Category: Health and Wellness
See interesting article below.
Fish oil to save preemies' sight?
Doctors try mimicking in utero conditions to prevent blindness The
Associated Press
Updated: 2:23 p.m. CT July 9, 2007
WASHINGTON - Perhaps nowhere in the body is the adage "you are what you eat"
so true as in your eyes, a link scientists are banking on in a novel bid to
save premature babies' vision.
Doctors are about to begin testing whether fish oils could prevent a disease
that can silently attack behind preemies' tiny eyelids, one that strikes
about 16,000 U.S. infants a year and blinds hundreds.
It's part of research into a trio of apparently eye-healthy compounds that
babies born too early miss absorbing from their mothers - research gaining
increasing attention as more and babies are born premature and at risk.
"We're trying to mimic what would happen in utero," explains Dr. Lois Smith,
an ophthalmologist at Children's Hospital Boston who is leading the work.
"Rather than give drugs, we're doing replacement treatment."
Preventing the disease - called retinopathy of prematurity, or ROP - is a
major goal, because there's no sure way to save vision once it strikes.
Laser therapy decreases but doesn't eliminate the chance of blindness, and
many babies who don't go blind still suffer serious damage.
It's not just an issue for preemies. The same abnormal growth of blood
vessels behind ROP triggers two leading causes of blindness in adults:
diabetic retinopathy and age-related macular degeneration. Already,
scientists are studying if these omega-3 fatty acids - the same kind touted
for heart health - could protect adult eyes, too.
Why might they? These diseases destroy the retina, the eye's innermost
layer, which harbors a higher percentage of certain fats than other organs.
Eat lots of salmon, rich in omega-3s, and your retina will show it. Eat
mostly hamburgers, and your retina will harbor more of a different fatty
acid, omega-6s. The retina's composition actually changes with diet.
Mothers pass omega-3s to their unborn children mostly during the third
trimester, when the eyes develop most rapidly. Preemies not only miss out on
some or all of that transfer, but omega-3s aren't added to the intravenous
feeding that many require, either.
Premature babies have still forming retinas; blood vessels necessary to
nourish them haven't finished growing. ROP forms when something spurs those
blood vessels to grow abnormally _ too many form, and they leak.
But do omega-3s play a role? Smith and colleagues at Harvard and the
National Eye Institute first turned to mice to find out.
They harmed the mice retinas in a way that mimics ROP, and then fed them
different foods: Half ate the rodent version of a typical Western diet, high
in omega-6s and low in omega-3s. Half ate the equivalent of a Japanese diet,
with a 2 percent higher omega-3 content.
That simple change cut in half the retinal disease among the
omega-3-nibbling mice, Smith reported last month in the journal Nature
Medicine.
More intriguing, the omega-3s didn't just block bad blood vessels from
forming. They also helped normal, healthy blood vessels grow. They appeared
to work by blocking well-known inflammation-causing pathways in the body -
while mice fed more of the omega-6s experienced extra inflammation.
Study will see if omega-3s help preemies Now, Smith is about to begin a
study in premature babies at her Boston hospital to see if adding omega-3s
to their IV feedings - feedings that today contain omega-6s instead -
decreases their risk of eye damage.
"This could be a very simple and safe treatment," says Dr. Rafael
Ufret-Vincenty, a retina specialist at the University of Texas Southwestern
Medical Center.
Indeed, omega-3s have long been known to be important for newborn brain
development; they're in breast milk and are added to some formulas for older
babies. When it comes to preemies' IV feeding, a version rich in omega-3s is
available in Germany but hasn't spread to North America, says Dr. Sylvain
Chemtob, an ROP specialist at Sainte-Justine University Health Centre in
Montreal.
"It makes a lot of biological sense," he says.
These are the same fish oils sold as over-the-counter dietary supplements
for heart health, and a nationwide study already is recruiting adults with
macular degeneration to test if high doses could slow their vision loss.
Drug combo to help growth?
For preemies, omega-3s aren't the only missing-from-mom player generating
attention. A drug combination sold to treat hormone-deficient children grow
taller is being studied, too - a growth hormone called IGF-1 and a "binding
protein" that helps regulate it.
Smith already knew babies with ROP lacked the growth hormone, but last month
she and colleagues at Sweden's University of Goteborg reported they also
have less binding protein than healthy babies. Studies in mice suggest that
protein helps ROP-stricken retinas develop more normally, the Swedish team
and University of Florida researchers reported, apparently by calling on
stem cells to help build strong blood vessels.
Stay tuned: the Swedish scientists have begun a pilot study of the drug
combo, Insmed Inc.'s Iplex, in preemies.