Reduced cellular glutathione reductase activity and increased adhesion molecule expression in endothelial cells cultured with maternal plasma from women with preeclampsia.

Abstract

Objective: The purpose of the current study was to determine whether maternal circulating components could regulate oxidative status of glutathione redox cycle and adhesion molecule expression in endothelial cells (ECs).

Methods: Maternal plasma was extracted from venous blood obtained from normal term pregnant women and from women with preeclampsia (PE). Normal and PE pregnancies were defined as American College of Obstetricians and Gynecologists criteria. Confluent ECs were incubated with EC growth medium (EGM) containing 20% plasma from women with normal (n = 8) and PE (n = 8) pregnancies for 4 hours. ECs incubated with EGM only were used as control. EC oxidative status was assessed by measuring cellular glutathione reductase (GR) and glutathione peroxidase (GPx) activities. Adhesion molecule expressions for intercellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), P-selectin, and E-selectin were determined by colorimetric assays detected on EC surface by UV spectrophotometer at OD 450 nm. Data are presented as mean +/- SE and analyzed by analysis of variance (ANOVA). A P value < .05 was set as statistically significant.

Results: Cellular GR activity was reduced approximately 35% in ECs treated with normal plasma and 70% in ECs treated with PE plasma compared to that in untreated control cells: 0.072 +/- 0.014 (P < .05), 0.039 +/- 0.006 (P < .01), versus 0.117 +/- 0.010 U/mg cellular protein, respectively. In contrast, GPx activity was slightly increased in ECs treated with normal plasma and significantly increased in ECs treated with PE plasma compared to that in untreated control cells: 0.059 +/- 0.005, 0.075 +/- 0.012 (P < .05) versus 0.044 +/- 0.002 U/mg cellular protein, respectively. P-selectin, E-selectin, and VCAM expressions were elevated in cells treated with normal plasma but significantly increased in cells treated with PE plasma compared to those of untreated controls: P-selectin--0.18 +/- 0.03, 0.35 +/- 0.04 versus 0.04 +/- 0.01 OD 450 nm, P < .01; E--selectin-0.06 +/- 0.02, 0.10 +/- 0.02 (P < .05) versus 0.03 +/- 0.01 OD 450 nm; VCAM--0.12 +/- 0.02, 0.16 +/- 0.03 (P < .01) versus 0.08 +/- 0.02 OD 450 nm, respectively. There was no difference for ICAM expression in cells treated with normal or PE plasma compared to controls.

Conclusions: These data suggest that endothelial pro- and anti-oxidative status could be directly affected by circulating components during pregnancy. Reduced cellular GR activity and increased GPx activity accompany increased inflammatory reactions in ECs responding to circulating "toxic" factors in preeclampsia.