Increased Endothelial Monolayer Permeability is Induced by Serum from Women with Preeclampsia but not by Serum from Women with Normal Pregnancy or that are not Pregnant

Abstract

Objective. To determine if endothelial monolayer permeability could be altered by serum from preeclampsia (PE). Methods. Confluent normal endothelial cells (ECs) were incubated with 20% serum from nonpregnant females, normal and PE pregnancies or combined with antioxidant superoxide dismutase (SOD) for 8 hr. Confluent PE ECs were incubated with 20% serum from normal pregnancies. EC barrier function of monolayer permeability was accessed by measuring EC electrical resistance (ER) and the leakage of horseradish peroxidase (HRP) passing through EC filters. Plasma concentrations of IL‐8 and lipid peroxides by MDA were also measured. We determined 1) if serum from PE could affect EC permeable function; 2) if antioxidant and serum from normal pregnancies could preserve PE EC barrier function; 3) if lipid peroxides and cytokine IL‐8 were increased in PE blood samples. Data are presented as mean±SE. ANOVA was used for statistical analysis. A p level less than 0.05 was considered statistically different. Results. 1) ER was significantly decreased and HRP passage was significantly increased in ECs incubated with serum from PE compared to serum from non‐pregnant and normal pregnant females (ER: 36.30±2.60 vs. 51.30±4.00 and 53.90±5.80 Ω·cm2, p<0.01; HRP: 0.100±0.020 vs. 0.014±0.002 and 0.022±0.007 ΔOD470 nm, p<0.01, respectively). 2) ER was improved in PE ECs incubated with serum from normal pregnancies compared to controls, 52.28±3.13 vs. 34.50±3.80 Ω·cm2, p<0.01. 3) SOD attenuated decreased EC ER induced by PE serum, 55.58±3.61 Ω·cm2 (SOD+PE serum) vs. 42.34±3.24 (control) and 35.46±2.44 (PE serum), p<0.01, respectively. 4) Both MDA and IL‐8 concentrations were higher in plasma or serum samples from PE than those in samples from nonpregnancies and normal pregnancies, MDA: 28.65±1.45 vs. 22.40±1.47 and 25.53±0.89 μmol/mL, p<0.01; IL‐8: 5.35±1.08 vs. 1.69±0.47 and 2.28±0.73 pg/mL, p<0.05, respectively. Conclusions. 1) Sera from PE but not from nonpregnant women or normal pregnancies increase EC monolayer permeability. 2) Increased lipid peroxides and IL‐8 are candidates altering EC barrier function. 3) Antioxidant SOD preserves increased EC monolayer permeability induced by PE serum, suggesting that EC oxidative stress may be associated with altered EC barrier function in preeclampsia.