Experts in Japan believe they may have unlocked the key to reversing one of the most life-changing conditions in the planet, and one which affects millions of people around the world – blindness.
Specialists at Doshisha University believe the key lies in regenerative medicine, or the use of specially grown tissues and cells to treat injuries and diseases, which have been successful in treating disorders of a number of organs in recent years, but not so the eyes.
In the background to the study, published in the July issue of The American Journal of Pathology, lead investigator Dr Noriko Koizumi explains how efforts to treat disorders of the corneal endothelium, a single cell layer on the inner surface of the cornea, with regenerative techniques have not been very effective.
However, Dr Koizumi, along with a group of scientists from the university's Department of Biomedical Engineering, Faculty of Life and Medical Sciences, has developed a method that enhances the adhesion of injected corneal endothelial cells (CECs), allowing for successful corneal transplantation to repair pathological dysfunctions.
Injected cultured CECs can be washed off by aqueous humour flow, resulting in poor adhesion of the cells injected onto the corneal tissue, with previous studies demonstrating that Rho-associated kinase (ROCK) signalling interferes with adhesion.
However, the Japanese scientists found that transplanting cultivated CECs in combination with a low-molecular weight compound that inhibits ROCK (ROCK inhibitor Y-27632) successfully achieved the recovery of corneal transparency.
Using rabbit cells, the researchers cultivated CECs in the lab and injected them into the anterior chamber of rabbit eyes with damaged corneal endothelia.
Based on the recovery of the corneal endothelial function, they found that when the cultivated cells were injected along with Y-27632, the rabbit corneas regained complete transparency 48 hours after injection.
In contrast, rabbit CECs injected without Y-27632 resulted in hazy and severely swollen corneas.
Secondary tests involving monkey CECs, which are more similar to those in humans, resulted in the primates also achieving the recovery of long-term corneal transparency with a monolayer of hexagonal cells, which suggests that cell adhesion modified by ROCK inhibitor may be an effective treatment for human corneal endothelial disorders.
Dr Koizumi concludes: "The novel strategy of using a cell-based therapy combined with a ROCK inhibitor may ultimately provide clinicians with a new therapeutic modality in regenerative medicine, not only for treatment of corneal endothelial dysfunctions, but also for a variety of pathological diseases."