Effect of vasomotion on blood flow distribution in microvessels

Abstract

The control of flow in the microcirculation is crucial to ensure blood supply to the tissues. The spontaneous time-dependent contraction and relaxation of small arteries and arterioles was observed 160 years ago and is termed as vasomotion. Vasomotion is an intrinsic phenomenon unrelated to cardiac rhythm or neural and hormonal regulation; and it works as a local control mechanism to regulate the microvascular blood flow. In spite of tremendous studies on vasomotion, the physiological role of vasomotion is not clear. Vasomotion results in the flow oscillation which is termed as flowmotion. The flowmotion is crucial for optimal blood flow and nutrient delivery in micro vasculature. Blood vessels in tumors are highly irregular and dense compared to those in normal tissue which may affect the flowmotion. As the first attempt, in this study we investigated the effect of irregular microvascular structure on flow delivery in microvascular bed with composite flow oscillating frequencies. The results showed that the irregular micro vasculature would decrease the flowmotion and lead to reduction of nutrient and drug delivery which is consistent with the experimental observation.