Circulating concentrations of sFlt1 (soluble fins-like tyrosine kinase 1) in fetal and maternal serum during pre-eclampsia

Objective: We hypothesized that umbilical vein serum soluble fms-like tyrosine kinase 1 (sFlt1) concentration was augmented in pre-eclampsia. We also explored a possible association between fetal and maternal concentrations of sFlt1. Study design: At cesarean delivery, maternal serum samples from pre-eclamptic (n = 38) and uncomplicated (n = 32) pregnancies were obtained, as well as umbilical vein serum and amniotic fluid samples. ELISA for human sFlt1, vascular endothelial growth factor (VEGF) and placental growth factor (PIGF) were performed. Results: Median sFlt1 concentrations were elevated in pre-eclampsia compared to uncomplicated pregnancy, in umbilical venous serum (246 and 163 pg/mL, P = 0.04), in maternal serum (9932 and 3417 pg/mL, P < 0.001), as well as in amniotic fluid (51,040 and 33,490 pg/mL, P = 0.03). A positive association between the fetal and maternal serum levels of sFlt1 was found in the pre-eclampsia group. Median PIGF concentration in the maternal serum was significantly lower in the pre-eclampsia group compared to the control group (82 pg/mL and 169 pg/ mL, P < 0.001). Conclusions: sFlt1 concentration is elevated in the fetal circulation in pre-eclampsia, but at a much lower level than in the maternal circulation. The results of our study do not support a substantial fetal contribution to the elevated circulating maternal sFlt1 protein concentration in pre-eclampsia. (c) 2004 Elsevier Ireland Ltd. All rights reserved.