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Cebeci Z, Kir N. Role of implants in the treatment of diabetic macular edema: focus on the dexamethasone intravitreal implant. Diabetes Metab Syndr Obes 2015; 8:555-66. [PMID: 26604809 PMCID: PMC4655951 DOI: 10.2147/dmso.s73540] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Diabetic macular edema (DME) is the leading cause of sight-threatening complication in diabetic patients, and several treatment modalities have been developed and evaluated to treat this pathology. Intravitreal agents, such as anti-vascular endothelial growth factors (anti-VEGF) or corticosteroids, have become more popular in recent years and are widely used for treating DME. Sustained release drugs appear to be mentioned more often nowadays for extending the period of intravitreal activity, and corticosteroids play a key role in inhibiting the inflammatory process in DME. A potent corticosteroid, dexamethasone (Ozurdex(®)), in the form of an intravitreal implant, has been approved for various ocular etiologies among which DME is also one. This review evaluates the role of implants in the treatment of DME, mainly focusing on the dexamethasone intravitreal implant.
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Affiliation(s)
- Zafer Cebeci
- Department of Ophthalmology, Istanbul Faculty of Medicine, Istanbul University, Capa, Istanbul, Turkey
- Correspondence: Zafer Cebeci, Department of Ophthalmology, Istanbul Faculty of Medicine, Istanbul University, Capa 34390, Istanbul, Turkey, Tel +90 212 414 2000, Fax +90 212 414 2026, Email
| | - Nur Kir
- Department of Ophthalmology, Istanbul Faculty of Medicine, Istanbul University, Capa, Istanbul, Turkey
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Wang Q, Bozack SN, Yan Y, Boulton ME, Grant MB, Busik JV. Regulation of retinal inflammation by rhythmic expression of MiR-146a in diabetic retina. Invest Ophthalmol Vis Sci 2014; 55:3986-94. [PMID: 24867582 DOI: 10.1167/iovs.13-13076] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Chronic inflammation and dysregulation of circadian rhythmicity are involved in the pathogenesis of diabetic retinopathy. MicroRNAs (miRNAs) can regulate inflammation and circadian clock machinery. We tested the hypothesis that altered daily rhythm of miR-146a expression in diabetes contributes to retinal inflammation. METHODS Nondiabetic and STZ-induced diabetic rats kept in 12/12 light/dark cycle were killed every 2 hours over a 72-hour period. Human retinal endothelial cells (HRECs) were synchronized with dexamethasone. Expression of miR-146a, IL-1 receptor-associated kinase 1 (IRAK1), IL-1β, VEGF and ICAM-1, as well as clock genes was examined by real-time PCR and Western blot. To modulate expression levels of miR-146a, mimics and inhibitors were used. RESULTS Diabetes inhibited amplitude of negative arm (per1) and enhanced amplitude of the positive arm (bmal1) of clock machinery in retina. In addition to clock genes, miR-146a and its target gene IRAK1 also exhibited daily oscillations in antiphase; however, these patterns were lost in diabetic retina. This loss of rhythmic pattern was associated with an increase in ICAM-1, IL-β, and VEGF expression. Human retinal endothelial cells had robust miR-146a expression that followed circadian oscillation pattern; however, HRECs isolated from diabetic donors had reduced miR-146a amplitude but increased amplitude of IRAK1 and ICAM-1. In HRECs, miR-146a mimic or inhibitor caused 1.6- and 1.7-fold decrease or 1.5- and 1.6-fold increase, respectively, in mRNA and protein expression levels of ICAM-1 after 48 hours. CONCLUSIONS Diabetes-induced dysregulation of daily rhythms of miR-146a and inflammatory pathways under miR-146a control have potential implications for the development of diabetic retinopathy.
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Affiliation(s)
- Qi Wang
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States
| | - Svetlana N Bozack
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States
| | - Yuanqing Yan
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States
| | - Michael E Boulton
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Maria B Grant
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida, United States Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Julia V Busik
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States
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Abstract
Hyperglycemia has toxic effects on almost all cells in the body. Ophthalmic complications of hyperglycemia are most profound in cornea and retina. Seventy percent of diabetics suffer from corneal complications, collectively called diabetic keratopathy, which includes include recurrent erosions, delayed wound healing, ulcers, and edema. Confocal microscopy has permitted in vivo imaging of corneal nerves, which are also affected in diabetic subjects. Gene therapies upregulating MNNG HOS transforming gene (cMet) and/or downregulating MMP10 and cathepsin S are potential future therapies for diabetic keratopathy. Diabetic retinopathy (DR) is the most common cause of blindness in people over the age of 50. There is accumulating evidence that DR is an inflammatory disease. The initial events in animal models of DR are increased vascular permeability and leukostasis. This binding of leukocytes to the endothelium results from an increase in intracellular adhesion molecule-1 (ICAM-1) on the retinal capillary endothelium (EC) and expression of CD11/CD18 on the surface of the activated leukocyte. We have observed polymorphonuclear leukocytes (PMNs) at sites of EC vascular dysfunction in diabetic retinas as well as choroid. Anti-inflammatory drugs like etanercept, aspirin, or meloxicam reduce leukostasis and EC death. Future therapies may include repopulation of the acellular capillaries after EC and pericyte death with vascular progenitors made from the patient's own blood cells.
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Affiliation(s)
- Gerard A Lutty
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, Maryland
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Tsujikawa A, Ogura Y. Evaluation of Leukocyte-Endothelial Interactions in Retinal Diseases. Ophthalmologica 2012; 227:68-79. [DOI: 10.1159/000332080] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 08/23/2011] [Indexed: 11/19/2022]
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Opreanu M, Tikhonenko M, Bozack S, Lydic TA, Reid GE, McSorley KM, Sochacki A, Perez GI, Esselman WJ, Kern T, Kolesnick R, Grant MB, Busik JV. The unconventional role of acid sphingomyelinase in regulation of retinal microangiopathy in diabetic human and animal models. Diabetes 2011; 60:2370-8. [PMID: 21771974 PMCID: PMC3161322 DOI: 10.2337/db10-0550] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Acid sphingomyelinase (ASM) is an important early responder in inflammatory cytokine signaling. The role of ASM in retinal vascular inflammation and vessel loss associated with diabetic retinopathy is not known and represents the goal of this study. RESEARCH DESIGN AND METHODS Protein and gene expression profiles were determined by quantitative RT-PCR and Western blot. ASM activity was determined using Amplex Red sphingomyelinase assay. Caveolar lipid composition was analyzed by nano-electrospray ionization tandem mass spectrometry. Streptozotocin-induced diabetes and retinal ischemia-reperfusion models were used in in vivo studies. RESULTS We identify endothelial caveolae-associated ASM as an essential component in mediating inflammation and vascular pathology in in vivo and in vitro models of diabetic retinopathy. Human retinal endothelial cells (HREC), in contrast with glial and epithelial cells, express the plasma membrane form of ASM that overlaps with caveolin-1. Treatment of HREC with docosahexaenoic acid (DHA) specifically reduces expression of the caveolae-associated ASM, prevents a tumor necrosis factor-α-induced increase in the ceramide-to-sphingomyelin ratio in the caveolae, and inhibits cytokine-induced inflammatory signaling. ASM is expressed in both vascular and neuroretina; however, only vascular ASM is specifically increased in the retinas of animal models at the vasodegenerative phase of diabetic retinopathy. The absence of ASM in ASM(-/-) mice or inhibition of ASM activity by DHA prevents acellular capillary formation. CONCLUSIONS This is the first study demonstrating activation of ASM in the retinal vasculature of diabetic retinopathy animal models. Inhibition of ASM could be further explored as a potential therapeutic strategy in treating diabetic retinopathy.
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Affiliation(s)
- Madalina Opreanu
- Department of Physiology, Michigan State University, East Lansing, Michigan
- Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Maria Tikhonenko
- Department of Physiology, Michigan State University, East Lansing, Michigan
| | - Svetlana Bozack
- Department of Physiology, Michigan State University, East Lansing, Michigan
- Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Todd A. Lydic
- Department of Physiology, Michigan State University, East Lansing, Michigan
- Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Gavin E. Reid
- Chemistry and Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan
| | - Kelly M. McSorley
- Department of Physiology, Michigan State University, East Lansing, Michigan
| | - Andrew Sochacki
- Department of Physiology, Michigan State University, East Lansing, Michigan
| | - Gloria I. Perez
- Department of Physiology, Michigan State University, East Lansing, Michigan
| | - Walter J. Esselman
- Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Timothy Kern
- Department of Medicine, Division of Endocrinology, Case Western Reserve University, Cleveland, Ohio
| | - Richard Kolesnick
- Department of Molecular Pharmacology and Chemistry, Sloan-Kettering Institute, New York, New York
| | - Maria B. Grant
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida
| | - Julia V. Busik
- Department of Physiology, Michigan State University, East Lansing, Michigan
- Corresponding author: Julia V. Busik,
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Tikhonenko M, Lydic TA, Wang Y, Chen W, Opreanu M, Sochacki A, McSorley KM, Renis RL, Kern T, Jump DB, Reid GE, Busik JV. Remodeling of retinal Fatty acids in an animal model of diabetes: a decrease in long-chain polyunsaturated fatty acids is associated with a decrease in fatty acid elongases Elovl2 and Elovl4. Diabetes 2010; 59:219-27. [PMID: 19875612 PMCID: PMC2797925 DOI: 10.2337/db09-0728] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The results of the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications cohort study revealed a strong association between dyslipidemia and the development of diabetic retinopathy. However, there are no experimental data on retinal fatty acid metabolism in diabetes. This study determined retinal-specific fatty acid metabolism in control and diabetic animals. RESEARCH DESIGN AND METHODS Tissue gene and protein expression profiles were determined by quantitative RT-PCR and Western blot in control and streptozotocin-induced diabetic rats at 3-6 weeks of diabetes. Fatty acid profiles were assessed by reverse-phase high-performance liquid chromatography, and phospholipid analysis was performed by nano-electrospray ionization tandem mass spectrometry. RESULTS We found a dramatic difference between retinal and liver elongase and desaturase profiles with high elongase and low desaturase gene expression in the retina compared with liver. Elovl4, an elongase expressed in the retina but not in the liver, showed the greatest expression level among retinal elongases, followed by Elovl2, Elovl1, and Elovl6. Importantly, early-stage diabetes induced a marked decrease in retinal expression levels of Elovl4, Elovl2, and Elovl6. Diabetes-induced downregulation of retinal elongases translated into a significant decrease in total retinal docosahexaenoic acid, as well as decreased incorporation of very-long-chain polyunsaturated fatty acids (PUFAs), particularly 32:6n3, into retinal phosphatidylcholine. This decrease in n3 PUFAs was coupled with inflammatory status in diabetic retina, reflected by an increase in gene expression of proinflammatory markers interleukin-6, vascular endothelial growth factor, and intercellular adhesion molecule-1. CONCLUSIONS This is the first comprehensive study demonstrating diabetes-induced changes in retinal fatty acid metabolism. Normalization of retinal fatty acid levels by dietary means or/and modulating expression of elongases could represent a potential therapeutic target for diabetes-induced retinal inflammation.
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Affiliation(s)
- Maria Tikhonenko
- Department of Physiology, Michigan State University, East Lansing, Michigan
| | - Todd A. Lydic
- Department of Physiology, Michigan State University, East Lansing, Michigan
| | | | - Weiqin Chen
- Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Madalina Opreanu
- Department of Physiology, Michigan State University, East Lansing, Michigan
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Andrew Sochacki
- Department of Physiology, Michigan State University, East Lansing, Michigan
| | - Kelly M. McSorley
- Department of Physiology, Michigan State University, East Lansing, Michigan
| | - Rebecca L. Renis
- Department of Chemistry, Michigan State University, East Lansing, Michigan
| | - Timothy Kern
- Department of Medicine, Division of Endocrinology, Case Western Reserve University, Cleveland, Ohio
| | - Donald B. Jump
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon
| | - Gavin E. Reid
- Department of Chemistry, Michigan State University, East Lansing, Michigan
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan
| | - Julia V. Busik
- Department of Physiology, Michigan State University, East Lansing, Michigan
- Corresponding author: Julia V. Busik,
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Suppressive effect of short-interfering RNA on hyperglycemia-induced expression of intercellular adhesion molecule-1 on cultured vascular endothelial cells. Graefes Arch Clin Exp Ophthalmol 2008; 246:989-92. [PMID: 18365231 DOI: 10.1007/s00417-008-0794-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 02/05/2008] [Accepted: 02/19/2008] [Indexed: 10/22/2022] Open
Abstract
PURPOSE The pathology of diabetic retinopathy involves endothelial dysfunction, in which leukocyte adhesion to the vascular endothelium via intercellular adhesion molecule-1 (ICAM-1) may play a key role. Short-interfering RNAs (siRNAs) are unique modulators of gene expression in mammalian cells. The purpose of this study was to evaluate the enhanced effect of hyperglycemia and the attenuating effect of siRNAs on ICAM-1 expression in cultured endothelial cells. METHODS Human umbilical vein endothelial cells (HUVECs) were seeded onto 24-well culture plates. The following day, ICAM-1-specific siRNAs were transfected using Lipofectamine 2000. Glucose (15, 30, or 45 mM) or interleukin-1ss as a positive control was added to the medium to stimulate ICAM-1. After 48 hours, the HUVECs were collected to measure the ICAM-1 expression by enzyme-linked immunosolvent assay. Fluoresceinated siRNAs were transfected into HUVECs to confirm transfection of the siRNAs into HUVECs by fluorescein microscopy. RESULTS Glucose enhanced the ICAM-1 expression in a dose-dependent manner. ICAM-1 expression stimulated by hyperglycemia decreased significantly in the HUVECs transfected with corresponding siRNAs. Transfection of siRNAs was confirmed with enhanced fluorescence in HUVECs incubated with control siRNAs. CONCLUSIONS These results suggested that hyperglycemia stimulated protein expression of ICAM-1 and that siRNAs suppressed gene expression of ICAM-1 in HUVECs. The RNA-targeting approach using siRNAs may provide a novel therapeutic option for diabetic retinopathy.
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Hirata F, Yoshida M, Ogura Y. High glucose exacerbates neutrophil adhesion to human retinal endothelial cells. Exp Eye Res 2006; 82:179-82. [PMID: 16202408 DOI: 10.1016/j.exer.2005.08.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2005] [Revised: 07/26/2005] [Accepted: 08/26/2005] [Indexed: 11/25/2022]
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