Alcoholic Cardiomyopathy: Disrupted Protein Balance and Impaired Cardiomyocyte Contractility

Alcohol consumption, alcohol use disorder and organ transplantation

In the present experience we have evaluated the link alcohol consumption/alcohol use disorder (AUD) and organ transplantation (OT) in order to provide adequate suggestions. The data used for the preparation of these recommendations are based on a detailed analysis of the scientific literature published before August 31, 2022 (Web of Science, Scopus, Google Scholar). Furthermore, in the process of developing this work, we consulted the guidelines/position papers of the scientific societies. With regard to the liver transplantation, there are position papers/guidelines that clearly define indications and contraindications for including the AUD patient in the transplant list. One of the major difficulties in this area is psychosocial assessment which can be influenced by stigma. To solve this problem, it is necessary to use objective tools. However, this assessment should be carried out after providing the patient and family adequate tools to be able to create or recreate reliable socio-family support. This behavior should also be used in the case of other OTs. For the latter, however, adequate guidelines must be created which at the moment do not exist or if there are, as in the case of heart transplantation, they are not sufficient. Even in the absence of obvious alcohol addiction, it is recommended to use alcohol use disorder identification test and to include the addiction specialist in the multidisciplinary transplant team. Besides, providing family members with the tools necessary to better support the patient is essential. They are patients with alcohol use disorder/ possible presence of psychopathological manifestations and alcohol-related pathology (cirrhosis, cardiomyopathy, liver-kidney disfunction, etc.). A cardiovascular and oncologic surveillance post-OT is recommended. For the selection of patients to be included in the list for non-LT (heart, lung, kidney, multivisceral, etc.) it is mandatory to include the diagnosis and treatment of AUDs in the guidelines. What has already been indicated for LT may be useful. Timing of alcoholic abstention in relation to clinical severity, optimal psychosocial activity, anticraving therapy in relation to the type of underlying disease and clinical severity. Close collaboration between scientific societies is required to better manage AUD patients who need OT.

Alpha-lipoic Acid Protects Against Chronic Alcohol Consumption-induced Cardiac Damage by the Aldehyde Dehydrogenase 2-associated PINK/Parkin Pathway

ABSTRACT

Chronic alcohol intake contributes to high mortality rates due to ethanol-induced cardiac hypertrophy and contractile dysfunction, which are accompanied by increased oxidative stress and disrupted mitophagy. Alpha-lipoic acid (α-LA), a well-known antioxidant, has been shown to protect against cardiac hypertrophy and inflammation. However, little is known about its role and mechanism in the treatment of alcoholic cardiomyopathy. Here, we evaluated the role of α-LA in alcohol-induced cardiac damage by feeding mice a 4.8% (v/v) alcohol diet with or without α-LA for 6 w. Our results suggested that chronic alcohol consumption increased mortality, blood alcohol concentrations, and serum aldehyde levels, but a-LA attenuated the elevations in mortality and aldehydes. Chronic alcohol intake also induced cardiac dysfunction, including enlarged left ventricles, reduced left ventricular ejection fraction, enhanced cardiomyocyte size, and increased serum levels of brain natriuretic peptide, lactate dehydrogenase, and creatine kinase myocardial isoenzyme. Moreover, alcohol intake led to the accumulation of collagen fiber and mitochondrial dysfunction, the effects of which were alleviated by α-LA. In addition, α-LA intake also prevented the increase in reactive oxygen species production and the decrease in mitochondrial number that were observed after alcohol consumption. Chronic alcohol exposure activated PINK1/Parkin-mediated mitophagy. These effects were diminished by α-LA intake by the activation of aldehyde dehydrogenase 2. Our data indicated that α-LA helps protect cardiac cells against the effects of chronic alcohol intake, likely by inhibiting PINK1/Parkin-related mitophagy through the activation of aldehyde dehydrogenase 2.

Chronic ethanol exposure induces mitochondrial dysfunction and alters gene expression and metabolism in human cardiac spheroids

BACKGROUND

Chronic alcohol consumption in adults can induce various cardiac toxicities such as arrhythmias, cardiomyopathy, and heart failure. Prenatal alcohol exposure can increase the risk of developing congenital heart defects among offspring. Understanding the molecular mechanisms underlying long-term alcohol exposure-induced cardiotoxicity can help guide the development of therapeutic strategies.

METHODS

Cardiomyocytes derived from human-induced pluripotent stem cells (hiPSC-CMs) were engineered into cardiac spheroids and treated with clinically relevant concentrations of ethanol (17 and 50 mM) for 5 weeks. The cells were then analyzed for changes in mitochondrial features, transcriptomic and metabolomic profiles, and integrated omics outcomes.

RESULTS

Following chronic ethanol treatment of hiPSC-CMs, a decrease in mitochondrial membrane potential and respiration and changes in expression of mitochondrial function-related genes were observed. RNA-sequencing analysis revealed changes in various metabolic processes, heart development, response to hypoxia, and extracellular matrix-related activities. Metabolomic analysis revealed dysregulation of energy metabolism and increased metabolites associated with the upregulation of inflammation. Integrated omics analysis further identified functional subclusters and revealed potentially affected pathways associated with cardiac toxicities.

CONCLUSION

Chronic ethanol treatment of hiPSC-CMs resulted in overall decreased mitochondrial function, increased glycolysis, disrupted fatty acid oxidation, and impaired cardiac structural development.

Deficiency in Beclin1 attenuates alcohol-induced cardiac dysfunction via inhibition of ferroptosis

BACKGROUND

Binge drinking leads to compromised mitochondrial integrity and contractile function in the heart although little effective remedy is readily available. Given the possible derangement of autophagy in ethanol-induced cardiac anomalies, this study was designed to examine involvement of Beclin1 in acute ethanol-induced cardiac contractile dysfunction, in any, and the impact of Beclin1 haploinsufficiency on ethanol cardiotoxicity with a focus on autophagy-related ferroptosis.

METHODS

WT and Beclin1 haploinsufficiency (BECN^+/-) mice were challenged with ethanol for one week (2 g/kg, i.p. on day 1, 3 and 7) prior to assessment of cardiac injury markers (LDH, CK-MB), cardiac geometry, contractile and mitochondrial integrity, oxidative stress, lipid peroxidation, apoptosis and ferroptosis.

RESULTS

Ethanol exposure compromised cardiac geometry and contractile function accompanied with upregulated Beclin1 and autophagy, mitochondrial injury, oxidative stress, lipid peroxidation and apoptosis, and ferroptosis (GPx4, SLC7A11, NCOA4). Although Beclin1 deficiency did not affect cardiac function in the absence of ethanol challenge, it alleviated ethanol-induced changes in cardiac injury biomarkers, cardiomyocyte area, interstitial fibrosis, echocardiographic and cardiomyocyte mechanical properties along with mitochondrial integrity, oxidative stress, lipid peroxidation, apoptosis and ferroptosis. Ethanol challenge evoked pronounced ferroptosis (downregulated GPx4, SLC7A11 and elevated NCOA4, lipid peroxidation), the effect was alleviated by Beclin1 haploinsufficiency. Inhibition of ferroptosis using LIP-1 rescued ethanol-induced cardiac mechanical anomalies. In vitro study noted that ferroptosis induction using erastin abrogated Beclin1 haploinsufficiency-induced response against ethanol.

CONCLUSIONS

In sum, our data suggest that Beclin1 haploinsufficiency benefits acute ethanol challenge-induced myocardial remodeling and contractile dysfunction through ferroptosis-mediated manner.

Epigenetic modification in alcohol use disorder and alcoholic cardiomyopathy: From pathophysiology to therapeutic opportunities

Alcohol consumption prompts detrimental psychological, pathophysiological and health issues, representing one of the major causes of death worldwide. Alcohol use disorder (AUD), which is characterized by compulsive alcohol intake and loss of control over alcohol usage, arises from a complex interplay between genetic and environmental factors. More importantly, long-term abuse of alcohol is often tied with unfavorable cardiac remodeling and contractile alterations, a cadre of cardiac responses collectively known as alcoholic cardiomyopathy (ACM). Recent evidence has denoted a pivotal role for ethanol-triggered epigenetic modifications, the interface between genome and environmental cues, in the organismal and cellular responses to ethanol exposure. To-date, three major epigenetic mechanisms (DNA methylation, histone modifications, and RNA-based mechanisms) have been identified for the onset and development of AUD and ACM. Importantly, these epigenetic changes induced by alcohol may be detectable in the blood, thus offering diagnostic, therapeutic, and prognostic promises of epigenetic markers for AUD and alcoholic complications. In addition, several epigenetic drugs have shown efficacies in the management of alcohol abuse, loss of control for alcohol usage, relapse, drinking-related anxiety and behavior in withdrawal. In this context, medications targeting epigenetic modifications may hold promises for pharmaceutical management of AUD and ACM.

Alcohol Use Disorders and Their Harmful Effects on the Contractility of Skeletal, Cardiac and Smooth Muscles

Alcohol misuse has deleterious effects on personal health, family, societal units, and global economies. Moreover, alcohol misuse usually leads to several diseases and conditions, including alcoholism, which is a chronic condition and a form of addiction. Alcohol misuse, whether as acute intoxication or alcoholism, adversely affects skeletal, cardiac and/or smooth muscle contraction. Ethanol (ethyl alcohol) is the main effector of alcohol-induced dysregulation of muscle contractility, regardless of alcoholic beverage type or the ethanol metabolite (with acetaldehyde being a notable exception). Ethanol, however, is a simple and "promiscuous" ligand that affects many targets to mediate a single biological effect. In this review, we firstly summarize the processes of excitation-contraction coupling and calcium homeostasis which are critical for the regulation of contractility in all muscle types. Secondly, we present the effects of acute and chronic alcohol exposure on the contractility of skeletal, cardiac, and vascular/ nonvascular smooth muscles. Distinctions are made between in vivo and in vitro experiments, intoxicating vs. sub-intoxicating ethanol levels, and human subjects vs. animal models. The differential effects of alcohol on biological sexes are also examined. Lastly, we show that alcohol-mediated disruption of muscle contractility, involves a wide variety of molecular players, including contractile proteins, their regulatory factors, membrane ion channels and pumps, and several signaling molecules. Clear identification of these molecular players constitutes a first step for a rationale design of pharmacotherapeutics to prevent, ameliorate and/or reverse the negative effects of alcohol on muscle contractility.

The alcohol-induced cardiomyopathy: A cardiovascular magnetic resonance characterization

BACKGROUND

Alcoholic cardiomyopathy(ACM) is part of the non-ischaemic dilated cardiomyopathy(NI-DCM) spectrum. Little is known about cardiovascular magnetic resonance(CMR) features in ACM patients. The aim of this study is to describe CMR findings and their prognostic impact in ACM patients.

METHODS

Consecutive ACM patients evaluated in five referral CMR centres from January 2005 to December 2018 were enrolled. CMR findings and their prognostic value were compared to idiopathic NI-DCM(iNI-DCM) patients. The main outcome was a composite of death/heart transplantation/life-threatening arrhythmias.

RESULTS

Overall 114 patients (52 with ACM and 62 with iNI-DCM) were included. ACM patients were more often males compared to iNI-DCM (90% vs 64%, respectively, p ≤ 0.001) and were characterized by a more pronounced biventricular adverse remodelling than iNI-DCM, i.e. lower LVEF (31 ± 12% vs 38 ± 11% respectively, p = 0.001) and larger left ventricular end-diastolic volume (116 ± 40 ml/m² vs 67 ± 20 ml/m² respectively, p < 0.001). Similarly to iNI-DCM, late gadolinium enhancement (LGE), mainly midwall, was present in more than 40% of ACM patients but, conversely, it was not associated with adverse outcome(p = 0.15). LGE localization was prevalently septal (87%) in ACM vs lateral in iNI-DCM(p < 0.05). Over a median follow-up of 42 months [Interquartile Range 24-68], adverse outcomes were similar in both groups(p = 0.67).

CONCLUSIONS

ACM represents a specific phenotype of NI-DCM, with severe morpho-functional features at the onset, but similar long-term outcomes compared to iNI-DCM. Despite the presence and pattern of distribution of LGE was comparable, ACM and iNI-DCM showed a different LGE localization, mostly septal in ACM and lateral in iNI-DCM, with different prognostic impact.

Astaxanthin attenuates alcoholic cardiomyopathy via inhibition of endoplasmic reticulum stress-mediated cardiac apoptosis

Chronic excessive ethanol consumption is associated with a high incidence of mortality due to ethanol-induced dilated cardiomyopathy, known as alcoholic cardiomyopathy (ACM). Mechanistic studies have demonstrated that apoptosis is key to the pathogenesis of ACM, and endoplasmic reticulum (ER) stress-associated apoptosis contributes to various ethanol-related diseases. Astaxanthin (AST) is a natural carotenoid that exerts an anti-ER stress effect. Importantly, strong evidence has shown that AST induces beneficial effects in various cardiovascular diseases. The present study aimed to investigate whether AST induces beneficial effects on ACM by suppressing cardiac apoptosis mediated by ER stress. We showed that after 2 months of chronic excessive ethanol consumption, mice displayed obvious cardiac dysfunction and morphological changes associated with increased fibrosis, oxidative stress, ER stress and apoptosis. However, cardiac damage above was attenuated in response to AST treatment. The cardioprotective effect of AST against ethanol toxicity was also confirmed in both H9c2 cells and primary cardiomyocytes, indicating that AST-induced protection directly targets cardiomyocytes. Both in vivo and in vitro studies showed that AST inhibited all three ER stress signaling pathways activated by ethanol. Furthermore, administration of the ER stress inhibitor sodium 4-phenylbutyrate (4-PBA) strongly suppressed ethanol-induced cardiomyocyte damage. Interestingly, AST induced further anti-apoptotic effects once co-treated with 4-PBA, indicating that AST protects the heart from ACM partially by attenuating ER stress, but other mechanisms still exist. This study highlights that administration of AST ablated chronic excessive ethanol consumption-induced cardiomyopathy by suppressing cardiac ER stress and subsequent apoptosis.

Pyroptotic cell death by exposure to 1-butanol in H9c2 cardiomyoblastoma cells

The aim of this study is to examine the molecular mechanism of cytotoxicity caused by direct exposure to short chain alcohol. We showed previously that exposing H9c2 cardiomyoblastoma cells to 150 mM 1-butanol results in cell death within 1 h through an intrinsic apoptotic pathway. The cell death is accompanied by plasma membrane blebbing and caspase-3 activation. Here we show that a higher concentration (200 mM) of 1-butanol, as well as prolonged exposure (3-6 h) to 150 mM 1-butanol, induces plasma membrane ballooning, a characteristic feature of pyroptosis. Although gasderminD (GSDMD) cleavage by caspase-1 was not observed, GSDME cleavage by caspase-3 was observed during exposure to 150 mM 1-butanol for 6 h. We conclude that pyroptotic cell death by 1-butanol in H9c2 cardiomyoblastoma cells should occur via the caspase-3-GSDME pathway, revealing that 1-butanol could induce not only apoptosis but also pyroptosis in the cells.

Characteristics of subjects with alcoholic cardiomyopathy and sudden cardiac death

OBJECTIVE

To study social and clinical characteristics of victims of sudden cardiac death (SCD) due to alcoholic cardiomyopathy (ACM).

METHODS

The study population comprised a subset of Fingesture cohort. All subjects were verified SCD victims determined to have ACM as cause of death in medico-legal autopsy between 1998 and 2017 in Northern Finland. The Finnish Population Register Centre provided SCD victims' last place of residence. Population data of residential area were obtained from Statistics Finland.

RESULTS

From a total of 5869 SCD victims in Fingesture cohort, in 290 victims the cause of SCD was ACM (4.9%; median age 56 (50-62) years; 83% males). In 64 (22.1%) victims, the diagnosis of cardiac disease was made prior to death and in 226 (77.9%) at autopsy. There were no significant differences in autopsy findings between victims with or without known cardiac diagnosis, but steatohepatitis (94.5%) and liver cirrhosis (64,5%) were common in both groups. Alcoholism was more often recorded in the known cardiac disease group (64.1% vs 47.3%, p=0.023). Majority were included in the working age population (ie, under 65 years) (54.8% and 53.1%, p=0.810). In high-income communities, 28.8% of ACM SCD victims had previously diagnosed cardiac disease, the proportion in the middle-income and low-income communities was 18.6% (p=0.05).

CONCLUSIONS

Majority of SCD victims due to ACM did not have previously diagnosed cardiac disease, but documented risk consumption of alcohol was common. This emphasises the importance of routine screening of alcohol consumption and signs of cardiomyopathy in heavy alcohol users in primary healthcare.

Role of Alcohol Oxidative Metabolism in Its Cardiovascular and Autonomic Effects

Several review articles have been published on the neurobehavioral actions of acetaldehyde and other ethanol metabolites as well as in major alcohol-related disorders such as cancer and liver and lung disease. However, very few reviews dealt with the role of alcohol metabolism in the adverse cardiac and autonomic effects of alcohol and their potential underlying mechanisms, particularly in vulnerable populations. In this chapter, following a brief overview of the dose-related favorable and adverse cardiovascular effects of alcohol, we discuss the role of ethanol metabolism in its adverse effects in the brainstem and heart. Notably, current knowledge dismisses a major role for acetaldehyde in the adverse autonomic and cardiac effects of alcohol because of its low tissue level in vivo. Contrary to these findings in men and male rodents, women and hypertensive individuals are more sensitive to the adverse cardiac effects of similar amounts of alcohol. To understand this discrepancy, we discuss the autonomic and cardiac effects of alcohol and its metabolite acetaldehyde in a model of hypertension, the spontaneously hypertensive rat (SHR) and female rats. We present evidence that enhanced catalase activity, which contributes to cardioprotection in hypertension (compensatory) and in the presence of estrogen (inherent), becomes detrimental due to catalase catalysis of alcohol metabolism to acetaldehyde. Noteworthy, studies in SHRs and in estrogen deprived or replete normotensive rats implicate acetaldehyde in triggering oxidative stress in autonomic nuclei and the heart via (i) the Akt/extracellular signal-regulated kinases (ERK)/nitric oxide synthase (NOS) cascade and (ii) estrogen receptor-alpha (ERα) mediation of the higher catalase activity, which generates higher ethanol-derived acetaldehyde in female heart. The latter is supported by the ability of ERα blockade or catalase inhibition to attenuate alcohol-evoked myocardial oxidative stress and dysfunction. More mechanistic studies are needed to further understand the mechanisms of this public health problem.

Acute alcohol prevents the refeeding-induced decrease in autophagy but does not alter the increased protein synthetic response in heart

Ethanol produces a state of anabolic resistance in skeletal muscle; however, whether the heart displays a similar defect is unknown. Hence, the purpose of this study was to determine the impact of acute ethanol administration on the major signal transduction pathways in the heart that are responsible for regulating the protein synthetic and degradative response to refeeding. Adult male C57Bl/6 mice were fasted for 12 h. Mice were then either refed normal rodent chow for 30 min or a separate group of mice remained food deprived prior to administration of 3-g/kg ethanol. Cardiac tissue and blood were collected 1 h thereafter and analyzed. Acute ethanol prevented the nutrient-induced stimulation of S6K1 phosphorylation in heart, but did not alter the phosphorylation of S6, eIF4B, and eEF2, known downstream substrates for this kinase. The refeeding-induced redistribution of eIF4E into the active eIF4F complex was also not changed by acute ethanol. Consistent with the above-mentioned changes in signaling proteins, ethanol did not impair the refeeding-induced increase in cardiac protein synthesis. Proteasome activity was not altered by alcohol and/or refeeding. In contrast, ethanol antagonized the refeeding-induced increase in ULK1 phosphorylation and p62 as well as the reduction in LC3B-II and Atg5/12 complex proteins. These data indicate that acute ethanol prevents the normally observed inhibition of autophagy seen after refeeding, while the mTOR-dependent increase in protein synthesis remains largely unaltered by alcohol.

Alcoholism: A Multi-Systemic Cellular Insult to Organs

Alcohol abuse can affect more than the heart and the liver. Many observers often do not appreciate the complex and differing aspects of alcohol's effects in pathophysiologies that have been reported in multiple organs. Chronic alcohol abuse is known to be associated with pathophysiological changes that often result in life-threatening clinical outcomes, e.g., breast and colon cancer, pancreatic disease, cirrhosis of the liver, diabetes, osteoporosis, arthritis, kidney disease, immune system dysfunction, hypertension, coronary artery disease, cardiomyopathy, and can be as far-reaching as to cause central nervous system disorders. In this review article, we will discuss the various organs impacted by alcohol abuse. The lack of clear guidelines on the amount and frequency of alcohol intake, complicated by personal demographics, make extrapolations to real-life practices at best difficult for public health policy-makers.

Role of autophagy and regulatory mechanisms in alcoholic cardiomyopathy

Alcoholism is accompanied with a high incidence of cardiac morbidity and mortality due to the development of alcoholic cardiomyopathy, manifested as dilation of one or both ventricles, reduced ventricular wall thickness, myofibrillary disarray, interstitial fibrosis, hypertrophy and contractile dysfunction. Several theories have been postulated for the etiology of alcoholic cardiomyopathy including ethanol/acetaldehyde toxicity, mitochondrial production of reactive oxygen species, oxidative injury, apoptosis, impaired myofilament Ca²⁺ sensitivity and protein synthesis, altered fatty acid extraction and deposition, as well as accelerated protein catabolism. In particular, buildup of long-lived or dysfunctional organelles has been reported to contribute to cardiac structural and functional damage following alcoholism. Removal of cell debris and defective organelles by autophagy is essential to the maintenance of cardiac homeostasis in physiological and pathological conditions. However, insufficient understanding is currently available with regards to the involvement of autophagy in the pathogenesis of alcoholic cardiomyopathy. This review summarizes the recent findings on the pathophysiological role of dysregulated autophagy in one set and development of alcoholic cardiomyopathy. A thorough understanding of how autophagy is affected in alcoholism, and subsequently, contributes to the pathogenesis of alcoholic heart injury, will offer therapeutic guidance towards the management of alcoholic cardiomyopathy.