Sex differences in angiotensin II responses contribute to a differential regulation of cox-mediated vascular dysfunction during aging

Sex-associated differences in cardiac ageing: Clinical aspects and molecular mechanisms

Despite the extensive clinical and scientific advances in prevention, diagnostics and treatment, cardiovascular diseases (CVD) remain the leading cause of morbidity and mortality worldwide for people aged 65 and over. Of all ageing-related diseases, CVD are responsible for almost one-third of deaths in the elderly, being above all cancers combined. Age is an independent and unavoidable risk factor contributing to the impairment of heart and blood vessels. As the average age of the population in industrialized countries has doubled in the last century, and almost a fifth of the world's population is predicted to be over 65 in the next decade, we can assume that the burden of CVD will fall primarily on the elderly. Evidence from basic and clinical science has shown that sex significantly influences the onset and severity of CVD. In women, CVD usually develop later than in men and with atypical symptomatology. After menopause, however, the incidence and severity of CVD increase in women, reaching equality in both sexes. Although intrinsic sexual dimorphism in cardiovascular ageing may contribute to the sex differences in CVD progression, the molecular mechanisms associated with cardiovascular ageing and their clinical value are not known in detail. In this review, we discuss the scientific knowledge available, focusing on structural, hormonal, genetic/epigenetic and inflammatory pathways, seeking to transfer these findings to the cardiovascular clinic in terms of prevention, diagnosis, prognosis and management of these pathologies and proposing possible validation of target specifics.

Age- and Gender-Related Differences in Renal Vascular Responses to Angiotensin II in Rats: The Role of the Mas Receptor

Background

Renal hemodynamic is influenced by both gender difference and age. Also, the Mas receptor (MasR) as one of the depressor components of the renin-angiotensin system which has more expression in females could postpone some dysfunctions associated with age, although the association between MasR and age in renal vascular responses to angiotensin II (Ang II) in male and female rats was well undefined. Therefore, the current study examined the effects of age and sex on systemic and renal vascular responses to graded doses of Ang II in Wistar rats with or without MasR antagonists (A779).

Materials and Methods

Anesthetized Wistar male and female rats with two age ranges of 8-12 and 24-28 weeks were exposed to cannulate venous and arterial vessels. After stability, mean arterial pressure (MAP), renal perfusion pressure (RPP), renal vascular resistance (RVR), and renal blood flow (RBF) were measured in response to the infusion of Ang II with or without A779.

Results

There were no significant differences in the base values of MAP, RPP, RBF, and RVR between the two genders in both the age ranges of 8-12 and 24-28 weeks. In addition, no significant gender difference was observed in the age ranges of the above mentioned parameters among the groups receiving vehicle or A779. Also, the infusion of vehicle or A779 could not significantly change the base values. On the other hand, the responses of RBF and RVR to Ang II revealed gender differences among 8-12-week groups (P < 0.05) but not in 24-28-week groups, while the blockade of MasR could not influence the responses in the age ranges.

Conclusion

It was concluded that age could impress sex difference in RBF and RVR responses to Ang II infusion and that MasR alone could not participate in these responses. In other words, MasR is not active under normal and acutely elevated Ang II levels.

Impact of Sex and Exercise on Femoral Artery Function: More Favorable Adaptation in Male Rats

Blood flow increases in arteries of the skeletal muscles involved in active work. Our aim was to investigate the gender differences as a result of adaptation to sport in the femoral arteries. Vascular reactivity and histology of animals were compared following a 12-week swimming training. Animals were divided into sedentary male (MS), trained male (MTr), sedentary female (FS), and trained female (FTr) groups. Isolated femoral artery rings were examined by wire myography. Contraction induced by phenylephrine (Phe) did not differ between the four groups. The contractile ability in the presence of indomethacin (INDO) was decreased in both sedentary groups. However, we found a specific cyclooxygenase-2 (COX-2) role only in FS rats. After exercise training, we observed increased vasoconstriction in both sexes, when nitro-L-arginine methyl ester (L-NAME) was present. The COX-dependent vasoconstriction effect disappeared in MTr animals, and the COX-2-dependent vasoconstriction effect disappeared in FTr ones. Relaxation was reduced significantly, when L-NAME was present in MTr animals compared to in FTr rats. The training was associated with greater endothelial nitric oxide synthase (eNOS) protein expression in males, but not in females. The present study proves that there are gender differences regarding adaptation mechanisms of musculocutaneous arteries to sports training. In males, relaxation reserve capacity was markedly elevated compared to in females.

Vascular Aging in Rodent Models: Contrasting Mechanisms Driving the Female and Male Vascular Senescence

Increasing scientific interest has been directed to sex as a biological and decisive factor on several diseases. Several different mechanisms orchestrate vascular function, as well as vascular dysfunction in cardiovascular and metabolic diseases in males and females. Certain vascular sex differences are present throughout life, while others are more evident before the menopause, suggesting two important and correlated drivers: genetic and hormonal factors. With the increasing life expectancy and aging population, studies on aging-related diseases and aging-related physiological changes have steeply grown and, with them, the use of aging animal models. Mouse and rat models of aging, the most studied laboratory animals in aging research, exhibit sex differences in many systems and physiological functions, as well as sex differences in the aging process and aging-associated cardiovascular changes. In the present review, we introduce the most common aging and senescence-accelerated animal models and emphasize that sex is a biological variable that should be considered in aging studies. Sex differences in the cardiovascular system, with a focus on sex differences in aging-associated vascular alterations (endothelial dysfunction, remodeling and oxidative and inflammatory processes) in these animal models are reviewed and discussed.

Candesartan could ameliorate the COVID-19 cytokine storm

BACKGROUND

Angiotensin receptor blockers (ARBs) reducing inflammation and protecting lung and brain function, could be of therapeutic efficacy in COVID-19 patients.

METHODS

Using GSEA, we compared our previous transcriptome analysis of neurons injured by glutamate and treated with the ARB Candesartan (GSE67036) with transcriptional signatures from SARS-CoV-2 infected primary human bronchial epithelial cells (NHBE) and lung postmortem (GSE147507), PBMC and BALF samples (CRA002390) from COVID-19 patients.

RESULTS

Hundreds of genes upregulated in SARS-CoV-2/COVID-19 transcriptomes were similarly upregulated by glutamate and normalized by Candesartan. Gene Ontology analysis revealed expression profiles with greatest significance and enrichment, including proinflammatory cytokine and chemokine activity, the NF-kappa B complex, alterations in innate and adaptive immunity, with many genes participating in the COVID-19 cytokine storm.

CONCLUSIONS

There are similar injury mechanisms in SARS-CoV-2 infection and neuronal injury, equally reduced by ARB treatment. This supports the hypothesis of a therapeutic role for ARBs, ameliorating the COVID-19 cytokine storm.

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.

Crosstalk between Peripheral Small Vessel Properties and Anxious-like Profiles: Sex, Genotype, and Interaction Effects in Mice with Normal Aging and 3×Tg-AD mice at Advanced Stages of Disease

Cardiovascular disease resulting from oxidative stress and inflammation can exacerbate Alzheimer's disease. This brief report provides the first evidence of compromised small peripheral mesenteric resistance artery (MRA) properties in 15-month-old 3xTg-AD mice. Females showed worse physiologically relevant MRA structural (increased passive external and internal diameters, cross sectional area) and functional (increased active internal diameters) alterations suggesting sex-dependent dysfunctions. At both physiological and high intraluminal pressures, vascular alterations correlated with the anxious-like behavioral profile, in a sex-dependent manner. Finally, the results unveil a crosstalk between peripheral small vessel properties and behavior in both 3xTg-AD mice and age-matched counterparts with normal aging.

Stroke and the neurovascular unit: glial cells, sex differences, and hypertension

A functional neurovascular unit (NVU) is central to meeting the brain's dynamic metabolic needs. Poststroke damage to the NVU within the ipsilateral hemisphere ranges from cell dysfunction to complete cell loss. Thus, understanding poststroke cell-cell communication within the NVU is of critical importance. Loss of coordinated NVU function exacerbates ischemic injury. However, particular cells of the NVU (e.g., astrocytes) and those with ancillary roles (e.g., microglia) also contribute to repair mechanisms. Epidemiological studies support the notion that infarct size and recovery outcomes are heterogeneous and greatly influenced by modifiable and nonmodifiable factors such as sex and the co-morbid condition common to stroke: hypertension. The mechanisms whereby sex and hypertension modulate NVU function are explored, to some extent, in preclinical laboratory studies. We present a review of the NVU in the context of ischemic stroke with a focus on glial contributions to NVU function and dysfunction. We explore the impact of sex and hypertension as modifiable and nonmodifiable risk factors and the underlying cellular mechanisms that may underlie heterogeneous stroke outcomes. Most of the preclinical investigative studies of poststroke NVU dysfunction are carried out primarily in male stroke models lacking underlying co-morbid conditions, which is very different from the human condition. As such, the evolution of translational medicine to target the NVU for improved stroke outcomes remains elusive; however, it is attainable with further research.

The effects of resveratrol and exercise on age and gender-dependent alterations of vascular functions and biomarkers

The purpose of this study was to determine the effects of resveratrol and regular aerobic exercise on vascular functions and biomarkers related to vessel responsiveness in an age and gender-dependent manner. The study used young (3 months) and old (12 months) male and female Wistar albino rats. Resveratrol was given in the drinking water (0.05 mg/ml; approximately 7.5 mg/kg) for 6 weeks. In the exercise group, all rats performed treadmill running at 20 m/min on a 0° incline, 40 min/day, 3 times a week, for 6 weeks. Acetylcholine-induced, endothelium-dependent and sodium nitroprusside-mediated, endothelium-independent relaxations of rat thoracic aorta and blood levels of biomarkers were separately changed by resveratrol intake and exercise-training in an age and gender-dependent manner. Antioxidant enzymes and eNOS expressions in vessels were elevated by resveratrol and exercise. Resveratrol and exercise enhanced gene expressions of non-selective PDE1, 2, 3 and cAMP selective PDE4 but not cGMP selective PDE5 in the aorta. In addition, the aortic mRNA expression of inflammation markers were altered by resveratrol and exercise-training. The results of the study demonstrated that vessel responsiveness and biomarkers related to vascular functions were altered by resveratrol consumption and exercise-training in an age and gender-dependent manner.

Effect of the Antioxidant Lipoic Acid in Aortic Phenotype in a Marfan Syndrome Mouse Model

Marfan syndrome (MFS) cardiovascular manifestations such as aortic aneurysms and cardiomyopathy carry substantial morbidity/mortality. We investigated the effects of lipoic acid, an antioxidant, on ROS production and aortic remodeling in a MFS mgΔ^loxPneo mouse model. MFS and WT (wild-type) 1-month-old mice were allocated to 3 groups: untreated, treated with losartan, and treated with lipoic acid. At 6 months old, echocardiography, ROS production, and morphological analysis of aortas were performed. Aortic ROS generation in 6-month-old MFS animals was higher at advanced stages of disease in MFS. An unprecedented finding in MFS mice analyzed by OCT was the occurrence of focal inhomogeneous regions in the aortic arch, either collagen-rich extremely thickened or collagen-poor hypotrophic regions. MFS animals treated with lipoic acid showed markedly reduced ROS production and lower ERK1/2 phosphorylation; meanwhile, aortic dilation and elastic fiber breakdown were unaltered. Of note, lipoic acid treatment associated with the absence of focal inhomogeneous regions in MFS animals. Losartan reduced aortic dilation and elastic fiber breakdown despite no change in ROS generation. In conclusion, oxidant generation by itself seems neutral with respect to aneurysm progression in MFS; however, lipoic acid-mediated reduction of inhomogeneous regions may potentially associate with less anisotropy and reduced chance of dissection/rupture.

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.

Prostacyclin does not affect sweating but induces skin vasodilatation to a greater extent in older versus younger women: roles of NO and KCa channels

NEW FINDINGS

What is the central question of this study? It remains unknown whether ageing modulates prostacyclin-induced cutaneous vasodilatation in women. What is the main finding and its importance? Prostacyclin induced cutaneous vasodilatation, albeit the magnitude of increase at lower concentrations of prostacyclin was greater in older relative to young women. This response was associated with greater contributions of nitric oxide synthase and calcium-activated potassium channels. Our results suggest that administration of prostacyclin might be an effective therapy to reverse microvascular hypoperfusion, especially in older women. We previously reported that prostacyclin induces cutaneous vasodilatation but not sweating in younger and older men. Furthermore, we demonstrated that nitric oxide synthase and calcium-activated potassium (K_Ca ) channels contribute to the prostacyclin-induced cutaneous vasodilatation in younger men, although these contributions are diminished in older men. Given that the effects of ageing might differ between men and women, the above results cannot simply be applied to women. In this study, cutaneous vascular conductance and sweat rate were evaluated in younger (mean ± SD, 22 ± 3 years old) and older (55 ± 7 years old) women (10 per group) at four intradermal forearm skin sites treated as follows: (i) lactated Ringer solution without any drug (control); (ii) 10 mm N^G -nitro-l-arginine (l-NNA), a non-specific nitric oxide synthase inhibitor; (iii) 50 mm tetraethylammonium (TEA), a non-specific K_Ca channel blocker; or (iv) 10 mm l-NNA plus 50 mm TEA. All four sites were co-administered with prostacyclin in an incremental manner (0.04, 0.4, 4, 40 and 400 μm, each for 25 min). Surprisingly, increases in cutaneous vascular conductance in response to 0.04-4 μm prostacyclin were greater in older relative to younger women (all P ≤ 0.05), and these age-related differences were diminished when both l-NNA and TEA were administered simultaneously (all P > 0.05). No effect on sweat rate was observed in either group (all concentrations, P > 0.05). We show that although prostacyclin does not mediate sweating, it induces cutaneous vasodilatation, and this response elicited by lower concentrations of prostacyclin is greater in older relative to younger women. This greater cutaneous vasodilatation in older women is likely to be attributable to nitric oxide synthase- and K_Ca channel-dependent mechanisms.