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The myocardial contractile response to physiological stress improves with high saturated fat feeding in heart failure.

ABSTRACT: Impaired myocardial contractile function is a hallmark of heart failure (HF), which may present under resting conditions and/or during physiological stress. Previous studies have reported that high fat feeding in mild to moderate HF/left ventricular (LV) dysfunction is associated with improved contractile function at baseline. The goal of this study was to determine whether myocardial function is compromised in response to physiological stress and to evaluate the global gene expression profile of rats fed high dietary fat after infarction. Male Wistar rats underwent ligation or sham surgery and were fed normal chow (NC; 10% kcal fat; Sham + NC and HF + NC groups) or high-fat chow (SAT; 60% kcal saturated fat; Sham + SAT and HF + SAT groups) for 8 wk. Myocardial contractile function was assessed using a Millar pressure-volume conductance catheter at baseline and during inferior vena caval occlusions and dobutamine stress. Steady-state indexes of systolic function, LV +dP/dt(max), stroke work, and maximal power were increased in the HF + SAT group versus the HF + NC group and reduced in the HF + NC group versus the Sham + NC group. Preload recruitable measures of contractility were decreased in HF + NC group but not in the HF + SAT group. beta-Adrenergic responsiveness [change in LV +dP/dt(max) and change in cardiac output with dobutamine (0-10 microg x kg(-1) x min(-1))] was reduced in HF, but high fat feeding did not further impact the contractile reserve in HF. The contractile reserve was reduced by the high-fat diet in the Sham + SAT group. Microarray gene expression analysis revealed that the majority of significantly altered pathways identified contained multiple gene targets correspond to cell signaling pathways and energy metabolism. These findings suggest that high saturated fat improves myocardial function at rest and during physiological stress in infarcted hearts but may negatively impact the contractile reserve under nonpathological conditions. Furthermore, high fat feeding-induced alterations in gene expression related to energy metabolism and specific signaling pathways revealed promising targets through which high saturated fat potentially mediates cardioprotection in mild to moderate HF/LV dysfunction.

SUBMITTER: Berthiaume JM

PROVIDER: S-EPMC2930388 | biostudies-literature | 2010 Aug

REPOSITORIES: biostudies-literature

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The myocardial contractile response to physiological stress improves with high saturated fat feeding in heart failure.

Berthiaume Jessica M JM Bray Molly S MS McElfresh Tracy A TA Chen Xiaoqin X Azam Salman S Young Martin E ME Hoit Brian D BD Chandler Margaret P MP

American journal of physiology. Heart and circulatory physiology 20100528 2

Impaired myocardial contractile function is a hallmark of heart failure (HF), which may present under resting conditions and/or during physiological stress. Previous studies have reported that high fat feeding in mild to moderate HF/left ventricular (LV) dysfunction is associated with improved contractile function at baseline. The goal of this study was to determine whether myocardial function is compromised in response to physiological stress and to evaluate the global gene expression profile o ...[more]

PMID: 20511406

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Project description:Impaired myocardial contractile function is a hallmark of heart failure (HF) which may present under resting conditions and/or during physiological stress. Previous studies reported that high fat feeding in HF is associated with improved myocardial contractile function at baseline. Our goal was to determine whether myocardial function is compromised in response to physiological stress and to evaluate the global gene expression profile of rats fed high dietary fat following infarction. Male Wistar rats underwent ligation or sham surgery and were fed normal (10% kcal fat) (SHAM+NC, HF+NC) or high fat (60% kcal saturated fat) (SHAM+SAT, HF+SAT) for 8 weeks. Myocardial contractile function was assessed using a Millar pressure-volume (PV) conductance catheter at baseline, during inferior vena caval occlusions and dobutamine (DOB) stress. Steady state indices of systolic function, left ventricular (LV)+dP/dtmax, stroke work and maximal power were increased in HF+SAT vs HF+NC; HF+NC were reduced vs SHAM+NC. Preload-recruitable measures of contractility [end systolic PV relationship, maximal elastance, preload recruitable SW and peak+dP/dtmax to end diastolic volume] were decreased in HF+NC but not HF+SAT. β-adrenergic responsiveness (delta-LV+dP/dtmax and delta-cardiac output DOB 0-10 µg•kg-1•min-1) was reduced in HF, but high fat feeding did not further impact contractile reserve in HF. Contractile reserve was reduced by high fat in SHAM+SAT. Microarray gene expression analysis reveals the majority of significantly altered pathways identified to contain multiple gene targets correspond to cell signaling pathways and energy metabolism. These findings suggest that high saturated fat improves myocardial function at rest and during physiological stress in infarcted hearts, but may negatively impact contractile reserve under non-pathological conditions. Furthermore, high fat feeding-induced alterations in gene expression related to energy metabolism and specific signaling pathways reveal promising targets through which high saturated fat potentially mediates cardioprotection in heart failure/LV dysfunction. Comparison of gene expression in heart failure or sham surgery hearts exposed to saturated or normal diets. Male Wistar rats (300-350g) were maintained on a reverse light-dark cycle and all procedures were done 3-6 hours into the dark phase cycle to synchronize with the normal active state of the rodents. Rats were randomly assigned to receive either a sham-operation (SH) or coronary ligation to induce cardiac dysfunction (HF). Heart failure was induced by ligating the left main coronary artery. Following surgery, rats were immediately fed either a normal rodent chow (NC) or a high saturated fat chow (SAT) with 60% caloric content derived from fat (25% palmitic, 33% stearic, 33% oleic acid, Research Diets).

Project description:AimsThe diagnostic and treatment of patients with heart failure with preserved ejection fraction (HFpEF) are both hampered by an incomplete understanding of the pathophysiology of the disease. Novel imaging tools to adequately identify these patients from individuals with a normal cardiac function and respectively patients with HF with reduced EF are warranted. Computing multilayer myocardial strain with feature tracking is a fast and accurate method to assess cardiac deformation. Our purpose was to assess the HFpEF diagnostic ability of multilayer strain parameters and compare their sensitivity and specificity with other established parameters.Methods and resultsWe included 20 patients with a diagnosis of HFpEF and, respectively, 20 matched controls. We assessed using feature-tracking cardiac magnetic resonance longitudinal and circumferential myocardial strain at three distinct layers of the myocardium: subendocardial (Endo-), mid-myocardial (Myo-), and subepicardial (Epi-). Comparatively, we additionally assessed various others clinical, imaging, and biochemical parameters with a putative role in HFpEF diagnostic: left ventricular end-diastolic volume (LVEDV), left ventricular mass (LVM), interventricular septum (IVS) wall thickness and free wall thickness, left atrial volume and strain, septal and lateral mitral annular early diastolic velocity (e`), E/e´ ratio, and plasma levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP). Global longitudinal strain (GLS) is significantly impaired at Endo (-20.8 ± 4.0 vs. -23.2 ± 3.4, P = 0.046), Myo- (-18.0 ± 3.0 vs. -21.0 ± 2.5, P = 0.002), and Epi- (-12.2 ± 2.0 vs. -16.2 ± 2.5, P < 0.001) levels. Compared with any other imaging parameter, an Epi-GLS lower than 13% shows the highest ability to detect patients with HFpEF [area under the curve (AUC) = 0.90 (0.81-1), P < 0.001] and in tandem with NT-proBNP can diagnose with maximal sensibility (93%) and specificity (100%), patients with HFpEF from normal, composed variable [AUC = 0.98 (0.95-1), P < 0.001]. In a logistic regression model, a composite predictive variable taking into account both GLS Epi and NT-proBNP values in each individual subject reached a sensitivity of 89% and a specificity of 100% with an AUC of 0.98 (0.95-1), P < 0.001, to detect HFpEF.ConclusionsEpi-GLS is a promising new imaging parameter to be considered in the clinical assessment of HFpEF patients. Given its excellent specificity, in tandem with a highly sensitive parameter such as NT-proBNP, Epi-GLS holds the potential to greatly improve the current diagnostic algorithms.

Project description:Background and purposeWhile maintaining cardiac performance, chronic ?-adrenoceptor activation eventually exacerbates the progression of cardiac remodelling and failure. We examined the adverse signalling pathways mediated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and reactive oxygen species (ROS) after chronic ??-adrenoceptor activation.Experimental approachMice with transgenic ??-adrenoceptor overexpression (??-TG) and non-transgenic littermates were either untreated or treated with an antioxidant (N-acetylcysteine, NAC) or NADPH oxidase inhibitors (apocynin, diphenyliodonium). Levels of ROS, phosphorylated p38 mitogen-activated protein kinase (MAPK), pro-inflammatory cytokines and collagen content in the left ventricle (LV) and LV function were measured and compared.Key results??-TG mice showed increased ROS production, phosphorylation of p38 MAPK and heat shock protein 27 (HSP27), expression of pro-inflammatory cytokines and collagen, and progressive ventricular dysfunction. ??-adrenoceptor stimulation similarly increased ROS production and phosphorylation of p38 MAPK and HSP27 in cultured cardiomyocytes. Treatment with apocynin, diphenyliodonium or NAC reduced phosphorylation of p38 MAPK and HSP27 in both cultured cardiomyocytes and the LV of ??-TG mice. NAC treatment (500 mg·kg?¹ ·day?¹) for 2 weeks eliminated the up-regulated expression of pro-inflammatory cytokines and collagen in the LV of ??-TG mice. Chronic NAC treatment to ??-TG mice from 7 to 10 months of age largely prevented progression of ventricular dilatation, preserved contractile function (fractional shortening 37 ± 5% vs. 25 ± 3%, ejection fraction 52 ± 5% vs. 32 ± 4%, both P < 0.05), reduced cardiac fibrosis and suppressed matrix metalloproteinase activity.Conclusion and implications??-adrenoceptor stimulation provoked NADPH oxidase-derived ROS production in the heart. Elevated ROS activated p38 MAPK and contributed significantly to cardiac inflammation, remodelling and failure.

Project description:Metabolic syndrome is a cluster of obesity-related metabolic abnormalities that lead to metabolic heart disease (MHD) with left ventricular pump dysfunction. Although MHD is thought to be associated with myocardial energetic deficiency, two key questions have not been answered. First, it is not known whether there is a sufficient energy deficit to contribute to pump dysfunction. Second, the basis for the energy deficit is not clear. To address these questions, mice were fed a high fat, high sucrose (HFHS) 'Western' diet to recapitulate the MHD phenotype. In isolated beating hearts, we used 31P NMR spectroscopy with magnetization transfer to determine a) the concentrations of high energy phosphates ([ATP], [ADP], [PCr]), b) the free energy of ATP hydrolysis (∆G~ATP), c) the rate of ATP production and d) flux through the creatine kinase (CK) reaction. At the lowest workload, the diastolic pressure-volume relationship was shifted upward in HFHS hearts, indicative of diastolic dysfunction, whereas systolic function was preserved. At this workload, the rate of ATP synthesis was decreased in HFHS hearts, and was associated with decreases in both [PCr] and ∆G~ATP. Higher work demands unmasked the inability of HFHS hearts to increase systolic function and led to a further decrease in ∆G~ATP to a level that is not sufficient to maintain normal function of sarcoplasmic Ca2+-ATPase (SERCA). While [ATP] was preserved at all work demands in HFHS hearts, the progressive increase in [ADP] led to a decrease in ∆G~ATP with increased work demands. Surprisingly, CK flux, CK activity and total creatine were normal in HFHS hearts. These findings differ from dilated cardiomyopathy, in which the energetic deficiency is associated with decreases in CK flux, CK activity and total creatine. Thus, in HFHS-fed mice with MHD there is a distinct metabolic phenotype of the heart characterized by a decrease in ATP production that leads to a functionally-important energetic deficiency and an elevation of [ADP], with preservation of CK flux.

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The myocardial contractile response to physiological stress improves with high saturated fat feeding in heart failure.

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The myocardial contractile response to physiological stress improves with high saturated fat feeding in heart failure.

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