Soluble endothelial cell molecules and circulating endothelial cells in patients with venous thromboembolism
To evaluate the plasma levels of soluble endothelial cell molecules in patients with venous thromboembolism (VTE) out of the acute phase as compared with healthy individuals. We also investigated the possible associations of the soluble endothelial cell molecules among them, as well as with other clinical and laboratory data, including the numbers of circulating endothelial cells (CEC), circulating endothelial progenitor cells (CEP), and CEC expressing activation-related [cluster of differentiation (CD)54 and CD62E] and procoagulant (CD142) markers. In total, 15 patients with VTE and 20 normal individuals were studied. The CEC and CEP were quantified and characterized by flow cytometry. The soluble molecules studied included P-selectin, E-selectin, intercellular cell adhesion molecule 1, vascular cell adhesion molecule 1 and tissue factor (ELISA), and von Willebrand factor antigen (immunoturbidimetry). VTE patients had significantly higher levels of vascular cell adhesion molecule 1 and von Willebrand factor antigen and lower levels of soluble E-selectin than controls. They also showed significantly higher numbers of CEC, as of activated/procoagulant CEC and lower numbers of CEP, compared with controls. We did not find any correlation between the levels of soluble molecules and the numbers of endothelial cell in circulation, but there was with several clinical and laboratory data in VTE patients. Our results would suggest that in VTE patients, the endothelium remains activated and in some hypercoagulable state. The levels of soluble endothelial cell molecules did not seem to be directly related to the numbers of CEC and CEP neither reflected the number of activated CEC, which may be because of the different function that surface and soluble molecules may have.