Four macaque monkeys that received injections of genes for a protein called follistatin into upper leg muscles experienced pronounced and durable increases in muscle size and strength and no adverse effects, the Muscular Dystrophy Association (MDA) announced today. The findings could have implications particularly for injured and aging people worldwide; and for tens of millions experiencing muscle loss associated with cancer, AIDs and muscle diseases.
Longtime MDA grantee Jerry Mendell, a neurologist at Nationwide Children's Hospital in Columbus, Ohio, and Brian Kaspar, a research scientist at that institution who has also received MDA funding, led the study team, which published its findings Nov. 11, 2009, in Science Translational Medicine. Although this treatment strategy will not address the underlying problems in muscle diseases, it may result in a strengthening of remaining muscle.
“Laser sharp is this pioneering gene therapy work with primates,” says R. Rodney Howell, M.D., Chairman of the MDA Board of Directors. “It’s exciting to see profound improvement in muscle size and strength with no adverse effects on any organs or systems including the heart. Improvement in treated thigh muscle is noteworthy because the large muscle is so important when people sit, rise from sitting and for mobility.”
MDA, which has invested more than $10 million funding elegant research involving Dr. Mendell during the past 20 years, has asked Mendell to submit a grant application for a phase one clinical trial as soon as possible.
“This study represents real proof-of-concept that it is possible to improve muscle strength with a gene delivery strategy. The strategy is showing true promise,” adds Sharon Hesterlee, Ph.D., Senior Vice President for MDA Venture Philanthropy.
“Over the years, Jerry Mendell has received more direct funding from MDA than any other investigator,” she explains, “because he keeps finding innovative ways to help the patients he sees every week in the MDA clinic.”
Mendell is co-director of the MDA neuromuscular disease clinic at Nationwide, where he also heads one of five elite centers of excellence in Duchenne muscular dystrophy comprising the MDA DMD Clinical Research Network.
About today's findings
Follistatin is a natural body protein that promotes muscle growth and strength by interfering with the actions of another natural protein, known as myostatin.
Myostatin blocking, a treatment strategy that MDA has been pursuing for several years, is a promising approach to maintain muscle tissue in the face of degenerative disease. Administering genes for the follistatin protein are one of several ways to inhibit myostatin, a strategy that has the potential to help people with all forms of muscular dystrophy and possibly many other types of neuromuscular diseases.
The monkeys used in the study published today did not have a muscle disease, but the researchers say they believe follistatin genes would probably help people who do, because such genes have previously helped mice with a disease resembling Duchenne muscular dystrophy, the most common childhood form of MD.
MDA is the nonprofit health agency dedicated to curing muscular dystrophy, amyotrophic lateral sclerosis (ALS) and related diseases by funding worldwide research. The Association also provides comprehensive health care and support services, advocacy and education.