Effect of pancreas transplantation on diabetic somatic neuropathy.

To determine whether pancreas transplantation is capable of preventing diabetic somatic neuropathy, metabolic studies and electron microscopic morphometry of the sciatic nerve were performed monthly for 2 years in four groups of highly inbred rats: (1) NC-28 nondiabetic controls; (2) DC-82 untreated alloxan-diabetic controls; (3) WPT-122 diabetic rats that received a syngeneic whole-pancreas transplant; and (4) IT-90 diabetic rats that received intraportal injections of 1500 to 2000 syngeneic pancreatic islets. Five diabetic nerve lesions were quantitated by a "blind" protocol: intra-axonal glycogen deposits, axons with glycogen deposits, demyelinated axons, intact axoglial junctions in paranodal terminal myelin loops, and basal lamina thickness of vasa nervorum. Untreated diabetic control animals had significant and progressive increases in all five nerve lesions compared to nondiabetic controls (p less than 0.01). Whole pancreas transplants produced precise metabolic control of diabetes and prevented development and progression of all five diabetic nerve lesions throughout the 2-year study period. Pancreatic islet transplantation produced strict metabolic control and prevented diabetic neuropathy for the first 6 months, but then diabetes recurred and nerve lesions that were similar in severity to those in untreated diabetic rats developed. The finding that whole pancreas transplantation prevents diabetic somatic neuropathy adds to and extends our previous studies showing that whole-pancreas transplants prevent diabetic nephropathy.