In this Issue
January 2017; volume 312, issue 1
REVIEW | Advances in Cardiovascular Geroscience
REVIEW | Cardiovascular Actions of Hydrogen Sulfide and Other Gasotransmitters
RESEARCH ARTICLE | Cardiac Excitation and Contraction
- Acute exposure to progesterone attenuates cardiac contraction by modifying myofilament calcium sensitivity in the female mouse heart
We investigated myocardial effects of acute application of progesterone. In females, but not males, progesterone attenuates and slows cardiomyocyte contraction with no effect on calcium transients. Progesterone also reduces myofilament calcium sensitivity in female hearts. This may adversely affect heart function, especially when serum progesterone levels are high in pregnancy.
RESEARCH ARTICLE | Cardiovascular Neurohormonal Regulation
- Myocardial interstitial levels of serotonin and its major metabolite 5-hydroxyindole acetic acid during ischemia-reperfusion
By monitoring myocardial interstitial levels of 5-HT and its metabolite, 5-hydroxyindole acetic acid, we investigated 5-HT kinetics during myocardial ischemia-reperfusion. 5-HT accumulates but 5-HT degradation is suppressed during ischemia. After reperfusion, 5-HT degradation is enhanced and this degradation is dependent on monoamine oxidase activity but not the fluoxetine-sensitive uptake transporter.
RESEARCH ARTICLES | Integrative Cardiovascular Physiology and Pathophysiology
- Exaggerated coronary vasoconstriction limits muscle metaboreflex-induced increases in ventricular performance in hypertension
We found that metaboreflex-induced increases in coronary blood flow and ventricular contractility are attenuated in hypertension. α1-Adrenergic blockade restored these parameters toward normal levels. These findings indicate that the primary mechanism mediating impaired metaboreflex-induced increases in ventricular function in hypertension is accentuated coronary vasoconstriction.
- Prediction of hemodynamics under left ventricular assist device
Hemodynamic response to left ventricular assist device (LVAD) has not been quantitatively investigated. This is the first report of quantitative prediction of the hemodynamics on LVAD using circulatory equilibrium framework. The validated framework allows us to simulate the impact of LVAD on right atrial pressure under various right ventricular functions.
- Acute limb heating improves macro- and microvascular dilator function in the leg of aged humans
We demonstrate that lower limb heating acutely improves macro- and microvascular dilator function within the atherosclerotic prone vasculature of the leg in aged adults. These findings provide evidence for a potential therapeutic use of chronic lower limb heating to improve vascular health in primary aging and various disease conditions.
- Estrogen receptor antagonism exacerbates cardiac structural and functional remodeling in female rats
We assessed the estrogen receptor (ER) dependence of female-specific cardioprotection using a rat model of chronic volume-overload stress. ER antagonism worsened ventricular wall stress, ventricular dilation, and cardiac dysfunction induced by volume overload. Further, blocking ERs resulted in cardiac remodeling and functional changes similar to that previously found in ovariectomized rats.
- Dynamical mechanisms of phase-2 early afterdepolarizations in human ventricular myocytes: insights from bifurcation analyses of two mathematical models
We investigated mechanisms of phase-2 early afterdepolarization (EAD) by bifurcation analyses of human ventricular myocyte (HVM) models. EAD formation in paced HVMs basically depended on bifurcation phenomena in nonpaced HVMs but was strongly affected by intracellular ion concentrations in stationary and dynamic states. EAD generation did not necessarily require IKs.
- Lifelong quercetin enrichment and cardioprotection in Mdx/Utrn+/− mice
The current investigation provides first time evidence that quercetin provides physiological cardioprotection against dystrophic pathology and is associated with improved spontaneous physical activity. Secondary findings suggest that quercetin-dependent outcomes are in part due to PGC-1α pathway activation.
RESEARCH ARTICLES | Muscle Mechanics and Ventricular Function
- Cardiomyopathy-related mutation (A30V) in mouse cardiac troponin T divergently alters the magnitude of stretch activation in α- and β-myosin heavy chain fibers
The differential impact of α- and β-myosin heavy chain (MHC) on contractile dynamics causes a mutant cardiac troponin T (TnTA30V) to differently modulate cardiac contractile function. TnTA30V attenuated Ca2+-activated maximal tension and length-mediated cross-bridge recruitment against α-MHC but augmented these parameters against β-MHC, suggesting divergent contractile phenotypes.
- Hyperglycemia induces defective Ca2+ homeostasis in cardiomyocytes
We have investigated the effects of hyperglycemia on cardiomyocyte physiology and ventricular function. Our results indicate that defective Ca2+ handling is a critical component of the progressive deterioration of cardiac performance of the diabetic heart.
RESEARCH ARTICLES | Vascular Biology and Microcirculation
- Investigating the extremes of the continuum of paracrine functions in CD34−/CD31+ CACs across diverse populations
S100A8 and S100A9 proteins in concentrations secreted by CD34–/CD31+ circulating angiogenic cells (CACs) with impaired function reduce endothelial cell capillary-like network formation. These effects appear to be mediated by Toll-like receptor 4 and are absent with S100A8 and S100A9 in concentrations secreted by healthy CD34–/CD31+ CACs.
- Positive versus negative effects of VEGF165 on Ca2+ signaling and NO production in human endothelial cells
In this manuscript, we show that VEGF levels associated with preeclampsia are a net negative contributor to potential vasodilator production in both a human ex vivo and in vitro endothelial cell model. Therefore, pharmacological targeting of VEGF-stimulated signaling pathways could be a novel treatment modality for preeclampsia-related hypertension.
- Interruption of perivascular sympathetic nerves of cerebral arteries offers neuroprotection against ischemia
Interruption of the perivascular sympathetic nerves can alleviate CA-induced hypoperfusion and neuronal cell death in the CA1 region of the hippocampus to enhance functional learning and memory.