Comparative analysis of long-term results of three epithelial cell transplantation procedures for treating limbal stem cell deficiency

This study compared the long-term outcome of different epithelial transplantation techniques to treat limbal stem cell deficiency (LSCD). We conducted a retrospective 15-year comparative systematic cohort study of patients with LSCD who underwent either cultivated limbal epithelial transplantation (CLET), simple limbal epithelial transplantation (SLET), or cultivated oral mucosal epithelial transplantation (COMET). We reviewed the demographic data, etiology, LSCD severity, best-corrected visual acuity, surgical outcomes, and complications. A total of 103 eyes of 94 patients (mean age, 45.0 ± 16.4 years) with LSCD were enrolled. The most common cause of LSCD was chemical injury (42.7 %). The median follow-up time was 75 months. The success rates of CLET, SLET, and COMET were 45.5 %, 77.8 %, and 57.8 %, respectively. The 7-year survival rates after CLET, SLET, and COMET were 50.0 %, 72.2 %, and 53.2 %, respectively. Steven-Johnson syndrome (SJS) had a significantly lower survival rate than other causes (p < 0.001), but SLET had a significantly higher survival rate than CLET (p = 0.018) and COMET (p = 0.047). Visual improvement of more than four Snellen lines was achieved in 53.1 % of successful cases and 28.2 % of failed cases. SJS, Schirmer I test <5 mm, and the presence of postoperative recurrent epithelial defects were significant risk factors for a failed surgery. All epithelial transplantation techniques had favorable long-term surgical outcomes. More than half of the patients achieved a stable ocular surface and visual acuity improvement up to 7 years postoperatively. SLET tends to have a better surgical outcome than CLET and COMET, especially in patients with SJS.

Focus on limbal stem cell deficiency and limbal cell transplantation

Limbal stem cell deficiency (LSCD) causes severe vision impairment and can lead to blindness, representing one of the most challenging ocular surface disorders. Stem cell deficiency can be congenital or, more often, acquired. The categorization of ocular surface transplantation techniques is crucial to achieving treatment homogeneity and quality of care, according to the anatomic source of the tissue being transplanted, genetic source, autologous or allogenic transplantation (to reflect histocompatibility in the latter group), and cell culture and tissue engineering techniques. The aim of this minireview is to provide a summary of the management of LSCD, from clinical characteristics and therapeutic outcomes to the development of novel therapeutic approaches. The manuscript also briefly summarizes recent findings in the current literature and outlines the future challenges to overcome in the management of the major types of ocular surface failure.

Longitudinal Changes in Corneal Epithelial Thickness and Reflectivity following Simple Limbal Epithelial Transplantation: An Optical Coherence Tomography-Based Study

PURPOSE

To describe the changes in corneal epithelial thickness and reflectivity following simple limbal epithelial transplantation (SLET) using anterior segment optical coherence tomography (ASOCT).

METHODS

This was a prospective imaging study of 31 eyes of 29 patients who had undergone autologous or allogeneic SLET for limbal stem cell deficiency and had stable, avascular surfaces postoperatively. ASOCT scans of all four quadrants were taken preoperatively and at 1-week, 1-month, 3-month, 6-month, and 1-year postoperative time points in the eyes undergoing SLET. Baseline scans were also taken from the normal eye in unilateral cases. The following parameters were obtained from the scans: (i) epithelial thickness (ET), (ii) stromal thickness, (iii) total corneal thickness, (iv) epithelial reflectivity (ER), (v) stromal reflectivity, and (vi) epithelial/stromal (ES) reflectivity ratio.

RESULTS

Chemical injury (24 eyes, 77.4%) was the most common indication for surgery. There was a significant improvement in the ET (184.8 ± 117.1 vs 60.3 ± 10 µm, p < .0001) and ER (144.5 ± 26.4 vs 120.9 ± 28.9, p < .0001) within the initial postoperative period following SLET, which remained stable at the end of 1 year follow-up. There was no difference in the ET of the post-SLET and normal eyes after the 3-month timepoint and this normalization was maintained until the end of the first year. A significant normalization was also noted in the ES reflectivity ratio at the end of 1 year (2.1 ± 0.8 vs 1 ± 0.2, p < .001). A significant correlation was found between the final visual acuity and the total corneal thickness (r = 0.942, p = .005).

CONCLUSION

There is a significant improvement in the epithelial thickness and reflectivity of the cornea in eyes undergoing SLET. ASOCT provides a reliable objective measure of these changes and can be used to monitor the outcomes in these eyes postoperatively.

Preliminary experience & rationale of primary allo Simple Limbal Epithelial Transplantation (SLET) following surgical excision of Ocular Surface Tumors

AIM

To report the preliminary outcomes and elucidate the possible rationale of alloSLET for primary ocular surface reconstruction following excision of extensive ocular surface tumors.

METHODS

Retrospective interventional case series with a minimum postoperative follow up of 1 year. AlloSLET was performed along with wide surgical excision and cryotherapy in 3 eyes.

RESULTS

Of the 2 eyes with extensive OSSN and one with an extensive pigmented lesion, there was no occurrence of symblepharon in all 3 eyes. No features suggestive of LSCD was noted in 2 eyes. In the child with xeroderma pigmentosum and OSSN, early peripheral vascularization was noted at 1 year of follow up with reduced vision secondary to amblyopia.

CONCLUSION

Primary alloSLET could be an alternative to primary autoSLET in eyes with extensive ocular surface tumors, commonly seen with ocular surface squamous neoplasia (OSSN) and pigmented lesions. This facilitates ocular surface reconstruction with reduced occurrence of symblepharon formation as well as limbal stem cell deficie4ncy (LSCD). It possibly, is the only option in eyes with OSSN with coexistent bilateral limbal insufficiency. It may obviate the need for autoSLET, primary or secondary in eyes with adequate residual limbus.

Visual rehabilitation with limbal autologous stem cells transplant and cataract surgery in a patient with ocular surface squamous neoplasia

Purpose

To describe the outcome of simple limbal epithelial transplantation along with Phacoemulsification and IOL implantation for visual rehabilitation in limbal stem cell deficiency due to ocular surface squamous neoplasia.

Observations

This case report of a 66-year-old woman clinically diagnosed with OSSN in her right eye involving all cornea and limbus meridians. Topical chemotherapy for tumor treatment was done, followed by SLET and sequential cataract surgery. The entire tumor could be clinically reduced with topical chemotherapy but a LSCD could not be avoided. After SLET, corneal transparency was restored, and anterior segment details could be seen, phacoemulsification was performed uneventfully. After a follow-up period of 18 months, stable ocular surface and visual acuity and no tumor recurrence was observed.

Conclusions

SLET is an option to restore not only corneal epithelium homeostasis but also gain cornea transparency, avoid keratoplasties and allow anterior segment surgeries to be performed.

Importance

This case report provide evidence of benefits of simple limbal epithelial transplantation in ocular surface squamous neoplasia and shows that cataract surgery could be performed uneventfully after limbal stem cell transplantation.

Clinical outcomes of modified simple limbal epithelial transplantation for limbal stem cell deficiency in Chinese population: a retrospective case series

Objective

To report the clinical outcomes of a novel surgical technique, namely simple limbal epithelial transplantation (SLET), for the treatment of limbal stem cell deficiency (LSCD).

Methods

Thirteen patients (13 eyes) with LSCD who underwent autologous (10 eyes) or allogeneic (3 eyes) modified SLET between 2018 and 2021 were enrolled in this study. Grades of symblepharon, corneal conjunctivalization, vascularization, opacification, and visual acuity (VA) were evaluated preoperatively and postoperatively. In 2 cases, in vivo confocal microscopy (IVCM) and impression cytology (IC) were performed to assess the proliferation and degeneration of limbal tissue.

Results

At a postoperative follow-up of 6.5±5.3 (range, 2–20) months, 10 (10/13, 76.92%) eyes maintained a successful outcome. The grades of symblepharon, corneal conjunctivalization, vascularization, and opacification were significantly improved after SLET (P<0.05). Two-line improvement in VA was found in 6 (6/10, 60%) eyes of the successful cases. Recurrence of LSCD occurred in 3 (3/13, 23.08%) eyes, and conjunctival cyst occurred in 1 patient. After SLET, the morphology and structure of corneal epithelial cells and epithelial transition around the limbal tissue fragments were detected by IVCM and IC.

Conclusions

Our findings suggest that the SLET is a safe and effective technique for the treatment of LSCD. The corneal stroma and hAM can provide protection and nutrition for the limbal stem cells (LSCs) without negatively influencing the clinical outcomes. IVCM and IC after SLET can evaluate the effectiveness of surgery and the transition of LSCs and corneal epithelial cells.

Autologous transplantation of conjunctiva by modifying simple limbal epithelial transplantation for limbal stem cell deficiency

PURPOSE

As a treatment to replace regenerative medicine to treat limbal stem cell deficiency (LSCD), we performed 4 consecutive cases of autologous transplantation of conjunctival explants by modifying simple limbal epithelial transplantation (SLET).

STUDY DESIGN

Single-center case series.

METHODS

Four patients with LSCD were enrolled in this study. After resection of scar tissue with neovascularization from the ocular surface, human amniotic membrane (AM) was placed over the bare ocular surface. The bulbar conjunctiva of the operated eye was dissected at the temporal superior fornix, divided into small pieces, and transplanted onto AM with fibrin glue. Keratoplasty was performed simultaneously or few months after surgery.

RESULTS

Epithelialization was achieved in all patients. Best-corrected visual acuity was improved in all patients.

CONCLUSION

This is the first report of ocular surface reconstruction using autologous conjunctival epithelial transplants from the affected eye. Transplantation by modifying SLET effectively restored a clear corneal surface with minimal neovascularization in 4 patients with LSCD. Autologous conjunctival transplants combined with AM transplantation could be a practical option for treating bilateral LSCD in patients without symblepharon or severe keratinization.

Concise review: the coming of age of stem cell treatment for corneal surface damage

The cornea is a vital component of the eye because it provides approximately 70% of the refraction and focusing of incoming light. Being the outermost surface of the eye, it faces continuous stress from dryness, photodamage, infection, and injury; however, like the skin, the cornea regularly refreshes itself by shedding its epithelial cells, which are readily replaced, keeping the ocular surface stable and functional. This regular turnover of the corneal epithelial cells occurs through the stem cells in the limbus, an annular ring of a tissue surrounding the cornea, separating it from the sclera and the conjunctival membrane. The loss of this reserve of stem cells leads to a condition called limbal stem cell deficiency. Treatment for this disorder has evolved from transplanting whole limbal tissues to the affected eye to transplanting laboratory cultured limbal cells. This procedure is called cultivated limbal epithelial transplantation (CLET). Since its start in 1997, more than 1,000 CLET procedures have been reported from around the world, with varying degrees of success. In this paper, we compare the methods of cultivation and the outcomes and discuss some problem areas, use of other cells as substitutes for limbal epithelium, and various carrier materials used in transplantation. Our analysis suggests that CLET as a treatment for corneal surface damage has come of age. We also highlight a simpler procedure (simple limbal epithelial transplantation) that involves cultivation of limbal tissue in situ on the surface of the cornea in vivo and that has outcomes comparable to CLET.