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Martinez VV, Dutra BAL, Santhiago MR, Wilson SE. Effect of Topical Losartan in the Treatment of Established Corneal Fibrosis in Rabbits. Transl Vis Sci Technol 2024; 13:22. [PMID: 39133495 PMCID: PMC11323991 DOI: 10.1167/tvst.13.8.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 06/08/2024] [Indexed: 08/13/2024] Open
Abstract
Purpose The purpose of this study was to evaluate the safety and efficacy of topical losartan in the therapeutic treatment of established corneal scaring fibrosis at 1 month after alkali burn in rabbits. Methods Standardized alkali burns were performed in 1 eye of 24 rabbits with 0.75N NaOH for 15 seconds. Corneas were allowed to heal and develop scaring of the cornea for 1 month. Twelve eyes per group were treated with 50 µL of topical 0.8 mg/mL losartan in balanced salt solution (BSS), pH 7.0, and 12 eyes were treated with vehicle BSS 6 times per day. Six corneas were analyzed at 1 week or 1 month in each group. Standardized slit lamp photographs were obtained at the end point for each cornea and opacity was quantitated using ImageJ. Corneoscleral rims were cryofixed in optimum cutting temperature (OCT) solution and combined duplex immunohistochemistry for myofibroblast marker alpha-smooth muscle actin (α-SMA), mesenchymal cell marker vimentin, and TUNEL assay for apoptosis was performed on all corneas. Results Topical losartan was effective in the treatment of established stromal fibrosis following alkali burn injury to the rabbit cornea. Stromal myofibroblast density was decreased and stromal cell apoptosis was increased (included both α-SMA-positive myofibroblasts and α-SMA-negative, vimentin-positive cells) at both 1 week and 1 month in the topical losartan-treated compared with vehicle-treated groups. Conclusions Topical losartan is effective in the treatment of established stromal fibrosis in rabbits. Most myofibroblasts disappear from the stroma within the first month of losartan treatment. Longer treatment with topical losartan is needed to allow time for corneal fibroblast regeneration of the epithelial basement membrane (in coordination with epithelial cells) and the removal of disordered extracellular matrix produced by myofibroblasts.
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Affiliation(s)
| | - Barbara Araujo Lima Dutra
- The Cole Eye Institute, The Cleveland Clinic, Cleveland, OH, USA
- Department of Ophthalmology at University of Sao Paulo, Sao Paulo, Brazil
| | | | - Steven E. Wilson
- The Cole Eye Institute, The Cleveland Clinic, Cleveland, OH, USA
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Poole K, Iyer KS, Schmidtke DW, Petroll WM, Varner VD. Corneal keratocytes, fibroblasts, and myofibroblasts exhibit distinct transcriptional profiles in vitro. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.28.582620. [PMID: 38464034 PMCID: PMC10925317 DOI: 10.1101/2024.02.28.582620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Purpose After stromal injury to the cornea, the release of growth factors and pro-inflammatory cytokines promotes the activation of quiescent keratocytes into a migratory fibroblast and/or fibrotic myofibroblast phenotype. Persistence of the myofibroblast phenotype can lead to corneal fibrosis and scarring, which are leading causes of blindness worldwide. This study aims to establish comprehensive transcriptional profiles for cultured corneal keratocytes, fibroblasts, and myofibroblasts to gain insights into the mechanisms through which these phenotypic changes occur. Methods Primary rabbit corneal keratocytes were cultured in either defined serum-free media (SF), fetal bovine serum (FBS) containing media, or in the presence of TGF-β1 to induce keratocyte, fibroblast, or myofibroblast phenotypes, respectively. Bulk RNA sequencing followed by bioinformatic analyses was performed to identify significant differentially expressed genes (DEGs) and enriched biological pathways for each phenotype. Results Genes commonly associated with keratocytes, fibroblasts, or myofibroblasts showed high relative expression in SF, FBS, or TGF-β1 culture conditions, respectively. Differential expression and functional analyses revealed novel DEGs for each cell type, as well as enriched pathways indicative of differences in proliferation, apoptosis, extracellular matrix (ECM) synthesis, cell-ECM interactions, cytokine signaling, and cell mechanics. Conclusions Overall, these data demonstrate distinct transcriptional differences among cultured corneal keratocytes, fibroblasts, and myofibroblasts. We have identified genes and signaling pathways that may play important roles in keratocyte differentiation, including many related to mechanotransduction and ECM biology. Our findings have revealed novel molecular markers for each cell type, as well as possible targets for modulating cell behavior and promoting physiological corneal wound healing.
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Wilson SE. Two-phase mechanism in the treatment of corneal stromal fibrosis with topical losartan. Exp Eye Res 2024; 242:109884. [PMID: 38570181 DOI: 10.1016/j.exer.2024.109884] [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: 02/02/2024] [Revised: 03/12/2024] [Accepted: 03/31/2024] [Indexed: 04/05/2024]
Abstract
Recent studies in rabbits and case reports in humans have demonstrated the efficacy of topical losartan in the treatment of corneal scarring fibrosis after a wide range of injuries, including chemical burns, infections, surgical complications, and some diseases. It is hypothesized that the effect of losartan on the fibrotic corneal stroma occurs through a two-phase process in which losartan first triggers the elimination of myofibroblasts by directing their apoptosis via inhibition of extracellular signal-regulated kinase (ERK)-mediated signal transduction, and possibly through signaling effects on the viability and development of corneal fibroblast and fibrocyte myofibroblast precursor cells. This first step likely occurs within a week or two in most corneas with fibrosis treated with topical losartan, but the medication must be continued for much longer until the epithelial basement membrane (EBM) is fully regenerated or new myofibroblasts will develop from precursor cells. Once the myofibroblasts are eliminated from the fibrotic stroma, corneal fibroblasts can migrate into the fibrotic tissue and reabsorb/reorganize the disordered extracellular matrix (ECM) previously produced by the myofibroblasts. This second stage is longer and more variable in different eyes of rabbits and humans, and accounts for most of the variability in the time it takes for the stromal opacity to be markedly reduced by topical losartan treatment. Eventually, keratocytes reemerge in the previously fibrotic stromal tissue to fine-tune the collagens and other ECM components and maintain the normal structure of the corneal stroma. The efficacy of losartan in the prevention and treatment of corneal fibrosis suggests that it acts as a surrogate for the EBM, by suppressing TGF beta-directed scarring of the wounded corneal stroma, until control over TGF beta action is re-established by a healed EBM, while also supporting regeneration of the EBM by allowing corneal fibroblasts to occupy the subepithelial stroma in the place of myofibroblasts.
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Affiliation(s)
- Steven E Wilson
- Cole Eye Institute, The Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, USA.
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Ni H, Li L, Hu D, Yang M, Wang D, Ma H, Bu W, Yang J, Zhu LE, Zhai D, Song T, Yang S, Lu Q, Li D, Ran J, Liu M. Dynamic changes of endothelial and stromal cilia are required for the maintenance of corneal homeostasis. J Cell Physiol 2024; 239:e31215. [PMID: 38308657 DOI: 10.1002/jcp.31215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/21/2024] [Accepted: 01/24/2024] [Indexed: 02/05/2024]
Abstract
Primary cilia are distributed extensively within the corneal epithelium and endothelium. However, the presence of cilia in the corneal stroma and the dynamic changes and roles of endothelial and stromal cilia in corneal homeostasis remain largely unknown. Here, we present compelling evidence for the presence of primary cilia in the corneal stroma, both in vivo and in vitro. We also demonstrate dynamic changes of both endothelial and stromal cilia during corneal development. In addition, our data show that cryoinjury triggers dramatic cilium formation in the corneal endothelium and stroma. Furthermore, depletion of cilia in mutant mice lacking intraflagellar transport protein 88 compromises the corneal endothelial capacity to establish the effective tissue barrier, leading to an upregulation of α-smooth muscle actin within the corneal stroma in response to cryoinjury. These observations underscore the essential involvement of corneal endothelial and stromal cilia in maintaining corneal homeostasis and provide an innovative strategy for the treatment of corneal injuries and diseases.
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Affiliation(s)
- Hua Ni
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
- College of Life and Geographic Sciences, Kashi University, Kashi, China
| | - Lamei Li
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Die Hu
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Mulin Yang
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Difei Wang
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Hongbo Ma
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Weiwen Bu
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Jia Yang
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Li-E Zhu
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Denghui Zhai
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Ting Song
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Song Yang
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Quanlong Lu
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Dengwen Li
- Department of Genetics and Cell Biology, Haihe Laboratory of Cell Ecosystem, State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Jie Ran
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Min Liu
- Laboratory of Tissue Homeostasis, Haihe Laboratory of Cell Ecosystem, Tianjin, China
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Martinez VV, Dutra BAL, Sampaio LP, Shiju TM, Santhiago MR, Wilson SE. Topical Losartan Inhibition of Myofibroblast Generation in Rabbit Corneas With Acute Incisions. Cornea 2024; 43:00003226-990000000-00464. [PMID: 38277165 PMCID: PMC11272906 DOI: 10.1097/ico.0000000000003476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 12/06/2023] [Indexed: 01/27/2024]
Abstract
PURPOSE The purpose of this study was to study whether deep central corneal incisions close during topical losartan treatment and the effect of topical losartan on myofibroblast generation after incisions in rabbit corneas. METHODS Rabbits (12) had a 0.35-mm deep radial incision from the center of the cornea into the limbus in 1 eye that was approximated with a single 10-0 nylon suture 1 mm inside the limbus. The incision was treated with 50 μL of topical 0.8 mg/mL losartan or 50 μL of balanced salt solution vehicle 6 times per day for 1 month. Standardized slitlamp photographs of the central incisions were analyzed for opacity with ImageJ before euthanasia. Triplex IHC was performed on cryofixed corneas for myofibroblast marker alpha-smooth muscle actin, mesenchymal cell marker vimentin, and basement membrane marker laminin alpha-5. Stromal α-SMA-positive myofibroblasts surrounding the incisions were quantitated with ImageJ. RESULTS Topical losartan compared with vehicle did not affect closure of the radial incisions or the opacity that developed surrounding the incisions at 1 month after injury. Topical losartan compared with vehicle did significantly decrease the average density of stromal myofibroblasts surrounding the incisions. CONCLUSIONS Topical losartan, a known inhibitor of transforming growth factor beta signaling, did not affect closure of deep corneal incisions. Losartan decreased myofibroblast generation surrounding nearly full-thickness radial corneal incisions compared with vehicle. The opacity at the incisions was not significantly affected by losartan-likely because corneal fibroblasts that develop in the stroma adjacent to the incisions were not changed by the losartan compared with the vehicle.
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Affiliation(s)
| | - Barbara Araujo Lima Dutra
- The Cole Eye Institute, The Cleveland Clinic, Cleveland,
Ohio
- Department of Ophthalmology at University of Sao Paulo, Sao
Paulo, Brazil
| | - Lycia Pedral Sampaio
- The Cole Eye Institute, The Cleveland Clinic, Cleveland,
Ohio
- Department of Ophthalmology at University of Sao Paulo, Sao
Paulo, Brazil
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Jeon KI, Kumar A, Callan CL, DeMagistris M, MacRae S, Nehrke K, Huxlin KR. Blocking Mitochondrial Pyruvate Transport Alters Corneal Myofibroblast Phenotype: A New Target for Treating Fibrosis. Invest Ophthalmol Vis Sci 2023; 64:36. [PMID: 37870848 PMCID: PMC10599161 DOI: 10.1167/iovs.64.13.36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 09/21/2023] [Indexed: 10/24/2023] Open
Abstract
Purpose The purpose of this study was to critically test the hypothesis that mitochondrial pyruvate carrier (MPC) function is essential for maintenance of the corneal myofibroblast phenotype in vitro and in vivo. Methods Protein and mRNA for canonical profibrotic markers were assessed in cultured cat corneal myofibroblasts generated via transforming growth factor (TGF)-β1 stimulation and treated with either the thiazolidinedione (TZD) troglitazone or the MPC inhibitor alpha-cyano-beta-(1-phenylindol-3-yl) acrylate (UK-5099). RNA sequencing was used to gain insight into signaling modules related to instructive, permissive, or corollary changes in gene expression following treatment. A feline photorefractive keratectomy (PRK) model of corneal wounding was used to test the efficacy of topical troglitazone at reducing α-smooth muscle actin (SMA)-positive staining when applied 2 to 4 weeks postoperatively, during peak fibrosis. Results Troglitazone caused cultured myofibroblasts to adopt a fibroblast-like phenotype through a noncanonical, peroxisome proliferator-activated receptor (PPAR)-γ-independent mechanism. Direct MPC inhibition using UK-5099 recapitulated this effect, but classic inhibitors of oxidative phosphorylation (OXPHOS) did not. Gene Set Enrichment Analysis (GSEA) of RNA sequencing data converged on energy substrate utilization and the Mitochondrial Permeability Transition pore as key players in myofibroblast maintenance. Finally, troglitazone applied onto an established zone of active fibrosis post-PRK significantly reduced stromal α-SMA expression. Conclusions Our results provide empirical evidence that metabolic remodeling in myofibroblasts creates selective vulnerabilities beyond simply mitochondrial energy production, and that these are critical for maintenance of the myofibroblast phenotype. For the first time, we provide proof-of-concept data showing that this remodeling can be exploited to treat existing corneal fibrosis via inhibition of the MPC.
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Affiliation(s)
- Kye-Im Jeon
- Department of Ophthalmology, Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Ankita Kumar
- Department of Ophthalmology, Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Christine L Callan
- Department of Ophthalmology, Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Margaret DeMagistris
- Department of Ophthalmology, Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Scott MacRae
- Department of Ophthalmology, Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - Keith Nehrke
- Department of Medicine-Nephrology Division, University of Rochester, Rochester, New York, United States
| | - Krystel R Huxlin
- Department of Ophthalmology, Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, New York, United States
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Sampaio LP, Villabona-Martinez V, Shiju TM, Santhiago MR, Wilson SE. Topical Losartan Decreases Myofibroblast Generation But Not Corneal Opacity After Surface Blast-Simulating Irregular PTK in Rabbits. Transl Vis Sci Technol 2023; 12:20. [PMID: 37750746 PMCID: PMC10541722 DOI: 10.1167/tvst.12.9.20] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 09/04/2023] [Indexed: 09/27/2023] Open
Abstract
Purpose To evaluate the efficacy of topical losartan after blast injury-simulating irregular phototherapeutic keratectomy (PTK) in rabbits. Methods Twelve NZW rabbits underwent 100 pulse 6.5 mm diameter PTK over a metal screen to generate severe surface irregularity and inhibit epithelial basement membrane regeneration. Corneas were treated with 0.8 mg/mL losartan in balanced salt solution (BSS) or BSS 50 µL six times per day for six weeks after PTK. All corneas had slit lamp photography, with and without 1% fluorescein at two, four, and six weeks after PTK, and were analyzed using immunohistochemistry for the myofibroblast marker α-smooth muscle actin (α-SMA), keratocyte marker keratocan, mesenchymal cell marker vimentin, transforming growth factor (TGF)-β1, and collagen type IV. Results Topical 0.8 mg/mL losartan six times a day significantly decreased anterior stromal α-SMA intensity units compared to BSS at six weeks after anterior stromal irregularity-inducing screened PTK (P = 0.009). Central corneal opacity, however, was not significantly different between the two groups. Keratocan, vimentin, TGF-β1, or collagen type IV levels in the anterior stroma were not significantly different between the two groups. Conclusions Topical losartan effectively decreased myofibroblast generation after surface blast simulation irregular PTK. However, these results suggest initial masking-smoothing PTK, along with adjuvant topical losartan therapy, may be needed to decrease corneal stromal opacity after traumatic injuries that produce severe surface irregularity. Translational Relevance Topical losartan decreased scar-producing stromal myofibroblasts after irregular PTK over a metal screen but early smoothing of irregularity would also likely be needed to significantly decrease corneal opacity.
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Affiliation(s)
- Lycia Pedral Sampaio
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Ophthalmology at University of Sao Paulo, Sao Paulo, Brazil
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Surovtseva MA, Kim II, Bondarenko NA, Lykov AP, Krasner KY, Chepeleva EV, Bgatova NP, Trunov AN, Chernykh VV, Poveshchenko OV. Derivation of Human Corneal Keratocytes from ReLEx SMILE Lenticules for Cell Therapy and Tissue Engineering. Int J Mol Sci 2023; 24:ijms24108828. [PMID: 37240176 DOI: 10.3390/ijms24108828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/04/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
Fibroblasts isolated and expanded from ReLEx SMILE lenticules can be a source of human keratocytes. Since corneal keratocytes are quiescent cells, it is difficult to expand them in vitro in suitable numbers for clinical and experimental use. In the present study, this problem was solved by isolating and growing corneal fibroblasts (CFs) with a high proliferative potential and their reversion to keratocytes in a selective serum-free medium. Fibroblasts reversed into keratocytes (rCFs) had a dendritic morphology and ultrastructural signs of activation of protein synthesis and metabolism. The cultivation of CFs in a medium with 10% FCS and their reversion into keratocytes was not accompanied by the induction of myofibroblasts. After reversion, the cells spontaneously formed spheroids and expressed keratocan and lumican markers, but not mesenchymal ones. The rCFs had low proliferative and migratory activity, and their conditioned medium contained a low level of VEGF. CF reversion was not accompanied by a change with the levels of IGF-1, TNF-alpha, SDF-1a, and sICAM-1. In the present study, it has been demonstrated that fibroblasts from ReLEx SMILE lenticules reverse into keratocytes in serum-free KGM, maintaining the morphology and functional properties of primary keratocytes. These keratocytes have a potential for tissue engineering and cell therapy of various corneal pathologies.
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Affiliation(s)
- Maria A Surovtseva
- Research Institute of Clinical and Experimental Lymphology-Branch of the Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 2 Timakova Str., 630060 Novosibirsk, Russia
| | - Irina I Kim
- Research Institute of Clinical and Experimental Lymphology-Branch of the Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 2 Timakova Str., 630060 Novosibirsk, Russia
| | - Natalia A Bondarenko
- Research Institute of Clinical and Experimental Lymphology-Branch of the Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 2 Timakova Str., 630060 Novosibirsk, Russia
| | - Alexander P Lykov
- Research Institute of Clinical and Experimental Lymphology-Branch of the Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 2 Timakova Str., 630060 Novosibirsk, Russia
| | - Kristina Yu Krasner
- Research Institute of Clinical and Experimental Lymphology-Branch of the Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 2 Timakova Str., 630060 Novosibirsk, Russia
- Novosibirsk Branch of S. Fedorov Eye Microsurgery Federal State Institution, 10 Kalkhidskaya Str., 630096 Novosibirsk, Russia
| | - Elena V Chepeleva
- Research Institute of Clinical and Experimental Lymphology-Branch of the Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 2 Timakova Str., 630060 Novosibirsk, Russia
| | - Nataliya P Bgatova
- Research Institute of Clinical and Experimental Lymphology-Branch of the Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 2 Timakova Str., 630060 Novosibirsk, Russia
| | - Alexander N Trunov
- Novosibirsk Branch of S. Fedorov Eye Microsurgery Federal State Institution, 10 Kalkhidskaya Str., 630096 Novosibirsk, Russia
| | - Valery V Chernykh
- Novosibirsk Branch of S. Fedorov Eye Microsurgery Federal State Institution, 10 Kalkhidskaya Str., 630096 Novosibirsk, Russia
| | - Olga V Poveshchenko
- Research Institute of Clinical and Experimental Lymphology-Branch of the Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, 2 Timakova Str., 630060 Novosibirsk, Russia
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Sprogyte L, Park M, Di Girolamo N. Pathogenesis of Alkali Injury-Induced Limbal Stem Cell Deficiency: A Literature Survey of Animal Models. Cells 2023; 12:cells12091294. [PMID: 37174694 PMCID: PMC10177508 DOI: 10.3390/cells12091294] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/28/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
Limbal stem cell deficiency (LSCD) is a debilitating ocular surface disease that eventuates from a depleted or dysfunctional limbal epithelial stem cell (LESC) pool, resulting in corneal epithelial failure and blindness. The leading cause of LSCD is a chemical burn, with alkali substances being the most common inciting agents. Characteristic features of alkali-induced LSCD include corneal conjunctivalization, inflammation, neovascularization and fibrosis. Over the past decades, animal models of corneal alkali burn and alkali-induced LSCD have been instrumental in improving our understanding of the pathophysiological mechanisms responsible for disease development. Through these paradigms, important insights have been gained with regards to signaling pathways that drive inflammation, neovascularization and fibrosis, including NF-κB, ERK, p38 MAPK, JNK, STAT3, PI3K/AKT, mTOR and WNT/β-catenin cascades. Nonetheless, the molecular and cellular events that underpin re-epithelialization and those that govern long-term epithelial behavior are poorly understood. This review provides an overview of the current mechanistic insights into the pathophysiology of alkali-induced LSCD. Moreover, we highlight limitations regarding existing animal models and knowledge gaps which, if addressed, would facilitate development of more efficacious therapeutic strategies for patients with alkali-induced LSCD.
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Affiliation(s)
- Lina Sprogyte
- Mechanisms of Disease and Translational Research, School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia
| | - Mijeong Park
- Mechanisms of Disease and Translational Research, School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia
| | - Nick Di Girolamo
- Mechanisms of Disease and Translational Research, School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia
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Wilson SE. The Cornea: No Difference in the Wound Healing Response to Injury Related to Whether, or Not, There's a Bowman's Layer. Biomolecules 2023; 13:biom13050771. [PMID: 37238641 DOI: 10.3390/biom13050771] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/10/2023] [Accepted: 04/16/2023] [Indexed: 05/28/2023] Open
Abstract
Bowman's layer is an acellular layer in the anterior stroma found in the corneas of humans, most other primates, chickens, and some other species. Many other species, however, including the rabbit, dog, wolf, cat, tiger, and lion, do not have a Bowman's layer. Millions of humans who have had photorefractive keratectomy over the past thirty plus years have had Bowman's layer removed by excimer laser ablation over their central cornea without apparent sequelae. A prior study showed that Bowman's layer does not contribute significantly to mechanical stability within the cornea. Bowman's layer does not have a barrier function, as many cytokines and growth factors, as well as other molecules, such as EBM component perlecan, pass bidirectionally through Bowman's layer in normal corneal functions, and during the response to epithelial scrape injury. We hypothesized that Bowman's layer represents a visible indicator of ongoing cytokine and growth factor-mediated interactions that occur between corneal epithelial cells (and corneal endothelial cells) and stromal keratocytes that maintain the normal corneal tissue organization via negative chemotactic and apoptotic effects of modulators produced by the epithelium on stromal keratocytes. Interleukin-1 alpha, produced constitutively by corneal epithelial cells and endothelial cells, is thought to be one of these cytokines. Bowman's layer is destroyed in corneas with advanced Fuchs' dystrophy or pseudophakic bullous keratopathy when the epithelium becomes edematous and dysfunctional, and fibrovascular tissue commonly develops beneath and/or within the epithelium in these corneas. Bowman's-like layers have been noted to develop surrounding epithelial plugs within the stromal incisions years after radial keratotomy. Although there are species-related differences in corneal wound healing, and even between strains within a species, these differences are not related to the presence or absence of Bowman's layer.
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Affiliation(s)
- Steven E Wilson
- The Cole Eye Institute, I-32, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
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