Familial dilated cardiomyopathy: A multidisciplinary entity, from basic screening to novel circulating biomarkers

Teen pregnancy in the setting of familial dilated cardiomyopathy: a case report

Background

Women with pre-existing forms of familial cardiomyopathy are at increased risk for morbidity and mortality due to hemodynamic changes of pregnancy. There is a lack of consensus about the management and care for these patients given the rarity of this condition. This case represents possibly the youngest pregnant familial dilated cardiomyopathy patient to deliver and the youngest patient to be fitted for a wearable cardiac defibrillator in the postpartum period.

Case Presentation

A 14-year-old gravida 1 with familial dilated cardiomyopathy presented late for prenatal care at 38 weeks, which precluded typical care plans including baseline and serial echocardiograms, medication management, and routine prenatal care. An echocardiogram showed severely decreased left ventricular systolic function compared to studies from one year prior. Three days later the patient presented in labor and had a spontaneous vaginal delivery complicated by postpartum hemorrhage. Her postpartum course was notable for persistence of decreased cardiac function testing and placement of a wearable cardiac defibrillator for prevention against life threatening arrhythmias.

Conclusion

This case report adds to the literature on pregnancy complicated by familial dilated cardiomyopathy and describes management best practices and considerations during the antepartum, intrapartum, and postpartum periods.

Prospective analysis of myocardial strain through the evolution of Chagas disease in the hamster animal model

Speckle tracking echocardiography (STE) enables early diagnosis of myocardial damage by evaluating myocardial strain. We aimed to study sequential changes in structural and ventricular functional parameters during Chagas disease (CD) natural history in an animal model. 37 Syrian hamsters were inoculated intraperitoneally with Trypanosoma cruzi (Chagas) and 20 with saline (Control). Echocardiography was performed before the infection (baseline), at 1 month (acute phase), 4, 6, and 8 months (chronic phase) using Vevo 2100 (Fujifilm Inc.) ultrasound system. Left ventricular end-diastolic diameter, Left ventricular end-systolic diameter (LVESD), Left ventricular ejection fraction (LVEF), Global longitudinal (GLS), circumferential (GCS) and radial (GRS) strain were evaluated. Tricuspid annular plane systolic excursion (TAPSE) was used to assess right ventricular function. At 8 months, animals were euthanized and LV myocardial samples were analyzed for quantitation of inflammation and fibrosis. LVEF decreased over time in Chagas group and a difference from Control was detected at 6 months (p-value of groups#time interaction = 0.005). There was a pronounced decrease in GLS, GCS and TAPSE in Chagas group (p-value of groups#time interaction = 0.003 for GLS, < 0.001 for GCS and < 0.009 for TAPSE vs Control) since the first month. LVESD, LVEF and GLS were significantly correlated to the number of inflammatory cells (r = 0.41, p = 0.046; r = − 0.42, p = 0.042; r = 0.41, p = 0.047) but not to fibrosis. In the Syrian hamster model of CD STE parameters (GLS and GCS) showed an early decrease. Changes in LVEF, LVESD, and GLS were correlated to myocardial inflammation but not to fibrosis.

A new discovered gene mutation in a child with dilated cardiomyopathy

Dilated cardiomyopathy is characterised by dilatation and impaired contraction of the left ventricle or both ventricles, which is the most common childhood cardiomyopathy. In recent years, it has been recognised that many sorts of genetic mutations may contribute to dilated cardiomyopathy. We now report a rare association of dilated cardiomyopathy with site mutation of BMPR2 gene. We did not find such an association reported in the medical literature.

Clinical Phenotypes and Prognosis of Dilated Cardiomyopathy Caused by Truncating Variants in the TTN Gene

BACKGROUND

Truncating variants in the TTN gene (TTNtv) are the commonest cause of heritable dilated cardiomyopathy. This study aimed to study the phenotypes and outcomes of TTNtv carriers.

METHODS

Five hundred thirty-seven individuals (61% men; 317 probands) with TTNtv were recruited in 14 centers (372 [69%] with baseline left ventricular systolic dysfunction [LVSD]). Baseline and longitudinal clinical data were obtained. The primary end point was a composite of malignant ventricular arrhythmia and end-stage heart failure. The secondary end point was left ventricular reverse remodeling (left ventricular ejection fraction increase by ≥10% or normalization to ≥50%).

RESULTS

Median follow-up was 49 (18-105) months. Men developed LVSD more frequently and earlier than women (45±14 versus 49±16 years, respectively; P=0.04). By final evaluation, 31%, 45%, and 56% had atrial fibrillation, frequent ventricular ectopy, and nonsustained ventricular tachycardia, respectively. Seventy-six (14.2%) individuals reached the primary end point (52 [68%] end-stage heart failure events, 24 [32%] malignant ventricular arrhythmia events). Malignant ventricular arrhythmia end points most commonly occurred in patients with severe LVSD. Male sex (hazard ratio, 1.89 [95% CI, 1.04-3.44]; P=0.04) and left ventricular ejection fraction (per 10% decrement from left ventricular ejection fraction, 50%; hazard ratio, 1.63 [95% CI, 1.30-2.04]; P<0.001) were independent predictors of the primary end point. Two hundred seven of 300 (69%) patients with LVSD had evidence of left ventricular reverse remodeling. In a subgroup of 29 of 74 (39%) patients with initial left ventricular reverse remodeling, there was a subsequent left ventricular ejection fraction decrement. TTNtv location was not associated with statistically significant differences in baseline clinical characteristics, left ventricular reverse remodeling, or outcomes on multivariable analysis (P=0.07).

CONCLUSIONS

TTNtv is characterized by frequent arrhythmia, but malignant ventricular arrhythmias are most commonly associated with severe LVSD. Male sex and LVSD are independent predictors of outcomes. Mutation location does not impact clinical phenotype or outcomes.

Hsa_circ_0002320: a novel clinical biomarker for colorectal cancer prognosis

A great many circular RNAs (circRNAs) exist in different types of mammalian cells. Previous studies have verified that a low level of hsa_circ_0002320 is present in gastric cancer and that it might represent a good prognostic indicator. However, its value in colorectal cancer (CRC) is unclear. The aim of this research was to explore the value of hsa_circ_0002320 as a potential diagnostic biomarker for CRC prognosis.Plasma samples, CRC tissues, and adjacent normal tissues were obtained from 50 patients with CRC, before any treatment, and 100 plasma samples were acquired from healthy individuals. Hsa_circ_0002320 levels in these samples were analyzed by reverse transcription-quantitative polymerase chain reaction. Correlations between hsa_circ_0002320, clinicopathological characteristics, and overall survival (OS) of CRC patients were also investigated. Receiver-operating characteristic (ROC) curve analysis was used to assess the value of hsa_circ_0002320 for CRC diagnosis. Finally, a bioinformatics analysis was performed to verify the effect of hsa_circ_0002320 on CRC prognosis.Expression levels of hsa_circ_0002320 were significantly decreased in CRC plasma (P < .05). The expression level of hsa_circ_0002320 was significantly correlated with OS time (P < .05). Higher hsa_circ_0002320 reflected significantly greater OS; the HR of high hsa_circ_0002320 was 0.161 (95% CI, 0.066-0.393; P = .000). The area under the ROC curve of hsa_circ_0002320 in CRC was 0.823, which was higher than for the carcinoembryogenic antigen (area under the curve = 0.764). Kaplan-Meier analysis showed that CRC patients with low expression of hsa_circ_0002320 exhibited poorer OS times than those with high expression.Hsa_circ_0002320 could be a novel, noninvasive diagnostic blood biomarker for CRC prognosis.

Functional Consequences of PDK4 Deficiency in Doberman Pinscher Fibroblasts

A splice site mutation in the canine pyruvate dehydrogenase kinase 4 (PDK4) gene has been shown to be associated with the development of dilated cardiomyopathy (DCM) in Doberman Pinchers (DPs). Subsequent studies have successfully demonstrated the use of dermal fibroblasts isolated from DPs as models for PDK4 deficiency and have shown activation of the intrinsic (mitochondrial mediated) apoptosis pathway in these cells under starvation conditions. For this study, we sought to further explore the functional consequences of PDK4 deficiency in DP fibroblasts representing PDK4^wt/wt, PDK4^wt/del, and PDK4^del/del genotypes. Our results show that starvation conditions cause increased perinuclear localization of mitochondria and decreased cell proliferation, altered expression levels of pyruvate dehydrogenase phosphatase (PDP) and pyruvate dehydrogenase (PDH), dramatically increased PDH activity, and an impaired response to mitochondrial stress in affected cells. In sum, these results show the broad impact of PDK4 deficiency and reveal mechanistic pathways used by these cells in an attempt to compensate for the condition. Our data help to elucidate the mechanisms at play in this extremely prevalent DP disorder and provide further support demonstrating the general importance of metabolic flexibility in cell health.

Emerging role of microRNAs in dilated cardiomyopathy: evidence regarding etiology

Dilated cardiomyopathy (DCM) is a heart muscle disease characterized by ventricular dilation and systolic dysfunction in the absence of abnormal loading conditions or coronary artery disease. This cardiac disorder is a major health problem due to its high prevalence, morbidity, and mortality. DCM is a complex disease with a common phenotype but heterogeneous pathological mechanisms. Early etiological diagnosis and prognosis stratification is crucial for the clinical management of the patient. Advances in imaging technology and genetic tests have provided useful tools for clinical practice. Nevertheless, the assessment of the disease remains challenging. Novel noninvasive indicators are still needed to assist in decision-making. microRNAs (miRNAs), a group of small noncoding RNAs, have been identified as key mediators of cell biology. They are found in a stable form in body fluids and their concentration is altered in response to stress. Previous research has suggested that the miRNA signature constitutes a novel source of noninvasive biomarkers for a wide array of cardiovascular diseases. Specifically, several studies have reported the potential role of miRNAs as clinical indicators among the etiologies of DCM. However, this field has not been reviewed in detail. Here, we summarize the evidence of intracellular and circulating miRNAs in DCM and their usefulness in the development of novel diagnostic, prognostic and therapeutic approaches, with a focus on DCM etiology. Although the findings are still preliminary, due to methodological and technical limitations and the lack of robust population-based studies, miRNAs constitute a promising tool to assist in the clinical management of DCM.

Differential expression of circulating miRNAs as a novel tool to assess BAG3-associated familial dilated cardiomyopathy

A new familial dilated cardiomyopathy (FDCM) was found related to mutations in BAG3 gene. MicroRNAs (miRNAs) represent new targets of FDCM, although no studies have assessed clinical association between Bcl2-associated athanogene 3 (BAG3)-related DCM and miRNAs. Here, we studied whether a clinical association between BAG3-related FDCM and circulating miRNAs may have diagnostic and prognostic value in a small cohort of familial related individuals carrying a BAG3 mutation (BAG3+) and/or diagnosed of dilated cardiomyopathy (DCM) (DCM+). The analysis of 1759 circulating miRNAs showed significant differences between BAG3+ and BAG3- individuals for miRNAs mir-3191-3p, 6769b-3p, 1249-ep, 154-5p, 6855-5p, and 182-5p, while comparisons between BAG3+/DCM+ versus BAG3+/DCM- were restricted to miRNAs mir-154-5p, 6885-5p, and 182-5p, showing significant correlation with systolic and diastolic blood pressure, A wave, left atrium length, and left atrium area. Additionally, when stratified by gender and age, miRNAs were statistically correlated with critical parameters, including left ventricle ejection fraction (LVEF) and ventricular diameter, in women and young men. Likewise, 56% of BAG3+/DCM+, significantly co-expressed mir-154-5p and mir-182-5p, and a slight 4% did not express such combination, suggesting that co-expression of mir-154-5p and mir-182-5p may potentially show diagnostic value. Further studies will require long-term follow-up, and validation in larger populations.

Practical Aspects in Genetic Testing for Cardiomyopathies and Channelopathies

Genetic testing has an increasingly important role in the diagnosis and management of cardiac disorders, where it confirms the diagnosis, aids prognostication and risk stratification and guides treatment. A genetic diagnosis in the proband also enables clarification of the risk for family members by cascade testing. Genetics in cardiac disorders is complex where epigenetic and environmental factors might come into interplay. Incomplete penetrance and variable expressivity is also common. Genetic results in cardiac conditions are mostly probabilistic and should be interpreted with all available clinical information. With this complexity in cardiac genetics, testing is only indicated in patients with a strong suspicion of an inheritable cardiac disorder after a full clinical evaluation. In this review we discuss the genetics underlying the major cardiomyopathies and channelopathies, and the practical aspects of diagnosing these conditions in the laboratory.

Genetic deletion of the alamandine receptor MRGD leads to dilated cardiomyopathy in mice

We have recently described a new peptide of the renin-angiotensin system, alamandine, a derivative of angiotensin-(1–7). Mas-related G protein-coupled receptor member D (MrgD) was identified as its receptor. Although similar cardioprotective effects of alamandine to those of angiotensin-(1–7) have been described, the significance of this peptide in heart function is still elusive. We aimed to evaluate the functional role of the alamandine receptor MrgD in the heart using MrgD-deficient mice. MrgD was localized in cardiomyocytes by immunofluorescence using confocal microscopy. High-resolution echocardiography was performed in wild-type and MrgD-deficient mice (2 and 12 wk old) under isoflurane anesthesia. Standard B-mode images were obtained in the right and left parasternal long and short axes for morphological and functional assessment and evaluation of cardiac deformation. Additional heart function evaluation was performed using Langendorff isolated heart preparations and inotropic measurements of isolated cardiomyocytes. Immunofluorescence indicated that the MrgD receptor is expressed in cardiomyocytes, mainly in the membrane and perinuclear and nuclear regions. Echocardiography showed left ventricular remodeling and severe dysfunction in MrgD-deficient mice. Strikingly, MrgD-deficient mice presented a pronounced dilated cardiomyopathy with a marked decrease in systolic function. Echocardiographic changes were supported by the data obtained in isolated hearts and inotropic measurements in cardiomyocytes. Our data add new evidence for a major role for alamandine/MrgD in the heart. Furthermore, our results indicate that we have identified a new gene implicated in dilated cardiomyopathy, unveiling a new target for translational approaches aimed to treat heart diseases.

NEW & NOTEWORTHY The renin-angiotensin system is a key target for cardiovascular therapy. We have recently identified a new vasodepressor/cardioprotective angiotensin, alamandine. Here, we unmasked a key role for its receptor, Mas-related G protein-coupled receptor member D (MrgD), in heart function. The severe dilated cardiomyopathy observed in MrgD-deficient mice warrants clinical and preclinical studies to unveil its potential use in cardiovascular therapy.

Listen to this article’s corresponding podcast at https://ajpheart.podbean.com/e/mrgd-deficiency-leads-to-dilated-cardiomyopathy/ .

Should Primary Prevention ICDs Still Be Placed in Patients with Non-ischemic Cardiomyopathy? A Review of the Evidence

PURPOSE OF REVIEW

Recent evidence has suggested that implantable defibrillator (ICD) in non-ischemic cardiomyopathy (NICM) may not offer mortality benefit in the presence of guideline-directed medical therapy (GDMT) and cardiac resynchronization therapy (CRT).

RECENT FINDINGS

Despite significant benefits of GDMT and CRT, current evidence is derived from ICD trials that rely predominantly on reduced left ventricular ejection fraction alone (LVEF). The majority of patients with sudden cardiac death (SCD) have LVEF > 30% indicating that LVEF by itself is an inadequate predictor of SCD. The Danish study to assess the efficacy of ICD in patients with non-ischemic systolic heart failure on mortality (DANISH) highlights the importance of better risk stratifying NICM patients for ICD implantation. Assessment of life expectancy, comorbidities, presence of advanced heart failure, etiology of NICM, and the presence of myocardial fibrosis can help risk stratify ICD beyond LVEF. Genetics and biomarkers can be of further assistance in risk stratification.

Circular RNAs in Blood

Recent advances in RNA sequencing and bioinformatic analysis have allowed the development of a new research field: circular RNAs (circRNAs). These members of the non-coding transcriptome are generated by backsplicing, which results in a covalently closed, single-stranded RNA molecule. To date, thousands of circRNAs have been identified in different human cell types. CircRNAs are evolutionarily conserved, highly stable, cell-/developmental stage-specific and have longer half-lives compared with linear RNAs. Interestingly, different studies have demonstrated that circRNAs are abundantly expressed in the bloodstream. In this chapter, we review the current knowledge of circRNA biology in blood cells and the cell-free compartment, including extracellular vesicles. The potential clinical application of blood circRNAs in the biomarker and therapy fields is also discussed. Finally, perspectives for future studies are proposed.

Sudden death risk stratification in non-ischemic dilated cardiomyopathy using old and new tools: a clinical challenge

INTRODUCTION

Risk stratification for sudden cardiac death in non-ischemic dilated cardiomyopathy (NIDCM) remains a clinical challenge. Areas covered: Currently, left ventricular ejection fraction (LVEF), severity of heart failure symptoms according to NYHA classification, and morphology and duration of the QRS complex guide device management in these patients with implantation of a cardioverter defibrillator (ICD) and/or cardiac resynchronization therapy (CRT) devices. Recently, the results of a randomized trial stirred some controversy regarding the utility of ICD in NIDCM patients, however, a subsequent meta-analysis confirmed prior findings of the survival-prolonging benefit of device therapy. Newer risk markers, like late gadolinium enhancement in cardiac magnetic resonance imaging (CMR) detecting myocardial fibrosis, are encouraging in improving risk stratification in these patients. Furthermore, resurgence of an old tool, the electrophysiology study (EPS), and technical advances in genetics in identifying high-risk familial NIDCM, appear promising in this direction. Expert commentary: Based on old and new tools, a more individualized approach may be applied in NIDCM patients, whereby CMR, EPS and genetics may provide further guidance, particularly in patients with LVEF>35%. These issues are herein reviewed and a practical algorithm is proposed for risk stratification and device implantation in NIDCM patients with LVEF below and above 35%.