Genetics, epigenetics and transgenerational transmission of obesity in children.

Sedentary lifestyle and consumption of high-calorie foods have caused a relentless increase of overweight and obesity prevalence at all ages. Its presently epidemic proportion is disquieting due to the tight relationship of obesity with metabolic syndrome and several other comorbidities which do call for urgent workarounds. The usual ineffectiveness of present therapies and failure of prevention campaigns triggered overtime a number of research studies which have unveiled some relevant aspects of obesity genetic and epigenetic inheritable profiles. These findings are revealing extremely precious mainly to serve as a likely extra arrow to allow the clinician's bow to achieve still hitherto unmet preventive goals. Evidence now exists that maternal obesity/overnutrition during pregnancy and lactation convincingly appears associated with several disorders in the offspring independently of the transmission of a purely genetic predisposition. Even the pre-conception direct exposure of either father or mother gametes to environmental factors can reprogram the epigenetic architecture of cells. Such phenomena lie behind the transfer of the obesity susceptibility to future generations through a mechanism of epigenetic inheritance. Moreover, a growing number of studies suggests that several environmental factors such as maternal malnutrition, hypoxia, and exposure to excess hormones and endocrine disruptors during pregnancy and the early postnatal period may play critical roles in programming childhood adipose tissue and obesity. A deeper understanding of how inherited genetics and epigenetics may generate an obesogenic environment at pediatric age might strengthen our knowledge about pathogenetic mechanisms and improve the clinical management of patients. Therefore, in this narrative review, we attempt to provide a general overview of the contribution of heritable genetic and epigenetic patterns to the obesity susceptibility in children, placing a particular emphasis on the mother-child dyad.

Profiling of cell-free DNA methylation and histone signatures in pediatric NAFLD: A pilot study.

Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease in children and adolescents, increasing the risk of its progression toward nonalcoholic steatohepatitis (NASH), cirrhosis, and cancer. There is an urgent need for noninvasive early diagnostic and prognostic tools such as epigenetic marks (epimarks), which would replace liver biopsy in the future. We used plasma samples from 67 children with biopsy-proven NAFLD, and as controls we used samples from 20 children negative for steatosis by ultrasound. All patients were genotyped for patatin-like phospholipase domain containing 3 (PNPLA3), transmembrane 6 superfamily member 2 (TM6SF2), membrane bound O-acyltransferase domain containing 7 (MBOAT7), and klotho-ß (KLB) gene variants, and data on anthropometric and biochemical parameters were collected. Furthermore, plasma cell-free DNA (cfDNA) methylation was quantified using a commercially available kit, and ImageStream(X) was used for the detection of free circulating histone complexes and variants. We found a significant enrichment of the levels of histone macroH2A1.2 in the plasma of children with NAFLD compared to controls, and a strong correlation between cfDNA methylation levels and NASH. Receiver operating characteristic curve analysis demonstrated that combination of cfDNA methylation, PNPLA3 rs738409 variant, coupled with either high-density lipoprotein cholesterol or alanine aminotransferase levels can strongly predict the progression of pediatric NAFLD to NASH with area under the curve >0.87. Conclusion: Our pilot study combined epimarks and genetic and metabolic markers for a robust risk assessment of NAFLD development and progression in children, offering a promising noninvasive tool for the consistent diagnosis and prognosis of pediatric NAFLD. Further studies are necessary to identify their pathogenic origin and function.

Combination Treatment with Hydroxytyrosol and Vitamin E Improves NAFLD-Related Fibrosis.

Non-alcoholic fatty liver disease (NAFLD)-related liver fibrosis results in the encapsulation of injured liver parenchyma by a collagenous scar mainly imputable to hepatic stellate cells' activation. Approved pharmacological treatments against NAFLD-related fibrosis are still lacking, but natural compounds such as hydroxytyrosol (HXT) and vitamin E (VitE), are emerging as promising therapeutic opportunities. In this study, the potential anti-fibrotic effect of HXT + VitE combination therapy was investigated in vitro and in vivo. In particular, tumor growth factor (TGF)-ß-activated LX-2 cells as an in vitro model, and carbon tetrachloride plus a Western diet as a mice model were employed. The effect of HXT + VitE on fibrosis was also investigated in children with biopsy-proven NAFLD. Our results demonstrated that HXT + VitE caused a reduction of proliferation, migration, contractility, and expression of pro-fibrogenic genes in TGF-ß-activated LX-2 cells. HXT + VitE treatment also antagonized TGF-ß-dependent upregulation of pro-oxidant NOX2 by interfering with nuclear translocation/activation of SMAD2/3 transcription factors. The mouse model of NAFLD-related fibrosis treated with HXT + VitE showed a marked reduction of fibrosis pattern by histology and gene expression. Accordingly, in children with NAFLD, HXT + VitE treatment caused a decrease of circulating levels of PIIINP and NOX2 that was supported over time. Our study suggests that HXT + VitE supplementation may improve NAFLD-related fibrosis.

Hydroxytyrosol Recovers SARS-CoV-2-PLpro-Dependent Impairment of Interferon Related Genes in Polarized Human Airway, Intestinal and Liver Epithelial Cells.

The SARS-CoV-2 pandemic has caused approximately 6.3 million deaths, mainly due to the acute respiratory distress syndrome or multi-organ failure that characterizes COVID-19 acute disease. Post-acute COVID-19 syndrome, also known as long-COVID, is a condition characterized by a complex of symptoms that affects 10-20% of the individuals who have recovered from the infection. Scientific and clinical evidence demonstrates that long-COVID can develop in both adults and children. It has been hypothesized that multi-organ effects of long-COVID could be associated with the persistence of virus RNA/proteins in host cells, but the real mechanism remains to be elucidated. Therefore, we sought to determine the effects of the exogenous expression of the papain-like protease (PLpro) domain of the non-structural protein (NSP3) of SARS-CoV-2 in polarized human airway (Calu-3), intestinal (Caco-2), and liver (HepG2) epithelial cells, and to evaluate the ability of the natural antioxidant hydroxytyrosol (HXT) in neutralizing these effects. Our results demonstrated that PLpro was able to induce a cascade of inflammatory genes and proteins (mainly associated with the interferon pathway) and increase the apoptotic rate and expression of several oxidative stress markers in all evaluated epithelial cells. Noteably, the treatment with 10 µM HXT reverted PL-pro-dependent effects almost completely. This study provides the first evidence that SARS-CoV-2 PLpro remaining in host cells after viral clearance may contribute to the pathogenetic mechanisms of long-COVID. These effects may be counteracted by natural antioxidants. Further clinical and experimental studies are necessary to confirm this hypothesis.

Higher Levels of Plasma Hyaluronic Acid and N-terminal Propeptide of Type III Procollagen Are Associated With Lower Kidney Function in Children With Non-alcoholic Fatty Liver Disease.

Objective: Hyaluronic acid (HA) and N-terminal propeptide of type III procollagen (PIIINP) are two non-invasive biomarkers of liver fibrosis in non-alcoholic fatty liver disease (NAFLD). We examined the relationships of plasma levels of HA and PIIINP with kidney function in children with NAFLD. Methods: Plasma HA and PIIINP levels were measured using two commercially available enzyme-linked immunosorbent assay kits in a cohort of 106 Caucasian overweight or obese children with biopsy-proven NAFLD. Glomerular filtration rate (eGFR) was estimated using the Bedside Schwartz equation. Genotyping for the patatin-like phospholipase domain-containing protein-3 (PNPLA3) rs738409 variant was performed using an allelic discrimination assay. Results: Children with fibrosis F2 had significantly higher plasma PIIINP and HA levels than those with F0 or F1 fibrosis. Liver fibrosis was positively associated with plasma HA and PIIINP, as well as with the presence of the risk allele G of PNPLA3 rs738409 variant, and negatively with eGFR. Moreover, eGFR showed significant inverse associations with HA and PIIINP levels, as well as the presence of G of PNPLA3 rs738409, and liver fibrosis stage. Notably, our multivariable regression models showed that higher plasma PIIINP (standardized beta coefficient: -0.206, P = 0.011) and HA levels (standardized beta coefficient: -0.531, P < 0.0001) were associated with lower eGFR values, even after adjustment for age, sex, systolic blood pressure, PNPLA3 rs738409 genotype, and any stage of liver fibrosis. Conclusions: Higher levels of HA and PIIINP were associated with lower eGFR values in Caucasian children with biopsy-proven NAFLD, independently of PNPLA3 rs738409 genotype and other potential confounding factors.

Variants in mitochondrial amidoxime reducing component 1 and hydroxysteroid 17-beta dehydrogenase 13 reduce severity of nonalcoholic fatty liver disease in children and suppress fibrotic pathways through distinct mechanisms.

Genome-wide association studies in adults have identified variants in hydroxysteroid 17-beta dehydrogenase 13 (HSD17B13) and mitochondrial amidoxime reducing component 1 (MTARC1) as protective against nonalcoholic fatty liver disease (NAFLD). We aimed to test their association with pediatric NAFLD liver histology and investigate their function using metabolomics. A total of 1450 children (729 with NAFLD, 399 with liver histology) were genotyped for rs72613567T>TA in HSD17B13, rs2642438G>A in MTARC1, and rs738409C>G in patatin-like phospholipase domain-containing protein 3 (PNPLA3). Genotype-histology associations were tested using ordinal regression. Untargeted hepatic proteomics and plasma lipidomics were performed in a subset of children. We found rs72613567T>TA in HSD17B13 to be associated with lower odds of NAFLD diagnosis (odds ratio, 0.7; 95% confidence interval, 0.6-0.9) and a lower grade of portal inflammation (p < 0.001). rs2642438G>A in MTARC1 was associated with a lower grade of hepatic steatosis (p = 0.02). Proteomics found reduced expression of HSD17B13 in carriers of the protective -TA allele. MTARC1 levels were unaffected by genotype. Both variants were associated with down-regulation of fibrogenic pathways. HSD17B13 perturbs plasma phosphatidylcholines and triglycerides. In silico modeling suggested p.Ala165Thr disrupts the stability and metal binding of MTARC1. Conclusion: Both HSD17B13 and MTARC1 variants are associated with less severe pediatric NAFLD. These results provide further evidence for shared genetic mechanisms between pediatric and adult NAFLD.

LncOb rs10487505 variant is associated with leptin levels in pediatric non-alcoholic fatty liver disease.

BACKGROUND: Low and high leptin levels are associated with non-alcoholic fatty liver disease (NAFLD). The LncOb rs10487505 variant has been associated with body mass index (BMI), and the C allele was reported as leptin-lowering. We evaluated the association of rs10487505 with leptin levels, liver histology, and surgery-induced weight loss in youths with NAFLD. METHODS: One-hundred five obese youths with NAFLD, of whom 19 undergoing laparoscopic sleeve gastrectomy (LSG), were analyzed for rs10487505 and leptin circulating levels. RESULTS: The G allele frequency was lower in youths with NAFLD than in controls (p = 0.049). No difference was found in anthropometrics, biochemistry and histology between G allele carriers and CC homozygotes, except for leptin levels (p = 0.016). Leptin correlated with body weight, BMI, BMI-z score, waist circumference, insulin resistance/sensitivity, and triglycerides (p ≤ 0.01). A multivariable regression model including body weight and homeostasis model assessment of insulin resistance was a good predictor of plasma leptin (R2 = 0.45), and the addition of genotype to the model increased the R2 to 0.50. Following LSG, leptin levels and body weight were more reduced in G allele carriers (p < 0.05). CONCLUSIONS: LncOb rs10487505 variant was associated with pediatric NAFLD and high leptin levels, and with weight and leptin reduction after LSG in youths. IMPACT: The interplay of environment, genetics and epigenetics is crucial inflating the risk of non-alcoholic fatty liver disease (NAFLD). Several long non-coding RNA (LncRNAs) are found associated with NAFLD pathogenesis. Here, we evaluated the impact of the genetic variant rs10487505 in LncOb which is involved in the regulation of leptin gene expression. The LncOb rs10487505 is associated with increased levels of leptin, but not with liver histology, in youths with NAFLD. The LncOb rs10487505 was also associated with the significant decrease of leptin and body weight after bariatric surgery.

Angiopoietin-2 levels correlates with disease activity in children with nonalcoholic fatty liver disease.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD), a chronic liver disease in children, ranges from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH). We investigated the role of Angiopoietin-2 (Ang-2) as a biomarker for pediatric NAFLD-related liver damage. METHODS: We assessed the plasma levels of Ang-2 and cytokeratin-18 (CK18) fragments and their association with histologic activity in 76 children with NAFLD and 28 controls. RESULTS: The mean plasma levels of Ang-2 and CK18 were higher in children with NAFLD than in age-matched controls (Ang-2 155.4 ± 72.5 vs 7.5 ± 2.3 ng/mL, p < 0.001; CK18 390.4 ± 145.6 vs 193.9 ± 30.8 IU/L, p < 0.001). Ang-2 was significantly increased (p < 0.0001) in children with NASH (N = 41) while CK18 was significantly increased (p = 0.002) in children with fibrosis (N = 47). Ang-2 levels accurately predicted NASH (AUROC 0.911; 95% CI 0.844-0.979; p < 0.0001), while CK18 predicted both NASH (AUROC 0.827; 95% CI 0.735-0.919; p < 0.0001) and fibrosis (AUROC 0.724; 95% CI 0.611-0.837; p = 0.001). Ang-2 and CK18 in combination were good predictors of NASH with a sensitivity of 71.4% and a specificity of 100%. CONCLUSIONS: In conclusion, our data suggested Ang-2 as a suitable biomarker of NASH in the pediatric population. However, our findings need external validation in other cohorts. IMPACT: Several circulating factors have been extensively studied as potential biomarkers for NASH. Angiopoietin-2 circulating levels are increased in children with NAFLD and are associated with NASH. Angiopoietin-2 levels are more efficient than CK18 levels at assessing the most severe form of disease, and the combining of these two biomarkers reached a positive predictive value of 100% for NASH.

Changes in Total Homocysteine and Glutathione Levels After Laparoscopic Sleeve Gastrectomy in Children with Metabolic-Associated Fatty Liver Disease.

PURPOSE: Paediatric obesity is a well-known risk factor for metabolic-associated fatty liver disease (MAFLD). The aim of this study was to evaluate the effects of laparoscopic sleeve gastrectomy (LSG) on the levels of total homocysteine (tHcy) and total glutathione (tGSH) plasma levels in children with MAFLD. MATERIAL AND METHODS: Twenty-four children with severe obesity who underwent LSG were included in the study. The metabolic parameters, systemic inflammatory markers, one-carbon metabolism products, ultrasound and histological improvement were evaluated at baseline (T0M) and after 12 months from LSG (T12M). RESULTS: The patients exhibited a significant amelioration of several metabolic parameters at T12M. A significant reduction of steatosis was observed at ultrasound (from 72.7% of moderate-severe grade to 0% severe steatosis), accompanied by a statistically significant improvement of ballooning, portal and lobular inflammation and fibrosis. A statistically significant decrease of tumour necrosis factor circulating levels was also observed (T0M median = 290.3, IQR = 281.0-317.0 pg/mL; T12M median = 260.4, IQR = 240.0-279.0 pg/mL; p < 0.0001). After 12 months from LSG, a significant increase of mean plasma levels of tHcy(T0M mean = 15.7 ± 4.1 µmol/L; T12M mean = 21.1 ± 9.3 µmol/L; p = 0.0146) was also observed. The increase of tHcy showed no causal link with the improvement of MAFLD-related inflammatory, metabolic and histological pattern. CONCLUSION: LSG in children with obesity induces an improvement of MAFLD-related metabolic derangement and liver damage, but also a mild hyperhomocysteinemia that should be avoided to prevent cardiovascular risk.

Focal adhesion kinase inhibitor TAE226 combined with Sorafenib slows down hepatocellular carcinoma by multiple epigenetic effects.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common and lethal malignant tumours worldwide. Sorafenib (SOR) is one of the most effective single-drug systemic therapy against advanced HCC, but the identification of novel combination regimens for a continued improvement in overall survival is a big challenge. Recent studies highlighted the crucial role of focal adhesion kinase (FAK) in HCC growth. The aim of this study was to investigate the antitumor effects of three different FAK inhibitors (FAKi), alone or in combination with SOR, using in vitro and in vivo models of HCC. METHODS: The effect of PND1186, PF431396, TAE226 on cell viability was compared to SOR. Among them TAE226, emerging as the most effective FAKi, was tested alone or in combination with SOR using 2D/3D human HCC cell line cultures and HCC xenograft murine models. The mechanisms of action were assessed by gene/protein expression and imaging approaches, combined with high-throughput methods. RESULTS: TAE226 was the more effective FAKi to be combined with SOR against HCC. Combined TAE226 and SOR treatment reduced HCC growth both in vitro and in vivo by affecting tumour-promoting gene expression and inducing epigenetic changes via dysregulation of FAK nuclear interactome. We characterized a novel nuclear functional interaction between FAK and the NuRD complex. TAE226-mediated FAK depletion and SOR-promoted MAPK down-modulation caused a decrease in the nuclear amount of HDAC1/2 and a consequent increase of the histone H3 lysine 27 acetylation, thus counteracting histone H3 lysine 27 trimethylation. CONCLUSIONS: Altogether, our findings provide the first evidence that TAE226 combined with SOR efficiently reduces HCC growth in vitro and in vivo. Also, our data highlight that deep analysis of FAK nuclear interactome may lead to the identification of new promising targets for HCC therapy.

Pediatric Non-Alcoholic Fatty Liver Disease Is Affected by Genetic Variants Involved in Lifespan/Healthspan.

OBJECTIVES: Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease in both adults and children. Along with obesity and metabolic syndrome, genetic predisposition influences the progression of NAFLD. Here, we investigated the effect of lifespan/healthspan-related single nucleotide polymorphisms (SNPs) on metabolically associated fatty liver disease in children. METHODS: We evaluated the impact of 10 SNPs involved in both human liver/metabolic diseases and healthspan (interleukin-6 [IL-6] rs1800795, antisense non coding RNA in the INK4 locus (ANRIL) rs1556516, SH2B3/ATXN2 rs7137828, FURIN rs17514846, TP53 rs1042522, APOC3 rs2542052, KL rs9536314, KL rs9527025, SIRT6 rs107251, FOXO3 rs2802292) on NAFLD-related metabolic and liver features in 177 pediatric patients with biopsy-proven NAFLD, by comparing them to 146 healthy controls. We then applied a multidimensional reduction (MDR) case-control analysis of SNP-SNP interactions, to identify the joint effect of analyzed SNPs in predicting NAFLD and associated features. RESULTS: Discrete SNPs were significantly associated with individual metabolic NAFLD features, but none of them significantly associated with NAFLD diagnosis. By testing potential synergies using the MDR approach, the best combination to diagnose NAFLD (P = 0.0011) resulted in the one encompassing IL-6 rs1800795 and ANRIL rs1556516. Consistently, the risk combinations suggested by SNP-SNP analysis strongly associated with a higher level of fasting plasma blood glucose level (P = 0.024). CONCLUSION: In conclusion, here we demonstrated a synergic interaction between IL-6 rs1800795 and ANRIL rs1556516 in the diagnosis of NAFLD, and NAFLD-associated hyperglycemia in children. Larger studies are required to confirm our findings and to elucidate mechanisms by which the genetic interaction between these two genes influences healthspan in pediatric NAFLD.

The KLB rs17618244 gene variant is associated with fibrosing MAFLD by promoting hepatic stellate cell activation.

BACKGROUND: The rs17618244 G>A ß-Klotho (KLB) variant has been associated with increased risk of ballooning and inflammation in pediatric patients with metabolic associated fatty liver disease (MAFLD), by reducing KLB expression. In hepatocytes, KLB downregulation induced fat accumulation and the expression of inflammatory and lipotoxic genes. We aimed to examine firstly the impact of the KLB rs17618244 variation on liver damage in adult patients with MAFLD and secondly its effect on hepatic stellate cells (HSCs) activation. METHODS: The impact of the KLB rs17618244 variant on histological liver damage was surveyed in a retrospective cohort of 1111 adult patients with MAFLD. Subgroup analysis was performed according to the presence of obesity (BMI>35; n = 708). Immortalized HSCs (LX-2) were transfected with the KLB wild type (LX-2_KLBwt), or with the mutant one carrying the rs17618244 (LX-2_KLBmut). FINDINGS: At ordinal regression analysis the KLB rs17618244 variant was associated with hepatic fibrosis (OR 1.23, 95% C.I.1.004-1.51; p = 0.04), but not with steatosis, inflammation and ballooning. By stratifying patients according to the presence of obesity, the KLB A allele was further associated with lobular inflammation (OR 1.32, 95% C.I.1.02-1.72; p = 0.03) and cirrhosis (OR 2.51, 95% C.I.1.23-5.05; p = 0.01) Moreover, hepatic KLB expression correlated with that of fibrogenic genes. LX-2_KLBmut cells showed reduced KLB protein levels paralleled by an induction of pro-fibrogenic genes and enhanced proliferative rate. INTERPRETATION: The KLB rs17618244 variant is associated with hepatic fibrosis, inflammation and cirrhosis mainly in obese patients with MAFLD and HSCs which carry this mutation are highly proliferative and acquire a myofibroblast-like phenotype. FUNDING: Ricerca Finalizzata Ministero della Salute GR-2019-12,370,172 (NP), Ricerca Corrente Fondazione IRCCS Cà Granda (PD and ALF), Ricerca Finalizzata Ministero della Salute RF-2013-02,358,319 (ALF), and Ricerca Corrente and 5 × 1000 Ministero della Salute (AA).

Antioxidant activity of Hydroxytyrosol and Vitamin E reduces systemic inflammation in children with paediatric NAFLD.

BACKGROUND: The rise in paediatric non-alcoholic fatty liver disease (NAFLD) is particularly alarming. We recently reported that Hydroxytyrosol (HXT) and Vitamin E (VitE) may improve oxidative stress, insulin resistance, and steatosis in children with biopsy-proven NAFLD. AIM: Here, we investigated if HXT+VitE may reduce systemic inflammation in the above-mentioned patients. METHODS: This study analysed the plasma levels of IL (interleukin)-6, IL-1ß, IL-10, tumour necrosis factor (TNF)-α, 4­hydroxy-2-nonenal (4-HNE) and 8-hydroxy-2'deoxyguanosine (8-OHdG) in children enrolled in the HXT+VitE trial (ClinicalTrials.gov, NCT02842567). RESULTS: Changes in markers of systemic inflammation were found in both placebo (Pla) and HXT+VitE. In particular, after four months, the levels of IL-1ß and TNF-α were reduced in both groups, while IL-6 decreased, and IL-10 increased significantly only in the group treated with HXT+VitE. Children treated with HXT+VitE showed a significant decrease of 4-HNE and 8-OHdG that correlated with the improvement of triglyceride levels. Noticeably, only the 8-OHdG decrease correlated with steatosis amelioration and with the increase of IL-10 levels. CONCLUSION: The treatment with HXT and VitE reduced the NAFLD-related systemic inflammation in children, mainly by an increase of IL-10 circulating levels that occurred in response to DNA damage recovery, ultimately improving steatosis and hypertriglyceridemia.

The pharmacological treatment of nonalcoholic fatty liver disease in children.

INTRODUCTION: Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in childhood/adolescence. It comprises a broad spectrum of liver disease severity ranging from simple steatosis to steatohepatitis and fibrosis. To date lifestyle modifications, diet and physical activity represent the main option for the management of pediatric NAFLD, but numerous treatments classified depending on the mechanism of action, have been introduced. In keeping with, bariatric surgery, insulin sensitizers, antioxidants, probiotic and dietary supplementations have been evaluated in pediatric clinical trials. AREAS COVERED: This review describes, after a search in PubMed/MEDLINE database, the current pediatric NAFLD non-pharmacological and pharmacological treatments and their effects on biochemical and histological features. We report not only the efficacy of the diet coupled with regular exercise but also advantages of the pharmacological treatments used in combination with lifestyle interventions in pediatric NAFLD. EXPERT OPINION: Since pharmacological and non-pharmacological interventions have demonstrated variable effects in pediatric NAFLD, it is clear that safe and specific and efficient therapeutic strategies have not yet been identified. Therefore, large and long-term clinical trials in children are needed to find a way to reverse the liver tissue damage and the NAFLD-related long-term morbidity and mortality.

Noninvasive diagnostic tools for pediatric NAFLD: where are we now?

INTRODUCTION: Nonalcoholic fatty liver disease (NAFLD) is a leading cause of liver disease in the pediatric population. It is a significant liver complication of obesity that also prominently affects children. Over the past decade, several noninvasive methods have been investigated for replacing liver biopsy to identify which children with NAFLD have nonalcoholic steatohepatitis (NASH) and fibrosis. These methods that aim to differentiate the type and extent of liver damage are based on two main different methodologies: a 'biological' approach centered on the quantification of circulating biomarkers; and a 'physical' approach established by analyzing different imaging data. AREAS COVERED: In this review, we illustrate the state of the art and recent discoveries on noninvasive methods for the diagnosis of NAFLD, NASH, and advanced fibrosis. EXPERT OPINION: Currently, noninvasive tests cannot diagnose NASH or determine the degree of fibrosis. However, several lines of evidence have suggested that if these tests are used in a complementary way with other laboratory tests and imaging they have the potential to be used to monitor progression of disease and response to therapy in pediatric NAFLD. Future scientific research will focus on combining these methods with multiple potential predictors of genetic susceptibility.

PNPLA3 gene polymorphism is associated with liver steatosis in children with Down syndrome.

BACKGROUND AND AIMS: We previously demonstrated that children with Down syndrome (DS) exhibited a greater risk of steatosis than the general pediatric population. This trend was independent of obese phenotype, thus suggesting a role of genetic predisposition. Therefore, we investigated the prevalence of non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS) in function of genetic susceptibility and adipocytokine levels in children with DS. METHODS AND RESULTS: A total of 84 Caucasian children with DS (age range 5-17 years), were included in this study. For all children, we collected data on anthropometric and biochemical parameters, and liver ultrasound (US). We also measured adipocytokines circulating levels and specific polymorphisms closed to NAFLD. We found a prevalence of 64.3% of liver steatosis at US, with a severe steatosis of about 4% in children with DS. The presence of steatosis in children with DS was associated with the presence of patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 variant, which also correlated with interleukin (IL)-6 levels. Moreover, we found that the 52.4% had a waist circumference > 90th percentile, 21.4% were hypertensive, 7.14% had hyperglycemia, 9.5% had hypertriglyceridemia, and 17.9% showed high-density lipoprotein cholesterol ≤ 40 mg/dl. Finally, the IL-6 and adiponectin levels correlated with steatosis, and several adipocytokines correlated with single MetS traits in children with DS. CONCLUSION: The present study explores for the first time potential pathomechanisms connecting pediatric NAFLD and MetS in DS. We found that the PNPLA3 variant is associated with steatosis, but not with MetS, in children with DS.

ß-Klotho gene variation is associated with liver damage in children with NAFLD.

BACKGROUND & AIM: Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease in adults and children. Along with obesity, diabetes and insulin resistance, genetic factors strongly impact on NAFLD development and progression. Dysregulated bile acid metabolism and the fibroblast growth factor 19 (FGF19) pathway play a pivotal role in NAFLD pathogenesis. However, the mechanism through which the FGF19 receptor system is associated with liver damage in NAFLD remains to be defined. METHODS: We evaluated the impact of the rs17618244 G>A ß-Klotho (KLB) variant on liver damage in 249 pediatric patients with biopsy-proven NAFLD and the association of this variant with the expression of hepatic and soluble KLB. In vitro models were established to investigate the role of the KLB mutant. RESULTS: The KLB rs17618244 variant was associated with an increased risk of ballooning and lobular inflammation. KLB plasma levels were lower in carriers of the rs17618244 minor A allele and were associated with lobular inflammation, ballooning and fibrosis. In HepG2 and Huh7 hepatoma cell lines, exposure to free fatty acids caused a severe reduction of intracellular and secreted KLB. Finally, KLB downregulation obtained by the expression of a KLB mutant in HepG2 and Huh7 cells induced intracellular lipid accumulation and upregulation of p62, ACOX1, ACSL1, IL-1ß and TNF-α gene expression. CONCLUSION: In conclusion, we showed an association between the rs17618244 KLB variant, which leads to reduced KLB expression, and the severity of NAFLD in pediatric patients. We can speculate that the KLB protein may exert a protective role against lipotoxicity and inflammation in hepatocytes. LAY SUMMARY: Genetic and environmental factors strongly impact on the pathogenesis and progression of non-alcoholic fatty liver disease (NAFLD). The FGF19/FGFR4/KLB pathway plays a pivotal role in the pathogenesis of NAFLD. The aim of the study was to investigate the impact of a genetic variant in the KLB gene on the severity of liver disease. Our data suggest that the KLB protein plays a protective role against lipotoxicity and inflammation in hepatocytes.

The Number of Liver Galectin-3 Positive Cells Is Dually Correlated with NAFLD Severity in Children.

Non-alcoholic fatty liver disease (NAFLD) is a complex disease ranging from steatosis to non-alcoholic steatohepatitis (NASH). Galectin-3 (Gal-3), which is a ß-galactoside binding protein, has been associated with liver fibrosis, but its role in NAFLD remains elusive. We investigated the expression of Gal-3 in liver resident cells and its potential association with liver damage in 40 children with biopsy-proven NAFLD. We found that several liver cells expressed Gal-3. The number of total Gal-3 positive cells decreased with the severity of disease and the cells were correlated with the presence of steatosis and the diagnosis of NASH. CD68 macrophages expressed Gal-3 but the number CD68/Gal-3 positive cells was significantly reduced in patients diagnosed with steatosis and NASH. Triple CD68/CD206/Gal-3, which represented the subpopulation of M2 macrophages, were mainly present in patients without NASH, and clearly reduced in patients with steatosis and NASH. On the contrary, the number of α-smooth muscle actin (SMA)/Gal-3 positive cells increased with the severity of fibrosis in children with NAFLD. Our data demonstrated that the number of Gal-3 positive cells was associated with tissue damage in different ways, which suggests a dual role of this protein in the pathogenesis of pediatric NAFLD, even if the role of Gal-3 deserves further studies.

Nutritional and lipidomics biomarkers of docosahexaenoic acid-based multivitamin therapy in pediatric NASH.

Two recent randomized controlled trials demonstrated improved radiographic, histological and hepatometabolic cues of non-alcoholic steatohepatitis (NASH) in pediatric patients treated with the ω-3 fatty acid docosahexaenoic acid (DHA) in combination with vitamin D (VD) or with choline (CHO) and vitamin E (VE), the DHA-VD and DHA-CHO-VE trials, respectively). In the present study we verified the nutritional compliance to these DHA-based multivitamin treatments; lipidomics biomarkers of the reported outcome on NASH indicators were also investigated. Samples were obtained from 30 biopsy-proven pediatric NASH patients of the DHA-CHO-VE trial randomized in multivitamin treatment group and placebo group (n = 15 each), and from 12 patients of the treatment group of the DHA-VD trial. All patients underwent 6-month therapy plus 6 months of follow-up. Plasma samples and clinical data were obtained at baseline and at the end of the study (12 months). Selected biomarkers included the free form of DHA and other ω-3 fatty acid arachidonic acid (AA), indices of the vitamin E status, and some hepatic metabolites of these lipids. Radiographic and histological improvements of treated patients were associated with increased concentrations of DHA, α-linolenic acid and α-tocopherol (i.e. VE), and with decreased AA that was also investigated in complex lipids by untargetd lipidomics. As a result a significantly lowered AA/DHA ratio was observed to represent the main indicator of the response to the DHA-based therapy. Furthermore, baseline levels of AA/DHA showed strong association with NAS and US improvement. A stable correction of DHA AA metabolism interaction is associated with the curative effect of this therapy and may represent a key nutritional endpoint in the clinical management of pediatric NASH.