1
|
Kurzawa-Akanbi M, Tzoumas N, Corral-Serrano JC, Guarascio R, Steel DH, Cheetham ME, Armstrong L, Lako M. Pluripotent stem cell-derived models of retinal disease: Elucidating pathogenesis, evaluating novel treatments, and estimating toxicity. Prog Retin Eye Res 2024; 100:101248. [PMID: 38369182 DOI: 10.1016/j.preteyeres.2024.101248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 02/20/2024]
Abstract
Blindness poses a growing global challenge, with approximately 26% of cases attributed to degenerative retinal diseases. While gene therapy, optogenetic tools, photosensitive switches, and retinal prostheses offer hope for vision restoration, these high-cost therapies will benefit few patients. Understanding retinal diseases is therefore key to advance effective treatments, requiring in vitro models replicating pathology and allowing quantitative assessments for drug discovery. Pluripotent stem cells (PSCs) provide a unique solution given their limitless supply and ability to differentiate into light-responsive retinal tissues encompassing all cell types. This review focuses on the history and current state of photoreceptor and retinal pigment epithelium (RPE) cell generation from PSCs. We explore the applications of this technology in disease modelling, experimental therapy testing, biomarker identification, and toxicity studies. We consider challenges in scalability, standardisation, and reproducibility, and stress the importance of incorporating vasculature and immune cells into retinal organoids. We advocate for high-throughput automation in data acquisition and analyses and underscore the value of advanced micro-physiological systems that fully capture the interactions between the neural retina, RPE, and choriocapillaris.
Collapse
|
2
|
Azrad Leibovitch T, Farah N, Markus A, Mandel Y. A novel GCaMP6f-RCS rat model for studying electrical stimulation in the degenerated retina. Front Cell Dev Biol 2024; 12:1386141. [PMID: 38711618 PMCID: PMC11070775 DOI: 10.3389/fcell.2024.1386141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 03/25/2024] [Indexed: 05/08/2024] Open
Abstract
Background: Retinal prostheses aim to restore vision by electrically stimulating the remaining viable retinal cells in Retinal Degeneration (RD) cases. Research in this field necessitates a comprehensive analysis of retinal ganglion cells' (RGCs) responses to assess the obtained visual acuity and quality. Here we present a novel animal model which facilitates the optical recording of RGCs activity in an RD rat. This model can significantly enhance the functional evaluation of vision restoration treatments. Methods: The development of the novel rat model is based on crossbreeding a retinal degenerated Royal College of Surgeons (RCS) rat with a transgenic line expressing the genetic calcium indicator GCaMP6f in the RGCs. Characterization of the model was achieved using Optical Coherence Tomography (OCT) imaging, histology, and electroretinography (ERG) at the ages of 4, 8, and 12 weeks. Additionally, optical recordings of RGCs function in response to ex-vivo subretinal electrical stimulations were performed. Results: Histological investigations confirmed the high expression of GCaMP6f in the RGCs and minimal expression in the inner nuclear layer (INL). OCT imaging and histological studies revealed the expected gradual retinal degeneration, as evident by the decrease in retinal thickness with age and the formation of subretinal debris. This degeneration was further confirmed by ERG recordings, which demonstrated a significant decrease in the b-wave amplitude throughout the degeneration process, culminating in its absence at 12 weeks in the GCaMP6f-RCS rat. Importantly, the feasibility of investigating subretinal stimulation was demonstrated, revealing a consistent increase in activation threshold throughout degeneration. Furthermore, an increase in the diameter of the activated area with increasing currents was observed. The spatial spread of the activation area in the GCaMP6f-RCS rat was found to be smaller and exhibited faster activation dynamics compared with the GCaMP6f-LE strain. Conclusion: This novel animal model offers an opportunity to deepen our understanding of prosthetically induced retinal responses, potentially leading to significant advancements in prosthetic interventions in visual impairments.
Collapse
Affiliation(s)
- Tamar Azrad Leibovitch
- Bar Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar Ilan University, Ramat Gan, Israel
- Faculty of Life Sciences, School of Optometry and Visual Science, Bar Ilan University, Ramat Gan, Israel
| | - Nairouz Farah
- Bar Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar Ilan University, Ramat Gan, Israel
- Faculty of Life Sciences, School of Optometry and Visual Science, Bar Ilan University, Ramat Gan, Israel
| | - Amos Markus
- Bar Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar Ilan University, Ramat Gan, Israel
- Faculty of Life Sciences, School of Optometry and Visual Science, Bar Ilan University, Ramat Gan, Israel
| | - Yossi Mandel
- Bar Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar Ilan University, Ramat Gan, Israel
- Faculty of Life Sciences, School of Optometry and Visual Science, Bar Ilan University, Ramat Gan, Israel
| |
Collapse
|
3
|
Shpun G, Farah N, Chemla Y, Markus A, Leibovitch TA, Lasnoy E, Gerber D, Zalevsky Z, Mandel Y. Optimizing the fabrication of a 3D high-resolution implant for neural stimulation. J Biol Eng 2023; 17:55. [PMID: 37620951 PMCID: PMC10463680 DOI: 10.1186/s13036-023-00370-8] [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: 09/12/2022] [Accepted: 07/24/2023] [Indexed: 08/26/2023] Open
Abstract
BACKGROUND Tissue-integrated micro-electronic devices for neural stimulation hold great potential in restoring the functionality of degenerated organs, specifically, retinal prostheses, which are aimed at vision restoration. The fabrication process of 3D polymer-metal devices with high resolution and a high aspect-ratio (AR) is very complex and faces many challenges that impair its functionality. APPROACH Here we describe the optimization of the fabrication process of a bio-functionalized 3D high-resolution 1mm circular subretinal implant composed of SU-8 polymer integrated with dense gold microelectrodes (23μm pitch) passivated with 3D micro-well-like structures (20μm diameter, 3μm resolution). The main challenges were overcome by step-by-step planning and optimization while utilizing a two-step bi-layer lift-off process; bio-functionalization was carried out by N2 plasma treatment and the addition of a bio-adhesion molecule. MAIN RESULTS In-vitro and in-vivo investigations, including SEM and FIB cross section examinations, revealed a good structural design, as well as a good long-term integration of the device in the rat sub-retinal space and cell migration into the wells. Moreover, the feasibility of subretinal neural stimulation using the fabricated device was demonstrated in-vitro by electrical activation of rat's retina. CONCLUSIONS The reported process and optimization steps described here in detail can aid in designing and fabricating retinal prosthetic devices or similar neural implants.
Collapse
Affiliation(s)
- Gal Shpun
- The Alexander Kofkin Faculty of Engineering, Bar Ilan University, 5290002, Ramat Gan, Israel
- Faculty of Life Sciences, School of Optometry & Visual Science, Bar Ilan University, 5290002, Ramat Gan, Israel
- Bar Ilan Institute for Nanotechnology & Advanced Materials (BINA), Bar Ilan University, 5290002, Ramat Gan, Israel
| | - Nairouz Farah
- Faculty of Life Sciences, School of Optometry & Visual Science, Bar Ilan University, 5290002, Ramat Gan, Israel
- Bar Ilan Institute for Nanotechnology & Advanced Materials (BINA), Bar Ilan University, 5290002, Ramat Gan, Israel
| | - Yoav Chemla
- Faculty of Life Sciences, School of Optometry & Visual Science, Bar Ilan University, 5290002, Ramat Gan, Israel
- Bar Ilan Institute for Nanotechnology & Advanced Materials (BINA), Bar Ilan University, 5290002, Ramat Gan, Israel
| | - Amos Markus
- Faculty of Life Sciences, School of Optometry & Visual Science, Bar Ilan University, 5290002, Ramat Gan, Israel
- Bar Ilan Institute for Nanotechnology & Advanced Materials (BINA), Bar Ilan University, 5290002, Ramat Gan, Israel
| | - Tamar Azrad Leibovitch
- Faculty of Life Sciences, School of Optometry & Visual Science, Bar Ilan University, 5290002, Ramat Gan, Israel
- Bar Ilan Institute for Nanotechnology & Advanced Materials (BINA), Bar Ilan University, 5290002, Ramat Gan, Israel
| | - Erel Lasnoy
- Faculty of Life Sciences, School of Optometry & Visual Science, Bar Ilan University, 5290002, Ramat Gan, Israel
- Bar Ilan Institute for Nanotechnology & Advanced Materials (BINA), Bar Ilan University, 5290002, Ramat Gan, Israel
| | - Doron Gerber
- Bar Ilan Institute for Nanotechnology & Advanced Materials (BINA), Bar Ilan University, 5290002, Ramat Gan, Israel
| | - Zeev Zalevsky
- The Alexander Kofkin Faculty of Engineering, Bar Ilan University, 5290002, Ramat Gan, Israel
- Bar Ilan Institute for Nanotechnology & Advanced Materials (BINA), Bar Ilan University, 5290002, Ramat Gan, Israel
| | - Yossi Mandel
- Faculty of Life Sciences, School of Optometry & Visual Science, Bar Ilan University, 5290002, Ramat Gan, Israel.
- Bar Ilan Institute for Nanotechnology & Advanced Materials (BINA), Bar Ilan University, 5290002, Ramat Gan, Israel.
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel.
| |
Collapse
|
4
|
Onyak JR, Vergara MN, Renna JM. Retinal organoid light responsivity: current status and future opportunities. Transl Res 2022; 250:98-111. [PMID: 35690342 DOI: 10.1016/j.trsl.2022.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/31/2022] [Accepted: 06/01/2022] [Indexed: 11/30/2022]
Abstract
The ability to generate human retinas in vitro from pluripotent stem cells opened unprecedented opportunities for basic science and for the development of therapeutic approaches for retinal degenerative diseases. Retinal organoid models not only mimic the histoarchitecture and cellular composition of the native retina, but they can achieve a remarkable level of maturation that allows them to respond to light stimulation. However, studies evaluating the nature, magnitude, and properties of light-evoked responsivity from each cell type, in each retinal organoid layer, have been sparse. In this review we discuss the current understanding of retinal organoid function, the technologies used for functional assessment in human retinal organoids, and the challenges and opportunities that lie ahead.
Collapse
Affiliation(s)
| | - M Natalia Vergara
- CellSight Ocular Stem Cell and Regeneration Program, Sue Anschutz-Rodgers Eye Center, University of Colorado School of Medicine, Aurora, Colorado.
| | - Jordan M Renna
- Department of Biology, The University of Akron, Akron, Ohio.
| |
Collapse
|