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Redmon SN, Lakk M, Tseng YT, Rudzitis CN, Searle JE, Ahmed F, Unser A, Borrás T, Torrejon K, Krizaj D. TRPV4 subserves physiological and pathological elevations in intraocular pressure. RESEARCH SQUARE 2024:rs.3.rs-4714050. [PMID: 39041037 PMCID: PMC11261973 DOI: 10.21203/rs.3.rs-4714050/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Ocular hypertension (OHT) caused by mechanical stress and chronic glucocorticoid exposure reduces the hydraulic permeability of the conventional outflow pathway. It increases the risk for irreversible vision loss, yet healthy individuals experience nightly intraocular pressure (IOP) elevations without adverse lifetime effects. It is not known which pressure sensors regulate physiological vs. pathological OHT nor how they impact the permeability of the principal drainage pathway through the trabecular meshwork (TM). We report that OHT induced by the circadian rhythm, occlusion of the iridocorneal angle and glucocorticoids requires activation of TRPV4, a stretch-activated cation channel. Wild-type mice responded to nocturnal topical administration of the agonist GSK1016790A with IOP lowering, while intracameral injection of the agonist elevated diurnal IOP. Microinjection of TRPV4 antagonists HC067047 and GSK2193874 lowered IOP during the nocturnal OHT phase and in hypertensive eyes treated with steroids or injection of polystyrene microbeads. Conventional outflow-specific Trpv4 knockdown induced partial IOP lowering in mice with occluded iridocorneal angle and protected retinal neurons from pressure injury. Indicating a central role for TRPV4-dependent mechanosensing in trabecular outflow, HC067047 doubled the outflow facility in TM-populated steroid-treated 3D nanoscaffolds. Tonic TRPV4 signaling thus represents a fundamental property of TM biology as a driver of increased in vitro and in vivo outflow resistance. The TRPV4-dependence of OHT under conditions that mimic primary and secondary glaucomas could be explored as a novel target for glaucoma treatments.
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Li G, van Batenburg‐Sherwood J, Safa BN, Fraticelli Guzmán NS, Wilson A, Bahrani Fard MR, Choy K, de Ieso ML, Cui JS, Feola AJ, Weisz T, Kuhn M, Bowes Rickman C, Farsiu S, Ethier CR, Stamer WD. Aging and intraocular pressure homeostasis in mice. Aging Cell 2024; 23:e14160. [PMID: 38566432 PMCID: PMC11258442 DOI: 10.1111/acel.14160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 03/09/2024] [Accepted: 03/14/2024] [Indexed: 04/04/2024] Open
Abstract
Age and elevated intraocular pressure (IOP) are the two primary risk factors for glaucoma, an optic neuropathy that is the leading cause of irreversible blindness. In most people, IOP is tightly regulated over a lifetime by the conventional outflow tissues. However, the mechanistic contributions of age to conventional outflow dysregulation, elevated IOP and glaucoma are unknown. To address this gap in knowledge, we studied how age affects the morphology, biomechanical properties and function of conventional outflow tissues in C57BL/6 mice, which have an outflow system similar to humans. As reported in humans, we observed that IOP in mice was maintained within a tight range over their lifespan. Remarkably, despite a constellation of age-related changes to the conventional outflow tissues that would be expected to hinder aqueous drainage and impair homeostatic function (decreased cellularity, increased pigment accumulation, increased cellular senescence and increased stiffness), outflow facility, a measure of conventional outflow tissue fluid conductivity, was stable with age. We conclude that the murine conventional outflow system has significant functional reserve in healthy eyes. However, these age-related changes, when combined with other underlying factors, such as genetic susceptibility, are expected to increase risk for ocular hypertension and glaucoma.
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Affiliation(s)
- Guorong Li
- Department of OphthalmologyDuke UniversityDurhamNorth CarolinaUSA
| | | | - Babak N. Safa
- Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGeorgiaUSA
| | - Nina Sara Fraticelli Guzmán
- Department of OphthalmologyEmory UniversityAtlantaGeorgiaUSA
- George W. Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlantaGeorgiaUSA
| | - Andrea Wilson
- Department of OphthalmologyDuke UniversityDurhamNorth CarolinaUSA
| | - Mohammad Reza Bahrani Fard
- Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGeorgiaUSA
| | - Kevin Choy
- Department of Biomedical EngineeringDuke UniversityDurhamNorth CarolinaUSA
| | | | - J. Serena Cui
- Department of OphthalmologyDuke UniversityDurhamNorth CarolinaUSA
| | - Andrew J. Feola
- Department of OphthalmologyEmory UniversityAtlantaGeorgiaUSA
- Department of Biomedical EngineeringDuke UniversityDurhamNorth CarolinaUSA
- Center for Visual and Neurocognitive RehabilitationAtlanta Virginia Medical CenterDecaturGeorgiaUSA
| | - Tara Weisz
- Department of OphthalmologyDuke UniversityDurhamNorth CarolinaUSA
| | - Megan Kuhn
- Department of OphthalmologyDuke UniversityDurhamNorth CarolinaUSA
| | | | - Sina Farsiu
- Department of OphthalmologyDuke UniversityDurhamNorth CarolinaUSA
- Department of Biomedical EngineeringDuke UniversityDurhamNorth CarolinaUSA
| | - C. Ross Ethier
- Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of Technology and Emory UniversityAtlantaGeorgiaUSA
- Department of OphthalmologyEmory UniversityAtlantaGeorgiaUSA
| | - W. Daniel Stamer
- Department of OphthalmologyDuke UniversityDurhamNorth CarolinaUSA
- Department of Biomedical EngineeringDuke UniversityDurhamNorth CarolinaUSA
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Overby DR, Ethier CR, Miao C, Kelly RA, Reina-Torres E, Stamer WD. The Factors Affecting the Stability of IOP Homeostasis. Invest Ophthalmol Vis Sci 2024; 65:4. [PMID: 38833261 PMCID: PMC11157970 DOI: 10.1167/iovs.65.6.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 04/30/2024] [Indexed: 06/06/2024] Open
Abstract
Purpose Shear-induced nitric oxide (NO) production by Schlemm's canal (SC) endothelial cells provides a fast, IOP-sensitive feedback signal that normally contributes to IOP homeostasis. Our goal was to analyze the response of this homeostatic system under constant flow perfusion (as occurs in vivo) vs. constant pressure perfusion (as typical for laboratory perfusions). Methods A mathematical model of aqueous humor dynamics, including shear-mediated NO signaling, was formulated and analyzed for stability. The model includes Goldmann's equation, accounting for proximal and distal outflow resistance, and describes how elevated IOP causes narrowing of SC lumen that increases the shear stress on SC cells. Elevated shear stress stimulates NO production, which acts to reduce outflow resistance and relax trabecular meshwork cells to decrease trabecular meshwork stiffness, affecting the SC luminal caliber. Results During constant flow perfusion, the outflow system is typically stable, returning to baseline IOP after a perturbation. In contrast, during constant pressure perfusion, the outflow system can become unstable and exhibit a time-dependent change in outflow resistance that diverges from baseline. Conclusions The stability of shear mediated IOP homeostasis is predicted to differ critically between constant flow vs. constant pressure perfusion. Because outflow facility is typically measured at a constant pressure in the laboratory, this instability may contribute to the characteristic time-dependent increase in outflow facility, known as washout, observed in many nonhuman species. Studies of IOP homeostasis should consider how the outflow system may respond differently under constant pressure vs. constant flow perfusion.
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Affiliation(s)
- Darryl R. Overby
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - C. Ross Ethier
- Wallace H. Coulter Department of Biomedical Engineering at Georgia Institute of Technology & Emory University School of Medicine, Atlanta, Georgia, United States
| | - Changxu Miao
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Ruth A. Kelly
- Department of Ophthalmology, Duke University Medical School, Durham, North Carolina, United States
| | - Ester Reina-Torres
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - W. Daniel Stamer
- Department of Ophthalmology, Duke University Medical School, Durham, North Carolina, United States
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Li H, Kuhn M, Kelly RA, Singh A, Palanivel KK, Salama I, De Ieso ML, Stamer WD, Ganapathy PS, Herberg S. Targeting YAP/TAZ mechanosignaling to ameliorate stiffness-induced Schlemm's canal cell pathobiology. Am J Physiol Cell Physiol 2024; 326:C513-C528. [PMID: 38105758 PMCID: PMC11192480 DOI: 10.1152/ajpcell.00438.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/12/2023] [Accepted: 12/12/2023] [Indexed: 12/19/2023]
Abstract
Pathological alterations in the biomechanical properties of the Schlemm's canal (SC) inner wall endothelium and its immediate vicinity are strongly associated with ocular hypertension in glaucoma due to decreased outflow facility. Specifically, the underlying trabecular meshwork is substantially stiffer in glaucomatous eyes compared with that from normal eyes. This raises the possibility of a critical involvement of mechanotransduction processes in driving SC cell dysfunction. Yes-associated protein (YAP) has emerged as a key contributor to glaucoma pathogenesis. However, the molecular underpinnings of SC cell mechanosignaling via YAP and transcriptional coactivator with PDZ-binding motif (TAZ) in response to glaucomatous extracellular matrix (ECM) stiffening are not well understood. Using a novel biopolymer hydrogel that facilitates dynamic and reversible stiffness tuning, we investigated how ECM stiffening modulates YAP/TAZ activity in primary human SC cells, and whether disruption of YAP/TAZ mechanosignaling attenuates SC cell pathobiology and increases ex vivo outflow facility. We demonstrated that ECM stiffening drives pathologic YAP/TAZ activation and cytoskeletal reorganization in SC cells, which was fully reversible by matrix softening in a distinct time-dependent manner. Furthermore, we showed that pharmacologic or genetic disruption of YAP/TAZ mechanosignaling abrogates stiffness-induced SC cell dysfunction involving altered cytoskeletal and ECM remodeling. Finally, we found that perfusion of the clinically used, small molecule YAP/TAZ inhibitor verteporfin (without light activation) increases ex vivo outflow facility in normal mouse eyes. Collectively, our data provide new evidence for a pathologic role of aberrant YAP/TAZ mechanosignaling in SC cell dysfunction and suggest that YAP/TAZ inhibition has therapeutic value for treating ocular hypertension in glaucoma.NEW & NOTEWORTHY Pathologically altered biomechanical properties of the Schlemm's canal (SC) inner wall microenvironment were recently validated as the cause for increased outflow resistance in ocular hypertensive glaucoma. However, the involvement of specific mechanotransduction pathways in these disease processes is largely unclear. Here, we demonstrate that Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) are central regulators of glaucoma-like SC cell dysfunction in response to extracellular matrix stiffening and that targeted disruption of YAP/TAZ mechanosignaling attenuates SC cell pathobiology and enhances outflow function.
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Affiliation(s)
- Haiyan Li
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, United States
- BioInspired Institute, Syracuse University, Syracuse, New York, United States
| | - Megan Kuhn
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, North Carolina, United States
| | - Ruth A Kelly
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, North Carolina, United States
| | - Ayushi Singh
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, United States
- BioInspired Institute, Syracuse University, Syracuse, New York, United States
| | - Kavipriya Kovai Palanivel
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
| | - Izzy Salama
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
| | - Michael L De Ieso
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, North Carolina, United States
| | - W Daniel Stamer
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, North Carolina, United States
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Preethi S Ganapathy
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
- BioInspired Institute, Syracuse University, Syracuse, New York, United States
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York, United States
| | - Samuel Herberg
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, United States
- BioInspired Institute, Syracuse University, Syracuse, New York, United States
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, United States
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States
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Jonas JB, Jonas RA, Jonas SB, Panda-Jonas S. Bruch's membrane and Brücke's muscle in the pars plana region. Acta Ophthalmol 2024; 102:e53-e59. [PMID: 38185862 DOI: 10.1111/aos.15678] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/13/2023] [Indexed: 01/09/2024]
Abstract
PURPOSE To examine Bruch's membrane (BM) in association with the longitudinal part of the ciliary muscle (LPCM) in the pars plana region. METHODS Using light microscopy, we histomorphometrically assessed BM and the LPCM in the pars plana region. RESULTS The histomorphometric study included 51 eyes (51 patients; mean age: 60.8 ± 15.0 years; axial length: 26.0 ± 3.3 mm; range: 21.0-36.0 mm). The LPCM (total length: 4.60 ± 1.10 mm) ended 1.15 ± 0.56 mm anterior to the ora serrata. Within the pars plana region, the LPCM (length: 2.58 ± 0.98 mm) had direct contact with BM for 1.95 ± 0.99 mm (71.1 ± 18.4% of the BM undersurface), while a capillary layer was interposed between the BM and the LPCM for 0.70 ± 0.40 mm (29.0 ± 18.4%). In the pars plana region free of LPCM close to the ora serrata, the percentage of BM covered by the capillary layer was higher than in the pars plana region containing the LPCM (63.0 ± 42.1% vs. 29.0 ± 18.4%; p < 0.001). At the LPCM end, BM was in direct contact with a collagenous tissue from the LPCM and was focally thickened as compared to BM with an underlying capillary layer (9.5 ± 5.3 μm vs. 4.3 ± 1.2 μm; p < 0.001). CONCLUSIONS The direct contact of BM with the LPCM in the pars plana in association with focal BM thickening at the LPCM end suggests an insertion of LPCM on the BM. Taking into account the biomechanical strength of BM, it may imply a functional unit of the LPCM with BM in the process of accommodation with a secondary movement of the posterior BM and tertiary thickening of the subfoveal choroidal space.
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Affiliation(s)
- Jost B Jonas
- Department of Ophthalmology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland
- Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Rahul A Jonas
- Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Shefali B Jonas
- Privatpraxis Prof Jonas und Dr Panda-Jonas, Heidelberg, Germany
| | - Songhomitra Panda-Jonas
- Department of Ophthalmology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland
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6
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Li G, van Batenburg-Sherwood J, Safa BN, Fraticelli Guzmán NS, Wilson A, Bahrani Fard MR, Choy K, De Ieso ML, Cui JS, Feola AJ, Weisz T, Kuhn M, Rickman CB, Farsiu S, Ethier CR, Stamer WD. Aging and intraocular pressure homeostasis in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.17.562768. [PMID: 38106150 PMCID: PMC10723259 DOI: 10.1101/2023.10.17.562768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Age and elevated intraocular pressure (IOP) are the two primary risk factors for glaucoma, an optic neuropathy that is the leading cause of irreversible blindness. In most people, IOP is tightly regulated over a lifetime by the conventional outflow tissues. However, the mechanistic contributions of age to conventional outflow dysregulation, elevated IOP and glaucoma are unknown. To address this gap in knowledge, we studied how age affects the morphology, biomechanical properties and function of conventional outflow tissues in C57BL/6 mice, which have an outflow system similar to humans. As reported in humans, we observed that IOP in mice was maintained within a tight range over their lifespan. Remarkably, despite a constellation of age-related changes to the conventional outflow tissues that would be expected to hinder aqueous drainage and impair homeostatic function (decreased cellularity, increased pigment accumulation, increased cellular senescence and increased stiffness), outflow facility, a measure of conventional outflow tissue fluid conductivity, was stable with age. We conclude that the murine conventional outflow system has significant functional reserve in healthy eyes. However, these age-related changes, when combined with other underlying factors, such as genetic susceptibility, are expected to increase risk for ocular hypertension and glaucoma.
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7
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Suarez MF, Schmitt HM, Kuhn MS, Watkins T, Hake KM, Weisz T, Flynn EJ, Elliott MH, Hauser MA, Stamer WD. Genetic background determines severity of Loxl1-mediated systemic and ocular elastosis in mice. Dis Model Mech 2023; 16:dmm050392. [PMID: 37905384 PMCID: PMC10668029 DOI: 10.1242/dmm.050392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 10/20/2023] [Indexed: 11/02/2023] Open
Abstract
Pseudoexfoliation syndrome (PEX) is a systemic, age-related disorder characterized by elastosis and extracellular matrix deposits. Its most significant ocular manifestation is an aggressive form of glaucoma associated with variants in the gene encoding lysyl oxidase-like 1 (LOXL1). Depending upon the population, variants in LOXL1 can impart risk or protection for PEX, suggesting the importance of genetic context. As LOXL1 protein levels are lower and the degree of elastosis is higher in people with PEX, we studied Loxl1-deficient mice on three different genetic backgrounds: C57BL/6 (BL/6), 129S×C57BL/6 (50/50) and 129S. Early onset and high prevalence of spontaneous pelvic organ prolapse in BL/6 Loxl1-/- mice necessitated the study of mice that were <2 months old. Similar to pelvic organ prolapse, most elastosis endpoints were the most severe in BL/6 Loxl1-/- mice, including skin laxity, pulmonary tropoelastin accumulation, expansion of Schlemm's canal and dilation of intrascleral veins. Interestingly, intraocular pressure was elevated in 50/50 Loxl1-/- mice, depressed in BL/6 Loxl1-/- mice and unchanged in 129S Loxl1-/- mice compared to that of control littermates. Overall, the 129S background was protective against most elastosis phenotypes studied. Thus, repair of elastin-containing tissues is impacted by the abundance of LOXL1 and genetic context in young animals.
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Affiliation(s)
- Maria F. Suarez
- Department of Ophthalmology, Duke University, Durham, NC 27705, USA
| | - Heather M. Schmitt
- Department of Ophthalmology, Duke University, Durham, NC 27705, USA
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27701, USA
| | - Megan S. Kuhn
- Department of Ophthalmology, Duke University, Durham, NC 27705, USA
| | - TeddiJo Watkins
- Department of Ophthalmology, Duke University, Durham, NC 27705, USA
| | - Kristyn M. Hake
- Department of Ophthalmology, Duke University, Durham, NC 27705, USA
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27701, USA
| | - Tara Weisz
- Department of Ophthalmology, Duke University, Durham, NC 27705, USA
| | - Edward J. Flynn
- Department of Ophthalmology, Duke University, Durham, NC 27705, USA
| | - Michael H. Elliott
- Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Michael A. Hauser
- Department of Ophthalmology, Duke University, Durham, NC 27705, USA
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27701, USA
- Department of Medicine, Duke University, Durham, NC 27710, USA
| | - W. Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, NC 27705, USA
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8
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Carmichael-Martins A, Gast TJ, King BJ, Walker BR, Sobczak M, Burns SA. Imaging fine structures of the human trabecular meshwork in vivo using a custom design goniolens and OCT gonioscopy. BIOMEDICAL OPTICS EXPRESS 2023; 14:5267-5281. [PMID: 37854570 PMCID: PMC10581814 DOI: 10.1364/boe.500623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/05/2023] [Accepted: 09/06/2023] [Indexed: 10/20/2023]
Abstract
The trabecular meshwork (TM), located within the iridocorneal angle, is a target for many glaucoma treatments aimed at controlling intraocular pressure. However, structural variations between individuals are poorly understood. We propose a newly designed gonioscopic lens optimized for high-resolution imaging to image fine structures of the human TM in vivo. The body of the new lens is index-matched to the human cornea and includes a choice of two gonioscopic mirrors (59° and 63°) and matching air-spaced doublets placed on the anterior surface of the goniolens. The new design allows a diffraction-limited image plane at the iridocorneal angle structures. The goniolens design was built and then placed on the subjectś eyes coupled to the cornea with goniogel and a 3D adjustable mount. Images were obtained using a commercially available OCT device (Heidelberg Spectralis). The optical resolution was measured in a model eye as 40.32 and 45.25 cy/mm respectively for each mirror angle. In humans, dense OCT scans with minimum spacing oriented tangential to the iris and ICA were performed on 7 healthy subjects (23-73 yrs). The TM was successfully imaged in all subjects. The custom goniolens improved the contrast of the uveoscleral meshwork structures and corneoscleral meshwork revealing limbus parallel striations, not visible with previous goniolens designs. Transverse OCT images were constructed along the segmentation line, providing an enface image of the TM structures including corneoscleral beams, previously only imaged in vivo using custom adaptive optics systems.
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Affiliation(s)
| | - Thomas J. Gast
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Brett J. King
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Brittany R. Walker
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Marcelina Sobczak
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Stephen A. Burns
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
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Li H, Kuhn M, Kelly RA, Singh A, Palanivel KK, Salama I, De Ieso ML, Stamer WD, Ganapathy PS, Herberg S. Targeting YAP mechanosignaling to ameliorate stiffness-induced Schlemm's canal cell pathobiology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.08.556840. [PMID: 37781615 PMCID: PMC10541092 DOI: 10.1101/2023.09.08.556840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Pathologic alterations in the biomechanical properties of the Schlemm's canal (SC) inner wall endothelium and its immediate vicinity are strongly associated with ocular hypertension in glaucoma due to decreased outflow facility. Specifically, the underlying trabecular meshwork is substantially stiffer in glaucomatous eyes compared to that from normal eyes. This raises the possibility of a critical involvement of mechanotransduction processes in driving SC cell dysfunction. Yes-associated protein (YAP) has emerged as a key contributor to glaucoma pathogenesis. However, the molecular underpinnings of SC cell YAP mechanosignaling in response to glaucomatous extracellular matrix (ECM) stiffening are not well understood. Using a novel biopolymer hydrogel that facilitates dynamic and reversible stiffness tuning, we investigated how ECM stiffening modulates YAP activity in primary human SC cells, and whether disruption of YAP mechanosignaling attenuates SC cell pathobiology and increases ex vivo outflow facility. We demonstrated that ECM stiffening drives pathologic YAP activation and cytoskeletal reorganization in SC cells, which was fully reversible by matrix softening in a distinct time-dependent manner. Furthermore, we showed that pharmacologic or genetic disruption of YAP mechanosignaling abrogates stiffness-induced SC cell dysfunction involving altered cytoskeletal and ECM remodeling. Lastly, we found that perfusion of the clinically-used, small molecule YAP inhibitor verteporfin (without light activation) increases ex vivo outflow facility in normal mouse eyes. Collectively, our data provide new evidence for a pathologic role of aberrant YAP mechanosignaling in SC cell dysfunction and suggest that YAP inhibition has therapeutic value for treating ocular hypertension in glaucoma.
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Affiliation(s)
- Haiyan Li
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Megan Kuhn
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC 27708, USA
| | - Ruth A. Kelly
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC 27708, USA
| | - Ayushi Singh
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Kavipriya Kovai Palanivel
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Izzy Salama
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Michael L. De Ieso
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC 27708, USA
| | - W. Daniel Stamer
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC 27708, USA
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Preethi S. Ganapathy
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Samuel Herberg
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY 13244, USA
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10
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Kelly RA, McDonnell FS, De Ieso ML, Overby DR, Stamer WD. Pressure Clamping During Ocular Perfusions Drives Nitric Oxide-Mediated Washout. Invest Ophthalmol Vis Sci 2023; 64:36. [PMID: 37358489 PMCID: PMC10297780 DOI: 10.1167/iovs.64.7.36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 05/30/2023] [Indexed: 06/27/2023] Open
Abstract
Purpose The aim of this study was to test the hypothesis that nitric oxide (NO) mediates a pressure-dependent, negative feedback loop that maintains conventional outflow homeostasis and thus IOP. If true, holding pressure during ocular perfusions will result in uncontrolled production of NO, hyper-relaxation of the trabecular meshwork, and washout. Methods Paired porcine eyes were perfused at constant pressure of 15 mm Hg. After 1 hour acclimatization, one eye was exchanged with N5-[imino(nitroamino)methyl]-L-ornithine, methyl ester, monohydrochloride (L-NAME) (50 µm) and the contralateral eye with DBG, and perfused for 3 hours. In a separate group, one eye was exchanged with DETA-NO (100 nM) and the other with DBG and perfused for 30 minutes. Changes in conventional outflow tissue function and morphology were monitored. Results Control eyes exhibited a washout rate of 15% (P = 0.0026), whereas eyes perfused with L-NAME showed a 10% decrease in outflow facility from baseline over 3 hours (P < 0.01); with nitrite levels in effluent positively correlating with time and facility. Compared with L-NAME-treated eyes, significant morphological changes in control eyes included increased distal vessel size, number of giant vacuoles, and juxtacanalicular tissue separation from the angular aqueous plexi (P < 0.05). For 30-minute perfusions, control eyes showed a washout rate of 11% (P = 0.075), whereas DETA-NO-treated eyes showed an increased washout rate of 33% from baseline (P < 0.005). Compared with control eyes, significant morphological changes in DETA-NO-treated eyes also included increased distal vessel size, number of giant vacuoles and juxtacanalicular tissue separation (P < 0.05). Conclusions Uncontrolled NO production is responsible for washout during perfusions of nonhuman eyes where pressure is clamped.
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Affiliation(s)
- Ruth A. Kelly
- Ophthalmology Department, Duke University, Durham, North Carolina, United States
| | - Fiona S. McDonnell
- Ophthalmology Department, Duke University, Durham, North Carolina, United States
- Ophthalmology Department, University of Utah, Utah, United States
| | - Michael L. De Ieso
- Ophthalmology Department, Duke University, Durham, North Carolina, United States
| | - Darryl R. Overby
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - W. Daniel Stamer
- Ophthalmology Department, Duke University, Durham, North Carolina, United States
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11
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Ing E, Lozano DC, Cepurna WO, Chan F, Yang YF, Morrison JC, Keller KE. A method describing the microdissection of trabecular meshwork tissue from Brown Norway rat eyes. Exp Eye Res 2023; 228:109367. [PMID: 36740159 PMCID: PMC9991013 DOI: 10.1016/j.exer.2022.109367] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/29/2022] [Accepted: 12/23/2022] [Indexed: 02/05/2023]
Abstract
Glaucoma is often associated with elevated intraocular pressure (IOP), generally due to obstruction of aqueous humor outflow within the trabecular meshwork (TM). Despite many decades of research, the molecular cause of this obstruction remains elusive. To study IOP regulation, several in vitro models, such as perfusion of anterior segments or mechanical stretching of TM cells, have identified several IOP-responsive genes and proteins. While these studies have proved informative, they do not fully recapitulate the in vivo environment where IOP is subject to additional factors, such as circadian rhythms. Thus, rodent animal models are now commonly used to study IOP-responsive genes in vivo. Several single-cell RNAseq studies have been performed where angle tissue, containing cornea, iris, ciliary body tissue in addition to TM, is dissected. However, it is advantageous to physically separate TM from other tissues because the ratio of TM cells is relatively low compared to the other cell types. In this report, we describe a new technique for rat TM microdissection. Evaluating tissue post-dissection by histology and immunostaining clearly shows successful removal of the TM. In addition, TaqMan PCR primers targeting biomarkers of trabecular meshwork (Myoc, Mgp, Chi3l1) or ciliary body (Myh11, Des) genes showed little contamination of TM tissue by the ciliary body. Finally, pitfalls encountered during TM microdissection are discussed to enable others to successfully perform this microsurgical technique in the rat eye.
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Affiliation(s)
- Eliesa Ing
- Casey Eye Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - Diana C Lozano
- Casey Eye Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - William O Cepurna
- Casey Eye Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - Fountane Chan
- Casey Eye Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - Yong-Feng Yang
- Casey Eye Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - John C Morrison
- Casey Eye Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - Kate E Keller
- Casey Eye Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA.
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12
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Qiao Y, Sun Z, Tan C, Lai J, Sun X, Chen J. Intracameral Injection of AAV-DJ.COMP-ANG1 Reduces the IOP of Mice by Reshaping the Trabecular Outflow Pathway. Invest Ophthalmol Vis Sci 2022; 63:15. [PMID: 36520455 PMCID: PMC9769031 DOI: 10.1167/iovs.63.13.15] [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] [Indexed: 12/23/2022] Open
Abstract
Purpose The angiopoietin-1 (ANG1)-TIE signaling pathway orchestrates the development and maintenance of the Schlemm's canal (SC). In this study, we investigated the impact of adeno-associated virus (AAV)-mediated gene therapy with cartilage oligomeric matrix protein-ANG1 (COMP-ANG1) on trabecular outflow pathway. Methods Different serotypes of AAVs were compared for transduction specificity and efficiency in the anterior segment. The selected AAVs encoding COMP-ANG1 or ZsGreen1 (control) were delivered into the anterior chambers of wild-type C57BL/6J mice. The IOP and ocular surface were monitored regularly. Ocular perfusion was performed to measure the outflow facility and label flow patterns of the trabecular drainage pathway. Structural features of SC as well as limbal, retinal, and skin vessels were visualized by immunostaining. Ultrastructural changes in the SC and trabecular meshwork were observed under transmission electron microscopy. Results AAV-DJ could effectively infect the anterior segment. Intracameral injection of AAV-DJ.COMP-ANG1 lowered IOP in wild-type C57BL/6J mice. No signs of inflammation or angiogenesis were noticed. Four weeks after AAV injection, the conventional outflow facility and effective filtration area were increased significantly (P = 0.005 and P = 0.04, respectively). Consistently, the area of the SC was enlarged (P < 0.001) with increased density of giant vacuoles in the inner wall (P = 0.006). In addition, the SC endothelia lay on a more discontinuous basement membrane (P = 0.046) and a more porous juxtacanalicular tissue (P = 0.005) in the COMP-ANG1 group. Conclusions Intracamerally injected AAV-DJ.COMP-ANG1 offers a significant IOP-lowering effect by remodeling the trabecular outflow pathway of mouse eyes.
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Affiliation(s)
- Yunsheng Qiao
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Zhongmou Sun
- University of Rochester, School of Medicine and Dentistry, Rochester, New York, New York, United States
| | - Chen Tan
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Junyi Lai
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China,State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China,NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China
| | - Junyi Chen
- Department of Ophthalmology & Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China,State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China,NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, and Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China
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13
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Segmental outflow dynamics in the trabecular meshwork of living mice. Exp Eye Res 2022; 225:109285. [PMID: 36273576 DOI: 10.1016/j.exer.2022.109285] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 12/29/2022]
Abstract
Aqueous humour does not drain uniformly through the trabecular meshwork (TM), but rather follows non-uniform or "segmental" routes. In this study, we examined whether segmental outflow patterns in the TM change over time in living mice and whether such changes are affected by age. Segmental outflow patterns were labelled by constant-pressure infusion of fluorescent tracer microparticles into the anterior chamber of anesthetised C57BL/6J mice at 3 or 8 months of age. Two different tracer colours were infused at separate time points with an interval of Δt = 0, 2, 7 or 14 days. In a separate experiment, one tracer was infused in vivo while the second tracer was infused ex vivo after 2 days. The spatial relationship between the two tracer patterns was analysed using the Pearson's correlation coefficient, r. In 3-month-old mice, there was a time-dependent decay in r, which was near unity at Δt = 0 and near zero at Δt = 14 days. In 8-month-old mice, r remained elevated for 14 days. Segmental outflow patterns measured in young mice ex vivo were not significantly different from those measured in vivo after accounting for the expected changes over 2 days. Therefore, segmental outflow patterns are not static in the TM but redistribute over time, achieving near complete loss of correlation by 2 weeks in young healthy mice. There is an age-related decline in the rate at which segmental outflow patterns redistribute in the TM. Further research is needed to understand the dynamic factors controlling segmental outflow.
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14
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Carmichael-Martins A, Gast TJ, Burns SA, Walker BR, King BJ. Characterization of the human iridocorneal angle in vivo using a custom design goniolens with OCT gonioscopy. BIOMEDICAL OPTICS EXPRESS 2022; 13:4652-4667. [PMID: 36187241 PMCID: PMC9484429 DOI: 10.1364/boe.465317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/18/2022] [Accepted: 07/27/2022] [Indexed: 06/16/2023]
Abstract
Intraocular pressure (IOP) is the only modifiable risk factor for glaucoma progression, and many treatments target the trabecular meshwork (TM). Imaging this region in vivo is challenging due to optical limitations of imaging through the cornea at high angles. We propose a gonioscopic OCT approach using a custom goniolens and a commercially available OCT device to improve imaging of the TM, Schlemm's canal (SC) and adjacent structures within the iridocorneal angle (ICA). The goniolens is modified with a plano-convex focusing lens and placed on the eye optically mated with goniogel and aided by a 3D adjustable mount. Gonioscopic OCT volume scans are acquired to image SC. Transverse enface images allowed measurements of SC over a 45° section of the ICA for the first time and revealed locations of SC narrowing. The band of extracanalicular limbal lamina and corneoscleral bands were imaged in most subjects and these bands were confirmed using exterior OCT imaging. The polarization dependence of the visibility of these structures is studied by polarization rotation the OCT beam with a half-wave plate, allowing increased contrast of SC. Gonioscopic OCT has successfully been used to image the human ICA in 3D in vivo. This approach provides more detailed characterization of the TM and SC, enhancing their contrast against their birefringent backgrounds.
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Affiliation(s)
| | - Thomas J. Gast
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Stephen A. Burns
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Brittany R. Walker
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Brett J. King
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
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15
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Mavlyutov TA, Myrah JJ, Chauhan AK, Liu Y, McDowell CM. Fibronectin extra domain A (FN-EDA) causes glaucomatous trabecular meshwork, retina, and optic nerve damage in mice. Cell Biosci 2022; 12:72. [PMID: 35619185 PMCID: PMC9137085 DOI: 10.1186/s13578-022-00800-y] [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: 11/01/2021] [Accepted: 04/27/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Elevated intraocular pressure (IOP) is a major risk factor for the development and progression of primary open angle glaucoma and is due to trabecular meshwork (TM) damage. Here, we investigate the role of an endogenous Toll-like receptor 4 (TLR4) ligand, FN-EDA, in the development of glaucoma utilizing a transgenic mouse strain (B6.EDA+/+) that constitutively expresses only FN containing the EDA isoform. METHODS Eyes from C57BL6/J (wild-type), B6.EDA+/+ (constitutively active EDA), B6.EDA-/- (EDA null) mice were processed for electron microscopy and consecutive images of the entire length of the TM and Schlemm's canal (SC) from anterior to posterior were collected and montaged into a single image. ECM accumulation, basement membrane length, and size and number of giant vacuoles were quantified by ImageJ analysis. Tlr4 and Iba1 expression in the TM and ONH cells was conducted using RNAscope in situ hybridization and immunohistochemistry protocols. IOP was measured using a rebound tonometer, ON damage assessed by PPD stain, and RGC loss quantified in RBPMS labeled retina flat mounts. RESULTS Ultrastructure analyses show the TM of B6.EDA+/+ mice have significantly increased accumulation of ECM between TM beams with few empty spaces compared to C57BL/6 J mice (p < 0.05). SC basement membrane is thicker and more continuous in B6.EDA+/+ mice compared to C57BL/6 J. No significant structural differences are detected in the TM of EDA null mice. Tlr4 and Iba1 expression is increased in the TM of B6.EDA+/+ mice compared to C57BL/6 J eyes (p < 0.05). IOP is significantly higher in B6.EDA+/+ mice compared to C57BL/6 J eyes (p < 0.001), and significant ON damage (p < 0.001) and RGC loss (p < 0.05) detected at 1 year of age. Tlr4 mRNA is expressed in mouse ONH cells, and is present in ganglion cell axons, microglia, and astrocytes. There is a significant increase in the area occupied by Iba-1 positive microglia cells in the ONH of B6.EDA+/+ mice compared to C57BL/6 J control eyes (p < 0.01). CONCLUSIONS B6.EDA+/+ mice have increased ECM accumulation in the TM, elevated IOP, enhanced proinflammatory changes in the ONH, loss of RGCs, and ONH damage. These data suggest B6.EDA+/+ mice recapitulate many aspects of glaucomatous damage.
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Affiliation(s)
- Timur A. Mavlyutov
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI USA
| | - Justin J. Myrah
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI USA
| | - Anil K. Chauhan
- Department of Internal Medicine, Division of Hematology/Oncology, University of Iowa, Iowa City, IA USA
| | - Yang Liu
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX USA
| | - Colleen M. McDowell
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI USA
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16
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Al-khersan H, Jr HWF, Townsend JH. Retinal Detachments Associated with Topical Pilocarpine Use for Presbyopia: Pilocarpine-Associated Retinal Detachments. Am J Ophthalmol 2022; 242:52-55. [PMID: 35609677 DOI: 10.1016/j.ajo.2022.05.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 05/14/2022] [Accepted: 05/17/2022] [Indexed: 11/01/2022]
Abstract
PURPOSE To present a case series of retinal detachments associated with the use of pilocarpine for presbyopia. DESIGN Multicenter case series of 3 eyes from 2 patients. RESULTS Patient 1, a 47-year-old male, presented with flashes and floaters in both eyes. The patient had started pilocarpine 1.25% drops one month prior for presbyopia in both eyes. He noted the onset of flashes and floaters three days after he initiated the drops. A dilated examination revealed an inferotemporal retinal detachment in the right eye with an associated retinal tear inferotemporally. The left eye demonstrated a retinal detachment in the superior quadrant with an associated horseshoe tear at 12 o'clock. Patient 2, a 46-year-old male, presented 5 weeks after initiating topical pilocarpine 1.25% drops for presbyopia. He noted a nasal visual field defect in his left eye that progressed to include his central vision. A dilated examination revealed a superior retinal detachment from 11 to 3 o'clock with subretinal fluid extending into the macula. CONCLUSIONS AND IMPORTANCE Pilocarpine and other miotics have long been suspected to be associated with an increased risk of retinal detachment. Prior to prescribing pilocarpine for presbyopia, physicians should inform patients of this potential adverse event and consider that these patients undergo a screening dilated examination, particularly if they are myopic, to determine if they are at higher risk for retinal detachment. Before the initiation of therapy, patients should be appropriately informed regarding symptoms of retinal tears or detachment, which include flashes, floaters, and visual field loss.
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17
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Madekurozwa M, Reina-Torres E, Overby DR, van Batenburg-Sherwood J. Measurement of postmortem outflow facility using iPerfusion. Exp Eye Res 2022; 220:109103. [PMID: 35525299 DOI: 10.1016/j.exer.2022.109103] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/24/2022] [Accepted: 04/28/2022] [Indexed: 11/04/2022]
Abstract
The key risk factor for glaucoma is elevation of intraocular pressure (IOP) and alleviating it is the only effective therapeutic approach to inhibit further vision loss. IOP is regulated by the flow of aqueous humour across resistive tissues, and a reduction in outflow facility C, is responsible for the IOP elevation in glaucoma. Measurement of C is therefore important when investigating the pathophysiology of glaucoma and testing candidate treatments for lowering IOP. Due to similar anatomy and response to pharmacological treatments, mouse eyes are a common model of human aqueous humour dynamics. The ex vivo preparation, in which an enucleated mouse eye is mounted in a temperature controlled bath and cannulated, has been well characterised and is widely used. The postmortem in situ model, in which the eyes are perfused within the cadaver, has received relatively little attention. In this study, we investigate the postmortem in situ model using the iPerfusion system, with a particular focus on i) the presence or absence of pressure-independent flow, ii) the effect of evaporation on measured flow rates and iii) the magnitude and pressure dependence of outflow facility and how these properties are affected by postmortem changes. Measurements immediately after cannulation and following multi-pressure facility measurement demonstrated negligible pressure-independent flow in postmortem eyes, in contrast to assumptions made in previous studies. Using a humidity chamber, we investigated whether the humidity of the surrounding air would influence measured flow rates. We found that at room levels of humidity, evaporation of saline droplets on the eye resulted in artefactual flow rates with a magnitude comparable to outflow, which were eliminated by a high relative humidity (>85%) environment. Average postmortem outflow facility was ∼4 nl/min/mmHg, similar to values observed ex vivo, irrespective of whether a postmortem delay was introduced prior to cannulation. The intra-animal variability of measured outflow facility values was also reduced relative to previous ex vivo data. The pressure-dependence of outflow facility was reduced in the postmortem relative to ex vivo model, and practically eliminated when eyes were cannulated >40 min after euthanisation. Overall, our results indicate that the moderately increased technical complexity associated with postmortem perfusion provides reduced variability and reduced pressure-dependence in outflow facility, when experimental conditions are properly controlled.
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Affiliation(s)
| | | | - Darryl R Overby
- Dept. of Bioengineering, Imperial College London, London, SW7 2AZ, UK.
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18
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McDowell CM, Kizhatil K, Elliott MH, Overby DR, van Batenburg-Sherwood J, Millar JC, Kuehn MH, Zode G, Acott TS, Anderson MG, Bhattacharya SK, Bertrand JA, Borras T, Bovenkamp DE, Cheng L, Danias J, De Ieso ML, Du Y, Faralli JA, Fuchshofer R, Ganapathy PS, Gong H, Herberg S, Hernandez H, Humphries P, John SWM, Kaufman PL, Keller KE, Kelley MJ, Kelly RA, Krizaj D, Kumar A, Leonard BC, Lieberman RL, Liton P, Liu Y, Liu KC, Lopez NN, Mao W, Mavlyutov T, McDonnell F, McLellan GJ, Mzyk P, Nartey A, Pasquale LR, Patel GC, Pattabiraman PP, Peters DM, Raghunathan V, Rao PV, Rayana N, Raychaudhuri U, Reina-Torres E, Ren R, Rhee D, Chowdhury UR, Samples JR, Samples EG, Sharif N, Schuman JS, Sheffield VC, Stevenson CH, Soundararajan A, Subramanian P, Sugali CK, Sun Y, Toris CB, Torrejon KY, Vahabikashi A, Vranka JA, Wang T, Willoughby CE, Xin C, Yun H, Zhang HF, Fautsch MP, Tamm ER, Clark AF, Ethier CR, Stamer WD. Consensus Recommendation for Mouse Models of Ocular Hypertension to Study Aqueous Humor Outflow and Its Mechanisms. Invest Ophthalmol Vis Sci 2022; 63:12. [PMID: 35129590 PMCID: PMC8842499 DOI: 10.1167/iovs.63.2.12] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/08/2021] [Indexed: 01/07/2023] Open
Abstract
Due to their similarities in anatomy, physiology, and pharmacology to humans, mice are a valuable model system to study the generation and mechanisms modulating conventional outflow resistance and thus intraocular pressure. In addition, mouse models are critical for understanding the complex nature of conventional outflow homeostasis and dysfunction that results in ocular hypertension. In this review, we describe a set of minimum acceptable standards for developing, characterizing, and utilizing mouse models of open-angle ocular hypertension. We expect that this set of standard practices will increase scientific rigor when using mouse models and will better enable researchers to replicate and build upon previous findings.
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Affiliation(s)
- Colleen M. McDowell
- Department of Ophthalmology and Visual Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | | | - Michael H. Elliott
- University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Darryl R. Overby
- Department of Bioengineering, Imperial College London, United Kingdom
| | | | - J. Cameron Millar
- Department of Pharmacology & Neuroscience, and North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Markus H. Kuehn
- Department of Ophthalmology and Visual Sciences and Institute for Vision Research, The University of Iowa; Center for the Prevention and Treatment of Visual Loss, Veterans Affairs Medical Center, Iowa City, Iowa, United States
| | - Gulab Zode
- Department of Pharmacology & Neuroscience, and North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Ted S. Acott
- Ophthalmology and Biochemistry and Molecular Biology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Michael G. Anderson
- Department of Molecular Physiology and Biophysics and Department of Ophthalmology and Visual Sciences, The University of Iowa; Center for the Prevention and Treatment of Visual Loss, Veterans Affairs Medical Center, Iowa City, Iowa, United States
| | | | - Jacques A. Bertrand
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Terete Borras
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | | | - Lin Cheng
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States
| | - John Danias
- SUNY Downstate Health Sciences University, Brooklyn, New York, United States
| | - Michael Lucio De Ieso
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, North Carolina, United States
| | - Yiqin Du
- Department of Ophthalmology, University of Pittsburgh, Pennsylvania, United States
| | - Jennifer A. Faralli
- Department of Pathology and Laboratory Medicine, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Rudolf Fuchshofer
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
| | - Preethi S. Ganapathy
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
| | - Haiyan Gong
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Samuel Herberg
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
| | | | - Peter Humphries
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Simon W. M. John
- Department of Ophthalmology, Columbia University, New York, New York, United States
| | - Paul L. Kaufman
- Department of Ophthalmology and Visual Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Kate E. Keller
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Mary J. Kelley
- Department of Ophthalmology and Department of Integrative Biosciences, Oregon Health & Science University, Portland, Oregon, United States
| | - Ruth A. Kelly
- Ocular Genetics Unit, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - David Krizaj
- Department of Ophthalmology, University of Utah School of Medicine, Salt Lake City, Utah, United States
| | - Ajay Kumar
- Department of Ophthalmology, University of Pittsburgh, Pennsylvania, United States
| | - Brian C. Leonard
- Department of Surgical and Radiological Sciences, University of California, Davis, Davis, California, United States
| | - Raquel L. Lieberman
- Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, United States
| | - Paloma Liton
- Department of Ophthalmology and Department of Pathology, Duke University, Durham, North Carolina, United States
| | - Yutao Liu
- Department of Cellular Biology and Anatomy, James & Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, United States
| | - Katy C. Liu
- Duke Eye Center, Duke Health, Durham, North Carolina, United States
| | - Navita N. Lopez
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, United States
| | - Weiming Mao
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Timur Mavlyutov
- Department of Ophthalmology and Visual Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Fiona McDonnell
- Duke Eye Center, Duke Health, Durham, North Carolina, United States
| | - Gillian J. McLellan
- Department of Surgical Sciences and Department of Ophthalmology and Visual Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Philip Mzyk
- Department of Ophthalmology and Visual Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Andrews Nartey
- College of Optometry, University of Houston, Houston, Texas, United States
| | - Louis R. Pasquale
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York, United States
| | - Gaurang C. Patel
- Ophthalmology Research, Regeneron Pharmaceuticals, Tarreytown, New York, United States
| | | | - Donna M. Peters
- Department of Pathology and Laboratory Medicine, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | | | - Ponugoti Vasantha Rao
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, United States
| | - Naga Rayana
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Urmimala Raychaudhuri
- Department of Neurobiology, University of California, Irvine, Irvine, California, United States
| | - Ester Reina-Torres
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Ruiyi Ren
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Douglas Rhee
- Case Western Reserve University School of Medicine, Cleveland, Ohio, United States
| | - Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - John R. Samples
- Washington State University, Floyd Elson College of Medicine, Spokane, Washington, United States
| | | | - Najam Sharif
- Santen Inc., Emeryville, California, United States
| | - Joel S. Schuman
- Department of Ophthalmology and Department of Physiology and Neuroscience, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, New York, United States; Departments of Biomedical Engineering and Electrical and Computer Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States; Center for Neural Science, College of Arts and Science, New York University, New York, New York, United States
| | - Val C. Sheffield
- Department of Pediatrics and Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
| | - Cooper H. Stevenson
- Department of Pharmacology & Neuroscience, and North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Avinash Soundararajan
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | | | - Chenna Kesavulu Sugali
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Yang Sun
- Veterans Affairs Palo Alto Health Care System, Stanford University, Palo Alto, California, United States
| | - Carol B. Toris
- Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, Nebraska, United States; Department of Ophthalmology and Vision Sciences, The Ohio State University, Columbus, Ohio, United States
| | | | - Amir Vahabikashi
- Cell and Developmental Biology Department, Northwestern University, Chicago, Illinois, United States
| | - Janice A. Vranka
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Ting Wang
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Colin E. Willoughby
- Genomic Medicine, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Chen Xin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Hongmin Yun
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Hao F. Zhang
- Biomedical Engineering Department, Northwestern University, Evanston, Illinois, United States
| | - Michael P. Fautsch
- Biomedical Engineering Department, Northwestern University, Evanston, Illinois, United States
| | | | - Abbot F. Clark
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - C. Ross Ethier
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology; Emory University School of Medicine, Emory University, Atlanta, Georgia, United States
| | - W. Daniel Stamer
- Duke Ophthalmology, Duke University, Durham, North Carolina, United States
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19
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Roy Chowdhury U, Millar JC, Holman BH, Anderson KJ, Dosa PI, Roddy GW, Fautsch MP. Effect of ATP-sensitive Potassium Channel Openers on Intraocular Pressure in Ocular Hypertensive Animal Models. Invest Ophthalmol Vis Sci 2022; 63:15. [PMID: 35129587 PMCID: PMC8822368 DOI: 10.1167/iovs.63.2.15] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Purpose To evaluate the effect of ATP-sensitive potassium channel openers cromakalim prodrug 1 (CKLP1) and diazoxide on IOP in three independent mouse models of ocular hypertension. Methods Baseline IOP was measured in TGFβ2 overexpression, steroid-induced, and iris dispersion (DBA/2J) ocular hypertension mouse models, followed by once daily eyedrop administration with CKLP1 (5 mM) or diazoxide (5 mM). The IOP was measured in conscious animals with a handheld rebound tonometer. Aqueous humor dynamics were assessed by a constant perfusion method. Effect of treatment on ocular tissues was evaluated by transmission electron microscopy. Results CKLP1 decreased the IOP by 20% in TGFβ2 overexpressing mice (n = 6; P < 0.0001), 24% in steroid-induced ocular hypertensive mice (n = 8; P < 0.0001), and 43% in DBA/2J mice (n = 15; P < 0.0001). Diazoxide decreased the IOP by 32% in mice with steroid-induced ocular hypertension (n = 13; P < 0.0001) and by 41% in DBA/2J mice (n = 4; P = 0.005). An analysis of the aqueous humor dynamics revealed that CKLP1 decreased the episcleral venous pressure by 29% in TGFβ2 overexpressing mice (n = 13; P < 0.0001) and by 72% in DBA/2J mice (n = 4 control, 3 treated; P = 0.0002). Diazoxide lowered episcleral venous pressure by 35% in steroid-induced ocular hypertensive mice (n = 3; P = 0.03). Tissue histology and cell morphology appeared normal when compared with controls. Accumulation of extracellular matrix was reduced in CKLP1- and diazoxide-treated eyes in the steroid-induced ocular hypertension model. Conclusions ATP-sensitive potassium channel openers CKLP1 and diazoxide effectively decreased the IOP in ocular hypertensive animal models by decreasing the episcleral venous pressure, supporting a potential therapeutic application of these agents in ocular hypertension and glaucoma.
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Affiliation(s)
| | - J Cameron Millar
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Bradley H Holman
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States
| | | | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Gavin W Roddy
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States
| | - Michael P Fautsch
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States
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20
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Sankalp, Dada T, Yadav RK, Sharma HB, Netam RK, Kochhar KP. Effect of Tratak (Yogic Ocular Exercises) on Intraocular Pressure in Glaucoma: An RCT. Int J Yoga 2022; 15:59-69. [PMID: 35444375 PMCID: PMC9015087 DOI: 10.4103/ijoy.ijoy_160_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 01/31/2022] [Accepted: 01/31/2022] [Indexed: 11/29/2022] Open
Abstract
INTRODUCTION In healthy subjects, the intraocular pressure (IOP) is maintained by a dynamic equilibrium between continuous production of aqueous humor by ciliary bodies and continuous outflow through the two drainage pathways: trabecular meshwork and uveoscleral outflow. Here, we hypothesized that yogic ocular exercises, including extraocular muscles exercise, and modified Tratak Kriya (mTK), might reduce the IOP as well as stress and improve quality of life (QoL) in patients with glaucoma. METHODOLOGY A parallel two-arm randomized controlled trial (RCT) was conducted in glaucoma patients (Control group and Intervention group). Control group patients were on standard medical treatment and intervention group patients practiced a Yoga-based lifestyle intervention (YBLI) for 4 weeks as add-on therapy with their standard medical treatment. All Participants were assessed at baseline day 1, day 14 (D14), and day 28 (D28). A minimum of 30 patients were recruited in each group. RESULTS We did not observe any statistically significant different mean IOP of right (IOP-r) or, left eyes at any time point as well as cortisol level and QoL between the two groups. However, with in intervention group, there was a reduction in IOP-r at D14 (15.54 ± 2.81 mmHg) and D28 (15.24 ± 3.1 mmHg), P = 0.006 and 0.001, respectively, compared to their baseline IOP (16.26 ± 2.98). CONCLUSION Based on the present RCT, yoga-based ocular exercises practiced here cannot be recommended for management of raised IOP in glaucoma patients. Further larger studies are warranted with yoga-based interventions in patients with glaucoma. CLINICAL TRIAL REGISTRATION NUMBER CTRI/2016/03/006703.
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Affiliation(s)
- Sankalp
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | - Tanuj Dada
- Department of Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Raj Kumar Yadav
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India,Address for correspondence: Dr. Raj Kumar Yadav, Department of Physiology, All India Institute of Medical Sciences, New Delhi - 110 029, India. E-mail:
| | | | - Ritesh Kumar Netam
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
| | - Kanwal Preet Kochhar
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
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21
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Atta G, Tempfer H, Kaser-Eichberger A, Traweger A, Heindl LM, Schroedl F. Is the human sclera a tendon-like tissue? A structural and functional comparison. Ann Anat 2021; 240:151858. [PMID: 34798297 DOI: 10.1016/j.aanat.2021.151858] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 09/22/2021] [Accepted: 11/09/2021] [Indexed: 12/17/2022]
Abstract
Collagen rich connective tissues fulfill a variety of important functions throughout the human body, most of which having to resist mechanical challenges. This review aims to compare structural and functional aspects of tendons and sclera, two tissues with distinct location and function, but with striking similarities regarding their cellular content, their extracellular matrix and their low degree of vascularization. The description of these similarities meant to provide potential novel insight for both the fields of orthopedic research and ophthalmology.
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Affiliation(s)
- Ghada Atta
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Institute for Tendon and Bone Regeneration, Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Herbert Tempfer
- Institute for Tendon and Bone Regeneration, Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University, Salzburg, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Alexandra Kaser-Eichberger
- Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology - Salzburg, Paracelsus Medical University, Strubergasse 21, 5020 Salzburg, Austria
| | - Andreas Traweger
- Institute for Tendon and Bone Regeneration, Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University, Salzburg, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Ludwig M Heindl
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Center for Integrated Oncology (CIO) Aachen - Bonn - Cologne - Düsseldorf, Cologne, Germany
| | - Falk Schroedl
- Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology - Salzburg, Paracelsus Medical University, Strubergasse 21, 5020 Salzburg, Austria.
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22
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Chen L, Jin W, Hao X, Li X, Xing Y. Dynamic changes of scleral spur length in different accommodation stimuli states. Sci Rep 2021; 11:18176. [PMID: 34518627 PMCID: PMC8438021 DOI: 10.1038/s41598-021-97754-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/30/2021] [Indexed: 11/09/2022] Open
Abstract
This study aimed to evaluate the scleral spur length (SSL) in response to different accommodation stimuli states, as well as the correlation with Schlemm’s canal (SC) and trabecular meshwork (TM). 74 children were recruited for this study. The 0D, − 4D, and − 8.0 D accommodation stimuli state was achieved by looking at a variable distance optotype. The ciliary muscle (CM), scleral spur (SS), SC, and TM were imaged by swept-source optical coherence tomography. The SSL (Method III) increased significantly from 221.56 ± 30.74 μm at base state to 234.99 ± 30.11 μm at − 4D accommodation stimuli state (p = 0.028) and increased to 250.09 ± 29.87 μm at − 8D accommodation stimuli state (p = 0.011). Method III had the largest areas under receiver operating characteristic (ROC) curves (0.798, 95% CI 0.721–0.875). Moreover, CM 1, SC, and trabecular meshwork length (TML) were significantly correlated with SSL (Method III) (p < 0.05). These findings suggest that the contractile ability and compliance of the SS play an important role in maintaining the morphology of the SC. Moreover, the force of accommodation regulates the SC size by increasing the length of SS.
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Affiliation(s)
- Liugui Chen
- Eye Center, Renmin Hospital of Wuhan University, Jiefang Road 238#, Wuchang District, Wuhan, 430060, Hubei Province, China
| | - Wei Jin
- Eye Center, Renmin Hospital of Wuhan University, Jiefang Road 238#, Wuchang District, Wuhan, 430060, Hubei Province, China
| | - Xinlei Hao
- Eye Center, Renmin Hospital of Wuhan University, Jiefang Road 238#, Wuchang District, Wuhan, 430060, Hubei Province, China
| | - Xuejie Li
- Eye Center, Renmin Hospital of Wuhan University, Jiefang Road 238#, Wuchang District, Wuhan, 430060, Hubei Province, China
| | - Yiqiao Xing
- Eye Center, Renmin Hospital of Wuhan University, Jiefang Road 238#, Wuchang District, Wuhan, 430060, Hubei Province, China.
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23
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Lakk M, Križaj D. TRPV4-Rho signaling drives cytoskeletal and focal adhesion remodeling in trabecular meshwork cells. Am J Physiol Cell Physiol 2021; 320:C1013-C1030. [PMID: 33788628 PMCID: PMC8285634 DOI: 10.1152/ajpcell.00599.2020] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Intraocular pressure (IOP) is dynamically regulated by the trabecular meshwork (TM), a mechanosensitive tissue that protects the eye from injury through dynamic regulation of aqueous humor flow. TM compensates for mechanical stress impelled by chronic IOP elevations through increased actin polymerization, tissue stiffness, and contractility. This process has been associated with open angle glaucoma; however, the mechanisms that link mechanical stress to pathological cytoskeletal remodeling downstream from the mechanotransducers remain poorly understood. We used fluorescence imaging and biochemical analyses to investigate cytoskeletal and focal adhesion remodeling in human TM cells stimulated with physiological strains. Mechanical stretch promoted F-actin polymerization, increased the number and size of focal adhesions, and stimulated the activation of the Rho-associated protein kinase (ROCK). Stretch-induced activation of the small GTPase Ras homolog family member A (RhoA), and tyrosine phosphorylations of focal adhesion proteins paxillin, focal adhesion kinase (FAK), vinculin, and zyxin were time dependently inhibited by ROCK inhibitor trans-4-[(1R)-1-aminoethyl]-N-4-pyridinylcyclohexanecarboxamide dihydrochloride (Y-27632), and by HC-067047, an antagonist of transient receptor potential vanilloid 4 (TRPV4) channels. Both TRPV4 and ROCK activation were required for zyxin translocation and increase in the number/size of focal adhesions in stretched cells. Y-27632 blocked actin polymerization without affecting calcium influx induced by membrane stretch and the TRPV4 agonist GSK1016790A. These results reveal that mechanical tuning of TM cells requires parallel activation of TRPV4, integrins, and ROCK, with chronic stress leading to sustained remodeling of the cytoskeleton and focal complexes.
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Affiliation(s)
- Monika Lakk
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah.,Department of Bioengineering, University of Utah, Salt Lake City, Utah.,Department of Neurobiology, University of Utah, Salt Lake City, Utah
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24
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Wu HJ, Kuchtey J, Kuchtey RW. Increased Susceptibility to Glaucomatous Damage in Microfibril Deficient Mice. Invest Ophthalmol Vis Sci 2021; 61:28. [PMID: 32797197 PMCID: PMC7441341 DOI: 10.1167/iovs.61.10.28] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purpose To test whether mice with microfibril deficiency due to the Tsk mutation of fibrillin-1 (Fbn1Tsk/+) have increased susceptibility to pressure-induced retinal ganglion cell (RGC) degeneration. Methods Intraocular pressure (IOP) elevation was induced in Fbn1Tsk/+ and wild type (wt) mice by injecting microbeads into the anterior chamber. Mice were then followed up for four months, with IOP measurements every three to six days. Retinas were stained for Brn3a to determine RGC number. Optic nerve cross-sections were stained with p-phenylene diamine to determine nerve area, axon number, and caliber and thickness of the pia mater. Results Microbead injection induced significant IOP elevation that was significantly less for Fbn1Tsk/+ mice compared with wt. The optic nerves and optic nerve axons were larger, and the elastic fiber-rich pia mater was thinner in Fbn1Tsk/+ mice. Microbead injection resulted in reduced optic nerve size, thicker pia mater, and a slight decrease in axon size. Fbn1Tsk/+ mice had significantly greater loss of RGCs and optic nerve axons compared with wt (14.8% vs. 5.8%, P = 0.002, and 17.0% vs. 7.5%, P = 0.002, respectively). Conclusions Fbn1Tsk/+mice had altered optic nerve structure as indicated by larger optic nerves, larger optic nerve axons and thinner pia mater, consistent with our previous findings. Despite lower IOP elevation, Fbn1Tsk/+mice had greater loss of RGCs and optic nerve axons, suggesting increased susceptibility to IOP-induced optic nerve degeneration in microfibril-deficient mice.
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Affiliation(s)
- Hang-Jing Wu
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - John Kuchtey
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Rachel W Kuchtey
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, Tennessee, United States.,Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, United States
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25
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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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26
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Bertrand JA, Woodward DF, Sherwood JM, Wang JW, Overby DR. The role of EP 2 receptors in mediating the ultra-long-lasting intraocular pressure reduction by JV-GL1. Br J Ophthalmol 2020; 105:1610-1616. [PMID: 33239414 DOI: 10.1136/bjophthalmol-2020-317762] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/23/2020] [Accepted: 10/30/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND A single application of JV-GL1 substantially lowers non-human primate intraocular pressure (IOP) for about a week, independent of dose. This highly protracted effect does not correlate with its ocular biodisposition or correlate with the once-daily dosing regimen for other prostanoid EP2 receptor agonists such as trapenepag or omidenepag. The underlying pharmacological mechanism for the multiday extended activity of JV-GL1 is highly intriguing. The present studies were intended to determine EP2 receptor involvement in mediating the long-term ocular hypotensive activity of JV-GL1 by using mice genetically deficient in EP2 receptors. METHODS The protracted IOP reduction produced by JV-GL1 was investigated in C57BL/6J and EP2 receptor knock-out mice (B6.129-Ptger2tm1Brey /J; EP2KO). Both ocular normotensive and steroid-induced ocular hypertensive (SI-OHT) mice were studied. IOP was measured tonometrically under general anaesthesia. Aqueous humour outflow facility was measured ex vivo using iPerfusion in normotensive C57BL/6J mouse eyes perfused with 100 nM de-esterified JV-GL1 and in SI-OHT C57BL/6J mouse eyes that had received topical JV-GL1 (0.01%) 3 days prior. RESULTS Both the initial 1-day and the protracted multiday effects of JV-GL1 in the SI-OHT model for glaucoma were abolished by deletion of the gene encoding the EP2 receptor. Thus, JV-GL1 did not lower IOP in SI-OHT EP2KO mice, but in littermate SI-OHT EP2WT control mice, JV-GL1 statistically significantly lowered IOP for 4-6 days. CONCLUSIONS Both the 1-day and the long-term effects of JV-GL1 on IOP are entirely EP2 receptor dependent.
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Affiliation(s)
| | - David F Woodward
- Dept. of Bioengineering, Imperial College London, London, UK.,JeniVision Inc, Suite 200, Irvine, California, USA
| | | | - Jenny W Wang
- JeniVision Inc, Suite 200, Irvine, California, USA
| | - Darryl R Overby
- Dept. of Bioengineering, Imperial College London, London, UK
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27
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Li G, Schmitt H, Johnson WM, Lee C, Navarro I, Cui J, Fleming T, Gomez-Caraballo M, Elliott MH, Sherwood JM, Hauser MA, Farsiu S, Ethier CR, Stamer WD. Integral role for lysyl oxidase-like-1 in conventional outflow tissue function and behavior. FASEB J 2020; 34:10762-10777. [PMID: 32623782 DOI: 10.1096/fj.202000702rr] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/02/2020] [Accepted: 06/03/2020] [Indexed: 12/15/2022]
Abstract
Lysyl oxidase-like-1 (LOXL1), a vital crosslinking enzyme in elastin fiber maintenance, is essential for the stability and strength of elastic vessels and tissues. Variants in the LOXL1 locus associate with a dramatic increase in risk of exfoliation syndrome (XFS), a systemic fibrillopathy, which often presents with ocular hypertension and exfoliation glaucoma (XFG). We examined the role of LOXL1 in conventional outflow function, the prime regulator of intraocular pressure (IOP). Using Loxl1-/- , Loxl1+/- , and Loxl1+/+ mice, we observed an inverse relationship between LOXL1 expression and IOP, which worsened with age. Elevated IOP in Loxl1-/- mice was associated with a larger globe, decreased ocular compliance, increased outflow facility, extracellular matrix (ECM) abnormalities, and dilated intrascleral veins, yet, no dilation of arteries or capillaries. Interestingly, in living Loxl1-/- mouse eyes, Schlemm's canal (SC) was less susceptible to collapse when challenged with acute elevations in IOP, suggesting elevated episcleral venous pressure (EVP). Thus, LOXL1 expression is required for normal IOP control, while ablation results in altered ECM repair/homeostasis and conventional outflow physiology. Dilation of SC and distal veins, but not arteries, is consistent with key structural and functional roles for elastin in low-pressure vessels subjected to cyclical mechanical stress.
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Affiliation(s)
- Guorong Li
- Department of Ophthalmology, Duke University, Durham, NC, USA
| | - Heather Schmitt
- Department of Ophthalmology, Duke University, Durham, NC, USA
| | | | - Chanyoung Lee
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA, USA
| | - Iris Navarro
- Department of Ophthalmology, Duke University, Durham, NC, USA
| | - Jenny Cui
- East Chapel Hill School, Chapel Hill, NC, USA
| | - Todd Fleming
- Department of Ophthalmology, Duke University, Durham, NC, USA
| | | | - Michael H Elliott
- Department of Ophthalmology and Physiology, University of Oklahoma Health, Oklahoma City, OK, USA
| | | | - Michael A Hauser
- Department of Ophthalmology, Duke University, Durham, NC, USA.,Molecular Physiology Institute, Duke University, Durham, NC, USA
| | - Sina Farsiu
- Department of Ophthalmology, Duke University, Durham, NC, USA.,Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - C Ross Ethier
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA, USA
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, NC, USA.,Department of Biomedical Engineering, Duke University, Durham, NC, USA
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28
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Li M, Zheng B, Wang Q, Sun X. Impact of Visual Field Testing on Intraocular Pressure Change Trends in Healthy People and Glaucoma Patients. J Ophthalmol 2020; 2020:7936205. [PMID: 32714610 PMCID: PMC7355374 DOI: 10.1155/2020/7936205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/17/2020] [Indexed: 11/17/2022] Open
Abstract
PURPOSE To compare the impact of visual field (VF) testing on intraocular pressure (IOP) change trends between healthy subjects and glaucoma patients. METHODS We recruited healthy volunteer subjects who did not have previous ocular diseases and open-angle glaucoma patients who were medically controlled well. IOP in both eyes of each participant was measured by using a noncontact tonometer at five time points: before, immediately after (0 minute), and 10, 30, and 60 minutes after the standard automated perimetry. Repeated measures ANOVA was used to analyze the effect of VF testing on IOP change trends in healthy and glaucoma eyes. RESULTS Forty healthy subjects (80 eyes) and 31 open-angle glaucoma patients (62 eyes) were included for the study. The baseline IOP of healthy and glaucoma eyes was 16.11 ± 3.01 mmHg and 15.78 ± 3.57 mmHg, respectively. After the VF testing, the IOP in healthy eyes was decreased by 1.5% at 0 minute, 6.5% at 10 minutes (P < 0.001), 6.6% at 30 minutes (P < 0.001), and 7.0% at 1 hour (P < 0.001), indicating that this reduction was sustained for at least 1 hour. However, the IOP in glaucoma eyes was increased by 12.7% at 0 minute (P < 0.001) and, then, returned towards initial values 1 hour after the VF testing. CONCLUSIONS IOP change trends after VF field testing between healthy subjects and glaucoma patients were quite different. VF testing led to a mild and relatively sustained IOP decrease in healthy subjects, whereas IOP in open-angle glaucoma patients tended to significantly increase immediately after VF testing and, then, returned to pretest values after 1 hour. These findings indicate that the factors of VF testing should be considered in the clinical IOP measurements.
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Affiliation(s)
- Mengwei Li
- Department of Ophthalmology and Visual Science, Eye, Ear, Nose and Throat Hospital, Shanghai Medical College of Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China
| | - Bingxin Zheng
- Department of Nursing, Eye, Ear, Nose and Throat Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Qi Wang
- Department of Nursing, Eye, Ear, Nose and Throat Hospital, Shanghai Medical College of Fudan University, Shanghai, China
| | - Xinghuai Sun
- Department of Ophthalmology and Visual Science, Eye, Ear, Nose and Throat Hospital, Shanghai Medical College of Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai Key Laboratory of Visual Impairment and Restoration (Fudan University), Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
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Molecular taxonomy of human ocular outflow tissues defined by single-cell transcriptomics. Proc Natl Acad Sci U S A 2020; 117:12856-12867. [PMID: 32439707 PMCID: PMC7293718 DOI: 10.1073/pnas.2001896117] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ocular hypertension is the primary and only modifiable risk factor for glaucoma, the leading cause of irreversible blindness. Intraocular pressure is regulated homeostatically by resistance to aqueous humor outflow through an architecturally complex tissue, the conventional/trabecular pathway. In this study, we generated a comprehensive cell atlas of the human trabecular meshwork and neighboring tissues using single-cell RNA sequencing. We identified 12 distinct cell types and mapped region-specific expression of candidate genes. The utility of our atlas was demonstrated by mapping glaucoma-relevant genes to conventional outflow cell types. Our study provides a comprehensive molecular and cellular classification of tissue structures responsible for intraocular pressure homeostasis in health and dysregulation in disease. The conventional outflow pathway is a complex tissue responsible for maintaining intraocular pressure (IOP) homeostasis. The coordinated effort of multiple cells with differing responsibilities ensures healthy outflow function and IOP maintenance. Dysfunction of one or more resident cell types results in ocular hypertension and risk for glaucoma, a leading cause of blindness. In this study, single-cell RNA sequencing was performed to generate a comprehensive cell atlas of human conventional outflow tissues. We obtained expression profiles of 17,757 genes from 8,758 cells from eight eyes of human donors representing the outflow cell transcriptome. Upon clustering analysis, 12 distinct cell types were identified, and region-specific expression of candidate genes was mapped in human tissues. Significantly, we identified two distinct expression patterns (myofibroblast- and fibroblast-like) from cells located in the trabecular meshwork (TM), the primary structural component of the conventional outflow pathway. We also located Schwann cell and macrophage signatures in the TM. The second primary component structure, Schlemm’s canal, displayed a unique combination of lymphatic/blood vascular gene expression. Other expression clusters corresponded to cells from neighboring tissues, predominantly in the ciliary muscle/scleral spur, which together correspond to the uveoscleral outflow pathway. Importantly, the utility of our atlas was demonstrated by mapping glaucoma-relevant genes to outflow cell clusters. Our study provides a comprehensive molecular and cellular classification of conventional and unconventional outflow pathway structures responsible for IOP homeostasis.
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van Zyl T, Yan W, McAdams A, Peng YR, Shekhar K, Regev A, Juric D, Sanes JR. Cell atlas of aqueous humor outflow pathways in eyes of humans and four model species provides insight into glaucoma pathogenesis. Proc Natl Acad Sci U S A 2020; 117:10339-10349. [PMID: 32341164 PMCID: PMC7229661 DOI: 10.1073/pnas.2001250117] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Increased intraocular pressure (IOP) represents a major risk factor for glaucoma, a prevalent eye disease characterized by death of retinal ganglion cells; lowering IOP is the only proven treatment strategy to delay disease progression. The main determinant of IOP is the equilibrium between production and drainage of aqueous humor, with compromised drainage generally viewed as the primary contributor to dangerous IOP elevations. Drainage occurs through two pathways in the anterior segment of the eye called conventional and uveoscleral. To gain insights into the cell types that comprise these pathways, we used high-throughput single-cell RNA sequencing (scRNAseq). From ∼24,000 single-cell transcriptomes, we identified 19 cell types with molecular markers for each and used histological methods to localize each type. We then performed similar analyses on four organisms used for experimental studies of IOP dynamics and glaucoma: cynomolgus macaque (Macaca fascicularis), rhesus macaque (Macaca mulatta), pig (Sus scrofa), and mouse (Mus musculus). Many human cell types had counterparts in these models, but differences in cell types and gene expression were evident. Finally, we identified the cell types that express genes implicated in glaucoma in all five species. Together, our results provide foundations for investigating the pathogenesis of glaucoma and for using model systems to assess mechanisms and potential interventions.
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Affiliation(s)
- Tavé van Zyl
- Department of Ophthalmology, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA 02114;
- Center for Brain Science, Harvard University, Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
| | - Wenjun Yan
- Center for Brain Science, Harvard University, Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
| | - Alexi McAdams
- Department of Ophthalmology, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA 02114
- Center for Brain Science, Harvard University, Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
| | - Yi-Rong Peng
- Center for Brain Science, Harvard University, Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
| | - Karthik Shekhar
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02142
- Koch Institute of Integrative Cancer Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Aviv Regev
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02142
- Koch Institute of Integrative Cancer Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
- Klarman Cell Observatory, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142
| | - Dejan Juric
- Department of Medicine, Harvard Medical School and Massachusetts General Hospital Cancer Center, Boston, MA 02114
| | - Joshua R Sanes
- Center for Brain Science, Harvard University, Cambridge, MA 02138;
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138
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Akula M, Taiyab A, Deschamps P, Yee S, Ball AK, Williams T, West-Mays JA. AP-2β is required for formation of the murine trabecular meshwork and Schlemm's canal. Exp Eye Res 2020; 195:108042. [PMID: 32353428 DOI: 10.1016/j.exer.2020.108042] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/02/2020] [Accepted: 04/22/2020] [Indexed: 12/21/2022]
Abstract
Previously, we have shown that Tfap2b, the gene encoding transcription factor AP-2β, is needed for normal mouse eye development. Specifically, targeted loss of Tfap2b in neural crest cells (NCCs)1 and their derivatives, particularly the periocular mesenchyme (POM), resulted in anterior segment defects affecting the cornea and angle tissue. These defects were further associated with an increase in intraocular pressure (IOP). The present study investigates the underlying changes in embryonic and postnatal POM cell development and differentiation caused by loss of AP-2β in the NCCs, particularly in the structures that control aqueous outflow, using Wnt1Cre+/-; Tfap2b-/lox; tdTomatolox/+ mice (AP-2β neural crest cell knockout or AP-2β NCC KO). Toluidine blue-stained sections and ultrathin sections stained with uranyl acetate and lead citrate were used to assess morphology and ultrastructure, respectively. Immunohistochemistry of KO and control eyes was performed at embryonic day (E) 15.5, E18.5, postnatal day (P) 1, P7 and P14 using phospho-histone H3 (PH3), α-smooth muscle actin (α-SMA), myocilin and endomucin antibodies, as well as a TUNEL assay. Conditional deletion of AP-2β in the NCC-derived POM resulted in defects that appeared during both embryogenesis and postnatal stages. Fate mapping of the knockout cells in the mutants revealed that the POM migrated appropriately into the eye during embryogenesis. However, during postnatal stages a significant reduction in POM proliferation in the angle region was observed in the mutants compared to controls. This was accompanied by a lack of expression of appropriate trabecular meshwork and Schlemm's canal markers. This is the first study to show that AP-2β is required for development and differentiation of the trabecular meshwork and Schlemm's canal. Together, these defects likely contributed to the elevated intraocular pressure (IOP) previously reported in the AP-2β NCC KO mice.
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Affiliation(s)
- Monica Akula
- McMaster University, Health Sciences Centre, 1280 Main St. W, L8S 4L8, Hamilton, ON, Canada
| | - Aftab Taiyab
- McMaster University, Health Sciences Centre, 1280 Main St. W, L8S 4L8, Hamilton, ON, Canada
| | - Paula Deschamps
- McMaster University, Health Sciences Centre, 1280 Main St. W, L8S 4L8, Hamilton, ON, Canada
| | - Shannin Yee
- McMaster University, Health Sciences Centre, 1280 Main St. W, L8S 4L8, Hamilton, ON, Canada
| | - Alexander K Ball
- McMaster University, Health Sciences Centre, 1280 Main St. W, L8S 4L8, Hamilton, ON, Canada
| | - Trevor Williams
- University of Colorado, Craniofacial Biology, Mail Stop 8120, RC1-S, Rm L18 111, 12801 E. 17th Ave, Aurora, CO, 80045, USA
| | - Judith A West-Mays
- McMaster University, Health Sciences Centre, 1280 Main St. W, L8S 4L8, Hamilton, ON, Canada.
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Papaefthymiou A, Doulberis M, Katsinelos P, Liatsos C, Polyzos SA, Kotronis G, Papanikolaou K, Kountouras J. Impact of nitric oxide's bidirectional role on glaucoma: focus onHelicobacter pylori–related nitrosative stress. Ann N Y Acad Sci 2020; 1465:10-28. [DOI: 10.1111/nyas.14253] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/07/2019] [Accepted: 09/17/2019] [Indexed: 12/12/2022]
Affiliation(s)
| | - Michael Doulberis
- Department of Gastroenterology and HepatologyUniversity of Zurich Zurich Switzerland
- Department of Internal Medicine, Second Medical Clinic, Ippokration HospitalAristotle University of Thessaloniki Thessaloniki Macedonia Greece
| | - Panagiotis Katsinelos
- Department of Internal Medicine, Second Medical Clinic, Ippokration HospitalAristotle University of Thessaloniki Thessaloniki Macedonia Greece
| | - Christos Liatsos
- Department of Gastroenterology401 General Military Hospital of Athens Athens Greece
| | - Stergios A. Polyzos
- Department of Internal Medicine, Second Medical Clinic, Ippokration HospitalAristotle University of Thessaloniki Thessaloniki Macedonia Greece
- First Department of Pharmacology, School of MedicineAristotle University of Thessaloniki Thessaloniki Macedonia Greece
| | - Georgios Kotronis
- Department of Internal MedicineAgios Pavlos General Hospital Thessaloniki Macedonia Greece
| | - Katerina Papanikolaou
- Department of Internal Medicine, Second Medical Clinic, Ippokration HospitalAristotle University of Thessaloniki Thessaloniki Macedonia Greece
| | - Jannis Kountouras
- Department of Internal Medicine, Second Medical Clinic, Ippokration HospitalAristotle University of Thessaloniki Thessaloniki Macedonia Greece
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Chen Y, Gao J, Li L, Sellitto C, Mathias RT, Donaldson PJ, White TW. The Ciliary Muscle and Zonules of Zinn Modulate Lens Intracellular Hydrostatic Pressure Through Transient Receptor Potential Vanilloid Channels. Invest Ophthalmol Vis Sci 2020; 60:4416-4424. [PMID: 31639828 PMCID: PMC6808041 DOI: 10.1167/iovs.19-27794] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose Lenses have an intracellular hydrostatic pressure gradient to drive fluid from central fiber cells to surface epithelial cells. Pressure is regulated by a feedback control system that relies on transient receptor potential vanilloid (TRPV)1 and TRPV4 channels. The ciliary muscle transmits tension to the lens through the zonules of Zinn. Here, we have examined if ciliary muscle tension influenced the lens intracellular hydrostatic pressure gradient. Methods We measured the ciliary body position and intracellular hydrostatic pressures in mouse lenses while pharmacologically causing relaxation or contraction of the ciliary muscle. We also used inhibitors of TRPV1 and TRPV4, in addition to phosphoinositide 3-kinase (PI3K) p110α knockout mice and immunostaining of phosphorylated protein kinase B (Akt), to determine how changes in ciliary muscle tension resulted in altered hydrostatic pressure. Results Ciliary muscle relaxation increased the distance between the ciliary body and the lens and caused a decrease in intracellular hydrostatic pressure that was dependent on intact zonules and could be blocked by inhibition of TRPV4. Ciliary contraction moved the ciliary body toward the lens and caused an increase in intracellular hydrostatic pressure and Akt phosphorylation that required intact zonules and was blocked by either inhibition of TRPV1 or genetic deletion of the p110α catalytic subunit of PI3K. Conclusions These results show that the hydrostatic pressure gradient within the lens was influenced by the tension exerted on the lens by the ciliary muscle through the zonules of Zinn. Modulation of the gradient of intracellular hydrostatic pressure in the lens could alter the water content, and the gradient of refractive index.
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Affiliation(s)
- Yadi Chen
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Junyuan Gao
- Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
| | - Leping Li
- Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
| | - Caterina Sellitto
- Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
| | - Richard T Mathias
- Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Thomas W White
- Renaissance Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York, United States
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Ficarrotta KR, Passaglia CL. Intracranial pressure modulates aqueous humour dynamics of the eye. J Physiol 2020; 598:403-413. [PMID: 31769030 DOI: 10.1113/jp278768] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/22/2019] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS An elevation in intracranial pressure (ICP) lowers conventional outflow facility (increases aqueous outflow resistance) of rat eyes. The reduction in outflow facility correlates with an increase in intraocular pressure (IOP). The effect of ICP elevation on outflow facility and IOP is blocked by TTX. The results indicate that aqueous humour dynamics is modulated by ICP-driven neural feedback from the brain. This feedback mechanism may act to stabilize translaminar pressure across the optic nerve head and may provide a new avenue for glaucoma therapy. ABSTRACT While intraocular pressure (IOP) is a well-known risk factor for glaucoma, intracranial pressure (ICP) is attracting heightened interest because of its influence on optic nerve head biomechanics. Studies have shown that ICP can have marked impacts on posterior eye health by modifying the translaminar pressure gradient across the optic nerve. There is also growing evidence that IOP and ICP may be interconnected, although the mechanism of their putative interaction is unknown. We sought to test the hypothesis that ICP modulates IOP by altering aqueous humour dynamics. The anterior chamber and lateral ventricle of anaesthetized Brown-Norway rats were cannulated with fine-gauge needles connected to a programmable pump and saline reservoir, respectively. ICP was manipulated by varying reservoir height, and eye outflow facility (C) was determined from the pump flow rate required to hold IOP at different levels. C was 22 ± 4 nl/min/mmHg at resting ICP and 13 ± 3 nl/min/mmHg when ICP was raised 15 mmHg, a reduction of 41 ± 13% (n = 18). The decrease in outflow facility was independent of blood pressure, reversible, scaled with ICP elevation and correlated with increases in resting IOP. It was physiological in origin because C returned to baseline values after the rats were killed and corneal application of TTX though ICP remained elevated. These results indicate that a neural feedback mechanism driven by ICP regulates conventional outflow facility in rats. The mechanism may protect the eye from translaminar pressure swings and may offer a new target for glaucoma treatment.
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Affiliation(s)
- Kayla R Ficarrotta
- Medical Engineering Department, University of South Florida, Tampa, FL, 33620, USA
| | - Christopher L Passaglia
- Medical Engineering Department, University of South Florida, Tampa, FL, 33620, USA.,Ophthalmology Department, University of South Florida, Tampa, FL, 33620, USA
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Aggarwala KRG. Ocular Accommodation, Intraocular Pressure, Development of Myopia and Glaucoma: Role of Ciliary Muscle, Choroid and Metabolism. MEDICAL HYPOTHESIS, DISCOVERY & INNOVATION OPHTHALMOLOGY JOURNAL 2020; 9:66-70. [PMID: 31976346 PMCID: PMC6969557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ocular accommodation is not just a mechanism for altering curvature of the crystalline lens of the eye, it also enables aqueous humor outflow through the trabecular meshwork, influencing intraocular pressure (IOP). Long term stress on the ciliary muscle from sustained near focusing may initiate myopic eye growth in children and primary open angle glaucoma in presbyopic adults. Multi-factorial studies of ocular accommodation that include measures of IOP, ciliary muscle morphology, anterior chamber depth and assessment of nutritional intake and metabolic markers may elucidate etiology and novel strategies for management of both myopia and chronic glaucoma. Anatomy of the ciliary fibers from anterior insertion in the fluid drainage pathway to their posterior consanguinity with the vascular choroid, alters ocular parameters such as micro-fluctuations of accommodation and pulsatile ocular blood flow that are driven by cardiac contractions conveyed by carotid arteries. Stretching of the choroid has consequences for thinning of the peripheral retina, sclera and lamina cribrosa with potential to induce retinal tears and optic nerve cupping. Early metabolic interventions may lead to prevention or reduced severity of myopia and glaucoma. Finally, it might improve quality of life of patients and decrease disability from visual impairment and blindness.
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Boote C, Sigal IA, Grytz R, Hua Y, Nguyen TD, Girard MJA. Scleral structure and biomechanics. Prog Retin Eye Res 2019; 74:100773. [PMID: 31412277 DOI: 10.1016/j.preteyeres.2019.100773] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 08/07/2019] [Accepted: 08/08/2019] [Indexed: 12/18/2022]
Abstract
As the eye's main load-bearing connective tissue, the sclera is centrally important to vision. In addition to cooperatively maintaining refractive status with the cornea, the sclera must also provide stable mechanical support to vulnerable internal ocular structures such as the retina and optic nerve head. Moreover, it must achieve this under complex, dynamic loading conditions imposed by eye movements and fluid pressures. Recent years have seen significant advances in our knowledge of scleral biomechanics, its modulation with ageing and disease, and their relationship to the hierarchical structure of the collagen-rich scleral extracellular matrix (ECM) and its resident cells. This review focuses on notable recent structural and biomechanical studies, setting their findings in the context of the wider scleral literature. It reviews recent progress in the development of scattering and bioimaging methods to resolve scleral ECM structure at multiple scales. In vivo and ex vivo experimental methods to characterise scleral biomechanics are explored, along with computational techniques that combine structural and biomechanical data to simulate ocular behaviour and extract tissue material properties. Studies into alterations of scleral structure and biomechanics in myopia and glaucoma are presented, and their results reconciled with associated findings on changes in the ageing eye. Finally, new developments in scleral surgery and emerging minimally invasive therapies are highlighted that could offer new hope in the fight against escalating scleral-related vision disorder worldwide.
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Affiliation(s)
- Craig Boote
- Structural Biophysics Research Group, School of Optometry & Vision Sciences, Cardiff University, UK; Ophthalmic Engineering & Innovation Laboratory (OEIL), Department of Biomedical Engineering, National University of Singapore, Singapore; Newcastle Research & Innovation Institute Singapore (NewRIIS), Singapore.
| | - Ian A Sigal
- Laboratory of Ocular Biomechanics, Department of Ophthalmology, University of Pittsburgh, USA
| | - Rafael Grytz
- Department of Ophthalmology & Visual Sciences, University of Alabama at Birmingham, USA
| | - Yi Hua
- Laboratory of Ocular Biomechanics, Department of Ophthalmology, University of Pittsburgh, USA
| | - Thao D Nguyen
- Department of Mechanical Engineering, Johns Hopkins University, USA
| | - Michael J A Girard
- Ophthalmic Engineering & Innovation Laboratory (OEIL), Department of Biomedical Engineering, National University of Singapore, Singapore; Singapore Eye Research Institute (SERI), Singapore National Eye Centre, Singapore
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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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Reina-Torres E, Bertrand JA, O'Callaghan J, Sherwood JM, Humphries P, Overby DR. Reduced humidity experienced by mice in vivo coincides with reduced outflow facility measured ex vivo. Exp Eye Res 2019; 186:107745. [PMID: 31351057 DOI: 10.1016/j.exer.2019.107745] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/05/2019] [Accepted: 07/23/2019] [Indexed: 11/16/2022]
Abstract
Mice are routinely used to study aqueous humour dynamics. However, physical factors such as temperature and hydration affect outflow facility in enucleated eyes. This retrospective study examined whether differences in temperature and relative humidity experienced by living mice within their housing environment in vivo coincide with differences in outflow facility measured ex vivo. Facility data and environmental records were collected for one enucleated eye from 116 mice (C57BL/6J males, 9-15 weeks old) at two institutions. Outflow facility was reduced when relative humidity was below the lower limit of 45% recommended by the UK Code of Practice, but there was no detectable effect of temperature on outflow facility. Even when accounting for effects of humidity, there were differences in outflow facility measured between institutions and between individual researchers at the same institution. These data indicate that humidity, as well as additional environmental factors experienced by living mice within their housing environment, may significantly affect outflow facility measured ex vivo.
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Affiliation(s)
- Ester Reina-Torres
- Department of Bioengineering, Imperial College London, London, United Kingdom; Ocular Genetics Unit, Smurfit Institute of Genetics, University of Dublin, Trinity College, Dublin, Ireland
| | - Jacques A Bertrand
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Jeffrey O'Callaghan
- Ocular Genetics Unit, Smurfit Institute of Genetics, University of Dublin, Trinity College, Dublin, Ireland
| | - Joseph M Sherwood
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Peter Humphries
- Ocular Genetics Unit, Smurfit Institute of Genetics, University of Dublin, Trinity College, Dublin, Ireland
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, United Kingdom.
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Kaufman PL, Lütjen Drecoll E, Croft MA. Presbyopia and Glaucoma: Two Diseases, One Pathophysiology? The 2017 Friedenwald Lecture. Invest Ophthalmol Vis Sci 2019; 60:1801-1812. [PMID: 31038661 PMCID: PMC6540935 DOI: 10.1167/iovs.19-26899] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Paul L. Kaufman
- Department of Ophthalmology and Visual Sciences, Wisconsin National Primate Research Center, McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | | | - Mary Ann Croft
- Department of Ophthalmology and Visual Sciences, Wisconsin National Primate Research Center, McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, Wisconsin, United States
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Oliver JA, Ricketts SL, Kuehn MH, Mellersh CS. Primary closed angle glaucoma in the Basset Hound: Genetic investigations using genome-wide association and RNA sequencing strategies. Mol Vis 2019; 25:93-105. [PMID: 30820145 PMCID: PMC6377385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 02/06/2019] [Indexed: 11/18/2022] Open
Abstract
Purpose To investigate the genetic basis of primary closed angle glaucoma (PCAG) in European Basset Hounds using genome-wide association and RNA sequencing strategies. Methods DNA samples from 119 European Basset Hounds were genotyped on the 170 K SNP CanineHD BeadChip array (Illumina) comprising 37 with normal iridocorneal angles (controls), 57 with pectinate ligament abnormality (PLA cases), and 25 with PCAG (PCAG cases). Genome-wide association studies (GWASs) of the PLA and PCAG cases were conducted. Whole transcriptome sequences of iridocorneal angle tissues from five Basset Hounds with PCAG were compared with those from four dogs with normal eyes to investigate differences in gene expression between the affected and unaffected eyes in GWAS-associated loci. A variant in NEB, previously reported to be associated with PCAG in American Basset Hounds, was genotyped in cohorts of European Basset Hounds and non-Basset Hounds. Results The GWASs revealed 1.4 and 0.2 Mb regions, on chromosomes 24 and 37, respectively, that are statistically associated with PCAG. The former locus has previously been associated with glaucoma in humans. Whole transcriptome analysis revealed differential gene expression of eight genes within these two loci. The NEB variant was not associated with PLA or PCAG in this set of European Basset Hounds. Conclusions We identified two novel loci for canine PCAG. Further investigation is required to elucidate candidate variants that underlie canine PCAG.
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Affiliation(s)
- James A.C. Oliver
- Canine Genetics Research Group, Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, United Kingdom
| | - Sally L. Ricketts
- Canine Genetics Research Group, Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, United Kingdom
| | - Markus H. Kuehn
- The University of Iowa, Department of Ophthalmology and Visual Sciences, Iowa City, IO
| | - Cathryn S. Mellersh
- Canine Genetics Research Group, Kennel Club Genetics Centre, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, United Kingdom
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Childhood Lensectomy Is Associated with Static and Dynamic Reduction in Schlemm Canal Size. Ophthalmology 2019; 126:233-241. [DOI: 10.1016/j.ophtha.2018.08.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 08/13/2018] [Accepted: 08/24/2018] [Indexed: 11/22/2022] Open
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Park S, Kang S, Lim J, Park E, Nam T, Jeong S, Seo K. Effects of prostaglandin-mediated and cholinergic-mediated miosis on morphology of the ciliary cleft region in dogs. Am J Vet Res 2018; 79:980-985. [DOI: 10.2460/ajvr.79.9.980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Dimensions of the ciliary muscles of Brücke, Müller and Iwanoff and their associations with axial length and glaucoma. Graefes Arch Clin Exp Ophthalmol 2018; 256:2165-2171. [DOI: 10.1007/s00417-018-4085-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 07/10/2018] [Accepted: 07/26/2018] [Indexed: 10/28/2022] Open
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44
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Xin C, Song S, Johnstone M, Wang N, Wang RK. Quantification of Pulse-Dependent Trabecular Meshwork Motion in Normal Humans Using Phase-Sensitive OCT. Invest Ophthalmol Vis Sci 2018; 59:3675-3681. [PMID: 30029254 PMCID: PMC6054426 DOI: 10.1167/iovs.17-23579] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 05/30/2018] [Indexed: 12/23/2022] Open
Abstract
Purpose The purpose of this study was to characterize the pulsatile motion of trabecular meshwork (TM) in normal subjects and demonstrate its changes in accommodation with phase-sensitive optical coherence tomography (PhS-OCT). Methods A new PhS-OCT laboratory prototype was designed to measure pulsatile TM motion in 13 healthy humans. Two sets of images were captured in 10 subjects, first with best corrective refraction and the other with an additional 3.0 diopters of accommodation. In each image, both maximum velocity (MV) and cumulative displacement (CD) in two selected regions of TM, the internal (IMV and ICD) and external (EMV and ECD) region, were measured. Results For all parameters the intraclass correlation coefficient was >0.75. Neither MV nor CD was significantly different between eyes in individual subjects (PIMV = 0.967, PEMV = 0.391, PICD = 0.603, PECD = 0.482). In 26 eyes, with best corrective refraction, the EMV was higher than the IMV (23.9 ± 9.8 vs. 18.9 ± 8.08 μm/s; P = 0.0001), as was the ECD compared with the ICD (0.340 ±0.125 vs. 0.264 ± 0.111 μm; P = 0.000004). With accommodation, MV and CD significantly increased (PIMV = 0.0003, PEMV = 0.0003, PICD = 0.019, and PECD = 0.007), whereas MV and CD in the external region were still larger than those in the internal area (PEMV vs. IMV = 0.009, PECD vs. ICD = 0.023). Conclusions This study demonstrates the differences in TM motion between the internal and external regions of TM and displays its change with accommodation. The findings and good reproducibility suggest PhS-OCT helps to understand TM function in regulation of IOP, and, with further refinements, it may be useful in clinical management of glaucoma.
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Affiliation(s)
- Chen Xin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Murray Johnstone
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Ningli Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
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Daniel MC, Dubis AM, Quartilho A, Al-Hayouti H, Khaw SPT, Theodorou M, Dahlmann-Noor A. Dynamic Changes in Schlemm Canal and Iridocorneal Angle Morphology During Accommodation in Children With Healthy Eyes: A Cross-Sectional Cohort Study. Invest Ophthalmol Vis Sci 2018; 59:3497-3502. [PMID: 30025073 DOI: 10.1167/iovs.17-23189] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to explore changes in Schlemm canal (SC), trabecular meshwork (TM), and iridocorneal angle (ICA) morphology during accommodative effort in children and young adults. Methods We acquired anterior segment optical coherence tomography images (AS-OCT) of the ICA and ciliary muscle (CM) of both eyes of 50 children age 4 to 16 years with healthy eyes, at two levels of accommodation: 2.5 and 15 diopters (D). Semiautomated nasal ICA measurements were as follows: angle opening distance at 500/750 μm (AOD-500, -750), trabecular iris space area at 500/750 μm (TISA-500, -750), and trabecular iris angle at 500/750 μm (TIA-500, -750). Manual measurements were as follows: anteroposterior and radial SC diameter (SC-APD, SC-RD), cross-sectional area of SC (SC-CSA) and TM height (TMH), TM length (TML), and TM density (TMD). CM width was measured at 1, 2, and 3 mm from the scleral spur (CM-1, CM-2, CM-3). For each parameter, a three-level random-effects model was fitted to estimate differences between the two levels of accommodation. Results With accommodative effort, SC diameters and CSA increase significantly, as do TM length and iridocorneal angle parameters. With increasing age, SC dimensions reduce. Angle parameters are smaller in eyes with greater spherical equivalent (hypermetropia). Conclusions AS-OCT can be used to visualize dynamic morphologic changes in outflow structures with physiologic accommodation. The increase in SC dimensions with accommodative effort may contribute to the regulation of IOP in children.
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Affiliation(s)
- Moritz Claudius Daniel
- National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and University College London Institute of Ophthalmology, London, United Kingdom.,Eye Center, Medical Center, University of Freiburg Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Adam M Dubis
- National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and University College London Institute of Ophthalmology, London, United Kingdom
| | - Ana Quartilho
- National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and University College London Institute of Ophthalmology, London, United Kingdom.,Comprehensive Clinical Trials Unit, University College London, London, United Kingdom
| | - Huda Al-Hayouti
- National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and University College London Institute of Ophthalmology, London, United Kingdom
| | - Sir Peng Tee Khaw
- National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and University College London Institute of Ophthalmology, London, United Kingdom
| | - Maria Theodorou
- National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and University College London Institute of Ophthalmology, London, United Kingdom
| | - Annegret Dahlmann-Noor
- National Institute for Health Research Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and University College London Institute of Ophthalmology, London, United Kingdom
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46
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TAVARES-SILVA M, FERREIRA D, CARDOSO S, RAIMUNDO AR, BARBOSA-BREDA J, LEITE-MOREIRA A, ROCHA-SOUSA A. Modulation of Iris Sphincter and Ciliary Muscles by Urocortin 2. Physiol Res 2018. [DOI: 10.33549/physiolres.933646] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Urocortin 2 (UCN2) is a peptide related to corticotropin-releasing factor, capable of activating CRF-R2. Among its multisystemic effects, it has actions in all 3 muscle subtypes. This study’s aim was to determine its potential role in two of the intrinsic eye muscle kinetics. Strips of iris sphincter (rabbit) and ciliary (bovine) muscles were dissected and mounted in isometric force-transducer systems filled with aerated-solutions. Contraction was elicited using carbachol (10-6 M for iris sphincter, 10-5 M for ciliary muscle), prior adding to all testing substances. UCN2 induced relaxation in iris sphincter muscle, being the effect maximal at 10-7 M concentrations (-12.2 % variation vs. control). This effect was abolished with incubation of indomethacin, antisauvagine-30, chelerytrine and SQ22536, but preserved with L-nitro-L-arginine. In carbachol pre-stimulated ciliary muscle, UCN2 (10-5 M) enhanced contraction (maximal effect of 18.2 % increase vs. control). UCN2 is a new modulator of iris sphincter relaxation, dependent of CRF-R2 activation, synthesis of prostaglandins (COX pathway) and both adenylate cyclase and PKC signaling pathways, but independent of nitric oxide production. Regarding ciliary muscle, UCN2 enhances carbachol-induced contraction, in higher doses.
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Affiliation(s)
| | | | | | | | | | | | - A. ROCHA-SOUSA
- Department of Surgery and Physiology, Faculty of Medicine, University of Porto, Portugal
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47
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Wareham LK, Buys ES, Sappington RM. The nitric oxide-guanylate cyclase pathway and glaucoma. Nitric Oxide 2018; 77:75-87. [PMID: 29723581 DOI: 10.1016/j.niox.2018.04.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/18/2018] [Accepted: 04/23/2018] [Indexed: 01/12/2023]
Abstract
Glaucoma is a prevalent optic neuropathy characterized by the progressive dysfunction and loss of retinal ganglion cells (RGCs) and their optic nerve axons, which leads to irreversible visual field loss. Multiple risk factors for the disease have been identified, but elevated intraocular pressure (IOP) remains the primary risk factor amenable to treatment. Reducing IOP however does not always prevent glaucomatous neurodegeneration, and many patients progress with the disease despite having IOP in the normal range. There is increasing evidence that nitric oxide (NO) is a direct regulator of IOP and that dysfunction of the NO-Guanylate Cyclase (GC) pathway is associated with glaucoma incidence. NO has shown promise as a novel therapeutic with targeted effects that: 1) lower IOP; 2) increase ocular blood flow; and 3) confer neuroprotection. The various effects of NO in the eye appear to be mediated through the activation of the GC- guanosine 3:5'-cyclic monophosphate (cGMP) pathway and its effect on downstream targets, such as protein kinases and Ca2+ channels. Although NO-donor compounds are promising as therapeutics for IOP regulation, they may not be ideal to harness the neuroprotective potential of NO signaling. Here we review evidence that supports direct targeting of GC as a novel pleiotrophic treatment for the disease, without the need for direct NO application. The identification and targeting of other factors that contribute to glaucoma would be beneficial to patients, particularly those that do not respond well to IOP-dependent interventions.
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Affiliation(s)
- Lauren K Wareham
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | | | - Rebecca M Sappington
- Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.
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Wang K, Li G, Read AT, Navarro I, Mitra AK, Stamer WD, Sulchek T, Ethier CR. The relationship between outflow resistance and trabecular meshwork stiffness in mice. Sci Rep 2018; 8:5848. [PMID: 29643342 PMCID: PMC5895808 DOI: 10.1038/s41598-018-24165-w] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 03/26/2018] [Indexed: 11/25/2022] Open
Abstract
It has been suggested that common mechanisms may underlie the pathogenesis of primary open-angle glaucoma (POAG) and steroid-induced glaucoma (SIG). The biomechanical properties (stiffness) of the trabecular meshwork (TM) have been shown to differ between POAG patients and unaffected individuals. While features such as ocular hypertension and increased outflow resistance in POAG and SIG have been replicated in mouse models, whether changes of TM stiffness contributes to altered IOP homeostasis remains unknown. We found that outer TM was stiffer than the inner TM and, there was a significant positive correlation between outflow resistance and TM stiffness in mice where conditions are well controlled. This suggests that TM stiffness is intimately involved in establishing outflow resistance, motivating further studies to investigate factors underlying TM biomechanical property regulation. Such factors may play a role in the pathophysiology of ocular hypertension. Additionally, this finding may imply that manipulating TM may be a promising approach to restore normal outflow dynamics in glaucoma. Further, novel technologies are being developed to measure ocular tissue stiffness in situ. Thus, the changes of TM stiffness might be a surrogate marker to help in diagnosing altered conventional outflow pathway function if those technologies could be adapted to TM.
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Affiliation(s)
- Ke Wang
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, 30332, United States of America
| | - Guorong Li
- Department of Ophthalmology, Duke University, Durham, North Carolina, 27708, United States of America
| | - A Thomas Read
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, 30332, United States of America
| | - Iris Navarro
- Department of Ophthalmology, Duke University, Durham, North Carolina, 27708, United States of America
| | - Ashim K Mitra
- School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, 64110, United States of America
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, North Carolina, 27708, United States of America
| | - Todd Sulchek
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, United States of America
| | - C Ross Ethier
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, 30332, United States of America. .,George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, United States of America.
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McDonnell F, Dismuke WM, Overby DR, Stamer WD. Pharmacological regulation of outflow resistance distal to Schlemm's canal. Am J Physiol Cell Physiol 2018; 315:C44-C51. [PMID: 29631366 DOI: 10.1152/ajpcell.00024.2018] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The trabecular meshwork (TM) and Schlemm's canal generate the majority of outflow resistance; however, the distal regions of the conventional outflow pathway account for 25-50% of total resistance. Sections of distal vessels are surrounded by α-smooth muscle actin-containing cells, indicating that they may be vasoregulated. This study examined the effect of a potent vasodilator, nitric oxide (NO), and its physiological antagonist, endothelin-1 (ET-1), on the regulation of outflow resistance in the distal regions of the conventional outflow pathway. Using a physiological model of the conventional outflow pathway, human and porcine anterior segments were perfused in organ culture under constant flow conditions, while intrachamber pressure was continually monitored. For porcine anterior segments, a stable baseline outflow facility with TM intact was first achieved before anterior segments were removed and a trabeculotomy was performed. For human anterior segments, a trabeculotomy was immediately performed. In human anterior segments, 100 nM ET-1 significantly decreased distal outflow facility from 0.49 ± 0.26 to 0.31 ± 0.18 (mean ± SD) µl·min-1·mmHg, P < 0.01. Perfusion with 100 µM diethylenetriamine-NO in the presence of 1 nM ET-1 immediately reversed ET-1 effects, significantly increasing distal outflow facility to 0.54 ± 0.35 µl·min-1·mmHg, P = 0.01. Similar results were obtained in porcine anterior segment experiments. Therefore, data show a dynamic range of resistance generation by distal vessels in both the human and the porcine conventional outflow pathways. Interestingly, maximal contraction of vessels in the distal outflow tract of trabeculotomized eyes generated resistance very near physiological levels for both species having an intact TM.
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Affiliation(s)
- Fiona McDonnell
- Department of Ophthalmology, Duke University , Durham, North Carolina
| | - W Michael Dismuke
- Department of Ophthalmology, Duke University , Durham, North Carolina
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London , London , United Kingdom
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University , Durham, North Carolina.,Department of Biomedical Engineering, Duke University , Durham, North Carolina
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50
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Abstract
Mice and rats are being increasingly used in glaucoma research and much useful data have been generated from them. One aspect of using these animals for this purpose involves assessment of aqueous humor dynamics. Several techniques have been described in the literature for the determination of one or more of these parameters in rodents, in both living animals and eyes perfused ex vivo. Here, we describe the practical details for a technique for the determination of all principal parameters of aqueous humor dynamics (intraocular pressure (IOP), aqueous humor formation rate (Fin), uveoscleral outflow rate (Fu), aqueous outflow facility (C), and episcleral venous pressure (Pe)) in the living rat and mouse eye, in a single experimental session.
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