Gut Bacterium Lachnospira eligens Produces Metabolites That May Protect Against Muscle Wasting in Leukemia
Researchers found that Lachnospira eligens, a gut bacterium reduced in acute myeloid leukemia (AML) patients, produces fermentation metabolites—acetate, formate, and D-lactate—that counteract muscle atrophy in laboratory models. AML is associated with significant muscle wasting, and L. eligens abundance correlated positively with muscle strength in patients. The findings suggest that gut microbial metabolism and intestinal oxygen levels may play an underappreciated role in muscle health during serious illness.
A new preprint study published on bioRxiv investigated why patients with acute myeloid leukemia (AML) experience muscle wasting, focusing on the gut microbiome. The researchers found that L. eligens was consistently depleted across multiple independent AML patient cohorts and that its culture supernatant could prevent atrophy in mouse muscle cells (myotubes) stressed with dexamethasone or interleukin-6. Through metabolomic analysis and bioactivity-guided fractionation, the team identified acetate, formate, and D-lactate—products of mixed acid fermentation (MAF) under anoxic conditions—as the key anti-atrophic compounds. Supporting this mechanism, AML patients showed reduced blood acetate levels and an increased proportion of gut bacteria capable of aerobic respiration, which would compete for oxygen and suppress MAF. However, when bacterial supernatant was tested in a mouse leukemia model, it failed to prevent muscle atrophy or weakness, likely because blood levels of the acid metabolites were not sustainably elevated. The authors conclude that gut electron acceptor availability, particularly oxygen, may be a critical and overlooked factor in muscle-wasting disorders.
What's missing
As a preprint, this study has not yet undergone formal peer review. The mouse leukemia model did not recapitulate the in vitro anti-atrophic effects, raising unresolved questions about translational relevance and the feasibility of therapeutic delivery of these metabolites in vivo. The study does not address whether restoring L. eligens colonization or supplementing MAF end-products could be achieved safely in AML patients, nor does it examine potential confounders such as antibiotic use or chemotherapy effects on the gut microbiome.
What different sources said
- bioRxivCenter
Mixed acid fermentation products from Lachnospira eligens counteract myotube atrophy
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