Abstract
Purpose :
Clinical testing for molecular biomarkers can help prediction and early diagnosis of glaucoma and monitoring treatment responses. Based on the present evidence of increased oxidative stress in glaucomatous tissues, this study aimed to determine the specificity and diagnostic/prognostic value of oxidative stress-related candidates as molecular biomarkers of glaucoma. Although biomarker screening in blood samples is a common and logical choice, analysis of more proximal fluids, such as aqueous humor, may be advantages to gain glaucoma-specific information. This study was therefore designed for comparative analysis of various markers of oxidative stress in blood and aqueous humor samples.
Methods :
Blood and aqueous humor samples were collected from 137 patients with glaucoma and 124 control subjects without glaucoma (with or without other ocular diseases). The samples were analyzed for oxidative stress markers, including protein carbonyl and HNE content, antioxidant enzymes, and advanced glycation end products, through targeted quantification assays. The ratios of aqueous humor-to-blood levels of the studied oxidative stress markers were calculated in individual patients and study groups with different types (including primary open-angle glaucoma with normal or high intraocular pressure, and exfoliative glaucoma) and different stages of glaucoma (from ocular hypertension to early, moderate, and advanced stages of structure and function loss) and non-glaucomatous controls. The multivariate logistic regression analysis then evaluated the effects of multiple covariates, such as age, race, sex, intraocular pressure level, glaucoma-related injury parameters (including standard automated perimetry and retinal imaging scores), treatments, and systemic diseases.
Results :
Among the studied biomarker candidates in blood and aqueous humor samples, the ratios of aqueous humor-to-blood levels of protein carbonyls and advanced glycation end products presented the most significant association to glaucoma (p=0.007, p=0.001 respectively).
Conclusions :
Findings of this study provide clinically applicable information towards molecular biomarkers of glaucoma and encourage further validation studies in larger and heterogeneous cohorts.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.