title: Weight gain reveals dramatic increases in skeletal muscle extracellular matrix remodeling.
abstract: BACKGROUND
  In animal models of obesity, chronic inflammation and dysregulated extracellular matrix remodeling in adipose tissue leads to insulin resistance. Whether similar pathophysiology occurs in humans is not clear.
  
  
  OBJECTIVE
  The aim of this study was to test whether 10% weight gain induced by overfeeding triggers inflammation and extracellular matrix remodeling (gene expression, protein, histology) in skeletal muscle and sc adipose tissue in humans. We also investigated whether such remodeling was associated with an impaired metabolic response (hyperinsulinemic-euglycemic clamp).
  
  
  METHODS
  Twenty-nine free-living males were fed 40% over their baseline energy requirements for 8 weeks.
  
  
  RESULTS
  Ten percent body weight gain prompted dramatic up-regulation of a repertoire of extracellular matrix remodeling genes in muscle and to a lesser degree in adipose tissue. The amount of extracellular matrix genes in the muscle were directly associated with the amount of lean tissue deposited during overfeeding. Despite weight gain and impaired insulin sensitivity, there was no change in local adipose tissue or systemic inflammation, but there was a slight increase in skeletal muscle inflammation.
  
  
  CONCLUSIONS
  We propose that skeletal muscle extracellular matrix remodeling is another feature of the pathogenic milieu associated with energy excess and obesity, which, if disrupted, may contribute to the development of metabolic dysfunction.
authors.affiliation: Pennington Biomedical Research Center (C.S.T., J.D.C., S.B., Y.T., D.B., D.L.J., E.R.), Baton Rouge, Louisiana 70808; The Charles Perkins Centre and School of Biological Sciences (C.S.T.), University of Sydney, Sydney, 2006 New South Wales, Australia; Department of Kinesiology (S.B.), University of Texas at El Paso, El Paso, Texas 79968; and Department of Experimental and Clinical Medicine-Obesity Center (C.M.Z., S.C.), United Hospitals-University of Ancona, Ancona 60020, Italy.
authors.forename: Charmaine S
authors.initials: CS
authors.lastname: Tam
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Covington
authors.forename: Sudip
authors.initials: S
authors.lastname: Bajpeyi
authors.forename: Yourka
authors.initials: Y
authors.lastname: Tchoukalova
authors.forename: David
authors.initials: D
authors.lastname: Burk
authors.forename: Darcy L
authors.initials: DL
authors.lastname: Johannsen
authors.forename: Cristina M
authors.initials: CM
authors.lastname: Zingaretti
authors.forename: Saverio
authors.initials: S
authors.lastname: Cinti
authors.forename: Eric
authors.initials: E
authors.lastname: Ravussin
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism* / Q000473:pathology; D000328:Adult; D005109:Extracellular Matrix / Q000378:metabolism* / Q000473:pathology; D015309:Glucose Clamp Technique; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D007333:Insulin Resistance / Q000502:physiology; D050356:Lipid Metabolism / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D015430:Weight Gain / Q000502:physiology*