Evaluation of Retinal Pigment Epithelial Cell Cytotoxicity of Recombinant Tissue Plasminogen Activator Using Human-Induced Pluripotent Stem Cells

[Modern aspects of the treatment of submacular hemorrhages secondary to macular degeneration]

Age-related macular degeneration complicated by submacular hemorrhage if not treated timely leads to permanent loss of central vision. The basis of effective therapy is its early start, dislocation of blood from central parts of the retina and blockage of neovascularization. This review examines the current methods of treatment of submacular hemorrhages, anatomical and functional outcomes, risks of postoperative complications, as well as trends in the use of combined methods of surgical intervention.

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.

Clinical Characteristics of Neovascular Age-Related Macular Degeneration without Typical Drusen

Purpose

To evaluate the clinical characteristics of neovascular age-related macular degeneration (nAMD) patients without typical drusen.

Methods

We retrospectively studied 165 eyes in 165 patients with treatment-naïve nAMD, including typical AMD and polypoidal choroidal vasculopathy (PCV). According to the fellow eye condition, the patients were divided into nAMD with and without typical drusen groups. Eyes with soft drusen or subretinal drusenoid deposits were classified into the nAMD with the typical drusen group. Smoking status and diagnoses of hypertension and diabetes were identified from hospital records and patient recall. We assessed best-corrected visual acuity (BCVA), central retinal thickness (CRT) at the fovea, subfoveal choroidal thickness (SFCT), and the number of injections received.

Results

The nAMD without typical drusen group was significantly younger (77.9 ± 7.6 vs. 71.8 ± 8.3, P < 0.001) and had thicker SFCT at baseline (207.9 ± 99.5 vs. 260.1 ± 113.2 μm, P=0.007) and a higher proportion of PCV (30.6 vs. 63.1%, P < 0.001). The proportion of ever-smokers was significantly higher in the nAMD without typical drusen group (54.8 vs. 70.9%, P=0.036). There were no statistically significant differences in the proportion of patients with hypertension or diabetes; BCVA, CRT, or SFCT changes; or the number of injections between the nAMD with and without typical drusen groups.

Conclusion

The clinical features of patients in the nAMD without typical drusen group were almost identical to those of pachychoroid-driven choroidal neovascularization (CNV) patients. The nAMD without typical drusen group had a significantly higher proportion of ever-smokers than the nAMD with typical drusen group. Smoking could be a risk factor for the development of pachychoroid-driven CNV.