scholarly journals BENEFICIAL EFFECTS OF MAGNETIC FIELDS ON THE HUMAN HEART A REVIEW OF CURRENT ADVANCES AND PROPOSED MECHANISMS

2018 ◽  
Vol 6 (11) ◽  
pp. 266-271
Author(s):  
Abraham A. Embi Bs
Keyword(s):  
Magnetic Fields ◽  
Vagus Nerve ◽  
Cardiac Arrhythmias ◽  
Cardiac Cells ◽  
Functional Improvement ◽  
Low Level ◽  
Beneficial Effects ◽  
Transcutaneous Stimulation ◽  
Prolonged Duration ◽  
Auricular Branch

The main purpose of this manuscript is to introduce the reader to the present “state of the art” in experimental Low Level Magnetic Fields nerve stimulation approaches to improve chaotic cardiac arrhythmias and muscle contractions. The area addressed in this paper is the transcutaneous application of Low Level Magnetic Fields to a branch of the vagus nerve. Cardiac Arrhythmias such as Atrial Fibrillation, as well as and muscle contractility were reversed by Low Level Transcutaneous Stimulation (LL-TS) of the Auricular Branch of the Vagus Nerve (ABVN). This treatment has been successfully reported in humans as well as in awaken and anesthetized animals such as rodents and dogs. The functional improvement has been attributed to a reversal of cardiac myocytes remodeling (reversal of fibrosis) resulting from experimentally provoking induced rapid heartbeats. The prolonged duration of a tachycardia state induces intracellular accumulation of glycogen leading into fibrosis, this in turn is hypothesized to impede the intercellular electrical communications of the specialized cardiac cells. It also reduces the functional ability of the main pumping chamber (Left Ventricle).

Abstract 11460: Chronic Intermittent Low Level Transcutaneous Electrical Stimulation of the Auricular Branch of the Vagus Nerve Improves Left Ventricular Remodeling in Conscious Dogs With Healed Myocardial Infarction

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Zhuo Wang ◽  
Lilei Yu ◽  
Songyun Wang ◽  
Bing Huang ◽  
Kai Liao ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Vagus Nerve ◽  
Ventricular Remodeling ◽  
Left Ventricular Remodeling ◽  
Left Ventricular ◽  
Conscious Dogs ◽  
Control Group ◽  
Low Level ◽  
Auricular Branch

Introduction: Vagus nerve stimulation (VNS) attenuates left ventricular remodeling after myocardial infarction (MI) by improving the imbalance of autonomic nervous system. Our previous study found Low-level tragus stimulation (LL-TS) had the same antiarrhythmic effects as VNS by regulation of the autonomic nervous system. Hypothesis: Chronic intermittent LL-TS could attenuate left ventricular remodeling in conscious dogs with healed myocardial infarction. Methods: Thirty beagle dogs were randomly divided into three groups. LL-TS group (n=10) and MI group (n=10) underwent left anterior descending coronary artery and all major diagonal branches ligation to introduce MI under general anesthesia. Control group (n=10) underwent sham surgery. Auricular vagus nerve stimulation (frequency 20Hz, pulse width 1ms) with duty cycle of 5s on and 5s off was delivered to the bilateral tragus in external auditory canal with ear-clips connected to a custom-made stimulator. The voltage slowing sinus rate was used as the threshold for setting LL-TS at 80% below that. The actual voltage of stimulation was in the range of 16 to 24V that did not cause any heart rate changes. LL-TS group was given four hours of LL-TS at 7-9AM and 4-6PM on conscious dogs from the day of MI introduction to the end of 90-day follow-up, MI group and control group were given no stimulations. Results: At the end of 90-days follow-up LL-TS group significantly reduced left ventricular dilatation, improve left ventricular contractile and diastolic function, reduced mean infarct size by about 50% compared with MI group. Also LL-TS treatment alleviated cardiac fibrosis around infarction border and significantly decreased protein level of collagen I, collagen III, TGF-β1, MMP-9 in noninfarcted left ventricular free wall tissue after MI. Moreover, the plasma level of hs-CRP, NE and NT-proBNP in LL-TS group was significantly lower than MI group from the 7th day to the end of follow-up. Conclusions: Chronic intermittent low-level transcutaneous electrical stimulation of the auricular branch of the vagus nerve can attenuate left ventricular remodeling and improve cardiac function in conscious dogs with healed myocardial infarction.

Abstract 11392: Chronic Low-Level Transcutaneous Electrical Stimulation of the Auricular Branch of the Vagus Nerve: A New Approach to Attenuate Neural Remodeling and Reduce Ventricular Arrhythmias in a Post-Infarction Canine Model

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Song y Wang ◽  
Li L Yu ◽  
Zhi B Lu ◽  
Zhuo Wang ◽  
Bing Huang ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Protein Expression ◽  
Vagus Nerve ◽  
Ventricular Arrhythmias ◽  
Transcutaneous Electrical Stimulation ◽  
Nerve Activity ◽  
Low Level ◽  
Ventricular Stimulation ◽  
Auricular Branch ◽  
Neural Remodeling

Introduction: Left stellate ganglion (LSG) and cardiac neural remodeling, which are associated with ventricular arrhythmias (VAs) in post-infarction model, can be attenuated by low-level vagus nerve stimulation. However, whether chronic low-level transcutaneous electrical stimulation at the tragus, where the auricular branch of vagus nerve innervate, can attenuate neural remodeling both in heart and LSG and then reduce VAs is unknown. Hypothesis: We hypothesized that chronic low-level tragus stimulation (LL-TS) would attenuate cardiac and LSG nerve remodeling and then reduce inducibility of VAs in a post-infarction model. Methods: Twenty beagles after ligating coronary artery were randomly divided into normal control (NC, n=4), MI treated with LL-TS (MI-TS n=8)and MI treated with shame LL-TS (MI-NTS, n=8)groups. LL-TS was performed at 80% below the threshold, at which sinus rate or atrioventricular conduction slowing can be initially induced, for 2 hours a day for 2 months. Left stellate ganglionic nerve activity (SGNA) and left thoracic vagal nerve activity (VNA) was recorded. Slope of ventricular restitution curves (Smax) and programmed ventricular stimulation were performed to evaluate VAs. Nerve sprouting, nerve synaptic density and associated protein expression both in LSG and hearts were evaluated by immunostaining or Western blotting. Results: Two months later, the increased SGNA induced by MI was attenuated by LL-TS. However, the increased VNA was strengthened.In the MI-TS group, the number of sympathetic nerves both in peri-infarct zone and LSG were reduced, while the parasympathetic nerve fibers were increased compared to MI-NTS group. Moreover, the expression of synaptophysin, NGF in peri-infarct as well as in LSG in the MI-TS group was significantly lower than the MI-NTS group, while the level of SK2 was much higher.Chronic LL-TS also significantly decreased the Smax, LF/HF ratio and arrhythmia score of programmed ventricular stimulation induced VAs. Conclusions: These findings suggested that chronic LL-TS augmented cardiac vagal and reduced sympathetic tone, attenuated cardiac and LSG nerve remodeling, regulated nerve associated protein expression and potentially contributed to reducing vulnerability to VAs.

scholarly journals Comparison of Repeated Doses of C-kit-Positive Cardiac Cells versus a Single Equivalent Combined Dose in a Murine Model of Chronic Ischemic Cardiomyopathy

2021 ◽  
Vol 22 (6) ◽  
pp. 3145
Author(s):  
Qianhong Li ◽  
Yiru Guo ◽  
Yibing Nong ◽  
Alex Tomlin ◽  
Anna Gumpert ◽  
...  
Keyword(s):  
Multiple Dose ◽  
Ischemic Cardiomyopathy ◽  
Dose Group ◽  
Weight Ratio ◽  
Cardiac Cells ◽  
Vehicle Group ◽  
Lv Function ◽  
Body Weight Ratio ◽  
Beneficial Effects ◽  
The Difference

Using a murine model of chronic ischemic cardiomyopathy caused by an old myocardial infarction (MI), we have previously found that three doses of 1 × 106 c-kit positive cardiac cells (CPCs) are more effective than a single dose of 1 × 106 cells. The goal of this study was to determine whether the beneficial effects of three doses of CPCs (1 × 106 cells each) can be fully replicated by a single combined dose of 3 × 106 CPCs. Mice underwent a 60-min coronary occlusion; after 90 days of reperfusion, they received three echo-guided intraventricular infusions at 5-week intervals: (1) vehicle × 3; (2) one combined dose of CPCs (3 × 106) and vehicle × 2; or (3) three doses of CPCs (1 × 106 each). In the combined-dose group, left ventricular ejection fraction (LVEF) improved after the 1st CPC infusion, but not after the 2nd and 3rd (vehicle) infusions. In contrast, in the multiple-dose group, LVEF increased after each CPC infusion; at the final echo, LVEF averaged 35.2 ± 0.6% (p < 0.001 vs. the vehicle group, 27.3 ± 0.2%). At the end of the study, the total cumulative change in EF from pretreatment values was numerically greater in the multiple-dose group (6.6 ± 0.6%) than in the combined-dose group (4.8 ± 0.8%), although the difference was not statistically significant (p = 0.08). Hemodynamic studies showed that several parameters of LV function in the multiple-dose group were numerically greater than in the combined-dose group (p = 0.08 for the difference in LVEF). Compared with vehicle, cardiomyocyte cross-sectional area was reduced only in the multiple-dose group (−32.7%, 182.6 ± 15.1 µm2 vs. 271.5 ± 27.2 µm2, p < 0.05, in the risk region and −28.5%, 148.5 ± 12.1 µm2 vs. 207.6 ± 20.5 µm2, p < 0.05, in the noninfarcted region). LV weight/body weight ratio and LV weight/tibia length ratios were significantly reduced in both cell treated groups vs. the vehicle group, indicating the attenuation of LV hypertrophy; however, the lung weight/body weight ratio was significantly reduced only in the multiple-dose group, suggesting decreased pulmonary congestion. Taken together, these results indicate that in mice with chronic ischemic cardiomyopathy, the beneficial effects of three doses of CPCs on LV function and hypertrophy cannot be fully replicated with a single dose, notwithstanding the fact that the total number of cells delivered with one or three doses is the same. Thus, it is the multiplicity of doses, and not the total number of cells, that accounts for the superiority of the repeated-dose paradigm. This study supports the idea that the efficacy of cell therapy in heart failure can be augmented by repeated administrations.

scholarly journals “Empowering” Cardiac Cells via Stem Cell Derived Mitochondrial Transplantation- Does Age Matter?

2021 ◽  
Vol 22 (4) ◽  
pp. 1824
Author(s):  
Matthias Mietsch ◽  
Rabea Hinkel
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Treatment Strategies ◽  
Cardiac Cells ◽  
Aging Effects ◽  
Beneficial Effects ◽  
Micro Rnas ◽  
New Treatment

With cardiovascular diseases affecting millions of patients, new treatment strategies are urgently needed. The use of stem cell based approaches has been investigated during the last decades and promising effects have been achieved. However, the beneficial effect of stem cells has been found to being partly due to paracrine functions by alterations of their microenvironment and so an interesting field of research, the “stem- less” approaches has emerged over the last years using or altering the microenvironment, for example, via deletion of senescent cells, application of micro RNAs or by modifying the cellular energy metabolism via targeting mitochondria. Using autologous muscle-derived mitochondria for transplantations into the affected tissues has resulted in promising reports of improvements of cardiac functions in vitro and in vivo. However, since the targeted treatment group represents mainly elderly or otherwise sick patients, it is unclear whether and to what extent autologous mitochondria would exert their beneficial effects in these cases. Stem cells might represent better sources for mitochondria and could enhance the effect of mitochondrial transplantations. Therefore in this review we aim to provide an overview on aging effects of stem cells and mitochondria which might be important for mitochondrial transplantation and to give an overview on the current state in this field together with considerations worthwhile for further investigations.

Effects of low-level 50 Hz magnetic fields on the level of host defense and on spleen colony formation

1999 ◽  
Vol 20 (1) ◽  
pp. 57-63 ◽  
Author(s):  
H.A. Korneva ◽  
V.A. Grigoriev ◽  
E.N. Isaeva ◽  
S.M. Kaloshina ◽  
F.S. Barnes
Keyword(s):  
Magnetic Fields ◽  
Host Defense ◽  
Colony Formation ◽  
Low Level

Recordings of cervical vagus nerve activity v1

2019 ◽  
Author(s):  
Vitaly Napadow ◽  
Ilknur Ay ◽  
Catherine Morello ◽  
Vitaly Napadow ◽  
Ilknur Ay ◽  
...  
Keyword(s):  
Vagus Nerve ◽  
Nerve Activity ◽  
Auricular Branch

The goal of this work is to evaluate laterality of vagus nerve efference evoked by unilateral auricular branch of the vagus nerve (ABVN) stimulation by performing bilateral recordings of cervical vagus nerve activity (CVNA).

scholarly journals Does non-invasive vagus nerve stimulation affect heart rate variability? A living and interactive Bayesian meta-analysis

2021 ◽  
Author(s):  
Vinzent Wolf ◽  
Anne Kühnel ◽  
Vanessa Teckentrup ◽  
Julian Koenig ◽  
Nils B. Kroemer
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Vagus Nerve ◽  
Brain Stimulation ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Meta Analysis ◽  
Current Evidence ◽  
Beneficial Effects ◽  
Non Invasive

AbstractNon-invasive brain stimulation techniques, such as transcutaneous auricular vagus nerve stimulation (taVNS), have considerable potential for clinical use. Beneficial effects of taVNS have been demonstrated on symptoms in patients with mental or neurological disorders as well as transdiagnostic dimensions, including mood and motivation. However, since taVNS research is still an emerging field, the underlying neurophysiological processes are not yet fully understood, and the replicability of findings on biomarkers of taVNS effects has been questioned. Here, we perform a living Bayesian random effects meta-analysis to synthesize the current evidence concerning the effects of taVNS on heart rate variability (HRV), a candidate biomarker that has, so far, received most attention in the field. To keep the synthesis of evidence transparent and up to date as new studies are being published, we developed a Shiny web app that regularly incorporates new results and enables users to modify study selection criteria to evaluate the robustness of the inference across potential confounds. Our analysis focuses on 17 single-blind studies comparing taVNS versus sham in healthy participants. These newly synthesized results provide strong evidence for the null hypothesis (g = 0.011, CIshortest = [−0.103, 0.125], BF01 = 25.587), indicating that acute taVNS does not alter HRV compared to sham. To conclude, based on a synthesis of the available evidence to date, there is no support for the hypothesis that HRV is a robust biomarker for acute taVNS. By increasing transparency and timeliness, we believe that the concept of living meta-analyses can lead to transformational benefits in emerging fields such as non-invasive brain stimulation.

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