Heart failure (HF) is a leading cause of morbidity and mortality, often driven by prolonged exposure to pathological stimuli such as pressure and volume overload. These factors contribute to excessive oxidative stress, adverse cardiac remodeling, and dysregulation of the nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate (NO-sGC-cGMP) signaling pathway. Given the urgent need for effective treatments, this study investigated the potential of sGC stimulators to mitigate HF progression. We utilized male hypertensive Ren-2 transgenic (TGR) rats and a volume-overload HF model induced by an aortocaval fistula (ACF). Rats received the sGC stimulator BAY 41-8543 (3 mg/kg/day) for 30 weeks, while normotensive Hannover Sprague-Dawley rats served as controls. At the study endpoint (40 weeks of age), left ventricular tissue was analyzed using mass spectrometry, Western blotting, and histological assessment. TGR rats treated with sGC stimulators exhibited a significant increase in key antioxidant proteins (SOD1, CH10, ACSF2, NDUS1, DHE3, GSTM2, and PCCA), suggesting enhanced resistance to oxidative stress. However, sGC stimulator treatment also upregulated extracellular matrix remodeling markers (MMP-2, TGF-β, and SMAD2/3), which are typically associated with fibrosis. Despite this, Masson's trichrome staining revealed reduced collagen deposition in both TGR and TGR-ACF rats receiving sGC stimulators. Notably, all untreated TGR-ACF rats succumbed before the study endpoint, preventing direct assessment of sGC stimulator effects in advanced HF. These findings highlight the therapeutic potential of sGC stimulators in HF, particularly through their antioxidant effects. However, their concurrent influence on fibrosis warrants further investigation to optimize treatment strategies.

• Keywords
• heart failure with reduced ejection fraction, reactive oxygen/nitrogen species, renin‐angiotensin system, soluble guanylate cyclase stimulator,
• MeSH
• Guanylyl Cyclase C Agonists * pharmacology   therapeutic use   MeSH
• Rats MeSH
• Disease Models, Animal MeSH
• Morpholines MeSH
• Oxidative Stress drug effects   MeSH
• Rats, Sprague-Dawley MeSH
• Rats, Transgenic MeSH
• Pyrazoles * pharmacology   therapeutic use   MeSH
• Pyrimidines * pharmacology   therapeutic use   MeSH
• Ventricular Remodeling drug effects   MeSH
• Soluble Guanylyl Cyclase * metabolism   MeSH
• Heart Failure * drug therapy   etiology   physiopathology   metabolism   pathology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Guanylyl Cyclase C Agonists * MeSH
• BAY 41-8543 MeSH Browser
• Morpholines MeSH
• Pyrazoles * MeSH
• Pyrimidines * MeSH
• Soluble Guanylyl Cyclase * MeSH

Renal nerves play a critical role in cardiorenal interactions. Renal denervation (RDN) improved survival in some experimental heart failure (HF) models. It is not known whether these favorable effects are indirect, explainable by a decrease in vascular afterload, or diminished neurohumoral response in the kidneys, or whether RDN procedure per se has direct myocardial effects in the failing heart. To elucidate mechanisms how RDN affects failing heart, we studied load-independent indexes of ventricular function, gene markers of myocardial remodeling, and cardiac sympathetic signaling in HF, induced by chronic volume overload (aorto-caval fistula, ACF) of Ren2 transgenic rats. Volume overload by ACF led to left ventricular (LV) hypertrophy and dysfunction, myocardial remodeling (upregulated Nppa, MYH 7/6 genes), increased renal and circulating norepinephrine (NE), reduced myocardial NE content, increased monoaminoxidase A (MAO-A), ROS production and decreased tyrosine hydroxylase (+) nerve staining. RDN in HF animals decreased congestion in the lungs and the liver, improved load-independent cardiac function (Ees, PRSW, Ees/Ea ratio), without affecting arterial elastance or LV pressure, reduced adverse myocardial remodeling (Myh 7/6, collagen I/III ratio), decreased myocardial MAO-A and inhibited renal neprilysin activity. RDN increased myocardial expression of acetylcholinesterase (Ache) and muscarinic receptors (Chrm2), decreased circulating and renal NE, but increased myocardial NE content, restoring so autonomic control of the heart. These changes likely explain improvements in survival after RDN in this model. The results suggest that RDN has remote, load-independent and favorable intrinsic myocardial effects in the failing heart. RDN therefore could be a useful therapeutic strategy in HF.

• Keywords
• Heart failure, Norepinephrine, Renal denervation, Sympathetic nervous system, Volume overload,
• MeSH
• Rats MeSH
• Kidney * innervation   metabolism   MeSH
• Disease Models, Animal * MeSH
• Myocardium * metabolism   MeSH
• Norepinephrine * blood   metabolism   MeSH
• Rats, Transgenic * MeSH
• Ventricular Remodeling physiology   MeSH
• Heart innervation   physiopathology   MeSH
• Heart Failure * physiopathology   metabolism   MeSH
• Sympathectomy MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Norepinephrine * MeSH

While phosphodiesterase-5 inhibition (PED5i) may prevent hypertrophy and failure in pressure-overloaded heart in an experimental model, the impact of PDE5i on volume-overload (VO)-induced hypertrophy is unknown. It is also unclear whether the hypertrophied right ventricle (RV) and left ventricle (LV) differ in their responsiveness to long-term PDE5i and if this therapy affects renal function. The goal of this study was to elucidate the effect of PDE5i treatment in VO due to aorto-caval fistula (ACF) and to compare PDE5i treatment with standard heart failure (HF) therapy with angiotensin-converting enzyme inhibitor (ACEi). ACF/sham procedure was performed on male HanSD rats aged 8 weeks. ACF animals were randomized for PDE5i sildenafil, ACEi trandolapril, or placebo treatments. After 20 weeks, RV and LV function (echocardiography, pressure-volume analysis), myocardial gene expression, and renal function were studied. Separate rat cohorts served for survival analysis. ACF led to biventricular eccentric hypertrophy (LV: +68%, RV: +145%), increased stroke work (LV: 3.6-fold, RV: 6.7-fold), and reduced load-independent systolic function (PRSW, LV: -54%, RV: -51%). Both ACF ventricles exhibited upregulation of the genes of myocardial stress and glucose metabolism. ACEi but not PDE5i attenuated pulmonary congestion, LV remodeling, albuminuria, and improved survival (median survival in ACF/ACEi was 41 weeks vs. 35 weeks in ACF/placebo, p = .02). PDE5i increased cyclic guanosine monophosphate levels in the lungs, but not in the RV, LV, or kidney. PDE5i did not improve survival rate and cardiac and renal function in ACF rats, in contrast to ACEi. VO-induced HF is not responsive to PDE5i therapy.

• Keywords
• heart failure, phosphodiesterase-5 inhibition, rats, right ventricle, volume overload,
• MeSH
• Angiotensin-Converting Enzyme Inhibitors * pharmacology   MeSH
• Phosphodiesterase 5 Inhibitors * pharmacology   MeSH
• Cardiomegaly drug therapy   MeSH
• Rats MeSH
• Ventricular Remodeling * MeSH
• Heart Failure * drug therapy   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Angiotensin-Converting Enzyme Inhibitors * MeSH
• Phosphodiesterase 5 Inhibitors * MeSH

Background: A large arteriovenous fistula (AVF) is a low-resistant circuit that affects organ perfusion and systemic hemodynamics even in standard conditions. The extent of its' effect in critical states has not been elucidated yet. We used norepinephrine to create systemic vasoconstriction, dobutamine to create high cardiac output, and rapid right ventricle pacing as a model of acute heart failure in a porcine model of high-flow AVF circulation. Methods: The protocol was performed on nine domestic female pigs under general anesthesia. AVF was created by connecting two high-diameter ECMO cannulas inserted in the femoral artery and vein. Continuous hemodynamic monitoring was performed throughout the protocol. Three interventions were performed-moderate dose of norepinephrine (0.25 ug/kg/min), moderate dose of dobutamine (10 ug/kg/min) and rapid right ventricle pacing to simulate low cardiac output state with mean arterial pressure under 60 mmHg. Measurements were taken with opened and closed arteriovenous fistula. Results: Continuous infusion of norepinephrine with opened AVF significantly increased mean arterial pressure (+20%) and total cardiac output (CO) (+36%), but vascular resistance remained virtually unchanged. AVF flow (Qa) rise correlated with mean arterial pressure increase (+20%; R = 0.97, p = 0.0001). Effective cardiac output increased, leading to insignificant improvement in organ perfusion. Dobutamine substantially increased cardiac output with insignificant effect on AVF flow and mean arterial pressure. Carotid artery blood flow increased significantly after dobutamine infusion by approximately 30%, coronary flow velocity increased significantly only in closed AVF state. The effective cardiac output using the heart failure model leading to decrease of carotid artery flow and worsening of brain and peripheral tissue oximetry. AVF blood flow also dropped significantly and proportionally to pressure, but Qa/CO ratio did not change. Therefore, the effective cardiac output decreased. Conclusion: In abovementioned extreme hemodynamic conditions the AVF flow was always directly proportional to systemic perfusion pressure. The ratio of shunt flow to cardiac output depended on systemic vascular resistance. These experiments highlight the detrimental role of a large AVF in these critical conditions' models.

• Keywords
• arteriovenous fistula, dobutamine, hyperkinetic circulation, low cardiac output, norepinephrine,
• Publication type
• Journal Article MeSH

Chronic volume overload induces multiple cardiac remodeling processes that finally result in eccentric cardiac hypertrophy and heart failure. We have hypothesized that chronic angiotensin-converting enzyme (ACE) inhibition by trandolapril might affect various remodeling processes differentially, thus allowing their dissociation. Cardiac remodeling due to chronic volume overload and the effects of trandolapril were investigated in rats with an aortocaval fistula (ACF rats). The aortocaval shunt was created using a needle technique and progression of cardiac remodeling to heart failure was followed for 24 weeks. In ACF rats, pronounced eccentric cardiac hypertrophy and contractile and proarrhythmic electrical remodeling were associated with increased mortality. Trandolapril substantially reduced the electrical proarrhythmic remodeling and mortality, whereas the effect on cardiac hypertrophy was less pronounced and significant eccentric hypertrophy was preserved. Effective suppression of electrical proarrhythmic remodeling and mortality but not hypertrophy indicates that the beneficial therapeutic effects of ACE inhibitor trandolapril in volume overload heart failure might be dissociated from pure antihypertrophic effects.

• Keywords
• aortocaval fistula, cardiac remodeling, rat, renin-angiotensin-aldosterone system, trandolapril, volume overload,
• Publication type
• Journal Article MeSH

Mechanisms of right ventricular (RV) dysfunction in heart failure (HF) are poorly understood. RV response to volume overload (VO), a common contributing factor to HF, is rarely studied. The goal was to identify interventricular differences in response to chronic VO. Rats underwent aorto-caval fistula (ACF)/sham operation to induce VO. After 24 weeks, RV and left ventricular (LV) functions, gene expression and proteomics were studied. ACF led to biventricular dilatation, systolic dysfunction and hypertrophy affecting relatively more RV. Increased RV afterload contributed to larger RV stroke work increment compared to LV. Both ACF ventricles displayed upregulation of genes of myocardial stress and metabolism. Most proteins reacted to VO in a similar direction in both ventricles, yet the expression changes were more pronounced in RV (pslope: < 0.001). The most upregulated were extracellular matrix (POSTN, NRAP, TGM2, CKAP4), cell adhesion (NCAM, NRAP, XIRP2) and cytoskeletal proteins (FHL1, CSRP3) and enzymes of carbohydrate (PKM) or norepinephrine (MAOA) metabolism. Downregulated were MYH6 and FAO enzymes. Therefore, when exposed to identical VO, both ventricles display similar upregulation of stress and metabolic markers. Relatively larger response of ACF RV compared to the LV may be caused by concomitant pulmonary hypertension. No evidence supports RV chamber-specific regulation of protein expression in response to VO.

• MeSH
• Extracellular Matrix Proteins genetics   metabolism   MeSH
• Rats MeSH
• Cell Adhesion Molecules genetics   metabolism   MeSH
• Myocardium metabolism   MeSH
• Rats, Sprague-Dawley MeSH
• Protein Glutamine gamma Glutamyltransferase 2 MeSH
• Proteome genetics   metabolism   MeSH
• Pyruvate Kinase genetics   metabolism   MeSH
• Ventricular Remodeling * MeSH
• Heart Ventricles metabolism   pathology   physiopathology   MeSH
• Heart Failure metabolism   pathology   physiopathology   MeSH
• Stroke Volume MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Extracellular Matrix Proteins MeSH
• Cell Adhesion Molecules MeSH
• Pkm protein, rat MeSH Browser
• Protein Glutamine gamma Glutamyltransferase 2 MeSH
• Proteome MeSH
• Pyruvate Kinase MeSH
• Tgm2 protein, rat MeSH Browser

The detailed mechanisms determining the course of congestive heart failure (CHF) and associated renal dysfunction remain unclear. In a volume overload model of CHF induced by creation of aorto-caval fistula (ACF) in Hannover Sprague-Dawley (HanSD) rats we explored the putative pathogenetic contribution of epoxyeicosatrienoic acids (EETs), active products of CYP-450 dependent epoxygenase pathway of arachidonic acid metabolism, and compared it with the role of the renin-angiotensin system (RAS). Chronic treatment with cis-4-[4-(3-adamantan-1-yl-ureido) cyclohexyloxy]benzoic acid (c-AUCB, 3 mg/l in drinking water), an inhibitor of soluble epoxide hydrolase (sEH) which normally degrades EETs, increased intrarenal and myocardial EETs to levels observed in sham-operated HanSD rats, but did not improve the survival or renal function impairment. In contrast, chronic angiotensin-converting enzyme inhibition (ACEi, trandolapril, 6 mg/l in drinking water) increased renal blood flow, fractional sodium excretion and markedly improved survival, without affecting left ventricular structure and performance. Hence, renal dysfunction rather than cardiac remodeling determines long-term mortality in advanced stage of CHF due to volume overload. Strong protective actions of ACEi were associated with suppression of the vasoconstrictor/sodium retaining axis and activation of vasodilatory/natriuretic axis of the renin-angiotensin system in the circulating blood and kidney tissue.

• MeSH
• Angiotensin I blood   MeSH
• Angiotensin II blood   MeSH
• Benzoates pharmacology   therapeutic use   MeSH
• Epoxide Hydrolases antagonists & inhibitors   MeSH
• Epoxy Compounds metabolism   MeSH
• Angiotensin-Converting Enzyme Inhibitors MeSH
• Rats MeSH
• 8,11,14-Eicosatrienoic Acid analogs & derivatives   blood   metabolism   MeSH
• Kidney metabolism   MeSH
• Urea analogs & derivatives   pharmacology   therapeutic use   MeSH
• Disease Models, Animal MeSH
• Myocardium metabolism   MeSH
• Random Allocation MeSH
• Peptide Fragments blood   MeSH
• Drug Evaluation, Preclinical MeSH
• Renal Insufficiency blood   etiology   prevention & control   MeSH
• Renin-Angiotensin System drug effects   MeSH
• Heart Failure blood   complications   diagnostic imaging   drug therapy   MeSH
• Ultrasonography MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• 4-(4-(3-adamantan-1-ylureido)cyclohexyloxy)benzoic acid MeSH Browser
• angiotensin I (1-7) MeSH Browser
• Angiotensin I MeSH
• Angiotensin II MeSH
• Benzoates MeSH
• Epoxide Hydrolases MeSH
• Epoxy Compounds MeSH
• Angiotensin-Converting Enzyme Inhibitors MeSH
• 8,11,14-Eicosatrienoic Acid MeSH
• Urea MeSH
• Peptide Fragments MeSH