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Cultured limbal stem cells can repair the corneal epithelium in eyes with limbal stem cell deficiency associated with corneal burns, a study showed.

Tissue restoration was successful in more than 75% of patients at up to 10 years, a team of Italian researchers reported.

"Our study shows that in patients with limbal stem cell deficiency who received cultured limbal stem cell grafts for corneal transplantation, the clinical results were successful at up to 10 years (at a median of 2 years) in more than 75% of the patients treated," the authors said. "Cultures of limbal stem cells thus represent a source of cells for transplantation in the treatment of burn-induced destruction of the human cornea."

The healthy limbus generates stem cells that renew and repair the corneal epithelium. Injury to the limbus may cause limbal stem cell deficiency. As a result, the corneal epithelium is formed by migrating bulbar conjunctival cells, leading to neovascularization, chronic inflammation, stromal scarring, corneal opacity and, potentially, loss of vision, the authors said.

The study included 113 eyes of 112 patients with a mean age of 46.5 years; 87.5% of patients had unilateral burns and 12.5% had bilateral burns. Two patients had bilateral severe limbal stem cell deficiency. Eighty-four percent of eyes had previously undergone unsuccessful corneal transplantation surgery.

Investigators obtained autologous limbal stem cells from uninjured fellow eyes and cultivated the cells on fibrin, a natural substrate. A total of 125 cultures were grafted in the 113 eyes.

Six patients did not complete the study. Mean follow-up was 2.91 years (maximum, 10 years).

Study data showed that at 1-year follow-up, with data available for 107 transplants, 73 grafts were deemed successful, 18 were partially successful and 16 eyes were failures. The final outcome was considered a clinical success in 76.6% of eyes and partial success in 13.1%; failure occurred in 10.3%.

All graft failures occurred in the first year, the authors reported.

Only those patients with an undamaged corneal stroma regained normal vision; 46 patients required penetrating keratoplasty, lamellar keratoplasty or phototherapeutic keratectomy to restore the damaged stroma; 21 of those patients regained complete vision and 25 regained partial vision.

July 1, 2010 (OSN SuperSite)