Barosensory vessel mechanics and the vascular sympathetic baroreflex: Impact on blood pressure homeostasis

Abstract

New Findings What is the topic of this review? We review barosensory vessel mechanics and their role in blood pressure regulation across the lifespan. What advances does it highlight? In young normotensive men, aortic unloading mechanics contribute to the resting operating point of the vascular sympathetic baroreflex; however, with advancing age, this contribution is removed. This suggests that barosensory vessel unloading mechanics are not driving the well‐documented age‐related increase in resting muscle sympathetic nerve activity. AbstractAn age‐associated increase in arterial blood pressure is evident for apparently healthy humans. This is frequently attributed to stiffening of the central arteries and a concurrent increase in sympathetic outflow, potentially mediated by a reduced ability of the baroreceptive vessels to distend. This is supported, in part, by a reduced mechanical component of the vascular sympathetic baroreflex (i.e., a reduction in distension for a given pressure). Previous characterization of the mechanical component has assessed only carotid artery distension; however, evidence suggests that both the aortic and carotid baroreflexes are integral to blood pressure regulation. In addition, given that baroreceptors are located in the vessel wall, the change in wall tension, comprising diameter, pressure and vessel wall thickness, and the mechanics of this change might provide a better index of the baroreceptor stimulus than the previous method used to characterize the mechanical component that relies on diameter alone. This brief review summarizes the data using this new method of assessing barosensory vessel mechanics and their influence on the vascular sympathetic baroreflex across the lifespan.

Causes and consequences of sympathoexcitation across the lifespan: Physiological or pathological?

“…to poorer baroreceptor function in later life. Their review (Hughes et al, 2023) discusses how recent advancements in vascular ultrasound methods can be used to quantify parameters of baroreceptor function, such as rate of unloading and time spent unloaded. Using these novel techniques, Lord et al (2020) found that baroreceptor unloading mechanics were indeed altered in older age, with a reduced rate of unloading and less time spent unloaded observed in older versus younger healthy males.…”

“…Recent work by Rachel Lord and colleagues has provided insight into whether the age‐related rise in sympathetic nerve activity is related to poorer baroreceptor function in later life. Their review (Hughes et al., 2023 ) discusses how recent advancements in vascular ultrasound methods can be used to quantify parameters of baroreceptor function, such as rate of unloading and time spent unloaded. Using these novel techniques, Lord et al.…”