Thrombin generation in plasma with adherent (A) or suspended cells (B). Apoptosis in adherent and suspended HUVECs was induced by treatment with staurosporine for 2 hours (A; solid triangles) and by culture in suspension with serum deprivation for 16 hours (B; shaded triangles), respectively. Cells were then incubated with 0.5 mL of citrated platelet-rich (adherent cells) and platelet-poor plasma (suspended cells). After starting the coagulation process with 0.5 mL of prewarmed CaCl₂ , the formation of thrombin was monitored using a chromogenic substrate. Controls were untreated cells (A and B; ○). As negative controls (A and B; □), subendothelial matrix and no cells were used, respectively. Results are expressed as mean ± SD (n = 6).