title: Effect of blended carbon dioxide and erbium:YAG laser energy on preauricular and ear lobule keloid fibroblast secretion of growth factors: a serum-free study.
abstract: BACKGROUND
  A serum-free in vitro model was used to determine the effect of combined carbon dioxide (CO2) and erbium (Er):YAG laser (Derma K; ESC/Sharplan Medical Systems, Yokneam, Israel) irradiation on keloid-producing fibroblasts (KFs) from 2 distinct facial sites. Transforming growth factor beta1 (TGF-beta1) and basic fibroblast growth factor (bFGF) play an integral part in wound healing and were assayed using this model. It has always been a clinical impression that fibroblasts from different regions of the face behave differently. This is exemplified by patients prone to lobule keloid formation after ear piercing, who heal normally after a facial incision.
  
  
  METHODS
  Laboratory-based wound healing.
  
  
  METHODS
  Human KF cell lines were established from operative specimens using standard explant techniques. At 48 hours after seeding, 20% of each well was exposed to 1.7 J/pulse of Er:YAG laser energy and CO2 delivered at 3 or 5 W and at a duty cycle of 25%, 50%, or 100%. Using a quantitative enzyme-linked immunosorbent assay, TGF-beta1 and bFGF were assayed from collected supernatants.
  
  
  RESULTS
  Laser-treated ear lobule KFs demonstrated decreased TGF-beta1 production when compared with preauricular KFs. Statistical significance (P<.005) was seen in the 3-W CO2 25% duty cycle; a trend was seen in the 3-W CO2 50% duty cycle (P<.08). Preauricular KFs secreted increased bFGF when compared with lobule KFs. Significance was seen in the 3-W CO2 25% and 50% duty cycles (P<.05). Laser-treated preauricular KFs had increased bFGF secretion when compared with non-laser-treated preauricular KFs in the 3-W CO2 25%, 50%, and 100% duty cycles.
  
  
  CONCLUSIONS
  Combined CO2 and Er:YAG laser treatment decreases the production of TGF-beta1 in preauricular and ear lobule KFs. This laser may have clinical promise in the treatment of keloids. Finally, the different growth factor profiles obtained suggest that KFs from the ear lobule and preauricular regions are different.
authors.affiliation: Wound Healing and Tissue Engineering Laboratory, Division of Otolaryngology-Head and Neck Surgery, R-135, Stanford University Medical Center, Stanford, CA 94305-5328, USA.
authors.forename: E T
authors.initials: ET
authors.lastname: Cheng
authors.forename: K C
authors.initials: KC
authors.lastname: Nowak
authors.forename: R J
authors.initials: RJ
authors.lastname: Koch
mesh_terms: D002245:Carbon Dioxide; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D004431:Ear, External; D004797:Enzyme-Linked Immunosorbent Assay; D004871:Erbium; D016222:Fibroblast Growth Factor 2 / Q000096:biosynthesis*; D005347:Fibroblasts / Q000378:metabolism* / Q000528:radiation effects; D006801:Humans; D007627:Keloid / Q000378:metabolism* / Q000532:radiotherapy; D007834:Lasers; D016212:Transforming Growth Factor beta / Q000096:biosynthesis*; D053773:Transforming Growth Factor beta1
chemical_list: D016895:Culture Media, Serum-Free; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D016222:Fibroblast Growth Factor 2; D002245:Carbon Dioxide; D004871:Erbium