1
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Karnam S, Maurya S, Ng E, Choudhary A, Thobani A, Flanagan JG, Gronert K. Dysregulation of neuroprotective lipoxin pathway in astrocytes in response to cytokines and ocular hypertension. Acta Neuropathol Commun 2024; 12:58. [PMID: 38610040 PMCID: PMC11010376 DOI: 10.1186/s40478-024-01767-2] [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: 09/12/2023] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Glaucoma leads to vision loss due to retinal ganglion cell death. Astrocyte reactivity contributes to neurodegeneration. Our recent study found that lipoxin B4 (LXB4), produced by retinal astrocytes, has direct neuroprotective actions on retinal ganglion cells. In this study, we aimed to investigate how the autacoid LXB4 influences astrocyte reactivity in the retina under inflammatory cytokine-induced activation and during ocular hypertension. The protective activity of LXB4 was investigated in vivo using the mouse silicone-oil model of chronic ocular hypertension. By employing a range of analytical techniques, including bulk RNA-seq, RNAscope in-situ hybridization, qPCR, and lipidomic analyses, we discovered the formation of lipoxins and expression of the lipoxin pathway in rodents (including the retina and optic nerve), primates (optic nerve), and human brain astrocytes, indicating the presence of this neuroprotective pathway across various species. Findings in the mouse retina identified significant dysregulation of the lipoxin pathway in response to chronic ocular hypertension, leading to an increase in 5-lipoxygenase (5-LOX) activity and a decrease in 15-LOX activity. This dysregulation was coincident with a marked upregulation of astrocyte reactivity. Reactive human brain astrocytes also showed a significant increase in 5-LOX. Treatment with LXB4 amplified the lipoxin biosynthetic pathway by restoring and amplifying the generation of another member of the lipoxin family, LXA4, and mitigated astrocyte reactivity in mouse retinas and human brain astrocytes. In conclusion, the lipoxin pathway is functionally expressed in rodents, primates, and human astrocytes, and is a resident neuroprotective pathway that is downregulated in reactive astrocytes. Novel cellular targets for LXB4's neuroprotective action are inhibition of astrocyte reactivity and restoration of lipoxin generation. Amplifying the lipoxin pathway is a potential target to disrupt or prevent astrocyte reactivity in neurodegenerative diseases, including retinal ganglion cell death in glaucoma.
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Affiliation(s)
- Shruthi Karnam
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, CA, USA
| | - Shubham Maurya
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, CA, USA
| | - Elainna Ng
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, CA, USA
| | - Amodini Choudhary
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, CA, USA
| | - Arzin Thobani
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, CA, USA
| | - John G Flanagan
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, CA, USA.
| | - Karsten Gronert
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, CA, USA.
- Infectious Disease and Immunity Program, Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, CA, USA.
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2
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Maurya S, Lin M, Karnam S, Singh T, Kumar M, Ward E, Flanagan JG, Gronert K. Regulation of Diseases-Associated Microglia in the Optic Nerve by Lipoxin B 4 and Ocular Hypertension. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.18.585452. [PMID: 38562864 PMCID: PMC10983965 DOI: 10.1101/2024.03.18.585452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Background The resident astrocyte-retinal ganglion cell (RGC) lipoxin circuit is impaired during retinal stress, which includes ocular hypertension-induced neuropathy. Lipoxin B4 produced by homeostatic astrocytes directly acts on RGCs to increase survival and function in ocular hypertension-induced neuropathy. RGC death in the retina and axonal degeneration in the optic nerve are driven by the complex interactions between microglia and macroglia. Whether LXB4 neuroprotective actions include regulation of other cell types in the retina and/or optic nerve is an important knowledge gap. Methods Cellular targets and signaling of LXB4 in the retina were defined by single-cell RNA sequencing. Retinal neurodegeneration was induced by injecting silicone oil into the anterior chamber of the mouse eyes, which induced sustained and stable ocular hypertension. Morphological characterization of microglia populations in the retina and optic nerve was established by MorphOMICs and pseudotime trajectory analyses. The pathways and mechanisms of action of LXB4 in the optic nerve were investigated using bulk RNA sequencing. Transcriptomics data was validated by qPCR and immunohistochemistry. Differences between experimental groups was assessed by Student's t-test and one-way ANOVA. Results Single-cell transcriptomics identified microglia as a primary target for LXB4 in the healthy retina. LXB4 downregulated genes that drive microglia environmental sensing and reactivity responses. Analysis of microglial function revealed that ocular hypertension induced distinct, temporally defined, and dynamic phenotypes in the retina and, unexpectedly, in the distal myelinated optic nerve. Microglial expression of CD74, a marker of disease-associated microglia in the brain, was only induced in a unique population of optic nerve microglia, but not in the retina. Genetic deletion of lipoxin formation correlated with the presence of a CD74 optic nerve microglia population in normotensive eyes, while LXB4 treatment during ocular hypertension shifted optic nerve microglia toward a homeostatic morphology and non-reactive state and downregulated the expression of CD74. Furthermore, we identified a correlation between CD74 and phospho-phosphoinositide 3-kinases (p-PI3K) expression levels in the optic nerve, which was reduced by LXB4 treatment. Conclusion We identified early and dynamic changes in the microglia functional phenotype, reactivity, and induction of a unique CD74 microglia population in the distal optic nerve as key features of ocular hypertension-induced neurodegeneration. Our findings establish microglia regulation as a novel LXB4 target in the retina and optic nerve. LXB4 maintenance of a homeostatic optic nerve microglia phenotype and inhibition of a disease-associated phenotype are potential neuroprotective mechanisms for the resident LXB4 pathway.
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Affiliation(s)
- Shubham Maurya
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, United States
| | - Maggie Lin
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, United States
| | - Shruthi Karnam
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, United States
| | - Tanirika Singh
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, United States
| | - Matangi Kumar
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, United States
- Vision Science Program, University of California Berkeley, CA, United States
| | - Emily Ward
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, United States
- Vision Science Program, University of California Berkeley, CA, United States
| | - John G Flanagan
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, United States
- Vision Science Program, University of California Berkeley, CA, United States
| | - Karsten Gronert
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, United States
- Vision Science Program, University of California Berkeley, CA, United States
- Infectious Disease and Immunity Program, University of California Berkeley, CA, United States
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Liu HH, Cullen PF, Sivak JM, Gronert K, Flanagan JG. Protective Effects of Lipoxin A 4 and B 4 Signaling on the Inner Retina in a Mouse Model of Experimental Glaucoma. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.17.575414. [PMID: 38293224 PMCID: PMC10827219 DOI: 10.1101/2024.01.17.575414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Glaucoma is a common neurodegenerative disease characterized by progressive degeneration of retinal ganglion cells (RGCs) and the retinal nerve fiber layer (RNFL), resulting in a gradual decline of vision. A recent study by our groups indicated that the levels of lipoxins A4 (LXA4) and B4 (LXB4) in the retina and optic nerve decrease following acute injury, and that restoring their function is neuroprotective. Lipoxins are members of the specialized pro-resolving mediator (SPM) family and play key roles to mitigate and resolve chronic inflammation and tissue damage. Yet, knowledge about lipoxin neuroprotective activity remains limited. Here we investigate the in vivo efficacy of exogenous LXA4 and LXB4 administration on the inner retina in a mouse model of chronic experimental glaucoma. To investigate the contribution of LXA4 signaling we used transgenic knockout (KO) mice lacking the two mouse LXA4 receptors (Fpr2/Fpr3-/-). Functional and structural changes of inner retinal neurons were assessed longitudinally using electroretinogram (ERG) and optical coherence tomography (OCT). At the end of the experiment, retinal samples were harvested for immunohistological assessment. While both lipoxins generated protective trends, only LXB4 treatment was significant, and consistently more efficacious than LXA4 in all endpoints. Both lipoxins also appeared to dramatically reduce Müller glial reactivity following injury. In comparison, Fpr2/Fpr3 deletion significantly worsened inner retinal injury and function, consistent with an essential protective role for endogenous LXA4. Together, these results support further exploration of lipoxin signaling as a treatment for glaucomatous neurodegeneration.
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Affiliation(s)
- Hsin-Hua Liu
- Herbert Wertheim School of Optometry and Vision Science, University of California at Berkeley, Berkeley, California, United States
| | - Paul F. Cullen
- Herbert Wertheim School of Optometry and Vision Science, University of California at Berkeley, Berkeley, California, United States
| | - Jeremy M. Sivak
- Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Karsten Gronert
- Herbert Wertheim School of Optometry and Vision Science, University of California at Berkeley, Berkeley, California, United States
| | - John G. Flanagan
- Herbert Wertheim School of Optometry and Vision Science, University of California at Berkeley, Berkeley, California, United States
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4
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Karnam S, Maurya S, Ng E, Choudhary A, Thobani A, Flanagan JG, Gronert K. Dysregulation of Neuroprotective Lipoxin Pathway in Astrocytes in Response to Cytokines and Ocular Hypertension. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.22.546157. [PMID: 37425861 PMCID: PMC10327029 DOI: 10.1101/2023.06.22.546157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Glaucoma leads to vision loss due to retinal ganglion cell death. Astrocyte reactivity contributes to neurodegeneration. Our recent study found that lipoxin B4 (LXB4), produced by retinal astrocytes, has direct neuroprotective actions on retinal ganglion cells. In this study, we aimed to investigate how the autacoid LXB4 influences astrocyte activity in the retina under inflammatory cytokine-induced activation and during ocular hypertension. The protective activity of LXB4 was investigated in vivo using the mouse silicone-oil model of chronic ocular hypertension (n=40). By employing a range of analytical techniques, including bulk RNA-seq, RNAscope in-situ hybridization, qPCR, and lipidomic analyses, we discovered the formation of lipoxins and expression of the lipoxin pathway in rodents (including the retina and optic nerve), primates (optic nerve), and human brain astrocytes, indicating the presence of this neuroprotective pathway across various species. Findings in the mouse retina identified significant dysregulation of the lipoxin pathway in response to chronic ocular hypertension, leading to an increase in 5-lipoxygenase (5-LOX) activity and a decrease in 15-LOX activity. This dysregulation was coincident with a marked upregulation of astrocyte reactivity. Reactive human brain astrocytes also showed a significant increase in 5-LOX. Treatment with LXB4 amplified the lipoxin biosynthetic pathway by restoring and amplifying the generation of another member of the lipoxin family, LXA4, and mitigated astrocyte reactivity in mouse retinas and human brain astrocytes. In conclusion, the lipoxin pathway is functionally expressed in rodents, primates, and human astrocytes, and is a resident neuroprotective pathway that is downregulated in reactive astrocytes. Novel cellular targets for LXB4's neuroprotective action are inhibition of astrocyte reactivity and restoration of lipoxin generation. Amplifying the lipoxin pathway is a potential target to disrupt or prevent astrocyte reactivity in neurodegenerative diseases, including retinal ganglion cell death in glaucoma.
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Affiliation(s)
- Shruthi Karnam
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, California, United States
| | - Shubham Maurya
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, California, United States
| | | | - Amodini Choudhary
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, California, United States
| | - Arzin Thobani
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, California, United States
| | - John G Flanagan
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, California, United States
| | - Karsten Gronert
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, California, United States
- Infectious Disease and Immunity Program, Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, CA, United States
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5
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Ramírez JM, Salobrar-García E, de Hoz R, Salazar JJ, Matamoros JA, Sánchez-Puebla L, López-Cuenca I, Fernández-Albarral JA, Ramírez AI. Laser-Induced Ocular Hypertension in a Mouse Model of Glaucoma. Methods Mol Biol 2023; 2708:49-56. [PMID: 37558959 DOI: 10.1007/978-1-0716-3409-7_6] [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] [Indexed: 08/11/2023]
Abstract
Glaucoma is a neurodegenerative disease that leads to the loss of retinal ganglion cells (RGC) and thus to blindness. There are numerous experimental models used for the study of this pathology. Among the different models, episcleral vein photocoagulation is one of the most widely used. In this model there is a transient increase in intraocular pressure that returns to normal values about 7 days after induction of ocular hypertension (OHT). In addition, typical glaucoma changes, such as loss of RGC, thinning of the optic nerve fiber layer, and glial activation, occur in this model. All these changes have been described in detail over time after OHT induction. In this chapter, we describe the detailed method of OHT induction in Swiss albino mice by diode laser photocoagulation of limbal and episcleral veins.
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Affiliation(s)
- José M Ramírez
- Ramón Castroviejo Institute for Ophthalmological Research, Complutense University of Madrid, Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, School of Medicine, Complutense University of Madrid, Madrid, Spain
- Institute for Health Research, Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Elena Salobrar-García
- Ramón Castroviejo Institute for Ophthalmological Research, Complutense University of Madrid, Madrid, Spain
- Institute for Health Research, Hospital Clínico San Carlos (IdISSC), Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - Rosa de Hoz
- Ramón Castroviejo Institute for Ophthalmological Research, Complutense University of Madrid, Madrid, Spain
- Institute for Health Research, Hospital Clínico San Carlos (IdISSC), Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - Juan J Salazar
- Ramón Castroviejo Institute for Ophthalmological Research, Complutense University of Madrid, Madrid, Spain
- Institute for Health Research, Hospital Clínico San Carlos (IdISSC), Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - José A Matamoros
- Ramón Castroviejo Institute for Ophthalmological Research, Complutense University of Madrid, Madrid, Spain
| | - Lidia Sánchez-Puebla
- Ramón Castroviejo Institute for Ophthalmological Research, Complutense University of Madrid, Madrid, Spain
| | - Inés López-Cuenca
- Ramón Castroviejo Institute for Ophthalmological Research, Complutense University of Madrid, Madrid, Spain
- Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - José A Fernández-Albarral
- Ramón Castroviejo Institute for Ophthalmological Research, Complutense University of Madrid, Madrid, Spain.
| | - Ana I Ramírez
- Ramón Castroviejo Institute for Ophthalmological Research, Complutense University of Madrid, Madrid, Spain.
- Institute for Health Research, Hospital Clínico San Carlos (IdISSC), Madrid, Spain.
- Department of Immunology, Ophthalmology and ENT, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain.
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6
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Mathew DJ, Livne-Bar I, Sivak JM. An inducible rodent glaucoma model that exhibits gradual sustained increase in intraocular pressure with distinct inner retina and optic nerve inflammation. Sci Rep 2021; 11:22880. [PMID: 34819548 PMCID: PMC8613281 DOI: 10.1038/s41598-021-02057-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/09/2021] [Indexed: 01/29/2023] Open
Abstract
Glaucoma is a chronic and progressive neurodegenerative disease of the optic nerve resulting in loss of retinal ganglion cells (RGCs) and vision. The most prominent glaucoma risk factor is increased intraocular pressure (IOP), and most models focus on reproducing this aspect to study disease mechanisms and targets. Yet, current models result in IOP profiles that often do not resemble clinical glaucoma. Here we introduce a new model that results in a gradual and sustained IOP increase over time. This approach modifies a circumlimbal suture method, taking care to make the sutures 'snug' instead of tight, without inducing an initial IOP spike. This approach did not immediately affect IOPs, but generated gradual ocular hypertension (gOHT) as the sutures tighten over time, in comparison to loosely sutured control eyes (CON), resulting in an average 12.6 mmHg increase in IOP at 17 weeks (p < 0.001). Corresponding characterization revealed relevant retinal and optic nerve pathology, such as thinning of the retinal nerve fiber layer, decreased optokinetic response, RGC loss, and optic nerve head remodeling. Yet, angles remained open, with no evidence of inflammation. Corresponding biochemical profiling indicated significant increases in TGF-β2 and 3, and IL-1 family cytokines in gOHT optic nerve tissues compared to CON, with accompanying microglial reactivity, consistent with active tissue injury and repair mechanisms. Remarkably, this signature was absent from optic nerves following acute ocular hypertension (aOHT) associated with intentionally tightened sutures, although the resulting RGC loss was similar in both methods. These results suggest that the pattern of IOP change has an important impact on underlying pathophysiology.
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Affiliation(s)
- David J Mathew
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
- Department of Lab Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Izhar Livne-Bar
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
- Department of Lab Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Jeremy M Sivak
- Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, ON, Canada.
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada.
- Department of Lab Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
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7
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Zhu J, Sainulabdeen A, Akers K, Adi V, Sims JR, Yarsky E, Yan Y, Yu Y, Ishikawa H, Leung CK, Wollstein G, Schuman JS, Wei W, Chan KC. Oral Scutellarin Treatment Ameliorates Retinal Thinning and Visual Deficits in Experimental Glaucoma. Front Med (Lausanne) 2021; 8:681169. [PMID: 34414202 PMCID: PMC8369066 DOI: 10.3389/fmed.2021.681169] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/07/2021] [Indexed: 01/29/2023] Open
Abstract
Purpose: Intraocular pressure (IOP) is currently the only modifiable risk factor for glaucoma, yet glaucoma can continue to progress despite controlled IOP. Thus, development of glaucoma neurotherapeutics remains an unmet need. Scutellarin is a flavonoid that can exert neuroprotective effects in the eye and brain. Here, we investigated the neurobehavioral effects of scutellarin treatment in a chronic IOP elevation model. Methods: Ten adult C57BL/6J mice were unilaterally injected with an optically clear hydrogel into the anterior chamber to obstruct aqueous outflow and induce chronic IOP elevation. Eight other mice received unilateral intracameral injection of phosphate-buffered saline only. Another eight mice with hydrogel-induced unilateral chronic IOP elevation also received daily oral gavage of 300 mg/kg scutellarin. Tonometry, optical coherence tomography, and optokinetics were performed longitudinally for 4 weeks to monitor the IOP, retinal nerve fiber layer thickness, total retinal thickness, visual acuity, and contrast sensitivity of both eyes in all three groups. Results: Intracameral hydrogel injection resulted in unilateral chronic IOP elevation with no significant inter-eye IOP difference between scutellarin treatment and untreated groups. Upon scutellarin treatment, the hydrogel-injected eyes showed less retinal thinning and reduced visual behavioral deficits when compared to the untreated, hydrogel-injected eyes. No significant difference in retinal thickness or optokinetic measures was found in the contralateral, non-treated eyes over time or between all groups. Conclusion: Using the non-invasive measuring platform, oral scutellarin treatment appeared to preserve retinal structure and visual function upon chronic IOP elevation in mice. Scutellarin may be a novel neurotherapeutic agent for glaucoma treatment.
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Affiliation(s)
- Jingyuan Zhu
- Beijing Tongren Eye Center, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Beijing Ophthalmology & Visual Sciences Key Lab, Medical Artificial Intelligence Research and Verification Key Laboratory of the Ministry of Industry and Information Technology, Beijing Tongren Hospital, Capital Medical University, Beijing, China,Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Anoop Sainulabdeen
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States,Department of Surgery and Radiology, College of Veterinary and Animal Sciences, Kerala Veterinary and Animal Sciences University, Thrissur, India
| | - Krystal Akers
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Vishnu Adi
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Jeffrey R. Sims
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Eva Yarsky
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Yi Yan
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Yu Yu
- Pleryon Therapeutics Limited, Shenzhen, China
| | - Hiroshi Ishikawa
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States,Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY, United States
| | - Christopher K. Leung
- Hong Kong Eye Hospital, University Eye Center, Hong Kong, China,Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China,Department of Ophthalmology, The University of Hong Kong, Hong Kong, China
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States,Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY, United States
| | - Joel S. Schuman
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States,Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY, United States,Center for Neural Science, College of Arts and Science, New York University, New York, NY, United States,Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States
| | - Wenbin Wei
- Beijing Tongren Eye Center, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Beijing Ophthalmology & Visual Sciences Key Lab, Medical Artificial Intelligence Research and Verification Key Laboratory of the Ministry of Industry and Information Technology, Beijing Tongren Hospital, Capital Medical University, Beijing, China,Wenbin Wei
| | - Kevin C. Chan
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States,Department of Biomedical Engineering, Tandon School of Engineering, New York University, New York, NY, United States,Center for Neural Science, College of Arts and Science, New York University, New York, NY, United States,Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States,Department of Radiology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, United States,*Correspondence: Kevin C. Chan
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8
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Wang X, Lou N, Eberhardt A, Yang Y, Kusk P, Xu Q, Förstera B, Peng S, Shi M, Ladrón-de-Guevara A, Delle C, Sigurdsson B, Xavier ALR, Ertürk A, Libby RT, Chen L, Thrane AS, Nedergaard M. An ocular glymphatic clearance system removes β-amyloid from the rodent eye. Sci Transl Med 2021; 12:12/536/eaaw3210. [PMID: 32213628 DOI: 10.1126/scitranslmed.aaw3210] [Citation(s) in RCA: 118] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 08/24/2019] [Accepted: 12/30/2019] [Indexed: 12/31/2022]
Abstract
Despite high metabolic activity, the retina and optic nerve head lack traditional lymphatic drainage. We here identified an ocular glymphatic clearance route for fluid and wastes via the proximal optic nerve in rodents. β-amyloid (Aβ) was cleared from the retina and vitreous via a pathway dependent on glial water channel aquaporin-4 (AQP4) and driven by the ocular-cranial pressure difference. After traversing the lamina barrier, intra-axonal Aβ was cleared via the perivenous space and subsequently drained to lymphatic vessels. Light-induced pupil constriction enhanced efflux, whereas atropine or raising intracranial pressure blocked efflux. In two distinct murine models of glaucoma, Aβ leaked from the eye via defects in the lamina barrier instead of directional axonal efflux. The results suggest that, in rodents, the removal of fluid and metabolites from the intraocular space occurs through a glymphatic pathway that might be impaired in glaucoma.
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Affiliation(s)
- Xiaowei Wang
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark.,Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
| | - Nanhong Lou
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
| | - Allison Eberhardt
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
| | - Yujia Yang
- Center for Eye Disease and Development, Vision Science Graduate Program, and School of Optometry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Peter Kusk
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Qiwu Xu
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
| | - Benjamin Förstera
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilians University of Munich (LMU), 81377 Munich, Germany.,Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center München, 85764 Munich, Germany
| | - Sisi Peng
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
| | - Meng Shi
- Center for Eye Disease and Development, Vision Science Graduate Program, and School of Optometry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Antonio Ladrón-de-Guevara
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
| | - Christine Delle
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Björn Sigurdsson
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Anna L R Xavier
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Ali Ertürk
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilians University of Munich (LMU), 81377 Munich, Germany.,Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center München, 85764 Munich, Germany
| | - Richard T Libby
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Lu Chen
- Center for Eye Disease and Development, Vision Science Graduate Program, and School of Optometry, University of California Berkeley, Berkeley, CA 94720, USA.
| | - Alexander S Thrane
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark.,Department of Ophthalmology, Haukeland University Hospital, Jonas Lies Vei 65, 5021 Bergen, Norway
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark. .,Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, Rochester, NY 14642, USA
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9
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Lakshmanan Y, Wong FSY, Zuo B, Bui BV, Chan HHL. Longitudinal outcomes of circumlimbal suture model-induced chronic ocular hypertension in Sprague-Dawley albino rats. Graefes Arch Clin Exp Ophthalmol 2020; 258:2715-2728. [PMID: 32623578 DOI: 10.1007/s00417-020-04820-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 06/03/2020] [Accepted: 06/26/2020] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To characterise longitudinal structural and functional changes in albino Sprague-Dawley rats following circumlimbal suture ocular hypertension (OHT) induction. METHODS Ten-week-old rats (n = 24) underwent suture implantation around the limbal region in both eyes. On the next day, the suture was removed from one eye (control eyes) and left intact in the other eye (OHT eyes) of each animal. Intraocular pressure (IOP) was monitored weekly twice for the next 15 weeks. Optical coherence tomography (OCT) and electroretinogram (ERG) were measured at baseline and weeks 4, 8, 12, and 15, and eyes were then collected for histological assessment. RESULTS Sutured eyes (n = 12) developed IOP elevation of ~ 50% in the first 2 weeks that was sustained at ~ 25% above the control eye up to week 15 (p = 0.001). Animals with insufficient IOP elevation (n = 6), corneal changes (n = 3), and attrition (n = 3) were excluded from the analysis. OHT eyes developed significant retinal nerve fibre layer (RNFL) thinning (week 4: - 19 ± 14%, p = 0.10; week 8: - 17 ± 12%, p = 0.04; week 12: - 16 ± 10%, p = 0.04, relative to baseline) and reduction in retinal ganglion cell (RGC) density (- 32 ± 26%, p = 0.02). At week 15, both inner (9 ± 7%, p = 0.01) and outer retinal layer thicknesses (6.0 ± 5%, p = 0.001) showed a mild increase in thicknesses. The positive scotopic threshold response (- 28 ± 25%, p = 0.04) and a-wave were significantly reduced at week 12 (- 35 ± 21%; p = 0.04), whereas b-wave was not significantly affected (week 12: - 18 ± 27%, p = 0.24). CONCLUSION The circumlimbal suture model produced a chronic, moderate IOP elevation in an albino strain that led to RNFL thinning and reduced RGC density along with the reductions in ganglion and photoreceptoral cell functions. There was a small thickening in both outer and inner retinal layers.
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Affiliation(s)
- Yamunadevi Lakshmanan
- Laboratory of Experimental Optometry (Neuroscience), School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Francisca Siu Yin Wong
- Laboratory of Experimental Optometry (Neuroscience), School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Bing Zuo
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Bang Viet Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, Australia
| | - Henry Ho-Lung Chan
- Laboratory of Experimental Optometry (Neuroscience), School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China. .,Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China.
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10
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Bhandari A, Smith JC, Zhang Y, Jensen AA, Reid L, Goeser T, Fan S, Ghate D, Van Hook MJ. Early-Stage Ocular Hypertension Alters Retinal Ganglion Cell Synaptic Transmission in the Visual Thalamus. Front Cell Neurosci 2019; 13:426. [PMID: 31607867 PMCID: PMC6761307 DOI: 10.3389/fncel.2019.00426] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/04/2019] [Indexed: 12/21/2022] Open
Abstract
Axonopathy is a hallmark of many neurodegenerative diseases including glaucoma, where elevated intraocular pressure (ocular hypertension, OHT) stresses retinal ganglion cell (RGC) axons as they exit the eye and form the optic nerve. OHT causes early changes in the optic nerve such as axon atrophy, transport inhibition, and gliosis. Importantly, many of these changes appear to occur prior to irreversible neuronal loss, making them promising points for early diagnosis of glaucoma. It is unknown whether OHT has similarly early effects on the function of RGC output to the brain. To test this possibility, we elevated eye pressure in mice by anterior chamber injection of polystyrene microbeads. Five weeks post-injection, bead-injected eyes showed a modest RGC loss in the peripheral retina, as evidenced by RBPMS antibody staining. Additionally, we observed reduced dendritic complexity and lower spontaneous spike rate of On-αRGCs, targeted for patch clamp recording and dye filling using a Opn4-Cre reporter mouse line. To determine the influence of OHT on retinal projections to the brain, we expressed Channelrhodopsin-2 (ChR2) in melanopsin-expressing RGCs by crossing the Opn4-Cre mouse line with a ChR2-reporter mouse line and recorded post-synaptic responses in thalamocortical relay neurons in the dorsal lateral geniculate nucleus (dLGN) of the thalamus evoked by stimulation with 460 nm light. The use of a Opn4-Cre reporter system allowed for expression of ChR2 in a narrow subset of RGCs responsible for image-forming vision in mice. Five weeks following OHT induction, paired pulse and high-frequency stimulus train experiments revealed that presynaptic vesicle release probability at retinogeniculate synapses was elevated. Additionally, miniature synaptic current frequency was slightly reduced in brain slices from OHT mice and proximal dendrites of post-synaptic dLGN relay neurons, assessed using a Sholl analysis, showed a reduced complexity. Strikingly, these changes occurred prior to major loss of RGCs labeled with the Opn4-Cre mouse, as indicated by immunofluorescence staining of ChR2-expressing retinal neurons. Thus, OHT leads to pre- and post-synaptic functional and structural changes at retinogeniculate synapses. Along with RGC dendritic remodeling and optic nerve transport changes, these retinogeniculate synaptic changes are among the earliest signs of glaucoma.
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Affiliation(s)
- Ashish Bhandari
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Jennie C Smith
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Yang Zhang
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States.,Creighton University School of Medicine, Omaha, NE, United States.,Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Aaron A Jensen
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Lisa Reid
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Toni Goeser
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Shan Fan
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Deepta Ghate
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Matthew J Van Hook
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
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11
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Biswas S, Wan KH. Review of rodent hypertensive glaucoma models. Acta Ophthalmol 2019; 97:e331-e340. [PMID: 30549197 DOI: 10.1111/aos.13983] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 11/04/2018] [Indexed: 12/11/2022]
Abstract
Glaucoma is a neurodegenerative disease characterized by the progressive loss of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is a primary risk factor for the development and progression of glaucoma. Rodent models of glaucoma have greatly improved our understanding of the pathophysiology of glaucoma and served as a useful tool to investigate neuroprotective agents. An ideal glaucoma animal model should be easy to induce, reproducible, biologically plausible and predictable. Of the available animal models of glaucoma, rodents are commonly studied because they have a relatively short life span and can be genetically altered. A successful hypertensive glaucoma model should induce structural glaucomatous changes: including loss of retinal nerve fibres, retinal ganglion cells and optic-disc cupping along with IOP elevation. The level and duration of IOP elevation should be titratable depending on the targeted glaucomatous damage. This review summarizes the outcomes of induced rodent hypertensive glaucoma models including intracameral injection of microbeads, laser photocoagulation, episcleral vein cauterization, injection of hypertonic saline and hyaluronic acid. We aim to provide a detailed overview of each of the models with a focus on parameters that defines a successful glaucoma model. The induced IOP elevation and duration of elevation varied among the different models and strain of rodent; nonetheless, they all achieved a sustainable raised IOP with corresponding RGC loss. The limitations of each model are discussed.
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Affiliation(s)
- Sayantan Biswas
- Department of Optometry NSHM Knowledge Campus Maulana Abul Kalam Azad University of Technology Kolkata India
| | - Kelvin H. Wan
- Department of Ophthalmology & Visual Sciences Chinese University of Hong Kong Hong Kong Hong Kong
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12
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He Z, Zhao D, van Koeverden AK, Nguyen CT, Lim JKH, Wong VHY, Vingrys AJ, Bui BV. A Model of Glaucoma Induced by Circumlimbal Suture in Rats and Mice. J Vis Exp 2018. [PMID: 30346390 DOI: 10.3791/58287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The circumlimbal suture is a technique for inducing experimental glaucoma in rodents by chronically elevating intraocular pressure (IOP), a well-known risk factor for glaucoma. This protocol demonstrates a step-by-step guide on this technique in Long Evans rats and C57BL/6 mice. Under general anesthesia, a "purse-string" suture is applied on the conjunctiva, around the equator and behind the limbus of the eye. The fellow eye serves as an untreated control. Over the duration of our study, which was a period of 8 weeks for rats and 12 weeks for mice, IOP remained elevated, as measured regularly by rebound tonometry in conscious animals without topical anesthesia. In both species, the sutured eyes showed electroretinogram features consistent with preferential inner retinal dysfunction. Optical coherence tomography showed selective thinning of the retinal nerve fiber layer. Histology of the rat retina in cross-section found reduced cell density in the ganglion cell layer, but no change in other cellular layers. Staining of flat-mounted mouse retinae with a ganglion cell specific marker (RBPMS) confirmed ganglion cell loss. The circumlimbal suture is a simple, minimally invasive and cost-effective way to induce ocular hypertension that leads to ganglion cell injury in both rats and mice.
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Affiliation(s)
- Zheng He
- Department of Optometry and Vision Sciences, University of Melbourne
| | - Da Zhao
- Department of Optometry and Vision Sciences, University of Melbourne
| | | | | | - Jeremiah K H Lim
- Department of Optometry and Vision Sciences, University of Melbourne
| | - Vickie H Y Wong
- Department of Optometry and Vision Sciences, University of Melbourne
| | - Algis J Vingrys
- Department of Optometry and Vision Sciences, University of Melbourne
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne;
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13
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Corneal Vibrations during Intraocular Pressure Measurement with an Air-Puff Method. JOURNAL OF HEALTHCARE ENGINEERING 2018; 2018:5705749. [PMID: 29610655 PMCID: PMC5828335 DOI: 10.1155/2018/5705749] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 10/25/2017] [Accepted: 12/11/2017] [Indexed: 12/19/2022]
Abstract
Introduction The paper presents a commentary on the method of analysis of corneal vibrations occurring during eye pressure measurements with air-puff tonometers, for example, Corvis. The presented definition and measurement method allow for the analysis of image sequences of eye responses—cornea deformation. In particular, the outer corneal contour and sclera fragments are analysed, and 3D reconstruction is performed. Methods On this basis, well-known parameters such as eyeball reaction or corneal response are determined. The next steps of analysis allow for automatic and reproducible separation of four different corneal vibrations. These vibrations are associated with (1) the location of the maximum of cornea deformation; (2) the cutoff area measured in relation to the cornea in a steady state; (3) the maximum of peaks occurring between applanations; and (4) the other characteristic points of the corneal contour. Results The results obtained enable (1) automatic determination of the amplitude of vibrations; (2) determination of the frequency of vibrations; and (3) determination of the correlation between the selected types of vibrations. Conclusions These are diagnostic features that can be directly applied clinically for new and archived data.
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