Abstract
Purpose :
The role of glial cell line-derived neurotrophic factor (GDNF) in pathogenesis of primary open-angle glaucoma (POAG) is not clear. The aim of the study was to measure the content of GDNF in the aqueous humor, lacrimal fluid, and blood serum in patients with POAG and age-related cataract.
Methods :
We examined 30 patients (30 eyes) with POAG and age-related cataract. Forty-seven previously examined patients of similar age and sex with age-related cataract (47 eyes) served as a control (Shpak AA, et al. IOVS 2021, 62; ARVO e-abstract 718). Collection of stimulated lacrimal fluid was performed by a pipette on the day preceding surgery; the aqueous humor of the anterior chamber and the blood were sampled during the phacoemulsification of a cataract. The concentration of GDNF was measured using an enzyme immunoassay RayBio® Human GDNF ELISA Kit (RayBiotech, USA) on a ChemWell 2910 automatic analyzer (Awareness Technology Inc., USA).
Results :
Compared to controls, at the earlier stages of POAG (stages 1-2 according to classification by Mills et al., 2006), GDNF concentration (median [interquartile range]) was significantly decreased (P<0.05 – P<0.001) in all studied biological fluids: in aqueous humor (46 [14-57] vs. 83 [59-119]), lacrimal fluid (176 [96-238] vs. 314 [244-422]) and serum (163 [128-202] vs. 196 [174-239]) pg/mL. In later stages 3-4, the GDNF levels increased, however, in the aqueous humor and lacrimal fluid remained significantly reduced in comparison with controls. An inverse correlation with the perimetric index VFI was found for the content of GDNF in lacrimal fluid (r=-0.47; P=0.01) and serum (r=-0.40; P=0.03); a direct correlation was found between the GDNF levels in serum and aqueous humor (r=0.47; P=0.01).
Conclusions :
In patients with POAG, GDNF level in the aqueous humor, lacrimal fluid, and blood serum is significantly decreased, especially in the earlier stages of the disease. In subsequent stages, reduction of GDNF level in the aqueous humor and lacrimal fluid is less pronounced, however the level of GDNF in these media remains significantly reduced compared to patients without glaucoma. An inverse correlation with the perimetric index VFI was found for the content of GDNF in lacrimal fluid and blood serum, as well as a direct correlation of GDNF levels in the blood serum and aqueous humor.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.