Pancreas Fat and β Cell Mass in Humans With and Without Diabetes: An Analysis in the Japanese Population

Context: The mechanisms by which beta cell mass is reduced in patients with type 2 diabetes remain unclear. It has been postulated that ectopic fat deposits in the pancreas induce beta cell apoptosis, leading to the development of diabetes. Objective: The aim of this study was to clarify the effects of intrapancreatic fat on beta and alpha cell mass in humans with and without diabetes. Design and Subjects: Using our tissue database, pancreas sections of 72 Japanese nondiabetic (NDM) autopsy cases and 50 diabetic and 49 age-and body mass index (BMI)-matched NDM patients who underwent pancreatic surgery were analyzed. In addition to histological grading, intrapancreatic fat area (IPFA) was quantified as fractional intralobular, but not interlobular, fat area to the whole pancreas area. Results: Although IPFA was positively correlated with age and BMI, there was no significant difference in IPFA between cases with and without diabetes. Moreover, no association was found between IPFA and either beta or alpha cell area, or glycated hemoglobin. Conclusion: These findings suggest that pancreatic fat deposits have little effect on beta cell mass and the development of diabetes in humans.