title: Systematic review of bariatric surgery liver biopsies clarifies the natural history of liver disease in patients with severe obesity.
abstract: Non-alcoholic fatty liver disease (NAFLD) is a frequent complication of morbid obesity, but its severity varies greatly and thus there is a strong need to better define its natural history in these patients.
  
  
  
  Liver biopsies were systematically performed in 798 consecutive patients with severe obesity undergoing bariatric surgery. Histology was compared with clinical, biological, anthropometrical and body composition characteristics.
  
  
  
  Patients with presumably normal liver (n=179, 22%) were significantly younger at bariatric surgery than patients with NAFLD (37.0 vs 44.4 years, p<0.0001). However, both groups showed quite similar obesity duration, since patients with presumably normal liver reported the onset of obesity at a significantly younger age than those with NAFLD (14.8 vs 20.0 year, p<0.0001). The trunk/limb fat mass ratio increased according to liver disease severity (presumably normal liver: 1.00, steatosis: 1.21, non-alcoholic steatohepatitis (NASH): 1.34, p<0.0001), although the total body fat mass decreased (presumably normal liver: 50%, steatosis: 49.1%, NASH: 47.4%, p<0.0001). The volume of subcutaneous adipocytes increased according to severity of liver disease but only in female patients (presumably normal liver: 8543 picolitres, steatosis: 9156 picolitres, NASH: 9996 picolitres).
  
  
  
  These results suggest that young adults are more prone to store fat in subcutaneous tissue and reach the threshold of bariatric surgery indication before their liver is damaged. A shift of fat storage from subcutaneous to visceral adipose tissue compartment is associated with liver damages. Liver might also be targeted by subcutaneous hypertrophic adipocytes in females since hypertrophic adipocytes are more exposed to lipolysis and to the production of inflammatory mediators.
authors.affiliation: Department of Pathology, Assistance Publique-Hôpitaux de Paris (AP-HP), Beaujon Hospital, INSERM U1149, University Paris-Diderot, Paris, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Bedossa
authors.affiliation: Nutrition Department, Institute of Cardiometabolism and Nutrition (ICAN), Pitié-Salpêtrière Hospital, (AP-HP), University Pierre et Marie Curie, Paris, France.|Université Pierre et Marie Curie, INSERM, UMRS 1166, NutriOmique team F-75015, Paris, France.
authors.forename: Joan
authors.initials: J
authors.lastname: Tordjman
authors.affiliation: Nutrition Department, Institute of Cardiometabolism and Nutrition (ICAN), Pitié-Salpêtrière Hospital, (AP-HP), University Pierre et Marie Curie, Paris, France.|Université Pierre et Marie Curie, INSERM, UMRS 1166, NutriOmique team F-75015, Paris, France.
authors.forename: Judith
authors.initials: J
authors.lastname: Aron-Wisnewsky
authors.affiliation: Nutrition Department, Institute of Cardiometabolism and Nutrition (ICAN), Pitié-Salpêtrière Hospital, (AP-HP), University Pierre et Marie Curie, Paris, France.|Université Pierre et Marie Curie, INSERM, UMRS 1166, NutriOmique team F-75015, Paris, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Poitou
authors.affiliation: Nutrition Department, Institute of Cardiometabolism and Nutrition (ICAN), Pitié-Salpêtrière Hospital, (AP-HP), University Pierre et Marie Curie, Paris, France.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Oppert
authors.affiliation: Department of Digestive and Hepato-Pancreato-Biliary Surgery, Assistance Publique-Hôpitaux de Paris (AP-HP), Pitié-Salpêtrière Hospital, Paris, France.
authors.forename: Adriana
authors.initials: A
authors.lastname: Torcivia
authors.affiliation: Surgery Department, Assistance Publique-Hôpitaux de Paris (AP-HP), Ambroise Paré Hospital, Boulogne-Billancourt, France.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Bouillot
authors.affiliation: Department of Pathology, Assistance Publique-Hôpitaux de Paris (AP-HP), Beaujon Hospital, INSERM U1149, University Paris-Diderot, Paris, France.
authors.forename: Valerie
authors.initials: V
authors.lastname: Paradis
authors.affiliation: Assistance Publique-Hôpitaux de Paris (AP-HP), Pitié-Salpêtrière Hospital, Liver Center, Université Pierre et Marie Curie, Paris, France.
authors.forename: Vlad
authors.initials: V
authors.lastname: Ratziu
authors.affiliation: Nutrition Department, Institute of Cardiometabolism and Nutrition (ICAN), Pitié-Salpêtrière Hospital, (AP-HP), University Pierre et Marie Curie, Paris, France.|Université Pierre et Marie Curie, INSERM, UMRS 1166, NutriOmique team F-75015, Paris, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Clément
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000367:Age Factors; D050110:Bariatric Surgery / Q000379:methods*; D001706:Biopsy; D006801:Humans; D008099:Liver / Q000473:pathology*; D065626:Non-alcoholic Fatty Liver Disease / Q000150:complications / Q000175:diagnosis / Q000473:pathology; D009767:Obesity, Morbid / Q000150:complications / Q000473:pathology / Q000601:surgery; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors
keywords: FATTY LIVER; LIVER BIOPSY; MORBID OBESITY