Implications and hidden toxicity of cardiometabolic syndrome and early-stage heart failure in carfilzomib-induced cardiotoxicity

BACKGROUND AND PURPOSE

Cancer therapy-related cardiovascular adverse events (CAEs) in presence of comorbidities, are in the spotlight of the cardio-oncology guidelines. Carfilzomib (Cfz), indicated for relapsed/refractory multiple myeloma (MM), presents with serious CAEs. MM is often accompanied with co-existing comorbidities. However, Cfz use in MM patients with cardiometabolic syndrome (CMS) or in heart failure with reduced ejection fraction (HFrEF), is questionable.

EXPERIMENTAL APPROACH

ApoE-/- and C57BL6/J male mice received 14 weeks Western Diet (WD) (CMS models). C57BL6/J male mice underwent permanent LAD ligation for 14 days (early-stage HFrEF model). CMS- and HFrEF-burdened mice received Cfz for two consecutive or six alternate days. Daily metformin and atorvastatin administrations were performed additionally to Cfz, as prophylactic interventions. Mice underwent echocardiography, while proteasome activity, biochemical and molecular analyses were conducted.

KEY RESULTS

CMS did not exacerbate Cfz left ventricular (LV) dysfunction, whereas Cfz led to metabolic complications in both CMS models. Cfz induced autophagy and Ca2+ homeostasis dysregulation, whereas metformin and atorvastatin prevented Cfz-mediated LV dysfunction and molecular deficits in the CMS-burdened myocardium. Early-stage HFrEF led to depressed LV function and increased protein phosphatase 2A (PP2A) activity. Cfz further increased myocardial PP2A activity, inflammation and Ca2+-cycling dysregulation. Metformin co-administration exerted an anti-inflammatory potential on the myocardium without improving LV function.

CONCLUSION AND IMPLICATIONS

CMS and HFrEF seem to exacerbate Cfz-induced CAEs, by presenting metabolism-related hidden toxicity and PP2A-related cardiac inflammation, respectively. Metformin retains its prophylactic potential in the presence of CMS, while mitigating inflammation and Ca2+ signalling dysregulation in the HFrEF myocardium.

Early microvascular coronary endothelial dysfunction precedes pembrolizumab-induced cardiotoxicity. Preventive role of high dose of atorvastatin

Immune checkpoint inhibitors (ICIs) exhibit remarkable antitumor activity and immune-related cardiotoxicity of unknown pathomechanism. The aim of the study was to investigate the ICI class-dependent cardiotoxicity in vitro and pembrolizumab's (Pem's) cardiotoxicity in vivo, seeking for translational prevention means. Cytotoxicity was investigated in primary cardiomyocytes and splenocytes, incubated with ipilimumab, Pem and avelumab. Pem's cross-reactivity was assessed by circular dichroism (CD) on biotechnologically produced human and murine PD-1 and in silico. C57BL6/J male mice received IgG4 or Pem for 2 and 5 weeks. Echocardiography, histology, and molecular analyses were performed. Coronary blood flow velocity mapping and cardiac magnetic resonance imaging were conducted at 2 weeks. Human EA.hy926 endothelial cells were incubated with Pem-conditioned media from human mononuclear cells, in presence and absence of statins and viability and molecular signaling were assessed. Atorvastatin (20 mg/kg, daily) was administered in vivo, as prophylaxis. Only Pem exerted immune-related cytotoxicity in vitro. Pem's cross-reactivity with the murine PD-1 was confirmed by CD and docking. In vivo, Pem initiated coronary endothelial and diastolic dysfunction at 2 weeks and systolic dysfunction at 5 weeks. At 2 weeks, Pem induced ICAM-1 and iNOS expression and intracardiac leukocyte infiltration. At 5 weeks, Pem exacerbated endothelial activation and triggered cardiac inflammation. Pem led to immune-related cytotoxicity in EA.hy926 cells, which was prevented by atorvastatin. Atorvastatin mitigated functional deficits, by inhibiting endothelial dysfunction in vivo. We established for the first time an in vivo model of Pem-induced cardiotoxicity. Coronary endothelial dysfunction precedes Pem-induced cardiotoxicity, whereas atorvastatin emerges as a novel prophylactic therapy.

Comprehensive Analysis of 1-Year-Old Female Apolipoprotein E-Deficient Mice Reveals Advanced Atherosclerosis with Vulnerable Plaque Characteristics

Apolipoprotein E-knockout (Apoe-/-) mice constitute the most widely employed animal model of atherosclerosis. Deletion of Apoe induces profound hypercholesterolemia and promotes the development of atherosclerosis. However, despite its widespread use, the Apoe-/- mouse model remains incompletely characterized, especially at late time points and advanced disease stages. Thus, it is unclear how late atherosclerotic plaques compare to earlier ones in terms of lipid deposition, calcification, macrophage accumulation, smooth muscle cell presence, or plaque necrosis. Additionally, it is unknown how cardiac function and hemodynamic parameters are affected at late disease stages. Here, we used a comprehensive analysis based on histology, fluorescence microscopy, and Doppler ultrasonography to show that in normal chow diet-fed Apoe-/- mice, atherosclerotic lesions at the level of the aortic valve evolve from a more cellular macrophage-rich phenotype at 26 weeks to an acellular, lipid-rich, and more necrotic phenotype at 52 weeks of age, also marked by enhanced lipid deposition and calcification. Coronary artery atherosclerotic lesions are sparse at 26 weeks but ubiquitous and extensive at 52 weeks; yet, left ventricular function was not significantly affected. These findings demonstrate that atherosclerosis in Apoe-/- mice is a highly dynamic process, with atherosclerotic plaques evolving over time. At late disease stages, histopathological characteristics of increased plaque vulnerability predominate in combination with frequent and extensive coronary artery lesions, which nevertheless may not necessarily result in impaired cardiac function.

Ergophysiological evaluation of heart failure patients with reduced ejection fraction undergoing exercise-based cardiac rehabilitation: A systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aims to explore in heart failure (HF) patients with reduced ejection fraction (EF) undergoing exercise-based cardiac rehabilitation the following: 1) the comparison of temporal changes between peak oxygen uptake (VO2peak) and first ventilatory threshold (VO2VT1), 2) the association of VO2peak and VO2VT1 changes with physiological factors, and 3) the differential effects of continuous aerobic exercise (CAE) and interval training (IT) on VO2peak and VO2VT1.

METHODS

A systematic literature search was conducted in PubMed, CENTRAL, and Scopus. Inclusion criteria were 1) original research articles using exercise-based cardiac rehabilitation, 2) stable HF patients with reduced EF, 3) available values of VO2peak and VO2VT1 (in mL/kg/min) both at baseline and after exercise training with comparison between these time points.

RESULTS

Among the 30 eligible trials, 24 used CAE, 5 IT, and one CAE and IT. Multivariable meta-regression with duration of exercise training and percentage of males as independent variables and the change in VO2peak as a dependent variable showed that the change in VO2peak was negatively associated with duration of exercise training (coefficient=-0.061, p=0.027), implying the possible existence of a waning effect of exercise training on VO2peak in the long term. Multivariable meta-regression demonstrated that both age (coefficient=-0.140, p<0.001) and EF (coefficient=-0.149, p<0.001) could predict the change in VO2VT1, whereas only age (coefficient=-0.095, p=0.022), but not EF (coefficient = 0.082, p = 0.100), could predict the change in VO2peak. The posttraining peak respiratory exchange ratio, as an index of maximum effort during exercise testing, correlated positively with the change in VO2peak (coefficient=-0.021, p=0.044). The exercise-induced changes of VO2peak (p = 0.438) and VO2VT1 (p = 0.474) did not differ between CAE and IT groups.

CONCLUSIONS

Improvement of endurance capacity during cardiac rehabilitation may be detected more accurately with the assessment of VO2VT1 rather than VO2peak.

Safety and long-term outcomes of remote cardiac rehabilitation in coronary heart disease patients: A systematic review

Objective

To systematically review the safety and the long-term mortality and morbidity risk-rates of the remotely-delivered cardiac rehabilitation (RDCR) interventions in coronary heart disease (CHD) patients.

Methods

The protocol was registered in the International Prospective Register of Systematic Reviews (CRD42023455471). Five databases (Pubmed, Scopus, Cochrane Central Register of Controlled Trials in the Cochrane Library, Cinahl and Web of Science) were reviewed from January 2012 up to August 2023. Inclusion criteria were: (a) randomized controlled trials, (b) RDCR implementation of at least 12 weeks duration, (c) assessment of safety, rates of serious adverse events (SAEs) and re-hospitalization incidences at endpoints more than 6 months. Three reviewers independently performed data extraction and assessed the risk of bias using the Cochrane Risk of Bias tool.

Results

14 studies were identified involving 2012 participants and a range of RDCR duration between 3 months to 1 year. The incidence rate of exercise-related SAEs was estimated at 1 per 53,770 patient-hours of RDCR exercise. A non-statistically significant reduction in the re-hospitalization rates and the days lost due to hospitalization was noticed in the RDCR groups. There were no exercise-related deaths. The overall study quality was of low risk.

Conclusions

RDCR can act as a safe alternative delivery mode of cardiac rehabilitation (CR). The low long-term rates of reported SAEs and re-hospitalization incidences of the RDCR could enhance the uptake rates of CR interventions. However, further investigation is needed in larger populations and longer assessment points.

Standardised Exercise Prescription for Patients with Chronic Coronary Syndrome and/or Heart Failure: A Consensus Statement from the EXPERT Working Group

Whereas exercise training, as part of multidisciplinary rehabilitation, is a key component in the management of patients with chronic coronary syndrome (CCS) and/or congestive heart failure (CHF), physicians and exercise professionals disagree among themselves on the type and characteristics of the exercise to be prescribed to these patients, and the exercise prescriptions are not consistent with the international guidelines. This impacts the efficacy and quality of the intervention of rehabilitation. To overcome these barriers, a digital training and decision support system [i.e. EXercise Prescription in Everyday practice & Rehabilitative Training (EXPERT) tool], i.e. a stepwise aid to exercise prescription in patients with CCS and/or CHF, affected by concomitant risk factors and comorbidities, in the setting of multidisciplinary rehabilitation, was developed. The EXPERT working group members reviewed the literature and formulated exercise recommendations (exercise training intensity, frequency, volume, type, session and programme duration) and safety precautions for CCS and/or CHF (including heart transplantation). Also, highly prevalent comorbidities (e.g. peripheral arterial disease) or cardiac devices (e.g. pacemaker, implanted cardioverter defibrillator, left-ventricular assist device) were considered, as well as indications for the in-hospital phase (e.g. after coronary revascularisation or hospitalisation for CHF). The contributions of physical fitness, medications and adverse events during exercise testing were also considered. The EXPERT tool was developed on the basis of this evidence. In this paper, the exercise prescriptions for patients with CCS and/or CHF formulated for the EXPERT tool are presented. Finally, to demonstrate how the EXPERT tool proposes exercise prescriptions in patients with CCS and/or CHF with different combinations of CVD risk factors, three patient cases with solutions are presented.

CTH/MPST double ablation results in enhanced vasorelaxation and reduced blood pressure via upregulation of the eNOS/sGC pathway

Hydrogen sulfide (H₂S), a gasotransmitter with protective effects in the cardiovascular system, is endogenously generated by three main enzymatic pathways: cystathionine gamma lyase (CTH), cystathionine beta synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (MPST) enzymes. CTH and MPST are the predominant sources of H₂S in the heart and blood vessels, exhibiting distinct effects in the cardiovascular system. To better understand the impact of H₂S in cardiovascular homeostasis, we generated a double Cth/Mpst knockout (Cth/Mpst ^-/- ) mouse and characterized its cardiovascular phenotype. CTH/MPST-deficient mice were viable, fertile and exhibited no gross abnormalities. Lack of both CTH and MPST did not affect the levels of CBS and H₂S-degrading enzymes in the heart and the aorta. Cth/Mpst ^-/- mice also exhibited reduced systolic, diastolic and mean arterial blood pressure, and presented normal left ventricular structure and fraction. Aortic ring relaxation in response to exogenously applied H₂S was similar between the two genotypes. Interestingly, an enhanced endothelium-dependent relaxation to acetylcholine was observed in mice in which both enzymes were deleted. This paradoxical change was associated with upregulated levels of endothelial nitric oxide synthase (eNOS) and soluble guanylate cyclase (sGC) α1 and β1 subunits and increased NO-donor-induced vasorelaxation. Administration of a NOS-inhibitor, increased mean arterial blood pressure to a similar extent in wild-type and Cth/Mpst ^-/- mice. We conclude that chronic elimination of the two major H₂S sources in the cardiovascular system, leads to an adaptive upregulation of eNOS/sGC signaling, revealing novel ways through which H₂S affects the NO/cGMP pathway.

How to optimize the adherence to a guideline-directed medical therapy in the secondary prevention of cardiovascular diseases: a clinical consensus statement from the European Association of Preventive Cardiology

A key factor to successful secondary prevention of cardiovascular disease (CVD) is optimal patient adherence to treatment. However, unsatisfactory rates of adherence to treatment for CVD risk factors and CVD have been observed consistently over the last few decades. Hence, achieving optimal adherence to lifestyle measures and guideline-directed medical therapy in secondary prevention and rehabilitation is a great challenge to many healthcare professionals. Therefore, in this European Association of Preventive Cardiology clinical consensus document, a modern reappraisal of the adherence to optimal treatment is provided, together with simple, practical, and feasible suggestions to achieve this goal in the clinical setting, focusing on evidence-based concepts.

Epigenetics in the primary and secondary prevention of cardiovascular disease: influence of exercise and nutrition

Increasing evidence links changes in epigenetic systems, such as DNA methylation, histone modification, and non-coding RNA expression, to the occurrence of cardiovascular disease (CVD). These epigenetic modifications can change genetic function under influence of exogenous stimuli and can be transferred to next generations, providing a potential mechanism for inheritance of behavioural intervention effects. The benefits of exercise and nutritional interventions in the primary and secondary prevention of CVD are well established, but the mechanisms are not completely understood. In this review, we describe the acute and chronic epigenetic effects of physical activity and dietary changes. We propose exercise and nutrition as potential triggers of epigenetic signals, promoting the reshaping of transcriptional programmes with effects on CVD phenotypes. Finally, we highlight recent developments in epigenetic therapeutics with implications for primary and secondary CVD prevention.

Effectiveness of Home-Based Cardiac Rehabilitation, Using Wearable Sensors, as a Multicomponent, Cutting-Edge Intervention: A Systematic Review and Meta-Analysis

Exercise-based cardiac rehabilitation is a highly recommended intervention towards the advancement of the cardiovascular disease (CVD) patients’ health profile; though with low participation rates. Although home-based cardiac rehabilitation (HBCR) with the use of wearable sensors is proposed as a feasible alternative rehabilitation model, further investigation is needed. This systematic review and meta-analysis aimed to evaluate the effectiveness of wearable sensors-assisted HBCR in improving the CVD patients’ cardiorespiratory fitness (CRF) and health profile. PubMed, Scopus, Cinahl, Cochrane Library, and PsycINFO were searched from 2010 to January 2022, using relevant keywords. A total of 14 randomized controlled trials, written in English, comparing wearable sensors-assisted HBCR to center-based cardiac rehabilitation (CBCR) or usual care (UC), were included. Wearable sensors-assisted HBCR significantly improved CRF when compared to CBCR (Hedges’ g = 0.22, 95% CI 0.06, 0.39; I2 = 0%; p = 0.01), whilst comparison of HBCR to UC revealed a nonsignificant effect (Hedges’ g = 0.87, 95% CI −0.87, 1.85; I2 = 96.41%; p = 0.08). Effects on physical activity, quality of life, depression levels, modification of cardiovascular risk factors/laboratory parameters, and adherence were synthesized narratively. No significant differences were noted. Technology tools are growing fast in the cardiac rehabilitation era and promote exercise-based interventions into a more home-based setting. Wearable-assisted HBCR presents the potential to act as an adjunct or an alternative to CBCR.

European Society of Cardiology Quality Indicators for Cardiovascular Disease Prevention: developed by the Working Group for Cardiovascular Disease Prevention Quality Indicators in collaboration with the European Association for Preventive Cardiology of the European Society of Cardiology

AIMS

To develop a set of quality indicators (QIs) for the evaluation of the care and outcomes for atherosclerotic cardiovascular disease (ASCVD) prevention.

METHODS AND RESULTS

The Quality Indicator Committee of the European Society of Cardiology (ESC) formed the Working Group for Cardiovascular Disease Prevention Quality Indicators in collaboration with Task Force members of the 2021 ESC Guidelines on Cardiovascular Disease Prevention in Clinical Practice and the European Association of Preventive Cardiology (EAPC). We followed the ESC methodology for QI development, which involved (i) the identification of the key domains of care for ASCVD prevention by constructing a conceptual framework of care, (ii) the development of candidate QIs by conducting a systematic review of the literature, (iii) the selection of the final set of QIs using a modified Delphi method, and (iv) the evaluation of the feasibility of the developed QIs. In total, 17 main and 14 secondary QIs were selected across six domains of care for ASCVD prevention: (i) structural framework, (ii) risk assessment, (iii) care for people at risk for ASCVD, (iv) care for patients with established ASCVD, (v) patient education and experience, and (vi) outcomes.

CONCLUSION

We present the 2021 ESC QIs for Cardiovascular Disease Prevention, which have been co-constructed with EAPC using the ESC methodology for QI development. These indicators are supported by evidence from the literature, underpinned by expert consensus and aligned with the 2021 ESC Guidelines on Cardiovascular Disease Prevention in Clinical Practice to offer a mechanism for the evaluation of ASCVD prevention care and outcomes.

Galectin-3 interferes with tissue repair and promotes cardiac dysfunction and comorbidities in a genetic heart failure model

Galectin-3, a biomarker for heart failure (HF), has been associated with myocardial fibrosis. However, its causal involvement in HF pathogenesis has been questioned in certain models of cardiac injury-induced HF. To address this, we used desmin-deficient mice (des-/-), a model of progressive HF characterized by cardiomyocyte death, spontaneous inflammatory responses sustaining fibrosis, and galectin-3 overexpression. Genetic ablation or pharmacological inhibition of galectin-3 led to improvement of cardiac function and adverse remodeling features including fibrosis. Over the course of development of des-/- cardiomyopathy, monitored for a period of 12 months, galectin-3 deficiency specifically ameliorated the decline in systolic function accompanying the acute inflammatory phase (4-week-old mice), whereas a more pronounced protective effect was observed in older mice, including the preservation of diastolic function. Interestingly, the cardiac repair activities during the early inflammatory phase were restored under galectin-3 deficiency by increasing the proliferation potential and decreasing apoptosis of fibroblasts, while galectin-3 absence modulated macrophage-fibroblast coupled functions and suppressed both pro-fibrotic activation of cardiac fibroblasts and pro-fibrotic gene expression in the des-/- heart. In addition, galectin-3 also affected the emphysema-like comorbid pathology observed in the des-/- mice, as its absence partially normalized lung compliance. Collectively galectin-3 was found to be causally involved in cardiac adverse remodeling, inflammation, and failure by affecting functions of cardiac fibroblasts and macrophages. In concordance with this role, the effectiveness of pharmacological inhibition in ameliorating cardiac pathology features establishes galectin-3 as a valid intervention target for HF, with additive benefits for treatment of associated comorbidities, such as pulmonary defects. Schematic illustrating top to bottom, the detrimental role of galectin-3 (Gal3) in heart failure progression: desmin deficiency-associated spontaneous myocardial inflammation accompanying cardiac cell death (reddish dashed border) is characterized by infiltration of macrophages (round cells) and up-regulation of Lgals3 (encoding secretable galectin-3, green) and detrimental macrophage-related genes (Ccr2 and Arg1). In this galectin-3-enriched milieu, the early up-regulation of profibrotic gene expression (Tgfb1, Acta2, Col1a1), in parallel to the suppression of proliferative activities and a potential of senescence induction by cardiac fibroblasts (spindle-like cells), collectively promote des-/- cardiac fibrosis and dysfunction establishing heart failure (left panel). Additionally, galectin-3+ macrophage-enrichment accompanies the development of emphysema-like lung comorbidities. In the absence of galectin-3 (right panel), the effect of macrophage-fibroblast dipole and associated events are modulated (grey color depicts reduced expression or activities) leading to attenuated cardiac pathology in the des-/-Lgals3-/- mice. Pulmonary comorbidities are also limited.

Exercise intensity assessment and prescription in cardiovascular rehabilitation and beyond: why and how: a position statement from the Secondary Prevention and Rehabilitation Section of the European Association of Preventive Cardiology

A proper determination of the exercise intensity is important for the rehabilitation of patients with cardiovascular disease (CVD) since it affects the effectiveness and medical safety of exercise training. In 2013, the European Association of Preventive Cardiology (EAPC), together with the American Association of Cardiovascular and Pulmonary Rehabilitation and the Canadian Association of Cardiac Rehabilitation, published a position statement on aerobic exercise intensity assessment and prescription in cardiovascular rehabilitation (CR). Since this publication, many subsequent papers were published concerning the determination of the exercise intensity in CR, in which some controversies were revealed and some of the commonly applied concepts were further refined. Moreover, how to determine the exercise intensity during resistance training was not covered in this position paper. In light of these new findings, an update on how to determine the exercise intensity for patients with CVD is mandatory, both for aerobic and resistance exercises. In this EAPC position paper, it will be explained in detail which objective and subjective methods for CR exercise intensity determination exist for aerobic and resistance training, together with their (dis)advantages and practical applications.

OUP accepted manuscript

This article provides an overview of the recommendations of the Aviation and Occupational Cardiology Task Force of the European Association of Preventive Cardiology on returning individuals to work in high-hazard occupations (such as flying, diving, and workplaces that are remote from healthcare facilities) following symptomatic Coronavirus Disease 2019 (COVID-19) infection. This process requires exclusion of significant underlying cardiopulmonary disease and this consensus statement (from experts across the field) outlines the appropriate screening and investigative processes that should be undertaken. The recommended response is based on simple screening in primary healthcare to determine those at risk, followed by first line investigations, including an exercise capacity assessment, to identify the small proportion of individuals who may have circulatory, pulmonary, or mixed disease. These individuals can then receive more advanced, targeted investigations. This statement provides a pragmatic, evidence-based approach for those (in all occupations) to assess employee health and capacity prior to a return to work following severe disease, or while continuing to experience significant post-COVID-19 symptoms (so-called ‘long-COVID’ or post-COVID-19 syndrome).

Cardiovascular risk in high-hazard occupations: the role of occupational cardiology

Work is beneficial for health, but many individuals develop cardiovascular disease (CVD) during their working lives. Occupational cardiology is an emerging field that combines traditional cardiology sub-specialisms with prevention and risk management unique to specific employment characteristics and conditions. In some occupational settings incapacitation through CVD has the potential to be catastrophic due to the nature of work and/or the working environment. These are often termed 'hazardous' or 'high-hazard' occupations. Consequently, many organizations that employ individuals in high-hazard roles undertake pre-employment medicals and periodic medical examinations to screen for CVD. The identification of CVD that exceeds predefined employer (or regulatory body) risk thresholds can result in occupational restriction, or disqualification, which may be temporary or permanent. This article will review the evidence related to occupational cardiology for several high-hazard occupations related to aviation and space, diving, high altitude, emergency workers, commercial transportation, and the military. The article will focus on environmental risk, screening, surveillance, and risk management for the prevention of events precipitated by CVD. Occupational cardiology is a challenging field that requires a broad understanding of general cardiology, environmental, and occupational medicine principles. There is a current lack of consensus and contemporary evidence which requires further research. Provision of evidence-based, but individualized, risk stratification and treatment plans is required from specialists that understand the complex interaction between work and the cardiovascular system. There is a current lack of consensus and contemporary evidence in occupational cardiology and further research is required.

The Interplay between Myocardial Fibrosis, Strain Imaging and Collagen Biomarkers in Adults with Repaired Tetralogy of Fallot

Background: We sought to assess the interplay between right ventricle (RV) fibrosis, biventricular dysfunction based on global longitudinal strain (GLS) analysis, and biomarkers such as Galectin-3 (Gal-3), procollagen type III (PCIII), and NTproBNP. Methods: We studied 35 adult patients with rToF. All patients underwent a cardiac magnetic resonance (CMR) scan including feature tracking for deformation imaging. Blood biomarkers were measured. Results: LGE RV was detected in all patients, mainly at surgical sites. Patients with the highest RV LGE scoring had greater RV dilatation and dysfunction whereas left ventricular (LV) function was preserved. LV GLS correlated with RV total fibrosis score (p = 0.007). A LV GLS value of −15.9% predicted LGE RV score > 8 (AUC 0.754 (p = 0.02)). Neither RV GLS nor biomarker levels were correlated with the extent of RV fibrosis. A cut-off value for NTproBNP of 145.25 pg/mL predicted LGE RV score > 8 points (AUC 0.729, (p = 0.03)). A cut-off value for Gal-3 of 7.42 ng/mL predicted PR Fraction > 20% [AUC 0.704, (p = 0.05)]. Conclusions: A significant extent of RV fibrosis was mainly detected at surgical sites of RV, affecting RV performance. CMR-FT reveals subtle LV dysfunction in rToF patients, due to decreased performance of the fibrotic RV. Impaired LV function and elevated NTproBNP in rToF reflect a dysfunctional fibrotic RV.

Protein tyrosine phosphatase receptor zeta 1 deletion triggers defective heart morphogenesis in mice and zebrafish

Protein tyrosine phosphatase receptor-ζ1 (PTPRZ1) is a transmembrane tyrosine phosphatase receptor highly expressed in embryonic stem cells. In the present work, gene expression analyses of Ptprz1^−/− and Ptprz1^+/+ mice endothelial cells and hearts pointed to an unidentified role of PTPRZ1 in heart development through the regulation of heart-specific transcription factor genes. Echocardiography analysis in mice identified that both systolic and diastolic functions are affected in Ptprz1^−/− compared with Ptprz1^+/+ hearts, based on a dilated left ventricular (LV) cavity, decreased ejection fraction and fraction shortening, and increased angiogenesis in Ptprz1^−/− hearts, with no signs of cardiac hypertrophy. A zebrafish ptprz1^−/− knockout was also generated and exhibited misregulated expression of developmental cardiac markers, bradycardia, and defective heart morphogenesis characterized by enlarged ventricles and defected contractility. A selective PTPRZ1 tyrosine phosphatase inhibitor affected zebrafish heart development and function in a way like what is observed in the ptprz1^−/− zebrafish. The same inhibitor had no effect in the function of the adult zebrafish heart, suggesting that PTPRZ1 is not important for the adult heart function, in line with data from the human cell atlas showing very low to negligible PTPRZ1 expression in the adult human heart. However, in line with the animal models, Ptprz1 was expressed in many different cell types in the human fetal heart, such as valvar, fibroblast-like, cardiomyocytes, and endothelial cells. Collectively, these data suggest that PTPRZ1 regulates cardiac morphogenesis in a way that subsequently affects heart function and warrant further studies for the involvement of PTPRZ1 in idiopathic congenital cardiac pathologies.

NEW & NOTEWORTHY Protein tyrosine phosphatase receptor ζ1 (PTPRZ1) is expressed in fetal but not adult heart and seems to affect heart development. In both mouse and zebrafish animal models, loss of PTPRZ1 results in dilated left ventricle cavity, decreased ejection fraction, and fraction shortening, with no signs of cardiac hypertrophy. PTPRZ1 also seems to be involved in atrioventricular canal specification, outflow tract morphogenesis, and heart angiogenesis. These results suggest that PTPRZ1 plays a role in heart development and support the hypothesis that it may be involved in congenital cardiac pathologies.

Crosstalk between coagulation and complement activation promotes cardiac dysfunction in arrhythmogenic right ventricular cardiomyopathy

Aims: We previously found that complement components are upregulated in the myocardium of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), and inhibiting the complement receptor C5aR reduces disease severity in desmin knockout (Des-/- ) mice, a model for ARVC. Here, we examined the mechanism underlying complement activation in ARVC, revealing a potential new therapeutic target. Methods: First, immunostaining, RT-PCR and western blot were used to detect the expression levels of complement and coagulation factors. Second, we knocked out the central complement component C3 in Des-/- mice (ARVC model) by crossing Des-/- mice with C3-/- mice to explore whether complement system activation occurs independently of the conventional pathway. Then, we evaluated whether a targeted intervention to coagulation system is effective to reduce myocardium injury. Finally, the plasma sC5b9 level was assessed to investigate the role in predicting adverse cardiac events in the ARVC cohort. Results: The complement system is activated in the myocardium in ARVC. Autoantibodies against myocardial proteins provided a possible mechanism underlying. Moreover, we found increased levels of myocardial C5 and the serum C5a in Des-/-C3-/- mice compared to wild-type mice, indicating that C5 is activated independently from the conventional pathway, presumably via the coagulation system. Crosstalk between the complement and coagulation systems exacerbated the myocardial injury in ARVC mice, and this injury was reduced by using the thrombin inhibitor lepirudin. In addition, we found significantly elevated plasma levels of sC5b9 and thrombin in patients, and this increase was correlated with all-cause mortality. Conclusions: These results suggest that crosstalk between the coagulation and complement systems plays a pathogenic role in cardiac dysfunction in ARVC. Thus, understanding this crosstalk may have important clinical implications with respect to diagnosing and treating ARVC.

Chronic Empagliflozin Treatment Reduces Myocardial Infarct Size in Nondiabetic Mice Through STAT-3-Mediated Protection on Microvascular Endothelial Cells and Reduction of Oxidative Stress

Aims: Empagliflozin (EMPA) demonstrates cardioprotective effects on diabetic myocardium but its infarct-sparing effects in normoglycemia remain unspecified. We investigated the acute and chronic effect of EMPA on infarct size after ischemia-reperfusion (I/R) injury and the mechanisms of cardioprotection in nondiabetic mice. Results: Chronic oral administration of EMPA (6 weeks) reduced myocardial infarct size after 30 min/2 h I/R (26.5% ± 3.9% vs 45.8% ± 3.3% in the control group, p < 0.01). Body weight, blood pressure, glucose levels, and cardiac function remained unchanged between groups. Acute administration of EMPA 24 or 4 h before I/R did not affect infarct size. Chronic EMPA treatment led to a significant reduction of oxidative stress biomarkers. STAT-3 (signal transducer and activator of transcription 3) was activated by Y(705) phosphorylation at the 10th minute of R, but it remained unchanged at 2 h of R and in the acute administration protocols. Proteomic analysis was employed to investigate signaling intermediates and revealed that chronic EMPA treatment regulates several pathways at reperfusion, including oxidative stress and integrin-related proteins that were further evaluated. Superoxide dismutase and vascular endothelial growth factor were increased throughout reperfusion. EMPA pretreatment (24 h) increased the viability of human microvascular endothelial cells in normoxia and on 3 h hypoxia/1 h reoxygenation and reduced reactive oxygen species production. In EMPA-treated murine hearts, CD31-/VEGFR2-positive endothelial cells and the pSTAT-3(Y705) signal derived from endothelial cells were boosted at early reperfusion. Innovation: Chronic EMPA administration reduces infarct size in healthy mice via the STAT-3 pathway and increases the survival of endothelial cells. Conclusion: Chronic but not acute administration of EMPA reduces infarct size through STAT-3 activation independently of diabetes mellitus.

Comprehensive multicomponent cardiac rehabilitation in cardiac implantable electronic devices recipients: a consensus document from the European Association of Preventive Cardiology (EAPC; Secondary prevention and rehabilitation section) and European Heart Rhythm Association (EHRA)

Cardiac rehabilitation (CR) is a multidisciplinary intervention including patient assessment and medical actions to promote stabilization, management of cardiovascular risk factors, vocational support, psychosocial management, physical activity counselling, and prescription of exercise training. Millions of people with cardiac implantable electronic devices live in Europe and their numbers are progressively increasing, therefore, large subsets of patients admitted in CR facilities have a cardiac implantable electronic device. Patients who are cardiac implantable electronic devices recipients are considered eligible for a CR programme. This is not only related to the underlying heart disease but also to specific issues, such as psychological adaptation to living with an implanted device and, in implantable cardioverter-defibrillator patients, the risk of arrhythmia, syncope, and sudden cardiac death. Therefore, these patients should receive special attention, as their needs may differ from other patients participating in CR. As evidence from studies of CR in patients with cardiac implantable electronic devices is sparse, detailed clinical practice guidelines are lacking. Here, we aim to provide practical recommendations for CR in cardiac implantable electronic devices recipients in order to increase CR implementation, efficacy, and safety in this subset of patients.

Exercise-based cardiac rehabilitation for chronic heart failure: the EXTRAMATCH II individual participant data meta-analysis

BACKGROUND

Current national and international guidelines on the management of heart failure (HF) recommend exercise-based cardiac rehabilitation (ExCR), but do not differentiate this recommendation according to patient subgroups.

OBJECTIVES

(1) To obtain definitive estimates of the impact of ExCR interventions compared with no exercise intervention (control) on mortality, hospitalisation, exercise capacity and health-related quality of life (HRQoL) in HF patients; (2) to determine the differential (subgroup) effects of ExCR in HF patients according to their age, sex, left ventricular ejection fraction, HF aetiology, New York Heart Association class and baseline exercise capacity; and (3) to assess whether or not the change in exercise capacity mediates for the impact of the ExCR on final outcomes (mortality, hospitalisation and HRQoL), and determine if this is an acceptable surrogate end point.

DESIGN

This was an individual participant data (IPD) meta-analysis.

SETTING

An international literature review.

PARTICIPANTS

HF patients in randomised controlled trials (RCTs) of ExCR.

INTERVENTIONS

ExCR for at least 3 weeks compared with a no-exercise control, with 6 months' follow-up.

MAIN OUTCOME MEASURES

All-cause and HF-specific mortality, all-cause and HF-specific hospitalisation, exercise capacity and HRQoL.

DATA SOURCES

IPD from eligible RCTs.

REVIEW METHODS

RCTs from the Exercise Training Meta-Analysis of Trials for Chronic Heart Failure (ExTraMATCH/ExTraMATCH II) IPD meta-analysis and a 2014 Cochrane systematic review of ExCR (Taylor RS, Sagar VA, Davies EJ, Briscoe S, Coats AJ, Dalal H, et al. Exercise-based rehabilitation for heart failure. Cochrane Database Syst Rev 2014;4:CD003331).

RESULTS

Out of the 23 eligible RCTs (4398 patients), 19 RCTs (3990 patients) contributed data to this IPD meta-analysis. There was a wide variation in exercise programme prescriptions across included studies. Compared with control, there was no statistically significant difference in pooled time-to-event estimates in favour of ExCR, although confidence intervals (CIs) were wide: all-cause mortality had a hazard ratio (HR) of 0.83 (95% CI 0.67 to 1.04); HF-related mortality had a HR of 0.84 (95% CI 0.49 to 1.46); all-cause hospitalisation had a HR of 0.90 (95% CI 0.76 to 1.06); and HF-related hospitalisation had a HR of 0.98 (95% CI 0.72 to 1.35). There was a statistically significant difference in favour of ExCR for exercise capacity and HRQoL. Compared with the control, improvements were seen in the 6-minute walk test (6MWT) (mean 21.0 m, 95% CI 1.57 to 40.4 m) and Minnesota Living with Heart Failure Questionnaire score (mean -5.94, 95% CI -1.0 to -10.9; lower scores indicate improved HRQoL) at 12 months' follow-up. No strong evidence for differential intervention effects across patient characteristics was found for any outcomes. Moderate to good levels of correlation (R ² _trial > 50% and p > 0.50) between peak oxygen uptake (VO₂peak) or the 6MWT with mortality and HRQoL were seen. The estimated surrogate threshold effect was an increase of 1.6 to 4.6 ml/kg/minute for VO₂peak.

LIMITATIONS

There was a lack of consistency in how included RCTs defined and collected the outcomes: it was not possible to obtain IPD from all includable trials for all outcomes and patient-level data on exercise adherence was not sought.

CONCLUSIONS

In comparison with the no-exercise control, participation in ExCR improved the exercise and HRQoL in HF patients, but appeared to have no effect on their mortality or hospitalisation. No strong evidence was found of differential intervention effects of ExCR across patient characteristics. VO₂peak and 6MWT may be suitable surrogate end points for the treatment effect of ExCR on mortality and HRQoL in HF. Future studies should aim to achieve a consensus on the definition of outcomes and promote reporting of a core set of HF data. The research team also seeks to extend current policies to encourage study authors to allow access to RCT data for the purpose of meta-analysis.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014007170.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Desmin is essential for the structure and function of the sinoatrial node: implications for increased arrhythmogenesis

Our objective was to investigate the effect of desmin depletion on the structure and function of the sinoatrial pacemaker complex (SANcl) and its implication in arrhythmogenesis. Analysis of mice and humans (SANcl) indicated that the sinoatrial node exhibits high amounts of desmin, desmoplakin, N-cadherin, and β-catenin in structures we call "lateral intercalated disks" connecting myocytes side by side. Examination of the SANcl from an arrhythmogenic cardiomyopathy model, desmin-deficient (Des^-/-) mouse, by immunofluorescence, ultrastructural, and Western blot analysis showed that the number of these lateral intercalated disks was diminished. Also, electrophysiological recordings of the isolated compact sinoatrial node revealed increased pacemaker systolic potential and higher diastolic depolarization rate compared with wild-type mice. Prolonged interatrial conduction expressed as a longer P wave duration was also observed in Des^-/- mice. Upregulation of mRNA levels of both T-type Ca²⁺ current channels, Cav3.1 and Cav3.2, in the Des^-/- myocardium (1.8- and 2.3-fold, respectively) and a 1.9-fold reduction of funny hyperpolarization-activated cyclic nucleotide-gated K⁺ channel 1 could underlie these functional differences. To investigate arrhythmogenicity, electrocardiographic analysis of Des-deficient mice revealed a major increase in supraventricular and ventricular ectopic beats compared with wild-type mice. Heart rate variability analysis indicated a sympathetic predominance in Des^-/- mice, which may further contribute to arrhythmogenicity. In conclusion, our results indicate that desmin elimination leads to structural and functional abnormalities of the SANcl. These alterations may be enhanced by the sympathetic component of the cardiac autonomic nervous system, which is predominant in the desmin-deficient heart, thus leading to increased arrhythmogenesis.NEW & NOTEWORTHY The sinoatrial node exhibits high amounts of desmin and desmoplakin in structures we call "lateral intercalated disks," connecting side-by-side adjacent cardiomyocytes. These structures are diminished in desmin-deficient mouse models. Misregulation of T-type Ca²⁺ current and hyperpolarization-activated cyclic nucleotide-gated K⁺ channel 1 was proved along with prolonged interatrial conduction and cardiac autonomic nervous system dysfunction.

Standardization and quality improvement of secondary prevention through cardiovascular rehabilitation programmes in Europe: The avenue towards EAPC accreditation programme: A position statement of the Secondary Prevention and Rehabilitation Section of the European Association of Preventive Cardiology (EAPC)

Despite the proven efficacy and cost-effectiveness of contemporary cardiovascular rehabilitation programmes, the referral to/uptake of and adherence to cardiovascular rehabilitation remains inadequate. In addition, heterogeneity persists amongst different cardiovascular rehabilitation centres in Europe, despite the available scientific documents describing the evidence-based rehabilitation format/content. This position statement was elaborated by the Secondary Prevention and Rehabilitation (SP/CR) section of EAPC. It defines the minimal and optimal cardiovascular rehabilitation standards. In addition, it describes the relevant quality indicators of cardiovascular rehabilitation programmes to date. Compliance of European cardiovascular rehabilitation centres with these standards will improve cardiovascular rehabilitation process standardization in Europe and hence increase the quality of cadiovascular rehabilitation programmes.

Secondary prevention through comprehensive cardiovascular rehabilitation: From knowledge to implementation. 2020 update. A position paper from the Secondary Prevention and Rehabilitation Section of the European Association of Preventive Cardiology

Secondary prevention through comprehensive cardiac rehabilitation has been recognized as the most cost-effective intervention to ensure favourable outcomes across a wide spectrum of cardiovascular disease, reducing cardiovascular mortality, morbidity and disability, and to increase quality of life. The delivery of a comprehensive and 'modern' cardiac rehabilitation programme is mandatory both in the residential and the out-patient setting to ensure expected outcomes. The present position paper aims to update the practical recommendations on the core components and goals of cardiac rehabilitation intervention in different cardiovascular conditions, in order to assist the whole cardiac rehabilitation staff in the design and development of the programmes, and to support healthcare providers, insurers, policy makers and patients in the recognition of the positive nature of cardiac rehabilitation. Starting from the previous position paper published in 2010, this updated document maintains a disease-oriented approach, presenting both well-established and more controversial aspects. Particularly for implementation of the exercise programme, advances in different training modalities were added and new challenging populations were considered. A general table applicable to all cardiovascular conditions and specific tables for each clinical condition have been created for routine practice.

Effectiveness of comprehensive cardiac rehabilitation in coronary artery disease patients treated according to contemporary evidence based medicine: Update of the Cardiac Rehabilitation Outcome Study (CROS-II)

Background

Despite numerous studies and meta-analyses the prognostic effect of cardiac rehabilitation is still under debate. This update of the Cardiac Rehabilitation Outcome Study (CROS II) provides a contemporary and practice focused approach including only cardiac rehabilitation interventions based on published standards and core components to evaluate cardiac rehabilitation delivery and effectiveness in improving patient prognosis.

Design

A systematic review and meta-analysis.

Methods

Randomised controlled trials and retrospective and prospective controlled cohort studies evaluating patients after acute coronary syndrome, coronary artery bypass grafting or mixed populations with coronary artery disease published until September 2018 were included.

Results

Based on CROS inclusion criteria out of 7096 abstracts six additional studies including 8671 patients were identified (two randomised controlled trials, two retrospective controlled cohort studies, two prospective controlled cohort studies). In total, 31 studies including 228,337 patients were available for this meta-analysis (three randomised controlled trials, nine prospective controlled cohort studies, 19 retrospective controlled cohort studies; 50,653 patients after acute coronary syndrome 14,583, after coronary artery bypass grafting 163,101, mixed coronary artery disease populations; follow-up periods ranging from 9 months to 14 years). Heterogeneity in design, cardiac rehabilitation delivery, biometrical assessment and potential confounders was considerable. Controlled cohort studies showed a significantly reduced total mortality (primary endpoint) after cardiac rehabilitation participation in patients after acute coronary syndrome (prospective controlled cohort studies: hazard ratio (HR) 0.37, 95% confidence interval (CI) 0.20–0.69; retrospective controlled cohort studies HR 0.64, 95% CI 0.53–0.76; prospective controlled cohort studies odds ratio 0.20, 95% CI 0.08–0.48), but the single randomised controlled trial fulfilling the CROS inclusion criteria showed neutral results. Cardiac rehabilitation participation was also associated with reduced total mortality in patients after coronary artery bypass grafting (retrospective controlled cohort studies HR 0.62, 95% CI 0.54–0.70, one single randomised controlled trial without fatal events), and in mixed coronary artery disease populations (retrospective controlled cohort studies HR 0.52, 95% CI 0.36–0.77; two out of 10 controlled cohort studies with neutral results).

Conclusion

CROS II confirms the effectiveness of cardiac rehabilitation participation after acute coronary syndrome and after coronary artery bypass grafting in actual clinical practice by reducing total mortality under the conditions of current evidence-based coronary artery disease treatment. The data of CROS II, however, underscore the urgent need to define internationally accepted minimal standards for cardiac rehabilitation delivery as well as for scientific evaluation.

Cardiovascular phenotype of mice lacking 3-mercaptopyruvate sulfurtransferase

RATIONALE

Hydrogen sulfide (H₂S) is a physiological mediator that regulates cardiovascular homeostasis. Three major enzymes contribute to the generation of endogenously produced H₂S, namely cystathionine γ-lyase (CSE), cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (3-MST). Although the biological roles of CSE and CBS have been extensively investigated in the cardiovascular system, very little is known about that of 3-MST. In the present study we determined the importance of 3-MST in the heart and blood vessels, using a genetic model with a global 3-MST deletion.

RESULTS

3-MST is the most abundant transcript in the mouse heart, compared to CSE and CBS. 3-MST was mainly localized in smooth muscle cells and cardiomyocytes, where it was present in both the mitochondria and the cytosol. Levels of serum and cardiac H₂S species were not altered in adult young (2-3 months old) 3-MST^-/- mice compared to WT animals. No significant changes in the expression of CSE and CBS were observed. Additionally, 3-MST^-/- mice had normal left ventricular structure and function, blood pressure and vascular reactivity. Interestingly, genetic ablation of 3-MST protected mice against myocardial ischemia reperfusion injury, and abolished the protection offered by ischemic pre- and post-conditioning. 3-MST^-/- mice showed lower expression levels of thiosulfate sulfurtransferase, lower levels of cellular antioxidants and elevated basal levels of cardiac reactive oxygen species. In parallel, 3-MST^-/- mice showed no significant alterations in endothelial NO synthase or downstream targets. Finally, in a separate cohort of older 3-MST^-/- mice (18 months old), a hypertensive phenotype associated with cardiac hypertrophy and NO insufficiency was observed.

CONCLUSIONS

Overall, genetic ablation of 3-MST impacts on the mouse cardiovascular system in an age-dependent manner. Loss of 3-MST exerts a cardioprotective role in young adult mice, while with aging it predisposes them to hypertension and cardiac hypertrophy.

Impact of Exercise Rehabilitation on Exercise Capacity and Quality-of-Life in Heart Failure: Individual Participant Meta-Analysis

BACKGROUND

Previous systematic reviews have indicated that exercise-based cardiac rehabilitation (ExCR) for patients with heart failure (HF) has a beneficial effect on health-related quality-of-life (HRQoL) and exercise capacity. However, there is uncertainty regarding potential differential effects of ExCR across HF patient subgroups.

OBJECTIVES

The authors sought to undertake an individual participant data (IPD) meta-analysis to: 1) assess the impact of ExCR on HRQoL and exercise capacity in patients with HF; and 2) investigate differential effects of ExCR according to a range of patient characteristics: age, sex, ethnicity, New York Heart Association functional class, ischemic etiology, ejection fraction, and exercise capacity.

METHODS

A single dataset was produced, comprising randomized trials where ExCR (delivered for 3 weeks or more) was compared with a no exercise control group. Each trial provided IPD on HRQoL or exercise capacity (or both), with follow-up of 6 months or more. One- and 2-stage meta-analysis models were used to investigate the effect of ExCR overall and the interactions between ExCR and participant characteristics.

RESULTS

IPD was obtained from 13 trials for 3,990 patients, predominantly (97%) with reduced ejection fraction HF. Compared with the control group, there was a statistically significant difference in favor of ExCR for HRQoL and exercise capacity. At 12-month follow-up, improvements were seen in 6-min walk test (mean 21.0 m; 95% confidence interval: 1.57 to 40.4 m; p = 0.034) and Minnesota Living With HF score (mean improvement 5.9; 95% confidence interval: 1.0 to 10.9; p = 0.018). No consistent evidence was found of differential intervention effects across patient subgroups.

CONCLUSIONS

These results, based on an IPD meta-analysis of randomized trials, confirm the benefit of ExCR on HRQoL and exercise capacity and support the Class I recommendation of current international clinical guidelines that ExCR should be offered to all HF patients. (Exercise Training for Chronic Heart Failure [ExTraMATCH II]: protocol for an individual participant data meta-analysis; PROSPERO: international database of systematic reviews CRD42014007170).

Impact of exercise-based cardiac rehabilitation in patients with heart failure (ExTraMATCH II) on mortality and hospitalisation: an individual patient data meta-analysis of randomised trials

AIMS

To undertake an individual patient data (IPD) meta-analysis to assess the impact of exercise-based cardiac rehabilitation (ExCR) in patients with heart failure (HF) on mortality and hospitalisation, and differential effects of ExCR according to patient characteristics: age, sex, ethnicity, New York Heart Association functional class, ischaemic aetiology, ejection fraction, and exercise capacity.

METHODS AND RESULTS

Randomised trials of exercise training for at least 3 weeks compared with no exercise control with 6-month follow-up or longer, providing IPD time to event on mortality or hospitalisation (all-cause or HF-specific). IPD were combined into a single dataset. We used Cox proportional hazards models to investigate the effect of ExCR and the interactions between ExCR and participant characteristics. We used both two-stage random effects and one-stage fixed effect models. IPD were obtained from 18 trials including 3912 patients with HF with reduced ejection fraction. Compared to control, there was no statistically significant difference in pooled time to event estimates in favour of ExCR although confidence intervals (CIs) were wide [all-cause mortality: hazard ratio (HR) 0.83, 95% CI 0.67-1.04; HF-specific mortality: HR 0.84, 95% CI 0.49-1.46; all-cause hospitalisation: HR 0.90, 95% CI 0.76-1.06; and HF-specific hospitalisation: HR 0.98, 95% CI 0.72-1.35]. No strong evidence was found of differential intervention effects across patient characteristics.

CONCLUSION

Exercise-based cardiac rehabilitation did not have a significant effect on the risk of mortality and hospitalisation in HF with reduced ejection fraction. However, uncertainty around effect estimates precludes drawing definitive conclusions.

Amelioration of desmin network defects by αB-crystallin overexpression confers cardioprotection in a mouse model of dilated cardiomyopathy caused by LMNA gene mutation

The link between the cytoplasmic desmin intermediate filaments and those of nuclear lamins serves as a major integrator point for the intracellular communication between the nucleus and the cytoplasm in cardiac muscle. We investigated the involvement of desmin in the cardiomyopathy caused by the lamin A/C gene mutation using the Lmna^H222P/H222P mouse model of the disease. We demonstrate that in these mouse hearts desmin loses its normal Z disk and intercalated disc localization and presents aggregate formation along with mislocalization of basic intercalated disc protein components, as well as severe structural abnormalities of the intercalated discs and mitochondria. To address the extent by which the observed desmin network defects contribute to the progression of Lmna^H222P/H222P cardiomyopathy, we investigated the consequences of desmin-targeted approaches for the disease treatment. We showed that cardiac-specific overexpression of the small heat shock protein αΒ-Crystallin confers cardioprotection in Lmna^H222P/H222P mice by ameliorating desmin network defects and by attenuating the desmin-dependent mislocalization of basic intercalated disc protein components. In addition, αΒ-Crystallin overexpression rescues the intercalated disc, mitochondrial and nuclear defects of Lmna^H222P/H222P hearts, as well as the abnormal activation of ERK1/2. Consistent with that, by generating the Lmna^H222P/H222PDes+/- mice, we showed that the genetically decreased endogenous desmin levels have cardioprotective effects in Lmna^H222P/H222P hearts since less desmin is available to form dysfunctional aggregates. In conclusion, our results demonstrate that desmin network disruption, disorganization of intercalated discs and mitochondrial defects are a major mechanism contributing to the progression of this LMNA cardiomyopathy and can be ameliorated by αΒ-Crystallin overexpression.

Impaired calcium homeostasis is associated with sudden cardiac death and arrhythmias in a genetic equivalent mouse model of the human HRC-Ser96Ala variant

Aims

The histidine-rich calcium-binding protein (HRC) Ser96Ala variant has previously been identified as a potential biomarker for ventricular arrhythmias and sudden cardiac death in patients with idiopathic dilated cardiomyopathy. Herein, the role of this variant in cardiac pathophysiology is delineated through a novel mouse model, carrying the human mutation in the homologous mouse position.

Methods and results

The mouse HRC serine 81, homologous to human HRC serine 96, was mutated to alanine, using knock-in gene targeting. The HRC-Ser81Ala mice presented increased mortality in the absence of structural or histological abnormalities, indicating that early death may be arrhythmia-related. Indeed, under stress-but not baseline-conditions, the HRC-Ser81Ala mice developed ventricular arrhythmias, whilst at the cardiomyocyte level they exhibited increased occurrence of triggered activity. Cardiac contraction was decreased in vivo, ex vivo, and in vitro. Additionally, Ca2+ transients and SR Ca2+ load were both reduced suggesting that cytosolic Ca2+ overload is not the underlying proarrhythmic mechanism. Interestingly, total SR Ca2+ leak was increased in HRC-Ser81Ala cardiomyocytes, without an increase in Ca2+ spark and wave frequency. However, Ca2+ wave propagation was significantly slower and the duration of the associated Na/Ca exchange current was increased. Moreover, action potential duration was also increased. Notably, Ca2+/Calmodulin kinase II (CaMKII) phosphorylation of the ryanodine receptor was increased, whilst KN-93, an inhibitor of CaMKII, reduced the occurrence of arrhythmias.

Conclusions

The homologous mutation Ser81Ala in HRC in mice, corresponding to Ser96Ala in humans, is associated with sudden death and depressed cardiac function. Ventricular arrhythmias are related to abnormal Ca2+ cycling across the SR. The data further support a role for CaMKII with the perspective to treat arrhythmias through CaMKII inhibition.

Targeting of the breast cancer microenvironment with a potent and linkable oxindole based antiangiogenic small molecule

The clinical efficacy of antiangiogenic small molecules (e.g., sunitinib) in breast carcinoma has largely failed with substantial off-target toxicity. We rationally designed and evaluated preclinically a novel sunitinib analogue, SAP, with favourable pharmacological properties and the ability to be readily conjugated to a targeting peptide or antibody for active tumour targeting.

SAP was evaluated in silico and in vitro in order to verify target engagement (e.g., VEGFR2). Pharmacokinetic and biodistribution parameters were determined in mice using LC-MS/MS. SAP efficacy was tested in two breast cancer xenograft and two syngeneic animal models and pharmacodynamic evaluation was accomplished using phosphokinase assays and immunohistochemistry. Cardiac and blood toxicity of SAP were also monitored.

SAP retained the antiangiogenic and cytotoxic properties of the parental molecule with an increased blood exposure and tumor accumulation compared to sunitinib. SAP proved efficacious in all animal models. Tumors from SAP treated animals had significantly decreased Ki-67 and CD31 markers and reduced levels of phosphorylated AKT, ERK and S6 compared to vehicle treated animals. In mice dosed with SAP there was negligible hematotoxicity, while cardiac function measurements showed a reduction in the percentage left ventricular fractional shortening compared to vehicle treated animals.

In conclusion, SAP is a novel rationally designed conjugatable small antiangiogenic molecule, efficacious in preclinical models of breast cancer.

Empagliflozin Limits Myocardial Infarction in Vivo and Cell Death in Vitro: Role of STAT3, Mitochondria, and Redox Aspects

Empagliflozin (EMPA), a drug approved for type 2 diabetes management, reduced cardiovascular death but is unknown if it reduces myocardial infarction. We sought to investigate: (i) the effect of EMPA on myocardial function and infarct size after ischemia/reperfusion in mice fed with western diet (WD), (ii) the underlying signaling pathways, (iii) its effects on cell survival in rat embryonic-heart-derived cardiomyoblasts (H9C2) and endothelial cells (ECs). To facilitate the aforementioned aims, mice were initially randomized in Control and EMPA groups and were subjected to 30 min ischemia and 2 h reperfusion. EMPA reduced body weight, blood glucose levels, and mean arterial pressure. Cholesterol, triglyceride, and AGEs remained unchanged. Left ventricular fractional shortening was improved (43.97 ± 0.92 vs. 40.75 ± 0.61%) and infarct size reduced (33.2 ± 0.01 vs. 17.6 ± 0.02%). In a second series of experiments, mice were subjected to the above interventions up to the 10th min of reperfusion and myocardial biopsies were obtained for assessment of the signaling cascade. STAT3 was increased in parallel with reduced levels of malondialdehyde (MDA) and reduced expression of myocardial iNOS and interleukin-6. Cell viability and ATP content were increased in H9C2 and in ECs. While, STAT3 phosphorylation is known to bestow infarct sparing properties through interaction with mitochondria, we observed that EMPA did not directly alter the mitochondrial calcium retention capacity (CRC); therefore, its effect in reducing myocardial infarction is STAT3 dependent. In conclusion, EMPA improves myocardial function and reduces infarct size as well as improves redox regulation by decreasing iNOS expression and subsequently lipid peroxidation as shown by its surrogate marker MDA. The mechanisms of action implicate the activation of STAT3 anti-oxidant and anti-inflammatory properties.