Impaired Myocardial Bioenergetics in HFpEF and the Role of Antioxidants

Left ventricular systolic function assessed by standard and advanced echocardiographic techniques in patients with systemic lupus erythematosus: A systemic review and meta-analysis

Objectives

Aim of the study was to perform a systemic review and meta-analysis of the current case-control studies based on the assessment of the left ventricular (LV) systolic function with standard and advanced echocardiographic methods.

Materials and methods

Objectives of the study, methods of statisticalanalysis, literature search strategy, inclusion andexclusion criteria, and outcome measurementswere defined according to Cochrane Collaborationsteps, 13 including recommendations for metaanalysisof observational studies in epidemiology (MOOSE).

Results

A total of 850 papers were collected. Of those, eight papers (10 groups) including 174,442 SLE patients and 45,608,723 controls with heart failure (HF), 20 papers including 1,121 SLE patients and 1,010 controls with an evaluated LV ejection fraction (LVEF), and eight studies (nine groups) including 462 SLE patients and 356 controls with a measured LV global longitudinal strain (LVGLS) met the predefined inclusion criteria. HF rate in SLE patients was 2.39% (4,176 of 174,442 patients with HF), and SLE patients showed a 3.4 times higher risk for HF compared to controls. SLE patients had a lower LVEF compared to controls. LVGLS was more impaired in SLE patients compared to controls, irrespective of two-dimensional or three-dimensional speckle tracking echocardiography.

Conclusion

Heart failure rate in SLE patients is high, and SLE patients showed a 3.4 times higher risk in patients with SLE compared to controls. LV systolic function, as measured by LVEF and LVGLS, is significantly affected in SLE patients, and LVGLS potentially represents a new tool for the early assessment of LV function.

Knockout of Trpa1 accelerates age-related cardiac fibrosis and dysfunction

Age-related cardiac fibrosis contributes to the development of heart failure with preserved ejection fraction which lacks ideal treatment. Transient receptor potential ankyrin 1 (TRPA1) is an oxidative stress sensor and could attenuate age-related pathologies in invertebrates. The present study aimed to test whether TRPA1 plays a role in age-related cardiac remodeling and dysfunction. The cardiac function and pathology of 12-week-old (young) and 52-week-old (older) Trpa1^-/- mice and wild-type (WT) littermates were evaluated by echocardiography and histologic analyses. The expression levels of 84 fibrosis-related genes in the heart were measured by quantitative polymerase chain reaction array. Young Trpa1^-/- and WT mice had similar left ventricular wall thickness, volume, and systolic and diastolic function. Older Trpa1^-/- mice had significantly increased left ventricular internal diameter and volume and impaired systolic (lower left ventricular ejection fraction) and diastolic (higher E/A ratio and isovolumetric relaxation time) functions compared with older WT mice (P<0.05 or P<0.01). Importantly, older Trpa1^-/- mice had enhanced cardiac fibrosis than older WT mice (P<0.05) while the two strains had similar degree of cardiac hypertrophy. Among the 84 fibrosis-related genes, Acta2, Inhbe, Ifng, and Ccl11 were significantly upregulated, while Timp3, Stat6, and Ilk were significantly downregulated in the heart of older Trpa1^-/- mice compared with older WT mice. Taken together, we found that knocking out Trpa1 accelerated age-related myocardial fibrosis, ventricular dilation, and cardiac dysfunction. These findings suggest that TRPA1 may become a therapeutic target for preventing and/or treating cardiac fibrosis and heart failure with preserved ejection fraction in the elderly.

Prognosticators of All-Cause Mortality in Patients With Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) represents ∼50% of all cases of congestive heart failure (CHF) with prevalence expected to increase with aging of the population. We performed an observational study of all patients admitted to 3 hospitals in the ExcelaHealth care system, Greensburg, PA, with a primary diagnosis of HFpEF heart failure exacerbation between January 2014 and January 2017. Demographic data, laboratory results, and echocardiograms performed closest to index hospitalization were collected. A total of 487 patients were admitted with a primary diagnosis of CHF exacerbation and HFpEF, with a mean age of 80.5 years (±10.9), 62% women and predominantly Caucasian (98.8%). Over a median follow-up of 21.7 months, 246 patients died with an all-cause mortality rate of 51.3%. Receiver operator curves were generated for multiple continuous variables to identify optimal cut-off values Kaplan-Meir survival curves were then generated. Clinical factors were tested by univariate Cox regression modeling, with significant factors entered into a step-wise multivariate model. Our modeling identified age>80 years, serum albumin level<3.2 g/dl, N-terminal pro-brain natriuretic peptide (NT-proBNP) >5,000 pg/mL and medial E/e'≥20 as significant, independent predictors of all-cause mortality (p-value <0.0001). Surprisingly, lack of a diagnosis of hypertension was associated with significantly increased mortality risk. In a community-based sample of HFpEF patients, we identified multiple factors that were strong, independent predictors of all-cause mortality that can be easily applied in a clinical setting.

A SIRT1 Activator, Ginsenoside Rc, Promotes Energy Metabolism in Cardiomyocytes and Neurons

Targeting SIRT1 signaling pathway could improve glucose aerobic metabolism and mitochondrial biosynthesis to resist cardiac and neurological injuries. Ginsenoside Rc has been identified for targeting mitochondrial function, but how ginsenoside Rc interacts with SIRT1 to regulate energy metabolism in cardiomyocytes and neurons under physiological or ischemia/reperfusion (I/R)-injured conditions has not been clearly investigated. Here, we confirm the interaction of Rc on the residue sites of SIRT1 in promoting its activity. Ginsenoside Rc significantly promotes mitochondrial biogenesis and increases the levels of electron-transport chain complex II-IV in cardiomyocytes and neurons. Meanwhile, ginsenoside Rc pretreatment increases ATP production, glucose uptake, and the levels of hexokinase I/II and mitochondrial pyruvate carrier I/II in both cell models. In addition, ginsenoside Rc activates the PGC1α pathway to induce mitochondrial biosynthesis. More importantly, ginsenoside Rc reduces mitochondrial damage and apoptosis through SIRT1 restoration-mediated reduction of PGC1α acetylation in the I/R-induced cardiac and neuronal models. Collectively, the in vitro and in vivo data indicate that ginsenoside Rc as a SIRT1 activator promotes energy metabolism to improve cardio- and neuroprotective functions under normal and I/R injury conditions, which provides new insights into the molecular mechanism of ginsenoside Rc as a protective agent.

Mechanisms underlying the pathophysiology of heart failure with preserved ejection fraction: the tip of the iceberg

Heart failure with preserved ejection fraction (HFpEF) is a multifaceted syndrome with a complex aetiology often associated with several comorbidities, such as left ventricle pressure overload, diabetes mellitus, obesity, and kidney disease. Its pathophysiology remains obscure mainly due to the complex phenotype induced by all these associated comorbidities and to the scarcity of animal models that adequately mimic HFpEF. Increased oxidative stress, inflammation, and endothelial dysfunction are currently accepted as key players in HFpEF pathophysiology. However, we have just started to unveil HFpEF complexity and the role of calcium handling, energetic metabolism, and mitochondrial function remain to clarify. Indeed, the enlightenment of such cellular and molecular mechanisms represents an opportunity to develop novel therapeutic approaches and thus to improve HFpEF treatment options. In the last decades, the number of research groups dedicated to studying HFpEF has increased, denoting the importance and the magnitude achieved by this syndrome. In the current technological and web world, the amount of information is overwhelming, driving us not only to compile the most relevant information about the theme but also to explore beyond the tip of the iceberg. Thus, this review aims to encompass the most recent knowledge related to HFpEF or HFpEF-associated comorbidities, focusing mainly on myocardial metabolism, oxidative stress, and energetic pathways.

Mitochondrial Reversible Changes Determine Diastolic Function Adaptations During Myocardial (Reverse) Remodeling

BACKGROUND

Often, pressure overload-induced myocardial remodeling does not undergo complete reverse remodeling after decreasing afterload. Recently, mitochondrial abnormalities and oxidative stress have been successively implicated in the pathogenesis of several chronic pressure overload cardiac diseases. Therefore, we aim to clarify the myocardial energetic dysregulation in (reverse) remodeling, mainly focusing on the mitochondria.

METHODS

Thirty-five Wistar Han male rats randomly underwent sham or ascending (supravalvular) aortic banding procedure. Echocardiography revealed that banding induced concentric hypertrophy and diastolic dysfunction (early diastolic transmitral flow velocity to peak early-diastolic annular velocity ratio, E/E': sham, 13.6±2.1, banding, 18.5±4.1, P=0.014) accompanied by increased oxidative stress (dihydroethidium fluorescence: sham, 1.6×10⁸±6.1×10⁷, banding, 2.6×10⁸±4.5×10⁷, P<0.001) and augmented mitochondrial function. After 8 to 9 weeks, half of the banding animals underwent overload relief by an aortic debanding surgery (n=10).

RESULTS

Two weeks later, hypertrophy decreased with the decline of oxidative stress (dihydroethidium fluorescence: banding, 2.6×10⁸±4.5×10⁷, debanding, 1.96×10⁸±6.8×10⁷, P<0.001) and diastolic dysfunction improved simultaneously (E/E': banding, 18.5±4.1, debanding, 15.1±1.8, P=0.029). The reduction of energetic demands imposed by overload relief allowed the mitochondria to reduce its activity and myocardial levels of phosphocreatine, phosphocreatine/ATP, and ATP/ADP to normalize in debanding towards sham values (phosphocreatine: sham, 38.4±7.4, debanding, 35.6±8.7, P=0.71; phosphocreatine/ATP: sham, 1.22±0.23 debanding, 1.11±0.24, P=0.59; ATP/ADP: sham, 6.2±0.9, debanding, 5.6±1.6, P=0.66). Despite the decreased mitochondrial area, complex III and V expression increased in debanding compared with sham or banding. Autophagy and mitophagy-related markers increased in banding and remained higher in debanding rats.

CONCLUSIONS

During compensatory and maladaptive hypertrophy, mitochondria become more active. However, as the disease progresses, the myocardial energetic demands increase and the myocardium becomes energy deficient. During reverse remodeling, the concomitant attenuation of cardiac hypertrophy and oxidative stress allowed myocardial energetics, left ventricle hypertrophy, and diastolic dysfunction to recover. Autophagy and mitophagy are probably involved in the myocardial adaptation to overload and to unload. We conclude that these mitochondrial reversible changes underlie diastolic function adaptations during myocardial (reverse) remodeling.

Potential use of ubiquinol and d-ribose in patients with heart failure with preserved ejection fraction

•Manuscript Highlights.•HFpEF is associated with reduced ATP production in the myocardium.•Ubiquinol and d-ribose both contribute to the generation of myocardial ATP.•Both ubiquinol and d-ribose are being studied as supplemental treatments for patients with HFpEF.

Cooperative Effects of Q10, Vitamin D3, and L-Arginine on Cardiac and Endothelial Cells

This work demonstrates the cooperative effect of Q10, vitamin D3, and L-arginine on both cardiac and endothelial cells. The effects of Q10, L-arginine, and vitamin D3 alone or combined on cell viability, nitric oxide, and reactive oxygen species productions in endothelial and cardiac cells were studied. Moreover, the involvement of PI3K/Akt and ERK/MAPK pathways leading to eNOS activation as well as the involvement of vitamin D receptor were also investigated. The same agents were tested in an animal model to verify vasodilation, nitric oxide, and reactive oxygen species production. The data obtained in this work demonstrate for the first time the beneficial and cooperative effect of stimulation with Q10, L-arginine, and vitamin D3. Indeed, in cardiac and endothelial cells, Q10, L-arginine, and vitamin D3 combined were able to induce a nitric oxide production higher than the that induced by the 3 substances alone. The effects on vasodilation induced by cooperative stimulation have been confirmed in an in vivo model as well. The use of a combination of Q10, L-arginine, and vitamin D to counteract increased free radical production could be a potential method to reduce myocardial injury or the effects of aging on the heart.