Corneal Epithelial Stem Cells Repopulate the Donor Area Within 1 Year
Ophthalmology, December 2016
Busin et al. set out to determine whether limbal epithelial stem cells (LESCs) repopulate the site harvested for limbal autograft transplantation (LAT) and, if so, when. Based on the expression of LESC markers, they found that the cells were able to repopulate the donor area as early as 12 months after explanting.
LAT is a surgical procedure that has been used successfully for unilateral limbal epithelial stem cell (LESC) deficiency. Unlike ex vivo LESC expansion, this method is ideal for treating severe chemical burns that require a combined conjunctival-limbal transplant. However, despite the effectiveness of LAT, concerns have been raised about potential iatrogenic damage to the healthy donor eye, as LAT requires a larger amount of donor tissue than does ex vivo expansion.
In this interventional case series, the researchers studied 6 patients who had previously undergone LAT for unilateral acquired limbal stem cell deficiency after a chemical burn (average time after LAT, 3.5 ± 2.07 years; range, 1-7 years). Corneal limbal specimens were obtained from the donor eye of each patient at 2 sites: the area from which donor cells had been harvested and an untouched control area.
The researchers isolated the LESCs from these areas; and cellular, immunohistochemistry, and histologic parameters were assessed to compare differences between LESCs taken from harvested versus control sites. They found that specific cells markers (p63, Ki67, K12), percentage of LESCs, cell doubling, and number of passages in culture did not differ significantly between harvested and control sites as early as 12 months after surgery. However, the distinctive structure of the palisades of Vogt was found only in 2 of 6 specimens from the harvested sites (in patients who had undergone LAT 3 and 4 years earlier). LESCs from the 4 samples lacking palisades of Vogt had a thicker epithelium, longer epithelial cells, and stromal irregularities. The researchers hypothesized that the time required for full restoration of normal anatomic features is beyond the time frame of their study.
The researchers concluded that LAT is an effective procedure for cases of unilateral ocular surface damage that cannot be treated by simple grafting of LESCs cultured ex vivo. Further, they stated that their study demonstrates, for the first time, the safety of LAT for the donor eye.
The original article can be found here.