Influence of sex on cardiovascular drug responses: role of estrogen

Estrogen Dampens Central Cannabinoid Receptor 1-mediated Neuroexcitation and Pressor Response in Conscious Female Rats

Activation of the rostral ventrolateral medulla (RVLM) cannabinoid receptor-1 (CB₁R) causes nNOS-dependent increases in sympathetic activity, blood pressure (BP) and heart rate (HR) in male rats. However, it remains unknown if the CB₁R-mediated neurochemical and cardiovascular responses are influenced by the ovarian sex hormones, particularly estrogen (E₂). Therefore, we studied the effects of intra-RVLM CB₁R activation (WIN 55,212-2) on BP and HR in conscious female rats under the following hormonal states: (1) highest E₂ level (proestrus sham-operated, SO); (2) E₂-deprivation (ovariectomized, OVX); (3) OVX with E₂ replacement (OVXE2). Intra-RVLM WIN55,212-2 elicited dose (100-400 pmol) dependent pressor and tachycardic responses, in OVX rats, which replicated the reported responses in male rats. However, in SO and OVXE2 rats, the CB₁R-mediated pressor response was attenuated and the tachycardic response reverted to bradycardic response. The neurochemical findings suggested a key role for the upregulated RVLM sympathoexcitatory molecules phosphorated protein kinase B, phosphorated neuronal nitric oxide synthase and reactive oxygen species in the exaggerated CB₁R-mediated BP and HR responses in OVX rats, and an E₂-dependent dampening of these responses. The intra-RVLM WIN55212-2-evoked cardiovascular and neurochemical responses were CB₁R-mediated because they were attenuated by prior CB₁R blockade (AM251). Our findings suggest that attenuation of RVLM neuroexcitation and oxidative stress underlies the protection conferred by E₂, in female rats, against the CB₁R-mediated adverse cardiovascular effects.

Sex differences in opioid receptor mediated effects: Role of androgens

An abundance of data indicates there are sex differences in endogenous opioid peptides and opioid receptors, leading to functional differences in sensitivity to opioid receptor mediated behaviors between males and females. Many of these sex differences are mediated by the effects of gonadal hormones on the endogenous opioid system. Whereas much research has examined the role of ovarian hormones on opioid receptor mediated endpoints, comparatively less research has examined the role of androgens. This review describes what is currently known regarding the influence of androgens on opioid receptor mediated endpoints and how androgens may contribute to sex differences in these effects. The review also addresses the clinical implications of androgenic modulation of opioid receptor mediated behaviors and suggests future lines of research for preclinical and clinical investigators. We conclude that further investigation into androgenic modulation of opioid receptor mediated effects may lead to new options for addressing conditions such as chronic pain and substance use disorders.

Sex- and Gender-Based Pharmacological Response to Drugs

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

Atheroprotective Properties of Costus spicatus (Jacq.) Sw. in Female Rats

Background: Costus spicatus (Jacq.) Sw. is a medicinal species frequently prescribed for the treatment of cardiovascular diseases. This study aims to evaluate the effects of this species against the development of atherosclerosis. Methods: First, an anatomical study of the C. spicatus leaves was performed. Then, the extract (ESCS) was obtained and submitted to phytochemical analysis. Female rats were treated with a single dose of ESCS (2000 mg/kg) to assess acute toxicity. Other groups of female rats received an atherogenic diet for 60 days. After 30 days, the animals were treated orally with ESCS (30 and 300 mg/kg), rosuvastatin (5 mg/kg), or vehicle once daily for 30 days. Serum lipids oxidized low-density lipoprotein, soluble adhesion molecules, interleukins 1β and 6, and markers of renal and liver function were measured. Renal function, blood pressure, electrocardiography, and vascular reactivity were also evaluated. Arteries, heart, liver, and kidney were also collected to evaluate the tissue redox state and histopathological analysis. Results: Prolonged treatment with ESCS induces significant hypolipidemic and antioxidant effects, that prevent endothelial dysfunction and modulated the local inflammatory process, reducing the evolution of the atherosclerotic disease. Conclusions: This study provides a scientific basis for the popular use of C. spicatus for the treatment of atherosclerosis.

Decreasing myocardial estrogen receptors and antioxidant activity may be responsible for increasing ischemia- and reperfusion-induced ventricular arrhythmia in older female rats

AIMS

This study aimed to investigate the relationship between ischemia- and reperfusion-induced arrhythmia and blood serum estrogen levels, myocardial estrogen receptor levels, antioxidant enzyme activities, and the effects of the estrogen receptor blocker, fulvestrant (ICI 182 780).

MAIN METHODS

A total of 102 female Sprague-Dawley rats of different ages (2-3, 6-7, 14-15, and 20-21 months) were used in this study. Myocardial ischemia was produced by ligation of the descending branch of the left anterior descending coronary artery, and reperfusion was produced by releasing this artery. An electrocardiogram (ECG) and blood pressure were recorded for 6 min of ischemia and 6 min of reperfusion. The levels of superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), estrogen receptor α (ERα), and estrogen receptor β (ERβ) in myocardial tissue and 17 beta-estradiol (E2) in blood serum were measured via enzyme-linked immunosorbent assay (ELISA). The results were compared using a Mann-Whitney U test, one-way analysis of variance (ANOVA), and a student's t-test.

KEY FINDINGS

It is not the changes in serum estrogen levels but the decreasing myocardial estrogen receptors and antioxidant activities that could be responsible for the occurrence of more severe arrhythmia in response to reperfusion in older female rats.

SIGNIFICANCE

The death rate due to a heart attack in younger men is higher than in women. However, it equalizes after the menopausal stage in women. In this study, the reason for the increasing sudden post-menopausal death rate in women was investigated experimentally.

Sex differences in pharmacokinetics predict adverse drug reactions in women

BACKGROUND

Women experience adverse drug reactions, ADRs, nearly twice as often as men, yet the role of sex as a biological factor in the generation of ADRs is poorly understood. Most drugs currently in use were approved based on clinical trials conducted on men, so women may be overmedicated. We determined whether sex differences in drug pharmacokinetics, PKs, predict sex differences in ADRs.

METHODS

Searches of the ISI Web of Science and PubMed databases were conducted with combinations of the terms: drugs, sex or gender, pharmacokinetics, pharmacodynamics, drug safety, drug dose, and adverse drug reaction, which yielded over 5000 articles with considerable overlap. We obtained information from each relevant article on significant sex differences in PK measures, predominantly area under the curve, peak/maximum concentrations, and clearance/elimination rates. ADRs were identified from every relevant article and recorded categorically as female-biased, male-biased, or not sex-biased.

RESULTS

For most of the FDA-approved drugs examined, elevated blood concentrations and longer elimination times were manifested by women, and these PKs were strongly linked to sex differences in ADRs. Of the 86 drugs evaluated, 76 had higher PK values in women; for 59 drugs with clinically identifiable ADRs, sex-biased PKs predicted the direction of sex-biased ADRs in 88% of cases. Ninety-six percent of drugs with female-biased PK values were associated with a higher incidence of ADRs in women than men, but only 29% of male-biased PKs predicted male-biased ADRs. Accessible PK information is available for only a small fraction of all drugs CONCLUSIONS: Sex differences in pharmacokinetics strongly predict sex-specific ADRs for women but not men. This sex difference was not explained by sex differences in body weight. The absence of sex-stratified PK information in public records for hundreds of drugs raises the concern that sex differences in PK values are widespread and of clinical significance. The common practice of prescribing equal drug doses to women and men neglects sex differences in pharmacokinetics and dimorphisms in body weight, risks overmedication of women, and contributes to female-biased adverse drug reactions. We recommend evidence-based dose reductions for women to counteract this sex bias.

Restoration of Adiponectin-Connexin43 Signaling Mitigates Myocardial Inflammation and Dysfunction in Diabetic Female Rats

ur preclinical findings replicated women's hypersensitivity to type-2 diabetes mellitus (T2DM)-evoked cardiac dysfunction along with demonstrating estrogen (E2)-dependent disruption of the cardiac adiponectin (APN)-connexin43 (Cx43) signaling. Whether the latter molecular anomaly underlies this women's cardiovascular health problem remains unknown. We hypothesized that restoration of the disrupted APN-Cx43 signaling alleviates this sex/E2-dependent cardiac dysfunction in diabetic female rats. To test this hypothesis, we administered the adiponectin receptor 1 (AdipoR1) agonist AdipoRon (30 mg/kg/d for 10 days) to female sham operated (SO) and ovariectomized (OVX) rats, which exhibited and lacked the T2DM left ventricular (LV) dysfunction, respectively, when fed high-fat diet and received low dose streptozotocin regimen; nondiabetic control SO and OVX rats received control diet and vehicle for streptozotocin. In T2DM SO rats, LV dysfunction, AdipoRon mitigated: (1) LV hypertrophy, (2) reductions in fractional shortening, LV developed pressure, dP/dtmax, dP/dtmin, and Tau. In LV tissues of the same rats, AdipoRon reversed reduction in Cx43 and elevations in TNFα, heme-oxygenase 1 (HO-1), and circulating cardiovascular risk factor asymmetric dimethylarginine. The findings also revealed ovarian hormones independent effects of AdipoRon, which included dampening of the pro-oxidant enzyme HO-1. These novel findings yield new insight into a causal role for compromised APN-Cx43 signaling in the E2-dependent hypersensitivity to T2DM-evoked cardiac inflammation and dysfunction. Equally important, the findings identify restoration of Cx43 signaling as a viable therapeutic modality for alleviating this women's cardiovascular health-related problem.

Development of a Predictive Model to Induce Atherogenesis and Hepato-Renal Impairment in Female Rats

Therapeutic approaches for the treatment of dyslipidemia and atherosclerosis have radically changed in recent decades. Part of this advance undeniably stems from basic biomedical research that has provided a better understanding and identification of new therapeutic targets. The aim of this work was to develop a model to induce atherogenesis and hepato-renal impairment in female Wistar rats. The following groups received the respective treatments for 60 days: control animals, non-ovariectomized rats that received an atherogenic diet (NEAD), ovariectomized rats that received an atherogenic diet (NOAD), non-ovariectomized rats that received an atherogenic diet and oral Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME; LEAD), and ovariectomized rats that received an atherogenic diet and oral l-NAME (LOAD). Animals in the NEAD, NOAD, LEAD, and LOAD groups also received methimazole and cholecalciferol daily. Urinary, biochemical, hemodynamic, and electrocardiographic parameters and renal function were assessed. Samples of the liver, heart, kidney, and arteries were collected to investigate redox status and perform histopathological analyses. All of the groups developed dyslipidemia and hepatic steatosis. Only the NEAD group developed arterial lesions that were compatible with fatty streaks. Renal function was significantly impaired in the LEAD and NOAD groups. These results indicate a viable alternative to induce atherogenesis and hepato-renal impairment in female rats.

Sex and the kidneys: current understanding and research opportunities

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

Prolonged Exposure to Alcohol Vapor Causes Change in Cardiovascular Function in Female but not in Male Rats

BACKGROUND

Alcohol abuse is a health concern worldwide. Studies have associated alcohol abuse with cardiovascular impairments. In this study, we investigated differences in the effects of chronic alcohol vapor exposure on cardiovascular function between male and female rats by using the alcohol vapor chamber method to induce alcohol addiction-like behaviors in rats.

METHODS

We exposed male and female Long-Evans rats to alcohol vapor for 14 hours, followed by ethanol withdrawal for 10 hours, for 30 consecutive days or room air (control groups). The animals underwent preparation for the surgical implantation of cannulas into femoral vessels, for allowing the assessment of the basal arterial pressure and heart rate values, baroreflex function, and autonomic activity.

RESULTS

Female control rats showed higher basal heart rate compared to male control rats. Chronic alcohol vapor inhalation reduced basal heart rate in females, but not in males; this effect was followed by an increase in the parasympathetic tone of the heart. Further, female rats subjected to alcohol vapor showed an increase in the baroreflex activity.

CONCLUSIONS

These findings suggest that females are more sensitive to chronic alcohol vapor exposure than males because they had a reduction in basal heart rate and changes in the baroreflex activity.

Withdrawal of prenylamine: perspectives on pharmacological, clinical and regulatory outcomes following the first QT-related casualty

Prenylamine, an antianginal agent marketed since early 1960, became the first casualty of QT interval related proarrhythmias in 1988 when it was withdrawn from the market. The period of its synthesis and marketing is of particular interest since it antedated, first, any serious clinical safety concern regarding drug-induced prolongation of the QT interval which was, in fact, believed to be an efficient antiarrhythmic mechanism; second, the first description of torsade de pointes as a unique proarrhythmia, typically associated with prolonged QT interval; and third, the discovery and recognition of calcium antagonism as an important cardiovascular therapeutic strategy. This review, 30 years almost to the day following its withdrawal, provides interesting perspectives on clinical, pharmacological and regulatory outcomes that followed. Prenylamine underscored torsadogenic potential of other early antianginal drugs on the market at that time and identified QT-related proarrhythmias as a much wider major public health issue of clinical and regulatory concern. This resulted in various guidelines for early identification of this potentially fatal risk. Application of these guidelines would have readily identified its proarrhythmic potential. Prenylamine also emphasized differences in drug responses between men and women which subsequently galvanized extensive research into sex-related differences in pharmacology. More importantly, however, investigations into the mechanisms of its action paved the way to developing modern safe and effective calcium antagonists that are so widely used today in cardiovascular pharmacotherapy.