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Blair NP, Matei N, Leahy S, Rahimi M, Shahidi M. The accumulated oxygen deficit as an indicator of the ischemic retinal insult. Exp Eye Res 2023; 230:109439. [PMID: 36931487 PMCID: PMC10133208 DOI: 10.1016/j.exer.2023.109439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 02/24/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023]
Abstract
We here attempt to improve quantification of the ischemic retinal insult, that is, what is imposed on the retinal tissue by ischemia, especially in experimental models of ischemia. The ischemic retinal insult initiates the ischemic retinal injury (or outcome). Accordingly, it is reasonable to assume that the better the quantification of the insult, the better the correlation with, and thereby estimation of, the injury. The insult seldom has been quantified in terms of the relevant physiological factors, especially in connection with the rate of oxygen delivery (DO2). We here propose the accumulated oxygen deficit (AO2D) as an indicator of the ischemic retinal insult. We hypothesized that AO2D is correlated with the rate of oxygen metabolism measured 1 h after reperfusion following an episode of ischemia (MO2_1_Hr). Previously, we showed that MO2_1_Hr is related to the electroretinogram amplitude and the retinal thickness when they are measured seven days after reperfusion. We studied 27 rats, as well as 26 rats from our published data on retinal ischemia in which we had measurements of DO2 and duration of ischemia (T) of various levels and durations. We also measured DO2 in 29 rats treated with sham surgery. Ischemia was induced by either ipsilateral or bilateral common carotid artery occlusion or by ophthalmic artery occlusion, which gave a wide range of DO2. DO2 and MO2_1_Hr were evaluated based on three types of images: 1) red-free images to measure vessel diameters, 2) fluorescence images to estimate blood velocities by the displacement of intravascular fluorescent microspheres over time, and 3) phosphorescence images to quantify vascular oxygen tension from the phosphorescence lifetime of an intravascular oxygen sensitive phosphor. Loss of oxygen delivery (DO2L) was calculated as the difference between DO2 under normal/sham condition and DO2 during ischemia. AO2D, a volume of oxygen, was calculated as the product DO2L and T. Including all data, the linear relationship between AO2D and MO2_1_Hr was significant (R2 = 0.261, P = 0.0003). Limiting data to that in which T or DO2L was maximal also yielded significant relationships, and revealed that DO2L at a long duration of ischemia contributed disproportionately more than T to MO2_1_Hr. We discuss the potential of AO2D for quantifying the ischemic retinal insult, predicting the ischemic retinal injury and evaluating the likelihood of infarction.
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Affiliation(s)
- Norman P Blair
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1855 West Taylor Street, Chicago, IL 60612, USA.
| | - Nathanael Matei
- Department of Ophthalmology, University of Southern California, 1450 San Pablo St, Suite 4700, Los Angeles, CA 9003, USA.
| | - Sophie Leahy
- Department of Ophthalmology, University of Southern California, 1450 San Pablo St, Suite 4700, Los Angeles, CA 9003, USA.
| | - Mansour Rahimi
- Department of Ophthalmology, University of Southern California, 1450 San Pablo St, Suite 4700, Los Angeles, CA 9003, USA.
| | - Mahnaz Shahidi
- Department of Ophthalmology, University of Southern California, 1450 San Pablo St, Suite 4700, Los Angeles, CA 9003, USA.
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2
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Franco R, Lillo A, Rivas-Santisteban R, Reyes-Resina I, Navarro G. Microglial Adenosine Receptors: From Preconditioning to Modulating the M1/M2 Balance in Activated Cells. Cells 2021; 10:1124. [PMID: 34066933 PMCID: PMC8148598 DOI: 10.3390/cells10051124] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/19/2021] [Accepted: 05/01/2021] [Indexed: 12/14/2022] Open
Abstract
Neuronal survival depends on the glia, that is, on the astroglial and microglial support. Neurons die and microglia are activated not only in neurodegenerative diseases but also in physiological aging. Activated microglia, once considered harmful, express two main phenotypes: the pro-inflammatory or M1, and the neuroprotective or M2. When neuroinflammation, i.e., microglial activation occurs, it is important to achieve a good M1/M2 balance, i.e., at some point M1 microglia must be skewed into M2 cells to impede chronic inflammation and to afford neuronal survival. G protein-coupled receptors in general and adenosine receptors in particular are potential targets for increasing the number of M2 cells. This article describes the mechanisms underlying microglial activation and analyzes whether these cells exposed to a first damaging event may be ready to be preconditioned to better react to exposure to more damaging events. Adenosine receptors are relevant due to their participation in preconditioning. They can also be overexpressed in activated microglial cells. The potential of adenosine receptors and complexes formed by adenosine receptors and cannabinoids as therapeutic targets to provide microglia-mediated neuroprotection is here discussed.
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Affiliation(s)
- Rafael Franco
- CiberNed, Network Research Center, Neurodegenerative Diseases, Spanish National Health Institute Carlos III, 28034 Madrid, Spain;
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, 08028 Barcelona, Spain
| | - Alejandro Lillo
- Department of Biochemistry and Physiology, Faculty of Pharmacy and Food Science, University of Barcelona, 08028 Barcelona, Spain;
| | - Rafael Rivas-Santisteban
- CiberNed, Network Research Center, Neurodegenerative Diseases, Spanish National Health Institute Carlos III, 28034 Madrid, Spain;
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, 08028 Barcelona, Spain
| | - Irene Reyes-Resina
- CiberNed, Network Research Center, Neurodegenerative Diseases, Spanish National Health Institute Carlos III, 28034 Madrid, Spain;
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, 08028 Barcelona, Spain
| | - Gemma Navarro
- CiberNed, Network Research Center, Neurodegenerative Diseases, Spanish National Health Institute Carlos III, 28034 Madrid, Spain;
- Department of Biochemistry and Physiology, Faculty of Pharmacy and Food Science, University of Barcelona, 08028 Barcelona, Spain;
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3
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Singh BL, Chen L, Cai H, Shi H, Wang Y, Yu C, Chen X, Han X, Cai X. Activation of adenosine A2a receptor accelerates and A2a receptor antagonist reduces intermittent hypoxia induced PC12 cell injury via PKC-KATP pathway. Brain Res Bull 2019; 150:118-126. [PMID: 31129168 DOI: 10.1016/j.brainresbull.2019.05.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/19/2019] [Accepted: 05/21/2019] [Indexed: 02/07/2023]
Abstract
Obstructive sleep apnea hypopnea syndrome (OSAHS) is associated with multiple system diseases. Neurocognitive dysfunction resulting from central nervous system complications has been reported, especially in children with OSAHS. Chronic intermittent hypoxia is accepted to be the major pathophysiological mechanism of OSAHS. Adenosine plays an important role in cellular function via interactions with its receptors. A2a receptor has been recognized as a factor involved in neuroprotection. However, the role of adenosine A2a receptor in intermittent hypoxia induced cellular injury is not completely understood. In this study, we aim to investigate the underlying mechanisms of A2a receptor mediated cellular damage caused by intermittent hypoxia in PC12 cells. We found that activated A2a receptor by CGS21680 decreased cellular viability, increased PKC as well as ATP-sensitive potassium channel (KATP) subunits expression Kir6.2 and SUR1. Inhibition of A2a receptor by SCH58261 increased cellular viability, suppressed PKC and SUR1 expression level, ultimately showing a protective role in PC12 cells. Moreover, we observed that CHE, which is an antagonist of PKC, downregulated Kir6.2 and SUR1 expression and increased cellular viability. Additionally, we found that A2a receptor activation induced cell injury was associated with increased Cleaved-Caspase 3 expression, which can be decreased by inhibition of A2a receptor or PKC. In conclusion, our findings indicate that A2a receptor induced KATP expression by PKC activation and plays a role in accelerating PC12 cells injury induced by intermittent hypoxia exposure via A2a-PKC-KATP signal pathway mediated apoptosis.
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Affiliation(s)
- Brett Lyndall Singh
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, PR China; The Second School Of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Liya Chen
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, PR China; The Second School Of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Huilin Cai
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, PR China; The Second School Of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Hua Shi
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, PR China; The Second School Of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Yueyuan Wang
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, PR China; The Second School Of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Chenyi Yu
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, PR China
| | - Xu Chen
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, PR China
| | - Xinru Han
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, PR China; The Second School Of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Xiaohong Cai
- Department of Pediatrics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, 109 Xueyuan Western Road, Wenzhou, Zhejiang, 325027, PR China; The Second School Of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, PR China.
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4
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Abstract
Adenosine is a neuromodulator present in various areas of the central nervous system, including the retina. Adenosine may serve a neuroprotective role in the retina, based on electroretinogram (ERG) recordings from the rat retina. Our purpose was to assess the role of A2A and A3 adenosine receptors in the generation and modulation of the rat ERG. The flash ERG was recorded with corneal electrodes from Sprague Dawley rats. Agonists and antagonists for A2A and A3 receptors, and adenosine were injected (5 µl) into the vitreous. The effects on the components of the single flash scotopic and photopic ERGs were examined, and ERG flicker. Adenosine (0.5 mM) increased the mean amplitudes of the scotopic ERG a-waves (68 ± 8 to 97 ± 14 µV, P = 0.042), and b-waves (236 ± 38 µV to 305 ± 42 µV). A2A agonist CGS21680 (2 mM) reduced the mean amplitude of the ERG b-wave, from 298 ± 21 µV in response to the brightest stimulus to 212 ± 19 µV (P = 0.005), and mean scotopic oscillatory potentials (OPs) from 100 ± 9 µV to 47 ± 11 µV (P = 0.023). ZM241385 [4 mM], an A2A antagonist, decreased the scotopic b-wave of the ERG. A3 agonist 2-CI-IB-MECA (0.5 mM) increased the a-wave, while decreasing the scotopic and photopic ERG b-waves, and the scotopic OPs. A3 antagonist VUF5574 (1 mM) increased the mean amplitude of the scotopic a-wave (66 ± 8 to 140 ± 29 µV, P = 0.046) and b-wave (224 ± 20 to 312 ± 39 µV, P = 0.0037). No significant effects on ERG flicker were found. We conclude that retinal neurons containing A2A and/or A3 adenosine receptors contribute to the generation of the ERG a- and b-waves and OPs.
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5
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Rex TS, Reilly MA, Sponsel WE. Elucidating the effects of primary blast on the eye. Clin Exp Ophthalmol 2015; 43:197-9. [PMID: 25923380 DOI: 10.1111/ceo.12502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Tonia S Rex
- Vanderbilt Eye Institute, Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
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Dos Santos-Rodrigues A, Pereira MR, Brito R, de Oliveira NA, Paes-de-Carvalho R. Adenosine transporters and receptors: key elements for retinal function and neuroprotection. VITAMINS AND HORMONES 2015; 98:487-523. [PMID: 25817878 DOI: 10.1016/bs.vh.2014.12.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Adenosine is an important neuroactive substance in the central nervous system, including in the retina where subclasses of adenosine receptors and transporters are expressed since early stages of development. Here, we review some evidence showing that adenosine plays important functions in the mature as well as in the developing tissue. Adenosine transporters are divided into equilibrative and concentrative, and the major transporter subtype present in the retina is the ENT1. This transporter is responsible for a bidirectional transport of adenosine and the uptake or release of this nucleoside appears to be regulated by different signaling pathways that are also controlled by activation of adenosine receptors. Adenosine receptors are also key players in retina physiology regulating a variety of functions in the mature and developing tissue. Regulation of excitatory neurotransmitter release and neuroprotection are the main functions played be adenosine in the mature tissue, while regulation of cell survival and neurogenesis are some of the functions played by adenosine in developing retina. Since adenosine is neuroprotective against excitotoxic and metabolic dysfunctions observed in neurological and ocular diseases, the search for adenosine-related drugs regulating adenosine transporters and receptors can be important for advancement of therapeutic strategies against these diseases.
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Affiliation(s)
| | - Mariana R Pereira
- Program of Neurosciences, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Rafael Brito
- Program of Neurosciences, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Nádia A de Oliveira
- Program of Neurosciences, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
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7
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Effects of a conventional photocoagulator and a 3-ns pulse laser on preconditioning responses and retinal ganglion cell survival after optic nerve crush. Exp Eye Res 2014; 127:77-90. [DOI: 10.1016/j.exer.2014.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 07/07/2014] [Accepted: 07/10/2014] [Indexed: 11/22/2022]
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8
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Al-Ubaidi MR, Naash MI, Conley SM. A perspective on the role of the extracellular matrix in progressive retinal degenerative disorders. Invest Ophthalmol Vis Sci 2013; 54:8119-24. [PMID: 24346621 DOI: 10.1167/iovs.13-13536] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Progressive inherited retinal degenerative disorders (PIRDDs) are the leading cause of blindness in developed countries, with AMD and RP constituting the majority of PIRDDs. Currently, over 8 million Americans have PIRDDs, and that number is estimated to drastically increase by the end of this decade. Although a mutant protein is expressed starting early during retinal development in patients with PIRDDs, symptoms of retinal degeneration do not manifest until much later. Historically, research has focused on understanding the role a mutation has in the function of a protein and what role the mutant protein has in the disease process. However, it remains unknown why the disease, irrespective of the mutation, manifests clinically much later in life, while cellular indicators of disease (e.g., accumulation of toxic protein products and cell death) occur throughout early and middle life. Herein, we propose that there exists a time point at which the degenerative process is accelerated, leading to the appearance of clinical symptoms. This point is defined by structural disruptions of the extracellular matrix (ECM). Death of a critical number of ECM-maintaining mutant protein-expressing retinal cells contributes to that break point in the degenerative process. Therefore, it is important to understand the changes occurring at the ECM during PIRDDs and to take that into account when therapeutic approaches are designed.
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Affiliation(s)
- Muayyad R Al-Ubaidi
- Department of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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9
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Liu X, Sha O, Cho EYP. Remote ischemic postconditioning promotes the survival of retinal ganglion cells after optic nerve injury. J Mol Neurosci 2013; 51:639-46. [PMID: 23733254 DOI: 10.1007/s12031-013-0036-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 05/20/2013] [Indexed: 02/07/2023]
Abstract
Ischemic conditioning, the application of a mild ischemic stimulus to an ischemia-sensitive structure like the heart or brain either before (preconditioning) or after (postconditioning) its exposure to a lethal ischemic insult, is known to switch on endogenous protective mechanisms. However, most studies of its neuroprotective effect in the central nervous system (CNS) have focused on ischemic damage or related conditions like hypoxia, while its potential in treating other neural diseases remains uncertain. In particular, the recent discovery of remote ischemic postconditioning whereby mild ischemia applied to a region remote from the target after the main ischemic insult also confers protection offers an attractive paradigm to study its potential in other types of neural injury. Retinal ganglion cells damaged by optic nerve transection undergo extensive cell death. However, application of a series of mild ischemic/reperfusion cycles to the hind limb (limb remote ischemic postconditioning) at 10 min or 6 h after optic nerve cut was found to promote ganglion cell survival at 7 days post-injury, with the 10 min postconditioning still exerting protection at 14 days post-injury. Concomitant with the increased ganglion cell survival, 51 % more ganglion cells expressed the small heat shock protein HSP27, when remote ischemic postconditioning was performed at 10 min post-injury, as compared to the sham conditioning group. Our results highlight the potential of using remote ischemic postconditioning as a noninvasive neuroprotective strategy in different CNS disorders like spinal cord and traumatic brain injury.
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Affiliation(s)
- Xia Liu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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10
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Tang J, Du Y, Lee CA, Talahalli R, Eells JT, Kern TS. Low-intensity far-red light inhibits early lesions that contribute to diabetic retinopathy: in vivo and in vitro. Invest Ophthalmol Vis Sci 2013; 54:3681-90. [PMID: 23557732 DOI: 10.1167/iovs.12-11018] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
PURPOSE Treatment with light in the far-red to near-infrared region of the spectrum (photobiomodulation [PBM]) has beneficial effects in tissue injury. We investigated the therapeutic efficacy of 670-nm PBM in rodent and cultured cell models of diabetic retinopathy. METHODS Studies were conducted in streptozotocin-induced diabetic rats and in cultured retinal cells. Diabetes-induced retinal abnormalities were assessed functionally, biochemically, and histologically in vivo and in vitro. RESULTS We observed beneficial effects of PBM on the neural and vascular elements of retina. Daily 670-nm PBM treatment (6 J/cm(2)) resulted in significant inhibition in the diabetes-induced death of retinal ganglion cells, as well as a 50% improvement of the ERG amplitude (photopic b wave responses) (both P < 0.01). To explore the mechanism for these beneficial effects, we examined physiologic and molecular changes related to cell survival, oxidative stress, and inflammation. PBM did not alter cytochrome oxidase activity in the retina or in cultured retinal cells. PBM inhibited diabetes-induced superoxide production and preserved MnSOD expression in vivo. Diabetes significantly increased both leukostasis and expression of ICAM-1, and PBM essentially prevented both of these abnormalities. In cultured retinal cells, 30-mM glucose exposure increased superoxide production, inflammatory biomarker expression, and cell death. PBM inhibited all of these abnormalities. CONCLUSIONS PBM ameliorated lesions of diabetic retinopathy in vivo and reduced oxidative stress and cell death in vitro. PBM has been documented to have minimal risk. PBM is noninvasive, inexpensive, and easy to administer. We conclude that PBM is a simple adjunct therapy to attenuate the development of diabetic retinopathy.
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Affiliation(s)
- Johnny Tang
- Case Western Reserve University, Cleveland, OH 44106, USA
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11
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Salido EM, Dorfman D, Bordone M, Chianelli M, González Fleitas MF, Rosenstein RE. Global and ocular hypothermic preconditioning protect the rat retina from ischemic damage. PLoS One 2013; 8:e61656. [PMID: 23626711 PMCID: PMC3633982 DOI: 10.1371/journal.pone.0061656] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 03/12/2013] [Indexed: 11/18/2022] Open
Abstract
Retinal ischemia could provoke blindness. At present, there is no effective treatment against retinal ischemic damage. Strong evidence supports that glutamate is implicated in retinal ischemic damage. We investigated whether a brief period of global or ocular hypothermia applied 24 h before ischemia (i.e. hypothermic preconditioning, HPC) protects the retina from ischemia/reperfusion damage, and the involvement of glutamate in the retinal protection induced by HPC. For this purpose, ischemia was induced by increasing intraocular pressure to 120 mm Hg for 40 min. One day before ischemia, animals were submitted to global or ocular hypothermia (33°C and 32°C for 20 min, respectively) and fourteen days after ischemia, animals were subjected to electroretinography and histological analysis. Global or ocular HPC afforded significant functional (electroretinographic) protection in eyes exposed to ischemia/reperfusion injury. A marked alteration of the retinal structure and a decrease in retinal ganglion cell number were observed in ischemic retinas, whereas global or ocular HPC significantly preserved retinal structure and ganglion cell count. Three days after ischemia, a significant decrease in retinal glutamate uptake and glutamine synthetase activity was observed, whereas ocular HPC prevented the effect of ischemia on these parameters. The intravitreal injection of supraphysiological levels of glutamate induced alterations in retinal function and histology which were significantly prevented by ocular HPC. These results support that global or ocular HPC significantly protected retinal function and histology from ischemia/reperfusion injury, probably through a glutamate-dependent mechanism.
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Affiliation(s)
- Ezequiel M Salido
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine, University of Buenos Aires/CEFyBO, CONICET, Buenos Aires, Argentina
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12
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Affiliation(s)
- Jerry G. Webb
- Department of Cell and Molecular Pharmacology, Medical University of South Carolina, Charleston, South Carolina
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13
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Caprara C, Grimm C. From oxygen to erythropoietin: relevance of hypoxia for retinal development, health and disease. Prog Retin Eye Res 2011; 31:89-119. [PMID: 22108059 DOI: 10.1016/j.preteyeres.2011.11.003] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 11/01/2011] [Accepted: 11/07/2011] [Indexed: 12/20/2022]
Abstract
Photoreceptors and other cells of the retina consume large quantities of energy to efficiently convert light information into a neuronal signal understandable by the brain. The necessary energy is mainly provided by the oxygen-dependent generation of ATP in the numerous mitochondria of retinal cells. To secure the availability of sufficient oxygen for this process, the retina requires constant blood flow through the vasculature of the retina and the choroid. Inefficient supply of oxygen and nutrients, as it may occur in conditions of disturbed hemodynamics or vascular defects, results in tissue ischemia or hypoxia. This has profound consequences on retinal function and cell survival, requiring an adaptational response by cells to cope with the reduced oxygen tension. Central to this response are hypoxia inducible factors, transcription factors that accumulate under hypoxic conditions and drive the expression of a large variety of target genes involved in angiogenesis, cell survival and metabolism. Prominent among these factors are vascular endothelial growth factor and erythropoietin, which may contribute to normal angiogenesis during development, but may also cause neovascularization and vascular leakage under pathologically reduced oxygen levels. Since ischemia and hypoxia may have a role in various retinal diseases such as diabetic retinopathy and retinopathy of prematurity, studying the cellular and molecular response to reduced tissue oxygenation is of high relevance. In addition, the concept of preconditioning with ischemia or hypoxia demonstrates the capacity of the retina to activate endogenous survival mechanisms, which may protect cells against a following noxious insult. Part of these mechanisms is the local production of protective factors such as erythropoietin. Due to its plethora of effects in the retina including neuro- and vaso-protective activities, erythropoietin has gained strong interest as potential therapeutic factor for retinal degenerative diseases.
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Affiliation(s)
- Christian Caprara
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Zurich, Switzerland
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14
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Fernandez DC, Sande PH, Chianelli MS, Aldana Marcos HJ, Rosenstein RE. Induction of ischemic tolerance protects the retina from diabetic retinopathy. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2264-74. [PMID: 21514439 DOI: 10.1016/j.ajpath.2011.01.040] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Revised: 12/11/2010] [Accepted: 01/10/2011] [Indexed: 11/15/2022]
Abstract
Diabetic retinopathy is a leading cause of acquired blindness. Available treatments are not very effective. We investigated the effect of a weekly application of retinal ischemia pulses (ischemic conditioning) on retinal damage induced by experimental diabetes. Diabetes was induced by an intraperitoneal injection of streptozotocin. Retinal ischemia was induced by increasing intraocular pressure to 120 mmHg for 5 minutes; this maneuver started 3 days after streptozotocin injection and was weekly repeated in one eye, whereas the contralateral eye was submitted to a sham procedure. Diabetic retinopathy was evaluated in terms of i) retinal function (electroretinogram and oscillatory potentials), ii) integrity of blood-retinal barrier (by albumin-Evans blue complex leakage and astrocyte glial fibrillary acidic protein IHC), iii) optical and electron microscopy histopathologic studies, and iv) vascular endothelial growth factor levels (using Western blot analysis and IHC). Brief ischemia pulses significantly preserved electroretinogram a- and b-wave and oscillatory potentials, avoided albumin-Evans blue leakage, prevented the decrease in astrocyte glial fibrillary acidic protein levels, reduced the appearance of retinal edemas, and prevented the increase in vascular endothelial growth factor levels induced by experimental diabetes. When the application of ischemia pulses started 6 weeks after diabetes onset, retinal function was significantly preserved. These results indicate that induction of ischemic tolerance could constitute a fertile avenue for the development of new therapeutic strategies for diabetic retinopathy treatment.
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Affiliation(s)
- Diego C Fernandez
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine, University of Buenos Aires, CEFyBO, CONICET, Buenos Aires, Argentina
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15
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Belforte N, Sande PH, de Zavalía N, Fernandez DC, Silberman DM, Chianelli MS, Rosenstein RE. Ischemic tolerance protects the rat retina from glaucomatous damage. PLoS One 2011; 6:e23763. [PMID: 21887313 PMCID: PMC3161053 DOI: 10.1371/journal.pone.0023763] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 07/24/2011] [Indexed: 11/19/2022] Open
Abstract
Glaucoma is a leading cause of acquired blindness which may involve an ischemic-like insult to retinal ganglion cells and optic nerve head. We investigated the effect of a weekly application of brief ischemia pulses (ischemic conditioning) on the rat retinal damage induced by experimental glaucoma. Glaucoma was induced by weekly injections of chondroitin sulfate (CS) in the rat eye anterior chamber. Retinal ischemia was induced by increasing intraocular pressure to 120 mmHg for 5 min; this maneuver started after 6 weekly injections of vehicle or CS and was weekly repeated in one eye, while the contralateral eye was submitted to a sham procedure. Glaucoma was evaluated in terms of: i) intraocular pressure (IOP), ii) retinal function (electroretinogram (ERG)), iii) visual pathway function (visual evoked potentials, (VEPs)) iv) histology of the retina and optic nerve head. Retinal thiobarbituric acid substances levels were assessed as an index of lipid peroxidation. Ischemic conditioning significantly preserved ERG, VEPs, as well as retinal and optic nerve head structure from glaucomatous damage, without changes in IOP. Moreover, ischemia pulses abrogated the increase in lipid peroxidation induced by experimental glaucoma. These results indicate that induction of ischemic tolerance could constitute a fertile avenue for the development of new therapeutic strategies in glaucoma treatment.
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Affiliation(s)
- Nicolás Belforte
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine, University of Buenos Aires/CEFyBO, CONICET, Buenos Aires, Argentina
- Laboratory of Histology, School of Medicine, University of Morón, Pcia de Buenos Aires, Argentina
| | - Pablo H. Sande
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine, University of Buenos Aires/CEFyBO, CONICET, Buenos Aires, Argentina
| | - Nuria de Zavalía
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine, University of Buenos Aires/CEFyBO, CONICET, Buenos Aires, Argentina
| | - Diego C. Fernandez
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine, University of Buenos Aires/CEFyBO, CONICET, Buenos Aires, Argentina
- Laboratory of Histology, School of Medicine, University of Morón, Pcia de Buenos Aires, Argentina
| | - Dafne M. Silberman
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine, University of Buenos Aires/CEFyBO, CONICET, Buenos Aires, Argentina
| | - Mónica S. Chianelli
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine, University of Buenos Aires/CEFyBO, CONICET, Buenos Aires, Argentina
| | - Ruth E. Rosenstein
- Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, Department of Human Biochemistry, School of Medicine, University of Buenos Aires/CEFyBO, CONICET, Buenos Aires, Argentina
- * E-mail:
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Veth KN, Willer JR, Collery RF, Gray MP, Willer GB, Wagner DS, Mullins MC, Udvadia AJ, Smith RS, John SWM, Gregg RG, Link BA. Mutations in zebrafish lrp2 result in adult-onset ocular pathogenesis that models myopia and other risk factors for glaucoma. PLoS Genet 2011; 7:e1001310. [PMID: 21379331 PMCID: PMC3040661 DOI: 10.1371/journal.pgen.1001310] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Accepted: 01/13/2011] [Indexed: 11/18/2022] Open
Abstract
The glaucomas comprise a genetically complex group of retinal neuropathies that typically occur late in life and are characterized by progressive pathology of the optic nerve head and degeneration of retinal ganglion cells. In addition to age and family history, other significant risk factors for glaucoma include elevated intraocular pressure (IOP) and myopia. The complexity of glaucoma has made it difficult to model in animals, but also challenging to identify responsible genes. We have used zebrafish to identify a genetically complex, recessive mutant that shows risk factors for glaucoma including adult onset severe myopia, elevated IOP, and progressive retinal ganglion cell pathology. Positional cloning and analysis of a non-complementing allele indicated that non-sense mutations in low density lipoprotein receptor-related protein 2 (lrp2) underlie the mutant phenotype. Lrp2, previously named Megalin, functions as an endocytic receptor for a wide-variety of bioactive molecules including Sonic hedgehog, Bone morphogenic protein 4, retinol-binding protein, vitamin D-binding protein, and apolipoprotein E, among others. Detailed phenotype analyses indicated that as lrp2 mutant fish age, many individuals—but not all—develop high IOP and severe myopia with obviously enlarged eye globes. This results in retinal stretch and prolonged stress to retinal ganglion cells, which ultimately show signs of pathogenesis. Our studies implicate altered Lrp2-mediated homeostasis as important for myopia and other risk factors for glaucoma in humans and establish a new genetic model for further study of phenotypes associated with this disease. Complex genetic inheritance, including variable penetrance and severity, underlies many common eye diseases. In this study, we present analysis of a zebrafish mutant, bugeye, which shows complex inheritance of multiple ocular phenotypes that are known risk factors for glaucoma, including high myopia, elevated intraocular pressure, and up-regulation of stress-response genes in retinal ganglion cells. Molecular genetic analysis revealed that mutations in low density lipoprotein receptor-related protein 2 (lrp2) underlie the mutant phenotypes. Lrp2 is a large transmembrane protein expressed in epithelia of the eye. It facilitates transport and clearance of multiple secreted bioactive factors through receptor-mediated endocytosis. Glaucoma, a progressive blinding disorder, usually presents in adulthood and is characterized by optic nerve damage followed by ganglion cell death. In bugeye/lrp2 mutants, ganglion cell death was significantly elevated, but surprisingly moderate, and therefore they do not model this endpoint of glaucoma. As such, bugeye/lrp2 mutants should be considered valuable as a genetic model (A) for buphthalmia, myopia, and regulated eye growth; (B) for identifying genes and pathways that modify the observed ocular phenotypes; and (C) for studying the initiation of retinal ganglion cell pathology in the context of high myopia and elevated intraocular pressure.
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Affiliation(s)
- Kerry N. Veth
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Jason R. Willer
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky, United States of America
| | - Ross F. Collery
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Matthew P. Gray
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Gregory B. Willer
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky, United States of America
| | - Daniel S. Wagner
- Department of Biochemistry and Cell Biology, Rice University, Houston, Texas, United States of America
| | - Mary C. Mullins
- Department of Cell and Developmental Biology, University of Pennsylvania Medical School, Philadelphia, Pennsylvania, United States of America
| | - Ava J. Udvadia
- Department of Biological Sciences, University of Wisconsin–Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Richard S. Smith
- Howard Hughes Medical Institute, The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Simon W. M. John
- Howard Hughes Medical Institute, The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Ronald G. Gregg
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky, United States of America
| | - Brian A. Link
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- * E-mail:
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Peng PH, Chao HM, Juan SH, Chen CF, Liu JH, Ko ML. Pharmacological preconditioning by low dose cobalt protoporphyrin induces heme oxygenase-1 overexpression and alleviates retinal ischemia-reperfusion injury in rats. Curr Eye Res 2011; 36:238-46. [PMID: 21275512 DOI: 10.3109/02713683.2010.539760] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
PURPOSE Retinal ischemia-induced neuronal death plays a crucial role in certain severe visual impairment diseases. The aims of this study were to investigate the effects of low dose cobalt protoporphyrin IX (CoPP), an inducer of heme oxygenase-1 (HO-1), on the retina of rats against ischemia-reperfusion (IR) injury. METHODS Retinal IR was achieved in rats by raising intraocular pressure for 60 min. CoPP (1 mg/ kg) was injected intraperitoneally 24 hr before IR. Retinal injury was assessed by the number of retinal ganglion cells (RGCs) seven days after reperfusion. TUNEL assay was used to detect the appearance of apoptotic cells 24 hr after reperfusion. The expressions of the HO-1 and Bax proteins were evaluated by Western blot. RESULTS Both HO-1 expression, examined by Western blot, and enzyme activity were increased strongly after CoPP administration. Rats treated with CoPP before IR had more RGCs (p = 0.034) and less apoptotic cells (p = 0.04) together with downregulated Bax protein levels (p = 0.03) compared to ischemic rats without CoPP. The protective effects of CoPP were HO-1 dependent because the upregulation of HO-1 and the RGC protection were both abolished by the HO-1 inhibitor tin protoporphyrin (SnPP). CONCLUSIONS In this study, we demonstrated that induction of HO-1 expression by low dose CoPP ameliorated retinal damage from IR injury. The favorable effect appears to be related with modulations of the apoptotic pathway.
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Affiliation(s)
- Pai-Huei Peng
- Department of Ophthalmology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
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Szabadfi K, Mester L, Reglodi D, Kiss P, Babai N, Racz B, Kovacs K, Szabo A, Tamas A, Gabriel R, Atlasz T. Novel neuroprotective strategies in ischemic retinal lesions. Int J Mol Sci 2010; 11:544-561. [PMID: 20386654 PMCID: PMC2852854 DOI: 10.3390/ijms11020544] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 01/27/2010] [Accepted: 01/27/2010] [Indexed: 02/04/2023] Open
Abstract
Retinal ischemia can be effectively modeled by permanent bilateral common carotid artery occlusion, which leads to chronic hypoperfusion-induced degeneration in the entire rat retina. The complex pathways leading to retinal cell death offer a complex approach of neuroprotective strategies. In the present review we summarize recent findings with different neuroprotective candidate molecules. We describe the protective effects of intravitreal treatment with: (i) urocortin 2; (ii) a mitochondrial ATP-sensitive K+ channel opener, diazoxide; (iii) a neurotrophic factor, pituitary adenylate cyclase activating polypeptide; and (iv) a novel poly(ADP-ribose) polymerase inhibitor (HO3089). The retinoprotective effects are demonstrated with morphological description and effects on apoptotic pathways using molecular biological techniques.
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Affiliation(s)
- Krisztina Szabadfi
- Department of Experimental Zoology and Neurobiology, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(K.S.);
(N.B.);
(R.G.)
| | - Laszlo Mester
- Department of Biochemistry and Medical Chemistry, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(L.M.);
(B.R.);
(K.K.);
(A.S.)
| | - Dora Reglodi
- Department of Anatomy, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(D.R.);
(P.K.);
(A.T.)
| | - Peter Kiss
- Department of Anatomy, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(D.R.);
(P.K.);
(A.T.)
| | - Norbert Babai
- Department of Experimental Zoology and Neurobiology, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(K.S.);
(N.B.);
(R.G.)
| | - Boglarka Racz
- Department of Biochemistry and Medical Chemistry, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(L.M.);
(B.R.);
(K.K.);
(A.S.)
| | - Krisztina Kovacs
- Department of Biochemistry and Medical Chemistry, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(L.M.);
(B.R.);
(K.K.);
(A.S.)
| | - Aliz Szabo
- Department of Biochemistry and Medical Chemistry, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(L.M.);
(B.R.);
(K.K.);
(A.S.)
| | - Andrea Tamas
- Department of Anatomy, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(D.R.);
(P.K.);
(A.T.)
| | - Robert Gabriel
- Department of Experimental Zoology and Neurobiology, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(K.S.);
(N.B.);
(R.G.)
| | - Tamas Atlasz
- Department of Experimental Zoology and Neurobiology, University of Pecs, H-7624 Pecs, Hungary; E-Mails:
(K.S.);
(N.B.);
(R.G.)
- Department of Sportbiology, University of Pecs, H-7624 Pecs, Hungary
- Author to whom correspondence should be addressed; E-Mail:
; Tel.: +36-72-503-600/4613; Fax: +36-72-501-517
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Stella SL, Hu WD, Brecha NC. Adenosine suppresses exocytosis from cone terminals of the salamander retina. Neuroreport 2009; 20:923-9. [PMID: 19491713 DOI: 10.1097/wnr.0b013e32832ca4b0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In the retina, adenosine is released in the dark and has been shown to inhibit Ca2+ influx through voltage-gated Ca2+ channels in cones. Therefore, we tested whether adenosine can inhibit exocytosis from isolated cone photoreceptors. Simultaneous measurements of membrane exocytosis and Ca2+ were made from cones using the activity-dependent dye, Synaptored-C2, and the Ca2+ indicator dye, Fluo-4. Adenosine suppressed exocytosis in cones, indicating that transmitter release is also reduced from cone terminals, and further supports an inhibitory mechanism for modulating transmitter release onto second-order neurons. Furthermore, this raises the possibility that adenosine might be neuroprotective for photoreceptors and second-order neurons by suppressing Ca2+ levels in cones and reducing exocytosis of L-glutamate, respectively.
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Affiliation(s)
- Salvatore L Stella
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California 90095-1763, USA.
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Fernandez DC, Chianelli MS, Rosenstein RE. Involvement of glutamate in retinal protection against ischemia/reperfusion damage induced by post-conditioning. J Neurochem 2009; 111:488-98. [PMID: 19682205 DOI: 10.1111/j.1471-4159.2009.06334.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Retinal ischemia could provoke blindness and there is no effective treatment against retinal ischemic damage. Brief intermittent ischemia applied during the onset of reperfusion (i.e., post-conditioning) protects the retina from ischemia/reperfusion injury. Multiple evidences support that glutamate is implicated in retinal ischemic damage. We investigated the involvement of glutamate clearance in post-conditioning-induced protection. For this purpose, ischemia was induced by increasing intra-ocular pressure for 40 min, and 5 min after reperfusion, animals underwent seven cycles of 1 min/1 min ischemia/reperfusion. One, three, or seven days after ischemia, animals were subjected to electroretinography and histological analysis. The functional and histological protection induced by post-conditioning was evident at 7 (but not 1 or 3) days post-ischemia. An increase in Müller cell glial fibrillary acidic protein (GFAP) levels was observed at 1, 3, and 7 days after ischemia, whereas post-conditioning reduced GFAP levels of Müller cells at 3 and 7 days post-ischemia. Three days after ischemia, a significant decrease in glutamate uptake and glutamine synthetase activity was observed, whereas post-conditioning reversed the effect of ischemia. The intravitreal injection of supraphysiological levels of glutamate mimicked electroretinographic and histological alterations provoked by ischemia, which were abrogated by post-conditioning. These results support the involvement of glutamate in retinal protection against ischemia/reperfusion damage induced by post-conditioning.
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Affiliation(s)
- Diego C Fernandez
- Department of Human Biochemistry, Laboratory of Retinal Neurochemistry and Experimental Ophthalmology, School of Medicine, University of Buenos Aires/CEFyBO, CONICET, Buenos Aires, Argentina
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Zhu Y, Zhang L, Gidday JM. Deferroxamine preconditioning promotes long-lasting retinal ischemic tolerance. J Ocul Pharmacol Ther 2009; 24:527-35. [PMID: 19046123 DOI: 10.1089/jop.2008.0082] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
OBJECTIVE "Ischemic tolerance" can be induced in the retina by "preconditioning" with brief periods of non-injurious retinal ischemia or systemic hypoxia. The present study was undertaken to assess whether tolerance can be induced pharmacologically by deferroxamine (DFX), an iron chelator, which promotes the expression of the transcription factor, hypoxia-inducible factor 1-alpha (HIF-1alpha), and to identify potential HIF-1alpha -induced effectors of this endogenous protective response. METHODS ND4 Swiss-Webster mice were preconditioned with DFX (200 mg/kg, intraperitoneally) as a single dose (SDP) or as repetitive doses (RDP; 6 doses over 2 weeks) and then subjected to 30 min of retinal ischemia (by intraocular pressure elevation) 1 or 4 weeks later. Retinal layer thicknesses and cell counts were quantified 1 week after ischemia. Retinae of additional mice were obtained at various times after SDP or RDP to examine protein-level expression of HIF-1alpha and adrenomedullin (ADM), a HIF-1alpha gene target, by immunoblotting and immunohistochemistry. RESULTS Ischemia-induced injury was significantly attenuated by SDP 1 week earlier, but not when SDP occurred 4 weeks earlier. However, RDP performed 4 weeks earlier was potently neuroprotective. DFX robustly induced HIF-1alpha protein expression throughout the inner retina, and levels of HIF-1alpha protein remained significantly elevated over the 1- and 4-week periods of time between the respective SDP and RDP stimulus and the induction of retinal ischemia. Increases in ADM protein expression were evident throughout the retina following both preconditioning treatments. CONCLUSIONS DFX preconditions the retina against ischemic injury and multiple doses promote a long-lasting, ischemia-protective phenotype. The widespread and protracted elevations in HIF-1alpha protein levels and the robust expression of one of its neuroprotective, prosurvival gene targets, ADM, strongly suggest that DFX-induced preconditioning is HIF-1alpha-dependent. The ability to pharmacologically induce ischemic tolerance in the retina by a clinically well-tolerated drug underscores the potential therapeutic utility of preconditioning for retinal protection in various ischemic retinopathies.
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Affiliation(s)
- Yanli Zhu
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO 63110, USA
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Ding J, Ding N, Wang N, Lu Q, Lu N, Yang D, Bu X, Han S, Li J. Determination of conventional protein kinase C isoforms involved in high intraocular pressure-induced retinal ischemic preconditioning of rats. Vision Res 2008; 49:315-21. [PMID: 19013479 DOI: 10.1016/j.visres.2008.10.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 10/13/2008] [Accepted: 10/13/2008] [Indexed: 01/26/2023]
Abstract
Evidence indicates that conventional protein kinase C (cPKC) plays a pivotal role in the development of retinal ischemic preconditioning (IPC). In this study, the effect of high intraocular pressure (IOP)-induced retinal IPC on cPKC isoform-specific membrane translocation and protein expression were observed. We found that cPKCgamma membrane translocation increased significantly at the early stage (20min-1h), while the protein expression levels of cPKCalpha and gamma were markedly elevated in the delayed retinal IPC (12-168h) of rats. The increased protein expressions of cPKCalpha at 72h and cPKCgamma at 24h after IPC were further confirmed by immunofluorescence staining. In addition, we found that cPKCgamma co-localized with retinal ganglion cell (RGC)-specific marker, neurofilaments heavy chain (NF-H) by using double immunofluorescence labeling. These results suggest that increased cPKCgamma membrane translocation and up-regulated protein expressions of cPKCalpha and gamma are involved in the development of high IOP-induced rat retinal IPC.
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Affiliation(s)
- Jingwen Ding
- Beijing Tongren Eye Center, Capital Medical University Affiliated Beijing Tongren Hospital, Vision Science Laboratory, School of Ophthalmology, Beijing, China
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Husain S, Potter DE. The opioidergic system: potential roles and therapeutic indications in the eye. J Ocul Pharmacol Ther 2008; 24:117-40. [PMID: 18355128 DOI: 10.1089/jop.2007.0112] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Shahid Husain
- Department of Ophthalmology, Storm Eye Institute, Hewitt Laboratory of the Ola B Williams Glaucoma Center, Medical University of South Carolina, Charleston, SC 29425, USA.
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Morphine pretreatment provides histologic protection against ischemia-reperfusion injury in rabbit retina. Retina 2008; 28:511-7. [PMID: 18327147 DOI: 10.1097/iae.0b013e31815960c3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
PURPOSE Pharmacologic preconditioning with morphine has been shown to protect several kinds of tissues against ischemia-reperfusion injury. The aim of the present study was to investigate whether intravitreal administration of morphine induces structural protection against ischemic damage in a rabbit model of ischemic retinopathy. METHODS Twenty-eight male white New Zealand rabbits were used. Animals in saline control group received 0.1 mL of phosphate-buffered saline (PBS) intravitreally with no postinjection ischemia. In the saline-control ischemia group, 15 minutes after injection of PBS, retinal ischemia was induced by raising intraocular pressure to 150 mmHg for 60 minutes. In three treatment-ischemia groups, morphine (1, 5, and 10 micromol/L) was administered intravitreally 15 minutes before induction of ischemia. In another experiment, naloxone (40 micromol/L) was administered 5 minutes before intravitreal administration of morphine (10 micromol/L) followed by 60 minutes of ischemia to investigate the role of opioid receptors in mediating the possible protective effect of morphine. Toxicity controls were performed with morphine (10 micromol/L) and naloxone (40 micromol/L) without ischemia. Histologic evaluation was performed for all groups on the seventh postoperative day. RESULTS Sixty minutes of ischemia led to severe cell loss in ganglion cell layer and thinning of the inner nuclear layer in saline-control ischemia compared to that of the nonischemia control group (P < 0.001). Thickness of the inner plexiform layer to the inner limiting membrane was significantly increased due to edema (P < 0.001). Administration of morphine in higher doses (5 and 10 micromol/L) significantly improved all of the above mentioned indices (P < 0.05). Administration of naloxone 15 minutes before morphine reversed most of the morphine protective effects. CONCLUSIONS Morphine pretreatment provides significant histologic protection against ischemic injury in rabbit retina. Pharmacologic evidence suggests that this protective phenomenon may be mediated in part by opiate receptors.
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Crooke A, Guzmán-Aranguez A, Peral A, Abdurrahman MKA, Pintor J. Nucleotides in ocular secretions: their role in ocular physiology. Pharmacol Ther 2008; 119:55-73. [PMID: 18562011 DOI: 10.1016/j.pharmthera.2008.04.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Accepted: 04/28/2008] [Indexed: 12/15/2022]
Abstract
The eye is the sense organ that permits the detection of light owing to the existence of a sophisticated neuronal array, called the retina, which is responsive to photons. The correct functioning of this complex system requires the coordination of several intraocular structures that ultimately permit the perfect focusing of images on the neural retina. Light has to pass through different media: the tear, the cornea, aqueous humour, lens, and vitreous humour before it reaches the retina. Moreover, the composition and structure of some of these media can change due to several physiological mechanisms. Nucleotides are active components of the humours bathing relevant ocular structures. The tear contains nucleotides and dinucleotides that control the process of tearing, wound healing and protects of superficial infections. In the inner eye, the aqueous humour also presents a collection of mono and dinucleotides that affect pupil contraction, aqueous humour production and accommodation. Behind the lens and between this structure and the retina the vitreous humour can modify the physiology of the retinal cells, mostly the ganglion cells. By investigating the actions of nucleotides and dinucleotide present in the ocular humours we will be able not only to understand the functioning of the ocular structures but also to develop new pharmacological therapies for pathologies such as dry eye, glaucoma or retinal detachment.
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Affiliation(s)
- Almudena Crooke
- Departamento de Bioquímica, E.U. Optica, Universidad Complutense de Madrid, 28037 Madrid, Spain
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Obolensky A, Berenshtein E, Konijn AM, Banin E, Chevion M. Ischemic preconditioning of the rat retina: protective role of ferritin. Free Radic Biol Med 2008; 44:1286-94. [PMID: 18082149 DOI: 10.1016/j.freeradbiomed.2007.10.060] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2007] [Revised: 10/29/2007] [Accepted: 10/30/2007] [Indexed: 01/21/2023]
Abstract
Ischemic preconditioning (IPC) of the retina, accomplished by ischemia of short duration, is highly effective in preventing subsequent severe injury caused by iron-dependent free radical burst after prolonged ischemia. To investigate the mechanistic basis for IPC rescue, we examined changes in the levels of the retinal redox-active and labile iron pool, ferritin, and ferritin-bound iron. Prolonged ischemia severely impaired retinal function, with total loss of the full-field electroretinographic response. IPC provided marked protection against such injury. Histological examination revealed that ischemia-associated structural damage and loss of cells in the outer and inner nuclear layers were largely prevented by IPC. Ferritin levels decreased after prolonged ischemia but remained close to normal when the ischemic episode was preceded by IPC. The protective effect of IPC on retinal function and ferritin was blocked by a zinc-desferrioxamine complex known to interfere with iron signaling. The results suggest a mechanism whereby IPC activates an iron signaling pathway leading to a marked increase in ferritin levels, which mediates resistance to prolonged ischemia.
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Affiliation(s)
- Alexey Obolensky
- Department of Ophthalmology, The Hebrew University-Hadassah Schools of Medicine and Dental Medicine, Jerusalem 91120, Israel
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Berkowitz BA, Gradianu M, Schafer S, Jin Y, Porchia A, Iezzi R, Roberts R. Ionic dysregulatory phenotyping of pathologic retinal thinning with manganese-enhanced MRI. Invest Ophthalmol Vis Sci 2008; 49:3178-84. [PMID: 18362105 DOI: 10.1167/iovs.08-1720] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To test the hypothesis that manganese-enhanced MRI (MEMRI) provides a sensitive and robust measure of an important retinal ionic dysregulatory phenotype in pathologic retinal thinning. METHODS Four hours after intraperitoneal MnCl(2) injection, high-resolution MEMRI data were collected from overnight dark-adapted male control Sprague-Dawley and albino Royal College of Surgeons rats before (at development stage postnatal day [P] 17) and during photoreceptor degeneration (P36 and P57). In separate experiments, control rats, with and without repetitive hypoxic preconditioning, were subjected to high IOP (100 mm Hg) for 60 minutes followed by 24 hours or 7 days of reperfusion (e.g., ischemia/reperfusion). Central retinal thickness and intraretinal ion activity were measured from the MEMRI data. Histology examination was also performed to confirm retinal damage. RESULTS In two different neurodegenerative models, MEMRI revealed first-time evidence for changes (P < 0.05) in intraretinal ion regulation before and during pathologic, but not (P > 0.05) developmental, retinal thinning. This phenotype was significantly altered by a neuroprotective repetitive hypoxic preconditioning protocol. CONCLUSIONS MEMRI and a nontoxic systemic dose of MnCl(2) provided an objective, noninvasive measure of an ionic deregulatory phenotype that appears useful for improved early diagnosis and treatment prognosis in a range of neurodegenerative diseases and their treatment.
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Affiliation(s)
- Bruce A Berkowitz
- Department of Anatomy and Cell Biology, Wayne State University, Detroit, Michigan 48201, USA.
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Riva CE, Schmetterer L. Microcirculation of the Ocular Fundus. Microcirculation 2008. [DOI: 10.1016/b978-0-12-374530-9.00018-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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Levkovitch-Verbin H, Harizman N, Dardik R, Nisgav Y, Vander S, Melamed S. Regulation of cell death and survival pathways in experimental glaucoma. Exp Eye Res 2007; 85:250-8. [PMID: 17586494 DOI: 10.1016/j.exer.2007.04.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2006] [Revised: 04/20/2007] [Accepted: 04/25/2007] [Indexed: 10/23/2022]
Abstract
This study investigates cell death and survival pathways in experimental glaucoma using the translimbal photocoagulation laser model. Glaucoma was induced unilaterally in 79 Wistar rats and all eyes developed elevated intraocular pressure. The involvement of caspase-3, p-AKT and members of the MAP kinase pathway was evaluated by immunohistochemistry and Western blotting. We found that protein levels of caspase-3 were elevated from day 15 to day 30 (p<0.05). All investigated members of the MAP kinase pathway were significantly activated. P-SAPK/JNK activation began on day 2, reaching a 6-fold elevation by day 30 (p<0.05). The p-P38 level was elevated on days 2 and 8 (p<0.05), followed by a decrease to baseline on day 15. The level of p-ATF-2, the substrate of P38, was significantly elevated at all time points tested, up to day 30 (p<0.05). P-ERK was detected early (p<0.05) on day 1, returning to normal on day 15. The pro-survival protein p-Akt, a member of the PI3-kinase survival pathway, was also detected early on day 1 (p<0.05) returning to baseline on day 8 and remaining unchanged up to 64days. We conclude that retinal ganglion cell death in glaucoma involves activation, at different time points, of multiple pro-apoptotic pathways (the MAP kinase pathway and the caspase family) and pro-survival (PI-3 Kinase/ Akt and p-ERK).
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Affiliation(s)
- Hani Levkovitch-Verbin
- Sam Rothberg Ophthalmic Molecular Biology Laboratory, Goldschleger Eye Institute, Sheba Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Hashomer 52621, Israel.
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31
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Azadi S, Johnson LE, Paquet-Durand F, Perez MTR, Zhang Y, Ekström PAR, van Veen T. CNTF+BDNF treatment and neuroprotective pathways in the rd1 mouse retina. Brain Res 2007; 1129:116-29. [PMID: 17156753 DOI: 10.1016/j.brainres.2006.10.031] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 10/05/2006] [Accepted: 10/06/2006] [Indexed: 11/22/2022]
Abstract
The rd1 mouse is a relevant model for studying the mechanisms of photoreceptor degeneration in retinitis pigmentosa. Treatment with ciliary neurotrophic factor (CNTF) in combination with brain derived neurotrophic factor (BDNF) is known to rescue photoreceptors in cultured rd1 retinal explants. To shed light on the underlying mechanisms, we studied the effects of 9 days (starting at postnatal day 2) in vitro CNTF+BDNF treatment on the endogenous production of CNTF, BDNF, fibroblast growth factor 2 (FGF2), or the activation of extracellular signal-regulated kinase (ERK), Akt and cAMP-response-element-binding protein (CREB) in retinal explants. In rd1 explants, CNTF+BDNF decreased the number of TUNEL-positive photoreceptors. The treatment also increased endogenous rd1 levels of CNTF and BDNF, but lowered the level of FGF2 expression in rd1 explants. When wild-type explants were treated, endogenous CNTF was similarly increased, while BDNF and FGF2 levels remained unaffected. In addition, treatment of rd1 retinas strongly increased the phosphorylation of ERK, Akt and CREB. In treated wild-type explants, the same parameters were either unchanged (ERK) or decreased (Akt and CREB). The results suggest a role for Akt, ERK and CREB in conveying the neuroprotective effect of CNTF+BDNF treatment in rd1 retinal explants.
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Affiliation(s)
- Seifollah Azadi
- Department of Ophthalmology, University of Lund, BMC-B13, SE-221 84 LUND, Sweden
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Sewell RDE, Gruden MA, Pache DM, Storogeva ZI, Kostanyan IA, Proshin AT, Yurasov VV, Sherstnev VV. Does the human leukaemia differentiation factor fragment HLDF6 improve memory via brain DNA and protein synthesis? J Psychopharmacol 2005; 19:602-8. [PMID: 16272181 DOI: 10.1177/0269881105056645] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The novel human differentiating factor peptide fragment HLDF6 (Thr-Gly-Glu-Asn-His-Arg) was synthesized and purified. HLDF6 (0.1mg/kg i.p. but not 1mg/kg i.p.) improved not only long-term (24h) memory in adult rats in the water maze behavioural paradigm but also performance in the delayed matching-to-position (DMTP) task (0.3 and 1.0 but not 0.1mg/kg i.p). Hence, HLDF6 not only enhanced allocentric spatial learning and reference memory (water maze) but also improved temporal, spatial and working memory processes in the DMTP behavioural paradigm. Immunoreactivity blotting analysis of HLDF (the protein precursor of HLDF6) was performed and the following rank order of visual intensities from brain structures was noted: hippocampus cerebral cortex cerebellum hypothalamus striatum. Subsequently, we found that the highest absolute levels of HLDF were expressed in the hippocampus and cerebral cortex as detected by ELISA. We also demonstrated that HLDF6 enhanced [(3)H]-thymidine and [(14)C]-leucine incorporation into whole brain and hippocampal homogenates (maxima occurring within the range 10 (-12)-10 (-6) M) suggesting that this hexapeptide promoted de novo DNA and protein biosynthesis. We discuss this data in terms of their implications for links with other integrative metabolic pathways involving immediate early gene activation which may underpin a potential application for HLDF6 in limiting memory impairments associated with neurodegenerative diseases.
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Affiliation(s)
- Robert D E Sewell
- Welsh School of Pharmacy, Cardiff University, Redwood Building, Cathays Park, King Edward VII Ave, Cardiff CF10 3XF, UK.
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Anderson MG, Libby RT, Gould DB, Smith RS, John SWM. High-dose radiation with bone marrow transfer prevents neurodegeneration in an inherited glaucoma. Proc Natl Acad Sci U S A 2005; 102:4566-71. [PMID: 15758074 PMCID: PMC555465 DOI: 10.1073/pnas.0407357102] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Indexed: 11/18/2022] Open
Abstract
Here, we show that high-dose gamma-irradiation accompanied with syngeneic bone marrow transfer can confer complete protection against glaucoma in a mouse model. Because bone marrow genotype was unaltered by this procedure, it was not the causative agent. The neuroprotection is robust and highly reproducible. Glaucoma-prone DBA/2J mice received a single treatment at 5-8 weeks of age and were protected from glaucomatous retinal ganglion cell degeneration out to 14 months of age (oldest assessed). By 12-14 months, retinal ganglion cell degeneration is usually very severe and essentially complete in the majority of untreated DBA/2J mice. To assess reproducibility, three groups of mice were treated at different times, and the results were essentially the same each time. Considering all experiments, the vast majority of treated mice had no detectable glaucomatous neurodegeneration. A beneficial effect of treatment including high-dose radiation is unprecedented, and we are not aware of any other neuroprotective effects this substantial. Because of the robust protective effect, this treatment offers another tool for studying mechanisms of neuroprotection.
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Linden R, Martins RAP, Silveira MS. Control of programmed cell death by neurotransmitters and neuropeptides in the developing mammalian retina. Prog Retin Eye Res 2004; 24:457-91. [PMID: 15845345 DOI: 10.1016/j.preteyeres.2004.10.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
It has long been known that a barrage of signals from neighboring and connecting cells, as well as components of the extracellular matrix, control cell survival. Given the extensive repertoire of retinal neurotransmitters, neuromodulators and neurotrophic factors, and the exhuberant interconnectivity of retinal interneurons, it is likely that various classes of released neuroactive substances may be involved in the control of sensitivity to retinal cell death. The aim of this article is to review evidence that neurotransmitters and neuropeptides control the sensitivity to programmed cell death in the developing retina. Whereas the best understood mechanism of execution of cell death is that of caspase-mediated apoptosis, current evidence shows that not only there are many parallel pathways to apoptotic cell death, but non-apoptotic programs of execution of cell death are also available, and may be triggered either in isolation or combined with apoptosis. The experimental data show that many upstream signaling pathways can modulate cell death, including those dependent on the second messengers cAMP-PKA, calcium and nitric oxide. Evidence for anterograde neurotrophic control is provided by a variety of models of the central nervous system, and the data reviewed here indicate that an early function of certain neurotransmitters, such as glutamate and dopamine, as well as neuropeptides such as pituitary adenylyl cyclase-activating polypeptide and vasoactive intestinal peptide is the trophic support of cell populations in the developing retina. This may have implications both regarding the mechanisms of retinal organogenesis, as well as pathological conditions leading to retinal dystrophies and to dysfunctional cellular behavior.
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Affiliation(s)
- Rafael Linden
- Centro de Ciencias da Saude, Instituto de Biofísica da UFRJ, Cidade Universitária, bloco G, Rio de Janeiro 21949-900, Brazil.
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