Heart-disease drugs called statins have been designed to reduce the body's production of cholesterol, but they also help heart patients by reducing inflammation - an advantage surprise that delighted but puzzled researchers. Now a team has identified where in the immune system statins block inflammation system. Finally, statins could be used to prevent rejection of transplanted or alleviate the symptoms of autoimmune diseases organs.
Statins have a wide range of effects. Earlier this year, researchers have suggested that these drugs reduce the risk of Alzheimer's disease ( ScienceNOW , 13 November) and build bone mass ( ScienceNOW , 27 June). One of the first indications that drugs can also calm the immune system came from a study of heart transplant patients 1995. Patients who took statins showed less signs of rejection of the transplanted organ.
To study, cardiologist Francois Mach of Geneva Medical School in Switzerland and colleagues focused on inflammation in blood vessels. When the immune system triggers this inflammation, it can lead to transplant rejection - and can aggravate heart disease. Researchers followed the effects of statins on the cells of the inner lining of blood vessels when they are combined with several types of immune cells. They found that statins block a chemical messenger that activates a kind of white blood cell called a T cell. This slows down the cascade of cellular interactions that normally causes the kind of inflammation that leads to transplant rejection, they report in the December issue of Nature Medicine .
Mach stresses that his research could have applications for autoimmune diseases as well, some of which involve T lymphocytes whack. His team plans to test whether statins can prevent a disease of arthritis such as rheumatoid arthritis in mice.
The conclusion that statins activate T cells block is "a huge confirmation [that statins] have cholesterol-independent properties by which they can save lives," says Jon Kobashigawa cardiologist at the University of California , Los Angeles, who led the 1995 heart transplant study. But Wulf Palinski, a specialist of atherosclerosis at the University of California, San Diego, warns that what works in cell culture may not work in a living animal. "The immune system is extremely complicated," he said.
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