U.S. researchers say they're closer to finding out how to dampen the inflammatory response associated with atherosclerosis, or hardening of the arteries, a condition that can lead to heart attacks and strokes.

Scientists from Harvard Medical School in Boston studying mice found the absence of a single protein called ROCK1 reduced inflammation provoked by fatty deposits in the walls of blood vessels.

In their study, the scientists found that ROCK1 was necessary for immune cells known as macrophages to "clean up" vascular walls when they came into contact with fatty deposits.

Inflammation is a normal byproduct of the cleanup process, but if the injury is not resolved, more macrophages are drawn to the area, and at times, the immune system doesn't know when to cool down.

When ROCK1 is absent, macrophages don't contribute to these fatty deposits and mice in the study showed significantly less inflammation and atherosclerosis.

The researchers say this discovery could lead to new treatments, such as ROCK1 inhibitors, that could dampen the inflammatory response to fatty deposits and slow the progression of atherosclerosis, and in so doing, reduce the incidence of heart attacks and strokes.

Second study looks at resolving inflammation once started

Their finding was published in the June issue of the Journal of the Federation of American Societies for Experimental Biology, along with a similar study from Baylor College of Medicine in Houston, Tex.

The Harvard researchers looked at preventing atherosclerosis before the immune system kicks into gear and the second group studied ways to prevent it after the immune system has been activated.

The Baylor College of Medicine study says some natural lipid mediators, which prevent inflammation from running amok, are derived from omega-3 polyunsaturated fatty acids found in certain fish.

Lead author Dr. Aksam Merched said the body can sometimes resolve the inflammation, but often the response goes into overdrive. He says the mediators tell the immune system not to overreact.

"Continued inflammation draws more macrophages to the site of the inflammation. They produce molecules that turn this into a vicious cycle," Merched said.

"Aspirin can produce one family of these mediators and can be used daily, but people should consult their doctors to see if it’s right for them," he says.