
Scientists have successfully reversed mice blindness by harvesting and using purified human stem cells to repair their damaged corneas. Five weeks later, the corneas of the mice were functioning normally, and were the same thickness as the corneas of healthy mice. Thirteen months later, their vision was still normal.
Published in Nature, the Boston-based scientific collaborative, led by Harvard Stem Cell Institute (HSCI) researchers are now pursuing FDA-approval for the technique before moving on to patient clinical trials.
Until now limbal stem cell transplants from an uninjured eye or deceased organ donor have had promising results, but outcomes have been inconsistent.
“Previously published work on limbal epithelial cell grafts showed that when more than three per cent of transplanted cells were stem cells, transplants were successful – less than three per cent and the transplants were not,” said HSCI Affiliated Faculty member Natasha Frank.
“The question in the field then was whether we could enrich the limbal stem cells. But until this study there was no specific marker that could isolate these cells.”
The biological marker the researchers found is the ABCB5 protein, which is located on the surface of limbal stem cells. The team then developed an antibody that could tag limbal stem cells in a general sample of human limbal cells, making it possible to purify only the cells responsible for successful limbal cell transplants.
“I think a very exciting part of the study is that even though there is a lot of evidence that adult stem cells contribute to tissue regeneration, what we see is basically the first evidence that you can take adult stem cells and regrow the organ that’s been damaged,” said Ms. Frank.
The research team hopes to find a way to replicate limbal stem cells so that a single donor eye can produce enough transplantable cells to help several patients.