The bull you see in the photo does not need to spend whole days in the gym or follow special diets to keep fit. His extraordinary muscle development is simply due to a mutation in the gene that codes for myostatin.
What is Myostatin?
Myostatin is a protein discovered in 1997 by scientists McPherron and Se-Jin Lee during studies on cell differentiation and proliferation. To understand what its real function was, mice were made to mate in which the gene that codes for myostatin had been inhibited.
The homozygous offspring, carrying both mutated genes, had superior muscle development compared to heterozygous mice (carrying only one mutated gene) and normal mice. The body size was 30% larger, the muscle was hypertrophic and the weight was 2 or 3 times greater than in natural guinea pigs. Subsequently the histological analysis showed an increase both in the size of the single muscle cells (hypertrophy) and in their number (hyperplasia).
By studying two particular breeds of cattle obtained by crossing particularly muscular heads, the researchers discovered the presence of a mutation in the gene that codes for myostatin. A "further confirmation of its function came from the study on the expression of the gene in other animal species such as cat, chicken and pig; the hypothesis that myostatin interacts with muscle development, inhibiting it, was confirmed.
Role of myostatin in muscle development
Today, 10 years after its discovery, it is known that myostatin is mainly produced by skeletal muscle cells (some studies have also revealed its presence in adipose, heart and bone tissue). Its action is regulated by the presence of an inhibitor called follistatin. The higher the level of follistatin, the greater the muscle development. It appears that folistatin is able to interact with satellite cells by stimulating the proliferation of new muscle cells (hyperplasia). Normally the increase in muscle mass is due only to the increase in cell size (hypertrophy), while a slight hyperplasia could occur only in special cases (muscle injuries).
From a chemical point of view, myostatin is a protein composed of two subunits formed by a sequence of 110 amino acids and is part of the larger group of growth and differentiation factors beta (TGF-B).
His discovery has opened new horizons in the treatment of muscular and heart diseases, in sports and in cattle breeding. We think, for example, of the possible muscle regeneration following an injury, or the regeneration of the myocardium following a heart attack.
The application of myostatin inhibitors in the treatment of muscular dystrophy has recently aroused particular interest, although some studies have dampened the initial optimism.
Current research is focusing on the study and development of these potentials but there are still many hypotheses and few certainties. Studies on the role of myostatin in the human organism are few, often discordant, and still awaiting confirmation.
In 2004, studying a 5-year-old German boy who presented abnormal development of strength and muscle mass, scientists discovered for the first time in humans the presence of a mutation in the genes that code for myostatin. The influence on phenotypic expression was identical to that observed in laboratory mice and in the breeds of cattle studied so that the muscle strength of the child was similar or even greater than that of an adult. Very interesting is that the mother of the child, from whom he inherited one of the two mutated alleles, she was a professional sprinter and some of her ancestors are remembered for their extraordinary strength
From subsequent analyzes it emerged that the absence of myostatin was the only cause of excessive muscle development. All the other anabolic factors such as testosterone, GH and IGF-1, also considering the young age of the subject, were perfectly normal. .
It can therefore be hypothesized that the absence of myostatin stimulates muscle hypertrophy and hyperplasia regardless of the presence of anabolic hormones. This hypothesis, still awaiting confirmation, seems somewhat optimistic. Muscle growth is in fact the result of a subtle balance between anabolic and catabolic factors and a single hormone, a gene or a particular substance is not enough to influence it significantly. To confirm this, there are studies in the literature that show that there are no important differences in the amount of muscle mass between normal subjects and others with myostatin deficiency.
What is certain is that in 2005 a large American pharmaceutical company, Wyeth, applied for a patent for the discovery of an antibody capable of neutralizing myostatin.
In recent years, some supplement companies have introduced products to the market that promise to naturally inhibit myostatin production. Beyond the cost, the effectiveness of the products in question is very low and most likely nothing. Moreover, studies carried out on professional bodybuilders have found completely normal values of myostatin in the muscles.
In any case, until the side effects and benefits deriving from the inhibition of myostatin have been determined precisely, prudence is a must. So if you are thinking that the lack of results is due to an overexpression of myostatin, try to change your mind and train with constancy and determination, the results will come anyway!
