Estrogen Receptor-α Genotype Affects Exercise-Related Reduction of Arterial Stiffness

Mineralocorticoid and estrogen receptors as sex-dependent modulators of vascular health in aging and obesity

Cardiovascular disease (CVD) is the leading cause of death in both men and women, but there are sex differences in the timing and mechanisms of disease development. Sex differences particularly influence the development of CVD in the presence of aging and obesity, 2 major risk factors of CVD. The mineralocorticoid and estrogen receptors have been identified as important regulators of vascular function in healthy and disease states. Recent evidence has highlighted interactions between these receptors in the vasculature, and innovations in global and cell-specific knockout mouse models have substantially advanced our understanding of sex-dependent roles of these receptors in vascular health and disease. This review summarizes recent advances in the sex-dependent roles of the mineralocorticoid and estrogen receptors in arterial stiffness and vasomotor dysfunction, 2 early markers of CVD development. These vascular outcomes are examined in the context of aging and obesity, 2 of the most prevalent CVD risk factors. SIGNIFICANCE STATEMENT: Cardiovascular disease (CVD) is the leading cause of death globally for women and men, but there are sex differences in the timing of CVD development across the lifespan and in mechanisms driving disease. This review summarizes sex-specific roles of mineralocorticoid and estrogen receptors in arterial stiffness and vasomotor dysfunction during aging and obesity. Understanding sex-specific mechanisms of CVD is critical to developing precision medicine strategies to prevent and treat CVD in women and men.

Relationship between objectively measured physical activity and subclinical cardiovascular disease: a systematic review

Introduction

The association of physical activity (PA) with subclinical cardiovascular disease (CVD) is unclear. Clarifying this relationship may inform cardiovascular prevention strategies.

Methods

We performed a systematic review (CRD42021226089) using Medline, Embase, CINAHL and Cochrane (1 January 2000 to 1 September 2023). Studies published with adult populations exploring the relationship between objectively measured PA and subclinical CVD were included. Subclinical CVD was assessed using: ankle-brachial index (ABI); arterial stiffness; carotid artery disease; coronary artery atherosclerosis; endothelial function; and measures of cardiac structure and function. The Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) and Cochrane Risk of Bias tools were used for quality review.

Results

Of 68 included studies, most supported an inverse relationship between PA and subclinical CVD. Arterial stiffness was the most common outcome (n=40), and 33 studies suggested that less sedentary behaviour (SB), increased PA and/or higher intensity PA was associated with less arterial stiffness. Ten studies of carotid artery disease (total n=18), six of endothelial function (n=10), two of coronary artery disease (n=3) and all of ABI (n=6) suggested that PA or less SB is associated with less subclinical disease. Five studies assessing cardiac structure/function (n=6) suggested alterations in structure/function with PA.

Conclusions

PA reduces the risk of CVD events, and this systematic review demonstrates that some of the benefits may be mediated by an inverse association between PA and subclinical CVD. Interventions to increase PA are important for CVD prevention, so we provide a comprehensive overview of which surrogate outcome measures may be most useful to assess future CVD prevention interventions.

PROSPERO registration number

CRD42021226089.

Equol-producing status affects exercise training-induced improvement in arterial compliance in postmenopausal women

Central arterial compliance decreases drastically after menopause. Regular intake of soy isoflavone and aerobic exercise increase arterial compliance. The equol is a metabolite of isoflavone daidzein by gut microbiome. We determined whether the equol-producing status affects aerobic exercise-induced improvement in carotid arterial compliance. Forty-three postmenopausal women were assigned to two intervention groups: 1) exercise and isoflavone (Ex+Iso, n = 27 females) or 2) isoflavone interventions (Iso; n = 16 females). Participants of the Ex+Iso intervention group completed an 8-wk aerobic exercise training, and all participants were administered with oral isoflavone supplements during the interventions. The equol-producing status (equol producers or nonproducers) was determined from urine equol concentrations after a soy challenge. In the Ex+Iso intervention group, carotid arterial compliance increased in the equol producers (0.084 ± 0.030→0.117 ± 0.035 mm²/mmHg), but not in the nonproducers (0.089 ± 0.028→0.097 ± 0.026 mm²/mmHg) after the intervention (interaction effect; P < 0.05). The magnitude of increases in carotid arterial compliance was significantly greater in the equol producers than in the non-equol producers (P < 0.05). In the isoflavone intervention group, there were no changes in any parameters after the intervention irrespective of the equol status. These results suggest that equol-producing status is obligatory to aerobic exercise training-induced improvements in central arterial compliance in postmenopausal women.NEW & NOTEWORTHY Isoflavone intake and aerobic exercise increase central artery compliance. Equol, a metabolite of isoflavone daidzein by gut microbiome, has beneficial effects on vascular function. We demonstrated for the first time that the interaction of aerobic exercise and equol production status plays an essential role in improvements in central artery compliance in postmenopausal women. More specifically, the equol-producing status was obligatory to exercise training-induced improvements in central arterial compliance in postmenopausal women.

Estrogen receptor-α signaling maintains immunometabolic function in males and is obligatory for exercise-induced amelioration of nonalcoholic fatty liver

The role of estrogen receptor-α (ERα) signaling in immunometabolic function is established in females. However, its necessity in males, while appreciated, requires further study. Accordingly, we first determined whether lower metabolic function in male mice compared with females is related to reduced ERα expression. ERα protein expression in metabolically active tissues was lower in males than in females, and this lower expression was associated with worse glucose tolerance. Second, we determined whether ERα is required for optimal immunometabolic function in male mice consuming a chow diet. Despite lower expression of ERα in males, its genetic ablation (KO) caused an insulin-resistant phenotype characterized by enhanced adiposity, glucose intolerance, hepatic steatosis, and metaflammation in adipose tissue and liver. Last, we determined whether ERα is essential for exercise-induced metabolic adaptations. Twelve-week-old wild-type (WT) and ERα KO mice either remained sedentary (SED) or were given access to running wheels (WR) for 10 wk while fed an obesogenic diet. Body weight and fat mass were lower in WR mice regardless of genotype. Daily exercise obliterated immune cell infiltration and inflammatory gene transcripts in adipose tissue in both genotypes. In the liver, however, wheel running suppressed hepatic steatosis and inflammatory gene transcripts in WT but not in KO mice. In conclusion, the present findings indicate that ERα is required for optimal immunometabolic function in male mice despite their reduced ERα protein expression in metabolically active tissues. Furthermore, for the first time, we show that ERα signaling appears to be obligatory for exercise-induced prevention of hepatic steatosis.

Effects of endothelin-related gene polymorphisms and aerobic exercise habit on age-related arterial stiffening: a 10-yr longitudinal study

Increased arterial stiffness has emerged as a strong predictor of future cardiovascular events and all-cause mortality. The aim of this study was to elucidate influences of endothelin (ET)-related genetic polymorphisms and regular physical activity on age-related arterial stiffening through a 10-yr longitudinal study. A decadal change in brachial-ankle pulse wave velocity (baPWV), an index of arterial stiffness, was evaluated retrospectively among 92 volunteers (63 ± 14 yr, 51 men). The targeted single-nucleotide polymorphisms were ET-A receptor SNP rs5333 (ET-A) and ET-B receptor SNP rs5351 (ET-B). Subjects with either ET-A TC or CC genotypes exhibited significantly greater increases in baPWV (+15.3 ± 11.7 and +16.6 ± 15.7%/dec, respectively) than ET-A TT genotype holders (+9.2 ± 9.0%/dec), whereas subjects with the ET-B GG genotype showed a significantly greater increase in baPWV (+17.7 ± 14.1%/dec) than other ET-B genotype holders (AA: +9.5 ± 10.0%/dec; AG: +11.2 ± 9.6%/dec). The combination of these ET-related genetic risks was associated with a 2.4 times greater decadal increase in baPWV compared with no genetic risk (+8.1 ± 8.4 vs. 19.5 ± 16.0%/dec). In contrast, individuals engaging in >15 METs·h/wk of aerobic exercise showed substantially smaller increases in baPWV (+5.0 ± 9.7%/dec) compared with their physically inactive peers (approximately +13%/dec). These differences remained significant after adjusting for confounding factors, including baseline baPWV and ET-related genotype risk. Our current longitudinal study found that ET-related gene polymorphisms contribute to diverse age-related changes in arterial stiffness, and that regular sufficient aerobic exercise attenuates the age-related arterial stiffening independently of ET-related gene polymorphisms. NEW & NOTEWORTHY This 10-yr longitudinal study suggests that endothelin-related gene polymorphisms contribute to divergent increases in arterial stiffness with advancing age, whereas regular sufficient aerobic exercise attenuates age-related arterial stiffening independently of ET-related gene polymorphisms. This notion partly supports prevailing evidence that regular aerobic exercise contributes to a lower incidence of cardiovascular disease.

Influence of aerobic exercise training on post-exercise responses of aortic pulse pressure and augmentation pressure in postmenopausal women

Central arterial blood pressure (BP) is more predictive of future cardiovascular events than is brachial BP because it reflects the BP load imposed on the left ventricle with greater accuracy. However, little is known about the effects of exercise training on central hemodynamic response to acute exercise. The purpose of the present study was to determine the influence of an aerobic exercise regimen on the response of aortic BP after a single aerobic exercise in postmenopausal women. Nine healthy postmenopausal women (age: 61 ± 2 years) participated in a 12-week aerobic exercise training regimen. Before and after the training, each subjects performed a single bout of cycling at ventilatory thresholds for 30 min. We evaluated the post-exercise aortic BP response, which was estimated via the general transfer function from applanation tonometry. After the initial pre-training aerobic exercise session, aortic BP did not change significantly: however, aortic pulse pressure and augmentation pressure were significantly attenuated after the single aerobic exercise session following the 12-week training regimen. The present study demonstrated that a regular aerobic exercise training regimen induced the post-exercise reduction of aortic pulse pressure and augmentation pressure. Regular aerobic exercise training may enhance post-exercise reduction in aortic BP.

Vascular adaptations to hypobaric hypoxic training in postmenopausal women

The objective of this study was to examine the effects of exercise training in hypoxia on arterial stiffness and flow-mediated vasodilation (FMD) in postmenopausal women. Sixteen postmenopausal women (56±1 years) were assigned to a normoxic exercise group (Normoxic group, n=8) or a hypoxic exercise group (Hypoxic group, n=8). The Hypoxic group performed exercise under hypobaric hypoxic conditions corresponding to 2000 m above sea level, and was exposed to these conditions for 2 h per session. Aquatic exercise was performed at an intensity of around 50% peak oxygen uptake for 30min, 4days per week, for 8 weeks. Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV), and FMD was evaluated by peak diameter of the popliteal artery during reactive hyperemia. After the 8 weeks of training, the Normoxic group showed no significant changes. In contrast, baPWV (P < 0.05) was significantly reduced and peak diameter (P<0.05) and %FMD (P<0.01) were significantly increased in the Hypoxic group after training. These results suggest that exercise training under mild intermittent hypoxic conditions could more effectively reduce arterial stiffness in postmenopausal women, compared with exercise training performed at the same relative intensity under normoxic conditions. Our data also indicate that hypoxic exercise training may induce vascular functional adaptation, for example an increase in FMD response. These findings therefore could have important implications for the development of a new effective exercise prescription program.

Genetics and pathophysiology of arterial stiffness

Arterial stiffness is a cardiovascular risk factor that is independent of arterial pressure. Clinically, carotid-femoral pulse wave velocity (PWV) is the gold-standard parameter of arterial stiffness. Recent genetic studies have revealed specific genes that contribute to arterial stiffening. Here we review the recent findings on genome-wide linkage analyses and candidate gene polymorphism association studies. We also focus on the latest advances in the identification of gene variants affecting PWV using high density array single nucleotide polymorphism technology in a recent genome-wide association (GWA) study. Linkage and polymorphism studies revealed a first group of genes affecting the renin-angiotensin-aldosterone system, elastic fibre structural components, metalloproteinases, and the NO pathway. A second group of genes, identified by polymorphism association studies and possibly involved in the pathophysiology of arterial stiffness, includes beta-adrenergic receptors, endothelin receptors, and inflammatory molecules. The last group of genes, identified by GWA studies and unrelated to currently suspected mechanisms of arterial stiffness, may target transcriptional pathways controlling gene expression, differentiation of vascular smooth muscle cells, apoptosis of endothelial cells, or the immune response within the vascular wall.