BETA-CELL FUNCTION ABNORMALITIES IN ISLETS FROM AN ADULT SUBJECT WITHNESIDIOBLASTOSIS AND AUTOANTIBODIES AGAINST THE ISLET CELLS

Human islets from an adult subject with nesidioblastosis were isolated and used to perform in vitro studies. Isolated nesidioblastotic islet s showed an increased basal rate of insulin secretion (nesidioblastoti c islets, 81.3 +/- 6.4 vs. control islets, from cadaveric organ normal donors, 10.2 +/- 0.9 mu U/islet/90 min) without any further release w ith increasing glucose concentration. In addition, islets isolated fro m the pancreas with nesidioblastosis contained more insulin than contr ol islets, 1,547.0 +/- 128.7 vs. 935.0 +/- 51.7 mu U/islet, and the le vels of insulin mRNA were also higher than those measured in controls. Interestingly, the serum of the subject with nesidioblastosis contain ed autoantibodies that stained brightly and selectively a population o f islet cells whose distribution coincided with that expected of alpha cells. In summary, pancreatic islets in nesidioblastosis display beta -cell functional abnormalities. Moreover, the finding of antibodies ag ainst islet cells is a common feature in the serum of nesidioblastotic subjects; nevertheless, their pathological significance warrants furt her investigation.