ISOTRANSPLANTATION OF MICROENCAPSULATED PARATHYROID TISSUE IN RATS

Permanent hypoparathyroidism is one of the most difficult of all endoc rine disorders to treat medically. While autotransplantation of parath yroid tissue is clinically established, allotransplantation without im munosuppression is still at the level of animal experiments. Although persons affected by hypoparathyroidism are facing a clearly reduced qu ality of life, hypoparathyroidism rarely is a life threatening conditi on. Therefore, systemic immunosuppression for recipients of allotransp lants is not justified. A conceptional alternative would be protecting the tissue to be transplanted from the immunologic response by coatin g it with a semipermeable membrane (microencapsulation). In 1994, we s ucceeded in iso-, allo- and xenotransplantation of microencapsulated p arathyroid tissue in an animal model. Unfortunately, prior to the firs t clinical use, further analysis of the coating substance (alginate) d emonstrated that it has mitogenic properties. Here, we report on the f irst successful transplantation of microencapsulated parathyroid tissu e using a purified, non-mitogenic alginate which is suitable for clini cal use.