A Boston-based scientific collaborative, led by HSCI researchers at Massachusetts Eye and Ear/Schepens Eye Research Institute has discovered a way to collect the best cell type for regenerating a damaged cornea—the clear membrane that covers the pupil and directs light into the back of the eye.
Corneal blindness is a clouding of vision that results when blood vessels grow into the cornea. It can be caused by an injury, infection, or autoimmune disease that destroys an actively regenerating population of stem cells located in an area behind the cornea, called the limbus. At present, limbal stem cell transplants from an uninjured eye or deceased organ donor have had promising, yet inconsistent, results.
The investigators found that transplant success is greatly improved by purifying the limbal stem cells. The team is now pursuing FDA-approval for the technique before moving on to clinical trials.
“Previously, work on limbal cell grafts showed that when more than three percent of transplanted cells were stem cells, transplants were successful—less than three percent and the transplants were not,” said co-senior investigator Natasha Frank, MD. “The question in the field then was whether we could enrich the limbal stem cells. But until this study there was no specific marker that could isolate these cells,” she added.
The biological marker the researchers found is the ABCB5 protein, which is located on the surface of limbal stem cells. The team then developed an antibody that could tag limbal stem cells, making it possible to purify only the cells responsible for successful limbal cell transplants.
A second team of scientists led by HSCI’s Ula Jurkanas, MD, also at Massachusetts Eye and Ear, is investigating how to use patient limbal stem cells for the treatment of limbal stem cell deficiency. They are collaborating with the Center for Human Cell Therapy at Boston Children’s Hospital to translate the work for the clinic.