Apart from fighting heart disease, the cholesterol-lowering drugs known as statins may also prevent and treat relapses of multiple sclerosis (MS). This debilitating disease, which causes loss of motor control and paralysis, affects as many as 2.5 million people worldwide.
MS is an autoimmune disease in which the body's immune cells, specifically helper T cells, attack myelin, the fatty tissue that covers and protects the nerves of the CNS. When myelin and the underlying nerves are destroyed, nerve impulses cannot be transmitted, causing the disabling symptoms of MS. At present, individuals have to take painful injections to relieve these symptoms. Now, a group led by Scott S. Zamvil of the University of California, San Francisco, report that the popular cholesterol-lowering drug atorvastatin (Lipitor), which can be taken in pill form, lessened or entirely suppressed the paralysis seen in a mouse model of MS (Nature, 7 November 2002).
Mice with experimental autoimmune encephalomyelitis (EAE) were fed atorvastatin once a day for several weeks. Zamvil's team saw that, in addition to abrogating symptoms, the drug reduced the amount of brain inflammation and CNS damage. They determined that atorvastatin inhibited the activation of T cells and the production of pro-inflammatory cytokines, leading to suppression of EAE. This is not the first use of statins in immunosuppression; they have also been useful in reducing rejection in heart transplant patients.
Although the results of the mouse study are promising, the authors still plan clinical trials to investigate the effects of atrovastatin in humans with MS. The drug may also prove effective in the treatment of other autoimmune diseases, such as diabetes and rheumatoid arthritis.