Physiological Reports最新文献

Shift workers have a 40% higher risk for cardiovascular disease (CVD) compared to people who work day shifts. However, the acute impact of shift work on CVD risk factors in free-living settings remains unclear. We therefore investigated the impact of acute night shift work on factors related to cardiovascular health including blood pressure (BP) and sleep duration. Twenty-four rotating shift workers (19F, 23 ± 4 y, BMI: 23 ± 3 kg/m²; mean ± SD) participated in a quasi-randomized crossover study. Assessments were conducted over the course of 1 day shift and one night shift in a free-living setting. BP was measured every 30 min by an ambulatory monitor. Sleep and wake times were recorded. Mixed effects models were conducted to examine changes in variables between conditions. Acute night shift work was associated with significantly higher 24 h systolic (107 ± 1 vs. 104 ± 1 mmHg; p < 0.0001) and diastolic (67 ± 1 vs. 64 ± 1 mmHg; p < 0.0001) BP, as well as blunted dipping patterns in systolic BP (8 ± 1 vs. 12 ± 1%; p = 0.032), as compared to day shift work. Sleep duration was significantly shorter during the night shift as compared to the day shift (4 h 04 ± 19 min vs. 8 h 22 ± 18 min; p < 0.0001). As little as one night of shift work in a free-living setting is sufficient to induce multiple CVD risk factors including increased BP and reduced sleep duration in healthy adults. It is critical to identify strategies to prevent or attenuate the negative impact of shift work on CVD risk in a large portion of the working population.

Clinically accepted for treatment of chronic pain 10 kHz-frequency electric spinal cord stimulation (10 kHz-SCS) releases more power in tissue compared to conventional low-frequency (<100 Hz) stimulation due to increased duty cycle. This is equivalent to the release of more heat in a surrounding tissue, which may change the functional state of affected neural elements. In the case of SCS, plausible candidates to be affected by thermal a component of kHz-frequency electric field stimulation (kHz-FS) are dorsal column axons and neurons of the superficial layers of the dorsal horn. In this study, we tested the hypothesis that joule heat produced by kHz-FS modulates neuronal excitability. In slices of the mouse spinal cord, we monitored membrane potential and membrane input resistance in neurons of lamina II during exposure to kHz-FS. Surprisingly, we found no correlation between temperature rise and changes of membrane parameters. Furthermore, the depolarizing effect of kHz-FS was always immediate and remained persistent throughout stimulation, whereas rise of temperature was delayed for 1-2 s and reached its saturation level within the following few seconds. Thus, we concluded that the thermal component has an insignificant role in the mechanism of kHz-FS action.

Physical activity is commonly used for both measuring and treating dysfunction. While preclinical work has been historically biased towards males, the inclusion of both males and females is gaining popularity. With the increasing inclusion of both sexes, it is imperative to determine sex differences in common behavioral assays. This was a secondary analysis of healthy naïve mice to determine baseline sex differences in three activity assays: voluntary wheel running (32 mice), forced treadmill running (178 mice), and open field (88 mice). In voluntary wheel running, females showed greater distance run, running time, bout duration, and speed, but no difference in total bouts. In forced treadmill running, females showed greater time to exhaustion, but no difference in maximum speed attained. In open field, males showed greater active time but no difference in distance and speed over 30 min; however, male mice showed a downward trajectory in distance and speed over the final 20 min of testing, whereas females did not. These data suggest that male mice demonstrate comparable activity intensity to female mice but do not match females' duration of activity, especially for volitional tasks. Researchers utilizing these assays should account for sex differences as they could mask true findings in an experiment.

The effects of angiotensin II (AngII) on blood vessel development and remodeling have been extensively investigated in mice and humans. However, its action on the vessels in the zebrafish remains largely unknown. To investigate whether AngII affects vascular morphology in vivo, we administered AngII into the endothelial-specific transgenic reporter zebrafish (Tg[kdrl:EGFP]) at the 1-cell stage. The average dorsal aortic diameter of five serial positions was significantly increased by 20% in AngII-injected zebrafish compared with buffer-injected controls at 5 days post-fertilization. Histological studies in AngII-injected zebrafish at 8 weeks post-fertilization showed that elastic fiber formation was partly attenuated, with enhanced matrix metalloproteinase-2 expression in the dorsal aorta without dilation. These results suggest that AngII induced transient aortic expansion in early larvae and may affect vascular elastic fiber formation in adult zebrafish. The use of the AngII-injected zebrafish model is a potential tool to dissect the mechanisms of disruption of elastic vascular wall formation in the aorta.

Tubulointerstitial fibrosis is a characteristic hallmark of chronic kidney disease (CKD). Metabolic perturbations in cellular energy metabolism contribute to the pathogenesis of CKD, but the chemical contributors remain unclear. The aim of this investigation was to use two dimensional ¹H-nuclear magnetic resonance (2D-COSY) metabolomics to identify the chemical changes of kidney fibrogenesis. An in vitro transforming growth factor-β1 (TGF-β1)-induced model of kidney fibrogenesis with human kidney-2 (HK-2) proximal tubular epithelial cells (PTEC) was used. The model was validated by assaying for various pro-fibrotic molecules, using quantitative PCR and Western blotting. 2D-COSY was performed on treated cells. Morphological and functional changes characteristic of tubulointerstitial fibrosis were confirmed in the model; expression of fibronectin, collagen type IV, smooth muscle actin, oxidative stress enzymes increased (p < 0.05). NMR metabolomics provided evidence of altered metabolite signatures associated with glycolysis and glutamine metabolism, with decreased myo-inositol and choline, and metabolites of the oxidative phase of the pentose phosphate pathway with increased glucose and glucuronic acid. The altered PTEC cellular metabolism likely supports the rapid fibrogenic energy demands. These results, using 2D-COSY metabolomics, support development of a biomarker panel of fibrosis detectable using clinical magnetic resonance spectroscopy to diagnose and manage CKD.

Lengthy periods of inactivity are experienced by substitutes during a soccer match, which can decrease muscle temperature, ultimately impacting performance. This study aimed to determine the effects of using a passive heat intervention in both a cold (2°C) and thermoneutral (18°C) environment on simulated soccer performance and perceptual responses. On four occasions, 14 trained male players, completed a pre-match warm-up, followed by 45 min of rest. After, players completed a half-time re-warm-up, followed by an additional 15 min of rest, simulating 60 min as a substitute. During these periods, players wore tracksuit bottoms (CON), or heated trousers (HEAT), over soccer attire. Once 60 min concluded, participants performed a Soccer Match Simulation (SMS) to assess physical performance. HEAT improved 15 m sprint performance in 2°C (2.8%; p < 0.001) and 18°C (2.6%; p < 0.001) conditions. Further, in HEAT, a significant trial and time effect on countermovement jump height and repeated sprint performance was observed in both 2 and 18°C. Upon match entry, participants felt warmer (p < 0.01), more comfortable (p < 0.01), and felt an increase in match readiness following HEAT, during both conditions. Applying heated garments before match entry for soccer substitutes positively impacts physical performance and match readiness in thermoneutral and cold environments.

Advancing age and estrogen deficiency increases susceptibility of post-menopausal women (PMW) to abdominal obesity and manifestation of cardiometabolic disease. There is limited evidence on the effect of lifestyle interventions on adiposity markers within at-risk PMW. Therefore, this study aims to evaluates an 8-weeks of home-based, equipment-free, interval training (HEFIT) with or without Mediterranean-style diet (MD) on adiposity markers in physically inactive, postmenopausal women with overweight/obesity. Thirty PMW (56.7 ± 3.9 years, BMI: 30.5 ± 5.2 kg/m²) were randomly assigned to three groups: (i) Ex; HEFIT thrice weekly/week, (ii) EX + MD, or (iii) CTL; control. Visceral Adiposity Index (VAI), body weight, BMI, waist and hip circumference (WC; HC), visceral adipose tissue (VAT), total body fat percentage, leptin, and adiponectin were determined pre- and post-8-week intervention. There was no significant between group effect on VAI. Compared to CTL, a significant between group reduction was seen in weight, BMI, and WC in both EX and EX+D (p < 0.05). Leptin and adiponectin remained unchanged in all groups (p > 0.05). Adherence rates were 85% and 96% for EX and EX+MD, respectively, and 80% of EX+D of participants had optimal adherence to diet. Concluding HEFIT with or without dietary changes could improve adiposity in overweight/obese postmenopausal women.

Elevated glucocorticoid levels with reduced glucocorticoid responsiveness have been reported in chronic inflammatory conditions. Activation of neurons in the nucleus of the solitary tract by transcutaneous auricular vagus nerve stimulation (taVNS) may activate inhibitory pathways projecting to the hypothalamic paraventricular nucleus (PVN), thus inhibiting corticotropin-releasing hormone (CRH) release and improving glucocorticoid dysfunction in chronic inflammatory conditions. Healthy adults (n = 12) participated in experimental (taVNS) and control (sham-taVNS) sessions at least 4 days apart. A 30-min baseline recording was followed by 30 min of taVNS or sham-taVNS and 40 min of recovery. Ten minutes into taVNS or sham-taVNS, a mental arithmetic stress test (MAST) was conducted for 15 min. The MAST increased heart rate, low frequency (LF) heart rate variability (HRV), and the LF to high frequency ratio of HRV, confirming sympathetic activation. Salivary cortisol levels during the MAST were lower during taVNS (49.5 ± 48.0% from baseline; mean ± SD) compared to sham-taVNS (106.0 ± 81.1% from baseline; mean ± SD; p < 0.05). In a psoriasis patient, daily taVNS for 3 months reduced diurnal salivary cortisol levels from 58.2 ± 35.2 (ng/mL)*h (mean ± SD) to 34.9 ± 13.8 (ng/mL)*h (mean ± SD). While it is possible that taVNS inhibited CRH-releasing neurons in the PVN, our study design did not allow to confirm this potential mechanism.

Emerging evidence suggests that the vagus nerve can modulate the immune system in experimental settings. Vagus nerve stimulation (VNS), initially developed for managing epilepsy, is now being explored as a treatment for autoimmune diseases due to its potential immunomodulatory effects. This systematic review evaluates the therapeutic potential of VNS in autoimmune diseases by critically appraising findings from human clinical studies. This systematic review was conducted in accordance with the PRISMA guideline, with a comprehensive literature search performed in Ovid, Cochrane, and PubMed databases up to July 2024. Studies focusing on VNS in patients with autoimmune diseases were eligible, and the quality of study was assessed using the QualSyst tool. Of the 53 papers identified for full-text assessment, 19 studies met the eligibility criteria. Findings suggest that VNS is a promising adjunctive therapy for Crohn's disease and rheumatoid arthritis, showing potential to alleviate symptoms and modulate immune responses. The efficacy and safety of VNS vary widely across studies, highlighting the complex nature of autoimmune diseases and the diverse mechanisms of VNS action. Future research should prioritize large-scale, randomized controlled trials with standardized protocols to further elucidate the efficacy, long-term safety, and optimal parameters of VNS across various autoimmune conditions.

Aim was to evaluate alterations of the non-linear short-term scaling exponent alpha1 of detrended fluctuation analysis (DFAa1) of heart rate (HR) variability (HRV) as a sensitive marker for assessing global physiological demands during multiple running intervals. As a secondary analysis, agreement of ECG-derived respiratory frequency (EDR) compared to respiratory frequency (RF) derived from the metabolic cart was evaluated with the same chest belt device. Fifteen trained female and male long-distance runners completed four running bouts over 5 min on a treadmill at marathon pace. During the last 3 min of each bout gas exchange data and a single-channel ECG for the determination of HR, DFAa1 of HRV, EDR and RF were analyzed. Additionally, blood lactate concentration (BLC) was determined and rating of perceived exertion (RPE) was requested. DFAa1, oxygen consumption, BLC, and RPE showed stable behaviors comparing the running intervals. Only HR (p < 0.001, d = 0.17) and RF (p = 0.012, d = 0.20) indicated slight increases with small effect sizes. In addition, results point towards inter-individual differences in all internal load metrics. The comparison of EDR with RF during running revealed high correlations (r = 0.80, p < 0.001, ICC_3,1 = 0.87) and low mean differences (1.8 ± 4.4 breaths/min), but rather large limits of agreement with 10.4 to -6.8 breaths/min. Results show the necessity of EDR methodology improvement before being used in a wide range of individuals and sports applications. Relationship of DFAa1 to other internal load metrics, including RF, in quasi-steady-state conditions bears the potential for further evaluation of exercise prescription and may enlighten decoupling mechanisms during prolonged exercise bouts.