Islet amyloid polypeptide in pancreatic islets from type 2 diabetic subjects

Abstract

Keywords: amyloid deposit, islet amyloid polypeptide, immunocytochemistry, pancreatic islets, type 2 diabetes to unfold disappearing water-soluble IAPP in secretary granules from dying β-cells to refold water-insoluble polymerized amyloid fibrils in transforming β-sheet conformation in IAPP-containing islet deposits 8,14-17 by immunocytochemical staining using different dilutions of rabbit antihuman IAPP antibody. Results Control islets.The mean islet cell numbers of extra-large, large and medium-sized islets were 120, 71 and 34 cells, respectively, representing 8, 44 and 48% in a total of 225 islets examined for nine age-matched control cases ( Table 1). The relative percentages of β-cells for insulin, α-cells for glucagon and δ-cells for somatostatin (SARIF) were about 60, 30 and 15% respectively, among all three sizes of islets (Table 1). By immunocytochemical staining, all three pancreatic hormone and IAPP staining was granular in the cytoplasm, in which insulin and IAPP staining was of variable staining intensity from moderately to strongly

Tumor-Associated Lymphatic and Venous Vessels in Medullary Thyroid Carcinomas

“…The morphologic appearance of these intratumoral lymphatic vessels resembles that of immature tumor venous vessels observed in other tissues [16]. There were similarly irregular lymphatic vessels in peritumoral tissues in MTCs, which match well with the newly formed, entrapped lymphatic vessels in the advancing margins of the tumor, resembling that of immature tumor blood vessels observed in the advancing margins of colonic carcinomas [17]- [20].…”

“…For evaluating LYVE-1 and F-8 immunostaining, morphometric analysis was performed using a mounted 1 cm linear scale with 10 µm intervals in the 10X eye piece. The length and width of LYVE-1 positive lymphatic vessels and F-8 positive venous vessels were measured in µm at 10 × 10 = 100× magnification as reported previously [16]. Both lymphatic and venous vessels were measured in the ten 100× fields for peri-and intra-tumor lesions and for non-tumor lesions, the latter was >1 cm away from the MTCs.…”

Geniposide protects pancreatic INS‐1E β cells from hIAPP‐induced cell damage: Potential involvement of insulin degrading‐enzyme

“…IDE is the key enzyme responsible for the intracellular degradation of hIAPP (Zraika et al, ). Although the primary function of IDE in mammalian tissues has traditionally been thought to degrade insulin, a number of other proteins have been identified as substrates of IDE, such as proinsulin, IGF‐II, relaxin, glucagon, Aβ and hIAPP (Tomita, ). Radio‐labeled hIAPP covalently cross‐linked to IDE in cell‐free extracts and also a monoclonal antibody directed against IDE immunoprecipitated both insulin and hIAPP, confirming that IDE is the hIAPP‐degrading protease (Zraika et al, ).…”

“…The first report on amyloid deposits in pancreatic islets of a diabetic subject was made over one hundred years ago. It is predicted that >300 million individuals worldwide will be affected by 2,025 (Tomita, ). Extensive IAPP deposits are thought to contribute to pancreatic β cell dysfunction, either by direct cytotoxicity or by reducing β cell mass resulting in impaired insulin secretion (Haataja et al, ).…”

1, 25(OH)2D3 protects β cell against high glucose-induced apoptosis through mTOR suppressing

“…Aside from the possible genetic and epigenetic factors 14 , researches revealed that multiple mechanisms may be involved in the β-cell apoptosis process 15 , including cytokines 16 , higher workload maintaining normal glycemia 17 , endoplasmic reticulum stress (ERS) 18 , elevated free fatty acid levels 19 , and accumulation of amyloids in pancreatic islets 20 . Medications that can inhibit β-cell apoptosis obviously prevent further reduction of β-cell mass, and thus become the potential treatment for diabetes.…”