L-Carnitine prevents the development of ventricular fibrosis and heart failure with preserved ejection fraction in hypertensive heart disease

Mitochondrial Dysfunction in Heart Failure: From Pathophysiological Mechanisms to Therapeutic Opportunities

Mitochondrial dysfunction, a feature of heart failure, leads to a progressive decline in bioenergetic reserve capacity, consisting in a shift of energy production from mitochondrial fatty acid oxidation to glycolytic pathways. This adaptive process of cardiomyocytes does not represent an effective strategy to increase the energy supply and to restore the energy homeostasis in heart failure, thus contributing to a vicious circle and to disease progression. The increased oxidative stress causes cardiomyocyte apoptosis, dysregulation of calcium homeostasis, damage of proteins and lipids, leakage of mitochondrial DNA, and inflammatory responses, finally stimulating different signaling pathways which lead to cardiac remodeling and failure. Furthermore, the parallel neurohormonal dysregulation with angiotensin II, endothelin-1, and sympatho-adrenergic overactivation, which occurs in heart failure, stimulates ventricular cardiomyocyte hypertrophy and aggravates the cellular damage. In this review, we will discuss the pathophysiological mechanisms related to mitochondrial dysfunction, which are mainly dependent on increased oxidative stress and perturbation of the dynamics of membrane potential and are associated with heart failure development and progression. We will also provide an overview of the potential implication of mitochondria as an attractive therapeutic target in the management and recovery process in heart failure.

Myocardial Metabolism in Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is increasingly prevalent and now accounts for half of all heart failure cases. This rise is largely attributed to growing rates of obesity, hypertension, and diabetes. Despite its prevalence, the pathophysiological mechanisms of HFpEF are not fully understood. The heart, being the most energy-demanding organ, appears to have a compromised bioenergetic capacity in heart failure, affecting all phenotypes and aetiologies. While metabolic disturbances in heart failure with reduced ejection fraction (HFrEF) have been extensively studied, similar insights into HFpEF are limited. This review collates evidence from both animal and human studies, highlighting metabolic dysregulations associated with HFpEF and its risk factors, such as obesity, hypertension, and diabetes. We discuss how changes in substrate utilisation, oxidative phosphorylation, and energy transport contribute to HFpEF. By delving into these pathological shifts in myocardial energy production, we aim to reveal novel therapeutic opportunities. Potential strategies include modulating energy substrates, improving metabolic efficiency, and enhancing critical metabolic pathways. Understanding these aspects could be key to developing more effective treatments for HFpEF.

The Effects of L-Carnitine Supplementation on Blood Pressure in Adults: A Systematic Review and Dose-response Meta-analysis

PURPOSE

Hypertension stands as a prominent risk factor for cardiovascular disease, making it of utmost importance to address. Studies have shown that L-carnitine supplementation may lower blood pressure (BP) parameters in different populations. Therefore, we have conducted a systematic review and dose-response meta-analysis of published Randomized Controlled Trials (RCTs), including the most recent articles on the effect of L-carnitine supplementation on BP.

METHODS

PubMed, ISI Web of Science, Cochrane databases, and Scopus were used to collect RCT studies published up to October 2022 without limitations in language. Inclusion criteria were adult participants and recipients of L-carnitine in oral supplemental forms. The funnel plot test, Begg's test, and Egger's test were used to examine publication bias.

FINDINGS

After the search strategy, 22 RCTs (n = 1412) with 24 effect sizes fulfilled the criteria. It was found L-Carnitine supplementation did not have a significant effect on systolic blood pressure (SBP) (mm Hg) (weighted mean difference [WMD] = -1.22 mm Hg, 95% CI: -3.79, 1.35; P = 0.352; I2 = 85.0%, P < 0.001), and diastolic blood pressure (mm Hg) (WMD = -0.50 mm Hg, 95% CI: -1.49, 0.48; P = 0.318; I2 = 43.4%, P = 0.021) in the pooled analysis. Subgroup analyses have shown that L-carnitine supplementation had no lowering effect on SBP in any subgroup. However, there was a significant reduction in diastolic blood pressure in participants with a baseline body mass index >30 kg/m2 (WMD = -1.59 mm Hg; 95% CI: -3.11, -0.06; P = 0.041; I2 = 41.3%, P = 0.164). There was a significant nonlinear relationship between the duration of L-carnitine intervention and changes in SBP (coefficients = -6.83, P = 0.045).

IMPLICATIONS

L-carnitine supplementation in adults did not significantly affect BP. But anyway, more studies should be done in this field on different individuals.

Animal models of heart failure with preserved ejection fraction (HFpEF): from metabolic pathobiology to drug discovery

Heart failure (HF) with preserved ejection fraction (HFpEF) is currently a preeminent challenge for cardiovascular medicine. It has a poor prognosis, increasing mortality, and is escalating in prevalence worldwide. Despite accounting for over 50% of all HF patients, the mechanistic underpinnings driving HFpEF are poorly understood, thus impeding the discovery and development of mechanism-based therapies. HFpEF is a disease syndrome driven by diverse comorbidities, including hypertension, diabetes and obesity, pulmonary hypertension, aging, and atrial fibrillation. There is a lack of high-fidelity animal models that faithfully recapitulate the HFpEF phenotype, owing primarily to the disease heterogeneity, which has hampered our understanding of the complex pathophysiology of HFpEF. This review provides an updated overview of the currently available animal models of HFpEF and discusses their characteristics from the perspective of energy metabolism. Interventional strategies for efficiently utilizing energy substrates in preclinical HFpEF models are also discussed.

Targeting Mitochondrial Metabolism to Save the Failing Heart

Despite considerable progress in treating cardiac disorders, the prevalence of heart failure (HF) keeps growing, making it a global medical and economic burden. HF is characterized by profound metabolic remodeling, which mostly occurs in the mitochondria. Although it is well established that the failing heart is energy-deficient, the role of mitochondria in the pathophysiology of HF extends beyond the energetic aspects. Changes in substrate oxidation, tricarboxylic acid cycle and the respiratory chain have emerged as key players in regulating myocardial energy homeostasis, Ca²⁺ handling, oxidative stress and inflammation. This work aims to highlight metabolic alterations in the mitochondria and their far-reaching effects on the pathophysiology of HF. Based on this knowledge, we will also discuss potential metabolic approaches to improve cardiac function.

Clinical Phenotypes of Heart Failure With Preserved Ejection Fraction to Select Preclinical Animal Models

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To better define HFpEF clinically, patients are nowadays often clustered into phenogroups, based on their comorbidities and symptoms

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Many animal models claim to mimic HFpEF, but phenogroups are not yet regularly used to cluster them

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HFpEF animals models often lack reports of clinical symptoms of HF, therefore mainly presenting as extended models of LVDD, clinically seen as a prestate of HFpEF

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We investigated if clinically relevant phenogroups can guide selection of animal models aiming at better defined animal research

At least one-half of the growing heart failure population consists of heart failure with preserved ejection fraction (HFpEF). The limited therapeutic options, the complexity of the syndrome, and many related comorbidities emphasize the need for adequate experimental animal models to study the etiology of HFpEF, as well as its comorbidities and pathophysiological changes. The strengths and weaknesses of available animal models have been reviewed extensively with the general consensus that a “1-size-fits-all” model does not exist, because no uniform HFpEF patient exists. In fact, HFpEF patients have been categorized into HFpEF phenogroups based on comorbidities and symptoms. In this review, we therefore study which animal model is best suited to study the different phenogroups—to improve model selection and refinement of animal research. Based on the published data, we extrapolated human HFpEF phenogroups into 3 animal phenogroups (containing small and large animals) based on reports and definitions of the authors: animal models with high (cardiac) age (phenogroup aging); animal models focusing on hypertension and kidney dysfunction (phenogroup hypertension/kidney failure); and models with hypertension, obesity, and type 2 diabetes mellitus (phenogroup cardiometabolic syndrome). We subsequently evaluated characteristics of HFpEF, such as left ventricular diastolic dysfunction parameters, systemic inflammation, cardiac fibrosis, and sex-specificity in the different models. Finally, we scored these parameters concluded how to best apply these models. Based on our findings, we propose an easy-to-use classification for future animal research based on clinical phenogroups of interest.

Therapeutic Challenges and Emerging Treatment Targets for Pulmonary Hypertension in Left Heart Disease

Pulmonary hypertension (PH) attributable to left heart disease (LHD) is believed to be the most common form of PH and is strongly associated with increased mortality and morbidity in this patient population. Specific therapies for PH‐LHD have not yet been identified and the use of pulmonary artery hypertension‐targeted therapies in PH‐LHD are not recommended. Endothelin receptor antagonists, phosphodiesterase‐5 inhibitors, guanylate cyclase stimulators, and prostacyclins have all been studied in PH‐LHD with conflicting results. Understanding the mechanisms underlying PH‐LHD could potentially provide novel therapeutic targets. Fibrosis, oxidative stress, and metabolic syndrome have been proposed as pathophysiological components of PH‐LHD. Genetic associations have also been identified, offering additional mechanisms with biological plausibility. This review summarizes the evidence and challenges for treatment of PH‐LHD and focuses on underlying mechanisms on the horizon that could develop into potential therapeutic targets for this disease.

Carnitine promotes recovery from oxidative stress and extends lifespan in C. elegans

Carnitine is required for transporting fatty acids into the mitochondria for β-oxidation. Carnitine has been used as an energy supplement but the roles in improving health and delaying aging remain unclear. Here we show in C. elegans that L-carnitine improves recovery from oxidative stress and extends lifespan. L-carnitine promotes recovery from oxidative stress induced by paraquat or juglone and improves mobility and survival in response to H₂O₂ and human amyloid (Aβ) toxicity. L-carnitine also alleviates the oxidative stress during aging, resulting in moderate but significant lifespan extension, which was dependent on SKN-1 and DAF-16. Long-lived worms with germline loss (glp-1) or reduced insulin receptor activity (daf-2) recover from aging-associated oxidative stress faster than wild-type controls and their long lifespans were not further increased by L-carnitine. A new gene, T08B1.1, aligned to a known carnitine transporter OCTN1 in humans, is required for L-carnitine uptake in C. elegans. T08B1.1 expression is elevated in daf-2 and glp-1 mutants and its knockdown prevents L-carnitine from improving oxidative stress recovery and prolonging lifespan. Together, our study suggests an important role of L-carnitine in oxidative stress recovery that might be important for healthy aging in humans.

Metabolomic Profile in HFpEF vs HFrEF Patients

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF) are associated with metabolic derangements, which may have different pathophysiological implications.

METHODS AND RESULTS

In new-onset HFpEF (EF of ≥50%, n = 46) and HFrEF (EF of <40%, n = 75) patients, 109 endogenous plasma metabolites including amino acids, phospholipids and acylcarnitines were assessed using targeted metabolomics. Differentially altered metabolites and associations with clinical characteristics were explored. Patients with HFpEF were older, more often female with hypertension, atrial fibrillation, and diabetes compared with patients with HFrEF. Patients with HFpEF displayed higher levels of hydroxyproline and symmetric dimethyl arginine, alanine, cystine, and kynurenine reflecting fibrosis, inflammation and oxidative stress. Serine, cGMP, cAMP, l-carnitine, lysophophatidylcholine (18:2), lactate, and arginine were lower compared with patients with HFrEF. In patients with HFpEF with diabetes, kynurenine was higher (P = .014) and arginine lower (P = .014) vs patients with no diabetes, but did not differ with diabetes status in HFrEF. Decreasing kynurenine was associated with higher eGFR only in HFpEF (P_interaction = .020).

CONCLUSIONS

Patients with new-onset HFpEF compared with patients with new-onset HFrEF display a different metabolic profile associated with comorbidities, such as diabetes and kidney dysfunction. HFpEF is associated with indices of increased inflammation and oxidative stress, impaired lipid metabolism, increased collagen synthesis, and downregulated nitric oxide signaling. Together, these findings suggest a more predominant systemic microvascular endothelial dysfunction and inflammation linked to increased fibrosis in HFpEF compared with HFrEF.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT03671122 https://clinicaltrials.gov.

Treatment With Treprostinil and Metformin Normalizes Hyperglycemia and Improves Cardiac Function in Pulmonary Hypertension Associated With Heart Failure With Preserved Ejection Fraction

OBJECTIVE

Pulmonary hypertension (PH) due to left heart disease (group 2), especially in the setting of heart failure with preserved ejection fraction (HFpEF), is the most common cause of PH worldwide; however, at present, there is no proven effective therapy available for its treatment. PH-HFpEF is associated with insulin resistance and features of metabolic syndrome. The stable prostacyclin analog, treprostinil, is an effective and widely used Food and Drug Administration-approved drug for the treatment of pulmonary arterial hypertension. While the effect of treprostinil on metabolic syndrome is unknown, a recent study suggests that the prostacyclin analog beraprost can improve glucose intolerance and insulin sensitivity. We sought to evaluate the effectiveness of treprostinil in the treatment of metabolic syndrome-associated PH-HFpEF. Approach and Results: Treprostinil treatment was given to mice with mild metabolic syndrome-associated PH-HFpEF induced by high-fat diet and to SU5416/obese ZSF1 rats, a model created by the treatment of rats with a more profound metabolic syndrome due to double leptin receptor defect (obese ZSF1) with a vascular endothelial growth factor receptor blocker SU5416. In high-fat diet-exposed mice, chronic treatment with treprostinil reduced hyperglycemia and pulmonary hypertension. In SU5416/Obese ZSF1 rats, treprostinil improved hyperglycemia with similar efficacy to that of metformin (a first-line drug for type 2 diabetes mellitus); the glucose-lowering effect of treprostinil was further potentiated by the combined treatment with metformin. Early treatment with treprostinil in SU5416/Obese ZSF1 rats lowered pulmonary pressures, and a late treatment with treprostinil together with metformin improved pulmonary artery acceleration time to ejection time ratio and tricuspid annular plane systolic excursion with AMPK (AMP-activated protein kinase) activation in skeletal muscle and the right ventricle.

CONCLUSIONS

Our data suggest a potential use of treprostinil as an early treatment for mild metabolic syndrome-associated PH-HFpEF and that combined treatment with treprostinil and metformin may improve hyperglycemia and cardiac function in a more severe disease.

The Nutraceutical Value of Carnitine and Its Use in Dietary Supplements

Carnitine can be considered a conditionally essential nutrient for its importance in human physiology. This paper provides an updated picture of the main features of carnitine outlining its interest and possible use. Particular attention has been addressed to its beneficial properties, exploiting carnitine's properties and possible use by considering the main in vitro, in animal, and human studies. Moreover, the main aspects of carnitine-based dietary supplements have been indicated and defined with reference to their possible beneficial health properties.

Nutraceutical support in heart failure: a position paper of the International Lipid Expert Panel (ILEP)

Heart failure (HF) is a complex clinical syndrome that represents a major cause of morbidity and mortality in Western countries. Several nutraceuticals have shown interesting clinical results in HF prevention as well as in the treatment of the early stages of the disease, alone or in combination with pharmacological therapy. The aim of the present expert opinion position paper is to summarise the available clinical evidence on the role of phytochemicals in HF prevention and/or treatment that might be considered in those patients not treated optimally as well as in those with low therapy adherence. The level of evidence and the strength of recommendation of particular HF treatment options were weighed up and graded according to predefined scales. A systematic search strategy was developed to identify trials in PubMed (January 1970 to June 2019). The terms 'nutraceuticals', 'dietary supplements', 'herbal drug' and 'heart failure' or 'left verntricular dysfunction' were used in the literature search. The experts discussed and agreed on the recommendation levels. Available clinical trials reported that the intake of some nutraceuticals (hawthorn, coenzyme Q10, l-carnitine, d-ribose, carnosine, vitamin D, probiotics, n-3 PUFA and beet nitrates) might be associated with improvements in self-perceived quality of life and/or functional parameters such as left ventricular ejection fraction, stroke volume and cardiac output in HF patients, with minimal or no side effects. Those benefits tended to be greater in earlier HF stages. Available clinical evidence supports the usefulness of supplementation with some nutraceuticals to improve HF management in addition to evidence-based pharmacological therapy.

Sarcopenia in Cirrhosis: Looking Beyond the Skeletal Muscle Loss to See the Systemic Disease

Sarcopenia is a common complication of cirrhosis and is defined as a progressive and generalized loss of skeletal muscle mass, strength, and function. Sarcopenia is associated with poor prognosis and increased mortality. How sarcopenia and muscle wasting relate to such poor outcomes requires looking beyond the overt muscle loss and at this entity as a systemic disease that affects muscles of vital organs including cardiac and respiratory muscles. This review explores the pathophysiological pathways and mechanisms that culminate in poor outcomes associated with sarcopenia. This provides a launching pad to identify potential targets for therapeutic intervention and optimization to improve patient outcomes.

Exercise benefits in cardiovascular disease: beyond attenuation of traditional risk factors

Despite strong scientific evidence supporting the benefits of regular exercise for the prevention and management of cardiovascular disease (CVD), physical inactivity is highly prevalent worldwide. In addition to merely changing well-known risk factors for systemic CVD, regular exercise can also improve cardiovascular health through non-traditional mechanisms. Understanding the pathways through which exercise influences different physiological systems is important and might yield new therapeutic strategies to target pathophysiological mechanisms in CVD. This Review includes a critical discussion of how regular exercise can have antiatherogenic effects in the vasculature, improve autonomic balance (thereby reducing the risk of malignant arrhythmias), and induce cardioprotection against ischaemia-reperfusion injury, independent of effects on traditional CVD risk factors. This Review also describes how exercise promotes a healthy anti-inflammatory milieu (largely through the release of muscle-derived myokines), stimulates myocardial regeneration, and ameliorates age-related loss of muscle mass and strength, a frequently overlooked non-traditional CVD risk factor. Finally, we discuss how the benefits of exercise might also occur via promotion of a healthy gut microbiota. We argue, therefore, that a holistic view of all body systems is necessary and useful when analysing the role of exercise in cardiovascular health.

Maternal dietary calcium status during pregnancy and lactation affects brain DHA accretion through modifying DNA methylation of fatty acid desaturases in the mouse offspring

Disturbed calcium homeostasis has detrimental effects on brain development and function, particularly in early life because of epigenetic determination of early nutrition on later health. We hypothesized that the imbalance of calcium status in early life might have long-lasting effects on brain DHA accretion though epigenetic modification on fatty acid desaturases (Fads). Three to four week old C57BL/6J female mice were fed 3 reproductive diets with different calcium concentrations - low (LC, 0.25%), normal (NC, 0.70%) and high-calcium (HC, 1.20%) respectively throughout pregnancy and lactation. Maternal LC diet reduced tissue (brain and hepatic) DHA concentrations in both male and female offsprings at postnatal 21 day, with reductions in male instead of female offsprings in adulthood. Maternal HC diet only reduced hepatic DHA concentration in adult male offsprings. Furthermore, maternal LC diet reduced hepatic but increased brain expressions of Fads1 or Fads2 in 21-days old offsprings, with similar changes in adult male instead of female offsprings. Maternal HC diet reduced hepatic or brain expressions of Fads1 or Fads2 in 21-days old offsprings, and only reduced Fads2 in the liver with adult male offsprings. Determination of DNA methylation (CpG4, CpG5, CpG7,8, CpG14-17 and CpG19) showed that maternal LC diet caused hypermethylation of Fads2 promoter in the liver and hypomethylation in the brain in 21-days old offsprings, as well as in adult male offsprings. These data demonstrate that the imbalance of calcium intake in early life might have long-term gender-specific effects on brain accretion of DHA mediated by altered DNA methylation and associated expressions of Fads.

Trimetazidine and l‑carnitine prevent heart aging and cardiac metabolic impairment in rats via regulating cardiac metabolic substrates

BACKGROUND

This study aimed to investigate the effects of trimetazidine and l‑carnitine on heart aging and cardiac metabolism in the natural aging rats and explore the possible mechanism regarding the regulation of cardiac metabolic substrates.

METHODS

A total of 28 young (2-month-old) and 28 aged (14-month-old) male Sprague-Dawley rats were randomly allocated to the following groups: young control (YC, n = 8), young trimetazidine (YT, n = 10), young l‑carnitine (YL, n = 10), aging control (AC, n = 8), aging trimetazidine (AT, n = 10), and aging l‑carnitine (AL, n = 10). All rats were intragastrically treated with saline, trimetazidine, or l‑carnitine for 4 weeks. Blood sample parameters (MDA, SOD, Glu, TG, TC, LDL-c, HDL-c, AST, ALT, ALP, BUN, Cr, LDH), Echocardiographic paramerters, ATP levels of cardiac apex, cardiac pathology (HE staining and mitochondrial ultrastructures), and cardiac metabolism-related parameters (glucose transporter type-4[GLUT-4], carnitine palmitoyl transferase‑1[CPT-1]) were analyzed in each group.

RESULTS

The left ventricular ejection fractions were normal in most groups, with a higher value observed in the AT group than in the AC group. The AC group showed decreased ATP levels of cardiac apex compared with the YC group. But both trimetazidine and l‑carnitine attenuated the aging-induced decrease in ATP levels of cardiac apex. The AC group also showed increased myocardial fiber fragmentations and dissolutions, and interstitial proliferation compared with the YC group. However both trimetazidine and l‑carnitine protected against the aging-induced pathological changes in myocardium. Furthermore, both trimetazidine and l‑carnitine prevented mitochondria of cardiomyocytes from aging-induced injury. Both the AT and AL groups had significantly fewer focal cavitations and higher mitochondrial matrix electron densities than the AC group. GLUT-4 and CPT-1 protein levels were significantly lower while GLUT-4/CPT-1 ratios were higher in aging rats than YC rats. The AT and AL groups had significantly higher GLUT-4 and CPT-1 levels than the AC group, with more significant changes observed in the AT group.

CONCLUSIONS

Trimetazidine and l‑carnitine may partially improve the age-related changes of rat myocardial metabolisms and heart function via regulating cardiac metabolic substrates, with trimetazidine being superior. Interestingly, they may also reduce cardiac energy generation and impair mitochondrial structures in young rats. These findings suggest that age should be taken as an independent factor during the use of metabolic modulatory drugs in the patients with cardiovascular diseases because it may completely change the effects of drugs.

Effect of Levocarnitine on the Therapeutic Efficacy of Conventional Therapy in Children with Dilated Cardiomyopathy: Results of a Randomized Trial in 29 Children

BACKGROUND

The effect of levocarnitine supplementation has not been evaluated in children with dilated cardiomyopathy (DCM).

OBJECTIVE

The aim of this study was to explore the effect of oral levocarnitine supplementation in pediatric patients with DCM.

METHODS

Twenty-nine children with DCM (17 male, 12 female, aged 1 month to 13 years) were divided into two groups according to a simple randomization: control group (n = 10) and experimental group (n = 19). All children were given oral hydrochlorothiazide, enalapril, and spironolactone; additionally, patients with cardiac function of NYHA grade IV were given oral digoxin, and patients with intractable heart failure were given intravenous dopamine and dobutamine. When cardiac function was restored to NYHA grade II-III, patients were given oral metoprolol. Patients in the experimental group received add-on treatment with oral levocarnitine solution (50-100 mg/kg/day). Patients were followed up at 1, 3, 6 and 12 months. Left ventricular ejection fraction (EF), short axis shortening (FS), and left atrium (LA) and left ventricle (LV) diameters were measured at different times during the follow-up.

RESULTS

The children with DCM were followed up for 1 year. Cardiac function was significantly improved in the experimental group compared with the control group. Specifically, the EF and FS were increased (p < 0.05), the LA and LV diameters were reduced (p < 0.05), and the EF was increased more significantly in the experimental group than in the control group (p < 0.05).

CONCLUSIONS

Oral levocarnitine solution appeared to enhance the therapeutic efficacy of conventional therapy in children with DCM.

l-Carnitine and heart disease

Cardiovascular disease (CVD) is a key cause of deaths worldwide, comprising 15-17% of healthcare expenditure in developed countries. Current records estimate an annual global average of 30 million cardiac dysfunction cases, with a predicted escalation by two-three folds for the next 20-30years. Although β-blockers and angiotensin-converting-enzymes are commonly prescribed to control CVD risk, hepatotoxicity and hematological changes are frequent adverse events associated with these drugs. Search for alternatives identified endogenous cofactor l-carnitine, which is capable of promoting mitochondrial β-oxidation towards a balanced cardiac energy metabolism. l-Carnitine facilitates transport of long-chain fatty acids into the mitochondrial matrix, triggering cardioprotective effects through reduced oxidative stress, inflammation and necrosis of cardiac myocytes. Additionally, l-carnitine regulates calcium influx, endothelial integrity, intracellular enzyme release and membrane phospholipid content for sustained cellular homeostasis. Carnitine depletion, characterized by reduced expression of "organic cation transporter-2" gene, is a metabolic and autosomal recessive disorder that also frequently associates with CVD. Hence, exogenous carnitine administration through dietary and intravenous routes serves as a suitable protective strategy against ventricular dysfunction, ischemia-reperfusion injury, cardiac arrhythmia and toxic myocardial injury that prominently mark CVD. Additionally, carnitine reduces hypertension, hyperlipidemia, diabetic ketoacidosis, hyperglycemia, insulin-dependent diabetes mellitus, insulin resistance, obesity, etc. that enhance cardiovascular pathology. These favorable effects of l-carnitine have been evident in infants, juvenile, young, adult and aged patients of sudden and chronic heart failure as well. This review describes the mechanism of action, metabolism and pharmacokinetics of l-carnitine. It specifically emphasizes upon the beneficial role of l-carnitine in cardiomyopathy.

Murine Models of Heart Failure with Preserved Ejection Fraction: a "Fishing Expedition"

Heart failure with preserved ejection fraction (HFpEF) is characterized by signs and symptoms of HF in the presence of a normal left ventricular (LV) ejection fraction (EF). Despite accounting for up to 50% of all clinical presentations of HF, the mechanisms implicated in HFpEF are poorly understood, thus precluding effective therapy. The pathophysiological heterogeneity in the HFpEF phenotype also contributes to this disease and likely to the absence of evidence-based therapies. Limited access to human samples and imperfect animal models that completely recapitulate the human HFpEF phenotype have impeded our understanding of the mechanistic underpinnings that exist in this disease. Aging and comorbidities such as atrial fibrillation, hypertension, diabetes and obesity, pulmonary hypertension and renal dysfunction are highly associated with HFpEF. Yet, the relationship and contribution between them remains ill-defined. This review discusses some of the distinctive clinical features of HFpEF in association with these comorbidities and highlights the advantages and disadvantage of commonly used murine models, used to study the HFpEF phenotype.

Associations between acylcarnitine to free carnitine ratio and adverse prognosis in heart failure patients with reduced or preserved ejection fraction

Aims

The failing heart is accompanied by disturbed energy metabolism with mitochondrial dysfunction. Carnitine transports fatty acids into mitochondria for β‐oxidation. Decreased myocardial carnitine levels accompanied by increased plasma carnitine levels in heart failure (HF) have been reported. The plasma acylcarnitine to free carnitine ratio (AC/FC) is recognized as a marker of carnitine deficiency. We aimed to investigate the impact of the AC/FC on HF prognosis, taking into consideration differences between HF patients with preserved ejection fraction (HFpEF) and those with reduced ejection fraction (HFrEF).

Methods and results

Consecutive 168 HF patients were divided into three groups based on their AC/FC: first to third tertiles (n = 56, respectively). We followed up all patients for cardiac events including cardiac death and/or worsening HF. During the follow‐up period (1004 days), there were 23 cardiac deaths and 28 worsening HF. In the Kaplan–Meier analysis, the cardiac event rate of the third group was highest among the three groups (P = 0.022). In the Cox proportional hazard analysis, AC/FC was a predictor of cardiac events (P = 0.007). When HFpEF (n = 79) and HFrEF (n = 89) were analysed separately, the cardiac event rate of the third group was highest with regard to HFpEF (P = 0.008), but not HFrEF (P = 0.321). In the Cox proportional hazard analysis, AC/FC was a predictor of cardiac events with regard to HFpEF (P = 0.031), but not HFrEF (P = 0.095). Therefore, the impact of the AC/FC on cardiac events was different between HFpEF and HFrEF (P = 0.042 for interaction).

Conclusions

The AC/FC can identify high risk HF patients, especially in HFpEF.

Efficacy and Safety of L-Carnitine Treatment for Chronic Heart Failure: A Meta-Analysis of Randomized Controlled Trials

Background. Whether additional benefit can be achieved with the use of L-carnitine (L-C) in patients with chronic heart failure (CHF) remains controversial. We therefore performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the effects of L-C treatment in CHF patients. Methods. Pubmed, Ovid Embase, Web of Science, and Cochrane Library databases, Chinese National Knowledge Infrastructure (CNKI) database, Wanfang database, Chinese Biomedical (CBM) database, and Chinese Science and Technology Periodicals database (VIP) until September 30, 2016, were identified. Studies that met the inclusion criteria were systematically evaluated by two reviewers independently. Results. 17 RCTs with 1625 CHF patients were included in this analysis. L-C treatment in CHF was associated with considerable improvement in overall efficacy (OR = 3.47, P < 0.01), left ventricular ejection fraction (LVEF) (WMD: 4.14%, P = 0.01), strike volume (SV) (WMD: 8.21 ml, P = 0.01), cardiac output (CO) (WMD: 0.88 L/min, P < 0.01), and E/A (WMD: 0.23, P < 0.01). Moreover, treatment with L-C also resulted in significant decrease in serum levels of BNP (WMD: −124.60 pg/ml, P = 0.01), serum levels of NT-proBNP (WMD: −510.36 pg/ml, P < 0.01), LVESD (WMD: −4.06 mm, P < 0.01), LVEDD (WMD: −4.79 mm, P < 0.01), and LVESV (WMD: −20.16 ml, 95% CI: −35.65 to −4.67, P < 0.01). However, there were no significant differences in all-cause mortality, 6-minute walk, and adverse events between L-C and control groups. Conclusions. L-C treatment is effective for CHF patients in improving clinical symptoms and cardiac functions, decreasing serum levels of BNP and NT-proBNP. And it has a good tolerance.

The challenge of frailty and sarcopenia in heart failure with preserved ejection fraction

Frailty is a clinical state in which there is an increase in an individual's vulnerability for developing increased dependency and/or mortality when exposed to stressors. Frailty is often accompanied by heart failure with preserved ejection fraction (HFpEF), and frailty is likely to affect its clinical features and outcomes. Frail patients with HFpEF are frequently associated with sarcopenia (ie, muscle loss and weakness), which is a major component of the pathophysiology of frailty. Sarcopenia is a systemic skeletal muscle disease that impairs the function of limb skeletal muscles, as well as respiratory muscles, and this results in further functional decline. In addition, sarcopenia may contribute to cardiovascular remodelling and dysfunction, leading to the development of HFpEF through several metabolic and endocrine abnormalities. Although there is no established strategy for frail patients with HFpEF, a multidisciplinary approach, including various types of muscular training and nutritional intervention, may provide beneficial effects for these patients.

Immunohistochemical determination of the extracellular matrix modulation in a rat model of choline-deprived myocardium: the effects of carnitine

Choline has been identified as an essential nutrient with crucial role in many vital biological functions. Recent studies have demonstrated that heart dysfunction can develop in the setting of choline deprivation even in the absence of underlying heart disease. Matrix metalloproteinases (MMPs) are responsible for extracellular matrix degradation, and the dysregulation of MMP-2 and MMP-9 has been involved in the pathogenesis of various cardiovascular disorders. The aim of the study was to investigate the role of MMPs and their inhibitors (TIMPs), in the pathogenesis of choline deficiency-induced cardiomyopathy, and the way they are affected by carnitine supplementation. Male Wistar Albino adult rats were divided into four groups and received standard or choline-deficient diet with or without L-carnitine in drinking water (0.15% w/v) for 1 month. Heart tissue immunohistochemistry for MMP-2, MMP-9, TIMP-1, and TIMP-2 was performed. Choline deficiency was associated with suppressed immunohistochemical expression of MMP-2 and an increased expression of TIMP-2 compared to control, while it had no impact on TIMP-1. MMP-9 expression was decreased without, however, reaching statistical significance. Carnitine did not affect MMP-2, MMP-9, TIMP-1 or TIMP-2 expression. The pattern of TIMP and MMP modulation observed in a choline deficiency setting appears to promote fibrosis. Carnitine, although shown to suppress fibrosis, does not seem to affect MMP-2, MMP-9, TIMP-1 or TIMP-2 expression. Further studies will be required to identify the mechanism underlying the beneficial effects of carnitine.

Altered Metabolic Profile With Sodium-Restricted Dietary Approaches to Stop Hypertension Diet in Hypertensive Heart Failure With Preserved Ejection Fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is increasingly recognized as a distinct entity with unique pathophysiology. In the Dietary Approaches to Stop Hypertension in Diastolic Heart Failure (DASH-DHF) study, the sodium-restricted Dietary Approaches to Stop Hypertension diet (DASH/SRD) was associated with improved blood pressure and cardiovascular function in 13 hypertensive patients with HFpEF. With the use of targeted metabolomics, we explored metabolite changes and their relationship with energy-dependent measures of cardiac function in DASH-DHF.

METHODS AND RESULTS

With the use of chromatography and mass spectrometry, 152 metabolites including amino acids, free fatty acids, phospholipids, diglycerides, triglycerides, cholesterol esters, and acyl carnitines were measured. Comparison of baseline and post-DASH/SRD samples revealed increases in short-chain acetyl, butryl, and propionyl carnitines (P values .02, .03, .03, respectively). Increases in propionyl carnitine correlated with ventricular-arterial coupling ratio (Ees:Ea; r = 0.78; P = .005) and ventricular contractility (maximum rate of change of pressure-normalized stress [dσ*/dtmax]; r = 0.66; P = .03). Changes in L-carnitine also correlated with Ees:Ea (r = 0.62; P = .04) and dσ*/dtmax (r = 0.60; P = .05) and inversely with ventricular stiffness (r = -0.63; P = .03).

CONCLUSIONS

Metabolite profile changes of patients with HFpEF during dietary modification with the use of DASH/SRD suggest improved energy substrate utilization. Additional studies are needed to clarify connections between diet, metabolic changes, and myocardial function in HFpEF.

Levocarnitine Improves Cardiac Function in Hemodialysis Patients With Left Ventricular Hypertrophy: A Randomized Controlled Trial

BACKGROUND

Levocarnitine deficiency in hemodialysis patients is common. Although the effect of levocarnitine therapy on uremic anemia has been studied in small trials, its effects on cardiac function remain unclear.

STUDY DESIGN

Multicenter, prospective, open-label, parallel, randomized, controlled trial.

SETTING & PARTICIPANTS

Patients undergoing maintenance hemodialysis with carnitine deficiency (free carnitine plasma concentration < 40μmol/L) enrolled in 3 hemodialysis centers.

INTERVENTION

Random assignment to treatment for 12 months with oral levocarnitine therapy at a dose of 20mg/kg/d or control group (no levocarnitine therapy).

OUTCOMES & MEASUREMENTS

Cardiac function was assessed by echocardiography. The primary end point was change in ejection fraction from baseline at the end of the study. Secondary end points included changes in left ventricular mass index and clinical parameters from baseline at the end of the study.

RESULTS

222 patients were randomly assigned, of whom 148 patients (levocarnitine group, n=75; control group, n=73) were analyzed. Ejection fraction increased from baseline to the end of the study in the levocarnitine group by 5.43% (95% CI, 4.53%-6.32%), but not in the control group (change, -0.14%; between-group difference, 5.57% [95% CI, 4.48%-6.66%]; P<0.001). Left ventricular mass index decreased from baseline to the end of the study in the levocarnitine group (change of -8.89 [95% CI, -11.7 to -6.09] g/m(2)), but not in the control group (change of 1.62g/m(2); between-group difference, 10.50 [95% CI, 7.51 to 13.60] g/m(2); P<0.001). Levocarnitine therapy reduced N-terminal pro-brain natriuretic peptide (NT-proBNP) levels and improved the erythropoietin responsiveness index, whereas no such effects were observed in the control group.

LIMITATIONS

Not a double-blinded study.

CONCLUSIONS

Levocarnitine therapy is useful for hemodialysis patients with carnitine deficiency; these patients may benefit from such therapy, with amelioration of cardiac function and reduction of left ventricular mass index.

Excess Linoleic Acid Increases Collagen I/III Ratio and "Stiffens" the Heart Muscle Following High Fat Diets

Controversy exists on the benefits versus harms of n-6 polyunsaturated fatty acids (n-6 PUFA). Although n-6 PUFA demonstrates anti-atherosclerotic properties, survival following cardiac remodeling may be compromised. We hypothesized that n-6 PUFA like linoleic acid (LA) or other downstream PUFAs like γ-linolenic acid or arachidonic acid alter the transforming growth factor-β (TGFβ)-collagen axis in the heart. Excess dietary LA increased the collagen I/III ratio in the mouse myocardium, leading to cardiac "stiffening" characterized by impaired transmitral flow indicative of early diastolic dysfunction within 5 weeks. In vitro, LA under TGFβ1 stimulation increased collagen I and lysyl oxidase (LOX), the enzyme that cross-links soluble collagen resulting in deposited collagen. Overexpression of fatty acid desaturase 2 (fads2), which metabolizes LA to downstream PUFAs, reduced collagen deposits, LOX maturation, and activity with LA, whereas overexpressing fads1, unrelated to LA desaturation, did not. Furthermore, fads2 knockdown by RNAi elevated LOX activity and collagen deposits in fibroblasts with LA but not oleic acid, implying a buildup of LA for aggravating such pro-fibrotic effects. As direct incubation with γ-linolenic acid or arachidonic acid also attenuated collagen deposits and LOX activity, we concluded that LA itself, independent of other downstream PUFAs, promotes the pro-fibrotic effects of n-6 PUFA. Overall, these results attempt to reconcile opposing views of n-6 PUFA on the cardiovascular system and present evidence supporting a cardiac muscle-specific effect of n-6 PUFAs. Therefore, aggravation of the collagen I/III ratio and cardiac stiffening by excess n-6 PUFA represent a novel pathway of cardiac lipotoxicity caused by high n-6 PUFA diets.

Understanding different facets of cardiovascular diseases based on model systems to human studies: a proteomic and metabolomic perspective

Cardiovascular disease has remained as the largest cause of morbidity and mortality worldwide. From dissecting the disease aetiology to identifying prognostic markers for better management of the disease is still a challenge for researchers. In the post human genome sequencing era much of the thrust has been focussed towards application of advanced genomic tools along with evaluation of traditional risk factors. With the advancement of next generation proteomics and metabolomics approaches it has now become possible to understand the protein interaction network & metabolic rewiring which lead to the perturbations of the disease phenotype. Further, elucidating different post translational modifications using advanced mass spectrometry based methods have provided an impetus towards in depth understanding of the proteome. The past decade has observed a plethora of studies where proteomics has been applied successfully to identify potential prognostic and diagnostic markers as well as to understand the disease mechanisms for various types of cardiovascular diseases. In this review, we attempted to document relevant proteomics based studies that have been undertaken either to identify potential biomarkers or have elucidated newer mechanistic insights into understanding the patho-physiology of cardiovascular disease, primarily coronary artery disease, cardiomyopathy, and myocardial ischemia. We have also provided a perspective on the potential of proteomics in combating this deadly disease.

BIOLOGICAL SIGNIFICANCE

This review has catalogued recent studies on proteomics and metabolomics involved in understanding several cardiovascular diseases (CVDs). A holistic systems biology based approach, of which proteomics and metabolomics are two very important components, would help in delineating various pathways associated with complex disorders like CVD. This would ultimately provide better mechanistic understanding of the disease biology leading to development of prognostic biomarkers. This article is part of a Special Issue entitled: Proteomics in India.

Diagnosis and management of heart failure with preserved ejection fraction: 10 key lessons

Heart failure with preserved ejection fraction (HFpEF) is a common clinical syndrome associated with high rates of morbidity and mortality. Due to the lack of evidence-based therapies and increasing prevalence of HFpEF, clinicians are often confronted with these patients and yet have little guidance on how to effectively diagnose and manage them. Here we offer 10 key lessons to assist with the care of patients with HFpEF: (1) Know the difference between diastolic dysfunction, diastolic heart failure, and HFpEF; (2) diagnosing HFpEF is challenging, so be thorough and consider invasive hemodynamic testing to confirm the diagnosis; (3) a normal B-type natriuretic peptide does not exclude the diagnosis of HFpEF; (4) elevated pulmonary artery systolic pressure on echocardiography in the presence of a normal ejection fraction should prompt consideration of HFpEF; (5) use dynamic testing in evaluating the possibility of HFpEF in patients with unexplained dyspnea or exercise tolerance; (6) all patients with HFpEF should be systematically evaluated for the presence of coronary artery disease; (7) use targeted treatment for HFpEF patients based on their phenotypic classification; (8) treat HFpEF patients now by treating their comorbidities; (9) understand the importance of heart rate in HFpEF- lower is not always better; and (10) do not forget to consider rare diseases ("zebras") as causes for HFpEF when evaluating and treating patients. Taken together, these 10 key lessons can help clinicians care for challenging patients with HFpEF while we eagerly await the results of ongoing HFpEF clinical trials and observational studies.

Murine models of diastolic dysfunction and heart failure with preserved ejection fraction

Left ventricular diastolic dysfunction leads to heart failure with preserved ejection fraction, an increasingly prevalent condition largely driven by modern day lifestyle risk factors. As heart failure with preserved ejection fraction accounts for almost one-half of all patients with heart failure, appropriate nonhuman animal models are required to improve our understanding of the pathophysiology of this syndrome and to provide a platform for preclinical investigation of potential therapies. Hypertension, obesity, and diabetes are major risk factors for diastolic dysfunction and heart failure with preserved ejection fraction. This review focuses on murine models reflecting this disease continuum driven by the aforementioned common risk factors. We describe various models of diastolic dysfunction and highlight models of heart failure with preserved ejection fraction reported in the literature. Strengths and weaknesses of the different models are discussed to provide an aid to translational scientists when selecting an appropriate model. We also bring attention to the fact that heart failure with preserved ejection fraction is difficult to diagnose in animal models and that, therefore, there is a paucity of well described animal models of this increasingly important condition.

Heart failure with preserved ejection fraction: an ongoing enigma

Heart failure with preserved ejection fraction (HFpEF) is a complex clinical syndrome based on traditional heart failure symptoms with documentation of increased left ventricular filling pressures and preserved left ventricular ejection fraction. The exact mechanisms that induce HFpEF are not known. End-diastolic ventricular stiffness does not seem to be acting alone. Substantial mortality exists compared with healthy age-matched controls, as well as significant health care expenditures on hospitalizations and readmissions. This article reviews the epidemiology, pathophysiology, and treatment of heart failure with preserved ejection fraction (HFpEF). Current practice guidelines focus on remedying volume overload, aggressively controlling hypertension, and treatment of comorbid conditions that contribute to decompensation.

Urine L-carnitine excretion in hypertensive adolescents

Aim

This study was performed to test the hypothesis that urinary levels of l-carnitine and its derivatives are enhanced in children and adolescents with hypertension and also check if analyzed parameters may serve as early markers of subclinical renal damage.

Methods

The study included 112 children and adolescents (67 males and 45 females) aged median 10–18 years. Participants were divided into two groups: HT—64 subjects with confirmed primary hypertension and R—reference group—48 subjects with white-coat hypertension.

Urinary Free and Total l-carnitine were determined by the enzymatic method of Cederblad. The l-carnitine levels were expressed as urinary ratio in micromole per gram creatinine (μmol/g).

Results

The urinary excretion of Total and Free l-carnitine was significantly higher in hypertensive adolescents in comparison to reference group—white coat hypertension. Other important findings were positive correlations between Free l-carnitine/cr., Total l-carnitine/cr. ratio and serum uric acid level, serum cholesterol level and systolic blood pressure.

Conclusion

The results of this study do not explain the increased urine levels of l-carnitine. The most likely reason for excessive urinary loss was disturbed renal tubular reabsorption. It is possible to hypothesize that in hypertensive adolescents subclinical kidney dysfunction occurs. It is proposed that studies examining the concurrent plasma and urine concentration of l-carnitine and correlation with acknowledged proximal tubular markers are needed.

Primary Carnitine deficiency in the Faroe Islands: health and cardiac status in 76 adult patients diagnosed by screening

BACKGROUND

Carnitine deficiency can cause cardiomyopathy and cardiac arrhythmia. The prevalence in the Faroe Islands is the highest reported in the world (1:300). A nationwide screening program identified 76 Faroese adult patients (15-80 years) with Primary Carnitine Deficiency (PCD). We describe prior and current health status and symptoms in these patients, especially focusing on cardiac characteristics.

METHODS

Upon identification, patients were immediately admitted for physical examination, ECG, blood tests and initiation of L-carnitine supplementation. Medical records were reviewed and patients were interviewed. Echocardiography and blood tests were performed in 35 patients before and after L-carnitine supplementation.

RESULTS

All patients were either asymptomatic or had minor symptoms when diagnosed. Echocardiography including LVEF, global longitudinal strain and dimensions were normal apart from left ventricular hypertrophy with normal systolic function in one young male. Symptoms, e.g. fatigue, were reported in 43 % with a reduction to 12 % (p < 0.01) following initiation of L-carnitine supplementation. Eighty two % reported participation in sports of which 52 % were on a competitive level. ECGs showed limited changes and blood tests were normal. Mean plasma free carnitine increased from 6.1 μmol/L to 15.1 μmol/L (p < 0.01) within 50 days of L-carnitine supplementation.

CONCLUSION

PCD in adults can cause serious symptoms, but adult Faroese patients identified through a screening program were predominantly asymptomatic with a normal cardiac structure and function.

L-carnitine attenuates the development of kidney fibrosis in hypertensive rats by upregulating PPAR-γ

BACKGROUND

The development of renal fibrosis is a consequence of arterial hypertension. L-carnitine plays an essential role in the β-oxidation of fatty acids, and we have previously demonstrated hypotensive, antioxidant, and anti-inflammatory effects of L-carnitine in arterial hypertension. This work aims to analyze the effect of L-carnitine on renal fibrosis and to explore the participation of peroxisome-proliferator activated receptor (PPAR)-γ in this effect.

METHODS

Four groups or rats were used: control, treated with L-carnitine, treated with L-NAME, and treated with L-carnitine + L-NAME. Cultured rat kidney cells were also used to examine the role of PPAR-γ in L-carnitine effect.

RESULTS

An increase in the expression of collagen, transforming growth factor beta 1 (TGF-β1), connective tissue growth factor (CTGF), Nox2, and Nox4 was found in the kidney of L-NAME-treated rats. Hypertensive rats presented with an expansion of renal fibrotic areas, which was also accompanied by overexpression of proinflammatory cytokines, interleukin (IL)-1β, and IL-6. A reduction in the expression of PPAR-γ and in that of anti-inflammatory IL-10 was found in the kidney of these rats. Simultaneous treatment with L-carnitine attenuated the renal fibrosis (which correlated with a reduction of plasma TGF-β1 levels) and the pro-oxidative and proinflammatory status reported in L-NAME groups, with a concomitant increase in the expression of PPAR-γ. Furthermore, the antifibrotic effect of L-carnitine could be blocked by PPAR-γ inhibition.

CONCLUSIONS

This study confirms the efficacy of L-carnitine against hypertension-associated renal fibrosis from in vivo and in vitro studies and suggests that the L-carnitine effect occurs in a PPAR-γ-dependent manner.

Impact of sleep-disordered breathing on myocardial damage and metabolism in patients with chronic heart failure

Sleep-disordered breathing (SDB) has a critical association with mortality and morbidity of patients with chronic heart failure (CHF). Troponin T is a marker of ongoing myocardial damage and predicts adverse clinical outcomes in patients with CHF. Carnitine plays an important role in the utilization of fatty acids in the myocardium. It has been reported that myocardial carnitine levels decrease in the failing heart. We hypothesized that plasma troponin T and carnitine are increased due to the leakage from damaged cardiomyocytes or the alteration of myocardial metabolism in CHF patients with SDB. We examined the relation of plasma troponin T and carnitine levels with severity of SDB in CHF. We used portable sleep monitor and measured the apnea-hypopnea index (AHI), plasma levels of high-sensitive troponin T and carnitine in 131 CHF patients. These patients were divided into three groups based on AHI: group A (None-mild SDB AHI < 15/h, n = 45), group B (Moderate SDB 15 ≤ AHI < 30/h, n = 32) and group C (Severe SDB AHI ≥ 30/h, n = 54). Levels of high-sensitive troponin T and plasm total carnitine were significantly higher in group C than in groups A and B [high-sensitive troponin T; group A 0.009 (0.005-0.016), group B 0.012 (0.006-0.021), group C 0.021 (0.011-0.039) ng/ml, total carnitine; group A 61.0 ± 15.1, group B 65.0 ± 13.5, group C 73.3 ± 17.5 μmol/l, P < 0.01 vs. group A and P < 0.05 vs. group B, respectively]. Furthermore, in the multiple regression analysis, the independent factors to determine plasma levels of log (high-sensitive troponin T) were high-sensitive C-reactive protein and AHI, and the independent factors to determine plasma levels of carnitine were glomerular filtration rate and AHI. The present study suggests that SDB is associated with latent myocardial damage and alteration of myocardial carnitine metabolism in patients with CHF, presented by higher circulating troponin T and carnitine levels.

A novel heart failure mice model of hypertensive heart disease by angiotensin II infusion, nephrectomy, and salt loading

Although the mouse heart failure (HF) model of hypertensive heart disease (HHD) is useful to investigate the pathophysiology and new therapeutic targets for HHD, the model using simple experimental procedures and stable phenotypes has not been established. This study aimed to develop a novel mouse HF model of HHD by combining salt loading and uninephrectomy with ANG II infusion. Eight-week-old C57BL/6 male mice were treated with ANG II infusion (AT), ANG II infusion and uninephrectomy (AN), ANG II infusion and salt loading (AS), or ANG II infusion, uninephrectomy, and salt loading (ANS). Systolic blood pressure was significantly elevated and left ventricular (LV) hypertrophy was found in AT, AN, AS, and ANS mice, and there were no significant differences in those parameters between the four groups. At 6 wk after the procedures, only ANS mice showed significant decreases in LV fractional shortening and increases in lung weight with a high incidence. This phenotype was reproducible, and there were few perioperative or early deaths in the experimental procedures. Severe LV fibrosis was found in ANS mice. Oxidative stress was enhanced and small GTPase Rac1 activity was upregulated in the hearts of ANS mice. After the addition of salt loading and uninephrectomy to the ANG II infusion mouse model, cardiac function was significantly impaired, and mice developed HF. This might be a novel and useful mouse HF model to study the transition from compensated LV hypertrophy to HF in HHD.

Serum metabolomics reveals lipid metabolism variation between coronary artery disease and congestive heart failure: a pilot study

The aim of this pilot study is to find discriminating signals from the patient's congestive heart failure (HF) caused by coronary artery disease (CAD) through a non-target metabolomics method and test their usefulness in progress of human HF diseases. Multivariate data analysis was used to identify the discriminating signals. Interestingly, 12 metabolites contributing to the complete separation of HF from matched CAD were identified. Metabolic pathways including free fatty acids, sphingolipids and amino acid derivatives were found to be disturbed in HF patients compared with CAD patients. Lipid molecules associated with energy metabolism and signaling pathways may play key roles in the development of failing heart.

L-Carnitine protects against arterial hypertension-related cardiac fibrosis through modulation of PPAR-γ expression

Cardiac fibrosis is a pathogenic factor in a variety of cardiovascular diseases and is characterized by an abnormal accumulation of extracellular matrix protein that leads to cardiac dysfunction. l-Carnitine (LC) plays an essential role in the β-oxidation of long-chain fatty acids in lipid metabolism. We have previously demonstrated the beneficial effects of LC in hypertensive rats. The aim of this study was to analyze the effect of LC on arterial hypertension-associated cardiac fibrosis and to explore the mechanisms of LC action. To this end, four groups of rats were used: Wistar (control), rats treated with 400mg/kg/day of LC, rats treated with 25mg/kg/day of l-NAME (to induce hypertension), and rats treated with LC+l-NAME simultaneously. We found an elevation in the myocardial expression of profibrotic factors (TGF-β1 and CTGF), types I and III of collagen, and NADPH oxidase subunits (NOX2 and NOX4), in hypertensive rats when compared with normotensive ones. In addition, an increase in myocardial fibrosis was also found in the l-NAME group. These results were accompanied by a down-regulation of PPAR-γ in the heart of hypertensive animals. When hypertensive rats were treated with LC, all these alterations were reversed. Moreover, a significant negative correlation was observed between myocardial interstitial fibrosis and mRNA expression of PPAR-γ. In conclusion, the reduction of cardiac fibrosis and the down-regulation of NOX2, NOX4, TGF-β1 and CTGF induced by LC might be, at least in part, mediated by an upregulation of PPAR-γ, which leads to a reduction on hypertension-related cardiac fibrosis.