17beta-estradiol prevents oxidative stress and decreases blood pressure in ovariectomized rats

Estrone-mediated lowering of ROS and NOX4 improves endothelial function in ovariectomized wistar rats

Estrone (E1) constitutes the primary component in oral conjugated equine estrogens (CEEs) and serves as the principal estrogen precursor in the female circulation in the post-menopause. E1 induces endothelium-dependent vasodilation and activate PI3K/NO/cGMP signaling. To assess whether E1 mitigates vascular dysfunction associated with postmenopause and explore the underlying mechanisms, we examined the vascular effects of E1 in ovariectomized (OVX) rats, a postmenopausal experimental model. Blood pressure was measured using tail-cuff plethysmography, and aortic rings were isolated to assess responses to phenylephrine, acetylcholine (ACh), and sodium nitroprusside. Responses to ACh in rings pre-incubated with superoxide dismutase (SOD), catalase (CAT), or apocynin were also evaluated. Protein expression of SOD, CAT, NOX1, NOX2, and NOX4 was determined by Western blotting. E1 treatment resulted in decreased body weight and retroperitoneal fat, increased uterine weight, and prevented elevated blood pressure in the OVX group. Furthermore, E1 improved endothelium-dependent ACh vasodilation, activated compensatory antioxidant mechanisms - i.e. increased SOD and CAT antioxidant enzymes activity, and decreased NOX4 expression. This, in turn, helped prevent oxidative stress and endothelial dysfunction in OVX rats. Additionally, E1 treatment reversed the increased total LDL cholesterol observed in the OVX group. The findings underscore protective effects of E1 on the cardiovascular system, counteracting OVX-related oxidative stress and endothelial dysfunction in Wistar rats. E1 exhibits promising therapeutic benefits for managing cardiovascular health, particularly in postmenopausal conditions.

Maternal exposure to glyphosate-based herbicide causes vascular dysfunction in offspring female rats

This study analyzed how glyphosate exposure in the gestational period affects vascular function in their female offspring and whether oxidative stress is involved in this effect. To this, pregnant Wistar rats were exposed through drinking water to 0.2% of a glyphosate commercial formulation, and we analyzed the response to acetylcholine and phenylephrine in the aorta from offspring of Glyphosate-based herbicide (O-GBH) and controls (O-CON) rats at six months of age. Relaxation to acetylcholine was reduced in O-GBH than in O-CON. Acute Indomethacin and Apocynin increased relaxation to acetylcholine in O-GBH. The aorta from O-GBH was hyperactive to phenylephrine; the preincubation with N-nitro-L-arginine methyl ester (L-NAME) increased contraction to phenylephrine more in O-CON than O-GBH. TEMPOL similarly reduced phenylephrine response, and L-NAME prevented this effect. The TBARS and GSH levels were increased in O-GBH than in O-CON. Results reinforce the concept that oxidative stress during the perinatal period contributes to the development of vascular changes in adulthood. Results also reveal that oxidative stress parameters altered, and the current levels considered safe for exposure to Glyphosate deserve further investigation, especially in the female gender.

Anti-Menopausal Effect of Soybean Germ Extract and Lactobacillus gasseri in the Ovariectomized Rat Model

Menopause is a significant phase in a woman's life. Menopausal symptoms can affect overall well-being and quality of life. Conventionally, hormone replacement therapy (HRT) is used to alleviate menopausal symptoms; however, depending on the conditions, HRT may lead to side effects, necessitating the exploration of alternative therapies with fewer side effects. In this study, we investigated the effects of a combination of soybean germ extract (S30) containing 30% (w/w) isoflavone and a probiotic, Lactobacillus gasseri (LGA1), on menopausal conditions in an ovariectomized (OVX) rat model. We evaluated the impact of S30+LGA on body weight, estrogen markers, uterine and bone health, vascular markers, and neurotransmitter levels. The results revealed that treatment with S30+LGA1 significantly improved body weight and uterine and bone health. Moreover, S30+LGA1 demonstrated promising effects on lipid profile, liver function, and vascular markers and positively impacted serotonin and norepinephrine levels, indicating potential mood-enhancing effects. In conclusion, S30+LGA1, possessing anti-menopausal effects in vitro and in vivo, can be recommended as a soy-based diet, which offers various health benefits, especially for menopausal women.

Sex hormone dose escalation for treating abnormal sleep in ovariectomized rats: in vitro GABA synthesis in sleep-related brain areas

No data in the literature have evaluated sex hormone dose escalation for treating abnormal sleep of ovariectomized rats-nor studies on the role of sex hormones in GABA synthesis of rats' sleep-related areas. The main aim of this study was to determine the maximum tolerated dose (MTD) of estradiol (ET), progesterone (PT), and the mixture of both (EPT) to restore normal sleep in a model of menopause in rats. The second purpose was to describe the in vitro activity of glutamate decarboxylase (GAD) in sleep-related brain areas in the presence or absence of sex hormones. A weekly dose-escalation design of ET, PT, or EPT was implemented in ovariectomized rats (six per group). Dose escalation continued until the dose at which 100% of the rats exhibited a state of "complete somnolence." Doses that were not toxic or did not show side effects were considered. For in vitro experiments, sleep-related brain areas were separated and incubated with radiolabeled glutamate. Estradiol (17β-E2), progesterone (P), and pyridoxal phosphate (PLP) were added to this assay, and GAD activity was determined. Under the same conditions, a second test was carried out, but the P antagonist RU486 was added to assess the role of P in GAD activity. Ovariectomy increased periodic awakenings compared to those determined for the SHAM group. The EPT for ovariectomized rats was very effective by the fifth week in decreasing arousal and achieving a similar sleep behavior to the SHAM-control group. Rats tolerated the ET, PT, and EPT well to the maximum planned dose (0.66 mg/kg and 4.4 mg/kg, respectively). No lethal events occurred; the MTD was reached. The in vitro studies indicated that the presence of 17β-E2 plus P in the assay triggered the activity of isotype 65 GAD in all the studied brain areas. RU486 in the incubation medium blocked such activity; however, the action of isotype 67 GAD was not blocked by RU486. A dose-escalation model was determined; the MTD coincided with the maximum dose of ET and PT used. However, the EPT combination restored normal sleep in the menopause model compared to the SHAMs without toxic effects. The in vitro model demonstrated that 17β-E2 plus P presence in the assay increased the activity of GAD65 in the studied brain tissues.

Gender-based research underscores sex differences in biological processes, clinical disorders and pharmacological interventions

Earlier research has presumed that the male and female biology is similar in most organs except the reproductive system, leading to major misconceptions in research interpretations and clinical implications, with serious disorders being overlooked or misdiagnosed. Careful research has now identified sex differences in the cardiovascular, renal, endocrine, gastrointestinal, immune, nervous, and musculoskeletal systems. Also, several cardiovascular, immunological, and neurological disorders have shown differences in prevalence and severity between males and females. Genetic variations in the sex chromosomes have been implicated in several disorders at young age and before puberty. The levels of the gonadal hormones estrogen, progesterone and testosterone and their receptors play a role in the sex differences between adult males and premenopausal women. Hormonal deficiencies and cell senescence have been implicated in differences between postmenopausal and premenopausal women. Specifically, cardiovascular disorders are more common in adult men vs premenopausal women, but the trend is reversed with age with the incidence being greater in postmenopausal women than age-matched men. Gender-specific disorders in females such as polycystic ovary syndrome, hypertension-in-pregnancy and gestational diabetes have attained further research recognition. Other gender-related research areas include menopausal hormone therapy, the "Estrogen Paradox" in pulmonary arterial hypertension being more predominant but less severe in young females, and how testosterone may cause deleterious effects in the kidney while having vasodilator effects in the coronary circulation. This has prompted the National Institutes of Health (NIH) initiative to consider sex as a biological variable in research. The NIH and other funding agencies have provided resources to establish state-of-the-art centers for women health and sex differences in biology and disease in several academic institutions. Scientific societies and journals have taken similar steps to organize specialized conferences and publish special issues on gender-based research. These combined efforts should promote research to enhance our understanding of the sex differences in biological systems beyond just the reproductive system, and provide better guidance and pharmacological tools for the management of various clinical disorders in a gender-specific manner.

Fisetin attenuates doxorubicin-induced cardiotoxicity by inhibiting the insulin-like growth factor II receptor apoptotic pathway through estrogen receptor-α/-β activation

Doxorubicin (DOX), an effective chemotherapeutic drug, has been used to treat various cancers; however, its cardiotoxic side effects restrict its therapeutic efficacy. Fisetin, a flavonoid phytoestrogen derived from a range of fruits and vegetables, has been reported to exert cardioprotective effects against DOX-induced cardiotoxicity; however, the underlying mechanisms remain unclear. This study investigated fisetin's cardioprotective role and mechanism against DOX-induced cardiotoxicity in H9c2 cardiomyoblasts and ovariectomized (OVX) rat models. MTT assay revealed that fisetin treatment noticeably rescued DOX-induced cell death in a dose-dependent manner. Moreover, western blotting and TUNEL-DAPI staining showed that fisetin significantly attenuated DOX-induced cardiotoxicity in vitro and in vivo by inhibiting the insulin-like growth factor II receptor (IGF-IIR) apoptotic pathway through estrogen receptor (ER)-α/-β activation. The echocardiography, biochemical assay, and H&E staining results demonstrated that fisetin reduced DOX-induced cardiotoxicity by alleviating cardiac dysfunction, myocardial injury, oxidative stress, and histopathological damage. These findings imply that fisetin has a significant therapeutic potential against DOX-induced cardiotoxicity.

Sex differences in preclinical models of hypertension

Hypertension remains the primary contributor in the development of cardiovascular disease which is rapidly increasing worldwide. High blood pressure affects men and women differently and understanding these sex differences is the ultimate unmet need for researchers in this field. Due to the inherent differences in hypertension prevalence, control and outcomes between men and women, novel research needs to be carried out to tackle these disparities and improve targeted treatment. Animal models of hypertension have provided valuable insights into the sexual dimorphism of blood pressure mechanisms. The availability of genetic and non-genetic hypertensive strains allows the opportunity to study diverse environmental and genetic factors that affect blood pressure, therefore presenting a valuable tool for researchers. Sex differences are present before birth and throughout life, which presents a challenge for the study of disease development in humans, but these complexities can be resolved with the use of in vivo models that display similarities to human disease. The aim of the present review is to provide an overview of the different available animal models of hypertension that present sexual dimorphisms and to discuss their relevance to humans.

Long-term Ovariectomy Reduces Tolerance of Rats to Myocardial Ischemia-reperfusion Injury

Background

The harmful impact of ovariectomy on myocardial ischemia-reperfusion (M/IR) injury has been established in the short term.

Objectives

In this study, we aimed to investigate the long-term effects of ovariectomy on M/IR injury.

Methods

Two methods involving dorsolateral skin incisions were used to induce the ovariectomized (OVX) rat model. The rats were divided into 2 groups: Control and OVX (n = 6). At the end of the study, the hearts were isolated and subjected to global ischemia using the Langendorff apparatus. Cardiac function indices (CFIs) were recorded, including left ventricular end-diastolic pressure (LVEDP), peak rates of positive (+dp/dt) and negative (-dp/dt) changes in LV pressure, and LV-developed pressure (LVDP). At the end of the reperfusion period, the hearts were used to measure the size of the infarct, levels of nitric oxide metabolites (NOx), and mRNA expression of NO synthase (NOS) enzymes, including endothelial (eNOS), neuronal (nNOS), and inducible (iNOS).

Results

Compared to controls, OVX rats had larger infarct size by 51%, higher LVEDP by 29%, and lower recovery of +dp/dt, -dp/dt, and LVDP by 29%, 22%, and 35%, respectively. Furthermore, in heart tissue, rats that underwent OVX had significantly higher concentrations of nitrate, nitrite, and NOx by 79%, 82%, and 83%, respectively. Additionally, these rats had lower mRNA levels of eNOS by 38% and higher mRNA levels of iNOS by 71%.

Conclusions

The long-term deficiency of estrogen increased the expression of iNOS and decreased the expression of eNOS in the heart tissue of OVX rats. Imbalanced NOS expressions were associated with exacerbated responses to M/IR injury in OVX rats.

Protective effects of long-term nitrate administration against ovariectomy-induced kidney dysfunction in rats

BACKGROUND

Menopause is associated with higher risks of chronic kidney disease. We determined the effect of nitrate on ovariectomy-induced kidney dysfunction METHODS: Control, ovariectomized (OVX), control + nitrate, and OVX + nitrate female Wistar rats (n = 10/group); sodium nitrate (100 mg/L) administered in drinking water for 9 months. Glomerular filtration rate (GFR) and albumin excretion rate (AER) were calculated from serum and urine parameters. At month 9, serum and kidney levels of nitric oxide (NO) metabolites (NOx), oxidative stress indices, and mRNA expression of endothelial NO synthase (eNOS) were measured; with histological analyses of the kidney.

RESULTS

Compared to controls, OVX rats had lower GFR (31%, p = 0.0079), higher glomerular tuft volume (30%, p = 0.0402), and Bowman's capsule space (39%, p = 0.0224). OVX rats had lower serum NOx (33%, p = 0.0061) and kidney eNOS mRNA expression (34%, p = 0.0368). Nitrate administration to: (i) control rats increased serum NOx (59%, p < 0.0001), with no effect on other parameters; (ii) OVX rats increased serum (85%, p < 0.0001) and kidney (106%, p = 0.0008) NOx values, and restored kidney eNOS expression to normal value. Nitrate administration to OVX rats increased GFR (36%, p = 0.0361) and restored glomerular tuft volume and Bowman's capsule space to normal values. In OVX rats, it also increased serum catalase (CAT) activity, serum and kidney total antioxidant capacity (TAC), and decreased serum malondialdehyde (MDA).

CONCLUSIONS

Low-dose long-term nitrate administration protects against ovariectomy-induced kidney dysfunction in rats. This effect is associated with reducing ovariectomy-induced oxidative stress and restoring eNOS-derived NO deficiency in systemic circulation and the kidney.

Effects of a low-sodium diet in patients with idiopathic hyperaldosteronism: a randomized controlled trial

Background

Idiopathic hyperaldosteronism (IHA) is one of the most common types of primary aldosteronism (PA), an important cause of hypertension. Although high dietary sodium is a major risk factor for hypertension, there is no consensus on the recommended dietary sodium intake for IHA.

Objective

This study investigated the effect of a low-sodium diet on hemodynamic variables and relevant disease biomarkers in IHA patients, with the aim of providing a useful reference for clinical treatment.

Methods

Fifty IHA patients were evenly randomized into two groups and provided, after a 7-day run-in period (100 mmol/d sodium), either a low-sodium diet (50 mmol/d sodium) or a normal sodium diet (100 mmol/d sodium) for an additional 7 days. After the 14-day intervention (conducted without potassium supplementation), changes in blood pressure (BP) and serum potassium were evaluated in both groups.

Results

After the dietary intervention, the low sodium group exhibited, compared to the normal sodium group, decreased BP (SBP: 121.8 ± 12.8 vs. 129.9 ± 12.1 mmHg, p < 0.05; DBP: 82.6 ± 7.6 vs. 86.4 ± 8.2 mmHg, p < 0.05; MAP: 95.7 ± 8.8 vs. 100.9 ± 8.4 mmHg, p < 0.05) and increased serum potassium levels (3.38 ± 0.33 vs. 3.07 ± 0.27 mmol/L, p < 0.001). The low sodium group showed also better control of both BP and serum potassium: BP <140/90 mmHg in 70.0% of total patients (76.0% vs. 64.0%, in the low and normal sodium groups, respectively; p > 0.05), BP <130/85 mmHg in 38.0% of total patients (56.0% vs. 20.0%, p < 0.05), BP <120/80 mmHg in 28.0% of total patients (44.0% vs. 12.0%, p < 0.05); serum potassium ≥3.5 mmol/L in 22.0% of total patients (32.0% vs. 12.0% in the low and normal sodium groups, respectively; p = 0.088). There were differences between the controlled BP group (<120/80 mmHg) and the non-controlled BP group (≥120/80 mmHg) in gender, BP at baseline, and type of diet (low vs. normal sodium). Female gender and low-sodium diet were protective factors for BP control.

Conclusions

A low-sodium diet is effective in lowering BP and elevating serum potassium in IHA patients. Female patients on a low-sodium diet are more likely to achieve BP control (<120/80 mmHg). We advocate a dietary sodium intake of 50 mmol/d for IHA patients.

Clinical trial registration

https://clinicaltrials.gov, Identifier NCT05649631.

Maternal obesity and the impact of associated early-life inflammation on long-term health of offspring

The prevalence of obesity is increasingly common in the United States, with ~25% of women of reproductive age being overweight or obese. Metaflammation, a chronic low grade inflammatory state caused by altered metabolism, is often present in pregnancies complicated by obesity. As a result, the fetuses of mothers who are obese are exposed to an in-utero environment that has altered nutrients and cytokines. Notably, both human and preclinical studies have shown that children born to mothers with obesity have higher risks of developing chronic illnesses affecting various organ systems. In this review, the authors sought to present the role of cytokines and inflammation during healthy pregnancy and determine how maternal obesity changes the inflammatory landscape of the mother, leading to fetal reprogramming. Next, the negative long-term impact on offspring’s health in numerous disease contexts, including offspring’s risk of developing neuropsychiatric disorders (autism, attention deficit and hyperactive disorder), metabolic diseases (obesity, type 2 diabetes), atopy, and malignancies will be discussed along with the potential of altered immune/inflammatory status in offspring as a contributor of these diseases. Finally, the authors will list critical knowledge gaps in the field of developmental programming of health and diseases in the context of offspring of mothers with obesity, particularly the understudied role of hematopoietic stem and progenitor cells.

Estrogen normalizes maternal HFD-induced vascular dysfunction in offspring by regulating ATR

Previous studies have shown that female offspring are resistant to fetal high-fat diet (HFD)-induced programming of heightened vascular contraction; however, the underlying mechanisms remain unclear. The present study tested the hypothesis that estrogen plays a key role in protecting females from fetal programming of increased vascular contraction induced by maternal HFD exposure. Pregnant rats were fed a normal diet (ND) or HFD (60% kcal from fat). Ovariectomy (OVX) and 17β-estradiol (E₂) replacement were performed on 8-week-old female offspring. Aortas were isolated from adult female offspring. Maternal HFD exposure increased angiotensin II (Ang II)-induced contractions of the aorta in adult OVX offspring, which was abrogated by E₂ replacement. The AT₁ receptor (AT₁R) antagonist losartan (10 μM), but not the AT₂ receptor (AT₂R) antagonist PD123319 (10 μM), completely blocked Ang II-induced contractions in both ND and HFD offspring. In addition, HFD exposure caused a decrease in endothelium-dependent relaxations induced by acetylcholine (ACh) in adult OVX but not OVX-E₂ offspring. However, it had no effect on sodium nitroprusside (SNP)-induced endothelium-independent aorta relaxation in any of the six groups. Maternal HFD feeding increased AT₁R, but not AT₂R, leading to an increased AT₁R/AT₂R ratio in HFD-exposed OVX offspring, associated with selective decreases in DNA methylation at the AT_1aR promoter, which was ameliorated by E₂ replacement. Our results indicated that estrogen play a key role in sex differences of maternal HFD-induced vascular dysfunction and development of hypertensive phenotype in adulthood by differently regulating vascular AT₁R and AT₂R gene expression through a DNA methylation mechanism.

Immuno-regenerative biomaterials for in situ cardiovascular tissue engineering - Do patient characteristics warrant precision engineering?

In situ tissue engineering using bioresorbable material implants - or scaffolds - that harness the patient's immune response while guiding neotissue formation at the site of implantation is emerging as a novel therapy to regenerate human tissues. For the cardiovascular system, the use of such implants, like blood vessels and heart valves, is gradually entering the stage of clinical translation. This opens up the question if and to what extent patient characteristics influence tissue outcomes, necessitating the precision engineering of scaffolds to guide patient-specific neo-tissue formation. Because of the current scarcity of human in vivo data, herein we review and evaluate in vitro and preclinical investigations to predict the potential role of patient-specific parameters like sex, age, ethnicity, hemodynamics, and a multifactorial disease profile, with special emphasis on their contribution to the inflammation-driven processes of in situ tissue engineering. We conclude that patient-specific conditions have a strong impact on key aspects of in situ cardiovascular tissue engineering, including inflammation, hemodynamic conditions, scaffold resorption, and tissue remodeling capacity, suggesting that a tailored approach may be required to engineer immuno-regenerative biomaterials for safe and predictive clinical applicability.

Long Term Sodium Nitrate Administration Positively Impacts Metabolic and Obesity Indices in Ovariectomized Rats

BACKGROUND

In postmenopausal women, nitric oxide (NO) deficiency is associated with obesity and type 2 diabetes (T2D). This study aims at determining the long-term effects of low-dose nitrate administration on metabolic and obesity indices in ovariectomized (OVX) rats.

METHODS

OVX rat model was induced using the two dorsolateral skin incision method. Two months after ovariectomy, rats were divided into three groups (n = 10/group): Control, OVX, and OVX+nitrate, and the latter received sodium nitrate at a dose of 100 mg/L in their drinking water for nine months. Fasting serum glucose and lipid profile were measured every month. A glucose tolerance test was performed at months 1, 3, and 9 (the end of the study). Obesity indices were calculated, and histological analyses were performed on the gonadal adipose tissues at month 9.

RESULTS

OVX rats had impaired fasting glucose, glucose intolerance, and dyslipidemia with higher obesity indices at month 9. Nitrate improved glucose and lipid metabolism in OVX rats and decreased body weight (6.9%), body mass index (12.5%), Lee index (5.4%), adiposity index (23.9%), abdominal circumference (10.5%), and thoracic circumference (17.1%). Also, nitrate decreased adipocyte area by 49% and increased adipocyte density by 193% in gonadal adipose tissue.

CONCLUSION

Long-term low-dose nitrate administration improves glucose and lipid metabolism in OVX rats in association with decreasing OVX-induced adiposity, increasing adipocyte density, and decreasing adipocyte area. These findings provide support for a potential therapeutic role of nitrate in postmenopausal women with some features of metabolic syndrome.

Identification of the Active Ingredient and Beneficial Effects of Vitex rotundifolia Fruits on Menopausal Symptoms in Ovariectomized Rats

Estrogen replacement therapy is a treatment to relieve the symptoms of menopause. Many studies suggest that natural bioactive ingredients from plants resemble estrogen in structure and biological functions and can relieve symptoms of menopause. The fruit of V. rotundifolia, called "Man HyungJa" in Korean, is a traditional medicine used to treat headache, migraine, eye pain, neuralgia, and premenstrual syndrome in Korea and China. The aim of the present study was to confirm that V. rotundifolia fruit extract (VFE) exerts biological functions similar to those of estrogen in menopausal syndrome. We investigated its in vitro effects on MCF-7 cells and in vivo estrogen-like effects on weight gain and uterine contraction in ovariectomized rats. Using the polar extract, the active constituents of VFE (artemetin, vitexicarpin, hesperidin, luteolin, vitexin, and vanillic acid) with estrogen-like activity were identified in MCF-7 cells. In animal experiments, the efficacy of VFE in ameliorating body weight gain was similar to that of estrogen, as evidenced from improvements in uterine atrophy. Vitexin and vitexicarpin are suggested as the active constituents of V. rotundifolia fruits.

SRC-3 Deficiency Exacerbates Neurological Deficits in a Mouse Model of Intracerebral Hemorrhage: Role of Oxidative Stress

Intracerebral hemorrhage (ICH) causes long term neurological abnormality or death. Oxidative stress is closely involved in ICH mediated brain damage. Steroid receptor cofactor 3 (SRC-3), a p160 family member, is widely expressed in the brain and regulates transactivation of Nrf2, a key component of antioxidant response. Our study aims to test if SRC-3 is implicated in ICH mediated brain injury. We first examined levels of SRC-3 and oxidative stress in the brain of mice following ICH and analyzed their correlation. Then ICH was induced in wild type (WT) and SRC-3 knock out mice and how SRC-3 deletion affected ICH induced brain damage, oxidative stress and behavioral outcome was assessed. We found that SRC-3 mRNA and protein expression levels were reduced gradually after ICH induction in WT mice along with an increase in oxidative stress levels. Correlation analysis revealed that SRC-3 mRNA levels negatively correlated with oxidative stress. Deletion of SRC-3 further increased ICH induced brain edema, neurological deficit score and oxidative stress and exacerbated ICH induced behavioral abnormality including motor dysfunction and cognitive impairment. Our findings suggest that SRC-3 is involved in ICH induced brain injury, probably through modulation of oxidative stress.

Rhaponticin contained Rheum officinale root extract improved Postmenopause symptom of Ovariectomized Rat

Postmenopausal women have decreased levels of the hormone estrogen. Reduced estrogen levels will often involve many symptoms that reduced quality of life. This research aims to analyze the effects of Rheum officinale root extract on postmenopausal model rats. To this end, thirty rats underwent ovariectomy (OVX) surgery and six rats were operated without having their ovaries removed. The OVX was confirmed by body weight–uterus weight ratio and a vaginal swab. Six groups of the rats were performed: SHAM group and negative control groups are given vehicle; the positive control was assigned tamoxifen; and the extract has been given three doses 7, 35, and 175 mg/200 g BW, respectively, for 30 days. The calcium content of bone ash was measured using atomic absorption spectrophotometer. Blood pressure was evaluated using CODA^®, and the metabolites in the blood were assessed using gas chromatography–mass spectrometry (MS) and high-performance liquid chromatography. As a result, using ultra-performance liquid chromatography (UPLC)-MS, we found that the extract's major component was rhaponticin and its metabolites. The bone calcium levels increased with increasing doses of the extract. In the OVX group, the bone calcium content was decreased significantly 51.56% ± 8.9% g compared with the SHAM group 62.97% ±5.6% g, and the administration of Rheum extract could restore the calcium content of the bone to become 69.27% ± 3.8% g. From the above data, we concluded that Rheum root extracts contain astrigin, rhaponticin, rhapontigenin, and desoxyrhaponticin. Rheum root extract could improve calcium content and lipid profiles of OVX rats by stimulation osteoblastogenesis. Rheum root extracts could control the blood pressure of OVX rats by reducing lipid profiles.

Cardioprotective effects of severe calorie restriction from birth in adult ovariectomized rats

AIMS

Menopause is a female condition induced by a reduction of ovarian hormone and is related to an increase in cardiovascular diseases in women. We have shown that severe calorie restriction (SCR) from birth reduces the cardiometabolic risk in adult male Wistar rats. In this study, we investigated the effects of SCR from birth to adulthood on cardiovascular function of ovariectomized rats.

MAIN METHODS

From birth to adulthood, rats were daily fed ad libitum (control group - C) or with 50% of the amount consumed by the control group (calorie-restricted group - R). At 90 days, half of the rats in each group underwent bilateral ovariectomy (OVX), totaling 4 groups: C-Sham, C-OVX, R-Sham, R-OVX. Systolic blood pressure (SBP), heart rate (HR) and, double product (DP) index were recorded by tail-cuff plethysmography. Cardiac function was analyzed by the Langendorff technique and cardiomyocyte diameter was accessed by histologic analysis. Additionally, cardiac SERCA2 content and redox status were evaluated.

KEY FINDINGS

C-OVX rats exhibited reduced cardiac function and cardiac non-enzymatic total antioxidant capacity (TAC). R-Sham animals showed reduced SBP, DP, HR, improved cardiac function, reduced cardiac protein carbonyl derivatives and increased TAC, catalase, and superoxide dismutase activities. R-OVX rats maintained reduced SBP, DP, HR, and increased contractility and relaxation indexes. R-Sham and R-OVX rats exhibited preserved heart mass and reduced cardiomyocyte diameter. Cardiac SERCA2 content did not differ between the groups.

SIGNIFICANCE

Taken together, our findings show cardioprotective effects of SCR from birth in adult ovariectomized rats.

Vascular dysfunction as a potential culprit of sarcopenia

Aging-related changes to biological structures such as cardiovascular and musculoskeletal systems contribute to the development of comorbid conditions including cardiovascular disease and frailty, and ultimately lead to premature death. Although, frail older adults often demonstrate both cardiovascular and musculoskeletal comorbidities, the etiology of sarcopenia, and especially the contribution of cardiovascular aging is unclear. Aging-related vascular calcification is prevalent in older adults and is a known risk factor for cardiovascular disease and death. The effect vascular calcification has on function during aging is not well understood. Emerging findings suggest vascular calcification can impact skeletal muscle perfusion, negatively affecting nutrient and oxygen delivery to skeletal muscle, ultimately accelerating muscle loss and functional decline. The present review summarizes existing evidence on the biological mechanisms linking vascular calcification with sarcopenia during aging.

A mechanical acupuncture instrument mitigates the endoplasmic reticulum stress and oxidative stress of ovariectomized rats

Background

Acupuncture has become a common complementary and alternative treatment approach for anxiety and depression. However, there is little research on the detailed mechanism of acupuncture therapy relieving depression. Previously, 17β-estradiol (E2) was shown to prevent oxidative stress and endoplasmic reticulum (ER) stress in ovariectomized (OVX) rats. This study investigated whether stimulation of Sanyinjiao (SP6) using a mechanical acupuncture instrument can alleviate depression-like behavior caused by estrogen deficiency in OVX rats. Furthermore, we found that acupuncture reduced ER stress and oxidative stress-related proteins expression.

Methods

The OVX operation was performed on female SD rats that were separated into four groups: The E2 (2.5 μg/kg, i.p.) injection group (OVX + E2), the OVX group (OVX), and the OVX with acupuncture stimulation group (OVX + SP6). Non-acupoint stimulation group (OVX + NonAcu). The acupuncture point stimulation began three weeks after surgery. The depressive behavior was analyzed by the forced swim test and open field test. The 8-OHDG, BiP, Sigma receptor 1, pJNK, PDI, Ero1-Iα and Calnexin protein levels were evaluated by immunoreactivity in the amygdala.

Results

Acupuncture stimulation reduced depressive behavior and altered depression-related proteins. Stimulation of SP6 decreased the immobility time of the FST and altered the ER stress and oxidative stress marker proteins, such as 8-OHDG, BiP, pJNK, PDI, Ero1-Ia and Calnexin.

Conclusion

Our results indicated that acupuncture at SP6 showed a significant antidepressant-like effect on an OVX-induced depression rat model by mitigation of ER stress and oxidative stress in amygdala.

Reproductive Regulation and Oxidative Stress Alleviation of Chinese Herbal Medicine Therapy in Ovariectomised Mouse Model

In Taiwan, the herbal formula B401 is considered as a health supplement for middle-aged women that can alleviate sweating, anxiety, and sleep disorders. However, the relevant mechanisms are still unclear. In this study, we evaluated the beneficial effects of the herbal formula B401 therapy in the reproductive regulation of ovariectomised mice. Female ICR mice were randomised into four groups: wild-type (WT) mice with sham treatment, wild-type mice treated with the herbal formula B401, bilateral ovariectomised (OVX) mice with sham treatment, and bilateral ovariectomised mice treated with the herbal formula B401. Mice were orally given the herbal formula B401 at a dose of 30 mg/kg bw/day for 2 weeks. At the end of oral treatment with sham or the herbal formula B401, levels of reactive oxygen species (ROS), calcium, phosphorus, and estradiol-17β in the blood; uterine weight and endometrial thickness; and expressions of estrogen receptor α (ERα), estrogen receptor β (ERβ), progesterone receptor (PR), vascular endothelial growth factor (VEGF), and superoxide dismutase 2 (SOD2) in the uterine tissue were examined and then compared among the four groups of mice. We found that OVX mice decreased levels of calcium, phosphorus, and estradiol-17β in the blood, decreased uterine weight and endometrial thickness, and decreased expressions of ERα, ERβ, PR, and SOD2 in the uterine tissue but increased blood ROS levels compared with those of WT mice. In addition, OVX mice with the herbal formula B401 therapy can increase levels of calcium, phosphorus, and estradiol-17β in the blood, increase uterine weight and endometrial thickness, and increase expressions of ERα, ERβ, PR, VEGF, and SOD2 in the uterine tissue but decrease blood ROS levels. Our results may provide reasonable explanation for the reproductive regulation of the herbal formula B401 therapy.

Exercise training initiated at old stage of lifespan attenuates aging-and ovariectomy-induced cardiac and renal oxidative stress: Role of baroreflex

BACKGROUND

The association of aging and menopause is a potent risk factor for cardiometabolic disease. We studied the impact of aerobic exercise training (ET) initiated in the old stage of lifespan in hemodynamics, metabolic, autonomic and oxidative stress.

METHODS

Aged (18 months old) female Wistar rats were divided into: ovariectomized and untrained (AG-OVX), and ovariectomized and trained (AG-OVXt, ET for 8 weeks). Intact aged (AG) and young female rats (3 months old; Y) were also studied. Blood pressure and metabolic parameters were measured. Baroreflex sensitivity (BRS) was studied by bradycardic (BR) and tachycardic (TR) responses to vasoactive drugs. Cardiac and renal lipid peroxidation (LPO), catalase (CAT), superoxide dismutase (SOD) and gluthatione peroxidase (GPx), and gluthatione redox balance (GSH/GSSG) were analyzed.

RESULTS

AG-OVXt group increased aerobic performance in 35%, decreased adipose tissue and triglycerides in 36% and 27%, respectively, and improved insulin tolerance in 50% in comparison to AG-OVX. AG-OVX presented hypertensive levels of blood pressure (systolic: 155 ± 5, diastolic: 111 ± 3 mmHg). In contrast, AG-OVXt presented blood pressure values similar to Y rats (systolic: 129 ± 3, diastolic: 112 ± 3 mmHg). TR and BR were reduced by 70% and 46%, respectively, in AG-OVX vs. Y. Once more, AG-OVXt presented similar results to Y. ET decreased LPO in the heart and kidney. In the latter, renal CAT and SOD were corrected by ET, while cardiac redox balance was partially recovered. Improved BRS was correlated with improved oxidative stress markers.

CONCLUSIONS

Even when initiated after aging and ovariectomy deleterious effects, ET is able to normalize BRS and highly improve cardiac and renal oxidative stress.

Gender Differences in Hypertension

Hypertension is the leading risk factor for global mortality and morbidity and remains the major preventable cause of cardiovascular diseases. Gender differences in risk factors and awareness, treatment, and control of hypertension have been well established in humans. There are significant differences in epidemiology and clinical characteristic of hypertension between men and women. Moreover, gender differences are linked with several specific types of hypertension, including postmenopausal hypertension, white coat hypertension, masked hypertension, and hypertensive disorders of pregnancy. Gender differences have been implicated in the prevalence and determinants of hypertension and prehypertension whereas the control rate is similar between men and women taking antihypertensive medication. Importantly, distinct roles of the angiotensin-converting enzyme 2/Apelin signaling, sex hormone, endothelin-1, and sympathetic nervous activity contribute to sex differences in blood pressure control. This review summarizes gender differences in clinical features and determinants of hypertension and the underlying mechanisms responsible for hypertension.

The potential role of testosterone in hypertension and target organ damage in hypertensive postmenopausal women

Objective: The aim of this study was to confirm the potential role of testosterone in hypertension and target organ damage (TOD) in hypertensive postmenopausal women.

Methods: A matched group study was conducted. One hundred sixty-one hypertensive postmenopausal women between 45 and 65 years of age were enrolled as group 1. Another 161 age-matched hypertensive men were enrolled as group 2. Ambulatory blood pressure monitoring, echocardiographic imaging, vascular function, sex hormones and clinical characteristics were evaluated. Quantitative data were analyzed using independent Student’s t-test and multiple regression analysis.

Results: The mean and load level of blood pressure were lower in women than in men (P<0.05), except for the mean level and load of the nocturnal systolic blood pressure (SBP) (123.77±15.72 mmHg vs 126.35±15.64 mmHg, and 50.43±30.31% vs 55.35±28.51%, P>0.05). However, the carotid-femoral pulse wave velocity (cf-PWV) in women was higher than that in men (9.68±2.23 m/s vs 8.03±2.82 m/s, P<0.05). The ratio of the early diastolic mitral peak flow velocity to early diastolic mitral annular velocity (E/Em) was obviously impaired (13.06±3.53 vs 12.05±3.68, P<0.05) in women. Furthermore, in women, a positive correlation was found between testosterone and cf-PWV (γ=0.157, P=0.046), and Cf-PWV was positively related to the mean level of nighttime SBP (γ=0.210, P=0.008). Moreover, nocturnal SBP was a risk factor for E/Em (γ=0.156, P=0.048, P<0.05).

Conclusion: Testosterone may play a role in the correlation between hypertension and TOD in hypertensive postmenopausal women.

Clinical Trial number: This research study was registered under the ClinicalTrials.gov PRS Website (NCT03451747).

Oral contraceptives augment the exercise pressor reflex during isometric handgrip exercise

We sought to determine whether oral contraception alters the gender-related differences observed in the exercise pressor reflex during isometric handgrip exercise. Fifteen men, fifteen normally menstruating women (WomenNM), and fifteen women taking monophasic oral contraceptives (WomenOC) completed two trials of a 3-min isometric handgrip exercise protocol performed at 30% of their maximal voluntary contraction: (1) where arterial occlusion was applied to the previously exercising arm during a 3-min recovery period (Occlusion trial); (2) where no arterial occlusion was applied during recovery (Control trial). Handgrip exercise elicited greater increases in mean arterial pressure (MAP) in MEN compared to both female groups (P < 0.05), and in WomenOC compared to WomenNM in both trials (P = 0.01, P = 0.03). After 3 min of recovery, sBP was 12% (P = 0.01) and 9% (P = 0.02) higher in the Occlusion trial when compared to the Control trial for MEN and WomenOC. Conversely, arterial occlusion in recovery from handgrip did not sustain elevated sBP in the Occlusion trial, and sBP returned to recovery levels not different to the Control trial, in WomenNM (P = 0.41). These data indicate that gender-related differences in the metaboreflex during isometric handgrip exercise exist between men and normally menstruating women, but are blunted when men are compared to women taking oral contraceptives. We conclude that the suppression of 17β-estradiol and/or progestogen in women via the administration of oral contraceptives attenuates sex-related differences in the metaboreflex during isometric handgrip exercise.

Contributions of sex to cerebrovascular function and pathology

Sex differences exist in how cerebral blood vessels function under both physiological and pathological conditions, contributing to observed sex differences in risk and outcomes of cerebrovascular diseases (CBVDs), such as vascular contributions to cognitive impairment and dementia (VCID) and stroke. Throughout most of the lifespan, women are protected from CBVDs; however, risk increases following menopause, suggesting sex hormones may play a significant role in this protection. The cerebrovasculature is a target for sex hormones, including estrogens, progestins, and androgens, where they can influence numerous vascular functions and pathologies. While there is a plethora of information on estrogen, the effects of progestins and androgens on the cerebrovasculature are less well-defined. Estrogen decreases cerebral tone and increases cerebral blood flow, while androgens increase tone. Both estrogens and androgens enhance angiogenesis/cerebrovascular remodeling. While both estrogens and androgens attenuate cerebrovascular inflammation, pro-inflammatory effects of androgens under physiological conditions have also been demonstrated. Sex hormones exert additional neuroprotective effects by attenuating oxidative stress and maintaining integrity and function of the blood brain barrier. Most animal studies utilize young, healthy, gonadectomized animals, which do not mimic the clinical conditions of aging individuals likely to get CBVDs. This is also concerning, as sex hormones appear to mediate cerebrovascular function differently based on age and disease state (e.g. metabolic syndrome). Through this review, we hope to inspire others to consider sex as a key biological variable in cerebrovascular research, as greater understanding of sex differences in cerebrovascular function will assist in developing personalized approaches to prevent and treat CBVDs.

Effects of Urtica dioica hydro-alcoholic extract on blood serum glucose and lipid profiles of female Wistar rats with long-term estrogen deficiency

In this study, the effects of Urtica dioica hydro-alcoholic extract were investigated on the blood glucose and lipid profiles of female ovariectomized and non-ovariectomized rats. In total, 32 adult female rats were divided into four groups (eight each) including control and ovariectomy groups as well as non-ovariectomy and ovariectomy groups treated with 200 mg kg^-1 of Urtica dioica extract orally in the last five weeks of the study starting from the week 56^th. The duration of the study was 60 weeks. Glucose, serum lipid profiles and pancreatic pathological alterations were determined in these groups at the end of experiment. Serum glucose, triglyceride (TG), very-low-density lipoprotein (VLDL), and TG/high-density lipoprotein (HDL) ratio indicated a significant increase in the healthy female rats under treatment with Urtica dioica extract compared to others. The TG, cholesterol, HDL, low-density lipoprotein (LDL) and VLDL showed a significant increase in menopaused rats compared to others. The interaction of consuming Urtica dioica extract and ovariectomy caused significant decreases in glucose, TG, VLDL, HDL/LDL ratio and TG/HDL ratio. Consumption of Urtica dioica extract by non-menopaused rats damaged the beta cells in Langerhans islets. Results of the present study revealed that the consumption of Urtica dioica extract is not beneficial and has diabetogenic effects in female non-ovariectomized rats compared to ovariectomized ones.

Impact of flaxseed and soy nuts as dietary supplements on lipid profile, insulin sensitivity, and GLUT4 expression in ovariectomized rats

We assessed the effects of a diet with flaxseed or soy nuts versus estradiol on the lipid profile, insulin sensitivity, and glucose transporter type 4 (GLUT4) expression in ovariectomized female rats. Forty-four female Wistar rats (90 days old) underwent ovariectomy and were divided into 4 groups: C (standard diet), E (standard diet + subcutaneous 17β-estradiol pellets), L (standard diet + flaxseed + subcutaneous placebo pellets), and S (standard diet + soy nuts + subcutaneous placebo pellets). Customized diets and the insertion of pellets were started 21 days after ovariectomy and were continued for another 21 days. We measured body mass, insulin tolerance, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, and GLUT4 (in cardiac and adipose tissues). We found a lower body mass and a lower Lee index in group E and a trend toward improved insulin sensitivity in group S (p = 0.066). Groups L and S showed a better lipid profile when compared with group C. Microsomal GLUT4 increased in group L (in cardiac and adipose tissues), and plasma membrane GLUT4 increased in groups E, L, and S (in both tissues). We conclude that flaxseed and soy nuts as dietary supplements improve lipid profile and increase GLUT4 expression.

The effects of estradiol and testosterone on renal tissues oxidative after central injection of angiotensin II in female doca - salt treated rats

Background Although numerous studies have proven that estrogen (Est) has a protective effect on the development of hypertension, more research needs to be done to show its detailed mechanism in a variety of hypertension. The important role of active oxygen species in blood pressure is well defined. We examined whether or not sex hormones change the growth of reactive oxygen species (ROS) ‎in kidneys after central microinjection of angiotensin II (Ang II).‎ Materials and methods Female Wistar rats, 8 weeks old (200 ± 10 g) were used in this study. The animal groups were (1) Sham, (2) Ovariectomy (OVX), (3) Sham-Hypertension (Sham-Hyper), (4) OVX-Hypertension (OVX-Hyper), (5) Sham-Hyper-Est, (6) OVX-Hyper-Est‎;‎ (7) Sham-Hyper-Testosterone (Tst) and (8) OVX-Hyper-Tst. Solutions of 1% NaCl and 0.1 KCl ‎were used and desoxycorticostrone (doca-salt) was injected (45 mg/kg) 3 times a week in Hypertension groups. Estradiol and Tst (2 mg/kg and ‎5 mg/kg‎; daily; subcutaneously) for 4 weeks. Ang II (50 μM, 5 μL) was microinjected by intracerebroventricular ( i.c.v.) infusion and malondialdehyde (MDA) and thiol in the kidneys were measured. Results MDA in the kidneys was increased by Ang II and doca-salt treatments. Both estradiol and Tst decreased the kidney's MDA. The level of thiol was higher in Hyper ‎groups and reversed after treatment with estradiol and Tst. Conclusions Our findings suggest that central effect of Ang II on blood pressure and kidney ‎disease is accompanied with increased levels of oxidative stress in the kidneys. Indeed sex hormones change the ROS level in the kidneys after central ‎microinjection of Ang II.‎‎.

Increased sleep time and reduced energy expenditure contribute to obesity after ovariectomy and a high fat diet

In this study we examined if sleep time, caloric intake and energy expenditure are important contributors to development of ovariectomy-induced obesity in mice fed control or high fat diet (HFD). Twelve female mice at 6 weeks of age were divided into 2 groups: Sham (n = 5) and ovariectomized (OVX, n = 7). Mice were fed control diet for 9 weeks and shifted to HFD for additional 9 weeks. Food intake and body weight were measured daily and body composition was measured weekly by EchoMRI. Energy expenditure (EE), oxygen consumption (VO2), motor activity (MA) and sleep time were monitored at week 9 during control diet and HFD. OVX did not alter caloric intake, body weight or body composition, MA, sleep time or fasting blood glucose, but slightly reduced EE compared to Sham mice on control diet. After HFD feeding, OXV mice had similar caloric intake, lean mass, MA, and blood glucose levels but had significantly greater weight gain (8.2 ± 1.0 vs. 4.8 ± 1.2 g, p < 0.05), increased fat mass and sleep time, and reduced EE (3.3 ± 0.4 vs. 5.5 ± 0.2 kcal/h) and VO2 (1.12 ± 0.01 vs. 1.83 ± 0.05 ml/min) compared to Sham group. Daytime blood pressure was higher while nighttime heart rate was lower in OVX group. These results suggest that OVX may not substantially alter body weight or body composition in mice fed a normal diet, but when combined with HFD it increases sleep time and reduces EE, leading to greater weight gain and adiposity without altering food intake.

Combined aerobic and resistance exercise training attenuates cardiac dysfunctions in a model of diabetes and menopause

The study aimed at evaluating the effects of combined aerobic and resistance exercise training on cardiac morphometry and function, oxidative stress and inflammatory parameters in diabetic ovariectomized rats. For this, female Wistar rats (10 weeks-old) were divided into 4 groups (n = 8): euglycemic (E), diabetic (streptozotocin, 50 mg/kg, iv) (D), diabetic ovariectomized (DO) and trained diabetic ovariectomized (TDO). The combined exercise training was performed on a treadmill and in a ladder adapted to rats (8 weeks, at 40-60% of maximal capacity). The left ventricle (LV) morphometry and function were evaluated by echocardiography. Oxidative stress and inflammatory markers were measured on ventricles tissue. The sedentary diabetic animals (D and DO) showed impaired systolic and diastolic functions, as well as increased cardiac overload, evaluated by myocardial performance index (MPI- D: 0.32 ± 0.05; DO: 0.39 ± 0.13 vs. E: 0.25 ± 0.07), in relation to E group. Systolic and MPI dysfunctions were exacerbated in DO when compared to D group. The DO group presented higher protein oxidation and TNF-α/IL-10 ratio than D groups. Glutathione redox ratio (GSH/GSSG) and IL-10 were decreased in both D and DO groups when compared to E group. Exercise training improved exercise capacity, systolic and diastolic functions and MPI (0.18±0.11). The TDO group showed reduced protein oxidation and TNF-α/IL-10 ratio and increased GSH/GSSG and IL-10 in relation to the DO group. These results showed that combined exercise training was able to attenuate the cardiac dysfunctions, probably by reducing inflammation and oxidative stress in an experimental model of diabetes and menopause.

Estrogen Therapy Worsens Cardiac Function and Remodeling and Reverses the Effects of Exercise Training After Myocardial Infarction in Ovariectomized Female Rats

There is an increase in the incidence of cardiovascular events such as myocardial infarction (MI) after menopause. However, the use of estrogen therapy (E2) remains controversial. The aim of this study was to evaluate the effects of E2, alone and combined with exercise training (ET), on cardiac function and remodeling in ovariectomized (OVX) rats after MI. Wistar female rats underwent ovariectomy, followed by MI induction were separated into five groups: S; MI; MI+ET; MI+E2; and MI+ET+E2. Fifteen days after MI or sham surgery, treadmill ET and/or estrogen therapy [17-β estradiol-3-benzoate (E2), s.c. three times/week] were initiated and maintained for 8 weeks. After the treatment and/or training period, the animals underwent cardiac hemodynamic evaluation through catheterization of the left ventricle (LV); the LV systolic and diastolic pressures (LVSP and LVEDP, respectively), maximum LV contraction and relaxation derivatives (dP/dt+ and dP/dt−), and isovolumic relaxation time (Tau) were assessed. Moreover, histological analyses of the heart (collagen and hypertrophy), cardiac oxidative stress [advanced oxidation protein products (AOPPs)], pro- and antioxidant protein expression by Western blotting and antioxidant enzyme activity in the heart were evaluated. The MI reduced the LVSP, dP/dt+ and dP/dt− but increased the LVEDP and Tau. E2 did not prevent the MI-induced changes in cardiac function, even when combined with ET. An increase in the dP/dt+ was observed in the E2 group compared with the MI group. There were no changes in collagen deposition and myocyte hypertrophy caused by the treatments. The increases in AOPP, gp91-phox, and angiotensin II type 1 receptor expression induced by MI were not reduced by E2. There were no changes in the expression of catalase caused by MI or by the treatments, although, a reduction in superoxide dismutase (SOD) expression occurred in the groups subjected to E2 treatment. Whereas there were post-MI reductions in activities of SOD and catalase enzymes, only that of SOD was prevented by ET. Therefore, we conclude that E2 therapy does not prevent the MI-induced changes in cardiac function and worsens parameters related to cardiac remodeling. Moreover, E2 reverses the positive effects of ET when used in combination, in OVX infarcted female rats.

Effects of Inducible Nitric Oxide Synthase Inhibition on Cardiovascular Risk of Adult Endotoxemic Female Rats: Role of Estrogen

Aim: Autonomic modulation responds to ovarian hormones and estrogen increases nitric oxide bioavailability. Also, females have minor susceptibility to sepsis and a higher survival rate. However, few studies have evaluated the role of estrogen in cardiovascular, autonomic, and oxidative parameters during initial endotoxemia and under inducible nitric oxide synthase (iNOS) inhibition in female rats.

Methods: Female wistar rats were subjected to ovariectomy and divided into three groups: OVX (ovariectomized), OVX+E (OVX plus daily estradiol) and SHAM (false surgery). After 8 weeks, mean arterial pressure (MAP) and heart rate (HR) were recorded in non-anesthetized catheterized rats, before and after intravenous LPS injection, preceded by S-methylisothiourea sulfate (SMT) injection, or sterile saline. Cardiovascular recordings underwent spectral analysis for evaluation of autonomic modulation. Two hours after LPS, plasma was collected to assess total radical-trapping antioxidant (TRAP), nitrite levels (NO2), lipoperoxidation (LOOH), and paraoxonase 1 (PON1) activity.

Results: Two hours after LPS, females treated with SMT presented a decrease of MAP, when compared to saline-LPS groups. At this same time, all SMT+LPS groups presented an increase of sympathetic and a decrease of parasympathetic modulation of HR. Two hours after saline+LPS, OVX presented decreased total radical-trapping antioxidant (TRAP) compared to SHAM. When treated with SMT+LPS, OVX did not altered TRAP, while estradiol reduced LOOH levels.

Conclusion: iNOS would be responsible for sympathetic inhibition and consumption of antioxidant reserves of females during endotoxemia, since iNOS is inhibited, treatment with estradiol could be protective in inflammatory challenges.

Estrogen and DPP4 inhibitor, but not metformin, exert cardioprotection via attenuating cardiac mitochondrial dysfunction in obese insulin-resistant and estrogen-deprived female rats

OBJECTIVE

Cardiac function was markedly compromised in obese insulin-resistant and estrogen-deprived rats. Metformin and dipeptidyl peptidase-4 inhibitor (vildagliptin) were reported to improve cardiac function in insulin-resistant rats. Their effects on the heart under estrogen-deprived conditions are, however, unknown. Therefore, the effects of metformin, vildagliptin, and estrogen on the cardiac function in estrogen-deprived insulin-resistant female rats were investigated.

METHODS

Bilateral ovariectomized female rats (n = 48) were divided to be fed with either a normal diet (ND) or a high-fat diet (HFD) for 12 weeks. Then, both ND- and HFD-fed groups were subdivided to receive a vehicle, estrogen (50 μg/kg), metformin (30 mg/kg), or vildagliptin (3 mg/kg) for 4 weeks (n = 6/group). Heart rate variability, echocardiography, metabolic and biochemical parameters, cardiac function, and mitochondrial function were determined. Sham-operated female rats (n = 6) were used as a control.

RESULTS

Both ND- and HFD-fed ovariectomized rats developed insulin resistance, depressed heart rate variability, and decreased cardiac contractility. Although treatment with metformin, vildagliptin, and estrogen improved metabolic status and cardiac function, only estrogen and vildagliptin improved diastolic blood pressure and left ventricular ±dP/dt, and also reduced mitochondrial impairment, apoptosis, and oxidative stress in HD-fed ovariectomized rats.

CONCLUSIONS

Treatment with estrogen and vildagliptin provided more beneficial effects in the inhibition of oxidative stress, apoptosis, and cardiac mitochondrial dysfunction, and preserved cardiac contractile performance in estrogen-deprived insulin-resistant female rats.

Sex-specific differences in hypertension and associated cardiovascular disease

Although intrinsic mechanisms that regulate arterial blood pressure (BP) are similar in men and women, marked variations exist at the molecular, cellular and tissue levels. These physiological disparities between the sexes likely contribute to differences in disease onset, susceptibility, prevalence and treatment responses. Key systems that are important in the development of hypertension and cardiovascular disease (CVD), including the sympathetic nervous system, the renin-angiotensin-aldosterone system and the immune system, are differentially activated in males and females. Biological age also contributes to sexual dimorphism, as premenopausal women experience a higher degree of cardioprotection than men of similar age. Furthermore, sex hormones such as oestrogen and testosterone as well as sex chromosome complement likely contribute to sex differences in BP and CVD. At the cellular level, differences in cell senescence pathways may contribute to increased longevity in women and may also limit organ damage caused by hypertension. In addition, many lifestyle and environmental factors - such as smoking, alcohol consumption and diet - may influence BP and CVD in a sex-specific manner. Evidence suggests that cardioprotection in women is lost under conditions of obesity and type 2 diabetes mellitus. Treatment strategies for hypertension and CVD that are tailored according to sex could lead to improved outcomes for affected patients.

Sex differences in abdominal aortic aneurysms

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

Sex differences in maternal gestational hypertension-induced sensitization of angiotensin II hypertension in rat offspring: the protective effect of estrogen

Recent studies demonstrate that maternal hypertension during pregnancy sensitizes an angiotensin (ANG) II-induced increase in blood pressure (BP) in adult male offspring that was associated with upregulation of mRNA expression of several renin-angiotensin-aldosterone system (RAAS) components and NADPH oxidase in the lamina terminalis (LT) and paraventricular nucleus (PVN). The purpose of the present study was to test whether there are sex differences in the maternal hypertension-induced sensitization of ANG II hypertension, and whether sex hormones are involved in the sensitization process. Male offspring of hypertensive dams showed an enhanced hypertensive response to systemic ANG II when compared with male offspring of normotensive dams and to female offspring of either normotensive or hypertensive dams. Castration did not alter the hypertensive response to ANG II in male offspring. Intact female offspring had no upregulation of RAAS components and NADPH oxidase in the LT and PVN, whereas ovariectomy (OVX) upregulated mRNA expression of several RAAS components and NADPH oxidase in these nuclei and induced a greater increase in the pressor response to ANG II in female offspring of hypertensive dams compared with female offspring of normotensive dams. This enhanced increase in BP was partially attenuated by 17β-estradiol replacement in the OVX offspring of hypertensive dams. The results suggest that maternal hypertension induces a sex-specific sensitization of ANG II-induced hypertension and mRNA expression of brain RAAS and NADPH oxidase in offspring. Female offspring are protected from maternal hypertension-induced sensitization of ANG II hypertension, and female sex hormones are partially responsible for this protective effect.

Hyperglycaemia in pregnant rats causes sex-related vascular dysfunction in adult offspring: role of cyclooxygenase-2

NEW FINDINGS

What is the central question of this study? Hyperglycaemia during pregnancy induces vascular dysfunction and hypertension in male offspring. Given that female offspring from other fetal programming models are protected from the effects of fetal insult, the present study investigated whether there are sex differences in blood pressure and vascular function in hyperglycaemia-programmed offspring. What is the main finding and its importance? We demonstrated that hyperglycaemia in pregnant rats induced vascular dysfunction and hypertension only in male offspring. We found sex differences in oxidative stress and cyclooxygenase-2-derived prostanoid production that might underlie the vascular dysfunction. These differences, particularly in resistance arteries, may in part explain the absence of hypertension in female offspring born to hyperglycaemic dams. Exposure to maternal hyperglycaemia induces hypertension and vascular dysfunction in adult male offspring. Given that female offspring from several fetal programming models are protected from the effects of fetal insult, in this study we analysed possible differences relative to sex in blood pressure and vascular function in hyperglycaemia-programmed offspring. Hyperglycaemia was induced on day 7 of gestation (streptozotocin, 50 mg kg^-1 ). Blood pressure, acetylcholine and phenylephrine or noradrenaline responses were analysed in the aorta and mesenteric resistance arteries of 3-, 6- and 12-month-old male and female offspring. Thromboxane A₂ release was analysed with commercial kits and superoxide anion (O₂^- ) production by dihydroethidium-emitted fluorescence. Male but not female offspring of hyperglycaemic dams (O-DR) had higher blood pressure than control animals (O-CR). Contraction in response to phenylephrine increased and relaxation in response to acetylcholine decreased only in the aorta from 12-month-old male O-DR and not in age-matched O-CR. Contractile and vasodilator responses were preserved in both the aorta and mesenteric resistance arteries from female O-DR of all ages. Pre-incubation with tempol, superoxide dismutase, indomethacin, NS-398, furegrelate or SQ29548 decreased contraction in response to phenylephrine and potentiated relaxation in response to acetylcholine in 12-month-old male O-DR aorta. In this artery, thromboxane A₂ release and O₂^- generation were greater in O-DR than O-CR groups. In conclusion, exposure to hyperglycaemia in utero results in sex-specific and age-dependent hypertension. The fact that vascular function is preserved in female O-DR may in part explain the absence of hypertension in this group. In contrast, the peripheral artery dysfunction associated with increased cyclooxygenase-2-derived production of vasoconstrictor prostanoids could underlie the increased blood pressure in male O-DR.

Oxidative injuries induced by maternal low-protein diet in female brainstem

Many studies have shown that a maternal low-protein diet increases the susceptibility of offspring to cardiovascular disease in later-life. Moreover, a lower incidence of cardiovascular disease in females than in males is understood to be largely due to the protective effect of high levels of estrogens throughout a woman's reproductive life. However, to our knowledge, the role of estradiol in moderating the later-life susceptibility of offspring of nutrient-deprived mothers to cardiovascular disease is not fully understood. The present study is aimed at investigating whether oxidative stress in the brainstem caused by a maternal low-protein diet administered during a critical period of fetal/neonatal brain development (i.e during gestation and lactation) is affected by estradiol levels. Female Wistar rat offspring were divided into four groups according to their mothers' diets and to the serum estradiol levels of the offspring at the time of testing: (1) 22 days of age/control diet: (2) 22 days of age/low-protein diet; (3) 122 days of age/control diet: (4) 122 days of age/low-protein diet. Undernutrition in the context of low serum estradiol compared to undernutrition in a higher estradiol context resulted in increased levels of oxidative stress biomarkers and a reduction in enzymatic and non-enzymatic antioxidant defenses. Total global oxy-score showed oxidative damage in 22-day-old rats whose mothers had received a low-protein diet. In the 122-day-old group, we observed a decrease in oxidative stress biomarkers, increased enzymatic antioxidant activity, and a positive oxy-score when compared to control. We conclude from these results that following a protein deficiency in the maternal diet during early development of the offspring, estrogens present at high levels at reproductive age may confer resistance to the oxidative damage in the brainstem that is very apparent in pre-pubertal rats.

Maternal low-protein diet in female rat heart: possible protective effect of estradiol

Several studies have shown that maternal low-protein (LP) diet induces detrimental effects in cardiovascular system and oxidative stress in male animals. Additional studies suggested that female has lower incidence of cardiovascular disease. However until present data, the possible effects of estradiol on the undernutrition during gestational and lactation periods are not discussed. The present study was conducted to evaluate the effects of a maternal LP diet during gestational and lactation period on oxidative balance in the female rat hearts ventricles at two ages. Dams were fed with normal protein (NP) or a LP diet during the gestational and lactation period, and their female offspring were divided into age groups (22 or 122 days, corresponding to a low or high estrogen level) composing four experimental groups. Evaluating the nutritional effect showed an increase in oxidative stress biomarkers and decrease in enzymatic defense in LP-22D compared with NP-22D. In contrast, no changes were observed in malondialdehyde and carbonyls, but an increase in glutathione-S-transferase (GST) activity in the LP-122D compared with NP-122D. The global oxy-score in the LP-22D group indicated a predominance of oxidative damage when compared with NP-22D, while in LP-122D group the global oxy-score was restored to NP-122D levels. Evaluating the estradiol effect, our data show a significant decrease in oxidative stress with increase in CAT and GST activity, associated with increase in intracellular thiols. Our data suggest that in situation with low levels of estradiol, hypoproteic diet during gestation and lactation period has detrimental effects on heart, however when estradiol levels raise, the detrimental effects induced are mitigated.

Swimming training prevents coronary endothelial dysfunction in ovariectomized spontaneously hypertensive rats

Estrogen deficiency and hypertension are considered major risk factors for the development of coronary heart disease. On the other hand, exercise training is considered an effective form to prevent and treat cardiovascular diseases. However, the effects of swimming training (SW) on coronary vascular reactivity in female ovariectomized hypertensive rats are not known. We aimed to evaluate the effects of SW on endothelium-dependent coronary vasodilation in ovariectomized hypertensive rats. Three-month old spontaneously hypertensive rats (SHR, n=50) were divided into four groups: sham (SH), sham plus swimming training (SSW), ovariectomized (OVX), and ovariectomized plus swimming training (OSW). The SW protocol (5 times/week, 60 min/day) was conducted for 8 weeks. The vasodilatory response was measured in isolated hearts in the absence and presence of a nitric oxide synthase inhibitor (L-NAME, 100 µM). Cardiac oxidative stress was evaluated in situ by dihydroethidium fluorescence, while the expression of antioxidant enzymes (SOD-2 and catalase) and their activities were assessed by western blotting and spectrophotometry, respectively. Vasodilation in SHR was significantly reduced by OVX, even in the presence of L-NAME, in conjunction with an increased oxidative stress. These effects were prevented by SW, and were associated with a decrease in oxidative stress. Superoxide dismutase 2 (SOD-2) and catalase expression increased only in the OSW group. However, no significant difference was found in the activity of these enzymes. In conclusion, SW prevented the endothelial dysfunction in the coronary bed of ovariectomized SHR associated with an increase in the expression of antioxidant enzymes, and therefore may prevent coronary heart disease in hypertensive postmenopausal women.

Hormonal therapy with estradiol and drospirenone improves endothelium-dependent vasodilation in the coronary bed of ovariectomized spontaneously hypertensive rats

Drospirenone (DRSP) is a progestin with anti-aldosterone properties and it reduces blood pressure in hypertensive women. However, the effects of DRSP on endothelium-dependent coronary vasodilation have not been evaluated. This study investigated the effects of combined therapy with estrogen (E2) and DRSP on endothelium-dependent vasodilation of the coronary bed of ovariectomized (OVX) spontaneously hypertensive rats. Female spontaneously hypertensive rats (n=87) at 12 weeks of age were randomly divided into sham operated (Sham), OVX, OVX treated with E2 (E2), and OVX treated with E2 and DRSP (E2+DRSP) groups. Hemodynamic parameters were directly evaluated by catheter insertion into the femoral artery. Endothelium-dependent vasodilation in response to bradykinin in the coronary arterial bed was assessed using isolated hearts according to a modified Langendorff method. Coronary protein expression of endothelial nitric oxide synthase and estrogen receptor alpha (ER-α) was assessed by Western blotting. Histological slices of coronary arteries were stained with hematoxylin and eosin, and morphometric parameters were analyzed. Oxidative stress was assessed in situ by dihydroethidium fluorescence. Ovariectomy increased systolic blood pressure, which was only prevented by E2+DRSP treatment. Estrogen deficiency caused endothelial dysfunction, which was prevented by both treatments. However, the vasodilator response in the E2+DRSP group was significantly higher at the three highest concentrations compared with the OVX group. Reduced ER-α expression in OVX rats was restored by both treatments. Morphometric parameters and oxidative stress were augmented by OVX and reduced by E2 and E2+DRSP treatments. Hormonal therapy with E2 and DRSP may be an important therapeutic option in the prevention of coronary heart disease in hypertensive post-menopausal women.

Ovarian Hormone Deprivation Reduces Oxytocin Expression in Paraventricular Nucleus Preautonomic Neurons and Correlates with Baroreflex Impairment in Rats

The prevalence of cardiovascular diseases including hypertension increases dramatically in women after menopause, however the mechanisms involved remain incompletely understood. Oxytocinergic (OTergic) neurons are largely present within the paraventricular nucleus of the hypothalamus (PVN). Several studies have shown that OTergic drive from PVN to brainstem increases baroreflex sensitivity and improves autonomic control of the circulation. Since preautonomic PVN neurons express different types of estrogen receptors, we hypothesize that ovarian hormone deprivation causes baroreflex impairment, autonomic imbalance and hypertension by negatively impacting OTergic drive and oxytocin levels in pre-autonomic neurons. Here, we assessed oxytocin gene and protein expression (qPCR and immunohistochemistry) within PVN subnuclei in sham-operated and ovariectomized Wistar rats. Conscious hemodynamic recordings were used to assess resting blood pressure and heart rate and the autonomic modulation of heart and vessels was estimated by power spectral analysis. We observed that the ovarian hormone deprivation in ovariectomized rats decreased baroreflex sensitivity, increased sympathetic and reduced vagal outflows to the heart and augmented the resting blood pressure. Of note, ovariectomized rats had reduced PVN oxytocin mRNA and protein expression in all pre-autonomic PVN subnuclei. Furthermore, reduced PVN oxytocin protein levels were positively correlated with decreased baroreflex sensitivity and negatively correlated with increased LF/HF ratio. These findings suggest that reduced oxytocin expression in OTergic neurons of the PVN contributes to the baroreflex dysfunction and autonomic dysregulation observed with ovarian hormone deprivation.

Effect of Cross-Sex Hormonal Replacement on Antioxidant Enzymes in Rat Retroperitoneal Fat Adipocytes

We report the effect of cross-sex hormonal replacement on antioxidant enzymes from rat retroperitoneal fat adipocytes. Eight rats of each gender were assigned to each of the following groups: control groups were intact female or male (F and M, resp.). Experimental groups were ovariectomized F (OvxF), castrated M (CasM), OvxF plus testosterone (OvxF + T), and CasM plus estradiol (CasM + E₂) groups. After sacrifice, retroperitoneal fat was dissected and processed for histology. Adipocytes were isolated and the following enzymatic activities were determined: Cu-Zn superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and glutathione reductase (GR). Also, glutathione (GSH) and lipid peroxidation (LPO) were measured. In OvxF, retroperitoneal fat increased and adipocytes were enlarged, while in CasM rats a decrease in retroperitoneal fat and small adipocytes are observed. The cross-sex hormonal replacement in F rats was associated with larger adipocytes and a further decreased activity of Cu-Zn SOD, CAT, GPx, GST, GR, and GSH, in addition to an increase in LPO. CasM + E₂ exhibited the opposite effects showing further activation antioxidant enzymes and decreases in LPO. In conclusion, E₂ deficiency favors an increase in retroperitoneal fat and large adipocytes. Cross-sex hormonal replacement in F rats aggravates the condition by inhibiting antioxidant enzymes.

Resistance or aerobic training decreases blood pressure and improves cardiovascular autonomic control and oxidative stress in hypertensive menopausal rats

We investigated whether resistance training (RT) vs. aerobic training (AT) differentially impacts on arterial pressure and related mechanisms in ovariectomized spontaneously hypertensive rats (SHRs). Female SHRs were ovariectomized and assigned to one of the following groups: sedentary, AT, or RT; sham sedentary SHR were used as control group. AT was performed on a treadmill, whereas RT was performed on a vertical ladder. Both exercise protocols were performed for 8 wk, 5 days/wk. Arterial pressure, baroreflex sensitivity, autonomic modulation, and cardiac oxidative stress parameters (lipid peroxidation, protein oxidation, redox balance, NADPH oxidase, and antioxidant enzymes activities) were analyzed. Ovariectomy increased mean arterial pressure (∼9 mmHg), sympathetic modulation (∼40%), and oxidative stress in sedentary rats. Both RT and AT reduced mean arterial pressure (∼20 and ∼8 mmHg, respectively) and improved baroreflex sensitivity compared with sedentary ovariectomized rats. However, RT-induced arterial pressure decrease was significantly less pronounced than AT. Lipid peroxidation and protein oxidation were decreased while antioxidant enzymes were increased in both trained groups vs. sedentaries. The reduced gluthatione was higher after AT vs. other groups, whereas oxidized gluthatione was lower after RT vs. AT. Moreover, sympathetic and parasympathetic modulations were highly correlated with cardiac oxidative stress parameters. In conclusion, both RT and AT can decrease arterial pressure in a model of hypertension and menopause; although, at different magnitudes this decrease was related to attenuated autonomic dysfunction in association with cardiac oxidative stress improvement in both exercise protocols.

Interaction of central Angiotensin II and estrogen on systolic blood pressure in female DOCA-salt treated rats

Background:

There is a probable interaction of central angiotensin II (Ang II) and estrogen (Est) on blood pressure in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Therefore, in the present study, the interaction between Ang II and Est in ovariectomized (Ovx) and Sham rats that were treated with DOCA- salt was evaluated.

Materials and Methods:

The female rats were divided into 10 groups as follows: Sham, Ovx, Sham-DOCA, Ovx-DOCA, Sham-DOCA-estrogen (E), Ovx DOCA-E, Sham-DOCA-losartan (L), Ovx-DOCA-L, Sham–DOCA-L-E, and Ovx-DOCA-L-E. The Est groups received estradiol valerate (2 mg/kg; daily; subcutaneously (s.c)) for four weeks. Following that, several doses of Ang II (0.5, 5, 50, 500, 5000 ng/5 μl) were injected via the intracerebroventricular (i.c.v) route and the changes in systolic blood pressure (SBP) were evaluated. In the losartan groups, 200 μg losartan was injected (i.c.v) 15 minutes after the Ang II injection and the blood pressure was recorded. Treatment by DOCA was performed by removal of one kidney, injection of DOCA (45 mg/kg i.p), and adding of sodium chloride (NaCl) (1%) and potassium chloride (KCl) (0.1%) in the drinking water.

Results:

The SBP was increased by Ang II and this effect in DOCA-salt treated rat was higher than in the untreated groups. The effect of Ang II on SBP in groups that were treated with Est and L was lower than that in the DOCA-salt groups. Increase in SBP was strongly attenuated by Ang II in groups that were co-treated with both Est and L compared to the DOCA-treated rats. These results showed that Est significantly attenuated the effect of central Ang II on SBP in the DOCA-salt treated rats.

Conclusion:

We suggest that there are interactions between E and Ang II in the control of blood pressure in DOCA-salt treated rats.