Fetal growth restriction is characterized by changes in a biomarker of glycocalyx integrity

Placental insufficiency is a major cause of fetal growth restriction (FGR). The glycocalyx, a gel-like layer, covers the luminal surface of the endothelium and the intervillous space of the placenta, and it is crucial to maintain endothelial cell integrity and to prevent clotting. Syndecans are a major component of the glycocalyx. Syndecan-1 (SDC1) is a protoglycan produced by the syncytiotrophoblast that is capable of storing angiogenic factors and has important anticoagulant properties. This study was performed to determine whether FGR is associated with abnormalities in the glycocalyx, as reflected by SDC1 concentrations. A cross-sectional study was designed to include women with normal pregnancy (n=130) and pregnant women with FGR (n=50). Doppler velocimetry of the uterine (UT) and umbilical arteries (UA) was performed at the time of admission. Plasma concentrations of SDC1 were determined by a specific and sensitive immunoassay. 1) Patients with FGR had a lower mean plasma concentration of SDC1 than normal pregnant women [mean ± SD: 1465 ± 1295 ng/mL vs. 1857 ± 1223 ng/mL; P = 0.005]; 2) FGR with an abnormal UT Doppler (n=21, mean ± SD: 1315 ± 1476 ng/mL) had a lower mean plasma SDC1 concentration than normal pregnancy (P = 0.003); and 3) among patients with FGR, those with an abnormal UA Doppler had the lowest SDC1 level [n=10, mean + SD : 746 + 573 ng/mL; ANOVA p < 0.001], and there was an inverse relationship between the plasma SDC1 concentration and UA pulsatility index (r = −0.4; p = 0.01). The profile of SDC1 in FGR suggests that this condition is associated with abnormalities in the endothelial and syncytiotrophoblast glycocalyx. Non-invasive assessment of the glycocalyx with biophysical and biochemical methods during pregnancy may be useful in monitoring placental diseases.