Labial Mucosal Epithelium Grafting for Corneal Limbus Substitution

Study Overview
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Brief Summary
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Earlier approaches for cornea reepithelization in patients with bilateral LSCD included allogeneic corneal limbus grafting from postmortem donor or livingrelated relatives with concomitant systemic immunosuppression (Cheung and Holland, 2017) and cultivated oral mucosal epithelial transplantation (COMET) (Nishida et al., 2004). The novel surgical technique for corneal re-epithelization were described by Liu et al. (2011) and Choe et al. (2019). In both clinical studies, the autologous labial mucosal epithelium graft was transplanted as a surrogate corneal limbus for purpose of treatment the LSCD. Authors reported positive outcomes in terms of anatomical success and corneal status improvement. The purpose of the study is to evaluate the feasibility of the novel surgical intervention in clinical use.

Detailed Description
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Earlier approaches for cornea reepithelization in patients with bilateral LSCD included allogeneic corneal limbus grafting from postmortem donor or livingrelated relatives with concomitant systemic immunosuppression (Cheung and Holland, 2017) and cultivated oral mucosal epithelial transplantation (COMET) (Nishida et al., 2004). The novel surgical technique for corneal re-epithelization were described by Liu et al. (2011) and Choe et al. (2019). In both clinical studies, the autologous labial mucosal epithelium graft was transplanted as a surrogate corneal limbus for purpose of treatment the LSCD. Authors reported positive outcomes in terms of anatomical success and corneal status improvement. Lip oral mucosa is a promising autologous source of epithelial cell for the trial because it has similar histological characteristic as the normal corneal. In particular, lip oral mucosal epithelium is stratified squamous and nonkeratinized. The indicated histological and molecular features of the lip oral mucosal epithelium predetermined the use of labial mucosal epithelial graft for treatment patients with bilateral LSCD. The purpose of the study is to confirm the validity of the hypothesis about the possibility of re-epithelialization diseased cornea using labial mucosal epithelium graft as a surrogate limbus in patients with bilateral LSCD.

Official Title
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Efficiency and Safety of Labial Mucosal Epithelium Grafting for Corneal Reepithelization in Patients With Bilateral Non-immunogenic Limbal Stem Cell Deficiency

Conditions
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Limbal Stem-cell Deficiency

Intervention / Treatment
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* Procedure: Labial mucosal epithelium grafting for corneal limbus substitution


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Man or woman 18 years and older. Signed informed consent, given by the participant or his/her legal representative. Ability to understand Russian spoken and written language. Sanitated oral cavity. Bilateral limbal stem cell deficiency diagnosed by two or more symptoms during slit-lamp examination: corneal conjunctivalization, absence of palisades of Vogt, superficial corneal neovascularization, recurrent or persistent corneal epithelium erosion. Bilateral limbal stem cell deficiency non-immunogenic etiology (burns, irradiation, contact lens related, etc.). Best-corrected visual acuity less than 0.3 (6/18 Snellen chart) Intraocular pressure in normal range. Schirmer's test I more than 5 mm. Exclusion Criteria: Inability to give signed informed consent. Age under 18 years. Pregnancy and/or breastfeeding. Hormonal contraceptives intake. History of allergic reactions to antibiotics, glucocorticosteroids, remedies for treatment dry eye syndrome, medications for local and general anesthesia. Participation in other clinical trials. Systemic immunosuppression intake. Diagnosed neoplastic process or treatment for it. Positive tests for infectious: HIV, syphilis, Hepatitis B, Hepatitis C. Any medical, psychiatric and/or condition, including cachexia, or social conditions that the investigator believes would interfere with or contraindicate adherence to the research protocol or the ability to provide signed informed consent. Immune-mediated limbal stem cell deficiency (Stevens-Johnson syndrome, ocular cicatricial pemphigoid and other.), unknown and/or inherited etiology. Best-corrected visual acuity more than 0.3 (6/18 Snellen chart) Ocular burns earlier than 12 months. Keratoplasty earlier than 12 months. Limbal grafting (from postmortem or living-related donors). Keratoprosthetic device or history of its implantation. Cellular therapy for treatment of limbal stem cell deficiency. Cellular transplantation for treatment of limbal stem cell deficiency. Active ophthalmic infection. Symblepharon, ectropion, trichiasis, lagophthalmos and/or other lid and/or conjunctival fornixes abnormalities. Surgery on ocular adnexa earlier than 9 months. Corneal stromal thickness less than 300 mkm. Dry eye with Schirmer test I less than 5 mm and/or keratinized ocular surface. Uncontrolled glaucoma and/or presents of a glaucoma drainage device. Retinal defunctioning (no light perception and/or retinal detachment). Absence of the electric activity of the optic nerve and/or retina.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Labial mucosa epithelium grafting for corneal limbus substitution.<br>Surgery for treating limbal stem cell deficiency using a strip of the lip oral mucosa with trimmed off the substantia propria and grafted as a circular corneal limbus substitute. | Procedure: Labial mucosal epithelium grafting for corneal limbus substitution<br>* Labial mucosa epithelium grafting for corneal limbus substitution will be used to treat limbal stem cell deficiency by way of corneal surface re-epithelization<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Anatomical success | Presence of a stable epithelium on the cornea and absence of conjunctivalization in the visual axis of the recipient eye | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of participants with improvement in corneal status | A composite score for the corneal disease status (Campbell et. al., 2019) of the patients will be obtained throughout the study using the following 4 criteria in points according to the grades (grade 0, grade 1 - mild, grade 2 - moderate, grade 3 - severe): corneal staining: 0 - no punctuate staining, 1 - superficial punctate keratopathy (SPK) less than 50% of the corneal surface, 2 - SPK more than 50% of the corneal surface, 3 - epithelial defect; conjunctivalisation: 0 - absent, 1 - <25% of corneal surface, 2 - 25-50% of corneal surface, 3 - >50% of corneal surface; corneal neovascularization: 0 - absent, 1 - confined to corneal periphery, 2 - extending to pupil margin, 3 - extending beyond pupil margin into central cornea; corneal opacification: 0 - clear cornea, iris details clearly visualized, 1 - partial obscuration of iris details, 2 - iris details poorly seen with pupil margin just visible, 3 - complete obscuration of iris and pupil details. | 12 months | 
| Functional success | Improvement in near and/or distance visual acuity | 12 months | 
| Rate of complications | Intraoperative and postoperative complications on the recipient eye | 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Limbal Stem Cell Deficiency