More and more studies are finding that gut microbiota in humans and other animals is linked to all sorts of heath factors and bodily functions. The role of the microbiome in maintaining good health is huge. Research has found that it doesn’t only process food, but it plays a big part in immunity and in regulating cholesterol and triglycerides, among other things.
And while a healthy microbiome enhances well-being, an imbalance in the gut microbiota on the contrary has a negative effect. For instance, it has been associated with conditions such as Crohn’s disease, IBS and other inflammatory diseases, as well as obesity, multiple sclerosis, Parkinson’s, and mental health issues like depression and anxiety. Now, a new study by an international team of researchers provides evidence that suggests the gut microbiome also plays a role in maintaining the right amount of skeletal muscle mass and its function—at least in mice.
The team led by Nanyang Technological University (NTU), Singapore found that the gut microbiota in mice influence their skeletal muscle – the collection of muscles that are connected to bones in the skeleton that control movement, most specifically, the limbs. They describe their experiments with wild and lab-raised mice, and what they found in a paper published in the journal Science Translational Medicine.
The Experiments
- The subjects included several wild mice and germ-free mice – which are mice with no microbiome at all.
- They compared the two types and found that the germ-free mice: had atrophied skeletal muscles; they expressed fewer chemicals that support muscle growth; they had higher-than-normal levels of multiple amino acids—a sign of liver problems; and they had lower levels of a precursor to a neurotransmitter called acetylcholine – which is involved in transmitting signals between skeletal muscle and nerves.
- Next, they transplanted gut microbiota containing material from wild mice into the guts of germ-free mice to see what would happen – it resulted in an increase in muscle mass and function.
- They also gave the germ-free mice fatty acids that are produced normally by microbes in the gut to see what would happen – it partially restored muscle mass.
Professor Sven Pettersson from the NTU Lee Kong Chian School of Medicine, who led the study, said:
These results further strengthen the growing evidence of gut microbes acting as crucial gatekeepers to human health, and provide new insight into muscle mass maintenance with respect to ageing. They lay the foundation for future studies that evaluate how microbes and their metabolites may be potential targets of intervention to improve skeletal muscle strength in the elderly, especially in countries such as Singapore with rapidly ageing populations.
While additional experiments are needed to fully obtain the mechanisms underlying muscle atrophy and dysfunction in the nerve-muscle junction in germ-free mice, the results presented here allow for important and interesting future studies relevant to muscle development, growth and formation of functional nerve-muscle communication.
Professor of microbiology Wang Yue from Singapore’s Agency for Science, Technology and Research (A*STAR), who was not involved in the study, added:
This line of research will lead to novel ways to maintain or improve muscle mass, strength, and function by modulating the microbial composition in the gut. Such strategies are expected to have broad applications in tackling muscle-related health issues. One area with enormous potential is to delay or reverse age-related sarcopenia (the loss of skeletal muscle mass and strength as a result of ageing).
So, although the experiments only show the gut and skeletal muscle link in mice, the discovery is still inspirational for scientists and clinicians. It shines a light on the fact that there is something to investigate in the relationship between the microbial composition of the microbiota and the state of skeletal muscles in humans.
