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Gao Y, Zhang X, Wu D, Wu C, Ren C, Meng T, Ji X. Evaluation of peripapillary retinal nerve fiber layer thickness in intracranial atherosclerotic stenosis. BMC Ophthalmol 2023; 23:455. [PMID: 37957614 PMCID: PMC10641930 DOI: 10.1186/s12886-023-03196-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 11/01/2023] [Indexed: 11/15/2023] Open
Abstract
PURPOSE To evaluate the peripapillary retinal nerve fiber layer thickness (pRNFL) in patients with intracranial atherosclerotic stenosis (ICAS). METHODS A cross-sectional study was performed in a general hospital. The intracranial atherosclerotic stenosis was evaluated by digital subtraction angiography (DSA), computed tomography angiography (CTA) or magnetic resonance angiography (MRA). High-definition optical coherence tomography (HD-OCT) was used to evaluate the peripapillary retinal nerve fiber layer thickness. RESULTS A total of 102 patients, including 59(57.8%) patients with ICAS and 43(42.2%) patients without ICAS, were finally analysed in the study. The peripapillary retinal nerve fiber layer thickness (pRNFL) was reduced significantly in the average, the superior and the inferior quadrants of the ipsilateral eyes and in the superior quadrant of the contralateral eyes in patients with ICAS compared with patients without ICAS. After multivariate analysis, only the superior pRNFL thickness in the ipsilateral eyes was significantly associated with ICAS (OR,0.968; 95% CI,0.946-0.991; p = 0.006). The area under receiver operator curve was 0.679 (95% CI,0.576-0.782) for it to identify the presence of ICAS. The cut-off value of the superior pRNFL was 109.5 μm, and the sensitivity and specificity were 50.8% and 83.7%, respectively. CONCLUSION The superior pRNFL in the ipsilateral eye was significantly associated with ICAS in this study. Larger studies are needed to explore the relation between pRNFL and ICAS further.
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Affiliation(s)
- Yuan Gao
- Department of Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, 100191, Beijing, China
- Department of Ophthalmology, Xuanwu hospital, Capital Medical University, 100053, Beijing, China
| | - Xuxiang Zhang
- Department of Ophthalmology, Xuanwu hospital, Capital Medical University, 100053, Beijing, China
| | - Di Wu
- China-America Institute of Neuroscience, Xuanwu hospital, Capital Medical University, 100053, Beijing, China
| | - Chuanjie Wu
- Department of Neurology, Xuanwu hospital, Capital Medical University, 100053, Beijing, China
| | - Changhong Ren
- Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu hospital, Capital Medical University, 100053, Beijing, China
| | - Tingting Meng
- Department of Ophthalmology, Xuanwu hospital, Capital Medical University, 100053, Beijing, China
| | - Xunming Ji
- Department of Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, 100191, Beijing, China.
- Department of Neurology, Xuanwu hospital, Capital Medical University, 100053, Beijing, China.
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2
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Justić H, Barić A, Šimunić I, Radmilović M, Ister R, Škokić S, Dobrivojević Radmilović M. Redefining the Koizumi model of mouse cerebral ischemia: A comparative longitudinal study of cerebral and retinal ischemia in the Koizumi and Longa middle cerebral artery occlusion models. J Cereb Blood Flow Metab 2022; 42:2080-2094. [PMID: 35748043 PMCID: PMC9580169 DOI: 10.1177/0271678x221109873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cerebral and retinal ischemia share similar pathogenesis and epidemiology, each carrying both acute and prolonged risk of the other and often co-occurring. The most used preclinical stroke models, the Koizumi and Longa middle cerebral artery occlusion (MCAO) methods, have reported retinal damage with great variability, leaving the disruption of retinal blood supply via MCAO poorly investigated, even providing conflicting assumptions on the origin of the ophthalmic artery in rodents. The aim of our study was to use longitudinal in vivo magnetic resonance assessment of cerebral and retinal vascular perfusion after the ischemic injury to clarify whether and how the Koizumi and Longa methods induce retinal ischemia and how they differ in terms of cerebral and retinal lesion evolution. We provided anatomical evidence of the origin of the ophthalmic artery in mice from the pterygopalatine artery. Following the Koizumi surgery, retinal responses to ischemia overlapped with those in the brain, resulting in permanent damage. In contrast, the Longa method produced only extensive cerebral lesions, with greater tissue loss than in the Koizumi method. Additionally, our data suggests the Koizumi method should be redefined as a model of ischemia with chronic hypoperfusion rather than of ischemia and reperfusion.
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Affiliation(s)
- Helena Justić
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia.,Department of Histology and Embryology, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Anja Barić
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia.,Department of Histology and Embryology, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Iva Šimunić
- Department of Histology and Embryology, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Marin Radmilović
- Department of Ophthalmology, Sestre Milosrdnice University Hospital Center, Zagreb, Croatia *These authors contributed equally to this work
| | - Rok Ister
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia.,Department of Histology and Embryology, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Siniša Škokić
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Marina Dobrivojević Radmilović
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia.,Department of Histology and Embryology, University of Zagreb School of Medicine, Zagreb, Croatia
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3
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Tang LHC, Fung FKC, Lai AKW, Wong IYH, Shih KC, Lo ACY. Autophagic Upregulation Is Cytoprotective in Ischemia/Reperfusion-Injured Retina and Retinal Progenitor Cells. Int J Mol Sci 2021; 22:8446. [PMID: 34445152 PMCID: PMC8395130 DOI: 10.3390/ijms22168446] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 11/16/2022] Open
Abstract
The cytoprotective versus cytotoxic role of macroautophagy in ocular ischemia/reperfusion injuries remains controversial and its effects under hyperglycemia are unclear. We investigated the involvement of autophagy in in vitro and in vivo normoglycemic and hyperglycemic models of retinal ischemia/reperfusion injury. Retinal ischemia (2 h) and reperfusion (2 or 22 h) was induced in wild-type and type I diabetic Ins2Akita/+ mice using a middle cerebral artery occlusion model. R28 retinal precursor cells were subjected to CoCl2-induced hypoxia with or without autophagic inhibitor NH4Cl. Autophagic regulation during ischemia/reperfusion was assessed through immunohistochemical detection and Western blotting of microtubule-associated protein 1A/1B-light chain 3 (LC3) and lysosomal associated membrane protein 1 (LAMP1). Effect of autophagic inhibition on cell viability and morphology under hypoxic conditions was also evaluated. Upregulation of autophagic markers in the inner retinae was seen after two hours reperfusion, with tapering of the response following 22 h of reperfusion in vivo. LC3-II turnover assays confirmed an increase in autophagic flux in our hypoxic in vitro model. Pharmacological autophagic inhibition under hypoxic conditions decreased cell survival and induced structural changes not demonstrated with autophagic inhibition alone. Yet no statistically significant different autophagic responses in ischemia/reperfusion injuries were seen between the two glycemic states.
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Affiliation(s)
| | | | | | | | | | - Amy Cheuk Yin Lo
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong; (L.H.C.T.); (F.K.C.F.); (A.K.W.L.); (I.Y.H.W.); (K.C.S.)
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4
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Lee JY, Castelli V, Bonsack B, García-Sánchez J, Kingsbury C, Nguyen H, Tajiri N, Borlongan CV. Eyeballing stroke: Blood flow alterations in the eye and visual impairments following transient middle cerebral artery occlusion in adult rats. Cell Transplant 2021; 29:963689720905805. [PMID: 32098493 PMCID: PMC7444237 DOI: 10.1177/0963689720905805] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Middle cerebral artery occlusion in rodents remains a widely used model
of ischemic stroke. Recently, we reported the occurrence of retinal
ischemia in animals subjected to middle cerebral artery occlusion,
owing in part to the circulatory juxtaposition of the ophthalmic
artery to the middle cerebral artery. In this study, we examined the
eye hemodynamics and visual deficits in middle cerebral artery
occlusion-induced stroke rats. The brain and eye were evaluated by
laser Doppler at baseline (prior to middle cerebral artery occlusion),
during and after middle cerebral artery occlusion. Retinal
function-relevant behavioral and histological outcomes were performed
at 3 and 14 days post-middle cerebral artery occlusion. Laser Doppler
revealed a typical reduction of at least 80% in the ipsilateral
frontoparietal cortical area of the brain during middle cerebral
artery occlusion compared to baseline, which returned to near-baseline
levels during reperfusion. Retinal perfusion defects closely
paralleled the timing of cerebral blood flow alterations in the acute
stages of middle cerebral artery occlusion in adult rats,
characterized by a significant blood flow defect in the ipsilateral
eye with at least 90% reduction during middle cerebral artery
occlusion compared to baseline, which was restored to near-baseline
levels during reperfusion. Moreover, retinal ganglion cell density and
optic nerve depth were significantly decreased in the ipsilateral eye.
In addition, the stroke rats displayed eye closure. Behavioral
performance in a light stimulus-mediated avoidance test was
significantly impaired in middle cerebral artery occlusion rats
compared to control animals. In view of visual deficits in stroke
patients, closely monitoring of brain and retinal perfusion via laser
Doppler measurements and examination of visual impairments may
facilitate the diagnosis and the treatment of stroke, including
retinal ischemia.
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Affiliation(s)
- Jea-Young Lee
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Vanessa Castelli
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Brooke Bonsack
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Julián García-Sánchez
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Chase Kingsbury
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Hung Nguyen
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Naoki Tajiri
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
| | - Cesar V Borlongan
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida College of Medicine, USA
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5
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Chronic stepwise cerebral hypoperfusion differentially induces synaptic proteome changes in the frontal cortex, occipital cortex, and hippocampus in rats. Sci Rep 2020; 10:15999. [PMID: 32994510 PMCID: PMC7524772 DOI: 10.1038/s41598-020-72868-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 09/07/2020] [Indexed: 11/20/2022] Open
Abstract
During chronic cerebral hypoperfusion (CCH), the cerebral blood flow gradually decreases, leading to cognitive impairments and neurodegenerative disorders, such as vascular dementia. The reduced oxygenation, energy supply induced metabolic changes, and insufficient neuroplasticity could be reflected in the synaptic proteome. We performed stepwise bilateral common carotid occlusions on rats and studied the synaptic proteome changes of the hippocampus, occipital and frontal cortices. Samples were prepared and separated by 2-D DIGE and significantly altered protein spots were identified by HPLC–MS/MS. We revealed an outstanding amount of protein changes in the occipital cortex compared to the frontal cortex and the hippocampus with 94, 33, and 17 proteins, respectively. The high alterations in the occipital cortex are probably due to the hypoxia-induced retrograde degeneration of the primary visual cortex, which was demonstrated by electrophysiological experiments. Altered proteins have functions related to cytoskeletal organization and energy metabolism. As CCH could also be an important risk factor for Alzheimer’s disease (AD), we investigated whether our altered proteins overlap with AD protein databases. We revealed a significant amount of altered proteins associated with AD in the two neocortical areas, suggesting a prominent overlap with the AD pathomechanism.
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6
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Blair NP, Leahy S, Nathanael Matei, Shahidi M. Control of retinal blood flow levels by selected combinations of cervical arterial ligations in rat. Exp Eye Res 2020; 197:108088. [PMID: 32502531 DOI: 10.1016/j.exer.2020.108088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 10/24/2022]
Abstract
The effect of various combinations of cervical arterial ligations (Combinations) on retinal blood flow (RBF) levels is not known in rats. We hypothesized: 1) No artery exists between the Circle of Willis and the eye, 2) Selective Combinations enable varying RBF levels between normal and zero, 3) In certain Combinations, the capillary bed of the head participates in supplying the eye. Twenty-six Combinations were studied in one eye of 20 Long-Evans rats under general anesthesia. RBF was quantitatively evaluated with our published imaging methods based on direct measurements of venous diameter and blood velocity from the displacement of fluorescent microspheres over time. For each Combination, one or more RBF values (runs) were measured. Data were obtained from 59 runs (2.9 ± 2.7 runs/rat). Levels of RBF ranged from normal to zero. An artery between the Circle of Willis and the eye was excluded. With some Combinations, flow traversed the capillary bed. Combinations were consolidated into five Groups based on the blood flow paths remaining after the ligations. A mixed linear model accounting for multiple measurements in the same eye demonstrated an effect of Group on RBF (P < 0.0005). By major source of ocular blood supply, the trend of RBF levels was: ipsilateral carotid artery > contralateral carotid artery > ipsilateral distal internal carotid artery retrograde from Circle of Willis. The findings advanced knowledge of the sources of blood supply to the rat eye and demonstrated a method of selective cervical arterial ligations for varying RBF levels with potential to impact future retinal ischemia research.
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Affiliation(s)
- Norman P Blair
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, United States.
| | - Sophie Leahy
- Department of Ophthalmology, University of Southern California, United States.
| | - Nathanael Matei
- Department of Ophthalmology, University of Southern California, United States.
| | - Mahnaz Shahidi
- Department of Ophthalmology, University of Southern California, United States.
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7
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Kingsbury C, Heyck M, Bonsack B, Lee JY, Borlongan CV. Stroke gets in your eyes: stroke-induced retinal ischemia and the potential of stem cell therapy. Neural Regen Res 2019; 15:1014-1018. [PMID: 31823871 PMCID: PMC7034271 DOI: 10.4103/1673-5374.270293] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Stroke persists as a global health and economic crisis, yet only two interventions to reduce stroke-induced brain injury exist. In the clinic, many patients who experience an ischemic stroke often further suffer from retinal ischemia, which can inhibit their ability to make a functional recovery and may diminish their overall quality of life. Despite this, no treatments for retinal ischemia have been developed. In both cases, ischemia-induced mitochondrial dysfunction initiates a cell loss cascade and inhibits endogenous brain repair. Stem cells have the ability to transfer healthy and functional mitochondria not only ischemic neurons, but also to similarly endangered retinal cells, replacing their defective mitochondria and thereby reducing cell death. In this review, we encapsulate and assess the relationship between cerebral and retinal ischemia, recent preclinical advancements made using in vitro and in vivo retinal ischemia models, the role of mitochondrial dysfunction in retinal ischemia pathology, and the therapeutic potential of stem cell-mediated mitochondrial transfer. Furthermore, we discuss the pitfalls in classic rodent functional assessments and the potential advantages of laser Doppler as a metric of stroke progression. The studies evaluated in this review highlight stem cell-derived mitochondrial transfer as a novel therapeutic approach to both retinal ischemia and stroke. Furthermore, we posit the immense correlation between cerebral and retinal ischemia as an underserved area of study, warranting exploration with the aim of these treating injuries together.
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Affiliation(s)
- Chase Kingsbury
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa, FL, USA
| | - Matt Heyck
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa, FL, USA
| | - Brooke Bonsack
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa, FL, USA
| | - Jea-Young Lee
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa, FL, USA
| | - Cesar V Borlongan
- Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa, FL, USA
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8
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Blair NP, Tan MR, Felder AE, Shahidi M. Retinal Oxygen Delivery, Metabolism and Extraction Fraction and Retinal Thickness Immediately Following an Interval of Ophthalmic Vessel Occlusion in Rats. Sci Rep 2019; 9:8092. [PMID: 31147557 PMCID: PMC6542852 DOI: 10.1038/s41598-019-44250-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 05/09/2019] [Indexed: 11/30/2022] Open
Abstract
Limited knowledge is currently available about alterations of retinal blood flow (F), oxygen delivery (DO2), oxygen metabolism (MO2), oxygen extraction fraction (OEF), or thickness after the ophthalmic blood vessels have been closed for a substantial interval and then reopened. We ligated the ophthalmic vessels for 120 minutes in one eye of 17 rats, and measured these variables within 20 minutes after release of the ligature in the 10 rats which had immediate reflow. F, DO2 and MO2 were 5.2 ± 3.1 μL/min, 428 ± 271 nL O2/min, and 234 ± 133 nL O2/min, respectively, that is, to 58%, 46% and 60% of values obtained from normal fellow eyes (P < 0.004). OEF was 0.65 ± 0.23, 148% of normal (P = 0.03). Inner and total retinal thicknesses were 195 ± 24 and 293 ± 20 μm, respectively, 117% and 114% of normal, and inversely related to MO2 (P ≤ 0.02). These results reflect how much energy is available to the retina immediately after an interval of nonperfusion for 120 minutes. Thus, they elucidate aspects of the pathophysiology of nonperfusion retinal injury and may improve therapy in patients with retinal artery or ophthalmic artery obstructions.
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Affiliation(s)
- Norman P Blair
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, USA
| | - Michael R Tan
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, USA
| | - Anthony E Felder
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, USA
| | - Mahnaz Shahidi
- Department of Ophthalmology, University of Southern California, Los Angeles, USA.
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9
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Blixt FW, Haanes KA, Ohlsson L, Dreisig K, Fedulov V, Warfvinge K, Edvinsson L. MEK/ERK/1/2 sensitive vascular changes coincide with retinal functional deficit, following transient ophthalmic artery occlusion. Exp Eye Res 2018; 179:142-149. [PMID: 30439349 DOI: 10.1016/j.exer.2018.11.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/22/2018] [Accepted: 11/05/2018] [Indexed: 11/27/2022]
Abstract
Retinal ischemia remains a major cause of blindness in the world with few acute treatments available. Recent emphasis on retinal vasculature and the ophthalmic artery's vascular properties after ischemia has shown an increase in vasoconstrictive functionality, as previously observed in cerebral arteries following stroke. Specifically, endothelin-1 (ET-1) receptor-mediated vasoconstriction regulated by the MEK/ERK1/2 pathway. In this study, the ophthalmic artery of rats was occluded for 2 h with the middle cerebral artery occlusion model. MEK/ERK1/2 inhibitor U0126 was administered at 0, 6, and 24 h following reperfusion and the functional properties of the ophthalmic artery were evaluated at 48 h post reperfusion. Additionally, retinal function was evaluated at day 1, 4, and 7 after reperfusion. Occlusion of the ophthalmic artery led to a significant increase of endothelin-1 mediated vasoconstriction which can be attenuated by U0126 treatment, most evident at higher ET-1 concentrations of 10-7 M (Emax151.0 ± 22.0% of 60 mM K+), vs non-treated ischemic arteries Emax 212.1 ± 14.7% of 60 mM K+). Retinal function also deteriorated following ischemia and was improved with treatment with a-wave amplitudes of 725 ± 36 μV in control, 560 ± 21 μV in non-treated, and 668 ± 73 μV in U0126 treated at 2 log cd*s/m2 luminance in the acute stages (1 days post-ischemia). Full spontaneous retinal recovery was observed at day 7 regardless of treatment. In conclusion, this is the first study to show a beneficial in vivo effect of U0126 on vascular contractility following ischemia in the ophthalmic artery. Coupled with the knowledge obtained from cerebral vasculature, these results point towards a novel therapeutic approach following ischemia-related injuries to the eye.
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Affiliation(s)
- Frank W Blixt
- Department of Clinical Sciences, Division of Experimental Vascular Research, Lund University, Lund, Sweden.
| | - Kristian Agmund Haanes
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, Glostrup, Denmark
| | - Lena Ohlsson
- Department of Clinical Sciences, Division of Experimental Vascular Research, Lund University, Lund, Sweden
| | - Karin Dreisig
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, Glostrup, Denmark
| | - Vadim Fedulov
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, Glostrup, Denmark
| | - Karin Warfvinge
- Department of Clinical Sciences, Division of Experimental Vascular Research, Lund University, Lund, Sweden; Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, Glostrup, Denmark
| | - Lars Edvinsson
- Department of Clinical Sciences, Division of Experimental Vascular Research, Lund University, Lund, Sweden; Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, Glostrup, Denmark
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10
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Blair NP, Felder AE, Tan MR, Shahidi M. A Model for Graded Retinal Ischemia in Rats. Transl Vis Sci Technol 2018; 7:10. [PMID: 29881647 PMCID: PMC5989761 DOI: 10.1167/tvst.7.3.10] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 04/25/2018] [Indexed: 11/25/2022] Open
Abstract
Purpose Retinal ischemic injury depends on grade and duration of an ischemic insult. We developed a method to induce ischemic injury in rats permitting: (1) Variable grades of retinal blood flow (F) reduction, (2) controllable duration of F reduction, (3) injury without collateral neural damage, and (4) optical measurements of F and O2-related factors: O2 delivery (DO2), O2 extraction fraction (OEF), and metabolic rate of O2 (MO2). Methods In five anesthetized rats the left common carotid artery (CA) was ligated and the right CA was exposed. A variable clamp having a backstop and a rod mounted on a micromanipulator straddled the right CA. Advancing the rod with the micromanipulator produced graded compressions of the CA. F and O2-related factors were measured with established optical techniques. Results Four to seven grades of F for at least 10 minutes were achieved per rat. F decreased only with compressions of over 60%. DO2 changed in proportion to F, particularly at low F. As F decreased, OEF initially changed little, but then rose steeply to its maximum of 1 when F was approximately 4 μL/min. MO2 was stable with reduced F until OEF maximized, after which it decreased progressively. Conclusions This model in rats permits acute, graded inner retinal ischemia that is reversible after prescribed durations, does not otherwise injure the eye and allows optical measurement of important physiologic factors during ischemia. Translational Relevance This model will allow improved understanding of retinal ischemic injury and enable better management of this common, sight-threatening affliction.
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Affiliation(s)
- Norman P Blair
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Anthony E Felder
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Michael R Tan
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Mahnaz Shahidi
- Department of Ophthalmology, University of Southern California, Los Angeles, CA, USA
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11
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Allen RS, Sayeed I, Oumarbaeva Y, Morrison KC, Choi PH, Pardue MT, Stein DG. Progesterone treatment shows greater protection in brain vs. retina in a rat model of middle cerebral artery occlusion: Progesterone receptor levels may play an important role. Restor Neurol Neurosci 2018; 34:947-963. [PMID: 27802245 DOI: 10.3233/rnn-160672] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND/OBJECTIVE To determine whether inflammation increases in retina as it does in brain following middle cerebral artery occlusion (MCAO), and whether the neurosteroid progesterone, shown to have protective effects in both retina and brain after MCAO, reduces inflammation in retina as well as brain. METHODS MCAO rats treated systemically with progesterone or vehicle were compared with shams. Protein levels of cytosolic NF-κB, nuclear NF-κB, phosphorylated NF-κB, IL-6, TNF-α, CD11b, progesterone receptor A and B, and pregnane X receptor were assessed in retinas and brains at 24 and 48 h using western blots. RESULTS Following MCAO, significant increases were observed in the following inflammatory markers: pNF-κB and CD11b at 24 h in both brain and retina, nuclear NF-κB at 24 h in brain and 48 h in retina, and TNF-α at 24 h in brain.Progesterone treatment in MCAO animals significantly attenuated levels of the following markers in brain: pNF-κB, nuclear NF-κB, IL-6, TNF-α, and CD11b, with significantly increased levels of cytosolic NF-κB. Retinas from progesterone-treated animals showed significantly reduced levels of nuclear NF-κB and IL-6 and increased levels of cytosolic NF-κB, with a trend for reduction in other markers. Post-MCAO, progesterone receptors A and B were upregulated in brain and downregulated in retina. CONCLUSION Inflammatory markers increased in both brain and retina after MCAO, with greater increases observed in brain. Progesterone treatment reduced inflammation, with more dramatic reductions observed in brain than retina. This differential effect may be due to differences in the response of progesterone receptors in brain and retina after injury.
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Affiliation(s)
- Rachael S Allen
- Department of Emergency Medicine, Emory University, Atlanta, GA, USA.,Department of Ophthalmology, Emory University, Atlanta, GA, USA.,Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA, USA
| | - Iqbal Sayeed
- Department of Emergency Medicine, Emory University, Atlanta, GA, USA
| | - Yuliya Oumarbaeva
- Department of Emergency Medicine, Emory University, Atlanta, GA, USA
| | | | - Paul H Choi
- Department of Emergency Medicine, Emory University, Atlanta, GA, USA
| | - Machelle T Pardue
- Department of Ophthalmology, Emory University, Atlanta, GA, USA.,Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA, USA
| | - Donald G Stein
- Department of Emergency Medicine, Emory University, Atlanta, GA, USA
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Abstract
Stroke is the fifth leading cause of death and disability in the United States. According to World Heart Federation, every year, 15 million people suffer from stroke worldwide out of which nearly 6 million people die and another 5 million people are disabled. Out of many organs affected after stroke, one of them is eye. Majority of the stroke victims suffer vision loss due to stroke-induced retinal damage. However, stroke-induced retinal damage and microvascular changes have not been given paramount importance in understanding stroke pathophysiology and predicting its occurrence. Retinal imaging can be a very powerful tool to understand and predict stroke. This review will highlight the importance of retinal changes in predicting occurrence of stroke, major retinal changes, the relationship between retinal diseases and stroke and moreover, molecular mechanisms delineating the stroke induced-retinal changes and therapeutics associated with it.
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Affiliation(s)
- Varun Kumar
- Department of Ophthalmology, School of Medicine, Stanford University, Stanford, CA, USA
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13
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Gaidhani N, Sun F, Schreihofer D, Uteshev VV. Duration of isoflurane-based surgical anesthesia determines severity of brain injury and neurological deficits after a transient focal ischemia in young adult rats. Brain Res Bull 2017; 134:168-176. [PMID: 28755978 DOI: 10.1016/j.brainresbull.2017.07.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 07/24/2017] [Accepted: 07/25/2017] [Indexed: 01/26/2023]
Abstract
Tremendous efforts and funds invested in discovery of novel drug treatments for ischemic stroke have so far failed to deliver clinically efficacious therapies. The reasons for these failures are not fully understood. An indiscriminate use of isoflurane-based surgical anesthesia with or without nitrous oxide may act as an unconstrained, untraceable source of data variability, potentially causing false-positive or false-negative results. To test this hypothesis, a common transient suture middle cerebral artery occlusion (tMCAO) model of ischemic stroke in young adult male rats was used to determine the impact of a typical range of anesthesia durations required for this model on data variability (i.e., infarct volume and neurological deficits). The animals were maintained on spontaneous ventilation. The study results indicated that: (1) Variable duration of isoflurane anesthesia prior, during and after tMCAO is a significant source of data variability as evidenced by measurements of infarct volume and neurological deficits; and (2) Severity of brain injury and neurological deficits after tMCAO is inversely related to the duration of isoflurane anesthesia: e.g., in our study, a 90min isoflurane anesthesia nearly completely protected brain tissues from tMCAO-induced injury and thus, would be expected to obscure the effects of stroke treatments in pre-clinical trials. To elevate transparency, rigor and reproducibility of stroke research and minimize undesirable effects of isoflurane on the outcome of novel drug testing, we propose to monitor, minimize and standardize isoflurane anesthesia in experimental surgeries and make anesthesia duration a required reportable parameter in pre-clinical studies. Specifically, we propose to adopt 20-30min as an optimal anesthesia duration that both minimizes neuroprotective effects of isoflurane and permits a successful completion of surgical procedures in a suture tMCAO model of ischemic stroke in rodents. As the mechanisms and neuroprotective, metabolic and immune effects of general anesthesia are not fully understood, the results of this study cannot be blindly generalized to other anesthetics, animal species and experimental models.
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Affiliation(s)
- Nikhil Gaidhani
- University of North Texas Health Science Center, Institute for Healthy Aging, Center for Neuroscience Discovery, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, United States
| | - Fen Sun
- University of North Texas Health Science Center, Institute for Healthy Aging, Center for Neuroscience Discovery, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, United States
| | - Derek Schreihofer
- University of North Texas Health Science Center, Institute for Healthy Aging, Center for Neuroscience Discovery, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, United States
| | - Victor V Uteshev
- University of North Texas Health Science Center, Institute for Healthy Aging, Center for Neuroscience Discovery, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, United States.
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Yang D, So KF, Lo ACY. Lycium barbarum
polysaccharide extracts preserve retinal function and attenuate inner retinal neuronal damage in a mouse model of transient retinal ischaemia. Clin Exp Ophthalmol 2017; 45:717-729. [DOI: 10.1111/ceo.12950] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 02/11/2017] [Accepted: 03/20/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Di Yang
- Department of Ophthalmology, First Affiliated Hospital of Kunming Medical University; Kunming Medical University; Kunming Yunnan China
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong
| | - Kwok-Fai So
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong
- Research Center of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong
| | - Amy CY Lo
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong
- Research Center of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine; The University of Hong Kong; Hong Kong
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Blixt FW, Johansson SE, Johnson L, Haanes KA, Warfvinge K, Edvinsson L. Enhanced Endothelin-1 Mediated Vasoconstriction of the Ophthalmic Artery May Exacerbate Retinal Damage after Transient Global Cerebral Ischemia in Rat. PLoS One 2016; 11:e0157669. [PMID: 27322388 PMCID: PMC4913955 DOI: 10.1371/journal.pone.0157669] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 06/02/2016] [Indexed: 11/18/2022] Open
Abstract
Cerebral vasculature is often the target of stroke studies. However, the vasculature supplying the eye might also be affected by ischemia. The aim of the present study was to investigate if the transient global cerebral ischemia (GCI) enhances vascular effect of endothelin-1 (ET-1) and 5-hydroxytryptamine/serotonin (5-HT) on the ophthalmic artery in rats, leading to delayed retinal damage. This was preformed using myography on the ophthalmic artery, coupled with immunohistochemistry and electroretinogram (ERG) to assess the ischemic consequences on the retina. Results showed a significant increase of ET-1 mediated vasoconstriction at 48 hours post ischemia. The retina did not exhibit any morphological changes throughout the study. However, we found an increase of GFAP and vimentin expression at 72 hours and 7 days after ischemia, indicating Müller cell mediated gliosis. ERG revealed significantly decreased function at 72 hours, but recovered almost completely after 7 days. In conclusion, we propose that the increased contractile response via ET-1 receptors in the ophthalmic artery after 48 hours may elicit negative retinal consequences due to a second ischemic period. This may exacerbate retinal damage after ischemia as illustrated by the decreased retinal function and Müller cell activation. The ophthalmic artery and ET-1 mediated vasoconstriction may be a valid and novel therapeutic target after longer periods of ischemic insults.
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Affiliation(s)
- Frank W. Blixt
- Department of Clinical Sciences, Division of Experimental Vascular Research, Lund University, Lund, Sweden
- * E-mail:
| | - Sara Ellinor Johansson
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, Glostrup, Denmark
| | - Leif Johnson
- Department of Ophthalmology, Glostrup Research Institute, Rigshospitalet, Glostrup, Denmark
| | - Kristian Agmund Haanes
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, Glostrup, Denmark
| | - Karin Warfvinge
- Department of Clinical Sciences, Division of Experimental Vascular Research, Lund University, Lund, Sweden
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, Glostrup, Denmark
| | - Lars Edvinsson
- Department of Clinical Sciences, Division of Experimental Vascular Research, Lund University, Lund, Sweden
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, Glostrup, Denmark
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Cho H, Hartsock MJ, Xu Z, He M, Duh EJ. Monomethyl fumarate promotes Nrf2-dependent neuroprotection in retinal ischemia-reperfusion. J Neuroinflammation 2015; 12:239. [PMID: 26689280 PMCID: PMC4687295 DOI: 10.1186/s12974-015-0452-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 12/04/2015] [Indexed: 12/15/2022] Open
Abstract
Background Retinal ischemia results in neuronal degeneration and contributes to the pathogenesis of multiple blinding diseases. Recently, the fumaric acid ester dimethyl fumarate (DMF) has been FDA-approved for the treatment of multiple sclerosis, based on its neuroprotective and anti-inflammatory effects. Its potential role as a neuroprotective agent for retinal diseases has received little attention. In addition, DMF’s mode of action remains elusive, although studies have suggested nuclear factor erythroid 2-related factor 2 (Nrf2) activation as an important mechanism. Here we investigated the neuroprotective role of monomethyl fumarate (MMF), the biologically active metabolite of DMF, in retinal ischemia-reperfusion (I/R) injury, and examined the role of Nrf2 in mediating MMF action. Methods Wild-type C57BL/6J and Nrf2 knockout (KO) mice were subjected to 90 min of retinal ischemia followed by reperfusion. Mice received daily intraperitoneal injection of MMF. Inflammatory gene expression was measured using quantitative reverse transcription PCR (qRT-PCR) at 48 h after I/R injury. Seven days after I/R, qRT-PCR for Nrf2 target gene expression, immunostaining for Müller cell gliosis and cell loss in the ganglion cell layer (GCL), and electroretinography for retinal function were performed. Results The results of this study confirmed that MMF reduces retinal neurodegeneration in an Nrf2-dependent manner. MMF treatment significantly increased the expression of Nrf2-regulated antioxidative genes, suppressed inflammatory gene expression, reduced Müller cell gliosis, decreased neuronal cell loss in the GCL, and improved retinal function measured by electroretinogram (ERG) after retinal I/R injury in wild-type mice. Importantly, these MMF-mediated beneficial effects were not observed in Nrf2 KO mice. Conclusions These results indicate that fumaric acid esters (FAEs) exert a neuronal protective function in the retinal I/R model and further validate Nrf2 modulation as a major mode of action of FAEs. This suggests that DMF and FAEs could be a potential therapeutic agent for activation of the Nrf2 pathway in retinal and possibly systemic diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12974-015-0452-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hongkwan Cho
- Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 N. Broadway, Baltimore, MD, 21287, USA.
| | - Matthew J Hartsock
- Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 N. Broadway, Baltimore, MD, 21287, USA.
| | - Zhenhua Xu
- Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 N. Broadway, Baltimore, MD, 21287, USA.
| | - Meihua He
- Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 N. Broadway, Baltimore, MD, 21287, USA.
| | - Elia J Duh
- Department of Ophthalmology, Johns Hopkins University School of Medicine, 400 N. Broadway, Baltimore, MD, 21287, USA.
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Allen RS, Olsen TW, Sayeed I, Cale HA, Morrison KC, Oumarbaeva Y, Lucaciu I, Boatright JH, Pardue MT, Stein DG. Progesterone treatment in two rat models of ocular ischemia. Invest Ophthalmol Vis Sci 2015; 56:2880-91. [PMID: 26024074 DOI: 10.1167/iovs.14-16070] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
PURPOSE To determine whether the neurosteroid progesterone, shown to have protective effects in animal models of traumatic brain injury, stroke, and spinal cord injury, is also protective in ocular ischemia animal models. METHODS Progesterone treatment was tested in two ocular ischemia models in rats: a rodent anterior ischemic optic neuropathy (rAION) model, which induces permanent monocular optic nerve stroke, and the middle cerebral artery occlusion (MCAO) model, which causes transient ischemia in both the retina and brain due to an intraluminal filament that blocks the ophthalmic and middle cerebral arteries. Visual function and retinal histology were assessed to determine whether progesterone attenuated retinal injury in these models. Additionally, behavioral testing and 2% 2,3,5-triphenyltetrazolium chloride (TTC) staining in brains were used to compare progesterone's neuroprotective effects in both retina and brain using the MCAO model. RESULTS Progesterone treatment showed no effect on visual evoked potential (VEP) reduction and retinal ganglion cell loss in the permanent rAION model. In the transient MCAO model, progesterone treatment reduced (1) electroretinogram (ERG) deficits, (2) MCAO-induced upregulation of glutamine synthetase (GS) and glial fibrillary acidic protein (GFAP), and (3) retinal ganglion cell loss. As expected, progesterone treatment also had significant protective effects in behavioral tests and a reduction in infarct size in the brain. CONCLUSIONS Progesterone treatment showed protective effects in the retina following MCAO but not rAION injury, which may result from mechanistic differences with injury type and the therapeutic action of progesterone.
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Affiliation(s)
- Rachael S Allen
- Emergency Medicine Emory University, Atlanta, Georgia, United States 2Department of Ophthalmology, Emory University, Atlanta, Georgia, United States 3Atlanta VA Center for Visual and Neurocognitive Rehabilitation, Decatur, Georgia, United States
| | - Timothy W Olsen
- Department of Ophthalmology, Emory University, Atlanta, Georgia, United States
| | - Iqbal Sayeed
- Emergency Medicine Emory University, Atlanta, Georgia, United States
| | - Heather A Cale
- Emergency Medicine Emory University, Atlanta, Georgia, United States
| | | | - Yuliya Oumarbaeva
- Emergency Medicine Emory University, Atlanta, Georgia, United States
| | - Irina Lucaciu
- Emergency Medicine Emory University, Atlanta, Georgia, United States
| | - Jeffrey H Boatright
- Department of Ophthalmology, Emory University, Atlanta, Georgia, United States 3Atlanta VA Center for Visual and Neurocognitive Rehabilitation, Decatur, Georgia, United States
| | - Machelle T Pardue
- Department of Ophthalmology, Emory University, Atlanta, Georgia, United States 3Atlanta VA Center for Visual and Neurocognitive Rehabilitation, Decatur, Georgia, United States
| | - Donald G Stein
- Emergency Medicine Emory University, Atlanta, Georgia, United States
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18
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Huang Y, Fan S, Li J, Wang YL. Bilateral Common Carotid Artery Occlusion in the Rat as a Model of Retinal Ischaemia. Neuroophthalmology 2014; 38:180-188. [PMID: 27928297 DOI: 10.3109/01658107.2014.908928] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Revised: 03/11/2014] [Accepted: 03/17/2014] [Indexed: 11/13/2022] Open
Abstract
Ocular ischaemic syndrome is a devastating eye disease caused by severe carotid artery stenosis. The purpose of the study was to develop a reliable rat model for this syndrome by means of common carotid artery occlusion and a controllable needle suture method. Adult Wistar rats were subjected to common carotid artery occlusion and sham surgery. The common carotid artery was ligated unilaterally or bilaterally with needles of different diameters, and ocular arterial filling time was examined by fluorescein fundus angiography at different time points. Haematoxylin-eosin staining of vessels and degree of stenosis were considered outcome measures. The ocular blood flow was monitored and measured by laser doppler flowmetry. Needles with a diameter of 0.4 mm were more effective in developing severe stenosis of the common carotid arteries compared with needles of other diameters. Bilateral common carotid artery occlusion was a more effective model than unilateral occlusion. The arterial filling time was significantly increased at 14 and 21 days after ligation (5.75 ± 0.45 and 6.27 ± 0.95 s, respectively) compared with arterial filling time before surgery (5.22 ± 0.64 s). The total blood flow in the sham surgery group was significantly higher than in the bilateral common carotid artery occlusion group. The fundus blood flow was statistically different between the two groups, whereas that of the anterior segment was not. In conclusion, the authors have established a rat model of ocular ischaemic syndrome via a controllable needle suture method, which was reliable up to 2-3 weeks after surgery.
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Affiliation(s)
- Yingxiang Huang
- Department of Ophthalmology, Beijing Friendship Hospital affiliated to Capital Medical University Beijing China
| | - Shichao Fan
- Department of Ophthalmology, Beijing Friendship Hospital affiliated to Capital Medical University Beijing China
| | - Jun Li
- Peking University Laboratory Animal Centre, Peking University China
| | - Yan-Ling Wang
- Department of Ophthalmology, Beijing Friendship Hospital affiliated to Capital Medical University Beijing China
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19
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Protective effects of remote ischemic conditioning against ischemia/reperfusion-induced retinal injury in rats. Vis Neurosci 2014; 31:245-52. [DOI: 10.1017/s0952523814000121] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
AbstractLimb remote ischemic conditioning (LRIC) provides a physiologic strategy for harnessing the body’s endogenous protective capabilities against injury induced by ischemia–reperfusion in the central nervous system. The aim of the present study was to determine if LRIC played a role in protecting the retina from ischemia–reperfusion injury. A total of 81 adult male Sprague-Dawley rats were randomly assigned to sham and ischemia/reperfusion with or without remote LRIC arms. The retinal ischemic model was generated through right middle cerebral artery occlusion (MCAO) and pterygopalatine artery occlusion for 60 min followed by 1, 3, and 7 days of subsequent reperfusion. LRIC was conducted immediately following MCAO by tightening a tourniquet around the upper thigh and releasing for three cycles. Paraffin sections were stained with hematoxylin and eosin in order to quantify the number of cells in retinal ganglion cells (RGCs) layer throughout the duration of the study. Cellular expression of glial fibrillary acidic protein (GFAP) was detected and examined through immunohistochemistry. Protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) was also analyzed by Western blot techniques. Our study demonstrated that the loss of cells in RGC layer was attenuated by LRIC treatment at 3 and 7 days following reperfusion (P < 0.05). Immunohistochemistry studies depicted a gradual increase (P < 0.05) in GFAP levels from day 1 through day 7 following ischemia and subsequent reperfusion, whereas LRIC reduced GFAP levels at 1, 3, and 7 days postreperfusion. In addition, LRIC increased the expression of Nrf2 and HO-1 at day 1 and 3 following ischemia/reperfusion. This particular study is the first remote conditioning study applicable to retinal ischemia. Our results strongly support the position that LRIC may be used as a noninvasive neuroprotective strategy, which provides retinal protection from ischemia–reperfusion injury through the upregulation of antioxidative stress proteins, such as Nrf2 and HO-1.
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20
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Allen RS, Sayeed I, Cale HA, Morrison KC, Boatright JH, Pardue MT, Stein DG. Severity of middle cerebral artery occlusion determines retinal deficits in rats. Exp Neurol 2014; 254:206-15. [PMID: 24518488 DOI: 10.1016/j.expneurol.2014.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 01/16/2014] [Accepted: 02/02/2014] [Indexed: 10/25/2022]
Abstract
Middle cerebral artery occlusion (MCAO) using the intraluminal suture technique is a common model used to study cerebral ischemia in rodents. Due to the proximity of the ophthalmic artery to the middle cerebral artery, MCAO blocks both arteries, causing both cerebral ischemia and retinal ischemia. While previous studies have shown retinal dysfunction at 48h post-MCAO, we investigated whether these retinal function deficits persist until 9days and whether they correlate with central neurological deficits. Rats received 90min of transient MCAO followed by electroretinography at 2 and 9days to assess retinal function. Retinal damage was assessed with cresyl violet staining, immunohistochemistry for glial fibrillary acidic protein (GFAP) and glutamine synthetase, and TUNEL staining. Rats showed behavioral deficits as assessed with neuroscore that correlated with cerebral infarct size and retinal function at 2days. Two days after surgery, rats with moderate MCAO (neuroscore <5) exhibited delays in electroretinogram implicit time, while rats with severe MCAO (neuroscore ≥5) exhibited reductions in amplitude. Glutamine synthetase was upregulated in Müller cells 3days after MCAO in both severe and moderate animals; however, retinal ganglion cell death was only observed in MCAO retinas from severe animals. By 9days after MCAO, both glutamine synthetase labeling and electroretinograms had returned to normal levels in moderate animals. Early retinal function deficits correlated with behavioral deficits. However, retinal function decreases were transient, and selective retinal cell loss was observed only with severe ischemia, suggesting that the retina is less susceptible to MCAO than the brain. Temporary retinal deficits caused by MCAO are likely due to ischemia-induced increases in extracellular glutamate that impair signal conduction, but resolve by 9days after MCAO.
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Affiliation(s)
- Rachael S Allen
- Emergency Medicine, Emory University, Atlanta, GA 30322, USA; Ophthalmology, Emory University, Atlanta, GA 30322, USA.
| | - Iqbal Sayeed
- Emergency Medicine, Emory University, Atlanta, GA 30322, USA.
| | - Heather A Cale
- Emergency Medicine, Emory University, Atlanta, GA 30322, USA.
| | | | | | - Machelle T Pardue
- Ophthalmology, Emory University, Atlanta, GA 30322, USA; Rehab R&D Center of Excellence, Atlanta VA Medical Center, Decatur, GA 30033, USA.
| | - Donald G Stein
- Emergency Medicine, Emory University, Atlanta, GA 30322, USA.
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21
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Xiao J, Zhou X, Jiang T, Zhi ZN, Li Q, Qu J, Chen JG. Unilateral cerebral ischemia inhibits optomotor responses of the ipsilateral eye in mice. J Integr Neurosci 2012; 11:193-200. [PMID: 22744825 DOI: 10.1142/s0219635212500148] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 02/03/2012] [Indexed: 11/18/2022] Open
Abstract
A reduction in blood flow to the brain causes stroke and damage to neuronal networks. Cerebral ischemia is frequently associated with loss of visual functions. Because retinal and small cerebral vessels are vulnerable to similar risk factors, the loss of vision could result from concurrent retinal ischemia, and it is not clear if visual functions may be inhibited by cerebral ischemia directly. In this study, the distal middle cerebral artery in the right hemisphere of mice was occluded to produce unilateral cerebral ischemia and subsequent infarction. The layer V neurons expressing YFP in transgenic yellow fluorescent protein in transgenic B6.Cg-Tg(Thy1-YFPH)2Jrs/J mice disappeared in the motor and somatosensory cortex, but not in the visual area. The latencies of flash visual evoked potential recorded from two hemispheres were imbalanced, but did not differ markedly from the latencies recorded in controls. However, the optomotor responses of the ipsilateral eye were significantly reduced by 48 h after occlusion. Our results suggest that focused cerebral ischemia may inhibit ipsilateral eye movement in the absence of damage to the visual cortex. This study may provide a platform for further investigation of the relationship between cortical ischemia and visual function.
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Affiliation(s)
- Jian Xiao
- State Key Laboratory Cultivation Base, Ministry of Health, School of Ophthalmology and Optometry, Wenzhou Medical College, Zhejiang, PR China
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22
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Minhas G, Morishita R, Anand A. Preclinical models to investigate retinal ischemia: advances and drawbacks. Front Neurol 2012; 3:75. [PMID: 22593752 PMCID: PMC3350026 DOI: 10.3389/fneur.2012.00075] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 04/16/2012] [Indexed: 12/17/2022] Open
Abstract
Retinal ischemia is a major cause of blindness worldwide. It is associated with various disorders such as diabetic retinopathy, glaucoma, optic neuropathies, stroke, and other retinopathies. Retinal ischemia is a clinical condition that occurs due to lack of appropriate supply of blood to the retina. As the retina has a higher metabolic demand, any hindrance in the blood supply to it can lead to decreased supply of oxygen, thus causing retinal ischemia. The pathology of retinal ischemia is still not clearly known. To get a better insight into the pathophysiology of retinal ischemia, the role of animal models is indispensable. The standard treatment care for retinal ischemia has limited potential. Transplantation of stem cells provide neuroprotection and to replenish damaged cells is an emerging therapeutic approach to treat retinal ischemia. In this review we provide an overview of major animal models of retinal ischemia along with the current and preclinical treatments in use.
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Affiliation(s)
- Gillipsie Minhas
- Neuroscience Research Lab, Department of Neurology, Postgraduate Institute of Medical Education and ResearchChandigarh, India
| | - Ryuichi Morishita
- Division of Clinical Gene Therapy, Graduate School of Medicine, Osaka University Medical SchoolOsaka, Japan
| | - Akshay Anand
- Neuroscience Research Lab, Department of Neurology, Postgraduate Institute of Medical Education and ResearchChandigarh, India
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Muthaian R, Minhas G, Anand A. Pathophysiology of stroke and stroke-induced retinal ischemia: emerging role of stem cells. J Cell Physiol 2012; 227:1269-79. [PMID: 21989824 DOI: 10.1002/jcp.23048] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The current review focuses on pathophysiology, animal models and molecular analysis of stroke and retinal ischemia, and the role of stem cells in recovery of these disease conditions. Research findings associated with ischemic stroke and retinal ischemia have been discussed, and efforts towards prevention and limiting the recurrence of ischemic diseases, as well as emerging treatment possibilities with endothelial progenitor cells (EPCs) in ischemic diseases, are presented. Although most neurological diseases are still not completely understood and reliable treatment is lacking, animal models provide a major step in validating novel therapies. Stem cell approaches constitute an emerging form of cell-based therapy to treat ischemic diseases since it is an attractive source for regenerative therapy in the ischemic diseases. In this review, we highlight the advantages and limitations of this approach with a focus on key observations from preclinical animal studies and clinical trials. Further research, especially on treatment with EPCs is warranted.
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Affiliation(s)
- Rupadevi Muthaian
- Department of Neurology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
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24
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Selective over-expression of endothelin-1 in endothelial cells exacerbates inner retinal edema and neuronal death in ischemic retina. PLoS One 2011; 6:e26184. [PMID: 22053184 PMCID: PMC3203861 DOI: 10.1371/journal.pone.0026184] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 09/22/2011] [Indexed: 11/19/2022] Open
Abstract
The level of endothelin-1 (ET-1), a potent vasoconstrictor, was associated with retinopathy under ischemia. The effects of endothelial endothelin-1 (ET-1) over-expression in a transgenic mouse model using Tie-1 promoter (TET-1 mice) on pathophysiological changes of retinal ischemia were investigated by intraluminal insertion of a microfilament up to middle cerebral artery (MCA) to transiently block the ophthalmic artery. Two-hour occlusion and twenty-two-hour reperfusion were performed in homozygous (Hm) TET-1 mice and their non-transgenic (NTg) littermates. Presence of pyknotic nuclei in ganglion cell layer (GCL) was investigated in paraffin sections of ipsilateral (ischemic) and contralateral (non-ischemic) retinae, followed by measurement of the thickness of inner retinal layer. Moreover, immunocytochemistry of glial fibrillary acidic protein (GFAP), glutamine synthetase (GS) and aquaporin-4 (AQP4) peptides on retinal sections were performed to study glial cell reactivity, glutamate metabolism and water accumulation, respectively after retinal ischemia. Similar morphology was observed in the contralateral retinae of NTg and Hm TET-1 mice, whereas ipsilateral retina of NTg mice showed slight structural and cellular changes compared with the corresponding contralateral retina. Ipsilateral retinae of Hm TET-1 mice showed more significant changes when compared with ipsilateral retina of NTg mice, including more prominent cell death in GCL characterized by the presence of pyknotic nuclei, elevated GS immunoreactivity in Müller cell bodies and processes, increased AQP-4 immunoreactivity in Müller cell processes, and increased inner retinal thickness. Thus, over-expression of endothelial ET-1 in TET-1 mice may contribute to increased glutamate-induced neurotoxicity on neuronal cells and water accumulation in inner retina leading to edema.
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25
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Esfandiari A, Yousof A, Aliabadi A. The Survey of Effects of Unilateral Ligation of Common Carotid Artery on Ultra Structural of Photoreceptor Cells of Retina in Dog. ACTA ACUST UNITED AC 2010. [DOI: 10.3923/ajava.2010.246.252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Kalesnykas G, Tuulos T, Uusitalo H, Jolkkonen J. Neurodegeneration and cellular stress in the retina and optic nerve in rat cerebral ischemia and hypoperfusion models. Neuroscience 2008; 155:937-47. [DOI: 10.1016/j.neuroscience.2008.06.038] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Revised: 06/12/2008] [Accepted: 06/12/2008] [Indexed: 11/30/2022]
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27
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Steele EC, Guo Q, Namura S. Filamentous middle cerebral artery occlusion causes ischemic damage to the retina in mice. Stroke 2008; 39:2099-104. [PMID: 18436885 DOI: 10.1161/strokeaha.107.504357] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Filamentous middle cerebral artery occlusion (fMCAO) is the most frequently used focal cerebral ischemia model in rodents. The proximity of the ophthalmic artery to the middle cerebral artery suggests that fMCAO induces retinal ischemia. We therefore tested whether fMCAO induces ischemia/reperfusion damage in retina in mice. METHODS SV129EV mice were subjected to transient (30 or 60 minutes) fMCAO followed by reperfusion under isoflurane anesthesia. Retinal perfusion was evaluated by intravenous injection of fluorescent microspheres combined with fluorescent microscopy using flat-mounted retinas. The fluorescent density of ipsilateral retina relative to contralateral retina was determined in each animal. Retinal injury was assessed by cresyl violet staining and in situ TUNEL. RESULTS Microsphere analysis demonstrated perfusion defect in the ipsilateral retina after 60 minutes fMCAO and effective restoration after reperfusion. Thirty minutes fMCAO did not produce evident histological changes, even after 2 days of reperfusion. Sixty minutes fMCAO followed by 2 hours reperfusion resulted in extensive cell damage in the inner nuclear (>30%) and ganglion cell (>50%) layers. TUNEL demonstrated very few positive cells, suggesting that damaged cells were mainly undergoing nonapoptotic cell death. CONCLUSIONS Sixty minutes fMCAO produces retinal injury in SV129EV mice. Potential visual dysfunction should be considered when a particular occlusion period is selected for studying neurological outcomes after fMCAO. Because visual disturbance is often associated with thrombotic/embolic stroke in humans, fMCAO represents an appropriate model for future studies aimed at understanding and ameliorating the changes that lead to retinal damage in these patients.
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Affiliation(s)
- Ernest C Steele
- Department of Anatomy and Neurobiology, Morehouse School of Medicine, 720 Westview Dr SW, Atlanta, GA 30310, USA
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Cheung AKH, Lo ACY, So KF, Chung SSM, Chung SK. Gene deletion and pharmacological inhibition of aldose reductase protect against retinal ischemic injury. Exp Eye Res 2007; 85:608-16. [PMID: 17727843 DOI: 10.1016/j.exer.2007.07.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 07/16/2007] [Accepted: 07/17/2007] [Indexed: 01/26/2023]
Abstract
Retinal ischemic injury is common in patients with diabetes, atherosclerosis, hypertension, transient ischemia attack and amaurosis fugax. Previously, signs of ischemic stress, such as pericyte loss, blood-retinal barrier breakdown and neovascularization, which can lead to occlusion of retinal vessels, have been prevented in diabetic db/db mice with aldose reductase (AR) null mutation. To determine the role in retinal ischemic injury of AR and sorbitol dehydrogenase (SDH), the first and second enzymes in the polyol pathway, mice with deletion of AR (AR(-/-)) or SDH-mutation (SDH(-/-)), or C57BL/6N mice treated with AR or SDH inhibitors were subjected to transient retinal artery occlusion (2h of occlusion and 22h of reperfusion) by the intraluminal suture method. Neuronal loss and edema observed in wildtype (AR(+/+)) retinas after transient ischemia were prevented in the retinas of AR(-/-) mice or C57BL/6N mice treated with an AR inhibitor, Fidarestat. Fewer TUNEL-positive cells and smaller accumulations of nitrotyrosine and poly(ADP-ribose) were also observed in the retinas of AR(-/-) mice. However, SDH(-/-) mice and C57BL/6N mice treated with SDH inhibitor, CP-470,711, were not protected against ischemia-induced retinal damage. Taken together, AR contributes to retinal ischemic injury through increased edema and free radical accumulation. Therefore, AR inhibition should be considered for the treatment of retinal ischemic injury often observed in diabetic patients.
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Affiliation(s)
- Alvin K H Cheung
- Department of Anatomy, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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