Excess hepatic storage of triglycerides is considered a benign condition, but nonalcoholic steatohepatitis (NASH) may progress to fibrosis and promote atherosclerosis. Carriers of the TM6SF2 E167K ...variant have fatty liver as a result of reduced secretion of very‐low‐density lipoproteins (VLDLs). As a result, they have lower circulating lipids and reduced risk of myocardial infarction. In this study, we aimed to assess whether TM6SF2 E167K affects liver damage and cardiovascular outcomes in subjects at risk of NASH. Liver damage was evaluated in 1,201 patients who underwent liver biopsy for suspected NASH; 427 were evaluated for carotid atherosclerosis. Cardiovascular outcomes were assessed in 1,819 controls from the Swedish Obese Subjects (SOS) cohort. Presence of the inherited TM6SF2 E167K variant was determined by TaqMan assays. In the liver biopsy cohort, 188 subjects (13%) were carriers of the E167K variant. They had lower serum lipid levels than noncarriers (P < 0.05), had more‐severe steatosis, necroinflammation, ballooning, and fibrosis (P < 0.05), and were more likely to have NASH (odds ratio OR: 1.84; 95% confidence interval CI: 1.23‐2.79) and advanced fibrosis (OR, 2.08; 95% CI: 1.20‐3.55), after adjustment for age, sex, body mass index, fasting hyperglycemia, and the I148M PNPLA3 risk variant. However, E167K carriers had lower risk of developing carotid plaques (OR, 0.49; 95% CI: 0.25‐0.94). In the SOS cohort, E167K carriers had higher alanine aminotransferase ALT and lower lipid levels (P < 0.05), as well as a lower incidence of cardiovascular events (hazard ratio: 0.61; 95% CI: 0.39‐0.95). Conclusions: Carriers of the TM6SF2 E167K variant are more susceptible to progressive NASH, but are protected against cardiovascular disease. Our findings suggest that reduced ability to export VLDLs is deleterious for the liver. (Hepatology 2015;61:506‐514)
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Efforts to manage non-alcoholic fatty liver disease (NAFLD) are limited by the incomplete understanding of the pathogenic mechanisms and the absence of accurate non-invasive biomarkers. The aim of ...this study was to identify novel NAFLD therapeutic targets andbiomarkers by conducting liver transcriptomic analysis in patients stratified by the presence of the
I148M genetic risk variant.
We sequenced the hepatic transcriptome of 125 obese individuals. 'Severe NAFLD' was defined as the presence of steatohepatitis, NAFLD activity score ≥4 or fibrosis stage ≥2. The circulating levels of the most upregulated transcript, interleukin-32 (IL32), were measured by ELISA.
Carriage of the
I148M variant correlated with the two major components of hepatic transcriptome variability and broadly influenced gene expression. In patients with severe NAFLD, there was an upregulation of inflammatory and lipid metabolism pathways. IL32 was the most robustly upregulated gene in the severe NAFLD group (adjusted p=1×10
), and its expression correlated with steatosis severity, both in I148M variant carriers and non-carriers. In 77 severely obese, and in a replication cohort of 160 individuals evaluated at the hepatology service, circulating IL32 levels were associated with both NAFLD and severe NAFLD independently of aminotransferases (p<0.01 for both). A linear combination of IL32-ALT-AST showed a better performance than ALT-AST alone in NAFLD diagnosis (area under the curve=0.92 vs 0.81, p=5×10
).
Hepatic IL32 is overexpressed in NAFLD, correlates with hepatic fat and liver damage, and is detectable in the circulation, where it is independently associated with the presence and severity of NAFLD.
Sparse linear algebra is fundamental to numerous areas of applied mathematics, science and engineering. In this paper, we propose an efficient data structure named AdELL+ for optimizing the SpMV ...kernel on GPUs, focusing on performance bottlenecks of sparse computation. The foundation of our work is an ELL-based adaptive format which copes with matrix irregularity using balanced warps composed using a parametrized warp-balancing heuristic. We also address the intrinsic bandwidth-limited nature of SpMV with warp granularity, blocking, delta compression and nonzero unrolling, targeting both memory footprint and memory hierarchy efficiency. Finally, we introduce a novel online auto-tuning approach that uses a quality metric to predict efficient block factors and that hides preprocessing overhead with useful SpMV computation. Our experimental results show that AdELL+ achieves comparable or better performance over other state-of-the-art SpMV sparse formats proposed in academia (BCCOO) and industry (CSR+ and CSR-Adaptive). Moreover, our auto-tuning approach makes AdELL+ viable for real-world applications.
•We propose AdELL+, an advanced GPU-based sparse matrix format.•We integrate complementary optimizations such as adaptivity and compression.•We include a warp-balancing heuristic and auto-tuning approach into a cohesive framework.•Our analysis shows that AdELL+ consistently outperforms the previous related works.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background & Aim Homozygosity for a common non-coding rs4374383 G>A polymorphism in MERTK (myeloid-epithelial-reproductive tyrosine kinase) has been associated with the protection against fibrosis ...progression in chronic hepatitis C. The main study objective was to assess whether MERTK AA genotype influences liver fibrosis, and secondarily MERTK expression in patients with non-alcoholic fatty liver disease (NAFLD). We also investigated whether MERTK is expressed in human hepatic stellate cells (HSC) and in murine models of fibrogenesis. Methods We considered 533 consecutive patients who underwent liver biopsy for suspected non-alcoholic steatohepatitis (NASH) without severe obesity from two Italian cohorts. As controls, we evaluated 158 patients with normal liver enzymes and without metabolic disturbances. MERTK rs4374383 genotype was assessed by 5′-nuclease assays. MERTK expression was analysed in mouse models of fibrosis, and the effect of the MERTK ligand GAS6 were investigated in human HSC. Results Clinically significant fibrosis (stage F2-F4) was observed in 19% of patients with MERTK AA compared to 30% in those with MERTK GG/GA (OR 0.43, CI 0.21–0.88, p = 0.02; adjusted for centre, and genetic, clinical-metabolic and histological variables). The protective rs4374383 AA genotype was associated with lower MERTK hepatic expression. MERTK was overexpressed in the liver of NAFLD patients with F2-F4 fibrosis and in in vivo models of fibrogenesis. Furthermore, exposure of cultured human HSC to the MERTK ligand GAS6, increased cell migration and induced procollagen expression. These effects were counteracted by inhibition of MERTK activity, which also resulted in apoptotic death of HSC. Conclusions The rs4374383 AA genotype, associated with lower intrahepatic expression of MERTK , is protective against F2-F4 fibrosis in patients with NAFLD. The mechanism may involve modulation of HSC activation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Steatosis has been reported to negatively influence the natural history of chronic hepatitis C (CHC), but controversy remains over its causal role due to the confounding effect of adiposity, insulin ...resistance, and diabetes. The rs738409 C>G patatin‐like phospholipase domain‐containing 3 (PNPLA3) single nucleotide polymorphism (SNP), encoding for the I148M protein variant, influences liver fat without affecting insulin resistance and body composition. The aim of this study was to evaluate the effect of the rs738409 CG genotype on liver fat and fibrosis in CHC patients. We also explored the possible effect of PNPLA3 genotype on other steatosis‐related complications, namely, treatment failure and hepatocellular carcinoma (HCC) development. To this end we considered two independent series of 325 and 494 CHC patients with available DNA and liver biopsy followed at tertiary referral centers in northern Italy. The rs738409 genotype was determined by a Taqman assay. The rs738409 GG genotype, observed in 10% of patients, was associated with steatosis independently of age, sex, body mass index (BMI), diabetes, alcohol intake, and viral genotype (odds ratio OR 1.90, 95% confidence interval CI 1.4‐2.7; P < 0.001). The association with rs738409 genotype was confirmed for severe steatosis, was independent of alanine aminotransferase (ALT) and gamma‐glutamyl transferase (GGT) values, and was observed in all viral genotypes but the 3. The rs738409 GG genotype was associated with fibrosis stage and cirrhosis (OR 1.47, 95% CI 1.2‐1.9; P = 0.002), treatment response (n = 470; OR 0.63, 95% CI 0.4‐0.8; P = 0.006), and HCC occurrence (n = 325; OR 2.16, 95% CI 1.3‐3.6; P = 0.002), independently of confounders. Conclusion: The rs738409 PNPLA3 genotype influences steatosis development in CHC and is independently associated with cirrhosis and other steatosis‐related clinical outcomes, such as lack of response to antiviral treatment and possibly HCC. (HEPATOLOGY 2011)
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
AIM:To compare iron depletion to lifestyle changes alone in patients with severe nonalcoholic fatty liver disease(NAFLD)and hyperferritinemia,a frequent feature associated with more severe liver ...damage,despite at least 6 mo of lifestyle changes.METHODS:Eligible subjects had to be 18-75 years old who underwent liver biopsy for ultrasonographically detected liver steatosis and hyperferritinemia,ferritin levels≥250 ng/mL,and NAFLD activity score>1.Iron depletion had to be achieved by removing 350 cc of blood every 10-15 d according to baseline hemoglobin values and venesection tolerance,until ferritin<30 ng/mL and/or transferrin saturation(TS)<25%.Thirty-eight patients were randomized 1:1 to phlebotomy(n=21)or lifestyle changes alone(n=17).The main outcome of the study was improvement in liver damage according to the NAFLD activity score at 2 years,secondary outcomes were improvements in liver enzymesalanine aminotransferases(ALT),aspartate aminotransferase(AST),and gamma-glutamyl-transferases(GGT).RESULTS:Phlebotomy was associated with normalization of iron parameters without adverse events.In the21 patients compliant to the study protocol,the rate of histological improvement was higher in iron depleted vs control subjects(8/12,67%vs 2/9,22%,P=0.039).There was a better improvement in steatosis grade in iron depleted vs control patients(P=0.02).In patients followed-up at two years(n=35),ALT,AST,and GGT levels were lower in iron-depleted than in control patients(P<0.05).The prevalence of subjects with improvement in histological damage or,in the absence of liver biopsy,ALT decrease≥20%(associated with histological improvement in biopsied patients)was higher in the phlebotomy than in the control arm(P=0.022).The effect of iron depletion on liver damage improvement as assessed by histology or ALT decrease≥20%was independent of baseline AST/ALT ratio and insulin resistance(P=0.0001).CONCLUSION:Iron depletion by phlebotomy is likely associated with a higher rate of improvement of histological liver damage than lifestyle changes alone in patients with NAFLD and hyperferritinemia,and with amelioration of liver enzymes.
Data on the role of hypothyroidism in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) and liver fibrosis are conflicting, although selective Thyroid Hormone Receptor (THR)-β agonists ...have been identified as potential therapy in patients with non-alcoholic steatohepatitis (NASH). Therefore, we investigated the association between hypothyroidism and NAFLD histological features potentially associated with progressive liver disease.
Between 2014 and 2016, consecutive patients with histologically proven NAFLD and frozen serum available for thyroid function tests assessment were included. NAFLD was staged according to the NAFLD Activity Score (NAS), and fibrosis according to Kleiner. NASH was defined as NAS ≥4, significant fibrosis as F2-F4 and significant steatosis as S2-S3. Thyroid function tests (TFT; TSH, FT3, FT4, rT3), TPO-Ab and Tg-Ab were also assessed.
Fifty-two patients were analyzed: median age 54 years, 58% females, LSM 7.8 kPa, 27% diabetics, 14% hypothyroid. At histology, NASH was present in 21 (40%), F2-F4 in 28 (54%) and S2-S3 in 30 (58%) patients. Rates of hypothyroidism were similar independently of the presence of NASH (p = 0.11), significant fibrosis (p = 0.21) or steatosis (p = 0.75). However, hypothyroid patients displayed a higher NAS (p = 0.02) and NASH (p = 0.06) prevalence. At multivariate analysis, TFT were not independently associated with histology.
Hypothyroidism was highly prevalent in NAFLD patients, and was associated with increased NAFLD activity, but not with fibrosis and steatosis severity. Thus, thyroid dysfunction might play a direct and/or indirect in the pathogenesis of NAFLD and NASH.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In patients with non-alcoholic fatty liver disease (NAFLD), insulin resistance (IR) associates with fibrosis progression independently of the hepatic inflammation, but the mechanisms are still ...unclear. We modeled the independent contribution of inflammation (non-alcoholic steatohepatitis: NASH) by exploiting the methionine-choline deficient (MCD) diet, and that of IR by insulin receptor (InsR) haploinsufficiency (InsR+/-) in the pathogenesis of liver fibrosis in C57BL/6 mice. We confirmed the study findings in 96 patients with NAFLD. InsR+/- enhanced hepatic fat content and impaired hepatic insulin signaling leading to Forkhead box protein O1 (FoxO1) accumulation in MCD-fed mice. Remarkably, despite reduced inflammation and hampered transdifferentiation of hepatic stellate cells (HSCs), InsR+/- promoted hepatic fibrosis accumulation, which correlated with the induction of the Lysyl Oxidase Like 2 (Loxl2), involved in matrix stabilization. Loxl2 up-regulation was not a cell autonomous property of insulin resistant HSCs, but was dependent on microparticles (MPs) released specifically by insulin resistant hepatocytes (HEPs) exposed to fatty acids. The mechanism entailed FoxO1 up-regulation, as FoxO1 silencing normalized Loxl2 expression reversing fibrosis in InsR+/- MCD-fed mice. Loxl2 up-regulation was similarly detected during IR induced by obesity, but not by lipogenic stimuli (fructose feeding). Most importantly, LOXL2 up-regulation was observed in NAFLD patients with type 2 diabetes (T2D) and LOXL2 hepatic and circulating levels correlated with histological fibrosis progression. IR favors fibrosis deposition independently of the classic 'inflammation - HSC transdifferentiation' pathway. The mechanism entails a cross-talk between enhanced lipotoxicity in insulin resistant HEPs and Loxl2 production by HSCs, which was confirmed in patients with diabetes, thereby facilitating extracellular matrix (ECM) stabilization.
A postprandial increase of translation mediated by eukaryotic Initiation Factor 6 (eIF6) occurs in the liver. Its contribution to steatosis and disease is unknown. In this study we address whether ...eIF6-driven translation contributes to disease progression. eIF6 levels increase throughout the progression from Non-Alcoholic Fatty Liver Disease (NAFLD) to hepatocellular carcinoma. Reduction of eIF6 levels protects the liver from disease progression. eIF6 depletion blunts lipid accumulation, increases fatty acid oxidation (FAO) and reduces oncogenic transformation in vitro. In addition, eIF6 depletion delays the progression from NAFLD to hepatocellular carcinoma, in vivo. Mechanistically, eIF6 depletion reduces the translation of transcription factor C/EBPβ, leading to a drop in biomarkers associated with NAFLD progression to hepatocellular carcinoma and preserves mitochondrial respiration due to the maintenance of an alternative mTORC1-eIF4F translational branch that increases the expression of transcription factor YY1. We provide proof-of-concept that in vitro pharmacological inhibition of eIF6 activity recapitulates the protective effects of eIF6 depletion. We hypothesize the existence of a targetable, evolutionarily conserved translation circuit optimized for lipid accumulation and tumor progression.
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