Altered sensitivity to a novel vasoconstrictor endothelin-1 (1-31) in myometrium and umbilical artery of women with severe preeclampsia

Sex-specific differences in hypertension and associated cardiovascular disease

Although intrinsic mechanisms that regulate arterial blood pressure (BP) are similar in men and women, marked variations exist at the molecular, cellular and tissue levels. These physiological disparities between the sexes likely contribute to differences in disease onset, susceptibility, prevalence and treatment responses. Key systems that are important in the development of hypertension and cardiovascular disease (CVD), including the sympathetic nervous system, the renin-angiotensin-aldosterone system and the immune system, are differentially activated in males and females. Biological age also contributes to sexual dimorphism, as premenopausal women experience a higher degree of cardioprotection than men of similar age. Furthermore, sex hormones such as oestrogen and testosterone as well as sex chromosome complement likely contribute to sex differences in BP and CVD. At the cellular level, differences in cell senescence pathways may contribute to increased longevity in women and may also limit organ damage caused by hypertension. In addition, many lifestyle and environmental factors - such as smoking, alcohol consumption and diet - may influence BP and CVD in a sex-specific manner. Evidence suggests that cardioprotection in women is lost under conditions of obesity and type 2 diabetes mellitus. Treatment strategies for hypertension and CVD that are tailored according to sex could lead to improved outcomes for affected patients.

Maternal EDN1 G5665T polymorphism influences circulating endothelin-1 levels and plays a role in determination of preeclampsia phenotype

OBJECTIVE

Preeclampsia, a pregnancy-specific syndrome characterized by hypertension and proteinuria, has a familial tendency and is an important cause of maternal and neonatal mortality. Abnormal endothelin-1 synthesis and/or release can explain abnormalities seen in preeclampsia. We prospectively evaluated whether endothelin-1 levels are increased in preeclampsia, to verify if placenta is the source, and any association between the maternal EDN1 G5665T single-nucleotide polymorphism and circulating endothelin-1 levels and preeclampsia manifestation.

METHODS

A total of 120 with preeclampsia and 118 normotensive primigravid patients with singleton pregnancy were enrolled. Preeclampsia was defined as new onset of elevated blood pressure greater than 140/90 mmHg and at least 2+ proteinuria on two occasions at least 4 h apart after 20 weeks of gestation in previously normotensive pregnant women. Patients were excluded if they had hypertension before 20 weeks of gestation, diabetes, asthma, heart disease, kidney disease, hematological disorder, autoimmune disease, urinary tract infection, current or past history of smoking, twin pregnancy, molar pregnancy or eclampsia. Genotyping was done using a PCR-RFLP-based method. Placenta samples were collected from 20 preeclampsia and 24 normotensive pregnancies. Reverse transcriptase PCR was done for preproendothelin and beta-actin mRNA. Placental endothelin-1 staining was assessed by immunohistochemistry in villous and extravillous trophoblasts and endothelium. Plasma endothelin-1 levels were measured using ELISA.

RESULTS

The preeclampsia group showed higher circulating endothelin-1 levels (1.45 +/- 0.55 vs. 0.91 +/- 0.42 pg/ml; P < 0.0001), reduced frequency of GG genotype (34 vs. 49%; P = 0.025) and increased T allele frequency (0.43 vs. 0.28; P = 0.04). A significant association was noted between endothelin-1 levels and blood pressure in the entire cohort and in the group with preeclampsia (P < 0.001). Circulating endothelin-1 levels were higher in those bearing even one copy of the T variant (1.08 +/- 0.48 vs. 1.31 +/- 0.59 pg/ml; P = 0.004). Placental endothelin-1/beta-actin mRNA ratio was significantly reduced (0.91 +/- 0.77 vs. 3.20 +/- 1.68; P < 0.001) and endothelin-1 staining was lower (P < 0.001) in placental endothelium in preeclampsia.

CONCLUSION

Maternal endothelin-1 is elevated and correlates with the severity of blood pressure elevation in preeclampsia. The endothelin-1 is likely released from the maternal endothelium. Presence of T allele at 5665 position in maternal EDN1 gene is associated with higher endothelin-1 levels. Placental endothelin-1 synthesis is reduced in preeclampsia. The combination of elevated maternal and reduced placental endothelin-1 may be an adaptive response to reduced uteroplacental flow in preeclampsia.

Screening and analyzing the potential bioactive components from Shaofu Zhuyu decoction, using human umbilical vein endothelial cell extraction and high-performance liquid chromatography coupled with mass spectrometry

In this paper, a useful method for screening and analyzing the potential bioactive components in bioassay-guided fraction (SF-11) from Shaofu Zhuyu decoction was developed using human umbilical vein endothelial cell (HUVEC) extraction and high-performance liquid chromatography coupled with Q-TOF/MS spectrometry. In addition, the protective effects on HUVEC damage induced by adrenaline in vitro were also investigated. The results showed that SF-11 significantly inhibited the endothelin (ET) release and reversed the NO secretion of HUVEC (p < 0.05), and promoted the PGI(2) release of HUVEC (p < 0.05). Two effective components, paeoniflorin and typhaneoside, from SF-11 were screened and identified using live cell extract and HPLC coupled with Q-TOF/MS spectrometry. The compounds, paeoniflorin and typhaneoside, showed significantly inhibiting effects on the ET release and reversing of NO secretion of HUVEC (p < 0.05), with similar effects to SF-11, and promoting the PGI(2) release of HUVEC at the concentration of 0.208 and 0.013 micromol/mL, respectively (p < 0.05). These data indicated that the method of live cell extraction coupled with HPLC-MS technology is feasible, rapid and useful for screening and analyzing potential bioactive components from TCMs.

Abnormalities in intracellular Ca2+ regulation in fetal vascular smooth muscle in pre-eclampsia: enhanced sensitivity to arachidonic acid

Pre-eclampsia (PE) is a leading cause of maternal and fetal mortality and morbidity. As free fatty acid metabolism is abnormally regulated in PE, we investigated the intracellular Ca2+([Ca2+]i) response to arachidonic acid (AA) in primary cultures of human umbilical artery smooth muscle cells (HUASMC). AA (50 microM) caused a significantly greater [Ca2+]i elevation in PE than in normal HUASMC, with many cells displaying a delayed secondary increase. The nonmetabolizable AA analog ETYA did not induce a response, suggesting that the augmented PE response depends on an AA metabolite. Inhibition of the AA metabolizing cyclooxygenase or lipoxygenase pathways did not affect the AA response of PE HUASMC but induced in normal cells the secondary rise of [Ca2+]i observed in PE cells. This potentiated response and the response in PE cells were blocked by inhibitors of the monooxygenase pathway, a third AA metabolizing pathway. We conclude that the [Ca2+]i response of HUASMC is elevated in PE because of an increased level of a monooxygenase metabolite that stimulates Ca2+ influx and that this can be mimicked in normal cells by blocking cyclooxygenase or lipoxygenase to divert AA to the monooxygenase. This and our work with fetal endothelial cells (FASEB J. 10.1096/fj.01-0916fje) demonstrate phenotypic changes in the fetal vasculature in PE.

Endothelin-1 activity in pregnancy

Plasma endothelin-1 activity was measured by radioimmunoassay in 24 normotensive non-pregnant women and in 24 normotensive pregnant, 24-aproteinuric hypertensive and 24 pre-eclamptic women. Endothelin-1 activity was increased in the pre-eclamptic group (2.7 +/- 06 pg/ml) compared to the normotensive non-pregnant (1.0 +/- 0.8 pg/ml; P < 0.0001), normotensive pregnant (1.2 +/- 0.4 pg/ml; P < 0.0001) group and the aproteinuric hypertensive group (1.4 +/- 0.7 pg/ml; P < 0.0001). There was no difference in endothelin-1 activity between the normotensive non-pregnant and normotensive pregnant group (1.0 +/- 0.8 vs. 1.2 +/- 0.4 pg/ml; P = 0.3). However, there was a difference between the aproteinuric hypertensive group (1.4 +/- 0.7 pg/ml) and both the normotensive nonpregnant (1.0 +/- 0.8 pg/ml; P < 0.01) and the normotensive pregnant group (1.2 +/- 0.4 pg/ml; P < 0.06). The birth weight in the pre-eclamptic group (2.48 +/- 0.61 kg) was significantly lower than that of the normotensive pregnant group (2.85 +/- 0.33 kg; P < 0.001) and the aproteinuric hypertensive group (2.99 +/- 0.46 kg; P < 0.001). In addition, there was no difference in birth weight between the normotensive pregnant group and aproteinuric hypertensive group (2.85 +/- 0.33 vs. 2.99 +/- 0.46 kg; P = 0.3). A significant Pearson's correlation of plasma endothelin-l versus birth weight in the pre-eclamptic group was obtained (r = 0.64; P < 0.0001). Endothelin-1 activity is increased with pre-eclampsia in black African women with pre-eclampsia. The results of our study also suggests an ethnic difference in plasma endothelin-1 activity when compared to result of studies carried out in Caucasian women with hypertensive disorders of pregnancy.