Transplantation of microencapsulated pancreatic human islets for therapy of diabetes mellitus. A preliminary report.

To circumvent immune destruction of pancreatic islet grafts, human islets were deposited, enveloped within algin-polyaminoacidic microcapsules, in artificial prostheses directly anastomosed to blood vessels. Three dogs and two patients with insulin-dependent diabetes received transplantations with microencapsulated human islets embodied in arterial or AV prosthesis bypasses without any pharmacologic immunosuppression. Graft function was documented in all recipients by significative production and sustenance of serum C-peptide levels, although insulin independence was consistently achieved in only one of three dogs and, transiently, in one of two patients. On retrieval of grafted prostheses, viable human islets were found in microcapsules, most of which were freely dispersed in the vascular chambers. Vascular prostheses may represent a suitable site of implantation for large numbers of human islets, immunoprotected in semipermeable and biocompatible microcapsules, and be a novel strategy for therapy of insulin-dependent diabetes mellitus (IDDM).