Vascular endothelial growth factor and its receptor, Flt-1, in smokers and non-smokers

Raised levels of plasma vascular endothelial growth factor (VEGF) are found in some cancers, diabetes, and certain other conditions, but levels of its receptor, soluble Flt-1 (sFlt-1), in these diseases have yet to be reported. We hypothesised that smoking would influence levels of these molecules. Consequently, we measured VEGF and sFlt-1 by enzyme-linked immunosorbent assay (ELISA) in plasma from 92 non-smokers and 35 smokers. No difference in VEGF was seen between the groups but, despite considerable overlap, sFlt-1 was significantly lower in smokers (P = 0.027). VEGF and sFlt-1 correlated strongly with each other (P < 0.001). Although VEGF may arise from a number of cell types, including endothelial cells, the primary source of sFlt-1 is thought to be the endothelium; however, neither VEGF nor sFlt-1 correlated with levels of the endothelial cell activation/damage marker soluble thrombomodulin. Our data point to changes in levels of the VEGF receptor, sFlt-1--but not VEGF itself--in smokers, which appears to be unrelated to endothelial cell function.