Tamoxifen ameliorates symptoms of Duchenne muscular dystrophy in mouse model

A new study has found that tamoxifen, a well-known, off patent, breast cancer drug, can counteract some pathologic features in a mouse model of Duchenne muscular dystrophy (DMD). At present, no treatment is known to produce long-term improvement of the symptoms in boys with DMD, a debilitating muscular disorder that is characterized by progressive muscle wasting, respiratory and cardiac impairments, paralysis, and premature death. This study will be published in the February 2013 issue of The American Journal of Pathology.

Using the mdx5Cv mouse model of DMD, investigators found that tamoxifen, given orally for more than a year, "caused remarkable improvements of muscle force and of diaphragm and cardiac structure," according to lead author Olivier Dorchies, of the Department of Pharmacology, Geneva-Lausanne School of Pharmaceutical Sciences of the University of Geneva and University of Lausanne, Switzerland. For instance, in the heart, fibrosis was diminished by around 50%. In the diaphragm, the muscle of the dystrophic mouse thought to be most like that of human DMD, tamoxifen reduced fibrosis while increasing thickness as well as the number and average diameter of muscle fibers. The net effect was that tamoxifen raised the amount of contractile tissue available for respiration by 72%.

Improved leg muscle structure