Nonalcoholic fatty liver disease in the pediatric population: a review

Vegetable Oil-Peroxidation Product 'Hydroxynonenal' Causes Hepatocyte Injury and Steatosis via Hsp70.1 and BHMT Disorders in the Monkey Liver

Hsp70.1 has a dual function as a chaperone protein and lysosomal stabilizer. In 2009, we reported that calpain-mediated cleavage of carbonylated Hsp70.1 causes neuronal death by inducing lysosomal rupture in the hippocampal CA1 neurons of monkeys after transient brain ischemia. Recently, we also reported that consecutive injections of the vegetable oil-peroxidation product 'hydroxynonenal' induce hepatocyte death via a similar cascade in monkeys. As Hsp70.1 is also related to fatty acid β-oxidation in the liver, its deficiency causes fat accumulation. The genetic deletion of betaine-homocysteine S-methyltransferase (BHMT) was reported to perturb choline metabolism, inducing a decrease in phosphatidylcholine and resulting in hepatic steatosis. Here, focusing on Hsp70.1 and BHMT disorders, we studied the mechanisms of hepatocyte degeneration and steatosis. Monkey liver tissues with and without hydroxynonenal injections were compared using proteomics, immunoblotting, immunohistochemical, and electron microscopy-based analyses. Western blotting showed that neither Hsp70.1 nor BHMT were upregulated, but an increased cleavage was observed in both. Proteomics showed a marked downregulation of Hsp70.1, albeit a two-fold increase in the carbonylated BHMT. Hsp70.1 carbonylation was negligible, in contrast to the ischemic hippocampus, which was associated with ~10-fold increments. Although histologically, the control liver showed very little lipid deposition, numerous tiny lipid droplets were seen within and around the degenerating/dying hepatocytes in monkeys after the hydroxynonenal injections. Electron microscopy showed permeabilization/rupture of lysosomal membranes, dissolution of the mitochondria and rough ER membranes, and proliferation of abnormal peroxisomes. It is probable that the disruption of the rough ER caused impaired synthesis of the Hsp70.1 and BHMT proteins, while impairment of the mitochondria and peroxisomes contributed to the sustained generation of reactive oxygen species. In addition, hydroxynonenal-induced disorders facilitated degeneration and steatosis in the hepatocytes.

Regulatory Effects and Molecular Mechanisms of Tea and Its Active Compounds on Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disease, is a multifactorial disease resulting from the interaction between environment, genetic background, and metabolic stress. Most treatments for NAFLD include dietary intervention and exercise show limited efficacy due to the complex mechanisms involved in NAFLD. Meanwhile, drug therapy is accompanied by serious side effects. The development of high-efficiency natural supplements is a sustainable strategy for the prevention and treatment of NAFLD. As the second most consumed beverage, tea has health benefits that have been widely recognized. Nevertheless, the intervention of tea active compounds in NAFLD has received limited attention. Tea contains abundant bioactive compounds with potential effects on NAFLD, such as catechins, flavonoids, theanine, tea pigments, and tea polysaccharides. We reviewed the intrinsic and environmental factors and pathogenic mechanisms that affect the occurrence and development of NAFLD, and summarized the influences of exercise, drugs, diet, and tea drinking on NAFLD. On this basis, we further analyzed the potential effects and molecular regulatory mechanisms of tea active compounds on NAFLD and proposed future development directions. This review hopes to provide novel insights into the development and application of tea active compounds in the prevention and treatment of NAFLD.

Factors associated with the perception of parents and children regarding obesity-related terminology used by healthcare professionals in a sample of Korean children and adolescents with obesity

OBJECTIVE

This study aimed to compare how children with overweight or obesity and their parents perceive the obesity-related terms used by healthcare professionals and investigate the factors associated with these perceptions.

METHODS

Children and adolescents aged 8-16 years with overweight or obesity (n = 192) and their parents participated in the cross-sectional study by responding to a 5-point Likert-scale questionnaire on 10 obesity-related terms, including "chubby," "weight problem," "weight," "overweight," "BMI," "obese," "heavy," "fleshy," "fat," and "severely obese."

RESULTS

For both children and parents, "chubby" was the most desirable term (mean ± standard deviation: 3.50 ± 1.12 and 2.95 ± 0.83, respectively), and "severely obese" was the least acceptable term (2.83 ± 1.17 and 2.02 ± 1.02, respectively). Although the parents preferred all the terms less than the children did (p < 0.001), "weight problem" was considered most motivating for a child to lose weight (3.93 ± 0.94). Among children, older age and a larger self-perceived body size were associated with a more positive response towards obesity-related terms, whereas having internalized or externalized problems were negatively associated with these terms. Parents with a history of cardiovascular disease considered "severely obese" (β = -0.419, [95% CI: -0.739, -0.099]) and "fat" (β = -0.457, [95% CI: -0.750, -0.164]) less desirable.

CONCLUSIONS

Children and adolescents had a higher preference for obesity-related terms than their parents and preferred that healthcare professionals use euphemistic terms such as "chubby," or neutral terms such as "weight problem." Children with larger self-perceived body sizes or older age had a higher preference for obesity-related words. The terms used by healthcare professionals to describe excess weight must be motivating and respectful for all family members participating in the treatment.

Trends and Disparities in Pediatric Nonalcoholic Fatty Liver Disease-Associated Hospitalizations in the United States

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) represents a spectrum of disease characterized by accumulation of fat in the liver and is associated with co-morbidities linked to metabolic syndrome. The prevalence of NAFLD in children has increased in the United States over time and with marked racial differences observed in geographically limited studies. This study aims to provide a current, nation-wide analysis of temporal trends of pediatric NAFLD-related hospitalizations and associated co-morbidities as well as assess for racial/ethnic disparities.

METHODS

A cross-sectional study was conducted using the National Inpatient Sample (NIS) from 2004 to 2018 and included NAFLD-associated hospitalizations of children ages 0-17 years of age based on ICD-9/10 diagnosis codes. Rates and patient characteristics analyzed via descriptive statistics and associations via survey logistic regression. Temporal trends assessed via joinpoint regression.

RESULTS

There was an overall increase in pediatric NAFLD-associated hospitalizations with an average annual percent change (AAPC) of 6.6 with highest rates among Hispanic patients (AAPC = 11.1) compared to NH-White (AAPC = 4.1) and NH-Black (AAPC = 2.1). Analysis of race/ethnicity and NAFLD hospitalization showed an increased association in Hispanic patients (odds ratio [OR] = 1.64, 95% confidence interval [CI] = 1.51-1.77) and a decreased association in non-Hispanic (NH)-Black patients (OR = 0.49, 95% CI = 0.45-0.54) when compared to NH-White patients.

CONCLUSION

Utilizing a nation-wide database we demonstrated significant increases in NAFLD-associated hospitalizations with highest prevalence and rates seen in Hispanic patients. In addition, sex and comorbidities showed notable correlation to these hospitalization rates displaying the need for further studies on these relationships and highlights the potential for interventions aimed at high-risk groups.

Prevalence and Clinical Significance of Autoantibodies in Children with Overweight and Obesity with Nonalcoholic Fatty Liver Disease

OBJECTIVES

To evaluate the prevalence and clinical significance of autoantibodies in children with overweight and obesity with nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH) compared with those with autoimmune liver disease (ALD).

STUDY DESIGN

This was a retrospective, cross-sectional study of children with a biopsy-proven diagnosis of NAFL, NASH, autoimmune hepatitis (AIH), or primary sclerosing cholangitis (PSC) and a body mass index (BMI) >85th percentile treated between 2007 and 2016.

RESULTS

A total of 181 patients were identified, including 31 (17%) with NAFL, 121 (67%) with NASH, 12 (6.6%) with ALD (AIH, PSC, or overlap), and 17 (9.4%) with combined ALD and NAFLD. Antinuclear antibody (ANA), anti-actin antibody, and anti-liver kidney microsomal (LKM) antibody were positive in 16.1%, 13.8%, and 0%, respectively, of the patients with NAFL and in 32.8%, 15.5%, and 0%, respectively, of those with NASH. Total immunoglobulin G (IgG) was elevated in 27.3% of the patients with NAFL and in 47.7% of those with NASH, but in 100% of those with ALD. The positive predictive value of LKM was 100% for ALD but only 29% for ANA and 46% for anti-actin antibody.

CONCLUSIONS

False-positive rates of autoantibodies were higher in pediatric patients with overweight and obesity with NAFLD compared with the general adult population. Positive LKM had the highest specificity and positive predictive value, and elevated IgG level had the highest sensitivity for ALD. The presence of autoantibodies does not signal more severe NAFLD in children. BMI >98th percentile seems to be an important breakpoint above which ALD is less likely.

The promising role of CCL2 as a noninvasive marker for nonalcoholic steatohepatitis diagnosis in Egyptian populations

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a common liver problem, including both nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). In this study, we investigated the role of CCL2 and IL6 as a noninvasive tool for the diagnosis of NASH in clinical practice and to establish criteria for discrimination NASH from NAFL in Egyptian populations with NAFLD.

METHOD

In addition to 30 healthy controls, serum samples from 66 NAFLD patients histologically diagnosed by biopsy (32 NAFL and 34 NASH) were analyzed for serum IL6, CCL2, liver biomarkers, complete blood count and lipid profile. Serum IL6 or CCL2 levels were tested for correlation with the NASH activity score (NAS score).

RESULT

Both IL6 and CCL2 were significantly upregulated in NASH patients compared with NAFL patients or control. Serum CCL2 was significantly correlated with the degree of hepatocytes ballooning (the diagnostic endpoint for NASH) without any significant correlation with steatosis or lobular inflammation. Serum IL6 was not correlated with the NAS score. The ROC curve analysis of CCL2 for NASH diagnosis revealed an area under curve (AUROC) of 0.959 at cutoff ≥227 pg/ml. While IL6 revealed an (AUROC) of 0.790.

CONCLUSION

Serum CCL2 but not IL6 is a promising noninvasive tool for NASH diagnosis and CCL2 can provide a reliable, validated scoring system to discriminate NAFL from NASH in the Egyptian population confirming the role of CCL2 in NASH pathogenesis. These findings will aid in the development of innovative NASH treatment strategies in Egypt and improve the quality of clinical care.

A Nomogram for Predicting Non-Alcoholic Fatty Liver Disease in Obese Children

PURPOSE

Non-alcoholic fatty liver disease (NAFLD) ranges in severity from simple steatosis to steatohepatitis. Early detection of NAFLD is important for preventing the disease from progressing to become an irreversible end-stage liver disease. We developed a nomogram that allows for non-invasive screening for NAFLD in obese children.

METHODS

Anthropometric and laboratory data of 180 patients from our pediatric obesity clinic were collected. Diagnoses of NAFLD were based on abdominal ultrasonographic findings. The nomogram was constructed using predictors from a multivariate analysis of NAFLD risk factors.

RESULTS

The subjects were divided into non-NAFLD (n=67) and NAFLD groups (n=113). Factors, including sex, body mass index, abdominal circumference, blood pressure, insulin resistance, and levels of aspartate aminotransferase, alanine aminotransferase (ALT), γ-glutamyl transpeptidase (γGT), uric acid, triglycerides, and insulin, were significantly different between the two groups (all p<0.05) as determined using homeostatis model assessment of insulin resistance (HOMA-IR). In our multivariate logistic regression analysis, elevated serum ALT, γGT, and triglyceride levels were significantly related to NAFLD development. The nomogram was established using γGT, uric acid, triglycerides, HOMA-IR, and ALT as predictors of NAFLD probability.

CONCLUSION

The newly developed nomogram may help predict NAFLD risk in obese children. The nomogram may also allow for early NAFLD diagnosis without the need for invasive liver biopsy or expensive liver imaging, and may also allow clinicians to intervene early to prevent the progression of NAFLD to become a more advanced liver disease.

Retinoic acid induced 16 deficiency exacerbates high-fat diet-induced steatohepatitis in mice

Non-alcoholic fatty liver disease (NAFLD) associated with obesity may progress to non-alcoholic steatohepatitis, cirrhosis and hepatocellular carcinoma (HCC). Retinoic acid induced 16 (RAI16) plays an important role in cell apoptosis and is also a potential marker for HCC. Here we aimed to test the effect of RAI16 deficiency on liver pathology in high-fat diet (HFD) fed mice. Wild type (WT) and RAI16 knockout (RAI16-/-) C57BL/6 mice were fed with HFD or chow for up to 12 months. With consumption of HFD diet, RAI16-/- mice on HFD developed much more excess fatty liver within 4 months than WT mice on HFD. The expressions of fatty acid synthesis associated molecules Ppar-γ, Srebp-1c and Fas were further increased in RAI16-/- mice compared with WT mice on HFD. Macrophage infiltration related molecules Mcp-1 and F4/80 and pro-inflammatory factor Lcn2 were significantly increased in RAI16-/- mice compared with WT mice on HFD. Conclusively, RAI16 deficiency exacerbated HFD-induced liver injury, associated with increased inflammation. These findings indicate that RAI16 plays an important role in HFD-induced liver pathology and might be considered as a target for treatment of NAFLD. SIGNIFICANCE: 1. RAI16-/- mice on HFD developed much more excess fatty liver. 2. RAI16-/- mice showed more macrophage infiltration and proinflammation.

Long-Term Feeding of Soy Protein Attenuates Choline Deficient-Induced Adverse Effects in Wild Type Mice and Prohibitin 1 Deficient Mice Response More Sensitively

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, however the exact cause of NAFLD remains unknown. Methionine, an essential amino acid, is the first limiting amino acid of soy protein, and its deficiency is suggested to cause hepatocyte damage and NAFLD. The objective of this study is to examine the changes in NAFLD susceptibility with soy protein consumption and deterioration due to prohibitin 1 (PHB1) deficiency, an important protein in hepatic mitochondrial function. In this study, liver-specific phb1 +/- mice and wild-type mice were fed a normal diet, choline-deficient diet (CDD), or soy protein diet without choline (SPD) for 16 weeks. Using hematoxylin and eosin staining, we showed that SPD attenuates symptoms of hepatocyte damage and lipid accumulation induced by CDD in mouse liver. The liver damage in mice fed the SPD was alleviated by decreasing lipogenic markers and by increasing anti-inflammatory markers. Furthermore, mRNA expression of genes involved in hepatic methionine metabolism was significantly lower in liver-specific phb1 +/- mice fed with a SPD compared with wild-type mice fed with a SPD. These data suggest a CDD can cause non-alcohol related liver damage, which can be attenuated by a SPD in wild-type mice. These phenomena were not observed in liver-specific phb1 +/- mice. It may therefore be concluded that SPD attenuates CDD-induced liver damage in wild-type mice, and that PHB1 deficiency blocks the beneficial effects of SPD against CDD-induced liver damage.

Bisphenol a increases risk for presumed non-alcoholic fatty liver disease in Hispanic adolescents in NHANES 2003-2010

BACKGROUND

Bisphenol-A (BPA) is a ubiquitous chemical and recognized endocrine disruptor associated with obesity and related disorders. We explored the association between BPA levels and suspected non-alcoholic fatty liver disease (NAFLD).

METHODS

Unweighted analyses were used to study the relationship between urinary BPA levels and suspected NAFLD (alanine aminotransferase (ALT). > 30 U/L, body mass index (BMI) Z-score > 1.064 and evidence of insulin resistance) using National Health and Nutrition Examination Survey (NHANES) data (2003-2010) on 12-19 year olds. Unweighted and weighted analyses were used to evaluate the risk with only elevated ALT.

RESULTS

We included 944 adolescents with urinary BPA and fasting laboratory tests from a total of 7168 adolescents. Risk of suspected NAFLD was increased in the second quartile of BPA levels (1.4-2.7 ng/mL) when compared to the first (< 1.4 ng/mL) (Odds Ratio (OR) 4.23, 95% Confidence Interval (CI) 1.44-12.41). The ORs for the third and second quartiles were positive but did not reach statistical significance. The association was stronger in Hispanics (n = 344) with BPA levels in the second (OR 6.12, 95% C.I. 1.62-23.15) quartile and when limiting the analyses to overweight/obese adolescents (n = 332), in the second (OR 5.56, 95% C.I. 1.28-24.06) and fourth BPA quartiles (OR 6.85, 95% C.I. 1.02-46.22) compared to the first quartile. BPA levels were not associated with ALT elevation.

CONCLUSIONS

The risk of suspected NAFLD is increased in participants in higher quartiles of BPA exposure, particularly in those of Hispanic ethnicity. Further studies are required to fully understand the potential role of BPA in non-alcoholic fatty liver disease.

Effects of Exercise Training Alone on Depot-Specific Body Fat Stores in Youth: Review of Recent Literature

The prevalence of childhood obesity has increased at an alarming rate. The increased obesity rate in pediatrics parallels the increased risks for developing metabolic abnormalities, such as insulin resistance, type 2 diabetes, and nonalcoholic fatty liver disease. In particular, the strong relationship between obesity and such health consequences is well explained by the excessive accumulation of depot-specific body adiposity, such as visceral adipose tissue, intrahepatic lipid content, intermuscular adipose tissue, and/or intramyocellular lipid content. Limited evidence suggests that both aerobic and resistance exercise alone, independent of weight loss, can be an effective therapeutic strategy for improving risk markers of metabolic abnormalities as well as inducing positive changes in depot-specific body adiposity in obese children and adolescents. However, the independent role of exercise alone (without calorie restriction) in body fat distribution is still unclear, and the results are less conclusive in pediatrics. In this brief review, the effects of aerobic and resistance exercise on depot-specific body adiposity changes in children and adolescents are discussed.

Visceral fat is associated with the racial differences in liver fat between black and white adolescent boys with obesity

OBJECTIVE

We examined whether racial differences in liver fat are associated with the differences in abdominal fat distribution or cardiorespiratory fitness (CRF).

METHODS

Participants included 57 black and white obese boys (12-18 years). Total and abdominal fat was measured by dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging, respectively. CRF was measured using a maximal graded treadmill test with the use of standard open-circuit spirometry techniques until volitional fatigue. Liver fat was measured using a 3T proton magnetic resonance spectroscopy. Fatty liver was defined as having liver fat ≥5%.

RESULTS

In the sample, 16.1% of black boys and 30.8% of white boys had fatty liver. Liver fat was associated (P ≤ .05) with body mass index (BMI) percentile (r = 0.28), total fat (r = 0.31), waist circumference (r = 0.38), visceral fat (r = 0.62), abdominal subcutaneous adipose tissue (r = 0.30), and CRF (r = -0.27) adjusting for age and race. White boys had greater liver fat than black boys with adjustment for age and differences in BMI percentile or CRF, but not with waist circumference or visceral fat (P > .05). In a model with age, ethnicity, total body fat, fat-free mass, visceral fat, abdominal subcutaneous fat, and CRF, visceral fat was the only factor to be independently associated with increased odds of having fatty liver (OR = 1.12; 95% CI: 1.04-1.21; P = .003).

CONCLUSION

The racial disparities in liver fat between obese black vs white adolescents are explained, in part, by differences in visceral fat.

Associations between arterial structure and function and serum levels of liver enzymes in obese adolescents

AIM

To determine the structural and functional alterations of systemic arteries in obese adolescents and their relationships with adiposity, metabolic and lipid profile, and serum liver enzyme levels.

METHODS

Carotid intima-media thickness (IMT), carotid stiffness index, and brachial-ankle pulse wave velocity (baPWV) were measured in 56 obese adolescents and 58 lean controls. Obese adolescents had additional liver ultrasound and determination of fasting blood indices of glucose metabolism and lipid profile, and serum levels of liver enzymes.

RESULTS

Carotid IMT (P < 0.0001), carotid stiffness index (P < 0.0001) and baPWV (P = 0.001) were significantly greater in obese than control subjects. Thirty-seven (66%) obese subjects had fatty liver changes and their aspartate aminotransferase, alanine aminotransferase (ALT), alkaline phosphatase, and gamma-glutamyl transferase levels were significantly higher than those without (all P < 0.05). Univariate analyses showed positive correlations between serum ALT (r = 0.29, P = 0.03) and alkaline phosphatase (r = 0.28, P = 0.04) levels and carotid IMT, aspartate aminotransferase level and carotid stiffness (r = 0.41, P = 0.002), and gamma-glutamyl transferase level and baPWV (r = 0.34, P = 0.02) in obese subjects. Multivariate linear regression revealed serum ALT level (β = 0.02, P = 0.006) as an independent correlate of carotid stiffness.

CONCLUSION

Obese adolescents have increased carotid IMT and stiffness, which are associated positively with serum liver enzyme levels.

Development of Distinct Body Mass Index Trajectories Among Children Before Age 5 Years: A Population-Based Study

The prevalence of childhood obesity has increased over the past 3 decades. This study was designed to understand how childhood body mass index (BMI) influences later risk of obesity. We calculated BMIs for children residing in Olmsted County, Minnesota, between January 1, 2005 and December 31, 2012 using medical records data. We defined homogenous BMI trajectory clusters using a nonparametric hill-climbing algorithm. Overall, 16,538 (47%) children had >3 weight assessments at least 1 year apart and were included in the analyses. Within the 8-year follow-up period, children who were younger than 2 years and overweight had a 3- fold increase of obesity (adjusted hazard ratio [HR] = 3.24; 95% confidence interval [CI] = 2.69-3.89) and those aged 5 years and overweight had a 10-fold increased risk of obesity (adjusted HR = 9.97, 95% CI = 8.55-11.62). Three distinct BMI trajectories could be distinguished prior to 5 years of age. The risk of developing obesity in those who are overweight increased dramatically with increasing age. Interventions to prevent obesity need to occur prior to school age to prevent children from entering unhealthy BMI trajectories.

Associations among the Degree of Nonalcoholic Fatty Liver Disease, Metabolic Syndrome, Degree of Obesity in Children, and Parental Obesity

PURPOSE

To analyze the associations among the degrees of nonalcoholic fatty liver disease (NAFLD) by ultrasonography and metabolic syndrome, degrees of obesity in children, and degrees of parental obesity.

METHODS

A total of 198 children with obesity who visited a pediatric obesity clinic were prospectively enrolled in this study. The severity of NAFLD based on ultrasonography was classified into no, mild, moderate, or severe NAFLD group. The degree of obesity based on the percentage over standard weight for height per sex was classified into mild, moderate, or severe.

RESULTS

Of 132 patients evaluated for the degree of NAFLD and metabolic syndrome, the p-value of correlation between the two factors was 0.009. Therefore, metabolic syndrome might significantly affect the degree of NAFLD. Of 158 patients evaluated for the degree of NAFLD and the degree of obesity, the p-value of correlation between the two factors was 0.122. Of 154 patients evaluated for the degree of obesity and father's obesity, the p-value was 0.076. Of 159 patients evaluated for the degree of obesity and mother's obesity, the p-value was 0.000, indicating that mother's obesity could significantly affect the degree of obesity in children. Of 142 patients evaluated for the degree of obesity and metabolic syndrome, the p-value was 0.288.

CONCLUSION

Metabolic syndrome might significantly affect the degree of nonalcoholic fatty liver in children. In addition, mother's obesity might be a significant factor that affects the degree of obesity in children.

Comparison of Controlled Attenuation Parameter and Liver Biopsy to Assess Hepatic Steatosis in Pediatric Patients

OBJECTIVE

To assess whether the degree of steatosis as determined by controlled attenuation parameter (CAP) measurements correlates with that observed on liver biopsies in a single-center pediatric and young adult cohort.

STUDY DESIGN

This cross-sectional study included patients undergoing liver biopsy as part of standard clinical care between January 25, 2012, and April 1, 2015, at Boston Children's Hospital. Eligible patients, with a variety of liver diseases, had CAP measurements within 1 year of biopsy. CAP values were compared across histologic steatosis grades using ANOVA.

RESULTS

Sixty-nine patients (mean age, 16.0 ± 2.9 years; 62% male) were studied. CAP measurements were obtained at a median of 1.3 months (IQR, 0.5-3.2) after biopsy. Of the 69 subjects, 23 had steatosis on biopsy. Mean CAP value (dB/m) for subjects with no steatosis was 198 ± 37 vs 290 ± 47 for subjects with steatosis (P < .0001). There were statistically significant differences between CAP values in individuals with no steatosis vs mild/moderate steatosis (P < .0001), no steatosis vs marked steatosis (P < .0001), and mild/moderate vs marked steatosis (P = .004).

CONCLUSION

This study demonstrated a difference in CAP between no steatosis and steatosis, and between grades of steatosis. CAP may be a useful noninvasive tool to detect hepatic steatosis in children.

Mainstream cigarette smoke accelerates the progression of nonalcoholic steatohepatitis by modulating Kupffer cell-mediated hepatocellular apoptosis in adolescent mice

Cigarette smoking in adolescents is considered to be a major cause of preventable morbidity and mortality. The purpose of this study is to investigate the role of mainstream cigarette smoke (MSCS) on the progression of nonalcoholic steatohepatitis in adolescents. Three-week-old C57BL/6 mice were fed either a methionine and choline-deficient plus high fat (MCDHF) diet for 6 weeks. Each group was exposed to MSCS (300, 600 ug/L) or fresh air for 2h per day during the first 3 weeks of MCDHF diet feeding. MSCS increased MCDHF diet-induced NASH by increasing serum ALT/AST levels, steatosis, inflammation, and fibrosis. Furthermore, MSCS was associated with the degree of oxidative stress and hepatocellular apoptosis in NASH mice, but not prominent in controls. In vitro, cigarette smoke extract (CSE) activated Kupffer cells (KCs) to release inflammatory cytokines and oxidative stress, which induced hepatocellular apoptosis. In conclusion, MSCS exposure accelerates the progression and severity of NASH by modulating KC-mediated hepatocellular apoptosis. Our results support the regulation of CS in adolescents with steatohepatitis.

Relationship between Neck Circumference and Non-Alcoholic Fatty Liver Disease in Childhood Obesity

OBJECTIVE

The aim of this study was to establish the association between anthropometric parameters and non-alcoholic fatty liver disease (NAFLD) and to determine the most reliable measurement as a parameter in predicting NAFLD.

METHODS

Two-hundred fifty-three obese children of ages 10 to 18 years were enrolled in this study. Anthropometric data and metabolic parameters such as fasting blood glucose, insulin and lipid levels, were measured. Liver function tests were assessed. NAFLD was determined by ultrasound.

RESULTS

Most metabolic parameters and anthropometric indices were significantly higher in children with NAFLD. A univariate logistic regression analysis was performed, taking NAFLD status as the dependent variable and anthropometric parameters as the independent variables. NAFLD was affected significantly by the anthropometric values. The multiple logistic regression analysis showed that neck circumference (NC) was the only parameter which determined the risk in both genders. Each 1 cm increase in the NC increased the risk of NAFLD 1.544-fold (p<0.001, 95% confidence interval (CI): 1.357-2.214) in the boys and 1.733-fold (p=0.001, 95% CI: 1.185-2.012) in the girls. Receiver operating characteristic analysis was performed to compare the reliability of anthropometric measurements. NC was observed to be a better indicator.

CONCLUSION

Measurement of the NC was shown to be associated with NAFLD in children. We suggest the use of NC as a novel, simple, practical, and reliable anthropometric index in predicting children at risk for NAFLD.

Quantitative relationship between liver fat content and metabolic syndrome in obese children and adolescents

OBJECTIVE

Previous studies have shown a significant association between quantified liver fat content (LFC) and metabolic syndrome (MetS) in adults, but the nature of this association in obese paediatric populations is unclear. The aim of this study was to investigate the quantitative relationship of LFC to MetS and its individual components in obese children and adolescents.

DESIGN

A population-based cross-sectional study.

PATIENTS AND MEASUREMENTS

One hundred and eighty-nine Chinese obese paediatric subjects aged 5-16 years were enrolled. Measurements included MetS components, as defined by the Chinese-specific version of the International Diabetes Foundation MetS criteria (MetS-CHN2012), and LFC using proton magnetic resonance spectroscopy.

RESULTS

LFC was significantly higher in subjects with MetS [median 9.7% (interquartile range 4.5-19.9%)] than without MetS [5.7% (2.0-12.8%)] (P < 0.01). LFC was also positively associated with the total number of MetS components (P for trend <0.01). In analyses adjusted for traditional risk factors, increasing levels of LFC were associated with a greater risk of MetS, hypertriglyceridaemia and low high-density lipoprotein cholesterol (P < 0.05 for all associations), but were not associated with risk of hyperglycaemia or hypertension.

CONCLUSIONS

In obese Chinese paediatric patients, quantitative measures of LFC are positively associated with the risk of MetS, hypertriglyceridaemia and low high-density lipoprotein cholesterol, independent of traditional risk factors. These findings suggest that quantitatively measured LFC may be a clinically useful marker for identifying obese paediatric who are at increased risk of developing MetS and its components.

Dysfunctional mitochondrial bioenergetics and the pathogenesis of hepatic disorders

The liver is involved in a variety of critical biological functions including the homeostasis of glucose, fatty acids, amino acids, and the synthesis of proteins that are secreted in the blood. It is also at the forefront in the detoxification of noxious metabolites that would otherwise upset the functioning of the body. As such, this vital component of the mammalian system is exposed to a notable quantity of toxicants on a regular basis. It therefore comes as no surprise that there are over a hundred disparate hepatic disorders, encompassing such afflictions as fatty liver disease, hepatitis, and liver cancer. Most if not all of liver functions are dependent on energy, an ingredient that is primarily generated by the mitochondrion, the power house of all cells. This organelle is indispensable in providing adenosine triphosphate (ATP), a key effector of most biological processes. Dysfunctional mitochondria lead to a shortage in ATP, the leakage of deleterious reactive oxygen species (ROS), and the excessive storage of fats. Here we examine how incapacitated mitochondrial bioenergetics triggers the pathogenesis of various hepatic diseases. Exposure of liver cells to detrimental environmental hazards such as oxidative stress, metal toxicity, and various xenobiotics results in the inactivation of crucial mitochondrial enzymes and decreased ATP levels. The contribution of the latter to hepatic disorders and potential therapeutic cues to remedy these conditions are elaborated.

Arginase 2 deficiency results in spontaneous steatohepatitis: a novel link between innate immune activation and hepatic de novo lipogenesis

BACKGROUND & AIMS

Innate immune activation has been postulated as a central mechanism for disease progression from hepatic steatosis to steatohepatitis in obesity-related fatty liver disease. Arginase 2 competes with inducible nitric oxide synthase (iNOS) for its substrate and the balance between these two enzymes plays a crucial role in regulating immune responses and macrophage activation. Our aim was to test the hypothesis that arginase 2 deficiency in mice favours progression from isolated hepatic steatosis, induced by high fat feeding, to steatohepatitis.

METHODS

Arginase 2-knockout (Arg2(-/-)) mice were studied for changes in liver histology and metabolic phenotype at baseline and after a short term course (7 week) feeding with a high fat (HFAT) diet. In additional experiments, Arg2(-/-) mice received tail vein injections of liposome-encapsulated clodronate (CLOD) over a three-week period to selectively deplete liver macrophages.

RESULTS

Unexpectedly, Arg2(-/-) mice showed profound changes in their livers at baseline, characterized by significant steatosis as demonstrated with histological and biochemical analysis. These changes were independent of systemic metabolic parameters and associated with marked mRNA level increases of genes involved in hepatic de novo lipogenesis. Liver injury and inflammation were present with elevated serum ALT, marked infiltration of F4/80 positive cells, and increased mRNA levels of inflammatory genes. HFAT feeding exacerbated these changes. Macrophage depletion after CLOD injection significantly attenuated lipid deposition and normalized lipogenic mRNA profile of livers from Arg2(-/-) mice.

CONCLUSIONS

This study identifies arginase 2 as a novel link between innate immune responses, hepatic lipid deposition, and liver injury.

A non-invasive prediction model for non-alcoholic steatohepatitis in paediatric patients with non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease encompasses a spectrum of diseases that range from simple steatosis to the aggressive form of non-alcoholic steatohepatitis. Non-alcoholic steatohepatitis is currently diagnosed through liver biopsy.

AIM

To develop a non-invasive predictive model of non-alcoholic steatohepatitis in children with non-alcoholic fatty liver disease.

METHODS

Anthropometric, laboratory, and histologic data were obtained in a cohort of children with biopsy-proven non-alcoholic fatty liver disease. Multivariable logistic regression analysis was employed to create a nomogram predicting the risk of non-alcoholic steatohepatitis. Internal validation was performed by bootstrapping.

RESULTS

Three hundred and two children were included in this analysis with a mean age of 12.3 ± 3.1 years, a mean body mass index percentile of 94.3 ± 6.9, and non-alcoholic steatohepatitis was present in 67%. Following stepwise variable selection, total cholesterol, waist circumference percentile, and total bilirubin were included as variables in the model, with good discrimination with an area under the receiver operating characteristic curve of 0.737.

CONCLUSIONS

A nomogram was constructed with reasonable accuracy that can predict the risk of non-alcoholic steatohepatitis in children with non-alcoholic fatty liver disease. If validated externally, this tool could be utilized as a non-invasive method to diagnose non-alcoholic steatohepatitis in children with non-alcoholic fatty liver disease.

Oxidative stress, cardiolipin and mitochondrial dysfunction in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is today considered the most common form of chronic liver disease, affecting a high proportion of the population worldwide. NAFLD encompasses a large spectrum of liver damage, ranging from simple steatosis to steatohepatitis, advanced fibrosis and cirrhosis. Obesity, hyperglycemia, type 2 diabetes and hypertriglyceridemia are the most important risk factors. The pathogenesis of NAFLD and its progression to fibrosis and chronic liver disease is still unknown. Accumulating evidence indicates that mitochondrial dysfunction plays a key role in the physiopathology of NAFLD, although the mechanisms underlying this dysfunction are still unclear. Oxidative stress is considered an important factor in producing lethal hepatocyte injury associated with NAFLD. Mitochondrial respiratory chain is the main subcellular source of reactive oxygen species (ROS), which may damage mitochondrial proteins, lipids and mitochondrial DNA. Cardiolipin, a phospholipid located at the level of the inner mitochondrial membrane, plays an important role in several reactions and processes involved in mitochondrial bioenergetics as well as in mitochondrial dependent steps of apoptosis. This phospholipid is particularly susceptible to ROS attack. Cardiolipin peroxidation has been associated with mitochondrial dysfunction in multiple tissues in several physiopathological conditions, including NAFLD. In this review, we focus on the potential roles played by oxidative stress and cardiolipin alterations in mitochondrial dysfunction associated with NAFLD.

ASPP2 attenuates triglycerides to protect against hepatocyte injury by reducing autophagy in a cell and mouse model of non-alcoholic fatty liver disease

ASPP2 is a pro-apoptotic member of the p53 binding protein family. ASPP2 has been shown to inhibit autophagy, which maintains energy balance in nutritional deprivation. We attempted to identify the role of ASPP2 in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). In a NAFLD cell model, control treated and untreated HepG2 cells were pre-incubated with GFP-adenovirus (GFP-ad) for 12 hrs and then treated with oleic acid (OA) for 24 hrs. In the experimental groups, the HepG2 cells were pre-treated with ASPP2-adenovirus (ASPP2-ad) or ASPP2-siRNA for 12 hrs and then treated with OA for 24 hrs. BALB/c mice fed a methionine- and choline-deficient (MCD) diet were used to generate a mouse model of NAFLD. The mice with fatty livers in the control group were pre-treated with injections of GFP-ad for 10 days. In the experimental group, the mice that had been pre-treated with ASPP2-ad were fed an MCD diet for 10 days. ASPP2-ad or GFP-ad was administered once every 5 days. Liver tissue from fatty liver patients and healthy controls were used to analyse the role of ASPP2. Autophagy, apoptosis markers and lipid metabolism mediators, were assessed with confocal fluorescence microscopy, immunohistochemistry, western blot and biochemical assays. ASPP2 overexpression decreased the triglyceride content and inhibited autophagy and apoptosis in the HepG2 cells. ASPP2-ad administration suppressed the MCD diet-induced autophagy, steatosis and apoptosis and decreased the previously elevated alanine aminotransferase levels. In conclusion, ASPP2 may participate in the lipid metabolism of non-alcoholic steatohepatitis and attenuate liver failure.

Weight trajectories through infancy and childhood and risk of non-alcoholic fatty liver disease in adolescence: the ALSPAC study

BACKGROUND & AIMS

Adiposity is a key risk factor for NAFLD. Few studies have examined prospective associations of infant and childhood adiposity with subsequent NAFLD risk. We examined associations of weight-for-height trajectories from birth to age 10 with liver outcomes in adolescence, and assessed the extent to which associations are mediated through fat mass at the time of outcome assessment.

METHODS

Individual trajectories of weight and height were estimated for participants in the Avon Longitudinal Study of Parents and Children using random-effects linear-spline models. Associations of birthweight (adjusted for birth length) and weight change (adjusted for length/height change) from 0-3 months, 3 months-1 y, 1-3 y, 3-7 y, and 7-10 y with ultrasound scan (USS) determined liver fat and stiffness, and serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT) at mean age 17.8 y were assessed with linear and logistic regressions. Mediation by concurrent fat mass was assessed with adjustment for fat mass at mean age 17.8 y.

RESULTS

Birth weight was positively associated with liver stiffness and negatively with ALT and AST. Weight change from birth to 1 y was not associated with outcomes. Weight change from 1-3 y, 3-7 y, and 7-10 y was consistently positively associated with USS and blood-based liver outcomes. Adjusting for fat mass at mean age 17.8 y attenuated associations toward the null, suggesting associations are largely mediated by concurrent body fatness.

CONCLUSIONS

Greater rates of weight-for-height change between 1 y and 10 y are consistently associated with adverse liver outcomes in adolescence. These associations are largely mediated through concurrent fatness.

Non-high-density lipoprotein cholesterol (non-HDL-C) levels in children with nonalcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is associated with increased cardiovascular disease (CVD) risk in children. Non-high density lipoprotein-cholesterol (non-HDL-C) has been shown to be a good predictor of cardiovascular events. Recent data in adults found non-alcoholic steatohepatitis (NASH) to be associated with significantly higher levels of non–HDL-C than simple steatosis, suggestive it might be used as a non-invasive tool to diagnose NASH. The goal of our study was to assess non-HDL-C levels in children with NAFLD. Our cohort consisted of pediatric patients with biopsy-proven NAFLD. Anthropometric, laboratory, and histologic data were obtained on all patients. Univariable analysis was performed to assess differences in clinical characteristics between groups. Spearman rank correlation coefficients were calculated to assess the correlation between non-HDL-C levels and clinical variables. ANCOVA was used to adjust for possible confounders. 302 subjects with NAFLD were included in our study; 203 with NASH and 99 without NASH. Subjects with NASH had significantly higher non-HDL-C levels than those without (p = 0.004). Histologic features of NASH, including ballooning, inflammation, and fibrosis were found to be weakly correlated with non-HDL-C levels, (p < 0.05 for all). After adjusting for the presence of metabolic syndrome (MetS), ALT, and GGT, the association between non-HDL-C and NASH was not significant (p = 0.66). In Conclusion, non-HDL-C levels are higher in children with NASH than those with simple steatosis, suggesting increased CVD risk. This may be a reflection of the higher prevalence of MetS. Non-HDL-C had a positive association with histologic features of NASH.

Caspase 3 inactivation protects against hepatic cell death and ameliorates fibrogenesis in a diet-induced NASH model

BACKGROUND/AIMS

Hepatocyte cell death is a key feature of nonalcoholic steatohepatitis (NASH). As the contribution of specific caspases remains unclear, our aim was to ascertain the effect of caspase 3 suppression on liver injury and fibrogenesis.

METHODS

C57BL/6 wild-type (WT) and caspase 3 knock out (Casp3 (-/-)) mice were placed on a methionine- and choline-deficient (MCD) diet for 6 weeks to induce steatohepatitis and liver fibrosis. Thereafter, liver injury, liver fibrosis and hepatocellular apoptosis were quantified in liver sections. Additionally, expression of proteins associated with liver inflammation and fibrogenesis was analyzed.

RESULTS

WT mice fed MCD diet showed marked activation of caspase 3 in hepatocytes, in conjunction with steatohepatitis and increased hepatic triglyceride levels, hepatocyte ballooning, inflammation and fibrosis. Casp3 (-/-) mice fed the MCD diet showed similar serum aminotransferase levels and NAFLD activity scores (NAS) compared with WT MCD-fed mice. However, Casp3 (-/-) mice on the MCD diet showed a marked reduction in expression of transcripts for profibrogenic genes, which translated into reduced hepatic collagen deposition. These changes were associated with decreased levels of apoptosis, and a significant reduction in the expression of cytokines involved in inflammatory signaling. Casp3 (-/-) mice on the MCD showed a reduction in expression of chemokine receptor 2 (CCR2) leading to ameliorated infiltration of inflammatory lymphocyte antigen 6 complex, locus C1 (Ly6c) positive monocytes.

CONCLUSION

These findings support a prominent role for hepatocyte caspase 3 activation in NASH-related apoptosis, fibrogenesis and fibrosis which in part is mediated via CCR2-dependent infiltration of Ly6c positive monocytes.

Noninvasive Diagnosis of NASH and Liver Fibrosis Within the Spectrum of NAFLD

Nonalcoholic fatty liver disease (NAFLD) is the most common type of chronic liver disease in the United States, affecting an estimated 70 million Americans. The histologic spectrum of NAFLD ranges from simple steatosis to nonalcoholic steatohepatitis (NASH), fibrosis, and eventually cirrhosis. Patients with NASH and significant fibrosis seen on liver biopsy have an increased risk for liver-related morbidity and mortality compared to patients with simple steatosis. Due to the high prevalence of NAFLD, there has been an urgent need to develop reliable noninvasive markers and tests that can accurately predict the presence of advanced disease without the need for liver biopsy. These tests can be divided into 2 groups: those that predict the presence of NASH (such as markers of hepatocyte apoptosis, oxidative stress, and inflammation, as well as predictive models based on clinical variables) and those that predict the presence of fibrosis (such as simple and complex predictive models). This paper provides an overview of various noninvasive methods for detecting NAFLD and suggests a diagnostic algorithm that can be used in clinical practice.

Obesity, nutrition, and liver disease in children

In this article, several aspects of childhood obesity are discussed, including epidemiology, associated metabolic complications, management strategies, and therapy with particular attention to the impact of obesity on the liver, resulting in nonalcoholic or metabolic fatty liver disease. The deleterious effects of obesity on the liver and health overall can be significantly impacted by a culture that fosters sustained nutritional improvement and regular physical activity. The current evidence is summarized supporting pharmacologic, behavioral, and dietary interventions for the management of obesity and fatty liver disease in children.

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.

Sonographic quantification of a hepato-renal index for the assessment of hepatic steatosis in comparison with 3T proton magnetic resonance spectroscopy

CONTEXT

Nonalcoholic fatty liver disease is the most frequent hepatic disorder in the developed world. Currently, liver biopsy and proton magnetic resonance spectroscopy (H-MRS) are considered the gold standard methods for the quantification of liver fat deposits.

OBJECTIVE

To determine whether a Sonographic Hepato-Renal Index (SHRI) calculated using a standard workstation, without a specifically designed software, is an adequate alternative to H-MRS for the quantification of fat liver content and diagnosis of steatosis in the general population.

METHODS

A total of 121 volunteers (mean age=46 years, range=21-77 years) were recruited at three medical centers in Granada (Southern Spain) from among individuals attending routine general checkups. All participants were examined by ultrasound and by H-MRS 3T, which served as a reference for the diagnosis of steatosis. The SHRI was calculated as the ratio between the echogenicity of the liver and that of the right renal parenchyma. The validity of the methodology was assessed by receiver operating characteristic curves and correlation tests.

RESULTS

The quantitative SHRI showed a strong correlation (Spearman's coefficient=0.89, P<0.001) with the H-MRS 3T. The optimal SHRI cutoff points of 1.21, 1.28, and 2.15 yielded 100% sensitivity for the diagnoses of steatosis greater than 5, 25, and 50%, respectively, with a specificity greater than 70%.

CONCLUSION

This study shows that the SHRI is a valid, simple, reliable, and cost-effective screening tool for the identification, assessment, and quantification of hepatic steatosis in the general population.

MRI-diagnosed nonalcoholic fatty liver disease is correlated to insulin resistance in adolescents

RATIONALE AND OBJECTIVES

To evaluate the presence of nonalcoholic fatty liver disease (NAFLD) in eutrophic and obese adolescents with magnetic resonance imaging (MRI) and its relationship to insulin resistance and other potential biomarkers.

MATERIALS AND METHODS

A total of 50 adolescents (aged 11-17 years), including 24 obese and 26 eutrophic adolescents, were evaluated using MRI exams for NAFLD diagnosis. Blood analysis was performed to measure glucose, insulin, total cholesterol, high-density lipoprotein cholesterol, triglycerides, fibrinogen, aminotransferases, alkaline phosphatase, gamma-gt, and C-reactive protein. The Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) index was also calculated. Laboratory test results and anthropometric assessment were statistically analyzed to determine potential correlation with NAFLD prevalence.

RESULTS

The prevalence of NAFLD among the obese was significantly higher (83.3%; CI 95: 64.5-94.5%) than that of the eutrophic group (19.2%; CI 95: 7.4-37.6%). In multivariate analysis, only HOMA-IR was an independent risk factor for diagnosis NAFLD using MRI. Compared to eutrophic adolescents, the obese adolescents had significantly higher levels for all parameters measured except for total and high-density lipoprotein cholesterol, which were significantly lower.

CONCLUSION

The prevalence of NAFLD was 19.2% among eutrophic patients and 83.3% among obese patients. Only HOMA-IR was determined to be an independent risk factor for NAFLD.

Lipid-induced toxicity stimulates hepatocytes to release angiogenic microparticles that require Vanin-1 for uptake by endothelial cells

Angiogenesis is a key pathological feature of experimental and human steatohepatitis, a common chronic liver disease that is associated with obesity. We demonstrated that hepatocytes generated a type of membrane-bound vesicle, microparticles, in response to conditions that mimicked the lipid accumulation that occurs in the liver in some forms of steatohepatitis and that these microparticles promoted angiogenesis. When applied to an endothelial cell line, medium conditioned by murine hepatocytes or a human hepatocyte cell line exposed to saturated free fatty acids induced migration and tube formation, two processes required for angiogenesis. Medium from hepatocytes in which caspase 3 was inhibited or medium in which the microparticles were removed by ultracentrifugation lacked proangiogenic activity. Isolated hepatocyte-derived microparticles induced migration and tube formation of an endothelial cell line in vitro and angiogenesis in mice, processes that depended on internalization of microparticles. Microparticle internalization required the interaction of the ectoenzyme Vanin-1 (VNN1), an abundant surface protein on the microparticles, with lipid raft domains of endothelial cells. Large quantities of hepatocyte-derived microparticles were detected in the blood of mice with diet-induced steatohepatitis, and microparticle quantity correlated with disease severity. Genetic ablation of caspase 3 or RNA interference directed against VNN1 protected mice from steatohepatitis-induced pathological angiogenesis in the liver and resulted in a loss of the proangiogenic effects of microparticles. Our data identify hepatocyte-derived microparticles as critical signals that contribute to angiogenesis and liver damage in steatohepatitis and suggest a therapeutic target for this condition.

Role of physical activity in the treatment of nonalcoholic fatty liver disease in children and adolescents

Currently, nonalcoholic fatty liver disease (NAFLD) is the most frequent liver abnormality observed in obese children and adolescents. A strong body of evidence suggests that increased liver fat is significantly associated with visceral adiposity, metabolic syndrome, and insulin resistance in obese children and adolescents. Diet and exercise are generally recommended to treat obese youth with NAFLD as they do not carry side effects and confer multiple cardiometabolic benefits. Studies in adult populations report a beneficial effect of regular physical activity on reducing liver fat. In children and adolescents, available data show that weight loss induced by increasing physical activity and calorie restriction is beneficial to reduce liver fat and associated health risk factors such as insulin resistance and dyslipidemia. Currently, evidence regarding the independent effects of regular exercise alone (e.g., without calorie restriction) on NAFLD are unclear. Additionally, there is no data regarding the optimal exercise regimen (e.g., type, dose, intensity) that should be prescribed for reducing NAFLD in children and adolescents. The purpose of this review is to examine the role of physical activity on NAFLD in children and adolescents.

Novel therapeutic targets for nonalcoholic fatty liver disease

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is a serious public health problem. It is now estimated to affect 30% of adults and about 10% of children in the U.S. Hispanics are disproportionably affected with not only higher rates of NAFLD but also more severe disease. Treatment options are currently limited.

AREAS COVERED

In this review, we will focus on a series of novel findings related to the pathobiology of liver damage in nonalcoholic steatohepatitis (NASH) that are attractive targets for development of novel therapeutic strategies for human NASH. In particular, we will discuss four different areas due to their novelty and growing importance including microparticles, the inflammasomes, gut-liver axis and dietary lipids.

EXPERT OPINION

There is an urgent need to develop novel safe and effective therapies for the growing NAFLD epidemic. The data discussed in this article provide strong rational to think out of the box when considering novel therapeutic targets for patients with NAFLD.

Metabolomic profiling reveals a role for caspase-2 in lipoapoptosis

The accumulation of long-chain fatty acids (LCFAs) in non-adipose tissues results in lipid-induced cytotoxicity (or lipoapoptosis). Lipoapoptosis has been proposed to play an important role in the pathogenesis of several metabolic diseases, including non-alcoholic fatty liver disease, diabetes mellitus, and cardiovascular disease. In this report, we demonstrate a novel role for caspase-2 as an initiator of lipoapoptosis. Using a metabolomics approach, we discovered that the activation of caspase-2, the initiator of apoptosis in Xenopus egg extracts, is associated with an accumulation of LCFA metabolites. Metabolic treatments that blocked the buildup of LCFAs potently inhibited caspase-2 activation, whereas adding back an LCFA in this scenario restored caspase activation. Extending these findings to mammalian cells, we show that caspase-2 was engaged and activated in response to treatment with the saturated LCFA palmitate. Down-regulation of caspase-2 significantly impaired cell death induced by saturated LCFAs, suggesting that caspase-2 plays a pivotal role in lipid-induced cytotoxicity. Together, these findings reveal a previously unknown role for caspase-2 as an initiator caspase in lipoapoptosis and suggest that caspase-2 may be an attractive therapeutic target for inhibiting pathological lipid-induced apoptosis.

Pediatric Obesity and the Liver

The obesity epidemic affects both the adult and pediatric populations. Obese children are at risk for comorbidities such as cardiovascular disease and nonalcoholic fatty liver disease (NAFLD). NAFLD is the most common cause of pediatric liver disease and prevalence rates are increasing in parallel to obesity rates. Pediatric NAFLD is a difficult diagnostic entity complicated by lack of accurate noninvasive screening tools. Currently, microscopic liver examination biopsy is the gold standard for diagnosis. Histologically, NAFLD can range from simple steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis. Pediatric NASH is histologically distinct from typical adult NASH. Type 2 NASH, originally described as the most common pattern of pediatric NASH, is characterized by macrovesicular steatosis, portal tract inflammation, and variable fibrosis without ballooning degeneration or perisinusoidal fibrosis. Type 1 NASH, or adult NASH, is characterized by macrovesicular steatosis, ballooning degeneration, lobular inflammation, and variable fibrosis. Recent studies have shown that overlap patterns between NASH type 1 and 2 are more frequently encountered in the pediatric population. We address the association between pediatric obesity and nonalcoholic fatty liver disease (NAFLD) with discussion of disease demographics, histopathology, and the role of autopsy.

Caspase-1 as a central regulator of high fat diet-induced non-alcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is associated with caspase activation. However, a role for pro-inflammatory caspases or inflammasomes has not been explored in diet-induced liver injury. Our aims were to examine the role of caspase-1 in high fat-induced NASH. C57BL/6 wild-type and caspase 1-knockout (Casp1(-/-)) mice were placed on a 12-week high fat diet. Wild-type mice on the high fat diet increased hepatic expression of pro-caspase-1 and IL-1β. Both wild-type and Casp1(-/-) mice on the high fat diet gained more weight than mice on a control diet. Hepatic steatosis and TG levels were increased in wild-type mice on high fat diet, but were attenuated in the absence of caspase-1. Plasma cholesterol and free fatty acids were elevated in wild-type, but not Casp1(-/-) mice, on high fat diet. ALT levels were elevated in both wild-type and Casp1(-/-) mice on high fat diet compared to control. Hepatic mRNA expression for genes associated with lipogenesis was lower in Casp1(-/-) mice on high fat diet compared to wild-type mice on high fat diet, while genes associated with fatty acid oxidation were not affected by diet or genotype. Hepatic Tnfα and Mcp-1 mRNA expression was increased in wild-type mice on high fat diet, but not in Casp1(-/-) mice on high fat diet. αSMA positive cells, Sirius red staining, and Col1α1 mRNA were increased in wild-type mice on high fat diet compared to control. Deficiency of caspase-1 prevented those increases. In summary, the absence of caspase-1 ameliorates the injurious effects of high fat diet-induced obesity on the liver. Specifically, mice deficient in caspase-1 are protected from high fat-induced hepatic steatosis, inflammation and early fibrogenesis. These data point to the inflammasome as an important therapeutic target for NASH.

Noninvasive biomarkers for the diagnosis of steatohepatitis and advanced fibrosis in NAFLD

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of abnormal liver enzymes in both adults and children. NAFLD has a histologic spectrum ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), advanced fibrosis, and cirrhosis. It is imperative to distinguish simple steatosis from NASH since the latter has a progressive disease course and can lead to end-stage liver disease. Liver biopsy has been considered as the gold standard for the diagnosis of NASH. However, liver biopsy is invasive, costly, and can rarely cause significant morbidity (risk of morbidity, 0.06-0.35%; risk of mortality, 0.1-0.01%). Imaging studies such as ultrasonography, computed tomography, and magnetic resonance imaging have limited sensitivity in detecting steatosis and cannot distinguish steatosis from NASH. Alanine aminotransferase (ALT) has been used as a surrogate marker for liver injuries. However, ALT is not an ideal marker for either diagnosis of NAFLD or distinguishing steatosis from NASH. Better noninvasive biomarkers or panels of biomarkers that are cheaper, reliable, and reproducible are urgently needed for patients with NASH to assist in establishing diagnosis, providing risk information, and monitoring disease progression and treatment response. In this article, we plan to concisely review the current advances in the use of biomarkers for the diagnosis of NASH.

Alterations in adipocytokines and cGMP homeostasis in morbid obesity patients reverse after bariatric surgery

OBJECTIVE

Obesity-associated nonalcoholic fatty liver disease (NAFLD), covering from simple steatosis to nonalcoholic steatohepatitis (NASH), is a common cause of chronic liver disease. Aberrant production of adipocytokines seems to play a main role in most obesity-associated disorders. Changes in adipocytokines in obesity could be mediated by alterations in cyclic GMP (cGMP) homeostasis. The aims of this work were: (1) to study the role of altered cGMP homeostasis in altered adipocytokines in morbid obesity, (2) to assess whether these alterations are different in simple steatosis or NASH, and (3) to assess whether these changes reverse in obese patients after bariatric surgery.

DESIGN AND METHODS

In 47 patients with morbid obesity and 45 control subjects, the levels in blood of adipocytokines, cGMP, nitric oxide (NO) metabolites, and atrial natriuretic peptide (ANP) were studied. Whether weight loss after a bariatric surgery reverses the changes in these parameters was evaluated.

RESULTS

NO metabolites and leptin increase (and adiponectin decreases) similarly in patients with steatosis or NASH, suggesting that these changes are due to morbid obesity and not to liver disease. Inflammation and cGMP homeostasis are affected both by morbid obesity and by liver disease. The increases in interleukin 6 (IL-6), interleukin 18 (IL-18), plasma cGMP, ANP, and the decrease in cGMP in lymphocytes are stronger in patients with NASH than with steatosis. All these changes reverse completely after bariatric surgery and weight loss, except IL-18.

CONCLUSION

Altered cGMP homeostasis seems to contribute more than inflammation to changes in leptin and adiponectin in morbid obesity.

Combined paediatric NAFLD fibrosis index and transient elastography to predict clinically significant fibrosis in children with fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum of disease from simple steatosis to steatohepatitis, to fibrosis and cirrhosis. The paediatric NAFLD fibrosis index (PNFI) and transient elastography (TE) are potential noninvasive markers for fibrosis. To prospectively evaluate the performance of PNFI and TE in assessing clinically significant fibrosis in children with biopsy-proven NAFLD.

METHODS

Our cohort consisted of 67 consecutive children with biopsy-proven NAFLD. The stage of fibrosis was scored according to the Nonalcoholic Steatohepatitis Clinical Research Network. Fibrosis ≥ 2 was considered clinically significant. PNFI was calculated using age, waist circumference and triglycerides. TE was performed using the Fibroscan apparatus.

RESULTS

Ten patients had fibrosis stage 2-3 and 57 patients had stage 0-1. Both PNFI and TE values were significantly higher in patients with significant fibrosis (P < 0.05). The area under the receiver operating characteristic (ROC) curve for predicting significant fibrosis of PNFI and TE were 0.747 and 1.00 respectively (P = 0.005). The combined use of PNFI and TE could predict the presence or absence of clinically significant fibrosis in 98% of children with NAFLD.

CONCLUSIONS

In children with NAFLD, the combination of PNFI and TE can be used to accurately assess the presence of clinically significant liver fibrosis. This will help to identify patients who should undergo liver biopsy because the confirmation of advanced fibrosis would lead to closer follow-up and screening for cirrhosis-related complications.

Caspase-1-mediated regulation of fibrogenesis in diet-induced steatohepatitis

Non-alcoholic steatohepatitis (NASH) is typically associated with pro-apoptotic caspase activation. A potential role for pro-inflammatory caspases remains incompletely understood. Our aims were to examine a potential role of caspase-1 in the development of liver damage and fibrosis in NASH. C57BL/6 wild type (WT) developed marked steatohepatitis, activation, fibrosis and increased hepatic caspase-1 and interleukin-1β expression when placed on the methionine- and choline-deficient (MCD) diet. Marked caspase-1 activation was detected in the liver of MCD-fed mice. Hepatocyte and non-parenchymal fractionation of the livers further demonstrated that caspase-1 activation after MCD feeding was mainly localized to non-parenchymal cells. Caspase-1-knockout (Casp1(-/-)) mice on the MCD diet showed marked reduction in mRNA expression of genes involved in inflammation and fibrogenesis (tumor necrosis factor-α was 7.6-fold greater in WT vs Casp1(-/-) MCD-fed mice; F4/80 was 1.5-fold greater in WT vs Casp1(-/-) MCD-fed mice; α-smooth muscle actin was 3.2-fold greater in WT vs Casp1(-/-) MCD-fed mice; collagen 1-α was 7.6-fold greater in WT vs Casp1(-/-) MCD-fed mice; transforming growth factor-β was 2.4-fold greater in WT vs Casp1(-/-) MCD-fed mice; cysteine- and glycine-rich protein 2 was 3.2-fold greater in WT vs Casp1(-/-) MCD-fed mice). Furthermore, Sirius red staining for hepatic collagen deposition was significantly reduced in Casp1(-/-) MCD-fed mice compared with WT MCD-fed animals. However, serum alanine aminotransferase levels, caspase-3 activity and terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells were similar in Casp1(-/-) and WT mice on the MCD diet. Selective Kupffer cell depletion by clodronate injection markedly suppressed MCD-induced caspase-1 activation and protected mice from fibrogenesis and fibrosis associated with this diet. The conclusion of this study is that it uncovers a novel role for caspase-1 in inflammation and fibrosis during NASH development.

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.

Physical activity and nutrition attitudes in obese Hispanic children with non-alcoholic steatohepatitis

AIM: To assess nutrition, physical activity and healthful knowledge in obese children with biopsy-proven non-alcoholic steatohepatitis (NASH or NA) compared to children without liver disease.

METHODS: Children with biopsy-proven NASH comprised the NASH group. Age, sex and ethnicity matched control groups consisted of obese (OB) and lean (CO) children with no liver disease. Subjects were administered the School Physical Activity and Nutrition Survey and one blood draw was obtained.

RESULTS: Fifty-seven patients were enrolled with a mean age of 12.1 ± 2.1 years, and all were Hispanic. Even though the OB and NA had a similar increased body mass index (%), 35% of the NA group always read nutrition labels compared to none in the OB (P < 0.05), and more NA children felt their diet is “less healthy”. NA consumed the least amount of fruits with only 25% having ≥ 1 fruit/d vs 45% in OB and 64.7% in CO (P < 0.05 NA vs CO). Only 15% of NA subjects performed light exercise vs 35% and 59% of OB and CO groups, respectively (P = 0.02). The mean physical activity score was lowest in the NA group (P < 0.05). Amongst the subjects with NASH, we found that 100% of patients with grade 2 or 3 fibrosis had a sedentary score > 2 compared to only 63.6% of those with grade 1 or no fibrosis (P < 0.05).

CONCLUSION: Children with NASH had increased se-dentary behavior, decreased activity, and fruit intake. Larger studies may determine the benefit of changing these behaviors as treatment for NASH.

Noninvasive evaluation of hepatic fibrosis using acoustic radiation force-based shear stiffness in patients with nonalcoholic fatty liver disease

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD), the most common form of chronic liver disease in developed countries, may progress to nonalcoholic steatohepatitis (NASH) in a minority of people. Those with NASH are at increased risk for cirrhosis and hepatocellular carcinoma. The potential risk and economic burden of utilizing liver biopsy to stage NAFLD in an overwhelmingly large at-risk population are enormous; thus, the discovery of sensitive, inexpensive, and reliable noninvasive diagnostic modalities is essential for population-based screening.

METHODS

Acoustic Radiation Force Impulse (ARFI) shear wave imaging, a noninvasive method of assessing tissue stiffness, was used to evaluate liver fibrosis in 172 patients diagnosed with NAFLD. Liver shear stiffness measures in three different imaging locations were reconstructed and compared to the histologic features of NAFLD and AST-to-platelet ratio indices (APRI).

RESULTS

Reconstructed shear stiffnesses were not associated with ballooned hepatocytes (p=0.11), inflammation (p=0.69), nor imaging location (p=0.11). Using a predictive shear stiffness threshold of 4.24kPa, shear stiffness distinguished low (fibrosis stage 0-2) from high (fibrosis stage 3-4) fibrosis stages with a sensitivity of 90% and a specificity of 90% (AUC of 0.90). Shear stiffness had a mild correlation with APRI (R(2)=0.22). BMI>40kg/m(2) was not a limiting factor for ARFI imaging, and no correlation was noted between BMI and shear stiffness (R(2)=0.05).

CONCLUSIONS

ARFI imaging is a promising imaging modality for assessing the presence or absence of advanced fibrosis in patients with obesity-related liver disease.

Transcriptional profile of genes involved in oxidative stress and antioxidant defense in a dietary murine model of steatohepatitis

Oxidative stress is a core abnormality responsible for disease progression in nonalcoholic steatohepatitis (NASH). However, the relevant pathways that contribute to oxidative damage in vivo remain poorly understood. Here we explore the gene-expression patterns related to oxidative stress, antioxidant defense, and reactive oxygen metabolism in an established dietary murine model of NASH. C57BL/6 mice were placed on either a methionine- and choline-deficient (MCD) or a control (CTL) diet for 6 weeks. Hepatic oxidative damage and the development of NASH were monitored by biochemical and histologic indices. Analysis of 84 oxidative stress-related genes was performed by real-time reverse transcription polymerase chain reaction (PCR) in the livers of the two groups of mice. Mice on the MCD diet showed increased ALT, histologic features of NASH, and oxidative liver damage with increases in 4-hydroxynonenal and 3-nitrotyrosine. Of the genes analyzed, the GPx family were most significantly upregulated, whereas SCD1 was most significantly downregulated. Other genes that were significantly upregulated included Fmo2 and peroxiredoxins, whereas genes downregulated included Catalase and Serpinb1b. Our data demonstrate that oxidative stress-related genes are differentially expressed in the livers of mice with diet-induced NASH. These findings have important implications for NASH pathogenesis and the development of novel therapeutic strategies for patients with this condition.

Atherogenic dyslipidemia and cardiovascular risk in children with nonalcoholic fatty liver disease

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.

Anaesthetic considerations for the obese child

The prevalence of obesity in the paediatric population is increasing worldwide. As a result, more and more children will present for anaesthetic care for surgery and other procedures. This review aims to provide some recent information regarding the anaesthetic management of the obese child. Unfortunately, there is little evidence on which to base our clinical care of these children and what information is available is often extrapolated from adult practice. Further prospective studies are required, with careful attention to definitions and terminology, so that populations can be compared and appropriate conclusions drawn.