Multiple effects of bevacizumab in angiogenesis: implications for its use in age-related macular degeneration.

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]