A research team has published additional evidence that the immunosuppressive drug cyclosporin may prevent cardiac hypertrophy, a potentially dangerous enlargement of the heart. Dr. Jeffery D. Molkentin, of Children's Hospital Medical Center, Cincinnati, Ohio, found that cyclosporin and a similar drug, known as FK506, prevented cardiac hypertrophy in mice that were genetically or experimentally predisposed to develop that condition. Their report appears in the September 11th issue of the journal Science. As Reuters Health reported in April, Molkentin's group previously discovered that cyclosporin and FK506 inhibit the activity of calcineurin, an enzyme found in heart muscle cells that has a role in causing cardiac hypertrophy.
Cardiac hypertrophy is a response of the heart to damage.
Under stress such as that caused by a heart attack, high blood pressure, or hormone disorders, the heart tries to compensate by increasing its size to boost cardiac output. Although the enlargement is initially beneficial, the heart can eventually become too large, increasing the risk of life-threatening heart failure. Patients receiving long-term cyclosporin therapy can develop a number of serious side effects, Molkentin's team points out. The researchers suggest that if calcineurin inhibitors prove to be useful in treating cardiac hypertrophy in humans, it may be necessary to create new drugs. In an interview with Reuters Health, Molkentin noted that one of the side effects of long-term cyclosporin therapy is high blood pressure.