scholarly journals Inhibition of brain proinflammatory cytokine synthesis reduces hypothalamic excitation in rats with ischemia-induced heart failure

2008 ◽  
Vol 295 (1) ◽  
pp. H227-H236 ◽  
Author(s):  
Yu-Ming Kang ◽  
Zhi-Hua Zhang ◽  
Baojian Xue ◽  
Robert M. Weiss ◽  
Robert B. Felder
Keyword(s):  
Heart Failure ◽  
Hpa Axis ◽  
Proinflammatory Cytokines ◽  
Proinflammatory Cytokine ◽  
Left Ventricular ◽  
Prostaglandin E ◽  
Renin Angiotensin ◽  
Intracerebroventricular Infusion ◽  
Cytokine Synthesis ◽  
The Brain

The expression of proinflammatory cytokines increases in the hypothalamus of rats with heart failure (HF). The pathophysiological significance of this observation is unknown. We hypothesized that hypothalamic proinflammatory cytokines upregulate the activity of central neural systems that contribute to increased sympathetic nerve activity in HF, specifically, the brain renin-angiotensin system (RAS) and the hypothalamic-pituitary-adrenal (HPA) axis. Rats with HF induced by coronary ligation and sham-operated controls (SHAM) were treated for 4 wk with a continuous intracerebroventricular infusion of the cytokine synthesis inhibitor pentoxifylline (PTX, 10 μg/h) or artificial cerebrospinal fluid (VEH). In VEH-treated HF rats, compared with VEH-treated SHAM rats, the hypothalamic expression of proinflammatory cytokines was increased, along with key components of the brain RAS (renin, angiotensin-converting enzyme, angiotensin type 1 receptor) and corticotropin-releasing hormone, the central indicator of HPA axis activation, in the paraventricular nucleus (PVN) of the hypothalamus. The expression of other inflammatory/excitatory mediators (superoxide, prostaglandin E2) was also increased, along with evidence of chronic neuronal excitation in PVN. VEH-treated HF rats had higher plasma levels of norepinephrine, ANG II, interleukin (IL)-1β, and adrenocorticotropic hormone, increased left ventricular end-diastolic pressure, and increased wet lung-to-body weight ratio. With the exception of plasma IL-1β, an indicator of peripheral proinflammatory cytokine activity, all measures of neurohumoral excitation were significantly lower in HF rats treated with intracerebroventricular PTX. These findings suggest that the increase in brain proinflammatory cytokines observed in rats with ischemia-induced HF is functionally significant, contributing to neurohumoral excitation by activating brain RAS and the HPA axis.

Regulation of components of the brain and cardiac renin-angiotensin systems by 17β-estradiol after myocardial infarction in female rats

2006 ◽  
Vol 291 (1) ◽  
pp. R155-R162 ◽  
Author(s):  
Stephanie A. Dean ◽  
Junhui Tan ◽  
Roselyn White ◽  
Edward R. O’Brien ◽  
Frans H. H. Leenen
Keyword(s):  
Myocardial Infarction ◽  
Left Ventricular ◽  
Female Rats ◽  
Lv Function ◽  
Coronary Artery Ligation ◽  
Brain Nuclei ◽  
Renin Angiotensin ◽  
Lv Dysfunction ◽  
17Β Estradiol ◽  
The Brain

The present study tested the hypothesis that 17β-estradiol (E2) inhibits increases in angiotensin-converting enzyme (ACE) and ANG II type 1 receptor (AT1R) in the brain and heart after myocardial infarction (MI) and, thereby, inhibits development of left ventricular (LV) dysfunction after MI. Age-matched female Wistar rats were treated as follows: 1) no surgery (ovary intact), 2) ovariectomy + subcutaneous vehicle treatment (OVX + Veh), or 3) OVX + subcutaneous administration of a high dose of E2 (OVX + high-E2). After 2 wk, rats were randomly assigned to coronary artery ligation (MI) and sham operation groups and studied after 3 wk. E2 status did not affect LV function in sham rats. At 2–3 wk after MI, impairment of LV function was similar across MI groups, as measured by echocardiography and direct LV catheterization. LV ACE mRNA abundance and activity were increased severalfold in all MI groups compared with respective sham animals and to similar levels across MI groups. In most brain nuclei, ACE and AT1R densities increased after MI. Unexpectedly, compared with the respective sham groups the relative increase was clearest (20–40%) in OVX + high-E2 MI rats, somewhat less (10–15%) in ovary-intact MI rats, and least (<10–15%) in OVX + Veh MI rats. However, because in the sham group brain ACE and AT1R densities increased in the OVX + Veh rats and decreased in the OVX + high-E2 rats compared with the ovary-intact rats, actual ACE and AT1R densities in most brain nuclei were modestly higher (<20%) in OVX + Veh MI rats than in the other two MI groups. Thus E2 does not inhibit upregulation of ACE in the LV after MI and amplifies the percent increases in ACE and AT1R densities in brain nuclei after MI, despite E2-induced downregulation in sham rats. Consistent with these minor variations in the tissue renin-angiotensin system, during the initial post-MI phase, E2 appears not to enhance or hinder the development of LV dysfunction.

Abstract 1213: Cardiac Overexpression of Epac1 in Transgenic Mice Protects Heart from Lipopolysaccharide-induced Cardiac Dysfunction and Inhibits JAK-STAT Pathway

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Satoshi Okumura ◽  
Yunzhe Bai ◽  
Meihua Jin ◽  
Sayaka Suzuki ◽  
Akiko Kuwae ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cyclic Amp ◽  
Transgenic Mice ◽  
Cardiac Function ◽  
Proinflammatory Cytokines ◽  
Cardiac Dysfunction ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Ventricular Ejection Fraction ◽  
Stat Pathway

The sympathetic nervous system and proinflammatory cytokines are believed to play independent roles in the pathophysiology of heart failure. However, the recent identification of Epac (exchange protein activated by cyclic AMP), a new cyclic AMP-binding protein that directly activates Rap1, have implicated that there may be a potential cross talk between the sympathetic and cytokine signals. In order to examine the role of Epac in cytokine signal to regulate cardiac function, we have generated transgenic mice expressing the human Epac1 gene under the control of alpha-cardiac myosin heavy chain promoter (Epac1-TG), and examined their response in lipopolysaccharide (LPS)-induced cardiac dysfunction, a well established model for sepsis-induced cardiac dysfunction. Sepsis-induced cardiac dysfunction results from the production of proinflammatory cytokines. At baseline, left ventricular ejection fraction (LVEF) was similar (TG vs. NTG, 67±1.7 vs. 69±2.1%, n =7–9). The degree of cardiac hypertrophy (LV(mg)/tibia(mm)) was also similar at 3 months old (TG vs. NTG 4.0±0.1 vs. 4.2±0.1, n =5–6), but it became slightly but significantly greater in Epac1-TG at 5 month old (TG vs. NTG 4.9±0.1 vs. 4.4±0.1, p< 0.05, n =5–7). LPS (5mg/kg) elicited a significant and robust reduction of LVEF in both Epac1-TG and NTG, but the magnitude of this decrease was much less in Epac1-TG at 6 hr after injection (TG vs. NTG 48±2.4 vs. 57±1.8%, p< 0.01, n =6–9). At 24 hr after injection, cardiac function was restored to the baseline in both Epac1-TG and NTG. We also examined the activation of JAK-STAT pathway at 24 hr after injection. The tyrosine phosphorylation of STAT1 (Tyr701) and STAT3 (Tyr705) in LV, which is an indicator of STAT activation, was reduced to a greater degree in Epac1-TG by 31±8.8% ( p< 0.05, n =4) and 29±5.9% ( p< 0.05, n =7), respectively, relative to that in NTG. Taken together, Epac1 protects the heart from the cytokine-induced cardiac dysfunction, at least in part, through the inhibition of the JAK-STAT pathway, suggesting the beneficial role played by sympathetic signal to antagonize proinflammatory cytokine signal in heart failure.

Abstract 814: Atorvastatin Attenuates Oxidative Stress And Improves Neuronal Nitric Oxide Synthase In The Brain Stem Of Heart Failure Mice

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Joseph Francis ◽  
Li Yu ◽  
Anuradha Guggilam ◽  
Srinivas Sriramula ◽  
Irving H Zucker
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Myocardial Infarction ◽  
Heart Failure ◽  
Brain Stem ◽  
Mrna Expression ◽  
Natriuretic Peptide ◽  
Left Ventricular ◽  
Neuronal Nos ◽  
The Brain

3-Hydroxyl-3-methylglutaryl coenzyme A reductase inhibitors (statins) have been shown to reduce the incidence of myocardial infarction independent of their lipid-lowering effects. Nitric oxide (NO) in the central nervous system contributes to cardiovascular regulatory mechanisms. Imbalance between nitric oxide (NO) and superoxide anion (O 2 . − ) in the brain may contribute to enhanced sympathetic drive in heart failure (HF). This study was done to determine whether treatment with atorvastatin (ATS) ameliorates the imbalance between NO and O 2 . − production in the brain stem and contributes to improvement of left ventricular (LV) function. Methods and Results: Myocardial infarction (MI) was induced by ligation of the left coronary artery or sham surgery. Subsequently, mice were treated with ATS (10 μg/kg) (MI + ATS), or vehicle (MI + V). After 5 weeks, echocardiography revealed left ventricular dilatation in MI mice. Realtime RT-PCR indicated an increase in the mRNA expression of the LV hypertrophy markers, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). Neuronal NOS (nNOS) and endothelial NOS (eNOS) mRNA expression were significantly reduced, while that of NAD(P)H oxidase subunit (gp91phox) expression was elevated in the brain stem of MI mice. Compared with sham-operated mice, ATS-treated mice showed reduced cardiac dilatation, decreased ANP and BNP in the LV. ATS also reduced gp91phox expression and increased nNOS mRNA expression in the brain stem, while no changes in eNOS and iNOS were observed. Conclusion: These findings suggest that ATS reduces oxidative stress and increases neuronal NOS in the brain stem, and improves left ventricular function in heart failure.

Abstract 306: Proinflammatory Prostaglandin E Impairs Adrenergic Contractility in Animal Hearts

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Yang K Xiang
Keyword(s):  
Heart Failure ◽  
Plasma Membrane ◽  
Calcium Signaling ◽  
Contractile Response ◽  
Left Ventricular ◽  
Prostaglandin E ◽  
Intracellular Camp ◽  
Ventricular Contractility ◽  
Adrenergic Stimulation ◽  
Phosphodiesterase 4

Introduction: Inflammation is a major risk factor for heart failure; inflammatory prostaglandin E is elevated in myocardium, and has been associated with development of heart failure via cardiac LV remodeling, but the mechanisms remain unclear. Hypothesis: We hypothesize that proinflammatory prostaglandin signaling might affect Left ventricular contractility by directly impairing β-adrenergic (βAR) signaling. Methods and Results: Pretreatment with Prostaglandin E impairs intracellular PKA phosphorylation of substrates in myocardium and cardiac contractile responses under β-adrenergic stimulation. Both prostaglandin E and β-adrenergic agonist isoproterenol induce intracellular cAMP activities in myocytes. However, the cAMP signal under prostaglandin stimulation is confined along the plasma membrane whereas the cAMP signal under isoproterenol stimulation is distributed throughout the cells, including the intracellular sarcoplasmic reticulum (SR), a calcium storage compartment critical for myocyte calcium signaling and contractile response. Interestingly, the prostaglandin E-induced cAMP signal is sufficient for PKA activation, leading phosphorylation and activation of phosphodiesterase 4 on the plasma membrane, a group of enzymes associated with membrane βARs for cAMP degradation. Moreover, pretreatment of prostaglandin E prevents dissociation of phosphodiesterase 4 from βAR induced by isoproterenol, a step necessary for cAMP diffusion from the plasma membrane to the intracellular SR. Together, prostaglandin E induces activation of phosphodiesterase 4 in βAR complex and prevents the cAMP diffusion from the plasma membrane to the SR under isoproterenol stimulation, and inhibits calcium signaling and contractile response in myocytes and animal hearts. Conclusions: This study provides a novel mechanism underlying the phosphodiesterase-mediated signaling crosstalk between two neurohormonal stimulation in myocardium under chronic conditions, and suggests that proinflammatory prostaglandin signaling may impair β-adrenergic contractile in the development of heart failure.

Abstract 1375: Brain Renin Angiotensin Blockade Attenuates Cytokines and Oxidative Stress in the Paraventricular Nucleus of Hypothalamus and Decreases Sympathoexcitation in Heart Failure Rats

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Ying Ma ◽  
Yu-Ming Kang* ◽  
Zhi-Ming Yang ◽  
Joseph Francis*
Keyword(s):  
Oxidative Stress ◽  
Heart Failure ◽  
Paraventricular Nucleus ◽  
Cross Talk ◽  
Renin Angiotensin System ◽  
Heart Weight ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
The Brain ◽  
And Oxidative Stress

Introduction: Neurohumoral mechanisms play an important role in the pathophysiology of congestive heart failure (HF). Recent studies suggest that the brain renin angiotensin system (RAS) plays an important role in regulating body fluids and sympathetic drive in HF. In addition, it has been shown that there is cross talk between cytokines and RAS in cardiovascular disease. In this study we determined whether blockade of brain RAS attenuate inflammatory cytokines and oxidative stress in HF rats. Methods and Results: Adult male Sprague-Dawley rats were implanted with intracerebroventricular (ICV) cannulae and subjected to coronary artery ligation to induce HF and confirmed by echocardiography. Rats were treated with an angiotensin type 1 receptors (AT1-R) antagonist losartan (LOS, 20 μg/hr, ICV) or vehicle (VEH) for 4 weeks. At the end of the study, left ventricular (LV) function was measured by echocardiography and rats were sacrificed, and brain and plasma samples were collected for measurements of cytokines and superoxide using immunohistochemistry, Western blot and real time RT-PCR. HF rats induced significant increases in Nuclear Factor-kappaB (NF-κB) p50-positive neurons and activated microglia in the paraventricular nucleus (PVN) of hypothalamus, and TNF-α, IL-1β, IL-6 and NF-κB p50 in hypothalamus when compared with sham rats. These animals also had increased staining for dihydroethidium (DHE) and plasma levels of norepinephrine (NE), an indirect indicator of sympathetic activity. In contrast, ICV treatment with LOS attenuated cytokine expression and oxidative stress in the PVN and hypothalamus when compared with VEH treated HF rats. ICV treatment with LOS also reduced plasma NE levels, and proinflammatory cytokine, heart weight to body weight ratio with decreased LV end-diastolic pressure. Conclusions : These findings suggest the cross talk between the cytokines and renin angiotensin system within the brain contribute to sympatho-excitation in HF.

Brain “ouabain” and angiotensin II contribute to cardiac dysfunction after myocardial infarction

1999 ◽  
Vol 277 (5) ◽  
pp. H1786-H1792 ◽  
Author(s):  
Frans H. H. Leenen ◽  
Baoxue Yuan ◽  
Bing S. Huang
Keyword(s):  
Myocardial Infarction ◽  
Heart Failure ◽  
Renin Angiotensin System ◽  
Volume Overload ◽  
Angiotensin System ◽  
Sympathetic Hyperactivity ◽  
Renin Angiotensin ◽  
Fab Fragments ◽  
The Brain

In chronic heart failure (CHF), sympathetic activity increases in parallel with the impairment of left ventricle (LV) function, and sympathetic hyperactivity has been postulated to contribute to the progression of heart failure. In the brain, compounds with ouabain-like activity (“ouabain,” for brevity) and the renin-angiotensin system contribute to sympathetic hyperactivity in rats with CHF after myocardial infarction (MI). In the present studies, we assessed whether, in rats, chronic blockade of brain “ouabain” or the brain renin-angiotensin system inhibits the post-MI LV dysfunction. In rats, an MI was induced by acute coronary artery ligation. At either 0.5 or 4 wk post-MI, chronic treatment with Fab fragments for blocking brain “ouabain” or with losartan for blocking brain AT1 receptors was started and continued until 8 wk post-MI using osmotic minipumps connected to intracerebroventricular cannulas. At 8 wk post-MI, in conscious rats, LV pressures were measured at rest and in response to volume and pressure overload, followed by LV passive pressure-volume curves in vitro. At 8 wk post-MI, control MI rats exhibited clear increases in LV end-diastolic pressure (LVEDP) at rest and in response to pressure and volume overload. LV pressure-volume curves in vitro showed a marked shift to the right. Intravenous administration of the Fab fragments or losartan at rates used for central blockade did not affect these parameters. In contrast, chronic central blockade with either Fab fragments or losartan significantly lowered LVEDP at rest (only in 0.5- to 8-wk groups) and particularly in response to pressure or volume overload. LV dilation, as assessed from LV pressure-volume curves, was also significantly inhibited. These results indicate that chronic blockade of brain “ouabain” or brain AT1 receptors substantially inhibits development of LV dilation and dysfunction in rats post-MI.

Mineralocorticoid receptor antagonists in heart failure with reduced ejection fraction

2020 ◽  
Vol 15 (9) ◽  
pp. 1-9
Author(s):  
Kate O'Donovan
Keyword(s):  
Heart Failure ◽  
Cardiac Output ◽  
Adverse Effects ◽  
Ejection Fraction ◽  
Mineralocorticoid Receptor ◽  
Left Ventricular ◽  
Mineralocorticoid Receptor Antagonists ◽  
Renin Angiotensin Aldosterone System ◽  
Renin Angiotensin ◽  
Reduced Ejection Fraction

Heart failure with reduced ejection fraction is associated with decreased functional capacity, poor quality of life and increased mortality risk. The neurohormonal compensatory response to a reduced cardiac output is mainly comprised of the sympathetic nervous system, natriuretic peptides and the renin–angiotensin–aldosterone system, which attempt to maintain peripheral perfusion. The renin–angiotensin–aldosterone system is an integral mechanism in increasing afterload by promoting angiotensin II-mediated vasoconstriction and increasing preload via the secretion of aldosterone which causes sodium and water retention. Albeit compensatory mechanisms attempt to increase cardiac output and perfusion, their effects are maladaptive as left ventricular function deteriorates in response to an increased afterload, preload and ventricular remodelling. In an attempt to interrupt this vicious circle, first-line pharmacological therapy in the treatment of heart failure is beta blockade and inhibition of the renin–angiotensin–aldosterone system. Integral to this treatment strategy are mineralocorticoid receptor antagonists, also known as aldosterone antagonists. This class of drug inhibits the action of aldosterone, decreases preload and reduces left ventricular workload, thus preserving ventricular function. This translates into reduced mortality incidence, decreased episodes of hospitalisations for cardiac causes and improvement in clinical signs and symptoms. Although patient benefits are explicit, adverse effects such as hyperkalaemia and renal impairment are associated with this therapy. Regular patient follow up and monitoring for potential adverse effects and drug interactions are essential to the success of the therapy.

scholarly journals Neurotransmission to parasympathetic cardiac vagal neurons in the brain stem is altered with left ventricular hypertrophy-induced heart failure

2015 ◽  
Vol 309 (8) ◽  
pp. H1281-H1287 ◽  
Author(s):  
Edmund Cauley ◽  
Xin Wang ◽  
Jhansi Dyavanapalli ◽  
Ke Sun ◽  
Kara Garrott ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiovascular Diseases ◽  
Left Ventricular Hypertrophy ◽  
Cardiac Hypertrophy ◽  
Brain Stem ◽  
Ventricular Hypertrophy ◽  
Cardiac Activity ◽  
Left Ventricular ◽  
Parasympathetic Activity ◽  
The Brain

Hypertension, cardiac hypertrophy, and heart failure (HF) are widespread and debilitating cardiovascular diseases that affect nearly 23 million people worldwide. A distinctive hallmark of these cardiovascular diseases is autonomic imbalance, with increased sympathetic activity and decreased parasympathetic vagal tone. Recent device-based approaches, such as implantable vagal stimulators that stimulate a multitude of visceral sensory and motor fibers in the vagus nerve, are being evaluated as new therapeutic approaches for these and other diseases. However, little is known about how parasympathetic activity to the heart is altered with these diseases, and this lack of knowledge is an obstacle in the goal of devising selective interventions that can target and selectively restore parasympathetic activity to the heart. To identify the changes that occur within the brain stem to diminish the parasympathetic cardiac activity, left ventricular hypertrophy was elicited in rats by aortic pressure overload using a transaortic constriction approach. Cardiac vagal neurons (CVNs) in the brain stem that generate parasympathetic activity to the heart were identified with a retrograde tracer and studied using patch-clamp electrophysiological recordings in vitro. Animals with left cardiac hypertrophy had diminished excitation of CVNs, which was mediated both by an augmented frequency of spontaneous inhibitory GABAergic neurotransmission (with no alteration of inhibitory glycinergic activity) as well as a diminished amplitude and frequency of excitatory neurotransmission to CVNs. Opportunities to alter these network pathways and neurotransmitter receptors provide future targets of intervention in the goal to restore parasympathetic activity and autonomic balance to the heart in cardiac hypertrophy and other cardiovascular diseases.

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