Navigation Links
Drugs to bulk up muscles may make injuries more likely
Date:1/22/2008

ANN ARBOR, Mich. Block the action of a protein that normally regulates muscle mass, and watch your muscles grow.

That may sound like a good idea to people with muscle-wasting diseases such as muscular dystrophy, and to older people, whose muscles naturally get smaller and weaker with age. Drugs that restrict the protein myostatin, which normally prevents muscles from being overly bulky, are currently under study, but not on the market, for some medical conditions.

Such drugs, called myostatin inhibitors, also are stirring interest among body builders and athletes. There are already signs of a nascent black market for what might become another illegal performance-enhancing drug in organized sports.

Now, a new University of Michigan study in mice suggests that while myostatin inhibitors may indeed bulk up muscles, they may also bring a troubling side effect small, brittle tendons that could make muscle injuries more likely.

Those interested in myostatin inhibitors need to be aware of the fact that by doing these things to muscles, they may be having negative effects on tendons, says John A. Faulkner, Ph.D., the studys senior author and professor in the Department of Molecular and Integrative Physiology at the U-M Medical School. He is also a research professor at the U-M Institute of Gerontology and professor of biomedical engineering at the U-M College of Engineering. The study results appear in the Jan. 8 print issue of the Proceedings of the National Academy of Sciences.

When you lift weights at the gym, muscle tissue gets damaged. That sets off the release of myostatin, starting a process that clears away damaged proteins and sets the stage for muscle rebuilding, says the studys first author, Christopher L. Mendias, Ph.D. The study suggests we need normal myostatin action for other reasons, too.

It also appears to make tendons bigger and more flexible, says Mendias, a U-M post-doctoral research fellow in the Regenerative Sciences Training Program in the Department of Surgery at the U-M Medical School.

It is known that blocking myostatins activity increases muscle mass and strength, but also makes muscle fibers more vulnerable to injury. The U-M team broke new ground by asking if myostatin also affected the make-up and performance of tendons, the fibrous, tough tissues that connect muscle to bone.

Tendons are stiffer than muscles to begin with, and get stiffer with age. If tendons are brittle and short, as they were in myostatin-lacking mice in the study, they cant adequately do their important job of buffering against muscle injuries.

The tendon acts like a spring, Faulkner says, to reduce some of the force on the muscle in a lengthening contraction. Contraction-induced injury is the most common way we injure our muscles. This type of injury already occurs frequently in people with muscular dystrophy so short, brittle tendons could aggravate the problem if myostatin inhibitors turn out to cause the effect in people.

The research team conducted a series of studies using a strain of laboratory mice that lacked the ability to produce myostatin. They tested the mechanical properties of tendons, compared to tendons in a strain of normal laboratory mice. They isolated and treated tendon cells with myostatin and examined what genes control tendon activity. They were able to identify tendon genes that respond to myostatin, which is produced in muscles, showing that myostatin acts as a hormone to promote strong, flexible tendons.

The findings in mice that lack myostatin are very preliminary and will need to be tested in other mouse strains before seeing if they hold true in people, the researchers say. Its also necessary to explore whether tendon brittleness is a problem if myostatin is merely reduced.

In the meantime, the results are intriguing and cautionary for the variety of people interested in the potential of myostatin inhibitors to increase muscle mass.

For people with the most common forms of muscular dystrophy as well as muscle-wasting diseases, myostatin inhibitors represent one potentially effective type of treatment that is being explored. These inhibitors may be able to reverse the loss of muscle mass and also lessen fibrosis, a build-up of connective tissue in muscle that afflicts people with muscular dystrophy and can be a problem in aging and inactivity. One myostatin inhibitor is currently being tested in people as a possible treatment for Duchenne muscular dystrophy, a debilitating disease that affects one in 3,500 boys worldwide.

For certain types of competitive athletes, the possibility that tendons become stiffer with myostatin inhibitors may not seem a disadvantage, says Mendias, who is also an athletic trainer. The prospect of widespread interest in myostatin inhibitors for enhancing performance, which like steroid use is illegal, is very real, he says, adding that the study results point to a greater need for a system to detect their use.


'/>"/>

Contact: Anne Rueter
arueter@umich.edu
734-764-2220
University of Michigan Health System
Source:Eurekalert  

Related medicine news :

1. A new view of drugs used to treat rheumatoid arthritis
2. Bone-Strengthening Drugs May Be Overprescribed
3. Using Product Marketing to Launch Drugs That Outperform the Competition
4. China Nepstar Chain Drugstore Launches Charitable Initiative to Promote Awareness of Low-income Working Womens Health Issues
5. Weight gain induced by antipsychotic drugs can be avoided
6. Popular osteoporosis drugs triple risk of bone necrosis
7. Antiretroviral Drugs May Prevent Vaginal Transmission of HIV
8. Aggression as rewarding as sex, food and drugs
9. Lowering Co-Pays on Some Drugs Help Fight Chronic Diseases
10. Americans pay the most for prescription drugs and still dont take them
11. FDA Reports New Risks Posed by Anemia Drugs
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Drugs to bulk up muscles may make injuries more likely
(Date:6/26/2017)... ... June 26, 2017 , ... New patients with missing teeth ... with or without a referral. Dr. Cotey is a trusted dentist who has placed ... replacement option. , Patients with missing teeth in Fitchburg, WI, are encouraged to find ...
(Date:6/25/2017)... ... ... CareSet Labs released the Root NPI Graph today at the 2017 ... version of the Doctor Referral teaming dataset commonly available from Medicare. , Originally created ... the “Doctor Referral Dataset” as released by Medicare and “DocGraph” as released by Trotter, ...
(Date:6/24/2017)... ... 24, 2017 , ... Dr. Mitchell Mehlman and his staff ... Ronkonkoma, Dental365 offers patients high-quality and affordable routine and emergency dental care. Dental365 ... into their patients’ busy lifestyles. Dental365 also gladly work with most insurance plans. ...
(Date:6/23/2017)... , ... June 23, 2017 , ... By scoring 100% ... ninth consecutive four-star rating from premier online charity evaluator, Charity Navigator, validating ANRF's work ... 1% of all charities reviewed by Charity Navigator and earns ANRF a spot on ...
(Date:6/23/2017)... ... June 23, 2017 , ... Military Connection ... denied entry to the JFK Virgin Atlantic lounge. , Bensko is no stranger ... six years ago, Bensko dedicated her life to supporting our wounded veterans. A world-class ...
Breaking Medicine News(10 mins):
(Date:6/9/2017)... , June 9, 2017 AirXpanders, Inc. (ASX: ... on the design, manufacture, sale and distribution of the ... the progress of its commercial roll-out in ... in more than one hundred (100) medical institutions and ... AeroForm offers a needle-free alternative for women who choose ...
(Date:6/7/2017)... DUBLIN , June 7, 2017 Endo ... on June 7, 2017, the Hon. Joseph R. ... District of West Virginia , entered ... Systems, Inc. Pelvic Repair System Products Liability Litigation (the ... filed MDL cases to provide expert disclosures on specific ...
(Date:6/3/2017)... 2017  Eli Lilly and Company (NYSE: ... the Phase 3 MONARCH 2 study showed that ... in combination with fulvestrant, significantly improved progression-free survival ... women with hormone-receptor-positive (HR+), human epidermal growth factor ... relapsed or progressed after endocrine therapy (median PFS, ...
Breaking Medicine Technology: