Sleep apnea thickens blood vessels, increases heart disease risk

May 4, 2009

Obstructive sleep apnea, or periodic interruptions in breathing throughout the night, thickens sufferers' blood vessels. Moreover, it increases the risk of several forms of heart and vascular disease.

Emory researchers have identified the enzyme NADPH oxidase as important for the effects obstructive has on in the lung.

The results are published in the May 1 issue of the American Journal of Respiratory Cell and Molecular Biology. C. Michael Hart, professor of medicine at Emory University School of Medicine and Atlanta Veterans Affairs Medical Center, is senior author.

Obstructive sleep apnea is thought to affect one in every 50 women and one in every 25 men in the United States. Standard treatment involves a mechanical application of air pressure. Anything that blunts sleep apnea's effects on blood vessel physiology could reduce its impact on disease risk, Hart says.

Cyclically depriving mice of oxygen - researchers call this "chronic intermittent hypoxia" -- in a way that simulates obstructive sleep apnea gives them pulmonary hypertension. Pulmonary hypertension, which can be life threatening, is a condition in which the right side of the heart has trouble pumping blood because of resistance in the lung's blood vessels.

Chronic intermittent hypoxia forces the blood vessels in the lung to make more NADPH oxidase, Hart and his colleagues found. Mice that lack NADPH oxidase are immune to hypoxia's effects.

NADPH oxidase is a helpful enzyme because it is responsible for making superoxide, a reactive free radical that the immune system uses to kill bacteria. But superoxide also interferes with nitric oxide, a signal that allows blood vessels to relax.

Humans with mutations in genes for NADPH oxidase have recurrent bacterial infections because their ability to fight the bacteria is weakened. Thus Hart says inhibiting the NADPH oxidase enzyme in the entire body may be harmful, and he favors an indirect intervention.

"We think that strategies to lower NADPH oxidase expression induced by hypoxia may be useful in preventing hypoxia-induced pulmonary hypertension," says Hart.

More information: "The role of NADPH oxidase in chronic intermittent hypoxia-induced in mice." Nisbet R.E, et al. Am J Respir Cell Mol Biol. 40: 601-9 (2009).

Source: Emory University (news : web)

Explore further: Child sleep breathing problems studied

Related Stories

Recommended for you

New gene map reveals cancer's Achilles heel

November 25, 2015

Scientists have mapped out the genes that keep our cells alive, creating a long-awaited foothold for understanding how our genome works and which genes are crucial in disease like cancer.

Study suggests fish can experience 'emotional fever'

November 25, 2015

(—A small team of researchers from the U.K. and Spain has found via lab study that at least one type of fish is capable of experiencing 'emotional fever,' which suggests it may qualify as a sentient being. In their ...

How cells in the developing ear 'practice' hearing

November 25, 2015

Before the fluid of the middle ear drains and sound waves penetrate for the first time, the inner ear cells of newborn rodents practice for their big debut. Researchers at Johns Hopkins report they have figured out the molecular ...

How cells 'climb' to build fruit fly tracheas

November 25, 2015

Fruit fly windpipes are much more like human blood vessels than the entryway to human lungs. To create that intricate network, fly embryonic cells must sprout "fingers" and crawl into place. Now researchers at The Johns Hopkins ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.