We studied the response of vascular endothelial cells to unidirectional laminar flow through
collapsed veins. An original experimental set-up was developed, to generate and to map shear
stresses with local transverse gradients. This enabled us to detect changes in the shape of
endothelial cells when viscous fluid flow was applied. Porcine
vena cava endothelial cells
were seeded on a proof sample placed in the specifically designed flow chamber.
Postconfluent endothelial cells were continuously exposed to a maximum calculated wall
shear stress of 0.11 Pa (1.1 dyne/cm2)
and to a maximum calculated transverse gradient of
0.045 Pa/mm for 20 hours. This paper deals with the morphometry of single cells and the
angle of their major axes with respect to the flow direction. Cells in confluent monolayer
underwent a shear stress intensity-dependent change in shape with a decrease of shape index
from 0.55 to 0.34. The cells were not uniformly oriented in the direction of flow axes except
in the region of larger gradient. In this particular region, the cells had a low angle with respect
to the flow axes at some coordinates or exhibited reversal of their major and minor axes with
a doubling of cell area. These observations suggest that there have been specific cytoskeleton
rearrangements, associated with specific resultant forces over the cellular surface.