Pediatric Non-alcoholic Fatty Liver Disease

Deciphering the Role of Selenoprotein M

Selenocysteine (Sec), the 21st amino acid, is structurally similar to cysteine but with a sulfur to selenium replacement. This single change retains many of the chemical properties of cysteine but often with enhanced catalytic and redox activity. Incorporation of Sec into proteins is unique, requiring additional translation factors and multiple steps to insert Sec at stop (UGA) codons. These Sec-containing proteins (selenoproteins) are found in all three domains of life where they often are involved in cellular homeostasis (e.g., reducing reactive oxygen species). The essential role of selenoproteins in humans requires us to maintain appropriate levels of selenium, the precursor for Sec, in our diet. Too much selenium is also problematic due to its toxic effects. Deciphering the role of Sec in selenoproteins is challenging for many reasons, one of which is due to their complicated biosynthesis pathway. However, clever strategies are surfacing to overcome this and facilitate production of selenoproteins. Here, we focus on one of the 25 human selenoproteins, selenoprotein M (SELENOM), which has wide-spread expression throughout our tissues. Its thioredoxin motif suggests oxidoreductase function; however, its mechanism and functional role(s) are still being uncovered. Furthermore, the connection of both high and low expression levels of SELENOM to separate diseases emphasizes the medical application for studying the role of Sec in this protein. In this review, we aim to decipher the role of SELENOM through detailing and connecting current evidence. With multiple proposed functions in diverse tissues, continued research is still necessary to fully unveil the role of SELENOM.

Review: Evaluating existing policies to address overweight and obesity in the Anglophone Caribbean: A narrative review of Barbados, Grenada, St. Lucia, and Trinidad & Tobago

Overweight and obesity continues to be a burden to the health and well-being of Caribbean residents. The rise of childhood obesity and non-communicable diseases within the Caribbean is a major public health challenge for policymakers, educators and health professionals. These alarming rates of obesity also pose a threat to the sustainability of existing health systems particularly in small island developing states like the Caribbean. Therefore, it is crucial to evaluate existing policies and create policy solutions to address these problems and reduce the potential impact later on. This systematic review explored existing policies among countries within the Anglophone Caribbean to identify trends within the region. The literature search focused on the following themes: (i) national policies (ii) school nutrition policies and programs (iii) physical activity among youth, and (iv) food import bill and food security. An analysis was conducted on literature from national, regional and international institutions including but not limited to the World Health Organization, Ministries of Health and the Healthy Caribbean Coalition. Countries throughout the region has acknowledged the challenges with overweight and obesity in the region. Collectively decisions have been made to address food insecurity and promote healthy lifestyle behaviours through policy changes. There's still a need for Caribbean countries to work together to create effective policy solutions in collaboration with community service organizations and other stakeholders. As small island developing states grappling with the same issues, pooling resources to create effective regional policies can help to address this public health crisis.

Relative Enhancement in Gadoxetate Disodium-Enhanced Liver MRI as an Imaging Biomarker in the Diagnosis of Non-Alcoholic Fatty Liver Disease in Pediatric Obesity

Relative enhancement (RE) in gadoxetate disodium (Gd-EOB-DTPA)-enhanced MRI is a reliable, non-invasive method for the evaluation and differentiation between simple steatosis and non-alcoholic steatohepatitis in adults. This study evaluated the diagnostic accuracy of RE in Gd-EOB-DTPA-enhanced liver MRI and hepatic fat fraction (HFF) in unenhanced liver MRI and ultrasound (US) for non-alcoholic fatty liver disease (NAFLD) screening in pediatric obesity. Seventy-four liver US and MRIs from 68 pediatric patients (13.07 ± 2.95 years) with obesity (BMI > BMI-for-age + 2SD) were reviewed with regard to imaging biomarkers (liver size, volume, echogenicity, HFF, and RE in Gd-EOB-DTPA-enhanced MRIs, and spleen size), blood biomarkers, and BMI. The agreement between the steatosis grade, according to HFF in MRI and the echogenicity in US, was moderate. Alanine aminotransferase correlated better with the imaging biomarkers in MRI than with those in US. BMI correlated better with liver size and volume on MRI than in US. In patients with RE < 1, blood biomarkers correlated better with RE than those in the whole sample, with a significant association between gamma-glutamyltransferase and RE (p = 0.033). In conclusion, the relative enhancement and hepatic fat fraction can be considered as non-invasive tools for the screening and follow-up of NAFLD in pediatric obesity, superior to echogenicity on ultrasound.

Changes in the Prevalence of Overweight and Obesity among Peruvian Children under Five Years before and during the COVID-19 Pandemic: Findings from a Nationwide Population-Based Study

This study aimed to identify changes in the prevalence of childhood (children under five years of age) overweight and obesity in Peru as a whole and at the departmental level, before and during the coronavirus disease (COVID-19) pandemic. We performed a secondary data analysis of two Demographic and Family Health Surveys (2019 and 2021) in Peru. The outcome was childhood overweight and obesity, defined as a weight-for-height score greater than 2 standard deviations. Poisson log generalized linear regression models adjusted for sex and/or age in months of the child were fitted to obtain the prevalence ratios of the changes in childhood overweight and obesity from 2019 to 2021. The analysis included 41,533 (2019: 20,414; 2021: 21,119) participants. The prevalence of childhood overweight and obesity was 6.4% in 2019 and 7.8% in 2021. Female children, aged 2, 3 and 4 years, and mothers who self-identified as non-native, had secondary and higher education, belonged to the middle and richer wealth quintile and resided in an urban area, in a village, in a small city and in the coastal region showed the largest increases in the prevalence of childhood overweight and obesity in 2021 compared to 2019. The departments of Pasco, Apurímac, Junín, Cusco, Lambayeque and La Libertad presented the largest increases in the prevalence of these nutritional disorders. During the pandemic, an increase in the prevalence of childhood overweight and obesity was observed, with demographic and socioeconomic factors accounting for the largest increases in the prevalence rates. A restructuring of overweight and obesity control strategies is required to curb this steady increase.

Tryptophan Metabolism Is Associated with BMI and Adipose Tissue Mass and Linked to Metabolic Disease in Pediatric Obesity

The obesity epidemic has contributed to an escalating prevalence of metabolic diseases in children. Overnutrition leads to increased tryptophan uptake and availability. An association between the induction of the tryptophan catabolic pathway via indoleamine 2,3-dioxygenase (IDO) activity and obesity-related inflammation has been observed. This study aimed to investigate the impact of pediatric obesity on tryptophan metabolism and the potential relationship with metabolic disease. In this prospective cohort study, plasma kynurenine, tryptophan, and serotonin levels were measured by ELISA, and IDO activity was estimated by calculating the kynurenine/tryptophan ratio in a clinically characterized population with severe obesity (BMI ≥ 97th percentile) aged 9 to 19 (n = 125). IDO activity and its product kynurenine correlated with BMI z-score and body fat mass, whereas concentrations of serotonin, the alternative tryptophan metabolite, negatively correlated with these measures of adiposity. Kynurenine and tryptophan, but not serotonin levels, were associated with disturbed glucose metabolism. Tryptophan concentrations negatively correlated with adiponectin and were significantly higher in prediabetes and metabolically unhealthy obesity. In conclusion, BMI and body fat mass were associated with increased tryptophan catabolism via the kynurenine pathway and decreased serotonin production in children and adolescents with severe obesity. The resulting elevated kynurenine levels may contribute to metabolic disease in obesity.

Non-alcoholic fatty liver disease in obese children and adolescents: a role for nutrition?

Non-alcoholic fatty liver disease (NAFLD) has become the most common cause of chronic liver disease in children, paralleling the increasing prevalence of obesity worldwide. The pathogenesis of paediatric NAFLD is not fully understood, but it is known that obesity, nutrition, lifestyle variables, genetic and epigenetic factors may be causally involved in the development of this common metabolic liver disease. In particular, obesity and nutrition are among the strongest risk factors for paediatric NAFLD, which may exert their adverse hepatic effects already before birth. Excess energy intake induces hypertrophy and hyperplasia of adipose tissue with subsequent development of systemic insulin resistance, which is another important risk factor for NAFLD. Diet composition and in particular simple carbohydrate intake (especially high fructose intake) may promote the development of NAFLD, whereas non-digestible carbohydrates (dietary fiber), by affecting gut microbiota, may favour the integrity of gut wall and reduce inflammation, opposing this process. Saturated fat intake may also promote NAFLD development, whereas unsaturated fat intake has some beneficial effects. Protein intake does not seem to affect the development of NAFLD, but further investigation is needed. In conclusion, lifestyle modifications to induce weight loss, through diet and physical activity, remain the mainstay of treatment for paediatric NAFLD. The use of dietary supplements, such as omega-3 fatty acids and probiotics, needs further study before recommendation.

The Emerging Role of Sfrp5 and Wnt5a in the Pathogenesis of Obesity: Implications for a Healthy Diet and Lifestyle

In recent decades, the prevalence of obesity has risen dramatically worldwide among all age groups. Obesity is characterized by excess fat accumulation and chronic low-grade inflammation. The adipose tissue functions as a metabolically active endocrine organ secreting adipokines. A novel duo of adipokines, the anti-inflammatory secreted frizzled-related protein 5 (Sfrp5) and the proinflammatory wingless type mouse mammary tumor virus (MMTV) integration site family member 5A (Wnt5a), signal via the non-canonical Wnt pathway. Recent evidence suggests that Sfpr5 and Wnt5a play a key role in the pathogenesis of obesity and its metabolic complications. This review summarizes the current knowledge on the novel regulatory system of anti-inflammatory Sfrp5 and pro-inflammatory Wnt5a, and their relation to obesity and obesity-related complications. Future studies are required to investigate the potential role of Sfrp5 and Wnt5a as biomarkers for monitoring the response to lifestyle interventions and for predicting the development of cardiometabolic risk factors. These adipokines may also serve as novel therapeutic targets for obesity-related disorders.

Effects of Pterostilbene on Diabetes, Liver Steatosis and Serum Lipids

Pterostilbene, a phenolic compound derived from resveratrol, possesses greater bioavailability than its parent compound due to the presence of two methoxyl groups. In this review, the beneficial effects of pterostilbene on diabetes, liver steatosis and dyslipidemia are summarized. Pterostilbene is a useful bioactive compound in preventing type 1 diabetes, insulin resistance and type 2 diabetes in animal models. Concerning type 1 diabetes, the main mechanisms described to justify the positive effects of this phenolic compound are increased liver glycogen content and hepatic glucokinase and phosphofructokinase activities, the recovery of pancreatic islet architecture, cytoprotection and a decrease in serum and pancreatic pro-inflammatory cytokines. As for type 2 diabetes, increased liver glucokinase and glucose-6-phosphatase and decreased fructose-1,6-biphosphatase activities are reported. When insulin resistance is induced by diets, a greater activation of insulin signaling cascade has been reported, increased cardiotrophin-1 levels and liver glucokinase and glucose- 6-phosphatase activities, and a decreased fructose-1,6-biphosphatase activity. Data concerning pterostilbene and liver steatosis are scarce so far, but the reduction in oxidative stress induced by pterostilbene may be involved since oxidative stress is related to the progression of steatosis to steatohepatitis. Finally, pterostilbene effectively reduces total cholesterol, LDL-cholesterol and serum triglyceride levels, while increases HDL-cholesterol in animal models of dyslipidemia.

Gender-specific differences in clinical and metabolic variables associated with NAFLD in a Mexican pediatric population

INTRODUCTION AND OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in children and it is more prevalent in Hispanic males. The gender differences can be explained by body fat distribution, lifestyle, or sex hormone metabolism. We evaluated anthropometric and metabolic differences by gender in children with and without NAFLD.

METHODS

We included 194 participants (eutrophic, overweight, and individuals with obesity). The presence of NAFLD was determined using ultrasonography, and we evaluated the association between this disease with metabolic and anthropometric variables by gender.

RESULTS

The mean age was 10.64±2.54 years. The frequency of NAFLD in boys was 24.51% and in girls was 11.96% (OR=2.39; 95%CI=1.10-5.19; p=0.025). For girls, NAFLD was significantly associated with triglycerides (p=0.012), homeostatic model assessment of insulin resistance (HOMA-IR) (p=0.048), and the visceral adiposity index (VAI) (p=0.024). The variables related to NAFLD in a gender-specific manner were body mass index (BMI) (p=0.001), waist circumference (WC) (p<0.001), HDL cholesterol (p=0.021), alanine aminotransferase (ALT) (p<0.001), and aspartate aminotransferase (AST) (p=0.002).

CONCLUSIONS

In our study NAFLD is more frequent in boys, only ALT, and no other clinical or metabolic variables, were associated with NAFLD in these patients. HOMA-IR, VAI, triglyceride levels, and ALT were associated with NAFLD only in girls. The ALT cut-off points for the development of NAFLD in our study were 28.5U/L in females and 27.5U/L in males. Our findings showed that NAFLD should be intentionally screened in patients with obesity, particularly in boys.

Heightened Plasma Levels of Transforming Growth Factor Beta (TGF-β) and Increased Degree of Systemic Biochemical Perturbation Characterizes Hepatic Steatosis in Overweight Pediatric Patients: A Cross-Sectional Study

Nonalcoholic Fatty Liver Disease (NAFLD) is a common cause of chronic liver disease in childhood and strongly associated with obesity. Routine biochemical non-invasive tests remain with low accuracy for diagnosis of NAFLD. We performed a cross-sectional study to examine potential associations between anthropometric and biochemical parameters, specially TGF-β, a prognosis marker for hepatic steatosis (HS). Between May and October 2019, seventy-two overweight adolescents were enrolled, of which 36 had hepatic steatosis. Hepatic, lipidic and glycemic profiles, and levels of vitamin D, ferritin and TGF-β were analyzed. Hierarchical cluster and a discriminant model using canonical correlations were employed to depict the overall expression profile of biochemical markers and the biochemical degree of perturbation. Median values of alanine aminotransferase (ALT), gamma glutamyl transpeptidase (GGT), and TGF-β were higher in the adolescents with HS. Values of body mass index (BMI)/age and ALT, but not of TGF-β, were gradually increased proportionally to augmentation of steatosis severity. In a multivariate analysis, TGF-β plasma concentrations were associated with occurrence of hepatic steatosis independent of other covariates. Discriminant analysis confirmed that TGF-β concentrations can identify HS cases. Our data reveal that HS patients exhibit a distinct biosignature of biochemical parameters and imply TGF-β as an important biomarker to evaluate risk of steatosis development.

Comparative analysis of the expression profiles of genes related to the Gadd45α signaling pathway in four kinds of liver diseases

Gadd45α (growth arrest and DNA damage inducible alpha) is a member of a group of genes whose transcript levels are increased following stressful conditions that lead to growth arrest and treatment with agents that lead to DNA damage. Gadd45α is upregulated in liver cirrhosis (LC), hepatic cancer (HC), acute liver failure (AHF) and non-alcoholic fatty liver disease(NAFLD). Here, we investigated the essential differences in the Gadd45α signaling pathway in these diseases at the transcriptional level. The results showed that 44, 46, 71 and 27 genes significant changes in these diseases, and the H-cluster showed that the expression of the Gadd45α signaling-related genes was significantly different in the four liver diseases. DAVID functional analysis showed that the Gadd45α signaling pathway-related genes were mainly involved in cell adhesion and migration, cell proliferation, apoptosis, stress and inflammatory responses, etc. Ingenuity pathway analysis (IPA) software was used to predict the functions of the Gadd45α signaling-related genes, and the results indicated that there were significant changes in cell differentiation, DNA damage repair, autophagy, apoptosis and necrosis. Gadd45α signaling pathway is involved in four kinds of liver disease and regulates a variety of activities via P38 MAPK, NF-κB, mTOR/STAT3, P21, PCNA, PI3K/Akt and other signaling pathways. Modulation of Gadd45α may be exploited to prevent the progression of liver disease, and to identify specific treatments for different stages of liver disease. In summary, the Gadd45α signaling pathway is involved in four kinds of liver disease and regulates a variety of physiological activities through various signaling pathways.

Adelmidrol protects against non-alcoholic steatohepatitis in mice

Non-alcoholic steatohepatitis (NASH) is a more serious condition of non-alcoholic fatty liver disease (NAFLD), a widely spread type of chronic liver disease. Oxidative stress and inflammation induced by lipotoxicity are involved in hepatic injury of NASH. This work aimed to investigate the possible protective effect of adelmidrol (PPAR α and γ agonist) against NASH in mice.Thirty-six mice were divided into six equal groups: sham-operated, NASH, vehicle, adelmidrol 5 mg/kg, adelmidrol 10 mg/kg, and adelmidrol 20 mg /kg. Adelmidrol was injected intraperitoneally once daily for 7 weeks along with high-fat diet (HFD). Mice were euthanized, and livers were removed for light microscopic examination and detection of reduced glutathione (GSH) content while blood samples were collected for assessment of transaminases (ALT& AST), tumor necrosis factor (TNF-α), matrix metalloproteinase-1 (MMP-1), adiponectin, cholesterol, high-density lipoprotein (HDL), and triglyceride. NASH mice had increments in MMP-1, TNF-α, AST, ALT, triglyceride, and cholesterol levels while HDL, adiponectin levels, and GSH content were decreased with vesicular steatosis, lobular inflammation, hepatocyte ballooning, and degeneration. Administration of adelmidrol decreased MMP-1, TNF-α, AST, ALT, triglyceride, and cholesterol levels while increased HDL, adiponectin levels, and GSH content as well as ameliorated the histopathological changes. Adelmidrol protected mice from NASH; an effect could be attributed to its anti-inflammatory and antioxidant actions.

The epidemiological burden of obesity in childhood: a worldwide epidemic requiring urgent action

BACKGROUND

In recent decades, the prevalence of obesity in children has increased dramatically. This worldwide epidemic has important consequences, including psychiatric, psychological and psychosocial disorders in childhood and increased risk of developing non-communicable diseases (NCDs) later in life. Treatment of obesity is difficult and children with excess weight are likely to become adults with obesity. These trends have led member states of the World Health Organization (WHO) to endorse a target of no increase in obesity in childhood by 2025.

MAIN BODY

Estimates of overweight in children aged under 5 years are available jointly from the United Nations Children's Fund (UNICEF), WHO and the World Bank. The Institute for Health Metrics and Evaluation (IHME) has published country-level estimates of obesity in children aged 2-4 years. For children aged 5-19 years, obesity estimates are available from the NCD Risk Factor Collaboration. The global prevalence of overweight in children aged 5 years or under has increased modestly, but with heterogeneous trends in low and middle-income regions, while the prevalence of obesity in children aged 2-4 years has increased moderately. In 1975, obesity in children aged 5-19 years was relatively rare, but was much more common in 2016.

CONCLUSIONS

It is recognised that the key drivers of this epidemic form an obesogenic environment, which includes changing food systems and reduced physical activity. Although cost-effective interventions such as WHO 'best buys' have been identified, political will and implementation have so far been limited. There is therefore a need to implement effective programmes and policies in multiple sectors to address overnutrition, undernutrition, mobility and physical activity. To be successful, the obesity epidemic must be a political priority, with these issues addressed both locally and globally. Work by governments, civil society, private corporations and other key stakeholders must be coordinated.

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.

The Level of Vitamin D in Children and Adolescents with Nonalcoholic Fatty Liver Disease: A Meta-Analysis

Background

The relationship between vitamin D level and NAFLD has not been investigated in children and adolescents. We performed a meta-analysis of published observational studies to assess this association between vitamin D levels (measured as serum 25-hydroxy vitamin D [25(OH)D]) and NAFLD in this age group.

Methods

Relevant studies conducted before May 20, 2018, were identified from the following electronic databases: PubMed, the Cochrane Library, Embase, and the Chinese CNKI databases. The quality of the included studies was evaluated using the Newcastle Ottawa Scale, and associations between vitamin D levels and NAFLD were estimated using standardised mean differences (SMD) and 95% confidence interval (CI). Subgroup and sensitivity analysis were used to identify sources of heterogeneity, and publication bias was evaluated using funnel plots.

Results

Eight articles were included in this meta-analysis. A significant difference was observed between low 25(OH)D levels and NAFLD in children and adolescents (SMD = -0.59, 95%CI = -0.98, -0.20, P <  0.01). Subgroup analysis revealed no differences in the study type, geographic location, BMI, and age subgroups.

Conclusions

Low vitamin D levels were associated with NAFLD in children and adolescents.

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.

The gut microbiota in infants of obese mothers increases inflammation and susceptibility to NAFLD

Maternal obesity is associated with increased risk for offspring obesity and non-alcoholic fatty liver disease (NAFLD), but the causal drivers of this association are unclear. Early colonization of the infant gut by microbes plays a critical role in establishing immunity and metabolic function. Here, we compare germ-free mice colonized with stool microbes (MB) from 2-week-old infants born to obese (Inf-ObMB) or normal-weight (Inf-NWMB) mothers. Inf-ObMB-colonized mice demonstrate increased hepatic gene expression for endoplasmic reticulum stress and innate immunity together with histological signs of periportal inflammation, a histological pattern more commonly reported in pediatric cases of NAFLD. Inf-ObMB mice show increased intestinal permeability, reduced macrophage phagocytosis, and dampened cytokine production suggestive of impaired macrophage function. Furthermore, exposure to a Western-style diet in Inf-ObMB mice promotes excess weight gain and accelerates NAFLD. Overall, these results provide functional evidence supporting a causative role of maternal obesity-associated infant dysbiosis in childhood obesity and NAFLD.

Mitochondrial role in the neonatal predisposition to developing nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a global epidemic in obese children and adults, and the onset might have fetal origins. A growing body of evidence supports the role of developmental programming, whereby the maternal environment affects fetal and infant development, altering the risk profile for disease later in life. Human and nonhuman primate studies of maternal obesity demonstrate that risk factors for pediatric obesity and NAFLD begin in utero. The pathologic mechanisms for NAFLD are multifactorial but have centered on altered mitochondrial function/dysfunction that might precede insulin resistance. Compared with the adult liver, the fetal liver has fewer mitochondria, low activity of the fatty acid metabolic enzyme carnitine palmitoyl-CoA transferase-1, and little or no gluconeogenesis. Exposure to excess maternal fuels during fetal life uniquely alters hepatic fatty acid oxidation, tricarboxylic acid cycle activity, de novo lipogenesis, and mitochondrial health. These events promote increased oxidative stress and excess triglyceride storage, and, together with altered immune function and epigenetic changes, they prime the fetal liver for NAFLD and might drive the risk for nonalcoholic steatohepatitis in the next generation.

Free-breathing quantification of hepatic fat in healthy children and children with nonalcoholic fatty liver disease using a multi-echo 3-D stack-of-radial MRI technique

BACKGROUND

In adults, noninvasive chemical shift encoded Cartesian magnetic resonance imaging (MRI) and single-voxel magnetic resonance (MR) spectroscopy (SVS) accurately quantify hepatic steatosis but require breath-holding. In children, especially young and sick children, breath-holding is often limited or not feasible. Sedation can facilitate breath-holding but is highly undesirable. For these reasons, there is a need to develop free-breathing MRI technology that accurately quantifies steatosis in all children.

OBJECTIVE

This study aimed to compare non-sedated free-breathing multi-echo 3-D stack-of-radial (radial) MRI versus standard breath-holding MRI and SVS techniques in a group of children for fat quantification with respect to image quality, accuracy and repeatability.

MATERIALS AND METHODS

Healthy children (n=10, median age [±interquartile range]: 10.9 [±3.3] years) and overweight children with nonalcoholic fatty liver disease (NAFLD) (n=9, median age: 15.2 [±3.2] years) were imaged at 3 Tesla using free-breathing radial MRI, breath-holding Cartesian MRI and breath-holding SVS. Acquisitions were performed twice to assess repeatability (within-subject mean difference, MD_within). Images and hepatic proton-density fat fraction (PDFF) maps were scored for image quality. Free-breathing and breath-holding PDFF were compared using linear regression (correlation coefficient, r and concordance correlation coefficient, ρ_c) and Bland-Altman analysis (mean difference). P<0.05 was considered significant.

RESULTS

In patients with NAFLD, free-breathing radial MRI demonstrated significantly less motion artifacts compared to breath-holding Cartesian (P<0.05). Free-breathing radial PDFF demonstrated a linear relationship (P<0.001) versus breath-holding SVS PDFF and breath-holding Cartesian PDFF with r=0.996 and ρ_c=0.994, and r=0.997 and ρ_c=0.995, respectively. The mean difference in PDFF between free-breathing radial MRI, breath-holding Cartesian MRI and breath-holding SVS was <0.7%. Repeated free-breathing radial MRI had MD_within=0.25% for PDFF.

CONCLUSION

In this pediatric study, non-sedated free-breathing radial MRI provided accurate and repeatable hepatic PDFF measurements and improved image quality, compared to standard breath-holding MR techniques.

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.

Versatile Histochemical Approach to Detection of Hydrogen Peroxide in Cells and Tissues Based on Puromycin Staining

Hydrogen peroxide (H2O2) is a central reactive oxygen species (ROS) that contributes to diseases from obesity to cancer to neurodegeneration but is also emerging as an important signaling molecule. We now report a versatile histochemical approach for detection of H2O2 that can be employed across a broad range of cell and tissue specimens in both healthy and disease states. We have developed a first-generation H2O2-responsive analogue named Peroxymycin-1, which is based on the classic cell-staining molecule puromycin and enables covalent staining of biological samples and retains its signal after fixation. H2O2-mediated boronate cleavage uncages the puromycin aminonucleoside, which leaves a permanent and dose-dependent mark on treated biological specimens that can be detected with high sensitivity and precision through a standard immunofluorescence assay. Peroxymycin-1 is selective and sensitive enough to image both exogenous and endogenous changes in cellular H2O2 levels and can be exploited to profile resting H2O2 levels across a panel of cell lines to distinguish metastatic, invasive cancer cells from less invasive cancer and nontumorigenic counterparts, based on correlations with ROS status. Moreover, we establish that Peroxymycin-1 is an effective histochemical probe for in vivo H2O2 analysis, as shown through identification of aberrant elevations in H2O2 levels in liver tissues in a murine model of nonalcoholic fatty liver disease, thus demonstrating the potential of this approach for studying disease states and progression associated with H2O2. This work provides design principles that should enable development of a broader range of histochemical probes for biological use that operate via activity-based sensing.

The role of NAFLD in cardiometabolic disease: an update

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the world, yet the complex pathogenesis remains to be fully elucidated. The prevalence of NAFLD has risen precipitously in recent years and is now a leading indication for liver transplantation. New waitlist registrants with non-alcoholic steatohepatitis–induced cirrhosis increased by 170% from 2004 to 2013. In addition, patients with NAFLD are at increased risk of both cardiovascular disease and type II diabetes. In this update, recent studies contributing to the understanding of the place of NAFLD in cardiometabolic disease will be discussed.

The impact of childhood overweight and obesity on healthcare utilisation

Rising levels of childhood overweight and obesity represent a major global public health challenge. A number of studies have explored the association between childhood overweight and obesity and healthcare utilisation and costs. This paper adds to the literature by estimating the causal effect of child overweight and obesity status on use of general practitioner (GP) and hospital inpatient stays at two time points using instrumental variable (IV) methods The paper uses data from two waves of the Growing Up in Ireland survey of children when they are 9 and 13 years respectively and uses the biological mother's body mass index (BMI) as an instrument for the child's BMI. Our results demonstrate that child overweight and obesity status do not have a significant effect on healthcare utilisation for children when they are 9 years, but do have a large and significant effect at 13 years. Across all our models, the effects on both GP and hospital inpatient stays are found to be larger when endogeneity in childhood BMI status is addressed. Previous studies that did not address endogeneity concerns are likely to have significantly underestimated the impact of child overweight and obesity status on healthcare utilisation.

Serum bile acid level and fatty acid composition in Chinese children with non-alcoholic fatty liver disease

OBJECTIVE

To determine serum bile acid (BA) and fatty acid (FA) profiles in Chinese children with non-alcoholic fatty liver disease (NAFLD).

METHODS

A total 76 children aged 4-17 years were categorized into three groups according to the presence and absence of as well as the severity of NAFLD, that is, non-NAFLD (control), mild and moderate to severe NAFLD groups, respectively, based on their liver ultrasonography findings. Serum BA and FA profiles were quantified separately by mass spectrometry and gas chromatography. General linear models were performed to assess the differences among the groups.

RESULTS

After adjusted for potential confounders, children with NAFLD had higher levels of chenodeoxycholic acid (CDCA), unconjugated primary BAs (CDCA + cholic acid) but lower levels of deoxycholic acid (DCA), taurodeoxycholic acid (TDCA), glycodeoxycholic acid (GDCA), total DCA (DCA + TDCA + GDCA), glycolithocholic acid (GLCA) and total lithocholic acid (GLCA + taurolithocholic acid) than children without NAFLD. As for FAs, children with mild and moderate to severe NAFLD had higher levels of n-7 monounsaturated FA.

CONCLUSIONS

Circulating BA and FA profiles may change in children with NAFLD. Further studies are needed to determine their associations and to understand the underlying mechanism of action.

Current Concepts in Pediatric Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of disease. Its increasing prevalence is a direct result of historically high rates of obesity. Hepatocyte lipid accumulation is the first step in a cascade of metabolic and inflammatory events thought to precipitate NAFLD. Histologic findings provide insight into these events. Lifestyle modification remains the primary therapy in children. Current recommendations include vitamin E treatment in those with biopsy-proven NASH. Trials of novel drugs are ongoing in adults. As efficacy/safety are established, these therapies may be tenable for use in children. At the current time, biopsy-driven histology endpoints are necessary to establish whether future therapies can improve pediatric or adult-type NASH in children.

In vivo bioluminescence imaging reveals copper deficiency in a murine model of nonalcoholic fatty liver disease

Copper is a required metal nutrient for life, but global or local alterations in its homeostasis are linked to diseases spanning genetic and metabolic disorders to cancer and neurodegeneration. Technologies that enable longitudinal in vivo monitoring of dynamic copper pools can help meet the need to study the complex interplay between copper status, health, and disease in the same living organism over time. Here, we present the synthesis, characterization, and in vivo imaging applications of Copper-Caged Luciferin-1 (CCL-1), a bioluminescent reporter for tissue-specific copper visualization in living animals. CCL-1 uses a selective copper(I)-dependent oxidative cleavage reaction to release d-luciferin for subsequent bioluminescent reaction with firefly luciferase. The probe can detect physiological changes in labile Cu+ levels in live cells and mice under situations of copper deficiency or overload. Application of CCL-1 to mice with liver-specific luciferase expression in a diet-induced model of nonalcoholic fatty liver disease reveals onset of hepatic copper deficiency and altered expression levels of central copper trafficking proteins that accompany symptoms of glucose intolerance and weight gain. The data connect copper dysregulation to metabolic liver disease and provide a starting point for expanding the toolbox of reactivity-based chemical reporters for cell- and tissue-specific in vivo imaging.

Pathogenesis of Nonalcoholic Steatohepatitis: Interactions between Liver Parenchymal and Nonparenchymal Cells

Nonalcoholic fatty liver disease (NAFLD) is the most common type of chronic liver disease in the Western countries, affecting up to 25% of the general population and becoming a major health concern in both adults and children. NAFLD encompasses the entire spectrum of fatty liver disease in individuals without significant alcohol consumption, ranging from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH) and cirrhosis. NASH is a manifestation of the metabolic syndrome and hepatic disorders with the presence of steatosis, hepatocyte injury (ballooning), inflammation, and, in some patients, progressive fibrosis leading to cirrhosis. The pathogenesis of NASH is a complex process and implicates cell interactions between liver parenchymal and nonparenchymal cells as well as crosstalk between various immune cell populations in liver. Lipotoxicity appears to be the central driver of hepatic cellular injury via oxidative stress and endoplasmic reticulum (ER) stress. This review focuses on the contributions of hepatocytes and nonparenchymal cells to NASH, assessing their potential applications to the development of novel therapeutic agents. Currently, there are limited pharmacological treatments for NASH; therefore, an increased understanding of NASH pathogenesis is pertinent to improve disease interventions in the future.