A Systematic Review on Transplantation Studies of the Retinal Pigment Epithelium in Animal Models
The retinal pigment epithelium (RPE) and the adjacent light-sensitive photoreceptors form a single functional unit lining the back of the eye. Both cell layers are essential for normal vision. RPE degeneration is usually followed by photoreceptor degeneration and vice versa. There are currently almo...
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| Format: | Article |
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MDPI AG
2020-04-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/21/8/2719 |
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| author | Céline Koster Kimberley E. Wever Ellie L. Wagstaff Koen T. van den Hurk Carlijn R. Hooijmans Arthur A. Bergen |
| author_facet | Céline Koster Kimberley E. Wever Ellie L. Wagstaff Koen T. van den Hurk Carlijn R. Hooijmans Arthur A. Bergen |
| author_sort | Céline Koster |
| collection | DOAJ |
| description | The retinal pigment epithelium (RPE) and the adjacent light-sensitive photoreceptors form a single functional unit lining the back of the eye. Both cell layers are essential for normal vision. RPE degeneration is usually followed by photoreceptor degeneration and vice versa. There are currently almost no effective therapies available for RPE disorders such as Stargardt disease, specific types of retinitis pigmentosa, and age-related macular degeneration. RPE replacement for these disorders, especially in later stages of the disease, may be one of the most promising future therapies. There is, however, no consensus regarding the optimal RPE source, delivery strategy, or the optimal experimental host in which to test RPE replacement therapy. Multiple RPE sources, delivery methods, and recipient animal models have been investigated, with variable results. So far, a systematic evaluation of the (variables influencing) efficacy of experimental RPE replacement parameters is lacking. Here we investigate the effect of RPE transplantation on vision and vision-based behavior in animal models of retinal degenerated diseases. In addition, we aim to explore the effect of RPE source used for transplantation, the method of intervention, and the animal model which is used. Methods: In this study, we systematically identified all publications concerning transplantation of RPE in experimental animal models targeting the improvement of vision (e.g., outcome measurements related to the morphology or function of the eye). A variety of characteristics, such as species, gender, and age of the animals but also cell type, number of cells, and other intervention characteristics were extracted from all studies. A risk of bias analysis was performed as well. Subsequently, all references describing one of the following outcomes were analyzed in depth in this systematic review: a-, b-, and c-wave amplitudes, vision-based, thickness analyses based on optical coherence tomography (OCT) data, and transplant survival based on scanning laser ophthalmoscopy (SLO) data. Meta-analyses were performed on the a- and b-wave amplitudes from electroretinography (ERG) data as well as data from vision-based behavioral assays. Results: original research articles met the inclusion criteria after two screening rounds. Overall, most studies were categorized as unclear regarding the risk of bias, because many experimental details were poorly reported. Twenty-three studies reporting one or more of the outcome measures of interest were eligible for either descriptive (thickness analyses based on OCT data; <i>n</i> = 2) or meta-analyses. RPE transplantation significantly increased ERG a-wave (Hedges’ g 1.181 (0.471–1.892), <i>n</i> = 6) and b-wave (Hedges’ g 1.734 (1.295–2.172), <i>n</i> = 42) amplitudes and improved vision-based behavior (Hedges’ g 1.018 (0.826–1.209), <i>n</i> = 96). Subgroup analyses revealed a significantly increased effect of the use of young and adolescent animals compared to adult animals. Moreover, transplanting more cells (in the range of 10<sup>5</sup> versus in the range of 10<sup>4</sup>) resulted in a significantly increased effect on vision-based behavior as well. The origin of cells mattered as well. A significantly increased effect was found on vision-based behavior when using ARPE-19 and OpRegen<sup>®</sup> RPE. Conclusions: This systematic review shows that RPE transplantation in animal models for retinal degeneration significantly increases a- and b- wave amplitudes and improves vision-related behavior. These effects appear to be more pronounced in young animals, when the number of transplanted cells is larger and when ARPE-19 and OpRegen<sup>®</sup> RPE cells are used. We further emphasize that there is an urgent need for improving the reporting and methodological quality of animal experiments, to make such studies more comparable. |
| first_indexed | 2024-03-10T20:28:10Z |
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| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T20:28:10Z |
| publishDate | 2020-04-01 |
| publisher | MDPI AG |
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| series | International Journal of Molecular Sciences |
| spelling | doaj.art-7380a6a2b89d40878863d4d85d27b26d2023-11-19T21:37:22ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672020-04-01218271910.3390/ijms21082719A Systematic Review on Transplantation Studies of the Retinal Pigment Epithelium in Animal ModelsCéline Koster0Kimberley E. Wever1Ellie L. Wagstaff2Koen T. van den Hurk3Carlijn R. Hooijmans4Arthur A. Bergen5Department of Clinical Genetics, Amsterdam University Medical Centers (AUMC), location Academic Medical Center (AMC), University of Amsterdam (UvA), 1105 AZ Amsterdam, The NetherlandsSystematic Review Center for Laboratory Animal Experimentation (SYRCLE), Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The NetherlandsDepartment of Clinical Genetics, Amsterdam University Medical Centers (AUMC), location Academic Medical Center (AMC), University of Amsterdam (UvA), 1105 AZ Amsterdam, The NetherlandsDepartment of Clinical Genetics, Amsterdam University Medical Centers (AUMC), location Academic Medical Center (AMC), University of Amsterdam (UvA), 1105 AZ Amsterdam, The NetherlandsSystematic Review Center for Laboratory Animal Experimentation (SYRCLE), Department for Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The NetherlandsDepartment of Clinical Genetics, Amsterdam University Medical Centers (AUMC), location Academic Medical Center (AMC), University of Amsterdam (UvA), 1105 AZ Amsterdam, The NetherlandsThe retinal pigment epithelium (RPE) and the adjacent light-sensitive photoreceptors form a single functional unit lining the back of the eye. Both cell layers are essential for normal vision. RPE degeneration is usually followed by photoreceptor degeneration and vice versa. There are currently almost no effective therapies available for RPE disorders such as Stargardt disease, specific types of retinitis pigmentosa, and age-related macular degeneration. RPE replacement for these disorders, especially in later stages of the disease, may be one of the most promising future therapies. There is, however, no consensus regarding the optimal RPE source, delivery strategy, or the optimal experimental host in which to test RPE replacement therapy. Multiple RPE sources, delivery methods, and recipient animal models have been investigated, with variable results. So far, a systematic evaluation of the (variables influencing) efficacy of experimental RPE replacement parameters is lacking. Here we investigate the effect of RPE transplantation on vision and vision-based behavior in animal models of retinal degenerated diseases. In addition, we aim to explore the effect of RPE source used for transplantation, the method of intervention, and the animal model which is used. Methods: In this study, we systematically identified all publications concerning transplantation of RPE in experimental animal models targeting the improvement of vision (e.g., outcome measurements related to the morphology or function of the eye). A variety of characteristics, such as species, gender, and age of the animals but also cell type, number of cells, and other intervention characteristics were extracted from all studies. A risk of bias analysis was performed as well. Subsequently, all references describing one of the following outcomes were analyzed in depth in this systematic review: a-, b-, and c-wave amplitudes, vision-based, thickness analyses based on optical coherence tomography (OCT) data, and transplant survival based on scanning laser ophthalmoscopy (SLO) data. Meta-analyses were performed on the a- and b-wave amplitudes from electroretinography (ERG) data as well as data from vision-based behavioral assays. Results: original research articles met the inclusion criteria after two screening rounds. Overall, most studies were categorized as unclear regarding the risk of bias, because many experimental details were poorly reported. Twenty-three studies reporting one or more of the outcome measures of interest were eligible for either descriptive (thickness analyses based on OCT data; <i>n</i> = 2) or meta-analyses. RPE transplantation significantly increased ERG a-wave (Hedges’ g 1.181 (0.471–1.892), <i>n</i> = 6) and b-wave (Hedges’ g 1.734 (1.295–2.172), <i>n</i> = 42) amplitudes and improved vision-based behavior (Hedges’ g 1.018 (0.826–1.209), <i>n</i> = 96). Subgroup analyses revealed a significantly increased effect of the use of young and adolescent animals compared to adult animals. Moreover, transplanting more cells (in the range of 10<sup>5</sup> versus in the range of 10<sup>4</sup>) resulted in a significantly increased effect on vision-based behavior as well. The origin of cells mattered as well. A significantly increased effect was found on vision-based behavior when using ARPE-19 and OpRegen<sup>®</sup> RPE. Conclusions: This systematic review shows that RPE transplantation in animal models for retinal degeneration significantly increases a- and b- wave amplitudes and improves vision-related behavior. These effects appear to be more pronounced in young animals, when the number of transplanted cells is larger and when ARPE-19 and OpRegen<sup>®</sup> RPE cells are used. We further emphasize that there is an urgent need for improving the reporting and methodological quality of animal experiments, to make such studies more comparable.https://www.mdpi.com/1422-0067/21/8/2719retinal degenerative diseasesretinal pigment epithelium (RPE)cell therapysystematic reviewmeta-analysistransplantation |
| spellingShingle | Céline Koster Kimberley E. Wever Ellie L. Wagstaff Koen T. van den Hurk Carlijn R. Hooijmans Arthur A. Bergen A Systematic Review on Transplantation Studies of the Retinal Pigment Epithelium in Animal Models International Journal of Molecular Sciences retinal degenerative diseases retinal pigment epithelium (RPE) cell therapy systematic review meta-analysis transplantation |
| title | A Systematic Review on Transplantation Studies of the Retinal Pigment Epithelium in Animal Models |
| title_full | A Systematic Review on Transplantation Studies of the Retinal Pigment Epithelium in Animal Models |
| title_fullStr | A Systematic Review on Transplantation Studies of the Retinal Pigment Epithelium in Animal Models |
| title_full_unstemmed | A Systematic Review on Transplantation Studies of the Retinal Pigment Epithelium in Animal Models |
| title_short | A Systematic Review on Transplantation Studies of the Retinal Pigment Epithelium in Animal Models |
| title_sort | systematic review on transplantation studies of the retinal pigment epithelium in animal models |
| topic | retinal degenerative diseases retinal pigment epithelium (RPE) cell therapy systematic review meta-analysis transplantation |
| url | https://www.mdpi.com/1422-0067/21/8/2719 |
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