Effect of Arteriolar Vasomotion on Network Flow

Abstract

BackgroundRhythmic, spontaneous change in microvascular diameter, vasomotion, is observed across numerous species and vascular beds. So far, a plausible physiological role for vasomotion remains to be established. It appears that vasomotion is more prevalent under conditions of insufficient perfusion, suggesting a protective role in hypoxia. Alternating reduction in diameter in some vessels could potentially cause increased perfusion in neighboring branches and ensure flushing of otherwise under‐perfused regions on a regular basis.MethodsFlow simulations were performed in virtual vascular networks. First, each vessel adapted structurally to local pressure and flow, as well as to the local capillary perfusion requirement. Subsequently, the mature network was exposed to low perfusion pressure, with or without the presence of vasomotion in selected branches.ResultsIn vasodilated networks forced diameter oscillations in one branch of a stem caused a 15% flow increase in the other branch from the same stem, independent of network perfusion pressure level. Allowing the network to develop a myogenic tone that matches the local network pressure, reduces the effect of forced diameter oscillation on flow in neighboring vessels; the higher the network perfusion pressure, the smaller is the effect of vasomotion. This is due to myogenic compensation in the non‐oscillating vessel. In all cases, however, total network flow was reduced by the presence of vasomotion.ConclusionVasomotion can increase flow locally in neighboring network regions. This effect is strongest under the low tone conditions likely to be present during tissue hypoxia. On a whole‐network level, however, the presence of vasomotion reduces, rather than increases, the flow.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.