Researchers at the University of California, Berkeley, have for the first time determined the mechanism by which muscle cells are destroyed in Duchenne muscular dystrophy, a discovery that could lead to the development of new forms of drug therapy for the disorder. UC Berkeley biologist Richard Steinhardt and his colleagues report in today's Science magazine that the destruction in both mouse and human cells is caused by a defect in cellular membranes that allows high levels of calcium atoms to enter muscle cells and causes them to degenerate.
In light of this finding, other researchers are already planning clinical trials of drugs that might block entry of calcium into muscle cells in hopes that the drugs will prevent muscle degeneration.
A family of drugs called calcium blockers is already used to treat heart disease and high blood pressure, and researchers hope that one of these or a similar drug might prove to be an effective therapy for muscular dystrophy.
The new findings complement the recent discovery of the defective gene for Duchenne muscular dystrophy and provide insight into how the defective protein produced by the gene may damage muscle cells.
Researchers have been attempting to replace the defective gene in the muscle cells of muscular dystrophy victims by using a technique called myoblast transfer therapy, and the new finding may provide an "exciting" alternate way to attack the devastating disease, according to Lawrence Stern, president of the Muscular Dystrophy Association.
Babies with muscular dystrophy appear normal at birth, but develop a progressive weakening of the muscles, so that by the age of 11 they are usually in a wheelchair. There is no effective therapy for the disease, and most victims die in their late teen-age years or early 20s when the muscles that operate the heart and lungs cease functioning.
Researchers found the gene that causes Duchenne muscular dystrophy three years ago.