Gut microbiome and chemotherapy-induced cardiotoxicity: A systematic review of evidence and emerging therapies

Chemotherapy-induced cardiotoxicity is a significant complication in cancer therapy, limiting treatment efficacy and worsening patient outcomes. Recent studies have implicated the gut microbiome and its key metabolites, such as short-chain fatty acids (SCFAs) and trimethylamine-N-oxide (TMAO), in mediating inflammation, oxidative stress, and cardiac damage. The gut-heart axis is increasingly recognized as a pivotal pathway linking microbiota dysregulation to chemotherapy-related cardiac dysfunction.

To systematically review existing evidence on the role of gut microbiome alterations in chemotherapy-induced cardiotoxicity and evaluate emerging microbiome-based therapeutic strategies aimed at mitigating cardiovascular risk in cancer patients.

A systematic literature search was conducted in PubMed, Scopus, and Web of Science for studies published between January 2013 and December 2024. Studies were included if they examined chemotherapy-induced cardiotoxicity in relation to gut microbiota composition, microbial metabolites (e.g., SCFAs, TMAO), or microbiome-targeted interventions. Selection followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data extraction focused on microbiota alterations, mechanistic pathways, cardiac outcomes, and quality assessments using standardized risk-of-bias tools.

Eighteen studies met the inclusion criteria. Chemotherapy was consistently associated with gut dysbiosis characterized by reduced SCFA-producing bacteria and increased TMAO-producing strains. This imbalance contributed to gut barrier disruption, systemic inflammation, and oxidative stress, all of which promote myocardial damage. SCFA depletion weakened anti-inflammatory responses, while elevated TMAO levels exacerbated cardiac fibrosis and dysfunction. Preclinical studies showed promising cardioprotective effects from probiotics, prebiotics, dietary interventions, and fecal microbiota transplantation, though human data remain limited.

Gut microbiome dysregulation plays a crucial role in the development of chemotherapy-induced cardiotoxicity. Altered microbial composition and metabolite production trigger systemic inflammation and cardiac injury. Microbiome-targeted therapies represent a promising preventive and therapeutic approach in cardio-oncology, warranting further clinical validation through well-designed trials.