Effects of ginkgolide B, a platelet-activating factor inhibitor on insulitis in the spontaneously diabetic BB rat.

The BB rat spontaneously develops insulin-dependent diabetes mellitus (IDDM) in association with marked insulitis in the islet of Langerhans. Since platelet-activating factor (PAF-acether) is involved in allergic and inflammatory reactions, we tested a PAF antagonist, Ginkgolide B (BN 52021) for potential effects on islet inflammation and diabetes. Diabetes prone BB/Wor rats were treated daily from weaning at 25 days until 105 days of age with either saline (n = 30, controls), 10 (n = 25, low dose) or 20 (n = 30, high dose) mg/kg body weight of BN 52021. The overall incidence of IDDM was unaffected by treatment. Quantitative analysis of insulin area showed a dose-dependent protection of beta cells by Ginkgolide B, reflected in a 6- (low dose) to 8-fold (high dose) (P less than 0.01-0.005) increase in the insulin/glucagon cell ratio compared to the saline treated rats. Ginkgolide B reduced severe insulitis from 84% in the saline rats developing IDDM to 59% (n.s.) in the low and to 33% (P less than 0.001) in the high dose group. These data suggest that PAF inhibitors may prove useful in immunomodulator therapy of IDDM since beta cells are preserved.     

Stress response of pancreatic islets from diabetes prone BB rats of different age

Protective and/or repair mechanisms are thought to be activated in pancreatic beta cells in response to injury during insulitis. Manifestation of type-1 diabetes may depend on an imbalance between beta cell damage and repair. To prove this hypothesis, the ability of collagenase-isolated islets to respond to heat stress depending on the age of BB rats was investigated. The islets were exposed either to 44 degrees C (HS) or 37 degrees C (control) for 30 min and then kept at 37 degrees C for 5 h. Immediately and 5 h after heat shock, insulin secretion in response to 20 mmol/l glucose and total protein synthesis of heat-exposed islets were significantly diminished as compared with controls. The islet proteins were separated by SDS-PAGE followed by immunoblotting. Islets from BB rats at an age of 6-90 days responded to heat shock with the expression of major heat shock protein 70 (HSP 70). Islets from 3-day old rats, however, did not respond with induction of HSP 70. In contrast we could detect inducible HSP 70 in islets from 3-day old diabetes-resistant LEW rats. In islets from 90-day old BB rats we observed a decreased amount of HSP 70 compared with islets from 9-, 12-, 30- and 60-day old animals. There was also a higher extent of HSP 70 to observe in islets from 90-day old LEW rats as compared with 90-day old BB rats. Differences in HSP 70 expression between islets of 3-day old BB and LEW rats and other age groups of BB rats might represent distinct stages of maturation of islets whereas diminished expression of HSP 70 in islets of 90-day old BB rats at the age of high probability of developing diabetes might result from reduced ability to induce protective mechanisms.     

Stress Response of Pancreatic Islets from Diabetes Prone BB Rats of Different Age

Protective and/or repair mechanisms are thought to be activated in pancreatic beta cells in response to injury during insulitis. Manifestation of type-1 diabetes may depend on an imbalance between beta cell damage and repair. To prove this hypothesis, the ability of collagenase-isolated islets to respond to heat stress depending on the age of BB rats was investigated. The islets were exposed either to 44°C (HS) or 37°C (control) for 30 min and then kept at 37°C for 5 h. Immediately and 5 h after heat shock, insulin secretion in response to 20 mmol/l glucose and total protein synthesis of heat-exposed islets were significantly diminished as compared with controls. The islet proteins were separated by SDS-PAGE followed by immunoblotting. Islets from BB rats at an age of 6-90 days responded to heat shock with the expression of major heat shock protein 70 (HSP 70). Islets from 3-day old rats, however, did not respond with induction of HSP 70. In contrast we could detect inducible HSP 70 in islets from 3-day old diabetes-resistant LEW rats. In islets from 90-day old BB rats we observed a decreased amount of HSP 70 compared with islets from 9-, 12-, 30- and 60-day old animals. There was also a higher extent of HSP 70 to observe in islets from 90-day old LEW rats as compared with 90-day old BB rats. Differences in HSP 70 expression between islets of 3-day old BB and LEW rats and other age groups of BB rats might represent distinct stages of maturation of islets whereas diminished expression of HSP 70 in islets of 90-day old BB rats at the age of high probability of developing diabetes might result from reduced ability to induce protective mechanisms.     

Prophylactic Insulin Treatment of Syngeneically Transplanted Pre-diabetic BB-DP Rats

Type 1 Diabetes Mellitus is characterized by selective destruction of the pancreatic &#103 -cells in the islets of Langerhans and insulitis. Subcutaneous insulin injections given to diabetes prone BioBreeding (BB-DP) rats reduce diabetes incidence. The underlying mechanism(s) are not known in detail. Previously, we showed that transplantation of 200 syngeneic neonatal islets under the kidney capsule is useful for studying molecular events during diabetes development in BB-DP rats. In the present study we tested if prophylactic insulin treatment of syngeneically transplanted BB-DP rats would protect both islets in situ and transplanted islets from destruction. Methods : BB-DP rats received transplants of 200 syngeneic neonatal islets under the kidney capsule at 30 days of age. They were given a subcutaneous insulin or placebo implant and were compared to control rats. Blood glucose was measured three times weekly. In total, 193 rats were transplanted and rats were sacrificed 7, 23, 50, 90 days post-transplantation or at onset of diabetes. Pancreatic and transplant sections were stained for insulin and mononuclear cell infiltration and insulitis was graded. Results : Eight (19%) rats developed diabetes in the insulin-treated group and 19 (63%) and 19 (65%) rats in the control and placebo, respectively ( p =0.0002 and p =0.0001). Onset of diabetes in the insulin treated group was delayed compared to control and placebo, (102, 77 and 81 days of age, respectively ( p =0.0001 and p =0.0001 )). Insulin treatment diminished mononuclear cell infiltration in the islets at day 50 after transplantation compared to placebo. Infiltration pattern in islets in situ correlates with infiltration in transplants ( r is 0.9076 and p <0.001). Conclusion/interpretation : These results suggest that insulin-treatment of syngeneically transplanted BB-DP rats considerably decreases the incidence of diabetes and that this model is well suited for studying molecular changes in the islet transplants.     

替米沙坦通过抑制胰岛内质网应激减少STZ致长期高脂喂养大鼠糖尿病的发生

目的:研究肾素血管紧张素Ⅱ受体阻断剂替米沙坦对长期高脂喂养大鼠链脲佐菌素(STZ)致糖尿病的发病率和胰岛β细胞功能的影响及其作用机制。方法:以高脂高热量饮食饲养Wistar大鼠,16周后以替米沙坦干预,24周后1次性给予小剂量STZ,注射STZ1周后行静脉胰岛素释放实验检测胰岛β细胞功能;采用反转录-聚合酶链反应及免疫组化法检测胰岛内质网应激因子及胰岛素的表达。结果:与高脂+STZ组相比,高脂+替米沙坦+STZ组大鼠糖尿病发病率明显下降,胰岛素最大分泌量增加了56.9%,早期胰岛素分泌指数(EISI)及急性胰岛素分泌反应(AIR)升高了1.98倍和0.88倍,β细胞内胰岛素表达量及胰岛素阳性表达细胞密度明显增加,胰岛β细胞内质网应激凋亡相关分子免疫球蛋白结合蛋白、C/EBP同源蛋白基因表达及Bax蛋白表达均显著下降。结论:肾素血管紧张素系统(RAS)阻断可以增强长期高脂喂养大鼠对STZ性糖尿病的抵抗性,减少β细胞内质网应激介导的凋亡因子的表达。减弱胰岛内质网应激可能是RAS阻断而改善β细胞功能、减少糖尿病发生的重要机制之一。     

The pancreatic β-cell in ageing: Implications in age-related diabetes

The prevalence of type 2 diabetes (T2D) and impaired glucose tolerance (IGT) increases with ageing. T2D generally results from progressive impairment of the pancreatic islets to adapt β-cell mass and function in the setting of insulin resistance and increased insulin demand. Several studies have shown an age-related decline in peripheral insulin sensitivity. However, a precise understanding of the pancreatic β-cell response in ageing is still lacking. In this review, we summarize the age-related alterations, adaptations and/or failures of β-cells at the molecular, morphological and functional levels in mouse and human. Age-associated alterations include processes such as β-cell proliferation, apoptosis and cell identity that can influence β-cell mass. Age-related changes also affect β-cell function at distinct steps including electrical activity, Ca²⁺ signaling and insulin secretion, among others. We will consider the potential impact of these alterations and those mediated by senescence pathways on β-cells and their implications in age-related T2D. Finally, given the great diversity of results in the field of β-cell ageing, we will discuss the sources of this heterogeneity. A better understanding of β-cell biology during ageing, particularly at older ages, will improve our insight into the contribution of β-cells to age-associated T2D and may boost new therapeutic strategies.     

Endocrine Pancreas Histology of Congenic BB-Rat Strains with Reduced Diabetes Incidence After Genetic Manipulation on Chromosomes 4, 6 and X

Congenic BB.SHR rat strains were established by crossing of spontaneously diabetic BB/OK rats and diabetes-resistant SHR rats. Chromosomal regions on which the genes Iddm 4 (BB.6s), Iddm6 (BB.Xs) and Iddm 2 (BB.LL) are located were exchanged. As a result of genetic manipulation diabetes incidence was markedly reduced from 80% in BB/OK to 50% in BB.SHR (Chr. X), to 14% in BB.SHR (Chr. 6) and to 0% in BB.LL rats. Pancreata of these newly generated BB.SHR rats were investigated histologically. In newly diagnosed diabetic rats of congenic strains pancreatic insulin content (BB.6s: p<0.05; BB.Xs p<0.01) and relative volume of insulin-positive cells (BB.Xs: p<0.001) were significantly higher than in BB/OK rats. The degree of insulitis was not different in 90-day-old and newly diagnosed diabetic animals. Surprisingly, in 30-day-old rats we observed an increase of the degree of insulitis with decreasing diabetes incidence. We suppose that by an earlier occurrence of the immunological β-cell destruction, a part of the animals is able to develop a secondary diabetes resistance. The exchange of the BB-lymphopenia gene by that of SHR-rats prevented the development of hyperglycaemia without altering the auto-reactive immune response, which could be observed in all animals investigated.     

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

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 within grafts derived from donors of incompatible MHC.     

Dynamic time course studies of the spontaneously diabetic BB Wistar rat. III. Light-microscopic and ultrastructural observations of pancreatic islets of Langerhans.

The pancreatic islet alterations were studied in spontaneously diabetic BB Wistar rats and in young (50 and 65 days old) normoglycemic BB rats with the use of light microscopy, immunohistochemistry, and electron microscopy. Three groups of diabetic rats were delineated: 1) early diabetes (1-3 days after detection of glycosuria), 2) stable diabetes (41-63 days after detection), and 3) unstable diabetes (7-22 days after detection). In early diabetes islets were extensively infiltrated by "activated" lymphocytes and macrophages, and B cells demonstrated marked degranulation, injury, and necrosis. Although no consistent changes were recorded in A cells, D cells appeared to be decreased in number. In stable and unstable diabetes, islets were small and markedly depleted of B cells, although more insulin-containing cells were identified in the stable group. The number of A and D cells appeared normal in the stable group, although some A cells appeared altered ultrastructurally. In the unstable group both A and D cells appeared decreased, and ultrastructurally altered A cells were again noted. These findings suggest that although B cells appear to be the principal islet target in this model, A and D cells also sustain cellular injury. Variable degrees of insulitis, B cell degranulation, and necrosis were documented in 65-day-old normoglycemic BB rats, suggesting that the destructive process in the islets is initiated well in advance of the onset of the clinical syndrome. The pancreases from many diabetic and normoglycemic BB rats also demonstrated mononuclear cell infiltrates distinct from insulitis in periductular and/or acinar locations. These infiltrates, not present in controls, appear to represent an additional morphologic expression of the process responsible for initiating the diabetic state.     

Diabetes mellitus in the BB/W rat. Insulitis in pancreatic islet grafts after transplantation in diabetic recipients.

Spontaneous diabetes mellitus in the BioBreeding/Worcester (BB/W) rat is preceded by lymphocytic insulitis which destroys pancreatic beta cells. Cultured major histocompatibility complex identical pancreatic islets and adrenal cortex derived from diabetes-resistant BB/W donors were transplanted into diabetic recipients with hyperglycemia of variable duration. Islet grafts were the targets of BB/W immune attack and revealed lymphocytic insulitis after transplantation into diabetic recipients even in the absence of insulitis within endogenous pancreatic islets. These findings suggest that the BB/W immune attack on pancreatic beta cells can recur in islet grafts long after the onset of the diabetic syndrome.     

Decreased β-cell insulin secretory function in aged rats due to impaired Ca2+ handling

Ageing is associated with an increased impairment in glucose homeostasis and an increased incidence of type?2 diabetes. In this study, we evaluated β-cell function and its implications for glucose homeostasis in 24-month-old female Wistar rats. Aged rats showed lower plasma glucose levels in the fed and fasting states compared with control rats. In addition, insulinaemia in the fed state was reduced in the older rats. Insulin receptor?β (IRβ) expression was lower in the livers of the aged animals, whereas IRβ and Akt(1/2/3) protein expressions were higher in the muscles. These effects may contribute to the normal glucose tolerance observed in older rodents. Isolated islets from aged rats secreted less insulin in response to 8.3 and 16.7?mm glucose. Accordingly, this group presented a lower [Ca(2+)](i) in the presence of glucose and a depolarizing stimulus (30?mm K(+)). In addition, islets from aged rats showed reduced insulin secretion in response to 100?μm carbachol (CCh), 10?nm phorbol 12-myristate 13-acetate and 10?μm forskolin. The expressions of protein kinase?C, protein kinase?A and exocytotic proteins, such as syntaxin?1 and synaptosomal-associated protein 25?kDa (SNAP-25), were similar in islets from aged and control rats. In conclusion, our evidence suggests that the increased incidence of type?2 diabetes with age may be due to a progressive decline in β-cell secretory capacity due to disruption of Ca(2+) handling. Furthermore, the expression of proteins of the insulin transduction cascade showed an adaptive profile, with a compensatory increase in IRβ and Akt(1/2/3) in gastrocnemius muscles, which may maintain normal glucose homeostasis in 24-month-old rats.     

The time course of insulin autoantibodies (IAA) in the diabetes prone BB rat

The BB rat is a widely used animal model for the study of insulin dependent diabetes. An enzyme linked immunosorbent assay, using purified rat insulin, was used to measure serial insulin autoantibodies (IAA) levels in coded sera from the BB/W/D rat colony in order to establish the time course of IAA. The animals included 26 diabetes-prone BB rats, six diabetes-resistant BB rats and six Wistar controls. There was an increase in both IAA frequency and titre with time in the diabetes-prone group: none were positive at 45 days, 17/19 (89%) were positive by day 90 and all were positive thereafter. Similar results were observed in the diabetes-resistant BB group (0/6 positive at day 51, 6/6 positive at day 90). None of the Wistar controls were positive at 105 days, although occasional positive sera were observed at 120 days. IAA seem to be acquired early on in the majority of BB rats, both diabetes-prone and diabetes-resistant, and much later, if at all, in controls. A clear homology of the MHC genes exists in both BB rat sublines, thus IAA appear to be a strain related phenomenon rather than a marker for IDDM.     

Prediction of diabetes in Biobreeding/Aburahi rats by the measurement of soluble L-selectin

L-selectin was initially identified as a homing receptor, recently soluble L-selectin has been used as a marker of the inflammation. Therefore, we investigated the relation between the development of diabetes and serum L-selectin levels in the Biobreeding (BB) rats. Serum L-selectin were measured from 30 days old to the onset of diabetes or to 90 days old in Biobreeding (BB) rats and Wistar Furth (WF) rats. Significant elevation of L-selectin was found in diabetes prone (DP) rats from 45 days old to the onset of diabetes or through 90 days old. No elevation was found in other strain of rats. In histological study, all of DP rats had insulitis and no other strain of rats had it. Therefore, we conclude that the measurement of serum L-selectin could be useful tool to predict the onset of diabetes or presence of insulitis in BB rats.     

Prediction of Diabetes in Biobreeding/Aburahi Rats by the Measurement of Soluble L-Selectin

L-selectin was initially identified as a homing receptor, recently soluble L-selectin has been used as a marker of the inflammation. Therefore, we investigated the relation between the development of diabetes and serum L-selectin levels in the Biobreeding (BB) rats. Serum L-selectin were measured from 30 days old to the onset of diabetes or to 90 days old in Biobreeding (BB) rats and Wistar Furth (WF) rats. Significant elevation of L-selectin was found in diabetes prone (DP) rats from 45 days old to the onset of diabetes or through 90 days old. No elevation was found in other strain of rats. In histological study, all of DP rats had insulitis and no other strain of rats had it. Therefore, we conclude that the measurement of serum L-selectin could be useful tool to predict the onset of diabetes or presence of insulitis in BB rats     

BETA-CELL APOPTOSIS IS RESPONSIBLE FOR THE DEVELOPMENT OF IDDM IN THE MULTIPLE LOW-DOSE STREPTOZOTOCIN MODEL

Although insulin-dependent diabetes mellitus (IDDM) results from irreversible loss of beta cells, the mode of cell death responsible for this loss has not previously been categorized. In this study, the multiple low-dose streptozotocin (stz) model (intraperitoneal injection of stz at a concentration of 40 mg/kg body weight per day for five consecutive days) was used to investigate beta-cell death during the development of IDDM in male C57B1/6 mice. Apoptotic cells were evident by light microscopy within the islets of Langerhans of treated animals from day 2 (the day of the second stz injection) until day 17. Immunohistochemical localization of insulin to the dying cells confirmed the beta-cell origin of the apoptosis. Two peaks in the incidence of beta-cell apoptosis occurred: the first at day 5, which corresponded to an increase in blood glucose concentration, and the second at day 11, when lymphocytic infiltration of the islets (insulitis) was maximal. Insulitis did not begin until day 9, by which time treated animals had developed overt diabetes as revealed by blood glucose and pancreatic immunoreactive insulin (IRI) measurements. Beta-cell apoptosis preceded the appearance of T-cells in the islets and continued throughout the period of insulitis. Thus, whether induced by stz or a subsequent immune response, apoptosis is the mode of cell death responsible for beta-cell loss in the multiple low-dose stz model of IDDM.     

Prophylactic insulin treatment of syngeneically transplanted pre-diabetic BB-DP rats

Type 1 Diabetes Mellitus is characterized by selective destruction of the pancreatic beta-cells in the islets of Langerhans and insulitis. Subcutaneous insulin injections given to diabetes prone BioBreeding (BB-DP) rats reduce diabetes incidence. The underlying mechanism(s) are not known in detail. Previously, we showed that transplantation of 200 syngeneic neonatal islets under the kidney capsule is useful for studying molecular events during diabetes development in BB-DP rats. In the present study we tested if prophylactic insulin treatment of syngeneically transplanted BB-DP rats would protect both islets in situ and transplanted islets from destruction. METHODS: BB-DP rats received transplants of 200 syngeneic neonatal islets under the kidney capsule at 30 days of age. They were given a subcutaneous insulin or placebo implant and were compared to control rats. Blood glucose was measured three times weekly. In total, 193 rats were transplanted and rats were sacrificed 7, 23, 50, 90 days post-transplantation or at onset of diabetes. Pancreatic and transplant sections were stained for insulin and mononuclear cell infiltration and insulitis was graded. RESULTS: Eight (19%) rats developed diabetes in the insulin-treated group and 19 (63%) and 19 (65%) rats in the control and placebo, respectively (p = 0.0002 and p = 0.0001). Onset of diabetes in the insulin treated group was delayed compared to control and placebo, (102, 77 and 81 days of age, respectively (p = 0.0001 and p = 0.0001)). Insulin treatment diminished mononuclear cell infiltration in the islets at day 50 after transplantation compared to placebo. Infiltration pattern in islets in situ correlates with infiltration in transplants (r is 0.9076 and p < 0.001). CONCLUSION/INTERPRETATION: These results suggest that insulin-treatment of syngeneically transplanted BB-DP rats considerably decreases the incidence of diabetes and that this model is well suited for studying molecular changes in the islet transplants.     

β-cell loss and β-cell apoptosis in human type 2 diabetes are related to islet amyloid deposition

Amyloid deposition and reduced β-cell mass are pathological hallmarks of the pancreatic islet in type 2 diabetes; however, whether the extent of amyloid deposition is associated with decreased β-cell mass is debated. We investigated the possible relationship and, for the first time, determined whether increased islet amyloid and/or decreased β-cell area quantified on histological sections is correlated with increased β-cell apoptosis. Formalin-fixed, paraffin-embedded human pancreas sections from subjects with (n = 29) and without (n = 39) diabetes were obtained at autopsy (64 ± 2 and 70 ± 4 islets/subject, respectively). Amyloid and β cells were visualized by thioflavin S and insulin immunolabeling. Apoptotic β cells were detected by colabeling for insulin and by TUNEL. Diabetes was associated with increased amyloid deposition, decreased β-cell area, and increased β-cell apoptosis, as expected. There was a strong inverse correlation between β-cell area and amyloid deposition (r = -0.42, P < 0.001). β-Cell area was selectively reduced in individual amyloid-containing islets from diabetic subjects, compared with control subjects, but amyloid-free islets had β-cell area equivalent to islets from control subjects. Increased amyloid deposition was associated with β-cell apoptosis (r = 0.56, P < 0.01). Thus, islet amyloid is associated with decreased β-cell area and increased β-cell apoptosis, suggesting that islet amyloid deposition contributes to the decreased β-cell mass that characterizes type 2 diabetes.     

The relationship between insulin autoantibodies and islet cell histology in the diabetes prone BB rat.

The relationship between insulin autoantibodies (IAA) and pancreatic islet cell histology was examined in 71 diabetes prone BB rats from the Toronto colony. Twenty-seven of the 71 became diabetic and of these, 18 (67%) were IAA positive by ELISA. IAA were also detected in 39/44 (89%) which did not develop diabetes, but in none of six control animals at 50-140 days of age. All 27 which became diabetic showed some evidence of lymphocytic infiltration scored + to ++++ histometrically and 26/27 evidence of beta cell degranulation. The frequency of diabetes increased with both intensity of insulitis and degree of beta cell degranulation, but there was no correlation between either and IAA. IAA are a marker for the BB strain of Wistar rat, but do not correlate with islet cell histology and do not predict clinical diabetes.     

AEB-071 has minimal impact on onset of autoimmune diabetes in NOD mice

Protein kinase C (PKC) is an important signaling enzyme in the activation and regulation of T lymphocytes. T-cell-mediated destruction of β-cells is a characteristic feature of autoimmune (Type 1) diabetes. Here we explore the ability of PKC inhibition, using the PKC inhibitor AEB-071 (AEB), to reduce disease in two animal models of spontaneous autoimmune diabetes (non-obese diabetic (NOD) mouse and biobreeding rat (BB)). NOD mice were treated with AEB for 4 weeks, starting at either 4 weeks of age (prior to the development of insulitis) or at 8 weeks of age, once insulitis is present. Animals treated with AEB during the effector phase of the disease (treatment onset at 8 weeks of age), showed a 2-week delay in diabetes onset (p < 0.05). In these animals, the extent of insulitis was lower than in vehicle-treated controls; however, neither serum autoimmune anti-GAD65 antibody levels nor pancreatic insulin content were different between experimental groups. Overall, inhibition of PKC can mildly reduce lymphocytic infiltrate of pancreatic islets and modestly delay onset of autoimmune diabetes in NOD mice. AEB, a T-cell-targeted immunosuppressive strategy, is only sufficient as a monothereapy to modestly delay onset of autoimmune disease in the NOD mouse.