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TRANSPLANTATION OF SUBRETINAL STEM CELL-DERIVED RETINAL PIGMENT EPITHELIUM FOR STARGARDT DISEASE: A Phase I Clinical Trial. Retina 2023; 43:263-274. [PMID: 36223778 DOI: 10.1097/iae.0000000000003655] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
PURPOSE To assess the safety of injecting human embryonic stem cell retinal pigment epithelial cell dose to treat Stargardt disease. METHODS In this prospective, Phase I clinical trial, human embryonic stem cell retinal pigment epithelial cells in suspension were injected into the subretinal space in eyes with the worse best-corrected visual acuity (BCVA). After vitrectomy/posterior hyaloid removal, a partial retinal detachment was created and the human embryonic stem cell retinal pigment epithelial cells were administered. Phacoemulsification with intraocular lens implantation was performed in eyes with lens opacity. All procedures were optical coherence tomography-guided. The 12-month follow-up included retinal imaging, optical coherence tomography, visual field/electrophysiologic testing, and systemic evaluation. The main outcome was the absence of ocular/systemic inflammation or rejection, tumor formation, or toxicity during follow-up. RESULTS The mean baseline BCVAs in the phacoemulsification and no phacoemulsification groups were similar (1.950 ± 0.446 and 1.575 ± 0.303, respectively). One year postoperatively, treated eyes showed a nonsignificant increase in BCVA. No adverse effects occurred during follow-up. Intraoperative optical coherence tomography was important for guiding all procedures. CONCLUSION This surgical procedure was feasible and safe without cellular migration, rejection, inflammation, or development of ocular or systemic tumors during follow-up.
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McCormick R, Pearce I, Kaye S, Haneef A. Optimisation of a Novel Bio-Substrate as a Treatment for Atrophic Age-Related Macular Degeneration. Front Bioeng Biotechnol 2020; 8:456. [PMID: 32500067 PMCID: PMC7243032 DOI: 10.3389/fbioe.2020.00456] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 04/21/2020] [Indexed: 01/13/2023] Open
Abstract
Atrophic age-related macular degeneration (AMD) is the most common form of AMD accounting for 90% of patients. During atrophic AMD the waste/exchange pathway between the blood supply (choroid) and the retinal pigment epithelium (RPE) is compromised. This results in atrophy and death of the RPE cells and subsequently the photoreceptors leading to central blindness. Although the mechanisms behind AMD are unknown, the growth of fatty deposits known as drusen, have been shown to play a role in the disease. There is currently no treatment or cure for atrophic AMD. Much research focuses on developing a synthetic substrate in order to transplant healthy cells to the native Bruch’s membrane (BM), however, the diseased native BM and related structures still leave potential for transplanted cells to succumb to disease. In this proof-of-concept work we electrospun poly(ethylene terephthalate) (PET) to fabricate a nanofibrous cytocompatible synthetic BM. The apical surface of the membrane was cultured with ARPE-19 cells and the underside was decorated with poly(lactic acid-co-glycolic acid) (PLGA) or poly(glycolic acid) (PGA) degradable nanoparticles by electrospraying. The membrane exhibited hydrophilicity, high tensile strength and structurally resembled the native BM. ARPE-19 cells were able to form a monolayer on the surface of the membrane and no cell invasion into the membrane was seen. The presence of both PLGA and PGA nanoparticles increased ARPE-19 cell metabolism but had no effect on cell viability. There was a decrease in pH of ARPE-19 cell culture media 7 days following culturing with the PLGA nanoparticles but this change was eliminated by 2 weeks; PGA nanoparticles had no effect on cell culture media pH. The fluorescent dye FITC was encapsulated into nanoparticles and showed sustained release from PLGA nanoparticles for 2 weeks and PGA nanoparticles for 1 day. Future work will focus on encapsulating biologically active moieties to target drusen. This could allow this novel bioactive substrate to be a potential treatment for atrophic AMD that would function two-fold: deliver the required monolayer of healthy RPE cells to the macula on a synthetic BM and remove diseased structures within the retina, restoring the waste/exchange pathway and preventing vision loss.
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Affiliation(s)
- Rachel McCormick
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Ian Pearce
- St Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom
| | - Stephen Kaye
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom.,St Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom
| | - Atikah Haneef
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
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3
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On the origin of proteins in human drusen: The meet, greet and stick hypothesis. Prog Retin Eye Res 2018; 70:55-84. [PMID: 30572124 DOI: 10.1016/j.preteyeres.2018.12.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 12/12/2022]
Abstract
Retinal drusen formation is not only a clinical hallmark for the development of age-related macular degeneration (AMD) but also for other disorders, such as Alzheimer's disease and renal diseases. The initiation and growth of drusen is poorly understood. Attention has focused on lipids and minerals, but relatively little is known about the origin of drusen-associated proteins and how they are retained in the space between the basal lamina of the retinal pigment epithelium and the inner collagenous layer space (sub-RPE-BL space). While some authors suggested that drusen proteins are mainly derived from cellular debris from processed photoreceptor outer segments and the RPE, others suggest a choroidal cell or blood origin. Here, we reviewed and supplemented the existing literature on the molecular composition of the retina/choroid complex, to gain a more complete understanding of the sources of proteins in drusen. These "drusenomics" studies showed that a considerable proportion of currently identified drusen proteins is uniquely originating from the blood. A smaller, but still large fraction of drusen proteins comes from both blood and/or RPE. Only a small proportion of drusen proteins is uniquely derived from the photoreceptors or choroid. We next evaluated how drusen components may "meet, greet and stick" to each other and/or to structures like hydroxyapatite spherules to form macroscopic deposits in the sub-RPE-BL space. Finally, we discuss implications of our findings with respect to the previously proposed homology between drusenogenesis in AMD and plaque formation in atherosclerosis.
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Cui C, Lu H. Clinical observations on the use of new anti-VEGF drug, conbercept, in age-related macular degeneration therapy: a meta-analysis. Clin Interv Aging 2017; 13:51-62. [PMID: 29343949 PMCID: PMC5747960 DOI: 10.2147/cia.s151225] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
PURPOSE Conbercept is a new anti-vascular endothelial growth factor (VEGF) drug approved for the treatment of age-related macular degeneration (AMD). Although this novel drug has been widely used in clinic, unlike other anti-VEGF drugs, validation and consensus on its method of clinical application and clinical safety have not yet been achieved. METHODS Relevant literature was searched on PubMed, Web of Science, China National Knowledge Internet, and Wanfang Data. Stata 12.0 was used for data analysis. Random- and fixed-effect models were employed to evaluate heterogeneity. Best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were utilized to measure the improvement of AMD patients. RESULTS In this study, we analyzed conbercept administration and compared its application with other control clinical methods for AMD treatment. Ranibizumab, triamcinolone, and traditional transpupillary thermotherapy (TTT) were administered in the control group. No differences were found in the BCVA and CRT improvement between the groups treated with conbercept and ranibizumab. However, the conbercept group had a lower serum VEGF level. After 3 months of treatment, conbercept led to a more significant BCVA and CRT improvement than triamcinolone. A more considerable BCVA improvement was observed in the group treated with conbercept than in the group treated with TTT. Moreover, even 6 months after the treatment, the effect of conbercept on CRT improvement was still more pronounced than that of TTT. CONCLUSION In AMD patients, conbercept exerts considerably more positive effects on the long-term BCVA and CRT improvement than triamcinolone and TTT. The serum VEGF level in the conbercept group was lower than that in the ranibizumab group.
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Affiliation(s)
- Chunmei Cui
- Department of Ophthalmology, Beijing Chao-Yang Hospital, Beijing, China
| | - Hong Lu
- Department of Ophthalmology, Beijing Chao-Yang Hospital, Beijing, China
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5
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Fernandes RAB, Stefanini FR, Falabella P, Koss MJ, Wells T, Diniz B, Ribeiro R, Schor P, Maia M, Penha FM, Hinton DR, Tai YC, Humayun M. Development of a new tissue injector for subretinal transplantation of human embryonic stem cell derived retinal pigmented epithelium. Int J Retina Vitreous 2017; 3:41. [PMID: 29093829 PMCID: PMC5662097 DOI: 10.1186/s40942-017-0095-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 09/26/2017] [Indexed: 11/23/2022] Open
Abstract
Background
Subretinal cell transplantation is a challenging surgical maneuver. This paper describes the preliminary findings of a new tissue injector for subretinal implantation of an ultrathin non-absorbable substrate seeded with human embryonic stem cell-derived retinal pigment epithelium (hESC-RPE). Methods Ultrathin Parylene-C substrates measuring 3.5 mm × 6.0 mm seeded with hESC-RPE (implant referred to as CPCB-RPE1) were implanted into the subretinal space of 12 Yucatan minipigs. Animals were euthanized immediately after the procedure and underwent spectral domain optical coherence tomography (SD-OCT) and histological analysis to assess the subretinal placement of the implant. Evaluation of the hESC-RPE cells seeded on the substrate was carried out before and after implantation using standard cell counting techniques. Results The tissue injector delivered the CPCB-RPE1 implant through a 1.5 mm sclerotomy and a 1.0–1.5 mm retinectomy. SD-OCT scans and histological examination revealed that substrates were precisely placed in the subretinal space, and that the hESC-RPE cell monolayer continued to cover the surface of the substrate after the surgical procedure. Conclusion This innovative tissue injector was able to efficiently deliver the implant in the subretinal space of Yucatan minipigs, preventing significant hESC-RPE cell loss, minimizing tissue trauma, surgical complications and postoperative inflammation.
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Affiliation(s)
- Rodrigo A Brant Fernandes
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA USA.,Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Rua Botucatu, 822, São Paulo, SP 04023-062 Brazil
| | - Francisco R Stefanini
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA USA.,Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Rua Botucatu, 822, São Paulo, SP 04023-062 Brazil
| | - Paulo Falabella
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA USA.,Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Rua Botucatu, 822, São Paulo, SP 04023-062 Brazil
| | - Michael J Koss
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA USA.,Augenzentrum Nymphenburger Hoefe, Herzog Carl Theodor Augenklinik, Munich, Germany
| | - Trent Wells
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Bruno Diniz
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA USA.,Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Rua Botucatu, 822, São Paulo, SP 04023-062 Brazil
| | - Ramiro Ribeiro
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA USA.,Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Rua Botucatu, 822, São Paulo, SP 04023-062 Brazil
| | - Paulo Schor
- Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Rua Botucatu, 822, São Paulo, SP 04023-062 Brazil
| | - Mauricio Maia
- Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Rua Botucatu, 822, São Paulo, SP 04023-062 Brazil
| | - Fernando M Penha
- Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Rua Botucatu, 822, São Paulo, SP 04023-062 Brazil.,Fundação Universidade Regional de Blumenau, Blumenau, Santa Catarina Brazil
| | - David R Hinton
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA USA.,Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - Yu-Chong Tai
- Electrical Engineering, California Institute of Technology, Pasadena, CA USA
| | - Mark Humayun
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA USA.,USC Institute for Biomedical Therapeutics, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
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Al-Nawaiseh S, Thieltges F, Liu Z, Strack C, Brinken R, Braun N, Wolschendorf M, Maminishkis A, Eter N, Stanzel BV. A Step by Step Protocol for Subretinal Surgery in Rabbits. J Vis Exp 2016. [PMID: 27684952 PMCID: PMC5092014 DOI: 10.3791/53927] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Age related macular degeneration (AMD), retinitis pigmentosa, and other RPE related diseases are the most common causes for irreversible loss of vision in adults in industrially developed countries. RPE transplantation appears to be a promising therapy, as it may replace dysfunctional RPE, restore its function, and thereby vision. Here we describe a method for transplanting a cultured RPE monolayer on a scaffold into the subretinal space (SRS) of rabbits. After vitrectomy xenotransplants were delivered into the SRS using a custom made shooter consisting of a 20-gauge metallic nozzle with a polytetrafluoroethylene (PTFE) coated plunger. The current technique evolved in over 150 rabbit surgeries over 6 years. Post-operative follow-up can be obtained using non-invasive and repetitive in vivo imaging such as spectral domain optical coherence tomography (SD-OCT) followed by perfusion-fixed histology. The method has well-defined steps for easy learning and high success rate. Rabbits are considered a large eye animal model useful in preclinical studies for clinical translation. In this context rabbits are a cost-efficient and perhaps convenient alternative to other large eye animal models.
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Affiliation(s)
| | | | - Zengping Liu
- Department of Ophthalmology, University of Bonn; Department of Ophthalmology, National University of Singapore
| | | | | | | | | | - Arvydas Maminishkis
- Section on Epithelial and Retinal Physiology and Disease, National Eye Institute/National Institutes of Health
| | - Nicole Eter
- Department of Ophthalmology, University of Münster
| | - Boris V Stanzel
- Department of Ophthalmology, University of Bonn; Surgical Retina Department, Singapore National Eye Centre;
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Heller JP, Kwok JCF, Vecino E, Martin KR, Fawcett JW. A Method for the Isolation and Culture of Adult Rat Retinal Pigment Epithelial (RPE) Cells to Study Retinal Diseases. Front Cell Neurosci 2015; 9:449. [PMID: 26635529 PMCID: PMC4654064 DOI: 10.3389/fncel.2015.00449] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/02/2015] [Indexed: 12/22/2022] Open
Abstract
Diseases such as age-related macular degeneration (AMD) affect the retinal pigment epithelium (RPE) and lead to the death of the epithelial cells and ultimately blindness. RPE transplantation is currently a major focus of eye research and clinical trials using human stem cell-derived RPE cells are ongoing. However, it remains to be established to which extent the source of RPE cells for transplantation affects their therapeutic efficacy and this needs to be explored in animal models. Autotransplantation of RPE cells has attractions as a therapy, but existing protocols to isolate adult RPE cells from rodents are technically difficult, time-consuming, have a low yield and are not optimized for long-term cell culturing. Here, we report a newly devised protocol which facilitates reliable and simple isolation and culture of RPE cells from adult rats. Incubation of a whole rat eyeball in 20 U/ml papain solution for 50 min yielded 4 × 10(4) viable RPE cells. These cells were hexagonal and pigmented upon culture. Using immunostaining, we demonstrated that the cells expressed RPE cell-specific marker proteins including cytokeratin 18 and RPE65, similar to RPE cells in vivo. Additionally, the cells were able to produce and secrete Bruch's membrane matrix components similar to in vivo situation. Similarly, the cultured RPE cells adhered to isolated Bruch's membrane as has previously been reported. Therefore, the protocol described in this article provides an efficient method for the rapid and easy isolation of high quantities of adult rat RPE cells. This provides a reliable platform for studying the therapeutic targets, testing the effects of drugs in a preclinical setup and to perform in vitro and in vivo transplantation experiments to study retinal diseases.
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Affiliation(s)
- Janosch P. Heller
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of CambridgeCambridge, UK
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College LondonLondon, UK
| | - Jessica C. F. Kwok
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of CambridgeCambridge, UK
| | - Elena Vecino
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of CambridgeCambridge, UK
- Department of Cellular Biology, University of the Basque CountryLeioa, UPV/EHU, Bizkaia, Spain
| | - Keith R. Martin
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of CambridgeCambridge, UK
- Department of Ophthalmology, NIHR Biomedical Research Centre and Wellcome Trust—Medical Research Council Cambridge Stem Cell Institute, University of CambridgeCambridge, UK
| | - James W. Fawcett
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of CambridgeCambridge, UK
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8
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Moreira EF, Cai H, Tezel TH, Fields MA, Del Priore LV. Reengineering Human Bruch's Membrane Increases Rod Outer Segment Phagocytosis by Human Retinal Pigment Epithelium. Transl Vis Sci Technol 2015; 4:10. [PMID: 26557417 DOI: 10.1167/tvst.4.5.10] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 08/14/2015] [Indexed: 12/21/2022] Open
Abstract
PURPOSE We have shown previously that Bruch's membrane (BM) aging decreases retinal pigment epithelium (RPE) phagocytosis. Herein, we determine the effects of BM reengineering on RPE phagocytosis. METHODS BM explants were dissected from young and old donor eyes. Some old BM explants were reengineered by cleaning with Triton X-100 and/or coating with extracellular matrix (ECM) ligands. ARPE-19 cell-derived ECM (ARPE-ECM) modified ("aged") by sodium nitrite was subjected to similar treatments. ARPE-19 cells were then cultured to confluence onto the different surfaces. Fluorescently-labeled bovine rod outer segments (ROS) were fed to cells with or without αVβ5 integrin antibody. Image acquisition and phagocytosis quantification was performed by fluorescence microscopy and ImageJ analysis. RESULTS Cleaning old donor-derived BM with detergent does not increase the uptake of ROS, but a combination of cleaning and coating with ECM ligands significantly increases RPE phagocytosis (54.9 ± 6.2 vs. 83.5 ± 6.5 arbitrary units; P < 0.05) to levels closer to young donor BM (123.6 ± 9.9 arbitrary units). Similar effects were observed on nitrite-modified ARPE-ECM subjected to the same treatments. Incubation of αVβ5 blocking antibody with ROS significantly decreased RPE phagocytosis. CONCLUSIONS The detrimental effects of aging BM on RPE phagocytosis can be reversed by reengineering the BM surface with detergent cleaning and recoating with ECM ligands. TRANSLATION RELEVANCE These results demonstrate that the therapeutic success of transplanted RPE cells may require, at least in part, reengineering of diseased BM to make it a more suitable environment for attachment, survival and proper functioning of the RPE.
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Affiliation(s)
- Ernesto F Moreira
- Department of Ophthalmology Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA
| | - Hui Cai
- Department of Ophthalmology, Harkness Eye Institute, Columbia University, New York, NY, USA
| | - Tongalp H Tezel
- Department of Ophthalmology, Harkness Eye Institute, Columbia University, New York, NY, USA
| | - Mark A Fields
- Department of Ophthalmology Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA
| | - Lucian V Del Priore
- Department of Ophthalmology Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA
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Haneef AS, Downes S. Assessing the Suitability of Electrospun Poly(Ethylene Terephthalate) and Polystyrene as Cell Carrier Substrates for Potential Subsequent Implantation as a Synthetic Bruch's Membrane. INT J POLYM MATER PO 2015. [DOI: 10.1080/00914037.2014.945206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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10
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Heller JP, Martin KR. Enhancing RPE Cell-Based Therapy Outcomes for AMD: The Role of Bruch's Membrane. Transl Vis Sci Technol 2014. [DOI: 10.1167/tvst.3.4.4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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11
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Heller JP, Martin KR. Enhancing RPE Cell-Based Therapy Outcomes for AMD: The Role of Bruch's Membrane. Transl Vis Sci Technol 2014; 3:11. [PMID: 25068093 PMCID: PMC4108298 DOI: 10.1167/tvst.3.3.11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 02/09/2014] [Indexed: 12/22/2022] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of legal blindness in older people in the developed world. The disease involves damage to the part of the retina responsible for central vision. Degeneration of retinal pigment epithelial (RPE) cells, photoreceptors, and choriocapillaris may contribute to visual loss. Over the past decades, scientists and clinicians have tried to replace lost RPE cells in patients with AMD using cells from different sources. In recent years, advances in generating RPE cells from stem cells have been made and clinical trials are currently evaluating the safety and efficiency of replacing the degenerated RPE cell layer with stem cell-derived RPE cells. However, the therapeutic success of transplantation of stem cell-derived RPE cells may be limited unless the transplanted cells can adhere and survive in the long term in the diseased eye. One hallmark of AMD is the altered extracellular environment of Bruch's membrane to which the grafted cells have to adhere. Here, we discuss recent approaches to overcome the inhibitory environment of the diseased eye and to enhance the survival rate of transplanted RPE cells. Our aim is to highlight novel approaches that may have the potential to improve the efficacy of RPE transplantation for AMD in the future.
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Affiliation(s)
- Janosch P. Heller
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, United Kingdom
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, United Kingdom
| | - Keith R. Martin
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, United Kingdom
- Department of Ophthalmology, NIHR Biomedical Research Centre and Wellcome Trust-MRC Cambridge Stem Cell Institute, University of Cambridge, United Kingdom
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12
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Current treatment limitations in age-related macular degeneration and future approaches based on cell therapy and tissue engineering. J Ophthalmol 2014; 2014:510285. [PMID: 24672707 PMCID: PMC3941782 DOI: 10.1155/2014/510285] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 12/10/2013] [Indexed: 01/01/2023] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in the Western world. With an ageing population, it is anticipated that the number of AMD cases will increase dramatically, making a solution to this debilitating disease an urgent requirement for the socioeconomic future of the European Union and worldwide. The present paper reviews the limitations of the current therapies as well as the socioeconomic impact of the AMD. There is currently no cure available for AMD, and even palliative treatments are rare. Treatment options show several side effects, are of high cost, and only treat the consequence, not the cause of the pathology. For that reason, many options involving cell therapy mainly based on retinal and iris pigment epithelium cells as well as stem cells are being tested. Moreover, tissue engineering strategies to design and manufacture scaffolds to mimic Bruch's membrane are very diverse and under investigation. Both alternative therapies are aimed to prevent and/or cure AMD and are reviewed herein.
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13
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14
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Proliferative vitreoretinopathy after eye injuries: an overexpression of growth factors and cytokines leading to a retinal keloid. Mediators Inflamm 2013; 2013:269787. [PMID: 24198445 PMCID: PMC3806231 DOI: 10.1155/2013/269787] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 08/26/2013] [Indexed: 01/16/2023] Open
Abstract
Eye injury is a significant disabling worldwide health problem. Proliferative Vitreoretinopathy (PVR) is a common complication that develops in up to 40–60% of patients with an open-globe injury. Our knowledge about the pathogenesis of PVR has improved in the last decades. It seems that the introduction of immune cells into the vitreous, like in penetrating ocular trauma, triggers the production of growth factors and cytokines that come in contact with intra-retinal cells, like Müller cells and RPE cells. Growth factors and cytokines drive the cellular responses leading to PVR's development. Knowledge of the pathobiological and pathophysiological mechanisms involved in posttraumatic PVR is increasing the possibilities of management, and it is hoped that in the future our treatment strategies will evolve, in particular adopting a multidrug approach, and become even more effective in vision recovery. This paper reviews the current literature and clinical trial data on the pathogenesis of PVR and its correlation with ocular trauma and describes the biochemical/molecular events that will be fundamental for the development of novel treatment strategies. This literature review included PubMed articles published from 1979 through 2013. Only studies written in English were included.
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15
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Blenkinsop TA, Corneo B, Temple S, Stern JH. Ophthalmologic stem cell transplantation therapies. Regen Med 2013; 7:32-9. [PMID: 23210809 DOI: 10.2217/rme.12.77] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Vision loss is a major social issue, with more than 20 million people over the age of 18 years affected in the USA alone. Loss of vision is feared more than premature death or cardiovascular disease, according to a recent Society for Consumer Research group survey. The annual direct cost of medical care for the most prevalent eye disease, age-related macular degeneration, was estimated at US$255 billion in 2010 with an additional economic impact of US$88 billion due to lost productivity and the burden of family and community care for visual disability. With the blossoming of human stem cell research, regenerative treatments are now being developed that can help reduce this burden. Positive results from animal studies demonstrate that stem cell-based transplants can preserve and potentially improve vision. This has led to new clinical trials for several eye diseases that are yielding encouraging results. In the next few years, additional trials and longer-term results are anticipated to further develop ocular regenerative therapies, with the potential to revolutionize our approach to ophthalmic disease and damage.
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Affiliation(s)
- Timothy A Blenkinsop
- Neural Stem Cell Institute, Regenerative Research Foundation, One Discovery Drive, Rensselaer, NY12144, USA
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16
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Melville H, Carpiniello M, Hollis K, Staffaroni A, Golestaneh N. Stem cells: a new paradigm for disease modeling and developing therapies for age-related macular degeneration. J Transl Med 2013; 11:53. [PMID: 23452406 PMCID: PMC3599723 DOI: 10.1186/1479-5876-11-53] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 02/19/2013] [Indexed: 02/06/2023] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in people over age 55 in the U.S. and the developed world. This condition leads to the progressive impairment of central visual acuity. There are significant limitations in the understanding of disease progression in AMD as well as a lack of effective methods of treatment. Lately, there has been considerable enthusiasm for application of stem cell biology for both disease modeling and therapeutic application. Human embryonic stem cells and induced pluripotent stem cells (iPSCs) have been used in cell culture assays and in vivo animal models. Recently a clinical trial was approved by FDA to investigate the safety and efficacy of the human embryonic stem cell-derived retinal pigment epithelium (RPE) transplantation in sub-retinal space of patients with dry AMD These studies suggest that stem cell research may provide both insight regarding disease development and progression, as well as direction for therapeutic innovation for the millions of patients afflicted with AMD.
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Affiliation(s)
- Heather Melville
- Georgetown University School of Medicine, 3900 Reservoir Rd, Washington, DC 20057, USA
| | - Matthew Carpiniello
- Georgetown University School of Medicine, 3900 Reservoir Rd, Washington, DC 20057, USA
| | - Kia Hollis
- Georgetown University School of Medicine, 3900 Reservoir Rd, Washington, DC 20057, USA
| | - Andrew Staffaroni
- Georgetown University School of Medicine, 3900 Reservoir Rd, Washington, DC 20057, USA
| | - Nady Golestaneh
- Georgetown University School of Medicine, 3900 Reservoir Rd, Washington, DC 20057, USA
- Department of Ophthalmology, Georgetown University, School of Medicine, 3900 Reservoir Rd, Washington, DC 20057, USA
- Department of Neurology, Georgetown University, School of Medicine, 3900 Reservoir Rd, Washington, DC 20057, USA
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University, School of Medicine, 3900 Reservoir Rd, Washington, DC 20057, USA
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Treharne AJ, Thomson HAJ, Grossel MC, Lotery AJ. Developing methacrylate-based copolymers as an artificial Bruch's membrane substitute. J Biomed Mater Res A 2012; 100:2358-64. [PMID: 22528296 DOI: 10.1002/jbm.a.34178] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 02/14/2012] [Accepted: 03/05/2012] [Indexed: 11/11/2022]
Abstract
Age-related macular degeneration (AMD) is the most common cause of blindness in the developed world. There is currently no treatment for the cellular loss, which is characteristic of AMD. Transplantation of retinal pigment epithelium (RPE) cells represents a potential therapy. Because of AMD-related pathology in the native support, Bruch's membrane, transplanted RPE cells require a scaffold to reside on. We present here the development of an electrospun fibrous scaffold derived from methyl methacrylate and poly(ethylene glycol) (PEG) methacrylate for novel application as an RPE scaffold. Scaffolds were chemically modified to improve cell adhesion by functionalization not previously reported for this type of copolymer system. A human RPE cell line was used to investigate cell-scaffold interactions for up to two weeks in vitro. Scanning electron microscopy was used to characterize the fibrous scaffolds and confirm cell attachment. By day 15, cell area was significantly (p < 0.001) enhanced on scaffolds with chemical modification of the PEG chain terminus. In addition, significantly, less-apoptotic cell death was demonstrable on these modified surfaces.
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Affiliation(s)
- Andrew J Treharne
- Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, United Kingdom
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18
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Rowland TJ, Blaschke AJ, Buchholz DE, Hikita ST, Johnson LV, Clegg DO. Differentiation of human pluripotent stem cells to retinal pigmented epithelium in defined conditions using purified extracellular matrix proteins. J Tissue Eng Regen Med 2012; 7:642-53. [PMID: 22514096 DOI: 10.1002/term.1458] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 10/05/2011] [Accepted: 11/24/2011] [Indexed: 01/24/2023]
Abstract
A potential application of human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) is the generation of retinal pigmented epithelium (RPE) to treat age-related macular degeneration (AMD), a common but incurable retinal disease. RPE cells derived from hESCs (hESC-RPEs) and iPSCs (iPSC-RPEs) express essential RPE markers and can rescue visual function in animal models. However, standard differentiation protocols yield RPE cells at low frequency, especially from iPSC lines, and the common use of Matrigel and xenogeneic feeder cells is not compatible with clinical applications. The extracellular matrix (ECM) can affect differentiation, and therefore changes in ECM composition may improve the frequency of stem cell-RPE differentiation. We selected several purified ECM proteins and substrates, based on the in vivo RPE ECM environment, and tested their ability to support iPSC-RPE differentiation and maintenance. iPSCs differentiated on nearly all tested substrates developed pigmented regions, with Matrigel and mouse laminin-111 supporting the highest pigmentation frequencies. Although iPSC-RPEs cultured on the majority of the tested substrates expressed key RPE genes, only six substrates supported development of confluent monolayers with normal RPE morphology, including Matrigel and mouse laminin-111. iPSCs differentiated on mouse laminin-111 produced iPSC-RPEs expressing RPE proteins, and hESCs differentiated on mouse laminin-111 resulted in high yields of functional hESC-RPEs. This identification of key ECM proteins may assist with future scaffold designs and provide peptide sequences for use in synthetic, xeno-free, GMP-compliant generation of RPE from human pluripotent stem cells relevant to clinical translation.
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Affiliation(s)
- Teisha J Rowland
- Center for Stem Cell Biology and Engineering, University of California, Santa Barbara, CA 93106, USA
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Transplantation of amniotic membrane to the subretinal space in pigs. Stem Cells Int 2012; 2012:716968. [PMID: 22550516 PMCID: PMC3328183 DOI: 10.1155/2012/716968] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 12/22/2011] [Indexed: 12/22/2022] Open
Abstract
Purpose. To investigate the effect of transplanted amniotic membrane (AM) on subretinal wound healing. Methods. Nine Danish Landrace pigs had surgical removal of retinal pigment epithelium (RPE) and mechanical damage of Bruch's membrane (BM) and served as a control group. 15 pigs additionally had AM transplanted to the subretinal space. Results. AM significantly reduces choroidal neovascularisation when complete coverage of the induced defect is obtained (7 pigs) (P < 0.05). In cases where AM did not cover the rupture in BM choroidal tissue covered the transplanted membrane (8 pigs). AM is well tolerated in the subretinal space, causes only limited inflammation, and is covered with a monolayer of pigmented cells when in contact with the host RPE. Conclusions. AM modifies choroidal neovascularisation after BM damage and may serve as a basement membrane substitute for the RPE.
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20
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Zayas-Santiago A, Marmorstein AD, Marmorstein LY. Relationship of stokes radius to the rate of diffusion across Bruch's membrane. Invest Ophthalmol Vis Sci 2011; 52:4907-13. [PMID: 21642629 DOI: 10.1167/iovs.10-6595] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine the effect of Stokes radius (R(S)) on the diffusion of molecules through Bruch's membrane (BM), and to establish a system suitable for the analysis of diffusion through small (<2 mm(2)) samples of BM. METHODS Porcine BM/choroid (BM/Ch) was mounted in a modified Ussing chamber. A concentration gradient was simultaneously established for four tracers with R(S) values ranging from <1.0 to 6.15 nm. Samples were collected from both chambers at various time points up to 36 hours and the amount of each tracer was determined using quantitative gel exclusion chromatography. The integrity of samples was determined using scanning electron microscopy. RESULTS BM/Ch mounted in the chamber exhibited no obvious damage even after 36 hours in the chamber. Flux was significantly (P < 0.05) greater in the BM to Ch direction than that in the Ch to BM direction for only two of the tracers: cytosine and RNase A. Flux also was dependent on R(S); cytosine, the smallest tracer (R(S) < 1 nm), exhibited the greatest flux and ferritin (R(S) = 6.15 nm) the least. Permeability coefficients for each tracer were determined and exhibited a power relationship with R(S). CONCLUSIONS Flux was dependent on the direction of the concentration gradient and the R(S) of the individual tracers. We have successfully demonstrated that quantitative gel exclusion chromatography can be used to follow diffusion of a mixture of tracers across BM/Ch, and that we can measure flux across BM/Ch preparations with an exposed surface area as small as 1.8 mm(2).
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Affiliation(s)
- Astrid Zayas-Santiago
- Department of Ophthalmology and Vision Science, University of Arizona, Tucson, Arizona 85724, USA
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21
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Kramer MA, Andrews B, Hugar DL, Jaitli A, Larsen SB, Kline BP, McEllen KN, Agrawal N, Su SM, Dammu SA, Kammeyer RM, Ivanisevic A. Characterization of conformational adsorbate changes on a tissue-derived substrate using Fourier transform infrared spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:18083-18088. [PMID: 21067159 DOI: 10.1021/la1038766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Fourier transform infrared (FT-IR) spectroscopy is utilized to observe adsorbate interactions with a tissue-derived collagen scaffold extracted from the Bruch's membrane of pig eyes. The characterization includes conformational changes in isoleucine, polyisoleucine, collagen-binding peptide, RGD-tagged collagen-binding peptide, and laminin after adsorption onto the substrate. Isotopically labeled isoleucine is further utilized to understand changes in the biomolecular structure upon binding to a tissue-derived surface. The adsorbates associated with the collagen scaffold predominately through hydrophobic interactions and hydrogen bonding. The results of this study can be used to improve our understanding of surface chemistry changes during the engineering of biomimetic scaffolds before and after biomolecule adsorption.
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Affiliation(s)
- Marcus A Kramer
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States
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Wang NK, Tosi J, Kasanuki JM, Chou CL, Kong J, Parmalee N, Wert KJ, Allikmets R, Lai CC, Chien CL, Nagasaki T, Lin CS, Tsang SH. Transplantation of reprogrammed embryonic stem cells improves visual function in a mouse model for retinitis pigmentosa. Transplantation 2010; 89:911-9. [PMID: 20164818 PMCID: PMC2855750 DOI: 10.1097/tp.0b013e3181d45a61] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND To study whether C57BL/6J-Tyr/J (C2J) mouse embryonic stem (ES) cells can differentiate into retinal pigment epithelial (RPE) cells in vitro and then restore retinal function in a model for retinitis pigmentosa: Rpe65/Rpe65 C57BL6 mice. METHODS Yellow fluorescent protein (YFP)-labeled C2J ES cells were induced to differentiate into RPE-like structures on PA6 feeders. RPE-specific markers are expressed from differentiated cells in vitro. After differentiation, ES cell-derived RPE-like cells were transplanted into the subretinal space of postnatal day 5 Rpe65/Rpe65 mice. Live imaging of YFP-labeled C2J ES cells demonstrated survival of the graft. Electroretinograms (ERGs) were performed on transplanted mice to evaluate the functional outcome of transplantation. RESULTS RPE-like cells derived from ES cells sequentially express multiple RPE-specific markers. After transplantation, YFP-labeled cells can be tracked with live imaging for as long as 7 months. Although more than half of the mice were complicated with retinal detachments or tumor development, one fourth of the mice showed increased electroretinogram responses in the transplanted eyes. Rpe65/Rpe65 mice transplanted with RPE-like cells showed significant visual recovery during a 7-month period, whereas those injected with saline, PA6 feeders, or undifferentiated ES cells showed no rescue. CONCLUSIONS ES cells can differentiate, morphologically, and functionally, into RPE-like cells. Based on these findings, differentiated ES cells have the potential for the development of new therapeutic approaches for RPE-specific diseases such as certain forms of retinitis pigmentosa and macular degeneration. Nevertheless, stringent control of retinal detachment and teratoma development will be necessary before initiation of treatment trials.
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Affiliation(s)
- Nan-Kai Wang
- Department of Ophthalmology, Columbia University, New York City, NY
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou, Taiwan
- Chang Gung University College of Medicine, Taoyuan, Taiwan
- Department of Anatomy and Cell Biology, National Taiwan University, Taipei, Taiwan
| | - Joaquin Tosi
- Department of Ophthalmology, Columbia University, New York City, NY
| | | | - Chai Lin Chou
- Department of Ophthalmology, Columbia University, New York City, NY
| | - Jian Kong
- Department of Ophthalmology, Columbia University, New York City, NY
| | - Nancy Parmalee
- Department of Ophthalmology, Columbia University, New York City, NY
- Department of Genetics and Development, Columbia University, New York, NY
| | - Katherine J. Wert
- Department of Ophthalmology, Columbia University, New York City, NY
- Institute of Human Nutrient, Columbia University, New York, NY
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University, New York City, NY
- Department of Pathology and Cell Biology, Columbia University, New York, NY
| | - Chi-Chun Lai
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou, Taiwan
- Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Chung-Liang Chien
- Department of Anatomy and Cell Biology, National Taiwan University, Taipei, Taiwan
| | | | - Chyuan-Sheng Lin
- Department of Ophthalmology, Columbia University, New York City, NY
- Department of Pathology and Cell Biology, Columbia University, New York, NY
- Bernard and Shirlee Brown Glaucoma Laboratory, Columbia University, New York City, NY
| | - Stephen H. Tsang
- Department of Ophthalmology, Columbia University, New York City, NY
- Department of Pathology and Cell Biology, Columbia University, New York, NY
- Bernard and Shirlee Brown Glaucoma Laboratory, Columbia University, New York City, NY
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Afshari FT, Kwok JC, Andrews MR, Blits B, Martin KR, Faissner A, Ffrench-Constant C, Fawcett JW. Integrin activation or alpha 9 expression allows retinal pigmented epithelial cell adhesion on Bruch's membrane in wet age-related macular degeneration. ACTA ACUST UNITED AC 2010; 133:448-64. [PMID: 20159768 DOI: 10.1093/brain/awp319] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Retinal pigment epithelial cell malfunction is a causative feature of age-related macular degeneration, and transplantation of new retinal pigment epithelial cells is an attractive strategy to prevent further progression and visual loss. However, transplants have shown limited efficacy, mainly because transplanted cells fail to adhere and migrate onto pathological Bruch's membrane. Adhesion to Bruch's membrane is integrin-mediated. Ageing of Bruch's membrane leads to a decline in integrin ligands and, added to this, wet age-related macular degeneration leads to upregulation of anti-adhesive molecules such as tenascin-C. We have therefore investigated whether manipulation of integrin function in retinal pigment epithelial cells can restore their adhesion and migration on wet age-related macular degeneration-damaged Bruch's membrane. Using spontaneously immortalized human retinal pigment epithelial cells (adult retinal pigment epithelium-19), we show that adhesion and migration on the Bruch's membrane components is integrin-dependent and enhanced by integrin-activating agents manganese and TS2/16. These allowed cells to adhere and migrate on low concentrations of ligand, as would be found in aged Bruch's membrane. We next developed a method for stripping cells from Bruch's membrane so that adhesion and migration assays can be performed on its surface. Integrin activation had a moderate effect on enhancing retinal pigmented epithelial cell adhesion and migration on normal human and rat Bruch's membrane. However, on Bruch's membrane prepared from human wet age-related macular degeneration-affected eyes, adhesion was lower and integrin activation had a much greater effect. A candidate molecule for preventing retinal pigmented epithelial interaction with age-related macular degeneration-affected Bruch's membrane is tenascin-C which we confirm is present at high levels in wet age-related macular degeneration membrane. We show that tenascin-C is anti-adhesive for retinal pigmented epithelial cells, but after integrin activation, they can adhere and migrate on it using alphaVbeta3 integrin. Alternatively, we find that transduction of retinal pigmented epithelial cells with alpha9 integrin, a tenascin-C-binding integrin, led to a large increase in alpha9beta1-mediated adhesion and migration on tenascin-C. Both expression of alpha9 integrin and integrin activation greatly enhanced the ability of retinal pigment epithelial cells to adhere to tenascin-rich wet age-related macular degeneration-affected Bruch's membranes. Our results suggest that manipulation of retinal pigment epithelial cell integrins through integrin activating strategies, or expression of new integrins such as alpha9, could be effective in improving the efficacy of retinal pigment epithelial cell transplantation in wet age-related macular degeneration-affected eyes.
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Affiliation(s)
- Fardad T Afshari
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, UK
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25
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Mellough CB, Steel DHW, Lako M. Genetic basis of inherited macular dystrophies and implications for stem cell therapy. Stem Cells 2009; 27:2833-45. [PMID: 19551904 PMCID: PMC2962903 DOI: 10.1002/stem.159] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Accepted: 06/11/2009] [Indexed: 12/25/2022]
Abstract
Untreatable hereditary macular dystrophy (HMD) presents a major burden to society in terms of the resulting patient disability and the cost to the healthcare provision system. HMD results in central vision loss in humans sufficiently severe for blind registration, and key issues in the development of therapeutic strategies to target these conditions are greater understanding of the causes of photoreceptor loss and the development of restorative procedures. More effective and precise analytical techniques coupled to the development of transgenic models of disease have led to a prolific growth in the identification and our understanding of the genetic mutations that underly HMD. Recent successes in driving differentiation of pluripotent cells towards specific somatic lineages have led to the development of more efficient protocols that can yield enriched populations of a desired phenotype. Retinal pigmented epithelial cells and photoreceptors derived from these are some of the most promising cells that may soon be used in the treatment of specific HMD, especially since rapid developments in the field of induced pluripotency have now set the stage for the production of patient-derived stem cells that overcome the ethical and methodological issues surrounding the use of embryonic derivatives. In this review we highlight a selection of HMD which appear suitable candidates for combinatorial restorative therapy, focusing specifically on where those photoreceptor loss occurs. This technology, along with increased genetic screening, opens up an entirely new pathway to restore vision in patients affected by HMD.
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Affiliation(s)
- Carla B Mellough
- Institute of Human Genetics andInternational Centre for LifeNewcastle Upon Tyne, United Kingdom
| | - David HW Steel
- Sunderland Eye InfirmaryQueen Alexandra Road, Sunderland, Tyne and Wear, United Kingdom
| | - Majlinda Lako
- North East Stem Cell Institute, Newcastle University, International Centre for LifeNewcastle Upon Tyne, United Kingdom
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26
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Bhosale P, Li B, Sharifzadeh M, Gellermann W, Frederick JM, Tsuchida K, Bernstein PS. Purification and partial characterization of a lutein-binding protein from human retina. Biochemistry 2009; 48:4798-807. [PMID: 19402606 DOI: 10.1021/bi9004478] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dietary intake of lutein and zeaxanthin appears to be advantageous for protecting human retinal and macular tissues from degenerative disorders such as age-related macular degeneration. Selective concentration of just two of the many dietary carotenoids suggests that uptake and transport of these xanthophyll carotenoids into the human foveal region are mediated by specific xanthophyll-binding proteins such as GSTP1 which has previously been identified as the zeaxanthin-binding protein of the primate macula. Here, a membrane-associated human retinal lutein-binding protein (HR-LBP) was purified from human peripheral retina using ion-exchange chromatography followed by size-exclusion chromatography. After attaining 83-fold enrichment of HR-LBP, this protein exhibited a significant bathochromic shift of approximately 90 nm in association with lutein, and equilibrium binding studies demonstrated saturable, specific binding toward lutein with a K(D) of 0.45 muM. Examination for cross-reactivity with antibodies raised against known lutein-binding proteins from other organisms revealed consistent labeling of a major protein band of purified HR-LBP at approximately 29 kDa with an antibody raised against silkworm (Bombyx mori) carotenoid-binding protein (CBP), a member of steroidogenic acute regulatory (StAR) protein family with significant homology to many human StAR proteins. Immunolocalization with antibodies directed against either CBP or GSTP1 showed specific labeling of rod and cone inner segments, especially in the mitochondria-rich ellipsoid region. There was also strong labeling of the outer plexiform (Henle fiber) layer with anti-GSTP1. Such localizations compare favorably with the distribution of macular carotenoids as revealed by resonance Raman microscopy. Our results suggest that HR-LBP may facilitate lutein's localization to a region of the cell subject to considerable oxidative stress.
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Affiliation(s)
- Prakash Bhosale
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA
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Sistiabudi R, Paderi J, Panitch A, Ivanisevic A. Modification of native collagen with cell-adhesive peptide to promote RPE cell attachment on Bruch's membrane. Biotechnol Bioeng 2009; 102:1723-9. [DOI: 10.1002/bit.22215] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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28
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Fang IM, Yang CH, Yang CM, Chen MS. Overexpression of integrin α6 and β4 enhances adhesion and proliferation of human retinal pigment epithelial cells on layers of porcine Bruch's membrane. Exp Eye Res 2009; 88:12-21. [DOI: 10.1016/j.exer.2008.09.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Revised: 09/11/2008] [Accepted: 09/13/2008] [Indexed: 11/30/2022]
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Thumann G, Viethen A, Gaebler A, Walter P, Kaempf S, Johnen S, Salz AK. The in vitro and in vivo behaviour of retinal pigment epithelial cells cultured on ultrathin collagen membranes. Biomaterials 2008; 30:287-94. [PMID: 18929407 DOI: 10.1016/j.biomaterials.2008.09.039] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Accepted: 09/02/2008] [Indexed: 11/19/2022]
Abstract
The transplantation of pigment epithelial cells as a therapeutic modality for retinal degeneration requires that the transplanted cells form a monolayer in the subretinal space that will establish communication with photoreceptors. Since previous studies have shown that transplanted cells in suspension do not form a monolayer, it will be necessary to transplant preformed pigment epithelial cell monolayers at the location of the exposed photoreceptors. To establish cell monolayers, retinal pigment epithelial (RPE) cells were cultured on ultrathin collagen membranes. Cells were examined for morphology, for characteristics of differentiation and viability. Membrane degradation and long-term biocompatibility in vivo were assessed following subconjunctival and subretinal implantation in rabbits. These studies have shown that RPE cells adhere, proliferate, form monolayers, and acquire differentiated properties on a collagen membrane that has features similar to Bruch's membrane. Membranes transplanted subconjunctivally and subretinally exhibit excellent biocompatibility without any evidence of inflammation or rejection. RPE cells cultured on collagen membranes acquire differentiated characteristics similar to those of RPE cells in vivo and form complete monolayers that are amenable to be transplanted to the subretinal space. The collagen membranes are non-toxic and do not elicit any rejection or inflammatory response when implanted subconjunctivally or subretinally in rabbits.
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Affiliation(s)
- Gabriele Thumann
- Department of Ophthalmology, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany.
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Abstract
The retinal pigment epithelium (RPE) plays an important role in the physiology and pathophysiology of the vertebrate retina. The RPE absorbs fluid from the retinal extracellular space, via a proton-lactate-water co-transport mechanism located in the apical membrane of the epithelium. This mechanism can account for the apparent capability of the RPE to absorb water against an osmotic gradient. RPE cells participate in retinal wound healing. We have created a porcine model of experimental choroidal neovascularization (CNV). In this model, the CNV eventually becomes enveloped by seemingly proliferating RPE cells. By means of 5-bromo-2-deoxyuridine (BrdU) labelling, we studied the proliferation of RPE cells in the porcine eye after experimental posterior pole injury. Surprisingly, we found that only the peripheral RPE cells incorporated the BrdU label, indicating that central injury elicits peripheral RPE proliferation. This might suggest the existence of a peripheral pool of RPE stem cells. RPE cell proliferation plays a role in the pathological wound healing known as proliferative vitreoretinopathy. Antiproliferative agents have been tried to treat this condition but with little success so far. We report on a drug delivery system under development where a prodrug of the antimetabolite 5-fluoro-uracil (5-FU) is suspended in the silicone oil used as a surgical device in the treatment of proliferative vitreoretinopathy (PVR). The theoretical advantage of this approach is that it allows for long contact times between therapeutic, and non-toxic, concentrations of 5-FU and the RPE.
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Affiliation(s)
- Morten la Cour
- Eye Department, Copenhagen University Hospital, Glostrup, Denmark.
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31
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Stanzel BV, Englander M, Strick DJ, Sanislo SS, Huie P, Blumenkranz MS, Binder S, Marmor MF. Perspektive: Tissue engineering bei RPE-Transplantation in AMD. SPEKTRUM DER AUGENHEILKUNDE 2007. [DOI: 10.1007/s00717-007-0213-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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da Cruz L, Chen FK, Ahmado A, Greenwood J, Coffey P. RPE transplantation and its role in retinal disease. Prog Retin Eye Res 2007; 26:598-635. [PMID: 17920328 DOI: 10.1016/j.preteyeres.2007.07.001] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Retinal pigment epithelial (RPE) transplantation aims to restore the subretinal anatomy and re-establish the critical interaction between the RPE and the photoreceptor, which is fundamental to sight. The field has developed over the past 20 years with advances coming from a large body of animal work and more recently a considerable number of human trials. Enormous progress has been made with the potential for at least partial restoration of visual function in both animal and human clinical work. Diseases that have been treated with RPE transplantation demonstrating partial reversal of vision loss include primary RPE dystrophies such as the merTK dystrophy in the Royal College of Surgeons (RCS) rat and in humans, photoreceptor dystrophies as well as complex retinal diseases such as atrophic and neovascular age-related macular degeneration (AMD). Unfortunately, in the human trials the visual recovery has been limited at best and full visual recovery has not been demonstrated. Autologous full-thickness transplants have been used most commonly and effectively in human disease but the search for a cell source to replace autologous RPE such as embryonic stem cells, marrow-derived stem cells, umbilical cord-derived cells as well as immortalised cell lines continues. The combination of cell transplantation with other modalities of treatment such as gene transfer remains an exciting future prospect. RPE transplantation has already been shown to be capable of restoring the subretinal anatomy and improving photoreceptor function in a variety of retinal diseases. In the near future, refinements of current techniques are likely to allow RPE transplantation to enter the mainstream of retinal therapy at a time when the treatment of previously blinding retinal diseases is finally becoming a reality.
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Affiliation(s)
- Lyndon da Cruz
- Division of Cellular Therapy, Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK.
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Carvalho JF, Blank M, Shoenfeld Y. Vascular Endothelial Growth Factor (VEGF) in Autoimmune Diseases. J Clin Immunol 2007; 27:246-56. [PMID: 17340192 DOI: 10.1007/s10875-007-9083-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Accepted: 02/07/2007] [Indexed: 10/23/2022]
Abstract
Vascular endothelial growth factor (VEGF) is a potent stimulating factor for angiogenesis and vascular permeability. There are eight isoforms with different and sometimes overlapping functions. The mechanisms of action are under investigation with emerging insights into overlapping pathways and cross-talk between other receptors such as the neuropilins, which were not previously associated to angiogenesis. VEGF has important physiological actions on embryonic development, healing, and menstrual cycle. It also has a great role in pathological conditions that are associated to autoimmune diseases. There is considerable evidence in various autoimmune diseases such as in systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis of an interrelationship between the VEGF system and theses disorders. Serum levels of VEGF correlate with disease activity in a large number of autoimmune diseases and fall with the use of standard therapy. We raised the possible future therapeutic strategies in autoimmune diseases with the anti-VEGF or anti-VEGFR (receptor). So far, this therapy has been used in cancer and macular ocular degeneration in diabetes. This review outlines the evidence for VEGF participation in various autoimmune diseases and proposes lines for future research in this field.
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