Islet implantation normalises hyperglycaemia caused by streptozotocin-induced insulitis. Experiments in mice

Islet-cell deterioration in juvenile diabetes mellitus may be due to an autoimmune reaction, possibly involving both circulating islet-cell antibodies and an inflammatory process in the islets of Langerhans. Replacement of deteriorated islet cells by implantation of normal ones is now under investigation in many laboratories. The present study does not support the assumption that such islet transplants should be affected in the same way as the endogenous islets. Diabetic mice with a cell-mediated immune reaction to their pancreatic islets, induced by repeated injections of low doses of streptozotocin, were used as recipients. Isogeneic islets implanted intrasplenically in these animals were as effective in producing normoglycaemia as were those injected into animals made diabetic with a single bolus dose of streptozotocin. No inflammatory reaction was seen in the implanted islets, irrespective of the regimen of the preceding streptozotocin treatment. This finding suggests that islet-cell implantation may be attempted in insulin-requiring diabetic patients, even if the cause of the disorder is an inflammatory lesion of the patient's own islets.