Eye injuries that damage the cornea are usually irreversible and cause blindness. But a new clinical trial has repaired this damage in patients thanks to a transplant of stem cells from their healthy eyes.
The cornea is the outer layer of the eye, which focuses light towards the retina. Since it’s on the frontline of potential hazards from the outside world, the cornea features a population of limbal epithelial stem cells, which repair minor damage to keep the surface smooth and functional.
Unfortunately, injuries like thermal or chemical burns can damage the cornea beyond the capability of these resident stem cells. There’s not much else that can be done – even a cornea transplant won’t take hold if the damage is too severe.
The new study, conducted by scientists at Massachusetts Eye and Ear, investigated a new treatment called cultivated autologous limbal epithelial cells (CALEC). This involves removing stem cells from a patient’s uninjured eye, growing their population in the lab for a few weeks, then surgically transplanting them into the injured eye.
The phase 1/2 trial recruited 14 patients to undergo the procedure, and followed them for 18 months afterwards. Success was primarily judged by how effectively the treatment repaired the cornea’s surface, while a secondary test analyzed improvements to visual acuity.
By the first checkup at three months, the corneas of seven (50%) of the participants had been completely restored. By the 12-month mark, that number had increased to 11 (79%) patients. Two other participants met the definition for partial success, so the team claims an overall success rate of 92% for CALEC.
It’s worth noting that three participants did require a second transplant of stem cells, with one of them going on to reach the mark of complete success by the end of the study. In tests of visual acuity in the damaged eye, the majority of patients regained some sight, with some advancing from legally blind to low vision.
No serious adverse effects that were attributed to the procedure were seen in the patients, in either the donor or recipient eyes. The researchers say that this success paves the way for further trials with larger cohorts and longer follow-ups, before CALEC is submitted for FDA approval.
The research was published in the journal Nature Communications.
Source: Massachusetts General Brigham