Are an Aging Gut and a Decrease in Butyrate Production the Reasons for Atherosclerosis?

Atherosclerosis (AS) is directly linked to the aging and damage of endothelial cells (ECs). As ECs and vascular smooth muscle cells (VSMCs) age, more autocrine and paracrine signals are released, extending a vicious cycle of tissue aging and physiological dysfunction. The recruitment of immune cells to inflamed arteries, including coronary arteries, and an increase in the uptake of oxidised low-density lipoprotein (ox-LDL) by macrophages (foam cells) onto the tunica intima (intima) of coronary arteries restrict blood flow. The inability of aging and damaged ECs to accommodate vast changes in signalling molecules, many produced by gut microbiota, leads to a range of anatomical and physiological arterial anomalies. These include degradation of cardiovascular membranes, fibrosis, calcification, plaque formation, and an increasingly dysfunctional immune system. Changes in the gut microbiome of the elderly have a direct effect on the immune response, as the signalling molecules produced by gut microbiota target specific receptors on inflamed arteries. This review summarizes the anatomical and physiological changes associated with the aging of coronary arteries and emphasizes the conditions leading to AS. The importance of butyrate-producing gut microbiota in preventing AS, especially in the elderly, is discussed.