Thrombin stimulates the adherence of neutrophils to human endothelial cells in vitro.

Abstract

Highly purified human thrombin stimulates the adherence of polymorphonuclear leukocytes (PMNs) to vascular endothelial cells (EC). When Indium-labeled PMNs were incubated with primary monolayers of cultured human umbilical vein EC, the basal adherence was 10±1% of the PMNs at 5 min. Addition of thrombin (2 U/ml) increased the mean adherence to 42±15%. Enhanced neutrophil adherence in response to thrombin was confirmed by experiments with unlabeled leukocytes, examined by phase contrast and scanning electron microscopy. The action of thrombin was on the EC, since it did not directly stimulate PMN adhesiveness when measured by aggregation or by adherence to nylon fiber columns. Furthermore, enhanced neutrophil adherence occurred when endothelial monolayers were treated with thrombin and washed before adding "'Indium ("'In)-labeled PMNs. Thrombin that had been inactivated with antithrombin III and heparin did not enhance neutrophil adherence. Prothrombin, Factor Xa, and fibrinogen were also ineffective. The stimulated adherence of PMNs was maximal 5 min after incubation of the EC with thrombin, and decreased thereafter. The response was dose-dependent, with half-maximal stimulation at 0.2-0.25 U thrombin/ml. The enhanced PMN adherence caused by thrombin may result in part from the production of platelet-activating factor (PAF) by the stimulated EC since (a) thrombin-stimulated EC synthesize PAF with a time course and concentration dependence that are similar to the time and concentration relationships for thrombin-stimulated PMN adherence, (b) PAF itself promoted neutrophil adherence to the EC monolayers, and (c) pretreatment of PMNs with PAF decreased the adherence stimulated by thrombin and PAF, but not adherence stimulated by N-formylmethionyl-leucyl-phenylalanine and C5a fragments, which indicates specific desensitization of PAF-mediated adherence.These studies demonstrate the endothelial cell-dependent stimulation of PMN adherence by thrombin, a novel mechanism of enhanced leukocyte adherence that may be important in interactions between the coagulation and inflammatory systems.

Short exposure of intestinal epithelial cells to TNF-α and histamine induces Mac-1-mediated neutrophil adhesion independent of protein synthesis

“…It is interesting that when HT29 cells were pretreated with histamine for 30 min, neutrophil adhesion was increased to the levels of TNF-␣ stimulation (5 h and 30 min). Thrombin, which had been shown to increase neutrophil adhesion to endothelial cells [36], did not affect neutrophil adhesion to HT29 cells.…”

Treatment of corticosteroid‐resistant ulcerative colitis with heparin —a report of 16 cases

“…23 Colonic mucosal capillary thrombi are found in ulcerative colitis 24 and thrombin itself stimulates leucocyte adhesion to endothelial cells. 25 Moreover inherited disorders of coagulation appear to protect against ulcerative colitis. 26 This study demonstrates a promising response to standard heparin in patients with ulcerative colitis resistant to conventional treatment.…”

Oncostatin M is a proinflammatory mediator. In vivo effects correlate with endothelial cell expression of inflammatory cytokines and adhesion molecules.

“…Human umbilical vein endothelial cells (HUVEC) were cultured in 24-mm multiwell plates or 24-mm transwell membranes (Costar Data Packaging Corp., Cambridge, MA) as described (20). Only monolayers of primary cultures that were tightly confluent (24 h postconfluence) were used for these studies.…”

“…Only monolayers of primary cultures that were tightly confluent (24 h postconfluence) were used for these studies. Neutrophils were isolated from human blood and labeled with 111 In-oxine as before (20). Endothelial cell and blood procurement was approved by the University of Utah's Institutional Review Board.…”