GABAergic neuronal ontogeny in the central nervous system of the viviparous teleost Poecilia sphenops.

Systematic review of cardiovascular intervention studies in women after Preeclampsia.

Vagally-mediated heart rate variability during an emotionally arousing paradigm in adolescents with major depressive disorder.

Design and rationale of RECOVER-AUTONOMIC: A randomized platform trial evaluating interventions for Long COVID postural orthostatic tachycardia syndrome.

Real-time feedback-based personalized moderate-intensity aerobic brisk walking intervention using wrist-worn photoplethysmography (PPG) on mild-to-moderate depressive.

Postoperative patients with complex congenital heart disease (CHD), such as those who have undergone Fontan procedures or Tetralogy of Fallot (TOF) repairs, often experience complications, including arrhythmias and heart failure. Heart rate variability (HRV) analysis assesses autonomic function and predicts cardiac outcomes; however, conventional linear methods have limitations, particularly in pediatric populations with variable heart rates. Nonlinear HRV analysis offers a robust alternative. This study evaluated the utility of nonlinear HRV indices to identify early autonomic dysfunction in postoperative patients with CHD. A total of 41 postoperative patients with CHD (22 Fontan, 19 TOF) and 34 age-matched healthy controls underwent 24-h electrocardiogram recordings during sleep. Frequency- and time-domain HRV indices were calculated, alongside nonlinear measures such as Poincaré plot analysis and Higuchi fractal dimension (HFD). Statistical analyses compared the groups and assessed correlations between HRV indices and clinical parameters. Patients who underwent TOF repairs exhibited significantly lower low frequency, high frequency, standard deviation of all normal R-R intervals, and the root mean square of successive differences between R-R intervals values than those in the control group. Nonlinear indices, particularly HFD, were unaffected by heart rate, enhancing reliability in pediatric populations. Age-related declines in fractal indices in postoperative patients with TOF repairs suggest progressive autonomic dysfunction. Nonlinear HRV analysis offers valuable insights into autonomic dysregulation in postoperative patients with CHD, surpassing conventional methods in reliability. These approaches may enable early detection of autonomic deterioration, improving risk stratification and guiding management. Further validation in larger cohorts is warranted.

Heart rate variability (HRV) reflects cardiac autonomic function and cardiovascular health. While electrocardiography (ECG) remains the gold standard for HRV assessment, photoplethysmography (PPG)-based wearables offer an alternative for monitoring. This study aimed to validate the wrist-worn PPG device Bora band® for short-term HRV assessment against standard ECG and to characterize domain-specific agreement patterns. In this prospective, single-center observational study, 66 participants in sinus rhythm underwent simultaneous high-resolution 12-lead ECG and wrist-based PPG recording for 5min and 30s. PPG-derived interbeat intervals were extracted and compared to ECG-derived R-R intervals. Sixteen HRV metrics from time-, frequency-, and non-linear domains were computed for both modalities. Agreement was assessed using biweight mid-correlation (ρ), Cliff's delta (δ), and equivalence testing (TOST). Strong agreement was observed for mean heart rate (ρ = 1.0, δ = 0.104, TOST p < 0.001), standard deviation of normal-to-normal intervals (ρ = 0.98, δ = 0.037, TOST p = 0.003), deceleration capacity of heart rate (ρ = 0.95, δ = 0.071, TOST p = 0.014), coefficient of variation of normal-to-normal intervals (ρ = 0.98, δ = 0.035, TOST p = 0.002) and Poincaré Plot standard deviation 2 (ρ = 0.99, δ = 0.074, TOST p < 0.001). Moderate agreement was noted for long-term fractal scaling exponent and very low-, low- and high-frequency power. Weaker agreement appeared for short-term variability and entropy metrics. Bland-Altman analysis indicated minimal bias without systematic error. Under controlled resting conditions, wrist-based PPG provides reliable HRV indices compared with ECG-derived HRV. These findings support the use of selected PPG-derived HRV parameters for short-term assessment in clinical settings. Further validation in real-world settings will be necessary.

Diabetic peripheral neuropathy (DPN) is a length-dependent, symmetric sensorimotor polyneuropathy with substantial global and regional burden. Current pharmacologic options are largely symptomatic and do not modify disease. Lymphovenous bypass (LVB), a supermicrosurgical procedure established for lymphedema, may modulate lymphatic-immune-microvascular dysfunction relevant to DPN. The primary objective is to determine whether LVB combined with standard of care (SOC) improves small-fiber and autonomic function compared with SOC alone at 6 months. Secondary objectives are to evaluate the effects of LVB on large-fiber function, neuropathic pain, ulcer healing, quality of life, and relevant biomarkers, as well as to characterize its safety profile. SPIRIT-aligned, single-center, randomized, controlled, parallel-group superiority trial with 2:1 allocation (LVB+SOC:SOC). Randomization is stratified based on the presence or absence of active diabetic foot ulcers-defined by IWGDF and IDSA criteria. Sixty adults aged 20-80 years with confirmed DPN will be enrolled. LVB involves lymphatic-venous anastomosis to venules ≤0.8 mm. SOC consists of guideline-based glycemic and risk-factor management, pain control, and standardized wound care. Outcome assessors and statisticians are blinded. The primary outcomes are the changes in clinical neuropathy burden and pain severity at 6 and 12 months. Secondary outcomes comprise objective measures of somatic and autonomic physiology, alongside histopathological nerve fiber density, biological serum markers, and longitudinal ulcer epithelialization parameters. Data analysis will utilize a mixed-effects model for repeated measures (MMRM) with N = 60 providing 80% power to detect a conservative between-group effect size of Cohen's d ≈ 0.70. Recruitment commenced in February 2026 and is planned to continue through July 31, 2027; follow-up through July 31, 2028. As of May 2026, the first participant has been treated, and a second is scheduled. Data analysis and reporting are anticipated between late 2027 and early 2028. No outcome data are included. This trial tests a mechanism-based, non-pharmacologic adjunct targeting lymphatic-immune-microvascular dysfunction in DPN. If effective, LVB could inform phenotype-directed treatment algorithms and motivate multicenter evaluation and health-economic analyses. Nct07126197.

Chemotherapy-induced peripheral neuropathy: Mechanisms of toxicity and potential natural compounds-based therapeutics.

Objective: To explore the correlation between anxiety and the vasovagal syncope (VVS) in children and the impact of anxiety on the autonomic nervous function in pediatric VVS patients. Methods: A cross-sectional study was conducted. From January 2022 to October 2024, a total of 81 children diagnosed with VVS by head-up tilt test (HUTT) from the Department of Pediatric Cardiology, Capital Center for Children's Health, Capital Medical University were retrospectively enrolled. The VVS symptoms were quantified. The emotional state was evaluated using the screen for child anxiety related emotional disorders (SCARED). Autonomic nervous function was evaluated by the heart rate variability (HRV). According to the HUTT results, VVS children were categorized into vasoinhibitory type (VVS-VI), cardioinhibitory type (VVS-CI) and mixed type (VVS-M). The anxiety scores of VVS children were evaluated and the differences in anxiety scores among different subtypes were analyzed. According to the SCARED results, VVS children were divided into anxiety group and non-anxiety group. General characteristics, VVS symptoms scores, and HRV indicators were compared between the two groups. The comparison between groups was performed using independent sample t test, Mann-Whitney U test, Kruskal-Wallis H test, and chi-square test. Correlation analysis was completed using Spearman correlation analysis. Results: Among 81 VVS children, there were 31 males and 50 females, with the age of (11.6±2.0) years. The scores of somatization or panic, generalized anxiety disorder, separation anxiety disorder, social phobia, school phobia and the total score of anxiety in VVS children were 5.0 (2.0, 10.0), 5.0 (2.0, 9.0), 4.0 (2.0, 7.0), 5.0 (3.0, 8.0), 1.0 (0, 3.0) and 22.0 (13.0, 38.0). There were 40 cases of anxiety, accounting for 49% and 41 cases without anxiety, accounting for 51%. There was a significant difference in separation anxiety between VVS subgroups (P<0.05). Compared with the non-anxiety group, the anxiety group had a lower score of syncope symptom and a higher score of palpitation symptom (both P<0.05). Anxiety was positively correlated with palpitation score (r=0.25, P=0.011). Anxiety score was negatively correlated with syncope symptom score (r=-0.26, P=0.008), and positively correlated with chest tightness and palpitation symptom score (r=0.23, 0.26, both P<0.05). For HRV indices, the anxiety group showed significantly higher values in standard deviation of all normal-to-normal intervals, standard deviation of the average sequential 5 min normal-to-normal interval means and low-frequency power compared with the non-anxiety group (all P<0.05). Conclusions: The prevalence of anxiety in children with VVS is high and its manifestations are diverse. Those with VVS and comorbid anxiety have fewer syncope episodes but more palpitations. Children with VVS and comorbid anxiety exhibit an overall enhanced autonomic nerve tension, mainly sympathetic nerve activation.

Thyroid nodules are rare in children but carry a markedly higher risk of malignancy compared to adults (20%-26% vs. 5%). Hyperfunctioning thyroid nodules are exceptionally uncommon in the pediatric population and are typically benign. We describe a rare case of a hyperfunctioning thyroid nodule in a prepubertal child that was ultimately diagnosed as an angioinvasive encapsulated follicular carcinoma, arising in the context of the WHO entity 'follicular adenoma showing papillary architecture'. In addition, we provide a comprehensive review of published pediatric cases of hyperfunctioning thyroid nodules with malignant histology. A 12-year-old boy presented with a left-sided thyroid nodule detected on ultrasound after cervical swelling. Laboratory evaluation revealed suppressed thyroid-stimulating hormone (TSH), with free thyroxine (fT4) and free triiodothyronine (fT3) within the reference range. Serial ultrasound examinations revealed a progressively enlarging mildly hypoechoic nodule, autonomously functioning on thyroid scintigraphy. Fine-needle aspiration cytology (FNAC) was classified as TIR2. Surgical excision showed a follicular-patterned neoplasm showing papillary features, focal capsular and vascular invasion and no lymph node metastases. Comprehensive molecular analysis identified a pathogenic somatic variant in the GNAS gene, whereas no alterations were detected in TSHR, BRAF, RAS genes, the TERT promoter, or DICER1. This case highlights the importance of an integrated evaluation in pediatric thyroid nodules, particularly when hyperfunction coexists with indeterminate or suspicious imaging features. Follicular-patterned thyroid neoplasms showing papillary architecture pose diagnostic challenges in children, and molecular analysis may assist risk stratification and elucidate pathogenetic mechanisms linking autonomous function and malignant transformation.

Ultrasonic vaping devices like SURGE are marketed as safer alternatives to conventional coil-based electronic cigarettes like JUUL due to their lower operating temperatures. However, their impact on cardiovascular health has not been fully characterized. Sprague-Dawley rats were exposed daily for 9weeks to aerosol generated from SURGE, JUUL, or clean air. Heart rate variability (HRV) was continuously monitored via implanted telemetry. Cardiac fibrosis was quantified using histological analysis. Temperature profiles of SURGE, JUUL, and Nautilus (a coil-based tank device) were recorded. Aerosol samples were analyzed for carbonyl compounds using high-performance liquid chromatography. Both SURGE and JUUL exposures significantly reduced HRV (high frequency and total power) compared to air. JUUL exposure significantly increased cardiac fibrosis; SURGE showed a similar mean fibrosis level but greater variability, resulting in a nonsignificant difference. SURGE devices operated at lower peak temperatures (~131°C) than JUUL (~239°C) and Nautilus (~160-170°C). Despite it having the lowest temperature, SURGE emitted higher levels of carbonyl compounds than JUUL, although still substantially lower than Nautilus. Although SURGE operates without coils and at lower temperatures than coiled vaping devices, it generates higher levels of carbonyls than some coiled devices and impairs cardiac autonomic regulation, and it can cause cardiac fibrosis comparable to JUUL although with high variability; that is, SURGE does not reliably avoid the increase in fibrosis caused by conventional e-cigarettes. These findings suggest that non-thermal mechanisms predominate in mediating cardiovascular toxicity associated with ultrasonic vaping, challenging the assumption that coil-free designs are inherently safer. Despite its lower operating temperature and coil-free design, the SURGE ultrasonic vaping device impaired cardiac autonomic function and promoted fibrosis at a mean level comparable to that of JUUL. These findings challenge claims of reduced harm from coil-less vaping technologies and suggest that non-thermal mechanisms may drive toxicity. Regulatory evaluations should consider device emissions and physiological outcomes-not just hardware features. Physicians and policymakers should be aware that coil-less systems may still pose cardiovascular risks, and marketing these devices as inherently safer may mislead users and undermine tobacco harm reduction efforts.

Pediatric obesity is a major public health concern associated with early development of metabolic syndrome (MetS) and autonomic imbalance. Wearable devices enable continuous, non-invasive monitoring of physiological signals under real-life conditions, but their use to investigate metabolic health in youth remains limited. We examined the association between wearable-derived heart rate (HR) measures and metabolic status in children with obesity, exploring the potential of wearable-based digital phenotyping to identify early markers of autonomic and metabolic dysregulation. Fifty children and adolescents with obesity (8-16 years) were recruited. Participants wore a Fitbit Charge 2 for continuous HR monitoring. HR indices, including All-day HR, Sleeping HR, Resting HR, Inactive HR, Minimum HR, and HR dip, were computed over≥5 valid days (i.e.,with≥20 h of wear time). MetS was classified using Gurka's sex-specific criteria. Logistic regression models tested associations between HR indices and MetS status, with stepwise feature selection to identify the most informative predictors. All-day and Inactive HR were significantly higher in Not-MetS participants compared with those with MetS (p<0.05). Stepwise logistic regression identified Sleeping HR (p=0.0435) and HR dip (p=0.0332) as significant predictors of MetS. Both showed inverse associations (odds ratio <1), indicating that lower Sleeping HR and a smaller nocturnal HR dip were related to higher odds ofMetS. Fitbit-derived HR metrics, particularly Sleeping HR and HR dip, are associated with metabolic status in children with obesity. Continuous wearable monitoring can support early, personalized, and preventive strategies in pediatric cardiometabolic health through digital phenotyping of autonomic function.

Traditionally recognized for its role in calcium homeostasis and bone metabolism, vitamin D is increasingly acknowledged for its broader physiological effects, particularly in cardiovascular health. One area of growing interest is its influence on cardiac autonomic function. Cardiac autonomic dysfunction, characterized by an imbalance between sympathetic and parasympathetic activity, is a well-established predictor of adverse cardiovascular outcomes. This narrative review aims to synthesize the current literature on the association between vitamin D status and cardiac autonomic function. Accumulating observational data indicate that individuals with vitamin D deficiency exhibit poorer cardiac autonomic function, reflected by reduced heart rate variability indices, compared to vitamin D-sufficient individuals. Interventional trials, though limited, suggest that vitamin D supplementation may improve autonomic balance, especially in those with baseline deficiency. The relationship appears to be affected by factors such as glycemic control, disease state, and vitamin D binding protein levels. Vitamin D may modulate autonomic regulation largely via the vitamin D receptor, which activation influences multiple downstream pathways, including central nervous system effects, neurotrophic properties, regulation of the renin-angiotensin-aldosterone system, calcium-parathyroid hormone axis, and immune modulation. However, inconsistencies in study design, population characteristics, and assessment methods limit the strength of current evidence. Further longitudinal and interventional studies are warranted to establish causality and determine whether vitamin D repletion can reduce cardiovascular risk by restoring autonomic balance.

As per the Rome IV criteria, a disorder of gut-brain interaction such as irritable bowel syndrome (IBS) is characterized by recurrent abdominal pain occurring at least 1 day per week for the previous 3 months and associated changes in bowel movements (defecation, stool frequency, or stool form). These symptoms must have begun at least 6 months prior to diagnosis. IBS affects 4% to 7% of the Indian population, with a higher prevalence observed in women and younger individuals. The present randomized controlled trial investigated the effects of a 3-month yoga intervention on IBS management. The study included 202 people (ages 18-45) diagnosed with IBS according to the Rome IV criteria. Participants were divided into a yoga intervention group (n = 102) and a control group (n = 100). Both groups underwent baseline and follow-up assessments to measure autonomic function and quality of life. The yoga group showed significant improvements in autonomic function, with reductions in resting heart rate (p < 0.0001) and the low- to high-frequency ratio of heart rate variability (p < 0.0001), as well as an increase in the Valsalva ratio (p = 0.0100). Additionally, this group experienced notable improvements in their quality of life as measured by the IBS-QOL score. Our findings suggest that yoga could be a valuable complementary therapy for IBS by enhancing autonomic regulation and improving overall well-being.

ABSTRACT Clinical Relevance Quantitative assessment of pupillary dynamics provides an objective measure of autonomic and retinal function, with potential utility in the clinical evaluation of ocular and neurological conditions. Background Increasing myopia severity may alter pupillary mechanisms, and smartphone-based pupillometry provides a non-invasive method to quantify these changes. The purpose of this study was to investigate alterations in static and dynamic pupillary parameters among emmetropes, low, moderate, and high myopia groups using smartphone-based pupillometry. Methods This comparative study included 160 participants (40 per group) aged 18–35 years. Pupillary dynamics were recorded with the Reflex Pro application under standardised illumination. Parameters analysed were latency, constriction velocity, maximum constriction speed, constriction amplitude, release amplitude, constriction time, and average pupil diameter. Intergroup differences were assessed using one-way ANOVA followed by Tukey’s post hoc analysis, with p < 0.05 considered statistically significant. Results Latency was significantly prolonged with increasing severity of myopia, ranging from 0.25 ± 0.05 s in emmetropes to 0.36 ± 0.08 s in high myopes (p < 0.001). Constriction velocity and maximum constriction speed showed progressive reduction, with high myopes exhibiting the slowest dynamics (2.9 ± 0.3 mm/s and 3.1 ± 0.3 mm/s, respectively; p < 0.001). Constriction amplitude and release amplitude also declined significantly across groups (p < 0.001). Constriction time was prolonged in high myopes (0.74 ± 0.09 s) compared to emmetropes (0.65 ± 0.08 s, p = 0.01). Average pupil diameter showed a trend towards increase in high myopes (5.8 ± 0.6 mm) but did not reach overall statistical significance (p = 0.06). Post hoc analysis confirmed that differences between emmetropes and high myopes were consistently significant for most parameters (p < 0.001). Conclusion Pupillary dynamics vary with myopia severity, with smartphone-based pupillometry offering a potential non-invasive assessment tool, though causality requires longitudinal validation.

Introduction: The impact of nutritional status on cardiac autonomic function in adolescents from high socioeconomic status (SES) backgrounds, as defined by the Brazilian Economic Classification Criteria, remains unclear, particularly regarding heart rate variability (HRV) parameters. This study aimed to examine associations between nutritional categories (normal weight/overweight/obese) and HRV indices in adolescents from high-SES families. Methods: This cross-sectional study included 201 adolescents aged 11–14 years. HRV was assessed via RMSSD, pNN50, LF, HF, and LF/HF ratio. Data were analyzed using ANOVA and chi-square tests. Results: No significant HRV differences existed across nutritional status: RMSSD (normal: 193.49 ± 246.92ms vs. obese: 168.55 ± 162.43ms; p=0.605), pNN50 (33.39 ± 21.81% vs. 27.71 ± 20.67%; p=0.532), LF (55.85 ± 17.03nu vs. 61.74 ± 16.32nu; p=0.506), HF (155.27 ± 727.00nu vs. 38.10 ± 16.20nu; p=0.629), and LF/HF ratio (1.80 ± 1.57 vs. 2.03 ± 1.29; p=0.951). The values have been expressed as mean ± standard deviation. Chi-square tests confirmed no excess weight-HRV associations (all p&gt;0.30). Discussion: The findings suggested that, among adolescents from high socioeconomic backgrounds, excess weight may not significantly impact cardiac autonomic modulation as measured by HRV. This challenges commonly held assumptions about early autonomic impairment in overweight youth and highlights the potential moderating role of lifestyle and environmental factors. Broader implications point to the need for context-specific cardiovascular risk assessments in pediatric populations. Conclusion: Nutritional status showed no association with HRV parameters in high-SES adolescents. Given the cross-sectional design and the relatively low number of obese participants, the findings of this study should be interpreted with caution. Nevertheless, they suggest preserved autonomic function regardless of nutritional status and emphasize potential protective lifestyle factors in this population.

Diabetes-Associated Autonomic-Related Structural Alterations (DAAS) is a severe complication of type 1 diabetes mellitus (T1DM) characterized by autonomic nerve fiber dysfunction in the heart and blood vessels. This study aimed to elucidate the histopathological mechanisms underlying DAAS and evaluate the therapeutic potential of MCC950, an NLRP3 inflammasome inhibitor, in a Wistar rat model. Male Wistar rats were divided into control and T1DM groups, with diabetes induced by streptozotocin (STZ) injection. Following confirmation of DAAS through elevated serum noradrenaline levels, diabetic rats were subdivided into positive control (insulin-treated), treatment (MCC950), and untreated groups. The stellate ganglia, thoracic aorta, and left ventricle were dissected for histological examination using Haematoxylin and Eosin (H&E) and Masson Trichrome staining. STZ-induced hyperglycemia was evident by Week 1 and sustained throughout the study. Serum noradrenaline levels significantly increased by Week 14 in diabetic rats, indicating DAAS onset. Histological analysis revealed atrophy in stellate ganglia, endothelial damage in the thoracic aorta, and myocardial fibrosis in untreated diabetic rats. MCC950 treatment preserved ganglionic structure, mitigated vascular damage, and reduced myocardial fibrosis, demonstrating its potential in attenuating DAAS progression. These findings highlight MCC950 as a promising therapeutic agent for DAAS by targeting inflammation and preserving autonomic and cardiovascular function. Further investigations are warranted to validate MCC950's efficacy in human trials, with the potential to improve clinical outcomes for T1DM patients at risk of DAAS.

Cardiac arrhythmias remain a major cause of morbidity and mortality, and current therapies have notable limitations. Vagus nerve stimulation (VNS), which modulates autonomic tone, has emerged as a potential adjunctive treatment. This systematic review evaluated the efficacy of invasive and noninvasive VNS in patients with atrial fibrillation, heart failure, myocardial infarction, and other rhythm disorders. A search of PubMed, Scopus, and Web of Science identified 21 randomized controlled trials, including 11,368 patients. Overall, VNS was associated with reduced atrial fibrillation incidence and burden, improved autonomic function and left ventricular ejection fraction in heart failure, and reduced arrhythmic events and infarct biomarkers after myocardial infarction. Additional benefits were observed in conditions such as vagally mediated atrioventricular block and postural orthostatic tachycardia syndrome. Across studies, VNS demonstrated a favorable safety profile. These findings suggest that VNS may be a promising multimodal strategy for reducing arrhythmia burden and improving cardiac autonomic regulation, although larger confirmatory trials are needed.

Assessing aging-related changes of the brain-heart interconnection using functional near-infrared spectroscopy.