title: Up-regulation of PPAR-gamma mRNA expression in the liver of obese patients: an additional reinforcing lipogenic mechanism to SREBP-1c induction.
abstract: BACKGROUND
  Triglyceride accumulation in the liver is an early feature in the development of nonalcoholic fatty liver disease (NAFLD) associated with human obesity, which is a multifactorial syndrome and whose underlying mechanisms are beginning to be understood.
  
  
  OBJECTIVE
  Liver peroxisome proliferator-activated receptor-γ (PPAR-γ) mRNA expression was measured as a signaling mechanism related to steatosis in obese patients with NAFLD.
  
  
  METHODS
  Liver PPAR-γ and sterol receptor element-binding protein 1c (SREBP-1c) mRNA (real-time RT-PCR), serum total adiponectin (RIA), and high molecular weight (HMW)-adiponectin (ELISA) levels, and insulin resistance (IR) evolution (homeostasis model assessment-IR) were determined in 22 obese NAFLD patients (16 with steatosis and six with steatohepatitis) who underwent subtotal gastrectomy with gastrojejunal anastomosis in Roux-en-Y and 16 nonobese subjects who underwent laparoscopic cholecystectomy (controls).
  
  
  RESULTS
  Liver PPAR-γ mRNA levels were 112 and 188% higher (P < 0.05) than control values in obese patients with steatosis and steatohepatitis, respectively, who also exhibited 70 and 62% increases in those of SREBP-1c, concomitantly with IR and lower levels of serum total adiponectin and HMW-adiponectin (P < 0.05). Liver PPAR-γ expression showed positive associations with SREBP-1c mRNA levels (r = 0.86; P < 0.0001), serum insulin levels (r = 0.39; P < 0.01), and homeostasis model assessment-IR (r = 0.60; P < 0.0001), and negative correlations with total adiponectin (r = -0.37; P < 0.01) and HMW-adiponectin (r = -0.51; P < 0.001) levels in serum.
  
  
  CONCLUSIONS
  PPAR-γ is up-regulated in the liver of obese patients with NAFLD, representing an additional reinforcing lipogenic mechanism to SREBP-1c induction in the development of hepatic steatosis.
authors.affiliation: Department of Food Science, Nutrition, and Dietetics, Faculty of Pharmacy, University of Concepción, Casilla 237, Concepción, Chile. ppettinelli@udec.cl
authors.forename: Paulina
authors.initials: P
authors.lastname: Pettinelli
authors.forename: Luis A
authors.initials: LA
authors.lastname: Videla
mesh_terms: D052242:Adiponectin / Q000096:biosynthesis / Q000097:blood; D000328:Adult; D000713:Anastomosis, Roux-en-Y; D005234:Fatty Liver / Q000378:metabolism; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D008099:Liver / Q000378:metabolism*; D008297:Male; D008970:Molecular Weight; D009765:Obesity / Q000378:metabolism* / Q000601:surgery; D047495:PPAR gamma / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051780:Sterol Regulatory Element Binding Protein 1 / Q000096:biosynthesis*
chemical_list: D052242:Adiponectin; D047495:PPAR gamma; D012333:RNA, Messenger; D051780:Sterol Regulatory Element Binding Protein 1