Sex-difference in expression and function of beta-adrenoceptors in macrovessels: role of the endothelium

Age and sex mediated effects of estrogen and Β3-adrenergic receptor on cardiovascular pathophysiology

Sex differences are consistently identified in determining the prevalence, manifestation, and response to therapies in several systemic disorders, including those affecting the cardiovascular (CV), skeletal muscle, and nervous system. Interestingly, such differences are often more noticeable as we age. For example, premenopausal women experience a lower risk of CV disease than men of the same age. While at an advanced age, with menopause, the risk of cardiovascular diseases and adverse outcomes increases exponentially in women, exceeding that of men. However, this effect appears to be reversed in diseases such as pulmonary hypertension, where women are up to seven times more likely than men to develop an idiopathic form of the disease with symptoms developing ten years earlier than their male counterparts. Explaining this is a complex question. However, several factors and mechanisms have been identified in recent decades, including a role for sex hormones, particularly estrogens and their related receptors. Furthermore, an emerging role in these sex differences has also been suggested for β-adrenergic receptors (βARs), which are essential regulators of mammalian physiology. It has in fact been shown that βARs interact with estrogen receptors (ER), providing further demonstration of their involvement in determining sexual differences. Based on these premises, this review article focused on the β3AR subtype, which shows important activities in adipose tissue but with new and interesting roles in regulating the function of cardiomyocytes and vascular cells. In detail, we examined how β3AR and ER signaling are intertwined and whether there would be sex- and age-dependent specific effects of these receptor systems.

Sex- and Gender-Based Analysis on Norepinephrine Use in Septic Shock: Why Is It Still a Male World?

Sex and gender are fundamental health determinants and their role as modifiers of treatment response is increasingly recognized. Norepinephrine is a cornerstone of septic shock management and its use is based on the highest level of evidence compared to dopamine. The related 2021 Surviving Sepsis Campaign (SCC) recommendation is presumably applicable to both females and males; however, a sex- and gender-based analysis is lacking, thus not allowing generalizable conclusions. This paper was aimed at exploring whether sex- and gender-disaggregated data are available in the evidence supporting this recommendation. For all the studies underpinning it, four pairs of authors, including a woman and a man, extracted data concerning sex and gender, according to the Sex and Gender Equity in Research guidelines. Nine manuscripts were included with an overall population of 2126 patients, of which 43.2% were females. No sex analysis was performed and gender was never reported. In conclusion, the present manuscript highlighted that the clinical studies underlying the SCC recommendation of NE administration in septic shock have neglected the likely role of sex and gender as modifiers of treatment response, thus missing the opportunity of sex- and gender-specific guidelines.

Differences in vasomotor function of mesenteric arteries between Ossabaw minipigs with predisposition to metabolic syndrome and Göttingen minipigs

Metabolic syndrome predisposes and contributes to the development and progression of atherosclerosis. The minipig strain "Ossabaw" is characterized by a predisposition to develop metabolic syndrome. We compared vasomotor function in Ossabaw minipigs before they developed their diseased phenotype to that of Göttingen minipigs without such genetic predisposition. Mesenteric arteries of adult Ossabaw and Göttingen minipigs were dissected postmortem and mounted on a myograph for isometric force measurements. Maximal vasoconstriction to potassium chloride (KClmax) was induced. Cumulative concentration-response curves were determined in response to norepinephrine. Endothelium-dependent (with carbachol) and endothelium-independent (with nitroprusside) vasodilation were analyzed after preconstriction by norepinephrine. In a bioinformatic analysis, variants/altered base pairs within genes associated with cardiovascular disease were analyzed. KClmax was similar between the minipig strains (15.6 ± 6.7 vs. 14.1 ± 3.4 ΔmN). Vasoconstriction in response to norepinephrine was more pronounced in Ossabaw than in Göttingen minipigs (increase of force to 143 ± 48 vs. 108 ± 38% of KClmax). Endothelium-dependent and endothelium-independent vasodilation were less pronounced in Ossabaw than in Göttingen minipigs (decrease of force to 46.4 ± 29.6 vs. 16.0 ± 18.4% and to 36.7 ± 25.2 vs. 2.3 ± 3.7% of norepinephrine-induced preconstriction). Vasomotor function was not different between the sexes. More altered base pairs/variants were identified in Ossabaw than in Göttingen minipigs for the exon encoding adrenoceptor-α1A. Vasomotor function in lean Ossabaw minipigs is shifted toward vasoconstriction and away from vasodilation in comparison with Göttingen minipigs, suggesting a genetic predisposition for vascular dysfunction and atherosclerosis in Ossabaw minipigs. Thus, Ossabaw minipigs may be a better model for human cardiovascular disease than Göttingen minipigs.NEW & NOTEWORTHY Animal models with a predisposition to metabolic syndrome and atherosclerosis are attracting growing interest for translational research, as they may better mimic the variability of patients with cardiovascular disease. In Ossabaw minipigs, with a polygenic predisposition to metabolic syndrome, but without the diseased phenotype, vasoconstriction is more and vasodilation is less pronounced in mesenteric arteries than in Göttingen minipigs. Ossabaw minipigs may be a more suitable model of human cardiovascular disease.

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.

Beta blockers reduce uterine fibroid incidence in hypertensive women

OBJECTIVE

Is prior beta blocker (BB) use associated with reduced odds of the clinical incidence of leiomyomas?

WHAT IS KNOWN ALREADY

In-vitro and in-vivo evidence has supported the role of beta receptor blockade in reducing leiomyoma cell proliferation and growth. However, no population-based study to date has investigated this potential association.

STUDY DESIGN, SIZE, DURATION

A nested case-control study was conducted in a population of women aged 18-65 with arterial hypertension (n = 699,966). Cases (n = 18,918) with a leiomyoma diagnosis were matched to controls (n = 681,048) with no such diagnosis at a 1:36 ratio by age and region of origin within the United States.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This population was assembled from the Truven Health MarketScan® Research Database, which includes health insurance claims from January 1st, 2012 to December 31st, 2017. Prior use of BB wasdetermined fromoutpatient drug claims and leiomyoma development was indicated by a first-time diagnosis code. We conducted a conditional logistic regression to determine the odds of uterine fibroid development in women with prior use of BB compared to women with no such history. We then conducted subset analyses, stratifying the women by age group and by type of BB.

RESULTS

Women on a BB experienced 15% reduced odds of developing clinically recognized leiomyoma compared to non-users (OR 0.85, 95% CI 0.76-0.94). This association was significant for the 30-39 age group (OR 0.61, 95% CI 0.40-0.93) but no other age group. Of the BBs, propranolol (OR 0.58, 95% CI 0.36-95) demonstrated a significant association with reduced leiomyoma incidence and metoprolol (OR 0.82, 95% CI 0.70-0.97) was associated with lower uterine fibroid incidence after adjustment for comorbidities.

CONCLUSIONS

Hypertensive women with prior BB use experienced reduced odds of developing clinically recognized leiomyoma compared to non-users. A key predisposing risk factor for uterine leiomyoma is elevated blood pressure. Thus, the results of this analysis may have clinical relevance to women with hypertension, as the use of this drug may introduce a dual benefit of managing hypertension as well as curbing an increased risk of leiomyomas.

Sex/Gender- and Age-Related Differences in β-Adrenergic Receptor Signaling in Cardiovascular Diseases

Sex differences in cardiovascular disease (CVD) are often recognized from experimental and clinical studies examining the prevalence, manifestations, and response to therapies. Compared to age-matched men, women tend to have reduced CV risk and a better prognosis in the premenopausal period. However, with menopause, this risk increases exponentially, surpassing that of men. Although several mechanisms have been provided, including sex hormones, an emerging role in these sex differences has been suggested for β-adrenergic receptor (β-AR) signaling. Importantly, β-ARs are the most important G protein-coupled receptors (GPCRs), expressed in almost all the cell types of the CV system, and involved in physiological and pathophysiological processes. Consistent with their role, for decades, βARs have been considered the first targets for rational drug design to fight CVDs. Of note, β-ARs are seemingly associated with different CV outcomes in females compared with males. In addition, even if there is a critical inverse correlation between β-AR responsiveness and aging, it has been reported that gender is crucially involved in this age-related effect. This review will discuss how β-ARs impact the CV risk and response to anti-CVD therapies, also concerning sex and age. Further, we will explore how estrogens impact β-AR signaling in women.

Beta-blockers for Atherosclerosis Prevention: a Missed Opportunity?

PURPOSE OF REVIEW

Current guidelines for the management of arterial hypertension endorse β-adrenergic receptor blocking agents (beta-blockers, BBs) as being particularly useful for hypertension in specific situations such as symptomatic angina, tachycardia, post-myocardial infarction, heart failure with reduced ejection fraction (HFrEF), and as an alternative to angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) in hypertensive women planning pregnancy or at least of child-bearing potential. One of the most common uses of BBs is in patients with a recent myocardial infarction, with or without hypertension. Although this one use is specifically in a setting of atherosclerotic cardiovascular disease (ASCVD), it is not primarily for atheroprevention, but rather for cases with impaired systolic function, and it is intended primarily to lessen adverse cardiac remodeling and worsening of congestive heart failure (CHF). The BB class consists of numerous agents which differ widely in pharmacologic properties and physiologic effects. These differences include selectivity for β-adrenergic receptors and their subtypes, hydro- or lipophilicity, effects on blood pressure and heart rate, influence on lipoprotein and glucose metabolism, and direct impact on the artery wall, including platelet reactivity, endothelial function, infiltration of inflammatory cells and on inflammation per se, and on smooth muscle cell proliferation. Importantly, BBs are not commonly used for prevention of atherosclerosis or ASCVD per se. Many studies of early-generation BBs showed adverse effects on lipoprotein levels and metabolism of glucose and insulin and thus discouraged their use in atheroprevention. Nevertheless, newer BBs often have neutral or favorable metabolic effects on these important factors in ASCVD pathophysiology, and recent scientific studies now document direct beneficial effects of BBs on the artery wall. This document reviews both types of newer data, not only to encourage consideration of BB treatment to reduce ASCVD in the present, but also to call for future research to better explore the clinical settings in which BBs may be proven to have additional benefit in preventing ASCVD when added to the better-established treatments for dyslipidemia and diabetes.

RECENT FINDINGS

Relatively recent publications have clarified the diversity among BBs regarding adverse, neutral, or favorable effects on lipoproteins (especially triglycerides (TG) and low-density lipoprotein (LDL)) and on glucose/insulin metabolism. Specifically, the newer BBs (metoprolol ER, carvedilol ER, bisoprolol, and nebivolol) are now documented to be metabolically beneficial. These new data are complex but instructive regarding potential mechanisms of the diverse effects of various BBs on metabolism. Further and more importantly, these new data refute the traditional, but now outmoded, concept that BBs are universally harmful metabolically and therefore must be used sparingly, if at all, for atheroprevention. Recent studies have also reported exciting new data regarding how certain BBs can reduce platelet adhesion and improve the function of the major cell types in the artery wall, including the endothelium, macrophages, and smooth muscle cells. Specifically, BBs can improve endothelial function by enhancing arterial vasodilation and by reducing monocyte adhesion and transmigration. Further, BBs can decrease numbers and activity of inflammatory cells, including decreasing proliferation of smooth muscle cells and their transformation into inflammatory cells. These data help with the crucial step of distinguishing among available BBs regarding their likely overall arterial effects, whether to accelerate or prevent the development of atherosclerosis. In this regard, there is even some limited published information beyond these intermediary steps, going directly to the clinically more important endpoints of atherosclerosis and ASCVD events. The negative metabolic effects observed with the use of traditional/earlier generations of BBs have discouraged use of any BBs to prevent ASCVD. These adverse effects are not seen, however, with newer BBs. Thus, BBs continue to be a useful component of combination regimens not only in the treatment of arterial hypertension, heart failure, and arrhythmia, but also potentially in the prevention of atherosclerosis and ASCVD. Despite this exciting potential, further research is greatly needed to better establish the possible benefits of the most promising BBs as they might work in combination with other better-established atheropreventive agents. Specifically, there is a need for randomized, prospective, cardiovascular outcome trials (CVOTs) in high-risk patients, adding a BB to background LDL-lowering (statins, etc.), TG-lowering (specifically icosapent ethyl, which reduces ASCVD in patients with high TG, although apparently not via TG-lowering), and/or anti-diabetic (sodium glucose transport-2 inhibitors, SGLT2i, and glucagon-like protein-1 receptor agonists, GLP1-RA) treatments, as indicated in a given subject population.

Sex determination gene transformer regulates the male-female difference in Drosophila fat storage via the adipokinetic hormone pathway

Sex differences in whole-body fat storage exist in many species. For example, Drosophila females store more fat than males. Yet, the mechanisms underlying this sex difference in fat storage remain incompletely understood. Here, we identify a key role for sex determination gene transformer (tra) in regulating the male-female difference in fat storage. Normally, a functional Tra protein is present only in females, where it promotes female sexual development. We show that loss of Tra in females reduced whole-body fat storage, whereas gain of Tra in males augmented fat storage. Tra's role in promoting fat storage was largely due to its function in neurons, specifically the Adipokinetic hormone (Akh)-producing cells (APCs). Our analysis of Akh pathway regulation revealed a male bias in APC activity and Akh pathway function, where this sex-biased regulation influenced the sex difference in fat storage by limiting triglyceride accumulation in males. Importantly, Tra loss in females increased Akh pathway activity, and genetically manipulating the Akh pathway rescued Tra-dependent effects on fat storage. This identifies sex-specific regulation of Akh as one mechanism underlying the male-female difference in whole-body triglyceride levels, and provides important insight into the conserved mechanisms underlying sexual dimorphism in whole-body fat storage.

Sex differences in hypertension: lessons from spontaneously hypertensive rats (SHR)

Although numerous clinical and experimental studies have clearly identified a sexual dimorphism in blood pressure control, the mechanism(s) underlying gender differences in blood pressure remain unclear. Over the past two decades, numerous laboratories have utilized the spontaneously hypertensive rats (SHR) as an experimental model of essential hypertension to increase our understanding of the mechanisms regulating blood pressure in males and females. Previous work by our group and others have implicated that differential regulation of adrenergic receptors, the renin-angiotensin system, oxidative stress, nitric oxide bioavailability and immune cells contribute to sex differences in blood pressure control in SHR. The purpose of this review is to summarize previous findings to date regarding the mechanisms of blood pressure control in male versus female SHR.

Pharmacogenomic Effects of β-Blocker Use on Femoral Neck Bone Mineral Density

CONTEXT

Recent studies have shown that β-blocker (BB) users have a decreased risk of fracture and higher bone mineral density (BMD) compared to nonusers, likely due to the suppression of adrenergic signaling in osteoblasts, leading to increased BMD. There is also variability in the effect size of BB use on BMD in humans, which may be due to pharmacogenomic effects.

OBJECTIVE

To investigate potential single-nucleotide variations (SNVs) associated with the effect of BB use on femoral neck BMD, we performed a cross-sectional analysis using clinical data, dual-energy x-ray absorptiometry, and genetic data from the Framingham Heart Study's (FHS) Offspring Cohort. We then sought to validate our top 4 genetic findings using data from the Rotterdam Study, the BPROOF Study, the Malta Osteoporosis Fracture Study (MOFS), and the Hertfordshire Cohort Study.

METHODS

We used sex-stratified linear mixed models to determine SNVs that had a significant interaction effect with BB use on femoral neck (FN) BMD across 11 gene regions. We also evaluated the association of our top SNVs from the FHS with microRNA (miRNA) expression in blood and identified potential miRNA-mediated mechanisms by which these SNVs may affect FN BMD.

RESULTS

One variation (rs11124190 in HDAC4) was validated in females using data from the Rotterdam Study, while another (rs12414657 in ADRB1) was validated in females using data from the MOFS. We performed an exploratory meta-analysis of all 5 studies for these variations, which further validated our findings.

CONCLUSION

This analysis provides a starting point for investigating the pharmacogenomic effects of BB use on BMD measures.

Alpha and beta adrenergic receptors modulate keratinocyte migration

Keratinocyte migration into skin wounds is the step of the healing process that correlates with the wound closure rate. Keratinocyte migration, and wound epithelialization are decreased when beta 2-adrenergic receptors (B2AR) are activated by 1 μM epinephrine/adrenaline, resulting in delayed wound healing in human and mouse skin. In the present study, we found paradoxically, that in a subset of keratinocyte strains exposure to low concentrations of epinephrine (0.1 nM) increased, rather than decreased, their migratory rate. We find that both the alpha- and the beta-adrenergic receptors are expressed in human keratinocytes, and expression of alpha-2 AR subtypes demonstrated for the first time. Therefore, we tested if the alpha-AR could be modulating the increased migratory response observed in these cell strains. By using specific inhibitors to alpha-AR, we demonstrated that blocking A2B-AR could reverse the rapid cell migration induced by the 0.1 nM epinephrine. Phosphorylation of ERK was elevated after 1-10 minutes of the low epinephrine treatment and the A2B-AR inhibitor blocked the ERK phosphorylation. The results suggest that both the A2B-AR and B2AR mediate keratinocyte migration, in which with a low level of epinephrine treatment, A2B-AR could alter the B2AR signals and regulate the migration rate.

Cardiac Fibroblasts Mediate a Sexually Dimorphic Fibrotic Response to β-Adrenergic Stimulation

Background

Biological sex is an important modifier of cardiovascular disease and women generally have better outcomes compared with men. However, the contribution of cardiac fibroblasts (CFs) to this sexual dimorphism is relatively unexplored.

Methods and Results

Isoproterenol (ISO) was administered to rats as a model for chronic β‐adrenergic receptor (β‐AR)‐mediated cardiovascular disease. ISO‐treated males had higher mortality than females and also developed fibrosis whereas females did not. Gonadectomy did not abrogate this sex difference. To determine the cellular contribution to this phenotype, CFs were studied. CFs from both sexes had increased proliferation in vivo in response to ISO, but CFs from female hearts proliferated more than male cells. In addition, male CFs were significantly more activated to myofibroblasts by ISO. To investigate potential regulatory mechanisms for the sexually dimorphic fibrotic response, β‐AR mRNA and PKA (protein kinase A) activity were measured. In response to ISO treatment, male CFs increased expression of β1‐ and β2‐ARs, whereas expression of both receptors decreased in female CFs. Moreover, ISO‐treated male CFs had higher PKA activity relative to vehicle controls, whereas ISO did not activate PKA in female CFs.

Conclusions

Chronic in vivo β‐AR stimulation causes fibrosis in male but not female rat hearts. Male CFs are more activated than female CFs, consistent with elevated fibrosis in male rat hearts and may be caused by higher β‐AR expression and PKA activation in male CFs. Taken together, our data suggest that CFs play a substantial role in mediating sex differences observed after cardiac injury.

Sex- and Gender-Based Pharmacological Response to Drugs

In humans, the combination of all sex-specific genetic, epigenetic, and hormonal influences of biologic sex produces different in vivo environments for male and female cells. We dissect how these influences of sex modify the pharmacokinetics and pharmacodynamics of multiple drugs and provide examples for common drugs acting on specific organ systems. We also discuss how gender of physicians and patients may influence the therapeutic response to drugs. We aim to highlight sex as a genetic modifier of the pharmacological response to drugs, which should be considered as a necessary step toward precision medicine that will benefit men and women. SIGNIFICANCE STATEMENT: This study discusses the influences of biologic sex on the pharmacokinetics and pharmacodynamics of drugs and provides examples for common drugs acting on specific organ systems. This study also discusses how gender of physicians and patients influence the therapeutic response to drugs.

Sex difference in sympathetic nervous system activity and blood pressure in hypertensive patients

Increased sympathetic nervous system (SNS) activity leads to increased risk of cardiovascular morbidity and mortality. This study investigated whether there were sex differences in SNS activity among Chinese patients with hypertension. Ethnic Chinese non‐diabetic hypertensive patients aged 20–50 years were enrolled in Taiwan. A total of 970 hypertensive patients (41.0 ± 7.2 years) completed the study, 664 men and 306 women. They received comprehensive evaluations including office blood pressure (BP) measurement, 24‐h ambulatory BP monitoring, and 24‐h urine sampling assayed for catecholamine excretion. Compared to women, men were younger, had higher body mass index (BMI), office systolic BP (SBP), office diastolic BP (DBP), 24‐h ambulatory BP, and 24‐h urine catecholamine excretion. In men, 24‐h urine total catecholamine levels were correlated with 24‐h SBP (r = 0.103, p = .008) and 24‐h DBP (r = 0.083, p = .033). In women, however, there was no correlation between 24‐h urine total catecholamine levels and 24‐h ambulatory BP. Multivariate linear regression indicated that being male (β = 1.65, 95% confidence interval [CI] 0.01–3.29, p = .048) and 24‐h urine total catecholamine (β = 5.03, 95% CI 0.62–9.44, p = .025) were both independently associated with 24‐h SBP; being male was independently associated with 24‐h DBP (β = 3.55, 95% CI 2.26–4.85, p < .001). In conclusion, Chinese men with hypertension had higher SNS activity than women, and SNS activity was independently associated with 24‐h ambulatory BP in men rather than in women. These findings suggest that different hypertensive treatment strategies should be considered according to patient sex.

Androgen Effects on the Adrenergic System of the Vascular, Airway, and Cardiac Myocytes and Their Relevance in Pathological Processes

INTRODUCTION

Androgen signaling comprises nongenomic and genomic pathways. Nongenomic actions are not related to the binding of the androgen receptor (AR) and occur rapidly. The genomic effects implicate the binding to a cytosolic AR, leading to protein synthesis. Both events are independent of each other. Genomic effects have been associated with different pathologies such as vascular ischemia, hypertension, asthma, and cardiovascular diseases. Catecholamines play a crucial role in regulating vascular smooth muscle (VSM), airway smooth muscle (ASM), and cardiac muscle (CM) function and tone.

OBJECTIVE

The aim of this review is an updated analysis of the role of androgens in the adrenergic system of vascular, airway, and cardiac myocytes. Body. Testosterone (T) favors vasoconstriction, and its concentration fluctuation during life stages can affect the vascular tone and might contribute to the development of hypertension. In the VSM, T increases α1-adrenergic receptors (α ₁-ARs) and decreases adenylyl cyclase expression, favoring high blood pressure and hypertension. Androgens have also been associated with asthma. During puberty, girls are more susceptible to present asthma symptoms than boys because of the increment in the plasmatic concentrations of T in young men. In the ASM, β ₂-ARs are responsible for the bronchodilator effect, and T augments the expression of β ₂-ARs evoking an increase in the relaxing response to salbutamol. The levels of T are also associated with an increment in atherosclerosis and cardiovascular risk. In the CM, activation of α _1A-ARs and β ₂-ARs increases the ionotropic activity, leading to the development of contraction, and T upregulates the expression of both receptors and improves the myocardial performance.

CONCLUSIONS

Androgens play an essential role in the adrenergic system of vascular, airway, and cardiac myocytes, favoring either a state of health or disease. While the use of androgens as a therapeutic tool for treating asthma symptoms or heart disease is proposed, the vascular system is warmly affected.

Estrogen determines sex differences in adrenergic vessel tone by regulation of endothelial β-adrenoceptor expression

Vessels of female rats constrict less and relax more to adrenergic stimulation than vessels of males. Although we have reported that these sex-specific differences rely on endothelial β-adrenoceptors, the role of sex hormones in β-adrenoceptor expression and related vessel tone regulation is unknown. We investigated the role of estrogen, progesterone and testosterone on β-adrenoceptor expression and adrenergic vessel tone regulation, along with sex-specific differences in human mammary arteries. The sex-specific differences in vasoconstriction and vasorelaxation in rat vessels were eliminated after ovariectomy in females. Ovariectomy increased vessel vasoconstriction to norepinephrine more than twofold. Vasorelaxations by isoprenaline and a β₃-agonist were reduced after ovariectomy. Estrogen, but not progesterone substitution, restored sex-specific differences in vasoconstriction and vasorelaxation. Vascular mRNA levels of β₁- and β₃- but not β₂-adrenoreceptors were higher in vessels of females compared with males. Ovariectomy reduced these differences by decreasing β₁- and β₃- but not β₂-adrenoreceptor expression in females. Consistently, estrogen substitution restored β₁- and β₃-adrenoreceptor expression. Orchiectomy or testosterone treatment affected neither vasoconstriction and vasorelaxation nor β-adrenoceptor expression in vessels of male rats. In human mammary arteries, sex-specific differences in vasoconstriction and vasorelaxation were reduced after removal of endothelium or treatment with l-NMMA. Vessels of women showed higher levels of β₁- and β₃-adrenoceptors than in men. In conclusion, the sex-specific differences in vasoconstriction and vasorelaxation are common for rat and human vessels. In rats, these differences are estrogen but not testosterone or progesterone dependent. Estrogen determines these differences via regulation of vascular endothelial β₁- and β₃-adrenoreceptor expression. NEW & NOTEWORTHY This study proposes a mechanistic concept regulating sex-specific differences in adrenergic vasoconstriction and vasorelaxation. Estrogen increases vascular β₁- and β₃-adrenoceptor expression in female rats. This and our previous studies demonstrate that these receptors are located primarily on endothelium and when activated by norepinephrine act via nitric oxide (NO). Therefore, β-adrenergic stimulation leads to a more pronounced vasorelaxation in females. Coactivation of endothelial β₁- and β₃-adrenoreceptors leads to higher NO release in vessels of females, ultimately blunting vasoconstriction triggered by activation of smooth muscle α-adrenoceptors.

Polytropic Influence of TRIB3 rs2295490 Genetic Polymorphism on Response to Antihypertensive Agents in Patients With Essential Hypertension

Tribbles homolog 3 (TRIB3) mediating signaling pathways are closely related to blood pressure regulation. Our previous findings suggested a greater benefit on vascular outcomes in patients carrying TRIB3 (251, A > G, rs2295490) G allele with good glucose and blood pressure control. And TRIB3 (rs2295490) AG/GG genotypes were found to reduce primary vascular events in type 2 diabetic patients who received intensive glucose treatment as compared to those receiving standard glucose treatment. However, the effect of TRIB3 genetic variation on antihypertensives was not clear in essential hypertension patients. A total of 368 patients treated with conventional dosage of antihypertensives (6 groups, grouped by atenolol/bisoprolol, celiprolol, doxazosin, azelnidipine/nitrendipine, imidapril, and candesartan/irbesartan) were enrolled in our study. Genetic variations were successfully identified by sanger sequencing. A linear mixed model analysis was performed to evaluate blood pressures among TRIB3 (251, A > G) genotypes and adjusted for baseline age, gender, body mass index, systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol and other biochemical factors appropriately. Our data suggested that TRIB3 (251, A > G) AA genotype carriers showed better antihypertensive effect than the AG/GG genotype carriers [P = 0.014 for DBP and P = 0.042 for mean arterial pressure (MAP)], with a maximal reduction of DBP by 4.2 mmHg and MAP by 3.56 mmHg after azelnidipine or nitrendipine treatment at the 4th week. Similar tendency of DBP-change and MAP-change was found for imidapril (ACEI) treatment, in which marginally significances were achieved (P = 0.073 and 0.075, respectively). Against that, we found that TRIB3 (251, A > G) AG/GG genotype carriers benefited from antihypertensive therapy of ARBs with a larger DBP-change during the period of observation (P = 0.036). Additionally, stratified analysis revealed an obvious difference of the maximal blood pressure change (13 mmHg for the MAP between male and female patients with AA genotype who took ARBs). Although no significant difference in antihypertensive effect between TRIB3 (251, A > G) genotypes in patients treated with α, β-ADRs was observed, we found significant difference in age-, sex-dependent manner related to α, β-ADRs. In conclusion, our data supported that TRIB3 (251, A > G) genetic polymorphism may serve as a useful biomarker in the treatment of hypertension.

Age-, Gender-, and in Vivo Different Doses of Isoproterenol Modify in Vitro Aortic Vasoreactivity and Circulating VCAM-1

Different human-like cardiomyopathies associated to β-adrenergic stimulation are experimentally modeled in animals through variations in dose, route, and duration of administration of different cardiotoxic drugs. However, associated changes in the vasculature and their relation to systemic inflammation, and the influence of cardiovascular diseases risk factors (gender and age) upon them are seldom analyzed. Here we studied the effect of age and gender on the vasoreactivity of aortas from mice subjected to in vivo repeated β-adrenergic stimulation with different doses of isoproterenol (ISO) in association with circulating inflammatory cytokines. Young (2 months) and old (18 months) male and female mice received 0 (control), 5, 40, 80 or 160 μg/g/d of ISO (7 days, s.c.). IL-1α, IL-4 and vascular cell adhesion molecule-1 (VCAM-1) were quantified in plasma. In vitro, norepinephrine-induced vasoconstriction and acetylcholine-induced relaxation were measured in aortas. No differences in contraction, relaxation, IL-1α, and IL-4 were found between control young males and females. Age decreased contraction in males and relaxation was lower in females and abolished in males. VCAM-1 was higher in young males than in females and increased in old mice. Vasoconstriction in ISO-treated mice results as a bell-shaped curve on contraction in young and old males, with lower values in the latter. In females, ISO-160 increased contraction in young females but decreased it in old females. Vasorelaxation was reduced in ISO-treated young males and females. ISO-80 and 160 reduced vasorelaxation in old females, and intermediate doses relaxed aortas from old males. VCAM-1 was higher in young and old males with ISO-80 and 160; while VCAM-1 was higher only with ISO-160 in old females. Our results demonstrate that repeated β-adrenergic stimulation modifies vascular reactivity depending on gender, age, and dose. Females were less sensitive to alterations in vasoreactivity, and young females required a higher amount of the adrenergic stimuli than old females to show vascular alterations. Changes were independent of IL-1α and IL-4. VCAM-1 only changed in old females stimulated with ISO 160. Our results highlight the relevance of considering and comparing in the same study females and aged organisms to improve the accuracy of applications to clinical studies.