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.

Prolonged sitting leg vasculopathy: contributing factors and clinical implications
Atherosclerotic peripheral artery disease primarily manifests in the medium- to large-sized conduit arteries of the lower extremities. However, the factors underlying this increased vulnerability of leg macrovasculature to disease are largely unidentified. On the basis of recent studies, we propose that excessive time spent in the sitting position and the ensuing reduction in leg blood flow-induced shear stress cause endothelial cell dysfunction, a key predisposing factor to peripheral artery disease. In particular, this review summarizes the findings from laboratory-based sitting studies revealing acute leg vascular dysfu...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Padilla, J., Fadel, P. J. Tags: REVIEW Source Type: research

Pathophysiology of cardiorenal syndrome in patients with heart failure: potential therapeutic targets
Despite the development of pharmacological inventions and new nonpharmacological techniques to prevent and treat heart failure (HF), the mortality rate in patients with symptomatic HF remains high. To conquer these difficulties, the pathophysiology of HF should be considered within a wide range of views. Given the diverse mechanisms of HF pathophysiology, renal and cardiac functions have close and complementary interconnections. Recent studies have suggested that communication between the kidney and heart through bidirectional pathways causes significant pathological changes. This review summarizes the pathophysiology of c...
Source: AJP: Heart and Circulatory Physiology - October 11, 2017 Category: Cardiology Authors: Takahama, H., Kitakaze, M. Tags: REVIEW Source Type: research

Temporal changes in the exercise pressor reflex in type 1 diabetic rats
We examined, in decerebrate male and female T1DM [streptozotocin (STZ)] and healthy control (CTL) rats, pressor and cardioaccelerator responses to isometric contraction of the hindlimb muscles during the early and late stages of the disease. STZ (50 mg/kg) was injected to induce diabetes, and experiments were conducted at 1, 3, and 6 wk after injection. On the day of the experiment, we statically contracted the hindlimb muscles by stimulating the sciatic nerve and measured changes in mean arterial pressure and heart rate. We found that the pressor but not cardioaccelerator response was exaggerated in STZ rats at 1 wk (STZ:...
Source: AJP: Heart and Circulatory Physiology - October 1, 2017 Category: Cardiology Authors: Grotle, A.-K., Garcia, E. A., Huo, Y., Stone, A. J. Tags: RAPID REPORT Source Type: research

Anomalous baroreflex functionality inherent in floxed and Cre-Lox mice: an overlooked physiological phenotype
The last two decades have seen the emergence of Cre-Lox recombination as one of the most powerful and versatile technologies for cell-specific genetic engineering of mammalian cells. Understandably, the primary concerns in the practice of Cre-Lox recombination are whether the predicted genome has been correctly modified and the targeted phenotypes expressed. Rarely are the physiological conditions of the animals routinely examined because the general assumption is that they are normal. Based on corroborative results from radiotelemetric recording, power spectral analysis, and magnetic resonance imaging/diffusion tensor ima...
Source: AJP: Heart and Circulatory Physiology - October 1, 2017 Category: Cardiology Authors: Tsai, C.-Y., Poon, Y.-Y., Chen, C.-H., Chan, S. H. H. Tags: RAPID REPORT Source Type: research

Intracoronary delivery of recombinant TIMP-3 after myocardial infarction: effects on myocardial remodeling and function
This study is the first to demonstrate that a relevant delivery approach (intracoronary) using rTIMP can alter the course of post-MI remodeling. NEW & NOTEWORTHY Myocardial ischemia and reperfusion injury remain significant causes of morbidity and mortality whereby alterations in the balance between matrix metalloproteinase and tissue inhibitor of metalloproteinase have been identified as contributory biological mechanisms. This novel translational study advances the concept of targeted delivery of recombinant proteins to modify adverse myocardial remodeling in ischemia-reperfusion injury. (Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - October 1, 2017 Category: Cardiology Authors: Barlow, S. C., Doviak, H., Jacobs, J., Freeburg, L. A., Perreault, P. E., Zellars, K. N., Moreau, K., Villacreses, C. F., Smith, S., Khakoo, A. Y., Lee, T., Spinale, F. G. Tags: RESEARCH ARTICLE Source Type: research

Uncovering novel roles for matrix metalloproteinases in preeclampsia
(Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - October 1, 2017 Category: Cardiology Authors: Foote, C. A., Martinez-Lemus, L. A. Tags: EDITORIAL FOCUS Source Type: research

5-HT causes splanchnic venodilation
Serotonin [5-hydroxytryptamine (5-HT)] causes relaxation of the isolated superior mesenteric vein, a splanchnic blood vessel, through activation of the 5-HT7 receptor. As part of studies designed to identify the mechanism(s) through which chronic (≥24 h) infusion of 5-HT lowers blood pressure, we tested the hypothesis that 5-HT causes in vitro and in vivo splanchnic venodilation that is 5-HT7 receptor dependent. In tissue baths for measurement of isometric contraction, the portal vein and abdominal inferior vena cava relaxed to 5-HT and the 5-HT1/7 receptor agonist 5-carboxamidotryptamine; relaxation was abolished by th...
Source: AJP: Heart and Circulatory Physiology - September 12, 2017 Category: Cardiology Authors: Seitz, B. M., Orer, H. S., Krieger-Burke, T., Darios, E. S., Thompson, J. M., Fink, G. D., Watts, S. W. Tags: RESEARCH ARTICLE Source Type: research

Regional heterogeneity in the mechanisms of myogenic tone in hamster arterioles
Myogenic tone is an important feature of arterioles and resistance arteries, but the mechanisms responsible for this hallmark characteristic remain unclear. We used pharmacological inhibitors to compare the roles played by phospholipase C (PLC; 10 μM U73122), inositol 1,4,5-trisphosphate receptors (IP3Rs; 100 μM 2-aminoethoxydiphenylborane), protein kinase C (10 μM bisindolylmaleimide I), angiotensin II type 1 receptors (1 μM losartan), Rho kinase (10 nM–30 μM Y27632 or 300 nM H1152), stretch-activated ion channels (10 nM–1 μM Gd3+ or 5 μM spider venom toxin GsMTx-4) and L-type voltage-gate...
Source: AJP: Heart and Circulatory Physiology - September 12, 2017 Category: Cardiology Authors: Jackson, W. F., Boerman, E. M. Tags: RESEARCH ARTICLE Source Type: research

Folic acid ingestion improves skeletal muscle blood flow during graded handgrip and plantar flexion exercise in aged humans
Skeletal muscle blood flow is attenuated in aged humans performing dynamic exercise, which is due, in part, to impaired local vasodilatory mechanisms. Recent evidence suggests that folic acid improves cutaneous vasodilation during localized and whole body heating through nitric oxide-dependent mechanisms. However, it is unclear whether folic acid improves vasodilation in other vascular beds during conditions of increased metabolism (i.e., exercise). The purpose of this study was to test the hypothesis that folic acid ingestion improves skeletal muscle blood flow in aged adults performing graded handgrip and plantar flexion...
Source: AJP: Heart and Circulatory Physiology - September 12, 2017 Category: Cardiology Authors: Romero, S. A., Gagnon, D., Adams, A. N., Moralez, G., Kouda, K., Jaffery, M. F., Cramer, M. N., Crandall, C. G. Tags: RESEARCH ARTICLE Source Type: research

The carotid baroreflex modifies the pressor threshold of the muscle metaboreflex in humans
The purpose of the present study was to test our hypothesis that unloading the carotid baroreceptors alters the threshold and gain of the muscle metaboreflex in humans. Ten healthy subjects performed a static handgrip exercise at 50% of maximum voluntary contraction. Contraction was sustained for 15, 30, 45, and 60 s and was followed by 3 min of forearm circulatory arrest, during which forearm muscular pH is known to decrease linearly with increasing contraction time. The carotid baroreceptors were unloaded by applying 0.1-Hz sinusoidal neck pressure (oscillating from +15 to +50 mmHg) during ischemia. We estimated the thre...
Source: AJP: Heart and Circulatory Physiology - September 12, 2017 Category: Cardiology Authors: Ichinose, M., Ichinose-Kuwahara, T., Watanabe, K., Kondo, N., Nishiyasu, T. Tags: RESEARCH ARTICLE Source Type: research

MicroRNA-124 controls human vascular smooth muscle cell phenotypic switch via Sp1
Phenotypic switch of vascular smooth muscle cells (VSMCs) plays an important role in the pathogenesis of atherosclerosis and aortic dissection. However, the mechanisms of phenotypic modulation are still unclear. MicroRNAs have emerged as important regulators of VSMC function. We recently found that microRNA-124 (miR-124) was downregulated in proliferative vascular diseases that were characterized by a VSMC phenotypic switch. Therefore, we speculated that the aberrant expression of miR-124 might play a critical role in human aortic VSMC phenotypic switch. Using quantitative RT-PCR, we found that miR-124 was dramatically dow...
Source: AJP: Heart and Circulatory Physiology - September 12, 2017 Category: Cardiology Authors: Tang, Y., Yu, S., Liu, Y., Zhang, J., Han, L., Xu, Z. Tags: RESEARCH ARTICLE Source Type: research

Cardiac fibroblast transcriptome analyses support a role for interferogenic, profibrotic, and inflammatory genes in anti-SSA/Ro-associated congenital heart block
This study provides in vivo and in vitro transcriptome-support that injury may be mediated by an effect of Type I Interferon on fetal fibroblasts. (Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - September 12, 2017 Category: Cardiology Authors: Clancy, R. M., Markham, A. J., Jackson, T., Rasmussen, S. E., Blumenberg, M., Buyon, J. P. Tags: RESEARCH ARTICLE Source Type: research

Remodeling of repolarization and arrhythmia susceptibility in a myosin-binding protein C knockout mouse model
In conclusion, decrease in repolarizing K+ currents in MyBPC KO ventricular myocytes contributes to AP and corrected QT interval prolongation and could account for the arrhythmia susceptibility. NEW & NOTEWORTHY Ventricular myocytes isolated from the myosin-binding protein C knockout hypertrophic cardiomyopathy mouse model demonstrate decreased repolarizing K+ currents and action potential and QT interval prolongation, linking cellular repolarization abnormalities with arrhythmia susceptibility and the risk for sudden cardiac death in hypertrophic cardiomyopathy. (Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - September 12, 2017 Category: Cardiology Authors: Toib, A., Zhang, C., Borghetti, G., Zhang, X., Wallner, M., Yang, Y., Troupes, C. D., Kubo, H., Sharp, T. E., Feldsott, E., Berretta, R. M., Zalavadia, N., Trappanese, D. M., Harper, S., Gross, P., Chen, X., Mohsin, S., Houser, S. R. Tags: RESEARCH ARTICLE Source Type: research

Revisiting protein acetylation and myocardial fatty acid oxidation
(Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - September 12, 2017 Category: Cardiology Authors: Al Batran, R., Ussher, J. R. Tags: EDITORIAL FOCUS Source Type: research

Metabolic remodeling in hypertrophied and failing myocardium: a review
The energy starvation hypothesis proposes that maladaptive metabolic remodeling antedates, initiates, and maintains adverse contractile dysfunction in heart failure (HF). Better understanding of the cardiac metabolic phenotype and metabolic signaling could help identify the role metabolic remodeling plays within HF and the conditions known to transition toward HF, including "pathological" hypertrophy. In this review, we discuss metabolic phenotype and metabolic signaling in the contexts of pathological hypertrophy and HF. We discuss the significance of alterations in energy supply (substrate utilization, oxidative capacity...
Source: AJP: Heart and Circulatory Physiology - September 12, 2017 Category: Cardiology Authors: Peterzan, M. A., Lygate, C. A., Neubauer, S., Rider, O. J. Tags: REVIEW Source Type: research