Controversies Regarding Postmenopausal Hormone Replacement Therapy for Primary Cardiovascular Disease Prevention in Women

Vitamin D Status Determines Metformin Action on Gonadotropin Levels in Postmenopausal Women with Subclinical Hyperthyroidism

Background/Objectives: The gonadotropin-lowering effects of metformin were found to be more pronounced in the case of coexisting hyperthyroidism and absent in patients with hypovitaminosis D. Thus, the aim of the current study was to determine whether vitamin D status determines pituitary effects of metformin in individuals with thyroid hyperfunction and elevated gonadotropin levels. Methods: This prospective cohort study included three matched groups of postmenopausal women with hyperthyroidism and prediabetes: women with 25-hydroxyvitamin D levels between 50 and 75 nmol/L (uncompensated vitamin D insufficiency), women with 25-hydroxyvitamin D levels between 75 and 150 nmol/L receiving exogenous calciferol due to previously diagnosed vitamin D deficiency/insufficiency (compensated vitamin D deficiency/insufficiency), and calciferol-naïve subjects with 25-hydroxyvitamin D levels between 75 and 150 nmol/L (the control group). Over the entire study period (six months), all the women were treated with metformin. At the beginning and at the end of this study, we determined 25-hydroxyvitamin D, glucose homeostasis markers, gonadotropins, estradiol, progesterone, TSH, free thyroid hormones, prolactin, ACTH, and IGF-1. Results: Before metformin treatment, except for the 25-hydroxyvitamin D levels, there were no between-group differences in the investigated markers. In all the study groups, metformin reduced plasma glucose, HOMA1-IR, glycated hemoglobin, and FSH, but these effects were more pronounced in both groups of women with normal vitamin D status than in women with uncompensated vitamin D insufficiency. The decrease in LH concentration was observed only in patients with compensated vitamin D deficiency/insufficiency and in the control group. There were no differences between the baseline and follow-up levels of the remaining hormones. The impact of metformin on gonadotropin concentrations positively correlated with their baseline values, free thyroid hormone levels, 25-hydroxyvitamin D levels, and metformin-induced changes in HOMA1-IR. Conclusions: Our findings suggest that low vitamin D status impairs the gonadotropin-lowering effects of metformin in individuals with hyperthyroidism.

Ethics and Academic Discourse, Scientific Integrity, Uncertainty, and Disinformation in Medicine: An American College of Physicians Position Paper

Respect for the scientific process and a diversity of views; open discourse and debate based on principles of ethics, best available evidence, and scientific inquiry and integrity; and an understanding of evidence gaps and uncertainty and how to communicate about them are important values in the advancement of science and the practice of medicine. Physicians often must make decisions about their recommendations to patients in the face of scarce or conflicting data. Are these characteristics of medicine and science widely understood and effectively communicated among members of the profession and to patients and the public? Issues of scientific integrity are longstanding, but COVID-19 brought them to the forefront, in an environment that was sometimes characterized by communication missteps as guidance came and went-or changed-quickly. Today, is open debate flourishing? Have some debates shed more heat than light? Are people losing confidence in science and medicine? In health care institutions? The American College of Physicians explores these issues and offers guidance in this position paper.

Improvement of Cardiovascular Function in Aging Females by the Prolonged Activation of G Protein-Coupled Estrogen Receptor

Ample evidence suggests that estrogen replacement therapy is associated with beneficial effects with regard to cardiovascular diseases when the therapy is initiated temporally close to menopause but not when it is initiated later. Little is known about the complex interactions between hormone receptors after menopause. Coronary artery function and cardiac function were measured in rats that had either received no treatment or had been pretreated with an androgen receptor (AR) antagonist and/or a GPER agonist G-1. ICI 182,780 was used to block the classical estrogen receptors (ERs) to investigate their complex interactions with GPER. The beneficial effects of GPER were only observed by blocking ARs and classical ERs in aged female rats. The results demonstrate that GPER activation is a potential therapeutic target for the inhibition of age-dependent coronary artery dysfunction and cardiac dysfunction under the condition of blocking ARs and classical ERs after menopause. CLINICAL RELEVANCE: The risk of cardiovascular disease in postmenopausal women significantly increased. The role of sex hormones and their receptors during this process is still complicated. Our present study demonstrated that the imbalance of androgen and estrogen may contribute to the impairment of vascular reactivity and subsequent cardiac function. Treatment with GPER agonist G1 combined with the inhibition of ERα and ERβ could improve vascular function and reduce the myocardial ischemia reperfusion injury. These findings may provide the novel and effective strategy for the treatment of cardiovascular diseases in postmenopausal women.

Sex Differences and Regulatory Actions of Estrogen in Cardiovascular System

Great progress has been made in the understanding of the pathophysiology of cardiovascular diseases (CVDs), and this has improved the prevention and prognosis of CVDs. However, while sex differences in CVDs have been well documented and studied for decades, their full extent remains unclear. Results of the latest clinical studies provide strong evidence of sex differences in the efficacy of drug treatment for heart failure, thereby possibly providing new mechanistic insights into sex differences in CVDs. In this review, we discuss the significance of sex differences, as rediscovered by recent studies, in the pathogenesis of CVDs. First, we provide an overview of the results of clinical trials to date regarding sex differences and hormone replacement therapy. Then, we discuss the role of sex differences in the maintenance and disruption of cardiovascular tissue homeostasis.