Vagus–brain communication in atherosclerosis-related inflammation: A neuroimmunomodulation perspective of CAD

Targeting IL-13 with tralokinumab normalizes type 2 inflammation in atopic dermatitis both early and at 2 years

BACKGROUND

Tralokinumab is a monoclonal antibody that specifically neutralizes interleukin (IL)-13, a key driver of skin inflammation and barrier abnormalities in atopic dermatitis (AD). This study evaluated early and 2-year impacts of IL-13 neutralization on skin and serum biomarkers following tralokinumab treatment in adults with moderate-to-severe AD.

METHODS

Skin biopsies and blood samples were evaluated from a subset of patients enrolled in the Phase 3 ECZTRA 1 (NCT03131648) and the long-term extension ECZTEND (NCT03587805) trials. Gene expression was assessed by RNA sequencing; protein expression was assessed by immunohistochemistry and immunoassay.

RESULTS

Tralokinumab improved the transcriptomic profile of lesional skin by Week 4. Mean improvements in the expression of genes dysregulated in AD were 39% at Week 16 and 85% at 2 years with tralokinumab, with 15% worsening at Week 16 with placebo. At Week 16, tralokinumab significantly decreased type 2 serum biomarkers (CCL17/TARC, periostin, and IgE), reduced epidermal thickness versus placebo, and increased loricrin coverage versus baseline. Two years of tralokinumab treatment significantly reduced expression of genes in the Th2 (IL4R, IL31, CCL17, and CCL26), Th1 (IFNG), and Th17/Th22 (IL22, S100A7, S100A8, and S100A9) pathways as well as increased expression of epidermal differentiation and barrier genes (CLDN1 and LOR). Tralokinumab also shifted atherosclerosis signaling pathway genes (SELE, IL-37, and S100A8) toward non-lesional expression.

CONCLUSION

Tralokinumab treatment improved epidermal pathology, reduced systemic markers of type 2 inflammation, and shifted expression of key AD biomarkers in skin towards non-lesional levels, further highlighting the key role of IL-13 in the pathogenesis of AD.

CLINICAL TRIAL REGISTRATION

NCT03131648, NCT03587805.

Autonomic Function in Obese Children and Adolescents: Systematic Review and Meta-Analysis

Background: Obesity is invariably accompanied by autonomic dysfunction, although data in pediatric populations are conflicting. Methods: We conducted a systematic review and meta-analysis of 12 studies (totaling 1102 participants) comparing obese and normal-weight subjects (5-18 years of age), defined as body mass index >95th or <85th percentile, respectively. Using a random-effects model, we report the standardized mean differences (SMD) of sympathetic and vagal indices of heart rate variability. Results: Autonomic dysfunction was present in the obesity group, based on the average SMD in the standard deviation of sinus intervals (at -0.5340), and on the ratio of low (LF)- to high (HF)-frequency spectra (at 0.5735). There was no difference in sympathetic activity, but the heterogeneity among the relevant studies weakens this result. SMD in HF (at 0.5876), in the root mean square of successive differences between intervals (at -0.6333), and in the number of times successive intervals exceeded 50 ms divided by the total number of intervals (at -0.5867) indicated lower vagal activity in the obesity group. Conclusions: Autonomic dysfunction is present in obese children and adolescents, attributed to lower vagal activity. Further studies are needed in various pediatric cohorts, placing emphasis on sympathetic activity.

Neuroimmunomodulation of adrenoblockers during liver cirrhosis: modulation of hepatic stellate cell activity

The sympathetic nervous system and the immune system are responsible for producing neurotransmitters and cytokines that interact by binding to receptors; due to this, there is communication between these systems. Liver immune cells and nerve fibres are systematically distributed in the liver, and the partial overlap of both patterns may favour interactions between certain elements. Dendritic cells are attached to fibroblasts, and nerve fibres are connected via the dendritic cell-fibroblast complex. Receptors for most neuroactive substances, such as catecholamines, have been discovered on dendritic cells. The sympathetic nervous system regulates hepatic fibrosis through sympathetic fibres and adrenaline from the adrenal glands through the blood. When there is liver damage, the sympathetic nervous system is activated locally and systemically through proinflammatory cytokines that induce the production of epinephrine and norepinephrine. These neurotransmitters bind to cells through α-adrenergic receptors, triggering a cellular response that secretes inflammatory factors that stimulate and activate hepatic stellate cells. Hepatic stellate cells are key in the fibrotic process. They initiate the overproduction of extracellular matrix components in an active state that progresses from fibrosis to liver cirrhosis. It has also been shown that they can be directly activated by norepinephrine. Alpha and beta adrenoblockers, such as carvedilol, prazosin, and doxazosin, have recently been used to reverse CCl₄-induced liver cirrhosis in rodent and murine models.KEY MESSAGESNeurotransmitters from the sympathetic nervous system activate and increase the proliferation of hepatic stellate cells.Hepatic fibrosis and cirrhosis treatment might depend on neurotransmitter and hepatic nervous system regulation.Strategies to reduce hepatic stellate cell activation and fibrosis are based on experimentation with α-adrenoblockers.

Role of Heart Rate Variability in the Association between Myocardial Infarction Severity and Post-Myocardial Infarction Distress

OBJECTIVE

Myocardial infarction (MI) results in mental health consequences, including depression and post-traumatic stress disorder (PTSD). The risk and protective factors of such mental consequences are not fully understood. This study examined the relation between MI severity and future mental health consequences and the moderating role of vagal nerve activity.

METHODS

In a reanalysis of data from the Myocardial Infarction-Stress Prevention Intervention (MI-SPRINT) study, 154 post-MI patients participated. MI severity was measured by the Killip Scale and by troponin levels. Depression and PTSD symptoms were assessed with valid questionnaires, both at 3 and 12 months. Vagal nerve activity was indexed by the heart rate variability (HRV) parameter of the root-mean square of successive R-R differences (RMSSD). Following multivariate analyses, the association between MI severity and distress was examined in patients with low and high HRV (RMSSD = 30 ms).

RESULTS

In the full sample, the Killip index predicted post-MI distress only at 3 months, while troponin predicted distress at 3- and 12-months post-MI. However, HRV moderated the effects of the Killip classification; Killip significantly predicted symptoms of depression and PTSD at 3- and 12-months post-MI, but only in patients with low HRV. Such moderation was absent for troponin.

CONCLUSION

MI severity (Killip classification) predicted post-MI depression and PTSD symptoms, but only in patients with low HRV, suggesting that the vagal nerve is a partial protective (moderating) factor in the relation between Killip score and post-MI distress.

Vagus nerve stimulation for cardiovascular diseases: Is there light at the end of the tunnel?

Autonomic dysfunction and chronic inflammation contribute to the pathogenesis and progression of several cardiovascular diseases (CVD), such as heart failure with preserved ejection fraction, atherosclerotic CVD, pulmonary arterial hypertension, and atrial fibrillation. The vagus nerve provides parasympathetic innervation to the heart, vessels, and lungs, and is also implicated in the neural control of inflammation through a neuroimmune pathway involving the spleen. Stimulation of the vagus nerve (VNS) can in principle restore autonomic balance and suppress inflammation, with potential therapeutic benefits in these diseases. Although VNS ameliorated CVD in several animal models, early human studies have demonstrated variable efficacy. The purpose of this review is to discuss the rationale behind the use of VNS in the treatment of CVD, to critically review animal and human studies of VNS in CVD, and to propose possible means to overcome the challenges in the clinical translation of VNS in CVD.

Gene Expression Analysis Suggests Immunological Changes of Peripheral Blood Monocytes in the Progression of Patients With Coronary Artery Disease

Objectives

To analyze the gene expression profile of peripheral blood monocytes in different stages of coronary artery disease (CAD) by transcriptome sequencing, and to explore potential genes and pathway involved in CAD pathogenesis.

Methods

According to the screening of coronary angiography and quality control of blood samples, eight intermediate coronary lesion patients were selected, then eight patients with acute myocardial infarction, and eight patients with normal coronary angiography were matched by age and gender. Transcriptomics sequencing was conducted for the peripheral blood monocytes of these 24 samples by using the Illumina HiSeq high-throughput platform. Then, differentially expressed genes (DEGs) were analyzed. Gene Ontology (GO) functional annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation, and protein-protein interaction (PPI) network were applied to annotate the potential functions of DEGs.

Results

Compared with the normal coronary angiography group, we identified a total of 169 DEGs in the intermediate coronary lesion group, which were significantly enriched in 59 GO terms and 17 KEGG pathways. Compared with the normal coronary angiography group, we found a total of 2,028 DEGs, which were significantly enriched in 311 GO terms and 20 KEGG pathways in the acute myocardial infarction group. The cross-comparison between normal versus intermediate coronary lesion group, and normal versus acute myocardial infarction group included 98 differential genes with 65 up regulated and 33 down regulated genes, which were significantly enriched in 46 GO terms and 10 KEGG pathways. During the progression of CAD, there was a significant up-regulated expression of CSF3, IL-1A, CCR7, and IL-18, and down-regulated expression of MAPK14. Besides GO items such as inflammatory response was significantly enriched, KEGG analysis showed the most remarkable enrichments in IL-17 signaling pathway and cytokine-cytokine receptor interactions.

Conclusions

Transcriptomics profiles vary in patients with different severity of CAD. CSF3, IL-1A, CCR7, IL-18, and MAPK14, as well as IL-17 signaling pathway and cytokine and cytokine receptor interaction signaling pathway related with inflammatory response might be the potential biomarker and targets for the treatment of coronary artery disease.

Slow-Paced Breathing and Autonomic Function in People Post-stroke

Purpose: To determine if acute slow breathing at 6 breaths/min would improve baroreflex sensitivity (BRS) and heart rate variability (HRV), and lower blood pressure (BP) in adults after stroke. Methods: Twelve individuals completed two randomized study visits where they performed a 15-min bout of breathing exercises at 6 breaths/min (slow) and at 12 breaths/min (control). Continuous BP and heart rate (HR) were measured throughout, and BRS, BRS response to elevations in blood pressure (BRSup), BRS response to depressions in blood pressure (BRSdown), and HRV were calculated and analyzed before (pre), during, and after (post) breathing exercises. Results: BRS increased from pre to post slow breathing by 10% (p = 0.012), whereas BRSup increased from pre to during slow breathing by 30% (p = 0.04). BRSdown increased from pre to post breathing for both breathing conditions (p < 0.05). HR (control: Δ - 4 ± 4; slow: Δ - 3 ± 4 beats/min, time, p < 0.01) and systolic BP (control: Δ - 0.5 ± 5; slow: Δ - 6.3 ± 8 mmHg, time, p < 0.01) decreased after both breathing conditions. Total power, low frequency power, and standard deviation of normal inter-beat intervals (SDNN) increased during the 6-breaths/min condition (condition × time, p < 0.001), whereas high frequency increased during both breathing conditions (time effect, p = 0.009). Conclusions: This study demonstrated that in people post-stroke, slow breathing may increase BRS, particularly BRSup, more than a typical breathing space; however, paced breathing at either a slow or typical breathing rate appears to be beneficial for acutely decreasing systolic BP and HR and increasing HRV.

Cannabidiol activation of vagal afferent neurons requires TRPA1

Vagal afferent neurons abundantly express excitatory transient receptor potential (TRP) channels, which strongly influence afferent signaling. Cannabinoids have been identified as direct agonists of TRP channels, including TRPA1 and TRPV1, suggesting that exogenous cannabinoids may influence vagal signaling via TRP channel activation. The diverse therapeutic effects of electrical vagus nerve stimulation also result from administration of the nonpsychotropic cannabinoid, cannabidiol (CBD); however, the direct effects of CBD on vagal afferent signaling remain unknown. We investigated actions of CBD on vagal afferent neurons, using calcium imaging and electrophysiology. CBD produced strong excitatory effects in neurons expressing TRPA1. CBD responses were prevented by removal of bath calcium, ruthenium red, and the TRPA1 antagonist A967079, but not the TRPV1 antagonist SB366791, suggesting an essential role for TRPA1. These pharmacological experiments were confirmed using genetic knockouts where TRPA1 KO mice lacked CBD responses, whereas TRPV1 knockout (KO) mice exhibited CBD-induced activation. We also characterized CBD-provoked inward currents at resting potentials in vagal afferents expressing TRPA1 that were absent in TRPA1 KO mice, but persisted in TRPV1 KO mice. CBD also inhibited voltage-activated sodium conductances in A-fiber, but not in C-fiber afferents. To simulate adaptation, resulting from chronic cannabis use, we administered cannabis extract vapor daily for 3 wk. Cannabis exposure reduced the magnitude of CBD responses, likely due to a loss of TRPA1 signaling. Together, these findings detail a novel excitatory action of CBD at vagal afferent neurons, which requires TRPA1 and may contribute to the vagal mimetic effects of CBD and adaptation following chronic cannabis use.NEW & NOTEWORTHY CBD usage has increased with its legalization. The clinical efficacy of CBD has been demonstrated for conditions including some forms of epilepsy, depression, and anxiety that are also treatable by vagus nerve stimulation. We found CBD exhibited direct excitatory effects on vagal afferent neurons that required TRPA1, were augmented by TRPV1, and attenuated following chronic cannabis vapor exposure. These effects may contribute to vagal mimetic effects of CBD and adaptation after chronic cannabis use.

Is cervical region tightness related to vagal function and stomach symptoms?

The vagal nerve is a cranial nerve that carries mainly parasympathetic fibers (average 75%) with both sensory and motor functions. The vagal nerve contains a complex neuro-endocrine-immune network. The majority, at least 66%, of the gastric myenteric neurons receive direct cholinergic excitatory stimulation from the pre-enteric vagal nerve. Changes in vagal function may cause stomach problems, although the mechanisms that change the vagal function have not yet been fully illuminated. Considering the course of the vagal nerve in the cervical region, it is thought that conditions such as stiffness, tightness and decreased elasticity in this region may compress the vagal nerve andmay affect vagal function. According to this hypothesis, neuroinflammation and hyperalgesia may occur in the vagal nerve under mechanical pressure, resulting in increased complaints of pain and burning in the stomach increases. However, as the vagal nerve has various effects on the motility of the stomach and vagal dysfunction affects the motor function of the stomach, relaxation techniques applied to the soft tissues of the cervical region will provide mechanical relief in the nerve. Thus, the vagal nerve will be decompressed and be able to function optimally. According to our clinical observations, in patients whose soft tissues in the cervical region are relaxed, gastric symptoms are decreased. Based on research results and clinical experience, cervical region tightness can be considered to cause stomach problems through the vagal nerve, and soft tissue relaxation of the cervical region can be a promising treatment method for stomach symptoms.

The Role of Cardiac Ganglia in the Prevention of Coronary Atherosclerosis: An Analytical Examination of Cholesterol-fed Rabbits

Background

The heart is innervated by the autonomic nervous system, which contributes to the control of the heart’s rhythm and coronary circulation. It has been suggested that the cardiac fibers of the vagus nerve play important roles in controlling circulatory functions and in protecting against atherosclerotic pathologies in coronary arteries.

Aims

To investigate the presence of atherosclerotic differences in the coronary arteries of cholesterol-fed rabbits by measuring the density of cardiac ganglia neurons.

Study Design

Animal experiment.

Methods

This study was conducted using 45 male rabbits. Over a period of 16 weeks, they were kept on an atherogenic diet of water ad libitum and high fat (8.6%) containing saturated fatty acids with 205 mg/kg of cholesterol (1%) per day. Then, their hearts were removed and examined by histopathological methods. Atherosclerotic plaques of the main coronary arteries were examined using the Cavalieri method. Atherosclerosis index values (AIVs) were estimated as the wall surface area/plaque surface area, and the results were analyzed with the Kruskal-Wallis and Mann-Whitney U tests.

Results

While the average atherosclerosis index value was estimated to be ≤8% in 21 animals, the atherosclerosis index value was 9-20% in animals with minor plaque detection (n=11) and ≥20% in animals with major plaque detection (n=10). Increased atherosclerosis index values were more common in animals with low neuron densities than in animals with high neuron densities (p<0.017).

Conclusion

The low neuron density of the cardiac ganglia in cholesterol-fed rabbits is associated with an increased atherosclerotic plaque incidence and volume.

Effect of vagus nerve stimulation on tissue damage and function loss in a mouse myocardial ischemia-reperfusion model

OBJECTIVES

In cardiac ischemia, acute inflammatory responses further increase the detrimental effect on myocardial tissue. Since vagus nerve stimulation (VS) attenuates inflammatory responsiveness this study examines the effect of VS on myocardial damage development in a cardiac ischemia-reperfusion (IR) mouse model.

METHODS

54 male C57Bl/6j mice were subjected to an IR procedure with or without prior VS. The effects on inflammatory responsiveness, infarct size, cardiac function, neutrophils, lymphocytes and vascular endothelial growth factor (VEGF) in the infarcted myocardium were measured at 48 h after intervention. Group results were compared with unpaired Mann-Whitney or Kruskall-Wallis test.

RESULTS

A significant decrease in inflammatory responsiveness was not verified by decreased TNFα levels in blood from VS and IR treated mice. The percentage infarct size over area at risk was smaller in the group with VS + IR compared with IR (22.4 ± 10.2% vs 37.6 ± 9.0%, p = 0.003). The degree of the reduction in cardiac function was not different between the IR groups with or without VS and no group differences were found in amounts of neutrophils, CD3+ lymphocytes and VEGF in the reperfused mouse heart.

CONCLUSION

The present study does not provide clear evidence of a reducing role for VS on cardiac function loss. This could mean that VS has a less inhibiting effect on myocardial inflammation than may be expected from the literature.

Current Directions in the Auricular Vagus Nerve Stimulation I - A Physiological Perspective

Electrical stimulation of the auricular vagus nerve (aVNS) is an emerging technology in the field of bioelectronic medicine with applications in therapy. Modulation of the afferent vagus nerve affects a large number of physiological processes and bodily states associated with information transfer between the brain and body. These include disease mitigating effects and sustainable therapeutic applications ranging from chronic pain diseases, neurodegenerative and metabolic ailments to inflammatory and cardiovascular diseases. Given the current evidence from experimental research in animal and clinical studies we discuss basic aVNS mechanisms and their potential clinical effects. Collectively, we provide a focused review on the physiological role of the vagus nerve and formulate a biology-driven rationale for aVNS. For the first time, two international workshops on aVNS have been held in Warsaw and Vienna in 2017 within the framework of EU COST Action "European network for innovative uses of EMFs in biomedical applications (BM1309)." Both workshops focused critically on the driving physiological mechanisms of aVNS, its experimental and clinical studies in animals and humans, in silico aVNS studies, technological advancements, and regulatory barriers. The results of the workshops are covered in two reviews, covering physiological and engineering aspects. The present review summarizes on physiological aspects - a discussion of engineering aspects is provided by our accompanying article (Kaniusas et al., 2019). Both reviews build a reasonable bridge from the rationale of aVNS as a therapeutic tool to current research lines, all of them being highly relevant for the promising aVNS technology to reach the patient.

Association Between Systemic Inflammation, Carotid Arteriosclerosis, and Autonomic Dysfunction

Systemic inflammation is associated with arteriosclerotic disease progression and worse stroke outcome in patients with carotid arteriosclerotic disease. We hypothesize that systemic inflammation is mediated by impaired carotid baroreceptor and chemoreceptor function induced by carotid arteriosclerosis rather than by the generalized inflammatory arteriosclerotic process.Heart rate variability (HRV), serum levels of inflammatory markers, demographic and life style factors, and concomitant diseases with potential impact on systemic inflammation were determined in 105 patients with asymptomatic carotid stenosis of varying degree. Multivariate linear regression analyses were performed to ascertain independent determinants of carotid stenosis severity, autonomic function, and inflammation.Systemic inflammation (C-reactive protein, beta = .255; P = .014), age (beta = .232; P < .008), and arterial hypertension (beta = .206; P = .032) were associated with carotid stenosis severity. Only carotid stenosis severity and not generalized arteriosclerotic disease, concomitant diseases (arterial hypertension, diabetes mellitus, dyslipidemia, hypothyroidism), life style factors (smoking, obesity), or age was associated with a reduction in vagal tone (HRV HF band power beta = - .193; P < 0.049). Systemic inflammation was related to a reduction in vagal tone (HRV HF band power, beta = - .214; P = .031), and not to generalized arteriosclerotic disease, concomitant diseases (arterial hypertension, diabetes mellitus, dyslipidemia), life style factors (smoking, obesity), and age.In conclusion, systemic inflammation is associated with carotid rather than with generalized arteriosclerotic disease. The association between systemic inflammation and carotid arteriosclerosis is mediated by a reduction in vagal tone which indicates a major role of carotid arteriosclerosis-mediated autonomic dysfunction in the pathogenesis of systemic inflammation in arteriosclerotic disease.

A long-term perspective on cardiovascular job stress research

This review provides perspectives on cardiovascular occupational stress research since the 1960s until now. The author argues for closer links between basic science and clinical follow‐up examinations of patients. In an excellent way urinary excretion of adrenaline and noradrenaline during wake hours mirrors day to day or week to week variations in sympathomedullary activity which could be related to variations in the patient's and cardiovascular and psychosocial situation. Modern methods for following variations over time in heart contractility should also be related to the patients' psychosocial situation. In addition the author argues for more extensive use of the increasing knowledge regarding regeneration and vagal activity in relation to variations in job conditions and development or prevention of cardiovascular disease.

Neutrophil count as the centerpiece in the joined association networks of inflammatory and cell damage markers, and neuroendocrine stress markers in patients with stable angina pectoris following stenting

Objective

The primary aim of this study was to examine whether markers of cell damage and of the psycho-neuroendocrino-inflammatory/immune (PNI) system could be associated in patients with stable coronary artery disease (CAD) on the next day following percutaneous coronary intervention (PCI).

Materials and methods

Blood samples of 23 patients (18 men and five women, mean age 62.9 ± 10.6 years), were collected immediately before (pre-PCI), immediately after (post-PCI), and on the day following PCI (1d-PCI). Lactoferrin, LL-37 and interleukin-6 (IL-6) were assayed in plasma, in addition to cortisol and chromogranin A (CgA), as well as CK, ASAT and ALAT. Total and differential leukocyte counts were also analysed.

Results

At all the three time points, the monocyte fractions, the monocyte-to-lymphocyte and the neutrophil-to-lymphocyte ratios and CgA levels were elevated. We detected significant peri-procedural changes in the plasma levels of our PNI markers: IL-6 (p<0.05), lactoferrin, LL-37 (both: p <0.0001), CgA, (p<0.05), and cortisol (p<0.01). On the first day after PCI, highly significant associations were found of ASAT with IL-6 and neutrophil count (both: r>0.75, p<0.0001), and of CgA with neutrophil count and monocyte count (both: r>0.79, p<0.0001); furthermore, cortisol was also associated with neutrophil count (r>0.7, p<0.0001).

Conclusions

The findings suggest that myocardial damage could correlate not only with an inflammatory reaction but, via neutrophil count, also with increased level of stress in stable CAD after PCI. Furthermore, 1d-PCI neutrophil count may serve as an easy-to-obtain integrative PNI measure in stable CAD.

The Vagus Nerve Can Predict and Possibly Modulate Non-Communicable Chronic Diseases: Introducing a Neuroimmunological Paradigm to Public Health

Global burden of diseases (GBD) includes non-communicable conditions such as cardiovascular diseases, cancer and chronic obstructive pulmonary disease. These share important behavioral risk factors (e.g., smoking, diet) and pathophysiological contributing factors (oxidative stress, inflammation and excessive sympathetic activity). This article wishes to introduce to medicine and public health a new paradigm to predict, understand, prevent and possibly treat such diseases based on the science of neuro-immunology and specifically by focusing on vagal neuro-modulation. Vagal nerve activity is related to frontal brain activity which regulates unhealthy lifestyle behaviors. Epidemiologically, high vagal activity, indexed by greater heart rate variability (HRV), independently predicts reduced risk of GBD and better prognosis in GBD. Biologically, the vagus nerve inhibits oxidative stress, inflammation and sympathetic activity (and associated hypoxia). Finally, current non-invasive methods exist to activate this nerve for neuro-modulation, and have promising clinical effects. Indeed, preliminary evidence exists for the beneficial effects of vagal nerve activation in diabetes, stroke, myocardial infarction and possibly cancer. Thus, we propose to routinely implement measurement of HRV to predict such GBD in populations, and to test in randomized controlled trials effects of non-invasive vagal nerve activation on prevention and treatment of GBD, reflecting possible neuro-modulation of health.

Endothelial stem cells attenuate cardiac apoptosis via downregulating cardiac microRNA-146a in a rat model of coronary heart disease

Coronary artery disease (CAD) is one of the main causes of hospitalization worldwide and has high morbidity. It has previously been demonstrated that stem cells serve an important role in improving myocardial function. MicroRNA (miRNA)-146a downregulation has been reported to inhibit vascular smooth muscle cell apoptosis in a rat model of coronary heart disease. The aim of the present study was to investigate the mechanisms underlying the effects of endothelial stem cell (ESC)-derived paracrine factors and cardiac miRNAs in CAD. Acute myocardial infarction was induced in 20 rats. Autologous ESCs (n=10; experimental group) or PBS (n=10; control group) were injected in the border zone. Reverse transcription-quantitative polymerase chain reaction, ELISA and immunohistochemistry assays were performed to analyze the therapeutic effects of ESCs in rats with coronary heart disease rats. Serum interleukin (IL)-1, IL-17 and tumor necrosis factor-α were reduced in the experimental group compared with control rats, as was the number of circulating proatherogenic cells. The results demonstrated that ESC transplantation markedly downregulated miRNA-146a expression and decreased apoptosis in the myocardium compared with the control group. Rats in the experimental group also had higher levels of vascular endothelial growth factor compared with the control group. In addition, it was demonstrated that miRNA-146 knockdown reduced cardiac apoptosis and increased VEGF expression. Furthermore, the infarct area in the border zone or rats with CAD was reduced in the experimental group compared with the control group. In conclusion, these results suggest that ESC transplantation may improve cardiac function via downregulating miR-146a, which may be have potential as a treatment for CAD.

Neurodevelopment impact of CO2-pneumoperitoneum in neonates: experimental study in a rat model

BACKGROUND

Laparoscopy is becoming more common in neonates. However, concerns remain about the impact of the carbon-dioxide (CO₂)-insufflation over the neonatal brain. We aim to evaluate the peripheral (serum) and central (cerebrospinal fluid [CSF]) cytokine response after neonatal CO₂-pneumoperitoneum and its impact over neurodevelopmental milestones acquisition and long-term behavioral outcomes.

MATERIALS AND METHODS

Rats were subjected to a systematic assessment of neurodevelopmental milestones between postnatal day 1 (PND 1) and PND 21. At PND 10, neonatal rats were anesthetized, mechanically ventilated, and exposed to different pressures and times of abdominal CO₂-insufflation. Immediately after pneumoperitoneum, corticosterone was analyzed in serum. Twenty-four hours after intervention, serum and CSF were collected to assess inflammatory response (interleukin [IL]-10, IL-1β, tumor necrosis factor [TNF]-α, and interferon [IFN]-γ). In adulthood, animals from each group were submitted to several tests to assess different behavioral domains (locomotion, anxiety, mood, and cognition).

RESULTS

The antiinflammatory cytokine IL-10 was significantly increased in CSF in CO₂-insufflated groups, with no other significant changes in the other biomarkers. Acquisition of neurodevelopmental milestones was maintained in all studied groups. No significant differences were observed in adult behavior in the different CO₂-insufflation conditions.

CONCLUSIONS

Neonatal CO₂-pneumoperitoneum does not seem to have any negative impact on neurodevelopment or induce behavioral alterations in adulthood. Minimally invasive surgery results in a central antiinflammatory profile, and further studies on the functional consequences of these phenomena are needed.

White blood cell inflammatory markers are associated with depressive symptoms in a longitudinal study of urban adults

Total white blood cell count (TWBCC) and percentage (%) composition of lymphocytes (PL) or neutrophils (PN) are linked to mid- and late-life depression, though sex-specific temporal relationships between those inflammatory markers and depressive symptoms remain unclear. The association between inflammation and depressive symptoms in longitudinal data on ethnically and socioeconomically diverse urban adults was examined with two hypotheses. In hypothesis 1, we examined the relationship between TWBCC, PL and PN with change in level of depressive symptoms from baseline to follow-up, stratifying by sex. In hypothesis 2, we examined reverse causality, by testing the relationship of depressive symptoms with change in TWBCC, PL and PN. Multiple linear mixed-effects regression models were performed to examine both the hypotheses. The sample sizes of participants (n) and repeated observations (n') were: Hypothesis 1 (n=2009; n'=3501); Hypothesis 2 (n=2081; n'=3560). Among key findings (Hypothesis 1), in women, higher TWBCC was linked to a faster increase in depressive symptom total score (γ1112±s.e.: +0.81±0.28, P=0.003), with a slower increase over time in the positive affect subdomain coupled with faster increases in depressed affect and somatic complaints. Among women, baseline score on somatic complaints was positively associated with low PN (γ01a=+1.61±0.48, P<0.001) and high PL (γ01a=+1.16±0.45, P=0.011), whereas baseline score on positive affect was inversely related to higher PL (γ01a=-0.69±0.28, P=0.017). Results among men indicated that there was a positive cross-sectional relationship between low TWBCC and depressive symptoms, depressed affect and an inverse cross-sectional relationship with positive affect. However, over time, a low TWBCC in men was linked to a higher score on positive affect. There was no evidence of a bi-directional relationship between WBC parameters and depressive symptoms (Hypothesis 2). In sum, TWBCC and related markers were linked to depressive symptoms, mostly among women. Further longitudinal studies are needed to replicate this sex-specific association.

Higher vagal activity as related to survival in patients with advanced breast cancer: an analysis of autonomic dysregulation

OBJECTIVE

High levels of high-frequency heart rate variability (HF-HRV), related to parasympathetic-nervous-system functioning, have been associated with longer survival in patients with myocardial infarction and acute trauma and in patients undergoing palliative care. From animal studies linking higher vagal activity with better immune system functioning and reduced metastases, we hypothesized that higher HF-HRV would predict longer survival in patients with metastatic or recurrent breast cancer (MRBC).

METHODS

Eighty-seven patients with MRBC participated in a laboratory task including a 5-minute resting baseline electrocardiogram. HF-HRV was computed as the natural logarithm of the summed power spectral density of R-R intervals (0.15-0.50 Hz). In this secondary analysis of a study testing whether diurnal cortisol slope predicted survival, we tested the association between resting baseline HF-HRV on survival using Cox proportional hazards models.

RESULTS

A total of 50 patients died during a median follow-up of 7.99 years. Higher baseline HF-HRV predicted significantly longer survival, with a hazard ratio of 0.75 (95% confidence interval = 0.60-0.92, p = .006). Visceral metastasis status and baseline heart rate were related to both HF-HRV and survival. However, a combination of HF-HRV and heart rate further improved survival prediction, with a hazard ratio of 0.64 (95% confidence interval = 0.48-0.85, p = .002).

CONCLUSIONS

Vagal activity of patients with MRBC strongly predicted their survival, extending the known predictive window of HF-HRV in cancer beyond palliative care. Vagal activity can be altered by behavioral, pharmacological, and surgical interventions and may be a promising target for extending life expectancy in patients with metastasizing cancer.

Association of plasma IL-6 and Hsp70 with HRV at different levels of PAHs metabolites

BACKGROUND

Exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with reduced heart rate variability (HRV), a strong predictor of cardiovascular diseases, but the mechanism is not well understood.

OBJECTIVES

We hypothesized that PAHs might induce systemic inflammation and stress response, contributing to altered cardiac autonomic function.

METHODS

HRV indices were measured using a 3-channel digital Holter monitor in 800 coke oven workers. Plasma levels of interleukin-6 (IL-6) and heat shock protein 70 (Hsp70) were determined using ELISA. Twelve urinary PAHs metabolites (OH-PAHs) were measured by gas chromatography-mass spectrometry.

RESULTS

We found that significant dose-dependent relationships between four urinary OH-PAHs and IL-6 (all Ptrend<0.05); and an increase in quartiles of IL-6 was significantly associated with a decrease in total power (TP) and low frequency (LF) (Ptrend = 0.014 and 0.006, respectively). In particular, elevated IL-6 was associated in a dose-dependent manner with decreased TP and LF in the high-PAHs metabolites groups (all Ptrend<0.05), but not in the low-PAHs metabolites groups. No significant association between Hsp70 and HRV in total population was found after multivariate adjustment. However, increased Hsp70 was significantly associated with elevated standard deviation of NN intervals (SDNN), TP and LF in the low-PAHs metabolites groups (all Ptrend<0.05). We also observed that both IL-6 and Hsp70 significantly interacted with multiple PAHs metabolites in relation to HRV.

CONCLUSIONS

In coke oven workers, increased IL-6 was associated with a dose-response decreased HRV in the high-PAHs metabolites groups, whereas increase of Hsp70 can result in significant dose-related increase in HRV in the low-PAHs metabolites groups.

Chronic functional bowel syndrome enhances gut-brain axis dysfunction, neuroinflammation, cognitive impairment, and vulnerability to dementia

The irritable bowel syndrome (IBS) is a common chronic functional gastrointestinal disorder world wide that lasts for decades. The human gut harbors a diverse population of microbial organisms which is symbiotic and important for well being. However, studies on conventional, germ-free, and obese animals have shown that alteration in normal commensal gut microbiota and an increase in pathogenic microbiota-termed "dysbiosis", impact gut function, homeostasis, and health. Diarrhea, constipation, visceral hypersensitivity, and abdominal pain arise in IBS from the gut-induced dysfunctional metabolic, immune, and neuro-immune communication. Dysbiosis in IBS is associated with gut inflammation. Gut-related inflammation is pivotal in promoting endotoxemia, systemic inflammation, and neuroinflammation. A significant proportion of IBS patients chronically consume alcohol, non-steroidal anti-inflammatories, and fatty diet; they may also suffer from co-morbid respiratory, neuromuscular, psychological, sleep, and neurological disorders. The above pathophysiological substrate is underpinned by dysbiosis, and dysfunctional bidirectional "Gut-Brain Axis" pathways. Pathogenic gut microbiota-related systemic inflammation (due to increased lipopolysaccharide and pro-inflammatory cytokines, and barrier dysfunction), may trigger neuroinflammation enhancing dysfunctional brain regions including hippocampus and cerebellum. These as well as dysfunctional vago-vagal gut-brain axis may promote cognitive impairment. Indeed, inflammation is characteristic of a broad spectrum of neurodegenerative diseases that manifest demntia. It is argued that an awareness of pathophysiological impact of IBS and implementation of appropriate therapeutic measures may prevent cognitive impairment and minimize vulnerability to dementia.

Immune dysregulation and autoimmunity in bipolar disorder: Synthesis of the evidence and its clinical application

OBJECTIVE

Increasing evidence suggests that inflammation and immune dysregulation play an important role in the pathogenesis of bipolar disorder. Because the brain can be affected by various autoimmune processes, it is possible that some psychiatric disorders may have an autoimmune basis.

METHOD

This article reviews the literature on peripheral and central immune dysregulation and autoimmunity in bipolar disorder. The mechanisms of the innate and adaptive immune systems in the pathophysiology of bipolar disorder are explored. The clinical features and pathogenesis of neuropsychiatric systemic lupus erythematosus, anti-NMDA encephalitis, and Hashimoto's encephalopathy are summarized.

RESULTS

Neuroinflammation and peripheral immune dysregulation may play a role in the pathophysiology of bipolar disorder. This involves a complex interaction between immune cells of the central nervous system and periphery resulting in cellular damage through mechanisms involving excitotoxicity, oxidative stress, and mitochondrial dysfunction. Neuropsychiatric systemic lupus erythematosus, anti-NMDA encephalitis, and Hashimoto's encephalopathy are important differentials for a psychiatrist to consider when suspecting autoimmune encephalopathy.

CONCLUSIONS

The link between immune dysregulation, autoimmunity, and bipolar disorder may be closer than previously thought. Psychiatrists should be vigilant for autoimmunity in presentations of bipolar disorder due to its high morbidity and therapeutic implications. Advances in neuroimaging and biomarker identification related to immune dysregulation and neuroinflammation will contribute to our knowledge of the pathophysiology of bipolar disorder.

Depressive symptoms and white blood cell count in coronary heart disease patients: prospective findings from the Heart and Soul Study

BACKGROUND

Depression has been associated with elevated white blood cell (WBC) count - indicative of systemic inflammation - in cross-sectional studies, but no longitudinal study has evaluated whether depressive symptoms predict subsequent WBC count or vice versa. We sought to evaluate the bidirectional association between depressive symptoms and WBC count in patients with coronary heart disease (CHD).

METHODS

Depressive symptoms were assessed at baseline and annually during 5 consecutive years of follow-up in 667 outpatients with stable CHD from the Heart and Soul Study. The presence of significant depressive symptoms was defined as a score of ≥10 on the Patient Health Questionnaire (PHQ-9) at one or more assessments. WBC count was measured in blood samples collected at baseline and after 5 years of follow-up.

RESULTS

Of the 667 participants, 443 (66%) had no depressive symptoms (PHQ-9<10), 86 (13%) had depressive symptoms (PHQ-9≥10) at 1 assessment, and 138 (21%) had depressive symptoms at 2 or more annual assessments. Across the three groups, participants with recurrent depressive symptoms had higher WBC levels after 5 years of follow-up (p<.001). This relationship was essentially unchanged after adjustment for demographics, traditional cardiovascular risk factors, cardiac disease severity, inflammatory cytokine levels, and health behaviors (p=.009). Baseline WBC count was not associated with subsequent depressive symptoms (p=.18).

CONCLUSIONS

Depressive symptoms independently predicted higher subsequent WBC count in patients with stable CHD, but baseline WBC count did not predict subsequent depressive symptoms. These findings support a unidirectional relationship in which depression is a risk-factor for inflammation.

Changes in serum and cerebrospinal fluid cytokines in response to non-neurological surgery: an observational study

Background

Surgery launches an inflammatory reaction in the body, as seen through increased peripheral levels of cytokines and cortisol. However, less is known about perioperative inflammatory changes in the central nervous system (CNS).

Our aim was to compare inflammatory markers in serum and cerebrospinal fluid (CSF) before and after surgery and evaluate their association with measures of blood–brain barrier (BBB) integrity.

Methods

Thirty-five patients undergoing knee arthroplastic surgery with spinal anesthesia had CSF and serum samples drawn before, after and on the morning following surgery. Cytokines and albumin in serum and CSF and cortisol in CSF were assessed at all three points.

Results

Cytokines and cortisol were significantly increased in serum and CSF after surgery (Ps <0.01) and CSF increases were greater than in serum. Ten individuals had an increased cytokine response and significantly higher CSF/serum albumin ratios (Ps <0.01), five of whom had albumin ratios in the pathological range (>11.8). Serum and CSF levels of cytokines were unrelated, but there were strong correlations between CSF IL-2, IL-10 and IL-13, and albumin ratios (Ps <0.05) following surgery.

Conclusion

Cytokine increases in the CNS were substantially greater than in serum, indicating that the CNS inflammatory system is activated during peripheral surgery and may be regulated separately from that in the peripheral body. CSF cytokine increase may indicate sensitivity to trauma and is linked to BBB macromolecular permeability.

Baroreflex sensitivity in asymptomatic coronary atherosclerosis

BACKGROUND

Baroreflex sensitivity (BRS) reflects the effectiveness of cardiac parasympathetic regulation. BRS becomes impaired in stable coronary artery disease (CAD) and after myocardial infarction and carries prognostic information in these patients. Whether impaired BRS is found already in asymptomatic subjects, with subclinical coronary atherosclerosis, has remained elusive.

METHODS

The relationship between BRS and coronary atherosclerosis was evaluated in 31 subjects with high familial risk for CAD but without evidence of angina pectoris or myocardial ischaemia. Single photon emission tomography was performed with (99m) Tc-sestamibi to rule out myocardial perfusion defects at rest and during exercise. BRS was assessed by phenylephrine technique. Coronary atherosclerosis was analysed by quantitative coronary angiography (QCA). Percentage of diameter stenosis (PDS) was calculated separately for LAD, LCX, RCA coronary arteries as well as for proximal (PROX), middle (MID) and distal (DIST) coronary artery regions; and for all coronary artery regions (global PDS).

RESULTS

Baroreflex sensitivity averaged 7·8 ± 5·4 ms mmHg(-1) . BRS showed inverse correlation to PDS of the proximal coronary artery segments (r = -0·315; P<0·05) and with the most severe single coronary artery stenosis (r = -0·374; P<0·05). Five (16%) subjects had BRS ≤ 3 ms mmHg(-1) . They had more severe PDS of proximal coronary artery segment than subjects with BRS > 3 ms mmHg(-1) (24 ± 7% versus 13 ± 11%, P<0·05, respectively).

CONCLUSIONS

Impairment of BRS was found to be associated with the severity of subclinical coronary atherosclerosis in healthy asymptomatic subjects with familial risk of CAD. Asymptomatic subjects with severely blunted BRS may have advanced coronary atherosclerosis.

Cytokine levels as potential biomarkers for predicting the development of posttraumatic stress symptoms in casualties of accidents

BACKGROUND

Traumatic injuries are usually associated with increased secretion of pro-inflammatory cytokines, and are sometimes followed by the development of acute stress symptoms (ASS) and posttraumatic stress symptoms (PTSS).

AIMS

To measure serum pro- and anti-inflammatory cytokines in accident casualties and to associate it with ASS at hospitalization, and with PTSS 1 month later.

METHODS

Participants were 48 patients, aged 20-60, hospitalized following various orthopedic injuries including bone fractures, and 13 healthy volunteers matched for gender. At hospitalization (Time 1), 30 ml heparinized venous blood were drawn and cytokines levels in serum were assessed; participants filled out the Acute Stress Disorder Inventory (ASDI), COPE, and injury-related questionnaires. One month later (Time 2), 26 participants filled out the Posttraumatic Disorder Symptom Scale (PDS).

RESULTS

High serum levels of IL-6, IL-8, and TGF-beta and low levels of serum IL-4 and IL-10 were found in injured patients as compared with controls, When controlling for age and severity of injury in the regression analysis, higher levels of IL-6 and IL-8 and lower TGF-beta were predicted by higher ASS and higher use of and emotion-focused coping. Higher PTSS scores at Time 2 were predicted by higher levels of IL-8, lower levels of TGF-beta, and higher ASS measured at Time 1.

CONCLUSIONS

High levels of the pro-inflammatory cytokine IL-6 and IL-8 and lower levels of the regulatory cytokine TGF-beta should be further assessed as a possible risk factor or a bio-marker of PTSS in accident casualties.

Decrease in depression symptoms is associated with longer survival in patients with metastatic breast cancer: a secondary analysis

PURPOSE

Numerous studies have examined the comorbidity of depression with cancer, and some have indicated that depression may be associated with cancer progression or survival. However, few studies have assessed whether changes in depression symptoms are associated with survival.

METHODS

In a secondary analysis of a randomized trial of supportive-expressive group therapy, 125 women with metastatic breast cancer (MBC) completed a depression symptom measure (Center for Epidemiologic Studies-Depression Scale [CES-D]) at baseline and were randomly assigned to a treatment group or to a control group that received educational materials. At baseline and three follow-up points, 101 of 125 women completed a depression symptom measure. We used these data in a Cox proportional hazards analysis to examine whether decreasing depression symptoms over the first year of the study (the length of the intervention) would be associated with longer survival.

RESULTS

Median survival time was 53.6 months for women with decreasing CES-D scores over 1 year and 25.1 months for women with increasing CES-D scores. There was a significant effect of change in CES-D over the first year on survival out to 14 years (P = .007) but no significant interaction between treatment condition and CES-D change on survival. Neither demographic nor medical variables explained this association.

CONCLUSION

Decreasing depression symptoms over the first year were associated with longer subsequent survival for women with MBC in this sample. Further research is necessary to confirm this hypothesis in other samples, and causation cannot be assumed based on this analysis.

Heart rate variability and biomarkers of systemic inflammation in patients with stable coronary heart disease: findings from the Heart and Soul Study

BACKGROUND

Chronic low-grade systemic inflammation is a key component in atherogenesis. Decreased heart rate variability (HRV), a strong predictor of cardiovascular events, has been associated with elevations in circulating levels of C-reactive protein (CRP), interleukin (IL)-6, and fibrinogen in apparently healthy individuals. We investigated whether decreased HRV is associated with inflammatory markers in patients with coronary heart disease (CHD).

METHODS

We studied the relationship between HRV and CRP, IL-6, and fibrinogen in 862 outpatients with CHD. All participants provided fasting blood samples and underwent 24-h ambulatory monitoring to assess time-domain measures of HRV (MeanNN, SDNN, SDANN, and RMSSD). Regression analyses were adjusted for age, sex, ethnicity, body mass index, smoking, diabetes, beta blocker use, and cardiopulmonary history.

RESULTS

MeanNN, SDNN, and SDANN were significantly and inversely associated with CRP and IL-6 levels in age-adjusted models and after adjustment for all covariates (p ≤ 0.02). MeanNN, SDNN, and SDANN were also inversely associated with fibrinogen levels in age-adjusted models (p < 0.03), but not significantly so in multivariable-adjusted models. Reduced vagal modulation of heart rate (RMSSD) was not significantly associated with any inflammatory measures.

CONCLUSIONS

Reduced cardiac autonomic control is associated with increased systemic inflammation in patients with stable CHD. This relationship was largely independent of important covariates.

Anger, suppressed anger, and risk of adverse events in patients with coronary artery disease

Anger is associated with cardiovascular stress reactivity; however, little is known about the effect of suppressed anger in patients with coronary artery disease (CAD). We examined whether patients with CAD who suppress their anger are at risk of adverse events. At baseline, 644 patients with CAD completed measures of anger, anger-in (reluctance to express anger), and Type D personality (tendency to experience distress and to be inhibited). The combination of high anger and anger-in scores was used to identify the presence of suppressed anger. The end points were major adverse cardiac events (a composite of death, myocardial infarction, and revascularization) and cardiac death/myocardial infarction. After an average follow-up of 6.3 years (range 5 to 10), 126 patients (20%) had experienced a major adverse cardiac event, and 59 (9%) had experienced cardiac death or myocardial infarction. Anger (p = 0.009) and suppressed anger (p = 0.011) were associated with future major adverse cardiac events, but these associations were no longer significant after adjustment for clinical characteristics. However, suppressed anger remained associated with the more rigorous end point of cardiac death or myocardial infarction (odds ratio 2.87, 95% confidence interval 1.15 to 7.15, p = 0.024) after controlling for decreased systolic function, poor exercise tolerance, extent of CAD, and revascularization. Anger alone was not independently associated with this end point. Patients with a Type D personality had a fourfold rate of suppressed anger, and an adjustment for a Type D personality attenuated the observed association between suppressed anger and adverse cardiac events. In conclusion, patients with CAD who suppress their anger were at increased risk of adverse cardiac events, and this was accounted for by individual differences in Type D personality.

Lower-leg symptoms in peripheral arterial disease are associated with anxiety, depression, and anhedonia

Patients with peripheral arterial disease (PAD) report diverse clinical manifestations that are not always consistent with classic intermittent claudication. We examined the degree to which atypical exertional leg symptoms, intermittent claudication, and exertional leg symptoms that begin at rest were associated with mood states such as anxiety, depressive symptoms, and anhedonia (i.e. lack of positive affect). A cohort of consecutive PAD patients (n = 628) from the Erasmus Medical Center, Rotterdam, The Netherlands, completed the Hospital Anxiety and Depression Scale and the San Diego Claudication questionnaire. The ankle-brachial index and clinical factors were assessed in all patients at baseline. Anxiety was present in 29%, depressive symptoms in 30%, and anhedonia in 28% of patients. Pain at rest was independently associated with anxiety, depressive symptoms, and anhedonia (ORs between 2.5 and 4.0, p </= 0.001), while there was no relationship between intermittent claudication and mood states. Patients with atypical leg symptoms had a twofold risk of anxiety (OR = 1.9, 95% CI 1.1-3.5, p < 0.05). Adjusting for sex, age, ankle-brachial index, cardiovascular history, time since ankle-brachial index screening, clinical factors, and medication use, both pain at rest (OR = 3.4, 95% CI 1.6-7.0, p = 0.001) and atypical leg symptoms (OR = 2.3, 95% CI 1.1-4.9, p < 0.05) were associated with comorbid mood problems. In conclusion, PAD patients with atypical leg symptoms or pain at rest reported more impaired mood than patients without those symptoms. These patients should be monitored closely in clinical practice, as previous research in cardiovascular patients has shown that mood disorders and sub-threshold symptoms predict poor prognosis.

The inverse association between cardiorespiratory fitness and C-reactive protein is mediated by autonomic function: a possible role of the cholinergic antiinflammatory pathway

Although studies have shown an inverse association between cardiorespiratory fitness (CRF) and C-reactive protein (CRP) levels, the underlying mechanisms are not fully understood. There is emerging evidence that autonomic nervous system function is related to CRP levels. Because high CRF is related to improved autonomic function, we hypothesized that the association between high CRF and low CRP levels would be affected by autonomic nervous system function. Cross-sectional analyses were conducted on 2,456 asymptomatic men who participated in a medical screening program. Fasting blood samples for cardiovascular disease risk factors were analyzed, and CRF was measured by maximal exercise treadmill test with expired gas analysis. We used an index of cardiac autonomic imbalance defined as the ratio of resting heart rate to 1 min of heart rate recovery after exercise (RHR/HRR). CRF was significantly correlated with CRP (r = -0.16, P < 0.05), and RHR/HRR (r = -0.48, P < 0.05), while RHR/HRR was significantly correlated with CRP (r = 0.25, P < 0.05). In multivariable linear regression models that adjusted for age, body mass index, smoking, disease status, medications, lipid profiles, glucose, and systolic blood pressure, CRF was inversely associated with CRP (beta = -0.09, P < 0.05). However, this relationship was no longer significant after adjusting for RHR/HRR in a multivariable linear regression model (beta = -0.03, P = 0.29). These results suggest that autonomic nervous system function significantly affects the relationship between CRF and inflammation in middle-aged men. Thus, physical activity or exercise training may favorably affect the cholinergic antiinflammatory pathway, but additional research is needed to confirm this finding.

Metabolic syndrome and short-term heart rate variability in young adults. The cardiovascular risk in young Finns study

AIMS

Heart rate variability (HRV) can be used to estimate autonomic nervous control of the cardiovascular system. In middle-aged subjects, the metabolic syndrome (MetS) is associated with lower HRV. We hypothesized that alterations in autonomic balance are already present in young adults with the MetS, and analysed the association of short-term HRV with the MetS (using the National Cholesterol Education Program definition), in 1889 subjects aged 24-39 years.

METHODS

Short-term (3 min) HRV analysis included high-frequency (HF), low-frequency (LF) and total (TP) spectral components of HRV and LF/HF ratio.

RESULTS

The presence of the MetS was associated with lower HF, LF and TP in men and women, and with higher LF/HF ratio in women. In men, waist circumference was the strongest individual MetS component that associated with HRV. After adjustments for age and heart rate, MetS was associated with lower HF and higher LF/HF ratio in women, but only with a lower TP in men (all P < 0.05).

CONCLUSIONS

MetS is associated with lower HRV in young adults. The individual components of MetS are differentially associated with HRV in men and in women. Our results are consistent with lower vagal activity and a possible increase in sympathetic predominance in women with the MetS. This sex difference in vagal activity and sympathovagal balance may partly explain the greater increase in cardiovascular risk associated with MetS in women than in men.

The autonomic nervous system and ischemic stroke: a reciprocal interdependence

Signs and symptoms of autonomic nervous system (ANS) dysfunction are frequently reported after ischemic or haemorrhagic stroke and in many cases they exhibit peculiar patterns in relationship with the site and the extension of brain lesion. However if an ANS disorder can cause or predispose to a stroke is far from being correctly known. Evidences in favor of a pathogenetic mechanism of an ANS dysfunction are reported for myocardial infarction and such data are likely to be appropriate also for atherothrombotic type of ischemic stroke. On the other hand, it is well known that many risk factors for this pathology are strongly correlated with an altered functioning of ANS so that a reciprocal interdependence between ANS and stroke can be hypothesized. This review points to evidence the possible relationship existing between these two conditions and suggests a quite different diagnostic and therapeutic approach to both on the basis of their pathogenetic mechanisms.

Relationship between heart rate variability, interleukin-6, and soluble tissue factor in healthy subjects

Decreased heart rate variability (HRV) has been associated with an increased risk of atherosclerosis. We hypothesized that a decrease in frequency domains of resting HRV would be associated with elevated plasma levels of interleukin (IL)-6 and soluble tissue factor (sTF) both previously shown to prospectively predict atherothrombotic events in healthy subjects. Subjects were 102 healthy and unmedicated black and white middle-aged men and women. We determined IL-6 and sTF antigen in plasma and HRV measures from surface electrocardiogram data using spectral analysis. All statistical analyses controlled for age, gender, ethnicity, smoking status, blood pressure, and body mass index. Low amounts of low frequency (LF) power (beta=-0.31, p=0.007) and high frequency (HF) power (beta=-0.36, p=0.002) were associated with increased amounts of IL-6, explaining 7% and 9% of the variance, respectively. Interactions between LF power and IL-6 (p=0.002) and between HF power and IL-6 (p=0.012) explained 8% and 5%, respectively, of the variance in sTF. Post hoc analyses showed associations between IL-6 and sTF when LF power (beta=0.51, p<0.001) and HF power (beta=0.48, p<0.001) were low but not when LF power and high HF power were high. The findings suggest that systemic low-grade inflammatory activity is associated with a decrease in HRV. Furthermore, there was a positive relationship between plasma levels of IL-6 and sTF antigen when HRV was low. Inflammation and related hypercoagulability might particularly contribute to atherothrombotic events in a setting of decreased HRV.