Pig islet xenotransplantation

Allogeneic islet transplantation faces serious difficulties since organ shortage is recurrent and the lack of donors is aggravated by the fact that several pancreas donors are often needed to treat one diabetic recipient. Another source of insulin-producing cells would therefore be of major interest and pigs represent a possible and serious way of obtaining such cells. Pig islet grafts may appear difficult due to the species barrier, but recent reports demonstrate that pig islets may function in primates for at least six months. However, pig islet xenotransplantation, in the context of clinical application, still has to overcome several hurdles such as selection of pig islet donors (germfree conditions), maturity, isolation and function of islets, possible xenozoonosis, as weil as a strong immunosuppression of the recipient. The choice between clinically applicable immune regimens and/or encapsulation is also discussed. Recently acquired knowledge of islet transplantation is summarized in this chapter.