Intracardiac light catheter for rapid scanning transmural absorbance spectroscopy of perfused myocardium: measurement of myoglobin oxygenation and mitochondria redox state
In this study, surface scattering was minimized and transmural path length optimized by placing a light source within the left ventricular chamber while monitoring transmurally transmitted light at the epicardial surface. The custom-designed intrachamber light catheter was a flexible coaxial cable (2.42-Fr) terminated with an encapsulated side-firing LED of 1.8 x 0.8 mm, altogether similar in size to a Millar pressure catheter. The LED catheter had minimal impact on aortic flow and heart rate in Langendorff perfusion and did not impact stability of the left ventricule of the working heart. Changes in transmural absorbance ...
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Femnou, A. N., Kuzmiak-Glancy, S., Covian, R., Giles, A. V., Kay, M. W., Balaban, R. S. Tags: INNOVATIVE METHODOLOGY Source Type: research

Design and validation of a tissue bath 3-D printed with PLA for optically mapping suspended whole heart preparations
This article details three-dimensional printable equipment for use in suspended whole heart optical mapping experiments. This equipment is less expensive than conventional manufactured equipment as well as easily customizable to the experimentalist. The baths can be waterproofed using only a three-dimensional printer, acetone, a glass microscope slide, c-clamps, and adhesive. (Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Entz, M., King, D. R., Poelzing, S. Tags: INNOVATIVE METHODOLOGY Source Type: research

Hypertrophic cardiomyopathy mutation in cardiac troponin T (R95H) attenuates length-dependent activation in guinea pig cardiac muscle fibers
The central region of cardiac troponin T (TnT) is important for modulating the dynamics of muscle length-mediated cross-bridge recruitment. Therefore, hypertrophic cardiomyopathy mutations in the central region may affect cross-bridge recruitment dynamics to alter myofilament Ca2+ sensitivity and length-dependent activation of cardiac myofilaments. Given the importance of the central region of TnT for cardiac contractile dynamics, we studied if hypertrophic cardiomyopathy-linked mutation (TnTR94H)-induced effects on contractile function would be differently modulated by sarcomere length (SL). Recombinant wild-type TnT (TnT...
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Mickelson, A. V., Chandra, M. Tags: RESEARCH ARTICLE Source Type: research

Role of myeloperoxidase in abdominal aortic aneurysm formation: mitigation by taurine
This study demonstrates that MPO gene deletion or supplementation with the natural product taurine, which can scavenge MPO-generated oxidants, can prevent AAA formation, suggesting an attractive potential therapeutic strategy for AAA. (Source: AJP: Heart and Circulatory Physiology)
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Kim, H. W., Blomkalns, A. L., Ogbi, M., Thomas, M., Gavrila, D., Neltner, B. S., Cassis, L. A., Thompson, R. W., Weiss, R. M., Lindower, P. D., Blanco, V. M., McCormick, M. L., Daugherty, A., Fu, X., Hazen, S. L., Stansfield, B. K., Huo, Y., Fulton, D. J. Tags: RESEARCH ARTICLE Source Type: research

Small RNA-seq during acute maximal exercise reveal RNAs involved in vascular inflammation and cardiometabolic health: brief report
Exercise improves cardiometabolic and vascular function, although the mechanisms remain unclear. Our objective was to demonstrate the diversity of circulating extracellular RNA (ex-RNA) release during acute exercise in humans and its relevance to exercise-mediated benefits on vascular inflammation. We performed plasma small RNA sequencing in 26 individuals undergoing symptom-limited maximal treadmill exercise, with replication of our top candidate miRNA in a separate cohort of 59 individuals undergoing bicycle ergometry. We found changes in miRNAs and other ex-RNAs with exercise (e.g., Y RNAs and tRNAs) implicated in cardi...
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Shah, R., Yeri, A., Das, A., Courtright-Lim, A., Ziegler, O., Gervino, E., Ocel, J., Quintero- Pinzon, P., Wooster, L., Bailey, C. S., Tanriverdi, K., Beaulieu, L. M., Freedman, J. E., Ghiran, I., Lewis, G. D., Van Keuren-Jensen, K., Das, S. Tags: RESEARCH ARTICLE Source Type: research

Effect of increases in cardiac contractility on cerebral blood flow in humans
The effect of acute increases in cardiac contractility on cerebral blood flow (CBF) remains unknown. We hypothesized that the external carotid artery (ECA) downstream vasculature modifies the direct influence of acute increases in heart rate and cardiac function on CBF regulation. Twelve healthy subjects received two infusions of dobutamine [first a low dose (5 μg·kg–1·min–1) and then a high dose (15 μg·kg–1·min–1)] for 12 min each. Cardiac output, blood flow through the internal carotid artery (ICA) and ECA, and echocardiographic measurements were performed during ...
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Ogoh, S., Moralez, G., Washio, T., Sarma, S., Hieda, M., Romero, S. A., Cramer, M. N., Shibasaki, M., Crandall, C. G. Tags: RESEARCH ARTICLE Source Type: research

Hypoxia promotes primitive glycosaminoglycan-rich extracellular matrix composition in developing heart valves
During postnatal heart valve development, glycosaminoglycan (GAG)-rich valve primordia transform into stratified valve leaflets composed of GAGs, fibrillar collagen, and elastin layers accompanied by decreased cell proliferation as well as thinning and elongation. The neonatal period is characterized by the transition from a uterine environment to atmospheric O2, but the role of changing O2 levels in valve extracellular matrix (ECM) composition or morphogenesis is not well characterized. Here, we show that tissue hypoxia decreases in mouse aortic valves in the days after birth, concomitant with ECM remodeling and cell cycl...
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Amofa, D., Hulin, A., Nakada, Y., Sadek, H. A., Yutzey, K. E. Tags: RESEARCH ARTICLE Source Type: research

Diabetes increases the susceptibility to acute kidney injury after myocardial infarction through augmented activation of renal Toll-like receptors in rats
Acute kidney injury (AKI) after acute myocardial infarction (MI) worsens the prognosis of MI patients. Although type 2 diabetes mellitus (DM) is a major risk factor of AKI after MI, the underlying mechanism remains unclear. Here, we examined the roles of renal Toll-like receptors (TLRs) in the impact of DM on AKI after MI. MI was induced by coronary artery ligation in Otsuka-Long-Evans-Tokushima fatty (OLETF) rats, a rat DM model, and Long-Evans-Tokushima-Otsuka (LETO) rats, nondiabetic controls. Sham-operated rats served as no-MI controls. Renal mRNA levels of TLR2 and myeloid differentiation factor 88 (MyD88) were signif...
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Ohno, K., Kuno, A., Murase, H., Muratsubaki, S., Miki, T., Tanno, M., Yano, T., Ishikawa, S., Yamashita, T., Miura, T. Tags: RESEARCH ARTICLE Source Type: research

Temporal dynamics of cardiac hypertrophic growth in response to pressure overload
Hypertension is one of the most important risk factors of heart failure. In response to high blood pressure, the left ventricle manifests hypertrophic growth to ameliorate wall stress, which may progress into decompensation and trigger pathological cardiac remodeling. Despite the clinical importance, the temporal dynamics of pathological cardiac growth remain elusive. Here, we took advantage of the puromycin labeling approach to measure the relative rates of protein synthesis as a way to delineate the temporal regulation of cardiac hypertrophic growth. We first identified the optimal treatment conditions for puromycin in n...
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Wang, Y., Zhang, Y., Ding, G., May, H. I., Xu, J., Gillette, T. G., Wang, H., Wang, Z. V. Tags: RESEARCH ARTICLE Source Type: research

{alpha}1A-Subtype adrenergic agonist therapy for the failing right ventricle
Failure of the right ventricle (RV) is a serious disease with a poor prognosis and limited treatment options. Signaling by α1-adrenergic receptors (α1-ARs), in particular the α1A-subtype, mediate cardioprotective effects in multiple heart failure models. Recent studies have shown that chronic treatment with the α1A-subtype agonist A61603 improves function and survival in a model of left ventricular failure. The goal of the present study was to determine if chronic A61603 treatment is beneficial in a RV failure model. We used tracheal instillation of the fibrogenic antibiotic bleomycin in mice to ind...
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Cowley, P. M., Wang, G., Joshi, S., Swigart, P. M., Lovett, D. H., Simpson, P. C., Baker, A. J. Tags: RESEARCH ARTICLE Source Type: research

Glucose transporter 4-deficient hearts develop maladaptive hypertrophy in response to physiological or pathological stresses
In conclusion, GLUT4 is required for the maintenance of cardiac structure and function in response to physiological or pathological processes that increase energy demands, in part through secondary changes in mitochondrial metabolism and cellular stress survival pathways such as Akt. NEW & NOTEWORTHY Glucose transporter 4 (GLUT4) is required for myocardial adaptations to exercise, and its absence accelerates heart dysfunction after pressure overload. The requirement for GLUT4 may extend beyond glucose uptake to include defects in mitochondrial metabolism and survival signaling pathways that develop in its absence. Ther...
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Wende, A. R., Kim, J., Holland, W. L., Wayment, B. E., ONeill, B. T., Tuinei, J., Brahma, M. K., Pepin, M. E., McCrory, M. A., Luptak, I., Halade, G. V., Litwin, S. E., Abel, E. D. Tags: RESEARCH ARTICLE Source Type: research

Pharmacological and physiological assessment of serotonin formation and degradation in isolated preparations from mouse and human hearts
Using transgenic (TG) mice that overexpress the human serotonin (5-HT)4a receptor specifically in cardiomyocytes, we wanted to know whether 5-HT can be formed and degraded in the mammalian heart and whether this can likewise lead to inotropic and chronotropic effects in this TG model. We noted that the 5-HT precursor 5-hydroxy-tryptophan (5-HTP) can exert inotropic and chronotropic effects in cardiac preparations from TG mice but not from wild-type (WT) mice; similar results were found in human atrial preparations as well as in intact TG animals using echocardiography. Moreover, by immunohistochemistry we could detect 5-HT...
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Gergs, U., Jung, F., Buchwalow, I. B., Hofmann, B., Simm, A., Treede, H., Neumann, J. Tags: RESEARCH ARTICLE Source Type: research

Increased activity of the orexin system in the paraventricular nucleus contributes to salt-sensitive hypertension
The orexin system is involved in arginine vasopressin (AVP) regulation, and its overactivation has been implicated in hypertension. However, its role in salt-sensitive hypertension (SSHTN) is unknown. Here, we tested the hypothesis that hyperactivity of the orexin system in the paraventricular nucleus (PVN) contributes to SSHTN via enhancing AVP signaling. Eight-week-old male Dahl salt-sensitive (Dahl S) and age- and sex-matched Sprague-Dawley (SD) rats were placed on a high-salt (HS; 8% NaCl) or normal-salt (NS; 0.4% NaCl) diet for 4 wk. HS intake did not alter mean arterial pressure (MAP), PVN mRNA levels of orexin recep...
Source: AJP: Heart and Circulatory Physiology - December 1, 2017 Category: Cardiology Authors: Huber, M. J., Fan, Y., Jiang, E., Zhu, F., Larson, R. A., Yan, J., Li, N., Chen, Q.-H., Shan, Z. Tags: RESEARCH ARTICLE Source Type: research

Chronic hypertension increases aortic endothelial hydraulic conductivity by upregulating endothelial aquaporin-1 expression
Numerous studies have examined the role of aquaporins in osmotic water transport in various systems, but virtually none have focused on the role of aquaporin in hydrostatically driven water transport involving mammalian cells save for our laboratory’s recent study of aortic endothelial cells. Here, we investigated aquaporin-1 expression and function in the aortic endothelium in two high-renin rat models of hypertension, the spontaneously hypertensive genetically altered Wistar-Kyoto rat variant and Sprague-Dawley rats made hypertensive by two-kidney, one-clip Goldblatt surgery. We measured aquaporin-1 expression in a...
Source: AJP: Heart and Circulatory Physiology - November 6, 2017 Category: Cardiology Authors: Toussaint, J., Raval, C. B., Nguyen, T., Fadaifard, H., Joshi, S., Wolberg, G., Quarfordt, S., Jan, K.-m., Rumschitzki, D. S. Tags: RESEARCH ARTICLE Source Type: research

Exercise of obese mice induces cardioprotection and oxygen sparing in hearts exposed to high-fat load
This study therefore shows that exercise-induced cardioprotective effects are present under hyperlipidemic conditions and highlights the important role of myocardial energetics during ischemic stress. NEW & NOTEWORTHY The exercise-induced cardioprotective effects in obese hearts are present under hyperlipidemic conditions, comparable to circulating levels of FA occurring with an ischemic insult. Myocardial oxygen sparing is associated with this effect, despite the general notion that high fat can decrease cardiac efficiency. This highlights the role of myocardial energetics during ischemic stress. (Source: AJP: Heart a...
Source: AJP: Heart and Circulatory Physiology - November 6, 2017 Category: Cardiology Authors: Boardman, N. T., Hafstad, A. D., Lund, J., Rossvoll, L., Aasum, E. Tags: RESEARCH ARTICLE Source Type: research