Apoptosis in the failing human heart

MicroRNA-328 is involved in the effect of selenium on hydrogen peroxide-induced injury in H9c2 cells

Oxidative stress induces apoptosis in cardiac cells, and antioxidants attenuate the injury. MicroRNAs (miRNAs) are also involved in cell death; therefore, this study aimed to investigate the role of miRNAs in the effect of selenium on oxidative stress-induced apoptosis. The effects of sodium selenite were analyzed via cell viability, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) concentration. Flow cytometry was used to evaluate cell apoptosis. Fura-2AM was used to calculate intracellular Ca²⁺ concentration. Sodium selenite could ameliorate hydrogen peroxide (H₂ O₂ )-induced cell apoptosis and improve expression levels of glutathione peroxidase and thioredoxin reductase. Pretreatment with sodium selenite improved SOD activity and reduced MDA concentration. Treatments with H₂ O₂ or sodium selenite decreased miR-328 levels. MiR-328 overexpression enhanced cell apoptosis, reduced ATP2A2 levels, and increased intracellular Ca²⁺ concentration, while inhibition produced opposite effects. MiR-328 might be involved in the effect of sodium selenite on H₂ O₂ -induced cell death in H9c2 cells.

Role of the calcium sensing receptor in cardiomyocyte apoptosis via mitochondrial dynamics in compensatory hypertrophied myocardium of spontaneously hypertensive rat

Calcium sensing receptor (CaSR) mediates pathological cardiac hypertrophy. Mitochondria maintain their function through fission and fusion and disruption of mitochondrial dynamic is linked to various cardiac diseases. This study examined how inhibition of CaSR by the inhibitor Calhex₂₃₁ affected the mitochondrial dynamics in a hypertensive model in rats. Spontaneously hypertensive rats (SHRs) and Wistar Kyoto (WKY) rats were used in this study. Cardiac function and blood pressure was evaluated at the end of the study. SHRs showed increases in the ratio of heart weight to body weight and the levels of CaSR; all of these increases were suppressed by Calhex₂₃₁. Additionally, Calhex₂₃₁ treatment of SHRs changed the expression of proteins involved in mitochondrial dynamics. Our results demonstrated that CaSR activation induced cardiomyocyte apoptosis through the mitochondrial dynamics mediated apoptotic pathway in hypertensive hearts.

MicroRNA-15a inhibition protects against hypoxia/reoxygenation-induced apoptosis of cardiomyocytes by targeting mothers against decapentaplegic homolog 7

Myocardial ischemia/reperfusion (I/R) injury is a major pathological process in coronary heart disease and cardiac surgery, and is associated with aberrant microRNA (miR) expression. Previous studies have demonstrated that inhibition of miR-15a expression may ameliorate I/R-induced myocardial injury. In the present study, the potential role and underlying mechanism of miR-15a in hypoxia/reoxygenation-induced apoptosis of cardiomyocytes was investigated. Myocardial I/R was simulated in cultured H9c2 cells by 24 h hypoxia followed by 24 h reoxygenation. Using recombinant lentivirus vectors, the inhibition of miR-15a was indicated to significantly reduce cardiomyocyte apoptosis and release of lactate dehydrogenase and malondialdehyde. Conversely, upregulated miR-15a expression was pro-apoptotic. Mothers against decapentaplegic homolog 7 (SMAD7) was identified by bioinformatics analysis as a potential target of miR-15a. Luciferase reporter assays and western blotting for endogenous SMAD7 protein indicated that miR-15a inhibited SMAD7 expression via its 3′-untranslated region. Nuclear levels of nuclear factor-κB (NF-κB) p65 were increased by miR-15a expression and decreased by miR-15a inhibition, which is consistent with the possibility that the inhibition of SMAD7 by miR-15a results in NF-κB activation. These findings suggested that the therapeutic effects of miR-15a inhibition on I/R injury may potentially be explained by its ability to release SMAD-7-dependent NF-κB inhibition. This may provide evidence for miR-15a as a potential therapeutic target for the treatment of cardiac I/R injury.

Cardiac molecular imaging to track left ventricular remodeling in heart failure

Cardiac left ventricular (LV) remodeling is the final common pathway of most primary cardiovascular diseases that manifest clinically as heart failure (HF). The more advanced the systolic HF and LV dysfunction, the worse the prognosis. The knowledge of the molecular, cellular, and neurohormonal mechanisms that lead to myocardial dysfunction and symptomatic HF has expanded rapidly and has allowed sophisticated approaches to understanding and management of the disease. New therapeutic targets for pharmacologic intervention in HF have also been identified through discovery of novel cellular and molecular components of membrane-bound receptor-mediated intracellular signal transduction cascades. Despite all advances, however, the prognosis of systolic HF has remained poor in general. This is, at least in part, related to the (1) relatively late institution of treatment due to reliance on gross functional and structural abnormalities that define the "heart failure phenotype" clinically; (2) remarkable genetic-based interindividual variations in the contribution of each of the many molecular components of cardiac remodeling; and (3) inability to monitor the activity of individual pathways to cardiac remodeling in order to estimate the potential benefits of pharmacologic agents, monitor the need for dose titration, and minimize side effects. Imaging of the recognized ultrastructural components of cardiac remodeling can allow redefinition of heart failure based on its "molecular phenotype," and provide a guide to implementation of "personalized" and "evidence-based" evaluation, treatment, and longitudinal monitoring of the disease beyond what is currently available through randomized controlled clinical trials.

Minute Myocardial Injury as Measured by High-Sensitive Troponin T Serum Levels Predicts the Response to Intracoronary Infusion of Bone Marrow-Derived Mononuclear Cells in Patients With Stable Chronic Post-Infarction Heart Failure: Insights From the TOPCARE-CHD Registry

RATIONALE

Cell-based therapies are a promising option in patients with chronic postinfarction heart failure (ischemic cardiomyopathy [ICM]). However, the responses after intracoronary infusion of autologous bone marrow-derived mononuclear cells (BMCs) are heterogeneous, which may be related to impaired cell retention in patients with ICM. Ischemic injury is associated with upregulation of prototypical chemoattractant cytokines mediating retention and homing of circulating cells. The development of ultrasensitive tests to measure high-sensitive troponin T (hs-TnT) serum levels revealed the presence of ongoing minute myocardial injury even in patients with stable ICM.

OBJECTIVE

To test the hypothesis that serum levels of hs-TnT correlate with cell retention and determine the response to intracoronary BMC application in patients with ICM.

METHODS AND RESULTS

About 157 patients with stable ICM and no substantial impairment of kidney function received intracoronary BMC administration. Immediately prior to cell application, hs-TnT levels to measure myocardial injury and NT-proBNP levels as marker of left ventricular wall stress were determined. Patients with elevated hs-TnT were older and had more severe heart failure. Importantly, only patients with elevated baseline hs-TnT≥15.19 pg/mL (upper tertile) demonstrated a significant (P=0.04) reduction in NT-proBNP serum levels (-250 [-1465; 33] pg/mL; relative reduction -24%) 4 months after BMC administration, whereas NT-proBNP levels remained unchanged in patients in the 2 lower hs-TnT tertiles. The absolute decrease in NT-proBNP at 4 months was inversely correlated with baseline hs-TnT (r=-0.27, P=0.001). Finally, retention of intracoronarily infused, ¹¹¹Indium-labeled cells within the heart was closely associated with hs-TnT levels in patients with chronic ischemic heart failure (P=0.0008, n=10, triple measurements).

CONCLUSIONS

The extent of ongoing myocardial injury as measured by serum levels of hs-TnT predicts the reduction of NT-proBNP serum levels at 4 months after intracoronary BMC administration in patients with ICM, suggesting that the beneficial effects of BMC application on LV remodeling and wall stress are confined to patients with ongoing minute myocardial injury.

CLINICAL TRIAL REGISTRATION

URL: www.clinicaltrials.gov. Unique identifier: NCT00962364.

The predictive value of M30 and oxidative stress for left ventricular remodeling in patients with anterior ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention

BACKGROUND

Left ventricular (LV) remodeling is an important pathophysiological event that develops following acute myocardial infarction and causes LV systolic dysfunction. Mechanisms such as apoptosis, necrosis, and oxidative stress play an important role in LV remodeling.

OBJECTIVES

This study aimed to determine the relationship between the development of LV remodeling and the apoptosis marker M30 in patients with anterior ST-segment elevation myocardial infarction (STEMI) who were treated with primary percutaneous coronary intervention (PCI).

MATERIALS AND METHODS

This retrospective study included 255 consecutive patients (210 men, 45 women, mean age 54.9±11.8 years) with anterior STEMI who were treated with primary PCI. Blood samples were obtained from each patient at admission and 24 h after admission for measurements of M30, M65, oxidative parameters, and biochemical parameters. Transthoracic echocardiography was performed in each patient within 24 h of infarction and 6 months after infarction. LV remodeling was defined as greater than or equal to 20% increase in end-diastolic volume 6 months after primary PCI. The patients were divided into two groups on the basis of 6 months of post-primary PCI follow-up findings: LV remodeling group and non-LV remodeling group.

RESULTS

In all, 60 patients received LV remodeling and 195 did not receive LV remodeling at 6 months after primary PCI. Total oxidative stress, M30 and M65 levels, and the oxidative stress index were significantly higher and the total antioxidant capacity and M65/M30 ratio were lower in the LV remodeling group (P<0.05, for all). Brain natriuretic peptide, M30, and oxidative stress index were independent predictors of LV remodeling (P<0.05 for all). Receiver operating characteristic curve analysis showed that the M30 cut-off value for predicting LV remodeling was 144.9 U/l (80% sensitivity and 77% specificity, P<0.001).

CONCLUSION

In patients with anterior STEMI treated with primary PCI, the apoptosis marker M30 might be useful for predicting LV remodeling and subsequent LV systolic dysfunction.

Baicalin Attenuates Cardiac Dysfunction and Myocardial Remodeling in a Chronic Pressure-Overload Mice Model

Background/Aims: Baicalin has been shown to be effective for various animal models of cardiovascular diseases, such as pulmonary hypertension, atherosclerosis and myocardial ischaemic injury. However, whether baicalin plays a role in cardiac hypertrophy remains unknown. Here we investigated the protective effects of baicalin on cardiac hypertrophy induced by pressure overload and explored the potential mechanisms involved. Methods: C57BL/6J-mice were treated with baicalin or vehicle following transverse aortic constriction or Sham surgery for up to 8 weeks, and at different time points, cardiac function and heart size measurement and histological and biochemical examination were performed. Results: Mice under pressure overload exhibited cardiac dysfunction, high mortality, myocardial hypertrophy, increased apoptosis and fibrosis markers, and suppressed cardiac expression of PPARα and PPARβ/δ. However, oral administration of baicalin improved cardiac dysfunction, decreased mortality, and attenuated histological and biochemical changes described above. These protective effects of baicalin were associated with reduced heart and cardiomyocyte size, lower fetal genes expression, attenuated cardiac fibrosis, lower expression of profibrotic markers, and decreased apoptosis signals in heart tissue. Moreover, we found that baicalin induced PPARα and PPARβ/δ expression in vivo and in vitro. Subsequent experiments demonstrated that long-term baicalin treatment presented no obvious cardiac lipotoxicity. Conclusions: The present results demonstrated that baicalin attenuates pressure overload induced cardiac dysfunction and ventricular remodeling, which would be due to suppressed cardiac hypertrophy, fibrosis, apoptosis and metabolic abnormality.

The role of Epac in the heart

As one of the most important second messengers, 3',5'-cyclic adenosine monophosphate (cAMP) mediates various extracellular signals including hormones and neurotransmitters, and induces appropriate responses in diverse types of cells. Since cAMP was formerly believed to transmit signals through only two direct target molecules, protein kinase A and the cyclic nucleotide-gated channel, the sensational discovery in 1998 of another novel direct effecter of cAMP [exchange proteins directly activated by cAMP (Epac)] attracted a great deal of scientific interest in cAMP signaling. Numerous studies on Epac have since disclosed its important functions in various tissues in the body. Recently, observations of genetically manipulated mice in various pathogenic models have begun to reveal the in vivo significance of previous in vitro or cellular-level findings. Here, we focused on the function of Epac in the heart. Accumulating evidence has revealed that both Epac1 and Epac2 play important roles in the structure and function of the heart under physiological and pathological conditions. Accordingly, developing the ability to regulate cAMP-mediated signaling through Epac may lead to remarkable new therapies for the treatment of cardiac diseases.

Mitochondrial Dynamics as a Therapeutic Target for Treating Cardiac Diseases

Mitochondria are dynamic in nature and are able to shift their morphology between elongated interconnected mitochondrial networks and a fragmented disconnected arrangement by the processes of mitochondrial fusion and fission, respectively. Changes in mitochondrial morphology are regulated by the mitochondrial fusion proteins - mitofusins 1 and 2 (Mfn1 and 2), and optic atrophy 1 (Opa1) as well as the mitochondrial fission proteins - dynamin-related peptide 1 (Drp1) and fission protein 1 (Fis1). Despite having a unique spatial arrangement, cardiac mitochondria have been implicated in a variety of disorders including ischemia-reperfusion injury (IRI), heart failure, diabetes, and pulmonary hypertension. In this chapter, we review the influence of mitochondrial dynamics in these cardiac disorders as well as their potential as therapeutic targets in tackling cardiovascular disease.

Signaling Pathways in Cardiac Myocyte Apoptosis

Cardiovascular diseases, the number 1 cause of death worldwide, are frequently associated with apoptotic death of cardiac myocytes. Since cardiomyocyte apoptosis is a highly regulated process, pharmacological intervention of apoptosis pathways may represent a promising therapeutic strategy for a number of cardiovascular diseases and disorders including myocardial infarction, ischemia/reperfusion injury, chemotherapy cardiotoxicity, and end-stage heart failure. Despite rapid growth of our knowledge in apoptosis signaling pathways, a clinically applicable treatment targeting this cellular process is currently unavailable. To help identify potential innovative directions for future research, it is necessary to have a full understanding of the apoptotic pathways currently known to be functional in cardiac myocytes. Here, we summarize recent progress in the regulation of cardiomyocyte apoptosis by multiple signaling molecules and pathways, with a focus on the involvement of these pathways in the pathogenesis of heart disease. In addition, we provide an update regarding bench to bedside translation of this knowledge and discuss unanswered questions that need further investigation.

Mitochondrial involvement in myocyte death and heart failure

As the heart is an energy-demanding organ, impaired cardiac energy metabolism and mitochondrial function have been inexorably linked to cardiac dysfunction. There is a growing recognition that mitochondrial dysfunction contributes to impaired myocardial energetics and increased oxidative stress in cardiomyopathies, cardiac ischemic damage and heart failure (HF), and mitochondrial permeability transition pore opening has been reported a critical trigger of myocyte death and myocardial remodeling. It is well established that mitochondria play pivotal roles in intracellular signaling in both cell death as well as in cardioprotective pathways. Moreover, recent studies have shown that defects in mitochondrial dynamics affecting biogenesis and turnover are linked to cardiac senescence and HF. Accordingly, there has been an increasing interest in targeting mitochondria for HF therapy. This article reviews the background and recent evidence of mitochondrial involvement in several types of cell death (apoptosis, necrosis and autophagy) occurring in HF. In addition, potential strategies for targeting mitochondria are examined, and their utility in HF therapy considered.

Doxorubicin-induced chronic dilated cardiomyopathy-the apoptosis hypothesis revisited

The chemotherapeutic agent doxorubicin (DOX) has significantly increased survival rates of pediatric and adult cancer patients. However, 10% of pediatric cancer survivors will 10-20 years later develop severe dilated cardiomyopathy (DCM), whereby the exact molecular mechanisms of disease progression after this long latency time remain puzzling. We here revisit the hypothesis that elevated apoptosis signaling or its increased likelihood after DOX exposure can lead to an impairment of cardiac function and cause a cardiac dilation. Based on recent literature evidence, we first argue why a dilated phenotype can occur when little apoptosis is detected. We then review findings suggesting that mature cardiomyocytes are protected against DOX-induced apoptosis downstream, but not upstream of mitochondrial outer membrane permeabilisation (MOMP). This lack of MOMP induction is proposed to alter the metabolic phenotype, induce hypertrophic remodeling, and lead to functional cardiac impairment even in the absence of cardiomyocyte apoptosis. We discuss findings that DOX exposure can lead to increased sensitivity to further cardiomyocyte apoptosis, which may cause a gradual loss in cardiomyocytes over time and a compensatory hypertrophic remodeling after treatment, potentially explaining the long lag time in disease onset. We finally note similarities between DOX-exposed cardiomyocytes and apoptosis-primed cancer cells and propose computational system biology as a tool to predict patient individual DOX doses. In conclusion, combining recent findings in rodent hearts and cardiomyocytes exposed to DOX with insights from apoptosis signal transduction allowed us to obtain a molecularly deeper insight in this delayed and still enigmatic pathology of DCM.

Cardiac myofibroblast engulfment of dead cells facilitates recovery after myocardial infarction

Myocardial infarction (MI) results in the generation of dead cells in the infarcted area. These cells are swiftly removed by phagocytes to minimize inflammation and limit expansion of the damaged area. However, the types of cells and molecules responsible for the engulfment of dead cells in the infarcted area remain largely unknown. In this study, we demonstrated that cardiac myofibroblasts, which execute tissue fibrosis by producing extracellular matrix proteins, efficiently engulf dead cells. Furthermore, we identified a population of cardiac myofibroblasts that appears in the heart after MI in humans and mice. We found that these cardiac myofibroblasts secrete milk fat globule-epidermal growth factor 8 (MFG-E8), which promotes apoptotic engulfment, and determined that serum response factor is important for MFG-E8 production in myofibroblasts. Following MFG-E8-mediated engulfment of apoptotic cells, myofibroblasts acquired antiinflammatory properties. MFG-E8 deficiency in mice led to the accumulation of unengulfed dead cells after MI, resulting in exacerbated inflammatory responses and a substantial decrease in survival. Moreover, MFG-E8 administration into infarcted hearts restored cardiac function and morphology. MFG-E8-producing myofibroblasts mainly originated from resident cardiac fibroblasts and cells that underwent endothelial-mesenchymal transition in the heart. Together, our results reveal previously unrecognized roles of myofibroblasts in regulating apoptotic engulfment and a fundamental importance of these cells in recovery from MI.

Nutritional leucine supplementation attenuates cardiac failure in tumour-bearing cachectic animals

BACKGROUND

The condition known as cachexia presents in most patients with malignant tumours, leading to a poor quality of life and premature death. Although the cancer-cachexia state primarily affects skeletal muscle, possible damage in the cardiac muscle remains to be better characterized and elucidated. Leucine, which is a branched chain amino acid, is very useful for preserving lean body mass. Thus, this amino acid has been studied as a coadjuvant therapy in cachectic cancer patients, but whether this treatment attenuates the effects of cachexia and improves cardiac function remains poorly understood. Therefore, using an experimental cancer-cachexia model, we evaluated whether leucine supplementation ameliorates cachexia in the heart.

METHODS

Male Wistar rats were fed either a leucine-rich or a normoprotein diet and implanted or not with subcutaneous Walker-256 carcinoma. During the cachectic stage (approximately 21 days after tumour implantation), when the tumour mass was greater than 10% of body weight, the rats were subjected to an electrocardiogram analysis to evaluate the heart rate, QT-c, and T wave amplitude. The myocardial tissues were assayed for proteolytic enzymes (chymotrypsin, alkaline phosphatase, cathepsin, and calpain), cardiomyopathy biomarkers (myeloperoxidase, tissue inhibitor of metalloproteinases, and total plasminogen activator inhibitor 1), and caspase-8, -9, -3, and -7 activity.

RESULTS

Both groups of tumour-bearing rats, especially the untreated group, had electrocardiography alterations that were suggestive of ischemia, dilated cardiomyopathy, and sudden death risk. Additionally, the rats in the untreated tumour-bearing group but not their leucine-supplemented littermates exhibited remarkable increases in chymotrypsin activity and all three heart failure biomarkers analysed, including an increase in caspase-3 and -7 activity.

CONCLUSIONS

Our data suggest that a leucine-rich diet could modulate heart damage, cardiomyocyte proteolysis, and apoptosis driven by cancer-cachexia. Further studies must be conducted to elucidate leucine's mechanisms of action, which potentially includes the modulation of the heart's inflammatory process.

Roles of SIRT3 in heart failure: from bench to bedside

Heart failure (HF) represents the most common endpoint of most cardiovascular diseases (CVDs) which are the leading causes of death around the world. Despite the advances in treating CVDs, the prevalence of HF continues to increase. It is believed that better results of prognosis are obtained from prevention rather than additional treatment for HF. Therefore, it is reasonable to prevent the development of CVDs or other complications to HF. Most types of HF are attributed to contractile dysfunction, cardiac hypertrophy or remodeling, and ischemic injuries. SIRT3 is a mitochondrial nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase whose substrates vary from metabolic biogenesis-associated proteins to stress-responsive proteins. In recent years, a number of studies have highlighted the cardio-protective role of SIRT3 and, as such, efforts have been made to induce over-expression or increased activity of this protein. In this review, we provide an overview of the roles of SIRT3 in cardiac hypertrophy induced by pressure overload or agonists and cardiomyocytes ischemic injuries. Moreover, we will introduce the application of SIRT3 agonists in the prevention of cardiac hypertrophy and ischemia reperfusion injury.

Neurohormonal activation in heart failure with reduced ejection fraction

Heart failure with reduced ejection fraction (HFrEF) develops when cardiac output falls as a result of cardiac injury. The most well-recognized of the compensatory homeostatic responses to a fall in cardiac output are activation of the sympathetic nervous system and the renin-angiotensin-aldosterone system (RAAS). In the short term, these 'neurohormonal' systems induce a number of changes in the heart, kidneys, and vasculature that are designed to maintain cardiovascular homeostasis. However, with chronic activation, these responses result in haemodynamic stress and exert deleterious effects on the heart and the circulation. Neurohormonal activation is now known to be one of the most important mechanisms underlying the progression of heart failure, and therapeutic antagonism of neurohormonal systems has become the cornerstone of contemporary pharmacotherapy for heart failure. In this Review, we discuss the effects of neurohormonal activation in HFrEF and highlight the mechanisms by which these systems contribute to disease progression.

MicroRNA-140 is elevated and mitofusin-1 is downregulated in the right ventricle of the Sugen5416/hypoxia/normoxia model of pulmonary arterial hypertension

Heart failure, a major cause of morbidity and mortality in patients with pulmonary arterial hypertension (PAH), is an outcome of complex biochemical processes. In this study, we determined changes in microRNAs (miRs) in the right and left ventricles of normal and PAH rats. Using an unbiased quantitative miR microarray analysis, we found 1) miR-21-5p, miR-31-5 and 3p, miR-140-5 and 3p, miR-208b-3p, miR-221-3p, miR-222-3p, miR-702-3p, and miR-1298 were upregulated (>2-fold; P < 0.05) in the right ventricle (RV) of PAH compared with normal rats; 2) miR-31-5 and 3p, and miR-208b-3p were upregulated (>2-fold; P < 0.05) in the left ventricle plus septum (LV+S) of PAH compared with normal rats; 3) miR-187-5p, miR-208a-3p, and miR-877 were downregulated (>2-fold; P < 0.05) in the RV of PAH compared with normal rats; and 4) no miRs were up- or downregulated with >2-fold in LV+S compared with RV of PAH and normal. Upregulation of miR-140 and miR-31 in the hypertrophic RV was further confirmed by quantitative PCR. Interestingly, compared with control rats, expression of mitofusin-1 (MFN1), a mitochondrial fusion protein that regulates apoptosis, and which is a direct target of miR-140, was reduced in the RV relative to LV+S of PAH rats. We found a correlation between increased miR-140 and decreased MFN1 expression in the hypertrophic RV. Our results also demonstrated that upregulation of miR-140 and downregulation of MFN1 correlated with increased RV systolic pressure and hypertrophy. These results suggest that miR-140 and MFN1 play a role in the pathogenesis of PAH-associated RV dysfunction.

Cardiac lesions induced by 5-fluorouracil in the rabbit

Cardiotoxicity is a rare, but well-recognized complication of treatments with the anti-cancer drug 5-fluorouracil (5FU). The underlying mechanism, however, is not fully elucidated. A spasm of the coronary arteries is often considered to be the leading cause of myocardial ischemia and decreased contractility associated with 5FU. As spasm cannot account for all reported adverse cardiac effects, the present study was undertaken to search for alternative mechanisms. Groups of six rabbits were given either a single intravenous dose of 50 mg/kg 5FU or four intravenous doses of 15 mg/kg 5FU at 7-day intervals. A third group served as control. The heart was removed shortly after death or scheduled sacrifice of the animals, to perform macroscopic and microscopic examinations of the heart and to evidence apoptosis by the TUNEL method. Following a single dose of 50 mg/kg 5FU, all animals rapidly developed a massive hemorrhagic myocardial infarct with spasms of the proximal coronary arteries. Repeated infusions of 15 mg/kg 5FU induced left ventricular hypertrophy, foci of myocardial necrosis, thickening of intra-myocardial arterioles, and disseminated apoptosis in myocardial cells of the epicardium, as well as endothelial cells of the distal coronary arteries. These results indicate that a spasm of the coronary arteries is not the only mechanism of 5FU cardiotoxicity, and that apoptosis of myocardial and endothelial cells can result in inflammatory lesions mimicking toxic myocarditis.

Regenerative Medicine Strategies for Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome (HLHS), the most severe and common form of single ventricle congenital heart lesions, is characterized by hypoplasia of the mitral valve, left ventricle (LV), and all LV outflow structures. While advances in surgical technique and medical management have allowed survival into adulthood, HLHS patients have severe morbidities, decreased quality of life, and a shortened lifespan. The single right ventricle (RV) is especially prone to early failure because of its vulnerability to chronic pressure overload, a mode of failure distinct from ischemic cardiomyopathy encountered in acquired heart disease. As these patients enter early adulthood, an emerging epidemic of RV failure has become evident. Regenerative medicine strategies may help preserve or boost RV function in children and adults with HLHS by promoting angiogenesis and mitigating oxidative stress. Rescuing a RV in decompensated failure may also require the creation of new, functional myocardium. Although considerable hurdles remain before their clinical translation, stem cell therapy and cardiac tissue engineering possess revolutionary potential in the treatment of pediatric and adult patients with HLHS who currently have very limited long-term treatment options.

Cell Death in the Cardiac Myocyte

Loss of cardiac myocytes plays a critical role in the pathogenesis of cardiovascular disorders. A decrease in the number of cardiac myocytes in cardiac diseases results in sustained, irreversible contractile failure of myocardium. Therefore prevention of cardiac cell death is a potential therapeutic strategy for various heart diseases. It is well accepted that three types of phenomena such as apoptosis, necrosis, and autophagy may be involved in myocardial cell death. Apoptosis is a highly regulated process that is promoted via death receptor pathway in the plasma membrane or via mitochondrial pathway. Necrosis is induced via mitochondrial swelling, cell rupture, and subsequent inflammation. Autophagy is a cell survival mechanism that involves degradation and recycling of cytoplasmic components. As compared with the other two mechanisms, autophagy may mediate cell death under specific conditions. These three types of cell death in the myocardium are discussed in this article.

Utility of positron emission tomography for drug development for heart failure

Only about 1 in 5,000 investigational agents in a preclinical stage acquires Food and Drug Administration approval. Among many reasons for this includes an inefficient transition from preclinical to clinical phases, which exponentially increase the cost and the delays the process of drug development. Positron emission tomography (PET) is a nuclear imaging technique that has been used for the diagnosis, risk stratification, and guidance of therapy. However, lately with the advance of radiochemistry and of molecular imaging technology, it became evident that PET could help novel drug development process. By using a PET radioligand to report on receptor occupancy during novel agent therapy, it may help assess the effectiveness, efficacy, and safety of such a new medication in an early preclinical stage and help design successful clinical trials even at a later phase. In this article, we explore the potential implications of PET in the development of new heart failure therapies and review PET's application in the respective pathophysiologic pathways such as myocardial perfusion, metabolism, innervation, inflammation, apoptosis, and cardiac remodeling.

Immunoregulatory mechanisms in Chagas disease: modulation of apoptosis in T-cell mediated immune responses

Background

Chronic Chagas disease presents different clinical manifestations ranging from asymptomatic (namely indeterminate) to severe cardiac and/or digestive. Previous results have shown that the immune response plays an important role, although no all mechanisms are understood. Immunoregulatory mechanisms such as apoptosis are important for the control of Chagas disease, possibly affecting the morbidity in chronic clinical forms. Apoptosis has been suggested to be an important mechanism of cellular response during T. cruzi infection. We aimed to further understand the putative role of apoptosis in Chagas disease and its relation to the clinical forms of the disease.

Methods

Apoptosis of lymphocytes, under antigenic stimuli (soluble T. cruzi antigens – TcAg) where compared to that of non-stimulated cells. Apoptosis was evaluated using the expression of annexin and caspase 3⁺ by T cells and the percentage of cells positive evaluated by flow cytometry. In addition activation and T cell markers were used for the identification of TCD4⁺ and TCD8⁺ subpopulations. The presence of intracellular and plasma cytokines were also evaluated. Analysis of the activation status of the peripheral blood cells showed that patients with Chagas disease presented higher levels of activation determined by the expression of activation markers, after TcAg stimulation. PCR array were used to evaluate the contribution of this mechanism in specific cell populations from patients with different clinical forms of human Chagas disease.

Results

Our results showed a reduced proliferative response associated a high expression of T CD4⁺CD62L⁻ cells in CARD patients when compared with IND group and NI individuals. We also observed that both groups of patients presented a significant increase of CD4⁺ and CD8⁺ T cell subsets in undergoing apoptosis after in vitro stimulation with T. cruzi antigens. In CARD patients, both CD4⁺ and CD8⁺ T cells expressing TNF-α were highly susceptible to undergo apoptosis after in vitro stimulation. Interestingly, the in vitro TcAg stimulation increased considerably the expression of cell death TNF/TNFR superfamily and Caspase family receptors genes in CARD patients.

Conclusions

Taken together, our results suggest that apoptosis may be an important mechanism for the control of morbidity in T. cruzi infection by modulating the expression of apoptosis genes, the cytokine environment and/or killing of effector cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1523-1) contains supplementary material, which is available to authorized users.

Myocardial protective effects of a c-Jun N-terminal kinase inhibitor in rats with brain death

To investigate whether the mitochondrial apoptotic pathway mediates myocardial cell injuries in rats under brain death (BD), and observe the effects and mechanisms of the c‐Jun N‐terminal kinase (JNK) inhibitor SP600125 on cell death in the heart. Forty healthy male Sprague‐Dawley (SD) rats were randomized into four groups: sham group (dural external catheter with no BD); BD group (maintain the induced BD state for 6 hrs); BD + SP600125 group (intraperitoneal injection of SP600125 10 mg/kg 1 hr before inducing BD, and maintain BD for 6 hrs); and BD + Dimethyl Sulphoxide (DMSO) group (intraperitoneal injection of DMSO 1 hr before inducing BD, and maintain BD for 6 hrs). Real‐time quantitative PCR was used to evaluate mRNA levels of Cyt‐c and caspase‐3. Western blot analysis was performed to examine the levels of mitochondrial apoptosis‐related proteins p‐JNK, Bcl‐2, Bax, Cyt‐c and Caspase‐3. TUNEL assay was employed to evaluate myocardial apoptosis. Compared with the sham group, the BD group exhibited increased mitochondrial apoptosis‐related gene expression, accompanied by the elevation of p‐JNK expression and myocardial apoptosis. As the vehicle control, DMSO had no treatment effects. The BD + SP600125 group had decreased p‐JNK expression, and reduced mitochondrial apoptosis‐related gene expression. Furthermore, the apoptosis rate of myocardial cells was reduced. The JNK inhibitor SP600125 could protect myocardial cells under BD through the inhibition of mitochondrial apoptosis‐related pathways.

Effect of the sphingosine kinase 1 selective inhibitor, PF-543 on arterial and cardiac remodelling in a hypoxic model of pulmonary arterial hypertension

Recent studies have demonstrated that the expression of sphingosine kinase 1, the enzyme that catalyses formation of the bioactive lipid, sphingosine 1-phosphate, is increased in lungs from patients with pulmonary arterial hypertension. In addition, Sk1^−/− mice are protected from hypoxic-induced pulmonary arterial hypertension. Therefore, we assessed the effect of the sphingosine kinase 1 selective inhibitor, PF-543 and a sphingosine kinase 1/ceramide synthase inhibitor, RB-005 on pulmonary and cardiac remodelling in a mouse hypoxic model of pulmonary arterial hypertension. Administration of the potent sphingosine kinase 1 inhibitor, PF-543 in a mouse hypoxic model of pulmonary hypertension had no effect on vascular remodelling but reduced right ventricular hypertrophy. The latter was associated with a significant reduction in cardiomyocyte death. The protection involves a reduction in the expression of p53 (that promotes cardiomyocyte death) and an increase in the expression of anti-oxidant nuclear factor (erythroid-derived 2)-like 2 (Nrf-2). In contrast, RB-005 lacked effects on right ventricular hypertrophy, suggesting that sphingosine kinase 1 inhibition might be nullified by concurrent inhibition of ceramide synthase. Therefore, our findings with PF-543 suggest an important role for sphingosine kinase 1 in the development of hypertrophy in pulmonary arterial hypertension.

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PF-543, a sphingosine kinase 1 inhibitor reduces cardiac hypertrophy in a mouse pulmonary arterial hypertension (PAH) model

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This results in reduced cardiomyocyte apoptosis

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PF-543 reduces PARP processing and p53 expression and increases Nrf-2 expression in the right ventricle of mice with PAH

The pathophysiological role of natriuretic peptide-RAAS cross talk in heart failure

Chronic Heart Failure (HF) is still a disease state characterized by elevated morbidity and mortality and represents an unresolved problem for its socio-economic impact. Besides many of the pathophysiological events leading to advanced HF have been widely disclosed in the past decades, the role of neuro-hormonal dysregulation accompanying HF has to be clearly assessed with the objective of better therapeutic approaches in treating such a disease. In the present review article, alongside with a brief re-evaluation of general aspects of HF physiopathology, we summarize recent advances in the cross talk between renin-angiotensin-aldosterone system (RAAS) with natriuretic peptides (NPs) which have been shown to play a relevant role in the development of severe HF. The role of RAAS-NPs interplay has been shown to be crucial in both hemodynamic and tissue remodeling associated to cardiomyocyte dysfunction, leading to advanced impairment of left ventricular performance. On the basis of these results, the development of drugs resetting both RAAS and NPs system seems to be promising for a successful long term treatment of chronic HF.

Myocardial reverse remodeling: how far can we rewind?

Heart failure (HF) is a systemic disease that can be divided into HF with reduced ejection fraction (HFrEF) and with preserved ejection fraction (HFpEF). HFpEF accounts for over 50% of all HF patients and is typically associated with high prevalence of several comorbidities, including hypertension, diabetes mellitus, pulmonary hypertension, obesity, and atrial fibrillation. Myocardial remodeling occurs both in HFrEF and HFpEF and it involves changes in cardiac structure, myocardial composition, and myocyte deformation and multiple biochemical and molecular alterations that impact heart function and its reserve capacity. Understanding the features of myocardial remodeling has become a major objective for limiting or reversing its progression, the latter known as reverse remodeling (RR). Research on HFrEF RR process is broader and has delivered effective therapeutic strategies, which have been employed for some decades. However, the RR process in HFpEF is less clear partly due to the lack of information on HFpEF pathophysiology and to the long list of failed standard HF therapeutics strategies in these patient's outcomes. Nevertheless, new proteins, protein-protein interactions, and signaling pathways are being explored as potential new targets for HFpEF remodeling and RR. Here, we review recent translational and clinical research in HFpEF myocardial remodeling to provide an overview on the most important features of RR, comparing HFpEF with HFrEF conditions.

High-sensitivity cardiac troponin T in geriatric inpatients

BACKGROUND

High-sensitivity cardiac troponin T (hs-cTnT) is detectable in elderly patients without clinical diagnosed cardiovascular disease. Elevated hs-cTnT levels predict increased cardiovascular risks and poor prognosis. The aim of this study was to determine the distribution and associated factors of hs-cTnT in geriatric inpatients without acute coronary syndrome (ACS).

METHODS

Hs-cTnT was measured with a highly sensitive assay in 679 geriatric inpatients without ACS. Patients were further divided into 3 groups according to the tertile of hs-cTnT levels and single and multiple variable analyses were performed to assess the association of hs-cTnT to cardiovascular risk factors, biochemical measurements and echocardiographic abnormalities.

RESULTS

Hs-cTnT was detectable (≥3ng/L) in 98.4% of the subjects and 52.0% of the subjects had hs-cTnT levels ≥14ng/L, which is at the 99th percentile Upper Reference Limit (URL). The levels of hs-cTnT were independently associated with N-terminal pro-brain natriuretic peptide (NT-proBNP), male gender, older age, estimated glomerular filtration rate (eGFR), left ventricular mass index (LVMI), diabetes mellitus (DM) and left ventricular ejection fraction (LVEF). There were no significant differences in hs-cTnT levels between geriatrics patients with stable coronary artery disease (SCAD) and those without SCAD.

CONCLUSION

Hs-cTnT elevation caused by non-ischemic acute conditions was very common in geriatric hospitalized patients. Due to increases in baseline hs-cTnT in the elderly, detection of a rise and/or fall in hs-cTnT levels is essential for determining a diagnosis of ACS or AMI in geriatric patients. Further studies are needed to establish age-specific 99th percentile values of hs-cTnT for elderly individuals.

Effects of Shenqi Fuzheng injection on Fas/FasL protein expression levels in the cardiomyocytes of a mouse model of viral myocarditis

The aim of the present study was to examine the effects of Shenqi Fuzheng injection (SFI) on Fas and FasL protein expression levels in the cardiomyocytes of mice with viral myocarditis (VMC) and to explore the underlying anti-apoptotic mechanisms. A total of 120 male BALB/c mice were randomly divided into five groups as follows: Blank control group, model group, ribavirin group, low-dose SFI group and high-dose SFI group. The VMC model was established by the injection of coxsackievirus group B type 3 and saline, ribavirin or SFI was administered 30 min later. Cardiac samples were harvested from mice in each group on days 3, 10 and 30. Apoptosis of cardiac cells was examined using terminal deoxynucleotidyl transferase dUTP nick-end labeling, and Fas and FasL protein expression levels were detected using immunohistochemistry. Myocardial apoptosis and Fas/FasL protein expression levels were significantly increased in the model group, as compared with the blank group (P<0.01), whereas the apoptotic index (AI) and Fas/FasL protein expression levels of cardiac cells in the high-dose SFI group were significantly decreased compared with those in the model group on day 10 (acute phase; P<0.01). The AI and Fas/FasL protein expression levels of cardiac cells in the low- and high-dose SFI groups were also significantly decreased on day 30 (chronic phase; P<0.01); however, no differences between the high- and low-dose groups were detected. In conclusion, SFI relieves VMC via the downregulation of Fas and FasL protein expression and the inhibition of cell apoptosis.

Rise of serum troponin levels following uncomplicated elective percutaneous coronary interventions in patients without clinical and procedural signs suggestive of myocardial necrosis

INTRODUCTION

The new definition of periprocedural myocardial infarction (type 4a MI) excludes patients without angina and electrocardiographic or echocardiographic changes suggestive of myocardial ischemia even though significant serum troponin elevations occur following percutaneous coronary intervention (PCI).

AIM

To evaluate the incidence and predictors of serum troponin rise following elective PCI in patients without clinical and procedural signs suggestive of myocardial necrosis by using a high-sensitivite troponin assay (hsTnT).

MATERIAL AND METHODS

Three hundred and four patients (mean age: 60.8 ±8.8 years, 204 male) undergoing elective PCI were enrolled. Patients with periprocedural angina, electrocardiographic or echocardiographic signs indicating myocardial ischemia or a visible procedural complication such as dissection or side branch occlusion were excluded. Mild-moderate periprocedural myocardial injury (PMI) and severe PMI were defined as post-PCI (12 h later) elevation of serum hsTnT concentrations to the range of 14-70 ng/l and > 70 ng/l, respectively.

RESULTS

The median pre-procedural hsTnT level was 9.7 ng/l (interquartile range: 7.1-12.2 ng/l). Serum hsTnT concentration elevated (p < 0.001) to 19.4 ng/l (IQR: 12.0-38.8 ng/l) 12 h after PCI. Mild-moderate PMI and severe PMI were detected in 49.3% and 12.2% of patients, respectively. Post-procedural hsTnT levels were significantly higher in multivessel PCI, overlapping stenting, predilatation and postdilatation subgroups. In addition, post-procedural hsTnT levels were correlated (r = 0.340; p < 0.001) with the stent lengths.

CONCLUSIONS

High-sensitivite troponin measurements indicate a high incidence of PMI even though no clinical or procedural signs suggestive of myocardial ischemia exist. Multivessel PCI, overlapping stenting, predilatation, postdilatation and longer stent length are associated with PMI following elective PCI.

Apelin: an endogenous peptide essential for cardiomyogenic differentiation of mesenchymal stem cells via activating extracellular signal-regulated kinase 1/2 and 5

Growing evidence has shown that apelin/APJ system functions as a critical mediator of cardiac development as well as cardiovascular function. Here, we investigated the role of apelin in the cardiomyogenic differentiation of mesenchymal stem cells derived from Wharton's jelly of human umbilical cord in vitro. In this research, we used RNA interference methodology and gene transfection technique to regulate the expression of apelin in Wharton's jelly-derived mesenchymal stem cells and induced cells with a effective cardiac differentiation protocol including 5-azacytidine and bFGF. Four weeks after induction, induced cells assumed a stick-like morphology and myotube-like structures except apelin-silenced cells and the control group. The silencing expression of apelin in Wharton's jelly-derived mesenchymal stem cells decreased the expression of several critical cardiac progenitor transcription factors (Mesp1, Mef2c, NKX2.5) and cardiac phenotypes (cardiac α-actin, β-MHC, cTnT, and connexin-43). Meanwhile, endogenous compensation of apelin contributed to differentiating into cells with characteristics of cardiomyocytes in vitro. Further experiment showed that exogenous apelin peptide rescued the cardiomyogenic differentiation of apelin-silenced mesenchymal stem cells in the early stage (1-4 days) of induction. Remarkably, our experiment indicated that apelin up-regulated cardiac specific genes in Wharton's jelly-derived mesenchymal stem cells via activating extracellular signal-regulated kinase (ERK) 1/2 and 5.

MicroRNAs as early toxicity signatures of doxorubicin in human-induced pluripotent stem cell-derived cardiomyocytes

An in depth investigation at the genomic level is needed to identify early human-relevant cardiotoxicity biomarkers that are induced by drugs and environmental toxicants. The main objective of this study was to investigate the role of microRNAs (miRNAs) as cardiotoxicity biomarkers using human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs) that were exposed to doxorubicin (DOX) as a "gold standard" cardiotoxicant. hiPSC-CMs were exposed to 156 nM DOX for 2 days or for 6 days of repeated exposure, followed by drug washout and incubation in drug-free culture medium up to day 14 after the onset of exposure. The induced miRNAs were profiled using miRNA microarrays, and the analysis of the data was performed using the miRWalk 2.0 and DAVID bioinformatics tools. DOX induced early deregulation of 14 miRNAs (10 up-regulated and 4 down-regulated) and persistent up-regulation of 5 miRNAs during drug washout. Computational miRNA gene target predictions suggested that several DOX-responsive miRNAs might regulate the mRNA expression of genes involved in cardiac contractile function. The hiPSC-CMs exposed to DOX in a range from 39 to 156 nM did not show a significant release of the cytotoxicity marker lactate dehydrogenase (LDH) compared to controls. Quantitative real-time PCR analyses confirmed the early deregulation of miR-187-3p, miR-182-5p, miR-486-3p, miR-486-5p, miR-34a-3p, miR-4423-3p, miR-34c-3p, miR-34c-5p and miR-1303, and also the prolonged up-regulation of miR-182-5p, miR-4423-3p and miR-34c-5p. Thus, we identified and validated miRNAs showing differential DOX-responsive expression before the occurrence of cytotoxicity markers such as LDH, and these miRNAs also demonstrated the significant involvement in heart failure in patients and animal models. These results suggest that the DOX-induced deregulated miRNAs in human CMs may be used as early sensitive cardiotoxicity biomarkers for screening potential drugs and environmental cardiotoxicants with a similar mechanism of action.

MicroRNA-2861 regulates programmed necrosis in cardiomyocyte by impairing adenine nucleotide translocase 1 expression

Necrosis is programmed and is one of the main forms of cell death in the pathological process in cardiac diseases. MicroRNAs (miRNAs) have emerged as key gene regulators in many diseases. However, how miRNAs contribute to programmed necrosis is poorly defined. Here we report that miR-2861 and adenine nucleotide translocase 1 (ANT1) constitute an axis that regulates necrotic cell death in the heart. Our results show that ANT1 inhibits H2O2-induced cardiomyocytes necrosis. ANT1 also antagonizes myocardial necrosis in a mouse ischemia/reperfusion (I/R) model. We further demonstrate that miR-2861 directly binds to the coding sequence of ANT1 and suppresses the expression of ANT1 mRNA and protein. MiR-2861 induces necrotic cell death. In contrast, knockdown of miR-2861 attenuates H2O2-induced necrosis in cardiomyocytes. Also, miR-2861 knockdown protects heart from I/R injury and necrotic cell death in vivo. MiR-2861 regulates necrosis and myocardial infarction through targeting ANT1. Collectively, these data identify miR-2861 and ANT1 as two novel regulators of cardiomyocyte necrosis and myocardial infarction, and suggest potential therapeutic targets in treatment of cardiac diseases.

HECT-Type Ubiquitin E3 Ligase ITCH Interacts With Thioredoxin-Interacting Protein and Ameliorates Reactive Oxygen Species-Induced Cardiotoxicity

Background

The homologous to the E6‐AP carboxyl terminus (HECT)–type ubiquitin E3 ligase ITCH is an enzyme that plays a pivotal role in posttranslational modification by ubiquitin proteasomal protein degradation. Thioredoxin‐interacting protein (TXNIP) is a negative regulator of the thioredoxin system and an endogenous reactive oxygen species scavenger. In the present study, we focused on the functional role of ubiquitin E3 ligase ITCH and its interaction with TXNIP to elucidate the mechanism of cardiotoxicity induced by reactive oxygen species, such as doxorubicin and hydrogen peroxide.

Methods and Results

Protein interaction between TXNIP and ITCH in cardiomyocyte was confirmed by immunoprecipitation assays. Overexpression of ITCH increased proteasomal TXNIP degradation and augmented thioredoxin activity, leading to inhibition of reactive oxygen species generation, p38 MAPK, p53, and subsequent intrinsic pathway cardiomyocyte apoptosis in reactive oxygen species–induced cardiotoxicity. Conversely, knockdown of ITCH using small interfering RNA inhibited TXNIP degradation and resulted in a subsequent increase in cardiomyocyte apoptosis. Next, we generated a transgenic mouse with cardiac‐specific overexpression of ITCH, called the ITCH‐Tg mouse. The expression level of TXNIP in the myocardium in ITCH‐Tg mice was significantly lower than WT littermates. In ITCH‐Tg mice, cardiac dysfunction and remodeling were restored compared with WT littermates after doxorubicin injection and myocardial infarction surgery. Kaplan–Meier analysis revealed that ITCH‐Tg mice had a higher survival rate than WT littermates after doxorubicin injection and myocardial infarction surgery.

Conclusion

We demonstrated, for the first time, that ITCH targets TXNIP for ubiquitin‐proteasome degradation in cardiomyocytes and ameliorates reactive oxygen species–induced cardiotoxicity through the thioredoxin system.

Neutrophil to Lymphocyte Ratio Predicts Left Ventricular Remodeling in Patients with ST Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention

BACKGROUND AND OBJECTIVES

It has been demonstrated that the neutrophil/lymphocyte ratio (NLR) might be a useful marker to predict cardiovascular risk and events. We aimed to investigate the role of the NLR to predict ventricular remodeling (VR) in patients with anterior ST-elevation myocardial infarction (STEMI) who were treated with primary percutaneous coronary intervention.

SUBJECTS AND METHODS

We prospectively included 274 consecutive anterior STEMI patients. Echocardiography was performed during admission and at six months after myocardial infarction. VR was defined as at least 20% increase from baseline in left ventricular end-diastolic volume. Patients were divided into two groups according to their VR status: VR (n=67) and non-VR (n=207). Total and differential leukocyte count, N-terminal pro-brain natriuretic peptide (NT-proBNP) and other biochemical markers were measured at admission and 24 hours later.

RESULTS

Compared with the non-VR group, peak creatine kinase MB (CK-MB), NT-proBNP (24 h), neutrophil/lymphocyte ratio, presence of diabetes, no-reflow frequency and wall motion score index were significantly higher in patients with VR (p<0.05 for all). On multivariate logistic regression analysis, NLR (β=2.000, 95% confidence interval=1.577-2.537, p<0.001) as well as peak CK-MB, NT-proBNP (24 h), WMSI and diabetes incidence were associated with VR. The cutoff value of the neutrophil/lymphocyte ratio obtained by receiver operator characteristic curve analysis was 4.25 for the prediction of VR (sensitivity: 79 %, specificity: 74%).

CONCLUSION

In patients with anterior STEMI, initial NLR and NT-proBNP measured 24 hours after admission may be useful for predicting adverse cardiovascular events including left VR.

Reversal of right ventricular remodeling by dichloroacetate is related to inhibition of mitochondria-dependent apoptosis

Most patients with pulmonary arterial hypertension die from right ventricular failure (RVF). Right ventricular (RV) myocardial apoptosis has an important role in RVF and is regulated by the mitochondria. Dichloroacetate (DCA) can improve cardiac function in RVF, but whether it can regulate myocardial apoptosis via mitochondria is still unknown. In this study, we investigated the effects of DCA on myocardial mitochondria, the mitochondrial apoptosis and other aspects of RV remodeling, including fibrosis and capillary rarefaction. RVF was induced in rats by a single s.c. injection of monocrotaline. After 4 weeks, DCA treatment was started with i.p. injection of 50, 150 or 2007 mg kg(-1) per day during 14 days. Compared with saline-treated RVF animals, treatment with DCA resulted in decreased mean pulmonary arterial pressure and total pulmonary resistance (TPR), and increased cardiac output. The expression of pyruvate dehydrogenase kinase was suppressed, while pyruvate dehydrogenase expression was upregulated with DCA application. DCA treatment was also associated with restored RV mitochondrial function and a reduction in RV hypertrophy, fibrosis, capillary rarefaction and apoptosis. Mitochondria-dependent apoptosis was involved in DCA regulation of RV. The absent correlation between TPR and main parameters in RV suggests that the effects of DCA in the two organ systems are independent. We conclude that DCA improves cardiac function in experimental RVF partly by reversing RV remodeling, restoring mitochondrial function and regulating mitochondria-dependent apoptosis. The study shows that a fear for increased RV apoptosis with DCA treatment is unnecessary and suggests a potential role of DCA in the treatment of RVF.

Cardiac function in BRCA1/2 mutation carriers with history of breast cancer treated with anthracyclines

Animal data suggest that defects in BRCA1/2 genes significantly increase the risk of heart failure and mortality in mice exposed to doxorubicine. Women with BRCA1/2 mutations who develop breast cancer (BC) may receive anthracyclines but their risk of cardiac dysfunction has not been investigated. Our study tested the hypothesis that women with history of BRCA1/2 mutation-associated BC treated with anthracyclines have impaired parameters of cardiac function compared to similarly treated women with history of sporadic BC. Women with history of BC and anthracycline treatment underwent an echocardiographic exam for assessment of primary outcomes, left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS). The sample size of 81 provided 79 % power with two-sided two-sample t test and alpha of 0.05 to detect a clinically meaningful difference in cardiac function of absolute 5 % points difference for LVEF and 2 % points difference for GLS. Of 81 normotensive participants, 39 were BRCA1/2 mutation carriers and 42 in the sporadic group. Mean age was 50 ± 9 years in both groups (P = 0.99) but BRCA1/2 mutation carriers had longer anthracycline treatment-to-enrollment time (7.5 ± 5.3 vs. 4.2 ± 3.3 years, P = 0.001). There were no significant differences in LVEF (P = 0.227) or GLS (P = 0.53) between the groups. LVEF was normal in 91 % of women and subclinical cardiac dysfunction defined as absolute GLS value <18.9 % was seen in 4 (10 %) BRCA1/2 mutation carriers and 7 (17 %) sporadic participants. In this first prospective examination of cardiac function in BRCA1/2 mutation carriers, we found no significant differences in sensitive echocardiographic parameters of cardiac function between BRCA1/2 mutation carriers and women with history of sporadic BC who received anthracycline treatment. In contrast to laboratory animal data, our findings indicate lack of elevated cardiac risk with the use of standard-doses of adjuvant anthracyclines in treatment of BRCA1/2 mutation carriers with early stage BC.

Circulating annexin A5 predicts mortality in patients with heart failure

BACKGROUND

Natriuretic peptides are currently used to predict mortality in patients with heart failure (HF). However, novel independent biomarkers are needed to improve risk stratification in these patients. We hypothesized that annexin A5 (anxA5) would be highly expressed by organs which are generally affected by HF and that circulating anxA5 levels would predict mortality in HF patients.

METHODS

We prospectively determined the diagnostic value of anxA5, N-terminal pro-B-type natriuretic peptide (NT-proBNP), C-reactive protein (CRP) and estimated glomerular filtration rate (eGFR) to predict mortality in 180 HF patients during a median follow-up of 3.6 years. Studies were conducted with anxA5(-/-) mice to investigate the underlying mechanisms.

RESULTS

AnxA5 levels were significantly elevated in HF patients compared to healthy control subjects. Cox regression analysis demonstrated that anxA5, NT-proBNP and eGFR all predict mortality independently. AnxA5 significantly improved the diagnostic efficiency of NT-proBNP alone (improvement of c-statistic from 0.662 to 0.705, P < 0.001) and also combined with eGFR and CRP (improvement of c-statistic from 0.675 to 0.738, P < 0.001) to predict mortality in the Cox regression model. Receiver operating characteristic curve analysis showed that anxA5 predicted 3-year survival (area under curve 0.708) with an optimal cut-off value of 2.24 ng mL(-1) . Using anxA5(-/-) mice, we demonstrated that anxA5 is highly expressed in organs that are often affected by HF including lung, kidney, liver and spleen. Lysis of these organs in vitro resulted in a marked and significant increase in anxA5 concentrations.

CONCLUSION

AnxA5 improves the diagnostic efficiency of conventional biomarkers to predict mortality in HF patients. Whereas natriuretic peptides originate from the myocardium, high circulating anxA5 levels in patients with HF are likely to reflect peripheral organ damage secondary to HF.