Smoking and sVEGFR-1: Circulating maternal concentrations and placental expression

Smoking reduces the expression of VEGFR-1 in non-pregnant women. In pregnant women it reduces the risk of pre-eclampsia, which in turn is associated with increased placental expression of VEGFR-1 and increased maternal circulating soluble VEGFR-1 (sVEGFR-1). We therefore hypothesized that smoking might affect VEGFR-1 expression in pregnant women. In maternal plasma sVEGFR-1 concentrations during the third trimester in both smoking (median 1088, range 834–1362 ng/L, n = 20) and non-smoking (728, 719–1336 ng/L, n = 19) women were higher than during the second trimester (smokers 374, 291–683 ng/L, n = 6, p > 0.05; non-smokers 375, 290–667 ng/L, n = 22, p < 0.001). No difference was observed between smokers and non-smokers. Secretion of sVEGFR-1 into the culture medium, as well as the pattern and intensity of immunostaining in first trimester placenta were similar in tissue from smoking (n = 22) and non-smoking (n = 20) women. Thus, contrary to our hypothesis, smoking does not affect circulating maternal sVEGFR-1 concentrations or placental secretion of sVEGFR-1 or expression of VEGFR-1 in vitro.