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

Sankarathi Balaiya, Jayson Edwards, Tina Tillis, Vijay Khetpal, Kakarla V Chalam
University of Florida College of Medicine, Department of Ophthalmology Jacksonville, FL, USA

Purpose: Tumor necrosis factor alpha (TNF-α), a macrophage/monocyte derived pluripotent cytokine is associated with tissue ischemia, neuronal damage and remodeling. The physiological level of TNF-α in aqueous humor of normal and glaucomatous eyes is unknown. In this study, we evaluated the TNF- α levels in aqueous in patients with primary open angle glaucoma (POAG) and compared them to controls.
Methods: 50–100 µL 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-α levels were quantified using singleplex bead immunoassay analysis.
Results: The average TNF-α level in POAG samples was 2.72 ± 1.5 pg/mL (mean ± SD). The average TNF-α level in normal samples was 1.59 ± 0.46 pg/mL (mean ± SD). Significant increase of TNF-α levels in POAG samples was noted in comparison to normal samples (P < 0.001).
Conclusion: TNF-α levels are elevated in aqueous in patients with POAG compared to normal subjects based on highly sensitive Luminex^® bead immunoassay and may be a reliable biomarker in the progression of glaucoma.

Keywords: TNF-α, POAG, aqueous humor, cytokine