Review article: epidemiology, pathogenesis and potential treatments of paediatric non-alcoholic fatty liver disease

Analysis of the association between dietary patterns and nonalcoholic fatty liver disease in a county in Guangxi

BACKGROUND

This study aims to investigate the relationship between different dietary patterns and non-alcoholic fatty liver disease (NAFLD).

METHODS

Residents over 30 years old in the ecological longevity cohort in Gongcheng Yao Autonomous County, Guangxi Province were the research objects selected from 2018 to 2019. Physical examination, baseline population survey, and food frequency questionnaire (FFQ) survey were conducted. Dietary patterns were analyzed by factor analysis. Influencing factors of NAFLD were analyzed by multiple logistic regression.

RESULTS

NAFLD was diagnosed in 241 of 2664 participants based on ultrasonography, and the detection rate was 9.0%. Factor analysis yielded a total of three dietary patterns, namely, traditional Chinese, Western, and cereal-potato dietary patterns. Results of multivariate logistic regression analysis showed that after adjusting for confounding factors, participants in the highest quartile of the Western dietary pattern exhibited a higher prevalence of NAFLD (OR = 2.799; 95% CI: 1.620-4.837; p < 0.05) than participants in the lowest quartile. Participants in the highest quartile of the cereal-potato pattern exhibited a decreased risk of NAFLD compared with those in the lowest quartile (OR = 0.581; 95% CI: 0.371-0.910, p < 0.05). The traditional Chinese patterns did not show any association with the risk of NAFLD.

CONCLUSIONS

The Western dietary pattern increases the risk of NAFLD, whereas the cereal-potato dietary pattern reduces the risk of NAFLD. It is important for the prevention and control of NAFLD to adhere to the cereal-potato dietary.

Development of Thyroid Hormones and Synthetic Thyromimetics in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the fastest-growing liver disease in the world. Despite targeted agents which are needed to provide permanent benefits for patients with NAFLD, no drugs have been approved to treat NASH. Thyroid hormone is an important signaling molecule to maintain normal metabolism, and in vivo and vitro studies have shown that regulation of the 3,5,3'-triiodothyronine (T3)/ thyroid hormone receptor (TR) axis is beneficial not only for metabolic symptoms but also for the improvement of NAFLD and even for the repair of liver injury. However, the non-selective regulation of T3 to TR subtypes (TRα/TRβ) could cause unacceptable side effects represented by cardiotoxicity. To avoid deleterious effects, TRβ-selective thyromimetics were developed for NASH studies in recent decades. Herein, we will review the development of thyroid hormones and synthetic thyromimetics based on TR selectivity for NAFLD, and analyze the role of TR-targeted drugs for the treatment of NAFLD in the future.

An update of the consensus statement on insulin resistance in children 2010

In our modern society, where highly palatable and calorie-rich foods are readily available, and sedentary lifestyle is common among children and adolescents, we face the pandemic of obesity, nonalcoholic fatty liver disease, hypertension, atherosclerosis, and T2D. Insulin resistance (IR) is known to be the main underlying mechanism of all these associated health consequences; therefore, the early detection of IR is fundamental for preventing them.A Consensus Statement, internationally supported by all the major scientific societies in pediatric endocrinology, was published in 2010, providing all the most recent reliable evidence to identify the definition of IR in children, its measurement, its risk factors, and the effective strategies to prevent and treat it. However, the 2010 Consensus concluded that further research was necessary to assess some of the discussed points, in particular the best way to measure insulin sensitivity, standardization of insulin measurements, identification of strong surrogate biomarkers of IR, and the effective role of lifestyle intervention and medications in the prevention and treatment of IR.The aim of this review is to update each point of the consensus with the most recent available studies, with the goal of giving a picture of the current state of the scientific literature regarding IR in children, with a particular regard for issues that are not yet fully clarified.

Metabolomics Defines Complex Patterns of Dyslipidaemia in Juvenile-SLE Patients Associated with Inflammation and Potential Cardiovascular Disease Risk

Cardiovascular disease (CVD) is a leading cause of mortality in patients with juvenile-onset systemic lupus erythematosus (JSLE) associated with atherosclerosis. The interplay between dyslipidaemia and inflammation—mechanisms that drive atherosclerosis—were investigated retrospectively in adolescent JSLE patients using lipoprotein-based serum metabolomics in patients with active and inactive disease, compared to healthy controls (HCs). Data was analysed using machine learning, logistic regression, and linear regression. Dyslipidaemia in JSLE patients was characterised by lower levels of small atheroprotective high-density lipoprotein subsets compared to HCs. These changes were exacerbated by active disease and additionally associated with significantly higher atherogenic very-low-density lipoproteins (VLDL) compared to patients with low disease activity. Atherogenic lipoprotein subset expression correlated positively with clinical and serological markers of JSLE disease activity/inflammation and was associated with disturbed liver function, and elevated expression of T-cell and B-cell lipid rafts (cell signalling platforms mediating immune cell activation). Finally, exposing VLDL/LDL from patients with active disease to HC lymphocytes induced a significant increase in lymphocyte lipid raft activation compared to VLDL/LDL from inactive patients. Thus, metabolomic analysis identified complex patterns of atherogenic dyslipidaemia in JSLE patients associated with inflammation. This could inform lipid-targeted therapies in JSLE to improve cardiovascular outcomes.

Protective effect of fenofibrate against high-fat-high-fructose diet induced non-obese NAFLD in rats

The present study evaluated the protective effects of fenofibrate on liver function, oxidant-antioxidant balance, and insulin resistance (IR) in rats fed high-fat-high-fructose diet (HFFD). Twenty-four male Sprague-Dawley rats (110-130 gm) were allocated into four equal groups (n = 6). Rats in group I were fed a normal diet for 4 weeks. Rats in group II were fed a normal diet with fenofibrate at 50 mg/kg/day orally for four weeks. Rats in group III were fed a normal diet mixed with 25% palm oil and given 60% fructose solution orally for 4 weeks. Rats in group IV were fed a normal diet mixed with 25% palm oil, 60% oral fructose solution, and fenofibrate at 50 mg/kg/day orally for four weeks. After experimental induction, serum and liver tissue samples were collected to determine lipid profiles, glycemic status, antioxidant status, oxidative and stress markers, and histopathology of liver tissues. The results of the present study revealed that fenofibrate prevents the occurrence of fatty liver, enhancing glycemic status, decreasing oxidative stress, and improving antioxidant status. It can be concluded that fenofibrate has a lipotropic and antidiabetic role.

Metabolic syndrome in children

Despite plenty of currently available information on metabolic syndrome (MetS) in children and adolescents, there are still uncertainties regarding definition, prevention, management and treatment of MetS in children. The first approach to MetS in children consists of lifestyle interventions (nutritional education, physical activity). These recommendations are often difficult to achieve, especially for adolescents, therefore, there is usually a lack of successful outcomes. A pharmacological intervention in obese children may be needed in some cases, with the aim to improve the effects of these primary prevention interventions. Metformin seems to be safe and presents evident positive effects on insulin sensitivity, but long-term and consistent data are still missing to establish its role in the pediatric population and the possible effectiveness of other emergent treatments such as glucagon-like peptide-1 analogues, dipeptidylpeptidase-4 inhibitors, dual inhibitors of SGLT1 and SGLT2 and weight loss drugs. Bariatric surgery might be helpful in selected cases. The aim of this review is to present the most recent available treatments for the main components of metabolic syndrome, with a focus on insulin resistance. A short mention of management of congenital forms of insulin resistance will be included too.

Analysis of correlation between liver fat fraction and AST and ALT levels in overweight and obese children by using new magnetic resonance imaging technique

BACKGROUND/AIMS

Proton density fat fraction (PDFF) magnetic resonance (MR) imaging can be a useful technique for volumetric measurements of liver fat. The purpose of our study was to evaluate the correlation between liver fat fraction (LFF) and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in children who are overweight and obese.

MATERIALS AND METHODS

Overall, 25 children, aged 9-17 years, were included. Patients with a body mass index (BMI) z-score between 85-95th percentile (12 of 25 patients) were assigned to the overweight group, and those with BMI z-score above 95th percentile (13 of 25 patients) were assigned to the obese group. The control group comprised 12 healthy children with BMI z-score below 85th percentile. Liver fat fraction measurements were performed on 3D volume measurement workstation by using PDFF magnetic resonance (MR) images. Spearman's correlation coefficients between liver fat fraction and AST and ALT levels were evaluated individually for overweight, obese, and control groups. Receiver operator characteristics (ROC) analysis was also performed.

RESULTS

In the overweight and obese groups, the liver proton density fat fraction and AST levels had a strong correlation (r=0.716, p<0.001). In addition, the LFF and ALT levels demonstrated a strong correlation (r=0.878, p<0.001). ROC analysis ascertained an optimal liver fat fraction threshold of 114 for predicting AST level (sensitivity=75%, specificity=89%). ROC analysis ascertained an optimal LFF threshold of 114 for predicting ALT level (sensitivity=80%, specificity=90%).

CONCLUSION

Our results indicate a strong correlation between LFF values and AST and ALT levels in children who are overweight and obese.

Serum miR-379 expression is related to the development and progression of hypercholesterolemia in non-alcoholic fatty liver disease

Introduction

Non-alcoholic fatty liver disease (NAFLD) has a wide spectrum, eventually leading to cirrhosis and hepatic carcinogenesis. We previously reported that a series of microRNAs (miRNAs) mapped in the 14q32.2 maternally imprinted gene region (Dlk1-Dio3 mat) are related to NAFLD development and progression in a mouse model. We examined the suitability of miR-379, a circulating Dlk1-Dio3 mat miRNA, as a human NAFLD biomarker.

Methods

Eighty NAFLD patients were recruited for this study. miR-379 was selected from the putative Dlk1-Dio3 mat miRNA cluster because it exhibited the greatest expression difference between NAFLD and non-alcoholic steatohepatitis in our preliminary study. Real-time PCR was used to examine the expression levels of miR-379 and miR-16 as an internal control. One patient was excluded due to low RT-PCR signal.

Results

Compared to normal controls, serum miR-379 expression was significantly up-regulated in NAFLD patients. Receiver operating characteristic curve analysis suggested that miR-379 is a suitable marker for discriminating NAFLD patients from controls, with an area under the curve value of 0.72. Serum miR-379 exhibited positive correlations with alkaline phosphatase, total cholesterol, low-density-lipoprotein cholesterol and non-high-density-lipoprotein cholesterol levels in patients with early stage NAFLD (Brunt fibrosis stage 0 to 1). The correlation between serum miR-379 and cholesterol levels was lost in early stage NAFLD patients treated with statins. Software-based predictions indicated that various energy metabolism–related genes, including insulin-like growth factor-1 (IGF-1) and IGF-1 receptor, are potential targets of miR-379.

Conclusions

Serum miR-379 exhibits high potential as a biomarker for NAFLD. miR-379 appears to increase cholesterol lipotoxicity, leading to the development and progression of NAFLD, via interference with the expression of target genes, including those related to the IGF-1 signaling pathway. Our results could facilitate future research into the pathogenesis, diagnosis, and treatment of NAFLD.

Non-alcoholic fatty liver infiltration in children: an underdiagnosed evolving disease

Non-alcoholic fatty liver disease (NAFLD) constitutes the most common liver disease, one that is still underdiagnosed in pediatric populations (as well as in the general population), this due to the progressive increase in childhood obesity observed both in developed and developing countries during the last few decades. The pathophysiology of the disease has not been thoroughly clarified yet. The condition displays common pathways in adults and children; however, there are age-related differences. Unlike adults, children with NAFLD require extensive laboratory analysis, because underlying pathologies other than obesity may contribute to the evolution of the disease. Despite the presence of several serum markers and imaging techniques that contribute to NAFLD diagnosis, liver biopsy remains the gold standard diagnostic procedure. Early intervention and obesity prevention are mandatory, as NAFLD is reversible at an early stage. If left undiagnosed and untreated, NAFLD can progress to steatohepatitis (NASH) and subsequent liver failure, a potentially lethal complication. Of note, there are no treatment options when advanced liver fibrosis occurs. This review summarizes literature data on NAFLD in childhood indicating that this is an evolving disease and a significant component of the metabolic syndrome. Pediatricians should be aware of this entity, screening children at high risk and providing appropriate early management, in collaboration with pediatric subspecialists.

Pediatric NAFLD: an overview and recent developments in diagnostics and treatment

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in children and adults in industrialized countries. Besides liver-related morbidity, NAFLD is also associated with an increased risk of cardiovascular disease, type 2 diabetes and mortality at adult age. However, despite the high prevalence and serious complications, diagnosing and staging of disease remains complicated due to a lack of accurate screening tools and non-invasive methods to detect fibrosis. Areas covered: Recent insights in epidemiology, pathogenesis, diagnostic evaluation and treatment options in pediatric NAFLD are being reviewed, with a particular focus on new developments in diagnostic tools. Expert opinion: Due to their long life span, children with NAFLD are particularly at risk of complications in their lifetime. Therefore, an effective screening strategy for children to identify those with NAFLD at risk of complications is urgently needed. This is further underscored by new pharmacological therapies that are expected to become available in the next 5 years. Momentarily no accurate non-invasive method for diagnosing pediatric NAFLD is available. New promising biomarkers and imaging tools could hopefully provide better screening tools and could contribute to the development of a successful management plan to identify children with NAFLD.

The Liver Fat Fraction and Abdominal Subcutaneous and Visceral Fat Volume Distribution in Normal-Weight, Overweight, and Obese Children Using a New Magnetic Resonance Imaging Technique

OBJECTIVES

The purpose of this study was to evaluate liver fat fraction and subcutaneous and visceral fat volumes using new magnetic resonance imaging in normal-weight, overweight, and obese children.

METHODS

Patients at below the 85th percentile of body mass index (BMI) z score (5/25 patients) were assigned to the normal-weight group; patients between 85th and 95th percentile of BMI z score (9/25 patients) were assigned to the overweight group, and patients above the 95th percentile of BMI z score (11/25 patients) were assigned to the obese group. Liver fat fraction and subcutaneous and visceral fat volumes were measured on 3-dimensional volume measurement workstation.

RESULTS

Liver fat fraction and subcutaneous fat volume had weak correlation (r = 0.18, P = 0.411). Liver fat fraction and visceral fat volume revealed weak correlation (r = 0.25, P = 0.672); visceral and subcutaneous fat volume demonstrated strong correlation (r = 0.67, P = 0.047).

CONCLUSIONS

There is strong correlation between subcutaneous fat volume and visceral fat volume in overweight and obese children.

Independent and combined effects of dietary iron composition and selected risk factors on the risk of NAFLD in a Chinese population

Iron is an essential mineral required for most forms of life. However, very little is known in relation to the different forms of dietary iron on the development of NAFLD. The aims of this study were to investigate the effects of iron intake from different food types on risk of NAFLD and whether this effect may be modified by other factors. We conducted a hospital-based case–control study including 1,273 NAFLD cases and 1,273 gender and age-matched controls. We conducted in-person interviews while participants completed a questionnaire on food habits. We assessed animal- and plant-derived intake of iron and fat. We observed that animal-derived iron intake (>4.16 mg/day) was positively associated with augmented NAFLD risk in a Chinese population (OR_adjusted = 1.66 in the highest quartile compared with the lowest, 95% confidence interval [CI] = 1.01–2.73). In contrast, a high consumption of iron (>16.87 mg/day) from plant-based foods was associated with a decreased NAFLD risk (ORadjusted = 0.61 in the highest quartile compared with the lowest; 95% CI = 0.40–0.935). In addition, high intake of fat or being overweight may exacerbate this effect. Reduced consumption of iron and fat from animal sources could reduce NAFLD risk, as would weight loss.

Dietary determinants of hepatic fat content and insulin resistance in overweight/obese children: a cross-sectional analysis of the Prevention of Diabetes in Kids (PREDIKID) study

Paediatric non-alcoholic fatty liver disease has increased in parallel with childhood obesity. Dietary habits, particularly products rich in sugars, may influence both hepatic fat and insulin resistance (homeostatic model assessment for insulin resistance (HOMA-IR)). The aim of the study was to examine the association of the consumption of foods and food components, dairy desserts and substitutes (DDS), sugar-sweetened beverages (SSB), as well as total and added sugars, with hepatic fat and HOMA-IR. Dietary intake (two non-consecutive 24 h-recalls), hepatic fat (MRI) and HOMA-IR were assessed in 110 overweight/obese children (10·6 (sd 1·1) years old). Linear regression analyses were used to examine the association of dietary intake with hepatic fat and HOMA-IR adjusted for potential confounders (sex, age, energy intake, maternal educational level, total and abdominal adiposity and sugar intake). The results showed that there was a negative association between cereal intake and hepatic fat (β=-0·197, P&lt;0·05). In contrast, both SSB consumption (β=0·217; P=0·028) and sugar in SSB (β=0·210, P=0·035), but not DDS or sugar in DDS or other dietary components, were positively associated with hepatic fat regardless of potential confounders including total sugar intake. In conclusion, cereal intake might decrease hepatic fat, whereas SSB consumption and its sugar content may increase the likelihood of having hepatic steatosis. Although these observations need to be confirmed using experimental evidence, these results suggest that healthy lifestyle intervention programs are needed to improve dietary habits as well as to increase the awareness of the detrimental effects of SSB consumption early in life.

Acoustic radiation force impulse imaging for detection of liver fibrosis in overweight and obese children

Background Acoustic radiation force impulse (ARFI) is a non-invasive alternative to a liver biopsy for the evaluation of liver fibrosis (LF). Purpose To investigate the potential usefulness of acoustic radiation force impulse ARFI for detecting LF in overweight and obese children Material and Methods A cross-sectional study was conducted in 148 schoolchildren. A diagnosis of non-alcoholic fatty liver disease (NAFLD) and LF was based on ultrasound (US) and ARFI shear wave velocity (SWV). Results The laboratory parameters were normal in all the children. NAFLD was observed in 50 children (33.8%). The median SWV was 1.18 ± 0.28 m/s. Differences between ARFI categories and hepatic steatosis grades were observed (χ2 = 43.38, P = 0.0005). No fibrosis or insignificant fibrosis (SWV ≤ 1.60 m/s) was detected in 137 children (92.5%), and significant fibrosis (SWV > 1.60 m/s) in 11 children (7.5%), nine of whom had normal US or mild steatosis. Conclusion The present study is the first to evaluate the utility of the ARFI technique for detecting LF in overweight and obese children. The results of the study suggest that children with normal laboratory parameters such as normal liver ultrasound or mild steatosis may present with significant LF.

The effect of diet or exercise on ectopic adiposity in children and adolescents with obesity: a systematic review and meta-analysis

OBJECTIVE

Ectopic fat depostion in youth with obesity is associated with an increased cardiovascular disease risk. The aim of this meta-analysis was to summarize the evidence for the use of diet and/or exercise on ectopic adiposity in this population.

METHODS

A systematic literature search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement. Clinical trials that assessed ectopic fat deposition and included study arms with diet and/or exercise were searched in PubMed, PEDro and the Cochrane database.

RESULTS

Hepatic fat content and intramyocellular lipid content were described in nine studies and three studies, respectively. Most studies included teenagers, and study duration ranged between 3 and 12 months without follow-up. Using random-effects weights, the standardized mean difference of the change in hepatic adiposity (totalling 320 subjects) was -0.54 Hedges' g (95% confidence interval: -0.69 to -0.38 with p < 0.0001). By re-expressing this effect size, it is seen that diet and/or exercise results in an absolute reduction of intrahepatic lipid with 2%, which accords with a relative reduction up to 70%. Although there were significant ameliorations of insulin sensitivity, no significant changes in intramyocellular lipid were observed.

CONCLUSIONS

This meta-analysis showed that diet and/or exercise is effective to reduce hepatic adiposity in youth with obesity.

Steatosis induced CCL5 contributes to early-stage liver fibrosis in nonalcoholic fatty liver disease progress

The rapidly increasing prevalence of nonalcoholic fatty liver disease (NAFLD) has become one of the major public health threats in China and worldwide. However, during the development of NAFLD, the key mechanism underlying the progression of related fibrosis remains unclear, which greatly impedes the development of optimal NAFLD therapy. In the current study, we were endeavored to characterize a proinflammatory cytokine, CCL5, as a major contributor for fibrosis in NAFLD. The results showed that CCL5 was highly expressed in fatty liver and NASH patients. In NAFLD rats induced by 8-week-HFD, CCL5 and its receptor, CCR5, were significantly up-regulated and liver fibrosis exclusively occurred in this group. In addition, we showed that hepatocytes are the major source contributing to this CCL5 elevation. Interestingly, a CCL5 inhibitor Met-CCL5, significantly decreased liver fibrosis but not hepatic steatosis. Using a cell model of hepatic steatosis, we found that the conditioned medium of lipid-overloaded hepatocytes (Fa2N-4 cells) which produced excessive CCL5 stimulated the profibrotic activities of hepatic stellate cells (LX-2) as manifested by increased migration rate, proliferation and collagen production of LX-2 cells. CCL5 knockdown in Fa2N-4 cells, Met-CCL5 or CCR5 antibody treatment on LX-2 cells all significantly inhibited the conditioned medium of FFA-treated Fa2N-4 cells to exert stimulatory effects on LX-2 cells. Consistently, the conditioned medium of Fa2N-4 cells with CCL5 over-expression significantly enhanced migration rate, cell proliferation and collagen production of LX-2 cells. All these results support that CCL5 produced by steatotic hepatocytes plays an essential role in fibrotic signaling machinery of NAFLD. In addition, we were able to identify C/EBP-β as the up-stream regulator of CCL5 gene transcription in hepatocytes treated with free fatty acid (FFA). Our data strongly supported that CCL5 plays a pivotal regulatory role in hepatic fibrosis during NAFLD, which constitutes a novel and exciting observation that may call for potential future development of specific CCL5-targeted NAFLD therapy.

Imaging patterns of fatty liver in pediatric patients

Fatty liver can present as focal, diffuse, heterogeneous, and multinodular forms. Being familiar with various patterns of steatosis can enable correct diagnosis. In patients with equivocal findings on ultrasonography, magnetic resonance imaging can be used as a problem solving tool. New techniques are promising for diagnosis and follow-up. We review imaging patterns of steatosis and new quantitative methods such as proton density fat fraction and magnetic resonance elastography for diagnosis of nonalcoholic fatty liver disease in children.

In Children With Nonalcoholic Fatty Liver Disease, Cysteamine Bitartrate Delayed Release Improves Liver Enzymes but Does Not Reduce Disease Activity Scores

BACKGROUND & AIMS

No treatment for nonalcoholic fatty liver disease (NAFLD) has been approved by regulatory agencies. We performed a randomized controlled trial to determine whether 52 weeks of cysteamine bitartrate delayed release (CBDR) reduces the severity of liver disease in children with NAFLD.

METHODS

We performed a double-masked trial of 169 children with NAFLD activity scores of 4 or higher at 10 centers. From June 2012 to January 2014, the patients were assigned randomly to receive CBDR or placebo twice daily (300 mg for patients weighing ≤65 kg, 375 mg for patients weighing >65 to 80 kg, and 450 mg for patients weighing >80 kg) for 52 weeks. The primary outcome from the intention-to-treat analysis was improvement in liver histology over 52 weeks, defined as a decrease in the NAFLD activity score of 2 points or more without worsening fibrosis; patients without biopsy specimens from week 52 (17 in the CBDR group and 6 in the placebo group) were considered nonresponders. We calculated the relative risks (RR) of improvement using a stratified Cochran-Mantel-Haenszel analysis.

RESULTS

There was no significant difference between groups in the primary outcome (28% of children in the CBDR group vs 22% in the placebo group; RR, 1.3; 95% confidence interval [CI], 0.8-2.1; P = .34). However, children receiving CBDR had significant changes in prespecified secondary outcomes: reduced mean levels of alanine aminotransferase (reduction, 53 ± 88 U/L vs 8 ± 77 U/L in the placebo group; P = .02) and aspartate aminotransferase (reduction, 31 ± 52 vs 4 ± 36 U/L in the placebo group; P = .008), and a larger proportion had reduced lobular inflammation (36% in the CBDR group vs 21% in the placebo group; RR, 1.8; 95% CI, 1.1-2.9; P = .03). In a post hoc analysis of children weighing 65 kg or less, those taking CBDR had a 4-fold better chance of histologic improvement (observed in 50% of children in the CBDR group vs 13% in the placebo group; RR, 4.0; 95% CI, 1.3-12.3; P = .005).

CONCLUSIONS

In a randomized trial, we found that 1 year of CBDR did not reduce overall histologic markers of NAFLD compared with placebo in children. Children receiving CBDR, however, had significant reductions in serum aminotransferase levels and lobular inflammation. ClinicalTrials.gov no: NCT01529268.

Epidemiology and natural history of non-alcoholic fatty liver disease

Non-alcoholic steatohepatitis (NASH) is part of the spectrum of non-alcoholic fatty liver disease (NAFLD) that leads to progressive liver disease and presents a growing challenge to public health. Because of the increased prevalence of metabolic syndrome and obesity, NAFLD and NASH have expanded to a substantial extent. In NASH patients, advanced fibrosis is the major predictor of morbidity and liver-related mortality, and an accurate diagnosis of NASH is mandatory. Although there is currently no validated test of serum biomarkers available to diagnose NASH, and histologic evaluation with a liver biopsy remains the gold standard, screening for fibrosis is recommended in patients with suspicion of NASH. Clinical prediction models and serum biomarkers for advanced fibrosis have relatively good negative predictive value and can be useful for screening. Also, transient elastography is increasingly available to estimate fibrosis in NASH. Therefore, due to the lack of a reliable and accepted non-invasive diagnostic modality, screening for NASH in the general population is not currently recommended. Better understanding of the natural history of NASH is needed to evaluate the utility and cost-effectiveness of screening.

A Guide to Non-Alcoholic Fatty Liver Disease in Childhood and Adolescence

Non-Alcoholic Fatty Liver Disease (NAFLD) is now the most prevalent form of chronic liver disease, affecting 10%–20% of the general paediatric population. Within the next 10 years it is expected to become the leading cause of liver pathology, liver failure and indication for liver transplantation in childhood and adolescence in the Western world. While our understanding of the pathophysiological mechanisms underlying this disease remains limited, it is thought to be the hepatic manifestation of more widespread metabolic dysfunction and is strongly associated with a number of metabolic risk factors, including insulin resistance, dyslipidaemia, cardiovascular disease and, most significantly, obesity. Despite this, ”paediatric” NAFLD remains under-studied, under-recognised and, potentially, undermanaged. This article will explore and evaluate our current understanding of NAFLD in childhood and adolescence and how it differs from adult NAFLD, in terms of its epidemiology, pathophysiology, natural history, diagnosis and clinical management. Given the current absence of definitive radiological and histopathological diagnostic tests, maintenance of a high clinical suspicion by all members of the multidisciplinary team in primary and specialist care settings remains the most potent of diagnostic tools, enabling early diagnosis and appropriate therapeutic intervention.

Vitamin D Status and Bone Mineral Density in Obese Children with Nonalcoholic Fatty Liver Disease

Whether nonalcoholic fatty liver disease (NAFLD) is related to vitamin D and bone health in obese children is unknown. The aim of this study was to evaluate vitamin D status and bone mineral density (BMD) in obese children according to their condition within the NAFLD spectrum. Anthropometric data, laboratory tests, and abdominal ultrasonography were obtained from 94 obese children. The subjects were divided into three groups according to NAFLD spectrum: normal liver, simple steatosis, and nonalcoholic steatohepatitis (NASH). Although there were no differences in vitamin D levels between the three groups, these groups showed significant differences in highly sensitive C-reactive protein (P=0.044), homeostasis model assessment of insulin resistance (HOMA-IR) (P=0.02), hepatic fibrosis scores (P<0.05), and trunk fat percentage (P=0.025). Although there were significant differences in BMDs, the age-matched BMD z-scores were not significantly different between the three groups. Serum vitamin D levels were negatively correlated with age (r=-0.368, P=0.023), serum uric acid levels (r=-0.371, P=0.022), fibrosis 4 (FIB4) (r=-0.406, P=0.011), and HOMA-IR (r=-0.530, P=0.001) in obese children with NASH. Multiple regression analysis for vitamin D in the NASH group revealed age and HOMA-IR as significant factors. In conclusion, inflammatory markers, hepatic fibrosis scores, trunk fat, and insulin resistance may reflect the spectrum of NAFLD in obese children, whereas vitamin D levels and BMD may not. In patients with NASH, however, low serum vitamin D is associated with hepatic fibrosis and insulin resistance, but not with bone health status.

Sonographically measured suprailiac adipose tissue is a useful predictor of non-alcoholic fatty liver disease in obese children and adolescents

OBJECTIVE

The objective of the present study was to identify ultrasonographic and anthropometric parameters that are highly associated with the presence of non-alcoholic fatty liver disease (NAFLD) in overweight children and adolescents.

METHODS

A total of 447 overweight children and adolescents (body mass index, 32.4 ± 5.2 kg m(-2) ; mean age, 14.2 ± 1.9 years; range 10.1-20.3 years) were analysed. Subjects underwent ultrasound examination of the liver as well as ultrasonographic measurement of the amount of adipose tissue overlying the biceps brachii and triceps brachii muscles, and of subscapular, suprailiac and abdominal subcutaneous adipose tissue and intra-abdominal depth. Anthropometric parameters such as body mass index, waist and hip circumference were documented.

RESULTS

The prevalence of NAFLD was 27.1%; it was significantly associated with the above-cited anthropometric parameters (P < 0.001). Ultrasonographic findings identified a significant association between NAFLD and the amount of subscapular, suprailiac and abdominal subcutaneous adipose tissue (P < 0.001) as well as between NAFLD and intra-abdominal depth (P < 0.001). Stepwise logistic regression analysis showed only intra-abdominal depth for both gender and the deposit of subcutaneous suprailiac adipose tissue in females to be independent predictors of NAFLD.

CONCLUSIONS

In overweight children and adolescents, we identified intra-abdominal depth for both gender and the ultrasonographically easily determined subcutaneous suprailiac adipose tissue in females as independent predictor of NAFLD.

Improvement of BMI after Lifestyle Intervention Is Associated with Normalisation of Elevated ELF Score and Liver Stiffness in Obese Children

Background. Noninvasive tools to diagnose nonalcoholic fatty liver disease (NAFLD), including transient elastography (TE) and enhanced liver fibrosis panel (ELF), have only been evaluated in children with biopsy-proven NAFLD. We evaluated the prevalence of ELF and TE abnormalities in obese children without clinical liver disease and examined the effects of BMI stabilization on ELF and TE in a longitudinal approach. Methods. 39 obese children (17 m, age 12.3 (7.6–17.4) years) who participated in a 12-month lifestyle-intervention program underwent TE and ELF testing at baseline and at completion of the program. Results were compared with data from a nonobese paediatric cohort. Results. TE and ELF at baseline were significantly elevated compared to controls (TE: 5.9 (3.4–8.3) kPa versus 4.45 (2.45–8.85) kPa, P < 0.01; ELF: 9.0 (7.87–9.60) versus 8.6 (7.33–11.52), P = 0.033). All children with elevated TE and ELF results had normal transaminases. After the program, ELF and TE normalized. Reduction of ELF and TE was associated with a decrease in BMI centile. Conclusion. Abnormal TE and ELF results in obese children suggest presence of NAFLD even when transaminases are normal. TE and ELF might be used as monitoring tools for NAFLD. BMI stabilisation normalizes TE and ELF, underlining the impact of lifestyle intervention.

Increased risk of non-alcoholic fatty liver disease after diagnosis of celiac disease

BACKGROUND & AIMS

Non-alcoholic fatty liver disease is a common cause of chronic liver disease. Celiac disease alters intestinal permeability and treatment with a gluten-free diet often causes weight gain, but so far there are few reports of non-alcoholic fatty liver disease in patients with celiac disease.

METHODS

Population-based cohort study. We compared the risk of non-alcoholic fatty liver disease diagnosed from 1997 to 2009 in individuals with celiac disease (n = 26,816) to matched reference individuals (n = 130,051). Patients with any liver disease prior to celiac disease were excluded, as were individuals with a lifetime diagnosis of alcohol-related disorder to minimize misclassification of non-alcoholic fatty liver disease. Cox regression estimated hazard ratios for non-alcoholic fatty liver disease were determined.

RESULTS

During 246,559 person-years of follow-up, 53 individuals with celiac disease had a diagnosis of non-alcoholic fatty liver disease (21/100,000 person-years). In comparison, we identified 85 reference individuals diagnosed with non-alcoholic fatty liver disease during 1,488,413 person-years (6/100,000 person-years). This corresponded to a hazard ratio of 2.8 (95% CI 2.0-3.8), with the highest risk estimates seen in children (HR = 4.6; 95% CI 2.3-9.1). The risk increase in the first year after celiac disease diagnosis was 13.3 (95% CI 3.5-50.3) but remained significantly elevated even beyond 15 years after the diagnosis of celiac disease (HR = 2.5; 95% CI 1.0-5.9).

CONCLUSION

Individuals with celiac disease are at increased risk of non-alcoholic fatty liver disease compared to the general population. Excess risks were highest in the first year after celiac disease diagnosis, but persisted through 15 years after diagnosis with celiac disease.

The full spectrum of hepatic steatosis in children

OBJECTIVE

We aim to identify the spectrum of etiologies of steatosis in pediatric liver biopsies.

METHODS

Information was collected from 155 children with steatosis on liver biopsy, including anthropometrics, laboratory, and radiologic data. Biopsies were reviewed by a liver pathologist.

RESULTS

The 4 major diagnoses associated with hepatic steatosis were nonalcoholic fatty liver disease (37%), metabolic disease (9%), oncologic disease (8%) and viral hepatitis (7%). Patients with nonalcoholic fatty liver disease were older (P = .0001) and more likely to have a body mass index z score >2 (P < .0001). Patients with a metabolic diagnosis were younger (P = .0002). Radiologic imaging of the liver yielded normal results in 44 of 108 of children (30%); 7 of these had >66% macrovesicular fatty change on biopsy, and 3 had severe fibrosis/cirrhosis.

CONCLUSIONS

The range of causes of steatosis in pediatric liver biopsies is broad. Not all patients, even with advanced liver disease, had abnormalities with liver imaging, emphasizing the role for liver biopsy in certain cases.

Long-Term Treatment with n-3 Polyunsaturated Fatty Acids as a Monotherapy in Children with Nonalcoholic Fatty Liver Disease

OBJECTIVE

To investigate the efficacy and safety of n-3 polyunsaturated fatty acids (PUFA) treatment in obese children with nonalcoholic fatty liver disease (NAFLD).

METHODS

One hundred and eight obese (body mass index (BMI) >95th percentile for age and sex) adolescents with NAFLD were included in the study. Mean age of the subjects was 13.8 ± 3.9 years (9-17 yrs). The diagnosis of NAFLD was based on the presence of liver steatosis with high transaminases. The subjects were randomly divided into two groups. Group 1 (PUFA group, n=52) received a 1000 mg dose of PUFA once daily for 12 months and lifestyle intervention. Group 2 (placebo group, n=56) received a recommended diet plus placebo and lifestyle intervention for 12 months. Insulin resistance was evaluated by homeostasis model assessment of insulin resistance (HOMA-IR) from fasting samples.

RESULTS

BMI, fasting insulin levels and HOMA-IR values in both groups decreased significantly at the end of the study. In group 1, 67.8% of the patients had a decrease from baseline in the prevalence of steatosis (p<0.001). Frequency of elevated alanine aminotransferase (ALT) levels (39.2% to 14.2%; p<0.01) and elevated aspartate aminotransferase (AST) levels (25% to 17.8%; p=0.01) decreased significantly in the PUFA group. Following a 12-month diet plus placebo and lifestyle intervention treatment, 40.3% (21) of the patients in the placebo group also showed a decrease in frequency of steatosis (p=0.04) and slight decreases in frequency of elevated ALT levels (38.4% to 28.8%; p=0.01) and AST levels (30.7% to 28.8%; p>0.05).

CONCLUSION

Our results indicated that n-3 PUFA treatment is safe and efficacious in obese children with NAFLD and can improve ultrasonographic findings and the elevated transaminase levels.

Amount of hepatic fat predicts cardiovascular risk independent of insulin resistance among Hispanic-American adolescents

Background

Nonalcoholic fatty liver disease (NAFLD) has emerged as the major pediatric chronic liver disease, and it is estimated to affect more than one third of obese children in the U.S. Cardiovascular complications are a leading cause of increased mortality in adults with NAFLD and many adolescents with NAFLD already manifest signs of subclinical atherosclerosis including increased carotid intima-media thickness.

Methods

Volume of intrahepatic fat was assessed in 50 Hispanic-American, overweight adolescents, using Magnetic Resonance Spectroscopy. Lipoprotein compositions were measured using Nuclear Magnetic Resonance.

Results

Plasma triglycerides (TG) (p = 0.003), TG/HDL ratio (p = 0.006), TG/apoB ratio (p = 0.011), large VLDL concentration (p = 0.019), VLDL particle size (p = 0.012), as well as small dense LDL concentration (p = 0.026) progressively increased across higher levels of hepatic fat severity, while large HDL concentration progressively declined (p = 0.043). This pattern of associations remained even after controlling for gender, BMI, visceral fat, and insulin resistance.

Conclusions

Our findings suggest that increased hepatic fat is strongly associated with peripheral dyslipidemia and the amount of fat in the liver may influence cardiovascular risk. Further studies are needed to longitudinally monitor dyslipidemia in children with NAFLD and to examine whether the reduction of hepatic fat would attenuate their long-term CVD risk.

Paediatric non-alcoholic fatty liver disease: an overview

Non-alcoholic fatty liver disease (NAFLD) is a progressive disease that encompasses a spectrum of liver diseases, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). Data related to survival in children are scarce, but these data firmly associate NAFLD with higher risks of hepatic and non-hepatic morbidities and mortalities compared with the general population. More recently, the association between NAFLD and cardiovascular disease among children has increasingly been recognized. Given that obesity is a major risk factor for the disease, paediatric NAFLD is becoming a global issue, paralleling the dramatic rise in obesity worldwide. NASH, which is more common in obese children, has the potential to advance to liver fibrosis and failure. It is unclear why certain patients undergo such transformation but this susceptibility is likely related to an interaction between a genetically susceptible host and the surrounding environment. Currently, treatment is largely conservative and includes lifestyle modification, attainable through healthy weight reduction via diet and exercise. In this review, current knowledge about NAFLD in children is summarized. This review aims to increase the awareness of the medical community about a hidden public health issue and to identify current gaps in the literature while providing directions for future research.

Antioxidant vitamins in the context of nonalcoholic fatty liver disease in obese children and adolescents

OBJECTIVE:

To review the literature on the importance of antioxidant vitamins, analyzed in the context of dietary intake, its plasma levels, and its current use as a supplementation treatment in obese children and adolescents with nonalcoholic fatty liver disease.

DATA SOURCES:

The articles were identified in Lilacs, Ibecs, SciELO, PubMed/Medline, and Scopus databases. To conduct the survey, the "fatty liver" descriptor was associated to the following words: "children", "antioxidants" and "vitamins". The search was limited to articles written in Portuguese, Spanish and English, with publication date until December, 2012.

DATA SYNTHESIS:

Six studies were selected. The survey revealed a low dietary intake and low antioxidant vitamins serum levels in this population. The changes in lifestyle, with adequate dietary intake of vitamins, and the increase in physical activity were associated with a significant improvement in liver histology and in laboratory tests. Vitamin supplementation also improved the disease progression markers, as the alanine aminotransferase serum levels and the histological characteristics of lobular inflammation and hepatocellular damage. However, these improvements were not statistically significant in all studies.

CONCLUSIONS:

There is insufficient evidence to recommend or to refute antioxidant supplementation in patients with simple steatosis or steatohepatitis. The changes in lifestyle seem to be, at the present time, the more advisable therapy.

Epidemiology and Natural History of NAFLD

Paralleling the growing prevalence of obesity and metabolic syndrome, nonalcoholic fatty liver disease (NAFLD) is emerging as the most frequent hepatopathy in adults and children. The true prevalence of pediatric NAFLD is still unknown, because of the heterogeneity of diagnostic methods used for diagnosis in the available studies and the different characteristics of the populations evaluated. Pediatric NAFLD is typically of primary origin and it is strongly associated with several features of the metabolic syndrome. Age, gender and race/ethnicity are significant determinants of risk, and sex hormones, insulin sensitivity and adipocytokines are implicated in the pathogenesis of pediatric NAFLD. The natural history of NAFLD in children is still poorly understood, because of its complex nature and the scarcity of prospective studies, especially in pediatric populations. Both genetic and environmental factors seem to be implicated in the development and progression of the disease via multiple mechanisms that involve liver crosstalk with other organs and tissues, especially gut and adipose tissue. To evaluate and effectively treat pediatric NAFLD, the pathophysiology and natural history of the disease should be clarified and noninvasive methods for screening, diagnosis, and longitudinal assessment developed.

Comparison between a pediatric health promotion center and a pediatric obesity clinic in detecting metabolic syndrome and non-alcoholic fatty liver disease in children

This study was done to evaluate the efficacy of health check-ups in children in detecting metabolic syndrome and non-alcoholic fatty liver disease (NAFLD) by comparing the pediatric health promotion center with the pediatric obesity clinic. Children who visited a pediatric health promotion center (n=218) or a pediatric obesity clinic (n=178) were included. Anthropometric data, blood pressure, laboratory tests, and abdominal ultrasonography were evaluated. Two different criteria were applied to diagnose metabolic syndrome. The prevalence of metabolic syndrome in the 2 units was 3.2%-3.7% in a pediatric health promotion center and 23%-33.2% in a pediatric obesity clinic. Significant differences were observed in the prevalence of each component of metabolic syndrome between the 2 units including abdominal adiposity, blood pressure, serum triglycerides, and fasting blood glucose (P<0.05). The prevalence of NAFLD was 8.7% and 71.9% in the 2 units according to liver enzymes and 5.9% and 61.8% according to ultrasonography (P<0.05). The prevalence of metabolic syndrome and NAFLD was higher among patients visiting the obesity clinic targeting obese children than that among patients visiting the health promotion center offering routine check-ups. An obesity-oriented approach is required to prevent obesity-related health problems in children.

Review article: the management of paediatric nonalcoholic fatty liver disease

BACKGROUND

Paediatric nonalcoholic fatty liver disease (NAFLD) is a major public health concern given the recent increase in its prevalence and link to obesity and other metabolic comorbidities. Current treatment strategies involve lifestyle changes. Other surgical and pharmacologic interventions have been proposed; however, limited randomised controlled trials (RCTs) in the paediatric population restrict their use.

AIM

To review the current management of paediatric NAFLD, including lifestyle and pharmacologic interventions, and to formulate recommendations for study design for future studies.

METHODS

A MEDLINE, Pubmed and Cochrane Review database search used a combination of keywords, including NAFLD, nonalcoholic steatohepatitis (NASH), paediatric, treatments, lifestyle changes, bariatric surgery, orlistat, metformin, thiazolidinediones, vitamin E, cysteamine bitartrate, ursodeoxycholic acid (UDCA), probiotics, omega-3 fatty acids, pentoxyfylline, farnesoid X receptor agonist and toll-like receptor modifiers. The articles were selected based on their relevance to the review.

RESULTS

Lifestyle interventions involving diet and exercise remain first-line treatment for paediatric NAFLD. Bariatric surgery, orlistat, insulin sensitisers and UDCA have been evaluated but are not recommended as first or second-line therapy. Medications such as cysteamine bitartrate, probiotics, polyunsaturated fats and pentoxyfilline share beneficial effects in trials, however, there is a paucity of adequately powered RCTs in which liver histology is evaluated. Vitamin E has been shown to be effective and safe in improving NASH histology in children.

CONCLUSIONS

Lifestyle intervention should be first-line treatment for paediatric NAFLD. Vitamin E should be considered for those with biopsy-proven NASH or borderline NASH failing first-line therapy. Other therapeutics show promising results but require larger RCTs with convincing endpoints. Improved screening techniques, objective validated inclusion criteria and outcome measures as well as rigour in study design are necessary for propelling therapeutic discovery.

Dietary fructose reduction improves markers of cardiovascular disease risk in Hispanic-American adolescents with NAFLD

Nonalcoholic fatty liver disease (NAFLD) is now thought to be the most common liver disease worldwide. Cardiovascular complications are a leading cause of mortality in NAFLD. Fructose, a common nutrient in the westernized diet, has been reported to be associated with increased cardiovascular risk, but its impact on adolescents with NAFLD is not well understood. We designed a 4-week randomized, controlled, double-blinded beverage intervention study. Twenty-four overweight Hispanic-American adolescents who had hepatic fat >8% on imaging and who were regular consumers of sweet beverages were enrolled and randomized to calorie-matched study-provided fructose only or glucose only beverages. After 4 weeks, there was no significant change in hepatic fat or body weight in either group. In the glucose beverage group there was significantly improved adipose insulin sensitivity, high sensitivity C-reactive protein (hs-CRP), and low-density lipoprotein (LDL) oxidation. These findings demonstrate that reduction of fructose improves several important factors related to cardiovascular disease despite a lack of measurable improvement in hepatic steatosis. Reducing dietary fructose may be an effective intervention to blunt atherosclerosis progression among NAFLD patients and should be evaluated in longer term clinical trials.

Low 25-hydroxyvitamin D level is associated with insulin sensitivity in obese adolescents with non-alcoholic fatty liver disease

AIM

The aim of this study was to investigate the relationships between 25-hydroxy-vitamin D (25(OH)D) and insulin resistance in obese adolescents with non-alcoholic fatty liver disease (NAFLD).

PATIENTS AND METHODS

Eighty-seven obese adolescents (45 girls and 42 boys, mean age: 12.7 ± 1.3 years, mean body mass index standard deviation score (BMI-SDS): 2.1 ± 0.3) and 30 lean subjects (15 girls and 15 boys, mean age: 12.3 ± 1.45 years, mean BMI-SDS: 0.5 ± 0.7) were enrolled for the study. The obese subjects were divided into two subgroups based on the presence or absence of fatty liver with high transaminases (NAFLD group and non-NAFLD group). Fasting blood samples were assayed for 25(OH)D, transaminases, glucose, and insulin levels. Insulin resistance was calculated by the homeostasis model assessment (HOMA-IR).

RESULTS

25(OH)D measurements were decreased in both obese groups (NAFLD and non-NAFLD) in comparison with the lean group (29.5 ± 18.4 vs. 41.0 ± 17.9 vs. 48.1 ± 22.2 ng/mL). However; the NAFLD group had significantly lower measurements of 25(OH)D than the non-NAFLD group (p < 0.001) and lean group (p < 0.001). 25(OH)D was negatively correlated with HOMA-IR (r = 0.158, p = 0.01) and with alanine aminotransferase (r = 0.794, p = 0.03) in the NAFLD obese group. There was no significant associations between fasting insulin, BMI-SDS and 25(OH)D in obese groups.

CONCLUSION

We suggest that low 25(OH)D occurs commonly in obese adolescents with NAFLD and we demonstrated an association between insufficient vitamin D status and low insulin sensitivity in obese adolescents with NAFLD.

Prevalence, risk factors, and predictors of nonalcoholic fatty liver disease among schoolchildren: a hospital-based study in Alexandria, Egypt

BACKGROUND AND STUDY AIMS

Nonalcoholic fatty liver disease (NAFLD) is an emerging problem in children and adolescents worldwide. This study was done to investigate the prevalence of NAFLD in children and adolescents as well as to determine the associated risk factors of fatty liver and to explore the ability of some obesity indices to predict and consequently be used as a screening method of fatty liver disease at certain cutoff points in schoolchildren.

PATIENTS AND METHODS

A cross-sectional, nested case-control study was carried out. Cases and controls were randomly selected from outpatient schoolchildren aged 6-18years attending the radiology clinic at Sporting Health Insurance Paediatric Hospital in Alexandria. They were subjected to ultrasonic examination as well as complete anthropometric and laboratory measurements including fasting plasma glucose (FPG) level, fasting insulin, alanine aminotransferase (ALT) level, and lipid profile.

RESULTS

Fatty liver was prevalent in schoolchildren (15.8%) and increased significantly with age (p=0.004). Positive family history of diabetes mellitus (DM), hypertension (HTN), obesity, and liver disease were all statistically significant risk factors for fatty liver. Waist circumference (WC), body mass index (BMI) and its Z-score were significantly sensitive predictors. BMI was considered the best predictor of paediatric NAFLD at a cutoff=22.9. NAFLD was significantly associated with high triglycerides (TGs), low high-density lipoprotein cholesterol (HDL), homoeostatic model assessment (HOMA) percentile, and the number of metabolic syndrome (MS) components.

CONCLUSION

Paediatric NAFLD is a substantial problem in schoolchildren and has a close relationship with obesity, dyslipidaemia, insulin resistance (IR), and consequently MS. BMI and WC can be used as useful predictors and screening tools for NAFLD in schoolchildren.

Pediatric fatty liver disease: Role of ethnicity and genetics

Non-alcoholic fatty liver disease (NAFLD) comprehends a wide range of conditions, encompassing from fatty liver or steatohepatitis with or without fibrosis, to cirrhosis and its complications. NAFLD has become the most common form of liver disease in childhood as its prevalence has more than doubled over the past 20 years, paralleling the increased prevalence of childhood obesity. It currently affects between 3% and 11% of the pediatric population reaching the rate of 46% among overweight and obese children and adolescents. The prevalence of hepatic steatosis varies among different ethnic groups. The ethnic group with the highest prevalence is the Hispanic one followed by the Caucasian and the African-American. This evidence suggests that there is a strong genetic background in the predisposition to fatty liver. In fact, since 2008 several common gene variants have been implicated in the pathogenesis of fatty liver disease. The most important is probably the patatin like phospholipase containing domain 3 gene (PNPLA3) discovered by the Hobbs’ group in 2008. This article reviews the current knowledge regarding the role of ethnicity and genetics in pathogenesis of pediatric fatty liver.

Autophagy protects against palmitate-induced apoptosis in hepatocytes

Background

Non-alcoholic fatty liver disease, one of the most common liver diseases, has obtained increasing attention. Palmitate (PA)-induced liver injury is considered a risk factor for the development of non-alcoholic fatty liver disease. Autophagy, a cellular degradative pathway, is an important self-defense mechanism in response to various stresses. In this study, we investigated whether autophagy plays a protective role in the progression of PA-induced hepatocytes injury.

Results

Annexin V-FITC/PI staining by FCM analysis, TUNEL assay and the detection of PARP and cleaved caspase3 expression levels demonstrated that PA treatment prominently induced the apoptosis of hepatocytes. Meanwhile, treatment of PA strongly induced the formation of GFP-LC3 dots, the conversion from LC3I to LC3II, the decrease of p62 protein levels and the increase of autophagosomes. These results indicated that PA also induced autophagy activation. Autophagy inhibition through chloroquine pretreatment or Atg5shRNA infection led to the increase of cell apoptosis after PA treatment. Moreover, induction of autophagy by pretreatment with rapamycin resulted in distinct decrease of PA-induced apoptosis. Therefore, autophagy can prevent hepatocytes from PA-induced apoptosis. In the further study, we explored pathway of autophagy activation in PA-treated hepatocytes. We found that PA activated PKCα in hepatocytes, and had no influence on mammalian target of rapamycin and endoplasmic reticulum stress pathways.

Conclusions

These results demonstrated that autophagy plays a protective role in PA-induced hepatocytes apoptosis. And PA might induce autophagy through activating PKCα pathway in hepatocytes.

Pediatric non-alcoholic fatty liver disease: New insights and future directions

One of the most common complications of childhood obesity is the non-alcoholic fatty liver disease (NAFLD), which is the most common form of liver disease in children. NAFLD is defined by hepatic fat infiltration > 5% hepatocytes, as assessed by liver biopsy, in the absence of excessive alcohol intake, viral, autoimmune and drug-induced liver disease. It encompasses a wide spectrum of liver diseases ranging from simple steatosis to non-alcoholic steatohepatitis, which, in turn, can evolve into cirrhosis and end stage liver disease. Obesity and insulin resistance are the main risk factors for pediatric NAFLD. In fact, NAFLD is strongly associated with the clinical features of insulin resistance especially the metabolic syndrome, prediabetes and type 2 diabetes mellitus (T2D). In particular, it has been clearly shown in obese youth that the prevalence of metabolic syndrome, pre-diabetes and type 2 diabetes increases with NAFLD severity progression. Evidence that not all of the obese patients develop NAFLD suggests that the disease progression is likely to depend on complex interplay between environmental factors and genetic predisposition. Recently, a non-synonymous SNP (rs738409), characterized by a C to G substitution encoding an isoleucine to methionine substitution at the amino acid position 148 in the patatin like phospholipase containing domain 3 gene (PNPLA3), has been associated with hepatic steatosis in a multiethnic cohort of adults as well as in children. Another important polymorphisms that acts with PNPLA3 to convey susceptibility to fatty liver in obese youths is the rs1260326 polymorphism in the glucokinase regulatory protein. The pharmacological approach in NAFLD children poorly adherent to or being unresponsive/partially responsive to lifestyle changes, is aimed at acting upon specific targets involved in the pathogenesis. There are some therapeutic approaches that are being studied in children. This article reviews the current knowledge regarding the pediatric fatty liver disease, the new insights and the future directions.

Genetic predisposition in NAFLD and NASH: impact on severity of liver disease and response to treatment

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.

Body composition variables as predictors of NAFLD by ultrasound in obese children and adolescents

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a disorder associated with excessive fat accumulation, mainly in the intra-abdominal region. A simple technique to estimate abdominal fat in this region could be useful to assess the presence of NAFLD, in obese subjects who are more vulnerable to this disease. The aim of this cross-sectional study was to verify the reliability of waist circumference and body composition variables to identify the occurrence of NAFLD in obese children and adolescents.

METHODS

Sample was composed of 145 subjects, aged 11 to 17 years. Assessments of waist circumference (WC), trunk fat mass (TFM) and fat mass (FM) by dual-energy X-ray absorptiometry (DXA) and ultrasound for diagnosis of NAFLD and intra-abdominal adipose tissue (IAAT) were used. Correlation between variables was made by Spearman's coefficients; ROC curve parameters (sensitivity, specificity, area under curve) were used to assess the reliability of body composition variables to assess the presence of NAFLD. Statistical significance was set at 5%.

RESULTS

Significant correlations were observed between NAFLD and WC (p = 0.001), TFM (p = 0.002) and IAAT (p = 0.001). The higher values of area under the ROC curve were for WC (AUC = 0.720), TFM (AUC = 0.661) and IAAT (AUC = 0.741).

CONCLUSIONS

Our findings indicated that TFM, IAAT and WC present high potential to identify NAFLD in obese children and adolescents.

Impact of new-generation lipid emulsions on cellular mechanisms of parenteral nutrition-associated liver disease

Parenteral nutrition (PN) is a life-saving nutritional support for a large population of hospitalized infants, and lipids make a substantial contribution to their energy and essential fatty acid (FA) needs. A challenge in the care of these infants is that their metabolic needs require prolonged PN support that increases the risk of PN-associated liver disease (PNALD). In recent years, the emergence of new parenteral lipid emulsions containing different source lipids and FA profiles has created nutritional alternatives to the first-generation, soybean oil-based lipid emulsion Intralipid. The limited U.S. introduction of the new-generation fish-oil emulsion Omegaven has generated promising results in infants with PNALD and spawned a renewed interest in how PN and lipid emulsions, in particular, contribute to this disease. Studies suggest that the lipid load and constituents, such as specific FAs, ratio of n-3 (ω-3) to n-6 (ω-6) long-chain polyunsaturated FAs, phytosterols, and vitamin E content, may be involved. There is an existing literature describing the molecular mechanisms whereby these specific nutrients affect hepatic metabolism and function via lipid and bile acid sensing nuclear receptors, such as peroxisome proliferator-activated receptor α, liver X receptor, and farnesoid X receptor, yet virtually no information as to how they interact and modulate liver function in the context of PN in pediatric patients or animal models. This article will review the recent development of parenteral lipid emulsions and their influence on PNALD and highlight some of the emerging molecular mechanisms that may explain the effects on liver function and disease.

Systematic review with meta-analysis: non-alcoholic steatohepatitis - a case for personalised treatment based on pathogenic targets

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is an umbrella term, which encompasses simple steatosis and non-alcoholic steatohepatitis (NASH). The entire spectrum of NAFLD has been associated with metabolic syndrome. NASH is associated with increased mortality compared with that of the general population. Many therapeutic options for NASH have been studied. However, there is very little evidence supporting the efficacy of most regimens for the treatment of NASH.

AIM

To provide a review focusing on the current therapeutic options available for patients with NASH as well as to briefly introduce possible future interventions.

METHODS

A MEDLINE, Pubmed and Cochrane Review database search using a combination of keywords, which included non-alcoholic fatty liver disease, non-alcoholic hepatic steatosis, NAFLD, NASH, treatment, therapeutics, vitamin E, orlistat and bariatric surgery. An overall summary of the articles was developed for each section of discussion in this review.

RESULTS

NASH associated with metabolic syndrome can progress advanced fibrosis and cirrhosis. Weight loss and lifestyle modification have been shown to improve NASH. Other medications used for weight loss and metabolic syndrome have been evaluated, such as orlistat, metformin and thiazolidinediones. Alternative regimens using ursodeoxycholic acid, statins and probiotics as well as bariatric surgery have been evaluated, but have not been recommended as first-line treatment for NASH. Vitamin E for NASH patients without diabetes seems to be promising. The lack of effective treatment for NASH suggests the heterogeneity of patients presenting with the NASH phenotype. The best treatment strategy for these patients may be to identify their pathogenic target and develop personalised treatment protocols.

CONCLUSIONS

Currently, there are few options available for the management of NASH. Future targeted treatment strategies based on the pathogenic pathways may be needed to develop effective treatment for patients with NASH.

MTTP polymorphisms and susceptibility to non-alcoholic fatty liver disease in a Han Chinese population

BACKGROUND

The microsomal triglyceride transfer protein (MTP) is required for the assembly and secretion of apolipoprotein B (ApoB)-containing lipoproteins from the liver and intestine. Previous studies showed that functional polymorphisms in the MTTP gene correspond to lower LDL levels and protect against other traits of the metabolic syndrome.

AIMS

Here, we aimed to investigate whether MTTP single nucleotide polymorphisms (SNPs) and their predicted haplotypes of linkage disequilibrium blocks contribute to non-alcoholic fatty liver disease (NAFLD) susceptibility in a Han Chinese population.

METHODS

Seven tag SNPs in the MTTP gene were selected and genotyped in a frequency-matched case-control study in a population from Fuzhou City, China. We enrolled 580 patients with NAFLD and 580 healthy controls.

RESULTS

In the multivariate logistic regression analysis, the rs1800804 (-164 T/C) was associated with an increased risk of NAFLD, while the rs1057613 A/G and rs3805335 C/T SNPs were associated with a decreased risk of NAFLD. The cumulative effect of the rs1800804 (-164 T/C), rs1057613 and rs3805335 was estimated, and a significant increased trend in the risk of NAFLD with increasing genetic risk score was observed (adjusted P(trend) = 0.014). Furthermore, the results of haplotype analysis suggested that the haplotype GC in block 1 containing the -164 C allele was associated with an increased risk of NAFLD, while haplotype TGTTC in block 2 was associated with a decreased risk of NAFLD.

CONCLUSIONS

Our data show that MTTP genetic polymorphisms influence the susceptibility to developing NAFLD independently or jointly in the Han Chinese population.