Effects of recirculating flow on U-937 cell adhesion to human umbilical vein endothelial cells

Abstract

We used a sudden-expansion flow chamber to examine U-937 cell adhesion to unactivated and tumor necrosis factor (TNF)-α-activated human umbilical vein endothelial cells (HUVEC) in recirculating flow. For both unactivated and TNF-α-activated HUVEC, U-937 cells exhibited transient arrests within ∼150 μm of flow reattachment. Few arrests occurred directly at the reattachment site. U-937 cell rolling was not observed. At all other locations within the recirculation zone, U-937 cells did not exhibit transient arrests or rolling. TNF-α activation increased the frequency of U-937 cell arrests near reattachment but did not change the median arrest duration. Numerically simulated cell trajectories failed to predict attachment near the reattachment point. Deviations between experiment and theory may result from the nonspherical shape and deformability of U-937 cells. These results demonstrate that U-937 cell transient arrests occur preferentially in the vicinity of the reattachment point in recirculating flow. Possible mechanisms for adhesion include low shear stress, curved streamlines, fluid velocity components normal to the endothelium, and formation of larger contact areas.

Neutrophils, lymphocytes, and monocytes exhibit diverse behaviors in transendothelial and subendothelial migrations under coculture with smooth muscle cells in disturbed flow

“…Several in vitro studies, including ours. 5,25,26 have shown increased adhesion of flowing WBCs to activated ECs in the vicinity of the reattachment point. One of the reasons for this regional propensity for adhesion could be a longer residence time of the cells delivered to the area and a higher near-wall concentration.…”

Acoustic sensor for monitoring adhesion of Neuro-2A cells in real-time

“…The mechanical forces are applied by means of a centrifugal acceleration (Channavajjala et al, 1997), or exposure of the cells to laminar shear flow (Barber et al, 1998). These methods do not account for cells that are weakly adhering to the surface and also they fail to measure adhesion under environmental conditions ideal to the cells.…”

Normal and shear stresses influence the spatial distribution of intracellular adhesion molecule-1 expression in human umbilical vein endothelial cells exposed to sudden expansion flow

“…1) consisted of polycarbonate plates separated by an aluminum gasket and was similar to chambers described previously (Truskey et al, 1995;Barber et al, 1998). For a given volumetric flow rate Q; fluid density r and dynamic fluid viscosity m; Reynolds number was defined as…”