There is increasing evidence for the role of gut microbial composition in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Nonalcoholic steatohepatitis (NASH) is the most serious form of NAFLD where inflammation causes liver damage that can progress to cirrhosis. We have characterized the gut microbiome composition in UK patients with biopsy-proven NASH (n = 65) and compared it to that in healthy controls (n = 76). We report a 7% lower Shannon alpha diversity in NASH patients without cirrhosis (n = 40) compared to controls (p = 2.7x 10⁻⁴) and a 14% drop in NASH patients with cirrhosis (n = 25, p = 5.0x 10⁻⁴). Beta diversity (Unweighted UniFrac distance) was also significantly reduced in both NASH (p = 5.6x 10⁻²⁵) and NASH-cirrhosis (p = 8.1x 10⁻⁷) groups. The genus most strongly associated with NASH in this study was Collinsella (0.29% abundance in controls, 3.45% in NASH without cirrhosis (False Discovery Rate (FDR) p = .008), and 4.38% in NASH with cirrhosis (FDR p = .02)). This genus, which has been linked previously to obesity and atherosclerosis, was also positively correlated with fasting levels of triglycerides (p = .01) and total cholesterol (p = 1.2x 10⁻⁴) and negatively correlated with high-density lipoprotein cholesterol (p = 2.8x 10⁻⁶) suggesting that some of the pathways present in this microbial genus may influence lipid metabolism in the host. In patients, we also found decreased abundance of some of the Ruminococcaceae which are known to produce high levels of short-chain fatty acids which can lower inflammation. This may thus contribute to pathology associated with NASH.

Background & Aims We performed a genome-wide association study (GWAS) to identify genetic risk factors for drug-induced liver injury (DILI) from licensed drugs without previously reported genetic risk factors. Methods We performed a GWAS of 862 persons with DILI and 10,588 population-matched controls. The first set of cases was recruited before May 2009 in Europe (n = 137) and the United States (n = 274). The second set of cases were identified from May 2009 through May 2013 from international collaborative studies performed in Europe, the United States, and South America. For the GWAS, we included only cases with patients of European ancestry associated with a particular drug (but not flucloxacillin or amoxicillin-clavulanate). We used DNA samples from all subjects to analyze HLA genes and single nucleotide polymorphisms. After the discovery analysis was concluded, we validated our findings using data from 283 European patients with diagnosis of DILI associated with various drugs. Results We associated DILI with rs114577328 (a proxy for A*33:01 a HLA class I allele; odds ratio [OR], 2.7; 95% confidence interval [CI], 1.9−3.8; P = 2.4 × 10⁻⁸) and with rs72631567 on chromosome 2 (OR, 2.0; 95% CI, 1.6−2.5; P = 9.7 × 10⁻⁹). The association with A*33:01 was mediated by large effects for terbinafine-, fenofibrate-, and ticlopidine-related DILI. The variant on chromosome 2 was associated with DILI from a variety of drugs. Further phenotypic analysis indicated that the association between DILI and A*33:01 was significant genome wide for cholestatic and mixed DILI, but not for hepatocellular DILI; the polymorphism on chromosome 2 was associated with cholestatic and mixed DILI as well as hepatocellular DILI. We identified an association between rs28521457 (within the lipopolysaccharide-responsive vesicle trafficking, beach and anchor containing gene) and only hepatocellular DILI (OR, 2.1; 95% CI, 1.6−2.7; P = 4.8 × 10⁻⁹). We did not associate any specific drug classes with genetic polymorphisms, except for statin-associated DILI, which was associated with rs116561224 on chromosome 18 (OR, 5.4; 95% CI, 3.0−9.5; P = 7.1 × 10⁻⁹). We validated the association between A*33:01 terbinafine- and sertraline-induced DILI. We could not validate the association between DILI and rs72631567, rs28521457, or rs116561224. Conclusions In a GWAS of persons of European descent with DILI, we associated HLA-A*33:01 with DILI due to terbinafine and possibly fenofibrate and ticlopidine. We identified polymorphisms that appear to be associated with DILI from statins, as well as 2 non−drug-specific risk factors.

Hepatic iron has been associated with more aggressive liver disease in chronic viral hepatitis. We evaluated whether the recently described C282Y mutation of the hemochromatosis gene, designated HFE (responsible for at least 83% of hereditary hemochromatosis), was associated with more advanced liver disease in chronic hepatitis C. One hundred thirty-seven patients with biopsy-proven chronic hepatitis C were studied and liver biopsies scored for necroinflammation (grade 0-18) and fibrosis (stage 0-6). Genomic DNA was amplified by polymerase chain reaction and the C282Y mutation identified by restriction with RsaI and electrophoretic separation of restriction fragments. Ten (7.3%) patients had the C282Y mutation. No C282Y homozygous patients were identified. Age, sex distribution, and estimated weekly alcohol consumption were not significantly different between those with and without the mutation. Serum ferritin was higher in the heterozygotes (mean, 339 μg/L) compared with homozygous wild types (153 μg/L; P = .0005). In the majority of patients, liver iron was graded 0 out of 4, but hepatocyte iron staining was more commonly present in heterozygotes compared with homozygous normals (30% compared with 4% [P = .02]). Liver disease was more advanced in those with the mutant allele (mean fibrosis stage: 3.6, compared with wild type: 1.5 [P = .01]). Cirrhosis was found more often in those with the mutation (40%) compared with those without (8.7%) (P = .01; odds ratio: 7.6 [1.9-31.2]). There was no significant difference in inflammation scores between heterozygotes and wild type (mean, 5.4 compared with 4.1). Hepatitis C virus (HCV)-RNA titers were measured by branched DNA assay (HCV RNA 2.0-Chiron), and there was no difference between heterozygous and homozygous normal patients. Thus, despite relatively minor increases in iron stores, individuals who are heterozygous for hemochromatosis appear to develop more fibrosis in chronic hepatitis C. Venesection may be useful therapy in this subgroup.

BACKGROUND The factors determining why less than 10% of heavy drinkers develop advanced alcoholic liver disease (ALD) remain elusive, although genetic factors may be important. Interleukin 10 (IL-10) is an important cytokine with anti-inflammatory, anti-immune, and antifibrotic functions. Several polymorphisms have been identified in the IL-10 promoter and recent evidence suggests that some of these may have functional effects on IL-10 secretion. AIMS To test the hypothesis that IL-10 promoter region polymorphisms are associated with susceptibility to ALD. METHODS The allele frequencies for the two single base pair substitutions at positions −627 (C→A) and −1117 (A→G) in the IL-10 promoter were determined in 287 heavy drinkers with biopsy proved advanced ALD, 107 heavy drinkers with no evidence of liver disease or steatosis only on biopsy, and 227 local healthy volunteers. RESULTS At position −627, 50% of patients with advanced ALD had a least one A allele compared with 33% of controls (p<0.0001) and 34% of drinkers with no or mild disease (p=0.017). At position −1117, the slight excess of the A allele in drinkers with advanced disease was because of linkage disequilibrium between the A alleles at the two sites. CONCLUSIONS Among heavy drinkers, possession of the A allele at position −627 in the IL-10 promoter is associated with an increased risk of advanced liver disease. This is consistent with recent functional data that the −627*A allele is associated with low IL-10 expression which will favour inflammatory, immune mediated, and profibrotic mechanisms of alcohol related liver injury.