Decreased gut microbiome-derived indole-3-propionic acid mediates the exacerbation of myocardial ischemia/reperfusion injury following depression via the brain-gut-heart axis

Despite the increasing recognition of the interplay between depression and cardiovascular disease (CVD), the precise mechanisms by which depression contributes to the pathogenesis of cardiovascular disease remain inadequately understood. The involvement of gut microbiota and their metabolites to health and disease susceptibility has been gaining increasing attention. In this study, it was found that depression exacerbated cardiac injury, impaired cardiac function (EF%: P<0.01; FS%: P<0.05), hindered long-term survival (P<0.01), and intensified adverse cardiac remodeling (WGA: P<0.01; MASSON: P<0.0001) after myocardial ischemia/reperfusion (MI/R) in mice. Then we found that mice receiving microbiota transplants from chronic social defeat stress (CSDS) mice exhibited worse cardiac function (EF%: P<0.01; FS%: P<0.01) than those receiving microbiota transplants from non-CSDS mice after MI/R injury. Moreover, impaired tryptophan metabolism due to alterations in gut microbiota composition and structure was observed in the CSDS mice. Mechanistically, we analyzed the metabolomics of fecal and serum samples from CSDS mice and identified indole-3-propionic acid (IPA) as a protective agent for cardiomyocytes against ferroptosis after MI/R via NRF2/System xc-/GPX4 axis, played a role in mediating the detrimental influence of depression on MI/R. Our findings provide new insights into the role of the gut microbiota and IPA in depression and CVD, forming the basis of intervention strategies aimed at mitigating the deterioration of cardiac function following MI/R in patients experiencing depression. Depression changed gut microbial richness and community structure, resulting in impaired tryptophan metabolism. The disorders of gut microbial composition and metabolism led to decreased levels of a series of metabolites, including IPA. Decreased serum IPA, which could protect cardiomyocytes against ferroptosis post MI/R via NRF2, mediated the detrimental influence of depression on MI/R. • Depression can exacerbate myocardial ischemia-reperfusion (MI/R) injury in mouse models. • The disturbance of gut microbiota and tryptophan metabolism mediate aggravated MI/R injury in depressed mice. • Decreased gut microbiome-derived indole-3-propionic acid (IPA) mediates the exacerbation of MI/R injury following depression • IPA supplementation can alleviate MI/R injury by inhibiting ferroptosis and oxidative stress through NRF2/System xc-/GPX4 axis.