Contributions of Europeans to Xenotransplantation Research: 2. Pig Islet and Cell Xenotransplantation.

Pig islet xenotransplantation in nonhuman primates (NHPs) has made considerable progress during the past 30 years, and European scientists in both Europe and the USA have contributed to this progress. At times, there have been, or are, active research programs in Sweden, Germany, Belgium, and the USA. The first clinical experiments of wild-type (i.e., genetically-unmodified) pig islet xenotransplantation were carried out by Groth and his colleagues in Stockholm in 1994, but without significant success. Hering's group in Minneapolis was the first to report prolonged survival of wild-type pig islets in NHPs in 2006, and the first report of insulin-independence for >12 months was by a "European" research team at the University of Pittsburgh in 2009. Recent progress has been slow, in part through a lack of funding, but recent advances in pig organ xenotransplantation suggest that pig islet xenotransplantation is poised for clinical experiments in the near future. In addition, there have been encouraging experimental studies of pig neural cell injections into the brains of monkeys with a pharmacologically-induced Parkinson's disease.