Association of increased levels of plasma tumor necrosis factor alpha with primary open-angle glaucoma

Abstract

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

Acknowledgments

The authors would like to thank the Deanship of Scientific Research and Glaucoma Research Chair of Department of Ophthalmology, College of Medicine, King Saud University, for their support and use of laboratory facilities. The funder had no role in the design of the study and collection, analysis and interpretation of data and in writing the manuscript. The article has not been presented in any previous conference or scientific meeting.

Author contributions

All authors contributed toward data analysis, drafting and revising the article and agreed to be accountable for all aspects of the work.

Disclosure

The authors have no conflict of interests in this work, and the study was not supported or funded by any drug company.