neuroscience, Chongqing Medical University, China in May 2007. MATERIALS： Ten healthy Wistar rats, of either gender, aged 14 weeks, served as experimental animals. Rabbit anti-mouse DBH, goat anti-mouse activator protein-2α and rabbit anti-mouse β-actin （Santa Cruz Biotechnology, Inc., USA）, horseradish peroxidase-labeled goat anti-rabbit IgG, FITC-labeled mouse anti-rabbit IgG, and Cy3-labeled mouse anti-goat IgG （Boster, Wuhan, China）, were used in this study. METHODS： Immunohistochemical staining was used to measure the expression of DBH or activator protein-2α, with double-label immunofluorescence being employed to determine coexpression of both, in the cerebellum of 5 randomly selected rats. Western blot assay was utilized to determine the expression of DBH and activator protein-2α in the cerebellum of the remaining 5 rats. MAIN OUTCOME MEASURES： Expression, localization and coexistence of DBH and activator protein-2α in the cerebellum were measured separately. RESULTS： Immunohistochemical staining demonstrated that cerebellar Purkinje cells stained positive for DBH and activator protein-2α. Western blot assay also demonstrated DBH and activator protein-2α expression in the cerebellum. Double-labeling immunofluorescence showed the coexistence of DBH and activator protein-2α in cerebellar Purkinje cells. CONCLUSION： Norepinephrine and activator protein-2α coexist in rat cerebellar Purkinje cells.展开更多
Objective To explore the toxicological mechanism of hydroquinone in human bronchial epithelial cells and to investigate whether DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone. M...Objective To explore the toxicological mechanism of hydroquinone in human bronchial epithelial cells and to investigate whether DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone. Methods DNA polymerase beta knock-down cell line was established via RNA interference as an experimental group. Normal human bronchial epithelial cells and cells transfected with the empty vector of pEGFP-C1 were used as controls. Cells were treated with different concentrations of hydroquinone （ranged from 10 μmol/L to 120 μmol/L） for 4 hours. MTT assay and Comet assay [single-cell gel electrophoresis （SCGE）] were performed respectively to detect the toxicity of hydroquinone. Results assay showed that DNA polymerase beta knock-down cells treated with different concentrations of hydroquinone had a lower absorbance value at 490 nm than the control cells in a dose-dependant manner. Comet assay revealed that different concentrations of hydroquinone caused more severe DNA damage in DNA polymerase beta knock-down cell line than in control cells and there was no significant difference in the two control groups. Conclusions Hydroquinone has significant toxicity to human bronchial epithelial cells and causes DNA damage. DNA polymerase beta knock-down cell line appears more sensitive to hydroquinone than the control cells. The results suggest that DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone.展开更多
基金Supported by Mexican Federal Funds HIM,No.2018/068 SSA152.
文摘BACKGROUND Autoimmunity has emerged as a probable disease modifier in patients with clinically diagnosed type 2 diabetes mellitus(T2DM),that is,patients who have insulin resistance,obesity,and other cardiovascular risk factors,suggesting that the presence of glutamic acid decarboxylase(anti-GAD65),islet antigen 2(anti-IA2),and zinc transporter 8(anti-Zn8T)antibodies could have deleterious effects on beta cell function,causing failure and earlier requirement for insulin treatment.AIM To evaluate anti-GAD65,anti-IA2 and anti-Zn8T as predictors of early insulin requirement in adolescents with a clinical diagnosis of T2DM.METHODS This was a case–control study in patients with clinically diagnosed with T2DM(68 cases and 64 controls with and without early insulin dependence respectively),male and female,aged 12–18 years.Somatometry,blood pressure,glucose,insulin,C-peptide,glycated hemoglobin A1c,and lipid profiles were assessed.ELISA was used to measure anti-GAD65,anti-IA2,and anti-Zn8T antibodies.Descriptive statistics,Pearson'sχ2 test,Student's t test,and logistic regression was performed.P<0.05 was considered statistically significant.RESULTS There were 132 patients(53.8%female),with a mean age was 15.9±1.3 years,and there was a disease evolution time of 4.49±0.88 years.The presence of anti-GAD65,anti-IA2,and anti-Zn8T positivity was found in 29.5%,18.2%,and 15.9%,respectively.Dividing the groups by early or no insulin dependence showed that the group with insulin had a higher frequency of antibody positivity:anti-GAD65 odds ratio(OR):2.42(1.112–5.303,P=0.026);anti-IA2:OR:1.55(0.859–2.818,P=0.105);and anti-Zn8T:OR:7.32(2.039–26.279,P=0.002).CONCLUSION Anti-GAD65 positivity was high in our study.Anti-GAD65 and anti-Zn8T positivity showed a significantly depleted beta cell reserve phenotype,leading to an increased risk of early insulin dependence.
基金Supported by Funding of the National Institutes of Healththe Juvenile Diabetes Research Foundation+2 种基金the American Diabetes Associationthe Foundation for Diabetes Researchthe Diabetes Research Institute Foundation
文摘If only at a small scale,islet transplantation has successfully addressed what ought to be the primary endpoint of any cell therapy:the functional replenishment of damaged tissue in patients.After years of less-thanoptimal approaches to immunosuppression,recent advances consistently yield long-term graft survival rates comparable to those of whole pancreas transplantation.Limited organ availability is the main hurdle that stands in the way of the widespread clinical utilization of this pioneering intervention.Progress in stem cell research over the past decade,coupled with our decades-long experience with islet transplantation,is shaping the future of cell therapies for the treatment of diabetes.Here we review the most promising avenues of research aimed at generating an inexhaustible supply of insulin-producing cells for islet regeneration,including the differentiation of pluripotent and multipotent stem cells of embryonic and adult origin along the beta cell lineage and the direct reprogramming of non-endocrine tissues into insulin-producing cells.
基金supported by the Korea Health Industry Development Institute(KHIDI)funded by the Ministry of Health&Welfare,Republic of Korea(No.HH21C0011)Gachon University Gil Medical Center(No.FRD 2021-02)。
文摘Type 1 diabetes is caused by insulin deficiency due to the loss of beta cells in the islets of Langerhans.In severe cases,islet transplantation into the portal vein is performed.However,due to the loss of transplanted islets and the failure of islet function,the 5-year insulin independence rate of these patients is<50%.In this study,we developed a long-term,insulin-secreting,3 Dbioprinted construct implanted subcutaneously with the aim of preventing islet loss.The bioprinted construct was fabricated by the multi-layer bioprinting of beta-cell(mouse insulinoma-6:MIN-6)-encapsulated alginate bioink and poly(caprolactone)biodegradable polymer.A glucose response assay revealed that the bioprinted constructs proliferated and released insulin normally during the 4-week in vitro period.Bioprinted MIN-6 generated clusters with a diameter of 100-200μm,similar to the original pancreatic islets in the construct.In an in vivo study using type 1 diabetes mice,animals implanted with bioprinted constructs showed three times higher insulin secretion and controlled glucose levels at 8 weeks after implantation.Because the implanted,bioprinted constructs had a positive effect on insulin secretion in the experimental animals,the survival rate of the implanted group(75%)was three times higher than that of the non-implanted group(25%).The results suggest that the proposed,3 D-bioprinted,subcutaneous construct can be a better alternative to portal vein islet transplantation.
文摘Background: Catalase deficiency (acatalasemia) is sensitive to alloxan, and the administration to acatalasemic mice develops hyperglycemia under mild conditions. However, the mechanism is still poorly understood. Methods: Alloxan was used to induce the oxidative stress and intraperitoneally administered to acatalasemic and normal mice. The blood samples of these mice after 1, 3, 5 and 7 days were examined. The pancreatic islets 7 days after alloxan administration were isolated, and the insulin released under 3 mM and 20 mM glucose was examined. Results: After alloxan administration, increase of oxidative markers in blood and pancreatic apoptosis in acatalasemic mice were observed immediately. Insulin in blood was lowered after 3 days, and the insulin in acatalasemic mice was lower than that in normal mice. Hyperglycemia in the acatalasemic mice was observed after 3 days. The pancreatic islets after 7 days were isolated. A reduction of the insulin released from the islets under glucose stimulation was observed. The stimulation indexes of the normal and acatalasemic mice were 1.4 ± 0.6 and 0.7 ± 0.3, respectively. Conclusions: Alloxan induced a deterioration of glucose-dependent insulin secretion ability from the islets, and the deterioration mostly contributed to hyperglycemia, rather than apoptosis.
文摘Chronic pancreatitis is best described as a relentless, continuous inflammatory destruction of the pancreas parenchyma, characterized by irreversible destruction of the exocrine tissues, fibrosis, and at the late stage, the destruction of endocrine cells. Current therapies for chronic pancreatitis patients focus on pain relief by medical and minimally invasive endoscopic treatment as well as surgical management with resection of diseased parenchyma and drainage of obstructed ducts. Radical treatment of chronic pancreatitis has been successful with total pancreatictomy and islet autotransplantation (TP-IAT) that may prevent maladaptive intractable pain pathways and also avoid pancreatogenic diabetes in the well-selected patient. Distinct loss of pancreatic islet cells occurs in about 30%-50% of patients during the progression of chronic pancreatitis when severe fibrosis develops at the late stage of the disease. Profound β cell apoptosis induced by stresses encountered during islet isolation and transplantation further compromises β cell survival and function after TP-IAT. The molecular mechanisms that lead to β cell dysfunction in chronic pancreatitis remain largely undelineated. In this review, we summarize factors that may contribute β cell apoptosis during the disease progress and after TP-IAT and discuss potential interventional approaches that may prevent islet cell death during these processes. Such information is critical to the development of therapeutic protocols that can preserve the viability and function of β cell in patients with chronic pancreatitis.
文摘Background: Diabetes and diabetes-related complications are major causes of morbidity and mortality in the United States. Depressive symptoms and perceived stress have been identified as possible risk factors for beta cell dysfunction and diabetes. The purpose of this study was to assess associations between depression symptoms and perceived stress with beta cell function between African and Haitian Americans with and without type 2 diabetes. Participants and Methods: Informed consent and data were available for 462 participants (231 African Americans and 231 Haitian Americans) for this cross-sectional study. A demographic questionnaire developed by the Primary Investigator was used to collect information regarding age, gender, smoking, and ethnicity. Diabetes status was determined by self-report and confirmed by fasting blood glucose. Anthropometrics (weight, and height and waist circumference) and vital signs (blood pressure) were taken. Blood samples were drawn after 8 10 hours over-night fasting to measure lipid panel, fasting plasma glucose and serum insulin concentrations. The homeostatic model assessment, version 2 (HOMA2) computer model was used to calculate beta cell function. Depression was assessed using the Beck Depression Inventory-II (BDI-II) and stress levels were assessed using the Perceived Stress Scale (PSS). Results: Moderate to severe depressive symptoms were more likely for persons with diabetes (p = 0.030). There were no differences in perceived stress between ethnicity and diabetes status (p = 0.283). General linear models for participants with and without type 2 diabetes using beta cell function as the dependent variable showed no association with depressive symptoms and perceived stress;however, Haitian Americans had significantly lower beta cell function than African Americans both with and without diabetes and adjusting for age, gender, waist circumference and smoking. Further research is needed to compare these risk factors in other race/ethnic groups.
文摘Diabetes mellitus,characterized by chronic hyperglycemia due to insulin deficiency or resistance,poses a significant global health burden.Central to its pathogenesis is the dysfunction or loss of pancreatic beta cells,which are res-ponsible for insulin production.Recent advances in beta-cell regeneration research offer promising strategies for diabetes treatment,aiming to restore endogenous insulin production and achieve glycemic control.This review explores the physiological basis of beta-cell function,recent scientific advan-cements,and the challenges in translating these findings into clinical applications.It highlights key developments in stem cell therapy,gene editing technologies,and the identification of novel regenerative molecules.Despite the potential,the field faces hurdles such as ensuring the safety and long-term efficacy of regen-erative therapies,ethical concerns around stem cell use,and the complexity of beta-cell differentiation and integration.The review highlights the importance of interdisciplinary collaboration,increased funding,the need for patient-centered approaches and the integration of new treatments into comprehensive care strategies to overcome these challenges.Through continued research and collab-oration,beta-cell regeneration holds the potential to revolutionize diabetes care,turning a chronic condition into a manageable or even curable disease.
基金supported by grants from the National Natural Science Foundation of China(grant number 82170838,82370873)Open Research Fund Program of the State Key Laboratory of Virology of China(grant number 2018IOV003).
文摘The association between chronic HCV infection and type 2 diabetes mellitus(T2DM)has been established;however,there is limited research onβ-cell function particularly in the pre-diabetic population.Here,we evaluated indices ofβ-cell function and insulin sensitivity across the spectrum from normal glucose tolerance to T2DMin individuals with and without chronic hepatitis C(CHC),and the effects of antiviral treatments on these variables.A total of 153 noncirrhotic,non-fibrotic CHC patients with a BMI<25 were enrolled in the study.Among them,119 were successfully treated with either direct acting antiviral(DAA)drugs or pegylated interferon/ribavirin(IFN/RBV)anti-HCV therapy.Fasting state-and oral glucose tolerance test(OGTT)-derived indexes were used to evaluateβ-cell function and insulin sensitivity.Among all subjects,19(13%)had T2DM and 21%exhibited pre-diabetes including 8%isolated impaired fasting glucose(IFG)and 13%combined IFG and impaired glucose tolerance(IGT).Early and total insulin secretion adjusted for the degree of insulin resistance were decreased in pre-diabetic CHC patients compared to HCVuninfected individuals.Viral eradication through DAA or IFN/RBV therapy demonstrated positive impacts on insulin sensitivity andβ-cell function in CHC patients who achieved sustained virologic response(SVR),regardless of fasting or OGTT state.These findings emphasize the role of HCV in the development ofβ-cell dysfunction,while also suggesting that viral eradication can improve insulin secretion,reverse insulin resistance,and ameliorate glycemic control.These results have important implications for managing pre-diabetic CHC patients and could prevent diabetes-related clinical manifestations and complications.
文摘Background Type 2 diabetes is a chronic disease characterized by a progressive loss of beta cell functions. However, the evaluation of beta cell functions is either expensive or inconvenient for clinical practice. We aimed to elucidate the association between the changes of insulin responsiveness and the fasting plasma glucose （FPG） during the development of diabetes. Methods A total of 1192 Chinese individuals with normal blood glucose or hyperglycemia were enrolled for the analysis. The early insulinogenic index （△I30/△G30）, the area under the curve of insulin （AUC-Ⅰ）, and homeostasis model assessment were applied to evaluate the early phase secretion, total insulin secretion, and insulin resistance respectively. Polynomial regression analysis was performed to estimate the fluctuation of beta cell functions. Results The △I30/△G30 decreased much more rapidly than the AUC-Ⅰ accompanying with the elevation of FPG. At the FPG of 110 mg/dl （a pre-diabetic stage）, the AI30/AG30 lost 50% of its maximum while the AUC-Ⅰ was still at a compensated normal level. The AUC-Ⅰ exhibited abnormal and decreased gradually at the FPG of from 130 mg/dl to higher （overt diabetes）, while the △I30/△G30 almost remained at 25% of its maximum value. When hyperglycemia continuously existed at 〉 180 mg/dl, both the AI30/AG30 and AUC-Ⅰ were totally lost. Conclusion The increased fasting plasma glucose reflects progressive decompensation of beta cell functions, and could be used to guide the strategy of clinical treatments.
基金Supported by National Natural Science Foundation of China,No.81300286 to Liu SZ and No.81471019 to Hu SYFoundation for Outstanding Young Scientist in Shandong Province,No.BS2013YY031 to Liu SZ+1 种基金Science and Technology Development Program of Shandong Province,No.2014GGE27485 to Liu SZSpecialized Research Fund for the Doctoral Program of Higher Education of China,No.20130131120069 to Liu SZ
文摘AIM To investigate factors causing diabetes recurrence after sleeve gastrectomy(SG)and duodenal-jejunal bypass(DJB).METHODS SG and DJB were performed on rats with diabetes induced by high-fat diet(HFD)and streptozotocin(STZ).HFD was used to induce diabetes recurrence at 4 wk postoperatively.Body weight,oral glucose tolerance test,homeostatic model assessment of insulin resistance(HOMA-IR),insulin signaling[IR,insulin receptor substrate(IRS 1,IRS2,phosphatidylinositol3-kinase and AKT in liver and skeletal muscle],oral glucose stimulated insulin secretion,beta-cell morphology(mass,apoptosis and insulin secretion),glucagon-like peptide(GLP)-1,PYY and ghrelin were compared among SG rats with common low-fat diet(SG-LFD),SG with HFD(SG-HFD),DJB rats with LFD(DJB-LFD),DJB with HFD(DJB-HFD)and shamoperation with LFD(Sham)at targeted postoperative times.RESULTS SG and DJB resulted in significant improvement in glucose tolerance,lower HOMA-IR,up-regulated hepatic and muscular insulin signaling,higher levels of oral glucose-stimulated insulin secretion,bigger betacell mass,higher immunofluorescence intensity of insulin,fewer transferase-mediated d UTP-biotin 3’nick end-labeling(TUNEL)-positive beta cells and higher postprandial GLP-1 and PYY levels than in the Sham group.The improvement in glucose tolerance was reversed at 12 wk postoperatively.Compared with the SG-LFD and DJB-LFD groups,the SG-HFD and DJB-HFD groups showed higher HOMA-IR,down-regulated hepatic and muscular insulin signaling,and more TUNEL-positive beta cells.No significant difference was detected between HFD and LFD groups for body weight,glucose-stimulated insulin secretion,betacell mass,immunofluorescence intensity of insulin,and postprandial GLP-1 and PYY levels.Fasting serum ghrelin decreased in SG groups,and there was no difference between HFD-SG and LFD-SG groups.CONCLUSION HFD reverses the improvement in glucose homeostasis after SG and DJB.Diabetes recurrence may correlate with re-impaired insulin sensitivity,but not with alterations of beta-cell function and body weight.
基金Acknowledgements： This study was supported by EFSD Grant Award for Collaborative Diabetes Research between China and Europe supported by Bristol-Myers-Squibb to LI Dai-qing and Tianjin Municipal Natural Science Foundation to LI Dai-qing （No. 08JCZDJC25100 ）.
文摘Background A 65-kD mdrl （multi-drug resistance protein 1, P-glycoprotein）-Iike protein has been suggested to be the regulatory protein to the chloride channel protein 3 （CIC-3） mediating insulin granules acidification and release in mouse pancreatic beta cells. But the protein has not been deeply investigated. In this study, we identified existence of the 65-kda protein in rat islets and preliminarily explored its biological functions. Methods Total RNAs of rat kidneys served as positive controls, and pancreas, islets and INS-1 cells were extracted for reverse-transcript PCR （RT-PCR）, respectively. The cDNAs were run with specific primers selected from the mRNA of abcblb encoding P-glycoprotein. All PCR products were visualized in agarose gel electrophoresis and sequenced. Homogenates of rat islets and INS-1 cells were applied to SDS-PAGE. P-glycoprotein was detected by a specific monoclonal antibody, C219. Biphasic insulin release was measured in static incubations of rat islets with radioimmunology assay. Results Compared with positive control, expression of the P-glycoprotein mRNA segments were detected in the islets, INS-1 cells and pancreas. Sequence analysis confirmed that the PCR products were matched with mRNA of P-glycoprotein. A 65-kda protein was recognized by the antibody in the islets homogenate but not in that of INS-1 cells in Western-blotting. Instead, the homogenate of INS-1 cells contained a 160-kda protein recognized by the antibody. Insulin secretion of rat islets were stimulated by high glucose （16.7mmol/L）, and showed biphasic curve during 60-minute incubation. After co-incubation with cyclosporine A （CsA）, specific inhibitor to P-glycoprotein, the second phase of insulin secretion was reduced significantly while the first phase was not influenced. Conclusions The 65-kda protein expressed in rat islets is most likely a mini-P-glycoprotein. It may play a key role regulating biphasic insulin release.
基金This study was supported by grants from Fund of Capital Medical Development and Research （No. 2009-1020） and Tsinghua-Yue-Yuen Medical Science Foundation （No.20240000531 and No.20240000568）
文摘Background Abnormal insulin secretion of pancreatic beta cells is now regarded as the more primary defect than the insulin function in the etiology of type 2 diabetes.Previous studies found impaired mitochondrial function and impaired Ca2＋ influx in beta cells in diabetic patients and animal models,suggesting a role for these processes in proper insulin secretion.The aim of this study was to investigate the detailed relationship of mitochondrial function,Ca2＋ influx,and defective insulin secretion.Methods We investigated mitochondrial function and morphology in pancreatic beta cell of diabetic KK-Ay mice and C57BL/6J mice.Two types of Ca2＋ channel activities,L-type and store-operated Ca2＋ （SOC）,were evaluated using whole-cell patch-clamp recording.The glucose induced Ca2＋ influx was measured by a non-invasive micro-test technique （NMT）.Results Mitochondria in KK-Ay mice pancreatic beta cells were swollen with disordered cristae,and mitochondrial function decreased compared with C57BL/6J mice.Ca2＋ channel activity was increased and glucose induced Ca2＋ influx was impaired,but could be recovered by genipin.Conclusion Defective mitochondrial function in diabetic mice pancreatic beta cells is a key cause of abnormal insulin secretion by altering Ca2＋ influx,but not via Ca2＋ channel activity.
基金Supported by Governor Talent Foundation of GuizhouProvince (No .2001016)
文摘Objective： To examine the protective effect of ecdysterone （ECR） against beta-amyloid peptide fragment25-35 （Aβ25-35）-induced PC12 cells cytotoxicity, and to further explore its mechanism. Methods： Experimental PC12 cells were divided into the Aβ group （treated by Aβ25-35 100μmol/L）, the blank group （untreated）, the positive control group （treated by Vit E 100 μmol/L after induction） and the ECR treated groups （treated by ECR with different concentrations of 1, 50 and 100 μmol/L）. The damaged and survival condition of PC12 cells in various groups was monitored by lactate dehydrogenase （LDH） release and MTT assay. The content of malondialdehyde （MDA） was measured by fluorometric assay to indicate the lipid peroxidation. And the antioxidant enzymes activities in PC12 cells, including superoxide dismutases（SOD）, catalase （CAT） and glutathione peroxidase（GSH-Px）, were detected respectively. Results： After PC12 cells were treated with Aβ25-35 （100 μmol/L） for 24 hrs, they revealed a great decrease in MTT absorbance and activity of antioxidant enzymes, including SOD, CAT and GSH-Px as well as a significant increase of LDH activity and MDA content in PC12 cells （P〈0.01）. When the cells was pretreated with 1-100 μmol/L ECR for 24 hrs before Aβ25-35 treatment, the above-mentioned cytotoxic effect of Aβ25-35 could be significantly attenuated dose-dependently, for ECR 50 μmol/L, P〈0.05 and for ECR 100 μmol/L, P〈0.01. Moreover, ECR also showed significant inhibition on the Aβ25-35 induced decrease of SOD and GSH-Px activity, but not on that of CAT. Conclusion： ECR could protect PC12 cells from cytotoxicity of Aβ25-35, and the protective mechanism might be related to the increase of SOD and GSH-Px activities and the decrease of MDA resulting from the ECR-pretreatment.
基金supported by grants from the Natural Science Foundation of Jiangsu Province,China (No. BK2006241)the Foundation for Talents in Six Fields of Jiangsu Province (No. 07-B-038)
文摘BACKGROUND: Pancreatic stellate cells (PSCs) play a major role in promoting pancreatic fibrosis. Transforming growth factor beta 1 (TGF-beta 1) is a critical mediator of this process. This study aimed to determine the expression of the Smad3 and Smad7 genes in the process of PSC activation, and explore the mechanisms of chronic pancreatitis. METHODS: The expressions of Smad3 and Smad7 in PSCs before and after TGF-beta 1 treatment were detected by reverse transcription-polymerase chain reaction and Western blotting analysis. Smad3 expression was detected in PSCs after treatment with 5 ng/ml of TGF-beta 1 for 24 hours. RESULTS: Smad7 expression was decreased in TGF-beta 1 -activated PSCs (P<0.05) in a dose-dependent manner. When TGF-beta 1 concentration reached 10 ng/ml, the expression of p-Smad3, Smad3, and Smad7 was inhibited (P<0.05). CONCLUSIONS: TGF-beta 1 promotes the expression of Smad3 and inhibits the expression of Smad7 during the activation of PSCs. In contrast, high-dose TGF-beta 1 downregulates the expression of Smad3 in completely activated PSCs.
基金Supported by a local grant from the University of Greenwich(GRE Mini-Proof-of-Concept No.HEIF-Po C-SCI-02/13)
文摘Objective: To investigate the antioxidant, anti-a-glucosidase and pancreatic b-cell protective potential of Ensete superbum(E. superbum) seeds.Methods: A variety of in vitro assays including radical scavenging, reducing power potential, phenolic content determination, a-glucosidase assay and pancreatic b-cell(1.4E7 cells) viability were employed for assessing the effect of methanolic extract of E. superbum seeds.Results: The radical scavenging and reducing power effects comparable with the standard rutin were obtained while the enzyme inhibitory activity of the extract was 68-fold better than the standard antidiabetic drug, acarbose. The seed extract of E. superbum was packed-full of polyphenols with mean percentage gallic acid equivalent value of(38.2 ± 1.8)(n = 3). The protection of pancreatic cells from massive onslaught of hydrogen peroxide was far superior to that obtained for rutin.Conclusions: The reputed antidiabetic therapeutic uses of the seeds extract of E. superbum may be justified on the basis of inhibition of carbohydrate enzymes, antioxidant effects and pancreatic b-cell protection.
基金Supported by the National Natural Science Foundation of China(No.81430009No.81400424)the Science and Technology Research and Development Project of Shaanxi Province(No.2014K11-03-07-04)
文摘AIM：To identify the pathological role of amyloid beta（Aβ） deposition in retinal degeneration,and explore Aβ deposition on the retinal pigment epithelium cells（RPE） layer and the associated structural and functional changes in Alzheimer＇s disease transgenic mice.METHODS：RPE changes in the eyes of APPswe/PS1 transgenic and none transgenic（NTG） mice over 20 months old were examined.Histological changes were investigated via hematoxylin and eosin（H＆E） staining and transmission electron microscopy（TEM） examination,whereas the expression of amyloid precursor protein（APP）,Aβ,Zonula occludens-1（ZO-1） and Ionized calcium binding adaptor molecule-1（IBA-1） were investigated using immunohistochemistry and immunofluorescence techniques.All of the obtained results were quantitatively and statistically analyzed.RESULTS：In aged transgenic mice,an APP-positive immunoreaction and Aβ deposition were detected on the RPE layer but were undetectable in NTG mice.The RPE demonstrated some vacuole changes,shortened basal infoldings and basal deposition in histopathological examination and TEM tests,wherein irregular shapes were indicated by ZO-1 disorganization through fluorescence.Furthermore,IBA-1 positive cells were observed to have accumulated and infiltrated into the RPE layer and localized beneath the RPE/Bruch＇s membrane（Br M） complex,which was accompanied by an increase in BrM thickness in aged transgenic mice in comparison to NTG mice.The IBA-1 positive cells were found to be co-stained with Aβ deposition on the RPE flat mounts.CONCLUSION：The observed Aβ deposition in the RPE layer may cause RPE dysfunction,which is associated with microglia cells infiltration into the retina of aged transgenic mice,suggesting that Aβ deposition probably plays a significant role in RPE-related degenerative disease.
文摘One of our previous studies showed that Yizhijiannao Granule,a compound Chinese medicine, effectively improved the clinical symptoms of Alzheimer’s disease.In the present study,we established a model of Alzheimer’s disease using beta-amyloid（25-35）in PC12 cells,and treated the cells with Yizhijiannao Granule and its four monomers,i.e.,icariin,catechin,Panax notoginseng saponins,and eleutheroside E.Flow cytometry showed that Yizhijiannao Granule-containing serum, icariin,Panax notoginseng saponins,and icariin＋Panax notoginseng saponins were protective against beta-amyloid（25-35）-induced injury in PC12 cells.Icariin in combination with Panax notoginseng saponins significantly inhibited early apoptosis of PC12 cells with beta-amyloid （25-35）-induced injury compared to icariin or Panax notoginseng saponins alone.The effects of icariin＋Panax notoginseng saponins were similar to the effects of Yizhijiannao Granule.The findings indicate that two of the effective monomers of Yizhijiannao Granule,icariin and Panax notoginseng saponins,can synergistically inhibit early apoptosis of PC12 cells induced by beta-amyloid（25-35）.
基金the National Natural Science Foundation of China.No.30270437
文摘BACKGROUND： Tyrosine hydroxylase and phenylethanolamine-n-methyl transferase expression coexist in Purkinje cells of the rat cerebellum. Numerous reports have also been published addressing whether dopamine-beta-hydroxylase （DBH） expression exists in cerebellar Purkinje cells. OBJECTIVE： To investigate the coexistence of DBH and activator protein-2α expression in rat cerebellar Purkinje cells. DESIGN, TIME AND SETTING： A cell morphological study was performed at the Institute of Neuroscience, Chongqing Medical University, China in May 2007. MATERIALS： Ten healthy Wistar rats, of either gender, aged 14 weeks, served as experimental animals. Rabbit anti-mouse DBH, goat anti-mouse activator protein-2α and rabbit anti-mouse β-actin （Santa Cruz Biotechnology, Inc., USA）, horseradish peroxidase-labeled goat anti-rabbit IgG, FITC-labeled mouse anti-rabbit IgG, and Cy3-labeled mouse anti-goat IgG （Boster, Wuhan, China）, were used in this study. METHODS： Immunohistochemical staining was used to measure the expression of DBH or activator protein-2α, with double-label immunofluorescence being employed to determine coexpression of both, in the cerebellum of 5 randomly selected rats. Western blot assay was utilized to determine the expression of DBH and activator protein-2α in the cerebellum of the remaining 5 rats. MAIN OUTCOME MEASURES： Expression, localization and coexistence of DBH and activator protein-2α in the cerebellum were measured separately. RESULTS： Immunohistochemical staining demonstrated that cerebellar Purkinje cells stained positive for DBH and activator protein-2α. Western blot assay also demonstrated DBH and activator protein-2α expression in the cerebellum. Double-labeling immunofluorescence showed the coexistence of DBH and activator protein-2α in cerebellar Purkinje cells. CONCLUSION： Norepinephrine and activator protein-2α coexist in rat cerebellar Purkinje cells.
基金This work was supported by a grant from the Major State Basic Research Development Program of China (No. 2002CB512904, 2002CB512903).
文摘Objective To explore the toxicological mechanism of hydroquinone in human bronchial epithelial cells and to investigate whether DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone. Methods DNA polymerase beta knock-down cell line was established via RNA interference as an experimental group. Normal human bronchial epithelial cells and cells transfected with the empty vector of pEGFP-C1 were used as controls. Cells were treated with different concentrations of hydroquinone （ranged from 10 μmol/L to 120 μmol/L） for 4 hours. MTT assay and Comet assay [single-cell gel electrophoresis （SCGE）] were performed respectively to detect the toxicity of hydroquinone. Results assay showed that DNA polymerase beta knock-down cells treated with different concentrations of hydroquinone had a lower absorbance value at 490 nm than the control cells in a dose-dependant manner. Comet assay revealed that different concentrations of hydroquinone caused more severe DNA damage in DNA polymerase beta knock-down cell line than in control cells and there was no significant difference in the two control groups. Conclusions Hydroquinone has significant toxicity to human bronchial epithelial cells and causes DNA damage. DNA polymerase beta knock-down cell line appears more sensitive to hydroquinone than the control cells. The results suggest that DNA polymerase beta is involved in protecting cells from damage caused by hydroquinone.
