When mice lack one protein, myostatin, and have overproduction of a second protein, follistatin, new research shows that the animals can increase their muscle fiber size by 117 percent. The discovery could be useful for treating patients with muscular dystrophy.
Se-Jin Lee, a doctor and professor of molecular biology and genetics at Johns Hopkins University, discovered previously that the absence of myostatin leads to oversized muscles in mice and humans. One drug currently being tested in a clinical trial blocks the production of myostatin.
But follistatin is a different protein that lies on the same pathway, and Lee recently found that follistatin makes muscles grow even larger than the absence of myostatin alone. Not only does follistatin block the production of myostatin, it also results in additional muscle growth itself, Lee discovered.
When Lee added follistatin to mice that also lacked myostatin, the mice averaged a 117 percent increase in muscle fiber size and a 73 percent increase in total muscle fibers compared to normal mice.
Lee explained that the discovery suggests there might be other components that work with myostatin on the same pathway, and might also yield a greater capacity for increasing muscle growth.
Lisa Zyga via: Johns Hopkins University
Lee's Web page