The Connection Between Inflammation and Impaired Motor Function

In a recent study, researchers have uncovered a significant link between inflammation and impaired motor function in fruit flies. This discovery has implications for the treatment of muscle fatigue following infections, particularly in the context of long COVID. Aaron Johnson, a developmental biologist at Washington University, explains that the reduction in energy levels in skeletal muscle due to inflammation can severely limit one’s ability to move and function normally.

With each new infection of the SARS-CoV-2 virus, the risk of developing long COVID increases. Nearly 18 million American adults have already experienced the lingering effects of this condition, including debilitating symptoms such as muscle fatigue and loss of energy. Interestingly, similar symptoms are observed in individuals with post-viral conditions and neurodegenerative diseases, all of which are characterized by inflammation of the central nervous system.

To understand how inflamed neurons can affect muscle function, researchers conducted experiments on animal models. They identified a signaling pathway between brain cells and muscles in both flies and mice that results in a decline in motor function. When exposed to COVID-associated proteins or other disease-related proteins, the test animals exhibited reduced muscle performance, even after the infection had been cleared. This suggests that the effects of inflammation on muscle function can be chronic and long-lasting.

In humans, inflammation triggers neurons to release the immune cytokine interleukin-6 (IL-6), which then travels to muscles via the bloodstream. IL-6 activates a cellular program called JAK-STAT, leading to a decrease in energy production by mitochondria in muscle tissues. Despite the damaging effects of this process on muscle function, researchers speculate that it may have evolved as a mechanism for the brain to reallocate resources during times of infection. Further research is needed to fully understand this complex process and its implications for overall health.

In their study, the research team successfully blocked the JAK-STAT pathway in flies using drugs, demonstrating that the process can be reversed. This finding is consistent with previous studies conducted in mice. IL-6 inhibitors, which have been effective in treating autoimmune diseases and severe COVID-19 cases, show promise in mitigating the effects of chronic cytokine signaling associated with long COVID. By targeting the communication between the brain and muscles, researchers believe that it may be possible to alleviate the physical symptoms of various chronic conditions.

While some questions remain unanswered, such as how SARS-CoV-2 enters the central nervous system to trigger inflammation, this new research provides valuable insights into the connection between inflammation and impaired motor function. By identifying the mechanisms through which brain inflammation affects the entire body, researchers hope to develop more targeted and effective treatments for individuals suffering from a range of chronic conditions. Ultimately, this research sheds light on the intricate relationship between our brains, inflammation, and physical well-being.