According to traditional Chinese medicine (TCM) constitutional theory, individuals with phlegm-dampness constitution (PDC) are at increased risk for metabolic disorders. Previous studies have indicated that PDC individuals exhibit gene expression changes associated with metabolic disorders, even individuals with normal metabolic indices. However, the biological mechanisms underlying these changes remain unclear. The gut microbiota has recently emerged as a promising avenue for elucidating TCM principles. Here, we revealed that individuals with PDC have distinct gut microbiota and serum metabolite profiles. A decrease in phytosphingosine was associated with increased PDC scores and metabolic disorder severity. Subsequent experiments demonstrated that Flavonifractor plautii can biosynthesize phytosphingosine, which was also negatively correlated with the PDC score. Interestingly, both F. plautii and phytosphingosine levels decreased in PDC subjects with normal metabolic indices. Fecal transplantation from these individuals accelerated the development of metabolic disorders in mice. However, supplementation with F. plautii and phytosphingosine ameliorated metabolic disorders by increasing phytosphingosine levels in the gut‒hepatic axis. Mechanistic investigations confirmed that phytosphingosine can directly bind to hepatic peroxisome proliferator-activated receptor α (PPARα) and activate its nuclear transcription activity, thereby regulating downstream gene expression related to glucose‒lipid metabolism. Our research indicates that the decrease in F. plautii and its product, phytosphingosine, contributes to gene expression changes related to metabolic disorders in PDC individuals and increases their susceptibility to metabolic disorders. These findings suggest that diagnosing PDC may be beneficial for identifying at-risk populations among apparently healthy individuals, thereby advancing the broader field of metabolic disorder prevention and TCM integration.
Myocardial ischemia/reperfusion (I/R) injury is a major contributor to myocardial damage, leading to adverse cardiac remodeling and dysfunction. Recent studies have highlighted the potential of gut microbiota-derived metabolites in modulating cardiac outcomes. Here, the cardioprotective effects of a commensal bacterium Flavonifractor plautii ( F. plautii ) and its metabolite desaminotyrosine (DAT) against myocardial I/R injury are investigated. We showed that prophylactic gavage of F. plautii attenuates myocardial I/R injury as evidenced by improved cardiac function and reduced cardiac injury. We also found that its metabolite DAT recapitulates these cardioprotective effects against myocardial I/R injury. Transcriptomic analysis has revealed that DAT preserves cardiac tissue and attenuates immune responses against myocardial I/R injury. Mechanistically, DAT promotes cardiomyocyte survival through the modulation of the nicotinamide adenine dinucleotide phosphate (NADP + /NADPH) ratio. Further, DAT suppressed macrophage proinflammatory activities and cardiac inflammation via the reduction in interleukin-6 (IL-6) production. Taken together, our findings indicate that F. plautii and its metabolite DAT exert pleiotropic cardioprotective effects against myocardial I/R injury, suggesting them as potential prophylactic therapeutic options for alleviating myocardial I/R injury.