Myostatin (Growth and Differentiation Factor 8 or GDF-8) gene limits the development of muscle tissue growth or higher concentrated amount cause less developed muscles. In the skeletal muscle cells, myostatin protein is produced. The protein circulates in the blood and travels directly to muscle tissue, upon slowing down the development of muscle stem cells (A type of cell that has the ability to either divide to create more stem cells or produce a cell a type, for unlimited source of adult cells in the bone, muscle or blood). In 1997, geneticists McPherron and Se-Jin Lee discovered and produced a strain of mutant mice that lack the myostatin gene. These mice developed twice the normal strength (“Mighty Mice”). The gene associated with myostatin has been found in the genomes (Differences in the sequence of DNA from one person to the next.) of humans, mice and zebrafish.
In some rare cases, a mutated myostatin gene is inherited in humans and animals In 2004 German boy was diagnosed mutated myostatin gene inherited from each parent, making him considerably stronger than his peers. Reported cases of cattle born having an inactive myostatin gene, referred to as Belgian Blue cattle or “monster cows” (Critics call Belgian Blues). The cattle are hefty, very meaty and lean or double muscle cattle. They are often unable to give birth without caesarian section.
Introducing a substance that can block the gene, researchers hope will lead to developing therapies for muscular dystrophy (Hereditary muscle disease, characterized by progressive skeletal muscle weakness. There are several major forms of muscular dystrophy that affect teens, each which weakens different muscle groups in various ways. Some types are fatal.), and related muscle wasting diseases caused by AIDS, and cancer. Also, inhibiting the gene in livestock to have more muscle mass and less fat content. Unfortunately, substance that can inhibit myostatin gene (Suppress myostatin substances are sold on the Internet, but not approved by the Food and Drug Administration.) may prove to be a major advantage for those athletes, wanting to gain a competitive edge, but like steroids, likely be an illegal banned substance. Besides, long – term side effects have not yet been researched.
Reported in early 2006, New Jersey drug-maker Wyeth (The company’s major divisions include Wyeth Pharmaceuticals, Wyeth Consumer Healthcare and Fort Dodge Animal Health.) will begin first/second clinical human trial study of a drug (MYO-029) that neutralizes or inhibits the myostatin protein (antimyostatin antibody). Study will determine if the drug is effective against muscular dystrophy and sarcopenia (The loss of muscle mass and strength due to aging and diseases.) including cancer. The drug will be administered via intravenous infusion: New infusion every other week for six months and three more months, afterwards. Two muscle biopsies are optional. Pre-clinical studies were conducted on mice, afflicted with muscular dystrophy. These mice were given weekly injections of the antibody into the abdominal cavity. After three months, increased muscle mass and strength in their legs muscles, and less degeneration and fibrosis of their respiratory muscles, when compared to untreated mice. This study contributed to the development of human clinical program. Also, further assessment of the drug, will be tested on dogs, because they are larger and have more severe disease than the mice. According to Dr. Lou Kunkel, one of doctors participating in Wyeth research said: “Just decreasing this protein by 20, 30, 50 percent can have a profound affect on muscle bulk.” Twelve clinical sites will participate in this trial. In the study, a total of 108 patients, and some will be given only a placebo. The effectiveness of MYO-029 will measure the amount found in the blood before and after an infusion. The next stage of the trial is to determine dosing at three different levels and clinical efficacy. Results of the study are expected to be available in late 2006.
