Simple limbal epithelial transplantation (SLET): Review of indications, surgical technique, mechanism, outcomes, limitations, and impact

Abstract

Simple limbal epithelial transplantation (SLET) is an innovative limbal stem cell transplantation technique that has gained increasing popularity over the last few years. Different groups from across the world have published the clinical results of SLET in large case series with varying types and severities of limbal stem cell deficiency (LSCD). This review attempts to place all the available knowledge on SLET together in one place for the benefit of not only cornea specialists and trainees but also for residents and general ophthalmologists. It follows a balanced approach of blending evidence with experience by providing an objective analysis of published results along with helpful insights from subject experts, starting from preoperative considerations including the role of newer imaging modalities to the technical aspects of the surgery itself and the management of possible complications. Original data and novel insights on allogeneic SLET for bilateral LSCD are included in the review to address the few remaining lacunae in the existing literature on this topic. This review intends to inform, educate, and empower all aspiring and practicing SLET surgeons to optimize their clinical outcomes and to have maximal positive impact on the lives of the individuals affected by unilateral or bilateral chronic LSCD.

<p>Amniotic Membrane Transplantation in Ophthalmology: An Updated Perspective</p>

“…The donor tissue was cut into small pieces and these explants placed epithelial side up on top of the amniotic membrane in a circular manner around the cornea. This technique has been further explored by a number of studies, such as Shanbhag et al 78 and Borroni et al 79 Both these studies show SLET surgery to be an effective and safe surgical technique. One retrospective multicentre study using 68 eyes showed the success of SLET in 57 cases (83.8%) with a survival probability of greater than 80% at one-year post operatively.…”

Limbal Epithelial and Mesenchymal Stem Cell Therapy for Corneal Regeneration

“…Serial photographic imaging of eyes using fluorescein staining has clearly shown the multidirectional growth of epithelial cells from each transplant within the first few days which gradually coalesced to form a confluent stratified sheet of epithelium on the corneal surface by 10-14 days. 57 Amescua et al used high-resolution AS-OCT to show that this epithelial proliferation occurs on the hAM scaffold and the hAM itself becomes the new basement membrane for the regenerated epithelium (Figure 4(a-d)). 58 Histopathological and immunohistochemical analysis of excised corneal buttons from eyes undergoing PK after SLET also confirmed that the corneal surface epithelium was of corneal phenotype (CK3 + , CK12 + , CK19 − , MUC5AC − ) and also that there was focal retention of stem cells (ABCG2 + and Δp63α + ) in the basal epithelial layer of the newly regenerated epithelium.…”

“…A recent review summarized the outcomes of allogeneic SLET for bilateral LSCD in Stevens-Johnson syndrome, mucous membrane pemphigoid, ocular burns and severe chronic allergy in 30 eyes of 29 patients. 57 The patients underwent either living-related or cadaveric allogeneic SLET with an identical postoperative immunosuppression regimen. The median follow-up was 28 months (range: 13-66 months) with no significant difference at baseline between the living-related and cadaveric groups.…”

“…Kaplan Meier survival analysis showed statistically similar 5-year cumulative survival probability of 90% in the living related and 82% in the cadaveric donor group. 57 Summary, limitations, and future of LSCT for LSCD The main limitation of LSCT for unilateral and bilateral LSCD is that irrespective of the surgical technique, source of donor tissue, or post-operative care, about 20-30% of all cases develop a recurrence of LSCD over the long term. The risk factors of failure have been studied in detail and are usually related to the severity of the pathology.…”

Surgery Versus ATMPs: An Example From Ophthalmology

“…• Simple limbal epithelial transplantation (SLET), reduces the tissue withdrawal of CLAu, but it can treat milder severity (superficial lesions) than CLET. In the SLET procedure, re-epithelialization is slower than in some of the other therapies (it takes about 5-6 weeks) (Sangwan et al, 2012;Swapna et al, 2019). • Cultured limbal epithelial transplantation (CLET) procedure (Pellegrini et al, 1997) has some advantages compared to CLAu, for example it starts from a smaller amount of limbal tissue (1-2 mm 2 ), minimizing the risk of injury to the healthy eye.…”