Glaucoma is one of the causes that causes blindness, and it’s a common issue in Canada. But what causes glaucoma?
U.S. researchers found new information that shows glaucoma might be an autoimmune disease, where the immune system attacks the cells inside the eye and leads to vision loss.
Until now, experts knew that the pressure build-up in the eye is caused by a fluid that circulates through the eye. What they don’t know is what triggers the fluid build-up. If there is an increase in pressure, it starts damaging the nerve cells inside the retina. The nerve cells that are damaged cannot be replaced, causing permanent vision loss.
The disease can affect any person, but it’s more common in old people.
Researchers from the Massachusetts Institute of Technology (MIT) and Massachusetts Eye and Ear said that there could be an answer to what causes glaucoma: our immune system is to blame.
The Culprit: T Cells
The researchers found that a single treatment for glaucoma (which lowers the pressure in the eye) is the only way to slow the disease in some individuals. In others, the treatment has not stopped the disease from progressing.
The MIT team wondered if eye pressure triggers something which continues to damage the retina. To see if their theory was correct, they conducted some observations on mice with glaucoma, looking at the immune cells in the mice’s retinas. Surprisingly, the team found that the white blood cells that help with an immune response – the T cells, were inside the retina.
Researchers knew that the blood-retina barrier (that helps suppress inflammation in the eye) should block T cells from entering, but when the pressure in the eye increases, T cells get through the barrier.
With this theory proved, the team started experimenting on mice that didn’t have T cells. They increased the pressure in the eyes of these mice to see if it causes damage and then triggers the disease. Surprisingly, the pressure only caused small damage to the retina, and the disease did not progress after eye pressure was back to normal.
This meant that T cells targeted proteins which help them respond to injury or stress – the heat shock proteins. Researchers believe that the T cells interacted in the past with bacterial heat shock proteins, making them sensitive and start attacking the proteins in the eye.
On a small human trial, the researchers checked their findings on 18 patients with glaucoma. They discovered that the patients had elevated levels of T cells compared to healthy people. Researchers discovered that the same process happens in humans.
The last part of the study was again conducted on mice to see if they would develop the disease after being bred in a germ-free environment – and they did not develop glaucoma.
The author of the study, MIT professor of biology Jianzhu Chen concludes that their study is the first step in discovering a “new approach to prevent and treat glaucoma.”
Rex Austinwas born and raised in Thunder Bay Ontario on the shores of Lake Superior. Apart from running his own podcast (Ice Fishing And Other “Cool” Things), he spends his time canoeing and backpacking in Northern Ontario.. As a journalist Rex has published stories for Global News (Thunder Bay) we well as Buzz Feed and Joystiq. As a contributor to Great Lakes Ledger, Rex most covers science and health stories. Contact Rexhere