Figure 4.

Polymorphonuclear leucocyte (PMN) reactive oxygen species (ROS) released in response to complement component 5a (C5a) generated by the complement alternative pathway during coagulation degrades endothelial barrier function. (a) Kinetic curves and (b) multiple comparisons at discrete time points of electric cell‐substrate impedance sensing (ECIS) assays. Human PMN were first incubated in 50% (v/v) plasma or serum without or with pretreatment of PMN with W‐54011 or diphenyleneiodium (DPI), then washed with cell culture medium, and subsequently placed in a Transwell filter over confluent human umbilical vein endothelial cell (HUVEC) monolayers grown on ECIS plates to measure endothelial barrier function. Vehicle control experiments without PMN shown in Figure S1. Results reported as mean ± standard error of the mean (s.e.m.). Significance was set at P ≤ 0·05. *P ≤ 0·05; **P ≤ 0·01; ***P ≤ 0·001; ****P ≤ 0·0001.