R. Rametta

The MBOAT7-TMC4 Variant rs641738 Increases Risk of Nonalcoholic Fatty Liver Disease in Individuals of European Descent.

BACKGROUND & AIMS Nonalcoholic fatty liver disease (NAFLD) is a leading cause of liver damage and is characterized by steatosis. Genetic factors increase risk for progressive NAFLD. A genome-wide association study showed that the rs641738 C>T variant in the locus that contains the membrane bound O-acyltransferase domain-containing 7 gene (MBOAT7, also called LPIAT1) and transmembrane channel-like 4 gene (TMC4) increased the risk for cirrhosis in alcohol abusers. We investigated whether the MBOAT7-TMC4 is a susceptibility locus for the development and progression of NAFLD. METHODS We genotyped rs641738 in DNA collected from 3854 participants from the Dallas Heart Study (a multi-ethnic population-based probability sample of Dallas County residents) and 1149 European individuals from the Liver Biopsy Cross-Sectional Cohort. Clinical and anthropometric data were collected, and biochemical and lipidomics were measured in plasma samples from participants. A total of 2736 participants from the Dallas Heart Study also underwent proton magnetic resonance spectroscopy to measure hepatic triglyceride content. In the Liver Biopsy Cross-Sectional Cohort, a total of 1149 individuals underwent liver biopsy to diagnose liver disease and disease severity. RESULTS The genotype rs641738 at the MBOAT7-TMC4 locus associated with increased hepatic fat content in the 2 cohorts, and with more severe liver damage and increased risk of fibrosis compared with subjects without the variant. MBOAT7, but not TMC4, was found to be highly expressed in the liver. The MBOAT7 rs641738 T allele was associated with lower protein expression in the liver and changes in plasma phosphatidylinositol species consistent with decreased MBOAT7 function. CONCLUSIONS We provide evidence for an association between the MBOAT7 rs641738 variant and the development and severity of NAFLD in individuals of European descent. This association seems to be mediated by changes in the hepatic phosphatidylinositol acyl-chain remodeling.

Serum ferritin levels are associated with vascular damage in patients with nonalcoholic fatty liver disease

BACKGROUND AND AIMS Increased ferritin and body iron stores are frequently observed in nonalcoholic fatty liver disease (NAFLD), associated with heightened susceptibility to vascular damage. Conflicting data have been reported on the role of iron in atherosclerosis, with recent data suggesting that excess iron induces vascular damage by increasing levels of the hormone hepcidin, which would determine iron trapping into macrophages, oxidative stress, and promotion of transformation into foam cells. Aim of this study was to investigate the relationship between iron status and cardiovascular damage in NAFLD. METHODS AND RESULTS Vascular damage was evaluated by common carotid arteries intima-media thickness (CC-IMT) measurement and plaque detection by ecocolor-doppler ultrasonography in 506 patients with clinical and ultrasonographic diagnosis of NAFLD, hemochromatosis gene (HFE) mutations by restriction analysis in 342 patients. Serum hepcidin-25 was measured by time-of-flight mass spectrometry in 143 patients. At multivariate analysis CC-IMT was associated with systolic blood pressure, glucose, LDL cholesterol, abdominal circumference, age, and ferritin (p=0.048). Carotid plaques were independently associated with age, ferritin, glucose, and hypertension. Ferritin reflected iron stores and metabolic syndrome components, but not inflammation or liver damage. Hyperferritinemia was associated with increased vascular damage only in patients with HFE genotypes associated with hepcidin upregulation by iron stores (p<0.0001), and serum hepcidin-25 was independently associated with carotid plaques (p=0.05). CONCLUSION Ferritin levels, reflecting iron stores, are independent predictors of vascular damage in NAFLD. The mechanism may involve upregulation of hepcidin by increased iron stores in patients not carrying HFE mutations, and iron compartmentalization into macrophages.

A tetra‐primer amplification refractory mutation system polymerase chain reaction for the evaluation of rs12979860 IL28B genotype

Summary.  Recently, genome‐wide association studies in patients affected by HCV infection have identified a strong association between sustained virological response to peg‐interferon/ribavirin and spontaneous viral clearance and common single nucleotide polymorphisms (SNPs) near the IL28B gene, encoding for interferon‐lambda‐3. Thus, it is anticipated that IL28B genotype determination will be integrated in clinical practice to guide treatment decisions. Here, we describe a simple tetra‐primer amplification refractory mutation system polymerase chain reaction (T‐ARMS‐PCR) for the evaluation of the rs12979860 C>T IL28B SNP, for which strong evidence of association with clinical outcomes has been collected in subjects of European descent. Valid genotypic data were obtained for over 99% of subjects analysed, and T‐ARMS‐PCR procedures were validated by the analysis of DNA samples of 164 patients with chronic HCV infection. In conclusion, this method allows rapid, reproducible, inexpensive and accurate detection of rs12979860 polymorphism without need of any special equipment and is also suitable for evaluation of a low number of samples on a routine basis.

The rs2294918 E434K variant modulates patatin-like phospholipase domain-containing 3 expression and liver damage.

The patatin‐like phosholipase domain‐containing 3 (PNPLA3) rs738409 polymorphism (I148M) is a major determinant of hepatic fat and predisposes to the full spectrum of liver damage in nonalcoholic fatty liver disease (NAFLD). The aim of this study was to evaluate whether additional PNPLA3 coding variants contribute to NAFLD susceptibility, first in individuals with contrasting phenotypes (with early‐onset NAFLD vs. very low aminotransferases) and then in a large validation cohort. Rare PNPLA3 variants were not detected by sequencing coding regions and intron‐exon boundaries either in 142 patients with early‐onset NAFLD nor in 100 healthy individuals with alanine aminotransferase <22/20 IU/mL. Besides rs738409 I148M, the rs2294918 G>A polymorphism (E434K sequence variant) was over‐represented in NAFLD (adjusted P = 0.01). In 1,447 subjects with and without NAFLD, the 148M‐434E (P < 0.0001), but not the 148M‐434K, haplotype (P > 0.9), was associated with histological NAFLD and steatohepatitis. Both the I148M (P = 0.0002) and E434K variants (P = 0.044) were associated with serum ALT levels, by interacting with each other, in that the 434K hampered the association with liver damage of the 148M allele (P = 0.006). The E434K variant did not affect PNPLA3 enzymatic activity, but carriers of the rs2294918 A allele (434K) displayed lower hepatic PNPLA3 messenger RNA and protein levels (P < 0.05). Conclusions: Rare loss‐of‐function PNPLA3 variants were not detected in early‐onset NAFLD. However, PNPLA3 rs2294918 E434K decreased PNPLA3 expression, lessening the effect of the I148M variant on the predisposition to steatosis and liver damage. This suggests that the PNPLA3 I148M variant has a codominant negative effect on triglycerides mobilization from lipid droplets, mediated by inhibition of other lipases. (Hepatology 2016;63:787–798)

315 I148M PNPLA3 POLYMORPHISM IS ASSOCIATED WITH CLINICAL FEATURES IN PATIENTS WITH HEPATOCELLULAR CARCINOMA

315 I148M PNPLA3 POLYMORPHISM IS ASSOCIATED WITH CLINICAL FEATURES IN PATIENTS WITH HEPATOCELLULAR CARCINOMA L. Valenti, B. Motta, G. Soardo, C. Bertelli, A. Sangiovanni, R. Rametta, P. Dongiovanni, M. Colombo, S. Fargion, A.L. Fracanzani. Internal Medicine, Universita’ di Milano, Internale Medicine, Universita degli Studi di Milano, Milano, University of Udine, Udine, Gastroenterology, Universita degli Studi di Milano, Milano, Italy E-mail: luca.valenti@unimi.it

The rs2294918 E434K variant modulates PNPLA3 expression and liver damage

The patatin‐like phosholipase domain‐containing 3 (PNPLA3) rs738409 polymorphism (I148M) is a major determinant of hepatic fat and predisposes to the full spectrum of liver damage in nonalcoholic fatty liver disease (NAFLD). The aim of this study was to evaluate whether additional PNPLA3 coding variants contribute to NAFLD susceptibility, first in individuals with contrasting phenotypes (with early‐onset NAFLD vs. very low aminotransferases) and then in a large validation cohort. Rare PNPLA3 variants were not detected by sequencing coding regions and intron‐exon boundaries either in 142 patients with early‐onset NAFLD nor in 100 healthy individuals with alanine aminotransferase <22/20 IU/mL. Besides rs738409 I148M, the rs2294918 G>A polymorphism (E434K sequence variant) was over‐represented in NAFLD (adjusted P = 0.01). In 1,447 subjects with and without NAFLD, the 148M‐434E (P < 0.0001), but not the 148M‐434K, haplotype (P > 0.9), was associated with histological NAFLD and steatohepatitis. Both the I148M (P = 0.0002) and E434K variants (P = 0.044) were associated with serum ALT levels, by interacting with each other, in that the 434K hampered the association with liver damage of the 148M allele (P = 0.006). The E434K variant did not affect PNPLA3 enzymatic activity, but carriers of the rs2294918 A allele (434K) displayed lower hepatic PNPLA3 messenger RNA and protein levels (P < 0.05). Conclusions: Rare loss‐of‐function PNPLA3 variants were not detected in early‐onset NAFLD. However, PNPLA3 rs2294918 E434K decreased PNPLA3 expression, lessening the effect of the I148M variant on the predisposition to steatosis and liver damage. This suggests that the PNPLA3 I148M variant has a codominant negative effect on triglycerides mobilization from lipid droplets, mediated by inhibition of other lipases. (Hepatology 2016;63:787–798)

O071 : Telomerase reverse transcriptase mutations are associated with hepatocellular carcinoma in nash

O071 TELOMERASE REVERSE TRANSCRIPTASE MUTATIONS ARE ASSOCIATED WITH HEPATOCELLULAR CARCINOMA IN NASH B. Donati, E. Vanni, P. Dongiovanni, M. Iavarone, R. Rametta, C. Rosso, A. Carnelutti, S. Petta, A.L. Fracanzani, H.L. Reeves, J.F. Dofour, L. Miele, Q. Anstee, E. Bugianesi, G. Soardo, S. Fargion, L. Valenti. Pathophysiology and Transplantation, Universita degli Studi di Milano, Milano, Medical Sciences, University of Turin, Turin, Internal Medicine, Gastroenterology, Fondazione IRCCS Ca’ Granda, Milano, Internal Medicine, University of Udine, Udine, Gastroenterology, University of Palermo, Palermo, Italy; Medicine, Freeman Hospital, Newcastle Upon Tyne, United Kingdom; Clinical Research, University of Bern, Bern, Switzerland; Internal Medicine, Catholic University, Rome, Italy; Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom; Gastroenterology, University of Turin, Turin, Italy E-mail: donatibenedetta@gmail.com

Iron overload impairs the migratory ability of a model of immature and migratory GnRH neurons

BACKGROUND Iron is essential for proper brain development in the fetal and early neonatal period. Iron represents a micronutrient for cellular metabolism and aerobic respiration, but cellular iron overload produces toxic build-up in many organs (including the brain) via free radical formation. In thalassaemic patients with pubertal failure, iron overload is the most important factor afflicting the hypothalamic-pituitary axis, leading to hypogonadotrophic hypogonadism and growth failure.