Affiliations:
Department of Medical Laboratories, School of Health Sciences, Technological Educational Institute (TEI) of Thessaly, Larissa, Greece
Correspondence:
[*]
Corresponding author: Aristotle G. Koutsiaris, Department of Medical Laboratories, School of Health Sciences, Technological Educational Institute (TEI) of Thessaly, Larissa 41 110, Greece. Tel.: +30 2410 411284; E-mail: ariskout@teilar.gr.
Abstract: Wall shear stress (WSS) is a very important hemodynamic parameter implicated in many physiological and pathological phenomena. In order to study these phenomena, it is more convenient to use in vitro models before testing on animals and humans. Dynamic in vitro cerebrovascular models are considered capable of simulating the in vivo hemodynamic conditions, but only few of them seem to meet the criteria for this task. It is now clear that in the human eye microcirculation a significant pulsation exists at the pre-capillary arterioles with average WSS values more than twice those in the venular side, for the same diameters. WSS heterogeneity is in support of segmental heterogeneity i.e. the endothelial phenotypic and functional difference among arterioles, capillaries and venules. In this review paper, the importance of WSS is described in detail and two more microvascular segments are proposed: a pre-capillary arteriolar and a post-capillary venular segment. The accurate hemodynamic simulation in all microvascular segments seems to be a prerequisite step in the development of dynamic in vitro blood brain barrier (BBB) models and microfluidic platforms on chip. Endothelial cells in the cardiovascular system seem to have sophisticated role acting like cardiovascular processing sensors (CPSs).
Keywords: Wall shear stress, hemodynamics, human microcirculation in vivo, segmental heterogeneity, in vitro cerebrovascular models, blood-brain barrier, microfluidics
