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Martina Kropp, Argyrios Chronopoulos, Alain Conti, Nina Harmening, Séverine Pouillot, Corinne Marie, Daniel Scherman, Zsuzsanna Izsvák, Pablo Aranda, Verónica Fernández, Gabriele Thumann; Results of a biodistribution study of Venus transfected pigment epithelial cells transplanted subretinally in rabbits. Invest. Ophthalmol. Vis. Sci. 2016;57(12):1187.
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© 2017 Association for Research in Vision and Ophthalmology.
Age-related macular degeneration (AMD) is a major cause of blindness in the elderly in developed countries. For the neovascular form, which mainly results from elevated levels of vascular endothelial growth factor (VEGF), treatment with frequent, life-long injections of anti-VEGFs restores vision in about 30-40% of patients. A consortium of European Universities and industry is developing a gene-therapeutic alternative. In 2 phase Ib/IIa clinical trials, autologous iris (IPE) or retinal pigment epithelial (RPE) cells will be harvested from a patient, transfected with the human gene for pigment epithelium-derived factor (hPEDF), an antagonist of VEGF, using the Sleeping Beauty (SB100X) transposon system delivered in pFAR4-miniplasmids, and transplanted subretinally in the patient to inhibit choroidal neovascularization. Here we report on the distribution of the transplanted cells in tissues away from the eye after various times of follow-up.
Primary rabbit RPE and IPE cells were transfected with the SB100X transposase and the green fluorescent Venus gene encoded in pFAR4-miniplasmids using a new developed electroporation buffer. Transfection efficiency was determined by image-based cytometry. 20’000 transfected cells were transplanted subretinally into the left eye of Chinchilla Bastard rabbits. 43 organs from brain and eye to heart, lung, and liver to peripheral nerve and bone marrow were dissected and their gross appearance recorded. Biopsies from 24 selected organs were fixed in ice-cold ethanol and prepared for cryosection. The slides were analyzed by fluorescence microscopy.
Rabbit RPE and IPE cells were efficiently transfected as evidenced by the number of 31.2±5.9% fluorescent cells. Careful dissection revealed no abnormal findings in any organ of rabbits transplanted with transfected cells. Analysis of the tissues by fluorescence microscopy did not detect any florescence or fluorescent cells in any tissue than the injection site.
Since no fluorescence was observed, the results presented here show that either the secreted Venus protein or the transfected RPE or IPE cells transplanted subretinally migrate systemically.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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