International study identifies muscle-wasting process

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Drugs could one day be used to reverse the muscle-wasting effects of ageing.

Scientists from King’s College London and Massachusetts General Hospital in the US have identified a key process responsible for muscle weakening in old age and used a chemical to block it in mouse studies.

Their findings , published in the latest online issue of the journal Nature, could pave the way to body-building anti-ageing drugs that keep people strong and fit towards the end of their lives.

The two teams of researchers looked at the way stem cells in muscle repair damaged tissue by dividing and developing into numerous new muscle fibres.

Strenuous activity, such as lifting weights, results in minor damage that triggers this response and builds up muscle.

The end result is bulging biceps and rippling torsos.

However, as people age, muscle loses its ability to regenerate itself – leading to limbs that become puny and weak.

Studying mice, the researchers found that the number of dormant stem cells in muscle reduces with age. They traced the effect to excessively high levels of FGF2 (fibroblast growth factor 2) – a protein that stimulates cells to divide.

In ageing muscle, the protein was continuously awakening the dormant stem cells for no reason.

The supply of stem cells depleted over time, so not enough were available when they really were needed.

As a result, the ability of muscle to regenerate was impaired.