Corneas regrown from human stem cells

New York, July 3 (IANS) In the first known examples of constructing a tissue from an adult-derived human stem cell, researchers have identified a way to enhance regrowth of human corneal tissue to restore vision.

A molecule known as ABCB5 that acts as a marker for hard-to-find limbal stem cells was used for the identification process.

Limbal stem cells reside in the eye’s basal limbal epithelium, or limbus, and help maintain and regenerate corneal tissue. Their loss due to injury or disease is one of the leading causes of blindness.

Researchers were able to use antibodies detecting ABCB5 to zero in on the stem cells in tissue from deceased human donors and use them to regrow anatomically correct, fully functional human corneas in mice.

"Limbal stem cells are very rare, and successful transplants are dependent on these rare cells," said Bruce Ksander from Massachusetts Eye and Ear Infirmary in the US.

"This findings will now make it much easier to restore the corneal surface. It is a very good example of basic research moving quickly to a translational application," Ksander noted.

Using a mouse model, the researchers found that ABCB5 also occurs in limbal stem cells and is required for their maintenance and survival, and for corneal development and repair.

Mice lacking a functional ABCB5 gene lost their populations of limbal stem cells, and their corneas healed poorly after injury.

"ABCB5 allows limbal stem cells to survive, protecting them from apoptosis," Markus Frank from Boston Children’s Hospital in the US noted.

The work provides promise to burn victims, victims of chemical injury and others with damaging eye diseases.

The study appeared in the journal Nature.