[tt] Stem cell therapy makes cloudy corneas clear, according to Pitt researchers | Science Blog

[Brian Atkins]

http://www.scienceblog.com/cms/stem-cell-therapy-makes-cloudy-corneas-clear-according-pitt-researchers-20158.html

PITTSBURGH, April 9 - Stem cells collected from human corneas restore 
transparency and don't trigger a rejection response when injected into eyes that 
are scarred and hazy, according to experiments conducted in mice by researchers 
at the University of Pittsburgh School of Medicine. Their study will be 
published in the journal Stem Cells and appears online today.

The findings suggest that cell-based therapies might be an effective way to 
treat human corneal blindness and vision impairment due to the scarring that 
occurs after infection, trauma and other common eye problems, said senior 
investigator James L. Funderburgh, Ph.D., associate professor, Department of 
Ophthalmology. The Pitt corneal stem cells were able to remodel scar-like tissue 
back to normal.

"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," Dr. Funderburgh said.

The ability to grow millions of the cells in the lab could make it possible to 
create an off-the-shelf product, which would be especially useful in countries 
that have limited medical and surgical resources but a great burden of eye 
disease due to infections and trauma.

"Corneal scars are permanent, so the best available solution is corneal 
transplant," Dr. Funderburgh said. "Transplants have a high success rate, but 
they don't last forever. The current popularity of LASIK corrective eye surgery 
is expected to substantially reduce the availability of donor tissue because the 
procedure alters the cornea in a way that makes it unsuitable for transplantation."

A few years ago, Dr. Funderburgh and other University of Pittsburgh researchers 
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.

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, Dr. Funderburgh said. But 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.

In the next steps, the researchers intend to use the stem cells to treat lab 
animals that have corneal scars to see if they, too, can be repaired with stem 
cells. Under the auspices of UPMC Eye Center's recently established Center for 
Vision Restoration, they plan also to develop the necessary protocols to enable 
clinical testing of the cells.

-- 
Brian Atkins
Singularity Institute for Artificial Intelligence
http://www.singinst.org/