title: Subcutaneous adipose tissue remodeling during the initial phase of weight gain induced by overfeeding in humans.
abstract: BACKGROUND
  Deciphering the early processes occurring in adipose tissue during weight gain is a major issue for understanding the development of fat mass and obesity. Experimental overfeeding in humans is a unique situation to tackle these events.
  
  
  OBJECTIVE
  Our aim was to identify the pathways involved in sc adipose tissue remodeling during the initial phase of weight gain.
  
  
  METHODS
  Forty-four healthy men were involved in an overfeeding protocol with a lipid-enriched diet (+760 kcal/d) for 2 months. Subcutaneous abdominal adipose tissue biopsies were taken for histology, transcriptomics, and Western blotting in the basal state, after 14 d, and at the end of the protocol.
  
  
  RESULTS
  Overfeeding significantly increased body weight (+2.5 kg) and fat mass. Reorganization of gene expression patterns occurred in adipose tissue with an up-regulation of numerous genes involved in lipid metabolism and storage, followed by clusters of genes related to angiogenesis and extracellular matrix remodeling. Histological examination showed increased microvascular density and connective tissue deposition after 56 d of overfeeding, with no changes in the number of macrophages or inflammatory cells. Inhibition of the canonical Wnt/β-catenin signaling pathway and induction of the renin-angiotensin system might be implicated in the remodeling of sc adipose tissue.
  
  
  CONCLUSIONS
  We characterize the coordinated and time-dependent processes that occur in human adipose tissue during the early phase of weight gain in healthy subjects and identify pathways representing potential targets in pathologies of adipose development, including obesity.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale Unit 1060, CarMeN Laboratory and Centre Européen Nutrition Santé, Lyon 1 University, F-69600 Oullins, France.
authors.forename: M
authors.initials: M
authors.lastname: Alligier
authors.forename: E
authors.initials: E
authors.lastname: Meugnier
authors.forename: C
authors.initials: C
authors.lastname: Debard
authors.forename: S
authors.initials: S
authors.lastname: Lambert-Porcheron
authors.forename: E
authors.initials: E
authors.lastname: Chanseaume
authors.forename: M
authors.initials: M
authors.lastname: Sothier
authors.forename: E
authors.initials: E
authors.lastname: Loizon
authors.forename: A Ait
authors.initials: AA
authors.lastname: Hssain
authors.forename: J
authors.initials: J
authors.lastname: Brozek
authors.forename: J-Y
authors.initials: JY
authors.lastname: Scoazec
authors.forename: B
authors.initials: B
authors.lastname: Morio
authors.forename: H
authors.initials: H
authors.lastname: Vidal
authors.forename: M
authors.initials: M
authors.lastname: Laville
mesh_terms: D050154:Adiposity / Q000235:genetics / Q000502:physiology; D000293:Adolescent; D000328:Adult; D004435:Eating / Q000235:genetics / Q000502:physiology; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D046228:Microarray Analysis; D008875:Middle Aged; D044343:Overnutrition / Q000150:complications / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology*; D015398:Signal Transduction / Q000235:genetics; D050507:Subcutaneous Fat, Abdominal / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors; D015430:Weight Gain / Q000235:genetics / Q000502:physiology*; D055815:Young Adult