Residual Insulin Production and Pancreatic β-Cell Turnover After 50 Years of Diabetes: Joslin Medalist Study

Histologic findings in pancreases from nine Medalists. In seven of nine pancreases, there were mainly atrophic islets (A) in which all or almost all cells were immunostained for glucagon, with occasional small islets that had peripheral glucagon+ cells with unstained central cells (asterisks), and rare small clusters or scattered single insulin+ cells (B); all nine pancreases had these scattered insulin+ cells. In one antibody-positive Medalist, some insulin+ cells were TUNEL-positive (B). In another pancreas (from Medalist 8) (C–F), about half of the pancreas had only atrophic islets (C), although there were lobes within the body and tail of the pancreas, with most islets with significant proportion of insulin+ cells (D and E, adjacent sections) and some with amyloid deposits (F) (thioflavin S+). In another late-onset diabetes pancreas (Medalist 9; age 30 at onset) (G–I), every islet had at least one insulin+ cell, and most had 10–20% of normal (G). In this last Medalist pancreas, rare Ki67+insulin+ cells (arrows indicate Ki67+ nuclei, both within the islet and nearby) (H) were found. I: In three pancreases, CD3 cells were rarely found in insulin+ islets, whereas no other CD3 cells were found in the microscopic field. (A high-quality digital representation of this figure is available in the online issue.)