Islet Transplantation Using an Immunoprotective Membrane in Dogs That Have Undergone a Pancreatectomy

The use of a selectively permeable membrane to transplant nonsyngeneic tissue without accompanying immunosup-pressive therapy has been investigated using two approaches. The first hybrid artificial pancreas is implanted as a vascular shunt in which blood circulates through the lumen of a tubular membrane. The islet tissue is distributed within a chamber surrounding the membrane enclosed by an acrylic housing. Studies with diabetic dogs that have had pancreatectomies have demonstrated that these devices could replace exogenous insulin therapy for at least 6 months in five animals. This report presents data on two of these dogs, demonstrating viability and function of the transplanted tissue after 1 year. As an alternative to the vascular device, islets sealed within cylindrical permselective membrane chambers have been implanted in the peritoneum. Preliminary data from three dogs indicate that the nonvascular implants can also regulate fasting glucose levels in the diabetic dog model.