Pediatric Non-Alcoholic Fatty Liver Disease: Etiologies, Features, Treatment and Implications for the RD

Deborah Cohen, DCN, RDAssistant Professor

UNM Nutrition Program

Pediatric Non-Alcoholic Fatty Liver Disease:

Etiologies, Features, Treatment and Implications for the RD

Objectives1. Discuss the prevalence of pediatric non-alcoholic fatty

liver disease (NAFLD) in the United States.

2. Identify the major risk factors that contribute to the development of NAFLD.

3. Review the biochemical and anthropometric features of pediatric NAFLD.

4. Discuss the recommendations for preventing and treating pediatric NAFLD, based on the current research.

25,000 U.S. Deaths Linked to Sugary Drinks

| ABC News – Wed, Mar 20, 2013 12:29 AM EDT

Non-alcoholic fatty liver disease (NAFLD)Describes a spectrum of steatotic liver disease generally associated with obesity and metabolic syndrome

HTN, dyslipidemia, increased waist circumference, insulin resistance

PrevalenceMost common pediatric chronic liver disease in US and globally

2.6%-9.6%

Prevalence depends on population studiedStudies from Europe, Asia, America: Overweight and obese children 24%-77% (severe obesity: up to 90%)More common in boys vs. girls

Study of Child and Adolescent Liver Epidemiology (SCALE)• Retrospective autopsy study (n=742, ages 2-19, 1993-2003, San Diego

County)• Fatty liver (≥5% of hepatocytes containing macrovesicular fat) was

present in 13% of subjectsoPrevalence of fatty liver (adjusted for age, gender, race, and

ethnicity) estimated to be 9.6% oPrevalence differed significantly by race and ethnicity • Asian: 10.2%; Black: 1.5%; Hispanic: 11.8%; White: 8.6%• The highest rate of fatty liver seen in obese children (38%).

Schwimmer et al. Prevalence of fatty liver in children and adolescents. Pediatrics. 2006;118(4):1388-1393.

Risk Factors Associated with NAFLDConditions with established association

Conditions with emerging association

ObesityType 2 diabetes mellitusDyslipidemiaMetabolic syndrome

Polycystic ovary syndromeHypothyroidismObstructive sleep apneaHypopituitarismHypogonadismPancreato-duodenal resection

Chalasani et al. The Diagnosis and Management of Non-Alcoholic Fatty Liver Disease: Practice Guideline by the American Association for the Study of Liver Diseases, American College of Gastroenterology, and the American Gastroenterological Association. Hepatology. 2012;55(6): 2005-2023.

Progression of fatty liver diseaseNonalcoholic fatty liver (NAFL)

Progression of hepatic steatosis with no evidence of hepatocellular injury.

Nonalcoholic steatohepatitis (NASH)Presence of hepatic steatosis with hepatocellular injury (ballooning) with or without fibrosis.

NASH Cirrhosis

Pathogenesis

De novo lipogenesis (DNL)Role of Insulin Resistance

“Two Hit” TheoryCytokines & Oxidative Stress

There are 3 major sources for the increased TG deposition in the liver:

Rate of FFA uptake and synthesis > need for FFA for essential functions

Impaired VLDL export

Increased de novo lipogenesis (DNL)synthesis of FA from CHO in the liver

Role of Insulin Resistance The liver is the main site of insulin action, in addition to skeletal muscle and adipose tissue.

Fatty liver: ability of insulin to inhibit hepatic glucose production is impaired (hyperglycemia).

Insulin resistance hyperglycemia, hyperinsulinemia…both stimulate DNL by activation of the transcription factors carbohydrate regulatory element-binding protein (ChREBP) & sterol regulatory element-binding proteins (SREBP-1c).

Insulin resistance stimulates the liver to overproduce TG rich VLDL in the fasting state.

The metabolic consequences of insulin resistance include:

Persistent hyperglycemiaHyperinsulinemia

Elevated serum FFA’sHypertriglyceridemia

It is unclear if insulin resistance and hyperglycemia cause NAFLD or are the consequences of the disease.

NAFLD can be considered the hepatic manifestation of metabolic syndrome.

“Two Hit” Theory

The first “hit” involves the accumulation of fat in the hepatocytes.

Subsequent “hits” involve:chronic oxidative stress with the production of reactive oxygen species (ROS)secretion of pro-inflammatory cytokinesmitochondrial dysfunctionliver injury, hepatic apoptosis (liver cell death) and fibrosis

Pro-inflammatory cytokines (TNF-α) are produced directly by hepatocytes in response to an increased supply of FFA and/or by adipose tissue macrophages that increase during obesity.

Fibrosis is thought to arise as part of the normal healing response to inflammation and injury.

Cytokines and Oxidative StressAdiponectin:

Inversely associated with obesity, BMI, metabolic syndrome, visceral adiposity, NAFLD

IL-6: Implicated in insulin resistance, NASH

TNF-α: Elevated levels with insulin resistance, metabolic syndrome

CRP: May be a marker for hepatic steatosis --- but not of severity of NAFLD

Pearce S et al. Noninvasive biomarkers for the diagnosis of steatohepatitis and advanced fibrosis in NAFLD. Biomarker Research.2013;1:7.

Role of Genetics

Global patterns of racial and ethnic distributions.

United States: Prevalence in Hispanic Americans, Asians and Native

Americans higher than in Caucasians & African-Americans.

Schwimmer et al. Prevalence of fatty liver in children and adolescents. Pediatrics 2006;118(4):1388-1393.

Several gene polymorphisms are associated with NAFLD & genes that influence:

insulin signaling and the regulation of fat metabolismoxidative stressresponses to endotoxinsrelease of cytokinesseverity of fibrosis

Genetic factors may also predispose certain individuals to environmental influences that promote the development of NAFLD.

Alisi et al. Nonalcoholic fatty liver disease and metabolic syndrome in adolescents: Pathogenetic role of genetic background and intrauterine environment. Ann Med. 2012;44(1)29-40.

Polymorphisms (single nucleotide polymorphisms or SNPs) in genes encoding proteins involved in the synthesis, storage, and export of TG may play a role in NAFLD susceptibility.

PNPLA3 (patatin-like phospholipase domain-containing protein 3, Adiponutrin)

Function not entirely known but is reported to have lipase-like activity and to promote TG hydrolysis in the liver.

• SNP (methionine substituted for isoleucine at codon 148 in the gene PNPLA3 has been determined to regulate a variety of the mechanisms involved with the development of NAFLD

HFE gene (human hemochromatosis protein)Gene involved with insulin sensitivity, oxidative stress.

Several investigators have found a genetic association between PNPLA3 polymorphisms and elevated plasma liver

enzymes in Hispanic populations.

Romeo et al. Genetic variation in PNPLA3 confers susceptibility to nonalcoholic fatty liver disease. Nature Genetics. 2008.40(2):1461-1465.

Quan et al. PNPLA3 polymorphisms and liver aminotransferase levels in a Mexican American population. Clin Invest Med. 2012 August 4; 35(4): E237.

Romeo et al. The 148M allele of the PNPLA3 gene is associated with indices of liver damage early in life. J Hepatol. 2010;53:35-338.•N = 475 overweight/obese children & adolescents (Italy)

age 10 ± 3; genotyped; anthropometric, biochemical and US data obtained

• Carriers of two 148M alleles had a 52% increase in circulating ALT levels compared to carriers of two 148I alleles.

• Liver steatosis was more prevalent in carriers of two 148M alleles.

• Glucose tolerance and insulin sensitivity were similar across all three genotypes.

Carriers of the PNPLA3 148M allele: more likely to exhibit hepatic damage at an early age.

Genetics may play an important role particularly at early onset disease.

Use of genetic analysis and genotyping has the potential to become an important noninvasive tool for the screening and diagnosis of NAFLD.

Features

Histological Classification of steatosis

BiochemicalInsulin resistance, Hypertriglyceridemia, elevated ALT

Anthropometric FindingsOverweight, obesity, abdominal obesity

Clinical FeaturesAcanthosis nigricans

Diagnostic ImagingMRI, CT, ultrasound

Histological NAFL

presence of hepatic steatosis with no evidence of hepatocellular injury in the form of ballooning of the hepatocytes.

NASHhepatic steatosis and inflammation with hepatocyte injury (ballooning) with or without fibrosis.

Spectrum of disease in NAFLD

A: Nonalcoholic fatty liver (NAFL)

B: Nonalcoholic steatohepatitis (NASH)

C: Cirrhosis

Histological Features

Brunt EM et al. Nonalcoholic steatohepatitis: a proposal for grading and staging the histological lesions. Am J Gastroenterol. 1999;94(9):2467-2474. Kleiner DE et al. Nonalcoholic Steatohepatitis Clinical Research network. Design and validation of a histological scoring system for nonalcoholic fatty liver disease. Hepatology 2005;41(6):1313-1321.

Biochemical FeaturesElevated serum TG

> 150 mg/dL

Elevated ALTo No universal standards for childreno 30-45 U/L most commonly used cutoff for abnormal ALTo ALT may be normalo Current standards controversial—range may be too high

Insulin resistance

Homeostatic Model Assessment Insulin Resistance (HOMA-IR) fasting glucose (mg/dl) × fasting insulin (μU/ml)

405 >3

Abdominal obesityWC > 90th percentile

OverweightBMI >95th percentile

ObesityBMI >95th percentile

Anthropometric Features

International Diabetes Federation (IDF) Criteria for the Classification of Metabolic Syndrome in Children

Age

6 - 10 years 10 – 16 years > 16 years

Definition of adiposity

WC > 90th percentile

WC > 90th percentile WC > 90th percentile

Blood glucose No set value FBG >100 mg/dL FBG > 100 mg/dL

Dyslipidemia No set value TG > 150 mg/dLHDL < 40 mg/dL

TG > 150 mg/dLHDL < 40 mg/dL

Blood Pressure No set value Systolic >130 mm HgDiastolic >85 mm Hg

Systolic >130 mm HgDiastolic >85 mm Hg

Clinical FeaturesAcanthosis nigricansHepatomegaly on palpation

DiagnosisLiver biopsy

invasive, risks, expensive

Magnetic Resonance Imaging (MRI)

no exposure to ionizing radiationexpensive!

Computerized Tomography (CT)exposure to ionizing radiation

Ultrasoundaccessible, no ionizing radiation exposurelow sensitivity: mild-moderate steatosislimited beam penetration in obese individuals

Diagnostic Imaging

MRI of the Liver Ultrasound image of the Liver

CT image of the Liver

Dietary Characteristics overconsumption of fructose & soft drinks

lower consumption of fiber

overconsumption of meat/saturated fat/cholesterol

lower consumption of fish, omega-3 fatty acids, and lower consumption of some vitamins (vitamin E)

Zelber-Sagi et al. Nutrition and physical activity in NAFLD: An overview of the epidemiological evidence. World J Gastroenterol. 2011; 17(29): 3377–3389.

Nutritional FactorsRole of CHO

SucroseIncreases hepatic TG synthesis

FructoseIncreases DNL & insulin resistance in animal models

Fructose overfeeding increases fasting and postprandial plasma TG hepatic DNL, VLDL-TG secretion & decreased VLDL-TG clearance

Tappy L. Does fructose consumption contribute to non-alcoholic fatty liver disease? Clinics Res Gastroent Hepatol. 2012;36(6):554-560.

A possible explanation:Insulin resistance and hyperglycemia develops primarily in presence of sustained fructose exposures associated with changes in body composition.

Tappy L. Does fructose consumption contribute to non-alcoholic fatty liver disease? Clinics Res Gastroent Hepatol. 2012;36(6):554-560.

ObjectiveTo evaluate the effect of the addition of commonly consumed fructose/glucose containing sugars in the usual diet on liver fat and intramuscular adipose tissue (IMAT)

Materials & Methodso 64 adults, consumed low fat milk sweetened with either HFCS or

sucrose at different levels for 10 weekso CT: liver fato MRI: IMAT

Bravo et al. Consumption of sucrose and high fructose corn syrup does not increase liver fat or ectopic fat deposition in muscles. Appl Physiol Nutr Metab. Doi: 10.1139/apnm-2012-0322.

ResultsoNo increase in liver fat or IMAT

Authors ConclusionsoWhen fructose consumed as part of a typical diet as

sucrose or HFCS, liver fat storage is not promoted.

Limitations?

Sugar sweetened beveragesIncreased soda consumption in US children and adults~175 calories/day.

Duffey et al. Shifts in patterns and consumption of beverages between 1965 and 2002. Obesity. 2007;15:2739–2747.

Caramel coloring (contains advanced glycation end products) which can increase insulin resistance and inflammation.

Gaby AR. Adverse effects of dietary fructose. Altern Med Rev. 2005;10:294–306.

Zelber-Sagi S et al. Long term nutritional intake and the risk for non-alcoholic fatty liver disease (NAFLD): a population based study. J Hepatol. 2007;47:711–717.

o cross-sectional study of a sub-sample (n = 375) from the Israeli National Health and Nutrition Survey (1999-2001).

o semi-quantitative FFQ, abdominal US, biochemical, anthropometrics

o The NAFLD group consumed:o almost twice the amount of soft drinks (P = 0.03)o 27% more meat (P < 0.001)

o Subjects with NAFLD had a higher intake of soft drinkso Higher intake of soft drinks was associated with an increased risk of NAFLD,

independent of age, gender, BMI, and total calorie intake.

Polyunsaturated n-3 and n-6 fatty acidsAnimal models: reduction of steatosis

Studies in adults with NAFLD: improved lipid profiles, reduced inflammation

2 gm fish oil (6 mos, n=40 adults) reduced serum TG, liver enzymes, and TNF-α; regression of steatosis (US)

Spadaro L et al. Omega-3 polyunsaturated fatty acids: a pilot trial in non-alcoholic fatty liver disease. J Hepatol. 2006;44:S264

Bariatric surgeryLifestyle InterventionsPhysical activityWeight loss

Pharmacologic agentsMetforminVitamin E, omega 3 fats

Treatment

Physical activityExercise alone increases LBM, reduces adipose, improves insulin resistance.

Weight loss

As little as a 7-10% reduction in total body weight (regardless of diet composition) may reduce hepatic fat accumulation in obese adults and adolescents.

Promrat K et al. Randomized controlled trial testing the effects of weight loss on nonalcoholic steatohepatitis (NASH). Hepatology. 2010;51(1):121-129.

Reduction in intrahepatic fat has been reported to occur in obese adults with type 2 diabetes in as little as the two weeks of dietary restriction + exercise.

Tamura Y et al. Effects of diet ad exercise on muscle and liver intracellular lipid contents and insulin sensitivity in type 2 diabetic patients. J Endocrinol Metab. 2005;90(6):3191-3196.

Rapid weight loss >1.6 kg per week is not recommended due to the risk of liver damage.

Pharmacologic agentsMetformin

Metabolic effectsSafety profileFew studies in children with fatty liver diseaseNot recommended at this time for treatment of NAFLD

Vitamin E

Potent antioxidant

Children with NASH, NAFLD have lower Vitamin E intakes

TONIC Trial

TONIC TrialObjective

To determine whether children with NAFLD would improve from therapeutic intervention with vitamin E or metformin.

Design, Setting, and Patients o Randomized, double-blind, double-dummy, placebo-controlled

clinical trial conducted at 10 university clinical research centerso N=173 patients (age 8-17 years)o biopsy-confirmed NAFLDo September 2005 - March 2010.

Interventions Daily dosing of 800 IU of vitamin E (58 patients), 1000 mg of metformin (57 patients), or placebo (58 patients) for 96 weeks.

Main Outcome Measures  o Sustained reduction in ALT defined as 50% or less of the baseline

level or 40 U/L or less at visits every 12 weeks from 48 to 96 weeks of treatment.

o Improvements in histological features of NAFLD and resolution of NASH were secondary outcome measures.

ConclusionNeither vitamin E nor metformin was superior to placebo in attaining the primary outcome of sustained reduction in ALT level in patients with pediatric NAFLD.

Lavine JE et al. Effect of Vitamin E or Metformin for treatment of nonalcoholic fatty liver disease in children and adolescents: The TONIC randomized controlled trial. JAMA. 2011;305(16):1659-1668.

Bariatric surgeryLap bands not FDA approved for <18 years

American Academy of Pediatrics (2004) Criteria:• failed >6 months of organized attempts at weight management.

• attained or nearly attained physiologic or skeletal maturity. Girls age > 13, boys age > 15

• BMI > 40 (with serious obesity related conditions) or have a BMI of greater than 50 with less severe obesity-related problems.

• Other organizations, including the American Society for Metabolic and Bariatric Surgery (ASMBS) , have less stringent weight criteria for teens.

o Proposed as a potential treatment for NASH in adolescents

Inge TH et al. Bariatric surgery for severely overweight adolescents: concerns and recommendations. Pediatrics.2004;114(1):217-223.

Implications for the RDSummary of diet and lifestyle recommendations

No consensus as to what diet or lifestyle approach due to lack of scientific evidence

Omega 3 fatty acids, high MUFA, fruits, vegetables, low GI, high fiber, reduced intake of saturated fats, simple CHO and sweetened beverages are universally recommended.

Alisi A, Nobili V. Non-alcoholic fatty liver disease in children now: Lifestyle changes and pharmacologic treatments. Nutrition. 2012;28(7-8):722-726.

Nutrition Assessment

AnthropometricBMI

Waist circumference

Skinfolds (?)

Fasting Serum insulin (μIU/mL)Tanner Stage I 2.6-15.5 (prepubertal)Tanner Stage II 8.3-22.0Tanner Stage III 8.5-23.0

HOMA-IR (>3)fasting glu (mg/dl) × fasting insulin (μU/ml) 405

ALT

Lipid panelHDL, LDL,

triglycerides

FBG

Biochemical

ClinicalAcanthosis nigricans

PMHPCOS, type 2 diabetes, insulin resistance

DietFFQ

20-60 questionsSSB, fruits, vegetables

3, 5 day food records (if possible)

<12 years: caregiver

Assess intake of sugar sweetened beverages:sodas, sweetened waters, teas, flavored milk, fruit juices, fruit drinks, energy drinks, sports drinks.

The type of fat (saturated vs. PUFA)

Fiber intake

Characterization of pediatric outpatients diagnosed with NAFLD at UNMH (anthropometric, biochemical)

o Retrospective x 5 years, N=38 o PI: Cohen, Gonzales-Pacheco

Genetics, diet and pediatric NAFLDo ages 11-17, recruitment from Health Fit Children's Clinic o Dietary intervention (SSB reduction), measurement of steatosis (US), genetic analysis,

biochemical featureso Baseline, 4 monthso PI: Cohen, Gonzales-Pacheco, Orlando, Garver, Negrete, Kong

Research at UNM

Concluding StatementsPrevention of overweight and obesity are KEY