Islet encapsulation

Abstract

Type 1 diabetes is an autoimmune disorder that destroys the insulin-producing cells of the pancreas. The mainstay of treatment is replacement of insulin through injectable exogenous insulin. Improvements in islet isolation techniques and immunosuppression regimens have made islet transplants a treatment option for select patients. Islet transplants have improved graft function over the years; however, graft function beyond year two is rare and notably these patients require immunosuppression to prevent rejection. Cell encapsulation has been proposed for numerous cell types, but it has found increasing enthusiasm for islets. Since islet transplants have experienced a myriad of success, the next step is to improve graft function and avoid systemically toxic immunosuppressive regimens. Cell encapsulation hopes to accomplish this goal. Encapsulation involves placing cells in a semipermeable biocompatible hydrogel that allows the passage of nutrients and oxygen and however blocks immune regulators from destroying the cell, thus avoiding systemic drugs. Several advances in encapsulation engineering and cell viability promise to make this a revolutionary discovery. This paper provides a comprehensive review of cell encapsulation of islets for the treatment of type 1 diabetes including a historical outlook, current research, and future studies.