Endothelial Progenitor Cells and Plasma Vascular Endothelial Growth Factor and Stromal Cell-Derived Factor-1 During Ranibizumab Treatment for Neovascular Age-Related Macular Degeneration

Abstract

To evaluate endothelial progenitor cell [late outgrowth endothelial progenitor cells (OECs)], vascular endothelial growth factor (VEGF), and stromal cell-derived factor 1α (SDF-1α) plasma levels as potential biomarkers before and during ranibizumab (Lucentis(®)) treatment for neovascular age-related macular degeneration (nvAMD). Thirty-one patients with untreated nvAMD presenting for 3 consecutive intravitreal ranibizumab injections and a follow-up visit at 4 weeks intervals were enrolled. Peripheral blood was collected before each injection and at the follow-up visit and OEC clusters were cultured and evaluated according to previously published protocols. VEGF and SDF-1α plasma levels were measured by enzyme-linked immunosorbent assay and compared to values from healthy young and old control. Patients with a high OEC count before treatment presented significantly more often with a short symptom duration and a smaller choroidal neovascularization size. VEGF plasma levels were significantly higher in nvAMD (282.4±195.2 pg/mL) compared to young (45.5±6.8 pg/mL) and old control (46.1±8.5 pg/mL). OEC levels decreased nonsignificantly during ranibizumab treatment, returning to baseline levels after the third injection. VEGF and SDF-1α plasma levels decreased significantly during treatment toward control values. Patients needing retreatment after 3 ranibizumab injections had significantly higher VEGF plasma levels at pretreatment compared to patients not needing further treatment. The results presented here suggest that VEGF plasma levels may warrant further evaluation regarding biological, therapeutical, and predictive implications in nvAMD.