Scientists identify key to maintaining muscle strength as we age

AN enzyme has been identified as necessary for staying strong through old age and its recent discovery could have an impact on exercise programs and the use of existing drugs as researchers work towards switching it on.
Loss of muscle strength occurs with age for reasons that appear misunderstood, but the discovery by scientists at McMaster University could offer promise towards warding off the less-than-desirable consequence of aging.
The enzyme is called AMP-activated protein kinase (AMPK) and it is best known for its role in cellular energy homeostasis, functions of which include regulating the cellular uptake of glucose.
"We found that the body's fuel gauge, AMP-activated protein kinase (AMPK), is vital to slow muscle wasting with aging," says Dr. Gregory Steinberg, the study's senior author and professor of medicine at the Michael G. DeGroote School of Medicine.
His previous research has indicated that AMPK is activated with exercise and commonly used medications such as metformin, the first-line drug of choice for treating type 2 diabetes, and salicylate, which is the active ingredient in aspirin.
Working with mice, Dr. Steinberg and his colleagues found that a lack of AMPK in the muscle led to significantly increased weakness than normal for middle-aged mice.
The mice that were the human equivalent to being 50 years old had muscles that resembled those of inactive 100-year-olds.
"It is known that AMPK activity in muscle is 'dialed down' with aging in humans, so this may be an important cause of muscle loss during aging," says Steinberg.
Currently, the only treatment available is exercise, which could be more important with age than we know.
What's more, the exercise should be intense, says Dr. Steinberg, whose study was published in the journal Cell Metabolism.
"By knowing that AMPK is vital for maintaining muscle mass with aging, we can now try to adapt exercise regimes and existing drugs to switch on AMPK in muscle more effectively," says Steinberg.
Age-related muscle wasting and loss of strength can not only shorten lives, it is also an escalating problem in aging populations such as that of Canada from where the research team hails.
Research has uncovered a waft of health benefits of the anti-diabetic drug metformin and a recent study indicating it could slow aging and even increase lifespan has healthcare professionals in the talks to find new roles for the drug. – AFP Relaxnews