Reduced circulating NrCAM as a biomarker for fetal growth restriction.

BACKGROUND: Placental insufficiency underpins pregnancy complications, fetal growth restriction (FGR) and preeclampsia, yet predictive biomarkers are limited. Neuronal Cell Adhesion Molecule (NrCAM) may be a promising biomarker of placental dysfunction. This study investigated whether NrCAM can predict diseases of placental insufficiency. METHODS: Circulating NrCAM was measured across independent cohorts. Plasma NrCAM was assessed at 36 weeks' gestation in women who later delivered FGR infants (<3rd centile birthweight), or developed preeclampsia at term. Circulating NrCAM was also measured in international cohorts: a UK high-risk cohort of women presenting with reduced fetal movements and delivered an FGR infant; a high-risk cohort from South Africa diagnosed with preeclampsia or eclampsia. NrCAM was also assessed in pregnancies with preterm FGR or preeclampsia (<34 weeks gestation). The effect of hypoxia on NrCAM expression was measured in trophoblast stem cells, primary trophoblasts, and a murine FGR model. FINDINGS: Circulating NrCAM was reduced at 36 weeks' gestation in women who later delivered FGR infants (p = 4.75 x 10(-6), AUC = 0.76, n = 26 FGR, n = 957 controls). In the UK cohort, reduced NrCAM levels were associated with FGR (p = 9.34 × 10(-3), AUC = 0.72, n = 12 FGR, n = 235 control). In the South Africa cohort, circulating NrCAM was reduced with preeclampsia (p = 0.03, AUC = 0.70, n = 27 preeclampsia, n = 15 control). Placental NrCAM expression was lower in FGR (p = 0.0003, n = 23 FGR) and preeclampsia (p = 0.0003, n = 41 preeclampsia, n = 20 controls). Hypoxia reduced NrCAM expression in human trophoblast stem cells (p < 0.01) primary trophoblasts (p < 0.0001) and in a murine FGR model (p < 0.01, n = 9 per group). INTERPRETATION: Reductions in plasma and placental NrCAM are strongly associated with FGR and may be driven by hypoxia. FUNDING: This study was funded by a grant from National Health and Medical Research Council.