In straight segments of the blood vessel, the endothelium is aligned and the endothelial cells are resistant to inflammation and thrombosis. At bends and branches of the vessel where the endothelium is not aligned, however, the endothelial cells express adhesion molecules and chemokines that promote the adherence of platelets and leukocytes, leading to atherosclerosis. In this study, we aim to investigate the effects on the morphology and biology of endothelial cells due to the presence of an aligned matrix, with and without the presence of shear flow. Although it is known how shear flow can influence endothelial cells, the combination of matrix-controlled alignment and shear flow on endothelial biology (and morphology) is relatively unknown. While the phalloidin alignment and assembly of focal adhesions will help characterize the morphological effects on the cells, their biological function will also be evaluated. Proliferation, monocyte adhesion and integrin signaling are a few of the biological indicators of the endothelial cells that can indicate the effects of matrix-induced alignment and shear flow.
Endothelial cells are cultured onto aligned and unaligned collagen substrates and then exposed to a continuous period of shear flow, perpendicular to the direction of collagen alignment. Afterwards, the morphology and biology of the endothelial cells are evaluated. Cells cultured on aligned collagen demonstrate a resistance to re-aligning themselves along the shear flow direction, while cells on unaligned collagen tend to elongate along the direction of shear flow. It is also expected that the endothelial cells on aligned collagen will express less adhesion molecules that prevent the adherence of monocytes. These observations may be especially significant in the development of vascular conduits, since endothelial cells are generally healthier if they can maintain their aligned orientation despite the turbulence of surrounding blood flow.