NORMALIZATION OF DIABETES IN SPONTANEOUSLY DIABETIC CYNOMOLOGUS MONKEYS BY XENOGRAFTS OF MICROENCAPSULATED PORCINE ISLETS WITHOUT IMMUNOSUPPRESSION

Porcine pancreatic islets were microencapsulated in alginate-polylysin e-alginate capsules and transplanted intraperitoneally into nine spont aneously diabetic monkeys. After one, two, or three transplants of 3-7 x 10(4) islets per recipient, seven of the monkeys became insulin ind ependent for periods ranging from 120 to 804 d with fasting blood gluc ose levels in the normoglycemic range. Glucose clearance rates in the transplant recipients were significantly higher than before the graft administration and the insulin secretion during glucose tolerance test s was significantly higher compared with pretransplant tests. Porcine C-peptide was detected in all transplant recipients throughout their p eriod of normoglycemia while none was found before the graft administr ation. Hemoglobin A(1C) levels dropped significantly within 2 mo after transplantation. While ketones were detected in the urine of all reci pients before the graft administration, all experimental animals becam e ketone free 2 wk after transplantation. Capsules recovered from two recipients 3 mo after the restoration of normoglycemia were found phys ically intact with enclosed islets clearly visible. The capsules were free of cellular overgrowth. Examination of internal organs of two of the animals involved in our transplantation studies for the duration o f 2 yr revealed no untoward effect of the extended presence of the mic rocapsules.