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Na KS, Fernandes-Cunha GM, Varela IB, Lee HJ, Seo YA, Myung D. Effect of mesenchymal stromal cells encapsulated within polyethylene glycol-collagen hydrogels formed in situ on alkali-burned corneas in an ex vivo organ culture model. Cytotherapy 2021; 23:500-509. [PMID: 33752960 PMCID: PMC10069134 DOI: 10.1016/j.jcyt.2021.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 02/01/2021] [Accepted: 02/01/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND AIMS Corneal inflammation after alkali burns often results in vision loss due to corneal opacification and neovascularization. Mesenchymal stem cells (MSCs) and their secreted factors (secretome) have been studied for their anti-inflammatory and anti-angiogenic properties with encouraging results. However, topical instillation of MSCs or their secretome is often accompanied by issues related to delivery or rapid washout. Polyethylene glycol (PEG) and collagen are well-known biomaterials used extensively in scaffolds for tissue engineering. To effectively suppress alkaline burn-induced corneal injury, the authors proposed encapsulating MSCs within collagen gels cross-linked with multi-functional PEG-succinimidyl esters as a means to deliver the secretome of immobilized MSCs. METHODS Human MSCs were added to a neutralized collagen solution and mixed with a solution of four-arm PEG-N-hydroxysuccinimide. An ex vivo organ culture was conducted using rabbit corneas injured by alkali burn. MSCs were encapsulated within PEG-collagen hydrogels and injected onto the wounded cornea immediately following alkali burn and washing. Photographs of the ocular surface were taken over a period of 7 days after the alkali burn and processed for immunohistochemical evaluation. Samples were split into three groups: injury without treatment, MSCs alone, and MSCs encapsulated within PEG-collagen hydrogels. RESULTS All corneas in ex vivo organ culture lost their transparency immediately after alkali burn, and only the groups treated with MSCs and MSCs encapsulated within PEG-collagen hydrogels recovered some transparency after 7 days. Immunohistochemical analysis revealed increased expression of vimentin in the anterior corneal stroma of the group without treatment indicative of fibrotic healing, whereas less stromal vimentin was detected in the group containing MSCs encapsulated within the PEG-collagen hydrogels. CONCLUSIONS PEG-collagen hydrogels enable the encapsulation of viable MSCs capable of releasing secreted factors onto the ocular surface. Encapsulating MSCs within PEG-collagen hydrogels may be a promising method for delivering their therapeutic benefits in cases of ocular inflammatory diseases, such as alkali burn injuries.
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Affiliation(s)
- Kyung-Sun Na
- Department of Ophthalmology, Yeouido St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | | | | | - Hyun Jong Lee
- Department of Chemical and Biological Engineering, Gachon University, Seongnam-si, South Korea
| | - Youngyoon Amy Seo
- Department of Ophthalmology, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California, USA
| | - David Myung
- Department of Ophthalmology, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California, USA; Department of Chemical and Biological Engineering, Gachon University, Seongnam-si, South Korea; VA Palo Alto HealthCare System, Palo Alto, California, USA.
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Jiang GJ, Li Y, You XG, Fan TJ. Establish an In Vitro Cell Model to Explore the Impacts of UVA on Human Corneal Endothelial Wound Healing. Curr Eye Res 2020; 45:1065-1073. [PMID: 32090638 DOI: 10.1080/02713683.2020.1718166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE To provide scientific data for clinical practice in making strategies for accelerating corneal endothelial wound healing, we investigated the impact of UVA on the corneal endothelial wound healing process and the underlying mechanism using an in vitro cell model. MATERIALS AND METHODS An in vitro cell model for corneal endothelial wound healing was established by scratching the in vitro cultured human corneal endothelial cell (HCEnC) confluent layer. Then, we investigated the impacts of UVA irradiation and Ascorbic acid-2-phosphate (Asc-2p) on the wound healing process of the in vitro HCEnC model by examining wound-healing index, F-actin+ rate, Ki-67+ rate, and ROS production. RESULTS After scratching, the Ki-67+ and F-actin+ HCEnCs occupied the scratching gap. Furthermore, the F-actin+ rates were significantly higher than Ki-67+ rates in the wound closure area. After irradiated with UVA, the wound-healing indexes, Ki-67+ rates and F-actin+ rates of the wound-healing model significantly reduced, whereas the ROS production significantly increased in a dose-dependent manner. Pretreatment with Asc-2p significantly reduced the ROS production as well as increased the wound-healing indexes, Ki-67+rates and F-actin+ rates of the UVA irradiated wound-healing model. CONCLUSION The migration of HCEnC plays a major role in the wound healing process of the established cell model, which is like the wound healing process in vivo. UVA decreases the wound closure of the in vitro HCEnC model dose-dependently, while antioxidant Asc-2p can attenuate the damage to UVA to HCEnCs probably via reducing ROS to improve their migration.
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Affiliation(s)
- Guo-Jian Jiang
- Laboratory for Corneal Tissue Engineering, College of Marine Life Sciences, Ocean University of China , Qingdao, Shandong Province, China
| | - Ying Li
- Laboratory for Corneal Tissue Engineering, College of Marine Life Sciences, Ocean University of China , Qingdao, Shandong Province, China
| | - Xin-Guo You
- Laboratory for Corneal Tissue Engineering, College of Marine Life Sciences, Ocean University of China , Qingdao, Shandong Province, China
| | - Ting-Jun Fan
- Laboratory for Corneal Tissue Engineering, College of Marine Life Sciences, Ocean University of China , Qingdao, Shandong Province, China
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Singh A, Abd AJ, Al-Mashahedah A, Kanwar JR. Corneal Haze, Refractive Surgery, and Implications for Choroidal Neovascularization. DRUG DELIVERY FOR THE RETINA AND POSTERIOR SEGMENT DISEASE 2018:439-477. [DOI: 10.1007/978-3-319-95807-1_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Tuncel N, Yildirim N, Gurer F, Basmak H, Uzuner K, Sahinturk V, Gursoy H. Effect of vasoactive intestinal peptide on the wound healing of alkali-burned corneas. Int J Ophthalmol 2016; 9:204-10. [PMID: 26949636 DOI: 10.18240/ijo.2016.02.04] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 04/29/2015] [Indexed: 12/16/2022] Open
Abstract
AIM To study the effect of vasoactive intestinal peptide (VIP) on wound healing in experimental alkali burns of the cornea. METHODS Twenty-seven albino rabbits, weighing 3.2±0.75 kg were used. Alkali burns were induced on corneas by applying 10 mm Whatman paper No:50 soaked in 1 mol/L NaOH. They have further classified into 5 groups as follows: 1) control group given no treatment (n=5); 2) VIP given subconjunctivally (n=6); 3) VIP injected into anterior chamber (n=6); 4) NaCl 0.9% given subconjunctivally (n=5); 5) NaCl 0.9% given into the anterior chamber (n=5). All treatment protocols except control group were followed by topical eye drops composed of VIP at two hourly intervals for one week from 8 a.m. to 6 p.m. RESULTS VIP treated groups of rabbits with alkali burns were found to have better wound healing findings histo-pathologically when compared to those of control group who have received no treatment on day 30. No differences were observed between groups in respect to degree of polymorphonuclear leukocytes (PMNL) infiltration and degree of loss of amorphous substrate on day 15. However, PMNL infiltration and degree of loss of amorphous substrate were lower in Groups 2 and 3 when compared to that of control group on day 30 (P<0.05). CONCLUSION We have shown that VIP has positive effects on alkali induced corneal burns. VIP may inhibit PMNL migration to cornea through an immunomodulatory effect. Inhibition of PMNL migration might reduce the release of collagenases and this might prevent the extracellular amorphous substance loss.
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Affiliation(s)
- Nese Tuncel
- Department of Physiology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26480, Turkey
| | - Nilgun Yildirim
- Department of Ophthalmology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26480, Turkey
| | - Firdevs Gurer
- Department of Histology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26480, Turkey
| | - Hikmet Basmak
- Department of Ophthalmology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26480, Turkey
| | - Kubilay Uzuner
- Department of Physiology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26480, Turkey
| | - Varol Sahinturk
- Department of Histology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26480, Turkey
| | - Huseyin Gursoy
- Department of Ophthalmology, Eskisehir Osmangazi University Medical Faculty, Eskisehir 26480, Turkey
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Abstract
Corneal wound healing is a complex process involving cell death, migration, proliferation, differentiation, and extracellular matrix remodeling. Many similarities are observed in the healing processes of corneal epithelial, stromal and endothelial cells, as well as cell-specific differences. Corneal epithelial healing largely depends on limbal stem cells and remodeling of the basement membrane. During stromal healing, keratocytes get transformed to motile and contractile myofibroblasts largely due to activation of transforming growth factor-β (TGF-β) system. Endothelial cells heal mostly by migration and spreading, with cell proliferation playing a secondary role. In the last decade, many aspects of wound healing process in different parts of the cornea have been elucidated, and some new therapeutic approaches have emerged. The concept of limbal stem cells received rigorous experimental corroboration, with new markers uncovered and new treatment options including gene and microRNA therapy tested in experimental systems. Transplantation of limbal stem cell-enriched cultures for efficient re-epithelialization in stem cell deficiency and corneal injuries has become reality in clinical setting. Mediators and course of events during stromal healing have been detailed, and new treatment regimens including gene (decorin) and stem cell therapy for excessive healing have been designed. This is a very important advance given the popularity of various refractive surgeries entailing stromal wound healing. Successful surgical ways of replacing the diseased endothelium have been clinically tested, and new approaches to accelerate endothelial healing and suppress endothelial-mesenchymal transformation have been proposed including Rho kinase (ROCK) inhibitor eye drops and gene therapy to activate TGF-β inhibitor SMAD7. Promising new technologies with potential for corneal wound healing manipulation including microRNA, induced pluripotent stem cells to generate corneal epithelium, and nanocarriers for corneal drug delivery are discussed. Attention is also paid to problems in wound healing understanding and treatment, such as lack of specific epithelial stem cell markers, reliable identification of stem cells, efficient prevention of haze and stromal scar formation, lack of data on wound regulating microRNAs in keratocytes and endothelial cells, as well as virtual lack of targeted systems for drug and gene delivery to select corneal cells.
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Affiliation(s)
- Alexander V Ljubimov
- Eye Program, Board of Governors Regenerative Medicine Institute, Departments of Biomedical Sciences and Neurosurgery, Cedars-Sinai Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
| | - Mehrnoosh Saghizadeh
- Eye Program, Board of Governors Regenerative Medicine Institute, Departments of Biomedical Sciences and Neurosurgery, Cedars-Sinai Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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Feng Y, Foster J, Mi S, Chen B, Connon CJ. Influence of substrate on corneal epithelial cell viability within ocular surface models. Exp Eye Res 2012; 101:97-103. [DOI: 10.1016/j.exer.2012.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 04/18/2012] [Accepted: 05/17/2012] [Indexed: 12/13/2022]
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Cejka C, Ardan T, Sirc J, Michálek J, Brůnová B, Cejková J. The influence of various toxic effects on the cornea and changes in corneal light transmission. Graefes Arch Clin Exp Ophthalmol 2010; 248:1749-56. [PMID: 20596718 DOI: 10.1007/s00417-010-1438-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 06/04/2010] [Accepted: 06/12/2010] [Indexed: 11/28/2022] Open
Abstract
PURPOSE Normal corneal hydration is necessary for the maintenance of corneal transparency. Damage of the corneal epithelium or endothelium by various external influences disturbs the mechanism by which the cornea maintains normal hydration and transparency. The cornea swells, and the corneal thickness increases, resulting in increased scatter and the development of corneal opacity. The transmission of light across the cornea is changed. The purpose of this study is to investigate spectrophotometrically the corneal light transmission under the influence of the various factors affecting the cornea. METHODS We developed a spectrophotometric method to measure the light transmission across the cornea under the influence of various factors affecting the cornea, such as treatment with 0.9% NaCl, saline, or phosphate buffered saline (PBS), solutions employed as placebo eye drops (negative controls) in experimental studies, agents toxic to the cornea, such as diluted acids or alkalis. The method distinguishes between changes in corneal light transmission caused by altered corneal thickness (the level of hydration) and changes resulting from other corneal disturbances which in turn affect corneal light transmission. RESULTS The results obtained show that the corneal light transmission is decreased following the application of toxic substances on the corneal surface. This decrease is highly dependent on the severity of the corneal injury evoked by individual noxes, and the resulting changes in corneal hydration and transparency. CONCLUSIONS The influence of various influences applied to the cornea, manifested as changes in corneal light transmission, can be measured using our spectrophotometric method with a high degree of sensitivity.
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Affiliation(s)
- Cestmír Cejka
- Laboratory of Eye Histochemistry and Pharmacology, Institute of Experimental Medicine, Center of Excellence, Academy of Sciences of the Czech Republic, Vídeňská 1083, 14220, Prague 4, Czech Republic.
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Abstract
Practical relevance Corneal ulcers in cats (ulcerative keratitis) are a common presenting complaint, and are a frequent sequela to feline herpesvirus (FHV-1) infection. In fact, it is fair to assume an FHV-1 aetiology until proven otherwise. In practice, therefore, many cases of corneal ulceration can be treated medically, but treatment can frequently be challenging, with the need to tailor therapy carefully to the type of ulcer, the individual cat and its temperament. Patient group All age groups and breeds can suffer with ulcerative keratitis although some breeds are over-represented for some types of corneal ulceration. Evidence base The scientific literature on feline ulcerative keratitis is extensive, particularly that related to FHV-1 infection. This article reviews the medical treatment options for corneal ulceration in cats with reference to the current evidence base.
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Holmes AM, Creton S, Chapman K. Working in partnership to advance the 3Rs in toxicity testing. Toxicology 2009; 267:14-9. [PMID: 19903508 DOI: 10.1016/j.tox.2009.11.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 10/22/2009] [Accepted: 11/03/2009] [Indexed: 10/20/2022]
Abstract
Toxicological assessment of pharmaceutical and non-pharmaceutical chemicals is a regulatory requirement to ensure all compounds likely to be exposed to humans or the environment are safe. These studies rely on the use of large numbers of animals and involve a number of assumptions and extrapolations that remain controversial in assuring consumer safety. The UK's National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) has taken a collaborative approach to identify opportunities for implementation of the 3Rs principles (Replacement, Reduction and Refinement) to drive innovation and support animal welfare in toxicity testing. This review highlights the mechanisms by which the NC3Rs is working with the pharmaceutical and chemical industries and regulatory authorities to achieve these goals.
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Affiliation(s)
- Anthony M Holmes
- National Centre for the Replacement, Refinement and Reduction of Animals in Research, 20 Park Crescent, London W1B1AL, UK.
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