Gene Variant Seems to Guard Against Asthma, COPD

WEDNESDAY Dec. 16, 2009 -- A gene variant that plays a role in inflammation seems to protect the lungs of children with asthma as well as adults who smoke.

Researchers also found that adult smokers with this variant of the MMP12 gene had a lower risk of developing chronic obstructive pulmonary disease (COPD), a progressive condition often brought on by smoking.

"The gene seems to be protective of the lungs in both asthma and COPD," said Dr. Norman Edelman, chief medical officer of the American Lung Association.

Any new gene identified raises the hope that it will provide ways to prevent or treat the disease to which it is allied and this is no exception.

"Levels of the MMP12 gene may impact the quality of life for those individuals with asthma and COPD, and may allow us to come up with potential therapeutic approaches," added Jeffrey Cirillo, professor of microbial and molecular pathogenesis at Texas A&M Health Science Center College of Medicine in College Station. "By understanding more about this specific gene we can find ways to induce or oppress that protein expression in the lungs."

"The real question is not why people who smoke get COPD. We kind of know the answer to that. The question is why do people who don't smoke get COPD," added Edelman. "If we understood that, we could find ways to reverse it and protect people."

The MMP12 gene has been implicated in the development of emphysema in mice that are exposed to smoke, suggesting that the gene may also be important in the onset of emphysema in humans. The gene is also linked with other genes involved in asthma.

This information, combined with the fact that factors that can cause the onset of asthma in children are also involved with how well your lungs function in adulthood spurred investigators to undertake this study.

Dr. Juan C. Celedon, an associate professor of medicine at Brigham and Women's Hospital and Harvard Medical School in Boston and his colleagues looked at seven different groups of people, in all comprising 8,300 children and adults.

A variant of MMP12 was associated with better lung function in children with asthma.

In adults, the variant led to better lung function in adult smokers and reduced the risk of COPD in former or current smokers.

The findings, published online Dec. 16 in the New England Journal of Medicine, also shed new light on the connections between asthma and COPD.

"This suggests that there are some genes that may influence both asthma and COPD, so that for a subgroup of people there may be common determinants," said study senior author Celedon.

"There is certainly overlapping in that how you get asthma and how you get COPD is related and probably very closely related," Cirillo said. "That's exciting because it suggests that if we can decrease or increase expression of genes that are common to both, we could potentially affect both. It's nice to have one treatment."

All of which makes sense, Edelman said. "This gene is involved in the inflammatory process, and asthma is a disease of inflammation and COPD is a disease of inflammation," he noted. "The results are different and the pathways are different but you're still talking about inflammation of the lung. It's not terribly surprising that it appears to be protective in both circumstances."

More information

The American Lung Association has more on lung disease.

Posted: December 2009


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