Roles of the circulating renin-angiotensin-aldosterone system in human pregnancy

Importance of the (Pro)renin Receptor in Activating the Renin-Angiotensin System During Normotensive and Preeclamptic Pregnancies

PURPOSE OF REVIEW

For a healthy pregnancy to occur, a controlled interplay between the maternal circulating renin-angiotensin-aldosterone system (RAAS), placental renin-angiotensin system (RAS) and intrarenal renin-angiotensin system (iRAS) is necessary. Functionally, both the RAAS and iRAS interact to maintain blood pressure and cardiac output, as well as fluid and electrolyte balance. The placental RAS is important for placental development while also influencing the maternal circulating RAAS and iRAS. This narrative review concentrates on the (pro)renin receptor ((P)RR) and its soluble form (s(P)RR) in the context of the hypertensive pregnancy pathology, preeclampsia.

RECENT FINDINGS

The (P)RR and the s(P)RR have become of particular interest as not only can they activate prorenin and renin, thus influencing levels of angiotensin II (Ang II), but s(P)RR has now been shown to directly interact with and stimulate the Angiotensin II type 1 receptor (AT1R). Levels of both placental (P)RR and maternal circulating s(P)RR are elevated in patients with preeclampsia. Furthermore, s(P)RR has been shown to increase blood pressure in non-pregnant and pregnant rats and mice. In preeclamptic pregnancies, which are characterised by maternal hypertension and impaired placental development and function, we propose that there is enhanced secretion of s(P)RR from the placenta into the maternal circulation. Due to its ability to both activate prorenin and act as an AT1R agonist, excess maternal circulating s(P)RR can act on both the maternal vasculature, and the kidney, leading to RAS over-activation. This results in dysregulation of the maternal circulating RAAS and overactivation of the iRAS, contributing to maternal hypertension, renal damage, and secondary changes to neurohumoral regulation of fluid and electrolyte balance, ultimately contributing to the pathophysiology of preeclampsia.

The Menstrual Health Manager (MHM): A Resource to Reduce Discrepancies Between Science and Practice in Sport and Exercise

Inadequate research on female health and performance; the complexity of the research; low menstrual health literacy of athletes, coaches, and support staff; and ethical and cultural sensitivities are all recognized as barriers to effective health monitoring for females in sports. Frameworks have been developed for academics to follow to help improve the quality of female-specific research. However, a similar resource that enables correct terminology, and use of health monitoring techniques has not been provided for sporting organizations, coaches, support staff or athletes. Therefore, this critical commentary presents a new resource, the Menstrual Health Manager. This resource may be used to determine the level of menstrual health monitoring detail that may be used by organisations, coaches or athletes, and specifies what reproductive health details the data will provide. This resource aims to provide organizations and coaches with a means of understanding the data that inform their decisions for female athletes. Utilization of this resource may aid in the consistent use of terminology and methods for female-specific health monitoring in both sports and research.

Challenges and opportunities in patients with adult congenital heart disease, a narrative review

Adult congenital heart disease Pregnancy Transition of care Challenges heart failure.

The Molecular Basis of the Augmented Cardiovascular Risk in Offspring of Mothers with Hypertensive Disorders of Pregnancy

The review examines the impact of maternal preeclampsia (PE) on the cardiometabolic and cardiovascular health of offspring. PE, a hypertensive disorder of pregnancy, is responsible for 2 to 8% of pregnancy-related complications. It significantly contributes to adverse outcomes for their infants, affecting the time of birth, the birth weight, and cardiometabolic risk factors such as blood pressure, body mass index (BMI), abdominal obesity, lipid profiles, glucose, and insulin. Exposure to PE in utero predisposes offspring to an increased risk of cardiometabolic diseases (CMD) and cardiovascular diseases (CVD) through mechanisms that are not fully understood. The incidence of CMD and CVD is constantly increasing, whereas CVD is the main cause of morbidity and mortality globally. A complex interplay of genes, environment, and developmental programming is a plausible explanation for the development of endothelial dysfunction, which leads to atherosclerosis and CVD. The underlying molecular mechanisms are angiogenic imbalance, inflammation, alterations in the renin-angiotensin-aldosterone system (RAAS), endothelium-derived components, serotonin dysregulation, oxidative stress, and activation of both the hypothalamic-pituitary-adrenal axis and hypothalamic-pituitary-gonadal axis. Moreover, the potential role of epigenetic factors, such as DNA methylation and microRNAs as mediators of these effects is emphasized, suggesting avenues for future research and therapeutic interventions.

Doppler ultrasonographic measurements of the lateral digital palmar artery in pregnant mares

Cardiovascular changes have been reported in late pregnancy in mares. However, there are no data on changes in peripheral blood flow. Doppler ultrasound represents a sensitive method for assessing the blood flow directed to the hoof. The aims of this study were to evaluate the blood flow parameters of the lateral palmar digital artery (LPDA) in pregnant mares and to assess intra- and interrater agreement between two observers with different levels of experience. The LPDAs of pregnant Italian Standardbred mares were examined. The vessels were located with B-mode ultrasound and analyzed with color and pulsed wave Doppler. The following parameters were recorded by the operators: heart rate (HR), peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI). Measurements were performed between 2 and 3 months of gestation (T1), in the last month of pregnancy (T2) and a week after delivery (T3). Seventeen mares aged 3-18 years met the inclusion criteria. Ultrasound examinations of the LPDA were subjectively easy to perform and well tolerated by the mares. Interrater and intrarater agreement were good and moderate, respectively. The HR was higher at T2 than at T1 and T3. The PSV and RI changed significantly during pregnancy, with higher values at T2 and T3, whereas the EDV remained unchanged throughout the examination. Doppler examination showed that peripheral flow changes were present in mares in late pregnancy. However, the persistence of higher values after delivery invites further investigation to assess the correlation between metabolic/endocrine changes related to pregnancy and Doppler parameters.

Associations of salivary aldosterone levels during pregnancy with maternal blood pressure and birth weight-for-gestational age in a Mexico City birth cohort

OBJECTIVE

To determine associations of maternal salivary aldosterone with blood pressure (BP) in pregnancy and infant birth weight-for-gestational age (BWGA).

METHODS

We measured maternal salivary aldosterone, BP and BWGA z-scores in 471 Mexico City pregnancy cohort participants and performed multivariable linear regression of BP and BWGA on log-aldosterone levels.

RESULTS

Log-aldosterone was positively associated with diastolic BP (β = 0.12 95% CI: 0.04, 0.21). There were no main effects of log-aldosterone on BWGA. However, we detected an interaction between log-aldosterone and BP in association with BWGA; higher log-aldosterone was associated with lower BWGA in the lowest (β = -0.12, 95% CI: -0.26, 0.02) and highest (β = -0.12, 95% CI: -0.29, 0.06) BP tertiles. In contrast, in the middle BP tertile the association was positive (β = 0.09, 95% CI: -0.02, 0.20), p for interaction = 0.03.

CONCLUSION

Higher maternal salivary aldosterone is positively associated with diastolic BP and may affect fetal growth differently depending on concurrent maternal blood pressure.

Clinical features, laboratory findings and treatment of juxtaglomerular cell tumors: a systemic review

Juxtaglomerular cell tumors (JGCTs) or reninoma are rare kidney tumors leading to secondary hypertension, and the non-specific clinical manifestations bring about challenges to the diagnosis. This study is to summarize the clinical features, laboratory findings, and treatment of JGCTs. The PubMed, EMBASE database, and manual search were utilized to find all cases, and 158 reports containing 261 patients were identified. Data on patients' demographics, clinical features, diagnostic methods, and treatment options were collected and analyzed. JGCTs occurred predominantly in female patients (female to male ratio, 2.1:1). The median age of patients was 25 years (IQR:18-34 years). Hypertension (97.24%) was the cardinal manifestation. Hypokalemia was reported in 78.71% (159/202) of subjects, and normal serum potassium accounted for 20.79% (42/202). In cases with assessed plasma renin activity (PRA) levels, the median PRA was 7.89 times the upper limit of normal (IQR:3.58-14.41), and 3.82% (5/131) of cases in the normal range. Tumors were detected in 97.8% (175/179) computed tomography (CT), 94.7% (72/76) magnetic resonance imaging (MRI), and 81.5% (110/135) ultrasound, respectively. For 250/261 patients undergoing surgical procedures, 89.14% (197/221), 94.94% (150/158), and 100% (131/131) of patients were restored to normal blood pressure, PRA, and serum potassium, respectively. JGCTs are commonly associated with hypertension, hypokalemia, and hyperreninemia, whereas patients with normotension, normokalemia, and PRA should be systematically pursued after drug-elution lasting for 2 weeks. CT and MRI are more sensitive imaging diagnostic methods. The blood pressure and biochemical parameters of most patients returned to normal after surgery.

High-Risk Congenital Heart Disease in Pregnancy

High-risk congenital heart disease (CHD) in pregnancy presents a complex clinical challenge. With improved medical care and increased survival rates, a growing population of adults with complex CHD are surviving to adulthood, including women of reproductive age. This chapter focuses on risk stratification and management of pregnant women with high-risk CHD, emphasizing the importance of considering both anatomical and physiological complexity. Maternal physiological changes, such as blood volume increase, cardiac output changes, and alterations in vascular resistance, can significantly impact high-risk CHD patients. Management of high-risk CHD in pregnancy necessitates a multidisciplinary approach and individualized care.

Active plasma renin concentration throughout healthy and complicated pregnancy: a systematic review and meta-analysis

BACKGROUND

Pregnancy is characterized by profound circulatory changes and compensatory adjustments in the renin-angiotensin-aldosterone system (RAAS). Differences in regulatory response may antedate or accompany vascular complicated pregnancy. We performed a systematic review and meta-analysis to delineate the trajectory of active plasma renin concentration (APRC) in healthy pregnancy and compare this to complicated pregnancy.

METHODS

We performed a systematic review and meta-analysis on APRC during normotensive and hypertensive pregnancies, using PubMed (NCBI) and Embase (Ovid) databases. We included only studies reporting measurements during pregnancy together with a nonpregnant reference group measurement. Risk of bias was assessed with QUIPS. Ratio of the mean (ROM) and 95% confidence intervals (CI) of APRC values between pregnant and nonpregnant women were estimated for predefined intervals of gestational age using a random-effects model. Meta-regression was used to analyze APRC over time.

RESULTS

In total, we included 18 studies. As compared to nonpregnant, APRC significantly increased as early as the first weeks of healthy pregnancy and stayed increased throughout the whole pregnancy (ROM 2.77; 95% CI 2.26-3.39). APRC in hypertensive complicated pregnancy was not significantly different from nonpregnancy (ROM 1.32; 95% CI 0.97-1.80).

CONCLUSION

Healthy pregnancy is accompanied by a profound rise in APRC in the first trimester that is maintained until term. In hypertensive complicated pregnancy, this increase in APRC is not observed.

Placental and Renal Pathways Underlying Pre-Eclampsia

Pre-eclampsia is a serious complication of pregnancy characterized by a state of multiorgan hypertensive disorders, with or without proteinuria and possible multiorgan dysfunction. Chronic kidney disease is an established risk factor for the development of pre-eclampsia, as angiogenic homeostasis is altered and the maternal circulation is already hypertensive. Facing pre-eclampsia in the context of chronic kidney disease is a challenging emergency for both the mother and the fetus. The clinical features and the management of this multi-organ disorder are clearly defined in the modern literature but the underlying pathophysiologic mechanisms remain not fully elucidated. Understanding the pathophysiology that mediates the onset of pre-eclampsia itself and in synergy with chronic kidney disease is fundamental for developing prompt prevention strategies, treatment planning, and patient counseling. This review aims to summarize the main molecular mechanisms involved in the process of pre-eclampsia, with a particular focus on the role of the kidneys and hormonal pathways related to renal function in normal pregnancy and pre-eclamptic syndromes.

Acute Myocardial Infarction in Pregnancy

Pregnancy-associated myocardial infarction is an overall uncommon event, but can be associated with significant maternal and fetal morbidity and mortality. In contrast to myocardial infarction in the general nonpregnant population, the mechanism of pregnancy-associated myocardial infarction is most commonly due to nonatherosclerotic mechanisms such as coronary dissection, vasospasm, or thromboembolism. The diagnosis of pregnancy-associated myocardial infarction can be challenging, requiring a high index of suspicion for prompt recognition and management. Furthermore, the management of pregnancy-associated myocardial infarction can be complex due to maternal and fetal considerations and may vary based on the specific underlying mechanism of the myocardial infarction. This review aims to review the recent literature on pregnancy-associated myocardial infarction and summarize the epidemiology, mechanisms, diagnosis, and treatment strategies for this uncommon entity.

The dilemma of sodium intake in preeclampsia: beneficial or detrimental?

Preeclampsia (PE) is a disorder involving de novo development of hypertension plus end organ damage after 20 weeks of gestation. PE is considered to be a heterogeneous disease. There are 2 main types of PE: early-onset (<34 weeks of gestation), which is considered to be a placental disorder and is associated with vasoconstriction, low cardiac output, and placental hypoperfusion and organ damage due to decreased microcirculation to maternal organs; and late-onset PE, which is primarily a disorder of pregnant women with obesity, diabetes, and/or cardiovascular abnormalities. In late-onset PE, there is avid sodium reabsorption by the maternal kidneys, causing hypervolemia and increased cardiac output, along with vasodilatation causing venous congestion of organs. Although PE has been a well-known disease for a long time, it is interesting to note that there is no specific sodium (salt) intake recommendation for these patients. This may be due to the fact that studies since as far back as the 1900s have shown conflicting results, and the reasons for the inconsistent findings have not been fully explained; furthermore, the type of PE in these studies was not specifically defined. Some studies suggest that sodium restriction may be detrimental in early-onset PE, but may be feasible in late-onset PE. To explore this paradox, the current review explains the hemodynamic factors involved in these 2 types of PE, summarizes the findings of the current studies, and highlights the knowledge gaps and the research needed to determine whether increase or restriction of salt or sodium intake is beneficial in different types of PE.

Regulation of vascular angiotensin II type 1 and type 2 receptor and angiotensin-(1-7)/MasR signaling in normal and hypertensive pregnancy

Normal pregnancy (Norm-Preg) is associated with a slight reduction in blood pressure (BP) and decreased BP response to vasoconstrictor stimuli such as angiotensin II (Ang II), although the renin-angiotensin-aldosterone system (RAAS) is upregulated. Preeclampsia (PE) is a complication of pregnancy manifested as hypertension-in-pregnancy (HTN-Preg), and dysregulation of angiotensin biosynthesis and signaling have been implicated. Ang II activates vascular Ang II type-1 receptor (AT1R) and Ang II type-2 receptor (AT2R), while angiotensin-(1-7) promotes Ang-(1-7)/MasR signaling. The role of AT1R in vasoconstriction and the activated cellular mechanisms are well-characterized. The sensitivity of vascular AT1R to Ang II and consequent activation of vasoconstrictor mechanisms decrease during Norm-Preg, but dramatically increase in HTN-Preg. Placental ischemia in late pregnancy could also initiate the release of AT1R agonistic autoantibodies (AT1AA) with significant impact on endothelial dysfunction and activation of contraction pathways in vascular smooth muscle including [Ca2+]c and protein kinase C. On the other hand, the role of AT2R and Ang-(1-7)/MasR in vascular relaxation, particularly during Norm-Preg and PE, is less clear. During Norm-Preg, increases in the expression/activity of vascular AT2R and Ang-(1-7)/MasR promote the production of endothelium-derived relaxing factors such as nitric oxide (NO), prostacyclin and endothelium-derived hyperpolarizing factor leading to generalized vasodilation. Aortic segments of Preg rats show prominent endothelial AT2R staining and increased relaxation and NO production in response to AT2R agonist CGP42112A, and treatment with AT2R antagonist PD123319 enhances phenylephrine-induced contraction. Decreased vascular AT2R and Ang-(1-7)/MasR expression and receptor-mediated mechanisms of vascular relaxation have been suggested in HTN-Preg animal models, but their role in human PE needs further testing. Changes in angiotensin-converting enzyme-2 (ACE2) have been observed in COVID-19 patients, and whether ACE2 influences the course of COVID-19 viral infection/immunity in Norm-Preg and PE is an intriguing area for research.

Approach to the Patient: Reninoma

A reninoma is a functional tumor of afferent arteriolar juxtaglomerular cells that secretes the enzyme renin, leading to hyperactivation of the renin-angiotensin-aldosterone system. Reninoma is a potentially curable cause of pathological secondary hyperaldosteronism that results in often severe hypertension and hypokalemia. The lack of suppression of plasma renin contrasts sharply with the much more common primary aldosteronism, but diagnosis is often prompted by screening for that condition. The major differential diagnosis of reninoma is renovascular hypertension. Fewer than 200 cases of reninoma have been described. Reninomas have been reported across a broad demographic but have a 2:1 predilection for women, often of childbearing age. Aldosterone receptor blockade, angiotensin-converting enzyme inhibitors, or angiotensin receptor blockers offer effective medical management but are contraindicated in pregnancy, so surgical curative resection is ideal. The current optimal imaging and biochemical workup of reninoma and management approach (ideally, tumor excision with subtotal renal resection) are described.

Maternal plasma angiotensin 1-7 concentration is related to twin pregnancy chorionicity in the third trimester of pregnancy

Introduction

Twin gestation is related to a higher risk of hypertensive disorders in pregnancy with possible risk stratification depending on chorionicity. It may be related to differences in plasma renin-angiotensin-aldosterone components between monochorionic and dichorionic twin pregnancies. The study aimed to analyze the plasma ANG II and ANG 1-7 concentrations in women with monochorionic and dichorionic twin gestation.

Methods

A prospective observational study included 79 women between 32 and 34 weeks of gestation with twin pregnancy (31 with monochorionic gestation and 48 with dichorionic gestation). Angiotensin II and angiotensin 1-7 concentrations were measured in the collected blood samples.

Results

No significant differences were observed in angiotensin II concentrations between the dichorionic and monochorionic group with significantly higher levels of angiotensin 1-7 being observed in the dichorionic group. Angiotensin 1-7 level was higher than angiotensin II in 20 women (64.5%) in the monochorionic group and in 42 women (87.5%, p=0.01) in the dichorionic group. Higher plasma concentrations of angiotensin II and lower concentrations of angiotensin 1-7 were found in 5 women with gestational hypertension and in 3 with preeclampsia compared to normotensive women.

Discussion

It is the first study investigating angiotensin II and angiotensin 1-7 in twin pregnancies regarding chorionicity. Our results showed that plasma angiotensin 1-7 concentration was related to chorionicity, while plasma angiotensin II level was not. In most women with twin gestation angiotensin 1-7 concentration exceeded the concentration of angiotensin II. A switch in the relation between angiotensin II and angiotensin 1-7 was observed in hypertensive pregnant women.

Sex differences in blood pressure regulation and hypertension: renal, hemodynamic, and hormonal mechanisms

The teleology of sex differences has been argued since at least as early as Aristotle's controversial Generation of Animals more than 300 years BC, which reflects the sex bias of the time to contemporary readers. Although the question "why are the sexes different" remains a topic of debate in the present day in metaphysics, the recent emphasis on sex comparison in research studies has led to the question "how are the sexes different" being addressed in health science through numerous observational studies in both health and disease susceptibility, including blood pressure regulation and hypertension. These efforts have resulted in better understanding of differences in males and females at the molecular level that partially explain their differences in vascular function and renal sodium handling and hence blood pressure and the consequential cardiovascular and kidney disease risks in hypertension. This review focuses on clinical studies comparing differences between men and women in blood pressure over the life span and response to dietary sodium and highlights experimental models investigating sexual dimorphism in the renin-angiotensin-aldosterone, vascular, sympathetic nervous, and immune systems, endothelin, the major renal sodium transporters/exchangers/channels, and the impact of sex hormones on these systems in blood pressure homeostasis. Understanding the mechanisms governing sex differences in blood pressure regulation could guide novel therapeutic approaches in a sex-specific manner to lower cardiovascular risks in hypertension and advance personalized medicine.

Impact of Aging and Cellular Senescence in the Pathophysiology of Preeclampsia

The incidence of hypertensive disorders of pregnancy is increasing, which may be due to several factors, including an increased age at pregnancy and more comorbid health conditions during reproductive years. Preeclampsia, the most severe hypertensive disorder of pregnancy, has been associated with an increased risk of future disease, including cardiovascular and kidney diseases. Cellular senescence, the process of cell cycle arrest in response to many physiologic and maladaptive stimuli, may play an important role in the pathogenesis of preeclampsia and provide a mechanistic link to future disease. In this article, we will discuss the pathophysiology of preeclampsia, the many mechanisms of cellular senescence, evidence for the involvement of senescence in the development of preeclampsia, as well as evidence that cellular senescence may link preeclampsia to the risk of future disease. Lastly, we will explore how a better understanding of the role of cellular senescence in preeclampsia may lead to therapeutic trials. © 2023 American Physiological Society. Compr Physiol 13:5077-5114, 2023.

Severe pre-eclampsia as a rare cause of profound hyponatraemia

Profound hyponatraemia, defined as sodium <125 mmol/L, is a very rare complication of pre-eclampsia (PET) with a relative paucity of cases reported. Pre-eclampsia is a multisystem disorder with a maternal mortality of up to 20%. Hyponatraemia is associated with disease severity, twin pregnancy, advanced maternal age, in vitro fertilisation and HELLP (haemolysis, elevated liver enzymes and low platelets). The authors present the case of a low-risk nulliparous woman presenting with frontal headache and normal BP at 31+2 weeks gestation. Laboratory investigations confirmed a sodium of 123 mmol/L. Her urine protein creatinine ratio was 322 mg/mmol. She developed PET (BP 171/100 mm Hg) refractory to pharmacological management. She underwent an emergency lower segment caesarean section and was delivered of a live neonate. The maternal serum sodium normalised within 24 hours. Hyponatraemia should be regarded as a marker of severity in the setting of pre-eclampsia and may be an indication for an expedited delivery. Prompt management is required to prevent convulsions, maternal mortality and adverse fetal outcomes.

Differential expression of the angiotensin receptors (AT1, AT2, and AT4) in the placental bed of HIV-infected preeclamptic women of African ancestry

The Renin-Angiotensin-Aldosterone System (RAAS) is implicated in the pathophysiology of preeclampsia (PE). There is a paucity of data on uteroplacental angiotensin receptors AT1-2 and 4. We evaluated the immunoexpression of AT1R, AT2R, and AT4R within the placental bed of PE vs. normotensive (N) pregnancies stratified by HIV status. Placental bed (PB) biopsies (n = 180) were obtained from N and PE women. Both groups were stratified by HIV status and gestational age into early-and late onset-PE. Immuno-labeling of AT1R, AT2R, and AT4R was quantified using morphometric image analysis. Immunostaining of PB endothelial cells (EC) and smooth muscle cells of spiral arteries (VSMC) displayed an upregulation of AT1R expression compared to the N group (p < 0.0001). Downregulation of AT2R and AT4R expression was observed in PE vs. N group (p = 0.0042 and p < 0.0001), respectively. AT2R immunoexpression declined between HIV+ve and HIV-ve groups, while AT1R and AT4R displayed an increase. An increase in AT1R expression was noted in the EOPE-ve/+ve and LOPE-ve/+ve compared to N-ve/N+ve. In contrast, AT2R and AT4R expression decreased in EOPE-ve/+ve and LOPE-ve/+ve compared to N-ve/N+ve. We demonstrate a significant downregulation of AT2R and AT4R with a concomitant elevated AT1R immunoexpression within PB of HIV-infected PE women. In addition, a decline in AT2R and AT4R with an increase in AT1R immunoexpression in PE, EOPE, and LOPE vs. normotensive pregnancies, irrespective of HIV status. Thus highlighting differential immunoexpression of uteroplacental RAAS receptors based on pregnancy type, HIV status, and gestational age.

Pregnancy-specific beta-1-glycoprotein 1-enriched exosomes are involved in the regulation of vascular endothelial cell function during pregnancy

INTRODUCTION

Pregnancy is a dynamic time period associated with significant physiological changes in the cardiovascular system. It is well known that during pregnancy, the placenta secretes a variety of molecular signals, including exosomes, into the maternal circulation to adapt to increased blood volume and maintain blood pressure at normotensive levels.

METHODS

In the present study, we compared the effects of exosomes derived from the peripheral blood serum of nonpregnant women (NP-Exo) and pregnant women with uncomplicated pregnancy (P-Exo) on endothelial cell function. We also analyzed the proteomic profiles of these two groups of exosomes and the molecular mechanisms underlying the effect of exosome cargoes on vascular endothelial cell function.

RESULTS

We found that P-Exo were positively involved in regulating the function of human umbilical vein endothelial cell (HUVEC) and promoting the release of nitric oxide (NO). Furthermore, we revealed that trophoblast-derived pregnancy-specific beta-1-glycoprotein 1 (PSG1)-enriched exosomes treatment induced the promotion of HUVEC proliferation and migration as well as the release of NO. In addition, we found that P-Exo maintained blood pressure at normal levels in mice.

DISCUSSION

These results suggested that PSG1-enriched exosomes derived from maternal peripheral blood regulate the function of vascular endothelial cells and play an important role in maintaining maternal blood pressure during pregnancy.

Appraising the Preclinical Evidence of the Role of the Renin-Angiotensin-Aldosterone System in Antenatal Programming of Maternal and Offspring Cardiovascular Health Across the Life Course: Moving the Field Forward: A Scientific Statement From the American Heart Association

There is increasing interest in the long-term cardiovascular health of women with complicated pregnancies and their affected offspring. Emerging antenatal risk factors such as preeclampsia appear to increase the risk of hypertension and cardiovascular disease across the life course in both the offspring and women after pregnancy. However, the antenatal programming mechanisms responsible are complex and incompletely understood, with roots in alterations in the development, structure, and function of the kidney, heart, vasculature, and brain. The renin-angiotensin-aldosterone system is a major regulator of maternal-fetal health through the placental interface, as well as kidney and cardiovascular tissue development and function. Renin-angiotensin-aldosterone system dysregulation plays a critical role in the development of pregnancy complications such as preeclampsia and programming of long-term adverse cardiovascular health in both the mother and the offspring. An improved understanding of antenatal renin-angiotensin-aldosterone system programming is crucial to identify at-risk individuals and to facilitate development of novel therapies to prevent and treat disease across the life course. Given the inherent complexities of the renin-angiotensin-aldosterone system, it is imperative that preclinical and translational research studies adhere to best practices to accurately and rigorously measure components of the renin-angiotensin-aldosterone system. This comprehensive synthesis of preclinical and translational scientific evidence of the mechanistic role of the renin-angiotensin-aldosterone system in antenatal programming of hypertension and cardiovascular disease will help (1) to ensure that future research uses best research practices, (2) to identify pressing needs, and (3) to guide future investigations to maximize potential outcomes. This will facilitate more rapid and efficient translation to clinical care and improve health outcomes.

Prevalence and Correlates of Elevated NT-proBNP in Pregnant Women in the General U.S. Population

BACKGROUND

Physiologic changes in N-terminal pro-B-type natriuretic peptide (NT-proBNP) across trimesters of pregnancy have not been well studied.

OBJECTIVES

The authors aimed to measure NT-proBNP in adult women, by pregnancy status and trimester, in a nationally representative sample from the National Health and Nutrition Examination Survey 1999 to 2004.

METHODS

We conducted a cross-sectional analysis of 2,134 women (546 pregnant) aged 20 to 40 years without a history of cardiovascular disease.

RESULTS

Among pregnant women in the first trimester, the prevalence of elevated NT-proBNP (>125 pg/mL) was 20.0% (SE, 6.6%) compared to 2.4% (SE, 0.8%) among women in the third trimester and 8.0% among nonpregnant women. After adjustment for demographics and cardiovascular risk factors, NT-proBNP was 44% higher (absolute difference 26.4 [95% CI: 11.2-41.6] pg/mL) in the first trimester of pregnancy compared to nonpregnant women. Among pregnant women only, adjusted NT-proBNP was 46% lower (absolute difference -22.2 [95% CI: -36.9 to -7.5] pg/mL) in women in the third trimester compared to women in the first trimester. NT-proBNP was inversely associated with body mass index and with systolic blood pressure.

CONCLUSIONS

Women in the first trimester of pregnancy had significantly higher NT-proBNP than those in the third trimester and compared to similarly aged nonpregnant women. The dynamic nature of NT-proBNP should be taken into consideration when ordering NT-proBNP lab tests in pregnant women.

Preeclampsia is associated with reduced renin, aldosterone, and PlGF levels, and increased sFlt-1/PlGF ratio, and specific angiotensin-converting enzyme Ins-Del gene variants

We investigated the association of angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism with preeclampsia (PE) in Tunisian women. ACE I/D genotyping was done by PCR in 342 pregnant women with PE and 289 healthy pregnant women. The association between ACE I/D and PE and associated features were also evaluated. Decreased active renin concentration, plasma aldosterone concentration, and placental growth factor (PlGF) were observed in PE cases, while soluble fms-like tyrosine kinase-1 (sFlt-1)/PlGF ratio was significantly higher in the PE group. Distribution of ACE I/D alleles and genotypes were comparable between women with PE and control women. A significant difference in the frequency of the I/I genotype was seen between PE cases and control women according to the recessive model, with a trend towards association in the codominant model. Carriers of the I/I genotype had significantly higher infant birth weights compared to the I/D and the D/D genotype carriers. A dose-dependent relationship was also seen in VEGF and PlGF plasma levels and specific ACE I/D genotypes, with the lowest VEGF levels seen in the I/I genotype carriers compared to the D/D genotype carriers. Similarly, the I/I genotype carriers had the lowest PlGF levels compared to I/D and D/D genotype carriers. Furthermore, when studying the linkage between PE features, we found a positive correlation between PAC and PIGF. Our study suggests a role for ACE I/D polymorphism in the pathogenesis of PE, possibly through modulating VEGF and PlGF levels and infant birth weight, and highlights the relationship between PAC and PlGF.

Aortic Dissection and COVID-19 Pneumonia in a Pregnant Woman at 34 Weeks of Gestation

Between 0.1% and 0.3% of all aortic dissections occur during pregnancy. Arterial hypertension, connective tissue disorders, and congenital cardiovascular anomalies-including bicuspid aortic valves-are well-known risk factors. The causality between pregnancy and aortic dissection is unclear, but there have been some observations that COVID-19 illness may increase the risk. This report describes a pregnant woman at 34 weeks of gestation who had a bicuspid aortic valve and experienced an acute aortic dissection while ill with COVID-19 pneumonia. Computed tomography confirmed a type A aortic dissection and bilateral patchy pulmonary opacities. Cesarean delivery was performed, followed by replacement of the aortic valve with a mechanical aortic prosthesis and reconstruction of the ascending aorta and hemiarch. The intraoperative course was uneventful, and the patient was successfully weaned from mechanical ventilation after 51 hours. COVID-19 during pregnancy seems to increase the risk for aortic dissection, although there is no evidence base for an association. Because guidelines for diagnosis and treatment in such complex cases are lacking, care from a multidisciplinary team is crucial for successful outcomes.

Salt Sensitivity of Blood Pressure in Women

Several clinical and large population studies indicate that women are more salt-sensitive than men, yet the precise mechanisms by which the sexually dimorphic onset manifests remains incompletely understood. Here, we evaluate recent epidemiological data and highlight current knowledge from studies investigating sex-specific mechanisms of salt-sensitive blood pressure (SSBP). Emerging evidence indicates that women of all ethnicities are more salt-sensitive than men, at all ages both premenopausal and postmenopausal. However, menopause exacerbates severity and prevalence of SSBP, suggesting that female sex chromosomes predispose to and female sex hormones mitigate SSBP. Results from both human and rodent studies support the contribution of enhanced and inappropriate activation of the aldosterone-ECMR (endothelial cell mineralocorticoid receptor) axis promoting vascular dysfunction in females. Increases in adrenal response to angiotensin II, in association with higher ECMR expression and activation of endothelial ENaC (epithelial sodium channel) in females compared to males, are emerging as central players in the development of endothelial dysfunction and SSBP in females. Female sex increases the prevalence and susceptibility of SSBP and sex hormones and sex chromosome complement may exert antagonistic effects in the development of the female heightened SSBP.

The effect of pregnancy on meibomian gland, tear film, cornea and anterior segment parameters

AIM

In this prospective study, we aimed to examine the effect of physiological and pathological changes that occur during pregnancy in regard to Meibomian Gland (MG) structure, tear film, cornea and anterior segment parameters.

METHODS

The following groups were compared: 49 eyes of 49 pregnant women at 16-20 weeks of pregnancy (P16 Group), 46 eyes of 46 pregnant women at 32-36 weeks of pregnancy (P32 Group) and 51 eyes of 51 participants who were not pregnant (P0 Group). The groups were compared in terms of the first break-up time (NIF-BUT) and average break-up time (NIAvg-BUT) values. Non-contact meibography and MG loss rates were also compared.

RESULTS

The groups were found to be compatible in terms of age (P=0.052). The mean NIF-BUT values in the P16, P32 and P0 groups were 4.7 ±2.7, 6 ±3 and 6.7 ±3.1 seconds, respectively (P=0.055). The mean MG loss rates for the upper lid in the P16, P32 and P0 groups were 35.3%±12.6, 33.4%±11.4 and 15.5%±5.4, respectively. The loss rates for the lower lid in the P16, P32 and P0 groups were found to be 40.5%±18.6, 40.5%± 14.4 and 20.1%±8.1, respectively (P=0.000, p=0.000). The mean anterior chamber value (ACV) was found in the P16, P32 and P0 groups with 160.8 ±31.8, 150.9 ±26.5 and 165.9 ±26.5 µm³, respectively (P=0.035).

CONCLUSION

MG loss was found to be higher in pregnant groups compared to the non-pregnant groups. We found minimal instability in the tear film of the pregnant groups. We believe that pregnant women should be followed closely in terms of ocular surface diseases.

Perioperative Anesthetic Management of the Pregnant Patient With Congenital Heart Disease Undergoing Cardiac Intervention: A Systematic Review

Maternal congenital heart disease is increasingly prevalent, and has been associated with a significantly increased risk of maternal, obstetric, and neonatal complications. For patients with CHD who require cardiac interventions during pregnancy, there is little evidence-based guidance with regard to optimal perioperative management. The periprocedural management of pregnant patients with congenital heart disease requires extensive planning and a multidisciplinary teams-based approach. Anesthesia providers must not only be facile in the management of adult congenital heart disease, but cognizant of the normal, but significant, physiologic changes of pregnancy.

Proteome-wide and matrisome-specific atlas of the human ovary computes fertility biomarker candidates and open the way for precision oncofertility

Our modern era is witnessing an increasing infertility rate worldwide. Although some of the causes can be attributed to our modern lifestyle (e.g., persistent organic pollutants, late pregnancy), our knowledge of the human ovarian tissue has remained limited and insufficient to reverse the infertility statistics. Indeed, all efforts have been focused on the endocrine and cellular function in support of the cell theory that dates back to the 18th century, while the human ovarian matrisome is still under-described. Hereby, we unveil the extracellular side of the story during different periods of the ovary life, demonstrating that follicle survival and development, and ultimately fertility, would not be possible without its involvement. We examined the human ovarian matrisome and described its remodeling from prepuberty until menopause, creating the first ovarian proteomic codex. Here, we confidently identified and quantified 98 matrisome proteins present in the three ovary groups. Among them, 26 were expressed differently among age groups, delineating a peculiar matrisomal fingerprint at each stage. Such proteins could be potential biomarkers phenotyping ovarian ECM at each age phase of female reproductive life. Beyond proteomics, our study presents a unique approach to understanding the data and depicting the spatiotemporal ECM-intracellular signaling networks and remodeling with age through imaging, advanced text-mining based on natural language processing technology, machine learning, and data sonification. Our findings provide essential context for healthy ovarian physiology, identifying and characterizing disease states, and recapitulating physiological tissues or development in vitro. This comprehensive proteomics analysis represents the ovarian proteomic codex and contributes to an improved understanding of the critical roles that ECM plays throughout the ovarian life span.

Effect of the number of parity on right heart chamber quantification

INTRODUCTION

Pregnancy is a process that can cause several physiologic changes to the cardiovascular system such as ventricular hypertrophy and dilation of cardiac chambers. Although there are studies about pregnancy-related changes in echocardiographic examination; there is no data about the long-term effects of parity on these alterations. Therefore, we evaluated the long-term effect of pregnancy on right ventricular (RV) dilation and RV hypertrophy and their relation to the parity number.

METHODS

This prospective study included a total of 600 women (200 consecutive women who had no parity, 200 women who had a parity number of 1 to 4 and 200 women who had a parity number of more than 4). Right chambers' measurements were compared between the groups.

RESULTS

In echocardiographic analysis, RV and right atrial dimensions and areas and RV wall thickness were higher in parous women. On the other hand, RV systolic function parameters were significantly lower in parous women. These significant changes showed a gradual increase or decrease by increasing parity number. By multivariate hierarchical logistic regression analysis, the four independent factors that increased the risk of RV dilation were age (OR: 1.16 CI: 1.10-1.20), body mass index (OR: 1.05, CI: 1.02-1.08), smoking (OR: 1.87, CI: 1.28-4.02), and giving a birth (OR: 3.94 CI: 1.82-8.81). There was also independent relationship between the number of parity and RV hypertrophy even after adjustment for several confounders.

CONCLUSION

Pregnancy-related physiological changes mostly resolve after delivery. This study about long-term effects of pregnancy on RV has demonstrated that there is a significant relation between the number of parity and either RV dilation or RV hypertrophy. Each parity had also additive effect on these changes.

Pr-AKI: Acute Kidney Injury in Pregnancy – Etiology, Diagnostic Workup, Management

Despite significant improvements in inpatient and outpatient management, pregnancy-related acute kidney injury (Pr-AKI) remains an important risk factor for early and late maternal and fetal morbidity and mortality. There is a discrepancy between the incidence of Pr-AKI in developing and in developed countries, with the former experiencing a decrease and the latter an increase in Pr-AKI in recent decades. Whereas septic and hemorrhagic complications predominated in the past, nowadays hypertensive disorders and thrombotic microangiopathy are the leading causes of Pr-AKI. Modern lifestyles and the availability and widespread use of in-vitro fertilization techniques in industrialized countries have allowed more women of advanced age to become pregnant. This has led to a rise in the percentage of high-risk pregnancies due to the disorders and comorbidities inherent to or accompanying aging, such as diabetes, arterial hypertension and preexisting chronic kidney disease. Last but not least, the heterogeneity of symptoms, the often overlapping clinical and laboratory characteristics and the pathophysiological changes related to pregnancy make the diagnosis and management of Pr-AKI a difficult and challenging task for the treating physician. In addition to general supportive management strategies such as volume substitution, blood pressure control, prevention of seizures or immediate delivery, each disease entity requires a specific therapy to reduce maternal and fetal complications. In this review, we used the current literature to provide a summary of the physiologic and pathophysiologic changes in renal physiology which occur during pregnancy. In the second part, we present common and rare disorders which lead to Pr-AKI and provide an overview of the available treatment options.

SARS- CoV-2 infection and oxidative stress in early-onset preeclampsia

SARS-CoV-2 causes coronavirus disease 2019 (COVID-19) also in pregnant women. Infection in pregnancy leads to maternal and placental functional alterations. Pregnant women with vascular defects such as preeclampsia show high susceptibility to SARS-CoV-2 infection by undefined mechanisms. Pregnant women infected with SARS-CoV-2 show higher rates of preterm birth and caesarean delivery, and their placentas show signs of vasculopathy and inflammation. It is still unclear whether the foetus is affected by the maternal infection with this virus and whether maternal infection associates with postnatal affections. The SARS-CoV-2 infection causes oxidative stress and activation of the immune system leading to cytokine storm and next tissue damage as seen in the lung. The angiotensin-converting-enzyme 2 expression is determinant for these alterations in the lung. Since this enzyme is expressed in the human placenta, SARS-CoV-2 could infect the placenta tissue, although reported to be of low frequency compared with maternal lung tissue. Early-onset preeclampsia (eoPE) shows higher expression of ADAM17 (a disintegrin and metalloproteinase 17) causing an imbalanced renin-angiotensin system and endothelial dysfunction. A similar mechanism seems to potentially account for SARS-CoV-2 infection. This review highlights the potentially common characteristics of pregnant women with eoPE with those with COVID-19. A better understanding of the mechanisms of SARS-CoV-2 infection and its impact on the placenta function is determinant since eoPE/COVID-19 association may result in maternal metabolic alterations that might lead to a potential worsening of the foetal programming of diseases in the neonate, young, and adult.

Aldosterone and renin concentrations were abnormally elevated in a cohort of normotensive pregnant women

BACKGROUND

During pregnancy, the renin-angiotensin-aldosterone system (RAAS) undergoes major changes to preserve normal blood pressure (BP) and placental blood flow and to ensure a good pregnancy outcome. Abnormal aldosterone-renin metabolism is a risk factor for arterial hypertension and cardiovascular risk, but its association with pathological conditions in pregnancy remains unknown. Moreover, potential biomarkers associated with these pathological conditions should be identified.

AIM

To study a cohort of normotensive pregnant women according to their serum aldosterone and plasma renin levels and assay their small extracellular vesicles (sEVs) and a specific protein cargo (LCN2, AT1R).

METHODS

A cohort of 54 normotensive pregnant women at term gestation was included. We determined the BP, serum aldosterone, and plasma renin concentrations. In a subgroup, we isolated their plasma sEVs and semiquantitated two EV proteins (AT1R and LCN2).

RESULTS

We set a normal range of aldosterone and renin based on the interquartile range. We identified 5/54 (9%) pregnant women with elevated aldosterone and low renin levels and 5/54 (9%) other pregnant women with low aldosterone and elevated renin levels. No differences were found in sEV-LCN2 or sEV-AT1R.

CONCLUSION

We found that 18% of normotensive pregnant women had either high aldosterone or high renin levels, suggesting a subclinical status similar to primary aldosteronism or hyperreninemia, respectively. Both could evolve to pathological conditions by affecting the maternal vascular and renal physiology and further the BP. sEVs and their specific cargo should be further studied to clarify their role as potential biomarkers of RAAS alterations in pregnant women.

Regulation of the Placental Renin-Angiotensin-Aldosterone System in Early- and Late-Onset Preeclampsia

Preeclampsia (PE) is one of the most dangerous complications of pregnancy, characterized by hypertension, proteinuria, and symptoms of multiple organ failure, which are detected de novo after 20 weeks of pregnancy. The renin-angiotensin-aldosterone system (RAAS) is one of the first to recognize pregnancy and is an important regulator of blood pressure. The placenta has its own RAAS, the role of which in the development of PE is not fully understood. In this work, for the first time, we characterized the expression of RAAS components and miRNAs controlling it in the placenta at various times of PE manifestation. The data obtained will allow the development of a new strategy in the future for the search for therapeutic agents for patients suffering from PE and cardiovascular diseases.

Physiological and pathological roles of Ang II and Ang- (1-7) in the female reproductive system

The local Renin-Angiotensin System (RAS) has been demonstrated to exist in a wide range of tissues and organs, In the female reproductive system, it is mainly found in the ovary, uterus and placenta. The RAS system is made up of a series of active substances and enzymes, in addition to the circulating endocrine renin-angiotensin system. The active peptides Angiotensin II (Ang II) and Angiotensin (1-7) (Ang-(1-7)), in particular, appear to have distinct activities in the local RAS system, which also controls blood pressure and electrolytes. Therefore, in addition to these features, angiotensin and its receptors in the reproductive system seemingly get involved in reproductive processes, such as follicle growth and development, as well as physiological functions of the placenta and uterus. In addition, changes in local RAS components may induce reproductive diseases as well as pathological states such as cancer. In most tissues, Ang II and Ang- (1-7) seem to maintain antagonistic effects, but this conclusion is not always true in the reproductive system, where they play similar functions in some physiological and pathological roles. This review investigated how Ang II, Ang- (1-7) and their receptors were expressed, localized, and active in the female reproductive system. This review also summarized their effects on follicle development, uterine and placental physiological functions. The changes of local RAS components in a series of reproductive system diseases including infertility related diseases and cancer and their influence on the occurrence and development of diseases were elucidated. This article reviews the physiological and pathological roles of Ang II and Ang- (1-7) in female reproductive system,a very intricate system of tissue factors that operate as agonists and antagonists was found. Besides, the development of novel therapeutic strategies targeting components of this system may be a research direction in future.

ACE2: a key modulator of the renin-angiotensin system and pregnancy

Angiotensin-converting enzyme 2 (ACE2) is a membrane-bound protein containing 805 amino acids. ACE2 shows approximately 42% sequence similarity to somatic ACE but has different biochemical activities. The key role of ACE2 is to catalyze the vasoconstrictor peptide angiotensin (ANG) II to Ang-(1–7), thus regulating the two major counterbalancing pathways of the renin-angiotensin system (RAS). In this way, ACE2 plays a protective role in end-organ damage by protecting tissues from the proinflammatory actions of ANG II. The circulating RAS is activated in normal pregnancy and is essential for maintaining fluid and electrolyte homeostasis and blood pressure. Renin-angiotensin systems are also found in the conceptus. In this review, we summarize the current knowledge on the regulation and function of circulating and uteroplacental ACE2 in uncomplicated and complicated pregnancies, including those affected by preeclampsia and fetal growth restriction. Since ACE2 is the receptor for SARS-CoV-2, and COVID-19 in pregnancy is associated with more severe disease and increased risk of abnormal pregnancy outcomes, we also discuss the role of ACE2 in mediating some of these adverse consequences. We propose that dysregulation of ACE2 plays a critical role in the development of preeclampsia, fetal growth restriction, and COVID-19-associated pregnancy pathologies and suggest that human recombinant soluble ACE2 could be a novel therapeutic to treat and/or prevent these pregnancy complications.

The Importance of Cardiovascular Risk Assessment and Pregnancy Heart Team in the Management of Cardiovascular Disease in Pregnancy

Pregnancy-related maternal morbidity and mortality is increasing because of complications from cardiovascular disease. Pregnancy results in physiologic changes that can adversely impact the cardiovascular system and lead to adverse pregnancy outcomes. A multidisciplinary pregnancy heart team is essential to safely navigate women with heart disease through pregnancy. This role of the pregnancy heart team is to offer preconception counseling, determine pregnancy risks and educate women about those risks, develop a comprehensive antenatal and delivery plan, and ensure appropriate postpartum follow-up. These steps are important to improve cardiovascular outcomes in pregnancy.

Immunological and physiopathological approach of COVID-19 in pregnancy

Coronavirus disease-2019 (COVID-19) related to Coronavirus-2 (SARS-CoV-2) is a worldwide health concern. Despite the majority of patients will evolve asymptomatic or mild-moderate upper respiratory tract infections, 20% will develop severe disease. Based on current pathogenetic knowledge, a severe COVID-19 form is mainly a hyperinflammatory, immune-mediated disorder, triggered by a viral infection. Due to their particular immunological features, pregnant women are supposed to be particularly susceptible to complicate by intracellular infections as well as immunological disturbances. As an example, immune-thrombosis has been identified as a common immune-mediated and pathogenic phenomenon both in COVID-19, in obstetric diseases and in COVID-19 pregnant women. According to extensive published clinical data, is rationale to expect an interference with the normal development of pregnancy in selected SARS-CoV-2-infected cases, mainly during third trimester.This manuscript provides insights of research to elucidate the potential harmful responses to SARS-CoV-2 and /or other coronavirus infections, as well as bidirectional interactions between COVID-19 and pregnancy to improve their respective management.

The Angiotensin-converting Enzyme Insertion/Deletion Polymorphism as a Common Risk Factor for Major Pregnancy Complications

Idiopathic pregnancy complications pose a major threat to both maternal and fetal health worldwide. Numerous studies have implicated the role of the renin-angiotensin system (RAS) in the development of obstetric syndromes, since it is crucial for the uteroplacental function. A major RAS component is the angiotensin-converting enzyme (ACE), which hydrolyses angiotensin I to angiotensin II, and not only regulates arterial pressure, but also fibrinolytic activity, indirectly, through the expression of plasminogen activator inhibitor-1. A key functional polymorphism of the ACE gene is the insertion/deletion (I/D) polymorphism, which affects gene expression and product levels, and can therefore lead to high blood pressure and/or reduced fibrinolytic activity. These can cause major pregnancy complications, such as preeclampsia, recurrent pregnancy loss and preterm birth. This review discusses how the ACE I/D is associated with susceptibility towards pregnancy complications, on its own or in combination with other functional gene polymorphisms such, as the angiotensin II receptor type 1 (AT1R) A1166CC, angiotensin II receptor type 2 (AT2R) G1332A, plasminogen activator inhibitor-1 (PAI-1) 4G/5G, matrix metallopeptidase-9 (MMP-9) C1562T, angiotensinogen (AGT) M235T, renin (REN) 83A/G, factor XIII (F13) Val34Leu and endothelial nitric oxide synthase (eNOS) 4a/b.

SARS-CoV-2, Endothelial Dysfunction, and the Renin-Angiotensin System (RAS): A Potentially Dangerous Triad for the Development of Pre-Eclampsia

SARS-CoV-2 represents the greatest epidemiological, clinical, and social challenge the human being has had to face in this century. SARS-CoV-2 is not merely a respiratory virus, as its target cells range from upper airway respiratory cells to pulmonary cells but also and above all to the cardiovascular cells, such as pericytes and endothelial cells. Indeed, the pathology related to SARS-CoV-2, COVID-19, may be defined as a thromboinflammatory syndrome in its most severe form, characterized by sepsis-induced coagulopathy (SIC) and disseminated intravascular coagulopathy (DIC), which is prevalent in individuals already presenting a chronic level of inflammation (e.g., obese individuals, elderly) and hypertension. Pregnancy is not only an inflammatory-prone condition but is characterized by a consistent rearrangement of the blood circulation and coagulation profile. Cardiac output increases while arterial systolic and diastolic pressure decrease, regardless of the activation of the RAS system. ACE2, the SARS-CoV-2 entry receptor into the host cells, which transforms Ang II in Ang 1–7, is highly expressed in endothelial, smooth muscle cells and pericytes of placental villi, regulating blood pressure and fetal development. Pre-eclampsia is a pregnancy disorder characterized by hypertension and low levels of ACE2, endothelial dysfunction, and a high production of pro-inflammatory cytokines, resembling COVID-19 manifestations. Whereas pre-eclampsia and COVID-19 have overlapping clinical features, a role for SARS-CoV-2 as a leading cause of pre-eclampsia in COVID-19 positive pregnant women has not been clarified yet. In this mini-review, we will explore the possibility of the existence of such a link, focusing on the role of endothelial dysfunction and RAS in both pre-eclampsia and SARS-CoV-2-induced COVID-19 pathogenesis.

The (pro)renin receptor ((P)RR) and soluble (pro)renin receptor (s(P)RR) in pregnancy

The (pro)renin receptor ((P)RR) is a multi-functional protein that can be proteolytically cleaved and released in a soluble form (s(P)RR). Recently, the (P)RR and s(P)RR have become of interest in pregnancy and its associated pathologies. This is because the (P)RR not only activates tissue renin angiotensin systems, but it is also an integral component of vacuolar-ATPase, activates the wingless/integrated (Wnt)/β-catenin and extracellular signal regulated kinases 1 and 2/mitogen-activated protein kinase signalling pathways, and stabilises the β subunit of pyruvate dehydrogenase. Additionally, s(P)RR is detected in plasma and urine, and maternal plasma levels are elevated in pregnancy complications including fetal growth restriction, preeclampsia and gestational diabetes mellitus. Therefore, s(P)RR has potential as a biomarker for these pregnancy pathologies. Preliminary functional findings suggest that s(P)RR may be important for regulating fluid balance, inflammation and blood pressure, all of which contribute to a successful pregnancy. The (P)RR and s(P)RR regulate pathways that are known to be important in maintaining pregnancy, however their role in the physiological context of pregnancy is poorly characterised. This review summarises the known and potential functions of the (P)RR and s(P)RR in pregnancy, and how their dysregulation may contribute to pregnancy complications. It also highlights the need for further research into the source and function of s(P)RR in pregnancy. Soluble (P)RR levels could be indicative of placental, kidney or liver dysfunction and therefore be a novel clinical biomarker, or therapeutic target, to improve the detection and treatment of pregnancy pathologies.

The Prevalence Of Specific Gene Polymorphisms Related To Thrombophilia In Egyptian Women With Recurrent Pregnancy Loss

Background:

Despite the enhanced progress in identifying a number of leading causes to fetal miscarriage, still some women suffer from recurrent pregnancy loss (RPL) for unknown cause. A hidden genetic influence of coexisting hereditary thrombophilia was assumed to have a role.

Aim:

The aim was to investigate the association between unexplained RPL and thrombophilic gene variants of angiotensin I-converting enzyme (ACE) (rs4646994) and β-fibrinogen (rs1800790) genes.

Settings and Design:

The present case–control study was conducted on unexplained RPL in eighty women and eighty matched controls with no history of previous pregnancy loss.

Materials and Methods:

Analysis of extracted DNA was performed using polymerase chain reaction-restriction fragment length polymorphism method.

Statistical Analysis:

The frequency of genotypes and alleles was compared between groups using Chi-square test or Fisher's exact test. Risk assessment was made by odds ratio (OR) at a 95% confidence interval (CI).

Results:

Women with RPL group had higher frequency of DD than controls (47.5%, 31.25%, respectively, P = 0.086). D allele frequency was 0.67 and 0.54 in the control (P = 0.022). D allele carriers were at higher risk of RPL than the control as OR was 1.694 at 95% CI from 1.08 to 2.67. There was no association between the rs1800790 variant of β-fibrinogen gene and RPL.

Conclusion:

Females who are carriers for D allele of ACE I/D gene polymorphism are more liable to suffer from RPL. Screening for hereditary thrombophilia in females who are planning to conceive and have a history of RPL of unidentified cause is of great value to provide proper management and genetic counseling to high-risk couples.

Maternal Angiotensin Increases Placental Leptin in Early Gestation via an Alternative Renin-Angiotensin System Pathway: Suggesting a Link to Preeclampsia

[Figure: see text].

Bradykinin Exerts Independent Effects on Trophoblast Invasion and Blood Pressure in Pregnant Guinea Pigs

INTRODUCTION

The pleiotropic kininogen-kallikrein-kinin system is upregulated in pregnancy and localizes in the uteroplacental unit. To identify the systemic and local participation of the bradykinin type 2 receptor (B2R), this was antagonized by Bradyzide (BDZ) during 2 periods: from days 20 to 34 and from days 20 to 60 in pregnant guinea pigs.

METHODS

Pregnant guinea pigs received subcutaneous infusions of saline or BDZ from gestational day 20 until sacrifice on day 34 (Short B2R Antagonism [SH-B2RA]) or on day 60 (Prolonged B2R Antagonism [PR-B2RA]). In SH-BDZA, systolic blood pressure was determined on day 34, while in PR-BDZA it was measured preconceptionally, at days 40 and 60. On gestational day 60, plasma creatinine, uricemia, proteinuria, fetal, placental and maternal kidney weight, and the extent of trophoblast invasion were evaluated.

RESULTS

The SH-B2RA increased systolic blood pressure on day 34 and reduced trophoblast myometrial invasion, spiral artery remodeling, and placental sufficiency. The PR-B2RA suppressed the normal blood pressure fall observed on days 40 and 60; vascular transformation, placental efficiency, urinary protein, serum creatinine, and uric acid did not differ between the groups. The proportion of all studied mothers with lost fetuses was greater under BDZ infusion than in controls.

CONCLUSION

The increased systolic blood pressure and transient reduction in trophoblast invasion and fetal/placental weight in the SH-B2R blockade and the isolated impact on blood pressure in the PR-B2R blockade indicate that bradykinin independently modulates systemic hemodynamics and the uteroplacental unit through cognate vascular and local B2R receptors.

Hypertensive Disorders of Pregnancy

Hypertension is the most common medical disorder occurring during pregnancy and a leading cause of maternal and perinatal morbidity and mortality. Accurate blood pressure measurement and the diagnosis and treatment of hypertensive disorders during pregnancy and in the postpartum period are pivotal to improve outcomes. This article details hemodynamic adaptations to pregnancy and provides an approach to the prevention, diagnosis, and management of hypertensive disorders of pregnancy (HDP) and hypertensive emergencies. In addition, it reviews optimal strategies for the care of women with hypertension during the fourth trimester and beyond to minimize future cardiovascular risk.

Angiotensin Converting Enzyme 2 (ACE2) in Pregnancy: Preeclampsia and Small for Gestational Age

Introduction

An imbalance in angiotensin (Ang) peptides could contribute to the pathophysiology of preeclampsia (PE) and poor fetal growth.

Methods

We measured maternal plasma levels of Ang peptides and converting enzymes in non-pregnant women (n = 10), in normal pregnant women (n = 59), women delivering small for gestational age babies (SGA, n = 25) across gestation (13–36 weeks) and in women with PE (n = 14) in their third trimester.

Results

Plasma ACE, ACE2, and Ang-(1-7) levels, and ACE2 activity were significantly higher in normal pregnant women compared with non-pregnant women; neprilysin (NEP) levels were not changed. In SGA pregnancies, ACE and ACE2 levels were higher in early-mid pregnancy compared with normal pregnant women. In women with PE, plasma ACE, ACE2, NEP, and Ang-(1-7) levels and ACE2 activity were lower than levels in normal pregnant women.

Conclusion

The higher plasma ACE2 levels and activity in pregnancy could be driving the higher Ang-(1-7) levels. The early gestation increases in ACE and ACE2 levels in SGA pregnancies highlights the possibility that these enzymes could be used as potential early biomarkers of poor fetal growth. In women with PE, the reduced ACE2 and NEP levels at term, could be contributing to the reduction in Ang-(1-7) levels. These findings suggest that dysfunctional relationships between two key enzymes in the circulating RAS are involved in the pathogenesis of PE and SGA. Since soluble ACE2 can prevent binding of the novel coronavirus, SARS-CoV-2, to membrane bound ACE2, the interplay between ACE2 and the coronavirus and its impact in pregnancy requires further investigation.

Aldosterone from endometrial glands is benefit for human decidualization

Local renin-angiotensin system (RAS) in female reproductive system is involved in many physiological and pathological processes, such as follicular development, ovarian angiogenesis, ovarian, and endometrial cancer progress. However, studies on the functional relevance of RAS in human endometrium are limited, especially for renin-angiotensin-aldosterone system (RAAS). In this study, we defined the location of RAS components in human endometrium. We found that angiotensin II type-1 receptor (AT₁R) and aldosterone synthase (CYP11B2), major components of RAAS, are specifically expressed in endometrial gland during mid-secretory phase. Aldosterone receptor, mineralocorticoid receptor (MR), is elevated in stroma in mid-secretory endometrium. In vitro, MR is also activated by aldosterone during decidualization. Activated MR initiates LKB1 expression, followed by phosphorylating of AMPK that stimulates PDK4 expression. The impact of PDK4 on decidualization is independent on PDHE1α inactivation. Based on co-immunoprecipitation, PDK4 interacts with p-CREB to prevent its ubiquitination for facilitating decidualization via FOXO1. Restrain of MR activation interrupts LKB1/p-AMPK/PDK4/p-CREB/FOXO1 pathway induced by aldosterone, indicating that aldosterone action on decidualization is mainly dependent on MR stimulation. Aldosterone biosynthesized in endometrial gland during mid-secretory phase promotes decidualization via activating MR/LKB1/p-AMPK/PDK4/p-CREB/FOXO1 signaling pathway. This study provides the valuable information for understanding the underlying mechanism during decidualization.

The reproductive stress hypothesis

In this paper, we propose the reproductive stress hypothesis that describes the pregnant females response to reproductive events based upon the activation of the hypothalamic–pituitary–adrenal axis and sympathetic adrenomedullary system. The main components of the reproductive stress hypothesis can be summarized as follows: (1) events unique to reproduction including empathema, pregnancy, parturition and lactation cause non-specific responses in females, called active reproductive stress; (2) the fetus is a special stressor for pregnant females where endocrine hormones, including corticotropin-releasing hormones and fetal glucocorticoids secreted by the fetus and placenta, enter the maternal circulatory system, leading to another stress response referred to as passive reproductive stress and (3) response to uterine tension and intrauterine infection is the third type of stress, called fetal intrauterine stress. Appropriate reproductive stress is a crucial prerequisite in normal reproductive processes. By contrast, excessive or inappropriate reproductive stress may result in dysfunctions of the reproductive system, such as compromised immune function, leading to susceptibility to disease. The novel insights of the reproductive stress hypothesis have important implications for deciphering the pathogenesis of certain diseases in pregnant animals, including humans, which in turn may be applied to preventing and treating their occurrence.

Longitudinal study of angiotensin peptides in normal and pre-eclamptic pregnancy

PURPOSE

To address whether differential regulation of the renin-angiotensin-aldosterone system occurs in pre-eclampsia, we performed an analysis of the time course of circulating and urinary profiles of the vasoconstrictor (Ang II) and the vasodilator [Ang-(1-7)] peptides in normal pregnant (NP) and pre-eclamptic (PE) women.

METHODS

Urine and plasma samples from 86 nulliparous women were collected prospectively; 67 subjects continued as NP and 19 developed PE. Subjects were enrolled prior to 12 weeks of gestation and plasma and spot urine samples were obtained throughout gestation. Control samples were obtained at 6 weeks postpartum (PP).

RESULTS

Mean blood pressure (p < 0.001) was elevated at 31-37 weeks of gestation in PE subjects as compared with NP subjects. Plasma Ang I and Ang II levels were elevated in NP subjects as early as 16 weeks of gestation and maintained throughout gestation. In PE subjects both plasma Ang I and Ang II were elevated at 16-33 weeks as compared with PP levels. PE subjects showed reduced plasma Ang I and Ang II (at 35-37 weeks of gestation) compared with NP subjects. Plasma Ang-(1-7) was unchanged in both groups. All three urinary peptides increased throughout gestation in NP subjects. In PE subjects urinary Ang I was increased at 23-26 weeks and was maintained throughout gestation. Urinary Ang II was increased at 27-29 and 31-33 weeks of gestation. PE subjects had no change in urinary Ang-(1-7).

CONCLUSION

The activation of the RAS, particularly Ang II throughout normal gestation may contribute to the maintenance of vascular tone during normal pregnancy. However higher sensitivity to Ang II in pre-eclampsia may be potentiated by the higher circulating and urinary levels of Ang II, unopposed by local renal Ang-(1-7), and thus may contribute to the development of pre-eclampsia.