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Abstract
The availability of noninvasive high-resolution imaging technology, the immune-suppressive nature of the subretinal space, and the existence of surgical techniques that permit transplantation surgery to be a safe procedure all render the eye an ideal organ in which to begin cell-based therapy in the central nervous system. A number of early stage clinical trials are underway to assess the safety and feasibility of cell-based therapy for retinal blindness. Cell-based therapy using embryonic stem cell-derived differentiated cells (e.g., retinal pigment epithelium (RPE)), neural progenitor cells, photoreceptor precursors, and bone marrow-derived hematopoietic stem/progenitor cells has demonstrated successful rescue and/or replacement in preclinical models of human retinal degenerative disease. Additional research is needed to identify the mechanisms that control synapse formation/disjunction (to improve photoreceptor transplant efficacy), to identify factors that limit RPE survival in areas of geographic atrophy (to improve RPE transplant efficacy in eyes with age-related macular degeneration), and to identify factors that regulate immune surveillance of the subretinal space (to improve long-term photoreceptor and RPE transplant survival).
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Affiliation(s)
- Marco Zarbin
- Institute of Ophthalmology and Visual Science, Rutgers-New Jersey Medical School, Rutgers University, Newark, NJ, USA.
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Qiang S, Alsaeedi HA, Yuhong C, Yang H, Tong L, Kumar S, Higuchi A, Alarfaj AA, Munisvaradass R, Ling MP, Cheng P. Morphological and genetical changes of endothelial progenitor cells after in-vitro conversion into photoreceptors. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2018; 183:127-132. [PMID: 29704860 DOI: 10.1016/j.jphotobiol.2018.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 03/19/2018] [Accepted: 04/03/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND Retinal degeneration is a condition ensued by various ocular disorders such as artery occlusion, diabetic retinopathy, retrolental fibroplasia and retinitis pigmentosa which cause abnormal loss of photoreceptor cells and lead to eventual vision impairment. No efficient treatment has yet been found, however, the use of stem cell therapy such as bone marrow and embryonic stem cells has opened a new treatment modality for retinal degenerative diseases. The major goal of this study is to analyze the potential of endothelial progenitor cells derived from bone marrow to differentiate into retinal neural cells for regenerative medicine purposes. METHODS In this study, endothelial progenitor cells were induced in-vitro with photoreceptor growth factor (taurine) for 21 days. Subsequently, the morphology and gene expression of CRX and RHO of the photoreceptors-induced EPCs were examined through immunostaining assay. FINDINGS The results indicated that the induced endothelial progenitor cells demonstrated positive gene expression of CRX and RHO. Our findings suggested that EPC cells may have a high advantage in cell replacement therapy for treating eye disease, in addition to other neural diseases, and may be a suitable cell source in regenerative medicine for eye disorders.
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Affiliation(s)
- Shi Qiang
- Opthalmology Department, First Affiliated Hospital of Xi'an Jiao Tong University, China
| | - Hiba Amer Alsaeedi
- Department of Medical Microbiology and Parasitology, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia.
| | - Cheng Yuhong
- Opthalmology Department, First Affiliated Hospital of Xi'an Jiao Tong University, China
| | - Hao Yang
- Opthalmology Department, First Affiliated Hospital of Xi'an Jiao Tong University, China
| | - Li Tong
- Opthalmology Department, First Affiliated Hospital of Xi'an Jiao Tong University, China
| | - Suresh Kumar
- Department of Medical Microbiology and Parasitology, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
| | - Akon Higuchi
- Department of Chemical and Materials Engineering, National Central University, Jhong-li, Taoyuan 32001, Taiwan; Department of Botany and Microbiology, King Saud University, Riyadh 11451, Saudi Arabia
| | - Abdullah A Alarfaj
- Department of Botany and Microbiology, King Saud University, Riyadh 11451, Saudi Arabia
| | - Rusheni Munisvaradass
- Department of Clinical Laboratory Sciences, College of Applied Medical Science, Aljouf University, Sakaka, P.O. Box 2014, Aljouf Province, Saudi Arabia
| | - Mok Pooi Ling
- Department of Biomedical Science, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia; Genetics and Regenerative Medicine Research Center, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
| | - Pei Cheng
- Opthalmology Department, First Affiliated Hospital of Xi'an Jiao Tong University, China.
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Cellular regeneration strategies for macular degeneration: past, present and future. Eye (Lond) 2018; 32:946-971. [PMID: 29503449 PMCID: PMC5944658 DOI: 10.1038/s41433-018-0061-z] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/05/2018] [Accepted: 01/15/2018] [Indexed: 01/12/2023] Open
Abstract
Despite considerable effort and significant therapeutic advances, age-related macular degeneration (AMD) remains the commonest cause of blindness in the developed world. Progressive late-stage AMD with outer retinal degeneration currently has no proven treatment. There has been significant interest in the possibility that cellular treatments may slow or reverse visual loss in AMD. A number of modes of action have been suggested, including cell replacement and rescue, as well as immune modulation to delay the neurodegenerative process. Their appeal in this enigmatic disease relate to their generic, non-pathway-specific effects. The outer retina in particular has been at the forefront of developments in cellular regenerative therapies being surgically accessible, easily observable, as well as having a relatively simple architecture. Both the retinal pigment epithelium (RPE) and photoreceptors have been considered for replacement therapies as both sheets and cell suspensions. Studies using autologous RPE, and to a lesser extent, foetal retina, have shown proof of principle. A wide variety of cell sources have been proposed with pluripotent stem cell-derived cells currently holding the centre stage. Recent early-phase trials using these cells for RPE replacement have met safety endpoints and hinted at possible efficacy. Animal studies have confirmed the promise that photoreceptor replacement, even in a completely degenerated outer retina may restore some vision. Many challenges, however, remain, not least of which include avoiding immune rejection, ensuring long-term cellular survival and maximising effect. This review provides an overview of progress made, ongoing studies and challenges ahead.
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Antibiotics Reduce Retinal Cell Survival In Vitro. Neurotox Res 2017; 33:781-789. [PMID: 29098663 DOI: 10.1007/s12640-017-9826-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 09/24/2017] [Accepted: 10/05/2017] [Indexed: 10/18/2022]
Abstract
Antibiotics such as gentamicin (an aminoglycoside) and penicillin (a beta-lactam antibiotic) are routinely used in retinal cell and explant cultures. In many cases, these in vitro systems are testing parameters regarding photoreceptor transplantation or preparing cells for transplantation. In vivo, milligram doses of gentamicin are neurotoxic to the retina. However, little is known about the effects of antibiotics to retina in vitro and whether smaller doses of gentamicin are toxic to retinal cells. To test toxicity, retinal cells were dissociated from tiger salamander, placed in culture, and treated with either 20 μg/ml gentamicin, 100 μg/ml streptomycin, 100 U/ml antibiotic/antimycotic, 0.25 μg/ml amphotericin B, or 100 U/ml penicillin G. All dosages were within manufacturer's recommended levels. Control cultures had defined medium only. Cells were fixed at 2 h or 7 days. Three criteria were used to assess toxicity: (1) survival of retinal neurons, (2) neuritic growth of photoreceptors assessed by the development of presynaptic varicosities, and (3) survival and morphology of Mueller cells. Rod cells were immunolabeled for rod opsin, Mueller cells for glial fibrillary acidic protein, and varicosities for synaptophysin. Neuronal cell density was reduced with all pharmacological treatments. The number of presynaptic varicosities was also significantly lower in both rod and cone photoreceptors in treated compared to control cultures; further, rods were more sensitive to gentamicin than cones. Penicillin G (100 U/ml) was overall the least inhibitory and amphotericin B the most toxic of all the agents to photoreceptors. Mueller cell survival was reduced with all treatments; reduced survival was accompanied by the appearance of proportionally fewer stellate and more rounded glial morphologies. These findings suggest that even microgram doses of antibiotic and antimycotic drugs can be neurotoxic to retinal cells and reduce neuritic regeneration in cell culture systems.
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Zarbin M. Cell-Based Therapy for Degenerative Retinal Disease. Trends Mol Med 2016; 22:115-134. [PMID: 26791247 DOI: 10.1016/j.molmed.2015.12.007] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Revised: 12/16/2015] [Accepted: 12/17/2015] [Indexed: 12/21/2022]
Abstract
Stem cell-derived retinal pigment epithelium (RPE) and photoreceptors (PRs) have restored vision in preclinical models of human retinal degenerative disease. This review discusses characteristics of stem cell therapy in the eye and the challenges to clinical implementation that are being confronted today. Based on encouraging results from Phase I/II trials, the first Phase II clinical trials of stem cell-derived RPE transplantation are underway. PR transplant experiments have demonstrated restoration of visual function in preclinical models of retinitis pigmentosa and macular degeneration, but also indicate that no single approach is likely to succeed in overcoming PR loss in all cases. A greater understanding of the mechanisms controlling synapse formation as well as the immunoreactivity of transplanted retinal cells is urgently needed.
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Affiliation(s)
- Marco Zarbin
- Rutgers New Jersey Medical School, Newark, NJ 07103, USA.
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Stanzel BV, Liu Z, Somboonthanakij S, Wongsawad W, Brinken R, Eter N, Corneo B, Holz FG, Temple S, Stern JH, Blenkinsop TA. Human RPE stem cells grown into polarized RPE monolayers on a polyester matrix are maintained after grafting into rabbit subretinal space. Stem Cell Reports 2014; 2:64-77. [PMID: 24511471 PMCID: PMC3916756 DOI: 10.1016/j.stemcr.2013.11.005] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 11/07/2013] [Accepted: 11/08/2013] [Indexed: 12/22/2022] Open
Abstract
Transplantation of the retinal pigment epithelium (RPE) is being developed as a cell-replacement therapy for age-related macular degeneration. Human embryonic stem cell (hESC) and induced pluripotent stem cell (iPSC)-derived RPE are currently translating toward clinic. We introduce the adult human RPE stem cell (hRPESC) as an alternative RPE source. Polarized monolayers of adult hRPESC-derived RPE grown on polyester (PET) membranes had near-native characteristics. Trephined pieces of RPE monolayers on PET were transplanted subretinally in the rabbit, a large-eyed animal model. After 4 days, retinal edema was observed above the implant, detected by spectral domain optical coherence tomography (SD-OCT) and fundoscopy. At 1 week, retinal atrophy overlying the fetal or adult transplant was observed, remaining stable thereafter. Histology obtained 4 weeks after implantation confirmed a continuous polarized human RPE monolayer on PET. Taken together, the xeno-RPE survived with retained characteristics in the subretinal space. These experiments support that adult hRPESC-derived RPE are a potential source for transplantation therapies. Adult hRPESC-derived RPE had comparable in vitro characteristics to fetal hRPE hRPE monolayers survived 4 weeks on PET carriers under the rabbit retina Better xenograft survival may be due to the maintained hRPE cell polarity Atrophy of the retina overlaying the hRPE xenograft remains a future challenge
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Affiliation(s)
- Boris V Stanzel
- Department of Ophthalmology, University of Bonn, Bonn 53127, Germany
| | - Zengping Liu
- Department of Ophthalmology, University of Bonn, Bonn 53127, Germany
| | - Sudawadee Somboonthanakij
- Department of Ophthalmology, University of Bonn, Bonn 53127, Germany ; Mettapracharak Eye Institute, Raikhing, Nakhon Pathom 73210, Thailand
| | - Warapat Wongsawad
- Department of Ophthalmology, University of Bonn, Bonn 53127, Germany ; Mettapracharak Eye Institute, Raikhing, Nakhon Pathom 73210, Thailand
| | - Ralf Brinken
- Department of Ophthalmology, University of Bonn, Bonn 53127, Germany
| | - Nicole Eter
- Department of Ophthalmology, University of Muenster, Muenster 48149, Germany
| | | | - Frank G Holz
- Department of Ophthalmology, University of Bonn, Bonn 53127, Germany
| | - Sally Temple
- Neural Stem Cell Institute, Rensselaer, NY 12144, USA
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Hsu WM, Chen KH, Lai JY, Hsiue GH. Transplantation of Human Corneal Endothelial Cells Using Functional Biomaterials: Poly(N-isopropylacrylamide) and Gelatin. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.jecm.2013.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Seiler MJ, Aramant RB. Cell replacement and visual restoration by retinal sheet transplants. Prog Retin Eye Res 2012; 31:661-87. [PMID: 22771454 PMCID: PMC3472113 DOI: 10.1016/j.preteyeres.2012.06.003] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 06/19/2012] [Accepted: 06/23/2012] [Indexed: 12/18/2022]
Abstract
Retinal diseases such as age-related macular degeneration (ARMD) and retinitis pigmentosa (RP) affect millions of people. Replacing lost cells with new cells that connect with the still functional part of the host retina might repair a degenerating retina and restore eyesight to an unknown extent. A unique model, subretinal transplantation of freshly dissected sheets of fetal-derived retinal progenitor cells, combined with its retinal pigment epithelium (RPE), has demonstrated successful results in both animals and humans. Most other approaches are restricted to rescue endogenous retinal cells of the recipient in earlier disease stages by a 'nursing' role of the implanted cells and are not aimed at neural retinal cell replacement. Sheet transplants restore lost visual responses in several retinal degeneration models in the superior colliculus (SC) corresponding to the location of the transplant in the retina. They do not simply preserve visual performance - they increase visual responsiveness to light. Restoration of visual responses in the SC can be directly traced to neural cells in the transplant, demonstrating that synaptic connections between transplant and host contribute to the visual improvement. Transplant processes invade the inner plexiform layer of the host retina and form synapses with presumable host cells. In a Phase II trial of RP and ARMD patients, transplants of retina together with its RPE improved visual acuity. In summary, retinal progenitor sheet transplantation provides an excellent model to answer questions about how to repair and restore function of a degenerating retina. Supply of fetal donor tissue will always be limited but the model can set a standard and provide an informative base for optimal cell replacement therapies such as embryonic stem cell (ESC)-derived therapy.
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Affiliation(s)
- Magdalene J Seiler
- Department of Anatomy & Neurobiology, Reeve-Irvine Research Center, Sue & Bill Gross Stem Cell Research Center, University of California at Irvine, 1101 Gross Hall, 845 Health Science Rd., Irvine, CA 92697-4265, USA.
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Rowland TJ, Buchholz DE, Clegg DO. Pluripotent human stem cells for the treatment of retinal disease. J Cell Physiol 2012; 227:457-66. [PMID: 21520078 DOI: 10.1002/jcp.22814] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Despite advancements made in our understanding of ocular biology, therapeutic options for many debilitating retinal diseases remain limited. Stem cell-based therapies are a potential avenue for treatment of retinal disease, and this mini-review will focus on current research in this area. Cellular therapies to replace retinal pigmented epithelium (RPE) and/or photoreceptors to treat age-related macular degeneration (AMD), Stargardt's macular dystrophy, and retinitis pigmentosa are currently being developed. Over the past decade, significant advancements have been made using different types of human stem cells with varying capacities to differentiate into these target retinal cell types. We review and evaluate pluripotent stem cells, both human embryonic stem cells and human induced pluripotent stem cells, as well as protocols for differentiation of ocular cells, and culture and transplant techniques that might be used to deliver cells to patients.
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Affiliation(s)
- Teisha J Rowland
- Center for Stem Cell Biology and Engineering, University of California, Santa Barbara, California, USA
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Lai JY, Li YT. Evaluation of cross-linked gelatin membranes as delivery carriers for retinal sheets. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2010. [DOI: 10.1016/j.msec.2010.02.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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A tissue-engineered approach towards retinal repair: scaffolds for cell transplantation to the subretinal space. Graefes Arch Clin Exp Ophthalmol 2010; 248:763-78. [PMID: 20169358 DOI: 10.1007/s00417-009-1263-7] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2009] [Revised: 11/16/2009] [Accepted: 11/26/2009] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Several mechanisms of retina degeneration result in the deterioration of the outer retina and can lead to blindness. Currently, with the exception of anti-angiogenic treatments for wet age-related macular degeneration, there are no treatments that can restore lost vision. There is evidence that photoreceptors and embryonic retinal tissue, transplanted to the subretinal space, can form new synapses with surviving host neurons. However, these transplants have yet to result in a clinical treatment for retinal degeneration. METHODS This article reviews the current literature on the transplantation of scaffolds with retinal and retinal pigmented epithelial (RPE) cells to the subretinal space. We discuss the types of cells and materials that have been investigated for transplantation to the subretinal space, summarize the current findings, and present opportunities for future research and the next generation of scaffolds for retinal repair. RESULTS Challenges to cell transplantation include limited survival upon implantation and the formation of abnormal cell architectures in vivo. Scaffolds have been shown to enhance cell survival and direct cell differentiation and organization in a number of models of retinal degeneration. CONCLUSIONS The transplantation of cells within a scaffold represents a possible treatment to repair retinal degeneration and restore vision in effected patients. Materials have been developed for the delivery of retinal and RPE cells separately however, the development of a combined tissue-engineered scaffold targeting both cell populations represents a promising direction for retinal repair.
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Lai JY, Lin PK, Hsiue GH, Cheng HY, Huang SJ, Li YT. Low Bloom Strength Gelatin as a Carrier for Potential Use in Retinal Sheet Encapsulation and Transplantation. Biomacromolecules 2008; 10:310-9. [DOI: 10.1021/bm801039n] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jui-Yang Lai
- Institute of Biochemical and Biomedical Engineering, Biomedical Engineering Research Center, and Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan 33302, Republic of China, Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan 11217, Republic of China, and Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan 30013, Republic of China
| | - Po-Kang Lin
- Institute of Biochemical and Biomedical Engineering, Biomedical Engineering Research Center, and Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan 33302, Republic of China, Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan 11217, Republic of China, and Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan 30013, Republic of China
| | - Ging-Ho Hsiue
- Institute of Biochemical and Biomedical Engineering, Biomedical Engineering Research Center, and Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan 33302, Republic of China, Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan 11217, Republic of China, and Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan 30013, Republic of China
| | - Hsiao-Yun Cheng
- Institute of Biochemical and Biomedical Engineering, Biomedical Engineering Research Center, and Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan 33302, Republic of China, Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan 11217, Republic of China, and Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan 30013, Republic of China
| | - Shu-Jung Huang
- Institute of Biochemical and Biomedical Engineering, Biomedical Engineering Research Center, and Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan 33302, Republic of China, Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan 11217, Republic of China, and Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan 30013, Republic of China
| | - Ya-Ting Li
- Institute of Biochemical and Biomedical Engineering, Biomedical Engineering Research Center, and Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan 33302, Republic of China, Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan 11217, Republic of China, and Department of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan 30013, Republic of China
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Tissue-Engineered Human Corneal Endothelial Cell Sheet Transplantation in a Rabbit Model Using Functional Biomaterials. Transplantation 2007; 84:1222-32. [DOI: 10.1097/01.tp.0000287336.09848.39] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Retinal Pigment Epithelium and Photoreceptor Transplantation Frontiers. Retina 2006. [DOI: 10.1016/b978-0-323-02598-0.50159-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Aramant RB, Seiler MJ. Transplanted sheets of human retina and retinal pigment epithelium develop normally in nude rats. Exp Eye Res 2002; 75:115-25. [PMID: 12137757 DOI: 10.1006/exer.2002.2001] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study investigated whether transplanted sheets of human fetal retina together with its retinal pigment epithelium (RPE) could develop and maintain their cytoarchitecture after long survival times. Transplant recipients were nine albino athymic nu/nu rats with a normal retina. The donor tissue was dissected from fetuses of 12-17 weeks gestational age. Transplants were analyzed at 5-12 months after surgery by light and electron microscopy, and immunohistochemistry with various antibodies specific for rhodopsin, S-antigen, transducin, neurofilament and synaptophysin. In 4 of 11 transplants, the RPE stayed as a monolayer sheet and supported the development of the retinal sheet with a normal lamination, including photoreceptor inner and outer segments. Cones and rods in the organized transplants were labeled with different photoreceptor markers. Inner and outer plexiform layers, containing cone pedicles and rods spherules, were immunoreactive for synaptophysin. As the recipients had a normal retina, transplant/host integration was not expected. However, at the transplant/host interface, there were sometimes areas without glial barriers, and neurofilament-containing processes could be observed crossing between transplant and host. In other, more disorganized transplants, the RPE cells were partially dispersed or clumped together in clusters. Such transplants developed photoreceptors in rosettes, often with inner and outer segments. In conclusion, sheets of human fetal retina transplanted together with its RPE to the subretinal space of nude rats can develop and maintain perfectly laminated transplants after long survival times, indicating the potential of applying cotransplantation to human patients with retinal diseases.
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Affiliation(s)
- Robert B Aramant
- Departments of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY 40202, USA.
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Abstract
Retinal transplantation aims to prevent blindness and to restore eyesight, i.e., to rescue photoreceptors or to replace damaged photoreceptors with the hope of reestablishing neural circuitry. Retinal donor tissue has been transplanted as dissociated cells or intact sheets. A promising experimental paradigm is the subretinal transplantation of sheets of fetal retina with or without its attached retinal pigment epithelium (RPE) into recipient rats with retinal degeneration. As long as healthy RPE either from the host or from the graft is present, such transplants can develop lamination resembling a normal retina. Different methods have been used to demonstrate transplant/host connectivity. In two different rat retinal degeneration models, visually evoked responses can be demonstrated in an area of the superior colliculus corresponding to the placement of the transplant in the retina. In summary, sheets of fetal retina can morphologically repair an area of a degenerated retina, and there is evidence to suggest that transplants form synaptic connections with the host and restore visual responses in blind rats.
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Affiliation(s)
- Robert B Aramant
- Department of Ophthalmology and Visual Sciences, University of Louisville, School of Medicine, 301 E. Muhammad Ali Blvd., KY 40202, USA.
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Kicic A, Shen W, Rakoczy PE. The potential of marrow stromal cells in stem cell therapy. Eye (Lond) 2001; 15:695-707. [PMID: 11826986 DOI: 10.1038/eye.2001.233] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- A Kicic
- Stem Cell Unit, Lions Eye Institute, Nedlands, Western Australia, Australia
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Lund RD, Kwan AS, Keegan DJ, Sauvé Y, Coffey PJ, Lawrence JM. Cell transplantation as a treatment for retinal disease. Prog Retin Eye Res 2001; 20:415-49. [PMID: 11390255 DOI: 10.1016/s1350-9462(01)00003-9] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It has been shown that photoreceptor degeneration can be limited in experimental animals by transplantation of fresh RPE to the subretinal space. There is also evidence that retinal cell transplants can be used to reconstruct retinal circuitry in dystrophic animals. Here we describe and review recent developments that highlight the necessary steps that should be taken prior to embarking on clinical trials in humans.
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Affiliation(s)
- R D Lund
- Institute of Ophthalmology, Bath Street, EC1V 9EL, London, UK
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Coffey PJ, Whiteley SJ, Lund RD. Preservation and restoration of vision following transplantation. PROGRESS IN BRAIN RESEARCH 2001; 127:489-99. [PMID: 11142043 DOI: 10.1016/s0079-6123(00)27024-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Affiliation(s)
- P J Coffey
- Visual Transplantation Research Group, Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TP, UK.
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Abstract
PURPOSE To describe a method for isolating a monolayer of human fetal cone photoreceptors and to compare their structure and ultrastructure before and after preparation. METHODS Eyes from human fetuses (fetal week 20 to 24) were dissected and the neural retina of the developing fovea identified, cut out and placed on 10% gelatin. A VISX Star excimer laser was used to remove the inner retinal layers. The isolated cone monolayers were cultured for 18 hours and compared with untreated retinas by light microscopy and transmission electron microscopy. RESULTS Excimer laser ablation removed the inner nuclear and ganglion cell layers leaving a monolayer of fetal cones. These cones survive in culture for at least 18 hours. The laser ablation disorganized the ultrastructure of the synaptic pedicles of these cones, left their plasma membranes intact. CONCLUSIONS The developing central retina of human fetal eyes provides a source of fetal cones, which can be isolated from inner retinal cells using the excimer laser. Such a monolayer of human fetal cones may be useful for transplantation or biochemical studies.
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Affiliation(s)
- D J Salchow
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University, New York, New York 10032, USA.
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Kwan AS, Wang S, Lund RD. Photoreceptor layer reconstruction in a rodent model of retinal degeneration. Exp Neurol 1999; 159:21-33. [PMID: 10486172 DOI: 10.1006/exnr.1999.7157] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We have examined the potential of retinal cell transplantation to dystrophic retinal degeneration mice as a way of replacing photoreceptors lost because of an intrinsic genetic defect. Early postnatal retinae which had been gently dissociated survived for at least 6 weeks after transplantation to the subretinal space. Over a significant area of distribution, transplanted cells formed outer segments which lay in close apposition to the host retinal pigment epithelial cell layer. The grafts integrated with the remaining host retina, sufficient at least to mediate a simple light-dark preference. A new synaptic layer was seen at the graft-host interface, which contained substantial numbers of photoreceptor synapses. This and the fact that the behavior could be elicited at low luminance levels argue for functional circuit reconstruction between grafted cells and host retina.
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MESH Headings
- 3',5'-Cyclic-GMP Phosphodiesterases/genetics
- 3',5'-Cyclic-GMP Phosphodiesterases/metabolism
- Animals
- Behavior, Animal
- Cyclic Nucleotide Phosphodiesterases, Type 6
- Darkness
- Disease Models, Animal
- Genes, Recessive
- Graft Survival
- Lighting
- Mice
- Mice, Congenic
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Microscopy, Electron
- Mutation
- Phosphoric Diester Hydrolases
- Retina/surgery
- Retinal Rod Photoreceptor Cells/enzymology
- Retinal Rod Photoreceptor Cells/transplantation
- Retinal Rod Photoreceptor Cells/ultrastructure
- Retinitis Pigmentosa/genetics
- Retinitis Pigmentosa/therapy
- Vision, Ocular
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Affiliation(s)
- A S Kwan
- Neural Transplant Program Department of Pathology, Institute of Ophthalmology, University College London, Bath Street, London, EC1V 9EL, United Kingdom
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Excimerlaserablation fetaler Netzhaut für die retinale Transplantation. SPEKTRUM DER AUGENHEILKUNDE 1999. [DOI: 10.1007/bf03163026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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