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Guclu H, Sattarpanah S, Gurlu V. Association of Changes in Thickness of Limbal Epithelial and Stroma with Corneal Scars Detected by High-Resolution Anterior Segment Optic Coherence Tomography. Klin Monbl Augenheilkd 2024; 241:744-750. [PMID: 35504299 DOI: 10.1055/a-1842-2683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
AIM To investigate the corneal central and limbal thickness in cornea scar patients using high-resolution anterior segment optical coherence tomography (AS-OCT) and to determine the changes in the limbal region due to the corneal scar. Also, to evaluate tear film parameters in scar patients. METHODS Thirty patients with central corneal scar and 30 control subjects. The control subjects were healthy individuals who came to our clinic for routine ophthalmological examination. They were enrolled in this matched case-control study. Central epithelial thickness (ET), stromal thickness (ST), limbal epithelial thickness (LET), and limbal stromal thickness (LST) were analyzed using high-resolution AS-OCT. For evaluation of the ocular surface, the following techniques were used: tear break-up time (BUT) employing standard sterile strips of fluorescein sodium, Schirmer test-I (SCH), and the Ocular Surface Disease Index (OSDI) Questionnaire. RESULTS The mean central ET of the patient group was 51.5 ± 12.4 µm, while the mean central ET of the control group was 59.2 ± 9.0 µm. There was a statistically significant difference between patients and controls (p = 0.008). The mean LST of the patients was 747.9 ± 115.7 µm, and the mean LST of the controls was 726.3 ± 79.7 µm. There was a statistically significant difference between patients and controls according to BUT (p = 0.009) and SCH (p = 0.04). However, there was no significant difference between OSDI results of patients and controls (p = 0.08). CONCLUSION Corneal monitoring with high-resolution AS-OCT is a simple, noninvasive, useful technique for corneal scar patients. Cornea scars cause decreased ET. This result could be associated with lower tear film parameters in scar patients. The scar length is associated with higher intraocular pressure (IOP) values. Decreased LET and increased LST were detected in scar patients.
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Affiliation(s)
- Hande Guclu
- Ophthalmology, Trakya University, Faculty of Medicine, Edirne, Turkey
| | | | - Vuslat Gurlu
- Ophthalmology, Trakya University, Faculty of Medicine, Edirne, Turkey
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Miralles E, Kamma-Lorger CS, Domènech Ò, Sosa L, Casals I, Calpena AC, Silva-Abreu M. Assessment of Efficacy and Safety Using PPAR-γ Agonist-Loaded Nanocarriers for Inflammatory Eye Diseases. Int J Mol Sci 2022; 23:ijms231911184. [PMID: 36232486 PMCID: PMC9570464 DOI: 10.3390/ijms231911184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/18/2022] [Accepted: 09/19/2022] [Indexed: 11/16/2022] Open
Abstract
Drug-loaded nanocarriers (NCs) are new systems that can greatly improve the delivery and targeting of drugs to specific tissues and organs. In our work, a PPAR-γ agonist loaded into polymeric NCs was prepared, stabilized by spray-drying, and tested in vitro, ex vivo, and in vivo (animal models) to provide a safe formulation for optical anti-inflammatory treatments. The NCs were shown to be well tolerated, and no signs of irritancy or alterations of the eye properties were detected by the in vitro HET-CAM test and in vivo Draize test. Furthermore, no signs of cytotoxicity were found in the NC formulations on retinoblastoma cells (Y-79) analyzed using the alamarBlue assay, and the transmittance experiments evidenced good corneal transparency with the formulations tested. The ocular anti-inflammatory study confirmed the significant prevention efficacy using the NCs, and these systems did not affect the corneal tissue structure. Moreover, the animal corneal structure treated with the NCs was analyzed using X-ray diffraction using synchrotron light. Small-angle X-ray scattering (SAXS) analysis did not show a significant difference in corneal collagen interfibrillar spacing after the treatment with freshly prepared NCs or NCs after the drying process compared to the corresponding negative control when inflammation was induced. Considering these results, the PPAR-γ agonist NCs could be a safe and effective alternative for the treatment of inflammatory ocular processes.
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Affiliation(s)
- Esther Miralles
- CCiTUB (Scientific and Technological Centers), University of Barcelona, 08028 Barcelona, Spain
| | | | - Òscar Domènech
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), University of Barcelona, 08028 Barcelona, Spain
| | - Lilian Sosa
- Pharmaceutical Technology Research Group, Faculty of Chemical Sciences and Pharmacy, National Autonomous University of Honduras (UNAH), Tegucigalpa 11101, Honduras
| | - Isidre Casals
- CCiTUB (Scientific and Technological Centers), University of Barcelona, 08028 Barcelona, Spain
| | - Ana Cristina Calpena
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), University of Barcelona, 08028 Barcelona, Spain
| | - Marcelle Silva-Abreu
- Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain
- Institute of Nanoscience and Nanotechnology (IN2UB), University of Barcelona, 08028 Barcelona, Spain
- Correspondence: ; Tel.: +34-93-402-4578
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Bonzano C, Olivari S, Cutolo CA, Macrì A, Sindaco D, Borroni D, Bonzano E, Traverso CE. Recombinant Human Nerve Growth Factor (Cenegermin)–Driven Corneal Wound Healing Process: An Evidence-Based Analysis. Front Pharmacol 2022; 12:760507. [PMID: 35153738 PMCID: PMC8832138 DOI: 10.3389/fphar.2021.760507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 12/13/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: To evaluate anterior segment optical coherence tomography (AS-OCT) to detect the wound healing process as per monitoring the effectiveness of cenegermin to treat moderate to severe neurotrophic keratoplasty. Methods: A retrospective chart review was realized to identify patients treated with cenegermin at the Clinica Oculistica, University of Genoa, Italy. All patients underwent careful examinations at baseline and follow-up visits. AS-OCT scans centered on the minimum corneal thickness (CT) area were always performed. We compared findings of AS-OCT with the findings from the slit-lamp examination. A linear regression analysis was used to evaluate factors associated with corneal healing. A further analysis, including a control group treated with 50% autologous serum (AS), was done to investigate and compare the efficacy of cenegermin. Results: Data from 16 eyes were studied. The average patients' age was 60.9 ± 21.1 years; five (31.2%) eyes experienced persistent epithelial defect and 11 (68.8%) eyes had neurotrophic corneal ulcer. The average reepithelialization time was 3.9 ± 0.5 weeks in the cenegermin group versus 5.9 ± 1.9 weeks in the AS group (p < 0.01). The AS‐OCT scans revealed an average CT at the thinnest point of 276.3 ± 74.1 μm before treatment with an average increase of 176.5 ± 60.3 μm at the end of the cenegermin treatment (B = −0.15; p = 0.035). The AS-OCT percentage increase in corneal thickness between the two groups was statistically significant (p < 0.02). Conclusion: Understanding the cascade of events involved in the nerve growth factor–driven corneal wound healing process is clinically meaningful for the clinician. AS-OCT is an effective tool for systematic anterior segment imaging, allowing the detailed detection of the front-to-back layered corneal structure for quantitative analysis and monitoring of the healing process.
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Affiliation(s)
- Chiara Bonzano
- Eye Clinic, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
- IRCCS San Martino Polyclinic Hospital, Genoa, Italy
- *Correspondence: Chiara Bonzano,
| | - Sara Olivari
- Eye Clinic, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
- IRCCS San Martino Polyclinic Hospital, Genoa, Italy
| | - Carlo Alberto Cutolo
- Eye Clinic, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
- IRCCS San Martino Polyclinic Hospital, Genoa, Italy
| | - Angelo Macrì
- IRCCS San Martino Polyclinic Hospital, Genoa, Italy
| | - Daniele Sindaco
- Eye Clinic, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
- IRCCS San Martino Polyclinic Hospital, Genoa, Italy
| | - Davide Borroni
- Cornea Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom
| | - Elisabetta Bonzano
- Department of Radiation Oncology, IRCCS San Matteo Polyclinic Foundation, Pavia, Italy
- PhD School in Experimental Medicine, University of Pavia, Pavia, Italy
| | - Carlo Enrico Traverso
- Eye Clinic, Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
- IRCCS San Martino Polyclinic Hospital, Genoa, Italy
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Animal model with structural similarity to human corneal collagen fibrillar arrangement. Anat Sci Int 2021; 96:286-293. [PMID: 33392925 DOI: 10.1007/s12565-020-00590-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 11/24/2020] [Indexed: 12/15/2022]
Abstract
Rabbit and porcine corneas have been used in scientific research due to their structural similarity to the human cornea. Currently, there are no studies that have compared corneal collagen fibrillar diameter, interfibrillar distance and interlamellar distance between human and animal models. Ten pairs of porcine, rabbit, and human corneas were used. These were analysed using light and Transmission Electron microscopy. The collagen fibrillar diameter, interfibrillar distance and interlamellar distance were statistically compared between porcine, rabbit and human corneas. The human, porcine and rabbit; mean collagen fibrillar diameters were: 24.52 ± 2.09 nm; 32.87 ± 0.87 nm; and 33.67 ± 1.97 nm. The mean interfibrillar distances were: 46.10 ± 2.44 nm; 53.33 ± 2.24 nm; and 52.87 ± 2.73 nm, respectively. The collagen fibrillar diameter and interfibrillar distance of porcine and rabbit corneas were significantly different (p < 0.001) to the human corneal values but not form each other. The interlamellar distance of human, porcine and rabbit corneas was: 2190 ± 820 nm; 6460 ± 1180 nm; and 4410 ± 1330 nm, respectively. All the comparisons were statistically different, in porcine versus rabbit at the p < 0.01 level and both porcine and rabbit versus human at the p < 0.001 level. Histologically, all five layers (epithelium, Bowman's layer, stroma, Descemet membrane and endothelium) of the cornea were visible in all the three species. While neither animal model was structurally identical to the human cornea, they are both relatively close to being used as models to study the biomechanical effects of external insults/treatments to be extrapolated to the human cornea.
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Koudouna E, Spurlin J, Babushkina A, Quantock AJ, Jester JV, Lwigale P. Recapitulation of normal collagen architecture in embryonic wounded corneas. Sci Rep 2020; 10:13815. [PMID: 32796881 PMCID: PMC7427794 DOI: 10.1038/s41598-020-70658-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 07/31/2020] [Indexed: 02/06/2023] Open
Abstract
Wound healing is characterized by cell and extracellular matrix changes mediating cell migration, fibrosis, remodeling and regeneration. We previously demonstrated that chick fetal wound healing shows a regenerative phenotype regarding the cellular and molecular organization of the cornea. However, the chick corneal stromal structure is remarkably complex in the collagen fiber/lamellar organization, involving branching and anastomosing of collagen bundles. It is unknown whether the chick fetal wound healing is capable of recapitulating this developmentally regulated organization pattern. The purpose of this study was to examine the three-dimensional collagen architecture of wounded embryonic corneas, whilst identifying temporal and spatial changes in collagen organization during wound healing. Linear corneal wounds that traversed the epithelial layer, Bowman´s layer, and anterior stroma were generated in chick corneas on embryonic day 7. Irregular thin collagen fibers are present in the wounded cornea during the early phases of wound healing. As wound healing progresses, the collagen organization dramatically changes, acquiring an orthogonal arrangement. Fourier transform analysis affirmed this observation and revealed that adjacent collagen lamellae display an angular displacement progressing from the epithelium layer towards the endothelium. These data indicate that the collagen organization of the wounded embryonic cornea recapitulate the native macrostructure.
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Affiliation(s)
- Elena Koudouna
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA.,Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, UK
| | - James Spurlin
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Anna Babushkina
- Department of Biosciences, Rice University, Houston, TX, USA
| | - Andrew J Quantock
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, UK
| | - James V Jester
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA
| | - Peter Lwigale
- Department of Biosciences, Rice University, Houston, TX, USA.
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Patel M, Nakaji‐Hirabayashi T, Matsumura K. Effect of dual‐drug‐releasing micelle–hydrogel composite on wound healingin vivoin full‐thickness excision wound rat model. J Biomed Mater Res A 2019; 107:1094-1106. [DOI: 10.1002/jbm.a.36639] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 01/24/2019] [Indexed: 01/01/2023]
Affiliation(s)
- Monika Patel
- School of Materials ScienceJapan Advanced Institute of Science and Technology Nomi, Ishikawa, 923‐1292 Japan
| | - Tadashi Nakaji‐Hirabayashi
- Graduate School of Science and EngineeringUniversity of Toyama Toyama, 930‐8555 Japan
- Graduate School of Innovative Life ScienceUniversity of Toyama Toyama, 930‐8555 Japan
| | - Kazuaki Matsumura
- School of Materials ScienceJapan Advanced Institute of Science and Technology Nomi, Ishikawa, 923‐1292 Japan
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Liu Y, Liu X, Wu M, Ji P, Lv H, Deng L. A collagen film with micro-rough surface can promote the corneal epithelization process for corneal repair. Int J Biol Macromol 2019; 121:233-238. [DOI: 10.1016/j.ijbiomac.2018.10.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 08/27/2018] [Accepted: 10/07/2018] [Indexed: 11/28/2022]
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Sorkio A, Koch L, Koivusalo L, Deiwick A, Miettinen S, Chichkov B, Skottman H. Human stem cell based corneal tissue mimicking structures using laser-assisted 3D bioprinting and functional bioinks. Biomaterials 2018; 171:57-71. [PMID: 29684677 DOI: 10.1016/j.biomaterials.2018.04.034] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 04/11/2018] [Accepted: 04/14/2018] [Indexed: 12/11/2022]
Abstract
There is a high demand for developing methods to produce more native-like 3D corneal structures. In the present study, we produced 3D cornea-mimicking tissues using human stem cells and laser-assisted bioprinting (LaBP). Human embryonic stem cell derived limbal epithelial stem cells (hESC-LESC) were used as a cell source for printing epithelium-mimicking structures, whereas human adipose tissue derived stem cells (hASCs) were used for constructing layered stroma-mimicking structures. The development and optimization of functional bioinks was a crucial step towards successful bioprinting of 3D corneal structures. Recombinant human laminin and human sourced collagen I served as the bases for the functional bioinks. We used two previously established LaBP setups based on laser induced forward transfer, with different laser wavelengths and appropriate absorption layers. We bioprinted three types of corneal structures: stratified corneal epithelium using hESC-LESCs, lamellar corneal stroma using alternating acellular layers of bioink and layers with hASCs, and finally structures with both a stromal and epithelial part. The printed constructs were evaluated for their microstructure, cell viability and proliferation, and key protein expression (Ki67, p63α, p40, CK3, CK15, collagen type I, VWF). The 3D printed stromal constructs were also implanted into porcine corneal organ cultures. Both cell types maintained good viability after printing. Laser-printed hESC-LESCs showed epithelial cell morphology, expression of Ki67 proliferation marker and co-expression of corneal progenitor markers p63α and p40. Importantly, the printed hESC-LESCs formed a stratified epithelium with apical expression of CK3 and basal expression of the progenitor markers. The structure of the 3D bioprinted stroma demonstrated that the hASCs had organized horizontally as in the native corneal stroma and showed positive labeling for collagen I. After 7 days in porcine organ cultures, the 3D bioprinted stromal structures attached to the host tissue with signs of hASCs migration from the printed structure. This is the first study to demonstrate the feasibility of 3D LaBP for corneal applications using human stem cells and successful fabrication of layered 3D bioprinted tissues mimicking the structure of the native corneal tissue.
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Affiliation(s)
- Anni Sorkio
- BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Arvo Ylpön katu 34, FI-33520 Tampere, Finland; Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany
| | - Lothar Koch
- Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany
| | - Laura Koivusalo
- BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Arvo Ylpön katu 34, FI-33520 Tampere, Finland
| | - Andrea Deiwick
- Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany
| | - Susanna Miettinen
- BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Arvo Ylpön katu 34, FI-33520 Tampere, Finland; Science Center, Tampere University Hospital, P.O. BOX 2000, FI-33521 Tampere, Finland
| | - Boris Chichkov
- Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany; Institute for Quantum Optics, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany
| | - Heli Skottman
- BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Arvo Ylpön katu 34, FI-33520 Tampere, Finland.
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Early wound healing of laser in situ keratomileusis-like flaps after treatment with human corneal stromal stem cells. J Cataract Refract Surg 2016; 42:302-9. [PMID: 27026456 PMCID: PMC4819535 DOI: 10.1016/j.jcrs.2015.09.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 08/29/2015] [Accepted: 09/01/2015] [Indexed: 02/06/2023]
Abstract
PURPOSE To use a well-established organ culture model to investigate the effects of corneal stromal stem cells on the optical and biomechanical properties of corneal wounds after laser in situ keratomileusis (LASIK)-like flap creation. SETTING School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom. DESIGN Experimental study. METHODS The LASIK-like flaps were produced in sheep corneas. The flap beds were treated with corneal stromal stem cells and were then replaced and allowed to heal for different periods of up to 3 weeks in organ culture. The optical transmission of the cornea, the force required to detach the flap, and the presence of myofibroblasts near the flap bed were measured. RESULTS Corneal stromal stem cell-treated flap beds were statistically significantly more transparent after 3 weeks in culture than the untreated controls. At 3 weeks, the mean force necessary to detach the flap was more than twice the force required for the respective control samples. Concurrently, there were 44% activated cells immediately below the flap margin of the controls compared with 29% in the same region of the corneal stromal stem cell-treated flaps. CONCLUSIONS In this system, the presence of corneal stromal stem cells at the wound margin significantly increased the adherence of LASIK-like flaps while maintaining corneal transparency. It is postulated that this is achieved by the deposition of extracellular connective tissue similar to that found in the normal cornea and by the paucity of activated keratocytes (myofibroblasts), which are known to scatter a significant amount of the incident light. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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10
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Dextran Preserves Native Corneal Structure During Decellularization. Tissue Eng Part C Methods 2016; 22:561-72. [DOI: 10.1089/ten.tec.2016.0017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Kamma-Lorger CS, Pinali C, Martínez JC, Harris J, Young RD, Bredrup C, Crosas E, Malfois M, Rødahl E, Meek KM, Knupp C. Role of Decorin Core Protein in Collagen Organisation in Congenital Stromal Corneal Dystrophy (CSCD). PLoS One 2016; 11:e0147948. [PMID: 26828927 PMCID: PMC4734740 DOI: 10.1371/journal.pone.0147948] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 01/11/2016] [Indexed: 11/18/2022] Open
Abstract
The role of Decorin in organising the extracellular matrix was examined in normal human corneas and in corneas from patients with Congenital Stromal Corneal Dystrophy (CSCD). In CSCD, corneal clouding occurs due to a truncating mutation (c.967delT) in the decorin (DCN) gene. Normal human Decorin protein and the truncated one were reconstructed in silico using homology modelling techniques to explore structural changes in the diseased protein. Corneal CSCD specimens were also examined using 3-D electron tomography and Small Angle X-ray diffraction (SAXS), to image the collagen-proteoglycan arrangement and to quantify fibrillar diameters, respectively. Homology modelling showed that truncated Decorin had a different spatial geometry to the normal one, with the truncation removing a major part of the site that interacts with collagen, compromising its ability to bind effectively. Electron tomography showed regions of abnormal stroma, where collagen fibrils came together to form thicker fibrillar structures, showing that Decorin plays a key role in the maintenance of the order in the normal corneal extracellular matrix. Average diameter of individual fibrils throughout the thickness of the cornea however remained normal.
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Affiliation(s)
- Christina S. Kamma-Lorger
- NCD-BL11, ALBA Synchrotron Light Source, Cerdanyola del Vallés, 08290, Barcelona, Spain
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
| | - Christian Pinali
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
| | - Juan Carlos Martínez
- NCD-BL11, ALBA Synchrotron Light Source, Cerdanyola del Vallés, 08290, Barcelona, Spain
| | - Jon Harris
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
| | - Robert D. Young
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
| | - Cecilie Bredrup
- Department of Ophthalmology, Haukeland University Hospital, 5021 Bergen, Norway
| | - Eva Crosas
- NCD-BL11, ALBA Synchrotron Light Source, Cerdanyola del Vallés, 08290, Barcelona, Spain
| | - Marc Malfois
- NCD-BL11, ALBA Synchrotron Light Source, Cerdanyola del Vallés, 08290, Barcelona, Spain
| | - Eyvind Rødahl
- Department of Ophthalmology, Haukeland University Hospital, 5021 Bergen, Norway
- Department of Clinical Medicine, University of Bergen, 5020 Bergen, Norway
| | - Keith M. Meek
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
| | - Carlo Knupp
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ, United Kingdom
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12
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Abstract
Corneal wound healing is a complex process involving cell death, migration, proliferation, differentiation, and extracellular matrix remodeling. Many similarities are observed in the healing processes of corneal epithelial, stromal and endothelial cells, as well as cell-specific differences. Corneal epithelial healing largely depends on limbal stem cells and remodeling of the basement membrane. During stromal healing, keratocytes get transformed to motile and contractile myofibroblasts largely due to activation of transforming growth factor-β (TGF-β) system. Endothelial cells heal mostly by migration and spreading, with cell proliferation playing a secondary role. In the last decade, many aspects of wound healing process in different parts of the cornea have been elucidated, and some new therapeutic approaches have emerged. The concept of limbal stem cells received rigorous experimental corroboration, with new markers uncovered and new treatment options including gene and microRNA therapy tested in experimental systems. Transplantation of limbal stem cell-enriched cultures for efficient re-epithelialization in stem cell deficiency and corneal injuries has become reality in clinical setting. Mediators and course of events during stromal healing have been detailed, and new treatment regimens including gene (decorin) and stem cell therapy for excessive healing have been designed. This is a very important advance given the popularity of various refractive surgeries entailing stromal wound healing. Successful surgical ways of replacing the diseased endothelium have been clinically tested, and new approaches to accelerate endothelial healing and suppress endothelial-mesenchymal transformation have been proposed including Rho kinase (ROCK) inhibitor eye drops and gene therapy to activate TGF-β inhibitor SMAD7. Promising new technologies with potential for corneal wound healing manipulation including microRNA, induced pluripotent stem cells to generate corneal epithelium, and nanocarriers for corneal drug delivery are discussed. Attention is also paid to problems in wound healing understanding and treatment, such as lack of specific epithelial stem cell markers, reliable identification of stem cells, efficient prevention of haze and stromal scar formation, lack of data on wound regulating microRNAs in keratocytes and endothelial cells, as well as virtual lack of targeted systems for drug and gene delivery to select corneal cells.
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Affiliation(s)
- Alexander V Ljubimov
- Eye Program, Board of Governors Regenerative Medicine Institute, Departments of Biomedical Sciences and Neurosurgery, Cedars-Sinai Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
| | - Mehrnoosh Saghizadeh
- Eye Program, Board of Governors Regenerative Medicine Institute, Departments of Biomedical Sciences and Neurosurgery, Cedars-Sinai Medical Center, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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13
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Quantock AJ, Winkler M, Parfitt GJ, Young RD, Brown DJ, Boote C, Jester JV. From nano to macro: studying the hierarchical structure of the corneal extracellular matrix. Exp Eye Res 2015; 133:81-99. [PMID: 25819457 PMCID: PMC4379421 DOI: 10.1016/j.exer.2014.07.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 07/17/2014] [Accepted: 07/21/2014] [Indexed: 01/22/2023]
Abstract
In this review, we discuss current methods for studying ocular extracellular matrix (ECM) assembly from the 'nano' to the 'macro' levels of hierarchical organization. Since collagen is the major structural protein in the eye, providing mechanical strength and controlling ocular shape, the methods presented focus on understanding the molecular assembly of collagen at the nanometre level using X-ray scattering through to the millimetre to centimetre level using non-linear optical (NLO) imaging of second harmonic generated (SHG) signals. Three-dimensional analysis of ECM structure is also discussed, including electron tomography, serial block face scanning electron microscopy (SBF-SEM) and digital image reconstruction. Techniques to detect non-collagenous structural components of the ECM are also presented, and these include immunoelectron microscopy and staining with cationic dyes. Together, these various approaches are providing new insights into the structural blueprint of the ocular ECM, and in particular that of the cornea, which impacts upon our current understanding of the control of corneal shape, pathogenic mechanisms underlying ectatic disorders of the cornea and the potential for corneal tissue engineering.
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Affiliation(s)
- Andrew J Quantock
- Structural Biophysics Group, Cardiff Centre for Vision Science, School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, UK
| | - Moritz Winkler
- Department of Ophthalmology and Biomedical Engineering, University of California, Irvine, Irvine, CA, USA
| | - Geraint J Parfitt
- Department of Ophthalmology and Biomedical Engineering, University of California, Irvine, Irvine, CA, USA
| | - Robert D Young
- Structural Biophysics Group, Cardiff Centre for Vision Science, School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, UK
| | - Donald J Brown
- Department of Ophthalmology and Biomedical Engineering, University of California, Irvine, Irvine, CA, USA
| | - Craig Boote
- Structural Biophysics Group, Cardiff Centre for Vision Science, School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, UK
| | - James V Jester
- Department of Ophthalmology and Biomedical Engineering, University of California, Irvine, Irvine, CA, USA.
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14
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Wound healing process after corneal stromal thinning observed with anterior segment optical coherence tomography. Cornea 2015; 33:1056-60. [PMID: 25119958 DOI: 10.1097/ico.0000000000000223] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The aim of this study was to observe the wound healing process after corneal stromal thinning by using anterior segment optical coherence tomography (AS-OCT) and a slit lamp. METHODS Four patients with corneal stromal thinning (2 patients: corneal iron foreign bodies; 2 patients: keratitis) were included. Serial AS-OCT and slit-lamp examinations were used to follow up the progress of these patients. The thicknesses of the whole cornea and the corneal stroma were measured with AS-OCT and compared with the findings observed during the slit-lamp examination. RESULTS AS-OCT showed that epithelial hypertrophy and hyperplasia initially occurred in the area of the corneal stromal thinning; subsequently, scar tissue formed in the area with an improvement in the thickness of the corneal stroma. This wound healing process was observed in all 4 patients. The scar tissue initially appeared opaque on slit-lamp examination and was characterized by a high signal produced on AS-OCT, which was different from the normal corneal stroma. The scar tissue gradually appeared clear on slit-lamp examination; however, the high signal on AS-OCT remained. CONCLUSIONS AS-OCT can be used to detect the wound healing process of corneal stromal thinning.
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15
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Boote C, Dooley EP, Gardner SJ, Kamma-Lorger CS, Hayes S, Nielsen K, Hjortdal J, Sorensen T, Terrill NJ, Meek KM. Quantification of collagen ultrastructure after penetrating keratoplasty - implications for corneal biomechanics. PLoS One 2013; 8:e68166. [PMID: 23861866 PMCID: PMC3702563 DOI: 10.1371/journal.pone.0068166] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 05/30/2013] [Indexed: 11/19/2022] Open
Abstract
PURPOSE To quantify long-term changes in stromal collagen ultrastructure following penetrating keratoplasty (PK), and evaluate their possible implications for corneal biomechanics. METHODS A pair of 16 mm post-mortem corneo-scleral buttons was obtained from a patient receiving bilateral penetrating keratoplasty 12 (left)/28 (right) years previously. Small-angle x-ray scattering quantified collagen fibril spacing, diameter and spatial order at 0.5 mm or 0.25 mm intervals along linear scans across the graft margin. Corresponding control data was collected from two corneo-scleral buttons with no history of refractive surgery. Wide-angle x-ray scattering quantified collagen fibril orientation at 0.25 mm (horizontal)×0.25 mm (vertical) intervals across both PK specimens. Quantification of orientation changes in the graft margin were verified by equivalent analysis of data from a 13 year post-operative right PK specimen obtained from a second patient in a previous study, and comparison made with new and published data from normal corneas. RESULTS Marked changes to normal fibril alignment, in favour of tangentially oriented collagen, were observed around the entire graft margin in all PK specimens. The total number of meridional fibrils in the wound margin was observed to decrease by up to 40%, with the number of tangentially oriented fibrils increasing by up to 46%. As a result, in some locations the number of fibrils aligned parallel to the wound outnumbered those spanning it by up to five times. Localised increases in fibril spacing and diameter, with an accompanying reduction in matrix order, were also evident. CONCLUSIONS Abnormal collagen fibril size and spatial order within the PK graft margin are indicative of incomplete stromal wound remodelling and the long term persistence of fibrotic scar tissue. Lasting changes in collagen fibril orientation in and around PK wounds may alter corneal biomechanics and compromise the integrity of the graft-host interface in the long term.
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Affiliation(s)
- Craig Boote
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Erin P. Dooley
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Steven J. Gardner
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Christina S. Kamma-Lorger
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Sally Hayes
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Kim Nielsen
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | - Jesper Hjortdal
- Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark
| | | | | | - Keith M. Meek
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
- * E-mail:
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16
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McGrath LA, Lee GA. Corneal Debridement Update: Adjuvant Therapies and Wound Healing. Asia Pac J Ophthalmol (Phila) 2013; 2:237-43. [PMID: 26106918 DOI: 10.1097/apo.0b013e31829e69b0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Corneal debridement techniques have seen evolution in instrumentation and indication. Although the techniques themselves are simple and usually effective, there is often the need for adjuvant topical therapies to augment healing and/or prevent recurrence of disease. To better understand the requirement for adjuvant therapies, the current theories of corneal wound healing are reviewed.
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Affiliation(s)
- Lindsay A McGrath
- From the *City Eye Centre; †University of Queensland; and ‡Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia
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17
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A microscopy study of the structural features of post-LASIK human corneas. PLoS One 2013; 8:e63268. [PMID: 23650559 PMCID: PMC3641130 DOI: 10.1371/journal.pone.0063268] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 03/30/2013] [Indexed: 11/28/2022] Open
Abstract
Purpose To study the structural features of human post-LASIK corneas. Methods A pair of post-mortem donor corneas, from a 55-year old patient who underwent uncomplicated LASIK surgery five years previously, were bisected and fixed in 4% paraformaldehyde. The right cornea and one half of the left cornea were processed for light microscopy and scanning electron microscopy. One half of the right cornea was also examined by transmission electron microscopy. Results The flap-bed interface could be easily detected several years after LASIK and, although the flap appeared to be in close association with the stromal bed, there was a noticeable absence of reconnection between adjacent severed lamellae. Tissue gaps were evident at the flap margin, which once free of cellular components revealed the presence of a few bridging fibres. Conclusion Examination of corneas five years after LASIK revealed evidence of primitive reparative scar development at the wound interface, but no reconnection of severed collagen lamellae. Such findings may explain the occurrence of flap dislocation following trauma in some patients months or years after surgery.
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18
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Wilson SL, El Haj AJ, Yang Y. Control of scar tissue formation in the cornea: strategies in clinical and corneal tissue engineering. J Funct Biomater 2012; 3:642-87. [PMID: 24955637 PMCID: PMC4031002 DOI: 10.3390/jfb3030642] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 08/27/2012] [Accepted: 08/30/2012] [Indexed: 12/13/2022] Open
Abstract
Corneal structure is highly organized and unified in architecture with structural and functional integration which mediates transparency and vision. Disease and injury are the second most common cause of blindness affecting over 10 million people worldwide. Ninety percent of blindness is permanent due to scarring and vascularization. Scarring caused via fibrotic cellular responses, heals the tissue, but fails to restore transparency. Controlling keratocyte activation and differentiation are key for the inhibition and prevention of fibrosis. Ophthalmic surgery techniques are continually developing to preserve and restore vision but corneal regression and scarring are often detrimental side effects and long term continuous follow up studies are lacking or discouraging. Appropriate corneal models may lead to a reduced need for corneal transplantation as presently there are insufficient numbers or suitable tissue to meet demand. Synthetic optical materials are under development for keratoprothesis although clinical use is limited due to implantation complications and high rejection rates. Tissue engineered corneas offer an alternative which more closely mimic the morphological, physiological and biomechanical properties of native corneas. However, replication of the native collagen fiber organization and retaining the phenotype of stromal cells which prevent scar-like tissue formation remains a challenge. Careful manipulation of culture environments are under investigation to determine a suitable environment that simulates native ECM organization and stimulates keratocyte migration and generation.
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Affiliation(s)
- Samantha L Wilson
- Institute for Science and Technology in Medicine, School of Medicine, Keele University, Staffordshire, ST4 7QB, UK.
| | - Alicia J El Haj
- Institute for Science and Technology in Medicine, School of Medicine, Keele University, Staffordshire, ST4 7QB, UK.
| | - Ying Yang
- Institute for Science and Technology in Medicine, School of Medicine, Keele University, Staffordshire, ST4 7QB, UK.
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Muthusubramaniam L, Peng L, Zaitseva T, Paukshto M, Martin GR, Desai TA. Collagen fibril diameter and alignment promote the quiescent keratocyte phenotype. J Biomed Mater Res A 2011; 100:613-21. [PMID: 22213336 DOI: 10.1002/jbm.a.33284] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 09/26/2011] [Indexed: 11/12/2022]
Abstract
In this study, we investigated how matrix nanotopography affects corneal fibroblast phenotype and matrix synthesis. To this end, corneal fibroblasts isolated from bovine corneas were grown on collagen nanofiber scaffolds of different diameters and alignment--30 nm aligned fibrils (30A), 300 nm or larger aligned fibrils (300A), and 30 nm nonaligned fibrils (30NA) in comparison with collagen coated flat glass substrates (FC). Cell morphology was visualized using confocal microscopy. Quantitative PCR was used to measure expression levels of six target genes: the corneal crystallin-transketolase (TKT), the myofibroblast marker-α-smooth muscle actin (SMA), and four matrix proteins-collagen 1 (COL1), collagen 3 (COL3), fibronectin (FN), and biglycan. It was found that SMA expression was down-regulated and TKT expression was increased on all three collagen nanofiber substrates, compared with the FC control substrates. However, COL3 and biglycan expression was also significantly increased on 300A, compared with the FC substrates. Thus matrix nanotopography down-regulates the fibrotic phenotype, promotes formation of the quiescent keratocyte phenotype, and influences matrix synthesis. These results have significant implications for the engineering of corneal replacements and for promoting regenerative healing of the cornea after disease and/or injury.
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Affiliation(s)
- Lalitha Muthusubramaniam
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94158, USA
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Mi S, Dooley EP, Albon J, Boulton ME, Meek KM, Kamma-Lorger CS. Adhesion of laser in situ keratomileusis–like flaps in the cornea: Effects of crosslinking, stromal fibroblasts, and cytokine treatment. J Cataract Refract Surg 2011; 37:166-72. [PMID: 21183111 DOI: 10.1016/j.jcrs.2010.07.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/13/2010] [Accepted: 07/16/2010] [Indexed: 10/18/2022]
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