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Background: The relations between hepatic steatosis and histological features of hepatocyte injury in children with nonalcoholic fatty liver disease have yet to be examined. The aims of the present study were to establish associations between steatosis amount, type, and distribution in a well-characterized group of children with biopsy-proven nonalcoholic fatty liver disease (NAFLD). Patients and Methods: One hundred eight children with NAFLD seen in 5 centers were studied. Clinical and laboratory data were collected. Hematoxylin-eosin and Masson trichrome stains were evaluated by 2 expert liver pathologists. Steatosis grade (0–3), type (macrovesicular, microvesicular, or mixed), and zone (1, 3, azonal, or panacinar) were determined. The NAFLD activity score and fibrosis stage were determined. Results: Median patient age was 12 years and median body mass index was 31 kg/m2. Fibrosis was present in 87%. The median NAFLD activity score was 4. Mild, moderate, and severe steatosis were present in 42%, 34%, and 24% of biopsies, respectively. Macrovesicular steatosis was present in 81% and mixed steatosis was present in 19%. Panacinar distribution of steatosis was most frequent (40%), followed by azonal (27%). Steatosis grade positively correlated with portal inflammation (P = 0.018). Azonal distribution positively correlated with presence of hepatocyte ballooning (P = 0.03). Biopsies with mixed steatosis were approximately 20 times more likely to have megamitochondria than those with macrovesicular steatosis alone (95% confidence interval 2.3–204.9). There was no relation between steatosis amount, type, or distribution to fibrosis stage. Conclusions: Specific histological patterns of steatosis in children are associated with histological markers of steatohepatitis. Ballooning and portal inflammation correlated well with features of steatosis.

Nonalcoholic fatty liver disease is the most common form of chronic liver disease in both children and adults.1,2 It is estimated that nonalcoholic fatty liver disease (NAFLD) affects about 20% to 30% of adults and 10% of children in the United States.3,4 NAFLD represents a wide spectrum of conditions ranging from fatty liver to nonalcoholic steatohepatitis (NASH) to advanced fibrosis and cirrhosis.5 Steatosis without significant liver cell injury or fibrosis is the most common form of NAFLD in both adults and children.1,2 Studies in the adult population have variably suggested that steatosis is a benign nonprogressive condition, and NASH is recognized as a potentially serious condition with significant risk of morbidity and mortality.6-9 Liver biopsy remains the standard for establishing the diagnosis of NASH.10,11 The histological criteria for NASH in the adult population have evolved over the last two decades since the seminal publication of Ludwig et al.12 The principal histological features of adult NASH include the presence of macrovesicular steatosis (characterized by a single or a few large droplets of fat and displacement of the nucleus), ballooning degeneration of hepatocytes, and a mixed lobular inflammation with or without a degree of portal inflammation.10,11 Other features that are commonly present include zone 3 perisinusoidal–pericellular fibrosis; Mallory-Denk bodies (Mallory's hyaline); megamitochondria; acidophil bodies; and iron in hepatocytes, sinusoidal lining cells, or both. A growing body of evidence suggests that children with NASH frequently show histopathological features that differ from those of adults characterized mainly by lack of zone 3 accentuation and the predominance of portal-based inflammation and fibrosis.13 Schwimmer et al.14 identified this recently as type 2 NASH, with the aforementioned features in adults as type 1 NASH. The prevalence of this pattern in a wide range of pediatric cases as well as other other histopathological lesions and their relevance and prognostic significance in children with NAFLD remains to be determined. Thus, we conducted this study of biopsies and clinical information from five North American centers to document the histological features of pediatric NAFLD, determine the frequency and prognostic value of these features, and perform clinico-pathological correlations.

Nonalcoholic fatty liver disease (NAFLD) has emerged as a growing public health problem worldwide. NAFLD represents a wide spectrum of conditions ranging from fatty liver, that in general follows a benign nonprogressive clinical course, to nonalcoholic steatohepatitis (NASH), a serious form of NAFLD, that may progress to cirrhosis and end-stage liver disease. The mechanisms responsible for NAFLD development and disease progression remain incompletely understood, but are of great clinical interest as current therapies are limited. Future therapies will be predicted based upon the understanding of its pathogenesis. This review focuses on the growing evidence from both experimental and human studies suggesting a central role of cytokines in the pathogenesis of NAFLD. We review the role of cytokines as key regulators of insulin sensitivity and hepatic lipid overloading, liver injury and inflammation, and fibrosis and cirrhosis, with an emphasis on potential therapeutic implications.

Hepatitis B virus (HBV) reactivation has been described in patients treated with infliximab for inflammatory bowel disease (IBD). This has resulted in a "black box" warning. Although universal vaccination against hepatitis B was implemented in the United States in 1991, up to 10% of vaccine recipients fail to respond with adequate anti-hepatitis B surface antibodies (anti-HBs) levels after a primary series of vaccinations. In addition, anti-HBs levels are expected to decline with time. The objectives of this study were to determine HBV immunity in children with IBD on infliximab therapy and to determine response to a booster dose of the HBV vaccine in patients who were found to be non-immune.This was a prospective cross-sectional, single-center study that included 100 pediatric IBD patients on infliximab. Serologic specimens were tested for hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc), and anti-HBs. Patients with an anti-HBs level ≥10 mIU/ml were considered to be immune. One booster dose was given to non-immune patients and a serum sample was collected after 4 weeks to assess the presence of anamnestic response (anti-HBs level ≥10 mIU/ml after booster).The mean age of the patients was 17.9 (±4.0) years. None of the patients were positive for HBsAg or anti-HBc. In all, 87 patients were vaccinated against HBV and 49/87 (56%) had immunity to HBV as defined by anti-HBs level ≥10 mIU/ml. The mean concentration of anti-HBs levels in immune patients was 295.6 (±350.6) mIU/ml. Older age, lower albumin levels, and the presence of pancolitis were associated with the absence of protective antibodies; however, infliximab dose, frequency, duration, and the concurrent use of immunomodulators were not significantly different between immune and non-immune patients. Thirty-four patients received booster immunization and 26/34 (76%) had an anamnestic response. Interestingly, non-responders were given infliximab with higher frequency (every 5.9 ± 1.2 weeks vs. every 7.1 ± 1.8 weeks, P=0.01). Overall, 75/87 (86%) of previously immunized patients were considered immune against HBV infection.In pediatric IBD patients seen at a large, urban tertiary care facility in the United States, a significant minority (13%) have not been vaccinated against HBV. Nearly one-half of all patients (and 44% of previously vaccinated patients) did not have protective anti-HBs levels. Moreover, of those previously vaccinated, a significant minority (14%) appear at risk for HBV because protective anti-HBs levels were absent and could not be elicited through booster immunization. Given the high risk for severe HBV infection in this group, efforts should be made to screen for HBV immunity at the time of IBD diagnosis. Booster immunization should be considered in patients without protective antibodies.

The diagnostic accuracy of hepatic ultrasonography (US) for detection and grading of hepatic steatosis in children with suspected nonalcoholic fatty liver disease (NAFLD) remains poorly characterized. The aim of this study was to prospectively evaluate the clinical utility of ultrasonographic quantification of hepatic steatosis.Our cohort consisted of 208 consecutive pediatric patients with biopsy-proven NAFLD. Hepatic US was performed within 1 month of the liver biopsy procedure. Steatosis identified by US was scored using a 0 to 3 scale based on echogenicity and visualization of vasculature, parenchyma, and diaphragm, and compared to histological features based on Brunt's classification.The median age at time of first visit was 10.8 years and 64% were boys. Sixty-nine percent had moderate to severe steatosis on histology. Ultrasonographic steatosis score (USS) had an excellent correlation with histological grade of steatosis (with a Spearman's coefficient of 0.80). The area under the receiver operating characteristic curve for ultrasonographic detection of moderate-to-severe steatosis was 0.87. The USS did not correlate significantly with inflammatory activity or fibrosis stage; however, there was significant correlation with the NAFLD activity score (NAS), albeit this was in large part the result of the strong correlation with the steatosis component of NAS. Serum alanine transaminase and aspartate transaminase were not associated with histological grade of steatosis and showed no correlation with USS.Our results, which represent the largest prospective pediatric study evaluating the role of hepatic US in children with biopsy-proven NAFLD, demonstrate the utility of this technique for noninvasive diagnosis and estimation of hepatic steatosis in children.

Nonalcoholic fatty liver disease is now regarded as the most common form of chronic liver disease in adults and children. The close association between nonalcoholic fatty liver disease (NAFLD) and the metabolic syndrome has been extensively described. Moreover, a growing body of evidence suggest that NAFLD by itself confers a substantial cardiovascular risk independent of the other components of the metabolic syndrome. Given the significant potential for morbidity and mortality in these patients, and the large proportion of both pediatric and adult population affected, it is important that we clearly define the overall risk, identify early predictors for cardiovascular disease progression, and establish management strategies. In this article, we will focus on current data linking NAFLD and the severity of liver damage present in children with cardiovascular risk.

The prevalence of obesity worldwide has dramatically increased during the last three decades. With obesity comes a variety of adverse health outcomes which are grouped under the umbrella of metabolic syndrome. The liver in particular seems to be significantly impacted by fat deposition in the presence of obesity. In this article we discuss several liver conditions which are directly affected by overweight and obese status, including non-alcoholic fatty liver disease, chronic infection with hepatitis C virus and post-liver transplant status. The deleterious effects of obesity on liver disease and overall health can be significantly impacted by a culture that fosters sustained nutritional improvement and regular physical activity. Here we summarize the current evidence supporting non-pharmacological, lifestyle interventions that lead to weight reduction, improved physical activity and better nutrition as part of the management and treatment of these liver conditions.

Pathological increases in cell death in the liver as well as in peripheral tissues has emerged as an important mechanism involved in the development and progression of nonalcoholic fatty liver disease (NAFLD). An increase in hepatocyte cell death by apoptosis is typically present in patients with NAFLD and in experimental models of steatohepatitis, while an increase in adipocyte cell death in visceral adipose tissue may be an important mechanism triggering insulin resistance and hepatic steatosis. The two fundamental pathways of apoptosis, the extrinsic (death receptor-mediated) and intrinsic (organelle-initiated) pathways, are both involved. This article summarizes the current knowledge related to the distinct molecular and biochemical pathways of cell death involved in NAFLD pathogenesis. In particular, it will highlight the efforts for the development of both novel diagnostic and therapeutic strategies based on this knowledge.

Nonalcoholic fatty liver disease (NAFLD) encompasses diseases from simple steatosis, to steatohepatitis, to fibrosis, and cirrhosis. The pediatric NAFLD fibrosis index (PNFI) and the enhanced liver fibrosis (ELF) test are potential noninvasive markers for fibrosis. We prospectively evaluated the performance of PNFI and ELF in assessing fibrosis in children with biopsy-proven NAFLD.We analyzed 111 consecutive children with NAFLD. The stage of fibrosis was scored according to the Nonalcoholic Steatohepatitis Clinical Research Network. PNFI was calculated based on age, waist circumference, and levels of triglycerides. The ELF test was used to determine levels of hyaluronic acid, the amino-terminal propeptide of type III collagen, and tissue inhibitor of metalloproteinase-1.Some degree of fibrosis was detected in 68.5% of patients (62 had stage 1, 5 had stage 2, and 9 had stage 3). PNFI and ELF test values was higher among patients with fibrosis (P.001). The area under the receiver operating characteristic (ROC) curve for predicting fibrosis using the PNFI and ELF test was 0.761 and 0.924, respectively. The best performance was obtained by combining PNFI and ELF test with (area under the receiver operating characteristic curve = 0.944). The combined results from the PNFI and ELF test predicted the presence or absence of fibrosis in 86.4% of children with NAFLD.In children with NAFLD, the combined results from the PNFI and ELF test can accurately assess the presence of liver fibrosis and identify patients that should be evaluated by liver biopsy.