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https://www.readbyqxmd.com/read/28925529/cerebrovascular-response-to-the-cold-pressor-test-the-critical-role-of-carbon-dioxide
#1
Michael M Tymko, Thijs P Kerstens, Kevin W Wildfong, Philip N Ainslie
In addition to increasing sympathetic nervous activity, blood pressure, and cerebral blood flow (CBF), the cold pressor test (CPT) stimulates pain receptors, which may increase ventilation above metabolic demand; this response likely reduces the partial pressure of end-tidal carbon dioxide (PET CO2 ), and will attenuate elevations in CBF. We hypothesized: (1) CPT would elicit hyperventilation, effectively lowering PET CO2 ; (2) the CBF response will be elevated during an isocapnic (controlled PET CO2 ), compared to a poikilocapnic CPT (uncontrolled PET CO2 ); (3) In response to CPT, the common carotid artery (CCA) will vasodilatate, while the internal carotid artery (ICA) will remain unchanged to help regulate CBF...
September 19, 2017: Experimental Physiology
https://www.readbyqxmd.com/read/28923792/p2y2-nucleotide-receptor-prompts-human-cardiac-progenitor-cell-activation-by-modulating-hippo-signaling
#2
Farid G Khalafalla, Steven R Greene, Hashim Khan, Kelli Ilves, Megan M Monsanto, Roberto Alvarez, Monica Chavarria, Jonathan H Nguyen, Benjamin Norman, Walter P Dembitsky, Mark A Sussman
Rationale: Autologous stem cell therapy using human c-Kit(+) cardiac progenitor cells (hCPCs) is a promising therapeutic approach for treatment of heart failure (HF). However, hCPCs derived from aged HF patients with genetic predispositions and/or comorbidities of chronic diseases exhibit poor proliferative and migratory capabilities, which impairs overall reparative potential for injured myocardium. Therefore, empowering functionally compromised hCPCs with pro-regenerative molecules ex vivo is crucial for improving the therapeutic outcome in HF patients...
September 18, 2017: Circulation Research
https://www.readbyqxmd.com/read/28923351/functionally-redundant-control-of-cardiac-hypertrophic-signaling-by-inositol-1-4-5-trisphosphate-receptors
#3
M Iveth Garcia, Anja Karlstaedt, Jessica J Chen, Javier Amione-Guerra, Keith A Youker, Heinrich Taegtmeyer, Darren Boehning
Calcium plays an integral role to many cellular processes including contraction, energy metabolism, gene expression, and cell death. The inositol 1, 4, 5-trisphosphate receptor (IP3R) is a calcium channel expressed in cardiac tissue. There are three IP3R isoforms encoded by separate genes. In the heart, the IP3R-2 isoform is reported to being most predominant with regards to expression levels and functional significance. The functional roles of IP3R-1 and IP3R-3 in the heart are essentially unexplored despite measureable expression levels...
September 15, 2017: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/28923249/akap-lbc-mediates-protection-against-doxorubicin-induced-cardiomyocyte-toxicity
#4
Stefania Caso, Darko Maric, Miroslav Arambasic, Susanna Cotecchia, Dario Diviani
Doxorubicin (DOX) is a chemotherapic agent that is widely used to treat hematological and solid tumors. Despite its efficacy, DOX displays significant cardiac toxicity associated with cardiomyocytes death and heart failure. Cardiac toxicity is mainly associated with the ability of DOX to alter mitochondrial function. The current lack of treatments to efficiently prevent DOX cardiotoxicity underscores the need of new therapeutic approaches. Our current findings show that stimulation of cardiomyocytes with the α1-adrenergic receptor (AR) agonist phenylephrine (PE) significantly inhibits the apoptotic effect of DOX...
September 16, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28922986/attenuation-of-doxorubicin-induced-cardiotoxicity-and-genotoxicity-by-an-indole-based-natural-compound-3-3-diindolylmethane-dim-through-activation-of-nrf2-are-signaling-pathways-and-inhibiting-apoptosis
#5
Subhadip Hajra, Abhishek Basu, Somnath Singha Roy, Arup Ranjan Patra, Sudin Bhattacharya
The most crucial complication related to doxorubicin (DOX) therapy is nonspecific cytotoxic effect on healthy normal cells. The clinical use of this broad-spectrum chemotherapeutic agent is restricted due to development of severe form of cardiotoxicity, myelosuppression and genotoxicity which interfere with therapeutic schedule, compromise treatment outcome and may lead to secondary malignancy. 3,3'-diindolylmethane (DIM) is a naturally occurring plant alkaloid formed by the hydrolysis of indolylmethyl glucosinolate (glucobrassicin)...
September 18, 2017: Free Radical Research
https://www.readbyqxmd.com/read/28920705/human-endothelial-progenitor-cell-derived-exosomes-increase-proliferation-and-angiogenesis-in-cardiac-fibroblasts-by-promoting-the-mesenchymal-endothelial-transition-and-reducing-high-mobility-group-box-1-protein-b1-expression
#6
Xiao Ke, Dahao Yang, Jiawen Liang, Xing Wang, Shaoyun Wu, Xiaoqing Wang, Chengheng Hu
Myocardial fibrosis is a characteristic feature of cardiomyopathies. However, no effective strategies to attenuate cardiac fibrosis are currently available. Late-stage endothelial progenitor cells (EPCs) are precursors of endothelial cells (ECs) that repair the heart through a paracrine mechanism. In the present study, we tested whether EPC-derived exosomes regulate the differentiation of fibroblasts into ECs. We isolated late-stage EPCs from human peripheral blood (PB) and used immunofluorescence and flow cytometry to confirm their identity...
September 18, 2017: DNA and Cell Biology
https://www.readbyqxmd.com/read/28919864/%C3%AE-subunits-control-the-effects-of-human-kv4-3-potassium-channel-phosphorylation
#7
Geoffrey W Abbott
The transient outward K(+) current, Ito, activates early in the cardiac myocyte action potential, to begin repolarization. Human Ito is generated primarily by two Kv4.3 potassium channel α subunit splice variants (Kv4.3L and Kv4.3S) that diverge only by a C-terminal, membrane-proximal, 19-residue stretch unique to Kv4.3L. Protein kinase C (PKC) phosphorylation of threonine 504 within the Kv4.3L-specific 19-residues mediates α-adrenergic inhibition of Ito in human heart. Kv4.3 is regulated in human heart by various β subunits, including cytosolic KChIP2b and transmembrane KCNEs, yet their impact on the functional effects of human Kv4...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28919378/sudden-death-mechanisms-in-non-ischemic-cardiomyopathies-insights-gleaned-from-clinical-implantable-cardioverter-defibrillator-trials
#8
Benjamin A Steinberg, Siva K Mulpuru, James C Fang, Bernard J Gersh
Sudden cardiac death (SCD) represents a major cause of death among patients with heart failure. While scar-based, macro-reentrant ventricular tachycardia and ventricular fibrillation (VT/VF) is the primary etiology for SCD among patients with ischemic cardiomyopathy, a more diverse set of mechanisms and substrates are likely at play for the diverse group of patients characterized by non-ischemic, dilated cardiomyopathy (NICM). These causes may include scar-based re-entry, but also neurohormonal stimulation (sympathetic, parasympathetic, renin-angiotensin-aldosterone), inflammation, and non-arrhythmic processes occurring in the context of a genetic predisposition...
September 14, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28919363/thoracic-spinal-cord-and-cervical-vagosympathetic-neuromodulation-obtund-nodose-sensory-transduction-of-myocardial-ischemia
#9
Siamak Salavatian, Eric Beaumont, David Gibbons, Matthew Hammer, Donald B Hoover, J Andrew Armour, Jeffrey L Ardell
BACKGROUND: Autonomic regulation therapy involving either vagus nerve stimulation (VNS) or spinal cord stimulation (SCS) represents emerging bioelectronic therapies for heart disease. The objective of this study was to determine if VNS and/or SCS modulate primary cardiac afferent sensory transduction of the ischemic myocardium. METHODS: Using extracellular recordings in 19 anesthetized canines, of 88 neurons evaluated, 36 ventricular-related nodose ganglia sensory neurons were identified by their functional activity responses to epicardial touch, chemical activation of their sensory neurites (epicardial veratridine) and great vessel (descending aorta or inferior vena cava) occlusion...
August 18, 2017: Autonomic Neuroscience: Basic & Clinical
https://www.readbyqxmd.com/read/28919131/optogenetic-targeting-of-cardiac-myocytes-and-non-myocytes-tools-challenges-and-utility
#10
Callum M Johnston, Eva A Rog-Zielinska, Eike M Wülfers, Torsten Houwaart, Urszula Siedlecka, Thomas Knöpfel, Peter Kohl, Franziska Schneider-Warme
In optogenetics, light-activated proteins are used to monitor and modulate cellular behaviour with light. Combining genetic targeting of distinct cellular populations with defined patterns of optical stimulation enables one to study specific cell classes in complex biological tissues. In the current study we attempted to investigate the functional relevance of heterocellular electrotonic coupling in cardiac tissue in situ. In order to do that, we used a Cre-Lox approach to express the light-gated cation channel Channelrhodopsin-2 (ChR2) specifically in either cardiac myocytes or non-myocytes...
September 15, 2017: Progress in Biophysics and Molecular Biology
https://www.readbyqxmd.com/read/28914970/microrna-410-is-involved-in-mitophagy-after-cardiac-ischemia-reperfusion-injury-by-targeting-high-mobility-group-box-1-protein
#11
Fan Yang, Tong Li, Zhihuan Dong, Rui Mi
Mitochondrial dysfunction has emerged as a critical pathophysiological factor of myocardial ischemia/reperfusion (I/R) injury. A thorough understanding of mitochondrial dysfunction during I/R at the molecular level is urgently needed. One prominent microRNA, miR-410, was previously reported to be dynamically regulated in diverse cardiomyopathies, but its mechanism is unclear. In the present study, in a cardiac I/R injury mice model, the expression of miR-410 was significantly upregulated, accompanied with decreased mitochondrial function and mitophagy deficit...
September 15, 2017: Journal of Cellular Biochemistry
https://www.readbyqxmd.com/read/28913625/calcium-release-dependent-inactivation-precedes-formation-of-the-tubular-system-in-developing-rat-cardiac-myocytes
#12
Katarina Macková, Alexandra Zahradníková, Matej Hoťka, Barbora Hoffmannová, Ivan Zahradník, Alexandra Zahradníková
Developing cardiac myocytes undergo substantial structural and functional changes transforming the mechanism of excitation-contraction coupling from the embryonic form, based on calcium influx through sarcolemmal DHPR calcium channels, to the adult form, relying on local calcium release through RYR calcium channels of sarcoplasmic reticulum stimulated by calcium influx. We characterized day-by-day the postnatal development of the structure of sarcolemma, using techniques of confocal fluorescence microscopy, and the development of the calcium current, measured by the whole-cell patch-clamp in isolated rat ventricular myocytes...
September 14, 2017: European Biophysics Journal: EBJ
https://www.readbyqxmd.com/read/28912359/left-ventricular-strain-rate-is-reduced-during-voluntary-apnea-in-healthy-humans
#13
Joshua R Smith, Shelbi L Sutterfield, Dryden R Baumfalk, Kaylin D Didier, Shane M Hammer, Jacob Troy Caldwell, Carl J Ade
During an apneic event, sympathetic nerve activity increases resulting in subsequent increases in left ventricular afterload and myocardial work. It is unknown how cardiac mechanics are acutely impacted by the increased myocardial work during an apneic event. 10 healthy individuals (23 ± 3 yrs) performed multiple voluntary end-expiratory apnea (VEEA) maneuvers exposed to room air, while a subset (n=7) completed multiple VEEA exposed to hyperoxic air (100% FiO2). Beat-by-beat blood pressure, heart rate and stroke volume were measured continuously...
September 14, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28912181/hypertrophic-cardiomyopathy-genetics-pathogenesis-clinical-manifestations-diagnosis-and-therapy
#14
REVIEW
Ali J Marian, Eugene Braunwald
Hypertrophic cardiomyopathy (HCM) is a genetic disorder that is characterized by left ventricular hypertrophy unexplained by secondary causes and a nondilated left ventricle with preserved or increased ejection fraction. It is commonly asymmetrical with the most severe hypertrophy involving the basal interventricular septum. Left ventricular outflow tract obstruction is present at rest in about one third of the patients and can be provoked in another third. The histological features of HCM include myocyte hypertrophy and disarray, as well as interstitial fibrosis...
September 15, 2017: Circulation Research
https://www.readbyqxmd.com/read/28910144/ask1-inhibition-halts-disease-progression-in-preclinical-models-of-pulmonary-arterial-hypertension
#15
Grant R Budas, Mario Boehm, Baktybek Kojonazarov, Gayathri Viswanathan, Xia Tian, Swathi Veeroju, Tatyana Novoyatleva, Friedrich Grimminger, Ford Hinojosa-Kirschenbaum, Hossein A Ghofrani, Norbert Weissmann, Werner Seeger, John T Liles, Ralph T Schermuly
RATIONALE Progression of pulmonary arterial hypertension (PAH) is associated with pathologic remodeling of the pulmonary vasculature and the right ventricle (RV). Oxidative stress drives the remodeling process through activation of mitogenactivated protein kinases (MAPKs) which stimulate apoptosis, inflammation and fibrosis. OBJECTIVES We investigated whether pharmacological inhibition of the redoxsensitive apical MAPK Apoptosis Signal-Regulating Kinase 1 (ASK1) can halt the progression of pulmonary vascular and RV remodeling...
September 14, 2017: American Journal of Respiratory and Critical Care Medicine
https://www.readbyqxmd.com/read/28903938/atrial-fibrillation-in-acute-obstructive-sleep-apnea-autonomic-nervous-mechanism-and-modulation
#16
Lilei Yu, Xuefei Li, Bing Huang, Xiaoya Zhou, Menglong Wang, Liping Zhou, Guannan Meng, Yuhong Wang, Zhenya Wang, Jielin Deng, Hong Jiang
BACKGROUND: The mechanisms of atrial fibrillation (AF) induced by obstructive sleep apnea (OSA) are not completely understood. This study investigated the roles of the intrinsic and extrinsic cardiac autonomic nervous system in OSA-induced AF and provided noninvasive autonomic nervous modulation for the suppression of OSA-induced AF by using low-level transcutaneous electrical stimulation (LL-TS) of the auricular branch of the vagus nerve at the tragus. METHODS AND RESULTS: Eighteen dogs received tracheostomy under general anesthesia and were randomly divided into 3 groups: the OSA group (OSA was simulated via clamping of the endotracheal tube at end expiration for 1...
September 13, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28903763/troponin-as-ischemic-biomarker-is-related-with-all-three-echocardiographic-risk-factors-for-sudden-death-in-hypertrophic-cardiomyopathy-esc-guidelines-2014
#17
Rafał Hładij, Renata Rajtar-Salwa, Paweł Petkow Dimitrow
BACKGROUND: Sudden cardiac death (SCD) risk stratification is the most important preventive action in patients with hypertrophic cardiomyopathy (HCM). The identification of the ischemia biomarker high sensitive troponin I (hs-TnI) role for this arrhythmic disease may provide additional information for SCD risk stratification. The aim of the study was to compare echocardiographic parameters (prognostic for risk stratification of SCD in HCM) among two subgroups of HCM patients: with elevated hs-TnI versus non-elevated hs-TnI level...
September 13, 2017: Cardiovascular Ultrasound
https://www.readbyqxmd.com/read/28903498/from-the-cover-lifelong-exposure-of-c57bl-6n-male-mice-to-bisphenol-a-or-bisphenol-s-reduces-recovery-from-a-myocardial-infarction
#18
Amanda Kasneci, Jun Seong Lee, Tae Jin Yun, Jijun Shang, Shaun Lampen, Tamar Gomolin, Cheolho C Cheong, Lorraine E Chalifour
Bisphenol A (BPA) leaches from plastics to contaminate foodstuffs. Analogs, such as bisphenol S (BPS), are now used increasingly in manufacturing. Greater BPA exposure has been correlated with exacerbation of cardiovascular disease, including myocardial infarction (MI). To test the hypothesis that bisphenol exposure impairs cardiac healing, we exposed C57bl/6n mice to water containing 25ng/ml BPA or BPS from conception and surgically induced an MI in adult male progeny. Increased early death and cardiac dilation, and reduced cardiac function were found post-MI in BPA- and BPS-exposed mice...
September 1, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
https://www.readbyqxmd.com/read/28901395/role-of-matrix-metalloproteinase%C3%A2-7-and-apoptosis%C3%A2-associated-gene-expression-levels-in-the-pathogenesis-of-atrial-fibrosis-in-a-beagle-dog-model
#19
Min Jia, Zai-Bo Li, Lin Li, Hong-Tao Chu, Zhuang-Zhuang Li
The aim of the present study was to investigate the potential role of matrix metalloproteinase‑7 (MMP‑7) and apoptosis‑associated genes [TIMP metallopeptidase inhibitor 2(TIMP‑2), BCL2 associated X, apoptosis regulator (BAX) and BCL2, apoptosis regulator (BCL‑2)] in the pathogenesis of atrial fibrillation (AF) in a Beagle dog model. A total of 20 adult male Beagle dogs were randomly assigned into the AF group (n=10; Beagle dogs were treated by Burst stimulation to induce AF) and the control group (n=10; healthy Beagle dogs)...
August 31, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28900462/comparison-of-the-therapeutic-effects-of-acupuncture-at-pc6-and-st36-for-chronic-myocardial-ischemia
#20
Li Shi, Jiliang Fang, Jiping Zhao, Guiyong Liu, Qing Zhao, Jinling Zhang, Jinzhao Zhang, Bing Zhu, Fanrong Liang, Peijing Rong
We aimed to compare the differences of the effects on chronic myocardial ischemia (MI) of acupuncture at PC6 and ST36. The chronic MI model of minipigs was created by implanting an Ameroid constrictor on the left anterior descending coronary artery (LAD) and then two weeks' acupuncture was stimulated at PC6 or ST36, respectively. The results showed that both acupoints' stimulation decreased the serous cardiac troponin T (cTnT) and ischemia modified albumin (IMA) significantly and improved the ischemic ECG changes...
2017: Evidence-based Complementary and Alternative Medicine: ECAM
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