Alcohol-Associated Liver Disease: East Versus West

Alcohol-associated liver disease

Alcohol-associated liver disease (ALD) is a major cause of chronic liver disease worldwide, and comprises a spectrum of several different disorders, including simple steatosis, steatohepatitis, cirrhosis, and superimposed hepatocellular carcinoma. Although tremendous progress has been made in the field of ALD over the last 20 years, the pathogenesis of ALD remains obscure, and there are currently no FDA-approved drugs for the treatment of ALD. In this Review, we discuss new insights into the pathogenesis and therapeutic targets of ALD, utilizing the study of multiomics and other cutting-edge approaches. The potential translation of these studies into clinical practice and therapy is deliberated. We also discuss preclinical models of ALD, interplay of ALD and metabolic dysfunction, alcohol-associated liver cancer, the heterogeneity of ALD, and some potential translational research prospects for ALD.

Hepatocyte-specific mitogen-activated protein kinase phosphatase 1 in sexual dimorphism and susceptibility to alcohol induced liver injury

Background

It is well established that females are more susceptible to the toxic effects of alcohol, although the exact mechanisms are still poorly understood. Previous studies noted that alcohol reduces the expression of mitogen-activated protein kinase phosphatase 1 (MKP1), a negative regulator of mitogen-activated protein kinases (MAPK) in the liver. However, the role of hepatocyte- specific MKP1 in the pathogenesis of alcohol-associated liver disease (ALD) remains uncharacterized. This study aimed to evaluate the role of hepatocyte-specific MKP1 in the susceptibility and sexual dimorphism in alcohol-induced liver injury.

Methods

C57Bl/6 mice were used in an intragastric ethanol feeding model of alcohol-associated steatohepatitis (ASH). Hepatocyte-specific Mkp1-/- knockout and (Mkp1+/+ "f/f" male and female mice were subjected to the NIAAA chronic plus binge model. Primary mouse hepatocytes were used for in vitro studies. Liver RNA sequencing was performed on an Illumina NextSeq 500. Liver injury was evaluated by plasma alanine transaminase (ALT), hepatic ER stress and inflammation markers. Statistical analysis was carried out using ANOVA and the unpaired Student's t-test.

Results

ASH was associated with the severe injury accompanied by increased endoplasmic reticulum (ER) stress and significant downregulation of Dusp1 mRNA expression. In vitro, ethanol treatment resulted in a time-dependent decrease in Dusp1 mRNA and protein expression in primary hepatocytes in both males and females; however, this effect was significantly more pronounced in hepatocytes from females. In vivo, female mice developed more liver injury in a chronic plus binge model which was accompanied by a significant decrease in liver Dusp1 mRNA expression. In comparison, liver Dusp1 was not changed in male mice, while they developed milder injury to alcohol. Mkp1 deletion in hepatocytes led to increased alcohol induced liver injury, ER stress and inflammation in both sexes.

Conclusion

Hepatocyte Mkp1 plays a significant role in alcohol induced liver injury. Alcohol downregulates Mkp1 expression in hepatocytes in a sex dependent manner and could play a role in sexual dimorphism in increased female susceptibility to alcohol.

Healthcare affordability and effects on mortality among adults with liver disease from 2004 to 2018 in the United States

BACKGROUND & AIMS

Liver disease is associated with substantial morbidity and mortality, likely incurring financial distress (i.e. healthcare affordability and accessibility issues), although long-term national-level data are limited.

METHODS

Using the National Health Interview Survey from 2004 to 2018, we categorised adults based on report of liver disease and other chronic conditions linked to mortality data from the National Death Index. We estimated age-adjusted proportions of adults reporting healthcare affordability and accessibility issues. Multivariable logistic regression and Cox regression were used to assess the association of liver disease with financial distress and financial distress with all-cause mortality, respectively.

RESULTS

Among adults with liver disease (n = 19,407) vs. those without liver disease (n = 996,352), those with cancer history (n = 37,225), those with emphysema (n = 7,937), and those with coronary artery disease (n = 21,510), the age-adjusted proportion reporting healthcare affordability issues for medical services was 29.9% (95% CI 29.7-30.1%) vs. 18.1% (95% CI 18.0-18.3%), 26.5% (95% CI 26.3-26.7%), 42.2% (95% CI 42.1-42.4%), and 31.6% (31.5-31.8%), respectively, and for medications: 15.5% (95% CI 15.4-15.6%) vs. 8.2% (95% CI 8.1-8.3%), 14.8% (95% CI 14.7-14.9%), 26.1% (95% CI 26.0-26.2%), and 20.6% (95% CI 20.5-20.7%), respectively. In multivariable analysis, liver disease (vs. without liver disease, vs. cancer history, vs. emphysema, and vs. coronary artery disease) was associated with inability to afford medical services (adjusted odds ratio [aOR] 1.84, 95% CI 1.77-1.92; aOR 1.32, 95% CI 1.25-1.40; aOR 0.91, 95% CI 0.84-0.98; and aOR 1.11, 95% CI 1.04-1.19, respectively) and medications (aOR 1.92, 95% CI 1.82-2.03; aOR 1.24, 95% CI 1.14-1.33; aOR 0.81, 95% CI 0.74-0.90; and aOR 0.94, 95% CI 0.86-1.02, respectively), delays in medical care (aOR 1.77, 95% CI 1.69-1.87; aOR 1.14, 95% CI 1.06-1.22; aOR 0.88, 95% CI 0.79-0.97; and aOR 1.05, 95% CI 0.97-1.14, respectively), and not receiving the needed medical care (aOR 1.86, 95% CI 1.76-1.96; aOR 1.16, 95% CI 1.07-1.26; aOR 0.89, 95% CI 0.80-0.99; aOR 1.06, 95% CI 0.96-1.16, respectively). In multivariable analysis, among adults with liver disease, financial distress (vs. without financial distress) was associated with increased all-cause mortality (aHR 1.24, 95% CI 1.01-1.53).

CONCLUSIONS

Adults with liver disease face greater financial distress than adults without liver disease and adults with cancer history. Financial distress is associated with increased risk of all-cause mortality among adults with liver disease. Interventions to improve healthcare affordability should be prioritised in this population.

IMPACT AND IMPLICATIONS

Adults with liver disease use many medical services, but long-term national studies regarding the financial repercussions and the effects on mortality for such patients are lacking. This study shows that adults with liver disease are more likely to face issues affording medical services and prescription medication, experience delays in medical care, and needing but not obtaining medical care owing to cost, compared with adults without liver disease, adults with cancer history, are equally likely as adults with coronary artery disease, and less likely than adults with emphysema-patients with liver disease who face these issues are at increased risk of death. This study provides the impetus for medical providers and policymakers to prioritise interventions to improve healthcare affordability for adults with liver disease.

Global epidemiology of cirrhosis - aetiology, trends and predictions

Cirrhosis is an important cause of morbidity and mortality in people with chronic liver disease worldwide. In 2019, cirrhosis was associated with 2.4% of global deaths. Owing to the rising prevalence of obesity and increased alcohol consumption on the one hand, and improvements in the management of hepatitis B virus and hepatitis C virus infections on the other, the epidemiology and burden of cirrhosis are changing. In this Review, we highlight global trends in the epidemiology of cirrhosis, discuss the contributions of various aetiologies of liver disease, examine projections for the burden of cirrhosis, and suggest future directions to tackle this condition. Although viral hepatitis remains the leading cause of cirrhosis worldwide, the prevalence of non-alcoholic fatty liver disease (NAFLD) and alcohol-associated cirrhosis are rising in several regions of the world. The global number of deaths from cirrhosis increased between 2012 and 2017, but age-standardized death rates (ASDRs) declined. However, the ASDR for NAFLD-associated cirrhosis increased over this period, whereas ASDRs for other aetiologies of cirrhosis declined. The number of deaths from cirrhosis is projected to increase in the next decade. For these reasons, greater efforts are required to facilitate primary prevention, early detection and treatment of liver disease, and to improve access to care.

Emerging Biomarkers in Alcohol-associated Hepatitis

Alcohol-associated hepatitis (AH) is a clinical syndrome of jaundice, abdominal pain, and anorexia due to prolonged heavy alcohol intake. AH is associated with changes in gene expression, cytokines, immune response, and the gut microbiome. There are limited biomarkers to diagnose and prognosticate in AH, but several non-invasive biomarkers are emerging. In this review, clinical risk-stratifying algorithms, promising AH biomarkers like cytokeratin-18 fragments, genetic polymorphisms, and microRNAs will be reviewed.

Global epidemiology of alcohol-associated cirrhosis and HCC: trends, projections and risk factors

Heavy alcohol consumption is a major cause of morbidity and mortality. Globally, alcohol per-capita consumption rose from 5.5 litres in 2005 to 6.4 litres in 2016 and is projected to increase further to 7.6 litres in 2030. In 2019, an estimated 25% of global cirrhosis deaths were associated with alcohol. The global estimated age-standardized death rate (ASDR) of alcohol-associated cirrhosis was 4.5 per 100,000 population, with the highest and lowest ASDR in Africa and the Western Pacific, respectively. The annual incidence of hepatocellular carcinoma (HCC) among patients with alcohol-associated cirrhosis ranged from 0.9% to 5.6%. Alcohol was associated with approximately one-fifth of global HCC-related deaths in 2019. Between 2012 and 2017, the global estimated ASDR for alcohol-associated cirrhosis declined, but the ASDR for alcohol-associated liver cancer increased. Measures are required to curb heavy alcohol consumption to reduce the burden of alcohol-associated cirrhosis and HCC. Degree of alcohol intake, sex, older age, obesity, type 2 diabetes mellitus, gut microbial dysbiosis and genetic variants are key factors in the development of alcohol-associated cirrhosis and HCC. In this Review, we discuss the global epidemiology, projections and risk factors for alcohol-associated cirrhosis and HCC.

Hepatic Histopathology Among Excessive Drinkers Without Advanced Liver Disease

AIMS

Alcohol-associated liver disease represents a spectrum of histopathological changes from steatosis to advanced fibrosis and cirrhosis. The major goals of this retrospective study were to characterize the histologic features in patients with excessive alcohol use who presented with an abnormal hepatic panel and/or abnormal radiographic imaging and did not meet the clinical diagnosis of alcoholic hepatitis or cirrhosis.

METHODS

We performed a retrospective study to describe hepatic histology of 62 and 83 excessive drinkers with normal and abnormal serum aspartate transaminase, respectively. The types of inflammatory cells in the liver were characterized by immunohistochemistry for CD4, CD8, CD20, CD68 and myeloperoxidase.

RESULTS

Among 62 patients with aspartate aminotransferase (AST) ≤ 50 U/L, 37% had histological evidence of steatosis. Of these, we found evidence of hepatocyte ballooning (21%), lobular inflammation (50%), portal inflammation (52%) and fibrosis (14%). For those with AST > 50 U/L, the presence of hepatic steatosis, lobular inflammation and portal inflammation was observed in 29, 60 and 69% of patients, respectively. Fibrosis was found in 33%, four with bridging fibrosis, and one with cirrhosis. We observed the aggregation of CD68+ macrophages, rather than normally distributed with minimal neutrophilic infiltration. Lobular and portal lymphocytic infiltrations are primarily CD8+ T cells.

CONCLUSION

Abnormal hepatic histopathology occurs in excessive drinkers with normal transaminase activity. Future studies to determine the diagnostic modalities to detect such abnormalities and to better understand its clinical implications and long-term outcome are needed.