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Fatty liver disease (FLD) caused by metabolic dysfunction is the leading cause of liver disease and the prevalence is rising, especially in women. Although during reproductive age women are protected against FLD, for still unknown and understudied reasons some develop rapidly progressive disease at the menopause. The patatin-like phospholipase domain-containing 3 (PNPLA3) p.I148M variant accounts for the largest fraction of inherited FLD variability. In the present study, we show that there is a specific multiplicative interaction between female sex and PNPLA3p.I148M in determining FLD in at-risk individuals (steatosis and fibrosis, P< 10−10; advanced fibrosis/hepatocellular carcinoma, P= 0.034) and in the general population (P< 10−7for alanine transaminase levels). In individuals with obesity, hepatic PNPLA3expression was higher in women than in men (P= 0.007) and in mice correlated with estrogen levels. In human hepatocytes and liver organoids, PNPLA3was induced by estrogen receptor-α (ER-α) agonists. By chromatin immunoprecipitation and luciferase assays, we identified and characterized an ER-α-binding site within a PNPLA3enhancer and demonstrated via CRISPR–Cas9 genome editing that this sequence drives PNPLA3p.I148M upregulation, leading to lipid droplet accumulation and fibrogenesis in three-dimensional multilineage spheroids with stellate cells. These data suggest that a functional interaction between ER-α and PNPLA3p.I148M variant contributes to FLD in women.

In a condition of dysfunctional visceral fat depots, as in the case of obesity, alterations in adipokine levels may be detrimental for the cardiovascular system. The proinflammatory leptin and resistin adipokines have been described as possible links between obesity and atherosclerosis. The present study was aimed at evaluating whether proprotein convertase subtilisin/kexin type 9 (PCSK9), a key regulator of low-density lipoprotein metabolism, is induced by leptin and resistin through the involvement of the inflammatory pathway of STAT3. In HepG2 cells, leptin and resistin up-regulated PCSK9gene and protein expression, as well as the phosphorylation of STAT3. Upon STAT3 silencing, leptin and resistin lost their ability to activate PCSK9. The knockdown of STAT3 did not affect the expression of leptin and resistin receptors or that of PCSK9. The analysis of the human PCSK9promoter region showed that the two adipokines raised PCSK9 promoter activity via the involvement of a sterol regulatory element motif. In healthy males, a positive association between circulating leptin and PCSK9 levels was found only when the body mass index was <25 kg/m2. In conclusion, this study identified STAT3 as one of the molecular regulators of leptin- and resistin-mediated transcriptional induction of PCSK9.

ObjectiveEfforts 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 PNPLA3I148M genetic risk variant.DesignWe 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.ResultsCarriage of the PNPLA3I148M 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=1×10−6), 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=5×10−5).ConclusionHepatic 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.

Hyperferritinemia is observed in one-third of patients with non-alcoholic fatty liver disease (NAFLD) and Metabolic Syndrome (MetS). The condition characterized by increased body iron stores associated with components of MetS has been defined as Dysmetabolic Iron Overload Syndrome (DIOS). DIOS represents the most frequent iron overload condition, since it is observed in 15% of patients with MetS and in half of those with NAFLD and its clinical presentation overlaps almost completely with that of dysmetabolic hyperferritinemia (DH). The pathogenetic mechanisms linking insulin resistance (IR), NAFLD and DIOS to iron overload are still debated. Hepcidin seems to play a role in iron accumulation in DIOS and NAFLD patients who show elevated serum hepcidin levels. The iron challenge does not restrain iron absorption despite adequate hepcidin production, suggesting that an impaired hepcidin activity rather than a deficit of hormone production underlies DIOS pathogenesis. Acquired and genetic factors are recognized to contribute to iron accumulation in NAFLD whereas additional studies are required to clearly demonstrate whether the same or different genetic factors lead to iron overload in DIOS. Finally, iron depletion by phlebotomy, together with the modification of diet and life-style habits, represents the therapeutic approach to decrease metabolic alterations and liver enzymes in NAFLD and DIOS patients. In this review, we summarized the current knowledge on the dysregulation of iron homeostasis in NAFLD and DIOS in the attempt to clarify whether they are different or more likely strictly related conditions, sharing the same pathogenic cause i.e. the MetS.

Several chronic disorders including type 2 diabetes (T2D), obesity, heart disease and cancer are preceded by a state of chronic low-grade inflammation. Biomarkers for the early assessment of chronic disorders encompass acute phase proteins (APP), cytokines and chemokines, pro-inflammatory enzymes, lipids and oxidative stress mediators. These substances enter saliva through the blood flow and, in some cases, there is a close relation between their salivary and serum concentration. Saliva can be easily collected and stored with non-invasive and cost-saving procedures, and it is emerging the concept to use it for the detection of inflammatory biomarkers. To this purpose, the present review aims to discuss the advantages and challenges of using standard and cutting-edge techniques to discover salivary biomarkers which may be used in diagnosis/therapy of several chronic diseases with inflammatory consequences with the pursuit to possibly replace conventional paths with detectable soluble mediators in saliva. Specifically, the review describes the procedures used for saliva collection, the standard approaches for the measurement of salivary biomarkers and the novel methodological strategies such as biosensors to improve the quality of care for chronically affected patients.

Dyslipidemia and altered iron metabolism are typical features of nonalcoholic fatty liver disease (NAFLD). Proprotein convertase subtilisin/kexin type 7 (PCSK7) gene variation has been associated with circulating lipids and liver damage during iron overload. The aim of this study was to examine the impact of the PCSK7rs236918 variant on NAFLD-related traits in 1,801 individuals from the Liver Biopsy Cohort (LBC), 500,000 from the UK Biobank Cohort (UKBBC), and 4,580 from the Dallas Heart Study (DHS). The minor PCSK7rs236918 C allele was associated with higher triglycerides, aminotransferases, and hepatic inflammation in the LBC (P< 0.05) and with hypercholesterolemia and liver disease in the UKBBC. In the DHS, PCSK7missense variants were associated with circulating lipids. PCSK7was expressed in hepatocytes and its hepatic expression correlated with that of lipogenic genes (P< 0.05). The rs236918 C allele was associated with upregulation of a new “intra-PCSK7” long noncoding RNA predicted to interact with the protein, higher hepatic and circulating PCSK7 protein (P< 0.01), which correlated with triglycerides (P= 0.04). In HepG2 cells, PCSK7deletion reduced lipogenesis, fat accumulation, inflammation, transforming growth factor β pathway activation, and fibrogenesis. In conclusion, PCSK7gene variation is associated with dyslipidemia and more severe liver disease in high risk individuals, likely by modulating PCSK7expression/activity.

Contrasting data have been reported on the role of irisin, a novel myokine encoded by the fibronectin type III domain-containing protein 5 (FNDC5) gene, in nonalcoholic fatty liver disease (NAFLD) pathogenesis. We tested in patients with suspected nonalcoholic steatohepatitis (NASH) the association of FNDC5 variants, hepatic expression, and circulating irisin with liver damage (F2 to F4 fibrosis as main outcome). We also investigated whether irisin modulates hepatocellular fat accumulation and stellate cell activation in experimental models.

Liver fat deposition related to systemic insulin resistance defines non-alcoholic fatty liver disease (NAFLD) which, when associated with oxidative hepatocellular damage, inflammation, and activation of fibrogenesis, i.e. non-alcoholic steatohepatitis (NASH), can progress towards cirrhosis and hepatocellular carcinoma. Due to the epidemic of obesity, NAFLD is now the most frequent liver disease and the leading cause of altered liver enzymes in Western countries. Epidemiological, familial, and twin studies provide evidence for an element of heritability of NAFLD. Genetic modifiers of disease severity and progression have been identified through genome-wide association studies. These include the Patatin-like phosholipase domain-containing 3 (PNPLA3) gene variant I148M as a major determinant of inter-individual and ethnicity-related differences in hepatic fat content independent of insulin resistance and serum lipid concentration. Association studies confirm that the I148M polymorphism is also a strong modifier of NASH and progressive hepatic injury. Furthermore, a few large multicentre case-control studies have demonstrated a role for genetic variants implicated in insulin signalling, oxidative stress, and fibrogenesis in the progression of NAFLD towards fibrosing NASH, and confirm that hepatocellular fat accumulation and insulin resistance are key operative mechanisms closely involved in the progression of liver damage. It is now important to explore the molecular mechanisms underlying these associations between gene variants and progressive liver disease, and to evaluate their impact on the response to available therapies. It is hoped that this knowledge will offer further insights into pathogenesis, suggest novel therapeutic targets, and could help guide physicians towards individualised therapy that improves clinical outcome.

Increased iron stores associated with elevated levels of the iron hormone hepcidin are a frequent feature of the metabolic syndrome. The aim of this study was to assess the effect of dietary iron supplementation on insulin resistance and the role of hepcidin in C57Bl/6 male mice fed a standard or iron-enriched diet for 16 weeks. Iron supplementation increased hepatic iron and serum hepcidin fivefold and led to a 40% increase in fasting glucose due to insulin resistance, as confirmed by the insulin tolerance test, and to threefold higher levels of triglycerides. Iron supplemented mice had lower visceral adipose tissue mass estimated by epididymal fat pad, associated with iron accumulation in adipocytes. Decreased insulin signaling, evaluated by the phospho-Akt/Akt ratio, was detected in the visceral adipose tissue of iron overloaded mice, and gene expression analysis of visceral adipose tissue showed that an iron-enriched diet up-regulated iron-responsive genes and adipokines, favoring insulin resistance, whereas lipoprotein lipase was down-regulated. This resulted in hyperresistinemia and increased visceral adipose tissue expression of suppressor of cytokine signaling-3 (Socs3), a target of resistin and hepcidin implicated in insulin resistance. Acute hepcidin administration down-regulated lipoprotein lipase and up-regulated Socs3 in visceral adipose tissue. In conclusion, we characterized a model of dysmetabolic iron overload syndrome in which an iron-enriched diet induces insulin resistance and hypertriglyceridemia and affects visceral adipose tissue metabolism by a mechanism involving hepcidin up-regulation.

The aim of the present study was to evaluate whether the lipin1 rs13412852 C>T polymorphism is associated with nonalcoholic steatohepatitis and fibrosis in pediatric Italian patients with nonalcoholic fatty liver disease (NAFLD).

The aim of the present study was to evaluate whether the lipin1 rs13412852 C>T polymorphism is associated with nonalcoholic steatohepatitis and fibrosis in pediatric Italian patients with nonalcoholic fatty liver disease (NAFLD). A total of 142 untreated, consecutive children and 115 adults with biopsy-proven NAFLD and 337 healthy controls without steatosis were studied. Liver histology was assessed by the NAFLD activity score and the rs13412852 polymorphism by a 5' nuclease Taqman assay. Homozygosity for the rs13412852 T allele was underrepresented in pediatric, but not adult, patients with NAFLD compared with healthy controls (7% vs 14%; odds ratio [OR] 0.58, 95% confidence interval [CI] 0.35–0.91), and it was associated with lower triglycerides both in pediatric patients and healthy controls (P= 0.01). Affected children carrying the rs13412852 TT genotype had a trend for a lower prevalence of nonalcoholic steatohepatitis, and significantly less severe liver damage, as indicated by NAFLD activity score severity (P= 0.026) and a lower prevalence of liver fibrosis (P= 0.012). The negative association between rs13412852 TT genotype and fibrosis was independent of Patatin-like phospholipase domain-containing-3 genotype and other clinical risk factors, including age, waist circumference, the presence of hyperglycemia, and alanine transaminase levels (OR 0.29; 95% CI 0.11–0.66), and it was confirmed at multivariate analysis in adults (OR 0.15; 95% CI 0.02–0.67). Lipin1 rs13412852 single nucleotide polymorphism is associated with the severity of liver damage and fibrosis progression in pediatric patients with histological NAFLD.

Iron overload is a risk factor for hepatocarcinoma, but the pathways involved are poorly characterized. Gene expression analysis in immortalized mouse hepatocytes exposed to iron or the iron chelator deferoxamine revealed that iron downregulated, whereas deferoxamine upregulated, mRNA levels of mouse double minute gene 2 (MDM2), the ubiquitin ligase involved in the degradation of the oncosuppressor p53. Regulation of MDM2 by iron status was observed at protein levels in mouse hepatocytes and rat liver, and was associated with specular changes in p53 expression. Iron dependent regulation of MDM2/p53 was confirmed ex-vivo in human monocytes, by manipulation of iron pool and in a genetic model of iron deficiency, leading to modulation of p53 target genes involved in the antioxidant response and apoptosis. Iron status influenced p53 ubiquitination and degradation rate, and the MDM2 inhibitor nutlin increased p53 levels in iron-depleted cells. Furthermore, nutlin enhanced the antiproliferative activity of deferoxamine in HepG2 hepatoblastoma cells. The MDM2 −309T G promoter polymorphism, determining increased MDM2 and lower p53 activity, was associated with higher risk of hepatocarcinoma in cirrhotic patients with hemochromatosis, and with HFE mutations in patients with hepatocarcinoma without hemochromatosis, suggesting an interaction between MDM2 and iron in the pathogenesis of hepatocarcinoma. In conclusion, iron status influences p53 activity and antioxidant response by modulating MDM2 expression. MDM2 inhibitors may enhance the antiproliferative activity of iron chelators.

Iron depletion improves insulin resistance in patients with nonalcoholic fatty liver disease and diabetes and also stabilizes the hypoxia-inducible factor (HIF)-1, resulting in increased glucose uptake in vitro. This study investigated the effect of iron depletion by deferoxamine on insulin signaling and glucose uptake in HepG2 hepatocytes and in rat liver. In HepG2 cells, deferoxamine stabilized HIF-1α and induced the constitutive glucose transporter Glut1 and the insulin receptor. Up-regulation of insulin receptor by deferoxamine was mimicked by the intracellular iron chelator deferasirox and the hypoxia inducer CoCl2and required the HIF-1 obligate partner ARNT/HIF-1β. Iron depletion increased insulin receptor activity, whereas iron supplementation had the opposite effect. Deferoxamine consistently increased the phosphorylation status of Akt/PKB and its targets FoxO1 and Gsk3β, which mediate the effect of insulin on gluconeogenesis and glycogen synthesis, and up-regulated genes involved in glucose uptake and utilization. Iron depletion of Sprague-Dawley rats increased HIF-1α expression, improved glucose clearance, and was associated with up-regulation of insulin receptor and Akt/PKB levels and of glucose transport in hepatic tissue. Conversely, gluconeogenic genes were not affected. In rats with fatty liver because of a high-calorie and high-fat diet, glucose clearance was increased by iron depletion and decreased by iron supplementation. Thus, iron depletion by deferoxamine up-regulates glucose uptake, and increases insulin receptor activity and signaling in hepatocytes in vitroand in vivo.

Severe iron overload usually develops in patients with hereditary hemochromatosis (HHC), but variability in the phenotypic expression of the disease has been reported. This study assessed whether tumor necrosis factor α (TNF-α) plays a role in phenotypic expression of HHC. Sixty-four patients with HHC and 172 healthy volunteers (controls) were studied. Release of TNF-α from stimulated peripheral blood monocytes was measured by enzyme-linked immunosorbent assay, and 308 and 238 TNF-α polymorphisms were detected with polymerase chain reaction and restriction fragment-length polymorphism analysis. The relation between TNF-α polymorphisms and clinical expression of HHC was evaluated. Patients with HHC released less TNF-α than controls, but the difference was significant only in homozygotes for the C282Y mutation. The prevalence of the 308 TNF-α polymorphism was similar in patients and controls, whereas the prevalence of the 238 polymorphic allele was significantly lower in patients (3% versus 16%;P= .002). A lower prevalence of cirrhosis was observed in patients with TNF-α polymorphism than in those without it (4 of 15 [27%] versus 28 of 49 [57%]), but the difference was not significant (P= .07). In nonhomozygotes for the C282Y mutation, severe liver siderosis was less prevalent in patients with the 308 polymorphism than in those without it (P= .05). Alanine aminotransferase (ALT) values were significantly lower in patients with TNF-α polymorphism (P= .006), even when patients with other hepatotoxic factors were excluded. Multivariate analysis showed that TNF-α polymorphism was independently associated with ALT values (P= .0008 and P= .045, respectively, in homozygotes and nonhomozygotes for the C282Y mutation) and siderosis in nonhomozygotes (P= .047). Thus, TNF-α appears to play a role in HHC by modulating the severity of liver damage.

Severe iron overload usually develops in patients with hereditary hemochromatosis (HHC), but variability in the phenotypic expression of the disease has been reported. This study assessed whether tumor necrosis factor α (TNF-α) plays a role in phenotypic expression of HHC. Sixty-four patients with HHC and 172 healthy volunteers (controls) were studied. Release of TNF-α from stimulated peripheral blood monocytes was measured by enzyme-linked immunosorbent assay, and 308 and 238 TNF-α polymorphisms were detected with polymerase chain reaction and restriction fragment-length polymorphism analysis. The relation between TNF-α polymorphisms and clinical expression of HHC was evaluated. Patients with HHC released less TNF-α than controls, but the difference was significant only in homozygotes for the C282Y mutation. The prevalence of the 308 TNF-α polymorphism was similar in patients and controls, whereas the prevalence of the 238 polymorphic allele was significantly lower in patients (3% versus 16%;P = .002). A lower prevalence of cirrhosis was observed in patients with TNF-α polymorphism than in those without it (4 of 15 [27%] versus 28 of 49 [57%]), but the difference was not significant (P = .07). In nonhomozygotes for the C282Y mutation, severe liver siderosis was less prevalent in patients with the 308 polymorphism than in those without it (P = .05). Alanine aminotransferase (ALT) values were significantly lower in patients with TNF-α polymorphism (P = .006), even when patients with other hepatotoxic factors were excluded. Multivariate analysis showed that TNF-α polymorphism was independently associated with ALT values (P = .0008 and P = .045, respectively, in homozygotes and nonhomozygotes for the C282Y mutation) and siderosis in nonhomozygotes (P = .047). Thus, TNF-α appears to play a role in HHC by modulating the severity of liver damage.

Increased Jagged1 in pericentral hepatocytes causes liver fibrosis in response to hepatocyte TLR4–NF-κB pathway activation in NASH.

Aberrant hepatocyte Notch activation is required for development of NASH-associated fibrosis, and Notch inhibition ameliorates obesity-induced liver disease.

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.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, 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 (p=0.0004), 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).Ferritin levels, reflecting iron stores, are independent predictors of vascular damage in NAFLD. The mechanism may involve upregulation of hepcidin levels by increased iron stores in patients not carrying HFE mutations, and iron compartmentalization into macrophages.No relevant conflicts of interest to declare.

Abstract 5098