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Nayak A, Deveswaran R, Swati S, Srividhya L. Agreement of tonometer for measuring intraocular pressure in Wistar rats: a systematic review. Eur J Med Res 2024; 29:332. [PMID: 38880889 PMCID: PMC11181524 DOI: 10.1186/s40001-024-01927-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 06/06/2024] [Indexed: 06/18/2024] Open
Abstract
Glaucoma is the most common cause of irreversible blindness in the world. It is associated with elevated intraocular pressure (IOP). Fluctuations in tonometer readings have implications for glaucoma research, where accurate IOP measurements are vital for evaluating disease progression and treatment efficacy. Researchers should carefully select the appropriate tonometer and consider biases associated with different tonometers. Validation against standard measurements can improve IOP measurement accuracy in rat models. In conclusion, this systematic review will emphasize on the importance of selecting the appropriate tonometer for IOP measurement in rat models, considering potential biases and their implications for glaucoma research. Accurate and consistent IOP measurement in rat models is crucial for understanding glaucoma pathophysiology and developing effective treatments. This systematic review aims to assess agreement among tonometers used for measuring IOP in Wistar rat models primarily focusing on TonoLab, TonoVet, and Tono-pen. The review was conducted using PRISMA guidelines. Two articles were included for qualitative synthesis. The studies compared manometric IOP with TonoLab, rebound tonometer, and Tono-pen XL readings. It was observed that TonoLab consistently underestimated IOP, while Tono-pen XL tended to overestimate IOP compared to manometric measurements. The study's findings will help researchers in making decisions about tonometer selection, leading to more reliable outcomes in glaucoma research using rat models. Further research, specifically RCT's (randomized controlled trial) is needed to confirm the results and enhance IOP measurement precision in rat models.
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Affiliation(s)
- Anush Nayak
- Optometry Division, Department of Allied Health Sciences, Faculty of Life and Allied Health Sciences, M S Ramaiah University of Applied Sciences, Bengaluru, India.
| | - R Deveswaran
- Department of Pharmaceuticals, Faculty of Pharmacy, M S Ramaiah University of Applied Sciences, Bengaluru, India
| | - S Swati
- Department of Biotechnology, Faculty of Life and Allied Health Sciences, M S Ramaiah University of Applied Sciences, Bengaluru, India
| | - L Srividhya
- Optometry Division, Department of Allied Health Sciences, Faculty of Life and Allied Health Sciences, M S Ramaiah University of Applied Sciences, Bengaluru, India
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Becker S, L'Ecuyer Z, Jones BW, Zouache MA, McDonnell FS, Vinberg F. Modeling complex age-related eye disease. Prog Retin Eye Res 2024; 100:101247. [PMID: 38365085 PMCID: PMC11268458 DOI: 10.1016/j.preteyeres.2024.101247] [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: 08/15/2023] [Revised: 01/31/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024]
Abstract
Modeling complex eye diseases like age-related macular degeneration (AMD) and glaucoma poses significant challenges, since these conditions depend highly on age-related changes that occur over several decades, with many contributing factors remaining unknown. Although both diseases exhibit a relatively high heritability of >50%, a large proportion of individuals carrying AMD- or glaucoma-associated genetic risk variants will never develop these diseases. Furthermore, several environmental and lifestyle factors contribute to and modulate the pathogenesis and progression of AMD and glaucoma. Several strategies replicate the impact of genetic risk variants, pathobiological pathways and environmental and lifestyle factors in AMD and glaucoma in mice and other species. In this review we will primarily discuss the most commonly available mouse models, which have and will likely continue to improve our understanding of the pathobiology of age-related eye diseases. Uncertainties persist whether small animal models can truly recapitulate disease progression and vision loss in patients, raising doubts regarding their usefulness when testing novel gene or drug therapies. We will elaborate on concerns that relate to shorter lifespan, body size and allometries, lack of macula and a true lamina cribrosa, as well as absence and sequence disparities of certain genes and differences in their chromosomal location in mice. Since biological, rather than chronological, age likely predisposes an organism for both glaucoma and AMD, more rapidly aging organisms like small rodents may open up possibilities that will make research of these diseases more timely and financially feasible. On the other hand, due to the above-mentioned anatomical and physiological features, as well as pharmacokinetic and -dynamic differences small animal models are not ideal to study the natural progression of vision loss or the efficacy and safety of novel therapies. In this context, we will also discuss the advantages and pitfalls of alternative models that include larger species, such as non-human primates and rabbits, patient-derived retinal organoids, and human organ donor eyes.
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Affiliation(s)
- Silke Becker
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Zia L'Ecuyer
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Bryan W Jones
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Moussa A Zouache
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Fiona S McDonnell
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Frans Vinberg
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Biomedical Engineering, University of Utah, Salt Lake City, UT, USA.
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Eraslan M, Çerman E, Bozkurt S, Genç D, Virlan AT, Demir CS, Akkoç T, Karaöz E, Akkoç T. Mesenchymal stem cells differentiate to retinal ganglion-like cells in rat glaucoma model induced by polystyrene microspheres. Tissue Cell 2023; 84:102199. [PMID: 37633122 DOI: 10.1016/j.tice.2023.102199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 08/17/2023] [Accepted: 08/17/2023] [Indexed: 08/28/2023]
Abstract
AIM The study aimed to evaluate the differentiation ability of intravitreally injected rat bone marrow-derived mesenchymal stem cells (rBM-MSCs) to retinal ganglion-like cells in a polystyrene microsphere induced rat glaucoma model. MATERIALS AND METHODS The glaucoma rat model was generated via intracameral injection of 7 microliter polystyrene microspheres. Green fluorescence protein-labeled (GFP) rBM-MSCs were transplanted intravitreally at or after induction of ocular hypertension (OHT), depending on the groups. By the end of the fourth week, flat-mount retinal dissection was performed, and labeled against Brn3a, CD90, GFAP, CD11b, Vimentin, and localization of GFP positive rBM-MSCs was used for evaluation through immunofluorescence staining and to count differentiated retinal cells by flow cytometry. From 34 male Wistar albino rats, 56 eyes were investigated. RESULTS Flow cytometry revealed significantly increased CD90 and Brn3a positive cells in glaucoma induced and with rBM-MSC injected groups compared to control(P = 0.006 and P = 0.003 respectively), sham-operated (P = 0.007 and P < 0.001 respectively), and only rBM-MSCs injected groups (P = 0.002 and P = 0.009 respectively). Immunofluorescence microscopy revealed differentiation of GFP labeled stem cells to various retinal cells, including ganglion-like cells. rBM-MSCs were observable in ganglion cells, inner and outer nuclear retinal layers in rBM-MSCs injected eyes. CONCLUSION Intravitreally transplanted rBM-MSCs differentiated into retinal cells, including ganglion-like cells, which successfully created a glaucoma model damaged with polystyrene microspheres. Promisingly, MSCs may have a role in neuro-protection and neuro-regeneration treatment of glaucoma in the future.
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Affiliation(s)
- Muhsin Eraslan
- Department of Ophthalmology, Marmara University Faculty of Medicine, Istanbul, Turkey.
| | - Eren Çerman
- Department of Ophthalmology, Marmara University Faculty of Medicine, Istanbul, Turkey
| | - Süheyla Bozkurt
- Department of Pathology, Marmara University Faculty of Medicine, Istanbul, Turkey
| | - Deniz Genç
- Department of Pediatric Diseases, Faculty of Health Sciences, Muğla Sıtkı Koçman University, Muğla, Turkey
| | - Aysın Tulunay Virlan
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, Scotland, UK
| | - Cansu Subaşı Demir
- Center for Regenerative Medicine and Stem Cell Research & Manufacturing (LivMedCell), Istanbul, Turkey
| | - Tolga Akkoç
- Genetic Engineering and Biotechnology Institute, Tubitak Marmara Research Center, Kocaeli, Turkey
| | - Erdal Karaöz
- Department of Histology & Embryology, Istinye University Faculty of Medicine, Istanbul, Turkey; Center for Stem Cell and Tissue Engineering Research & Practice, Istinye University, Istanbul, Turkey
| | - Tunç Akkoç
- Department of Pediatric Allergy and Immunology, Marmara University Faculty of Medicine, Istanbul, Turkey; Department of Immunology, Marmara University Faculty of Medicine, Istanbul, Turkey; Marstem Cell Technologies, Marmara University Technopark, İstanbul, Turkey
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Erb C, Reinehr S, Theiss C, Dick HB, Joachim SC. HSP27 induced glaucomatous damage in mice of young and advanced age. Front Cell Neurosci 2023; 17:1257297. [PMID: 37744880 PMCID: PMC10513106 DOI: 10.3389/fncel.2023.1257297] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/25/2023] [Indexed: 09/26/2023] Open
Abstract
Introduction Age-related diseases such as glaucoma, a leading cause of blindness, are having an upward trend due to an aging society. In glaucoma, some patients display altered antibody profiles and increased antibody titers, for example against heat shock protein 27 (HSP27). An intravitreal injection of HSP27 leads to glaucoma-like damage in rats. We now aimed to investigate if aged mice are more prone to this damage than younger ones. Methods We intravitreally injected HSP27 into young (1-2 months) and aged (7-8 months) mice to compare glaucomatous damage. Respective age-matched controls received PBS. Not injected eyes served as naive controls. Results Optical coherence tomography 4 weeks after injection showed no changes in retinal thickness in all groups at both ages. Cell counts and RT-qPCR revealed a significant reduction in RGC numbers in HSP27 mice at both ages. Comparing aged and young HSP27 mice, no differences in Rbpms and Pou4f1 (RGCs) expression was detected, while the Tubb3 expression (neuronal cells) was significantly upregulated in aged HSP27 animals. Neither microglia/macrophages nor (resident) microglia counts revealed significant differences in HSP27 mice at both ages. Nevertheless, increased relative Iba1 and Tmem119 expression was detected in young and aged HSP27 mice. Aged HSP27 mice displayed a significantly lower Iba1 expression than young ones, whereas Cd68 levels were upregulated. A larger GFAP+ area and an upregulation of GFAP expression in HSP27 animals of both ages indicated a macrogliosis. Also, elevated Il1b and Nos2 expression levels were observed in young and aged HSP27 mice. However, only Il1b levels were upregulated when comparing 7-8 months to 1-2 months old animals. A larger HSP25+ area was seen in aged HSP27 animals, while Hspb2 expression levels were downregulated in both HSP27 groups. The aged HSP27 group displayed an upregulated Hspb2 expression compared to young mice. Furthermore, a higher optic nerve degeneration score was noted in young and aged HSP27 groups. Discussion These findings indicate that an intravitreal injection of HSP27 led to RGC loss accompanied by inflammation. Age-dependent effects (7-8 months vs. 1-2 months) were not very prominent. The results suggest a potential role of extracellular HSP27 in the development of glaucoma.
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Affiliation(s)
- Clivia Erb
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Sabrina Reinehr
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Carsten Theiss
- Institute of Anatomy, Department of Cytology, Ruhr-University Bochum, Bochum, Germany
| | - H. Burkhard Dick
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Stephanie C. Joachim
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
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Sikiric P, Kokot A, Kralj T, Zlatar M, Masnec S, Lazic R, Loncaric K, Oroz K, Sablic M, Boljesic M, Antunovic M, Sikiric S, Strbe S, Stambolija V, Beketic Oreskovic L, Kavelj I, Novosel L, Zubcic S, Krezic I, Skrtic A, Jurjevic I, Boban Blagaic A, Seiwerth S, Staresinic M. Stable Gastric Pentadecapeptide BPC 157-Possible Novel Therapy of Glaucoma and Other Ocular Conditions. Pharmaceuticals (Basel) 2023; 16:1052. [PMID: 37513963 PMCID: PMC10385428 DOI: 10.3390/ph16071052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/01/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
Recently, stable gastric pentadecapeptide BPC 157 therapy by activation of collateral pathways counteracted various occlusion/occlusion-like syndromes, vascular, and multiorgan failure, and blood pressure disturbances in rats with permanent major vessel occlusion and similar procedures disabling endothelium function. Thereby, we revealed BPC 157 cytoprotective therapy with strong vascular rescuing capabilities in glaucoma therapy. With these capabilities, BPC 157 therapy can recover glaucomatous rats, normalize intraocular pressure, maintain retinal integrity, recover pupil function, recover retinal ischemia, and corneal injuries (i.e., maintained transparency after complete corneal abrasion, corneal ulceration, and counteracted dry eye after lacrimal gland removal or corneal insensitivity). The most important point is that in glaucomatous rats (three of four episcleral veins cauterized) with high intraocular pressure, all BPC 157 regimens immediately normalized intraocular pressure. BPC 157-treated rats exhibited normal pupil diameter, microscopically well-preserved ganglion cells and optic nerve presentation, normal fundus presentation, nor- mal retinal and choroidal blood vessel presentation, and normal optic nerve presentation. The one episcleral vein rapidly upgraded to accomplish all functions in glaucomatous rats may correspond with occlusion/occlusion-like syndromes of the activated rescuing collateral pathway (azygos vein direct blood flow delivery). Normalized intraocular pressure in glaucomatous rats corresponded to the counteracted intra-cranial (superior sagittal sinus), portal, and caval hypertension, and aortal hypotension in occlusion/occlusion-like syndromes, were all attenuated/eliminated by BPC 157 therapy. Furthermore, given in other eye disturbances (i.e., retinal ischemia), BPC 157 instantly breaks a noxious chain of events, both at an early stage and an already advanced stage. Thus, we further advocate BPC 157 as a therapeutic agent in ocular disease.
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Affiliation(s)
- Predrag Sikiric
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Antonio Kokot
- Department of Anatomy and Neuroscience, Faculty of Medicine, J.J. Strossmayer University of Osijek, 31000 Osijek, Croatia
| | - Tamara Kralj
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Mirna Zlatar
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Sanja Masnec
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Ratimir Lazic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Kristina Loncaric
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Katarina Oroz
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Marko Sablic
- Department of Anatomy and Neuroscience, Faculty of Medicine, J.J. Strossmayer University of Osijek, 31000 Osijek, Croatia
| | - Marta Boljesic
- Department of Anatomy and Neuroscience, Faculty of Medicine, J.J. Strossmayer University of Osijek, 31000 Osijek, Croatia
| | - Marko Antunovic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Suncana Sikiric
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Sanja Strbe
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Vasilije Stambolija
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | | | - Ivana Kavelj
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Luka Novosel
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Slavica Zubcic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Ivan Krezic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Anita Skrtic
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Ivana Jurjevic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Alenka Boban Blagaic
- Department of Pharmacology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Sven Seiwerth
- Department of Pathology, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
| | - Mario Staresinic
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia
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Wang HN, Qian WJ, Zhao GL, Li F, Miao YY, Lei B, Sun XH, Wang ZF. L- and T-type Ca 2+ channels dichotomously contribute to retinal ganglion cell injury in experimental glaucoma. Neural Regen Res 2023; 18:1570-1577. [PMID: 36571364 PMCID: PMC10075096 DOI: 10.4103/1673-5374.360277] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Retinal ganglion cell apoptotic death is the main pathological characteristic of glaucoma, which is the leading cause of irreversible blindness. Disruption of Ca2+ homeostasis plays an important role in glaucoma. Voltage-gated Ca2+ channel blockers have been shown to improve vision in patients with glaucoma. However, whether and how voltage-gated Ca2+ channels are involved in retinal ganglion cell apoptotic death are largely unknown. In this study, we found that total Ca2+ current densities in retinal ganglion cells were reduced in a rat model of chronic ocular hypertension experimental glaucoma, as determined by whole-cell patch-clamp electrophysiological recordings. Further analysis showed that L-type Ca2+ currents were downregulated while T-type Ca2+ currents were upregulated at the later stage of glaucoma. Western blot assay and immunofluorescence experiments confirmed that expression of the CaV1.2 subunit of L-type Ca2+ channels was reduced and expression of the CaV3.3 subunit of T-type Ca2+ channels was increased in retinas of the chronic ocular hypertension model. Soluble tumor necrosis factor-α, an important inflammatory factor, inhibited the L-type Ca2+ current of isolated retinal ganglion cells from control rats and enhanced the T-type Ca2+ current. These changes were blocked by the tumor necrosis factor-α inhibitor XPro1595, indicating that both types of Ca2+ currents may be mediated by soluble tumor necrosis factor-α. The intracellular mitogen-activated protein kinase/extracellular signal-regulated kinase pathway and nuclear factor kappa-B signaling pathway mediate the effects of tumor necrosis factor-α. TUNEL assays revealed that mibefradil, a T-type calcium channel blocker, reduced the number of apoptotic retinal ganglion cells in the rat model of chronic ocular hypertension. These results suggest that T-type Ca2+ channels are involved in disrupted Ca2+ homeostasis and apoptosis of retinal ganglion cells in glaucoma, and application of T-type Ca2+ channel blockers, especially a specific CaV3.3 blocker, may be a potential strategy for the treatment of glaucoma.
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Affiliation(s)
- Hong-Ning Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Wen-Jing Qian
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Guo-Li Zhao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Fang Li
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yan-Ying Miao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Bo Lei
- Institutes of Neuroscience and Third Affiliated Hospital, Henan Provincial People's Hospital, Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan Province, China
| | - Xing-Huai Sun
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, NHC Key Laboratory of Myopia, Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Zhong-Feng Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
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Peng MG, Lee J, Ho W, Kim T, Yao P, Medvidovic S, Alas B, Wu V, Runner MM, Gokoffski KK. AxonQuantifier: A semi-automated program for quantifying axonal density from whole-mounted optic nerves. J Neurosci Methods 2023; 394:109895. [PMID: 37315846 PMCID: PMC10330882 DOI: 10.1016/j.jneumeth.2023.109895] [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: 03/08/2023] [Revised: 05/17/2023] [Accepted: 05/19/2023] [Indexed: 06/16/2023]
Abstract
BACKGROUND Here, we present a semi-automated method for quantifying retinal ganglion cell (RGC) axon density at different distances from the optic nerve crush site using longitudinal, confocal microscopy images taken from whole-mounted optic nerves. This method employs the algorithm AxonQuantifier which operates on the freely available program, ImageJ. NEW METHOD To validate this method, seven adult male Long Evans rats underwent optic nerve crush injury followed by in vivo treatment with electric fields of varying strengths for 30 days to produce optic nerves with a wide range of axon densities distal to the optic nerve crush site. Prior to euthanasia, RGC axons were labelled with intravitreal injections of cholera toxin B conjugated to Alexa Fluor 647. After dissection, optic nerves underwent tissue clearing, were whole-mounted, and imaged longitudinally using confocal microscopy. COMPARISON WITH EXISTING METHODS Five masked raters quantified RGC axon density at 250, 500, 750, 1000, 1250, 1500, 1750, and 2000 µm distances past the optic nerve crush site for the seven optic nerves manually and using AxonQuantifier. Agreement between these methods was assessed using Bland-Altman plots and linear regression. Inter-rater agreement was assessed using the intra-class coefficient. RESULTS Semi-automated quantification of RGC axon density demonstrated improved inter-rater agreement and reduced bias values as compared to manual quantification, while also increasing time efficiency 4-fold. Relative to manual quantification, AxonQuantifier tended to underestimate axon density. CONCLUSIONS AxonQuantifier is a reliable and efficient method for quantifying axon density from whole mount optic nerves.
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Affiliation(s)
- Micalla G Peng
- Department of Ophthalmology, Keck School of Medicine, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Jonathan Lee
- Department of Ophthalmology, Keck School of Medicine, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Wilson Ho
- Department of Ophthalmology, Keck School of Medicine, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Timothy Kim
- Department of Ophthalmology, Keck School of Medicine, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Petcy Yao
- Department of Ophthalmology, Keck School of Medicine, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Sasha Medvidovic
- Department of Ophthalmology, Keck School of Medicine, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Basheer Alas
- Department of Ophthalmology, Keck School of Medicine, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Vivian Wu
- Department of Ophthalmology, Keck School of Medicine, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Margaret M Runner
- Department of Ophthalmology, Keck School of Medicine, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA; Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, USA; Associated Retinal Consultants, PC, Department of Ophthalmology, Oakland University William Beaumont School of Medicine, Royal Oak, MI, USA
| | - Kimberly K Gokoffski
- Department of Ophthalmology, Keck School of Medicine, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA.
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Agarwal R, Agarwal P, Iezhitsa I. Exploring the current use of animal models in glaucoma drug discovery: where are we in 2023? Expert Opin Drug Discov 2023; 18:1287-1300. [PMID: 37608634 DOI: 10.1080/17460441.2023.2246892] [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: 05/25/2023] [Accepted: 08/08/2023] [Indexed: 08/24/2023]
Abstract
INTRODUCTION Animal models are widely used in glaucoma-related research. Since the elevated intraocular pressure (IOP) is a major risk factor underlying the disease pathogenesis, animal models with high IOP are commonly used. However, models are also used to represent the clinical context of glaucomatous changes developing despite a normal IOP. AREAS COVERED Herein, the authors discuss the various factors that contribute to the quality of studies using animal models based on the evaluation of studies published in 2022. The factors affecting the quality of studies using animal models, such as the animal species, age, and sex, are discussed, along with various methods and outcomes of studies involving different animal models of glaucoma. EXPERT OPINION Translating animal research data to clinical applications remains challenging. Our observations in this review clearly indicate that many studies lack scientific robustness not only in their experiment conduct but also in data analysis, interpretation, and presentation. In this context, ensuring the internal validity of animal studies is the first step in quality assurance. External validity, however, is more challenging, and steps should be taken to satisfy external validity at least to some extent.
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Affiliation(s)
- Renu Agarwal
- School of Medicine, International Medical University, Bukit Jalil, Malaysia
| | - Puneet Agarwal
- School of Medicine, International Medical University, Bukit Jalil, Malaysia
| | - Igor Iezhitsa
- School of Medicine, International Medical University, Bukit Jalil, Malaysia
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Intraocular Pressure-Induced Endothelial Dysfunction of Retinal Blood Vessels Is Persistent, but Does Not Trigger Retinal Ganglion Cell Loss. Antioxidants (Basel) 2022; 11:antiox11101864. [PMID: 36290587 PMCID: PMC9598728 DOI: 10.3390/antiox11101864] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/11/2022] [Accepted: 09/15/2022] [Indexed: 12/02/2022] Open
Abstract
Research has been conducted into vascular abnormalities in the pathogenesis of glaucoma, but conclusions remain controversial. Our aim was to test the hypothesis that retinal endothelial dysfunction induced by elevated intraocular pressure (IOP) persists after IOP normalization, further triggering retinal ganglion cell (RGC) loss. High intraocular pressure (HP) was induced in mice by episcleral vein occlusion (EVO). Retinal vascular function was measured via video microscopy in vitro. The IOP, RGC and their axons survival, levels of oxidative stress and inflammation as well as vascular pericytes coverage, were determined. EVO caused HP for two weeks, which returned to baseline afterwards. Mice with HP exhibited endothelial dysfunction in retinal arterioles, reduced density of RGC and their axons, and loss of pericytes in retinal arterioles. Notably, these values were similar to those of mice with recovered IOP (RP). Levels of oxidative stress and inflammation were increased in HP mice but went back to normal in the RP mice. Our data demonstrate that HP induces persistent endothelial dysfunction in retinal arterioles, which persists one month after RP. Oxidative stress, inflammation, and loss of pericytes appear to be involved in triggering vascular functional deficits. Our data also suggest that retinal endothelial dysfunction does not affect RGC and their axon survival.
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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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11
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Retinal ganglion cell loss in an ex vivo mouse model of optic nerve cut is prevented by curcumin treatment. Cell Death Discov 2021; 7:394. [PMID: 34911931 PMCID: PMC8674341 DOI: 10.1038/s41420-021-00760-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 10/27/2021] [Accepted: 11/09/2021] [Indexed: 11/08/2022] Open
Abstract
Retinal ganglion cell (RGC) loss is a pathologic feature common to several retinopathies associated to optic nerve damage, leading to visual loss and blindness. Although several scientific efforts have been spent to understand the molecular and cellular changes occurring in retinal degeneration, an effective therapy to counteract the retinal damage is still not available. Here we show that eyeballs, enucleated with the concomitant optic nerve cut (ONC), when kept in PBS for 24 h showed retinal and optic nerve degeneration. Examining retinas and optic nerves at different time points in a temporal window of 24 h, we found a thinning of some retinal layers especially RGC's layer, observing a powerful RGC loss after 24 h correlated with an apoptotic, MAPKs and degradative pathways dysfunctions. Specifically, we detected a time-dependent increase of Caspase-3, -9 and pro-apoptotic marker levels, associated with a strong reduction of BRN3A and NeuN levels. Importantly, a powerful activation of JNK, c-Jun, and ERK signaling (MAPKs) were observed, correlated with a significant augmented SUMO-1 and UBC9 protein levels. The degradation signaling pathways was also altered, causing a significant decrease of ubiquitination level and an increased LC3B activation. Notably, it was also detected an augmented Tau protein level. Curcumin, a powerful antioxidant natural compound, prevented the alterations of apoptotic cascade, MAPKs, and SUMO-1 pathways and the degradation system, preserving the RGC survival and the retinal layer thickness. This ex vivo retinal degeneration model could be a useful method to study, in a short time window, the effect of neuroprotective tools like curcumin that could represent a potential treatment to contrast retinal cell death.
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12
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Deng W, Hedberg-Buenz A, Soukup DA, Taghizadeh S, Wang K, Anderson MG, Garvin MK. AxonDeep: Automated Optic Nerve Axon Segmentation in Mice With Deep Learning. Transl Vis Sci Technol 2021; 10:22. [PMID: 34932117 PMCID: PMC8709929 DOI: 10.1167/tvst.10.14.22] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Optic nerve damage is the principal feature of glaucoma and contributes to vision loss in many diseases. In animal models, nerve health has traditionally been assessed by human experts that grade damage qualitatively or manually quantify axons from sampling limited areas from histologic cross sections of nerve. Both approaches are prone to variability and are time consuming. First-generation automated approaches have begun to emerge, but all have significant shortcomings. Here, we seek improvements through use of deep-learning approaches for segmenting and quantifying axons from cross-sections of mouse optic nerve. Methods Two deep-learning approaches were developed and evaluated: (1) a traditional supervised approach using a fully convolutional network trained with only labeled data and (2) a semisupervised approach trained with both labeled and unlabeled data using a generative-adversarial-network framework. Results From comparisons with an independent test set of images with manually marked axon centers and boundaries, both deep-learning approaches outperformed an existing baseline automated approach and similarly to two independent experts. Performance of the semisupervised approach was superior and implemented into AxonDeep. Conclusions AxonDeep performs automated quantification and segmentation of axons from healthy-appearing nerves and those with mild to moderate degrees of damage, similar to that of experts without the variability and constraints associated with manual performance. Translational Relevance Use of deep learning for axon quantification provides rapid, objective, and higher throughput analysis of optic nerve that would otherwise not be possible.
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Affiliation(s)
- Wenxiang Deng
- Department of Electrical and Computer Engineering, The University of Iowa, Iowa City, IA, USA.,Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA
| | - Adam Hedberg-Buenz
- Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA.,Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA
| | - Dana A Soukup
- Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA.,Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA
| | - Sima Taghizadeh
- Department of Electrical and Computer Engineering, The University of Iowa, Iowa City, IA, USA
| | - Kai Wang
- Department of Biostatistics, The University of Iowa, Iowa City, IA, USA
| | - Michael G Anderson
- Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA.,Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, IA, USA
| | - Mona K Garvin
- Department of Electrical and Computer Engineering, The University of Iowa, Iowa City, IA, USA.,Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA
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13
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Di Pierdomenico J, Henderson DCM, Giammaria S, Smith VL, Jamet AJ, Smith CA, Hooper ML, Chauhan BC. Age and intraocular pressure in murine experimental glaucoma. Prog Retin Eye Res 2021; 88:101021. [PMID: 34801667 DOI: 10.1016/j.preteyeres.2021.101021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/25/2021] [Accepted: 11/08/2021] [Indexed: 12/23/2022]
Abstract
Age and intraocular pressure (IOP) are the two most important risk factors for the development and progression of open-angle glaucoma. While IOP is commonly considered in models of experimental glaucoma (EG), most studies use juvenile or adult animals and seldom older animals which are representative of the human disease. This paper provides a concise review of how retinal ganglion cell (RGC) loss, the hallmark of glaucoma, can be evaluated in EG with a special emphasis on serial in vivo imaging, a parallel approach used in clinical practice. It appraises the suitability of EG models for the purpose of in vivo imaging and argues for the use of models that provide a sustained elevation of IOP, without compromise of the ocular media. In a study with parallel cohorts of adult (3-month-old, equivalent to 20 human years) and old (2-year-old, equivalent to 70 human years) mice, we compare the effects of elevated IOP on serial ganglion cell complex thickness and individual RGC dendritic morphology changes obtained in vivo. We also evaluate how age modulates the impact of elevated IOP on RGC somal and axonal density in histological analysis as well the density of melanopsin RGCs. We discuss the challenges of using old animals and emphasize the potential of single RGC imaging for understanding the pathobiology of RGC loss and evaluating new therapeutic avenues.
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Affiliation(s)
- Johnny Di Pierdomenico
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Delaney C M Henderson
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Sara Giammaria
- Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Victoria L Smith
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Aliénor J Jamet
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Corey A Smith
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Michele L Hooper
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Balwantray C Chauhan
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada.
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14
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Solar Fernandez V, Marino M, Fiocchetti M. Neuroglobin in Retinal Neurodegeneration: A Potential Target in Therapeutic Approaches. Cells 2021; 10:cells10113200. [PMID: 34831423 PMCID: PMC8621852 DOI: 10.3390/cells10113200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/09/2021] [Accepted: 11/15/2021] [Indexed: 12/12/2022] Open
Abstract
Retinal neurodegeneration affects an increasing number of people worldwide causing vision impairments and blindness, reducing quality of life, and generating a great economic challenge. Due to the complexity of the tissue, and the diversity of retinal neurodegenerative diseases in terms of etiology and clinical presentation, so far, there are no cures and only a few early pathological markers have been identified. Increasing efforts have been made to identify and potentiate endogenous protective mechanisms or to abolish detrimental stress responses to preserve retinal structure and function. The discovering of the intracellular monomeric globin neuroglobin (NGB), found at high concentration in the retina, has opened new possibilities for the treatment of retinal disease. Indeed, the NGB capability to reversibly bind oxygen and its neuroprotective function against several types of insults including oxidative stress, ischemia, and neurodegenerative conditions have raised the interest in the possible role of the globin as oxygen supplier in the retina and as a target for retinal neurodegeneration. Here, we provide the undercurrent knowledge on NGB distribution in retinal layers and the evidence about the connection between NGB level modulation and the functional outcome in terms of retinal neuroprotection to provide a novel therapeutic/preventive target for visual pathway degenerative disease.
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Affiliation(s)
- Virginia Solar Fernandez
- Department of Science, University Roma Tre, Viale G. Marconi, 00146 Rome, Italy; (V.S.F.); (M.M.)
- Neuroendocrinology, Metabolism, and Neuropharmacology Unit, IRCCS Santa Lucia Foundation, 00143 Rome, Italy
| | - Maria Marino
- Department of Science, University Roma Tre, Viale G. Marconi, 00146 Rome, Italy; (V.S.F.); (M.M.)
- Neuroendocrinology, Metabolism, and Neuropharmacology Unit, IRCCS Santa Lucia Foundation, 00143 Rome, Italy
| | - Marco Fiocchetti
- Department of Science, University Roma Tre, Viale G. Marconi, 00146 Rome, Italy; (V.S.F.); (M.M.)
- Neuroendocrinology, Metabolism, and Neuropharmacology Unit, IRCCS Santa Lucia Foundation, 00143 Rome, Italy
- Correspondence: ; Tel.: +39-06-5733-6455; Fax: +39-06-5733-6321
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15
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Kim YK, Kim SN, Min CH, Park M, Kim DW, Ha A, Kim YJ, Choy YB, Park KH. Novel glaucoma model in rats using photo-crosslinked azidobenzoic acid-modified chitosan. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 125:112112. [PMID: 33965116 DOI: 10.1016/j.msec.2021.112112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 03/24/2021] [Accepted: 03/30/2021] [Indexed: 10/21/2022]
Abstract
An experimental model of pressure-induced optic nerve damage promises to greatly expand understanding of the cellular events leading to retinal ganglion cell (RGC) death and of how they are influenced by intraocular pressure (IOP) and other risk factors associated with glaucoma. In this work, we propose a novel strategy employing photo-crosslinkable azidobenzoic acid-modified chitosan (Az-CH) for long-term, persistent elevation of IOP. For this purpose, a solution of Az-CH was injected into the anterior chamber of experimental rat eyes, which were subsequently irradiated with ultraviolet (UV) light to form an Az-CH gel that hindered aqueous outflow and effected prolonged IOP elevation thereby. The control eyes were treated as follows: (1) intracameral injection of Az-CH without UV irradiation, (2) intracameral injection of saline solution without UV irradiation or (3) no injection with UV irradiation. A significant IOP increase was observed in the experimental eyes, which was continuously higher for the whole testing period of 12 weeks after one-time treatment with Az-CH injection and UV irradiation. Also, a more significant loss of RGCs, one of the major features of glaucoma, was observed in experimental eyes than in the control eyes. Therefore, the strategy presented herein can be a novel experimental model to study the mechanism of RGC damage by elevated IOP over the course of a prolonged period.
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Affiliation(s)
- Young Kook Kim
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Ophthalmology, Seoul National University Hospital, Seoul, Republic of Korea
| | - Se-Na Kim
- Institute of Medical & Biological Engineering, Medical Research Center, Seoul National University, Seoul, Republic of Korea
| | - Chang Hee Min
- Interdisciplinary Program in Bioengineering, College of Engineering, Seoul National University, Seoul, Republic of Korea
| | - Min Park
- Interdisciplinary Program in Bioengineering, College of Engineering, Seoul National University, Seoul, Republic of Korea
| | - Dai Woo Kim
- Department of Ophthalmology, Kyungpook National University Hospital, Daegu, Republic of Korea; Department of Ophthalmology, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Ahnul Ha
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Ophthalmology, Jeju National University Hospital, Jeju-si, Republic of Korea; Department of Ophthalmology, Jeju National University School of Medicine, Jeju-si, Republic of Korea
| | - Yu Jeong Kim
- Department of Ophthalmology, Seoul National University Hospital, Seoul, Republic of Korea
| | - Young Bin Choy
- Institute of Medical & Biological Engineering, Medical Research Center, Seoul National University, Seoul, Republic of Korea; Interdisciplinary Program in Bioengineering, College of Engineering, Seoul National University, Seoul, Republic of Korea; Department of Biomedical Engineering, Seoul National University College of Medicine, Seoul, Republic of Korea.
| | - Ki Ho Park
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Ophthalmology, Seoul National University Hospital, Seoul, Republic of Korea.
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16
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Wong VHY, Zhao D, Bui BV, Millar CJ, Nguyen CTO. Increased episcleral venous pressure in a mouse model of circumlimbal suture induced ocular hypertension. Exp Eye Res 2020; 202:108348. [PMID: 33166503 DOI: 10.1016/j.exer.2020.108348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 10/29/2020] [Accepted: 11/03/2020] [Indexed: 11/30/2022]
Abstract
PURPOSE To investigate changes in aqueous humor dynamics during intraocular pressure (IOP) elevation induced by circumlimbal suture in mice. METHODS Ocular hypertension (OHT) was induced by applying a circumlimbal suture behind the limbus in male adult C57BL6/J mice. In the OHT group, the suture was left in place for an average of 8 weeks (n = 10, OHT group). In the sham control group the suture was cut at 2 days (n = 9, sham group) and in the naïve control group (n = 5) no suture was implanted. IOP was measured at baseline across 3 days, 1 h post-suture implantation, and at the chronic endpoint. Anterior segments were assessed using optical coherence tomography (OCT). Episcleral venous pressure (EVP), total outflow facility (C), uveoscleral outflow (Fu) and aqueous humor flow rate (Fin) were determined using a constant-flow infusion model. RESULTS All aqueous dynamic and chronic IOP outcome measures showed no difference between sham and naïve controls (p > 0.05) and thus these groups were combined into a single control group. IOP was elevated in OHT group compared with controls (p < 0.01). Chronic suture implantation did not change pupil size, anterior chamber depth or iridocorneal angles (p > 0.05). EVP was significantly higher in OHT eyes compared to control eyes (p < 0.01). There was no statistical difference in C, Fu and Fin between groups (p > 0.05). A significant linear correlation was found between IOP and EVP (R2 = 0.35, p = 0.001). CONCLUSIONS Circumlimbal suture implantation in mouse eyes results in chronic IOP elevation without angle closure. Chronic IOP elevation is likely to reflect higher EVP.
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Affiliation(s)
- Vickie H Y Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Da Zhao
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Cameron J Millar
- North Texas Eye Research Institute, Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Christine T O Nguyen
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.
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17
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Peripheral Latanoprost Administration Lowers Intraocular Pressure in the Wistar Rat. Ophthalmol Ther 2020; 9:1-8. [PMID: 32383108 PMCID: PMC7406633 DOI: 10.1007/s40123-020-00256-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Indexed: 01/20/2023] Open
Abstract
Purpose Instillation of latanoprost eye drops into the conjunctival sac to lower
intraocular pressure (IOP) is the most frequently used treatment for primary
open-angle glaucoma. The aim of this study was to evaluate the influence of
latanoprost on IOP in the rat when applied peripherally. Methods A rodent-dedicated tonometer was used to measure IOP in conscious adult
male normotensive Wistar rats habituated to the measurement procedure. Commercially
available 0.005% latanoprost solutions were continuously delivered to the periphery
of the eye over 7 days using mini-pumps inserted subcutaneously in the animal’s back,
and IOP was measured daily. For comparison, a solution containing an equimolar
concentration of latanoprost acid, an active compound of latanoprost, was similarly
infused into the eyes of different Wistar rats. Results Continuous subcutaneous infusion of latanoprost gradually decreased the
IOP; the stable nadir of IOP, which was 20% lower than that prior to the start of
infusion, was reached on day 3. The effect was statistically significant and fully
reversed 2 days after cessation of drug delivery. Continuous subcutaneous application
of the solution containing an equimolar amount of latanoprost acid did not
appreciably influence the IOP. Conclusion Subcutaneous continuous delivery of latanoprost decreased the IOP in the
conscious normotensive Wistar rats in this study. If this effect is confirmed in
humans, it may open the possibility of using peripheral systems of drug delivery,
which could significantly improve patient compliance.
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18
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Zhang J, Fang F, Li L, Huang H, Webber HC, Sun Y, Mahajan VB, Hu Y. A Reversible Silicon Oil-Induced Ocular Hypertension Model in Mice. J Vis Exp 2019. [PMID: 31789319 DOI: 10.3791/60409] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Elevated intraocular pressure (IOP) is a well-documented risk factor for glaucoma. Here we describe a novel, effective method for consistently inducing stable IOP elevation in mice that mimics the post-operative complication of using silicone oil (SO) as a tamponade agent in human vitreoretinal surgery. In this protocol, SO is injected into the anterior chamber of the mouse eye to block the pupil and prevent inflow of aqueous humor. The posterior chamber accumulates aqueous humor and this in turn increases the IOP of the posterior segment. A single SO injection produces reliable, sufficient, and stable IOP elevation, which induces significant glaucomatous neurodegeneration. This model is a true replicate of secondary glaucoma in the eye clinic. To further mimic the clinical setting, SO can be removed from the anterior chamber to reopen the drainage pathway and allow inflow of aqueous humor, which is drained through the trabecular meshwork (TM) at the angle of the anterior chamber. Because IOP quickly returns to normal, the model can be used to test the effect of lowering IOP on glaucomatous retinal ganglion cells. This method is straightforward, does not require special equipment or repeat procedures, closely simulates clinical situations, and may be applicable to diverse animal species. However, minor modifications may be required.
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Affiliation(s)
- Jie Zhang
- Department of Ophthalmology, Stanford University School of Medicine; Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology
| | - Fang Fang
- Department of Ophthalmology, Stanford University School of Medicine; Department of Ophthalmology, Second Xiangya Hospital of Central South University
| | - Liang Li
- Department of Ophthalmology, Stanford University School of Medicine
| | - Haoliang Huang
- Department of Ophthalmology, Stanford University School of Medicine
| | - Hannah C Webber
- Department of Ophthalmology, Stanford University School of Medicine
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine; Department of Ophthalmology, Veterans Affairs Palo Alto Health Care
| | - Vinit B Mahajan
- Department of Ophthalmology, Stanford University School of Medicine; Department of Ophthalmology, Veterans Affairs Palo Alto Health Care
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine;
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Koschade SE, Koch MA, Braunger BM, Tamm ER. Efficient determination of axon number in the optic nerve: A stereological approach. Exp Eye Res 2019; 186:107710. [PMID: 31254512 DOI: 10.1016/j.exer.2019.107710] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 05/26/2019] [Accepted: 06/21/2019] [Indexed: 11/26/2022]
Abstract
Quantifying the number of axons in the optic nerve is of interest in many research questions. Here, we show that a stereological method allows simple, efficient, precise and unbiased determination of the total axon number in the murine optic nerve. Axons in semi-thin optic nerve cross sections from untreated eyes (n = 21) and eyes subjected to retinal damage by intravitreous NMDA injections (n = 32) or PBS controls (n = 5) were manually identified, counted and digitally labeled by hand. A stereological procedure was empirically tested with systematic combinations of different sampling methods (simple random sampling without replacement, systematic uniform random sampling, stratified random sampling) and sampling parameters. Extensive numerical Monte Carlo experiments were performed to evaluate their large-sample properties. Our results demonstrate reliable determination of total axon number and superior performance compared to other methods at a small fraction of the time required for a full manual count. We specify suitable sampling parameters for the adoption of an efficient stereological sampling scheme, give empirical estimates of the additionally introduced sampling variance to facilitate experimental planning, and offer AxonCounter, an easy-to-use plugin implementing these stereological methods for the multi-platform image processing application NIH ImageJ.
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Affiliation(s)
- Sebastian E Koschade
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany.
| | - Marcus A Koch
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
| | - Barbara M Braunger
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany; Institute of Anatomy and Cell Biology, Julius-Maximilians-University of Würzburg, Würzburg, Germany
| | - Ernst R Tamm
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany.
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20
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Reinhard J, Wiemann S, Joachim SC, Palmhof M, Woestmann J, Denecke B, Wang Y, Downey GP, Faissner A. Heterozygous Meg2 Ablation Causes Intraocular Pressure Elevation and Progressive Glaucomatous Neurodegeneration. Mol Neurobiol 2019; 56:4322-4345. [PMID: 30315478 DOI: 10.1007/s12035-018-1376-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 09/28/2018] [Indexed: 02/07/2023]
Abstract
Glaucomatous neurodegeneration represents one of the major causes of irreversible blindness worldwide. Yet, the detailed molecular mechanisms that initiate optic nerve damage and retinal ganglion cell (RGC) loss are not fully understood. Members of the protein tyrosine phosphatase (PTP) superfamily are key players in numerous neurodegenerative diseases. In order to investigate the potential functional relevance of the PTP megakaryocyte 2 (Meg2) in retinal neurodegeneration, we analyzed Meg2 knockout (KO) and heterozygous (HET)-synonym protein-tyrosine phosphatase non-receptor type 9 (Ptpn9)-mice. Interestingly, via global microarray and quantitative real-time PCR (RT-qPCR) analyses of Meg2 KO and HET retinae, we observed a dysregulation of several candidate genes that are highly associated with retinal degeneration and intraocular pressure (IOP) elevation, the main risk factor for glaucoma. Subsequent IOP measurements in Meg2 HET mice verified progressive age-dependent IOP elevation. Ultrastructural analyses and immunohistochemistry showed severe optic nerve degeneration accompanied by a dramatic loss of RGCs. Additionally, HET mice displayed reactive micro-/macrogliosis and early activation of the classical complement cascade with pronounced deposition of the membrane attack complex (MAC) in the retina and optic nerve. When treated with latanoprost, significant IOP lowering prevented RGC loss and microglial invasion in HET mice. Finally, electroretinogram (ERG) recordings revealed reduced a- and b-wave amplitudes, indicating impaired retinal functionality in Meg2 HET mice. Collectively, our findings indicate that the heterozygous loss of Meg2 in mice is sufficient to cause IOP elevation and glaucomatous neurodegeneration. Thus, Meg2 HET mice may serve as a novel animal model to study the pathomechanism involved in the onset and progression of glaucoma.
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Affiliation(s)
- Jacqueline Reinhard
- Department of Cell Morphology and Molecular Neurobiology, NDEF 05/594, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstrasse 150, 44780, Bochum, Germany
| | - Susanne Wiemann
- Department of Cell Morphology and Molecular Neurobiology, NDEF 05/594, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstrasse 150, 44780, Bochum, Germany
| | - Stephanie C Joachim
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - Marina Palmhof
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - Julia Woestmann
- Department of Cell Morphology and Molecular Neurobiology, NDEF 05/594, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstrasse 150, 44780, Bochum, Germany
| | - Bernd Denecke
- Interdisciplinary Centre for Clinical Research, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Yingchun Wang
- Division of Respirology, Department of Medicine, University of Toronto and Toronto General Hospital Research Institute of the University Health Network, 610 University Avenue, Toronto, ON, M5S 1A8, Canada
| | - Gregory P Downey
- Division of Pulmonary Sciences and Critical Care Medicine, Departments of Medicine and Immunology and Microbiology, University of Colorado, Aurora, CO, 80045, USA
- Division of Pulmonary, Critical Care and Sleep Medicine, Departments of Medicine, Pediatrics and Biomedical Research, National Jewish Health, 1400 Jackson Street, Denver, CO, 80206, USA
| | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, NDEF 05/594, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstrasse 150, 44780, Bochum, Germany.
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21
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Zhang J, Li L, Huang H, Fang F, Webber HC, Zhuang P, Liu L, Dalal R, Tang PH, Mahajan VB, Sun Y, Li S, Zhang M, Goldberg JL, Hu Y. Silicone oil-induced ocular hypertension and glaucomatous neurodegeneration in mouse. eLife 2019; 8:45881. [PMID: 31090540 PMCID: PMC6533060 DOI: 10.7554/elife.45881] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 05/14/2019] [Indexed: 02/06/2023] Open
Abstract
Understanding the molecular mechanism of glaucoma and development of neuroprotectants is significantly hindered by the lack of a reliable animal model that accurately recapitulates human glaucoma. Here, we sought to develop a mouse model for the secondary glaucoma that is often observed in humans after silicone oil (SO) blocks the pupil or migrates into the anterior chamber following vitreoretinal surgery. We observed significant intraocular pressure (IOP) elevation after intracameral injection of SO, and that SO removal allows IOP to return quickly to normal. This simple, inducible and reversible mouse ocular hypertension model shows dynamic changes of visual function that correlate with progressive retinal ganglion cell (RGC) loss and axon degeneration. It may be applicable with only minor modifications to a range of animal species in which it will generate stable, robust IOP elevation and significant neurodegeneration that will facilitate selection of neuroprotectants and investigating the pathogenesis of ocular hypertension-induced glaucoma.
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Affiliation(s)
- Jie Zhang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States.,Department of Ophthalmology, Tongji Medical College, Union Hospital, Huazhong University of Science & Technology, Wuhan, China
| | - Liang Li
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Haoliang Huang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Fang Fang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States.,Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Hannah C Webber
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Pei Zhuang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Liang Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Peter H Tang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States.,Department of Ophthalmology, Veterans Affairs Palo Alto Health Care, Palo Alto, United States
| | - Vinit B Mahajan
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States.,Department of Ophthalmology, Veterans Affairs Palo Alto Health Care, Palo Alto, United States
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States.,Department of Ophthalmology, Veterans Affairs Palo Alto Health Care, Palo Alto, United States
| | - Shaohua Li
- Department of Ophthalmology, Tongji Medical College, Union Hospital, Huazhong University of Science & Technology, Wuhan, China
| | - Mingchang Zhang
- Department of Ophthalmology, Tongji Medical College, Union Hospital, Huazhong University of Science & Technology, Wuhan, China
| | - Jeffrey L Goldberg
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, United States
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22
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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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23
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Ficarrotta KR, Bello SA, Mohamed YH, Passaglia CL. Aqueous Humor Dynamics of the Brown-Norway Rat. Invest Ophthalmol Vis Sci 2019; 59:2529-2537. [PMID: 29847660 PMCID: PMC5967599 DOI: 10.1167/iovs.17-22915] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The study aimed to provide a quantitative description of aqueous humor dynamics in healthy rat eyes. Methods One eye of 26 anesthetized adult Brown-Norway rats was cannulated with a needle connected to a perfusion pump and pressure transducer. Pressure-flow data were measured in live and dead eyes by varying pump rate (constant-flow technique) or by modulating pump duty cycle to hold intraocular pressure (IOP) at set levels (modified constant-pressure technique). Data were fit by the Goldmann equation to estimate conventional outflow facility (\begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}C\end{document}) and unconventional outflow rate (\begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}{F_{un}}\end{document}). Parameter estimates were respectively checked by inserting a shunt of similar conductance into the eye and by varying eye hydration methodology. Results Rat IOP averaged 14.6 ± 1.9 mm Hg at rest. Pressure-flow data were repeatable and indistinguishable for the two perfusion techniques, yielding \begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}C\end{document} = 0.023 ± 0.002 μL/min/mm Hg and \begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}{F_{un}}\end{document} = 0.096 ± 0.024 μL/min. \begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}C\end{document} was similar for live and dead eyes and increased upon shunt insertion by an amount equal to shunt conductance, validating measurement accuracy. At 100% humidity \begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}{F_{un}}\end{document} dropped to 0.003 ± 0.030 μL/min. Physiological washout was not observed (−0.35 ± 0.65%/h), and trabecular anatomy looked normal. Conclusions Rat aqueous humor dynamics are intermediate in magnitude compared to those in mice and humans, consistent with species differences in eye size. \begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}C\end{document} does not change with time or death. Evaporation complicates measurement of \begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}{F_{un}}\end{document} even when eyes are not enucleated. Absence of washout is a notable finding seen only in mouse and human eyes to date.
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Affiliation(s)
- Kayla R Ficarrotta
- Chemical and Biomedical Engineering Department, University of South Florida, Tampa, Florida, United States
| | - Simon A Bello
- Electrical Engineering Department, University of South Florida, Tampa, Florida, United States
| | - Youssef H Mohamed
- Chemical and Biomedical Engineering Department, University of South Florida, Tampa, Florida, United States
| | - Christopher L Passaglia
- Chemical and Biomedical Engineering Department, University of South Florida, Tampa, Florida, United States.,Ophthalmology Department, University of South Florida, Tampa, Florida, United States
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24
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Kuehn S, Meißner W, Grotegut P, Theiss C, Dick HB, Joachim SC. Intravitreal S100B Injection Leads to Progressive Glaucoma Like Damage in Retina and Optic Nerve. Front Cell Neurosci 2018; 12:312. [PMID: 30319357 PMCID: PMC6169322 DOI: 10.3389/fncel.2018.00312] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/28/2018] [Indexed: 12/15/2022] Open
Abstract
The glial protein S100B, which belongs to a calcium binding protein family, is up-regulated in neurological diseases, like multiple sclerosis or glaucoma. In previous studies, S100B immunization led to retinal ganglion cell (RGC) loss in an experimental autoimmune glaucoma (EAG) model. Now, the direct degenerative impact of S100B on the retina and optic nerve was evaluated. Therefore, 2 μl of S100B was intravitreally injected in two concentrations (0.2 and 0.5 μg/μl). At day 3, 14 and 21, retinal neurons, such as RGCs, amacrine and bipolar cells, as well as apoptotic mechanisms were analyzed. Furthermore, neurofilaments, myelin fibers and axons of optic nerves were evaluated. In addition, retinal function and immunoglobulin G (IgG) level in the serum were measured. At day 3, RGCs were unaffected in the S100B groups, when compared to the PBS group. Later, at days 14 and 21, the RGC number as well as the β-III tubulin protein level was reduced in the S100B groups. Only at day 14, active apoptotic mechanisms were noted. The number of amacrine cells was first affected at day 21, while the bipolar cell amount remained comparable to the PBS group. Also, the optic nerve neurofilament structure was damaged from day 3 on. At day 14, numerous swollen axons were observed. The intraocular injection of S100B is a new model for a glaucoma like degeneration. Although the application site was the eye, the optic nerve degenerated first, already at day 3. From day 14 on, retinal damage and loss of function was noted. The RGCs in the middle part of the retina were first affected. At day 21, the damage expanded and RGCs had degenerated in all areas of the retina as well as amacrine cells. Furthermore, elevated IgG levels in the serum were measured at day 21, which could be a sign of a late and S100B independet immune response. In summary, S100B had a direct destroying impact on the axons of the optic nerve. The damage of the retinal cell bodies seems to be a consequence of this axon loss.
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Affiliation(s)
- Sandra Kuehn
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Wilhelm Meißner
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Pia Grotegut
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Carsten Theiss
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
| | - H Burkhard Dick
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Stephanie C Joachim
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
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25
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Pardue MT, Allen RS. Neuroprotective strategies for retinal disease. Prog Retin Eye Res 2018; 65:50-76. [PMID: 29481975 PMCID: PMC6081194 DOI: 10.1016/j.preteyeres.2018.02.002] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/14/2018] [Accepted: 02/20/2018] [Indexed: 12/20/2022]
Abstract
Diseases that affect the eye, including photoreceptor degeneration, diabetic retinopathy, and glaucoma, affect 11.8 million people in the US, resulting in vision loss and blindness. Loss of sight affects patient quality of life and puts an economic burden both on individuals and the greater healthcare system. Despite the urgent need for treatments, few effective options currently exist in the clinic. Here, we review research on promising neuroprotective strategies that promote neuronal survival with the potential to protect against vision loss and retinal cell death. Due to the large number of neuroprotective strategies, we restricted our review to approaches that we had direct experience with in the laboratory. We focus on drugs that target survival pathways, including bile acids like UDCA and TUDCA, steroid hormones like progesterone, therapies that target retinal dopamine, and neurotrophic factors. In addition, we review rehabilitative methods that increase endogenous repair mechanisms, including exercise and electrical stimulation therapies. For each approach, we provide background on the neuroprotective strategy, including history of use in other diseases; describe potential mechanisms of action; review the body of research performed in the retina thus far, both in animals and in humans; and discuss considerations when translating each treatment to the clinic and to the retina, including which therapies show the most promise for each retinal disease. Despite the high incidence of retinal diseases and the complexity of mechanisms involved, several promising neuroprotective treatments provide hope to prevent blindness. We discuss attractive candidates here with the goal of furthering retinal research in critical areas to rapidly translate neuroprotective strategies into the clinic.
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Affiliation(s)
- Machelle T Pardue
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, 1670 Clairmont Road, Decatur, GA, 30033, USA; Department of Biomedical Engineering, Georgia Institute of Technology, 313 Ferst Drive, Atlanta, GA, 30332, USA.
| | - Rachael S Allen
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, 1670 Clairmont Road, Decatur, GA, 30033, USA
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26
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Guo C, Qu X, Rangaswamy N, Leehy B, Xiang C, Rice D, Prasanna G. A murine glaucoma model induced by rapid in vivo photopolymerization of hyaluronic acid glycidyl methacrylate. PLoS One 2018; 13:e0196529. [PMID: 29949582 PMCID: PMC6021085 DOI: 10.1371/journal.pone.0196529] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 04/13/2018] [Indexed: 12/04/2022] Open
Abstract
Glaucoma is an optic neuropathy commonly associated with elevated intraocular pressure (IOP) resulting in progressive loss of retinal ganglion cells (RGCs) and optic nerve degeneration, leading to blindness. New therapeutic approaches that better preserve the visual field by promoting survival and health of RGCs are highly needed since RGC death occurs despite good IOP control in glaucoma patients. We have developed a novel approach to reliably induce chronic IOP elevation in mouse using a photopolymerizable biomatrix, hyaluronic acid glycidyl methacrylate. This is achieved by rapid in vivo crosslinking of the biomatrix at the iridocorneal angle by a flash of ultraviolet A (UVA) light to impede the aqueous outflow pathway with a controllable manner. Sustained IOP elevation was induced after a single manipulation and was maintained at ~45% above baseline for >4 weeks. Significant thinning of the inner retina and ~35% reduction in RGCs and axons was noted within one month of IOP elevation. Optic nerve degeneration showed positive correlation with cumulative IOP elevation. Activation of astrocytes and microglia appeared to be an early event in response to IOP elevation preceding detectable RGC and axon loss. Attenuated glial reactivity was noted at later stage where significant RGC/axon loss had occurred suggesting astrocytes and microglia may play different roles over the course of glaucomatous degeneration. This novel murine glaucoma model is reproducible and displays cellular changes that recapitulate several pathophysiological features of glaucoma.
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Affiliation(s)
- Chenying Guo
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
- * E-mail: (GP); (CG)
| | - Xin Qu
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Nalini Rangaswamy
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Barrett Leehy
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Chuanxi Xiang
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Dennis Rice
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Ganesh Prasanna
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
- * E-mail: (GP); (CG)
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27
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Huang W, Hu F, Wang M, Gao F, Xu P, Xing C, Sun X, Zhang S, Wu J. Comparative analysis of retinal ganglion cell damage in three glaucomatous rat models. Exp Eye Res 2018; 172:112-122. [PMID: 29605491 DOI: 10.1016/j.exer.2018.03.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/21/2018] [Accepted: 03/19/2018] [Indexed: 10/17/2022]
Abstract
Progressive retinal ganglion cell (RGC) death is the major cause of retinal nerve fiber layer thinning and visual field defects in glaucoma. The purpose of this study was to compare RGC damage in three commonly used glaucomatous rat models. These models were generated by (i) injection of paramagnetic microbeads into the anterior chamber; (ii) cauterization of three episcleral veins of the eye (EVC); and (iii) intravitreal injection of N-Methyl-D-Aspartate (NMDA). Intraocular pressure (IOP) was measured with a rebound tonometer at 6, 12, and 18 h; 1, 3, and 5 days; and 1, 2, 3, 4, 6, and 8 weeks. We measured the RGC density of the three glaucomatous models in the flat-mounted retina by immunofluorescence. Subsequently, the thicknesses of both retinal ganglion cell layer (GCL) and inner retinal layer (IRL) were analyzed by hematoxylin and eosin staining of retinal sections. The visual functional deterioration was evaluated by measurement of the photopic negative response (PhNR) of different models. The IOP averages during three weeks were 22.35 ± 1.23 mmHg (mean ± SD), 20.91 ± 1.97 mmHg, and 9.67 ± 0.42 mmHg, with 50.2%, 44.00% and 66.76% RGC loss by 8 weeks, respectively, in the microbead group, EVC group and NMDA group. Decreased thickness in the GCL was observed in all three groups, while the thickness of IRL and ONL was decreased in the EVC and NMDA groups. Significant positive correlation of RGC loss rate with ΔIOP integral were demonstrated in both microbead and EVC models. Moreover, we found that the PhNR amplitudes declined early by the first day in the NMDA group, 5 days later in the EVC group and by 7 days in the microbead group. Each glaucomatous rat model has its strength and weakness. Our study provides detailed data for choosing suitable animal models to advance glaucoma research.
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Affiliation(s)
- Wanjing Huang
- From the Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Fangyuan Hu
- From the Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China; State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China; Key Laboratory of Myopia, Ministry of Health, Shanghai, China
| | - Min Wang
- From the Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Fengjuan Gao
- From the Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Ping Xu
- From the Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China; State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China; Key Laboratory of Myopia, Ministry of Health, Shanghai, China
| | - Chao Xing
- From the Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China; State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China; Key Laboratory of Myopia, Ministry of Health, Shanghai, China
| | - Xinghuai Sun
- From the Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China; State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China; Key Laboratory of Myopia, Ministry of Health, Shanghai, China
| | - Shenghai Zhang
- From the Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China; State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China; Key Laboratory of Myopia, Ministry of Health, Shanghai, China.
| | - Jihong Wu
- From the Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China; State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China; Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China; Key Laboratory of Myopia, Ministry of Health, Shanghai, China.
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Dai M, Zhang Q, Zheng Z, Wang J. Retinal ganglion cell-conditioned medium and surrounding pressure alters gene expression and differentiation of rat retinal progenitor cells. Mol Med Rep 2018; 17:7177-7183. [PMID: 29568879 PMCID: PMC5928676 DOI: 10.3892/mmr.2018.8738] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 12/04/2017] [Indexed: 12/13/2022] Open
Abstract
Loss of retinal ganglion cells is implicated in glaucoma and high intraocular pressure. Factors that affect the differentiation of retinal progenitor cells into retinal ganglion cells remain unclear. The present study aimed to investigate the effects of retinal ganglion cell‑conditioned medium on gene expression and differentiation in retinal progenitor cells, and the effects of surrounding pressure on the survival and differentiation of retinal progenitor cells. Retinal progenitor cells and retinal ganglion cells were isolated from rats. Immunofluorescence staining of Nestin and Thy1 was performed to identify rat retinal progenitor cells and retinal ganglion cells, respectively. Retinal progenitor cells and ganglion cells were cultured for 48 h under surrounding pressure of 0, 20, 40, 60 and 80 mmHg. Cellular apoptosis was detected using a caspase‑3 assay kit. In addition, the culture supernatant of rat retinal ganglion cells was collected. Retinal progenitor cells were cultured in the presence or absence of retinal ganglion‑conditioned medium for 72 h under normal pressure. Gene expression of Nestin, paired box protein 6 (PAX6), Thy1 and brain‑specific homeobox/POU domain protein 3 (Brn‑3) in retinal progenitor cells was detected by reverse transcription‑quantitative polymerase chain reaction. Retinal progenitor cells were cultured in retinal ganglion‑conditioned medium for 72 h under surrounding pressure of 0 and 40 mmHg, respectively, and flow cytometry was utilized to evaluate the effects of pressure on the differentiation of retinal progenitor cells into retinal ganglion cells. The results demonstrated that isolated retinal progenitor cells were Nestin‑positive and retinal ganglion cells were Thy1‑positive, suggesting successful isolation. The activity of caspase‑3 increased in retinal progenitor cells and retinal ganglion cells in a pressure‑dependent manner. When the surrounding pressure reached 40, 60 and 80 mmHg, the activity of caspase‑3 in retinal progenitor cells and ganglion cells increased significantly compared with cells that were not under pressure. Compared with retinal progenitor cells cultured without ganglion‑conditioned medium, those cultured with ganglion‑conditioned medium had significantly decreased expression levels of Nestin and PAX6, and increased expression levels of Thy1 and Brn3. Compared with 0 mmHg pressure, retinal progenitor cells cultured in ganglion‑conditioned medium under 40 mmHg pressure had increased percentages of Thy1‑positive cells. In conclusion, the apoptosis of rat retinal progenitor cells and retinal ganglion cells was pressure‑dependent. Retinal ganglion cell‑conditioned medium increased the differentiation of retinal progenitor cells into retinal ganglion‑like cells, and the differentiation increased as surrounding pressure increased. Current study provides insights that may contribute to the efforts of developing a treatment for glaucoma.
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Affiliation(s)
- Min Dai
- Department of Ophthalmology, Second People's Hospital of Yunnan Province, Kunming, Yunan 650021, P.R. China
| | - Qing Zhang
- Department of Ophthalmology, Second People's Hospital of Yunnan Province, Kunming, Yunan 650021, P.R. China
| | - Zhikun Zheng
- Department of Ophthalmology, Second People's Hospital of Yunnan Province, Kunming, Yunan 650021, P.R. China
| | - Jianzhou Wang
- Department of Ophthalmology, Yan'an Hospital, Kunming, Yunan 650051, P.R. China
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Sharif NA. iDrugs and iDevices Discovery Research: Preclinical Assays, Techniques, and Animal Model Studies for Ocular Hypotensives and Neuroprotectants. J Ocul Pharmacol Ther 2018; 34:7-39. [PMID: 29323613 DOI: 10.1089/jop.2017.0125] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Discovery ophthalmic research is centered around delineating the molecular and cellular basis of ocular diseases and finding and exploiting molecular and genetic pathways associated with them. From such studies it is possible to determine suitable intervention points to address the disease process and hopefully to discover therapeutics to treat them. An investigational new drug (IND) filing for a new small-molecule drug, peptide, antibody, genetic treatment, or a device with global health authorities requires a number of preclinical studies to provide necessary safety and efficacy data. Specific regulatory elements needed for such IND-enabling studies are beyond the scope of this article. However, to enhance the overall data packages for such entities and permit high-quality foundation-building publications for medical affairs, additional research and development studies are always desirable. This review aims to provide examples of some target localization/verification, ocular drug discovery processes, and mechanistic and portfolio-enhancing exploratory investigations for candidate drugs and devices for the treatment of ocular hypertension and glaucomatous optic neuropathy (neurodegeneration of retinal ganglion cells and their axons). Examples of compound screening assays, use of various technologies and techniques, deployment of animal models, and data obtained from such studies are also presented.
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Affiliation(s)
- Najam A Sharif
- 1 Global Alliances & External Research , Santen Incorporated, Emeryville, California.,2 Department of Pharmaceutical Sciences, Texas Southern University , Houston, Texas.,3 Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center , Fort Worth, Texas
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Calkins DJ, Lambert WS, Formichella CR, McLaughlin WM, Sappington RM. The Microbead Occlusion Model of Ocular Hypertension in Mice. Methods Mol Biol 2018; 1695:23-39. [PMID: 29190015 DOI: 10.1007/978-1-4939-7407-8_3] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glaucoma is a common optic neuropathy that leads to vision loss through the degeneration of retinal ganglion cells (RGCs) and their axons. RGC degeneration in glaucoma is associated with sensitivity to intraocular pressure (IOP) and elevated IOP (also known as ocular hypertension) is the primary modifiable risk factor. Ocular hypertension is the primary characteristic of rodent models for glaucoma research. Intracameral injection of microbeads has evolved as a preferred method of IOP elevation in rodents, particularly in mice. Here, we outline the protocol and method for the Microbead Occlusion Model in mice. We highlight the importance of anesthesia choice and the utilization of glass micropipettes in combination with a micromanipulator and microsyringe pump for the successful execution of the model.
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Affiliation(s)
- David J Calkins
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232, USA. .,Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA.
| | - Wendi S Lambert
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Cathryn R Formichella
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - William M McLaughlin
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Rebecca M Sappington
- The Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN, 37232, USA. .,Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA. .,Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA.
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31
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Morrison JC, Johnson EC, Cepurna WO. Hypertonic Saline Injection Model of Experimental Glaucoma in Rats. Methods Mol Biol 2018; 1695:11-21. [PMID: 29190014 DOI: 10.1007/978-1-4939-7407-8_2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A reliable method of creating chronic elevation of intraocular pressure (IOP) in rodents is an important tool in reproducing and studying the mechanisms of optic nerve injury that occur in glaucoma. In addition, such a model could provide a valuable method for testing potential neuroprotective treatments. This paper outlines the basic methods for producing obstruction of aqueous humor outflow and IOP elevation by injecting hypertonic saline (a sclerosant) into the aqueous outflow pathway. This is one of several rodent glaucoma models in use today. In this method, a plastic ring is placed around the equator of the eye to restrict injected saline to the limbus. By inserting a small glass microneedle in an aqueous outflow vein in the episclera and injecting hypertonic saline toward the limbus, the saline is forced into Schlemm's canal and across the trabecular meshwork. The resultant inflammation and scarring of the anterior chamber angle occurs gradually, resulting in a rise in IOP after approximately 1 week. This article will describe the equipment necessary for producing this model and the steps of the technique itself.
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Affiliation(s)
- John C Morrison
- Casey Eye Institute, Oregon Health and Science University, 3375 S.W. Terwilliger Blvd, Portland, OR, 97239, USA.
| | - Elaine C Johnson
- Casey Eye Institute, Oregon Health and Science University, 3375 S.W. Terwilliger Blvd, Portland, OR, 97239, USA
| | - William O Cepurna
- Casey Eye Institute, Oregon Health and Science University, 3375 S.W. Terwilliger Blvd, Portland, OR, 97239, USA
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Liu HH, Zhang L, Shi M, Chen L, Flanagan JG. Comparison of laser and circumlimbal suture induced elevation of intraocular pressure in albino CD-1 mice. PLoS One 2017; 12:e0189094. [PMID: 29190824 PMCID: PMC5708743 DOI: 10.1371/journal.pone.0189094] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 11/18/2017] [Indexed: 12/23/2022] Open
Abstract
Animal models of ocular hypertension are important tools for glaucoma studies. Both acute transient models and chronic models of ocular hypertension may be useful to investigate specific aspects of neurodegeneration. In this study, we compare the intraocular pressure (IOP) and inner retinal changes induced by 1) laser photocoagulation of both episcleral veins and limbal vessels and 2) circumlimbal suture in CD-1 mice. The suture group is divided into 3 subgroups depending on the level of the immediate IOP spike (acute > 55 mmHg or chronic < 55 mmHg) and time period of monitoring (7 or 28 days). The laser group is followed for 7 days. IOP data show that it peaks at 5 hours and returns to normal level within 7 days in the laser group. In all suture groups, IOP spikes initially and decreases gradually, but it remains significantly elevated at 7 days. In 7 days, the acute suture model generates rapid loss of retinal nerve fiber layer (RNFL) and retinal ganglion cells (RGCs) when compared to the gradual loss by the chronic suture model, possibly due to retinal ischemia and reperfusion within the first few hours after treatment. The laser model falls between the acute suture and chronic suture models resulting in less RNFL and RGC loss than the acute suture model but significantly more loss than the chronic suture model. These results suggest that when using suture models of IOP elevation, it is critical to take the initial IOP spike into consideration and to choose between the acute and chronic models depending on respective research purposes.
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Affiliation(s)
- Hsin-Hua Liu
- School of Optometry and Vision Science, University of California, Berkeley, California, United States of America
- Center for Eye Disease and Development, Vision Science Graduate Program, University of California, Berkeley, California, United States of America
- * E-mail:
| | - Liwei Zhang
- School of Optometry and Vision Science, University of California, Berkeley, California, United States of America
- Center for Eye Disease and Development, Vision Science Graduate Program, University of California, Berkeley, California, United States of America
| | - Meng Shi
- School of Optometry and Vision Science, University of California, Berkeley, California, United States of America
- Center for Eye Disease and Development, Vision Science Graduate Program, University of California, Berkeley, California, United States of America
| | - Lu Chen
- School of Optometry and Vision Science, University of California, Berkeley, California, United States of America
- Center for Eye Disease and Development, Vision Science Graduate Program, University of California, Berkeley, California, United States of America
| | - John G. Flanagan
- School of Optometry and Vision Science, University of California, Berkeley, California, United States of America
- Center for Eye Disease and Development, Vision Science Graduate Program, University of California, Berkeley, California, United States of America
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Roy Chowdhury U, Rinkoski TA, Bahler CK, Millar JC, Bertrand JA, Holman BH, Sherwood JM, Overby DR, Stoltz KL, Dosa PI, Fautsch MP. Effect of Cromakalim Prodrug 1 (CKLP1) on Aqueous Humor Dynamics and Feasibility of Combination Therapy With Existing Ocular Hypotensive Agents. Invest Ophthalmol Vis Sci 2017; 58:5731-5742. [PMID: 29114841 PMCID: PMC5678549 DOI: 10.1167/iovs.17-22538] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Purpose Cromakalim prodrug 1 (CKLP1) is a water-soluble ATP-sensitive potassium channel opener that has shown ocular hypotensive properties in ex vivo and in vivo experimental models. To determine its mechanism of action, we assessed the effect of CKLP1 on aqueous humor dynamics and in combination therapy with existing ocular hypotensive agents. Methods Outflow facility was assessed in C57BL/6 mice by ex vivo eye perfusions and by in vivo constant flow infusion following CKLP1 treatment. Human anterior segments with no trabecular meshwork were evaluated for effect on pressure following CKLP1 treatment. CKLP1 alone and in combination with latanoprost, timolol, and Rho kinase inhibitor Y27632 were evaluated for effect on intraocular pressure in C57BL/6 mice and Dutch-belted pigmented rabbits. Results CKLP1 lowered episcleral venous pressure (control: 8.9 ± 0.1 mm Hg versus treated: 6.2 ± 0.1 mm Hg, P < 0.0001) but had no detectable effect on outflow facility, aqueous humor flow rate, or uveoscleral outflow. Treatment with CKLP1 in human anterior segments without the trabecular meshwork resulted in a 50% ± 9% decrease in pressure, suggesting an effect on the distal portion of the conventional outflow pathway. CKLP1 worked additively with latanoprost, timolol, and Y27632 to lower IOP, presumably owing to combined effects on different aspects of aqueous humor dynamics. Conclusions CKLP1 lowered intraocular pressure by reducing episcleral venous pressure and lowering distal outflow resistance in the conventional outflow pathway. Owing to this unique mechanism of action, CKLP1 works in an additive manner to lower intraocular pressure with latanoprost, timolol, and Rho kinase inhibitor Y27632.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - Tommy A Rinkoski
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - Cindy K Bahler
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - J Cameron Millar
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Jacques A Bertrand
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Bradley H Holman
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - Joseph M Sherwood
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Kristen L Stoltz
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, United States
| | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, United States
| | - Michael P Fautsch
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
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Manicam C, Ginter N, Li H, Xia N, Goloborodko E, Zadeh JK, Musayeva A, Pfeiffer N, Gericke A. Compensatory Vasodilator Mechanisms in the Ophthalmic Artery of Endothelial Nitric Oxide Synthase Gene Knockout Mice. Sci Rep 2017; 7:7111. [PMID: 28769073 PMCID: PMC5541003 DOI: 10.1038/s41598-017-07768-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 06/29/2017] [Indexed: 01/02/2023] Open
Abstract
Nitric oxide (NO) generated by endothelial nitric oxide synthase (eNOS) plays an important role in the maintenance of ocular vascular homeostasis. Therefore, perturbations in vascular NO synthesis have been implicated in the pathogenesis of several ocular diseases. We recently reported that eNOS contributes significantly to vasodilation of the mouse ophthalmic artery. Interestingly, dilatory responses were also retained in eNOS gene-deficient mice (eNOS-/-), indicating inherent endothelial adaptive mechanism(s) that act as back-up systems in chronic absence of eNOS to preserve vasorelaxation. Thus, this study endeavoured to identify the compensatory mechanism(s) in the ophthalmic artery of eNOS-/- mice employing isolated arterial segments and pharmacological inhibitors in vitro. Endothelium removal virtually abolished acetylcholine (ACh)-induced vasodilation, suggesting an obligatory involvement of the endothelium in cholinergic control of vascular tone. However, non-NOS and non-cyclooxygenase components compensate for eNOS deficiency via endothelium-derived hyperpolarizing factors (EDHFs). Notably, arachidonic acid-derived metabolites of the 12-lipoxygenase pathway were key mediators in activating the inwardly rectifying potassium channels to compensate for chronic lack of eNOS. Conclusively, endothelium-dependent cholinergic responses of the ophthalmic artery in the eNOS-/- mice are largely preserved and, this vascular bed has the ability to compensate for the loss of normal vasodilator responses solely via EDHFs.
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Affiliation(s)
- Caroline Manicam
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany.
| | - Natalja Ginter
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Huige Li
- Institute of Pharmacology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Ning Xia
- Institute of Pharmacology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Evgeny Goloborodko
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Jenia Kouchek Zadeh
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Aytan Musayeva
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Norbert Pfeiffer
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Adrian Gericke
- Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany
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Morrison JC, Cepurna WO, Tehrani S, Choe TE, Jayaram H, Lozano DC, Fortune B, Johnson EC. A Period of Controlled Elevation of IOP (CEI) Produces the Specific Gene Expression Responses and Focal Injury Pattern of Experimental Rat Glaucoma. Invest Ophthalmol Vis Sci 2017; 57:6700-6711. [PMID: 27942722 PMCID: PMC5156512 DOI: 10.1167/iovs.16-20573] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We determine if several hours of controlled elevation of IOP (CEI) will produce the optic nerve head (ONH) gene expression changes and optic nerve (ON) damage pattern associated with early experimental glaucoma in rats. Methods The anterior chambers of anesthetized rats were cannulated and connected to a reservoir to elevate IOP. Physiologic parameters were monitored. Following CEI at various recovery times, ON cross-sections were graded for axonal injury. Anterior ONHs were collected at 0 hours to 10 days following CEI and RNA extracted for quantitative PCR measurement of selected messages. The functional impact of CEI was assessed by electroretinography (ERG). Results During CEI, mean arterial pressure (99 ± 6 mm Hg) and other physiologic parameters remained stable. An 8-hour CEI at 60 mm Hg produced significant focal axonal degeneration 10 days after exposure, with superior lesions in 83% of ON. Message analysis in CEI ONH demonstrated expression responses previously identified in minimally injured ONH following chronic IOP elevation, as well as their sequential patterns. Anesthesia with cannulation at 20 mm Hg did not alter these message levels. Electroretinographic A- and B-waves, following a significant reduction at 2 days after CEI, were fully recovered at 2 weeks, while peak scotopic threshold response (pSTR) remained mildly but significantly depressed. Conclusions A single CEI reproduces ONH message changes and patterns of ON injury previously observed with chronic IOP elevation. Controlled elevation of IOP can allow detailed determination of ONH cellular and functional responses to an injurious IOP insult and provide a platform for developing future therapeutic interventions.
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Affiliation(s)
- John C Morrison
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - William O Cepurna
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Shandiz Tehrani
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Tiffany E Choe
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Hari Jayaram
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States 2Glaucoma Service, NIHR Moorfields Biomedical Research Centre, London, United Kingdom
| | - Diana C Lozano
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Brad Fortune
- Devers Eye Institute, Portland, Oregon, United States
| | - Elaine C Johnson
- The Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
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Zhao D, Nguyen CTO, Wong VHY, Lim JKH, He Z, Jobling AI, Fletcher EL, Chinnery HR, Vingrys AJ, Bui BV. Characterization of the Circumlimbal Suture Model of Chronic IOP Elevation in Mice and Assessment of Changes in Gene Expression of Stretch Sensitive Channels. Front Neurosci 2017; 11:41. [PMID: 28239332 PMCID: PMC5301305 DOI: 10.3389/fnins.2017.00041] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/19/2017] [Indexed: 12/30/2022] Open
Abstract
To consider whether a circumlimbal suture can be used to chronically elevate intraocular pressure (IOP) in mice and to assess its effect on retinal structure, function and gene expression of stretch sensitive channels. Anesthetized adult C57BL6/J mice had a circumlimbal suture (10/0) applied around the equator of one eye. In treated eyes (n = 23) the suture was left in place for 12 weeks whilst in sham control eyes the suture was removed at day two (n = 17). Contralateral eyes served as untreated controls. IOP was measured after surgery and once a week thereafter. After 12 weeks, electroretinography (ERG) was performed to assess photoreceptor, bipolar cell and retinal ganglion cell (RGC) function. Retinal structure was evaluated using optical coherence tomography. Retinae were processed for counts of ganglion cell density or for quantitative RT-PCR to quantify purinergic (P2x7, Adora3, Entpd1) or stretch sensitive channel (Panx1, Trpv4) gene expression. Immediately after suture application, IOP spiked to 33 ± 3 mmHg. After 1 day, IOP had recovered to 27 ± 3 mmHg. Between weeks 2 and 12, IOP remained elevated above baseline (control 14 ± 1 mmHg, ocular hypertensive 19 ± 1 mmHg). Suture removal at day 2 (Sham) restored IOP to baseline levels, where it remained through to week 12. ERG analysis showed that 12 weeks of IOP elevation reduced photoreceptor (−15 ± 4%), bipolar cell (−15 ± 4%) and ganglion cell responses (−19 ± 6%) compared to sham controls and respective contralateral eyes (untreated). The retinal nerve fiber layer was thinned in the presence of normal total retinal thickness. Ganglion cell density was reduced across all quadrants (superior −12 ± 5%; temporal, −7% ± 2%; inferior −9 ± 4%; nasal −8 ± 5%). Quantitative RT-PCR revealed a significant increase in Entpd1 gene expression (+11 ± 4%), whilst other genes were not significantly altered (P2x7, Adora3, Trpv4, Panx1). Our results show that circumlimbal ligation produces mild chronic ocular hypertension and retinal dysfunction in mice. Consistent with a sustained change to purinergic signaling we found an up-regulation of Entpd1.
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Affiliation(s)
- Da Zhao
- Department of Optometry and Vision Sciences, University of Melbourne Parkville, VIC, Australia
| | - Christine T O Nguyen
- Department of Optometry and Vision Sciences, University of Melbourne Parkville, VIC, Australia
| | - Vickie H Y Wong
- Department of Optometry and Vision Sciences, University of Melbourne Parkville, VIC, Australia
| | - Jeremiah K H Lim
- Department of Optometry and Vision Sciences, University of Melbourne Parkville, VIC, Australia
| | - Zheng He
- Department of Optometry and Vision Sciences, University of Melbourne Parkville, VIC, Australia
| | - Andrew I Jobling
- Department of Anatomy and Neuroscience, University of Melbourne Parkville, VIC, Australia
| | - Erica L Fletcher
- Department of Anatomy and Neuroscience, University of Melbourne Parkville, VIC, Australia
| | - Holly R Chinnery
- Department of Optometry and Vision Sciences, University of Melbourne Parkville, VIC, Australia
| | - Algis J Vingrys
- Department of Optometry and Vision Sciences, University of Melbourne Parkville, VIC, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne Parkville, VIC, Australia
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Agarwal R, Agarwal P. Rodent models of glaucoma and their applicability for drug discovery. Expert Opin Drug Discov 2017; 12:261-270. [DOI: 10.1080/17460441.2017.1281244] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Renu Agarwal
- Center for Neuroscience Research, Faculty of Medicine, Universiti Teknologi MARA, Sungai Buloh Campus, Selangor, Malaysia
| | - Puneet Agarwal
- Faculty of Medicine, International Medical University, IMU Clinical Campus, Seremban, Malaysia
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Chen L, Zhao Y, Zhang H. Comparative Anatomy of the Trabecular Meshwork, the Optic Nerve Head and the Inner Retina in Rodent and Primate Models Used for Glaucoma Research. Vision (Basel) 2016; 1:vision1010004. [PMID: 31740629 PMCID: PMC6848998 DOI: 10.3390/vision1010004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 06/26/2016] [Accepted: 07/08/2016] [Indexed: 12/13/2022] Open
Abstract
Glaucoma is a heterogeneous group of ocular disorders with a multi-faceted etiology. Although numerous studies on glaucoma using different animal models have been published, it is unwise to simply generalize the results of one model to all glaucomatous situations because of the differences in the anatomy and morphology of animal eyes in comparison with humans’. In this review, we highlight the differences in the trabecular meshwork (TM) tissue, lamina cribrosa (LC) region, optic nerve head (ONH) and the inner layer of the retina in mice, rats and monkeys. In comparison with humans, non-human primates show TM, retina and ONH that are anatomically almost identical. The rat model shows many similarities in the aqueous outflow pathway compared to humans. The mouse ONH lacks collagenous LC, and this finding is observed across different mouse strains. The tissue structure of the ONH in rodents is similar to that in humans, although the blood supply shows differences. The number of cells in the ganglion layer depends on the rodent strain. Despite some differences from humans, rodents are a good choice for studying different types of glaucoma, and the modeling method should be selected based on the experimental needs and the hypothesis being tested.
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Affiliation(s)
| | | | - Hong Zhang
- Correspondence: ; Tel.: +86-139-7167-9079; Fax: +86-027-8366-3688
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The elevation of intraocular pressure is associated with apoptosis and increased immunoreactivity for nitric oxide synthase in rat retina whereas the effectiveness of retina derived relaxing factor is unaffected. Exp Eye Res 2016; 145:401-411. [DOI: 10.1016/j.exer.2016.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 02/05/2016] [Accepted: 03/02/2016] [Indexed: 01/18/2023]
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Caspase-7: a critical mediator of optic nerve injury-induced retinal ganglion cell death. Mol Neurodegener 2015; 10:40. [PMID: 26306916 PMCID: PMC4550044 DOI: 10.1186/s13024-015-0039-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 08/19/2015] [Indexed: 12/18/2022] Open
Abstract
Background Axonal injury of the optic nerve (ON) is involved in various ocular diseases, such as glaucoma and traumatic optic neuropathy, which leads to apoptotic death of retinal ganglion cells (RGCs) and loss of vision. Caspases have been implicated in RGC pathogenesis. However, the role of caspase-7, a functionally unique caspase, in ON injury and RGC apoptosis has not been reported previously. The purpose of this study is to evaluate the role of caspase-7 in ON injury-induced RGC apoptosis. Results C57BL/6 (wildtype, WT) and caspase-7 knockout (Casp7−/−) mice were used. We show that ON crush activated caspase-7 and calpain-1, an upstream activator of caspase-7, in mouse RGCs, as well as hydrolysis of kinectin and co-chaperone P23, specific substrates of caspase-7. ON crush caused a progressive loss of RGCs to 28 days after injury. Knockout of caspase-7 partially and significantly protected against the ON injury-induced RGC loss; RGC density at 28 days post ON crush in Casp7−/− mice was approximately twice of that in WT ON injured retinas. Consistent with changes in RGC counts, spectral-domain optical coherence tomography analysis revealed that ON crush significantly reduced the in vivo thickness of the ganglion cell complex layer (including ganglion cell layer, nerve fiber layer, and inner plexiform layer) in the retina. The ON crush-induced thinning of retinal layer was significantly ameliorated in Casp7−/− mice when compared to WT mice. Moreover, electroretinography analysis demonstrated a decline in the positive component of scotopic threshold response amplitude in ON crushed eyes of the WT mice, whereas this RGC functional response was significantly higher in Casp7−/− mice at 28 days post injury. Conclusion Altogether, our findings indicate that caspase-7 plays a critical role in ON injury-induced RGC death, and inhibition of caspase-7 activity may be a novel therapeutic strategy for glaucoma and other neurodegenerative diseases of the retina. Electronic supplementary material The online version of this article (doi:10.1186/s13024-015-0039-2) contains supplementary material, which is available to authorized users.
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Zhi Z, Cepurna W, Johnson E, Jayaram H, Morrison J, Wang RK. Evaluation of the effect of elevated intraocular pressure and reduced ocular perfusion pressure on retinal capillary bed filling and total retinal blood flow in rats by OMAG/OCT. Microvasc Res 2015; 101:86-95. [PMID: 26186381 DOI: 10.1016/j.mvr.2015.07.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 07/04/2015] [Accepted: 07/04/2015] [Indexed: 01/01/2023]
Abstract
PURPOSE To determine if retinal capillary filling is preserved in the face of acutely elevated intraocular pressure (IOP) in anesthetized rats, despite a reduction in total retinal blood flow (RBF), using optical microangiography/optical coherence tomography (OMAG/OCT). METHODS OMAG provided the capability of depth-resolved imaging of the retinal microvasculature down to the capillary level. Doppler OCT was applied to measure the total RBF using an enface integration approach. The microvascular pattern, capillary density, and total RBF were monitored in vivo as the IOP was increased from 10 to 100mmHg in 10mmHg intervals and returned back to 10mmHg. RESULTS In animals with mean arterial pressure (MAP) of 102±4mmHg (n=10), when IOP was increased from 0 to 100mmHg, the capillary density remained at or above 80% of baseline for the IOP up to 60mmHg [or ocular perfusion pressure (OPP) at 40mmHg]. This was then decreased, achieving 60% of baseline at IOP 70mmHg and OPP of 30mmHg. Total RBF was unaffected by moderate increases in IOP up to 30mmHg, beyond which total RBF decreased linearly, reaching 50% of baseline at IOP 60mmHg and OPP 40mmHg. Both capillary density and total RBF were totally extinguished at 100mmHg, but fully recovered when IOP returned to baseline. By comparison, a separate group of animals with lower MAP (mean=75±6mmHg, n=7) demonstrated comparable decreases in both capillary filling and total RBF at IOPs that were 20mmHg lower than in the initial group. Both were totally extinguished at 80mmHg, but fully recovered when IOP returned to baseline. Relationships of both parameters to OPP were unchanged. CONCLUSION Retinal capillary filling and total RBF responses to IOP elevation can be monitored non-invasively by OMAG/OCT and both are influenced by OPP. Retinal capillary filling was relatively preserved down to a perfusion pressure of 40mmHg, despite a linear reduction in total RBF.
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Affiliation(s)
- Zhongwei Zhi
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - William Cepurna
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Elaine Johnson
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Hari Jayaram
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - John Morrison
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA.
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Fortune B. In vivo imaging methods to assess glaucomatous optic neuropathy. Exp Eye Res 2015; 141:139-53. [PMID: 26048475 DOI: 10.1016/j.exer.2015.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 05/13/2015] [Accepted: 06/01/2015] [Indexed: 10/23/2022]
Abstract
The goal of this review is to summarize the most common imaging methods currently applied for in vivo assessment of ocular structure in animal models of experimental glaucoma with an emphasis on translational relevance to clinical studies of the human disease. The most common techniques in current use include optical coherence tomography and scanning laser ophthalmoscopy. In reviewing the application of these and other imaging modalities to study glaucomatous optic neuropathy, this article is organized into three major sections: 1) imaging the optic nerve head, 2) imaging the retinal nerve fiber layer and 3) imaging retinal ganglion cell soma and dendrites. The article concludes with a brief section on possible future directions.
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Affiliation(s)
- Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, 1225 NE Second Avenue, Portland, OR 97232, USA.
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Rat optic nerve head anatomy within 3D histomorphometric reconstructions of normal control eyes. Exp Eye Res 2015; 139:1-12. [PMID: 26021973 DOI: 10.1016/j.exer.2015.05.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 04/24/2015] [Accepted: 05/19/2015] [Indexed: 12/11/2022]
Abstract
The purpose of this study is to three-dimensionally (3D) characterize the principal macroscopic and microscopic relationships within the rat optic nerve head (ONH) and quantify them in normal control eyes. Perfusion-fixed, trephinated ONH from 8 normal control eyes of 8 Brown Norway Rats were 3D histomorphometrically reconstructed, visualized, delineated and parameterized. The rat ONH consists of 2 scleral openings, (a superior neurovascular and inferior arterial) separated by a thin connective tissue strip we have termed the "scleral sling". Within the superior opening, the nerve abuts a prominent extension of Bruch's Membrane (BM) superiorly and is surrounded by a vascular plexus, as it passes through the sclera, that is a continuous from the choroid into and through the dural sheath and contains the central retinal vein (CRV), (inferiorly). The inferior scleral opening contains the central retinal artery and three long posterior ciliary arteries which obliquely pass through the sclera to obtain the choroid. Bruch's Membrane Opening (BMO) is irregular and vertically elongated, enclosing the nerve (superiorly) and CRV and CRA (inferiorly). Overall mean BMO Depth, BMO Area, Choroidal Thickness and peripapillary Scleral Thickness were 29 μm, 56.5 × 10(3) μm(2), 57 μm and 104 μm respectively. Mean anterior scleral canal opening (ASCO) and posterior scleral canal opening (PSCO) radii were 201 ± 15 μm and 204 ± 16 μm, respectively. Mean optic nerve area at the ASCO and PSCO were 46.3 × 10(3)±4.4 × 10(3) μm(2) and 44.1 × 10(3)±4.5 × 10(3) μm(2) respectively. In conclusion, the 3D complexity of the rat ONH and the extent to which it differs from the primate have been under-appreciated within previous 2D studies. Properly understood, these anatomic differences may provide new insights into the relative susceptibilities of the rat and primate ONH to elevated intraocular pressure.
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Trost A, Motloch K, Bruckner D, Schroedl F, Bogner B, Kaser-Eichberger A, Runge C, Strohmaier C, Klein B, Aigner L, Reitsamer HA. Time-dependent retinal ganglion cell loss, microglial activation and blood-retina-barrier tightness in an acute model of ocular hypertension. Exp Eye Res 2015; 136:59-71. [PMID: 26001526 DOI: 10.1016/j.exer.2015.05.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 05/18/2015] [Accepted: 05/19/2015] [Indexed: 02/04/2023]
Abstract
Glaucoma is a group of neurodegenerative diseases characterized by the progressive loss of retinal ganglion cells (RGCs) and their axons, and is the second leading cause of blindness worldwide. Elevated intraocular pressure is a well known risk factor for the development of glaucomatous optic neuropathy and pharmacological or surgical lowering of intraocular pressure represents a standard procedure in glaucoma treatment. However, the treatment options are limited and although lowering of intraocular pressure impedes disease progression, glaucoma cannot be cured by the currently available therapy concepts. In an acute short-term ocular hypertension model in rat, we characterize RGC loss, but also microglial cell activation and vascular alterations of the retina at certain time points. The combination of these three parameters might facilitate a better evaluation of the disease progression, and could further serve as a new model to test novel treatment strategies at certain time points. Acute ocular hypertension (OHT) was induced by the injection of magnetic microbeads into the rat anterior chamber angle (n = 22) with magnetic position control, leading to constant elevation of IOP. At certain time points post injection (4d, 7d, 10d, 14d and 21d), RGC loss, microglial activation, and microvascular pericyte (PC) coverage was analyzed using immunohistochemistry with corresponding specific markers (Brn3a, Iba1, NG2). Additionally, the tightness of the retinal vasculature was determined via injections of Texas Red labeled dextran (10 kDa) and subsequently analyzed for vascular leakage. For documentation, confocal laser-scanning microscopy was used, followed by cell counts, capillary length measurements and morphological and statistical analysis. The injection of magnetic microbeads led to a progressive loss of RGCs at the five time points investigated (20.07%, 29.52%, 41.80%, 61.40% and 76.57%). Microglial cells increased in number and displayed an activated morphology, as revealed by Iba1-positive cell number (150.23%, 175%, 429.25%,486.72% and 544.78%) and particle size analysis (205.49%, 203.37%, 412.84%, 333.37% and 299.77%) compared to contralateral control eyes. Pericyte coverage (NG2-positive PC/mm) displayed a significant reduction after 7d of OHT in central, and after 7d and 10d in peripheral retina. Despite these alterations, the tightness of the retinal vasculature remained unaltered at 14 and 21 days after OHT induction. While vascular tightness was unchanged in the course of OHT, a progressive loss of RGCs and activation of microglial cells was detected. Since a significant loss in RGCs was observed already at day 4 of experimental glaucoma, and since activated microglia peaked at day 10, we determined a time frame of 7-14 days after MB injection as potential optimum to study glaucoma mechanisms in this model.
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Affiliation(s)
- A Trost
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria; Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria
| | - K Motloch
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria
| | - D Bruckner
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria
| | - F Schroedl
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria; Anatomy, Paracelsus Medical University, Salzburg, Austria
| | - B Bogner
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria
| | - A Kaser-Eichberger
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria
| | - C Runge
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria
| | - C Strohmaier
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria
| | - B Klein
- Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University Salzburg, Austria
| | - L Aigner
- Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University Salzburg, Austria
| | - H A Reitsamer
- University Clinic of Ophthalmology and Optometry, Research Program for Experimental Ophthalmology and Glaucoma Research, Paracelsus Medical University/SALK, 5020 Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University Salzburg, Austria.
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Karlstetter M, Scholz R, Rutar M, Wong WT, Provis JM, Langmann T. Retinal microglia: just bystander or target for therapy? Prog Retin Eye Res 2014; 45:30-57. [PMID: 25476242 DOI: 10.1016/j.preteyeres.2014.11.004] [Citation(s) in RCA: 374] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/20/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
Abstract
Resident microglial cells can be regarded as the immunological watchdogs of the brain and the retina. They are active sensors of their neuronal microenvironment and rapidly respond to various insults with a morphological and functional transformation into reactive phagocytes. There is strong evidence from animal models and in situ analyses of human tissue that microglial reactivity is a common hallmark of various retinal degenerative and inflammatory diseases. These include rare hereditary retinopathies such as retinitis pigmentosa and X-linked juvenile retinoschisis but also comprise more common multifactorial retinal diseases such as age-related macular degeneration, diabetic retinopathy, glaucoma, and uveitis as well as neurological disorders with ocular manifestation. In this review, we describe how microglial function is kept in balance under normal conditions by cross-talk with other retinal cells and summarize how microglia respond to different forms of retinal injury. In addition, we present the concept that microglia play a key role in local regulation of complement in the retina and specify aspects of microglial aging relevant for chronic inflammatory processes in the retina. We conclude that this resident immune cell of the retina cannot be simply regarded as bystander of disease but may instead be a potential therapeutic target to be modulated in the treatment of degenerative and inflammatory diseases of the retina.
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Affiliation(s)
- Marcus Karlstetter
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Rebecca Scholz
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Matt Rutar
- The John Curtin School of Medical Research, The Australian National University (ANU), Canberra, Australian Capital Territory, Australia
| | - Wai T Wong
- Unit on Neuron-Glia Interactions in Retinal Disease, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jan M Provis
- The John Curtin School of Medical Research, The Australian National University (ANU), Canberra, Australian Capital Territory, Australia
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany.
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Nashine S, Liu Y, Kim BJ, Clark AF, Pang IH. Role of C/EBP homologous protein in retinal ganglion cell death after ischemia/reperfusion injury. Invest Ophthalmol Vis Sci 2014; 56:221-31. [PMID: 25414185 DOI: 10.1167/iovs.14-15447] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
PURPOSE To investigate the role of C/EBP homologous protein (CHOP), a proapoptotic protein, and the unfolded protein response (UPR) marker that is involved in endoplasmic reticulum (ER) stress-mediated apoptosis in mouse retinal ganglion cell (RGC) death following ischemia/reperfusion (I/R) injury. METHODS Retinal I/R injury was induced in adult C57BL/6J wild-type (WT) and CHOP knockout (Chop(-/-)) mice by raising IOP to 120 mm Hg for 60 minutes. Expression of CHOP and other UPR markers was studied by Western blot and immunohistochemistry. Retinal ganglion cell counts were performed in retinal flat mounts stained with an RGC marker. Retinal ganglion cell function was evaluated by scotopic threshold response (STR) electroretinography. RESULTS In WT mice, retinal CHOP was upregulated by 30% in I/R-injured eyes compared to uninjured eyes 3 days after injury (P < 0.05). Immunohistochemistry confirmed CHOP upregulation specifically in RGCs. CHOP knockout did not affect baseline RGC density or STR amplitude. Ischemia/reperfusion injury decreased RGC densities and STR amplitudes in both WT and Chop(-/-) mice. However, survival of RGCs in I/R-injured Chop(-/-) mouse was 48% higher (P < 0.05) than that in I/R-injured WT mouse 3 days after I/R injury. Similarly, RGC density was significantly higher in Chop(-/-) eyes at 7, 14, and 28 days after I/R injury. Scotopic threshold response amplitudes of Chop(-/-) mice were significantly higher at 3 and 7 days after I/R than those of WT mice. CONCLUSIONS Absence of CHOP partially protects against RGC loss and reduction in retinal function after I/R injury, indicating that CHOP and, thus, ER stress play an important role in RGC apoptosis in retinal I/R injury.
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Affiliation(s)
- Sonali Nashine
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Yang Liu
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Byung-Jin Kim
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Iok-Hou Pang
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States Department of Pharmaceutical Sciences, University of North Texas Health Science Center, Fort Worth, Texas, United States
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Choe TE, Abbott CJ, Piper C, Wang L, Fortune B. Comparison of longitudinal in vivo measurements of retinal nerve fiber layer thickness and retinal ganglion cell density after optic nerve transection in rat. PLoS One 2014; 9:e113011. [PMID: 25393294 PMCID: PMC4231142 DOI: 10.1371/journal.pone.0113011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 10/23/2014] [Indexed: 11/23/2022] Open
Abstract
Purpose To determine the relationship between longitudinal in vivo measurements of retinal nerve fiber layer thickness (RNFLT) and retinal ganglion cell (RGC) density after unilateral optic nerve transection (ONT). Methods Nineteen adult Brown-Norway rats were studied; N = 10 ONT plus RGC label, N = 3 ONT plus vehicle only (sans label), N = 6 sham ONT plus RGC label. RNFLT was measured by spectral domain optical coherence tomography (SD-OCT) at baseline then weekly for 1 month. RGCs were labeled by retrograde transport of fluorescently conjugated cholera toxin B (CTB) from the superior colliculus 48 hours prior to ONT or sham surgery. RGC density measurements were obtained by confocal scanning laser ophthalmoscopy (CSLO) at baseline and weekly for 1 month. RGC density and reactivity of microglia (anti-Iba1) and astrocytes (anti-GFAP) were determined from post mortem fluorescence microscopy of whole-mount retinae. Results RNFLT decreased after ONT by 17% (p<0.05), 30% (p<0.0001) and 36% (p<0.0001) at weeks 2, 3 and 4. RGC density decreased after ONT by 18%, 69%, 85% and 92% at weeks 1, 2, 3 and 4 (p<0.0001 each). RGC density measured in vivo at week 4 and post mortem by microscopy were strongly correlated (R = 0.91, p<0.0001). In vivo measures of RNFLT and RGC density were strongly correlated (R = 0.81, p<0.0001). In ONT- CTB labeled fellow eyes, RNFLT increased by 18%, 52% and 36% at weeks 2, 3 and 4 (p<0.0001), but did not change in fellow ONT-eyes sans CTB. Microgliosis was evident in the RNFL of the ONT-CTB fellow eyes, exceeding that observed in other fellow eyes. Conclusions In vivo measurements of RNFLT and RGC density are strongly correlated and can be used to monitor longitudinal changes after optic nerve injury. The strong fellow eye effect observed in eyes contralateral to ONT, only in the presence of CTB label, consisted of a dramatic increase in RNFLT associated with retinal microgliosis.
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Affiliation(s)
- Tiffany E. Choe
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
| | - Carla J. Abbott
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
| | - Chelsea Piper
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
| | - Lin Wang
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon, United States of America
- * E-mail:
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A rat experimental model of glaucoma incorporating rapid-onset elevation of intraocular pressure. Sci Rep 2014; 4:5910. [PMID: 25081302 PMCID: PMC4118189 DOI: 10.1038/srep05910] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 07/01/2014] [Indexed: 11/08/2022] Open
Abstract
Glaucoma is a chronic disease that causes structural and functional damage to retinal ganglion cells (RGC). The currently employed therapeutic options are not sufficient to prevent vision loss in patients with glaucoma; therefore, there is a need to develop novel therapies, which requires the creation of functional, repeatable and easy-to-utilize animal models for use in pre-clinical studies. The currently available models ensure only low to moderate damage in optic nerves, with high variation in the outcomes and poor repeatability. We have developed an effective and reproducible rat glaucoma model based on a previous idea for a "Bead Model" in mice, which could be useful in future glaucoma research. Additionally, in an attempt to achieve rapid elevation of Intraocular Pressure (IOP), we included an initial "high-pressure injury" as part of this method, which serves as the equivalent of a severe glaucoma attack. These modifications made it possible to achieve longer lasting IOP elevation with chronic damage of retinal ganglion cells.
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Kwong JMK, Hoang C, Dukes RT, Yee RW, Gray BD, Pak KY, Caprioli J. Bis(zinc-dipicolylamine), Zn-DPA, a new marker for apoptosis. Invest Ophthalmol Vis Sci 2014; 55:4913-21. [PMID: 25034598 DOI: 10.1167/iovs.13-13346] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To characterize the labeling of apoptotic cells with a molecular probe of bis(zinc(II)-dipicolylamine) (Zn-DPA) conjugated with a fluorescent reporter in a rat model of retinal ganglion cell (RGC) degeneration induced by N-methyl-D-aspartate (NMDA). METHODS Adult Wistar rats were given unilateral intravitreal injections of 3 μL 40 mM neutralized NMDA and euthanized at 1, 2, 4, 24, and 48 hours. One hour before euthanasia, 3 μL Zn-DPA conjugated with fluorescein (Zn-DPA 480) was intravitreally injected. Prelabeling of RGC with retrograde fluorogold (FG), TUNEL, and immunohistochemistry with III β-tubulin and vimentin were performed. RESULTS Fluorescence labeling of Zn-DPA 480 was observed in the retinas from 1 hour up to 24 hours after NMDA injection, whereas the labeling was reduced at 48 hours postinjection. At both 4 and 24 hours postinjection, most Zn-DPA 480-positive cells in the RGC layer were labeled by FG and III β-tubulin. The number of TUNEL-positive cells increased from 4 to 24 hours. At 24 hours, 95.7% of Zn-DPA 480-positive cells were TUNEL positive, whereas 95.1% of TUNEL-positive cells were Zn-DPA 480 positive. The numbers of Zn-DPA 480-positive cells at 1 and 2 hours after NMDA injection were significantly higher than TUNEL. CONCLUSIONS Our findings demonstrate that intravitreal injection of fluorescent Zn-DPA 480 labels retinal neurons undergoing apoptosis and that recognition of exposed phosphatidylserine appears earlier than detection of DNA fragmentation, indicating the potential of Zn-DPA as an imaging probe for tracking degenerating retinal neurons.
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Affiliation(s)
- Jacky M K Kwong
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States
| | - Celia Hoang
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States
| | - Reshil T Dukes
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States
| | - Richard W Yee
- Cizik Eye Clinic, Hermann University Eye Associates, Houston, Texas, United States
| | - Brian D Gray
- Molecular Targeting Technologies, Inc., West Chester, Pennsylvania, United States
| | - Koon Y Pak
- Molecular Targeting Technologies, Inc., West Chester, Pennsylvania, United States
| | - Joseph Caprioli
- Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, California, United States
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