Clinical Study on the Treatment of Mixed Component Cornea for High Risk Keratoplasty

Study Overview
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Brief Summary
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Because of the immunologically privileged nature of the cornea, the graft rejection rate is less than 10% for low-risk keratoplasty. But when the cornea performed 2 or more quadrants of corneal neovascularization after ocular trauma or infection, the graft rejection rate is more than 65%, it is called high-risk keratoplasty. This study will observe the graft survival of high-risk corneal transplantation using mixed component cornea from different donors.

Detailed Description
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Ocular trauma or infection lead to corneal limbal stem cell deficiency and central corneal opacification which could only be treated by central penetrating keratoplasty and limbal transplantation, but the rejection rate is very high. In clinical, we found that limbal transplantation combined with central penetrating keratoplasty from different donors can keep the graft transparent for a long time, this result also be found in organ transplantation, multiple donor organ transplantation could reduce rejection risk in liver and kidney transplantation. Therefore, it is speculated that there are different MHC antigens from different donors, which cause different reactions after transplantation. Because there are a large number of Langerhans cells， abundant blood vessels and lymphatic in the limbal, so the rejection occurs early and severely. Continuous and intense limbal rejection leads to the depletion of recipient T cells, lead to the immune tolerance of another donor's central corneal tissue. In this project, central penetrating keratoplasty and limbal transplantation from different donors will be carried out and the graft survival of high-risk corneal transplantation will be observed in clinical, to find a new method for high-risk corneal transplant patients.

Official Title
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Suppression of Graft Rejection Using Mixed Component Cornea in the High-risk Keratoplasty，A Randomized Controlled Trial.

Conditions
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Corneal Transplantation

Intervention / Treatment
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* Procedure: Limbal transplantation combined with central penetrating keratoplasty
* Procedure: Limbal transplantation combined with central penetrating keratoplasty


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Central corneal opacity involving full layer Corneal neovascularization in two or more quadrants Patients must be willing and able to return for scheduled follow-up examinations for 12 months after surgery Ages：18 -70 Years Exclusion Criteria: Central corneal opacity not involving the endothelial layer Less than two quadrants of corneal neovascularization History of Stevens-Johnson syndrome or Sjogren's syndrome Severe eyelid and conjunctival scar Loss of vision in contralateral eye Pregnant and lactating women

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
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Single graft corneal transplantation<br>Limbal transplantation combined with central penetrating keratoplasty from single donors. | Procedure: Limbal transplantation combined with central penetrating keratoplasty<br>* Limbal transplantation combined with central penetrating keratoplasty with single donor cornea<br>|
| Experimental: Dual graft corneal transplantation<br>Limbal transplantation combined with central penetrating keratoplasty from different donors. | Procedure: Limbal transplantation combined with central penetrating keratoplasty<br>* Limbal transplantation combined with central penetrating keratoplasty with mixed component cornea<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The rate of corneal graft rejection at 12 months | The rejection index of corneal transplantation will be observed by slit lamp after surgery | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The changes of best corrected visual acuity | Best corrected visual acuity in different point will be compared with preoperative | Before surgery, 1 week, 1 month, 3 months, 6 months, 12 months | 
| The changes of corneal thickness depth | Corneal thickness depth will be measured by anterior segmental OCT and compared with preoperative | baseline (Before surgery), 1 week, 1 month, 3 months, 6 months, 12 months | 
| Reconstruction of corneal limbal | Confocal microscopy will be used to define whether the structure of corneal limbal has reconstructed | baseline (Before surgery), 1 week, 1 month, 3 months, 6 months, 12 months | 
| Endothelial Cell Density | Endothelial Cell Density will be measured by specular microscope to evaluate the loss of endothelial cells | baseline (Before surgery), 1 week, 1 month, 3 months, 6 months, 12 months | 
| The rate of presence of goblet cells containing conjunctival epithelium on the corneal surface by impression cytology | Detects whether conjunctival epithelial and goblet cells have invaded the corneal surface by impression cytology, to observe the reconstruction of limbal function | baseline (Before surgery), 1 week, 1 month, 3 months, 6 months, 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Penetrating keratoplasty, High-risk corneal transplantation, Limbal transplantation