Race and sex differences in cardiovascular autonomic regulation

Neural Circuits Underlying Reciprocal Cardiometabolic Crosstalk: 2023 Arthur C. Corcoran Memorial Lecture

The interplay of various body systems, encompassing those that govern cardiovascular and metabolic functions, has evolved alongside the development of multicellular organisms. This evolutionary process is essential for the coordination and maintenance of homeostasis and overall health by facilitating the adaptation of the organism to internal and external cues. Disruption of these complex interactions contributes to the development and progression of pathologies that involve multiple organs. Obesity-associated cardiovascular risks, such as hypertension, highlight the significant influence that metabolic processes exert on the cardiovascular system. This cardiometabolic communication is reciprocal, as indicated by substantial evidence pointing to the ability of the cardiovascular system to affect metabolic processes, with pathophysiological implications in disease conditions. In this review, I outline the bidirectional nature of the cardiometabolic interaction, with special emphasis on the impact that metabolic organs have on the cardiovascular system. I also discuss the contribution of the neural circuits and autonomic nervous system in mediating the crosstalk between cardiovascular and metabolic functions in health and disease, along with the molecular mechanisms involved.

Sex differences in sympathetic activity and pulse wave velocity in adults with chronic kidney disease

Chronic kidney disease (CKD) is characterized by sympathetic nervous system (SNS) overactivity that contributes to increased vascular stiffness and cardiovascular risk. Although it is well established that SNS activity and vascular stiffness are substantially elevated in CKD, whether sex differences in autonomic and vascular function exist in CKD remains unknown. We tested the hypothesis that compared with females, males with CKD have higher baseline sympathetic activity that is related to increased arterial stiffness. One hundred twenty-nine participants (96 males and 33 females) with CKD stages III and IV were recruited and enrolled. During two separate study visits, vascular stiffness was assessed by measuring carotid-to-femoral pulse wave velocity (cfPWV), and resting muscle sympathetic nerve activity (MSNA) was measured by microneurography. Males with CKD had higher resting MSNA compared with females with CKD (68 ± 16 vs. 55 ± 14 bursts/100 heart beats, P = 0.005), whereas there was no difference in cfPWV between the groups (P = 0.248). Resting MSNA was not associated with cfPWV in both males and females. In conclusion, males with CKD have higher resting sympathetic activity compared with females with CKD. However, there was no difference in vascular stiffness between the sexes. There was no correlation between resting MSNA and cfPWV, suggesting that non-neural mechanisms may play a greater role in the progression of vascular stiffness in CKD, particularly in females.NEW & NOTEWORTHY Males with chronic kidney disease (CKD) have higher resting muscle sympathetic nerve activity (MSNA) compared with females. There was no correlation between MSNA and carotid-to-femoral pulse wave velocity (cfPWV), suggesting that non-neural mechanisms may play a greater role in the progression of vascular stiffness in CKD. Sex differences in SNS activity may play a mechanistic role in observations from epidemiological studies suggesting greater cardiovascular risk in males compared with females with CKD.

Utility of nailfold capillary assessment for predicting pustulotic arthro-osteitis in palmoplantar pustulosis based on a prospective cohort study

BACKGROUND

Pustulotic arthro-osteitis (PAO) is 1 of the most serious comorbidities associated with palmoplantar pustulosis (PPP). Risk factors of PAO development are not well-known.

OBJECTIVE

To evaluate the clinical significance of nailfold capillary (NFC) changes in patients with PPP.

METHODS

We conducted a prospective cohort study in a population of 102 PPP patients. Correlations of NFC abnormalities, including nailfold bleeding and enlarged capillaries, with the prevalence of PAO, the incidence of new PAO, and serum levels of cytokines were analyzed.

RESULTS

Detailed examination revealed that of 102 PPP patients, 52 without PAO and 50 with PAO. Both nailfold bleeding and enlarged capillaries were significantly more frequent in patients with PAO (50.0% vs 92.0%, P < .0001; 50.0% vs 94.0%, P < .0001). In addition, PPP patients without PAO were prospectively observed before they developed PAO (mean 28 months [1-52 months]). Multivariate analysis suggested that these NFC abnormalities were predictors of PAO development (hazard ratio 3.37, 95% confidence interval 1.13-10.07; 3.37, 1.13-10.07) and guselkumab prevent PAO development (0.093, 0.012-0.76). The degree of NFC abnormalities correlated with the severity of PAO and serum cytokine levels.

LIMITATIONS

All participants were Japanese.

CONCLUSION

NFC abnormalities could be predictors of PAO in PPP patients, and their degree indicators of disease severity.

Utility of nailfold capillary assessment for predicting psoriatic arthritis based on a prospective observational cohort study

OBJECTIVES

PsA is one of the most serious comorbidities associated with psoriasis. While the early intervention in PsA is demanded, risk factors of PsA development are not well-known. This is the first prospective study to evaluate the clinical significance of nailfold capillary (NFC) changes in patients with psoriasis.

METHODS

We conducted a prospective cohort study in a population of 449 psoriasis patients who had not been treated with systemic therapy or topical finger therapy. NFCs were observed by dermoscopy and capillaroscopy, and the correlation of NFC abnormalities, including nailfold bleeding (NFB) and enlarged capillaries, with the prevalence of PsA, incidence of new PsA, and serum levels of TNF-a, IL-17A and IL-23 were analysed.

RESULTS

Detailed examination at the time of inclusion revealed that of 449 patients, 236 had Psoriasis vulgaris (PsV) and 213 had PsA. Both NFB and enlarged capillaries were significantly more frequent in patients with PsA (34.7% vs 84.5%, P < 0.0001; 25.4% vs 100%, P < 0.0001). In addition, PsV patients were prospectively observed before they developed PsA (mean 21 months, 95% CI 2, 77 months). Multivariate analysis suggested that the appearance of NFB and enlarged capillaries was a predictor of PsA development (HR 2.75, 95% CI 1.38, 5.47 and HR 4.49, 95% CI 2.25, 8.96, respectively). The degree of NFC abnormalities also correlated with the severity of PsA and serum cytokine levels.

CONCLUSIONS

NFC abnormalities were suggested to be a predictor of PsA in psoriasis patients, and at the same time, its degree could be an indicator of disease severity.

Biological effects of negative air ions on human health and integrated multiomics to identify biomarkers: a literature review

Environmental pollution seriously affects human health. The concentration of negative air ions (NAIs), which were discovered at the end of the nineteenth century, is one of the factors used to evaluate air quality. Additionally, NAIs have been widely considered markers by scholars due to their unique biological function. The aim of this study was to summarize existing research and propose future research on the generation and temporal and spatial dynamic patterns of NAIs concentrations as well as the relationship between NAIs and human health. We identified 187 studies (published January 2013-January 2023) that met our inclusion criteria. Fourteen English studies evaluated the effects of NAIs on depression, the cardiovascular system, the respiratory system, reproduction and development, cognition, and sports muscle injury. Only two studies reported the associations of NAIs exposure with metabolic omics. NAIs concentrations vary temporally with solar radiation, air temperature, and relative humidity, while the temporal dynamic patterns of NAIs are affected by season, time, meteorological factors, air quality index, geographical location, forest vegetation, and other factors. Researchers have shown that exposure to NAIs may benefit our health by changing amino acid metabolism, which mainly manifests as increased anti-inflammation and reduced inflammation and antioxidation. Furthermore, exposure to NAIs promotes energy production, affects the expression of c-fos, and regulates 5-HT levels. There has been considerable interest in the potential effects of NAIs on human health and well-being, but the conclusions have been inconsistent and the mechanisms remain unclear. The use of omics to elucidate the biological mechanism of NAIs is relatively new and has some advantages.

Racial Differences in Blood Pressure and Autonomic Recovery Following Acute Supramaximal Exercise in Women

Despite the growing popularity of high-intensity anaerobic exercise, little is known about the acute effects of this form of exercise on cardiovascular hemodynamics or autonomic modulation, which might provide insight into the individual assessment of responses to training load. The purpose of this study was to compare blood pressure and autonomic recovery following repeated bouts of acute supramaximal exercise in Black and White women. A convenience sample of twelve White and eight Black young, healthy women were recruited for this study and completed two consecutive bouts of supramaximal exercise on the cycle ergometer with 30 min of recovery in between. Brachial and central aortic blood pressures were assessed by tonometry (SphygmoCor Xcel) at rest and 15-min and 30-min following each exercise bout. Central aortic blood pressure was estimated using brachial pressure waveforms and customized software. Autonomic modulation was measured in a subset of ten participants by heart-rate variability and baroreflex sensitivity. Brachial mean arterial pressure and diastolic blood pressure were significantly higher in Blacks compared to Whites across time (race effect, p = 0.043 and p = 0.049, respectively). Very-low-frequency and low-frequency bands of heart rate variability, which are associated with sympathovagal balance and vasomotor tone, were 22.5% and 24.9% lower, respectively, in Blacks compared to Whites (race effect, p = 0.045 and p = 0.006, respectively). In conclusion, the preliminary findings of racial differences in blood pressure and autonomic recovery following supramaximal exercise warrant further investigations of tailored exercise prescriptions for Blacks and Whites.

A higher resting heart rate is associated with cardiovascular event risk in patients with type 2 diabetes mellitus without known cardiovascular disease

A higher resting heart rate (RHR) is associated with an increased risk of cardiovascular events in patients with type 2 diabetes mellitus (T2DM) and cardiovascular diseases. The aim of this study was to investigate the association between RHR and cardiovascular events in T2DM patients with diabetic retinopathy and without known cardiovascular disease. We analyzed the association between RHR and cardiovascular events, including coronary, cerebral, renal and vascular events or cardiovascular death in T2DM patients with retinopathy and hyperlipidemia without prior cardiovascular events who were enrolled in the EMPATHY study. Data from 4746 patients were analyzed. The median RHR was 76 bpm. Patients were divided into four groups based on their baseline RHR ( < 60, 60-69, 70-79, and ≥80 bpm). Patients with a higher RHR were more likely to be younger and had a higher body mass index, blood pressure value, HbA1c value, and estimated glomerular filtration rate and a lower B-type natriuretic peptide value; they also had a higher proportion of current smoking status, neuropathy, and nephropathy. After adjusting for confounders, including the aforementioned risk factors, a RHR of 70-79 bpm and a RHR ≥ 80 bpm were significantly associated with cardiovascular events (hazard ratio 1.50, 95% CI 1.03-2.20; and hazard ratio 1.62, 95% CI 1.11-2.36; respectively) compared to a RHR of 60-69 bpm. The analysis using restricted cubic splines indicated that the cardiovascular risk seemed to be similarly high when the RHR range was ≥70 bpm. In conclusion, in T2DM patients with diabetic retinopathy and without known cardiovascular disease, a high RHR, particularly ≥70 bpm, was associated with the risk of cardiovascular events compared to a RHR of 60-69 bpm. High resting heart rate (RHR), particularly ≥70 bpm, was associated with the risk of cardiovascular events compared to RHR 60-69 bpm in patients with type 2 diabetes mellitus (T2DM), diabetic retinopathy, and hyperlipidemia, but without known cardiovascular disease.

Disrupted Circadian Rhythm of Epinephrine in Males With Youth-Onset Type 2 Diabetes

Context

Blood pressure and plasma catecholamines normally decline during sleep and rapidly increase in early morning. This is blunted in adults with type 2 diabetes (T2D).

Objective

We hypothesize that increased sympatho-adrenal activity during sleep differentiates youth with T2D from nondiabetic obese youth and lean youth.

Methods

Fasting spot morning and 24-hour urines were collected in obese adolescents with and without T2D, and normal-weight controls. Fractionated free urine catecholamines (epinephrine, norepinephrine, and dopamine) were measured, and the ratio of fasting spot morning to 24-hour catecholamines was calculated.

Results

Urinary 24-hour catecholamine levels were comparable across the 3 groups. Fasting morning epinephrine and the ratio of fasting morning/24-hour epinephrine were higher in youth with T2D (P = 0.004 and P = 0.035, respectively). In males, the ratio of fasting morning/24-hour epinephrine was also higher in youth with T2D (P = 0.005). In females, fasting morning norepinephrine and the ratio of fasting morning/24-hour dopamine were lower in obese youth with and without T2D (P = 0.013 and P = 0.005, respectively) compared with lean youth. Systolic blood pressure was higher in diabetic participants than other groups; males trended higher than females.

Conclusion

Circadian rhythm in catecholamines is disrupted in youth-onset T2D, with a blunted overnight fall in urinary epinephrine in males. Conversely, fasting morning norepinephrine and dopamine levels were lower in obese females with or without T2D. Higher nocturnal catecholamines in males with T2D might associate with, or predispose to, hypertension and cardiovascular complications. Lower catecholamine excretion in females with obesity might serve an adaptive, protective role.

Effects of whole-body vibration on reproductive physiology in a rat model of whole-body vibration

Findings from epidemiological studies suggest that occupational exposure to whole-body vibration (WBV) may increase the risk of miscarriage and contribute to a reduction in fertility rates in both men and women. However, workers exposed to WBV may also be exposed to other risk factors that contribute to reproductive dysfunction. The goal of this experiment was to examine the effects of WBV on reproductive physiology in a rat model. Male and female rats were exposed to WBV at the resonant frequency of the torso (31.5 Hz, 0.3 g amplitude) for 4 hr/day for 10 days. WBV exposure resulted in a significant reduction in number of developing follicles, and decrease in circulating estradiol concentrations, ovarian luteinizing hormone receptor protein levels, and marked changes in transcript levels for several factors involved in follicular development, cell cycle, and steroidogenesis. In males, WBV resulted in a significant reduction in spermatids and circulating prolactin levels, elevation in number of males having higher circulating testosterone concentrations, and marked alterations in levels of transcripts associated with oxidative stress, inflammation, and factors involved in regulating the cell cycle. Based upon these findings data indicate that occupational exposure to WBV contributes to adverse alterations in reproductive physiology in both genders that may lead to reduction in fertility.

Heart Rate Recovery, Central Systolic Pressure, and Augmentation Index in Young Healthy Individuals

Purpose

Measuring heart rate recovery (HRR) holds valuable cardiovascular information and requires minimal technical skill and cost. Understanding the associations between HRR and more robust cardiovascular indicators, such as central systolic blood pressure (CSBP), can provide valuable cardiovascular information with less involvement. CSBP is a strong predictor of certain cardiovascular diseases. The study aims to examine the association between measures of HRR and CSBP and the augmentation index (AIx) in a group of young, healthy individuals and based on sex.

Participants and Methods

One-hundred and seven participants (men – 55, women – 52) were measured for HRR at one minute (HRR₁) and two minutes (HRR₂) after maximum oxygen consumption (VO_2max) testing, CSBP, and the AIx at a heart rate of 75 beats∙min⁻¹ (AIx@75).

Results

The Pearson correlation indicated no association between HRR₁, HRR₂, and CSBP in men and women combined: r = 0.06, P = 0.53; r = 0.05, P = 0.59, respectively, or based on sex: men = r = 0.01, P = 0.95; r = 0.04, P = 0.79, respectively, and women = r = −0.05, P = 0.75; r = −0.09, P = 0.52, respectively. However, there were associations between HRR₁ and AIx@75 in men and women combined: r = −0.37, P < 0.001, and based on sex: men = r = −0.31, P = 0.02, and women = r = −0.38, P < 0.01.

Conclusion

Measures of HRR were not associated with CSBP in a combined group of young men and women or based on sex. Most measures of HRR, especially those established by parasympathetic nervous activity, were associated with lower AIx@75. Though measures of HRR might be good indicators of cardiovascular disease, they might not be good indicators of CSBP in young, healthy individuals.

Differential influences of dietary sodium on blood pressure regulation based on race and sex

There are clear differences between men and women, and differences among races, in the incidence and prevalence of hypertension. Furthermore, there is extensive inter-individual variability among humans in the extent to which sodium ingestion alters blood pressure. Orthostatic intolerance and orthostatic hypotension are more common in women; these are often treated with a high salt diet, which has variable efficacy in increasing blood volume and blood pressure. Conversely, people with certain forms of hypertension are often counseled to decrease their sodium intake. Non-Hispanic Black men and women have higher rates of hypertension compared to non-Hispanic White men and women and other racial/ethnic groups. In aggregate, Black women appear to have better orthostatic tolerance than White women. In the present paper, we summarize and evaluate the current evidence for mechanisms of blood pressure regulation in men and women, as well as differences between Black and White groups, with a focus on cardiovascular responses to salt and differences among these groups. We also provide a brief review of factors that are not traditionally considered to be "biological" - such as socio-economic disparities resulting from historic and contemporary inequity across racial groups. These non-biological factors have direct and substantial influences on cardiovascular mechanisms, as well as implications for the influences of salt and sodium intake on blood pressure and cardiovascular health. We conclude that both biological and socio-economic factors provide critical modulating influences when considering the impacts of sodium on cardiovascular health as functions of race and sex.

The Impact of Fitness Status on Vascular and Baroreceptor Function in Healthy Women and Men

BACKGROUND

Chronic endurance exercise training elicits desirable physiological adaptations in the cardiovascular system. The volume of exercise training required to generate healthy adaptations is unclear. This study assessed the effects of differing exercise training levels on arterial stiffness, compliance, and autonomic function.

METHODS

Eighty healthy adults (38.5 ± 9.7 years; 44% female) defined as endurance-trained (ET, n = 29), normally active (NA, n = 27), or inactive (IN, n = 24) participated. Cardiovascular markers, including hemodynamics, large arterial compliance and small arterial compliance (LAC and SAC), carotid-femoral pulse wave velocity (PWV), and spontaneous baroreceptor sensitivity (BRS) were assessed.

RESULTS

ET showed significantly greater LAC values (21.4 ± 6.5) than NA (16.9 ± 2.5; p = 0.002) and IN (14.7 ± 3.2 mL × mm Hg × 10; p = 0.028). Values for SAC and BRS were significantly higher in ET than IN (p < 0.001 and p = 0.028, respectively), but not NA. Compared to IN, PWV values for ET and NA were significantly lower (p < 0.003). After adjusting for covariates (age, sex, and SBP), significant associations with cardiovascular fitness status were noted for all markers but BRS.

CONCLUSION

Endurance exercise increases LAC likely due to high-volume training; however, lower volumes of physical activity may be sufficient to positively benefit vascular health overall.

Regional differences in office and self-measured home heart rates in Asian hypertensive patients: AsiaBP@Home study

Increased heart rate is a predictor of cardiovascular disease, heart failure, and all‐cause mortality. In those with high heart rates, interventions for heart rate reduction have been associated with reductions in coronary events. Asia is a diverse continent, and the prevalences of hypertension and cardiovascular disease differ among its countries. The present analysis of AsiaBP@Home study data investigated differences among resting heart rates (RHRs) in 1443 hypertensive patients from three Asian regions: East Asia (N = 595), Southeast Asia (N = 680), and South Asia (N = 168). This is the first study to investigate self‐measured RHR values in different Asian countries/regions using the same validated home BP monitoring device (Omron HEM‐7130‐AP/HEM‐7131‐E). Subjects in South Asia had higher RHR values compared with the other two regions, and the regional tendency found in RHR values was different from that found in BP values. Even after adjusting for age, sex, BMI, habitual alcohol consumption, current smoking habit, shift worker, hyperlipidemia, diabetes, chronic kidney disease, history of heart failure, and beta‐blocker use, both office and home RHR values in South Asia were the highest among Asia (mean values ± SE of office: East Asia [E] 75.2 ± 1.5 bpm, Southeast Asia [Se] 76.7 ± 1.5 bpm, South Asia [S] 81.9 ± 1.4 bpm; home morning: [E] 69.0 ± 1.2 bpm, [Se] 72.9 ± 1.2 bpm, [S] 74.9 ± 1.1 bpm; home evening: [E] 74.6 ± 1.2 bpm, [Se] 78.3 ± 1.2 bpm, [S] 83.8 ± 1.1 bpm). Given what is known about the impact of RHR on heart disease, our findings suggest the possible benefit of regionally tailored clinical strategies for cardiovascular disease prevention.