If you're one of the 13% of American adults who has taken a GLP-1 drug for weight loss, you may know that while fat seemingly melts away, so too does muscle. And if you're not one for weights, or have other conditions preventing a new training regimen, there's not a whole lot you can do about it.
But scientists from the Salk Institute have now identified a molecule that could potentially be boosted to help in this department. They found that a protein known as BCL6 is in charge of maintaining muscle structure – and by increasing its presence, it could stop the tissue from deteriorating without compromising any weight loss.
“Muscle is the most abundant tissue in the human body, so its maintenance is critical to our health and quality of life,” said Ronald Evans, a professor and director of the Gene Expression Laboratory at Salk. “Our study reveals how our bodies coordinate the upkeep of all this muscle with our nutrition and energy levels, and with this new insight, we can develop therapeutic interventions for patients losing muscle as a side effect of weight loss, age, or illness.”
The discovery, of course, goes beyond those taking GLP-1 medications. And while the BCL6 discovery came through a study on mice, researchers are confident it will translate to human physiology.
Investigating the mechanisms involved in periods of fasting, when the stomach and brain communicate to promote the secretion of a growth hormone directed at muscle cells, the researchers discovered that this chain reaction reduced BCL6 levels. If BCL6 is depleted, it essentially leads to a weakening and shrinking of muscle tissue structures.
When researchers increased BCL6 levels, the muscle tissue was resistant to this process – so weight loss would come from fat instead. In the mice study, the team found that without this BCL6 boost, the rodents had 40% less muscle mass than the control cohort. The muscle that they retained was also structurally poor and weaker. Then when the BCL6-suppressed mice were boosted with the protein, it reversed the muscle loss and strength.
And in fasting mice, BCL6 was significantly depleted in as short a time frame as overnight.
“We are excited to reveal BCL6’s important role in maintaining muscle mass,” said first author Hunter Wang, a postdoctoral researcher in Evans’ lab. “These were very surprising and special findings that open the door for a lot of new discoveries and potential therapeutic innovations.”
The researchers believe this discovery paves the way for the development of a BCL6 booster that could be given with the GLP-1 medication, to protect against muscle loss. In the meantime, the team plans to look into the effects of longer fasting periods and its impact on muscle tissue. This same kind of BCL6 therapy has the potential to help a wider population, such as older adults and those with muscle-impacting conditions including cancer.
The research was published in the journal Proceedings of the National Academy of Sciences.
Source: Salk Institute
