Purchase this article with an account.
Y. Miura, F. Treumer, A. Klettner, J. Hillenkamp, R. Brinkmann, R. Birngruber, J. Roider; Vegf and Pedf Secretions Over Time Following Various Laser Irradiations on an Rpe Organ Culture. Invest. Ophthalmol. Vis. Sci. 2010;51(13):469.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To investigate the influences of different laser power settings for retinal photocoagulation (from sub- to over-threshold) on the secretion of growth factors from RPE.
RPE-choroid sheets (9 mm diameter) were isolated from freshly enucleated porcine eyes and cultivated in perfusion culture system. Laser irradiation was performed on the first day of cultivation (wavelength: 532nm, spot diameter: 300µm, irradiation time: 0.1ms, power: 20-120 mW, 120 spots per explant). The threshold laser power was determined using calcein-AM cell viability test directly after irradiation. From the next day on, the culture medium was collected daily until day 6 and the concentrations of vascular endothelial growth factor (VEGF) and pigment-epithelium derived factor (PEDF) were measured with Elisa assay. The wound healing was assessed using FITC-phalloidin staining to visualize the actin of RPE cells.
Under the condition described above, the threshold laser power for immediate RPE cell death was around 50 mW. Most of the RPE-defects by up to 120 mW were closed until day 4. The irradiation with 40 mW did not induce any immediate cell death, but the wound healing analysis disclosed that some small wound healing occurred after this laser power too, which suggests the late cell death. VEGF expression on day 1 was up-regulated in the cultures irradiated with over 40 mW in a dose-dependent manner. After that, the VEGF secretion declined gradually and reached the control level around day 3. The amount further decreased and showed a lower level than control on day 4 and 5. On day 6, the level came back to the control level. PEDF secretion was also up-regulated by over-threshold laser power on day 1 and then decreased on day 2, but again started to increase from day 3 and kept high level until day 6. With 40 mW, the PEDF secretion increased on day 2 significantly and then decreased to the control level.
The secretions of VEGF and PEDF from RPE are up-regulated by laser irradiation, even by sub-threshold laser power for immediate cell death. VEGF is up-regulated directly following the irradiation, while PEDF secretion increases over time. Considering these secretion patterns, it is assumed that VEGF is secreted by the cells heated by laser irradiation, while PEDF is secreted by the cells covering the wound or by the surrounding RPE cells secondarily-stimulated during wound healing.
This PDF is available to Subscribers Only