In Vitro Effects of Antivascular Endothelial Growth Factors on Cultured Human Trabecular Meshwork Cells

PURPOSE: To investigate the effects of a neutralizing vascular endothelial growth factor antibody and antibody fragment as well as vehicle components on primary cultures of human trabecular meshwork (TM) cells. METHODS: Assays of cellular metabolism were performed using the diphenyl tetrazolium bromide assay in confluent cultures of cells. Proliferative effects were determined by measuring 5'-bromo-2'-deoxyuridine uptake in subconfluent cultures of cells. RESULTS: Twenty-four-hour treatment with 4 mg/mL bevacizumab reduced TM metabolism to 34.4 ± 12.4% (mean ± SD) as compared with human immunoglobulin G controls (P<0.0001). 4 mg/mL bevacizumab also reduced TM cell proliferation to 62.7 ± 9.2% of controls (P<0.0001). No significant decrease was seen at 2 mg/mL bevacizumab, or with molar equivalents of the related anti-vascular endothelial growth factor agent ranibizumab. Exposure of TM cells to the components of bevacizumab and ranibizumab vehicle did not lead to significant antimetabolic effects. CONCLUSIONS: Our data reveal that high concentrations of bevacizumab are harmful to TM cells in vitro whereas no such effect was noted with human immunoglobulin G controls or ranibizumab. Further studies are needed to better understand the antimetabolic effects of higher concentrations of bevacizumab on intraocular cell lines and whether smaller concentrations may have a similar effect on TM cells after repeated exposures.