Ankyrin-B dysfunction predisposes to arrhythmogenic cardiomyopathy and is amenable to therapy

Arrhythmogenic cardiomyopathy (ACM) is an inherited arrhythmia syndrome characterized by severe structural and electrical cardiac phenotypes, including myocardial fibrofatty replacement and sudden cardiac death. Clinical management of ACM is largely palliative, owing to an absence of therapies that target its underlying pathophysiology, which stems partially from our limited insight into the condition. Following identification of deceased ACM probands possessing ANK2 rare variants and evidence of ankyrin-B loss of function on cardiac tissue analysis, an ANK2 mouse model was found to develop dramatic structural abnormalities reflective of human ACM, including biventricular dilation, reduced ejection fraction, cardiac fibrosis, and premature death. Desmosomal structure and function appeared preserved in diseased human and murine specimens in the presence of markedly abnormal \u3b2-catenin expression and patterning, leading to identification of a previously unknown interaction between ankyrin-B and \u3b2-catenin. A pharmacological activator of the WNT/\u3b2-catenin pathway, SB-216763, successfully prevented and partially reversed the murine ACM phenotypes. Our findings introduce what we believe to be a new pathway for ACM, a role of ankyrin-B in cardiac structure and signaling, a molecular link between ankyrin-B and \u3b2-catenin, and evidence for targeted activation of the WNT/\u3b2-catenin pathway as a potential treatment for this disease

Biventricular myocardial strain analysis in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) using cardiovascular magnetic resonance feature tracking

BACKGROUND: Fibrofatty degeneration of myocardium in ARVC is associated with wall motion abnormalities. The aim of this study was to examine whether Cardiovascular Magnetic Resonance (CMR) based strain analysis using feature tracking (FT) can serve as a quantifiable measure to confirm global and regional ventricular dysfunction in ARVC patients and support the early detection of ARVC. METHODS: We enrolled 20 patients with ARVC, 30 with borderline ARVC and 22 subjects with a positive family history but no clinical signs of a manifest ARVC. 10 healthy volunteers (HV) served as controls. 15 ARVC patients received genotyping for Plakophilin-2 mutation (PKP-2), of which 7 were found to be positive. Cine MR datasets of all subjects were assessed for myocardial strain using FT (TomTec Diogenes Software). Global strain and strain rate in radial, circumferential and longitudinal mode were assessed for the right and left ventricle. In addition strain analysis at a segmental level was performed for the right ventricular free wall. RESULTS: RV global longitudinal strain rates in ARVC (−0.68 ± 0.36 sec(−1)) and borderline ARVC (−0.85 ± 0.36 sec(−1)) were significantly reduced in comparison with HV (−1.38 ± 0.52 sec(−1), p ≤ 0.05). Furthermore, in ARVC patients RV global circumferential strain and strain rates at the basal level were significantly reduced compared with HV (strain: −5.1 ± 2.7 vs. -9.2 ± 3.6%; strain rate: −0.31 ± 0.13 sec(−1) vs. -0.61 ± 0.21 sec(−1)). Even for patients with ARVC or borderline ARVC and normal RV ejection fraction (n=30) global longitudinal strain rate proved to be significantly reduced compared with HV (−0.9 ± 0.3 vs. -1.4 ± 0.5 sec(−1); p < 0.005). In ARVC patients with PKP-2 mutation there was a clear trend towards a more pronounced impairment in RV global longitudinal strain rate. On ROC analysis RV global longitudinal strain rate and circumferential strain rate at the basal level proved to be the best discriminators between ARVC patients and HV (AUC: 0.9 and 0.92, respectively). CONCLUSION: CMR based strain analysis using FT is an objective and useful measure for quantification of wall motion abnormalities in ARVC. It allows differentiation between manifest or borderline ARVC and HV, even if ejection fraction is still normal

Plakophilin-2: a cell-cell adhesion plaque molecule of selective and fundamental importance in cardiac functions and tumor cell growth

Within the characteristic ensemble of desmosomal plaque proteins, the armadillo protein plakophilin-2 (Pkp2) is known as a particularly important regulatory component in the cytoplasmic plaques of various other cell–cell junctions, such as the composite junctions (areae compositae) of the myocardiac intercalated disks and in the variously-sized and -shaped complex junctions of permanent cell culture lines derived therefrom. In addition, Pkp2 has been detected in certain protein complexes in the nucleoplasm of diverse kinds of cells. Using a novel set of highly sensitive and specific antibodies, both kinds of Pkp2, the junctional plaque-bound and the nuclear ones, can also be localized to the cytoplasmic plaques of diverse non-desmosomal cell–cell junction structures. These are not only the puncta adhaerentia and the fasciae adhaerentes connecting various types of highly proliferative non-epithelial cells growing in culture but also some very proliferative states of cardiac interstitial cells and cardiac myxomata, including tumors growing in situ as well as fetal stages of heart development and cultures of valvular interstitial cells. Possible functions and assembly mechanisms of such Pkp2-positive cell–cell junctions as well as medical consequences are discussed

Evaluation of right and left ventricular function using speckle tracking echocardiography in patients with arrhythmogenic right ventricular cardiomyopathy and their first degree relatives

<p>Abstract</p> <p>Introduction and aim</p> <p>The identification of right ventricular abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) in early stages is still difficult. The aim of this study was to investigate if longitudinal strain based on speckle tracking can detect subtle right (RV) or left ventricular (LV) dysfunction as an early sign of ARVC.</p> <p>Methods and results</p> <p>Seventeen male patients, fulfilling Task force criteria for ARVC, 49 (32–70) years old, nineteen male first degree relatives 29 (19–73) y.o. and twenty-two healthy male volunteers 36 (24–66) y.o participated in the study. Twelve-lead and signal-averaged electrocardiograms were recorded. All subjects underwent echocardiography. LV and RV diameters, peak systolic velocity from tissue Doppler and longitudinal strain based on speckle tracking were measured from the basal and mid segments in both ventricles. RV longitudinal strain measurement was successful in first degree relatives and controls (95 resp. 86%) but less feasible in patients (59%). Results were not systematically different between first degree relatives and controls. Using discriminant analysis, we then developed an index based on echocardiographic parameters. All normal controls had an index < l while patients with abnormal ventricles had an index between 1–4. Some of the first degree relatives deviated from the normal pattern.</p> <p>Conclusion</p> <p>Longitudinal strain of LV and RV segments was significantly lower in patients than in relatives and controls. An index was developed incorporating dimensional and functional echocardiographic parameters. In combination with genetic testing this index might help to detect early phenotype expression in mutation carriers.</p

Ankyrin-B dysfunction predisposes to arrhythmogenic cardiomyopathy and is amenable to therapy

Arrhythmogenic cardiomyopathy (ACM) is an inherited arrhythmia syndrome characterized by severe structural and electrical cardiac phenotypes, including myocardial fibrofatty replacement and sudden cardiac death. Clinical management of ACM is largely palliative, owing to an absence of therapies that target its underlying pathophysiology, which stems partially from our limited insight into the condition. Following identification of deceased ACM probands possessing ANK2 rare variants and evidence of ankyrin-B loss of function on cardiac tissue analysis, an ANK2 mouse model was found to develop dramatic structural abnormalities reflective of human ACM, including biventricular dilation, reduced ejection fraction, cardiac fibrosis, and premature death. Desmosomal structure and function appeared preserved in diseased human and murine specimens in the presence of markedly abnormal β-catenin expression and patterning, leading to identification of a previously unknown interaction between ankyrin-B and β-catenin. A pharmacological activator of the WNT/β-catenin pathway, SB-216763, successfully prevented and partially reversed the murine ACM phenotypes. Our findings introduce what we believe to be a new pathway for ACM, a role of ankyrin-B in cardiac structure and signaling, a molecular link between ankyrin-B and β-catenin, and evidence for targeted activation of the WNT/β-catenin pathway as a potential treatment for this disease

Socio-Economic Variations Determine the Clinical Presentation, Aetiology and Outcome of Infective Endocarditis: a Prospective Cohort Study from the ESC-EORP EURO-ENDO (European Infective Endocarditis) Registry

Background: Infective endocarditis (IE) is a life-threatening disease associated with high mortality and morbidity worldwide. We sought to determine how socio-economic factors might influence its epidemiology, clinical presentation, investigation and management, and outcome, in a large international multi-centre registry. Methods: The EurObservationalProgramme (EORP) of the European Society of Cardiology (ESC) EURO-ENDO registry comprises a prospective cohort of 3113 adult patients admitted for IE in 156 hospitals in 40 countries between January 2016 and March 2018. Patients were separated in 3 groups, according to World Bank economic stratification (Group 1 - high income [75.6%]; Group 2 - upper-middle income [15.4%]; Group 3 - lower-middle income [9.1%]). Results: Group 3 patients were younger (median age [IQR]: Group 1 - 66 [53-75] years; Group 2 - 57 [41-68] years; Group 3 - 33 [26-43] years; p&lt;0.001) with a higher frequency of smokers, intravenous drug use and human immunodeficiency virus (HIV) infection (all p&lt;0.001) and presented later (median [IQR) days since symptom onset: Group 1 - 12 [3-35]; Group 2 - 19 [6-54]; Group 3 - 31 [12-62]; p&lt;0.001) with a higher likelihood of developing congestive heart failure (13.6%; 11.1%; and 22.6%, respectively; p&lt;0.001) and persistent fever (9.8%; 14.2%; 27.9%; p&lt;0.001). Among 2157 (69.3%) patients with theoretical indication for cardiac surgery, surgery was performed less frequently in Group 3 patients (75.5%, 76.8% and 51.3%, respectively p&lt;0.001) who also demonstrated the highest mortality (15.0%, 23.0% and 23.7%, respectively; p&lt;0.001). Conclusions: Socio-economic factors influence the clinical profile of patients presenting with IE across the world. Despite younger age, patients from the poorest countries presented with more frequent complications and higher mortality associated with delayed diagnosis and lower use of surgery

The ESC-EORP EURO-ENDO (European Infective Endocarditis) registry

Aims: The European Society of Cardiology (ESC) EURObservational Research Programme (EORP) European Endocarditis (EURO-ENDO) registry aims to study the care and outcomes of patients diagnosed with infective endocarditis (IE) and compare findings with recommendations from the 2015 ESC Clinical Practice Guidelines for the management of IE and data from the 2001 Euro Heart Survey. Methods and results: Patients (n = 3116) aged over 18 years with a diagnosis of IE based on the ESC 2015 IE diagnostic criteria were prospectively identified between 1 January 2016 and 31 March 2018. Individual patient data were collected across 156 centres and 40 countries. The primary endpoint is all-cause mortality in hospital and at 1 year. Secondary endpoints are 1-year morbidity (all-cause hospitalization, any cardiac surgery, and IE relapse), the clinical, epidemiological, microbiological, and therapeutic characteristics of patients, the number and timing of non-invasive imaging techniques, and adherence to recommendations as stated in the 2015 ESC Clinical Practice Guidelines for the management of IE. Conclusion: EURO-ENDO is an international registry of care and outcomes of patients hospitalized with IE which will provide insights into the contemporary profile and management of patients with this challenging disease