Development of a new tissue injector for subretinal transplantation of human embryonic stem cell derived retinal pigmented epithelium
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.
Additional Information© 2017 The Author(s). This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Authors' contributions: Rodrigo A. Brant Fernandes, Francisco R. Stefanini performed procedures, analyzed and interpreted data and were major contributors in writing the manuscript. Paulo Falabella, Michael J. Koss, Bruno Diniz and Ramiro Ribeiro also performed procedures and reviewed analysis, and contributed in writing the manuscript. Paulo Schor, Mauricio Maia and Fernando M. Penha worked on a thorough and critical review of the manuscript. Trent Wells and Yu-Chong Tai worked on development and improving the injector tool. David R. Hinton performed histological analysis and reviewed the manuscript critically. Mark Humayun worked on conception and design of the study, as well as on development of the tool. All authors read and approved the final manuscript. Acknowledgements: Not applicable. Competing interests: RABF is a patent holder. DRH and MSH are patent holders. DRH and MSH are founders and have equity in Regenerative Patch Technologies (RPT) and have received grant funding from California Institute of Regenerative Medicine. The remaining authors report no relevant financial disclosures. Availability of data and materials: The data that support the findings of this study are available from the corresponding author upon reasonable request. Consent for publication: Not applicable. Ethics approval and consent to participate: This study was approved by the Animal Care and Use Committee (IACUC) at the University of Southern California and also Animal Care and Use Committee (CEUA) at the Federal University of Sao Paulo (CEUA N 1710021113). Funding: Supported by the California Institute of Regenerative Medicine (CIRM), grant CIRM DRI-01444, CIRM CL1-00521; an unrestricted departmental grant from Research to Prevent Blindness, New York, NY 10022; the CAPES Foundation, Brasília, Brazil, [BEX 2326-11-6 (Brant); BEX 4601-14-9 (Falabella)], CNPq (The National Council of Research, Brasília, Brazil); the German Research Foundation DFG Ko4294/1-1 (Berlin, Germany); the UCSB Institute for Collaborative Biotechnologies through grant W911NF-09-0001 from the U.S. Army Research Office. The content of the information does not necessarily reflect the position or the policy of the U.S. Government, and no official endorsement should be inferred.
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