Inhibition of CYP2E1 attenuates chronic alcohol intake-induced myocardial contractile dysfunction and apoptosis

miR-92a-3p regulates ethanol-induced apoptosis in H9c2 cardiomyocytes

The role of miR-92a-3p in the ethanol-induced apoptosis of H9c2 cardiomyocytes remains unclear. In this study, we explored the role of miR-92a-3p in the ethanol-induced apoptosis of H9c2 cardiomyocytes and identified its target genes and signaling pathways. H9c2 cells were cultured with or without 100 mM ethanol for 24 h. The differential expression of miR-92a-3p was verified in H9c2 cells through reverse transcription-quantitative polymerase chain reaction (RT-qPCR). To manipulate the expression of miR-92a-3p, both a mimic and an inhibitor were transfected into H9c2 cells. An Annexin V-fluorescein isothiocyanate/propidium iodide apoptosis detection kit and apoptosis-related antibodies were used for apoptosis detection through flow cytometry and Western blotting, respectively. Target genes were verified through RT-qPCR, Western blotting, and double luciferase reporter gene assays. miR-92a-3p was significantly overexpressed in ethanol-stimulated H9c2 cardiomyocytes (P < 0.001). After ethanol stimulation, H9c2 myocardial cells exhibited increased apoptosis. The apoptosis rate was higher in the miR-92a-3p mimic group than in the control group. However, the apoptosis rate was lower in the miR-92a-3p inhibitor group than in the control group, indicating that miR-92a-3p promotes the ethanol-induced apoptosis of H9c2 myocardial cells. RT-qPCR and Western blotting revealed that the miR-92a-3p mimic and inhibitor significantly regulated the mRNA and protein expression levels of mitogen- and stress-activated protein kinase 2 and cyclic AMP-responsive element-binding protein 3-like protein 2 (CREB3L2), suggesting that miR-92a-3p promotes the apoptosis of H9c2 cardiomyocytes by inhibiting the MSK2/CREB/Bcl-2 pathway. Therefore, the apoptosis of H9c2 cardiomyocytes increases after ethanol stimulation, and miR-92a-3p can directly target MSK2 and CREB3L2, thereby promoting the ethanol-induced apoptosis of H9c2 myocardial cells.

Selective inhibition of the NLRP3 inflammasome protects against acute ethanol-induced cardiotoxicity in an FBXL2-dependent manner

Binge drinking exerts cardiac toxicity through various mechanisms, including oxidative stress and inflammation. NLRP3 inflammasomes possess both pro- and anti-inflammatory properties, although the role of NLRP3 in ethanol-induced cardiotoxicity remains unknown. This study is designed to examine the role of NLRP3 inflammasome in acute ethanol cardiotoxicity and the underlying mechanisms of action. Nine- to twelve-week-old adult male C57BL/6 mice are administered with ethanol (1.5 g/kg, twice daily, i.p.) for 3 days. A cohort of control and ethanol-challenged mice are treated with the NLRP3 inhibitor MCC950 (10 mg/kg/day, i.p., days 1 and 3). Myocardial geometry and function are monitored using echocardiography and cardiomyocyte edge-detection techniques. Levels of NLRP3 inflammasome, mitophagy and apoptosis are evaluated by western blot analysis and immunofluorescence techniques. Acute ethanol challenge results in abnormally higher cardiac systolic function, in conjunction with deteriorated cardiac diastolic function and cardiomyocyte contractile function. Levels of NLRP3 inflammasome and apoptosis are elevated, and mitophagy flux is blocked (elevated Pink1-Parkin and LC3B along with diminished p62 and Rab7) in mice receiving acute ethanol challenge. Although MCC950 does not elicit a notable effect on myocardial function, apoptosis or inflammasome activation in the absence of ethanol exposure, it effectively rescues acute ethanol cardiotoxicity, as manifested by restored myocardial and cardiomyocyte functional homeostasis, suppressed NLRP3 inflammasome activation and apoptosis, and improved mitophagy flux. Our data further suggest that FBXL2, an E3 ubiquitin ligase associated with mitochondrial homeostasis and mitophagy, is destabilized due to proteasomal degradation of caspase-1 by ethanol-induced hyperactivation of NLRP3-caspase-1 inflammasome signaling, resulting in mitochondrial injury and apoptosis. These findings denote a role for NLRP3 inflammasome in acute ethanol exposure-induced cardiotoxicity in an FBXL2-dependent manner and the therapeutic promise of targeting NLRP3 inflammasome for acute ethanol cardiotoxicity.

Alcohol Intake Provoked Cardiomyocyte Apoptosis Via Activating Calcium-Sensing Receptor and Increasing Endoplasmic Reticulum Stress and Cytosolic [Ca2+]i

BACKGROUND

Cardiomyocyte apoptosis plays an important role in alcoholic cardiac injury. However, the association between calcium-sensing receptor (CaSR) and alcohol-induced cardiomyocyte apoptosis remain unclear. Therefore, we investigated the role and its moleculer mechanism of CaSR in rat cardiomyocyte apoptosis induced by alcohol.

METHODS

Alcohol-induced cardiomyocyte apoptosis in vivo and in vitro model of rats were applied in this study. The expression of CaSR, endoplasmic reticulum stress markers and apoptosis were tested by immunohistological staining, western blot, TUNEL and flow cytometry, respectively. [Ca2+]i were detected by confocal laser scanning microscopy.

RESULTS

Compared with the control group, alcohol intake (AI) led to abnormal arrangements of cardiomyocytes and obvious increase of myocardial apoptosis. Moreover, AI also significantly upregulated protein expression of CaSR, GRP94, caspase-12 and CHOP. Alcohol induced apoptosis of cultured cardiomyocytes of rats in a dose-dependent way. Activation of CaSR markedly enhanced cardiomyocyte apoptosis and ERS induced by alcohol, ERS inducer also significantly increased cardiomyocyte apoptosis without activating CaSR. Furthermore, GdCl3 augmented alcohol-induced increase of [Ca2+]i in cardiomyocytes, which was attenuated by NPS2390 but not 4-PBA pre-treatment.

CONCLUSIONS

Alcohol could induce cardiomyocyte apoptosis in rats in vivo and in vitro, which was mediated probably via activating CaSR, and then ERS and the increase of the cytosolic [Ca2+]i. This provides a potential target for preventing cardiomyocyte apoptosis and cardiomyopathy induced by alochol.

Perioperative Concerns in the Patient with History of Alcohol Use

Alcohol use is common in patients presenting for surgery and can result in significant physiologic changes and postoperative complications. Anesthesia providers must be aware of the potential risks associated with alcohol consumption and take steps to minimize them. Perioperative management includes assessing patients for alcohol use, providing alcohol cessation interventions, adjusting the anesthetic plan according to the patient's alcohol use history, providing appropriate pain management strategies, and closely monitoring patients during and after surgery for signs of alcohol withdrawal.

Solid herbal extract of Primula veris L. improves morphofunctional condition of rats’ myocardium in chronic alcohol intoxicat

Background and aim

Chronic alcohol intoxication (CAI) induces heart damage. One of the promising ways of its treatment involves the administration of herbal medicinal products. The purpose of this study was to explore the effect of solid herbal extract of Primula veris L. (PVSHE) on the morphofunctional changes in rats' myocardium after CAI.

Experimental procedure

CAI was simulated for 24 weeks. Loading testing was used to assess the functional condition of the heart, the functional assessment of mitochondria was based on the polarographic determination of oxygen consumption rate and determination of the indices of lipid peroxidation and antioxidant enzymes activity. We performed a microscopic examination of the left ventricle following the standard protocol of histological processing and h&e staining.

Results and conclusion

PVSHE restricts the toxic effects of ethanol on the heart which was indicated by a higher rise in the rates of myocardial contraction (by an average of 3.9 times, P < 0.05) and relaxation (2.6 times under volume load, P < 0.05), LVP (by an average of 1.7 times, P < 0.05) and MISP (by an average of 1.5 times, P < 0.05). PVSHE caused an improvement in the functional state of rats' cardiac mitochondria exposed to CAI, which was demonstrated by on average 1.3-1.4 times (P < 0.05) as high RCR as compared to the control group. The histological examination of the myocardium of the animals treated with PVSHE showed the increase in the volume fraction of cardiac myocytes, and a 31.2% (P < 0.05) decline in the interstitial volume. Therefore, PVSHE has a protective effect on the heart after CAI.

Insulin resistance enhances binge ethanol-induced liver injury through promoting oxidative stress and up-regulation CYP2E1

Alcoholic liver disease (ALD) has caused a serious burden on public and personal health in crowd with ethanol abuse. The effects of insulin resistance (IR) on ALD and the mechanisms underlying these responses are still not well understood. In this study, we investigated the changes of liver injury, inflammation, apoptosis, mitochondrial dysfunction and CYP2E1 changes in liver of mice exposed to ethanol with IR or not. We found IR increased the sensitivity of liver injury in mice exposed to ethanol, manifested as the increase serum activities of AST and ALT, the accumulation of triglycerides, the deterioration of liver pathology and increase of inflammatory factors. IR also exacerbated apoptosis and mitochondrial dysfunction in liver of mice exposed to ethanol. The increase of oxidative stress and the decrease of antioxidant defense ability might be responsible for the sensitizing effects of IR on ethanol-induced liver injury, supported by the increase of MDA levels and the decline of GSH/GSSG, the inactivation of antioxidant enzymes SOD, GR through the inhibition of Nrf-2 pathway. The activation of CYP2E1 might be also involved in the sensitizing effects of IR on ethanol induced liver injury in mice. These results demonstrated that IR exhibited a significant pro-oxidative and pro-apoptosis effects to aggravate alcoholic liver injury. Our study helped us to better understand the sensitive role of IR on ALD and suggested that alcohol intake may be more harmful for people with IR.

Alcohol-Associated Tissue Injury: Current Views on Pathophysiological Mechanisms

At-risk alcohol use is a major contributor to the global health care burden and leads to preventable deaths and diseases including alcohol addiction, alcoholic liver disease, cardiovascular disease, diabetes, traumatic injuries, gastrointestinal diseases, cancers, and fetal alcohol syndrome. Excessive and frequent alcohol consumption has increasingly been linked to alcohol-associated tissue injury and pathophysiology, which have significant adverse effects on multiple organ systems. Extensive research in animal and in vitro models has elucidated the salient mechanisms involved in alcohol-induced tissue and organ injury. In some cases, these pathophysiological mechanisms are shared across organ systems. The major alcohol- and alcohol metabolite-mediated mechanisms include oxidative stress, inflammation and immunometabolic dysregulation, gut leak and dysbiosis, cell death, extracellular matrix remodeling, endoplasmic reticulum stress, mitochondrial dysfunction, and epigenomic modifications. These mechanisms are complex and interrelated, and determining the interplay among them will make it possible to identify how they synergistically or additively interact to cause alcohol-mediated multiorgan injury. In this article, we review the current understanding of pathophysiological mechanisms involved in alcohol-induced tissue injury.

Diallyl sulfide protects against dilated cardiomyopathy via inhibition of oxidative stress and apoptosis in mice

Cytochrome P450 family 2 subfamily E member 1 (CYP2E1) is a member of the cytochrome P450 enzyme family and catalyzes the metabolism of various substrates. CYP2E1 is upregulated in multiple heart diseases and causes damage mainly via the production of reactive oxygen species (ROS). In mice, increased CYP2E1 expression induces cardiac myocyte apoptosis, and knockdown of endogenous CYP2E1 can attenuate the pathological development of dilated cardiomyopathy (DCM). Nevertheless, targeted inhibition of CYP2E1 via the administration of drugs for the treatment of DCM remains elusive. Therefore, the present study aimed to investigate whether diallyl sulfide (DAS), a competitive inhibitor of CYP2E1, can be used to inhibit the development of the pathological process of DCM and identify its possible mechanism. Here, cTnT^R141W transgenic mice, which developed typical DCM phenotypes, were used. Following treatment with DAS for 6 weeks, echocardiography, histological analysis and molecular marker detection were conducted to investigate the DAS-induced improvement on myocardial function and morphology. Biochemical analysis, western blotting and TUNEL assays were used to detected ROS production and myocyte apoptosis. It was found that DAS improved the typical DCM phenotypes, including chamber dilation, wall thinning, fibrosis, poor myofibril organization and decreased ventricular blood ejection, as determined using echocardiographic and histopathological analyses. Furthermore, the regulatory mechanisms, including inhibition both of the oxidative stress levels and the mitochondria-dependent apoptosis pathways, were involved in the effects of DAS. In particular, DAS showed advantages in terms of improved chamber dilation and dysfunction in model mice, and the improvement occurred in the early stage of the treatment compared with enalaprilat, an angiotensin-converting enzyme inhibitor that has been widely used in the clinical treatment of DCM and HF. The current results demonstrated that DAS could protect against DCM via inhibition of oxidative stress and apoptosis. These findings also suggest that inhibition of CYP2E1 may be a valuable therapeutic strategy to control the development of heart diseases, especially those associated with CYP2E1 upregulation. Moreover, the development of DAS analogues with lower cytotoxicity and metabolic rate for CYP2E1 may be beneficial.

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.

Nebivolol Prevents Up-Regulation of Nox2/NADPH Oxidase and Lipoperoxidation in the Early Stages of Ethanol-Induced Cardiac Toxicity

Changes in redox state are described in the early stages of ethanol-induced cardiac toxicity. Here, we evaluated whether nebivolol would abrogate ethanol-induced redox imbalance in the heart. Male Wistar rats were treated with a solution of ethanol (20% v/v) for 3 weeks. Treatment with nebivolol (10 mg/kg/day; p.o. gavage) prevented the increase of both superoxide (O2•-) and thiobarbituric acid reactive substances (TBARS) in the left ventricle of rats chronically treated with ethanol. Neither ethanol nor nebivolol affected the expression of Nox4, p47phox, or Rac-1. Nebivolol prevented ethanol-induced increase of Nox2 expression in the left ventricle. Superoxide dismutase (SOD) activity as well as the concentration of reduced glutathione (GSH) was not altered by ethanol or nebivolol. Augmented catalase activity was detected in the left ventricle of both ethanol- and nebivolol-treated rats. Treatment with nebivolol, but not ethanol increased eNOS expression in the left ventricle. No changes in the activity of matrix metalloproteinase (MMP)2 or in the expressions of MMP2, MMP9, and tissue inhibitor metalloproteinase (TIMP)1 were detected after treatment with ethanol or nebivolol. However, ethanol increased the expression of TIMP2, and this response was prevented by nebivolol. Our results provided novel insights into the mechanisms underlying the early stages of the cardiac injury induced by ethanol consumption. We demonstrated that Nox2/NADPH oxidase-derived ROS play a role in ethanol-induced lipoperoxidation and that this response was prevented by nebivolol. In addition, we provided evidence that MMPs are not activated in the early stages of ethanol-induced cardiac toxicity.

Alcohol suppresses cardiovascular diurnal variations in male normotensive rats: Role of reduced PER2 expression and CYP2E1 hyperactivity in the heart

BACKGROUND AND AIMS

The molecular mechanism of the adverse effects of ethanol on diurnal cardiovascular regulation remains unknown. In separate studies, the cardiac circadian rhythm protein period-2 (PER2) confers cardioprotection and, in other organs, PER2 interaction with the ethanol-metabolizing enzyme CYP2E1 underlies, via heme oxygenase-1 (HO-1) upregulation, tissue injury/dysfunction. Here, we hypothesized that suppressed PER2 expression and elevated CYP2E1/HO-1 levels in the heart underlie the disrupted diurnal cardiovascular rhythm/function in alcohol-fed normotensive rats.

METHODS

In ethanol-fed (5%, w/v; 8 weeks) or isocaloric liquid diet-fed male rats, diurnal changes in blood pressure (BP), heart rate (HR), HR vagal variability index, root mean square of successive beat-to-beat differences in beat-interval duration (rMSSD), and cardiac function were measured by radiotelemetry and echocardiography followed by ex vivo molecular studies.

RESULTS

Radiotelemetry findings showed ethanol-evoked reductions in BP (during the dark cycle), rMSSD (during both cycles), and in diurnal differences in BP and rMSSD. Echocardiography findings revealed significant (p < 0.05) reductions in ejection fraction and fractional shortening (weeks 4-6) in the absence of cardiac remodeling (collagen content). Hearts of ethanol-fed rats exhibited higher (p < 0.05) CYP2E1 activity (50%) and HO-1 expression (63%), along with reduction (p < 0.05) in PER2 levels (29%), compared with the hearts of isocaloric diet-fed control rats.

CONCLUSIONS

Our novel findings implicate upregulations of CYP2E1/HO-1 and downregulation of the circadian rhythm cardioprotective protein PER2, in the heart, in the chronic deleterious diurnal cardiovascular effects of alcohol in male rats.

NO66 overexpression rescues ethanol-induced cell apoptosis in human AC16 cardiomyocytes by suppressing PTEN and activating the PI3K/Akt signaling

Previously, Nucleolar protein 66 (NO66) was reported to be closely associated with alcohol exposure-induced injury. However, the role of NO66 in alcohol-induced cytotoxicity remains unclear. In this study, we explored the potential effect and mechanism of NO66 on ethanol-induced apoptosis in human AC16 cardiomyocytes. The AC16 cell lines with NO66 and phosphatase and tensin homolog (PTEN) overexpression were constructed. Cell counting kit-8 (CCK-8), lactate dehydrogenase (LDH) assay, Annexin V-FITC/PI staining, and flow cytometry were used to evaluate the cell viability, membrane damage, and apoptosis, respectively. Quantitative real-time PCR (qRT-PCR) and western blot analysis were applied to measure mRNA and protein expression. The results showed that acute ethanol exposure markedly augmented cytotoxicity and reduced NO66 level in AC16 cardiomyocytes. Overexpression of NO66 partially reversed ethanol-induced apoptosis. NO66 upregulation reversed the decrease in phosphorylation of protein kinase B (Akt) and B-cell lymphoma-2/Bcl-2-associated x (Bcl-2/Bax) ratio and the increase in PTEN, p53, and caspase-3 activity induced by ethanol treatment. Meanwhile, the application of PI3K inhibitor (LY294002) and PTEN overexpression attenuated the inhibition efficiency of NO66 on cell apoptosis. In addition, PTEN overexpression weakened the effect of NO66 on PI3K/Akt activation, without affecting the level of NO66. Our data suggested that NO66 overexpression might play an anti-apoptotic role in ethanol-induced cell injury via reducing PTEN and upregulating the PI3K/Akt pathway.

ALDH2 protects against alcoholic cardiomyopathy through a mechanism involving the p38 MAPK/CREB pathway and local renin-angiotensin system inhibition in cardiomyocytes

BACKGROUND

Angiotensin II (Ang II) in the local cardiac renin-angiotensin system (RAS) is closely associated with alcoholic cardiomyopathy (ACM). Inhibition of local cardiac RAS has great significance in the treatment of ACM. Although aldehyde dehydrogenase 2 (ALDH2) has been demonstrated to protect against ACM through detoxification of aldehydes, the precise mechanisms are largely unknown. In the present study, we determined whether ALDH2 improved cardiac damage by inhibiting the local RAS in ACM and investigated the related regulatory mechanisms.

METHODS AND RESULTS

Adult male mice were fed with 5% ethanol or a control diet for 2months, with or without the ALDH2 activator Alda-1. Heavy ethanol consumption induced cardiac damage, increased angiotensinogen (AGT) and Ang II and decreased myocardial ALDH2 activity in hearts. ALDH2 activation improved ethanol-induced cardiac damage and decreased AGT and Ang II in hearts. In vitro, ALDH2 activation or overexpression decreased AGT and Ang II in cultured cardiomyocytes treated with 400mmol/L ethanol for 24h. Furthermore, p38 MAP kinase (p38 MAPK)/cyclic adenosine monophosphate response element-binding protein (CREB) pathway activation by ethanol increased AGT and Ang II in cardiomyocytes. In addition, ALDH2 activation or overexpression inhibited the p38 MAPK/CREB pathway leading to decreased AGT and Ang II in cardiomyocytes. We also found that p38 MAPK activation effectively mitigated Alda-1-decreased AGT and Ang II, the effect of which was reversed by inhibition of CREB.

CONCLUSIONS

ALDH2 decreased AGT and Ang II in the local cardiac RAS via inhibiting the p38 MAPK/CREB pathway in ACM, thus improving ethanol-induced cardiac damage.

Genetic Polymorphisms of Alcohol Metabolizing Enzymes and Alcohol Consumption are Associated With Asymptomatic Cardiac Remodeling and Subclinical Systolic Dysfunction in Large Community-Dwelling Asians

Aims

Excessive consumption of alcoholic beverages is associated with cardiac remodeling and cardiomyopathy. We examined the possible association of alcohol use, common Asian genetic variants in genes involved in alcohol metabolism, and cardiac structures/functions alterations.

Methods

A prospective, community-dwelling survey among individuals with available complete echocardiography examined the associations of alcohol use, cardiac structure/functions, and three common alcohol metabolizing genetic variants, including aldehyde dehydrogenase 2 (ALDH2), alcohol dehydrogenase 1B (ADH1B) and cytochrome P450 (CYP) isoform 2E1 (CYP2E1).

Results

Among 1577 participants (mean age: 53 ± 9, 59.7% female), we observed that in subjects with more frequent weekly ethanol intake showed greater left ventricle (LV) mass, more impaired diastolic functions, and reduced global longitudinal strain (GLS), systolic (SRs) and early diastolic strain rates (SRe) (P<0.05). After propensity matching for clinical confounders (n = 330:30 for frequent users and non-users), frequent alcohol use and subjects carrying ALDH2 (A/G or A/A), ADH1B (A/A) or CYP2E1(T/C or T/T) polymorphisms were all associated with worse GLSRs and GLSRe, with combined alcohol use and any given genetic variant aggravated these associations (all P < 0.05). Finally, we observed Gene-Gene synergistic effects on LV functional decline in frequent alcohol users by using linear mixed effect model (all interaction P < 0.05).

Conclusions

Among East Asians, even moderate alcohol consumption can confer subclinical adverse effects on cardiac systolic functions, which was most pronounced in subjects carrying common variants in alcohol metabolizing genes. These findings challenge the notion of beneficial influences of less heavy ethanol consumption on the heart, especially among East Asians.

Short summary

This study evaluated the association of level of alcohol consumption and genetic variants in genes involved in alcohol metabolism with changes in cardiac function in East Asians. Even moderate alcohol use conferred subclinical adverse effects on cardiac systolic functions, which were most pronounced in subjects carrying common alcohol metabolizing genes.

Kinetic characterizations of diallyl sulfide analogs for their novel role as CYP2E1 enzyme inhibitors

Diallyl sulfide (DAS), a selective inhibitor of CYP2E1, has shown protective effects against alcohol‐ and acetaminophen‐induced hepatotoxicity in many studies. However, DAS is also a CYP2E1 substrate that on metabolism produces toxic metabolites and causes cytotoxicity. The objective of this study was to find a potent DAS analog as a CYP2E1 inhibitor and has the characteristic of producing less toxic metabolites. We selected seven commercially available compounds that are similar to DAS (DAS analogs). First, we performed ligand‐CYP2E1 docking study to determine the binding mode and binding energy. The analysis suggested a relative potential for these DAS analogs as CYP2E1 inhibitor. We then performed a comprehensive inhibition kinetics of DAS analogs and determined the relative IC₅₀, K_i, and types of inhibition compared to that of DAS. The results showed that compared to DAS, diallyl ether and allyl methyl sulfide have lower K_i values (3.1 and 4.4 μmol/L, respectively, vs. 6.3 μmol/L for DAS) and IC₅₀ values (6.3 and 11.4 μmol/L, respectively, vs. 17.3 μmol/L for DAS). However, allyl methyl sulfide and thiophene showed similar inhibitory capacities to that of DAS, and four other DAS analogs showed lower potency than DAS. In conclusion, we have found relatively more potent inhibitors of CYP2E1, which have lower toxicity than DAS. These compounds can replace DAS not only as a tool for in vitro and in vivo studies that involve CYP2E1 inhibition, but also can lead the way for their use in preventing CYP2E1‐mediated hepatic toxicity of alcohol and acetaminophen.

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.

ASK family in cardiovascular biology and medicine

Cardiovascular disease is a major cause of death worldwide. Mitogen-activated protein kinase (MAPK) signal cascades signaling pathways play crucial roles in cardiovascular pathophysiology. Apoptosis signal-regulating kinase (ASK) family members ASK1, ASK2 and ASK3 are the key molecules in MAPK signal cascades and are activated by various stresses. ASK1 is the most extensively studied MAPKKK and is involved in regulation of the cellular functions such as cell survival, proliferation, inflammation and apoptosis. The current review focuses on the relationship between ASK1 and cardiovascular disease, while exploring the novel therapeutic strategies for cardiovascular disease involved in the ASK1 signal pathway.

Combined Catalase and ADH Inhibition Ameliorates Ethanol-Induced Myocardial Dysfunction Despite Causing Oxidative Stress in Conscious Female Rats

BACKGROUND

Ethanol (EtOH)-evoked oxidative stress, which contributes to myocardial dysfunction in proestrus rats, is mediated by increases in NADPH oxidase (Nox) activity, malondialdehyde (MDA), and ERK1/2 phosphorylation. Whether these biochemical responses, which are triggered by alcohol-derived acetaldehyde in noncardiac tissues, occur in proestrus rats' hearts remains unknown. Therefore, we elucidated the roles of alcohol dehydrogenase (ADH), cytochrome P4502E1 (CYP2E1), and catalase, which catalyze alcohol oxidation to acetaldehyde, in these alcohol-evoked biochemical and hemodynamic responses in proestrus rats.

METHODS

Conscious proestrus rats prepared for measurements of left ventricular (LV) function and blood pressure (BP) received EtOH (1.5 g/kg, intravenous [i.v.] infusion over 30 minutes) or saline 30 minutes after an ADH and CYP2E1 inhibitor, 4-methylpyrazole (4-MP) (82 mg/kg, intraperitoneal), a catalase inhibitor, 3-AT (0.5 g/kg, i.v.), their combination, or vehicle. LV function and BP were monitored for additional 60 minutes after EtOH or saline infusion before collecting the hearts for ex vivo measurements of LV reactive oxygen species (ROS), Nox activity, MDA, and ERK1/2 phosphorylation.

RESULTS

EtOH reduced LV function (dP/dt_max and LV developed pressure) and BP, and increased cardiac Nox activity, ROS and MDA levels, and ERK1/2 phosphorylation. Either inhibitor partially, and their combination significantly, attenuated these responses despite the substantially higher blood EtOH level, and the increased cardiac oxidative stress and reduced BP caused by 3-AT alone or with 4-MP. The inhibitors reduced cardiac MDA level and reversed EtOH effect on cardiac and plasma MDA.

CONCLUSIONS

EtOH oxidative metabolism plays a pivotal role in the EtOH-evoked LV oxidative stress and dysfunction in proestrus rats. Notably, catalase inhibition (3-AT) caused cardiac oxidative stress and hypotension.

Etiology of alcoholic cardiomyopathy: Mitochondria, oxidative stress and apoptosis

Putative mechanisms leading to the development of alcoholic cardiomyopathy (ACM) include the interrelated cellular processes of mitochondria metabolism, oxidative stress and apoptosis. As mitochondria fuel the constant energy demands of this continually contracting tissue, it is not surprising that alcohol-induced molecular changes in this organelle contribute to cardiac dysfunction and ACM. As the causal relationship of these processes with ACM has already been established, the primary objective of this review is to provide an update of the experimental findings to more completely understand the aforementioned mechanisms. Accordingly, recent data indicate that alcohol impairs mitochondria function assessed by membrane potential and respiratory chain activity. Indictors of oxidative stress including superoxide dismutase, glutathione metabolites and malondialdehyde are also adversely affected by alcohol oftentimes in a sex-dependent manner. Additionally, myocardial apoptosis is increased based on assessment of TUNEL staining and caspase activity. Recent work has also emerged linking alcohol-induced oxidative stress with apoptosis providing new insight on the codependence of these interrelated mechanisms in ACM. Attention is also given to methodological differences including the dose of alcohol, experimental model system and the use of males versus females to highlight inconsistencies and areas that would benefit from establishment of a consistent model.

Alcoholic Cardiomyopathy: Disrupted Protein Balance and Impaired Cardiomyocyte Contractility

Alcoholic cardiomyopathy (ACM) can develop after consumption of relatively large amounts of alcohol over time or from acute binge drinking. Of the many factors implicated in the etiology of ACM, chronic perturbation in protein balance has been strongly implicated. This review focused on recent contributions (since 2010) in the area of protein metabolism and cardiac function related to ACM. Data reviewed include that from in vitro and preclinical in vivo animal studies where alcohol or an oxidative metabolite was studied and outcome measures in either cardiomyocytes or whole heart pertaining to protein synthesis or degradation were reported. Additionally, studies on the contractile properties of cardiomyocytes were also included to link signal transduction with function. Methodological differences including the potential impact of sex, dosing, and duration/timing of alcohol administration are addressed. Acute and chronic alcohol consumption decreases cardiac protein synthesis and/or activation of proteins within the regulatory mammalian/mechanistic target of rapamycin complex pathway. Albeit limited, evidence suggests that myocardial protein degradation via the ubiquitin pathway is not altered, while autophagy may be enhanced in ACM. Alcohol impairs ex vivo cardiomyocyte contractility in relation to its metabolism and expression of proteins within the growth factor pathway. Dysregulation of protein metabolism, including the rate of protein synthesis and autophagy, may contribute to contractile deficits and is a hallmark feature of ACM meriting additional sex-inclusive, methodologically consistent studies.

Salvianolic acid B attenuates doxorubicin-induced ER stress by inhibiting TRPC3 and TRPC6 mediated Ca2+ overload in rat cardiomyocytes

Doxorubicin (DOX)-induced cardiotoxicity is a clinically complex syndrome that leads to significant pain to cancer survivors. Endoplasmic reticulum (ER) stress has been suggested to be an important contributor to myocardium dysfunction during this phenomenon. Our previous study proved that Salvianolic acid B (Sal B) protected against doxorubicin induced cardiac dysfunction by inhibiting ER stress and cardiomyocyte apoptosis. However, the underlying molecular mechanism is not yet clearly. In this study, we investigated the protective effect and mechanisms of Sal B againest DOX-induced cardiac injury and ER stress in vivo and in vitro. After pretreatment with Sal B (0.25, 0.5, 1mg/kg i.v.) for 7 days, male SD rats were intraperitoneally injected with a single dose of DOX (3mg/kg) every 2 days for three injections. The cardioprotective effect of Sal B was observed 2 weeks after the first administration. Adult rat ventricular myocytes were isolated and treated with Sal B (20μg/ml) for 6h and then exposed in DOX (1μm) for 4h. The cardiomyocyte contractility and the level of intracellular Ca²⁺ were determined. Sal B ameliorated DOX-induced apoptosis damage in heart tissues. In vitro studies showed that DOX induced adult rat ventricular myocytes contractile dysfunction and intracellular Ca²⁺ handling derangement, disrupted mitochondrial membrane potential, raised the level of ER stress related proteins. However, Sal B pretreatment suppressed all of these adverse effects of DOX. The effects of Sal B were closely related to the inhibition of transient receptor potential canonical (TRPC) channels, as characterized by inhibiting the expression of TRPC 3 and TRPC6. These results indicate that Sal B protects against DOX-induced cardiac apoptosis and ER stress via TRPC3 and TRPC6 inhibition.

Toxicological Implications of Mitochondrial Localization of CYP2E1

Cytochrome P450 2E1 (CYP2E1) metabolizes an extensive array of pollutants, drugs, and other small molecules, often resulting in bioactivation to reactive metabolites. Therefore, it is unsurprising that it has been the subject of decades of research publications and reviews. However, while CYP2E1 has historically been studied in the endoplasmic reticulum (erCYP2E1), active CYP2E1 is also present in mitochondria (mtCYP2E1). Relatively few studies have specifically focused on mtCYP2E1, but there is growing interest in this form of the enzyme as a driver in toxicological mechanisms given its activity and location. Many previous studies have linked total CYP2E1 to conditions that involve mitochondrial dysfunction (fasting, diabetes, non-alcoholic steatohepatitis, and obesity). Furthermore, a large number of reactive metabolites that are formed by CYP2E1 through metabolism of drugs and pollutants have been demonstrated to cause mitochondrial dysfunction. Finally, there appears to be significant inter-individual variability in targeting to the mitochondria, which could constitute a source of variability in individual response to exposures. This review discusses those outcomes, the biochemical properties and toxicological consequences of mtCYP2E1, and highlights important knowledge gaps and future directions. Overall, we feel that this exciting area of research is rich with new and important questions about the relationship between mtCYP2E1, mitochondrial dysfunction, and pathology.

Diallyl Sulfide: Potential Use in Novel Therapeutic Interventions in Alcohol, Drugs, and Disease Mediated Cellular Toxicity by Targeting Cytochrome P450 2E1

Diallyl sulfide (DAS) and other organosulfur compounds are chief constituents of garlic. These compounds have many health benefits, as they are very efficient in detoxifying natural agents. Therefore, these compounds may be useful for prevention/treatment of cancers. However, DAS has shown appreciable allergic reactions and toxicity, as they can also affect normal cells. Thus their use as in the prevention and treatment of cancer is limited. DAS is a selective inhibitor of cytochrome P450 2E1 (CYP2E1), which is known to metabolize many xenobiotics including alcohol and analgesic drugs in the liver. CYP2E1-mediated alcohol/drug metabolism produce reactive oxygen species and reactive metabolites, which damage DNA, protein, and lipid membranes, subsequently causing liver damage. Several groups have shown that DAS is not only capable of inhibiting alcohol- and drug-mediated cellular toxicities, but also HIV protein- and diabetes-mediated toxicities by selectively inhibiting CYP2E1 in various cell types. However, due to known DAS toxicities, its use as a treatment modality for alcohol/drug- and HIV/diabetes-mediated toxicity have only limited clinical relevance. Therefore, effort is being made to generate DAS analogs, which are potent and selective inhibitor of CYP2E1 and poor substrate of CYP2E1. This review summarizes current advances in the field of DAS, its anticancer properties, role as a CYP2E1 inhibitor, preventing agent of cellular toxicities from alcohol, analgesic drugs, xenobiotics, as well as, from diseases like HIV and diabetes. Finally, this review also provides insights toward developing novel DAS analogues for chemical intervention of many disease conditions by targeting CYP2E1 enzyme.

Tert-butylhydroquinone attenuates the ethanol-induced apoptosis of and activates the Nrf2 antioxidant defense pathway in H9c2 cardiomyocytes

Tert-butylhydroquinone (tBHQ), an inducer of nuclear factor erythroid 2-related factor 2 (Nrf2), has been demonstrated to attenuate oxidative stress-induced injury and the apoptosis of human neural stem cells and other cell types. However, whether tBHQ is able to exert a protective effect against oxidative stress and the apoptosis of cardiomyocytes has not yet been determined. Thus, the objective of the present study was to determine whether tBHQ protects H9c2 cardiomyocytes against ethanol-induced apoptosis. For this purpose, four sets of experiments were performed under standard culture conditions as follows: i) untreated control cells; ii) cell treatment with 200 mM ethanol; iii) cell treatment with 5 µM tBHQ; and iv) cell pre-treatment with 5 µM tBHQ for 24 h, followed by medium change and co-culture with 200 mM ethanol containing 5 µM tBHQ for a further 24 h. The viability of the cardiomyocytes was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The levels of intracellular reactive oxygen species (ROS) and apoptosis were assessed by flow cytometry. Protein expression was measured by western blot analysis, and Nrf2 nuclear localization was observed by immunofluorescence. Exposure to ethanol led to a decrease in the protein expression of Nrf2 and its downstream antioxidant enzymes, accompanied by an increase in ROS generation and in the apoptosis of H9c2 cells. Pre-treatment with tBHQ significantly prevented the H9c2 cells from undergoing ethanol-induced apoptosis. tBHQ also increased the expression of B-cell lymphoma-2 (Bcl-2), whereas Bcl-2-associated X protein (Bax) expression was decreased. tBHQ promoted Nrf2 nuclear localization and increased the expression of Nrf2, superoxide dismutase (SOD), catalase (CAT) and heme oxygenase-1 (HO-1), and simultaneously inhibited the ethanol-induced overproduction of intracellular ROS. Therefore, tBHQ confers protection against the ethanol-induced apoptosis of and activates the Nrf2 antioxidant pathway in H9c2 cardiomyocytes.

Alcohol effects on cardiac function

The consumption of ethanol can have both beneficial and detrimental effects on the function of the heart and cardiovascular system, depending on the amount consumed. Low-to-moderate amounts of ethanol intake are associated with improvements in cardiac function and vascular health. On the other hand, ethanol chronically consumed in large amounts acts as a toxin to the heart and vasculature. The cardiac injury produced by chronic alcohol abuse can progress to heart failure and eventual death. Furthermore, alcohol abuse may exacerbate preexisting heart conditions, such as hypertension and cardiomyopathy. This article focuses on the molecular mechanisms and pathophysiology of both the beneficial and detrimental cardiac effects of alcohol.

Drug-induced mitochondrial dysfunction and cardiotoxicity

Mitochondria has an essential role in myocardial tissue homeostasis; thus deterioration in mitochondrial function eventually leads to cardiomyocyte and endothelial cell death and consequent cardiovascular dysfunction. Several chemical compounds and drugs have been known to directly or indirectly modulate cardiac mitochondrial function, which can account both for the toxicological and pharmacological properties of these substances. In many cases, toxicity problems appear only in the presence of additional cardiovascular disease conditions or develop months/years following the exposure, making the diagnosis difficult. Cardiotoxic agents affecting mitochondria include several widely used anticancer drugs [anthracyclines (Doxorubicin/Adriamycin), cisplatin, trastuzumab (Herceptin), arsenic trioxide (Trisenox), mitoxantrone (Novantrone), imatinib (Gleevec), bevacizumab (Avastin), sunitinib (Sutent), and sorafenib (Nevaxar)], antiviral compound azidothymidine (AZT, Zidovudine) and several oral antidiabetics [e.g., rosiglitazone (Avandia)]. Illicit drugs such as alcohol, cocaine, methamphetamine, ecstasy, and synthetic cannabinoids (spice, K2) may also induce mitochondria-related cardiotoxicity. Mitochondrial toxicity develops due to various mechanisms involving interference with the mitochondrial respiratory chain (e.g., uncoupling) or inhibition of the important mitochondrial enzymes (oxidative phosphorylation, Szent-Györgyi-Krebs cycle, mitochondrial DNA replication, ADP/ATP translocator). The final phase of mitochondrial dysfunction induces loss of mitochondrial membrane potential and an increase in mitochondrial oxidative/nitrative stress, eventually culminating into cell death. This review aims to discuss the mechanisms of mitochondrion-mediated cardiotoxicity of commonly used drugs and some potential cardioprotective strategies to prevent these toxicities.

Translational Implications of the Alcohol-Metabolizing Enzymes, Including Cytochrome P450-2E1, in Alcoholic and Nonalcoholic Liver Disease

Fat accumulation (hepatic steatosis) in alcoholic and nonalcoholic fatty liver disease is a potentially pathologic condition which can progress to steatohepatitis (inflammation), fibrosis, cirrhosis, and carcinogenesis. Many clinically used drugs or some alternative medicine compounds are also known to cause drug-induced liver injury, which can further lead to fulminant liver failure and acute deaths in extreme cases. During liver disease process, certain cytochromes P450 such as the ethanol-inducible cytochrome P450-2E1 (CYP2E1) and CYP4A isozymes can be induced and/or activated by alcohol and/or high-fat diets and pathophysiological conditions such as fasting, obesity, and diabetes. Activation of these P450 isozymes, involved in the metabolism of ethanol, fatty acids, and various drugs, can produce reactive oxygen/nitrogen species directly and/or indirectly, contributing to oxidative modifications of DNA/RNA, proteins and lipids. In addition, aldehyde dehydrogenases including the mitochondrial low Km aldehyde dehydrogenase-2 (ALDH2), responsible for the metabolism of acetaldehyde and lipid aldehydes, can be inactivated by various hepatotoxic agents. These highly reactive acetaldehyde and lipid peroxides, accumulated due to ALDH2 suppression, can interact with cellular macromolecules DNA/RNA, lipids, and proteins, leading to suppression of their normal function, contributing to DNA mutations, endoplasmic reticulum stress, mitochondrial dysfunction, steatosis, and cell death. In this chapter, we specifically review the roles of the alcohol-metabolizing enzymes including the alcohol dehydrogenase, ALDH2, CYP2E1, and other enzymes in promoting liver disease. We also discuss translational research opportunities with natural and/or synthetic antioxidants, which can prevent or delay the onset of inflammation and liver disease.

Metabolic methanol: molecular pathways and physiological roles

Methanol has been historically considered an exogenous product that leads only to pathological changes in the human body when consumed. However, in normal, healthy individuals, methanol and its short-lived oxidized product, formaldehyde, are naturally occurring compounds whose functions and origins have received limited attention. There are several sources of human physiological methanol. Fruits, vegetables, and alcoholic beverages are likely the main sources of exogenous methanol in the healthy human body. Metabolic methanol may occur as a result of fermentation by gut bacteria and metabolic processes involving S-adenosyl methionine. Regardless of its source, low levels of methanol in the body are maintained by physiological and metabolic clearance mechanisms. Although human blood contains small amounts of methanol and formaldehyde, the content of these molecules increases sharply after receiving even methanol-free ethanol, indicating an endogenous source of the metabolic methanol present at low levels in the blood regulated by a cluster of genes. Recent studies of the pathogenesis of neurological disorders indicate metabolic formaldehyde as a putative causative agent. The detection of increased formaldehyde content in the blood of both neurological patients and the elderly indicates the important role of genetic and biochemical mechanisms of maintaining low levels of methanol and formaldehyde.

Assessment of affective and somatic signs of ethanol withdrawal in C57BL/6J mice using a short-term ethanol treatment

Alcohol is one of the most prevalent addictive substances in the world. Withdrawal symptoms result from abrupt cessation of alcohol consumption in habitual drinkers. The emergence of both affective and physical symptoms produces a state that promotes relapse. Mice provide a preclinical model that could be used to study alcohol dependence and withdrawal while controlling for both genetic and environmental variables. The use of a liquid ethanol diet offers a reliable method for the induction of alcohol dependence in mice, but this approach is impractical when conducting high-throughput pharmacological screens or when comparing multiple strains of genetically engineered mice. The goal of this study was to compare withdrawal-associated behaviors in mice chronically treated with a liquid ethanol diet vs. mice treated with a short-term ethanol treatment that consisted of daily ethanol injections containing the alcohol dehydrogenase inhibitor, 4-methylpyrazole. Twenty-four hours after ethanol treatment, mice were tested in the open field arena, the elevated plus maze, the marble burying test, or for changes in somatic signs during spontaneous ethanol withdrawal. Anxiety-like and compulsive-like behaviors, as well as physical signs, were all significantly elevated in mice undergoing withdrawal, regardless of the route of ethanol administration. Therefore, a short-term ethanol treatment can be utilized as a screening tool for testing genetic and pharmacological agents before investing in a more time-consuming ethanol treatment.

Alcoholic cardiomyopathy: pathophysiologic insights

Alcoholic cardiomyopathy (ACM) is a specific heart muscle disease found in individuals with a history of long-term heavy alcohol consumption. ACM is associated with a number of adverse histological, cellular, and structural changes within the myocardium. Several mechanisms are implicated in mediating the adverse effects of ethanol, including the generation of oxidative stress, apoptotic cell death, impaired mitochondrial bioenergetics/stress, derangements in fatty acid metabolism and transport, and accelerated protein catabolism. In this review, we discuss the evidence for such mechanisms and present the potential importance of drinking patterns, genetic susceptibility, nutritional factors, race, and sex. The purpose of this review is to provide a mechanistic paradigm for future research in the area of ACM.

Nongenomic effects of estrogen mediate the dose-related myocardial oxidative stress and dysfunction caused by acute ethanol in female rats

Acute ethanol lowers blood pressure (BP) and cardiac output in proestrus and after chronic estrogen (E2) replacement in ovariectomized (OVX) female rats. However, whether rapid nongenomic effects of estrogen mediate these hemodynamic effects of ethanol remains unanswered. To test this hypothesis, we investigated the effect of ethanol (0.5 or 1.5 g/kg iv) on left ventricular (LV) function and oxidative markers in OVX rats pretreated 30 min earlier with 1 μg/kg E2 (OVXE2) or vehicle (OVX) and in proestrus sham-operated (SO) rats. In SO rats, ethanol caused significant and dose-related reductions in BP, rate of rise in LV pressure (LV dP/dtmax), and LV developed pressure (LVDP). These effects of ethanol disappeared in OVX rats and were restored in OVXE2 rats, suggesting rapid estrogen receptor signaling mediates the detrimental effects of ethanol on LV function. Ex vivo studies revealed that the estrogen-dependent myocardial dysfunction caused by ethanol was coupled with higher LV 1) generation of reactive oxygen species (ROS), 2) expression of malondialdehyde and 4-hydroxynonenal protein adducts, 3) phosphorylation of protein kinase B (Akt) and extracellular signal-regulated kinases (ERK1/2), and 4) catalase activity. ERK1/2 inhibition by PD-98059 (1 mg/kg iv) abrogated the myocardial dysfunction, hypotension, and the elevation in myocardial ROS generation caused by ethanol. We conclude that rapid estrogen receptor signaling is implicated in cellular events that lead to the generation of aldehyde protein adducts and Akt/ERK1/2 phosphorylation, which ultimately mediate the estrogen-dependent LV oxidative stress and dysfunction caused by ethanol in female rats.