Times of India
9 April 2009

Researchers at the University of Pittsburgh School of Medicine have found that stem cells collected from human corneas restore transparency and don’t trigger a rejection response when injected into eyes that are scarred and hazy, raising hopes that cell–based therapies to treat human corneal blindness and vision impairment may soon be available.

“Our experiments indicate that after stem cell treatment, mouse eyes that initially had corneal defects looked no different than mouse eyes that had never been damaged,” said senior investigator James L. Funderburgh, Ph.D., associate professor, Department of Ophthalmology.

Few years ago, Funderburgh and his colleagues identified stem cells in a layer of the cornea called the stroma, and they recently showed that even after many rounds of expansion in the lab, these cells continued to produce the biochemical components, or matrix, of the cornea.

One such protein is called lumican, which plays a critical role in giving the cornea the correct structure to make it transparent.

Funderburgh said that mice that lack the ability to produce lumican develop opaque areas of their corneas comparable to the scar tissue that human eyes form in response to trauma and inflammation.

However, three months after the lumican–deficient mouse eyes were injected with human adult corneal stem cells, transparency was restored.

The cornea and its stromal stem cells themselves appear to be “immune privileged,” meaning they don’t trigger a significant immune response even when transplanted across species, as in the Pitt experiments.

“Several kinds of experiments indicated that the human cells were alive and making lumican, and that the tissue had rebuilt properly,” Dr. Funderburgh noted.