AJP: Heart and Circulatory Physiology This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Mechanical behavior and matrisome gene expression in the aneurysm-prone thoracic aorta of newborn lysyl oxidase knockout mice
Mutations in lysyl oxidase (LOX) are associated with thoracic aortic aneurysm and dissection (TAAD). Mice that do not express Lox (Lox–/–) die soon after birth and have 60% and 40% reductions in elastin- and collagen-specific cross-links, respectively. LOX inactivation could also change the expression of secreted factors, the structural matrix, and matrix-associated proteins that constitute the aortic matrisome. We hypothesized that absence of Lox will change the mechanical behavior of the aortic wall because of reduced elastin and collagen cross-linking and alter the expression levels of matrisome and smooth m...
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Staiculescu, M. C., Kim, J., Mecham, R. P., Wagenseil, J. E. Tags: RESEARCH ARTICLE Source Type: research

Metabolism and acetylation contribute to leucine-mediated inhibition of cardiac glucose uptake
High plasma leucine levels strongly correlate with type 2 diabetes. Studies of muscle cells have suggested that leucine alters the insulin response for glucose transport by activating an insulin-negative feedback loop driven by the mammalian target of rapamycin/p70 ribosomal S6 kinase (mTOR/p70S6K) pathway. Here, we examined the molecular mechanism involved in leucine’s action on cardiac glucose uptake. Leucine was indeed able to curb glucose uptake after insulin stimulation in both cultured cardiomyocytes and perfused hearts. Although leucine activated mTOR/p70S6K, the mTOR inhibitor rapamycin did not prevent leucin...
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Renguet, E., Ginion, A., Gelinas, R., Bultot, L., Auquier, J., Robillard Frayne, I., Daneault, C., Vanoverschelde, J.-L., Des Rosiers, C., Hue, L., Horman, S., Beauloye, C., Bertrand, L. Tags: RESEARCH ARTICLE Source Type: research

Spinal cord stimulation reduces ventricular arrhythmias during acute ischemia by attenuation of regional myocardial excitability
In conclusion, in a porcine model of acute ventricular ischemia, SCS reduced regional myocardial sympathoexcitation, decreased ventricular arrhythmias, and improved myocardial function. SCS decreased sympathetic nerve activation locally in the ischemic myocardium with no effect observed in the normal myocardium, thus providing mechanistic insights into the antiarrhythmic and myocardial protective effects of SCS. NEW & NOTEWORTHY In a porcine model of ventricular ischemia, spinal cord stimulation decreased sympathetic nerve activation regionally in ischemic myocardium with no effect on normal myocardium, demonstrating t...
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Howard-Quijano, K., Takamiya, T., Dale, E. A., Kipke, J., Kubo, Y., Grogan, T., Afyouni, A., Shivkumar, K., Mahajan, A. Tags: RESEARCH ARTICLE Source Type: research

Right atrial pressure and venous return during cardiopulmonary bypass
The relevance of right atrial pressure (RAP) as the backpressure for venous return (QVR) and mean systemic filling pressure as upstream pressure is controversial during dynamic changes of circulation. To examine the immediate response of QVR (sum of caval vein flows) to changes in RAP and pump function, we used a closed-chest, central cannulation, heart bypass porcine preparation (n = 10) with venoarterial extracorporeal membrane oxygenation. Mean systemic filling pressure was determined by clamping extracorporeal membrane oxygenation tubing with open or closed arteriovenous shunt at euvolemia, volume expansion (9.75 ml/kg...
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Moller, P. W., Winkler, B., Hurni, S., Heinisch, P. P., Bloch, A., Sondergaard, S., Jakob, S. M., Takala, J., Berger, D. Tags: RESEARCH ARTICLE Source Type: research

Experimental cardiac radiation exposure induces ventricular diastolic dysfunction with preserved ejection fraction
Breast cancer radiotherapy increases the risk of heart failure with preserved ejection fraction (HFpEF). Cardiomyocytes are highly radioresistant, but radiation specifically affects coronary microvascular endothelial cells, with subsequent microvascular inflammation and rarefaction. The effects of radiation on left ventricular (LV) diastolic function are poorly characterized. We hypothesized that cardiac radiation exposure may result in diastolic dysfunction without reduced EF. Global cardiac expression of the sodium-iodide symporter (NIS) was induced by cardiotropic gene (adeno-associated virus serotype 9) delivery to 5-w...
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Saiki, H., Moulay, G., Guenzel, A. J., Liu, W., Decklever, T. D., Classic, K. L., Pham, L., Chen, H. H., Burnett, J. C., Russell, S. J., Redfield, M. M. Tags: RESEARCH ARTICLE Source Type: research

GBT1118, a potent allosteric modifier of hemoglobin O2 affinity, increases tolerance to severe hypoxia in mice
In conclusion, increased Hb O2 affinity enhanced physiological tolerance to hypoxia, as evidenced by improved hemodynamics and tissue oxygenation. Therefore, pharmacologically induced increases in Hb O2 affinity become a potential therapeutic approach to improve tissue oxygenation in pulmonary diseases characterized by severe hypoxemia. NEW & NOTEWORTHY This study establishes that pharmacological modification of hemoglobin O2 affinity can be a promising and novel therapeutic strategy for the treatment of hypoxic hypoxia and paves the way for the clinical development of molecules that prevent hypoxemia. (Source: AJP: He...
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Dufu, K., Yalcin, O., Ao-ieong, E. S. Y., Hutchaleelala, A., Xu, Q., Li, Z., Vlahakis, N., Oksenberg, D., Lehrer-Graiwer, J., Cabrales, P. Tags: RESEARCH ARTICLE Source Type: research

EET intervention on Wnt1, NOV, and HO-1 signaling prevents obesity-induced cardiomyopathy in obese mice
We have previously reported that epoxyeicosatrienoic acid (EET) has multiple beneficial effects on vascular function; in addition to its antiapoptotic action, it increases insulin sensitivity and inhibits inflammation. To uncover the signaling mechanisms by which EET reduces cardiomyopathy, we hypothesized that EET infusion might ameliorate obesity-induced cardiomyopathy by improving heme oxygenase (HO)-1, Wnt1, thermogenic gene levels, and mitochondrial integrity in cardiac tissues and improved pericardial fat phenotype. EET reduced levels of fasting blood glucose and proinflammatory adipokines, including nephroblastoma o...
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Cao, J., Singh, S. P., McClung, J. A., Joseph, G., Vanella, L., Barbagallo, I., Jiang, H., Falck, J. R., Arad, M., Shapiro, J. I., Abraham, N. G. Tags: RESEARCH ARTICLE Source Type: research

Cervical vagus nerve stimulation augments spontaneous discharge in second- and higher-order sensory neurons in the rat nucleus of the solitary tract
Vagus nerve stimulation (VNS) currently treats patients with drug-resistant epilepsy, depression, and heart failure. The mild intensities used in chronic VNS suggest that primary visceral afferents and central nervous system activation are involved. Here, we measured the activity of neurons in the nucleus of the solitary tract (NTS) in anesthetized rats using clinically styled VNS. Our chief findings indicate that VNS at threshold bradycardic intensity activated NTS neuron discharge in one-third of NTS neurons. This VNS directly activated only myelinated vagal afferents projecting to second-order NTS neurons. Most VNS-indu...
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Beaumont, E., Campbell, R. P., Andresen, M. C., Scofield, S., Singh, K., Libbus, I., KenKnight, B. H., Snyder, L., Cantrell, N. Tags: RESEARCH ARTICLE Source Type: research

{beta}-Adrenergic receptor stimulation inhibits proarrhythmic alternans in postinfarction border zone cardiomyocytes: a computational analysis
The border zone (BZ) of the viable myocardium adjacent to an infarct undergoes extensive autonomic and electrical remodeling and is prone to repolarization alternans-induced cardiac arrhythmias. BZ remodeling processes may promote or inhibit Ca2+ and/or repolarization alternans and may differentially affect ventricular arrhythmogenesis. Here, we used a detailed computational model of the canine ventricular cardiomyocyte to study the determinants of alternans in the BZ and their regulation by β-adrenergic receptor (β-AR) stimulation. The BZ model developed Ca2+ transient alternans at slower pacing cycle lengths th...
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Tomek, J., Rodriguez, B., Bub, G., Heijman, J. Tags: RESEARCH ARTICLE Source Type: research

Age or ischemia uncouples the blood flow response, tissue acidosis, and direct current potential signature of spreading depolarization in the rat brain
Spreading depolarization (SD) events contribute to lesion maturation in the acutely injured human brain. Neurodegeneration related to SD is thought to be caused by the insufficiency of the cerebral blood flow (CBF) response; yet the mediators of the CBF response, or their deficiency in the aged or ischemic cerebral cortex, remain the target of intensive research. Here, we postulated that tissue pH effectively modulates the magnitude of hyperemia in response to SD, the coupling of which is prone to be dysfunctional in the aged or ischemic cerebral cortex. To test this hypothesis, we conducted systematic correlation analysis...
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Menyhart, A., Zölei-Szenasi, D., Puskas, T., Makra, P., Bari, F., Farkas, E. Tags: RESEARCH ARTICLE Source Type: research

Are EETs at the heart of the b"EET" in obesity-induced cardiomyopathy?
(Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Dellsperger, K. C. Tags: EDITORIAL FOCUS Source Type: research

Radiation-induced HFpEF model as a potential tool for the exploration of novel therapeutic targets
(Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Tsukamoto, O., Kitakaze, M. Tags: EDITORIAL FOCUS Source Type: research

State-space representation of the extended Guyton's model
(Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Kamiya, A., Hayama, Y., Shimizu, S., Kawada, T. Tags: EDITORIAL FOCUS Source Type: research

Autophagy modulation: a potential therapeutic approach in cardiac hypertrophy
Autophagy is an evolutionarily conserved process used by the cell to degrade cytoplasmic contents for quality control, survival for temporal energy crisis, and catabolism and recycling. Rapidly increasing evidence has revealed an important pathogenic role of altered activity of the autophagosome-lysosome pathway (ALP) in cardiac hypertrophy and heart failure. Although an early study suggested that cardiac autophagy is increased and that this increase is maladaptive to the heart subject to pressure overload, more recent reports have overwhelmingly supported that myocardial ALP insufficiency results from chronic pressure ove...
Source: AJP: Heart and Circulatory Physiology - August 11, 2017 Category: Cardiology Authors: Wang, X., Cui, T. Tags: REVIEW Source Type: research