Gender and the renin-angiotensin-aldosterone system

Chronic Use of Antihypertensive Medications and Peak Exercise Blood Pressure in Adult Men and Women from the BALL ST Cohort

PURPOSE

To determine if individuals chronically (>1 yr) prescribed antihypertensive medications have a normal BP response to peak exercise compared with unmedicated individuals.

METHODS

Participants included 2555 adults from the Ball State Adult Fitness Longitudinal Lifestyle STudy cohort who performed a peak treadmill exercise test. Participants were divided into groups by sex and antihypertensive medication status. Individuals prescribed antihypertensive medications for >1 yr were included. Exaggerated and blunted SBP within each group was categorized using the Fitness Registry and the Importance of Exercise: A National Database (FRIEND) and absolute criteria as noted by the American Heart Association.

RESULTS

The unmedicated group had a greater prevalence ( P < 0.05) of blunted SBP responses, whereas the medicated group had a higher prevalence ( P < 0.05) of exaggerated SBP responses using both the FRIEND and absolute criteria. Peak SBP was higher ( P < 0.01) in medicated compared with unmedicated participants in the overall cohort when controlling for age and sex, but not after controlling for resting SBP ( P = 0.613), risk factors ( P = 0.104), or cardiorespiratory fitness ( P = 0.191). When men and women were assessed independently, peak SBP remained higher in the medicated women after controlling for age and resting SBP ( P = 0.039), but not for men ( P = 0.311). Individuals on beta-blockers had a higher peak SBP even after controlling for age, sex, risk factors, and cardiorespiratory fitness ( P = 0.022).

CONCLUSIONS

Individuals on antihypertensive medications have a higher peak SBP response to exercise. Given the prognostic value of exaggerated peak SBP, control of exercise BP should be considered in routine BP assessment and in the treatment of hypertension.

Association between systemic inflammation markers and blood pressure among children and adolescents: National Health and Nutrition Examination Survey

BACKGROUND

Few studies have estimated the associations of systemic inflammation markers and high blood pressure (HBP) in the pediatric population.

METHODS

Basing on data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018, we assessed the associations between four inflammation-related factors based on blood cell counts: systemic immune inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and risk for pediatric HBP by estimating odds ratios (ORs) using multivariable logistic regression models.

RESULTS

A total of 17,936 children aged 8-19 years were included in the analysis, representing about 36.7 million American children. The prevalence rates of elevated blood pressure (EBP) and hypertension (HTN) were 15.79% and 6.77%, respectively. The results showed that the ORs for EBP per standard deviation (SD) increment in SII and NLR were estimated at 1.11 [95% confidence interval (95%CI): 1.04, 1.17] and 1.08 (95%CI: 1.02, 1.15), respectively; and the OR for EBP per SD increment in LMP were estimated at 0.90 (95%CI: 0.83, 0.96). These associations were stronger in boys and younger children.

CONCLUSIONS

The study suggested that inflammation-related factors could serve as easily accessible early biomarkers for HBP risk prediction and prevention in children and adolescents.

IMPACT

The study suggested that inflammation-related factors could serve as easily accessible early biomarkers for HBP risk prediction and prevention in children and adolescents. This is the first study that demonstrates the close association between systemic inflammation markers and HBP in children and adolescents using nationally representative population data. The findings have more public health implications and support that systemic inflammation markers based on blood cell counts could serve as easily accessible biomarkers of HBP risk and prevention in earlier identification of the diseases.

The effect of 30 min of supine rest on plasma renin concentrations in paediatric patients

AIM

The aim of this study is to interpret plasma renin concentrations (PRCs) correctly in a clinical setting, it is essential to understand to what extent physical activity influences the concentration. Reference values for different postural positions exist for adults, but data for children are sparse. In this study, the effect of 30 min of rest on plasma renin concentrations in paediatric patients was examined.

METHODS

In total, 41 paediatric patients, undergoing either arginine or clonidine provocation tests for growth hormone deficiency, were included. For each stimulation test, two blood samples were drawn. One at time 0 min and one after 30 min of rest. In total, renin concentrations were determined in 86 serum samples.

RESULTS

Renin concentrations decreased from 0 to 30 min with a median value of -20.5% (inter-quartile range: -33.0% to -12.8%). This decrease was not dependent on sex, age, medication or comorbidity, and the variance of renin did not differ between 0 and 30 min.

CONCLUSION

Renin concentrations in children differ according to postural position, which is comparable to adults. Thus, the clinical interpretation of renin results needs to consider the preanalytical conditions applied in the local reference population.

Commensal microbiota regulate aldosterone

The gut microbiome regulates many important host physiological processes associated with cardiovascular health and disease; however, the impact of the gut microbiome on aldosterone is unclear. Investigating whether gut microbiota regulate aldosterone can offer novel insights into how the microbiome affects blood pressure. In this study, we aimed to determine whether gut microbiota regulate host aldosterone. We used enzyme-linked immunosorbent assays (ELISAs) to assess plasma aldosterone and plasma renin activity (PRA) in female and male mice in which gut microbiota are intact, suppressed, or absent. In addition, we examined urinary aldosterone. Our findings demonstrated that when the gut microbiota is suppressed following antibiotic treatment, there is an increase in plasma and urinary aldosterone in both female and male mice. In contrast, an increase in PRA is seen only in males. We also found that when gut microbiota are absent (germ-free mice), plasma aldosterone is significantly increased compared with conventional animals (in both females and males), but PRA is not. Understanding how gut microbiota influence aldosterone levels could provide valuable insights into the development and treatment of hypertension and/or primary aldosteronism. This knowledge may open new avenues for therapeutic interventions, such as probiotics or dietary modifications to help regulate blood pressure via microbiota-based changes to aldosterone.NEW & NOTEWORTHY We explore the role of the gut microbiome in regulating aldosterone, a hormone closely linked to blood pressure and cardiovascular disease. Despite the recognized importance of the gut microbiome in host physiology, the relationship with circulating aldosterone remains largely unexplored. We demonstrate that suppression of gut microbiota leads to increased levels of plasma and urinary aldosterone. These findings underscore the potential of the gut microbiota to influence aldosterone regulation, suggesting new possibilities for treating hypertension.

Nocturia in Menopausal Women: The Link Between Two Common Problems of the Middle Age

INTRODUCTION AND HYPOTHESIS

The aim of this review is to discuss the link between menopause and nocturia and to give an overview of the increasing prevalence, risk factors, causative factors, treatment needs and options for nocturia in peri-menopausal women.

METHODS

This opinion article is a narrative review based on the expertise and consensus of a variety of key opinion leaders, in combination with an extensive literature review. This literature search included a thorough analysis of potential publications on both the PubMed Database and the Web of Science and was conducted between November 2022 and December 2022. The following key words were used "nocturia" and "menopause" or "nocturnal frequency and menopause." Moreover, key words including "incidence," "prevalence," "insomnia," "estrogen therapy," "metabolic syndrome," and "hot flushes" were used in combination with the aforementioned key words. Last, the reference lists of articles obtained were screened for other relevant literature.

RESULTS

The perimenopause can be a trigger for inducing nocturia. Typically, obesity, body mass index (BMI), and waist circumference are risk factors for developing peri-menopausal nocturia. Presumably the development of peri-menopausal nocturia is multifactorial, with interplay among bladder, sleep, and kidney problems due to estrogen depletion after the menopause. First, impaired stimulation of estrogen receptors in the urogenital region leads to vaginal atrophy and reduced bladder capacity. Moreover, menopause is associated with an increased incidence of overactive bladder syndrome. Second, estrogen deficiency can induce salt and water diuresis through blunted circadian rhythms for the secretion of antidiuretic hormone and the activation of the renin-angiotensin-aldosterone system. Additionally, an increased incidence of sleep disorders, including vasomotor symptoms and obstructive sleep apnea signs, is observed. Oral dryness and a consequent higher fluid intake are common peri-menopausal symptoms. Higher insulin resistance and a higher risk of cardiovascular diseases may provoke nocturia. Given the impact of nocturia on general health and quality of life, bothersome nocturia should be treated. Initially, behavioral therapy should be advised. If these modifications are inadequate, specific treatment should be proposed. Systemic hormone replacement is found to have a beneficial effect on nocturia, without influencing sodium and water clearance in patients with nocturnal polyuria. It is presumed that the improvement in nocturia from hormonal treatment is due to an improvement in sleep disorders.

Predicting sex differences in the effects of diuretics in renal epithelial transport during angiotensin II-induced hypertension

Chronic angiotensin II (ANG II) infusion is an experimental model that induces hypertension in rodents. The natriuresis, diuresis, and blood pressure responses differ between males and females. This is perhaps not unexpected, given the rodent kidney, which plays a key role in blood pressure regulation, exhibits marked sex differences. Under normotensive conditions, compared with males, the female rat nephron exhibits lower Na+/H+ exchanger 3 (NHE3) activity along the proximal tubule but higher Na+ transporter activities along the distal segments. ANG II infusion-induced hypertension induces a pressure natriuretic response that reduces NHE3 activity and shifts Na+ transport capacity downstream. The goals of this study were to apply a computational model of epithelial transport along a rat nephron 1) to understand how a 14-day ANG II infusion impacts segmental electrolyte transport in male and female rat nephrons and 2) to identify and explain any sex differences in the effects of loop diuretics, thiazide diuretics, and K+-sparing diuretics. Model simulations suggest that the NHE3 downregulation in the proximal tubule is a major contributor to natriuresis and diuresis in hypertension, with the effects stronger in males. All three diuretics are predicted to induce stronger natriuretic and diuretic effects under hypertension compared with normotension, with relative increases in sodium excretion higher in hypertensive females than in males. The stronger natriuretic responses can be explained by the downstream shift of Na+ transport load in hypertension and by the larger distal transport load in females, both of which limit the ability of the distal segments to further elevate their Na+ transport.NEW & NOTEWORTHY Sex differences in the prevalence of hypertension are found in human and animal models. The kidney, which regulates blood pressure, exhibits sex differences in morphology, hemodynamics, and membrane transporter distributions. This computational modeling study provides insights into how the sexually dimorphic responses to a 14-day angiotensin II infusion differentially impact segmental electrolyte transport in rats. Simulations of diuretic administration explain how the natriuretic and diuretic effects differ between normotension and hypertension and between the sexes.

Italian Association of Hospital Cardiologists Position Paper 'Gender discrepancy: time to implement gender-based clinical management'

It has been well assessed that women have been widely under-represented in cardiovascular clinical trials. Moreover, a significant discrepancy in pharmacological and interventional strategies has been reported. Therefore, poor outcomes and more significant mortality have been shown in many diseases. Pharmacokinetic and pharmacodynamic differences in drug metabolism have also been described so that effectiveness could be different according to sex. However, awareness about the gender gap remains too scarce. Consequently, gender-specific guidelines are lacking, and the need for a sex-specific approach has become more evident in the last few years. This paper aims to evaluate different therapeutic approaches to managing the most common women's diseases.

Diverse biological functions of the renin-angiotensin system

The renin-angiotensin system (RAS) has been widely known as a circulating endocrine system involved in the control of blood pressure. However, components of RAS have been found to be localized in rather unexpected sites in the body including the kidneys, brain, bone marrow, immune cells, and reproductive system. These discoveries have led to steady, growing evidence of the existence of independent tissue RAS specific to several parts of the body. It is important to understand how RAS regulates these systems for a variety of reasons: It gives a better overall picture of human physiology, helps to understand and mitigate the unintended consequences of RAS-inhibiting or activating drugs, and sets the stage for potential new therapies for a variety of ailments. This review fulfills the need for an updated overview of knowledge about local tissue RAS in several bodily systems, including their components, functions, and medical implications.

Role of Female Sex Hormones in ADPKD Progression and a Personalized Approach to Contraception and Hormonal Therapy

This review navigates the intricate relationship between gender, hormonal influences, and the progression of autosomal dominant polycystic kidney disease (ADPKD), highlighting the limited literature on this crucial topic. The study explores the impact of female sex hormones on liver and renal manifestations, uncovering gender-specific differences in disease progression. Actually, hormonal therapy in women with ADPKD remains a challenging issue and is a source of concern regarding its potential impact on disease outcomes, particularly at the hepatic level. Notably, women with ADPKD exhibit a slower renal disease progression compared to men, attributed to hormonal dynamics. This review sheds light on the role of estrogen in regulating pathways of the renin-angiotensin-aldosterone system, revealing its complex interplay and implications for cardiovascular and renal health. Therapeutic considerations for fertile women with ADPKD, including contraception options, are discussed, emphasizing the necessity for personalized approaches. In the postmenopausal phase, the review evaluates the role of hormonal replacement therapy, considering its potential benefits and risks in the context of ADPKD. The review concludes by underscoring the imperative need for tailored treatment approaches for ADPKD patients, considering individual risks and benefits. The scarcity of literature underlines the call for further research to enhance our understanding of optimal hormonal therapies in the context of ADPKD, ultimately paving the way for innovative and personalized therapeutic interventions.

Sex influences blood pressure but not blood pressure variability in response to dietary sodium and potassium in salt-resistant adults

Dietary sodium and potassium have been shown to affect blood pressure (BP) but their influence on BP variability (BPV) is less studied as is the influence of sex. The aim of this study was to compare 24 h BP and short-term BPV in response to varying dietary levels of sodium and potassium in healthy non-obese normotensive salt-resistant adults. We hypothesized that high sodium would increase short-term BP and BPV while the addition of high potassium would counteract this increase. Furthermore, we hypothesized that women would experience greater increases in BPV under high sodium conditions compared to men while potassium would attenuate this response. Thirty-seven participants (17 M/20 W; 27 ± 5 years old; BMI 24.3 ± 3 kg/m2) completed seven days each of the following randomized diets: moderate potassium/low sodium (MK/LS), moderate potassium/high sodium (MK/HS) and high potassium/high sodium (HK/HS). BP and short-term BPV were assessed using 24 h ambulatory BP monitoring starting on day 6. BPV was calculated using the average real variability (ARV) index. Twenty-four hour, daytime, and nighttime systolic BP (SBP) were lower in women compared to men regardless of diet. However, 24 h and daytime SBP were lowered in women on the HK/HS diet compared to the MK/HS diet. There were no significant effects of diet or sex for 24 h, daytime or nighttime SBP ARV. However, men exhibited a higher 24 hDBP ARV than women regardless of diet. In conclusion, a high potassium diet lowered BP under high sodium conditions in women alone while men exhibited higher short-term BPV that was not influenced by diet.

MicroRNA-19 is regulated by aldosterone in a sex-specific manner to alter kidney sodium transport

A key regulator of blood pressure homeostasis is the steroid hormone aldosterone, which is released as the final signaling hormone of the renin-angiotensin-aldosterone-signaling (RAAS) system. Aldosterone increases sodium (Na+) reabsorption in the kidney distal nephron to regulate blood volume. Unregulated RAAS signaling can lead to hypertension and cardiovascular disease. The serum and glucocorticoid kinase (SGK1) coordinates much of the Na+ reabsorption in the cortical collecting duct (CCD) tubular epithelial cells. We previously demonstrated that aldosterone alters the expression of microRNAs (miRs) in CCD principal cells. The aldosterone-regulated miRs can modulate Na+ transport and the cellular response to aldosterone signaling. However, the sex-specific regulation of miRs by aldosterone in the kidney distal nephron has not been explored. In this study, we report that miR-19, part of the miR-17-92 cluster, is upregulated in female mouse CCD cells in response to aldosterone activation. Mir-19 binding to the 3'-untranslated region of SGK1 was confirmed using a dual-luciferase reporter assay. Increasing miR-19 expression in CCD cells decreased SGK1 message and protein expression. Removal of this cluster using a nephron-specific, inducible knockout mouse model increased SGK1 expression in female mouse CCD cells. The miR-19-induced decrease in SGK1 protein expression reduced the response to aldosterone stimulation and may account for sex-specific differences in aldosterone signaling. By examining evolution of the miR-17-92 cluster, phylogenetic sequence analysis indicated that this cluster arose at the same time that other Na+-sparing and salt regulatory proteins, specifically SGK1, first emerged, indicating a conserved role for these miRs in kidney function of salt and water homeostasis.NEW & NOTEWORTHY Expression of the microRNA-17-92 cluster is upregulated by aldosterone in mouse cortical collecting duct principal cells, exclusively in female mice. MiR-19 in this cluster targets the serum and glucocorticoid kinase (SGK1) to downregulate both mRNA and protein expression, resulting in a decrease in sodium transport across epithelial cells of the collecting duct. The miR-17-92 cluster is evolutionarily conserved and may act as a novel feedback regulator for aldosterone signaling in females.

Aromatase enzyme: Paving the way for exploring aromatization for cardio-renal protection

Documented male-female differences in the risk of cardiovascular and chronic kidney diseases have been largely attributed to estrogens. The cardiovascular and renal protective effects of estrogens are mediated via the activation of estrogen receptors (ERα and ERβ) and G protein-coupled estrogen receptor, and involve interactions with the renin-angiotensin-aldosterone system. Aromatase, also called estrogen synthase, is a cytochrome P-450 enzyme that plays a pivotal role in the conversion of androgens into estrogens. Estrogens are biosynthesized in gonadal and extra-gonadal sites by the action of aromatase. Evidence suggests that aromatase inhibitors, which are used to treat high estrogen-related pathologies, are associated with the development of cardiovascular events. We review the potential role of aromatization in providing cardio-renal protection and highlight several meta-analysis studies on cardiovascular events associated with aromatase inhibitors. Overall, we present the potential of aromatase enzyme as a fundamental contributor to cardio-renal protection.

Effects of Gender and Vitamin D on Vascular Reactivity of the Carotid Artery on a Testosterone-Induced PCOS Model

The negative cardiovascular effects of polycystic ovary syndrome (PCOS) and vitamin D deficiency (VDD) have been discussed previously; however, the sex differences between PCOS females and males are not yet known. Our aim was to investigate the effect of PCOS and VDD in the carotid artery of male and female Wistar rats. Females were treated with transdermal testosterone (Androgel) for 8 weeks, which caused PCOS. VDD and vitamin D supplementation were accomplished via diet. The carotid arteries' contraction and relaxation were examined using myography. Receptor density was investigated using immunohistochemistry. In PCOS females, angiotensin receptor density, angiotensin II-induced contraction, androgen receptor optical density, and testosterone-induced relaxation increased. The increased contractile response may increase cardiovascular vulnerability in women with PCOS. As an effect of VDD, estrogen receptor density increased in all our groups, which probably compensated for the reduced relaxation caused by VDD. Testosterone-induced relaxation was decreased as a result of VDD in males and non-PCOS females, whereas this reduction was absent in PCOS females. Male sex is associated with increased contraction ability compared with non-PCOS and PCOS females. VDD and Androgel treatment show significant gender differences in their effects on carotid artery reactivity. Both VDD and PCOS result in a dysfunctional vascular response, which can contribute to cardiovascular diseases.

Estrogen-induced signalling and the renal contribution to salt and water homeostasis

The kidney is considered to be one of the most estrogen-responsive, not reproductive organs in the body. Different estrogen receptors (ERs) show sex-specific differences in expression along the nephron and the expression of different ERs also changes with the estrous cycle of the female. The kidney becomes more estrogen-sensitive when estradiol levels are at their highest, just prior to ovulation. This review discusses the different mechanisms by which estradiol can modify the salt and water conservation processes of the kidney through transporter regulation to support the fluid and electrolyte homeostasis changes required in mammalian reproduction. The kidney plays a critical role in regulating blood pressure by controlling fluid homeostasis, and so protects the female cardiovascular system from dramatic changes in whole body fluid volume that occur at critical points in the human menstrual cycle and in pregnancy. This is augmented by the direct actions of estradiol on the cardiovascular system, for example through the direct stimulation of endothelial nitric oxide (NO) synthase, which releases NO to promote vasodilation. This and other mechanisms are less evident in the male and give women a degree of cardiovascular protection up until menopause, when the risks of cardiovascular disease and chronic kidney disease begin to match the risks experienced by males.

Associations Between Aldosterone-Renin-Ratio and Bone Parameters Derived from Peripheral Quantitative Computed Tomography and Impact Microindentation in Men

Components of the renin-angiotensin-aldosterone system (RAAS) are present on bone cells. One measure of RAAS activity, the aldosterone-renin-ratio (ARR), is used to screen for primary aldosteronism. Associations between ARR and bone mineral density are conflicting. This study investigated associations between ARR and peripheral quantitative computed tomography (pQCT) and impact microindentation (IMI). Male participants (n = 431) were from the Geelong Osteoporosis Study. "Likely" primary aldosteronism was defined as ARR ≥ 70 pmol/mIU. Another group, "possible" primary aldosteronism, was defined as either ARR ≥ 70 pmol/mIU or taking a medication that affects the RAAS, but not a beta blocker, and renin < 15 mU/L. Using pQCT, images at 4% and 66% of radial (n = 365) and tibial (n = 356) length were obtained. Using IMI measurements, bone material strength index (BMSi; n = 332) was determined. Associations between ARR or likely/possible primary aldosteronism and IMI or pQCT-derived bone parameters were tested using median regression. ARR and aldosterone values were not associated with any of the pQCT-derived bone variables in either unadjusted or adjusted analyses. Men with likely primary aldosteronism (n = 16), had lower adjusted total bone area (radial 66% site, - 12.5%). No associations were observed for men with possible primary aldosteronism (unadjusted or adjusted). No associations with BMSi were observed (p > 0.05). There were no associations between ARR or aldosterone and pQCT-derived bone parameters. Men with likely primary aldosteronism had lower bone area, suggesting clinically high levels of ARR may have a negative impact on bone health.

The Protective Pathways Activated in Kidneys of αMUPA Transgenic Mice Following Ischemia\Reperfusion-Induced Acute Kidney Injury

Despite the high prevalence of acute kidney injury (AKI), the therapeutic approaches for AKI are disappointing. This deficiency stems from the poor understanding of the pathogenesis of AKI. Recent studies demonstrate that αMUPA, alpha murine urokinase-type plasminogen activator (uPA) transgenic mice, display a cardioprotective pathway following myocardial ischemia. We hypothesize that these mice also possess protective renal pathways. Male and female αMUPA mice and their wild type were subjected to 30 min of bilateral ischemic AKI. Blood samples and kidneys were harvested 48 h following AKI for biomarkers of kidney function, renal injury, inflammatory response, and intracellular pathways sensing or responding to AKI. αMUPA mice, especially females, exhibited attenuated renal damage in response to AKI, as was evident from lower SCr and BUN, normal renal histology, and attenuated expression of NGAL and KIM-1. Notably, αMUPA females did not show a significant change in renal inflammatory and fibrotic markers following AKI as compared with wild-type (WT) mice and αMUPA males. Moreover, αMUPA female mice exhibited the lowest levels of renal apoptotic and autophagy markers during normal conditions and following AKI. αMUPA mice, especially the females, showed remarkable expression of PGC1α and eNOS following AKI. Furthermore, MUPA mice showed a significant elevation in renal leptin expression before and following AKI. Pretreatment of αMUPA with leptin-neutralizing antibodies prior to AKI abolished their resistance to AKI. Collectively, the kidneys of αMUPA mice, especially those of females, are less susceptible to ischemic I/R injury compared to WT mice, and this is due to nephroprotective actions mediated by the upregulation of leptin, eNOS, ACE2, and PGC1α along with impaired inflammatory, fibrotic, and autophagy processes.

The Renin Angiotensin System as a Therapeutic Target in Traumatic Brain Injury

Traumatic brain injury (TBI) is a major public health problem, with limited pharmacological options available beyond symptomatic relief. The renin angiotensin system (RAS) is primarily known as a systemic endocrine regulatory system, with major roles controlling blood pressure and fluid homeostasis. Drugs that target the RAS are used to treat hypertension, heart failure and kidney disorders. They have now been used chronically by millions of people and have a favorable safety profile. In addition to the systemic RAS, it is now appreciated that many different organ systems, including the brain, have their own local RAS. The major ligand of the classic RAS, Angiotensin II (Ang II) acts predominantly through the Ang II Type 1 receptor (AT1R), leading to vasoconstriction, inflammation, and heightened oxidative stress. These processes can exacerbate brain injuries. Ang II receptor blockers (ARBs) are AT1R antagonists. They have been shown in several preclinical studies to enhance recovery from TBI in rodents through improvements in molecular, cellular and behavioral correlates of injury. ARBs are now under consideration for clinical trials in TBI. Several different RAS peptides that signal through receptors distinct from the AT1R, are also potential therapeutic targets for TBI. The counter regulatory RAS pathway has actions that oppose those stimulated by AT1R signaling. This alternative pathway has many beneficial effects on cells in the central nervous system, bringing about vasodilation, and having anti-inflammatory and anti-oxidative stress actions. Stimulation of this pathway also has potential therapeutic value for the treatment of TBI. This comprehensive review will provide an overview of the various components of the RAS, with a focus on their direct relevance to TBI pathology. It will explore different therapeutic agents that modulate this system and assess their potential efficacy in treating TBI patients.

The associations between hematological parameters and the incidence of prehypertension and hypertension in children and adolescents: a prospective cohort study

Uncontrolled pediatric hypertension may increase the risk of hypertension in adulthood. Several studies have reported an association between hematological parameters and blood pressure (BP) levels. However, epidemiologic evidence of this association in children and adolescents remains scarce. This study aims to explore the associations between hematological parameters and the incidence of prehypertension and hypertension in children and adolescents. This longitudinal study was conducted with 1368 participants aged 6-8 years from baseline visit to follow-up visit. Compared with participants from the normal blood pressure (BP) group, participants from the elevated BP group had significantly higher baseline red blood cell (RBC) counts, hemoglobin (Hb) counts and hematocrit (Hct) levels (all P < 0.001). A multilevel linear mixed model was conducted to analyze the relationship between hematological parameters and BP levels. The results suggested that SBP, DBP and MAP increased significantly with a quartile increase of levels of hematological parameters (all P < 0.05). Furthermore, a multilevel mixed logistic regression model was used to analyze the risk of per interquartile range increase in hematological parameters on the incidence of prehypertension and hypertension. The risk of prehypertension and hypertension incidence increased by (1.34 (95%CIs: 1.20, 1.50)), (1.38 (95%CIs: 1.24,1.54)), (1.33 (95%CIs: 1.19,1.50)), (1.14 (95%CIs: 1.03,1.26)) fold with a one-quartile increase in levels of RBC, Hb, Hct and Fe, respectively (all P < 0.05). This longitudinal study showed that hematological parameters were positively associated with BP levels in healthy children and adolescents, which excluded the effect of antihypertensive drugs on BP levels that often appeared in adults.

Sexual Dimorphic Interplays Between Gut Microbiota and Antihypertensive Drugs

PURPOSE OF THE REVIEW

The purpose of this study is to review the current literature regarding gut microbiota in blood pressure regulation and its interactions with antihypertensive drugs and to discuss how sex differences in gut microbiota contribute to sexual dimorphism of hypertension and treatment.

RECENT FINDINGS

The significance of gut microbiota in blood pressure regulation and hypertension etiology is growingly recognized. Targeting the dysbiotic microbiota is proposed to be a new therapeutic method. Recently, a few studies demonstrated that the gut microbiota is highly involved in the modulation of the efficacy of antihypertensive drugs, suggesting a novel mechanism by which gut microbiota plays a role in treatment-resistant hypertension. Furthermore, studies on sex differences in gut microbiota, etiology of hypertension, and sex bias in prescription of antihypertensive medications have revealed promising avenues in sexual dimorphism-based precision medicine. However, no scientific questions are ever raised on how sex differences in gut microbiota contribute to the sex specific responses of certain classes of antihypertensive drugs. Given the dynamics and complexity among individuals, precision medicine is proposed of great potential. We review current knowledge on the interactions between gut microbiota, hypertension, and antihypertensive drugs with an emphasis on sex as a crucial determinant. We propose that sex differences in gut microbiota be a research focus to advance our understanding of hypertension management.

Sex Differences in the Anti-Hypertensive Effect of Calcium-Channel Blockers: A Systematic Review and Meta-Analysis

Cardiovascular disease (CVD) is the number one cause of death worldwide, with hypertension as the leading risk factor for both sexes. As sex may affect responsiveness to antihypertensive compounds, guidelines for CVD prevention might necessitate divergence between females and males. To this end, we studied the effectiveness of calcium channel blockers (CCB) on blood pressure (BP), heart rate (HR) and cardiac function between sexes. We performed a systematic review and meta-analysis on studies on CCB from inception to May 2020. Studies had to present both baseline and follow-up measurements of the outcome variables of interest and present data in a sex-stratified manner. Mean differences were calculated using a random-effects model. In total, 38 studies with 8202 participants were used for this review. In females as compared to males, systolic BP decreased by -27.6 mmHg (95%CI -36.4; -18.8) (-17.1% (95%CI -22.5;-11.6)) versus -14.4 mmHg (95%CI -19.0; -9.9) (-9.8% (95%CI -12.9;-6.7)) (between-sex difference p < 0.01), diastolic BP decreased by -14.1 (95%CI -18.8; -9.3) (-15.2%(95%CI -20.3;-10.1)) versus -10.6 mmHg (95%CI -14.0; -7.3) (-11.2% (95%CI -14.8;-7.7)) (between-sex difference p = 0.24). HR decreased by -1.8 bpm (95%CI -2.5; -1.2) (-2.5% (95%CI -3.4; -1.6)) in females compared to no change in males (0.3 bpm (95% CI -1.2; 1.8)) (between-sex difference p = 0.01). In conclusion, CCB lowers BP in both sexes, but the observed effect is larger in females as compared to males.

Multiomics Analyses Reveal Sex Differences in Mouse Renal Proximal Subsegments

SIGNIFICANCE STATEMENT

Sex-dependent differences in kidney function are recognized but the underlying molecular mechanisms are largely unexplored. Advances in genomics and proteomic technologies now allow extensive characterization of differences between the same cell types of males and females. Multiomics integrating RNA-seq, ATAC-seq, and proteomics data to investigate differences in gene expression, chromatin accessibility, and protein expression in proximal tubules of male and female mice identified many sex-biased genes and proteins associated with kidney functions, including metabolic and transport processes. Sex differences may also arise from variations of the interaction between transcription factors and accessible chromatin regions. A comprehensive web resource is provided to advance understanding of sex differences in cells of the proximal tubule.

BACKGROUND

Sex differences have been increasingly recognized as important in kidney physiology and pathophysiology, but limited resources are available for comprehensive interrogation of sex differences.

METHODS

RNA-seq and ATAC-seq of microdissected mouse proximal tubules and protein mass spectrometry of homogenized perfused mouse kidneys reveal differences in proximal tubule cells of males and females.

RESULTS

The transcriptomic data indicated that the major differences in the proximal tubules between the sexes were in the S2/S3 segments, and most of the sex-biased transcripts mapped to autosomes rather than to the sex chromosomes. Many of the transcripts exhibiting sex-biased expression are involved in monocarboxylic acid metabolic processes, organic anion transport, and organic acid transport. The ATAC-seq method on microdissected tubules captured chromatin accessibility. Many of the more than 7000 differentially accessible DNA regions identified were in distal regions. Motif analyses revealed a lack of direct involvement of estrogen receptors or the androgen receptor (absence of canonical hormone response elements), suggesting an indirect regulatory role of sex hormones. Instead, analyses identified several transcription factors (TFs) ( Tead1 , Nfia/b , and Pou3f3 ) whose interplay with proximal tubule-specific TFs ( e.g. , Hnf1b , Hnf4a ) may contribute to sex differences. Finally, the whole-kidney proteome was correlated with the transcriptome, and many sex-biased proteins ( e.g. , Cyp2e1, Acsm2/3) were identified.

CONCLUSIONS

Sex-dependent cis-regulatory elements interact with TFs in ways that lead to sex-biased gene expression in proximal tubule cells. These data are provided as a user-friendly web page at https://esbl.nhlbi.nih.gov/MRECA/PT/ .

Reorganization and Suppression of Store-Operated Calcium Entry in Podocytes of Type 2 Diabetic Rats

Type 2 diabetes mellitus (DM2) is a widespread metabolic disorder that results in podocyte damage and diabetic nephropathy. Previous studies demonstrated that TRPC6 channels play a pivotal role in podocyte function and their dysregulation is associated with development of different kidney diseases including nephropathy. Here, using single channel patch clamp technique, we demonstrated that non-selective cationic TRPC6 channels are sensitive to the Ca²⁺ store depletion in human podocyte cell line Ab8/13 and in freshly isolated rat glomerular podocytes. Ca²⁺ imaging indicated the involvement of ORAI and sodium-calcium exchanger in Ca²⁺ entry induced upon store depletion. In male rats fed a high-fat diet combined with a low-dose streptozotocin injection, which leads to DM2 development, we observed the reduction of a store-operated Ca²⁺ entry (SOCE) in rat glomerular podocytes. This was accompanied by a reorganization of store-operated Ca²⁺ influx such that TRPC6 channels lost their sensitivity to Ca²⁺ store depletion and ORAI-mediated Ca²⁺ entry was suppressed in TRPC6-independent manner. Altogether our data provide new insights into the mechanism of SOCE organization in podocytes in the norm and in pathology, which should be taken into account when developing pharmacological treatment of the early stages of diabetic nephropathy.

Reference intervals for LC-MS /MS measurements of plasma renin activity, aldosterone, angiotensin II, and 24-hour urinary aldosterone in Northern Chinese Han population

BACKGROUND

Examination of aldosterone to Renin Ratio (ARR) and plasma aldosterone concentration (PAC) or 24-h urinary aldosterone excretion (24-h UALD) was the necessary tests in confirmatory tests for primary aldosteronism (PA). We developed a combined liquid chromatography-tandem mass spectrometry method (LC-MS/MS) for plasma renin activity (PRA), PAC, and angiotensin II (Ang II) and investigated their reference intervals (RIs) in northern Chinese Han population. The RIs of 24-h UALD excretion were also studied using LC-MS/MS.

METHODS

A total of 309 healthy volunteers were recruited in 3 cities in China. PRA, PAC, Ang II, and 24-h UALD were measured using the laboratory-developed LC-MS/MS. Multiple linear regression and the variance component model were applied to determine if the RI needed to be split. The RIs of PRA, PAC, and Ang II were determined using the nonparametric percentile method.

RESULTS

The laboratory-developed LC-MS/MS method was verified and showed good performance. Standard deviation ratio (SDR) sex for PAC and SDR region for Ang II are 0.466 and 0.407, respectively, indicating that the RIs of PAC and Ang II must be divided by sex and region, respectively. In addition, the SDR 24hUK for 24-h UALD is 0.579, indicating that the RI of 24-h UALD must be partitioned by urine potassium.

CONCLUSION

RIs were established for tests related to the renin-angiotensin-aldosterone system in the apparently healthy northern Chinese Han population by the LC-MS/MS method.

Sex and gender differences in the treatment of arterial hypertension

INTRODUCTION

Arterial hypertension represents the leading modifiable risk factor for all-cause death and early development of cardiovascular disease in women. Current clinical guidelines for the treatment of hypertension noted that women respond to antihypertensive drugs similarly to men and, therefore, treatment recommendations remain the same for both sexes. However, clinical evidence suggests the existence of sex- and gender-related differences (SGRD) in the prevalence, pathophysiology, pharmacodynamics (efficacy and safety) and pharmacokinetics of antihypertensive drugs.

AREAS COVERED

This review summarizes SGRD in the prevalence of hypertension, hypertension-mediated organ damage and blood pressure control, prescription patterns, and pharmacokinetics/ pharmacodynamics and doses of antihypertensive drugs.

EXPERT OPINION

There is limited information on SGRD in antihypertensive drug efficacy because of the underrepresentation of women in randomized clinical trials and, more important, because few trials reported results stratified by sex or performed sex-specific analyses. However, there are SGRD in hypertension-mediated organ damage, drug pharmacokinetics and, particularly, in drug safety. Prospective trials specifically designed to better understand the basis for SGRD in the pathophysiology of hypertension and in the efficacy and safety of antihypertensive drugs are needed to achieve a more personalized treatment of hypertension and hypertension-mediated organ damage in women.

Pre and postnatal exposure to 900 MHz electromagnetic fields induce inflammation and oxidative stress, and alter renin-angiotensin system components differently in male and female offsprings

AIMS

This study was designed to investigate inflammation, oxidative stress and renin-angiotensin system components in brain and kidney tissues of female and male rats prenatally and/or postnatally exposed to 900 MHz electromagnetic field (EMF). It is aimed to evaluate the biological effects of 900 MHz EMF exposure due to the increase in mobile phone use and especially the more widespread use of the GSM 900 system.

MAIN METHODS

Male and female Wistar albino offsprings were divided into four groups of control, prenatal, postnatal, and prenatal+postnatal exposed to 900 MHz EMF for 1 h/day (23 days during pregnancy for prenatal period, 40 days for postnatal period). The brain and kidney tissues were collected when they reached puberty.

KEY FINDINGS

It was found that the total oxidant status, IL-2, IL-6, and TNF-α levels increased (p < 0.001) and the total antioxidant status levels decreased (p < 0.001) in all three EMF groups comparing to controls in both male and female brain and kidney tissues. The renin- angiotensin system components such as angiotensinogen, renin, angiotensin type 1 and type 2 receptors, and MAS1-like G protein-coupled receptor expression were higher (p < 0.001) in all three EMF exposure groups comparing to controls in both male and female brain and kidney tissues. Although there are some differences of the levels of proinflammatory markers, ROS components and RAS components in brain and kidney tissues between males and females, the common result of all groups was increase in oxidative stress, inflammation markers and angiotensin system components with exposure to 900 MHz EMF.

SIGNIFICANCE

In conclusion, our study suggested that the 900 MHz EMF can activate brain and kidney renin-angiotensin system, and this activation is maybe related to inflammation and oxidative stress in both male and female offsprings.

Progesterone levels associated with proteinuria in male diabetes mellitus patients: A cross-sectional retrospective study

INTRODUCTION

The relationship between progesterone (P) and diabetic nephropathy (DKD) is unclear. Herein, we investigated the relationship between progesterone and DKD in men and postmenopausal women with type 2 diabetes mellitus. MATERIALS AND METHODS: We recruited 3,556 male and postmenopausal female patients and obtained the dominance ratio (OR) and corresponding 95% confidence intervals (CIs) associated with progesterone by logistic regression analysis after adjusting for potentially confounding variants.

RESULTS

We found that progesterone levels were significantly lower in the massive proteinuria and microproteinuria groups compared with the non-DKD group for male patients. Also, microproteinuria and massive proteinuria prevalence were higher in the first (lowest) progesterone quartile than in the second to fourth quartiles. After adjusting for confounders, compared with the first (lowest) progesterone quartile group, the OR for the second to fourth quartiles in the male microproteinuria subgroup, were: Q2: 0.846 (95% CI: 0.581-1.233, P = 0.385); Q3: 0.667 (95% CI: 0.45-0988, P = 0.044); Q4: 0.597 (95% CI: 0.393-0.907, P = 0.016). In the male massive proteinuria subgroup, the OR for the third quartile group was 0.418 (95% CI: 0.201-0.867, P = 0.019). In contrast, no significant association was detected between progesterone and DKD prevalence in the female group.

CONCLUSIONS

Progesterone levels were negatively associated with DKD incidence in hospitalized male patients with type 2 diabetes mellitus.

Sexual Dimorphism in the Expression of Cardiac and Hippocampal Renin-Angiotensin and Kallikrein–Kinin Systems in Offspring from Mice Exposed to Alcohol during Gestation

Prenatal alcohol exposure (PAE) impairs fetal development. Alcohol consumption was shown to modulate the renin–angiotensin system (RAS). This study aimed to analyze the effects of PAE on the expression of the renin–angiotensin system (RAS) and kallikrein–kinin system (KKS) peptide systems in the hippocampus and heart of mice of both sexes. C57Bl/6 mice were exposed to alcohol during pregnancy at a concentration of 10% (v/v). On postnatal day 45 (PN45), mouse hippocampi and left ventricles (LV) were collected and processed for messenger RNA (mRNA) expression of components of the RAS and KKS. In PAE animals, more pronounced expression of AT1 and ACE mRNAs in males and a restored AT2 mRNA expression in females were observed in both tissues. In LV, increased AT2, ACE2, and B2 mRNA expressions were also observed in PAE females. Furthermore, high levels of H2O2 were observed in males from the PAE group in both tissues. Taken together, our results suggest that modulation of the expression of these peptidergic systems in PAE females may make them less susceptible to the effects of alcohol.

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.

Visceral fat and attribute-based medicine in chronic kidney disease

Visceral adipose tissue plays a central role in obesity and metabolic syndrome and is an independent risk factor for both cardiovascular and metabolic disorders. Increased visceral adipose tissue promotes adipokine dysregulation and insulin resistance, leading to several health issues, including systemic inflammation, oxidative stress, and activation of the renin-angiotensin-aldosterone system. Moreover, an increase in adipose tissue directly and indirectly affects the kidneys by increasing renal sodium reabsorption, causing glomerular hyperfiltration and hypertrophy, which leads to increased proteinuria and kidney fibrosis/dysfunction. Although the interest in the adverse effects of obesity on renal diseases has grown exponentially in recent years, the relationship between obesity and renal prognosis remains controversial. This may be attributed to the long clinical course of obesity, numerous obesity-related metabolic complications, and patients' attributes. Multiple individual attributes influencing the pathophysiology of fat accumulation make it difficult to understand obesity. In such cases, it may be effective to elucidate the pathophysiology by conducting research tailored to individual attributes from the perspective of attribute-based medicine/personalized medicine. We consider the appropriate use of clinical indicators necessary, according to attributes such as chronic kidney disease stage, level of visceral adipose tissue accumulation, age, and sex. Selecting treatments and clinical indicators based on individual attributes will allow for advancements in the clinical management of patients with obesity and chronic kidney disease. In the clinical setting of obesity-related nephropathy, it is first necessary to accumulate attribute-based studies resulting from the accurate evaluation of visceral fat accumulation to establish evidence for promoting personalized medicine.

Collecting duct renin regulates potassium homeostasis in mice

AIM

The kaliuretic action of the renin-angiotensin-aldosterone system (RAAS) is well established as highlighted by hyperkalemia side effect of RAAS inhibitors but such action is usually ascribed to systemic RAAS. The present study addresses the involvement of intrarenal RAAS in K+ homeostasis with emphasis on locally generated renin within the collecting duct (CD).

METHODS

Wild-type (Floxed) and CD-specific deletion of renin (CD renin KO) mice were treated for 7 days with a high K+ (HK) diet to investigate the role of CD renin in kaliuresis regulation and further define the underlying mechanism with emphasis on analysis of intrarenal aldosterone biosynthesis.

RESULTS

In floxed mice, renin levels were elevated in the renal medulla and urine following a 1-week HK diet, indicating activation of the intrarenal renin. CD renin KO mice had blunted HK-induced intrarenal renin response and developed impaired kaliuresis and elevated plasma K+ level (4.45 ± 0.14 vs. 3.89 ± 0.04 mM, p < 0.01). In parallel, HK-induced intrarenal aldosterone and CYP11B2 expression along with expression of renal outer medullary K+ channel (ROMK), calcium-activated potassium channel subunit alpha-1 (α-BK), α-Na+ -K+ -ATPase, and epithelial sodium channel (β-ENaC and cleaved-γ-ENaC) expression were all significantly blunted in CD renin KO mice in contrast to the unaltered responses of plasma aldosterone and adrenal CYP11B2.

CONCLUSION

Taken together, these results support a kaliuretic action of CD renin during HK intake.

Aldosterone, Renin, and Aldosterone-to-Renin Ratio Variability in Screening for Primary Aldosteronism

CONTEXT

The plasma aldosterone concentration (PAC), renin, and aldosterone-to-renin ratio (ARR) are used to screen for primary aldosteronism (PA). Substantial intra-individual variability of PAC and ARR using plasma renin activity in the context of usual antihypertensive therapy has been described, but there is no data on ARR variability calculated using direct renin concentration (DRC).

OBJECTIVE

To describe the intra-individual variability of PAC, DRC, and ARR in the absence of interfering medications in patients with and without PA.

DESIGN

Retrospective cohort study.

PATIENTS

Hypertensive patients referred for investigation of PA, with at least 2 ARR measurements while off interfering medications.

SETTING

Endocrine hypertension service of a tertiary center, from May 2017 to July 2021.

MAIN OUTCOME MEASURES

PAC, DRC, and ARR variability was calculated as coefficient of variation (CV) and percent difference (PD).

RESULTS

Analysis of 223 patients (55% female, median age 52 years), including 162 with confirmed PA, demonstrated high variability with a sample CV of 22-25% in the PAC and sample CV of 41% to 42% in the DRC and ARR in both the PA and non-PA groups. The degree of variability was substantially higher than the assays' analytical CV. Sixty-two patients (38%) with PA had at least one ARR below 70 pmol/L:mU/L (2.4 ng/dL:mU/L), a cut-off for first-line screening of PA.

CONCLUSIONS

Significant intra-individual variability in PAC, DRC, and hence ARR occurs in a large proportion of patients being investigated for PA. These findings support the need for at least 2 ARR before PA is excluded or further investigated.

Sex Differences in Heart Failure Mortality with Preserved, Mildly Reduced and Reduced Ejection Fraction: A Retrospective, Single-Center, Large-Cohort Study

BACKGROUND

Heart failure (HF) is one of the leading causes of death worldwide. Studies show that women have better survival rates than men despite higher hospitalizations. However, little is known about differences in mortality and predictors of death in women and men with HF with preserved (HFpEF), mildly reduced (HFmrEF), and reduced ejection fraction (HFrEF).

METHODS

From February 2017 to September 2020, mortality and predictors of death were analyzed in women and men with HF. Baseline data included clinical characteristics and echocardiographic findings.

RESULTS

A total of 11,282 patients, 63.9 ± 14.4 years, including 6256 (55.4%) males, were studied. Females were older, had a higher baseline mean left ventricular ejection fraction (LVEF) and lower left ventricular diastolic diameter. During follow-ups, 1375 (22%) men and 925 (18.4%) women died. Cumulative incidence of death was higher in men with HFrEF but similar for HFmrEF and HFpEF. Cox regression for death showed renal dysfunction, stroke, diabetes, atrial fibrillation, age, LVEF, valve disease, MI, and hypertensive CMP as independent death predictors for all HF patients.

CONCLUSIONS

Women had a better prognosis than men in HFrEF and similar mortality for HFmrEF and HFpEF, but sex was not an independent predictor of death for all HF subtypes.

Influence of sex on renin-angiotensin-aldosterone system metabolites and enzymes in Doberman Pinschers

BACKGROUND

Estrogen modulates the renin-angiotensin-aldosterone system (RAAS) in women, but sex differences have not been fully explored in dogs.

OBJECTIVE

We hypothesized that the RAAS profile of intact female (IF) Doberman Pinschers (DP) would differ from spayed female (SF) and intact male (IM) DP.

ANIMALS

Eighteen healthy DP (6 IF, 6 SF, 6 IM).

METHODS

Absolute and indexed RAAS metabolites, angiotensin-converting enzyme (ACE) and ACE2 activities, and genotypes (pyruvate kinase dehydrogenase 4, titin, and ACE variants) were compared among sex groups using Kruskal-Wallis or chi-square tests, and linear regression controlling for age. Data are expressed as median (minimum, maximum) and P < .05 was considered significant.

RESULTS

The ACE activity was higher in IF DP (656 pmol/L; 436, 784) compared to SF DP (411 pmol/L; 287, 451; P = .01) and IM DP (365 pmol/L; 276, 1200; P = .04) after controlling for age. Angiotensin II, angiotensin I, and plasma renin activity marker (PRA-S) were higher in IF DP compared to SF DP, but not significantly (P ≤ .25). After controlling for age, angiotensin 1-7/angiotensin I was lower in IF DP compared to SF DP (P = .01). Genotypes did not differ among groups. Most DP (94%) were ACE variant positive.

CONCLUSIONS AND CLINICAL SIGNIFICANCE

Sex and reproductive status influenced the RAAS of DP, with IF DP showing genotype-independent higher ACE activity. These findings hold implications for sterilization practices in female dogs, and support sex and reproductive status as a source of variability in RAAS studies. Additionally, the frequency of the ACE gene variant was very high in this group of DP.

Natriuretic Peptides—New Targets for Neurocontrol of Blood Pressure via Baroreflex Afferent Pathway

Natriuretic peptides (NPs) induce vasodilation, natriuresis, and diuresis, counteract the renin–angiotensin–aldosterone system and autonomic nervous system, and are key regulators of cardiovascular volume and pressure homeostasis. Baroreflex afferent pathway is an important reflex loop in the neuroregulation of blood pressure (BP), including nodose ganglion (NG) and nucleus tractus solitarius (NTS). Dysfunction of baroreflex would lead to various hypertensions. Here, we carried out functional experiments to explore the effects of NPs on baroreflex afferent function. Under physiological and hypertensive condition (high-fructose drinking-induced hypertension, HFD), BP was reduced by NPs through NG microinjection and baroreflex sensitivity (BRS) was enhanced via acute intravenous NPs injection. These anti-hypertensive effects were more obvious in female rats with the higher expression of NPs and its receptor A/B (NPRA/NPRB) and lower expression of its receptor C (NPRC). However, these effects were not as obvious as those in HFD rats compared with the same gender control group, which is likely to be explained by the abnormal expression of NPs and NPRs in the hypertensive condition. Our data provide additional evidence showing that NPs play a crucial role in neurocontrol of BP regulation via baroreflex afferent function and may be potential targets for clinical management of metabolic-related hypertension.

Hypertension Was Associated with Higher Tumor Stages in Papillary Thyroid Cancer: A Large Sample Single-Center Study

Background: Hypertension (HTN) is known to increase the risk of thyroid cancer. However, few studies have explored the association between HTN and the prognostic factors of papillary thyroid cancer (PTC). Methods: We retrospectively evaluated 2838 PTC patients treated with surgery at our center between January 2017 and September 2020. The association between both HTN and antihypertensive drug use and the clinicopathological features of the PTC patients was analyzed. The odds ratios (ORs) were estimated using both univariate and multivariate logistic regression models, which were adjusted for the patients' age, sex, and thyroid-stimulating hormone level. Results: A total of 2838 patients were enrolled in this study, including 409 patients with HTN. In the multivariate analysis, HTN was associated with larger tumor size [OR = 1.51, 95% confidence interval (CI): 1.10-2.07], lymph node metastasis (OR = 1.43, 95% CI: 1.02-1.99), and higher tumor stages (OR = 1.79, 95% CI: 1.12-2.86). There was no statistical difference between females >40 years of age and any pathological features, while a positive association was observed between older males and larger tumors (OR = 1.87, 95% CI: 1.01-3.45), and lymph node metastasis (OR = 2.01, 95% CI: 1.08-3.73). No statistical difference was found in the effects of taking alone calcium channel blockers, angiotensin-converting enzyme inhibitors/angiotensin II-receptor blockers, and their combination on the pathological features of PTC. Conclusion: PTC patients with HTN, particularly males of age >40, tend to have invasive features. Common antihypertension therapy appears to exert no effect on the pathological characteristics of these patients.

Distinct pathophysiological pathways in women and men with heart failure

AIMS

Clinical differences between women and men have been described in heart failure (HF). However, less is known about the underlying pathophysiological mechanisms. In this study, we compared multiple circulating biomarkers to gain better insights into differential HF pathophysiology between women and men.

METHODS AND RESULTS

In 537 women and 1485 men with HF, we compared differential expression of a panel of 363 biomarkers. Then, we performed a pathway over-representation analysis to identify differential biological pathways in women and men. Findings were validated in an independent HF cohort (575 women, 1123 men). In both cohorts, women were older and had higher left ventricular ejection fraction (LVEF). In the index and validation cohorts respectively, we found 14/363 and 12/363 biomarkers that were relatively up-regulated in women, while 21/363 and 14/363 were up-regulated in men. In both cohorts, the strongest up-regulated biomarkers in women were leptin and fatty acid binding protein-4, compared to matrix metalloproteinase-3 in men. Similar findings were replicated in a subset of patients from both cohorts matched by age and LVEF. Pathway over-representation analysis revealed increased activity of pathways associated with lipid metabolism in women, and neuro-inflammatory response in men (all p &lt; 0.0001).

CONCLUSION

In two independent cohorts of HF patients, biomarkers associated with lipid metabolic pathways were observed in women, while biomarkers associated with neuro-inflammatory response were more active in men. Differences in inflammatory and metabolic pathways may contribute to sex differences in clinical phenotype observed in HF, and provide useful insights towards development of tailored HF therapies.

Sex differences in hypertension. Do we need a sex-specific guideline?

Hypertension is the most prevalent cardiovascular disorder and the leading cause of death worldwide in both sexes. The prevalence of hypertension is lower in premenopausal women than in men of the same age, but sharply increases after the menopause, resulting in higher rates in women aged 65 and older. Awareness, treatment, and control of hypertension are better in women. A sex-pooled analysis from 4 community-based cohort studies found increasing cardiovascular risk beginning at lower systolic blood pressure thresholds for women than men. Hormonal changes after the menopause play a substantial role in the pathophysiology of hypertension in postmenopausal women. Female-specific causes of hypertension such as the use of contraceptive agents and assisted reproductive technologies have been identified. Hypertensive disorders in pregnancy are associated with increased risk of maternal, fetal, and neonatal morbidity and mortality, as well as with a greater risk of developing cardiovascular disease later in life. Hypertension-mediated organ damage was found to be more prevalent in women, thus increasing the cardiovascular risk. Sex differences in pharmacokinetics have been observed, but their clinical implications are still a matter of debate. There are currently no sufficient data to support sex-based differences in the efficacy of antihypertensive treatment. Adverse drug reactions are more frequently reported in women. Women are still underrepresented in large clinical trials in hypertension, and not all of them report sex-specific results. Therefore, it is of utmost importance to oblige scientists to include women in clinical trials and to consider sex as a biological variable.

Relationship Between Risks for Obstructive Sleep Apnea, Resistant Hypertension, and Aldosterone Among African American Adults in the Jackson Heart Study

BACKGROUND

African Americans have a higher prevalence of resistant hypertension compared with Caucasians. Racial differences in obstructive sleep apnea (OSA) and increased aldosterone level may explain the racial disparity in resistant hypertension prevalence. Therefore, the purpose of this study is to investigate if aldosterone level and hypertension status differ by risks for OSA (e.g., obesity, loud snoring, and daytime sleepiness) and how aldosterone level varies with hypertension severity and control among African Americans.

METHODS

A cross-sectional analysis was performed using baseline data on 5,052 African American adults in the Jackson Heart Study to investigate the relationships of interest using multivariable linear and multinomial logistic regression models adjusted for potential confounders. Risks for OSA were defined by a "risk score" consisting of the number of risks for OSA.

RESULTS

Of the 5,052 participants, 623 had no risks for OSA. Body mass index was the highest among those with a risk score of 6. About 39% of the sample had no hypertension, 29% had controlled hypertension, 26% had uncontrolled hypertension, and 6% had resistant hypertension. Higher odds of having uncontrolled hypertension or resistant hypertension were present in those with a higher risk score compared with those without risks for OSA. Log-aldosterone level increased with each additional risk for OSA (P-trend <0.05). Similarly, log-aldosterone also increased with more severe hypertension (P-trend <0.001). The highest aldosterone level was found in those with resistant hypertension that was inadequately controlled with medications.

CONCLUSIONS

Risks for OSA were positively associated with resistant hypertension and higher aldosterone level in African American adults.

Angiotensin-(1-7), a protective peptide against vascular aging

Vascular aging is a complex and multifaceted process that provokes profound molecular, structural, and functional changes in the vasculature. Eventually, these profound aging alterations make arteries more prone to vascular disease, including hypertension, atherosclerosis and other arterial complications that impact the organism beyond the cardiovascular system and accelerate frailty. For these reasons, preventing or delaying the hallmarks of vascular aging is nowadays a major health goal, especially in our aged societies. In this context, angiotensin(Ang)-(1-7), a major player of the protective branch of the renin-angiotensin system, has gained relevance over recent years as growing knowledge on its anti-aging properties is being unveiled. Here, we briefly review the main actions of Ang-(1-7) against vascular aging. These include protection against vascular cell senescence, anti-inflammatory and antioxidant effects together with the induction of cytoprotective systems. Ang-(1-7) further ameliorates endothelial dysfunction, a hallmark of vascular aging and disease, attenuates fibrosis and calcification and promotes protective angiogenesis and repair. Although further research is needed to better understand the anti-aging properties of Ang-(1-7) on the vasculature, this heptapeptide arises as a promising pharmacological tool for preventing vascular aging and frailty.

Salt Sensitivity of Blood Pressure and Aldosterone: Interaction Between the Lysine-specific Demethylase 1 Gene, Sex, and Age

CONTEXT

Salt sensitivity of blood pressure (SSBP) is associated with increased cardiovascular risk, especially in individuals of African descent, although the underlying mechanisms remain obscure. Lysine-specific demethylase 1 (LSD1) is a salt-sensitive epigenetic regulator associated with SSBP and aldosterone dysfunction. An LSD1 risk allele in humans is associated with SSBP and lower aldosterone levels in hypertensive individuals of African but not European descent. Heterozygous knockout LSD1 mice display SSBP and aldosterone dysregulation, but this effect is modified by age and biological sex. This might explain differences in cardiovascular risk with aging and biological sex in humans.

OBJECTIVE

This work aims to determine if LSD1 risk allele (rs587618) carriers of African descent display a sex-by-age interaction with SSBP and aldosterone regulation.

METHODS

We analyzed 297 individuals of African and European descent from the HyperPATH cohort. We performed multiple regression analyses for outcome variables related to SSBP and aldosterone.

RESULTS

LSD1 risk allele carriers of African (but not European) descent had greater SSBP than nonrisk homozygotes. Female LSD1 risk allele carriers of African descent had greater SSBP, mainly relationship-driven by women with low estrogen (postmenopausal). There was a statistically significant LSD1 genotype-sex interaction in aldosterone response to angiotensin II stimulation in individuals aged 50 years or younger, with female carriers displaying decreased aldosterone responsiveness.

CONCLUSION

SSBP associated with LSD1 risk allele status is driven by women with a depleted estrogen state. Mechanisms related to a resistance to develop SSBP in females are uncertain but may relate to an estrogen-modulating effect on mineralocorticoid receptor (MR) activation and/or LSD1 epigenetic regulation of the MR.

Basic mechanisms of SARS-CoV-2 infection. What endocrine systems could be implicated?

Although SARS-CoV-2 viral attacks starts by the interaction of spike protein (S Protein) to ACE2 receptor located at the cell surface of respiratory tract and digestive system cells, different endocrine targets, endocrine organs and metabolic conditions are of fundamental relevance for understanding disease progression and special outcomes, in particular those of fatal consequences for the patient. During pandemic, moreover, a specific phenotype of COVID-19 metabolic patient has been described, characterized by being at particular risk of worse outcomes. In the present paper we describe the mechanism of viral interaction with endocrine organs, emphasizing the specific endocrine molecules of particular relevance explaining COVID-19 disease evolution and outcomes.

Outcome-Based Decision-Making Algorithm for Treating Patients with Primary Aldosteronism

BACKGROUND

Optimal management of primary aldosteronism (PA) is crucial due to the increased risk of cardiovascular and cerebrovascular diseases. Adrenal venous sampling (AVS) is the gold standard method for determining subtype but is technically challenging and invasive. Some PA patients do not benefit clinically from surgery. We sought to develop an algorithm to improve decision- making before engaging in AVS and surgery in clinical practice.

METHODS

We conducted the ongoing Korean Primary Aldosteronism Study at two tertiary centers. Study A involved PA patients with successful catheterization and a unilateral nodule on computed tomography and aimed to predict unilateral aldosterone-producing adenoma (n=367). Study B involved similar patients who underwent adrenalectomy and aimed to predict postoperative outcome (n=330). In study A, we implemented important feature selection using the least absolute shrinkage and selection operator regression.

RESULTS

We developed a unilateral PA prediction model using logistic regression analysis: lowest serum potassium level ≤3.4 mEq/L, aldosterone-to-renin ratio ≥150, plasma aldosterone concentration ≥30 ng/mL, and body mass index <25 kg/m2 (area under the curve, 0.819; 95% confidence interval, 0.774 to 0.865; sensitivity, 97.6%; specificity, 25.5%). In study B, we identified female, hypertension duration <5 years, anti-hypertension medication <2.5 daily defined dose, and the absence of coronary artery disease as predictors of clinical success, using stepwise logistic regression models (sensitivity, 94.2%; specificity, 49.3%). We validated our algorithm in the independent validation dataset (n=53).

CONCLUSION

We propose this new outcome-driven diagnostic algorithm, simultaneously considering unilateral aldosterone excess and clinical surgical benefits in PA patients.

Gender differences in new hypoglycemic drug effects on renal outcomes: a systematic review

INTRODUCTION

Lifetime diabetes risk is greater in women than in men. Women with diabetes mellitus (DM) have a greater prevalence of diabetic kidney disease (DKD) risk factors. The diagnosis of DM is often delayed in women, with poorer outcomes and with expected therapeutic goals missed.

AREA COVERED

A systematic literature review following PRISMA guidelines was conducted in the PubMed gateway of the MEDLINE database and Clinicaltrials.gov. The purpose of our research was to establish the sex differences on renal outcomes in users of the new hypoglycemic drugs: sodium-glucose transport protein 2 inhibitors (SGLT-2i), dipeptidyl peptidase-IV Inhibitors (DPP-IVi) and glucagon-like peptide-1 inhibitors (GLP-1i).

EXPERT OPINION

New hypoglycemic drugs represent promising tools in the treatment and prevention of severe complications of diabetes, cardiovascular diseases and chronic kidney disease. Even if renal outcomes are investigated in both randomized controlled trials and cardiovascular outcome trials, gender-based analysis is not always performed. This may lead to relevant information for risk-benefit evaluation and therapeutic choices being missed, with gender-based equality in outcomes lacking. Our systematic review demonstrated that the gap among sexes in DKD can be partially filled using new hypoglycemic drugs. Sexual dimorphism analysis could represent a keystone for the development of adequate gender-specific therapies.

Emerging Roles for G Protein-Coupled Estrogen Receptor 1 in Cardio-Renal Health: Implications for Aging

Cardiovascular (CV) and renal diseases are increasingly prevalent in the United States and globally. CV-related mortality is the leading cause of death in the United States, while renal-related mortality is the 8th. Despite advanced therapeutics, both diseases persist, warranting continued exploration of disease mechanisms to develop novel therapeutics and advance clinical outcomes for cardio-renal health. CV and renal diseases increase with age, and there are sex differences evident in both the prevalence and progression of CV and renal disease. These age and sex differences seen in cardio-renal health implicate sex hormones as potentially important regulators to be studied. One such regulator is G protein-coupled estrogen receptor 1 (GPER1). GPER1 has been implicated in estrogen signaling and is expressed in a variety of tissues including the heart, vasculature, and kidney. GPER1 has been shown to be protective against CV and renal diseases in different experimental animal models. GPER1 actions involve multiple signaling pathways: interaction with aldosterone and endothelin-1 signaling, stimulation of the release of nitric oxide, and reduction in oxidative stress, inflammation, and immune infiltration. This review will discuss the current literature regarding GPER1 and cardio-renal health, particularly in the context of aging. Improving our understanding of GPER1-evoked mechanisms may reveal novel therapeutics aimed at improving cardio-renal health and clinical outcomes in the elderly.

Characterization of the intrarenal renin-angiotensin system in cats with naturally occurring chronic kidney disease

BACKGROUND

The role of the renin-angiotensin-aldosterone system in cats with chronic kidney disease (CKD) is incompletely understood.

OBJECTIVE

To characterize components of the intrarenal renin-angiotensin system (RAS) in cats with CKD.

ANIMALS

Eleven cats with naturally occurring CKD (CKD group) and 8 healthy control cats.

METHODS

Renal tissue samples were evaluated by reverse-transcription polymerase chain reaction for renin, angiotensinogen, angiotensin-converting enzyme (ACE), and angiotensin II type 1 receptor transcript levels, and by liquid chromatography-mass spectrometry for quantification of angiotensin I, II, III, and IV concentrations. Linear mixed models were used to compare gene transcript levels and concentrations of angiotensin peptides between groups.

RESULTS

Cats of the CKD group were significantly older (P < .001) and more likely to be neutered (P = .007) than healthy control cats. Kidneys from cats with CKD had significantly higher transcript levels of angiotensinogen (P < .001) and lower transcript levels of ACE (P < .001) than those from control cats. Renal angiotensin I concentrations were increased in CKD compared with control kidneys (P = .001). No other significant differences in renal transcript levels or angiotensin peptide concentrations were noted between groups.

CONCLUSION AND CLINICAL IMPORTANCE

The intrarenal RAS might be activated in cats with CKD. Small sample size and differences in age, neuter status, and dietary sodium intake between groups might have limited the ability to identify a significant difference in concentration of renal angiotensin II.

Sex and Gender Related Differences in Diabetic Kidney Disease

Diversity in sex and gender are important considerations in the pathogenesis, prognostication, research, and management of diabetic kidney disease (DKD). Sex and gender differences in the disease risk, disease-specific mechanisms, and outcomes in DKD may be attributed to biological differences between males and females at the cellular and tissue level, inconsistencies in the diagnostic and assessment tools used in chronic kidney disease and DKD, as well societal differences in the way men, women, and gender-diverse individuals self-manage and interact with health care systems. This review outlines key considerations related to the impact of sex on DKD, specifically elaborating on how they contribute to observed differences in disease epidemiology, pathogenesis, and treatment strategies. We also highlight the effect of gender on DKD progression and care.

Heart Failure Subtypes and Cardiomyopathies in Women

Heart failure affects over 2.6 million women and 3.4 million men in the United States with known sex differences in epidemiology, management, response to treatment, and outcomes across a wide spectrum of cardiomyopathies that include peripartum cardiomyopathy, hypertrophic cardiomyopathy, stress cardiomyopathy, cardiac amyloidosis, and sarcoidosis. Some of these sex-specific considerations are driven by the cellular effects of sex hormones on the renin-angiotensin-aldosterone system, endothelial response to injury, vascular aging, and left ventricular remodeling. Other sex differences are perpetuated by implicit bias leading to undertreatment and underrepresentation in clinical trials. The goal of this narrative review is to comprehensively examine the existing literature over the last decade regarding sex differences in various heart failure syndromes from pathophysiological insights to clinical practice.

Implications of testicular ACE2 and the renin-angiotensin system for SARS-CoV-2 on testis function

Although many studies have focused on SARS-CoV-2 infection in the lungs, comparatively little is known about the potential effects of the virus on male fertility. SARS-CoV-2 infection of target cells requires the presence of furin, angiotensin-converting enzyme 2 (ACE2) receptors, and transmembrane protease serine 2 (TMPRSS2). Thus, cells in the body that express these proteins might be highly susceptible to viral entry and downstream effects. Currently, reports regarding the expression of the viral entry proteins in the testes are conflicting; however, other members of the SARS-CoV family of viruses - such as SARS-CoV - have been suspected to cause testicular dysfunction and/or orchitis. SARS-CoV-2, which displays many similarities to SARS-CoV, could potentially cause similar adverse effects. Commonalities between SARS family members, taken in combination with sparse reports of testicular discomfort and altered hormone levels in patients with SARS-CoV-2, might indicate possible testicular dysfunction. Thus, SARS-CoV-2 infection has the potential for effects on testis somatic and germline cells and experimental approaches might be required to help identify potential short-term and long-term effects of SARS-CoV-2 on male fertility.

The Identikit of Patient at Risk for Severe COVID-19 and Death: The Dysregulation of Renin-Angiotensin System as the Common Theme

Since the first months of the coronavirus disease 2019 (COVID-19) pandemic, several specific physiologic traits, such as male sex and older age, or health conditions, such as overweight/obesity, arterial hypertension, metabolic syndrome, and type 2 diabetes mellitus, have been found to be highly prevalent and associated with increased risk of adverse outcomes in hospitalized patients. All these cardiovascular morbidities are widespread in the population and often coexist, thus identifying a common patient phenotype, characterized by a hyper-activation of the "classic" renin-angiotensin system (RAS) and mediated by the binding of angiotensin II (Ang II) to the type 1-receptor. At the same time, the RAS imbalance was proved to be crucial in the genesis of lung injury after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, where angiotensin-converting-enzyme-2 (ACE2) is not only the receptor for SARS-CoV-2, but its down-regulation through internalization and shedding, caused by the virus binding, leads to a further dysregulation of RAS by reducing angiotensin 1-7 (Ang 1-7) production. This focused narrative review will discuss the main available evidence on the role played by cardiovascular and metabolic conditions in severe COVID-19, providing a possible pathophysiological link based on the disequilibrium between the two opposite arms of RAS.

The Renin-Angiotensin-Aldosterone System in Postmenopausal Women: The Promise of Hormone Therapy

Estradiol (E2) plays an underrecognized role in modulating body-wide systems, including important interactions with the renin-angiotensin-aldosterone system (RAAS). The RAAS is an immunomodulating system that is critical for maintaining homeostasis across multiple organ systems. The diverse interactions between E2 and the RAAS help maintain cardiometabolic homeostasis, including successful physiologic responses to trauma and infectious pathogens. Estradiol deficiency (ie, menopause) results in impaired responses and increased susceptibility to infectious pathogens. Both immune and cardiometabolic function decline with reduced E2 production, in part because the RAAS becomes dysregulated by E2 deficiency, leaving RAAS predominantly in its proinflammatory state and predisposing to systemic low-grade inflammation. Estradiol deficiency and RAAS dysregulation contribute to impaired immune responses and increased incidence of cardiac hypertrophy, hypertension, atherosclerotic cardiovascular disease, arrhythmias, and heart failure. The RAAS consists of dual, counterbalancing pathways-proinflammatory and anti-inflammatory. Estradiol is a signaling agent that plays a major role in determining which RAAS pathway predominates. The proinflammatory pathway is activated early in response to infection or trauma, followed by up-regulation of the anti-inflammatory pathway, to resolve inflammation and to restore homeostasis. Estradiol influences activation of the "switch" to restore the anti-inflammatory state. The dysregulated RAAS is a primary target of current cardiovascular therapeutics focused on blocking portions of its proinflammatory pathway. However, RAAS-modifying pharmaceuticals often provide imperfect solutions to these physiologic disruptions and underscore the need for improved approaches to menopausal medicine. Estradiol therapy and optimal lifestyle practices combined with RAAS-modifying pharmaceuticals may be an ideal strategy to optimize postmenopausal health.