Sex differences in control of blood pressure: role of oxidative stress in hypertension in females

Nonalcoholic fatty liver disease and risk of incident young-onset hypertension: Effect modification by sex

BACKGROUND AND AIMS

Although nonalcoholic fatty liver disease (NAFLD) and hypertension are increasingly common among young adults, it is uncertain if NAFLD affects incidence of young-onset hypertension, and if the association is modified by sex. We investigated potential effect modification by sex on the association between NAFLD and incident hypertension in young adults (<40 years).

METHOD AND RESULTS

This cohort study comprised 85,789 women and 67,553 men aged <40 years without hypertension at baseline. Hepatic steatosis was assessed by liver ultrasound and classified as mild or moderate/severe. Hypertension was defined as blood pressure (BP) ≥130/80 mmHg; self-reported history of physician-diagnosed hypertension; or current use of BP-lowering medications. Cox proportional hazard models were used to estimate hazard ratios (HRs; 95% confidence intervals [CIs]) for incident hypertension by NAFLD status (median follow-up 4.5 years). A total of 25,891 participants developed incident hypertension (incidence rates per 10³ person-years: 15.6 for women and 63.5 for men). Multivariable-adjusted HRs (95% CIs) for incident hypertension comparing no NAFLD (reference) with mild or moderate/severe NAFLD were 1.68 (1.56-1.80) and 1.83 (1.60-2.09) for women and 1.21 (1.17-1.25) and 1.23 (1.17-1.30) for men, respectively. Stronger associations were consistently observed between NAFLD and incident hypertension in women, regardless of obesity/central obesity (all p-values for interaction by sex <0.001).

CONCLUSIONS

NAFLD is a potential risk factor for young-onset hypertension with a relatively greater impact in women and in those with more severe hepatic steatosis.

Hypertension after the Menopause: What Can We Learn from Experimental Studies?

Hypertension is the most prevalent cardiovascular disease of the adult population and is closely associated with serious cardiovascular events. The burden of hypertension with respect to vascular and other organ damage is greater in women. These sex differences are not fully understood. The unique feature in women is their transition to menopause accompanied by profound hormonal changes that affect the vasculature that are also associated with changes of blood pressure. Results from studies of hormone replacement therapy and its effects on the cardiovascular system are controversial, and the timing of treatment after menopause seems to be important. Therefore, revealing potential sex- and sex hormone-dependent pathophysiological mechanisms of hypertension in experimental studies could provide valuable information for better treatment of hypertension and vascular impairment, especially in postmenopausal women. The experimental rat models subjected to ovariectomy mimicking menopause could be useful tools for studying the mechanisms of blood pressure regulation after menopause and during subsequent therapy.

Sex differences in the renin-angiotensin-aldosterone system and its roles in hypertension, cardiovascular, and kidney diseases

Cardiovascular disease is a pathology that exhibits well-researched biological sex differences, making it possible for physicians to tailor preventative and therapeutic approaches for various diseases. Hypertension, which is defined as blood pressure greater than 130/80 mmHg, is the primary risk factor for developing coronary artery disease, stroke, and renal failure. Approximately 48% of American men and 43% of American women suffer from hypertension. Epidemiological data suggests that during reproductive years, women have much lower rates of hypertension than men. However, this protective effect disappears after the onset of menopause. Treatment-resistant hypertension affects approximately 10.3 million US adults and is unable to be controlled even after implementing ≥3 antihypertensives with complementary mechanisms. This indicates that other mechanisms responsible for modulating blood pressure are still unclear. Understanding the differences in genetic and hormonal mechanisms that lead to hypertension would allow for sex-specific treatment and an opportunity to improve patient outcomes. Therefore, this invited review will review and discuss recent advances in studying the sex-specific physiological mechanisms that affect the renin-angiotensin system and contribute to blood pressure control. It will also discuss research on sex differences in hypertension management, treatment, and outcomes.

Correlation between Blunted Nocturnal Decrease in Diastolic Blood Pressure and Oxidative Stress: An Observational Study

An impaired nocturnal decrease in diastolic blood pressure (DBP) increases the blood pressure (BP) load, which is a main factor in endothelial dysfunction, atherosclerosis, and arterial stiffness. We aimed to quantify some markers of oxidative stress in hypertensive patients, to compare their levels between individuals with dipper and non-dipper DBP profiles, and to assess their correlation with the nocturnal DBP (nDBP) dipping. It was an observational study that included patients older than 18 years with a diagnosis of essential hypertension who consented to participate. The collected variables were some indices of 24-h ambulatory blood pressure monitoring, demographic, epidemiological, clinical, and laboratory variables. Plasma thiobarbituric acid reactive substances (TBARS) and reduced thiols, together with serum vitamin E, vitamin A, copper (Cu), and zinc (Zn) levels were assessed as oxidative stress markers. We recruited 248 patients with a median age of 56 years (56% women). The percentage of nDBP dipping showed a weak positive correlation with reduced thiol, vitamin E, and vitamin A levels; and a weak negative correlation with Cu levels. We also found a negative correlation between nDBP dipping and the TBARS/Thiol, TBARS/Vitamin E, and TBARS/Vitamin A ratios. After multivariate analysis, we found that increased TBARS/Thiol ratio and serum Cu levels were associated with a higher risk of a non-dipper DBP profile. As in other situations of increased cardiovascular risk, an impaired nDBP decrease may coincide with abnormalities in redox status.

Sexual dimorphism in renal heme oxygenase-1 and arachidonic acid metabolizing enzymes in spontaneously hypertensive rats versus normotensive Wistar Kyoto rats

Numerous studies have demonstrated a sexual dimorphism in blood pressure (BP) control in spontaneously hypertensive rats (SHR), however the mechanisms remain to be further elucidated. Based on the established role of arachidonic acid metabolites and heme oxygenase (HO) in BP control, we hypothesize that higher BP in male SHR is associated with differential expression in renal HO and arachidonic acid metabolizing enzymes vs. female SHR. Higher BP in male SHR coincided with significant increases in renal cortical superoxide production and thiobarbituric acid reactive substances (TBARs) levels as measures of oxidative stress compared to normotensive female WKY and female SHR. The elevations in BP and oxidative stress in male SHR were also associated with a decrease in cortical heme oxygenase-1 (HO-1) expression when compared to normotensive female WKY. Although there was no sex or strain differences in cortical expression of the epoxyeicosatrienoic acids (EETs) producing enzyme, cytochrome P450 epoxygenase (CYP2C23), in male and female SHR and WKY, SHR had greater expression of the EETs metabolizing enzyme, soluble epoxide hydrolase (sEH) vs. WKY. Cortical expression of the 20-hydroxyeicosatetraenoic acid (20-HETE) producing enzyme, cytochrome P450 hydroxylase (CYP4A), was less in female WKY and SHR compared to strain-matched males and cortical 20-HETE levels were also less in female SHR vs. male SHR. Cortical cyclooxygenase-2 (COX-2) expression was significantly greater in female SHR and WKY vs. males and cortical prostaglandin E2 (PGE2) levels in female SHR was significantly greater than male WKY. In conclusion, our data suggest that sex differences in renal oxidative stress, HO-1 and arachidonic acid metabolizing enzymes could contribute to sexual dimorphism in hypertension in young SHR.

Blood pressure control status of patients with hypertension on treatment in Dessie City Northeast Ethiopia

INTRODUCTION

Uncontrolled blood pressure contributes a huge contribution to many hypertension-related complications and it is one of the unbeaten problems for patients taking antihypertensive drugs. The association of social support and other factors with uncontrolled blood pressure during the covid-19 pandemic is not well investigated. Therefore, this study explored the determinants of blood pressure control status during the COVID-19 pandemic among patients with hypertension who were on an antihypertensive treatment.

METHOD

A cross-sectional study was done from March to May 2021 among adults aged 18 or more patients with hypertension for three months or more on treatment in Dessie City. An interview-administered questionnaire was done using simple random sampling from hypertension follow-up register for 380 patients with hypertension. Blood pressure measurement was taken from their arm using a stethoscope and mercury sphygmomanometer at a sitting position with 90-degree back support. Uncontrolled blood pressure was also computed either the systolic or diastolic blood pressure greater than or less than the limit of uncontrolled blood pressure with regarding the age and diabetic status of patients. The perceived social support-related questionnaire was adopted from the Multidimensional Scale of Perceived Social Support (MSPSS) -12 item checklist. It was sum-up and transformed into three categories using tertile of their computed raw scores. The adjusted prevalence ratio with a 95 percent confidence interval (CI) was used to calculate the strength of the association between uncontrolled blood pressure and independent predictors using log-binomial regression analysis. A P-value less than 0.05 was declared as statistically significant in multivariable log-binomial regression analysis.

RESULT

A total of 360 study participants were included in this study. The prevalence of uncontrolled blood measures in patients with hypertension with a 95% CI was 55.8(50.7, 61.0). In a multivariable analysis adjusted prevalence ratio with 95% CI for poor medication adherence 1.86(1.59,2.19), being male 1.35(1.11,1.64), secondary education 0.52(0.35,0.77), and low social support 1.24(1.01, 1.54) were the predictors of uncontrolled blood pressure.

CONCLUSION

Uncontrolled blood pressure for patients with hypertension on treatment is higher during the COVID-19 pandemic. Being male, poor medication adherence, educational status and low social support are factors that contribute to uncontrolled blood pressure.

Protective effects of dietary curcumin and astaxanthin against heat-induced ROS production and skeletal muscle injury in male and female C57BL/6J mice

AIMS

This study aimed to: 1) investigate sex differences in heat-induced mitochondrial dysfunction, ROS production, and skeletal muscle injury in mice; 2) evaluate whether curcumin and astaxanthin, alone or together, would prevent those heat-induced changes.

MAIN METHODS

Male and female C57BL/6J mice were treated with curcumin and astaxanthin for 10 days, then exposed to 39.5 °C heat for up to 3 h. Heat-induced hyperthermia, changes in mitochondrial morphology and function, and oxidative damage to skeletal muscle were evaluated.

KEY FINDINGS

Although female mice had a slightly higher basal core body temperature (Tc) than male mice, peak Tc during heat exposure was significantly lower in females than in males. Heat increased ROS levels in skeletal muscle in both sexes; interestingly, the increases in ROS were greater in females than in males. Despite the above-mentioned differences, heat induced similar levels of mitochondrial fragmentation and membrane potential depolarization, caspase 3/7 activation, and injury in male and female skeletal muscle. Individual treatment of curcumin or astaxanthin did not affect basal and peak Tc but prevented heat-induced mitochondrial dysfunction, ROS increases, and apoptosis in a dose-dependent manner. Moreover, a low-dose combination of curcumin and astaxanthin, which individually showed no effect, reduced the heat-induced oxidative damage to skeletal muscle.

SIGNIFICANCE

Both male and female mice can develop mitochondrial dysfunction and oxidative stress in skeletal muscle when exposed to heat stress. High doses of either curcumin or astaxanthin limit heat-induced skeletal muscle injury, but a low-dose combination of these ingredients may increase their efficacy.

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.

Antioxidant Properties of Alpha-Lipoic (Thioctic) Acid Treatment on Renal and Heart Parenchyma in a Rat Model of Hypertension

Renal and cardiac impairments are frequent events in the presence of hypertension. Organ damage is mainly linked to oxidative stress due to high blood pressure and may be reduced by antioxidant supplementation. Alpha-lipoic acid (ALA) is one of most effective antioxidants. It is widely used as a nutritional supplement in a racemic mixture (+/–), even though the (+)-enantiomer is biologically active. This study was designed to investigate the effect of treatment with (+/–)-ALA and its enantiomers on renal and heart parenchyma in spontaneously hypertensive rats (SHR), using immunochemical and immunohistochemical techniques. The results confirmed that the oxidative mechanisms of organ alterations, due to hypertension, and characterized by glomerular and tubular lesions, left ventricular hypertrophy, and fibrosis but not by apoptosis were accompanied by proteins’ and nucleic acids’ oxidation. We found greater effectiveness of (+)-ALA compared to (+/−)-ALA in reducing oxidative stress, cardiac and renal damages in SHR. To conclude, these data propose (+)-ALA as one of the more appropriate antioxidant molecules to prevent renal and cardiac alterations associated with hypertension.

Human Umbilical Cord: Information Mine in Sex-Specific Medicine

Biological differences between sexes should be considered in all stages of research, as sexual dimorphism starts in utero leading to sex-specific fetal programming. In numerous biomedical fields, there is still a lack of stratification by sex despite primary cultured cells retaining memory of the sex and of the donor. The sex of donors in biological research must be known because variations in cells and cellular components can be used as endpoints, biomarkers and/or targets of pharmacological studies. This selective review focuses on the current findings regarding sex differences observed in the umbilical cord, a widely used source of research samples, both in the blood and in the circulating cells, as well as in the different cellular models obtainable from it. Moreover, an overview on sex differences in fetal programming is reported. As it emerges that the sex variable is still often forgotten in experimental models, we suggest that it should be mandatory to adopt sex-oriented research, because only awareness of these issues can lead to innovative research.

Gender-biased kidney damage in mice following exposure to tobacco cigarette smoke: More protection in premenopausal females

Multiple clinical studies documented renal damage in chronic cigarette smokers (CS) irrespective of their age and gender. Premenopausal female smokers are known to exert a certain cardiovascular and renal protection with undefined mechanisms. Given the multiple demographic variables within clinical studies, this experimental study was designed to be the first to assess whether gender‐biased CS‐induced kidney damage truly exists between premenopausal female and age‐matched C57Bl6J male mice when compared to their relative control groups. Following 6 weeks of CS exposure, cardiac function, inflammatory marker production, fibrosis formation, total and glomerular ROS levels, and glomerulotubular homeostasis were assessed in both genders. Although both CS‐exposed male and female mice exhibited comparable ROS fold change relative to their respective control groups, CS‐exposed male mice showed a more pronounced fibrotic deposition, inflammation, and glomerulotubular damage profile. However, the protection observed in CS‐exposed female group was not absolute. CS‐exposed female mice exhibited a significant increase in fibrosis, ROS production, and glomerulotubular alteration but with a pronounced anti‐inflammatory profile when compared to their relative control groups. Although both CS‐exposed genders presented with altered glomerulotubular homeostasis, the alteration phenotype between genders was different. CS‐exposed males showed a significant decrease in Bowman's space along with reduced tubular diameter consistent with an endocrinization pattern of chronic tubular atrophy, suggestive of an advanced stage of glomerulotubular damage. CS‐exposed female group, on the other hand, displayed glomerular hypertrophy with a mild tubular dilatation profile suggestive of an early stage of glomerulotubular damage that generally precedes collapse. In conclusion, both genders are prone to CS‐induced kidney damage with pronounced female protection due to a milder damage slope.

Positive Health Beliefs and Blood Pressure Reduction in the DESERVE Study

Background There is growing recognition that positive health beliefs may promote blood pressure (BP) reduction, which is critical to stroke prevention but remains a persistent challenge. Yet, studies that examine the association between positive health beliefs and BP among stroke survivors are lacking. Methods and Results Data came from the DESERVE (Discharge Educational Strategies for Reduction of Vascular Events) study, a randomized controlled trial of a skills-based behavioral intervention to reduce vascular risk in a multiethnic cohort of 552 transient ischemic attack and mild/moderate stroke patients in New York City. The exposure was perception that people can protect themselves from having a stroke (ie, prevention self-efficacy) at baseline. The association between systolic BP (SBP) reduction at 12-month follow-up and self-efficacy was examined using linear regression adjusted for key confounders, overall and stratified by age, sex, race/ethnicity, and intervention trial arm. Approximately three quarters endorsed self-efficacy. These participants had, on average, 5.6 mm Hg greater SBP reduction compared with those who did not endorse it (95% CI, 0.5-10.7 mm Hg; P=0.032). Self-efficacy was significantly associated with greater SBP reduction, particularly among female versus male, younger versus older, and Hispanic versus non-Hispanic white patients. Sensitivity analysis adjusting for baseline SBP instead of elevated BP yielded no association between self-efficacy and SBP reduction, but showed sex differences in this association (women: β=5.3; 95% CI, -0.2 to 10.8; P=0.057; men: β=-3.3; 95% CI, -9.4 to 2.9; P=0.300; interaction P=0.064). Conclusions Self-efficacy was linked with greater SBP reduction among female stroke survivors. Targeted strategies to improve health beliefs after stroke may be important for risk factor management. REGISTRATION URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT01836354.

NADPH oxidase-mediated endothelial injury in HIV- and opioid-induced pulmonary arterial hypertension

We previously demonstrated that the combined exposure of human pulmonary microvascular endothelial cells (HPMECs) to morphine and viral protein(s) results in the oxidative stress-mediated induction of autophagy, leading to shift in the cells from early apoptotic to apoptosis-resistant proliferative status associated with the angioproliferative remodeling observed in pulmonary arterial hypertension (PAH). In this study, we tried to delineate the major source of HIV-1 protein Tat and morphine induced oxidative burst in HPMECs and its consequences on vascular remodeling and PAH in an in vivo model. We observed switch from the initial increased expression of NADPH oxidase (NOX) 2 in response to acute treatment of morphine and HIV-Tat to later increased expression of NOX4 on chronic treatment in the endoplasmic reticulum of HPMECs without any alterations in the mitochondria. Furthermore, NOX-dependent induction of autophagy was observed to play a pivotal role in regulating the endothelial cell survival. Our in vivo findings showed significant increase in pulmonary vascular remodeling, right ventricular systolic pressure, and Fulton index in HIV-transgenic rats on chronic administration of morphine. This was associated with increased oxidative stress in lung tissues and rat pulmonary microvascular endothelial cells. Additionally, endothelial cells from morphine-treated HIV-transgenic rats demonstrated increased expression of NOX2 and NOX4 proteins, inhibition of which ameliorated their increased survival upon serum starvation. In conclusion, this study describes NADPH oxidases as one of the main players in the oxidative stress-mediated endothelial dysfunction on the dual hit of HIV-viral protein(s) and opioids.

Sodium-hydrogen exchanger regulatory factor-1 (NHERF1) confers salt sensitivity in both male and female models of hypertension in aging

Hypertension is a risk factor for premature death and roughly 50% of hypertensive patients are salt-sensitive. The incidence of salt-sensitive hypertension increases with age. However, the mechanisms of salt-sensitive hypertension are not well understood. We had demonstrated decreased renal sodium‑hydrogen exchanger regulatory factor 1 (NHERF1) expression in old salt-resistant F344 rats. Based on those studies we hypothesized that NHERF1 expression is required for the development of some forms of salt-sensitive hypertension. To address this hypothesis, we measured blood pressure in NHERF1 expressing salt-sensitive 4-mo and 24-mo-old male and female Fischer Brown Norway (FBN) rats male and female 18-mo-old NHERF1 knock-out (NHERF1-/-) mice and wild-type (WT) littermates on C57BL/6J background after feeding high salt (8% NaCl) diet for 7 days. Our data demonstrate that 8% salt diet increased blood pressure in both male and female 24-mo-old FBN rats but not in 4-mo-old FBN rats and in 18-mo-old male and female WT mice but not in NHERF1-/- mice. Renal dopamine 1 receptor (D1R) expression was decreased in 24-mo-old rats, compared with 4-mo-old FBN rats. However, sodium chloride cotransporter (NCC) expression increased in 24-mo-old FBN rats. In FBN rats, age had no effect on NaK ATPase α1 and NKCC2 expression. By contrast, high salt diet increased the renal expressions of NKCC2, and NCC in 24-mo-old FBN rats. High salt diet also increased NKCC2 and NCC expression in WT mice but not NHERF1-/- mice. Our data suggest that renal NHERF1 expression confers salt sensitivity with aging, associated with increased expression of sodium transporters.

Perinatal taurine exerts a hypotensive effect in male spontaneously hypertensive rats and down-regulates endothelial oxide nitric synthase in the aortic arch

Essential hypertension is considered to be a result of the interaction between genetic and environmental factors, including perinatal factors. Different advantageous perinatal factors proved to have beneficial long-lasting effects against an abnormal genetic background. Taurine is a ubiquitous sulphur-containing amino acid present in foods such as seafood. The antihypertensive effects of taurine have been reported in experimental studies and in human hypertension. We aimed to investigate the effects of perinatal treatment with taurine in spontaneously hypertensive rats (SHR), a known model of genetic hypertension. Female SHR were administered with taurine (3 g/L) during gestation and lactation (SHR-TAU). Untreated SHR and Wistar-Kyoto rats (WKY) were used as controls. Long-lasting effects in offspring were investigated. Addition of taurine to the mother's drinking water reduced blood pressure in adult offspring. No differences were observed in cardiac hypertrophy. Findings on morphometric evaluations suggest that perinatal treatment with taurine would be partially effective in improving structural alterations of the aorta. Modifications in gene expression of Bcl-2 family members and upregulation of endothelial nitric oxide synthase in the aorta of 22-week-old male offspring were found. No differences were observed on relative telomere length in different cardiovascular tissues between SHR and SHR-TAU. Altogether results suggest that taurine programming, albeit sex specific, is associated with gene expression changes which ultimately may lead to improvement of aortic remodelling and enhanced endothelial function because of augmented nitric oxide (NO) production.

Sex and the kidneys: current understanding and research opportunities

Concerns regarding sex differences are increasingly pertinent in scientific and societal arenas. Although biological sex and socio-cultural gender are increasingly recognized as important modulators of renal function under physiological and pathophysiological conditions, gaps remain in our understanding of the mechanisms underlying sex differences in renal pathophysiology, disease development, progression and management. In this Perspectives article, we discuss specific opportunities for future research aimed at addressing these knowledge gaps. Such opportunities include the development of standardized core data elements and outcomes related to sex for use in clinical studies to establish a connection between sex hormones and renal disease development or progression, development of a knowledge portal to promote fundamental understanding of physiological differences between male and female kidneys in animal models and in humans, and the creation of new or the development of existing resources and datasets to make them more readily available for interrogation of sex differences. These ideas are intended to stimulate thought and interest among the renal research community as they consider sex as a biological variable in future research projects.

Menopause exacerbates visual dysfunction in experimental glaucoma

Glaucoma is the leading cause of irreversible blindness worldwide. Recently, estrogen deficiencies caused by early menopause, alterations in estrogen signaling via mutations in estrogen receptors, and polymorphisms along estrogen metabolic pathways have all been linked to an increased risk of developing glaucoma. Here, we examined how menopause and age impact visual function and retinal structure in an experimental model of glaucoma. Young (3-4 months) and aged (9-10 months) female Brown Norway rats were divided into pre- and post-menopausal cohorts by surgically inducing menopause via ovariectomy (OVX). After six weeks, ocular hypertension (OHT) was induced unilaterally for a period of eight weeks. Four cohorts were successfully followed to eight weeks: young sham (n = 8), young OVX (n = 9), aged sham (n = 10), and aged OVX (n = 11) animals. Intraocular pressure (IOP) was monitored weekly in all groups. Prior to inducing OHT (baseline) and at four and eight weeks after inducing OHT, we assessed visual acuity via the optomotor response (OMR) and retinal structure using optical coherence tomography (OCT). OHT decreased the OMR in all cohorts. We found that spatial frequency thresholds decreased by 54% in OVX animals after OHT compared to sham animals after OHT, regardless of age (p < 0.001). We also found thinning of the retinal nerve fiber layer (RNFL) and loss of total retinal thickness after induction of OHT. Aged animals had more thinning of the RNFL and loss of total retinal thickness compared to young animals (p < 0.001). Overall, OHT caused significant changes in visual function and retinal structure. Observing that OVX in young and aged animals further decreased spatial frequency thresholds after OHT suggests that an estrogen deficiency may intensify visual impairment after OHT.

Sex, Oxidative Stress, and Hypertension: Insights From Animal Models

One of the mechanisms responsible for blood pressure (BP) regulation is thought to be oxidative stress. In this review, we highlight preclinical studies that strongly support a role for oxidative stress in development and maintenance of hypertension in male animals, based on depressor responses to antioxidants, particularly tempol and apocynin. In females, oxidative stress seems to be important in the initial development of hypertension. However, whether maintenance of hypertension in females is mediated by oxidative stress is not clear. In clinical studies, pharmacological intervention to reduce BP with antioxidants has conflicting results, mostly negative. This review will discuss the uncertainties regarding blood pressure control and oxidative stress and potential reasons for these outcomes.

Oxidative Stress as Cause, Consequence, or Biomarker of Altered Female Reproduction and Development in the Space Environment

Oxidative stress has been implicated in the pathophysiology of numerous terrestrial disease processes and associated with morbidity following spaceflight. Furthermore, oxidative stress has long been considered a causative agent in adverse reproductive outcomes. The purpose of this review is to summarize the pathogenesis of oxidative stress caused by cosmic radiation and microgravity, review the relationship between oxidative stress and reproductive outcomes in females, and explore what role spaceflight-induced oxidative damage may have on female reproductive and developmental outcomes.

GPER blockers as Nox downregulators: A new drug class to target chronic non-communicable diseases

Oxidative stress is a hallmark of chronic non-communicable diseases such as arterial hypertension, coronary artery disease, diabetes, and chronic renal disease. Cardiovascular diseases are characterized by increased production of reactive oxygen species (ROS) by NAPDH oxidase 1 (Nox1) and additional Nox isoforms among other sources. Activation of the G protein-coupled estrogen receptor (GPER) can mediate multiple salutary effects on the cardiovascular system. However, GPER also has constitutive activity, e.g. in the absence of specific agonists, that was recently shown to promote hypertension and aging-induced tissue damage by promoting Nox1-derived production of ROS. Furthermore, the small molecule GPER blocker (GRB) G36 reduces blood pressure and vascular ROS production by selectively down-regulating Nox1 expression. These unexpected findings revealed GRBs as first in class Nox downregulators capable to selectively reduce the increased expression and activity of Nox1 in disease conditions. Here, we will discuss the paradigm shift from selective GPER activation to ligand-independent, constitutive GPER signaling as a key regulator of Nox-derived oxidative stress, and the surprising identification of GRBs as the first Nox downregulators for the treatment of chronic non-communicable diseases.

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.

The Risk Factors of High Blood Pressure among Young Adults in the Tujia-Nationality Settlement of China

Demographics questionnaires, and fitness tests were utilized to identify the risk factors of hypertension among younger adults in the years 2005, 2010, and 2014 in China's southwest province of Hubei. The results demonstrated that the prevalence of hypertension was higher between 2011 and 2014 among the young people in this area. The main risk factors of developing hypertension were found to be sex (as man), individuals over 40 years old, blue collar employees who worked in rural areas, overweight/obesity, and those with the low CRF.

Sex as a determinant of age-related changes in rat spinal cord inflammation-oxidation state

To close the gap in our knowledge of sex influence on age-related changes in inflammation-oxidation state in spinal cord (SC) relevant to inflammation/oxidative-stress associated neuropathologies, 2-3 month-old (young) and 18-20 month-old (old) rats, exhibiting increased level of IL-6, a commonly used marker of inflamm-aging, were examined for inflammatory/redox status, and the underlying regulatory networks' molecules expression. With age, rat SC microglia became sensitized ("primed"), while SC tissue shifted towards mild inflammatory state, with increased levels of proinflammatory IL-1β (key marker of microglial systemic inflammation-induced neurotoxicity), which was more prominent in males. This, most likely, reflected age- and sex-related impairment in the expression of CX3CR1, the receptor for fractalkine (CX3CL1), the soluble factor which regulates microglial activation and diminishes production of IL-1β (central for fractalkine neuroprotection). Considering that (i) age-related changes in SC IL-1β expression were not followed by complementary changes in SC IL-6 expression, and (ii) the reversal in the direction of the sex bias in circulating IL-6 level and SC IL-1β expression, it seems obvious that there are tissue-specific differences in the proinflammatory cytokine profile. Additionally, old male rat SC exhibited greater oxidative damage than female, reflecting, most likely, their lower capacity to maintain the pro-oxidant-antioxidant balance. In conclusion, these findings, apart from highlighting the significance of sex for age-associated changes in SC inflammation-oxidation, may be relevant for understating sex differences in human inflammation/oxidative-stress related SC diseases, and consequently, for optimizing their prevention/therapy.

T-cell involvement in sex differences in blood pressure control

Hypertension affects one-third of adults in the Western world and is the most common independent risk factor for cardiovascular disease, and the leading cause of premature death globally. Despite available therapeutic options, approximately half of the hypertensive population taking medication does not achieve adequate blood pressure (BP) control leaving them at increased risk of chronic kidney disease, renal failure, stroke, congestive heart failure, myocardial infarction, aneurysm and peripheral artery disease. New therapeutic options need to be identified for the treatment of hypertension in order to increase the percentage of individuals with controlled BP. There is a growing basic science literature regarding the role of T-cells in the pathogenesis of hypertension and BP control; however, the majority of this literature has been performed exclusively in males despite the fact that both men and women develop hypertension. This is especially problematic since hypertension is well recognized as having distinct sex differences in the prevalence, absolute BP values and molecular mechanisms contributing to the pathophysiology of the disease. The purpose of this article is to review the available literature regarding sex differences in T-cells in hypertension followed by highlighting the potential pathways that may result in sex-specific effects on T-cell activation and differentiation.

Sex-specific computational models of the spontaneously hypertensive rat kidneys: factors affecting nitric oxide bioavailability

The goals of this study were to 1) develop a computational model of solute transport and oxygenation in the kidney of the female spontaneously hypertensive rat (SHR), and 2) apply that model to investigate sex differences in nitric oxide (NO) levels in SHR and their effects on medullary oxygenation and oxidative stress. To accomplish these goals, we first measured NO synthase (NOS) 1 and NOS3 protein expression levels in total renal microvessels of male and female SHR. We found that the expression of both NOS1 and NOS3 is higher in the renal vasculature of females compared with males. To predict the implications of that finding on medullary oxygenation and oxidative stress levels, we developed a detailed computational model of the female SHR kidney. The model was based on a published male kidney model and represents solute transport and the biochemical reactions among O₂, NO, and superoxide ([Formula: see text]) in the renal medulla. Model simulations conducted using both male and female SHR kidney models predicted significant radial gradients in interstitial fluid oxygen tension (Po₂) and NO and [Formula: see text] concentration in the outer medulla and upper inner medulla. The models also predicted that increases in endothelial NO-generating capacity, even when limited to specific vascular segments, may substantially raise medullary NO and Po₂ levels. Other potential sex differences in SHR, including [Formula: see text] production rate, are predicted to significantly impact oxidative stress levels, but effects on NO concentration and Po₂ are limited.

The Efficacy of Perindopril/Amlodipine in Reaching Blood Pressure Targets: Results of the CONTROL Study

BACKGROUND

Inadequate blood pressure (BP) control remains a serious concern worldwide. Recent evidence suggests that the combination of a calcium channel blocker (CCB) with an angiotensin-converting enzyme inhibitor (ACEi) in patients with essential hypertension provides effective BP control with decreased adverse cardiac and renal events.

OBJECTIVES

This study was designed to quantitatively evaluate the efficacy and tolerability of a fixed dose combination of perindopril and amlodipine in the Kingdom of Saudi Arabia on a population of patients with essential hypertension, as well as to identify the predictors of BP control in this population.

METHODS

This was an observational, multicenter, open-label cohort study of patients with essential hypertension with or without diabetes mellitus, treated with a fixed dose combination of perindopril and amlodipine. Patients were followed up in four-week intervals for a total of 12 weeks. They were initially started on the lowest dose of the ACEi/CCB combination and up-titrated at each follow-up according to their response to treatment. The primary end-point of the study was the percentage of patients with controlled BP at study termination (week 12).

RESULTS

A total of 1996 patients completed the study. Both systolic blood pressure (SBP) and diastolic blood pressure (DBP) control was observed in 93.3% of patients at week 12. As for the predictors of BP control, it was found that female gender was associated with more BP control [odds ratio (OR) = 1.76, 95% CI: 1.14-2.70, p value = 0.01], whereas older age was associated with less BP control (OR = 0.98, 95% CI: 0.96-1.00, p value = 0.02). Similarly, having type I and type II diabetes mellitus was also associated with less BP control (OR = 0.19, 95% CI: 0.08-0.45, p < 0.0001 and OR = 0.33, 95% CI: 0.22-0.48, p < 0.0001, respectively). In a qualitative assessment, both investigators and patients perceived efficacy and tolerability of perindopril/amlodipine to be excellent.

CONCLUSION

We found that a fixed combination of perindopril/amlodipine is effective in controlling BP in patients with essential hypertension, with older age, male gender, and diabetes mellitus being independent risk factors for less BP control.

Diseases and Aging: Gender Matters

At first glance, biological differences between male and female sex seem obvious, but, in fact, they affect a vast number of deeper levels apart from reproductive function and related physiological features. Such differences affect all organizational levels including features of cell physiology and even functioning of separate organelles, which, among other things, account for such global processes as resistance to diseases and aging. Understanding of mechanisms underlying resistance of one of the sexes to pathological processes and aging will allow taking into consideration gender differences while developing drugs and therapeutic approaches, and it will provide an opportunity to reproduce and enhance such resistance in the more vulnerable gender. Here we review physiological as well as cellular and biological features of disease course including aging that are affected by gender and discuss potential mechanisms behind these processes. Such mechanisms include features of oxidative metabolism and mitochondrial functioning.

Chronic Blockade of the Androgen Receptor Abolishes Age-Dependent Increases in Blood Pressure in Female Growth-Restricted Rats

Intrauterine growth restriction induced via placental insufficiency programs a significant increase in blood pressure at 12 months of age in female growth-restricted rats that is associated with early cessation of estrous cyclicity, indicative of premature reproductive senescence. In addition, female growth-restricted rats at 12 months of age exhibit a significant increase in circulating testosterone with no change in circulating estradiol. Testosterone is positively associated with blood pressure after menopause in women. Thus, we tested the hypothesis that androgen receptor blockade would abolish the significant increase in blood pressure that develops with age in female growth-restricted rats. Mean arterial pressure was measured in animals pretreated with and without the androgen receptor antagonist, flutamide (8 mg/kg/day, SC for 2 weeks). Flutamide abolished the significant increase in blood pressure in growth-restricted rats relative to control at 12 months of age. To examine the mechanism(s) by which androgens contribute to increased blood pressure in growth-restricted rats, blood pressure was assessed in rats untreated or treated with enalapril (250 mg/L for 2 weeks). Enalapril eliminated the increase in blood pressure in growth-restricted relative to vehicle- and flutamide-treated controls. Furthermore, the increase in medullary angiotensin type 1 receptor mRNA expression was abolished in flutamide-treated growth-restricted relative to untreated counterparts and controls; cortical angiotensin-converting enzyme mRNA expression was reduced in flutamide-treated growth-restricted versus untreated counterparts. Thus, these data indicate that androgens, via activation of the renin-angiotensin system, are important mediators of increased blood pressure that develops by 12 months of age in female growth-restricted rats.

Chemosensory Communication of Gender Information: Masculinity Bias in Body Odor Perception and Femininity Bias Introduced by Chemosignals During Social Perception

Human body odor is a source of important social information. In this study, we explore whether the sex of an individual can be established based on smelling axillary odor and whether exposure to male and female odors biases chemosensory and social perception. In a double-blind, pseudo-randomized application, 31 healthy normosmic heterosexual male and female raters were exposed to male and female chemosignals (odor samples of 27 heterosexual donors collected during a cardio workout) and a no odor sample. Recipients rated chemosensory samples on a masculinity-femininity scale and provided intensity, familiarity and pleasantness ratings. Additionally, the modulation of social perception (gender-neutral faces and personality attributes) and affective introspection (mood) by male and female chemosignals was assessed. Male and female axillary odors were rated as rather masculine, regardless of the sex of the donor. As opposed to the masculinity bias in the odor perception, a femininity bias modulating social perception appeared. A facilitated femininity detection in gender-neutral faces and personality attributes in male and female chemosignals appeared. No chemosensory effect on mood of the rater was observed. The results are discussed with regards to the use of male and female chemosignals in affective and social communication.

Disruption of the cytochrome P-450 1B1 gene exacerbates renal dysfunction and damage associated with angiotensin II-induced hypertension in female mice

Recently, we demonstrated in female mice that protection against ANG II-induced hypertension and associated cardiovascular changes depend on cytochrome P-450 (CYP)1B1. The present study was conducted to determine if Cyp1b1 gene disruption ameliorates renal dysfunction and organ damage associated with ANG II-induced hypertension in female mice. ANG II (700 ng·kg(-1)·min(-1)) infused by miniosmotic pumps for 2 wk in female Cyp1b1(+/+) mice did not alter water consumption, urine output, Na(+) excretion, osmolality, or protein excretion. However, in Cyp1b1(-/-) mice, ANG II infusion significantly increased (P < 0.05) water intake (5.50 ± 0.42 ml/24 h with vehicle vs. 8.80 ± 0.60 ml/24 h with ANG II), urine output (1.44 ± 0.37 ml/24 h with vehicle vs. 4.30 ± 0.37 ml/24 h with ANG II), and urinary Na(+) excretion (0.031 ± 0.016 mmol/24 h with vehicle vs. 0.099 ± 0.010 mmol/24 h with ANG II), decreased osmolality (2,630 ± 79 mosM/kg with vehicle vs. 1,280 ± 205 mosM/kg with ANG II), and caused proteinuria (2.60 ± 0.30 mg/24 h with vehicle vs. 6.96 ± 0.55 mg/24 h with ANG II). Infusion of ANG II caused renal fibrosis, as indicated by an accumulation of renal interstitial α-smooth muscle actin, collagen, and transforming growth factor-β in Cyp1b1(-/-) but not Cyp1b1(+/+) mice. ANG II also increased renal production of ROS and urinary excretion of thiobarburic acid-reactive substances and reduced the activity of antioxidants and urinary excretion of nitrite/nitrate and the 17β-estradiol metabolite 2-methoxyestradiol in Cyp1b1(-/-) but not Cyp1b1(+/+) mice. These data suggest that Cyp1b1 plays a critical role in female mice in protecting against renal dysfunction and end-organ damage associated with ANG II-induced hypertension, in preventing oxidative stress, and in increasing activity of antioxidant systems, most likely via generation of 2-methoxyestradiol from 17β-estradiol.

Sex differences in the developmental origins of cardiovascular disease

The Developmental Origins of Health and Disease (DOHaD) proposes that adverse events during early life program an increased risk for cardiovascular disease. Experimental models provide proof of concept but also indicate that insults during early life program sex differences in adult blood pressure and cardiovascular risk. This review will highlight the potential mechanisms that contribute to the etiology of sex differences in the developmental programming of cardiovascular disease.

Effects of the use of assisted reproductive technologies and an obesogenic environment on resistance artery function and diabetes biomarkers in mice offspring

Maternal obesity affects the incidence of cardiovascular disease and diabetes in offspring. Also the use of assisted reproductive technologies (ART) has been associated with cardiovascular deficiencies in offspring. Obese women often suffer from infertility and use ART to achieve a pregnancy, but the combined effects of maternal obesity and ART on cardiovascular health and incidence of diabetes in the offspring is not known. Here, we report the effects of the use of ART within an obesogenic environment, consisting of feeding a western diet (WD) to dams and offspring, on resistance artery function and presence of diabetes biomarkers in juvenile mice offspring. Our results indicate that WD and ART interacted to induce endothelial dysfunction in mesenteric resistance arteries isolated from 7-week-old mice offspring. This was determined by presence of a reduced acetylcholine-induced dilation compared to controls. The arteries from these WD-ART mice also had greater wall cross-sectional areas and wall to lumen ratios indicative of vascular hypertrophic remodeling. Of the diabetes biomarkers measured, only resistin was affected by a WD×ART interaction. Serum resistin was significantly greater in WD-ART offspring compared to controls. Diet and sex effects were observed in other diabetes biomarkers. Our conclusion is that in mice the use of ART within an obesogenic environment interacts to favor the development of endothelial dysfunction in the resistance arteries of juvenile offspring, while having marginal effects on diabetes biomarkers.

Need for gender-specific pre-analytical testing: the dark side of the moon in laboratory testing

Many international organisations encourage studies in a sex-gender perspective. However, research with a gender perspective presents a high degree of complexity, and the inclusion of sex-gender variable in experiments presents many methodological questions, the majority of which are still neglected. Overcoming these issues is fundamental to avoid erroneous results. Here, pre-analytical aspects of the research, such as study design, choice of utilised specimens, sample collection and processing, animal models of diseases, and the observer's role, are discussed. Artefacts in this stage of research could affect the predictive value of all analyses. Furthermore, the standardisation of research subjects according to their lifestyles and, if female, to their life phase and menses or oestrous cycle, is urgent to harmonise research worldwide. A sex-gender-specific attention to pre-analytical aspects could produce a decrease in the time for translation from the bench to bedside. Furthermore, sex-gender-specific pre-clinical pharmacological testing will enable adequate assessment of pharmacokinetic and pharmacodynamic actions of drugs and will enable, where appropriate, an adequate gender-specific clinical development plan. Therefore, sex-gender-specific pre-clinical research will increase the gender equity of care and will produce more evidence-based medicine.

Effect of progressive muscle relaxation in female health care professionals

BACKGROUND

Increasing population, fast paced industrialization, increased, competitiveness, unanticipated problems in the work place have increased the stress among the females working in health care in recent times.

AIM

The aim of the following study is to detect the stress levels among female health care professionals in the age group of 25-35 years and its impact on health.

SUBJECTS AND METHODS

A prospective cross-sectional pilot project was conducted in a tertiary care hospital in Eastern part of India, after receiving approval from the Institutional Ethics Committee and informed consent form was taken from the subjects. Stress level in the subjects was assessed according to the presumptive life event stress scale. Females with scores above 200 were selected. For these, initial assessment of anthropometric measurement, electrocardiogram and lipid profile analysis, resting pulse rate, blood pressure, physical fitness index (PFI), breath holding time (BHT), isometric hand grip (IHG) test results were evaluated and recorded. All subjects were given training of progressive muscle relaxation (PMR) for 3 months. After 3 months, the lipid profile and vital parameters, Perceived Stress Scale values were re-evaluated and subjects were asked to repeat the same exercises and data thus recorded were analyzed using Statistical Package for the Social Sciences (SPSS) version 16 (SPSS Inc. Released 2007. SPSS for Windows, Version 16.0. Chicago, SPSS Inc.).

RESULTS

Significant decrease in resting heart rate, blood pressure and Perceived Stress Scale levels was seen after PMR training in the subjects. Results of BHT, IHG tests and PFI were significantly increased after PMR training. There was a significant decrease in total cholesterol, triglyceride and low-density lipoprotein cholesterol in subjects after practicing PMR for 3 months.

CONCLUSIONS

Increasing stress among female health care professionals is a cause for concern and there is a need to adopt early life-style modification by practicing relaxation exercises to ameliorate stress and to improve not only their quality-of-life in general, but patient care in particular.

Effects of biological sex on the pathophysiology of the heart

Cardiovascular diseases are the leading causes of death in men and women in industrialized countries. While the effects of biological sex on cardiovascular pathophysiology have long been known, the sex-specific mechanisms mediating these processes have been further elucidated over recent years. This review aims at analysing the sex-based differences in cardiac structure and function in adult mammals, and the sex-based differences in the main molecular mechanisms involved in the response of the heart to pathological situations. It emerged from this review that the sex-based difference is a variable that should be dealt with, not only in basic science or clinical research, but also with regards to therapeutic approaches.

Folate administration decreases oxidative status and blood pressure in postmenopausal women

PURPOSE

The purpose of this study was to evaluate whether folate exerts antioxidant effects in postmenopausal women and whether this effect is related to folate-induced modification of 24-h ambulatory blood pressure (BP).

METHODS

Double-blind placebo-controlled study performed in 30 apparently healthy postmenopausal women recruited at the outpatient service of University Hospital. Women, free from hormones or substances possibly interfering with the investigated parameters, were randomized to receive orally for 3 weeks placebo (n = 15) or 15 mg/day of 5-methyltetrahydrofolate (5-MTHF; n = 15). Whole-blood free oxygen radicals test (FORT), free oxygen radical defence (FORD), lipids, glucose, insulin, insulin resistance [homeostatic model assessment for insulin resistance (HOMA-IR)], homocysteine and 24-h ambulatory BP values were evaluated.

RESULTS

In the entire group of women, FORT was independently and inversely related to the day-night difference of diastolic (r = 0.420; p = 0.03) and mean BP (r = 0.497; p = 0.01). Placebo did not affect any biochemical or BP parameter. 5-MTHF reduced FORT (-71.5 ± 98.2; p = 0.02) and increased FORD (0.5 ± 0.9; p = 0.05), decreased insulin (p = 0.01), HOMA-IR (p = 0.0002) and homocysteine (p = 0.008). During 5-MTHF, night-time mean (p = 0.001) and diastolic BP (p = 0.002) decreased of about 5 mmHg and the day-night difference of mean (p = 0.001) and diastolic BP (p = 0.002) contemporaneously increased. FORT reduction was related to the amplification of the nocturnal decline of mean (0.697; p = 0.006) and diastolic BP (r = 0.777; p = 0.002) and to the amplification of the day-night difference of diastolic BP (r = 0.63; p = 0.015).

CONCLUSIONS

Present data show a clear reduction of oxidative stress during 5-MTHF administration and a strong correlation between this decrease and the nocturnal decline of BP. The possible link between the two is worthy to be explored.

Estrogen metabolism by cytochrome P450 1B1 modulates the hypertensive effect of angiotensin II in female mice

To determine the role of cytochrome P450 (CYP) 1B1 in the sex difference in response to angiotensin II (Ang II)-induced hypertension, female Cyp1b1(+/+) and Cyp1b1(-/-) mice were infused with Ang II (700 ng/kg per minute) or vehicle with or without ovariectomy. In addition, mice were treated with the CYP1B1 inhibitor, 2,3',4,5'-tetramethoxystilbene (TMS; 300 μg/kg IP, every third day), and 17-β estradiol metabolites, 2-hydroxyestradiol (2-OHE), 4-OHE, or 2-methoxyestradiol (1.5 mg/kg per day IP, for 2 weeks) and systolic blood pressure (SBP) measured. Ang II increased SBP more in Cyp1b1(-/-) than in Cyp1b1(+/+) mice (119±3-171±11 versus 120±4-149±4 mm Hg; P<0.05). Ang II caused cardiovascular remodeling and endothelial dysfunction and increased vascular reactivity and oxidative stress in Cyp1b1(-/-) but not in Cyp1b1(+/+)mice. The Ang II-induced increase in SBP was enhanced by ovariectomy and TMS in Cyp1b1(+/+) but not in Cyp1b1(-/-) mice. 2-OHE did not alter Ang II-induced increase in SBP in Cyp1b1(+/+) mice but minimized it in Cyp1b1(-/-) mice, whereas 4-OHE enhanced Ang II-induced increase in SBP in Cyp1b1(+/+) mice but did not alter the increased SBP in Cyp1b1(-/-) mice. 2-OHE-derived catechol-O-methyltransferase metabolite, 2-methoxyestradiol, inhibited Ang II-induced increase in SBP in Cyp1b1(-/-) mice. Ang II increased plasma levels of 2-methoxyestradiol in Cyp1b1(+/+) but not in Cyp1b1(-/-) mice and increased activity of cardiac extracellular signal-regulated kinase 1/2, p38 mitogen-activated kinase, c-Src, and Akt in Cyp1b1(-/-) but not in Cyp1b1(+/+) mice. These data suggest that CYP1B1 protects against Ang II-induced hypertension and associated cardiovascular changes in female mice, most likely mediated by 2-methoxyestradiol-inhibiting oxidative stress and the activity of these signaling molecules.

Age-related alterations of plasma glutathione and oxidation of redox potentials in chimpanzee (Pan troglodytes) and rhesus monkey (Macaca mulatta)

Chimpanzee (Pan troglodytes) and rhesus macaque (Macaca mulatta) and humans (Homo sapiens) share physiological and genetic characteristics, but have remarkably different life spans, with chimpanzees living 50-60 % and the rhesus living 35-40 % of maximum human survival. Since oxidative processes are associated with aging and longevity, we might expect to see species differences in age-related oxidative processes. Blood and extracellular fluid contain two major thiol redox nodes, glutathione (GSH)/glutathione-disulfide (GSSG) and cysteine (Cys)/cystine (CySS), which are subject to reversible oxidation-reduction reactions and are maintained in a dynamic non-equilibrium state. Disruption of these thiol redox nodes leads to oxidation of their redox potentials (EhGSSG and EhCySS) which affects cellular physiology and is associated with aging and the development of chronic diseases in humans. The purpose of this study was to measure age-related changes in these redox thiols and their corresponding redox potentials (Eh) in chimpanzees and rhesus monkeys. Our results show similar age-related decreases in the concentration of plasma GSH and Total GSH as well as oxidation of the EhGSSG in male and female chimpanzees. Female chimpanzees and female rhesus monkeys also were similar in several outcome measures. For example, similar age-related decreases in the concentration of plasma GSH and Total GSH, as well as age-related oxidation of the EhGSSG were observed. The data collected from chimpanzees and rhesus monkeys corroborates previous reports on oxidative changes in humans and confirms their value as a comparative reference for primate aging.

Association of inflammatory and oxidative stress biomarkers in subjects with cardiovascular risk

Cardiovascular disease is originated in the vascular endothelium, which controls the homeostasis and the filtration and diffusion of molecules from blood to the tissues. The classical cardiovascular risk factors (CRFs) act directly on the endothelium through an increase in the production of reactive oxygen species, promoting an endothelial activation mediated by the expression of adhesion and proinflammatory molecules, which lead to endothelial dysfunction, the progression of the atherosclerotic plaque, and the onset of cardiovascular disease. The objective of this study was to analyze the association of superoxide dismutase, catalase, gluthatione peroxidase, and lipoperoxidation with fibrinogen, interleukin (IL)-6, tumor necrosis factor-α, and vascular cell adhesion molecule (VCAM)-1 in subjects with cardiovascular risk (CVR) and CRF. This was a cross-sectional study of 114 individuals; oxidative stress (superoxide dismutase, catalase, gluthatione peroxidase, and lipoperoxidation) and inflammatory (fibrinogen, IL-6, tumor necrosis factor-α, and VCAM-1) biomarkers were measured; a CVR score (Framingham) and its CRF were taken into consideration to classify the participants. Twenty-nine subjects out of a total of 114 had high CVR. Smokers and subjects with diabetes (43 subjects) were excluded from the low CVR group. Significant decreases in lipoperoxidation, IL-6, and VCAM-1 and an increase in SOD were found in the high CVR group (P ≤ 0.05). Individual analysis of each CRF in the 114 subjects revealed a different pattern in the biomarkers' statistical differences. Concluding that the biomarkers show statistical differences in each CRF, especially IL-6, VCAM-1, and SOD; therefore, these are highly recommended to be used as biomarkers of the oxidative stress and inflammatory status in CVR.

The effects of gender difference on monocrotaline-induced pulmonary hypertension in rats

The present study aimed to compare the effect of gender difference on hemodynamic consequences in the development of monocrotaline (MCT)-induced pulmonary hypertension in rat. The effect of antioxidant enzyme systems on the development of pulmonary hypertension mediated by the phytotoxin MCT and the effect of gender on these antioxidant systems were also investigated. For this purpose, the right ventricular pressures (RVPs) and right ventricular/heart weight (HW) ratios were compared between groups and the glutathione (GSH) level and superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) activities were determined in lung and liver tissue samples of rats. RVP and right ventricular/HW ratios significantly increased in the MCT group compared to the control group. In the MCT group, RVP was significantly higher in males than females. MCT-induced pulmonary hypertension resulted in decreased GSH level, decreased GST and SOD activities and increased CAT activity in lung and liver tissues of both male and female rats. In addition, the lung and liver GSH level and GST and SOD levels were higher in female control rats compared to male control rats. The results of the present study, that antioxidant enzyme activities were different between the groups, highlight the possible role of oxidative stress in the pathogenesis of MCT-induced pulmonary hypertension in rats. Moreover, the lower antioxidant defense capacity of male rats than female rats may be considered as a cause of more aggressive course of MCT-induced pulmonary hypertension in males compared to females.

Circulating cell-free DNA is associated with cardiometabolic risk factors: the Health 2000 Survey

Cell-free circulating DNA (cf-DNA) has recently arisen as a promising biomarker in acute cardiovascular pathologies and as a mortality predictor in myocardial infarction. We wanted to investigate whether the baseline cf-DNA concentration could serve as an indicator of increased cardiovascular risk and early atherosclerosis. The study population consisted of 1337 participants (aged 46-77 years) in the Health 2000 Survey. cf-DNA was quantified directly in plasma using the fluorescence-based Quant-iT™ high-sensitivity DNA assay kit. Increased cf-DNA levels paralleled a cluster of cardiometabolic risk factors, such as high blood pressure, unfavorable lipid metabolism profile and systemic inflammation in both sexes. In addition, higher cf-DNA levels indicated decreased arterial elasticity and glucose intolerance in women not using hormonal replacement therapy (HRT). The cf-DNA level was also observed to be an independent determinant for Young's elastic modulus but not for carotid artery compliance or beta stiffness index in the women not using HRT. Hence, we conclude that cf-DNA could serve as an auxiliary biomarker in cardiometabolic risk assessment and as an indicator of arterial stiffness in women not using HRT.

Hypertension: what's sex got to do with it?

Hypertension is a complex and multifaceted disease, and there are well established sex differences in many aspects of blood pressure (BP) control. The intent of this review is to highlight recent work examining sex differences in the molecular mechanisms of BP control in hypertension to assess whether the "one-size-fits-all" approach to BP control is appropriate with regard to sex.

Pregnancy Complications and Later Development of Hypertension

Pregnancy complications such as preeclampsia and diabetes affect approximately 5 to 10 % of all pregnancies and compromise maternal and fetal health during gestation. Complications during pregnancy may also contribute to the development of hypertension and future cardiovascular risk in the mother. Moreover, fetal exposure to hypertension and diabetes during pregnancy can program hypertension and cardiovascular disease in the offspring. Transgenerational transmission of programmed cardiovascular risk highlights the importance of understanding the mechanisms that link complications during pregnancy with later hypertension in her offspring and subsequent generations. However, experimental studies are needed to investigate the cause and effect of increased blood pressure in the mother following a complicated pregnancy and provide insight into the development of preventative measures that may improve the long-term cardiovascular health of women and their offspring.

Sex differences in the enhanced responsiveness to acute angiotensin II in growth-restricted rats: role of fasudil, a Rho kinase inhibitor

This study tested the hypothesis that Rho kinase contributes to the enhanced pressor response to acute angiotensin II in intact male growth-restricted and gonadectomized female growth-restricted rats. Mean arterial pressure (MAP) and renal function were determined in conscious animals pretreated with enalapril (250 mg/l in drinking water) for 1 wk to block the endogenous renin-angiotensin system and normalize blood pressure (baseline). Blood pressure and renal hemodynamics did not differ at baseline. Acute Ang II (100 ng·kg(-1)·min(-1)) induced a greater increase in MAP and renal vascular resistance and enhanced reduction in glomerular filtration rate in intact male growth-restricted rats compared with intact male controls (P < 0.05). Cotreatment with the Rho kinase inhibitor fasudil (33 μg·kg(-1)·min(-1)) significantly attenuated these hemodynamic changes (P < 0.05), but it did not abolish the differential increase in blood pressure above baseline, suggesting that the impact of intrauterine growth restriction on blood pressure in intact male growth-restricted rats is independent of Rho kinase. Gonadectomy in conjunction with fasudil returned blood pressure back to baseline in male growth-restricted rats, and yet glomerular filtration rate remained significantly reduced (P < 0.05). Thus, these data suggest a role for enhanced renal sensitivity to acute Ang II in the developmental programming of hypertension in male growth-restricted rats. However, inhibition of Rho kinase had no effect on the basal or enhanced increase in blood pressure induced by acute Ang II in the gonadectomized female growth-restricted rat. Therefore, these studies suggest that Rho kinase inhibition exerts a sex-specific effect on blood pressure sensitivity to acute Ang II in growth-restricted rats.

Potentiation of vascular oxidative stress and nitric oxide-mediated endothelial dysfunction by high-fat diet in a mouse model of estrogen deficiency and hyperandrogenemia

Estrogen deficiency is associated with increased cardiovascular risk due, in part, to hypertension, endothelial dysfunction, obesity, and hypercholesterolemia. Underlying mechanisms for this remain unclear. Here, we investigated whether high-fat intake aggravates vascular dysfunction through oxidative stress and inflammation, which could predispose to cardiovascular injury in conditions of estrogen deficiency, such as menopause. We studied female homozygous follitropin receptor knock out (FORKO) mice, which have hormonal features of clinical menopause and hypertension and wild-type (WT) and heterozygote mice (HTZ), fed a standard or high-fat diet for 4 months. Vascular function and structure were evaluated in arterial segments by pressurized myography. Acetylcholine (ACh)-induced vasodilation was reduced in FORKO vs. WT mice (P < .001). N(varpi)-nitro-l-arginine-methyl-ester inhibited Ach-induced relaxation in all groups on normal chow and in WT and HTZ on high-fat diet (FD) but had no effect in fat-fed FORKO mice. Antioxidant cocktail (superoxide dismutase, catalase, Tempol) increased ACh responses only in high-fat diet FORKO mice (P < .05). Vascular media-to-lumen ratio was increased and reactive oxygen species (ROS) generation, nitrotyrosine formation, and plasma nitrite levels were augmented in fat-fed FORKO vs. FORKO on normal chow. High-fat diet did not influence vascular inflammatory responses in any group. Our data demonstrate that FORKO mice have altered nitric oxide-sensitive vasorelaxation and vascular remodeling, which are aggravated by high-fat diet. Underlying mechanisms for this may involve decreased NO formation and increased generation of ROS and nitrotyrosine. These findings suggest that high-fat intake potentiates vascular damage in estrogen-deficient states, an effect involving increased oxidative stress.