Chronic vagus nerve stimulation attenuates vascular endothelial impairments and reduces the inflammatory profile via inhibition of the NF-κB signaling pathway in ovariectomized rats

Vagus nerve stimulation-induced stromal cell-derived factor-l alpha participates in angiogenesis and repair of infarcted hearts

AIMS

We aim to explore the role and mechanism of vagus nerve stimulation (VNS) in coronary endothelial cells and angiogenesis in infarcted hearts.

METHODS AND RESULTS

Seven days after rat myocardial infarction (MI) was prepared by ligation of the left anterior descending coronary artery, the left cervical vagus nerve was treated with electrical stimulation 1 h after intraperitoneal administration of the α7-nicotinic acetylcholine inhibitor mecamylamine or the mAChR inhibitor atropine or 3 days after local injection of Ad-shSDF-1α into the infarcted heart. Cardiac tissue acetylcholine (ACh) and serum ACh, tumour necrosis factor α (TNF-α), interleukin 1β (IL-1β) and interleukin 6 (IL-6) levels were detected by ELISA to determine whether VNS was successful. An inflammatory injury model in human coronary artery endothelial cells (HCAECs) was established by lipopolysaccharide and identified by evaluating TNF-α, IL-1β and IL-6 levels and tube formation. Immunohistochemistry staining was performed to evaluate CD31-positive vessel density and stromal cell-derived factor-l alpha (SDF-1α) expression in the MI heart in vivo and the expression and distribution of SDF-1α, C-X-C motif chemokine receptor 4 and CXCR7 in HCAECs in vitro. Western blotting was used to detect the levels of SDF-1α, V-akt murine thymoma viral oncogene homolog (AKT), phosphorylated AKT (pAKT), specificity protein 1 (Sp1) and phosphorylation of Sp1 in HCAECs. Left ventricular performance, including left ventricular systolic pressure, left ventricular end-diastolic pressure and rate of the rise and fall of ventricular pressure, should be evaluated 28 days after VNS treatment. VNS was successfully established for MI therapy with decreases in serum TNF-α, IL-1β and IL-6 levels and increases in cardiac tissue and serum ACh levels, leading to increased SDF-1α expression in coronary endothelial cells of MI hearts, triggering angiogenesis of MI hearts with increased CD31-positive vessel density, which was abolished by the m/nAChR inhibitors mecamylamine and atropine or knockdown of SDF-1α by shRNA. ACh promoted SDF-1α expression and its distribution along with the branch of the formed tube in HCAECs, resulting in an increase in the number of tubes formed in HCAECs. ACh increased the levels of pAKT and phosphorylation of Sp1 in HCAECs, resulting in inducing SDF-1α expression, and the specific effects could be abolished by mecamylamine, atropine, the PI3K/AKT blocker wortmannin or the Sp1 blocker mithramycin. Functionally, VNS improved left ventricular performance, which could be abolished by Ad-shSDF-1α.

CONCLUSIONS

VNS promoted angiogenesis to repair the infarcted heart by inducing SDF-1α expression and redistribution along new branches during angiogenesis, which was associated with the m/nAChR-AKT-Sp1 signalling pathway.

Vascular and autonomic function as early predictive biomarkers of the progression to gestational hypertension

Background

The changes in endothelial function, arterial stiffness, and heart rate variability (HRV) produced in the first trimester of pregnancy in women who develop gestational hypertension (GH) are still being investigated. Objective: to evaluate the HVR, endothelial function, and arterial stiffness changes during the first trimester of pregnancy and their relationship with the development of GH.

Methods

A group of women normotensive during the first trimester (n = 43), who later did (GH; n = 11) or did not (no-GH; n = 32) develop GH in that pregnancy, were enrolled. In the first trimester, endothelial function and arterial stiffness were evaluated through photoplethysmography. HRV, parasympathetic (PNS), and sympathetic (SNS) indexes were measured in a 5-minute continuous electrocardiogram record at rest sitting. The Griess reaction measured urinary nitrite excretion (NOx).

Results

Systolic blood pressure (SBP) values were higher in GH (no-GH: 105.8 ± 2.0 vs. GH: 112.7 ± 3.0 mmHg; p < 0.05). Endothelial function was decreased, and arterial stiffness was increased in GH. Only in GH the arterial stiffness was correlated with SBP (Pearson's r: 0.5594; 95%CI: 0.06106-0.8681; p < 0.05). In HRV, GH decreased low-frequency power and the ratio SD2/SD1. The inhibition of PNS was lower in GH. The NOx was reduced in GH (no-GH: 3.4 ± 0.4 vs. GH: 0.3 ± 0.1 μM/L; p < 0.001). NOx was correlated negatively with the SNS index only in GH.

Conclusions

Developed GH is preceded early in pregnancy by endothelial dysfunction and increased arterial stiffness. In this context, there are SNS-PNS interrelation modifications with less inhibition of PNS.

Exploring the potential of vagus nerve stimulation in treating brain diseases: a review of immunologic benefits and neuroprotective efficacy

The vagus nerve serves as a critical connection between the central nervous system and internal organs. Originally known for its effectiveness in treating refractory epilepsy, vagus nerve stimulation (VNS) has shown potential for managing other brain diseases, including ischaemic stroke, traumatic brain injury, Parkinson's disease, and Alzheimer's disease. However, the precise mechanisms of VNS and its benefits for brain diseases are not yet fully understood. Recent studies have found that VNS can inhibit inflammation, promote neuroprotection, help maintain the integrity of the blood-brain barrier, have multisystemic modulatory effects, and even transmit signals from the gut flora to the brain. In this article, we will review several essential studies that summarize the current theories of VNS and its immunomodulatory effects, as well as the therapeutic value of VNS for brain disorders. By doing so, we aim to provide a better understanding of how the neuroimmune network operates and inspire future research in this field.

The role of age-associated autonomic dysfunction in inflammation and endothelial dysfunction

Aging of the cardiovascular regulatory function manifests as an imbalance between the sympathetic and parasympathetic (vagal) components of the autonomic nervous system (ANS). The most characteristic change is sympathetic overdrive, which is manifested by an increase in the muscle sympathetic nerve activity (MSNA) burst frequency with age. Age-related changes that occur in vagal nerve activity is less clear. The resting tonic parasympathetic activity can be estimated noninvasively by measuring the increase in heart rate occurring in response to muscarinic cholinergic receptor blockade; animal study models have shown this to diminish with age. Humoral, cellular, and neural mechanisms work together to prevent non-resolving inflammation. This review focuses on the mechanisms underlying age-related alternations in the ANS and how an imbalance in the ANS, evaluated by MSNA and heart rate variability (HRV), potentially facilitates inflammation when the homeostatic mechanisms between reflex neural circuits and the immune system are compromised, particularly the dysfunction of the cholinergic anti-inflammatory reflex. Physiologically, the efferent arm of this reflex acts via the [Formula: see text] 7 nicotinic acetylcholine receptors expressed in macrophages, monocytes, dendritic cells, T cells, and endothelial cells to curb the release of inflammatory cytokines, in which inhibition of NF‑κB nuclear translocation and activation of a JAK/STAT-mediated signaling cascade in macrophages and other immune cells are implicated. This reflex is likely to become less adequate with advanced age. Consequently, a pro-inflammatory state induced by reduced vagus output with age is associated with endothelial dysfunction and may significantly contribute to the development and propagation of atherosclerosis, heart failure, and hypertension. The aim of this review is to summarize the relationship between ANS dysfunction, inflammation, and endothelial dysfunction in the context of aging. Meanwhile, this review also attempts to describe the role of HRV measures as a predictor of the level of inflammation and endothelial dysfunction in the aged population and explore the possible therapeutical effects of vagus nerve stimulation.

Lipidomic insights into the immune response and pearl formation in transplanted pearl oyster Pinctada fucata martensii

During pearl culture, the excess immune responses may induce nucleus rejection and death of pearl oysters after transplantation. To better understand the immune response and pearl formation, lipidomic analysis was applied to investigate changes in the serum lipid profile of pearl oyster Pinctada fucata martensii following transplantation. In total, 296 lipid species were identified by absolute quantitation. During wound healing, the content of TG and DG initially increased and then decreased after 3 days of transplantation with no significant differences, while the level of C22:6 decreased significantly on days 1 and 3. In the early stages of transplantation, sphingosine was upregulated, whereas PC and PUFAs were downregulated in transplanted pearl oyster. PI was upregulated during pearl sac development stages. GP and LC-PUFA levels were upregulated during pearl formation stage. In order to identify enriched metabolic pathways, pathway enrichment analysis was conducted. Five metabolic pathways were found significantly enriched, namely glycosylphosphatidylinositol-anchor biosynthesis, glycerophospholipid metabolism, alpha-linolenic acid metabolism, linoleic acid metabolism and arachidonic acid metabolism. Herein, results suggested that the lipids involved in immune response, pearl sac maturation, and pearl formation in the host pearl oyster after transplantation, which might lead to an improvement in the survival rate and pearl quality of transplanted pearl oyster.

Loss of α7nAChR enhances endothelial-to-mesenchymal transition after myocardial infarction via NF-κB activation

The myocardial fibrosis in response to myocardial infarction (MI) is closely related to the dysbalance of endothelial-to-mesenchymal transition (EndMT). Although numerous reports indicate that α7 nicotinic acetylcholine receptor (α7nAChR) activates the cholinergic anti-inflammatory pathway (CAP) to regulate the magnitude of inflammatory responses, the role of α7nAChR in myocardial fibrosis, as well as the underlying mechanisms, have not been elucidated. In this study, we evaluated cardiac function, fibrosis, and EndMT signaling using a mouse model of MI and interleukin (IL)-1β-induced human cardiac microvascular endothelial cells (HCMECs). In vivo, α7nAChR deletion increased cardiac dysfunction, exacerbated the cardiac inflammatory response, and NF-κB activation, and enhanced EndMT, as shown by higher expression levels of fibroblast markers (FSP-1, α-SMA, collagen I, Snail) and decreased levels of the FGFR1, glucocorticoid receptor (GR) and endothelial marker (CD31) compared to wild-type mice. In vitro, the pharmacological activation of α7nAChR with PNU282987 significantly inhibited IL-1β-induced EndMT, as shown by a reduced transition to the fibroblast-like phenotype and the expression of fibrotic markers. Moreover, the IL-1β-mediated activation of NF-κB pathway was suppressed by PNU282987. This anti-EndMT effect of α7nAChR was associated with regulation of Snail. Furthermore, Western blot analysis further revealed that the GR antagonist RU38486 could partially counteract the effect of PNU282987 on NF-κB expression. In conclusion, our results show that α7nAChR is involved in cardiac fibrosis by inhibiting EndMT, providing a novel approach to the treatment of MI.

Cervical Vagus Nerve Stimulation Improves Neurologic Outcome After Cardiac Arrest in Mice by Attenuating Oxidative Stress and Excessive Autophagy

BACKGROUND

Cerebral ischemia and reperfusion (I/R) induces oxidative stress and activates autophagy, leading to brain injury and neurologic deficits. Cervical vagus nerve stimulation (VNS) increases cerebral blood flow (CBF). In this study, we investigate the effect of VNS-induced CBF increase on neurologic outcomes after cardiac arrest (CA).

MATERIALS AND METHODS

A total of 40 male C57Bl/6 mice were subjected to ten minutes of asphyxia CA and randomized to vagus nerve isolation (VNI) or VNS treatment group. Eight mice received sham surgery and VNI. Immediately after resuscitation, 20 minutes of electrical stimulation (1 mA, 1 ms, and 10 Hz) was started in the VNS group. Electrocardiogram, blood pressure, and CBF were monitored. Neurologic and histologic outcomes were evaluated at 72 hours. Oxidative stress and autophagy were assessed at 3 hours and 24 hours after CA.

RESULTS

Baseline characteristics were not different among groups. VNS mice had better behavioral performance (ie, open field, rotarod, and neurologic score) and less neuronal death (p < 0.05, vs VNI) in the hippocampus. CBF was significantly increased in VNS-treated mice at 20 minutes after return of spontaneous circulation (ROSC) (p < 0.05). Furthermore, levels of 8-hydroxy-2'-deoxyguanosine in the blood and autophagy-related proteins (ie, LC-3Ⅱ/Ⅰ, Beclin-1, and p62) in the brain were significantly decreased in VNS mice. Aconitase activity was also reduced, and the p-mTOR/mTOR ratio was increased in VNS mice.

CONCLUSIONS

Oxidative stress induced by global brain I/R following CA/ROSC leads to early excessive autophagy and impaired autophagic flux. VNS promoted CBF recovery, ameliorating these changes. Neurologic and histologic outcomes were also improved.

Neurological manifestations and pathogenic mechanisms of COVID-19

Coronavirus disease (COVID-19) arising from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral infection has caused a worldwide pandemic, mainly owing to its highly virulent nature stemming from a very strong and highly efficacious binding to the angiotensin converting enzyme-2 (ACE2) receptor. As the pandemic developed, increasing numbers of COVID-19 patients with neurological manifestations were reported, strongly suggesting a causal relationship. Indeed, direct invasion of SARS-CoV-2 viral particles into the brain can occur through the cribriform plate via olfactory nerves, passage through a damaged blood-brain-barrier, or via haematogenic infiltration of infected leukocytes. Neurological complications range from potentially fatal encephalopathy and stroke, to the onset of headaches and dizziness, which despite their apparent innocuous presentation may still imply a more sinister pathology. Here, we summarize the most recent knowledge on the neurological presentations typically being associated with COVID-19, whilst providing potential pathophysiological mechanisms. The latter are centered upon hypoxic brain injury, generation of a cytokine storm with attendant immune-mediated damage, and a prothrombotic state. A better understanding of both the neuroinvasive properties of SARS-CoV-2 and the neurological complications of COVID-19 will be important to improve patient outcomes.

Changes in vascular function and autonomic balance during the first trimester of pregnancy and its relationship with the new-born weight

This study aimed to evaluate vascular function changes and autonomic balance during the first trimester of pregnancy and its relationship with the new-born weight. This prospective study performed in pregnant (PG) women and after delivery (not pregnant: NPG) evaluated the endothelial function (EF) and arterial stiffness (AS) by a non-invasive method. We evaluated the heart rate variability (HRV), parasympathetic nervous system (PNS), sympathetic nervous system (SNS) indexes by electrocardiogram (5 min) and the urinary nitrite excretion (NOx). PG increased EF and NOx and decreased AS and HRV. PG decreased the PNS index and augmented the SNS index. The new-born weight positively correlated with the PNS index (Pearson's r: 0.4291; p<.05), NOx, HRV and negatively correlated with AS. In summary, in pregnancy, although haemodynamically, the SNS activation plays a compensatory role, the low rates of PNS inhibition are essential to ensure normal foetal growth.Impact StatementWhat is already known on this subject? In pregnancy, there are adaptive physiological changes in the cardiovascular system that include increases of EF and decreases AS with an SNS activation. The study of HRV lets to predict the SNS and PNS balance and how they affect blood pressure and vascular function.What the results of this study add? Although it is known that SNS activation plays a compensatory role in healthy pregnancy, this study adds the critical role of PNS. Early in pregnancy, the low rates of PNS inhibition are essential to ensure normal foetal growth.What the implications are of these findings for clinical practice and/or further research? The present results show a potential predictive value of SNS and PNS activity early in pregnancy. It will provide valuable information not only on the pregnant woman's vascular function but also on the new-born weight.

Vagus nerve stimulation optimized cardiomyocyte phenotype, sarcomere organization and energy metabolism in infarcted heart through FoxO3A-VEGF signaling

Vagus nerve stimulation (VNS) restores autonomic balance, suppresses inflammation action and minimizes cardiomyocyte injury. However, little knowledge is known about the VNS’ role in cardiomyocyte phenotype, sarcomere organization, and energy metabolism of infarcted hearts. VNS in vivo and acetylcholine (ACh) in vitro optimized the levels of α/β-MHC and α-Actinin positive sarcomere organization in cardiomyocytes while reducing F-actin assembly of cardiomyocytes. Consistently, ACh improved glucose uptake while decreasing lipid deposition in myocytes, correlating both with the increase of Glut4 and CPT1α and the decrease of PDK4 in infarcted hearts in vivo and myocytes in vitro, attributing to improvement in both glycolysis by VEGF-A and lipid uptake by VEGF-B in response to Ach. This led to increased ATP levels accompanied by the repaired mitochondrial function and the decreased oxygen consumption. Functionally, VNS improved the left ventricular performance. In contrast, ACh-m/nAChR inhibitor or knockdown of VEGF-A/B by shRNA powerfully abrogated these effects mediated by VNS. On mechanism, ACh decreased the levels of nuclear translocation of FoxO3A in myocytes due to phosphorylation of FoxO3A by activating AKT. FoxO3A overexpression or knockdown could reverse the specific effects of ACh on the expression of VEGF-A/B, α/β-MHC, Glut4, and CPT1α, sarcomere organization, glucose uptake and ATP production. Taken together, VNS optimized cardiomyocytes sarcomere organization and energy metabolism to improve heart function of the infarcted heart during the process of delaying and/or blocking the switch from compensated hypertrophy to decompensated heart failure, which were associated with activation of both P13K/AKT-FoxO3A-VEGF-A/B signaling cascade.

SARS-CoV-2 Dissemination Through Peripheral Nerves Explains Multiple Organ Injury

Coronavirus disease (CoVID-19), caused by recently identified severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2), is characterized by inconsistent clinical presentations. While many infected individuals remain asymptomatic or show mild respiratory symptoms, others develop severe pneumonia or even respiratory distress syndrome. SARS-CoV-2 is reported to be able to infect the lungs, the intestines, blood vessels, the bile ducts, the conjunctiva, macrophages, T lymphocytes, the heart, liver, kidneys, and brain. More than a third of cases displayed neurological involvement, and many severely ill patients developed multiple organ infection and injury. However, less than 1% of patients had a detectable level of SARS-CoV-2 in the blood, raising a question of how the virus spreads throughout the body. We propose that nerve terminals in the orofacial mucosa, eyes, and olfactory neuroepithelium act as entry points for the brain invasion, allowing SARS-CoV-2 to infect the brainstem. By exploiting the subcellular membrane compartments of infected cells, a feature common to all coronaviruses, SARS-CoV-2 is capable to disseminate from the brain to periphery via vesicular axonal transport and passive diffusion through axonal endoplasmic reticula, causing multiple organ injury independently of an underlying respiratory infection. The proposed model clarifies a wide range of clinically observed phenomena in CoVID-19 patients, such as neurological symptoms unassociated with lung pathology, protracted presence of the virus in samples obtained from recovered patients, exaggerated immune response, and multiple organ failure in severe cases with variable course and dynamics of the disease. We believe that this model can provide novel insights into CoVID-19 and its long-term sequelae, and establish a framework for further research.

Harnessing the Inflammatory Reflex for the Treatment of Inflammation-Mediated Diseases

Treating diseases nonpharmacologically, using targeted neurostimulation instead of systemic drugs, is a hallmark of the burgeoning field of bioelectronic medicine. In this review, we provide a brief overview of the discovery and function of the prototypical neuroimmune reflex, the "inflammatory reflex." We discuss various biomarkers developed and used to translate early physiological discoveries into dosing parameters used in experimental settings, from the treatment of animal models of disease through a proof-of-concept clinical study in rheumatoid arthritis (RA). Finally, we relate how unique aspects of this form of therapy enabled the design of a next-generation implanted pulse generator using integrated electrodes, currently under evaluation in a U.S.-based clinical study for patients with drug refractory RA.

Are Oxidative Stress and Inflammation Mediators of Bone Loss Due to Estrogen Deficiency? A Review of Current Evidence

Osteoporosis is one of the major health issues associated with menopause-related estrogen deficiency. Various reports suggest that the hormonal changes related to menopausal transition may lead to the derangement of redox homeostasis and ultimately oxidative stress. Estrogen deficiency and oxidative stress may enhance the expression of genes involved in inflammation. All these factors may contribute, in synergy, to the development of postmenopausal osteoporosis. Previous studies suggest that estrogen may act as an antioxidant to protect the bone against oxidative stress, and as an antiinflammatory agent in suppressing pro-inflammatory and pro-osteoclastic cytokines. Thus, the focus of the current review is to examine the relationship between estrogen deficiency, oxidative stress and inflammation, and the impacts of these phenomena on skeletal health in postmenopausal women.

Closed-Loop Implantable Therapeutic Neuromodulation Systems Based on Neurochemical Monitoring

Closed-loop or intelligent neuromodulation allows adjustable, personalized neuromodulation which usually incorporates the recording of a biomarker, followed by implementation of an algorithm which decides the timing (when?) and strength (how much?) of stimulation. Closed-loop neuromodulation has been shown to have greater benefits compared to open-loop neuromodulation, particularly for therapeutic applications such as pharmacoresistant epilepsy, movement disorders and potentially for psychological disorders such as depression or drug addiction. However, an important aspect of the technique is selection of an appropriate, preferably neural biomarker. Neurochemical sensing can provide high resolution biomarker monitoring for various neurological disorders as well as offer deeper insight into neurological mechanisms. The chemicals of interest being measured, could be ions such as potassium (K⁺), sodium (Na⁺), calcium (Ca²⁺), chloride (Cl⁻), hydrogen (H⁺) or neurotransmitters such as dopamine, serotonin and glutamate. This review focusses on the different building blocks necessary for a neurochemical, closed-loop neuromodulation system including biomarkers, sensors and data processing algorithms. Furthermore, it also highlights the merits and drawbacks of using this biomarker modality.

A rodent model for long-term vagus nerve stimulation experiments

Aim: Investigations into the benefits of vagus nerve stimulation (VNS) using rodents have led to promising findings for treating clinical disorders. However, the majority of research has been limited to acute timelines. We developed a rodent model for longitudinal assessment of VNS and validated it with a long-term experiment incorporating continuous physiological monitoring. While the primary aim was not to investigate the effects of VNS on the cardiovascular system, we analyzed cardiovascular parameters to demonstrate the model's capabilities in a long-term stimulation-and-recording setup. Materials & methods: Rats were implanted with a cuff electrode around the cervical vagus nerve and electrocardiogram monitoring devices were implanted in the peritoneal cavity. We also designed a connector mount for seamless access to the cuff electrode for VNS in awake-behaving rats. Results & conclusion: Results signified easy-to-interface VNS system, electrode robustness and discernible physiological signals in a long-term setup. Analysis of the cardiovascular parameters revealed some transient effects during VNS. Our proposed model enables long-term VNS experiments along with physiological monitoring in unanesthetized rats.

Vagus Nerve Stimulation Attenuates Acute Skeletal Muscle Injury Induced by Ischemia-Reperfusion in Rats

Vagus nerve stimulation (VNS) has been shown to attenuate ischemia-reperfusion (I/R) injury in multiple organs. The present study aimed at investigating whether VNS could exert protective effects against I/R injury in the skeletal muscle. Male Sprague-Dawley rats were randomly divided into 3 groups: the control, I/R, and I/R+VNS groups. The skeletal muscle I/R (SMI/R) model was induced by occlusion of the left femoral artery for 2.5 hours followed by reperfusion for 2 hours. The vagal nerve trunk was separated, and VNS was performed during the whole I/R process. The intensity of VNS was optimized in each rat to obtain a 10% reduction in the heart rate relative to the value before stimulation. After the experiment, the blood sample and left gastrocnemius muscle tissues were collected for histological examination, biochemical analysis, and molecular biological detection. During the I/R process, VNS significantly reduced cellular apoptosis, necrosis, and inflammatory cell infiltration compared to sham VNS. The VNS treatment also decreased the inflammatory response, alleviated oxidative stress, and improved vascular endothelial function (p < 0.05 for each). In contrast, the I/R group showed an opposite effect compared to the control group. The present study indicated that VNS could protect against SMI/R injury by suppressing excessive inflammation, alleviating oxidative stress, and preserving vascular endothelial function.

Vagal Nerve Stimulation Attenuates Ischemia-Reperfusion Induced Retina Dysfunction in Acute Ocular Hypertension

Purpose: The present study aimed to investigate whether cervical vagal nerve stimulation (VNS) could prevent retinal ganglion cell (RGC) loss and retinal dysfunction after ischemia/reperfusion (I/R) injury.

Methods: First, rats were randomly divided into sham group (n = 4) and VNS group (n = 12). Activation of the nodose ganglia (NOG), nucleus of the solitary tract (NTS), superior salivatory nucleus (SSN), and pterygopalatine ganglion (PPG) neural circuit were evaluated by c-fos expression at 0 h after sham VNS and at 0 h (n = 4), 6 h (n = 4), 72 h (n = 4) after VNS. Secondly, rats were randomly assigned to I/R group (pressure-induced retinal ischemia for 1 h and reperfusion for 1 h in the right eye, n = 16) and I/R+VNS group (right cervical VNS for 2 h during the I/R period, n = 16). The left eye of each rat served as a control. Electroretinogram (ERG), RGC numbers, tumor necrosis factor-α (TNF-α) and vasoactive intestinal polypeptide (VIP) levels in retina were determined. Additionally, the level of VIP in PPG was evaluated.

Results: In the first part of the study, compared with the sham group, the VNS group exhibited significantly increased expression of c-fos in NOG, NTS, SSN, and PPG tissues at 0, 6, and 72 h. In the second part of the study, compared with left eyes, retinal function in right eyes (as assessed by the a-wave, b-wave and the oscillatory potential amplitudes of ERG and RGC data) was significantly decreased by I/R. The decreased retinal function was attenuated by VNS. In addition, I/R induced an increase in inflammation, which was reflected by elevated TNF-α expression in the retina. VNS significantly attenuated the increase in I/R-induced inflammation. Moreover, VIP expression in the retina and PPG, which may contribute to the inhibition of the inflammatory response, was significantly increased after VNS.

Conclusion: VNS could protect against retinal I/R injury by downregulating TNF-α. Upregulation of VIP expression due to activation of the NOG-NTS-SSN-PPG neural circuit may underlie to the protective effects of VNS.

Vesicular acetylcholine transport deficiency potentiates some inflammatory responses induced by diesel exhaust particles

Endogenous acetylcholine (ACh), which depends of the levels of vesicular ACh transport (VAChT) to be released, is the central mediator of the cholinergic anti-inflammatory system. ACh controls the release of cytokine in different models of inflammation. Diesel exhaust particles (DEP) are one of the major environmental pollutants produced in large quantity by automotive engines in urban center. DEP bind the lung parenchyma and induce inflammation. We evaluated whether cholinergic dysfunction worsens DEP-induced lung inflammation. Male mice with decreased ACh release due to reduced expression of VAChT (VAChT-KD mice) were submitted to DEP exposure for 30 days (3 mg/mL of DEP, once a day, five days a week) or saline. Pulmonary function and inflammation as well as extracellular matrix fiber deposition were evaluated. Additionally, airway and nasal epithelial mucus production were quantified. We found that DEP instillation worsened lung function and increased lung inflammation. Higher levels of mononuclear cells were observed in the peripheral blood of both wild-type (WT) and VAChT-KD mice. Also, both wild-type (WT) and VAChT-KD mice showed an increase in macrophages in bronchoalveolar lavage fluid (BALF) as well as increased expression of IL-4, IL-6, IL-13, TNF-α, and NF-κB in lung cells. The collagen fiber content in alveolar septa was also increased in both genotypes. On the other hand, we observed that granulocytes were increased only in VAChT-KD peripheral blood. Likewise, increased BALF lymphocytes and neutrophils as well as increased elastic fibers in alveolar septa, airway neutral mucus, and nasal epithelia acid mucus were observed only in VAChT-KD mice. The cytokines IL-4 and TNF-α were also higher in VAChT-KD mice compared with WT mice. In conclusion, decreased ability to release ACh exacerbates some of the lung alterations induced by DEP in mice, suggesting that VAChT-KD animals are more vulnerable to the effects of DEP in the lung.

Electro-acupuncture regulates the cholinergic anti-inflammatory pathway in a rat model of chronic obstructive pulmonary disease

OBJECTIVE

Acupuncture has a definite therapeutic effect on chronic obstructive pulmonary disease (COPD), and the cholinergic anti-inflammatory pathway (CAP) has been shown to be involved in regulation of inflammation. In this study, we investigated whether electro-acupuncture (EA) affects the CAP in COPD.

METHODS

Sprague-Dawley rats were induced into COPD through exposure to cigarette smoke combined with lipopolysaccharide. EA treatment was applied at Zusanli (ST36) and Feishu (BL13) points for 30 min/d for 7 d. Seventy-two rats were randomly divided into six study groups, including normal, normal + EA, normal + α-bungarotoxin (α-BGT) (the antagonist of the nicotinic acetylcholine receptor α7 subunit (α7nAChR)) + EA, COPD, COPD + EA, and COPD + α-BGT + EA. Lung function, pathology and vagus nerve discharge were tested. The levels of acetylcholine (ACh), acetylcholinesterase (AChE), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in bronchoalveolar lavage fluid (BALF) and lung tissue were measured by enzyme-linked immunosorbent assay. The mRNA and protein expression and immunoreactivity of α7nAChR and its postreceptor inflammation signal pathway, including janus kinase 2 (JAK2), signal transducers and activators of transcription 3 (STAT3), nuclear factor-κB (NF-κB), were observed by quantitative reverse transcription-polymerase chain reaction, Western blot and immunohistochemistry.

RESULTS

Compared with normal rats, there were a significant decline in lung function and discharge of the vagus nerve (P < 0.01), a marked sign of lung inflammation and an increase of ACh, AChE, IL-6 and TNF-α level in BALF or lung tissue (P < 0.05, P < 0.01) and higher expression of α7nAChR, JAK2, STAT3 and NF-κB (P < 0.05, P < 0.01) in the COPD rats. In rats receiving EA, the lung function and vagal discharge were enhanced (P < 0.01), lung inflammation was improved and the levels of ACh, AChE, IL-6 and TNF-α were decreased (P < 0.01). Further, the expression of α7nAChR, JAK2, STAT3 and NF-κB was downregulated (P < 0.05, P < 0.01). However, the above effects of EA were blocked in rats injected with α-BGT (P < 0.01).

CONCLUSION

EA treatment can reduce the lung inflammatory response and improve lung function in COPD, which may be related to its involvement in the regulation of CAP.

Sex-Specific Contributions of Endothelin to Hypertension

PURPOSE OF REVIEW

Men and women differ in the prevalence, pathophysiology and control rate of hypertension in an age-dependent manner. The renal endothelin system plays a central role in sex differences in blood pressure regulation by control of sodium excretion and vascular function. Improving our understanding of the sex differences in the endothelin system, especially in regard to blood pressure regulation and sodium homeostasis, will fill a significant gap in our knowledge and may identify sex-specific therapeutic targets for management of hypertension.

RECENT FINDINGS

The current review will highlight evidence for the potential role for endothelin system in the pathophysiology of hypertension within three female populations: (i) postmenopausal women, (ii) women suffering from preeclampsia, or (iii) pulmonary arterial hypertension. Clinical trials that specifically address cardiovascular and renal diseases in females under different hormonal status are limited. Studies of the modulatory role of gonadal hormones and sex-specific mechanisms on critically important systems involved, such as endothelin, are needed to establish new clinical practice guidelines based on systematic evidence.

Cholinergic Stimulation Improves Oxidative Stress and Inflammation in Experimental Myocardial Infarction

We previously reported that cholinergic stimulation with pyridostigmine (PY) induces anti-inflammatory cell recruitment soon after myocardial infarction (MI). In this study, we evaluated the anti-inflammatory effects of PY during the proliferative phase of cardiac repair by analyzing the infiltration of macrophages, Treg lymphocytes, oxidative stress and inflammatory cytokines. Wistar rats underwent control sham surgery or ligation of the left coronary artery and were randomly allocated to remain untreated (untreated infarcted group, I) or to receive PY (30 mg·kg(−1)·day(−1)) in the supplied water (infarcted treated group, I + PY). Blood pressure and heart rate variability were registered at day 5 post-MI. The animals were euthanized 7 days after thoracotomy, when the hearts were removed and processed for immunohistochemistry (CD68, CD206, FOXP3), cytokines (IL-1β, IL-6, IL-10, TNF-α) and oxidative stress (superoxide dismutase, catalase, glutathione peroxidase, lipidic and protein peroxidation). PY treatment increased parasympathetic modulation, M2 macrophages and the anti-oxidant enzyme activity but reduced protein oxidation (carbonyls) and the concentration of IL-1β, IL-6, TNF-α and IL-10. Cholinergic stimulation induces parasympathetic neuro-immune modulation and anti-inflammatory cell enrollment as well as prevents oxidative stress and cytokine production after MI.

Screening bioactive quality control markers of QiShenYiQi dripping pills based on the relationship between the ultra-high performance liquid chromatography fingerprint and vascular protective activity

Traditional Chinese medicine consists of complex phytochemical constituents. Selecting appropriate analytical markers of traditional Chinese medicine is a critical step in quality control. Currently, the combination of fingerprinting and efficacy evaluation is considered as a useful method for screening active ingredients in complex mixtures. This study was designed to develop an orthogonal partial least squares model for screening bioactive quality control markers of QishenYiqi dripping pills based on the fingerprint-efficacy relationship. First, the chemical fingerprints of 49 batches of QishenYiqi dripping pill samples were established by ultra-high performance liquid chromatography coupled with a photodiode array detector. Second, ultra-high performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry was exploited to systematically investigate the 36 copossessing fingerprint components in QishenYiqi dripping pills. The vascular protective activity of QishenYiqi dripping pills was determined by using a cell counting kit-8 assay. Finally, fingerprint-efficacy relationship was established by orthogonal partial least squares model. The results indicated that ten components exhibited strong correlation with vascular protective activity, and these were preliminarily screened as quality control markers. The present study provided a novel idea for the study of the pharmacodynamic material basis and quality evaluation of QishenYiqi dripping pills.

Vagus nerve stimulation: state of the art of stimulation and recording strategies to address autonomic function neuromodulation

OBJECTIVE

Neural signals along the vagus nerve (VN) drive many somatic and autonomic functions. The clinical interest of VN stimulation (VNS) is thus potentially huge and has already been demonstrated in epilepsy. However, side effects are often elicited, in addition to the targeted neuromodulation.

APPROACH

This review examines the state of the art of VNS applied to two emerging modulations of autonomic function: heart failure and obesity, especially morbid obesity.

MAIN RESULTS

We report that VNS may benefit from improved stimulation delivery using very advanced technologies. However, most of the results from fundamental animal studies still need to be demonstrated in humans.