Release of sVEGF and sVEGFR1 from White Blood Cells and Platelets During Surgery and Stimulation with Bacterial Antigens

Svendsen, M. N.; Werther, K.; Bisgaard, T.; Christensen, I. J.; Nielsen, H. J.

Introduction: The influence of surgery on release of soluble vascular endothelial growth factor (sVEGF) and the soluble vascular endothelial growth factor inhibitory receptor 1 (sVEGFR1) is unknown. We studied the effect of major and minor surgery on potential variations in sVEGF and sVEGFR1 concentrations in vivo and on bacterial antigen‐induced release of sVEGF and sVEGFR1 from whole blood in vitro. Methods: Sixty‐one patients with abdominal diseases undergoing five different surgical procedures were included. Blood samples were drawn from anaesthetized patients before and after the operation. White blood cells and platelets were counted, and plasma sVEGF and sVEGFR1 was determined by an ELISA method. Whole blood from each blood sample was stimulated in vitro with bacteria‐derived antigens (LPS or protein‐A) and sVEGF and sVEGFR1 levels were subsequently determined in the supernatants. Stimulation with isotonic saline served as control assay. Results: Neither sVEGF or sVEGFR1 in plasma changed during surgery. In vitro stimulation of blood samples with bacteria‐derived antigens resulted in a significant increase in sVEGF (P < 0.0001) and a less pronounced but still significant increase in sVEGFR1. Release of sVEGF due to stimulation was significantly higher after the operation (nonsignificant), whereas sVEGFR1 release remained largely unchanged after surgery. Correlation between bacterial antigen‐induced release of sVEGF and neutrophile cell count was highly significant (P < 0.0001). There was no correlation between sVEGF and platelet cell count, and bacterial antigen‐induced sVEGFR1 release did not correlate with counts of neutrophils and platelets. Conclusions: Plasma sVEGF and sVEGFR1 concentrations did not change during surgery. In vitro bacterial stimulation led to increased release of sVEGF and sVEGFR1, which was not significantly amplified during surgery and which may be related to number of circulating neutrophils.