Elevated TGF-beta levels in aqueous humor of human eyes with failed filtration bleb

Purpose. Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine that has been implicated to be the key mediator of fibrosis associated with various pathologic conditions. This study investigated the possible role of TGF-beta in the pathogenesis of glaucoma and development of failed filtration blebs. Methods. Aqueous humor was obtained intraoperatively from the following groups of patients: (a) patients undergoing cataract surgery with no other ocular condition (n=6); (b) patients undergoing cataract surgery with medically controlled POAG and no other ocular condition (n=5); (c) patients undergoing cataract surgery with POAG controlled with a filtration bleb and no other ocular condition (n=5); (d) patients with POAG with failed filtration bleb undergoing a molteno valve placement (n=4). The level of active and total TGF-beta2 was measured in the aqueous humor aspirate using ELISA techniques. Results. There was no significant difference in the level of active or total TGF-beta2 in eyes with medically controlled POAG when compared to non-glaucomatous eyes. In contrast, eyes with a functioning filtration bleb had significantly lower total TGF-beta2 when compared to eyes without filtration bleb, and eyes with a failed filtration bleb had significantly higher level of active and total TGF-beta2 when compared to the other three groups. Conclusions. A rise in the level of TGF-beta2 in the aqueous humor is associated with the development of filtration bleb failure. The possible role of TGF-beta in the pathogenesis of filtration bleb failure needs to be further investigated.