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Ergen SK, Subasi S, Rencber SF, Duruksu G, Yazir Y. Evaluation of clinical and histological effects of KGF-2 and NGF on corneal wound healing in an experimental alkali burn rabbit model. Exp Eye Res 2022; 223:109190. [PMID: 35963307 DOI: 10.1016/j.exer.2022.109190] [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: 05/06/2022] [Revised: 07/02/2022] [Accepted: 07/07/2022] [Indexed: 11/04/2022]
Abstract
Endogenously produced peptide growth factors such as keratinocyte growth factor-2 (KGF-2) and nerve growth factor (NGF) play a key role in the natural corneal wound healing process. However, this self-healing ability of the corneal tissue is often impaired in cases of severe corneal damage, as in corneal alkali injuries. In the present study, we investigated the clinical and histopathological effects of topical recombinant human keratinocyte growth factor-2 and nerve growth factor treatments in a rabbit model of corneal alkali burn. After induction of an alkali burn, 24 rabbits were divided equally into three groups: control group, KGF-2 group, and NGF group. Clinical parameters including epithelial healing, opacification, neovascularization and central corneal thickness were evaluated on the first (D1), seventh (D7) and fourteenth (D14) days after injury. Corneal histology was performed using hematoxylin/eosin (H&E) and Masson's Trichrome stains. Immunohistochemical staining for matrix metalloproteinase-2 (MMP-2), MMP-9 and transforming growth factor-β (TGF-β) was performed. On D14, the percentage of epithelial defect and opacity were significantly less in the KGF-2 and NGF groups compared to the control group (p < 0.05). There was no significant difference between the groups in central corneal thickness. In the evaluation of neovascularization on D14, the NGF group was significantly less vascularized than the control group (p = 0.011). Histological examination showed a significant increase in stromal edema and inflammation in the control group compared to both treatment groups (p < 0.05). There was also a significant difference between the NGF and control groups in histological evaluation of epithelial repair and vascularization (p < 0.05). When immunoreactivity of MMP-2, MMP-9 and TGF-β was examined, there was a significant increase in the control group compared to the NGF group (p < 0.05). Taken together, both NGF and KGF-2 treatments were effective for early re-epithelialization and decrease in inflammation, opacity and neovascularization after corneal alkali burn. The inhibitory effect of NGF treatment on chemical-induced neovascularization was found to be superior to KGF-2 treatment.
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Affiliation(s)
- Sebnem Kaya Ergen
- Department of Ophthalmology, Karamürsel State Hospital, Kocaeli, Turkey.
| | - Sevgi Subasi
- Department of Ophthalmology, Kocaeli University Faculty of Medicine, Kocaeli, Turkey
| | - Selenay Furat Rencber
- Department of Histology and Embryology, Kocaeli University Faculty of Medicine, Kocaeli, Turkey
| | - Gökhan Duruksu
- Stem Cell and Gene Therapies Research and Applied Center, Kocaeli University, Kocaeli, Turkey
| | - Yusufhan Yazir
- Department of Histology and Embryology, Kocaeli University Faculty of Medicine, Kocaeli, Turkey; Stem Cell and Gene Therapies Research and Applied Center, Kocaeli University, Kocaeli, Turkey
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Sustained release of decorin to the surface of the eye enables scarless corneal regeneration. NPJ Regen Med 2018; 3:23. [PMID: 30588331 PMCID: PMC6303295 DOI: 10.1038/s41536-018-0061-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 11/15/2018] [Indexed: 11/25/2022] Open
Abstract
Disorganization of the transparent collagenous matrix in the cornea, as a consequence of a variety of infections and inflammatory conditions, leads to corneal opacity and sight-loss. Such corneal opacities are a leading cause of blindness, according to the WHO. Public health programs target prevention of corneal scarring, but the only curative treatment of established scarring is through transplantation. Although attempts to minimize corneal scarring through aggressive control of infection and inflammation are made, there has been little progress in the development of anti-scarring therapies. This is owing to eye drop formulations using low viscosity or weak gelling materials having short retention times on the ocular surface. In this study, we report an innovative eye drop formulation that has the ability to provide sustained delivery of decorin, an anti-scarring agent. The novelty of this eye drop lies in the method of structuring during manufacture, which creates a material that can transition between solid and liquid states, allowing retention in a dynamic environment being slowly removed through blinking. In a murine model of Pseudomonaskeratitis, applying the eye drop resulted in reductions of corneal opacity within 16 days. More remarkably, the addition of hrDecorin resulted in restoration of corneal epithelial integrity with minimal stromal opacity endorsed by reduced α-smooth muscle actin (αSMA), fibronectin, and laminin levels. We believe that this drug delivery system is an ideal non-invasive anti-fibrotic treatment for patients with microbial keratitis, potentially without recourse to surgery, saving the sight of many in the developing world, where corneal transplantation may not be available. An eye drop formulation that applies anti-scarring drugs to the surface of the eye helps reverse infection-induced corneal damage in mice. Hill et al. from the University of Birmingham, UK, formulated a fluid gel loaded with a wound-healing protein called decorin that conforms to the ocular surface and is cleared gradually through blinking. With colleagues in California, they applied the therapeutic eye drop to mice with bacterial eye infections that trigger sight-threatening corneal scarring. Within a matter of days, the team saw improvements in corneal transparency, with reductions in scar tissue and reconstitution of healthy cells. Such a drug delivery system, if successful in humans, could help save many people’s sight and reduce the need for corneal transplantation.
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Abstract
Myofibroblasts are activated in response to tissue injury with the primary task to repair lost or damaged extracellular matrix. Enhanced collagen secretion and subsequent contraction - scarring - are part of the normal wound healing response and crucial to restore tissue integrity. Due to myofibroblasts ability to repair but not regenerate, accumulation of scar tissue is always associated with reduced organ performance. This is a fair price to pay by the body for not falling apart. Whereas myofibroblasts typically vanish after successful repair, dysregulation of the normal repair process can lead to persistent myofibroblast activation, for instance by chronic inflammation or mechanical stress in the tissue. Excessive repair leads to the accumulation of stiff collagenous ECM contractures - fibrosis - with dramatic consequences for organ function. The clinical need to terminate detrimental myofibroblast activities has stimulated researchers to answer a number of essential questions: where do myofibroblasts come from, what are the factors leading to their activation, how do we discriminate myofibroblasts from other cells, what is the molecular basis for their contractile activity, and how can we stop or at least control them? This article reviews the current state of the myofibroblast literature by emphasizing their role in ocular repair and fibrosis. It appears that although the eye is quite an extraordinary organ, ocular myofibroblasts behave or misbehave just like their siblings in other organs.
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Affiliation(s)
- Boris Hinz
- Laboratory of Tissue Repair and Regeneration, Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, 150 College Street, FitzGerald Building, Room 234, Toronto, M5S 3E2 Ontario, Canada.
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Koulikovska M, Szymanowski O, Lagali N, Fagerholm P. Platelet-Rich Plasma Prolongs Myofibroblast Accumulation in Corneal Stroma with Incisional Wound. Curr Eye Res 2015; 40:1102-10. [PMID: 25848678 DOI: 10.3109/02713683.2014.978478] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE The purpose of this study was to determine whether platelet-rich plasma (PRP) has an effect on corneal stromal cells in a rat model of wound healing following corneal incision. MATERIALS AND METHODS The effect of PRP on corneal wound healing in vivo was investigated in a corneal incision wound model in rats. 40 rats were wounded by deep corneal incision, and treated with either topically administered PRP (20 rats) or sodium chloride (20 rats). At 4 h and 1, 3, and 5 days after incision, α-smooth muscle actin (α SMA), SMAD2 and SMAD3 expression and apoptosis in stromal cells were evaluated by immunohistochemistry, and IL-1β mRNA expression was evaluated by real time PCR. RESULTS PRP-treated corneas exhibited reduced stromal cell apoptosis at day 3 and day 5 (p = 0.038, and <0.001, respectively) relative to controls. Interleukin-1β mRNA expression, however, was unchanged in PRP-treated corneas relative to controls. Topical PRP treatment resulted in a higher proportion of αSMA-positive myofibroblasts recruited to the wound site relative to control corneas. PRP did not affect activation of SMAD2 but activation of SMAD3 was significantly reduced at day 1 (p = 0.001) and dramatically increased at day 5 (p = 0.032). CONCLUSIONS PRP treatment resulted in suppressed stromal cell apoptosis followed by SMAD3 activation and a greater proportion of myofibroblasts present at the wound site. Suppression of stromal cell apoptosis after corneal wounding by use of a growth factor-rich formulation may lead to myofibroblast accumulation by modulation of the TGF-β pathway.
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Affiliation(s)
- Marina Koulikovska
- a Division of Ophthalmology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences , Linköping University , Linköping , Sweden and
| | - Olena Szymanowski
- a Division of Ophthalmology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences , Linköping University , Linköping , Sweden and
| | - Neil Lagali
- a Division of Ophthalmology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences , Linköping University , Linköping , Sweden and.,b Division of Cell Biology, Department of Clinical and Experimental Medicine , Integrative Regenerative Medicine Centre (IGEN), Linköping University , Linköping , Sweden
| | - Per Fagerholm
- a Division of Ophthalmology, Department of Clinical and Experimental Medicine, Faculty of Health Sciences , Linköping University , Linköping , Sweden and.,b Division of Cell Biology, Department of Clinical and Experimental Medicine , Integrative Regenerative Medicine Centre (IGEN), Linköping University , Linköping , Sweden
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Fink MK, Giuliano EA, Tandon A, Mohan RR. Therapeutic potential of Pirfenidone for treating equine corneal scarring. Vet Ophthalmol 2014; 18:242-50. [PMID: 25041235 DOI: 10.1111/vop.12194] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To evaluate the safety and efficacy of Pirfenidone (PFD) in the treatment of equine corneal fibrosis using an in vitro model. METHODS Healthy donor equine corneas were collected and used to generate primary equine corneal fibroblasts (ECFs) by growing cultures in minimal essential medium supplemented with 10% fetal bovine serum. Equine corneal myofibroblasts (ECMs), used as a model of equine corneal fibrosis, were produced by growing ECF cultures in serum-free medium containing transforming growth factor β1 (1 ng/mL). Trypan blue viability assays and changes in ECF morphology were utilized to determine the optimal PFD dose for this in vitro model. Trypan blue viability, phase-contrast microscopy, and TUNEL assays were used to evaluate the cytotoxicity of PFD. Scratch and MTT assays were used to evaluate the effect of PFD on cellular migration and proliferation. Real-time PCR, immunoblot analysis, and immunocytochemistry were employed to determine the efficacy of PFD to inhibit ECM formation in vitro. RESULTS Topical PFD application at 200 μg/mL successfully decreased αSMA expression when compared to the TGFβ1 only treatment group (P < 0.01). PFD application ≤ 200 μg/mL did not affect ECF phenotype or cellular viability and did not result in significant cytotoxicity. CONCLUSIONS Pirfenidone safely and effectively inhibits TGFβ1-induced equine corneal fibrosis in vitro. In vivo studies are warranted.
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Affiliation(s)
- Michael K Fink
- Harry S. Truman Memorial Veterans Hospital, Columbia, MO, USA; College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
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Abstract
Corneal wound healing is a complex process: its mechanisms and the underlying genetic control are not fully understood. It involves the integrated actions of multiple growth factors, cytokines and proteases produced by epithelial cells, stromal keratocytes, inflammatory cells and lacrimal gland cells. Following an epithelial insult, multiple cytokines are released triggering a cascade of events that leads to repair the epithelial defect and remodelling of the stroma to minimize the loss of transparency and function. In this review, we examine the literature surrounding the genomics of corneal wound healing with respect to the following topics: epithelial and stromal wound healing (including inhibition); corneal neovascularisation; the role of corneal nerves in wound healing; the endothelium; the role of aquaporins and aptamers. We also examine the effect of ectasia on corneal wound healing with regard to keratoconus and following corneal surgery. A better understanding of the cellular and molecular changes that occur during repair of corneal wounds will provide the opportunity to design treatments that selectively modulate key phases of the healing process resulting in scars that more closely resemble normal corneal architecture.
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Affiliation(s)
- Nick J R Maycock
- Eye Department, Queen Alexandra Hospital, Portsmouth, UKNational Institute for Health Research (NIHR), Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
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Anitua E, Muruzabal F, Alcalde I, Merayo-Lloves J, Orive G. Plasma rich in growth factors (PRGF-Endoret) stimulates corneal wound healing and reduces haze formation after PRK surgery. Exp Eye Res 2013; 115:153-61. [DOI: 10.1016/j.exer.2013.07.007] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 06/19/2013] [Accepted: 07/09/2013] [Indexed: 11/26/2022]
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Fan Q, Zhou X, Khor CC, Cheng CY, Goh LK, Sim X, Tay WT, Li YJ, Ong RTH, Suo C, Cornes B, Ikram MK, Chia KS, Seielstad M, Liu J, Vithana E, Young TL, Tai ES, Wong TY, Aung T, Teo YY, Saw SM. Genome-wide meta-analysis of five Asian cohorts identifies PDGFRA as a susceptibility locus for corneal astigmatism. PLoS Genet 2011; 7:e1002402. [PMID: 22144915 PMCID: PMC3228826 DOI: 10.1371/journal.pgen.1002402] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 10/17/2011] [Indexed: 12/21/2022] Open
Abstract
Corneal astigmatism refers to refractive abnormalities and irregularities in the curvature of the cornea, and this interferes with light being accurately focused at a single point in the eye. This ametropic condition is highly prevalent, influences visual acuity, and is a highly heritable trait. There is currently a paucity of research in the genetic etiology of corneal astigmatism. Here we report the results from five genome-wide association studies of corneal astigmatism across three Asian populations, with an initial discovery set of 4,254 Chinese and Malay individuals consisting of 2,249 cases and 2,005 controls. Replication was obtained from three surveys comprising of 2,139 Indians, an additional 929 Chinese children, and an independent 397 Chinese family trios. Variants in PDGFRA on chromosome 4q12 (lead SNP: rs7677751, allelic odds ratio = 1.26 (95% CI: 1.16-1.36), P(meta) = 7.87×10(-9)) were identified to be significantly associated with corneal astigmatism, exhibiting consistent effect sizes across all five cohorts. This highlights the potential role of variants in PDGFRA in the genetic etiology of corneal astigmatism across diverse Asian populations.
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Affiliation(s)
- Qiao Fan
- School of Public Health, National University of Singapore, Singapore, Singapore
| | - Xin Zhou
- School of Public Health, National University of Singapore, Singapore, Singapore
| | - Chiea-Chuen Khor
- Genome Institute of Singapore, Agency for Science, Technology, and Research, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Centre for Molecular Epidemiology, National University of Singapore, Singapore, Singapore
- Department of Pediatrics, National University of Singapore, Singapore, Singapore
| | - Ching-Yu Cheng
- School of Public Health, National University of Singapore, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Department of Ophthalmology, National University of Singapore, Singapore, Singapore
| | - Liang-Kee Goh
- School of Public Health, National University of Singapore, Singapore, Singapore
- Duke–National University of Singapore Graduate Medical School, Singapore, Singapore
- Department of Medical Oncology, National Cancer Centre Singapore, Singapore, Singapore
| | - Xueling Sim
- Centre for Molecular Epidemiology, National University of Singapore, Singapore, Singapore
| | - Wan-Ting Tay
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Yi-Ju Li
- Center for Human Genetics, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Rick Twee-Hee Ong
- School of Public Health, National University of Singapore, Singapore, Singapore
- NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Chen Suo
- Centre for Molecular Epidemiology, National University of Singapore, Singapore, Singapore
| | - Belinda Cornes
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Mohammad Kamran Ikram
- School of Public Health, National University of Singapore, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Duke–National University of Singapore Graduate Medical School, Singapore, Singapore
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Kee-Seng Chia
- School of Public Health, National University of Singapore, Singapore, Singapore
- Centre for Molecular Epidemiology, National University of Singapore, Singapore, Singapore
- NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Mark Seielstad
- Institute for Human Genetics and Department of Laboratory Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Jianjun Liu
- Genome Institute of Singapore, Agency for Science, Technology, and Research, Singapore, Singapore
| | - Eranga Vithana
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Department of Ophthalmology, National University of Singapore, Singapore, Singapore
| | - Terri L. Young
- Center for Human Genetics, Duke University Medical Center, Durham, North Carolina, United States of America
| | - E.-Shyong Tai
- School of Public Health, National University of Singapore, Singapore, Singapore
- Department of Medicine, National University of Singapore, Singapore, Singapore
| | - Tien-Yin Wong
- School of Public Health, National University of Singapore, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Department of Ophthalmology, National University of Singapore, Singapore, Singapore
- Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia
| | - Tin Aung
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Department of Ophthalmology, National University of Singapore, Singapore, Singapore
| | - Yik-Ying Teo
- School of Public Health, National University of Singapore, Singapore, Singapore
- Genome Institute of Singapore, Agency for Science, Technology, and Research, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore, Singapore
- Department of Statistics and Applied Probability, National University of Singapore, Singapore, Singapore
| | - Seang-Mei Saw
- School of Public Health, National University of Singapore, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Department of Ophthalmology, National University of Singapore, Singapore, Singapore
- NUS Graduate School for Integrative Science and Engineering, National University of Singapore, Singapore, Singapore
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Harvey SAK, Guerriero E, Charukamnoetkanok N, Piluek J, Schuman JS, Sundarraj N. Responses of cultured human keratocytes and myofibroblasts to ethyl pyruvate: a microarray analysis of gene expression. Invest Ophthalmol Vis Sci 2010; 51:2917-27. [PMID: 20053976 DOI: 10.1167/iovs.09-4498] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Ethyl pyruvate (EP) has pharmacologic effects that remediate cellular stress. In the organ-cultured murine lens, EP ameliorates oxidative stress, and in a rat cataract model, it attenuates cataract formation. However, corneal responses to EP have not been elucidated. In this study, the potential of EP as a therapeutic agent in corneal wound healing was determined by examining its effects on the transition of quiescent corneal stromal keratocytes into contractile myofibroblasts. METHODS Three independent preparations of cultured human keratocytes were treated with TGF-beta1, to elicit a phenotypic transition to myofibroblasts in the presence or absence of 10 or 15 mM EP. Gene expression profiles of the 12 samples (keratocytes +/- EP +/- TGF-beta1 for three preparations) were produced by using gene microarrays. RESULTS TGF-beta1-driven twofold changes in at least two of three experiments defined a group of 1961 genes. Genes showing twofold modulation by EP in at least two experiments appeared exclusively in myofibroblasts (857 genes), exclusively in keratocytes (409 genes), or in both phenotypes (252 genes). Analysis of these three EP-modulated groups showed that EP (1) inhibited myofibroblast proliferation with concomitant modulation of some cell cycle genes, (2) augmented the NRF2-mediated antioxidant response in both keratocytes and myofibroblasts, and (3) modified the TGF-beta1-driven transition of keratocytes to myofibroblasts by inhibiting the upregulation of a subset of profibrotic genes. CONCLUSIONS These EP-induced phenotypic changes in myofibroblasts indicate the potential of EP as a therapeutic agent in corneal wound healing.
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Affiliation(s)
- Stephen A K Harvey
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213-2588, USA.
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Yu FSX, Yin J, Xu K, Huang J. Growth factors and corneal epithelial wound healing. Brain Res Bull 2009; 81:229-35. [PMID: 19733636 DOI: 10.1016/j.brainresbull.2009.08.024] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 08/19/2009] [Accepted: 08/26/2009] [Indexed: 10/20/2022]
Abstract
In this article, we briefly review recent findings in the effects of growth factors including the EGF family, KGF, HGF, IGF, insulin, and TGF-beta on corneal epithelial wound healing. We discuss the essential role of EGFR in inter-receptor cross-talk in response to wounding in corneal epithelium and bring forward a concept of "alarmins" to the field of wound healing research.
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Affiliation(s)
- Fu-Shin X Yu
- Kresge Eye Institute, Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, 4717 St. Antoine Blvd., Detroit, MI, 48201, USA.
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Xing D, Bonanno JA. Effect of cAMP on TGFbeta1-induced corneal keratocyte-myofibroblast transformation. Invest Ophthalmol Vis Sci 2008; 50:626-33. [PMID: 18936144 DOI: 10.1167/iovs.08-2444] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
PURPOSE TGFbeta is the major mediator to induce myofibroblast differentiation in the corneal wound-healing process. Elevated cAMP can reduce TGFbeta-induced fibrosis in other tissues. This study was conducted to determine whether elevated cAMP can inhibit TGFbeta1-induced rabbit corneal keratocyte-myofibroblast transformation. METHODS Primary isolated rabbit corneal keratocytes were cultured in serum-free medium. The effects of the adenylate cyclase agonist forskolin (FSK; 2 microM) on TGFbeta1 (5 ng/mL)-induced alpha-smooth muscle actin (alpha-SMA) expression was examined by immunofluorescence, flow cytometry, and immunochemistry 72 hours after treatment. The effects of TGFbeta+FSK on activated pSmad3, CREB binding protein (CBP), MAPKs, and RhoA were determined by coimmunoprecipitation and Western blot. RESULTS FSK significantly reduced the myofibroblast phenotype and alpha-SMA expression induced by TGFbeta1 in rabbit corneal keratocytes. TGFbeta1 increased the phosphorylation of ERK and Smad3. TGFbeta1-induced alpha-SMA expression was reduced by MEK inhibition (U0126); however, the levels of pERK, pSmad3, or the extent of the interaction between pSmad3 and CBP induced by TGFbeta1 were not affected by FSK. TGFbeta1 also activated RhoA and ROCK (Y27632) inhibition reduced alpha-SMA expression. Activation of RhoA was significantly reduced by FSK. CONCLUSIONS Raising cAMP by FSK treatment inhibits the TGFbeta1-induced corneal myofibroblast transformation and alpha-SMA expression and thereby provides a promising method to control corneal fibrosis. The data suggest that cAMP-dependent inhibition does not occur by altering Smads or MAPK signaling, but possibly by reducing the activation of RhoA.
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Affiliation(s)
- Dongmei Xing
- School of Optometry, Indiana University, Bloomington, Indiana 47405, USA
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Farid M, Morishige N, Lam L, Wahlert A, Steinert RF, Jester JV. Detection of corneal fibrosis by imaging second harmonic-generated signals in rabbit corneas treated with mitomycin C after excimer laser surface ablation. Invest Ophthalmol Vis Sci 2008; 49:4377-83. [PMID: 18502995 DOI: 10.1167/iovs.08-1983] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Recent studies have shown that confocal imaging of second harmonic-generated (SHG) signals can detect corneal collagen organization. The purpose of this study was to assess whether SHG signals can detect differences in corneal fibrosis after excimer laser surface ablation (photorefractive keratectomy [PRK]). METHODS Rabbits received 9-D PRK in one eye followed by treatment with either mitomycin C (MMC) or vehicle. Corneal haze was measured by in vivo confocal microscopy before and 2, 4, 8, and 12 weeks after surgery. Animals were then killed and corneas were evaluated by visible and nonlinear confocal microscopy. RESULTS PRK induced significant haze in vehicle-treated corneas that peaked at 2 weeks and remained elevated at 12 weeks after surgery. MMC treatment significantly (P < 0.05) reduced corneal haze at 2 weeks and was essentially normal by 12 weeks. Imaging of SHG signals in vehicle-treated eyes showed an anterior layer of collagen forming a honeycomb network blending into a dense mat of irregularly arranged collagen fibers that overlaid normal orthogonally arranged collagen lamellae. MMC treatment showed normal collagen organization at the surface. Fibrotic tissue was associated with a high cell density and alignment of intracellular actin filaments with collagen fiber bundles. In MMC-treated eyes, an anterior acellular zone overlaid a sparsely populated stroma containing isolated and enlarged keratocytes. CONCLUSIONS Imaging of SHG signals provides a sensitive means for detection of corneal fibrosis after surface ablation and can be used to assess the effects of antifibrotic therapy on corneal healing after refractive surgery.
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Affiliation(s)
- Marjan Farid
- Gavin S Herbert Eye Institute, University of California, Irvine Medical Center, Orange, California 92868, USA
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Anti-transforming growth factor beta as a treatment for laryngotracheal stenosis in a canine model. Laryngoscope 2008; 118:546-51. [PMID: 18176351 DOI: 10.1097/mlg.0b013e31815daf6e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES/HYPOTHESIS Laryngotracheal stenosis (LTS) represents a significant treatment dilemma faced by otolaryngologists. Recent topical use of Mitomycin C as an adjunctive treatment has proved helpful but does not completely prevent stenosis. Current literature suggests that transforming growth factor beta (TGFB) plays a significant role in the development of subglottic stenosis. We modified an existing canine model to test antitransforming growth factor beta (anti-TGFB) as a possible treatment for laryngotracheal stenosis. STUDY DESIGN Pilot study in a modified canine model. METHODS Eight mixed-breed dogs underwent cautery injury to the subglottic region creating subsequent laryngotracheal stenosis. Four dogs were treated with saline injection into the injury site and four dogs were treated with a combination of intravenous (5 mg/kg on day 0 and 5 of the experiment) and local injection of anti-TGFB (50 micrograms). RESULTS In the canine model of induced subglottic airway injury, a combination of intralesional and intravenous anti-TGFB results in a reduction in tracheal stenosis (P < .05) and an increase in survival time (P < .03) when compared to the saline control subjects. CONCLUSIONS Anti-TGFB appears to be a useful adjunct in the treatment of LTS. Further study regarding the optimal dosing, route of administration, and timing of delivery is needed to understand the role of anti-TGFB in the treatment for laryngotracheal stenosis.
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Lee JJ, Kim MK, Shin KS, Shin MS, Wee WR, Lee JH. Transforming growth factor-β expression in rat eyes with mechanical debridement of corneal epithelium or epithelial flap. J Cataract Refract Surg 2008; 34:662-9. [DOI: 10.1016/j.jcrs.2007.12.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2007] [Accepted: 12/07/2007] [Indexed: 10/22/2022]
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Bernstein AM, Twining SS, Warejcka DJ, Tall E, Masur SK. Urokinase receptor cleavage: a crucial step in fibroblast-to-myofibroblast differentiation. Mol Biol Cell 2007; 18:2716-27. [PMID: 17507651 PMCID: PMC1924808 DOI: 10.1091/mbc.e06-10-0912] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Revised: 04/24/2007] [Accepted: 05/03/2007] [Indexed: 01/20/2023] Open
Abstract
Fibroblasts migrate into and repopulate connective tissue wounds. At the wound edge, fibroblasts differentiate into myofibroblasts, and they promote wound closure. Regulated fibroblast-to-myofibroblast differentiation is critical for regenerative healing. Previous studies have focused on the role in fibroblasts of urokinase plasmingen activator/urokinase plasmingen activator receptor (uPA/uPAR), an extracellular protease system that promotes matrix remodeling, growth factor activation, and cell migration. Whereas fibroblasts have substantial uPA activity and uPAR expression, we discovered that cultured myofibroblasts eventually lost cell surface uPA/uPAR. This led us to investigate the relevance of uPA/uPAR activity to myofibroblast differentiation. We found that fibroblasts expressed increased amounts of full-length cell surface uPAR (D1D2D3) compared with myofibroblasts, which had reduced expression of D1D2D3 but increased expression of the truncated form of uPAR (D2D3) on their cell surface. Retaining full-length uPAR was found to be essential for regulating myofibroblast differentiation, because 1) protease inhibitors that prevented uPAR cleavage also prevented myofibroblast differentiation, and 2) overexpression of cDNA for a noncleavable form of uPAR inhibited myofibroblast differentiation. These data support a novel hypothesis that maintaining full-length uPAR on the cell surface regulates the fibroblast to myofibroblast transition and that down-regulation of uPAR is necessary for myofibroblast differentiation.
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Affiliation(s)
- Audrey M Bernstein
- Departments of Ophthalmology, Mount Sinai School of Medicine, New York, NY 10029, USA.
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16
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Netto MV, Chalita MR, Krueger RR. Corneal Haze Following PRK With Mitomycin C as a Retreatment Versus Prophylactic Use in the Contralateral Eye. J Refract Surg 2007; 23:96-8. [PMID: 17269251 DOI: 10.3928/1081-597x-20070101-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To report photorefractive keratectomy (PRK) treated with mitomycin C (MMC) for previous corneal haze in one eye and PRK with MMC to prevent corneal haze formation in the fellow eye. METHODS A 40-year-old woman underwent PRK with MMC to treat previous corneal haze (secondary to previous PRK without MMC) for residual refractive error of +0.50 +0.25 x 165 in the left eye and PRK with MMC to prevent corneal haze in the right eye. RESULTS Postoperative slit-lamp examination revealed no haze in the right eye, but continued mild haze in the left eye. CONCLUSIONS Treatment with PRK and MMC for previous corneal haze is not as effective as primary PRK with MMC in preventing postoperative corneal haze formation.
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Affiliation(s)
- Marcelo V Netto
- Cole Eye Institute, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA
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17
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Long Q, Chu R, Zhou X, Dai J, Chen C, Rao SK, Lam DSC. Correlation Between TGF-β1 in Tears and Corneal Haze Following LASEK and Epi-LASIK. J Refract Surg 2006; 22:708-12. [PMID: 16995554 DOI: 10.3928/1081-597x-20060901-13] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare the incidence and degree of corneal haze formation following laser subepithelial keratomileusis (LASEK) and epithelial laser in situ keratomileusis (epi-LASIK), and examine its correlation with tear film transforming growth factor-beta1 (TGF-beta1) levels. METHODS This prospective, interventional, clinical trial included 20 eyes (20 patients) randomly assigned to undergo LASEK or epi-LASIK. The level of TGF-beta1 in tear fluid was measured preoperatively and 1, 3, and 5 days postoperatively. Corneal haze was graded at 1 and 3 months after surgery, and the relationship with TGF-beta1 levels was determined. RESULTS Mean preoperative spherical equivalent refraction was -4.50 +/- 1.44 diopters (D) (range: -1.50 to -6.00 D) for LASEK eyes and -4.90 +/- 1.26 D (range: -1.75 to -6.00 D) for epi-LASIK eyes. Although mean corneal haze scores at 1 month were significantly higher in LASEK-treated eyes than in epi-LASIK treated eyes (P=.031), these scores were similar at 3 months (P=.608). Tear fluid TGF-beta1 levels were similar in LASEK and epi-LASIK eyes before surgery (P=.458) and significantly higher in the LASEK group at 1, 3, and 5 days postoperatively (P=.015, P=.023, and P=.039, respectively). A positive correlation was noted between tear TGF-beta1 levels on the first postoperative day and the degree of corneal haze at 1 month (r=0.501, P=.016). CONCLUSIONS Less corneal haze was noted after epi-LASIK than LASEK. A positive correlation between corneal haze and tear fluid TGF-beta1 levels on the first postoperative day suggest a possible mechanism for the observed difference.
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Affiliation(s)
- Qin Long
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academic of Medical Science, Medical College, Peking, China
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18
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Netto MV, Mohan RR, Sinha S, Sharma A, Gupta PC, Wilson SE. Effect of Prophylactic and Therapeutic Mitomycin C on Corneal Apoptosis, Cellular Proliferation, Haze, and Long-term Keratocyte Density in Rabbits. J Refract Surg 2006; 22:562-74. [PMID: 16805119 PMCID: PMC2756017 DOI: 10.3928/1081-597x-20060601-08] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To determine the mechanism through which topical mitomycin C prevents and treats corneal haze after photorefractive keratectomy (PRK) and to examine the effects of dosage and duration of exposure. METHODS In 224 New Zealand rabbits, -9.0 diopter PRK with mitomycin C or balanced salt solution was performed. Haze level was graded at the slit-lamp. Rabbits were sacrificed at 4 hours, 24 hours, 4 weeks, or 6 months after surgery and immunohistochemistry was performed with TUNEL assay, Ki67, and alpha-SMA. RESULTS TUNEL-positive apoptotic cells marginally increased in all mitomycin C groups whereas Ki67-positive mitotic cells decreased significantly following mitomycin C application. A greater decrease in myofibroblasts was noted with prophylactic mitomycin C treatment than therapeutic mitomycin C treatment. There was, however, an anterior stromal acellular zone (approximately 20% of the total stroma) in eyes treated with mitomycin C, which persisted to the maximum follow-up of 6 months. CONCLUSIONS Mitomycin C treatment induces apoptosis of keratocytes and myofibroblasts, but the predominate effect in inhibiting or treating haze appears to be at the level of blocked replication of keratocytes or other progenitor cells of myofibroblasts. Treatment with 0.002% mitomycin C for 12 seconds to 1 minute appears to be just as effective as higher concentrations for longer duration in the rabbit model. However, a persistent decrease in keratocyte density in the anterior stroma could be a warning sign for future complications and treatment should be reserved for patients with significant risk of developing haze after PRK.
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Affiliation(s)
- Marcelo V Netto
- The Cole Eye Institute, The Cleveland Clinic, Cleveland, Ohio 44195, USA
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19
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Abstract
Several laser and non-laser refractive surgical procedures have been used to modify the shape of the cornea and correct myopia, hyperopia, astigmatism, and presbyopia. Introduction of the excimer laser to reshape the cornea has resulted in remarkable developments in the correction of these refractive errors. Combined with other advanced ophthalmological instruments, laser refractive eye surgery has resulted in a substantial rise in the safety, efficacy, and predictability of surgical outcomes. Despite these advances, certain limitations and complications persist. In this review, we describe the history, preoperative assessment, surgical techniques, outcomes, and complications of laser refractive surgery.
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Affiliation(s)
- Tohru Sakimoto
- Massachusetts Eye and Ear Infirmary, the Schepens Eye Research Institute, Harvard Medical School, Boston, MA 02114, USA
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20
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Netto MV, Mohan RR, Ambrósio R, Hutcheon AEK, Zieske JD, Wilson SE. Wound healing in the cornea: a review of refractive surgery complications and new prospects for therapy. Cornea 2005; 24:509-22. [PMID: 15968154 DOI: 10.1097/01.ico.0000151544.23360.17] [Citation(s) in RCA: 306] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
PURPOSE The corneal wound healing response is of particular relevance for refractive surgical procedures since it is a major determinant of efficacy and safety. The purpose of this review is to provide an overview of the healing response in refractive surgery procedures. METHODS Literature review. RESULTS LASIK and PRK are the most common refractive procedures; however, alternative techniques, including LASEK, PRK with mitomycin C, and Epi-LASIK, have been developed in an attempt to overcome common complications. Clinical outcomes and a number of common complications are directly related to the healing process and the unpredictable nature of the associated corneal cellular response. These complications include overcorrection, undercorrection, regression, corneal stroma opacification, and many other side effects that have their roots in the biologic response to surgery. The corneal epithelium, stroma, nerves, inflammatory cells, and lacrimal glands are the main tissues and organs involved in the wound healing response to corneal surgical procedures. Complex cellular interactions mediated by cytokines and growth factors occur among the cells of the cornea, resulting in a highly variable biologic response. Among the best characterized processes are keratocyte apoptosis, keratocyte necrosis, keratocyte proliferation, migration of inflammatory cells, and myofibroblast generation. These cellular interactions are involved in extracellular matrix reorganization, stromal remodeling, wound contraction, and several other responses to surgical injury. CONCLUSIONS A better understanding of the complete cascade of events involved in the corneal wound healing process and anomalies that lead to complications is critical to improve the efficacy and safety of refractive surgical procedures. Recent advances in understanding the biologic and molecular processes that contribute to the healing response bring hope that safe and effective pharmacologic modulators of the corneal wound healing response may soon be developed.
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Affiliation(s)
- Marcelo V Netto
- The Cole Eye Institute, The Cleveland Clinic Foundation, OH 44195, USA
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Song JS, Jung HR, Kim HM. Effects of topical tranilast on corneal haze after photorefractive keratectomy. J Cataract Refract Surg 2005; 31:1065-73. [PMID: 15975479 DOI: 10.1016/j.jcrs.2004.09.056] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2004] [Indexed: 10/25/2022]
Abstract
PURPOSE To determine whether topical tranilast might reduce corneal haze through suppression of transforming growth factor (TGF)-beta1 synthesis in keratocyte after photorefractive keratectomy. SETTING Department of Ophthalmology, Korea University College of Medicine, Seoul, Republic of Korea. METHODS Photorefractive keratectomy was performed on 48 eyes of 28 white rabbits and 24 eyes in a tranilast group were treated with tranilast solution, and the other 24 eyes in control group were treated with saline after laser ablation. The grades of corneal haze at 1, 2, 4, and 8 weeks after surgery were evaluated in 10 eyes of each group for comparison. Immunohistochemistry was performed on 10 eyes of each group, and Western blot analysis was done on 4 eyes of each group for studying TGF-beta1 expression at postoperative day 7. RESULTS There was no statistically significant difference in corneal haze between 2 groups from week 1 to week 4 after surgery, but a significant difference was found at week 8 after photorefractive keratectomy (P=.02). The mean number of keratocytes that expressed TGF-beta1 in the tranilast group was 58.3 (+/-17.2), which showed significant difference, compared with that of the control group, 104.5 (+/-23.0) (P<.01). Western blot analysis also revealed that the amount of TGF-beta1 in tranilast group was slightly less than the control group. CONCLUSIONS Topical tranilast could reduce corneal haze by suppressing TGF-beta1 expression in keratocytes after photorefractive keratectomy.
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Affiliation(s)
- Jong-Suk Song
- Department of Ophthalmology, Gil Medical Center, Gachon Medical School, Incheon, Republic of Korea
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22
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Hammer T, Giessler S, Duncker GIW, Peschke E. Korneale Wundheilungsreaktionen nach hyperoper PRK und LASIK. Ophthalmologe 2005; 102:39-45. [PMID: 15205908 DOI: 10.1007/s00347-004-1059-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND The purpose of this study was to investigate the influence of different postoperative treatments on the wound healing reaction in the anterior stroma after PRK and in the interface area after LASIK. METHODS Seventy-two corneal buttons of refractively treated rabbit eyes underwent different postoperative eyedrop regimens with antibiotics and/or steroids or additional UV-B irradiation. Morphological and immunohistological investigations were performed 6 months postoperatively by light and transmission electron microscopy. RESULTS PRK eyes showed interdigitations between the epithelia and the anterior stroma. LASIK-treated eyes showed only minor changes between epithelia and stroma in the incisional region. Only a slight increase in deposits of fibrillar extracellular matrix components were detectable in the interface region. CONCLUSIONS The clinically important problem of haze after PRK is caused by the interdigitations between epithelia and anterior stroma. The delicate wound healing reactions in the interface region in LASIK eyes corresponded to the clinically visible minor changes in these corneas.
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Affiliation(s)
- T Hammer
- Augenklinik und Poliklinik, Martin-Luther-Universität, Halle-Wittenberg.
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23
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Ishihara M, Sato M, Sato S, Arai T, Obara M, Kikuchi M. Assessment of expressions of heat shock protein (HSP 72) and apoptosis after ArF excimer laser ablation of the cornea. JOURNAL OF BIOMEDICAL OPTICS 2004; 9:187-192. [PMID: 14715072 DOI: 10.1117/1.1630605] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We immunohistochemically studied expressions of inducible heat shock protein 70 (HSP 72) and apoptosis of corneas ablated with an ArF excimer laser. The temperature of corneal surfaces and laser-induced optical emission spectra were measured in real time as direct physical parameters related to the ablation mechanism. To the best of the authors' knowledge, there have been no experimental studies regarding the influence of physical parameters directly related to the ablation mechanism on corneal reactions at the cell level after laser ablation. The expression of HSP 72 was mainly localized in the regenerative epithelium, which was confirmed to be caused by laser ablation. The HSP 72 positive cell ratios had a correlation with thermal dose, which was derived from the measured time courses of temperature. Expressions of both HSP 72 and apoptosis depended on the thermal dose and elapsed time after ablation. HSP 72 and apoptosis could be seen up to a few hundred micrometers into the stroma, only at a fluence with an optical breakdown emission. This could have been caused by shock waves induced by the optical breakdown.
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Affiliation(s)
- Miya Ishihara
- Department of Medical Engineering, National Defense Medical College, Saitama, Japan.
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24
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Donnenfeld ED, Solomon R, Biser S. Laser in situ keratomileusis after penetrating keratoplasty. Int Ophthalmol Clin 2002; 42:67-87. [PMID: 12409923 DOI: 10.1097/00004397-200210000-00008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Eric D Donnenfeld
- Ophthalmic Consultants of Long Island, Rockville, Centre, NY 11570, USA
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Castro-Muñozledo F, Ozorno-Zarate J, Naranjo-Tackman R, Kuri-Harcuch W. Frozen cultured sheets of epidermal keratinocytes in reepithelialization and repair of the cornea after photorefractive keratectomy. J Cataract Refract Surg 2002; 28:1671-80. [PMID: 12231330 DOI: 10.1016/s0886-3350(01)01349-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To determine whether frozen cultured sheets of human allogeneic epidermal keratinocytes (CEAK) improved wound repair after experimental corneal ablation by photorefractive keratectomy (PRK). SETTING Hospital "Luis Sanchez Bulnes" de la Asociación para Evitar la Ceguera en Mexico, I.A.P, and Department of Cell Biology, CINVESTAV-IPN, Mexico City, Mexico. METHODS Transepithelial PRK was performed in the right eye of male albino rabbits to obtain a 112 microm deep and 6.0 mm diameter ablation zone. In 17 eyes, the ablations were covered with frozen CEAK; in 11 eyes, the ablations were covered with a disposable contact lens without the cultured sheets; and in the control group (13 eyes), the ablations were not covered. Subepithelial fibrosis and reepithelialization of the ablated zone were evaluated in serial paraffin-embedded tissue sections from all wounds. RESULTS Treatment with CEAK reduced fibroblast proliferation and the inflammatory response beneath the ablated zone and produced better organization of the newly formed epithelium by eliminating significant hyperplasia or discontinuities in the periodic acid Shiff-stained basement membrane. It also led to accelerated reepithelialization. CONCLUSIONS The use of frozen CEAK as a biologically active wound dressing improved tissue repair at 1 month in corneas ablated by transepithelial PRK in the male albino rabbit model. Treatment with CEAK could improve the outcome of PRK in humans.
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Affiliation(s)
- Federico Castro-Muñozledo
- Department of Cell Biology, Centro de Investigación y Estudios Avanzados del IPN, Mexico City, Mexico.
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Abstract
Laser subepithelial keratomileusis (LASEK) is a relatively new refractive surgical technique that purportedly combines the advantages of laser in-situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). Like LASIK, on the one hand, it employs a "flap" and consequently has the advantages of faster visual recovery, less postoperative pain, reduced stromal haze, and faster epithelial healing than PRK. Like PRK, on the other hand, because the procedure is performed on the anterior cornea, there are virtually no flap- or interface-related complications per se. It may thus be safer for patients who are at an inherently higher risk of developing flap complications, such as those with small palpebral fissures, deep-set eyes, corneal basement membrane dystrophy, and extremely steep or flat corneas. Furthermore, it conserves precious stroma in eyes with thin corneas or high myopia, which otherwise may not qualify for LASIK. It may also be more apropos for patients whose jobs or recreational activities put them at a higher risk of corneal trauma. In a very timely fashion, for reasons discussed below, LASEK may also prove to be superior to LASIK in customized ablations.
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Affiliation(s)
- Mohammad H Dastjerdi
- University of Michigan, W.K. Kellogg Eye Center, Ann Arbor, Michigan 48105, USA.
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27
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Baldwin HC, Marshall J. Growth factors in corneal wound healing following refractive surgery: A review. ACTA OPHTHALMOLOGICA SCANDINAVICA 2002; 80:238-47. [PMID: 12059860 DOI: 10.1034/j.1600-0420.2002.800303.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The first part of this review article aims to provide important basic definitions of growth factor terminology, and to put forward a model for understanding the role of growth factors in a wound healing context. In the second part of the paper, we review the literature on growth factors in the cornea, including that on changes associated with wound healing following refractive surgery in the epithelial, stromal, and endothelial layers. The role of growth factors in stromal removal, corneal neovascularization, corneal innervation and wound healing is considered. The importance of the epithelial-stromal interaction is discussed, including the role of growth factors in keratocyte apoptosis. In the final section, we review the current literature on endogenous and exogenous modulation of growth factors in corneal wound healing. This includes important in vitro work but aims to emphasize clinically relevant results. Photorefractive keratectomy (PRK) may have short-term complications such as pain and haze, whereas laser in situ keratomilieusis (LASIK) may have longer-term adverse effects on corneal biomechanics. The emerging technique of laser epithelial keratomilieusis (LASEK) provides an interesting alternative wound which may be less susceptible to the inherent complications of PRK and LASIK. At present, the phenomenon of iatrogenic keratectasia following LASIK is not fully understood, but these features of wound healing following PRK may be amenable to growth factor modulation.
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Chamberlain J. Transforming growth factor-beta: a promising target for anti-stenosis therapy. CARDIOVASCULAR DRUG REVIEWS 2002; 19:329-44. [PMID: 11830751 DOI: 10.1111/j.1527-3466.2001.tb00074.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Transforming growth factor-beta (TGF-beta) is the general name for a family of cytokines which have widespread effects on many aspects of growth and development. The TGF-beta isoforms are produced by most cell types and exert a wide range of effects in a context-dependent autocrine, paracrine or endocrine fashion via interactions with distinct receptors on the cell surface. TGF-beta is involved in the wound healing process and, thus plays a significant role in the formation of a restenotic lesion after percutaneous transluminal coronary angioplasty (PTCA) or stenting. Perhaps because of its wide-ranging effects, TGF-beta is usually released from cells in a latent form, and its activation and signaling are complex. Manipulation of the TGF-beta1, TGF-beta2, and TGF-beta3 isoforms by inhibiting their expression, activation, or signaling reduces scarring and fibrosis in animal models. However, to date, few have reached clinical trial. This review summarizes current knowledge on the activation and signaling of TGF-beta, and focuses on the anti-TGF-beta strategies which may lead to clinical applications in the prevention of restenosis following PTCA or stenting.
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Affiliation(s)
- J Chamberlain
- Cardiovascular Research Group, Section of Medicine, University of Sheffield, Clinical Sciences Centre, Northern General Hospital, Herries Road, Sheffield, S5 7AU, UK.
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Lee JB, Choe CM, Kim HS, Seo KY, Seong GJ, Kim EK. Comparison of TGF-β1 in Tears Following Laser Subepithelial Keratomileusis and Photorefractive Keratectomy. J Refract Surg 2002; 18:130-4. [PMID: 11934200 DOI: 10.3928/1081-597x-20020301-05] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare the release of tear fluid transforming growth factor-beta1 (TGF-beta1) of 15 patients who underwent photorefractive keratectomy (PRK) in one eye and laser subepithelial keratomileusis (LASEK) in the other eye. METHODS Tear fluid samples were collected with scaled microcapillary tubes preoperatively (day 0) and on the first, second, and seventh postoperative days. We calculated the release of TGF-beta1 (tear fluid flow-corrected concentrations of TGF-beta1) by multiplying the concentration by capillary tear fluid flow and also evaluated corneal haze at 1, 3, and 6 months after PRK or LASEK. RESULTS The median TGF-beta1 release values were: Day 0: 50.6 pg/min (range 0 to 101.6 pg/min) for PRK and 56.7 pg/min (range 0 to 121.8 pg/min) for LASEK (P=.496); Day 1: 240.6 pg/min (range 56.6 to 1120.2 pg/min) for PRK and 155.2 pg/min (range 45.1 to 480.4 pg/min) for LASEK, which showed a significant difference between the two procedures (P=.041); Day 2: 395.7 pg/min (range 92.3 to 1150.7 pg/min) for PRK and 185.2 pg/min (range 41.4 to 872.5 pg/min) for LASEK (P=.004); and Day 7: 91.3 pg/min (range 0 to 225.4 pg/min) for PRK and 74.3 pg/min (range 0 to 187.1 pg/min) for LASEK, (P=.244). The mean corneal haze score at 1 month after PRK was 0.88 +/- 0.50 and 0.53 +/- 0.29 after LASEK, and a statistically significant difference was noted between the two groups (P=.005). At 3 months (P=.083) and 6 months (P=.157) after the procedures, there were no statistically significant differences. CONCLUSIONS A lower amount of tear fluid transforming growth factor-beta1 was released in the early postoperative days following LASEK than in PRK. The lower grade of corneal haze seen in LASEK than PRK in the early postoperative period may come from a decreased release of TGF-beta1, which may have a role in wound healing.
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Affiliation(s)
- Jae Bum Lee
- Department of Ophthalmology, Yonsei University College of Medicine, Yongdong Severance Hospital, Seoul, Korea
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30
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Abstract
The introduction of the anti-cancer drugs Mitomycin and 5-fluorouracil as anti-scarring agents within the last decade, has greatly improved surgical results of glaucoma filtration surgery. However, a number of problems associated with their use have emerged. At the same time, the transforming growth factor-beta (TGF-beta) has been identified as an important component of wound healing, particularly in the conjunctival scarring response. Recent developments in molecular therapy offer exciting prospects for the modulation of wound healing, specifically those targeting TGF-beta. As TGF-beta is such a potent stimulant of scarring, this review examines its biology and role in ocular wound healing and repair, and discusses promising new approaches to modifying its activity.
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Affiliation(s)
- M Francesca Cordeiro
- Department of Pathology, Institute of Ophthalmology and Moorfields Eye Hospital, Bath Street, London EC1V 9EL, UK.
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Kaji Y, Amano S, Oshika T, Obata H, Ohashi T, Sakai H, Shirasawa E, Tsuru T, Yamashita H. Effect of anti-inflammatory agents on corneal wound-healing process after surface excimer laser keratectomy. J Cataract Refract Surg 2000; 26:426-31. [PMID: 10713241 DOI: 10.1016/s0886-3350(99)00358-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To investigate the effect of anti-inflammatory agents on conjunctival inflammation and corneal haze formation after excimer laser keratectomy. SETTING Department of Ophthalmology, University of Tokyo Faculty of Medicine, Tokyo, Japan. METHODS After excimer laser keratectomy was performed in 21 rabbits (42 eyes), saline, betamethasone 0.1%, or diclofenac 0.1% was topically applied 6 times a day for 4 weeks and then 3 times a day for 8 weeks. The degree of conjunctival inflammation was determined 1, 2, 3, and 7 days after the keratectomy. The degree of corneal haze was quantitatively measured using a digital analyzer before and once a week after the keratectomy. The expression of type IV collagen in the corneas at baseline and 4 and 12 weeks after the keratectomy was examined immunohistochemically. RESULTS Compared with saline, betamethasone and diclofenac significantly decreased early-phase conjunctival inflammation. Betamethasone significantly inhibited corneal haze formation compared with saline at 3 to 5 and 8 to 12 weeks. Diclofenac did not inhibit corneal haze formation significantly. Although betamethasone tended to be more effective in inhibiting corneal haze formation and deposition of type IV collagen than diclofenac, there was no statistical difference between the 2 anti-inflammatory agents. CONCLUSION Topically applied betamethasone effectively suppressed corneal haze formation after excimer laser keratectomy. Diclofenac was not statistically effective in inhibiting corneal haze formation.
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Affiliation(s)
- Y Kaji
- Department of Ophthalmology, University of Tokyo Faculty of Medicine, Tokyo, Japan
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Tabbara KF, El-Sheikh HF, Sharara NA, Aabed B. Corneal haze among blue eyes and brown eyes after photorefractive keratectomy. Ophthalmology 1999; 106:2210-5. [PMID: 10571361 DOI: 10.1016/s0161-6420(99)90507-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND To compare the incidence and severity of corneal haze after photorefractive keratectomy (PRK) among white patients with blue eyes and Saudi patients with brown eyes. DESIGN Retrospective, nonrandomized, comparative trial. PARTICIPANTS A total of 150 patients (71 females and 79 males) were included in this study. Two hundred sixty-six eyes of 150 patients were subjected to PRK. One hundred blue eyes of 50 white patients and 166 brown eyes of 100 Saudi patients were included in this study. METHODS Two hundred sixty-six eyes of 150 patients were subjected to PRK with the Chiron Technolas Keracor 117C for the correction of myopia and astigmatism. MAIN OUTCOME MEASURES All patients had complete ophthalmologic examinations, visual acuity testing, intraocular pressure, pachymetry, corneal haze assessment (0-4+), and computerized corneal topography. RESULTS There were 266 eyes of 150 patients with 100 blue irides and 166 brown irides. The spherical equivalent was -0.50 diopter (D) to -8.75 D. The mean postoperative spherical equivalent at 6 months was -0.063 D (standard deviation [SD], +/-0.595) in blue eyes compared to -0.28 D (SD, +/-0.683) in brown eyes (P = 0.006). Ninety-five (95%) of 100 of the blue eyes achieved +/- 1 D of attempted correction compared to 148 (89.2%) of the 166 brown eyes. All patients with blue eyes had a visual acuity of 20/30 or better compared to 153 (92.2%) of the 166 brown eyes (P = 0.009). Forty-eight (18.04%) eyes had minimal to mild haze, 3 (1.12%) eyes had moderate haze, and 2 (0.75%) eyes had severe haze. The incidence of corneal haze among brown eyes was 48 (28.9%) of 166 eyes compared to 5 (5%) of 100 in blue eyes (P < 0.001). The difference remained significant after adjustment for age and gender with a P value of 0.0283. The relative risk for developing haze in brown eyes was found to be 7.72. CONCLUSION The incidence of corneal haze after PRK was significantly higher among Saudi patients with brown irides than among white patients with blue irides. This suggests that racial factors may play a role in the development of corneal haze.
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Affiliation(s)
- K F Tabbara
- The Eye Center and The Eye Foundation for Research in Ophthalmology, Riyadh, Saudi Arabia
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Excimer laser photorefractive keratectomy (PRK) for myopia and astigmatism11Prepared by the Committee on Ophthalmic Procedures Assessment Refractive Surgery Panel, Christopher J. Rapuano, MD, Chair, and approved by the American Academy of Ophthalmology’s Board of Trustees December 14, 1998. Ophthalmology 1999. [DOI: 10.1016/s0161-6420(99)90085-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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