A procedure that takes stem cells from a patient's healthy eye and transplants them into the patient's damaged eye safely restored corneal surfaces in 14 people who were followed for 18 months in a small clinical trial. The results of the study, led by researchers and surgeons at Harvard Medical School and Massachusetts Eye and Ear, were published March 4 in Nature Communications.
- By RYAN JASLOW | Massachusetts Eye and Ear
The stem cell treatment for blinding cornea injuries - called cultivated autologous limbal epithelial cell (CALEC) transplantation - was developed at Mass Eye and Ear. It consists of removing stem cells from an injured patient's healthy eye with a biopsy, expanding them into a cellular tissue graft in a novel manufacturing process that takes two to three weeks, and then surgically transplanting the graft into the patient's damaged eye.
The procedure remains experimental and is currently not offered at Mass Eye and Ear or any U.S. hospital, and additional studies will be needed before the treatment is submitted for federal approval.
"Our first trial showed that CALEC was safe and the treatment was possible," said principal investigator Ula Jurkunas, associate director of the Cornea Service and HMS professor of ophthalmology at Mass Eye and Ear. "Now we have this new data supporting that CALEC is more than 90 percent effective at restoring the cornea's surface, which makes a meaningful difference in individuals with cornea damage that was considered untreatable."
The cornea is the clear, outermost layer of the eye. Its outer border, the limbus, contains a large volume of healthy stem cells called limbal epithelial cells, which maintain the eye's smooth surface.
People who suffer a cornea injury, such as a chemical burn, infection, or other trauma, often experience persistent pain and visual difficulties. These injuries can also deplete the limbal epithelial cells, which can never regenerate. Without limbal stem cells, the surface of the eye can't heal, and the permanently damaged surface can't undergo a corneal transplant, the current standard of care for vision rehabilitation.
This need led Jurkunas and Reza Dana, the HMS Claes H. Dohlman Professor of Ophthalmology and director of the Cornea Service at Mass Eye and Ear, to explore a new approach for regenerating limbal epithelial cells. After nearly two decades of work, following preclinical studies and collaborations with researchers at Dana-Farber Cancer Institute and Boston Children's Hospital, the researchers managed to consistently manufacture CALEC grafts that met stringent quality criteria needed for human transplantation. The first patient was treated in 2018 at Mass Eye and Ear.
The researchers caution that this approach is suitable solely for patients with damage to only one eye.
"Our future hope is to set up an allogeneic manufacturing process starting with limbal stem cells from a normal cadaveric donor eye," said Jerome Ritz of Dana-Farber's Connell and O'Reilly Families Cell Manipulation Core Facility, where the stem cell grafts are manufactured. "This will hopefully expand the use of this approach and make it possible to treat patients who have damage to both eyes."
