Intermittent intraperitoneal implantation of islets in rat islet transplantation

Two critical issues need to be addressed regarding islet cell transplantation: obtaining sufficient supply of cells for implantation, and the maintenance of the viability of these cells. Our present study has two protocols. One is islet cell implantation under the renal capsule, and the other, repeated injection of islet cells into the peritoneal cavity. These two methods were compared in an isogeneic transplant model in the rat to determine the more clinically beneficial method. Transplantation of 2000-2500 islet under the capsule of the kidney resulted in normalized blood sugar levels for more than 100 days in four of five rats with hyperglycemia. However, normalization for the same duration by islet cell injection into the peritoneal cavity necessitated repetition of injections in two out of three tested rats. In view of the similarity of the results obtained with these two protocols, intraperitoneal implantation of a few cells is preferable, because the need for prolonged cell preservation is avoided.