The prediction of early preeclampsia: Results from a longitudinal proteomics study

Abstract

Objectives: To identify maternal plasma protein markers for early preeclampsia (delivery <34 weeks of gestation) and to determine whether the prediction performance is affected by disease severity and presence of placental lesions consistent with maternal vascular malperfusion (MVM) among cases.

Study design: This longitudinal case-control study included 90 patients with a normal pregnancy and 33 patients with early preeclampsia. Two to six maternal plasma samples were collected throughout gestation from each woman. The abundance of 1,125 proteins was measured using high-affinity aptamer-based proteomic assays, and data were modeled using linear mixed-effects models. After data transformation into multiples of the mean values for gestational age, parsimonious linear discriminant analysis risk models were fit for each gestational-age interval (8-16, 16.1-22, 22.1-28, 28.1-32 weeks). Proteomic profiles of early preeclampsia cases were also compared to those of a combined set of controls and late preeclampsia cases (n = 76) reported previously. Prediction performance was estimated via bootstrap.

Results: We found that 1) multi-protein models at 16.1-22 weeks of gestation predicted early preeclampsia with a sensitivity of 71% at a false-positive rate (FPR) of 10%. High abundance of matrix metalloproteinase-7 and glycoprotein IIbIIIa complex were the most reliable predictors at this gestational age; 2) at 22.1-28 weeks of gestation, lower abundance of placental growth factor (PlGF) and vascular endothelial growth factor A, isoform 121 (VEGF-121), as well as elevated sialic acid binding immunoglobulin-like lectin 6 (siglec-6) and activin-A, were the best predictors of the subsequent development of early preeclampsia (81% sensitivity, FPR = 10%); 3) at 28.1-32 weeks of gestation, the sensitivity of multi-protein models was 85% (FPR = 10%) with the best predictors being activated leukocyte cell adhesion molecule, siglec-6, and VEGF-121; 4) the increase in siglec-6, activin-A, and VEGF-121 at 22.1-28 weeks of gestation differentiated women who subsequently developed early preeclampsia from those who had a normal pregnancy or developed late preeclampsia (sensitivity 77%, FPR = 10%); 5) the sensitivity of risk models was higher for early preeclampsia with placental MVM lesions than for the entire early preeclampsia group (90% versus 71% at 16.1-22 weeks; 87% versus 81% at 22.1-28 weeks; and 90% versus 85% at 28.1-32 weeks, all FPR = 10%); and 6) the sensitivity of prediction models was higher for severe early preeclampsia than for the entire early preeclampsia group (84% versus 71% at 16.1-22 weeks).

Conclusion: We have presented herein a catalogue of proteome changes in maternal plasma proteome that precede the diagnosis of preeclampsia and can distinguish among early and late phenotypes. The sensitivity of maternal plasma protein models for early preeclampsia is higher in women with underlying vascular placental disease and in those with a severe phenotype.

Fig 1. Sensitivity for early preeclampsia using multi-protein markers.

Sensitivity (y-axis) at a 10% FPR are shown by gestational-age interval (x-axis) for early preeclampsia (PE), early PE with placental lesions consistent with MVM, and severe early PE. The vertical bars represent the average (with 95% confidence intervals) of sensitivity obtained from 200 bootstrap iterations. Early PE: early preeclampsia; FPR: false-positive rate; MVM: maternal vascular malperfusion.

Fig 2. Longitudinal maternal plasma abundance of MMP-7 and gpIIbIIIA in normal pregnancy and early preeclampsia.

Each line corresponds to a single patient (grey = normal pregnancy, red = early preeclampsia). Individual dots represent samples at 8–16 weeks (A, B) and 16.1–22 weeks (C, D) of gestation. Samples taken at the time of diagnosis with early preeclampsia are marked with an “x” and were not included in the analysis but only displayed. The thick black line represents the mean value in normal pregnancy. AUC: area under the receiver operating characteristic curve of the protein using data in the current interval; early PE: early preeclampsia; FC: fold change; gpIIbIIIa: glycoprotein IIb/IIIa; MMP-7: matrix metalloproteinase 7; MoM: multiples of the mean; p: the nominal significance p-value comparing mean MoM values between groups with a moderated t-test. Log₂FC is the log (base 2) of the fold change between the cases and control groups, with negative values denoting lower MoM values in cases than in controls.

Fig 3

Longitudinal maternal plasma abundance of siglec−6 (A), PlGF (B), VEGF121 (C), and activin-A (D) in normal pregnancy and early preeclampsia cases, highlighting differences at 22.1–28 weeks. AUC: area under the receiver operating characteristic curve; early PE: early preeclampsia; FC: fold change; PlGF: placental growth factor; Siglec-6: sialic acid binding immunoglobulin-like lectin; VEGF121: vascular endothelial growth factor A, isoform 121.

Fig 4. Longitudinal maternal plasma ALCAM abundance in normal pregnancy and early preeclampsia cases, highlighting differences at 28.1–32 weeks.

ALCAM: activated leukocyte cell adhesion molecule; AUC: area under the receiver operating characteristic curve; early PE: early preeclampsia; FC: fold change; MVM: maternal vascular malperfusion.

Fig 5. Longitudinal maternal plasma ACE2 abundance in normal pregnancy and early preeclampsia cases, highlighting differences at 8–16 weeks of gestation.

See Fig 2 legend for more details. ACE2: angiotensin-converting enzyme 2; AUC: area under the receiver operating characteristic curve; early PE: early preeclampsia; FC: fold change; MVM: maternal vascular malperfusion.

Fig 6

Longitudinal maternal plasma abundance of siglec-6 (A) and activin-A (B) in normal pregnancy and early preeclampsia, highlighting differences at 22.1–28 weeks. Blue dots correspond to samples taken from late preeclampsia cases. AUC: area under the receiver operating characteristic curve; early PE: early preeclampsia; FC: fold change; late PE: late preeclampsia; Siglec-6: sialic acid binding immunoglobulin-like lectin.

Fig 7. A summary of differential protein abundance between early preeclampsia and normal pregnancy throughout gestation.

The values shown using a color scheme represent the log₂ fold change in MoM values between the cases and controls (green = lower, red = higher mean MoM in cases versus controls). Fold changes >1.5 (absolute log₂ fold change >0.58) were reset to 1.5 to enhance visualization of the data.