Antifibrotic activity of bevacizumab on human Tenon's fibroblasts in vitro

To evaluate the effect of the anti-VEGF-A monoclonal antibody bevacizumab on primary human Tenon's capsule fibroblasts (HTFs) in an in vitro model of wound healing.

Fibroblasts were cultured in RPMI media, and bevacizumab was administered at a concentration ranging from 0.25 to 12.5 mg/mL. Fibroblast viability and cell death were assessed using the MTT colorimetric assay, lactate dehydrogenase assay, BrdU assay, and live/dead assay. Fibroblast contractility was assessed in floating collagen gels. Morphologic changes were assessed by transmission electron microscopy. Antifibrosis activities were compared with 5-fluorouracil.

Bevacizumab induced a significant dose-related reduction of HTF cell number at 12.5 mg/mL at 72 hours (P < 0.05). Under serum-free conditions, bevacizumab induced significant fibroblast cell death at concentrations greater than 7.5 mg/mL (P < 0.05). Bevacizumab caused a moderate inhibition of fibroblast gel contraction from baseline (P < 0.05). Scanning electron microscopy revealed marked vacuolization in bevacizumab-treated fibroblasts.

Bevacizumab disrupted fibroblast proliferation, inhibited collagen gel contraction ability, and induced fibroblast cell death at concentrations greater than 7.5 mg/mL in serum-free conditions. These results demonstrated that bevacizumab inhibited a number of fibrosis activities in culture. These activities may underpin the antifibrosis effect proposed in vivo.