Makoto Moriwaki

Fas and Fas ligand expression in inflamed islets in pancreas sections of patients with recent-onset Type I diabetes mellitus.

Aims/hypothesis. Type I (insulin-dependent) diabetes results mainly from T-cell-mediated autoimmune destruction of pancreatic beta cells. Cytotoxic T lymphocytes destroy target cells via a perforin-based or Fas-based mechanism. Our previous study indicated that the Fas-Fas ligand (FasL) pathway is required for the development of autoimmune diabetes in the NOD mouse. We now investigated whether or not the Fas-FasL system is involved in the beta-cell destruction in human Type I diabetes. Methods. We immunohistochemically analysed pancreas biopsy specimens of 13 recent-onset patients. Results. Pancreatic islets were identified but showed various degrees of reduction in beta-cell volume in all patients. Out of 13 patients 6 had insulitis. In these 6 patients Fas was expressed in both the islets and infiltrating cells but not in either cell type in the 7 other patients without insulitis. Double immunostaining showed that Fas was positive in 92.2 to 97.7 % of beta cells but only in 17.6 to 46.7 % of alpha cells in Fas-positive, insulin-remaining islets. We found FasL was expressed exclusively in islet-infiltrating cells in patients with insulitis. Double immunostaining revealed that the most prevalent phenotype of FasL-positive cells was CD8, which was followed by macrophages and CD4. Conclusion/interpretation. The interaction between Fas on beta cells and FasL on infiltrating cells might trigger selective apoptotic beta-cell death in inflamed islets, leading to immune-mediated Type I diabetes. [Diabetologia (1999) 42: 1332–1340]

Macrophages and dendritic cells infiltrating islets with or without beta cells produce tumour necrosis factor-α in patients with recent-onset type 1 diabetes

Aims/hypothesisType 1A diabetes results from autoimmune destruction of pancreatic beta cells. We examined the involvement of TNF-α and IL-1β, as well as of T cells, macrophages and dendritic cells, in the destruction of beta cells in patients with recent-onset type 1 diabetes.Materials and methodsWe obtained pancreatic biopsy specimens from six patients with recent-onset type 1 diabetes and analysed these by immunohistochemistry.ResultsT cell infiltration was less common in islets without beta cells (12.5 [0–33.3]%) than in those with beta cells (46.0 [17.4–83.3]%), while macrophages and dendritic cells showed a similar extent of infiltration into islets both with or without beta cells. TNF-α was detected in 25.0 (4.3–46.9)% of macrophages and 11.8 (0–40.0)% of dendritic cells infiltrating the islets in samples from each patient, but not at all in T cells. IL-1β was detected in 1.8 (0–11.3)% of T cells infiltrating the islets with beta cells, while it was found in 19.2 (0–35.3)% of macrophages or 10.7 (0–31.3)% of dendritic cells infiltrating the islets in samples from each patient (all values median [range]).Conclusions/interpretationMacrophages and dendritic cells infiltrate the islets and produce inflammatory cytokines (TNF-α and IL-1β) during the development of type 1A diabetes.

Immunological abnormalities in islets at diagnosis paralleled further deterioration of glycaemic control in patients with recent-onset Type I (insulin-dependent) diabetes mellitus

Aims/hypothesis. To determine whether the clinical heterogeneity observed in the development of Type I (insulin-dependent) diabetes mellitus correlates with immunohistochemical differences observed at diagnosis. Methods. Patients (n = 17) with recent-onset diabetes clinically considered to be insulin dependent (Type I), underwent pancreatic biopsy for immunohistological analysis. These patients were divided into two groups based on the presence or absence of islet immunological abnormalities (insulitis or hyperexpression of MHC class I antigens or both). The patients were also HLA typed and tested for islet cell antibodies and antibodies to glutamic acid decarboxylase (GAD-Ab). All patients were followed monthly for 2 years and their fasting plasma glucose, haemoglobin A1C and daily insulin doses were recorded. The clinical course of patients with islet immunological abnormalities was compared with that of patients without those abnormalities. Results. Patients with and without islet immunological abnormalities did not differ with regard to HLA type or islet cell antibodies. Antibodies to glutamic acid decarboxylase correlated with the presence of insulitis and MHC class I hyperexpression. These local immunological abnormalities were also associated with higher haemoglobin A1C values (p < 0.05) and a trend towards greater insulin requirements. Further, patients with the islet abnormalities had higher fasting plasma glucose concentrations 2 years after the biopsy than at the time of the biopsy (p < 0.05). Conclusion/interpretation. The heterogeneous clinical course observed following diagnosis in patients with Type I diabetes correlates with islet immunological abnormalities. Insulitis and hyperexpression of MHC class I correlate with deteriorating glycaemic control. [Diabetologia (1999) 42: 574–578]

Pancreatic beta and alpha cells are both decreased in patients with fulminant type 1 diabetes: a morphometrical assessment

Aims/hypothesisWe have previously reported that fulminant type 1 diabetes is characterised by an absence of diabetes-related antibodies and a remarkably abrupt onset. However, little is known about the mechanism of beta cell destruction in this diabetes subtype, and to obtain insights into the aetiology of the disease, we investigated residual endocrine cells and the expression of Fas and Fas ligand in fulminant type 1 diabetes.MethodsResidual beta and alpha cells were morphologically assessed in pancreatic tissue obtained by biopsy from five patients with recent-onset fulminant type 1 diabetes and five patients with recent-onset typical autoimmune type 1 diabetes. In addition, the expression of Fas and Fas ligand was evaluated by immunohistochemistry.ResultsIn fulminant type 1 diabetes, beta and alpha cell areas were decreased significantly, compared with autoimmune type 1 diabetes and control subjects. In contrast, the alpha cell area was not decreased significantly in autoimmune type 1 diabetes, compared with that in control subjects. No Fas expression in islets and Fas ligand expression in CD3+ cells in the exocrine pancreas were found in the fulminant type 1 diabetic patients who underwent this evaluation.Conclusions/interpretationOur study showed that beta and alpha cells are damaged in fulminant type 1 diabetes. In addition to the lack of Fas and Fas ligand expression, the results suggest that the mechanism of beta cell destruction in fulminant type 1 diabetes is different from that in autoimmune type 1 diabetes.

Analysis of expression profiles of islet-associated transcription and growth factors during β-cell neogenesis from duct cells in partially duct-ligated mice

Introduction &bgr;-cell neogenesis from pancreatic duct cells has been reported to occur in duct-ligated rat. Nevertheless, detailed process of this phenomenon has not been clarified. Aims and Methodology To clarify the mechanism of &bgr;-cell neogenesis, a partial pancreatic duct ligation mouse model was created. Proliferation of duct cells, &bgr;-cell neogenesis, and expression of transcription factors and differentiation/growth factors were studied by immunohistochemistry, cDNA array, and RT-PCR methods. Results In the duct-ligated portion of the pancreas, newly formed islet-like cell clusters (ICCs) were observed arising from the ducts on day 7 and afterward. Transcription factors, such as pancreatic and duodenal homeobox gene-1 (PDX-1), paired box factor 6 (Pax6), islet1 and Nkx2.2-positive cells, and protein gene product 9.5 (PGP9.5) were also induced in duct lining cells. By cDNA microarray analysis, expression of insulin-like growth factor-1 (IGF-1) and transforming growth factor &bgr;1 (TGF-&bgr;1) were above control levels on day 5, and RT-PCR showed an increase from day 5 to day 28. IGF-1 and activin A–positive cells were detected in ducts. In addition, expression of betacellulin (BTC), heparin-binding epidermal growth factor–like growth factor (HB-EGF), and TGF-&agr; were also increased from day 3 or 5. Conclusion These findings suggest that &bgr;-cell or endocrine precursors are localized among duct lining cells. Induction of several islet cell–associated transcription factors and differentiation and/or growth factors may play important roles during &bgr;-cell neogenesis in this model.

Regenerative and therapeutic effects of heparin-binding epidermal growth factor-like growth factor on diabetes by gene transduction through retrograde pancreatic duct injection of adenovirus vector.

Objectives: In the adult pancreas, pre-existing β cells, stem cells, and endocrine progenitor cells residing in the duct lining are considered important sources for β-cell regeneration. A member of the epidermal growth factor (EGF) family, heparin binding (HB)-EGF, may promote this process. We examined whether HB-EGF gene transduction into duct cells could promote β-cell regeneration. Methods: We administered an HB-EGF adenovirus vector construct to male Institute of Cancer Research mice by retrograde injection through the pancreatic duct. We also performed HB-EGF gene transduction into cultured duct cells. Results: On immunohistochemical and histomorphometric analysis of the experimental group, insulin-positive cells differentiated from duct cells, and the 5-bromo-2-deoxyuridine labeling index of β cells was significantly increased. β-cell mass was also increased, and the glucose tolerance of diabetic mice was improved at 12 weeks after injection. Using cultured pancreatic duct cells, we confirmed that HB-EGF gene transduction induced both insulin gene expression and insulin production by these cells. Conclusions: These results indicate that HB-EGF gene transduction into adult pancreatic duct cells not only promotes the proliferation of pre-existing β cells but also leads to β-cell differentiation from duct cells, and the resulting increase in β-cell mass improves glucose tolerance.

Emerging therapeutic strategies in autoimmune diabetes: aetiology, prediction, prevention and cure

(1999). Emerging therapeutic strategies in autoimmune diabetes: aetiology, prediction, prevention and cure. Emerging Therapeutic Targets: Vol. 3, No. 1, pp. 177-193.