Children's ophthalmologist Lois Smith, the senior investigator on the study. (Photo: Whole Foods Market/Children Hospital/FIS)
Omega-3 could prevent blindness: study
Monday, February 14, 2011, 02:00 (GMT + 9)
A new study on omega-3 fatty acids divulges exactly how the compound prevents blindness in a mouse model of the disease. The follow-up study, from the same research team at Children's Hospital Boston, also supports findings that popular COX-inhibiting drugs like aspirin and NSAIDs do not interfere with omega-3’s benefit.
Published last week in Science Translational Medicine, the findings also suggest that omega-3's may help diabetes sufferers.
Retinopathy, a leading cause of blindness, impacts 4.1 million US denizens with diabetes and many premature infants. And another 7 million-plus people are victims of age-related macular degeneration (AMD), which also causes blindness.
Preventing these "neovascular" eye diseases with the supplementation of omega-3 fatty acids could allow for huge savings, said Children's ophthalmologist Lois Smith, MD, PhD, senior investigator on the study.
"The cost of omega-3 supplementation is about USD 10 a month, versus up to USD 4,000 a month for anti-VEGF therapy," she says, referring to certain drugs such used to treat AMD and diabetic retinopathy.
Omega-3 fatty acids appear in high concentrations in the retina and are often lacking in the diets of people in the West, where diets are often higher in omega-6 fatty acids.
Smith's previous study involved feeding mice diets rich in omega-3 fatty acids, and those mice had nearly 50 per cent less pathologic vessel growth in the retina than mice given diets rich in omega-6. The researchers also demonstrated that the omega-3 diet lessened inflammatory messaging in the eye.
The new study shows another way omega-3 protects vision - a direct effect on blood vessel growth that selectively encourages the development of healthy blood vessels and thwarts that of abnormal ones.
Moreover, Smith and her colleagues have isolated the specific compound from omega-3 fatty acids that produces these results in mice and the enzyme that generates it.
And finally, the findings showed that the enzyme 5-LOX acts by triggering the PPAR-gamma receptor - the same one that "glitazone" drugs such as Avandia, taken by patients with type 2 diabetes, activate to boost insulin sensitivity. As said drugs also amplify the risk for heart disease, increasing omega-3 consumption could be a safer way to treat patients with diabetes or pre-diabetes.
Smith is working with principal investigators at the National Eye Institute now running an ongoing multicentre trial of omega-3 supplements in patients with AMD that will continue until 2013. A previous retrospective study found that diets higher in fish were linked with a lower incidence of AMD.
As well, Smith is collaborating with a group in Sweden conducting a clinical trial of omega-3 fatty acids in premature infants. The scientists will measure infants' blood levels of omega-3 products and observe whether they develop retinopathy.
Harvard researcher and neurobiochemist Przemyslaw Sapieha, now of the Universite de Montreal's Maisonneuve Rosemont Hospital Research Centre, and Andreas Stahl were were co-first authors on the study.
- Diets rich in omega-3 could protect against macular degeneration
By Natalia Real