Protection of Encapsulated Human Islets Implanted Without Immunosuppression in Patients With Type I or Type II Diabetes and in Nondiabetic Control Subjects

D. W. Scharp, C. J. Swanson, B. J. Olack, P. P. Latta, O. D. Hegre, E. J. Doherty, F. T. Gentile, K. S. Flavin, M. F. Ansara, P. E. Lacy
1994 Diabetes  
Human islets were macroencapsulated in permselective hollow fiber membrane devices and successfully allotransplanted subcutaneously with >90% viability after 2 weeks in situ. Recipients were patients with type I or type II diabetes and normal control subjects; none was immunosuppressed. Between 150 and 200 islet equivalents were implanted in each of the nine patients. No adverse patient complications were observed. Biocompatibility of devices was excellent. Insulin-positive P-cells were
more » ... -cells were confirmed in encapsulated islets recovered from the implanted devices in all patient populations including the type I diabetic patients. Glucose-stimulated insulin release could be demonstrated in vitro from recovered islets. These data demonstrate that macroencapsulated human islets can survive at the subcutaneous site and that permselective membranes can be designed to protect against both allogeneic immune responses as well as the autoimmune component of type I diabetes. A direct relationship between the level of glycemic control and the development of diabetic complications in type I diabetic patients was shown in the recent Diabetes Control and Complications Trial (1). Diabetic complications were significantly reduced in the group receiving intensive insulin therapy; however, diabetic complications did occur. The HbA lc levels were not normal, and a higher incidence of hypoglycemic episodes occurred in these patients. These findings clearly indicate the need for a therapy that will maintain normoglycemia at all times and, hopefully, prevent the complications of diabetes. Normoglycemia has been achieved with whole pancreas transplants without insulin therapy, but continuous administration of immunosuppressive drugs is required to maintain the transplants (2). Insulin independence and normoglycemia have also been achieved with islet transplants; however, From the Departments of Surgery (immunosuppressive drugs are also required to maintain the islet grafts (3,4). Recent studies in our laboratory have shown that encapsulation of rat islets in poly(acrylonitrileco-vinyl chloride) (acrylic-copolymer) hollow fibers will prevent rejection of the grafts without immunosuppression and that normoglycemia is maintained in diabetic mice after implantation of the islets either intraperitoneally or subcutaneously (5). The purpose of the present study was to determine whether similar types of hollow fibers would protect human islets from rejection and autoimmune destruction in diabetic patients. A small number of human islets were encapsulated in acrylic-copolymer hollow fibers, implanted subcutaneously in type I and type II diabetic patients and nondiabetic control subjects, and removed at the end of 2 weeks, and the viability and insulin secretory responses of the encapsulated islets were determined. RESEARCH DESIGN AND METHODS This study was approved by the Washington University Institution Review Board and reviewed as an Investigator IND by the Food and Drug Administration (BB-IND 5103). Three patients were selected for each group. The type I patients had diabetes for >20 years; the type II patients had diabetes for > 5 years and were receiving oral hypoglycemic agents for treatment of their diabetic state. Minimal microvascular and macrovascular complications were present in both groups. The nondiabetic control subjects were recruited from family members. In all patients, tests for human immunodeficiency virus (HIV), cytomegalovirus (CMV), and hepatitis were negative. Fasting and 2-h postprandial levels of blood glucose were determined before implantation of fibers and at 1 and 2 weeks after the fibers were implanted. Human islets. The islets used in this study came from a single pancreas obtained from a life-supported cadaver that was nondiabetic and was HIV, CMV, and hepatitis negative. Even though minimal risk of sensitization of the patients with islet antigens was present, a donor was selected who had an obscure HLA type (A 324 B 7ll8 DRW 15 _) and who was type O negative. The islets were isolated by the automated digestion filtration technique developed in our laboratory (6), cultured for 7 days at 24°C in tissue culture medium CMRL-1066 (Gibco, Grand Island, NY) and additives (10% fetal bovine serum, 2 mM L-glutamine, 100 U/ml penicillin, 100 (xg/ml streptomycin sulfate), and cryopreserved (7). An aliquot of the cryopreserved islets was used to determine viability and insulin secretory response by perifusion in vitro (8). Assays of the cryopreserved islets for bacteriological, fungal, and mycoplasmal contamination were negative. Hollow fibers. The acrylic-copolymer hollow fibers were obtained from CytoTherapeutics, Inc. (Providence, RI) and were sterilized by ethylene oxide exposure. The fibers were 1.5 cm long with an internal diameter of 800 jjim and a wall thickness of -100 jxm. A permselective membrane was present on both the outer and inner surfaces of the wall with a nominal molecular weight cut off of 65,000. Aliquots of the cryopreserved human islet preparation were thawed (7) , cultured overnight at 37°C, pelleted by centrifugation, and suspended in 1% alginate (Pronova, DIABETES, VOL. 43, SEPTEMBER 1994 1167
doi:10.2337/diab.43.9.1167 pmid:8070618 fatcat:24iperkdjngyfgku4nmzuargv4