Transplanting Fetal Neural Xenogeneic Cells in Parkinson’s and Huntington’s Disease Models

Fetal allogeneic neural transplants have been repeatedly shown to cause functional recovery in animal models of neurodegenerative diseases (1–8), improve symptoms, and reduce drug-induced side effects in patients with Parkinson’s disease (9–13). It has, however, proven difficult to obtain human fetal tissue for neural transplantation, both from a practical and ethical standpoint (14–16). Thus, although a therapeutic rationale exists for using allogeneic neural transplantation in Parkinson’s (and Huntington’s) disease, the limited availability of human fetal neural tissue poses serious limitations on clinical application (17). Neural xenotransplantation, which is transplantation of fetal neuroblasts obtained from homologous neural structures of a different (mammalian) species into the adult brain, overcomes many of the limitations associated with the use of human fetuses. For clinical use, neuroblasts at precisely defined embryonic ages can be prepared in large quantities and in a sterile fashion from the fetuses of especially bred pathogen-free xenogeneic donors.