  Reduced blood flow, as occurring in ischemia or resulting from exposure to
microgravity such as encountered in space flights, induces a decrease in the
level of shear stress sensed by the endothelial cells forming the inner part of
blood vessels. In the present study, we use a microvasculature-on-a-chip device
in order to investigate in vitro the effect of such a reduction in shear stress
on shear-adapted endothelial cells. We find that, within one hour of exposition
to reduced wall shear stress, human umbilical vein endothelial cells undergo a
reorganization of their actin skeleton, with a decrease in the number of stress
fibers and actin being recruited into the cells' peripheral band, indicating a
fairly fast change in cells' phenotype due to altered flow.
