Reverse remodelling and myocardial recovery in heart failure

The Roles of Noncardiomyocytes in Cardiac Remodeling

Cardiac remodeling is a common characteristic of almost all forms of heart disease, including cardiac infarction, valvular diseases, hypertension, arrhythmia, dilated cardiomyopathy and other conditions. It is not merely a simple outcome induced by an increase in the workload of cardiomyocytes (CMs). The remodeling process is accompanied by abnormalities of cardiac structure as well as disturbance of cardiac function, and emerging evidence suggests that a wide range of cells in the heart participate in the initiation and development of cardiac remodeling. Other than CMs, there are numerous noncardiomyocytes (non-CMs) that regulate the process of cardiac remodeling, such as cardiac fibroblasts and immune cells (including macrophages, lymphocytes, neutrophils, and mast cells). In this review, we summarize recent knowledge regarding the definition and significant effects of various non-CMs in the pathogenesis of cardiac remodeling, with a particular emphasis on the involved signaling mechanisms. In addition, we discuss the properties of non-CMs, which serve as targets of many cardiovascular drugs that reduce adverse cardiac remodeling.

Upregulation of long non-coding RNA MEG3 in type 2 diabetes mellitus complicated with vascular disease: a case-control study

Previous studies have indicated that long non-coding RNAs (lncRNAs) were closely related to diabetes. In this study, we aimed to explore the possible role and mechanism of lncRNA MEG3 in the occurrence and development of type 2 diabetes mellitus (T2DM) and its vascular complications. A case-control study involving 115 subjects was conducted, including 53 T2DM patients (37 patients with vascular complication and 16 patients without vascular complications) and 62 healthy subjects. We performed real-time polymerase chain reaction (RT-PCR) analysis of the lncRNA MEG3 and miR-146a levels in peripheral blood mononuclear cells (PBMCs) in the 115 samples. We found that the expression of lncRNA MEG3 was upregulated in the T2DM patients with vascular complication (DC group) compared with T2DM patients without vascular complication (D group) (P < 0.05) and the control group (P < 0.01). miR-146a levels in DC group were significantly lower compared with control group. There was a significant positive correlation between the expression of lncRNA MEG3 and glucose (GLU) (r = 0.301, P = 0.0011) and hemoglobin A1C (HbA1c) (r = 0.477, P = 0.0006). Our study suggests MEG3 may play as an important role in progression of diabetes-related vascular complications, contributing to a novel understanding of pathogenesis and prognosis for diabetes and its complications.

Core functional nodes and sex-specific pathways in human ischaemic and dilated cardiomyopathy

Poor access to human left ventricular myocardium is a significant limitation in the study of heart failure (HF). Here, we utilise a carefully procured large human heart biobank of cryopreserved left ventricular myocardium to obtain direct molecular insights into ischaemic cardiomyopathy (ICM) and dilated cardiomyopathy (DCM), the most common causes of HF worldwide. We perform unbiased, deep proteomic and metabolomic analyses of 51 left ventricular (LV) samples from 44 cryopreserved human ICM and DCM hearts, compared to age-, gender-, and BMI-matched, histopathologically normal, donor controls. We report a dramatic reduction in serum amyloid A1 protein in ICM hearts, perturbed thyroid hormone signalling pathways and significant reductions in oxidoreductase co-factor riboflavin-5-monophosphate and glycolytic intermediate fructose-6-phosphate in both; unveil gender-specific changes in HF, including nitric oxide-related arginine metabolism, mitochondrial substrates, and X chromosome-linked protein and metabolite changes; and provide an interactive online application as a publicly-available resource.

Computational modeling of cardiac growth and remodeling in pressure overloaded hearts-Linking microstructure to organ phenotype

Cardiac growth and remodeling (G&R) refers to structural changes in myocardial tissue in response to chronic alterations in loading conditions. One such condition is pressure overload where elevated wall stresses stimulate the growth in cardiomyocyte thickness, associated with a phenotype of concentric hypertrophy at the organ scale, and promote fibrosis. The initial hypertrophic response can be considered adaptive and beneficial by favoring myocyte survival, but over time if pressure overload conditions persist, maladaptive mechanisms favoring cell death and fibrosis start to dominate, ultimately mediating the transition towards an overt heart failure phenotype. The underlying mechanisms linking biological factors at the myocyte level to biomechanical factors at the systemic and organ level remain poorly understood. Computational models of G&R show high promise as a unique framework for providing a quantitative link between myocardial stresses and strains at the organ scale to biological regulatory processes at the cellular level which govern the hypertrophic response. However, microstructurally motivated, rigorously validated computational models of G&R are still in their infancy. This article provides an overview of the current state-of-the-art of computational models to study cardiac G&R. The microstructure and mechanosensing/mechanotransduction within cells of the myocardium is discussed and quantitative data from previous experimental and clinical studies is summarized. We conclude with a discussion of major challenges and possible directions of future research that can advance the current state of cardiac G&R computational modeling. STATEMENT OF SIGNIFICANCE: The mechanistic links between organ-scale biomechanics and biological factors at the cellular size scale remain poorly understood as these are largely elusive to investigations using experimental methodology alone. Computational G&R models show high promise to establish quantitative links which allow more mechanistic insight into adaptation mechanisms and may be used as a tool for stratifying the state and predict the progression of disease in the clinic. This review provides a comprehensive overview of research in this domain including a summary of experimental data. Thus, this study may serve as a basis for the further development of more advanced G&R models which are suitable for making clinical predictions on disease progression or for testing hypotheses on pathogenic mechanisms using in-silico models.

Sacubitril/Valsartan Improves Left Ventricular Ejection Fraction and Reverses Cardiac Remodeling in Taiwanese Patients with Heart Failure and Reduced Ejection Fraction

Background

The angiotensin receptor-neprilysin inhibitor sacubitril/valsartan is known to improve outcomes of cardiac death and hospitalization due to heart failure in patients with heart failure and reduced ejection fraction (HFrEF). However, data on improvements in ejection fraction after using sacubitril/valsartan are still lacking in Taiwan.

Methods

We conducted this prospective, single armed, observation cohort study to evaluate changes in left ventricular ejection fraction (LVEF) in patients with heart failure and reduced LVEF treated with sacubitril/valsartan. This was an all-comer study. We prescribed sacubitril/valsartan as both first-line and second-line therapy to every eligible patient regardless of whether they were already on standard therapy or newly-diagnosed with HFrEF. The primary outcome was improvements in LVEF. We also collected data about changes in left ventricular chamber size, blood pressure, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and renal function according to serum creatinine level.

Results

During March 2016 to April 2018, 93 patients were enrolled. The mean LVEF improved from 35 ± 6.1% to 50 ± 8.8% at 6 months use of sacubitril/valsartan (p < 0.001). The left ventricular end-diastolic diameter, left ventricular end-systolic diameter, and left atrial diameter all decreased. The average NT-proBNP level decreased from 6379 pg/mL to 1661 pg/dL.

Conclusions

Sacubitril/valsartan demonstrated a significant effect in improving LVEF, left ventricular reverse remodeling, and reduction of NT-proBNP in this Taiwanese cohort.

Development of Injectable Amniotic Membrane Matrix for Postmyocardial Infarction Tissue Repair

Ischemic heart disease represents the leading cause of death worldwide. Heart failure following myocardial infarction (MI) is associated with severe fibrosis formation and cardiac remodeling. Recently, injectable hydrogels have emerged as a promising approach to repair the infarcted heart and improve heart function through minimally invasive administration. Here, a novel injectable human amniotic membrane (hAM) matrix is developed to enhance cardiac regeneration following MI. Human amniotic membrane is isolated from human placenta and engineered to be a thermoresponsive, injectable gel around body temperature. Ultrasound-guided injection of hAM matrix into rat MI hearts significantly improves cardiac contractility, as measured by ejection fraction (EF), and decrease fibrosis. The results of this study demonstrate the feasibility of engineering as an injectable hAM matrix and its efficacy in attenuating degenerative changes in cardiac function following MI, which may have broad applications in tissue regeneration.

Comprehensive Analysis and Co-Expression Network of mRNAs and lncRNAs in Pressure Overload-Induced Heart Failure

Aim: Heart failure (HF) is the end stage of various cardiovascular diseases. However, the precise regulation of gene expression profiles and functional mechanisms of long non-coding RNAs (lncRNAs) in HF remain to be elucidated. The present study aimed to identify the differentially expressed profiles and interaction of messenger RNAs (mRNAs) and lncRNAs in pressure overload-induced HF.

Methods: Male Sprague-Dawley rats were randomly divided into the HF group and the sham-operated group. HF was induced by the transverse aortic constriction (TAC) surgery. The cardiac expression profiles of mRNAs and lncRNAs in HF were investigated using the microarray. Bioinformatics analyses and co-expression network construction were performed from the RNA sequencing data.

Results: The expression profiles of mRNAs and lncRNAs showed significant differences between HF and controls. A total of 147 mRNAs and 162 lncRNAs were identified to be differentially expressed with a fold change of >2 in HF. The relative expression levels of several selected mRNAs and lncRNAs were validated by quantitative PCR. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses indicated that diverse pathways were involved in the molecular mechanisms of cardiac hypertrophy and HF including immune response, smooth muscle contraction, ion transmembrane transport. The mRNA-lncRNA and transcription factors (TFs)-lncRNA co-expression networks were constructed and several genes and TFs were identified as key regulators in the pathogenesis of HF. Further functional prediction showed that the lncRNA NONRATT013999 was predicted to cis-regulate mRNA CDH11, and NONRATT027756 was predicted to trans-regulate HCN4.

Conclusion: This study revealed specific expression regulation and potential functions of mRNAs and lncRNAs in pressure overload-induced HF. These results will provide new insights into the underlying mechanisms and potential therapeutic targets for HF.

The expanding role of implantable devices to monitor heart failure and pulmonary hypertension

The epidemics of heart failure and, to a lesser extent, of pulmonary arterial hypertension continue unabated worldwide and are extremely costly in terms of loss of life and earnings, as well as the burden of health-care expenditure due to repeated hospitalization. The effectiveness of newly discovered therapies for the two conditions depends on their timely application. To date, symptoms have been used to guide the application and timing of therapy. Compelling evidence now exists that symptoms are preceded by several metabolic and haemodynamic changes, particularly a rise in intravascular pressures during exercise. These observations have stimulated the development of several implantable devices for the detection of impending unstable heart failure or pulmonary arterial hypertension, necessitating admission to hospital. In this Review, we summarize the rationale for monitoring patients with heart failure or pulmonary arterial hypertension, the transition from noninvasive to implantable devices and the current and anticipated clinical uses of these devices.

Ventricular remodeling in ischemic heart failure stratifies responders to stem cell therapy

Response to stem cell therapy in heart failure is heterogeneous, warranting a better understanding of outcome predictors. This study assessed left ventricular volume, a surrogate of disease severity, on cell therapy benefit. Small to large infarctions were induced in murine hearts to model moderate, advanced, and end‐stage ischemic cardiomyopathy. At 1 month postinfarction, cardiomyopathic cohorts with comparable left ventricular enlargement and dysfunction were randomized 1:1 to those that either received sham treatment or epicardial delivery of cardiopoietic stem cells (CP). Progressive dilation and pump failure consistently developed in sham. In comparison, CP treatment produced significant benefit at 1 month post‐therapy, albeit with an efficacy impacted by cardiomyopathic stage. Advanced ischemic cardiomyopathy was the most responsive to CP‐mediated salvage, exhibiting both structural and functional restitution, with proteome deconvolution substantiating that cell therapy reversed infarction‐induced remodeling of functional pathways. Moderate cardiomyopathy was less responsive to CP therapy, improving contractility but without reversing preexistent heart enlargement. In end‐stage disease, CP therapy showed the least benefit. This proof‐of‐concept study thus demonstrates an optimal window, or “Goldilocks principle,” of left ventricular enlargement for maximized stem cell‐based cardiac repair. Disease severity grading, prior to cell therapy, should be considered to inform regenerative medicine interventions.

Cardiac autotransplantation and ex vivo surgical repair of giant left atrium: a case presentation

BACKGROUND

Chronic Mitral Valve disease is strongly associated with Left atrial enlargement; the condition has a high mortality risk. Clinical manifestations include atrial fibrillation, pulmonary hypertension, thromboembolic events, and in cases of Giant Left Atrium (GLA) and a distorted cardiac silhouette. Full sternotomy, conventional open-heart surgery, reductive atrioplasty and atrioventricular valve repair are required to resolve symptoms. However, these procedures can be complicated due to the posterior location of the GLA and concomitant right lateral protrusion. Cardiac autotransplantation is superior under these conditions; it provides improved visual access to the posterior atrial wall and mitral valve, hence, facilitates corrective surgical procedures. We aimed to assess the clinical outcome of patients undergoing cardiac autotransplantation as the primary treatment modality to resolve GLA. Moreover, we evaluated the procedural safety profile and technical feasibility.

CASE PRESENTATION

Four patients, mean EuroSCORE II of 23.7% ± 7.7%, presented with heart failure, atrial fibrillation, left atrial diameter > 6.5 cm and a severe distorted cardiac silhouette; X-ray showed prominent right lateral protrusion. We performed cardiac autotransplantation using continuous retrograde perfusion with warm blood supplemented with glucose followed by atrioplasty, atrial plication, valve annuloplasty and valve repair on the explanted beating heart. The surgical approach reduced the left atrial area, mean reduction was - 90.71 cm² [CI95% -153.3 cm² to - 28.8 cm², p = 0.02], and normalized pulmonary arterial pressure, mean decrease - 11.25 mmHg [CI95% -15.23 mmHg to - 7.272 mmHg, p = 0.003]. 3 out of 4 patients experienced an uneventful postoperative course; 2 out of 4 patients experienced a transient return to sinus rhythm following surgery. One was operated on in 2017 and is still in good condition; two other patients survived for more than 10 years; Kaplan-Meier determined median survival is 10.5 years.

CONCLUSIONS

Cardiac autotransplantation is an elegant surgical procedure that facilitates the surgical remodelling of Giant Left Atrium. Surgical repair on the ex vivo beating heart, under continuous warm blood perfusion, is a safe procedure applicable also to high-risk patients.

Meta-analysis of Exercise Training on Left Ventricular Ejection Fraction in Heart Failure with Reduced Ejection Fraction: A 10-year Update

BACKGROUND

The role of exercise training modality to attenuate left ventricular (LV) remodeling in heart failure patients with reduced ejection fraction (HFrEF) remains uncertain. The authors performed a systematic review and meta-analysis of published reports on exercise training (moderate-intensity continuous aerobic, high-intensity interval aerobic, and resistance exercise) and LV remodeling in clinically stable HFrEF patients.

METHODS

We searched MEDLINE, Cochrane Central Registry of Controlled Trials, CINAHL, and PubMed (2007 to 2017) for randomized controlled trials of exercise training on resting LV ejection fraction (EF) and end-diastolic and end-systolic volumes in HFrEF patients.

RESULTS

18 trials reported LV ejection fraction (LVEF) data, while 8 and 7 trials reported LV end-diastolic and LV end-systolic volumes, respectively. Overall, moderate-intensity continuous training (MICT) significantly increased LVEF (weighted mean difference, WMD = 3.79%; 95% confidence interval, CI, 2.08 to 5.50%) with no change in LV volumes versus control. In trials ≥6 months duration, MICT significantly improved LVEF (WMD = 6.26%; 95% CI 4.39 to 8.13%) while shorter duration (<6 months) trials modestly increased LVEF (WMD = 2.33%; 95% CI 0.84 to 3.82%). High-intensity interval training (HIIT) significantly increased LVEF compared to control (WMD = 3.70%; 95% CI 1.63 to 5.77%) but was not different than MICT (WMD = 3.17%; 95% CI -0.87 to 7.22%). Resistance training performed alone or combined with aerobic training (MICT or HIIT) did not significantly change LVEF.

CONCLUSIONS

In clinically stable HFrEF patients, MICT is an effective therapy to attenuate LV remodeling with the greatest benefits occurring with long-term (≥6 months) training. HIIT performed for 2 to 3 months is superior to control, but not MICT, for improvement of LVEF.

Mechanical Unloading in Heart Failure

Myocardial injury induces significant changes in ventricular structure and function at both the cellular and anatomic level, leading to ventricular remodeling and subsequent heart failure. Unloading left ventricular pressure has been studied in both the short-term and long-term settings, as a means of preventing or reversing cardiac remodeling. In acute myocardial infarction, cardiac unloading is used to reduce oxygen demand and limit infarct size. Research has demonstrated the benefits of short-term unloading with mechanical circulatory support devices before reperfusion in the context of acute myocardial infarction with cardiogenic shock, and a confirmatory trial is ongoing. In chronic heart failure, ventricular unloading using mechanical circulatory support can reverse many of the cellular and anatomic changes that accompany ventricular remodeling. Ongoing research is evaluating the ability of left ventricular assist devices to promote myocardial recovery and remission from clinical heart failure.

Manipulating cell fate: dynamic control of cell behaviors on functional platforms

We review the recent advances and new horizons in the dynamic control of cell behaviors on functional platforms and their applications.