Bevacizumab modulates the process of fibrosis in vitro

Abstract

Background: Fibrosis is the most common side effect after anti-vascular epithelial growth factor (VEGF) therapy (intravitreal bevacizumab) for retinal or choroidal neovascularization. This study was to investigate the efficacy of bevacizumab on the expressions of fibrosis-related cytokines in human umbilical vein endothelial cells (HUVECs) in vitro.

Methods: Cultured HUVECs were divided into groups of controls (group 1), hypoxia (group 2) and hypoxia combined with bevacizumab (group 3). No treatment was given in group 1. In group 2, cobalt(II) chloride (CoCl₂) (200 μm) was added to the medium. In group 3, in addition to CoCl₂, bevacizumab was mixed in the medium, with a final concentration of 0.25 mg/mL, roughly equal to the concentration used clinically. The expressions of connective tissue growth factor (CTGF), transforming growth factor-β₂ (TGF-β₂) and basic fibroblast growth factor-2 (bFGF-2) were evaluated by SYBR green real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay at 6 h, 12 h, 24 h and 48 h. Matrix metalloproteinases (MMP)-2 was detected by SYBR green real-time PCR and Western blotting at each time point.

Results: Both messenger RNA and protein levels of CTGF, bFGF, TGF-β₂ and MMP-2 in group 2 were higher than group 1 (P < 0.05). In group 3, the expressions of CTGF, bFGF, TGF-β₂ and MMP-2 were upregulated compared with group 2 (P < 0.05).

Conclusions: Bevacizumab at clinical doses can exert pro-fibrotic effects on HUVECs by upregulating the expressions of CTGF, bFGF, TGF-β₂ and MMP-2. This may be involved in fibrosis after anti-VEGF therapy.

Keywords: anti-VEGF; bevacizumab; cytokines; fibrosis.