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.

Mitochondria-regulated formation of endothelium-derived extracellular vesicles shifts the mediator of flow-induced vasodilation
In conclusion, eEVs have a biphasic effect, with higher doses impairing and lower doses shifting the mediator of FID from nitric oxide (NO) to hydrogen peroxide (H2O2). Despite differences in protein content, eEVs may alter vascular function in similar directions, regardless of the stimulus used for their formation. Furthermore, mitochondrial ROS production is required for the generation of these vesicles. NEW & NOTEWORTHY The vascular effect of endothelium-derived extracellular vesicles (eEVs) is biphasic, with higher doses decreasing the magnitude of flow-induced dilation (FID) compared with lower doses that shift th...
Source: AJP: Heart and Circulatory Physiology - May 15, 2017 Category: Cardiology Authors: Freed, J. K., Durand, M. J., Hoffmann, B. R., Densmore, J. C., Greene, A. S., Gutterman, D. D. Tags: RESEARCH ARTICLE Source Type: research

Sept7b is required for the subcellular organization of cardiomyocytes and cardiac function in zebrafish
Myofibrils made up of actin, myosin, and associated proteins generate the contractile force in muscle, and, consequently, mutations in these proteins may lead to heart failure. Septins are a conserved family of small GTPases that associate with actin filaments, microtubules, and cellular membranes. Despite the importance of septins in cytoskeleton organization, their role in cardiomyocyte organization and function is poorly characterized. Here, we show that septin 7 is expressed in both embryonic and adult zebrafish hearts and elucidate the physiological significance of sept7b, the zebrafish ortholog of human septin 7, in ...
Source: AJP: Heart and Circulatory Physiology - May 15, 2017 Category: Cardiology Authors: Dash, S. N., Narumanchi, S., Paavola, J., Perttunen, S., Wang, H., Lakkisto, P., Tikkanen, I., Lehtonen, S. Tags: RESEARCH ARTICLE Source Type: research

Impact of mild orthostatic stress on aortic-cerebral hemodynamic transmission: insight from the frequency domain
This study aims to determine whether acute systemic vasoconstriction affects the dynamic pulsatile hemodynamic transmission from the aorta to the brain. We applied a stepwise lower body negative pressure (LBNP) (–10, –20, and –30 mmHg) in 15 young men to induce systemic vasoconstriction. To elucidate the dynamic relationship between the changes in aortic pressure (AoP; estimated from the radial arterial pressure waveforms) and the cerebral blood flow velocity (CBFV) at the middle cerebral artery (via a transcranial Doppler), frequency-domain analysis characterized the beat-to-beat slow oscillation (0.02&n...
Source: AJP: Heart and Circulatory Physiology - May 15, 2017 Category: Cardiology Authors: Sugawara, J., Tomoto, T., Imai, T., Maeda, S., Ogoh, S. Tags: RESEARCH ARTICLE Source Type: research

Microvascular leakage in acute myocardial infarction: characterization by histology, biochemistry, and magnetic resonance imaging
Cardiac microvascular obstruction (MVO) after ischemia-reperfusion (I/R) has been well studied, but microvascular leakage (MVL) remains largely unexplored. We characterized MVL in the mouse I/R model by histology, biochemistry, and cardiac magnetic resonance (CMR) imaging. I/R was induced surgically in mice. MVL was determined by administrating the microvascular permeability tracer Evans blue (EB) and/or gadolinium-diethylenetriaminepentaacetic acid contrast. The size of MVL, infarction, and MVO in the heart was quantified histologically. Myocardial EB was extracted and quantified chromatographically. Serial CMR images wer...
Source: AJP: Heart and Circulatory Physiology - May 15, 2017 Category: Cardiology Authors: Gao, X.-M., Wu, Q.-Z., Kiriazis, H., Su, Y., Han, L.-P., Pearson, J. T., Taylor, A. J., Du, X.-J. Tags: RESEARCH ARTICLE Source Type: research

B cells and atherosclerosis
B cells have emerged as important immune cells in cardiovascular disease. Initial studies have suggested that B cells protect against atherosclerosis development. However, subsequent studies demonstrating aggravation of atherosclerosis by B-2 cells have shed light on the subset-dependent effects of B cells. Here, we review the literature that has led to our current understanding of B cell regulation of atherosclerosis, touching on the importance of subsets, local regulation, human translation, and therapeutic potential. (Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - May 15, 2017 Category: Cardiology Authors: Srikakulapu, P., McNamara, C. A. Tags: REVIEW Source Type: research

Immune checkpoint dysfunction in large and medium vessel vasculitis
Giant cell arteritis (GCA) is a granulomatous vasculitis of the aorta and its medium-sized branch vessels. CD4 T cells, macrophages, and dendritic cells (DCs) build granulomatous infiltrates that injure the vessel wall and elicit a maladaptive response to injury. Pathological consequences include fragmentation of elastic membranes, destruction of the medial layer, microvascular neoangiogenesis, massive outgrowth of myofibroblasts, and lumen-occlusive intimal hyperplasia. Antigens have been suspected to drive the local activation of vasculitogenic CD4 T cells, but recent data have suggested a more generalized defect in the ...
Source: AJP: Heart and Circulatory Physiology - May 15, 2017 Category: Cardiology Authors: Watanabe, R., Zhang, H., Berry, G., Goronzy, J. J., Weyand, C. M. Tags: REVIEW Source Type: research

Recording sympathetic nerve activity in conscious humans and other mammals: guidelines and the road to standardization
Over the past several decades, studies of the sympathetic nervous system in humans, sheep, rabbits, rats, and mice have substantially increased mechanistic understanding of cardiovascular function and dysfunction. Recently, interest in sympathetic neural mechanisms contributing to blood pressure control has grown, in part because of the development of devices or surgical procedures that treat hypertension by manipulating sympathetic outflow. Studies in animal models have provided important insights into physiological and pathophysiological mechanisms that are not accessible in human studies. Across species and among labora...
Source: AJP: Heart and Circulatory Physiology - May 15, 2017 Category: Cardiology Authors: Hart, E. C., Head, G. A., Carter, J. R., Wallin, B. G., May, C. N., Hamza, S. M., Hall, J. E., Charkoudian, N., Osborn, J. W. Tags: REVIEW Source Type: research

Guidelines in cardiovascular research, a first for the American Journal of Physiology-Heart and Circulatory Physiology
(Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - May 15, 2017 Category: Cardiology Authors: Zucker, I. H. Tags: EDITORIAL Source Type: research

Short-term regular aerobic exercise reduces oxidative stress produced by acute high intraluminal pressure in the adipose microvasculature
In conclusion, aerobic exercise prevents high pressure-induced vascular dysfunction through an improved redox environment in the adipose microvasculature. NEW & NOTEWORTHY We describe potential mechanisms contributing to aerobic exercise-conferred protection against high intravascular pressure. Subcutaneous adipose microvessels from exercise mice express less NADPH oxidase (NOX) II and more superoxide dismutase (SOD) and demonstrate less sensitivity to ANG II. In microvascular endothelial cells, shear stress reduced NOX II but did not influence SOD expression. Listen to this article’s corresponding podcast at htt...
Source: AJP: Heart and Circulatory Physiology - May 1, 2017 Category: Cardiology Authors: Robinson, A. T., Fancher, I. S., Sudhahar, V., Bian, J. T., Cook, M. D., Mahmoud, A. M., Ali, M. M., Ushio-Fukai, M., Brown, M. D., Fukai, T., Phillips, S. A. Tags: RESEARCH ARTICLE Source Type: research

Ultrasound detection of altered placental vascular morphology based on hemodynamic pulse wave reflection
Abnormally pulsatile umbilical artery (UA) Doppler ultrasound velocity waveforms are a hallmark of severe or early onset placental-mediated intrauterine growth restriction (IUGR), whereas milder late onset IUGR pregnancies typically have normal UA pulsatility. The diagnostic utility of these waveforms to detect placental pathology is thus limited and hampered by factors outside of the placental circulation, including fetal cardiac output. In view of these limitations, we hypothesized that these Doppler waveforms could be more clearly understood as a reflection phenomenon and that a reflected pulse pressure wave is present ...
Source: AJP: Heart and Circulatory Physiology - May 1, 2017 Category: Cardiology Authors: Rahman, A., Zhou, Y.-Q., Yee, Y., Dazai, J., Cahill, L. S., Kingdom, J., Macgowan, C. K., Sled, J. G. Tags: INNOVATIVE METHODOLOGY Source Type: research

Cardiovascular consequences of the inspiratory muscle metaboreflex: effects of age and sex
With inspiratory muscle metaboreflex activation, we hypothesized that, compared with their younger counterparts, older men and women would exhibit greater 1) increases in mean arterial pressure (MAP) and limb vascular resistance (LVR) and 2) decreases in limb blood flow (QL) but 3) no sex differences would be present in older adults. Sixteen young adults [8 young men (YM) and 8 young women (YW), 18–24 yr] and 16 older adults [8 older men (OM) and 8 older women (OW), 60–73 yr] performed inspiratory resistive breathing tasks (IRBTs) at 2% and 65% of their maximal inspiratory pressure. During the IRBTs, breathing ...
Source: AJP: Heart and Circulatory Physiology - May 1, 2017 Category: Cardiology Authors: Smith, J. R., Alexander, A. M., Hammer, S. M., Didier, K. D., Kurti, S. P., Broxterman, R. M., Barstow, T. J., Harms, C. A. Tags: RESEARCH ARTICLE Source Type: research

High-throughput screening identifies microRNAs that target Nox2 and improve function after acute myocardial infarction
In conclusion, our results show that miR-106b, miR-148b, and miR-204 were able to improve heart function after myocardial infarction in mice by targeting Nox2 and possibly altering inflammatory cytokine production. This screening system and delivery method could have broader implications for miRNA-mediated therapeutics for cardiovascular and other diseases. NEW & NOTEWORTHY NADPH oxidase (Nox)2 is a promising target for treating cardiovascular disease, but there are no specific inhibitors. Finding endogenous signals that can target Nox2 and other inflammatory molecules is of great interest. In this study, we used high-...
Source: AJP: Heart and Circulatory Physiology - May 1, 2017 Category: Cardiology Authors: Yang, J., Brown, M. E., Zhang, H., Martinez, M., Zhao, Z., Bhutani, S., Yin, S., Trac, D., Xi, J. J., Davis, M. E. Tags: RESEARCH ARTICLE Source Type: research

Temporal dissociation between the minimal distal-to-aortic pressure ratio and peak hyperemia during intravenous adenosine infusion
The present study sought to compare the temporal relation between maximal coronary flow (peak hyperemia) and minimal coronary-to-aortic pressure ratio (Pd/Pa) for intracoronary (IC) and intravenous (IV) adenosine administration. Peak hyperemia is assumed to coincide with the minimal Pd/Pa value. However, this has not been confirmed for systemic hemodynamic variations during IV adenosine infusion. Hemodynamic responses to IV and IC adenosine administration were obtained in 12 patients (14 lesions) using combined IC pressure and flow velocity measurements. A fluid dynamic model was used to predict the change in Pd/Pa for dif...
Source: AJP: Heart and Circulatory Physiology - May 1, 2017 Category: Cardiology Authors: Casadonte, L., Marques, K. M., Spaan, J. A. E., Siebes, M. Tags: RESEARCH ARTICLE Source Type: research

Angiotensin-(1-7) attenuates angiotensin II-induced cardiac hypertrophy via a Sirt3-dependent mechanism
The objectives of the present study were to investigate the effect of ANG-(1–7) on the development of cardiac hypertrophy and to identify the intracellular mechanism underlying this action of ANG-(1–7). Blood pressure and heart rate were recorded using radiotelemetry before and after chronic subcutaneous infusion of control (PBS), ANG II, ANG-(1–7), or ANG II + ANG-(1–7) for 4 wk in normotensive rats. Chronic administration of ANG-(1–7) did not affect either basal blood pressure or the ANG II-induced elevation in blood pressure. However, ANG-(1–7) significantly attenuated ANG II-induced ...
Source: AJP: Heart and Circulatory Physiology - May 1, 2017 Category: Cardiology Authors: Guo, L., Yin, A., Zhang, Q., Zhong, T., ORourke, S. T., Sun, C. Tags: RESEARCH ARTICLE Source Type: research

A novel role for miR-133a in centrally mediated activation of the renin-angiotensin system in congestive heart failure
An activated renin-angiotensin system (RAS) within the central nervous system has been implicated in sympathoexcitation during various disease conditions including congestive heart failure (CHF). In particular, activation of the RAS in the paraventricular nucleus (PVN) of the hypothalamus has been recognized to augment sympathoexcitation in CHF. We observed a 2.6-fold increase in angiotensinogen (AGT) in the PVN of CHF. To elucidate the molecular mechanism for increased expression of AGT, we performed in silico analysis of the 3'-untranslated region (3'-UTR) of AGT and found a potential binding site for microRNA (miR)-133a...
Source: AJP: Heart and Circulatory Physiology - May 1, 2017 Category: Cardiology Authors: Sharma, N. M., Nandi, S. S., Zheng, H., Mishra, P. K., Patel, K. P. Tags: RESEARCH ARTICLE Source Type: research