Abstract
Abstract: :
Purpose: To evaluate the influence of previous Argon Laser Trabeculoplasty (ALT) on Transforming Growth Factor beta-2 (TGF-ß2) concentration in the aqueous humor and its influence on bleb scarring after trabeculectomy. Methods: Eighty patients (51 POAG, 29 PEX eyes) were recruited for this prospective study before undergoing first (n=77) or second (n=3) trabeculectomy. Previous ALT was performed in 27 patients (20 POAG, 7 PEX.) between 9 months and 6 years prior to trabeculectomy . 129 patients with cataract surgery served as control. 60-200 microliter of aqueous humor were analysed for total and biologically active TGF-ß2 concentration using a double-antibody "sandwich" ELISA kit (R&D Systems, MN). Postoperative mean follow up was 8,7 months. TGF-ß2 level and standardized bleb assessment were compared between the ALT and non -ALT treated group. Statistic analysis was performed using t-test and Fisher's exact test. Results: In POAG eyes no significant difference was found for active TGF-ß2 level between the ALT treated (238.1 +/- 119.0 pg/ml) and non-ALT treated group (220.1 +/- 96.9 pg/ml; p= 0.585). Total TGF-ß2 level were statistically significant higher in patients without ALT (2317.7 +/- 1041.1 pg/ml) than eyes with previous ALT (1621.6 +/- 899.6 pg/ml; p=0.026). In contrast to POAG patients, active TGF-ß2 level in PEX eyes were statistically significant higher in the ALT treated group (237.0 +/- 99.7 pg/ml) than in the non-ALT treated group (140.0 +/- 95.3 pg/ml, p= 0.028). ALT did not alter total TGF-ß2 level in PEX patients (ALT: 1524.9 +/-624.9 pg/ml, no ALT: 1220 +/- 499.1 pg/ml; p =0.20). Total and active TGF-ß2 concentration in the control group were 1658.1 +/- 573.7 pg/ml and 183.6 +/- 86.8 pg/ml respectively. Evaluation of bleb scarring revealed no significant difference between the ALT and non-ALT treated group in POAG (p=0.545, Fisher's exact test) whereas PEX patients with ALT were at increased risk for scarring compared to non-ALT treated patients although statistical significance was borderline ( p= 0.053, Fisher's exact test). Conclusion: In our study, POAG eyes with previous ALT do not show different active TGF-ß2 level in aqueous humor and do not have an increased risk for scarring when compared to non-ALT pretreated patients. In contrast, ALT appears to increase the risk of scarring in PEX patients, possibly by ALT induced TGF-ß2 release from the trabecular endothelium, which is a source of TGF-ß2 production.
Keywords: 631 wound healing • 423 growth factors/growth factor receptors • 601 trabecular meshwork