Think twice the next time you wipe a few flecks of dandruff from your shoulder. You might be shedding cells that may someday restore human vision.
Thomas Reh and colleagues at the University of Washington, in Seattle, have generated light-sensing retinal cells, called photoreceptors, from adult human skin cells. They then transplanted the cells into a mouse retina, showing that the photoreceptors integrated normally into the surrounding tissue. This technological feat raises hopes for the development of treatments for retinal diseases, such as retinitis pigmentosa and macular degeneration, which cause visual impairment or blindness in millions of people in the U.S.
Researchers used induced pluripotent stem (iPS) cell technology, activating a handful of genes in skin cells in order to revert them to a flexible embryonic state. They then used previously developed methods to differentiate the cells into photoreceptors. While Reh’s team has done similar experiments using embryonic stem cells, iPS cells are a preferable source for cell replacement therapies because they can be derived from the patient. Skin cells are a ready source of cells that are tissue-matched to the recipient, bypassing problems associated with immune rejection of stem-cell transplants.