Cytotoxic effects of alteplase, a recombinant tissue plasminogen activator, on human retinal pigment epithelial cells

Purpose: To evaluate the cytotoxic effects of alteplase, a recombinant tissue plasminogen activator, and its additives on human retinal pigment epithelial (hRPE) cells. Study design: Laboratory study. Methods: We evaluated the cytotoxic effects of alteplase on human fetal RPE (hfRPE) cells, human induced pluripotent stem cell-derived RPE (hiPS-RPE), and ARPE-19 cells, as well as the cytotoxic effects of L-arginine and polysorbate 80, two additives of alteplase, on hfRPE cells. The effects of alteplase on the production of vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) from hfRPE cells and the transepithelial resistance (TER) of hiPS-RPE cells were also assessed. The type of cell death induced by alteplase was investigated using ethidium homodimer III and FITC-Annexin V staining and terminal transferase deoxyuridine triphosphatase nick-end labeling. Results: Alteplase reduced the viability of hfRPE cells significantly in a dose- and time-dependent manner. The reaction of hiPS-RPE and ARPE19 cells to alteplase was similar to that of hfRPE cells. Out of L-arginine and polysorbate 80, only treatment with L-arginine significantly reduced the viability of hfRPE cells. Alteplase (83 μg/ml, 6 h) had no significant effect on the production of VEGF and PEDF from hfRPE cells. Alteplase decreased the TER of hiPS-RPE cells in a dose- and time-dependent manner and induced necrosis as the type of cell death. Conclusion: Alteplase can be cytotoxic to human RPE cells in a concentration- and time-dependent manner, with L-arginine being a possible causative factor.