Novel cornea transplant technique approved for first-in-man trial in India

A simple limbal epithelial transplantation procedure uses a synthetic biodegradable membrane to regenerate the cornea from small pieces of the patient's own cornea.

Issue: October 25, 2015

A novel transplant technique that delivers tissue to scarred corneas via a synthetic biodegradable membrane has been approved for a first-in-man safety trial by regulatory authorities in India, according to a press release from the University of Sheffield, U.K.

In a collaborative effort between the university and L.V. Prasad Eye Institute in Hyderabad, India, funded by the Wellcome Trust, 10 patients with vision loss due to corneal injury will be treated with the novel technique later this year, according to the release.

“L.V. Prasad Eye Institute has treated more than 800 patients using the cultured cell technique and they have good results, but that’s a drop in the ocean compared to the number of patients it could benefit. We’ve essentially simplified the technique to make it more accessible,” Sheila MacNeil, BSc, PhD, professor of tissue engineering in the University of Sheffield’s Department of Materials Science and Engineering, told Ocular Surgery News.

Simple limbal epithelial transplantation

In the simple limbal epithelial transplantation (SLET) procedure, a small piece of tissue containing the corneal stem cells from the patient’s unaffected eye will be cut into approximately eight to 10 pieces and lightly attached to a synthetic biodegradable membrane before being placed on the damaged eye.

The synthetic polylactic glycolic acid (PLGA) membrane, made of the same material as dissolvable sutures, provides a secure surface for the new, healthy corneal cells to grow out from the stem cells present in the limbal tissue pieces. The membrane dissolves after a few weeks, leaving the new cells attached to the eye and replacing the original scarred surface with the new corneal surface.

“The technique is not very difficult and can be taught to a well-trained cornea specialist within a few weeks,” Virender S. Sangwan, MD, director of the Center for Ocular Regeneration at the L.V. Prasad Eye Institute, told Ocular Surgery News.

Current procedure

In the current procedure, cells from the patient’s eye are cultured and grafted back to the scarred eye in a similar procedure, but using human amniotic membrane from donated placenta rather than the PLGA membrane to deliver the cells.

The concept of using small pieces of tissue rather than cultured cells was first tested by combining tissue explants with amniotic membrane. This has now been found to be successful, with more than 200 of these surgeries performed by trained doctors from the U.S., U.K., Australia, Canada, Colombia, Mexico and several other countries, Sangwan said.

“This technique of using tissue explants and amniotic membrane is easy to practice, and there are papers appearing in the literature now,” he said. “We are in the process of submitting our paper on the long-term outcome of SLET in 125 eyes, with a 78% success rate with a minimum follow-up of 1 year.”

Increased use of PLGA membrane

Although the use of amniotic membrane can be successful, fewer than 12 centers in the world offer this technique to patients. MacNeil hopes the PLGA membrane technique will be used in the existing centers as well as many more.

“I think it could actually take off very fast because the surgeons in the L.V. Prasad center are opinion leaders,” she said. “Within 2 to 3 years, this could become adopted, not just by the centers already culturing cells, but by all of the centers that would like to treat corneal regeneration and haven’t got the infrastructure to do the cell therapy.”

The primary endpoints of the first-in-man trial for the new technique will be to restore corneal phenotype with a transparent cornea and no recurrence of limbal stem cell deficiency, Sangwan said.

“Once we demonstrate the efficacy of the PLGA scaffold in a pilot trial, then it would likely become the technique of choice over a period of time for the following reasons: Surgeons don’t have to depend on laboratory-cultivated stem cells because this technique is expensive to establish and run, and very few surgeons have access to such facilities. Also, it has been designed so that the regulatory hassles once this is established will be minimal,” he said. “It is easy to learn, and for patients, it is more convenient.” – by Kristie L. Kahl

Reference:
First patient safety trials of new cornea transplant technique to take place in India. The University of Sheffield website. http://www.sheffield.ac.uk/faculty/engineering/news/corneatrials-1.482625. Published July 22, 2015. Accessed July 28, 2015.

For more information:
Sheila MacNeil, BSc, PhD, can be reached at the Kroto Research Institute, North Campus, University of Sheffield, Broad Lane, Sheffield, S3 7HQ, UK; email: s.macneil@sheffield.ac.uk.
Virender S. Sangwan, MD, can be reached at L.V. Prasad Eye Institute, Kallam Anji Reddy Campus, L.V. Prasad Marg, Banjara Hills, Hyderabad, 500 034, India; email: vsangwan@lvpei.org.

Disclosures: MacNeil and Sangwan report no relevant financial disclosures.