Abstract

DO.01.06

The effect of the various Anti-VEGF drugs on RPE in a cell culture model

Yoko Miura
Klinik für Ophthalmologie, Campus Kiel, Universitätsklinikum Schleswig-Holstein, Kiel

Objective: To investigate the influence of anti-VEGF drugs on the intracellular permeability of retinal pigment epithelium (RPE) and underlying mechanisms.
Methods: Second passage porcine RPE cells were cultured on 6 well membrane inserts. The cells were exposed to Bevacizumab (62.5 µg/ml) or Ranibizumab (25 µg/ml) for 24 hours (short-term) or for 9 days (long-term). On indicated days, the transepithelial flux of FITC-dextran and the intracellular total glutathione level were investigated. In order to clarify the glutathione consumption, the change of glutathione level was investigated under low glucose condition. The effect of glutathione depletion on RPE permeability was investigated using L-buthionine sulfoximine (BSO), a glutathione synthethase inhibitor.
Results: After the short-term exposure, Bevacizumab and Ranibizumab increased the transepithelial flux significantly on day 2. Bevacizumab had a prolonged effect for more than one week. Under long-term exposure, the flux-increase lasted more than one week both in Bevacizumab and Ranibizumab-treated cells. Bevacizumab had a stronger effect than Ranibizumab. A prominent fluctuation of glutathione level was observed after both Bevacizumab and Ranibizumab treatment for the first few days. Nine days after short and long-term treatment, Bevacizumab-treated cells showed a significant lower glutathione level, while Ranibizumab-treated cells exhibited levels similar to control. In the low glucose condition, Bevacizumab and Ranibizumab accelerated the decrease of intracellular total glutathione level for the first 48 hrs. Glutathione depletion increased the permeability of the RPE.
Conclusions: These results suggest that Bevacizumab and Ranibizumab enhance the permeability of the RPE, especially Bevacizumab leads a prolonged permeability increase. A significant fluctuation of intracellular glutathione level might relate to these facts. Since Bevacizumab and Ranibizumab increase the consumption of intracellular glutathione directly following the treatment, it is possible that they induce a slight oxidative stress in RPE cells. The prolonged increase of permeability and the significant decrease of total glutathione level in Bevacizumab-treated cells suggest that Bevacizumab has a prolonged harmful influence on RPE cells. These effects might be related to the Bevacizumab side effects, such as intraocular inflammation or RPE tear.

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