The impact of fluid shear stress on the morphology of human dermal microvascular endothelial cells
AdvisorLong, David S.
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As blood flows through blood vessels, the fluid exerts a shear stress on the endothelial cells that line the vasculature. The current perception in the literature is that all endothelial cells will align and elongate in the direction of applied fluid shear stress. This response to fluid shear stress has been observed primarily in endothelial cells that line larger blood vessels, with little information on the response of microvascular endothelial cells. A few recent studies have found that some microvascular endothelial cells respond differently than larger endothelial cells, but there is still little information on the response of most microvascular endothelial cell types. Therefore, this study investigated the morphological response of human dermal microvascular endothelial cells (HMEC-1) to steady, unidirectional, and laminar flow resulting in fluid shear stresses of 0.3, 16, and 32 dyn/cm2. Confluent monolayers of HMEC-1 were exposed to fluid shear stress for 73 hours. Images of the live cell membrane and stained nuclei were captured hourly across the slide. These images were then processed and segmented using FIJI to calculate five morphological parameters: orientation with respect to flow direction, inverse aspect ratio, circularity, area, and perimeter. The results of this study demonstrate the complex morphological response of HMEC-1 that is dependent on fluid shear stress as it increased above 16 dyn/cm2. HMEC-1 showed a slight increase in elongation and alignment from 0.3 to 16 dyn/cm2. There was a decrease in elongation and no change in alignment as fluid shear stress increased further from 16 to 32 dyn/cm2. This novel, preliminary study contributes to filling the gap in the literature on the response of microvascular endothelial cells to fluid shear stress. Future work could investigate the mechanisms behind this morphological response through analysis of cytoskeletal reorganization and genetic regulation of functional HMEC-1 genes, such as those involved in angiogenesis.
Thesis (M.S.)-- Wichita State University, College of Engineering, Dept. of Biomedical Engineering