Smoking Damages Key Enzyme in the Lungs

Smoking appears to disrupt an important enzyme in the lungs, possibly explaining some of the habit's damaging health effects, researchers report.

The study focused on the effect of smoking on monoamine oxidase A, or MAO A, an enzyme that breaks down many compounds that affect blood pressure.

Using a radiotracer to track the enzyme, researchers found that smokers had MAO A levels that were 50 percent lower than nonsmokers, said lead researcher Joanna S. Fowler, program director of the Brookhaven Center for Translational Neuroimaging in Upton, N.Y.

MAO A breaks down many compounds affecting blood pressure, and the lung is a major organ focused on degrading some of these compounds, Fowler said. So lower levels of the enzyme in smokers' lungs could contribute to high blood pressure or pulmonary disease, the study said.

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