Implications of Systemic Hematocrit and the Endothelial Glycocalyx Layer on Microvascular Hemodynamics
The microcirculation consists of blood vessels smaller than 40 μm, namely arterioles, venuoles, and capillaries. Microvessels prove to be the primary location of oxygen delivery and transport in the circulation, and their analysis has many implications in the understanding and development of human disease. While the role of the microcirculation has been understated in the past, recent research has alluded to its increasing clinical relevance. The objective of this thesis is to provide insight into both the physiology and microvascular hemodynamics of the microcirculation by presenting in vivo data of well-known microcirculatory phenomena. The first chapter of this thesis presents a published study on the effects of the endothelial glycocalyx layer (EGL), a complex layer of proteoglycans and glycoproteins, on microvascular hemodynamics via its enzymatic degradation. The second chapter of this thesis presents work investigating the effects of systemic hematocrit on microvascular hemodynamics, particularly the effects of hemoconcentration and hemodilution on blood flow and the thickness of the arteriolar cell free layer. The final chapter of this thesis presents improved computer vision and image processing techniques developed to analyze the spatial variations in the arteriolar cell free layer within a single vessel. The data presented in this thesis, in addition to presenting experimental evidence for well-known microcirculatory phenomena observed in vivo, provide insight into the implications of microvascular hemodynamics in human disease.