This review paper provides an overview of what is known and theorized of the influence of the gut microbiome on the aging of the vasculature. Cardiovascular disease is the largest cause of human mortality, and there is considerable interest in better understanding how to slow its onset, given the lack of progress towards meaningful reversal of conditions such as atherosclerosis. The relative abundance of populations in the gut microbiome change with age in ways that (a) diminish the production of beneficial metabolites, and (b) provoke chronic inflammation. It is most likely primarily this latter point that drives issues in the vasculature, given the strong evidence for chronic inflammation to drive the progression of cardiovascular disease. That said, as noted here, direct correlations between the microbiome and some of the preferred measures of vascular aging have yet to be established, or are not in evidence.
The gut microbiota is a critical regulator of human physiology, deleterious changes to its composition and function (dysbiosis) have been linked to the development and progression of cardiovascular diseases. Vascular ageing (VA) is a process of progressive stiffening of the arterial tree associated with arterial wall remodeling, which can precede hypertension and organ damage, and is associated with cardiovascular risk. Arterial stiffness has become the preferred marker of VA.
In our systematic review, we found an association between gut microbiota composition and arterial stiffness, with two patterns, in most animal and human studies: a direct correlation between arterial stiffness and abundances of bacteria associated with altered gut permeability and inflammation; an inverse relationship between arterial stiffness, microbiota diversity, and abundances of bacteria associated with most fit microbiota composition.
Interventional studies were able to show a stable link between microbiota modification and arterial stiffness only in animals. None of the human interventional trials was able to demonstrate this relationship, and very few adjusted the analyses for determinants of arterial stiffness. We observed a lack of large randomized interventional trials in humans that test the role of gut microbiota modifications on arterial stiffness, and take into account blood pressure and hemodynamic alterations.