Cardiovascular disease and microbiome: focus on ischemic stroke.

Cardiovascular and cerebrovascular diseases, encompassing conditions such as ischemic heart disease and ischemic stroke (IS), remain the leading global cause of death and disability. While traditional cardiovascular risk factors (eg, hypertension, diabetes, and atherosclerosis) are well established, emerging research underscores the critical role of gut microbiota in the development and progression of both cardiac and cerebrovascular events. The microbiota-gut-brain axis is a bidirectional communication system involving neural, immune, and metabolic pathways that link gut microbial activity to vascular and brain function. Dysbiosis, marked by reduced microbial diversity and an imbalance between beneficial and pathogenic taxa, has been associated with systemic inflammation, endothelial dysfunction, increased intestinal permeability, and thrombosis. Microbial metabolites, such as trimethylamine N‑oxide (TMAO), short‑chain fatty acids, and bile acid derivatives modulate blood-brain barrier integrity, vascular tone, and neuroinflammatory responses. Both cardiovascular and cerebrovascular diseases share key microbiota‑related mechanisms, including TMAO‑mediated platelet activation and low‑grade endotoxemia, although IS is more acutely affected by gut barrier disruption and neuroinflammation. In IS, gut dysbiosis also contributes to poststroke complications, such as hemorrhagic transformation, neuropsychiatric issues, and epilepsy. Advances in sequencing and metabolomics enabled identification of microbial signatures associated with the risk for an acute ischemic event and patient prognosis. Therapeutic strategies targeting the gut microbiota-including dietary interventions, probiotics, prebiotics, and synbiotics, fecal microbiota transplantation, and intestinal epithelial stem cell therapy-show promise in mitigating vascular injury and improving recovery. This narrative review highlights current insights into microbiota‑related cardiovascular and cerebrovascular events, with a focus on IS.