Nonalcoholic fatty liver disease and bariatric surgery in adolescents

Deciphering the role of aberrant DNA methylation in NAFLD and NASH

The global incidence of nonalcoholic fatty liver disease (NAFLD) is mounting incessantly, and it is emerging as the most frequent cause of chronic and end stage liver disorders. It is the starting point for a range of conditions from simple steatosis to more progressive nonalcoholic steatohepatitis (NASH) and associated hepatocellular carcinoma (HCC). Dysregulation of insulin secretion and dyslipidemia due to obesity and other lifestyle variables are the primary contributors to establishment of NAFLD. Onset and progression of NAFLD is orchestrated by an interplay of metabolic environment with genetic and epigenetic factors. An incompletely understood mechanism of NAFLD progression has greatly hampered the progress in identification of novel prognostic and therapeutic strategies. Emerging evidence suggests altered DNA methylation pattern as a key determinant of NAFLD pathogenesis. Environmental and lifestyle factors can manipulate DNA methylation patterns in a reversible manner, which manifests as changes in gene expression. In this review we attempt to highlight the importance of DNA methylation in establishment and progression of NAFLD. Development of novel diagnostic, prognostic and therapeutic strategies centered around DNA methylation signatures and modifiers has also been explored.

The triglycerides and glucose index is strongly associated with hepatic steatosis in children with overweight or obesity

Given the worldwide increase prevalence of overweight, obesity, and nonalcoholic fatty liver disease (NAFLD), the objective of this study was to evaluate whether the triglycerides and glucose (TyG) index is associated with hepatic steatosis in children with overweight or obesity. Apparently healthy children aged 5‑17 years were included and allocated into the groups with and without hepatic steatosis. The TyG index was calculated as Ln [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)]/2. Hepatic steatosis was diagnosed by ultrasonography. A total of 177 children, 66 (37.3%) girls and 111 (62.7%) boys, were included in the study. According to the hepatic ultrasonography, they were allocated into the groups with (n = 100) and without (n = 77) hepatic steatosis. The adjusted analysis by gender, body mass index, and waist circumference revealed that HDL-C (OR 0.96; 95% CI: 0.93-0.99), triglycerides (OR 1.005; 95% CI: 1.001-1.009), AST (OR 1.03; 95% CI: 1.008-1.07), ALT (OR 1.03; 95% CI: 1.01-1.05), and TyG index (OR 4.07; 95% CI: 1.26-13.15) remained associated with hepatic steatosis.Conclusion: Compared to other biochemical markers, the TyG index is highly associated with the presence of fatty liver in children with overweight and obesity. What is known: • The triglycerides and glucose (TyG) index is effective in predicting high risk for incident nonalcoholic fatty liver disease (NAFLD) in adults. What is new: • Compared to other biochemical markers, the TyG index is highly associated with the presence of fatty liver in children with overweight or obesity. • The triglycerides and glucose index may be a useful tool to detect children at high risk of fatty liver.

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.

Bariatric Surgery in Children: Indications, Types, and Outcomes

PURPOSE OF REVIEW

The purpose of this review is to discuss the current state of surgical intervention for obesity in children and adolescents. Specifically, this review will discuss the different types of metabolic and bariatric surgery (MBS) procedures, guidelines for patient selection, and recent findings regarding surgical outcomes and complications.

RECENT FINDINGS

MBS is safe in adolescents and has also demonstrated sustainable long term weight loss and improvement in obesity-associated comorbidities. A recent prospective multi-institutional trial demonstrated BMI reductions of 3.8 kg/m² (8%) to 15.1 kg/m² (28%) after 3 years among adolescents undergoing the three most common MBS procedures. Moreover, MBS is associated with remission of type 2 diabetes, prediabetes, hypertension, dyslipidemia, and abnormal kidney function in 65-95% of patients in the study. Childhood and adolescent obesity is a continuing problem that has not been adequately addressed by the medical community. MBS is currently the most successful strategy for significant and sustained weight loss and improvement of associated comorbidities. This review focuses on the different types of MBS, the selection and preparation of patients for surgery, and the expected outcomes and common complications.

BMI Trajectories from Birth to Young Adulthood

OBJECTIVE

This study aimed to compare BMI trajectories from childhood to early adulthood in those with overweight and/or obesity versus severe obesity.

METHODS

Longitudinal BMI values (2,542 measurements) were calculated from measured heights and weights for 103 children, adolescents, or young adults with overweight, obesity, or severe obesity. Segmented regression with splines was used to model BMI trajectories.

RESULTS

Sixty-nine participants were classified as ever having severe obesity versus 34 who never had severe obesity. Trajectories and slopes did not differ by sex or race/ethnicity. Compared with those who never had severe obesity, BMI was higher in the group with severe obesity at all ages, and BMI slope was higher for those with severe obesity at age 14 (P = 0.002), with peak slope occurring later (18 years vs. 16 years) and higher (4.5 ± 0.5 kg/m² /y vs. 2.9 ± 0.5 kg/m² /y; P < 0.02). In the group without severe obesity, BMI fell below zero by the mid-20s (-0.3 ± 0.6 kg/m² /y); in those with severe obesity, BMI slope never reached zero (0.9 ± 0.5 kg/m² /y).

CONCLUSIONS

Youth with severe obesity, compared with their peers without, started with higher BMIs, had more rapid rates of BMI increase beginning at age 14, as well as a higher peak and longer period of increase, and never achieved weight stabilization.

Effects of activated carbon N-acetylcysteine sustained-release microcapsule on dipeptidyl peptidase IV expression in young rats with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) in children has become the most common liver disease influencing adolescent health and one of the most influencing chronic liver diseases among children in Chinese wealthy families, particularly in coastal regions. However, the medicine available for the treatment of NAFLD is deficient. In order to solve this problem, our team studied the activated carbon N-acetylcysteine (NAC) sustained-release microcapsule, which improves the oxidation resistance, bioavailability and drug stability of acetylcysteine and reduces toxic and side effects. In addition, it accords with the characteristics of medication in infants and children. The present study mainly discusses whether the activated carbon NAC sustained-release microcapsule has effects on dipeptidyl peptidase IV (DPPIV) activity and protein in young rats with NAFLD, and whether it has the effect of an DPPIV inhibitor, hoping to provide new thoughts and methods with respect of basic studies on young rats with NAFLD/non-alcoholic steatohepatitis.

What Is the Evidence for Paediatric/Adolescent Bariatric Surgery?

PURPOSE OF REVIEW

In spite of the increasing prevalence of severe and complex obesity in children, surgery as a potential management option is still not widely accepted. The purpose of this review is to examine the evidence for surgical options in the severely obese paediatric population. Increasing evidence supports early rather than later use of bariatric surgery in the treatment of extreme obesity.

RECENT FINDINGS

Prior to 2007, the feasibility and safety of surgery have been reported by predominantly small, sporadic single-centre retrospective case series. Increasing long-term data is now emerging due to the formation of multi-centre prospective national consortiums with two large, prospective long-term outcome studies published within the last year aiding our understanding of the efficacy and safety of bariatric surgery within the adolescent population. It is increasingly clear that adolescent bariatric surgery outcomes are comparable to adults, with similar sustainable weight loss, resolution of co-morbidities and complication rates. However, these studies are solely from dedicated specialist adolescent centres and results may not be reproducible if not performed in regulated environments with specialist multi-disciplinary teams.

Nonalcoholic fatty liver disease in long-term survivors of childhood-onset craniopharyngioma

PURPOSE

Hypothalamic obesity in childhood-onset (CO-) craniopharyngioma patients may predispose to nonalcoholic fatty liver disease (NAFLD). This study reviewed the characteristics of NAFLD associated with CO-craniopharyngioma.

METHODS

This study retrospectively reviewed 75 patients who underwent surgery for craniopharyngioma while younger than 15 years of age between 2000 and 2016.

RESULTS

Elevated aspartate aminotransferase (AST) or alanine aminotransferase (ALT) above 40 IU/L was observed in 51 of the 75 (68%) CO-craniopharyngioma patients. Imaging studies were performed in 32 patients with elevated liver enzymes. The estimated prevalence of NAFLD in CO-craniopharyngioma was 47%. NAFLD was detected in 22 patients (male 59%, 4.3±4.0 years after first surgery). The mean age at the time of the initial operation was 9.1±2.9 years. Six patients (27.3%) were diagnosed within 1 year. Among the 19 patients with initial height and weight data, the body mass index (BMI) z-score (BMI_Z) at the time of diagnosis with NAFLD was 1.37±1.01 (range, -0.75 to 3.18), with 4 patients (18.2%) being overweight and 9 (40.9%) being obese. BMI_Z increased above BMI_Z at the time of the operation in 13 patients (68.4%). The increment in BMI_Z was 1.13 (range, 0.10-2.84). Seventeen patients did not receive growth hormone. An insulin-like growth factor-I level <3rd percentile was observed in 19 patients.

CONCLUSIONS

NAFLD is common in survivors of CO-craniopharyngioma and may develop earlier. If the ALT or AST is above 40 IU/L, a diagnostic work-up should be started.

Update on Adolescent Bariatric Surgery

Childhood obesity remains a significant public health issue. Approximately 8% of adolescent girls and 7% of adolescent boys have severe (≥class 2) obesity. Adolescent severe obesity is associated with numerous comorbidities, and persists into adulthood. Bariatric surgery is the most effective treatment available, resulting in major weight loss and resolution of important comorbid conditions. Clinical practice guidelines for pediatric obesity treatment recommend consideration of surgery after failure of behavioral approaches. Careful screening and postoperative management of patients by a multidisciplinary team is required. Long-term studies are needed to assess the impact of adolescent bariatric surgery.

A Guide to Non-Alcoholic Fatty Liver Disease in Childhood and Adolescence

Non-Alcoholic Fatty Liver Disease (NAFLD) is now the most prevalent form of chronic liver disease, affecting 10%–20% of the general paediatric population. Within the next 10 years it is expected to become the leading cause of liver pathology, liver failure and indication for liver transplantation in childhood and adolescence in the Western world. While our understanding of the pathophysiological mechanisms underlying this disease remains limited, it is thought to be the hepatic manifestation of more widespread metabolic dysfunction and is strongly associated with a number of metabolic risk factors, including insulin resistance, dyslipidaemia, cardiovascular disease and, most significantly, obesity. Despite this, ”paediatric” NAFLD remains under-studied, under-recognised and, potentially, undermanaged. This article will explore and evaluate our current understanding of NAFLD in childhood and adolescence and how it differs from adult NAFLD, in terms of its epidemiology, pathophysiology, natural history, diagnosis and clinical management. Given the current absence of definitive radiological and histopathological diagnostic tests, maintenance of a high clinical suspicion by all members of the multidisciplinary team in primary and specialist care settings remains the most potent of diagnostic tools, enabling early diagnosis and appropriate therapeutic intervention.

Managing adolescent obesity and the role of bariatric surgery

PURPOSE OF REVIEW

This update explores the current management options for adolescent obesity with a specific focus on bariatric surgery.

RECENT FINDINGS

Research has highlighted the serious health complications associated with adolescent obesity and thus emphasized the need for effective interventions. With the increasing severity of obesity seen in younger populations, coupled with the modest effects of most behavioral and even pharmacologic interventions, there has been increased interest in, and attention on, bariatric surgery in younger populations. Recent adult-focused guidelines regarding the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient outline the importance of careful patient selection, in addition to close monitoring, with a particular focus on preventing nutritional deficiencies. Several recent publications have focused on issues specific to bariatric surgery in the adolescent patient including the relationship between a patient's physical and emotional maturity and timing of surgery.

SUMMARY

Adolescent obesity is prevalent with increasing severity and long-term health implications. To date nonsurgical interventions have had modest effects. Bariatric surgery is becoming more common and has been shown to be well tolerated and effective in adolescents, but requires careful preoperative screening and postoperative monitoring.

Review article: the management of paediatric nonalcoholic fatty liver disease

BACKGROUND

Paediatric nonalcoholic fatty liver disease (NAFLD) is a major public health concern given the recent increase in its prevalence and link to obesity and other metabolic comorbidities. Current treatment strategies involve lifestyle changes. Other surgical and pharmacologic interventions have been proposed; however, limited randomised controlled trials (RCTs) in the paediatric population restrict their use.

AIM

To review the current management of paediatric NAFLD, including lifestyle and pharmacologic interventions, and to formulate recommendations for study design for future studies.

METHODS

A MEDLINE, Pubmed and Cochrane Review database search used a combination of keywords, including NAFLD, nonalcoholic steatohepatitis (NASH), paediatric, treatments, lifestyle changes, bariatric surgery, orlistat, metformin, thiazolidinediones, vitamin E, cysteamine bitartrate, ursodeoxycholic acid (UDCA), probiotics, omega-3 fatty acids, pentoxyfylline, farnesoid X receptor agonist and toll-like receptor modifiers. The articles were selected based on their relevance to the review.

RESULTS

Lifestyle interventions involving diet and exercise remain first-line treatment for paediatric NAFLD. Bariatric surgery, orlistat, insulin sensitisers and UDCA have been evaluated but are not recommended as first or second-line therapy. Medications such as cysteamine bitartrate, probiotics, polyunsaturated fats and pentoxyfilline share beneficial effects in trials, however, there is a paucity of adequately powered RCTs in which liver histology is evaluated. Vitamin E has been shown to be effective and safe in improving NASH histology in children.

CONCLUSIONS

Lifestyle intervention should be first-line treatment for paediatric NAFLD. Vitamin E should be considered for those with biopsy-proven NASH or borderline NASH failing first-line therapy. Other therapeutics show promising results but require larger RCTs with convincing endpoints. Improved screening techniques, objective validated inclusion criteria and outcome measures as well as rigour in study design are necessary for propelling therapeutic discovery.