Mol Neurobiol (2012) 45:87–98 MSC for stroke. Osiris therapeutics has conducted multiple clinical trials using allogeneic MSC administered through systemic infusion. No stem-cell-related events have occurred and their studies provide extensive safety and provisional efficacy data for allogeneic bone-marrow- derived MSC administration to patients through FDA- approved clinical trials [4, 5, 33]. Patient safety and the potential benefit to risk ratio are always the foremost considerations by the Food and Drug Administration. This review has covered the potential benefits of MSC-based therapies for the treatment of neurodegenera- tive diseases, and Huntington’s disease in particular. We and many others have documented the biosafety of MSC therapies, which are now in phase III trials for some indications, and further safety and efficacy data are being collected by numerous groups. The need for safe and effective cellular therapies to treat HD is great. Current therapies only target symptoms, and there are no drugs or other treatments that effectively delay the relentless loss of striatal volume in affected patients. Extending MSC-based therapies to neuro- degenerative diseases, in particular those for which there are currently no effective treatments, such as HD (Fig. 2), could have a high potential benefit to risk ratio. Acknowledgments Our work on MSC therapy for Huntington’s disease and other neurodegenerative disorders is funded by the California Institute for Regenerative Medicine (CIRM) grants no. TR1-01257 (Nolta) and DR2-05415 (Wheelock), UC Davis CTSC pilot project 2P51RR000169-49, CIRM Training Grant to UC Davis, CIRM Bridges to Stem Cell Training Grant to California State University, Sacramento, NIH NHLBI 1RO1 HL073256-01 (Nolta), NIH Director’s transformative award 1R01GM099688 (Nolta), 5P30AG010129-19 (DeCarli PI: Olson-Pilot project PI), and philan- thropic donors from the HD community including the Roberson family and TeamKJ. We thank the HD patients and their families who provide daily inspiration to our group. Author contributions Scott D. Olson, Kari Pollock, Amal Kambal, Whitney Cary, Gaela-Marie Mitchell, Jeremy Tempkin, Hyun Sook Kim and Jeannine McGee performed conception and design, collection and/or assembly of data, data analysis and interpretation, final approval of manuscript. Gerhard Bauer performed manuscript writing and final approval of manuscript. 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