Perturbed autonomic nervous system function in metabolic syndrome

Parental History of Hypertension: A Risk for Autonomic Dysfunction and Metabolic and Vascular Derangement in Normotensive Male Offspring

BACKGROUND

Children of hypertensive parents have an increased propensity of developing hypertension, at an age very much prior to their parents. Understanding the pathophysiology of hypertension in such young individuals, especially baroreflex sensitivity (BRS), is necessary. Reduced heart rate variability (HRV), insulin resistance (IR), dyslipidemia, and decreased vasodilatory adipokines, namely, apelin and relaxin, in normotensives may predispose to the onset of hypertension. Thus, this study compared autonomic functions, vascular markers, and metabolic profiles between normotensive male offspring with and without parental hypertension.

METHODS

This analytical cross-sectional study comprised 40 male normotensive offspring of hypertensive parents, aged 18-35 years, recruited as the study group and 40 age- and body mass index (BMI)-matched normotensive male offspring with non-hypertensive parents enrolled as controls. Cardiovascular autonomic functions, including BRS, HRV, diastolic blood pressure response to isometric handgrip test (ΔDBPIHG), Valsalva ratio, and metabolic and vascular markers, were assessed.

RESULTS

The study group exhibited reduced BRS, HRV, and Valsalva ratio and higher ΔDBPIHG compared to controls, indicating impaired autonomic functions. The study group had higher IR and triglyceride levels and reduced apelin and relaxin levels. BRS showed significant correlations with HRV, Valsalva ratio, ΔDBPIHG, and metabolic and vascular markers.

CONCLUSIONS

Normotensive male offspring of hypertensive parents exhibit impaired autonomic functions, as evidenced by reduced BRS, HRV, and Valsalva ratio. Additionally, they have higher IR, dyslipidemia, and decreased levels of vasodilatory adipokines, indicating an increased risk for future hypertension development. These findings signify that early identification of hypertensive potential in this high-risk population is warranted, which would enable taking necessary preventive measures.

Brain Dopamine-Clock Interactions Regulate Cardiometabolic Physiology: Mechanisms of the Observed Cardioprotective Effects of Circadian-Timed Bromocriptine-QR Therapy in Type 2 Diabetes Subjects

Despite enormous global efforts within clinical research and medical practice to reduce cardiovascular disease(s) (CVD), it still remains the leading cause of death worldwide. While genetic factors clearly contribute to CVD etiology, the preponderance of epidemiological data indicate that a major common denominator among diverse ethnic populations from around the world contributing to CVD is the composite of Western lifestyle cofactors, particularly Western diets (high saturated fat/simple sugar [particularly high fructose and sucrose and to a lesser extent glucose] diets), psychosocial stress, depression, and altered sleep/wake architecture. Such Western lifestyle cofactors are potent drivers for the increased risk of metabolic syndrome and its attendant downstream CVD. The central nervous system (CNS) evolved to respond to and anticipate changes in the external (and internal) environment to adapt survival mechanisms to perceived stresses (challenges to normal biological function), including the aforementioned Western lifestyle cofactors. Within the CNS of vertebrates in the wild, the biological clock circuitry surveils the environment and has evolved mechanisms for the induction of the obese, insulin-resistant state as a survival mechanism against an anticipated ensuing season of low/no food availability. The peripheral tissues utilize fat as an energy source under muscle insulin resistance, while increased hepatic insulin resistance more readily supplies glucose to the brain. This neural clock function also orchestrates the reversal of the obese, insulin-resistant condition when the low food availability season ends. The circadian neural network that produces these seasonal shifts in metabolism is also responsive to Western lifestyle stressors that drive the CNS clock into survival mode. A major component of this natural or Western lifestyle stressor-induced CNS clock neurophysiological shift potentiating the obese, insulin-resistant state is a diminution of the circadian peak of dopaminergic input activity to the pacemaker clock center, suprachiasmatic nucleus. Pharmacologically preventing this loss of circadian peak dopaminergic activity both prevents and reverses existing metabolic syndrome in a wide variety of animal models of the disorder, including high fat-fed animals. Clinically, across a variety of different study designs, circadian-timed bromocriptine-QR (quick release) (a unique formulation of micronized bromocriptine-a dopamine D2 receptor agonist) therapy of type 2 diabetes subjects improved hyperglycemia, hyperlipidemia, hypertension, immune sterile inflammation, and/or adverse cardiovascular event rate. The present review details the seminal circadian science investigations delineating important roles for CNS circadian peak dopaminergic activity in the regulation of peripheral fuel metabolism and cardiovascular biology and also summarizes the clinical study findings of bromocriptine-QR therapy on cardiometabolic outcomes in type 2 diabetes subjects.

McDAPS: A multi-channel physiological signals display and analysis system for clinical researchers

We introduce McDAPS, an interactive software for assessing autonomic imbalance from non-invasive multi-channel physiological recordings. McDAPS provides a graphical user interface for data visualization, beat-to-beat processing and interactive analyses. The software extracts beat-to-beat RR interval systolic blood pressure, diastolic blood pressure, the pulse amplitude of photoplethysmogram and the pulse-to-pulse interval. The analysis modules include stationary and time-varying power spectral analyses, moving-correlation analysis and univariate analyses. Analyses can also be performed in batch mode if multiple datasets have to be processed in the same way. The program exports results in standard CSV format. McDAPS runs in MATLAB, and is supported on MS Windows and MAC OS systems. The MATLAB source code is available at https://github.com/thuptimd/McDAPS.git.

O-GlcNAcylation is crucial for sympathetic neuron development, maintenance, functionality and contributes to peripheral neuropathy

O-GlcNAcylation is a post-translational modification (PTM) that regulates a wide range of cellular functions and has been associated with multiple metabolic diseases in various organs. The sympathetic nervous system (SNS) is the efferent portion of the autonomic nervous system that regulates metabolism of almost all organs in the body. How much the development and functionality of the SNS are influenced by O-GlcNAcylation, as well as how such regulation could contribute to sympathetic neuron (symN)-related neuropathy in diseased states, remains unknown. Here, we assessed the level of protein O-GlcNAcylation at various stages of symN development, using a human pluripotent stem cell (hPSC)-based symN differentiation paradigm. We found that pharmacological disruption of O-GlcNAcylation impaired both the growth and survival of hPSC-derived symNs. In the high glucose condition that mimics hyperglycemia, hPSC-derived symNs were hyperactive, and their regenerative capacity was impaired, which resembled typical neuronal defects in patients and animal models of diabetes mellitus. Using this model of sympathetic neuropathy, we discovered that O-GlcNAcylation increased in symNs under high glucose, which lead to hyperactivity. Pharmacological inhibition of O-GlcNAcylation rescued high glucose-induced symN hyperactivity and cell stress. This framework provides the first insight into the roles of O-GlcNAcylation in both healthy and diseased human symNs and may be used as a platform for therapeutic studies.

Sleep Duration/Quality With Health Outcomes: An Umbrella Review of Meta-Analyses of Prospective Studies

Background

To quantitatively evaluate the evidence of duration and quality of sleep as measured by multiple health outcomes.

Methods

This review is registered with PROSPERO, number CRD42021235587. We systematically searched three databases from inception until November 15, 2020. For each meta-analysis, the summary effect size using fixed and random effects models, the 95% confidence interval, and the 95% prediction interval were assessed; heterogeneity, evidence of small-study effects, and excess significance bias were also estimated. According to the above metrics, we evaluated the credibility of each association.

Results

A total of 85 meta-analyses with 36 health outcomes were included in the study. We observed highly suggestive evidence for an association between long sleep and an increased risk of all-cause mortality. Moreover, suggestive evidence supported the associations between long sleep and 5 increased risk of health outcomes (stroke, dyslipidaemia, mortality of coronary heart disease, stroke mortality, and the development or death of stroke); short sleep and increased risk of overweight and/or obesity; poor sleep quality and increased risk of diabetes mellitus and gestational diabetes mellitus.

Conclusions

Only the evidence of the association of long sleep with an increased risk of all-cause mortality was graded as highly suggestive. Additional studies are needed to be conducted.

Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42021235587

Interplay between baroreflex sensitivity, obesity and related cardiometabolic risk factors (Review)

The baroreflex represents a rapid negative feedback system implicated in blood pressure regulation, which aims to prevent blood pressure variations by regulating peripheral vascular tone and cardiac output. The aim of the present review was to highlight the association between baroreflex sensitivity (BRS) and obesity, including factors associated with obesity, such as metabolic syndrome, hypertension, cardiovascular disease and diabetes. For the present review, a literature search was conducted using the PubMed database until August 21, 2021. The searched terms included ‘baroreflex’, and other terms such as ‘sensitivity’, ‘obesity’, ‘metabolic syndrome’, ‘hypertension’, ‘diabetes’, ‘gender’, ‘aging’, ‘children’, ‘adolescents’, ‘physical activity’, ‘bariatric surgery’, ‘autonomous nervous system’ and ‘cardiometabolic risk factors’. Obesity and its related metabolic disorders can influence baroreflex functionality and decrease BRS, mostly by potentiating sympathetic nervous system activity. Obesity induces inflammation, which can increase sympathetic system activity and lead to a higher incidence of cardiovascular events. Obesity also represents an important risk factor for hypertension through numerous mechanisms; in this setting, dysfunctional baroreceptors are not able to protect against constantly elevated blood pressure. Furthermore, diabetes mellitus and oxidative stress result in deterioration of BRS, whereas aging is also generally related to reduced cardiovagal BRS. Differences in BRS have also been observed between men and women, and overall cardiovagal BRS in healthy women is less intense compared with that in men. BRS appears lower in children with obesity compared with that in children of a healthy weight. Notably, physical exercise can increase BRS in both hypertensive and normotensive subjects, and BRS can also be significantly improved following bariatric surgery and weight loss. In conclusion, obesity and its related metabolic disorders may influence baroreflex functionality and decrease BRS, and baroreceptors cannot protect against the constantly elevated blood pressure in obesity. However, following bariatric surgery and weight loss, BRS can be significantly improved. The present review summarizes the role of obesity and related metabolic risk factors in BRS, providing details on possible mechanisms and shedding light on their interplay leading to autonomic neuropathy.

Association of sleep quality with glycemic variability assessed by flash glucose monitoring in patients with type 2 diabetes

BACKGROUND

Deterioration of sleep quality has been reported to contribute to the incidence of diabetes and may be responsible for glycemic status in diabetes. The present study explored the relationship between sleep quality and glycemic variability in patients with type 2 diabetes (T2D).

METHODS

We recruited 111 patients with T2D for this cross-sectional study. Each patient underwent flash glucose monitoring for 14 days to obtain glycemic variability parameters, such as standard deviation of glucose (SD), coefficient of variation of glucose (CV), mean amplitude of glycemic excursions (MAGE), mean of daily differences (MODD), and time in glucose range of 3.9-10 mmol/L (TIR_3.9-10). After 14 days of flash glucose monitoring, each patient received a questionnaire on the Pittsburgh Sleep Quality Index (PSQI) to evaluate subjective sleep quality. HbA1c was also collected to assess average glucose.

RESULTS

HbA1c was comparable among the subgroups of PSQI score tertiles. Across ascending tertiles of PSQI scores, SD, CV and MAGE were increased, while TIR_3.9-10 was decreased (p for trend  <  0.05), but not MODD (p for trend  =  0.090). Moreover, PSQI scores were positively correlated with SD, CV, MODD and MAGE (r =  0.322, 0.361, 0.308 and 0.354, respectively, p  <  0.001) and were inversely correlated with TIR_3.9-10 (r  =  - 0.386, p  <  0.001). After adjusting for other relevant data by multivariate linear regression analyses, PSQI scores were independently responsible for SD (β  =  0.251, t  =  2.112, p  =  0.041), CV (β  =  0.286, t  =  2.207, p  =  0.033), MAGE (β  =  0.323, t  =  2.489, p  =  0.018), and TIR_3.9-10 (β  =  - 0.401, t  =  - 3.930, p  <  0.001) but not for MODD (β  =  0.188, t  =  1.374, p  =  0.177).

CONCLUSIONS

Increased glycemic variability assessed by flash glucose monitoring was closely associated with poor subjective sleep quality evaluated by the PSQI in patients with T2D.

Infant weight-for-length gain associated with autonomic nervous system reactivity

BACKGROUND

Research suggests that children's health and well-being are supported by core adaptive systems, including the autonomic nervous system (ANS). Despite evidence for the importance of adulthood ANS regulation in the development of disease, few studies have examined how early development may influence emerging ANS function. Therefore, we examined how infant adiposity gain during early infancy related to ANS regulation at 6 months.

METHODS

Infant weight and length were abstracted from birth records and measured during the 6-month assessment in a low-income, racially/ethnically diverse sample (N = 60). WHO-standardized weight-for-length-gain change was calculated across the first 6 months of life. ANS reactivity was measured as the combined sympathetic (i.e., pre-ejection period) and parasympathetic (i.e., respiratory sinus arrhythmia) nervous system responses during the developmentally challenging Still Face Paradigm (SFP). ANS "classic reactivity" response was characterized by paired sympathetic activation and parasympathetic withdrawal.

RESULTS

Lower weight-for-length gain in the first 6 months predicted classic reactivity during still face. However, greater weight-for-length gain predicted "classic reactivity" during the reunion, when infants were expected to recover, suggesting autonomic dysregulation.

CONCLUSIONS

These findings suggest an association between early life adiposity gain and the development of infant ANS regulation.

IMPACT

Adiposity gain during early infancy was associated with autonomic nervous system regulation at 6 months. This study identifies early adiposity gain (greater than average infant weight-for-length gain) as a risk for ANS dysregulation. This research focuses on a critical developmental period of ANS plasticity. If confirmed, findings can be used to inform early intervention programs targeting obesity prevention and to promote self-regulation.

Experimental dopaminergic neuron lesion at the area of the biological clock pacemaker, suprachiasmatic nuclei (SCN) induces metabolic syndrome in rats

BACKGROUND

The daily peak in dopaminergic neuronal activity at the area of the biological clock (hypothalamic suprachiasmatic nuclei [SCN]) is diminished in obese/insulin resistant vs lean/insulin sensitive animals. The impact of targeted lesioning of dopamine (DA) neurons specifically at the area surrounding (and that communicate with) the SCN (but not within the SCN itself) upon glucose metabolism, adipose and liver lipid gene expression, and cardiovascular biology in normal laboratory animals has not been investigated and was the focus of this study.

METHODS

Female Sprague-Dawley rats received either DA neuron neurotoxic lesion by bilateral intra-cannula injection of 6-hydroxydopamine (2-4 μg/side) or vehicle treatment at the area surrounding the SCN at 20 min post protriptyline ip injection (20 mg/kg) to protect against damage to noradrenergic and serotonergic neurons.

RESULTS

At 16 weeks post-lesion relative to vehicle treatment, peri-SCN area DA neuron lesioning increased weight gain (34.8%, P < 0.005), parametrial and retroperitoneal fat weight (45% and 90% respectively, P < 0.05), fasting plasma insulin, leptin and norepinephrine levels (180%, 71%, and 40% respectively, P < 0.05), glucose tolerance test area under the curve (AUC) insulin (112.5%, P < 0.05), and insulin resistance (44%-Matsuda Index, P < 0.05) without altering food consumption during the test period. Such lesion also induced the expression of several lipid synthesis genes in adipose and liver and the adipose lipolytic gene, hormone sensitive lipase in adipose (P < 0.05 for all). Liver monocyte chemoattractant protein 1 (a proinflammatory protein associated with metabolic syndrome) gene expression was also significantly elevated in peri-SCN area dopaminergic lesioned rats. Peri-SCN area dopaminergic neuron lesioned rats were also hypertensive (systolic BP rose from 157 ± 5 to 175 ± 5 mmHg, P < 0.01; diastolic BP rose from 109 ± 4 to 120 ± 3 mmHg, P < 0.05 and heart rate increase from 368 ± 12 to 406 ± 12 BPM, P < 0.05) and had elevated plasma norepinephrine levels (40% increased, P < 0.05) relative to controls.

CONCLUSIONS

These findings indicate that reduced dopaminergic neuronal activity in neurons at the area of and communicating with the SCN contributes significantly to increased sympathetic tone and the development of metabolic syndrome, without effect on feeding.

A Focused Review of the Metabolic Side-Effects of Clozapine

The second generation antipsychotic drug clozapine represents the most effective pharmacotherapy for treatment-resistant psychosis. It is also associated with low rates of extrapyramidal symptoms and hyperprolactinemia compared to other antipsychotic drugs. However, clozapine tends to be underutilized in clinical practice due to a number of disabling and serious side-effects. These are characterized by a constellation of metabolic side-effects which include dysregulation of glucose, insulin, plasma lipids and body fat. Many patients treated with clozapine go on to develop metabolic syndrome at a higher rate than the general population, which predisposes them for Type 2 diabetes mellitus and cardiovascular disease. Treatments for the metabolic side-effects of clozapine vary in their efficacy. There is also a lack of knowledge about the underlying physiology of how clozapine exerts its metabolic effects in humans. In the current review, we focus on key studies which describe how clozapine affects each of the main symptoms of the metabolic syndrome, and cover some of the treatment options. The clinical data are then discussed in the context of preclinical studies that have been conducted to identify the key biological substrates involved, in order to provide a better integrated overview. Suggestions are provided about key areas for future research to better understand how clozapine causes metabolic dysregulation.

Parasympathetic Response Patterns are Associated with Metabolic Syndrome Among Older Women but Not Men

Background

Little is known about the role of physiological stress responses in metabolic syndrome (MetS).

Purpose

To examine whether patterns of autonomic response to psychological stress are associated with MetS and whether this association is moderated by sex

Methods

1121 men and women (M_age = 65.3 ± 6.77 years) with and without coronary artery disease (CAD) underwent an anger recall stressor task. Heart rate and heart-rate variability (HRV; HF, LF/HF) were assessed. Clusters of participants showing similar patterns of response across baseline, stress, and recovery periods were created using ACECLUS and FASTCLUS in SAS. Logistic regressions included clusters and interaction between clusters and sex as independent variables, controlling for relevant covariates. ANCOVAs were conducted in secondary analyses utilizing a continuous composite representation of MetS.

Results

Men and women showing greater tonic and phasic HR elevations were more likely to meet MetS criteria (OR = 1.45, [95% CI = 1.02–2.07], p = .037). HF-HRV cluster interacted significantly with sex (p < .001) to predict MetS. In women, those with significant parasympathetic withdrawal to stress and poor recovery were more likely to have MetS than women with a more moderate response (OR = 2.56, [95% CI = 1.23–5.41], p = .013). Women who displayed stress-related parasympathetic activation were also at greater risk of MetS (OR = 2.30, [95% CI = 1.30–4.07], p = .004). Results using a continuous measure of MetS were generally consistent with these findings.

Conclusion

Among older participants with CAD or other noncardiovascular disease, hyperreactivity to stress was associated with greater prevalence of MetS, particularly in women. Consistent with emerging literature, women who showed blunting or activation of parasympathetic responses to stress were similarly at greater risk.

The effect of sleep impairment on gestational diabetes mellitus: a systematic review and meta-analysis of cohort studies

OBJECTIVE

This systematic review and meta-analysis evaluated the influence of sleep duration or impairment (poor sleep quality, snoring, and obstructive sleep apnea [OSA]) on gestational diabetes mellitus (GDM) risk.

METHODS

PubMed, Embase, EBSCO, and WOS databases were searched up to March 4th, 2019. Cohort studies were included and relative risk (RR) with 95% confidence interval (CI) were used as the measure of effects. Heterogeneity was assessed by the Chi-squared and I² tests. Subgroup analyses, sensitivity analysis, and dose-response analysis were performed. The overall quality of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

A total of 16 studies with 2,551,017 pregnant women and 142,103 GDM cases were included in this study. Both short and long sleep duration were associated with increased risk of GDM. There was a U-shaped relationship between sleep duration and GDM risk (P_{-nonlinearity} < 0.001), and pregnant women with 8 h of sleep presented lower GDM risk. Poor sleep quality, snoring and OSA also increased the subsequent risk of GDM.

CONCLUSIONS

Pregnant women should be made aware of the benefits of proper sleep, and those with poor sleep quality, snoring, and OSA should be screened for GDM.

Circadian-timed quick-release bromocriptine lowers elevated resting heart rate in patients with type 2 diabetes mellitus

OBJECTIVE

Sympathetic nervous system (SNS) overactivity is a risk factor for insulin resistance and cardiovascular disease (CVD). We evaluated the impact of bromocriptine-QR, a dopamine-agonist antidiabetes medication, on elevated resting heart rate (RHR) (a marker of SNS overactivity in metabolic syndrome), blood pressure (BP) and the relationship between bromocriptine-QR's effects on RHR and HbA1c in type 2 diabetes subjects.

DESIGN AND SUBJECTS

RHR and BP changes were evaluated in this post hoc analysis of data from a randomized controlled trial in 1014 type 2 diabetes subjects randomized to bromocriptine-QR vs placebo added to standard therapy (diet ± ≤2 oral antidiabetes medications) for 24 weeks without concomitant antihypertensive or antidiabetes medication changes, stratified by baseline RHR (bRHR).

RESULTS

In subjects with bRHR ≥70 beats/min, bromocriptine-QR vs placebo reduced RHR by -3.4 beats/min and reduced BP (baseline 130/79; systolic, diastolic, mean arterial BP reductions [mm Hg]: -3.6 [P = .02], -1.9 [P = .05], -2.5 [P = .02]). RHR reductions increased with higher baseline HbA1c (bHbA1c) (-2.7 [P = .03], -5 [P = .002], -6.1 [P = .002] with bHbA1c ≤7, >7, ≥7.5%, respectively] in the bRHR ≥70 group and more so with bRHR ≥80 (-4.5 [P = .07], -7.8 [P = .015], -9.9 [P = .005]). Subjects with bRHR <70 had no significant change in RHR or BP. With bHbA1c ≥7.5%, %HbA1c reductions with bromocriptine-QR vs placebo were -0.50 (P = .04), -0.73 (P = .005) and -1.22 (P = .008) with bRHR <70, ≥70 and ≥80, respectively. With bRHR ≥70, the magnitude of bromocriptine-QR-induced RHR reduction was an independent predictor of bromocriptine-QR's HbA1c lowering effect.

CONCLUSION

Bromocriptine-QR lowers elevated RHR with concurrent decrease in BP and hyperglycaemia. These findings suggest a potential sympatholytic mechanism contributing to bromocriptine-QR's antidiabetes effect and potentially its previously demonstrated effect to reduce CVD events.

Negative Affect-Related Autonomic Arousal Mediates the Association between Baroreflex Dysfunction and Insulin Resistance in Non-Diabetic Young Adults

Autonomic dysfunction, in particular under-regulation of heart rate (HR) by the baroreflex, is implicated in development of insulin resistance (IR). According to reactivity hypothesis, sympathetic response to stressors may be more sensitive at predicting IR than baroreceptor sensitivity (BRS), a baseline measure of baroreflex functioning. Using ecological momentary assessment (EMA) of negative affect coupled with minute-to-minute HR and heart-rate variability (HRV) monitoring, we examined whether negative affect (NA)-related autonomic arousal mediates the association of BRS with IR. At baseline, BRS was measured, and fasting serum glucose and insulin levels were collected from 178 young adults (18-39 years old), from which homeostasis model assessment of IR (HOMA-IR) and beta-cell functioning (HOMA %B) were derived. Participants subsequently underwent one day of Holter HR and HRV monitoring while reporting negative affect levels via EMA. Multilevel modeling was used to assess the associations of momentary negative affect with HR and low- (LF) and high-frequency (HF) HRV during the 5-minute intervals following each EMA reading. Structural equation modeling was then used to determine whether individual differences in these associations mediated the association of BRS with IR, measured by HOMA-IR, HOMA %B, and insulin levels. As predicted, BRS was negatively associated with the IR (β = -.17, p = .024). However, NA-related autonomic arousal mediated their association, accounting for 56% of the covariance between BRS and IR. Not only do these results provide support for reactivity hypothesis, they reveal a potential point of intervention in the treatment of affective dysregulation.

Prenatal Exposure to PM2.5 and Cardiac Vagal Tone during Infancy: Findings from a Multiethnic Birth Cohort

BACKGROUND

The autonomic nervous system plays a key role in maintaining homeostasis and responding to external stimuli. In adults, exposure to fine particulate matter (PM2.5) has been associated with reduced heart rate variability (HRV), an indicator of cardiac autonomic control.

OBJECTIVES

Our goal was to investigate the associations of exposure to fine particulate matter (PM2.5) with HRV as an indicator of cardiac autonomic control during early development.

METHODS

We studied 237 maternal-infant pairs in a Boston-based birth cohort. We estimated daily residential PM2.5 using satellite data in combination with land-use regression predictors. In infants at 6 months of age, we measured parasympathetic nervous system (PNS) activity using continuous electrocardiogram monitoring during the Repeated Still-Face Paradigm, an experimental protocol designed to elicit autonomic reactivity in response to maternal interaction and disengagement. We used multivariable linear regression to examine average PM2.5 exposure across pregnancy in relation to PNS withdrawal and activation, indexed by changes in respiration-corrected respiratory sinus arrhythmia (RSAc)-an established metric of HRV that reflects cardiac vagal tone. We examined interactions with infant sex using cross-product terms.

RESULTS

In adjusted models we found that a 1-unit increase in PM2.5 (in micrograms per cubic meter) was associated with a 3.53% decrease in baseline RSAc (95% CI: -6.96, 0.02). In models examining RSAc change between episodes, higher PM2.5 was generally associated with reduced PNS withdrawal during stress and reduced PNS activation during recovery; however, these associations were not statistically significant. We did not observe a significant interaction between PM2.5 and sex.

DISCUSSION

Prenatal exposure to PM2.5 may disrupt cardiac vagal tone during infancy. Future research is needed to replicate these preliminary findings. https://doi.org/10.1289/EHP4434.

Conceptualization of a Parasympathetic Endocrine System

We here propose a parasympathetic endocrine system (PES) comprised of circulating peptides released from secretory cells in the gut, significantly modulated by vagal projections from the dorsal motor nucleus of the vagus (DMV). While most of these gut peptides mediate well-described satiety and digestive effects that increase parasympathetic control of digestion (Lee et al., 1994; Gutzwiller et al., 1999; Klok et al., 2007), they also have actions that are far-reaching and increase parasympathetic signaling broadly throughout the body. The actions beyond satiety that peptides like somatostatin, cholecystokinin, glucagon-like peptide 1, and vasoactive intestinal peptide have been well-examined, but not in a systematic way. Consideration has been given to the idea that these and other gut-derived peptides are part of an endocrine system has been partially considered (Rehfeld, 2012; Drucker, 2016), but that it is coordinated through parasympathetic control and may act to increase the actions of parasympathetic projections has not been formalized before. Here only gut-derived hormones are included although there are potentially other parasympathetically mediated factors released from other sites like lung and liver (Drucker, 2016). The case for the existence of the PES with the DMV as its integrative controller will be made through examination of an anatomical substrate and evidence of physiological control mechanisms as well as direct examples of PES antagonism of sympathetic signaling in mammals, including humans. The implications for this conceptual understanding of a PES reframe diseases like metabolic syndrome and may help underscore the role of the autonomic nervous system in the associated symptoms.

Quantitative Assessment of Autonomic Regulation of the Cardiac System

Autonomic neural system (ANS) regulates the circulation to provide optimal perfusion of every organ in accordance with its metabolic needs, and the quantitative assessment of autonomic regulation is crucial for personalized medicine in cardiovascular diseases. In this paper, we propose the Dystatis to quantitatively evaluate autonomic regulation of the human cardiac system, based on homeostatis and probabilistic graphic model, where homeostatis explains ANS regulation while the probability graphic model systematically defines the regulation process for quantitative assessment. The indices and measurement methods for three well-designed scenarios are also illustrated to evaluate the proposed Dystatis: (1) heart rate variability (HRV), blood pressure variability (BPV), and respiration synchronization (Synch) in resting situation; (2) chronotropic competence indices (CCI) in graded exercise testing; and (3) baroreflex sensitivity (BRS), sympathetic nerve activity (SNA), and parasympathetic nerve activity (PNA) in orthostatic testing. The previous clinical results have shown that the proposed method and indices for autonomic cardiac system regulation have great potential in prediction, diagnosis, and rehabilitation of cardiovascular diseases, hypertension, and diabetes.

Interaction of Diet and Ozone Exposure on Oxidative Stress Parameters within Specific Brain Regions of Male Brown Norway Rats

Oxidative stress (OS) contributes to the neurological and cardio/pulmonary effects caused by adverse metabolic states and air pollutants such as ozone (O₃). This study explores the interactive effects of O₃ and diet (high-fructose (FRUC) or high–fat (FAT)) on OS in different rat brain regions. In acute exposure, there was a decrease in markers of reactive oxygen species (ROS) production in some brain regions by diet and not by O₃. Total antioxidant substances (TAS) were increased in the cerebellum (CER) and frontal cortex (FC) and decreased in the striatum (STR) by both diets irrespective of O₃ exposure. Protein carbonyls (PC) and total aconitase decreased in some brain regions irrespective of exposure. Following subacute exposure, an increase in markers of ROS was observed in both diet groups. TAS was increased in the FC (FAT only) and there was a clear O₃ effect where TAS was increased in the FC and STR. Diet increased PC formation within the CER in the FAT group, while the hippocampus showed a decrease in PC after O₃ exposure in controls. In general, these results indicate that diet/O₃ did not have a global effect on brain OS parameters, but showed some brain region- and OS parameter-specific effects by diets.

Associations of immunometabolic risk factors with symptoms of depression and anxiety: The role of cardiac vagal activity

OBJECTIVES

This study examined 1) the cross-sectional relationships between symptoms of depression/anxiety and immunometabolic risk factors, and 2) whether these relationships might be explained in part by cardiac vagal activity.

METHODS

Data were drawn from the Adult Health and Behavior registries (n = 1785), comprised of community dwelling adults (52.8% women, aged 30-54). Depressive symptoms were measured with the Center for Epidemiological Studies Depression Scale (CES-D) and the Beck Depression Inventory-II (BDI-II), and anxious symptoms with the Trait Anxiety scale of the State-Trait Anxiety Inventory (STAI-T). Immunometabolic risk factors included fasting levels of triglycerides, high-density lipoproteins, glucose, and insulin, as well as blood pressure, waist circumference, body mass index, C-reactive protein, and interleukin-6. Measures of cardiac autonomic activity were high- and low-frequency indicators of heart rate variability (HRV), standard deviation of normal-to-normal R-R intervals, and the mean of absolute and successive differences in R-R intervals.

RESULTS

Higher BDI-II scores, in contrast to CES-D and STAI-T scores, were associated with increased immunometabolic risk and decreased HRV, especially HRV likely reflecting cardiac vagal activity. Decreased HRV was also associated with increased immunometabolic risk. Structural equation models indicated that BDI-II scores may relate to immunometabolic risk via cardiac vagal activity (indirect effect: β = .012, p = .046) or to vagal activity via immunometabolic risk (indirect effect: β = -.015, p = .021).

CONCLUSIONS

Depressive symptoms, as measured by the BDI-II, but not anxious symptoms, were related to elevated levels of immunometabolic risk factors and low cardiac vagal activity. The latter may exhibit bidirectional influences on one another in a meditational framework. Future longitudinal, intervention, an nonhuman animal work is needed to elucidate the precise and mechanistic pathways linking depressive symptoms to immune, metabolic, and autonomic parameters of physiology that predispose to cardiovascular disease risk.

Autonomic Neuropathy-a Prospective Cohort Study of Symptoms and E/I Ratio in Normal Glucose Tolerance, Impaired Glucose Tolerance, and Type 2 Diabetes

Background

Autonomic neuropathy in diabetes, in addition to causing a range of symptoms originating from the autonomic nervous system, may increase cardiovascular morbidity. Our aim was to study the progression of autonomic neuropathy, based on symptom score and evaluation of an autonomic test, in persons with normal and impaired glucose tolerance and in patients with type 2 diabetes (T2D).

Methods

Participants were recruited in 2003/2004 with a follow-up in 2014. The participants’ glucose tolerance was categorized using oral glucose tolerance tests. Symptoms were evaluated using an autonomic symptom score (ASS), ECG was used to test cardiac autonomic function based on the expiration/inspiration ratio (E/I ratio), and blood samples were taken on both occasions.

Results

ASSs were higher at follow-up in the T2D patients than in the normal glucose tolerance group (mean 1.21 ± 1.30 vs. 0.79 ± 0.7; p < 0.05). E/I ratio did not deteriorate more than could be expected as an aging effect in well-controlled T2D. No relationship was found between E/I ratio and HbA1c or ASS.

Conclusion

The presence of autonomic symptoms increased over time in T2D patients, but the symptoms did not correlate with the E/I ratio in this metabolically well-controlled cohort. ASSs can be a useful clinical tool when assessing the progression of autonomic dysfunction in patients with abnormal glucose metabolism.

Association of sleep quality components and wake time with metabolic syndrome: The Qazvin Metabolic Diseases Study (QMDS), Iran

PURPOSE

The aim of this study was to determine the association of sleep quality and sleep quantity with metabolic syndrome in Qazvin, Iran.

METHODS

this cross sectional study was conducted in 1079 residents of Qazvin selected by multistage cluster random sampling method in 2011. Metabolic syndrome was defined according to the criteria proposed by the national cholesterol education program third Adult treatment panel. Sleep was assessed using the Pittsburgh sleep quality index (PSQI). A logistic regression analysis was used to examine the association of sleep status and metabolic syndrome.

RESULTS

Mean age was 40.08±10.33years. Of 1079, 578 (52.2%) were female, and 30.6% had metabolic syndrome. The total global PSQI score in the subjects with metabolic syndrome was significantly higher than subjects without metabolic syndrome (6.30±3.20 vs. 5.83±2.76, P=0.013). In logistic regression analysis, sleep disturbances was associated with 1.388 fold increased risk of metabolic syndrome after adjustment for age, gender, and body mass index.

CONCLUSION

Sleep disturbances component was a predictor of metabolic syndrome in the present study. More longitudinal studies are necessary to understand the association of sleep quality and its components with metabolic syndrome.

Heart rate recovery time in metabolically healthy and metabolically unhealthy obese children

BACKGROUND

Autonomic dysfunction is an emerging non-traditional cardiovascular risk factor that correlates with obesity, components of metabolic syndrome, as well as cardiorespiratory fitness. As a simple and validated index of autonomic balance, heart rate recovery (HRR) has been reported as a useful biomarker for predicting cardiovascular morbidity and mortality.

OBJECTIVES

The aim of this study was to compare HRR in metabolically healthy vs. metabolically unhealthy obese children.

METHODS

A total of 56 obese children of whom 31 had metabolic syndrome were examined. All the participants underwent the multistage submaximal cycle ergometer test and HRR was determined one minute after the test.

RESULTS

The HRR was significantly lower (18.9 ± 3.7) in a group of metabolically unhealthy obese children compared to metabolically healthy obese children (24 ± 4.1) p < 0.001. Logistic regression analysis showed that reduction in HRR was also influenced by higher BMI.

CONCLUSION

Our findings implicate the presence of the autonomic dysfunction as reflected by impaired heart rate recovery (HRR) in obese children with metabolic syndrome.

Orthostatic hypertension in normotensive type 2 diabetics: What characteristics?

AIM OF THE STUDY

We aimed to determine the prevalence of orthostatic hypertension (OHT) in normotensive, newly diagnosed type 2 diabetics, to assess clinical, biological characteristics of those patients and evaluate the evolution of their blood pressure, after one year of follow-up.

MATERIALS AND METHODS

It is an observational, prospective, cohort study, on 108 normotensive, newly diagnosed diabetics, 40 men and 68 women aged from 40 to 70 ans. OHT was defined as an increase of systolic blood pressure (SBP) ≥20mmHg and/or diastolic blood pressure (DBP) ≥10mmHg, after 1 and 2min of standing from supine position. Arterial hypertension and metabolic syndrome were respectively defined according to WHO and AHA 2009 guidelines. Clinical and biological data were collected for all patients. They had a screening for diabetic complications and a follow-up during one year. Statistical analysis was performed with Epi-Info 6.04.

RESULTS

We found OHT in 22 patients (20.4%). Patients with OHT had a higher SBP at lying position (P=0.029), a higher waist circumference (P=0.022) and LDL (P=0.041). They had more frequently obesity (P=0.036) left ventricular hypertrophy (P=0.024), metabolic syndrome (P=0.042) and cerebrovascular events (P=0.050) when compared with those with normal blood pressure response to orthostasis. One year after follow-up, the prevalence of permanent hypertension was significantly higher in the OHT group (P=0.0008).

CONCLUSION

Our study suggests that OHT is associated with insulin resistance syndrome and onset of sustained arterial hypertension in normotensive, newly diagnosed diabetics.

Excessive consumption of fructose causes cardiometabolic dysfunctions through oxidative stress and inflammation

A rapid rise in obesity, as well as physical inactivity, in industrialized countries is associated with fructose-consumption-mediated metabolic syndrome having a strong association with cardiovascular disease. Although insulin resistance is thought to be at the core, visceral obesity, hypertension, and hypertriglyceridemia are also considered important components of this metabolic disorder. In addition, various other abnormalities such as inflammation, oxidative stress, and elevated levels of uric acid are also part of this syndrome. Lifestyle changes through improved physical activity, as well as nutrition, are important approaches to minimize metabolic syndrome and its deleterious effects.

Cerebral Microvascular Dysfunction and Inflammation Are Improved by Centrally Acting Antihypertensive Drugs in Metabolic Syndrome

BACKGROUND

We aimed to investigate the effects of chronic oral treatment with centrally acting antihypertensive drugs, such as clonidine (CLO), an α₂-adrenoceptor agonist, or LNP599, a selective I₁ imidazoline receptor agonist, on brain microvascular function in rats with high-fat diet (HFD)-induced metabolic syndrome.

METHODS

Male Wistar Kyoto rats were maintained on a normal diet (CON) or a HFD for 20 weeks. After this period, the HFD group received oral CLO (0.1 mg/kg), LNP599 (20 mg/kg), or vehicle daily for 4 weeks. Systolic blood pressure and heart rate (HR) were evaluated by photoplethysmography. Functional capillary density, endothelial function, and endothelial-leukocyte interactions in the brain were investigated by intravital video microscopy. Cerebral microcirculatory flow was evaluated by laser speckle contrast imaging. Brain tissue endothelial nitric oxide synthase, oxidative enzyme, and inflammatory marker expression levels were analyzed.

RESULTS

Metabolic syndrome decreased brain functional capillary density and microvascular blood perfusion, changes accompanied by deficient brain microcirculation vasodilatory responses to acetylcholine. Significant numbers of rolling and adherent leukocytes were also observed in the brain venules. Chronic sympathetic inhibition with clonidine and LNP599 reduced blood pressure and HR. These effects were accompanied by reversals of cerebral capillary rarefaction, improvements in cerebral microvascular blood flow and endothelial function, and decreases in endothelial-leukocyte interactions in the cerebral venules.

CONCLUSIONS

Our results suggest that central sympathetic inhibition exerts beneficial effects by increasing perfusion and reducing inflammatory marker expression and oxidative stress in the brains of rats with metabolic syndrome. Centrally acting antihypertensive drugs may be helpful in regulating cerebral microcirculatory function and vascular inflammation in metabolic syndrome.

Acoustic Measures of Voice and Physiologic Measures of Autonomic Arousal during Speech as a Function of Cognitive Load

OBJECTIVES/HYPOTHESIS

This study aimed to determine the relationship among cognitive load condition and measures of autonomic arousal and voice production in healthy adults.

STUDY DESIGN

A prospective study design was conducted.

METHODS

Sixteen healthy young adults (eight men, eight women) produced a sentence containing an embedded Stroop task in each of two cognitive load conditions: congruent and incongruent. In both conditions, participants said the font color of the color words instead of the word text. In the incongruent condition, font color differed from the word text, creating an increase in cognitive load relative to the congruent condition in which font color and word text matched. Three physiologic measures of autonomic arousal (pulse volume amplitude, pulse period, and skin conductance response amplitude) and four acoustic measures of voice (sound pressure level, fundamental frequency, cepstral peak prominence, and low-to-high spectral energy ratio) were analyzed for eight sentence productions in each cognitive load condition per participant.

RESULTS

A logistic regression model was constructed to predict the cognitive load condition (congruent or incongruent) using subject as a categorical predictor and the three autonomic measures and four acoustic measures as continuous predictors. It revealed that skin conductance response amplitude, cepstral peak prominence, and low-to-high spectral energy ratio were significantly associated with cognitive load condition.

CONCLUSIONS

During speech produced under increased cognitive load, healthy young adults show changes in physiologic markers of heightened autonomic arousal and acoustic measures of voice quality. Future work is necessary to examine these measures in older adults and individuals with voice disorders.

Double product break point estimates ventilatory threshold in individuals with type 2 diabetes

[Purpose] To verify the identification of the anaerobic threshold through the double product breakpoint (DPBP) method for individuals with type 2 diabetes. [Subjects and Methods] Nine individuals with T2D (7 females; age=63.2 ± 8.9 y) and 10 non-diabetic (ND) (7 females; age=58.3 ± 7.8 y) performed an incremental exercise test on a cycle ergometer. Heart rate (HR), blood pressure (BP) and expired gas were measured at the end of each stage. The ventilatory threshold (VT) and DPBP were considered as the exercise intensities above which an over proportional increases in VE and DP were observed in relation to increasing workload. [Results] No differences were observed between the workloads, HR and VO2 corresponding to the AT identified respectively by VT and DPBP. For the T2D, strong correlations between VT and DBPB workloads (r=0.853), HR (r=0.714), and VO2 (r=0.863) were found. These relationships were similar to those found for the control group (r=0.923; r=0.881; and r=0.863, respectively). [Conclusion] These results demonstrate that the DPBP enables for the prediction of AT and correlated well the VT in both the T2D and ND participants.

When to eat? The influence of circadian rhythms on metabolic health: are animal studies providing the evidence?

As obesity and metabolic diseases rise, there is need to investigate physiological and behavioural aspects associated with their development. Circadian rhythms have a profound influence on metabolic processes, as they prepare the body to optimise energy use and storage. Moreover, food-related signals confer temporal order to organs involved in metabolic regulation. Therefore food intake should be synchronised with the suprachiasmatic nucleus (SCN) to elaborate efficient responses to environmental challenges. Human studies suggest that a loss of synchrony between mealtime and the SCN promotes obesity and metabolic disturbances. Animal research using different paradigms has been performed to characterise the effects of timing of food intake on metabolic profiles. Therefore the purpose of the present review is to critically examine the evidence of animal studies, to provide a state of the art on metabolic findings and to assess whether the paradigms used in rodent models give the evidence to support a 'best time' for food intake. First we analyse and compare the current findings of studies where mealtime has been shifted out of phase from the light-dark cycle. Then, we analyse studies restricting meal times to different moments within the active period. So far animal studies correlate well with human studies, demonstrating that restricting food intake to the active phase limits metabolic disturbances produced by high-energy diets and that eating during the inactive/sleep phase leads to a worse metabolic outcome. Based on the latter we discuss the missing elements and possible mechanisms leading to the metabolic consequences, as these are still lacking.

Association of glucose homeostasis measures with heart rate variability among Hispanic/Latino adults without diabetes: the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

BACKGROUND

Reduced heart rate variability (HRV), a measure of cardiac autonomic function, is associated with an increased risk of cardiovascular disease (CVD) and mortality. Glucose homeostasis measures are associated with reduced cardiac autonomic function among those with diabetes, but inconsistent associations have been reported among those without diabetes. This study aimed to examine the association of glucose homeostasis measures with cardiac autonomic function among diverse Hispanic/Latino adults without diabetes.

METHODS

The Hispanic community Health Study/Study of Latinos (HCHS/SOL; 2008-2011) used two-stage area probability sampling of households to enroll 16,415 self-identified Hispanics/Latinos aged 18-74 years from four USA communities. Resting, standard 12-lead electrocardiogram recordings were used to estimate the following ultrashort-term measures of HRV: RR interval (RR), standard deviation of all normal to normal RR (SDNN) and root mean square of successive differences in RR intervals (RMSSD). Multivariable regression analysis was used to estimate associations between glucose homeostasis measures with HRV using data from 11,994 adults without diabetes (mean age 39 years; 52 % women).

RESULTS

Higher fasting glucose was associated with lower RR, SDNN, and RMSSD. Fasting insulin and the homeostasis model assessment of insulin resistance was negatively associated with RR, SDNN, and RMSSD, and the association was stronger among men compared with women. RMSSD was, on average, 26 % lower in men with higher fasting insulin and 29 % lower in men with lower insulin resistance; for women, the corresponding estimates were smaller at 4 and 9 %, respectively. Higher glycated hemoglobin was associated with lower RR, SDNN, and RMSSD in those with abdominal adiposity, defined by sex-specific cut-points for waist circumference, after adjusting for demographics and medication use. There were no associations between glycated hemoglobin and HRV measures among those without abdominal adiposity.

CONCLUSIONS

Impairment in glucose homeostasis was associated with lower HRV in Hispanic/Latino adults without diabetes, most prominently in men and individuals with abdominal adiposity. These results suggest that reduced cardiac autonomic function is associated with metabolic impairments before onset of overt diabetes in certain subgroups, offering clues for the pathophysiologic processes involved as well as opportunity for identification of those at high risk before autonomic control is manifestly impaired.

Elevated circulating level of a cytokine, pancreatic-derived factor, is associated with metabolic syndrome components in a Chinese population

Aims/Introduction

Pancreatic‐derived factor (PANDER) is an important factor involved in obesity, glucose intolerance and abnormal lipid metabolism in animals. Nevertheless, the relationship between PANDER and metabolic syndrome (MetS) in humans has not yet been reported.

Materials and Methods

To determinate the relationship between PANDER and MetS components, 212 individuals aged between 40 and 65 years were recruited. Fasting plasma PANDER and other variables were measured. Correlations of plasma PANDER and other variables were carried out. Plasma PANDER level was compared in participants with no metabolic components and those with any metabolic components, as well as in normal glucose tolerance, impaired glucose tolerance and diabetes mellitus participants.

Results

In all the participants, there were 65 participants in the no metabolic components group and 147 participants in the any metabolic components group. Plasma PANDER level was increased with the number of MetS components (P < 0.05) and correlated with metabolic score (r = 0. 529, P < 0.001). In addition, plasma PANDER significantly correlated with fasting plasma glucose (r = 0.187, P = 0.046), 2‐h plasma glucose (r = 0.195, P = 0.035), homeostasis model assessment of β‐cell function (r = −0.191, P = 0.039), triglyceride (r = 0.305, P = 0.001) and high‐density lipoprotein cholesterol (r = −0.333, P < 0.001). Using multivariable logistic regression analysis, circulating PANDER was associated with an increased risk ratio of impaired glucose tolerance or diabetes mellitus (odds ratio 2.22, 95% confidence interval 1.15–4.42, P = 0.018) after adjustment of the other possible confounders.

Conclusions

Circulating level of PANDER in relation to the accumulation in MetS suggested that persons with elevated levels of PANDER were associated with an increased risk of metabolic syndrome.

Cardiac Autonomic Nervous System Activation and Metabolic Profile in Young Children: The ABCD Study

Background

In adults, increased sympathetic and decreased parasympathetic nervous system activity are associated with a less favorable metabolic profile. Whether this is already determined at early age is unknown. Therefore, we aimed to assess the association between autonomic nervous system activation and metabolic profile and its components in children at age of 5–6 years.

Methods

Cross-sectional data from an apparently healthy population (within the ABCD study) were collected at age 5–6 years in 1540 children. Heart rate (HR), respiratory sinus arrhythmia (RSA; parasympathetic activity) and pre-ejection period (PEP; sympathetic activity) were assessed during rest. Metabolic components were waist-height ratio (WHtR), systolic blood pressure (SBP), fasting triglycerides, glucose and HDL-cholesterol. Individual components, as well as a cumulative metabolic score, were analyzed.

Results

In analysis adjusted for child’s physical activity, sleep, anxiety score and other potential confounders, increased HR and decreased RSA were associated with higher WHtR (P< 0.01), higher SBP (p<0.001) and a higher cumulative metabolic score (HR: p < 0.001; RSA: p < 0.01). Lower PEP was only associated with higher SBP (p <0.05). Of all children, 5.6% had 3 or more (out of 5) adverse metabolic components; only higher HR was associated with this risk (per 10 bpm increase: OR = 1.56; p < 0.001).

Conclusions

This study shows that decreased parasympathetic activity is associated with central adiposity and higher SBP, indicative of increased metabolic risk, already at age 5–6 years.

Association of Sleep Quality and Waking Time with Prediabetes: The Qazvin Metabolic Diseases Study, Iran

Aims. It is known that sleep has a major role in the regulation of endocrine functions and glucose metabolism. However, it is not clear whether the sleep pattern is affected at or prior to the onset of diabetes, among those with prediabetes. The purpose of this study was to determine the association of sleep patterns and prediabetes in Qazvin, Iran. Methods. A representative sample of residents of Qazvin was selected by multistage cluster random sampling method in 2011. Plasma glucose level and sleep quality were measured cross-sectionally as well as demographic characteristics. A logistic regression analysis was used to examine the association of sleep status and prediabetes. Results. Mean age was 39.3 ± 10.1 years. Of 958, 474 (49.47%) were female. Poor sleep quality was associated with 2.197-fold increased risk of prediabetes after adjustment for age, gender, body mass index, and metabolic syndrome. Conclusion. This study provides evidences that subjects with poor sleep quality are more likely to develop prediabetes than people with good sleep quality.

Personality Correlates of Midlife Cardiometabolic Risk: The Explanatory Role of Higher-Order Factors of the Five-Factor Model

Varying associations are reported between Five-Factor Model (FFM) personality traits and cardiovascular disease risk. Here, we further examine dispositional correlates of cardiometabolic risk within a hierarchical model of personality that proposes higher-order traits of Stability (shared variance of Agreeableness, Conscientiousness, inverse Neuroticism) and Plasticity (Extraversion, Openness), and we test hypothesized mediation via biological and behavioral factors. In an observational study of 856 community volunteers aged 30-54 years (46% male, 86% Caucasian), latent variable FFM traits (using multiple-informant reports) and aggregated cardiometabolic risk (indicators: insulin resistance, dyslipidemia, blood pressure, adiposity) were estimated using confirmatory factor analysis (CFA). The cardiometabolic factor was regressed on each personality factor or higher-order trait. Cross-sectional indirect effects via systemic inflammation, cardiac autonomic control, and physical activity were tested. CFA models confirmed the Stability "meta-trait," but not Plasticity. Lower Stability was associated with heightened cardiometabolic risk. This association was accounted for by inflammation, autonomic function, and physical activity. Among FFM traits, only Openness was associated with risk over and above Stability, and, unlike Stability, this relationship was unexplained by the intervening variables. A Stability meta-trait covaries with midlife cardiometabolic risk, and this association is accounted for by three candidate biological and behavioral factors.

Cardiovascular autonomic tone relation to metabolic parameters and hsCRP in normoglycemia and prediabetes

AIMS

The aim of the study was to evaluate cardiovascular autonomic function (CAF) at different stages of obesity and in the presence of metabolic syndrome (MetS), and its association with metabolic parameters and hsCRP in subjects with normal glucose tolerance (NGT) and prediabetes.

METHODS

A total of 259 subjects (mean age 47.1 ± 14.6 years, mean BMI 31.4 ± 8.1 kg/m(2)), divided in 2 groups: NGT and prediabetes, and subdivided according to glucose tolerance, BMI and MetS, were enrolled. Anthropometric indices, glucose tolerance, blood pressure, serum lipids and hsCRP were measured. Body composition was estimated by impedance analysis. CAF was assessed by ANX-3.0 method.

RESULTS

Sympathetic and parasympathetic activity were decreased in severe obesity and MetS as compared to controls in NGT. Negative correlation was observed between sympathetic and parasympathetic tone and BMI, waist circumference, total body fat, visceral fat area (VFA), blood pressure, total and LDL cholesterol, and hsCRP in NGT; and VFA, HbA1c and glycemia in prediabetes.

CONCLUSION

Obesity and MetS seem to be associated with CAF deterioration, and metabolic parameters and hsCRP correlate with CAF and probably increase cardiovascular risk in NGT, whilst VFA, HbA1c and glycemia significantly influence CAF alterations in prediabetes.

Heart rate variability, adiposity, and physical activity in prepubescent children

PURPOSE

This study aimed at examining the associations between weight status, body fat mass, and heart rate variability in prepubescent children, adjusting for physical activity levels.

METHODS

A cross-sectional investigation in which a total of 50 Caucasian pre-pubertal children (21 normal weight; 8 overweight; 21 obese), aged 6-10 years (8.33 ± 1.14), including both boys (n = 24) and girls (n = 26), were recruited from local schools. Total body fat and trunk fat were evaluated through dual-energy X-ray absorptiometry. Free-living physical activity levels were evaluated by accelerometer. Short-term heart rate variability acquisition was performed; time- and frequency-domain parameters were analysed. Logarithmic transformations of the low-frequency (LnLFnu), high-frequency (LnHFnu) normalized units and low-frequency/high-frequency (LnLFnu/HFnu) ratio were computed.

RESULTS

Adjusting for age, Tanner stage, and moderate to vigorous physical activity levels, obese children compared to normal weight children showed a significant decreased LnHfnu (3.8 ± 0.2 vs 4.1 ± 0.2 %) and both higher LnLFnu (4.0 ± 0.4 vs 3.7 ± 0.3 %) and LnLFnu/LnHFnu ratio (1.1 ± 0.1 vs 0.9 ± 0.1). LnHFnu showed significant negative correlation with waist circumference (r = -0.598; P = 0.000), total body fat (r = -0.409; P = 0.011) and trunk fat (r = -0.472; P = 0.003). Both LnLFnu and LnLFnu/LnHFnu ratio showed positive correlations with waist circumference (r = 0.455; r = 0.513) and trunk fat (r = 0.370; r = 0.415).

CONCLUSIONS

A higher amount of body fat mass, particularly central fat, was shown to be related to decreased parasympathetic modulation in time-domain heart rate variability. This finding highlights the potential cardiovascular risk that excessive fat mass may represent even at very young age.

Heart rate variability and the metabolic syndrome: a systematic review of the literature

BACKGROUND

A number of cross-sectional studies have examined associations between heart rate variability and metabolic syndrome, but differences in study populations, data collection and analysis methodologies make synthesis difficult. The purpose of this study was to systematically review published primary research examining associations between heart rate variability and metabolic syndrome or its individual risk factors.

METHODS

A systematic literature search of PubMed and EMBASE was conducted to identify relevant articles published from January 1999 to December 2012. Studies were included if they examined associations between heart rate variability analysed by standard protocols and metabolic syndrome risk factors according to published definitions. All papers were scored with a modified Downs and Black instrument, and data were extracted.

RESULTS

Fourteen studies were included. Heart rate variability generally was reduced in women with metabolic syndrome compared to those without, while results in men were inconsistent. Time and frequency domain heart rate variability parameters were associated with individual metabolic syndrome risk factors, though sex differences exist. Only two studies considered nonlinear and Poincaré plot heart rate variability parameters, which were reduced in metabolic syndrome.

CONCLUSIONS

Heart rate variability is altered differently in men and women with metabolic syndrome. Future studies should follow consistent heart rate variability analysis protocols and metabolic syndrome definitions and include more comprehensive analyses to investigate potential mechanisms.

Improvement of heart rate variability after decreased insulin resistance after sleeve gastrectomy for morbidly obesity patients

BACKGROUND

Morbidly obese patients display both an autonomic nervous imbalance and impaired glucose metabolism, and both of these conditions can be partially reversed after bariatric surgery. The aim of the present study was to investigate changes in heart rate variability (HRV) and glucose metabolism in patients after laparoscopic sleeve gastrectomy (SG).

METHODS

Eighteen morbidly obese patients who underwent SG were examined before surgery and at 7, 30, 90, and 180 days after surgery. Indices of HRV included time-domain, frequency-domain, and nonlinear parameters. Glucose metabolism was evaluated by the measuring levels of insulin resistance, glycated hemoglobin (HbA(1c)), and gut hormones.

RESULTS

The study included 9 men and 9 women with a mean age of 34 years. In the HRV study, the average R-R interval, median R-R interval, standard deviation of the R-R intervals, root mean squared successive difference of the R-R intervals (RMSSD), and the number of pairs of successive normal-to-normal beat intervals that differed by>50 ms significantly increased at 180 days after surgery. Regarding the frequency-domain indices, the low frequency (LF)/high frequency (HF) ratio was more balanced at 90 days after SG compared with baseline, and increases in the total power, LF band, and HF band were observed at 180 days. The assessments of insulin resistance, glucose metabolism, and gut hormones revealed not only improvements in the homeostasis model assessment of insulin resistance and HbA1c levels but also increases in the levels of glucagon-like peptide-1 at 90 and 180 days after surgery compared with baseline. A multivariable regression model revealed significantly negative associations between the perioperative changes in HOMA-IR and changes in both the RMSSD and HF band.

CONCLUSIONS

SG leads to early improvements in insulin resistance and glucose metabolism that are followed by improvements in HRV indices. Improvements in insulin resistance were associated with increases in the RMSSD and HF band index, but the mechanism of these changes require further study.

Resting heart rate as a marker for identifying the risk of undiagnosed type 2 diabetes mellitus: a cross-sectional survey

Background

Fast resting heart rate might increase the risk of developing type 2 diabetes mellitus (T2DM). However, it is unclear whether resting heart rate could be used to predict the risk of undiagnosed T2DM. Therefore, the purposes of this study were to examine the association between resting heart rate and undiagnosed T2DM, and evaluate the feasibility of using resting heart rate as a marker for identifying the risk of undiagnosed T2DM.

Methods

A cross-sectional survey was conducted. Resting heart rate and relevant covariates were collected and measured. Fasting blood samples were obtained to measure blood glucose using the modified hexokinase enzymatic method. Predictive performance was analyzed by Receiver Operating Characteristic (ROC) curve.

Results

This study included 16, 636 subjects from rural communities aged 35–78 years. Resting heart rate was significantly associated with undiagnosed T2DM in both genders. For resting heart rate categories of <60, 60–69, 70–79, and ≥80 beats/min, adjusted odds ratios for undiagnosed T2DM were 1.04, 2.32, 3.66 and 1.05, 1.57, 2.98 in male and female subjects, respectively. For male subjects, resting heart rate ≥70 beats/min could predict undiagnosed T2DM with 76.56% sensitivity and 48.64% specificity. For female subjects, the optimum cut-off point was ≥79 beats/min with 49.72% sensitivity and 67.53% specificity. The area under the ROC curve for predicting undiagnosed T2DM was 0.65 (95% CI: 0.64-0.66) and 0.61(95% CI: 0.60-0.62) in male and female subjects, respectively.

Conclusions

Fast resting heart rate is associated with an increased risk of undiagnosed T2DM in male and female subjects. However, resting heart rate as a marker has limited potential for screening those at high risk of undiagnosed T2DM in adults living in rural areas.

Role of Nitric Oxide Synthase Uncoupling at Rostral Ventrolateral Medulla in Redox-Sensitive Hypertension Associated With Metabolic Syndrome

Metabolic syndrome (MetS), which is rapidly becoming prevalent worldwide, is long known to be associated with hypertension and recently with oxidative stress. Of note is that oxidative stress in the rostral ventrolateral medulla (RVLM), where sympathetic premotor neurons reside, contributes to sympathoexcitation and hypertension. This study sought to identify the source of tissue oxidative stress in RVLM and their roles in neural mechanism of hypertension associated with MetS. Adult normotensive rats subjected to a high-fructose diet for 8 weeks developed metabolic traits of MetS, alongside increases in sympathetic vasomotor activity and blood pressure. In RVLM of these MetS rats, the tissue level of reactive oxygen species was increased, nitric oxide (NO) was decreased, and mitochondrial electron transport capacity was reduced. Whereas the protein expression of neuronal NO synthase (nNOS) or protein inhibitor of nNOS was increased, the ratio of nNOS dimer/monomer was significantly decreased. Oral intake of pioglitazone or intracisternal infusion of tempol or coenzyme Q 10 significantly abrogated all those molecular events in high-fructose diet–fed rats and ameliorated sympathoexcitation and hypertension. Gene silencing of protein inhibitor of nNOS mRNA in RVLM using lentivirus carrying small hairpin RNA inhibited protein inhibitor of nNOS expression, increased the ratio of nNOS dimer/monomer, restored NO content, and alleviated oxidative stress in RVLM of high-fructose diet–fed rats, alongside significantly reduced sympathoexcitation and hypertension. These results suggest that redox-sensitive and protein inhibitor of nNOS–mediated nNOS uncoupling is engaged in a vicious cycle that sustains the production of reactive oxygen species in RVLM, resulting in sympathoexcitation and hypertension associated with MetS.

Interactions between sleep, circadian function, and glucose metabolism: implications for risk and severity of diabetes

Sleep disturbances, including sleep insufficiency and sleep fragmentation, have been linked to abnormal glucose metabolism and increased diabetes risk. Well-controlled laboratory studies have provided insights regarding the underlying mechanisms. Several large prospective studies suggest that these sleep disturbances are associated with an increased risk of incident diabetes. Obstructive sleep apnea, which combines sleep fragmentation and hypoxemia, is a major risk factor for insulin resistance and possibly diabetes. Whether glycemic control in type 2 diabetes patients can be improved by treating sleep apnea remains controversial. Recently, sleep disturbances during pregnancy and their relationship to gestational diabetes and hyperglycemia have received considerable attention owing to potential adverse effects on maternal and fetal health. Additionally, evidence from animal models has identified disruption of the circadian system as a putative risk factor for adverse metabolic outcomes. The purpose of this review is to provide an update on the current state of knowledge linking sleep disturbances, circadian dysfunction, and glucose metabolism. Experimental, prospective, and interventional studies are discussed.

Association of EZSCAN values with arterial stiffness in individuals without diabetes or cardiovascular disease

Background

The EZSCAN test was recently developed to screen for early dysglycemia through an assessment of sudomotor function. Given the associations of dysglycemia and autonomic dysfunction with the development of arterial stiffness, EZSCAN may also detect early arterial stiffness. The aim of this study was to investigate the association of EZSCAN with arterial stiffness across blood glucose levels.

Methodology and Principal Findings

A total of 5532 participants without diabetes or established cardiovascular disease were evaluated with EZSCAN. Their central systolic blood pressure (cSBP), brachial-ankle pulse wave velocity (baPWV), and ankle-brachial index (ABI) were also measured. Multivariate linear regression analyses were used to assess the association between the EZSCAN value and the cSBP, baPWV, and ABI measurements in all of the participants, with additional subgroup analysis that separated participants into a normal glucose tolerance (NGT) group and an impaired glucose regulation (IGR) group. The frequency of the IGRs increased with quartiles of the EZSCAN value (P for trend <0.0001). The levels of cSBP and baPWV increased while the levels of ABI decreased across quartiles of EZSCAN value in both NGT and IGR individuals (P for trend <0.0001 for all). In multivariable analyses, the EZSCAN value was positively associated with cSBP (log-transformed beta = 8.20, P<0.0001) and baPWV (log-transformed beta = 1.82, P<0.0001) but inversely associated with ABI (log-transformed beta = −0.043, P<0.0001) and was independent of conventional factors. Further adjustment for fasting and postprandial glucoses did not attenuate the associations. The results were also unchanged when stratified by IGR.

Conclusions and Significance

The EZSCAN results were associated with arterial stiffness independent of conventional factors, blood glucose levels, and glucose tolerance status, suggesting a probable link between the EZSCAN value and arterial stiffness through autonomic dysfunction. The EZSCAN test may help us detect the development of arterial stiffness in high risk individuals to prevent unfavorable cardiovascular events.

The effects of dietary weight loss on indices of norepinephrine turnover: modulatory influence of hyperinsulinemia

OBJECTIVES

This study was conducted to examine (1) the effects of dietary weight loss on indices of norepinephrine (NE) turnover and (2) whether baseline hyperinsulinemia modulates sympathetic neural adaptations.

METHODS

Obese individuals aged 56 ± 1 year, BMI 32.5 ± 0.4 kg/m(2) , with metabolic syndrome, underwent a 12-week hypocaloric diet (HCD, n = 39) or no treatment (n = 26). Neurochemical measurements comprised arterial dihydroxyphenylalanine (DOPA), 3,4-dihydroxyphenylglycol (DHPG), and NE concentrations, the steady-state ratio of [3H]-DHPG to [3H]-NE, as an index of neuronal uptake, and calculated whole-body plasma NE clearance and spillover rates.

RESULTS

Body weight decreased by -7.4 ± 0.5% in HCD group (P < 0.001) and was accompanied by reductions in DOPA, NE, and DHPG averaging -14 ± 5% (P = 0.001), -23 ± 4% (P <0.001), and -5 ± 4% (P = 0.03), respectively. NE spillover rate decreased by -88 ± 39 ng/min (P = 0.01), whereas neuronal uptake and NE plasma clearance were unchanged. Despite similar weight loss, hyperinsulinemic subjects exhibited greater reductions in NE and NE spillover rate, compared to normoinsulinemic subjects (group by time interaction P < 0.05).

CONCLUSIONS

Weight loss is associated with down-regulation of sympathetic nervous activity but no overall alteration in disposition indices. Hyperinsulinemic subjects derive a greater sympathoinhibitory benefit during weight loss.