Glaucoma, one of the most common eye diseases, is the leading cause of blindness. Despite existing treatments, some patients still lose their vision. Recent research in China suggests a role for immune cells migrating from the digestive tract to the eye in the progression of glaucoma.
Glaucoma is a group of neurodegenerative diseases that cause the loss of retinal ganglion cells (RGCs) responsible for transmitting visual information to the brain. The optic nerve, which is made up of the axons of these cells, relays information to the visual cortex of the brain for processing. Glaucoma is incurable and treatment is aimed at stopping the progression of the disease.
Recent studies have shown that immune system T cells may play a role in glaucoma damage, but the mechanism has remained unclear. Clinical immunologists from the University of Electronic Science and Technology in China found that a subset of CD4+ T cells express the receptor integrin β7, which allows them to enter the retina via the MAdCAM-1 protein.
The researchers tested blood samples from glaucoma patients and healthy individuals. They found a significantly higher percentage of β7-expressing CD4+ T cells in glaucoma patients, as well as a correlation between the number of these cells and the severity of the disease.
To confirm their findings, the researchers used a glaucoma model in mice. They found that in order for β7+ CD4+ T cells to gain access to the retina, they must pass through the intestine. These cells were reprogrammed in the gut and used the β7 integrin as a “license” to return to the bloodstream and travel to the retina.
The results of this study emphasize the importance of the gut-retina axis in the pathogenesis of glaucoma and may provide a basis for the development of new therapeutic strategies.
Professor John Smith, a glaucomatologist at the University of Oxford, notes: “This is an exciting study that helps us to better understand the mechanisms of glaucoma development. The results point to a role for immune cells in the progression of the disease and may contribute to the development of new therapies.”