Gut bacteria influence major eye disease risk: study

Bacteria in the intestines may play an important role in determining if a person will develop blinding wet Age-related Macular Degeneration, a new study has found.
Age-related Macular Degeneration (AMD) is the leading cause of irreversible blindness in the industrialised world, affecting over 10 million individuals in North America, researchers at University of Montreal in Canada said.
AMD is characterised by a heightened immune response, sizable deposits of fat debris at the back of the eye called soft drusen (early AMD), destruction of nerve cells, and growth of new diseased blood vessels (wet AMD).
While only accounting for roughly 10 per cent of cases of AMD, wet AMD is the primary form leading to blindness.

Current treatments becomes less effective with time. It is therefore important to find new ways to prevent the onset of this debilitating disease.
While many studies on the genetics of AMD have identified several genes that predispose to AMD, no single gene can account for development of the disease.

Epidemiological data suggests that in men, overall abdominal obesity is the second most important environmental risk factor, after smoking, for progression to late-stage blinding AMD.
Until now, the mechanisms that underscore this observation remained ill defined.
Researchers found that changes in the bacterial communities of your gut, such as those brought on by a diet rich in fat, can cause long-term low-grade inflammation in your whole body and eventually promote diseases such as wet AMD.

Among the series of experiments conducted as part of this study, the group performed fecal transfers from mice receiving regular fat diets, compared to those receiving a high fat diet, and found a significant amelioration of wet AMD.
"Our study suggests that diets rich in fat alter the gut microbiome in a way that aggravates wet AMD, a vascular disease of the aging eye," said Przemyslaw Sapieha, professor at the University of Montreal.
"Influencing the types of microbes that reside in your gut either through diet or by other means may thus affect the chances of developing AMD and progression of this blinding disease," said Sapieha.

The study appears in the journal in EMBO Molecular Medicine.