Any serious athlete knows that good results take time. Dedication to training, proper nutrition, and adequate rest contribute collectively to any successful outcome. Some athletes choose to add a variety of natural supplements to their training regimen; yet even with this boost, no single “magic bullet” exists. Could myostatin fill this void?
Myostatin and Double Muscling
Myostatin-related muscle hypertrophy, a rare condition characterized by reduced body fat and increased muscle size/strength, comes about as a result of genetic changes in the MSTN gene.
Several years ago, researchers began experimenting with a naturally-occurring substance in the body known as myostatin. A muscle-specific member of the transforming growth factor- (TGF- ) superfamily, myostatin plays an essential role in the negative regulation of muscle growth. In research labs, purposeful genetic deletion of myostatin results in excessive growth of skeletal muscle. In 1997, a team of scientists led by McPherron and Lee at Johns Hopkins University was investigating a group of proteins that regulate cell growth and differentiation. During their investigations, they discovered the gene possibly responsible for the phenomenon of increased muscle mass, also called “double-muscling“. By knocking out the gene for myostatin, the specific protein for which the gene encodes in mice, these scientists demonstrated that the transgenic mice developed 2-3x more muscle than mice exhibiting the same gene intact. Lee commented that the myostatin gene knockout mice “look like Schwarzenegger mice.“
More Than Mice
As it turns out, this phenomenon does not end with the murine model. Experimentation of genes present in skeletal muscle of cattle led to the discovery of two breeds of double-muscled cattle, Belgian Blue and Piedmontese, both of which manifested mutations in the gene that codes for myostatin. The double-muscling trait discovered in both the mice and the cattle seems to indicate that myostatin performs the same biological function in these two species.
Ameliorating Disease or Improving Athleticism?
Armed with this knowledge, one begs the question of whether this adaptation could work in humans. Many authors of the myostatin studies have speculated that such manipulation in humans may reverse muscle wasting commonly associated with muscular dystrophy, AIDS and end-stage cancer, and studies already exist to explore such potential. The notion of an antibody vaccine for the myostatin protein no longer seems a faraway reality, considering the incredible benefits such a breakthrough would have on patients suffering from the aforementioned diseases.
But medical research, undertaken in the hopes of improving the quality of life for individuals with cachexic conditions, varies greatly from manipulation for athletic prowess. Some supplement companies offer products that claim to significantly reduce the amount of serum myostatin circulating in the body, thereby enabling greater growth of lean muscle mass. Serious bodybuilders, looking for any edge in today’s highly competitive field, buy into this, despite necessary further research needed in order to ascertain the long-term effects to other bodily systems. Factual claims or not, the question remains: at what point might an athlete cross over from “supplementation“ to “inappropriate genetic manipulation“? While competitive athletes entertain the possibility of a simple way to eradicate what might be the biggest obstacle in one’s ability to gain muscle, at what cost/health risk should an athlete engage in such activity?
Fortunately, at least for now, a good deal of hesitancy exists among the masses in terms of jumping on any anti-myostatin bandwagon for the sake of enhancing one’s ability to add lean muscle tissue. More prudent athletes seem to take the issue under careful consideration, exploring the research at hand. Certainly the shall always see supplements available for sports performance enhancement, whether natural or steroid-based, as well as competitors willing to exploit scientific research for personal gain.
Aerobic Exercise and Insulin Resistance
Medical experimentation within the myostatin realm appears scarce at best. However, scientists recently hypothesized that increased expression of myostatin may play a key role in signaling pathways associated with obesity and insulin resistance.
Researchers demonstrated that myostatin protein levels decreased in muscle /plasma samples following aerobic exercise. Furthermore, the strong correlation between plasma myostatin levels and insulin sensitivity suggested a cause-effect relationship, subsequently confirmed by additional studies.
Since both muscle and plasma myostatin protein levels revealed some regulation by aerobic exercise, perhaps myostatin plays a definitive role in the pathway of acquired insulin resistance seen in individuals with sedentary lifestyles. If moderate exercise proves sufficient in both reducing circulating myostatin levels and improving insulin sensitivity, physicians may want to consider instructing diabetic patients on the therapeutic benefit of exercise. In conjunction with exercise professionals, physicians may even help patients determine a target for ideal mode, dose and intensity of exercise for health benefits.
1.Johns Hopkins Magazine, June 1997
2.McPherron, AC, AM Lawler, SJ Lee. Regulation of skeletal muscle mass in mice by a new TGF-b superfamily member. Nature 1997, 387:83.
3.McPherron, AC, SJ Lee. Double muscling in cattle due to mutations in the myostatin gene. Proc Natl Acad Sci USA 1997, 94:12457
4. Kunihiro Tsuchida The role of myostatin and bone morphogenetic proteins in muscular disorders. Sumary, Expert Opinion on Biological Therapy, February 2006, Vol. 6, No. 2, Pages 147-154.
5. Wagner, KR. Muscle regeneration through myostatin inhibition. Curr Opin Rheumatol., 2005 Nov; 17(6):720=4
6. James F. Tobin and Anthony J. Celeste. Myostatin, a negative regulator of muscle mass: implications for muscle degenerative diseases. Current Opinion in Pharmacology, Volume 5, Issue 3, June 2005, Pages 328-332
About the Author
Cathleen Kronemer is an AFAA-Certified Group Exercise Instructor, NSCA-Certified Personal Trainer, competitive bodybuilder and freelance writer. She is employed at the Jewish Community Center in St. Louis, MO. Cathleen has been involved in the fitness industry for 35 years.
She welcomes your feedback and comments!