Tumor necrosis factor-alpha (TNF-alpha) levels in aqueous humor of primary open angle glaucoma

Purpose: Tumor necrosis factor alpha (TNF-alpha), a macrophage/monocyte derived pluripotent cytokine is associated with tissue ischemia, neuronal damage and remodeling. The physiological level of TNF-alpha in aqueous humor of normal and glaucomatous eyes is unknown. In this study, we evaluated the TNF-alpha levels in aqueous in patients with primary open angle glaucoma (POAG) and compared them to controls. Methods: 50-100 mu L of undiluted aqueous humor samples were obtained from eyes of 32 POAG patients who underwent cataract extraction, trabeculectomy or aqueous shunt implantation. Controls were obtained from 32 normal subjects who underwent routine cataract surgery. TNF-alpha levels were quantified using singleplex bead immunoassay analysis. Results: The average TNF-alpha level in POAG samples was 2.72 +/- 1.5 pg/mL (mean +/- SD). The average TNF-alpha level in normal samples was 1.59 +/- 0.46 pg/mL (mean +/- SD). Significant increase of TNF-alpha levels in POAG samples was noted in comparison to normal samples (P < 0.001). Conclusion: TNF-alpha levels are elevated in aqueous in patients with POAG compared to normal subjects based on highly sensitive Luminex (R) bead immunoassay and may be a reliable biomarker in the progression of glaucoma.