Alcohol, signaling, and ECM turnover

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.

Pathophysiological Consequences of At-Risk Alcohol Use; Implications for Comorbidity Risk in Persons Living With Human Immunodeficiency Virus

At-risk alcohol use is a significant risk factor associated with multisystemic pathophysiological effects leading to multiorgan injury and contributing to 5.3% of all deaths worldwide. The alcohol-mediated cellular and molecular alterations are particularly salient in vulnerable populations, such as people living with HIV (PLWH), diminishing their physiological reserve, and accelerating the aging process. This review presents salient alcohol-associated mechanisms involved in exacerbation of cardiometabolic and neuropathological comorbidities and their implications in the context of HIV disease. The review integrates consideration of environmental factors, such as consumption of a Western diet and its interactions with alcohol-induced metabolic and neurocognitive dyshomeostasis. Major alcohol-mediated mechanisms that contribute to cardiometabolic comorbidity include impaired substrate utilization and storage, endothelial dysfunction, dysregulation of the renin-angiotensin-aldosterone system, and hypertension. Neuroinflammation and loss of neurotrophic support in vulnerable brain regions significantly contribute to alcohol-associated development of neurological deficits and alcohol use disorder risk. Collectively, evidence suggests that at-risk alcohol use exacerbates cardiometabolic and neurocognitive pathologies and accelerates biological aging leading to the development of geriatric comorbidities manifested as frailty in PLWH.

The influence of alcohol intake in myopia development or progression: The SUN cohort study

BACKGROUND

Myopia is a highly prevalent disorder, and one of the first causes of blindness. In turn, alcohol consumption has been shown to be a risk factor for many diseases and a main contributor to the global burden of disease. However, no studies have investigated the relationship between alcohol intake and myopia. Our aim was to prospectively assess the association between alcohol intake and the development or progression of myopia.

METHODS

In a Spanish dynamic prospective cohort (the SUN Project) we assessed 15,642 university graduates, recruited between 1999 and 2018 and followed up biennially through mailed questionnaires. Alcohol intake was assessed with a validated 136-item food frequency questionnaire. Development or progression of myopia was collected in subsequent questionnaires during follow-up every two years.

RESULTS

Alcohol intake was linearly and significantly associated with a higher risk of myopia development or progression: the OR for 10-year incidence/progression of myopia was 1.05, 95% CI 1.01-1.09 per each 10-grams increase in alcohol intake.

CONCLUSIONS

Alcohol consumption might lead to the development or progression of myopia, although confirmation is needed for the mechanisms through which this association may occur, thus further research is needed to verify these findings.

Metformin and Probiotics Interplay in Amelioration of Ethanol-Induced Oxidative Stress and Inflammatory Response in an In Vitro and In Vivo Model of Hepatic Injury

Alcohol-induced liver injury implicates inflammation and oxidative stress as important mediators. Despite rigorous research, there is still no Food and Drug Administration (FDA) approved therapies for any stage of alcoholic liver disease (ALD). Interestingly, metformin (Met) and several probiotic strains possess the potential of inhibiting alcoholic liver injury. Therefore, we investigated the effectiveness of combination therapy using a mixture of eight strains of lactic acid-producing bacteria, commercialized as Visbiome® (V) and Met in preventing the ethanol-induced hepatic injury using in vitro and in vivo models. Human HepG2 cells and male Wistar rats were exposed to ethanol and simultaneously treated with probiotic V or Met alone as well as in combination. Endoplasmic reticulum (ER) stress markers, inflammatory markers, lipid metabolism, reactive oxygen species (ROS) production, and oxidative stress were evaluated, using qRT-PCR, Oil red O staining, fluorimetry, and HPLC. In vitro, probiotic V and Met in combination prevented ethanol-induced cellular injury, ER stress, oxidative stress, and regulated lipid metabolism as well as inflammatory response in HepG2 cells. Probiotic V and Met also promoted macrophage polarization towards the M2 phenotype in ethanol-exposed RAW 264.7 macrophage cells. In vivo, combined administration of probiotic V and Met ameliorated the histopathological changes, inflammatory response, hepatic markers (liver enzymes), and lipid metabolism induced by ethanol. It also improved the antioxidant markers (HO-1 and Nrf-2), as seen by their protein levels in both HepG2 cells as well as liver tissue using ELISA. Hence, probiotic V may act, in addition to the Met, as an effective preventive treatment against ethanol-induced hepatic injury.

Magnesium, Calcium, Potassium, Sodium, Phosphorus, Selenium, Zinc, and Chromium Levels in Alcohol Use Disorder: A Review

Macronutrients and trace elements are important components of living tissues that have different metabolic properties and functions. Trace elements participate in the regulation of immunity through humoral and cellular mechanisms, nerve conduction, muscle spasms, membrane potential regulation as well as mitochondrial activity and enzymatic reactions. Excessive alcohol consumption disrupts the concentrations of crucial trace elements, also increasing the risk of enhanced oxidative stress and alcohol-related liver diseases. In this review, we present the status of selected macroelements and trace elements in the serum and plasma of people chronically consuming alcohol. Such knowledge helps to understand the mechanisms of chronic alcohol-use disorder and to progress and prevent withdrawal effects, also improving treatment strategies.

The Effects of Ethanol on the Heart: Alcoholic Cardiomyopathy

Alcoholic-dilated Cardiomyopathy (ACM) is the most prevalent form of ethanol-induced heart damage. Ethanol induces ACM in a dose-dependent manner, independently of nutrition, vitamin, or electrolyte disturbances. It has synergistic effects with other heart risk factors. ACM produces a progressive reduction in myocardial contractility and heart chamber dilatation, leading to heart failure episodes and arrhythmias. Pathologically, ethanol induces myocytolysis, apoptosis, and necrosis of myocytes, with repair mechanisms causing hypertrophy and interstitial fibrosis. Myocyte ethanol targets include changes in membrane composition, receptors, ion channels, intracellular [Ca2+] transients, and structural proteins, and disrupt sarcomere contractility. Cardiac remodeling tries to compensate for this damage, establishing a balance between aggression and defense mechanisms. The final process of ACM is the result of dosage and individual predisposition. The ACM prognosis depends on the degree of persistent ethanol intake. Abstinence is the preferred goal, although controlled drinking may still improve cardiac function. New strategies are addressed to decrease myocyte hypertrophy and interstitial fibrosis and try to improve myocyte regeneration, minimizing ethanol-related cardiac damage. Growth factors and cardiomyokines are relevant molecules that may modify this process. Cardiac transplantation is the final measure in end-stage ACM but is limited to those subjects able to achieve abstinence.

Circulating Endothelial Progenitor Cells Present an Inflammatory Phenotype and Function in Patients With Alcoholic Liver Cirrhosis

Background and Aim: Endothelial progenitor cells (EPCs) have been implicated in liver injury and repair. However, the phenotype and potential of these heterogenous EPCs remain elusive. In particular, their involvement in the pathogenesis of alcoholic liver cirrhosis (ALC) remains unclear. The current study extensively characterized the phenotype and functions of EPCs to understand their role in ALC pathogenesis. Methods: Circulating EPCs were identified as CD34+CD133+CD31+ cells by flow cytometer in ALC patients (n = 7) and healthy controls (HC, n = 7). A comprehensive characterization of circulating EPCs using more than 30 phenotype markers was performed by mass cytometer time of flight (CyTOF) in an independent cohort of age and gender matched ALC patients (n = 4) and controls (n = 5). Ex vivo cultures of circulating EPCs from ALC patients (n = 20) and controls (n = 18) were also tested for their functions, including colony formation, LDL uptake, lectin binding and cytokine secretion (ELISA). Results: Three distinct populations of circulating EPCs (CD34+CD133+CD31+) were identified, classified on their CD45 expression (negative: CD45-; intermediate: CD45int; high: CD45hi). CD45int and CD45hi EPCs significantly increased in ALC patients compared to controls (p-val = 0.006). CyTOF data showed that CD45hi EPCs were distinct from CD45- and CD45int EPCs, with higher expression of T cell and myeloid markers, including CD3, CD4, HLA-DR, and chemokine receptors, CCR2, CCR5, CCR7, and CX3CR1. Similar to circulating EPCs, percentage of CD45hiCD34+CD31+ EPCs in ex-vivo cultures from patients, were significantly higher compared to controls (p < 0.05). Cultured EPCs from patients also showed increased LDL uptake, lectin binding and release of TNF-alpha, RANTES, FGF-2, and VEGF. Conclusions: We report the first extensive characterization of circulating human EPCs with distinct EPC subtypes. Increase in CD45hi EPC subtype in ALC patients with enhanced functions, inflammatory cytokines and angiogenic mediators in patients suggests an inflammatory role for these cells in ALC.

YAP determines the cell fate of injured mouse hepatocytes in vivo

The presence of senescent, transformed or damaged cells can impair tissue function or lead to tumorigenesis; therefore, organisms have evolved quality control mechanisms to eliminate them. Here, we show that YAP activation induced by inactivation of the Hippo pathway specifically in damaged hepatocytes promotes their selective elimination by using in vivo mosaic analysis in mouse liver. These damaged hepatocytes migrate into the hepatic sinusoids, undergo apoptosis and are engulfed by Kupffer cells. In contrast, YAP activation in undamaged hepatocytes leads to proliferation. Cellular stresses such as ethanol that damage both liver sinusoidal endothelial cells and hepatocytes switch cell fate from proliferation to migration/apoptosis in the presence of activated YAP. This involves the activation of CDC42 and Rac that regulate cell migration. Thus, we suggest that YAP acts as a stress sensor that induces elimination of injured cells to maintain tissue and organ homeostasis.

Senescent and injured cells affect tissue functions and can drive tumorigenesis. Thus, efficient elimination of these cells is pivotal for tissue integrity. Here Miyamura et al. show that YAP acts as a cellular stress sensor and promotes the elimination of damaged cells to maintain tissue homeostasis.

Mast cell chymase affects the proliferation and metastasis of lung carcinoma cells in vitro

Metastasis of lung carcinoma cells is a major cause of organ failure and mortality of patients with lung cancer. Lung mast cells are a type of immune cell which reside in the respiratory mucosa. High numbers of mast cells are associated with the majority of common types of cancer; however, the effects of mast cells on cancer remain unclear. In the present study, the effects of mast cell chymase (MCC) on the proliferation and adhesion of the lung carcinoma cell lines A549 and H520 was investigated. After 24 h of treatment, the highest dose of MCC (50 mU/ml) decreased the proliferation rate of A549 and H520 cells, whereas the lowest dose of MCC (5 mU/ml) resulted in a small increase in the viability. A549 cells treated with MCC lost adhesion ability in a MCC dose-dependent manner; however, these detached cells were able to regrow when transferred to a fresh culture. The protein expression of epithelial (E-) cadherin, p53 and p21 in A549 lung carcinoma cells were detected by western blot analysis. The results of the present study revealed that, following 24 h of treatment, the expression level of E-cadherin was decreased, the p53 tumor suppressor protein was expressed in limited quantities and the expression of p21 was decreased. Zymography was used to examine the effects of MCC on the expression and activation of matrix metalloproteinase-9 (MMP-9) in A549 and H520 cells. The expression of MMP-9 in the two cell lines was time- and MCC dose-dependent. The results of the present study demonstrated that MCC stimulated lung carcinoma cell proliferation and adhesion, as well as regulated E-cadherin expression and the cell cycle, all of which are associated with cancer metastasis. Therefore, MCC may be a potential candidate for lung carcinoma therapy.

Association between Serum Selenium Concentrations and Levels of Proinflammatory and Profibrotic Cytokines-Interleukin-6 and Growth Differentiation Factor-15, in Patients with Alcoholic Liver Cirrhosis

According to some authors, serum selenium levels are strongly associated with the severity of liver diseases, including liver cirrhosis. The aim of this study was to determine the relationship between the concentration of selenium and pro-inflammatory and profibrotic cytokines-interleukin-6 (IL-6) and growth differentiation factor 15 (GDF-15) in patients with alcoholic liver cirrhosis. The parameters studied were determined in the serum of 99 patients with alcoholic liver cirrhosis divided based on the severity of disease according to the Child-Turcotte-Pugh criteria. In patients with liver cirrhosis, the serum selenium concentration was statistically lower, whereas serum IL-6 and GDF-15 concentrations were higher than those in the control group. Moreover, the concentration of selenium negatively correlated with the levels of GDF-15 and IL-6. The above results may indicate a role of selenium deficiency in the pathogenesis and progression of alcoholic liver disease.

Protective influence of hyaluronic acid on focal adhesion kinase activity in human skin fibroblasts exposed to ethanol

Aim

The aim of this study was to evaluate the effect of ethanol and hyaluronic acid (HA) on cell survival and apoptosis in cultured human skin fibroblasts. Regarding the mechanism of ethanol action on human skin fibroblasts, we investigated cell viability and apoptosis, expression of focal adhesion kinase (FAK), and the influence of HA on those processes.

Materials and methods

Studies were conducted in confluent human skin fibroblast cultures that were treated with 25 mM, 50 mM, and 100 mM ethanol or with ethanol and 500 µg/mL HA. Cell viability was examined using methyl thiazolyl tetrazolium (MTT) assay and NC-300 Nucleo-Counter. Imaging of the cells using a fluorescence microscope Pathway 855 was performed to measure FAK expression.

Results

Depending on the dosage, ethanol decreased cell viability and activated the process of apoptosis in human skin fibroblasts. HA prevented the negative influence of ethanol on cell viability and prevented apoptosis. The analysis of fluorescence imaging using BD Pathway 855 High-Content Bioimager showed the inhibition of FAK migration to the cell nucleus, depending on the increasing concentration of ethanol.

Conclusion

This study proves that downregulation of signaling pathway of FAK is involved in ethanol-induced apoptosis in human skin fibroblasts. The work also indicates a protective influence of HA on FAK activity in human skin fibroblasts exposed to ethanol.

New Treatment Strategies for Alcohol-Induced Heart Damage

High-dose alcohol misuse induces multiple noxious cardiac effects, including myocyte hypertrophy and necrosis, interstitial fibrosis, decreased ventricular contraction and ventricle enlargement. These effects produce diastolic and systolic ventricular dysfunction leading to congestive heart failure, arrhythmias and an increased death rate. There are multiple, dose-dependent, synchronic and synergistic mechanisms of alcohol-induced cardiac damage. Ethanol alters membrane permeability and composition, interferes with receptors and intracellular transients, induces oxidative, metabolic and energy damage, decreases protein synthesis, excitation-contraction coupling and increases cell apoptosis. In addition, ethanol decreases myocyte protective and repair mechanisms and their regeneration. Although there are diverse different strategies to directly target alcohol-induced heart damage, they are partially effective, and can only be used as support medication in a multidisciplinary approach. Alcohol abstinence is the preferred goal, but control drinking is useful in alcohol-addicted subjects not able to abstain. Correction of nutrition, ionic and vitamin deficiencies and control of alcohol-related systemic organ damage are compulsory. Recently, several growth factors (myostatin, IGF-1, leptin, ghrelin, miRNA, and ROCK inhibitors) and new cardiomyokines such as FGF21 have been described to regulate cardiac plasticity and decrease cardiac damage, improving cardiac repair mechanisms, and they are promising agents in this field. New potential therapeutic targets aim to control oxidative damage, myocyte hypertrophy, interstitial fibrosis and persistent apoptosis In addition, stem-cell therapy may improve myocyte regeneration. However, these strategies are not yet approved for clinical use.

Gut region-dependent alterations of nitrergic myenteric neurons after chronic alcohol consumption

Chronic alcohol abuse damages nearly every organ in the body. The harmful effects of ethanol on the brain, the liver and the pancreas are well documented. Although chronic alcohol consumption causes serious impairments also in the gastrointestinal tract like altered motility, mucosal damage, impaired absorption of nutrients and inflammation, the effects of chronically consumed ethanol on the enteric nervous system are less detailed. While the nitrergic myenteric neurons play an essential role in the regulation of gastrointestinal peristalsis, it was hypothesised, that these neurons are the first targets of consumed ethanol or its metabolites generated in the different gastrointestinal segments. To reinforce this hypothesis the effects of ethanol on the gastrointestinal tract was investigated in different rodent models with quantitative immunohistochemistry, in vivo and in vitro motility measurements, western blot analysis, evaluation of nitric oxide synthase enzyme activity and bio-imaging of nitric oxide synthesis. These results suggest that chronic alcohol consumption did not result significant neural loss, but primarily impaired the nitrergic pathways in gut region-dependent way leading to disturbed gastrointestinal motility. The gut segment-specific differences in the effects of chronic alcohol consumption highlight the significance the ethanol-induced neuronal microenvironment involving oxidative stress and intestinal microbiota.

Cardiovascular risks and benefits of moderate and heavy alcohol consumption

The heart and vascular system are susceptible to the harmful effects of alcohol. Alcohol is an active toxin that undergoes widespread diffusion throughout the body, causing multiple synchronous and synergistic effects. Alcohol consumption decreases myocardial contractility and induces arrhythmias and dilated cardiomyopathy, resulting in progressive cardiovascular dysfunction and structural damage. Alcohol, whether at binge doses or a high cumulative lifetime consumption-both of which should be discouraged-is clearly deleterious for the cardiovascular system, increasing the incidence of total and cardiovascular mortality, coronary and peripheral artery disease, heart failure, stroke, hypertension, dyslipidaemia, and diabetes mellitus. However, epidemiological, case-control studies and meta-analyses have shown a U-type bimodal relationship so that low-to-moderate alcohol consumption (particularly of wine or beer) is associated with a decrease in cardiovascular events and mortality, compared with abstention. Potential confounding influences-alcohol-dose quantification, tobacco use, diet, exercise, lifestyle, cancer risk, accidents, and dependence-can affect the results of studies of both low-dose and high-dose alcohol consumption. Mendelian methodological approaches have led to doubts regarding the beneficial cardiovascular effects of alcohol, and the overall balance of beneficial and detrimental effects should be considered when making individual and population-wide recommendations, as reductions in alcohol consumption should provide overall health benefits.

Delayed ethanol elimination and enhanced susceptibility to ethanol-induced hepatosteatosis after liver resection

AIM: To investigate ethanol-induced hepatic steatosis after liver resection and the mechanisms behind it.

METHODS: First, the preliminary examination was performed on 6 sham-operated (Sham) and 30 partial hepatectomy (PH) male Wistar rats (8-wk-old) to evaluate the recovery of the liver weight and liver function after liver resection. PH rats were sacrificed at the indicated time points (4, 8, and 12 h; 1, 3, and 7 d) after PH. Second, the time point for the beginning of the chronic ethanol exposure (1 wk after sham- or PH-operation) was determined based on the results of the preliminary examination. Finally, pair-feeding was performed with a controlled diet or with a 5-g/dL ethanol liquid diet for 28 d in another 35 age-matched male Wistar rats with a one-week recovery after undergoing a sham- (n = 15) or PH-operation (n = 20) to evaluate the ethanol-induced liver injury after liver resection. Hepatic steatosis, liver function, fatty acid synthase (Fas) gene expression level, the expression of lipid metabolism-associated enzyme regulator genes [sterol regulatory element binding protein (Srebp)-1 and peroxisome proliferator-activated receptor (Ppar)-α], the mediators that alter lipid metabolism [plasminogen activator (Pai)-1 gene expression level and tumor necrosis factor (Tnf)-α production], and hepatic class-1 alcohol dehydrogenase (Adh1)-associated ethanol elimination were investigated in the 4 groups based on histological, immunohistochemical, biochemical, Western blotting, reverse transcriptase chain reaction, and blood ethanol concentration analyses. The relevant gene expression levels, liver weight, and liver function were assessed before and 1 wk after surgery to determine the subject’s recovery from the liver resection using the rats that had been subjected to the preliminary examination.

RESULTS: In the PH rats, ethanol induced marked hepatic steatosis with impaired liver functioning, as evidenced by the accumulation of fatty droplets within the hepatocytes, the higher increases in their hepatic triglyceride and blood alanine aminotransferase and blood aspartate aminotransferase levels after the 28-d pair-feeding period. The Sham-ethanol rats, not the PH-ethanol rats, demonstrated the up-regulation of Srebp-1 and the down-regulation of Ppar-α mRNA expression levels after the 28-d pair-feeding period. The 28-d ethanol administration induced the up-regulation of Pai-1 gene expression level and an overproduction of TNF-α in the Sham and the PH rats; however, the effect was more significant in the PH rats. The PH-ethanol rats (n = 4) showed higher residual blood ethanol concentrations than did the Sham-ethanol rats (n = 6) after a 5-h fast (0.66 ± 0.4 mg/mL vs 0.2 ± 0.1 mg/mL, P < 0.05); these effects manifested without up-regulation of Adh1 gene expression, which was present in the Sham-ethanol group after the 28-d pair-feeding period. One week after the liver resection, the liver weight, function, the gene expression levels of Fas, Srebp-1, Ppar-α, Pai-1 and Tnf-α recovered; however, the Adh1 gene expression did not recover in rats.

CONCLUSION: Desensitization to post-hepatectomy ethanol treatment and slow recovery from PH in Adh1 gene expression enhanced the susceptibility to ethanol-induced hepatic steatosis after PH in rats.

Fibrogenesis in alcoholic liver disease

Alcoholic liver disease (ALD) is a major cause of morbidity and mortality worldwide. In developed countries, ALD is a major cause of end-stage liver disease that requires transplantation. The spectrum of ALD includes simple steatosis, alcoholic hepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Alcohol abstinence is the most effective therapy for ALD. However, targeted therapies are urgently needed for patients with severe ALD (i.e., alcoholic hepatitis) or those who do not abstain from alcohol. The lack of studies and the availability of animal models that do not reflect all the features of this disease in humans inhibit the development of new drugs for ALD. In ALD-associated fibrosis, hepatic stellate cells are the principal cell type responsible for extracellular matrix production. Although the mechanisms underlying fibrosis in ALD are largely similar to those observed in other chronic liver diseases, oxidative stress, methionine metabolism abnormalities, hepatocyte apoptosis, and endotoxin lipopolysaccharides that activate Kupffer cells may play unique roles in disease-related fibrogenesis. Lipogenesis during the early stages of ALD has recently been implicated as a risk factor for the progression of cirrhosis. Other topics include osteopontin, interleukin-1 signaling, and genetic polymorphism. In this review, we discuss the basic pathogenesis of ALD and focus on liver fibrogenesis.

Serum selenium levels and oxidative balance as differential markers in hepatic damage caused by alcohol

AIMS

Antioxidant system abnormalities have been associated with ethanol consumption. This study examines the effects of chronic ethanol consumption on oxidative balance, including selenium (Se) levels in alcoholic patients with or without liver disease, and if these measurements could be indicative of liver disease.

MAIN METHODS

Serum Se levels, antioxidant enzymes' activities, malondialdehyde (MDA) and protein carbonyl (PC) were determined in three groups of patients: alcoholics without liver disease, alcoholics with liver disease, and non-alcoholics with liver disease; and in healthy volunteers.

KEY FINDINGS

Serum Se levels were lower in alcoholic patients and in patients affected by liver disease and especially lower in the alcoholic liver disease group. These values were correlated with the activity of glutathione peroxidase (GPx), the antioxidant selenoprotein. The antioxidant activities of the glutathione reductase (GR) and superoxide dismutase (SOD) were also lower in the three non-healthy groups. However, GR activity decreased and SOD activity increased in the non-alcoholic liver disease group versus alcoholic groups. Higher concentrations of PC in serum were found in non-healthy groups and were higher in alcoholic patients who also showed higher MDA levels. The highest MDA and PC levels were found in the alcoholic liver disease group.

SIGNIFICANCE

We conclude that serum Se levels are drastically decreased in alcoholic liver disease patients, showing that this element has a direct correlation with GPx activity, and lipid oxidation, suggesting that the serum Se/MDA ratio could be an indicator of hepatic damage caused by alcohol consumption, and pointing to Se as a possible antioxidant therapy.

Gene network profiling before and after transplantation in alcoholic cirrhosis liver transplant recipients

The main objective of this study was to define a gene network profile network in liver transplant recipients with alcoholic cirrhosis before and after liver transplantation. Genes were selected from data obtained in a previous study of liver transplant recipients with alcoholic cirrhosis. Selected up-regulated genes were further validated by quantitative real-time polymerase chain reaction in different groups of liver transplant recipients with alcoholic cirrhosis (n=5). Selected genes up-regulated before transplantation were: TNFRSF9 (tumor necrosis factor [TNF] receptor superfamily, member 9); IL2RB (interleukin-2 receptor beta); BCL2L2 (BCL2-like 2); NOX5 (NADPH) oxidase, EF-hand calcium binding domain 5); PEX5 (peroxisomal biogenesis factor 5); PPARG (peroxisome proliferator-activated receptor gamma); NIBP (IKK2 binding protein); NKIRAS2 (NFKappaBeta inhibitor interacting Ras-like 2); IL4 (interleukin-4); IL-4R (interleukin 4 receptor); ADH1A (alcohol dehydrogenase 1A, class 1); ALDH1L1 (aldehyde dehydrogenase 1 family, member L1); MPO (myeloperoxidase); NPPA (natriuretic peptide precursor A); BCL2A1 (BCL2-related protein A1); GADD45A (growth arrest and DNA-damage-inducible alpha); TEGT (Bax inhibitor 1); PIK3CA (phosphoinositide-3-kinase, catalytic, alpha polypeptide); IFNGR2 (interferon gamma receptor 2); JAK2 (Janus Kinase 2); FAS (Fas, TNF receptor superfamily, member 6); TANK (TRAF family member-associated NFKB activator); TTRAP (TRAF and TNF receptor-associated protein); and ANXA5 (annexin A5).

Carvedilol attenuates the progression of alcohol fatty liver disease in rats

BACKGROUND

Hepatosteatosis is an essential step in liver disease progression. However, the mechanisms that mediate the progression of hepatosteatosis and the optimal inhibitor of them remain largely unclear. The sympathetic nervous system (SNS) is responsible for the lipid metabolism and the accumulation of collagen that occurs in an injured liver. Medicines that inhibit this pathway may be a relevant treatment for the hepatosteatosis, and then reduce the liver injury that progresses through the stage of steatosis to fibrosis.

METHODS

Using an ethanol-liquid-diet-fed rat model of alcohol fatty liver disease (AFLD), we studied the effects of carvedilol, which can block the SNS completely via β1, β2, and α1 adrenergic receptors, on the sympathetic tone, hepatosteatosis, and fibrosis based on histological, immunohistochemical, Western blot, and reverse transcriptase polymerase chain reaction analyses.

RESULTS

Carvedilol inhibited the ethanol-induced whole-body and hepatic sympathetic activities based on the serum 3-methoxy-4-hydroxyphenylglycol level and hepatic tyrosine hydroxylase expression. Carvedilol attenuated the hepatosteatosis, as evidenced by reduced hepatic triglyceride level and the accumulation of fatty droplets within hepatocytes, down-regulated fatty acid synthase and sterol regulatory element binding protein-1, and up-regulated peroxisome proliferator-activated receptor-α. No fibrosis signs were shown in our rat model. Carvedilol inhibited ethanol-induced the thickening of zone 3 vessel walls, reduced the activation of hepatic stellate cells (HSCs), and decreased the induction of collagen, transforming growth factor β1, and tissue inhibitor of metalloproteinases-1. Tumor necrosis factor α (TNF-α) was expressed on the activated HSCs and inhibited by carvedilol based on the immunohistochemical double staining analysis.

CONCLUSIONS

Ethanol metabolism-induced lipogenesis may trigger the SNS-activated HSCs feedback loop, and then induct the activated HSCs and the activated HSCs-derived TNF-α, the mediator of lipogenesis, overproduction. Carvedilol may block this feedback loop via antisympathetic activity and demonstrate its preventive role on the development of hepatosteatosis in rat with AFLD.

Harmful lifestyles on orthopedic implantation surgery: a descriptive review on alcohol and tobacco use

Alcohol abuse and smoking habits have adverse effects on bone health and are a risk factor for osteoporosis, fractures and impaired fracture repair. Osteointegration processes around implanted biomaterials involve a coordinated cascade of complex events that are very similar to those occurring during fracture repair and require a suitable microenvironment and the coordinated action of cells and signal molecules. Therefore, diseases and harmful lifestyles that impair the normal bone healing process can reduce the success of implant surgery and may negatively influence the osteointegration of prostheses and implant devices for fracture fixation such as screws, nails and plates. Understanding the effects of harmful lifestyles on bone implant osteointegration is important for successful implant therapy, orthopedic reconstructive surgery and tissue-engineered-based therapies. However, the mechanisms by which smoking and alcoholism affect bone metabolism, bone mass and the balance of bone resorption and formation, also in the presence of an orthopedic implant, are not completely understood and remain inadequately elucidated. This review aims to analyze in vitro and in vivo studies regarding orthopedic implant integration in the presence of tobacco smoking and alcohol consumption with a focus on pathophysiology and local or systemic mechanisms of action on bone.

Pathogenesis of alcohol-induced liver disease: classical concepts and recent advances

Alcoholic liver disease (ALD) is a primary consequence of heavy and prolonged drinking. ALD contributes to the bulk of liver disease burden worldwide. Progression of ALD is a multifactorial and multistep process that includes many genetic and environmental risk factors. The molecular pathogenesis of ALD involves alcohol metabolism and secondary mechanisms such as oxidative stress, endotoxin, cytokines and immune regulators. The histopathological manifestation of ALD occurs as an outcome of complex but controlled interactions between hepatic cell types. Hepatic stellate cells (HSCs) are the key drivers of fibrogenesis, but transformation of hepatocytes to myofibroblastoids also implicate parenchymal cells as playing an active role in hepatic fibrogenesis. Recent discoveries indicate that lipogenesis during the early stages of ALD is a risk for advancement to cirrhosis. Other recently identified novel molecules and physiological/cell signaling pathways include fibrinolysis, osteopontin, transforming growth factor-β-SMAD and hedgehog signaling, and involvement of novel cytokines in hepatic fibrogenesis. The observation that ALD and non-alcoholic steatohepatitis share common pathways and genetic polymorphisms suggests operation of parallel pathogenic mechanisms. Future research involving genomics, epigenomics, deep sequencing and non-coding regulatory elements holds promise to identify novel diagnostic and therapeutic targets for ALD. There is also a need for adequate animal models to study pathogenic mechanisms at the molecular level and targeted therapy.

Ethanol and acetaldehyde disturb TNF-alpha and IL-6 production in cultured astrocytes

Ethanol disturbs astroglial growth and differentiation and causes functional alterations. Furthermore, many signalling molecules produced by astrocytes contribute to these processes. The aim of the present study was to investigate the influence of ethanol and its primary metabolite, acetaldehyde, on TNF-alpha and IL-6 production in a rat cortical astrocyte primary culture. We are the first to report that both ethanol and acetaldehyde can modulate TNF-alpha and IL-6 secretion from cultured astrocytes. Long-term exposure (7 days) to ethanol and acetaldehyde was more toxic than an acute (24 hours) exposure. However, both compounds showed a biphasic, hormestic effect on the IL-6 secretion after the acute as well as the long-term exposure, and the maximum stimulation was reached for 50-mM ethanol and 1-mM acetaldehyde after 7-day exposure. In contrast, both compounds reduced the TNF-alpha secretion, where the effect was concentration-dependent. The catalase inhibitor 2-amino-1,2,4 triazole significantly reduced the ethanol toxicity in the cultured astrocytes after the acute as well as the long-term exposure. In conclusion, both ethanol and acetaldehyde affect the production of IL-6 and TNF-alpha in cultured astrocytes. The effect depends on the concentration of the compounds and the duration of the exposure. Acetaldehyde is a more potent toxin than ethanol, and ethanol's toxicity in the brain is at least partially due to its primary metabolite, acetaldehyde.