Originally published in The Havok Journal on 14 July 2014.
In 1997 Dr. Se-Jin Lee and Alexandra McPherron from Johns Hopkins University School of Medicine discovered a gene encoding a substance known as myostatin. These two geneticists were able to successfully breed mice who possessed so-called “loss of function mutations” in the gene responsible for the production of myostatin. This basically means that the mice had mutations that inhibited the production of myostatin (aka myostatin “knockout” mice). The mice also earned the name “mighty mice” because the result of the mutation was increased muscle mass compared to normal mice. Later studies discovered the existence of myostatin knockout bulls known as Belgian Blue Bulls, and myostatin knockout whippet dogs.
Over the years, a great deal of research has been done on the effects of myostatin within the human body. To simplify an incredibly complex process, myostatin, also known as growth differentiation factor (GDF-8), has an inhibitory effect on muscle growth. It is what is known as an autocrine/paracrine hormone (a hormone that acts on the same cell that released it as well as those cells directly adjacent to it) that is released by muscle cells. Its basic function is to keep muscle cells from getting too large or hypertrophy.
In a healthy adult, it plays an integral part in muscle homeostasis by antagonizing the effects of substances that would cause muscle growth, and helping to balance the cell differentiation and overall skeletal muscle growth. Not too big, not too small, but just right, for a particular person. Everyone naturally has a certain amount of muscle tissue that maximizes his or her potential.
Now we know what myostatin does and how to inhibit it. This ability to inhibit myostatin has provided very encouraging possibilities for treatment of muscle wasting that occurs with cancer and muscle wasting disorders. It has also been a proposed therapy for anyone who suffers from an injury that requires him or her to be non-weight bearing for an extended period of time such as a torn ACL. The inhibition of myostatin in these cases would prevent muscle loss due to disuse in the lower limb on the side of the injury, which would allow a much quicker return to normal activity.
Yet another proposed use for myostatin inhibitors is for morbid obesity. Researchers have found that myostatin secretion is increased in the morbidly obese. This poses a problem for these people because they will have a much harder time losing the excess body fat if they can’t put on lean muscle. Healthy and lean people have increased metabolic rates as compared to individuals who are obese, due in part to the fact that healthy individuals possess an increased amount of lean muscle mass. Unhealthy and overweight people however, generally have less lean muscle mass and therefore have decreased metabolic rates.
The more muscle mass an individual possesses, the more energy their body must use to maintain that muscle. In other words, these individuals burn more calories even when they’re not physically active. However, when someone is overweight it creates a vicious cycle. The fact that myostatin is diminished in obese patients means that they will have a much harder time putting on muscle and increasing their metabolic rate to burn the necessary calories to subsequently lose excess body fat. If myostatin release could be inhibited, these individuals would be able to put on more muscle (provided that they’re on a proper diet and exercise plan), thereby stopping the cycle and facilitating better results. It should be noted that there is no such thing as a miracle weight loss pill, and that diet and exercise is still the best therapy. Myostatin inhibitors for obesity should only be used as an adjunct therapy to regular diet and exercise.
Although there are a great many medical benefits in the development of myostatin inhibitors, unfortunately, there are those who abuse any drug that can increase their performance who would be very interested in abusing myostatin inhibitors. One can certainly see that the ability to pack on a normally impossible amount of muscle in a very short period of time would be a very alluring option for athletes and amateurs (by far most performance enhancing drug use is by the idiot gym rat, only a small percentage of pros use them).
It can be assumed with a great deal of certainty that if myostatin inhibitors became widely available, they would be used by the gym rat and other amateurs to gain a competitive edge and thus provide another avenue in the already large city of performance enhancing drugs. Myostatin inhibitors would be even more highly desirable performance enhancers given the fact that they are practically undetectable if you’re not actively using them. This means that in order to prove that someone was using them, you’d pretty much have to catch them in the act.
Despite the potential for abuse in the world of sports and amateur weightlifting, the potential benefits to myostatin inhibitors far outweigh the costs. Yes, sports associations would have one more thing to worry about, but we could help diminish the terrible side effect of muscle wasting that is inherent in so many chronic diseases such as Duchenne and Becker Muscular Dystrophy, help people who are required to be non-weight bearing onto a faster road to recovery, and perhaps provide another adjunct therapy to diet and exercise in the fight against obesity in this country.
5. ROSS, M. H., & PAWLINA, W. Histology: a text and atlas : with correlated cell and molecular biology. Baltimore, MD, Lippincott Wiliams & Wilkins; 2006: 325-326.