Association of testosterone with estrogen abolishes the beneficial effects of estrogen treatment by increasing ROS generation in aorta endothelial cells

Specialized Pro-resolving Mediator Improves Vascular Relaxation via Formyl Peptide Receptor-2

BACKGROUND

The resolution of inflammation is an active phenomenon important for switching off inflammatory processes once the harmful stimuli are removed and facilitate the return to homeostasis. Specialized pro-resolving mediators (SPMs), such as lipoxin A4, resolvin D1, and resolvin E1, derived from ω-3 or ω-6 polyunsaturated fatty acids, are crucial for the resolution of inflammation. We hypothesized that SPMs are decreased in hypertension which contributes to the acetylcholine-induced contraction in resistance arteries, which are well known to be mediated by leukotrienes and prostaglandins. Moreover, treatment with SPMs will decrease this contraction via formyl peptide receptor-2 (FPR-2) in resistance arteries from spontaneously hypertensive rats (SHR).

METHODS AND RESULTS

We performed a comprehensive eicosanoid lipid panel analysis, and our data showed for the first time that precursors of SPMs are decreased in SHR, limiting the production of SPMs and resolution of inflammation in vivo. This phenomenon was associated with an increase in lipid peroxidation in resistance arteries. Although SPMs did not abolish acetylcholine-induced contraction, these lipid mediators improved endothelial function in arteries from SHR via FPR-2 activation at nanomolar concentrations. SPMs also buffered TNF-α-induced reactive oxygen species generation in endothelial cells from C57Bl/6 mice.

CONCLUSIONS

We suggest that FPR-2 and SPMs could be revealed as a new target or therapeutic agent to improve vascular function in arteries from hypertensive rats.

Cigarette smoking and erectile dysfunction: an updated review with a focus on pathophysiology, e-cigarettes, and smoking cessation

Introduction

Cigarette smoking has major health implications and causes substantial damage to all organ systems. Approximately one-third of men are active smokers worldwide, and most men are unaware that cigarette smoking can contribute to erectile dysfunction (ED).

Objectives

This article aims to provide a comprehensive overview of research conducted on cigarette smoking and ED, with a particular focus on pathophysiology, electronic cigarettes (e-cigarettes), and smoking cessation.

Methods

A manual literature search was conducted on all research conducted on cigarette smoking and ED up to October 2022.

Results

Substantial evidence is now available showing that past and current cigarette smoking has dose-dependent associations with ED in studies controlling for age and important health comorbidities. Cigarette smoke contains nicotine, carbon monoxide, oxidant chemicals, and metals that can damage the endothelium and disrupt erectile processes. For current smokers, smoking abstinence can strengthen the endothelium and reverse diminished erectile function. The effect of e-cigarettes on endothelial damage and ED remains largely untested. E-cigarettes expose users to fine and ultrafine particles and toxins that can increase risk of cardiovascular injury, but these acute effects appear less potent than conventional cigarettes (long-term cardiovascular effects are still unknown). E-cigarettes are therefore likely to have less harmful effects on ED than conventional cigarettes.

Conclusions

Smoking cessation programs that focus on nicotine replacement therapy (transdermal patches, gum, or inhalers), behavioral counseling, social support, and education programs can be effective approaches to ED treatment in active smokers. Temporarily transferring from regular cigarettes to e-cigarettes—which transmit some of the same carcinogens as conventional cigarettes and are likely to have some long-term cardiovascular effects that disrupt erectile function—might also be useful for long-term smoking cessation and treatment of ED.

The sex-dependent response to psychosocial stress and ischaemic heart disease

Stress is an important risk factor for modern chronic diseases, with distinct influences in males and females. The sex specificity of the mammalian stress response contributes to the sex-dependent development and impacts of coronary artery disease (CAD). Compared to men, women appear to have greater susceptibility to chronic forms of psychosocial stress, extending beyond an increased incidence of mood disorders to include a 2- to 4-fold higher risk of stress-dependent myocardial infarction in women, and up to 10-fold higher risk of Takotsubo syndrome-a stress-dependent coronary-myocardial disorder most prevalent in post-menopausal women. Sex differences arise at all levels of the stress response: from initial perception of stress to behavioural, cognitive, and affective responses and longer-term disease outcomes. These fundamental differences involve interactions between chromosomal and gonadal determinants, (mal)adaptive epigenetic modulation across the lifespan (particularly in early life), and the extrinsic influences of socio-cultural, economic, and environmental factors. Pre-clinical investigations of biological mechanisms support distinct early life programming and a heightened corticolimbic-noradrenaline-neuroinflammatory reactivity in females vs. males, among implicated determinants of the chronic stress response. Unravelling the intrinsic molecular, cellular and systems biological basis of these differences, and their interactions with external lifestyle/socio-cultural determinants, can guide preventative and therapeutic strategies to better target coronary heart disease in a tailored sex-specific manner.

Androgens and Non-Genomic vascular responses in hypertension

Arterial hypertension is a global public health concern. In the last few years, the interest in androgen deficiency has been growing, and the association between androgens and high blood pressure (BP) is still controversial. One purpose of this review was to summarize the available findings in order to clarify whether male sex steroid hormones have beneficial or harmful effect on BP. The second purpose was to enhance the recognition of the acute non-genomic sex-independent vasorelaxing effect of androgens. Remarkably, BP variation is expected to be a consequence of the androgen-induced vasorelaxation which reduces systemic BP; hence the in vivo vasodepressor, hypotensive, and antihypertensive responses of androgens were also analyzed. This article reviews the current understanding of the physiological regulation of vascular smooth muscle contractility by androgens. Additionally, it summarizes older and more recent data on androgens, and some of the possible underlying mechanisms of relaxation, structural-functional differences in the androgen molecules, and their designing ability to induce vasorelaxation. The clinical relevance of these findings in terms of designing future therapeutics mainly the 5-reduced metabolite of testosterone, 5β-dihydrotestosterone, is also highlighted. Literature collected through a PubMed database search, as well as our experimental work, was used for the present review.

Orchiectomy but not adjuvant-induced arthritis induces structural modifications in rat aortas

Purpose: This study aimed to verify whether Adjuvant-Induced Arthritis (AIA) and/or Orchiectomy (ORX) modify the expression of the Nox1, Nox2 and Nox4 isoforms, the endothelial function or the structure of rat aortas. Methods: Sixty-three Wistar rats were distributed into four groups: 1) Control; 2) ORX; 3) AIA; 4) Orchiectomy plus to Arthritis-induction (ORX/AIA). Thus, 21 days after the onset of AIA (by intradermal injection of Mycobacterium tuberculosis), the presence of Nox1, Nox2 and Nox4, the acetylcholine (ACh)-induced relaxation and the media layer thickness were assessed in the aorta taken from these animals. Results: The Nox1, Nox2 and Nox4 were immunostained in intima, media and adventitia layers of aortas taken from all studied groups and AIA apparently increased this immunostaining. These modifications of Nox1, Nox2 or Nox4 expression, however, were not confirmed by Western blotting. In addition, neither AIA nor ORX changed the endothelial function, but ORX increased the media layer thickness in the studied aortas. Conclusion: The present study showed weak clues of increased expression of Nox1, Nox2 and Nox4 as a result of AIA, as well as of Nox1 reduction caused by ORX. In addition, the endothelial function was not modified in the aortas of these animals by both AIA and/or ORX. On the other hand, ORX increased significantly the aorta media layer thickness in the studied animals, which was apparently mitigated by AIA.

Sex Differences in Molecular Mechanisms of Cardiovascular Aging

Cardiovascular disease (CVD) is still the leading cause of illness and death in the Western world. Cardiovascular aging is a progressive modification occurring in cardiac and vascular morphology and physiology where increased endothelial dysfunction and arterial stiffness are observed, generally accompanied by increased systolic blood pressure and augmented pulse pressure. The effects of biological sex on cardiovascular pathophysiology have long been known. The incidence of hypertension is higher in men, and it increases in postmenopausal women. Premenopausal women are protected from CVD compared with age-matched men and this protective effect is lost with menopause, suggesting that sex-hormones influence blood pressure regulation. In parallel, the heart progressively remodels over the course of life and the pattern of cardiac remodeling also differs between the sexes. Lower autonomic tone, reduced baroreceptor response, and greater vascular function are observed in premenopausal women than men of similar age. However, postmenopausal women have stiffer arteries than their male counterparts. The biological mechanisms responsible for sex-related differences observed in cardiovascular aging are being unraveled over the last several decades. This review focuses on molecular mechanisms underlying the sex-differences of CVD in aging.

Naoxintong Capsule Activates the Nrf2/HO-1 Signaling Pathway and Suppresses the p38α Signaling Pathway Via Estrogen Receptors to Ameliorate Heart Remodeling in Female Mice With Postmenopausal Hypertension

ABSTRACT

Limited treatments are available for alleviating heart remodeling in postmenopausal hypertension. The cardioprotective effect of naoxintong (NXT) has been widely accepted. This study aimed to explore the effects of NXT on pathological heart remodeling in a postmenopausal hypertension mouse model in vivo and H9c2 cardiomyocytes in vitro. In vivo, ovariectomy combined with chronic angiotensin II infusion was used to establish the postmenopausal hypertension animal model. NXT significantly ameliorated cardiac remodeling as indicated by a reduced ratio of heart weight/body weight and left ventricle weight/body weight, left ventricular wall thickness, diameter of cardiomyocytes, and collagen deposition in the heart. NXT also significantly increased the expression of estrogen receptors (ERs) and downregulated the expression of nicotinamide adenine dinucleotide phosphate oxidase 2 (Nox2). In vitro, NXT treatment greatly suppressed angiotensin II-induced cardiac hypertrophy, cardiac fibrosis, and excessive oxidative stress as proven by reducing the diameter of H9c2 cardiomyocytes, expression of hypertrophy and fibrosis markers, intracellular reactive oxygen species, and oxidative enzymes. Mechanistically, NXT significantly upregulated the expression of ERs, which activated the Nrf2/HO-1 signaling pathway and inhibited the phosphorylation of the p38α pathway. Collectively, the results indicated that NXT administration might attenuate cardiac remodeling through upregulating the expression of ERs, which activated the Nrf2/HO-1 signaling pathway, inhibited the phosphorylation of the p38α signaling pathway, and reduced oxidative stress.

Th17 cells-linked mechanisms mediate vascular dysfunction induced by testosterone in a mouse model of gender-affirming hormone therapy

Clinical data point to adverse cardiovascular events elicited by testosterone replacement therapy. Testosterone is the main hormone used in gender-affirming hormone therapy (GAHT) by transmasculine people. However, the cardiovascular impact of testosterone in experimental models of GAHT remains unknown. Sex hormones modulate T cells activation, and immune mechanisms contribute to cardiovascular risk. The present study evaluated whether testosterone negatively impacts female cardiovascular function by enhancing Th17 cells-linked effector mechanisms. Female (8 weeks-old) C57BL/6J mice received testosterone (48 mg.Kg^-1.week^-1) for 8 weeks. Male mice were used for phenotypical comparisons. The hormone-treatment in female mice increased circulating testosterone to levels observed in male mice. Testosterone increased lean body mass and body mass index, and decreased perigonadal fat mass, mimicking clinical findings. After 8 weeks, testosterone decreased endothelium-dependent vasodilation and increased circulating Th17 cells. After 24 weeks, testosterone increased blood pressure in female mice. Ovariectomy did not intensify phenotypical or cardiovascular effects by testosterone. Female mice lacking T and B cells [Rag1 knockout (^-/-)], as well as female mice lacking IL-17 receptor (IL-17Ra^-/-), did not exhibit vascular dysfunction induced by testosterone. Testosterone impaired endothelium-dependent vasodilation in female mice lacking γδ T cells, similarly to the observed in wild type female mice. Adoptive transfer of CD4⁺ T cells restored testosterone-induced vascular dysfunction in Rag1^-/- female mice. Together, these data suggest that CD4⁺ T cells, most likely Th17 cells, are central to vascular dysfunction induced by testosterone in female mice, indicating that changes in immune cells balance are important in the GAHT in transmasculine people.

High-dose Nandrolone Decanoate induces oxidative stress and inflammation in retroperitoneal adipose tissue of male rats

The non-therapeutic use of the androgenic anabolic steroid Nandrolone Decanoate is popular due to its effects on physical performance and body composition, especially for its lipolytic and anabolic effects associated. However, high doses of such drugs are often associated with a series of pathologies related to unbalanced redox homeostasis, which, in turn, can be linked to inflammation. The oxidative stress onset could deregulate the secretion of cytokines, evidencing a dysfunctional adipocyte. Thus, the aim of this study was to investigate the effect of supraphysiological doses of Nandrolone Decanoate on redox homeostasis of retroperitoneal fatpad of male rats and its relationship with cytokines-based inflammatory signaling. Hydrogen peroxide production was assessed in the retroperitoneal fat pad of adult male rats which received either 10 mg kg of Nandrolone Decanoate or only a vehicle. Also, catalase, superoxide dismutase and glutathione peroxidase activities were measured, together with total reduced thiols and protein carbonylation, as well as IL-1β, TNF-α, and IL-6 local levels. High doses of Nandrolone Decanoate caused an increase in the hydrogen peroxide production, together with lower activities of the antioxidant enzymes and lower levels of total reduced thiol. There were also higher protein carbonylation and greater levels of IL-1β, TNF-α, and IL-6 in the treated group compared to control group. Therefore, it was possible to verify that high doses of Nandrolone Decanoate cause oxidative stress and induce higher inflammatory signaling in retroperitoneal fat pad of male rats.

Endothelial Dysfunction in Chronic Kidney Disease, from Biology to Clinical Outcomes: A 2020 Update

The vascular endothelium is a dynamic, functionally complex organ, modulating multiple biological processes, including vascular tone and permeability, inflammatory responses, thrombosis, and angiogenesis. Endothelial dysfunction is a threat to the integrity of the vascular system, and it is pivotal in the pathogenesis of atherosclerosis and cardiovascular disease. Reduced nitric oxide (NO) bioavailability is a hallmark of chronic kidney disease (CKD), with this disturbance being almost universal in patients who reach the most advanced phase of CKD, end-stage kidney disease (ESKD). Low NO bioavailability in CKD depends on several mechanisms affecting the expression and the activity of endothelial NO synthase (eNOS). Accumulation of endogenous inhibitors of eNOS, inflammation and oxidative stress, advanced glycosylation products (AGEs), bone mineral balance disorders encompassing hyperphosphatemia, high levels of the phosphaturic hormone fibroblast growth factor 23 (FGF23), and low levels of the active form of vitamin D (1,25 vitamin D) and the anti-ageing vasculoprotective factor Klotho all impinge upon NO bioavailability and are critical to endothelial dysfunction in CKD. Wide-ranging multivariate interventions are needed to counter endothelial dysfunction in CKD, an alteration triggering arterial disease and cardiovascular complications in this high-risk population.

Sex differences in vascular aging in response to testosterone

Large elastic arterial stiffening and endothelial dysfunction are phenotypic characteristics of vascular aging, a major risk factor for age-associated cardiovascular diseases. Compared to men, vascular aging in women appears to be slowed until menopause, whereafter vascular aging accelerates to match that seen in men. These sex differences in vascular aging have been attributed to changes in sex hormones that occur with aging. Although the role of estradiol in vascular aging in women has been highlighted in recent aging research, little is known about the impact of declining testosterone concentrations in both sexes. Importantly, while androgen concentrations generally decline with age in men, there are data that indicate reductions in androgen concentrations in women as well. Evidence suggests that low testosterone is associated with impaired endothelial function and increased arterial stiffness in men, although the effect of androgens on vascular aging in women remains unclear. Testosterone may modulate vascular aging by mitigating the effects of oxidative stress and inflammation, although there is sex specificity to this effect. The purpose of this review is to present and summarize the research regarding sex differences in vascular aging in response to androgens, specifically testosterone. Because exercise is a potent lifestyle factor for slowing and reversing vascular aging, we briefly summarize the available literature regarding the regulatory function of testosterone on vascular adaptations to exercise training.

Moderate Hypothermia Modifies Coronary Hemodynamics and Endothelium-Dependent Vasodilation in a Porcine Model of Temperature Management

Background Hypothermia has been associated with therapeutic benefits including reduced mortality and better neurologic outcomes in survivors of cardiac arrest. However, undesirable side effects have been reported in patients undergoing coronary interventions. Using a large animal model of temperature management, we aimed to describe how temperature interferes with the coronary vasculature. Methods and Results Coronary hemodynamics and endothelial function were studied in 12 pigs at various core temperatures. Left circumflex coronary artery was challenged with intracoronary nitroglycerin, bradykinin, and adenosine at normothermia (38°C) and mild hypothermia (34°C), followed by either rewarming (38°C; n=6) or moderate hypothermia (MoHT; 32°C, n=6). Invasive coronary hemodynamics by Doppler wire revealed a slower coronary blood velocity at 32°C in the MoHT protocol (normothermia 20.2±11.2 cm/s versus mild hypothermia 18.7±4.3 cm/s versus MoHT 11.3±5.3 cm/s, P=0.007). MoHT time point was also associated with high values of hyperemic microvascular resistance (>3 mm Hg/cm per second) (normothermia 2.0±0.6 mm Hg/cm per second versus mild hypothermia 2.0±0.8 mm Hg/cm per second versus MoHT 3.4±1.6 mm Hg/cm per second, P=0.273). Assessment of coronary vasodilation by quantitative coronary analysis showed increased endothelium-dependent (bradykinin) vasodilation at 32°C when compared with normothermia (normothermia 6.96% change versus mild hypothermia 9.01% change versus MoHT 25.42% change, P=0.044). Results from coronary reactivity in vitro were in agreement with angiography data and established that endothelium-dependent relaxation in MoHT completely relies on NO production. Conclusions In this porcine model of temperature management, 34°C hypothermia and rewarming (38°C) did not affect coronary hemodynamics or endothelial function. However, 32°C hypothermia altered coronary vasculature physiology by slowing coronary blood flow, increasing microvascular resistance, and exacerbating endothelium-dependent vasodilatory response.

Hormones and oxidative stress: an overview

In aerobes, oxygen is essential for maintenance of life. However, incomplete reduction of oxygen leads to generation of reactive oxygen species. These oxidants oxidise biological macromolecules present in their vicinity and thereby impair cellular functions causing oxidative stress (OS). Aerobes have evolved both enzymatic and nonenzymatic antioxidant defences to protect themselves from OS. Although hormones as means of biological coordination involve in regulation of physiological activities of tissues by regulating metabolism, any change in their normal titre leads to pathophysiological states. While, hormones such as melatonin, insulin, oestrogen, progesterone display antioxidant features, thyroid hormone, corticosteroids and catecholamines elicit free radical generation and OS, and the role of testosterone in inducing OS is debateable. This review is an attempt to understand the impact of free radical generation and cross talk between the hormones modulating antioxidant defence system under various pathophysiological conditions.

Cellular Mechanisms of Aortic Aneurysm Formation

Aortic aneurysms are a common vascular disease in Western populations that can involve virtually any portion of the aorta. Abdominal aortic aneurysms are much more common than thoracic aortic aneurysms and combined they account for >25 000 deaths in the United States annually. Although thoracic and abdominal aortic aneurysms share some common characteristics, including the gross anatomic appearance, alterations in extracellular matrix, and loss of smooth muscle cells, they are distinct diseases. In recent years, advances in genetic analysis, robust molecular tools, and increased availability of animal models have greatly enhanced our knowledge of the pathophysiology of aortic aneurysms. This review examines the various proposed cellular mechanisms responsible for aortic aneurysm formation and identifies opportunities for future studies.

Late Onset of Estrogen Therapy Impairs Carotid Function of Senescent Females in Association with Altered Prostanoid Balance and Upregulation of the Variant ERα36

Recent analysis of clinical trials on estrogen therapy proposes the existence of a therapeutic window of opportunity for the cardiovascular benefits of estrogens, which depend on women's age and the onset of therapy initiation. In this study, we aimed to determine how vascular senescence and the onset of estrogen treatment influence the common carotid artery (CCA) function in senescent and non-senescent females. Ovariectomized female senescence-accelerated (SAMP8) or non-senescent (SAMR1) mice were treated with vehicle (OVX) or 17β-estradiol starting at the day of ovariectomy (early-onset, E₂E) or 45 days after surgery (late-onset, E₂L). In SAMR1, both treatments, E₂E and E₂L, reduced constriction to phenylephrine (Phe) in CCA [(AUC) OVX: 193.8 ± 15.5; E₂E: 128.1 ± 11.6; E₂L: 130.2 ± 15.8, p = 0.004] in association with positive regulation of NO/O2- ratio and increased prostacyclin production. In contrast, E₂E treatment did not modify vasoconstrictor responses to Phe in OVX-SAMP8 and, yet, E₂L increased Phe vasoconstriction [(AUC) OVX: 165.3 ± 10; E₂E: 183.3 ± 11.1; E₂L: 256.3 ± 30.4, p = 0.005]. Increased vasoconstriction in E₂L-SAMP8 was associated with augmented thromboxane A2 and reduced NO production. Analysis of wild-type receptor alpha (ERα66) expression and its variants revealed an increased expression of ERα36 in E₂L-SAMP8 in correlation with unfavorable effects of estrogen in those animals. In conclusion, estrogen exerts beneficial effects in non-senescent CCA, regardless of the initiation of the therapy. In senescent CCA, however, estrogen loses its beneficial action even when administered shortly after ovariectomy and may become detrimental when given late after ovariectomy. Aging and onset of estrogen treatment are two critical factors in the mechanism of action of this hormone in CCA.

Role of Gender in Regulation of Redox Homeostasis in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is one of the diseases with a well-established gender dimorphism. The prevalence of PAH is increased in females with a ratio of 4:1, while poor survival prognosis is associated with the male gender. Nevertheless, the specific contribution of gender in disease development and progression is unclear due to the complex nature of the PAH. Oxidative and nitrosative stresses are important contributors in PAH pathogenesis; however, the role of gender in redox homeostasis has been understudied. This review is aimed to overview the possible sex-specific mechanisms responsible for the regulation of the balance between oxidants and antioxidants in relation to PAH pathobiology.

Androgens drive microvascular endothelial dysfunction in women with polycystic ovary syndrome: role of the endothelin B receptor

KEY POINTS

Polycystic ovary syndrome (PCOS) is a complex syndrome with cardiovascular risk factors, including obesity and insulin resistance. PCOS is also associated with high androgens, increases the risk of cardiovascular dysfunction in women. Due to the complexity of PCOS, had it has been challenging to isolate specific causes of the cardiovascular dysfunction. Our measure of cardiovascular dysfunction (endothelial dysfunction) was most profound in lean women with PCOS. The endothelin-1-induced vasodilation in these PCOS subject, was dependent on the ET_B R but was not NO-dependent. We also demonstrated oestrogen administration improved endothelial function in lean and obese women with PCOS likely because oestrogen increased NO availability. Our studies indicate a primary role for androgens in cardiovascular dysfunction in PCOS.

ABSTRACT

Endothelin-1 (ET-1) is an indicator of endothelial injury and dysfunction and is elevated in women with androgen excess polycystic ovary syndrome (AE-PCOS). The endothelin B receptor (ET_B R) subtype mediates vasodilatation, but is blunted in women with PCOS. We hypothesized that androgen drives endothelial dysfunction in AE-PCOS women and oestradiol (EE) administration reverses these effects. We assessed microvascular endothelial function in women with (7 lean and 7 obese) and without AE-PCOS (controls, 6 lean, 7 obese). Only obese AE-PCOS women were insulin resistant (IR). We evaluated cutaneous vascular conductance (%CVC_max ) with laser Doppler flowmetry during low dose intradermal microdialysis ET-1 perfusions (1, 3, 4, 5 and 7 pmol) with either lactated Ringer solution alone, or with ET_B R (BQ-788), or nitric oxide (NO) inhibition (l-NAME). Log[ET-1]-%maxCVC dose-response curves demonstrated reduced vasodilatory responses to ET-1 in lean AE-PCOS (logED₅₀ , 0.59 ± 0.08) versus lean controls (logED₅₀ , 0.49 ± 0.09, P < 0.05), but not compared to obese AE-PCOS (logED₅₀ , 0.65 ± 0.09). ET_B R inhibition decreased ET-1-induced vasodilatation in AE-PCOS women (logED₅₀ , 0.64 ± 0. 22, P < 0.05). This was mechanistically observed at the cellular level, with ET-1-induced, DAF-FM-measurable endothelial cell NO production, which was abrogated by dihydrotestosterone in an androgen receptor-dependent manner. EE augmented the cutaneous vasodilating response to ET-1(logED₅₀ 0.29 ± 0.21, 0.47 ± 0.09, P < 0.05 for lean and obese, respectively). Androgens drive endothelial dysfunction in lean and obese AE-PCOS. We propose that the attenuated ET-1-induced vasodilatation in AE-PCOS is a consequence of androgen receptor-mediated, suppressed ET_B R-stimulated NO production, and is reversed with EE.

Clinical Impact of Blood Testosterone Concentration on Cardio-Ankle Vascular Index in Female Patients With Type 2 Diabetes Mellitus

Background

Information regarding testosterone as a significant risk factor of cardiovascular disease (CVD) in female patients with type 2 diabetes mellitus (DM) is limited. However, some clinical studies reported the importance of cardio-ankle vascular index (CAVI) as a novel physiological marker of arterial function in type 2 DM. This cross-sectional study aimed to elucidate the clinical effects of blood testosterone concentration on CAVI in female patients with type 2 DM.

Methods

A total of 238 postmenopausal patients including 97 with a history of CVD with type 2 DM (age (mean ± standard deviation (SD)), 73 ± 9 years) were enrolled. CAVI was measured according to the standard technique, and serum total testosterone concentration (T-T) was also measured as a testosterone level marker in vivo. The relationship between CAVI and T-T was evaluated.

Results

CAVI is significantly higher (CVD vs. non-CVD: 10.2 ± 1.2 vs. 9.2 ± 1.0, P < 0.001), and log-T-T significantly lower (CVD vs. non-CVD: 1.2 ± 0.2 ng/dL vs. 1.5 ± 0.2 ng/dL, P < 0.001) in patients with CVD than those without CVD. CAVI was significantly negatively correlated with log-T-T (r = -0.41; P < 0.001). Furthermore, multiple regression analysis indicated that CVD (β = 0.23; P < 0.001) and log-T-T (β = -0.18; P < 0.01) were selected as independent subordinate variables for CAVI.

Conclusions

This study showed that T-T was independently inversely associated with CAVI, indicating that low testosterone concentration is a considerable risk factor for the progression of arterial dysfunction in female patients with type 2 DM.

Detrimental Effects of Testosterone Addition to Estrogen Therapy Involve Cytochrome P-450-Induced 20-HETE Synthesis in Aorta of Ovariectomized Spontaneously Hypertensive Rat (SHR), a Model of Postmenopausal Hypertension

Postmenopausal period has been associated to different symptoms such as hot flashes, vulvovaginal atrophy, hypoactive sexual desire disorder (HSDD) and others. Clinical studies have described postmenopausal women presenting HSDD can benefit from the association of testosterone to conventional hormonal therapy. Testosterone has been linked to development of cardiovascular diseases including hypertension and it also increases cytochrome P-450-induced 20-HETE synthesis which in turn results in vascular dysfunction. However, the effect of testosterone plus estrogen in the cardiovascular system is still very poorly studied. The aim of the present study is to evaluate the role of cytochrome P-450 pathway in a postmenopausal hypertensive female treated with testosterone plus estrogen. For that, hypertensive ovariectomized rats (OVX-SHR) were used as a model of postmenopausal hypertension and four groups were created: SHAM-operated (SHAM), ovariectomized SHR (OVX), OVX treated for 15 days with conjugated equine estrogens [(CEE) 9.6 μg/Kg/day/po] or CEE associated to testosterone [(CEE+T) 2.85 mg/kg/weekly/im]. Phenylephrine-induced contraction and generation of reactive oxygen species (ROS) were markedly increased in aortic rings from OVX-SHR compared to SHAM rats which were restored by CEE treatment. On the other hand, CEE+T abolished vascular effects by CEE and augmented both systolic and diastolic blood pressure of SHR. Treatment of aortic rings with the CYP/20-HETE synthesis inhibitor HET0016 (1 μM) reduced phenylephrine hyperreactivity and the augmented ROS generation in the CEE+T group. These results are paralleled by the increased CYP4F3 protein expression and activity in aortas of CEE+T. In conclusion, we showed that association of testosterone to estrogen therapy produces detrimental effects in cardiovascular system of ovariectomized hypertensive females via CYP4F3/20-HETE pathway. Therefore, our findings support the standpoint that the CYP/20-HETE pathway is an important therapeutic target for the prevention of cardiovascular disease in menopausal women in the presence of high levels of testosterone.

Sex differences in abdominal aortic aneurysms

Abdominal aortic aneurysm (AAA) is a vascular disorder with a high case fatality rate in the instance of rupture. AAA is a multifactorial disease, and the etiology is still not fully understood. AAA is more likely to occur in men, but women have a greater risk of rupture and worse prognosis. Women are reportedly protected against AAA possibly by premenopausal levels of estrogen and are, on average, diagnosed at older ages than men. Here, we review the present body of research on AAA pathophysiology in humans, animal models, and cultured cells, with an emphasis on sex differences and sex steroid hormone signaling.

Relationship Between Serum Total Testosterone Concentration and Augmentation Index at Radial Artery in Japanese Postmenopausal Patients

Background

The significance of testosterone as a risk factor for cardiovascular disease (CVD) in females is controversial. This cross-sectional study aimed to elucidate the relationship between serum total testosterone concentration (T-T) and augmentation index at the radial artery (r-AIx) as a marker of arterial function in Japanese postmenopausal patients.

Methods

A total of 447 postmenopausal patients with traditional cardiovascular risk factors and/or a history of CVD (age (mean ± standard deviation (SD)), 73 ± 10 years) were enrolled. r-AIx was measured using tonometry, and the association between r-AIx and various clinical parameters, including T-T, was determined.

Results

r-AIx significantly increased (CVD vs. non-CVD: 99±11% vs. 91±11%, P < 0.001) and T-T significantly decreased (CVD vs. non-CVD: 0.31 ± 0.13 ng/mL vs. 0.49 ± 0.23 ng/mL, P < 0.001) in patients with CVD than in those without CVD. A significant negative correlation (r = -0.48; P < 0.001) between r-AIx and T-T was observed. Furthermore, multiple regression analysis indicated that T-T (t value = -7.7; P < 0.001), height (t value = -5.3; P < 0.001), d-ROMs test as a marker of oxidative stress in vivo (t value = 3.2; P < 0.001), CVD (t value = 2.9; P < 0.01), and pulse rate (t value = -2.7; P < 0.01) were independent variables for r-AIx as a subordinate factor.

Conclusion

This study revealed that low T-T is an important determining factor for an increase in r-AIx in Japanese postmenopausal patients. A prospective multicenter study with a large sample size is required to confirm the results of this study.

Zinc Finger E-Box Binding Protein 2 (ZEB2) Suppress Apoptosis of Vascular Endothelial Cells Induced by High Glucose Through Mitogen-Activated Protein Kinases (MAPK) Pathway Activation

Background

Hyperglycemia has been confirmed to damage endothelial function of vascular and microvascular. The regulation of zinc finger E-box binding protein 2 (ZEB2) on vascular endothelial cells (VECs) is reported rarely. Our study investigates the role of ZEB2 on the apoptosis of VECs induced by high glucose through MAPK pathway.

Material/Methods

Downregulated and upregulated expression of ZEB2 in human umbilical vein endothelial cells (HUVECs) were performed by plasmids transfection. HUVECs are respectively treated with different concentrations of glucose (5.5 mM, 33 mM). The expression of mRNA and protein were detected by real-time quantified PCR and western blotting. Apoptotic cells were measured by flow cytometry. Proliferation and migration of HUVECs were detected by MTT assay and wound healing assay.

Results

The apoptosis of HUVECs detected by flow cytometry and western blot revealed that ZEB2 overexpression distinctly suppressed the apoptosis of HUVECs induced by high glucose. ZEB2 overexpression promoted the proliferative and migration activity of HUVECs. Besides, ZEB2 overexpression specifically accelerated the phosphorylation level of JNK, and suppressed the apoptosis and promoted the proliferative of VECs via JNK pathway.

Conclusion

ZEB2 suppress apoptosis of VECs induced by high glucose through MAPK pathway activation, which provides a novel insight and therapeutic target for endothelial injury.

Pathophysiology of Aortic Valve Stenosis: Is It Both Fibrocalcific and Sex Specific?

Our understanding of the fundamental biology and identification of efficacious therapeutic targets in aortic valve stenosis has lagged far behind the fields of atherosclerosis and heart failure. In this review, we highlight the most clinically relevant problems facing men and women with fibrocalcific aortic valve stenosis, discuss the fundamental biology underlying valve calcification and fibrosis, and identify key molecular points of intersection with sex hormone signaling.

Endothelial dysfunction and vascular disease - a 30th anniversary update

The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best-characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDH-mediated responses). As regards the latter, hydrogen peroxide (H₂ O₂ ) now appears to play a dominant role. Endothelium-dependent relaxations involve both pertussis toxin-sensitive G_i (e.g. responses to α₂ -adrenergic agonists, serotonin, and thrombin) and pertussis toxin-insensitive G_q (e.g. adenosine diphosphate and bradykinin) coupling proteins. New stimulators (e.g. insulin, adiponectin) of the release of EDRFs have emerged. In recent years, evidence has also accumulated, confirming that the release of NO by the endothelial cell can chronically be upregulated (e.g. by oestrogens, exercise and dietary factors) and downregulated (e.g. oxidative stress, smoking, pollution and oxidized low-density lipoproteins) and that it is reduced with ageing and in the course of vascular disease (e.g. diabetes and hypertension). Arteries covered with regenerated endothelium (e.g. following angioplasty) selectively lose the pertussis toxin-sensitive pathway for NO release which favours vasospasm, thrombosis, penetration of macrophages, cellular growth and the inflammatory reaction leading to atherosclerosis. In addition to the release of NO (and EDH, in particular those due to H₂ O₂ ), endothelial cells also can evoke contraction of the underlying vascular smooth muscle cells by releasing endothelium-derived contracting factors. Recent evidence confirms that most endothelium-dependent acute increases in contractile force are due to the formation of vasoconstrictor prostanoids (endoperoxides and prostacyclin) which activate TP receptors of the vascular smooth muscle cells and that prostacyclin plays a key role in such responses. Endothelium-dependent contractions are exacerbated when the production of nitric oxide is impaired (e.g. by oxidative stress, ageing, spontaneous hypertension and diabetes). They contribute to the blunting of endothelium-dependent vasodilatations in aged subjects and essential hypertensive and diabetic patients. In addition, recent data confirm that the release of endothelin-1 can contribute to endothelial dysfunction and that the peptide appears to be an important contributor to vascular dysfunction. Finally, it has become clear that nitric oxide itself, under certain conditions (e.g. hypoxia), can cause biased activation of soluble guanylyl cyclase leading to the production of cyclic inosine monophosphate (cIMP) rather than cGMP and hence causes contraction rather than relaxation of the underlying vascular smooth muscle.

Estrogen Protects the Female Heart from Ischemia/Reperfusion Injury through Manganese Superoxide Dismutase Phosphorylation by Mitochondrial p38β at Threonine 79 and Serine 106

A collective body of evidence indicates that estrogen protects the heart from myocardial ischemia/reperfusion (I/R) injury, but the underlying mechanism remains incompletely understood. We have previously delineated a novel mechanism of how 17β-estradiol (E2) protects cultured neonatal rat cardiomyocytes from hypoxia/reoxygenation (H/R) by identifying a functionally active mitochondrial pool of p38β and E2-driven upregulation of manganese superoxide dismutase (MnSOD) activity via p38β, leading to the suppression of reactive oxygen species (ROS) and apoptosis. Here we investigate these cytoprotective actions of E2 in vivo. Left coronary artery ligation and reperfusion was used to produce I/R injury in ovariectomized (OVX) female mice and in estrogen receptor (ER) null female mice. E2 treatment in OVX mice reduced the left ventricular infarct size accompanied by increased activity of mitochondrial p38β and MnSOD. I/R-induced infarct size in ERα knockout (ERKO), ERβ knockout (BERKO) and ERα and β double knockout (DERKO) female mice was larger than that in wild type (WT) mice, with little difference among ERKO, BERKO, and DERKO. Loss of both ERα and ERβ led to reduced activity of mitochondrial p38β and MnSOD at baseline and after I/R. The physical interaction between mitochondrial p38β and MnSOD in the heart was detected by co-immunoprecipitation (co-IP). Threonine 79 (T79) and serine 106 (S106) of MnSOD were identified to be phosphorylated by p38β in kinase assays. Overexpression of WT MnSOD in cardiomyocytes reduced ROS generation during H/R, while point mutation of T79 and S106 of MnSOD to alanine abolished its antioxidative function. We conclude that the protective effects of E2 and ER against cardiac I/R injury involve the regulation of MnSOD via posttranslational modification of the dismutase by p38β.

Carotid Intima-Media Thickness Is Associated with Increased Androgens in Adolescents and Young Adults with Classical Congenital Adrenal Hyperplasia

BACKGROUND/AIMS

Youth with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency develop cardiovascular disease (CVD) risk factors of obesity and hypertension. Carotid intima-media thickness (CIMT), a marker of CVD risk, is increased in CAH young adults. We examined CIMT and its relationship with androgens and obesity in adolescents/young adults with CAH.

METHODS

Twenty CAH subjects (age 16 ± 3.3 years, 50% female) and 20 matched controls were studied cross-sectionally. Eight additional obese patients with CAH were included in within-group comparisons. CIMT by high-resolution ultrasound, androgens, anthropometry, bone age (BA), and metabolic/inflammatory markers were assessed.

RESULTS

Within the CAH group, CIMT correlated with 17-hydroxyprogesterone (r = 0.48, p < 0.05) and androstenedione (r = 0.46, p < 0.05), and was greater in obese subjects. CIMT was greater in CAH males than females, but similar among CAH females with advanced BA, CAH males with normal BA, and control males. There was no difference in CIMT between CAH and controls, although high-density lipoprotein was inversely correlated with CIMT in both groups.

CONCLUSION

CIMT is associated with increased androgens in CAH adolescents and young adults, with loss of sex differences in CAH females with excess androgen exposure. Our findings highlight the importance of hormonal control for CVD prevention in CAH.

Reactive oxygen species: players in the cardiovascular effects of testosterone

Androgens are essential for the development and maintenance of male reproductive tissues and sexual function and for overall health and well being. Testosterone, the predominant and most important androgen, not only affects the male reproductive system, but also influences the activity of many other organs. In the cardiovascular system, the actions of testosterone are still controversial, its effects ranging from protective to deleterious. While early studies showed that testosterone replacement therapy exerted beneficial effects on cardiovascular disease, some recent safety studies point to a positive association between endogenous and supraphysiological levels of androgens/testosterone and cardiovascular disease risk. Among the possible mechanisms involved in the actions of testosterone on the cardiovascular system, indirect actions (changes in the lipid profile, insulin sensitivity, and hemostatic mechanisms, modulation of the sympathetic nervous system and renin-angiotensin-aldosterone system), as well as direct actions (modulatory effects on proinflammatory enzymes, on the generation of reactive oxygen species, nitric oxide bioavailability, and on vasoconstrictor signaling pathways) have been reported. This mini-review focuses on evidence indicating that testosterone has prooxidative actions that may contribute to its deleterious actions in the cardiovascular system. The controversial effects of testosterone on ROS generation and oxidant status, both prooxidant and antioxidant, in the cardiovascular system and in cells and tissues of other systems are reviewed.