title: Hypertrophic scar fibroblasts have increased connective tissue growth factor expression after transforming growth factor-beta stimulation.
abstract: BACKGROUND
  Hypertrophic scars and keloids respond to dermal disruption with excessive collagen deposition and increased transforming growth factor (TFG)-beta expression. Connective tissue growth factor (CTGF) is a downstream mediator of TGF-beta activity that is associated with scar and fibrosis. The authors hypothesize that there is increased expression of CTGF by hypertrophic scar and keloid fibroblasts in response to TGF-beta stimulation.
  
  
  METHODS
  Primary fibroblasts were isolated in culture from human hypertrophic scar (n = 2), keloid (n = 2), and normal skin (n = 2). After 18 hours of serum starvation, the cells were stimulated with 10 ng/ml of TGF-beta1, TGF-beta2, and TGF-beta3 for 24 hours. Quantitative real-time polymerase chain reaction was performed on extracted RNA samples to assay for CTGF mRNA expression.
  
  
  RESULTS
  Baseline CTGF expression was increased 20-fold in unstimulated hypertrophic scar fibroblasts and 15-fold in keloid fibroblasts compared with normal fibroblasts. CTGF expression increased greater than 150-fold when stimulated with TGF-beta1 (p < 0.002) and greater than 100-fold when stimulated by TGF-beta2 or TGF-beta3 compared with normal fibroblasts (p < 0.02 and p < 0.002, respectively). CTGF expression was greatest after TGF-beta1 stimulation in hypertrophic scar fibroblasts compared with TGF-beta2 (p < 0.04) and TGF-beta3 (p < 0.02). Keloid fibroblast CTGF expression also increased greater than 100-fold after stimulation with TGF-beta1 (p = 0.16) and greater than 75-fold after addition of TGF-beta2 and TGF-beta3 (p = 0.06 and p = 0.22, respectively).
  
  
  CONCLUSIONS
  Hypertrophic scar fibroblasts have both intrinsic up-regulation of CTGF transcription and an exaggerated capacity for CTGF transcription in response to TGF-beta stimulation. These data suggest that blockage of CTGF activity may reduce pathologic scar formation.
authors.affiliation: Division of Plastic Surgery, Department of Surgery, Children's Surgical Research Program, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Amy S
authors.initials: AS
authors.lastname: Colwell
authors.forename: Toan-Thang
authors.initials: TT
authors.lastname: Phan
authors.forename: Wuyi
authors.initials: W
authors.lastname: Kong
authors.forename: Michael T
authors.initials: MT
authors.lastname: Longaker
authors.forename: Peter H
authors.initials: PH
authors.lastname: Lorenz
mesh_terms: D000328:Adult; D002478:Cells, Cultured; D002648:Child; D017439:Cicatrix, Hypertrophic / Q000378:metabolism*; D055513:Connective Tissue Growth Factor; D005260:Female; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D017874:Immediate-Early Proteins / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D007627:Keloid / Q000378:metabolism; D008297:Male; D016212:Transforming Growth Factor beta / Q000502:physiology*
chemical_list: C526317:CCN2 protein, human; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D016212:Transforming Growth Factor beta; D055513:Connective Tissue Growth Factor