Clinical and Immunological Analysis of Retinal Pigment Epithelium Transplantation Derived from Induced Pluripotent Stem Cells under Pharmacological Immunosuppression in Rabbits

Abstract

justification. Degenerative retinal diseases associated with retinal pigment epithelium damage are untreated and lead to irreversible vision loss. The most promising approach nowadays is considered to be the transplantation of retinal pigment epithelium differentiated from pluripotent stem cells (PSC-RPE). When testing biomedical cellular products, special requirements are placed on the animal model, which should simulate pathological changes, such as in humans, and have sufficient immunological tolerance to xenogenic human cells, enabling them to function fully. For this purpose, lines of immuno-modified or immunodeficiency animals are used, usually small rodents (rats and mice), but the small size and structure of their eyes do not allow manipulation in vitreoretinal interventions in humans. An alternative method of preventing xenotransplantation rejection in large models is pharmacological immunosuppression, under which transplanted PSC-RPE may have biological effects. However, targeted studies of the effectiveness of PSC-RPE transplantation with use of immunosuppressive therapy have not been conducted in our country, and the data of a few foreign works devoted to this problem are contraversial.Purpose. Study of immunological reactivity in transplantation of IPSC-RPE under combined immunosuppressive therapy in rabbit experiment.Materials and methods. The study was performed on 27 male rabbits of New Zealand albino breed, of which 24 animals underwent subretinal transplantation of induced pluripotent stem cells of retinal pigment epithelium: in the I group (12 eyes) intervention was performed in the healthy eye; in group II (12 eyes) — in the area of pre-modeled atrophy of retinal pigment epithelium. Recipients were given combined immunosuppressive therapy. Control Group — 3 intact rabbits (6 eyes). The observation period was 14, 28 and 60 days. Post-transplant evaluation was carried out using standard and specialized ophthalmological examination methods. The determination of cytokines of the immune response IL-2, IL-6, immunosuppressive factors TGF-β1, TGF-β2, TSP-1 in the serum of the blood and the vitreous body was performed by solid-phase immunosurgical enzyme analysis.Results. Comprehensive analysis of biomicroscopy, ophthalmoscopy, optical coherent tomography, immunological studies revealed no signs of active inflammation; no local and systemic increase in the concentration of acute phase IL-6, a drop in serum IL-2 levels indicated direct effects of immunosuppressive drug combinations used in this study.Conclusion. The use of combined immunosuppressive therapy prevented rejection of xenogenic material in rabbits and obtained evidence of safety of subretinal transplantation of IPSC-RPE suspension both in the healthy eye, and pre-induced atrophy of pigmentary epithelium.