Vascular dysfunction in idiopathic dilated cardiomyopathy

The predictive value of coronary microvascular dysfunction for left ventricular reverse remodelling in dilated cardiomyopathy

Aims

To evaluate the degree of coronary microvascular dysfunction (CMD) in dilated cardiomyopathy (DCM) patients by cardiac magnetic resonance (CMR) first-pass perfusion parameters and to examine the correlation between myocardial perfusion and left ventricle reverse remodelling (LVRR).

Methods

In this study, 94 DCM patients and 35 healthy controls matched for age and sex were included. Myocardial perfusion parameters, including upslope, time to maximum signal intensity (Timemax), maximum signal intensity (SImax), baseline signal intensity (SIbaseline), and the difference between maximum and baseline signal intensity (SImax-baseline) were measured. Additionally, left ventricular (LV) structure, function parameters, and late gadolinium enhancement (LGE) were also recorded. The parameters were compared between healthy controls and DCM patients. Univariable and multivariable logistic regression analyses were used to determine the predictors of LVRR.

Results

With a median follow-up period of 12 months [interquartile range (IQR), 8-13], 41 DCM patients (44%) achieved LVRR. Compared with healthy controls, DCM patients presented CMD with reduced upslope, SIbaseline, and increased Timemax (all p < 0.01). Timemax, SImax, and SImax-baseline were further decreased in LVRR than non-LVRR group (Timemax: 60.35 [IQR, 51.46-74.71] vs. 72.41 [IQR, 59.68-97.70], p = 0.017; SImax: 723.52 [IQR, 209.76-909.27] vs. 810.92 [IQR, 581.30-996.89], p = 0.049; SImax-baseline: 462.99 [IQR, 152.25-580.43] vs. 551.13 [IQR, 402.57-675.36], p = 0.038). In the analysis of multivariate logistic regression, Timemax [odds ratio (OR) 0.98; 95% confidence interval (CI) 0.95-1.00; p = 0.032)], heart rate (OR 1.04; 95% CI 1.01-1.08; p = 0.029), LV remodelling index (OR 1.73; 95% CI 1.06-3.00; p = 0.038) and LGE extent (OR 0.85; 95% CI 0.73-0.96; p = 0.021) were independent predictors of LVRR.

Conclusions

CMD could be found in DCM patients and was more impaired in patients with non-LVRR than LVRR patients. Timemax at baseline was an independent predictor of LVRR in DCM.

Insulin-like growth factor binding protein 2: a core biomarker of left ventricular dysfunction in dilated cardiomyopathy

BACKGROUND

RNA modifications, especially N6-methyladenosine, N1-methyladenosine and 5-methylcytosine, play an important role in the progression of cardiovascular disease. However, its regulatory function in dilated cardiomyopathy (DCM) remains to be undefined.

METHODS

In the study, key RNA modification regulators (RMRs) were screened by three machine learning models. Subsequently, a risk prediction model for DCM was developed and validated based on these important genes, and the diagnostic efficiency of these genes was assessed. Meanwhile, the relevance of these genes to clinical traits was explored. In both animal models and human subjects, the gene with the strongest connection was confirmed. The expression patterns of important genes were investigated using single-cell analysis.

RESULTS

A total of 4 key RMRs were identified. The risk prediction models were constructed basing on these genes which showed a good accuracy and sensitivity in both the training and test set. Correlation analysis showed that insulin-like growth factor binding protein 2 (IGFBP2) had the highest correlation with left ventricular ejection fraction (LVEF) (R = -0.49, P = 0.00039). Further validation expression level of IGFBP2 indicated that this gene was significantly upregulated in DCM animal models and patients, and correlation analysis validation showed a significant negative correlation between IGFBP2 and LVEF (R = -0.87; P = 6*10-5). Single-cell analysis revealed that this gene was mainly expressed in endothelial cells.

CONCLUSION

In conclusion, IGFBP2 is an important biomarker of left ventricular dysfunction in DCM. Future clinical applications could possibly use it as a possible therapeutic target.

Serum albumin and prognosis in elderly patients with nonischemic dilated cardiomyopathy

AIMS

Hypoalbuminemia was extensively used to diagnose malnutrition in older adults. Malnutrition was associated with mortality in elderly patients with cardiovascular diseases. The relationship between hypoalbuminemia and clinical outcomes in elderly patients with nonischemic dilated cardiomyopathy (NIDCM) remains unknown.

METHODS

A total of 1058 consecutive patients with NIDCM (age ≥60 years) were retrospectively enrolled from January 2010 to December 2019. Univariate and multivariate analyses were performed to assess the association of hypoalbuminemia with clinical outcomes.

RESULTS

Patients with hypoalbuminemia were older (69.29 ± 6.67 vs. 67.61 ± 5.90 years, P  < 0.001) and had higher prevalence of in-hospital and long-term death than those without (6.9 vs. 1.7%, 50.7 vs. 35.2%, P  < 0.001). Logistic regression analysis showed that hypoalbuminemia was significantly related to in-hospital death [odds ratio (OR): 4.334, 95% confidence interval (CI): 2.185-8.597, P  < 0.001]. Kaplan-Meier survival analysis showed that patients with hypoalbuminemia had worse prognosis than those with nonhypoalbuminemia (log-rank χ2 28.96, P  < 0.001). After adjusting for age, serum creatinine, HDL-C, AST/ALT hypoalbuminemia, LVEF and diabetes, hypoalbuminemia remained an independent predictor for long-term death (hazard ratio 1.322, 95% CI 0.046-1.670, P  = 0.019).

CONCLUSION

Hypoalbuminemia was associated with increased risk of in-hospital and long-term mortality in elderly patients with NIDCM.

From bedside to the bench: patient-specific hiPSC-EC models uncover endothelial dysfunction in genetic cardiomyopathies

Genetic cardiomyopathies are a group of inherited disorders in which myocardial structure and function are damaged. Many of these pathologies are rare and present with heterogenous phenotypes, thus personalized models are required to completely uncover their pathological mechanisms and develop valuable therapeutic strategies. Both cardiomyocytes and fibroblasts, differentiated from patient-specific human induced pluripotent stem cells, represent the most studied human cardiac cell models in the context of genetic cardiomyopathies. While endothelial dysfunction has been recognized as a possible pathogenetic mechanism, human induced pluripotent stem cell-derived endothelial cells are less studied, despite they constitute a suitable model to specifically dissect the role of the dysfunctional endothelium in the development and progression of these pathologies. In this review, we summarize the main studies in which human induced pluripotent stem cell-derived endothelial cells are used to investigate endothelial dysfunction in genetic-based cardiomyopathies to highlight new potential targets exploitable for therapeutic intervention, and we discuss novel perspectives that encourage research in this direction.

A Comprehensive Review of Dilated Cardiomyopathy in Pre-clinical Animal Models in Addition to Herbal Treatment Options and Multi-modality Imaging Strategies

Dilated cardiomyopathy (DCM) is distinguished by ventricular chamber expansion, systolic dysfunction, and normal left ventricular (LV) wall thickness, and is mainly caused due to genetic or environmental factors; however, its aetiology is undetermined in the majority of patients. The focus of this work is on pathogenesis, small animal models, as well as the herbal medicinal approach, and the most recent advances in imaging modalities for patients with dilated cardiomyopathy. Several small animal models have been proposed over the last few years to mimic various pathomechanisms that contribute to dilated cardiomyopathy. Surgical procedures, gene mutations, and drug therapies are all characteristic features of these models. The pros and cons, including heart failure stimulation of extensively established small animal models for dilated cardiomyopathy, are illustrated, as these models tend to procure key insights and contribute to the development of innovative treatment techniques for patients. Traditional medicinal plants used as treatment in these models are also discussed, along with contemporary developments in herbal therapies. In the last few decades, accurate diagnosis, proper recognition of the underlying disease, specific risk stratification, and forecasting of clinical outcome, have indeed improved the health of DCM patients. Cardiac magnetic resonance (CMR) is the bullion criterion for assessing ventricular volume and ejection fraction in a reliable and consistent direction. Other technologies, like strain analysis and 3D echocardiography, have enhanced this technique's predictive and therapeutic potential. Nuclear imaging potentially helps doctors pinpoint the causative factors of left ventricular dysfunction, as with cardiac sarcoidosis and amyloidosis.

Identification of Biomarkers Associated with Heart Failure Caused by Idiopathic Dilated Cardiomyopathy Using WGCNA and Machine Learning Algorithms

Background

The genetic factors and pathogenesis of idiopathic dilated cardiomyopathy-induced heart failure (IDCM-HF) have not been understood thoroughly; there is a lack of specific diagnostic markers and treatment methods for the disease. Hence, we aimed to identify the mechanisms of action at the molecular level and potential molecular markers for this disease.

Methods

Gene expression profiles of IDCM-HF and non-heart failure (NF) specimens were acquired from the database of Gene Expression Omnibus (GEO). We then identified the differentially expressed genes (DEGs) and analyzed their functions and related pathways by using "Metascape". Weighted gene co-expression network analysis (WGCNA) was utilized to search for key module genes. Candidate genes were identified by intersecting the key module genes identified via WGCNA with DEGs and further screened via the support vector machine-recursive feature elimination (SVM-RFE) method and the least absolute shrinkage and selection operator (LASSO) algorithm. At last, the biomarkers were validated and evaluated the diagnostic efficacy by the area under curve (AUC) value and further confirmed the differential expression in the IDCM-HF and NF groups using an external database.

Results

We detected 490 genes exhibiting differential expression between IDCM-HF and NF specimens from the GSE57338 dataset, with most of them being concentrated in the extracellular matrix (ECM) of cells related to biological processes and pathways. After screening, 13 candidate genes were identified. Aquaporin 3 (AQP3) and cytochrome P450 2J2 (CYP2J2) showed high diagnostic efficacy in the GSE57338 and GSE6406 datasets, respectively. In comparison to the NF group, AQP3 was significantly down-regulated in the IDCM-HF group, while CYP2J2 was significantly up-regulated.

Conclusion

As far as we know, this is the first study that combines WGCNA and machine learning algorithms to screen for potential biomarkers of IDCM-HF. Our findings suggest that AQP3 and CYP2J2 could be used as novel diagnostic markers and treatment targets of IDCM-HF.

Contemporary Challenges of Regenerative Therapy in Patients with Ischemic and Non-Ischemic Heart Failure

It has now been almost 20 years since first clinical trials of stem cell therapy for heart repair were initiated. While initial preclinical data were promising and suggested that stem cells may be able to directly restore a diseased myocardium, this was never unequivocally confirmed in the clinical setting. Clinical trials of cell therapy did show the process to be feasible and safe. However, the clinical benefits of this treatment modality in patients with ischemic and non-ischemic heart failure have not been consistently confirmed. What is more, in the rapidly developing field of stem cell therapy in patients with heart failure, relevant questions regarding clinical trials' protocol streamlining, optimal patient selection, stem cell type and dose, and the mode of cell delivery remain largely unanswered. Recently, novel approaches to myocardial regeneration, including the use of pluripotent and allogeneic stem cells and cell-free therapeutic approaches, have been proposed. Thus, in this review, we aim to outline current knowledge and highlight contemporary challenges and dilemmas in clinical aspects of stem cell and regenerative therapy in patients with chronic ischemic and non-ischemic heart failure.

Elevated α-hydroxybutyrate dehydrogenase is associated with in-hospital mortality in non-ischemic dilated cardiomyopathy

Background

Previous Study Found That Implantation of a Cardioverter-Defibrillator Likely Caused a Worse Prognosis in Older Patients With non-Ischemic Systolic Heart Failure. This Suggests That More Precise Risk Stratification Is Needed in Elderly Patients. We Conducted a Retrospective Study to Evaluate the Association of α-Hydroxybutyrate Dehydrogenase (α-HBDH) With Mortality During Hospitalization in Elderly Patients With non-Ischemic Dilated Cardiomyopathy (NIDCM).

Methods

1,019 Elderly Patients (age ≥60 Years) Diagnosed With NIDCM Were Retrospectively Enrolled From January 2010 to December 2019. Univariate and Multivariate Analyses Were Showed to Explore the Relationship Between α-HBDH and in- Hospital Death.

Results

Patients in elevated α-HBDH group (>182 U/L) had a longer hospital stays and higher in-hospital mortality. Univariate logistics regression analysis showed that elevated α-HBDH was significantly related to mortality (OR: 7.004, 95% CI: 3.583–13.693, p < 0.001). Receiver operator characteristic (ROC) curve analysis reflected that α-HBDH levels had excellent predictive power for in-hospital death (AUC = 0.810, 95% CI: 0.745–0.876, p < 0.001). After adjustment of age, serum creatine, albumin and LVEF, multivariate regression analysis validated the association of elevated α-HBDH with increased risk of in-hospital death (p < 0.05).

Conclusions

Elevated α-HBDH level is significantly related to in-hospital mortality in older patients with NIDCM.

Metabolite Signature in the Carriers of Pathogenic Genetic Variants for Cardiomyopathy: A Population-Based METSIM Study

Hypertrophic (HCM) and dilated (DCM) cardiomyopathies are among the leading causes of sudden cardiac death. We identified 38 pathogenic or likely pathogenic variant carriers for HCM in three sarcomere genes (MYH7, MYBPC3, TPMI) among 9.928 participants of the METSIM Study having whole exome sequencing data available. Eight of them had a clinical diagnosis of HCM. We also identified 20 pathogenic or likely pathogenic variant carriers for DCM in the TTN gene, and six of them had a clinical diagnosis of DCM. The aim of our study was to investigate the metabolite signature in the carriers of the pathogenic or likely pathogenic genetic variants for HCM and DCM, compared to age- and body-mass-index-matched controls. Our novel findings were that the carriers of pathogenic or likely pathogenic variants for HCM had significantly increased concentrations of bradykinin (des-arg 9), vanillactate, and dimethylglycine and decreased concentrations of polysaturated fatty acids (PUFAs) and lysophosphatidylcholines compared with the controls without HCM. Additionally, our novel findings were that the carriers of pathogenic or likely pathogenic variants for DCM had significantly decreased concentrations of 1,5-anhydrogluticol, histidine betaine, N-acetyltryptophan, and methylsuccinate and increased concentrations of trans-4-hydroxyproline compared to the controls without DCM. Our population-based study shows that the metabolite signature of the genetic variants for HCM and DCM includes several novel metabolic pathways not previously described.

Cell Therapy in Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is the most common cause of hospitalisation for heart failure. However, only limited effective treatments are available. Recent evidence suggests that HFpEF may result from a systemic proinflammatory state, microvascular endothelial inflammation and microvascular rarefaction. Formation of new microvasculature in ischaemic tissues is dependent on CD34+ cells, which incorporate into the newly developing vasculature and produce pro-angiogenic cytokines. In HFpEF patients, worsening of diastolic function appears to correlate with decreased numbers of CD34+ cells. Therefore, it is plausible that increasing the myocardial numbers of CD34+ cells could theoretically lead to improved microvascular function and improved diastolic parameters in HFpEF. In accordance with this hypothesis, recent pilot clinical data suggest that CD34+ cell therapy may indeed be associated with improved diastolic function and better functional capacity in HFpEF patients and could thus represent a promising novel therapeutic modality for this patient population.

Transendocardial CD34+ Cell Therapy Improves Local Mechanical Dyssynchrony in Patients With Nonischemic Dilated Cardiomyopathy

We investigated the effects of cell therapy on local mechanical dyssynchrony (LMD) in patients with nonischemic dilated cardiomyopathy (NICM). We analyzed electromechanical data of 30 NICM patients undergoing CD34⁺ cell transplantation. All patients underwent bone marrow stimulation; CD34⁺ cells were collected by apheresis and injected transendocardially. At baseline and at 6 months after therapy, we performed electromechanical mapping and measured unipolar voltage (UV) and LMD at cell injection sites. LMD was defined as a temporal difference between global and segmental peak systolic displacement normalized to the average duration of the RR interval. Favorable clinical response was defined as increase in the left ventricular ejection fraction (LVEF) ≥5% between baseline and 6 months. Using paired electromechanical point-by-point analysis, we were able to identify 233 sites of CD34⁺ cell injections in 30 patients. We found no overall differences in local UV between baseline and 6 months (10.7 ± 4.1 mV vs 10.0 ± 3.6 mV, P = 0.42). In contrast, LMD decreased significantly (17 ± 17% at baseline vs 13 ± 12% at 6 months, P = 0.00007). Favorable clinical response at 6 months was found in 19 (63%) patients (group A), and 11 (37%) patients did not respond to cell therapy (group B). At baseline, the two groups did not differ in age, gender, LVEF, or N terminal-pro brain natriuretic peptide (NT-proBNP) levels. Similarly, we found no differences in baseline UV (9.5 ± 2.9 mV in group A vs 8.6 ± 2.4 mV in group B, P = 0.41) or LMD at cell injection sites (17 ± 19% vs 16 ± 14%, P = 0.64). In contrast, at 6 months, we found higher UV in group A (10.0 ± 3.1 mV vs 7.4 ± 1.9 mV in group B, P = 0.04). Furthermore, when compared with group B, patients in group A displayed a significantly lower LMD (11 ± 12% vs 16 ± 10%, P = 0.002). Thus, it appears that favorable clinical effects of cell therapy in NICM patients may be associated with a decrease of LMD at cell injection sites.

3D models of dilated cardiomyopathy: Shaping the chemical, physical and topographical properties of biomaterials to mimic the cardiac extracellular matrix

The pathophysiology of dilated cardiomyopathy (DCM), one major cause of heart failure, is characterized by the dilation of the heart but remains poorly understood because of the lack of adequate in vitro models. Current 2D models do not allow for the 3D organotypic organization of cardiomyocytes and do not reproduce the ECM perturbations. In this review, the different strategies to mimic the chemical, physical and topographical properties of the cardiac tissue affected by DCM are presented. The advantages and drawbacks of techniques generating anisotropy required for the cardiomyocytes alignment are discussed. In addition, the different methods creating macroporosity and favoring organotypic organization are compared. Besides, the advances in the induced pluripotent stem cells technology to generate cardiac cells from healthy or DCM patients will be described. Thanks to the biomaterial design, some features of the DCM extracellular matrix such as stiffness, porosity, topography or chemical changes can impact the cardiomyocytes function in vitro and increase their maturation. By mimicking the affected heart, both at the cellular and at the tissue level, 3D models will enable a better understanding of the pathology and favor the discovery of novel therapies.

Diagnostic biomarkers of dilated cardiomyopathy

BACKGROUND

Dilated cardiomyopathy (DCM) is a condition involving dilation of cardiac chambers, which results in contraction impairment. Besides invasive and non-invasive diagnostic procedures, cardiac biomarkers are of great importance in both diagnosis and prognosis of the disease. These biomarkers are categorized into three groups based on their site; cardiomyocyte biomarkers, microenvironmental biomarkers and macroenvironmental biomarkers.

AIMS

In this review, an overview of characteristics, epidemiology, etiology and clinical manifestations of DCM is provided. In addition, the most important biomarkers, of all three categories, and their diagnostic and prognostic values are discussed.

CONCLUSION

Considering the association of DCM with conditions such as infections and autoimmunity, which are prevalent among the population, introducing efficient diagnostic tools is of high value for the early detection of DCM to prevent its severe complications. The three discussed classes of biomarkers are potential candidates for the detection of DCM. However, further studies are necessary in this regard.

Relationship Between Myocardial Perfusion and Myocardial Function in Dilated Cardiomyopathy by Shown Ultrasonography

Myocardial contrast echocardiography (MCE) and two-dimensional speckle tracking echocardiography (2D-STE) were used to detect left ventricular myocardial microcirculation perfusion and myocardial systolic function in dilated cardiomyopathy (DCM) and to explore the relationship between the two.Conventional ultrasound, MCE, and 2D-STE examinations were performed on 30 patients and 30 controls. Left ventricular microcirculation perfusion, left ventricular longitudinal strain (GLS), and circumferential strain (GCS) were analyzed to further compare the correlation between left ventricular perfusion and myocardial strain parameters.Regional myocardial perfusion was reduced in patients with DCM, manifesting as a decrease in the rising slope (A) of the mid-segment of the posterior septum, the peak intensity (PI) of the mid-segment of the anterior septum and the posterior septum, the apical segment of the lateral wall, the area under the curve (AUC) of the posterior septum, the basal segment of the posterior wall, the anterior septum, posterior septum, posterior wall, mid-segment of the lateral wall, and apical segment of the lateral wall and the overall average PI and AUC of the mid-segment, compared with that in the controls (P < 0.05). The left ventricular systolic function and the strain parameters GLS and GCS of DCM patients were lower than those of the controls (P < 0.001). Correlation analysis revealed a positive correlation between the A of the mitral valve and GCS (r = 0.372, P = 0.043), and MV-E/e' had a positive correlation with the AUC of the basal and intermediate segments (r = 0.379, P = 0.039; r = 0.404, P = 0.027).In patients with DCM, regional myocardial microcirculation perfusion is reduced, and myocardial strain is impaired. Myocardial perfusion has a good positive correlation with myocardial mechanics.

Clinical trial in a dish using iPSCs shows lovastatin improves endothelial dysfunction and cellular cross-talk in LMNA cardiomyopathy

Mutations in LMNA, the gene that encodes lamin A and C, causes LMNA-related dilated cardiomyopathy (DCM) or cardiolaminopathy. LMNA is expressed in endothelial cells (ECs); however, little is known about the EC-specific phenotype of LMNA-related DCM. Here, we studied a family affected by DCM due to a frameshift variant in LMNA Human induced pluripotent stem cell (iPSC)-derived ECs were generated from patients with LMNA-related DCM and phenotypically characterized. Patients with LMNA-related DCM exhibited clinical endothelial dysfunction, and their iPSC-ECs showed decreased functionality as seen by impaired angiogenesis and nitric oxide (NO) production. Moreover, genome-edited isogenic iPSC lines recapitulated the EC disease phenotype in which LMNA-corrected iPSC-ECs showed restoration of EC function. Simultaneous profiling of chromatin accessibility and gene expression dynamics by combining assay for transposase-accessible chromatin using sequencing (ATAC-seq) and RNA sequencing (RNA-seq) as well as loss-of-function studies identified Krüppel-like factor 2 (KLF2) as a potential transcription factor responsible for the EC dysfunction. Gain-of-function studies showed that treatment of LMNA iPSC-ECs with KLF2 agonists, including lovastatin, rescued the EC dysfunction. Patients with LMNA-related DCM treated with lovastatin showed improvements in clinical endothelial dysfunction as indicated by increased reactive hyperemia index. Furthermore, iPSC-derived cardiomyocytes (iPSC-CMs) from patients exhibiting the DCM phenotype showed improvement in CM function when cocultured with iPSC-ECs and lovastatin. These results suggest that impaired cross-talk between ECs and CMs can contribute to the pathogenesis of LMNA-related DCM, and statin may be an effective therapy for vascular dysfunction in patients with cardiolaminopathy.

Myocardial ischemia and coronary disease in heart failure

Heart failure is a complex clinical syndrome and represents the final path of numerous heart diseases. Coronary artery disease is recognized as the primary risk factor for heart failure development, being the main etiological factor in more than 50% of heart failure patients in North America and Europe. Regardless of overt coronary artery disease, myocardial ischemia is a common finding in failing hearts, likely due to structural or functional coronary circulation alterations. Ischemia is a self-propagating process which irreversibly impairs the cardiac function and negatively impacts prognosis. Thus, a better and thorough understanding of myocardial ischemia pathophysiology in heart failure would likely lead to significantly improved outcomes in these patients. This review aims to describe the mechanisms of myocardial ischemia and coronary artery disease in heart failure, focusing on coronary circulation dysfunctions due to increased parietal stress or non-obstructive coronary disease, and discussing the association and management of coronary artery disease in patients with heart failure.

Peripheral Vascular Function in Dilated Cardiomyopathy of Different Etiology

Vascular function in dilated cardiomyopathy of different etiology has been poorly investigated. Moreover, reference values of flow-mediated dilation (FMD) in chronic heart failure (CHF) need to be updated according to the new standardized protocols. We characterized the vascular impairment in different stages of post-ischemic dilated cardiomyopathy (PI-DC) or idiopathic dilated cardiomyopathy (I-DC). Eighty consecutive outpatients with CHF in different New York Heart Association (NYHA) classes (45 PI-DC, 35 I-DC) and 50 control subjects underwent FMD and brachial distensibility coefficient measurement. Patients with CHF showed a marked impairment in FMD compared with controls that worsened from classes NYHA I-II to III-IV, independently of etiology ( P < .05). New York Heart Association I-II PI-DC patients showed a worse FMD compared with NYHA I-II I-DC patients ( P < .05). Brachial distensibility coefficient values were significantly lower in patients with CHF compared with controls ( P < .001) without differences between PI-DC and I-DC. In conclusion, advanced CHF is characterized by vascular impairment that is independent of etiology. In the early stages of CHF, endothelial dysfunction is more severe in patients with PI-DC compared with I-DC probably due to the high cardiovascular risk profile. In I-DC, vascular function impairment is independent of cardiovascular risk factors and could participate in the pathogenesis of I-DC.

Stem Cell Therapy for Chronic and Advanced Heart Failure

PURPOSE OF REVIEW

The purpose of this review is to discuss recent advances in the field of cell therapy in patients with heart failure with reduced ejection fraction (HFrEF) of ischemic (iCMP) and nonischemic (dCMP) etiology, heart failure with preserved ejection fraction (HFpEF), and in advanced heart failure patients undergoing mechanical circulatory support (LVAD).

RECENT FINDINGS

In HFrEF patients (iCMP and dCMP cohorts), autologous and/or allogeneic cell therapy was shown to improve myocardial performance, patients' functional capacity, and neurohumoral activation. In HFpEF patient population, the concept of cell therapy in novel and remains largely unexplored. However, initial data are very encouraging and suggest at least a similar benefit in improvements of myocardial performance (also diastolic function of the left ventricle), exercise capacity, and neurohumoral activation. Recently, cell therapy was explored in the sickest population of advanced heart failure patients undergoing LVAD support also showing a potential benefit in promoting myocardial reverse remodeling and recovery. In the past decade, several cell therapy-based clinical trials showed promising results in various chronic and advanced heart failure patient cohorts. Future cell treatment strategies should aim for more personalized therapeutic approaches by defining optimal stem cell type or their combination, dose, and delivery method for an individual patient adjusted for patient's age and stage/duration of heart failure.

BNP as a New Biomarker of Cardiac Thyroid Hormone Function

Background

Cardiac re-expression of fetal genes in patients with heart failure (HF) suggests the presence of low cardiac tissue thyroid hormone (TH) function. However, serum concentrations of T3 and T4 are often normal or subclinically low, necessitating an alternative serum biomarker for low cardiac TH function to guide treatment of these patients. The clinical literature suggests that serum Brain Natriuretic Peptide (BNP) levels are inversely associated with serum triiodo-L-thyronine (T3) levels. The objective of this study was to investigate BNP as a potential serum biomarker for TH function in the heart.

Methods

Two animal models of thyroid hormone deficiency: (1) 8-weeks of propyl thiouracil-induced hypothyroidism (Hypo) in adult female rats were subsequently treated with oral T3 (10 μg/kg/d) for 3, 6, or 14 days; (2) HF induced by coronary artery ligation (myocardial infarction, MI) in adult female rats was treated daily with low dose oral T3 (5 μg/kg/d) for 8 or 16 wks.

Results

Six days of T3 treatment of Hypo rats normalized most cardiac functional parameters. Serum levels of BNP increased 5-fold in Hypo rats, while T3 treatment normalized BNP by day 14, showing a significant inverse relationship between serum BNP and free or total T3 concentrations. Myocardial BNP mRNA was increased 2.5-fold in Hypo rats and its expression was decreased to normal values by 14 days of T3 treatment. Measurements of hemodynamic function showed significant dysfunction in MI rats after 16 weeks, with serum BNP increased by 4.5-fold and serum free and total T3 decreased significantly. Treatment with T3 decreased serum BNP while increasing total T3 indicating an inverse correlation between these two biologic factors (r ² = 0.676, p < 0.001). Myocardial BNP mRNA was increased 5-fold in MI rats which was significantly decreased by T3 over 8 to 16 week treatment periods.

Conclusions

Results from the two models of TH dysfunction confirmed an inverse relationship between tissue and serum T3 and BNP, such that the reduction in serum BNP could potentially be utilized to monitor efficacy and dosing of T3 treatment. Thus, serum BNP may serve as a reliable biomarker for cardiac TH function.

Additive prognostic value of red cell distribution width over late gadolinium enhancement on CMR in patients with non-ischemic dilated cardiomyopathy

Elevated red cell distribution width (RDW) and late gadolinium enhancement on cardiac magnetic resonance (LGE-CMR) are both poor prognostic factors. This study examined the relationship between RDW and LGE-CMR characteristics in patients with non-ischemic dilated cardiomyopathy (NICM), and investigated whether the additive prognostic value of RDW as an integrative systemic factor over LGE-CMR exists or not. A total of consecutive 378 patients who underwent CMR at two general hospitals in South Korea were retrospectively analyzed. The primary endpoint was a composite of all-cause death, hospitalizations due to worsening heart failure and major arrhythmic events. During a mean follow-up period of 40.8 months, 151 (39.9%) patients experienced primary endpoints. The RDW value was significantly higher in patients with LGE than in those without LGE (13.7 ± 1.5% vs. 13.3 ± 1.4%, p = 0.034), but it was not associated with the extent or distribution patterns of the LGE. Addition of RDW into the model with clinical risk factors and LGE-CMR characteristics led to a significant improvement in the prediction of worse outcomes (χ² increased from 73 to 82; p = 0.023). RDW could provide incremental predictive value for adverse clinical events beyond LGE-CMR data in NICM patients.

Genetic Basis and Genotype-Phenotype Correlations in Han Chinese Patients with Idiopathic Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is one of the leading causes of heart failure. A large proportion of genetic cause remains unexplained, especially in idiopathic DCM. We performed target next-generation sequencing of 102 genes which were known causes or candidate genes for cardiomyopathies and channelpathies in 118 prospectively recruited Han Chinese patients with idiopathic DCM. 41 of the 118 patients carried 40 pathogenic or likely pathogenic variants, providing a molecular diagnosis in 34.7% of patients. 32 of these variants were novel. TTN truncating variants were predominant, with a frequency of 31.0%, followed by variants of LMNA (14.3%), RBM20 (4.8%), and NEXN (4.8%). These 4 genes accounted for over half variants identified. No significant difference in clinical characteristics or rates of reaching the composite end point (cardiac transplantation and death from cardiac causes) between pathogenic or likely pathogenic variant carriers and noncarriers (hazard ratio 1.11, 95% CI: 0.41 to 3.00), or between patients with TTN truncating variants or without (hazard ratio 0.49, 95% CI: 0.36 to 6.10). In our prospective study, we first determined the overall genetic profiles and genotype-phenotype correlations in Han Chinese idiopathic DCM patients, which could provide insight for genetic diagnosis of DCM in this population.

Indexes of Angiogenic Activation in Myocardial Samples of Patients with Advanced Chronic Heart Failure

Background and objectives: Ischemic and idiopathic heart failure are characterized by reactive cardiac fibrosis and impaired vasculogenesis involving pro-angiogenic factors such as angiogenin, angiopoietin-1 (Ang-1), and angiopoietin-2 (Ang-2), as demonstrated in experimental models of heart failure. However, differences in the molecular pathways between these cardiomyopathies are still unclear. In this short communication, we evaluate and compare the expression of pro-angiogenic molecules in the heart tissue of patients with advanced chronic heart failure (CHF) of ischemic vs. nonischemic etiology. Materials and Methods: We obtained heart tissue at transplantation from left ventricular walls of 16 explanted native hearts affected by either ischemic (ICM) or nonischemic dilated cardiomyopathy (NIDCM). Tissue samples were examined using immunohistochemistry for angiogenic molecules. Results: We found immunopositivity (I-pos) for angiopoietin-1 mainly in the cardiomyocytes, while we observed I-pos for Ang-2 and Tie-2 receptor mainly in endothelial cells. Expression of Procollagen-I (PICP), angiogenin, Ang-1, and Tie-2 receptor was similar in ICM and NIDCM. In contrast, endothelial immunopositivity for Ang-2 was higher in ICM samples than NIDCM (p = 0.03). Conclusions: In our series of CHF heart samples, distribution of Ang-1 and angiogenin was higher in cardiomyocytes while that of Ang-2 was higher in endothelial cells; moreover, Ang-2 expression was higher in ICS than NIDCM. Despite the small series examined, these findings suggest different patterns of angiogenic stimulation in ICM and NIDCM, or at least a more altered endothelial integrity in ICD. Our data may contribute to a better understanding of the angiogenesis signaling pathways in CHF. Further studies should investigate differences in the biochemical processes leading to heart failure.

Mesenchymal Stem Cell Secretion of SDF-1α Modulates Endothelial Function in Dilated Cardiomyopathy

Background

Endothelial dysfunction contributes to the pathophysiology of dilated cardiomyopathy (DCM). Allogeneic but not autologous mesenchymal stem cells (MSCs) improve endothelial function in DCM patients. We hypothesized that these effects are modulated by release of stromal derived factor-1α (SDF-1α).

Methods

Plasma TNFα and endothelial progenitor cell-colony forming units (EPC-CFUs) were assessed at baseline and 3-months post-injection in a subset of POSEIDON-DCM patients that received autologous (n = 11) or allogeneic (n = 10) MSCs. SDF-1α secretion by MSCs, endothelial cell (EC) TNFα mRNA expression, and levels of reactive oxygen species (ROS) in response to SDF-1α were measured in vitro.

Results

As previously shown, DCM patients (n = 21) had reduced EPC-CFUs at baseline (3 ± 3), which were restored to normal by allogeneic MSCs 3-months post-treatment (Δ10 ± 4). DCM patients had elevated baseline plasma TNFα (n = 15, 22 ± 9.4 pg/mL). Allogeneic MSCs (n = 8) decreased, and autologous MSCs (n = 7) increased, plasma TNFα (−7.1 ± 3.1 vs. 22.2 ± 17.1 pg/mL, respectively; P = 0.0005). In culture, autologous MSCs (n = 11) secreted higher levels of SDF-1α than allogeneic MSCs (n = 6) [76.0 (63.7, 100.9) vs. 22.8 (7.2, 43.5) pg/mL, P = 0.0002]. SDF-1α and plasma TNFα negatively correlated with EPC-CFUs in both treatment groups (R = −0.7, P = 0.0004). ECs treated with 20 ng SDF-1α expressed lower levels of TNFα mRNA than cells treated with 100 ng (0.7 ± 0.2 vs. 2.1 ± 0.3, P = 0.0008). SDF-1α at low but not high concentration inhibited the generation of ROS.

Conclusion

MSC secretion of SDF-1α inversely correlates with EPC-CFU production in DCM patients and therefore may be a modulator of MSC therapeutic effect in this clinical setting.

Clinical Trial Registration

https://clinicaltrials.gov/ct2/show/NCT01392625, identifier NCT01392625.

Microvascular Dysfunction in Dilated Cardiomyopathy: A Quantitative Stress Perfusion Cardiovascular Magnetic Resonance Study

OBJECTIVES

This study sought to quantify myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) in dilated cardiomyopathy (DCM) and examine the relationship between myocardial perfusion and adverse left ventricular (LV) remodeling.

BACKGROUND

Although regarded as a nonischemic condition, DCM has been associated with microvascular dysfunction, which is postulated to play a role in its pathogenesis. However, the relationship of the resulting perfusion abnormalities to myocardial fibrosis and the degree of LV remodeling is unclear.

METHODS

A total of 65 patients and 35 healthy control subjects underwent adenosine (140 μg/kg/min) stress perfusion cardiovascular magnetic resonance with late gadolinium enhancement imaging. Stress and rest MBF and MPR were derived using a modified Fermi-constrained deconvolution algorithm.

RESULTS

Patients had significantly higher global rest MBF compared with control subjects (1.73 ± 0.42 ml/g/min vs. 1.14 ± 0.42 ml/g/min; p < 0.001). In contrast, global stress MBF was significantly lower versus control subjects (3.07 ± 1.02 ml/g/min vs. 3.53 ± 0.79 ml/g/min; p = 0.02), resulting in impaired MPR in the DCM group (1.83 ± 0.58 vs. 3.50 ± 1.45; p < 0.001). Global stress MBF (2.70 ± 0.89 ml/g/min vs. 3.44 ± 1.03 ml/g/min; p = 0.017) and global MPR (1.67 ± 0.61 vs. 1.99 ± 0.50; p = 0.047) were significantly reduced in patients with DCM with LV ejection fraction ≤35% compared with those with LV ejection fraction >35%. Segments with fibrosis had lower rest MBF (mean difference: -0.12 ml/g/min; 95% confidence interval: -0.23 to -0.01 ml/g/min; p = 0.035) and lower stress MBF (mean difference: -0.15 ml/g/min; 95% confidence interval: -0.28 to -0.03 ml/g/min; p = 0.013).

CONCLUSIONS

Patients with DCM exhibit microvascular dysfunction, the severity of which is associated with the degree of LV impairment. However, rest MBF is elevated rather than reduced in DCM. If microvascular dysfunction contributes to the pathogenesis of DCM, then the underlying mechanism is more likely to involve stress-induced repetitive stunning rather than chronic myocardial hypoperfusion.

Stem Cell and Left Ventricular Assist Device Combination Therapy

Ventricular assist device (VAD) technology has evolved significantly over the past decades and currently represents one of the most important treatment strategies for patients with advanced chronic heart failure. There is increasing evidence that in selected patients undergoing long-term VAD support, improvement of myocardial structure and function may occur. However, there seems to be a significant discrepancy between structural and functional recovery of the failing myocardium, as only a small fraction of VAD-supported patients demonstrate reverse structural remodeling and eventually reach clinically significant and stable, functional improvement. More recently, cell therapy has gained a growing interest in the heart failure community because of its potential to augment reverse remodeling of the failing myocardium. Although theoretically the combination of long-term VAD support and cell therapy may offer significant advantages over using these therapeutic modalities separately, it remains largely unexplored. This review aims to summarize the current state of the art of the effects of VAD support and cell therapy on the reverse remodeling of the failing myocardium and to discuss the rationale for using a combined treatment strategy to further promote myocardial recovery in patients with advanced chronic heart failure.

Proteomic signature of circulating extracellular vesicles in dilated cardiomyopathy

Dilated cardiomyopathy (DCM) remains a major cause of heart failure and carries a poor prognosis despite important advances in recent years. Better disease characterization using novel molecular techniques is needed to refine its progression. This study explored the proteomic signature of plasma-derived extracellular vesicles (EVs) obtained from DCM patients and healthy controls using size-exclusion chromatography (SEC). EV-enriched fractions were analyzed by liquid chromatography-mass spectrometry (LC-MS/MS). Raw data obtained from LC-MS/MS were analyzed against the Uniprot human database using MaxQuant software. Additional analyses using Perseus software were based on the Intensity-Based Absolute Quantification (iBAQ) values from MaxQuant analyses. A total of 90.07 ± 21 proteins (227 different proteins) in the DCM group and 96.52 ± 17.91 proteins (183 different proteins) in the control group were identified. A total of 176 proteins (74.6%) were shared by controls and DCM patients, whereas 51 proteins were exclusive for the DCM group and 7 proteins were exclusive for the control group. Fibrinogen (α, β and γ chain), serotransferrin, α-1-antitrypsin, and a variety of apolipoprotein family members (C-I, C-III, D, H or β-2-glycoprotein, and J or clusterin) were clustered in SEC-EVs derived from DCM patients relative to controls (p < 0.05). Regarding Gene Ontology analysis, response to stress and protein activation-related proteins were enriched in DCM-EVs compared with controls. Thus, the present study reports the distinct proteomic signature of circulating DCM-EVs compared with control-EVs. Furthermore, we confirm that SEC obtains highly purified EV fractions from peripheral blood samples for subsequent use in determining disease-specific proteomic signatures.

Identification of new biophysical markers for pathological ventricular remodelling in tachycardia-induced dilated cardiomyopathy

Our aim was to identify biophysical biomarkers of ventricular remodelling in tachycardia-induced dilated cardiomyopathy (DCM). Our study includes healthy controls (N = 7) and DCM pigs (N = 10). Molecular analysis showed global myocardial metabolic abnormalities, some of them related to myocardial hibernation in failing hearts, supporting the translationality of our model to study cardiac remodelling in dilated cardiomyopathy. Histological analysis showed unorganized and agglomerated collagen accumulation in the dilated ventricles and a higher percentage of fibrosis in the right (RV) than in the left (LV) ventricle (P = .016). The Fourier Transform Infrared Spectroscopy (FTIR) 1st and 2nd indicators, which are markers of the myofiber/collagen ratio, were reduced in dilated hearts, with the 1st indicator reduced by 45% and 53% in the RV and LV, respectively, and the 2nd indicator reduced by 25% in the RV. The 3rd FTIR indicator, a marker of the carbohydrate/lipid ratio, was up-regulated in the right and left dilated ventricles but to a greater extent in the RV (2.60-fold vs 1.61-fold, P = .049). Differential scanning calorimetry (DSC) showed a depression of the freezable water melting point in DCM ventricles - indicating structural changes in the tissue architecture - and lower protein stability. Our results suggest that the 1st, 2nd and 3rd FTIR indicators are useful markers of cardiac remodelling. Moreover, the 2nd and 3rd FITR indicators, which are altered to a greater extent in the right ventricle, are associated with greater fibrosis.

Variable endothelial cell function restoration after initiation of two antiretroviral regimens in HIV-infected individuals

Background

The effect of ART on endothelial cell function is incompletely characterized.

Methods

We performed a 24 week prospective, case-control and comparative pilot study of ART-naive HIV-infected patients who started a darunavir- or rilpivirine-based regimen, matched with non-HIV-infected volunteers, to compare changes at week 24 from baseline in levels of circulating endothelial cells (CECs), endothelial progenitor cells (EPCs) and circulating angiogenic cells, as well as changes in immune-activation markers.

Results

The study population comprised 24 HIV-infected patients and 24 non-infected volunteers. Both HIV groups completely suppressed viraemia. HIV-infected patients had higher levels of activation markers than the control group in CD8 T cells at baseline; these decreased after 24 weeks of treatment, but without reaching the levels of the control group. No statistical differences in immune activation were seen between the darunavir and rilpivirine groups. Levels of CECs were higher and levels of EPCs and circulating angiogenic cells were lower in HIV-infected patients than in the control group, although these parameters were similar between the darunavir group and the control group, but not the rilpivirine group, at week 24. An unfavourable association was observed between rilpivirine, age and increased number of CECs.

Conclusions

Restoration of circulating levels of EPCs and CECs in darunavir-treated patients was greater than in those treated with rilpivirine, suggesting ongoing endothelial repair mechanisms.

Stem Cell Therapy in Patients with Chronic Nonischemic Heart Failure

Aim of the Review

The aim of this review is to discuss recent advances in clinical aspects of stem cell therapy in chronic nonischemic heart failure (DCMP) with emphasis on patient selection, stem cell types, and delivery methods.

Recent Findings

Several stem cell types have been considered for the treatment of DCMP patients. Bone marrow-derived cells and CD34⁺ cells have been demonstrated to improve myocardial performance, functional capacity, and neurohumoral activation. Furthermore, allogeneic mesenchymal stem cells were also shown to be effective in improving heart function in this patient population; this may represent an important step towards the development of a standardized stem cell product for widespread clinical use in patients with DCMP.

Summary

The trials of stem cell therapy in DCMP patients have shown some promising results, thus making DCMP apparently more inviting target for stem cell therapy than chronic ischemic heart failure, where studies to date failed to demonstrate a consistent effect of stem cells on myocardial performance. Future stem cell strategies should aim for more personalized therapeutic approach by establishing the optimal stem cell type or their combination, dose, and delivery method for an individual patient adjusted for patient's age and stage of the disease.

Downregulation of circulating MOTS-c levels in patients with coronary endothelial dysfunction

BACKGROUND

MOTS-c is one of the newly identified mitochondrial-derived peptides which play a role in regulating metabolic homeostasis. The current study aimed to investigate whether circulating MOTS-c levels are also associated with endothelial dysfunction(ED) in patients without significant structural coronary lesions.

METHODS

Forty patients undergoing coronary angiography and endothelial function testing for clinical indications of recurrent angina with no structural coronary lesions were included in the study. They were divided into two groups based on coronary blood flow response to intracoronary acetylcholine (ACh) as normal endothelial function (≥ 50% increase from baseline) or ED, (n=20 each). Aortic plasma samples were collected at the time of catheterization for analysis of circulating MOTS-c levels by ELISA. The effect of MOTS-c on vascular reactivity was assessed in organ chambers using aortic rings collected from rats and renal artery stenosis (RAS) mice.

RESULTS

Baseline characteristics were similar between the two groups. MOTS-c plasma levels were lower in patients with ED compared with patients with normal endothelial function (p=0.007). Furthermore, plasma MOTS-c levels were positively correlated with microvascular (p=0.01) and epicardial (p=0.02) coronary endothelial function. Although MOTS-c did not have direct vasoactive effects, pretreating aortic rings from rats or RAS mice with MOTS-c (2μg/ml) improved vessel responsiveness to ACh compared with vessels without MOTS-c treatment.

CONCLUSION

Lower circulating endogenous MOTS-c levels in human subjects are associated with impaired coronary endothelial function. In rodents, MOTS-c improves endothelial function in vitro. Thus, MOTS-c represents a novel potential therapeutic target in patients with ED.

The atrial appendage as a suitable source to generate cardiac-derived adherent proliferating cells for regenerative cell-based therapies

Cardiac-derived adherent proliferating (CardAP) cells obtained from endomyocardial biopsies (EMBs) with known anti-fibrotic and pro-angiogenic properties are good candidates for the autologous therapy of end-stage cardiac diseases such as dilated cardiomyopathy. However, due to the limited number of CardAP cells that can be obtained from EMBs, our aim is to isolate cells with similar properties from other regions of the heart with comparable tissue architecture. Here, we introduce the atrial appendage as a candidate region. Atrial appendage-derived cells were sorted with CD90 microbeads to obtain a CD90^low cell population, which were subsequently analysed for their surface marker and gene expression profiles via flow cytometry and micro array analysis. Enzyme-linked immunosorbent assays for vascular endothelial growth factor and interleukin-8 as well as tube formation assays were performed to investigate pro-angiogenic properties. Furthermore, growth kinetic assays were performed to estimate the cell numbers needed for cell-based products. Microarray analysis revealed the expression of numerous pro-angiogenic genes and strong similarities to CardAP cells with which they also share expression levels of defined surface antigens, that is, CD29⁺ , CD44⁺ , CD45^- , CD73⁺ , CD90^low , CD105⁺ , and CD166⁺ . High secretion levels of vascular endothelial growth factor and interleukin-8 as well as improved properties of vascular structures in vitro could be detected. Based on growth parameters, cell dosages for the treatment of more than 250 patients are possible using one appendage. These results lead to the conclusion that isolating cells with regenerative characteristics from atrial appendages is feasible and permits further investigations towards allogenic cell-based therapies.

Extracellular vesicles do not contribute to higher circulating levels of soluble LRP1 in idiopathic dilated cardiomyopathy

Idiopathic dilated cardiomyopathy (IDCM) is a frequent cause of heart transplantation. Potentially valuable blood markers are being sought, and low‐density lipoprotein receptor‐related protein 1 (LRP1) has been linked to the underlying molecular basis of the disease. This study compared circulating levels of soluble LRP1 (sLRP1) in IDCM patients and healthy controls and elucidated whether sLRP1 is exported out of the myocardium through extracellular vesicles (EVs) to gain a better understanding of the pathogenesis of the disease. LRP1 α chain expression was analysed in samples collected from the left ventricles of explanted hearts using immunohistochemistry. sLRP1 concentrations were determined in platelet‐free plasma by enzyme‐linked immunosorbent assay. Plasma‐derived EVs were extracted by size‐exclusion chromatography (SEC) and characterized by nanoparticle tracking analysis and cryo‐transmission electron microscopy. The distributions of vesicular (CD9, CD81) and myocardial (caveolin‐3) proteins and LRP1 α chain were assessed in SEC fractions by flow cytometry. LRP1 α chain was preferably localized to blood vessels in IDCM compared to control myocardium. Circulating sLRP1 was increased in IDCM patients. CD9‐ and CD81‐positive fractions enriched with membrane vesicles with the expected size and morphology were isolated from both groups. The LRP1 α chain was not present in these SEC fractions, which were also positive for caveolin‐3. The increase in circulating sLRP1 in IDCM patients may be clinically valuable. Although EVs do not contribute to higher sLRP1 levels in IDCM, a comprehensive analysis of EV content would provide further insights into the search for novel blood markers.

Effects of Transendocardial CD34+ Cell Transplantation on Diastolic Parameters in Patients with Nonischemic Dilated Cardiomyopathy

We sought to evaluate the physiological background and the effects of CD34⁺ cell transplantation on diastolic parameters in nonischemic dilated cardiomyopathy patients (DCM). We enrolled 38 DCM patients with NYHA class III and LVEF < 40% who underwent transendocardial CD34⁺ cell transplantation. Peripheral blood CD34⁺ cells were mobilized by G‐CSF, collected via apheresis, and injected transendocardially in the areas of myocardial hibernation. Patients were followed for 1 year. At baseline, estimated filling pressures were significantly elevated (E/e′ ≥ 15) in 18 patients (Group A), and moderately elevated (E/e ′< 15) in 20 patients (Group B). The groups did not differ in age (54 ± 9 years vs. 52 ± 10 years; p = .62), gender (male: 85% vs. 78%; p = .57), or LVEF (31 ± 7% vs. 34 ± 6%; p = .37). When compared to Group B patients in Group A had more segments with myocardial scar (4.9 ± 2.7 vs. 2.7 ± 2.9; p = .03), myocardial hibernation (2.2 ± 1.6 vs. 0.9 ± 1.1; p = .02), and longer average local relaxation time on electroanatomical mapping (378 ± 41 ms vs. 333 ± 34 ms, p = .01). During follow‐up there was an improvement in diastolic parameters in Group A (E/e′: from 24.3 ± 12.1 to 16.3 ± 8.0; p = .005), but not in Group B (E/e′: from 10.2 ± 3.7 to 13.2 ± 9.1; p = .19). Accordingly, in Group A, we found an increase in 6‐minute walk distance (from 463 ± 83 m to 546 ± 91 m; p = .03), and a decrease in NT‐proBNP (from 2140 ± 1743 pg/ml to 863 ± 836 pg/ml; p = .02). In nonischemic DCM, diastolic dysfunction appears to correlate with areas of myocardial scar and hibernation. Transendocardial CD34⁺ cell transplantation may improve diastolic parameters in this patient cohort. Stem Cells Translational Medicine2017;6:1515–1521

Peripartum Cardiomyopathy From a Genetic Perspective

Peripartum cardiomyopathy (PPCM) is a rare, but life-threatening condition that occurs during the peripartum period in previously healthy women. Although its etiology remains unknown, potential risk factors include hypertensive disorders during pregnancy, such as preeclampsia, advanced maternal age, multiparity, multiple gestation, and African descent. Several cohort studies of PPCM revealed that the prevalence of these risk factors was quite similar. Clinically, approximately 40% of PPCM patients are complicated with hypertensive disorders during pregnancy. Because PPCM is a diagnosis of exclusion, heterogeneity is a common element in its pathogenesis. Recent genetic research has given us new aspects of the disease. PPCM and dilated cardiomyopathy (DCM) share genetic predisposition: 15% of PPCM patients were found to have genetic mutations that have been associated with DCM, and they showed a lower recovery rate. Other basic research using PPCM model mice suggests that predisposition genes related to both hypertensive and cardiac disorders via angiogenic imbalance may explain common elements of hypertensive disorders and PPCM. Furthermore, hypertensive disorders during pregnancy are now found to be a risk factor of not only PPCM, but also cardiomyopathy in the future. Understanding genetic variations allows us to stratify PPCM patients and to guide therapy. (Circ J 2016; 80: 1684-1688).

Endothelial dysfunction and coronary artery disease: assessment, prognosis, and treatment

Progress in the modification of conventional coronary risk factors and lifestyle behavior has reduced the incidence of atherosclerotic coronary artery disease; nonetheless, it continues to be the leading cause of mortality in the world. This might be attributed to the defective risk stratifying and prevention strategy for coronary artery disease. In the current clinical setting, atherosclerotic coronary artery disease risk is estimated on the basis of identifying and quantifying only traditional risk factors; it does not take into consideration nontraditional risk factors. In addition, most of the prevailing therapies for atherosclerosis are targeted toward traditional risk factors rather than atherosclerosis itself. It is desirable to develop a method that can directly assess the activity of atherogenesis at every moment. Endothelial function is an integrated index of all atherogenic and atheroprotective factors present in an individual including nontraditional factors and heretofore unknown factors, and it is reported to have additional predictive value for future cardiovascular events to traditional risk factors. Moreover, endothelial function has a pivotal role in all phases of atherosclerosis, from initiation to atherothrombotic complication, and is reversible at every phase, indicating that endothelial function-guided therapies might be effective and feasible in cardiovascular practice. Thus, the introduction of endothelial function testing into clinical practice might enable us to innovate individualized cardiovascular medicine. In this review, we summarize the current knowledge on the contribution of endothelial dysfunction to atherogenesis and review the methods that assess endothelial function. Finally, we focus on the effects of major antiatherosclerotic disease therapies on endothelial function and argue the possibility of noninvasive assessment of endothelial function aiming at individualized cardiovascular medicine.

Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes Afford New Opportunities in Inherited Cardiovascular Disease Modeling

Fundamental studies of molecular and cellular mechanisms of cardiovascular disease pathogenesis are required to create more effective and safer methods of their therapy. The studies can be carried out only when model systems that fully recapitulate pathological phenotype seen in patients are used. Application of laboratory animals for cardiovascular disease modeling is limited because of physiological differences with humans. Since discovery of induced pluripotency generating induced pluripotent stem cells has become a breakthrough technology in human disease modeling. In this review, we discuss a progress that has been made in modeling inherited arrhythmias and cardiomyopathies, studying molecular mechanisms of the diseases, and searching for and testing drug compounds using patient-specific induced pluripotent stem cell-derived cardiomyocytes.

Circulating Endothelial Progenitor Cells: Potential Biomarkers for Idiopathic Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) remains the most frequent cause of cardiac transplant and thus results in an enormous cost burden for health care systems worldwide. Although DCM is thought to be induced mainly by genetic and/or environmental factors, the cause is unknown in the majority of cases, giving rise to the term idiopathic DCM. Marked cardiac endothelial changes are associated with disease progression and outcome, and there are ongoing efforts to identify biomarkers that have diagnostic and prognostic value. Here, we discuss the potential and the limitations of circulating endothelial progenitor cells (EPCs) as minimally invasive serological biomarkers for DCM. In this context, it is essential to further evaluate their clinical utility independently of other variable factors that can also affect EPC levels such as age, gender, lifestyles, and treatments. To that end, large multicenter studies and standardized instrument settings, reagents, and sample preparation protocols are needed to confirm this.

Human umbilical cord blood derived mesenchymal stem cells improve cardiac function in cTnT(R141W) transgenic mouse of dilated cardiomyopathy

Cell transplantation is a promising strategy in regenerative medicine. Beneficial effects of bone marrow mesenchymal stem cells (BM-MSCs) on heart disease have been widely reported. However, the MSCs in these studies have been mainly derived from autologous animals, and data on MSCs from human umbilical cord blood (UCB-MSCs) are still scarce. We investigated whether intramyocardial xenogeneic administration of UCB-MSCs is beneficial for preserving heart function in a cTnT(R141W) transgenic mouse of dilated cardiomyopathy (DCM). Cultured UCB-MSCs, which were identified by there morphology, differentiation and cell surface markers, were transplanted into cTnT(R141W) transgenic mice to examine apoptosis, fibrosis, vasculogenesis and the associated Akt pathway. Moreover, we measured the expression levels of VEGF and IGF-1, which are growth factors required for differentiation into cardiomyocytes, and are also involved in cardiac regeneration and improving heart function. One month after transplantation, MSCs significantly decreased chamber dilation and contractile dysfunction in the cTnT(R141W) mice. MSCs transplanted hearts showed a significant decrease in cardiac apoptosis and its regulation by the Akt pathway. Cardiac fibrosis and cytoplasmic vacuolisation were significantly attenuated in the MSCs group. Importantly, the levels of VEGF and IGF-1 were increased in the MSCs transplanted hearts. In vitro, the MSC-conditioned medium displayed anti-apoptotic activity in h9c2 cardiomyocytes subjected to hypoxia. These results further confirm the paracrine effects of MSCs. In conclusion, UCB-MSCs preserve cardiac function after intramyocardial transplantation in a DCM mouse, and this effect may be associated with reductions in cellular apoptosis, inflammation, hypertrophy and myocardial fibrosis; in addition to; up-regulation of Akt, VEGF and IGF-1; and enhanced angiogenesis.

Early Administration of Carvedilol Protected against Doxorubicin-Induced Cardiomyopathy

This study tested for the benefits of early administration of carvedilol as protection against doxorubicin (DOX)-induced cardiomyopathy. Thirty male, adult B6 mice were categorized into group 1 (untreated control), group 2 [DOX treatment (15 mg/every other day for 2 weeks, i.p.], and group 3 [carvedilol (15 mg/kg/d, from day 7 after DOX treatment for 28 days)], and euthanized by day 35 after DOX treatment. By day 35, the left ventricular ejection fraction (LVEF) was significantly lower in group 2 than in groups 1 and 3, and significantly lower in group 3 than in group 1, whereas the left ventricular (LV) end-diastolic and LV end-systolic dimensions showed an opposite pattern to the LVEF among the three groups. The protein expressions of fibrotic (Smad3, TGF-β), apoptotic (BAX, cleaved caspase 3, PARP), DNA damage (γ-H2AX), oxidative stress (oxidized protein), mitochondrial damage (cytosolic cytochrome-C), heart failure (brain natriuretic peptide), and hypertrophic (β-MHC) biomarkers of the LV myocardium showed an opposite pattern to the LVEF among the three groups. The protein expressions of antifibrotic (BMP-2, Smad1/5), α-MHC, and phosphorylated-Akt showed an identical pattern to the LVEF among the three groups. The microscopic findings of fibrotic and collagen-deposition areas and the numbers of γ-H2AX(+) and 53BP1(+) cells in the LV myocardium exhibited an opposite pattern, whereas the numbers of endothelial cell (CD31(+), vWF(+)) markers showed an identical pattern to the LVEF among the three groups. Cardiac stem cell markers (C-kit(+) and Sca-1(+) cells) were significantly and progressively increased from group 1 to group 3. Additionally, the in vitro study showed carvedilol treatment significantly inhibited DOX-induced cardiomyoblast DNA (CD90/XRCC1(+), CD90/53BP1(+), and r-H2AX(+) cells) damage. Early carvedilol therapy protected against DOX-induced DNA damage and cardiomyopathy.

Secondary prevention strategy of cardiovascular disease using endothelial function testing

Over the past decades, secondary prevention of cardiovascular (CV) disease has improved and considerably reduced mortality rates. However, there remains a high-rate of new or recurrent CV events in those with established atherosclerotic vascular diseases. Although most of the prevailing therapies target the conventional risk factors, there is notable interindividual heterogeneity in adaptation to risk factors and response to therapies, which affects efficacy. It is desirable to have a methodology for directly assessing the functional significance of atherogenesis, and for managing individual patients based on their comprehensive vascular health. Endothelial function plays a pivotal role in all stages of atherosclerosis, from initiation to atherothrombotic complication. Endothelial function reflects the integrated effect of all the atherogenic and atheroprotective factors present in an individual, and is therefore regarded as an index of active disease process and a significant risk factor for future CV events. Moreover, improvement in endothelial function is associated with decreased risk of CV events, even in the secondary prevention setting. The introduction of endothelial function assessment into clinical practice may trigger the development of a more tailored and personalized medicine and improve patient outcomes. In this review, we summarize current knowledge on the contribution of endothelial dysfunction to atherosclerotic CV disease in the secondary prevention setting. Finally, we focus on the potential of an endothelial function-guided management strategy in secondary prevention.

Platelet endothelial cell adhesion molecule-1 mediates endothelial-cardiomyocyte communication and regulates cardiac function

Background

Dilated cardiomyopathy is characterized by impaired contractility of cardiomyocytes, ventricular chamber dilatation, and systolic dysfunction. Although mutations in genes expressed in the cardiomyocyte are the best described causes of reduced contractility, the importance of endothelial‐cardiomyocyte communication for proper cardiac function is increasingly appreciated. In the present study, we investigate the role of the endothelial adhesion molecule platelet endothelial cell adhesion molecule (PECAM‐1) in the regulation of cardiac function.

Methods and Results

Using cell culture and animal models, we show that PECAM‐1 expressed in endothelial cells (ECs) regulates cardiomyocyte contractility and cardiac function via the neuregulin‐ErbB signaling pathway. Conscious echocardiography revealed left ventricular (LV) chamber dilation and systolic dysfunction in PECAM‐1^−/− mice in the absence of histological abnormalities or defects in cardiac capillary density. Despite deficits in global cardiac function, cardiomyocytes isolated from PECAM‐1^−/− hearts displayed normal baseline and isoproterenol‐stimulated contractility. Mechanistically, absence of PECAM‐1 resulted in elevated NO/ROS signaling and NRG‐1 release from ECs, which resulted in augmented phosphorylation of its receptor ErbB2. Treatment of cardiomyocytes with conditioned media from PECAM‐1^−/− ECs resulted in enhanced ErbB2 activation, which was normalized by pre‐treatment with an NRG‐1 blocking antibody. To determine whether normalization of increased NRG‐1 levels could correct cardiac function, PECAM‐1^−/− mice were treated with the NRG‐1 blocking antibody. Echocardiography showed that treatment significantly improved cardiac function of PECAM‐1^−/− mice, as revealed by increased ejection fraction and fractional shortening.

Conclusions

We identify a novel role for PECAM‐1 in regulating cardiac function via a paracrine NRG1‐ErbB pathway. These data highlight the importance of tightly regulated cellular communication for proper cardiac function.

Intracoronary transplantation of CD34(+) cells is associated with improved myocardial perfusion in patients with nonischemic dilated cardiomyopathy

BACKGROUND

We investigated the effects of intracoronary transplantation of CD34(+) cells on myocardial perfusion in patients with nonischemic dilated cardiomyopathy (DCM).

METHODS AND RESULTS

We enrolled 21 patients with DCM (left ventricular ejection fraction [LVEF] <40%, New York Heart Association functional class III) who underwent peripheral stem cell mobilization with granulocyte-colony stimulating factor (G-CSF). CD34(+) cells were collected by means of apheresis. Patients underwent myocardial perfusion imaging, and CD34(+) cells were injected in the coronary artery supplying viable segments with reduced myocardial perfusion and regional dysfunction. Myocardial perfusion imaging was repeated 6 months later. Clinical response to stem cell therapy was predefined as a change in LVEF >5%. The majority of patients were men (81%) with an overall mean age 53 ± 9 years, LVEF 25 ± 5%, and 6-minute walking distance 354 ± 71 m. Myocardial perfusion defects at rest were observed in 86% of patients and were more common in the left anterior descending territory (50%). At 6 months' follow-up, there was a significant improvement in rest myocardial perfusion scores (6.3 ± 5.8 vs 3.1 ± 4.3; P < .001), LVEF (25 ± 7% vs 29 ± 8%; P = .005), and 6-minute walking distance (354 ± 71 m vs 404 ± 91 m; P < .001). Responders to stem cell therapy had lower summed rest perfusion score at both baseline (3.2 ± 3.0 vs 9.1 ± 6.3; P = .015) and follow-up (1.0 ± 1.5 vs 5.0 ± 5.1; P = .028).

CONCLUSIONS

CD34(+) cell transplantation may lead to improved myocardial perfusion in patients with nonischemic DCM. Patients with less severe myocardial perfusion defects at baseline may have an increased likelihood to respond to intracoronary CD34(+) cell transplantation.

Restoration of thyroid hormone balance: a game changer in the treatment of heart failure?

The link between low thyroid hormone (TH) function and heart failure is reviewed in the present report. The idea that TH dysfunction may contribute to diseases leading to HF has been discussed for over 60 yr. A growing body of evidence from animal and human studies, particularly in recent years, suggests that TH treatment may improve clinical outcomes. Indeed, if a similar amount of positive information were available for a newly developed heart drug, there is little doubt that large-scale clinical trials would be underway with considerable excitement. THs offer the promise of improving ventricular contraction and relaxation, improving coronary blood flow, and inhibiting atherosclerosis, and new results suggest they may even reduce the incidence of arrhythmias in heart diseases. Are the potential clinical benefits worth the risk of possible overdosing? After so many years, why has this question not been answered? Clearly, the concept has not been disproven. This review explores the body of clinical evidence related to TH dysfunction and heart failure, discuss insights into pathophysiological, cellular, and molecular mechanisms provided by animal research, and discuss what is needed to resolve this long-standing issue in cardiology and move forward.

Umbilical cord blood-derived mesenchymal stem cells: new therapeutic weapons for idiopathic dilated cardiomyopathy?

Dilated cardiomyopathy is the most frequent etiology of non-ischemic heart failure. In a majority of cases the causal mechanism is unknown, giving rise to the term 'idiopathic' dilated cardiomyopathy (IDCM). Major pathological derangements include patchy interstitial fibrosis, degenerated cardiomyocytes, and dilatation of the cardiac chambers, but recent evidence suggests that disease progression may also have the signature of cardiac endothelial dysfunction. As we better understand the molecular basis of IDCM, novel therapeutic approaches, mainly gene transfer and cell-based therapies, are being explored. Cells with regenerative potential have been extensively tested in cardiac diseases of ischemic origin in both pre-clinical and clinical settings. However, whether cell therapy has any clinical value in IDCM patients is still being evaluated. This article is a concise summary of cell therapy studies for IDCM, with a focus on recent advances that highlight the vascular potential exhibited by umbilical cord blood-derived mesenchymal stem cells (UCBMSCs). We also provide an overview of cardiac vasculature as a key regulator of subjacent myocardial integrity and function, and discuss the potential mechanisms of UCBMSC amelioration of IDCM myocardium. Consideration of these issues shows that these cells are conceivably new therapeutic agents for this complex and elusive human disorder.

Inverse relationship between raft LRP1 localization and non-raft ERK1,2/MMP9 activation in idiopathic dilated cardiomyopathy: potential impact in ventricular remodeling

BACKGROUND

Idiopathic dilated cardiomyopathy (IDCM) is characterized by adverse ventricular remodeling attributed to altered activity of extracellular matrix metalloproteinase (MMP). MMP overactivation is linked to changes in extracellular signal-regulated kinases (ERK), reportedly modulated by the low-density lipoprotein receptor-related protein 1 (LRP1) receptor. The aim of this work was to compare the levels, membrane distribution and interactions of LRP1, ERK1,2 and MMP2/9 in control and IDCM myocardium.

METHODS

Left ventricle samples from IDCM patients and control subjects were collected to analyze gene and protein expression by Real-time PCR and Western blot, respectively. Fractions enriched in cholesterol, Flotillin-1 and Caveolin-3 (rafts) were isolated from the remaining membrane (non-rafts) by sucrose gradient ultracentrifugation. We assessed the formation of LRP1-ERK1,2 complexes and MMP activity by immunoprecipitation and zymography, respectively.

RESULTS

In control myocardium, LRP1 was exclusively found in non-rafts while activation of ERK1,2 was preferentially detected in rafts. LRP1/p-ERK1,2 complexes were almost undetectable in rafts and non-rafts. In contrast, in IDCM myocardium, LRP1 moved to rafts and ERK1,2 activation was found in raft and non-raft fractions. Moreover, LRP1/p-ERK1,2 complexes were also found in both membrane fractions, although the amount was higher in non-rafts where MMP9 overactivation was exclusively detected.

CONCLUSIONS

The presented findings demonstrate a differential membrane compartmentalisation of ERK signaling in IDCM myocardium. The movement of LRP1 to rafts and the concomitant increase in non-raft-related ERK1,2/MMP9 activation may have crucial clinical implications in the progression of disease.