Researchers discover new way to block inflammation

(Press-News.org) Researchers at NYU Langone Medical Center have discovered a mechanism that triggers chronic inflammation in Alzheimer's, atherosclerosis and type-2 diabetes. The results, published today in Nature Immunology, suggest a common biochemical thread to multiple diseases and point the way to a new class of therapies that could treat chronic inflammation in these non-infectious diseases without crippling the immune system. Alzheimer's, atherosclerosis and type-2 diabetes—diseases associated with aging and inflammation—affect more than 100 million Americans.

When the body encounters a pathogen, it unleashes a rush of chemicals known as cytokines that draws immune cells to the site of infection and causes inflammation. Particulate matter in the body, such as the cholesterol crystals associated with vascular disease and the amyloid plaques that form in the brain in Alzheimer's disease, can also cause inflammation but the exact mechanism of action remains unclear. Researchers previously thought that these crystals and plaques accumulate outside of cells, and that macrophages—immune cells that scavenge debris in the body—induce inflammation as they attempt to clear them.

"We've discovered that the mechanism causing chronic inflammation in these diseases is actually very different," says Kathryn J. Moore, PhD, senior author of the study and associate professor of medicine and cell biology, Leon H. Charney Division of Cardiology at NYU Langone Medical Center.

The researchers found that particulate matter does not linger on the outside of cells. Instead, a receptor called CD36 present on macrophages draws the soluble forms of these particles inside the cell where they are transformed into substances that trigger an inflammatory response. Says Dr. Moore, "What we found is that CD36 binds soluble cholesterol and protein matter associated with these diseases, pulls them inside the cell, and then transforms them. The resulting insoluble crystals and amyloid damage the macrophage and trigger a powerful cytokine, called interleukin-1B, linked to a chronic inflammatory response."

These findings hold exciting clinical implications. When the researchers blocked the CD36 receptor in mice with atherosclerosis (in which cholesterol thickens the arteries), the cytokine response declined, fewer cholesterol crystals formed in plaques, and inflammation decreased. Consequently, atherosclerosis also abated.

Other less-targeted strategies to control inflammation may hamper the immune response, but the CD36 strategy spares certain cytokines to fight off pathogens, while blocking CD36's ability to trigger interleukin-1B.

"Our findings identify CD36 as a central regulator of the immune response in these conditions and suggest that blocking CD36 might be a common therapeutic option for all three diseases," says Dr. Moore.

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Support for this work comes from The National Institutes of Health and the American Heart Association.

About NYU Langone Medical Center

NYU Langone Medical Center, a world-class, patient-centered, integrated, academic medical center, is one of the nation's premier centers for excellence in clinical care, biomedical research and medical education. Located in the heart of Manhattan, NYU Langone is composed of three hospitals – Tisch Hospital, its flagship acute care facility; the Rusk Institute of Rehabilitation Medicine, the world's first university-affiliated facility devoted entirely to rehabilitation medicine; and the Hospital for Joint Diseases, one of only five hospitals in the nation dedicated to orthopaedics and rheumatology – plus the NYU School of Medicine, which since 1841 has trained thousands of physicians and scientists who have helped to shape the course of medical history. The medical center's tri-fold mission to serve, teach and discover is achieved 365 days a year through the seamless integration of a culture devoted to excellence in patient care, education and research. For more information, go to http://www.NYULMC.org.