The Gut–Oral–Skin–Heart Microbiota Axis and Oxidative Stress: Where Have We Been and Where Are We Going

Scientific interest in the relationship between cardiovascular disease and the human microbiome has grown substantially in recent years, with particular emphasis placed on the gut microbiota. Emerging evidence suggests, however, that distinct microbial niches-including the skin, oral cavity, and gut-may interact to influence cardiovascular homeostasis through shared pathogenic pathways, most notably oxidative stress and systemic inflammation. Intestinal dysbiosis has been strongly linked to the increased production of microbial metabolites such as trimethylamine N-oxide, which promotes endothelial dysfunction, oxidative imbalance, and atherogenesis. The oral microbiome has similarly been implicated in cardiovascular pathology through mechanisms encompassing chronic low-grade inflammation, transient bacteremia, and direct vascular colonization by pathogenic species. The contribution of the skin microbiome to cardiovascular risk remains less well defined; nevertheless, chronic inflammatory dermatoses-psoriasis in particular-have been consistently associated with elevated cardiovascular risk, a relationship potentially mediated by systemic immune dysregulation and oxidative stress. This review synthesizes current evidence on the gut-oral-skin-cardiac microbiome axis, underscoring the central role of oxidative stress as a convergent pathogenic mechanism and examining potential therapeutic implications. A more comprehensive understanding of these interconnected systems may inform the development of novel, microbiome-targeted strategies for the prevention and management of cardiovascular disease.