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. Purpose: To evaluate the changes of vascular endothelial growth factor (VEGF) plasma levels after intravitreal injections of ranibizumab or bevacizumab in patients with exudative age-related macular degeneration (AMD). Methods: Forty-three patients with exudative AMD and 19 age- and sex-matched control patients without chorioretinal diseases were studied. Nineteen patients were treated with intravitreal ranibizumab 0.5 mg, 24 with intravitreal bevacizumab 1.25 mg. Blood samples were collected just before the first injection, and 28 days after three initial consecutive injections performed in 4-weekly intervals (loading dose). Concentration of VEGF in the plasma was measured by ELISA. Results: At baseline, the median VEGF concentrations in controls were 180.97 pg/ml, in the bevacizumab group 189.72 pg/ml and in the ranibizumab group 191.36 pg/ml. VEGF plasma concentrations in patients with wet AMD were comparable to controls (p = 0.225). Twenty-eight days after the third injection, a significant reduction of 42% in the median VEGF plasma levels was found in bevacizumab-treated patients (109.97 pg/ml; p = 0.0002) but not in ranibizumab-treated patients (189.97 pg/ml; p = 0.198) where a reduction of 0.7% in the median value was found. Conclusions: Intravitreal bevacizumab significantly reduced VEGF plasma levels until 28 days after intravitreal injection in patients with exudative AMD. Ranibizumab did not achieve a significant plasma VEGF reduction at the same time-point. These findings alert to the potential systemic safety differences between the two drugs after intravitreal administration. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to elucidate the precise effects of bevacizumab in all steps in the neovascularization process in endothelial cells. Methods: Human umbilical vein endothelial cells (HUVECs) were incubated with bevacizumab at concentrations within the clinically established range or with identical amounts of excipient. Cell cytotoxicity (evaluated by MTT assay), proliferation (by BrdU incorporation assay), apoptosis (by TUNEL assay), migration (by double-chamber assay) and vessel assembly in matrigel-coated plates were assessed in vitro. Mouse plug matrigel assays were performed to confirm in vitro results. Results: Incubation of HUVECs with bevacizumab did not present cytotoxicity. Concentrations comparable with those after intravitreal doses of bevacizumab significantly reduced proliferation and migration capacity, and increased apoptotic rates in these cells. In addition, bevacizumab led to a significant decrease in the assembly of capillary-like structures on matrigel assay in comparison with excipient-treated cells. Further substantiating these in vitro findings, bevacizumab also inhibited angiogenesis in a mouse plug matrigel assay, as evaluated by haemoglobin content levels. Conclusions: These results demonstrate that clinical doses of bevacizumab are able to prevent several steps of the angiogenic process. Bevacizumab is thus currently recommended for treating disorders that present augmented angiogenesis. [ABSTRACT FROM AUTHOR]