Maternal plasma concentrations of the placental specific sFLT-1 variant, sFLT-1 e15a, in fetal growth restriction and preeclampsia

Objective: sFLT-1 e15a is a recently described sFlt-1 variant that is placental and primate specific. As such, it may have potential as a biomarker. Using a newly developed ELISA, we measured maternal plasma sFLT-1 e15a levels in women with fetal growth restriction and pre-eclampsia. Method: We performed a nested case-control study where we measured total sFLT-1 and sFLT-1 e15a plasma protein concentrations. Samples, selected from a prospective cohort study, consisted of 87 healthy controls, 11 cases that developed term preeclampsia and 20 cases where there was fetal growth restriction. We also measured sFLT-1 and sFLT-1 e15a plasma concentrations in a separate cohort: 15 cases of preterm preeclampsia and 24 healthy controls. Results: The prospective case-control cohort demonstrated significantly increased sFLT-1 e15a among cases with term fetal growth restriction (p<0.05). We also observed that total sFLT-1 (this ELISA indiscriminately detects all variants) was significantly increased in term preeclampsia (p<0.0001), but not fetal growth restriction. The separate cohort of early-onset preeclamptics showed significantly increased sFLT-1 e15a levels (p<0.0001). Conclusion: Plasma sFLT-1 e15a is significantly increased in early-onset preeclampsia and term fetal growth restriction. Further assessment of the benefit for sFLT-1 e15a testing in prediction or diagnosis of these disease states is warranted.