A single X-ray treatment of an individual eye can apparently provide mice with lifelong protection against glaucoma.
The disease, a leading cause of blindness, involves damage to the optic nerve through complex, poorly understood processes. It affects more than 4 million Americans.
Scientists led by researchers at The Jackson Laboratory report on their findings about the X-ray treatment in an article published Monday in the open-access Journal of Clinical Investigation. They came to the new treatment after the accidental discovery a decade ago that a single dose of whole-body irradiation coupled with bone marrow transfer conveyed protection against glaucoma. Japanese survivors of the World War II atomic bombs also exhibited low rates of glaucoma.
The Jackson Laboratory is an independent, nonprofit organization that studies mammalian genetics. It used a gene expression study to learn that glaucoma involves stresses that send a class of immune cells called monocytes into the optic nerve and retina. The response initially helps protect the eye, but the monocytes cause inflammation that eventually damages the nerve.
The radiation treatment blocks—somewhat mysteriously—the monocytes from entering the eye. As the study says:
It is not clear how radiation suppresses invasion of monocytes in the long term, including still-unborn monocytes that are remotely located.
The findings offer the possibility of a simple but highly effective new preventive treatment for glaucoma. However, they also call into question what we thought we knew about the disease.
“Our data support what we believe to be a new model,” the study says, “in which monocytes are essential for glaucomatous damage and suggest that glaucoma is primarily a neuroinflammatory disease.”
Currently, glaucoma detection and treatment focus on elevated pressure inside the eye, the best-known risk factor for the disease. But the radiation treatment blocked glaucoma even in mice with high intraocular pressure.
Obviously, as lead author Gareth Howell, PhD, says in a Jackson Lab news release, “More work is needed to fully understand how the radiation confers long-term protection.”
Related seminar: Neuro & Musculoskeletal Imaging