Cigarette Smoke’s New Way To Infiltrate Lungs

(Ivanhoe Newswire) – Cigarette smoke shuts off a key enzyme in airways that regulates the body’s response to inflammation, according to findings from the University of Alabama at Birmingham.

The UAB researchers say smoke inhibits the enzyme, called Leukotriene A4 Hydrolase (LTA4H), causing it to fail in its job of shutting down white blood cells following a successful response to inflammation.

The team says the research study identified a previously unknown substrate of LTA4H called proline-glycine-proline (PGP). In a normal response to inflammation, PGP’s role is to recruit neutrophils ““ white blood cells ““ that rush to the scene and attack the cause of the inflammation.

When the job is over, LTA4H steps in to shut off PGP, in turn halting the recruitment of neutrophils and ending the body’s defensive stand.

"We found, however, that cigarette smoke inhibited LTA4H, preventing it from shutting down PGP," J. Edwin Blalock, Ph.D., was quoted as saying.

"Drugs are in design that would reduce LTB4 by shutting down LTA4H," he said. "But we now know that LTA4H has a beneficial role to play in the reduction of PGP.

Source : Science; September 2, 2010