The metabolic syndrome and nonalcoholic fatty liver disease in children

Metabolic syndrome therapy in pediatric age - between classic and modern. From diets to pipeline drugs

The metabolic syndrome, made up of the sum of the entities that define it (obesity, hypertension, dyslipidemias and non-alcoholic hepatic steatosis) has gained an important place in the research of the last decades. This aspect is mainly due to the complexity of management in pediatric practice. The main directions in his approach therefore bring together the concern of counteracting the noise or systemic, of the multiple intercurrents at the physiopathological level, as well as the negative imprint exerted on the quality of life. Its appearance and evolution are currently controversial topics, but the influence of genetic predisposition and lifestyle (diet, physical activity, psychological balance) are certainties. Considering the escalation of the incident at the global level, it is self-evident that it is necessary to know the pathogenesis and practice countermeasures for prophylactic or therapeutic purposes. The present work aims to summarize general aspects related to the metabolic syndrome encountered in pediatric age, with an emphasis on complementary therapeutic perspectives and their effectiveness, by analyzing the latest data from the specialized literature, accessed with the help of international databases (e.g., PubMed, Web of Science, Scopus, Embase, Google Scholar).

The role of adipocytokines in the development of non-alcoholic fatty liver disease in children and adolescents

Over the past 20 years, the proportion of overweight and obese children and adolescents has increased significantly in most countries. Obesity represents a major cardiometabolic risk and is closely associated with comorbidities such as hypertension, hyperlipidemia, hyperinsulinemia, type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD). There is a lot of uncertainty regarding the diagnosis of metabolic syndrome in children, mainly due to the various and conflicting definitions that have been proposed. The prevalence of metabolic syndrome varied significantly in children (from 6 to 39%) depending on the applied definition criteria. According to these definitions, only 2% of children met all the criteria for metabolic syndrome. Over the past decade, studies have shown that, in parallel with the increase in the prevalence of obesity in the pediatric population, NAFLD has become the most common form of liver disease in childhood. In NAFLD, inflammatory cytokines/adipokines and other factors lead to steatohepatitis and/or fibrosis. Recently, several adipocytokines and inflammatory cytokines have been identified with significant positive (leptin, chemerin, vaspin, TNF-α, IL-6 and IL-8) or negative (adiponectin) associations with metabolic risk factors. Some of them can be considered as pathophysiological factors linking obesity and its complications such as insulin resistance and NAFLD. However, data on other adipocytokines and their role in metabolism remain controversial and partially unknown, especially with regard to their role in childhood (resistin, NAMPT, FGF-21, A-FABP, RBP4, lipocalin-2, omentin-1, hsCRP). Adipocytokines are a novel and powerful tool not only for the diagnosis and stratification of NAFLD and the metabolic syndrome, but also as a potential therapeutic target. Adipocytokine therapy requires further study in all patients with metabolic syndrome and NAFLD, especially in children and adolescents.

The Role of Vitamin D in Obese Children with Non-Alcoholic Fatty Liver Disease and Associated Metabolic Syndrome

Non-alcoholic fatty liver disease (NAFLD) represents a complex chronic condition, which in the absence of screening-monitoring markers and effective standardized treatment is one of the most important issues in pediatric pathology. In this study, we analyzed the role of vitamin D supplementation in obese children with/without NAFLD and the impact on the components of the associated metabolic syndrome (MS). The study included 22 children with simple obesity (SO) and 50 with NAFLD, aged between 6 and 14 years, who received regimen-based therapy or vitamin D supplementation in case of deficiency. Anthropometric and paraclinical data associated with MS were statistically compared before and after treatment. It was observed that there was a statistical association of NAFLD with MS components, which were present both in SO and in the 6-9 years group. Vitamin D deficiency was associated with the presence of obesity, NAFLD and MS components, and correction of the deficiency induced a tendency to normalize the associated parameters. In the case of a treatment strictly based on the regimen, we found decreases in vitamin D values and additional alteration of some parameters. Supplementation with vitamin D potentiates the effects of the specific regimen, and the effects seem to be dependent on the MS components.

Is Metabolic Syndrome Useful for Identifying Youths with Obesity at Risk for NAFLD?

The definition of metabolic syndrome (MetS) in childhood is controversial. Recently, a modified version of the International Diabetes Federation (IDF) definition was proposed using reference data from an international population for high waist circumference (WC) and blood pressure (BP), while the fixed cutoffs for lipids and glucose were not changed. We analyzed MetS prevalence using this modified definition (MetS-IDF_m) and its association with non-alcoholic fatty liver disease (NAFLD) in 1057 youths (age 6-17 years) with overweight/obesity (OW/OB). A comparison with another modified definition of MetS according to the Adult Treatment Panel III (MetS-ATPIII_m) was performed. The prevalence of MetS-IDF_m was 27.8% and 28.9% by MetS-ATPIII_m. The Odds (95% Confidence Intervals) of NAFLD was 2.70 (1.30-5.60) (p = 0.008) for high WC, 1.68 (1.25-2.26)(p = 0.001) for MetS, 1.54 (1.12-2.11)(p = 0.007) for low HDL-Cholesterol, 1.49 (1.04-2.13)(p = 0.032) for high triglycerides and 1.37 (1.03-1.82)(p = 0.033) for high BP. No substantial difference was found in the prevalence of MetS-IDF_m and frequency of NAFLD compared to Mets-ATPIII_m definition. Our data demonstrate that one third of youths with OW/OB have MetS, whichever was the criterion. Neither definition was superior to some of their components in identifying youths with OW/OB at risk for NAFLD.

Association of plasma kynurenine pathway metabolite concentrations with metabolic health risk in prepubertal Asian children

BACKGROUND

The tryptophan-kynurenine (KYN) pathway is linked to obesity-related systemic inflammation and metabolic health. The pathway generates multiple metabolites, with little available data on their relationships to early markers of increased metabolic disease risk in children. The aim of this study was to examine the association of multiple KYN pathway metabolites with metabolic risk markers in prepubertal Asian children.

METHODS

Fasting plasma concentrations of KYN pathway metabolites were measured using liquid chromatography-tandem mass spectrometry in 8-year-old children (n = 552) from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) prospective mother-offspring cohort study. The child's weight and height were used to ascertain overweight and obesity using local body mass index (BMI)-for-age percentile charts. Body fat percentage was measured by quantitative magnetic resonance. Abdominal circumference, systolic and diastolic blood pressure, homeostatic model assessment for insulin resistance (HOMA-IR), triglyceride, and HDL-cholesterol were used for the calculation of Metabolic syndrome scores (MetS). Serum triglyceride, BMI, gamma-glutamyl transferase (GGT), and abdominal circumference were used in the calculation of the Fatty liver index (FLI). Associations were examined using multivariable regression analyses.

RESULTS

In overweight or obese children (n = 93; 16.9% of the cohort), all KYN pathway metabolites were significantly increased, relative to normal weight children. KYN, kynurenic acid (KA), xanthurenic acid (XA), hydroxyanthranilic acid (HAA) and quinolinic acid (QA) all showed significant positive associations with body fat percentage (B(95% CI) = 0.32 (0.22,0.42) for QA), HOMA-IR (B(95% CI) = 0.25 (0.16,0.34) for QA), and systolic blood pressure (B(95% CI) = 0.14(0.06,0.22) for QA). All KYN metabolites except 3-hydroxykynurenine (HK) significantly correlated with MetS (B (95% CI) = 0.29 (0.21,0.37) for QA), and FLI (B (95% CI) = 0.30 (0.21,0.39) for QA).

CONCLUSIONS

Higher plasma concentrations of KYN pathway metabolites are associated with obesity and with increased risk for metabolic syndrome and fatty liver in prepubertal Asian children.

Updates in non-alcoholic fatty liver disease (NAFLD)

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

Maternal diet intervention before pregnancy primes offspring lipid metabolism in liver

Nonalcoholic fatty liver disease (NAFLD) has a developmental origin and is influenced in utero. We aimed to evaluate if maternal diet intervention before pregnancy would be beneficial to reduce the risk of offspring NAFLD. In our study, female mice were either on a normal-fat diet (NF group), or a high-fat diet for 12 weeks and continued on this diet throughout pregnancy and lactation (HF group), or switched from HF-to-NF diet 1 week (H1N group), or 9 weeks (H9N group) before pregnancy. Compared with the NF offspring, the H1N and HF, but not the H9N offspring, displayed more severe hepatic steatosis and glucose intolerance. More specifically, an abnormal blood lipid panel was seen in the H1N offspring and abnormal hepatic free fatty acid composition was present in both the HF and H1N offspring, while the H9N offspring displayed both at normal levels. These physiological changes were associated with desensitized hepatic insulin/AKT signaling, increased expression of genes and proteins for de novo lipogenesis and cholesterol synthesis, decreased expression of genes and proteins for fatty acid oxidation, increased Pcsk9 expression, and hypoactivation of 5' AMP-activated protein kinase (AMPK) signaling in the HF and H1N offspring. However, these effects were completely or partially rescued in the H9N offspring. In summary, we found that early maternal diet intervention is effective in reducing the risk of offspring NAFLD caused by maternal HF diet. These findings provide significant support to develop effective diet intervention strategies and policies for prevention of obesity and NAFLD to promote optimal health outcomes for mothers and children.

Increased liver echogenicity and liver enzymes are associated with extreme obesity, adolescent age and male gender: analysis from the German/Austrian/Swiss obesity registry APV

Background

Childhood obesity is often associated with non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease in pediatrics.

Methods

This multi-center study analyzed liver echogenicity and liver enzymes in relation to obesity, age, gender and comorbidities. Data were collected using a standardized documentation software (APV) from 1.033 pediatric patients (age: 4–18 years, body mass index = BMI: 28–36 kg/m², 50% boys) with overweight (BMI >90th percentile), obesity (BMI >97th percentile) or extreme obesity (BMI > 99.5th percentile) and obesity related comorbidities, especially NAFLD from 26 centers of Germany, Austria and Switzerland. Liver enzymes aspartate aminotransferase (AST), alanine-aminotransferase (ALT) and gamma glutamyltransferase (gammaGT) were evaluated using 2 cut-off values a) > 25 U/L and b) > 50 U/L. Multiple logistic regression models were used for statistical analysis.

Results

In total, 44% of the patients showed increased liver echogenicity. Liver enzymes > 25 U/L were present in 64% and > 50 U/L in 17%. Increased liver echogenicity was associated with elevated liver enzymes (> 25 U/L: odds ratio (OR) = 1.4, 95% CI: 1.1–1.9, P < 0.02; > 50 U/L: OR = 3.5, 95% CI: 2.4–5.1, P < 0.0001). Extreme obesity, adolescence and male gender were associated with increased liver echogenicity (extreme obesity vs overweight OR = 3.5, 95% CI: 1.9–6.1, P < 0.0001; age > 14 years vs age < 9 years OR = 2.2, 95% CI: 1.4–3.5, P < 0.001; boys vs girls OR = 1.6, 95% CI: 1.2–2.0, P < 0.001) and elevated liver enzymes (extreme obesity vs overweight > 25 U/L: OR = 4.1, 95% CI: 2.4–6.9, P < 0.0001; > 50 U/L: OR = 18.5, 95% CI: 2.5–135, P < 0.0001; age > 14 years vs age < 9 years > 50 U/L: OR = 1.9, 95% CI: 1.0–3.7, P > 0.05; boys vs girls > 25 U/L: OR = 3.1, 95% CI: 2.4–4.1, P < 0.0001; > 50 U/L: OR = 2.1, 95% CI: 1.5–2.9, P < 0.0001). Impaired glucose metabolism showed a significant correlation with elevated liver enzymes > 50 U/L (OR = 4.4, 95% CI: 1.6–11.8, P < 0.005). Arterial hypertension seemed to occur in patients with elevated liver enzymes > 25 U/L (OR 1.6, 95% CI: 1.2–2.0, P < 0.005).

Conclusions

NAFLD is strongly related to extreme obesity in male adolescents. Moreover impaired glucose tolerance was observed in patients with elevated liver enzymes > 50 U/L, but arterial hypertension was only present in patients with moderately elevated liver enzymes > 25 U/L.

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

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

Free-breathing 3-D quantification of infant body composition and hepatic fat using a stack-of-radial magnetic resonance imaging technique

BACKGROUND

Body composition and hepatic fat correlate with future risk for metabolic syndrome. In children, many conventional techniques for quantifying body composition and hepatic fat have limitations. MRI is a noninvasive research tool to study body composition and hepatic fat in infants; however, conventional Cartesian MRI is sensitive to motion, particularly in the abdomen because of respiration. Therefore we developed a free-breathing MRI technique to quantify body composition and hepatic fat in infants.

OBJECTIVE

In infants, we aimed to (1) compare the image quality between free-breathing 3-D stack-of-radial MRI (free-breathing radial) and 3-D Cartesian MRI in the liver and (2) determine the feasibility of using free-breathing radial MRI to quantify body composition and hepatic proton-density fat fraction (PDFF).

MATERIALS AND METHODS

Ten infants ages 2-7 months were scanned with free-breathing radial (two abdominal; one head and chest) and Cartesian (one abdominal) MRI sequences. The median preparation and scan times were reported. To assess feasibility for hepatic PDFF quantification, a radiologist masked to the MRI technique scored abdominal scans for motion artifacts in the liver using a 3-point scale (1, or non-diagnostic, to 3, or no artifacts). Median visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and brown adipose tissue (BAT) volume and PDFF, and hepatic PDFF were measured using free-breathing radial MRI. We assessed repeatability of free-breathing radial hepatic PDFF (coefficient of repeatability) between back-to-back scans. We determined differences in the distribution of image-quality scores using McNemar-Bowker tests. P<0.05 was considered significant.

RESULTS

Nine infants completed the entire study (90% completion). For ten infants, the median preparation time was 32 min and scan time was 24 min. Free-breathing radial MRI demonstrated significantly higher image-quality scores compared to Cartesian MRI in the liver (radial scan 1 median = 2 and radial scan 2 median = 3 vs. Cartesian median = 1; P=0.01). Median measurements using free-breathing radial were VAT=52.0 cm³, VAT-PDFF=42.2%, SAT=267.7 cm³, SAT-PDFF=87.1%, BAT=1.4 cm³, BAT-PDFF=26.1% and hepatic PDFF=3.4% (coefficient of repeatability <2.0%).

CONCLUSION

In this study, free-breathing radial MRI in infants achieved significantly improved liver image quality compared to Cartesian MRI. It is feasible to use free-breathing radial MRI to quantify body composition and hepatic fat in infants.

Liver Fat Content and Body Fat Distribution in Youths with Excess Adiposity

This study had two main objectives: To examine the association between body fat distribution and non-alcoholic fatty liver disease (NAFLD) and liver fat content, and to determine whether the relationship between NAFLD and regional body fat distribution, with respect to liver fat content in youths with excess adiposity, is independent of cardiorespiratory fitness (CRF) and a healthy diet. Liver fat content (controlled attenuation parameter (CAP)), body fat distribution (body mass index (BMI) z-score, waist circumference, waist-to-height ratio, fat mass/height, body fat percentage, total fat mass, android-to-gynoid fat mass ratio, visceral adipose tissue (VAT), and lean mass index, determined by dual-energy X-ray absorptiometry (DXA)), CRF (20-m shuttle-run test), and healthy diet (adherence to the Mediterranean diet by KIDMED questionnaire) were measured in 126 adolescents (66% girls) aged between 11 and 17 years. Participants were assigned to two groups according to the presence or absence of hepatic steatosis (CAP values ≥225 dB/m or <225 dB/m of liver fat, respectively). Considering the similar total fat values for the two groups (>30% by DXA), youths with NAFLD had higher fat distribution parameters than those without NAFLD, regardless of sex, age, puberty stage, lean mass index, CRF, and healthy diet (p < 0.01). In the non-NAFLD group, the association between hepatic fat and fat distribution parameters presented a similar pattern, although the association was statistically insignificant after adjusting for a potential confounding variable (ps > 0.05), except for the case of VAT. Body fat distribution parameters were higher in youths with NAFLD compared to those without NAFLD. Additionally, body fat distribution showed a significant association with liver fat content as assessed by CAP in youths with NAFLD independent of CRF and adherence to the Mediterranean diet, supporting the notion that upper body fat distribution might play a pivotal role in the development of NAFLD in adolescents. These results may have implications for the clinical management of youths with excess adiposity given the high prevalence of NAFLD in children and young adults.

Novel Insights in the Metabolic Syndrome in Childhood and Adolescence

Metabolic syndrome (MetS) is recognized as an escalating major health risk in adults as well as in children and adolescents. Its prevalence ranges from 6 to 39% depending on the applied definition criteria. To date, there is no consensus on a MetS definition for children and adolescents. However, most authors agree on essential components such as glucose intolerance, central obesity, hypertension, and dyslipidemia; each representing a risk for cardiovascular disease. Recently, associations between MetS and non-alcoholic fatty liver disease, hyperuricemia, and sleep disturbances have emerged. Biomarkers like adipocytokines are a subject of current research as they are implicated in the pathogenesis of the MetS. Epigenetics and gestational programming, especially the role of microRNA, comprise a novel, rapidly developing and promising research focus on the topic of MetS. MicroRNAs are increasingly valued for potential roles in the diagnosis, stratification, and therapeutics of MetS. Early detection of risk factors, screening for metabolic disturbances, and the identification of new therapies are major aims to reduce morbidity and mortality related to MetS. Dietary modification and physical activity are currently the only adopted treatment approaches. Pharmacological therapies and bariatric surgery are still contradictory and, therefore, are only recommended in selected high-risk cases.

High circulatory leptin mediated NOX-2-peroxynitrite-miR21 axis activate mesangial cells and promotes renal inflammatory pathology in nonalcoholic fatty liver disease

High circulatory insulin and leptin followed by underlying inflammation are often ascribed to the ectopic manifestations in non-alcoholic fatty liver disease (NAFLD) but the exact molecular pathways remain unclear. We have shown previously that CYP2E1-mediated oxidative stress and circulating leptin in NAFLD is associated with renal disease severity. Extending the studies, we hypothesized that high circulatory leptin in NAFLD causes renal mesangial cell activation and tubular inflammation via a NOX2 dependent pathway that upregulates proinflammatory miR21. High-fat diet (60% kcal) was used to induce fatty liver phenotype with parallel insulin and leptin resistance. The kidneys were probed for mesangial cell activation and tubular inflammation that showed accelerated NASH phenotype and oxidative stress in the liver. Results showed that NAFLD kidneys had significant increases in α-SMA, a marker of mesangial cell activation, miR21 levels, tyrosine nitration and renal inflammation while they were significantly decreased in leptin and p47 phox knockout mice. Micro RNA21 knockout mice showed decreased tubular immunotoxicity and proinflammatory mediator release. Mechanistically, use of NOX2 siRNA or apocynin,phenyl boronic acid (FBA), DMPO or miR21 antagomir inhibited leptin primed-miR21-mediated mesangial cell activation in vitro suggesting a direct role of leptin-mediated NOX-2 in miR21-mediated mesangial cell activation. Finally, JAK-STAT inhibitor completely abrogated the mesangial cell activation in leptin-primed cells suggesting that leptin signaling in the mesangial cells depended on the JAK-STAT pathway. Taken together the study reports a novel mechanistic pathway of leptin-mediated renal inflammation that is dependent on NOX-2-miR21 axis in ectopic manifestations underlying NAFLD-induced co-morbidities.

Decreased eating frequency linked to increased visceral adipose tissue, body fat, and BMI in Hispanic college freshmen

Background

To investigate the relationship between eating frequency and specific adiposity markers in a potentially high-risk and understudied population of Hispanic college freshmen.

Methods

This study included 92 Hispanic college freshmen (18–19 y). The following cross-sectional data were collected: height, weight, waist circumference, body mass index (BMI), dietary intake, body composition, physical activity, hepatic fat, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT).

Results

Infrequent eaters ate 44% less often (2.5 ± 0.2 vs. 4.5 ± 0.8, p ≤ 0.01) and consumed 27% more calories per EO (p ≤ 0.01), while consuming 21% less kcals per day (p ≤ 0.01) compared to frequent eaters. Infrequent eaters had 8% higher BMIs (24.8 ± 4.4 vs. 22.9 ± 3.2 kg/m²) (p = 0.02), 60% higher BMI z-scores (0.5 ± 1.0 vs. 0.2 ± 1.0, p = 0.03), 21% higher VAT (298.3 ± 153.8 vs. 236.8 ± 78.2 ml, p = 0.03), 26% higher SAT (1150.1 ± 765.4 vs. 855.6 ± 494.6 ml, p = 0.03), and 8% higher total body fat (27.6 ± 10.8 vs. 25.3 ± 8.8%, p = 0.04) compared to frequent eaters while showing no significant difference in physical activity. These findings seem to be driven by females more than males.

Conclusions

These findings suggest that infrequent eating is related to increased adiposity in Hispanic college freshmen, despite a decreased daily energy intake and no significant differences in physical activity. Yet, more research is needed to understand the underlying mechanisms of these findings, as well as investigate any potential causal relationship between eating frequency and adiposity in Hispanic youth.

Investigation of Clinical and Pathological Relationships between Adult- and Pediatric-type NASH in Korean Children

BACKGROUND

Histologically, nonalcoholic steatohepatitis (NASH) is categorized into adult-type (type 1) and pediatric-type (type 2). The origination of the histological difference between the two types and how they differ clinically remain uncertain. We aimed to understand the incidence and clinical characteristics of the two types of NASH in Korean children, and to investigate the association between their pathological type and clinical characteristics, using anthropometric and laboratory data.

METHODS

In 38 children with confirmed NASH, we investigated hepatic pathological findings, and correlating factors between pathological type and laboratory and anthropometric data (weight percentile, body mass index (BMI) z-score, and blood pressure percentile). Adult-type NASH was noted in 21 patients and pediatric-type in 17 patients.

RESULTS

Age, sex, BMI, transaminase levels, and insulin resistance were not significantly different between the two groups. Triglyceride (TG) levels were higher in adult-type NASH (P = 0.033). Hematocrit and albumin levels were lower in adult-type NASH (P = 0.016 and 0.013, respectively). Hepatic fibrosis was more common in pediatric-type. The fibrosis scores in patients with adult-type were mostly 0 and 1, whereas the score was 3 in patients with pediatric-type (P = 0.024, 0.004, and < 0.010, respectively). Anthropometric data, liver function, and insulin resistance scores did not differ between the two pathological NASH types. TG, hematocrit, and albumin may be potential factors to predict pathological types. Fibrosis was observed more frequently in pediatric-type NASH.

CONCLUSION

Monitoring children with pediatric-type NASH for progression to fibrosis or cirrhosis is recommended.

Shear-wave ultrasound elastography of the liver in normal-weight and obese children

Background The identification and subsequent management of liver diseases in children is challenging due to the lack of non-invasive imaging biomarkers. Ultrasound shear-wave elastography (US-SWE) is an emerging imaging technique which can quantitatively assess liver stiffness and may be useful as a tool in the management of liver disease in overweight and obese children. Purpose To evaluate US-SWE velocities of the liver in normal-weight and obese children, to correlate US-SWE findings with age and body-mass-index (BMI), and to compare US-SWE values with qualitative assessment (i.e. normal versus abnormal echogenicity) of the liver by conventional US. Material and Methods A cohort of 300 children (mean age, 9.9 ± 5.3 years; age range, 0.06-18.9 years) were studied, comprising 176 normal-weight and 124 obese participants. In each patient, both US-SWE and conventional US of the liver were obtained. Three pediatric radiologists individually and in consensus determined whether liver parenchyma was of normal or abnormal echogenicity. Results US-SWE velocities differed between normal-weight and obese children (1.08 ± 0.14 versus 1.44 ± 0.39 m/s; P < 0.001), but not by gender. Multivariate linear regression demonstrated US-SWE velocity to be primarily associated with age in normal-weight children ( P < 0.05) and with BMI in obese children ( P < 0.001). In the obese group, mean US-SWE velocity was statistically higher in participants with abnormal echogenic livers than in those with normal-appearing livers (1.53 ± 0.38 vs. 1.17 ± 0.27). The difference was not significant in the normal-weight group. Conclusion US-SWE provides a useful quantitative imaging biomarker for evaluating liver stiffness in children.

Pediatric Metabolic Syndrome: Pathophysiology and Laboratory Assessment

Pediatric overweight and obesity is an emerging public health priority as rates have rapidly increased worldwide. Obesity is often clustered with other metabolic abnormalities including hypertension, dyslipidemia, and insulin resistance, leading to increased risk of cardiovascular disease. This cluster of risk factors, termed the metabolic syndrome, has traditionally been reported in adults. However, with the increased prevalence of pediatric obesity, the metabolic syndrome is now evident in children and adolescents. This complex cluster of risk factors is the result of the pathological interplay between several organs including adipose tissue, muscle, liver, and intestine with a common antecedent - insulin resistance. The association of the metabolic syndrome with several systemic alterations that involve numerous organs and tissues adds to the complexity and challenge of diagnosing the metabolic syndrome and identifying useful clinical indicators of the disease. The complex physiology of growing and developing children and adolescents further adds to the difficulties in standardizing laboratory assessment, diagnosis, and prognosis for the diverse pediatric population. However, establishing a consensus definition is critical to identifying and managing children and adolescents at high risk of developing the metabolic syndrome. As a result, the examination of novel metabolic syndrome biomarkers which can detect these metabolic abnormalities early with high specificity and sensitivity in the pediatric population has been of interest. Understanding this complex cluster of risk factors in the pediatric population is critical to ensure that this is not the first generation where children have a shorter life expectancy than their parents. This review will discuss the pathophysiology, consensus definitions and laboratory assessment of pediatric metabolic syndrome as well as potential novel biomarkers.

Hepatic Retinyl Ester Hydrolases and the Mobilization of Retinyl Ester Stores

For mammals, vitamin A (retinol and metabolites) is an essential micronutrient that is required for the maintenance of life. Mammals cannot synthesize vitamin A but have to obtain it from their diet. Resorbed dietary vitamin A is stored in large quantities in the form of retinyl esters (REs) in cytosolic lipid droplets of cells to ensure a constant supply of the body. The largest quantities of REs are stored in the liver, comprising around 80% of the body’s total vitamin A content. These hepatic vitamin A stores are known to be mobilized under times of insufficient dietary vitamin A intake but also under pathological conditions such as chronic alcohol consumption and different forms of liver diseases. The mobilization of REs requires the activity of RE hydrolases. It is astounding that despite their physiological significance little is known about their identities as well as about factors or stimuli which lead to their activation and consequently to the mobilization of hepatic RE stores. In this review, we focus on the recent advances for the understanding of hepatic RE hydrolases and discuss pathological conditions which lead to the mobilization of hepatic RE stores.

Serum vascular endothelial cadherin and thrombomodulin are markers of non-alcoholic fatty liver disease in children

BACKGROUND

The diagnosis of non-alcoholic fatty liver disease (NAFLD) is usually based on liver ultrasonography and serum alanine aminotransferase (ALT) levels. However, the serum ALT level is not sensitive for detecting NAFLD. If more serum markers are available, serum analysis may play a more important role in the diagnosis of NAFLD.

METHODS

Here, we have investigated whether vascular endothelial cadherin (VE-cad) and thrombomodulin (TM) are markers of NAFLD in children. After an examination of liver ultrasonography, 90 children were divided into a lean control group (n=32), an overweight/obese NAFLD group (group-NAFLD, n=34) and an overweight/obese non-NAFLD group (group-SOO, n=24).

RESULTS

Two overweight/obese groups had similar obesity. However, serum VE-cad and TM levels were increased in group-NAFLD but not group-SOO. When data from all children were pooled, serum VE-cad and TM levels were positively correlated to body-mass index (BMI) and serum ALT levels.

CONCLUSIONS

In conclusion, VE-cad and TM are markers of pediatric NAFLD.

Metabolic syndrome, hepatic steatosis, and cardiovascular risk in children

OBJECTIVES

Pediatric metabolic syndrome (MetS) is a well-recognized entity; however, there is no consensus on its exact value in predicting long-term cardiovascular (CV) risk. Hepatic steatosis (HS) is another emerging condition associated with pediatric obesity, and data have been reported suggesting a possible role of HS in CV risk linked to MetS. The aim of the present study was to evaluate the usefulness of HS and MetS cluster in predicting CV risk linked to pediatric obesity.

METHODS

We studied 803 overweight and obese children (395 girls and 408 boys, mean age 9.4 ± 2.5 y, body mass index z-score 2.2 ± 0.53) with complete clinical and biological assessment. MetS was defined using the modified criteria of the American Heart Association. The diagnosis and severity of the HS was based on ultrasound. To assess CV risk, all patients underwent ultrasonography to measure carotid intima-media thickness (cIMT)-a validated marker of subclinical vascular disease.

RESULTS

The overall prevalence of MetS was 13.07%; HS was significantly higher in patients with MetS (40.9 versus 18.5%; P < 0.001; odds ratio, 3.059; 95% confidence interval, 1.98-4.7). Spearman's correlation between HS grade and the number of MetS criteria met by each patient was significant (r = 0.285; P < 0.001). No statistical difference was recorded in cIMT and cIMT z-scores between patients with or without MetS, until inclusion of HS as an additional criterion for the diagnosis of MetS. In this case, there was a significant difference in cIMT z-scores between the two groups. In multiple linear regression analysis, the cIMT z-score value was better predicted with HS grade and the MetS cluster (adjusted R² = 2.6%; P = 0.002) than when using the MetS cluster only.

CONCLUSIONS

HS could be used as additional criterion in detecting pediatric MetS phenotype at higher risk for long-term CV morbidity.

Clinical significance of serum alanine aminotransferase and lifestyle intervention in children with nonalcoholic fatty liver disease

Purpose

This study aimed to investigate the clinical significance of serum alanine aminotransferase (ALT) levels in children with nonalcoholic fatty liver disease (NAFLD) and the effect of lifestyle intervention on NAFLD.

Methods

The clinical data of 86 children diagnosed with NAFLD were reviewed retrospectively. Forty-six patients belonged to the elevated ALT group and 40 to the normal ALT group. The clinical parameters of patients with NAFLD were also compared based on the status of ALT levels after lifestyle intervention.

Results

Patients with elevated ALT had significantly higher body mass index (BMI) scores than those with normal ALT (P<0.05). Of all the patients with elevated ALT, 89% exhibited moderate or severe degree of fatty change in the liver on ultrasonographic examination, whereas most patients with normal ALT exhibited mild or moderate degree changes. Liver biopsy was performed in 15 children with elevated ALT and all showed mild histological changes. Of all patients with elevated ALT, 49% achieved normal ALT levels after lifestyle intervention. Those with more severe histological changes tended to have continuously increasing ALT levels. There was no correlation between the normalization of posttreatment ALT level and BMI, as well as ultrasonographic findings at diagnosis.

Conclusion

ALT elevation in NAFLD is highly associated with higher BMI scores and more severe degree of fatty changes on ultrasonographic examination. Lifestyle intervention can significantly improve ALT in children with NAFLD. The degree of histologic changes appears to be a predictor of the treatment response to NAFLD.

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.

Fifty Years of Technological Innovation: Potential and Limitations of Current Technologies in Abdominal Magnetic Resonance Imaging and Computed Tomography

Magnetic resonance imaging (MRI) has become an important modality for the diagnosis of intra-abdominal pathology. Hardware and pulse sequence developments have made it possible to derive not only morphologic but also functional information related to organ perfusion (dynamic contrast-enhanced MRI), oxygen saturation (blood oxygen level dependent), tissue cellularity (diffusion-weighted imaging), and tissue composition (spectroscopy). These techniques enable a more specific assessment of pathologic lesions and organ functionality. Magnetic resonance imaging has thus transitioned from a purely morphologic examination to a modality from which image-based disease biomarkers can be derived. This fits well with several emerging trends in radiology, such as the need to accurately assess response to costly treatment strategies and the need to improve lesion characterization to potentially avoid biopsy. Meanwhile, the cost-effectiveness, availability, and robustness of computed tomography (CT) ensure its place as the current workhorse for clinical imaging. Although the lower soft tissue contrast of CT relative to MRI is a long-standing limitation, other disadvantages such as ionizing radiation exposure have become a matter of public concern. Nevertheless, recent technical developments such as dual-energy CT or dynamic volume perfusion CT also provide more functional imaging beyond morphology.The aim of this article was to review and discuss the most important recent technical developments in abdominal MRI and state-of-the-art CT, with an eye toward the future, providing examples of their clinical utility for the evaluation of hepatic and renal pathologies.

The association between retinal microvascular changes, metabolic risk factors, and liver histology in pediatric patients with non-alcoholic fatty liver disease (NAFLD)

BACKGROUND

The prevalence of childhood obesity is increasing worldwide. Studies in adult populations show that retinal microvascular changes are associated with obesity and components of the metabolic syndrome. In our study we have assessed the effect of body mass index (BMI), metabolic parameters, and adiposity on the retinal microvasculature in children.

METHODS

Fifty-four consecutive children with biopsy-proven NAFLD were enrolled in this study. Anthropometric and laboratory parameters were obtained using standardized protocols. Retinal caliber was quantified from digital retinal images using well-known computer-based programs. Twenty-four-hour ambulatory blood pressure monitoring was measured using a standard protocol.

RESULTS

In our population, the prevalence of retinopathy was of 53 % (13 males). The 29 patients with retinopathy (mean age 10.91 ± 3.10) showed significantly higher values of triglycerides (mg/day) (105.57 vs. 90.20, p = 0.04), basal insulin (mUI/ml) (17.20 vs. 12.97, p = 0.02), and HOMA-IR (3.37 vs. 2.76, p = 0.04). The patients with a HOMA-IR >2.5 (OR = 3.34, p = 0.02; 95 % IC, 1.07-10.39), and systolic non-dipping (OR 4.16, p = 0.028, 95 % IC, 1.11-13.67), have an increased risk of retinopathy. Moreover, the study of correlation between all stages of liver biopsy (CRN criteria) and the grade of retinopathy showed a positive correlation with fibrosis (r = 0.31) and an NAS score (r = 0.28).

CONCLUSIONS

We found an association between metabolic parameters and nocturnal blood pressure on the retinal microvasculature among the obese children with NAFLD. Furthermore, for the first time, we report the positive relationship between hepatic fibrosis in pediatric NAFLD patients and the degree of retinopathy signs.

The value of different insulin resistance indices in assessment of non-alcoholic fatty liver disease in overweight/obese children

OBJECTIVE

The aim of the present study was to determine the association between insulin resistance (IR) and both non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS) in a group of Egyptian overweight/obese children and adolescents and to evaluate different IR indices in detection of NAFLD.

PATIENTS AND METHODS

The study included 76 overweight/obese children aged 2-15 years; 52.6% were males. Laboratory analysis included fasting blood glucose, serum insulin, lipid profile, liver biochemical profile, and liver ultrasound. IR was calculated using the following indices; the homeostasis model assessment method (HOMA-IR), the quantitative insulin-sensitivity check index (QUICKI) and hepatic insulin sensitivity. The National Cholesterol Education Program Adult Treatment Panel III criteria were used to estimate prevalence of MetS. Liver biopsy was done when medically indicated and accepted by parents.

RESULTS

IR was detected in 43.4% and 34.2% by using QUICKI and HOMA, respectively. MetS was detected in 36.8% and NAFLD was detected in 45.5% among those performing liver biopsy. Cases with NAFLD had more frequent IR than children with normal histology. QUICKI showed significant difference between normal subjects and both steatosis and non-alcoholic steatohepatitis; while HOMA-IR was sensitive in cases with NASH only. MetS was present in 100% of patients with NASH and in 75% of those with steatosis and they were all obese. Patients with NASH had significantly higher ALT than those with normal histology.

CONCLUSION

IR was significantly associated with NAFLD. QUICKI is considered more sensitive than HOMA-IR in differentiating simple steatosis from normal liver histology.

Early-postnatal changes in adiposity and lipids profile by transgenerational developmental programming in swine with obesity/leptin resistance

Maternal malnutrition during pregnancy, both deficiency and excess, induces changes in the intrauterine environment and the metabolic status of the offspring, playing a key role in the growth, status of fitness/obesity and appearance of metabolic disorders during postnatal life. There is increasing evidence that these effects may not be only limited to the first generation of descendants, the offspring directly exposed to metabolic challenges, but to subsequent generations. This study evaluated, in a swine model of obesity/leptin resistance, the existence and extent of transgenerational developmental programming effects. Pre- and postnatal development, adiposity and metabolic features were assessed in the second generation of piglets, descendant of sows exposed to either undernutrition or overnutrition during pregnancy. The results indicated that these piglets exhibited early-postnatal increases in adiposity and disturbances in lipid profiles compatible with the early prodrome of metabolic syndrome, with liver tissue also displaying evidence of paediatric liver disease. These features indicative of early-life metabolic disorders were more evident in the males that were descended from overfed grandmothers and during the transition from milk to solid feeding. Thus, this study provides evidence supporting transgenerational developmental programming and supports the necessity for the development of strategies for avoiding the current epidemics of childhood overweight and obesity.

Predicting hepatic steatosis in a racially and ethnically diverse cohort of adolescent girls

OBJECTIVE

To develop a risk assessment model for early detection of hepatic steatosis using common anthropometric and metabolic markers.

STUDY DESIGN

This was a cross-sectional study of 134 adolescent and young adult females, age 11-22 years (mean 13.3±2 years) from a middle school and clinics in Madison, Wisconsin. The ethnic distribution was 27% Hispanic and 73% non-Hispanic; the racial distribution was 64% Caucasian, 31% African-American, and 5% Asian, Fasting glucose, fasting insulin, alanine aminotransferase (ALT), body mass index (BMI), waist circumference (WC), and other metabolic markers were assessed. Hepatic fat was quantified using magnetic resonance imaging proton density fat fraction (MR-PDFF). Hepatic steatosis was defined as MR-PDFF>5.5%. Outcome measures were sensitivity, specificity, and positive predictive value (PPV) of BMI, WC, ALT, fasting insulin, and ethnicity as predictors of hepatic steatosis, individually and combined, in a risk assessment model. Classification and regression tree methodology was used to construct a decision tree for predicting hepatic steatosis.

RESULTS

MR-PDFF revealed hepatic steatosis in 16% of subjects (27% overweight, 3% nonoverweight). Hispanic ethnicity conferred an OR of 4.26 (95% CI, 1.65-11.04; P=.003) for hepatic steatosis. BMI and ALT did not independently predict hepatic steatosis. A BMI>85% combined with ALT>65 U/L had 9% sensitivity, 100% specificity, and 100% PPV. Lowering the ALT value to 24 U/L increased the sensitivity to 68%, but reduced the PPV to 47%. A risk assessment model incorporating fasting insulin, total cholesterol, WC, and ethnicity increased sensitivity to 64%, specificity to 99% and PPV to 93%.

CONCLUSION

A risk assessment model can increase specificity, sensitivity, and PPV for identifying the risk of hepatic steatosis and guide the efficient use of biopsy or imaging for early detection and intervention.

Pediatric fatty liver disease: role of ethnicity and genetics

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

Nonalcoholic Fatty liver disease/non-alcoholic steatohepatitis in childhood: endocrine-metabolic "mal-programming"

CONTEXT

Nonalcoholic Fatty Liver Disease (NAFLD) is the major chronic liver disease in the pediatric population. NAFLD includes a broad spectrum of abnormalities (inflammation, fibrosis and cirrhosis), ranging from accumulation of fat (also known as steatosis) towards non-alcoholic steatohepatitis (NASH). The development of NAFLD in children is significantly increased.

EVIDENCE ACQUISITION

A literature search of electronic databases was undertaken for the major studies published from 1998 to today. The databases searched were: PubMed, EMBASE, Orphanet, Midline and Cochrane Library. We used the key words: "non-alcoholic fatty liver disease, children, non-alcoholic steatohepatitis and fatty liver".

RESULTS

NAFLD/NASH is probably promoted by "multiple parallel hits": environmental and genetic factors, systemic immunological disorders (oxidative stress, persistent-low grade of inflammation) as well as obesity and metabolic alterations (insulin resistance and metabolic syndrome). However its exact cause still underdiagnosed and unknown.

CONCLUSIONS

Pediatric NAFLD/NASH is emerging problem. Longitudinal follow-up studies, unfortunately still insufficient, are needed to better understand the natural history and outcome of NAFLD in children. This review focuses on the current knowledge regarding the epidemiology, pathogenesis, environmental, genetic and metabolic factors of disease. The review also highlights the importance of studying the underlying mechanisms of pediatric NAFLD and the need for complete and personalized approach in the management of NAFLD/NASH.

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

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

Serum adiponectin, leptin, resistin and RBP4 levels in obese and metabolic syndrome children with nonalcoholic fatty liver disease

AIM

To investigate the relationship of adiponectin, leptin, resistin and RBP4 levels in obese and metabolic syndrome children with nonalcoholic fatty liver disease (NAFLD).

PATIENTS & METHODS

Group I consisted of 63 obese children with liver steatosis, group II consisted of 12 obese children with elevated serum ALT activity from group I, and group III included 85 obese children without liver steatosis.

RESULTS

Leptin levels were higher in the NAFLD children than in the control group. Serum RBP4 levels in obese children with NAFLD were higher than those in obese children without NAFLD and controls. Adiponectin and resistin levels were negatively correlated and RBP4 levels positively correlated with ALT activity and ultrasonographic grading.

CONCLUSION

These data suggest that adiponectin, resistin and RBP4 may have a role in the pathogenesis of NAFLD in obese children. Adiponectin, leptin, resistin and RBP4 may be suitable markers for predicting metabolic syndrome and NAFLD.

The Impacts of Obesity and Metabolic Abnormality on Carotid Intima-Media Thickness and Non-Alcoholic Fatty Liver Disease in Children from an Inland Chinese City

The Chinese inland, where low child obesity and overweight rates were reported in earlier studies, has recently experienced rapid economy changes. This may impact children’s health. In the present study, we investigated the obesity rate, metabolic health status, and their impacts on carotid intima-media thickness (IMT) and non-alcoholic fatty liver disease (NAFLD) among children from Yueyang, an inland city of China. We found that the obesity rate was about 5% for both 7- and 11-year olds. Overweightness rates were 9.5% and 11.5% for the 7- and 11-year olds, respectively. Clinical and laboratory examinations revealed significant differences among different weight groups in the 11-year old volunteers, which were absent in the 7-year olds. Further statistical analysis showed that: age, BMI, blood pressure, triglyceride level, and metabolic abnormality were positively correlated to carotid IMT; triglyceride level, obesity, male, and the number of metabolic abnormalities were independent risk factors for NAFLD in these children. Our study suggests that: childhood overweightness and obesity are now epidemic in Yueyang, which have contributed to increased carotid IMT and may also increased NAFLD incidents; and serum triglyceride level is a critical factor in the development of childhood NAFLD. Thus, childhood metabolic health warrants further vigorous research in the inland of China.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Developmental origins of nonalcoholic fatty liver disease

Obese pregnant women may transmit their metabolic phenotype to offspring, leading to a cycle of obesity and diabetes over generations. Early childhood obesity predicts nonalcoholic fatty liver disease (NAFLD), the most common chronic human liver disease. The fetus may be vulnerable to steatosis because immature fetal adipose depots are not available to buffer the excess transplacental lipid delivery in maternal obesity. In animal models, in utero high-fat diet exposure results in an increase in the accumulation of liver triglycerides in offspring and increased hepatic oxidative stress and apoptosis, perhaps priming the liver for later development of NAFLD. Innate immune dysfunction and necroinflammatory changes have been observed in postnatal offspring liver of animals born to high-fat-fed dams. Postweaning, livers of offspring exposed to maternal high-fat feeding in utero share pathophysiologic features with human NAFLD, including increased de novo lipogenesis and decreased free fatty acid oxidation. Human studies using magnetic resonance imaging have shown that maternal BMI predicts infant intrahepatocellular lipid storage, as seen in animal models. The generational transfer of NAFLD may occur via epigenetic changes in offspring liver. Transmission of microbiota from mother to infant may impact energy retention and immune function that contribute to a predisposition to NAFLD.

Association between UCP3 gene polymorphisms and nonalcoholic fatty liver disease in Chinese children

AIM: To confirm the hypothesis that polymorphisms of the uncoupling protein 3 (UCP3) gene are associated with the occurrence of nonalcoholic fatty liver disease (NAFLD).

METHODS: A total of 250 NAFLD patients (147 males and 103 females) and 200 healthy individuals who served as controls (control, 109 males and 91 females), aged between 6 and 16 years were enrolled in this study. The four non-synonymous single nucleotide polymorphisms (SNPs) in the UCP3 gene polymorphisms of rs1726745, rs3781907, rs11235972 and rs1800849, were genotyped using MassArray. Body mass index (BMI), waist and hip circumference, blood pressure (BP), fasting blood glucose (FBG), insulin and lipid profiles were measured and B-ultrasound examination was performed in all subjects.

RESULTS: NAFLD patients showed risk factors for metabolic syndrome: elevated BMI, waist-to-hip ratio, BP, FBG, homeostasis model assessment-estimated insulin resistance, total triglyceride, total cholesterol and low-density lipoprotein-cholesterol, while decreased high-density lipoprotein-cholesterol level compared with the control group. The GG genotype distributions of rs11235972 in the NAFLD group differed significantly from that in the control group. We found that waist circumference between CC (58.76 ± 6.45 cm) and CT+TT (57.00 ± 5.59 cm), and hip circumference between CC (71.28 ± 7.84 cm) and CT+TT genotypes (69.06 ± 7.75 cm) were significantly different with and without rs1800849 variation (P < 0.05).

CONCLUSION: A higher prevalence of rs11235972 GG genotype was observed in the NAFLD group compared with the control group. No differences were observed for the other SNPs. However, there was a significant difference in body height in addition to waist and hip circumference between the CC (mutant type group) and CT+TT group with and without rs1800849 variation.

Intra-abdominal fat is related to metabolic syndrome and non-alcoholic fat liver disease in obese youth

BACKGROUND

Previous studies have shown an association between adiposity, especially intra-abdominal adipose tissue, and hemodynamic/metabolic comorbidities in adults, however it is not clear in pediatric population. The aim of the study was to analyze the relationship between non-alcoholic fatty liver disease (NAFLD) and components of metabolic syndrome (MS) with values of intra-abdominal (IAAT) and subcutaneous (SCAT) adipose tissue in obese children and adolescents.

METHODS

Cross-sectional study.

SUBJECTS

182 obese sedentary children and adolescents (aged 6 to 16 y), identified by the body mass index (BMI).

MEASUREMENTS

Body composition and trunk fat by dual-energy X-ray absorptiometry- DXA; lipid profile, blood pressure and pubertal stage were also assessed. NAFLD was classified as absent (0), mild (1), moderate (2) and severe (3), and intra-abdominal and subcutaneous abdominal fat thickness were identified by ultrasound. The MS was identified according to the cut offs proposed by World Health Organization adapted for children and adolescents. The chi-square test was used to compare categorical variables, and the binary logistic regression indicated the magnitude of the associations adjusted by potential cofounders (sex, age, maturation, NAFLD and HOMA-IR).

RESULTS

Higher quartile of SCAT was associated with elevated blood pressure (p = 0.015), but not associated with NAFLD (p = 0.665). Higher IAAT was positively associated with increased dyslipidemia (p = 0.001), MS (p = 0.013) and NAFLD (p = 0.005). Intermediate (p = 0.007) and highest (p = 0.001) quartile of IAAT were also associated with dyslipidemia, independently of age, sex, maturation, NAFLD and HOMA-IR (homeostatic model assessment-insulin resistance).

CONCLUSION

Obese children and adolescents, with higher IAAT are more prone to develop MS and NAFLD than those with higher values of SCAT, independent of possible confounding variables.

A 360-degree overview of paediatric NAFLD: recent insights

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

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

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

Role of fats in the first two years of life as related to later development of NCDs

AIMS

Compared to exclusive breastfeeding, the introduction of solids leads to a reduction of dietary fats. We explore the hypothesis that dietary fats consumed in the 6-24-month period might have later effects on non-communicable disorders and health.

DATA SYNTHESIS

We have considered studies on dietary fats as substrate for oxidation and energy production, effects on adiposity, blood lipoprotein levels and features of the metabolic syndrome, and the possible influences on brain development and function. Fat oxidation, despite a high initial dietary supply, is greatly suppressed and only gradually increases after birth. There is no evidence of any convincing association between fat intake during the 6-24-month period and later indices of adiposity. Fat quality may affect the blood lipoprotein picture at short-term through the first 12 months of life. In a large Finnish trial, a moderately restricted fat diet started at 7 months, with an increased unsaturated/saturated fat ratio, has shown favourable effects on serum cholesterol values, indices of insulin resistance and endothelial function especially in boys, and had no negative effects until the age of 18 years. The dietary supply of docosahexaenoic acid might affect brain development as well as some features of the metabolic syndrome.

CONCLUSIONS

In the 6-24-month period, the amount of fat intake does not show associations with later health conditions, and relatively high-fat diets do not seem to be harmful. Fat quality may have later effects on chronic-degenerative processes that need to be explored more in depth.

Pre- and postoperative imaging of adolescents undergoing laparoscopic adjustable gastric banding surgery

BACKGROUND

As childhood obesity rates rise, laparoscopic adjustable gastric banding (LAGB) is being investigated as a bariatric surgical option in adolescents.

OBJECTIVE

To examine pre- and postoperative imaging in adolescents undergoing LAGB, describe the most common abnormal preoperative imaging findings, and illustrate the typical appearance and variants on postoperative upper-gastrointestinal (UGI) examinations.

MATERIALS AND METHODS

A retrospective chart review was performed of all adolescents from 2008 to 2010 undergoing LAGB at a single tertiary-care pediatric hospital. The picture archiving and communication system was queried for all imaging obtained before and after surgery. Postoperative UGI studies were analyzed for common patterns.

RESULTS

Twenty-seven obese adolescents who underwent LAGB were identified. Twenty-five had preoperative imaging, most commonly a UGI study (81.5%). Eight UGI studies were abnormal but did not impact surgery. Preoperative chest and neck radiographs were also common. Intraoperative imaging was rare. Seventy-three postoperative UGI studies were performed on 22 children (range, 2-12 studies). A common postoperative imaging pattern was observed in 19/22 (86%) children. No complications were observed.

CONCLUSION

The most common pre- and postoperative imaging studies in adolescents undergoing LAGB are UGI studies. Pediatric radiologists should be familiar with the imaging of LAGB as this procedure becomes increasingly common.

[Non-alcoholic fatty liver disease and its association with clinical and biochemical variables in obese children and adolescents: effect of a one-year intervention on lifestyle]

OBJECTIVE

To study the frequency of non-alcoholic fatty liver disease (NAFLD), its relationship to clinical and biochemical variables, and the effect 12-month's lifestyle intervention in obese children and adolescents.

METHODS

Thirty-six obese patients aged 7 to 18 years, 42% female and 58% male, 72.2% prepubertal and 27.8% pubertal, were selected. Anthropometric measurements and glucose, insulin (baseline and after a glucose load), lipid profile, C-reactive protein, and aminotransferase tests were performed before and 12 months after dietary and physical activity intervention. Liver ultrasound was performed to determine the presence of NAFLD.

RESULTS

NAFLD was found in 66.7% (n=24), and was mild in 30.6%, moderate in 27.8%, and severe in 8.3%. Subjects with NAFLD had higher body mass index (BMI, p=0.007), waist (p=0.005), fat area (p=0.002), basal insulin (p=0.01), and HOMA-IR (p=0.008) values and lower QUICKI (p=0.02) values than those with no NAFLD. After intervention, physical activity increased (p=0.0001) and calorie intake remained unchanged. NAFLD disappeared in 9 patients (37.5%, p=0.02) and disease severity decreased in 3 patients (12.5%). In addition, BMI Z-score (p=0.005), fat area (p=0.0001), basal insulin (p<0.05), insulin resistance (p<0.005), lipid profile (p<0.03), and transaminases decreased. Weight loss was the main variable accounting for NAFLD improvement.

CONCLUSION

This group of obese children and adolescents showed a high frequency of NAFLD. The lifestyle intervention with weight reduction is effective for the treatment of NAFLD.