Pediatric nonalcoholic fatty liver disease: A clinical and laboratory challenge

Impact of Weight Reduction on Thyroid Function and Nonalcoholic Fatty Liver among Egyptian Adolescents with Obesity

BACKGROUND

The prevalence of childhood obesity has been increasing worldwide. This may explain the emergence of nonalcoholic fatty liver as the leading cause of liver disease. Several previous studies have addressed the association between thyroid function and nonalcoholic fatty liver disease.

OBJECTIVES

To study the impact of weight reduction through lifestyle modifications in adolescents with obesity.

METHODS

A prospective cohort study was done on 61 adolescents with obesity. Patients were evaluated at the first visit by the full history, clinical examination, and investigations (thyroid profile, lipid profile, liver function tests, HbA1c, and liver ultrasonography) as basal information. The intervention program included a dietary program, increasing physical activity, and decreasing sedentary activity. A postintervention evaluation was done at the end of six months which included anthropometric measures, laboratory results, and ultrasonographic estimation.

RESULTS

It was shown that the mean BMI of the participants had significantly decreased after lifestyle modification from (32.05 ± 3.36 kg/m2) to (28.1 ± 2.77 kg/m2) (P < 0.001). It also showed that the percentage of studied adolescents with elevated TSH decreased from 47.5% to 19.7% after the weight reduction program. Improvement was also achieved in the lipid profile and liver functions. The percentage of studied adolescents with ultrasound appearance of NAFLD decreased from 31.1% to 26.2% after weight reduction.

CONCLUSIONS

Lifestyle modification positively influences the metabolic derangement in obesity without medical treatment. ΔTSH is a significant predictor of the change in BMI z-score. It is also possible that hepatic steatosis affects thyroid function rather than the other way around.

Performance of Imaging Techniques in Non-invasive Diagnosis of Non-alcoholic Fatty Liver Disease in Children: A Systematic Review and Meta-Analysis

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease in children. With the continuous emergence of various non-invasive diagnostic methods, imaging techniques have always been considered as potential alternative methods to liver biopsy. This study aimed to evaluate the diagnostic performance of imaging techniques so as to search for the most promising technology.

METHODS

We searched English and Chinese databases. English databases included Cochran library, Embase, PubMed, and Web of Science, while Chinese databases included the Wanfang database and China National Knowledge Internet.

RESULTS

Finally, 11 articles were included (12 studies, one of which included studies on both fibrosis and steatosis). Further, 26.2% of the participants had mild steatosis, 34.1% had moderate steatosis, and 34.9% had severe steatosis. Also, 64.0% had any fibrosis, 29.1% had significant fibrosis, 13.8% had advanced fibrosis, and 2.8% had cirrhosis. Irrespective of the grade of fibrosis, transient elastography (TE) had higher sensitivity (97-100%), whereas magnetic resonance elastography (MRE) had the lowest sensitivity (58-63%). The pooled sensitivity and specificity of imaging techniques in diagnosing steatosis were 89% (95% CI, 71-96) and 89% (95% CI, 72-96), and AUROC 0.95 (95% CI, 93-97), multifrequency magnetic resonance elastography-hepatic fat fraction (mMRE-HFF) had the highest sensitivity (87%, 95% CI 77-97), ultrasonography (US) had the lowest specificity (96%, 95% CI 92-98%).

CONCLUSION

Imaging techniques have a good diagnostic performance for children with NAFLD, especially the diagnosis of liver fibrosis based on ultrasound or magnetic resonance elastography. Compared with different imaging techniques, TE has the best performance in diagnosing significant fibrosis. Liver stiffness measurement (LSM) is expected to become a biological indicator for routine screening, dynamic monitoring of disease changes, and prognostic evaluation.

Metabolic Associated Fatty Liver Disease in Children-From Atomistic to Holistic

Non-alcoholic fatty liver disease has become the most common chronic liver disease in children due to the alarmingly increasing incidence of pediatric obesity. It is well-documented that MAFLD prevalence is directly related to an incremental increase in BMI. The multiple hits theory was designed for providing insights regarding the pathogenesis of steatohepatitis and fibrosis in MAFLD. Recent evidence suggested that the microbiome is a crucial contributor in the pathogenesis of MAFLD. Aside from obesity, the most common risk factors for pediatric MAFLD include male gender, low-birth weight, family history of obesity, MAFLD, insulin resistance, type 2 diabetes mellitus, obstructive sleep apnea, and polycystic ovarium syndrome. Usually, pediatric patients with MAFLD have nonspecific symptoms consisting of fatigue, malaise, or diffuse abdominal pain. A wide spectrum of biomarkers was proposed for the diagnosis of MAFLD and NASH, as well as for quantifying the degree of fibrosis, but liver biopsy remains the key diagnostic and staging tool. Nevertheless, elastography-based methods present promising results in this age group as potential non-invasive replacers for liver biopsy. Despite the lack of current guidelines regarding MAFLD treatment in children, lifestyle intervention was proven to be crucial in the management of these patients.

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.

Abnormal fatty acid metabolism is a core component of spinal muscular atrophy

OBJECTIVE

Spinal muscular atrophy (SMA) is an inherited neuromuscular disorder leading to paralysis and subsequent death in young children. Initially considered a motor neuron disease, extra-neuronal involvement is increasingly recognized. The primary goal of this study was to investigate alterations in lipid metabolism in SMA patients and mouse models of the disease.

METHODS

We analyzed clinical data collected from a large cohort of pediatric SMA type I-III patients as well as SMA type I liver necropsy data. In parallel, we performed histology, lipid analysis, and transcript profiling in mouse models of SMA.

RESULTS

We identify an increased susceptibility to developing dyslipidemia in a cohort of 72 SMA patients and liver steatosis in pathological samples. Similarly, fatty acid metabolic abnormalities were present in all SMA mouse models studied. Specifically, Smn2B/- mice displayed elevated hepatic triglycerides and dyslipidemia, resembling non-alcoholic fatty liver disease (NAFLD). Interestingly, this phenotype appeared prior to denervation.

INTERPRETATION

This work highlights metabolic abnormalities as an important feature of SMA, suggesting implementation of nutritional and screening guidelines in patients, as such defects are likely to increase metabolic distress and cardiovascular risk. This study emphasizes the need for a systemic therapeutic approach to ensure maximal benefits for all SMA patients throughout their life.

Association between Vitamin D Levels and Nonalcoholic Fatty Liver Disease: Potential Confounding Variables

Nonalcoholic fatty liver disease (NAFLD), historically considered to be the hepatic component of the metabolic syndrome, is a spectrum of fat-associated liver conditions, in the absence of secondary causes, that may progress to nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. Disease progression is closely associated with body weight or fatness, dyslipidemia, insulin resistance, oxidative stress, and inflammation. Recently, vitamin D deficiency has been linked to the pathogenesis and severity of NAFLD because of vitamin D "pleiotropic" functions, with roles in immune modulation, cell differentiation and proliferation, and regulation of inflammation. Indeed, several studies have reported an association between vitamin D and NAFLD/NASH. However, other studies have failed to find an association. Therefore, we sought to critically review the current evidence on the association between vitamin D deficiency and NAFLD/NASH, and to analyze and discuss some key variables that may interfere with this evaluation, such as host-, environment-, and heritability-related factors regulating vitamin D synthesis and metabolism; definitions of deficient or optimal vitamin D status with respect to skeletal and nonskeletal outcomes including NAFLD/NASH; methods of measuring 25(OH)D; and methods of diagnosing NAFLD as well as quantifying adiposity, the cardinal link between vitamin D deficiency and NAFLD.

The Liver in Children With Metabolic Syndrome

Non-alcoholic fatty liver disease (NAFLD) is recognized as an emerging health risk in obese children and adolescents. NAFLD represents a wide spectrum of liver conditions, ranging from asymptomatic steatosis to steatohepatitis. The growing prevalence of fatty liver disease in children is associated with an increased risk of metabolic and cardiovascular complications. NAFLD is considered the hepatic manifestation of Metabolic Syndrome (MetS) and several lines of evidence have reported that children with NAFLD present one or more features of MetS. The pathogenetic mechanisms explaining the interrelationships between fatty liver disease and MetS are not clearly understood. Altough central obesity and insulin resistance seem to represent the core of the pathophysiology in both diseases, genetic susceptibility and enviromental triggers are emerging as crucial components promoting the development of NAFLD and MetS in children. In the present review we have identified and summarizied studies discussing current pathogenetic data of the association between NAFLD and MetS in children.

Advances in Pediatric Fatty Liver Disease: Pathogenesis, Diagnosis, and Treatment

Pediatric nonalcoholic fatty liver disease is an increasingly prevalent disease, but its pathophysiology is not fully elucidated, diagnosis is difficult and invasive, and therapeutic options are limited. This article addresses the recent advancements made in understanding the pathophysiology of nonalcoholic fatty liver disease, the development of less invasive diagnostic modalities, and emerging therapeutic options, including ongoing clinical trials in children.

Mediterranean diet and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is emerging as the most common chronic liver disease, and is characterized by a wide spectrum of fat-liver disorders that can result in severe liver disease and cirrhosis. Inflammation and oxidative stress are the major risk factors involved in the pathogenesis of NAFLD. Currently, there is no consensus concerning the pharmacological treatment of NAFLD. However, lifestyle interventions based on exercise and a balanced diet for quality and quantity, are considered the cornerstone of NAFLD management. Mediterranean diet (MD), rich in polyunsaturated fats, polyphenols, vitamins and carotenoids, with their anti-inflammatory and anti-oxidant effects, has been suggested to be effective in preventing cardiovascular risk factors. In adults, MD has also been demonstrated to be efficacious in reducing the risk of metabolic syndrome. However, few studies are available on the effects of the MD in both adult and pediatric subjects with NAFLD. Thus, the aims of the present narrative review are to analyze the current clinical evidence on the impact of MD in patients with NAFLD, and to summarize the main mechanisms of action of MD components on this condition.

Design and rationale for a real-world observational cohort of patients with nonalcoholic fatty liver disease: The TARGET-NASH study

Nonalcoholic fatty liver disease (NAFLD) is highly prevalent and can lead to cirrhosis, hepatocellular carcinoma, and end-stage liver disease. NAFLD comprises the spectrum from simple steatosis (nonalcoholic fatty liver, NAFL), to steatosis with inflammation (nonalcoholic steatohepatitis, NASH). Current primary therapy recommended for NAFLD is weight loss induced by lifestyle modification. The difficulty in achieving this has led to robust pharmacological therapy development. While new drugs may show efficacy in selected phase II/III clinical trial populations, their real-world effectiveness is unknown. TARGET-NASH is a 5-year, longitudinal, observational study of patients with NAFLD designed to evaluate the effectiveness of clinical practice interventions and provide practical information unobtainable in registration trials. A biological specimen repository is included in TARGET-NASH for translational studies of genomics and biomarkers of disease activity. Patients are enrolling at adult and pediatric sites representing multiple specialties. All patients being managed for NAFLD are eligible, whereas those in other NASH registries or clinical trials will be excluded. Enrolled patients range in age from 6 and up and will have 3years of clinical data reviewed. Patient comorbidities, concomitant medications, disease progression and off-label interventions will be assessed, and adverse outcomes, monitored. Confirming the use, safety and effectiveness of NAFLD interventions in children and adults and establishing pragmatic methods of assessing disease progression under real-world conditions are key study outcomes. Ultimately, TARGET-NASH will establish a large, diverse registry of NAFLD patients at academic and community practices to be leveraged to improve health and reduce development of cirrhosis and hepatocellular carcinoma.

Elevated Liver Enzymes: Emergency Department-Focused Management

BACKGROUND

Liver function test (LFT) abnormalities are a common problem faced by emergency physicians. This has become more common with the introduction of laboratory panels and automated routine laboratory testing. Fortunately, not all patients with irregularities in liver enzymes possess underlying pathology. This emergency medicine focused review provides a discussion of the various biochemical tests, their underlying biological basis, and an algorithmic approach to the interpretation of abnormalities.

OBJECTIVE

Our aim was to provide emergency physicians with an overview of the evaluation and management of patients with elevated LFTs.

DISCUSSION

The liver is a complex organ with multiple roles. The key biochemical markers of hepatic function can be organized into the groupings of hepatocellular, cholestatic, or functioning liver, based on underlying enzymatic roles. Pathologic alterations to these markers can be algorithmically assessed by separating disease processes of these groupings, followed by assessment of the magnitude of enzymatic elevation. This review conducts an in-depth evaluation of the differential diagnosis and emergency department-centered clinical response of elevated LFTs based on subcategories of mild, moderate, and severe transaminase elevation.

CONCLUSIONS

By understanding the biochemical basis of each LFT, it is possible to correlate laboratory findings to a patient's clinical presentation. An algorithmic approach can be taken to help narrow the spectrum of a differential diagnosis. This may assist providers in ensuring appropriate management and evaluation of the patient with elevated LFTs.

Global Epidemiology of Nonalcoholic Fatty Liver Disease and Perspectives on US Minority Populations

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a clinical syndrome predicted to be the next global epidemic affecting millions of people worldwide. The natural course of this disease including its subtype, non-alcoholic steatohepatitis (NASH), is not clearly defined especially in the African-American segment of the US population.

AIMS

To conduct a review of the global epidemiology of NAFLD with emphasis on US minority populations.

METHODS

A thorough search of evidence-based literature was conducted using the Pubmed database and commercial web sources such as Medscape and Google Scholar.

RESULTS

NAFLD and its subtype NASH are becoming the principal cause of chronic liver disease across the world. In the US, Hispanics are the most disproportionately affected ethnic group with hepatic steatosis, and elevated aminotransferase levels, whereas African-Americans are the least affected. Genetic disparities involved in lipid metabolism seem to be the leading explanation for the lowest incidence and prevalence of both NAFLD and NASH in African-Americans.

CONCLUSIONS

The unprecedented rise in the prevalence of NAFLD globally requires an initiation of population cohort studies with long-term follow-up to determine the incidence and natural history of NAFLD and its underrepresentation in African-Americans. Future studies should also focus on the delineation of the interplay between genetic and environmental factors that trigger the development of NAFLD and NASH.

Prevalence of Non-alcoholic Fatty Liver Disease and Its Related Factors in Iran

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease in developing and developed countries. Estimating the total prevalence of NAFLD by means of appropriate statistical methods can provide reliable evidence for health policy makers.

OBJECTIVE

To determine the prevalence of NAFLD in Iran using a systematic review and meta-analysis.

METHODS

We identified relevant studies by searching national and international databases. Standard error of the prevalence reported in each study was calculated assuming a binomial distribution. The heterogeneity between the results of the studies was determined using Cochran's Q and I square indices. We used a random effect model to combine the prevalence rates reported in the studies.

RESULTS

We entered 23 eligible studies in this systematic review investigated NAFLD among 25,865 Iranian people. The total prevalence of NAFLD, prevalence of mild, moderate and severe fatty liver disease were estimated at 33.9% (95% CI 26.4%-41.5%), 26.7% (95% CI 21.7%-31.7%), 7.6% (95% CI 5.7%-9.4%), and 0.5% (95% CI 0.1%-0.9%), respectively. The majority of studies reported that NAFLD was more common among men (seven of eight studies), obese person (15 of 15 studies), older people (10 of 10 studies), patients with systolic hypertension (5 of 8 studies), patients with diastolic hypertension (7 of 9 studies), patients with hypertriglyceridemia (14 of 16 studies), patients with high HOMA level (4 of 4 studies), patients with metabolic syndrome (4 of 4 studies), and those with elevated serum ALT (8 of 12 studies).

CONCLUSION

Our study showed that the prevalence of NAFLD in Iran was relatively high and male gender, old age, diabetes, metabolic syndrome, systolic/diastolic hypertension, high serum ALT, and hypertriglyceridemia may be determinants of NAFLD.

Accuracy of computer-aided ultrasound as compared with magnetic resonance imaging in the evaluation of nonalcoholic fatty liver disease in obese and eutrophic adolescents

OBJECTIVE

To compare the accuracy of computer-aided ultrasound (US) and magnetic resonance imaging (MRI) by means of hepatorenal gradient analysis in the evaluation of nonalcoholic fatty liver disease (NAFLD) in adolescents.

MATERIALS AND METHODS

This prospective, cross-sectional study evaluated 50 adolescents (aged 11-17 years), including 24 obese and 26 eutrophic individuals. All adolescents underwent computer-aided US, MRI, laboratory tests, and anthropometric evaluation. Sensitivity, specificity, positive and negative predictive values and accuracy were evaluated for both imaging methods, with subsequent generation of the receiver operating characteristic (ROC) curve and calculation of the area under the ROC curve to determine the most appropriate cutoff point for the hepatorenal gradient in order to predict the degree of steatosis, utilizing MRI results as the gold-standard.

RESULTS

The obese group included 29.2% girls and 70.8% boys, and the eutrophic group, 69.2% girls and 30.8% boys. The prevalence of NAFLD corresponded to 19.2% for the eutrophic group and 83% for the obese group. The ROC curve generated for the hepatorenal gradient with a cutoff point of 13 presented 100% sensitivity and 100% specificity. As the same cutoff point was considered for the eutrophic group, false-positive results were observed in 9.5% of cases (90.5% specificity) and false-negative results in 0% (100% sensitivity).

CONCLUSION

Computer-aided US with hepatorenal gradient calculation is a simple and noninvasive technique for semiquantitative evaluation of hepatic echogenicity and could be useful in the follow-up of adolescents with NAFLD, population screening for this disease as well as for clinical studies.

Association of Nonalcoholic Fatty Liver Disease with Subclinical Cardiovascular Changes: A Systematic Review and Meta-Analysis

In the last 20 years, nonalcoholic fatty liver disease (NAFLD) has become the leading cause of chronic liver disease worldwide, primarily as a result of the epidemic of obesity. NAFLD is strongly associated with insulin resistance, glucose intolerance, and dyslipidemia and is currently regarded as the liver manifestation of the metabolic syndrome, a highly atherogenic condition even at a very early age. Patients with NAFLD including pediatric subjects have a higher prevalence of subclinical atherosclerosis, as shown by impaired flow-mediated vasodilation, increased carotid artery intima-media thickness, and arterial stiffness, which are independent of obesity and other established risk factors. More recent work has identified NAFLD as a risk factor not only for premature coronary heart disease and cardiovascular events, but also for early subclinical abnormalities in myocardial structure and function. Thus, we conducted a systematic review and meta-analysis to test the hypothesis that NAFLD is associated with evidence of subclinical cardiac structural and functional abnormalities.

Cord serum dipeptidyl-peptidase 4 activity in gestational diabetes

BACKGROUND

Tissue-specific dipeptidyl-peptidase 4 (DPP4) dysregulation has been described in adults with diabetes mellitus. The DPP4 -incretin system has not been studied in foetal life. In this study, DPP4 activity and glucagon-like peptide-1 (GLP-1) levels were assessed in cord blood of neonates born to women with gestational diabetes mellitus (GDM) and nondiabetic controls.

MATERIAL AND METHODS

This study has been conducted in two Hungarian and one Austrian centres.

PATIENTS

A total of 568 pregnant women were enrolled in the study after their OGTT between the 24th and 28th gestational week. Cord blood samplings with DPP4 activity and GLP-1 level measurements were possible in 270 (DPP4: 159 control, 111 GDM) and 112 (GLP-1: 72 control, 40 GDM) cases. OGTT (24-28th gestational week) and cord blood sampling at delivery were performed. Cord serum DPP4 activity was determined in a continuous monitoring microplate-based kinetic assay, and cord plasma GLP-1 was measured using a fluorescence ELISA method.

RESULTS

Cord serum DPP4 activity was lower in GDM [mean (95% CI): 28.07 U/L (26.32-29.82 U/L)] than in controls [31.61 U/L (29.93-33.29 U/L), MWU P = 0.0015]. Cord plasma active GLP-1 levels were close to the lower detection limit and were not altered in GDM (control: mean = 3.43 pM, 95% CI: 3.04-3.82 pM, GDM: mean = 3.61 pM, 95% CI: 2.96-4.28 pM - MWU test P = 0.6).

CONCLUSIONS

Decreased cord serum DPP4 activity in gestational diabetes mellitus might be the result of an adaptive foetal response or an early dysregulation in the entero-insular axis with consequences beyond the incretin system. Cord plasma GLP-1 levels may reflect the missing oral intake with a limited glucose sensing of L cells via the circulation in foetal life.

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.

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.

Changes of liver fat content and transaminases in obese children after 12-mo nutritional intervention

AIM: To assess a relationship between longitudinal changes in liver fat content and biochemical parameters in obese children after 1-year nutritional intervention.

METHODS: Forty-six obese children, 21 males and 25 females, aged 6-14 years, underwent metabolic measurements, liver ultrasonography (US) and chemical-shift magnetic resonance imaging (MRI) examinations at baseline and after 1-year nutritional intervention. A child was defined obese if her/his body mass index (BMI) was above the age- and sex-adjusted BMI Cole’s curve passing through the cut-off of 30 kg/m² at 18 years. BMI Z scores were calculated and adjusted for age and gender by using the Cole’s LMS-method and Italian reference data. Biochemistry included serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Abdominal US and chemical-shift MRI were performed according to a randomized sequence. The same radiologist performed US by a GE Logiq 9 (General Electric Healthcare Medical Systems, Milwaukee, WI, United States) using a 3.5-MHz convex array transducer. Liver echogenicity was evaluated independently on videotape by 3 radiologists unaware of the child and MRI outcomes, and a consensus was established. Another experienced radiologist, unaware of the child and US data, performed the abdominal chemical-shift MRI with a 1-t system NT-Intera (Philips Medical Systems, Best, The Netherlands) and a phased-array coil. Liver fat fraction (FF) on MRI was judged elevated when greater than 9%. A FF > 18% was considered expressing more severe cases of fatty liver according to Fishbein. A nutritional-behavioral intervention was recommended to promote a normocaloric balanced diet and active lifestyle based on the Italian guidelines for treatment of childhood obesity.

RESULTS: Compared to baseline, at the end of intervention children showed lower intakes of energy (mean ± SD: 2549 ± 1238 Kcal vs 1770 ± 622 Kcal, P < 0.0001), total fat (90 ± 47 g vs 52 ± 23 g, P < 0.0001), carbohydrates (356 ± 174 g vs 241 ± 111 g, P = 0.001), and protein (99 ± 48 g vs 75 ± 23 g, P = 0.006) intakes. Prevalence of FF ≥ 9% declined from 34.8% to 8.7% (P < 0.01), with a mean reduction of 7.8% (95%CI: 5.0-10.6). At baseline, FF was associated with liver biochemical parameters (maximum P < 0.001). At the end of the intervention association was found with AST (P = 0.017). Change of FF was associated with change in AST (P = 0.027) and ALT (P = 0.024). Rate of increased liver echogenicity declined from 45.6% to 21.7% (P < 0.0001). Liver echogenicity was associated with ALT at baseline only (P < 0.001). An age- and sex- adjusted multiple regression analysis showed that FF change was independently associated with change in serum AST (adjusted regression coefficient 0.348, P = 0.048).

CONCLUSION: The results suggest that in obese children longitudinal changes in liver fat content based on MRI may be associated with change in serum transaminases suggesting novelty in monitoring nonalcoholic fatty liver disease.

A 360-degree overview of paediatric NAFLD: recent insights

Non-alcoholic fatty liver disease (NAFLD) is a multi-faceted disorder, which ranges from simple steatosis to non-alcoholic steatohepatitis (NASH) with/without fibrosis. The effects of specific risk factors, such as obesity and sedentary lifestyle, on predisposing genetic settings eventually lead to the development of NAFLD in children. The complex interplay between genes and environment in NAFLD pathogenesis is sustained by multiple mechanisms that involve liver crosstalk with other organs and tissues, especially gut and adipose tissue. Unfortunately, natural history of paediatric NAFLD is lacking, and the etiopathogenesis is still in the process of being defined. Potential early predictors and suitable non-invasive diagnostic tools can be discovered based on the pathogenetic mechanisms and histological patterns. This will also help design novel treatments and a comprehensive and successful management strategy for patients. In this review, we discuss the recent advances made in genetics, etiopathogenesis, diagnosis, and therapeutic management of NAFLD, focusing especially on the obesity-related steatotic liver condition.

Paediatric nonalcoholic fatty liver disease

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is a multicluster disease ranging from intrahepatic simple steatosis to nonalcoholic steatohepatitis (NASH). During the last decade, NAFLD has reached epidemic proportions in overweight/obese children. In this manuscript, we review all recent advances in paediatric NAFLD.

RECENT FINDINGS

Paediatric NAFLD displays some common aspects with the adult form of disease. However, recent findings have demonstrated that regarding development of NAFLD in children, due to the absence of long-time confounding factors, it may be more appropriate to investigate genetic and pathogenetic origins of the disease. Furthermore, as the histological pattern of paediatric NAFLD is different from those observed in adults, specific diagnostic/management programmes and diagnostic scores have been recently developed. Accordingly, several studies demonstrated that both lifestyle intervention and pharmacological treatments should be adequate to the specific pattern of NAFLD in children.

SUMMARY

Results of this year's investigations further elucidated the histological features and genetic background that characterize paediatric NAFLD; the closed association of disease development with the cross-talk between different cells and organs; limitations of diagnostic tools borrowed from adult studies and the need of further clinical trial.

Pediatric non alcoholic fatty liver disease: old and new concepts on development, progression, metabolic insight and potential treatment targets

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease in children. NAFLD has emerged to be extremely prevalent, and predicted by obesity and male gender. It is defined by hepatic fat infiltration >5% hepatocytes, in the absence of other causes of liver pathology. It includes a spectrum of disease ranging from intrahepatic fat accumulation (steatosis) to various degrees of necrotic inflammation and fibrosis (non-alcoholic steatohepatatis [NASH]). NAFLD is associated, in children as in adults, with severe metabolic impairments, determining an increased risk of developing the metabolic syndrome. It can evolve to cirrhosis and hepatocellular carcinoma, with the consequent need for liver transplantation. Both genetic and environmental factors seem to be involved in the development and progression of the disease, but its physiopathology is not yet entirely clear. In view of this mounting epidemic phenomenon involving the youth, the study of NAFLD should be a priority for all health care systems. This review provides an overview of current and new clinical-histological concepts of pediatric NAFLD, going through possible implications into patho-physiolocical and therapeutic perspectives.

Sonographic hepatorenal ratio: a noninvasive method to diagnose nonalcoholic steatosis

PURPOSE

To evaluate the accuracy of the sonographic hepatorenal ratio (HRR) in the diagnosis and grading of nonalcoholic steatosis, using biopsy as the reference.

METHODS

Ultrasound (US) and liver biopsy were performed in 42 patients with nonalcoholic fatty liver disease. Forty healthy volunteers without steatosis at US and without risk factors for nonalcoholic fatty liver disease were also studied. The HRR was obtained by dividing the mean brightness level of region-of-interest pixels in hepatic parenchyma by that in renal parenchyma. Needle biopsy samples (hematoxylin-eosin stained) were classified as mild (5-33% fatty infiltration), moderate (>33-66%), or severe (>66%) steatosis. Spearman coefficient was used to evaluate the correlation between HRR and steatosis grade, analysis of variance for differences between subgroups, and receiver operating characteristic curve analysis for sensitivity and specificity.

RESULTS

Significant correlation was found between HRR and histologic steatosis (r = 0.80, p < 0.01). The HRR cutoff for predicting steatosis was ≥1.24 (sensitivity, 92.7%; specificity, 92.5%). The mean ± SD HRRs in controls and steatosis subgroups were control 1.09 ± 0.13, mild 1.46 ± 0.24, moderate 1.52 ± 0.27, severe 2.04 ± 0.3 and were significantly different from each other except between mild and moderate steatosis subgroups.

CONCLUSIONS

The HRR is a noninvasive, objective, and simple method that could be used to diagnose and grade hepatic steatosis.

Hepatic steatosis and thyroid function tests in overweight and obese children

Objectives. Associations between thyroid function and nonalcoholic fatty liver disease (NAFLD) are unknown in childhood. Thus, the aim of the present study was to investigate in 402 consecutive overweight/obese children the association between thyroid function tests and hepatic steatosis as well as metabolic variables. Methods. Hepatic steatosis was diagnosed by ultrasound after exclusion of infectious and metabolic disorders. Fasting serum samples were taken for determination of thyroid function (TSH, FT4, and FT3), along with alanine aminotransferase (ALT), lipid profile, glucose, insulin, and insulin resistance (IR). Results. Eighty-eight children (21.9%) had TSH above the normal range (>4.0 mIU/L). FT3 and FT4 were within the reference intervals in all subjects. Elevated TSH was associated with increased odds of having hepatic steatosis (OR 2.10 (95% CI, 1.22-3.60)), hepatic steatosis with elevated ALT (2.42 (95% CI, 1.29-4.51)), hypertriglyceridemia, elevated total cholesterol, and IR as well as metabolic syndrome (considered as a single clinical entity), after adjustment for age, gender, pubertal status, and body mass index-SD score (or waist circumference). Conclusions. In overweight/obese children, elevated TSH concentration is a significant predictor of hepatic steatosis and lipid and glucose dysmetabolism, independently of the degree of total and visceral obesity.

Ethnicity and elevated liver transaminases among newly diagnosed children with type 2 diabetes

BACKGROUND

To examine the influence of ethnicity on liver transaminases among adolescents with type 2 diabetes mellitus (T2DM).

METHODS

A retrospective medical chart review of 57 (30 males and 27 females) newly diagnosed patients with T2DM. Ethnicity was determined by self-report and height, weight, body mass index (BMI) and glycosylated hemoglobin (HbA1c) were obtained using standard clinical procedures. Fasting levels of alanine aminotransaminase (ALT) and aspartate aminotransferase (AST) were collected prior to the initiation of any therapy.

RESULTS

Age, gender, height, weight, BMI, and HbA1c did not differ between ethnic groups. Compared to African-Americans, Hispanics had significantly higher ALT (23.9 ± 3.4 vs. 107.8 ± 20.3, p=0.002) and AST (17.7 ± 2.5 vs. 71.1 ± 15.7, p<0.001) and were significantly more likely to have ALT values above the upper limit of normal (20% vs. 71%, p=0.005) and twice the upper limit of normal (0% vs. 39%, p=0.05) as well as AST values above the upper limit of normal (0% vs. 53%, p=0.002). No differences in ALT or AST were found between Hispanics and non-Hispanic whites or between African-Americans and non-Hispanic whites.

CONCLUSIONS

These preliminary findings suggest that Hispanic children with T2DM may be at higher risk for developing non-alcoholic fatty liver disease and indicate that a comprehensive hepatic evaluation is warranted in this population. Future studies that incorporate more precise and proximal measures of liver health are warranted in this population.

Effect of a 10-week weight loss camp on fatty liver disease and insulin sensitivity in obese Danish children

BACKGROUND AND OBJECTIVE

Childhood nonalcoholic fatty liver disease (NAFLD) associated with insulin resistance and obesity is a growing problem and increases the risk of cirrhosis, type 2 diabetes mellitus, and cardiovascular complications. We examined the effects of a 10-week "weight loss camp" residency in obese children on the prevalence and degree of NAFLD and insulin sensitivity with 12-month follow-up.

METHODS

At the camp, 117 obese white children (body mass index 28.0 ± 3.6  kg/m, age 12.1 ± 1.3 years) exercised moderately for 1 hour/day and restricted their energy intake to induce weight loss. NAFLD was diagnosed and graded using ultrasound and transaminasemia. Insulin sensitivity and glucose tolerance were assessed using homeostasis model assessment and oral glucose tolerance test. We performed anthropometric measurements and determined body composition using bioimpedance. Data were collected from 71 of 117 children at entry, after the 10 weeks at the camp, and 12 months after the camp ended.

RESULTS

The children showed an average weight loss of 7.1 ± 2.7  kg during the camp. At baseline, 43% had ultrasonographic liver steatosis, 50% elevated transaminases (>25  IU/L), and reduced insulin sensitivity. These abnormalities were mutually related and improved significantly during the camp (P ≤ 0.05). Liver fat improvement was sustained at 12 months. At the 12-month follow-up, 17 of 71 (24%) children maintained the body weight.

CONCLUSIONS

This short-term diet and exercise program induced weight loss, markedly improved all aspects of the threatening condition of NAFLD, and reduced insulin sensitivity in childhood obesity; 24% of the children maintained weight loss at least until the 12-month follow-up.

Pediatric nonalcoholic fatty liver disease: a multidisciplinary approach

Nonalcoholic fatty liver disease (NAFLD) is a multifactorial condition, ranging from simple steatosis to nonalcoholic steatohepatitis (NASH) with or without fibrosis. NAFLD affects both adults and children who present with particular risk factors, including obesity, sedentary lifestyle and/or a predisposing genetic background. The escalation of the prevalence of NAFLD in children worldwide is a worrying phenomenon because this disease is closely associated with the development of both cirrhosis and cardiometabolic syndrome in adulthood. The etiopathogenesis of primary NAFLD in children is unknown; however, considerable knowledge about the mechanisms of liver damage that occur during disease progression has been gathered over the past 30 years. Understanding the pathogenetic mechanisms, together with the histological pattern, provide the basis to characterize potential early predictors of the disease, suitable noninvasive diagnostic tools and design novel specific treatments and possible management strategies. Despite a few clinical trials on the use of antioxidants combined with lifestyle intervention for NAFLD that showed encouraging results, to date, no treatment guidelines exist for children with NAFLD. In this Review, we provide an overview of current concepts in epidemiology, histological features, etiopathogenesis, diagnosis and treatment of NAFLD in children and adolescents.

Thyroid function in childhood obesity and metabolic comorbidity

Childhood obesity is a worldwide health problem and its prevalence is increasing steadily and dramatically all over the world. Obese subjects have a much greater likelihood than normal-weight children of acquiring dyslipidemia, elevated blood pressure, and impaired glucose metabolism, which significantly increase their risk of cardiovascular and metabolic diseases. Elevated TSH concentrations in association with normal or slightly elevated free T4 and/or free T3 levels have been consistently found in obese subjects, but the mechanisms underlying these thyroid hormonal changes are still unclear. Whether higher TSH in childhood obesity is adaptive, increasing metabolic rate in an attempt to reduce further weight gain, or indicates subclinical hypothyroidism or resistance and thereby contributes to lipid and/or glucose dysmetabolism, remains controversial. This review highlights current evidence on thyroid involvement in obese children and discusses the current controversy regarding the relationship between thyroid hormonal derangements and obesity-related metabolic changes (hypertension, dyslipidemia, hyperglycemia and insulin resistance, nonalcoholic fatty liver disease) in such population. Moreover, the possible mechanisms linking thyroid dysfunction and pediatric obesity are reviewed. Finally, the potential role of lifestyle intervention as well as of therapy with thyroid hormone in the treatment of thyroid abnormalities in childhood obesity is discussed.

T1-weighted dual-echo MRI for fat quantification in pediatric nonalcoholic fatty liver disease

AIM: To determine in obese children with nonalcoholic fatty liver disease (NAFLD) the accuracy of magnetic resonance imaging (MRI) in assessing liver fat concentration.

METHODS: A case-control study was performed. Cases were 25 obese children with biopsy-proven NAFLD. Controls were 25 obese children matched for age and gender, without NAFLD at ultrasonography and with normal levels of aminotransferases and insulin. Hepatic fat fraction (HFF) by MRI was obtained using a modification of the Dixon method.

RESULTS: HFF ranged from 2% to 44% [mean, 19.0% (95% CI, 15.1-27.4)] in children with NAFLD, while in the controls this value ranged from 0.08% to 4.69% [2.0% (1.3-2.5), P < 0.0001]. HFF was highly correlated with histological steatosis (r = 0.883, P < 0.0001) in the NAFLD children. According to the histological grade of steatosis, the mean HFF was 8.7% (95% CI, 6.0-11.6) for mild, 21.6% (15.3-27.0) for moderate, and 39.7% (34.4-45.0) for severe fatty liver infiltration. With a cutoff of 4.85%, HFF had a sensitivity of 95.8% for the diagnosis of histological steatosis ≥ 5%. All control children had HFF lower than 4.85%; thus, the specificity was 100%. After 12 mo, children with weight loss displayed a significant decrease in HFF.

CONCLUSION: MRI is an accurate methodology for liver fat quantification in pediatric NAFLD.

Management of metabolic syndrome in children and adolescents

Concomitantly with the increasing prevalence of childhood obesity, the prevalence of metabolic syndrome (MS) is rising among children and adolescents, leading to fears for future epidemics of type 2 diabetes mellitus and cardiovascular disease in the young. This makes the accurate identification and the appropriate treatment of children and adolescents with MS an important priority for health care systems. This review will focus on the management of each component of MS, including the nonalcoholic fatty liver disease (NAFLD), which is currently considered as the hepatic component of the syndrome. The most relevant target of treatment of MS in children and adolescents is the abdominal obesity. To this end, we will discuss the efficacy of dietary approaches, possibly coupled with regular physical activity, on eliciting visceral fat reduction. We will also highlight several aspects of the treatment of the high triglyceride/low high-density lipoprotein cholesterol phenotype, including the use of non-pharmacological measures, and indications for instituting drug therapies. Part of this review will address treatment of glucose abnormalities, including the benefits of lifestyle modification alone, and the potential adjunctive role of hypoglycemic drugs. The treatment of hypertension in children with MS also requires a multifaceted approach and the available data of this topic will be examined. The remainder of this review will address treatment to reverse NAFLD and prevent progression to end-stage disease.

[Fatty liver and its clinical management in obese adolescents]

Liver steatosis, also called non-alcoholic fatty liver, is characterized by a pathological fat accumulation in the liver, leading to liver damage in the form of inflammation and fibrosis. These histological features are similar to those in alcoholic hepatitis. Obesity is known to be the most common cause of simple steatosis in the preadolescent and adolescent population with a consequent serious health risk. The aim of this study was to provide an update on the concepts, pathophysiology and clinical management of hepatic steatosis secondary to obesity at an early age.