Lean Nonalcoholic Fatty Liver disease 목요세미나 Lean Nonalcoholic Fatty Liver disease 2018. 05. 31. R3 김광우 / Pf. 김원

Background Ref : https://www.google.co.kr/search?q=lean+nafld&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjD0IiIkpzbAhVDjJQKHT4xBSsQ_AUICigB&biw=1600&bih=745#imgrc=acppW_jm5qof3M:

Background Lean Nonalcoholic Fatty Liver Disease (NAFLD) Prevalence : Patients with a body mass index (BMI) <25 kg/m2 Prevalence - NAFLD : 25%, world wide - Lean NAFLD : varies from 7% in the United States to 19% in Asia Ref. : Lisa B. VanWagner and Matthew J. Armstrong, Lean NAFLD: A not so benign condition? Hepatol Commun. 2018 Jan; 2(1): 5–8.

Histological Severity and Clinical Outcomes of Nonalcoholic Fatty Liver Disease in Nonobese Patients Jonathan Chung-Fai Leung, et al. HEPATOLOGY 2017;65:54-64 Liver and Cardiovascular Damage in Patients With Lean Nonalcoholic Fatty Liver Disease, and Association With Visceral Obesity Anna Ludovica Fracanzani, et al. Clin Gastroenterol Hepatol. 2017 Oct;15(10):1604-1611.e1.

Histological Severity and Clinical Outcomes of Nonalcoholic Fatty Liver Disease in Nonobese Patients Jonathan Chung-Fai Leung, et al. HEPATOLOGY 2017;65:54-64 Liver and Cardiovascular Damage in Patients With Lean Nonalcoholic Fatty Liver Disease, and Association With Visceral Obesity Anna Ludovica Fracanzani, et al. Clin Gastroenterol Hepatol. 2017 Oct;15(10):1604-1611.e1.

Introduction NAFLD(Non-alcoholic fatty liver disease) Risk factors One of the most common chronic liver disease Progress to Non-alcoholic steatohepatitis (NASH), Cirrhosis, HCC Increased risk of cardiovascular event, malignancies, mortality Risk factors Obesity Metabolic syndromes (MetS) Cardiovascular risk factors

Introduction Severity, fibrosis, related factors, prognosis of More common in obese, but there is significant proportion of patients having relatively normal BMI  “Lean” or “Non-obese NAFLD” Not well understood Mixed results Severity, fibrosis, related factors, prognosis of Obese VS Nonobese NAFLD

Patients and Methods Patients Prospective cohort study Liver biopsy, non invasive test Indication for liver biopsy Unexplained elevation of liver enzymes Evaluation of NAFLD severity Participation in clinical trials Aged 18 or above, histology-proven NAFLD Excluded HBsAg (+), HCV Ab (+) with HCV RNA (+) Excessive alcohol consumption Secondary fatty liver Malignancy before baseline

Patients and Methods Clinical assessment History taking, blood test, transient elastography (TE) done 1 day before liver biopsy History taking : standardized questionnaire BMI: nonobese – less than 25 kg/m2 Waist circumference (WC) Liver biochemistry, glucose, insulin, lipids MetS: 3 or more of the followings Central obesity: men ≥ WC 90cm, women ≥ WC 80cm Triglyceride > 1.7 mmol/L HDL : men ≤ 1.03 mmol/L, women ≤ 1.29 mmol/L BP ≥ 130/85 mmHg Fasting plasma glucose ≥ 5.6 mmol/L Receiving treatment

Patients and Methods Assessment of disease severity Liver biopsy: 2 specimens, ≥ 15mm in length Score: NASH Clinical Research Network System NASH definition : Presence of steatosis, Lobular inflammation, Hepatocyte ballooning Fibrosis staging : F0–4, (F3–4 : advanced) Serum cytokeratin-18(CK-18) : Marker of hepatocyte apoptosis and NASH TE with Fibroscan : Liver stiffness measurement (LSM)

Patients and Methods Long-term Outcomes Primary analysis Prospectively followed yearly after baseline liver biopsy Crosscheck : Local EMR system Primary analysis Cardiovascular events Liver-related events Malignancies Mortality

Patients and Methods Statistical Analysis SPSS statistics software Continuous variables & Ordinal variables : Expression: mean ± SD, median (IQR) Comparison: unpaired t-test, Mann-Whitney U test Categorical variables: χ 2 test Independent variables NAFLD Activity Score (NAS): Ordinal logistic regression model Advanced liver fibrosis : Binary logistic regression model Clinical outcomes: Kaplan-Meier curves Compare with obese vs. non-obese : Log-rank test Total sample size 284  80% power to detect the difference at 5% significance level

Results

Results : Clinical characteristics of nonobese and obese patients

Results : NAFLD Activity in nonobese and obese patients

Results : Factors associated with disease activity in nonobese patients

Results : Fibrosis in nonobese and obese patients Less-severe fibrosis Lower liver stiffness by TE Similar in advanced fibrosis

Results : Factors associated with advanced fibrosis in nonobese patients

Results : Disease progression in nonobese and obese patients

Results : prognosis of nonobese and obese patients

Results : prognosis of nonobese and obese patients Clinical events occurred in 11.9% of obese patients and 8.3% of nonobese patients (P = 0.190)

Discussion Nonobese NAFLD patients Similar prevalence of NASH Lower NAS : lower degree of steatosis, hepatocyte ballooning Less likely to have liver fibrosis Similar proportions of patients with advanced fibrosis High TG  high NAS Creatinine (Cr.) : The only independent predictor of advanced fibrosis

Discussion Non-obese NAFLD histology : conflicting More lobular inflammation & higher mortality? Factors other than adiposity High TG associated with high NAS Only with steatosis, hepatocyte ballooning No effect to lobular inflammation High Cr. Level associated with advanced fibrosis Associated with chronic kidney disease In DM, early in nephropathy associated NAFLD, advanced fibrosis Genetic factors : PNPLA3, TM6SF2 PNPLA3: hepatic steatosis  disease severity, progression TM6SF2: disease progression In this study: No relationship (small number of nonobese patients with advanced disease)

Discussion Obese: more clinical events occur Cardiovascular, death  worse prognosis, high mortality Obesity itself related with cardiovascular event  Treatment : Weight loss Nonobese: better prognosis, lower mortality Longer study show higher mortality in nonobese  Long term prognosis study needed

Discussion Strength Limitation Prospective design Systematic follow-up Inclusion of histological, outcome data Biopsy largely verified noninvasive assessments Limitation Patients with NASH or advanced fibrosis relatively small Liver biopsy: only represents 1/50,000th of the entire liver  sampling bias Follow-up duration relatively short

Conclusions Nonobese patients with NAFLD tend to have less-severe disease and may have a better prognosis than obese patients. Hypertriglyceridemia, higher creatinine associated with advanced liver disease in nonobese patients. Further research on the relationships between these risk factors and advanced liver disease is needed.

Histological Severity and Clinical Outcomes of Nonalcoholic Fatty Liver Disease in Nonobese Patients Jonathan Chung-Fai Leung, et al. HEPATOLOGY 2017;65:54-64 Liver and Cardiovascular Damage in Patients With Lean Nonalcoholic Fatty Liver Disease, and Association With Visceral Obesity Anna Ludovica Fracanzani, et al. Clin Gastroenterol Hepatol. 2017 Oct;15(10):1604-1611.e1.

Introduction NAFLD(Non-alcoholic fatty liver disease) The most common liver disease in western countries, affecting 20% to 34% of the general population “Lean” NAFLD : NAFLD with a normal BMI (Body mass index) Major challenge in Diagnosis of Lean NAFLD Causes unclear Scanty, conflicting data on the severity of liver, cardiovascular damage : different methods used

Introduction Genetic factors Partly explain severe liver damage (NASH, advanced fibrosis), atherosclerotic disease I148M variant of the patatin-like phospholipase domain-containing-3 (PNPLA3) rs58542926 C>T genetic variant of the transmembrane 6 superfamily member 2 (TM6SF2) Asian population : higher prevalence of PNPLA3 mutations in lean NAFLD

Introduction Primary objective Secondary outcome Differences between lean and overweight/obese NAFLD Factors : severe liver disease, cardiovascular disease Secondary outcome Evaluated the role of visceral obesity : WC  On hepatic, vascular, metabolic alteration

Biopsy-proven NAFLD, Caucasian Methods Study Design and Participants 669 retrospective cohort Biopsy-proven NAFLD, Caucasian 324 Milan, 323 Palermo, 22 Catania Exclusion criteria: Viral B and C hepatitis, Wilson disease, a1-antitrypsin deficiency, Autoimmune hepatitis, Genetic hemochromatosis, Using drugs potentially causing steatosis, average Daily alcohol consumption (in grams of pure ethanol) higher than 20 g in women and 30 g in men (confirmed by at least 1 family member). 143 Lean 523 Overweight/Obese Smoking : current, former, never-smoker

Methods Data acquisition Diabetes mellitus (DM) Insulin resistance MetS Lean/Overweight/Obese : <25 kg/m2 / 25-29.9 kg/m2 / ≥ 30 kg/m2 WC (cm, men/women) : group A (<94 / <80), group B (94-102 / 80-88), group C (>102 / >88) Carotid atherosclerosis assessment : Mean carotid artery intima-media thickness (cIMT) Liver histology : grade steatosis, lobular inflammation, hepatocellular ballooning / stage fibrosis 0-4 / NAS 0-8 Insulin, adiponectin, and adipose tissue insulin resistance Genotyping : rs738409 C>G (I148M PNPLA3), rs58542926 C>T (E167K TM6SF2), singlenucleotide polymorphisms

Methods Data acquisition : Statistical analysis χ 2 test : categoric variables, compared in men and women Mann-Whitney or Kruskal-Wallis test : quantitative variables, compared in men and women) Multiple linear or logistic regression analyses : significant at univariate analyses (p <0.05) but including only one of the variables with a similar role Hosmer-Lemeshow test: Goodness-of-fit model Receiver operating characteristic (ROC) curve analysis : evaluated the diagnostic performance of PNPLA3 in lean NAFLD

Results : Characteristics of Lean and Overweight/Obese Nonalcoholic Fatty Liver Disease

Results : Factors Related to More Severe Liver and Cardiovascular Disease Multivariable Analysis Table 2. Variables Associated With NASH (Present in 240 Patients, 25 Among Lean and 215 Among Overweight/Obese) at Multivariate Analysis in Lean or Overweight/Obese NAFLD Patients

Results : Factors Related to More Severe Liver and Cardiovascular Disease Multivariable Analysis Table 3. Variables Associated With Fibrosis ≥ 2 (Present in 246 Patients, 25 Among Lean and 221 Among Overweight/Obese) at Multivariate Analysis in Lean or Overweight/Obese NAFLD

Results : Factors Related to More Severe Liver and Cardiovascular Disease Multivariable Analysis Table 4. Variables Associated With cplaques (Present in 201 Patients, 26 Among Lean and 175 Among Overweight/Obese) at Multivariate Analysis in Lean or Overweight/Obese NAFLD

Results : Role of Visceral Obesity

Results : Role of Visceral Obesity Lean NAFLD with higher WC Compared with overweight/obese group DM, cplaques, fibrosis score of 2 or greater Not reach significance Compared with non-visceral obesity NASH, fibrosis score of 2 or greater, MetS, cplaques Reach significance

Results : Adiponectin, Adipose Tissue Insulin Resistance Lean patient : higher adiponectin Patients (overall, overweight/obese) with NASH : lower adiponectin, not significant Adipose tissue insulin resistance Overweight/obese Visceral obesity (higher WC) Patients with NASH : even each lean and overweight/obese Adjusting for age, sex : Correlated with NASH / not fibrosis score of 2 or greater, carotid plaques

Discussion Conflicting data in lean NAFLD Lean NAFLD Asian NAFLD 1) 17% Severe liver damage : NASH, fibrosis score of 2 or higher 27% Carotid plaques Conflicting data in lean NAFLD Asian NAFLD 1) 20%, by magnetic resonance spectroscopy 43% NASH, by NAS score 3 or greater US NAFLD 2) 7%, by ultrasonography 0.1% NASH, by increased ALT level + DM / Insulin resistance 1) Wei JL, Leung JC, Loong TC, et al. Prevalence and severity of nonalcoholic fatty liver disease in non-obese patients: a population study using proton-magnetic resonance spectroscopy. Am J Gastroenterol 2015;110:1306–1314; quiz 1315. 2) Younossi ZM, Stepanova M, Negro F, et al. Nonalcoholic fatty liver disease in lean individuals in the United States. Medicine (Baltimore) 2012;91:319–327.

Discussion Lean NAFLD with Higher WC DM, cplaques, fibrosis score of 2 or greater Coronary artery disease : worse survival at normal weight with central obesity than normal/overweight/obese without central obesity 3) Ectopic fat accumulation : associated with Insulin resistance Proinflammatory cytokines Endothelial dysfunction Inflammatory gene : increased with the progression of histologic liver damage 3) Coutinho T, Goel K, Correa de Sa D, et al. Combining body mass index with measures of central obesity in the assessment of mortality in subjects with coronary disease: role of “normal weight central obesity”. J Am Coll Cardiol 2013;61:553–560.

Discussion Lean NAFLD with PNPLA3 polymorphism PNPLA3 GG polymorphism : only independent variable associated with NASH, fibrosis score of 2 or greater  More severe liver damage No differences prevalence of gene : lean vs overweight/obese PNPLA3 GG polymorphism More susceptible to environmental factors : manifest liver disease Associated significantly with NASH in lowest WC Maybe major role in lean NAFLD with lower WC Future study with larger number of patients needed

Discussion Limitation Strength Relatively small number Not quantify the cytokines related between fatty liver and cardiovascular disease Strength Availability of a well-characterized cohort of patients, with contemporary assessment of liver histology, cardiovascular damage Subset of Caucasian, other factors than metabolic alteration could play a role

Conclusion 20% of patients with lean NAFLD to have NASH, significant fibrosis (score 2 or greater), carotid atherosclerosis Genetic polymorphism play a key role in the severity of disease, but data preliminary Prompt the genetic characterization of lean patients with NAFLD to confirm this hypothesis

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