Losing your vision? There's a cell for that!

I feel like I wake up every morning and experience the same few things: a hot cup of coffee, a cold bowl of cereal and an article describing some breakthrough in stem cell technology. Yesterday was certainly no different, as a paper published in the journal Lancet described an exciting study by researchers from several institutions regarding the treatment of disorders of the eye.

Figure 1: Dr. Steven Schwartz, the lead author on the above study

The scientists injected cells derived from human embryonic stem cells (hESCs) under the retina of patients in the study. These patients suffered from two diseases that lead to vision loss: age related macular degeneration and Stargardt macular dystrophy. They found that more than half of the patients improved their eyesight, which is pretty remarkable considering that it was extremely unlikely that their vision would have improved on its own. More importantly, however, was that none of the patients showed adverse reactions to the cells!

A common question I get about these therapies is as follows: if we have supplies of stem cells and if they work fairly well in animals, why aren't we using them to cure humans? The biggest roadblock for the use of stem cells in the clinic is a lack of data regarding safety. Consider this: stem cells are naturally programmed to grow into all of the cells that your body needs. As you can imagine, many scientists are concerned that reimplanting these cells into our bodies may lead to cancer, which can be loosely defined as the out of control growth of a population of cells. A robust rejection of the cells by your immune system is also a big concern!

Without a doubt, this study is an important landmark in the field of stem cell biology. Now that we've proved (at least, early on) that these cells are safe, you'll probably see many more innovative use of stem cells in human trials very soon!