Effect of polymyxin B and colimycin on induction of plasminogen antiactivator by lipopolysaccharide in human endothelial cell culture

Abstract

The effect of lipopolysaccharide (LPS) on the production of fibrinolytic inhibitor by human endothelial cells was determined because results of previous experiments have shown us that it is possible to stimulate this synthesis with muramyl dipeptide. Treatment of these cells with LPS resulted in a marked enhancement of fibrinolytic inhibitor, as estimated in a urokinase-induced fibrinolysis assay. A dose-response curve was obtained for LPS concentrations ranging from 10 to 1,000 ng/ml, thus demonstrating the great sensitivity of these cells. This inhibitor did not reduce plasmin activity and formed complexes with highand low-molecularweight urokinase as visualized by fibrin enzymography on sodium dodecyl sulfate-polyacrylamide electrophoretic gels. The molecular weight of this inhibitor was estimated to be 54 to 58 kilodaltons. These findings led us to conclude that LPS stimulates formation of a plasminogen antiactivator. This LPS effect could be suppressed by polymyxin B and colimycin. The stimulatory effect of muramyl dipeptide required doses which were at least 1,000 times greater than those of LPS and was not decreased by polymyxin B. These results show the possibility of independent modulation of plasminogen antiactivator production at the endothelial level, which could be important in endotoxemia. Under these conditions colimycin might have an additional advantage for clinical use because of its ability to prevent fibrinolytic inhibition.

Plasminogen Activator Inhibitor 1: A New Prognostic Marker in Septic Shock

“…It is not yet established whether this in vivo effect of endotoxin is direct or indirect via the induction of TNF and/or interleukin 1 (24). The latter two compounds, as well as endotoxin, stimulate PAI-1 release and downregulate t-PA release by endothelial cells (25)(26)(27)(28)(29)(30) and fibrosarcoma cells (31).…”

LPS-induced signals in activation of a caspase-3-like protease, a key enzyme regulating apoptotic cell damage into a macrophage-like cell line, J774.1, in the presence of cycloheximide

“…To understand the mechanisms underlying LPS-induced signals in the first 30 min, i.e., before the addition of CHX, we first examined the effects of polymyxin B, TPCK, genistein, herbimycin A, PD98059, SB202190, and SB203580 on the cytotoxicity induced by LPS and CHX. Polymyxin B [29] and TPCK [30] have been reported to inhibit LPS-induced signals, genistein and herbimycin A are inhibitors of tyrosine kinases [31,32], PD98059 is a MEK inhibitor [33], and SB202190 and SB203580 are MAP kinase inhibitors [34][35][36]. As shown in Figure 5a, the release of LDH induced by LPS and CHX was inhibited by the addition of polymyxin B, TPCK, genistein, or herbimycin A, but not by PD98059, SB202190, or SB203580 (Fig.…”

Pathophysiologic and Biochemical Events in Disseminated Intravascular Coagulation: Dysregulation of Procoagulant and Anticoagulant Pathways

“…It has been shown that the release of PAI is drastically increased after stimulation with endotoxin. 303 " 307 This inhibitor is active against t-PA as well as u-PA. 304,305 Dosne and colleagues 308 were the first to describe the production of a fibrinolytic inhibitor by cultured endothelial cells derived from human umbilical vein.…”