Choroidal Neovascular Membrane in Age-Related Macular Degeneration is Associated with Increased Interleukin-6

Abstract

Age-related macular degeneration (AMD) is the leading cause of irreversible visual impairment and blindness among persons aged 60 years and older. Although inflammation has been postulated to have a role in the pathogenesis of AMD, epidemiologic studies have not shown a relationship between systemic inflammation or presence of inflammatory markers at AMD. The aim of our study was to evaluate the differences in various types of cytokines and intracelluler signaling molecules for the onset and progression of AMD. There were two groups in our study; Group 1, which acted as the control group ( n = 30, mean age 67.60 ± 8.32 years), and Group 2, consisting of AMD patients ( n = 22, mean age 70.10 ± 10.33 years). From serum samples, vascular endothelial growth factor (VEGF) (pg/mL), interleukin-6 (IL-6) and interleukin-1β (IL-1β) (pg/mL), nitrotyrosine (nmol/L) levels were determined by enzyme linked-immuno-sorbent assay method. Nitrite/Nitrate levels were measured by photometric method (μmol/L). There were no significant differences between the groups with regard to age, VEGF, IL-1β, nitrite/nitrate, and nitrotyrosine. The significant result was the mean IL-6 levels that were higher in the AMD group (55.03 ± 60.03 pg/mL) than in the control group (16.08 ± 8.24 pg/mL, p < 0.001). IL-6 induces an ocular inflammatory response often accompanied by the breakdown of the blood–ocular barrier. The increased levels of IL-6 can support the hypothesis that AMD may be partially mediated through inflammatory mechanisms.