Clinical Ophthalmology (Apr 2018)
Association of increased levels of plasma tumor necrosis factor alpha with primary open-angle glaucoma
Abstract
Altaf A Kondkar, Tahira Sultan, Faisal A Almobarak, Hatem Kalantan, Saleh A Al-Obeidan, Khaled K Abu-Amero Glaucoma Research Chair, Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia Purpose: Retinal ganglion cell (RGC) death is a key feature of glaucoma. Elevated levels of tumor necrosis factor alpha (TNF-α), a pro-inflammatory cytokine, can induce RGC apoptosis and play a critical role in glaucomatous neurodegeneration. Based on the possible role of inflammation and oxidative stress in the pathogenesis of primary open-angle glaucoma (POAG), we investigated the association between plasma levels of TNF-α and POAG or its clinical indices in comparison to non-glaucomatous controls. Patients and methods: In a case–control retrospective cohort of 51 POAG cases and 88 controls, plasma TNF-α levels were measured using an enzyme-linked immunosorbent assay (ELISA). The assay was performed in duplicates on an automated ELISA analyzer. Results: Mean TNF-α level was significantly elevated in POAG cases (1.88 ± 2.17 pg/mL) than the controls (0.93 ± 1.49 pg/mL; p = 0.003). The overall dose–response trend was significant (Χ2 = 6.12, df = 2; p = 0.047). No statistical difference was seen in age, gender and systemic disease distribution. A modest negative and significant correlation was seen between TNF-α level and number of antiglaucoma medications, an important clinical index of POAG severity. Moreover, logistic regression analysis showed that the risk of POAG was most significantly affected by TNF-α level and not by age and sex. Conclusion: High systemic level of an inflammatory cytokine, TNF-α, is associated with POAG; however, its possible use as a biomarker for early glaucoma diagnosis and/or disease severity needs further investigation. Keywords: apoptosis, biomarker, cytokines, ELISA, inflammation, neurodegeneration, oxidative stress
