Role of hyperglycemia in isogeneic islet transplantation: an experimental animal study.

OBJECTIVE Study the role of hyperglycemia-induced beta cell loss on grafted islet destruction. DESIGN Male inbred rats were made diabetic by streptozotocin administration and used as islet donors and/or isograft recipients to probe directly the role of hyperglycemia as an important determinant of transplanted islet fate, following exclusion of immune-related causes of islet graft destruction like allograft immunity and disease recurrence. RESULTS Our studies showed that: a) Hyperglycemia destroyed islet but not pituitary isografts and b) Tight control of normoglycemia by sufficient islet mass engraftment prevented graft damage. CONCLUSION While sustained hyperglycemia caused destruction of transplanted islet isografts, induction of normoglycemia by transplantation of sufficient islet mass to diabetic recipients had a beneficial long term effect on their functional engraftment.