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Munk MR, Somfai GM, de Smet MD, Donati G, Menke MN, Garweg JG, Ceklic L. The Role of Intravitreal Corticosteroids in the Treatment of DME: Predictive OCT Biomarkers. Int J Mol Sci 2022; 23:ijms23147585. [PMID: 35886930 PMCID: PMC9319632 DOI: 10.3390/ijms23147585] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 11/18/2022] Open
Abstract
This work aims to summarize predictive biomarkers to guide treatment choice in DME. Intravitreal anti-VEGF is considered the gold standard treatment for centers involving DME, while intravitreal steroid treatment has been established as a second-line treatment in DME. However, more than 1/3 of the patients do not adequately respond to anti-VEGF treatment despite up to 4-weekly injections. Not surprisingly, insufficient response to anti-VEGF therapy has been linked to low-normal VEGF levels in the serum and aqueous humor. These patients may well benefit from an early switch to intravitreal steroid treatment. In these patients, morphological biomarkers visible in OCT may predict treatment response and guide treatment decisions. Namely, the presence of a large amount of retinal and choroidal hyperreflective foci, disruption of the outer retinal layers and other signs of chronicity such as intraretinal cysts extending into the outer retina and a lower choroidal vascular index are all signs suggestive of a favorable treatment response of steroids compared to anti-VEGF. This paper summarizes predictive biomarkers in DME in order to assist individual treatment decisions in DME. These markers will help to identify DME patients who may benefit from primary dexamethasone treatment or an early switch.
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Affiliation(s)
- Marion R. Munk
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland;
- Bern Photographic Reading Center, Inselspital, University Hospital Bern, 3010 Bern, Switzerland
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60208, USA
- Correspondence: ; Tel.: +41-31-632-25-01
| | - Gabor Mark Somfai
- Department of Ophthalmology, Stadtspital Zürich, 8063 Zurich, Switzerland;
- Spross Research Institute, 8063 Zurich, Switzerland
- Department of Ophthalmology, Faculty of Medicine, Semmelweis University, 1085 Budapest, Hungary
| | - Marc D. de Smet
- Medical/Surgical Retina and Ocular Inflammation, University of Lausanne, MIOS SA, 1015 Lausanne, Switzerland;
| | - Guy Donati
- Centre Ophtalmologique de la Colline, University of Geneve, 1205 Geneve, Switzerland;
| | - Marcel N. Menke
- Department of Ophthalmology, Cantonal Hospital Aarau, 5001 Aarau, Switzerland;
| | - Justus G. Garweg
- Swiss Eye Institute, Berner Augenklinik am Lindenhofspital, 3012 Bern, Switzerland;
| | - Lala Ceklic
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland;
- Bern Photographic Reading Center, Inselspital, University Hospital Bern, 3010 Bern, Switzerland
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Huang J, Zhou Q. CD8+T Cell-Related Gene Biomarkers in Macular Edema of Diabetic Retinopathy. Front Endocrinol (Lausanne) 2022; 13:907396. [PMID: 35937822 PMCID: PMC9355330 DOI: 10.3389/fendo.2022.907396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/22/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND CD8+T lymphocytes have a strong pro-inflammatory effect in all parts of the tissue, and some studies have demonstrated that its concentration in the vitreous increased significantly, suggesting that CD8+T cells play a pivotal role in the inflammatory response of diabetic retinopathy (DR). However, the infiltration of CD8+T cells in the DR retina, especially in diabetic macular edema (DME), and its related genes are still unclear. METHODS Download the GSE16036 dataset from the Gene Expression Omnibus (GEO) database. The ImmuCellAI program was performed to evaluate the abundance of 24 immune cells including CD8+T cells. The CD8+T cell-related genes (DECD8+TRGs) between non-proliferative diabetic retinopathy (NPDR) and DME were detected via difference analysis and correlation analysis. Enrichment analysis and protein-protein interaction (PPI) network mapping were implemented to explore the potential function of DECD8+TRGs. Lasso regression, support vector machine recursive feature elimination (SVM-RFE), CytoHubba plug-in and MCODE plug-in in Cytoscape software, and Weighted Gene Co-Expression Network Analysis (WGCNA) were performed to comprehensively analyze and obtain Hub DECD8+TRGs. Hub DECD8+TRGs expression patterns were further validated in other two DR-related independent datasets. The CD8+TRG score was defined as the genetic characterization of Hub DECD8+TRGs using the GSVA sample scoring method, which can be administered to distinguish early and advanced diabetic nephropathy (DN) as well as normal and DN. Finally, the transcription level of DECD8+TRGs in DR model mouse were verified by quantitative real-time PCR (qPCR). RESULTS A total of 371 DECD8+TRGs were identified, of which 294 genes were positively correlated and only 77 genes were negatively correlated. Eight genes (IKZF1, PTPRC, ITGB2, ITGAX, TLR7, LYN, CD74, SPI1) were recognized as Hub DECD8+TRGs. DR and DN, which have strong clinical correlation, have been proved to be associated with CD8+T cell-related hub genes by multiple independent data sets. Hub DECD8+TRGs can not only distinguish PDR from normal and DN from normal, but also play a role in the early and progressive stages of the two diseases (NPDR vs DME, Early DN vs Advanced DN). The qPCR transcription level and trend of Hub DECD8+TRGs in DR mouse model was basically the same as that in human transcriptome. CONCLUSION This study not only increases our understanding of the molecular mechanism of CD8+T cells in the progression of DME, but also expands people's cognitive vision of the molecular mechanism of crosstalk of CD8+T cells in the eyes and kidneys of patients with diabetes.
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Szymanska M, Mahmood D, Yap TE, Cordeiro MF. Recent Advancements in the Medical Treatment of Diabetic Retinal Disease. Int J Mol Sci 2021; 22:ijms22179441. [PMID: 34502350 PMCID: PMC8430918 DOI: 10.3390/ijms22179441] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 02/06/2023] Open
Abstract
Diabetic retinal disease remains one of the most common complications of diabetes mellitus (DM) and a leading cause of preventable blindness. The mainstay of management involves glycemic control, intravitreal, and laser therapy. However, intravitreal therapy commonly requires frequent hospital visits and some patients fail to achieve a significant improvement in vision. Novel and long-acting therapies targeting a range of pathways are warranted, while evidence to support optimal combinations of treatments is currently insufficient. Improved understanding of the molecular pathways involved in pathogenesis is driving the development of therapeutic agents not only targeting visible microvascular disease and metabolic derangements, but also inflammation and accelerated retinal neurodegeneration. This review summarizes the current and emerging treatments of diabetic retinal diseases and provides an insight into the future of managing this important condition.
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Affiliation(s)
- Maja Szymanska
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London NW1 5QH, UK; (M.S.); (D.M.); (T.E.Y.)
| | - Daanyaal Mahmood
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London NW1 5QH, UK; (M.S.); (D.M.); (T.E.Y.)
| | - Timothy E. Yap
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London NW1 5QH, UK; (M.S.); (D.M.); (T.E.Y.)
| | - Maria F. Cordeiro
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London, London NW1 5QH, UK; (M.S.); (D.M.); (T.E.Y.)
- The Western Eye Hospital, Imperial College Healthcare NHS Trust (ICHNT), London NW1 5QH, UK
- Glaucoma and Retinal Neurodegeneration Group, Department of Visual Neuroscience, UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Correspondence:
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Feizi S, Alemzadeh-Ansari M, Karimian F, Esfandiari H. Use of erythropoietin in ophthalmology: a review. Surv Ophthalmol 2021; 67:427-439. [PMID: 34157346 DOI: 10.1016/j.survophthal.2021.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 06/08/2021] [Accepted: 06/14/2021] [Indexed: 12/17/2022]
Abstract
Erythropoietin (EPO) is a glycoprotein hormone that regulates hematopoiesis in the human body. The presence of EPO and its receptors in different tissues indicates that this hormone has extramedullary effects in other tissues, including the eye. We focus on the biological roles of this hormone in the development and normal physiologic functions of the eye. Furthermore, we explore the role of EPO in the management of different ocular diseases - including diabetic retinopathy, retinopathy of prematurity, inherited retinal degeneration, branch and central retinal vein occlusion, retinal detachment, traumatic optic neuropathy, optic neuritis, methanol optic neuropathy, nonarteritic anterior ischemic optic neuropathy, glaucoma, and scleral necrosis.
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Affiliation(s)
- Sepehr Feizi
- Ophthalmic Research Center, Department of Ophthalmology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | | | - Farid Karimian
- Ophthalmic Research Center, Department of Ophthalmology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamed Esfandiari
- Department of Ophthalmology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
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Lin J, Hu J, Schlotterer A, Wang J, Kolibabka M, Awwad K, Dietrich N, Breitschopf K, Wohlfart P, Kannt A, Lorenz K, Feng Y, Popp R, Hoffmann S, Fleming I, Hammes HP. Protective effect of Soluble Epoxide Hydrolase Inhibition in Retinal Vasculopathy associated with Polycystic Kidney Disease. Am J Cancer Res 2020; 10:7857-7871. [PMID: 32685025 PMCID: PMC7359083 DOI: 10.7150/thno.43154] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 05/20/2020] [Indexed: 12/14/2022] Open
Abstract
Rationale: Vasoregression secondary to glial activation develops in various retinal diseases, including retinal degeneration and diabetic retinopathy. Photoreceptor degeneration and subsequent retinal vasoregression, characterized by pericyte loss and acellular capillary formation in the absence diabetes, are also seen in transgenic rats expressing the polycystic kidney disease (PKD) gene. Activated Müller glia contributes to retinal vasodegeneration, at least in part via the expression of the soluble epoxide hydrolase (sEH). Given that an increase in sEH expression triggered vascular destabilization in diabetes, and that vasoregression is similar in diabetic mice and PKD rats, the aim of the present study was to determine whether sEH inhibition could prevent retinal vasoregression in the PKD rat. Methods: One-month old male homozygous transgenic PKD rats were randomly allocated to receive vehicle or a sEH inhibitor (sEH-I; Sar5399, 30 mg/kg) for four weeks. Wild-type Sprague-Dawley (SD) littermates received vehicle as controls. Retinal sEH expression and activity were measured by Western blotting and LC-MS, and vasoregression was quantified in retinal digestion preparations. Microglial activation and immune response cytokines were assessed by immunofluorescence and quantitative PCR, respectively. 19,20-dihydroxydocosapentaenoic acid (19,20-DHDP) mediated Notch signaling, microglial activation and migration were assessed in vivo and in vitro. Results: This study demonstrates that sEH expression and activity were increased in PKD retinae, which led to elevated production of 19,20-DHDP and the depression of Notch signaling. The latter changes elicited pericyte loss and the recruitment of CD11b+/CD74+ microglia to the perivascular region. Microglial activation increased the expression of immune-response cytokines, and reduced levels of Notch3 and delta-like ligand 4 (Dll4). Treatment with Sar5399 decreased 19,20-DHDP generation and increased Notch3 expression. Sar5399 also prevented vasoregression by reducing pericyte loss and suppressed microglial activation as well as the expression of immune-response cytokines. Mechanistically, the activation of Notch signaling by Dll4 maintained a quiescent microglial cell phenotype, i.e. reduced both the surface presentation of CD74 and microglial migration. In contrast, in retinal explants, 19,20-DHDP and Notch inhibition both promoted CD74 expression and reversed the Dll4-induced decrease in migration. Conclusions: Our data indicate that 19,20-DHDP-induced alterations in Notch-signaling result in microglia activation and pericyte loss and contribute to retinal vasoregression in polycystic kidney disease. Moreover, sEH inhibition can ameliorate vasoregression through reduced activity of inflammatory microglia. sEH inhibition is thus an attractive new therapeutic approach to prevent retinal vasoregression.
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Rossino MG, Dal Monte M, Casini G. Relationships Between Neurodegeneration and Vascular Damage in Diabetic Retinopathy. Front Neurosci 2019; 13:1172. [PMID: 31787868 PMCID: PMC6856056 DOI: 10.3389/fnins.2019.01172] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/16/2019] [Indexed: 12/15/2022] Open
Abstract
Diabetic retinopathy (DR) is a common complication of diabetes and constitutes a major cause of vision impairment and blindness in the world. DR has long been described exclusively as a microvascular disease of the eye. However, in recent years, a growing interest has been focused on the contribution of neuroretinal degeneration to the pathogenesis of the disease, and there are observations suggesting that neuronal death in the early phases of DR may favor the development of microvascular abnormalities, followed by the full manifestation of the disease. However, the mediators that are involved in the crosslink between neurodegeneration and vascular changes have not yet been identified. According to our hypothesis, vascular endothelial growth factor (VEGF) could probably be the most important connecting link between the death of retinal neurons and the occurrence of microvascular lesions. Indeed, VEGF is known to play important neuroprotective actions; therefore, in the early phases of DR, it may be released in response to neuronal suffering, and it would act as a double-edged weapon inducing both neuroprotective and vasoactive effects. If this hypothesis is correct, then any retinal stress causing neuronal damage should be accompanied by VEGF upregulation and by vascular changes. Similarly, any compound with neuroprotective properties should also induce VEGF downregulation and amelioration of the vascular lesions. In this review, we searched for a correlation between neurodegeneration and vasculopathy in animal models of retinal diseases, examining the effects of different neuroprotective substances, ranging from nutraceuticals to antioxidants to neuropeptides and others and showing that reducing neuronal suffering also prevents overexpression of VEGF and vascular complications. Taken together, the reviewed evidence highlights the crucial role played by mediators such as VEGF in the relationship between retinal neuronal damage and vascular alterations and suggests that the use of neuroprotective substances could be an efficient strategy to prevent the onset or to retard the development of DR.
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Affiliation(s)
| | - Massimo Dal Monte
- Department of Biology, University of Pisa, Pisa, Italy.,Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy
| | - Giovanni Casini
- Department of Biology, University of Pisa, Pisa, Italy.,Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy
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Abstract
PURPOSE OF REVIEW Diabetic retinopathy (DR) is the leading cause of acquired vision loss in adults across the globe. Early identification and treatment of patients with DR is paramount for vision preservation. The aim of this review paper is to outline current and new imaging techniques and biomarkers that are valuable for clinical diagnosis and management of DR. RECENT FINDINGS Ultrawide field imaging and automated deep learning algorithms are recent advancements on traditional fundus photography and fluorescein angiography. Optical coherence tomography (OCT) and OCT angiography are techniques that image retinal anatomy and vasculature and OCT is routinely used to monitor response to treatment. Many circulating, vitreous, and genetic biomarkers have been studied to facilitate disease detection and development of new treatments. Recent advancements in retinal imaging and identification of promising new biomarkers for DR have the potential to increase detection, risk stratification, and treatment for patients with DR.
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Affiliation(s)
- Changyow C Kwan
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Avenue, Suite 440, Chicago, IL, 60611, USA
| | - Amani A Fawzi
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Avenue, Suite 440, Chicago, IL, 60611, USA.
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8
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Kern TS, Antonetti DA, Smith LEH. Pathophysiology of Diabetic Retinopathy: Contribution and Limitations of Laboratory Research. Ophthalmic Res 2019; 62:196-202. [PMID: 31362288 PMCID: PMC6872907 DOI: 10.1159/000500026] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 03/29/2019] [Indexed: 12/11/2022]
Abstract
Preclinical models of diabetic retinopathy are indispensable in the drug discovery and development of new therapies. They are, however, imperfect facsimiles of diabetic retinopathy in humans. This chapter discusses the advantages, limitations, and physiological and pathological relevance of preclinical models of diabetic retinopathy. The judicious interpretation and extrapolation of data derived from these models to humans and a correspondingly greater emphasis placed on translational medical research in early-stage clinical trials are essential to more successfully inhibit the development and progression of diabetic retinopathy in the future.
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Affiliation(s)
- Timothy S Kern
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA,
- Veterans Administration Medical Center Research Service 151, Cleveland, Ohio, USA,
| | - David A Antonetti
- Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Lois E H Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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9
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Chakravarthy H, Devanathan V. Molecular Mechanisms Mediating Diabetic Retinal Neurodegeneration: Potential Research Avenues and Therapeutic Targets. J Mol Neurosci 2018; 66:445-461. [PMID: 30293228 DOI: 10.1007/s12031-018-1188-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 09/25/2018] [Indexed: 12/16/2022]
Abstract
Diabetic retinopathy (DR) is a devastating complication of diabetes with a prevalence rate of 35%, and no effective treatment options. Since the most visible clinical features of DR are microvascular irregularities, therapeutic interventions often attempt to reduce microvascular injury, but only after permanent retinal damage has ensued. However, recent data suggests that diabetes initially affects retinal neurons, leading to neurodegeneration as an early occurrence in DR, before onset of the more noticeable vascular abnormalities. In this review, we delineate the sequence of initiating events leading to retinal degeneration in DR, considering neuronal dysfunction as a primary event. Key molecular mechanisms and potential biomarkers associated with retinal neuronal degeneration in diabetes are discussed. In addition to glial reactivity and inflammation in the diabetic retina, the contribution of neurotrophic factors, cell adhesion molecules, apoptosis markers, and G protein signaling to neurodegenerative pathways warrants further investigation. These studies could complement recent developments in innovative treatment strategies for diabetic retinopathy, such as targeting retinal neuroprotection, promoting neuronal regeneration, and attempts to re-program other retinal cell types into functional neurons. Indeed, several ongoing clinical trials are currently attempting treatment of retinal neurodegeneration by means of such novel therapeutic avenues. The aim of this article is to highlight the crucial role of neurodegeneration in early retinopathy progression, and to review the molecular basis of neuronal dysfunction as a first step toward developing early therapeutic interventions that can prevent permanent retinal damage in diabetes. ClinicalTrials.gov: NCT02471651, NCT01492400.
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Affiliation(s)
- Harshini Chakravarthy
- Department of Biology, Indian Institute of Science Education and Research (IISER), Transit campus: C/o. Sree Rama Engineering College Campus, Karakambadi Road, Mangalam, Tirupati, 517507, India
| | - Vasudharani Devanathan
- Department of Biology, Indian Institute of Science Education and Research (IISER), Transit campus: C/o. Sree Rama Engineering College Campus, Karakambadi Road, Mangalam, Tirupati, 517507, India.
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10
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Hammes HP. Diabetic retinopathy: hyperglycaemia, oxidative stress and beyond. Diabetologia 2018; 61:29-38. [PMID: 28942458 DOI: 10.1007/s00125-017-4435-8] [Citation(s) in RCA: 204] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 07/04/2017] [Indexed: 12/15/2022]
Abstract
Diabetic retinopathy remains a relevant clinical problem. In parallel with diagnostic and therapeutic improvements, the role of glycaemia and reactive metabolites causing cell stress and biochemical abnormalities as treatment targets needs continuous re-evaluation. Furthermore, the basic mechanisms of physiological angiogenesis, remodelling and pruning give important clues about the origins of vasoregression during the very early stages of diabetic retinopathy and can be modelled in animals. This review summarises evidence supporting a role for the neurovascular unit-composed of neuronal, glial and vascular cells-as a responder to the biochemical changes imposed by reactive metabolites and high glucose. Normoglycaemic animal models developing retinal degeneration, provide valuable information about common pathways downstream of progressive neuronal damage that induce vasoregression, as in diabetic models. These models can serve to assess novel treatments addressing the entire neurovascular unit for the benefit of early diabetic retinopathy.
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Affiliation(s)
- Hans-Peter Hammes
- 5. Med. Department, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167, Mannheim, Germany.
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11
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Tsompos C, Panoulis C, Toutouzas K, Zografos G, Papalois A. THE ACUTE EFFECT OF ERYTHROPOIETIN ON GLUCOSE LEVELS DURING ISCHEMIA REPERFUSION INJURY IN RATS. FOLIA MEDICA INDONESIANA 2017. [DOI: 10.20473/fmi.v52i1.5199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of this experimental study was to examine the effect of erythropoietin on rat model and particularly in an ischemia reperfusion (HR) protocol. The effect of that molecule was studied biochemically using blood mean glucose (Gl) levels. Materials and methods: 40 rats of mean weight 247.7 g were used in the study. Gl levels were measured at 60 min (groups A and C) and at 120 min (groups B and D) of reperfusion. Erythropoietin was administered only in groups C and D. Results were that Epo administration non-significantly increased the gl levels by 5.59% +6.46% (p=0.3208). Reperfusion time non-significantly increased the gl levels by 5.63%+6.45% (p=0.4098). However, erythropoietin administration and reperfusion time together produced a non significant combined effect in increasing the gl levels by 4.94%+3.81% (p= 0.1892). Conclusions: Results of this study indicate that erythropoietin administration, reperfusion time, or their interaction non-significantly increase the blood glucose levels in short-term. Opposite bibliographic data are considered more reliable, until a greater sample provide clearer results.
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12
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Reid G, Lois N. Erythropoietin in diabetic retinopathy. Vision Res 2017; 139:237-242. [PMID: 28652140 DOI: 10.1016/j.visres.2017.05.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 05/21/2017] [Accepted: 05/24/2017] [Indexed: 12/19/2022]
Abstract
Over the past years, knowledge has expanded with regards to the multiple roles played by erythropoietin (EPO) in the body. Once believed to be a hormone synthesised in the kidney and involved only in the modulation of erythrocyte production, it is recognised now that EPO can be produced in many tissues, including the retina, and by many cells. In these tissues EPO is released in response to "tissue injury" and appears to have protective functions. Despite the extensive research conducted to date, the cues leading to release of EPO and its effects in the normal and diseased retina have not been fully elucidated. In vitro and in vivo experimental studies as well as small interventional clinical studies suggest a potential beneficial effect of externally administered EPO in early diabetic retinopathy and diabetic macular oedema. In contrast, controversy exists with regards to the possible use of EPO in proliferative diabetic retinopathy. Non-erythropoietic EPO-derived peptides, produced with the aim of increasing effectiveness and reducing side effects of EPO, are currently under investigation in early phase clinical trials.
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Affiliation(s)
- Gerard Reid
- Ophthalmology Department, Belfast Health and Social Care Trust, Royal Victoria Hospital, 274 Grosvenor Rd, Belfast BT12 6BA, UK
| | - Noemi Lois
- Ophthalmology Department, Belfast Health and Social Care Trust, Royal Victoria Hospital, 274 Grosvenor Rd, Belfast BT12 6BA, UK; Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, 97 Lisburn Road, BT9 7BL Belfast, UK.
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13
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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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14
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Iwona BS. Growth Factors in the Pathogenesis of Retinal Neurodegeneration in Diabetes Mellitus. Curr Neuropharmacol 2017; 14:792-804. [PMID: 27528260 PMCID: PMC5333593 DOI: 10.2174/1570159x14666160813182009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 11/12/2015] [Accepted: 01/06/2015] [Indexed: 12/13/2022] Open
Abstract
Neurodegeneration is an initial process in the development of diabetic retinopathy (DR). High quantities of glutamate, oxidative stress, induction of the renin-angiotensin system (RAS) and elevated levels of RAGE are crucial elements in the retinal neurodegeneration caused by diabetes mellitus. At least, there is emerging proof to indicate that the equilibrium between the neurotoxic and neuroprotective components will affect the state of the retinal neurons. Somatostatin (SST), pigment epithelium-derived factor (PEDF), and erythropoietin (Epo) are endogenous neuroprotective peptides that are decreased in the eye of diabetic persons and play an essential role in retinal homeostasis. On the other hand, insulin-like growth factor 1 (IGF-1), and vascular endothelial growth factor (VEGF) are pivotal proteins which participate in the development of new capillaries and finally cause damage to the retinal neurons. During recent years, our knowledge about the function of growth factors in the pathogenesis of retinal neurodegeneration has increased. However, intensive investigations are needed to clarify the basic processes that contribute to retinal neurodegeneration and its association with damage to the capillary blood vessels. The objective of this review article is to show new insights on the role of neurotransmitters and growth factors in the pathogenesis of diabetic retinopathy. The information contained in this manuscript may provide the basis for novel strategies based on the factors of neurodegeneration to diagnose, prevent and treat DR in its earliest phases.
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Affiliation(s)
- Ben-Skowronek Iwona
- Department Pediatric Endocrinology and Diabetology, Medical University of Lublin, ul. Prof. A. Gebali 6, 20-093 Lublin, Poland
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15
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Dietrich N, Kolibabka M, Busch S, Bugert P, Kaiser U, Lin J, Fleming T, Morcos M, Klein T, Schlotterer A, Hammes HP. The DPP4 Inhibitor Linagliptin Protects from Experimental Diabetic Retinopathy. PLoS One 2016; 11:e0167853. [PMID: 27942008 PMCID: PMC5152931 DOI: 10.1371/journal.pone.0167853] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/21/2016] [Indexed: 01/12/2023] Open
Abstract
Background/aims Dipeptidyl peptidase 4 (DPP4) inhibitors improve glycemic control in type 2 diabetes, however, their influence on the retinal neurovascular unit remains unclear. Methods Vasculo- and neuroprotective effects were assessed in experimental diabetic retinopathy and high glucose-cultivated C. elegans, respectively. In STZ-diabetic Wistar rats (diabetes duration of 24 weeks), DPP4 activity (fluorometric assay), GLP-1 (ELISA), methylglyoxal (LC-MS/MS), acellular capillaries and pericytes (quantitative retinal morphometry), SDF-1a and heme oxygenase-1 (ELISA), HMGB-1, Iba1 and Thy1.1 (immunohistochemistry), nuclei in the ganglion cell layer, GFAP (western blot), and IL-1beta, Icam1, Cxcr4, catalase and beta-actin (quantitative RT-PCR) were determined. In C. elegans, neuronal function was determined using worm tracking software. Results Linagliptin decreased DPP4 activity by 77% and resulted in an 11.5-fold increase in active GLP-1. Blood glucose and HbA1c were reduced by 13% and 14% and retinal methylglyoxal by 66%. The increase in acellular capillaries was diminished by 70% and linagliptin prevented the loss of pericytes and retinal ganglion cells. The rise in Iba-1 positive microglia was reduced by 73% with linagliptin. In addition, the increase in retinal Il1b expression was decreased by 65%. As a functional correlate, impairment of motility (body bending frequency) was significantly prevented in C. elegans. Conclusion Our data suggest that linagliptin has a protective effect on the microvasculature of the diabetic retina, most likely due to a combination of neuroprotective and antioxidative effects of linagliptin on the neurovascular unit.
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Affiliation(s)
- Nadine Dietrich
- 5th Medical Department, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Matthias Kolibabka
- 5th Medical Department, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Stephanie Busch
- 5th Medical Department, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Petra Bugert
- 5th Medical Department, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Ulrike Kaiser
- 5th Medical Department, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Jihong Lin
- 5th Medical Department, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Thomas Fleming
- Department of Medicine I, University of Heidelberg, Heidelberg, Germany
| | - Michael Morcos
- 5th Medical Department, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Thomas Klein
- Department of CardioMetabolic Diseases Research, Boehringer Ingelheim Pharma, Biberach, Germany
| | - Andrea Schlotterer
- 5th Medical Department, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Hans-Peter Hammes
- 5th Medical Department, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
- * E-mail:
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16
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Tsompos C, Panoulis C, Toutouzas K, Zografos G, Papalois A. The effect of erythropoietin on endometrial edema during ischemia–reperfusion injury in rats. J Histotechnol 2016. [DOI: 10.1080/01478885.2016.1202406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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17
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de Moraes G, Layton CJ. Therapeutic targeting of diabetic retinal neuropathy as a strategy in preventing diabetic retinopathy. Clin Exp Ophthalmol 2016; 44:838-852. [PMID: 27334889 DOI: 10.1111/ceo.12795] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/22/2016] [Accepted: 06/16/2016] [Indexed: 12/21/2022]
Abstract
Diabetes causes a panretinal neurodegeneration herein termed diabetic retinal neuropathy, which manifests in the retina early and progresses throughout the disease. Clinical manifestations include changes in the ERG, perimetry, dark adaptation, contrast sensitivity and colour vision which correlate with laboratory findings of thinning of the retinal neuronal layers, increased apoptosis in neurons and activation of glial cells. Possible mechanisms include oxidative stress, neuronal AGE accumulation, altered balance of neurotrophic factors and loss of mitohormesis. Retinal neural damage precedes and is a biologically plausible cause of retinal vasculopathy later in diabetes, and this review suggests that strategies to target it directly could prevent diabetes induced blindness. The efficacy of fenofibrate in reducing retinopathy progression provides a possible proof of concept for this approach. Strategies which may target diabetic retinal neuropathy include reducing retinal metabolic demand, improving mitochondrial function with AMPK and Sirt1 activators or providing neurotrophic support with neurotrophic supplementation.
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Affiliation(s)
| | - Christopher J Layton
- Gallipoli Medical Research Foundation, Brisbane, Queensland, Australia.,University of Queensland School of Medicine, Brisbane, Queensland, Australia.,Greenslopes Private Hospital Ophthalmology Department, Greenslopes Hospital, Brisbane, Queensland, Australia
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Li J, Wang P, Zhu Y, Chen Z, Shi T, Lei W, Yu S. Curcumin Inhibits Neuronal Loss in the Retina and Elevates Ca²⁺/Calmodulin-Dependent Protein Kinase II Activity in Diabetic Rats. J Ocul Pharmacol Ther 2015. [PMID: 26207889 DOI: 10.1089/jop.2015.0006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
PURPOSE To determine whether curcumin offers neuroprotection to minimize the apoptosis of neural cells in the retina of diabetic rats. METHODS Streptozotocin (STZ)-induced diabetic rats and control rats were used in this study. A subgroup of STZ-induced diabetic rats were treated with curcumin for 12 weeks. Retinal histology, apoptosis of neural cells in the retina, electroretinograms, and retinal glutamate content were evaluated after 12 weeks. Retinal levels of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), phospho-CaMKII (p-CaMKII), and cleaved caspase-3 were determined by Western blot analysis. RESULTS The amplitudes a-wave, b-wave, and oscillatory potential were reduced by diabetes, but curcumin treatment suppressed this reduction of amplitudes. Curcumin also prevented cell loss from the outer nuclear, inner nuclear, and ganglion cell layers. Apoptosis of retinal neurons was detected in diabetic rats. The concentration of glutamate in the retina was higher in diabetic rats, but was significantly reduced in the curcumin-treated group. Furthermore, p-CaMKII and cleaved caspase-3 expression were upregulated in the diabetic retina, but reduced in curcumin-treated rats. CONCLUSIONS Curcumin attenuated diabetes-induced apoptosis in retinal neurons by reducing the glutamate level and downregulating CaMKII. Thus, curcumin might be used to prevent neuronal damage in the retina of patients with diabetes mellitus.
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Affiliation(s)
- Jun Li
- Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China
| | - Peipei Wang
- Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China
| | - Yanxia Zhu
- Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China
| | - Zhen Chen
- Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China
| | - Tianyan Shi
- Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China
| | - Wensheng Lei
- Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China
| | - Songping Yu
- Department of Ophthalmology, Lishui Central Hospital and Fifth Affiliated Hospital of Wenzhou Medical University , Lishui, Zhejiang Province, People's Republic of China
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Chen LN, Sun Q, Liu SQ, Hu H, Lv J, Ji WJ, Wang M, Chen MX, Zhou J. Erythropoietin improves glucose metabolism and pancreatic β-cell damage in experimental diabetic rats. Mol Med Rep 2015; 12:5391-8. [PMID: 26126591 DOI: 10.3892/mmr.2015.4006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 06/03/2015] [Indexed: 11/05/2022] Open
Abstract
Previous studies have implicated erythropoietin (EPO) signaling in the regulation of glucose metabolism. Whether EPO can be used treat diabetes and the underlying mechanism remain to be elucidated. The present study aimed to investigate whether EPO affects glucose metabolism, and the underlying mechanisms, in experimental diabetic rats. The effects of EPO (300 U/kg three times a week for 4 weeks) on glucose metabolism, hematopoietic function, blood selenium content and the ultrastructure of pancreatic β‑cells were investigated in low dose (25 mg/kg body weight) streptozotocin‑induced experimental diabetic rats provided with a high‑fat diet. The results demonstrated that EPO significantly decreased the fasting blood glucose, the area under the curve of the oral glucose tolerance and insulin tolerance tests and L‑alanine gluconeogenesis. Ultrastructural examination of the pancreatic islets revealed that EPO prevented the dysfunction of pancreatic β‑cells in experimental diabetic rats, ameliorated cytoplasmic vacuolation and fragmentation of mitochondria, and increased the number of secretory granules. EPO administration increased the activities of superoxide dismutase and glutathione peroxidase, and decreased the level of malondialdehyde. Additionally, EPO increased blood selenium in the diabetic rats and produced a hematopoietic effect. These results indicated that EPO modulated glucose metabolism and improved pancreatic β‑cells damage by increasing anti‑oxidation. The detailed mechanisms underlying these effects require further investigation.
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Affiliation(s)
- Li-Na Chen
- Department of Pharmacology, School of Basic Medical Sciences, Xian Jiaotong University Health Science Center, Xian, Shaanxi 710061, P.R. China
| | - Qiang Sun
- Department of Pharmacology, School of Basic Medical Sciences, Xian Jiaotong University Health Science Center, Xian, Shaanxi 710061, P.R. China
| | - Shu-Qing Liu
- Department of Pharmacology, School of Basic Medical Sciences, Xian Jiaotong University Health Science Center, Xian, Shaanxi 710061, P.R. China
| | - Hao Hu
- Department of Pharmacology, School of Basic Medical Sciences, Xian Jiaotong University Health Science Center, Xian, Shaanxi 710061, P.R. China
| | - Juan Lv
- Department of Pharmacology, School of Basic Medical Sciences, Xian Jiaotong University Health Science Center, Xian, Shaanxi 710061, P.R. China
| | - Wen-Jun Ji
- Department of Pharmacology, School of Basic Medical Sciences, Xian Jiaotong University Health Science Center, Xian, Shaanxi 710061, P.R. China
| | - Meng Wang
- Department of Pharmacology, School of Basic Medical Sciences, Xian Jiaotong University Health Science Center, Xian, Shaanxi 710061, P.R. China
| | - Ming-Xia Chen
- Department of Electron Microscopy Room, School of Basic Medical Sciences, Xian Jiaotong University Health Science Center, Xian, Shaanxi 710061, P.R. China
| | - Jun Zhou
- Department of Pharmacology, School of Basic Medical Sciences, Xian Jiaotong University Health Science Center, Xian, Shaanxi 710061, P.R. China
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Angiopoietin-like 4 is a potent angiogenic factor and a novel therapeutic target for patients with proliferative diabetic retinopathy. Proc Natl Acad Sci U S A 2015; 112:E3030-9. [PMID: 26039997 PMCID: PMC4466723 DOI: 10.1073/pnas.1423765112] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In proliferative diabetic retinopathy (PDR), the most vision-threatening sequela of diabetic eye disease, retinal ischemia leads to increased expression of angiogenic factors that promote neovascularization. Although therapies targeting the potent angiogenic mediator vascular endothelial growth factor have been remarkably successful for the treatment of diabetic macular edema, this approach has not proven sufficient to prevent the development of retinal neovascularization, implicating additional angiogenic factor(s) in PDR pathogenesis. We demonstrate here that angiopoietin-like 4 is a potent angiogenic mediator with markedly increased expression in the eyes of PDR patients. Our studies identify a novel therapeutic target for the treatment of ocular neovascular disease and may have broad implications for the treatment of other diseases dependent on pathologic angiogenesis. Diabetic eye disease is the most common cause of severe vision loss in the working-age population in the developed world, and proliferative diabetic retinopathy (PDR) is its most vision-threatening sequela. In PDR, retinal ischemia leads to the up-regulation of angiogenic factors that promote neovascularization. Therapies targeting vascular endothelial growth factor (VEGF) delay the development of neovascularization in some, but not all, diabetic patients, implicating additional factor(s) in PDR pathogenesis. Here we demonstrate that the angiogenic potential of aqueous fluid from PDR patients is independent of VEGF concentration, providing an opportunity to evaluate the contribution of other angiogenic factor(s) to PDR development. We identify angiopoietin-like 4 (ANGPTL4) as a potent angiogenic factor whose expression is up-regulated in hypoxic retinal Müller cells in vitro and the ischemic retina in vivo. Expression of ANGPTL4 was increased in the aqueous and vitreous of PDR patients, independent of VEGF levels, correlated with the presence of diabetic eye disease, and localized to areas of retinal neovascularization. Inhibition of ANGPTL4 expression reduced the angiogenic potential of hypoxic Müller cells; this effect was additive with inhibition of VEGF expression. An ANGPTL4 neutralizing antibody inhibited the angiogenic effect of aqueous fluid from PDR patients, including samples from patients with low VEGF levels or receiving anti-VEGF therapy. Collectively, our results suggest that targeting both ANGPTL4 and VEGF may be necessary for effective treatment or prevention of PDR and provide the foundation for studies evaluating aqueous ANGPTL4 as a biomarker to help guide individualized therapy for diabetic eye disease.
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Simó R, Hernández C. Novel approaches for treating diabetic retinopathy based on recent pathogenic evidence. Prog Retin Eye Res 2015; 48:160-80. [PMID: 25936649 DOI: 10.1016/j.preteyeres.2015.04.003] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 04/13/2015] [Accepted: 04/21/2015] [Indexed: 12/15/2022]
Abstract
Diabetic retinopathy remains as a leading cause of blindness in developed countries. Current treatments target late stages of DR when vision has already been significantly affected. A better understanding of the pathogenesis of DR would permit the development of more efficient preventional/interventional strategies against early stages of DR. In this article a critical review of the state of the art of this issue is provided along with a discussion of problems which have yet to be overcome. Neuroprotection as a new approach for the treatment of the early stages of DR has been particularly emphasized. The development and progression of DR is not homogeneous and, apart from blood glucose levels and blood pressure, it depends on genetic factors which remain to be elucidated. In addition, the role of the pathogenic pathways is not the same in all patients. All these factors should be taken into account in the near future when an individualized oriented treatment for DR could become feasible. The new techniques in retinal imaging acquisition, the identification of useful circulating biomarkers and the individualized analysis of biological samples could facilitate the development of early and personalized therapy in the setting of DR. Finally, it should be noted that only a coordinated action among ophthalmologists, diabetologists, basic researchers, experts in pharmaco-economics and health care providers addressed to the design of rational strategies targeting prevention and the early stages of DR will be effective in reducing the burden and improving the clinical outcome of this devastating complication of diabetes.
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Affiliation(s)
- Rafael Simó
- CIBERDEM (CIBER de Diabetes y Enfermedades Metabólicas Asociadas) and Diabetes and Metabolism Research Unit, Vall Hebron Institut de Recerca (VHIR), Universitat Autónoma de Barcelona, 08035 Barcelona, Spain.
| | - Cristina Hernández
- CIBERDEM (CIBER de Diabetes y Enfermedades Metabólicas Asociadas) and Diabetes and Metabolism Research Unit, Vall Hebron Institut de Recerca (VHIR), Universitat Autónoma de Barcelona, 08035 Barcelona, Spain.
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22
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Ola MS, Alhomida AS. Neurodegeneration in diabetic retina and its potential drug targets. Curr Neuropharmacol 2014; 12:380-6. [PMID: 25342945 PMCID: PMC4207077 DOI: 10.2174/1570159x12666140619205024] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 04/27/2014] [Accepted: 06/19/2014] [Indexed: 12/04/2022] Open
Abstract
Diabetic retinopathy (DR) is one of the major complications of diabetes causing vision loss and blindness worldwide. DR is widely recognized as a neurodegenerative disease as evidenced from early changes at cellular and molecular levels in the neuronal component of the diabetic retina, which is further supported by various retinal functional tests indicating functional deficits in the retina soon after diabetes progression. Diabetes alters the level of a number of neurodegenerative metabolites, which increases influx through several metabolic pathways which in turn induce an increase in oxidative stress and a decrease in neurotrophic factors, thereby damage retinal neurons. Loss of neurons may implicate in vascular pathology, a clinical signs of DR observed at later stages of the disease. Here, we discuss diabetes-induced potential metabolites known to be detrimental to neuronal damage and their mechanism of action. In addition, we highlight important neurotrophic factors, whose level have been found to be dysregulated in diabetic retina and may damage neurons. Furthermore, we discuss potential drugs and strategies based on targeting diabetes-induced metabolites, metabolic pathways, oxidative stress, and neurotrophins to protect retinal neurons, which may ameliorate vision loss and vascular damage in DR.
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Affiliation(s)
- Mohammad Shamsul Ola
- Department of Biochemistry, College of Science, King Saud University, Riyadh, KSA, Saudi Arabia
| | - Abdullah S Alhomida
- Department of Biochemistry, College of Science, King Saud University, Riyadh, KSA, Saudi Arabia
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23
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Shen W, Chung SH, Irhimeh MR, Li S, Lee SR, Gillies MC. Systemic administration of erythropoietin inhibits retinopathy in RCS rats. PLoS One 2014; 9:e104759. [PMID: 25119659 PMCID: PMC4132022 DOI: 10.1371/journal.pone.0104759] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 07/12/2014] [Indexed: 12/17/2022] Open
Abstract
Objective Royal College of Surgeons (RCS) rats develop vasculopathy as photoreceptors degenerate. The aim of this study was to examine the effect of erythropoietin (EPO) on retinopathy in RCS rats. Methods Fluorescein angiography was used to monitor retinal vascular changes over time. Changes in retinal glia and vasculature were studied by immunostaining. To study the effects of EPO on retinal pathology, EPO (5000 IU/kg) was injected intraperitoneally in 14 week old normal and RCS rats twice a week for 4 weeks. Changes in the retinal vasculature, glia and microglia, photoreceptor apoptosis, differential expression of p75 neurotrophin receptor (p75NTR), pro-neurotrophin 3 (pro-NT3), tumour necrosis factor-α (TNFα), pigment epithelium derived factor (PEDF) and vascular endothelial growth factor-A (VEGF-A), the production of CD34+ cells and mobilization of CD34+/VEGF-R2+ cells as well as recruitment of CD34+ cells into the retina were examined after EPO treatment. Results RCS rats developed progressive capillary dropout and subretinal neovascularization which were accompanied by retinal gliosis. Systemic administration of EPO stabilized the retinal vasculature and inhibited the development of focal vascular lesions. Further studies showed that EPO modulated retinal gliosis, attenuated photoreceptor apoptosis and p75NTR and pro-NT3 upregulation, promoted the infiltration of ramified microglia and stimulated VEGF-A expression but had little effect on TNFα and PEDF expression. EPO stimulated the production of red and white blood cells and CD34+ cells along with effective mobilization of CD34+/VEGF-R2+ cells. Immunofluorescence study demonstrated that EPO enhanced the recruitment of CD34+ cells into the retina. Conclusions Our results suggest that EPO has therapeutic potentials in treatment of neuronal and vascular pathology in retinal disease. The protective effects of EPO on photoreceptors and the retinal vasculature may involve multiple mechanisms including regulation of retinal glia and microglia, inhibition of p75NTR-pro-NT3 signaling together with stimulation of production and mobilization of bone marrow derived cells.
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Affiliation(s)
- Weiyong Shen
- Save Sight Institute, the University of Sydney, Sydney, Australia
| | - Sook H Chung
- Save Sight Institute, the University of Sydney, Sydney, Australia
| | | | - Shiying Li
- Save Sight Institute, the University of Sydney, Sydney, Australia; Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, China
| | - So-Ra Lee
- Save Sight Institute, the University of Sydney, Sydney, Australia
| | - Mark C Gillies
- Save Sight Institute, the University of Sydney, Sydney, Australia
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Wohlfart P, Lin J, Dietrich N, Kannt A, Elvert R, Herling AW, Hammes HP. Expression patterning reveals retinal inflammation as a minor factor in experimental retinopathy of ZDF rats. Acta Diabetol 2014; 51:553-8. [PMID: 24477469 PMCID: PMC4127441 DOI: 10.1007/s00592-013-0550-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 12/19/2013] [Indexed: 12/25/2022]
Abstract
Obese Zucker diabetic fatty (ZDF) rats are used as a type-2 diabetes model for microvascular complications. In order to study retinopathy in this model, changes in retinal vasculature were analyzed by quantitative morphometry and related to retinal expression of 46 selected genes that were analyzed by microfluidic card PCR technology. At 3 months of age, obese animals had developed stable hyperglycemia (20.7 ± 1.3 mmol/L plasma glucose vs. 6.5 ± 0.1 mmol/L in lean). Hyperinsulinemia initially presented in obese rats at 2 months (10.5 ± 0.7 μg/L plasma insulin vs. 0.2 ± 0.04 μg/L in lean) and decreased at 3 months (3.9 ± 0.6 vs. 0.5 ± 0.09 μg/ml in lean). At 8 months of age, animals had developed microvascular complications. An increased number of acellular capillaries in obese (24 ± 5/mm(2)) versus lean (15 ± 4/mm(2)) and a decreased number of retinal pericytes in obese (2,270 ± 250/mm(2)) versus lean animals (1,620 ± 243/mm(2)) could be observed. VEGFa, MIF, and HIF-1α were the most abundantly expressed and inflammatory genes such as TNFα and IL-6 are the least abundantly expressed genes. None of these genes were differentially regulated. Surprisingly, specific growth factors such as bFGF (FGF2) and placental growth factor, and adhesion molecules such as ICAM-1 were abundantly expressed and up-regulated in diabetic versus non-diabetic ZDF rats. In summary, we observed in type-2 diabetic ZDF rats retinopathy with retinal vasoregression along with a simultaneous up-regulation of specific growth factors such as bFGF and adhesion molecules, but only minor changes in key inflammatory genes.
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Affiliation(s)
- Paulus Wohlfart
- R&D Diabetes Division, Research and Translational Medicine, Sanofi, Industriepark Höchst, 65926, Frankfurt, Germany,
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Systemic treatment with erythropoietin protects the neurovascular unit in a rat model of retinal neurodegeneration. PLoS One 2014; 9:e102013. [PMID: 25013951 PMCID: PMC4094460 DOI: 10.1371/journal.pone.0102013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 06/12/2014] [Indexed: 12/14/2022] Open
Abstract
Rats expressing a transgenic polycystic kidney disease (PKD) gene develop photoreceptor degeneration and subsequent vasoregression, as well as activation of retinal microglia and macroglia. To target the whole neuroglialvascular unit, neuro- and vasoprotective Erythropoietin (EPO) was intraperitoneally injected into four –week old male heterozygous PKD rats three times a week at a dose of 256 IU/kg body weight. For comparison EPO-like peptide, lacking unwanted side effects of EPO treatment, was given five times a week at a dose of 10 µg/kg body weight. Matched EPO treated Sprague Dawley and water-injected PKD rats were held as controls. After four weeks of treatment the animals were sacrificed and analysis of the neurovascular morphology, glial cell activity and pAkt localization was performed. The number of endothelial cells and pericytes did not change after treatment with EPO or EPO-like peptide. There was a nonsignificant reduction of migrating pericytes by 23% and 49%, respectively. Formation of acellular capillaries was significantly reduced by 49% (p<0.001) or 40% (p<0.05). EPO-treatment protected against thinning of the central retina by 10% (p<0.05), a composite of an increase of the outer nuclear layer by 12% (p<0.01) and in the outer segments of photoreceptors by 26% (p<0.001). Quantification of cell nuclei revealed no difference. Microglial activity, shown by gene expression of CD74, decreased by 67% (p<0.01) after EPO and 36% (n.s.) after EPO-like peptide treatment. In conclusion, EPO safeguards the neuroglialvascular unit in a model of retinal neurodegeneration and secondary vasoregression. This finding strengthens EPO in its protective capability for the whole neuroglialvascular unit.
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Semeraro F, Cancarini A, Morescalchi F, Romano MR, dell'Omo R, Ruggeri G, Agnifili L, Costagliola C. Serum and intraocular concentrations of erythropoietin and vascular endothelial growth factor in patients with type 2 diabetes and proliferative retinopathy. DIABETES & METABOLISM 2014; 40:445-51. [PMID: 24878492 DOI: 10.1016/j.diabet.2014.04.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 04/16/2014] [Accepted: 04/19/2014] [Indexed: 12/18/2022]
Abstract
AIM This study compared systemic and intraocular concentrations of erythropoietin (EPO) and vascular endothelial growth factor (VEGF) in patients with type 2 diabetes (T2D) and proliferative diabetic retinopathy (PDR) with levels in patients without diabetes, and looked for possible correlations between the concentrations found and other variables analyzed. METHODS Concentrations of EPO and VEGF were measured in the aqueous and vitreous humours and serum of patients undergoing vitrectomy for PDR (33 patients) or for macular holes or puckers (20 control patients). EPO was assayed by radioimmunoassay, with a lower limit of detection (LOD) of 1.0 mIU/mL. VEGF was assayed using enzyme-linked immunosorbent assay (ELISA), with a lower LOD of 10.0 pg/mL. RESULTS EPO concentrations in serum did not differ significantly between the two groups, whereas EPO in vitreous and aqueous were higher in diabetic than in non-diabetic patients. VEGF in serum was lower in diabetic patients than in non-diabetics; conversely, VEGF concentrations in vitreous were significantly higher in diabetic patients. A direct correlation was found between vitreous and aqueous EPO concentrations, and between vitreous EPO and blood glucose concentrations. A significant, negative correlation between vitreous EPO concentration and age was also recorded. CONCLUSION High EPO concentrations in the vitreous of patients with PDR and its correlation with blood glucose suggest that EPO could play a role in the pathogenesis of PDR. All possible factors affecting serum and ocular concentrations of EPO and VEGF should be determined to identify compounds able to prevent and control this serious microvascular complication of diabetes.
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Affiliation(s)
- F Semeraro
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
| | - A Cancarini
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy.
| | - F Morescalchi
- Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, P.le Spedali Civili 1, 25123 Brescia, Italy
| | - M R Romano
- Department of Medicine and Health Sciences, University of Molise, Campobasso, Italy
| | - R dell'Omo
- Department of Medicine and Health Sciences, University of Molise, Campobasso, Italy
| | - G Ruggeri
- Department of Laboratory Medicine, A.O. Spedali Civili, Brescia, Italy
| | - L Agnifili
- Department of Ophthalmology, University of Chieti-Pescara, Chieti, Italy
| | - C Costagliola
- Department of Medicine and Health Sciences, University of Molise, Campobasso, Italy
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McAuley AK, Sanfilippo PG, Hewitt AW, Liang H, Lamoureux E, Wang JJ, Connell PP. Vitreous biomarkers in diabetic retinopathy: a systematic review and meta-analysis. J Diabetes Complications 2014; 28:419-25. [PMID: 24630762 DOI: 10.1016/j.jdiacomp.2013.09.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 09/24/2013] [Accepted: 09/26/2013] [Indexed: 01/09/2023]
Abstract
The aim of this study was to perform a systematic meta-analysis of biomarkers investigated with diabetic retinopathy (DR) in the vitreous, and to explore the molecular pathway interactions of these markers found to be consistently associated with DR. Relevant databases [PubMed and ISI web of science] were searched for all published articles investigating molecular biomarkers of the vitreous associated with DR. Based on set exclusion/inclusion criteria available data from studies with human vitreous samples were extracted and used for our meta-analysis. The interactions of significant biomarkers in DR were investigated via STRING and KEGG pathway analysis. Our meta-analysis of DR identifies eleven biomarkers as potential therapeutic candidates alternate to current anti-VEGF therapy. Four of these are deemed viable therapeutic targets for PDR; ET receptors (ET A and ET B), anti-PDGF-BB, blocking TGF-β using cell therapy and PEDF. The identification of supplementary or synergistic therapeutic candidates to anti VEGF in the treatment of DR may aid in the development of future treatment trials.
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Affiliation(s)
- Annie K McAuley
- Centre for Eye Research Australia, The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia.
| | - Paul G Sanfilippo
- Centre for Eye Research Australia, The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia; Lions Eye Institute, Centre for Ophthalmology and Visual Science, University of Western Australia, Australia
| | - Alex W Hewitt
- Centre for Eye Research Australia, The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia; Lions Eye Institute, Centre for Ophthalmology and Visual Science, University of Western Australia, Australia
| | - Helena Liang
- Centre for Eye Research Australia, The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Ecosse Lamoureux
- Centre for Eye Research Australia, The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia; Office of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore; Singapore Eye Research Institute, Singapore
| | - Jie Jin Wang
- Centre for Eye Research Australia, The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia; Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, Westmead, Australia
| | - Paul P Connell
- Centre for Eye Research Australia, The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia; Mater Misericordiae University Hospital, Dublin, Ireland
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Lu Y, Zhou N, Huang X, Cheng JW, Li FQ, Wei RL, Cai JP. Effect of intravitreal injection of bevacizumab-chitosan nanoparticles on retina of diabetic rats. Int J Ophthalmol 2014; 7:1-7. [PMID: 24634856 DOI: 10.3980/j.issn.2222-3959.2014.01.01] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 09/22/2013] [Indexed: 11/02/2022] Open
Abstract
AIM To investigate the effects of intravitreal injection of bevacizumab-chitosan nanoparticles on pathological morphology of retina and the expression of vascular endothelial growth factor (VEGF) protein and VEGF mRNA in the retina of diabetic rats. METHODS Seventy-two 3-month aged diabetic rats were randomly divided into 3 groups, each containing 24 animals and 48 eyes. Both eyes of the rats in group A were injected into the vitreous at the pars plana with 3µL of physiological saline, while in groups B and C were injected with 3µL (75µg) of bevacizumab and 3µL of bevacizumab-chitosan nanoparticles (containing 75µg of bevacizumab), respectively. Immunohistochemistry was used to assess retinal angiogenesis, real-time PCR assay was used to analyse the expression of VEGF mRNA, and light microscopy was used to evaluate the morphology of retinal capillaries. RESULTS Real-time PCR assay revealed that the VEGF mRNA expression in the retina before injection was similar to 1 week after injection in group A (P>0.05), while the VEGF mRNA expression before injection significantly differed from those 4 and 8 weeks after injection (P<0.05). Retinal expression of VEGF protein and VEGF mRNA was inhibited 1 week and 4 weeks after injection (P<0.05) in group B, and the expression of VEGF protein and VEGF mRNA was obviously inhibited until 8 weeks after injection (P<0.05) in group C. Using multiple comparisons among group A, group B, and group C, the VEGF expression before injection was higher than at 1, 4 and 8 weeks after injection (P<0.05). The amount of VEGF expression was higher 8 weeks after injection than 1 week or 4 weeks after injection, and also higher 1 week after injection compared with 4 weeks after injection (P<0.05). No toxic effect on SD rats was observed with bevacizumab-chitosan nanoparticles injection alone. CONCLUSION The results offer a new approach for inhibiting angiogenesis of diabetic retinopathy and indicate that the intravitreal injection of bevacizumab inhibits VEGF expression in retina, and bevacizumab-chitosan nanoparticles have a longer duration of action.
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Affiliation(s)
- Yan Lu
- Department of Ophthalmology, Changzheng Hospital, the Second Affiliated Hospital of the Second Military Medical University, Shanghai 200003, China ; Department of Ophthalmology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, Jiangsu Province, China
| | - Nan Zhou
- Department of Ophthalmology, Changzheng Hospital, the Second Affiliated Hospital of the Second Military Medical University, Shanghai 200003, China
| | - Xiao Huang
- Department of Ophthalmology, Changzheng Hospital, the Second Affiliated Hospital of the Second Military Medical University, Shanghai 200003, China
| | - Jin-Wei Cheng
- Department of Ophthalmology, Changzheng Hospital, the Second Affiliated Hospital of the Second Military Medical University, Shanghai 200003, China
| | - Feng-Qian Li
- Department of Ophthalmology, Changzheng Hospital, the Second Affiliated Hospital of the Second Military Medical University, Shanghai 200003, China
| | - Rui-Li Wei
- Department of Ophthalmology, Changzheng Hospital, the Second Affiliated Hospital of the Second Military Medical University, Shanghai 200003, China
| | - Ji-Ping Cai
- Department of Ophthalmology, Changzheng Hospital, the Second Affiliated Hospital of the Second Military Medical University, Shanghai 200003, China
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Simó R, Hernández C. Neurodegeneration in the diabetic eye: new insights and therapeutic perspectives. Trends Endocrinol Metab 2014; 25:23-33. [PMID: 24183659 DOI: 10.1016/j.tem.2013.09.005] [Citation(s) in RCA: 324] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 09/02/2013] [Accepted: 09/27/2013] [Indexed: 11/29/2022]
Abstract
Diabetic retinopathy (DR), one of the leading causes of preventable blindness, has been considered a microcirculatory disease of the retina. However, there is emerging evidence to suggest that retinal neurodegeneration is an early event in the pathogenesis of DR, which participates in the development of microvascular abnormalities. Therefore, the study of the underlying mechanisms leading to neurodegeneration and the identification of the mediators in the crosstalk between neurodegeneration and microangiopathy will be essential for the development of new therapeutic strategies. In this review, an updated discussion of the mechanisms involved in neurodegeneration, as well as the link between neurodegeneration and microangiopathy, is presented. Finally, the therapeutic implications and new perspectives based on identifying those patients with retinal neurodegeneration are given.
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Affiliation(s)
- Rafael Simó
- CIBERDEM (CIBER de Diabetes y Enfermedades Metabólicas Asociadas) and Diabetes and Metabolism Research Unit, Vall Hebron Institut de Recerca (VHIR), Universitat Autónoma de Barcelona, 08035 Barcelona, Spain.
| | - Cristina Hernández
- CIBERDEM (CIBER de Diabetes y Enfermedades Metabólicas Asociadas) and Diabetes and Metabolism Research Unit, Vall Hebron Institut de Recerca (VHIR), Universitat Autónoma de Barcelona, 08035 Barcelona, Spain
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Szabadfi K, Pinter E, Reglodi D, Gabriel R. Neuropeptides, trophic factors, and other substances providing morphofunctional and metabolic protection in experimental models of diabetic retinopathy. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 311:1-121. [PMID: 24952915 DOI: 10.1016/b978-0-12-800179-0.00001-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Vision is the most important sensory modality for many species, including humans. Damage to the retina results in vision loss or even blindness. One of the most serious complications of diabetes, a disease that has seen a worldwide increase in prevalence, is diabetic retinopathy. This condition stems from consequences of pathological metabolism and develops in 75% of patients with type 1 and 50% with type 2 diabetes. The development of novel protective drugs is essential. In this review we provide a description of the disease and conclude that type 1 diabetes and type 2 diabetes lead to the same retinopathy. We evaluate existing experimental models and recent developments in finding effective compounds against this disorder. In our opinion, the best models are the long-term streptozotocin-induced diabetes and Otsuka Long-Evans Tokushima Fatty and spontaneously diabetic Torii rats, while the most promising substances are topically administered somatostatin and pigment epithelium-derived factor analogs, antivasculogenic substances, and systemic antioxidants. Future drug development should focus on these.
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Affiliation(s)
- Krisztina Szabadfi
- Department of Experimental Zoology and Neurobiology, University of Pecs, Pecs, Hungary; Janos Szentagothai Research Center, University of Pecs, Pecs, Hungary.
| | - Erika Pinter
- Janos Szentagothai Research Center, University of Pecs, Pecs, Hungary; Department of Pharmacology and Pharmacotherapy, University of Pecs, Pecs, Hungary
| | - Dora Reglodi
- Department of Anatomy, PTE MTA Lendulet-PACAP Research Team, University of Pecs, Pecs, Hungary
| | - Robert Gabriel
- Department of Experimental Zoology and Neurobiology, University of Pecs, Pecs, Hungary; Janos Szentagothai Research Center, University of Pecs, Pecs, Hungary
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Dietrich N, Hammes HP. Retinal digest preparation: a method to study diabetic retinopathy. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2013; 933:291-302. [PMID: 22893415 DOI: 10.1007/978-1-62703-068-7_19] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Retinal digestion is a commonly used method for studying experimental diabetic retinopathy in animal models. The method allows to assess qualitatively and quantitatively the morphology of the retinal vasculature, including characteristics of endothelial cells and pericytes. The digestion method uses the enzyme trypsin and enables the precise evaluation of venolar and arteriolar diameters, endothelial cell and pericyte numbers, and the formation of acellular capillaries.
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Affiliation(s)
- Nadine Dietrich
- 5th Medical Department, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
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32
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Lai AKW, Lo ACY. Animal models of diabetic retinopathy: summary and comparison. J Diabetes Res 2013; 2013:106594. [PMID: 24286086 PMCID: PMC3826427 DOI: 10.1155/2013/106594] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 09/02/2013] [Accepted: 09/02/2013] [Indexed: 12/16/2022] Open
Abstract
Diabetic retinopathy (DR) is a microvascular complication associated with chronic exposure to hyperglycemia and is a major cause of blindness worldwide. Although clinical assessment and retinal autopsy of diabetic patients provide information on the features and progression of DR, its underlying pathophysiological mechanism cannot be deduced. In order to have a better understanding of the development of DR at the molecular and cellular levels, a variety of animal models have been developed. They include pharmacological induction of hyperglycemia and spontaneous diabetic rodents as well as models of angiogenesis without diabetes (to compensate for the absence of proliferative DR symptoms). In this review, we summarize the existing protocols to induce diabetes using STZ. We also describe and compare the pathological presentations, in both morphological and functional aspects, of the currently available DR animal models. The advantages and disadvantages of using different animals, ranging from zebrafish, rodents to other higher-order mammals, are also discussed. Until now, there is no single model that displays all the clinical features of DR as seen in human. Yet, with the understanding of the pathological findings in these animal models, researchers can select the most suitable models for mechanistic studies or drug screening.
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Affiliation(s)
- Angela Ka Wai Lai
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Amy C. Y. Lo
- Department of Ophthalmology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Research Center of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- *Amy C. Y. Lo:
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Hypoxia-induced oxidative stress in ischemic retinopathy. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:426769. [PMID: 23125893 PMCID: PMC3483772 DOI: 10.1155/2012/426769] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 08/24/2012] [Accepted: 09/17/2012] [Indexed: 12/28/2022]
Abstract
Oxidative stress plays a crucial role in the pathogenesis of retinal ischemia/hypoxia, a complication of ocular diseases such as diabetic retinopathy (DR) and retinopathy of prematurity (ROP). Oxidative stress refers to the imbalance between the production of reactive oxygen species (ROS) and the ability to scavenge these ROS by endogenous antioxidative systems. Free radicals and ROS are implicated in the irreversible damage to cell membrane, DNA, and other cellular structures by oxidizing lipids, proteins, and nucleic acids. Anti-oxidants that can inhibit the oxidative processes can protect retinal cells from ischemic/hypoxic insults. In particular, treatment using anti-oxidants such as vitamin E and lutein, inhibition of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) or related signaling pathways, and administration of catalase and superoxide dismutase (SOD) are possible therapeutic regimens for DR, ROP, and other retinal ischemic diseases. The role of oxidative stress in the pathogenesis of DR and ROP as well as the underlying mechanisms involved in the hypoxia/ischemia-induced oxidative damage is discussed. The information provided will be beneficial in understanding the underlying mechanisms involved in the pathogenesis of the diseases as well as in developing effective therapeutic interventions to treat oxidative stress-induced damages.
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Abstract
Diabetic retinopathy (DR) has been considered to be a microcirculatory disease of the retina. However, there is emerging evidence to suggest that retinal neurodegeneration is an early event in the pathogenesis of DR, which may antedate, and also participates in, the microcirculatory abnormalities that occur in DR. Therefore, the study of the underlying mechanisms that lead to neurodegeneration will be essential for identifying new therapeutic targets in the early stages of DR. Elevated levels of glutamate, oxidative stress, the overexpression of the renin-angiotensin system and the upregulation of RAGE play an essential role in the retinal neurodegeneration induced by diabetes. Finally, the balance between the neurotoxic and neuroprotective factors is crucial in determining the survival of retinal neurons. In this review we will focus on neurotrophic factors already synthesized by the retina in physiological conditions as a new therapy strategy for neuroprotection.
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Affiliation(s)
- Cristina Hernández
- CIBERDEM and Diabetes and Metabolism Research Unit, Vall Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Spain
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35
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Abstract
Proliferative diabetic retinopathy (PDR), characterized by pathologic retinal angiogenesis, is a major cause of blindness in the USA and globally. Treatments targeting vascular endothelial growth factor (VEGF) have emerged as a beneficial part of the therapeutic armamentarium for this condition, highlighting the utility of identifying and targeting specific pathogenic molecules. There continues to be active research into the molecular players regulating retinal angiogenesis, including pro-angiogenic factors, anti-angiogenic factors, and integrins and matrix proteinases. New insights have been especially prominent regarding molecules which regulate specialized endothelial cells called tip cells, which play a lead role in endothelial sprouting. Together, these research efforts are uncovering new, important molecular regulators of retinal angiogenesis, which provide fertile areas for therapeutic exploration. This review discusses potential molecular targets, with an emphasis towards newer targets.
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Affiliation(s)
- Shuang Wang
- Ophthalmologic Department, China-Japan Union Hospital, Changchun City, Jilin Province, China.
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Hernández C, Simó R. Erythropoietin produced by the retina: its role in physiology and diabetic retinopathy. Endocrine 2012; 41:220-6. [PMID: 22167324 DOI: 10.1007/s12020-011-9579-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Accepted: 12/01/2011] [Indexed: 12/22/2022]
Abstract
Erythropoietin (Epo) is the principal regulator of erythropoiesis by inhibiting apoptosis and by stimulating the proliferation and differentiation of erythroid precursor cells. However, Epo also performs extra-erythropoietic actions of which the neuroprotective effects are among the most relevant. Apart from kidney and liver, Epo is also produced by the brain and the retina. In addition, Epo receptor (Epo-R) expression has also been found in the brain and in the retina, thus suggesting an autocrine/paracrine action which seems essential for the physiological homeostasis of both brain and retina. In this review, we will give an overview of the current concepts of the physiology of Epo and will focus on its role in the retina in both normal conditions and in the setting of diabetic retinopathy. Finally, the reasons as to why Epo could be contemplated as a potential new treatment for the early stages of diabetic retinopathy will be given.
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Affiliation(s)
- Cristina Hernández
- CIBERDEM, Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain
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37
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Caprara C, Grimm C. From oxygen to erythropoietin: relevance of hypoxia for retinal development, health and disease. Prog Retin Eye Res 2011; 31:89-119. [PMID: 22108059 DOI: 10.1016/j.preteyeres.2011.11.003] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 11/01/2011] [Accepted: 11/07/2011] [Indexed: 12/20/2022]
Abstract
Photoreceptors and other cells of the retina consume large quantities of energy to efficiently convert light information into a neuronal signal understandable by the brain. The necessary energy is mainly provided by the oxygen-dependent generation of ATP in the numerous mitochondria of retinal cells. To secure the availability of sufficient oxygen for this process, the retina requires constant blood flow through the vasculature of the retina and the choroid. Inefficient supply of oxygen and nutrients, as it may occur in conditions of disturbed hemodynamics or vascular defects, results in tissue ischemia or hypoxia. This has profound consequences on retinal function and cell survival, requiring an adaptational response by cells to cope with the reduced oxygen tension. Central to this response are hypoxia inducible factors, transcription factors that accumulate under hypoxic conditions and drive the expression of a large variety of target genes involved in angiogenesis, cell survival and metabolism. Prominent among these factors are vascular endothelial growth factor and erythropoietin, which may contribute to normal angiogenesis during development, but may also cause neovascularization and vascular leakage under pathologically reduced oxygen levels. Since ischemia and hypoxia may have a role in various retinal diseases such as diabetic retinopathy and retinopathy of prematurity, studying the cellular and molecular response to reduced tissue oxygenation is of high relevance. In addition, the concept of preconditioning with ischemia or hypoxia demonstrates the capacity of the retina to activate endogenous survival mechanisms, which may protect cells against a following noxious insult. Part of these mechanisms is the local production of protective factors such as erythropoietin. Due to its plethora of effects in the retina including neuro- and vaso-protective activities, erythropoietin has gained strong interest as potential therapeutic factor for retinal degenerative diseases.
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Affiliation(s)
- Christian Caprara
- Lab for Retinal Cell Biology, Department of Ophthalmology, University of Zurich, Zurich, Switzerland
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