title: Effect of blended CO2 and erbium:YAG laser irradiation on normal and keloid fibroblasts: a serum-free study.
abstract: OBJECTIVE
  The purpose of this study was to determine the effect of combined CO2 and Er:YAG laser irradiation on normal (NF) and keloid (KF) facial dermal fibroblast production of TGF-beta1 and bFGF.
  
  
  BACKGROUND
  Keloids produce excess collagen. TGF-beta1 is integral to the growth and stimulation of fibroblasts and collagen; bFGF inhibits collagen synthesis. TGF-beta1 and bFGF production influence wound healing and may be manipulated by laser irradiation.
  
  
  METHODS
  Human normal fibroblasts (NF) and keloid fibroblasts (KF) (2 x 10(4) cells/mL in serum-free media) were exposed to 1.7 J/pulse Er:YAG laser energy and CO2 delivered at either 3 or 5 W and at a duty cycle of 25%, 50%, or 100%. TGF-beta1 and bFGF were assayed using a quantitative ELISA.
  
  
  RESULTS
  KF demonstrated a statistically significant mean population doubling time (PDT) when compared with NF (p=0.01). Irradiated KF and NF had longer PDTs than controls. All NF, excluding one irradiated group, and the three KF treated with 3 W secreted more bFGF than controls. Irradiated KF secreted less TGF-beta1 than controls. Significance was reached with the two groups exposed to 3 W at a duty cycle of 25% and 50% (p=0.04 and 0.05, respectively). All irradiated NF secreted less TGF-beta1 than controls.
  
  
  CONCLUSIONS
  The combined CO2 and Er:YAG laser increased the release of bFGF, which has been shown to promote tightly organized collagen bundles, and decreased the concentration of TGF-beta1, which has also been shown to promote fibrosis formation. This laser may have a future role in keloid treatment, as well as normal facial scar prevention.
authors.affiliation: Wound Healing and Tissue Engineering Laboratory, Division of Otolaryngology-Head and Neck Surgery, Stanford University Medical Center, Stanford, California 94305-5328, USA.
authors.forename: Elbert T
authors.initials: ET
authors.lastname: Cheng
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Pollard
authors.forename: R James
authors.initials: RJ
authors.lastname: Koch
mesh_terms: D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D005347:Fibroblasts / Q000528:radiation effects*; D006801:Humans; D007627:Keloid / Q000628:therapy*; D053685:Laser Therapy
chemical_list: D016895:Culture Media, Serum-Free