TABLE 1. Summary of Transplantation Approaches.

Transplantation Approaches:	Outcomes:	Representative References
Adrenal Medulla Transplants	Cell survival poor, failed in blinded clinical trials	[27-30]
Carotid Body Grafts	Minimal benefits in clinical trials	[31-37]
Allogenic Human FVM Transplants	Ethical concerns, failed in clinical trials despite several spectacular successes reported in open-label studies from several different centers, Lewy body like pathology in grafts, graft-induced dyskinesias in many patients	[38-49]
Porcine FVM Xenotransplants	Need chronic immunosuppression, failed in clinical trial despite success in preclinical studies	[50-59]
hRPEC transplants	Post-natal hRPEC failed in placebo controlled clinical trials, but embryonic hRPEC were successfully engrafted in animal studies and effective in open-labeled clinical trials. No need for immunosuppression even in the case of embryonic hRPEC xenografts. However, limited autopsy report from post-natal hRPEC grafted patent showed poor cell survival and macrophage infiltration of graft sites.	[60-71]
hES Transplant	No clinical trial yet, cell death of transplanted cells reported even with immunosuppression	[72-77]
iPSC Transplant	No clinical trial yet, immunosuppression necessary to avoid cell death in grafts	[17, 78-82]