The human muscle developed in the laboratory shows that exercise can “almost completely” prevent chronic inflammation that causes tissue to run out
- Inflammation stems from the overreaction of the body’s immune system
- Chronic inflammation can cause wasted muscle tissue and loss of structure
- Experts believe that a molecule called ‘gamma interferon’ is behind this waste
- However, it was not clear how this worked and why the exercise seemed to mitigate it.
- To investigate more simply, US researchers developed their own muscles in the laboratory
- This allowed them to focus on the cells to focus on the relevant processes
Exercise can “almost completely” prevent chronic inflammation that causes muscle wasting, a study of human tissue grown in the laboratory revealed.
Inflammation occurs when our body’s immune system responds to bacteria or tissue damage – but it can sometimes overreact and end up attacking its own cells.
And some diseases – like arthritis and sarcopenia – can lead to long-term ‘chronic inflammation’, which causes muscle wasting.
A molecule known as ‘gamma interferon’ is believed to be responsible for several types of muscle loss and dysfunction.
Previous studies have indicated that exercise can mitigate the effects of inflammation in general – but the role of muscle cells and gamma interferon is unclear.
To find this out, researchers at Duke University in the United States have developed a platform that allows them to develop their own human muscles in the laboratory.
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Exercise can “almost completely” prevent chronic inflammation that causes muscle wasting, a study of human tissue grown in the laboratory revealed. In the photo: long, thin and well-defined muscle fibers (upper left corner) lose their structure after prolonged inflammation (upper right corner), but not when also undergoing exercise (lower left corner). The same applies to force (bottom right)
“Many processes are taking place throughout the human body during exercise, and it is difficult to separate which systems and cells are doing what within an active person,” said article author and biological engineer Nenad Bursac.
“Our designed muscle platform is modular, which means that we can mix and match various types of cells and tissue components if we want.”
‘But in this case, we found that the muscle cells were able to exert anti-inflammatory actions on their own.’
For their studies, the researchers started by growing functional human skeletal muscle in a Petri dish – to which they added immune cells and stem cell reservoirs.
When the muscles were fully grown, the team ‘flooded’ them with high levels of gamma interferon for seven days to mimic the effects of long-lasting chronic inflammation.
As expected, the muscles developed in the laboratory became smaller and lost much of their strength.
They then repeated the experiment, but this time they put the muscles on a simulated exercise regime using electric shocks.
The regime “almost completely” prevented the effects of chronic inflammation by blocking a specific molecular pathway, the researchers found.
“We know that chronic inflammatory diseases induce muscle atrophy, but we wanted to see if the same thing would happen with our human muscles developed in a petri dish,” said article author and biomedical engineer Zhaowei Chen.
“We not only confirmed that gamma interferon works primarily through a specific signaling pathway,” he continued.
“We have shown that muscle cells in exercise can directly combat this proinflammatory signaling regardless of the presence of other types of cells or tissues.”
The exercises have the same anti-inflammatory effect as tofacitinib and baricitinib, two drugs commonly used to treat arthritis, the researchers found.
“During exercise, the muscle cells themselves were directly opposed to the pro-inflammatory signal induced by gamma interferon, which we did not expect to happen,” said Professor Bursac.
‘These results show just how valuable human muscles grown in the laboratory can be in discovering new disease mechanisms and potential treatments.
“There are notions out there that ideal levels and regimes of exercise can fight chronic inflammation without overloading cells.”
‘Perhaps with our projected muscles, we can help to find out if such notions are true.’
The full results of the study were published in the journal Science Advances.