Previous research has shown that omega-3 fatty acids – commonly found in fish oil – can prevent retinopathy, a major form of blindness that affects people with diabetes and premature babies, in a mouse model of the disease.
Now a follow-up study, from the same research team at Children`s Hospital Boston, has revealed how exactly omega-3 fatty acids help prevent several forms of blindness.
It also provides reassurance that widely used COX-inhibiting drugs like aspirin and NSAIDs do not negate their benefit.
The results showed that omega-3 fatty acids could prevent eye blindness such as retinopathy, caused by the proliferation of tortuous, leaky blood vessels in the retina, and age-related macular degeneration (AMD), caused by abnormal growth of blood vessels.
Previous research by Children`s Hospital ophthalmologist Lois Smith and senior investigator of the new study had shown that mice fed diets rich in omega-3s had 50 percent less pathologic vessel growth in their retina than mice fed diets rich in omega-6 fatty acids.
In their new study, Smith and her colleagues documented another protective mechanism - a direct effect on blood vessel growth (angiogenesis) that selectively promotes the growth of healthy blood vessels and inhibits the growth of abnormal vessels.
They isolated the specific compound from omega-3 fatty acids that has these beneficial effects in mice (a metabolite of the omega-3 fatty acid DHA, known as 4-HDHA), and the enzyme that produces it (5-lipoxygenase, or 5-LOX).
The researchers also found that COX enzymes are not involved in omega-3 breakdown, suggesting drugs such as aspirin or NSAIDs do not affect the benefits of omega-3.
"This is important for people with diabetes, who often take aspirin to prevent heart disease, and also for elderly people with AMD who have a propensity for heart disease," said Smith.
Smith is currently working alongside the US National Eye Institute, which is conducting a trial of omega-3 supplements in patients with advanced macular degeneration, expected to conclude in 2013.
The findings are published in the current issue of Science Translational Medicine .