Obg-like ATPase 1 Genetic Deletion Leads to Dilated Cardiomyopathy in Mice and Structural Changes in Drosophila Heart

Cardiomyopathy, disease of the heart muscle, is a significant contributor to heart failure. The pathogenesis of cardiomyopathy is multifactorial and involves genetic, environmental, and lifestyle factors. Identifying and characterizing novel genes that contribute to cardiac pathophysiology are crucial for understanding cardiomyopathy and effective therapies. In this study, we investigated the role of a novel gene, Obg-like ATPase 1 ( Ola1 ), in cardiac pathophysiology using a cardiac-specific knockout mouse model as well as a Drosophila model. Our previous work demonstrated that OLA1 modulates the hypertrophic response of cardiomyocytes through the GSK-beta/beta-catenin signaling pathway. Furthermore, recent studies have suggested that OLA1 plays a critical role in organismal growth and development. For example, Ola1 null mice exhibit increased heart size and growth retardation. It is not known, however, if loss of function for Ola1 leads to dilated cardiomyopathy. We generated cardiac-specific Ola1 knockout mice (OLA1-cKO) to evaluate the role of OLA1 in cardiac pathophysiology. We found that Ola1 -cKO in mice leads to dilated cardiomyopathy (DCM) and left ventricular (LV) dysfunction. These mice developed severe LV dilatation, thinning of the LV wall, reduced LV function, and, in some cases, ventricular wall rupture and death. In Drosophila, RNAi-mediated knock-down specifically in developing heart cells led to the change in the structure of pericardial cells from round to elongated, and abnormal heart function. This also caused significant growth reduction and pupal lethality. Thus, our findings suggest that OLA1 is critical for cardiac homeostasis and that its deficiency leads to dilated cardiomyopathy and dysfunction. Furthermore, our study highlights the potential of the Ola1 gene as a therapeutic target for dilated cardiomyopathy and heart failure.

Sex-based differences in the phenotypic expression and prognosis of idiopathic non-ischaemic cardiomyopathy: a cardiovascular magnetic resonance study

AIMS

We sought to characterize sex-related differences in cardiovascular magnetic resonance-based cardiovascular phenotypes and prognosis in patients with idiopathic non-ischaemic cardiomyopathy (NICM).

METHODS AND RESULTS

Patients with NICM enrolled in the Cardiovascular Imaging Registry of Calgary (CIROC) between 2015 and 2021 were identified. Z-score values for chamber volumes and function were calculated as standard deviation from mean values of 157 sex-matched healthy volunteers, ensuring reported differences were independent of known sex-dependencies. Patients were followed for the composite outcome of all-cause mortality, heart failure admission, or ventricular arrhythmia. A total of 747 patients were studied, 531 (71%) males. By Z-score values, females showed significantly higher left ventricular (LV) ejection fraction (EF; median difference 1 SD) and right ventricular (RV) EF (difference 0.6 SD) with greater LV mass (difference 2.1 SD; P < 0.01 for all) vs. males despite similar chamber volumes. Females had a significantly lower prevalence of mid-wall striae (MWS) fibrosis (22% vs. 34%; P < 0.001). Over a median follow-up of 4.7 years, 173 patients (23%) developed the composite outcome, with equal distribution in males and females. LV EF and MWS were significant independent predictors of the outcome (respective HR [95% CI] 0.97 [0.95-0.99] and 1.6 [1.2-2.3]; P = 0.003 and 0.005). There was no association of sex with the outcome.

CONCLUSION

In a large contemporary cohort, NICM was uniquely expressed in females vs. males. Despite similar chamber dilation, females demonstrated greater concentric remodelling, lower reductions in bi-ventricular function, and a lower burden of replacement fibrosis. Overall, their prognosis remained similar to male patients with NICM.

Impact of anemia on clinical outcomes in patients with acute heart failure: A systematic review and meta-analysis

Anemia and acute heart failure (AHF) frequently coexist. Several published studies have investigated the association of anemia with all-cause mortality and all-cause heart failure events in AHF patients, but their findings remain controversial. This study is intended to evaluate the relationship between anemia and AHF. We systematically searched PubMed, Medline, the Cochrane Library, Embase, and Elsevier's ScienceDirect databases until July 30, 2023, and selected prospective or retrospective cohort studies to evaluate anemia for AHF. A total of nine trials involving 29 587 AHF patients were eventually included. Pooled analyses demonstrated anemia is associated with a higher risk of all-cause heart failure event rate (OR: 1.82, 95% CI: 1.58-2.10, p < .01) and all-cause mortality, both for short-term (30 days) all-cause mortality (OR: 1.91, 95% CI: 1.31-2.79, p < .01) and long-term (1 year) all-cause mortality (OR: 1.72, 95% CI: 1.27-2.32, p < .01). The evidence from this meta-analysis suggested that anemia may be an independent risk factor for all-cause mortality and all-cause heart failure events in patients with AHF and might emphasize the importance of anemia correction before discharge.

[Research progress on the expression of the RBM20 gene in dilated cardiomyopathy]

Dilated cardiomyopathy (DCM) is a significant contributor to heart failure and can lead to life-threatening cardiovascular events at any stage. RNA-binding motif protein 20 (RBM20) gene mutation is known to be one of the causes of DCM. This mutation exhibits familial aggregation and is associated with arrhythmias, increasing the risk of sudden and early death. This article delves into the characteristics of the RBM20 gene, highlighting its role in regulating alternative splicing of the TTN gene and calcium/calmodulin-dependent protein kinase type II gene. Furthermore, the article provides a summary of treatment options available for DCM caused by RBM20 gene mutations, aiming to enhance clinicians' understanding of the RBM20 gene and provide new ideas for precision medicine treatment.

Trends in age and sex-specific dilated cardiomyopathy mortality in Italy, 2005-2017

AIMS

Data regarding the dilated cardiomyopathy (DCM)-related mortality and relative time trends in the Italian population remain scant. We sought to assess the DCM mortality rates and relative trends among the Italian population between 2005 and 2017.

METHODS

Annual death rates by sex and 5-year age group were extracted from the WHO global mortality database. The age-standardized mortality rates, with relative 95% confidence intervals (95% CIs), also stratified by sex, were calculated using the direct method. Joinpoint regression analyses were used to identify periods with statistically distinct log linear trends in DCM-related death rates. To calculate nationwide annual trends in DCM-related mortality, we assessed the average annual percentage change (AAPC) and relative 95% CIs.

RESULTS

In Italy, the DCM age-standardized annual mortality rate decreased from 4.99 (95% CI: 4.97-5.02) deaths per 100 000 to 2.51 (95% CI: 2.49-2.52) deaths per 100 000 population. Over the entire period, men had a higher DCM-related mortality rates than women. Moreover, the mortality rate increased with age, with a seemingly exponential distribution and showing a similar trend among men and women. Joinpoint regression analysis revealed a linear decrease in age-standardized DCM-related mortality from 2005 to 2017 [AAPC: -5.1% (95% CI: -5.9 to -4.3, P < 0.001)] in the entire Italian population. However, the decline was more pronounced among women [AAPC: -5.6 (95% CI: -6.4 to -4.8, P < 0.001)] compared with men [AAPC: -4.9 (95% CI: -5.8 to -4.1, P < 0.001)].

CONCLUSION

In Italy, the DCM-related mortality rates linearly declined from 2005 to 2017.

The Impact of Hypertension on Left Ventricular Function and Remodeling in Non-Ischemic Dilated Cardiomyopathy Patients: A 3.0 T MRI Study

BACKGROUND

Hypertension (HTN) is highly prevalent in non-ischemic dilated cardiomyopathy (NIDCM) patients, but little is known about its impact on left ventricular (LV) function and remodeling.

PURPOSE

To evaluate the effect of hypertension on LV function and remodeling in NIDCM patients.

STUDY TYPE

Retrospective.

POPULATION

Two-hundred and twelve NIDCM (HTN-) patients, 91 NIDCM (HTN+) patients, and 74 normal controls.

FIELD STRENGTH/SEQUENCE

3.0 T/bSSFP and phase-sensitive inversion recovery sequence.

ASSESSMENT

The LV geometry, myocardial strain, remodeling index (calculated as LVM/LVEDV), and LGE were measured and compared between groups. Determinants of LV strain and remodeling in NIDCM were investigated.

STATISTICAL TESTS

Student's t-test, Mann-Whitney U test, one-way analysis of variance, Kruskal-Wallis test, univariable and multivariable linear regression. A P value <0.05 was considered statistically significant.

RESULTS

Compared with normal controls, NIDCM patients had significantly higher LVEDV and significantly impaired LV strains, including LV global peak strain (PS) and peak systolic and diastolic strain rates in the radial, circumferential, and longitudinal directions. The NIDCM (HTN+) group had significantly decreased LV global longitudinal PS and peak diastolic strain rate (PDSR), and significantly increased LV mass index and remodeling index compared to the NIDCM (HTN-) group, despite there being no significant difference in ejection fraction (P = 0.241). The prevalence of LV LGE was significantly higher in the NIDCM (HTN+) group than in the NIDCM (HTN-) group. In multivariable regression models adjusted for potential confounders, hypertension was independently associated with LV global longitudinal PS and PDSR. Male sex, resting heart rate, and log(NT-proBNP) level were independent determinants of LV strains. Moreover, male sex, systolic and diastolic blood pressure, and presence of LGE were independent determinants of LV remodeling index.

DATA CONCLUSION

These findings suggest that coexistence of hypertension may further exacerbate the reduction in LV global strain and the aggravation of LV remodeling in NIDCM patients.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 3.

Machine learning and bioinformatics to identify 8 autophagy-related biomarkers and construct gene regulatory networks in dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a condition of impaired ventricular remodeling and systolic diastole that is often complicated by arrhythmias and heart failure with a poor prognosis. This study attempted to identify autophagy-related genes (ARGs) with diagnostic biomarkers of DCM using machine learning and bioinformatics approaches. Differential analysis of whole gene microarray data of DCM from the Gene Expression Omnibus (GEO) database was performed using the NetworkAnalyst 3.0 platform. Differentially expressed genes (DEGs) matching (|log2FoldChange ≥ 0.8, p value < 0.05|) were obtained in the GSE4172 dataset by merging ARGs from the autophagy gene libraries, HADb and HAMdb, to obtain autophagy-related differentially expressed genes (AR-DEGs) in DCM. The correlation analysis of AR-DEGs and their visualization were performed using R language. Gene Ontology (GO) enrichment analysis and combined multi-database pathway analysis were served by the Enrichr online enrichment analysis platform. We used machine learning to screen the diagnostic biomarkers of DCM. The transcription factors gene regulatory network was constructed by the JASPAR database of the NetworkAnalyst 3.0 platform. We also used the drug Signatures database (DSigDB) drug database of the Enrichr platform to screen the gene target drugs for DCM. Finally, we used the DisGeNET database to analyze the comorbidities associated with DCM. In the present study, we identified 23 AR-DEGs of DCM. Eight (PLEKHF1, HSPG2, HSF1, TRIM65, DICER1, VDAC1, BAD, TFEB) molecular markers of DCM were obtained by two machine learning algorithms. Transcription factors gene regulatory network was established. Finally, 10 gene-targeted drugs and complications for DCM were identified.