Results of a phase II clinical trial released today in STEM CELLS Translational Medicine (SCTM) indicate that a limbal stem cell (LSC) transplantation is superior to a tissue graft in treating limbal stem cell deficiency syndrome (LSCD).
This could result in a new and better treatment for LSCD, a condition that is mostly caused by burns to the eye. In its most extreme form, LSCD results in severe vision loss or total blindness. Until recently, the main treatment for this condition was a limbal tissue transplant using tissue from either the patient, a relative or a cadaver — a treatment that carried with it a high risk of rejection and a lifetime of immunosuppressant drugs for the patient.
However, recent advances in cell therapy techniques have introduced stem cell transplantation as a possible way to deal with LSCD. The study reported on in SCTM, conducted by a team of researchers from Centre Hospitalier National d’Ophtalmologie des 15-20 and the Etablissement Français du Sang (EFS), was designed to compare the efficiency and safety of transplantation of LSCs cultured on human amniotic membrane to limbal tissue transplantation.
To do so, the researchers recruited 14 patients with stage 3 LSCD. They treated seven with autologous (their own) limbal stem cells (autoLSC) and seven with allogeneic (donated) stem cells (alloLSC). They followed the patients for an average of 72 months and then compared the results of their treatment to a retrospective control group of 16 people who had received either an autologous or allogenic LSC graft at Centre Hospitalier between 1993 and 2014.
“What we found was that, at the last follow-up visit, visual acuity was significantly better in the autoLSC and autologous limbal tissue (autoLT) groups than in the allogeneic limbal tissue (alloLT) and alloLSC groups. In fact, the allogeneic grafts featured low success rate and serious adverse events,” said Vincent Borderie, M.D., Ph.D., the study’s lead investigator.
“Visual acuity improved by 9.2 lines for autoLSC and 3.3 lines for autoLT,” he added. “And while both the autoLSC and autoLT patients were similar in terms of treatment efficiency — both showed high long-term survival — autoLSC transplantation appears to be safer than autoLT transplantation.”
Specifically, in the autoLSC group, no eyes were found to have decreased vision at last follow up, adverse events were both uncommon and minor, and the size of the limbal biopsy taken in the healthy contralateral donor eye was very small.
“Conversely,” Dr. Borderie said, “in the autoLT group, two out of nine eyes had decreased vision at last follow up, adverse events were common and potentially sight-threatening, and the size of the limbal biopsy taken in the healthy contralateral donor eye was much larger.
“These findings are interesting and useful in considering future cell-based therapies to treat LSC.”
“This study shows that using the patients’ own stem cells to treat a condition that causes severe vision loss or total blindness resulted in vision improvement and was safe to use,” said Anthony Atala, M.D., Editor-in-Chief of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine. “These findings are significant, as the cell-based therapy had better outcomes than tissue grafting in the treatment of limbal stem cell deficiency syndrome.”