Abstract
Purpose :
Growth/Differentiation Factor-15 (GDF-15), also known as Macrophage inhibitory cytokine-1 has been characterized as a stress response protein, and marker of ageing and neurodegenerative glaucoma. In this study, we quantified GDF-15 levels in the aqueous humor from primary open-angle glaucoma (POAG) human patients to evaluate the possible relationship between GDF-15 and intraocular pressure (IOP).
Methods :
Aqueous humor samples were collected from POAG (n=67) and age- and gender-matched cataract (n=75) patients during surgery performed at the Duke Eye Center. GDF-15 protein levels in aqueous humor samples were determined using a human GDF-15 specific ELISA kit. The study was IRB approved.
Results :
GDF-15 protein levels (392 ± 54.6 pg/ml) were significantly (p≤0.001) elevated in the aqueous humor of POAG patients compared to non-glaucoma (cataract) patients (52.6 ± 6.09 pg/ml). In POAG patients, the elevated levels of aqueous humor GDF-15 correlated positively and significantly (p≤0.05) with increased IOP. Demographic comparisons amongst POAG subjects indicated that GDF-15 levels did not differ by gender or race (Caucasian or African-American), and were not correlated with age. Furthermore, there were no significant differences in aqueous humor GDF-15 protein levels between POAG patients being treated with different IOP lowering medications.
Conclusions :
This study reveals significantly elevated (>7 folds) levels of GDF-15 in the aqueous humor of POAG patients which correlated positively with IOP changes. These findings warrant further studies to determine the role of GDF-15 in the etiology of ocular hypertension and aqueous humor drainage through the trabecular meshwork.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.