Ascorbic acid selectively improves large elastic artery compliance in postmenopausal women

Socioeconomic status as a potential mediator of arterial aging in marginalized ethnic and racial groups: current understandings and future directions

Cardiovascular diseases (CVDs) are the leading cause of death in the United States. However, disparities in CVD-related morbidity and mortality exist as marginalized racial and ethnic groups are generally at higher risk for CVDs (Black Americans, Indigenous People, South and Southeast Asians, Native Hawaiians, and Pacific Islanders) and/or development of traditional CVD risk factors (groups above plus Hispanics/Latinos) relative to non-Hispanic Whites (NHW). In this comprehensive review, we outline emerging evidence suggesting these groups experience accelerated arterial dysfunction, including vascular endothelial dysfunction and large elastic artery stiffening, a nontraditional CVD risk factor that may predict risk of CVDs in these groups with advancing age. Adverse exposures to social determinants of health (SDOH), specifically lower socioeconomic status (SES), are exacerbated in most of these groups (except South Asians-higher SES) and may be a potential mediator of accelerated arterial aging. SES negatively influences the ability of marginalized racial and ethnic groups to meet aerobic exercise guidelines, the first-line strategy to improve arterial function, due to increased barriers, such as time and financial constraints, lack of motivation, facility access, and health education, to performing conventional aerobic exercise. Thus, identifying alternative interventions to conventional aerobic exercise that 1) overcome these common barriers and 2) target the biological mechanisms of aging to improve arterial function may be an effective, alternative method to aerobic exercise to ameliorate accelerated arterial aging and reduce CVD risk. Importantly, dedicated efforts are needed to assess these strategies in randomized-controlled clinical trials in these marginalized racial and ethnic groups.

Effects of regular exercise on vascular function with aging: Does sex matter?

Vascular aging, featuring endothelial dysfunction and large elastic artery stiffening, is a major risk factor for the development of age-associated cardiovascular diseases (CVDs). Vascular aging is largely mediated by an excessive production of reactive oxygen species (ROS) and increased inflammation leading to reduced bioavailability of the vasodilatory molecule nitric oxide and remodeling of the arterial wall. Other cellular mechanisms (i.e., mitochondrial dysfunction, impaired stress response, deregulated nutrient sensing, cellular senescence), termed "hallmarks" or "pillars" of aging, may also contribute to vascular aging. Gonadal aging, which largely impacts women but also impacts some men, modulates the vascular aging process. Regular physical activity, including both aerobic and resistance exercise, is a first-line strategy for reducing CVD risk with aging. Although exercise is an effective intervention to counter vascular aging, there is considerable variation in the vascular response to exercise training with aging. Aerobic exercise improves large elastic artery stiffening in both middle-aged/older men and women and enhances endothelial function in middle-aged/older men by reducing oxidative stress and inflammation and preserving nitric oxide bioavailability; however, similar aerobic exercise training improvements are not consistently observed in estrogen-deficient postmenopausal women. Sex differences in adaptations to exercise may be related to gonadal aging and declines in estrogen in women that influence cellular-molecular mechanisms, disconnecting favorable signaling in the vasculature induced by exercise training. The present review will summarize the current state of knowledge on vascular adaptations to regular aerobic and resistance exercise with aging, the underlying mechanisms involved, and the moderating role of biological sex.

Estrogen and the Vascular Endothelium: The Unanswered Questions

Premenopausal women have a lower incidence of cardiovascular disease (CVD) compared with their age-matched male counterparts; however, this discrepancy is abolished following the transition to menopause or during low estrogen states. This, combined with a large amount of basic and preclinical data indicating that estrogen is vasculoprotective, supports the concept that hormone therapy could improve cardiovascular health. However, clinical outcomes in individuals undergoing estrogen treatment have been highly variable, challenging the current paradigm regarding the role of estrogen in the fight against heart disease. Increased risk for CVD correlates with long-term oral contraceptive use, hormone replacement therapy in older, postmenopausal cisgender females, and gender affirmation treatment for transgender females. Vascular endothelial dysfunction serves as a nidus for the development of many cardiovascular diseases and is highly predictive of future CVD risk. Despite preclinical studies indicating that estrogen promotes a quiescent, functional endothelium, it still remains unclear why these observations do not translate to improved CVD outcomes. The goal of this review is to explore our current understanding of the effect of estrogen on the vasculature, with a focus on endothelial health. Following a discussion regarding the influence of estrogen on large and small artery function, critical knowledge gaps are identified. Finally, novel mechanisms and hypotheses are presented that may explain the lack of cardiovascular benefit in unique patient populations.

Aging, aerobic exercise, and cardiovascular health: Barriers, alternative strategies and future directions

Age-associated cardiovascular (CV) dysfunction, namely arterial dysfunction, is a key antecedent to the development of CV disease (CVD). Arterial dysfunction with aging is characterized by impaired vascular endothelial function and stiffening of the large elastic arteries, each of which is an independent predictor of CVD. These processes are largely mediated by an excess production of reactive oxygen species (ROS) and an increase in chronic, low-grade inflammation that ultimately leads to a reduction in bioavailability of the vasodilatory molecule nitric oxide. Additionally, there are other fundamental aging mechanisms that may contribute to excessive ROS and inflammation termed the "hallmarks of aging"; these additional mechanisms of arterial dysfunction may represent therapeutic targets for improving CV health with aging. Aerobic exercise is the most well-known and effective intervention to prevent and treat the effects of aging on CV dysfunction. However, the majority of mid-life and older (ML/O) adults do not meet recommended exercise guidelines due to traditional barriers to aerobic exercise, such as reduced leisure time, motivation, or access to fitness facilities. Therefore, it is a biomedical research priority to develop and implement time- and resource-efficient alternative strategies to aerobic exercise to reduce the burden of CVD in ML/O adults. Alternative strategies that mimic or are inspired by aerobic exercise, that target pathways specific to the fundamental mechanisms of aging, represent a promising approach to accomplish this goal.

Pyridoxamine treatment ameliorates large artery stiffening and cerebral artery endothelial dysfunction in old mice

Age-related increases in large artery stiffness are associated with cerebrovascular dysfunction and cognitive impairment. Pyridoxamine treatment prevents large artery stiffening with advancing age, but the effects of pyridoxamine treatment on the cerebral vasculature or cognition is unknown. The purpose of this study was to investigate the effects of pyridoxamine on blood pressure, large artery stiffness, cerebral artery function, and cognitive function in old mice. Old male C57BL/6 mice consumed either pyridoxamine (2 g/L) or vehicle control in drinking water for ∼7.5 months and were compared with young male C57BL/6 mice. From pre- to post-treatment, systolic blood pressure increased in old control mice, but was maintained in pyridoxamine treated mice. Large artery stiffness decreased in pyridoxamine-treated mice but was unaffected in control mice. Pyridoxamine-treated mice had greater cerebral artery endothelium-dependent dilation compared with old control mice, and not different from young mice. Old control mice had impaired cognitive function; however, pyridoxamine only partially preserved cognitive function in old mice. In summary, pyridoxamine treatment in old mice prevented age-related increases in blood pressure, reduced large artery stiffness, preserved cerebral artery endothelial function, and partially preserved cognitive function. Taken together, these results suggest that pyridoxamine treatment may limit vascular aging.

Role of BH4 deficiency as a mediator of oxidative stress-related endothelial dysfunction in menopausal women

Endothelial function (brachial artery flow-mediated dilation [FMD]) is reduced in estrogen-deficient postmenopausal women, mediated, in part, by reduced nitric oxide (NO) bioavailability, secondary to tetrahydrobiopterin (BH4) deficiency and oxidative stress. FMD is increased, but not fully restored, in postmenopausal women after acute intravenous vitamin C (VITC; superoxide scavenger) or oral BH4 supplementation. In vitro studies demonstrate that coadministration of VITC with BH4 prevents endothelial nitric oxide synthase (eNOS) uncoupling and reductions in NO by peroxynitrite. To investigate mechanisms of endothelial dysfunction in women, we assessed the separate and combined effects of VITC and BH4 to determine whether coadministration of VITC + BH4 improves FMD in healthy postmenopausal women (n = 19, 58 ± 5 yr) to premenopausal (n = 14, 36 ± 9 yr) levels, with exploratory testing in perimenopausal women (n = 8, 51 ± 3 yr). FMD was measured during acute intravenous infusions of saline (control) and VITC (∼2-3 g) ∼3 h after a single dose of oral BH4 (KUVAN, 10 mg/kg body wt) or placebo (randomized crossover, separated by ∼1 mo). Under the placebo condition, FMD was reduced in postmenopausal compared with premenopausal women during the saline infusion (5.6 ± 0.7 vs. 11.6 ± 0.9%, P < 0.001) and increased in postmenopausal women during VITC (+3.5 [1.4, 5.6]%, P = 0.001) and acute BH4 (+1.8 [0.37, 3.2]%, P = 0.01) alone. Coadministration of VITC + BH4 increased FMD in postmenopausal women (+3.0 [1.7, 4.3]%, P < 0.001), but FMD remained reduced compared with premenopausal women (P = 0.02). Exploratory analyses revealed that VITC + BH4 did not restore FMD in perimenopausal women to premenopausal levels (P = 0.045). Coadministration of VITC + BH4 does not restore FMD in menopausal women, suggesting that additional mechanisms may be involved.NEW & NOTEWORTHY Endothelial function is reduced across the menopausal stages related to increased oxidative stress associated with estrogen deficiency. In vitro studies demonstrate that coadministration of VITC with BH4 prevents endothelial nitric oxide synthase (eNOS) uncoupling and reductions in NO by peroxynitrite; however, this remains untested in humans. We demonstrate that the coadministration of BH4 + VITC does not restore endothelial function in perimenopausal and postmenopausal women to the level of premenopausal women, suggesting that other mechanisms contribute.

Seven days of statin treatment improves nitric-oxide mediated endothelial-dependent cutaneous microvascular function in women with endometriosis

INTRODUCTION

Endometriosis is associated with systemic inflammation and increased risk of cardiovascular disease (CVD). Endothelial dysfunction is one of the first manifestations of CVD but is unexplored in women with endometriosis. HMG-CoA-reductase inhibitors (statins) exert potent anti-inflammatory effects, and have been proposed as an adjunctive therapy in women with endometriosis. We hypothesized that microvascular endothelial function would be impaired in otherwise healthy women with endometriosis mediated by reduced nitric oxide (NO)-dependent dilation and that short term statin administration would improve endothelial function.

METHODS

In 8 healthy control (HC: 33 ± 9 yr) and 8 women with endometriosis (EN: 34 ± 9 yr), laser-Doppler flux (LDF) was measured continuously during graded intradermal microdialysis perfusion of the endothelium-dependent agonist acetylcholine (Ach: 10-10-10-1 M) alone and in combination with the NO synthase inhibitor (L-NAME: 0.015 M). 6 EN repeated the microdialysis experiment following 7 days of oral atorvastatin treatment (10 mg). Cutaneous vascular conductance was calculated (CVC = LDF*mmHg-1) and normalized to site-specific maximum (28 mM sodium nitroprusside, 43 °C). The NO-dependent dilation was calculated as the difference between the areas under the dose response curves.

RESULTS

Ach-induced vasodilation was blunted in women with endometriosis (main effect p < 0.01), indicating impaired endothelial function. NO-dependent vasodilation was also reduced in women with endometriosis (HC: 217 ± 120.3 AUC vs. EN: 88 ± 97 AUC, p = 0.03). Oral atorvastatin improved Ach-induced (main effect p < 0.01) and NO-dependent (295 ± 153 AUC; p = 0.05) vasodilation in women with endometriosis.

CONCLUSION

Microcirculatory endothelium-dependent vasodilation is impaired in women with endometriosis, mediated in part by reductions in NO. Short-term oral atorvastatin improved endothelium-dependent vasodilation, suggesting that statin therapy may be a viable intervention strategy to mitigate accelerated CVD risk in women with endometriosis.

Comparison of Blood Pressure and Vascular Health in Physically Active Late Pre- and Early Postmenopausal Females

PURPOSE

The benefits of exercise on vascular health are inconsistent in postmenopausal females. We investigated if blood pressure and markers of vascular function differ between physically active early post- and late premenopausal females.

METHODS

We performed a cross-sectional comparison of 24-h blood pressure, brachial artery flow-mediated dilation, microvascular reactivity (reactive hyperemia), carotid-femoral pulse wave velocity, and cardiac baroreflex sensitivity between physically active late premenopausal (n = 16, 48 ± 2 yr) and early postmenopausal (n = 14, 53 ± 2 yr) females.

RESULTS

Physical activity level was similar between premenopausal (490 ± 214 min·wk-1) and postmenopausal (550 ± 303 min·wk-1) females (P = 0.868). Brachial artery flow-mediated dilation (pre, 4.6 ± 3.9, vs post, 4.7% ± 2.2%; P = 0.724), 24-h systolic (+5 mm Hg, 95% confidence interval [CI] = -1 to +10, P = 0.972) and diastolic (+4 mm Hg, 95% CI = -1 to +9, P = 0.655) blood pressures, total reactive hyperemia (pre, 1.2 ± 0.5, vs post, 1.0 ± 0.5 mL·mm Hg-1; P = 0.479), carotid-femoral pulse wave velocity (pre, 7.9 ± 1.7, vs post, 8.1 ± 1.8 m·s-1; P = 0.477), and cardiac baroreflex sensitivity (-8 ms·mm Hg-1, 95% CI = -20.55 to 4.62, P = 0.249) did not differ between groups. By contrast, peak reactive hyperemia (-0.36 mL·min-1⋅mm Hg-1, 95% CI = -0.87 to +0.15, P = 0.009) was lower in postmenopausal females.

CONCLUSIONS

These results suggest that blood pressure and markers of vascular function do not differ between physically active late pre- and early postmenopausal females.

Noncoding RNAs in age-related cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality in the adult population worldwide and represent a severe economic burden and public health concern. The majority of human genes do not code for proteins. However, noncoding transcripts play important roles in ageing that significantly increases the risk for CVDs. Noncoding RNAs (ncRNAs) are critical regulators of multiple biological processes related to ageing such as oxidative stress, mitochondrial dysfunction and chronic inflammation. NcRNAs are also involved in pathophysiological developments within the cardiovascular system including arrhythmias, cardiac hypertrophy, fibrosis, myocardial infarction and heart failure. In this review article, we cover the roles of ncRNAs in cardiovascular ageing and disease as well as their potential therapeutic applications in CVDs.

Is It Good to Have a Stiff Aorta with Aging? Causes and Consequences

Aortic stiffness increases with advancing age, more than doubling during the human life span, and is a robust predictor of cardiovascular disease (CVD) clinical events independent of traditional risk factors. The aorta increases in diameter and length to accommodate growing body size and cardiac output in youth, but in middle and older age the aorta continues to remodel to a larger diameter, thinning the pool of permanent elastin fibers, increasing intramural wall stress and resulting in the transfer of load bearing onto stiffer collagen fibers. Whereas aortic stiffening in early middle age may be a compensatory mechanism to normalize intramural wall stress and therefore theoretically "good" early in the life span, the negative clinical consequences of accelerated aortic stiffening beyond middle age far outweigh any earlier physiological benefit. Indeed, aortic stiffness and the loss of the "windkessel effect" with advancing age result in elevated pulsatile pressure and flow in downstream microvasculature that is associated with subclinical damage to high-flow, low-resistance organs such as brain, kidney, retina, and heart. The mechanisms of aortic stiffness include alterations in extracellular matrix proteins (collagen deposition, elastin fragmentation), increased arterial tone (oxidative stress and inflammation-related reduced vasodilators and augmented vasoconstrictors; enhanced sympathetic activity), arterial calcification, vascular smooth muscle cell stiffness, and extracellular matrix glycosaminoglycans. Given the rapidly aging population of the United States, aortic stiffening will likely contribute to substantial CVD burden over the next 2-3 decades unless new therapeutic targets and interventions are identified to prevent the potential avalanche of clinical sequelae related to age-related aortic stiffness.

Oxidative Stress and Inflammation Are Associated With Age-Related Endothelial Dysfunction in Men With Low Testosterone

CONTEXT

Vascular aging, including endothelial dysfunction secondary to oxidative stress and inflammation, increases the risk for age-associated cardiovascular disease (CVD). Low testosterone in middle-aged/older men is associated with increased CVD risk.

OBJECTIVE

We hypothesized that low testosterone contributes to age-associated endothelial dysfunction, related in part to greater oxidative stress and inflammation.

METHODS

This cross-sectional study included 58 healthy, nonsmoking men categorized as young (N = 20; age 29 ± 4 years; testosterone 500 ± 58 ng/dL), middle-aged/older with higher testosterone (N = 20; age 60 ± 6 years; testosterone 512 ± 115 ng/dL), and middle-aged/older lower testosterone (N = 18; age 59 ± 8 years; testosterone 269 ± 48 ng/dL). Brachial artery flow-mediated dilation (FMDBA) was measured during acute infusion of saline (control) and vitamin C (antioxidant). Markers of oxidative stress (total antioxidant status and oxidized low-density lipoprotein cholesterol), inflammation (interleukin [IL]-6 and C-reactive protein [CRP]), and androgen deficiency symptoms were also examined.

RESULTS

During saline, FMDBA was reduced in middle-aged/older compared with young, regardless of testosterone status (P < 0.001). FMDBA was reduced in middle-aged/older lower testosterone (3.7% ± 2.0%) compared with middle-aged/older higher testosterone (5.7% ± 2.2%; P = 0.021), independent of symptoms. Vitamin C increased FMDBA (to 5.3% ± 1.6%; P = 0.022) in middle-aged/older lower testosterone but had no effect in young (P = 0.992) or middle-aged/older higher testosterone (P = 0.250). FMDBA correlated with serum testosterone (r = 0.45; P < 0.001), IL-6 (r = -0.41; P = 0.002), and CRP (r = -0.28; P = 0.041).

CONCLUSION

Healthy middle-aged/older men with low testosterone appear to have greater age-associated endothelial dysfunction, related in part to greater oxidative stress and inflammation. These data suggest that low testosterone concentrations may contribute to accelerated vascular aging in men.

Body composition and cardiometabolic health across the menopause transition

Every year, 2 million women reach menopause in the United States, and they may spend 40% or more of their life in a postmenopausal state. In the years immediately preceding menopause-known as the menopause transition (or perimenopause)-changes in hormones and body composition increase a woman's overall cardiometabolic risk. In this narrative review, we summarize the changes in weight, body composition, and body fat distribution, as well as the changes in energy intake, energy expenditure, and other cardiometabolic risk factors (lipid profile, glucose metabolism, sleep health, and vascular function), that occur during the menopause transition. We also discuss the benefits of lifestyle interventions in women in the earlier stages of menopause before these detrimental changes occur. Finally, we discuss how to include perimenopausal women in research studies so that women across the life-span are adequately represented.

The Mechanobiology of Vascular Remodeling in the Aging Lung

Aging is accompanied by declining lung function and increasing susceptibility to lung diseases. The role of endothelial dysfunction and vascular remodeling in these changes is supported by growing evidence, but underlying mechanisms remain elusive. In this review we summarize functional, structural, and molecular changes in the aging pulmonary vasculature and explore how interacting aging and mechanobiological cues may drive progressive vascular remodeling in the lungs.

Sex Differences in Large Artery Stiffness: Implications for Cerebrovascular Dysfunction and Alzheimer’s Disease

Two in every three Alzheimer’s disease diagnoses are females, calling attention to the need to understand sexual dimorphisms with aging and neurodegenerative disease progression. Dysfunction and damage to the vasculature with aging are strongly linked to Alzheimer’s disease. With aging there is an increase in stiffness of the large elastic arteries, and this stiffening is associated with cerebrovascular dysfunction and cognitive impairment. However, it is unclear how the deleterious effects of arterial stiffness may differ between females and males. While environmental, chromosomal, and sex hormone factors influence aging, there is evidence that the deficiency of estrogen post-menopause in females is a contributor to vascular aging and Alzheimer’s disease progression. The purpose of this mini review is to describe the recent developments in our understanding of sex differences in large artery stiffness, cerebrovascular dysfunction, and cognitive impairment, and their intricate relations. Furthermore, we will focus on the impact of the loss of estrogen post-menopause as a potential driving factor for these outcomes. Overall, a better understanding of how sex differences influence aging physiology is crucial to the prevention and treatment of neurodegenerative diseases.

Oral vitamin C restores endothelial function during acute inflammation in young and older adults

Oxidative stress has been linked to reductions in vascular function during acute inflammation in young adults; however, the effect of acute inflammation on vascular function with aging is inconclusive. The aim of this study was to determine if oral antioxidant administration eliminates vascular dysfunction during acute inflammation in young and older adults. Brachial flow-mediated dilation (FMD) and carotid-femoral pulse wave velocity (PWV) were measured in nine young (3 male, 24 ± 4 yrs, 26.2 ± 4.9 kg/m2 ) and 16 older (13 male, 64 ± 5 yrs, 25.8 ± 3.2 kg/m2 ) adults before and 2-h after oral consumption of 2 g of vitamin C. The vitamin C protocol was completed at rest and 24 h after acute inflammation was induced via the typhoid vaccine. Venous blood samples were taken to measure markers of inflammation and vitamin C. Both interleukin-6 (Δ+0.7 ± 1.8 pg/ml) and C-reactive protein (Δ+1.9 ± 3.1 mg/L) were increased at 24 h following the vaccine (p < 0.01). There was no change in FMD or PWV following vitamin C administration at rest (p > 0.05). FMD was lower in all groups during acute inflammation (Δ-1.4 ± 1.9%, p < 0.01), with no changes in PWV (Δ-0.0 ± 0.9 m/s, p > 0.05). Vitamin C restored FMD back to initial values in young and older adults during acute inflammation (Δ+1.0 ± 1.8%, p < 0.01) with no change in inflammatory markers or PWV (p > 0.05). In conclusion, oral vitamin C restored endothelial function during acute inflammation in young and older adults, with no effect on aortic stiffness. The effect of vitamin C on endothelial function did not appear to be due to reductions in inflammatory markers. The exact mechanisms should be further investigated.

Ascorbic Acid Prevents Vascular Endothelial Dysfunction Induced by Electronic Hookah (Waterpipe) Vaping

Background Electronic hookah (e-hookah) vaping has increased in popularity among youth, who endorse unsubstantiated claims that flavored aerosol is detoxified as it passes through water. However, e-hookahs deliver nicotine by creating an aerosol of fine and ultrafine particles and other oxidants that may reduce the bioavailability of nitric oxide and impair endothelial function secondary to formation of oxygen-derived free radicals. Methods and Results We examined the acute effects of e-hookah vaping on endothelial function, and the extent to which increased oxidative stress contributes to the vaping-induced vascular impairment. Twenty-six healthy young adult habitual hookah smokers were invited to vape a 30-minute e-hookah session to evaluate the impact on endothelial function measured by brachial artery flow-mediated dilation (FMD). To test for oxidative stress mediation, plasma total antioxidant capacity levels were measured and the effect of e-hookah vaping on FMD was examined before and after intravenous infusion of the antioxidant ascorbic acid (n=11). Plasma nicotine and exhaled carbon monoxide levels were measured before and after the vaping session. Measurements were performed before and after sham-vaping control experiments (n=10). E-hookah vaping, which increased plasma nicotine (+4.93±0.92 ng/mL, P<0.001; mean±SE) with no changes in exhaled carbon monoxide (-0.15±0.17 ppm; P=0.479), increased mean arterial pressure (11±1 mm Hg, P<0.001) and acutely decreased FMD from 5.79±0.58% to 4.39±0.46% (P<0.001). Ascorbic acid infusion, which increased plasma total antioxidant capacity 5-fold, increased FMD at baseline (5.98±0.66% versus 9.46±0.87%, P<0.001), and prevented the acute FMD impairment by e-hookah vaping (9.46±0.87% versus 8.74±0.84%, P=0.002). All parameters were unchanged during sham studies. Conclusions E-hookah vaping has adverse effects on vascular function, likely mediated by oxidative stress, which overtime could accelerate development and progression of cardiovascular disease. Registration URL: https://ClinicalTrials.gov. Unique identifier: NCT03690427.

Decline in endothelial function across the menopause transition in healthy women is related to decreased estradiol and increased oxidative stress

Endothelial function declines progressively across stages of the menopause transition; however, the mechanisms contributing to this decline are unknown. We hypothesized that differences in endothelial function among pre-, peri, and postmenopausal women are related to differences in estradiol and oxidative stress. Brachial artery flow-mediated dilation (FMD) was measured in 87 healthy women categorized by menopause stage (24 premenopausal, 17 early and 21 late perimenopausal, and 25 postmenopausal) before and after 3 days of ovarian hormone suppression (gonadotropin releasing hormone antagonist [GnRHant]) alone, and an additional 3 days of GnRHant with concurrent transdermal estradiol or placebo add-back treatment. In 82 women, FMD during acute vitamin C (antioxidant) infusion was measured before and after GnRHant + add-back. Before GnRHant, FMD was different among groups (p < 0.005; reduced across stages of menopause). Vitamin C increased FMD in late peri- and post- (p < 0.005) but not pre- or early perimenopausal women (p > 0.54). After GnRHant alone, FMD decreased in pre- and peri- (p < 0.01), but not postmenopausal women, and was restored to premenopausal levels by estradiol add-back in the pre- and perimenopausal groups. Vitamin C improved FMD in pre-, peri-, and postmenopausal women on GnRHant + placebo. There was no effect of vitamin C on FMD in women on GnRHant + estradiol. These observations support the concept that the decline in endothelial function across the menopause transition is related to the loss of ovarian estradiol. The decline in estradiol may alter redox balance, thereby increasing oxidative stress and impairing endothelial function.

Targeting mitochondrial fitness as a strategy for healthy vascular aging

Cardiovascular diseases (CVD) are the leading cause of death worldwide and aging is the primary risk factor for CVD. The development of vascular dysfunction, including endothelial dysfunction and stiffening of the large elastic arteries (i.e., the aorta and carotid arteries), contribute importantly to the age-related increase in CVD risk. Vascular aging is driven in large part by oxidative stress, which reduces bioavailability of nitric oxide and promotes alterations in the extracellular matrix. A key upstream driver of vascular oxidative stress is age-associated mitochondrial dysfunction. This review will focus on vascular mitochondria, mitochondrial dysregulation and mitochondrial reactive oxygen species (ROS) production and discuss current evidence for prevention and treatment of vascular aging via lifestyle and pharmacological strategies that improve mitochondrial health. We will also identify promising areas and important considerations ('research gaps') for future investigation.

Aging and Physiological Lessons from Master Athletes

Sedentary aging is often characterized by physical dysfunction and chronic degenerative diseases. In contrast, masters athletes demonstrate markedly greater physiological function and more favorable levels of risk factors for cardiovascular disease, osteoporosis, frailty, and cognitive dysfunction than their sedentary counterparts. In many cases, age-related deteriorations of physiological functions as well as elevations in risk factors that are typically observed in sedentary adults are substantially attenuated or even absent in masters athletes. Older masters athletes possess greater functional capacity at any given age than their sedentary peers. Impressive profiles of older athletes provide insight into what is possible in human aging and place aging back into the domain of "physiology" rather than under the jurisdiction of "clinical medicine." In addition, these exceptional aging athletes can serve as a role model for the promotion of physical activity at all ages. The study of masters athletes has provided useful insight into the positive example of successful aging. To further establish and propagate masters athletics as a role model for our aging society, future research and action are needed. © 2020 American Physiological Society. Compr Physiol 10:261-296, 2020.

Aerobic exercise training and vascular function with ageing in healthy men and women

Cardiovascular diseases (CVD) remain the leading cause of morbidity and mortality in both men and women in developed societies. Age is the greatest risk factor for CVD due largely to adverse changes to arteries that include stiffening of the large elastic arteries (aortic and carotid arteries) and endothelial dysfunction. Vascular ageing is driven by oxidative stress, which reduces nitric oxide (NO) bioavailability and stimulates changes in the extracellular matrix. In women, reductions in circulating oestrogens with menopause interact with ageing processes to induce vascular dysfunction. Regular aerobic exercise is the most evidence-based strategy for reducing CVD risk with ageing in both men and women. Much of this cardiovascular-protective effect of aerobic exercise is likely due to its vascular health-enhancing influence. Large elastic artery stiffening with advancing age is attenuated in healthy adults engaged in aerobic exercise training, and aerobic exercise interventions improve arterial stiffness in previously sedentary middle-aged and older men and postmenopausal women. Regular aerobic exercise also enhances endothelial function with ageing in men (by reducing oxidative stress and preserving NO bioavailability), but not consistently in oestrogen-deficient postmenopausal women. In postmenopausal women, treatment with oestradiol appears to restore the ability of aerobic exercise to improve NO-mediated endothelial function by reducing oxidative stress. Several research gaps exist in our understanding of potential sex differences in the vascular adaptations to regular aerobic exercise. More information is needed on the factors that are responsible for sex differences, including the role of circulating oestrogens in transducing the aerobic exercise training 'stimulus'.

Mechanisms of Vascular Aging

Aging of the vasculature plays a central role in morbidity and mortality of older people. To develop novel treatments for amelioration of unsuccessful vascular aging and prevention of age-related vascular pathologies, it is essential to understand the cellular and functional changes that occur in the vasculature during aging. In this review, the pathophysiological roles of fundamental cellular and molecular mechanisms of aging, including oxidative stress, mitochondrial dysfunction, impaired resistance to molecular stressors, chronic low-grade inflammation, genomic instability, cellular senescence, epigenetic alterations, loss of protein homeostasis, deregulated nutrient sensing, and stem cell dysfunction in the vascular system are considered in terms of their contribution to the pathogenesis of both microvascular and macrovascular diseases associated with old age. The importance of progeronic and antigeronic circulating factors in relation to development of vascular aging phenotypes are discussed. Finally, future directions and opportunities to develop novel interventions to prevent/delay age-related vascular pathologies by targeting fundamental cellular and molecular aging processes are presented.

Sex differences in mechanisms of arterial stiffness

Arterial stiffness progressively increases with aging and is an independent predictor of cardiovascular disease (CVD) risk. Evidence supports that there are sex differences in the time course of aging-related arterial stiffness and the associated CVD risk, which increases disproportionately in postmenopausal women. The association between arterial stiffness and mortality is almost twofold higher in women versus men. The differential clinical characteristics of the development of arterial stiffness between men and women indicate the involvement of sex-specific mechanisms. This review summarizes the current literature on sex differences in vascular stiffness induced by aging, obesity, hypertension, and sex-specific risk factors as well as the impact of hormonal status, diet, and exercise on vascular stiffness in males and females. An understanding of the mechanisms driving sex differences in vascular stiffness has the potential to identify novel sex-specific therapies to lessen CVD risk, the leading cause of death in males and females. LINKED ARTICLES: This article is part of a themed section on The Importance of Sex Differences in Pharmacology Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.21/issuetoc.

Decline of popliteal artery flow-mediated dilation with aging and possible involvement of asymmetric dimethylarginine in healthy men

Purpose

We examined the influences of age and gender on flow-mediated endothelial function and the involvement of the competitive inhibition of l-arginine in endothelial function.

Methods

We measured brachial and popliteal flow-mediated vasodilation (FMD) responses, nitrate/nitrite (NOx) concentrations, and plasma levels of asymmetric dimethylarginine (ADMA) in four healthy, nonsmoking groups: young men (mean 26 ± 2 years, n = 17), middle-aged men (mean 50 ± 3 years, n = 19), young women (mean 27 ± 2 years, n = 16), and middle-aged women (mean 51 ± 2 years, n = 18).

Results

In young men, we found no significant differences between brachial and popliteal artery FMDs (10.6 ± 1.5 vs 8.7 ± 1.6%, p = 0.06). However, the popliteal artery FMD was significantly lower than the brachial artery FMD in middle-aged men (11.4 ± 1.5 vs 6.4 ± 1.0%, p < 0.001). In women, we found no significant differences between brachial and popliteal artery FMDs in young and middle-aged individuals (young, p = 0.17; middle-aged, p = 0.08). Popliteal artery FMD correlated with plasma NOx and ADMA levels as well as with the NOx/ADMA ratio in men but not in women (r = 0.485, − 0.544, and 0.672, respectively).

Conclusion

We concluded that a decrease in flow-mediated endothelial function in arteries of the lower extremities was evident in healthy middle-aged men, but not in middle-aged women. The competitive inhibition of l-arginine may contribute to this decrease in men.

Exercise Improves Vascular Function, but does this Translate to the Brain?

The number of adults with Alzheimer’s disease (AD) or related dementia is expected to increase exponentially. Interventions aimed to reduce the risk and progression of AD and dementia are critical to the prevention and treatment of this devastating disease. Aging and cardiovascular disease risk factors are associated with reduced vascular function, which can have important clinical implications, including brain health. The age-associated increase in blood pressure and impairment in vascular function may be attenuated or even reversed through lifestyle behaviors. Greater volumes of habitual exercise and higher cardiorespiratory fitness are associated with beneficial effects on vascular health and cognition. Exercise and cardiorespiratory fitness may be most important during midlife, as physical activity and cardiorespiratory fitness during the middle-aged years are associated with future cognitive function. The extent to which exercise, and more specifically aerobic exercise, influences the cerebral circulation is not well established. In this review, we present our working hypothesis showing how cerebrovascular function may be a mediating factor underlying the association between exercise and cognition, as well as discuss recent studies evaluating the effect of exercise interventions on the cerebral circulation.

Healthy lifestyle-based approaches for successful vascular aging

This review summarizes a presentation given at the 2016 Gerontological Society of America Annual Meeting as part of the Vascular Aging Workshop. The development of age-related vascular dysfunction increases the risk of cardiovascular disease as well as other chronic age-associated disorders, including chronic kidney disease and Alzheimer's disease. Healthy lifestyle behaviors, most notably regular aerobic exercise and certain dietary patterns, are considered "first-line" strategies for the prevention and/or treatment of vascular dysfunction with aging. Despite the well-established benefits of these strategies, however, many older adults do not meet the recommended guidelines for exercise or consume a healthy diet. Therefore, it is important to establish alternative and/or complementary evidence-based approaches to prevent or reverse age-related vascular dysfunction. Time-efficient forms of exercise training, hormetic exposure to mild environmental stress, fasting "mimicking" dietary paradigms, and nutraceutical/pharmaceutical approaches to favorably modulate cellular and molecular pathways activated by exercise and healthy dietary patterns may hold promise as such alternative approaches. Determining the efficacy of these novel strategies is important to provide alternatives for adults with low adherence to conventional healthy lifestyle practices for healthy vascular aging.

Intersection between gonadal function and vascular aging in women

Vascular aging, characterized by endothelial dysfunction and large elastic arterial stiffening, is a major risk factor for age-associated cardiovascular disease (CVD). Although women have a lower prevalence of CVD until midlife, prevalence rates increase rapidly coincident with the menopausal transition to match those observed in men. The menopausal transition, or perimenopause, is a chaotic period that is associated with increased symptoms (e.g., hot flashes, depressed mood, anxiety, sleep disturbances) and CVD risk factors due to changes in the hormonal environment. Because these quality of life factors and CVD risk factors also change with aging, the arteries of women appear to endure a double insult. Our laboratory has been investigating how changes in gonadal function and hormone levels with the menopause transition impacts the vascular aging process in healthy women. Our work has shown that vascular endothelial function progressively declines, and large elastic arterial stiffness is greater across the stages of the menopausal transition. This acceleration in vascular aging may be due to the loss of vasodilatory, antioxidant, anti-inflammatory, and antiproliferative effects of estradiol on the vascular wall. This minireview discusses the impact of changes in gonadal function and hormones with the menopausal transition on vascular aging in women and areas for investigations to further our understanding of the intersection between gonadal function and vascular aging.

Mechanisms of Dysfunction in the Aging Vasculature and Role in Age-Related Disease

Advancing age promotes cardiovascular disease (CVD), the leading cause of death in the United States and many developed nations. Two major age-related arterial phenotypes, large elastic artery stiffening and endothelial dysfunction, are independent predictors of future CVD diagnosis and likely are responsible for the development of CVD in older adults. Not limited to traditional CVD, these age-related changes in the vasculature also contribute to other age-related diseases that influence mammalian health span and potential life span. This review explores mechanisms that influence age-related large elastic artery stiffening and endothelial dysfunction at the tissue level via inflammation and oxidative stress and at the cellular level via Klotho and energy-sensing pathways (AMPK [AMP-activated protein kinase], SIRT [sirtuins], and mTOR [mammalian target of rapamycin]). We also discuss how long-term calorie restriction-a health span- and life span-extending intervention-can prevent many of these age-related vascular phenotypes through the prevention of deleterious alterations in these mechanisms. Lastly, we discuss emerging novel mechanisms of vascular aging, including senescence and genomic instability within cells of the vasculature. As the population of older adults steadily expands, elucidating the cellular and molecular mechanisms of vascular dysfunction with age is critical to better direct appropriate and measured strategies that use pharmacological and lifestyle interventions to reduce risk of CVD within this population.

Vascular dysfunction across the stages of the menopausal transition is associated with menopausal symptoms and quality of life

OBJECTIVE

The menopausal transition is associated with somatic symptoms and increased rates of depression, which can impair quality of life (QOL) and increase cardiovascular disease (CVD) risk. This period is also associated with accelerated vascular aging (arterial stiffening and endothelial dysfunction), an antecedent to CVD. This secondary analysis sought to explore associations between depression, menopausal symptoms and QOL, and vascular aging across menopause stages.

METHODS

Arterial stiffness (carotid artery compliance), endothelial function (brachial artery flow-mediated dilation [FMD]), menopausal symptoms (Menopausal Symptom List [MSL]), depression (Center for Epidemiologic Studies Depression Scale [CES-D]), and QOL (Utian QOL Scale [UQOL]) were measured in 138 women (19-70 years) classified as premenopausal (n = 41, 34 ± 8 years; mean ± SD), early (n = 25, 49 ± 3 years), or late perimenopausal (n = 26, 50 ± 4 years), or early (n = 22, 55 ± 4 years) or late postmenopausal (n = 24, 61 ± 5 years). Differences across menopause stages were determined using one-way analysis of variance; associations between vascular measures and MSL, CES-D, and UQOL were tested using Pearson's correlation analyses.

RESULTS

Menopausal symptoms, depression, and QOL worsened across menopause stages, particularly in late perimenopausal women. Vasosomatic symptom frequency, and general somatic symptom frequency and severity were inversely correlated with carotid artery compliance and FMD (r = -0.27 to -0.18, all P < 0.05). Only correlations with general somatic symptoms were significant after adjusting for multiple comparisons. Total QOL was positively correlated with carotid artery compliance (r = 0.23, P = 0.01). CES-D scores were not correlated with carotid artery compliance or FMD (r = -0.08, -0.03, P = 0.35).

CONCLUSIONS

Vascular dysfunction across the stages of menopause was associated with greater frequency and severity of menopausal symptoms, and lower QOL, but not depression. Mechanisms underlying these associations (eg, inflammation, oxidative stress) should be explored.

Reversing age-associated arterial dysfunction: insight from preclinical models

Cardiovascular diseases (CVDs) remain the leading causes of death in the United States, and advancing age is a primary risk factor. Impaired endothelium-dependent dilation and increased stiffening of the arteries with aging are independent predictors of CVD. Increased tissue and systemic oxidative stress and inflammation underlie this age-associated arterial dysfunction. Calorie restriction (CR) is the most powerful intervention known to increase life span and improve age-related phenotypes, including arterial dysfunction. However, the translatability of long-term CR to clinical populations is limited, stimulating interest in the pursuit of pharmacological CR mimetics to reproduce the beneficial effects of CR. The energy-sensing pathways, mammalian target of rapamycin, AMPK, and sirtuin-1 have all been implicated in the beneficial effects of CR on longevity and/or physiological function and, as such, have emerged as potential targets for therapeutic intervention as CR mimetics. Although manipulation of each of these pathways has CR-like benefits on arterial function, the magnitude and/or mechanisms can be disparate from that of CR. Nevertheless, targeting these pathways in older individuals may provide some benefits against arterial dysfunction and CVD. The goal of this review is to provide a brief discussion of the mechanisms and pathways underlying age-associated dysfunction in large arteries, explain how these are impacted by CR, and to present the available evidence, suggesting that targets for energy-sensing pathways may act as vascular CR mimetics.

Chronic Supplementation With a Mitochondrial Antioxidant (MitoQ) Improves Vascular Function in Healthy Older Adults

Excess reactive oxygen species production by mitochondria is a key mechanism of age-related vascular dysfunction. Our laboratory has shown that supplementation with the mitochondrial-targeted antioxidant MitoQ improves vascular endothelial function by reducing mitochondrial reactive oxygen species and ameliorates arterial stiffening in old mice, but the effects in humans are unknown. Here, we sought to translate our preclinical findings to humans and determine the safety and efficacy of MitoQ. Twenty healthy older adults (60-79 years) with impaired endothelial function (brachial artery flow-mediated dilation <6%) underwent 6 weeks of oral supplementation with MitoQ (20 mg/d) or placebo in a randomized, placebo-controlled, double-blind, crossover design study. MitoQ was well tolerated, and plasma MitoQ was higher after the treatment versus placebo period (P<0.05). Brachial artery flow-mediated dilation was 42% higher after MitoQ versus placebo (P<0.05); the improvement was associated with amelioration of mitochondrial reactive oxygen species-related suppression of endothelial function (assessed as the increase in flow-mediated dilation with acute, supratherapeutic MitoQ [160 mg] administration; n=9; P<0.05). Aortic stiffness (carotid-femoral pulse wave velocity) was lower after MitoQ versus placebo (P<0.05) in participants with elevated baseline levels (carotid-femoral pulse wave velocity >7.60 m/s; n=11). Plasma oxidized LDL (low-density lipoprotein), a marker of oxidative stress, also was lower after MitoQ versus placebo (P<0.05). Participant characteristics, endothelium-independent dilation (sublingual nitroglycerin), and circulating markers of inflammation were not different (all P>0.1). These findings in humans extend earlier preclinical observations and suggest that MitoQ and other therapeutic strategies targeting mitochondrial reactive oxygen species may hold promise for treating age-related vascular dysfunction.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02597023.

Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults

Nicotinamide adenine dinucleotide (NAD+) has emerged as a critical co-substrate for enzymes involved in the beneficial effects of regular calorie restriction on healthspan. As such, the use of NAD+ precursors to augment NAD+ bioavailability has been proposed as a strategy for improving cardiovascular and other physiological functions with aging in humans. Here we provide the evidence in a 2 × 6-week randomized, double-blind, placebo-controlled, crossover clinical trial that chronic supplementation with the NAD+ precursor vitamin, nicotinamide riboside (NR), is well tolerated and effectively stimulates NAD+ metabolism in healthy middle-aged and older adults. Our results also provide initial insight into the effects of chronic NR supplementation on physiological function in humans, and suggest that, in particular, future clinical trials should further assess the potential benefits of NR for reducing blood pressure and arterial stiffness in this group.

Hormone phase influences sympathetic responses to high levels of lower body negative pressure in young healthy women

We tested the hypothesis that sympathetic responses to baroreceptor unloading may be affected by circulating sex hormones. During lower body negative pressure at -30, -60, and -80 mmHg, muscle sympathetic nerve activity (MSNA), heart rate, and blood pressure were recorded in women who were taking (n = 8) or not taking (n = 9) hormonal contraceptives. All women were tested twice, once during the low-hormone phase (i.e., the early follicular phase of the menstrual cycle and the placebo phase of hormonal contraceptive use), and again during the high-hormone phase (i.e., the midluteal phase of the menstrual cycle and active phase of contraceptive use). During baroreceptor unloading, the reductions in stroke volume and resultant increases in MSNA and total peripheral resistance were greater in high-hormone than low-hormone phases in both groups. When normalized to the fall in stroke volume, increases in MSNA were no longer different between hormone phases. While stroke volume and sympathetic responses were similar between women taking and not taking hormonal contraceptives, mean arterial pressure was maintained during baroreceptor unloading in women not taking hormonal contraceptives but not in women using hormonal contraceptives. These data suggest that differences in sympathetic activation between hormone phases, as elicited by lower body negative pressure, are the result of hormonally mediated changes in the hemodynamic consequences of negative pressure, rather than centrally driven alterations to sympathetic regulation.

Effect of Strength Training on Oxidative Stress and the Correlation of the Same with Forearm Vasodilatation and Blood Pressure of Hypertensive Elderly Women: A Randomized Clinical Trial

The aim of the study was to evaluate the effect of strength training on oxidative stress and the correlation of the same with forearm vasodilatation and mean blood pressure of hypertensive elderly women, at rest (basal) and during a static handgrip exercise. Insufficiently active hypertensive elderly women (N = 25; mean age = 66.1 years) were randomized into a 10 week strength training group (n = 13) or control (n = 12) group. Plasma malondialdehyde (MDA), total antioxidant capacity (TAC), plasma nitrite (NO2-), forearm blood flow (FBF), mean blood pressure (MBP) and vascular conductance ([FBF / MBP] x 100) were evaluated before and after the completion of the interventions. The strength training group increased the TAC (pre: Median = 39.0; Interquartile range = 34.0-41.5% vs post: Median = 44.0; Interquartile range = 38.0-51.5%; p = 0.006) and reduced the MDA (pre: 4.94 ± 1.10 μM vs post: 3.90 ± 1.35 μM; p = 0.025; CI-95%: -1.92 --0.16 μM). The strength training group increased basal vascular conductance (VC) (pre: 3.56 ±0.88 units vs post: 5.21 ±1.28 units; p = 0.001; CI-95%: 0.93-2.38 units) and decreased basal MBP (pre: 93.1 ±6.3 mmHg vs post: 88.9 ±5.4 mmHg; p = 0.035; CI-95%: -8.0 --0.4 mmHg). Such changes were also observed during static handgrip exercise. A moderate correlation was observed between changes in basal VC and MBP with changes in NO2- (ΔVC → r = -0.56, p = 0.047; ΔMBP → r = -0.41, p = 0.168) and MDA (ΔVC → r = 0.64, p = 0.019; ΔMBP → r = 0.31, p = 0.305). The strength training program reduced the oxidative stress of the hypertensive elderly women and this reduction was moderately correlated with their cardiovascular benefits.

TRIAL REGISTRATION

ensaiosclinicos.gov.br RBR-48c29w.

Acute ascorbic acid infusion increases left ventricular diastolic function in postmenopausal women

OBJECTIVES

We tested the hypothesis that oxidative stress contributes to reductions in left ventricular diastolic (LV) function in estrogen-deficient postmenopausal women, related in part to reduced nitric oxide (NO) bioavailability.

STUDY DESIGN

LV diastolic function - recorded using transthoracic echocardiography and determined as the peak early (E) to late (A) mitral inflow velocity ratio and the E to peak early (e') mitral annular velocity ratio - and brachial artery flow mediated dilation (FMD), a biomarker of NO bioavailability, were measured during acute systemic infusions of saline (control) and ascorbic acid (experimental model to decrease oxidative stress) in healthy premenopausal women (N=14, 18-40 years) and postmenopausal women (N=23, 45-75 years).

RESULTS

The E/A ratio was lower (1.16[1.06-1.33] vs 1.65[1.5-2.3]; median[interquartile range]) and the E/e' ratio was elevated (8.8[7.6-9.9] vs. 6.6[5.5-7.3]) in postmenopausal compared with premenopausal women, indicating reduced LV diastolic function. E/A and E/e' were correlated with FMD (r=0.54 and r=-0.59, respectively, both P<0.01). Ascorbic acid infusion improved both FMD (5.4±2.0% to 7.8±2.6%) and E/e' (to 8.1[7.2-9.7], P=0.01) in postmenopausal women but not in premenopausal women. Ascorbic acid did not change E/A in either group.

CONCLUSION

The current study provides evidence that oxidative stress contributes to reduced LV diastolic function in estrogen-deficient postmenopausal women, possibly by reducing the availability of NO.

Oral trehalose supplementation improves resistance artery endothelial function in healthy middle-aged and older adults

We hypothesized that supplementation with trehalose, a disaccharide that reverses arterial aging in mice, would improve vascular function in middle-aged and older (MA/O) men and women. Thirty-two healthy adults aged 50-77 years consumed 100 g/day of trehalose (n=15) or maltose (n=17, isocaloric control) for 12 weeks (randomized, double-blind). In subjects with Δbody mass less than 2.3kg (5 lb.), resistance artery endothelial function, assessed by forearm blood flow to brachial artery infusion of acetylcholine (FBFACh), increased ~30% with trehalose (13.3±1.0 vs. 10.5±1.1 AUC, P=0.02), but not maltose (P=0.40). This improvement in FBFACh was abolished when endothelial nitric oxide (NO) production was inhibited. Endothelium-independent dilation, assessed by FBF to sodium nitroprusside (FBFSNP), also increased ~30% with trehalose (155±13 vs. 116±12 AUC, P=0.03) but not maltose (P=0.92). Changes in FBFACh and FBFSNP with trehalose were not significant when subjects with Δbody mass ≥ 2.3kg were included. Trehalose supplementation had no effect on conduit artery endothelial function, large elastic artery stiffness or circulating markers of oxidative stress or inflammation (all P>0.1) independent of changes in body weight. Our findings demonstrate that oral trehalose improves resistance artery (microvascular) function, a major risk factor for cardiovascular diseases, in MA/O adults, possibly through increasing NO bioavailability and smooth muscle sensitivity to NO.

Effect of Simvastatin on Arterial Stiffness in Patients with Statin Myalgia

Statins reduce arterial stiffness but are also associated with mild muscle complaints. It is unclear whether individuals with muscle symptoms experience the same vascular benefit or whether statins affect striated and smooth muscle cells differently. We examined the effect of simvastatin treatment on arterial stiffness in patients who did versus those who did not exhibit muscle symptoms. Patients with a history of statin-related muscle complaints (n = 115) completed an 8 wk randomized, double-blind, cross-over trial of daily simvastatin 20 mg and placebo. Serum lipids and pulse wave velocity (PWV) were assessed before and after each treatment. Muscle symptoms with daily simvastatin treatment were reported by 38 patients (33%). Compared to baseline, central PWV decreased (P = 0.01) following simvastatin treatment but not placebo (drug ∗ time interaction: P = 0.047). Changes in central PWV with simvastatin treatment were not influenced by myalgia status or time on simvastatin (P ≥ 0.15). Change in central PWV after simvastatin treatment was inversely correlated with age (r = -0.207, P = 0.030), suggesting that advancing age is associated with enhanced statin-mediated arterial destiffening. In patients with a history of statin-related muscle complaints, the development of myalgia with short-term simvastatin treatment did not attenuate the improvement in arterial stiffness.

Oxidative stress contributes to large elastic arterial stiffening across the stages of the menopausal transition

OBJECTIVE

It is unclear how changes in ovarian hormones during the menopausal transition contribute to age-associated arterial stiffening. We sought to evaluate differences in arterial stiffness and the role of oxidative stress across the stages of the menopausal transition in healthy women.

METHODS

Arterial stiffness (carotid artery compliance and ultrasound) was measured during immediate infusions of saline (control) and ascorbic acid (experimental model to immediately decrease oxidative stress) in 97 healthy women (22-70 y) classified as premenopausal (n = 24; mean [SD] age, 33 [7] y), early perimenopausal (n = 21; 49 [3] y) or late perimenopausal (n = 21; 50 [4] y), or postmenopausal (n = 31; 57 [5] y).

RESULTS

Basal carotid artery compliance was different among the groups (P < 0.001). Mean [SD] compliance was highest in premenopausal women (1.31 [0.25] mm/mm Hg × 10), with progressive decrements in perimenopausal (early perimenopausal, 0.98 [0.31] mm/mm Hg × 10; late perimenopausal, 0.90 [0.25] mm/mm Hg × 10) and postmenopausal (0.75 [0.24] mm/mm Hg × 10) women. Ascorbic acid infusion improved compliance in late perimenopausal (15% [18%] increase, P = 0.001) and postmenopausal (17% [26%] increase, P = 0.002) women but not in early perimenopausal or premenopausal women.

CONCLUSIONS

Arterial stiffening worsens across the stages of the menopausal transition in healthy women. This seems to be mediated, in part, by oxidative stress, particularly during the late perimenopausal and postmenopausal periods. It remains uncertain whether this is specifically caused by loss of ovarian function or aging.

Sex differences in ventricular-vascular coupling following endurance training

Introduction

Ventricular and vascular coupling is defined as the ratio of arterial elastance (Ea) to ventricular elastance (Elv) and describes the interaction between the heart and arterial system. There are sex differences in both arterial and ventricular function in response to both acute exercise and aerobic exercise training.

Purpose

To examine the effects of aerobic exercise training on elastances and the coupling ratio in young adult men and women. We hypothesized a reduction in the coupling ratio in both sexes due to a decrease in Ea that would be more pronounced in men and an increase in Elv that would be larger in women.

Methods

Fifty-three healthy, young adults completed the study. Central pulse wave velocity and heart volumes were measured before and after an 8-week aerobic training intervention. Elastances were calculated as Ea = end-systolic pressure/stroke volume and Elv = end-systolic pressure/end-systolic volume and indexed to body surface area.

Results

After the intervention, women augmented indexed and un-indexed Elv from 2.09 ± 0.61 to 2.52 ± 0.80 mmHg/ml, p < 0.05, and reduced the coupling ratio from 0.72 ± 18 to 0.62 ± 15, p < 0.05, while men maintained their pre-training ratio (from 0.66 ± 0.20 to 0.74 ± 0.21, p > 0.05). Women also reduced end-systolic pressure (from 91 ± 10 to 87 ± 10 mmHg), and both groups reduced central pulse wave velocity (from 6.0 ± 1.0 to 5.6 ± 0.6 m/s, p < 0.05).

Conclusion

We conclude that after 8 weeks of aerobic training, only women reduced their coupling ratio due to an increase in Elv. This suggests that aerobic exercise training elicits sex-dependent changes in the coupling ratio in young, healthy individuals.

Reactive oxygen species, vascular Noxs, and hypertension: focus on translational and clinical research

SIGNIFICANCE

Reactive oxygen species (ROS) are signaling molecules that are important in physiological processes, including host defense, aging, and cellular homeostasis. Increased ROS bioavailability and altered redox signaling (oxidative stress) have been implicated in the onset and/or progression of chronic diseases, including hypertension.

RECENT ADVANCES

Although oxidative stress may not be the only cause of hypertension, it amplifies blood pressure elevation in the presence of other pro-hypertensive factors, such as salt loading, activation of the renin-angiotensin-aldosterone system, and sympathetic hyperactivity, at least in experimental models. A major source for ROS in the cardiovascular-renal system is a family of nicotinamide adenine dinucleotide phosphate oxidases (Noxs), including the prototypic Nox2-based Nox, and Nox family members: Nox1, Nox4, and Nox5.

CRITICAL ISSUES

Although extensive experimental data support a role for increased ROS levels and altered redox signaling in the pathogenesis of hypertension, the role in clinical hypertension is unclear, as a direct causative role of ROS in blood pressure elevation has yet to be demonstrated in humans. Nevertheless, what is becoming increasingly evident is that abnormal ROS regulation and aberrant signaling through redox-sensitive pathways are important in the pathophysiological processes which is associated with vascular injury and target-organ damage in hypertension.

FUTURE DIRECTIONS

There is a paucity of clinical information related to the mechanisms of oxidative stress and blood pressure elevation, and a few assays accurately measure ROS directly in patients. Such further ROS research is needed in humans and in the development of adequately validated analytical methods to accurately assess oxidative stress in the clinic.

Oxidative stress induces gastric submucosal arteriolar dysfunction in the elderly

AIM: To evaluate human gastric submucosal vascular dysfunction and its mechanism during the aging process.

METHODS: Twenty male patients undergoing subtotal gastrectomy were enrolled in this study. Young and elderly patient groups aged 25-40 years and 60-85 years, respectively, were included. Inclusion criteria were: no clinical evidence of cardiovascular, renal or diabetic diseases. Conventional clinical examinations were carried out. After surgery, gastric submucosal arteries were immediately dissected free of fat and connective tissue. Vascular responses to acetylcholine (ACh) and sodium nitroprusside (SNP) were measured by isolated vascular perfusion. Morphological changes in the gastric mucosal vessels were observed by hematoxylin and eosin (HE) staining and Verhoeff van Gieson (EVG) staining. The expression of xanthine oxidase (XO) and manganese-superoxide dismutase (Mn-SOD) was assessed by Western blotting analysis. The malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) content and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined according to commercial kits.

RESULTS: The overall structure of vessel walls was shown by HE and EVG staining, respectively. Disruption of the internal elastic lamina or neointimal layers was not observed in vessels from young or elderly patients; however, cell layer number in the vessel wall increased significantly in the elderly group. Compared with submucosal arteries in young patients, the amount of vascular collagen fibers, lumen diameter and media cross-sectional area were significantly increased in elderly patients. Ach- and SNP-induced vasodilatation in elderly arterioles was significantly decreased compared with that of gastric submucosal arterioles from young patients. Compared with the young group, the expression of XO and the contents of MDA and H₂O₂ in gastric submucosal arterioles were increased in the elderly group. In addition, the expression of Mn-SOD and the activities of SOD and GSH-Px in the elderly group decreased significantly compared with those in the young group.

CONCLUSION: Gastric vascular dysfunction and senescence may be associated with increased oxidative stress and decreased antioxidative defense in the aging process.

Oral sapropterin acutely augments reflex vasodilation in aged human skin through nitric oxide-dependent mechanisms

Functional constitutive nitric oxide synthase (NOS) and its cofactor tetrahydrobiopterin (BH4) are required for full reflex cutaneous vasodilation and are attenuated in primary aging. Acute, locally administered BH4 increases reflex vasodilation through NO-dependent mechanisms in aged skin. We hypothesized that oral sapropterin (Kuvan, shelf-stable pharmaceutical formulation of BH4) would augment reflex vasodilation in aged human skin during hyperthermia. Nine healthy human subjects (76 ± 1 yr) ingested sapropterin (10 mg/kg) or placebo in a randomized double-blind crossover design. Venous blood samples were collected prior to, and 3 h following, ingestion of sapropterin for measurement of plasma BH4. Three intradermal microdialysis fibers were placed in the forearm skin for local delivery of 1) lactated Ringer's solution, 2) 10 mM BH4, and 3) 20 mM N(G)-nitro-l-arginine methyl ester (l-NAME) to inhibit NOS. Red cell flux was measured at each site by laser-Doppler flowmetry (LDF) as reflex vasodilation was induced using a water-perfused suit. At 1°C rise in oral temperature, mean body temperature was clamped and 20 mM l-NAME was perfused at each site. Cutaneous vascular conductance was calculated (CVC = LDF/MAP) and expressed as a percentage of maximum (%CVCmax 28 mM sodium nitroprusside and local heat 43°C). Plasma concentrations of BH4 were significantly elevated 3 h after ingestion of sapropterin (0 h: 19.1 ± 2 pmol/ml vs. 3 h: 43.8 ± 3 pmol/ml; P < 0.001). Sapropterin increased NO-dependent vasodilation at control site (placebo: 14 ± 1 %CVCmax vs. sapropterin: 25 ± 4 %CVCmax; P = 0.004). Local BH4 administration increased NO-dependent vasodilation compared with control in placebo trials only (control: 14 ± 1 %CVCmax vs. BH4-treated: 24 ± 3 %CVCmax; P = 0.02). These data suggest oral sapropterin increases bioavailable BH4 in aged skin microvasculature sufficiently to increase NO synthesis through NOS and that sapropterin may be a viable intervention to increase skin blood flow during hyperthermia in healthy aged humans.

Tumor necrosis factor-α inhibition improves endothelial function and decreases arterial stiffness in estrogen-deficient postmenopausal women

OBJECTIVE

Tumor necrosis factor (TNF)-α, a pleiotropic pro-inflammatory cytokine involved in a variety of biological processes including oxidative stress, has been associated with vascular dysfunction in aged and ovariectomized animals. We determined whether acute inhibition of TNF-α improves vascular endothelial function and decreases arterial stiffness in estrogen-deficient postmenopausal women.

METHODS

Arterial stiffness (carotid artery compliance) and endothelial function (brachial artery flow-mediated dilation [FMD]) were measured in postmenopausal women (n = 23; 57 ± 1 years, mean ± SE) before and following randomization to two days of either transdermal estradiol (0.05 mg/d, N = 12) or placebo (N = 11) alone and following a single subcutaneous injection of the TNF-α inhibitor, etanercept (25 mg), and in premenopausal (n = 9; 33 ± 2 years) before and following etanercept.

RESULTS AND CONCLUSIONS

Baseline carotid artery compliance and brachial artery FMD were lower in postmenopausal than premenopausal women (P < 0.0001). In postmenopausal women, carotid artery compliance (n = 12; 0.59 ± 0.05-0.78 ± 0.06 mm(2)/mmHg × 10(-1), P < 0.001) and FMD (4.1 ± 0.6-6.0 ± 0.7%, P = 0.02) increased in response to estradiol but not placebo (n = 11). Carotid artery compliance (0.71 ± 0.06-0.81 ± 0.06 mm(2)/mmHg × 10(-1), P = 0.02) and FMD (5.2 ± 0.7-7.5 ± 0.9%, P = 0.003) increased with etanercept in the placebo group but had no effect in postmenopausal randomized to estradiol or premenopausal women. These results suggest that TNF-α contributes to impaired endothelial-dependent vasodilation and arterial stiffening in estrogen-deficient postmenopausal women.

Role of mineralocorticoid receptors in arterial stiffness in human aging

Arterial stiffness, an independent predictor of cardiovascular disease, is increased in aging, but the underlying mechanisms are not completely understood. Mineralocorticoid receptors (MR) may contribute to oxidative stress and arterial stiffness in healthy older adults. To test the hypothesis that short-term MR blockade may reduce oxidative stress and improve arterial stiffness, we conducted a randomized, double blind, crossover study using the selective MR blocker Eplerenone or placebo in 23 older adults (age, 64±1 years; mean±SE) free from overt cardiovascular and other clinical disease (e.g, diabetes, renal and liver disease). In response to MR blockade, brachial and carotid blood pressure decreased (P≤0.01). However, MR blockade had no effect on oxidative stress (oxidized LDL, 61.2±6.8 vs. 62.4±7.4 U/L, P=0.9; placebo vs. Eplerenone) and arterial stiffness (aortic pulse wave velocity (PWV), 9.17±1.19 vs. 8.92±1.19 m/s, P=0.5; leg PWV, 13.45±0.45 vs. 12.81±0.47 m/s, P=0.3; arm PWV, 11.43±0.62 vs. 11.73±0.68 m/s, P=0.7; carotid artery compliance, 0.150±0.013 vs. 0.149±0.014 mm(2)/mmHg, P=0.8; distensibility, 23.1±1.8 vs. 23.3±1.7 10(-3)/kPa, P=0.8; β stiffness index, 3.5±0.3 vs. 3.6±0.3, P=0.6; and augmentation index, 16.0±2.2 vs. 15.6±2.8%, P=0.8). These results provide the first evidence that MR do not appear to contribute to oxidative stress in human aging and that short-term MR blockade does not result in reduced oxidative stress and improved arterial stiffness.

The framingham risk score, diet, and inflammatory markers in Korean men with metabolic syndrome

The Framingham risk score (FRS) has been used to assess the risk of a cardiovascular event and to identify patients for risk factor modifications. Therefore, the purpose of this study was to evaluate the relationship of the FRS with dietary intake and inflammatory biomarkers. We conducted a cross-sectional study of 180 men (49.2 ± 10.2 years) with MS. Serum levels of high sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6), and adiponectin were examined. Participants were asked to complete the food frequency questionnaire (FFQ) using the previous 1 year as a reference point. The absolute cardiovascular disease (CVD) risk percentage over 10 years was calculated to estimate the FRS, which was classified as low risk (< 10%), intermediate risk (10-20%), and high risk (> 20%). Mean intake of polyunsaturated fatty acids was lower in subjects who had > 20% FRS than in subjects who had < 10% FRS (3.7 ± 1.9 g/day vs. 4.7 ± 1.9 g/day; P < 0.05). Significant differences in the Index of Nutritional Quality of protein, phosphorus, iron, vitamin A, vitamin B₁, niacin, vitamin B₆, and vitamin C were observed between the > 20% FRS group and the < 10% FRS group (P < 0.05). IL-6 concentrations were significantly lower in subjects with a < 10% FRS than in subjects who were 10-20% FRS or > 20% FRS (0.91 ± 0.26 vs. 1.48 ± 033 vs. 2.72 ± 0.57 pg/mL, respectively; P < 0.05). IL-6 and dietary intake of polyunsaturated fatty acids together explained 6.6% of the variation in FRS levels in a stepwise multiple regression model. Our results provide some evidence that dietary intake in the higher CVD risk group was inferior to that in the lower risk group and that dietary fat intake and IL-6 were associated with FRS and MS in Korean men.

Age related cardiovascular dysfunction and effects of physical activity

The aim of the present article is to review the principal pathogenetic pathways of age-related cardiovascular changes and the positive effects of physical activity on these changes as well as on related cardiovascular dysfunction. The ageing mechanisms reviewed have been grouped into reduced tolerance of oxidative stress, loss of cardiac stem cells, cardiovascular remodeling and impairment of neurovegetative control. New pathogenetic conditions and their tests are described (sirtuines, telomere length, heart rate variability). Age related cardiovascular changes predispose the individual to arterial hypertension, heart failure and arrythmia. A broad spectrum of tests are available to indentify and monitor the emerging cardiovascular dysfunction. Physical activity influences all age related cardiovascular mechanisms, improves cardiovascular function and even, at moderate intensity can reduce mortality and heart attack risk. It is likely that the translation of laboratory studies to humans will improve understanding and stimulate the use of physical activity to benefit cardiovascular patients.

Tetrahydrobiopterin improves endothelial function and decreases arterial stiffness in estrogen-deficient postmenopausal women

The mechanisms mediating arterial stiffening with aging and menopause are not completely understood. We determined whether administration of tetrahydrobiopterin (BH(4)), a critical cofactor for endothelial nitric oxide synthase to produce nitric oxide, would increase vascular endothelial-dependent vasodilatory tone and decrease arterial stiffness in estrogen-deficient postmenopausal women. Additionally, we examined whether the beneficial effects of estrogen on vascular function were possibly related to BH(4). Arterial stiffness (carotid artery compliance) and endothelial-dependent vasodilation [brachial artery flow-mediated dilation (FMD)] were measured in postmenopausal (n = 24; 57 ± 1 yr, mean ± SE) and eumenorrheic premenopausal (n = 9; 33 ± 2 yr) women before and 3 h after the oral administration of BH(4). Subsequently, in postmenopausal women, vascular testing (before and after BH(4)) was repeated following randomization to either 2 days of transdermal estradiol or placebo. Baseline carotid artery compliance and brachial artery FMD were lower in postmenopausal than in premenopausal women (P < 0.0001). BH(4) administration increased carotid artery compliance (0.61 ± 0.05 to 0.73 ± 0.04 mm(2)·mmHg(-1)·10(-1) vs. baseline, P < 0.0001) and brachial artery FMD (P < 0.001) in postmenopausal women but had no effect in premenopausal women (P = 0.62). Carotid artery compliance (0.59 ± 0.05 to 0.78 ± 0.06 mm(2)·mmHg(-1)·10(-1), P < 0.001) and FMD increased in postmenopausal women in response to estradiol (P = 0.02) but were not further improved with the coadministration of BH(4), possibly because estrogen increased BH(4) bioavailability. Carotid artery compliance and FMD increased with BH(4) in the placebo group (P = 0.02). Although speculative, these results suggest that reduced vascular BH(4) may be an important contributor to arterial stiffening in estrogen-deficient postmenopausal women, related in part to reduced endothelial-dependent vasodilatory tone.

SIRT-1 and vascular endothelial dysfunction with ageing in mice and humans

We tested the hypothesis that reductions in the cellular deacetylase, sirtuin-1 (SIRT-1), contribute to vascular endothelial dysfunction with ageing via modulation of endothelial nitric oxide synthase (eNOS) acetylation/activation-associated nitric oxide (NO) production. In older (30 months, n = 14) vs. young (5-7 months, n = 16) B6D2F1 mice, aortic protein expression of SIRT-1 and eNOS phosphorylated at serine 1177 were lower (both P < 0.05), and acetylated eNOS was 6-fold higher (P < 0.05), whereas total eNOS did not differ (P = 0.65). Acetylcholine (ACh)-induced peak endothelium-dependent dilatation (EDD) was lower in isolated femoral arteries with ageing (P < 0.001). Incubation with sirtinol, a SIRT-1 inhibitor, reduced EDD in both young and older mice, abolishing age-related differences, whereas co-administration with l-NAME, an eNOS inhibitor, further reduced EDD similarly in both groups. Endothelium-independent dilatation to sodium nitroprusside (EID), was not altered by age or sirtinol treatment. In older (64 ± 1 years, n = 22) vs. young (25 ± 1 years, n = 16) healthy humans, ACh-induced forearm EDD was impaired (P = 0.01) and SIRT-1 protein expression was 37% lower in endothelial cells obtained from the brachial artery (P < 0.05), whereas EID did not differ. In the overall group, EDD was positively related to endothelial cell SIRT-1 protein expression (r = 0.44, P < 0.01). Reductions in SIRT-1 may play an important role in vascular endothelial dysfunction with ageing. SIRT-1 may be a key therapeutic target to treat arterial ageing.