Implantable artificial capillary unit for pancreatic islet allograft and xenograft.

Implantable artificial capillary units containing approximately 1,200 allogeneic rat islets, or approximately 3,000 xenogeneic rabbit or human islets as an implantable artificial endocrine pancreas (IAEP) were implanted in streptozotocin-induced (55 mg/kg) diabetic rats. A total of 26 rats received IAEP containing allogeneic islets. Twenty were short term experiments which lasted for 12-24 h. Four recipients survived between 1-3 days and the remaining two for 4 and 11 days respectively. Five diabetic rats received IAEP containing xenogeneic islets. The four recipients of IAEP containing rabbit islets survived up to 4 days while the recipient of IAEP containing human islets survived for 8 days. Following implantation, a decrease of plasma glucose from the initial value of 500 mg/dl to normoglycaemia and a corresponding increase in circulating levels of insulin up to 100 muU/ml were observed in the recipient animals. Furthermore the IAEPs were shown to produce a near normal plasma glucose and insulin response to an intravenous glucose tolerance test. These findings suggest the feasibility of achieving amelioration of diabetes with allogeneic or xenogeneic pancreatic islets implanted as an artificial endocrine pancreas unit in the experimental animals which has the potential of future clinical application in man.