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Viehmeister K, Manuelli A, Guerin C, Kappes S, Lamprecht A. Imaging-Based Drug Penetration Profiling in an Excised Sheep Cornea Model. Pharmaceutics 2024; 16:1126. [PMID: 39339164 PMCID: PMC11435002 DOI: 10.3390/pharmaceutics16091126] [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: 06/30/2024] [Revised: 08/04/2024] [Accepted: 08/18/2024] [Indexed: 09/30/2024] Open
Abstract
Formulations designed to address ocular conditions and diseases are predominantly administered topically. While in vitro test systems have been developed to assess corneal permeation under extended contact conditions, methods focusing on determining the penetration depth and kinetics of a substance within the cornea itself rather than through it, are scarce. This study introduces a method for time-dependent penetration depth analysis (10 and 60 min) by means of a semiquantitative imaging method in comparison with a quantitative corneal depth-cut technique, employing fluorescein sodium at concentrations of 0.2 and 0.4 mg/mL as a small molecule model substance and sheep cornea as a human surrogate. Excised tissues exhibited sustained viability in modified artificial aqueous humor and maintained thickness (746 ± 43 µm) and integrity (electrical resistance 488 ± 218 Ω∙cm2) under the experimental conditions. Both methods effectively demonstrated the expected concentration- and time-dependent depth of penetration of fluorescein sodium, displaying a significantly strong correlation. The traceability of the kinetic processes was validated with polysorbate 80, which acted as a penetration enhancer. Furthermore, the imaging-based method enabled detecting the retention of larger structures, such as hyaluronic acid and nanoemulsions from the commercial eyedrop formulation NEOVIS® TOTAL multi, inside the lacrimal layer.
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Affiliation(s)
- Karla Viehmeister
- Department of Pharmaceutics, Institute of Pharmacy, University of Bonn, Gerhard-Domagk-Str. 3, 53121 Bonn, Germany
| | - Aurélie Manuelli
- Horus Pharma, 22, Allée Camille Muffat, Inedi 5, 06200 Nice, France
| | - Camille Guerin
- Horus Pharma, 22, Allée Camille Muffat, Inedi 5, 06200 Nice, France
| | - Sebastian Kappes
- Department of Pharmaceutics, Institute of Pharmacy, University of Bonn, Gerhard-Domagk-Str. 3, 53121 Bonn, Germany
| | - Alf Lamprecht
- Department of Pharmaceutics, Institute of Pharmacy, University of Bonn, Gerhard-Domagk-Str. 3, 53121 Bonn, Germany
- Université de Franche-Comté, INSERM UMR1098 Right, 25030 Besançon, France
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2
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Pilotaz F, Loftsson T. Aqueous eye drop formulations: Cyclodextrins as enabling excipients. ANNALES PHARMACEUTIQUES FRANÇAISES 2024:S0003-4509(24)00110-X. [PMID: 39127321 DOI: 10.1016/j.pharma.2024.08.003] [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: 06/16/2024] [Revised: 07/30/2024] [Accepted: 08/06/2024] [Indexed: 08/12/2024]
Abstract
Cyclodextrins are enabling pharmaceutical excipients that solubilize and stabilize drugs in aqueous formulations. Cyclodextrins possess very favorable pharmacokinetic and toxicological profiles and are commonly used in marketed drug products for oral and parenteral administration. However, their use in ophthalmic products is still very limited. Cyclodextrins have a broad range of physical properties that are specifically appropriate for designing topical ophthalmic dosage forms. Additionally, both the regulatory and intellectual property environments have been cleared over the last years and should foster their use for designing new drugs for ophthalmic use.
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Affiliation(s)
- Frédéric Pilotaz
- Horus-Pharma, Département des Opérations Industrielles, 22, allée Camille-Muffat, bât. Inedi 5, 06200 Nice, France.
| | - Thorsteinn Loftsson
- Faculty of Pharmaceutical Sciences, School of Health Sciences, University of Iceland, Hofsvallagata 53, 107 Reykjavik, Iceland
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3
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Bergmanson JPG, Burns AR, Walker MK. Central versus peripheral thickness in the human cornea explained. Cont Lens Anterior Eye 2024; 47:102165. [PMID: 38589268 DOI: 10.1016/j.clae.2024.102165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/29/2024] [Accepted: 04/03/2024] [Indexed: 04/10/2024]
Abstract
PURPOSE The human cornea is thicker in the periphery than the center and it has been suggested that this must be due to greater numbers of lamellae in the peripheral corneal stroma. The purpose of this study was to use high-resolution ultrastructural imaging to determine if the greater thickness of the peripheral cornea is due to the presence of more lamellae or if there is some other anatomical explanation. METHODS In this study, full thickness corneas from three human donors were processed for light microscopy (LM) and transmission electron microscopy (TEM). Images were taken in three distinct stromal regions (anterior, middle, and posterior) from the central and peripheral cornea. Stromal thickness was evaluated by LM while TEM was used to evaluate numbers and thicknesses of lamellae, mean collagen fibril diameter, and mean collagen fibril density. RESULTS Mean stromal thickness was significantly thinner in the central (415 ± 34 µm) compared to the peripheral (536 ± 29 µm) cornea (P = 0.009). Numbers of lamellae were not significantly different between central (246 ± 14) and peripheral (251 ± 14) cornea. Average lamellar thickness was not different across all regions of the cornea, except for the peripheral posterior where the lamellae were approximately 50 % thicker (P < 0.05). Collagen fibril diameters were larger in the peripheral cornea by approximately 30 % when compared to the central cornea, in all regions (P < 0.01). CONCLUSIONS This study shows that it is an increase peripheral posterior lamellar thickness, rather than an increase in the number of lamellae, that accounts for the increase in corneal stromal thickness in the periphery of the human cornea. While collagen fibril diameters are greater throughout the peripheral stroma, the lamellae in the mid and anterior peripheral stroma are not thicker than centrally.
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Affiliation(s)
- Jan P G Bergmanson
- University of Houston, College of Optometry, Texas Eye Research & Technology Center, 4401 Martin Luther King Boulevard, Houston, TX 77204-2020, United States.
| | - Alan R Burns
- University of Houston, College of Optometry, Texas Eye Research & Technology Center, 4401 Martin Luther King Boulevard, Houston, TX 77204-2020, United States
| | - Maria K Walker
- University of Houston, College of Optometry, Texas Eye Research & Technology Center, 4401 Martin Luther King Boulevard, Houston, TX 77204-2020, United States
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4
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Yaylacıoğlu Tuncay F, Talim B, Dinçer PR. Mimicking TGFBI Hot-Spot Mutation Did Not Result in Any Deposit Formation in the Zebrafish Cornea. Curr Eye Res 2024; 49:458-466. [PMID: 38164916 DOI: 10.1080/02713683.2023.2298904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 12/16/2023] [Indexed: 01/03/2024]
Abstract
PURPOSE Mutations in transforming growth factor beta-induced (TGFBI) protein are associated with a group of corneal dystrophies (CDs), classified as TGFBI-associated CDs, characterized by deposits in the cornea. Mouse models were not proper in several aspects for modelling human disease. The goal of this study was to generate zebrafish mutants to investigate the corneal phenotype and to decide whether zebrafish could be a potential model for TGFBI-associated CDs. METHODS The conserved arginine residue, codon 117, in zebrafish tgfbi gene was targeted with Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 method. Cas9 VQR variant was used with two target-specific sgRNAs to generate mutations. The presence of mutations was evaluated by T7 Endonuclease Enzyme (T7EI) assay and the type of the mutations were evaluated by Sanger sequencing. The mutant zebrafish at 3 months and 1 year of age were investigated under the microscope for corneal opacity and eye sections were evaluated histopathologically with hematoxylin-eosin, masson-trichrome and congo red stains for corneal deposits. RESULTS We achieved indel variation at the target sequence that resulted in p.Ser115_Arg117delinsLeu (c. 347_353delinsT) by nonhomology mediated repair in F1. This zebrafish mutation had the potential to mimic two disease-causing mutations reported in human cases previously: R124L and R124L + del125-126. Mutant zebrafish did not show any corneal opacity or corneal deposits at 3 months and 1 year of age. CONCLUSION This study generated the first zebrafish model mimicking the R124 hot spot mutation in TGFBI-associated CDs. However, evaluations even at 1 year of age did not reveal any deposits in the cornea histopathologically. This study increased the cautions for modelling TGFBI-associated CDs in zebrafish in addition to differences in the corneal structure between zebrafish and humans.
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Affiliation(s)
- Fulya Yaylacıoğlu Tuncay
- Medical Biology, Gülhane Medical Faculty, University of Health Sciences, Ankara, Turkey
- Medical Biology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Beril Talim
- Pathology Unit, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
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5
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Barry Collin H, Ratcliffe J, Collin SP. Morphology of the cornea and iris in the Australian lungfish Neoceratodus forsteri (Krefft 1870) (Dipnoi): Functional and evolutionary perspectives of transitioning from an aquatic to a terrestrial environment. J Morphol 2024; 285:e21662. [PMID: 38100743 DOI: 10.1002/jmor.21662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 11/26/2023] [Accepted: 11/29/2023] [Indexed: 12/17/2023]
Abstract
The Australian lungfish, Neoceratodus forsteri (Krefft 1870), is the sole extant member of the Ceratodontidae within the Dipnoi, a small order of sarcopterygian (lobe-finned) fishes, that is thought to be the earliest branching species of extant lungfishes, having changed little over the last 100 million years. To extend studies on anatomical adaptations associated with the fish-tetrapod transition, the ultrastructure of the cornea and iris is investigated using light and electron (transmission and scanning) microscopy to investigate structure-function relationships and compare these to other vertebrate corneas (other fishes and tetrapods). In contrast to previous studies, the cornea is found to have only three main components, comprising an epithelium with its basement membrane, a stroma with a Bowman's layer and an endothelium, and is not split into a dermal (secondary) spectacle and a scleral cornea. The epithelial cells are large, relatively low in density and similar to many species of non-aquatic tetrapods and uniquely possess numerous surface canals that contain and release mucous granules onto the corneal surface to avoid desiccation. A Bowman's layer is present and, in association with extensive branching and anastomosing of the collagen fibrils, may be an adaptation for the inhibition of swelling and/or splitting of the stroma during its amphibious lifestyle. The dorsal region of the stroma possesses aggregations of pigment granules that act as a yellow, short wavelength-absorbing filter during bright light conditions. Desçemet's membrane is absent and replaced by an incomplete basement membrane overlying a monocellular endothelium. The iris is pigmented, well-developed, vascularised and contractile containing reflective crystals anteriorly. Based upon its ultrastructure and functional adaptations, the cornea of N. forsteri is more similar to amphibians than to other bony fishes and is well-adapted for an amphibious lifestyle.
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Affiliation(s)
- Hermann Barry Collin
- Department of Optometry and Vision Science, University of New South Wales, Kensington, New South Wales, Australia
| | - Julian Ratcliffe
- Bioimaging Platform, La Trobe University, Bundoora, Victoria, Australia
| | - Shaun P Collin
- School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, Victoria, Australia
- Oceans Graduate School and Oceans Institute, The University of Western Australia, Crawley, Western Australia, Australia
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Tarvestad-Laise KE, Ceresa BP. Modulating Growth Factor Receptor Signaling to Promote Corneal Epithelial Homeostasis. Cells 2023; 12:2730. [PMID: 38067157 PMCID: PMC10706396 DOI: 10.3390/cells12232730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/20/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
The corneal epithelium is the first anatomical barrier between the environment and the cornea; it is critical for proper light refraction onto the retina and prevents pathogens (e.g., bacteria, viruses) from entering the immune-privileged eye. Trauma to the highly innervated corneal epithelium is extremely painful and if not resolved quickly or properly, can lead to infection and ultimately blindness. The healthy eye produces its own growth factors and is continuously bathed in tear fluid that contains these proteins and other nutrients to maintain the rapid turnover and homeostasis of the ocular surface. In this article, we review the roles of growth factors in corneal epithelial homeostasis and regeneration and some of the limitations to their use therapeutically.
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Affiliation(s)
- Kate E. Tarvestad-Laise
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY 40202, USA
| | - Brian P. Ceresa
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY 40202, USA
- Department of Ophthalmology and Vision Sciences, University of Louisville, Louisville, KY 40202, USA
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Lan G, Twa MD, Song C, Feng J, Huang Y, Xu J, Qin J, An L, Wei X. In vivo corneal elastography: A topical review of challenges and opportunities. Comput Struct Biotechnol J 2023; 21:2664-2687. [PMID: 37181662 PMCID: PMC10173410 DOI: 10.1016/j.csbj.2023.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/07/2023] [Accepted: 04/12/2023] [Indexed: 05/16/2023] Open
Abstract
Clinical measurement of corneal biomechanics can aid in the early diagnosis, progression tracking, and treatment evaluation of ocular diseases. Over the past two decades, interdisciplinary collaborations between investigators in optical engineering, analytical biomechanical modeling, and clinical research has expanded our knowledge of corneal biomechanics. These advances have led to innovations in testing methods (ex vivo, and recently, in vivo) across multiple spatial and strain scales. However, in vivo measurement of corneal biomechanics remains a long-standing challenge and is currently an active area of research. Here, we review the existing and emerging approaches for in vivo corneal biomechanics evaluation, which include corneal applanation methods, such as ocular response analyzer (ORA) and corneal visualization Scheimpflug technology (Corvis ST), Brillouin microscopy, and elastography methods, and the emerging field of optical coherence elastography (OCE). We describe the fundamental concepts, analytical methods, and current clinical status for each of these methods. Finally, we discuss open questions for the current state of in vivo biomechanics assessment techniques and requirements for wider use that will further broaden our understanding of corneal biomechanics for the detection and management of ocular diseases, and improve the safety and efficacy of future clinical practice.
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Affiliation(s)
- Gongpu Lan
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Michael D. Twa
- College of Optometry, University of Houston, Houston, TX 77204, United States
| | - Chengjin Song
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
| | - JinPing Feng
- Institute of Engineering and Technology, Hubei University of Science and Technology, Xianning, Hubei 437100, China
| | - Yanping Huang
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Jingjiang Xu
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Jia Qin
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Lin An
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Xunbin Wei
- Biomedical Engineering Department, Peking University, Beijing 100081, China
- International Cancer Institute, Peking University, Beijing 100191, China
- Institute of Medical Technology, Peking University Health Science Center, Beijing 100191, China
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8
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Uzel E, Durgun ME, Esentürk-Güzel İ, Güngör S, Özsoy Y. Nanofibers in Ocular Drug Targeting and Tissue Engineering: Their Importance, Advantages, Advances, and Future Perspectives. Pharmaceutics 2023; 15:pharmaceutics15041062. [PMID: 37111550 PMCID: PMC10145046 DOI: 10.3390/pharmaceutics15041062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/17/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023] Open
Abstract
Nanofibers are frequently encountered in daily life as a modern material with a wide range of applications. The important advantages of production techniques, such as being easy, cost effective, and industrially applicable are important factors in the preference for nanofibers. Nanofibers, which have a broad scope of use in the field of health, are preferred both in drug delivery systems and tissue engineering. Due to the biocompatible materials used in their construction, they are also frequently preferred in ocular applications. The fact that they have a long drug release time as a drug delivery system and have been used in corneal tissue studies, which have been successfully developed in tissue engineering, stand out as important advantages of nanofibers. This review examines nanofibers, their production techniques and general information, nanofiber-based ocular drug delivery systems, and tissue engineering concepts in detail.
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Affiliation(s)
- Egemen Uzel
- Institute of Graduate Studies in Health Sciences, Istanbul University, Istanbul 34010, Türkiye
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Istanbul University, Istanbul 34126, Türkiye
| | - Meltem Ezgi Durgun
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Istanbul University, Istanbul 34126, Türkiye
| | - İmren Esentürk-Güzel
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Health Sciences, Istanbul 34668, Türkiye
| | - Sevgi Güngör
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Istanbul University, Istanbul 34126, Türkiye
| | - Yıldız Özsoy
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Istanbul University, Istanbul 34126, Türkiye
- Correspondence: ; Tel.: +90-212-4400000 (ext. 13498)
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Balters L, Reichl S. 3D bioprinting of corneal models: A review of the current state and future outlook. J Tissue Eng 2023; 14:20417314231197793. [PMID: 37719307 PMCID: PMC10504850 DOI: 10.1177/20417314231197793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/13/2023] [Indexed: 09/19/2023] Open
Abstract
The cornea is the outermost layer of the eye and serves to protect the eye and enable vision by refracting light. The need for cornea organ donors remains high, and the demand for an artificial alternative continues to grow. 3D bioprinting is a promising new method to create artificial organs and tissues. 3D bioprinting offers the precise spatial arrangement of biomaterials and cells to create 3D constructs. As the cornea is an avascular tissue which makes it more attractive for 3D bioprinting, it could be one of the first tissues to be made fully functional via 3D bioprinting. This review discusses the most common 3D bioprinting technologies and biomaterials used for 3D bioprinting corneal models. Additionally, the current state of 3D bioprinted corneal models, especially specific characteristics such as light transmission, biomechanics, and marker expression, and in vivo studies are discussed. Finally, the current challenges and future prospects are presented.
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Affiliation(s)
- Leon Balters
- Institute of Pharmaceutical Technology and Biopharmaceutics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Stephan Reichl
- Institute of Pharmaceutical Technology and Biopharmaceutics, Technische Universität Braunschweig, Braunschweig, Germany
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Hu W, Mu Y, Lin F, Li X, Zhang J. New Insight Into Visual Adaptation in the Mudskipper Cornea: From Morphology to the Cornea-Related COL8A2 Gene. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.871370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Much research has focused on visual system evolution in bony fishes. The capacity of visual systems to perceive and respond to external signals is integral to evolutionary success. However, integrated research on the mechanisms of adaptive evolution based on corneal structure and related genes remains limited. In this study, scanning electron microscopy (SEM) was used to assess the microstructure and adaptation of corneal epithelial cells. Then, the evolution of the cornea-related COL8A2 gene was investigated. We found various projections (microridges, microplicae, microholes, and microvilli) on the corneal epithelial cells of amphibious mudskippers. Compared with those of fully aquatic fishes, these microstructures were considered adaptations to the variable environments experienced by amphibious mudskippers, as they can resist dryness in terrestrial environments and infection in aquatic environments. Moreover, strong purifying selection was detected for COL8A2. In addition, some specific amino acid substitution sites were also identified in the COL8A2 sequence in mudskippers. Interestingly, the evolutionary rate of the COL8A2 gene was significantly and positively correlated with maximum diving depth in our dataset. Specifically, with increasing diving depth, the evolutionary rate of the COL8A2 gene seemed to gradually accelerate. The results indicated that the cornea of bony fishes has evolved through adaptation to cope with the different diving depths encountered during the evolutionary process, with the corneal evolution of the amphibious mudskipper group showing a unique pattern.
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de Barros MRM, Chakravarti S. Pathogenesis of keratoconus: NRF2-antioxidant, extracellular matrix and cellular dysfunctions. Exp Eye Res 2022; 219:109062. [PMID: 35385756 DOI: 10.1016/j.exer.2022.109062] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/19/2022] [Accepted: 03/30/2022] [Indexed: 11/04/2022]
Abstract
Keratoconus (KC) is a degenerative disease associated with cell and extracellular matrix (ECM) loss that causes gradual thinning and steepening of the cornea and loss of vision. Collagen cross linking with ultraviolet light treatment can strengthen the ECM and delay weakening of the cornea, but severe cases require corneal transplantation. KC is multifactorial and multigenic, but its pathophysiology is still an enigma. Multiple approaches are being pursued to elucidate the molecular changes that underlie the corneal phenotype to identify relevant genes for tailored candidate searches and to develop potential biomarkers and targets for therapeutic interventions. Recent proteomic and transcriptomic studies suggest dysregulations in oxidative stress, NRF2-regulated antioxidant programs, WNT-signaling, TGF-β, ECM and matrix metalloproteinases. This review aims to provide a broad update on the transcriptomic and proteomic studies of KC with a focus on findings that relate to oxidative stress, and dysregulations in cellular and extracellular matrix functions.
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Affiliation(s)
| | - Shukti Chakravarti
- Department of Ophthalmology, NYU Grossman School of Medicine, NY, 10016, USA; Department of Pathology, NYU Grossman School of Medicine, NY, 10016, USA.
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12
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Acri G, Micali A, D’Angelo R, Puzzolo D, Aragona P, Testagrossa B, Aragona E, Wylegala E, Nowinska A. Raman Spectroscopic Study of Amyloid Deposits in Gelatinous Drop-like Corneal Dystrophy. J Clin Med 2022; 11:jcm11051403. [PMID: 35268494 PMCID: PMC8911144 DOI: 10.3390/jcm11051403] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/12/2022] [Accepted: 03/02/2022] [Indexed: 02/07/2023] Open
Abstract
The genetic and histopathological features of the cornea of a Polish patient with Gelatinous Drop-like Corneal Dystrophy (GDCD) and the molecular composition with Raman spectroscopy of corneal deposits were examined. A 62 year-old Polish woman was diagnosed with GDCD and underwent penetrating corneal transplant. A blood sample was collected, and genetic analysis was performed. The cornea was processed for light microscopy and Raman analysis. The genetic exam revealed a previously undescribed homozygous 1-base pair deletion in exon 1 of TACSTD2 gene (c.185delT), resulting in a frame shift causing a premature stop codon. When compared with a control cornea, in GDCD cornea stained with PAS evident deposits were present over the anterior stroma, with apple green birefringence under polarized light. Raman spectroscopy showed peculiar differences between normal and GDCD cornea, consisting in peaks either of different height or undetectable in the normal cornea and related to amyloid. The possible causative role of the novel mutation was discussed and Raman spectroscopy as a further morphological tool in the evaluation of corneal dystrophies, characterized by the deposition of abnormal materials, was suggested.
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Affiliation(s)
- Giuseppe Acri
- Department of Biomedical Sciences, Section of Physics, University of Messina, 98125 Messina, Italy; (G.A.); (B.T.)
| | - Antonio Micali
- Department of Adult and Pediatric Pathology, University of Messina, 98125 Messina, Italy
- Correspondence: ; Tel.: +39-90-2213630
| | - Rosalia D’Angelo
- Department of Biomedical Sciences, Section of Biology and Genetics, University of Messina, 98125 Messina, Italy;
| | - Domenico Puzzolo
- Department of Biomedical Sciences, Section of Histology and Embryology, University of Messina, 98125 Messina, Italy;
| | - Pasquale Aragona
- Department of Biomedical Sciences, Eye Clinic, Regional Referral Center for the Ocular Surface Diseases, University of Messina, 98125 Messina, Italy;
| | - Barbara Testagrossa
- Department of Biomedical Sciences, Section of Physics, University of Messina, 98125 Messina, Italy; (G.A.); (B.T.)
| | - Emanuela Aragona
- Department of Ophthalmology, Scientific Institute San Raffaele, Vita-Salute University, 20132 Milan, Italy;
| | - Edward Wylegala
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-555 Katowice, Poland; (E.W.); (A.N.)
- Ophthalmology Department, Railway Hospital, 40-760 Katowice, Poland
| | - Anna Nowinska
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-555 Katowice, Poland; (E.W.); (A.N.)
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Abstract
INTRODUCTION Retinal diseases are one of the main reasons for vision loss where all available drug treatments are based on invasive drug administration such as intravitreal injections. Despite huge efforts and some promising results in animal models, almost all delivery technologies tested have failed in human trials. There are however examples of clinically effective topical delivery systems such as fast dissolving aqueous eye drop suspensions. AREAS COVERED Six obstacles to topical drug delivery to the eye have been identified and discussed in some details. These obstacles consist of static membrane barriers to drug permeation into the eye, dynamic barriers such as the lacrimal drainage and physiochemical barriers such as low thermodynamic activity. It is explained how and why these obstacles hamper drug permeation and how different technologies, both those that are applied in marketed drug products and those that are under investigation, have addressed these obstacles. EXPERT OPINION The reason that most topical drug delivery systems have failed to deliver therapeutic drug concentrations to the retina is that they do not address physiochemical barriers such as the thermodynamic activity of the permeating drug molecules. Topical drug delivery to the retina has only been successful when the static, dynamic, and physiochemical barriers are addressed simultaneously.
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Affiliation(s)
- Thorsteinn Loftsson
- Faculty of Pharmaceutical Sciences, University of Iceland, Reykjavik, Iceland
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Cheng G, Chen L, Feng H, Jiang B, Ding Y. Preliminary Study on Fish Scale Collagen Lamellar Matrix as Artificial Cornea. MEMBRANES 2021; 11:737. [PMID: 34677503 PMCID: PMC8540030 DOI: 10.3390/membranes11100737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 06/14/2021] [Accepted: 06/15/2021] [Indexed: 11/16/2022]
Abstract
To construct a novel artificial cornea biomaterial, a method to prepare collagen lamellar matrix was developed in this study using grass carp scales as raw materials. The relationship between the structure of fish scale collagen lamellar matrix and the optical and mechanical properties was analyzed, and co-culture of it and rat bone marrow mesenchymal stem cells (BMSCs) was performed to preliminarily analyze the cellular compatibility of fish scale collagen lamellar matrix. The results show that the grass carp scales could be divided into base region, lateral region and parietal region according to the surface morphology. The inorganic calcium in the surface layer could be effectively removed by decalcification, and the decalcification rate could reach 99%. After etching treatment, homogeneous collagen lamellar matrix could be obtained. With the decalcification and etching treatment, the water content of the sample increased gradually, but the cross-linking treatment had no obvious effect on the water content of fish scale collagen lamellar matrix. Fish scale collagen lamellar matrix has good transparency, refractive index, mechanical properties and cellular compatibility, which may represent a prospect for the construction of cornea tissue engineering products.
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Affiliation(s)
- Guoping Cheng
- Department of Periodontics, West China College of Stomatology, Sichuan University, Chengdu 610041, China; (G.C.); (L.C.)
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041, China
| | - Liang Chen
- Department of Periodontics, West China College of Stomatology, Sichuan University, Chengdu 610041, China; (G.C.); (L.C.)
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041, China
| | - Huanhuan Feng
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610041, China;
| | - Bo Jiang
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610041, China;
| | - Yi Ding
- Department of Periodontics, West China College of Stomatology, Sichuan University, Chengdu 610041, China; (G.C.); (L.C.)
- State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041, China
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15
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Wang R, Lu D, Wang H, Zou H, Bai T, Feng C, Lin Q. "Kill-release" antibacterial polysaccharides multilayer coating based therapeutic contact lens for effective bacterial keratitis treatment. RSC Adv 2021; 11:26160-26167. [PMID: 35479473 PMCID: PMC9037525 DOI: 10.1039/d1ra02472h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/24/2021] [Indexed: 01/06/2023] Open
Abstract
Contact lenses (CLs) are an important medical device for ophthalmic disease treatment. They can be used not only to correct refractive errors, such as myopia, but also can serve as a drug carrier for ocular surface disease treatment. In this study, a therapeutic CL was designed for bacterial keratitis treatment by constructing an antibacterial surface coating via a layer-by-layer (LbL) electrostatic self-assembly method. Vancomycin-incorporated chitosan nanoparticles were firstly prepared by ionic condensation of sodium tripolyphosphate (abbreviated as CTVNP). The positively charged CTVNP were then used for LbL deposition with negatively charged heparin (HEP), obtaining a (HEP/CTVNP)n polyelectrolyte multilayer on the CL surface. It is shown that such antibiotic incorporated surface coating doesn't influence the light transmittance of the CL, so it should not affect the patients' visual acuity when wearing them. The in vitro bacteriostatic effect evaluation was performed via live and dead bacteria staining and scanning electron microscope (SEM), which demonstrated the effective antibacterial property of such a surface. The fabricated therapeutic CL was then used to treat bacterial keratitis on a rabbit model. The results showed that such CL could effectively control the development of the bacteria-infected cornea and had a significant therapeutic effect. Therapeutic contact lenses fabricated by polysaccharides multilayer surface modification, shows “kill-release” antibacterial performance, can serve as an effective treatment for bacterial keratitis.![]()
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Affiliation(s)
- Rui Wang
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University 270 Xueyuan Road Wenzhou 325027 China
| | - Duoduo Lu
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University 270 Xueyuan Road Wenzhou 325027 China
| | - Hui Wang
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University 270 Xueyuan Road Wenzhou 325027 China
| | - Haoyu Zou
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University 270 Xueyuan Road Wenzhou 325027 China
| | - Ting Bai
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University 270 Xueyuan Road Wenzhou 325027 China
| | - Chulei Feng
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University 270 Xueyuan Road Wenzhou 325027 China
| | - Quankui Lin
- School of Ophthalmology & Optometry, Eye Hospital, Wenzhou Medical University 270 Xueyuan Road Wenzhou 325027 China
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16
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Sterenczak KA, Winter K, Sperlich K, Stahnke T, Linke S, Farrokhi S, Klemm M, Allgeier S, Köhler B, Reichert KM, Guthoff RF, Bohn S, Stachs O. Morphological characterization of the human corneal epithelium by in vivo confocal laser scanning microscopy. Quant Imaging Med Surg 2021; 11:1737-1750. [PMID: 33936961 DOI: 10.21037/qims-20-1052] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Background Regarding the growing interest and importance of understanding the cellular changes of the cornea in diseases, a quantitative cellular characterization of the epithelium is becoming increasingly important. Towards this, the latest research offers considerable improvements in imaging of the cornea by confocal laser scanning microscopy (CLSM). This study presents a pipeline to generate normative morphological data of epithelial cell layers of healthy human corneas. Methods 3D in vivo CLSM was performed on the eyes of volunteers (n=25) with a Heidelberg Retina Tomograph II equipped with an in-house modified version of the Rostock Cornea Module implementing two dedicated piezo actuators and a concave contact cap. Image data were acquired with nearly isotropic voxel resolution. After image registration, stacks of en-face sections were used to generate full-thickness volume data sets of the epithelium. Beyond that, an image analysis algorithm quantified en-face sections of epithelial cells regarding the depth-dependent mean of cell density, area, diameter, aggregation (Clark and Evans index of aggregation), neighbor count and polygonality. Results Imaging and cell segmentation were successfully performed in all subjects. Thereby intermediated cells were efficiently recognized by the segmentation algorithm while efficiency for superficial and basal cells was reduced. Morphological parameters showed an increased mean cell density, decreased mean cell area and mean diameter from anterior to posterior (5,197.02 to 8,190.39 cells/mm2; 160.51 to 90.29 µm2; 15.9 to 12.3 µm respectively). Aggregation gradually increased from anterior to posterior ranging from 1.45 to 1.53. Average neighbor count increased from 5.50 to a maximum of 5.66 followed by a gradual decrease to 5.45 within the normalized depth from anterior to posterior. Polygonality gradually decreased ranging from 4.93 to 4.64 sides of cells. The neighbor count and polygonality parameters exhibited profound depth-dependent changes. Conclusions This in vivo study demonstrates the successful implementation of a CLSM-based imaging pipeline for cellular characterization of the human corneal epithelium. The dedicated hardware in combination with an adapted image registration method to correct the remaining motion-induced image distortions followed by a dedicated algorithm to calculate characteristic quantities of different epithelial cell layers enabled the generation of normative data. Further significant effort is necessary to improve the algorithm for superficial and basal cell segmentation.
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Affiliation(s)
| | - Karsten Winter
- Institute of Anatomy, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Karsten Sperlich
- Department of Ophthalmology, Rostock University Medical Center, Rostock, Germany.,Department Life, Light & Matter, University of Rostock, Rostock, Germany
| | - Thomas Stahnke
- Department of Ophthalmology, Rostock University Medical Center, Rostock, Germany.,Department Life, Light & Matter, University of Rostock, Rostock, Germany
| | - Stephan Linke
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Zentrumsehstärke, Hamburg, Germany
| | - Sanaz Farrokhi
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Maren Klemm
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Stephan Allgeier
- Institute for Automation and Applied Informatics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Bernd Köhler
- Institute for Automation and Applied Informatics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Klaus-Martin Reichert
- Institute for Automation and Applied Informatics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Rudolf F Guthoff
- Department of Ophthalmology, Rostock University Medical Center, Rostock, Germany.,Department Life, Light & Matter, University of Rostock, Rostock, Germany
| | - Sebastian Bohn
- Department of Ophthalmology, Rostock University Medical Center, Rostock, Germany.,Department Life, Light & Matter, University of Rostock, Rostock, Germany
| | - Oliver Stachs
- Department of Ophthalmology, Rostock University Medical Center, Rostock, Germany.,Department Life, Light & Matter, University of Rostock, Rostock, Germany
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17
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Doughty MJ, Bergmanson JPG. Collagen fibril characteristics at the corneo‐scleral boundary and rabbit corneal stromal swelling. Clin Exp Optom 2021; 87:81-92. [PMID: 15040774 DOI: 10.1111/j.1444-0938.2004.tb03153.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2003] [Revised: 10/29/2003] [Accepted: 11/11/2003] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND The aim of this investigation was to reassess the impact of the scleral rim on the swelling of the mammalian corneal stroma and to investigate the ultrastructural features of the scleral rim and corneal stromal tissues. METHODS The epithelium and endothelium were removed from corneas excised from three-month-old female rabbits. The resulting preparations consisted of the corneal stroma plus a surrounding scleral rim, excised corneal stroma or a nine-millimetre button of central corneal stroma. These preparations were immersed in a 35 mM bicarbonate-buffered mixed salt solution (equilibrated with five per cent CO2-air, pH 7.54 at 37 degrees Centigrade for nine hours. Some sclero-corneal preparations were fixed for light or transmission electron microscopy. RESULTS The initial rate of swelling of corneal stromal buttons was greatest at 127 +/- 8 per cent per hour, less for complete stromal preparations (118 +/- 9 per cent per hour) and least for sclero-stromal preparations (76 +/- 12 per cent per hour). The swelling continued over three to nine hours but sclera preparations swelled up to 40 per cent with no further swelling. Light microscopy demonstrated that the sclero-corneal rim tissue limited the swelling of the posterior corneal stroma. TEM sections of the episclera and sclera indicate that most fibril bundles show a radial orientation to the cornea. There are marked anterio-posterior differences in the collagen fibrils of the scleral surround that are distinctly different from previous reports. Average fibril diameters were 62.8 +/- 7.9 nm in the episclera, 122.4 +/- 18.9 nm, 133.5 +/- 51.9 nm and 56.5 +/- 11.2 nm in the anterior, mid- and posterior scleral stroma, compared to an average fibril diameter of 33.5 +/- 3.5 nm for the posterior corneal stroma. CONCLUSIONS When there is a scleral rim in place, the swelling of the corneal stroma is substantially less than for isolated corneal stroma. The effect can be attributed to the absence of a cut-edge effect for the sclero-corneal stromal preparation but the unique and largely radial arrangement of the collagen fibrils in the scleral rim plays a part in limiting the swelling of the adjacent corneal stroma. The heterogeneous nature of this sclero-corneal interface requires further investigation to define the mechanism of the effect.
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Affiliation(s)
- Michael J Doughty
- Department of Vision Sciences, Glasgow-Caledonian University, Glasgow, United Kingdom
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18
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Hasenzahl M, Müsken M, Mertsch S, Schrader S, Reichl S. Cell sheet technology: Influence of culture conditions on in vitro-cultivated corneal stromal tissue for regenerative therapies of the ocular surface. J Biomed Mater Res B Appl Biomater 2021; 109:1488-1504. [PMID: 33538123 DOI: 10.1002/jbm.b.34808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 01/11/2021] [Accepted: 01/14/2021] [Indexed: 11/11/2022]
Abstract
The in vitro reconstruction of stromal tissue by long-term cultivation of corneal fibroblasts is a smart approach for regenerative therapies of ocular surface diseases. However, systematic investigations evaluating optimized cultivation protocols for the realization of a biomaterial are lacking. This study investigated the influence of supplements to the culture media of human corneal fibroblasts on the formation of a cell sheet consisting of cells and extracellular matrix. Among the supplements studied are vitamin C, fetal bovine serum, L-glutamine, components of collagen such as L-proline, L-4-hydroxyproline and glycine, and TGF-β1, bFGF, IGF-2, PDGF-BB and insulin. After long-term cultivation, the proliferation, collagen and glycosaminoglycan content and light transmission of the cell sheets were examined. Biomechanical properties were investigated by tensile tests and the ultrastructure was characterized by electron microscopy, small-angle X-ray scattering, antibody staining and ELISA. The synthesis of extracellular matrix was significantly increased by cultivation with insulin or TGF-β1, each with vitamin C. The sheets exhibited a high transparency and suitable material properties. The production of a transparent, scaffold-free, potentially autologous, in vitro-generated construct by culturing fibroblasts with extracellular matrix synthesis-stimulating supplements represents a promising approach for a biomaterial that can be used for ocular surface reconstruction in slowly progressing diseases.
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Affiliation(s)
- Meike Hasenzahl
- Institut für Pharmazeutische Technologie, Technische Universität Braunschweig, Braunschweig, Germany
| | - Mathias Müsken
- Helmholtz-Centre for Infection Research, Central Facility for Microscopy, Braunschweig, Germany
| | - Sonja Mertsch
- Laboratory of Experimental Ophthalmology, Department of Ophthalmology, Pius-Hospital, Carl von Ossietzky University, Oldenburg, Germany
| | - Stefan Schrader
- Laboratory of Experimental Ophthalmology, Department of Ophthalmology, Pius-Hospital, Carl von Ossietzky University, Oldenburg, Germany
| | - Stephan Reichl
- Institut für Pharmazeutische Technologie, Technische Universität Braunschweig, Braunschweig, Germany
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Guérin LP, Le-Bel G, Desjardins P, Couture C, Gillard E, Boisselier É, Bazin R, Germain L, Guérin SL. The Human Tissue-Engineered Cornea (hTEC): Recent Progress. Int J Mol Sci 2021; 22:ijms22031291. [PMID: 33525484 PMCID: PMC7865732 DOI: 10.3390/ijms22031291] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 12/11/2022] Open
Abstract
Each day, about 2000 U.S. workers have a job-related eye injury requiring medical treatment. Corneal diseases are the fifth cause of blindness worldwide. Most of these diseases can be cured using one form or another of corneal transplantation, which is the most successful transplantation in humans. In 2012, it was estimated that 12.7 million people were waiting for a corneal transplantation worldwide. Unfortunately, only 1 in 70 patients received a corneal graft that same year. In order to provide alternatives to the shortage of graftable corneas, considerable progress has been achieved in the development of living corneal substitutes produced by tissue engineering and designed to mimic their in vivo counterpart in terms of cell phenotype and tissue architecture. Most of these substitutes use synthetic biomaterials combined with immortalized cells, which makes them dissimilar from the native cornea. However, studies have emerged that describe the production of tridimensional (3D) tissue-engineered corneas using untransformed human corneal epithelial cells grown on a totally natural stroma synthesized by living corneal fibroblasts, that also show appropriate histology and expression of both extracellular matrix (ECM) components and integrins. This review highlights contributions from laboratories working on the production of human tissue-engineered corneas (hTECs) as future substitutes for grafting purposes. It overviews alternative models to the grafting of cadaveric corneas where cell organization is provided by the substrate, and then focuses on their 3D counterparts that are closer to the native human corneal architecture because of their tissue development and cell arrangement properties. These completely biological hTECs are therefore very promising as models that may help understand many aspects of the molecular and cellular mechanistic response of the cornea toward different types of diseases or wounds, as well as assist in the development of novel drugs that might be promising for therapeutic purposes.
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Affiliation(s)
- Louis-Philippe Guérin
- CUO-Recherche, Médecine Régénératrice—Centre de Recherche du CHU de Québec, Université Laval, Québec, QC G1S 4L8, Canada; (L.-P.G.); (G.L.-B.); (P.D.); (C.C.); (E.G.); (É.B.); (R.B.); (L.G.)
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Québec, QC G1J 1Z4, Canada
- Département d’Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
| | - Gaëtan Le-Bel
- CUO-Recherche, Médecine Régénératrice—Centre de Recherche du CHU de Québec, Université Laval, Québec, QC G1S 4L8, Canada; (L.-P.G.); (G.L.-B.); (P.D.); (C.C.); (E.G.); (É.B.); (R.B.); (L.G.)
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Québec, QC G1J 1Z4, Canada
- Département d’Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
- Département de Chirurgie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
| | - Pascale Desjardins
- CUO-Recherche, Médecine Régénératrice—Centre de Recherche du CHU de Québec, Université Laval, Québec, QC G1S 4L8, Canada; (L.-P.G.); (G.L.-B.); (P.D.); (C.C.); (E.G.); (É.B.); (R.B.); (L.G.)
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Québec, QC G1J 1Z4, Canada
- Département d’Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
- Département de Chirurgie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
| | - Camille Couture
- CUO-Recherche, Médecine Régénératrice—Centre de Recherche du CHU de Québec, Université Laval, Québec, QC G1S 4L8, Canada; (L.-P.G.); (G.L.-B.); (P.D.); (C.C.); (E.G.); (É.B.); (R.B.); (L.G.)
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Québec, QC G1J 1Z4, Canada
- Département d’Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
- Département de Chirurgie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
| | - Elodie Gillard
- CUO-Recherche, Médecine Régénératrice—Centre de Recherche du CHU de Québec, Université Laval, Québec, QC G1S 4L8, Canada; (L.-P.G.); (G.L.-B.); (P.D.); (C.C.); (E.G.); (É.B.); (R.B.); (L.G.)
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Québec, QC G1J 1Z4, Canada
- Département d’Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
| | - Élodie Boisselier
- CUO-Recherche, Médecine Régénératrice—Centre de Recherche du CHU de Québec, Université Laval, Québec, QC G1S 4L8, Canada; (L.-P.G.); (G.L.-B.); (P.D.); (C.C.); (E.G.); (É.B.); (R.B.); (L.G.)
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Québec, QC G1J 1Z4, Canada
- Département d’Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
| | - Richard Bazin
- CUO-Recherche, Médecine Régénératrice—Centre de Recherche du CHU de Québec, Université Laval, Québec, QC G1S 4L8, Canada; (L.-P.G.); (G.L.-B.); (P.D.); (C.C.); (E.G.); (É.B.); (R.B.); (L.G.)
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Québec, QC G1J 1Z4, Canada
- Département d’Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
| | - Lucie Germain
- CUO-Recherche, Médecine Régénératrice—Centre de Recherche du CHU de Québec, Université Laval, Québec, QC G1S 4L8, Canada; (L.-P.G.); (G.L.-B.); (P.D.); (C.C.); (E.G.); (É.B.); (R.B.); (L.G.)
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Québec, QC G1J 1Z4, Canada
- Département d’Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
- Département de Chirurgie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
| | - Sylvain L. Guérin
- CUO-Recherche, Médecine Régénératrice—Centre de Recherche du CHU de Québec, Université Laval, Québec, QC G1S 4L8, Canada; (L.-P.G.); (G.L.-B.); (P.D.); (C.C.); (E.G.); (É.B.); (R.B.); (L.G.)
- Centre de Recherche en Organogénèse Expérimentale de l’Université Laval/LOEX, Québec, QC G1J 1Z4, Canada
- Département d’Ophtalmologie, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada
- Correspondence: ; Tel.: +1-418-682-7565
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Bettahar T, Rahmoune C, Benazzouz D. Keratoconus prognosis study for patients with corneal external mechanical stress mode. Int Ophthalmol 2020; 40:1673-1686. [PMID: 32219616 DOI: 10.1007/s10792-020-01335-2] [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: 09/04/2019] [Accepted: 03/13/2020] [Indexed: 11/28/2022]
Abstract
PURPOSE To demonstrate the correlation between excessive eye rubbing and corneal degeneration for Keratoconus patients. MATERIALS AND METHODS Keratoconus (KC) patients who regularly rub their eyes had shown a rapid degeneration rate of their affected corneas. This observation is experimentally and numerical discussed and developed based on clinical data of 8 of KC Patients with a mean age of 26.5 ± 9.4 years old, and four healthy individuals with a mean age of 24.33 ± 5 years old at the baseline. Corneal topography was used to measure both central corneal thickness (CCT) and its total refractive power. The registered data had been exploited to assess the progression of the disease, and the final results were embedded in a finite element model of human corneas to simulate their response to eye rubbing at different stages of the pathology. Corneal lifetime prognosis using multi-layer perceptron was then established to estimate the number of eye rubbing cycles for each stage of KC. RESULTS The survey of KC patients who declared stopping eye rubbing had shown a decrease in CCT loss rate, followed by a durable stability. Mechanical stresses numerical simulations had shown different corneal behaviours in term of shape deformity, apical raise and corneal applanation between healthy and KC stages models. Apical rise ranged from 0.122 to 0.389 mm for an applied intraocular pressure that equals to 15 mmHg. A normal stress of 5 kPa provoked a corneal applanation that ranged from 0.27 mm in healthy cases to 1.173 mm in severe stages of the disease. The application of 2.5 kPa biaxial stress had resulted normal and tangential applanations that successively ranged from 0.152 and 0.173 mm in healthy corneas to 0.446 mm and 0.458 mm in severe KC stages. An adopted prognosis algorithm was able to predict the current stage of the disease and to estimate the remaining number of eye rubbing cycles before failure. CONCLUSION Eye rubbing was proven to be a considerable contributing factor in KC patient's corneal degeneration. The progression of this pathology could be decreased or halted by stopping eye rubbing at early stages.
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Affiliation(s)
- Toufik Bettahar
- Laboratory of Solid Mechanics and Systems, Mhamed Bougara University, Boumerdes, Algeria.
| | - Chemseddine Rahmoune
- Laboratory of Solid Mechanics and Systems, Mhamed Bougara University, Boumerdes, Algeria
| | - Djamel Benazzouz
- Laboratory of Solid Mechanics and Systems, Mhamed Bougara University, Boumerdes, Algeria
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Da Silva MAO, Gade JT, Damsgaard C, Wang T, Heegaard S, Bertelsen MF. Morphology and evolution of the snake cornea. J Morphol 2019; 281:240-249. [PMID: 31876020 DOI: 10.1002/jmor.21094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 12/06/2019] [Accepted: 12/15/2019] [Indexed: 11/11/2022]
Abstract
To investigate whether the thickness of the cornea in snakes correlates with overall anatomy, habitat or daily activity pattern, we measured corneal thickness using optical coherence tomography scanning in 44 species from 14 families (214 specimens) in the collection at the Natural History Museum (Denmark). Specifically, we analyzed whether the thickness of the cornea varies among species in absolute terms and relative to morphometrics, such as body length, spectacle diameter, and spectacle thickness. Furthermore, we examined whether corneal thickness reflects adaptation to different habitats and/or daily activity patterns. The snakes were defined as arboreal (n = 8), terrestrial (n = 22), fossorial (n = 7), and aquatic (n = 7); 14 species were classified as diurnal and 30 as nocturnal. We reveal that the interspecific variation in corneal thickness is largely explained by differences in body size, but find a tendency towards thicker corneas in diurnal (313 ± 227 μm) compared to nocturnal species (205 ± 169 μm). Furthermore, arboreal snakes had the thickest corneas and fossorial snakes the thinnest. Our study shows that body length, habitat, and daily activity pattern could explain the interspecific variation in corneal morphology among snakes. This study provides a quantitative analysis of the evolution of the corneal morphology in snakes, and it presents baseline values of corneal thickness of multiple snake species. We speculate that the cornea likely plays a role in snake vision, despite the fact that results from previous studies suggest that the cornea in snakes is not relevant for vision (Sivak, Vision Research, 1977, 17, 293-298).
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Affiliation(s)
| | - Jacob Thorup Gade
- Center for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Copenhagen, Denmark
| | - Christian Damsgaard
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Tobias Wang
- Zoophysiology Section, Department of Biosciences, Aarhus University, Aarhus C, Denmark
| | - Steffen Heegaard
- Eye Pathology Section, Department of Pathology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Ophthalmology, Rigshospitalet, University of Copenhagen, Glostrup, Denmark
| | - Mads Frost Bertelsen
- Center for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Copenhagen, Denmark
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Jindal R, Sinha R. Malachite Green Induced Ultrastructural Corneal Lesions in Cyprinus carpio and Its Amelioration Using Emblica officinalis. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2019; 102:377-384. [PMID: 30673810 DOI: 10.1007/s00128-019-02549-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 01/12/2019] [Indexed: 06/09/2023]
Abstract
Malachite green, a multi-purpose dye induces cyto-toxicity upon its entry and bioaccumulation in tissues. A semi-static chronic (60 days) bioassay was conducted by exposing Cyprinus carpio to sublethal concentration of the dye and Emblica officinalis in four experimental groups viz control, malachite green, E. officinalis, and malachite green + E. officinalis. Effect of dye on the cornea was investigated considering ultra-structural alterations owing to its direct contact to the pollutant in the aquatic medium. SEM studies on corneal epithelium revealed broken continuity of pavement cells, shrunk microplicae, increased intra-microplicae distance, globularization and epithelial uplifting, thereby affecting the integrity of corneal surface and tear film adherence. Whereas dietary supplementation with the plant extract served to restore cytoarchitecture with appearance of large number of regenerating cells. Both lesions and restoration were found to be duration dependent. Thus, E. officinalis can be considered as an effective ameliorant against malachite green induced toxicity.
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Affiliation(s)
- Rajinder Jindal
- Department of Zoology, Panjab University, 160 014, Chandigarh, India.
| | - Reshma Sinha
- Department of Zoology, Panjab University, 160 014, Chandigarh, India
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Matthyssen S, Van den Bogerd B, Dhubhghaill SN, Koppen C, Zakaria N. Corneal regeneration: A review of stromal replacements. Acta Biomater 2018; 69:31-41. [PMID: 29374600 DOI: 10.1016/j.actbio.2018.01.023] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/16/2018] [Accepted: 01/16/2018] [Indexed: 12/13/2022]
Abstract
Corneal blindness is traditionally treated by transplantation of a donor cornea, or in severe cases by implantation of an artificial cornea or keratoprosthesis. Due to severe donor shortages and the risks of complications that come with artificial corneas, tissue engineering in ophthalmology has become more focused on regenerative strategies using biocompatible materials either with or without cells. The stroma makes up the bulk of the corneal thickness and mainly consists of a tightly interwoven network of collagen type I, making it notoriously difficult to recreate in a laboratory setting. Despite the challenges that come with corneal stromal tissue engineering, there has recently been enormous progress in this field. A large number of research groups are working towards developing the ideal biomimetic, cytocompatible and transplantable stromal replacement. Here we provide an overview of the approaches directed towards tissue engineering the corneal stroma, from classical collagen gels, films and sponges to less traditional components such as silk, fish scales, gelatin and polymers. The perfect stromal replacement has yet to be identified and future research should be directed at combined approaches, in order to not only host native stromal cells but also restore functionality. STATEMENT OF SIGNIFICANCE In the field of tissue engineering and regenerative medicine in ophthalmology the focus has shifted towards a common goal: to restore the corneal stroma and thereby provide a new treatment option for patients who are currently blind due to corneal opacification. Currently the waiting lists for corneal transplantation include more than 10 million patients, due to severe donor shortages. Alternatives to the transplantation of a donor cornea include the use of artificial cornea, but these are by no means biomimetic and therefore do not provide good outcomes. In recent years a lot of work has gone into the development of tissue engineered scaffolds and other biomaterials suitable to replace the native stromal tissue. Looking at all the different approaches separately is a daunting task and up until now there was no review article in which every approach is discussed. This review does include all approaches, from classical tissue engineering with collagen to the use of various alternative biomaterials and even fish scales. Therefore, this review can serve as a reference work for those starting in the field and but also to stimulate collaborative efforts in the future.
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Asena L, Alkayid H, Altınörs DD. Corneal Epithelial Wound Healing and Management Strategies. PLASTIC AND THORACIC SURGERY, ORTHOPEDICS AND OPHTHALMOLOGY 2018. [DOI: 10.1007/15695_2017_65] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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McKay TB, Karamichos D. Quercetin and the ocular surface: What we know and where we are going. Exp Biol Med (Maywood) 2017; 242:565-572. [PMID: 28056553 PMCID: PMC5685256 DOI: 10.1177/1535370216685187] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Flavonoids are a class of plant and fungus secondary metabolites that serve functional roles in protecting against UV-induced oxidative stress, mediating auxin signaling, and promoting microbial defense. Flavonoids are extremely abundant in nature where their potent antioxidant capacity and very low toxicity makes them highly attractive as potential therapeutic agents. In terms of clinical applications, neither the Food and Drug Administration (FDA) nor the European Food Safety Authority (EFSA) has approved any health claims or drugs related to the use of flavonoids for therapeutic purposes. Quercetin is a common flavonol that has been shown to have potent antioxidant, anti-inflammatory, and anti-fibrotic activities both in vitro and in vivo in various tissues. Recently, the application of quercetin as a therapeutic has been gaining attention in the ocular surface scientific community in the study of dry eye, keratoconus, inflammation, and neovascularization of the cornea. This review will discuss the latest findings and the use of quercetin for the treatment of dystrophies of the ocular surface. Impact statement The eye represents a small portion of the human body, accounting for one decimal fraction of the anterior body surface. The cornea is an avascular, transparent tissue that acts as a primary barrier against mechanical and infectious damaging agents, protecting the internal structures of the eye. Corneal survival and function are affected by a number of factors including but not limited to injury, trauma, infection, genetics, and environment. Corneal injury, or trauma, often leads to loss of corneal transparency and even blindness. The concept of "curing" corneal opacity has been discussed in published form for over 200 years. Currently, full corneal transplant is the only treatment option. There is a strong interest in developing natural therapeutic products that come with minimum side effects. A novel antioxidant flavonoid, quercetin, has been gaining traction as a potential therapeutic to prevent the injured cornea. This review discusses the potential of this antioxidant.
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Affiliation(s)
- Tina B McKay
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104,USA
| | - Dimitrios Karamichos
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104,USA
- Department of Ophthalmology, Dean McGee Eye Institute, Oklahoma City, OK 73104, USA
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Hu W, Zhang J, Kang B. Structure and function of corneal surface of mudskipper fishes. FISH PHYSIOLOGY AND BIOCHEMISTRY 2016; 42:1481-1489. [PMID: 27178187 DOI: 10.1007/s10695-016-0234-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 05/02/2016] [Indexed: 06/05/2023]
Abstract
Vertebrate corneal epithelium cell plays an important role for imaging, and the cell density, together with the appearance or type of affiliated microstructures, is considered as a result of evolution adapting to alternate terrestrial or aquatic environment. In this paper, we investigated the corneal cells of both larvae and adult amphibious mudskippers Boleophthalmus pectinirostris and Periophthalmus magnuspinnatus, to testify the relationship between morphology and function. The cell density values of the two species were 31,137 and 31,974 cells per mm(2) in larvae and then significantly decreased to 15,826 and 25,954 cells per mm(2) in adult (p < 0.001), respectively, which could be explained as the habitat change from aquatic to different degrees of terrestrial environment. The corneal epithelium cells were ridge type in larvae and differentiated into ridge type and reticular type in adult P. magnuspinnatus and ridge type, reticular type and ridge-reticular type in adult B. pectinirostris. Four kinds of microstructures as microridge, microvilli, microplicae and microhole appeared in both species. The difference of microridge width and its separation indicated that a dense cell connection was requested in a saltier and more terrestrial environment.
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Affiliation(s)
- Wenxian Hu
- School of Life Sciences, Yunnan University, Kunming, People's Republic of China
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jie Zhang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Bin Kang
- School of Life Sciences, Yunnan University, Kunming, People's Republic of China.
- Fishery College, Jimei University, Xiamen, 361021, China.
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Shan M, Fan TJ. Cytotoxicity of carteolol to human corneal epithelial cells by inducing apoptosis via triggering the Bcl-2 family protein-mediated mitochondrial pro-apoptotic pathway. Toxicol In Vitro 2016; 35:36-42. [DOI: 10.1016/j.tiv.2016.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/09/2016] [Accepted: 05/19/2016] [Indexed: 01/09/2023]
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Benoit A, Latour G, Marie-Claire SK, Allain JM. Simultaneous microstructural and mechanical characterization of human corneas at increasing pressure. J Mech Behav Biomed Mater 2015; 60:93-105. [PMID: 26773650 DOI: 10.1016/j.jmbbm.2015.12.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 09/23/2015] [Accepted: 12/22/2015] [Indexed: 11/24/2022]
Abstract
The cornea, through its shape, is the main contributor to the eye׳s focusing power. Pathological alterations of the cornea strongly affect the eye power. To improve treatments, complex biomechanical models have been developed based on the architecture and mechanical properties of the collagen network in the stroma, the main layer of the cornea. However, direct investigations of the structure of the stroma, as well as its link to the mechanical response, remained limited. We propose here an original set up, associating nonlinear optical imaging and mechanical testing. By using polarization resolved Second Harmonic signals, we simultaneously quantified micrometer (orientation of the collagen lamellae) and nanometer (local disorder within lamellae) scale corneal organization. We showed that the organization of the lamellae changes along the stroma thickness. Then, we measured simultaneously the deformation on the epithelial side of the cornea and the reorientation of the collagen lamellae for increasing intraocular pressure levels, from physiological ones to pathological ones. We showed that the observed deformation is not correlated to initial orientation, but to the reorganization of the lamellae in the stroma. Our results, by providing a direct multi-scale observation, will be useful for the development of more accurate biomechanical models.
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Affiliation(s)
- Aurélie Benoit
- LMS, École polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau, France
| | - Gaël Latour
- LOB, École polytechnique, CNRS, Inserm U1128, Université Paris-Saclay, 91128 Palaiseau cedex, France; IMNC, Univ. Paris-Sud, Univ. Paris-Diderot, CNRS, Université Paris-Saclay, 91405 Orsay cedex, France
| | | | - Jean-Marc Allain
- LMS, École polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau, France.
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Saraswathi P, Beuerman RW. Corneal Biofilms: From Planktonic to Microcolony Formation in an Experimental Keratitis Infection with Pseudomonas Aeruginosa. Ocul Surf 2015. [DOI: 10.1016/j.jtos.2015.07.001 [pii]] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Sehic A, Utheim ØA, Ommundsen K, Utheim TP. Pre-Clinical Cell-Based Therapy for Limbal Stem Cell Deficiency. J Funct Biomater 2015; 6:863-88. [PMID: 26343740 PMCID: PMC4598682 DOI: 10.3390/jfb6030863] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 08/10/2015] [Accepted: 08/21/2015] [Indexed: 12/13/2022] Open
Abstract
The cornea is essential for normal vision by maintaining transparency for light transmission. Limbal stem cells, which reside in the corneal periphery, contribute to the homeostasis of the corneal epithelium. Any damage or disease affecting the function of these cells may result in limbal stem cell deficiency (LSCD). The condition may result in both severe pain and blindness. Transplantation of ex vivo cultured cells onto the cornea is most often an effective therapeutic strategy for LSCD. The use of ex vivo cultured limbal epithelial cells (LEC), oral mucosal epithelial cells, and conjunctival epithelial cells to treat LSCD has been explored in humans. The present review focuses on the current state of knowledge of the many other cell-based therapies of LSCD that have so far exclusively been explored in animal models as there is currently no consensus on the best cell type for treating LSCD. Major findings of all these studies with special emphasis on substrates for culture and transplantation are systematically presented and discussed. Among the many potential cell types that still have not been used clinically, we conclude that two easily accessible autologous sources, epidermal stem cells and hair follicle-derived stem cells, are particularly strong candidates for future clinical trials.
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Affiliation(s)
- Amer Sehic
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Sognsvannsveien 10, Oslo 0372, Norway.
| | - Øygunn Aass Utheim
- Department of Ophthalmology, Oslo University Hospital, Kirkeveien 166, Oslo 0407, Norway.
| | - Kristoffer Ommundsen
- Department of Medical Biochemistry, Oslo University Hospital, Kirkeveien 166, Oslo 0407, Norway.
| | - Tor Paaske Utheim
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, Sognsvannsveien 10, Oslo 0372, Norway.
- Department of Medical Biochemistry, Oslo University Hospital, Kirkeveien 166, Oslo 0407, Norway.
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Saraswathi P, Beuerman RW. Corneal Biofilms: From Planktonic to Microcolony Formation in an Experimental Keratitis Infection with Pseudomonas Aeruginosa. Ocul Surf 2015. [PMID: 26220579 DOI: 10.1016/j.jtos.2015.07.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE Microbial biofilms commonly comprise part of the infectious scenario, complicating the therapeutic approach. The purpose of this study was to determine in a mouse model of corneal infection if mature biofilms formed and to visualize the stages of biofilm formation. METHODS A bacterial keratitis model was established using Pseudomonas aeruginosa ATCC 9027 (1 × 10(8) CFU/ml) to infect the cornea of C57BL/6 black mouse. Eyes were examined post-infection (PI) on days 1, 2, 3, 5, and 7, and imaged by slit lamp microscopy, and light, confocal, and electron microscopy to identify the stages of biofilm formation and the time of appearance. RESULTS On PI day 1, Gram staining showed rod-shaped bacteria adherent on the corneal surface. On PI days 2 and 3, bacteria were seen within webs of extracellular polymeric substance (EPS) and glycocalyx secretion, imaged by confocal microscopy. Scanning electron microscopy demonstrated microcolonies of active infectious cells bound with thick fibrous material. Transmission electron microscopy substantiated the formation of classical biofilm architecture with P. aeruginosa densely packed within the extracellular polymeric substances on PI days 5 and 7. CONCLUSION Direct visual evidence showed that biofilms routinely developed on the biotic surface of the mouse cornea. The mouse model can be used to develop new approaches to deal therapeutically with biofilms in corneal infections.
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Affiliation(s)
| | - Roger W Beuerman
- Singapore Eye Research Institute (SERI), Singapore; Duke-NUS SRP Neuroscience and Behavioural Disorders and Emerging Infectious Diseases, Singapore; Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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Ultrastructure Organization of Collagen Fibrils and Proteoglycans of Stingray and Shark Corneal Stroma. J Ophthalmol 2015; 2015:686914. [PMID: 26167294 PMCID: PMC4488252 DOI: 10.1155/2015/686914] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Revised: 05/24/2015] [Accepted: 06/02/2015] [Indexed: 12/02/2022] Open
Abstract
We report here the ultrastructural organization of collagen fibrils (CF) and proteoglycans (PGs) of the corneal stroma of both the stingray and the shark. Three corneas from three stingrays and three corneas from three sharks were processed for electron microscopy. Tissues were embedded in TAAB 031 resin. The corneal stroma of both the stingray and shark consisted of parallel running lamellae of CFs which were decorated with PGs. In the stingray, the mean area of PGs in the posterior stroma was significantly larger than the PGs of the anterior and middle stroma, whereas, in the shark, the mean area of PGs was similar throughout the stroma. The mean area of PGs of the stingray was significantly larger compared to the PGs, mean area of the shark corneal stroma. The CF diameter of the stingray was significantly smaller compared to the CF diameter in the shark. The ultrastructural features of the corneal stroma of both the stingray and the shark were similar to each other except for the CFs and PGs. The PGs in the stingray and shark might be composed of chondroitin sulfate (CS)/dermatan sulfate (DS) PGs and these PGs with sutures might contribute to the nonswelling properties of the cornea of the stingray and shark.
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Ţălu Ş, Stach S, Sueiras V, Ziebarth NM. Fractal analysis of AFM images of the surface of Bowman's membrane of the human cornea. Ann Biomed Eng 2015; 43:906-16. [PMID: 25266935 DOI: 10.1007/s10439-014-1140-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 09/23/2014] [Indexed: 02/07/2023]
Abstract
The objective of this study is to further investigate the ultrastructural details of the surface of Bowman's membrane of the human cornea, using atomic force microscopy (AFM) images. One representative image acquired of Bowman's membrane of a human cornea was investigated. The three-dimensional (3-D) surface of the sample was imaged using AFM in contact mode, while the sample was completely submerged in optisol solution. Height and deflection images were acquired at multiple scan lengths using the MFP-3D AFM system software (Asylum Research, Santa Barbara, CA), based in IGOR Pro (WaveMetrics, Lake Oswego, OR). A novel approach, based on computational algorithms for fractal analysis of surfaces applied for AFM data, was utilized to analyze the surface structure. The surfaces revealed a fractal structure at the nanometer scale. The fractal dimension, D, provided quantitative values that characterize the scale properties of surface geometry. Detailed characterization of the surface topography was obtained using statistical parameters, in accordance with ISO 25178-2: 2012. Results obtained by fractal analysis confirm the relationship between the value of the fractal dimension and the statistical surface roughness parameters. The surface structure of Bowman's membrane of the human cornea is complex. The analyzed AFM images confirm a fractal nature of the surface, which is not taken into account by classical surface statistical parameters. Surface fractal dimension could be useful in ophthalmology to quantify corneal architectural changes associated with different disease states to further our understanding of disease evolution.
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Affiliation(s)
- Ştefan Ţălu
- Discipline of Descriptive Geometry and Engineering Graphics, Department of AET, Faculty of Mechanical Engineering, Technical University of Cluj-Napoca, 103-105 B-dul Muncii St., 400641, Cluj-Napoca, Cluj, Romania,
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Levendoski EE, Leydon C, Thibeault SL. Vocal fold epithelial barrier in health and injury: a research review. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2014; 57:1679-91. [PMID: 24686981 PMCID: PMC4557797 DOI: 10.1044/2014_jslhr-s-13-0283] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 03/04/2014] [Indexed: 05/07/2023]
Abstract
PURPOSE Vocal fold epithelium is composed of layers of individual epithelial cells joined by junctional complexes constituting a unique interface with the external environment. This barrier provides structural stability to the vocal folds and protects underlying connective tissue from injury while being nearly continuously exposed to potentially hazardous insults, including environmental or systemic-based irritants such as pollutants and reflux, surgical procedures, and vibratory trauma. Small disruptions in the epithelial barrier may have a large impact on susceptibility to injury and overall vocal health. The purpose of this article is to provide a broad-based review of current knowledge of the vocal fold epithelial barrier. METHOD A comprehensive review of the literature was conducted. Details of the structure of the vocal fold epithelial barrier are presented and evaluated in the context of function in injury and pathology. The importance of the epithelial-associated vocal fold mucus barrier is also introduced. RESULTS/CONCLUSIONS Information presented in this review is valuable for clinicians and researchers as it highlights the importance of this understudied portion of the vocal folds to overall vocal health and disease. Prevention and treatment of injury to the epithelial barrier is a significant area awaiting further investigation.
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D'hondt C, Iyyathurai J, Himpens B, Leybaert L, Bultynck G. Cx43-hemichannel function and regulation in physiology and pathophysiology: insights from the bovine corneal endothelial cell system and beyond. Front Physiol 2014; 5:348. [PMID: 25309448 PMCID: PMC4162354 DOI: 10.3389/fphys.2014.00348] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 08/25/2014] [Indexed: 12/13/2022] Open
Abstract
Intercellular communication in primary bovine corneal endothelial cells (BCECs) is mainly driven by the release of extracellular ATP through Cx43 hemichannels. Studying the characteristics of Ca2+-wave propagation in BCECs, an important form of intercellular communication, in response to physiological signaling events has led to the discovery of important insights in the functional properties and regulation of native Cx43 hemichannels. Together with ectopic expression models for Cx43 hemichannels and truncated/mutated Cx43 versions, it became very clear that loop/tail interactions play a key role in controlling the activity of Cx43 hemichannels. Interestingly, the negative regulation of Cx43 hemichannels by enhanced actin/myosin contractility seems to impinge upon loss of these loop/tail interactions essential for opening Cx43 hemichannels. Finally, these molecular insights have spurred the development of novel peptide tools that can selectively inhibit Cx43 hemichannels, but neither Cx43 gap junctions nor hemichannels formed by other Cx isoforms. These tools now set the stage to hunt for novel physiological functions for Cx43 hemichannels in primary cells and tissues and to tackle disease conditions associated with excessive, pathological Cx43-hemichannel openings.
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Affiliation(s)
- Catheleyne D'hondt
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven Leuven, Belgium
| | - Jegan Iyyathurai
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven Leuven, Belgium
| | - Bernard Himpens
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven Leuven, Belgium
| | - Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University Ghent, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven Leuven, Belgium
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Lajunen T, Hisazumi K, Kanazawa T, Okada H, Seta Y, Yliperttula M, Urtti A, Takashima Y. Topical drug delivery to retinal pigment epithelium with microfluidizer produced small liposomes. Eur J Pharm Sci 2014; 62:23-32. [PMID: 24810393 DOI: 10.1016/j.ejps.2014.04.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/24/2014] [Accepted: 04/26/2014] [Indexed: 10/25/2022]
Abstract
Drug delivery from topically instilled eye drops to the posterior segment of the eye has long been one of the greatest challenges of ocular drug development. We developed methods of liposome preparation utilizing a microfluidizer to achieve adjustable nanoparticle size (even less than 80 nm) and high loading capacity of plasmid DNA. The microfluidizing process parameters were shown to affect the size of the liposomes. Higher operating pressures and passage for at least 10 times through the microfluidizer produced small liposomes with narrow size distribution. The liposomes were physically stable for several months at +4°C. In vivo distribution of the optimized liposome formulations in the rat eyes was investigated with confocal microscopy of the histological specimens. Transferrin was used as a targeting ligand directed to retinal pigment epithelium. Size dependent distribution of liposomes to different posterior segment tissues was seen. Liposomes with the diameter less than 80 nm permeated to the retinal pigment epithelium whereas liposomes with the diameter of 100 nm or more were distributed to the choroidal endothelium. Active targeting was shown to be necessary for liposome retention to the target tissue. In conclusion, these microfluidizer produced small liposomes in eye drops are an attractive option for drug delivery to the posterior segment tissues of the eye.
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Affiliation(s)
- T Lajunen
- Tokyo University of Pharmacy & Life Sciences, Japan; Centre for Drug Research, Division of Pharmaceutical Biosciences, University of Helsinki, Finland
| | | | - T Kanazawa
- Tokyo University of Pharmacy & Life Sciences, Japan
| | - H Okada
- Tokyo University of Pharmacy & Life Sciences, Japan
| | - Y Seta
- Tokyo University of Pharmacy & Life Sciences, Japan
| | - M Yliperttula
- Centre for Drug Research, Division of Pharmaceutical Biosciences, University of Helsinki, Finland
| | - A Urtti
- Centre for Drug Research, Division of Pharmaceutical Biosciences, University of Helsinki, Finland; School of Pharmacy, University of Eastern Finland, Finland
| | - Y Takashima
- Tokyo University of Pharmacy & Life Sciences, Japan.
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Re: Jester et al.: Lessons in Corneal Structure and Mechanics to Guide the Corneal Surgeon (Ophthalmology 2013;120:1715-1717). Ophthalmology 2014; 121:e18. [DOI: 10.1016/j.ophtha.2013.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 12/02/2013] [Indexed: 11/19/2022] Open
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Kilic C, Girotti A, Rodriguez-Cabello JC, Hasirci V. A collagen-based corneal stroma substitute with micro-designed architecture. Biomater Sci 2014; 2:318-29. [DOI: 10.1039/c3bm60194c] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Characteristic quantities of corneal epithelial structures in confocal laser scanning microscopic volume data sets. Cornea 2013; 32:636-43. [PMID: 23132439 DOI: 10.1097/ico.0b013e31826247bf] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Fully automated quantification of the morphologic features of different epithelial cell layers in healthy human corneas. METHODS In vivo confocal laser scanning microscopy was performed on the unilateral eyes of 6 healthy volunteers. Stacks of 160 images (400 × 400 μm) with an interslice distance of 0.4 μm were used to generate full thickness volume data sets of the epithelium. Size and shape factors of basal (BC) and intermediate cell (IC) layers were quantified using appropriate image analysis algorithms. Evaluated parameters include mean area, compactness, solidity, major and minor diameter, and maximum boundary distance. RESULTS Mean area of BC and IC demonstrated a linear increase from 80 to 160 μm². A similar trend was noted with major and minor diameter and maximum boundary distance. Major diameters of BC and IC measured between 13.2 and 17.0 μm, whereas minor diameter of these cells measured between 8.6 and 12.4 μm. The maximum boundary distance of BC and IC ranged from 7.0 to 9.1 μm. Compactness of epithelial cells clustered around 1.45 and 1.5, whereas cell solidity measured between 1.0 and 1.03. CONCLUSION Several characteristic morphologic quantities can be calculated using this methodology without manual intervention. Our study demonstrated promising results and suggests that this fully automated morphologic quantification can be successfully applied to assess microstructural changes of the epithelium in normal and various corneal disorders.
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Corneal Sublayers Thickness Estimation Obtained by High-Resolution FD-OCT. Int J Biomed Imaging 2013; 2013:989624. [PMID: 23818895 PMCID: PMC3684120 DOI: 10.1155/2013/989624] [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: 03/05/2013] [Accepted: 05/21/2013] [Indexed: 11/17/2022] Open
Abstract
This paper presents a novel processing technique which can be applied to corneal in vivo images obtained with optical coherence tomograms across the central meridian of the cornea. The method allows to estimate the thickness of the corneal sublayers (Epithelium, Bowman's layer, Stroma, Endothelium, and whole corneal thickness) at any location, including the center and the midperiphery, on both nasal and temporal sides. The analysis is carried out on both the pixel and subpixel scales to reduce the uncertainty in thickness estimations. This technique allows quick and noninvasive assessment of patients. As an example of application and validation, we present the results obtained from the analysis of 52 healthy subjects, each with 3 scans per eye, for a total of more than 300 images. Particular attention has been paid to the statistical interpretation of the obtained results to find a representative assessment of each sublayer's thickness.
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Zhang Y, Mao X, Schwend T, Littlechild S, Conrad GW. Resistance of corneal RFUVA–cross-linked collagens and small leucine-rich proteoglycans to degradation by matrix metalloproteinases. Invest Ophthalmol Vis Sci 2013; 54:1014-25. [PMID: 23322569 DOI: 10.1167/iovs.12-11277] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Extracellular matrix metalloproteinases (MMPs) are thought to play a crucial role in corneal degradation associated with the pathological progression of keratoconus. Currently, corneal cross-linking by riboflavin and ultraviolet A (RFUVA) has received significant attention for treatment of keratoconus. However, the extent to which MMPs digest cross-linked collagen and small leucine-rich proteoglycans (SLRPs) remains unknown. In this study, the resistance of RFUVA-cross-linked collagens and SLRPs to MMPs has been investigated. METHODS To investigate the ability of MMPs to digest cross-linked collagen and SLRPs, a model reaction system using purified collagen type I, type IV, and nonglycosylated, commercially available recombinant SLRPs, keratocan, lumican, mimecan, decorin, and biglycan in solution in vitro has been compared using reactions inside an intact bovine cornea, ex vivo. RESULTS Our data demonstrate that corneal cross-linked collagen type I and type IV are resistant to cleavage by MMP-1, MMP-2, MMP-9, and MMP-13, whereas non-cross-linked collagen I, IV, and natively glycosylated SLRPs are susceptible to degradation by MMPs. In addition, both cross-linked SLRPs themselves and cross-linked polymers of SLRPs and collagen appear able to resist degradation. These results suggest that the interactions between SLRPs and collagen caused by RFUVA protect both SLRPs and collagen fibrils from cleavage by MMPs. CONCLUSIONS A novel approach for understanding the biochemical mechanism whereby RFUVA cross-linking stops keratoconus progression has been achieved.
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Affiliation(s)
- Yuntao Zhang
- Division of Biology, Kansas State University, Manhattan, Kansas 66506-4901, USA.
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Zhu HY, Yeo SW, Ng J, Htoon HM, Beuerman RW. Moesin as a key cytoskeleton regulator in corneal fibrosis. Ocul Surf 2013; 11:119-32. [PMID: 23583046 DOI: 10.1016/j.jtos.2013.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 07/18/2012] [Accepted: 12/01/2012] [Indexed: 11/30/2022]
Abstract
PURPOSE : Corneal fibrosis is the third leading cause of blindness worldwide. α-Smooth muscle actin (SMA), a marker of fibrosis, is closely regulated through an intermediate group of submembrane molecules - cytoskeleton regulators. The purpose of this study was to elucidate the role of specific cytoskeleton regulators in a mouse model of corneal fibrosis. METHODS : A mouse model of corneal fibrosis was developed using anterior keratectomy (AK) and the topical application of transforming growth factor (TGF)-β1 (1 μg/ml). The RT² Profiler™ PCR Array for cytoskeleton regulators was used to assay changes in levels of specific members of this class of proteins. Moesin siRNA was delivered into the corneal stroma by iontophoresis in vivo. Transformation of the corneal keratocyte-to-myofibroblast in corneal fibrosis, as defined by the expression of α-SMA, was determined by Western blot. RESULTS : After AK and topical application of TGF-β1, moesin was the most highly upregulated gene among 84 cytoskeleton regulator genes; iontophoresing moesin siRNA into the corneal stroma reduced the expression of α-SMA to 0.22-, 0.52-, and 0.31-fold of control at postoperative (PO) day 1, 3, and 5, respectively; also, upregulation of phospho-Smad 2 induced by TGF-β1 was reduced by moesin siRNA to 0.59-, 0.56-, and 0.31-fold of control and expression of phospho-Smad 3 was reduced to 0.58-, 0.53-, and 0.47-fold of control at the same PO days. CONCLUSIONS : Moesin may be a potential drug target for inhibiting corneal fibrosis, and the details of moesin-related signaling pathways would be critical for understanding corneal fibrosis.
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Abstract
The cornea, the clear window at the front of the eye, transmits light to the retina to enable vision. The corneal surface is renewed by stem cells located at the peripheral limbal region. These cells can be destroyed by a number of factors, including chemical burns, infections, and autoimmune diseases, which result in limbal stem cell deficiency (LSCD), a condition that can lead to blindness. Established therapy for LSCD based on ex vivo expanded limbal epithelial cells is currently at a stage of refinement. Therapy for LSCD is also rapidly evolving to include alternative cell types and clinical approaches as treatment modalities. In the present perspectives chapter, strategies to treat LSCD are discussed and advances in this important field of regenerative medicine are highlighted.
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Affiliation(s)
- Tor Paaske Utheim
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
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Fannon M, Forsten-Williams K, Zhao B, Bach E, Parekh PP, Chu CL, Goerges-Wildt AL, Buczek-Thomas JA, Nugent MA. Facilitated diffusion of VEGF165 through descemet's membrane with sucrose octasulfate. J Cell Physiol 2012; 227:3693-700. [PMID: 22378222 DOI: 10.1002/jcp.24077] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Vascular endothelial growth factor A (VEGF-A) is a promoter of neovascularization and thus a popular therapeutic target for diseases involving excessive growth of blood vessels. In this study, we explored the potential of the disaccharide sucrose octasulfate (SOS) to alter VEGF165 diffusion through Descemet's membrane. Descemet's membranes were isolated from bovine eyes and used as a barrier between two chambers of a diffusion apparatus to measure VEGF transport. Diffusion studies revealed a dramatic increase in VEGF165 transport in the presence of SOS, with little diffusion of VEGF165 across the membrane over a 10-h time course in the absence of SOS. Diffusion studies with VEGF121, a non-heparin binding variant of VEGF, showed robust diffusion with or without SOS. To determine a possible mechanism, we measured the ability of SOS to inhibit VEGF interactions with extracellular matrix (ECM), using cell-free and cell surface binding assays. Binding studies showed SOS had no effect on VEGF165 binding to either heparin-coated plates or endothelial cell surfaces at less than mg/ml concentrations. In contrast, we show that SOS inhibited VEGF165 binding to fibronectin in a dose dependent manner and dramatically accelerated the rate of release of VEGF165 from fibronectin. SOS also inhibited the binding of VEGF165 to fibronectin-rich ECM deposited by vascular smooth muscle cells. These results suggest that fibronectin-rich extracellular matrices serve as barriers to VEGF165 diffusion by providing a network of binding sites that can trap and sequester the protein. Since the content of Descemet's membrane is typical of many basement membranes it is possible that they serve throughout the body as formidable barriers to VEGF165 diffusion and tightly regulate its bioavailability and distribution within tissues.
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Affiliation(s)
- Michael Fannon
- Department of Ophthalmology and Visual Sciences, University of Kentucky, Lexington, KY 40536-0305, USA.
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Tavakoli M, Petropoulos IN, Malik RA. Assessing corneal nerve structure and function in diabetic neuropathy. Clin Exp Optom 2012; 95:338-47. [PMID: 22594548 DOI: 10.1111/j.1444-0938.2012.00743.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The accurate detection and quantification of human diabetic peripheral neuropathy are important to define at-risk patients, anticipate deterioration and assess new therapies. Two emerging ophthalmic techniques, namely, corneal confocal microscopy and corneal aesthesiometry, demonstrate the ability to diagnose, quantify severity and assess therapeutic benefit in diabetic peripheral neuropathy. Corneal confocal microscopy allows quantification of corneal nerve morphology and non-contact corneal aesthesiometry assesses corneal sensitivity. The present review provides a detailed critique of the rationale, practical application in terms of the instruments used to capture images and the basis on which images are interpreted and analysed. We also critically evaluate how these two new non-invasive ophthalmic tests can be deployed to diagnose diabetic and other peripheral neuropathies.
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Affiliation(s)
- Mitra Tavakoli
- Division of Cardiovascular Medicine, University of Manchester, Manchester, United Kingdom.
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The defence architecture of the superficial cells of the oral mucosa. Med Hypotheses 2012; 78:790-2. [DOI: 10.1016/j.mehy.2012.03.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 03/07/2012] [Indexed: 12/18/2022]
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Prakasam RK, Schwiede M, Hütz WW, Guthoff RF, Stachs O. Corneal Responses to Eye Rubbing with Spectral Domain Optical Coherence Tomography. Curr Eye Res 2011; 37:25-32. [DOI: 10.3109/02713683.2011.622850] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Laaser K, Bachmann BO, Horn FK, Schlötzer-Schrehardt U, Cursiefen C, Kruse FE. Donor tissue culture conditions and outcome after descemet membrane endothelial keratoplasty. Am J Ophthalmol 2011; 151:1007-1018.e2. [PMID: 21334592 DOI: 10.1016/j.ajo.2010.11.027] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2010] [Revised: 11/22/2010] [Accepted: 11/22/2010] [Indexed: 10/18/2022]
Abstract
PURPOSE To investigate the effect of culture conditions of donor tissue on functional outcome after Descemet membrane endothelial keratoplasty. DESIGN Retrospective, single-center, consecutive case series. METHODS Descemet membrane endothelial keratoplasty was performed routinely in 82 eyes of 82 consecutive patients using corneal donor tissue prestored in either short-term culture (Optisol-GS; Bausch & Lomb) at 4 C (group A; n = 37) or organ culture (Dulbecco Modified Eagle Medium [Biochrom]; CorneaMax Medium [Eurobio]) at 34 C (group B; n = 45) in a randomized fashion. Main outcome measures included the number of air injections necessary for graft attachment as well as best-corrected visual acuity (in logarithm of the minimal angle of resolution [logMAR] units), central corneal thickness, and endothelial cell density at 1, 3, and 6 months after surgery. RESULTS Best-corrected visual acuity increased from 0.69 ± 0.53 logMAR and 0.67 ± 0.31 logMAR before surgery to 0.33 ± 0.21 logMAR and 0.28 ± 0.18 logMAR after 1 month (P < .05), to 0.24 ± 0.16 logMAR and 0.18 ± 0.16 logMAR after 3 months (P < .05), and to 0.18 ± 0.12 logMAR and 0.15 ± 0.10 logMAR after 6 months (n.s.) in groups A and B, respectively. Endothelial cell density decreased from 2647 ± 236 cells/mm(2) and 2515 ± 249 cells/mm(2) before surgery to 1499 ± 277 cells/mm(2) and 1526 ± 205 cells/mm(2) after 1 month (P < .05), to 1441 ± 213 cells/mm(2) and 1443 ± 316 cells/mm(2) after 3 months (n.s.), and to 1587 ± 366 cells/mm(2) and 1457 ± 285 cells/mm(2) after 6 months (n.s.) in groups A and B, respectively. Central corneal thickness declined from 664 ± 89 and 662 ± 107 μm before surgery to 529 ± 92 μm and 517 ± 62 μm after 1 month (P < .05), to 511 ± 46 μm and 510 ± 46 μm after 3 months (P < .05), and to 529 ± 68 μm and 507 ± 50 μm after 6 months (n.s.) in groups A and B, respectively. Best-corrected visual acuity, endothelial cell density, and central corneal thickness values showed no significant differences between both groups at any time point after surgery. However, a significantly higher total number of air injections was necessary in group A (n = 34) compared with group B (n = 26) to obtain graft attachment (P < .05). CONCLUSIONS These findings suggest that donor tissue culture conditions have no significant effect on functional outcome, but may influence graft adhesion and rebubbling rate after Descemet membrane endothelial keratoplasty surgery.
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Detzel CJ, Larkin AL, Rajagopalan P. Polyelectrolyte multilayers in tissue engineering. TISSUE ENGINEERING. PART B, REVIEWS 2011; 17:101-13. [PMID: 21210759 PMCID: PMC3062467 DOI: 10.1089/ten.teb.2010.0548] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 01/03/2011] [Indexed: 11/13/2022]
Abstract
The layer-by-layer assembly of sequentially adsorbed, alternating polyelectrolytes has become increasingly important over the past two decades. The ease and versatility in assembling polyelectrolyte multilayers (PEMs) has resulted in numerous wide ranging applications of these materials. More recently, PEMs are being used in biological applications ranging from biomaterials, tissue engineering, regenerative medicine, and drug delivery. The ability to manipulate the chemical, physical, surface, and topographical properties of these multilayer architectures by simply changing the pH, ionic strength, thickness, and postassembly modifications render them highly suitable to probe the effects of external stimuli on cellular responsiveness. In the field of regenerative medicine, the ability to sequester growth factors and to tether peptides to PEMs has been exploited to direct the lineage of progenitor cells and to subsequently maintain a desired phenotype. Additional novel applications include the use of PEMs in the assembly of three-dimensional layered architectures and as coatings for individual cells to deliver tunable payloads of drugs or bioactive molecules. This review focuses on literature related to the modulation of chemical and physical properties of PEMs for tissue engineering applications and recent research efforts in maintaining and directing cellular phenotype in stem cell differentiation.
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Affiliation(s)
- Christopher J. Detzel
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Adam L. Larkin
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - Padmavathy Rajagopalan
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
- ICTAS Center for Systems Biology of Engineered Tissues, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
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