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Mousavi M, Kahuam-López N, Iovieno A, Yeung SN. Global impact of COVID-19 on corneal donor tissue harvesting and corneal transplantation. Front Med (Lausanne) 2023; 10:1210293. [PMID: 37608828 PMCID: PMC10440952 DOI: 10.3389/fmed.2023.1210293] [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: 04/22/2023] [Accepted: 07/24/2023] [Indexed: 08/24/2023] Open
Abstract
Introduction The purpose of this review is to consolidate and examine the available literature on the coronavirus disease 2019 pandemic and its effect on corneal transplantation and eye banking. Methods A primary literature search was conducted using the PubMed (Medline) database with keywords and MeSH terms such as "corneal transplantation," "eye banks," "keratoplasty" and then were combined with COVID-19. Relevant articles through September 2022 were assessed and 25 articles were included in this review. Results Donor tissue volumes declined globally during lockdown periods due to a lower number of referrals and tighter tissue screening guidelines. Rates of elective surgeries decreased in the lockdown period compared to respective periods in previous years. However, changes in rates of emergency procedures were not uniform across different regions. Moreover, rates of different elective corneal grafts [i.e., penetrating keratoplasty (PK), endothelial keratoplasty (EK), or anterior lamellar keratoplasty (ALK)] were affected differently with the pattern of change being dependent on region-specific factors. Conclusion Both donor tissue volumes and rates of corneal transplant procedures were affected by lockdown restrictions. The underlying etiology of these changes differed by region. Examining the range of impact across many countries as well as the contributing factors involved will provide guidance for future global pandemics.
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Affiliation(s)
| | | | | | - Sonia N. Yeung
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada
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Ong HS, Riau AK, Yam GHF, Yusoff NZBM, Han EJY, Goh TW, Lai RC, Lim SK, Mehta JS. Mesenchymal Stem Cell Exosomes as Immunomodulatory Therapy for Corneal Scarring. Int J Mol Sci 2023; 24:7456. [PMID: 37108619 PMCID: PMC10144287 DOI: 10.3390/ijms24087456] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 04/14/2023] [Accepted: 04/15/2023] [Indexed: 04/29/2023] Open
Abstract
Corneal scarring is a leading cause of worldwide blindness. Human mesenchymal stem cells (MSC) have been reported to promote corneal wound healing through secreted exosomes. This study investigated the wound healing and immunomodulatory effects of MSC-derived exosomes (MSC-exo) in corneal injury through an established rat model of corneal scarring. After induction of corneal scarring by irregular phototherapeutic keratectomy (irrPTK), MSC exosome preparations (MSC-exo) or PBS vehicle as controls were applied to the injured rat corneas for five days. The animals were assessed for corneal clarity using a validated slit-lamp haze grading score. Stromal haze intensity was quantified using in-vivo confocal microscopy imaging. Corneal vascularization, fibrosis, variations in macrophage phenotypes, and inflammatory cytokines were evaluated using immunohistochemistry techniques and enzyme-linked immunosorbent assays (ELISA) of the excised corneas. Compared to the PBS control group, MSC-exo treatment group had faster epithelial wound closure (0.041), lower corneal haze score (p = 0.002), and reduced haze intensity (p = 0.004) throughout the follow-up period. Attenuation of corneal vascularisation based on CD31 and LYVE-1 staining and reduced fibrosis as measured by fibronectin and collagen 3A1 staining was also observed in the MSC-exo group. MSC-exo treated corneas also displayed a regenerative immune phenotype characterized by a higher infiltration of CD163+, CD206+ M2 macrophages over CD80+, CD86+ M1 macrophages (p = 0.023), reduced levels of pro-inflammatory IL-1β, IL-8, and TNF-α, and increased levels of anti-inflammatory IL-10. In conclusion, topical MSC-exo could alleviate corneal insults by promoting wound closure and reducing scar development, possibly through anti-angiogenesis and immunomodulation towards a regenerative and anti-inflammatory phenotype.
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Affiliation(s)
- Hon Shing Ong
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
- Corneal and External Diseases Department, Singapore National Eye Centre, Singapore 168751, Singapore
| | - Andri K. Riau
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Gary Hin-Fai Yam
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | | | - Evelina J. Y. Han
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore
| | - Tze-Wei Goh
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore
| | - Ruenn Chai Lai
- Institute of Medical Biology & Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore 138648, Singapore
| | - Sai Kiang Lim
- Institute of Medical Biology & Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore 138648, Singapore
| | - Jodhbir S. Mehta
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
- Corneal and External Diseases Department, Singapore National Eye Centre, Singapore 168751, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
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Ballouz D, Issa R, Sawant OB, Hurlbert S, Titus MS, Zhou Y, Musch DC, Majmudar PA, Kumar A, Mian SI. COVID-19 and Eye Banking: Ongoing Impacts of the Pandemic. Cornea 2023; 42:89-96. [PMID: 36256386 DOI: 10.1097/ico.0000000000003137] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 07/25/2022] [Indexed: 11/25/2022]
Abstract
PURPOSE The purpose of this study was to assess the impact of ongoing waves of the COVID-19 pandemic and resulting guidelines on the corneal donor pool with resumption of clinical operations. METHODS A retrospective analysis of donors deemed eligible for corneal transplantation at an eye bank from July 1, 2020, through December 31, 2021. Donors ineligible due to meeting Eye Bank Association of America (EBAA) COVID-19 guidelines or a positive postmortem COVID-19 testing were examined. The correlation between COVID-19 rule outs and state COVID positivity was calculated. The number of scheduled surgeries, suitable corneas, imports, and international exports was compared with a pre-COVID period. Postmortem testing was reduced for the final 5 months of the study, and numbers were compared before and after the policy change. RESULTS 2.85% of referrals to the eye bank were ruled out because of EBAA guidelines. 3.2% of postmortem tests were positive or indeterminate resulting in an ineligible tissue donor (0.42% of referrals). Over the 18-month period, there was a 4.30% shortage of suitable corneas compared with transplantation procedures. There was a significant correlation between postmortem testing and state COVID-19 positivity (r = 0.37, P <0.01), but not with EBAA guidelines (r = 0.19, P = 0.07). When postmortem testing was reduced, significantly more corneas were exported internationally. CONCLUSIONS Although corneal transplant procedures were back to normal levels, there was a shortage of suitable corneal tissue. The discontinuation of postmortem testing was associated with a significant increase in international exports of corneal donor tissue.
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Affiliation(s)
- Dena Ballouz
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
| | - Rafik Issa
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
| | - Onkar B Sawant
- Center for Vision and Eye Banking Research, Eversight, Cleveland, OH
| | - Susan Hurlbert
- Department of Clinical Operations, Eversight, Ann Arbor, MI
| | | | - Yunshu Zhou
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
- Center for Eye Policy and Innovation, University of Michigan, Ann Arbor, MI
| | - David C Musch
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
- Department of Epidemiology, University of Michigan, Ann Arbor, MI
- Department of Ophthalmology, Rush University, Chicago, IL; and
| | - Parag A Majmudar
- Department of Epidemiology, University of Michigan, Ann Arbor, MI
- Department of Ophthalmology, Rush University, Chicago, IL; and
| | - Ashok Kumar
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University, Detroit, MI
| | - Shahzad I Mian
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI
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