Glomerular ultrastructure in kidneys transplanted simultaneously with a segmental pancreas to patients with type 1 diabetes.

BACKGROUND

Pancreas transplantation has been reported to prevent development and progression of diabetic glomerulopathy.

STUDY DESIGN

Kidneys transplanted to type 1 diabetic patients were investigated for signs of diabetic glomerulopathy. Biopsies were obtained from 11 patients 2-4 years after simultaneous pancreas and kidney transplantation and from six patients 2-6 years after kidney transplantation alone. During follow-up, glycaemic control was monitored as glycated haemoglobin and, in the pancreas transplant patients, as i.v. glucose tolerance.

RESULTS

Measures of glycaemic control were consistently normal in only two pancreas transplant patients. Four had mean k values <1.0. In kidney biopsies from the pancreas transplant patients, thickness of the glomerular basement membrane was 395 (0.13) nm (mean, coefficient of variation), which is higher than normal (324 (0.13) nm, P=0.01) and not different from diabetic patients with kidney transplants alone, 418 (0.15) nm. The mean calculated annual increase in thickness did not differ between patients with and without a pancreas transplant, 26 (0.77) versus 29 (0.54) nm/year. Estimates of the mesangium and mesangial matrix were in the normal range in both groups while the interstitial volume fraction was increased and to a similar extent.

CONCLUSION

The increase in thickness of the glomerular basement membrane in kidneys transplanted simultaneously with a segmental pancreas is probably an expression of diabetic glomerulopathy caused by the modest impairment in glucose metabolism present in most patients.