Inhibition of Ceramide Synthesis Attenuates Chronic Ethanol Induced Cardiotoxicity by Restoring Lysosomal Function and Reducing Necroptosis.

AIMS: Chronic alcohol misuse could cause alcoholic cardiomyopathy (ACM), and the specific mechanisms remained largely unknown. In this study, we aimed to explore the effects of endogenous ceramides on chronic ethanol-induced myocardial injury or cell loss (e.g. necroptosis). METHODS: We established chronic alcohol intoxication models in vivo (male C57BL/6 mice) and in vitro (H9c2 cardiomyoblasts). The ceramide profiles were analyzed in mice myocardium and cultured cardiomyocytes. Further research on the role of ceramides and underlying signaling pathways was carried out in H9c2 cells. RESULTS AND CONCLUSIONS: The ceramide profiles analysis revealed increased long and very long-chain ceramides in alcoholic myocardium and ethanol-treated cardiomyocytes. Next, we proved that endogenous ceramide inhibition could reduce necroptosis and alleviate cardiomyocytes injury as suggested by decreased levels of p-RIPK1, p-RIPK3 and p-MLKL proteins and cardiac injury factors expression. Furthermore, we found that lysosomal dysfunction also contributed to alcohol-induced cardiac damage and inhibiting ceramide biosynthesis could repaired this to some extent. Cells studies with exogenous C6 ceramide confirmed the pleotropic roles of ceramide in myocardial damage by causing both necroptosis and lysosomal dysfunction. Finally, our data suggested that lysosomal dysfunction could sensitize cardiomyocytes to induction of necroptosis due to the restriction on degradation of RIPK1/RIPK3 proteins. In conclusion, chronic ethanol treatment boosted myocardial ceramide synthesis in animal hearts and cultured cardiomyocytes. Moreover, ceramides exerted crucial roles in the intrinsic signaling pathways of alcohol-induced cardiotoxicity. Targeting ceramide biosynthesis to simultaneously attenuate necroptosis and lysosomal dysfunction might be a novel strategy for preventing alcoholic cardiotoxicity.

Comprehensive analysis of transcriptomics and metabolomics to understand chronic ethanol induced murine cardiotoxicity.

Alcohol abuse has attracted public attention and long-term alcohol exposure can lead to alcohol-featured non-ischemic dilated cardiomyopathy. However, the precise underlying mechanisms of alcoholic cardiomyopathy remain to be elucidated. This study aimed to comprehensively characterize alcohol abuse-mediated effects on downstream metabolites and genes transcription using a multi-omics strategy. We established chronic ethanol intoxication model in adult male C57BL/6 mice through 8 weeks of 95% alcohol vapor administration and performed metabolomics analysis, mRNA-seq and microRNA-seq analysis with myocardial tissues. Firstly, ethanol markedly induced ejection fraction reductions, cardiomyocyte hypertrophy, and myocardial fibrosis in mice with myocardial oxidative injury. In addition, the omics analysis identified a total of 166 differentially expressed metabolites (DEMs), 241 differentially expressed genes (DEGs) and 19 differentially expressed microRNAs (DEmiRNAs), respectively. The results highlighted that alcohol abuse mainly interfered with endogenous lipids, amino acids and nucleotides production and the relevant genes transcription in mice hearts. Based on KEGG database, the affected signaling pathways are primarily mapped to the antigen processing and presentation, regulation of actin cytoskeleton, AMPK signaling pathway, tyrosine metabolism and PPAR signaling pathway, etc. Furthermore, 9 hub genes related to oxidative stress from DEGs were selected based on function annotation, and potential alcoholic cardiotoxic oxidative stress biomarkers were determined through establishing PPI network and DEmiRNAs-DEGs cross-talk. Altogether, our data strongly supported the conclusion that ethanol abuse characteristically affected amino acid and energy metabolism, nucleotide metabolism and especially lipids metabolism in mice hearts, and underlined the values of lipids signaling and oxidative stress in the treatment strategies.

Diagnostic Value of PICP and PIIINP in Myocardial Fibrosis: A Systematic Review and Meta-analysis.

Myocardial fibrosis is the excessive accumulation of extracellular matrix (ECM) components such as collagen and fibronectin, and its clinical diagnosis is always with limitations. Recently, PICP and PIIINP have been reported by several studies as potential biomarkers for the diagnosis of myocardial fibrosis, however, no meta-analyses focusing on the diagnostic values of these biomarkers have been conducted. So, the present study aimed to investigate the clinical diagnostic value of PICP and PIIINP in myocardial fibrosis patients. Based on the inclusion criteria, 1130 records were identified from four databases, and 12 studies were included eventually after independent screening. All 12 studies were high quality with the Newcastle-Ottawa Quality Assessment Scale (NOS) values ≥7. The results of the present meta-analysis indicated that patients with myocardial fibrosis revealed significantly elevated serum PICP (standard mean difference [SMD] = 0.90, 95% confidence interval [95% CI] = 0.40 to 1.40) and PIIINP (SMD = 0.83, 95% CI = 0.04 to 1.23). Therefore, we believe that PICP and PIIINP could be used as potential auxiliary biomarkers in the clinical diagnosis of myocardial fibrosis. This article is protected by copyright. All rights reserved.

Ethanol potentiates mirtazapine-induced cardiotoxicity by inducing dysfunctional autophagy via HMGB1-dependent Akt/mTOR signaling pathway.

Previous surveys have revealed that mirtazapine (MIR), one of the most commonly prescribed antidepressants, is associated with a higher risk of adverse cardiac events compared with other newer antidepressants. Chronic ethanol (EtOH) abuse could also lead to myocardial injuries. Concerning the common comorbidity of major depression and alcohol dependence, combined consumption of MIR and EtOH might be prevalent in patients with depression, resulting in an additive or synergistic cardiotoxic effect. To this end, the present study evaluated cardiotoxicity induced by MIR-plus-EtOH in vivo (male C57BL/6J mice) and in vitro (H9c2 cardiomyoblasts), Further research on the role of autophagy and underlying signaling pathway were carried out in H9c2 cells. We found that EtOH exacerbated MIR-induced cardiotoxicity both in vivo and in vitro. Furthermore, EtOH significantly potentiated MIR-induced dysfunctional autophagy as reflected by upregulated protein levels of LC3-II, p62, Beclin1 and LAMP-1. Pharmacological inhibition of autophagy by 3-methyladenine alleviated MIR-plus-EtOH-induced myocardial injury. High mobility group box 1 (HMGB1) is a positive regulator of autophagy. In our work, HMGB1 knockdown decreased autophagosome accumulation and boosted viability in H9c2 cells. Additionally, HMGB1 blockage markedly upregulated p-Akt/Akt and p-mTOR/mTOR levels which were suppressed in MIR-plus-EtOH treated cells. In general, the present study demonstrates that EtOH potentiates MIR-induced cardiotoxicity which might be attributed to dysfunctional autophagy via inhibiting Akt/mTOR signaling pathway, while HMGB1 knockdown might contribute to improve autophagy flux.

Abnormally High Blood Acetaldehyde Concentrations Suggest Potential Postmortem Ethanol Generation.

Ethanol is one of the most commonly used and abused substances worldwide. Identifying whether the source of ethanol detected in corpses is antemortem ingestion or postmortem generation is especially important for determining the cause of death, which remains a vibrant field of research. During the synthesis of ethanol in the putrefaction process of corpses, other small molecules such as acetaldehyde and n-propanol could also be produced. According to our prospective statistical analysis based on authentic samples from forensic cases, it is rational to suspect ethanol generation after death when the concentration of acetaldehyde detected in blood exceeds 0.014 g/dL. Through in vitro simulation experiments, in addition to confirming that ethyl glucuronide and ethyl sulfate are the reliable biomarkers of antemortem ingestion of ethanol, we propose that acetaldehyde is far more sensitive than n-propanol as a potential marker in the blood of corpses for postmortem ethanol formation.