A University of South Florida neuroscientist reports that the cutting-edge research study of human stem cells in primates with Parkinson's disease is compelling on several fronts , particularly how the transplanted cells did their job of easing disease symptoms.
Paul R. Sanberg, DSc, PhD, Distinguished Professor of Neurosurgery and Director of the Center for Aging and Brain Repair at USF Health, wrote the commentary "Neural Stem Cells for Parkinson's Disease: To Protect and Repair", published July 9 in the 'Early Edition' online version of journal Proceedings of the National Academy of Sciences of the United States of America (PNAS). The expert commentary is a companion piece to the study conducted by Gene Redmond and colleagues at Yale and Harvard Universities and the Burnham Institute.
That NIH-funded study showed that only a small number of stem cells turned into dopamine-producing cells , not enough to improve the primates, function by replacing missing neurons. Instead, some stem cells turned into astrocytes, a supportive brain cell that produces neuron-nourishing chemicals. The researchers also identified in the brains of the primate recipients a significant amount of dopamine-producing neurons that were not derived from stem cells. The results suggest that stem cells may actually trigger the brain's own self-repair mechanisms by pumping out molecules that boost nerve survival and blood vessel development and decrease neural degeneration.
"We at the Center for Aging and Brain Repair at USF Health have been arguing, for some time now, that stem cells are important for brain repair because they provide growth factors and because they send signals to the brain to help it repair itself," Dr. Sanberg said. "This study in primates showed the same effects -- that the stem cells are there to act as facilators of repair versus the original hypothesis that stem cells are transplanted to merely replace an injured cell."