PMN arrest and transmigration on inflamed endothelium is inhibited by Rivipansel. Isolated human PMNs were perfused over IL-1β-stimulated human umbilical vein endothelial cell monolayers in a microfluidic flow chamber at physiological shear stress of 2 dynes/cm2. (A) PMN rolling to arrest and transmigration across human umbilical vein endothelial cell monolayers are superimposed. PMNs are phase bright until migration below endothelial monolayer, then become phase dark (marked by white arrows; scale bar, 10 μm). (B) PMN density, adherent on inflamed human umbilical vein endothelial cells measured after 2 minutes of shear flow. Arrest and TEM averaged from 5 fields of view represents mean ± SEM for 40 cells (n = 3 separate experiments). Significant differences are indicated for PMN arrest and TEM compared with stimulation and no shear condition. ***P < .001; **P < .01; *P < .05. (C) PMN rolling at 3 minutes, arrest, and TEM density on human umbilical vein endothelial cells at 7 min in the presence and absence of Rivipansel inhibition are superimposed. Data points represent mean ± SEM from 5 fields per condition (n = 4 separate experiments). Rolling (*), arrest ($), and TEM (#) significance (at P < .01) compared with untreated reported. (D) PMN arrest efficiency (number of PMNs captured/count in blood) of whole blood sheared over recombinant E-selectin/ICAM-1 for 4 patients treated for sickle cell disease before (t = 0) and after Rivipansel infusion (left y-axis) and average serum concentrations of Rivipansel after infusion (right y-axis). Each data point is the mean ± SEM of 5 to 11 fields of view along the centerline of the channel. ***P < .001; **P < .005; *P < .01 denote significance from baseline at t = 0). TEM, transendothelial migration.
