The long-term maintenance of patients with failing hearts on cardiac prostheses requires prevention of device related thromboembolic events. This challenge is being addressed by endothelialization of the blood sacs. However, the practice of establishing and maintaining a durable endothelial cell monolayer inside a beating prosthesis has not been fully realized. Thus, before exposing endothelial cell monolayers to the hemodynamics inside an artificial heart, the authors studied the effect of various flow patterns in a ventricle shaped chamber on the integrity and morphology of the en-dothelium. After 20 hours of superfusion by pulsatile flow, there were no denudation signs in the jet, where shear stress was 1.5 dynes/cm2. However, there was measurable damage to the monolayer close to the periphery of the eddies (turbulent flow) at 0.15 dynes/cm2. In either case, there were no signs of cell alignment with the flow, but there were changes in cell morphology compared with that of static control. These findings suggest that adjustment of endothelial cells in response to frictional forces occurs even at low shear stresses and that random velocity fluctuations might jeopardize the integrity of endothelial cell monolayers.
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