Stephen Tsang, M.D., Ph.D.

Assistant Professor of Opthalmology
Attending Ophthalmologist, Edward Harkness Eye Institute
Columbia University, College of Physicians and Surgeons
dr.stemcells@gmail.com

Death of photoreceptor neurons in age-related macular degeneration (AMD) causes the loss of activities of daily living. AMD affects about 10 million Americans (approx 1 in 27 or 3.68% of the population), twice as many as other forms of neuronal degeneration, and its incidence is expected to double by 2020.

Stem cell transplantation has the potential to restore lost vision and provide treatment for advanced stages of retinal degeneration even in cases of significant photoreceptor loss. Our experimental approach involves the culture of human retinal stem cells from the ciliary body in eye-bank globes, and using those cultured cells to determine the combination of transcription factors involved in regulating their proliferation and differentiation into light-sensing neurons.

Our laboratory has also established a mouse embryonic stem cell line engineered with a photoreceptor-specific reporter Pde6g::GFP construct to express a protein that fluoresces a bright green when stem cell-derived photoreceptors are created. The retinas fluoresce in the outer nuclear layer indicating the formation of new photoreceptors derived from embryonic stem cells.

Select Publications

Gong J, Sagiv O, Cai H, Tsang SH, Del Priore LV. Effects of extracellular matrix and neighboring cells on induction of human embryonic stem cells into retinal or retinal pigment epithelial progenitors.  Exp Eye Res. 2008 Jun;86(6):957-65. Epub 2008 Mar 28.

Tsang S. H., Gouras P., Yamashita C. K., Fisher J., Farber D. B., and Goff S. P. (1996) Retinal Degeneration in Mice Lacking the  subunit of cGMP phosphodiesterase. Science 272: 1026-1029.