The Prognostic Role of Angiotensin II Type 1 Receptor Autoantibody in Non-Gravid Hypertension and Pre-eclampsia: A Meta-analysis and Our Studies

Vasoregulatory Autoantibodies and Clinical Outcome After Ischemic Stroke-PROSCIS-B

BACKGROUND

Vasoregulatory autoantibodies including autoantibodies targeting G-protein-coupled receptors might play a functional role in vascular diseases. We investigated the impact of vasoregulatory autoantibodies on clinical outcome after ischemic stroke.

METHODS AND RESULTS

Data were used from the PROSCIS-B (Prospective Cohort With Incident Stroke-Berlin). Autoantibody-targeting receptors such as angiotensin II type 1 receptor (AT1R), endothelin-1 type A receptor, complement factor-3 and -5 receptors, vascular endothelial growth factor receptor-1 and -2, vascular endothelial growth factor A and factor B were measured. We explored associations of high antibody levels with (1) poor functional outcome defined as modified Rankin Scale >2 or Barthel Index <60 at 1 year after stroke, (2) Barthel Index scores over time using general estimating equations, and (3) secondary vascular events (recurrent stroke, myocardial infarction) or death up to 3 years using Cox proportional hazard models. We included 491 patients with ischemic stroke with data on autoantibody levels and outcome. In models adjusted for demographics and vascular risk factors, high autoantibody concentrations (quartile 4) targeting complement factor C3a receptor, vascular endothelial growth factor receptor-2, and vascular endothelial growth factor B were associated with poor functional outcome at 1 year: (odds ratio, 2.0 [95% CI, 1.1-3.6]; odds ratio, 1.8 [95% CI, 1.1-3.2]; and odds ratio, 2.1 [95% CI, 1.2-3.6], respectively) and with lower Barthel Index scores over 3 years (complement factor C3a receptor: adjusted β=-3.3 [95% CI, -5.7 to -0.5]; VEGF-B: adjusted β=-2.4 [95% CI, -4.8 to -0.06]). Patients with high autoantibody levels were not at higher risk for secondary vascular events or death.

CONCLUSIONS

High levels of autoantibodies against vascular endothelial growth factor receptor-2, vascular endothelial growth factor B, and complement factor C3a receptor measured are associated with poor functional outcome after stroke but not with recurrent vascular events or death.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01363856.

Pre-eclampsia

Pre-eclampsia is a life-threatening disease of pregnancy unique to humans and a leading cause of maternal and neonatal morbidity and mortality. Women who survive pre-eclampsia have reduced life expectancy, with increased risks of stroke, cardiovascular disease and diabetes, while babies from a pre-eclamptic pregnancy have increased risks of preterm birth, perinatal death and neurodevelopmental disability and cardiovascular and metabolic disease later in life. Pre-eclampsia is a complex multisystem disease, diagnosed by sudden-onset hypertension (>20 weeks of gestation) and at least one other associated complication, including proteinuria, maternal organ dysfunction or uteroplacental dysfunction. Pre-eclampsia is found only when a placenta is or was recently present and is classified as preterm (delivery <37 weeks of gestation), term (delivery ≥37 weeks of gestation) and postpartum pre-eclampsia. The maternal syndrome of pre-eclampsia is driven by a dysfunctional placenta, which releases factors into maternal blood causing systemic inflammation and widespread maternal endothelial dysfunction. Available treatments target maternal hypertension and seizures, but the only 'cure' for pre-eclampsia is delivery of the dysfunctional placenta and baby, often prematurely. Despite decades of research, the aetiology of pre-eclampsia, particularly of term and postpartum pre-eclampsia, remains poorly defined. Significant advances have been made in the prediction and prevention of preterm pre-eclampsia, which is predicted in early pregnancy through combined screening and is prevented with daily low-dose aspirin, starting before 16 weeks of gestation. By contrast, the prediction of term and postpartum pre-eclampsia is limited and there are no preventive treatments. Future research must investigate the pathogenesis of pre-eclampsia, in particular of term and postpartum pre-eclampsia, and evaluate new prognostic tests and treatments in adequately powered clinical trials.

Endocytosis and signaling of angiotensin II type 1 receptor

A vasoactive octapeptide angiotensin II (Ang II) hormone is the key regulator of the renin-angiotensin system (RAS). It binds with the two different plasma membrane receptors like angiotensin II type 1 (AT1) and type 2 (AT2) and consequence various biological responses occur. Further, AT1 has two subtypes such as AT1A and AT1B. These angiotensin receptors are classified to be G protein-coupled receptors (GPCRs). The main constituent of RAS is the AT1 receptor (AT1R), and its activation, signal transduction, and regulation have been extensively studied. After Ang II stimulation, the ligand-receptor complexes internalized and trafficked through the early endosome, recycling endosome, and some receptors skipped the recycling endosome and trafficked to the lysosome for metabolic degradation. Moreover, some short sequence motifs located in the carboxyl-terminus (CT) of the receptor play a vital role in the internalization, phosphorylation, subcellular trafficking, signaling, and desensitization. Furthermore, in endocytosis, the various proteins interact with the CT region of the receptor. This chapter highlights the basic mechanism of AT1 receptor internalization, trafficking and signaling in both physiological and pathophysiological conditions.

PUM1 modulates trophoblast cell proliferation and migration through LRP6

Preeclampsia is a severe pregnancy complication characterized by hypertension and may cause maternal morbidity and mortality. A better understanding of the essential genes involved in preeclampsia pathophysiology is urgently needed. This study investigated the function and molecular mechanisms of pumilio RNA binding family member 1 (PUM1) in extravillous trophoblast cells (EVTs). The interaction between protein and mRNA was verified by RNA pull-down assays, RNA immunoprecipitation assays, and luciferase reporter assays. The mRNA and protein levels of the genes involved were determined by RT-qPCR and western blot assays, respectively. Our results demonstrated that PUM1 could bind to the 3'-untranslated region of low-density lipoprotein receptor-related protein 6 (LRP6) mRNA, resulting in reduced expression of LRP6 mRNA and protein. Repression of PUM1 resulted in enhanced colony formation, cell proliferation, migration, and invasion of EVTs. The PUM1-depletion-mediated promotion effects on EVTs could be abrogated by LRP6 knockdown. PUM1 regulates the growth and mobility of EVTs by modulating LRP6 expression. Developing strategies to balance PUM1 and LRP6 levels may be beneficial for the management of preeclampsia patients.

Increased AT2R expression is induced by AT1R autoantibody via two axes, Klf-5/IRF-1 and circErbB4/miR-29a-5p, to promote VSMC migration

Vascular remodeling can be caused by angiotensin II type 1 receptor (AT₁R) autoantibody (AT1-AA), although the related mechanism remains unknown. Angiotensin II type 2 receptor (AT₂R) plays multiple roles in vascular remodeling through cross-talk with AT₁R in the cytoplasm. Here, we aimed to explore the role and mechanism of AT₂R in AT1-AA-induced vascular smooth muscle cell (VSMC) migration, which is a key event in vascular remodeling. In vitro and in vivo, we found that AT₂R can promote VSMC migration in AT1-AA-induced vascular remodeling. Moreover, AT₂R expression was upregulated via Klf-5/IRF-1-mediated transcriptional and circErbB4/miR-29a-5p-mediated posttranscriptional mechanisms in response to AT1-AA. Our data provide a molecular basis for AT1-AA-induced AT₂R expression by transcription factors, namely, a circular RNA and a microRNA, and showed that AT₂R participated in AT1-AA-induced VSMC migration during the development of vascular remodeling. AT₂R may be a potential target for the treatment of AT1-AA-induced vascular diseases.

Adaptations in autonomic nervous system regulation in normal and hypertensive pregnancy

There is an increase in basal sympathetic nerve activity (SNA) during normal pregnancy; this counteracts profound primary vasodilation. However, pregnancy also impairs baroreflex control of heart rate and SNA, contributing to increased mortality secondary to peripartum hemorrhage. Pregnancy-induced hypertensive disorders evoke even greater elevations in SNA, which likely contribute to the hypertension. Information concerning mechanisms is limited. In normal pregnancy, increased angiotensin II acts centrally to support elevated SNA. Hypothalamic sites, including the subfornical organ, paraventricular nucleus, and arcuate nucleus, are likely (but unproven) targets. Moreover, no definitive mechanisms for exaggerated sympathoexcitation in hypertensive pregnancy have been identified. In addition, normal pregnancy increases gamma aminobutyric acid inhibition of the rostral ventrolateral medulla (RVLM), a key brainstem site that transmits excitatory inputs to spinal sympathetic preganglionic neurons. Accumulated evidence supports a major role for locally increased production and actions of the neurosteroid allopregnanolone as one mechanism. A consequence is suppression of baroreflex function, but increased basal SNA indicates that excitatory influences predominate in the RVLM. However, many questions remain regarding other sites and factors that support increased SNA during normal pregnancy and, more importantly, the mechanisms underlying excessive sympathoexcitation in life-threatening hypertensive pregnancy disorders such as preeclampsia.

Cross-Talk between Oxidative Stress and Inflammation in Preeclampsia

The occurrence of hypertensive syndromes during pregnancy leads to high rates of maternal-fetal morbidity and mortality. Amongst them, preeclampsia (PE) is one of the most common. This review aims to describe the relationship between oxidative stress and inflammation in PE, aiming to reinforce its importance in the context of the disease and to discuss perspectives on clinical and nutritional treatment, in this line of research. Despite the still incomplete understanding of the pathophysiology of PE, it is well accepted that there are placental changes in pregnancy, associated with an imbalance between the production of reactive oxygen species and the antioxidant defence system, characterizing the placental oxidative stress that leads to an increase in the production of proinflammatory cytokines. Hence, a generalized inflammatory process occurs, besides the presence of progressive vascular endothelial damage, leading to the dysfunction of the placenta. There is no consensus in the literature on the best strategies for prevention and treatment of the disease, especially for the control of oxidative stress and inflammation. In view of the above, it is evident the important connection between oxidative stress and inflammatory process in the pathogenesis of PE, being that this disease is capable of causing serious implications on both maternal and fetal health. Reports on the use of anti-inflammatory and antioxidant compounds are analysed and still considered controversial. As such, the field is open for new basic and clinical research, aiming the development of innovative therapeutic approaches to prevent and to treat PE.

Prediction of pre-eclampsia: review of reviews

OBJECTIVE

Primary studies and systematic reviews provide estimates of varying accuracy for different factors in the prediction of pre-eclampsia. The aim of this study was to review published systematic reviews to collate evidence on the ability of available tests to predict pre-eclampsia, to identify high-value avenues for future research and to minimize future research waste in this field.

METHODS

MEDLINE, EMBASE and The Cochrane Library including DARE (Database of Abstracts of Reviews of Effects) databases, from database inception to March 2017, and bibliographies of relevant articles were searched, without language restrictions, for systematic reviews and meta-analyses on the prediction of pre-eclampsia. The quality of the included reviews was assessed using the AMSTAR tool and a modified version of the QUIPS tool. We evaluated the comprehensiveness of search, sample size, tests and outcomes evaluated, data synthesis methods, predictive ability estimates, risk of bias related to the population studied, measurement of predictors and outcomes, study attrition and adjustment for confounding.

RESULTS

From 2444 citations identified, 126 reviews were included, reporting on over 90 predictors and 52 prediction models for pre-eclampsia. Around a third (n = 37 (29.4%)) of all reviews investigated solely biochemical markers for predicting pre-eclampsia, 31 (24.6%) investigated genetic associations with pre-eclampsia, 46 (36.5%) reported on clinical characteristics, four (3.2%) evaluated only ultrasound markers and six (4.8%) studied a combination of tests; two (1.6%) additional reviews evaluated primary studies investigating any screening test for pre-eclampsia. Reviews included between two and 265 primary studies, including up to 25 356 688 women in the largest review. Only approximately half (n = 67 (53.2%)) of the reviews assessed the quality of the included studies. There was a high risk of bias in many of the included reviews, particularly in relation to population representativeness and study attrition. Over 80% (n = 106 (84.1%)) summarized the findings using meta-analysis. Thirty-two (25.4%) studies lacked a formal statement on funding. The predictors with the best test performance were body mass index (BMI) > 35 kg/m² , with a specificity of 92% (95% CI, 89-95%) and a sensitivity of 21% (95% CI, 12-31%); BMI > 25 kg/m² , with a specificity of 73% (95% CI, 64-83%) and a sensitivity of 47% (95% CI, 33-61%); first-trimester uterine artery pulsatility index or resistance index > 90^th centile (specificity 93% (95% CI, 90-96%) and sensitivity 26% (95% CI, 23-31%)); placental growth factor (specificity 89% (95% CI, 89-89%) and sensitivity 65% (95% CI, 63-67%)); and placental protein 13 (specificity 88% (95% CI, 87-89%) and sensitivity 37% (95% CI, 33-41%)). No single marker had a test performance suitable for routine clinical use. Models combining markers showed promise, but none had undergone external validation.

CONCLUSIONS

This review of reviews calls into question the need for further aggregate meta-analysis in this area given the large number of published reviews subject to the common limitations of primary predictive studies. Prospective, well-designed studies of predictive markers, preferably randomized intervention studies, and combined through individual-patient data meta-analysis are needed to develop and validate new prediction models to facilitate the prediction of pre-eclampsia and minimize further research waste in this field. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Multiple Autoantibodies against Cardiovascular Receptors as Biomarkers in Hypertensive Heart Disease

OBJECTIVES

The pathogenesis of hypertensive heart disease (HHD) remains unclear, which might include autoimmunity. The aim of the present study was to determine whether a relationship exists between the presence of autoantibodies against β1, β2, α1 adrenoreceptors, M2-muscarinic receptors, angiotensin II type1 receptors and HHD.

METHODS

In the present study, 44 patients diagnosed with HHD, 36 patients with hypertension, and 40 controls were also enrolled. The measurement of these 5 autoantibodies was performed by enzyme-linked immunosorbent assay.

RESULTS

The frequencies of autoantibodies against β1, β2, α1 adrenoreceptors, autoantibodies against M2-muscarinic receptors and autoantibodies against angiotensin II type1 receptors were significantly higher in patients with HHD, when compared to patients with hypertension and normal controls (all p < 0.001). In addition, the titers of these 5 autoantibodies significantly increased in patients with HHD. Patients who were positive for all 5 autoantibodies had larger left ventricular end-diastolic diameter (60.5 ± 4.9 vs. 57.8 ± 5.0 vs. 52.5 ± 5.3 mm) and worse left ventricular ejection fraction (45.0 ± 11.0 vs. 56.6 ± 10.4 vs. 57.8 ± 5.3%), when compared to patients not positive for all the 5 autoantibodies and patients negative for all the 5 autoantibodies (χ2 = 9.524, p = 0.009 and χ2 = 7.689, p = 0.021). Furthermore, a significant positive correlation was observed between each 2 autoantibodies of these 5 autoantibodies (all p < 0.001).

CONCLUSION

Multiple autoantibodies of cardiovascular receptors may be involved in the pathogenesis and may be predictive factors of HHD.

Downregulated low-density lipoprotein receptor-related protein 6 induces the maldevelopment of extravillous trophoblast via Wnt/β-catenin signaling pathway

Preeclampsia (PE), a special type of hypertensive disorder complicating pregnancy (HDCP), is highly associated with the migratory and invasive capacity of extravillous trophoblasts (EVTs). Here, we aimed to study the functions of low-density lipoprotein receptor-related protein 6 (LRP6) in PE pathogenesis. A comparative analysis of cellular gene expressions between placenta tissues collected from PE patients and normal pregnant women showed that the expressions of LRP6, β-catenin and matrix metallopeptidases/TIMP metallopeptidase inhibitors (MMPs/TIMPs) ratio in placentas of PE patients were much lower than the normal. Then, we constructed and transfected LRP6 siRNA (siLRP6) and LRP6 overexpression vectors into HTR6/SVneo cells. On the contrary to siLRP6, LRP6 overexpression could significant enhance cell viability, and strengthen the abilities of cell migration and invasion. Importantly, the overexpression of LRP6 could induce the upregulation of MMP-2 and MMP-9 levels, and downregulation of TIMPs. The mRNA and protein levels of β-catenin, an intracellular signal transducer of Wnt signaling pathway, were significantly up-regulated under the effects of LRP6 overexpression. XAV939, a Wnt/β-catenin pathway inhibitor, was introduced to confirm the involvement of Wnt/β-catenin pathway in functions of LRP6. The results of cell viability detection showed that XAV939 could significantly inhibit the positive effects of LRP6 overexpression on cell viability. Taken together, low-expressed LRP6 may be responsible of lower migration and invasion of EVTs and subsequent PE, and the mechanisms show a highly association with Wnt/β-catenin pathway.

Prospective biomarkers in preterm preeclampsia: A review

Preterm pre-eclampsia (prior to 37 weeks' gestation) remains a major cause of maternal and fetal morbidity and mortality particularly in low to middle income countries. Much research has focused on first and second trimester predictors of pre-eclampsia with the aim of allowing stratification of antenatal care and trialling of potential preventative and therapeutic agents. However, none have been shown to be of benefit in randomised controlled trials. In this literature review we critically evaluate predictive and diagnostic tests for preterm pre-eclampsia and discuss their clinical use and potential value in the management of preterm pre-eclampsia. We defined preterm pre-eclampsia as pre-eclampsia occurring prior to 37 weeks' gestation. Substantial progress has been made in the development of predictive screening tests for preterm pre-eclampsia, but further research is needed prior to their introduction and integration into routine clinical practice. The performance of diagnostic tests mainly utilising angiogenic and anti-angiogenic factors for determining time to delivery in later pregnancy currently hold more promise than first trimester predictive tests, possible reflecting the heterogeneity of pre-eclampsia.

Autoantibodies against angiotensin and adrenergic receptors: more than a biomarker?

Agonistic autoantibodies (AAs) directed against receptors of the sympathetic nervous system and the renin-angiotensin system have been suggested to contribute to cardiovascular and renal disease, in particular hypertension, preeclampsia, and graft failure in kidney transplantation patients. Consequently, they are now also being studied as biomarker for these conditions. This commentary summarizes our current understanding of these AAs, critically discussing whether they truly act as agonist, and focusing on the wide array of assays that are currently used for their quantification.

Avoiding excessive pregnancy weight gain to obtain better pregnancy outcomes in Taiwan

Pregnancy weight gain may be associated with adverse pregnancy outcomes. The article aims to explore the relationship between weight change and pregnancy outcome in the Taiwanese pregnant women.The retrospective cohort study enrolled women with vertex singleton pregnancy at University-associated Hospital between 2011 and 2014. Pregnancy weight change was separated into 3 groups, based on the Institute of Medicine (IOM) guidelines: below (n = 221); within (n = 544); and above (n = 382). Analysis of variance, χ tests, generalized linear models, and logistic regression models were used for statistical comparisons.Pregnant women with weight change above IOM guidelines had a significant increase in both maternal and perinatal complications compared with normal controls (odds ratio [OR] 1.65, 95% confidence interval [CI] 1.03-1.98; P = .043; OR 1.45, 95% CI 1.01-1.87; P = .049, respectively). This finding was not found in pregnant women with weight gain below IOM guidelines. Moreover, age (OR 1.08, 95% CI 1.02-1.15; P = .0011), pre-pregnancy weight (OR 1.04, 95% CI 1.01-1.09; P = .0008), pre-pregnancy body mass index (BMI; OR 1.15, 95% CI 1.06-1.30; P < .0001), weight at the time of delivery (OR 1.05, 95% CI 1.02-1.13; P < .0001) and BMI at the time of delivery (OR 1.15, 95% CI 1.06-1.39; P < .0001), all contributed to increased maternal complications but not perinatal complications, whereas parity (OR 0.23, 95% CI 0.12-0.41; P < .0001) and gestational age (OR 0.50, 95% CI 0.35-0.62; P < .001) were associated with fewer maternal complications.Our study reconfirmed that for Taiwanese pregnant women, the approximate pregnancy weight gain recommended by IOM in 2009 was associated with the fewest maternal and perinatal complications. If approximate pregnancy weight gain cannot be attained, even less weight gain during pregnancy is still reasonable without significantly and adversely affecting maternal and perinatal outcomes in Taiwan.

Autoantibody profiling on a plasmonic nano-gold chip for the early detection of hypertensive heart disease

The role of autoimmunity in cardiovascular (CV) diseases has been increasingly recognized. Autoimmunity is most commonly examined by the levels of circulating autoantibodies in clinical practices. Measurement of autoantibodies remains, however, challenging because of the deficiency of reproducible, sensitive, and standardized assays. The lack of multiplexed assays also limits the potential to identify a CV-specific autoantibody profile. To overcome these challenges, we developed a nanotechnology-based plasmonic gold chip for autoantibody profiling. This approach allowed simultaneous detection of 10 CV autoantibodies targeting the structural myocardial proteins, the neurohormonal regulatory proteins, the vascular proteins, and the proteins associated with apoptosis and coagulation. Autoantibodies were measured in four groups of participants across the continuum of hypertensive heart diseases. We observed higher levels of all 10 CV autoantibodies in hypertensive subjects (n = 77) compared with healthy participants (n = 30), and the autoantibodies investigated were related to each other, forming a highly linked network. In addition, we established that autoantibodies to troponin I, annexin-A5, and beta 1-adrenegic receptor best discriminated hypertensive subjects with adverse left ventricular (LV) remodeling or dysfunction (n = 49) from hypertensive subjects with normal LV structure and function (n = 28). By further linking these three significant CV autoantibodies to the innate and growth factors, we revealed a positive but weak association between autoantibodies to troponin I and proinflammatory cytokine IL-18. Overall, we demonstrated that this platform can be used to evaluate autoantibody profiles in hypertensive subjects at risk for heart failure.