Procedure may someday replace transplants in people, experts say
FRIDAY, April 10 (HealthDay News) -- Stem cells injected into the eyes of mice with defective corneas returned the corneas to a more normal appearance, a new study has found.
Researchers hope the procedure might one day be an alternative to corneal transplants in humans. About 40,000 such transplants are done each year in the United States.
"The stem cells took the scar-like matrix, remodeled it and made it more like normal," said senior investigator James Funderburgh, an associate professor of ophthalmology at the University of Pittsburgh. "We were surprised and delighted."
A report on the study is in the April 9 online edition of the journal Stem Cells.
The cornea is the transparent, front layer of the eye that serves as a protective barrier and, along with the lens, helps focus light. Corneas can develop scar tissue from chronic inflammation caused by infections or other conditions and by injuries, such as chemical or thermal burns or other trauma.
Scar tissue can cause the cornea to lose its transparency, preventing it from focusing light, and this can lead to a loss of visual acuity, including cloudy, hazy vision sometimes described as looking through frosted glass.
"The only effective therapy is corneal transplant," Funderburgh said.
Several years ago, using human cadavers, Funderburgh and his colleagues collected stem cells from the stroma, a matrix of collagen fibers that gives the cornea its strength.
In a healthy cornea, the collagen fibers run parallel to each other and are highly organized. In a damaged cornea, the matrix is irregular and disorganized, he said.
After growing stem cell cultures in the lab, the researchers injected the stem cells into the eyes of mice bred to have defective corneas that mimic scar tissue in humans.
After three months, the stem c
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