Circulating and placental endoglin concentrations in pregnancies complicated by intrauterine growth restriction and preeclampsia.

Inadequate trophoblast invasion and spiral artery remodeling leading to poor placental perfusion and hypoxia are believed to underlie preeclampsia (PE) and intrauterine growth restriction (IUGR). Recent studies implicate increased circulating endoglin as a contributor to the pathogenesis of PE. The objective of this study was to determine whether placental and circulating endoglin concentrations are altered in pregnancies complicated by intrauterine growth restricted (IUGR) infants and to address the role of hypoxia on the regulation of placental endoglin. We analyzed 10 placentas each from normal pregnant (NP), PE, and IUGR subjects. Endoglin levels were 2.5-fold higher in preeclamptic placentas compared to NP (15.4+/-2.6 versus 5.7+/-1.0, p<0.01). In contrast, endoglin levels were similar in NP and IUGR placentas (5.7+/-1.0 vs 5.9+/-1.1, p=NS). Placentas from pregnancies with both PE and IUGR exhibited endoglin levels comparable to the PE group and significantly different from normotensive pregnancies with and without IUGR pregnancies (mean 14.9+/-4.0, n=9, p=0.013). Soluble endoglin concentrations in maternal plasma were comparable in NP and IUGR, but higher in women with PE (n=10 per group, p<0.05). Despite a 2-fold increase in hypoxia inducible factor, HIF-1alpha, we did not observe endoglin upregulation in NP, PE, or IUGR placental villous explants exposed to hypoxia (2% oxygen). In contrast to PE, placental or circulating endoglin is not increased in normotensive women delivering small, asymmetrically grown (IUGR) infants at term. The placentas of women with IUGR appear to be fundamentally different from PE women with respect to endoglin, despite the proposed common pathology of deficient trophoblast invasion/spiral artery remodeling and poor placental perfusion.

OS098. Increased adiposity decreases the intensity myeloperoxidase in neutrophils from pregnant women at delivery.

INTRODUCTION: The cardiovascular risk factor myeloperoxidase (MPO) is a lysozomal enzyme found within azurophillic granules of inflammatory cells. Upon activation, inflammatory cells degranulate and release MPO. In the pregnancy disorder preeclampsia, MPO is elevated in the circulation and placenta and greater numbers of neutrophils are positive for hydrogen peroxide. OBJECTIVES: To determine if during preeclampsia, increases in circulating MPO result in losses of intracellular MPO within neutrophils. We also sought to determine if the degree by which neutrophil functionand intracellular MPO levels varies by BMI differsin women with preeclampsia compared to normal control pregnancies. METHODS: Reactive oxygen species (nitric oxide, superoxide and hydrogen preoxide) weredetermined in fresh whole blood samples from non-smoking women with normal pregnancies (n=8) and preeclampsia (n=9) by flow cytometry using intracellular fluorescent probes. Granulocytes were permeabilized (Dako, Glostrup, Denmark) and stained for MPO (anti-MPO, BD, San Jose, CA), and the number and percentage of CD15 and MPO positive cells and the intensity of MPO staining (MFI) was determined by flow cytometry. Student t-test or one-way ANOVA was used to test for significance. Dataare reported as mean±sem. RESULTS: There wasno significant difference in the number (percentage) orintensity of neutrophils staining for MPO between normal pregnancies and preeclampsia (MPO positive cells: 2816±981(39% positive) vs 2714±901(28% positive), Intensity: 3337±434 vs 3178±367 MFI units). However, there was a dramatic reduction in intensity of MPO staining in neutrophils from overweight women (BMI>27) compared to normal weight women regardless of pregnancy outcome (2508±160 vs 4091±376 MFI units, p=0.001). Among normal pregnancies, lean women had significantly more MFI of MPO than overweight women (4500±750 vs 2639±178 MFI units, p=0.04). The same trend was seen among women with preeclampsia (lean; 3845±428 vs overweight; 2344±292MFI units, p=0.07). CONCLUSION: The increased circulating levels of MPO in preeclampsia did not result in decreased intensity of MPO staining in circulating neutrophils. Neutrophils from normal weight women have greater amounts of intracellular MPO available upon activation than overweight and obese women. ACKNOWLEDGEMENT: This project was supported byNational Institutes of Health grant PO1-HD30367.