Level Of Sympathetic Activity Research Articles

Relationship between central hemodynamic parameters and body composition and the functional state of neuro-autonomic regulation in young men

The aim of the study is to examine the relationship between central hemodynamic parameters and body composition by considering baseline functional state of neuro-autonomic regulation according to the index of regulatory system activity (IRSA) in young men. Material and methods. A total of 44 male participants were divided into three groups based on the IRSA level. The first group included 26 men with an optimal IRSA level. The second and third groups, each of 9 men, with moderate and high IRSA levels, respectively. The functional state of cardiovascular system was assessed using a device “REOKOM” (Kharkiv). The measurement of body composition was performed by weight-scale “TANITA BC-601” (Japan). The functional state of autonomic nervous system was assessed using a device “CARDIOLAB” (Kharkiv). Results. Our results have demonstrated higher hemodynamic parameters in men with moderate and high level of IRSA. Men with elevated level of sympathetic activity had the highest indices of the pumping function of the heart, and those with the balance between parasympathetic and sympathetic branches had the lowest indices of the pumping heart function. As for the indicators of total peripheral resistance and specific peripheral resistance, another trend was seen, namely, individuals with a balanced state of autonomic nervous regulation had the highest parameters, and those with a predominance of sympathetic tone had the lowest ones. Close correlations have been found between increased levels of regulatory mechanism tension and cardiohemodynamic parameters. An indicator analysis of the body component composition has revealed a significant increase in body mass index, total and visceral fat content in the examined groups with moderate and severe regulatory system tension. In addition, correlations have been found between IRSA and constituting components of body composition. Conclusions. The group assignment of the examined individuals according to IRSA has shown that a high tension of the regulatory mechanisms increased the load on the cardiovascular system, as indicated by higher indicators of central hemodynamics. In individuals with an optimal level of regulatory system functioning, the cardiovascular system activity is optimal and less energy consuming.

The Clinical Significance and Application of Heart Rate Variability in Dialysis Patients: A Narrative Review.

Autonomic nervous system (ANS) dysfunction is prevalent in end-stage kidney disease (ESKD) patients, carrying significant risks for morbidity and mortality. Heart rate variability (HRV) is a simple and non-invasive method to evaluate ANS functions and predict prognoses in specific patient populations. Since there is a lack of a clear understanding of the clinical significance of HRV in predicting prognoses in ESKD patients, an updated review on this topic is urgently warranted. The clinical significance of HRV in dialysis patients includes its associations with metabolic syndrome, nutritional status, intradialytic hypotension, vascular access failure, major adverse cardiovascular events, and mortality. These findings underscore the essential role of the autonomic reserve, which might denote the elevation of ANS activity as a response to external stimulus. Patients with a higher level of sympathetic activity at the resting stage, but who are unable to adequately elevate their sympathetic activity under stress might be susceptible to a worse outcome in critical circumstances. Further applications of HRV include HRV biofeedback, risk classification, and real-time HRV monitoring. Overall, HRV is an optimal tool for predicting prognoses in dialysis patients. Further study is encouraged in order to gain a clearer understanding of the clinical significance and application of HRV, and thereby enhance the care of ESKD patients.

IMPAIRED BETA-ADRENERGIC VASODILATOR FUNCTION IN HYPERTENSIVE PATIENTS WITH SYMPTOMS OF DEPRESSION

Objective: Hypertension and depression are amongst the most common chronic physical and mental conditions worldwide. The two conditions cluster, however the mechanisms underlying the association are not well understood. Hypertension complicated by affective disorders may be characterised by high sympathetic activity. We investigated whether symptoms of depression may be associated with impaired endothelium-dependent beta2-adrenergic vasodilator responses. Design and method: Hypertensive subjects with no previous history of diabetes or cardiovascular disease were recruited from the hypertension outpatient service at St. Thomas’ Hospital, London. Detailed medical history and baseline characteristics including blood pressure (BP), heart rate (HR), routine biochemistry including C-reactive protein (CRP) and low-density lipoprotein (LDL) were obtained during a single study visit. Plasma concentrations of normetadrenaline were measured as a marker of resting sympathetic activity. Depression symptom severity was assessed using the Patient Health Questionnaire-9 (PHQ-9). The pulse wave response to the beta2-adrenergic vasodilator salbutamol (PWRS) was assessed using radial tonometry to measure the change in augmentation index after inhalation of 200μg salbutamol from a metered dose inhaler with spacer device. Results: 100 subjects (62% male, mean ± SD age 41.0±11.6 years) were recruited. 79% were on pharmacological treatment for hypertension. Mean PHQ-9 depression score was 8.8±6.2, consistent with a high prevalence of depression. After adjusting for confounders (age, sex, smoking status, body mass index, BP, HR, CRP, LDL, treatment for hypertension), PWRS was significantly related to depression score (Beta= 0.447, P=0.002). Depression score was also significantly associated with plasma concentrations of normetadrenaline (Beta= 0.605, P<0.001) and after adjusting for plasma normetadrenaline level, the association between PWRS and depression score was no longer significant (Beta= 0.343, P=0.102). Conclusions: These results suggest that in hypertensive subjects with depression, an impaired endothelium-dependent beta2-adrenergic vasodilator response is mediated by a high level of sympathetic activity which could contribute to cardiovascular complications.

Heart rate variability and perception of mental stress among medical students and residents at an emergency department

BackgroundWhen Medical Residents (MR) and Medical Students (MS) are assigned to the demanding environment of an Emergency they inevitably encounter stress. The aims of this study are to measure short-term heart rate variability (HRV) before and after shifts, estimate perceived stress levels, and assess the recovery patterns after their shifts. MethodsWe assessed HRV parameters in MS and MR using the wristband physiological monitor Polar® Verify Sense before and after day (DS) and night shifts (NS). Perceived stress levels were evaluated using the simplified State Trait Anxiety Inventory (STAI-S6) and the Subjective Units of Distress Scale. ResultsThis study included 60 participants of which 55% were female with a mean age of 26 years. MS presented significant reduction in sympathetic nervous system index after DS [0.68 (0.01–2.42) vs −0.22 (−0.75–1.13), p < 0.01] and NS [0.87 (−0.28–1.45) vs 0.06 (−0.70–1.04), p < 0.01], while MR maintained the same levels of sympathetic activity [DS: 1.17 (0.04 –2.88) vs 0.93 (0.50–1.41), p = 0.14; NS: 1.37 (0.76–2.21) vs 1.29 (0.35–2.18), p = 0.40]. Psychological data from STAI-S6 showed statistically significant differences when comparing before and after DS in both groups, with more perceived stress after than before DS (MS: 12 ± 4 vs 14 ± 4, p = 0.04; MR: 14 ± 4 vs 16 ± 4, p = 0.04), which was not observed at NS (MS: 12 ± 3 vs 12 ± 3, p = 0.84; MR: 15 ± 3 vs 15 ± 4, p = 0.40). ConclusionsShort-term HRV recordings before and after day or night shifts among MR and MS revealed heightened sympathetic activity preceding each shift, with a more sustained increase observed in the MR population and more perceived stress after day shifts in both groups.

Maternal high-fat diet changes breathing pattern and causes excessive sympathetic discharge in juvenile offspring rat.

Early life over-nutrition, as experienced in maternal obesity, is a risk factor for developing cardiorespiratory and metabolic diseases. Here we investigated the effects of high-fat diet (HFD) consumption on the breathing pattern and sympathetic discharge to blood vessels in juvenile offspring from dams fed with HFD (O-HFD). Adult female Holtzman rats were given a standard diet (SD) or HFD from 6 wk before gestation to weaning. At weaning (P21), the male offspring from SD dams (O-SD) and O-HFD received SD until the experimental day (P28-P45). Nerve recordings performed in decerebrated in situ preparations demonstrated that O-HFD animals presented abdominal expiratory hyperactivity under resting conditions and higher vasoconstrictor sympathetic activity levels. The latter was associated with blunted respiratory-related oscillations in sympathetic activity, especially in control animals. When exposed to elevated hypercapnia or hypoxia levels, the O-HFD animals mounted similar ventilatory and respiratory motor responses as the control animals. Hypercapnia and hypoxia exposure also increased sympathetic activity in both groups but did not reinstate the respiratory-sympathetic coupling in the O-HFD rats. In freely behaving conditions, O-HFD animals exhibited higher resting pulmonary ventilation and larger variability of arterial pressure levels than the O-SD animals due to augmented sympathetic modulation of blood vessel diameter. Maternal obesity modified the functioning of cardiorespiratory systems in offspring at a young age, inducing active expiration and sympathetic overactivity under resting conditions. These observations represent new evidence about pregnancy-related complications that lead to the development of respiratory distress and hypertension in children of obese mothers.NEW & NOTEWORTHY Maternal obesity is a risk factor for developing cardiorespiratory and metabolic diseases. This study highlights the changes on the breathing pattern and sympathetic discharge to blood vessels in juvenile offspring from dams fed with HFD. Maternal obesity modified the functioning of cardiorespiratory systems in offspring, inducing active expiration and sympathetic overactivity. These observations represent new evidence about pregnancy-related complications that lead to the development of respiratory distress and hypertension in children of obese mothers.

Electrodermal Activity Monitoring for Stroke Patients Stress States, Еmotional Disturbances, Rehabilitation Measures Effectiveness Specification: a Pilot Study

INTRODUCTION. The level of stress experienced by stroke patients (caused by anxiety-depressive disorders, pain and motor deficiency) is still difficult to assess adequately clinically and with the help of existing diagnostic questionnaires, whereas their presence in a state of pronounced discomfort significantly affects the overall functioning and effectiveness of rehabilitation measures. In connection with the above, of interest are the methods aimed at objectification of stress level, such as determination of sympathetic activation byregistration of cutaneous conductivity, which, according to the literature, can be a reliable marker of affective pathology and chronic pain. AIM. To assess the possibility of using the NeonFSC stress monitoring system, RU No. RZN 2021/16179 dated December 29, 2021 for diagnostics by recording the skin conduction of stress, pain sensations and emotional pathology in stroke patients, and determining the effectiveness of the treatment and rehabilitation measures taken to correct the above disorders. MATERIAL AND METHODS. Thirty-five stroke patients were examined clinically and anamnesthetically, clinico-neurologically, clinicopsychopathologically,using diagnostic scales and recording electrodermal activity. RESULT AND DISCUSSION. The NeonFSC system determines the level of sympathetic activation in stroke patients, correlated with clinical parameters (neurological deficit, severity of pain, anxiety and depression) and helps to assess the dynamics of discomfort experienced by the patient as a result of rehabilitation measures. The use of electrodermal activity monitoring in a comprehensive examination of patients increased the diagnosis of emotional pathology and pain by 30%, objectified the presence of distress or its absence. CONCLUSION. The NeonFSC system is promising for use in comprehensive diagnosis and assessment of the dynamics of anxietydepressive disorders, pain, and other distress-inducing conditions, as well as to determine the adequacy of physical activities used in rehabilitation for various diseases.

Reduced postoperative pain in patients receiving nociception monitor guided analgesia during elective major abdominal surgery: a randomized, controlled trial

The Nociception Level index (NOL™) is a multiparameter index, based on artificial intelligence for the monitoring of nociception during anesthesia. We studied the influence of NOL-guided analgesia on postoperative pain scores in patients undergoing major abdominal surgery during sevoflurane/fentanyl anesthesia. This study was designed as a single-center, prospective randomized, controlled study. After Institutional Review Board approval and written informed consent, 75 ASA 1–3 adult patients undergoing major abdominal surgery, were randomized to NOL-guided fentanyl dosing (NOL) or standard care (SOC) and completed the study. The sevoflurane target MAC range was 0.8–1.2. In the NOL-guided group (N = 36), when NOL values were > 25 for at least 1 min, a weight adjusted fentanyl bolus was administered. In the control group (N = 39) fentanyl administration was based on hemodynamic indices and clinician judgement. After surgery, pain, was evaluated using the Numerical Rating Scale (NRS) pain scale, ranging from 0 to 10, at 15 min intervals for 180 min or until patient discharge from the PACU. Median postoperative pain scores reported were 3.0 [interquartile range 0.0–5.0] and 5.0 [3.0–6.0] at 90 min in NOL-guided and control groups respectively (Bootstrap corrected actual difference 1.5, 95% confidence interval 0.4–2.6). There was no difference in postoperative morphine consumption or intraoperative fentanyl consumption. Postoperative pain scores were significantly improved in nociception level index-guided patients. We attribute this to more objective fentanyl dosing when timed to actual nociceptive stimuli during anesthesia, contributing to lower levels of sympathetic activation and surgical stress. Clinicaltrials.gov identifier: NCT03970291 date of registration May 31, 2019.

GLP1R Attenuates Sympathetic Response to High Glucose via Carotid Body Inhibition.

Aberrant sympathetic nerve activity exacerbates cardiovascular risk in hypertension and diabetes, which are common comorbidities, yet clinically sympathetic nerve activity remains poorly controlled. The hypertensive diabetic state is associated with increased reflex sensitivity and tonic drive from the peripheral chemoreceptors, the cause of which is unknown. We have previously shown hypertension to be critically dependent on the carotid body (CB) input in spontaneously hypertensive rat, a model that also exhibits a number of diabetic traits. CB overstimulation by insulin and leptin has been similarly implicated in the development of increased sympathetic nerve activity in metabolic syndrome and obesity. Thus, we hypothesized that in hypertensive diabetic state (spontaneously hypertensive rat), the CB is sensitized by altered metabolic signaling causing excessive sympathetic activity levels and dysfunctional reflex regulation. Using a hypothesis-free RNA-seq approach, we investigated potential molecular targets implicated in energy metabolism mediating CB sensitization and its regulation of sympathetic outflow in experimental hypertension. Identified targets were characterized using molecular and functional techniques assessing peripheral chemoreflex sensitivity in situ and in vivo. We discovered GLP1R (glucagon-like peptide-1 receptor) expression in the CBs of rat and human and showed that its decreased expression is linked to sympathetic hyperactivity in rats with cardiometabolic disease. We demonstrate GLP1R to be localized to CB chemosensory cells, while targeted administration of GLP1R agonist to the CB lowered its basal discharge and attenuated chemoreflex-evoked blood pressure and sympathetic responses. Importantly, hyperglycemia-induced peripheral chemoreflex sensitization and associated basal sympathetic overactivity were abolished by GLP1R activation in the CB suggesting a role in a homeostatic response to high blood glucose. We show that GLP1 (glucagon-like peptide-1) modulates the peripheral chemoreflex acting on the CB, supporting this organ as a multimodal receptor. Our findings pinpoint CBs as potential targets for ameliorating excessive sympathetic activity using GLP1R agonists in the hypertensive-diabetic condition.

Effects of Resistance Training on Skin Temperature and Its Relationship with Central Nervous System (CNS) Activation.

The aim of this work was to relate the activation of the sympathetic and parasympathetic nervous systems with the skin temperature (Tsk) of the lower limbs after a resistance training exercise. Under controlled conditions, the average Tsk in the areas of the anterior and posterior thighs, knees and legs was obtained with a thermal imager and the parasympathetic and sympathetic activation was registered with an Omegawave® device on 20 healthy and trained male volunteers (25.39 ± 8.21 years) before exercise, immediately after standard resistance training (3 exercises (2 quadriceps + 1 hamstrings) × 4 sets × 10 repetitions (70% 1RM), 90-sec recovery) and after 20 min of recovery. The results showed a significant effect of exercise and recovery on Tsk in all regions of interest (ROIs) considered (p < 0.05) and strong inverse relationships between sympathetic and parasympathetic activation values. Significant results were found for the total variation of Tsk (p < 0.05) with highly positive values for subjects with lower sympathetic activation and almost null or even negative values for those with higher sympathetic activation. Sympathetic activity was a significant predictor of total Tsk variation in the anterior thigh, posterior thigh and anterior knee but not in the posterior knee, anterior leg, and posterior leg. Baseline Tsk was a significant predictor of total Tsk variation the all ROIs except in the posterior knee. Tsk measured by thermography could be used to estimate the level of participation of muscle areas in exercise and registering the level of sympathetic activation before exercise could be interesting in predicting the athlete’s physiological response to strength training.

Abstract 9397: Sonothrombolysis Improves Cardiac Segmental Contractility, Myocardial Perfusion and Baroreflex Gain in Patients With ST-segment Elevation Myocardial Infarction (stemi) in Long-Term Follow-Up

Sonothrombolysis (Sono) has improved microvascular obstruction, global contractility and infarct area after STEMI. Objective: To evaluate the long-term effect of Sono and its physiologic mechanisms in a subgroup of 51 STEMI patients (percutaneous coronary intervention-PCI (N=24) and PCI+Sono (N=27)) from previous randomized study. All patient were treated with PCI and those also treated with Sono received frequent image-guided diagnostic high mechanic index impulses applied to the myocardial contrast-enhanced areas (microbubbles) in the apical views (1.8 MHz; 1.1 to 1.3 MI; &lt;5-μ pulse duration). Evaluations were at pre-treatment, 1 month (ultrasound-US with contrast agent) and at averaged 34±17 months after STEMI (US with contrast agent; cardiac and peripheral sympathetic activity by means of 123 I-MIBG cardiac scintigraphy and microneurography; baroreflex gain of heart rate (HR) control by means of transfer function analysis). (For significance: P level ≤ 0.05). US values are on table. Adding, PCI+Sono showed lower left ventricular end-diastolic volume (LVEDV) remodelling (22±36 vs. 44±42%, P&lt;0.05). Cardiac scintigraphy showed similar late Heart/Mediastinum ratio and similar washout rate between groups. Muscle sympathetic nervous activity was also similar in both groups. PCI+Sono showed higher baroreflex gain of HR control (8±3 vs. 6±2 ms/mmHg, P=0.05), indicating an improved baroreflex sensitivity. In addition, perfusion score index correlated positively with wall motion score index (r=0.97, P&lt;0.001) and washout rate (r=0.30, P=0.04). LV ejection fraction correlated negatively with wall motion score index (r=-0.53), perfusion score index (r=-0.48) and LVEDV (r=-0.29) (P&lt;0.05). In conclusion, Sono added to PCI improved contractility and myocardial perfusion in STEMI. Despite high level of sympathetic activity, baroreflex gain of HR was ameliorated in PCI+Sono patients, probably due to better myocardial perfusion and lower LV remodelling.

Maybe angiotensin II is getting on our nerves, and the role of exercise.

Maybe angiotensin II is getting on our nerves, and the role of exercise.

The Effect of Surgical Mask Use in Anaerobic Running Performance

COVID-19 restrictions stipulate the mandatory use of surgical masks during outdoor and indoor physical activities. The impact of this on athletic performance and especially on anaerobic physical activities is poorly known. The aim of the present research was to analyze the effect of surgical mask use on the anaerobic running performance of athletes. Modifications in running time, blood lactate, blood glucose, blood oxygen saturation, subjective perceived stress, rating of perceived exertion, and heart rate variability were measured in 50 m and 400 m maximal running tests with and without the use of surgical masks in 72 athletes. The use of a surgical mask increased blood lactate concentration, sympathetic autonomic modulation, perceived exertion, perceived stress, and decreased blood oxygen saturation in 50 and 400 m running tests. Thus, the higher levels of blood lactate and lower blood oxygen saturation require adaptation of the athlete’s rest and recovery periods to the acute workload. The higher level of sympathetic activation makes the acute and chronic control of autonomic modulation essential for an efficient training periodization. Finally, the use of acid buffers such as bicarbonate or sodium citrate would be a recommended ergogenic strategy.

The role of thyrostatic agents in the treatment of chronic heart failure patients with comorbid coronary artery disease and thyrotoxicosis

Background: Thyroid dysfunction exerts a pronounced effect on the cardiovascular system, and, if comorbid with an existing cardiovascular disorder, may lead to a significant deterioration in the outcome, thus obviating the need for timely diagnosis and therapy optimization.Aim: To evaluate the effect of combination therapy, including thyrostatics, on the clinical symptoms of chronic heart failure (CHF), heart rate variability, NT-proBNP concentration, and structural and functional parameters of the left heart in patients with comorbid coronary artery disease (CAD) and thyrotoxicosis.Materials and methods: This open-label comparative study included 77 patients aged 45–65 years. The study group consisted of 36 patients with thyrotoxicosis, CAD and CHF II–III functional class, whereas the comparison group consisted of 41 patients with thyrotoxicosis without cardiovascular diseases. The patients were assessed clinically at baseline and after 6 months of therapy with addition of a thyrostatic, with tolerance to physical activity, measurements of NT-proBNP levels, 24-hour Holter monitoring, and echocardiography.Results: At 6 months of the combination therapy including a thyrostatic, with stable drug-induced euthyroidism, the patients in the group 1 showed an increase in the distance of a 6-minute walking test (p&lt;0.001) and a decrease in CHF clinical symptoms. The incidence of heart rhythm disorders decreased (supraventricular extra systoles from 31% to 16%, ventricular extra systoles from 21% to 4%, atrial fibrillation from 32% to 23%; p&lt;0.05), with a positive trend for spectral and temporal parameters of heart rate variability. The NT-proBNP level in patients with CAD, CHF and thyrotoxicosis decreased by 42.9% (p=0.001). During euthyrosis, echocardiography in the patients with ischemic CHF and concomitant thyrotoxicosis showed a significant increase in stroke volume (p=0.03), stroke ejection index (p=0.04), left ventricular ejection fraction (p=0.01), a decrease in the value of myocardial stress (p=0.02), and transmitral blood flow parameters (E/A, p&lt;0.05). This indicates an improvement in systolic and diastolic left ventricular function after normalization of thyroid function.Conclusion: The inclusion of thyreostatics to the combination therapy and the achievement of euthyrosis have contributed to increased tolerance to physical activity, reduction of sympathetic activity level of the autonomic nervous system and frequency of heart rhythm disorders, reduced the NT-proBNP levels, improved systolic and diastolic left ventricular function in patients with ischemic CHF and concomitant thyrotoxicosis.

Psychophysiological effects of human-dog interaction in university students exposed to a stress-induced situation using the Trier Social Stress Test (TSST).

Abstract Enjoying the company of a good-natured dog can lend support to a person in a stressful situation. This presence brings benefits across different areas of human well-being and leads to a decrease in levels of sympathetic activation and subjective distress which are triggered in social anxiety situations. This study seeks to provide evidence of these benefits relative to physiological variables—heart rate and blood pressure—as well as a subjective variable, namely anxiety. Thirty-six university students (80% female, M=22.4, SD=4,32) exposed to a stress-induced situation using the Trier Social Stress Test (TSST) participated in the study. This type of scenario produces an increase in heart rate, blood pressure, and subjective anxiety levels. The decline in these variable levels was assessed based on whether the participants were alone or accompanied by a friendly dog. Through random selection, half of the students could pet the animal during the stress-induced phase (experimental group), whereas the other half had a toy dog to hold (control group). The levels of all three dependent variables were recorded at three different stages: the pretest relaxation phase, the stress- and anxiety-induced test phase, and the relaxation or return-to-calm posttest phase. The results revealed that the dog’s presence during the test phase considerably reduced the levels of anxiety and heart rate experienced by the experimental group participants compared to the control group. No significant differences in blood pressure were observed between both groups during this phase. The results of this research coincide with earlier studies that report on the beneficial effects of human–animal interaction, while highlighting the importance of analyzing this interaction in the field of psychology.

Autonomic functioning among cocaine-exposed kindergarten-aged children: Examination of child sex and caregiving environmental risk as potential moderators

The purpose of this study was to examine the hypothesis that child sex moderates the association between prenatal cocaine exposure (PCE) and autonomic functioning as well as to examine the role that caregiving environmental risk played in sex differences in autonomic functioning among exposed children. Measures of the parasympathetic nervous system (indexed by respiratory sinus arrhythmia [RSA]) and the sympathetic nervous system (indexed by skin conductance level [SCL]) were obtained from 146 (75 cocaine-exposed, 38 male; and 71 nonexposed, 36 male) children during baseline and a task designed to elicit negative affect (NA). We also examined the role of caregiving environmental risk as a moderator of the association between PCE and autonomic functioning separately for boys and girls. PCE boys had a significantly higher baseline RSA and lower baseline SCL than PCE girls or nonexposed children. Environmental risk also moderated the association between PCE and baseline RSA for boys, but not girls, such that boys with PCE and high environmental risk had the highest baseline RSA. These findings indicate that exposed boys had significantly lower levels of sympathetic activation while at rest. However, for autonomic reactivity, the exposed girls had a larger change in both RSA and SCL relative to nonexposed girls while exposed boys had significantly smaller increases in SCL during environmental challenge. Finally, girls with both PCE and high environmental risk had the highest levels of parasympathetic reactivity during challenge. These results underscore the importance of examining sex differences and considering comorbid environmental risk factors when examining developmental outcomes in cocaine-exposed children and highlight the complexity involved with understanding individual differences in cocaine-exposed populations.

Sympathetic activation in congestive heart failure: an updated overview.

Conclusive evidence demonstrates that the sympathetic nervous system activation is a hallmark of congestive heart failure. This has been shown via a variety of biochemical, neurophysiological, and neuroimaging approaches for studying human sympathetic neural function. The sympathetic activation appears to be an early phenomenon in the clinical course of the disease, closely related to its severity and potentiated by the concomitant presence of other comorbidities, such as obesity, diabetes mellitus, metabolic syndrome, hypertension, and renal failure. The adrenergic overdrive in heart failure is associated with other sympathetic abnormalities, such as the downregulation of beta-adrenergic adrenoreceptors at cardiac level, and exerts unfavorable consequences on the cardiovascular system. These include the endothelial dysfunction, the development of left ventricular hypertrophy, the atherosclerosis development, as well as the generation of atrial and ventricular arrhythmias, and, at very extreme levels of sympathetic activation, the occurrence of microscopic myocardial necrosis. Given the close direct independent relationships detected in heart failure between sympathetic activation and mortality, the adrenergic overdrive has become a target of neuromodulatory therapeutic interventions, which include non-pharmacological, pharmacological, and device-based interventions. For some of these approaches (specifically bilateral renal nerves ablation and carotid baroreceptor stimulation), additional studies are needed to better define their impact on the clinical course of the disease.

Effect of Varying Definitions of Hypopnea on the Calculation of the Apnea-Hypopnea Index May Depend Upon the Level of Sympathetic Activation: Results From a Patient With Posttraumatic Stress Disorder.

CITATIONGupta MA. Effect of varying definitions of hypopnea on the calculation of the apnea-hypopnea index may depend upon the level of sympathetic activation: results from a patient with posttraum...

2025 - RHEUMATOID ARTHRITIS INCREASES SYMPATHETIC NERVOUS SYSTEM DRIVEN HEMATOPOIETIC STEM CELL MOBILISATION AND ATHEROGENESIS

Rheumatoid arthritis (RA) patients have an increased risk for cardiovascular disease (CVD), independent of traditional risk factors such as plasma cholesterol levels. Interestingly, RA patients have elevated activity of the sympathetic nervous system (SNS), which has been known to play an important role in producing and releasing hematopoietic stem and progenitor cells (HSPCs) to produce inflammatory monocytes, the major contributor to atherosclerotic-CVD. Here we investigated whether increased atherosclerotic progression in mice with RA was due to SNS overactivity. We administered 8wk old C57/B6 mice with KBxN serum to elicit RA and found that RA mice had elevated blood HSPCs and myeloid (monocytes/neutrophils) levels. Further investigation of the bone marrow (BM) revealed an expansion of the HSPC pool, with a strong skewing towards myeloid progenitors, explaining the elevation in blood myeloid populations. Sympathetic activity levels, indicated by tyrosine staining, was also increased in the BM of RA mice. Administering RA mice with propanolol (b1/b2 receptor antagonist) and SR59230A (b3 receptor antagonist) to block SNS activity, led to a reduction in blood HSPC and myeloid populations. To explore the role of RA in atherogenesis we fed Ldlr-/- mice a high fat/high cholesterol diet for 14wks to stimulate lesion development. Mice were then switched to a normal chow diet for 3 weeks to allow lesion regression. Mice were injected with KBxN and treated with or without b-blockers. Mice injected with KBxN had impaired lesion regression which was prevented with b-blockers, likely due to a reduction in HSPC mobilisation and myeloid expansion. Therefore, targeting the SNS in patients with RA with b-blockers may reduce the risk for CVD.

Effect of oxidative stress in rostral ventrolateral medulla on sympathetic hyperactivity after traumatic brain injury.

Sympathetic hyperactivity occurs in a subgroup of patients after traumatic brain injury (TBI). The rostral ventrolateral medulla (RVLM) is a key region for the activity of sympathetic nervous system. Oxidative stress in the RVLM is proved to be responsible for the increased level of sympathetic activity in animal models of hypertension and heart failure. In this study, we investigated whether oxidative stress in the RVLM contributed to the development of sympathetic hyperactivity after TBI in rats. Model of diffuse axonal injury was induced using Sprague-Dawley rats, and level of mean arterial pressure (MAP) and plasma Norepinephrine (NE) was measured to evaluate the sympathetic activity. For the assessment of oxidative stress, expression of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) in the RVLM was determined. Microinjection of Tempol into the RVLM was performed to determine the effect of oxidative stress on sympathetic hyperactivity. According to the results, TBI led to elevated MAP and plasma NE in rats. It also induced a significantly increased level of ROS, MDA production and decreased level of SOD in the RVLM. The sympathetic activity, ROS, and MDA in the RVLM decreased significantly after microinjection of Tempol. Therefore, the present results suggested that oxidative stress in the RVLM was involved in the development of sympathetic hyperactivity following TBI.

Lavare Cycle Does Not Induce Pulsatility in CF-LVAD Patients

Purpose The Lavare cycle (LC) is a pre-programmed speed modulation algorithm (SMA) in the HeartWare continuous flow left ventricular assist device (HVAD) designed to increase ventricular and pump washout. We sought to determine whether the LC induced artificial pulsatility and alter sympathetic nervous system activity. Methods Ten HVAD patients were prospectively recruited. Patients were monitored for 24 hours using 3 devices and pulsatility metrics were calculated; 1) SphygmoCor 24-hour ambulatory oscillometric / tonometric blood pressure (BP) monitoring device was used to calculate pulse pressure (PP) and mean arterial pressure (MAP), 2) CDAS continuous pump data recorder was used to calculate a flow pulsatility index (PI), defined as (maximum - minimum flow)/(mean flow) and 3) Holter monitor (1000Hz) was used to calculate time domain measures of heart rate variability (HRV) to ascertain changes in sympathetic activity levels. Patients were monitored on two separate occasions, once with their LC on and once with it off. BP, flow and PI analyses were dichotomized for awake and asleep hours to account for diurnal variation in blood pressure and cardiac output. Results PP and MAP results were available for 9 patients, PI for 8 patients and HRV for 7 patients (table 1). There was no difference in PP, MAP or PI between the LC on and LC off groups. In terms of HRV, the LC on group had slightly higher heart rate (HR) compared to the LC off group (81.2 vs 78.7 bpm, p=0.028). There was no difference between groups in time domain measures of HRV (SDNN, standard deviation of normal-normal intervals; RMSSD root mean square of successive differences), markers of sympathetic and parasympathetic activity respectively. MAP was lower whilst asleep than awake (68.8 v 78.5, p=0.004), unaffected by LC. There were no differences between awake and asleep groups for PP, PI or mean flow (table 1). Conclusion LC is not associated with induced pulsatility or altered sympathetic activity in HVAD patients. MAP was lower in patients whilst asleep compared to when awake.