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Seyyar SA, Tokuç EÖ, Soysal GG. Effect of diabetic macular oedema on serum iron status indicators. Clin Exp Optom 2024; 107:313-317. [PMID: 37309021 DOI: 10.1080/08164622.2023.2218997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 05/24/2023] [Indexed: 06/14/2023] Open
Abstract
CLINICAL RELEVANCE The role of subclinical inflammation in the pathophysiology of diabetic macular oedema (DME), which is known to be quite complex, is of much interest. Serum ferritin level, which is an indicator of body iron stores, is both an inflammatory marker for various neurodegenerative diseases and an important indicator in the evaluation of iron-induced oxidative stress. BACKGROUND Iron metabolism indicators play a role in the formation and development of diabetic retinopathy, which is known to be associated with subclinical inflammation, and may also play a role in the pathogenesis of DME. The aim of this study was to investigate the role of serum iron metabolism markers in the pathogenesis of DME. MATERIALS AND METHODS The files of all nonproliferative diabetic retinopathy (NPDR) patients who were scheduled for the first intravitreal injection for DME in the eye clinic between January 2019 and January 2020 were reviewed retrospectively. By examining the files of all diabetes mellitus patients who attended the outpatient eye clinic on the same dates, those without retinopathy and those with NPDR but not DME were recorded. All results, including a comprehensive ophthalmological examination, laboratory data of fasting blood tests, and an internal medicine outpatient examination were collected for analysis. RESULTS Of the 157 participants, 44 were NPDR patients with oedema, 50 were NPDR patients without oedema, and 63 were patients without retinopathy. There was a significant difference between the groups in respect of creatinine, high-density lipoprotein, mean corpuscular volume, serum iron and ferritin, total iron binding capacity and transferrin saturation (p < 0.050). Ferritin values were found to be significantly higher in patients with macular oedema. Other iron status markers were found to be significantly lower (p < 0.050). CONCLUSION Evaluation of serum iron status indicators in the routine follow-up of diabetic patients may be of diagnostic and/or prognostic benefit in terms of DME.
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Affiliation(s)
- Sevim Ayça Seyyar
- Ophthalmology Department, Gaziantep University Hospital, Gaziantep, Turkey
| | - Ecem Önder Tokuç
- Ophthalmology Department, Kocaeli University Hospital, Kocaeli, Turkey
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Bogdanov P, Duarri A, Sabater D, Salas A, Isla-Magrané H, Ramos H, Huerta J, Valeri M, García-Arumí J, Simó R, Hernández C. Blocking Hemopexin With Specific Antibodies: A New Strategy for Treating Diabetic Retinopathy. Diabetes 2023; 72:1841-1852. [PMID: 37722135 DOI: 10.2337/db23-0027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 09/05/2023] [Indexed: 09/20/2023]
Abstract
Hemopexin (HPX) is overexpressed in the retina of patients with diabetes and induces the breakdown of the blood-retinal barrier in vitro. The aim of this study was to evaluate whether HPX blockade by specific antibodies (aHPX) could avoid vascular leakage in vivo and microvascular angiogenesis in vitro and ex vivo. For this purpose, the effect of intravitreal (IVT) injections of aHPX on vascular leakage was evaluated in db/db mice and rats with streptozotocin-induced diabetes using the Evans Blue method. Retinal neurodegeneration and inflammation were also evaluated. The antiangiogenic effect of aHPX on human retinal endothelial cells (HRECs) was tested by scratch wound healing and tube formation using standardized methods, as well as by choroidal sprouting assays from retinal explants obtained in rats. We found that IVT injection of aHPX significantly reduced vascular leakage, retinal neurodegeneration, and inflammation. In addition, treatment with aHPX significantly reduced HREC migration and tube formation induced by high glucose concentration and suppressed choroidal sprouting even after vascular endothelial growth factor stimulation, with this effect being higher than obtained with bevacizumab. The antipermeability and antiangiogenic effects of IVT injection of aHPX suggest the blockade or inhibition of HPX as a new strategy for the treatment of advanced stages of diabetic retinopathy. ARTICLE HIGHLIGHTS Hemopexin (HPX) is the best-characterized permeability factor in steroid-sensitive nephrotic syndrome. We have previously reported that HPX is overexpressed in the retina of patients with diabetes and induces the breakdown of the blood-retinal barrier in vitro. Here, we report that intravitreal injection of anti-HPX antibodies significantly reduces vascular leakage, retinal neurodegeneration, and inflammation in diabetic murine models and that the immunoneutralization of HPX exerts a significant antiangiogenic effect in vitro and in retinal explants. The blockade of HPX can be considered as a new therapy for advanced stages of diabetic retinopathy.
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Affiliation(s)
- Patricia Bogdanov
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Madrid, Spain
| | - Anna Duarri
- Ophthalmology Research Group, Vall d'Hebron Institut de Recerca, Barcelona, Spain
| | - David Sabater
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Anna Salas
- Ophthalmology Research Group, Vall d'Hebron Institut de Recerca, Barcelona, Spain
| | - Helena Isla-Magrané
- Ophthalmology Research Group, Vall d'Hebron Institut de Recerca, Barcelona, Spain
| | - Hugo Ramos
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Madrid, Spain
| | - Jordi Huerta
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Valeri
- Unit of High Technology, Vall d'Hebron Research Institute, Barcelona, Spain
| | - José García-Arumí
- Ophthalmology Research Group, Vall d'Hebron Institut de Recerca, Barcelona, Spain
| | - Rafael Simó
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Madrid, Spain
| | - Cristina Hernández
- Diabetes and Metabolism Research Unit, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Madrid, Spain
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Li Y, Cheng ZX, Luo T, Lyu HB. Therapeutic potential of iron chelators in retinal vascular diseases. Int J Ophthalmol 2023; 16:1899-1910. [PMID: 38028518 PMCID: PMC10626364 DOI: 10.18240/ijo.2023.11.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 08/24/2023] [Indexed: 12/01/2023] Open
Abstract
Iron is one of the necessary metal elements in the human body. There are numerous factors that control the balance of iron metabolism, and its storage and transportation mechanisms are intricate. As one of the most energy-intensive tissues in the body, the retina is susceptible to iron imbalance. The occurrence of iron overload in the retina leads to the generation of a significant quantity of reactive oxygen species. This will aggravate local oxidative stress and inflammatory reactions and even lead to ferroptosis, eventually resulting in retinal dysfunction. The blood-retina-retinal barrier is eventually harmed by oxidative stress and elevated inflammation, which are characteristics of retinal vascular disorders. The pathophysiology of retinal vascular disorders may be significantly influenced by iron. Recently, iron-chelating agents have been found to have antioxidative and anti-inflammatory actions in addition to iron chelating. Therefore, iron neutralization is considered to be a new and potentially useful therapeutic strategy. This article reviews the iron overload in retinal vascular diseases and discusses the therapeutic potential of iron-chelating agents.
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Affiliation(s)
- Yan Li
- Department of Ophthalmology, the Affiliated Hospital of Southwest Medical University, Luzhou 646000, Sichuan Province, China
- Department of Ophthalmology, the People's Hospital of Jianyang, Chengdu 641400, Sichuan Province, China
| | - Zi-Xuan Cheng
- Department of Ophthalmology, the Affiliated Hospital of Southwest Medical University, Luzhou 646000, Sichuan Province, China
| | - Ting Luo
- Department of Ophthalmology, the Affiliated Hospital of Southwest Medical University, Luzhou 646000, Sichuan Province, China
- Department of Ophthalmology, the People's Hospital of Jianyang, Chengdu 641400, Sichuan Province, China
| | - Hong-Bin Lyu
- Department of Ophthalmology, the Affiliated Hospital of Southwest Medical University, Luzhou 646000, Sichuan Province, China
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Ouyang J, Zhou L, Wang Q. Spotlight on iron and ferroptosis: research progress in diabetic retinopathy. Front Endocrinol (Lausanne) 2023; 14:1234824. [PMID: 37772084 PMCID: PMC10525335 DOI: 10.3389/fendo.2023.1234824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/21/2023] [Indexed: 09/30/2023] Open
Abstract
Iron, as the most abundant metallic element within the human organism, is an indispensable ion for sustaining life and assumes a pivotal role in governing glucose and lipid metabolism, along with orchestrating inflammatory responses. The presence of diabetes mellitus (DM) can induce aberrant iron accumulation within the corporeal system. Consequentially, iron overload precipitates a sequence of important adversities, subsequently setting in motion a domino effect wherein ferroptosis emerges as the utmost pernicious outcome. Ferroptosis, an emerging variant of non-apoptotic regulated cell death, operates independently of caspases and GSDMD. It distinguishes itself from alternative forms of controlled cell death through distinctive morphological and biochemical attributes. Its principal hallmark resides in the pathological accrual of intracellular iron and the concomitant generation of iron-driven lipid peroxides. Diabetic retinopathy (DR), established as the predominant cause of adult blindness, wields profound influence over the well-being and psychosocial strain experienced by afflicted individuals. Presently, an abundance of research endeavors has ascertained the pervasive engagement of iron and ferroptosis in the microangiopathy inherent to DR. Evidently, judicious management of iron overload and ferroptosis in the early stages of DR bears the potential to considerably decelerate disease progression. Within this discourse, we undertake a comprehensive exploration of the regulatory mechanisms governing iron homeostasis and ferroptosis. Furthermore, we expound upon the subsequent detriments induced by their dysregulation. Concurrently, we elucidate the intricate interplay linking iron overload, ferroptosis, and DR. Delving deeper, we engage in a comprehensive deliberation regarding strategies to modulate their influence, thereby effecting prospective interventions in the trajectory of DR's advancement or employing them as therapeutic modalities.
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Affiliation(s)
- Junlin Ouyang
- Department of Endocrinology, China–Japan Union Hospital of Jilin University, Changchun, Jilin, China
| | - Ling Zhou
- Department of Obstetrics and Gynecology, China–Japan Union Hospital of Jilin University, Changchun, Jilin, China
| | - Qing Wang
- Department of Endocrinology, China–Japan Union Hospital of Jilin University, Changchun, Jilin, China
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Li C, Xiao C, Tao H, Tang X. Research progress of iron metabolism in retinal diseases. ADVANCES IN OPHTHALMOLOGY PRACTICE AND RESEARCH 2023; 3:93-100. [PMID: 37846377 PMCID: PMC10577842 DOI: 10.1016/j.aopr.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 02/20/2023] [Accepted: 02/22/2023] [Indexed: 10/18/2023]
Abstract
Background Retinal diseases can lead to severe visual impairment and even blindness, but current treatments are limited. For precise targeted therapy, the pathophysiological mechanisms of the diseases still need to be further explored. Iron serves an essential role in many biological activities and helps maintain the function and morphology of the retina. The vision problems caused by retinal diseases are affecting more and more people, the study of iron metabolism in retinal diseases possesses great potential for clinical application. Main text Iron maintains a dynamic balance in the retina but in excess is toxic to the retina. Iron overload can lead to various pathological changes in the retina through oxidative stress, inflammation, cell death, angiogenesis and other pathways. It is therefore involved in the progression of retinal diseases such as age-related macular degeneration, glaucoma, diabetic retinopathy, retinitis pigmentosa, and hereditary iron overload. In recent years, iron chelators have been shown to be effective in the treatment of retinal diseases, but the exact mechanism is not yet fully understood. This question prompted further investigation into the specific mechanisms by which iron metabolism is involved in retinal disease. Conclusions This review summarizes iron metabolism processes in the retina and mechanistic studies of iron metabolism in the progression of retinal disease. It also highlights the therapeutic potential of iron chelators in retinal diseases.
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Affiliation(s)
- Cunzi Li
- Department of Ophthalmology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Chunyu Xiao
- Department of Ophthalmology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Hui Tao
- Department of Ophthalmology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Xianling Tang
- Department of Ophthalmology, Shenzhen Third People's Hospital, Shenzhen, China
- The First Affiliated Hospital of Harbin Medical University, Harbin, China
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Bonet A, Pampalona J, Jose-Cunilleras E, Nacher V, Ruberte J. Ferritin But Not Iron Increases in Retina Upon Systemic Iron Overload in Diabetic and Iron-Dextran Injected Mice. Invest Ophthalmol Vis Sci 2023; 64:22. [PMID: 36912597 PMCID: PMC10019492 DOI: 10.1167/iovs.64.3.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023] Open
Abstract
Purpose Iron overload causes oxidative damage in the retina, and it has been involved in the pathogeny of diabetic retinopathy, which is one of the leading causes of blindness in the adult population worldwide. However, how systemic iron enters the retina during diabetes and the role of blood retinal barrier (BRB) in this process remains unclear. Methods The db/db mouse, a well-known model of type 2 diabetes, and a model of systemic iron overload induced by iron dextran intraperitoneal injection, were used. Perls staining and mass spectrophotometry were used to study iron content. Western blot and immunohistochemistry of iron handling proteins were performed to study systemic and retinal iron metabolism. BRB function was assessed by analyzing vascular leakage in fundus angiographies, whole retinas, and retinal sections and by studying the status of tight junctions using transmission electron microscopy and Western blot analysis. Results Twenty-week-old db/db mice with systemic iron overload presented ferritin overexpression without iron increase in the retina and did not show any sign of BRB breakdown. These findings were also observed in iron dextran-injected mice. In those animals, after BRB breakdown induced by cryopexy, iron entered massively in the retina. Conclusions Our results suggested that BRB protects the retina from excessive iron entry in early stages of diabetic retinopathy. Furthermore, ferritin overexpression before iron increase may prepare the retina for a potential BRB breakdown and iron entry from the systemic circulation.
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Affiliation(s)
- Aina Bonet
- Centre for Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona, Bellaterra, Spain.,Department of Animal Health and Anatomy, Faculty of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Judit Pampalona
- Centre for Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Eduard Jose-Cunilleras
- Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Víctor Nacher
- Department of Animal Health and Anatomy, Faculty of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Jesús Ruberte
- Centre for Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona, Bellaterra, Spain.,Department of Animal Health and Anatomy, Faculty of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
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5-Lipoxygenase Inhibition Protects Retinal Pigment Epithelium from Sodium Iodate-Induced Ferroptosis and Prevents Retinal Degeneration. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:1792894. [PMID: 35251467 PMCID: PMC8890867 DOI: 10.1155/2022/1792894] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/29/2022] [Indexed: 01/15/2023]
Abstract
Excessive reactive oxygen species (ROS) contribute to damage of retinal cells and the development of retinal diseases including age-related macular degeneration (AMD). ROS result in increased metabolites of lipoxygenases (LOXs), which react with ROS to induce lipid peroxidation and may lead to ferroptosis. In this study, the effect of 5-LOX inhibition on alleviating ROS-induced cell death was evaluated using sodium iodate (NaIO3) in the retinal pigment epithelium (RPE) cell line ARPE-19 and a mouse model investigating oxidative stress in AMD. We demonstrated that NaIO3 induced cell death in the RPE cells through mechanisms including ferroptosis. Inhibition of 5-LOX with specific inhibitor, Zileuton, or siRNA knockdown of ALXO5 mitigated NaIO3-induced lipid peroxidation, mitochondrial damage, DNA impairment, and cell death in ARPE-19 cells. Additionally, in the mouse model, pretreatment with Zileuton reduced the NaIO3-induced lipid peroxidation of RPE cells, cell death in the photoreceptor layer of the retina, inflammatory responses, and degeneration of both the neuroretina and RPE monolayer cells. Our results suggest that 5-LOX plays a crucial role in ROS-induced cell death in the RPE and that regulating 5-LOX activity could be a useful approach to control ROS and ferroptosis-induced damage, which promote degeneration in retinal diseases.
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Kaur N, Singh IR, Vanita V. Association of Erythropoietin Gene Polymorphisms With Type 2 Diabetic Retinopathy in Adult Patients From Northern India. Can J Diabetes 2021; 45:785-791. [PMID: 34045145 DOI: 10.1016/j.jcjd.2021.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 08/03/2020] [Accepted: 03/26/2021] [Indexed: 12/21/2022]
Abstract
OBJECTIVES Our aim in this study was to determine the association of erythropoietin (EPO) gene polymorphisms with diabetic retinopathy in type 2 diabetes patients from northern India. METHODS In this case-control study, we recruited 614 participants, consisting of 302 diabetic retinopathy cases and 312 individuals with confirmed type 2 diabetes without retinopathy as controls. EPO polymorphism analysis was performed in all participants using polymerase chain reaction and direct DNA sequence analysis. RESULTS The genotype distribution and allele frequency of the c.246+265G>A (rs507392) polymorphism in differed significantly (p<0.05) between the retinopathy and control groups. For the -1306C>A (rs1617640) polymorphism, genotype distribution among the 2 groups analyzed differed significantly (p=0.047), but the distribution of allele frequency was not found to be statistically significant (p=0.07). For the c.∗772G>T (rs551238) variant, genotype distribution did not differ significantly when comparing the 2 groups (p=0.062), but allele frequency distribution did differ significantly (p=0.045). For the polymorphisms analyzed, namely rs507392 and rs1617640, a statistically significant association with retinopathy was observed (dominant model: adjusted odds ratio [OR], 2.23; 95% confidence interval [CI], 1.36 to 3.35; p<0.01; codominant model: adjusted OR, 1.45; 95% CI, 1.00 to 2.09; p=0.048). However, no significant association between c.∗772G>T (rs551238) polymorphism and diabetic retinopathy was found. CONCLUSIONS Our findings show 2 polymorphisms (c.246+265G>A [rs507392] and -1306C>A [rs1617640]) in EPO to be risk factors for type 2 diabetic retinopathy in a northern Indian cohort. To our knowledge, this is the first report from India to demonstrate an association between EPO gene polymorphisms and retinopathy.
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Affiliation(s)
- Navdeep Kaur
- Department of Human Genetics, Guru Nanak Dev University, Amritsar, Punjab, India
| | - Indu R Singh
- Dr. Daljit Singh Eye Hospital, Amritsar, Punjab, India
| | - Vanita Vanita
- Department of Human Genetics, Guru Nanak Dev University, Amritsar, Punjab, India.
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Bhusal A, Lee WH, Suk K. Lipocalin-2 in Diabetic Complications of the Nervous System: Physiology, Pathology, and Beyond. Front Physiol 2021; 12:638112. [PMID: 33613327 PMCID: PMC7892766 DOI: 10.3389/fphys.2021.638112] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 01/19/2021] [Indexed: 01/04/2023] Open
Abstract
Lipocalin-2 (LCN2) is a 25 kDa secreted protein that belongs to the family of lipocalins, a group of transporters of small hydrophobic molecules such as iron, fatty acids, steroids, and lipopolysaccharide in circulation. LCN2 was previously found to be involved in iron delivery, pointing toward a potential role for LCN2 in immunity. This idea was further validated when LCN2 was found to limit bacterial growth during infections in mice by sequestering iron-laden siderophores. Recently, LCN2 was also identified as a critical regulator of energy metabolism, glucose and lipid homeostasis, and insulin function. Furthermore, studies using Lcn2 knockout mice suggest an important role for LCN2 in several biobehavioral responses, including cognition, emotion, anxiety, and feeding behavior. Owing to its expression and influence on multiple metabolic and neurological functions, there has emerged a great deal of interest in the study of relationships between LCN2 and neurometabolic complications. Thorough investigation has demonstrated that LCN2 is involved in several neurodegenerative diseases, while more recent studies have shown that LCN2 is also instrumental for the progression of diabetic complications like encephalopathy and peripheral neuropathy. Preliminary findings have shown that LCN2 is also a promising drug target and diagnostic marker for the treatment of neuropathic complications from diabetes. In particular, future translational research related to LCN2, such as the development of small-molecule inhibitors or neutralizing antibodies against LCN2, appears essential for exploring its potential as a therapeutic target.
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Affiliation(s)
- Anup Bhusal
- Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, South Korea.,BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Won-Ha Lee
- School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, South Korea
| | - Kyoungho Suk
- Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, South Korea.,BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, School of Medicine, Kyungpook National University, Daegu, South Korea.,Brain Science and Engineering Institute, Kyungpook National University, Daegu, South Korea
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Micera A, Bruno L, Cacciamani A, Rongioletti M, Squitti R. Alzheimer's Disease and Retinal Degeneration: A Glimpse at Essential Trace Metals in Ocular Fluids and Tissues. Curr Alzheimer Res 2020; 16:1073-1083. [PMID: 31642780 DOI: 10.2174/1567205016666191023114015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 09/28/2019] [Accepted: 10/21/2019] [Indexed: 01/19/2023]
Abstract
BACKGROUND Life expectancy is increasing all over the world, although neurodegenerative disorders might drastically affect the individual activity of aged people. Of those, Alzheimer's Disease (AD) is one of the most social-cost age-linked diseases of industrialized countries. To date, retinal diseases seem to be more common in the developing world and characterize principally aged people. Agerelated Macular Degeneration (AMD) is a late-onset, neurodegenerative retinal disease that shares several clinical and pathological features with AD, including stress stimuli such as oxidative stress, inflammation and amyloid formations. METHODS In both diseases, the detrimental intra/extra-cellular deposits have many similarities. Aging, hypercholesterolemia, hypertension, obesity, arteriosclerosis and smoking are risk factors to develop both diseases. Cellular aging routes have similar organelle and signaling patterns in retina and brain. The possibility to find out new research strategies represent a step forward to disclose potential treatment for both of them. Essential trace metals play critical roles in both physiological and pathological condition of retina, optic nerve and brain, by influencing metabolic processes chiefly upon complex multifactorial pathogenesis. CONCLUSION Hence, this review addresses current knowledge about some up-to-date investigated essential trace metals associated with AD and AMD. Changes in the levels of systemic and ocular fluid essential metals might reflect the early stages of AMD, possibly disclosing neurodegeneration pathways shared with AD, which might open to potential early detection.
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Affiliation(s)
- Alessandra Micera
- Research Laboratories in Ophthalmology, IRCCS - Fondazione Bietti, Rome, Italy
| | - Luca Bruno
- Research Laboratories in Ophthalmology, IRCCS - Fondazione Bietti, Rome, Italy
| | - Andrea Cacciamani
- Research Laboratories in Ophthalmology, IRCCS - Fondazione Bietti, Rome, Italy
| | - Mauro Rongioletti
- Department of Laboratory Medicine, Research and Development Division, San Giovanni Calibita, Fatebenefratelli Hospital, Isola Tiberina, Rome, Italy
| | - Rosanna Squitti
- IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, BS, Italy
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Van Hove I, De Groef L, Boeckx B, Modave E, Hu TT, Beets K, Etienne I, Van Bergen T, Lambrechts D, Moons L, Feyen JHM, Porcu M. Single-cell transcriptome analysis of the Akimba mouse retina reveals cell-type-specific insights into the pathobiology of diabetic retinopathy. Diabetologia 2020; 63:2235-2248. [PMID: 32734440 DOI: 10.1007/s00125-020-05218-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 05/08/2020] [Indexed: 12/12/2022]
Abstract
AIMS/HYPOTHESIS Diabetic retinopathy is a common complication of diabetes and a leading cause of visual impairment and blindness. Despite recent advances, our understanding of its pathophysiology remains incomplete. The aim of this study was to provide deeper insight into the complex network of molecular and cellular changes that underlie diabetic retinopathy by systematically mapping the transcriptional changes that occur in the different cellular compartments of the degenerating diabetic mouse retina. METHODS Single-cell RNA sequencing was performed on retinal tissue from 12-week-old wild-type and Akimba (Ins2Akita×Vegfa+/-) mice, which are known to replicate features of clinical diabetic retinopathy. This resulted in transcriptome data for 9474 retinal cells, which could be annotated to eight distinct retinal cell types. Using STRING analysis, we studied differentially expressed gene networks in neuronal, glial and immune cell compartments to create a comprehensive view on the pathological changes that occur in the Akimba retina. Using subclustering analysis, we further characterised macroglial and inflammatory cell subpopulations. Prominent findings were confirmed at the protein level using immunohistochemistry, western blotting and ELISA. RESULTS At 12 weeks, the Akimba retina was found to display degeneration of rod photoreceptors and presence of inflammatory cells, identified by subclustering analysis as monocyte, macrophage and microglial populations. Analysis of differentially expressed genes in the rod, cone, bipolar cell and macroglial compartments indicated changes in cell metabolism and ribosomal gene expression, gliosis, activation of immune system pathways and redox and metal ion dyshomeostasis. Experiments at the protein level supported a metabolic shift from glycolysis to oxidative phosphorylation (glyceraldehyde 3-phosphate dehydrogenase), activation of microglia/macrophages (isolectin-B4), metal ion and oxidative stress response (metallothionein and haem oxygenase-1) and reactive macroglia (glial fibrillary acidic protein and S100) in the Akimba retina, compared with wild-type mice. Our single-cell approach also indicates macroglial subpopulations with distinct fibrotic, inflammatory and gliotic profiles. CONCLUSIONS/INTERPRETATION Our study identifies molecular pathways underlying inflammatory, metabolic and oxidative stress-mediated changes in the Akimba mouse model of diabetic retinopathy and distinguishes distinct functional subtypes of inflammatory and macroglial cells. DATA AVAILABILITY RNA-seq data have been deposited in the ArrayExpress database at EMBL-EBI ( www.ebi.ac.uk/arrayexpress ) under accession number E-MTAB-9061. Graphical abstract.
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Affiliation(s)
- Inge Van Hove
- Oxurion NV, Gaston Geenslaan 1, B-3001, Leuven, Belgium
| | - Lies De Groef
- Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven, Naamsestraat 61, B-3000, Leuven, Belgium
| | - Bram Boeckx
- VIB Center for Cancer Biology, B-3000, Leuven, Belgium
- Laboratory of Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Elodie Modave
- VIB Center for Cancer Biology, B-3000, Leuven, Belgium
- Laboratory of Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | | | - Karen Beets
- Oxurion NV, Gaston Geenslaan 1, B-3001, Leuven, Belgium
| | | | | | - Diether Lambrechts
- VIB Center for Cancer Biology, B-3000, Leuven, Belgium
- Laboratory of Translational Genetics, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Lieve Moons
- Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven, Naamsestraat 61, B-3000, Leuven, Belgium
| | | | - Michaël Porcu
- Oxurion NV, Gaston Geenslaan 1, B-3001, Leuven, Belgium.
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12
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Chen YJ, Chen JT, Tai MC, Liang CM, Chen YY, Chen WL. Serum Iron and Risk of Diabetic Retinopathy. Nutrients 2020; 12:nu12082297. [PMID: 32751778 PMCID: PMC7469039 DOI: 10.3390/nu12082297] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/25/2020] [Accepted: 07/29/2020] [Indexed: 12/16/2022] Open
Abstract
Background: Diabetic retinopathy (DR) is indicated as a major cause of blindness in the world. Emerging evidence supports the interaction of iron metabolism with diabetes. However, little research is available concerning the relationship between iron metabolism and DR. The intent of this paper is to describe the correlation between serum iron and the occurrence of DR. Methods: A total of 5321 participants who underwent related examinations as part of the National Health and Nutrition Examination Survey (2005–2008) were included. DR was defined by the criteria of the Early Treatment for Diabetic Retinopathy Study based on nonmydriatic fundus photography. The cutoff point of serum iron for DR was explored by the receiver operating characteristics curve. The relationship of serum iron with the occurrence of DR was explored by multivariate logistic regression models. Results: Participants with DR had significantly lower serum iron than the control group. Serum iron was negatively correlated with the occurrence of DR after the adjustment of pertinent variables (an odds ratio (OR) of 0.995 (95% CI: 0.992–0.999)). After dividing serum iron into quartiles, the third quartile was associated with DR with an OR of 0.601 (95% CI: 0.418–0.863). Furthermore, the cutoff point of serum iron had an inverse relationship for the occurrence of DR with an OR of 0.766 (95% CI: 0.597–0.984). Conclusion: Serum iron has an inverse association with the occurrence of DR in diabetic adults. The assessment of serum iron levels might be a part of follow-up visits with diabetic patients.
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Affiliation(s)
- Ying-Jen Chen
- Department of Ophthalmology, Tri-Service General Hospital, and School of Medicine, National Defense Medical Center, Taipei 114, Taiwan; (Y.-J.C.); (J.-T.C.); (M.-C.T.); (C.-M.L.)
| | - Jiann-Torng Chen
- Department of Ophthalmology, Tri-Service General Hospital, and School of Medicine, National Defense Medical Center, Taipei 114, Taiwan; (Y.-J.C.); (J.-T.C.); (M.-C.T.); (C.-M.L.)
| | - Ming-Cheng Tai
- Department of Ophthalmology, Tri-Service General Hospital, and School of Medicine, National Defense Medical Center, Taipei 114, Taiwan; (Y.-J.C.); (J.-T.C.); (M.-C.T.); (C.-M.L.)
| | - Chang-Min Liang
- Department of Ophthalmology, Tri-Service General Hospital, and School of Medicine, National Defense Medical Center, Taipei 114, Taiwan; (Y.-J.C.); (J.-T.C.); (M.-C.T.); (C.-M.L.)
| | - Yuan-Yuei Chen
- Department of Pathology, Tri-Service General Hospital Songshan Branch, and School of Medicine, National Defense Medical Center, Taipei 114, Taiwan;
- Department of Pathology, Tri-Service General Hospital, and School of Medicine, National Defense Medical Center, Taipei 114, Taiwan
| | - Wei-Liang Chen
- Division of Geriatric Medicine, Department of Family and Community Medicine, Tri-Service General Hospital, and School of Medicine, National Defense Medical Center, Taipei 114, Taiwan
- Division of Environmental Health & Occupational Medicine, Department of Family & Community Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan
- Department of Biochemistry, National Defense Medical Center, Taipei 114, Taiwan
- Correspondence: ; Tel.: +886-2-87923311 (ext. 16567); Fax: +886-2-87927057
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Picard E, Daruich A, Youale J, Courtois Y, Behar-Cohen F. From Rust to Quantum Biology: The Role of Iron in Retina Physiopathology. Cells 2020; 9:cells9030705. [PMID: 32183063 PMCID: PMC7140613 DOI: 10.3390/cells9030705] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/07/2020] [Accepted: 03/09/2020] [Indexed: 12/24/2022] Open
Abstract
Iron is essential for cell survival and function. It is a transition metal, that could change its oxidation state from Fe2+ to Fe3+ involving an electron transfer, the key of vital functions but also organ dysfunctions. The goal of this review is to illustrate the primordial role of iron and local iron homeostasis in retinal physiology and vision, as well as the pathological consequences of iron excess in animal models of retinal degeneration and in human retinal diseases. We summarize evidence of the potential therapeutic effect of iron chelation in retinal diseases and especially the interest of transferrin, a ubiquitous endogenous iron-binding protein, having the ability to treat or delay degenerative retinal diseases.
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Affiliation(s)
- Emilie Picard
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, USPC, Université Paris Descartes, Team 17, F-75006 Paris, France; (A.D.); (J.Y.); (Y.C.); (F.B.-C.)
- Correspondence: ; Tel.: +331-44-27-81-82
| | - Alejandra Daruich
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, USPC, Université Paris Descartes, Team 17, F-75006 Paris, France; (A.D.); (J.Y.); (Y.C.); (F.B.-C.)
- Ophthalmology Department, Necker-Enfants Malades University Hospital, APHP, 75015 Paris, France
| | - Jenny Youale
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, USPC, Université Paris Descartes, Team 17, F-75006 Paris, France; (A.D.); (J.Y.); (Y.C.); (F.B.-C.)
| | - Yves Courtois
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, USPC, Université Paris Descartes, Team 17, F-75006 Paris, France; (A.D.); (J.Y.); (Y.C.); (F.B.-C.)
| | - Francine Behar-Cohen
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, USPC, Université Paris Descartes, Team 17, F-75006 Paris, France; (A.D.); (J.Y.); (Y.C.); (F.B.-C.)
- Ophtalmopole, Cochin Hospital, AP-HP, Assistance Publique Hôpitaux de Paris, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
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14
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Association of neutrophil-gelatinase-associated lipocalin with microvascular complications in patients with type 2 diabetes: a cross-sectional study. Cardiovasc Endocrinol Metab 2019; 8:82-87. [PMID: 31646302 DOI: 10.1097/xce.0000000000000180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 08/12/2019] [Indexed: 11/25/2022]
Abstract
Diabetic nephropathy and diabetic retinopathy are serious microvascular complications of diabetes mellitus. Recent studies have demonstrated that neutrophil-gelatinase-associated lipocalin (NGAL) may be accompanied by these complications during and before the appearance of microalbuminuria. In this study, we set out to research the role of NGAL in patients with diabetic nephropathy and diabetic retinopathy. Material and methods Eighty-two patients with type 2 diabetes were enrolled in our study. Urinary microalbumine and NGAL levels were measured in urine samples over 24 hours. We also studied NGAL levels in serum. All patients went through an ophthalmologic examination. The results were evaluated based on the presence of microalbuminuria and retinopathy. Results There were no significant differences in serum and urine NGAL levels between normoalbuminuric (n = 66) and microalbuminuric (n = 16) patients. We also did not find any significant difference in patients with retinopathy (n = 16) or without retinopathy (n = 66). Conclusion There are controversial findings about the role of NGAL in diabetic patients in medical literature. Standard values of urine and serum NGAL levels have yet to be determined. Our study suggests that NGAL is not a useful marker to differentiate microalbuminuric patients from normoalbuminuric subjects. We also did not find a relationship between NGAL levels and the presence of retinopathy. Additional studies with larger sample sizes will be required to confirm or refute these findings.
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15
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Prion protein modulates glucose homeostasis by altering intracellular iron. Sci Rep 2018; 8:6556. [PMID: 29700330 PMCID: PMC5919926 DOI: 10.1038/s41598-018-24786-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 03/20/2018] [Indexed: 11/08/2022] Open
Abstract
The prion protein (PrPC), a mainly neuronal protein, is known to modulate glucose homeostasis in mouse models. We explored the underlying mechanism in mouse models and the human pancreatic β-cell line 1.1B4. We report expression of PrPC on mouse pancreatic β-cells, where it promoted uptake of iron through divalent-metal-transporters. Accordingly, pancreatic iron stores in PrP knockout mice (PrP-/-) were significantly lower than wild type (PrP+/+) controls. Silencing of PrPC in 1.1B4 cells resulted in significant depletion of intracellular (IC) iron, and remarkably, upregulation of glucose transporter GLUT2 and insulin. Iron overloading, on the other hand, resulted in downregulation of GLUT2 and insulin in a PrPC-dependent manner. Similar observations were noted in the brain, liver, and neuroretina of iron overloaded PrP+/+ but not PrP-/- mice, indicating PrPC-mediated modulation of insulin and glucose homeostasis through iron. Peripheral challenge with glucose and insulin revealed blunting of the response in iron-overloaded PrP+/+ relative to PrP-/- mice, suggesting that PrPC-mediated modulation of IC iron influences both secretion and sensitivity of peripheral organs to insulin. These observations have implications for Alzheimer's disease and diabetic retinopathy, known complications of type-2-diabetes associated with brain and ocular iron-dyshomeostasis.
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16
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Chaudhary K, Promsote W, Ananth S, Veeranan-Karmegam R, Tawfik A, Arjunan P, Martin P, Smith SB, Thangaraju M, Kisselev O, Ganapathy V, Gnana-Prakasam JP. Iron Overload Accelerates the Progression of Diabetic Retinopathy in Association with Increased Retinal Renin Expression. Sci Rep 2018; 8:3025. [PMID: 29445185 PMCID: PMC5813018 DOI: 10.1038/s41598-018-21276-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 01/31/2018] [Indexed: 12/31/2022] Open
Abstract
Diabetic retinopathy (DR) is a leading cause of blindness among working-age adults. Increased iron accumulation is associated with several degenerative diseases. However, there are no reports on the status of retinal iron or its implications in the pathogenesis of DR. In the present study, we found that retinas of type-1 and type-2 mouse models of diabetes have increased iron accumulation compared to non-diabetic retinas. We found similar iron accumulation in postmortem retinal samples from human diabetic patients. Further, we induced diabetes in HFE knockout (KO) mice model of genetic iron overload to understand the role of iron in the pathogenesis of DR. We found increased neuronal cell death, vascular alterations and loss of retinal barrier integrity in diabetic HFE KO mice compared to diabetic wildtype mice. Diabetic HFE KO mouse retinas also exhibited increased expression of inflammation and oxidative stress markers. Severity in the pathogenesis of DR in HFE KO mice was accompanied by increase in retinal renin expression mediated by G-protein-coupled succinate receptor GPR91. In light of previous reports implicating retinal renin-angiotensin system in DR pathogenesis, our results reveal a novel relationship between diabetes, iron and renin-angiotensin system, thereby unraveling new therapeutic targets for the treatment of DR.
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Affiliation(s)
- Kapil Chaudhary
- Department of Medicine, Washington University, St. Louis, Missouri, USA
| | | | - Sudha Ananth
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Rajalakshmi Veeranan-Karmegam
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Amany Tawfik
- Dental College of Georgia, Augusta University, Augusta, Georgia, USA
| | | | - Pamela Martin
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Sylvia B Smith
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Muthusamy Thangaraju
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Oleg Kisselev
- Department of Ophthalmology and Department of Biochemistry & Molecular Biology, Saint Louis University, St. Louis, Missouri, USA
| | - Vadivel Ganapathy
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Jaya P Gnana-Prakasam
- Department of Ophthalmology and Department of Biochemistry & Molecular Biology, Saint Louis University, St. Louis, Missouri, USA.
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17
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Ambachew S, Biadgo B. Hepcidin in Iron Homeostasis: Diagnostic and Therapeutic Implications in Type 2 Diabetes Mellitus Patients. Acta Haematol 2017; 138:183-193. [PMID: 29136618 DOI: 10.1159/000481391] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 09/08/2017] [Indexed: 12/21/2022]
Abstract
The prevalence of type 2 diabetes is increasing in epidemic proportions worldwide. Evidence suggests body iron overload is frequently linked and observed in patients with type 2 diabetes. Body iron metabolism is based on iron conservation and recycling by which only a part of the daily need is replaced by duodenal absorption. The principal liver-produced peptide called hepcidin plays a fundamental role in iron metabolism. It directly binds to ferroportin, the sole iron exporter, resulting in the internalization and degradation of ferroportin. However, inappropriate production of hepcidin has been shown to play a role in the pathogenesis of type 2 diabetes mellitus and its complications, based on the regulation and expression in iron-abundant cells. Underexpression of hepcidin results in body iron overload, which triggers the production of reactive oxygen species simultaneously thought to play a major role in diabetes pathogenesis mediated both by β-cell failure and insulin resistance. Increased hepcidin expression results in increased intracellular sequestration of iron, and is associated with the complications of type 2 diabetes. Besides, hepcidin concentrations have been linked to inflammatory cytokines, matriptase 2, and chronic hepatitis C infection, which have in turn been reported to be associated with diabetes by several approaches. Either hepcidin-targeted therapy alone or as adjunctive therapy with phlebotomy, iron chelators, or dietary iron restriction may be able to alter iron parameters in diabetic patients. Therefore, measuring hepcidin may improve differential diagnosis and the monitoring of disorders of iron metabolism.
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Affiliation(s)
- Sintayehu Ambachew
- Department of Clinical Chemistry, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
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18
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Baumann B, Sterling J, Song Y, Song D, Fruttiger M, Gillies M, Shen W, Dunaief JL. Conditional Müller Cell Ablation Leads to Retinal Iron Accumulation. Invest Ophthalmol Vis Sci 2017; 58:4223-4234. [PMID: 28846772 PMCID: PMC5574447 DOI: 10.1167/iovs.17-21743] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 07/07/2017] [Indexed: 12/25/2022] Open
Abstract
Purpose Retinal iron accumulation is observed in a wide range of retinal degenerative diseases, including AMD. Previous work suggests that Müller glial cells may be important mediators of retinal iron transport, distribution, and regulation. A transgenic model of Müller cell loss recently demonstrated that primary Müller cell ablation leads to blood-retinal barrier leakage and photoreceptor degeneration, and it recapitulates clinical features observed in macular telangiectasia type 2 (MacTel2), a rare human disease that features Müller cell loss. We used this mouse model to determine the effect of Müller cell loss on retinal iron homeostasis. Methods Changes in total retinal iron levels after Müller cell ablation were measured using inductively coupled plasma mass spectrometry. Corresponding changes in the expression of iron flux and iron storage proteins were determined using quantitative PCR, Western analysis, and immunohistochemistry. Results Müller cell loss led to blood-retinal barrier breakdown and increased iron levels throughout the neurosensory retina. There were corresponding changes in mRNA and/or protein levels of ferritin, transferrin receptor, ferroportin, Zip8, and Zip14. There were also increased iron levels within the RPE of retinal sections from a patient with MacTel2 and both RPE and neurosensory retina of a patient with diabetic retinopathy, which, like MacTel2, causes retinal vascular leakage. Conclusion This study shows that Müller cells and the blood-retinal barrier play pivotal roles in the regulation of retinal iron homeostasis. The retinal iron accumulation resulting from blood-retinal barrier dysfunction may contribute to retinal degeneration in this model and in diseases such as MacTel2 and diabetic retinopathy.
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Affiliation(s)
- Bailey Baumann
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Jacob Sterling
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Ying Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Delu Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Marcus Fruttiger
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Mark Gillies
- Save Sight Institute, The University of Sydney, Sydney, Australia
| | - Weiyong Shen
- Save Sight Institute, The University of Sydney, Sydney, Australia
| | - Joshua L. Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
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19
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Nano-sized iron particles may induce multiple pathways of cell death following generation of mistranscripted RNA in human corneal epithelial cells. Toxicol In Vitro 2017; 42:348-357. [PMID: 28483490 DOI: 10.1016/j.tiv.2017.04.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 03/14/2017] [Accepted: 04/27/2017] [Indexed: 01/08/2023]
Abstract
Iron is closely associated with an ambient particulate matters-induced inflammatory response, and the cornea that covers the front of the eye, is among tissues exposed directly to ambient particulate matters. Prior to this study, we confirmed that nano-sized iron particles (FeNPs) can penetrate the cornea. Thus, we identified the toxic mechanism of FeNPs using human corneal epithelial cells. At 24h after exposure, FeNPs located inside autophagosome-like vacuoles or freely within human corneal epithelial cells. Level of inflammatory mediators including nitric oxide, cytokines, and a chemokine was notably elevated accompanied by the increased generation of reactive oxygen species. Additionally, cell proliferation dose-dependently decreased, and level of multiple pathways of cell death-related indicators was clearly altered following exposure to FeNPs. Furthermore, expression of gene encoding DNA binding protein inhibitor (1, 2, and 3), which are correlated to inhibition of the binding of mistranscripted RNA, was significantly down-regulated. More importantly, expression of p-Akt and caspase-3 and conversion to LC3B-II from LC3B-I was enhanced by pretreatment with a caspase-1 inhibitor. Taken together, we suggest that FeNPs may induce multiple pathways of cell death via generation of mistranscripted RNA, and these cell death pathways may influence by cross-talk. Furthermore, we propose the need of further study for the possibility of tumorigenesis following exposure to FeNPs.
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20
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Nutrition for diabetic retinopathy: plummeting the inevitable threat of diabetic vision loss. Eur J Nutr 2017; 56:2013-2027. [PMID: 28258307 DOI: 10.1007/s00394-017-1406-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 02/10/2017] [Indexed: 12/14/2022]
Abstract
Diabetic retinopathy (DR) is among the leading causes of preventable blindness. Hyperglycemia, hypertension, hyperlipidemia and anemia majorly predispose its pathogenesis. The current treatment modalities of DR include laser photocoagulation therapy, intravitreal corticosteroids, intravitreal anti-vascular endothelial growth factor (VEGF) agents and vitreo-retinal surgery which are costly, highly invasive, unproven for prolonged use and opted in advanced stages of DR. By then retina already encounters a vast damage. Nutrients by their natural physiological, biochemical and molecular action can preserve retinal structure and functions by interfering with the various pathological steps prompting DR incidence, thereby altering the risk of developing this ocular morbidity. Nutrients can also play a central role in DR patients resistant towards the conventional medical treatments. However due to the byzantine interplay existing between nutrients and DR, the worth of nutrition in curbing this vision-threatening ocular morbidity remains silent. This review highlights how nutrients can halt DR development. A nutritional therapy, if adopted in the initial stages, can provide superior-efficacy over the current treatment modalities and can be a complementary, inexpensive, readily available, anodyne option to the clinically unmet requirement for preventing DR. Assessment of nutritional status is presently considered relevant in various clinical conditions except DR. Body Mass Index (BMI) conferred inconclusive results in DR subjects. Subjective Global Assessment (SGA) of nutritional status has recently furnished relevant association with DR status. By integrating nutritional strategies, the risk of developing DR can be reduced substantially. This review summarizes the subsisting knowledge on nutrition, potentially beneficial for preventing DR and sustaining good vision among diabetic subjects.
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Chung JO, Park SY, Cho DH, Chung DJ, Chung MY. Plasma neutrophil gelatinase-associated lipocalin levels are positively associated with diabetic retinopathy in patients with Type 2 diabetes. Diabet Med 2016; 33:1649-1654. [PMID: 27100138 DOI: 10.1111/dme.13141] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/19/2016] [Indexed: 11/30/2022]
Abstract
AIM To assess the relationship between plasma neutrophil gelatinase-associated lipocalin (NGAL) levels and diabetic retinopathy in patients with Type 2 diabetes. METHODS In total, 204 patients with Type 2 diabetes were investigated in this cross-sectional study. They were classified as having no diabetic retinopathy, non-proliferative diabetic retinopathy (NPDR) or proliferative retinopathy (PDR), according to the degree of diabetic retinopathy. Thus, diabetic retinopathy in the patients in this study was either NPDR or PDR. RESULTS Plasma NGAL concentrations were significantly higher in patients with diabetic retinopathy than in those without. The mean plasma NGAL levels differed significantly according to the severity of diabetic retinopathy (no diabetic retinopathy, 120.8 ng/ml; NPDR, 217.8 ng/ml; PDR, 372.4 ng/ml; P for trend = 0.002) after adjustment for other covariates. In multivariable analysis, plasma NGAL levels were significantly associated with diabetic retinopathy (odds ratio for each standard deviation increase in the logarithmic value, 7.75; 95% confidence interval, 2.04-29.41, P = 0.003). CONCLUSION Plasma NGAL levels were positively associated with diabetic retinopathy in patients with Type 2 diabetes.
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Affiliation(s)
- J O Chung
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - S Y Park
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - D H Cho
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - D J Chung
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - M Y Chung
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
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22
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Arjunan P, Gnanaprakasam JP, Ananth S, Romej MA, Rajalakshmi VK, Prasad PD, Martin PM, Gurusamy M, Thangaraju M, Bhutia YD, Ganapathy V. Increased Retinal Expression of the Pro-Angiogenic Receptor GPR91 via BMP6 in a Mouse Model of Juvenile Hemochromatosis. Invest Ophthalmol Vis Sci 2016; 57:1612-9. [PMID: 27046124 PMCID: PMC4824383 DOI: 10.1167/iovs.15-17437] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Hemochromatosis, an iron-overload disease, occurs as adult and juvenile types. Mutations in hemojuvelin (HJV), an iron-regulatory protein and a bone morphogenetic protein (BMP) coreceptor, underlie most of the juvenile type. Hjv(-/-) mice accumulate excess iron in retina and exhibit aberrant vascularization and angiomas. A succinate receptor, GPR91, is pro-angiogenic in retina. We hypothesized that Hjv(-/-) retinas have increased BMP signaling and increased GPR91 expression as the basis of angiomas. METHODS Expression of GPR91 was examined by qPCR, immunofluorescence, and Western blot in wild-type and Hjv(-/-) mouse retinas and pRPE cells. Influence of excess iron and BMP6 on GPR91 expression was investigated in ARPE-19 cells, and wild-type and Hjv(-/-) pRPE cells. Succinate was used to activate GPR91 and determine the effects of GPR91 signaling on VEGF expression. Signaling of BMP6 was studied by the expression of Smad1/5/8 and pSmad4, and the BMP-target gene Id1. The interaction of pSmad4 with GPR91 promoter was studied by ChIP. RESULTS Expression of GPR91 was higher in Hjv(-/-) retinas and RPE than in wild-type counterparts. Unexpectedly, BMP signaling was increased, not decreased, in Hjv(-/-) retinas and RPE. Bone morphogenetic protein 6 induced GPR91 in RPE, suggesting that increased BMP signaling in Hjv(-/-) retinas was likely responsible for GPR91 upregulation. Exposure of RPE to excess iron and succinate as well as BMP6 and succinate increased VEGF expression. Bone morphogenetic protein 6 promoted the interaction of pSmad4 with GPR91 promoter in RPE. CONCLUSIONS G-protein-coupled receptor 91 is a BMP6 target and Hjv deletion enhances BMP signaling in retina, thus underscoring a role for excess iron and hemochromatosis in abnormal retinal vascularization.
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Affiliation(s)
- Pachiappan Arjunan
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, Georgia, United States 2Department of Periodontics, Georgia Regents University, Augusta, Georgia, United States
| | - Jaya P Gnanaprakasam
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, Georgia, United States
| | - Sudha Ananth
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, Georgia, United States
| | - Michelle A Romej
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, Georgia, United States
| | | | - Puttur D Prasad
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, Georgia, United States
| | - Pamela M Martin
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, Georgia, United States
| | - Mariappan Gurusamy
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, Georgia, United States
| | - Muthusamy Thangaraju
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, Georgia, United States
| | - Yangzom D Bhutia
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, Georgia, United States 3Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States
| | - Vadivel Ganapathy
- Department of Biochemistry and Molecular Biology, Georgia Regents University, Augusta, Georgia, United States 3Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, United States
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Picard E, Le Rouzic Q, Oudar A, Berdugo M, El Sanharawi M, Andrieu-Soler C, Naud MC, Jonet L, Latour C, Klein C, Galiacy S, Malecaze F, Coppin H, Roth MP, Jeanny JC, Courtois Y, Behar-Cohen F. Targeting iron-mediated retinal degeneration by local delivery of transferrin. Free Radic Biol Med 2015; 89:1105-21. [PMID: 26454080 DOI: 10.1016/j.freeradbiomed.2015.08.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 08/07/2015] [Accepted: 08/10/2015] [Indexed: 12/11/2022]
Abstract
Iron is essential for retinal function but contributes to oxidative stress-mediated degeneration. Iron retinal homeostasis is highly regulated and transferrin (Tf), a potent iron chelator, is endogenously secreted by retinal cells. In this study, therapeutic potential of a local Tf delivery was evaluated in animal models of retinal degeneration. After intravitreal injection, Tf spread rapidly within the retina and accumulated in photoreceptors and retinal pigment epithelium, before reaching the blood circulation. Tf injected in the vitreous prior and, to a lesser extent, after light-induced retinal degeneration, efficiently protected the retina histology and function. We found an association between Tf treatment and the modulation of iron homeostasis resulting in a decrease of iron content and oxidative stress marker. The immunomodulation function of Tf could be seen through a reduction in macrophage/microglial activation as well as modulated inflammation responses. In a mouse model of hemochromatosis, Tf had the capacity to clear abnormal iron accumulation from retinas. And in the slow P23H rat model of retinal degeneration, a sustained release of Tf in the vitreous via non-viral gene therapy efficently slowed-down the photoreceptors death and preserved their function. These results clearly demonstrate the synergistic neuroprotective roles of Tf against retinal degeneration and allow identify Tf as an innovative and not toxic therapy for retinal diseases associated with oxidative stress.
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Affiliation(s)
- Emilie Picard
- INSERM, UMRS 1138, team Behar-Cohen, From physiopathology of ocular diseases to clinical development, Centre de Recherche des Cordeliers, Paris, France; Université Pierre et Marie Curie-Paris 6, Centre de Recherche des Cordeliers UMRS 1138, Paris, France; Université René Descartes, Centre de Recherche des Cordeliers UMRS 1138, Paris, France.
| | - Quentin Le Rouzic
- INSERM, UMRS 1138, team Behar-Cohen, From physiopathology of ocular diseases to clinical development, Centre de Recherche des Cordeliers, Paris, France; Université Pierre et Marie Curie-Paris 6, Centre de Recherche des Cordeliers UMRS 1138, Paris, France; Université René Descartes, Centre de Recherche des Cordeliers UMRS 1138, Paris, France
| | - Antonin Oudar
- INSERM, UMRS 1138, team Behar-Cohen, From physiopathology of ocular diseases to clinical development, Centre de Recherche des Cordeliers, Paris, France; Université Pierre et Marie Curie-Paris 6, Centre de Recherche des Cordeliers UMRS 1138, Paris, France; Université René Descartes, Centre de Recherche des Cordeliers UMRS 1138, Paris, France
| | - Marianne Berdugo
- INSERM, UMRS 1138, team Behar-Cohen, From physiopathology of ocular diseases to clinical development, Centre de Recherche des Cordeliers, Paris, France; Université Pierre et Marie Curie-Paris 6, Centre de Recherche des Cordeliers UMRS 1138, Paris, France; Université René Descartes, Centre de Recherche des Cordeliers UMRS 1138, Paris, France
| | - Mohamed El Sanharawi
- INSERM, UMRS 1138, team Behar-Cohen, From physiopathology of ocular diseases to clinical development, Centre de Recherche des Cordeliers, Paris, France; Université Pierre et Marie Curie-Paris 6, Centre de Recherche des Cordeliers UMRS 1138, Paris, France; Université René Descartes, Centre de Recherche des Cordeliers UMRS 1138, Paris, France
| | - Charlotte Andrieu-Soler
- INSERM, UMRS 1138, team Behar-Cohen, From physiopathology of ocular diseases to clinical development, Centre de Recherche des Cordeliers, Paris, France; Université Pierre et Marie Curie-Paris 6, Centre de Recherche des Cordeliers UMRS 1138, Paris, France; Université René Descartes, Centre de Recherche des Cordeliers UMRS 1138, Paris, France
| | - Marie-Christine Naud
- INSERM, UMRS 1138, team Behar-Cohen, From physiopathology of ocular diseases to clinical development, Centre de Recherche des Cordeliers, Paris, France; Université Pierre et Marie Curie-Paris 6, Centre de Recherche des Cordeliers UMRS 1138, Paris, France; Université René Descartes, Centre de Recherche des Cordeliers UMRS 1138, Paris, France
| | - Laurent Jonet
- INSERM, UMRS 1138, team Behar-Cohen, From physiopathology of ocular diseases to clinical development, Centre de Recherche des Cordeliers, Paris, France; Université Pierre et Marie Curie-Paris 6, Centre de Recherche des Cordeliers UMRS 1138, Paris, France; Université René Descartes, Centre de Recherche des Cordeliers UMRS 1138, Paris, France
| | - Chloé Latour
- INSERM, U1043, Toulouse, France; CNRS, U5282, Toulouse, France; Université de Toulouse, UPS, Centre de Physiopathologie de Toulouse Purpan (CPTP), Toulouse, France
| | - Christophe Klein
- INSERM, U1138, CICC, Université René Descartes Sorbonne Paris Cité, Université Pierre et Marie Curie Paris, Centre de Recherche des Cordeliers, Paris, France
| | - Stéphane Galiacy
- INSERM U563, Centre de Physiopathologie de Toulouse Purpan, Toulouse, France; Department of Ophthalmology, Purpan Hospital, Toulouse, France
| | - François Malecaze
- INSERM U563, Centre de Physiopathologie de Toulouse Purpan, Toulouse, France; Department of Ophthalmology, Purpan Hospital, Toulouse, France
| | - Hélène Coppin
- INSERM, U1043, Toulouse, France; CNRS, U5282, Toulouse, France; Université de Toulouse, UPS, Centre de Physiopathologie de Toulouse Purpan (CPTP), Toulouse, France
| | - Marie-Paule Roth
- INSERM, U1043, Toulouse, France; CNRS, U5282, Toulouse, France; Université de Toulouse, UPS, Centre de Physiopathologie de Toulouse Purpan (CPTP), Toulouse, France
| | - Jean-Claude Jeanny
- INSERM, UMRS 1138, team Behar-Cohen, From physiopathology of ocular diseases to clinical development, Centre de Recherche des Cordeliers, Paris, France; Université Pierre et Marie Curie-Paris 6, Centre de Recherche des Cordeliers UMRS 1138, Paris, France; Université René Descartes, Centre de Recherche des Cordeliers UMRS 1138, Paris, France
| | - Yves Courtois
- INSERM, UMRS 1138, team Behar-Cohen, From physiopathology of ocular diseases to clinical development, Centre de Recherche des Cordeliers, Paris, France; Université Pierre et Marie Curie-Paris 6, Centre de Recherche des Cordeliers UMRS 1138, Paris, France; Université René Descartes, Centre de Recherche des Cordeliers UMRS 1138, Paris, France
| | - Francine Behar-Cohen
- INSERM, UMRS 1138, team Behar-Cohen, From physiopathology of ocular diseases to clinical development, Centre de Recherche des Cordeliers, Paris, France; Université Pierre et Marie Curie-Paris 6, Centre de Recherche des Cordeliers UMRS 1138, Paris, France; Université René Descartes, Centre de Recherche des Cordeliers UMRS 1138, Paris, France; Jules Gonin Ophthalmic Hospital, Lausanne, Switzerland
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Foureaux G, Nogueira BS, Coutinho DCO, Raizada MK, Nogueira JC, Ferreira AJ. Activation of endogenous angiotensin converting enzyme 2 prevents early injuries induced by hyperglycemia in rat retina. ACTA ACUST UNITED AC 2015; 48:1109-14. [PMID: 26421871 PMCID: PMC4661027 DOI: 10.1590/1414-431x20154583] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 04/27/2015] [Indexed: 12/20/2022]
Abstract
Diabetic retinopathy (DR) is a serious complication of diabetes mellitus that may
result in blindness. We evaluated the effects of activation of endogenous angiotensin
converting enzyme (ACE) 2 on the early stages of DR. Rats were administered an
intravenous injection of streptozotocin to induce hyperglycemia. The ACE2 activator
1-[[2-(dimethylamino) ethyl] amino]-4-(hydroxymethyl)-7-[[(4-methylphenyl) sulfonyl]
oxy]-9H-xanthone 9 (XNT) was administered by daily gavage. The death of retinal
ganglion cells (RGC) was evaluated in histological sections, and retinal ACE2,
caspase-3, and vascular endothelial growth factor (VEGF) expressions were analyzed by
immunohistochemistry. XNT treatment increased ACE2 expression in retinas of
hyperglycemic (HG) rats (control: 13.81±2.71 area%; HG: 14.29±4.30 area%; HG+XNT:
26.87±1.86 area%; P<0.05). Importantly, ACE2 activation significantly increased
the RCG number in comparison with HG animals (control: 553.5±14.29; HG: 530.8±10.3
cells; HG+XNT: 575.3±16.5 cells; P<0.05). This effect was accompanied by a
reduction in the expression of caspase-3 in RGC of the HG+XNT group when compared
with untreated HG rats (control: 18.74±1.59; HG: 38.39±3.39 area%; HG+XNT: 27.83±2.80
area%; P<0.05). Treatment with XNT did not alter the VEGF expression in HG animals
(P>0.05). Altogether, these findings indicate that activation of ACE2 reduced the
death of retinal ganglion cells by apoptosis in HG rats.
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Affiliation(s)
- G Foureaux
- Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - B S Nogueira
- Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - D C O Coutinho
- Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - M K Raizada
- Department of Physiology and Functional Genomics, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - J C Nogueira
- Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - A J Ferreira
- Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
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25
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Increased Vitreous Heme Oxygenase Activity is Associated with Proliferative Diabetic Retinopathy. Indian J Clin Biochem 2015. [DOI: 10.1007/s12291-015-0477-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Abstract
Iron can affect the clinical course of several chronic metabolic diseases such as type 2 diabetes, obesity, non-alcoholic fatty liver disease, and atherosclerosis. Iron overload can affect major tissues involved in glucose and lipid metabolism (pancreatic β cells, liver, muscle, and adipose tissue) and organs affected by chronic diabetic complications. Because iron is a potent pro-oxidant, fine-tuned control mechanisms have evolved to regulate entry, recycling, and loss of body iron. These mechanisms include the interplay of iron with transferrin, ferritin, insulin, and hepcidin, as well as with adipokines and proinflammatory molecules. An imbalance of these homoeostatic mechanisms results in systemic and parenchymal siderosis that contributes to organ damage (such as β-cell dysfunction, fibrosis in liver diseases, and atherosclerotic plaque growth and instability). Conversely, iron depletion can exert beneficial effects in patients with iron overload and even in healthy frequent blood donors. Regular assessment of iron balance should be recommended for patients with chronic metabolic diseases, and further research is needed to produce guidelines for the identification of patients who would benefit from iron depletion.
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Affiliation(s)
- José Manuel Fernández-Real
- Department of Diabetes, Endocrinology and Nutrition, Institut d'Investigació Biomédica de Girona, Hospital de Girona 'Doctor Josep Trueta', Girona, Spain; CIBER Fisiopatología de la Obesidad y Nutrición, Girona, Spain.
| | - Melania Manco
- Research Unit for Multifactorial Disease, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy
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Tawfik A, Gnana-Prakasam JP, Smith SB, Ganapathy V. Deletion of hemojuvelin, an iron-regulatory protein, in mice results in abnormal angiogenesis and vasculogenesis in retina along with reactive gliosis. Invest Ophthalmol Vis Sci 2014; 55:3616-25. [PMID: 24812553 DOI: 10.1167/iovs.13-13677] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
PURPOSE Loss-of-function mutations in hemojuvelin (HJV) cause juvenile hemochromatosis, an iron-overload disease. Deletion of Hjv in mice results in excessive iron accumulation and morphologic changes in the retina. Here, we studied the retinal vasculature in Hjv(-/-) mice. METHODS Age-matched wild-type and Hjv(-/-) mice were used for fluorescein angiography and preparation of retinal cryosections, flat-mounts, and trypsin-digested blood vessels. Retinal angiogenesis was monitored by immunofluorescent detection of isolectin-B4, endoglin, and VEGF. Retinal vasculogenesis was monitored by immunofluorescent detection of collagen IV. Reactive gliosis was assessed based on the expression of glial fibrillary acidic protein and vimentin and CD11b/c as markers for Müller cells and microglia. RESULTS Between 18 and 24 months of age, retinas of Hjv(-/-) mice displayed marked disruptions in angiogenesis and vasculogenesis. Blood vessels in Hjv(-/-) mice were tortuous and dilated, with a decrease in the tight-junction protein occludin. There was also evidence of neovascularization in Hjv(-/-) mice with blood vessels appearing in the vitreous, which were leaky. There was reactive gliosis in these mice involving both Müller cells and microglia. Such changes were not detected at 2 weeks of age. Even at the age of 4 months, retinas of Hjv(-/-) mice were almost normal with changes just beginning to appear. Thus, the vascular changes in Hjv(-/-) mouse retinas represent an age-dependent phenomenon. CONCLUSIONS Deletion of Hjv in mice leads to abnormal retinal angiogenesis/vasculogenesis, with proliferation of new, leaky blood vessels in the vitreous. These changes are accompanied with reactive gliosis involving Müller cells and microglia.
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Affiliation(s)
- Amany Tawfik
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States James & Jean Culver Vision Discovery Institute, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States
| | - Jaya P Gnana-Prakasam
- James & Jean Culver Vision Discovery Institute, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States Department of Biochemistry and Molecular Biology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States
| | - Sylvia B Smith
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States James & Jean Culver Vision Discovery Institute, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States
| | - Vadivel Ganapathy
- James & Jean Culver Vision Discovery Institute, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States Department of Biochemistry and Molecular Biology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States
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28
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Guo L, Jiang F, Tang YT, Si MY, Jiao XY. The association of serum vascular endothelial growth factor and ferritin in diabetic microvascular disease. Diabetes Technol Ther 2014; 16:224-34. [PMID: 24279470 PMCID: PMC3952528 DOI: 10.1089/dia.2013.0181] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Vascular endothelial growth factor (VEGF) is involved in the pathogenesis of diabetic microvascular disease. Most diabetes patients have higher serum levels of ferritin that may participate in diabetic vascular complications through high oxidative stress induced by iron. However, the mechanistic link between ferritin and VEGF is obscure. The study investigated the association of VEGF and ferritin in patients with diabetic microvascular disease. PATIENTS AND METHODS Sixty patients with type 2 diabetes mellitus (T2DM) and 26 healthy individuals were selected in this study. Serum ferritin, VEGF, hematological parameters, and clinical data were assessed in this cohort. The Spearman rank method was used to evaluate the associations among them. RESULTS Serum levels of VEGF and ferritin were significantly higher in diabetes patients compared with the controls; levels of both were elevated with development of the disease. There were positive correlations between VEGF and glucose levels and between VEGF and ferritin in diabetes groups, especially in patients with diabetic retinopathy. Positive correlations were also found between VEGF level and the parameters of age, hemoglobin, and albumin in patients with diabetes hypertension. CONCLUSIONS Our data suggest that high ferritin levels in T2DM are closely related to the development of diabetic vascular complications through interaction with VEGF.
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Affiliation(s)
- Li Guo
- Department of Hematology Laboratory, First Affiliated Hospital of Shantou University Medical College , Shantou, Guangdong, China
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29
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Giese MJ, Speth RC. The ocular renin-angiotensin system: a therapeutic target for the treatment of ocular disease. Pharmacol Ther 2013; 142:11-32. [PMID: 24287313 DOI: 10.1016/j.pharmthera.2013.11.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 10/25/2013] [Indexed: 02/06/2023]
Abstract
The renin-angiotensin system (RAS) is most well-known for its role in regulation and dysregulation of blood pressure as well as fluid and electrolyte homeostasis. Due to its ability to cause cardiovascular disease, the RAS is the target of a multitude of drugs that antagonize its pathophysiological effects. While the "classical" RAS is a systemic hormonal system, there is an increasing awareness of the existence and functional significance of local RASs in a number of organs, e.g., liver, kidney, heart, lungs, reproductive organs, adipose tissue and adrenal. The eye is one of these organs where a compelling body of evidence has demonstrated the presence of a local RAS. Individual components of the RAS have been shown to be present in many structures of the eye and their potential functional significance in ocular disease states is described. Because the eye is one of the most important and complex organs in the body, this review also discusses the implications of dysregulation of the systemic RAS on the pathogenesis of ocular diseases and how pharmacological manipulation of the RAS might lead to novel or adjunctive therapies for ocular disease states.
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Affiliation(s)
| | - Robert C Speth
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL 33328, United States.
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Gnana-Prakasam JP, Ananth S, Prasad PD, Zhang M, Atherton SS, Martin PM, Smith SB, Ganapathy V. Expression and iron-dependent regulation of succinate receptor GPR91 in retinal pigment epithelium. Invest Ophthalmol Vis Sci 2011; 52:3751-8. [PMID: 21357408 DOI: 10.1167/iovs.10-6722] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
PURPOSE GPR91, a succinate receptor, is expressed in retinal ganglion cells and induces vascular endothelial growth factor (VEGF) expression. RPE also expresses VEGF, but whether this cell expresses GPR91 is not known. Excessive iron is also proangiogenic, and hemochromatosis is associated with iron overload. Therefore, we examined the expression and iron-dependent regulation of GPR91 in the RPE. METHODS GPR91 expression was examined by RT-PCR and immunohistochemistry. Hemochromatosis mice, cytomegalovirus (CMV) infection of retina, expression of CMV-US2 in RPE, and exposure of RPE to ferric ammonium citrate (FAC) were used to examine the iron-dependent regulation of GPR91 expression. VEGF expression was quantified by qPCR. Knockdown of GPR91 in ARPE-19 cells was achieved with shRNA. RESULTS GPR91 was expressed in RPE but only in the apical membrane. Retinal expression of GPR91 was higher in hemochromatosis (Hfe(-/-)) mice than in wild-type (WT) mice. Primary RPE cells from Hfe(-/-) mice had increased GPR91 expression compared with WT RPE cells. Iron accumulation in cells induced by CMV infection, expression of CMV-US2, or treatment with FAC increased GPR91 expression. VEGF expression in the Hfe(-/-) mouse retina was increased at ages younger than 18 months, but the expression was downregulated at older ages. The involvement of GPR91 in succinate-induced expression of VEGF in RPE cells was confirmed with GPR91-specific shRNA. CONCLUSIONS GPR91 is expressed in the RPE with specific localization to the apical membrane, indicating that succinate in the subretinal space serves as the GPR91 agonist. Excessive iron in the retina and RPE enhances GPR91 expression; however, VEGF expression does not always parallel GPR91 expression.
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Affiliation(s)
- Jaya P Gnana-Prakasam
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta, Georgia 30912, USA
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