This study was performed to observe the changes of glucose-related hormones and the morphological change including ultrastructure of the pancreatic islets in the male Otsuka Long-Evans Tokushima Fatty rat. Area under the curve (AUC) of glucose at the 30th (709 +/- 73 mg.h/dL) and at the 40th week (746 +/- 87 mg.h/ dL) of age were significantly higher than that at the 10th week (360 +/- 25 mg.h/ dL). AUC of insulin of the 10th week was 2.4 +/- 0.9 ng.h/mL, increased gradually to 10.8 +/- 8.3 ng.h/mL at the 30th week, and decreased to 1.8 +/- 1.2 ng.h/mL at the 40th week. The size of islet was increased at 20th week of age and the distribution of peripheral alpha cells and central beta cells at the 10th and 20th weeks was changed to a mixed pattern at the 40th week. On electron microscopic examination, beta cells at the 20th week showed many immature secretory granules, increased mitochondria, and hypertrophied Golgi complex and endoplasmic reticulum. At the 40th week, beta cell contained scanty intracellular organelles and secretory granules and apoptosis of acinar cell was observed. In conclusion, as diabetes progressed, increased secretion of insulin was accompanied by increases in size of islets and number of beta-cells in male OLETF rats showing obese type 2 diabetes. However, these compensatory changes could not overcome the requirement of insulin according to the continuous hyperglycemia after development of diabetes.
Animals ; Body Weight ; Diabetes Mellitus, Type 2/*metabolism/pathology ; Disease Models, Animal ; Glucagon/*metabolism ; Insulin/*metabolism ; Islets of Langerhans/*metabolism/pathology/ultrastructure ; Male ; Rats ; Rats, Inbred OLETF

OBJECTIVETo investigate the effects of various HIV protease inhibitors on the function of pancreatic beta-cells.

METHODSRat insulinoma INS-1 cells were incubated with different concentrations of ritonavir or amprenavir for 48 h and stimulated with 20 mmol/L D-glucose for 30 min. The rate of insulin release was measured in the supernatant by ELISA, normalized to cellular DNA contents. Cells were counted with trypan blue and MTT test were determined to evaluate the effect of protease inhibitors on cell viability.

RESULTRitonavir treatment significantly decreased baseline insulin release and glucose-stimulated insulin release in a dose-dependent manner (r=-0.861, -0.839, both P<0.01). For 10 micromol/L of ritonavir, the decrease rate of baseline insulin secretion and glucose-stimulated insulin secretion was 46% and 47%, respectively. Amprenavir had no effect on the rate of insulin release.

CONCLUSIONVarious HIV protease inhibitors present different effect on the insulin release of pancreatic beta-cells.

Animals ; Carbamates ; pharmacology ; HIV Protease Inhibitors ; pharmacology ; Insulin ; secretion ; Insulinoma ; metabolism ; pathology ; Islets of Langerhans ; metabolism ; Pancreatic Neoplasms ; metabolism ; pathology ; Rats ; Ritonavir ; pharmacology ; Sulfonamides ; pharmacology

OBJECTIVETo explore the synergistic protective effect of co-transplanted testicular cells expressing FasL and CsA on survival of islet allografts.

METHODSThe allogeneic islets and testicular cells were co-transplanted into the renal subcapsular space of the diabetic recipients with or without CsA after operation. Allografts survival period and the testicular cells or islets function were analyzed.

RESULTSThe mean survival period of control group was 4.6 +/- 1.1 days. When CsA was administered after transplantation, the mean survival period of islet allografts, (21.8 +/- 4.7) days, was significantly longer than that of control group (P < 0.01). When islets were co-transplanted together with 1 x 10(7) testicular cells (group A), a significant prolongation of graft survival was found (more than 57.5 +/- 4.0 days; P < 0.01 vs. control). But if 1 x 10(7) testicular cells expressing FasL were cultured with FasL-mAb for 30 minutes before co-transplantation (group B), the mean survival period of islet allografts (5.8 +/- 2.6 days), was similar to that in control group, but significantly shorter than that in group A (P < 0.01). When islets and 1 x 10(5) testicular cells were co-transplanted separately into the bilateral renal subcapsular space with CsA (group C), the survival of islet allografts was significantly prolonged in comparison with control group (more than 55.0 +/- 6.5 days; P < 0.01 vs. control), and similar to islets co-transplanted together with 1 x 10(7) testicular cells (group A). When islets were co-transplanted separately with 1 x 10(6) testicular cells without CsA (group D), the mean survival period (11.5 +/- 3.1 days) was shorter than that in group C, but prolonged in comparison to control group (P < 0.05).

CONCLUSIONThe co-transplanted testicular cells expressing FasL with administering CsA post-transplantation can jointly inhibit immune rejection of islet allografts by different mechanism and play a systemic and synergistic protective role to islet allografts.

Animals ; Cyclosporine ; therapeutic use ; Fas Ligand Protein ; Graft Survival ; Immunohistochemistry ; Insulin ; blood ; Islets of Langerhans ; pathology ; ultrastructure ; Islets of Langerhans Transplantation ; Male ; Membrane Glycoproteins ; analysis ; genetics ; Rats ; Rats, Sprague-Dawley ; Rats, Wistar ; Sertoli Cells ; metabolism ; transplantation ; Transplantation, Homologous

As a member of the apolipoprotein C (ApoC) family with a relatively high content, ApoC3 plays a major role in the regulation of triglyceride metabolism, and plays an important role in the occurrence and development of cardiovascular diseases, glucose and lipid metabolism disorders. Nonalcoholic fatty liver disease (NAFLD) refers to the accumulation of a large amount of fat in the liver in the absence of a history of chronic alcohol consumption or other damage to the liver. A large number of previous studies have shown that there is a correlation between the gene polymorphism and high expression of ApoC3 and NAFLD. In the context of hypertriglyceridemia (HTG), this article reviews the relationship between ApoC3 and NAFLD, glucose and lipid metabolism, and islet β cell function, showing that ApoC3 can not only inhibit lipoprotein lipase (LPL) and hepatic lipase (HL) activity, delay the decomposition of triglyceride in plasma to maintain the body's energy metabolism during fasting, but also be significantly increased under insulin resistance, prompting the liver to secrete a large amount of very low-density lipoprotein (VLDL) to induce HTG. Therefore, targeting and inhibiting ApoC3 might become a new approach to treat HTG. Increasing evidence suggests that ApoC3 does not appear to be an independent "contributor" to NAFLD. Similarly, our previous studies have shown that ApoC3 is not an independent factor triggering islet β cell dysfunction in ApoC3 transgenic mice, but in a state of excess nutrition, HTG triggered by ApoC3 high expression may exacerbate the effects of hyperglycemia and insulin resistance on islet β cell function, and the underlying mechanism remains to be further discussed.
Apolipoprotein C-III/genetics* ; Non-alcoholic Fatty Liver Disease/pathology* ; Glucose/metabolism* ; Lipid Metabolism ; Humans ; Animals ; Hypertriglyceridemia/metabolism* ; Islets of Langerhans/metabolism*

OBJECTIVETo investigate the effect of iNOS gene on cell apoptosis and insulin secretion of pancreas islet in rats by RNA inference (RNAi).

METHODSIslets obtained from thirty Wistar rats were randomly divided into five groups, and siRNA oligo was purchased from Genepharma in Shanghai. The cultured islets were transfected with iNOS siRNA, and then were divided into five groups. Islet cultured only was taken as blank control group, and cultured with TNF-alpha + IL-1 beta as cytokine group. Islet transfected with negative or iNOS siRNA were taken as negative transfection control group or RNAi group, while that transfected with iNOS siRNA and cultured with TNF-alpha + IL-1 beta as RNAi + cytokine group. Expression of iNOS mRNA was evaluated by RT-PCR and iNOS protein was evaluated by Western blot to detect the effect of RNAi. The expression of apoptosis correlated gene, Bax, Fas were analyzed, and the apoptotic cells were identified by TUNEL method meanwhile. Insulin secretion index assay the function of the islets.

RESULTS500 - 600 IEQ islets could be extracted from every rat. RNAi attenuated the expression of iNOS and restrained the synthesis of iNOS protein.With treatment of cytokines IL-1 beta and TNF-alpha, the level of iNOS increased remarkably, the expression of Bax and Fas ascended distinctly, and insulin secretion index decreased strikingly. While, the expression of apoptosis gene and amount of apoptotic cells descended in group of RNAi + cytokine, and insulin secretion index were satisfying.

CONCLUSIONThe apoptosis from cytokines to islets mediated by iNOS could be suppressed by RNAi, which leaded to favorable function and survival of islets.

Animals ; Apoptosis ; Cell Proliferation ; Cells, Cultured ; Islets of Langerhans ; metabolism ; pathology ; Nitric Oxide Synthase Type II ; genetics ; metabolism ; RNA Interference ; Rats ; Rats, Wistar

To investigate the semi-quantitative method for evaluating the lipid accumulation in pancreas, the KKAy mice, a classical type 2 diabetes mellitus model mice, were used and treated with rosiglitazone (Rosi); and the age-matched C57BL/6J mice were used as normal control. Pancreas was fixed quickly for histological examination with HE staining. For the estimation of the lipid accumulation in pancreas, semi-quantitative method was designed: the number and the size of islet, lipid accumulation in islet and in exocrine gland were observed and the integrative score calculated under the microscope, separately. In KKAy mice, the characteristics of the increased amount of islet, the enlarged area of islet, an abundance of large vacuolations, lipid droplets, and fat proliferation were exposed frequently, and the integrative score increased 2.1 folds compared with that in C57BL/6J mice. Meanwhile, the levels of serum glucose, insulin, and triglyceride (TG) were 1.7, 18.0, and 9.0 times as those in C57BL/6J mice, respectively. With the rosiglitazone (10 mg x kg(-1)) treatment, compared with that in KKAy mice, the pancreatic pathological changes were ameliorated significantly, and the integrative score in KKAy + Rosi mice decreased by 28.9%; and the levels of serum glucose, insulin, and triglyceride decreased by 48.3%, 81.3% and 64.1%, respectively. It showed there is a correlation between the pancreatic pathological semi-quantitative score and the values of serum parameters. In conclusion, this semi-quantitative scoring method is simple and objective for the evaluation of lipid accumulation in pancreas of mice.
Animals ; Blood Glucose ; metabolism ; Diabetes Mellitus, Type 2 ; blood ; metabolism ; pathology ; Female ; Hypoglycemic Agents ; pharmacology ; Insulin ; blood ; Islets of Langerhans ; metabolism ; pathology ; Lipid Metabolism ; drug effects ; Mice ; Mice, Inbred C57BL ; Pancreas ; metabolism ; pathology ; Random Allocation ; Thiazolidinediones ; pharmacology ; Triglycerides ; blood

Transplantation of islet cells into diabetic patients is a promising therapy, provided that the islet cells are able to evade host immune rejection. With improved islet viability, this strategy may effectively reverse diabetes. We applied 2% calcium alginate to generate small and large capsules to encapsulate porcine neonatal pancreatic cell clusters (NPCCs) using an air-driven encapsulator. After encapsulation, the viability was assessed at 1, 4, 7, 14 and 28 days and secretion of functional insulin in response to glucose stimulation were tested at days 14 and 28. Selective permeability of the small alginate capsules was confirmed using various sizes of isothiocyanate-labeled dextran (FITC-dextran). Encapsulation of NPCCs was performed without islet protrusion in the small and large capsules. The viability of NPCCs in all experimental groups was greater than 90% at day 1 and then gradually decreased after day 7. The NPCCs encapsulated in large capsules showed significantly lower viability (79.50 +/- 2.88%) than that of naive NPCCs and NPCCs in small capsule (86.83 +/- 2.32%, 87.67 +/- 2.07%, respectively) at day 7. The viability of naive NPCCs decreased rapidly at day 14 (75.67 +/- 1.75%), whereas the NPCCs encapsulated in small capsules maintained (82.0 +/- 2.19%). After 14 and 28 days NPCCs' function in small capsules (2.67 +/- 0.09 and 2.13 +/- 0.09) was conserved better compared to that of naive NPCCs (2.04 +/- 0.25 and 1.53 +/- 0.32, respectively) and NPCCs in large capsules (2.04 +/- 0.34 and 1.13 +/- 0.10, respectively), as assessed by a stimulation index. The small capsules also demonstrated selective permeability. With this encapsulation technique, small capsules improved the viability and insulin secretion of NPCCs without islet protrusion.
Alginates/chemistry/metabolism ; Animals ; Animals, Newborn ; Capsules/chemistry ; Cell Survival ; Diabetes Mellitus/pathology/*therapy ; Disease Models, Animal ; Glucuronic Acid/chemistry/metabolism ; Graft Rejection/etiology/*prevention & control ; Hexuronic Acids/chemistry/metabolism ; Humans ; Insulin/secretion ; Islets of Langerhans/*metabolism/pathology ; Islets of Langerhans Transplantation/*methods ; Postoperative Complications/etiology/*prevention & control ; *Swine

OBJECTIVETo investigate the role of T cell and its subsets in the induction of insulitis and type 1 diabetes mellitus (T1DM) in BALB/c mice.

METHODSAutoimmune diabetes mellitus was developed by intraperitoneal injection of 40 mg/kg streptozotocin (STZ) daily for 5 consecutive days in BALB/c mice as sources of donor cells. Spleen cells from diabetic mice were then cultured for 7 days in the stimulation of interleukin-2 (IL-2) to harvest diabetogenic T cells, which were subsequently transferred into normal BALB/c mice recipients. MTT, ELISA, and HE staining were used to analyze the lymphocyte proliferation, cytokine (IL-2, interferon-gamma, IL-4, and IL-10) levels, and pathological changes in pancreatic islets.

RESULTSAs few as 3 x 10(6) diabetogenic T cells successfully induced diabetes mellitus in recipients pretreated with STZ twice, whereas transfer of equal amount of normal splenocytes, T cell-depleted diabetogenic splenocytes, or diabetogenic CD4+ T cells alone in recipients receiving STZ twice pretreatment was proved not to induce diabetes mellitus either. A markedly increased lymphocyte proliferation, high levels of interferon-gamma and IL-2 in the supernatants of diabetogenic T cells were observed. In addition, a markedly enhanced lymphocyte proliferation, a high level of interferon-gamma secretion in serum, and numerous lymphocytes infiltration in pancreatic islets were detected in the diabetic mice induced by diabetogenic T cells transfer.

CONCLUSIONSA novel T1DM murine model is established in STZ-pretreated BALB/c mice by adoptive transfer of diabetogenic T cells. CD4+ T cells with interferon-gamma may promote the onset of diabetes mellitus.

Animals ; Blood Glucose ; metabolism ; Cytokines ; immunology ; Diabetes Mellitus, Experimental ; metabolism ; pathology ; Diabetes Mellitus, Type 1 ; immunology ; pathology ; Disease Models, Animal ; Islets of Langerhans ; cytology ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred BALB C ; T-Lymphocytes ; cytology ; immunology

Intraportal transplantation of islets is no longer considered to be an ideal procedure and finding the extrahepatic alternative site is becoming a subject of high priority. Herein, in this study, we would introduce our initial outcomes of using gastric submucosa (GS) and liver as sites of islet autotransplantation in pancreatectomized diabetic Beagles. Total pancreatectomy was performed in Beagles and then their own islets extracted from the excised pancreas were transplanted into GS (GS group, n=8) or intrahepatic via portal vein (PV group, n=5). Forty-eight hours post transplantation, graft containing tissue harvested from the recipients revealed the presence of insulin-positive cells. All recipients in GS group achieved euglycemia within 1 day, but returned to a diabetic state at 6 to 8 days post-transplantation (mean survival time, 7.16±0.69 days). However, all of the animals kept normoglycemic until 85 to 155 days post-transplantation in PV group (mean survival time, 120±28.58 days; P<0.01 vs. GS group). The results of intravenous glucose tolerance test (IVGTT) confirmed that the marked improvement in glycometabolism was obtained in intrahepatic islet autotransplantation. Thus, our findings indicate that the liver is still superior to the GS as the site of islet transplantation, at least in our islet autotransplant model in pancreatectomized diabetic Beagles.
Animals ; Diabetes Mellitus, Experimental ; metabolism ; pathology ; therapy ; Dogs ; Gastric Mucosa ; metabolism ; transplantation ; Glucose ; metabolism ; Glucose Tolerance Test ; Graft Survival ; Humans ; Insulin ; metabolism ; Islets of Langerhans Transplantation ; Liver ; pathology ; Liver Transplantation ; Transplantation, Autologous

OBJECTIVETo study the protective effect of islet xenograft and its possible mechanism of high expression of heme oxygenase-1 (HO-1) in donor pancreas islet induced by cobalt protoporphyrin (CoPP).

METHODSMale SD rats and C57BL/6 mouse were used as donors and recipients respectively. Donors were divided into 3 groups according to different pretreatment 24 hours before donation: control group (injected intraperitoneally with NaCl), induce group [injected intraperitoneally with cobalt-protoporphyrin (CoPP)], block group (injected intraperitoneally with CoPP and zinc protoporphyrin simultaneously). A modified approach was used for islet isolation.Recipients were rendered diabetic by intraperitoneal injection of streptozotocin. Islets were transplanted into mouse subrenal capsule. Postoperative mouse glycemia were monitored daily and normoglycemia time was compared among each group. The receptor mouse serum IL-10 was detected by ELISA approach, and real-time PCR was used to check the expression of IL-10 mRNA in islet graft tissues. The graft tissues were observed for the lymphocyte infiltration after HE staining.

RESULTSDiabetes mice accepted islets untreated, induced or blocked maintained the euglycemia for (9.3 +/- 1.4), (16.3 +/- 1.5) and (9.7 +/- 1.0) d respectively. The xeno-islets presented HO-1 over-expression survived much longer than that absent (P < 0.05), it was no significance between control group and block group (P > 0.05). The mouse islet serum IL-10 content after induction was (73.0 +/- 9.7) pg/ml, significantly higher than (30.6 +/- 3.9) pg/ml of the untreated group and (32.1 +/- 5.9) pg/ml of the blocked group (P < 0.05), there was no difference between control group and block group (P > 0.05). Moreover, the IL-10 mRNA expression up-regulated statistic significantly in HO-1 induced islet xeno-graft. Pathological examination showed that the graft lymphocyte infiltration of the induced group was obviously less serious than the other two groups.

CONCLUSIONSThe higher expression of HO-1 induced by CoPP in vivo would significantly prolong graft survival time and its mechanism could be related to immune modulation of IL-10.

Animals ; Diabetes Mellitus, Experimental ; metabolism ; pathology ; surgery ; Graft Survival ; Heme Oxygenase-1 ; drug effects ; metabolism ; Interleukin-10 ; metabolism ; Islets of Langerhans ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Pancreas Transplantation ; Protoporphyrins ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Subrenal Capsule Assay ; Transplantation, Heterologous