Influence of Race and Age on Aqueous Humor Levels of Transforming Growth Factor-Beta 2 in Glaucomatous and Nonglaucomatous Eyes

Purpose: To evaluate the influence of race and age on aqueous humor levels of transforming growth factor-beta 2 (TGF-beta 2). Methods: Patients >40 years of age and undergoing cataract or glaucoma surgery without associated significant intraocular pathology were selected for this study. In bilateral cases, only the first operated eye was included for evaluation. At the time of surgery, a small amount of aqueous was withdrawn. The concentration of total TGF-beta 2 was measured by enzyme-linked immunosorbent assay in duplicate by a masked observer. Results: Fifty-five aqueous humor samples were analyzed from subjects with an average age of 68.05 +/- 10.94 years. Overall median TGF-beta 2 concentration was 247.03 pg/mL. The median concentration of TGF-beta 2 was higher in eyes with glaucoma than in eyes without glaucoma (269.39 vs. 165.56 pg/mL, respectively; P = 0.001). Subgroup analysis found no significant difference between African American and Caucasian American subjects in the nonglaucomatous or glaucomatous subgroups. Age showed positive correlation with TGF-beta 2 in nonglaucomatous eyes (r(2) = 0.44, P = 0.019). No correlation between age and TGF-beta 2 was noted in the glaucoma group (r(2) = 0.02, P = 0.343). Conclusion: The aqueous humor concentration of TGF-beta 2 was significantly higher in eyes with glaucoma than in eyes without glaucoma. No significant difference between the aqueous humor levels of TGF-beta 2 from African American and Caucasian American subjects could be measured. However, a significant and positive correlation between age and aqueous humor concentration of TGF-beta 2 in the eyes of nonglaucomatous subjects was measured. These results are consistent with the idea that elevated levels of TGF-beta 2 within the anterior segment contribute to the development of glaucoma. In addition, the increased risk for developing glaucoma as one ages may in part be related to the rise of this cytokine.