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Nag TC. Müller cell vulnerability in aging human retina: Implications on photoreceptor cell survival. Exp Eye Res 2023; 235:109645. [PMID: 37683797 DOI: 10.1016/j.exer.2023.109645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/29/2023] [Accepted: 09/05/2023] [Indexed: 09/10/2023]
Abstract
Müller glial cells (MC) support various metabolic functions of the retinal neurons, and maintain the homeostasis. Oxidative stress is intensified with aging, and in human retina, MC and photoreceptors undergo lipid peroxidation and protein nitration. Information on how MC respond to oxidative stress is vital to understand the fate of aging retinal neurons. This study examined age-related changes in MC of donor human retina (age: 35-98 years; N = 18 donors). Ultrastructural and immunohistochemical observations indicate that MC undergo gliosis and increased lipid peroxidation, and show osmotic changes with advanced aging (>80 years). Photoreceptor cells also undergo oxidative-nitrosative stress with aging, and their synapses also show clear osmotic swelling. MC respond to oxidative stress via proliferation of smooth endoplasmic reticulum in their processes, and increased expression of aquaporin-4 in endfeet and outer retina. In advanced aged retinas (81-98 years), they showed mitochondrial disorganisation, accumulation of lipids and autophagosomes, lipofuscin granules and axonal remnants in phagolysosomes in their inner processes, suggesting a reduced phagocytotic potential in them with aging. Glutamine synthetase expression does not alter until advanced aging, when the retinas show its increased expression in endfeet and Henle fiber layer. It is evident that MC are vulnerable with normal aging and this could be a reason for photoreceptor cell abnormalities reported with aging of the human retina.
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Affiliation(s)
- Tapas C Nag
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India.
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2
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Khaloo P, Qahremani R, Rabizadeh S, Omidi M, Rajab A, Heidari F, Farahmand G, Bitaraf M, Mirmiranpour H, Esteghamati A, Nakhjavani M. Nitric oxide and TNF-α are correlates of diabetic retinopathy independent of hs-CRP and HbA1c. Endocrine 2020; 69:536-541. [PMID: 32494901 DOI: 10.1007/s12020-020-02353-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 05/15/2020] [Indexed: 12/20/2022]
Abstract
PURPOSE Regarding the role of inflammation in progression of diabetes this study was conducted to investigate the association between inflammatory biomarkers such as nitric oxide (NO), tumor necrosis factor alpha (TNF-α), and high-sensitivity C-reactive protein (hs-CRP) with the chance of existence of diabetic retinopathy and its progression in patients with diabetes. METHODS A total of 83 patients with T2DM (Type 2 diabetes mellitus) were divided into three groups of patients with proliferative diabetic retinopathy (PDR), patients with non-proliferative diabetic retinopathy (NPDR) and patients without diabetic retinopathy (NDR) based on ophthalmologic funduscopic examination. Twenty six healthy controls were also enrolled. Blood samples were taken after 12 h of overnight fasting, NO, TNF-α, and hs-CRP were measured. Association of the level of these biomarkers with retinopathy was analyzed. RESULTS The levels of TNF-α, NO and hs-CRP were higher among patients with diabetic retinopathy. Multinomial Logistic Regression model showed that TNF-α and NO could predict the presence of retinopathy among patients with diabetes when adjusted for hs-CRP, HbA1c, FBS, gender, total cholesterol, triglyceride, HDL, LDL, BMI, and age (respectively OR = 1.76, CI 95% = 1.01-3.02, p = 0.046 and OR = 1.12, CI 95% = 1.05-1.18, p < 0.001); however they could not predict the severity of retinopathy. In ROC analysis AUC for TNFα was 0.849 (p < 0.001) and for NO was 0.907 (p < 0.001). Serum TNF-α level of 7.10 pmol/L could be suggestive of the presence of retinopathy (sensitivity = 92.2% and specificity = 66.0%), also serum NO level of 45.96 μmol/L could be suggestive of the presence of retinopathy (sensitivity = 96.1% and specificity = 86%). CONCLUSIONS Our results suggest elevated levels of NO and TNF-α can be suggestive of diabetic retinopathy.
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Affiliation(s)
- Pegah Khaloo
- Endocrinology and Metabolism Research Center (EMRC), Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Reihane Qahremani
- Endocrinology and Metabolism Research Center (EMRC), Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Soghra Rabizadeh
- Endocrinology and Metabolism Research Center (EMRC), Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Omidi
- Endocrinology and Metabolism Research Center (EMRC), Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Armin Rajab
- Endocrinology and Metabolism Research Center (EMRC), Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Firouzeh Heidari
- Endocrinology and Metabolism Research Center (EMRC), Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ghasem Farahmand
- Endocrinology and Metabolism Research Center (EMRC), Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoume Bitaraf
- Endocrinology and Metabolism Research Center (EMRC), Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Hossein Mirmiranpour
- Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Alireza Esteghamati
- Endocrinology and Metabolism Research Center (EMRC), Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Manouchehr Nakhjavani
- Endocrinology and Metabolism Research Center (EMRC), Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran.
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Wright WS, Eshaq RS, Lee M, Kaur G, Harris NR. Retinal Physiology and Circulation: Effect of Diabetes. Compr Physiol 2020; 10:933-974. [PMID: 32941691 PMCID: PMC10088460 DOI: 10.1002/cphy.c190021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
In this article, we present a discussion of diabetes and its complications, including the macrovascular and microvascular effects, with the latter of consequence to the retina. We will discuss the anatomy and physiology of the retina, including aspects of metabolism and mechanisms of oxygenation, with the latter accomplished via a combination of the retinal and choroidal blood circulations. Both of these vasculatures are altered in diabetes, with the retinal circulation intimately involved in the pathology of diabetic retinopathy. The later stages of diabetic retinopathy involve poorly controlled angiogenesis that is of great concern, but in our discussion, we will focus more on several alterations in the retinal circulation occurring earlier in the progression of disease, including reductions in blood flow and a possible redistribution of perfusion that may leave some areas of the retina ischemic and hypoxic. Finally, we include in this article a more recent area of investigation regarding the diabetic retinal vasculature, that is, the alterations to the endothelial surface layer that normally plays a vital role in maintaining physiological functions. © 2020 American Physiological Society. Compr Physiol 10:933-974, 2020.
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Affiliation(s)
- William S Wright
- Department of Biomedical Sciences, University of South Carolina School of Medicine Greenville, Greenville, South Carolina, USA
| | - Randa S Eshaq
- Department of Molecular and Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, USA
| | - Minsup Lee
- Department of Molecular and Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, USA
| | - Gaganpreet Kaur
- Department of Molecular and Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, USA
| | - Norman R Harris
- Department of Molecular and Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, USA
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Cantó A, Olivar T, Romero FJ, Miranda M. Nitrosative Stress in Retinal Pathologies: Review. Antioxidants (Basel) 2019; 8:antiox8110543. [PMID: 31717957 PMCID: PMC6912788 DOI: 10.3390/antiox8110543] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 10/30/2019] [Accepted: 11/06/2019] [Indexed: 12/20/2022] Open
Abstract
Nitric oxide (NO) is a gas molecule with diverse physiological and cellular functions. In the eye, NO is used to maintain normal visual function as it is involved in photoreceptor light transduction. In addition, NO acts as a rapid vascular endothelial relaxant, is involved in the control of retinal blood flow under basal conditions and mediates the vasodilator responses of different substances such as acetylcholine, bradykinin, histamine, substance P or insulin. However, the retina is rich in polyunsaturated lipid membranes and is sensitive to the action of reactive oxygen and nitrogen species. Products generated from NO (i.e., dinitrogen trioxide (N2O3) and peroxynitrite) have great oxidative damaging effects. Oxygen and nitrogen species can react with biomolecules (lipids, proteins and DNA), potentially leading to cell death, and this is particularly important in the retina. This review focuses on the role of NO in several ocular diseases, including diabetic retinopathy, retinitis pigmentosa, glaucoma or age-related macular degeneration (AMD).
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Affiliation(s)
- Antolin Cantó
- Departamento Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Cardenal Herrera-CEU, CEU Universities, 64315 Valencia, Spain; (A.C.); (T.O.)
| | - Teresa Olivar
- Departamento Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Cardenal Herrera-CEU, CEU Universities, 64315 Valencia, Spain; (A.C.); (T.O.)
| | - Francisco Javier Romero
- Departamento de Ciencias Biomédicas, Universidad Europea de Valencia, 46010 Valencia, Spain;
| | - María Miranda
- Departamento Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Cardenal Herrera-CEU, CEU Universities, 64315 Valencia, Spain; (A.C.); (T.O.)
- Correspondence: ; Tel.: +34-961369000
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Nag TC, Maurya M, Roy TS. Age-related changes of the human retinal vessels: Possible involvement of lipid peroxidation. Ann Anat 2019; 226:35-47. [PMID: 31330304 DOI: 10.1016/j.aanat.2019.06.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 06/28/2019] [Accepted: 06/29/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND Aging of the human retina is accompanied by oxidative stress that exerts profound changes in the retinal neurons. It is unknown if oxidative stress influences the cellular components of the retinal vessels in some ways. METHODS We examined changes in retinal vessels in human donor eyes (age: 35-94 years; N=18) by light and transmission electron microscopy, TUNEL and immunohistochemistry for biomarkers of vascular smooth muscle cells (SMC; actin), oxidative stress (4-hydroxy 2-nonenal [HNE] and nitrotyrosine), microglia (Iba-1) and vessels (isolectin B4). RESULTS The earliest changes in the endothelium and pericytes of capillaries are apparent from the seventh decade. With aging, there is clear loss of organelles and cytoplasmic filaments, and a progressive thickening of the endothelial and pericyte basal lamina. Loss of filaments, accumulation of lipofuscin and autophagic vacuoles are significant events in aging pericytes and SMC. Actin immunolabelling reveals discontinuity in arterial SMC layers during eighth decade, indicating partial degeneration of SMC. This is followed by hyalinization, with degeneration of the endothelium and SMC in arteries and arterioles of the nerve fibre layer (NFL) and ganglion cell layer in ninth decade. Iba-1 positive microglia were in close contact with the damaged vessels in inner retina, and their cytoplasm was rich in lysosomes. HNE immunoreactivity, but not of nitrotyrosine, was detected in aged vessels from seventh decade onwards, suggesting that lipid peroxidation is a major problem of aged vessels. However, TUNEL positivity seen during this period was limited to few arteries and venules of NFL. CONCLUSION This study shows prominent age-related alterations of the pericytes and SMC of retinal vessels. These changes may limit the energy supply to the neurons and be responsible for age-related loss of neurons of the inner retina.
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Affiliation(s)
- Tapas Chandra Nag
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India.
| | - Meenakshi Maurya
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Tara Sankar Roy
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India
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Mohammad HMF, Sami MM, Makary S, Toraih EA, Mohamed AO, El-Ghaiesh SH. Neuroprotective effect of levetiracetam in mouse diabetic retinopathy: Effect on glucose transporter-1 and GAP43 expression. Life Sci 2019; 232:116588. [PMID: 31226418 DOI: 10.1016/j.lfs.2019.116588] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 06/14/2019] [Accepted: 06/17/2019] [Indexed: 01/12/2023]
Abstract
AIMS Retinopathy is a neurodegenerative complication associating diabetes mellitus. Diabetic retinopathy (DR) is the primary reason of visual loss during early adulthood. DR has a complicated multifactorial pathophysiology initiated by hyperglycaemia-induced ischaemic neurodegenerative retinal changes, followed by vision-threatening consequences. The main therapeutic modalities for DR involve invasive delivery of intravitreal antiangiogenic agents as well as surgical interventions. The current work aimed to explore the potential anti-inflammatory and retinal neuroprotective effects of levetiracetam. MAIN METHODS This study was performed on alloxan-induced diabetes in mice (n: 21). After 10 weeks, a group of diabetic animals (n: 7) was treated with levetiracetam (25 mg/kg) for six weeks. Retinal tissues were dissected and paraffin-fixed for examination using (1) morphometric analysis with haematoxylin and eosin (HE), (2) immunohistochemistry (GLUT1, GFAP and GAP43), and (3) RT-PCR-detected expression of retinal inflammatory and apoptotic mediators (TNF-α, IL6, iNOS, NF-κB and Tp53). KEY FINDINGS Diabetic mice developed disorganized and debilitated retinal layers with upregulation of the gliosis marker GFAP and downregulation of the neuronal plasticity marker GAP43. Additionally, diabetic retinae showed increased transcription of NF-κB, TNF-α, IL6, iNOS and Tp53. Levetiracetam-treated mice showed downregulation of retinal GLUT1 with relief and regression of retinal inflammation and improved retinal structural organization. SIGNIFICANCE Levetiracetam may represent a potential neuroprotective agent in DR. The data presented herein supported an anti-inflammatory role of levetiracetam. However, further clinical studies may be warranted to confirm the effectiveness and safety of levetiracetam in DR patients.
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Affiliation(s)
- Hala M F Mohammad
- Department of Clinical Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt; Central Lab., Center of Excellence in Molecular and Cellular Medicine (CEMCM), Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Manal M Sami
- Department of Pathology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Samy Makary
- Department of Medical Physiology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Eman A Toraih
- Genetics Unit, Department of Histology and Cell Biology, Faculty of Medicine, Suez Canal University, Ismailia 41522, Egypt; Molecular Lab, Center of Excellence of Molecular and Cellular Medicine, Suez Canal University, Ismailia, Egypt
| | - Amany O Mohamed
- Department of Medical Biochemistry, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Sabah H El-Ghaiesh
- Department of Pharmacology, Faculty of Medicine, Tanta University, Tanta, Egypt; Department of Pharmacology, Faculty of Medicine, University of Tabuk, Tabuk, Saudi Arabia.
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Othman R, Vaucher E, Couture R. Bradykinin Type 1 Receptor - Inducible Nitric Oxide Synthase: A New Axis Implicated in Diabetic Retinopathy. Front Pharmacol 2019; 10:300. [PMID: 30983997 PMCID: PMC6449803 DOI: 10.3389/fphar.2019.00300] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/11/2019] [Indexed: 12/15/2022] Open
Abstract
Compelling evidence suggests a role for the inducible nitric oxide synthase, iNOS, and the bradykinin type 1 receptor (B1R) in diabetic retinopathy, including a possible control of the expression and activity of iNOS by B1R. In diabetic retina, both iNOS and B1R contribute to inflammation, oxidative stress, and vascular dysfunction. The present study investigated whether inhibition of iNOS has any impact on inflammatory/oxidative stress markers and on the B1R-iNOS expression, distribution, and action in a model of type I diabetes. Diabetes was induced in 6-week-old Wistar rats by streptozotocin (65 mg.kg-1, i.p.). The selective iNOS inhibitor 1400W (150 μg.10 μl-1) was administered twice a day by eye-drops during the second week of diabetes. The retinae were collected 2 weeks after diabetes induction to assess the protein and gene expression of markers by Western blot and qRT-PCR, the distribution of iNOS and B1R by fluorescence immunocytochemistry, and the vascular permeability by the Evans Blue dye technique. Diabetic retinae showed enhanced expression of iNOS, B1R, carboxypeptidase M (involved in the biosynthesis of B1R agonists), IL-1β, TNF-α, vascular endothelium growth factor A (VEGF-A) and its receptor, VEGF-R2, nitrosylated proteins and increased vascular permeability. All those changes were reversed by treatment with 1400W. Moreover, the additional increase in vascular permeability in diabetic retina induced by intravitreal injection of R-838, a B1R agonist, was also prevented by 1400W. Immunofluorescence staining highlighted strong colocalization of iNOS and B1R in several layers of the diabetic retina, which was prevented by 1400W. This study suggests a critical role for iNOS and B1R in the early stage of diabetic retinopathy. B1R and iNOS appear to partake in a mutual auto-induction and amplification loop to enhance nitrogen species formation and inflammation in diabetic retina. Hence, B1R-iNOS axis deserves closer scrutiny in targeting diabetic retinopathy.
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Affiliation(s)
- Rahmeh Othman
- School of Optometry, University of Montreal, Montreal, QC, Canada.,Department of Pharmacology and Physiology, University of Montreal, Montreal, QC, Canada
| | - Elvire Vaucher
- School of Optometry, University of Montreal, Montreal, QC, Canada
| | - Réjean Couture
- Department of Pharmacology and Physiology, University of Montreal, Montreal, QC, Canada
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Nag TC, Kathpalia P, Gorla S, Wadhwa S. Localization of nitro-tyrosine immunoreactivity in human retina. Ann Anat 2019; 223:8-18. [PMID: 30716468 DOI: 10.1016/j.aanat.2019.01.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/15/2018] [Accepted: 01/08/2019] [Indexed: 12/16/2022]
Abstract
Oxidative stress (OS) is associated with retinal aging and age-related macular degeneration (AMD). In both cases there are reports for the presence of markers of lipid peroxidation in retinal cells. We investigated if nitrosative stress also occurs in the human retina with aging. We examined the cellular localization of nitro-tyrosine, a biomarker of protein tyrosine nitration, in human donor retina (17-91 years; N = 15) by immunohistochemistry. Immunoreactivity (IR) to nitro-tyrosine was present in ten retinas and absent in five retinas. It was predominant in photoreceptor inner segments, cell bodies and axons. In six retinas, IR was present in abnormal, swollen axons of macular and peripheral cones. In the inner retina, weak immunoreactivity was detected in the outer and inner plexiform layer. Transmission electron microscopy revealed a variable degree of microtubule disorganization, abnormal outgrowth from the swollen macular axons (as the fibers of Henle) and few dead axons. The present study adds further evidence to the presence of aberrant photoreceptor axonal changes in the human retina and that nitro-tyrosine immunoreactivity is associated with the photoreceptor cells in select human retina.
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Affiliation(s)
- Tapas C Nag
- Department of Anatomy, Neurobiology Laboratory, All India Institute of Medical Sciences, New Delhi, 110029, India.
| | - Poorti Kathpalia
- Department of Anatomy, Neurobiology Laboratory, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Shilpa Gorla
- Department of Anatomy, Neurobiology Laboratory, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Shashi Wadhwa
- Department of Anatomy, Neurobiology Laboratory, All India Institute of Medical Sciences, New Delhi, 110029, India
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Opatrilova R, Kubatka P, Caprnda M, Büsselberg D, Krasnik V, Vesely P, Saxena S, Ruia S, Mozos I, Rodrigo L, Kruzliak P, dos Santos KG. Nitric oxide in the pathophysiology of retinopathy: evidences from preclinical and clinical researches. Acta Ophthalmol 2018; 96:222-231. [PMID: 28391624 DOI: 10.1111/aos.13384] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 12/12/2016] [Indexed: 12/11/2022]
Abstract
Retinopathy is the leading cause of blindness and visual disability in working-aged people. The pathogenesis of retinopathy is an actual and still open query. Alterations contributing to oxidative and nitrosative stress, including elevated nitric oxide and superoxide production, changes in the expression of different isoforms of nitric oxide synthase or endogenous antioxidant system, have been implicated in the mechanisms how this ocular disease develops. In addition, it was documented that renin-angiotensin system has been implicated in the progression of retinopathy. Based on comprehensive preclinical and clinical researches in this area, the role of above-mentioned factors in the pathogenesis of diabetic retinopathy, hypertensive retinopathy and ischaemic proliferative retinopathy is reviewed in this study. Moreover, the genetic susceptibility factors involved in the development of the retinopathy and possible strategies that utilize antioxidants as additive therapy are also highlighted here.
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Affiliation(s)
- Radka Opatrilova
- Department of Chemical Drugs; Faculty of Pharmacy; University of Veterinary and Pharmaceutical Sciences; Brno Czech Republic
| | - Peter Kubatka
- Department of Medical Biology; Jessenius Faculty of Medicine; Comenius University in Bratislava; Martin Slovak Republic
- Division of Oncology; Biomedical Center Martin; Jessenius Faculty of Medicine; Comenius University in Bratislava; Martin Slovak Republic
| | - Martin Caprnda
- 2nd Department of Internal Medicine; Faculty of Pharmacy; Comenius University; Bratislava Slovakia
| | | | - Vladimir Krasnik
- Department of Ophthalmology; Faculty of Medicine; Comenius University; Bratislava Slovakia
| | | | - Sandeep Saxena
- Retina Service; Department of Ophthalmology; King George's Medical University; Lucknow India
| | - Surabhi Ruia
- Retina Service; Department of Ophthalmology; King George's Medical University; Lucknow India
| | - Ioana Mozos
- Department of Functional Sciences; “Victor Babes” University of Medicine and Pharmacy; Timisoara Romania
| | - Luis Rodrigo
- Faculty of Medicine; University of Oviedo; Central University Hospital of Asturias (HUCA); Oviedo Spain
| | - Peter Kruzliak
- Department of Chemical Drugs; Faculty of Pharmacy; University of Veterinary and Pharmaceutical Sciences; Brno Czech Republic
| | - Katia Goncalves dos Santos
- Laboratory of Human Molecular Genetics; Universidade Luterana do Brasil; Canoas Brazil
- Experimental and Molecular Cardiovascular Laboratory; Hospital de Clínicas de Porto Alegre; Porto Alegre Brazil
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Carr BC, Emigh CE, Bennett LD, Pansick AD, Birch DG, Nguyen C. TOWARDS A TREATMENT FOR DIABETIC RETINOPATHY: Intravitreal Toxicity and Preclinical Safety Evaluation of Inducible Nitric Oxide Synthase Inhibitors. Retina 2017; 37:22-31. [PMID: 27380429 DOI: 10.1097/iae.0000000000001133] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND The purpose of this study is to determine the maximum tolerated dose of a single intravitreal injection of aminoguanidine and 1400W, 2 inhibitors of inducible nitric oxide synthase, in rabbit eyes. Inhibition of inducible nitric oxide synthase has already been shown to be beneficial in various animal models of diabetic eye disease. METHODS Groups of 4 New Zealand white rabbits were injected with balanced salt solution in the right eye and a single dose of either aminoguanidine (5, 1, 0.25 mg) or 1400W (2 mg and 0.4 mg) in the left eye. Toxicity was assessed by slit-lamp and fundus examination, intraocular pressure and pachymetric measurements, and electrophysiologic and histologic analysis. RESULTS Eyes injected with high doses of aminoguanidine (5 mg) or 1400W (2 mg) demonstrated severe retinal vascular attenuation and infarction. Lower doses of intravitreal aminoguanidine (1 mg) and 1400W (0.4 mg) caused no significant toxic ocular effects in rabbit eyes. CONCLUSION If the difference in vitreal volume between rabbit eyes and human eyes is taken into account, aminoguanidine (2.7 mg) and 1400W (1 mg) would be reasonable intravitreal doses to test for safety and efficacy in early clinical trials.
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Affiliation(s)
- B Cameron Carr
- *Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas; and †Retina Foundation of the Southwest, Dallas, Texas
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Cheng L, Yu H, Yan N, Lai K, Xiang M. Hypoxia-Inducible Factor-1α Target Genes Contribute to Retinal Neuroprotection. Front Cell Neurosci 2017; 11:20. [PMID: 28289375 PMCID: PMC5326762 DOI: 10.3389/fncel.2017.00020] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 01/23/2017] [Indexed: 02/05/2023] Open
Abstract
Hypoxia-inducible factor (HIF) is a transcription factor that facilitates cellular adaptation to hypoxia and ischemia. Long-standing evidence suggests that one isotype of HIF, HIF-1α, is involved in the pathogenesis of various solid tumors and cardiac diseases. However, the role of HIF-1α in retina remains poorly understood. HIF-1α has been recognized as neuroprotective in cerebral ischemia in the past two decades. Additionally, an increasing number of studies has shown that HIF-1α and its target genes contribute to retinal neuroprotection. This review will focus on recent advances in the studies of HIF-1α and its target genes that contribute to retinal neuroprotection. A thorough understanding of the function of HIF-1α and its target genes may lead to identification of novel therapeutic targets for treating degenerative retinal diseases including glaucoma, age-related macular degeneration, diabetic retinopathy, and retinal vein occlusions.
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Affiliation(s)
- Lin Cheng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University Guangzhou, China
| | - Honghua Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen UniversityGuangzhou, China; Department of Ophthalmology, General Hospital of Guangzhou Military Command of PLAGuangzhou, China
| | - Naihong Yan
- Department of Ophthalmology and Ophthalmic Laboratories, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University Chengdu, China
| | - Kunbei Lai
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University Guangzhou, China
| | - Mengqing Xiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen UniversityGuangzhou, China; Center for Advanced Biotechnology and Medicine and Department of Pediatrics, Rutgers University-Robert Wood Johnson Medical SchoolPiscataway, NJ, USA
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Ezquer M, Urzua CA, Montecino S, Leal K, Conget P, Ezquer F. Intravitreal administration of multipotent mesenchymal stromal cells triggers a cytoprotective microenvironment in the retina of diabetic mice. Stem Cell Res Ther 2016; 7:42. [PMID: 26983784 PMCID: PMC4793534 DOI: 10.1186/s13287-016-0299-y] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/13/2016] [Accepted: 02/24/2016] [Indexed: 02/08/2023] Open
Abstract
Background Diabetic retinopathy is a common complication of diabetes and the leading cause of irreversible vision loss in the Western world. The reduction in color/contrast sensitivity due to the loss of neural cells in the ganglion cell layer of the retina is an early event in the onset of diabetic retinopathy. Multipotent mesenchymal stromal cells (MSCs) are an attractive tool for the treatment of neurodegenerative diseases, since they could differentiate into neuronal cells, produce high levels of neurotrophic factors and reduce oxidative stress. Our aim was to determine whether the intravitreal administration of adipose-derived MSCs was able to prevent the loss of retinal ganglion cells in diabetic mice. Methods Diabetes was induced in C57BL6 mice by the administration of streptozotocin. When retinal pro-damage mechanisms were present, animals received a single intravitreal dose of 2 × 105 adipose-derived MSCs or the vehicle. Four and 12 weeks later we evaluated: (a) retinal ganglion cell number (immunofluorescence); (b) neurotrophic factor levels (real-time quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA)); (c) retinal apoptotic rate (TUNEL); (d) retinal levels of reactive oxygen species and oxidative damage (ELISA); (e) electrical response of the retina (electroretinography); (f) pro-angiogenic and anti-angiogenic factor levels (RT-qPCR and ELISA); and (g) retinal blood vessels (angiography). Furthermore, 1, 4, 8 and 12 weeks post-MSC administration, the presence of donor cells in the retina and their differentiation into neural and perivascular-like cells were assessed (immunofluorescence and flow cytometry). Results MSC administration completely prevented retinal ganglion cell loss. Donor cells remained in the vitreous cavity and did not differentiate into neural or perivascular-like cells. Nevertheless, they increased the intraocular levels of several potent neurotrophic factors (nerve growth factor, basic fibroblast growth factor and glial cell line-derived neurotrophic factor) and reduced the oxidative damage in the retina. Additionally, MSC administration has a neutral effect on the electrical response of the retina and did not result in a pathological neovascularization. Conclusions Intravitreal administration of adipose-derived MSCs triggers an effective cytoprotective microenvironment in the retina of diabetic mice. Thus, MSCs represent an interesting tool in order to prevent diabetic retinopathy. Electronic supplementary material The online version of this article (doi:10.1186/s13287-016-0299-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marcelo Ezquer
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Av. Las Condes 12438, Lo Barnechea, Santiago, 7710162, Chile
| | - Cristhian A Urzua
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Chile, Av. Independencia 1027, Santiago, Chile
| | - Scarleth Montecino
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Av. Las Condes 12438, Lo Barnechea, Santiago, 7710162, Chile
| | - Karla Leal
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Av. Las Condes 12438, Lo Barnechea, Santiago, 7710162, Chile
| | - Paulette Conget
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Av. Las Condes 12438, Lo Barnechea, Santiago, 7710162, Chile
| | - Fernando Ezquer
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Av. Las Condes 12438, Lo Barnechea, Santiago, 7710162, Chile.
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Jung SH, Kim YS, Lee YR, Kim JS. High glucose-induced changes in hyaloid-retinal vessels during early ocular development of zebrafish: a short-term animal model of diabetic retinopathy. Br J Pharmacol 2015; 173:15-26. [PMID: 26276677 DOI: 10.1111/bph.13279] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 08/06/2015] [Accepted: 08/07/2015] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND AND PURPOSE Although a variety of animal models have been used to test drug candidates and examine the pathogenesis of diabetic retinopathy, time-saving and inexpensive models are still needed to evaluate the increasing number of therapeutic approaches. EXPERIMENTAL APPROACH We developed a model for diabetic retinopathy using the early stage of transgenic zebrafish (flk:EGFP) by treating embryos with 130 mM glucose, from 3-6 days post fertilisation (high-glucose model). On day 6, lenses from zebrafish larvae were isolated and treated with 3% trypsin, and changes in hyaloid-retinal vessels were analysed using fluorescent stereomicroscopy. In addition, expression of tight junction proteins (such as zonula occludens-1), effects of hyperosmolar solutions and of hypoxia, and Vegf expression were assessed by RT -PCR. NO production was assessed with a fluorescent substrate. Effects of inhibitors of the VEGF receptor, NO synthesis and a VEGF antibody (ranibizumab) were also measured. KEY RESULTS In this high-glucose model, dilation of hyaloid-retinal vessels, on day 6, was accompanied by morphological lesions with disruption of tight junction proteins, overproduction of Vegf mRNA and increased NO production. Treatment of this high-glucose model with an inhibitor of VEGF receptor tyrosine kinase or an inhibitor of NO synthase or ranibizumab decreased dilation of hyaloid-retinal vessels. CONCLUSIONS AND IMPLICATIONS These findings suggest that short-term exposure of zebrafish larvae to high-glucose conditions could be used for screening and drug discovery for diabetic retinopathy and particularly for disorders of retinal vessels related to disruption of tight junction proteins and excessive VEGF and NO production.
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Affiliation(s)
- Seung-Hyun Jung
- Korean Medicine Convergence Research Division, Korea Institute of Oriental Medicine (KIOM), Daejeon, 305-811, Korea
| | - Young Sook Kim
- Korean Medicine Convergence Research Division, Korea Institute of Oriental Medicine (KIOM), Daejeon, 305-811, Korea
| | - Yu-Ri Lee
- Korean Medicine Convergence Research Division, Korea Institute of Oriental Medicine (KIOM), Daejeon, 305-811, Korea
| | - Jin Sook Kim
- Korean Medicine Convergence Research Division, Korea Institute of Oriental Medicine (KIOM), Daejeon, 305-811, Korea
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Boynton GE, Stem MS, Kwark L, Jackson GR, Farsiu S, Gardner TW. Multimodal characterization of proliferative diabetic retinopathy reveals alterations in outer retinal function and structure. Ophthalmology 2015; 122:957-67. [PMID: 25601533 DOI: 10.1016/j.ophtha.2014.12.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 11/21/2014] [Accepted: 12/03/2014] [Indexed: 12/19/2022] Open
Abstract
PURPOSE To identify changes in retinal function and structure in persons with proliferative diabetic retinopathy (PDR), including the effects of panretinal photocoagulation (PRP). DESIGN Cross-sectional study. PARTICIPANTS Thirty adults who underwent PRP for PDR, 15 adults with untreated PDR, and 15 age-matched controls. METHODS Contrast sensitivity, frequency doubling perimetry (FDP), Humphrey visual fields, photostress recovery, and dark adaptation were assessed. Fundus photography and macular spectral-domain optical coherence tomography (SD OCT) were performed. To quantify retinal layer thicknesses, SD OCT scans were segmented semiautomatically. MAIN OUTCOME MEASURES Visual function measures were compared among patients with PDR and PRP, untreated patients with PDR, and controls. Mean retinal layer thicknesses were compared between groups. Correlation analyses were performed to evaluate associations between visual function measures and retinal layer thicknesses. RESULTS A significant reduction of FDP mean deviation (MD) was exhibited in PRP-treated patients with PDR (MD ± standard deviation, -8.20±5.76 dB; P < 0.0001) and untreated patients (-5.48±4.48 dB; P < 0.0001) relative to controls (1.07±2.50 dB). Reduced log contrast sensitivity compared with controls (1.80±0.14) also was observed in both PRP-treated patients (1.42±0.17; P < 0.0001) and untreated patients (1.56±0.20; P = 0.001) with PDR. Compared with controls, patients treated with PRP demonstrated increased photostress recovery time (151.02±104.43 vs. 70.64±47.14 seconds; P = 0.001) and dark adaptation speed (12.80±5.15 vs. 9.74±2.56 minutes; P = 0.022). Patients who underwent PRP had diffusely thickened nerve fiber layers (P = 0.024) and diffusely thinned retinal pigment epithelium (RPE) layers (P = 0.009) versus controls. Untreated patients with PDR also had diffusely thinned RPE layers (P = 0.031) compared with controls. CONCLUSIONS Patients with untreated PDR exhibited inner retinal dysfunction, as evidenced by reduced contrast sensitivity and FDP performance, accompanied by alterations in inner and outer retinal structure. Patients who underwent PRP had more profound changes in outer retinal structure and function. Distinguishing the effects of PDR and PRP may guide the development of restorative vision therapies for patients with advanced diabetic retinopathy.
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Affiliation(s)
- Grace E Boynton
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Maxwell S Stem
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
| | - Leon Kwark
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
| | | | - Sina Farsiu
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina; Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Thomas W Gardner
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan.
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Yafai Y, Eichler W, Iandiev I, Unterlauft JD, Jochmann C, Wiedemann P, Bringmann A. Thrombospondin-1 is produced by retinal glial cells and inhibits the growth of vascular endothelial cells. Ophthalmic Res 2014; 52:81-8. [PMID: 25138030 DOI: 10.1159/000362371] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 03/20/2014] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS By the release of antiangiogenic factors, Müller glial cells provide an angiostatic environment in the normal and ischemic retina. We determined whether Müller cells produce thrombospondin-1 (TSP-1), a known inhibitor of angiogenesis. METHODS Secretion of TSP-1 by cultured Müller cells was determined with ELISA. Slices of rat retinas and surgically excised retinal membranes of human subjects were immunostained against TSP-1 and the glial marker vimentin. The effects of TSP-1 on the growth of bovine retinal endothelial cells (BRECs) and activation of ERK1/2 were determined with DNA synthesis and migration assays, and Western blotting, respectively. RESULTS Cultured Müller cells secrete TSP-1 under normoxic and hypoxic (0.2% O2) conditions. Secretion of TSP-1 was increased in hypoxia compared to normoxia. In rat retinal slices, glial, retinal ganglion, and possibly horizontal cells were stained for TSP-1. Retinal glial cells in preretinal membranes from human subjects with nonhypoxic epiretinal gliosis (macular pucker) and proliferative diabetic retinopathy, respectively, were immunopositive for TSP-1. Exogenous TSP-1 reduced the VEGF-induced proliferation and migration of BRECs and decreased the phosphorylation level of ERK1/2 in BRECs. CONCLUSION The data suggest that Müller cells are one major source of TSP-1 in the normal and ischemic retina. Glia-derived TSP1 may inhibit angiogenic responses in the ischemic retina.
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Affiliation(s)
- Yousef Yafai
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
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Feng Y, Wang Y, Yang Z, Wu L, Hoffmann S, Wieland T, Gretz N, Hammes HP. Chronic hyperglycemia inhibits vasoregression in a transgenic model of retinal degeneration. Acta Diabetol 2014; 51:211-8. [PMID: 23771613 DOI: 10.1007/s00592-013-0488-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Accepted: 05/27/2013] [Indexed: 10/26/2022]
Abstract
Vasoregression characterizes diabetic retinopathy in animal models and in humans. We have recently demonstrated that vasoregression is earlier initiated in a rat model of ciliopathy-induced retinal neurodegeneration (TGR rat). The aim was to assess the balance between vasoregressive effects of chronic hyperglycemia and photoreceptor degeneration on adult vascular remodelling. The retinas were analyzed at 4 and 9 months after streptozotocin-induced diabetes. Neurodegeneration was determined by quantitation of cell numbers and retinal layer thickness. Vasoregression was assessed by quantitative retinal morphometry in retinal digest preparations. Retinal VEGF levels were measured by ELISA. Glial activation, expression and location of HSP27 and phosphorylated HSP27 were evaluated by immunofluorescence staining. Unexpectedly, the numbers of acellular capillaries were reduced at both time points and led to fewer intraretinal microvascular abnormalities in late stage diabetic TGR. Concomitantly, inner nuclear layers (INLs) in diabetic TGR rats were protected from cell loss at both time points. Consequently, glial activation was reduced, but VEGF level was increased in diabetic TGR retinas. Expressions of HSP27 were upregulated in glia cells in the preserved INL of diabetic TGR. Chronic hyperglycemia preserves the microvasculature in the retinal model of neurodegeneration. Cell preservation in the retinal INL was associated with protective gene regulation. Together, these data indicate that diabetes can induce vasoprotection, in which retinal glia can play a particular role.
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Affiliation(s)
- Y Feng
- 5th Medical Clinic, Faculty of Clinical Medicine, University of Heidelberg, Mannheim, Germany,
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Ezquer F, Ezquer M, Arango-Rodriguez M, Conget P. Could donor multipotent mesenchymal stromal cells prevent or delay the onset of diabetic retinopathy? Acta Ophthalmol 2014; 92:e86-95. [PMID: 23773776 DOI: 10.1111/aos.12113] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Diabetes mellitus is a complex metabolic disease that has become a global epidemic with more than 285 million cases worldwide. Major medical advances over the past decades have substantially improved its management, extending patients' survival. The latter is accompanied by an increased risk of developing chronic macro- and microvascular complications. Amongst them, diabetic retinopathy (DR) is the most common and frightening. Furthermore, during the past two decades, it has become the leading cause of visual loss. Irrespective of the type of diabetes, DR follows a well-known clinical and temporal course characterized by pericytes and neuronal cell loss, formation of acellular-occluded capillaries, occasional microaneurysms, increased leucostasis and thickening of the vascular basement membrane. These alterations progressively affect the integrity of retinal microvessels, leading to the breakdown of the blood-retinal barrier, widespread haemorrhage and neovascularization. Finally, tractional retinal detachment occurs leading to blindness. Nowadays, there is growing evidence that local inflammation and oxidative stress play pivotal roles in the pathogenesis of DR. Both processes have been associated with pericytes and neuronal degeneration observed early during DR progression. They may also be linked to sustained retinal vasculature damage that results in abnormal neovascularization. Currently, DR therapeutic options depend on highly invasive surgical procedures performed only at advanced stages of the disease, and which have proved to be ineffective to restore visual acuity. Therefore, the availability of less invasive and more effective strategies aimed to prevent or delay the onset of DR is highly desirable. Multipotent mesenchymal stromal cells, also referred to as mesenchymal stem cells (MSCs), are promising healing agents as they contribute to tissue regeneration by pleiotropic mechanisms, with no evidence of significant adverse events. Here, we revise the pathophysiology of DR to identify therapeutic targets for donor MSCs. Also, we discuss whether an MSC-based therapy could prevent or delay the onset of DR.
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Affiliation(s)
- Fernando Ezquer
- Institute of Science, Faculty of Medicine Clinica Alemana Universidad del Desarrollo, Lo Barnechea, Santiago, Chile
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Abu El-Asrar AM, Al-Mezaine HS, Ola MS. Pathophysiology and management of diabetic retinopathy. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.09.52] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Basic fibroblast growth factor contributes to a shift in the angioregulatory activity of retinal glial (Müller) cells. PLoS One 2013; 8:e68773. [PMID: 23861940 PMCID: PMC3701643 DOI: 10.1371/journal.pone.0068773] [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: 12/04/2011] [Accepted: 06/05/2013] [Indexed: 01/13/2023] Open
Abstract
Basic fibroblast growth factor (bFGF) is a pleiotropic cytokine with pro-angiogenic and neurotrophic effects. The angioregulatory role of this molecule may become especially significant in retinal neovascularization, which is a hallmark of a number of ischemic eye diseases. This study was undertaken to reveal expression characteristics of bFGF, produced by retinal glial (Müller) cells, and to determine conditions under which glial bFGF may stimulate the proliferation of retinal microvascular endothelial cells. Immunofluorescence labeling detected bFGF in Müller cells of the rat retina and in acutely isolated Müller cells with bFGF levels, which increased after ischemia-reperfusion in postischemic retinas. In patients with proliferative diabetic retinopathy or myopia, the immunoreactivity of bFGF co-localized to glial fibrillary acidic protein (GFAP)-positive cells in surgically excised retinal tissues. RT-PCR and ELISA analyses indicated that cultured Müller cells produce bFGF, which is elevated under hypoxia or oxidative stress, as well as under stimulation with various growth factors and cytokines, including pro-inflammatory factors. When retinal endothelial cells were cultured in the presence of media from hypoxia (0.2%)-conditioned Müller cells, a distinct picture of endothelial cell proliferation emerged. Media from 24-h cultured Müller cells inhibited proliferation, whereas 72-h conditioned media elicited a stimulatory effect. BFGF-neutralizing antibodies suppressed the enhanced endothelial cell proliferation to a similar extent as anti-VEGF antibodies. Furthermore, phosphorylation of extracellular signal-regulated kinases (ERK−1/−2) in retinal endothelial cells was increased when the cells were cultured in 72-h conditioned media, while neutralizing bFGF attenuated the activation of this signaling pathway. These data provide evidence that retinal (glial) Müller cells are major sources of bFGF in the ischemic retina. Müller cells under physiological conditions or transient hypoxia seem to provide an anti-angiogenic environment, but long-lasting hypoxia causes the release of bFGF, which might significantly co-stimulate neovascularization in the retina.
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El-Asrar AMA. Role of inflammation in the pathogenesis of diabetic retinopathy. Middle East Afr J Ophthalmol 2012; 19:70-4. [PMID: 22346117 PMCID: PMC3277027 DOI: 10.4103/0974-9233.92118] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Diabetic retinopathy (DR) remains a major cause of worldwide preventable blindness. The microvasculature of the retina responds to hyperglycemia through a number of biochemical changes, including activation of protein kinase C, increased advanced glycation end products formation, polyol pathway, and oxidative stress, and activation of the renin angiotensin system (RAS). There is an accumulating body of evidence that inflammation plays a prominent role in the pathogenesis of DR.
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Affiliation(s)
- Ahmed M Abu El-Asrar
- Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
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Coorey NJ, Shen W, Chung SH, Zhu L, Gillies MC. The role of glia in retinal vascular disease. Clin Exp Optom 2012; 95:266-81. [PMID: 22519424 DOI: 10.1111/j.1444-0938.2012.00741.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Retinal vascular diseases collectively represent a leading cause of blindness. Unsurprisingly, pathological characterisation and treatment of retinal 'vascular' diseases have primarily focused on the aetiology and consequences of vascular dysfunction. Far less research has addressed the contribution of neuronal and glial dysfunction to the disease process of retinal vascular disorders. Ample evidence now suggests that retinal vasculopathy only uncommonly occurs in isolation, usually existing in concert with neuropathy and gliopathy. Retinal glia (Müller cells, astrocytes and microglia) have been reported to exhibit morphological and functional changes in both early and advanced phases of almost every retinal vascular disease. It is anticipated that identifying the causes of glial activation and dysfunction, and their contribution to loss of vision in retinal vascular disease, will lead to a better understanding of retinal vascular diseases, which might ultimately be translated into novel clinical therapies.
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Affiliation(s)
- Nathan J Coorey
- Save Sight Institute, The University of Sydney, Sydney, Australia
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Dai Y, Weinreb RN, Kim KY, Nguyen D, Park S, Sun X, Lindsey JD, Ellisman MH, Ju WK. Inducible nitric oxide synthase-mediated alteration of mitochondrial OPA1 expression in ocular hypertensive rats. Invest Ophthalmol Vis Sci 2011; 52:2468-76. [PMID: 21220562 DOI: 10.1167/iovs.10-5873] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate how OPA1 expression and distribution are altered by increased nitric oxide (NO) and whether aminoguanidine, a relative selective NO synthase (NOS)-2 inhibitor, can restore OPA1 expression and subsequently increase retinal ganglion cell (RGC) survival in ocular hypertensive rats. METHODS Elevated intraocular pressure was induced unilaterally by translimbal laser photocoagulation of the trabecular meshwork in Sprague-Dawley rats. Aminoguanidine (100 mg/kg) was administered by intraperitoneal injection for 3 consecutive days in rats after laser treatment. Preservation of fluorochrome-labeled RGCs was assessed 2 weeks later. GFAP, NOS-2, or OPA1 protein expression and distribution were assessed by Western blot analysis and immunohistochemistry. OPA1 mRNA was measured by qPCR. RESULTS OPA1 mRNA and protein expression were significantly increased in the vehicle-treated hypertensive rat retina. Aminoguanidine treatment significantly reduced expression of the 90- and 65-kDa OPA1 isoforms but did not significantly change the 80-kDa OPA1 isoform in hypertensive retina. In addition, the increases in NOS-2 and GFAP protein expression were blocked by aminoguanidine treatment in the hypertensive retina. NOS-2 immunoreactivity was induced in cells of the ganglion cell layer in the vehicle-treated hypertensive retina. Aminoguanidine treatment significantly increased RGC survival at 2 weeks after IOP elevation. CONCLUSIONS Although NOS-2/NO induction may contribute to hypertensive retinal cell death, an increase in mitochondrial OPA1 may provide an important cellular defense mechanism against pressure-mediated retinal damage. These findings suggest that mitochondrial preservation after inhibition of NOS-2 may be useful for protecting RGCs against glaucomatous damage.
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Affiliation(s)
- Yi Dai
- The Sophie and Arthur Brody Optic Nerve Laboratory, Hamilton Glaucoma Center, University of California San Diego, La Jolla, California, USA
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Liu Y, Song X, Han Y, Zhou F, Zhang D, Ji B, Hu J, Lv Y, Cai S, Wei Y, Gao F, Jia X. Identification of anthocyanin components of wild Chinese blueberries and amelioration of light-induced retinal damage in pigmented rabbit using whole berries. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:356-363. [PMID: 21142104 DOI: 10.1021/jf103852s] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Studies suggest that the consumption of berry fruits rich in anthocyanins may have beneficial effects on improving visual function. This study determined the total polyphenol and total anthocyanin contents in wild Chinese blueberries using the Folin-Ciocalteu reagent method and a pH differential method. Anthocyanin composition and quantity were characterized by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry coupled with mass selective detection. Total polyphenol and anthocyanin contents were 602.9 ± 9.2 and 177.8 ± 8.3 mg/100 g, respectively. Seventeen anthocyanins were discovered, and only 13 were tentatively identified in the wild blueberries. Anthocyanins of malvidin glycosylated with hexose or pentose accounted for >46% of total anthocyanin content. Furthermore, the effect of whole blueberries on retinal damage in pigmented rabbits upon light exposure was investigated, and the retinal functions were evaluated by electroretinogram (ERG). Pigmented rabbits were chosen for this experiment because of their large eyes, which facilitated the operative procedure and observation, and the similarity of their eyes to the human eye structure. Light-induced retinal damage was induced by exposure to white light at 15000 ± 1000 lx for 2 h. Feeding the rabbits with blueberries at a dosage of 1.2 or 4.9 g/kg/day for 4 weeks prior to light exposure effectively reduced photodamage to the retinas. This study adds to the growing body of data supporting the bioactivity of blueberries in improving mammal vision.
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Affiliation(s)
- Yixiang Liu
- Functional Food Research Laboratory, College of Food Science and Nutritional Engineering, China Agricultural University, Haidian District, Beijing, China
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Shen W, Li S, Chung SH, Gillies MC. Retinal vascular changes after glial disruption in rats. J Neurosci Res 2010; 88:1485-99. [PMID: 20029988 DOI: 10.1002/jnr.22317] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Glial dysfunction is found in a number of retinal vascular diseases but its link with blood-retinal barrier (BRB) breakdown remains poorly understood. The present study tested the hypothesis that glial dysfunction is a major contributor to the BRB breakdown that is a hallmark of retinal vascular diseases. We investigated the specificity of the purportedly selective glial toxin, DL-alpha-aminoadipic acid (DL-alpha-AAA) on different types of ocular cells in vitro and then tested the effect of glial disruption on retinal vasculature after intraocular injection of DL-alpha-AAA or siRNA targeting glutamine synthetase (GS) in rats. DL-alpha-AAA was toxic to astrocytes and Müller cells but not to other types of BRB-related cells in vitro. Subretinal injection of DL-alpha-AAA disrupted retinal glial cells, induced vascular telangiectasis and increased vascular permeability from 4 days to over 2 months post-injection. Vascular changes induced by DL-alpha-AAA were observed predominantly in regions of glial disruption, as reflected by reduced expression of GS and increased expression of glial fibrillary acidic protein and vimentin. Confocal microscopy showed changes in all three layers of the retinal vasculature, which co-localised with areas of Müller cell disruption. Double labeling immunohistochemistry revealed that retinal glial disruption after DL-alpha-AAA injection was accompanied by increased expression of vascular endothelial growth factor and reduced expression of the tight junction protein claudin-5. Intravitreal injection of GS siRNA induced similar changes in Müller cells and BRB breakdown. Our data are consistent with the hypothesis that glial dysfunction is a primary contributor to the BRB breakdown in retinal vascular diseases.
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Affiliation(s)
- Weiyong Shen
- Save Sight Institute, University of Sydney, Sydney, Australia.
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Li J, Wang JJ, Yu Q, Chen K, Mahadev K, Zhang SX. Inhibition of reactive oxygen species by Lovastatin downregulates vascular endothelial growth factor expression and ameliorates blood-retinal barrier breakdown in db/db mice: role of NADPH oxidase 4. Diabetes 2010; 59:1528-38. [PMID: 20332345 PMCID: PMC2874715 DOI: 10.2337/db09-1057] [Citation(s) in RCA: 158] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Oxidative stress is a key pathogenic factor in diabetic retinopathy. We previously showed that lovastatin mitigates blood-retinal barrier (BRB) breakdown in db/db mice. The purpose of this study is to determine the mechanisms underlying the salutary effects of lovastatin in diabetic retinopathy. RESEARCH DESIGN AND METHODS Expression of NADPH oxidase (Nox) 4, vascular endothelial growth factor (VEGF), and hypoxia-inducible factor (HIF)-1alpha; production of reactive oxygen species (ROS); and retinal vascular permeability were measured in cultured retinal capillary endothelial cells (RCECs) and in db/db mice treated with lovastatin. RESULTS Expressions of Nox4 and VEGF were significantly increased in retinas of db/db mice and reduced by lovastatin treatment. In cultured RCECs, hypoxia and high glucose upregulated mRNA and protein expression of Nox4, ROS generation, and VEGF level. These changes were abrogated by pretreatment with lovastatin or NADPH oxidase inhibitor diphenyleneiodonium chloride. Overexpression of Nox4 increased basal level of ROS generation, HIF-1alpha, and VEGF expression in RCECs. In contrast, blockade of Nox4 activity using adenovirus-expressing dominant-negative Nox4 abolished hypoxia- and high-glucose-induced ROS production and VEGF expression. Moreover, inhibition of Nox4 attenuated hypoxia-induced upregulation of HIF-1alpha and high-glucose-elicited phosphorylation of STAT3. Finally, depletion of Nox4 by adenovirus-delivered Nox4 small interfering RNA significantly decreased retinal NADPH oxidase activity and VEGF expression and reduced retinal vascular premeability in db/db mice. CONCLUSIONS Activation of Nox4 plays an important role in high-glucose- and hypoxia-mediated VEGF expression and diabetes-induced BRB breakdown. Inhibition of Nox4, at least in part, contributes to the protective effects of lovastatin in diabetic retinopathy.
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Affiliation(s)
- Jingming Li
- Harold Hamm Oklahoma Diabetes Center and Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Joshua J. Wang
- Harold Hamm Oklahoma Diabetes Center and Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Qiang Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Kai Chen
- Department of Medicine, Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Kalyankar Mahadev
- Division of Endocrinology, Diabetes, and Metabolic Diseases, Department of Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Sarah X. Zhang
- Harold Hamm Oklahoma Diabetes Center and Section of Endocrinology and Diabetes, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
- Corresponding author: Sarah X. Zhang,
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Arnal E, Miranda M, Johnsen-Soriano S, Alvarez-Nölting R, Díaz-Llopis M, Araiz J, Cervera E, Bosch-Morell F, Romero FJ. Beneficial effect of docosahexanoic acid and lutein on retinal structural, metabolic, and functional abnormalities in diabetic rats. Curr Eye Res 2010; 34:928-38. [PMID: 19958109 DOI: 10.3109/02713680903205238] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To assess the effect of docosahexanoic acid (DHA) and lutein (both compounds with anti-inflammatory and antioxidant properties) on experimental diabetic retinopathy. METHODS Male Wistar rats were studied: non-diabetic controls, untreated diabetic controls, and diabetic rats were treated with DHA and lutein or the combination of DHA + insulin and lutein + insulin for 12 weeks. Oxidative stress and inflammatory markers, apoptosis, and functional tests were studied to confirm biochemical and functional changes in the retina of diabetic rats. Malondialdehyde (MDA), glutathione concentrations (GSH), and glutathione peroxidase activity (GPx) were measured as oxidative stress markers. TUNEL assay and caspase-3 immunohistochemistry and electroretinogram were performed. RESULTS Diabetes increases oxidative stress, nitrotyrosine concentrations, and apoptosis in the retina. At 12 weeks after onset of diabetes, total thickness of retinas of diabetic rats was significantly less than that in control rats. Specifically, the thickness of the outer and inner nuclear layers was reduced significantly in diabetic rats and demonstrated a loss of cells in the GCL. These retinal changes were avoided by the administration of insulin and DHA and lutein alone or in combination with insulin. Impairment of the electroretinogram (b-wave amplitude and latency time) was observed in diabetic rats. DHA and lutein prevented all these changes even under hyperglycemic conditions. CONCLUSIONS Lutein and DHA are capable of normalizing all the diabetes-induced biochemical, histological, and functional modifications. Specifically, the cell death mechanisms involved deserve further studies to allow the proposal as potential adjuvant therapies to help prevent vision loss in diabetic patients.
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Affiliation(s)
- Emma Arnal
- Ophthalmological Mediterranean Foundation, Valencia, Spain
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DeNiro M, Al-Halafi A, Al-Mohanna FH, Alsmadi O, Al-Mohanna FA. Pleiotropic effects of YC-1 selectively inhibit pathological retinal neovascularization and promote physiological revascularization in a mouse model of oxygen-induced retinopathy. Mol Pharmacol 2009; 77:348-67. [PMID: 20008515 DOI: 10.1124/mol.109.061366] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vascular endothelial growth factor (VEGF) and inducible nitric-oxide synthase (iNOS) have been implicated in ischemia-induced retinal neovascularization. Retinal ischemia has been shown to induce VEGF and iNOS expression. It has been postulated that one of the crucial consequences of iNOS expression in the ischemic retina is the inhibition of angiogenesis. Furthermore, iNOS was shown to be overexpressed in Müller cells from patients with diabetic retinopathy. YC-1, a small molecule inhibitor of hypoxia-inducible factor (HIF)-1 alpha, has been shown to inhibit iNOS expression in various tissue models. Our aim was to assess the pleiotropic effects of YC-1 in an oxygen-induced retinopathy (OIR) mouse model and evaluate its therapeutic potential in HIF-1- and iNOS-mediated retinal pathologies. Dual-injections of YC-1 into the neovascular retinas decreased the total retinopathy score, inhibited vaso-obliteration and pathologic tuft formation, and concomitantly promoted physiological retinal revascularization, compared with dimethyl sulfoxide (DMSO)-treated group. Furthermore, YC-1-treated retinas exhibited a marked increase in immunoreactivities for CD31 and von Willebrand factor and displayed significant inhibition in HIF-1alpha protein expression. Furthermore, YC-1 down-regulated VEGF, erythropoietin, endothelin-1, matrix metalloproteinase-9, and iNOS message and protein levels. When hypoxic Müller and neuoroglial cells were treated with YC-1, iNOS mRNA and protein levels were reduced in a dose-dependent fashion. We demonstrate that YC-1 inhibits pathological retinal neovascularization by exhibiting antineovascular activities, which impaired ischemia-induced expression of HIF-1 and its downstream angiogenic molecules. Furthermore, YC-1 enhanced physiological revascularization of the retinal vascular plexuses via the inhibition of iNOS mRNA and protein expressions. The pleiotropic effects of YC-1 allude to its possible use as a promising therapeutic iNOS inhibitor candidate for the treatment of retinal neovascularization.
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Affiliation(s)
- M DeNiro
- Research Department, King Khaled Eye Specialist Hospital, Aruba Street, P.O. Box.7191, Riyadh 11462, Kingdom of Saudi Arabia.
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Bringmann A, Wiedemann P. Involvement of Müller glial cells in epiretinal membrane formation. Graefes Arch Clin Exp Ophthalmol 2009; 247:865-83. [PMID: 19415318 DOI: 10.1007/s00417-009-1082-x] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 02/10/2009] [Accepted: 04/06/2009] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Proliferative retinopathies are considered to represent maladapted retinal wound repair processes driven by growth factor- and cytokine-induced overstimulation of proliferation, migration, extracellular matrix production and contraction of retinal cells. The formation of neovascular membranes represents an attempt to reoxygenize non-perfused retinal areas. Müller glial cells play a crucial role in the pathogenesis of proliferative retinopathies. This review summarizes the present knowledge regarding the role of Müller cells in periretinal membrane formation, especially in the early steps of epiretinal membrane formation, which involve an interaction of inflammatory and glial cells, and gives a survey of the factors which are suggested to be implicated in the induction of Müller cell gliosis and proliferation. CONCLUSIONS Alterations in the membrane conductance of Müller cells suggest that Müller cells may alter their phenotype into progenitor-like cells in the course of proliferative retinopathies; transdifferentiated Müller cells may have great impact for the development of new cell-based therapies.
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Affiliation(s)
- Andreas Bringmann
- Department of Ophthalmology, Faculty of Medicine, University of Leipzig, Eye Hospital, Leipzig, Germany.
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Renno WM, Alkhalaf M, Afsari Z, Abd-El-Basset E, Mousa A. Consumption of green tea alters glial fibriliary acidic protein immunoreactivity in the spinal cord astrocytes of STZ-diabetic rats. Nutr Neurosci 2009; 11:32-40. [PMID: 18510801 DOI: 10.1179/147683008x301405] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We examined the effect of green tea consumption on glial fibriliary acidic protein (GFAP) expression in spinal cord of streptozotocin (STZ) treated rats. Three groups (n = 10) were used in this study: (i) controls; (ii) STZ-induced diabetic rats given tap water; and (iii) an STZ-induced diabetic group given green tea. Immunohistochemistry showed a significant (P < 0.001) decrease in the number of GFAP immunoreactive astrocytes in spinal cord sections of diabetic rats compared to non-diabetic controls. Diabetic rats treated with green tea showed a significant (P < 0.01) increase in the number GFAP-immunoreactive astrocytes in all the spinal cord gray areas as compared to water-drinking diabetic rats. Immunoblotting confirmed that the diabetic spinal cord tissue expressed 71.0 +/- 7.0% less GFAP compared to non-diabetic controls and that the GFAP content in diabetic rats increased up to 86.34 +/- 18.74% compared to non-diabetic controls after 12 weeks of green tea consumption. In conclusion, consumption of green tea may represent an achievable adjunct therapy for improving changes seen in diabetic spinal cord.
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Affiliation(s)
- Waleed M Renno
- Department of Anatomy, Faculty of Medicine, Health Sciences Center, University of Kuwait, Kuwait.
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Smith SB, Duplantier J, Dun Y, Mysona B, Roon P, Martin PM, Ganapathy V. In vivo protection against retinal neurodegeneration by sigma receptor 1 ligand (+)-pentazocine. Invest Ophthalmol Vis Sci 2008; 49:4154-61. [PMID: 18469181 PMCID: PMC2562718 DOI: 10.1167/iovs.08-1824] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To evaluate the neuroprotective properties of the sigma receptor 1 (sigmaR1) ligand, (+)-pentazocine in an in vivo model of retinal neurodegeneration. METHODS Spontaneously diabetic Ins2(Akita/+) and wild-type mice received intraperitoneal injections of (+)-pentazocine for 22 weeks beginning at diabetes onset. Retinal mRNA and protein were analyzed by RT-PCR and Western blot analysis. Retinal histologic sections were measured to determine total retinal thickness, thicknesses of inner-outer nuclear and plexiform layers (INL, ONL, IPL, INL), and the number of cell bodies in the ganglion cell layer (GCL). Immunolabeling experiments were performed using antibodies specific for 4-hydroxynonenal and nitrotyrosine, markers of lipid peroxidation, and reactive nitrogen species, respectively, and an antibody specific for vimentin to view radial Müller fibers. RESULTS sigmaR1 mRNA and protein levels in the Ins2(Akita/+) retina were comparable to those in the wild-type, indicating that sigmaR1 is an available target during the disease process. Histologic evaluation of eyes of Ins2(Akita/+) mice showed disruption of retinal architecture. By 17 to 25 weeks after birth, Ins2(Akita/+) mice demonstrated approximately 30% and 25% decreases in IPL and INL thicknesses, respectively, and a 30% reduction in ganglion cells. In the (+)-pentazocine-treated group, retinas of Ins2(Akita/+) mice showed remarkable preservation of retinal architecture; IPL and INL thicknesses of (+)-pentazocine-treated Ins2(Akita/+) mouse retinas were within normal limits. The number of ganglion cells was 15.6 +/- 1.5 versus 10.4 +/- 1.2 cells/100 mum retinal length in (+)-pentazocine-treated versus nontreated mutant mice. Levels of nitrotyrosine and 4-hydroxynonenal increased in Ins2(Akita/+) retinas, but were reduced in (+)-pentazocine-treated mice. Retinas of Ins2(Akita/+) mice showed loss of the uniform organization of radial Müller fibers. Retinas of (+)-pentazocine-treated mice maintained the radial organization of glial processes. CONCLUSION Sustained (+)-pentazocine treatment in an in vivo model of retinal degeneration conferred significant neuroprotection, reduced evidence of oxidative stress, and preserved retinal architecture, suggesting that sigmaR1 ligands are promising therapeutic agents for intervention in neurodegenerative diseases of the retina.
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Affiliation(s)
- Sylvia B Smith
- Departments of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, Georgia, USA.
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Penn JS, Madan A, Caldwell RB, Bartoli M, Caldwell RW, Hartnett ME. Vascular endothelial growth factor in eye disease. Prog Retin Eye Res 2008; 27:331-71. [PMID: 18653375 DOI: 10.1016/j.preteyeres.2008.05.001] [Citation(s) in RCA: 519] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Collectively, angiogenic ocular conditions represent the leading cause of irreversible vision loss in developed countries. In the US, for example, retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration are the principal causes of blindness in the infant, working age and elderly populations, respectively. Evidence suggests that vascular endothelial growth factor (VEGF), a 40kDa dimeric glycoprotein, promotes angiogenesis in each of these conditions, making it a highly significant therapeutic target. However, VEGF is pleiotropic, affecting a broad spectrum of endothelial, neuronal and glial behaviors, and confounding the validity of anti-VEGF strategies, particularly under chronic disease conditions. In fact, among other functions VEGF can influence cell proliferation, cell migration, proteolysis, cell survival and vessel permeability in a wide variety of biological contexts. This article will describe the roles played by VEGF in the pathogenesis of retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration. The potential disadvantages of inhibiting VEGF will be discussed, as will the rationales for targeting other VEGF-related modulators of angiogenesis.
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Affiliation(s)
- J S Penn
- Vanderbilt University School of Medicine, Nashville, TN, USA.
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Afsari ZH, Renno WM, Abd-El-Basset E. Alteration of glial fibrillary acidic proteins immunoreactivity in astrocytes of the spinal cord diabetic rats. Anat Rec (Hoboken) 2008; 291:390-9. [PMID: 18360886 DOI: 10.1002/ar.20678] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Diabetes affects retinal and nervous glial cells, especially the astrocytes. A key indicator of this response is the alteration in the level of intermediate filament glial fibrillary acidic protein (GFAP) and number of GFAP-immunoreactive astrocytes. To date, no study has investigated the effect of diabetes on the distribution of GFAP-immunoreactive astrocytes in the spinal cord. Therefore, the present study investigated the effect of diabetes on the number of GFAP-immunoreactive astrocytes in the gray matter of the spinal cord of streptozotocin-induced diabetic Wistar rats. Animals were divided into six groups (n = 7); 6 weeks and 12 weeks diabetic duration groups and their respective age-matched normal control and sham control groups. Our results demonstrated a significant (P < 0.001) decrease in the number of GFAP-immunoreactive astrocytes in different areas of the spinal cord sections of the 6 weeks and 12 weeks long diabetic rats when compared with the spinal cord of normal and sham control groups of comparable age. The mean percentage in total number of GFAP-immunoreactive astrocytes in the whole gray matter areas of the spinal cord of the 6 and 12 weeks diabetic groups were approximately 28% and 41% less than control groups. Furthermore, the 12 weeks diabetic group showed a significant (P < 0.001) reduction in the number of GFAP-immunoreactive astrocytes when compared with the 6 weeks diabetic animals. These results suggest that the induction of diabetes is associated with a reduction in GFAP-positive astrocytes in the spinal cord, which may affect the functional support and role of astrocytic cells in the nervous tissue. This in turn may contribute to the pathological changes associated with diabetic state in the central nervous system.
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Affiliation(s)
- Zainab H Afsari
- Department of Anatomy, Faculty of Medicine, Health Sciences Center, University of Kuwait
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Zheng L, Du Y, Miller C, Gubitosi-Klug RA, Kern TS, Ball S, Berkowitz BA. Critical role of inducible nitric oxide synthase in degeneration of retinal capillaries in mice with streptozotocin-induced diabetes. Diabetologia 2007; 50:1987-1996. [PMID: 17583794 DOI: 10.1007/s00125-007-0734-9] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Accepted: 04/30/2007] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Diabetes results in the upregulation of the production of several components of the inflammatory response in the retina, including inducible nitric oxide synthase (iNOS). The aim of this study was to investigate the role of iNOS in the pathogenesis of the early stages of diabetic retinopathy using iNOS-deficient mice (iNos (-/-)). MATERIALS AND METHODS iNos (-/-) mice and wild-type (WT; C57BL/6J) mice were made diabetic with streptozotocin or kept as non-diabetic controls. Mice were killed at different time points after the induction of diabetes for assessment of vascular histopathology, cell loss in the ganglion cell layer (GCL), retinal thickness, and biochemical and physiological abnormalities. RESULTS The concentrations of nitric oxide, nitration of proteins, poly(ADP-ribose) (PAR)-modified proteins, endothelial nitric oxide synthase, prostaglandin E(2), superoxide and leucostasis were significantly (p < 0.05) increased in retinas of WT mice diabetic for 2 months compared with non-diabetic WT mice. All of these abnormalities except PAR-modified proteins in retinas were inhibited (p < 0.05) in diabetic iNos (-/-) mice. The number of acellular capillaries and pericyte ghosts was significantly increased in retinas from WT mice diabetic for 9 months compared with non-diabetic WT controls, these increases being significantly inhibited in diabetic iNos (-/-) mice (p < 0.05 for all). Retinas from WT diabetic mice were significantly thinner than those from their non-diabetic controls, whereas diabetic iNos (-/-) mice were protected from this abnormality. We found no evidence of cell loss in the GCL of diabetic WT or iNos (-/-) mice. Deletion of iNos had no beneficial effect on diabetes-induced abnormalities on the electroretinogram. CONCLUSIONS/INTERPRETATION We demonstrate that the inflammatory enzyme iNOS plays an important role in the pathogenesis of vascular lesions characteristic of the early stages of diabetic retinopathy in mice.
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Affiliation(s)
- L Zheng
- Department of Medicine, 448B Biomedical Research Building, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
| | - Y Du
- Department of Medicine, 448B Biomedical Research Building, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - C Miller
- Department of Medicine, 448B Biomedical Research Building, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Alcon Research, Fort Worth, TX, USA
| | - R A Gubitosi-Klug
- Department of Pediatrics, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, OH, USA
| | - T S Kern
- Department of Medicine, 448B Biomedical Research Building, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
- Department of Ophthalmology, 434 Biomedical Research Building, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
- Cleveland VAMC Research Service 151, Cleveland, OH, USA.
| | - S Ball
- Cleveland VAMC Research Service 151, Cleveland, OH, USA
| | - B A Berkowitz
- Department of Anatomy and Cell Biology, Wayne State University, Detroit, MI, USA
- Department of Ophthalmology, Wayne State University, Detroit, MI, USA
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Steinle JJ. Sympathetic neurotransmission modulates expression of inflammatory markers in the rat retina. Exp Eye Res 2006; 84:118-25. [PMID: 17067575 DOI: 10.1016/j.exer.2006.09.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Revised: 09/08/2006] [Accepted: 09/11/2006] [Indexed: 11/16/2022]
Abstract
Recent evidence suggests that diabetic retinopathy may involve some components of chronic inflammation. Since surgical sympathectomy produces most of the retinal changes noted in the retina of an STZ-treated rat in a non-diabetic rat, we wanted to determine whether sympathetic neurotransmission regulates gene and protein expression of inducible nitric oxide synthase (iNOS) and the prostaglandin (PGE2) receptor, as well as the levels of PGE2. Real-time PCR was conducted on retinal samples from rats that were surgically sympathectomized to investigate steady-state mRNA expression of iNOS in the sympathectomized and contralateral retina. Western blot analysis was done on protein samples from the sympathectomized and contralateral retina for iNOS and PGE2-EP2 receptor. An ELISA assay was done on retinal supernatant fractions to measure PGE2 levels. Additionally, human retinal endothelial cells were grown in either low (5 mM) or high (25 mM) glucose medium and stimulated with isoproterenol (beta-adrenergic receptor agonist), xamoterol (beta1-adrenergic receptor subtype agonist), or BRL37344 (beta3-adrenergic receptor subtype agonist) and the effects of agonist stimulation on iNOS and PGE2 levels in low and high glucose was investigated. Sympathectomy significantly increases gene and protein expression of iNOS, as well as levels of PGE2 and protein expression of PGE2-EP2 receptor subtype. Isoproterenol treatment for 6 h to human retinal endothelial cells grown in high glucose medium reduced iNOS protein expression, but had no effect on PGE2 levels or PGE2 receptor protein expression. iNOS expression was attenutated by stimulation with xamoterol, while BRL37344 had no effect, suggesting that the iNOS effects are mediated by beta1-adrenergic receptors. These results suggest that loss of sympathetic activity, as occurs in diabetes, results in an upregulation of iNOS and PGE2-EP2 receptor protein expression, as well as PGE2 levels. Isoproterenol stimulation of human retinal endothelial cells cultured in a hyperglycemic environment decreased iNOS expression with no change in PGE2 levels, suggesting that only iNOS expression is modulated by sympathetic neurotransmission in endothelial cells. Overall, these results further the idea that alterations in sympathetic neurotransmission may result in many of the changes noted in the retina of the STZ-treated rat.
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Affiliation(s)
- Jena J Steinle
- Department of Physiology, Southern Illinois University School of Medicine, 1135 Lincoln Drive, LS III Room 2071, Carbondale, IL 62901, USA.
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Farhangkhoee H, Khan ZA, Kaur H, Xin X, Chen S, Chakrabarti S. Vascular endothelial dysfunction in diabetic cardiomyopathy: pathogenesis and potential treatment targets. Pharmacol Ther 2005; 111:384-99. [PMID: 16343639 DOI: 10.1016/j.pharmthera.2005.10.008] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Accepted: 10/13/2005] [Indexed: 12/24/2022]
Abstract
Cardiovascular complications account for significant morbidity and mortality in the diabetic population. Diabetic cardiomyopathy, a prominent cardiovascular complication, has been recognized as a microvascular disease that may lead to heart failure. Pathogenesis of diabetic cardiomyopathy involves vascular endothelial cell dysfunction, as well as myocyte necrosis. Clinical trials have identified hyperglycemia as the key determinant in the development of chronic diabetic complications. Sustained hyperglycemia induces several biochemical changes including increased non-enzymatic glycation, sorbitol-myoinositol-mediated changes, redox potential alterations, and protein kinase C (PKC) activation, all of which have been implicated in diabetic cardiomyopathy. Other contributing metabolic abnormalities may include defective glucose transport, increased myocyte fatty acid uptake, and dysmetabolism. These biochemical changes manifest as hemodynamic alterations and structural changes that include capillary basement membrane (BM) thickening, interstitial fibrosis, and myocyte hypertrophy and necrosis. Diabetes-mediated biochemical anomalies show cross-interaction and complex interplay culminating in the activation of several intracellular signaling molecules. Studies in both animal and human diabetes have shown alteration of several factors including vasoactive molecules that may be instrumental in mediating structural and functional deficits at both the early and the late stages of the disease. In this review, we will highlight some of the important vascular changes leading to diabetic cardiomyopathy and discuss the emerging potential therapeutic interventions.
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Affiliation(s)
- Hana Farhangkhoee
- Department of Pathology, University of Western Ontario, London, Ontario, Canada
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Chen SH, Babichev Y, Rodrigues N, Voskas D, Ling L, Nguyen VPKH, Dumont DJ. Gene expression analysis of Tek/Tie2 signaling. Physiol Genomics 2005; 22:257-67. [PMID: 15899944 DOI: 10.1152/physiolgenomics.00063.2005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The elaboration of the vasculature during embryonic development involves restructuring of the early vessels into a more complex vascular network. Of particular importance to this vascular remodeling process is the requirement of the Tek/Tie2 receptor tyrosine kinase. Mouse gene-targeting studies have shown that the Tie2-deficient embryos succumb to embryonic death at midgestation due to insufficient sprouting and remodeling of the primary capillary plexus. To identify the underlying genetic mechanisms regulating the process of vascular remodeling, transcriptomes modulated by Tie2 signaling were analyzed utilizing serial analysis of gene expression (SAGE). Two libraries were constructed and sequenced using embryonic day 8.5 yolk sac tissues from Tie2 wild-type and the Tie2-null littermates. After tag extraction, 45,689 and 45,275 SAGE tags were obtained for the Tie2 wild-type and Tie2-null libraries, respectively, yielding a total of 21,376 distinct tags. Close to 62% of the tags were uniquely annotated, whereas 10% of the total tags were unknown. Using semiquantitative PCR, the differential expression of eight genes was confirmed that included Elk3, an important angiogenic switch gene which was upregulated in the absence of Tie2 signaling. The results of this study provide valuable insight into the potential association between Tie2 signaling and other known angiogenic pathways as well as genes that might have novel functions in vascular remodeling.
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Affiliation(s)
- Stephen H Chen
- Division of Molecular and Cellular Biology Research, Sunnybrook and Women's Research Institute, Toronto, Ontario, Canada
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