Apelin-13: A Promising Biomarker for Age-Related Macular Degeneration?

PURPOSE: To investigate the value of serum apelin-13 levels in patients with age-related macular degeneration (AMD). METHODS: Patients with dry-type AMD, patients with treatment-naïve neovascular-type AMD, and healthy controls were included in this study. Diagnoses were confirmed on detailed fundus examination, optical coherence tomography (OCT), and fundus fluorescein angiography (FFA). Central foveal thickness and subfoveal choroidal thickness were evaluated. Both serum apelin-13 and vascular endothelial growth factor (VEGF) levels were measured by a competitive enzyme-linked immunosorbent assay (ELISA) principle. RESULTS: A total of 84 subjects, i.e., 24 in the dry-type AMD group (group 1), 27 in the neovascular-type AMD group (group 2), and 33 in the control group (group 3) were included in the study. Mean best-corrected visual acuity (BCVA) was 76 ± 4.5, 48.4 ± 16.3, and 83.4 ± 3.09 ETDRS letters in group 1, 2, and 3, respectively. The level of serum VEGF was 44.11 ± 26.14, 56.53 ± 53.77, and 61.47 ± 41.62 pg/mL in groups 1, 2, and 3, respectively (p = 0.553, p = 0.286, and p = 0.896, respectively). The level of serum apelin-13 was 586.47 ± 167.56, 622.18 ± 324.52, and 379.31 ± 171.96 pg/mL in groups 1, 2, and 3, respectively (p = 0.847, p = 0.04, and p ≤ 0.001, respectively). There was a negative correlation between the level of serum apelin and visual acuity (VA) and choroidal thickness. CONCLUSION: Serum apelin-13 levels were higher in both dry-type and neovascular-type AMD patients than in controls. Further studies demonstrating the relationship of the level of serum apelin-13 and AMD are needed.