Cells Persist in T 1 D Pancreata Without Evidence of Ongoing b-Cell Turnover or Neogenesis

Results: Residual insulin-producing b cells were detected in some (but not all) T1D cases of varying disease duration. Several T1D pancreata had substantial numbers of b cells. Although b-cell proliferation was prominent early in life, it dramatically declined after infancy in both nondiabetic controls andT1D individuals. However,b-cell proliferationwasequivalent in control andT1Dpancreata. b-cell death (assessed by TUNEL) was extremely rare in control and T1D pancreata. Thus, b-cell turnover was not increased in T1D. Furthermore, we found no evidence of small islet/ductal neogenesis or a-cell to b-cell transdifferentiation in T1D pancreata, regardless of disease duration.