title: Evolution of subcutaneous adipose tissue fibrosis after bariatric surgery.
abstract: OBJECTIVE
  Obesity is associated with the development of metabolic complications such as insulin resistance (IR). The mechanisms leading to IR remain unclear. This study aimed to investigate the relationship between adipose tissue fibrosis and IR in obese patients before and after bariatric surgery.
  
  
  METHODS
  Thirty-five obese patients awaiting bariatric surgery (12 with type 2 diabetes) were included in the study. Non-diabetic patients were classified as either insulin-sensitive (n=11) or insulin-resistant (n=12), based on the Matsuda insulin sensitivity index (ISIMatsuda). Homoeostasis model assessment (HOMA-IR) was used for longitudinal evaluation of insulin resistance. Fibrosis was quantified by Masson's trichrome staining on microscopy, and mRNA levels of fibrosis-related genes were examined in subcutaneous (SAT) and visceral adipose tissue (VAT) biopsies collected during and 6 months after bariatric surgery (SAT only).
  
  
  RESULTS
  Despite their similar age, body mass index and fat mass, SAT fibrosis was significantly higher in diabetic vs insulin-sensitive patients (P<0.05), and associated with IR as assessed by both ISIMatsuda(r=-0.417, P=0.038) and HOMA-IR (r=0.464, P=0.007) at baseline, whereas VAT fibrosis was not. Six months after surgery and significant weight loss, fibrosis levels remained unchanged in SAT, although IR was significantly reduced in all groups (P<0.0001). No correlation was found between SAT fibrosis and IR after surgery.
  
  
  CONCLUSIONS
  Overall, these results show a significant but, most likely, transient association between SAT fibrosis and IR in obese humans.
authors.affiliation: Department of Nutrition, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada; Institut de Recherches Cliniques de Montréal (affiliated to the Université de Montréal), 110, avenue des Pins-Ouest, Montréal, QC H2W 1R7, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Chabot
authors.affiliation: Institut de Recherches Cliniques de Montréal (affiliated to the Université de Montréal), 110, avenue des Pins-Ouest, Montréal, QC H2W 1R7, Canada.
authors.forename: M-S
authors.initials: MS
authors.lastname: Gauthier
authors.affiliation: General Surgery, Hôpital du Sacré-Coeur de Montréal, Montréal, QC H4J 1C5, Canada.
authors.forename: P Y
authors.initials: PY
authors.lastname: Garneau
authors.affiliation: Department of Nutrition, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada; Institut de Recherches Cliniques de Montréal (affiliated to the Université de Montréal), 110, avenue des Pins-Ouest, Montréal, QC H2W 1R7, Canada. Electronic address: remi.rabasa-lhoret@ircm.qc.ca.
authors.forename: R
authors.initials: R
authors.lastname: Rabasa-Lhoret
mesh_terms: D000328:Adult; D050110:Bariatric Surgery; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000473:pathology* / Q000601:surgery; D005260:Female; D005355:Fibrosis / Q000473:pathology; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000473:pathology* / Q000601:surgery; D050151:Subcutaneous Fat / Q000473:pathology*
keywords: Adipose tissue; Fibrosis; Insulin resistance; Metabolically healthy obese (MHO); Obesity