Sitting leg vasculopathy: potential adaptations beyond the endothelium

Am J Physiol Heart Circ Physiol. 2024 Jan 19. doi: 10.1152/ajpheart.00489.2023. Online ahead of print.ABSTRACTIncreased sitting time, the most common form of sedentary behavior, is an independent risk factor for all-cause and cardiovascular disease mortality; however, the mechanisms linking sitting to cardiovascular risk remain largely elusive. Studies over the last decade have led to the concept that excessive time spent in the sitting position, and the ensuing reduction in leg blood flow-induced shear stress, causes endothelial dysfunction. This conclusion has been mainly supported by studies using flow-mediated dilation in the lower extremities as the measured outcome. In this mini-review, we summarize evidence from classic studies and more recent ones that collectively support the notion that prolonged sitting-induced leg vascular dysfunction is likely also attributable to changes occurring in vascular smooth muscle cells (VSMC). Indeed, we provide evidence that prolonged constriction of resistance arteries can lead to modifications in the structural characteristics of the vascular wall, including polymerization of actin filaments in VSMC and inward remodeling, and that these changes manifest in a timeframe that is consistent with the vascular changes observed with prolonged sitting. We expect this review will stimulate future studies with a focus on VSMC cytoskeletal remodeling as a potential target to prevent the detrimental vascular ramifications of too much sitting.PM...
Source: American Journal of Physiology. Heart and Circulatory Physiology - Category: Physiology Authors: Source Type: research