Tanja Ilmarinen1, Fabian Thieltges2, Heidi Hongisto1,3, Kati Juuti-Uusitalo1, Arto Koistinen4, Kai Kaarniranta3,5, Ralf Brinken2, Norbert Braun6, Frank G Holz2, Heli Skottman1, Boris V Stanzel2. 1. BioMediTech Institute, Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland. 2. Department of Ophthalmology, University of Bonn, Bonn, Germany. 3. Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland. 4. SIBS Labs, University of Eastern Finland, Kuopio, Finland. 5. Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland. 6. Geuder AG, Heidelberg, Germany.
Abstract
PURPOSE: To study immunogenic properties of human embryonic stem cell-derived retinal pigment epithelium (hESC-RPE) and to evaluate subretinal xenotransplantation of hESC-RPE on porous polyethylene terephthalate (PET) in rabbits. METHODS: Human ESC-RPE cells were characterized by morphology, transepithelial electrical resistance (TER), protein expression and photoreceptor outer segment phagocytosis in vitro. Expression of major histocompatibility complex (MHC) proteins was assessed in conventionally or xeno-free produced hESC-RPE ± interferon-gamma (IFN-γ) stimulation (n = 1). Xeno-free hESC-RPE on PET with TER < 200 Ω·cm2 > or PET alone were transplanted into 18 rabbits with short-term triamcinolone ± extended tacrolimus immunosuppression. Rabbits were monitored by spectral domain optical coherence tomography. After 4 weeks, the eyes were processed for histology and transmission electron microscopy. RESULTS: Upon in vitro IFN-γ stimulation, xeno-free hESC-RPE expressed lower level of MHC-II proteins compared to the conventional cells. Outer nuclear layer (ONL) atrophy was observed over the graft in most cases 4 weeks post-transplantation. In 3/4 animals with high TER hESC-RPE, but only in 1/3 animals with low TER hESC-RPE, ONL atrophy was observed already within 1 week. Retinal cell infiltrations were more frequent in animals with high TER hESC-RPE. However, the difference was not statistically significant. In three animals, preservation of ONL was observed. Weekly intravitreal tacrolimus did not affect ONL preservation. In all animals, hESC-RPE cells survived for 4 weeks, but without tacrolimus, enlarged vacuoles accumulated in hESC-RPE (n = 1). CONCLUSIONS: Xenografted xeno-free hESC-RPE monolayers can survive and retain some functionality for 4 weeks following short-term immunosuppression. The preliminary findings of this study suggest that further investigations to improve transplantation success of hESC-RPE xenografts in rabbits should be addressed especially toward the roles of hESC-RPE maturation stage and extended intravitreal immunosuppression.
PURPOSE: To study immunogenic properties of human embryonic stem cell-derived retinal pigment epithelium (hESC-RPE) and to evaluate subretinal xenotransplantation of hESC-RPE on porous polyethylene terephthalate (PET) in rabbits. METHODS:Human ESC-RPE cells were characterized by morphology, transepithelial electrical resistance (TER), protein expression and photoreceptor outer segment phagocytosis in vitro. Expression of major histocompatibility complex (MHC) proteins was assessed in conventionally or xeno-free produced hESC-RPE ± interferon-gamma (IFN-γ) stimulation (n = 1). Xeno-free hESC-RPE on PET with TER < 200 Ω·cm2 > or PET alone were transplanted into 18 rabbits with short-term triamcinolone ± extended tacrolimus immunosuppression. Rabbits were monitored by spectral domain optical coherence tomography. After 4 weeks, the eyes were processed for histology and transmission electron microscopy. RESULTS: Upon in vitro IFN-γ stimulation, xeno-free hESC-RPE expressed lower level of MHC-II proteins compared to the conventional cells. Outer nuclear layer (ONL) atrophy was observed over the graft in most cases 4 weeks post-transplantation. In 3/4 animals with high TER hESC-RPE, but only in 1/3 animals with low TER hESC-RPE, ONL atrophy was observed already within 1 week. Retinal cell infiltrations were more frequent in animals with high TER hESC-RPE. However, the difference was not statistically significant. In three animals, preservation of ONL was observed. Weekly intravitreal tacrolimus did not affect ONL preservation. In all animals, hESC-RPE cells survived for 4 weeks, but without tacrolimus, enlarged vacuoles accumulated in hESC-RPE (n = 1). CONCLUSIONS: Xenografted xeno-free hESC-RPE monolayers can survive and retain some functionality for 4 weeks following short-term immunosuppression. The preliminary findings of this study suggest that further investigations to improve transplantation success of hESC-RPE xenografts in rabbits should be addressed especially toward the roles of hESC-RPE maturation stage and extended intravitreal immunosuppression.
Authors: Zengping Liu; Bhav Harshad Parikh; Queenie Shu Woon Tan; Daniel Soo Lin Wong; Kok Haur Ong; Weimiao Yu; Ivan Seah; Graham E Holder; Walter Hunziker; Gavin S W Tan; Veluchamy Amutha Barathi; Gopal Lingam; Boris V Stanzel; Timothy A Blenkinsop; Xinyi Su Journal: Stem Cell Reports Date: 2021-01-14 Impact factor: 7.765
Authors: Zengping Liu; Tanja Ilmarinen; Heli Skottman; Boris V Stanzel; Gavin S W Tan; Heidi Hongisto; Edmund Y M Wong; Andrew S H Tsai; Sami Al-Nawaiseh; Graham E Holder; Xinyi Su; Veluchamy Amutha Barathi Journal: Stem Cell Res Ther Date: 2021-07-27 Impact factor: 6.832