Simple limbal epithelial transplantation: Current status and future perspectives

Abstract

Abstract Damage to limbal stem cells as a result of injury or disease can lead to limbal stem cell deficiency (LSCD). This disease is characterized by decreased vision that is often painful and may progress to blindness. Clinical features include inflammation, neovascularization, and persistent cornea epithelial defects. Successful strategies for treatment involve transplantation of grafts harvested from the limbus of the alternate healthy eye, called conjunctival-limbal autograft (CLAU) and transplantation of limbal cell sheets cultured from limbal biopsies, termed cultured limbal epithelial transplantation (CLET). In 2012, Sangwan and colleagues presented simple limbal epithelial transplantation (SLET), a novel transplantation technique that combines the benefits of CLAU and CLET and avoids the challenges associated with both. In SLET a small biopsy from the limbus of the healthy eye is divided and distributed over human amniotic membrane, which is placed on the affected cornea. Outgrowth occurs from each small explant and a complete corneal epithelium is typically formed within 2 weeks. Advantages of SLET include reduced risk of iatrogenic LSCD occurring in the healthy cornea at harvest; direct transfer circumventing the need for cell culture; and the opportunity to perform biopsy harvest and transplantation in one operation. Success so far using SLET is comparable with CLAU and CLET. Of note, 336 of 404 (83%) operations using SLET resulted in restoration of the corneal epithelium, whereas visual acuity improved in 258 of the 373 (69%) reported cases. This review summarizes the results of 31 studies published on SLET since 2012. Progress, advantages, challenges, and suggestions for future studies are presented. Significance statement The present review examines work reporting simple limbal epithelial transplantation (SLET), an innovative technique that uses minimal limbal tissue from the healthy eye to regenerate the cornea in the limbal deficient diseased eye. Results since the introduction of SLET in 2012 suggest that the success rate is comparable to established techniques, conjunctival-limbal autograft and cultured limbal epithelial transplantation. However, SLET has the advantages of requiring a smaller biopsy, achieving harvest and transplantation in a single operation, and the unnecessity of cell culture laboratories. AlloSLET, a novel modification of SLET using allogeneic tissue, promises to further improve outcome through promotion of early resolution of inflammation in the injured/diseased eye.