Purpose: The aim of the study is to explore the interaction between stimulators and inhibitors of angiogenesis by measuring pigment epithelium-derived factor (PEDF) and vascular endothelial growth factor (VEGF) plasma levels in patients with the wet and dry forms of age-related macular degeneration (AMD).
Material and methods: Forty-six subjects with the wet form, 31 with the dry form of AMD as well as 47 non-AMD healthy controls were enrolled in the study. Plasma concentrations of VEGF and PEDF were measured using ELISA test.
Results: A significant decrease in the PEDF plasma level in patients with the dry form of AMD was found. Multivariate analyses of patients and controls adjusted for age, sex, smoking, and concomitant vascular diseases as independent variables revealed that the dry form of AMD was the only independent factor associated with lower plasma PEDF levels (beta = -0.34; p = 0.026). On the contrary, in the wet AMD group, a strong positive correlation between VEGF and PEDF concentrations was observed (Rs = +0.63; p = 0.002), and significantly higher PEDF and VEGF plasma levels in patients with bilateral manifestations of the disease were also found.
Conclusions: These findings suggest that different manifestations of AMD, i.e. the dry and wet forms, may be associated with various altered concentrations of counterbalancing stimulators and inhibitors of the angiogenesis process.