Corneal Epithelium Repair and Therapy Using Autologous Limbal Stem Cell Transplantation

Sun Yat-sen University

Status and phase: Unknown; Phase 2; Phase 1

Conditions: Myopia; Corneal Disease; Pterygium; Hyperopia

Treatments: Drug: Levofloxacin; Procedure: LSCs and amniotic membrane (Modified Technique); Procedure: Amniotic membrane only (Traditional Technique); Procedure: PRK, LSCs, and amniotic membrane (Modified Technique); Drug: Betamethasone; Drug: Limbal stem cells (LSCs); Procedure: PRK only (Traditional Technique)

Study type: Interventional

Funder types: Other

Identifiers

NCT02148016

2013SKL005

Details and patient eligibility

About

Corneal disease is a leading cause of blindness in the world. A shortage of corneal donor tissue has prevented many patients from regaining vision. Additionally, refractive error such as myopia is a major cause of impaired visual function worldwide. Although refractive error is correctable by procedures that modify the refractive power of the cornea, these procedures often weaken corneal integrity and have risk of complications. This study aims to evaluate the safety and efficacy of corneal surface epithelium repair and regeneration in the treatment of corneal surface diseases and refractive error using autologous limbal stem cell transplantation.

Full description

The corneal surface is comprised of a unique type of non-keratinized epithelial cell. These cells are arranged in an orderly fashion, which is essential for vision by maintaining the transparency of the visual axis.

Chemical injury and pterygia may damage the limbus, the zone between the cornea and the bulbar conjunctiva, and cause limbal stem cell (LSC) deficiency. They represent major treatable causes of vision loss worldwide. A shortage of corneal donor tissue prevents many patients from regaining vision, necessitating new treatment strategies to circumvent this limitation. Transplantation of stem cells represents an appealing therapeutic strategy in regenerative medicine, and the use of endogenous stem cells provides a possible solution to the problem of immune rejection.

Currently, LASIK (laser-assisted in situ keratomileusis) is the most commonly performed laser vision correction procedure in the world (over 10 million surgeries each year); however, it has a major disadvantage in that it weakens corneal integrity and structure and predisposes to complications such as keratectasia or keratoconus (bulging of the cornea) and vision loss. An alternative is photo-refractive keratectomy (PRK), which removes the corneal epithelium and anterior stroma while minimizing the incidence of keratectasia or keratoconus. The primary drawbacks of PRK are that it requires a longer recovery time (the corneal epithelium must regenerate from the patient's own LSCs) and may result in blurry vision and pain due to corneal pain nerve fiber exposure after removal of the epithelium. Coverage of exposed corneal stroma tissue immediately after surgery with LSC-derived corneal epithelial cells will solve this key bottleneck and make laser eye surgery safer and more comfortable for millions of people.

It is known that corneal renewal and repair are mediated by stem cells in the limbus. Autologous LSC transplantation has been reported previously (Rama et al.). However, mouse feeder cells were required to expand LSCs in culture. We have successfully developed a feeder-free, chemically defined medium in which to expand LSCs. These expanded LSCs can repair and regenerate corneal surfaces (Ouyang et al., in press).

Hypothesis: The trial will demonstrate whether a new technique, transplantation of LSCs expanded from limbal tissue of the uninjured eye, can improve the visual function of patients with unilateral corneal ocular surface disease. In addition, it will show whether there is more rapid recovery and improved visual outcomes following PRK if expanded LSCs are used to cover the cornea. The study will also compare the incidence of complications and characterize visual outcomes in patients treated with the new technique versus the control technique.

Enrollment: 30 estimated patients

Sex: All

Ages: 10 to 70 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Monocular corneal chemical injury or pterygium, or refractive error greater than +/- 2D
• Informed consent signed by patient or legal guardian

Exclusion criteria

• Patients with a history of corneal perforation or surgery
• Patients with other eye diseases
• Patients with a history of severe cardiovascular, liver, kidney, endocrine, and hematopoietic disease, diabetes, or immune deficiency disorders
• Pregnant or lactating women
• Patients who are participating in other clinical trials
• Patients with a history of mental illness who are unable to give informed consent or follow up according to the study protocol.

Trial design

Primary purpose: Treatment

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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30 participants in 4 patient groups

LSCs and amniotic membrane (Modified Technique)

Experimental group

Description:

Limbal stem cells (LSCs) from the contralateral eye will be harvested and expanded in feeder-free, chemically defined media for one week on a collagen-coated contact lens. The LSCs on contact lens will be transplanted onto a corneal surface in vivo, following removal of scar tissue due to chemical injury or pterygium. The contact lens will then be covered with amniotic membrane to secure it in place. The eye will be treated with antibiotics (levofloxacin) and steroids (betamethasone), and then patched.

Treatment:

Procedure: LSCs and amniotic membrane (Modified Technique)

Drug: Levofloxacin

Drug: Betamethasone

Amniotic membrane only (Traditional Technique)

Active Comparator group

Description:

Amniotic membrane alone will be used to cover the corneal surface, after removal of scar tissue from a chemical injury or pterygium.

Treatment:

Procedure: Amniotic membrane only (Traditional Technique)

PRK, LSCs, and amniotic membrane (Modified Technique)

Experimental group

Description:

Limbal stem cells (LSCs) from the contralateral eye will be harvested and expanded in feeder-free, chemically defined media for one week on a collagen-coated contact lens. The LSCs on contact lens will be transplanted onto a corneal surface in vivo, following photo-refractive keratectomy (PRK). The contact lens will then be covered with amniotic membrane to secure it in place. The eye will be treated with antibiotics (levofloxacin) and steroids (betamethasone), and then patched.

Treatment:

Drug: Levofloxacin

Drug: Betamethasone

Procedure: PRK, LSCs, and amniotic membrane (Modified Technique)

Drug: Limbal stem cells (LSCs)

PRK only (Traditional Technique)

Active Comparator group

Description:

PRK alone will be performed.

Treatment:

Procedure: PRK only (Traditional Technique)