Pancreas Atrophy and Islet Amyloid Deposition in Patients With Elderly-Onset Type 2 Diabetes

Context: With prolonged life expectancy, we often encounter patients with elderly-onset type 2 diabetes mellitus (eT2DM). Although the clinical features of eT2DM are suggested to be different from those in patients with middle-age-onset type 2 diabetes mellitus (mT2DM), the islet pathologic features in eT2DM have not been addressed. Objective: We attempted to characterize the pancreatic pathology in eT2DM and sought its clinical implications. Materials and Methods: Pancreata from 13 young nondiabetic (age, 20 to 29 years), 27 patients with mT2DM(age, 45 to 87 years), 22 middle-age subjects without T2DM, 15 subjects with eT2DM (age, 85 to 100 years), and 30 elderly subjects without T2DM were investigated. Together with conventional microscopic observations, morphometric analysis on the islet, islet endocrine cells, and amyloid deposition was conducted on immunostained sections. Results: The estimated age of diabetes onset was 80.8 +/- 1.4 years (mean +/- standard error) in the eT2DM group and that of the mT2DM group was 48.3 +/- 2.4 years. The pancreatic weight was nearly 50% less in the eT2DM group than in the other groups, showing duct obstruction with epithelial hyperplasia, marked acinar atrophy, fibrosis, and amyloid deposition in the islet. The islet mass was significantly reduced in the eT2DM group. The amyloid volume density correlated inversely with the beta-cell volume density but not with the body mass index in the eT2DM group. Laboratory data showed mild elevation of serum amylase in the eT2DM group, although clinical signs and symptoms of pancreatitis were not apparent. Conclusions: eT2DM is distinct from mT2DM and characterized by pancreas atrophy, ductal lesions, and amyloid deposition.