Two major clinical trials are testing for the first time whether treating inflammation can reduce the risk of a heart attack or stroke, potentially opening up a new line of attack in the battle against cardiovascular disease.
Until now, strategies to fight these killers have focused largely on well-known risk factors such as high blood pressure and cholesterol. The new studies, one sponsored by the National Institutes of Health and the other by pharmaceutical giant Novartis SA, will test the hypothesis that inflammation plays a crucial role in the underlying biology that makes heart disease and stroke the No. 1 and No. 4 causes of death in the U.S., respectively.
Inflammation is part of the body's normal healing response to injury. When the walls of the coronary arteries or the vessels that carry blood to the brain suffer injury from the effects of smoking, obesity and abnormal cholesterol, for instance, the immune system as part of the inflammatory response dispatches cells to repair the damage, researchers say.
But in the face of a constant assault by such irritants over decades, possibly abetted by genetics, that system can go into overdrive. Instead of protecting the vessels, inflammation becomes chronic, leading to the accumulation and potential rupture of arterial deposits called plaque that can cause heart attacks and strokes.
Research over two decades has shown that people with chronic inflammation—detectable at low levels, for instance, with a high-sensitivity test for a marker called C-reactive protein—are at significantly higher risk of heart attack and stroke compared with those with evidence of little or no such inflammation.
But whether the risk can be mitigated by inhibiting or shutting down the process with anti-inflammatory drugs isn't known.
"This goes beyond simply asking, is inflammation a marker of risk (for cardiovascular disease) to asking if it's a target for therapy," said Paul M. Ridker, director of the center for cardiovascular-disease prevention at Harvard-affiliated Brigham and Women's Hospital in Boston, who is leading both trials.