Effect of bevacizumab (Avastin™) on mitochondrial function of in vitro retinal pigment epithelial, neurosensory retinal and microvascular endothelial cells.

Purpose: To evaluate the effect of bevacizumab on the mitochondrial function of human retinal pigment epithelial (ARPE‑19), rat neurosensory retinal (R28) and human microvascular endothelial (HMVEC) cells in culture. Materials and Methods: ARPE‑19 and R28 cells were treated with 0.125, 0.25, 0.50 and 1 mg/ml of bevacizumab. The HMVEC cultures were treated with 0.125, 0.25, 0.50 and 1 mg/ml of bevacizumab or 1 mg/ml of immunoglobulin G (control). Mitochondrial function assessed by mitochondrial dehydrogenase activity (MDA) was determined using the WST‑1 assay. Results: Bevacizumab doses of 0.125 to 1 mg/ml for 5 days did not significantly affect the MDA of ARPE‑19 cells. Bevacizumab treatment at 0.125 and 0.25 mg/ml (clinical dose) did not significantly affect the MDA of R28 cells; however, 0.50 and 1 mg/ml doses significantly reduced the R28 cell mitochondrial function. All doses of bevacizumab significantly reduced the MDA of proliferating and non‑proliferating HMVEC. Conclusion: Bevacizumab exposure for 5 days was safe at clinical doses in both ARPE‑19 and R28 retinal neurosensory cells in culture. By contrast, bevacizumab exposure at all doses show a significant dose‑dependent decrease in mitochondrial activity in both the proliferating and non‑proliferating HMVEC in vitro. This suggests a selective action of bevacizumab on endothelial cells at clinical doses.

Effects of hydroquinone on retinal and vascular cells in vitro.

Aim: To explore the molecular pathophysiology that might explain the epidemiologic association between cigarette smoke and age-related macular degeneration (AMD) by examining the effects of hydroquinone (HQ), a toxic compound present in high concentration in cigarette smoke-related tar, on human retinal pigment epithelial cells (ARPE-19), rat retinal neurosensory cells (R-28), and human microvascular endothelial cells (HMVEC). Materials and Methods: ARPE-19, R-28, and HMVEC were treated for 24 h with four different concentrations of HQ (500 μM, 200 μM, 100 μM, 50 μM). Cell viability, caspase-3/7 activation, DNA laddering patterns, and lactate dehydrogenase (LDH) levels were analyzed. Results: At 50 μM HQ, R-28 cells showed a significant decrease in cell viability compared with the dimethyl sulfoxide (DMSO)-treated controls. At the 100–500 μM concentrations, all three cell lines showed significant cell death (P < 0.001). In the ARPE-19, R-28, and HMVEC cultures, the caspase-3/7 activities were not increased at any of the HQ concentration. Conclusion: Our findings suggest that the mechanism of cell death in all three cell lines was through non-apoptotic pathway. In addition, neuroretinal R-28 cells were more sensitive to HQ than the ARPE-19 and HMVEC cultures.