lancastria.net

SCIENTISTS have discovered how to reverse the “biological clock” by making human muscles younger and stronger.

The breakthrough, revealed last night, means they may be able to create a drug that rejuvenates old muscles and prevents young muscles from ageing.

For the first time, the chemical “switch” that keeps our muscles healthy has been pinpointed.

A team in America has shown that this process appears to turn-off in elderly patients – preventing the fibres from repairing themselves so they begin to wither away.

But when the switch is turned back on, it triggers a chain of events that allows muscles to rejuvenate.

The U.S. and Danish researchers studied the ability of stem cells – ‘master cells’ that repair damaged tissue – to build muscle.

They found that as we age, the chemical messages that tell the stem cells to get to work become weaker.

As a result, the body takes longer to repair the damage.

Chest muscle structure

Their findings, reported in the journal EMBO pave the way for a pill that magnifies the messages – and so strengthens muscles.

The researchers worked on pieces of muscle cut from the thighs of young men, aged between 21 and 24, and older men aged between 68 and 74.

After the samples were taken, the men had the leg that was being studied put in plaster to make the remaining muscle weaken.

When the casts were taken off, the men exercised with weights to rebuild their muscles and more samples were removed.

Before exercising, the young men had twice as many muscle-repairing stem cells as the older men.

Analysis of the samples revealed a protein called mitogen-activated protein kinase (known as MAPK) to be key to the process.

It helps send signals that tell stem cells to multiply and start repairing damaged muscle but levels fall with age.

When the scientists boosted the amount of MAPK in old muscle, it regained its ability to regenerate.

A drug that does the same could one day be given to people while they are still relatively young to ensure they remain as strong as possible in their 60s, 70s and 80s.

One researcher said: ‘Our study shows that the ability of old human muscle to be maintained and repaired by muscle stem cells can be restored to youthful vigour given the right mix of biochemical signals.’

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