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Abstract
In many health-related fields, there is great interest in the identification of biomarkers that distinguish diseased from healthy individuals. In addition to identifying the diseased state, biomarkers have potential use in predicting disease risk, monitoring disease progression, evaluating treatment efficacy, and informing pathogenesis. This review details the genetic and biochemical markers associated with canine primary glaucoma. While there are numerous molecular markers (biochemical and genetic) associated with glaucoma in dogs, there is no ideal biomarker that allows early diagnosis and/or identification of disease progression. Genetic mutations associated with canine glaucoma include those affecting ADAMTS10, ADAMTS17, Myocilin, Nebulin, COL1A2, RAB22A, and SRBD1. With the exception of Myocilin, there is very limited crossover in genetic biomarkers identified between human and canine glaucomas. Mutations associated with canine glaucoma vary between and within canine breeds, and gene discoveries therefore have limited overall effects as a screening tool in the general canine population. Biochemical markers of glaucoma include indicators of inflammation, oxidative stress, serum autoantibodies, matrix metalloproteinases, tumor necrosis factor–α, and transforming growth factor–β. These markers include those that indicate an adaptive or protective response, as well as those that reflect the damage arising from oxidative stress.
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Affiliation(s)
- K. L. Graham
- Department of Ophthalmology and Eye Health, Sydney Medical School, University of Sydney, New South Wales, Australia
| | - C. McCowan
- Department of Pathology, Faculty of Veterinary Science, University of Melbourne, Parkville, Australia
- Department of Economic Development, Jobs, Transport and Resources, Victoria, Australia
| | - A. White
- Department of Ophthalmology and Eye Health, Sydney Medical School, University of Sydney, New South Wales, Australia
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Pizzirani S. Definition, Classification, and Pathophysiology of Canine Glaucoma. Vet Clin North Am Small Anim Pract 2016; 45:1127-57, v. [PMID: 26456751 DOI: 10.1016/j.cvsm.2015.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Glaucoma is a common ocular condition in humans and dogs leading to optic nerve degeneration and irreversible blindness. Primary glaucoma is a group of spontaneous heterogeneous diseases. Multiple factors are involved in its pathogenesis and these factors vary across human ethnic groups and canine breeds, so the clinical phenotypes are numerous and their classification can be challenging and remain superficial. Aging and oxidative stress are major triggers for the manifestation of disease. Multiple, intertwined inflammatory and biochemical cascades eventually alter cellular and extracellular physiology in the optic nerve and trabecular meshwork and lead to vision loss.
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Affiliation(s)
- Stefano Pizzirani
- Ophthalmology, Department of Clinical Science, Cummings School of Veterinary Medicine, Tufts University, 200 Westboro Road, North Grafton, MA 01536, USA.
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Komáromy AM, Petersen-Jones SM. Genetics of Canine Primary Glaucomas. Vet Clin North Am Small Anim Pract 2015; 45:1159-82, v. [PMID: 26277300 DOI: 10.1016/j.cvsm.2015.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Primary glaucomas are a leading cause of incurable vision loss in dogs. Based on their specific breed predilection, a genetic cause is suspected to be responsible, and affected dogs should be excluded from breeding. Despite the high prevalence of primary glaucomas in dogs, their genetics have been studied in only a small number of breeds. The identification of canine glaucoma disease genes, and the development of genetic tests, will help to avoid the breeding of affected dogs in the future and will allow for earlier diagnosis and potentially more effective therapy.
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Affiliation(s)
- András M Komáromy
- Department of Small Animal Clinical Sciences, Veterinary Medical Center, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, Room D-208, East Lansing, MI 48824, USA.
| | - Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, Veterinary Medical Center, College of Veterinary Medicine, Michigan State University, 736 Wilson Road, Room D-208, East Lansing, MI 48824, USA
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Chen T, Gionfriddo JR, Tai PY, Novakowski AN, Alyahya K, Madl JE. Oxidative stress increases in retinas of dogs in acute glaucoma but not in chronic glaucoma. Vet Ophthalmol 2014; 18:261-70. [PMID: 24814303 DOI: 10.1111/vop.12177] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To test the hypothesis that oxidative stress occurs early in the pathogenesis of glaucoma in dogs. ANIMALS Sections from eight control retinas and 25 retinas from dogs with primary glaucoma. METHODS For retinas embedded in paraffin, sections were immunohistochemically stained for malondialdehyde (MDA) and 3-nitrotyrosine (NT). For retinas embedded in plastic, serial 0.5-μm sections were immunogold-stained for total glutathione, taurine, and glutamate. RESULTS Increased immunostaining for MDA and NT, markers of oxidative stress, occurred in retinal ganglion cells (RGCs) and other neurons in acute glaucoma, but not in chronic glaucoma. In minimally damaged regions, immunostaining for the antioxidant glutathione was decreased in RGCs, neurons of the inner nuclear layer (INL), and Müller cell processes. The loss of glutathione immunostaining in RGCs occurred without a decrease in glutamate immunostaining. Neurons with nuclear damage in the INL had low levels of glutathione, taurine, and glutamate. In severely damaged regions, immunostaining for glutathione was increased in the remaining retinal tissue. CONCLUSIONS Immunohistochemical staining revealed an increase in markers of oxidative stress and loss of glutathione in neurons with minimal damage during acute glaucoma. Oxidative changes were no longer present in chronic glaucomatous retinas, suggesting transient oxidative stress occurs early in glaucoma. The loss of glutathione in minimally damaged regions occurred without a significant redistribution of glutamate, suggesting oxidative stress may occur before glutamate redistribution. Alteration in markers of oxidative stress occurs early in canine glaucoma, suggesting oxidative stress may contribute to subsequent glutamate redistribution and other damaging processes.
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Affiliation(s)
- Thomas Chen
- Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado
| | - Juliet R Gionfriddo
- Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado
| | - Pei-Yi Tai
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Anna N Novakowski
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Khaleel Alyahya
- College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - James E Madl
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
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Madl JE, Duncan CG, Stanhill JE, Tai PY, Spraker TR, Gulland FM. Oxidative stress and redistribution of glutamine synthetase in California sea lions (Zalophus californianus) with domoic acid toxicosis. J Comp Pathol 2013; 150:306-15. [PMID: 24060152 DOI: 10.1016/j.jcpa.2013.07.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 05/29/2013] [Accepted: 07/12/2013] [Indexed: 11/19/2022]
Abstract
The aim of this study was to test the hypothesis that oxidative stress and glutamine synthetase (GS) redistribution occur in domoic acid (DA) toxicosis in California sea lions (CSLs, Zalophus californianus). Sections of archived hippocampi from seven control and 13 CSLs diagnosed with DA toxicosis were labelled immunohistochemically for GS and for two markers of oxidative stress, malondialdehyde (MDA) and 3-nitrotyrosine (NT). The distribution and intensity of labelling were compared with the pathological changes seen in haematoxylin and eosin-stained sections. Increased expression of MDA and NT occurred in neurons of the hippocampal formation of CSLs with lesions consistent with DA toxicosis. The degree of oxidative stress was not affected significantly by the chronicity or severity of hippocampal damage. In six out of seven CSLs with chronic effects of DA toxicosis, in addition to the normal glial distribution of GS, GS expression was very strong in some neurons of the subiculum. However, neuronal GS labelling was also seen in one control CSL, an effect that may have been due to previous exposure to DA. GS expression in neurons was associated with decreases in GS labelling in neighbouring glial cell processes. DA toxicosis therefore induces increased expression of markers of oxidative stress in neurons consistent with oxidative stress contributing to the initial DA insult and also the epilepsy that often develops in chronic DA toxicosis. GS redistribution occurred primarily in chronic DA toxicosis, perhaps leading to alterations of the glutamine-glutamate-GABA (gamma-aminobutyric acid) cycle and contributing to the excitotoxicity and seizures often seen in DA toxicosis.
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Affiliation(s)
- J E Madl
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, USA.
| | - C G Duncan
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - J E Stanhill
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - P-Y Tai
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - T R Spraker
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - F M Gulland
- The Marine Mammal Center, 2000 Bunker Road, Sausalito, CA 94965, USA
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Dees DD, Fritz KJ, MacLaren NE, Esson DW, Sheehan Gaerig AM, Atkins RM, Knollinger AM. Efficacy of prophylactic antiglaucoma and anti-inflammatory medications in canine primary angle-closure glaucoma: a multicenter retrospective study (2004-2012). Vet Ophthalmol 2013; 17:195-200. [DOI: 10.1111/vop.12069] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D. Dustin Dees
- Eye Care for Animals; 1021 E. 3300 S. Salt Lake City UT 84106 USA
| | - Kevin J. Fritz
- Eye Care for Animals; 3025 Edinger Avenue Tustin CA 92780 USA
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Strom AR, Hässig M, Iburg TM, Spiess BM. Epidemiology of canine glaucoma presented to University of Zurich from 1995 to 2009. Part 1: Congenital and primary glaucoma (4 and 123 cases). Vet Ophthalmol 2011; 14:121-6. [PMID: 21366828 DOI: 10.1111/j.1463-5224.2010.00855.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To investigate the epidemiology of canine congenital and primary glaucoma in the cases presented to the University of Zurich, Vetsuisse Faculty (UZH) from 1995 to 2009. METHODS Information was obtained from the computer database of patients examined by members of the UZH Ophthalmology Service, between January 1995 and August 2009. Congenital and primary glaucoma was diagnosed based on the age of onset, the lack of evidence of any antecedent eye conditions, and/or the presence and severity of iridocorneal angle defects. The data was evaluated for breed, gender and age at presentation. RESULTS A total of 5984 dogs presented to the UZH Ophthalmology service between 1995 and 2009. Four dogs of different breed were diagnosed with congenital glaucoma and 123 dogs were diagnosed with primary glaucoma. For the primary glaucomas the overall male to female ratio (M:F) was 1:1.41 and the age of onset ranged from 0.12 to 18.3 years with a mean of 7.3 ± 3.6 years. Data suggested a predisposition for primary glaucoma in the Siberian Husky, Magyar Vizsla and Newfoundland from 2004 to 2009. CONCLUSION The report presents the epidemiology of canine congenital and primary glaucomas presented to the UZH from 1995 to 2009. A previous suspicion of predisposition for primary glaucoma in the Newfoundland dog (n = 6) and the Magyar Vizsla breed (n = 8) was confirmed.
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Affiliation(s)
- Ann Refstrup Strom
- Department of Small Animal Clinical Sciences,Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
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da Silva EG, Gionfriddo JR, Hudachek SF, Gustafson DL, Olea-Popelka FJ, Scofield VL, Powell CC, Hill AE. Evaluation of the ocular penetration of topical alpha-luminol (Galavit®/GVT®). Vet Ophthalmol 2011; 14:180-5. [PMID: 21521442 DOI: 10.1111/j.1463-5224.2010.00862.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE Oxidative stress plays a major role in the pathogenesis of many neurodegenerative diseases. It has also been implicated as part of the pathogenic mechanisms in the development of glaucoma. Alpha-luminol has shown profound anti-inflammatory and antioxidant effects in both experimental animal and human clinical studies. The purpose of this pilot study was to investigate for the first time the ocular penetration of topical alpha-luminol. METHODS Nine animals were divided into three treated groups (three animals each; one drop OU/n = 18), each group receiving a different concentration of the eyedrop (0.5%, 1.5%, 2.5%). Aqueous humor and peripheral blood samples were obtained from each rabbit at three different timepoints (20 min, 4 h and 12 h). Samples were analyzed by means of high performance liquid chromatography and mass spectrometry; median values were compared. RESULTS Alpha-luminol was found in the aqueous humor in all treated groups at all timepoints. At the 2nd and 3rd timepoints (4 h and 12 h), aqueous humor levels decreased significantly (P < 0.05) for two of the three dosages tested and it was not detectable in some eyes. The highest aqueous humor concentration of the drug was 272 ng/mL after 20 min (0.0217% of one drop, 2.5% group). Alpha-luminol was found in the vitreous in two animals, one in the 1.5% and another in the 2.5% group (16.4 and 21.5 ng/mL, respectively), at 12 h. CONCLUSIONS Topically administered alpha-luminol readily penetrates into the anterior chamber and can penetrate into the vitreous chamber. Further investigation is warranted to better understand the intraocular pharmacokinetics of alpha-luminol.
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Affiliation(s)
- Enry G da Silva
- Department of Clinical Sciences, Colorado State University, College of Veterinary Medicine, Fort Collins, CO, USA.
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Gionfriddo JR, Freeman KS, Groth A, Scofield VL, Alyahya K, Madl JE. alpha-Luminol prevents decreases in glutamate, glutathione, and glutamine synthetase in the retinas of glaucomatous DBA/2J mice. Vet Ophthalmol 2009; 12:325-32. [PMID: 19751494 DOI: 10.1111/j.1463-5224.2009.00722.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To test the hypothesis that in DBA/2J mice, oxidative stress decreases glutamine synthetase (GS) levels resulting in a loss of neuronal glutamate and that the antioxidant alpha-luminol (GVT) decreases this stress and glutamate loss in some types of glaucoma. ANIMALS DBA/2J mice were separated into two groups, of which one was not treated, and the other treated with GVT in the drinking water. At 7 months of age, retinas were examined from five untreated DBA/2J mice, seven GVT-treated mice, and five C57BL/6 mice (negative controls). METHODS Serial 0.5 microm plastic sections were immunogold stained for glutamate, GS, and total glutathione, followed by image analysis for staining patterns and density. RESULTS Focal decreases in glutamate immunostaining were common in the inner nuclear layer (INL) of DBA/2J retinas, but not in C57BL/6 or GVT-treated DBA/2J retinas. Decreases in glutathione and GS immunostaining were found in DBA/2J retinal regions where neuronal glutamate immunostaining was reduced. Retinas from GVT-treated DBA/2J had no significant decreases in INL levels of glutamate, glutathione, or GS. CONCLUSIONS Retinas of dogs with primary glaucoma are reported to have focal depletion of neuronal glutamate. In DBA/2J mice, similar changes occur prior to the development of clinical disease. In these focal glutamate-depleted regions, levels of glutathione and GS are also reduced, consistent with the hypothesis that oxidative stress contributes to retinal changes in glaucoma. The ability of GVT, an antioxidant, to inhibit retinal abnormalities in DBA/2J mice provides further support for this hypothesis.
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Affiliation(s)
- Juliet R Gionfriddo
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO, USA
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Tonar Z, Egger GF, Witter K, Wolfesberger B. Quantification of microvessels in canine lymph nodes. Microsc Res Tech 2008; 71:760-72. [PMID: 18615685 DOI: 10.1002/jemt.20619] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Quantification of microvessels in tumors is mostly based on counts of vessel profiles in tumor hot spots. Drawbacks of this method include low reproducibility and large interobserver variance, mainly as a result of individual differences in sampling of image fields for analysis. Our aim was to test an unbiased method for quantifying microvessels in healthy and tumorous lymph nodes of dogs. The endothelium of blood vessels was detected in paraffin sections by a combination of immunohistochemistry (von Willebrand factor) and lectin histochemistry (wheat germ agglutinin) in comparison with detection of basal laminae by laminin immunohistochemistry or silver impregnation. Systematic uniform random sampling of 50 image fields was performed during photo-documentation. An unbiased counting frame (area 113,600 microm(2)) was applied to each micrograph. The total area sampled from each node was 5.68 mm(2). Vessel profiles were counted according to stereological counting rules. Inter- and intraobserver variabilities were tested. The application of systematic uniform random sampling was compared with the counting of vessel profiles in hot spots. The unbiased estimate of the number of vessel profiles per unit area ranged from 100.5 +/- 44.0/mm(2) to 442.6 +/- 102.5/mm(2) in contrast to 264 +/- 72.2/mm(2) to 771.0 +/- 108.2/mm(2) in hot spots. The advantage of using systematic uniform random sampling is its reproducibility, with reasonable interobserver and low intraobserver variance. This method also allows for the possibility of using archival material, because staining quality is not limiting as it is for image analysis, and artifacts can easily be excluded. However, this method is comparatively time-consuming.
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Affiliation(s)
- Zbynĕk Tonar
- Department of Histology and Embryology, Faculty of Medicine in Pilsen, Charles University in Prague, Karlovarska 48, 301 66 Pilsen, Czech Republic.
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