The distribution of rolling neutrophils in venular convergences.

The aim of this study was to characterize the distribution of adherent leukocytes in branched venular convergences in vivo. Intravital microscopy was used to obtain video images of leukocyte adhesion in multiple branched sites in mouse cremaster muscle, during the mild inflammatory response induced by surgical preparation. The average number of cells/vessel length was obtained over several minutes for seven venular convergences with varying geometrical configurations. Results from this study demonstrate a strong tendency of leukocytes to adhere at junctional points between converging vessels. Different vessel configurations were studied and results were shown to be insensitive to precise vessel geometry. Thus, in post-capillary venules, leukocytes are most likely to adhere at points between converging vessels, regardless of the precise geometrical properties or configuration of the vessels. Hydrodynamic mechanisms due to flow behavior through convergences likely play a significant role in determining locations of cellular adhesion. Future work should concentrate on quantifying the relative contributions of hydrodynamic and biochemical mechanisms to aid in understanding disease processes and development of treatments or therapeutics.