The preclinical results are highly relevant to human disorders of vision loss, the most notable of which is dry age-related macular degeneration (AMD). The study is available online at http://onlinelibrary.wiley.com/doi/10.1111/j.1460-9568.2011.07970.x/abstract and will be featured as the cover article in the February issue of the international peer-reviewed European Journal of Neuroscience.
This research was conducted in collaboration with a team of researchers led by Raymond Lund, Ph.D., Professor Emeritus of Ophthalmology, and Trevor McGill, Ph.D., Research Assistant Professor at the Casey Eye Institute, Oregon Health and Science University.
The results of the study show that photoreceptors, the key cells of the eye involved in vision, were protected from degeneration following transplantation of HuCNS-SC cells into the Royal College of Surgeons (RCS) rat. The RCS rat is a well-established model of retinal disease which has been used extensively to evaluate potential cell therapies. Moreover, the number of cone photoreceptors, which are responsible for central vision, remained constant over an extended period, consistent with the sustained visual acuity and light sensitivity observed in the study. In humans, degeneration of the cone photoreceptors account for the unique pattern of visual loss in dry AMD.
"These results are the most robust shown to date in this animal model," said Dr. Lund, one of the study's lead investigators. "One of the more striking findings is that the effect on vision was long-lasting and correlated with the survival of HuCNS-SC cells more than seven months after transplantation, which is substantially longer than other cell types transplanted into this same model. Also important, particularly for potential clinical application, was that the cells spread from the site of initial application to cover more of the retina over time. These data suggest that HuCNS-SC cells appear to be a well-suited candidate for cell therapy in retinal degenerative conditions."
Alexandra Capela, Ph.D., another of the study's investigators and a senior scientist at StemCells, commented, "This study showed that the HuCNS-SC cells persisted and migrated throughout the retina, with no evidence of abnormal cell formation, which supports our hypothesis of a single transplant therapeutic. With this research, then, we have shown that vision can be positively impacted with a simple approach that does not require replacing photoreceptors or the RPE cells. We look forward to investigating this promising approach in the clinic later this year."