WASHINGTON, May 11 (Xinhua) -- Bone marrow stem cells from adults may help cure certain genetic eye diseases, researchers from the University of Cincinnati reported Friday.

The study with mice showed that bone marrow stem cells can switch roles and produce keratocan, a natural protein involved in the growth of the cornea -- the transparent, outer layer of the eyeball.

This ability of marrow cells to "differentiate" into keratocan-producing cells might provide a means for treating abnormal corneal cell growth in people.

In the laboratory, the researchers induced corneal abnormalities that mimicked genetic eye mutations and then injected bone marrow stem cells into the corneas to see if they altered the mutations.

The study showed that after only one week, the abnormal corneas of animal models injected with bone marrow stem cells began to change shape and heal.

Researchers found that bone marrow stem cells can contribute to the formation of connective tissues. They are now planning a clinical trial. If the trial succeeds, the procedure could help prevent blindness in future generations who suffer from genetic corneal diseases.

The research team also said that cornea transplants have been successful to some degree but do not always eliminate the problem. "When the donor cells disappear after a few years, the corneal disease often reoccurs," they noted.

However, "if we can place the stem cells inside the cornea, they will repair the lost function of the mutated gene, and stem cells can presumably renew themselves and maintain effective treatment longer, if not forever," they added.