Alcohol and the liver

Hepatic artery disorders associated with alcoholism

OBJECTIVE

We aimed to characterize the relationship between severe chronic alcoholism and hepatic arterial wall disorders in humans.

METHODS

We obtained hepatic arteries from 165 patients undergoing liver transplantation who were placed into two etiological groups: an Alcoholism group and a Non-alcoholism group. We compared the age, sex, lipid profile, and histologic characteristics of the hepatic arteries (normal, reduction in luminal diameter of ≤10%, or atherosclerosis) of the participants in the two groups using multifactor analyses.

RESULTS

The Alcoholism group comprised 58 men and 40 women and the Non-alcoholism group comprised 63 men and 4 women. The mean ages of the groups were 52.5 ± 9.6 years and 44.2 ± 13.8 years, respectively. There were no circulating lipid abnormalities in any of the participants. In women, arterial disorders were found at a younger age than in men. Hepatic arterial disorders were more frequent in the non-alcoholic participants, and women with alcoholism showed less arterial narrowing.

CONCLUSION

The heavy consumption of alcoholic beverages is associated with a lower incidence of atherosclerosis of the hepatic artery in humans.

Development of Ectopic Livers by Hepatocyte Transplantation Into Swine Lymph Nodes

Orthotopic liver transplantation continues to be the only effective therapy for patients with end-stage liver disease. Unfortunately, many of these patients are not considered transplant candidates, lacking effective therapeutic options that would address both the irreversible progression of their hepatic failure and the control of their portal hypertension. In this prospective study, a swine model was exploited to induce subacute liver failure. Autologous hepatocytes, isolated from the left hepatic lobe, were transplanted into the mesenteric lymph nodes (LNs) by direct cell injection. At 30-60 days after transplantation, hepatocyte engraftment in LNs was successfully identified in all transplanted animals with the degree of ectopic liver mass detected being proportional to the induced native liver injury. These ectopic livers developed within the LNs showed remarkable histologic features of swine hepatic lobules, including the formation of sinusoids and bile ducts. On the basis of our previous tyrosinemic mouse model and the present pig models of induced subacute liver failure, the generation of auxiliary liver tissue using the LNs as hepatocyte engraftment sites represents a potential therapeutic approach to supplement declining hepatic function in the treatment of liver disease.

Effect of ethanol on lipid metabolism

Hepatic lipid metabolism is a series of complex processes that control influx and efflux of not only hepatic lipid pools, but also organismal pools. Lipid homeostasis is usually tightly controlled by expression, substrate supply, oxidation and secretion that keep hepatic lipid pools relatively constant. However, perturbations of any of these processes can lead to lipid accumulation in the liver. Although it is thought that these responses are hepatic arms of the 'thrifty genome', they are maladaptive in the context of chronic fatty liver diseases. Ethanol is likely unique among toxins, in that it perturbs almost all aspects of hepatic lipid metabolism. This complex response is due in part to the large metabolic demand placed on the organ by alcohol metabolism, but also appears to involve more nuanced changes in expression and substrate supply. The net effect is that steatosis is a rapid response to alcohol abuse. Although transient steatosis is largely an inert pathology, the chronicity of alcohol-related liver disease seems to require steatosis. Better and more specific understanding of the mechanisms by which alcohol causes steatosis may therefore translate into targeted therapies to treat alcohol-related liver disease and/or prevent its progression.

Critical Roles of Kupffer Cells in the Pathogenesis of Alcoholic Liver Disease: From Basic Science to Clinical Trials

Alcoholic liver disease (ALD) encompasses a spectrum of liver injury ranging from steatosis to steatohepatitis, fibrosis, and finally cirrhosis. Accumulating evidences have demonstrated that Kupffer cells (KCs) play critical roles in the pathogenesis of both chronic and acute ALD. It has become clear that alcohol exposure can result in increased hepatic translocation of gut-sourced endotoxin/lipopolysaccharide, which is a strong M1 polarization inducer of KCs. The activated KCs then produce a large amount of reactive oxygen species (ROS), pro-inflammatory cytokines, and chemokines, which finally lead to liver injury. The critical roles of KCs and related inflammatory cascade in the pathogenesis of ALD make it a promising target in pharmaceutical drug developments for ALD treatment. Several drugs (such as rifaximin, pentoxifylline, and infliximab) have been evaluated or are under evaluation for ALD treatment in randomized clinical trials. Furthermore, screening pharmacological regulators for KCs toward M2 polarization may provide additional therapeutic agents. The combination of these potentially therapeutic drugs with hepatoprotective agents (such as zinc, melatonin, and silymarin) may bring encouraging results.

Liver disease in patients undergoing head and neck surgery: Incidence and risk for postoperative complications

OBJECTIVES/HYPOTHESIS

Head and neck cancer patients have multiple risk factors for liver disease. However, little is known about the incidence of liver disease or the safety of surgery in these patients.

STUDY DESIGN

We conducted a retrospective cohort study using the American College of Surgeons National Surgical Quality Improvement Program from 2005 to 2013.

METHODS

We identified patients undergoing head and neck surgery and excluded them if preoperative laboratory data were missing. Patients were classified as having liver disease if their preoperative aspartate aminotransferase-to-platelet ratio index was ≥ 0.7, and as having advanced liver disease if their Model for End-Stage Liver Disease-Sodium score was ≥ 10. We compared the rate of postoperative complications using multivariable logistic regression.

RESULTS

Among 19,138 eligible patients, the incidence of any degree of liver disease was 6.8% for aerodigestive tract surgery and 3.3% for controls. The 30-day mortality rate after major head and neck surgery, which included composite resection; free tissue transfer; and total laryngectomy with advanced, mild, and no liver disease, was 14.6%, 3.0%, and 0.9%, respectively (P < 0.001). For nonmajor surgery, the mortality rate was 3.0%, 0.3%, and 0.3%, respectively (P < 0.001). On multivariable analysis, patients with advanced liver disease experienced a six-fold higher rate of 30-day mortality (odds ratio 6.1; 95% confidence interval, 2.9-12.8).

CONCLUSION

There is a high risk to detect liver disease in patients undergoing head and neck surgery of the aerodigestive tract. Those with advanced liver disease are at high risk for perioperative mortality, and this risk should be judiciously considered in medical/surgical decision making and postoperative care.

LEVEL OF EVIDENCE

2c. Laryngoscope, 127:102-109, 2017.

Binge drinking: Burden of liver disease and beyond

The consumption of alcoholic beverages is harmful to human health. In recent years, consumption patterns of alcoholic beverages have changed in our society, and binge drinking has generalized. It is considered to be a socio-sanitary problem with few known consequences in terms of individual and third-party social impacts (in the form of violence or traffic accidents) and its organic impact (affects the liver and other organs and systems, such as the nervous and cardiovascular systems) and represents an important financial burden due to its increasing economic impact. This review provides a global approach to binge drinking and emphasizes its epidemiological character, the effect of this type of consumption and the possible management of a problem with an increasing tendency in our society.

Dietary modulators of statin efficacy in cardiovascular disease and cognition

Cardiovascular disease remains the leading cause of morbidity and mortality in the United States and other developed countries, and is fast growing in developing countries, particularly as life expectancy in all parts of the world increases. Current recommendations for the prevention of cardiovascular disease issued jointly from the American Academy of Cardiology and American Heart Association emphasize that lifestyle modification should be incorporated into any treatment plan, including those on statin drugs. However, there is a dearth of data on the interaction between diet and statins with respect to additive, complementary or antagonistic effects. This review collates the available data on the interaction of statins and dietary patterns, cognition, genetics and individual nutrients, including vitamin D, niacin, omega-3 fatty acids, fiber, phytochemicals (polyphenols and stanols) and alcohol. Of note, although the available data is summarized, the scope is limited, conflicting and disparate. In some cases it is likely there is unrecognized synergism. Virtually no data are available describing the interactions of statins with dietary components or dietary pattern in subgroups of the population, particularly those who may benefit most were positive effects identified. Hence, it is virtually impossible to draw any firm conclusions at this time. Nevertheless, this area is important because were the effects of statins and diet additive or synergistic harnessing the effect could potentially lead to the use of a lower intensity statin or dose.

Acetaminophen intoxication is associated with decreased serum paraoxonase and arylesterase activities and increased lipid hydroperoxide levels

BACKGROUND

Acetaminophen is at present one of the most commonly used analgesics and antipyretics. Recent evidence has suggested that oxidative stress is involved in the mechanism of acetaminophen intoxication. Paraoxonase-1 (PON1) plays an important role as an endogenous free-radical scavenging molecule. The aim of this study was to evaluate the influence of serum PON1 activity and oxidative stress in patients with acetaminophen intoxication.

METHODS

A total of 20 patients with acetaminophen intoxication and 25 healthy controls were enrolled. Serum total antioxidant capacity (TAC), lipid hydroperoxide (LOOH) levels, and paraoxonase and arylesterase activities were measured spectrophotometrically.

RESULTS

The serum TAC levels and the paraoxonase and arylesterase activities were significantly lower in patients with acetaminophen intoxication compared with controls (all, p < 0.001), while the serum LOOH levels were significantly higher (p < 0.001).

CONCLUSIONS

Our results suggest that decreased PON1 activity seems to be associated with increased oxidative stress in patients with acetaminophen intoxication. Measuring serum PON1 activity may be useful in assessing the development of toxicity risk in acetaminophen toxicity. It would be useful to recommend vitamins with antioxidant effects such as vitamins C and E along with medical treatments.

Binge ethanol and liver: new molecular developments

Binge consumption of alcohol is an alarming global health problem. Binge (acute) ethanol (EtOH) is implicated in the pathophysiology of alcoholic liver disease (ALD). New studies from experimental animals and from humans indicate that binge EtOH has profound effects on immunological, signaling, and epigenetic parameters of the liver. This is in addition to the known metabolic effects of acute EtOH. Binge EtOH alters the levels of several cellular components and dramatically amplifies liver injury in chronically EtOH exposed liver. These studies highlight the importance of molecular investigations into binge effects of EtOH for a better understanding of ALD and also to develop therapeutic strategies to control it. This review summarizes these recent developments.

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.

Alcohol research: past, present, and future

Created forty years ago, the National Institute on Alcohol Abuse and Alcoholism (NIAAA) has played a major role in the great strides made in the understanding, treatment, prevention, and public acceptance of alcohol-use disorders. Throughout most of U.S. history "habitual drunkenness" was viewed as a problem of moral degeneracy or character flaw inherent in the individual. However, the wealth of scientific evidence amassed throughout NIAAA's history has established alcoholism as a medical condition, that is, as a disease for which affected individuals should feel no shame or be treated with disdain. We look at the developments in alcohol epidemiology, typology, etiology, prevention, and treatment research over the past 40 years. We also discuss how NIAAA addresses alcohol disorders from a life-course framework, affecting all stages of the lifespan, from fetus through child, adolescent, and young adult, to midlife/senior adult, with each stage involving different risks, consequences, prevention efforts, and treatment strategies.

Decreased paraoxonase-1 activity is associated with alterations of high-density lipoprotein particles in chronic liver impairment

Background

Paraoxonase-1 (PON1), a lactonase synthesized by the liver, circulates in blood bound to high-density lipoproteins (HDL). This enzyme is thought to degrade oxidized phospholipids and play an important role in the organism's antioxidant and anti-inflammatory system. Chronic liver diseases are characterized by decreased serum PON1 activity. The aim of the present study was to investigate the compositional changes in HDL that could influence PON1 activity in liver impairment.

Methods

The study was performed in samples from five patients with advanced liver cirrhosis and with preserved renal function, chosen on the basis of having low serum PON1 activity and high serum PON1 concentration. As a control group, we accessed five healthy volunteers from among our hospital staff. Lipid and protein compositional analysis of lipoprotein particles were done by high-performance liquid chromatography, gel electrophoresis, and Western-Blot.

Results

HDL particles from cirrhotic patients had an increased phospholipid content that was inversely correlated to PON1 activity. The HDL particles contained high levels of PON1 that corresponded, in part, to an immunoreactive protein of high molecular weight (55 kDa) not present in control subjects. This protein was identified as glycosylated PON1 and was also present in biopsies from patients with steatosis and from rats with CCl₄-induced hepatic impairment. These changes were associated with an increased plasma concentration of markers of oxidative stress, inflammation and fibrogenesis.

Conclusion

Abnormalities in the composition of lipids and proteins of HDL particles, including PON1 glycosylation, are associated with the decrease in serum PON1 activity in patients with liver disease. These alterations may adversely affect the protective role of HDL against oxidative stress and inflammation in these patients.

Frequent expression of Niban in head and neck squamous cell carcinoma and squamous dysplasia

BACKGROUND

Niban was initially identified in the Eker rat, a model of renal carcinogenesis. We examined Niban expression in head and neck squamous cell carcinoma (HNSCC) and head and neck dysplastic lesions.

METHODS

Using a polyclonal rabbit anti-human Niban antibody, 43 cases of HNSCC and 30 cases of head and neck squamous dysplasia were immuonohistochemically stained for Niban. Ancillary genetic studies were also performed.

RESULTS

Forty-two of 43 HNSCCs (97.6%) and 20 of 30 (66.6%) dysplastic lesions were positively stained for Niban. The staining was generally less intense in cases of dysplasia than HNSCC. Three of 8 normal mucosal samples from drinker/smokers also showed weak Niban expression. Normal head and neck squamous epithelium from nondrinker/nonsmokers did not stained for Niban. Reverse transcription polymerase chain reaction results matched the immuonohistochemical results.

CONCLUSION

The expression of Niban frequently begins in the early stages of head and neck squamous carcinoma and remains upregulated throughout the carcinogenic process. Niban may be a good molecular marker of HNSCC.

Chronic ethanol consumption results in atypical liver injury in copper/zinc superoxide dismutase deficient mice

BACKGROUND

Ethanol metabolism increases production of reactive oxygen species, including superoxide (O2(.-)) in the liver, resulting in significant oxidative stress, which causes cellular damage. Superoxide dismutase (SOD) is an antioxidant enzyme that converts superoxide to less toxic intermediates, preventing accumulation. Because the absence of SOD would confer less resistance to oxidative stress, we determined whether damage to hepatic proteolytic systems was greater in SOD(-/-) than in SOD(+/+) mice after chronic ethanol feeding.

METHODS

Female wild-type (SOD(+/+)) and Cu/Zn-SOD knockout (SOD(-/-)) mice were pair-fed ethanol and control liquid diets for 24 days, after which liver injury was assessed.

RESULTS

Ethanol-fed SOD(-/-) mice had 4-fold higher blood ethanol, 2.8-fold higher alanine aminotransferase levels, 20% higher liver weight, a 1.4-fold rise in hepatic protein levels, and 35 to 70% higher levels of lipid peroxides than corresponding wild-type mice. While wild-type mice exhibited fatty liver after ethanol administration, SOD(-/-) mice showed no evidence of ethanol-induced steatosis, although triglyceride levels were elevated in both groups of knockout mice. Ethanol administration caused no significant change in proteasome activity, but caused lysosomal leakage in livers of SOD(-/-) mice but not in wild-type mice. Alcohol dehydrogenase activity was reduced by 50 to 60% in ethanol-fed SOD(-/-) mice compared with all other groups. Additionally, while ethanol administration induced cytochrome P450 2E1 (CYP2E1) activity in wild-type mice, it caused no such induction in SOD(-/-) mice. Unexpectedly, ethanol feeding significantly elevated total and mitochondrial levels of glutathione in SOD knockout mice compared with wild-type mice.

CONCLUSION

Ethanol-fed SOD(-/-) mice exhibited lower alcohol dehydrogenase activity and lack of CYP2E1 inducibility, thereby causing decreased ethanol metabolism compared with wild-type mice. These and other atypical responses to ethanol, including the absence of ethanol-induced steatosis and enhanced glutathione levels, appear to be linked to enhanced oxidative stress due to lack of antioxidant enzyme capacity.

Pancreas and liver injury are associated in individuals with increased alcohol consumption

BACKGROUND & AIMS

Although chronic pancreatitis and liver cirrhosis are common sequelae of excess alcohol consumption, the 2 conditions are rarely associated. We studied the prevalence of simultaneous liver cirrhosis and chronic pancreatitis in alcoholics.

METHODS

Postmortem autopsy data from 620 individuals with a history of excess alcohol consumption and 100 nonalcoholics (controls) were analyzed. The individuals were classified into groups based on macroscopic observations of pancreas (no injury, acute pancreatitis, fibrosis, and chronic pancreatitis) and liver (no injury, moderate steatosis, severe steatosis, and cirrhosis). The same classification system was used for histological data, which was used to confirm and correlate macroscopic results.

RESULTS

Out of the 183 patients with liver cirrhosis, 33 (18%) had chronic pancreatitis and 93 (51%) had pancreatic fibrosis. Out of the 230 patients with severe steatosis, 37 (16%) had chronic pancreatitis and 97 (42%) were found to have a pancreatic fibrosis. Thirty-three (39%) with chronic pancreatitis also showed liver cirrhosis and 37 (44%) showed severe steatosis. Thirty-eight percent of the patients with a pancreatic fibrosis were found also to have liver cirrhosis and in another 40% severe steatosis. Thirty-five patients showed neither hepatic or pancreatic injury. We found no chronic pancreatitis or liver cirrhosis in the control group (n = 100).

CONCLUSIONS

Contrary to common belief there is a close association between pancreatic and hepatic injury in patients with increased alcohol consumption, and the degree of organ damage between the 2 organs correlate.

Non-invasive assessment and quantification of liver steatosis by ultrasound, computed tomography and magnetic resonance

Hepatic steatosis is the most prevalent liver disorder in the developed world. It is closely associated with features of metabolic syndrome, especially insulin resistance and obesity. The two most common conditions associated with fatty liver are alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). Liver biopsy is considered the gold standard for the assessment of liver fat, but there is a need for less invasive diagnostic techniques. New imaging modalities are emerging, which could provide more detailed information about hepatic tissue or even replace biopsy. In the present review, available imaging modalities (ultrasound, computed tomography, magnetic resonance imaging and proton magnetic resonance spectroscopy) are presented which are employed to detect or even quantify the fat content of the liver. The advantages and disadvantages of the above-mentioned imaging modalities are discussed. Although none of these techniques is able to differentiate between microvesicular and macrovesicular steatosis and to reveal all features visible using histology, the proposed diagnostic modalities offer a wide range of additional information such as anatomical and morphological information non-invasively. In particular, magnetic resonance imaging and proton magnetic resonance spectroscopy are able to quantify the hepatic fat content hence avoiding exposure to radiation. Except for proton magnetic resonance spectroscopy, all modalities offer additional information about regional fat distribution within the liver. MR elastography, which can estimate the amount of fibrosis, also appears promising in the differentiation between simple steatosis and steatohepatitis.

Do common genetic variants in endotoxin signaling pathway contribute to predisposition to alcoholic liver cirrhosis?

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta), produced by endotoxin-activated Kupffer cells, play a key role in the pathogenesis of alcoholic liver cirrhosis (ALC). Alleles TNFA -238A, IL1B -31T and variant IL1RN*2 of repeat polymorphism in the gene encoding the IL-1 receptor antagonist increase production of TNF-alpha and IL-1beta, respectively. Alleles CD14 -159T, TLR4 c.896G and TLR4 c.1196T modify activation of Kupffer cells by endotoxin. We confirmed the published associations between these common variants and genetic predisposition to ALC by means of a large case-control association study conducted on two Central European populations.

METHODS

The study population comprised a Czech sample of 198 ALC patients and 370 controls (MONICA project), and a German sample of 173 ALC patients and 331 controls (KORA-Augsburg), and 109 heavy drinkers without liver disease.

RESULTS

Single locus analysis revealed no significant difference between patients and controls in all tested loci. Diplotype [IL1RN 2/ 2; IL1B -31T+] was associated with increased risk of ALC in the pilot study, but not in the validation samples.

CONCLUSIONS

Although cytokine mediated immune reactions play a role in the pathogenesis of ALC, hereditary susceptibility caused by variants in the corresponding genes is low in Central European populations.

The positive and negative health effects of alcohol- and the public health implications

In this paper, the negative and the positive effects of alcohol on health are reviewed. It is first of all established facts that a high alcohol intake implies an increased risk of a large number of health outcomes, such as dementia, breast cancer, colorectal cancer, cirrhosis, upper digestive tract cancer and alcohol dependency. Second, it is justified that alcohol has beneficial effects for some individuals, especially with regard to prevention of thrombosis of the heart. The public health relevance of these results is considered. The sensible drinking limits, used in both the UK and Denmark, of a maximum of 21 drinks per week for men and 14 drinks per week for women seem valid. A broader public health message of the beneficial effects of alcohol does not seem to be of interest in Western societies, where only a very small fraction of the population are non drinkers and may have very good reasons therefore.

Protective effect of puerarin on rats with alcoholic hepatitis

AIM: To investigate mechanism of puerarin on alcoholic hepatitis in rats.

METHODS: Twenty-one Wistar rats were divided into three groups randomly, with intragastric administration of the control group by corn oil + 500 g/L glucose 20 mL/(kg•d); intragastric administration of the model group by 400 mL/L alcohol 8 g/(kg•d)+ corn oil; peritoneal injection of the puerarin group by puerarin 5 mg/(kg•d); After thirty days. Serum and liver tissue samples were prepared, and the levels of alanine transaminase (ALT), aspartate transaminase (AST), and γ-glutamyltranspeptidase (GST) were determined by chromatometry, serum PGE2, TNF-α and IL-6 by radioimmunity method, and COX-2 expression on the hepatic tissue by Western blot. Pathological changes on hepatic tissue was determined by light microscopy.

RESULTS: The serum ALT, AST and GST was significantly higher in model group than in control group (107.5 ± 6.81 vs 33.20 ± 10.55, 138.29 ± 9.72 vs 47.86 ± 14.3, 3.57 ± 0.53 vs 1.43 ± 0.43, all P < 0.01). The serum ALT and AST was significantly lower in puerarin group than in model group (52.33 ± 13.19, 63.33 ± 7.03, P < 0.01). The serum GST level was lower, but not significantly. The levels of serum PGE2, TNF-α and IL-6 were significantly higher in model group than in control group (274.13 ± 26.15 vs 193.84 ± 23.97, 1.85 ± 0.11 vs 0.90±0.18, 68.07 ± 12.64 vs 40.50 ± 5.09, all P < 0.01), and the levels of the serum PGE2, TNF-α and IL-6 were significantly lower in puerarin group than in model group (227.05 ± 21.55, 1.35 ± 0.19, 53.16 ± 5.62, all P < 0.01). Expression of COX-2, was weak, but had high expression in model group(P < 0.01). The expression of COX-2 in puerarin group was down regulated, compared with model group (P < 0.01).

CONCLUSION: Puerarin has effects on hepatic injury in alcoholic hepatitis.

Evidence that chronic alcohol exposure promotes intestinal oxidative stress, intestinal hyperpermeability and endotoxemia prior to development of alcoholic steatohepatitis in rats

BACKGROUND/AIMS

Not all alcoholics develop liver disease (ALD). Thus, excessive ethanol consumption is necessary, but not sufficient, to induce alcoholic steatohepatitis (ASH) and ALD. Since endotoxemia is present in patients with ALD, it has been proposed that gut-derived, circulating endotoxin is the necessary co-factor for ASH. But, it is not known whether endotoxemia is the consequence or the trigger for ALD. Accordingly, the aim of the current study was to determine whether endotoxemia occurs prior to development of ASH and whether gut leakiness is the primary cause of the endotoxemia in an animal model of ASH.

METHODS

Time courses for development of gut hyperpermeability, nitric oxide production, oxidative injury to the gut, endotoxemia, and liver injury were assessed in rats during 10 weeks of daily alcohol gavage.

RESULTS

Liver fat and serum transaminase increased after 2 weeks, but evidence of liver cell injury and inflammation (ASH) occurred after 8 weeks. Gut leakiness, intestinal oxidative injury, and endotoxemia occurred in weeks 2-4 and progressed thereafter.

CONCLUSIONS

That alcohol-induced gut leakiness and endotoxemia preceded steatohepatitis indicates they are not the consequence of ALD. Our data support the hypothesis that gut leakiness resulting in endotoxemia is a key co-factor (trigger) for ASH.

Cross-talk between pulmonary injury, oxidant stress, and gap junctional communication

Gap junction channels interconnect several different types of cells in the lung, ranging from the alveolar epithelium to the pulmonary vasculature, each of which expresses a unique subset of gap junction proteins (connexins). Major lung functions regulated by gap junctional communication include coordination of ciliary beat frequency and inflammation. Gap junctions help enable the alveolus to regulate surfactant secretion as an integrated system, in which type I cells act as mechanical sensors that transmit calcium transients to type II cells. Thus, disruption of epithelial gap junctional communication, particularly during acute lung injury, can interfere with these processes and increase the severity of injury. Consistent with this, connexin expression is altered during lung injury, and connexin-deficiency has a negative impact on the injury response and lung-growth control. It has recently been shown that alcohol abuse is a significant risk factor associated with acute respiratory distress syndrome. Oxidant stress and hormone-signaling cascades in the lung induced by prolonged alcohol ingestion are discussed, as well as the effects of these pathways on connexin expression and function.

Novel Objective Biomarkers of Alcohol Use: Potential Diagnostic and Treatment Management Tools in Dual Diagnosis Care

Alcohol use disorders are highly prevalent conditions that generate a large fraction of the total public health burden. These disorders are concentrated in mentally ill populations, in which reliability of self-reporting of alcohol consumption may be especially compromised. The application of objective biomarkers for alcohol use may therefore play an important role in these patients. This article provides a description and comparative overview of traditional versus novel biomarkers of alcohol consumption. Greater professional familiarity with and use of novel biomarkers as diagnostic and treatment management tools may enhance clinical standards and research on alcohol use in patients with a dual diagnosis.

Risk factors for alcohol-related liver injury in the island population of China: A population-based case-control study

AIM: To investigate the association of alcohol dose, duration of drinking and obesity with abnormal alcohol-related liver injury indicators, the prevalence of alcohol-related liver injury in the island population of China.

METHODS: Randomized multistage stratified cluster sampling from the island population of China was used in the population-based case-control study. Then interview, physical examination, laboratory assessments and ultrasonography were done.

RESULTS: Daily alcohol intake ≥ 20 g, duration of drinking ≥ 5 years and obesity were closely related to alcohol-related liver injury (P < 0.05). The odds-ratio (OR) (95% CI) was 1.965 (1.122-3.442), 3.412 (1.789-6.507) and 1.887 (1.261-2.824), respectively. The prevalence rate of alcohol-related liver injury in ≥ 20 g daily alcohol intake group and < 20 g daily alcohol intake group was 37.14% and 12.06%, respectively. The prevalence rate of alcohol-related liver injury in ≥ 5 years drinking group and < 5 years drinking group was 34.44% and 8.53%, respectively. No significant dose-response relation was found between daily alcohol intake and abnormal alcohol-related liver injury indicators as well as between duration of drinking and abnormal alcohol-related liver injury indicators. There was no significant difference in the prevalence of alcohol-related liver injury between beer drinking group and yellow rice wine drinking group, hard liquor drinking group, multiple drinking group.

CONCLUSION: The risk threshold of daily alcohol intake is 20 g and duration of drinking inducing alcohol-related liver injury 5 years in the island population of China. Liver injury induced by obesity should be concerned.

Mitochondrial dysfunction and oxidative stress in the pathogenesis of alcohol- and obesity-induced fatty liver diseases

Fatty liver disease associated with chronic alcohol consumption or obesity/type 2 diabetes has emerged as a serious public health problem. Steatosis, accumulation of triglyceride in hepatocytes, is now recognized as a critical "first-hit" in the pathogenesis of liver disease. It is proposed that steatosis "primes" the liver to progress to more severe liver pathologies when individuals are exposed to subsequent metabolic and/or environmental stressors or "second-hits." Genetic risk factors can also influence the susceptibility to and severity of fatty liver disease. Furthermore, oxidative stress, disrupted nitric oxide (NO) signaling, and mitochondrial dysfunction are proposed to be key molecular events that accelerate or worsen steatosis and initiate progression to steatohepatitis and fibrosis. This review article will discuss the following topics regarding the pathobiology and molecular mechanisms responsible for fatty liver disease: (1) the "two-hit" or "multi-hit" hypothesis, (2) the role of mitochondrial bioenergetic defects and oxidant stress, (3) the interplay between NO and mitochondria in fatty liver disease, (4) genetic risk factors and oxidative stress-responsive genes, and (5) the feasibility of antioxidants for treatment.

Hepatic NKT cells: friend or foe?

The innate immune system represents a critical first line of host response to infectious, injurious and inflammatory insults. NKT cells (natural killer T-cells) are an important, but relatively poorly understood, component of the innate immune response. Moreover, NKT cells are enriched within the liver, suggesting that within the hepatic compartment NKT cells probably fulfil important roles in the modulation of the immune response to infection or injury. NKT cells are characterized by their rapid activation and secretion of large amounts of numerous types of cytokines, including those within the Th1-type, Th2-type and Th17-type groups, which in turn can interact with a multitude of other cell types within the liver. In addition, NKT cells are capable of participating in a wide array of effector functions with regards to other cell types via NKT cell-surface-molecule expression [e.g. FASL (FAS ligand) and CD40L (CD40 ligand)] and the release of mediators (e.g. perforin and granzyme) contained in cellular granules, which in turn can activate or destroy other cells (i.e. immune or parenchymal cells) within the liver. Given the huge scope of potential actions that can be mediated by NKT cells, it has become increasingly apparent that NKT cells may fulfil both beneficial (e.g. clearance of virally infected cells) and harmful (e.g. induction of autoimmunity) roles in the setting of liver disease. This review will outline the possible roles which may be played by NKT cells in the setting of specific liver diseases or conditions, and will discuss the NKT cell in the context of its role as either a ‘friend’ or a ‘foe’ with respect to the outcome of these liver disorders.

Lipid accumulation in non-adipose tissue and lipotoxicity

Obesity is a well-known risk factor for the development of type 2 diabetes mellitus and cardiovascular disease. Importantly, obesity is not only associated with lipid accumulation in adipose tissue, but also in non-adipose tissues. The latter is also known as ectopic lipid accumulation and may be a possible link between obesity and its comorbidities such as insulin resistance, type 2 diabetes mellitus and cardiovascular disease. In skeletal muscle and liver, lipid accumulation has been associated with the development of insulin resistance, an early hallmark of developing type 2 diabetes mellitus. More specifically, accumulation of intermediates of lipid metabolism, such as diacylglycerol (DAG) and Acyl-CoA have been shown to interfere with insulin signaling in these tissues. Initially, muscular and hepatic insulin resistance can be overcome by an increased insulin production by the pancreas, resulting in hyperinsulinemia. However, during the progression towards overt type 2 diabetes, pancreatic failure occurs resulting in reduced insulin production. Interestingly, also in the pancreas lipid accumulation has been shown to precede dysfunction. Finally, accumulation of fat in the heart has been associated with cardiac dysfunction and heart failure, which may be an explanation for diabetic cardiomyopathy. Taken together, we conclude that evidence for deleterious effects of lipid accumulation in non-adipose tissue (lipotoxicity) is strong. However, while ample human data is available for skeletal muscle and the liver, future research should focus on lipid accumulation in the pancreas and the heart.

Determinants of alcohol use and abuse: Impact of quantity and frequency patterns on liver disease

More than 70% of alcohol is consumed by 10% of the population in the United States. Implicit in this statistic is that tremendous variation in the pattern of drinking (quantity, frequency, and duration) exists among alcohol consumers. Individuals who are binge or chronic drinkers will have different health outcomes than social drinkers. Therefore, knowing the pattern of drinking will shed light on how severely individuals are alcohol-dependent and on the extent of liver damage. Thus, these parameters assume particular relevance for the treatment-providing physician. Genetic factors contribute substantially to differences in alcohol metabolism. Variations in the activities of the alcohol-metabolizing enzymes, cytosolic alcohol dehydrogenase and mitochondrial aldehyde dehydrogenase, in part determine blood alcohol concentration, thereby contributing to the predisposition to becoming alcohol-dependent and to susceptibility to alcohol-induced liver damage. Chronic alcohol consumption induces cytochrome P450 2E1, a microsomal enzyme that metabolizes alcohol at high concentrations and also metabolizes medications such as acetaminophen and protease inhibitors. Alcohol metabolism changes the redox state of the liver, which leads to alterations in hepatic lipid, carbohydrate, protein, lactate, and uric acid metabolism. The quantity and frequency of alcohol consumption severely impact the liver in the presence of comorbid conditions such as infection with hepatitis B or C and/or human immunodeficiency virus, type 2 diabetes, hemochromatosis, or obesity and thus have implications with respect to the extent of injury and response to medications.

CONCLUSION

Knowledge of the relationships between the quantity, frequency, and patterns of drinking and alcoholic liver disease is limited. A better understanding of these relationships will guide hepatologists in managing alcoholic liver disease.