Biomarker and Genomic Risk Factors for Liver Function Test Abnormality in Hazardous Drinkers

Active Components of Pueraria lobata through the MAPK/ERK Signaling Pathway Alleviate Iron Overload in Alcoholic Liver Disease

OBJECTIVE

To delve into the primary active ingredients and mechanism of Pueraria lobata for alleviating iron overload in alcoholic liver disease.

METHODS

Pueraria lobata's potential targets and signaling pathways in treating alcohol-induced iron overloads were predicted using network pharmacology analysis. Then, animal experiments were used to validate the predictions of network pharmacology. The impact of puerarin or genistein on alcohol-induced iron accumulation, liver injury, oxidative stress, and apoptosis was assessed using morphological examination, biochemical index test, and immunofluorescence. Key proteins implicated in linked pathways were identified using RT-qPCR, western blot analysis, and immunohistochemistry.

RESULTS

Network pharmacological predictions combined with animal experiments suggest that the model group compared to the control group, exhibited activation of the MAPK/ERK signaling pathway, suppression of hepcidin expression, and aggravated iron overload, liver damage, oxidative stress, and hepatocyte death. Puerarin and genistein, the active compounds in Pueraria lobata, effectively mitigated the aforementioned alcohol-induced effects. No statistically significant disparities were seen in the effects above between the two groups receiving drug therapy.

CONCLUSION

This study preliminarily demonstrated that puerarin and genistein in Pueraria lobata may increase hepcidin production to alleviate alcohol-induced iron overload by inhibiting the MAPK/ERK signaling pathway.

Association of HSD17B13 and PNPLA3 With Liver Enzymes and Fibrosis in Hispanic/Latino Individuals of Diverse Genetic Ancestries

BACKGROUND & AIMS

Genetic variants affecting liver disease risk vary among racial and ethnic groups. Hispanics/Latinos in the United States have a high prevalence of PNPLA3 I148M, which increases liver disease risk, and a low prevalence of HSD17B13 predicted loss-of-function (pLoF) variants, which reduce risk. Less is known about the prevalence of liver disease-associated variants among Hispanic/Latino subpopulations defined by country of origin and genetic ancestry. We evaluated the prevalence of HSD17B13 pLoF variants and PNPLA3 I148M, and their associations with quantitative liver phenotypes in Hispanic/Latino participants from an electronic health record-linked biobank in New York City.

METHODS

This study included 8739 adult Hispanic/Latino participants of the BioMe biobank with genotyping and exome sequencing data. We estimated the prevalence of Hispanic/Latino individuals harboring HSD17B13 and PNPLA3 variants, stratified by genetic ancestry, and performed association analyses between variants and liver enzymes and Fibrosis-4 (FIB-4) scores.

RESULTS

Individuals with ancestry from Ecuador and Mexico had the lowest frequency of HSD17B13 pLoF variants (10%/7%) and the highest frequency of PNPLA3 I148M (54%/65%). These ancestry groups had the highest outpatient alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and the largest proportion of individuals with a FIB-4 score greater than 2.67. HSD17B13 pLoF variants were associated with reduced ALT level (P = .002), AST level (P < .001), and FIB-4 score (P = .045). PNPLA3 I148M was associated with increased ALT level, AST level, and FIB-4 score (P < .001 for all). HSD17B13 pLoF variants mitigated the increase in ALT conferred by PNPLA3 I148M (P = .006).

CONCLUSIONS

Variation in HSD17B13 and PNPLA3 variants across genetic ancestry groups may contribute to differential risk for liver fibrosis among Hispanic/Latino individuals.

Sex difference in the association between blood alcohol concentration and serum ferritin

Introduction

The sex difference in alcohol use disorder (AUD) is ingrained in distinctive neurobiological responses between men and women, which necessitates further investigation for a more tailored management.

Methods

Minding the findings of iron dysregulation in AUD and the sex difference in iron homeostasis in multiple physiological and pathological settings, we examined the sex difference in the association between serum ferritin and blood alcohol concentration (BAC) in intoxicated males (n = 125) and females (n = 59). We included patients with both serum ferritin tested of any value and a BAC above the level of detection during the same hospital admission period. We investigated sex difference in the relationship between BAC, serum ferritin and liver enzymes in intoxicated critically ill and noncritically ill patients.

Results

We found a negative association between serum ferritin and BAC in critically ill, intoxicated females [R2 = 0.44, F(1,14) = 11.02, p = 0.005], with much attenuated serum ferritin in females compared to their male counterparts (194.5 ± 280.4 vs. 806.3 ± 3405.7 ng/L, p = 0.002). We found a positive association between serum ferritin and liver enzymes [alanine transaminase (ALT) and aspartate transferase (AST)] in critically ill intoxicated females [ALT: R2 = 0.48, F(1,10) = 9.1, p = 0.013; AST: R2 = 0.68, F(1,10) = 21.2, p = 0.001] and in noncritically ill intoxicated males [ALT: R2 = 0.1, F(1,83) = 9.4, p = 0.003; AST: R2 = 0.1, F(1,78) = 10.5, p = 0.002]. The effect of BAC on serum ferritin was not mediated by ALT [indirect effect: (B = 0.13, p = 0.1)]. We also found a significant effect of sex, anemia, intensive care unit (ICU) admission and mortality on serum ferritin.

Discussion

Our results suggest that high BAC in intoxicated female patients is associated with attenuated serum ferritin levels, questioning the role of low serum ferritin in female vulnerability to alcohol.

Genome-wide association mapping of ethanol sensitivity in the Diversity Outbred mouse population

BACKGROUND

A strong predictor for the development of alcohol use disorder (AUD) is altered sensitivity to the intoxicating effects of alcohol. Individual differences in the initial sensitivity to alcohol are controlled in part by genetic factors. Mice offer a powerful tool to elucidate the genetic basis of behavioral and physiological traits relevant to AUD, but conventional experimental crosses have only been able to identify large chromosomal regions rather than specific genes. Genetically diverse, highly recombinant mouse populations make it possible to observe a wider range of phenotypic variation, offer greater mapping precision, and thus increase the potential for efficient gene identification.

METHODS

We have taken advantage of the Diversity Outbred (DO) mouse population to identify and precisely map quantitative trait loci (QTL) associated with ethanol sensitivity. We phenotyped 798 male J:DO mice for three measures of ethanol sensitivity: ataxia, hypothermia, and loss of the righting response. We used high-density MegaMUGA and GigaMUGA to obtain genotypes ranging from 77,808 to 143,259 SNPs. We also performed RNA sequencing in striatum to map expression QTLs and identify gene expression-trait correlations. We then applied a systems genetic strategy to identify narrow QTLs and construct the network of correlations that exists between DNA sequence, gene expression values, and ethanol-related phenotypes to prioritize our list of positional candidate genes.

RESULTS

We observed large amounts of phenotypic variation with the DO population and identified suggestive and significant QTLs associated with ethanol sensitivity on chromosomes 1, 2, and 16. The implicated regions were narrow (4.5-6.9 Mb in size) and each QTL explained ~4-5% of the variance.

CONCLUSIONS

Our results can be used to identify alleles that contribute to AUD in humans, elucidate causative biological mechanisms, or assist in the development of novel therapeutic interventions.

HSD17B13: A Potential Therapeutic Target for NAFLD

Nonalcoholic fatty liver disease (NAFLD), especially in its inflammatory form (steatohepatitis, NASH), is closely related to the pathogenesis of chronic liver disease. Despite substantial advances in the management of NAFLD/NASH in recent years, there are currently no efficacious therapies for its treatment. The biogenesis and expansion of lipid droplets (LDs) are critical pathophysiological processes in the development of NAFLD/NASH. In the past decade, increasing evidence has demonstrated that lipid droplet-associated proteins may represent potential therapeutic targets for the treatment of NAFLD/NASH given the critical role they play in regulating the biogenesis and metabolism of lipid droplets. Recently, HSD17B13, a newly identified liver-enriched, hepatocyte-specific, lipid droplet-associated protein, has been reported to be strongly associated with the development and progression of NAFLD/NASH in both mice and humans. Notably, human genetic studies have repeatedly reported a robust association of HSD17B13 single nucleotide polymorphisms (SNPs) with the occurrence and severity of NAFLD/NASH and other chronic liver diseases (CLDs). Here we briefly overview the discovery, tissue distribution, and subcellular localization of HSD17B13 and highlight its important role in promoting the pathogenesis of NAFLD/NASH in both experimental animal models and patients. We also discuss the potential of HSD17B13 as a promising target for the development of novel therapeutic agents for NAFLD/NASH.

Alcohol-associated liver disease in the United States is associated with severe forms of disease among young, females and Hispanics

BACKGROUND

Alcohol use and alcohol-associated liver disease (ALD) burden are increasing in young individuals.

AIM

To assess host factors associated with this burden.

METHODS

National Health and Nutrition Examination Survey (NHANES), National Inpatient Sample (NIS), and United Network for Organ Sharing (UNOS) databases (2006-2016) were used to identify individuals with harmful alcohol use, ALD-related admissions, and ALD-related LT listings respectively.

RESULTS

Of 15 981 subjects in NHANES database, weighted prevalence of harmful alcohol use was 17.7%, 29.3% in <35 years (G1) versus 16.9% in 35-64 years (G2) versus 5.1% in ≥65 years (G3). Alcohol use was about 11 and 4.7 folds higher in G1 and G2 versus G3, respectively. Male gender and Hispanic race associated with harmful alcohol use. Of 593 600 ALD admissions (5%, 77%, and 18% in G1-G3 respectively), acute on chronic liver failure (ACLF) occurred in 7.2%, (7.2 in G2 vs 6.7% in G1 and G3, P < 0.001). After controlling for other variables, ACLF development among ALD hospitalizations was higher by 14% and 10% in G1 and G2 versus G3, respectively. Female gender and Hispanic race were associated with increased ACLF risk by 8% and 17% respectively. Of 20,245 ALD LT listings (3.4%, 84.4%, and 12.2% in G1-G3 respectively), ACLF occurred in 28% candidates. Risk of severe (grade 2 or 3) ACLF was higher by about 1.7 fold in G1, 1.5 fold in females and 20% in Hispanics.

CONCLUSION

Young age, female gender, and Hispanic race are independently associated with ALD-related burden and ACLF in the United States. If these findings are validated in prospective studies, strategies will be needed to reduce alcohol use in high risk individuals to reduce burden from ALD.

GWAS of serum ALT and AST reveals an association of SLC30A10 Thr95Ile with hypermanganesemia symptoms

Understanding mechanisms of hepatocellular damage may lead to new treatments for liver disease, and genome-wide association studies (GWAS) of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) serum activities have proven useful for investigating liver biology. Here we report 100 loci associating with both enzymes, using GWAS across 411,048 subjects in the UK Biobank. The rare missense variant SLC30A10 Thr95Ile (rs188273166) associates with the largest elevation of both enzymes, and this association replicates in the DiscovEHR study. SLC30A10 excretes manganese from the liver to the bile duct, and rare homozygous loss of function causes the syndrome hypermanganesemia with dystonia-1 (HMNDYT1) which involves cirrhosis. Consistent with hematological symptoms of hypermanganesemia, SLC30A10 Thr95Ile carriers have increased hematocrit and risk of iron deficiency anemia. Carriers also have increased risk of extrahepatic bile duct cancer. These results suggest that genetic variation in SLC30A10 adversely affects more individuals than patients with diagnosed HMNDYT1.

Long tracks of homozygosity predict the severity of alcohol use disorders in an American Indian population

Runs of homozygosity (ROH) arise when an individual inherits two copies of the same haplotype segment. While ROH are ubiquitous across human populations, Native populations-with shared parental ancestry arising from isolation and endogamy-can carry a substantial enrichment for ROH. We have been investigating genetic and environmental risk factors for alcohol use disorders (AUD) in a group of American Indians (AI) who have higher rates of AUD than the general U. S. population. Here we explore whether ROH might be associated with incidence and severity of AUD in this admixed AI population (n = 742) that live on geographically contiguous reservations, using low-coverage whole genome sequences. We have found that the genomic regions in the ROH that were identified in this population had significantly elevated American Indian heritage compared with the rest of the genome. Increased ROH abundance and ROH burden are likely risk factors for AUD severity in this AI population, especially in those diagnosed with severe and moderate AUD. The association between ROH and AUD was mostly driven by ROH of moderate lengths between 1 and 2 Mb. An ROH island on chromosome 1p32.3 and a rare ROH pool on chromosome 3p12.3 were found to be significantly associated with AUD severity. They contain genes involved in lipid metabolism, oxidative stress and inflammatory responses; and OSBPL9 was found to reside on the consensus part of the ROH island. These data demonstrate that ROH are associated with risk for AUD severity in this AI population.

Genome-wide Association Study and Meta-analysis on Alcohol-Associated Liver Cirrhosis Identifies Genetic Risk Factors

BACKGROUND AND AIMS

Only a minority of heavy drinkers progress to alcohol-associated cirrhosis (ALC). The aim of this study was to identify common genetic variants that underlie risk for ALC.

APPROACH AND RESULTS

We analyzed data from 1,128 subjects of European ancestry with ALC and 614 heavy-drinking subjects without known liver disease from Australia, the United States, the United Kingdom, and three countries in Europe. A genome-wide association study (GWAS) was performed, adjusting for principal components and clinical covariates (alcohol use, age, sex, body mass index, and diabetes). We validated our GWAS findings using UK Biobank. We then performed a meta-analysis combining data from our study, the UK Biobank, and a previously published GWAS. Our GWAS found genome-wide significant risk association of rs738409 in patatin-like phospholipase domain containing 3 (PNPLA3) (odds ratio [OR] = 2.19 [G allele], P = 4.93 × 10^-17 ) and rs4607179 near HSD17B13 (OR = 0.57 [C allele], P = 1.09 × 10^-10 ) with ALC. Conditional analysis accounting for the PNPLA3 and HSD17B13 loci identified a protective association at rs374702773 in Fas-associated factor family member 2 (FAF2) (OR = 0.61 [del(T) allele], P = 2.56 × 10^-8 ) for ALC. This association was replicated in the UK Biobank using conditional analysis (OR = 0.79, P = 0.001). Meta-analysis (without conditioning) confirmed genome-wide significance for the identified FAF2 locus as well as PNPLA3 and HSD17B13. Two other previously known loci (SERPINA1 and SUGP1/TM6SF2) were also genome-wide significant in the meta-analysis. GeneOntology pathway analysis identified lipid droplets as the target for several identified genes. In conclusion, our GWAS identified a locus at FAF2 associated with reduced risk of ALC among heavy drinkers. Like the PNPLA3 and HSD17B13 gene products, the FAF2 product has been localized to fat droplets in hepatocytes.

CONCLUSIONS

Our genetic findings implicate lipid droplets in the biological pathway(s) underlying ALC.

Gentiopicroside prevents alcoholic liver damage by improving mitochondrial dysfunction in the rat model

Gentianae Radix et Rhizoma is a medical plant that is widely cultivated in China, North Korea, Japan, and Russia, and gentiopicroside is one of its major active compounds. In this study, the hepatoprotective activity of gentiopicroside on rats with alcoholic liver damage (ALD) was evaluated using the transaminase and blood lipid levels and antioxidant capacity. The potential mechanism of hepatoprotective effect of gentiopicroside was evaluated by mitochondrial function detection, gas chromatography-mass spectrometry (GC-MS) metabolomic analysis, and anti-apoptosis analysis. Results showed that the gentiopicroside exhibited good hepatoprotective activity on rats with ALD by decreasing the transaminase levels, regulating the blood lipid levels, and increasing the antioxidant capacity. The potential mechanisms were related to regulating mitochondrial dysfunction by recovering mitochondrial membrane potential level, adenosine triphosphate concentration, activities of key enzymes in tricarboxylic acid cycle, and activities of complex I-V, regulating micromolecular metabolism and anti-apoptosis. These findings supported the further exploration of Gentianae Radix et Rhizoma as effective phytotherapy to prevent and treat ALD.

Insights into the aetiology of snoring from observational and genetic investigations in the UK Biobank

Although snoring is common in the general population, its aetiology has been largely understudied. Here we report a genetic study on snoring (n ~ 408,000; snorers ~ 152,000) using data from the UK Biobank. We identify 42 genome-wide significant loci, with an SNP-based heritability estimate of ~10% on the liability scale. Genetic correlations with body mass index, alcohol intake, smoking, schizophrenia, anorexia nervosa and neuroticism are observed. Gene-based associations identify 173 genes, including DLEU7, MSRB3 and POC5, highlighting genes expressed in the brain, cerebellum, lungs, blood and oesophagus. We use polygenic scores (PGS) to predict recent snoring and probable obstructive sleep apnoea (OSA) in an independent Australian sample (n ~ 8000). Mendelian randomization analyses suggest a potential causal relationship between high BMI and snoring. Altogether, our results uncover insights into the aetiology of snoring as a complex sleep-related trait and its role in health and disease beyond it being a cardinal symptom of OSA.

Snoring is common in the population and tends to be more prevalent in older and/or male individuals. Here, the authors perform GWAS for habitual snoring, identify 41 genomic loci and explore potential causal relationships with anthropometric and cardiometabolic disease traits.

A 17-Beta-Hydroxysteroid Dehydrogenase 13 Variant Protects From Hepatocellular Carcinoma Development in Alcoholic Liver Disease

Recently, a loss of function variant (rs72613567) in 17-beta-hydroxysteroid dehydrogenase 13 (HSD17B13) has been identified as protective of nonalcoholic (NAFLD) and alcoholic liver disease (ALD). However, the role of this single-nucleotide polymorphism (SNP) in the development of hepatocellular carcinoma (HCC) is currently unknown. A total of 3,315 European patients with HCC (n = 1,109) or without HCC, but with chronic liver disease (CLD; n = 2,206), from four centers were analyzed either by whole-exome sequencing (WES; exploratory cohort, 285 HCC) or genotyped for HSD17B13 rs72613567 (validation cohort, 824 HCC and all CLD). We included a control group of 33,337 healthy European individuals from the Exome Aggregation Consortium. We compared distribution of genotype using the chi-square test and logistic regression. In the exploratory cohort analyzed by WES, frequency of the TA allele of HSD17B13 rs72613567 was significantly decreased in HCC patients compared to healthy controls (P = 1.52 × 10^-06 ). In the validation cohort, frequency of TA allele carriers was also decreased in patients with CLD and without HCC (39%) compared to healthy individuals (47%; P < 0.0001). The protective effect of the TA allele of HSD17B13 rs72613567 was identified in patients with ALD (odds ratio [OR] = 0.73; 95% confidence interval [CI], 0.65-0.82; P < 0.0001), NAFLD (OR = 0.64; 95% CI, 0.49-0.83; P = 0.0007), and hepatitis C (OR = 0.71; 95% CI, 0.60-0.85; P = 0.0002). In patients with ALD, the proportion of TA allele carriers with HCC was significantly lower (32%) than in CLD patients without HCC (40%), even after adjustment for age, sex, and fibrosis (OR = 0.64; 95% CI, 0.46-0.87; P = 0.005). Conclusion: The HSD17B13 rs72613567 loss of function variant is protective of HCC development in patients with ALD.

Translational Metabolomics: Current Challenges and Future Opportunities

Metabolomics is one of the latest omics technologies that has been applied successfully in many areas of life sciences. Despite being relatively new, a plethora of publications over the years have exploited the opportunities provided through this data and question driven approach. Most importantly, metabolomics studies have produced great breakthroughs in biomarker discovery, identification of novel metabolites and more detailed characterisation of biological pathways in many organisms. However, translation of the research outcomes into clinical tests and user-friendly interfaces has been hindered due to many factors, some of which have been outlined hereafter. This position paper is the summary of discussion on translational metabolomics undertaken during a peer session of the Australian and New Zealand Metabolomics Conference (ANZMET 2018) held in Auckland, New Zealand. Here, we discuss some of the key areas in translational metabolomics including existing challenges and suggested solutions, as well as how to expand the clinical and industrial application of metabolomics. In addition, we share our perspective on how full translational capability of metabolomics research can be explored.

Serum iron, Magnesium, Copper, and Manganese Levels in Alcoholism: A Systematic Review

The aim of this paper was to review recent literature (from 2000 onwards) and summarize the newest findings on fluctuations in the concentration of some essential macro- and microelements in those patients with a history of chronic alcohol abuse. The focus was mainly on four elements which the authors found of particular interest: Iron, magnesium, copper, and manganese. After independently reviewing over 50 articles, the results were consistent with regard to iron and magnesium. On the other hand, data were limited, and in some cases contradictory, as far as copper and manganese were concerned. Iron overload and magnesium deficiency are two common results of an excessive and prolonged consumption of alcohol. An increase in the levels of iron can be seen both in the serum and within the cells, hepatocytes in particular. This is due to a number of factors: Increased ferritin levels, lower hepcidin levels, as well as some fluctuations in the concentration of the TfR receptor for transferrin, among others. Hypomagnesemia is universally observed among those suffering from alcoholism. Again, the causes for this are numerous and include malnutrition, drug abuse, respiratory alkalosis, and gastrointestinal problems, apart from the direct influence of excessive alcohol intake. Unfortunately, studies regarding the levels of both copper and manganese in the case of (alcoholic) liver disease are scarce and often contradictory. Still, the authors have attempted to summarize and give a thorough insight into the literature available, bearing in mind the difficulties involved in the studies. Frequent comorbidities and mutual relationships between the elements in question are just some of the complications in the study of this topic.