Pediatric Nonalcoholic Fatty Liver Disease: Current Thinking

A serum-induced gene signature in hepatocytes is associated with pediatric nonalcoholic fatty liver disease

OBJECTIVE

Pediatric nonalcoholic fatty liver disease (NAFLD) is a growing problem, but its underlying mechanisms are poorly understood. We used transcriptomic reporter cell assays to investigate differences in transcriptional signatures induced in hepatocyte reporter cells by the sera of children with and without NAFLD.

METHODS

We studied serum samples from 45 children with NAFLD and 28 children without NAFLD. The sera were used to induce gene expression in cultured HepaRG cells and RNA-sequencing was used to determine gene expression. Computational techniques were used to compare gene expression patterns.

RESULTS

Sera from children with NAFLD induced the expression of 195 genes that were significantly differentially expressed in hepatocytes compared to controls with obesity. NAFLD was associated with increased expression of genes promoting inflammation, collagen synthesis, and extracellular matrix remodeling. Additionally, there was lower expression of genes involved in endobiotic and xenobiotic metabolism, and downregulation of peroxisome function, oxidative phosphorylation, and xenobiotic, bile acid, and fatty acid metabolism. A 13-gene signature, including upregulation of TREM1 and MMP1 and downregulation of CYP2C9, was consistently associated with all diagnostic categories of pediatric NAFLD.

CONCLUSION

The extracellular milieu of sera from children with NAFLD induced specific gene profiles distinguishable by a hepatocyte reporter system. Circulating factors may contribute to inflammation and extracellular matrix remodeling and impair xenobiotic and endobiotic metabolism in pediatric NAFLD.

Clinical profile, referral trends, and real-world application of vibration-controlled transient elastography in children with non-alcoholic fatty liver disease in Singapore

Background and Aim

Pediatric non-alcoholic fatty liver disease (NAFLD) is a progressive disorder that is increasing in incidence globally. The study aims to describe the clinical profile and longitudinal outcome, including the utility of vibration-controlled transient elastography (VCTE), in children with NAFLD at a single tertiary liver unit in Singapore.

Methods

Retrospective review of patients aged 0-18 years referred for NAFLD from 2003 to 2020 was conducted. Diagnosis was based on persistent elevation of alanine transaminase ≥2× the upper limit of normal in at-risk patients, and/or radiologic detection of hepatic steatosis, with the exclusion of other etiologies. VCTE-derived liver stiffness measurements (LSMs) ≤7.0 , 7.1-9.0, and ≥9.1 kPa were used to differentiate normal (F0-F1), significant fibrosis (F2), and advanced fibrosis (F3-F4), respectively.

Results

The study included 210 patients (72.4% male, mean age 11.6 years). New cases increased from 1.7/1000 referrals in 2003-2008 to 12.7 and 24.5/1000 referrals in 2009-2014 and 2015-2020, respectively. Significant proportion had dyslipidemia (41.4%), impaired glucose tolerance/diabetes (IGT/DM, 26.7%), and hypertension (17.1%). Only 6.2% had resolution of NAFLD after a mean follow-up of 3.7 years. Based on VCTE (n = 65), 41.5% had normal LSM, while 26.2% and 32.3% had increased likelihood of significant and advanced fibrosis, respectively. Age ≥16 years (odds ratio [OR] 8.9), IGT/DM (OR 6.5), and aspartate transaminase >70 U/L (OR 11.0) were independent risk factors associated with increased likelihood of advanced fibrosis.

Conclusion

Incidence of pediatric NAFLD has increased dramatically in Singapore. Based on LSM estimation, pediatric NAFLD may be associated with an increased risk of developing advanced fibrosis by late adolescence.

MBR-Net: A multi-branch residual network based on ultrasound backscattered signals for characterizing pediatric hepatic steatosis

The evaluation of pediatric hepatic steatosis and early detection of fatty liver in children are of critical importance. In this paper, a deep learning model based on the convolutional neural network (CNN) of ultrasound backscattered signals, multi-branch residual network (MBR-Net), was proposed for characterizing pediatric hepatic steatosis. The MBR-Net was composed of three convolutional branches. Each branch used different sizes of convolution blocks to enhance the capability of local feature acquisition, and leveraged the residual mechanism with skip connections to guide the network to effectively capture features. A total of 393 frames of ultrasound backscattered signals collected from 131 children were included in the experiments. The hepatic steatosis index was used as the reference standard for diagnosing the steatosis grade, G0-G3. The ultrasound backscattered signals within the liver region of interests (ROIs) were normalized and augmented using a sliding gate method. The gated ROI signals were randomly divided into training, validation, and test sets with the ratio of 8:1:1. The area under the operating characteristic curve (AUC), accuracy (ACC), sensitivity (SEN), and specificity (SPE) were used as the evaluation metrics. Experimental results showed that the MBR-Net yields AUCs for diagnosing pediatric hepatic steatosis grade ≥G1, ≥G2, and ≥G3 of 0.94 (ACC: 93.65%; SEN: 89.79%; SPE: 84.48%), 0.93 (ACC: 90.48%; SEN: 87.75%; SPE: 82.65%), and 0.93 (ACC: 87.76%; SEN: 84.84%; SPE: 86.55%), respectively, which were superior to the conventional one-branch CNNs without residual mechanisms. The proposed MBR-Net can be used as a new deep learning method for ultrasound backscattered signal analysis to characterize pediatric hepatic steatosis.

The effects of Mediterranean diet on hepatic steatosis, oxidative stress, and inflammation in adolescents with non-alcoholic fatty liver disease: A randomized controlled trial

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has become the most common liver disease in children and adolescents. The optimal dietary strategy to improve hepatic stetatosis and reduce oxidative stress and inflammation in adolescents is unknown.

OBJECTIVE

This study was conducted to evaluate the effect of Mediterranean diet (MD) versus low-fat diet (LFD) on hepatic steatosis, inflammation, and oxidative stress in adolescents with obesity and NAFLD.

METHODS

Adolescents diagnosed with NAFLD between the ages of 11-18 years were randomized to either a MD or conventional LFD (control diet) for 12 weeks. Dietary status, anthropometry, body composition, and biochemical parameters were evaluated. Hepatic steatosis was determined by ultrasonography.

RESULTS

A total of 44 participants completed the study. At the end of the study, severity of hepatic steatosis, serum transaminase levels, and insulin resistance decreased significantly in both groups with no significant differences between groups except for aspartate aminotransferase (AST). The amount of decrease in AST levels in the MD group was greater than the LFD group (p < 0.05). In the MD group, serum total antioxidant capacity, paraoxanase-1, and glutathione peroxidase levels increased (p < 0.05); it did not change in the LFD group compared to baseline (p > 0.05). C-Reactive Protein (CRP) levels decreased only in the MD group (p = 0.008), interleukine-6 decreased only in the LFD group (p = 0.031).

CONCLUSION

Consumption of MD and LFD for 12 weeks in adolescents with obesity and NAFLD reduced BMI, fat mass, hepatic steatosis, and insulin resistance, improved high transaminase levels, and had positive effects on inflammation and oxidative stress. Registered under ClinicalTrials.gov Identifier no. NCT04845373.

Discriminatory capacity of obesity indicators as predictors of high liver fat in US adolescents

BACKGROUND

The aims of this study were to assess the potential of 16 anthropometric, body composition and endocrine indexes as predictors of high liver fat and determine the most appropriate cut-off points in US adolescents.

METHODS

A cross-sectional study was conducted on a population of 816 adolescents aged 12-17 years. The FibroScan^® 502V2 device was used to estimate the controlled attenuation parameter (CAP). Body fat percentage, fat mass, trunk fat percentage and trunk fat mass were measured by dual-energy X-ray absorptiometry. Anthropometric data and metabolic parameters were determined. Receiver operating characteristic curves were analysed to estimate the optimal cut-off points that best identify adolescents with high liver fat (CAP ≥90th percentile).

RESULTS

In boys, triponderal mass index (TMI) had the highest area under curve (AUC) value (0.865) and the optimal cut-off score for TMI was 17.47 kg/m³ , which had 81.32 sensitivity and 82.99 specificity. In girls, trunk fat index (TFI) had the highest AUC value (0.826) and its optimal cut-off score in screening for high liver fat was 3.76 kg/m² , which had 74.04 sensitivity and 88.03 specificity. Fat mass index (FMI) index had the second highest AUC values (0.863 in boys 0.812 in girls) in both sex; the cut-off point for the detection of high liver fat was <8.66 kg/m² for girls and <7.45 kg/m² for boys.

CONCLUSION

Assessment of TMI in boys, TFI in girls, and FMI in both sexes are low-cost and easy-to-use parameters that may be useful as early screening tools for possible high liver fat in adolescents.

Unhealthy Eating, Psychopathology, and Nonalcoholic Fatty Liver Disease in Youth Presenting for Bariatric Surgery

OBJECTIVES

Little is known about the behavioral and psychosocial correlates of pediatric nonalcoholic fatty liver disease (NAFLD). Given diet contributes to the development and persistence of NAFLD, we examined (1) the prevalence of unhealthy eating behaviors (UEB), (2) whether these varied by NAFLD or nonalcoholic steatohepatitis (NASH) presence, and explored (3) the association of psychopathology with NAFLD.

METHODS

Before metabolic and bariatric surgery (MBS), adolescents (N = 159; Mage = 16.4; MBMI = 53.7 kg/m2, 73% girls, 62.3% white) self-reported presence/absence of 10 UEB (Questionnaire on Eating and Weight Patterns-Revised, Night Eating Questionnaire, Look AHEAD). NAFLD and NASH presence was assessed by intraoperative liver biopsy. Height/weight, blood pressure, and blood specimens were obtained. A medical comorbidity index was created (prediabetes/diabetes, dyslipidemia, elevated blood pressure). Psychopathology was assessed in a subgroup completing the Youth Self-Report (N = 98).

RESULTS

Binge eating disorder symptomatology was associated with higher odds of NAFLD whereas frequent eating out was associated with lower odds of NAFLD. Among those with NAFLD frequent eating out was associated with higher odds of NASH while nocturnal eating was associated with lower odds of NASH. Separate models identified internalizing psychopathology as associated with higher odds of NAFLD after controlling for demographics, number of UEB, and medical comorbidities.

CONCLUSIONS

Results suggest potential phenotypical differences between adolescents presenting for MBS with/without NAFLD, with implications for behavioral/psychosocial targets for screening and intervention. Replication should occur in a sample with greater gender and ethnic diversity to improve generalizability. Understanding differences in the context of surgical weight loss and comorbidity resolution is indicated.

Psoas muscle area and paraspinal muscle fat in children and young adults with or without obesity and fatty liver

Background

Little is known about the muscle condition in children with obesity.

Objectives

To investigate the effect of obesity and fatty liver on muscle area and muscle fat in children and young adults.

Materials and methods

We evaluated consecutive liver fat quantification MRIs in children and young adults between June 2015 and April 2019. We obtained hepatic fat and paraspinal muscle fat at mid L2 from the fat map, psoas muscle area (PMA) at mid L3, and z-score of PMA. The patient’s age, height and weight at the time of the MRI were recorded. Body mass index (BMI) z-score was also calculated. Spearman correlation and partial correlation analyses were performed. Univariate and multivariate regression analyses were also performed using significant variables.

Results

A total of 132 patients (97 male) were included with a median age of 13.0 years (interquartile range 11–16 years). The median BMI was 23.7 kg/m² (interquartile range 21.2–27.7 kg/m²). The weight, BMI, liver fat, and z-score of PMA were all higher in male patients than they were in female patients. The amount of liver fat had no correlation with muscle fat or PMA z-score after adjusting BMI. However, the BMI z-score was positively correlated with the PMA z-score (ρ = 0.432, p<0.001) even after adjusting for liver fat. On regression analyses, the BMI z-score had linear positive relationship with PMA z-score (β = 0.289, p<0.001) and muscle fat (β = 0.218, p = 0.016).

Conclusions

Male children and young adults have greater PMA than do female children and young adults. Obesity is associated with higher PMA and paraspinal muscle fat. However, liver fat is not related with the muscle condition in children and young adults.

A clinical model to predict fibrosis on liver biopsy in paediatric subjects with nonalcoholic fatty liver disease

The incidence of nonalcoholic fatty liver disease (NAFLD) in children is rapidly increasing. Liver fibrosis is a poor prognostic feature that independently predicts cirrhosis. The time that intercedes the first medical encounter and biopsy is rate-limiting to multi-modal treatment. This study aimed to identify non-invasive parameters to predict advanced NAFLD and fibrosis. We conducted a single-center, retrospective 10-year analysis of 640 paediatric patients who underwent liver biopsy. 55 patients, age 3-21 years, had biopsy-confirmed NAFLD. We assessed primary outcomes, NAFLD activity score (NAS) and fibrosis scores, against non-invasive parameters by linear regression, by using binary cutoff values, and by a multivariate logistic regression fibrosis prediction model. NAS correlated with platelets and female sex. Fibrosis scores correlated with platelet counts, gamma glutamyl transferase (GGT), and ultrasound shear wave velocity. 25-hydroxy-vitamin D and GGT differentiated mild versus moderate-to-advanced fibrosis. Our multivariate logistical regression model-based scoring system predicted F2 or higher (parameters: BMI%, vitamin D, platelets, GGT), with sensitivity and specificity of 0.83 and 0.95 (area under the ROC curve, 0.944). We identify a clinical model to identify high-risk patients for expedited biopsy. Stratifying patients to abbreviate time-to-biopsy can attenuate delays in aggressive therapy for high-risk patients.

Higher BMI predicts liver fibrosis among obese children and adolescents with NAFLD - an interventional pilot study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) can range from simple steatosis to steatohepatitis with or without fibrosis. The predictors for liver fibrosis and the effect of nutritional intervention on hepatic fibrosis in pediatric population are not well established. We aimed to investigate the predictors for liver fibrosis and the effects of short-term nutritional intervention on steatosis and fibrosis among obese adolescents with NAFLD.

METHODS

Cross-sectional study among obese adolescents. Sociodemographic and clinical data were collected. Liver fibrosis was estimated by Shearwave elastography. All participants were recommended to consume a low carbohydrate diet and were followed biweekly. Blood tests and elastography were performed upon admission and repeated after 3 months.

RESULTS

Fifty-seven pediatric patients were recruited (35 males, mean age 13.5±2.9 years, mean body mass index [BMI] 38.8±9.7). Liver fibrosis was diagnosed in 34 (60%) subjects, which was moderate/severe (F≥2) in 24 (70%). A higher BMI Z score and moderate/severe steatosis correlated with moderate/severe fibrosis (P < 0.05). Seventeen patients completed 3 months of follow-up and displayed a decrease in BMI Z score (from BMI Z score 2.6±0.5 before intervention to 2.4±0.5 after intervention), with a significant decrease in liver fibrosis (P = 0.001).

CONCLUSION

Pediatric patients with high BMIs and severe liver steatosis are at risk for severe liver fibrosis. Nutritional intervention with minimal weight loss may improves hepatic fibrosis among the pediatric population.

TRIAL REGISTRATION

TRN NCT04561804 (9/17/2020).

Evaluation of Nonalcoholic Fatty Liver Disease in Pediatric Patients With Inflammatory Bowel Disease

Adult studies demonstrate the co-existence of nonalcoholic fatty liver disease (NAFLD) and inflammatory bowel disease (IBD) without traditional risk factors. Data in children with IBD are lacking. Here, we sought to establish the prevalence of NAFLD in a single-center pediatric IBD cohort, and identify potential risk factors. After institutional review board approval, we enrolled children with IBD who underwent routine abdominal magnetic resonance enterography. Proton density fat fraction (PDFF) was then estimated on magnetic resonance enterography. A total of 83 patients with IBD were identified and PDFF maps completed. Five (6%) were found to have PDFF >5%, meeting criteria for NAFLD. Compared to the patients with IBD without NAFLD, none of the evaluated risk factors including age, sex, diagnosis, time since diagnosis, medication, median alanine aminotransferase, and weight status were statistically significant. Our findings demonstrate the occult nature of NAFLD in pediatric IBD. The prevalence is not at variance with what is expected in general teenage populations.

Detection of pediatric hepatic steatosis through ultrasound backscattering analysis

OBJECTIVES

Hepatic steatosis has become a considerable concern in the pediatric population. The objective of this study was to evaluate the feasibility of using ultrasound Nakagami imaging to produce a parametric image for analyzing the echo amplitude distribution to assess pediatric hepatic steatosis.

METHODS

A total of 68 pediatric participants were enrolled in healthy control (n = 26) and study groups (n = 42). Raw data from ultrasound imaging were acquired for each participant analysis using AmCAD-US, a software approved by the US Food and Drug Administration for ultrasound Nakagami imaging. The Nakagami parameters were compared with the hepatic steatosis index (HSI) and the steatosis grade (G0: HSI < 30; G1: 30 ≤ HSI < 36; G2: 36 ≤ HSI < 41.6; G3: 41.6 ≤ HSI < 43; G4: HSI ≥ 43) using correlation analysis, one-way analysis of variance (ANOVA), and receiver operating characteristic (ROC) curve analysis.

RESULTS

The Nakagami parameter increased from 0.53 ± 0.13 to 0.82 ± 0.05 with increasing severity of hepatic steatosis from G0 to G4 and were significantly different between the different grades of hepatic steatosis (p < .05). The areas under the ROC curves were 0.96, 0.92, 0.85, and 0.82 for diagnosing hepatic steatosis ≥ G1, ≥ G2, ≥ G3, and ≥ G4, respectively.

CONCLUSIONS

The Nakagami parameter value quantifies changes in the echo amplitude distribution of ultrasound backscattered signals caused by fatty infiltration, providing a novel, noninvasive, and effective data analysis technique to detect pediatric hepatic steatosis.

KEY POINTS

• Ultrasound Nakagami imaging enabled quantification of the echo amplitude distribution for tissue characterization. • The Nakagami parameter increased with the increasing severity of pediatric hepatic steatosis. • The Nakagami parameter demonstrated promising diagnostic performance in evaluating pediatric hepatic steatosis.

Effects of Dietary and Lifestyle Interventions on Liver, Clinical and Metabolic Parameters in Children and Adolescents with Non-Alcoholic Fatty Liver Disease: A Systematic Review

Non-alcoholic fatty liver disease (NAFLD) affects 5.5–10.3% of children worldwide, while in obese individuals, it increases to almost 34%. Pediatric NAFLD is consistently associated with metabolic syndrome and insulin resistance. As no pharmacological agents exist for the treatment of NAFLD, lifestyle modifications remain the only therapy. However, as not all overweight/obese children have NAFLD, high-quality data, focused exclusively on NAFLD population are needed. Therefore, the present systematic review assessed the efficacy of lifestyle (diet or exercise) based on randomized controlled clinical trials (RCTs) on liver, anthropometric, glucose, and lipid parameters in children, with imaging or biopsy-proven NAFLD. In general, the results were inconclusive and therefore no specific recommendations could be drawn. In most studies, differences were derived from within group comparisons, which are known to be highly misleading. However, both low-carbohydrate and low-fat diets could benefit liver outcomes, as long as weight loss is achieved, but not necessary glucose and lipid parameters. No RCTs were found on exercise alone, as compared to no intervention on pediatric NAFLD. Concerning diet plus exercise interventions, all studies led to improvements in liver outcomes accompanied with weight loss. Resolution of NAFLD was found in considerably high percentages, while improvements were also seen in glucose but were modest in lipid parameters.

Updates in non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in childhood. There is an increase in disease prevalence and diagnoses as it is difficult to diagnose the problem. There are currently no effective medications. Management of NAFLD is a challenge for primary care clinicians and subspecialists. This paper provides guidelines for disease screening, diagnosis, management, and algorithm for subspecialty referral.

Fatty Liver Caused by Glycogen Storage Disease Type IX: A Small Series of Cases in Children

Background

The prevalence of non-alcoholic fatty liver disease (NAFLD) affecting children and adolescents has increased dramatically in recent years. This increase is most probably related to the obesity pandemic and the high consumption of fructose. However, hepatic steatosis has some rare causes (e.g., some metabolic diseases) of which clinicians should be aware, particularly (but not only) when patients are non-obese or non-overweight. Differential diagnosis is notably important when pathologies have a specific treatment, such as for glycogenosis type IX (GSD-IX).

Aims

To contribute to the knowledge on the differential diagnosis of NAFLD in paediatric age and to the clinical, biochemical, molecular, and histological characterisations of GSD-IX, a rare metabolic disorder.

Methods

We performed a retrospective study of a small series of cases (n = 3) of GSD-IX diagnosed in the past 6 years, who were currently being followed up in the Units of Gastroenterology or Metabolic Diseases of the Paediatric Division of our hospital and whose clinical presentation was NAFLD in paediatric age.

Results

Three male patients were diagnosed with NAFLD before 2 years of age, 2 with confirmed diagnosis before the age of 3 years (alanine aminotransferase [ALT], liver ultrasound, and molecular analysis) and 1 whose diagnosis was confirmed at 11 years (ALT, liver ultrasound, liver histology, and molecular analysis). None of the patients were obese or overweight, and the daily fructose consumption was unknown. The outcome was favourable in all 3 patients, with follow-up periods ranging from 2 to 6 years.

Conclusion

The decision on how far the search for secondary causes of NAFLD should go can be difficult, and GSD-IX must be on the list of possible causes.

Update on pathogenesis, diagnostics and therapy of nonalcoholic fatty liver disease in children

Nonalcoholic fatty liver disease (NAFLD) represents the most common cause of chronic liver disease. Increasing prevalence of NAFLD in children may be the cause of unfavorable metabolic implications and development of end stage liver disease. NAFLD is a “multiple-hit” disease mediated by several metabolic, environmental, genetic and microbiological mechanisms. Additionally, lipotoxicity, oxidative stress and inflammation predispose to progressive liver damage. According to current guidelines, liver biopsy is an imperfect gold standard for NAFLD diagnosis, but due to its invasive character its use is limited in children and it should be performed only in children who need exclusion of coexisting diseases. Noninvasive methods should be preferred and current research is focused on serum markers and novel imaging or elastographic techniques. Therapeutic approaches for NAFLD are currently focused on lifestyle modification, insulin resistance, dyslipidemia, oxidative stress and the gut microbiome. However, a number of clinical studies on novel therapeutic molecules are ongoing.

Childhood Fructoholism and Fructoholic Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is an emerging entity, becoming the most prevalent pediatric chronic liver disease. Its broad spectrum of histological findings, comorbidities, and complications, including cirrhosis and liver failure, can occur in childhood, emphasizing the severity of pediatric NAFLD. Current lifestyle and diet modifications have been linked to the increasing prevalence of NAFLD, including the rise of fructose consumption, a monosaccharide present in foods that contain added sugar, such as sugar‐sweetened beverages. Excessive fructose consumption is believed to cause addiction like alcohol and other drugs. As such, the new term “fructoholism” refers to the consumption of a substance (fructose) that can cause psychological and physical damage and become a major public health concern, highlighting the seriousness of the excessive consumption of fructose in the pediatric age. Hepatic fructose metabolization leads to hepatic steatosis and progression to fibrosis through mechanisms comparable to alcoholic liver disease, hence the term “fructoholic liver disease.” Conclusion: The importance of implementing reliable global strategies, such as education campaigns to promote healthy diet, increasing taxes on foods that contain added sugars, subsidies to promote accessibility to fruit and vegetables, and strict food industry regulation to reduce sugar intake in children and adolescents, cannot be overemphasized.