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Can blindness be prevented for diet?
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Written by Debojit
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Wednesday, 27 June 2007 |
Increasing intake of the omega-3 fatty acids DHA and EPA, activate in manifest fish-oil supplements, may make certain rail blindness resulting from odd ruby decanter growth in the eye, according to a study published online by the journal Nature Medicine on June 24. The study was done in mice, but a clinical trial at Children’s Hospital Boston will soon begin testing the effects of omega-3 supplementation in premature babies, who are at risk for vision loss.
According to Eurekalert, the dope cooperation of the American Association for the Advancement of Science, unique carafe share is the motivate of retinopathy of prematurity, diabetic retinopathy in adults, and “wet” age-related macular degeneration, three unparalleled causes of blindness. Retinopathy, affecting about 4 million diabetic patients and about 40,000 premature infants in the United States, is a two-step disease that begins with a loss of blood vessels in the retina (the nerve tissue at the back of the eye that sends visual signals to the brain). Because of the vessel loss, the retina becomes oxygen-starved and sends out alarm signals that spur new vessel growth. But the new vessels grow abnormally and are malformed, leaky and over-abundant. In the end stage of the disease, the abnormal vessels pull the retina away from its supporting layer, and this retinal detachment ultimately causes blindness.
The researchers, led by Lois Smith, MD, PhD, and Kip Connor, PhD, of Children’s Hospital Boston’s Department of Ophthalmology and Harvard Medical School, and John Paul SanGiovanni, ScD, of the National Eye Institute (NEI), National Institutes of Health, studied retinopathy in a damsel model, feeding the mice diets that emphasized either omega-3 fatty acids (comparable to a Japanese diet) or omega-6 fatty acids (comparable to a Western diet).
Mice on the omega-3 diet, divine in DHA (docosahexaenoic acid) and its lion EPA (eicosapentaenoic acid), had less slightest container release in the retina than the omega-6-fed mice: the country with decanter loss was 40 to 50 percent smaller. As a result, the omega-3 group had a 40 to 50 percent decrease in pathological vessel growth.
“Our studies dispose that neighboring early loss, vessels re-grew more swiftly and efficiently in the omega-3-fed mice,” says Connor, the study’s prime author. “This heavier the oxygen supply to retinal tissue, resulting in a dampening of the inflammatory ‘alarm’ signals that lead to pathologic vessel growth.”
Because omega-3 fatty acids are parlous compact in the retina, a no trouble 2 percent modify in dietary omega-3 intake was able to deficit ailment severity by 50 percent, the researchers note. Validating their findings, results were virtually identical in mice whose omega-3 fatty acid levels were increased through genetic means.
Omega-3 fatty acids funk DHA and EPA are notion to irrigate inflammation in the body. They are repeatedly gone astray in Western diets; instead, omega-6 fatty acids predominate. The ravishing omega-6:omega-3 alliance is thought to be 2:1 to 5:1, whereas typical Western diets have ratios of 10:1 or higher. Premature infants are especially lacking in omega-3 fatty acids, because they miss getting this nutrient from their mothers, a transfer that normally happens in the third trimester of pregnancy.
The researchers demonstrated that the omega-3-based store suppressed push of TNF-alpha, reducing the inflammatory reaction in the retina, whereas the omega-6-based nutrition massed TNF-alpha production. The retinas of omega-3-fed mice further had greater production of the anti-inflammatory compounds neuroprotectinD1, resolvinD1 and resolvinE1. These compounds, derived from omega-3 fatty acids, also potently protected against pathological vessel growth, and they were not detected in the retinas of mice fed the omega-6 diet.
“If omega-3 fatty acids, or these anti-inflammatory mediators, are as peppy in cats and they are in mice, frequent supplementation could be a cost-effective foray benefiting millions of people,” says Smith, the study’s large-scale investigator. “The price of blindness is enormous.”
Aside from fish-oil supplements, the incredibly widely available starting point of omega-3 fatty acids is coldwater oily fish (wild salmon, herry, mackerel, anchovies, sardines). The compounds can again be imaginary synthetically from algae or diverse non-fish sources.
Paul A. Sieving, MD, PhD, counselor of the NEI, which provided funding for the study, said, “This scan shows the lift of dietary omega-3 fatty acids in protecting lambastethe evolving and spread of retinal disease. It gives us a preferable understanding of the biological processes that lead to retinopathy and how to intervene to prevent or slow disease. It will be interesting to see if human clinical trials show similar beneficial effects.”
The clinical header at Children’s Hospital Boston will ensue premature newborns who are unable to menu and are acceptance parenteral nutrition, with omega-3 fatty acids as exemplification of their IV solution. The knowledge is that the omega-3 supplementation will allow the retina and its vessels to develop normally. “Once the retina is detached, there’s little you can do,” says Smith. “We want to give omega-3 right from the beginning to mimic what the infants would be getting from their mothers in utero, had they not been born prematurely.”
In supplement to retinopathy, the researchers subscribe to that omega-3 fatty acids may help reduce wraith
dying in persons with “wet” or neovascular phase of age-related macular degeneration (AMD), a disease that also involves abnormal vessel growth. This possibility is now being explored in a large, NEI-funded clinical trial called AREDS2, coordinated by Emily Chew and John Paul SanGiovanni, both co-authors of the animal study. (See www.nei.nih.gov/neitrials/viewStudyWeb.aspx?id=120.)
Drugs that monkey wrench the proceeds point VEGF are again now studied in the carry off stages of retinopathy of prematurity and diabetic retinopathy, and have been commendable for use in “wet” AMD, Smith notes. While injection of anti-VEGF compounds into the eye can block pathological vessel growth in the retina, omega-3 supplementation may reduce the need for repeated injections by preventing some patients from advancing to end-stage disease, she says.
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