Programmed cell death 1 genetic variant and liver damage in nonalcoholic fatty liver disease.

BACKGROUND AND AIMS: Programmed cell death 1/programmed cell death-ligand 1 (PD-1/PDL-1) axis has been reported to modulate liver inflammation and progression to hepatocellular carcinoma (HCC) in patients with nonalcoholic fatty liver disease (NAFLD). Here, we examined whether the PDCD1 variation is associated with NAFLD severity in individuals with liver biopsy. METHODS: We examined the impact of PDCD1 gene variants on HCC, as robust severe liver disease phenotype in UK Biobank participants. The strongest genetic association with the rs13023138 G>C variation was subsequently tested for association with liver damage in 2889 individuals who underwent liver biopsy for suspected nonalcoholic steatohepatitis (NASH). Hepatic transcriptome was examined by RNA-Seq in a subset of NAFLD individuals (n = 121). Transcriptomic and deconvolution analyses were performed to identify biological pathways modulated by the risk allele. RESULTS: The rs13023138 C>G showed the most robust association with HCC in UK Biobank (p = 5.28E-4, OR = 1.32, 95% CI [1.1, 1.5]). In the liver biopsy cohort, rs13023138 G allele was independently associated with severe steatosis (OR 1.17, 95% CI 1.02-1.34; p = .01), NASH (OR 1.22, 95% CI 1.09-1.37; p < .001) and advanced fibrosis (OR 1.26, 95% CI 1.06-1.50; p = .007). At deconvolution analysis, rs13023138 G>C allele was linked to higher hepatic representation of M1 macrophages, paralleled by upregulation of pathways related to inflammation and higher expression of CXCR6. CONCLUSIONS: The PDCD1 rs13023138 G allele was associated with HCC development in the general population and with liver disease severity in patients at high risk of NASH.

Rare ATG7 genetic variants predispose patients to severe fatty liver disease.

BACKGROUND & AIMS: Non-alcoholic fatty liver disease (NAFLD) is the leading cause of liver disorders and has a strong heritable component. The aim of this study was to identify new loci that contribute to severe NAFLD by examining rare variants. METHODS: We performed whole-exome sequencing in individuals with NAFLD and advanced fibrosis or hepatocellular carcinoma (n = 301) and examined the enrichment of likely pathogenic rare variants vs. the general population. This was followed by validation at the gene level. RESULTS: In patients with severe NAFLD, we observed an enrichment of the p.P426L variant (rs143545741 C>T; odds ratio [OR] 5.26, 95% CI 2.1-12.6; p = 0.003) of autophagy-related 7 (ATG7), which we characterized as a loss-of-function, vs. the general population, and an enrichment in rare variants affecting the catalytic domain (OR 13.9; 95% CI 1.9-612; p = 0.002). In the UK Biobank cohort, loss-of-function ATG7 variants increased the risk of cirrhosis and hepatocellular carcinoma (OR 3.30; 95% CI 1.1-7.5 and OR 12.30, 95% CI 2.6-36, respectively; p <0.001 for both). The low-frequency loss-of-function p.V471A variant (rs36117895 T>C) was also associated with severe NAFLD in the clinical cohort (OR 1.7; 95% CI 1.2-2.5; p = 0.003), predisposed to hepatocellular ballooning (p = 0.007) evolving to fibrosis in the Liver biopsy cohort (n = 2,268), and was associated with liver injury in the UK Biobank (aspartate aminotransferase levels, p <0.001), with a larger effect in severely obese individuals in whom it was linked to hepatocellular carcinoma (p = 0.009). ATG7 protein localized to periportal hepatocytes, particularly in the presence of ballooning. In the Liver Transcriptomic cohort (n = 125), ATG7 expression correlated with suppression of the TNFα pathway, which was conversely upregulated in p.V471A carriers. CONCLUSIONS: We identified rare and low-frequency ATG7 loss-of-function variants that promote NAFLD progression by impairing autophagy and facilitating ballooning and inflammation. LAY SUMMARY: We found that rare mutations in a gene called autophagy-related 7 (ATG7) increase the risk of developing severe liver disease in individuals with dysmetabolism. These mutations cause an alteration in protein function and impairment of self-renewal of cellular content, leading to liver damage and inflammation.

Subclinical and clinical atherosclerosis in non-alcoholic fatty liver disease is associated with the presence of hypertension.

BACKGROUND AND AIMS: Non-alcoholic fatty liver disease (NAFLD) is associated with increased cardiovascular (CV) risk. However, it is unclear whether NAFLD contributes independently to the development of CV disease. Our study aimed at assessing the differences in several indices of atherosclerosis, arterial stiffness and cardiac morphology among patients with isolated NAFLD, isolated hypertension (HT) or a combination of the two conditions. METHODS AND RESULTS: A total of 169 participants (mean age = 50.4 ± 10.2 yrs; males = 73.6%) were divided according to the presence of NAFLD and HT into three groups: only NAFLD (55 patients), only HT (49 patients), and NAFLD + HT (65 patients). Exclusion criteria were a BMI≥35 kg/m2 and a diagnosis of diabetes mellitus. Carotid ultrasonography was performed to measure markers of atherosclerosis and arterial stiffness. Cardiac remodeling was analyzed using echocardiography. The prevalence of subclinical and overt atherosclerosis was significantly higher in the NAFLD + HT patients as compared to the other two groups (atherosclerotic plaques: 43.1%, 10.9%, and 22.4% (p < 0.001) in NAFLD + HT, NAFLD, and HT groups, respectively). No differences were found among indices of arterial stiffening and cardiac remodeling across the three groups. In multivariate regression analysis, the coexistence of NAFLD and HT was an independent risk factor for overt atherosclerosis (OR = 4.88, CI 95% 1.14-20.93), while no association was found when either NAFLD or HT was considered alone. CONCLUSION: Overt atherosclerosis was significantly present only in NAFLD + HT patients, but not in patients with isolated NAFLD. This implies that the impact of NAFLD on vascular structure and function could depend on the coexistence of other major CV risk factors, such as HT.

Long-term outcomes and predictive ability of non-invasive scoring systems in patients with non-alcoholic fatty liver disease.

BACKGROUND & AIMS: Non-invasive scoring systems (NSS) are used to identify patients with non-alcoholic fatty liver disease (NAFLD) who are at risk of advanced fibrosis, but their reliability in predicting long-term outcomes for hepatic/extrahepatic complications or death and their concordance in cross-sectional and longitudinal risk stratification remain uncertain. METHODS: The most common NSS (NFS, FIB-4, BARD, APRI) and the Hepamet fibrosis score (HFS) were assessed in 1,173 European patients with NAFLD from tertiary centres. Performance for fibrosis risk stratification and for the prediction of long-term hepatic/extrahepatic events, hepatocarcinoma (HCC) and overall mortality were evaluated in terms of AUC and Harrell's c-index. For longitudinal data, NSS-based Cox proportional hazard models were trained on the whole cohort with repeated 5-fold cross-validation, sampling for testing from the 607 patients with all NSS available. RESULTS: Cross-sectional analysis revealed HFS as the best performer for the identification of significant (F0-1 vs. F2-4, AUC = 0.758) and advanced (F0-2 vs. F3-4, AUC = 0.805) fibrosis, while NFS and FIB-4 showed the best performance for detecting histological cirrhosis (range AUCs 0.85-0.88). Considering longitudinal data (follow-up between 62 and 110 months), NFS and FIB-4 were the best at predicting liver-related events (c-indices>0.7), NFS for HCC (c-index = 0.9 on average), and FIB-4 and HFS for overall mortality (c-indices >0.8). All NSS showed limited performance (c-indices <0.7) for extrahepatic events. CONCLUSIONS: Overall, NFS, HFS and FIB-4 outperformed APRI and BARD for both cross-sectional identification of fibrosis and prediction of long-term outcomes, confirming that they are useful tools for the clinical management of patients with NAFLD at increased risk of fibrosis and liver-related complications or death. LAY SUMMARY: Non-invasive scoring systems are increasingly being used in patients with non-alcoholic fatty liver disease to identify those at risk of advanced fibrosis and hence clinical complications. Herein, we compared various non-invasive scoring systems and identified those that were best at identifying risk, as well as those that were best for the prediction of long-term outcomes, such as liver-related events, liver cancer and death.

Presence of Serum Antinuclear Antibodies Does Not Impact Long-Term Outcomes in Nonalcoholic Fatty Liver Disease.

INTRODUCTION: We investigated the longitudinal impact of antinuclear antibody (ANA) on clinical outcomes and survival in nonalcoholic fatty liver disease (NAFLD). METHODS: ANA were found in 16.9% of 923 biopsy-proven NAFLD patients, but none of them had histologic autoimmune hepatitis (AIH) or developed AIH after a mean follow-up of 106±50 months. RESULTS: Although ANA-positive cases had a higher prevalence of nonalcoholic steatohepatitis at baseline, the occurrence of liver-related events, hepatocellula carcinoma, cardiovascular events, extrahepatic malignancy, and overall survival were similar to ANA-negative. DISCUSSION: Once AIH has been ruled out, the long-term outcomes and survival are unaffected by the presence of ANA in patients with NAFLD.

Liver fibrosis by FibroScan® independently of established cardiovascular risk parameters associates with macrovascular and microvascular complications in patients with type 2 diabetes.

BACKGROUND & AIMS: Non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) are closely associated, and liver fibrosis has been related to macrovascular complications. We examined whether liver fibrosis, diagnosed by FibroScan® , correlates with chronic vascular complications in a cohort of T2DM. METHODS: We recruited 394 outpatients with T2DM attending five Italian diabetes centres who underwent liver ultrasonography (US), FibroScan® and extensive evaluation of macrovascular and microvascular diabetic complications. RESULTS: Steatosis by US was present in 89%. Almost all patients (96%) were on hypoglycaemic drugs, 58% had at least one chronic vascular complication, 19% a macrovascular complication (prior myocardial infarction and/or ischaemic stroke) and 33% a microvascular one (26% chronic kidney disease [CKD]; 16% retinopathy; 6% neuropathy). In all, 171 (72%) patients had CAP ≥ 248dB/m (ie hepatic steatosis), whereas 83 (21%) patients had LSM ≥ 7.0/6.2 kPa (M/XL probes) (significant liver fibrosis). CAP was not associated with any macro/microvascular complications, whereas LSM ≥ 7.0/6.2 kPa was independently associated with prior cardiovascular disease (adjusted OR 3.3, 95%CI 1.2-8.8; P = .02) and presence of microvascular complications (adjusted OR 4.2, 95%CI 1.5-11.4; P = .005), mainly CKD (adjusted OR 3.6, 95%CI 1.3-10.1; P = .01) and retinopathy (adjusted OR 3.7, CI 95% 1.2-11.9; P = .02). Neither diabetes duration nor haemoglobin A1c differed according to CAP or LSM values. CONCLUSION: Significant fibrosis, detected by FibroScan® , is independently associated with increased prevalence of macrovascular and microvascular complications, thus opening a new scenario in the use of this tool for a comprehensive evaluation of hepatic and vascular complications in patients with T2DM.

Reduced incidence of type 2 diabetes in patients with chronic hepatitis C virus infection cleared by direct-acting antiviral therapy: A prospective study.

AIM: To assess the effect of hepatitis C virus (HCV) eradication on type 2 diabetes mellitus (T2DM). incidence. METHODS: A prospective multicentre case-control study was performed, which included 2426 patients with HCV, 42% of whom had liver fibrosis stage F0-F2 and 58% of whom had liver fibrosis stage F3-F4. The study population consisted of a control group including 1099 untreated patients and 1327 cases treated with direct-acting antivirals (DAAs). T2DM incidence was assessed during a median (interquartile range) follow-up period of 30 (28-42) months. Risk factors for T2DM were assessed using a Cox regression model (relative risk [RR], hazard ratio [HR], Kaplan-Meier analysis). Insulin sensitivity was evaluated by homeostatic model assessment (HOMA) and changes by repeated-measures ANOVA. Factors independently associated with T2DM were assessed by multivariate analysis. RESULTS: The absolute incidence of T2DM for controls and cases was 28 and 7/1000 person-years, respectively (P = 0.001). In cases compared to controls, HCV clearance reduced the RR and HR of T2DM by 81% and 75% to 93%, respectively (P = 0.001). It was calculated that, for every 15 patients who obtained HCV clearance, one case of T2DM was saved. HCV clearance was associated with significant reductions in HOMA-insulin resistance and HOMA-ß-cell function and an increase in HOMA-insulin sensitivity, as assessed in 384 patients before and after HCV clearance. At multivariate analysis, HCV clearance emerged as independently associated with a reduced T2DM risk. CONCLUSION: The results showed that HCV clearance by DAA treatment reduces T2DM incidence probably by restoring the HCV-induced alteration of glucose homeostasis mechanisms.

Impact of natural neuromedin-B receptor variants on iron metabolism.

Iron overload heritability remains partly unexplained. By performing whole exome sequencing in three patients with a clinical phenotype of hemochromatosis not accounted by known genetic risk factors, we identified in all patients rare variants predicted to alter activity of Neuromedin-B receptor (NMBR). Coding NMBR mutations were enriched in 129 patients with hereditary hemochromatosis or iron overload phenotype, as compared to ethnically matched controls, including 100 local healthy blood donors and 1000Genomes project participants (15.5% vs 5%, P = .0038 at burden test), and were associated with higher transferrin saturation in regular blood donors (P = .04). Consistently, in 191 patients with nonalcoholic fatty liver, the most common low-frequency p.L390 M variant was independently associated with higher ferritin (P = .03). In 58 individuals, who underwent oral iron challenge, carriage of the p.L390 M variant was associated with higher transferrin saturation and lower hepcidin release. Furthermore, the circulating concentration of the natural NMBR ligand, Neuromedin-B, was reduced in response to iron challenge. It was also decreased in individuals carrying the p.L390 M variant and with hemochromatosis in parallel with increased transferrin saturation. In mice, Nmbr was induced by chronic dietary iron overload in the liver, gut, pancreas, spleen, and skeletal muscle, while Nmb was downregulated in gut, pancreas and spleen. Finally, Nmb amplified holo-transferrin dependent induction of hepcidin in primary mouse hepatocytes, which was associated with Jak2 induction and abolished by the NMBR antagonist PD168368. In conclusion, NMBR natural variants were enriched in patients with iron overload, and associated with facilitated iron absorption, possibly related to a defect of iron-induced hepcidin release.

Procoagulant imbalance in patients with non-alcoholic fatty liver disease.

BACKGROUND & AIMS: Non-alcoholic fatty liver disease (NAFLD) is characterized by increased risk of cardiovascular events and liver-fibrosis. Both could be explained by a procoagulant-imbalance that was surmised but never directly demonstrated. We investigated 113 patients with varying histological liver damage [steatosis (n=32), steatohepatitis (n=51), metabolic-cirrhosis (n=30)], 54 with alcoholic/viral-cirrhosis and 179 controls. METHODS: Plasma was evaluated for levels of pro- and anti-coagulants, and for thrombin-generation assessed as endogenous-thrombin-potential (ETP) with and without thrombomodulin or Protac® as protein C activators. The procoagulant-imbalance was defined as ETP-ratio (with-to-without thrombomodulin) or as Protac®-induced-coagulation-inhibition (PICI%). High ETP-ratios or low PICI% indicate resistance to thrombomodulin or Protac® and hence a procoagulant-imbalance. RESULTS: ETP-ratio increased from controls [0.57 (0.11-0.89)] to steatosis [0.72 (0.33-0.86)] and metabolic-cirrhosis [0.80 (0.57-0.95)], (p<0.001), the latter being comparable to that for alcoholic/viral-cirrhosis [0.80 (0.57-0.95) vs. 0.80 (0.44-0.96)]. Factor VIII (a potent procoagulant for thrombin-generation) increased from steatosis [99% (71-150)] to metabolic-cirrhosis [157% (64-232)], p<0.001. Protein C (a powerful anticoagulant) decreased from steatosis [103% (77-228)] to metabolic-cirrhosis [77 (17-146)], p<0.001. As a consequence, factor VIII-to-protein C ratio increased from steatosis [0.96 (0.36-1.60)] to metabolic-cirrhosis [2.05 (0.81-12.1)], p<0.001 and was correlated with the ETP-ratio (rho=0.543, p<0.001). Similar results were obtained for PICI%. Patients with procoagulant-imbalance detected as ETP-ratio greater or PICI% lower than the median value of controls tended to have a higher risk of metabolic-syndrome, higher intima-media thickness, fibrosis, steatosis or lobular inflammation, all considered clinical manifestations of NAFLD. CONCLUSION: NAFLD is characterized by a procoagulant-imbalance progressing from the less severe (steatosis) to the most severe form of the disease (metabolic-cirrhosis). This imbalance appears to result from increased factor VIII and reduced protein C and might play a role in the risk of cardiovascular events and liver-fibrosis commonly observed in NAFLD.

Hepatic steatosis and PNPLA3 I148M variant are associated with serum Fetuin-A independently of insulin resistance.

BACKGROUND & AIMS: Fetuin-A is a liver-derived peptide associated with insulin resistance. Aim of this cross-sectional study was to evaluate whether Fetuin-A is increased in patients with nonalcoholic fatty liver disease (NAFLD) vs. healthy subjects without metabolic abnormalities and the association with insulin resistance and liver damage. To investigate the causal relationship between fatty liver and Fetuin-A, we also analysed whether the inherited I148M PNPLA3 variant modulates Fetuin-A. METHODS: In 137 patients with histological NAFLD, complete metabolic characterization, PNPLA3 genotype, and in 260 healthy subjects without metabolic alterations, Fetuin-A was measured by enzyme-linked immunoabsorbent assay. RESULTS: Serum Fetuin-A was higher in NAFLD patients than in controls (P < 0·0001), independently of age, sex, BMI, insulin resistance, dyslipidemia, adiponectin, PNPLA3 I148M and ALT levels (OR 1·006 95% CI 1·003-1·11; P = 0·003). In NAFLD patients, Fetuin-A was associated with steatosis severity (P = 0·03) and metabolic syndrome features, but not with hepatic inflammation. At multivariate analysis, Fetuin-A levels were associated with BMI, triglycerides, hyperglycemia and PNPLA3 I148M (P = 0·034) independently also of age, sex and ALT levels. As PNPLA3 I148M is a strong and inherited determinant of liver fat without affecting insulin resistance and lipid levels, these data suggest that steatosis has a causal role in determining serum Fetuin-A levels. CONCLUSIONS: Liver fat accumulation and the I148M variant of PNPLA3 are associated with serum Fetuin-A levels independently of insulin resistance. Fetuin-A may be implicated in the pathogenesis of metabolic complications associated with NAFLD.