Vision 20/20 : Une feuille de route pour la thérapie régénérative de l’œil

La version française sera disponible bientôt

This story was written by Timothy Gouldson, and originally published on McGill Health e-News.

Having recently returned from a visit to Iceland, one of his many stops on the international lecture circuit, Leonard Levin, MD, PhD, Professor, and former Chair, at McGill University’s Department of Ophthalmology and Visual Sciences, appreciates the benefit of having a roadmap.

In the challenge to bring patients treatments for irreversibly blinding eye diseases by regenerating retinal neurons (nerve cells), Dr. Levin and colleagues mapped out the direction vision scientists and clinicians will need to take in the near future. With significant contributions of researchers in North America and the National Eye Institute (NEI) in Bethesda, Md., the Translational Roadmap for Regenerative Therapies of Eye Disease is the product of those efforts.

“The authorship are among the leaders in this field,” says Dr. Levin, all either advising or part of the NEI. “The NEI initiated the Audacious Goals Initiative (AGI),” described as “an effort to push the boundaries of vision science and restore vision through regeneration of the retina.” Its stated goal is to replace cells of the retina that have been damaged by disease or injury, and to restore their connections to the visual centers of the brain.

Dr. Levin was appointed head of the executive scientific oversight committee for AGI imaging studies, to be able to visualize the regenerated cells, and then he joined the AGI steering committee. “And that’s how this paper in fact came about,” he says. “We saw how techniques for regeneration were maturing in the laboratory, and we realized we needed to start planning eventual translation to patients. This paper is the roadmap of how we can eventually get there.”

Because it relies heavily on stem cell therapy, regenerative medicine is complex. “Regenerating neurons is difficult because not only are you trying to keep neurons alive, you’re trying to make new neurons and get them to start to function, to connect to other neurons, including the brain. It’s never been done in a human. The work involves various kinds of stem cells, either embryonic stem cells or cells that are made stem-like by taking a normal cell and de-differentiating it to become a neuron,” Dr. Levin explains.

“This paper shows that the field has come to a point where we can start to talk about this. Ten or 20 years ago we wouldn’t really be able to do this because even then, the basic science wasn’t far enough along. Now, finally, the basic science has matured enough that we can start to talk about the clinical science. To quote Winston Churchill, ‘This is not the end. It is not even the beginning of the end.’ But it is, perhaps, the end of the beginning,” Dr. Levin added.

For the many millions who suffer from irreversible eye diseases, caused by glaucoma, macular degeneration, and many others, the roadmap means hope. “I take care of patients with optic nerve diseases, which are one of those irreversible diseases. There’s a special kind of stroke of the optic nerve where they lose significant vision, permanently. In some patients they can become completely blind in the course of a day. You can imagine how this suddenly changes their life. With this roadmap we finally can start talking about how to eventually help these patients see again.”

The roadmap addresses the main issues in regenerative eye therapy including: safety measures; disease progression; and the transition to clinical trials. The nature of stem cell therapy also raises important ethical issues. “There’s a possibility, when the trials are started in people, that one of the stem cells could go awry and become a teratoma, a type of a tumor, or that other aspects of the treatment could make their existing vision worse,” Dr. Levin points out. “So it is important that the very first trials be planned meticulously and with the utmost regard for patient safety.”

The prognosis? “If the laboratory findings can be translated to human use, it would revolutionize the lives of millions of people worldwide. This document provides a roadmap for moving these exciting studies from the laboratory to the clinic,” Dr. Levin said.