title: Influence of argon laser trabeculoplasty on transforming growth factor-beta 2 concentration and bleb scarring following trabeculectomy.
abstract: BACKGROUND
  The purpose of this study was to evaluate the influence of previous argon laser trabeculoplasty (ALT) on transforming growth factor-beta 2 (TGF-beta 2) concentration of the aqueous humor and its influence on bleb scarring after trabeculectomy.
  
  
  METHODS
  Fifty-one patients with primary open-angle glaucoma (POAG) and 29 patients with exfoliation (XFS) glaucoma were recruited for this prospective study before undergoing trabeculectomy. Sixty to 200 micro l of aqueous humor were analyzed for total and biologically active TGF-beta 2 concentrations (R and D Systems). TGF-beta 2 levels and a standardized bleb assessment were compared between the ALT- and non-ALT-treated groups.
  
  
  RESULTS
  POAG eyes without ALT showed significantly higher total TGF-beta 2 levels (2,317.7+/-1,041.1 pg/ml) than eyes with previous ALT (1,621.6+/-899.6 pg/ml; P=0.026). No significant difference was found for active TGF-beta 2 levels (ALT: 238.1+/-119.0 pg/ml; no ALT: 220.1+/-96.9 pg/ml; P=0.585). In XFS patients ALT did not alter total TGF-beta 2 levels (ALT: 1,524.9+/-624.9 pg/ml, no ALT: 1,220+/-499.1 pg/ml; P=0.20), but active TGF-beta 2 was significantly higher in the ALT-treated (237.0+/-99.7 pg/ml) than in the non-ALT-treated (140.0+/-95.3 pg/ml, P=0.028) group. Bleb grading revealed no statistical difference between the ALT- and non-ALT-treated groups in POAG (P=0.545, Fisher's exact test), whereas XFS patients with ALT were at increased risk for scarring compared to non-ALT-treated patients (P=0.053).
  
  
  CONCLUSIONS
  ALT appears to increase the risk of scarring in XFS patients because of increased levels of activated TGF-beta 2.
authors.affiliation: Department of Ophthalmology, Julius Maximilian University Würzburg, Joseph-Schneider-Str. 11, 97080 Würzburg, Germany. wimmer_i@klinik.uni-wuerzburg.de
authors.forename: Iris
authors.initials: I
authors.lastname: Wimmer
authors.forename: Ulrich
authors.initials: U
authors.lastname: Welge-Luessen
authors.forename: Greda
authors.initials: G
authors.lastname: Picht
authors.forename: Franz
authors.initials: F
authors.lastname: Grehn
mesh_terms: D001082:Aqueous Humor / Q000378:metabolism*; D001128:Argon; D001768:Blister / Q000150:complications; D002921:Cicatrix / Q000209:etiology*; D017889:Exfoliation Syndrome / Q000601:surgery*; D005902:Glaucoma, Open-Angle / Q000601:surgery*; D006801:Humans; D053685:Laser Therapy / Q000009:adverse effects*; D009994:Osmolar Concentration; D011446:Prospective Studies; D012307:Risk Factors; D014130:Trabeculectomy / Q000009:adverse effects* / Q000379:methods; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D053781:Transforming Growth Factor beta2
chemical_list: C509041:TGFB2 protein, human; D016212:Transforming Growth Factor beta; D053781:Transforming Growth Factor beta2; D001128:Argon