New research muscles up on immobility

Regaining your mobility or strength back after illness or injury gets harder as we get older but this could be about to change.

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Exercise, particularly weight bearing activities, helps retain and build muscles and strength.

This is particularly important as one ages, and unfortunately, injury or illness, which are likely in older people, can lead to periods of immobility and declines in muscle quality.

If that goes on for too long then there's going to be significant loss of muscle mass and strength.

The muscles of children and younger adults tend to recover quickly after resuming exercise but that’s not the case for older adults. This is due to the underlying biological mechanisms that support our strength and mobility becoming less effective as we age.

It’s not good news for those who think physical therapy promotes healing after injury and immobility. Sadly, studies show that muscle in older people continues to deteriorate after exercise.

Researchers from the University of Illinois Urbana-Champaign say it’s got to do with inflammation and cellular dysfunction accumulating in the muscles, which impedes the healing process.

The research team discovered that injections of support cells known as pericytes contributed to muscle recovery in young mice after a period of immobility. However, aged mice did not respond as well to the injections, and recovery was limited.

In a new study, the team collected pericytes from the muscles of young, healthy mice and grew them in cell culture. They exposed the cells to hydrogen peroxide – a powerful oxidant that promotes the production of extracellular vesicles (EV), which help to combat stress and enhance healing. They then collected the EVs produced in response to the hydrogen peroxide to use therapeutically.

They found that EVs collected from the blood of young mice and injected into aged mice produced “a younger collection of traits”. They also found that healthy EVs introduced into diabetic mice reversed their diabetes.

Muscle recovery discovery

The research team found both the younger and older mice treated with the stimulated EVs recovered muscle. The study also revealed – for the first time – that EVs derived from muscle pericytes produced factors that may combat inflammation.

Early studies suggest that animals do not mount an immune response to injected EVs, but more research is needed to test those findings.

“Until this study, we had no idea how the pericytes were working," Boppart said. "We just knew that they were secreting beneficial factors that likely helped the recovery process. Now we have a much better grasp of the mechanism by which they do this. And we know how to stimulate them to do it better."

Source: Science Daily

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