A NEW
DISCOVERY ABOUT THE WAY SLEEP APNEA MAY RAISE THE RISK OF HEART DIEASE AND HOW
STATIN MAY REDUCE THE RISK.
MedlinePlus: “Sleep apnea
is a common disorder that involves irregular breathing while asleep, with
oxygen intake dropping frequently for brief periods. The condition can triple a
person's risk of stroke, high blood pressure and other heart problems, said
study author Dr. Sanja Jelic, an associate professor of medicine at Columbia
University Medical Center in New York City.
Statins such as Crestor
(rosuvastatin) and Lipitor (atorvastatin) are already taken by millions of
Americans to reduce their risk of heart disease.
"If the beneficial
effects of statins on blood vessel health in patients with obstructive sleep
apnea is confirmed in larger clinical trials, obstructive sleep apnea may
become an indication for statin therapy," Jelic said.
The findings were
published online Jan. 6 in the journal Science Translational Medicine.
In the small, laboratory
study, researchers closely examined endothelial cells, which line the inside of
blood vessels. They looked at endothelial cells from 76 adults with obstructive
sleep apnea and 52 adults without sleep apnea. The adults were similar in terms
of body fat percentage, daytime sleepiness symptoms, blood pressure and
underlying health conditions.
The scientists found that
a particular protein was in different places in the cells of those with sleep
apnea compared to the cells of those without the disorder. The protein, called
CD59, normally stays on the surface of endothelial cells to protect them from
part of the body's immune system, according to background notes with the study.
But in patients with sleep apnea, the protein was often inside the cells.
A series of experiments
showed that the cells pull the protein inside them when oxygen levels drop. The
cells then become vulnerable to inflammation, which can contribute to high
blood pressure, the researchers said.
"Chronic inflammation
of the blood vessels contributes to increased cardiovascular risk, such as
heart attack, stroke or heart failure, in patients with obstructive sleep
apnea," Jelic said.
How much protein the cells
pulled inside them depended on how much cholesterol --- the waxy, fat-like
substance found in all cells of the body -- was present. Statins stopped the
cells from bringing the protein inside them, the investigators found.
Experts agreed, however,
that people with sleep apnea should not seek statin prescriptions just yet
since these findings were limited to the lab.
Dr. Sarah Samaan, a
cardiologist at the Baylor Heart Hospital in Plano, Texas, said: "This is
basic science research, not a clinical study. So we don't know specifically
what degree of reduction in heart risk statins might provide for sleep apnea
patients without other risk factors.
"Although statins
don't treat sleep apnea, they may help reduce the dangerous consequences sleep
apnea can have on the heart," she added.
The primary treatment for
obstructive sleep apnea is continuous positive airway pressure (CPAP),
delivered through a mask worn at night, Spencer said. Weight loss and a healthy
lifestyle can also help treat sleep apnea."
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