Nuclear textural changes preceding endotoxin mediated enhancement of thromboplastin synthesis in human endothelial...

Human vascular endothelium plays a major role in hemostatic processes. Human venous endothelial cells (HEC) may promote coagulation by generation of thromboplastin. This tissue factor production is enhanced by bacterial lipopolysaccharide (LPS). However, the mechanisms of this enhancement remain unclear. In order to quantify by image analysis the nuclear modifications induced by LPS on HEC, umbilical cord vein HEC were cultured in vitro with or without E. coli LPS (10 micrograms/ml) for 0 to 6 h. At the end of culture, tissue factor expression was evaluated by the ability of a cellular extract to shorten the coagulation time of human citrated plasma. Simultaneously, the morphology of LPS treated and control HEC was analysed using a SAMBA 200 cell image processor after Feulgen staining. This analysis indicates that LPS treatment induces nuclear modifications as early as 1 h after culture onset, before any tissue factor expression. This activity appears only between 2 and 4 h of culture with LPS. Our data show that image analysis permits the detection of very early nuclear events in HEC and that these events precede the expression of functional properties which may be implicated in thrombotic processes.