AIN-93 Diet as an Alternative Model to Lieber-DeCarli Diet for Alcoholic Cardiomyopathy

Plasma concentrations of peptide hormones: Unrealistic levels of vasopressin (AVP), oxytocin (OXT), and brain natriuretic peptide (BNP)

Hormones are specific molecules measured in biological fluids by elaborate analytical systems requiring meticulous attention. Variation between laboratories can be expected. However, recently published measurements of AVP, OXT, and BNP in human plasma under basal/control conditions include numbers which, between publications, vary by 100-10 000-fold. Generally, the methods descriptions are scant, at best, and provide no information about quality control measures. Clearly, two results describing the same basal hormone concentration by numbers three orders of magnitude apart are incongruent providing reason for concern. Basal concentrations of bioactive AVP, OXT, and BNP in human plasma are in the order of 1-10 pmol/L. Therefore, assay systems applied to plasma must be able to measure concentrations of less than 1 pmol/L with appropriate specificity and accuracy. Basal concentrations of AVP, OXT, and BNP above 100 pmol/L should be reconsidered, as such results do not reflect bioactive hormone levels in humans, rats, or mice. Any concentration above 1000 pmol/L is of concern because such levels of bioactive hormone may be seen only under extreme conditions, if at all.

Chronic ethanol exposure induces cardiac fibroblast transdifferentiation via ceramide accumulation and oxidative stress

AIMS

Excessive alcohol consumption is associated with cardiac dysfunction and the development of myocardial fibrosis. In this study, we aimed to investigate the direct impacts of ethanol on myocardial fibroblasts and elucidate the underlying mechanism responsible for chronic ethanol-induced myocardial fibrosis.

METHODS

Rat primary cardiac fibroblasts exposed to ethanol for 24 h and C57BL/6J mice fed on Lieber-DeCarli diet to establish an ethanol intoxication model in vitro and in vivo, respectively. Histological analyses, molecular biology techniques, and analytical chemistry methods were then conducted.

RESULTS AND CONCLUSION

In vivo and vitro experiments revealed that chronic ethanol exposure induced increased myocardial fibrosis and augmented the transdifferentiation of myocardial fibroblasts. Simultaneously, it elicited an upregulation in the production of long-chain and very-long-chain ceramides in cardiac fibroblasts. The excessive accumulation of ceramide leads to elevated levels of intracellular oxidative stress, culminating in the activation of TGF-β-SMAD3 signaling and the development of fibrosis. Intervention of these pathways with pharmacological inhibitors in vitro or in vivo inhibited fibrosis. In conclusion, ethanol increased ceramides and reactive oxygen species (ROS) in cardiac fibroblasts, resulting in the activation of TGF-β-SMAD3 signaling, transdifferentiation of fibroblasts, and myocardial fibrosis.

Myocardial Injury Caused by Chronic Alcohol Exposure—A Pilot Study Based on Proteomics

Chronic alcohol exposure can cause myocardial degenerative diseases, manifested as cardiac insufficiency, arrhythmia, etc. These are defined as alcoholic cardiomyopathy (ACM). Alcohol-mediated myocardial injury has previously been studied through metabolomics, and it has been proved to be involved in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway concerning unsaturated fatty acids biosynthesis and oxidative phosphorylation, which tentatively explored the mechanism of ACM induced by chronic drinking. To further study alcohol-induced myocardial injury, myocardial specimens from a previously successfully established mouse model of ACM were subjected to histological, echocardiographic, and proteomic analyses, and validated by real-time quantitative polymerase chain reaction (qPCR). Results of histopathology and echocardiography showed the hypertrophy of cardiomyocytes, the dilation of ventricles, and decreased cardiac function. Proteomic results, available via ProteomeXchange with identifier PXD032949, revealed 56 differentially expressed proteins (DEPs) were identified, which have the potential to be involved in the KEGG pathway related to fatty acid biosynthesis disorders, lipid metabolism disorders, oxidative stress, and, ultimately, in the development of dilated cardiomyopathy (DCM). The present study further elucidates the underlying effects of myocardial injury due to chronic alcohol intake, laying a foundation for further studies to clarify the potential mechanisms of ACM.

Polydatin attenuates chronic alcohol consumption-induced cardiomyopathy through a SIRT6-dependent mechanism

Polydatin has attracted much attention as a potential cardioprotective agent against ischemic heart disease and diabetic cardiomyopathy. However, the effect and mechanism of polydatin supplementation on alcoholic cardiomyopathy (ACM) are still unknown. This study aimed to determine the therapeutic effect of polydatin against ACM and to explore the molecular mechanisms with a focus on SIRT6-AMP-activated protein kinase (AMPK) signaling and mitochondrial function. The ACM model was established by feeding C57/BL6 mice with an ethanol Lieber-DeCarli diet for 12 weeks. The mice received polydatin (20 mg kg^-1) or vehicle treatment. We showed that polydatin treatment not only improved cardiac function but also reduced myocardial fibrosis and dynamin-related protein 1 (Drp-1)-mediated mitochondrial fission, and enhanced PTEN-induced putative kinase 1 (PINK1)-Parkin-dependent mitophagy in alcohol-treated myocardium. Importantly, these beneficial effects were mimicked by SIRT6 overexpression but abolished by the infection of recombinant serotype 9 adeno-associated virus (AAV9) carrying SIRT6-specific small hairpin RNA. Mechanistically, alcohol consumption induced a gradual decrease in the myocardial SIRT6 level, while polydatin effectively activated SIRT6-AMPK signaling and modulated mitochondrial dynamics and mitophagy, thus reducing oxidative stress damage and preserving mitochondrial function. In summary, these data present new information regarding the therapeutic actions of polydatin, suggesting that the activation of SIRT6 signaling may represent a new approach for tackling ACM-related cardiac dysfunction.

A Pilot Metabolomic Study on Myocardial Injury Caused by Chronic Alcohol Consumption-Alcoholic Cardiomyopathy

Chronic alcohol consumption leads to myocardial injury, ventricle dilation, and cardiac dysfunction, which is defined as alcoholic cardiomyopathy (ACM). To explore the induced myocardial injury and underlying mechanism of ACM, the Liber-DeCarli liquid diet was used to establish an animal model of ACM and histopathology, echocardiography, molecular biology, and metabolomics were employed. Hematoxylin-eosin and Masson's trichrome staining revealed disordered myocardial structure and local fibrosis in the ACM group. Echocardiography revealed thinning wall and dilation of the left ventricle and decreased cardiac function in the ACM group, with increased serum levels of brain natriuretic peptide (BNP) and expression of myocardial BNP mRNA measured through enzyme-linked immunosorbent assay and real-time quantitative polymerase chain reaction (PCR), respectively. Through metabolomic analysis of myocardium specimens, 297 differentially expressed metabolites were identified which were involved in KEGG pathways related to the biosynthesis of unsaturated fatty acids, vitamin digestion and absorption, oxidative phosphorylation, pentose phosphate, and purine and pyrimidine metabolism. The present study demonstrated chronic alcohol consumption caused disordered cardiomyocyte structure, thinning and dilation of the left ventricle, and decreased cardiac function. Metabolomic analysis of myocardium specimens and KEGG enrichment analysis further demonstrated that several differentially expressed metabolites and pathways were involved in the ACM group, which suggests potential causes of myocardial injury due to chronic alcohol exposure and provides insight for further research elucidating the underlying mechanisms of ACM.

Aerobic exercise attenuates the effects of ovariectomy and sedentarism on body composition and food intake in female rats

ABSTRACT Objective To evaluate the impact of low to moderate aerobic exercise and ovariectomy on body composition and food consumption in female rats. Methods Forty adult Wistar female rats (age: 23 weeks; body weight: 275.2±3.6g; mean±SEM) were divided into 4 groups (n=10): laparotomy-sedentary; laparotomy-exercised; ovariectomy-sedentary; and ovariectomy-exercised. The exercised groups were submitted to a treadmill running program (16m/min; 30min/day, 5 days/week), for 8 weeks. Body weight and food consumption were monitored during the experiment. Visceral fat and carcass water, protein, ash, fat and carbohydrate fractions were analyzed. Two-way ANOVA plus the Tukey’s post hoc test was used for comparisons and p<0.05 was considered significant. Results The ovariectomized (ovariectomy-sedentary+ovariectomy-exercised) and sedentary (laparotomy-sedentary+ovariectomy-sedentary) animals showed higher (p<0.05) weight gain, food consumption, food efficiency ratio and weight gain/body weight ratio than laparotomy animals (laparotomy-sedentary+laparotomy-exercised) and exercised (exercised laparotomy+exercised ovariectomy), respectively. The ovariectomized and sedentary animals showed higher (p<0.05) carcass weight, fat percentage and visceral fat than laparotomy and exercised rats, respectively. Conclusion Ovariectomy and physical inactivity increase obesogenic indicators, whereas regular aerobic exercise of low to moderate intensity attenuates these unfavorable effects in female rats.