Predictive factors for pure steatosis in alcoholic patients

Genetic and Epigenetic Modifiers of Alcoholic Liver Disease

Alcoholic liver disease (ALD), a disorder caused by excessive alcohol consumption is a global health issue. More than two billion people consume alcohol in the world and about 75 million are classified as having alcohol disorders. ALD embraces a wide spectrum of hepatic lesions including steatosis, alcoholic steatohepatitis (ASH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). ALD is a complex disease where environmental, genetic, and epigenetic factors contribute to its pathogenesis and progression. The severity of alcohol-induced liver disease depends on the amount, method of usage and duration of alcohol consumption as well as on age, gender, presence of obesity, and genetic susceptibility. Genome-wide association studies and candidate gene studies have identified genetic modifiers of ALD that can be exploited as non-invasive biomarkers, but which do not completely explain the phenotypic variability. Indeed, ALD development and progression is also modulated by epigenetic factors. The premise of this review is to discuss the role of genetic variants and epigenetic modifications, with particular attention being paid to microRNAs, as pathogenic markers, risk predictors, and therapeutic targets in ALD.

Ethnicity matters: A Systematic Review and Meta-Analysis of the Non-Linear Relationship Between Alcohol Consumption and Prevalence and Incidence of Hepatic Steatosis

BACKGROUND

Fatty liver (hepatic steatosis) is one of the most common diseases globally, with increasing prevalence. The role of alcohol consumption in the development of hepatic steatosis has not been systematically examined.

METHODS

We searched Medline, Embase, and ProQuest Dissertations & Theses Global for original data on the relationship between alcohol consumption and hepatic steatosis measured by non-invasive imagery, excluding studies conducted in participants <18years, or subgroups related to viral and drug-induced liver disease. We identified 18 articles reporting adjusted data (Japan=11, other high-income countries=7). Random-effect categorical meta-analyses (<20g/day pure alcohol consumption vs non-drinkers) and dose-response meta-analyses for the whole range of alcohol consumption were conducted.

RESULTS

In total, 99,370 participants and 25,662 cases of hepatic steatosis were included. In Japan, low alcohol consumption was consistently associated with substantially reduced incidence and prevalence of hepatic steatosis compared to non-drinkers (RR for <20g pure alcohol/day=0.75, 95% CI: 0.71-0.79, I(2)=0%). No overall association was found in other countries (RR=1.05, 95% CI: 0.86-1.30, I(2)=84%). Dose-response analyses in Japan (up to 80g/day) showed an inverse relationship in men and a J-shape in women.

CONCLUSIONS

Alcohol consumption showed a complex association with hepatic steatosis with substantial differences by ethnicity and sex. Low alcohol consumption was beneficial in Japan with good epidemiological evidence, whereas there was no association in other countries. However, heterogeneity was large in countries other than Japan. More and higher quality research in diverse ethnic populations is needed to further clarify this relationship.

Body fat distribution and risk factors for fibrosis in patients with alcoholic liver disease

BACKGROUND

Only a small proportion of alcoholic patients develop advanced liver disease, suggesting that factors other than alcohol intake may influence alcoholic liver disease (ALD) progression. We have shown that body mass index (BMI) is an independent risk factor for fibrosis in alcohol-induced liver disease and that adipose tissue inflammation is correlated with liver lesions in alcoholic patients. The aim of this study was to determine whether visceral adipose tissue, as assessed by abdominal height measurement, affected individual susceptibility to fibrosis in alcoholic patients.

METHODS

We included 127 consecutive alcoholic patients with abnormal liver test findings for whom liver histology data were available. Abdominal height was measured with a Holtain-Kahn abdominal caliper. We carried out univariate comparisons followed by multivariate regression analysis, to investigate the relationship between abdominal height and fibrosis score.

RESULTS

Abdominal height (p < 0.005), waist circumference (p < 0.05), fasting blood glucose concentration (p < 0.05), serum triglyceride concentration (p < 0.05), serum bilirubin (p < 0.005), and BMI (p = 0.05) were higher, whereas high-density lipoprotein (HDL) cholesterol level (p < 0.01) was lower in the 72 patients with significant (F2-F4) fibrosis than in the 55 patients with F0-F1 fibrosis. In multivariate regression analysis, only abdominal height (β = 7.2, p < 0.002) was independently and positively correlated with fibrosis score, which was also negatively correlated with HDL cholesterol level (β = -1.04, p < 0.05).

CONCLUSIONS

We provide the first demonstration that abdominal height may be a predictor of significant fibrosis in patients with ALD. Our findings support a role for visceral fat accumulation, independent of BMI and of metabolic syndrome criteria, in the onset of alcoholic liver damage.

Multicausality in fatty liver disease: Is there a rationale to distinguish between alcoholic and non-alcoholic origin?

Apart from alcohol, there are other factors that may induce complications, which resemble alcohol-related liver disorders. In particular, obesity has been brought into focus as a risk factor for fatty liver disease. The term “non-alcoholic” fatty liver disease is commonly used to distinguish between obesity-related and alcohol-related hepatic steatosis. This review uses the epidemiological perspective to critically assess whether it is necessary and useful to differentiate between alcoholic and “non-alcoholic” fatty liver disease. The MEDLINE database was searched using the PubMed search engine, and a review of reference lists from original research and review articles was conducted. The concept to distinguish between alcoholic and “non-alcoholic” fatty liver disease is mainly based on specific pathomechanisms. This concept has, however, several limitations including the common overlap between alcohol misuse and obesity-related metabolic disorders and the non-consideration of additional causal factors. Both entities share similar histopathological patterns. Studies demonstrating differences in clinical presentation and outcome are often biased by selection. Risk factor reduction is the main principle of prevention and treatment of both disease forms. In conclusion, alcoholic and “non-alcoholic” fatty liver diseases are one and the same disease caused by different risk factors. A shift from artificial categories to a more general approach to fatty liver disease as a multicausal disorder may optimize preventive strategies and help clinicians more effectively treat patients at the individual level.

The osteopontin level in liver, adipose tissue and serum is correlated with fibrosis in patients with alcoholic liver disease

Background

Osteopontin (OPN) plays an important role in the progression of chronic liver diseases. We aimed to quantify the liver, adipose tissue and serum levels of OPN in heavy alcohol drinkers and to compare them with the histological severity of hepatic inflammation and fibrosis.

Methodology/Principal Findings

OPN was evaluated in the serum of a retrospective and prospective group of 109 and 95 heavy alcohol drinkers, respectively, in the liver of 34 patients from the retrospective group, and in the liver and adipose tissue from an additional group of 38 heavy alcohol drinkers. Serum levels of OPN increased slightly with hepatic inflammation and progressively with the severity of hepatic fibrosis. Hepatic OPN expression correlated with hepatic inflammation, fibrosis, TGFβ expression, neutrophils accumulation and with the serum OPN level. Interestingly, adipose tissue OPN expression also correlated with hepatic fibrosis even after 7 days of alcohol abstinence. The elevated serum OPN level was an independent risk factor in estimating significant (F≥2) fibrosis in a model combining alkaline phosphatase, albumin, hemoglobin, OPN and FibroMeter® levels. OPN had an area under the receiving operator curve that estimated significant fibrosis of 0.89 and 0.88 in the retrospective and prospective groups, respectively. OPN, Hyaluronate (AUROC: 0.88), total Cytokeratin 18 (AUROC: 0.83) and FibroMeter® (AUROC: 0.90) estimated significance to the same extent in the retrospective group. Finally, the serum OPN levels also correlated with hepatic fibrosis and estimated significant (F≥2) fibrosis in 86 patients with chronic hepatitis C, which suggested that its elevated level could be a general response to chronic liver injury.

Conclusion/Significance

OPN increased in the liver, adipose tissue and serum with liver fibrosis in alcoholic patients. Further, OPN is a new relevant biomarker for significant liver fibrosis. OPN could thus be an important actor in the pathogenesis of this chronic liver disease.

Harmful effect of adipose tissue on liver lesions in patients with alcoholic liver disease

BACKGROUND & AIMS

Adipose tissue is an important source of cytokines. Excess weight is an independent risk factor for steatosis, acute alcoholic hepatitis (AAH), and cirrhosis in patients with alcoholic liver disease (ALD). In this study, we investigated the role of adipose tissue in human ALD.

PATIENTS AND METHODS

Fifty patients with ALD underwent liver and abdominal subcutaneous adipose tissue biopsies and supplied blood samples for the investigation of cytokine gene expression and secretion, as well as liver histology.

RESULTS

The levels of TNF-alpha and IL-10 in adipose tissue were higher in patients with AAH. IL-10 level in adipose tissue was also correlated with fibrosis score. TNF-alpha gene expression in adipose tissue was correlated with Maddrey score, blood C-reactive protein (CRP) concentration and liver IL-6 concentration. IL-6 production levels in the liver were higher in patients with AAH and correlated with AAH score, liver histological lesions, liver TNF-alpha concentration, Maddrey score, and blood CRP concentration. Plasma concentrations of soluble forms of TNF-receptor were correlated with inflammatory lesions in the liver, Maddrey score and fibrosis score.

CONCLUSION

In patients with ALD, inflammation occurs not only in the liver, but also in the adipose tissue. Adipose tissue inflammation is correlated with the severity of pathological features in the liver. Our findings may account for the harmful interactions between body mass index, AAH, fibrosis, and cirrhosis in alcoholic patients.