Circulating insulin-like growth factor-1: a new clue in the pathogenesis of age-related macular degeneration

In order to investigate Insulin-like growth factor-1 (IGF-1) blood levels in male and female age-matched patients affected by early, intermediate, neovascular age related macular degeneration (AMD) and healthy subjects (no AMD) were enrolled in a prospective, observational study. All patients enrolled were classified according to 4 stages classification of AMD from Age-related eye disease study (AREDS). Each subject underwent a complete ophthalmic examination including best corrected visual acuity (BCVA), applanation tonometry, slit-lamp biomicroscopic examination, color fundus photography, optical coherence tomography (OCT) and, if needed, fluorescein angiography. Overall, 224 anti-VEGF naïve subjects including 56 patients in early AMD group, 56 patients in intermediate AMD group, 56 patients in neovascular AMD group and 56 patients in no AMD group were recruited. For each group 28 male patients and 28 female patients were enrolled. IGF-1 hematic levels were significantly higher (p<0.005) in the neovascular AMD group and in the intermediate AMD group in comparison to no AMD group; no significant difference between early AMD group and no AMD group was found. Our analysis has shown an increment of IGF-1 levels in both neovascular and intermediate stage of AMD supporting the hypothesis that IGF-1 may play a role in the pathogenesis of AMD.