Light-sensing retinal eye cells have been grown from human skin cells for the first time. This raises the future possibility of restoring vision to patients with retinas damaged by certain degenerative diseases, by growing rescue or repair cells from the patient's skin. In the shorter term, the breakthrough will further research on genetically-linked eye disorders. For example, scientists will be able to cultivate retinal cells with a chosen genetic defect and then use them to screen potential new drugs that might treat or cure a given condition. The team, from the University of Wisconsin, US, published their research in the August issue of Proceedings of the National Academy of Sciences.
Many genetic conditions lead to degeneration of the retina resulting in partial or complete loss of vision. Two such conditions are retinitis pigmentosa and macular degeneration (affecting an estimated one million people worldwide), both of which lead to a narrowed visual field, and eventual loss of sight. 'In particular these diseases are quite devastating to the patients who are affected by them,' stated David Gamm, an assistant professor of ophthalmology and visual sciences at the University of Wisconsin and lead researcher on the study. 'They rob them of their vision either when they are younger, in the case of retinitis pigmentosa, or when they are older, in the case of macular degeneration. And there are no cures and very few if any treatments for them.' Gamm says his research could benefit people who have these conditions.
His team successfully grew multiple types of retinal cells from both induced pluripotent stem cells (iPS cells), derived from human skin cells as well as the more traditional embryonic stem cells - both of which have the capability of growing in to almost every kind of cell in the body. 'This is an important step forward for us, as it not only confirms that multiple retinal cells can be derived from human iPS cells using the Wisconsin approach, but also shows how similar the process is to normal human retinal development,' said Gamm. 'That is quite remarkable given that the starting cell is so different from a retinal cell and the whole process takes place in a plastic dish.' These cultivated retinal cells could be used to screen new drugs, or even replace damaged retinal cells, in theory.
Gamm believes the same technique can be used to help scientists find treatments for other genetic diseases that affect different parts of the body. 'Now we could take theoretically any human disease, especially those that have specific gene defects underlying them, and produce cell types of interest in those diseases and test them directly for the efficacy of various drugs or how in fact those cells die in disease,' he said.