Lung ultrasound as a translational approach for non-invasive assessment of heart failure with reduced or preserved ejection fraction in mice

Aims: Heart failure (HF) has become an epidemic and constitutes a major medical, social, and economic problem worldwide. Despite advances in medical treatment, HF prognosis remains poor. The development of efficient therapies is hampered by the lack of appropriate animal models in which HF can be reliably determined, particularly in mice. The development of HF in mice is often assumed based on the presence of cardiac dysfunction, but HF itself is seldom proved. Lung ultrasound (LUS) has become a helpful tool for lung congestion assessment in patients at all stages of HF. We aimed to apply this non-invasive imaging tool to evaluate HF in mouse models of both systolic and diastolic dysfunction. Methods and results: We used LUS to study HF in a mouse model of systolic dysfunction, dilated cardiomyopathy, and in a mouse model of diastolic dysfunction, diabetic cardiomyopathy. LUS proved to be a reliable and reproducible tool to detect pulmonary congestion in mice. The combination of LUS and echocardiography allowed discriminating those mice that develop HF from those that do not, even in the presence of evident cardiac dysfunction. The study showed that LUS can be used to identify the onset of HF decompensation and to evaluate the efficacy of therapies for this syndrome. Conclusions: This novel approach in mouse models of cardiac disease enables for the first time to adequately diagnose HF non-invasively in mice with preserved or reduced ejection fraction, and will pave the way to a better understanding of HF and to the development of new therapeutic approaches.This study was supported by grants from the Spanish Ministerio de Economia y Competitividad (SAF2015-65722-R), Comunidad Autonoma de Madrid (2010-BMD2321, FIBROTEAM Consortium), European Union's FP7 (CardioNeT-ITN-289600, CardioNext-ITN-608027) and the Spanish Instituto de Salud Carlos III (CPII14/00027 to E.L-P, RD12/0042/0054 to B.I. and RD12/0042/066 to P.G.-P. and E.L-P). This work was also supported by the Plan Estatal de I+D+I 2013-2016 - European Regional Development Fund (FEDER) "A way of making Europe", Spain. The CNIC is supported by the Ministry of Economy, Industry and Competitiveness (MINECO) and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (MINECO award SEV-2015-0505).S

Activation of Serine One-Carbon Metabolism by Calcineurin A beta 1 Reduces Myocardial Hypertrophy and Improves Ventricular Function

BACKGROUND In response to pressure overload, the heart develops ventricular hypertrophy that progressively decompensates and leads to heart failure. This pathological hypertrophy is mediated, among others, by the phosphatase calcineurin and is characterized by metabolic changes that impair energy production by mitochondria. OBJECTIVES The authors aimed to determine the role of the calcineurin splicing variant CnA beta 1 in the context of cardiac hypertrophy and its mechanism of action. METHODS Transgenic mice overexpressing CnAb1 specifically in cardiomyocytes and mice lacking the unique C-terminal domain in CnA beta 1 (CnA beta 1(Delta i12) mice) were used. Pressure overload hypertrophy was induced by transaortic constriction. Cardiac function was measured by echocardiography. Mice were characterized using various molecular analyses. RESULTS In contrast to other calcineurin isoforms, the authors show here that cardiac-specific overexpression of CnA beta 1 in transgenic mice reduces cardiac hypertrophy and improves cardiac function. This effect is mediated by activation of serine and one-carbon metabolism, and the production of antioxidant mediators that prevent mitochondrial protein oxidation and preserve ATP production. The induction of enzymes involved in this metabolic pathway by CnAb1 is dependent on mTOR activity. Inhibition of serine and one-carbon metabolism blocks the beneficial effects of CnA beta 1. CnA beta 1(Delta i12) mice show increased cardiac hypertrophy and declined contractility. CONCLUSIONS The metabolic reprogramming induced by CnAb1 redefines the role of calcineurin in the heart and shows for the first time that activation of the serine and one-carbon pathway has beneficial effects on cardiac hypertrophy and function, paving the way for new therapeutic approaches. (J Am Coll Cardiol 2018; 71: 654-67) (C) 2018 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation. This is an open access article under the CC BY-NC-ND license (http://creativecommons. org/licenses/by-nc-nd/4.0/).This work was supported by grants from the European Union (CardioNeT-ITN-289600 and CardioNext-608027 to Dr. Lara-Pezzi; Meet-ITN-317433 to Dr. Enriquez; UE0/MCA1108 to Dr. Acin-Perez), from the Spanish Ministry of Economy and Competitiveness (SAF2015-65722-R and SAF2012-31451 to Dr. Lara-Pezzi; SAF2015-71521-REDC, BFU2013-50448, and SAF2012-32776 to Dr. Enriquez; RyC-2011-07826 to Dr. Acin-Perez; BIO2012-37926 and BIO2015-67580-P to Dr. Vazquez), from the Spanish Carlos III Institute of Health (CPII14/00027 to Dr. Lara-Pezzi; RD12/0042/066 to Drs. Garcia-Pavia and Lara-Pezzi), from the Regional Government of Madrid (2010-BMD-2321 ``Fibroteam´´ to Dr. Lara-Pezzi; 2011-BMD-2402 ``Mitolab´´ to Dr. Enriquez) and the FIS-ISCIII (PRB2-IPT13/0001 and RD12/0042/0056-RIC-RETICS to Dr. Vazquez). This work was also supported by the Plan Estatal de IthornDthornI 2013-2016-European Regional Development Fund (FEDER) ``A way of making Europe,´´ Spain. The CNIC is supported by the Spanish Ministry of Economy and Competitiveness and by the Pro-CNIC Foundation and is a Severo Ochoa Center of Excellence (MINECO award SEV-2015-0505). Drs. Vazquez and Garcia-Pavia have served as consultants for VL39. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. Drs. Padron-Barthe, Villalba-Orero, and Gomez-Salinero contributed equally to this work and are joint first authors. Robyn Shaw, MD, PhD, served as Guest Editor for this paper.S

Correction to: Usefulness of Genetic Testing in Hypertrophic Cardiomyopathy: an Analysis Using Real-World Data

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Truncating FLNC Mutations Are Associated With High-Risk Dilated and Arrhythmogenic Cardiomyopathies

BACKGROUND: Filamin C (encoded by the FLNC gene) is essential for sarcomere attachment to the plasmatic membrane. FLNC mutations have been associated with myofibrillar myopathies, and cardiac involvement has been reported in some carriers. Accordingly, since 2012, the authors have included FLNC in the genetic screening of patients with inherited cardiomyopathies and sudden death. OBJECTIVES: The aim of this study was to demonstrate the association between truncating mutations in FLNC and the development of high-risk dilated and arrhythmogenic cardiomyopathies. METHODS: FLNC was studied using next-generation sequencing in 2,877 patients with inherited cardiovascular diseases. A characteristic phenotype was identified in probands with truncating mutations in FLNC. Clinical and genetic evaluation of 28 affected families was performed. Localization of filamin C in cardiac tissue was analyzed in patients with truncating FLNC mutations using immunohistochemistry. RESULTS: Twenty-three truncating mutations were identified in 28 probands previously diagnosed with dilated, arrhythmogenic, or restrictive cardiomyopathies. Truncating FLNC mutations were absent in patients with other phenotypes, including 1,078 patients with hypertrophic cardiomyopathy. Fifty-four mutation carriers were identified among 121 screened relatives. The phenotype consisted of left ventricular dilation (68%), systolic dysfunction (46%), and myocardial fibrosis (67%); inferolateral negative T waves and low QRS voltages on electrocardiography (33%); ventricular arrhythmias (82%); and frequent sudden cardiac death (40 cases in 21 of 28 families). Clinical skeletal myopathy was not observed. Penetrance was >97% in carriers older than 40 years. Truncating mutations in FLNC cosegregated with this phenotype with a dominant inheritance pattern (combined logarithm of the odds score: 9.5). Immunohistochemical staining of myocardial tissue showed no abnormal filamin C aggregates in patients with truncating FLNC mutations. CONCLUSIONS: Truncating mutations in FLNC caused an overlapping phenotype of dilated and left-dominant arrhythmogenic cardiomyopathies complicated by frequent premature sudden death. Prompt implantation of a cardiac defibrillator should be considered in affected patients harboring truncating mutations in FLNC.Instituto de Salud Carlos III [PI11/0699, PI14/0967, PI14/01477, RD012/0042/0029, RD012/0042/0049, RD012/0042/0066, RD12/0042/0069]; Spanish Ministry of Economy and Competitiveness [SAF2015-71863-REDT]; Plan Nacional de I+D+I; Plan Estatalde I+D+I, European Regional Development Fund; Health in Code SLS

The conformational modification of serpins transforms Leukocyte Elastase Inhibitor into an endonuclease involved in apoptosis.

The best characterized biochemical feature of apoptosis is degradation of genomic DNA into oligonucleosomes. The endonuclease responsible for DNA degradation in caspase-dependent apoptosis is Caspase Activated DNase (CAD). In caspase-independent apoptosis, different endonucleases may be activated according to the cell line and the original insult. Among the known effectors of caspase-independent cell death, L-DNase II (LEI derived DNase II) has been previously characterized by our laboratory. We have thus shown that this endonuclease derives from a serpin super-family member LEI (Leukocyte Elastase Inhibitor) by post-translational modification [Torriglia et al, (1998) Mol. Cell. Biol 18, 3612-3619]. In this work we assessed the molecular mechanism involved in the change of the enzymatic activity of this molecule from an anti-protease to an endonuclease. We report that the cleavage of LEI by elastase at its reactive center loop abolishes its anti-protease activity and leads to a conformational modification that exposes an endonuclease active site and a Nuclear Localization Signal (NLS). This represents a novel molecular mechanism for a complete functional conversion induced by the conformational change of a serpin. We also show that this molecular transformation affects cellular fate and that both endonuclease activity and nuclear translocation of L-DNase II, are needed to induce cell death

Genetic Etiology for Alcohol-Induced Cardiac Toxicity

Alcoholic cardiomyopathy (ACM) is defined by a dilated and impaired left ventricle due to chronic excess alcohol consumption. It is largely unknown which factors determine cardiac toxicity on exposure to alcohol. This study sought to evaluate the role of variation in cardiomyopathy-associated genes in the pathophysiology of ACM, and to examine the effects of alcohol intake and genotype on dilated cardiomyopathy (DCM) severity. The authors characterized 141 ACM cases, 716 DCM cases, and 445 healthy volunteers. The authors compared the prevalence of rare, protein-altering variants in 9 genes associated with inherited DCM. They evaluated the effect of genotype and alcohol consumption on phenotype in DCM. Variants in well-characterized DCM-causing genes were more prevalent in patients with ACM than control subjects (13.5% vs. 2.9%; p = 1.2 ×10 ⁻⁵), but similar between patients with ACM and DCM (19.4%; p = 0.12) and with a predominant burden of titin truncating variants (TTNtv) (9.9%). Separately, we identified an interaction between TTN genotype and excess alcohol consumption in a cohort of DCM patients not meeting ACM criteria. On multivariate analysis, DCM patients with a TTNtv who consumed excess alcohol had an 8.7% absolute reduction in ejection fraction (95% confidence interval: −2.3% to −15.1%; p < 0.007) compared with those without TTNtv and excess alcohol consumption. The presence of TTNtv did not predict phenotype, outcome, or functional recovery on treatment in ACM patients. TTNtv represent a prevalent genetic predisposition for ACM, and are also associated with a worse left ventricular ejection fraction in DCM patients who consume alcohol above recommended levels. Familial evaluation and genetic testing should be considered in patients presenting with ACM

Additional value of screening for minor genes and copy number variants in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is the most prevalent inherited heart disease. Next-generation sequencing (NGS) is the preferred genetic test, but the diagnostic value of screening for minor and candidate genes, and the role of copy number variants (CNVs) deserves further evaluation.Three hundred and eighty-seven consecutive unrelated patients with HCM were screened for genetic variants in the 5 most frequent genes (MYBPC3, MYH7, TNNT2, TNNI3 and TPM1) using Sanger sequencing (N = 84) or NGS (N = 303). In the NGS cohort we analyzed 20 additional minor or candidate genes, and applied a proprietary bioinformatics algorithm for detecting CNVs. Additionally, the rate and classification of TTN variants in HCM were compared with 427 patients without structural heart disease.The percentage of patients with pathogenic/likely pathogenic (P/LP) variants in the main genes was 33.3%, without significant differences between the Sanger sequencing and NGS cohorts. The screening for 20 additional genes revealed LP variants in ACTC1, MYL2, MYL3, TNNC1, GLA and PRKAG2 in 12 patients. This approach resulted in more inconclusive tests (36.0% vs. 9.6%, p<0.001), mostly due to variants of unknown significance (VUS) in TTN. The detection rate of rare variants in TTN was not significantly different to that found in the group of patients without structural heart disease. In the NGS cohort, 4 patients (1.3%) had pathogenic CNVs: 2 deletions in MYBPC3 and 2 deletions involving the complete coding region of PLN.A small percentage of HCM cases without point mutations in the 5 main genes are explained by P/LP variants in minor or candidate genes and CNVs. Screening for variants in TTN in HCM patients drastically increases the number of inconclusive tests, and shows a rate of VUS that is similar to patients without structural heart disease, suggesting that this gene should not be analyzed for clinical purposes in HCM

Distribution of rare variants according to gene-level supporting evidence, ACMG clinical classification and minor allele frequency filtering.

<p>Distribution of rare variants according to gene-level supporting evidence, ACMG clinical classification and minor allele frequency filtering.</p

Rare variants (MAF <0.002) in the 5 most frequent sarcomere genes, 25 genes associated with or candidate for HCM and 24 genes (same panel excluding <i>TTN</i>).

<p>Rare variants (MAF <0.002) in the 5 most frequent sarcomere genes, 25 genes associated with or candidate for HCM and 24 genes (same panel excluding <i>TTN</i>).</p

Classification of the novel variants identified in the NGS cohort.

<p>Classification of the novel variants identified in the NGS cohort.</p