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Nordahl KML, Fedulov V, Holm A, Haanes KA. Intraocular Adeno-Associated Virus-Mediated Transgene Endothelin-1 Delivery to the Rat Eye Induces Functional Changes Indicative of Retinal Ischemia-A Potential Chronic Glaucoma Model. Cells 2023; 12:1987. [PMID: 37566067 PMCID: PMC10417058 DOI: 10.3390/cells12151987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/19/2023] [Accepted: 07/25/2023] [Indexed: 08/12/2023] Open
Abstract
Endothelin-1 (ET-1) overactivity has been implicated as a factor contributing to glaucomatous neuropathy, and it has been utilized in animal models of retinal ischemia. The functional effects of long-term ET-1 exposure and possible compensatory mechanisms have, however, not been investigated. This was therefore the purpose of our study. ET-1 was delivered into rat eyes via a single intravitreal injection of 500 µM or via transgene delivery using an adeno-associated viral (AAV) vector. Retinal function was assessed using electroretinography (ERG) and the retinal expression of potentially compensatory genes was evaluated by means of qRT-PCR. Acute ET-1 delivery led to vasoconstriction and a significant reduction in the ERG response. AAV-ET-1 resulted in substantial transgene expression and ERG results similar to the acute ET-1 injections and comparable to other models of retinal ischemia. Compensatory changes were observed, including an increase in calcitonin gene-related peptide (CGRP) gene expression, which may both counterbalance the vasoconstrictive effects of ET-1 and provide neuroprotection. This chronic ET-1 ischemia model might be especially relevant to glaucoma research, mimicking the mild and repeated ischemic events in patients with long-term vascular dysfunction. The compensatory mechanisms, and particularly the role of vasodilatory CGRP in mitigating the retinal damage, warrant further investigation with the aim of evaluating new therapeutic strategies.
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Affiliation(s)
- Karin M. L. Nordahl
- Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, 2600 Glostrup, Denmark; (A.H.); (K.A.H.)
| | - Vadim Fedulov
- Clinical and Medical Affairs, Radiometer, 2700 Brønshøj, Denmark;
| | - Anja Holm
- Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, 2600 Glostrup, Denmark; (A.H.); (K.A.H.)
- Center for RNA Medicine, Department of Clinical Medicine, Aalborg University, 2450 Copenhagen, Denmark
| | - Kristian A. Haanes
- Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet, 2600 Glostrup, Denmark; (A.H.); (K.A.H.)
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Fedulov V, Rex CS, Simmons DA, Palmer L, Gall CM, Lynch G. Evidence that long-term potentiation occurs within individual hippocampal synapses during learning. J Neurosci 2007; 27:8031-9. [PMID: 17652593 PMCID: PMC6672739 DOI: 10.1523/jneurosci.2003-07.2007] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Stabilization of long-term potentiation (LTP) depends on multiple signaling cascades linked to actin polymerization. We used one of these, involving phosphorylation of the regulatory protein cofilin, as a marker to test whether LTP-related changes occur in hippocampal synapses during unsupervised learning. Well handled rats were allowed to explore a compartmentalized environment for 30 min after an injection of vehicle or the NMDA receptor antagonist (+/-)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP). Another group of rats consisted of vehicle-injected, home-cage controls. Vehicle-treated rats that explored the environment had 30% more spines with dense phosphorylated (p) cofilin immunoreactivity in hippocampal field CA1 than did rats in the home-cage group. The increase in pCofilin-positive spines and behavioral evidence for memory of the explored environment were both eliminated by CPP. Coimmunostaining for pCofilin and the postsynaptic density protein 95 (PSD-95) showed that synapses on pCofilin-positive spines were substantially larger than those on neighboring (pCofilin-negative) spines. These results establish that uncommon cellular events associated with LTP, including changes in synapse size, occur in individual spines during learning, and provide a technique for mapping potential engrams.
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Affiliation(s)
| | | | - Danielle A. Simmons
- Psychiatry and Human Behavior, University of California, Irvine, California 92617-4291, and
| | - Linda Palmer
- Department of Philosophy, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
| | - Christine M. Gall
- Departments of Anatomy and Neurobiology
- Neurobiology and Behavior, and
| | - Gary Lynch
- Psychiatry and Human Behavior, University of California, Irvine, California 92617-4291, and
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Keirstead HS, Fedulov V, Cloutier F, Steward O, Duel BP. A noninvasive ultrasonographic method to evaluate bladder function recovery in spinal cord injured rats. Exp Neurol 2005; 194:120-7. [PMID: 15899249 DOI: 10.1016/j.expneurol.2005.01.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Revised: 12/08/2004] [Accepted: 01/04/2005] [Indexed: 11/17/2022]
Abstract
Suprasacral spinal cord injury induces changes in the mechanical and neuronal properties of the bladder resulting in bladder areflexia followed by bladder-sphincter dyssynergia and detrusor muscle hypertrophy, which lead to urinary retention and increased bladder size. These changes are most often quantified using highly skilled urodynamic techniques that involve catheterization. We investigated whether a hand-held digital ultrasound imaging system could monitor urinary retention in the bladder following spinal cord injury in adult rats. Our findings indicate that contusive spinal cord injury resulted in high residual bladder volumes that decreased and stabilized by 2 weeks post-injury but remained significantly higher than control bladder volumes up to 46 days post-injury (the longest time point examined). Post hoc analysis indicated that the degree of bladder function recovery recorded at the end of the study correlated with the degree of bladder function recovery recorded at 6 days post-injury, indicating that bladder function recovery can be predicted by analyzing bladder volume as early as 6 days post-injury. Bladder function recovery correlated with locomotor recovery as assessed using the BBB locomotor rating scale. While providing a noninvasive assessment of bladder function with no detrimental impact on locomotor function or assessment, this protocol provides researchers with a clinically relevant outcome measure for quantifying bladder function recovery after spinal cord injury or after experimental treatments for spinal cord injury.
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Affiliation(s)
- Hans S Keirstead
- Reeve-Irvine Research Center, Department of Anatomy and Neurobiology, 2111 Gillespie Neuroscience Research Facility, College of Medicine, University of California Irvine, Irvine, CA 92697-4292, USA.
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