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Mrugacz M, Bryl A, Zorena K. Retinal Vascular Endothelial Cell Dysfunction and Neuroretinal Degeneration in Diabetic Patients. J Clin Med 2021; 10:jcm10030458. [PMID: 33504108 PMCID: PMC7866162 DOI: 10.3390/jcm10030458] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/11/2021] [Accepted: 01/19/2021] [Indexed: 12/13/2022] Open
Abstract
Diabetes mellitus (DM) has become a vital societal problem as epidemiological studies demonstrate the increasing incidence of type 1 and type 2 diabetes. Lesions observed in the retina in the course of diabetes, referred to as diabetic retinopathy (DR), are caused by vascular abnormalities and are ischemic in nature. Vascular lesions in diabetes pertain to small vessels (microangiopathy) and involve precapillary arterioles, capillaries and small veins. Pericyte loss, thickening of the basement membrane, and damage and proliferation of endothelial cells are observed. Endothelial cells (monolayer squamous epithelium) form the smooth internal vascular lining indispensable for normal blood flow. Breaking its continuity initiates blood coagulation at that site. The endothelium controls the process of exchange of chemical substances (nutritional, regulatory, waste products) between blood and the retina, and blood cell passing through the vascular wall. Endothelial cells produce biologically active substances involved in blood coagulation, regulating vascular wall tension and stimulating neoangiogenesis. On the other hand, recent studies have demonstrated that diabetic retinopathy may be not only a microvascular disease, but is a result of neuroretinal degeneration. Neuroretinal degeneration appears structurally, as neural apoptosis of amacrine and Muller cells, reactive gliosis, ganglion cell layer/inner plexiform (GCL) thickness, retinal thickness, and retinal nerve fiber layer thickness, and a reduction of the neuroretinal rim in minimum rim width (MRW) and functionally as an abnormal electroretinogram (ERG), dark adaptation, contrast sensitivity, color vision, and microperimetric test. The findings in early stages of diabetic retinopathy may precede microvascular changes of this disease. Furthermore, the article's objective is to characterize the factors and mechanisms conducive to microvascular changes and neuroretinal apoptosis in diabetic retinopathy. Only when all the measures preventing vascular dysfunction are determined will the risk of complications in the course of diabetes be minimized.
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Affiliation(s)
- Malgorzata Mrugacz
- Department of Ophthalmology and Eye Rehabilitation, Medical University of Bialystok, 15-089 Białystok, Poland
| | - Anna Bryl
- Department of Ophthalmology and Eye Rehabilitation, Medical University of Bialystok, 15-089 Białystok, Poland
| | - Katarzyna Zorena
- Department of Immunobiology and Environment Microbiology, Medical University of Gdańsk, 18-211 Gdańsk, Poland
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Saleh I, Maritska Z, Parisa N, Hidayat R. Inhibition of Receptor for Advanced Glycation End Products as New Promising Strategy Treatment in Diabetic Retinopathy. Open Access Maced J Med Sci 2019; 7:3921-3924. [PMID: 32165929 PMCID: PMC7061394 DOI: 10.3889/oamjms.2019.759] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 10/01/2019] [Accepted: 10/02/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Extensive intracellular and extracellular formation of advanced glycation end-products (AGEs) is considered a causative factor for vascular injury triggered by hyperglycemia in diabetes. The hyperglycemia will cause accumulation of AGEs, damage to pericytes, nerve growth factor (NGF), glial acid fibrillary protein (GFAP) and increase in vascular endothelial growth factor (VEGF). AIM This study aimed to assess the efficacy of RAGE inhibition in suppressing the development and progression of diabetic retinopathy through modulation of the inflammatory pathway involving NGF, GFAP, and VEGF. METHODS The design was in vivo experimental study. Thirty white rats were induced with Alloxan monohydrate. Rats were divided into 5 groups, normal, negative control, groups with an anti-RAGE dose of 1 μg/uL, the dose of 10 μg/uL and 100 μg/uL. After 4 weeks of treatment, HbA1c, NGF, and GFAP levels were measured using ELISA. Quantification of VEGF expression was done using the ImageJ® application. Data was expressed with mean ± SD. Independent T-test with ANOVA and Tukey's post hoc was done. RESULTS RAGE inhibitors yielded a significant decrease in blood glucose and HbA1c levels. VEGF and RAGE expression were reduced in anti-RAGE groups in various doses. Inhibition of RAGE reduced the damage of retinal pericytes, by reducing GFAP and increasing NGF, and reduced the formation of new blood vessels, by decreasing VEGF expression, in diabetic retinopathy. CONCLUSION Inhibition of receptor for advanced glycation end-products (RAGE) was effective in suppressing the development and progression of diabetic retinopathy.
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Affiliation(s)
- Irsan Saleh
- Department of Pharmacology, Faculty of Medicine, Universitas Sriwijaya, Palembang, Indonesia
| | - Ziske Maritska
- Department of Biology, Faculty of Medicine, Universitas Sriwijaya, Palembang, Indonesia
| | - Nita Parisa
- Department of Pharmacology, Faculty of Medicine, Universitas Sriwijaya, Palembang, Indonesia
| | - Rachmat Hidayat
- Department of Biology, Faculty of Medicine, Universitas Sriwijaya, Palembang, Indonesia
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Broadgate S, Kiire C, Halford S, Chong V. Diabetic macular oedema: under-represented in the genetic analysis of diabetic retinopathy. Acta Ophthalmol 2018; 96 Suppl A111:1-51. [PMID: 29682912 DOI: 10.1111/aos.13678] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 11/21/2017] [Indexed: 12/15/2022]
Abstract
Diabetic retinopathy, a complication of both type 1 and type 2 diabetes, is a complex disease and is one of the leading causes of blindness in adults worldwide. It can be divided into distinct subclasses, one of which is diabetic macular oedema. Diabetic macular oedema can occur at any time in diabetic retinopathy and is the most common cause of vision loss in patients with type 2 diabetes. The purpose of this review is to summarize the large number of genetic association studies that have been performed in cohorts of patients with type 2 diabetes and published in English-language journals up to February 2017. Many of these studies have produced positive associations with gene polymorphisms and diabetic retinopathy. However, this review highlights that within this large body of work, studies specifically addressing a genetic association with diabetic macular oedema, although present, are vastly under-represented. We also highlight that many of the studies have small patient numbers and that meta-analyses often inappropriately combine patient data sets. We conclude that there will continue to be conflicting results and no meaningful findings will be achieved if the historical approach of combining all diabetic retinopathy disease states within patient cohorts continues in future studies. This review also identifies several genes that would be interesting to analyse in large, well-defined cohorts of patients with diabetic macular oedema in future candidate gene association studies.
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Affiliation(s)
- Suzanne Broadgate
- Nuffield Laboratory of Ophthalmology; Nuffield Department of Clinical Neurosciences; University of Oxford; Oxford UK
| | - Christine Kiire
- Nuffield Laboratory of Ophthalmology; Nuffield Department of Clinical Neurosciences; University of Oxford; Oxford UK
- Oxford Eye Hospital; John Radcliffe Hospital; Oxford University NHS Foundation Trust; Oxford UK
| | - Stephanie Halford
- Nuffield Laboratory of Ophthalmology; Nuffield Department of Clinical Neurosciences; University of Oxford; Oxford UK
| | - Victor Chong
- Nuffield Laboratory of Ophthalmology; Nuffield Department of Clinical Neurosciences; University of Oxford; Oxford UK
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Pradhan P, Upadhyay N, Tiwari A, Singh LP. Genetic and epigenetic modifications in the pathogenesis of diabetic retinopathy: a molecular link to regulate gene expression. ACTA ACUST UNITED AC 2016; 2:192-204. [PMID: 28691104 DOI: 10.15761/nfo.1000145] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intensification in the frequency of diabetes and the associated vascular complications has been a root cause of blindness and visual impairment worldwide. One such vascular complication which has been the prominent cause of blindness; retinal vasculature, neuronal and glial abnormalities is diabetic retinopathy (DR), a chronic complicated outcome of Type 1 and Type 2 diabetes. It has also become clear that "genetic" variations in population alone can't explain the development and progression of diabetes and its complications including DR. DR experiences engagement of foremost mediators of diabetes such as hyperglycemia, oxidant stress, and inflammatory factors that lead to the dysregulation of "epigenetic" mechanisms involving histone acetylation and histone and DNA methylation, chromatin remodeling and expression of a complex set of stress-regulated and disease-associated genes. In addition, both elevated glucose concentration and insulin resistance leave a robust effect on epigenetic reprogramming of the endothelial cells too, since endothelium associated with the eye aids in maintaining the vascular homeostasis. Furthermore, several studies conducted on the disease suggest that the modifications of the epigenome might be the fundamental mechanism(s) for the proposed metabolic memory' resulting into prolonged gene expression for inflammation and cellular dysfunction even after attaining the glycemic control in diabetics. Henceforth, the present review focuses on the aspects of genetic and epigenetic alterations in genes such as vascular endothelial growth factor and aldose reductase considered being associated with DR. In addition, we discuss briefly the role of the thioredoxin-interacting protein TXNIP, which is strongly induced by high glucose and diabetes, in cellular oxidative stress and mitochondrial dysfunction potentially leading to chromatin remodeling and ocular complications of diabetes. The identification of disease-associated genes and their epigenetic regulations will lead to potential new drugs and gene therapies as well as personalized medicine to prevent or slow down the progression of DR.
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Affiliation(s)
- Priya Pradhan
- School of Biotechnology, Rajiv Gandhi Technical University, Bhopal, Madhya Pradesh, India
| | - Nisha Upadhyay
- School of Biotechnology, Rajiv Gandhi Technical University, Bhopal, Madhya Pradesh, India
| | - Archana Tiwari
- School of Biotechnology, Rajiv Gandhi Technical University, Bhopal, Madhya Pradesh, India
| | - Lalit P Singh
- Departments of Anatomy/Cell Biology and Ophthalmology, School of Medicine, Wayne State University, Detroit, MI, USA
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Priščáková P, Minárik G, Repiská V. Candidate gene studies of diabetic retinopathy in human. Mol Biol Rep 2016; 43:1327-1345. [PMID: 27730450 PMCID: PMC5102952 DOI: 10.1007/s11033-016-4075-y] [Citation(s) in RCA: 33] [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: 01/22/2016] [Accepted: 09/09/2016] [Indexed: 12/13/2022]
Abstract
Diabetic retinopathy (DR) is a multifactorial disease with complex pathophysiology. It is the main cause of blindness among the people in productive age. The purpose of this literature review is to highlight recent achievements in the genetics of diabetic retinopathy with particular focus on candidate gene studies. We summarized most of the available published data about candidate genes for diabetic retinopathy with the goal to identify main genetic aspects. We conclude that genetic studies reported contradictory findings and no genetic variants meet criteria of a diagnostic marker, or significantly elucidate the root of DR development. Based on these findings it is important to continue with the research in the field of DR genetics, mainly due to the fact that currently new possibilities and approaches associated with utilization of next-generation sequencing are available.
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Affiliation(s)
- Petra Priščáková
- Faculty of Medicine, Institute of Medical Biology, Genetics and Clinical Genetics, University Hospital Bratislava, Comenius University in Bratislava, Sasinkova 4, 81108, Bratislava, Slovakia
| | - Gabriel Minárik
- Medirex Group Academy n.o., Galvaniho 17/C, 82016, Bratislava, Slovakia
| | - Vanda Repiská
- Faculty of Medicine, Institute of Medical Biology, Genetics and Clinical Genetics, University Hospital Bratislava, Comenius University in Bratislava, Sasinkova 4, 81108, Bratislava, Slovakia.
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He K, Lv W, Zhang Q, Wang Y, Tao L, Liu D. Gene set enrichment analysis of pathways and transcription factors associated with diabetic retinopathy using a microarray dataset. Int J Mol Med 2015; 36:103-12. [PMID: 25997411 PMCID: PMC4494587 DOI: 10.3892/ijmm.2015.2220] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/12/2015] [Indexed: 01/05/2023] Open
Abstract
Diabetic retinopathy (DR) is a serious microvascular complication of diabetes, which causes visual disability and blindness. Several studies have used gene expression profiling of DR to identify the key genes involved in this process; however, few studies have focused on the associated pathways and transcription factors (TFs), or on the co-expression patterns at the multiple pathways level. In this study, we employed a microarray dataset from the public database library of the Gene Expression Omnibus (GEO) associated with DR and applied gene set enrichment analysis (GSEA) to this dataset and performed candidate TF selection. As a result, 10 upregulated pathways, including the type I diabetes mellitus and peroxisome proliferator-activated receptor (PPAR) signaling pathways, as well as 59 downregulated pathways, including the ErbB signaling pathway and the mammalian target of rapamycin (mTOR) signaling pathway, were identified as DR‑related pathways. The majority of these pathways have been previously identified, but some were novel. Finally, co-expression networks of related pathways were constructed using the significant core genes and TFs, such as PPARγ and SMAD4. The results of our study may enhance our understanding of the molecular mechanisms associated DR at the genome-wide level.
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Affiliation(s)
- Kan He
- Center for Stem Cell and Translational Medicine, School of Life Sciences, Anhui University, Hefei, Anhui 230601, P.R. China
| | - Wenwen Lv
- Center for Stem Cell and Translational Medicine, School of Life Sciences, Anhui University, Hefei, Anhui 230601, P.R. China
| | - Qing Zhang
- Department of Ophthalmology, The Second Hospital of Anhui Medical University, Hefei, Anhui 230601, P.R. China
| | - Yuqing Wang
- Center for Stem Cell and Translational Medicine, School of Life Sciences, Anhui University, Hefei, Anhui 230601, P.R. China
| | - Liming Tao
- Department of Ophthalmology, The Second Hospital of Anhui Medical University, Hefei, Anhui 230601, P.R. China
| | - Dahai Liu
- Center for Stem Cell and Translational Medicine, School of Life Sciences, Anhui University, Hefei, Anhui 230601, P.R. China
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Ferreira FN, Crispim D, Canani LH, Gross JL, dos Santos KG. Association study of sorbitol dehydrogenase -888G>C polymorphism with type 2 diabetic retinopathy in Caucasian-Brazilians. Exp Eye Res 2013; 115:140-3. [PMID: 23850972 DOI: 10.1016/j.exer.2013.06.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 06/27/2013] [Indexed: 11/26/2022]
Abstract
Diabetic retinopathy (DR) is a common chronic complication of diabetes and remains the leading cause of blindness in working-aged people. Hyperglycemia increases glucose flux through the polyol pathway, in which aldose reductase converts glucose into intracellular sorbitol, which is subsequently converted to fructose by sorbitol dehydrogenase (SDH). The accelerated polyol pathway triggers a cascade of events leading to retinal vascular endothelial dysfunction and the eventual development of DR. Polymorphisms in the gene encoding aldose reductase have been consistently associated with DR. However, only two studies have analyzed the relationship between polymorphisms in the gene encoding SDH (SORD) and DR. In this case-control study, we investigated whether the -888G > C polymorphism (rs3759890) in the SORD gene is associated with the presence or severity of DR in 446 Caucasian-Brazilians with type 2 diabetes (241 subjects with and 205 subjects without DR). The -888G > C polymorphism was also examined in 105 healthy Caucasian blood donors, and the genotyping of this polymorphism was carried out by real-time PCR. The genotype and allele frequencies of the -888G > C polymorphism in patients with type 2 diabetes were similar to those of blood donors (G allele frequency = 0.16 in both groups of subjects). Similarly, the genotype and allele frequencies in patients with DR or the proliferative form of DR were similar to those of patients without this complication (P > 0.05 for all comparisons). Thus, our findings suggest that the -888G > C polymorphism in the SORD gene is not involved in the pathogenesis of DR in type 2 diabetes.
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Affiliation(s)
- Fábio Netto Ferreira
- Laboratory of Human Molecular Genetics, Universidade Luterana do Brasil, Canoas, Brazil
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8
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Tarr JM, Kaul K, Chopra M, Kohner EM, Chibber R. Pathophysiology of diabetic retinopathy. ISRN OPHTHALMOLOGY 2013; 2013:343560. [PMID: 24563789 PMCID: PMC3914226 DOI: 10.1155/2013/343560] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Accepted: 12/13/2012] [Indexed: 12/13/2022]
Abstract
Diabetes is now regarded as an epidemic, with the population of patients expected to rise to 380 million by 2025. Tragically, this will lead to approximately 4 million people around the world losing their sight from diabetic retinopathy, the leading cause of blindness in patients aged 20 to 74 years. The risk of development and progression of diabetic retinopathy is closely associated with the type and duration of diabetes, blood glucose, blood pressure, and possibly lipids. Although landmark cross-sectional studies have confirmed the strong relationship between chronic hyperglycaemia and the development and progression of diabetic retinopathy, the underlying mechanism of how hyperglycaemia causes retinal microvascular damage remains unclear. Continued research worldwide has focussed on understanding the pathogenic mechanisms with the ultimate goal to prevent DR. The aim of this paper is to introduce the multiple interconnecting biochemical pathways that have been proposed and tested as key contributors in the development of DR, namely, increased polyol pathway, activation of protein kinase C (PKC), increased expression of growth factors such as vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF-1), haemodynamic changes, accelerated formation of advanced glycation endproducts (AGEs), oxidative stress, activation of the renin-angiotensin-aldosterone system (RAAS), and subclinical inflammation and capillary occlusion. New pharmacological therapies based on some of these underlying pathogenic mechanisms are also discussed.
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Affiliation(s)
| | | | | | | | - Rakesh Chibber
- Institute of Biomedical and Clinical Science, Peninsula College of Medicine and Dentistry, University of Exeter, St Luke's Campus, Magdalen Road, Exeter EX1 2LU, UK
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Tarr JM, Kaul K, Wolanska K, Kohner EM, Chibber R. Retinopathy in diabetes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 771:88-106. [PMID: 23393674 DOI: 10.1007/978-1-4614-5441-0_10] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
With the incidence, and prevalence of diabetes mellitus increasing worldwide, diabetic retinopathy is expected to reach epidemic proportions. The aim of this chapter is to introduce diabetic retinopathy, a leading cause of blindness in people of the working age. The clinical course of retinopathy, anatomical changes, its pathogenesis and current treatment are described, followed by an overview of the emerging drug therapies for the potential treatment of this sight-threatening complication of diabetes.
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Affiliation(s)
- Joanna M Tarr
- Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, UK
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10
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Abstract
Since diabetes is now a global epidemic, the incidence of retinopathy, a leading cause of blindness in patients aged 20-74 years, is also expected to rise to alarming levels. The risk of development and progression of diabetic retinopathy is closely associated with the type and duration of diabetes, blood glucose, blood pressure and possibly lipids. It is an unmet medical need that can lead to severe and irreversible loss of vision in people of working age worldwide. The aim of this review is to give an overview of the clinical and anatomical changes during the progression of retinopathy, the underlying pathogenic mechanisms that link hyperglycemia with retinal tissue damage, current treatments, and the emerging pharmacological therapies for this sight-threatening complication of diabetes.
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Affiliation(s)
- Dimitry A Chistiakov
- Department of Molecular Diagnostics, National Research Center GosNIIgenetika, Moscow, Russia.
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11
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Human genetics of diabetic retinopathy: current perspectives. J Ophthalmol 2010; 2010. [PMID: 20706635 PMCID: PMC2913807 DOI: 10.1155/2010/172593] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 06/16/2010] [Indexed: 01/15/2023] Open
Abstract
Diabetic retinopathy (DR) is a most severe microvascular complication which, if left unchecked, can be sight-threatening. With the global prevalence of diabetes being relentlessly projected to rise to 438 million subjects by 2030, DR will undoubtedly pose a major public health concern. Efforts to unravel the human genetics of DR have been undertaken using the candidate gene and linkage approaches, while GWAS efforts are still lacking. Aside from evidence for a few genes including aldose reductase and vascular endothelial growth factor, the genetics of DR remain poorly elucidated. Nevertheless, the promise of impactful scientific discoveries may be realized if concerted and collaborative efforts are mounted to identify the genes for DR. Harnessing new genetic technologies and resources such as the upcoming 1000 Genomes Project will help advance this field of research, and potentially lead to a rich harvest of insights into the biological mechanisms underlying this debilitating complication.
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Landau Z, Novotny MJ, Preston GM, Wright K, Freeman T, Dai H, Thompson J, Oates PJ, Calle RA. Pharmacokinetics, pharmacodynamics, tolerability, and safety of a novel sorbitol dehydrogenase inhibitor in healthy participants. J Clin Pharmacol 2010; 50:521-30. [PMID: 20220044 DOI: 10.1177/0091270009336354] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Increased glucose flux through the polyol pathway and the resultant oxidative stress is thought to be a major mechanistic contributor to microvascular diabetic complications. Inhibition of flux through this pathway can be blocked through inhibition of either of 2 enzymes, aldose reductase (AR) or sorbitol dehydrogenase (SDH). This report describes the pharmacokinetics, biomarker pharmacodynamics, and safety of CP-642,931, a potent and specific sorbitol dehydrogenase inhibitor (SDI). CP-642,931 was administered for 7 days to 57 healthy volunteers in doses ranging from 1 to 35 mg daily. After the 35-mg dose, CP-642,931 showed a t((1/2)) of 20.1 hours and t(max) at 0.5 to 1.25 hours. After a 35-mg dose, maximum inhibition of SDH was 91% (on days 1 and 7), and maximum serum sorbitol increase was 152-fold on day 7 compared to control. Five participants discontinued the study due to adverse events, including myalgia, muscle spasm, and muscle fatigue. All symptoms resolved in all but 1 participant, who continued to report intermittent muscle fasciculations upon follow-up. In conclusion, CP-642,931 is a potent and specific SDI that is rapidly absorbed through the oral route and effectively inhibits SDH. However, the drug is not well tolerated due to adverse neuromuscular effects.
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Affiliation(s)
- Zohar Landau
- Pfizer Global Research & Development, 50 Pequot Avenue, New London, CT 06320, USA
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13
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Association between sorbitol dehydrogenase gene polymorphisms and type 2 diabetic retinopathy. Exp Eye Res 2008; 86:647-52. [PMID: 18289528 DOI: 10.1016/j.exer.2008.01.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 12/07/2007] [Accepted: 01/08/2008] [Indexed: 11/21/2022]
Abstract
Diabetic retinopathy (DR) may affect 98% of diabetic patients, but its aetiology is poorly understood. Besides glycaemic exposure, genetic factors likely contribute to the onset of DR. The polyol pathway, including aldose reductase and sorbitol dehydrogenase (SDH), can be activated under hyperglycaemic conditions. In our work we searched for an association between the C-1214G and G-888C polymorphisms of the SDH gene promoter and the occurrence and progression of type 2 DR. Two hundred and fifteen unrelated individuals with type 2 diabetes mellitus (T2DM) were divided into three groups: without DR, with non-proliferative diabetic retinopathy (NPDR) and with proliferative diabetic retinopathy (PDR). Genotypes of the C-1214G (rs2055858) and G-888C (rs3759890) polymorphisms of the SDH gene were determined with DNA from the peripheral blood lymphocytes of patients by restriction fragment length polymorphism and allele-specific PCR, respectively. The genotype distributions were contrasted by the chi(2) test and the significance of the polymorphism was assessed by multiple logistic regression producing odds ratios (ORs) and 95% confidence intervals (CIs). We found an association (OR 1.73, 95% CI 1.06-2.83) between NPDR and the G allele of the G-888C polymorphism. There was no association between NPDR and the other polymorphisms of the SDH gene. No differences were found in the distributions of these polymorphisms between patients with PDR and those with NPDR. A weak association (OR 2.0, 95% CI 1.29-3.07) was found between DR and the G allele of the G-888C polymorphism. Analysis of the combined genotypes (haplotypes) of both polymorphisms revealed associations between the C/G-C/G genotype and NPDR (OR 2.95, 95% CI 1.07-8.13) as well as DR in general (OR 2.91, 95% CI 1.15-7.36). The G-888C polymorphism of the SDH gene may be associated with the onset of DR rather than with its progression, and its effect may be strengthened by the interaction with the C-1214G polymorphism, but this association is rather weak and requires further study.
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Abstract
Diabetes is rapidly increasing in frequency with an attendant toll of complications, including diabetic retinopathy. Although the underlying mechanisms remain elusive, genetic susceptibility is key to both types 1 and 2 diabetes and is increasingly recognized for its contribution to diabetic complications. In this article we review the evidence connecting genetic susceptibility to diabetic retinopathy. Elucidating the susceptibility genes and pathways should permit strategies to slow and reverse the troubling trends for the population, families, and individuals.
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Affiliation(s)
- Craig L Hanis
- Human Genetics Center, The University of Texas Health Science Center at Houston, PO Box 20186, Houston, TX 77225, USA.
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Karacaoğlan V, Ozer I. Steady-state kinetic properties of sorbitol dehydrogenase from chicken liver. Comp Biochem Physiol B Biochem Mol Biol 2005; 140:309-12. [PMID: 15649778 DOI: 10.1016/j.cbpc.2004.10.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Revised: 10/25/2004] [Accepted: 10/26/2004] [Indexed: 10/26/2022]
Abstract
The steady-state kinetic properties of partially purified chicken liver sorbitol dehydrogenase (SDH) were determined spectrophotometrically at 25 degrees C, in 50 mM 3-(N-morpholino)propanesulfonic acid (MOPS) buffer, pH 8.0. In the sorbitol-to-fructose direction, analysis was based on initial rate data obtained at [NAD(+)](o)=0.1-0.4 mM and [sorbitol](o)=1.25-10 mM. The reverse process was analyzed by recording progress curves for NADH consumption, starting with [NADH](o)=0.2 mM and [fructose](o)=66.7-267 mM. The kinetics conformed to an ordered sequential model, with the cofactors adding first. The steady-state parameters in the forward direction, K(NAD(+)), K(iNAD(+)) and K(sorbitol), were found to be 210+/-62 muM, 220+/-69 microM and 3.2+/-0.54 mM, respectively. The corresponding parameters in the reverse direction were K(NADH)=240+/-58 microM, K(iNADH)=10+/-2.8 microM and K(fructose)=1000+/-140 mM. The results indicated a close parallelism with human SDH, yet up to 40-fold differences were observed when compared to related reports on other mammalian species. The structural and adaptive bases of the variation in substrate and cofactor affinities need to be accounted for.
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Affiliation(s)
- Volkan Karacaoğlan
- Department of Biochemistry, School of Pharmacy, Hacettepe University, 06100 Ankara, Turkey
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Abstract
Multiple clinical and physiopathological studies as well as genetic analysis, suggest that diabetic retinopathy (DR) is a consequent of interactions between environmental factors, especially hyperglycaemia, and several genetic factors. The genes of aldose reductase (AR), inducible nitric oxide synthase (NOS2A), endothelial nitric oxide synthase (NOS3), vascular endothelial growth factor (VEGF), pigmented epithelium-derived factor (PEDF), protein kinase C-beta (PKC-beta) and receptor for advanced glycation end products (RAGE) implicated in the pathogenesis of DR. The only genetic marker associated with risk of DR in several studies is a microsatellite (A-C)n at 5'end of AR. The synergistic combination of conventional approaches (e.g. candidate gene association studies) with new emerging technologies (e.g. biochips) will be a key factor in the elucidation of the genetic aspects of DR.
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Affiliation(s)
- M J Taverna
- Laboratoire de Diabétologie, INSERM U.341, Hôpital Hôtel-Dieu, 75004 Paris.
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