Paediatric nonalcoholic fatty liver disease

Gut microbiota and their metabolites in the progression of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disorder worldwide. It comprises a spectrum of conditions that range from steatosis to non-alcoholic steatohepatitis, with progression to cirrhosis and hepatocellular carcinoma. Currently, there is no FDA-approved pharmacological treatment for NAFLD. The pathogenesis of NAFLD involves genetic and environmental/host factors, including those that cause changes in intestinal microbiota and their metabolites. In this review, we discuss recent findings on the relationship(s) of microbiota signature with severity of NAFLD and the role(s) microbial metabolites in NAFLD progression. We discuss how metabolites may affect NAFLD progression and their potential to serve as biomarkers for NAFLD diagnosis or therapeutic targets for disease management.

Role of Nutrition in the Pathogenesis and Prevention of Non-alcoholic Fatty Liver Disease: Recent Updates

Non-alcoholic fatty liver disease (NAFLD) is an acquired metabolic disease characterized by triglycerides (TGs) deposition in liver induced by other factors rather than alcohol consumption. NAFLD significantly contributes to liver diseases in children and adults. NAFLD pathogenesis is associated with age, gender, race and ethnicity. Insulin resistance, hyperinsulinemia, elevated plasma free fatty acids (FFAs), fatty liver, hepatocyte injury, liver inflammation, oxidative stress, mitochondrial dysfunction, imbalanced pro-inflammatory cytokines, and fibrosis are the characteristics of NAFLD. Factors including genetic and epigenetic pathways, sedentary lifestyle, sleep, and diet composition affect NAFLD pathogenesis. In this review, we discuss the aetiology, risk factors and pathogenesis of NAFLD. Special focus is given to macro and micro nutrition as causing factors and their role in the prevention of NAFLD pathogenesis.

Predictive Role of Interleukin-18 in Liver Steatosis in Obese Children

INTRODUCTION

Interleukin-18 (IL-18) is a proinflammatory cytokine associated with metabolic syndrome (MS). Nonalcoholic fatty liver disease (NAFLD) can be recognized as a feature of MS.

MATERIAL AND METHODS

Serum IL-18 concentration was evaluated in serum of 108 obese children, determined with ELISA, and referred to degree of liver steatosis in USG or total intrahepatic lipid content assessed by magnetic resonance proton spectroscopy (¹HMRS).

RESULTS

Fatty liver was confirmed in 89 children with USG and in 72 with ¹HMRS. IL-18 concentration demonstrated significantly higher values in patients than in controls. Significant correlations between IL-18 and ALT, GGT, triglycerides, hsCRP, and the degree of liver steatosis were demonstrated. NAFLD children had significantly higher level of IL-18, ALT, GGT, HOMA-IR, waist circumference, and total lipids content in ¹HMRS than other obese children. IL-18 level was also significantly higher in obese children with advanced liver steatosis. Measurement of serum IL-18 showed ability to differentiate children with fatty liver from those without steatosis.

CONCLUSION

Elevated serum IL-18 concentration and its correlation with hepatocyte injury, systemic inflammation, and degree of liver steatosis support role in NAFLD pathomechanism. IL-18 can be considered to play a role in predicting advanced liver steatosis and fatty liver in obese children.

Laparoscopic Sleeve Gastrectomy Improves Nonalcoholic Fatty Liver Disease-Related Liver Damage in Adolescents by Reshaping Cellular Interactions and Hepatic Adipocytokine Production

OBJECTIVES

To investigate whether the modulation of local cellular cross-talks and the modification of hepatic adipocytokine expression could mechanistically explain the improvement of liver histopathology after laparoscopic sleeve gastrectomy (LSG) in adolescents with nonalcoholic fatty liver disease (NAFLD).

STUDY DESIGN

Twenty obese (body mass index of ≥35 kg/m²) adolescents who underwent LSG and with biopsy-proven NAFLD were included. At baseline (T0) and 1 year after treatment, patients underwent clinical evaluation, blood tests, and liver biopsy. Hepatic progenitor cells, hepatic stellate cells (HSCs), macrophages, and adipocytokines were evaluated by immunohistochemistry and immunofluorescence.

RESULTS

Liver biopsy samples after LSG demonstrated a significant improvement of NAFLD Activity Score and fibrosis. Immunohistochemistry indicated a significant reduction of hepatocyte cell cycle arrest, ductular reaction, activated HSC, and macrophage number after LSG compared with T0. The activation state of HSC was accompanied by modification in the expression of the autophagy marker LC3. Hepatocyte expression of adiponectin was significant higher after LSG than into T0. Moreover, LSG caused decreased resistin expression in Sox9⁺ hepatic progenitor cells compared with T0. The number of S100A9⁺ macrophages was also reduced by LSG correlating with resistin expression. Finally, serum levels of proinflammatory cytokines significantly correlated with macrophages and activated HSC numbers.

CONCLUSIONS

The histologic improvement induced by LSG is associated with the reduced activation of local cellular compartments (hepatic progenitor cells, HSCs, and macrophages), thus, strengthening the role of cellular interactions and hepatic adipocytokine production in the pathogenesis of NAFLD.

Pediatric Nonalcoholic Fatty Liver Disease: the Rise of a Lethal Disease Among Mexican American Hispanic Children

Hispanic children of Mexican origin have a high incidence of NAFLD. Susceptibility has been linked to a combination of factors including an increasing epidemic of obesity in children and adolescents, an allele substitution in the PNPLA3 gene that reduces hepatic lipid catabolism, and an altered microbiome that may increase hepatic endotoxins. The combination of NAFLD and portal vein toxins secondary to an indigenous gut microbiome appear to lead to the early occurrence of NASH, which progresses to cirrhosis and early hepatocellular carcinoma. Early detection and treatment of hepatic changes are needed. Given the success of gastric bypass in reducing body weight, modifying the gut microbiome, and improving NAFLD/NASH in adults, a trial of gastric bypass in predisposed pediatric candidates should be undertaken.

The Clinical Implications of Fatty Pancreas: A Concise Review

Fatty pancreas is a newly recognized condition which is poorly investigated until today as compared to nonalcoholic fatty liver disease. It is characterized by pancreatic fat accumulation and subsequent development of pancreatic and metabolic complications. Association of fatty pancreas have been described with type 2 diabetes mellitus, acute and chronic pancreatitis and even pancreatic carcinoma. In this review article, we provide an update on clinical implications, pathogenesis, diagnosis, treatment and outcomes.

Serum uric acid concentrations and fructose consumption are independently associated with NASH in children and adolescents

BACKGROUND & AIMS

Recent research has suggested that dietary fructose intake may increase serum uric acid (UA) concentrations. Both UA concentration and fructose consumption maybe also increase in NAFLD. It is not known whether dietary fructose consumption and UA concentration are independently associated with non-alcoholic steatohepatitis (NASH). Our aim was to investigate the factors associated with NASH in children and adolescents with proven NAFLD, and to test whether UA concentrations and fructose consumption are independently associated with NASH.

METHODS

Obese children with NAFLD were studied (n=271). NASH was diagnosed by a NAFLD activity score ⩾5 and the fatty liver inhibition of progression (FLIP) algorithm. Fructose consumption (g/day) was assessed by food frequency questionnaire, and UA (mg/dl) was measured in serum. Binary logistic regression with adjustment for covariates and potential confounders was undertaken to test factors independently associated with NASH.

RESULTS

NASH occurred in 37.6% of patients. Hyperuricaemia (UA ⩾5.9mg/dl) was present in 47% of patients with NASH compared with 29.7% of non-NASH patients (p=0.003). Both UA concentration (OR=2.488, 95% CI: 1.87-2.83, p=0.004) and fructose consumption (OR=1.612, 95% CI 1.25-1.86, p=0.001) were independently associated with NASH, after adjustment for multiple (and all) measured confounders. Fructose consumption was independently associated with hyperuricaemia (OR=2.021, 95% CI: 1.66-2.78, p=0.01). These data were confirmed using the FLIP algorithm.

CONCLUSIONS

Both dietary fructose consumption and serum UA concentrations are independently associated with NASH. Fructose consumption was the only factor independently associated with serum UA concentration.

LAY SUMMARY

Currently, it is not known whether dietary fructose consumption and uric acid (UA) concentration are linked with non-alcoholic steatohepatitis (NASH) in children and adolescents. Our aim was to test whether UA concentrations and fructose consumption are independently associated with NASH in children and adolescents with proven non-alcoholic fatty liver disease (NAFLD). We show that both dietary fructose consumption and serum UA concentrations are independently associated with NASH and fructose consumption was independently linked with high serum UA concentrations.

Features of nonalcoholic steatohepatitis in severely obese children and adolescents undergoing sleeve gastrectomy

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is an underrecognized co-morbidity of obesity. The characteristic features and severity of NAFLD in severe childhood obesity remain unknown.

OBJECTIVES

To investigate features of NAFLD in obese children and identify predictors of significant disease.

SETTING

Academic center with a standardized pathway for pediatric bariatric surgery and a dedicated multidisciplinary team.

DESIGN

This is a baseline cross-sectional analysis for a data set obtained from a prospective clinical outcome study that included severely obese children (≤14 yr of age) and adolescents (14-21 yr of age) who underwent laparoscopic sleeve gastrectomy between March 2008 and March 2015. Patients with syndromic obesity, history of alcohol intake, parenteral nutrition, liver disease, intake of medications that may affect NAFLD and weight, and insufficient tissue biopsy were excluded. Prevalence and features of nonalcoholic steatohepatitis (NASH) and clinically significant liver fibrosis in different pediatric age groups and noninvasive predictors in severe childhood obesity were evaluated.

RESULTS

The 296 patients in the study group (1:1 sex distribution) had a mean body mass index and age of 48.4±9.8 kg/m² and 14.5±3.6 years, respectively. According to histopathology assessment, 225 (76%) patients had NAFLD, of whom 118 patients (39.9% of the total cohort) had NASH. Additionally, 110 (37.2%) had clinically significant (stage 2+) fibrosis and 256 (86.5%) had portal inflammation. Those with NASH were younger than those without NASH (P = .02; prevalence of NASH in children aged≤10 yr = 64.9%) and were more likely to be male (P = .003). Of children aged≤10 years, 60% had clinically significant fibrosis compared with 32% of older patients (P = .03). High-density lipoproteins, triglycerides, glycated hemoglobin, alanine transaminase, and systolic and diastolic blood pressure levels were most predictive of fibrosis. For NASH, triglycerides, homeostatic model assessment of insulin resistance, glycated hemoglobin, alkaline phosphatase, aspartate transaminase, and alanine transaminase were most predictive.

CONCLUSIONS

In our setting, 65% of severely obese young children had NASH, and 60% had clinically significant liver fibrosis. Young age, male sex, and features of metabolic syndrome were significantly associated with NASH and liver fibrosis in severely obese pediatric patients.

LPS-induced TNF-α factor mediates pro-inflammatory and pro-fibrogenic pattern in non-alcoholic fatty liver disease

Lipopolysaccharide (LPS) is currently considered one of the major players in non-alcoholic fatty liver disease (NAFLD) pathogenesis and progression. Here, we aim to investigate the possible role of LPS-induced TNF-α factor (LITAF) in inducing a pro-inflammatory and pro-fibrogenic phenotype of non-alcoholic steatohepatitis (NASH).We found that children with NAFLD displayed, in different liver-resident cells, an increased expression of LITAF which correlated with histological traits of hepatic inflammation and fibrosis. Total and nuclear LITAF expression increased in mouse and human hepatic stellate cells (HSCs). Moreover, LPS induced LITAF-dependent transcription of IL-1β, IL-6 and TNF-α in the clonal myofibroblastic HSC LX-2 cell line, and this effect was hampered by LITAF silencing. We showed, for the first time in HSCs, that LITAF recruitment to these cytokine promoters is LPS dependent. However, preventing LITAF nuclear translocation by p38MAPK inhibitor, the expression of IL-6 and TNF-α was significantly reduced with the aid of p65NF-ĸB, while IL-1β transcription exclusively required LITAF expression/activity. Finally, IL-1β levels in plasma mirrored those in the liver and correlated with LPS levels and LITAF-positive HSCs in children with NASH.In conclusion, a more severe histological profile in paediatric NAFLD is associated with LITAF over-expression in HSCs, which in turn correlates with hepatic and circulating IL-1β levels outlining a panel of potential biomarkers of NASH-related liver damage. The in vitro study highlights the role of LITAF as a key regulator of the LPS-induced pro-inflammatory pattern in HSCs and suggests p38MAPK inhibitors as a possible therapeutic approach against hepatic inflammation in NASH.

Nonalcoholic fatty pancreas disease and Nonalcoholic fatty liver disease: more than ectopic fat

OBJECTIVE

The aim of this study was to evaluate the metabolic effects of fatty pancreas (nonalcoholic fatty pancreas disease - NAFPD) in a group of obese paediatric patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

We included 121 consecutive children with echographic evidence of hepatic steatosis. All patients underwent to abdominal ultrasound to evaluate pancreatic echogenic pattern. We divided the patients into two groups on the basis of the presence of fatty pancreas. In all patients liver function tests, lipid and gluco-insulinemic profile were evaluated. A selected subset of patients (67) underwent to liver biopsy.

RESULTS

Of these 121 patients, 58 showed NAFPD and 63 patients exhibited a normal pancreatic echogenic pattern. No differences were found in age, transaminases serum levels, lipid profile and pancreatic enzymes between the two groups. The patients with NAFPD had a significantly higher z-BMI, fasting insulin, insulin resistance (HOMA-IR) and lower ISI respect to the group without fatty pancreas. The patients with fatty pancreas showed a more advanced form of liver disease, with higher values of fibrosis, ballooning and NAS score with respect to the group without NAFPD.

CONCLUSIONS

Our study demonstrated that NAFPD is a frequent condition in obese paediatric patients affected by NAFLD. Our data suggest that pancreatic fat should not be considered an inert accumulation of fat, but as an additional factor able to affect glucose metabolism and severity of liver disease, increasing the risk of develop metabolic syndrome.

Insulin-like growth factor-I and -II levels are associated with the progression of nonalcoholic fatty liver disease in obese children

OBJECTIVE

To correlate circulating levels of insulin-like growth factor (IGF)-I, IGF-II, and IGF binding protein (IGFBP)-3 in a population of obese children with biopsy-proven nonalcoholic fatty liver disease (NAFLD) with clinical, biochemical, and histological features.

STUDY DESIGN

We conducted a cross-sectional study at the Hepatometabolic Unit of the Bambino Gesù Children's Hospital, Rome, Italy. Obese children (42 girls and 57 boys) underwent liver biopsy, anthropometry, biochemical assessment, and IGF system evaluation. Serum concentrations of IGF-I, IGF-II, and IGFBP-3 were measured. The liver biopsy features of each case were graded according to the NAFLD Activity Scoring system. The degrees of steatosis, inflammation, ballooning, and fibrosis were calculated.

RESULTS

Nonalcoholic steatohepatitis was diagnosed in 14/99 obese subjects. Stepwise regression analysis revealed that IGF-I was the major predictor of ballooning (β = -0.463; P < .0001) and NAFLD activity score (β = -0.457; P < .0001), IGF-I/IGFBP-3 ratio was the major predictor of liver inflammation (β = -0.285; P = .005), and IGF-II was the major predictor of liver fibrosis (β = 0.343; P < .005).

CONCLUSION

Circulating levels of IGF-I and IGF-II are associated with the histological stages of NAFLD and may represent novel markers of liver damage progression in obese children.

Paediatric ultrasonography of the liver, hepatobiliary tract and pancreas

In the field of paediatric radiology ultrasonography (US) is the most versatile imaging tool available. Children in general, by virtue of their body composition, are excellent candidates for US exams in whom abdominal anatomy and pathology can be visualised in great detail. The fact that during the US study a clinical history can be obtained strongly adds to the value of the US exam. This does require investment in time and expertise and ideally a paediatric radiologist performing the exam. In this review the role of ultrasonography (US) of the liver, biliary tract and pancreas in children is discussed.