Exercise drives muscles to fight chronic inflammation on their own
Inflammation in the human body is a complex physiological response to a complex range of triggers, and scientists have just uncovered some useful new details about how it works by experimenting with muscles grown in the lab. By simulating the effects of exercise on these engineered cells and tissues, the scientists made the unexpected discovery that human muscle can fend off inflammation all on its own.
While it is taken as a given that exercise is good for the body in all kinds of ways, research is starting to show us how it can specifically temper the effects of inflammation, through studies on our knees and gut microbiome, for example. Biomedical engineers at Duke University set out to explore the more precise mechanisms behind this by using a cutting edge research tool.
“Lots of processes are taking place throughout the human body during exercise, and it is difficult to tease apart which systems and cells are doing what inside an active person,” said Nenad Bursac, professor of biomedical engineering at Duke. “Our engineered muscle platform is modular, meaning we can mix and match various types of cells and tissue components if we want to. But in this case, we discovered that the muscle cells were capable of taking anti-inflammatory actions all on their own.”
The team made this discovery by conducting experiments involving a pro-inflammatory molecule called interferon gamma, which has been linked to muscle wasting-related conditions. The lab-grown muscles were subjected to high levels of this molecule over seven days to simulate chronic inflammation, which as expected caused them to become smaller and lose a lot of their strength.
Next, the scientists repeated this experiment but stimulated the artificial muscle with a pair of electrodes to mimic the effects of exercise. To their surprise, this almost completely negated the effects of the chronic inflammation. Further investigations showed that this simulated exercise blocked a certain molecular pathway in the muscle cells.
“When exercising, the muscle cells themselves were directly opposing the pro-inflammatory signal induced by interferon gamma, which we did not expect to happen,” said Bursac. “These results show just how valuable lab-grown human muscles might be in discovering new mechanisms of disease and potential treatments. There are notions out there that optimal levels and regimes of exercise could fight chronic inflammation while not overstressing the cells. Maybe with our engineered muscle, we can help find out if such notions are true.”
The research was published in the journal Science Advances, while the video below offers side-by-side look at the muscles used in the experiments, which fluoresce when calcium levels spike, an indicator of strength.
Source: Duke University