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Cheng KKW, Fingerhut L, Duncan S, Prajna NV, Rossi AG, Mills B. In vitro and ex vivo models of microbial keratitis: Present and future. Prog Retin Eye Res 2024; 102:101287. [PMID: 39004166 DOI: 10.1016/j.preteyeres.2024.101287] [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: 04/03/2024] [Revised: 07/09/2024] [Accepted: 07/10/2024] [Indexed: 07/16/2024]
Abstract
Microbial keratitis (MK) is an infection of the cornea, caused by bacteria, fungi, parasites, or viruses. MK leads to significant morbidity, being the fifth leading cause of blindness worldwide. There is an urgent requirement to better understand pathogenesis in order to develop novel diagnostic and therapeutic approaches to improve patient outcomes. Many in vitro, ex vivo and in vivo MK models have been developed and implemented to meet this aim. Here, we present current in vitro and ex vivo MK model systems, examining their varied design, outputs, reporting standards, and strengths and limitations. Major limitations include their relative simplicity and the perceived inability to study the immune response in these MK models, an aspect widely accepted to play a significant role in MK pathogenesis. Consequently, there remains a dependence on in vivo models to study this aspect of MK. However, looking to the future, we draw from the broader field of corneal disease modelling, which utilises, for example, three-dimensional co-culture models and dynamic environments observed in bioreactors and organ-on-a-chip scenarios. These remain unexplored in MK research, but incorporation of these approaches will offer further advances in the field of MK corneal modelling, in particular with the focus of incorporation of immune components which we anticipate will better recapitulate pathogenesis and yield novel findings, therefore contributing to the enhancement of MK outcomes.
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Affiliation(s)
- Kelvin Kah Wai Cheng
- Centre for Inflammation Research, Institute of Regeneration and Repair, University of Edinburgh, United Kingdom
| | - Leonie Fingerhut
- Centre for Inflammation Research, Institute of Regeneration and Repair, University of Edinburgh, United Kingdom
| | - Sheelagh Duncan
- Centre for Inflammation Research, Institute of Regeneration and Repair, University of Edinburgh, United Kingdom
| | - N Venkatesh Prajna
- Department of Cornea and Refractive Surgery Services, Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, Madurai, Tamil Nadu, India
| | - Adriano G Rossi
- Centre for Inflammation Research, Institute of Regeneration and Repair, University of Edinburgh, United Kingdom
| | - Bethany Mills
- Centre for Inflammation Research, Institute of Regeneration and Repair, University of Edinburgh, United Kingdom.
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Karimi A, Crouch DJ, Razaghi R, Crawford Downs J, Acott TS, Kelley MJ, Behnsen JG, Bosworth LA, Sheridan CM. Morphological and biomechanical analyses of the human healthy and glaucomatous aqueous outflow pathway: Imaging-to-modeling. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 236:107485. [PMID: 37149973 DOI: 10.1016/j.cmpb.2023.107485] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/09/2023] [Accepted: 03/13/2023] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND OBJECTIVE Intraocular pressure (IOP) is maintained via a dynamic balance between the production of aqueous humor and its drainage through the trabecular meshwork (TM), juxtacanalicular connective tissue (JCT), and Schlemm's canal (SC) endothelium of the conventional outflow pathway. Primary open angle glaucoma (POAG) is often associated with IOP elevation that occurs due to an abnormally high outflow resistance across the outflow pathway. Outflow tissues are viscoelastic and actively interact with aqueous humor dynamics through a two-way fluid-structure interaction coupling. While glaucoma affects the morphology and stiffness of the outflow tissues, their biomechanics and hydrodynamics in glaucoma eyes remain largely unknown. This research aims to develop an image-to-model method allowing the biomechanics and hydrodynamics of the conventional aqueous outflow pathway to be studied. METHODS We used a combination of X-ray computed tomography and scanning electron microscopy to reconstruct high-fidelity, eye-specific, 3D microstructural finite element models of the healthy and glaucoma outflow tissues in cellularized and decellularized conditions. The viscoelastic TM/JCT/SC complex finite element models with embedded viscoelastic beam elements were subjected to a physiological IOP load boundary; the stresses/strains and the flow state were calculated using fluid-structure interaction and computational fluid dynamics. RESULTS Based on the resultant hydrodynamics parameters across the outflow pathway, the primary site of outflow resistance in healthy eyes was in the JCT and immediate vicinity of the SC inner wall, while the majority of the outflow resistance in the glaucoma eyes occurred in the TM. The TM and JCT in the glaucoma eyes showed 1.32-fold and 1.13-fold larger beam thickness and smaller trabecular space size (2.24-fold and 1.50-fold) compared to the healthy eyes. CONCLUSIONS Characterizing the accurate morphology of the outflow tissues may significantly contribute to constructing more accurate, robust, and reliable models, that can eventually help to better understand the dynamic IOP regulation, hydrodynamics of the aqueous humor, and outflow resistance dynamic in the human eyes. This model demonstrates proof of concept for determining changes to outflow resistance in healthy and glaucomatous tissues and thus may be utilized in larger cohorts of donor tissues where disease specificity, race, age, and gender of the eye donors may be accounted for.
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Affiliation(s)
- Alireza Karimi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Devon J Crouch
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L7 8TX, United Kingdom
| | - Reza Razaghi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, United States
| | - J Crawford Downs
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ted S Acott
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States; Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon, United States
| | - Mary J Kelley
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States; Department of Integrative Biosciences, Oregon Health & Science University, Portland, Oregon, United States
| | - Julia G Behnsen
- Department of Mechanical, Materials, and Aerospace Engineering, University of Liverpool, Liverpool, L69 6GB, United Kingdom
| | - Lucy A Bosworth
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L7 8TX, United Kingdom
| | - Carl M Sheridan
- Department of Eye and Vision Science, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L7 8TX, United Kingdom.
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Wang T, Pattabiraman PP. Analysis of Lipid Contents in Human Trabecular Meshwork Cells by Multiple Reaction Monitoring (MRM) Profiling Lipidomics. Methods Mol Biol 2023; 2625:291-298. [PMID: 36653651 DOI: 10.1007/978-1-0716-2966-6_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Lipids are among the major constituents of cells and play many important cellular functions. Lipid levels in the trabecular meshwork (TM) aqueous humor outflow pathway play an important role in the maintenance of aqueous humor drainage and intraocular pressure (IOP) homeostasis. Therefore, it is important to characterize the changes in the lipid contents in the aqueous humor outflow pathway tissues to better understand their functional significance in the maintenance of IOP. The multiple reaction monitoring (MRM)-based profiling aids in the analysis of the metabolome as a collection of functional groups and is utilized as an exploratory metabolomics and lipidomics approach. The MRM-based profiling utilizes tandem mass spectrometry experiments carried out on a commercial triple quadrupole mass spectrometer with three aligned quadrupole mass filters (Q1, Q2, and Q3). This screening methodology can be utilized for targeted lipidomics screening. This chapter focuses on the methodology for isolation and culturing of the TM cells, lipid extraction, and the MRM-based lipidomics approach with data analysis.
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Affiliation(s)
- Ting Wang
- Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USA.,Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Padmanabhan Paranji Pattabiraman
- Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USA. .,Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA.
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Karimi A, Razaghi R, Rahmati SM, Downs JC, Acott TS, Kelley MJ, Wang RK, Johnstone M. The Effect of Intraocular Pressure Load Boundary on the Biomechanics of the Human Conventional Aqueous Outflow Pathway. Bioengineering (Basel) 2022; 9:672. [PMID: 36354583 PMCID: PMC9687513 DOI: 10.3390/bioengineering9110672] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 10/28/2022] [Accepted: 11/08/2022] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND Aqueous humor outflow resistance in the trabecular meshwork (TM), juxtacanalicular connective tissue (JCT), and Schlemm's canal (SC) endothelium of the conventional outflow pathway actively contribute to intraocular pressure (IOP) regulation. Outflow resistance is actively affected by the dynamic outflow pressure gradient across the TM, JCT, and SC inner wall tissues. The resistance effect implies the presence of a fluid-structure interaction (FSI) coupling between the outflow tissues and the aqueous humor. However, the biomechanical interactions between viscoelastic outflow tissues and aqueous humor dynamics are largely unknown. METHODS A 3D microstructural finite element (FE) model of a healthy human eye TM/JCT/SC complex was constructed with elastic and viscoelastic material properties for the bulk extracellular matrix and embedded elastic cable elements. The FE models were subjected to both idealized and a physiologic IOP load boundary using the FSI method. RESULTS The elastic material model for both the idealized and physiologic IOP load boundary at equal IOPs showed similar stresses and strains in the outflow tissues as well as pressure in the aqueous humor. However, outflow tissues with viscoelastic material properties were sensitive to the IOP load rate, resulting in different mechanical and hydrodynamic responses in the tissues and aqueous humor. CONCLUSIONS Transient IOP fluctuations may cause a relatively large IOP difference of ~20 mmHg in a very short time frame of ~0.1 s, resulting in a rate stiffening in the outflow tissues. Rate stiffening reduces strains and causes a rate-dependent pressure gradient across the outflow tissues. Thus, the results suggest it is necessary to use a viscoelastic material model in outflow tissues that includes the important role of IOP load rate.
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Affiliation(s)
- Alireza Karimi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Reza Razaghi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | | | - J. Crawford Downs
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Ted S. Acott
- Departments of Ophthalmology and Biochemistry and Molecular Biology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Mary J. Kelley
- Departments of Ophthalmology and Integrative Biosciences, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Ruikang K. Wang
- Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Murray Johnstone
- Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA
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5
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Karimi A, Razaghi R, Padilla S, Rahmati SM, Downs JC, Acott TS, Kelley MJ, Wang RK, Johnstone M. Viscoelastic Biomechanical Properties of the Conventional Aqueous Outflow Pathway Tissues in Healthy and Glaucoma Human Eyes. J Clin Med 2022; 11:6049. [PMID: 36294371 PMCID: PMC9605362 DOI: 10.3390/jcm11206049] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/11/2022] [Accepted: 10/12/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Although the tissues comprising the ocular conventional outflow pathway have shown strong viscoelastic mechanical response to aqueous humor pressure dynamics, the viscoelastic mechanical properties of the trabecular meshwork (TM), juxtacanalicular connective tissue (JCT), and Schlemm's canal (SC) inner wall are largely unknown. METHODS A quadrant of the anterior segment from two human donor eyes at low- and high-flow (LF and HF) outflow regions was pressurized and imaged using optical coherence tomography (OCT). A finite element (FE) model of the TM, the adjacent JCT, and the SC inner wall was constructed and viscoelastic beam elements were distributed in the extracellular matrix (ECM) of the TM and JCT to represent anisotropic collagen. An inverse FE-optimization algorithm was used to calculate the viscoelastic properties of the ECM/beam elements such that the TM/JCT/SC model and OCT imaging data best matched over time. RESULTS The ECM of the glaucoma tissues showed significantly larger time-dependent shear moduli compared to the heathy tissues. Significantly larger shear moduli were also observed in the LF regions of both the healthy and glaucoma eyes compared to the HF regions. CONCLUSIONS The outflow tissues in both glaucoma eyes and HF regions are stiffer and less able to respond to dynamic IOP.
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Affiliation(s)
- Alireza Karimi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Reza Razaghi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Steven Padilla
- Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA
| | | | - J. Crawford Downs
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Ted S. Acott
- Departments of Ophthalmology and Biochemistry and Molecular Biology, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Mary J. Kelley
- Departments of Ophthalmology and Integrative Biosciences, Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Ruikang K. Wang
- Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
| | - Murray Johnstone
- Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA
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Lommatzsch C, Rothaus K, Schopmeyer L, Feldmann M, Bauer D, Grisanti S, Heinz C, Kasper M. Elevated endothelin-1 levels as risk factor for an impaired ocular blood flow measured by OCT-A in glaucoma. Sci Rep 2022; 12:11801. [PMID: 35821224 PMCID: PMC9276731 DOI: 10.1038/s41598-022-15401-5] [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: 02/10/2022] [Accepted: 06/23/2022] [Indexed: 11/28/2022] Open
Abstract
The purpose of this study was to ascertain whether a correlation exists between glaucoma-associated alteration of ocular vascular haemodynamics and endothelin-1 (ET-1) levels exist. Eyes of patients with cataract (n = 30) or glaucoma (n = 68) were examined with optical coherence tomography (OCT) and OCT-angiography (OCT-A; AngioVue™-RTVue-XR; Optovue, Fremont, California, USA). The peripapillary and the macular vessel density (VD) values were measured. Inferior and superior retinal nerve fibre layer (RNFL) thickness loss was used for further OCT staging. Aqueous humour of the examined eye and plasma were sampled during cataract or glaucoma surgery and analysed by means of ELISA to determine their ET-1 level. Glaucoma eyes are characterised by reductions in RNFL thickness and VD that correlate significantly with the OCT GSS score. Peripheral and ocular ET-1 level were significantly elevated in patients with glaucoma and correlate positively with the OCT-GSS score of the entire study population. Peripapillary and macula VD of glaucoma patients correlates negatively with plasma ET-1 levels. Multivariable analysis showed a subordinate role of intraocular pressure predictive factor for impaired retinal blood flow compared with plasma ET-1 level in glaucoma. Peripheral ET-1 level serves as risk factor for detection of ocular blood flow changes in the optic nerve head region of glaucomatous eyes.
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Affiliation(s)
- Claudia Lommatzsch
- Department of Ophthalmology and Ophtha Lab at St. Franziskus Hospital, Hohenzollernring 74, 48145, Muenster, Germany. .,Department of Ophthalmology, University of Luebeck, Luebeck, Germany.
| | - Kai Rothaus
- Department of Ophthalmology and Ophtha Lab at St. Franziskus Hospital, Hohenzollernring 74, 48145, Muenster, Germany
| | | | - Maria Feldmann
- Department of Ophthalmology, Braunschweig Hospital, Braunschweig, Germany
| | - Dirk Bauer
- Department of Ophthalmology and Ophtha Lab at St. Franziskus Hospital, Hohenzollernring 74, 48145, Muenster, Germany
| | - Swaantje Grisanti
- Department of Ophthalmology, University of Luebeck, Luebeck, Germany
| | - Carsten Heinz
- Department of Ophthalmology and Ophtha Lab at St. Franziskus Hospital, Hohenzollernring 74, 48145, Muenster, Germany.,Department of Ophthalmology, University of Essen, Essen, Germany
| | - Maren Kasper
- Department of Ophthalmology and Ophtha Lab at St. Franziskus Hospital, Hohenzollernring 74, 48145, Muenster, Germany
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7
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Callaghan B, Lester K, Lane B, Fan X, Goljanek-Whysall K, Simpson DA, Sheridan C, Willoughby CE. Genome-wide transcriptome profiling of human trabecular meshwork cells treated with TGF-β2. Sci Rep 2022; 12:9564. [PMID: 35689009 PMCID: PMC9187693 DOI: 10.1038/s41598-022-13573-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 05/13/2022] [Indexed: 12/30/2022] Open
Abstract
Glaucoma is a complex neurodegenerative disease resulting in progressive optic neuropathy and is a leading cause of irreversible blindness worldwide. Primary open angle glaucoma (POAG) is the predominant form affecting 65.5 million people globally. Despite the prevalence of POAG and the identification of over 120 glaucoma related genetic loci, the underlaying molecular mechanisms are still poorly understood. The transforming growth factor beta (TGF-β) signalling pathway is implicated in the molecular pathology of POAG. To gain a better understanding of the role TGF-β2 plays in the glaucomatous changes to the molecular pathology in the trabecular meshwork, we employed RNA-Seq to delineate the TGF-β2 induced changes in the transcriptome of normal primary human trabecular meshwork cells (HTM). We identified a significant number of differentially expressed genes and associated pathways that contribute to the pathogenesis of POAG. The differentially expressed genes were predominantly enriched in ECM regulation, TGF-β signalling, proliferation/apoptosis, inflammation/wound healing, MAPK signalling, oxidative stress and RHO signalling. Canonical pathway analysis confirmed the enrichment of RhoA signalling, inflammatory-related processes, ECM and cytoskeletal organisation in HTM cells in response to TGF-β2. We also identified novel genes and pathways that were affected after TGF-β2 treatment in the HTM, suggesting additional pathways are activated, including Nrf2, PI3K-Akt, MAPK and HIPPO signalling pathways. The identification and characterisation of TGF-β2 dependent differentially expressed genes and pathways in HTM cells is essential to understand the patho-physiology of glaucoma and to develop new therapeutic agents.
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Affiliation(s)
- Breedge Callaghan
- Genomic Medicine Group, Biomedical Sciences Research Institute, Ulster University, Coleraine, BT52 1SA, Northern Ireland, UK
| | - Karen Lester
- Genomic Medicine Group, Biomedical Sciences Research Institute, Ulster University, Coleraine, BT52 1SA, Northern Ireland, UK.,Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK
| | - Brian Lane
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK.,Translational Radiobiology Group, Division of Cancer Sciences, University of Manchester, Manchester Academic Health Science Centre, Christie NHS Foundation Trust Hospital, Manchester, M20 4BX, UK
| | - Xiaochen Fan
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK
| | - Katarzyna Goljanek-Whysall
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK.,School of Medicine, Physiology, National University of Ireland Galway, Galway, H91 W5P7, Ireland
| | - David A Simpson
- The Wellcome - Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University, Belfast, UK
| | - Carl Sheridan
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK
| | - Colin E Willoughby
- Genomic Medicine Group, Biomedical Sciences Research Institute, Ulster University, Coleraine, BT52 1SA, Northern Ireland, UK. .,Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK.
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Karimi A, Razaghi R, Rahmati SM, Downs JC, Acott TS, Wang RK, Johnstone M. Modeling the biomechanics of the conventional aqueous outflow pathway microstructure in the human eye. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 221:106922. [PMID: 35660940 PMCID: PMC10424784 DOI: 10.1016/j.cmpb.2022.106922] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/16/2022] [Accepted: 05/26/2022] [Indexed: 05/27/2023]
Abstract
BACKGROUND AND OBJECTIVE Intraocular pressure (IOP) is determined by aqueous humor outflow resistance, which is a function of the combined resistance of Schlemm's canal (SC) endothelium and the trabecular meshwork (TM) and their interactions in the juxtacanalicular connective tissue (JCT) region. Aqueous outflow in the conventional outflow pathway results in pressure gradient across the TM, JCT, and SC inner wall, and induces mechanical stresses and strains that influence the geometry and homeostasis of the outflow system. The outflow resistance is affected by alteration in tissues' geometry, so there is potential for active, two-way, fluid-structure interaction (FSI) coupling between the aqueous humor (fluid) and the TM, JCT, and SC inner wall (structure). However, our understanding of the biomechanical interactions of the aqueous humor with the outflow connective tissues and its contribution to the outflow resistance regulation is incomplete. METHODS In this study, a microstructural finite element (FE) model of a human eye TM, JCT, and SC inner wall was constructed from a segmented, high-resolution histologic 3D reconstruction of the human outflow system. Three different elastic moduli (0.004, 0.128, and 51.5 MPa based on prior reports) were assigned to the TM/JCT complex while the elastic modulus of the SC inner wall was kept constant at 0.00748 MPa. The hydraulic conductivity was programmed separately for the TM, JCT, and SC inner wall using a custom subroutine. Cable elements were embedded into the TM and JCT extracellular matrix to represent the directional stiffness imparted by anisotropic collagen fibril orientation. The resultant stresses and strains in the outflow system were calculated using fluid-structure interaction method. RESULTS The higher TM/JCT stiffness resulted in larger stresses, but smaller strains in the outflow connective tissues, and resulted in a 4- and 5-fold larger pressure drop across the SC inner wall, respectively, compared to the most compliant model. Funneling through µm-sized SC endothelial pores was evident in the models at lower tissue stiffness, but aqueous flow was more turbulent in models with higher TM/JCT stiffness. CONCLUSIONS The mechanical properties of the outflow tissues play a crucial role in the hydrodynamics of the aqueous humor in the conventional outflow system.
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Affiliation(s)
- Alireza Karimi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, 1670 University Boulevard, VH 372B, Birmingham, AL 35294, USA.
| | - Reza Razaghi
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, 1670 University Boulevard, VH 372B, Birmingham, AL 35294, USA
| | | | - J Crawford Downs
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, 1670 University Boulevard, VH 372B, Birmingham, AL 35294, USA
| | - Ted S Acott
- Ophthalmology and Biochemistry and Molecular Biology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - Ruikang K Wang
- Department of Ophthalmology, University of Washington, Seattle, WA, USA; Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Murray Johnstone
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
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9
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Mechanical stretch induces Ca 2+ influx and extracellular release of PGE 2 through Piezo1 activation in trabecular meshwork cells. Sci Rep 2021; 11:4044. [PMID: 33597646 PMCID: PMC7890064 DOI: 10.1038/s41598-021-83713-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/01/2021] [Indexed: 11/22/2022] Open
Abstract
The trabecular meshwork (TM) constitutes the main pathway for aqueous humor drainage and is exposed to complex intraocular pressure fluctuations. The mechanism of homeostasis in which TM senses changes in intraocular pressure and leads to normal levels of outflow resistance is not yet well understood. Previous reports have shown that Piezo1, a mechanically-activated cation channel, is expressed in TM and isolated TM cells. Therefore, we tested hypothesis that Piezo1 may function in response to membrane tension and stretch in TM. In human trabecular meshwork (hTM) cells, PIEZO1 was showed to be abundantly expressed, and Piezo1 agonist Yoda1 and mechanical stretch caused a Piezo1-dependent Ca2+ influx and release of arachidonic acid and PGE2. Treatment with Yoda1 or PGE2 significantly inhibited hTM cell contraction. These results suggest that mechanical stretch stimuli in TM activates Piezo1 and subsequently regulates TM cell contraction by triggering Ca2+ influx and release of arachidonic acid and PGE2. Thus, Piezo1 could acts as a regulator of intraocular pressure (IOP) within the conventional outflow pathway and could be a novel therapeutic strategy to modulate IOP in glaucoma patients.
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10
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Reina-Torres E, De Ieso ML, Pasquale LR, Madekurozwa M, van Batenburg-Sherwood J, Overby DR, Stamer WD. The vital role for nitric oxide in intraocular pressure homeostasis. Prog Retin Eye Res 2020; 83:100922. [PMID: 33253900 DOI: 10.1016/j.preteyeres.2020.100922] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/13/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023]
Abstract
Catalyzed by endothelial nitric oxide (NO) synthase (eNOS) activity, NO is a gaseous signaling molecule maintaining endothelial and cardiovascular homeostasis. Principally, NO regulates the contractility of vascular smooth muscle cells and permeability of endothelial cells in response to either biochemical or biomechanical cues. In the conventional outflow pathway of the eye, the smooth muscle-like trabecular meshwork (TM) cells and Schlemm's canal (SC) endothelium control aqueous humor outflow resistance, and therefore intraocular pressure (IOP). The mechanisms by which outflow resistance is regulated are complicated, but NO appears to be a key player as enhancement or inhibition of NO signaling dramatically affects outflow function; and polymorphisms in NOS3, the gene that encodes eNOS modifies the relation between various environmental exposures and glaucoma. Based upon a comprehensive review of past foundational studies, we present a model whereby NO controls a feedback signaling loop in the conventional outflow pathway that is sensitive to changes in IOP and its oscillations. Thus, upon IOP elevation, the outflow pathway tissues distend, and the SC lumen narrows resulting in increased SC endothelial shear stress and stretch. In response, SC cells upregulate the production of NO, relaxing neighboring TM cells and increasing permeability of SC's inner wall. These IOP-dependent changes in the outflow pathway tissues reduce the resistance to aqueous humor drainage and lower IOP, which, in turn, diminishes the biomechanical signaling on SC. Similar to cardiovascular pathogenesis, dysregulation of the eNOS/NO system leads to dysfunctional outflow regulation and ocular hypertension, eventually resulting in primary open-angle glaucoma.
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Affiliation(s)
| | | | - Louis R Pasquale
- Eye and Vision Research Institute of New York Eye and Ear Infirmary at Mount Sinai, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | | | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, UK.
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, NC, USA.
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11
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Cai J, Perkumas K, Stamer WD, Liu Y. An In Vitro Bovine Cellular Model for Human Schlemm's Canal Endothelial Cells and Their Response to TGFβ Treatment. Transl Vis Sci Technol 2020; 9:32. [PMID: 32832237 PMCID: PMC7414733 DOI: 10.1167/tvst.9.7.32] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/17/2020] [Indexed: 12/12/2022] Open
Abstract
Purpose Due to the limited availability of primary human Schlemm's canal (SC) endothelial cells, we aimed to develop an in vitro cellular model using the angular aqueous plexus (AAP) cells from bovine eyes. Methods We harvested a mixture of cells from the trabecular meshwork region including AAP loops from multiple donors, followed by puromycin treatment and immunostaining of Von Willebrand factor and vascular endothelial (VE)-cadherin to confirm identity. Previously identified differentially expressed genes in glaucomatous SC cells were examined in non-glaucomatous SC cells (n = 3) under 0% or 15% equibiaxial strain for 24 hours using droplet digital polymerase chain reaction (ddPCR) and analyzed using the Ingenuity Pathway Analysis (IPA) software application to identify upstream regulators. To compare the cellular responses to candidate regulators of these mechanoresponsive genes, AAP and human SC cells (n = 3) were treated with 5 or 10 ng/mL transforming growth factor beta-2 (TGFβ2) for 24 or 48 hours, followed with expression profiling using real-time PCR or ddPCR. Results We found that the isolated AAP cells displayed uniform cobblestone-like morphology and positive expression of two endothelial markers. In stretched SC cells, nine glaucoma-related genes were upregulated, and IPA implicated TGFβ as a potential upstream regulator. The effects of TGFβ2 treatment were similar for both AAP and SC cells in a dose- and time-dependent manner, activating TGFBR1 and SMAD2, inhibiting BMP4, and altering expression of three glaucoma-related genes (DCN,EZR, and CYP1B1). Conclusions Bovine AAP cells may serve as an alternative cellular model of human SC cells. Translational Relevance These AAP cells may be used to study the functional pathways related to the outflow facility.
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Affiliation(s)
- Jingwen Cai
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | | | - W. Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, NC, USA
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Yutao Liu
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
- James & Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
- Center for Biotechnology and Genomic Medicine, Augusta University, Augusta, GA, USA
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12
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Kang HG, Kim JW. Effect of Minoxidil on Trabecular Outflow via the Paracellular Pathway. KOREAN JOURNAL OF OPHTHALMOLOGY 2020; 34:97-105. [PMID: 32233142 PMCID: PMC7105781 DOI: 10.3341/kjo.2019.0124] [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: 10/09/2019] [Revised: 10/25/2019] [Accepted: 11/14/2019] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To investigate the pathway and effects of minoxidil on trabecular outflow in cultured human trabecular meshwork (TM) cells. METHODS After exposing primarily cultured TM cells to 0, 10, 50, or 100 μM minoxidil sulfate (MS), trabecular outflow was assessed by measuring TM cell monolayer permeability to carboxyfluorescein and transepithelial electrical resistance. To assess the pathway of permeability changes, caveolin-1, occludin, and claudin-5 levels were measured via western blot. Generation of reactive oxygen species (ROS) was measured using the dichlorofluorescein diacetate assay. To assess the involvement of nitric oxide (NO) in minoxidil-induced permeability increase, the degrees of endothelial nitric oxide synthase mRNA expression and NO production were measured with reverse transcription polymerase chain reaction and Griess assays, respectively. Permeability was also measured with co-exposure to 50 μM N-acetyl cysteine. RESULTS MS significantly increased TM cell monolayer permeability (p < 0.05) and decreased transepithelial electrical resistance (p < 0.05). MS decreased the degree of endothelial nitric oxide synthase mRNA expression but did not affect NO production. MS decreased occludin and claudin-5 levels but did not affect caveolin-1 level. MS at 100 μM increased the generation of ROS, and MS-induced permeability increase was attenuated after co-exposure to 50 μM N-acetyl cysteine. CONCLUSIONS Minoxidil may preferentially increase trabecular permeability via a paracellular pathway by downregulation of tight junction proteins. This minoxidil-induced permeability through the TM may be mediated by generation of ROS.
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Affiliation(s)
| | - Jae Woo Kim
- Department of Ophthalmology, Daegu Catholic University School of Medicine, Daegu, Korea.
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13
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Hou Z, Li C, Liu Y, Zhang M, Wang Y, Fan Z, Guo C, Lin B, Liu Y. Design, synthesis and biological evaluation of carbohydrate-based sulphonamide derivatives as topical antiglaucoma agents through selective inhibition of carbonic anhydrase II. J Enzyme Inhib Med Chem 2020; 35:383-390. [PMID: 31865756 PMCID: PMC6968511 DOI: 10.1080/14756366.2019.1705293] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
A series of new carbohydrate-based sulphonamide derivatives were designed, synthesised by employing the so-call ‘sugar-tail’ approach. The compounds were evaluated in vitro against a panel of CAs. Compared to their parent compound p-sulfamoylbenzoic acid, these compounds showed nearly 100-fold improvement in their binding affinities against hCA II in vitro. All of compounds showed great water solubility and the pH value of their water solutions of compounds is 7.0. Such properties are advantageous to make them much less irritating to the eye when applied topical glaucomatous drugs, compared to the relatively highly acidic dorzolamide preparations (pH 5.5). Notably, compounds 7d, 7 g, 7 h demonstrated to topically lower intraocular pressure (IOP) in glaucomatous animals better than brinzolamide when applied as a 1% solution directly into the eye. Low cytotoxicity on human cornea epithelial cell was observed in the tested concentrations by the MTT assay.
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Affiliation(s)
- Zhuang Hou
- Key Laboratory of Structure-Based Drugs Design and Discovery (Ministry of Education), School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, China
| | - Chuanchao Li
- Key Laboratory of Structure-Based Drugs Design and Discovery (Ministry of Education), School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, China
| | - Yichuang Liu
- Key Laboratory of Structure-Based Drugs Design and Discovery (Ministry of Education), School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, China
| | - Miao Zhang
- Key Laboratory of Structure-Based Drugs Design and Discovery (Ministry of Education), School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, China
| | - Yitong Wang
- Key Laboratory of Structure-Based Drugs Design and Discovery (Ministry of Education), School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, China
| | - Zhanfang Fan
- Key Laboratory of Structure-Based Drugs Design and Discovery (Ministry of Education), School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, China
| | - Chun Guo
- Key Laboratory of Structure-Based Drugs Design and Discovery (Ministry of Education), School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, China
| | - Bin Lin
- Key Laboratory of Structure-Based Drugs Design and Discovery (Ministry of Education), School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, China
| | - Yang Liu
- Key Laboratory of Structure-Based Drugs Design and Discovery (Ministry of Education), School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, Shenyang, China
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14
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Nagano N, Honjo M, Kawaguchi M, Nishimasu H, Nureki O, Kano K, Aoki J, Komatsu T, Okabe T, Kojima H, Nagano T, Aihara M. Development of a Novel Intraocular-Pressure-Lowering Therapy Targeting ATX. Biol Pharm Bull 2019; 42:1926-1935. [DOI: 10.1248/bpb.b19-00567] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Norimichi Nagano
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo
| | - Megumi Honjo
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo
| | | | | | - Osamu Nureki
- Graduate School of Science, The University of Tokyo
| | - Kuniyuki Kano
- Graduate School of Pharmaceutical Sciences, Tohoku University
- Core Research for Evolutional Science and Technology (CREST)
| | - Junken Aoki
- Graduate School of Pharmaceutical Sciences, Tohoku University
- Core Research for Evolutional Science and Technology (CREST)
| | - Toru Komatsu
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
| | | | | | | | - Makoto Aihara
- Department of Ophthalmology, Graduate School of Medicine, The University of Tokyo
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15
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Measuring changes in Schlemm's canal and trabecular meshwork in different accommodation states in myopia children: an observational study. Eye (Lond) 2019; 34:374-382. [PMID: 31399701 DOI: 10.1038/s41433-019-0548-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 07/03/2019] [Accepted: 07/08/2019] [Indexed: 02/04/2023] Open
Abstract
PURPOSE The aim of the study was to evaluate changes in size of Schlemm's canal (SC) and trabecular meshwork(TM) in response to accommodation stimuli and cycloplegia states in myopia children. METHODS In total, 34 children were enroled in this study. A -6.0 D accommodation stimulus was achieved by looking at an optotype through a mirror. Cycloplegia state was induced with 1% tropicamide. Two states were confirmed by measuring the central lens thickness (CLT), anterior chamber depth and pupil diameter. The size of SC and TM was measured using swept-source optical coherence tomography. The association between changes in SC size and CLT was analysed. RESULTS Compared with that in the relaxation state, SC size increased significantly under -6.0 D accommodation stimuli. SC area (SCA) increased from 6371 ± 2517 μm2 to 7824 ± 2727 μm2, SC length (SCL) from 249 ± 10 μm to 295 ± 12 μm and SC width (SCW) from 27 ± 9 μm to 31 ± 8 μm. Under the cycloplegia state, SCA decreased to 5009 ± 2028 μm2; SCL to 212 ± 14 μm, and SCW to 22 ± 5 μm. Changes in SCA (r = 0.35, P = 0.0007), SCL (r = 0.251, P = 0.0172) and SCW (r = 0.253, P = 0.016) were significantly correlated with changes in CLT. TM size was not significantly altered compared to that in the relaxation state. TM length (TML) increased from 562 ± 45 μm to 587 ± 47 μm after exposure to -6.0 D accommodation stimulus. CONCLUSION SC size enlarged in response to -6.0 D accommodation stimuli and shrunk under cycloplegia. TM length increased under the accommodation stimulus state.
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16
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Pavlenko TA, Kim AR, Kurina AY, Davydova NG, Kolomojceva EM, Chesnokova NB, Ugrumov MV. [Endothelins and dopamine levels in tears for assessment of neurovascular disorders in glaucoma]. Vestn Oftalmol 2018; 134:41-46. [PMID: 30166509 DOI: 10.17116/oftalma201813404141] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
PURPOSE To estimate the possibility of detection of neurovascular ocular disorders in glaucoma by assessing the content of catecholamines and endothelins in lacrimal fluid. MATERIAL AND METHODS The study included 47 patients with primary open-angle glaucoma (POAG). Tear eluate was analyzed by high performance liquid chromatography (HPLC) for catecholamines concentrations, and enzyme-linked immunoassay (ELISA) was used for evaluation of endothelins content. RESULTS Endothelin-1 (ET-1) and big endothelin (bET) content in tears of patients with POAG was higher than in healthy controls. Concentration of dopamine (DA) in tears was lower and concentrations of L-dioxyphenylalanine and dihydroxyphenylacetic acid had a tendency for decrease. Noradrenaline content was equal in patients with POAG and controls. Adrenaline was not detected in any tear samples. CONCLUSION Multidirectional changes of endothelins and DA levels in tears of patients with POAG was found. The increased concentration of ET-1 and its precursor bET promote vasoconstriction and decrease of aqueous humor outflow. The decrease of DA concentration is typical for neurodegenerative processes. Estimation of DA and endothelins concentrations in tears can enable early detection of neurovascular disorders in glaucoma patients and help evaluate their severity.
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Affiliation(s)
- T A Pavlenko
- Moscow Helmholtz Research Institute of Eye Diseases, 14/19 Sadovaya-Chernogryazskaya St., Moscow, Russian Federation, 105062
| | - A R Kim
- Koltzov Institute of Developmental Biology, 26 Vavilova St., Moscow, Russian Federation, 119334
| | - A Yu Kurina
- Koltzov Institute of Developmental Biology, 26 Vavilova St., Moscow, Russian Federation, 119334
| | - N G Davydova
- Moscow Helmholtz Research Institute of Eye Diseases, 14/19 Sadovaya-Chernogryazskaya St., Moscow, Russian Federation, 105062
| | - E M Kolomojceva
- Moscow Helmholtz Research Institute of Eye Diseases, 14/19 Sadovaya-Chernogryazskaya St., Moscow, Russian Federation, 105062
| | - N B Chesnokova
- Moscow Helmholtz Research Institute of Eye Diseases, 14/19 Sadovaya-Chernogryazskaya St., Moscow, Russian Federation, 105062
| | - M V Ugrumov
- Koltzov Institute of Developmental Biology, 26 Vavilova St., Moscow, Russian Federation, 119334
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17
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Xu L, Zhang Y, Guo R, Shen W, Qi Y, Wang Q, Guo Z, Qi C, Yin H, Wang J. HES1 promotes extracellular matrix protein expression and inhibits proliferation and migration in human trabecular meshwork cells under oxidative stress. Oncotarget 2017; 8:21818-21833. [PMID: 28423527 PMCID: PMC5400626 DOI: 10.18632/oncotarget.15631] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/07/2017] [Indexed: 01/06/2023] Open
Abstract
Glaucoma is the leading cause of irreversible blindness. The most prevalent form of glaucoma is primary open-angle glaucoma (POAG). Oxidative stress is one of the major pathogenic factors of the POAG, and can elicit molecular and functional changes in trabecular meshwork cells, causing increased aqueous humor outflow resistance and elevated intraocular pressure. However, the regulatory mechanisms underlying oxidative stress-induced cell phenotypic changes remain elusive. Herein, we exposed primary human trabecular meshwork cells to the oxidative stress induced by 300 μM H2O2 for 2 h, and found significantly up-regulated expression of extracellular matrix proteins and a transcription factor, hairy and enhancer of split-1 (HES1). The cell functions, including migration and proliferation, were impaired by the oxidative stress. Furthermore, HES1 shRNA abrogated the extracellular matrix protein up-regulation and rescued the functional defects caused by the oxidative stress; conversely, HES1 overexpression resulted in the molecular and functional changes similar to those induced by H2O2. These results suggest that HES1 promotes extracellular matrix protein expression and inhibits proliferative and migratory functions in the trabecular meshwork cells under oxidative stress, thereby providing a novel pathogenic mechanism underlying and a potential therapeutic target to the POAG.
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Affiliation(s)
- Linqi Xu
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute, College of Optometry and Ophthalmology, Tianjin Medical University, Tianjin 300384, China.,Tianjin Research Center of Basic Medical Sciences and Department of Cell Biology, Tianjin Medical University, Tianjin 300070, China
| | - Yan Zhang
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute, College of Optometry and Ophthalmology, Tianjin Medical University, Tianjin 300384, China
| | - Ruru Guo
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute, College of Optometry and Ophthalmology, Tianjin Medical University, Tianjin 300384, China
| | - Wencui Shen
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute, College of Optometry and Ophthalmology, Tianjin Medical University, Tianjin 300384, China.,Tianjin Research Center of Basic Medical Sciences and Department of Cell Biology, Tianjin Medical University, Tianjin 300070, China
| | - Yan Qi
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute, College of Optometry and Ophthalmology, Tianjin Medical University, Tianjin 300384, China.,Tianjin Research Center of Basic Medical Sciences and Department of Cell Biology, Tianjin Medical University, Tianjin 300070, China
| | - Qingsong Wang
- Tianjin Research Center of Basic Medical Sciences and Department of Cell Biology, Tianjin Medical University, Tianjin 300070, China
| | - Zhenglong Guo
- Tianjin Research Center of Basic Medical Sciences and Department of Cell Biology, Tianjin Medical University, Tianjin 300070, China
| | - Chen Qi
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute, College of Optometry and Ophthalmology, Tianjin Medical University, Tianjin 300384, China
| | - Haifang Yin
- Tianjin Research Center of Basic Medical Sciences and Department of Cell Biology, Tianjin Medical University, Tianjin 300070, China
| | - Jiantao Wang
- Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute, College of Optometry and Ophthalmology, Tianjin Medical University, Tianjin 300384, China
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18
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Huang Q, Rui EY, Cobbs M, Dinh DM, Gukasyan HJ, Lafontaine JA, Mehta S, Patterson BD, Rewolinski DA, Richardson PF, Edwards MP. Design, Synthesis, and Evaluation of NO-Donor Containing Carbonic Anhydrase Inhibitors To Lower Intraocular Pressure. J Med Chem 2015; 58:2821-33. [DOI: 10.1021/acs.jmedchem.5b00043] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Qinhua Huang
- La Jolla Laboratories, Pfizer Worldwide
Research and Development, 10770 Science
Center Drive, San Diego, California 92121, United States
| | - Eugene Y. Rui
- La Jolla Laboratories, Pfizer Worldwide
Research and Development, 10770 Science
Center Drive, San Diego, California 92121, United States
| | - Morena Cobbs
- La Jolla Laboratories, Pfizer Worldwide
Research and Development, 10770 Science
Center Drive, San Diego, California 92121, United States
| | - Dac M. Dinh
- La Jolla Laboratories, Pfizer Worldwide
Research and Development, 10770 Science
Center Drive, San Diego, California 92121, United States
| | - Hovhannes J. Gukasyan
- La Jolla Laboratories, Pfizer Worldwide
Research and Development, 10770 Science
Center Drive, San Diego, California 92121, United States
| | - Jennifer A. Lafontaine
- La Jolla Laboratories, Pfizer Worldwide
Research and Development, 10770 Science
Center Drive, San Diego, California 92121, United States
| | - Saurabh Mehta
- La Jolla Laboratories, Pfizer Worldwide
Research and Development, 10770 Science
Center Drive, San Diego, California 92121, United States
| | - Brian D. Patterson
- La Jolla Laboratories, Pfizer Worldwide
Research and Development, 10770 Science
Center Drive, San Diego, California 92121, United States
| | - David A. Rewolinski
- La Jolla Laboratories, Pfizer Worldwide
Research and Development, 10770 Science
Center Drive, San Diego, California 92121, United States
| | - Paul F. Richardson
- La Jolla Laboratories, Pfizer Worldwide
Research and Development, 10770 Science
Center Drive, San Diego, California 92121, United States
| | - Martin P. Edwards
- La Jolla Laboratories, Pfizer Worldwide
Research and Development, 10770 Science
Center Drive, San Diego, California 92121, United States
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19
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Abstract
The autonomic nervous system influences numerous ocular functions. It does this by way of parasympathetic innervation from postganglionic fibers that originate from neurons in the ciliary and pterygopalatine ganglia, and by way of sympathetic innervation from postganglionic fibers that originate from neurons in the superior cervical ganglion. Ciliary ganglion neurons project to the ciliary body and the sphincter pupillae muscle of the iris to control ocular accommodation and pupil constriction, respectively. Superior cervical ganglion neurons project to the dilator pupillae muscle of the iris to control pupil dilation. Ocular blood flow is controlled both via direct autonomic influences on the vasculature of the optic nerve, choroid, ciliary body, and iris, as well as via indirect influences on retinal blood flow. In mammals, this vasculature is innervated by vasodilatory fibers from the pterygopalatine ganglion, and by vasoconstrictive fibers from the superior cervical ganglion. Intraocular pressure is regulated primarily through the balance of aqueous humor formation and outflow. Autonomic regulation of ciliary body blood vessels and the ciliary epithelium is an important determinant of aqueous humor formation; autonomic regulation of the trabecular meshwork and episcleral blood vessels is an important determinant of aqueous humor outflow. These tissues are all innervated by fibers from the pterygopalatine and superior cervical ganglia. In addition to these classical autonomic pathways, trigeminal sensory fibers exert local, intrinsic influences on many of these regions of the eye, as well as on some neurons within the ciliary and pterygopalatine ganglia.
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Affiliation(s)
- David H McDougal
- Neurobiology of Metabolic Dysfunction Laboratory, Pennington Biomedical Research Center, USA Department of Ophthalmology, University of Alabama at Birmingham, USA
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20
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Overby DR, Bertrand J, Schicht M, Paulsen F, Stamer WD, Lütjen-Drecoll E. The structure of the trabecular meshwork, its connections to the ciliary muscle, and the effect of pilocarpine on outflow facility in mice. Invest Ophthalmol Vis Sci 2014; 55:3727-36. [PMID: 24833737 DOI: 10.1167/iovs.13-13699] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine the connections between the ciliary muscle (CM), trabecular meshwork (TM), and Schlemm's canal (SC) and their innervations that allows CM contraction (by pilocarpine) to influence conventional outflow in mice. METHODS Sequential sections and whole mounts of murine corneoscleral angles were stained for elastin, α-smooth muscle actin (αSMA), vesicular acetylcholine transporter (VAChT), neuronal nitric oxide synthase (nNOS), vasoactive intestinal peptide (VIP), and tyrosine hydroxylase (TH). Elastic (EL) fibers between the CM, TM, and SC were examined in ultrathin, sequential sections from different planes. The effect of pilocarpine (100 μM) on conventional outflow facility was measured by perfusion of enucleated mouse eyes. RESULTS The mouse TM contains a three-dimensional (3D) net of EL fibers connecting the inner wall of SC to the cornea anteriorly, the ciliary body (CB) internally and the choroid and CM posteriorly. The CM bifurcates near the posterior TM, extending outer tendons to the juxtacanalicular tissue and inner wall of SC and internal connections to the lamellated TM and CB. Ciliary muscle and lamellated TM cells stain with αSMA and are innervated by VAChT-containing nerve fibers, without TH, VIP, or nNOS. Pilocarpine doubled outflow facility. CONCLUSIONS Mouse eyes resemble primate eyes not only by their well developed SC and TM, but also by their 3D EL net tethering together the TM and SC inner wall and by the tendinous insertion of the CM into this net. The increase in outflow facility following cholinergic stimulation in mice, as in primates, supports using mice for studies of aqueous humor dynamics and glaucoma.
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Affiliation(s)
- Darryl R Overby
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Jacques Bertrand
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Martin Schicht
- Department of Anatomy II, University of Erlangen-Nürnberg, Germany
| | | | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States
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21
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Li G, Farsiu S, Chiu SJ, Gonzalez P, Lütjen-Drecoll E, Overby DR, Stamer WD. Pilocarpine-induced dilation of Schlemm's canal and prevention of lumen collapse at elevated intraocular pressures in living mice visualized by OCT. Invest Ophthalmol Vis Sci 2014; 55:3737-46. [PMID: 24595384 DOI: 10.1167/iovs.13-13700] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The goal was to assess effects of IOP and pilocarpine-induced ciliary muscle contraction on conventional outflow pathway tissues in living anesthetized mice. METHODS Intraocular pressure was controlled by intracameral cannulation of mouse eyes while imaging using spectral-domain optical coherence tomography (SD-OCT). Time-lapse sagittal SD-OCT sections through Schlemm's canal (SC) were acquired while changing IOP stepwise between 10 and 45 mm Hg. After topical application of 1% pilocarpine, the series of IOP steps and imaging were repeated. Effects of pilocarpine on IOP and outflow facility in living mice were verified by rebound tonometry and flow measurements at three different IOPs, respectively. In vivo OCT images were compared with eyes analyzed by standard histology. RESULTS In living mice imaged by SD-OCT, the lumen of SC progressively collapsed with increasing IOP, reaching near complete closure at 20 mm Hg. Schlemm's canal collapse was reversible, with the lumen opening within minutes after returning IOP from 45 to 10 mm Hg. Pilocarpine-induced ciliary muscle contraction changed SC lumen area by 131.6% ± 21.0% compared with untreated controls at 10 mm Hg, opened the trabecular meshwork, and prevented complete collapse of the SC lumen at higher pressures. Similar results were observed by standard histology. Pilocarpine increased outflow facility 4-fold (P = 0.02) and lowered IOP (16.46 ± 2.23 vs. 11.08 ± 2.28 mm Hg, P = 0.03). CONCLUSIONS Spectral-domain OCT was effective at visualizing changes in SC lumen in living mice. Results with pilocarpine are consistent with the concept that a primary role for the ciliary muscle is to prevent collapse of SC.
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Affiliation(s)
- Guorong Li
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | - Sina Farsiu
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Stephanie J Chiu
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Pedro Gonzalez
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | | | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
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Gong H, Yang CYC. Morphological and hydrodynamic correlations with increasing outflow facility by rho-kinase inhibitor Y-27632. J Ocul Pharmacol Ther 2014; 30:143-53. [PMID: 24460021 DOI: 10.1089/jop.2013.0192] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Abstract Rho-kinase inhibitors affect actomyosin cytoskeletal networks and have been shown to significantly increase outflow facility and lower intraocular pressure in various animal models and human eyes. This article summarizes common morphological changes in the trabecular meshwork induced by Rho-kinase inhibitors and specifically compares the morphological and hydrodynamic correlations with increased outflow facility by Rho-kinase inhibitor, Y-27632, in bovine, monkey, and human eyes under similar experimental conditions. Interspecies comparison has shown that morphological changes in the juxtacanalicular connective tissue (JCT) of these 3 species were different. However, these different morphological changes in the JCT, no matter if it's separation between the JCT and inner wall in bovine eyes, or separation between the JCT cells or between the JCT cells and their matrix in monkey eyes, or even no separation between the inner wall and the JCT but a more subtle expansion of the JCT in human eyes, appear to correlate with the increased percent change of outflow facility. More importantly, these different morphological changes all resulted in an increase in effective filtration area, which was positively correlated with increased outflow facility in all 3 species. These results suggest a link among changes in outflow facility, tissue architecture, and aqueous outflow pattern. Y-27632 increases outflow facility by redistributing aqueous outflow through a looser and larger area in the JCT.
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Affiliation(s)
- Haiyan Gong
- 1 Department of Ophthalmology, Boston University School of Medicine , Boston, Massachusetts
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23
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Inoue T, Tanihara H. Rho-associated kinase inhibitors: A novel glaucoma therapy. Prog Retin Eye Res 2013; 37:1-12. [DOI: 10.1016/j.preteyeres.2013.05.002] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 05/12/2013] [Accepted: 05/29/2013] [Indexed: 01/15/2023]
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Wang J, Liu X, Zhong Y. Rho/Rho-associated kinase pathway in glaucoma (Review). Int J Oncol 2013; 43:1357-67. [PMID: 24042317 DOI: 10.3892/ijo.2013.2100] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 08/21/2013] [Indexed: 11/06/2022] Open
Abstract
The Rho/ROCK pathway plays important roles in the modulation of the cytoskeletal integrity of cells, the synthesis of extracellular matrix components in the aqueous humor outflow tissue and the permeability of Schlemm's canal endothelial cells. The activation of the Rho/ROCK pathway results in trabecular meshwork (TM) contraction, and the inhibition of this pathway would provoke relaxation of TM with subsequent increase in outflow facility and, thereby, decrease intraocular pressure (IOP). ROCK inhibitors also serve as potent anti‑scarring agents via inhibition of transdifferentiation of tenon fibroblasts into myofibroblasts. Furthermore, the RhoA/ROCK pathway is involved in optic nerve neuroprotection. Inactivation of Rho/ROCK signaling increase ocular blood flow, improve retinal ganglion cell (RGC) survival and promote RGC axon regeneration. Considering the IOP modulation, potent bleb anti-scarring effect and neuroprotective properties of ROCK inhibitors, the Rho/ROCK pathway is an attractive target for anti-glaucoma therapy, and it may be used for human therapy in the near future.
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Affiliation(s)
- Jing Wang
- Department of Ophthalmology, Ruijin Hospital Affiliated Medical School, Shanghai Jiaotong University, Shanghai 200025, P.R. China
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25
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Iyer P, Maddala R, Pattabiraman PP, Rao PV. Connective tissue growth factor-mediated upregulation of neuromedin U expression in trabecular meshwork cells and its role in homeostasis of aqueous humor outflow. Invest Ophthalmol Vis Sci 2012; 53:4952-62. [PMID: 22761259 DOI: 10.1167/iovs.12-9681] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
PURPOSE Connective tissue growth factor (CTGF) is a matricellular protein presumed to be involved in the pathobiology of various fibrotic diseases, including glaucoma. We investigated the effects of Rho GTPase-dependent actin cytoskeletal integrity on CTGF expression and CTGF-induced changes in gene expression profile in human trabecular meshwork (HTM) cells. METHODS CTGF levels were quantified by immunoblotting and ELISA. CTGF-induced changes in gene expression, actin cytoskeleton, myosin light chain (MLC) phosphorylation, and extracellular matrix (ECM) proteins were evaluated in trabecular meshwork (TM) cells by cDNA microarray, q-PCR, fluorescence microscopy, and immunoblot analyses. The effects of neuromedin U (NMU) on aqueous humor (AH) outflow were determined in enucleated porcine eyes. RESULTS Expression of a constitutively active form of RhoA (RhoAV14), activation of Rho GTPase by bacterial toxin, or inhibition of Rho kinase by Y-27632 in HTM cells led to significant but contrasting changes in CTGF protein levels that were detectable in cell lysates and cell culture medium. Stimulation of HTM cells with CTGF for 24 hours induced actin stress fiber formation, and increased MLC phosphorylation, fibronectin, and laminin levels, and NMU expression. NMU independently induced actin stress fibers and MLC phosphorylation in TM cells, and decreased AH outflow facility in perfused porcine eyes. CONCLUSIONS These data revealed that CTGF influences ECM synthesis, actin cytoskeletal dynamics, and contractile properties in TM cells, and that the expression of CTGF is regulated closely by Rho GTPase. Moreover, NMU, whose expression is induced in response to CTGF, partially mimics the effects of CTGF on actomyosin organization in TM cells, and decreases AH outflow facility, revealing a potentially important role for this neuropeptide in the homeostasis of AH drainage.
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Affiliation(s)
- Padma Iyer
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC 27710, USA
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Suzuki M, Seki G, Yamada H, Horita S, Fujita T. Functional Roles of Electrogenic Sodium Bicarbonate Cotransporter NBCe1 in Ocular Tissues. Open Ophthalmol J 2012; 6:36-41. [PMID: 22798968 PMCID: PMC3394102 DOI: 10.2174/1874364101206010036] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Revised: 05/22/2012] [Accepted: 05/24/2012] [Indexed: 12/04/2022] Open
Abstract
Electrogenic Na+-HCO3- cotransporter NBCe1 is expressed in several tissues such as kidney, eye, and brain, where it may mediate distinct biological processes. In particular, NBCe1 in renal proximal tubules is essential for the regulation of systemic acid/base balance. On the other hand, NBCe1 in eye may be indispensable for the maintenance of tissue homeostasis. Consistent with this view, homozygous mutations in NBCe1 cause severe proximal renal tubular acidosis associated with ocular abnormalities such as band keratopathy, glaucoma, and cataract. The widespread expression of NBCe1 in eye suggests that the inactivation of NBCe1 per se may be responsible for the occurrence of these ocular abnormalities. In this review, we discuss about physiological and pathological roles of NBCe1 in eye.
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Affiliation(s)
- Masashi Suzuki
- Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan
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Abstract
Muscarinic agonists act mainly via muscarinic M₃ cholinoceptors to cause contraction of the iris sphincter, ciliary muscle and trabecular meshwork as well as increase outflow facility of aqueous humour. In the iris dilator, the effect of muscarinic agonists is species dependent but is predominantly relaxation via muscarinic M₃ receptors. In the conjunctiva, muscarinic agonists stimulate goblet cell secretion which contributes to the protective tear film. Muscarinic M₂ and M₃ receptors appear mainly involved. In the lens muscarinic agonists act via muscarinic M₁ receptors to produce depolarization and increase [Ca(2+)](i). All five subtypes of muscarinic receptor are present in the retina. In the developing retina, acetylcholine appears to limit purinergic stimulation of retinal development and decrease cell proliferation. In the adult retina acetylcholine and other muscarinic agonists may have complex effects, for example, enhancing light-evoked neuronal firing in transient ON retinal ganglion cells and inhibiting firing in OFF retinal ganglion cells. In the lacrimal gland, muscarinic agonists activate M₃ receptors on secretory globular acinar cells to stimulate tear secretion and also cause contraction of myoepithelial cells. In Sjögren's syndrome, antibodies to the muscarinic M₃ receptor disrupt normal gland function leading to xerophthalmia although the mechanism of action of the antibody is still not clear. Atropine and pirenzepine are useful in limiting the development of myopia in children probably by an action on muscarinic receptors in the sclera, although many other muscarinic receptor antagonists are not effective.
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Affiliation(s)
- Frederick Mitchelson
- Department of Pharmacology, University of Melbourne, Melbourne, VIC 3010, Australia.
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Yu WY, Sheridan C, Grierson I, Mason S, Kearns V, Lo ACY, Wong D. Progenitors for the corneal endothelium and trabecular meshwork: a potential source for personalized stem cell therapy in corneal endothelial diseases and glaucoma. J Biomed Biotechnol 2011; 2011:412743. [PMID: 22187525 PMCID: PMC3236530 DOI: 10.1155/2011/412743] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 09/08/2011] [Indexed: 12/15/2022] Open
Abstract
Several adult stem cell types have been found in different parts of the eye, including the corneal epithelium, conjunctiva, and retina. In addition to these, there have been accumulating evidence that some stem-like cells reside in the transition area between the peripheral corneal endothelium (CE) and the anterior nonfiltering portion of the trabecular meshwork (TM), which is known as the Schwalbe's Ring region. These stem/progenitor cells may supply new cells for the CE and TM. In fact, the CE and TM share certain similarities in terms of their embryonic origin and proliferative capacity in vivo. In this paper, we discuss the putative stem cell source which has the potential for replacement of lost and nonfunctional cells in CE diseases and glaucoma. The future development of personalized stem cell therapies for the CE and TM may reduce the requirement of corneal grafts and surgical treatments in glaucoma.
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Affiliation(s)
- Wing Yan Yu
- Eye Institute, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Carl Sheridan
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, University Clinical Departments Building, The Duncan Building, Daulby Street, Liverpool L69 3GA, UK
| | - Ian Grierson
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, University Clinical Departments Building, The Duncan Building, Daulby Street, Liverpool L69 3GA, UK
| | - Sharon Mason
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, University Clinical Departments Building, The Duncan Building, Daulby Street, Liverpool L69 3GA, UK
| | - Victoria Kearns
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, University Clinical Departments Building, The Duncan Building, Daulby Street, Liverpool L69 3GA, UK
| | - Amy Cheuk Yin Lo
- Eye Institute, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
- Research Center of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - David Wong
- Eye Institute, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
- Research Center of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
- St. Paul's Eye Unit, Royal Liverpool University Hospital, Prescot Street, Liverpool L7 8XP, UK
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Mains J, Tan LE, Wilson C, Urquhart A. A pharmacokinetic study of a combination of beta adrenoreceptor antagonists - in the isolated perfused ovine eye. Eur J Pharm Biopharm 2011; 80:393-401. [PMID: 22120686 DOI: 10.1016/j.ejpb.2011.11.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 10/17/2011] [Accepted: 11/10/2011] [Indexed: 11/27/2022]
Abstract
The treatment of posterior eye diseases, such as diabetic retinopathy and age-related macular degeneration, is of growing interest as the number of people affected by these conditions continues to rise. This study utilises the methods of cassette dosing and the perfused ovine eye model - to reduce animal usage and therefore animal time - to show that for a series of beta adrenoreceptor antagonists, lipophilicity is a key physicochemical property that governs drug distribution within the eye. Following intravitreal injection, lipophilic beta adrenoreceptor antagonists penetrate to the posterior eye, where they bind to the choroid and reside in the retina at greater concentrations than more hydrophilic beta adrenoreceptor antagonists, which preferentially penetrate to the anterior eye.
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Affiliation(s)
- Jenifer Mains
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Scotland, United Kingdom
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Mao W, Tovar-Vidales T, Yorio T, Wordinger RJ, Clark AF. Perfusion-cultured bovine anterior segments as an ex vivo model for studying glucocorticoid-induced ocular hypertension and glaucoma. Invest Ophthalmol Vis Sci 2011; 52:8068-75. [PMID: 21911581 DOI: 10.1167/iovs.11-8133] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine whether perfusion-cultured bovine anterior segments would be a suitable model for glaucoma research. METHODS Fresh bovine eyes were dissected and sealed on a custom-made acrylic dish with an O-ring. Perfusion medium was infused by a syringe pump at a constant infusion rate of 5 μL/min. After intraocular pressure (IOP) was stable, bovine eyes were perfused with medium containing either a vehicle control (0.1% ethanol [ETH]) or dexamethasone (DEX) for up to 7 days. IOP was recorded by a pressure transducer and a computerized system. Perfusion medium was collected for Western immunoblot analysis of myocilin (MYOC). RESULTS The morphology of the bovine trabecular meshwork after perfusion culture was similar to that of freshly dissected, nonperfused bovine eyes. Treatment with DEX elevated IOP in some bovine eyes, whereas others showed little change. The authors analyzed the data from 18 ETH-treated control eyes and defined 2.82 mm Hg as the threshold of ocular hypertension (OHT), which equals mean pressure change + 2× SD. Approximately 40% (12/29) of the bovine eyes were DEX responders, which is very close to the DEX-responsive rates observed in human and monkey eyes. Western blot data showed that DEX treatment induced the expression of the DEX-inducible gene MYOC only in the perfusion-cultured anterior segments with DEX-induced OHT. CONCLUSIONS OHT can be induced by DEX in perfusion-cultured bovine anterior segments. This is a fast, convenient, affordable, and reliable model for studying DEX-induced OHT and the mechanisms of trabecular outflow.
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Affiliation(s)
- Weiming Mao
- Department of Cell Biology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas 76107, USA.
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Russell-Randall KR, Dortch-Carnes J. Kappa opioid receptor localization and coupling to nitric oxide production in cells of the anterior chamber. Invest Ophthalmol Vis Sci 2011; 52:5233-9. [PMID: 21666232 DOI: 10.1167/iovs.10-6613] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The present study was designed to determine whether kappa opioid receptors (KORs) are localized to cells of the inflow and outflow pathways of the eye and if activation of these receptors has an effect on nitric oxide (NO) production, because these effects could play a role in KOR agonist-mediated reduction of IOP. METHODS Human nonpigmented ciliary epithelial (NPCE) and trabecular meshwork (HTM-3) cells were treated with spiradoline (SPR), a selective KOR agonist, or estradiol, for 24 hours. Some cells were pretreated with the selective KOR antagonist norbinaltorphimine (norBNI) or the nonselective NO synthase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME) for 30 minutes, followed by the addition of SPR. Immunofluorescent localization of KORs was determined in isolated rabbit iris-ciliary bodies (ICBs) and NPCE and HTM-3 cells. RESULTS Immunohistochemical data show the localization of KORs to the rabbit ICB and more specifically to the ciliary epithelial layer. KORs were also found on cell membranes of NPCE and HTM-3 cells. Treatment of both these cell types with spiradoline caused concentration-dependent increases in the release of NO. Spiradoline-induced release of NO from both cell types was inhibited by pretreatment with norBNI and L-NAME. CONCLUSIONS Results from this study show the presence of KORs on rabbit ICBs and also on NPCE and HTM cells. Activation of these KORs on both cell types resulted in KOR-mediated increases in NO production. These findings provide evidence that previously demonstrated KOR-mediated reduction in IOP could be caused, in part, by NO production in both the ciliary body and the trabecular meshwork.
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Affiliation(s)
- Karen R Russell-Randall
- Department of Pharmacology and Toxicology, Morehouse School of Medicine, Atlanta, Georgia 30310-1495, USA.
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Rosenthal R, Fromm M. Endothelin antagonism as an active principle for glaucoma therapy. Br J Pharmacol 2011; 162:806-16. [PMID: 21054341 DOI: 10.1111/j.1476-5381.2010.01103.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Endothelin, the most potent vasoactive peptide known to date, has been suggested to play a potential role in the pathogenesis of open-angle glaucoma. Open-angle glaucoma is the most common optic nerve head neuropathy and is associated with a loss of retinal ganglion cells and visual field damage. Although an increased intraocular pressure is a major risk factor for glaucomatous optic neuropathy, other factors such as a reduced ocular blood flow play an important role for appearance of the disease. Thus, treatment of glaucoma is focused on lowering of intraocular pressure and preventing the occurrence or progression of glaucomatous optic neuropathy. Endothelin participates in the regulation of intraocular pressure by an effect on trabecular outflow, the main route for aqueous humour outflow from the eye. Trabecular outflow is modulated by trabecular meshwork contractility which is affected by endothelin. In addition to the effects of endothelin in the anterior part of the eye, the vasoconstrictor causes a decrease in ocular blood flow followed by pathological changes in the retina and the optic nerve head which is assumed to contribute to the degeneration of retinal ganglion cells. In sum, inhibition of endothelin signalling leads to lowering of intraocular pressure and exerts neuroprotective effects. Thus, endothelin antagonism in the eye represents a promising approach for pharmacological treatment of glaucoma.
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Affiliation(s)
- Rita Rosenthal
- Institute of Clinical Physiology, Charité, Campus Benjamin Franklin, Freie Universität and Humboldt-Universität Berlin, Berlin, Germany
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Okamoto N, Ito Y, Nagai N, Murao T, Takiguchi Y, Kurimoto T, Mimura O. Preparation of ophthalmic formulations containing cilostazol as an anti-glaucoma agent and improvement in its permeability through the rabbit cornea. J Oleo Sci 2010; 59:423-30. [PMID: 20625234 DOI: 10.5650/jos.59.423] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To evaluate the pharmacological properties of cilostazol (CLZ), we examined its intraocular pressure (IOP) -lowering effect. CLZ is an inhibitor of Type III phosphodiesterase that increases intracellular cyclic AMP levels by restraining platelet aggregation, and has a potential protective effect against atherosclerosis. We attempted to apply it for use as an anti-glaucoma agent; however, the application of CLZ in the ophthalmic field is limited due to its poor water solubility. We attempted to enhance CLZ solubility using 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD). The solubility of CLZ increased with increasing HPbetaCD concentrations, and 0.05% CLZ was dissolved in 10% HPbetaCD. Moreover, fine particle suspension of 0.5% CLZ in 5% HPbetaCD (soluble CLZ: ca. 0.027%) were prepared using a Microfluidizer, an impact-type emulsifying comminution device. In an in vitro transcorneal penetration experiment through the rabbit cornea, the CLZ penetration rate was dependent on the CLZ content of the solutions and suspensions. When a 0.05% CLZ ophthalmic solution was instilled into a rabbit eye, the absorption rate constant for CLZ into an aqueous humor was 0.0059+/-0.001 min(-1), and the elimination rate constant was 0.048+/-0.024 min(-1). Also CLZ ophthalmic solutions and fine particle suspension were examined to for their ability to reduce enhanced intraocular pressure (IOP) of rabbits in a darkroom. The instillation of 0.05% CLZ ophthalmic solutions and 0.5% CLZ fine particle suspensions into rabbit eyes reduced the enhanced IOP. These results demonstrate that the instillation of CLZ ophthalmic solutions and fine particle suspensions may represent an effective anti-glaucoma formulation.
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Affiliation(s)
- Norio Okamoto
- Department of Ophthalmology, Hyogo Medical College, Nishinomiya, Japan
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VAV2 and VAV3 as candidate disease genes for spontaneous glaucoma in mice and humans. PLoS One 2010; 5:e9050. [PMID: 20140222 PMCID: PMC2816215 DOI: 10.1371/journal.pone.0009050] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Accepted: 01/18/2010] [Indexed: 12/22/2022] Open
Abstract
Background Glaucoma is a leading cause of blindness worldwide. Nonetheless, the mechanism of its pathogenesis has not been well-elucidated, particularly at the molecular level, because of insufficient availability of experimental genetic animal models. Methodology/Principal Findings Here we demonstrate that deficiency of Vav2 and Vav3, guanine nucleotides exchange factors for Rho guanosine triphosphatases, leads to an ocular phenotype similar to human glaucoma. Vav2/Vav3-deficient mice, and to a lesser degree Vav2-deficient mice, show early onset of iridocorneal angle changes and elevated intraocular pressure, with subsequent selective loss of retinal ganglion cells and optic nerve head cupping, which are the hallmarks of glaucoma. The expression of Vav2 and Vav3 tissues was demonstrated in the iridocorneal angle and retina in both mouse and human eyes. In addition, a genome-wide association study screening glaucoma susceptibility loci using single nucleotide polymorphisms analysis identified VAV2 and VAV3 as candidates for associated genes in Japanese open-angle glaucoma patients. Conclusions/Significance Vav2/Vav3-deficient mice should serve not only as a useful murine model of spontaneous glaucoma, but may also provide a valuable tool in understanding of the pathogenesis of glaucoma in humans, particularly the determinants of altered aqueous outflow and subsequent elevated intraocular pressure.
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Pattabiraman PP, Rao PV. Mechanistic basis of Rho GTPase-induced extracellular matrix synthesis in trabecular meshwork cells. Am J Physiol Cell Physiol 2009; 298:C749-63. [PMID: 19940066 DOI: 10.1152/ajpcell.00317.2009] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Elevated intraocular pressure arising from impaired aqueous humor drainage through the trabecular pathway is a major risk factor for glaucoma. To understand the molecular basis for Rho GTPase-mediated resistance to aqueous humor drainage, we investigated the possible interrelationship between actomyosin contractile properties and extracellular matrix (ECM) synthesis in human trabecular meshwork (TM) cells expressing a constitutively active form of RhoA (RhoAV14). TM cells expressing RhoAV14 exhibited significant increases in fibronectin, tenascin C, laminin, alpha-smooth muscle actin (alpha-SMA) levels, and matrix assembly in association with increased actin stress fibers and myosin light-chain phosphorylation. RhoAV14-induced changes in ECM synthesis and actin cytoskeletal reorganization were mimicked by lysophosphatidic acid and TGF-beta(2), known to increase resistance to aqueous humor outflow and activate Rho/Rho kinase signaling. RhoAV14, lysophosphatidic acid, and TGF-beta(2) stimulated significant increases in Erk1/2 phosphorylation, paralleled by profound increases in fibronectin, serum response factor (SRF), and alpha-SMA expression. Treatment of RhoA-activated TM cells with inhibitors of Rho kinase or Erk, on the other hand, decreased fibronectin and alpha-SMA levels. Although suppression of SRF expression (both endogenous and RhoA, TGF-beta(2)-stimulated) via the use of short hairpin RNA decreased alpha-SMA levels, fibronectin was unaffected. Conversely, fibronectin induced alpha-SMA expression in an SRF-dependent manner. Collectively, data on RhoA-induced changes in actomyosin contractile activity, ECM synthesis/assembly, and Erk activation, along with fibronectin-induced alpha-SMA expression in TM cells, reveal a potential molecular interplay between actomyosin cytoskeletal tension and ECM synthesis/assembly. This interaction could be significant for the homeostasis of aqueous humor drainage through the pressure-sensitive trabecular pathway.
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Dortch-Carnes J, Randall KR. Morphine-induced nitric oxide production in isolated, iris-ciliary bodies. Exp Eye Res 2009; 89:660-4. [PMID: 19555685 PMCID: PMC2757460 DOI: 10.1016/j.exer.2009.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 05/28/2009] [Accepted: 06/13/2009] [Indexed: 12/21/2022]
Abstract
Considerable evidence suggests that the nitric oxide (NO)/cGMP signaling pathway plays an integral role in opioid receptor-mediated responses in the cardiovascular and immune systems. Previous studies in our laboratory and others have shown that nitric oxide (NO) plays a role in morphine-induced reduction of intraocular pressure (IOP) and pupil diameter (PD) in the New Zealand white (NZW) rabbit. The present study is designed to determine the effect of morphine on NO production in the isolated, iris-ciliary body (ICB), site of aqueous humor production, as this effect could be associated with morphine-stimulated changes in aqueous humor dynamics and iris function. ICBs obtained from normal NZW rabbits were utilized in these experiments. In some experiments, ICB samples were treated with morphine (1, 10 and 100 microM) for 1 h and later examined for changes in NO levels using a NO detection kit. In other experiments, tissue samples were pretreated with naloxone (non-selective opioid receptor antagonist), L-NAME (non-selective NO-synthase inhibitor) or GSH (sulfhydryl reagent) for 30 min, followed by treatment with morphine (10 muM). Morphine caused a concentration-dependent increase in the release of NO from ICBs. Levels of NO detected in the incubation medium of ICB samples increased from 1.49 +/- 0.19 (control) to 8.81 +/- 2.20 microM/mg protein (morphine-treated; 100 microM). Morphine-stimulated release of NO was significantly inhibited in tissues pretreated with 10 microM naloxone, L-NAME, or GSH. Results obtained from this study suggest that morphine stimulates NO release from the ICB through a mechanism that involves activation of NO-releasing opioid receptors. These results support the in vivo effects of morphine demonstrated in previous studies.
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Affiliation(s)
- Juanita Dortch-Carnes
- Department of Pharmacology & Toxicology, Morehouse School of Medicine, 720 Westview Dr., Atlanta, GA, 30310-1495, USA. address:
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Wade NC, Grierson I, O'Reilly S, Hoare MJ, Cracknell KPB, Paraoan LI, Brotchie D, Clark AF. Cross-linked actin networks (CLANs) in bovine trabecular meshwork cells. Exp Eye Res 2009; 89:648-59. [PMID: 19540832 DOI: 10.1016/j.exer.2009.06.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 05/14/2009] [Accepted: 06/12/2009] [Indexed: 01/16/2023]
Abstract
A cytoskeletal feature of human trabecular meshwork (HTM) cells in vitro and ex vivo is the presence of cross-linked actin networks (CLANs) that are abundant in a proportion of TM cells exposed to dexamethasone (DEX) and also in cells from glaucoma patients. We wished to determine whether CLANs were present in the bovine trabecular meshwork (BTM), whether they were similarly induced by dexamethasone and whether the structures were comparable to CLANs in HTM cells. Cultures of HTM and BTM cells and ex vivo dissections of BTM tissue were stained with phalloidin (F-actin) and propidium iodide (nuclei) and imaged by confocal microscopy, thereafter being subjected to image analysis. Some CLAN-like structures were identified in ex vivo BTM tissue cultured with and without DEX. However we found that BTM cells in culture produced abundant CLANs when exposed to DEX; comparable to the best response from HTM cells. The CLANs were of similar dimensions and morphology to those found in human cells and they had a similar half life of 2 or 3 days following the removal of DEX. This work demonstrates that BTM cells provide a suitable model for future investigations of CLAN formation and function. BTM cultures are sufficiently hardy to thrive in low serum and serum-free conditions so we were able to show that aqueous humor stimulates CLAN formation in the target cells. Future research is directed at identifying the aqueous component(s) responsible for CLAN production.
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Affiliation(s)
- N C Wade
- Unit of Ophthalmology, University of Liverpool, Daulby Street, Liverpool L69 3GA, UK
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The trabecular meshwork outflow pathways: structural and functional aspects. Exp Eye Res 2009; 88:648-55. [PMID: 19239914 DOI: 10.1016/j.exer.2009.02.007] [Citation(s) in RCA: 322] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2009] [Accepted: 02/08/2009] [Indexed: 01/06/2023]
Abstract
The major drainage structures for aqueous humor (AH) are the conventional or trabecular outflow pathways, which are comprised of the trabecular meshwork (made up by the uveal and corneoscleral meshworks), the juxtacanalicular connective tissue (JCT), the endothelial lining of Schlemm's canal (SC), the collecting channels and the aqueous veins. The trabecular meshwork (TM) outflow pathways are critical in providing resistance to AH outflow and in generating intraocular pressure (IOP). Outflow resistance in the TM outflow pathways increases with age and primary open-angle glaucoma. Uveal and corneoscleral meshworks form connective tissue lamellae or beams that are covered by flat TM cells which rest on a basal lamina. TM cells in the JCT are surrounded by fibrillar elements of the extracellular matrix (ECM) to form a loose connective tissue. In contrast to the other parts of the TM, JCT cells and ECM fibrils do not form lamellae, but are arranged more irregularly. SC inner wall endothelial cells form giant vacuoles in response to AH flow, as well as intracellular and paracellular pores. In addition, minipores that are covered with a diaphragm are observed. There is considerable evidence that normal AH outflow resistance resides in the inner wall region of SC, which is formed by the JCT and SC inner wall endothelium. Modulation of TM cell tone by the action of their actomyosin system affects TM outflow resistance. In addition, the architecture of the TM outflow pathways and consequently outflow resistance appear to be modulated by contraction of ciliary muscle and scleral spur cells. The scleral spur contains axons that innervate scleral spur cells or that have the ultrastructural characteristics of mechanosensory nerve endings.
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Renieri G, Choritz L, Rosenthal R, Meissner S, Pfeiffer N, Thieme H. Effects of endothelin-1 on calcium-independent contraction of bovine trabecular meshwork. Graefes Arch Clin Exp Ophthalmol 2008; 246:1107-15. [PMID: 18401592 DOI: 10.1007/s00417-008-0817-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2008] [Revised: 03/02/2008] [Accepted: 03/03/2008] [Indexed: 10/22/2022] Open
Abstract
BACKGROUND Endothelin-1 (ET-1) is known to induce contraction of trabecular meshwork (TM) and is probably involved in the pathogenesis of glaucoma. Calcium (Ca(2+))-independent contraction has been shown in TM, and its inhibition may represent an interesting way of influencing outflow facility, and thus intraocular pressure (IOP). This study investigates the role of ET-1 and its receptors ET-A and ET-B (ET-AR and ET-BR) in TM Ca(2+)-independent contractility. METHODS Isometric tension measurements of bovine TM (BTM) strips were performed using a force-length transducer system. Intra- and extracellular Ca(2+) buffering was achieved by means of EGTA and BAPTA-AM. Under Ca(2+)-free conditions, ET-1-induced contractility of TM was assessed also in the presence of the specific inhibitors for ET-AR and ET-BR, BQ123 and BQ788 respectively. In order to clarify the intracellular mediators of Ca(2+)-independent contractility induced by ET-1, TM contraction was further measured in the presence of Y-27632, a selective inhibitor of Rho-associated kinases (ROCKs). The expression of ROCK1 and of its activating protein RhoA in BTM cells was investigated using western blot analysis. RESULTS ET-1 induced a significant contraction of native BTM after intra- and extracellular Ca(2+)-depletion (45% +/- 8% of the maximally inducible contraction). Both endothelin receptor inhibitors BQ123 and BQ788 significantly reduced TM Ca(2+)-independent contraction in response to ET-1 (8.4 +/- 3.3% and 20.3 +/- 4.8% respectively). In the presence of the ROCK inhibitor Y-27632, ET-1-induced contraction of TM under Ca(2+)-free conditions was almost completely abolished (4.3% +/- 1.7%, p < 0.001). A clear signal for RhoA at 24 kDa and ROCK1 at 160 kDa could be detected in lysates of native tissue and cultured BTM cells with western blot. CONCLUSIONS This study shows evidence that a significant portion of ET-1-induced contraction of TM is Ca(2+)-independent. In this contraction pathway, both ET-AR and ET-BR are involved with RhoA and its kinases as intracellular mediators. Ca(2+)-independent contraction of TM in response to ET-1 may represent a specific target to modulate IOP.
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Affiliation(s)
- Giulia Renieri
- Department of Ophthalmology, Johannes Gutenberg-Universität, Langenbeckstrasse 1, 55101, Mainz, Germany
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Oxidative stress and glaucoma: injury in the anterior segment of the eye. PROGRESS IN BRAIN RESEARCH 2008; 173:385-407. [PMID: 18929123 DOI: 10.1016/s0079-6123(08)01127-8] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The perturbation of the pro-oxidant/antioxidant balance can lead to increased oxidative damage, especially when the first line of antioxidant defense weakens with age. Chronic changes in the composition of factors present in aqueous or vitreous humor may induce alterations both in trabecular cells and in cells of the optic nerve head. Free radicals and reactive oxygen species are able to affect the cellularity of the human trabecular meshwork (HTM). These findings suggest that intraocular pressure increase, which characterizes most glaucomas, is related to oxidative and degenerative processes affecting the HTM and, more specifically, its endothelial cells. This supports the theory that glaucomatous damage is the pathophysiological consequence of oxidative stress. Glaucomatous subjects might have a genetic predisposition, rendering them more susceptible to reactive oxygen species-induced damage. It is likely that specific genetic factors contribute to both the elevation of IOP and susceptibility of the optic nerve/retinal ganglion cells (RGCs) to degeneration. Thus, oxidative stress plays a fundamental role during the arising of glaucoma-associated lesions, first in the HTM and then, when the balance between nitric oxide and endothelins is broken, in neuronal cell. Vascular damage and hypoxia, often associated with glaucoma, lead to apoptosis of RGCs and may also contribute to the induction of oxidative damage to the HTM. On the whole, these findings support the hypothesis that oxidative damage is an important step in the pathogenesis of primary open-angle glaucoma and might be a relevant target for both prevention and therapy.
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Toris CB, Camras CB. Chapter 8 Aqueous Humor Dynamics II. CURRENT TOPICS IN MEMBRANES 2008. [DOI: 10.1016/s1063-5823(08)00408-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Rosenthal R, Choritz L, Zorn R, Münzer G, Fromm M, Pfeiffer N, Thieme H. Endothelin receptor B in trabecular meshwork. Exp Eye Res 2007; 85:482-91. [PMID: 17669399 DOI: 10.1016/j.exer.2007.06.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Revised: 06/12/2007] [Accepted: 06/19/2007] [Indexed: 01/08/2023]
Abstract
Endothelin-1 (ET-1), the most potent vasoconstrictor known to date, seems to be involved in the pathogenesis of primary open angle glaucoma. ET-1 was found in different tissues of the eye and in high concentrations in the aqueous humour. The effects of ET-1 are mediated by two receptors, ET-A receptor (ET-AR) and ET-B receptor (ET-BR), which are both expressed in bovine trabecular meshwork (TM). ET-1 induced contraction of TM predominantly by activation of ET-AR. This study analyzes the role of ET-BR in TM function and investigates the synthesis of ET-1 by human TM (HTM) cells. The effect of IRL-1620, a specific ET-BR agonist, on contractility of bovine TM (BTM) was investigated with a force length transducer system. The effect of this agonist on intracellular free Ca(2+) [Ca(2+)](i) was examined using the Ca(2+)-sensitive dye fura-2AM. The expression of the ET-AR and ET-BR was investigated in cultured HTM cells using Western blot and PCR methods. With PCR methods the expression of prepro-endothelin-1 (ppET-1) and isoforms of endothelin-1 converting enzyme (ECE-1) in cultured HTM cells was analyzed. Activation of ET-BR by IRL-1620 (5 x 10(-7)M) results in contraction of native BTM (41% of the carbachol value) and also in a transient increase in [Ca(2+)](i) in cultured BTM and HTM cells (365 and 273% of the basal level, respectively). IRL-1620 also induced contraction in native BTM under intra- and extracellularly Ca(2+)-free conditions. A clear signal for ET-AR at 40 kDa and ET-BR at 35 kDa could be detected in membrane lysates of cultured HTM cells. PCR analysis further confirmed the existence of ET-AR and ET-BR in these cells. Furthermore, RT-PCR revealed that neither ppET-1 nor one of the ECE-1 isoforms was expressed in cultured HTM cells. This study presents evidence for the expression of a functional ET-BR in bovine and human TM. Currently, there is no evidence for ET-1 synthesis in HTM cells. Further investigations are necessary to clarify the physiological function of ET-BR in TM and the source of ET-1 at this tissue.
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Affiliation(s)
- Rita Rosenthal
- Institut für Klinische Physiologie, Charité, Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany.
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Shimazaki A, Kirihara T, Rao PV, Tajima H, Matsugi T, Epstein DL. Effects of the new ethacrynic acid oxime derivative SA12590 on intraocular pressure in cats and monkeys. Biol Pharm Bull 2007; 30:1445-9. [PMID: 17666801 DOI: 10.1248/bpb.30.1445] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To evaluate the pharmacological characteristics of SA12590, a new oxime-derivative of the ethacrynic acid (ECA) derivative SA9000, we examined both its ocular hypotensive effects (in ocular normotensive cats and cynomolgus monkeys) and its potential corneal toxicity (in rats). A 50 microl topical administration of 3% SA12590 significantly reduced intraocular pressure (IOP) (by 3.5 mmHg) in anesthetized cats (p<0.05). Twenty-four hours after 3 drops (5-min intervals) of 20 microl 3% SA12590, IOP was reduced by 8 mmHg (p<0.05, n=4) in conscious monkeys without evidence of corneal toxicity. Three days' daily single 20 microl dosing with 3% SA12590 reduced IOP by 4 mmHg (p<0.01, n=3) at 72 h after the first administration in conscious monkeys. The toxicity of topically administered 20 microl 3% SA9000 or SA12590 (3 drops with 5-min intervals) on rat corneal epithelium was assessed using a photo-slit lamp. In this study, 3% SA12590, unlike 3% SA9000, exhibited no corneal toxicity. In a glutathione assay for sulfhydryl (SH) reactivity, SA12590, unlike SA9000, displayed no in vitro SH reactivity. Thus, oxime-modification may both improve efficacy towards IOP upon topical administration and improve the safety profile, probably by enhancing corneal penetration and minimizing SH reactivity-related toxicity. These findings indicate that SA12590 has potential as a new ocular hypotensive drug.
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Affiliation(s)
- Atsushi Shimazaki
- Research and Development Center, Santen Pharmaceutical Co. Ltd., 8916-16 Takayama, Ikoma 630-0101, Japan.
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Tane N, Dhar S, Roy S, Pinheiro A, Ohira A, Roy S. Effect of excess synthesis of extracellular matrix components by trabecular meshwork cells: possible consequence on aqueous outflow. Exp Eye Res 2007; 84:832-42. [PMID: 17350618 DOI: 10.1016/j.exer.2007.01.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Revised: 11/10/2006] [Accepted: 01/03/2007] [Indexed: 10/23/2022]
Abstract
The extracellular matrix (ECM) of the trabecular meshwork (TM) is an important determinant of its functional properties. This study was performed to investigate whether overexpression of ECM components, laminin (LM) and collagen type IV (Col) by TM cells may play a role in the development of outflow resistance. To determine the effect of excess LM and Col expression on cell monolayer permeability, an in vitro cell culture model was used in which overexpression of the two ECM components, LM and Col, was induced by high glucose (HG) (30 mM) or 0.1 microM dexamethasone (D) in bovine and human trabecular meshwork (BTM and HTM) cells. Western blot analysis and immunofluorescence staining confirmed increased LM and Col synthesis in cells exposed to HG or D. Increased level of LM and Col protein resulted in reduced cell monolayer permeability. Transfection with antisense oligos (AS-oligos) targeted against LM or Col inhibited HG- or D-induced LM and Col gene overexpression in TM cells with concomitant increase in permeability. The AS-oligo strategy was effective in reducing LM or Col level in the TM cells in all conditions tested in this study. These findings suggest that increased LM and Col deposition in the outflow pathway may cause resistance to aqueous outflow and contribute to the development of primary open angle glaucoma (POAG).
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Affiliation(s)
- Nobuhiro Tane
- Department of Medicine, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118, USA.
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Fautsch MP, Johnson DH. Aqueous humor outflow: what do we know? Where will it lead us? Invest Ophthalmol Vis Sci 2006; 47:4181-7. [PMID: 17003404 PMCID: PMC2092444 DOI: 10.1167/iovs.06-0830] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Michael P Fautsch
- Department of Ophthalmology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
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Thieme H, Steinhausen K, Ottlecz A, Lambrou GN, Strauss O, Wiederholt M, Rosenthal R. Effects of Unoprostone and Endothelin 1 on L-Type Channel Currents in Human Trabecular Meshwork Cells. Ophthalmic Res 2005; 37:293-300. [PMID: 16118512 DOI: 10.1159/000087724] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2004] [Accepted: 02/24/2005] [Indexed: 11/19/2022]
Abstract
BACKGROUND The trabecular meshwork (TM) is a smooth muscle-like tissue with contractile properties and by this mechanisms involved in the regulation of aqueous humor outflow. Isopropyl unoprostone (Rescula, Novartis Ophthalmics), a synthetic docosanoid, reduces intraocular pressure in glaucoma patients and normal subjects. In isolated TM strips, unoprostone reduces TM contractility in the presence of endothelin 1 (ET-1). However, the signal transduction pathway of unoprostone still remains unclear. Since L-type channel currents are known to influence the contractility of TM, we examined the effects of unoprostone and ET-1 on L-type channel currents of TM cells. METHODS The effects of unoprostone, ET-1 and the tyrosine kinase inhibitor herbimycin A on L-type channel currents of cultured human TM cells were investigated using the perforated patch configuration of the patch-clamp technique. RESULTS Application of ET-1 had no effect on L-type channel currents. Unoprostone led to a dose-dependent reduction of control currents. The effect of unoprostone is independent of ET-1. After preincubation of cells with herbimycin A, unoprostone had no effect on the L-type channel current amplitude. Human TM cells preincubated with herbimycin A showed a reduced current density compared with control cells. Both substances, unoprostone and herbimycin A, increased the inactivation time constant of L-type channel currents. CONCLUSION We conclude that unoprostone reduces the activity of L-type Ca2+ channels. This effect seems to be independent of ET-1. The signal transduction pathway seems to be mediated by tyrosine kinases.
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Affiliation(s)
- Hagen Thieme
- Augenklinik und Hochschulambulanz, Berlin, Germany
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Choritz L, Rosenthal R, Fromm M, Foerster MH, Thieme H. Pharmacological and functional characterization of endothelin receptors in bovine trabecular meshwork and ciliary muscle. Ophthalmic Res 2005; 37:179-87. [PMID: 15976515 DOI: 10.1159/000086471] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2004] [Accepted: 01/03/2005] [Indexed: 11/19/2022]
Abstract
To clarify the potential role of endothelin-1 (ET-1) in the pathogenesis of glaucoma, the endothelin receptors expressed in bovine trabecular meshwork (TM) and ciliary muscle (CM) were identified. TM and CM strips were subjected to ET-1 as well as to specific endothelin receptor antagonists. In both tissues BQ123, a specific ET-A receptor antagonist, substantially inhibited ET-1-induced contraction. BQ788, a specific ET-B receptor antagonist, showed only moderate effects. Both ET receptor types were detected in bovine TM and CM using Western blot analysis. ET-1 produced an increase in intracellular calcium in cultured TM cells. This effect was inhibited by BQ123, but not by BQ788. Thus, although both receptors are present, the ET-A receptor appears to play the predominant role in mediating contraction in both the TM and CM, while the ET-B receptor seems to contribute little to the overall ET-1 effect.
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Affiliation(s)
- Lars Choritz
- Institut für Klinische Physiologie, Charité, Universitätmedizin Berlin, Berlin, Deutschland
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Soto D, Pintor J, Peral A, Gual A, Gasull X. Effects of dinucleoside polyphosphates on trabecular meshwork cells and aqueous humor outflow facility. J Pharmacol Exp Ther 2005; 314:1042-51. [PMID: 15947035 DOI: 10.1124/jpet.105.085274] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The most important risk factor for the development of glaucoma is elevated intraocular pressure (IOP). Hypotensive drugs decrease IOP, preventing optic nerve damage and further vision loss. The balance between aqueous humor (AH) production and drainage determines IOP, and problems in AH outflow pathways are associated with open-angle glaucoma development. Previous studies have shown the presence of diadenosine tetraphosphate (Ap(4)A) and pentaphosphate (Ap(5)A) in the AH. Topic application of Ap(4)A to the cornea decreased IOP, whereas Ap(5)A increased it. Because dinucleoside polyphosphates stimulate P2Y purinergic receptors, we studied their presence in trabecular meshwork (TM) cells. Additionally, the effects of diadenosine polyphosphates (Ap(n)As; n = 3-5) and Up(4)U (P(1),P(4)-(diuridine 5')-tetraphosphate; INS365) in outflow facility were tested. P2Y(1), P2Y(2), and P2Y(4) receptors were detected in TM cells by Western blot and immunocytochemistry. In TM cells, Ap(3)A, Ap(4)A, and Ap(5)A induced discrete intracellular calcium concentration ([Ca(2+)](i)) mobilizations compared with higher and more sustained [Ca(2+)](i) mobilizations after Up(4)U application. In bovine ocular anterior segments perfused at constant pressure, 1 microM Ap(3)A or Ap(4)A increased outflow facility, whereas Up(4)U or Ap(5)A did not modify it. 2-MeSADP, a selective P2Y(1) agonist, induced outflow facility increases similar to those obtained after Ap(3)A and Ap(4)A, and these were prevented by addition of the selective P2Y(1) receptor antagonist MRS-2179 (2'-deoxy-N(6)-methyladenosine-3',5'-diphosphate). Our results demonstrate that the hypotensive effect of Ap(4)A and other dinucleotides is mediated, at least in part, by increasing trabecular outflow facility through activation of P2Y(1) receptors. The latter would seem to be an interesting target in the development of antiglaucomatous drugs to selectively increase AH outflow.
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Affiliation(s)
- David Soto
- Laboratori de Neurofisiologia, Facultat de Medicina-Institut d'Investigacions Biomèdiques August Pi i Sunyer, Universitat de Barcelona, Spain
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Abstract
The porcine eye serves as a model to study various functions of the aqueous outflow system. To compare these data with the primate eye, a detailed investigation of the distribution of contractile properties and of the innervation of the outflow region was conducted in the porcine eye. In all quadrants of the anterior eye segment, elastic fibres connected the ciliary muscle (CM) with the well-developed scleral spur (ScS) and also partly with the corneoscleral trabecular meshwork (TM) and the loops of the collecting outflow channels. Immunohistochemistry with antibodies against smooth muscle alpha-actin revealed intense staining of the CM and some myofibroblasts in the ScS and outer TM. In addition to a few cholinergic and aminergic nerve fibres in the outflow region, numerous substance P- and calcitonin-gene related peptide-positive nerve fibres and nerve endings were found near the outflow loops of the porcine TM. Although the porcine CM serves rather as a tensor choroideae muscle than as a muscle for accommodation, the innervation and morphology of the collecting outflow channel loops and of the expanded TM between the ScS and the cornea showed close similarities to the primate eye.
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Affiliation(s)
- Christian Albrecht May
- Department of Anatomy II, Friedrich Alexander University Erlangen-Nuernberg, Erlangen, Germany
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