Increased leukocyte adhesion to vascular endothelium in preeclampsia is inhibited by antioxidants

A comprehensive review of the roles of T-cell immunity in preeclampsia

Preeclampsia (PE) is an obstetrical disorder that occurs after the 20th week of gestation. It is recognized as one of the "Great Obstetrical Syndromes" and principally contributes to maternal morbidity and mortality. PE has been associated with a range of immune disorders, including a preponderance of T helper (Th) 1 over Th2 cells and imbalanced levels of Th17 and T regulatory cells (Tregs). During pregnancy, T cells safeguard the placenta against immune rejection and aid embryo implantation while involved in pregnancy complications, such as PE. Promoting alloantigen-specific Treg cells is a potential preventive and therapeutic strategy for PE. However, ensuring the safety of mothers and infants is of the utmost importance since the risk-benefit ratio of reproductive and obstetric conditions differs significantly from that of immune diseases that pose a life-threatening risk. In this review, we systematically summarize the roles of T-cell immunity in the peripheral blood, reproductive tissues, and at the maternal-fetal interface of PE patients. Furthermore, the recent therapeutic approaches centered on targeting T cell immunity in PE are critically appraised.

Association of Gestational Vitamin E Status With Pre-eclampsia: A Retrospective, Multicenter Cohort Study

Introduction

Pre-eclampsia is the second leading cause of maternal mortality worldwide. The controversy for the association of vitamin E with pre-eclampsia has raged unabated for two decades. We aimed to determine the association of vitamin E level in the first trimester and the gestational change with pre-eclampsia.

Materials and Methods

A retrospective cohort study was conducted among singleton pregnant women aged 15–49 years at 137 hospitals in China. Serum vitamin E concentrations in the first trimester and at pre-eclampsia assessment time were uniformly quantified in a laboratory by high performance liquid chromatography. Logistic regression models with restricted cubic splines were performed to reveal a non-linear association of vitamin E concentrations in the first trimester and the gestational change with pre-eclampsia.

Results

We included 73 317 participants (47.8% aged 25–29 years) and 2.28% were diagnosed with pre-eclampsia. Higher risk was observed in those with lower concentration in the first trimester and greater gestational decrease, with a range from 0.81 to 80.60%. A non-linear L-shaped association was observed between vitamin E concentrations in the first trimester and pre-eclampsia, suggesting a threshold at 7.3 mg/L and a ceiling effect: the risk saw a steep rise when the concentrations in the first trimester were < 7.3 mg/L but was relatively flat beyond the inflection point. Sharply increased pre-eclampsia risk was also found in those with gestational vitamin E decrease after accounting for the baseline status in the first trimester. However, gestational vitamin E increase was associated with decreased pre-eclampsia risk when the baseline concentrations were < 7.3 mg/L but did not confer additional benefits when it was above the threshold.

Conclusion

We demonstrated alarmingly high pre-eclampsia risk in women with vitamin E concentrations of < 7.3 mg/L in the first trimester and gestational vitamin E decrease. These findings underscore the need to supplement vitamin E among pregnant women with low baseline status.

Risk of preeclampsia by gestational weight gain in women with varied prepregnancy BMI: A retrospective cohort study

INTRODUCTION

Despite the important clinical significance, limited data on the joint contribution of prepregnancy body mass index (BMI) and gestational weight gain (GWG) to preeclampsia, the second leading cause of maternal mortality worldwide. This study aimed to estimate the risk of preeclampsia by GWG among women with varied prepregnancy BMI.

METHODS

We conducted a retrospective cohort study using data of 117 738 singleton pregnant women aged 18-49 years from 150 maternity hospitals in China between 2015 and 2018. GWG was calculated as the measured weight at the time of preeclampsia assessment minus prepregnancy weight; GWG velocity was calculated as the GWG divided by the gestational age at weighing. The non-linear associations of GWG with preeclampsia were examined by restricted cubic spline regression analysis according to prepregnancy BMI. The association of the GWG categories with preeclampsia was further examined by performing robust Poisson regression stratified by the prepregnancy BMI categories.

RESULTS

Among participants, 2426 (2.06%) were diagnosed with preeclampsia. Compared to women with normal BMI, those who were overweight and obese had 1.92- fold (95%CI, 1.73-2.14) and 5.06- fold (95%CI, 4.43-5.78) increased risks for preeclampsia, respectively. The association of GWG velocity with preeclampsia was presented as a J-shaped curve with the varied inflexion point (where the rate of preeclampsia was 2%), which was 0.54, 0.38, and 0.25 kg/week in women with normal BMI, overweight, and obesity, respectively; a steep risk rise was observed along with GWG velocity beyond the inflexion points. The overall adjusted relative risk for preeclampsia was calculated among women with the different GWG categories of GWG.

CONCLUSIONS

The findings highlight that high prepregnancy BMI and exceed GWG contributed to increased risk of preeclampsia with a superimposed effect and underscore the need to optimize the recommendations for GWG for women with different prepregnancy BMI.

Whole-Genome Uterine Artery Transcriptome Profiling and Alternative Splicing Analysis in Rat Pregnancy

During pregnancy, the uterine artery (UA) undergoes extensive remodeling to permit a 20–40 fold increase in blood flow with associated changes in the expression of a multitude of genes. This study used next-gen RNA sequencing technology to identify pathways and genes potentially involved in arterial adaptations in pregnant rat UA (gestation day 20) compared with non-pregnant rat UA (diestrus). A total of 2245 genes were differentially expressed, with 1257 up-regulated and 970 down-regulated in pregnant UA. Gene clustering analysis revealed a unique cluster of suppressed genes implicated in calcium signaling pathway and vascular smooth muscle contraction in pregnant UA. Transcription factor binding site motif scanning identified C2H2 ZF, AP-2 and CxxC as likely factors functional on the promoters of down-regulated genes involved in calcium signaling and vascular smooth muscle contraction. In addition, 1686 genes exhibited alternative splicing that were mainly implicated in microtubule organization and smooth muscle contraction. Cross-comparison analysis identified novel genes that were both differentially expressed and alternatively spliced; these were involved in leukocyte and B cell biology and lipid metabolism. In conclusion, this first comprehensive study provides a valuable resource for understanding the molecular mechanism underlying gestational uterine arterial adaptations during pregnancy.

Effects of glycol-split low molecular weight heparin on placental, endothelial, and anti-inflammatory pathways relevant to preeclampsia

Low molecular weight heparin (LMWH) is being investigated as a potential preventative therapy against preeclampsia. There is evidence suggesting that LMWH may prevent preeclampsia through anticoagulation-independent mechanisms. In this study, we compared the in vitro placental, endothelial, and anti-inflammatory effects of an LMWH (dalteparin) with a nonanticoagulant, glycol-split heparin derivative (gsHep). In contrast with dalteparin, gsHep did not interact with antithrombin III, possess significant anti-Factor Xa activity, or significantly prolong in vitro plasma clotting time. However, dalteparin and gsHep were otherwise mechanistically similar, both interacting with soluble fms-like tyrosine kinase-1 (sFlt1) and promoting release of the pro-angiogenic protein placental growth factor, but not the antiangiogenic sFlt1, from healthy placental villous explants. Placental explant media pretreated with dalteparin or gsHep significantly stimulated endothelial cell tube formation compared to untreated explants. Lastly, dalteparin and gsHep both significantly suppressed inflammation by inhibiting complement activation and leukocyte adhesion to endothelial cells that were activated using serum from preeclamptic women. Our data suggest that nonanticoagulant heparin derivatives may be utilized as a tool to distinguish the anticoagulation-independent mechanisms of LMWH, and provide insight into the role of anticoagulation in the prevention of preeclampsia.

Molecular actions of heparin and their implications in preventing pre-eclampsia

Pre-eclampsia, a hypertensive disorder of pregnancy, continues to be a significant cause of global maternal morbidity. Low-dose aspirin remains the only standard-of-care prophylactic therapy for preventing pre-eclampsia, but is limited in efficacy. Heparin and its derivatives may further enhance the efficacy of aspirin therapy to prevent pre-eclampsia, but the mechanisms mediating this augmentative effect are not known. Although heparin is an anticoagulant agent, it also possesses many anticoagulant-independent properties that may be relevant in the prevention of pre-eclampsia, including effects on placental, vascular and inflammatory function. This review summarizes the non-anticoagulant properties of heparin, and extrapolates how these actions may influence the trajectory of pre-eclampsia pathogenesis as a means of pathway-specific therapy.

Aberrant glycosylation of plasma proteins in severe preeclampsia promotes monocyte adhesion

Glycosylation of plasma proteins increases during pregnancy. Our objectives were to investigate an anti-inflammatory role of these proteins in normal pregnancies and determine whether aberrant protein glycosylation promotes monocyte adhesion in preeclampsia. Plasma was prospectively collected from nonpregnant controls and nulliparous patients in all 3 trimesters. Patients were divided into cohorts based on the applicable postpartum diagnosis. U937 monocytes were preconditioned with enzymatically deglycosylated plasma, and monocyte adhesion to endothelial cell monolayers was quantified by spectrophotometry. Plasma from nonpregnant controls, first trimester normotensives, and first trimester patients with mild preeclampsia inhibited monocyte-endothelial cell adhesion (P < .05), but plasma from first trimester patients with severe preeclampsia and second and third trimester normotensives did not. Deglycosylating plasma proteins significantly increased adhesion in all the cohorts. These results support a role of plasma glycoprotein interaction in monocyte-endothelial cell adhesion and could suggest a novel therapeutic target for severe preeclampsia.

Elevated maternal soluble Gp130 and IL-6 levels and reduced Gp130 and SOCS-3 expressions in women complicated with preeclampsia

Increased inflammatory response plays a significant role in the vascular pathophysiology in preeclampsia. However, the mechanism for increased inflammatory response in preeclampsia is largely unknown. Interleukin (IL)-6 levels are elevated in women with preeclampsia. IL-6 and its receptors, IL-6R and glycoprotein (gp)130, play a critical role in mediating antiinflammatory response via induction of SOCS-3 (suppressor of cytokine signaling-3). However, IL-6 receptor levels and expressions have not been studied in preeclampsia. In this study, we measured IL-6 and its 2 soluble receptors, soluble IL-6R and soluble gp130, in maternal plasma from normal and preeclamptic pregnant women and found that not only IL-6 but also soluble gp130 levels were significantly higher in preeclamptic women than in normotensive pregnant controls. We further examined IL-6R, gp130, and SOCS-3 expressions in maternal vessels and leukocytes and found that gp130 and SOCS-3 expressions were downregulated in both vessel endothelium and leukocytes from preeclampsia. Different patterns for IL-6R and gp130 expressions were found. IL-6R expression was also downregulated in leukocytes from preeclampsia. Our results suggest that increased plasma soluble gp130/soluble IL-6R/IL-6 ratio and reduced membrane transsignaling gp130 expression could contribute to decreased SOCS-3 expression and subsequent reduction in SOCS-3 antiinflammatory activity in women with preeclampsia. Thus, reduced gp130 and SOCS-3 expressions may offer, at least in part, a plausible explanation of reduced antiinflammatory protection in the maternal vascular system in preeclampsia.

Inhibition of VEGF or TGF-{beta} signaling activates endothelium and increases leukocyte rolling

OBJECTIVE

Motivated by the central roles that vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-beta play in the assembly and maintenance of the vasculature, we examined the impact of systemic VEGF or TGF-beta signal inhibition on endothelial activation as detected by leukocyte-endothelial interactions.

METHODS AND RESULTS

VEGF or TGF-beta inhibition, accomplished using adenovirus expression of soluble Flt1 (Ad-sFlt1) or soluble endoglin (Ad-sEng), resulted in a significant increase in the number of leukocytes rolling along the mesenteric venous endothelium and a significant decrease in rolling velocity in Ad-sEng mice. Neutralization of VEGF or TGF-beta resulted in endothelial surface expression of P-selectin and impaired peripheral vasodilatation. Neither inhibition of VEGF nor TGF-beta was associated with platelet or leukocyte activation, as detected by the activation markers platelet P-selectin and the active integrin alphaIIbbetaIII, or by leukocyte expression of L-selectin. Soluble vascular cell adhesion molecule (VCAM)-1 and E-selectin were increased in sEng-expressing mice, indicating higher levels of these adhesion receptors.

CONCLUSIONS

VEGF or TGF-beta neutralization leads to impaired endothelium-mediated vasodilatation and elevated expression of surface adhesion molecules, resulting in increased leukocyte adhesion. These results indicate an essential role for both VEGF and TGF-beta in maintaining the endothelium in a nonactivated state and have implications for therapeutic approaches that neutralize VEGF or TGF-beta.

Redox modulation of Ca2+ signaling in human endothelial and smooth muscle cells in pre-eclampsia

Pre-eclampsia (PE) is a leading cause of maternal hypertension in pregnancy and is associated with fetal growth restriction, premature birth, and fetal and maternal mortality. Activation and dysfunction of the maternal and fetal endothelium in PE appears to be a consequence of increased oxidative stress, resulting from elevated levels of circulating lipid peroxides. Accumulating evidence implicates reactive oxygen species (ROS) in the pathogenesis of vascular dysfunction in PE, perhaps involving a disturbance in intracellular Ca(2+) signaling. Several ion-transport pathways are highly sensitive to oxidative stress, and the resulting modulation of ion transport by ROS will affect intracellular Ca(2+) homeostasis. We review the evidence that changes in ion transport induced by ROS may be linked with abnormalities in Ca(2+)-mediated signal transduction, leading to endothelial and smooth muscle dysfunction in maternal and fetal circulations in PE. As dysregulation of Ca(2+) signaling in fetal umbilical endothelial cells is maintained in culture and embryonic, fetal, and postnatal development is affected by the cellular redox state, we hypothesize that impaired redox signaling in PE may influence "programming" of the fetal cardiovascular system and endothelial function in adulthood.