Medical News Observer

Researchers study the use of selective estrogen receptor modulators tamoxifen and raloxifene in patients with muscular dystrophies (MD). Results in an animal study showed significant improvement muscular function. The study findings are published in journal American Journal of Pathology.

Animal study results showing improvement in grip strength, running and changes in muscle histology following use of tamoxifen, and raloxifene. Credit: The American Journal of Pathology.

Selective estrogen receptor modulators have been used for their anti-inflammatory, antifibrosis, prevention of bone loss, and muscle building effects. The investigators found several indicators that tamoxifen and raloxifene delay or even halt disease progression. Within one month,  mice treated with either tamoxifen or raloxifene reduced muscle pathology with a significant reduction in the numbers of degenerating fibers. In one year treated mice show significantly lower histological changes compared to control group which showed high variation in muscle fiber size with focal inflammatory infiltrations.

These histological changes were accompanied by functional improvements in grip force production, extended running time and distance in a treadmill test, and enhancement in cardiac and respiratory functions.

“Our results show that there are two important advantages of tamoxifen and raloxifene treatment over steroids, which have limited benefits for patients with muscular dystrophies. First, the selective estrogen receptor modulators improve both histology and function of all muscles; although steroids improve histology, they improve function to a much lesser extent. Second, selective estrogen receptor modulators enhance bone density, whereas steroids exacerbate osteoporosis and increase the risk for fractures,” explained Qi Long Lu, MD, PhD, director of the McColl-Lockwood Laboratory for Muscular Dystrophy Research, Neuromuscular/ALS Center, Department of Neurology, Atrium Health’s (formerly Carolinas HealthCare System’s) Carolinas Medical Center, Charlotte (NC).

“selective estrogen receptor modulators therapy has great potential to significantly delay or halt muscular dystrophies progression. With the vast amount of safety data available, the selective use of tamoxifen and raloxifene in male and female patients with muscular dystrophies is an attractive and realistic alternative to steroids,” noted Dr. Lu.

Reference: Wu, Bo, Sapana N. Shah, Peijuan Lu, Lauren E. Bollinger, Anthony Blaeser, Susan Sparks, Amy D. Harper, and Qi L. Lu. “Long-Term Treatment of Tamoxifen and Raloxifene Alleviates Dystrophic Phenotype and Enhances Muscle Functions of FKRP Dystroglycanopathy.” The American Journal of Pathology 188, no. 4 (2018): 1069-080. doi:10.1016/j.ajpath.2017.12.011.

Research funding: Carolinas Muscular Dystrophy Research Endowment at the Carolinas HealthCare Foundation.

Adapted from press release by Elsevier.