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Liu Y, Lu CY, Zheng Y, Zhang YM, Qian LL, Li KL, Tse G, Wang RX, Liu T. Role of angiotensin receptor-neprilysin inhibitor in diabetic complications. World J Diabetes 2024; 15:867-875. [PMID: 38766431 PMCID: PMC11099356 DOI: 10.4239/wjd.v15.i5.867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 12/31/2023] [Accepted: 03/25/2024] [Indexed: 05/10/2024] Open
Abstract
Diabetes mellitus is a prevalent disorder with multi-system manifestations, causing a significant burden in terms of disability and deaths globally. Angio-tensin receptor-neprilysin inhibitor (ARNI) belongs to a class of medications for treating heart failure, with the benefits of reducing hospitalization rates and mortality. This review mainly focuses on the clinical and basic investigations related to ARNI and diabetic complications, discussing possible physiological and molecular mechanisms, with insights for future applications.
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Affiliation(s)
- Ying Liu
- Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Cun-Yu Lu
- Department of Cardiology, Xuzhou No. 1 Peoples Hospital, Xuzhou 221005, Jiangsu Province, China
| | - Yi Zheng
- Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Yu-Min Zhang
- Department of Cardiology, Wuxi 9th People’s Hospital Affiliated to Soochow University, Wuxi 214062, Jiangsu Province, China
| | - Ling-Ling Qian
- Department of Cardiology, Wuxi People’s Hospital Affiliated to Nanjing Medical University, Wuxi 214023, Jiangsu Province, China
| | - Ku-Lin Li
- Department of Cardiology, Wuxi People’s Hospital Affiliated to Nanjing Medical University, Wuxi 214023, Jiangsu Province, China
| | - Gary Tse
- Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China
- School of Nursing and Health Studies, Metropolitan University, Hong Kong 999077, China
- Kent and Medway Medical School, Kent CT2 7NT, Canterbury, United Kingdom
| | - Ru-Xing Wang
- Department of Cardiology, Wuxi People’s Hospital Affiliated to Nanjing Medical University, Wuxi 214023, Jiangsu Province, China
| | - Tong Liu
- Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China
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Faustino-Barros JF, Saranzo Sant'Ana AM, Dias LC, de Andrade Batista Murashima A, Costa Mendes da Silva LE, Fantucci MZ, Garcia DM, Rocha EM. Distinct Inflammatory and Oxidative Effects of Diabetes Mellitus and Hypothyroidism in the Lacrimal Functional Unit. Int J Mol Sci 2023; 24:ijms24086974. [PMID: 37108138 PMCID: PMC10138510 DOI: 10.3390/ijms24086974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/28/2023] [Accepted: 03/04/2023] [Indexed: 04/29/2023] Open
Abstract
Diabetes mellitus (DM) and hypothyroidism (HT) are prevalent diseases associated with dry eye (DE). Their impact on the lacrimal functional unit (LFU) is poorly known. This work evaluates the changes in the LFU in DM and HT. Adult male Wistar rats had the disease induced as follows: (a) DM: streptozotocin and (b) HT: methimazole. The tear film (TF) and blood osmolarity were measured. Cytokine mRNA was compared in the lacrimal gland (LG), trigeminal ganglion (TG), and cornea (CO). Oxidative enzymes were evaluated in the LG. The DM group showed lower tear secretion (p = 0.02) and higher blood osmolarity (p < 0.001). The DM group presented lower mRNA expression of TRPV1 in the cornea (p = 0.03), higher Il1b mRNA expression (p = 0.03), and higher catalase activity in the LG (p < 0.001). The DM group presented higher Il6 mRNA expression in the TG (p = 0.02). The HT group showed higher TF osmolarity (p < 0.001), lower expression of Mmp9 mRNA in the CO (p < 0.001), higher catalase activity in the LG (p = 0.002), and higher expression of Il1b mRNA in the TG (p = 0.004). The findings revealed that DM and HT induce distinct compromises to the LG and the entire LFU.
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Affiliation(s)
- Jacqueline Ferreira Faustino-Barros
- Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Ribeirão Preto Medical School, University of São Paulo, Ribeirao Preto 14049-900, Brazil
| | - Ariane Mirela Saranzo Sant'Ana
- Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Ribeirão Preto Medical School, University of São Paulo, Ribeirao Preto 14049-900, Brazil
| | - Lara Cristina Dias
- Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Ribeirão Preto Medical School, University of São Paulo, Ribeirao Preto 14049-900, Brazil
| | - Adriana de Andrade Batista Murashima
- Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Ribeirão Preto Medical School, University of São Paulo, Ribeirao Preto 14049-900, Brazil
| | - Lilian Eslaine Costa Mendes da Silva
- Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Ribeirão Preto Medical School, University of São Paulo, Ribeirao Preto 14049-900, Brazil
| | - Marina Zílio Fantucci
- Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Ribeirão Preto Medical School, University of São Paulo, Ribeirao Preto 14049-900, Brazil
| | - Denny Marcos Garcia
- Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Ribeirão Preto Medical School, University of São Paulo, Ribeirao Preto 14049-900, Brazil
| | - Eduardo Melani Rocha
- Department of Ophthalmology, Otorhinolaryngology and Head and Neck Surgery, Ribeirão Preto Medical School, University of São Paulo, Ribeirao Preto 14049-900, Brazil
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Bussan KA, Stuard WL, Mussi N, Lee W, Whitson JT, Issioui Y, Rowe AA, Wert KJ, Robertson DM. Differential effects of obstructive sleep apnea on the corneal subbasal nerve plexus and retinal nerve fiber layer. PLoS One 2022; 17:e0266483. [PMID: 35771778 PMCID: PMC9246161 DOI: 10.1371/journal.pone.0266483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 03/22/2022] [Indexed: 11/18/2022] Open
Abstract
Purpose Obstructive sleep apnea (OSA) is an established independent risk factor for peripheral neuropathy. Macro and microvascular changes have been documented in OSA, including high levels of potent vasoconstrictors. In diabetes, vasoconstriction has been identified as an underlying risk factor for corneal neuropathy. This study sought to establish a potential relationship between OSA and corneal nerve morphology and sensitivity, and to determine whether changes in corneal nerves may be reflective of OSA severity. Design Single center cross-sectional study. Methods Sixty-seven patients were stratified into two groups: those with OSA and healthy controls. Groups were matched for age, sex, race, smoking, and dry eye status. Outcome measures included serologies, a dilated fundus exam, dry eye testing, anthropometric parameters, corneal sensitivity, subbasal nerve plexus morphology, retinal nerve fiber layer (RNFL) thickness, and the use of questionnaires to assess symptoms of dry eye disease, risk of OSA, and continuous positive airway pressure (CPAP) compliance. Results No significant differences were observed in corneal nerve morphology, sensitivity, or the number of dendritic cells. In the OSA test group, RNFL thinning was noted in the superior and inferior regions of the optic disc and peripapillary region. A greater proportion of participants in the OSA group required a subsequent evaluation for glaucoma than in the control. In those with OSA, an increase in the apnea hypopnea index was associated with an increase in optic nerve cupping. Conclusions OSA does not exert a robust effect on corneal nerves. OSA is however, associated with thinning of the RNFL. Participants with glaucomatous optic nerve changes and risk factors for OSA should be examined as uncontrolled OSA may exacerbate glaucoma progression.
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Affiliation(s)
- Katherine A. Bussan
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Whitney L. Stuard
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Natalia Mussi
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Won Lee
- Department of Internal Medicine, Clinical Center for Sleep and Breathing Disorders, The University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Jess T. Whitson
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Yacine Issioui
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Ashley A. Rowe
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Katherine J. Wert
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Danielle M. Robertson
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, United States of America
- * E-mail:
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Bu Y, Shih KC, Tong L. The ocular surface and diabetes, the other 21st Century epidemic. Exp Eye Res 2022; 220:109099. [DOI: 10.1016/j.exer.2022.109099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 11/25/2022]
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Jolivalt CG, Han MM, Nguyen A, Desmond F, Alves Jesus CH, Vasconselos DC, Pedneault A, Sandlin N, Dunne-Cerami S, Frizzi KE, Calcutt NA. Using Corneal Confocal Microscopy to Identify Therapeutic Agents for Diabetic Neuropathy. J Clin Med 2022; 11:jcm11092307. [PMID: 35566433 PMCID: PMC9104226 DOI: 10.3390/jcm11092307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/19/2022] [Accepted: 04/19/2022] [Indexed: 02/04/2023] Open
Abstract
Corneal confocal microscopy (CCM) is emerging as a tool for identifying small fiber neuropathy in both peripheral neuropathies and neurodegenerative disease of the central nervous system (CNS). The value of corneal nerves as biomarkers for efficacy of clinical interventions against small fiber neuropathy and neurodegenerative disease is less clear but may be supported by preclinical studies of investigational agents. We, therefore, used diverse investigational agents to assess concordance of efficacy against corneal nerve loss and peripheral neuropathy in a mouse model of diabetes. Ocular delivery of the peptides ciliary neurotrophic factor (CNTF) or the glucagon-like peptide (GLP) analog exendin-4, both of which prevent diabetic neuropathy when given systemically, restored corneal nerve density within 2 weeks. Similarly, ocular delivery of the muscarinic receptor antagonist cyclopentolate protected corneal nerve density while concurrently reversing indices of systemic peripheral neuropathy. Conversely, systemic delivery of the muscarinic antagonist glycopyrrolate, but not gallamine, prevented multiple indices of systemic peripheral neuropathy and concurrently protected against corneal nerve loss. These data highlight the potential for use of corneal nerve quantification by confocal microscopy as a bridging assay between in vitro and whole animal assays in drug development programs for neuroprotectants and support its use as a biomarker of efficacy against peripheral neuropathy.
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Yorek M. Treatment for Diabetic Peripheral Neuropathy: What have we Learned from Animal Models? Curr Diabetes Rev 2022; 18:e040521193121. [PMID: 33949936 PMCID: PMC8965779 DOI: 10.2174/1573399817666210504101609] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/07/2021] [Accepted: 02/13/2021] [Indexed: 11/22/2022]
Abstract
INTRODUCTION Animal models have been widely used to investigate the etiology and potential treatments for diabetic peripheral neuropathy. What we have learned from these studies and the extent to which this information has been adapted for the human condition will be the subject of this review article. METHODS A comprehensive search of the PubMed database was performed, and relevant articles on the topic were included in this review. RESULTS Extensive study of diabetic animal models has shown that the etiology of diabetic peripheral neuropathy is complex, with multiple mechanisms affecting neurons, Schwann cells, and the microvasculature, which contribute to the phenotypic nature of this most common complication of diabetes. Moreover, animal studies have demonstrated that the mechanisms related to peripheral neuropathy occurring in type 1 and type 2 diabetes are likely different, with hyperglycemia being the primary factor for neuropathology in type 1 diabetes, which contributes to a lesser extent in type 2 diabetes, whereas insulin resistance, hyperlipidemia, and other factors may have a greater role. Two of the earliest mechanisms described from animal studies as a cause for diabetic peripheral neuropathy were the activation of the aldose reductase pathway and increased non-enzymatic glycation. However, continuing research has identified numerous other potential factors that may contribute to diabetic peripheral neuropathy, including oxidative and inflammatory stress, dysregulation of protein kinase C and hexosamine pathways, and decreased neurotrophic support. In addition, recent studies have demonstrated that peripheral neuropathy-like symptoms are present in animal models, representing pre-diabetes in the absence of hyperglycemia. CONCLUSION This complexity complicates the successful treatment of diabetic peripheral neuropathy, and results in the poor outcome of translating successful treatments from animal studies to human clinical trials.
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Affiliation(s)
- Mark Yorek
- Department of Internal Medicine, University of Iowa, Iowa City, IA, 52242 USA
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA, 52246 USA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, 52242 USA
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Petropoulos IN, Ponirakis G, Ferdousi M, Azmi S, Kalteniece A, Khan A, Gad H, Bashir B, Marshall A, Boulton AJM, Soran H, Malik RA. Corneal Confocal Microscopy: A Biomarker for Diabetic Peripheral Neuropathy. Clin Ther 2021; 43:1457-1475. [PMID: 33965237 DOI: 10.1016/j.clinthera.2021.04.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/05/2021] [Accepted: 04/08/2021] [Indexed: 02/08/2023]
Abstract
PURPOSE Diagnosing early diabetic peripheral neuropathy remains a challenge due to deficiencies in currently advocated end points. The cornea is densely innervated with small sensory fibers, which are structurally and functionally comparable to intraepidermal nerve fibers. Corneal confocal microscopy is a method for rapid, noninvasive scanning of the living cornea with high resolution and magnification. METHODS This narrative review presents the framework for the development of biomarkers and the literature on the use and adoption of corneal confocal microscopy as an objective, diagnostic biomarker in experimental and clinical studies of diabetic peripheral neuropathy. A search was performed on PubMed and Google Scholar based on the terms "corneal confocal microscopy," "diabetic neuropathy," "corneal sensitivity," and "clinical trials." FINDINGS A substantial body of evidence underpins the thesis that corneal nerve loss predicts incident neuropathy and progresses with the severity of diabetic peripheral neuropathy. Corneal confocal microscopy also identifies early corneal nerve regeneration, strongly arguing for its inclusion as a surrogate end point in clinical trials of disease-modifying therapies. IMPLICATIONS There are sufficient diagnostic and prospective validation studies to fulfill the US Food and Drug Administration criteria for a biomarker to support the inclusion of corneal confocal microscopy as a primary end point in clinical trials of disease-modifying therapies in diabetic neuropathy.
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Affiliation(s)
| | | | - Maryam Ferdousi
- Faculty of Biology, Medicine and Health, University of Manchester, Cardiovascular Trials Unit, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Shazli Azmi
- Faculty of Biology, Medicine and Health, University of Manchester, Cardiovascular Trials Unit, Manchester University NHS Foundation Trust, Manchester, United Kingdom; Centre for Diabetes, Endocrinology and Metabolism, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Alise Kalteniece
- Faculty of Biology, Medicine and Health, University of Manchester, Cardiovascular Trials Unit, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Adnan Khan
- Research Division, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Hoda Gad
- Research Division, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Bilal Bashir
- Centre for Diabetes, Endocrinology and Metabolism, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Andrew Marshall
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom; Clinical Neurophysiology, The Walton Centre, Liverpool, United Kingdom; Division of Neuroscience and Experimental Psychology, Faculty of Medical and Human Sciences, University of Manchester, Manchester, United Kingdom
| | - Andrew J M Boulton
- Faculty of Biology, Medicine and Health, University of Manchester, Cardiovascular Trials Unit, Manchester University NHS Foundation Trust, Manchester, United Kingdom; Centre for Diabetes, Endocrinology and Metabolism, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Handrean Soran
- Faculty of Biology, Medicine and Health, University of Manchester, Cardiovascular Trials Unit, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Rayaz A Malik
- Research Division, Weill Cornell Medicine-Qatar, Doha, Qatar; Faculty of Biology, Medicine and Health, University of Manchester, Cardiovascular Trials Unit, Manchester University NHS Foundation Trust, Manchester, United Kingdom.
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Mansoor H, Tan HC, Lin MTY, Mehta JS, Liu YC. Diabetic Corneal Neuropathy. J Clin Med 2020; 9:jcm9123956. [PMID: 33291308 PMCID: PMC7762152 DOI: 10.3390/jcm9123956] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 11/26/2020] [Accepted: 12/03/2020] [Indexed: 12/14/2022] Open
Abstract
Diabetic keratopathy (DK) is a common, but underdiagnosed, ocular complication of diabetes mellitus (DM) that has a significant economic burden. It is characterised by progressive damage of corneal nerves, due to DM-induced chronic hyperglycaemia and its associated metabolic changes. With advances in corneal nerve imaging and quantitative analytic tools, studies have shown that the severity of diabetic corneal neuropathy correlates with the status of diabetic peripheral neuropathy. The corneal nerve plexus is, therefore, considered as an important surrogate marker of diabetic peripheral neuropathy and helps in the evaluation of interventional efficacy in the management of DM. The clinical manifestations of DK depend on the disease severity and vary from decreased corneal sensitivity to sight-threatening corneal infections and neurotrophic ulcers. The severity of diabetic corneal neuropathy and resultant DK determines its management plan, and a step-wise approach is generally suggested. Future work would focus on the exploration of biomarkers for diabetic corneal neuropathy, the development of new treatment for corneal nerve protection, and the improvement in the clinical assessment, as well as current imaging technique and analysis, to help clinicians detect diabetic corneal neuropathy earlier and monitor the sub-clinical progression more reliably.
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Affiliation(s)
- Hassan Mansoor
- Al Shifa Trust Eye Hospital, Rawalpindi 44000, Pakistan;
| | - Hong Chang Tan
- Department of Endocrinology, Singapore General Hospital, Singapore 169608, Singapore;
| | - Molly Tzu-Yu Lin
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore; (M.T.-Y.L.); (J.S.M.)
| | - Jodhbir S. Mehta
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore; (M.T.-Y.L.); (J.S.M.)
- Cornea and External Eye Diseases, Singapore National Eye Centre, Singapore 168751, Singapore
- Eye-Academic Clinical Program, Duke-National University Singapore Graduate Medical School, Singapore 169857, Singapore
| | - Yu-Chi Liu
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore; (M.T.-Y.L.); (J.S.M.)
- Cornea and External Eye Diseases, Singapore National Eye Centre, Singapore 168751, Singapore
- Eye-Academic Clinical Program, Duke-National University Singapore Graduate Medical School, Singapore 169857, Singapore
- Correspondence: ; Tel.: +65-65-767-246; Fax: +65-62-277-290
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Li W, Wang X, Cheng J, Li J, Wang Q, Zhou Q, Li H, Xue J, Zhang Y, Yang L, Xie L. Leucine-rich α-2-glycoprotein-1 promotes diabetic corneal epithelial wound healing and nerve regeneration via regulation of matrix metalloproteinases. Exp Eye Res 2020; 196:108060. [DOI: 10.1016/j.exer.2020.108060] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 04/23/2020] [Accepted: 04/28/2020] [Indexed: 12/17/2022]
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Jiao X, Lu D, Pei X, Qi D, Huang S, Song Z, Gu J, Li Z. Type 1 diabetes mellitus impairs diurnal oscillations in murine extraorbital lacrimal glands. Ocul Surf 2020; 18:438-452. [PMID: 32360784 DOI: 10.1016/j.jtos.2020.04.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 04/20/2020] [Accepted: 04/23/2020] [Indexed: 01/09/2023]
Abstract
PURPOSE People with diabetes are at high risk of lacrimal gland dysfunction, but the underlying mechanism is not well understood. In this study, we determined how type 1 diabetes mellitus (T1DM) influences circadian homeostasis of the murine extraorbital lacrimal glands (ELGs). METHODS A T1DM animal model was established by systemic streptozotocin injection in C57BL/6J mice. After 5 weeks, ELGs were collected at 3-h intervals over a 24-h circadian cycle. Total extracted RNA was subjected to high-throughput RNA sequencing, and rhythmic transcriptional data were evaluated using the Jonckheere-Terpstra-Kendall algorithm, Kyoto Encyclopedia of Genes and Genomes pathway analysis, Phase Set Enrichment Analysis, and time series cluster analysis to determine the phase, rhythmicity, and unique signature of the transcripts over temporally coordinated expression. Additionally, mass, cell size, histology, and tear secretion of the ELGs were evaluated. RESULTS T1DM globally altered the composition of the ELG transcriptome. Specifically, T1DM significantly reprogrammed the circadian transcriptomic profiles of normal ELGs and reorganized core clock machinery. Unique temporal and clustering enrichment pathways were also rewired by T1DM. Finally, normal daily rhythms of mass, cell size, and tear secretion of mouse ELGs were significantly impaired by streptozotocin-induced diabetes. CONCLUSIONS T1DM significantly reprograms the diurnal oscillations of the lacrimal glands and impairs their structure and tear secretion. This information may reveal potential targets for improving lacrimal gland dysfunction in patients with diabetes.
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Affiliation(s)
- Xinwei Jiao
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou, China
| | - Dingli Lu
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou, China
| | - Xiaoting Pei
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou, China
| | - Di Qi
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou, China
| | - Shenzhen Huang
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou, China
| | - Zongming Song
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou, China
| | - Jianqin Gu
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou, China
| | - Zhijie Li
- Henan Eye Institute, Henan Eye Hospital and Henan Key Laboratory of Ophthalmology and Visual Science, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, People's Hospital of Henan University, Zhengzhou, China.
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11
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Ozaki K, Matsuura T. Superimposition of hypertension on diabetic peripheral neuropathy affects small unmyelinated sensory nerves in the skin and myelinated tibial and sural nerves in rats with alloxan-induced type 1 diabetes. J Toxicol Pathol 2020; 33:161-169. [PMID: 32764841 PMCID: PMC7396736 DOI: 10.1293/tox.2020-0003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 03/19/2020] [Indexed: 11/19/2022] Open
Abstract
Diabetic peripheral neuropathy (DPN) is a major complication of diabetes mellitus, and hypertension is considered to be a risk factor for DPN in patients with type 1 diabetes (T1DM). However, the morphological effects of hypertension on DPN are unclear. In this study, we investigated the effect of hypertension on DPN by investigating the changes in unmyelinated and myelinated nerve fibers in hypertensive rats with alloxan (AL)-induced T1DM. Thirteen-week-old WBN/Kob rats with AL-induced diabetes were allocated to receive tap water only (AL group), tap water containing 0.5% saline (0.5AN group), or tap water containing 0.75% saline (0.75AN group) for 15 weeks. Hyperglycemia was maintained for 15 weeks, and the animals were euthanized at 28 weeks. By 23 weeks of age, the systolic blood pressure was significantly higher in the 0.75AN and 0.5AN groups than in the AL group and was unchanged in all groups at 28 weeks. The number of intraepidermal sensory unmyelinated nerve fibers was significantly smaller in the 0.75AN and 0.5AN groups than in the AL group. The axonal size in the myelinated tibial and sural nerve fibers was significantly smaller in the 0.75AN group than in the AL group. Furthermore, luminal narrowing and endothelial hypertrophy were observed in the endoneurial tibial nerve vessels in the 0.75AN group. These findings suggest that superimposing hypertension on hyperglycemia may accelerate a reduction in the number of small unmyelinated sensory nerve fibers in the skin and induce mild axonal atrophy in myelinated tibial and sural nerve fibers in rats with AL-induced T1DM.
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Affiliation(s)
- Kiyokazu Ozaki
- Laboratory of Pathology, Faculty of Pharmaceutical Science, Setsunan University, 45-1 Nagaotohge-cho, Hirakata, Osaka 573-0101, Japan
| | - Tetsuro Matsuura
- Laboratory of Pathology, Faculty of Pharmaceutical Science, Setsunan University, 45-1 Nagaotohge-cho, Hirakata, Osaka 573-0101, Japan
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12
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Coppey L, Davidson E, Shevalye H, Obrosov A, Torres M, Yorek MA. Progressive Loss of Corneal Nerve Fibers and Sensitivity in Rats Modeling Obesity and Type 2 Diabetes Is Reversible with Omega-3 Fatty Acid Intervention: Supporting Cornea Analyses as a Marker for Peripheral Neuropathy and Treatment. Diabetes Metab Syndr Obes 2020; 13:1367-1384. [PMID: 32425569 PMCID: PMC7189026 DOI: 10.2147/dmso.s247571] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/31/2020] [Indexed: 12/21/2022] Open
Abstract
PURPOSE To determine whether cornea nerve fiber density and/or corneal function are valid markers for early detection and treatment of peripheral neuropathy in rats modeling prediabetes and type 2 diabetes. METHODS High-fat feeding combined without or with low-dose streptozotocin was used to create rat models for prediabetes and type 2 diabetes that were longitudinally studied for loss of structure and function of sensory nerves in the cornea and skin as well as nerve conduction velocity and vascular reactivity of epineurial arterioles. There were three time points examined in each of the three conditions with 12 rats per group. The latest time point (24 weeks of high-fat diet with or without 16 weeks of hyperglycemia) was used to examine reversibility of neuro and vascular pathology following 16 weeks of treatment with menhaden oil, a natural source of long-chain omega-3 polyunsaturated fatty acids. The number of rats in the intervention study ranged from 6 to 17. RESULTS Our longitudinal study demonstrated that vascular and neural dysfunction associated with obesity or type 2 diabetes occur early and are progressive. Decrease in cornea nerve fiber length and function were valid markers of disease in both the pre-diabetic and diabetic rat models and were more sensitive than decrease in intraepidermal nerve fiber density of the skin and thermal nociception of the hindpaw. Late intervention with menhaden oil significantly reversed both vascular and peripheral nerve damage induced by chronic obesity or type 2 diabetes. CONCLUSION These studies provide support for examination of corneal structure and function as an early marker of peripheral neuropathy in prediabetes and type 2 diabetes. Furthermore, we demonstrate that omega-3 polyunsaturated fatty acids derived from fish oil are an effective treatment for peripheral neuropathy that occurs with chronic obesity or type 2 diabetes.
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Affiliation(s)
- Lawrence Coppey
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | - Eric Davidson
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | - Hanna Shevalye
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | - Alexander Obrosov
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | - Michael Torres
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
| | - Mark A Yorek
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
- Department of Veterans Affairs, Iowa City Health Care System, Iowa City, IA, USA
- Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA, USA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, USA
- Correspondence: Mark A Yorek Department of Veterans Affairs, Iowa City Health Care System, Iowa City, IA52246Tel +1-319-338-0581 ext. 7696Fax +1-319-339-7162 Email
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Ozaki K, Terayama Y, Matsuura T. Hyperglycemia Suppresses Age-Related Increases in Corneal Peripheral Sensory Nerves in Wistar Bon Kobori (WBN/Kob) Rats. Invest Ophthalmol Vis Sci 2019; 60:4151-4158. [PMID: 31598626 DOI: 10.1167/iovs.19-28060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Nerve fiber density in the cornea is an alternative marker for diabetic peripheral neuropathy combined with intraepidermal nerve fiber density (IENFD). Recent studies investigated corneal nerves using rodent models of diabetes. Male Wistar Bon Kobori (WBN/Kob) rats spontaneously develop long-lasting diabetes and human-like diabetic peripheral neuropathy with vascular lesions. This study investigated corneal nerve fiber density and IENFD in diabetic male WBN/Kob rats as morphological markers of diabetic peripheral neuropathy. Methods Male WBN/Kob rats exhibit abnormal glucose tolerance and diabetes at approximately 30 weeks of age, which progresses until approximately 90 weeks of age. Male WBN/Kob rats aged 36 and 90 weeks were therefore used for histological investigations and compared with age-matched nondiabetic female rats. Results Terminal epithelial nerve density and subbasal nerve plexus density in the central cornea were significantly greater in nondiabetic female rats aged 90 weeks when compared with nondiabetic female rats aged 36 weeks. However, terminal epithelial nerve density and subbasal nerve plexus density did not increase with age in diabetic male WBN/Kob rats, instead lowering by up to 40%, relative to measurements in nondiabetic female rats aged 90 weeks. However, this difference was not statistically significant. IENFD was significantly lower in diabetic male rats aged 90 weeks than in male rats aged 36 weeks, but did not differ between diabetic male rats and nondiabetic female rats aged 90 weeks. Conclusions In WBN/Kob rats, hyperglycemia suppresses an age-related increase in peripheral sensory corneal nerve density; therefore, corneal sensory nerves may be important morphological markers of diabetic peripheral sensory neuropathy.
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Affiliation(s)
- Kiyokazu Ozaki
- Laboratory of Pathology, Faculty of Pharmaceutical Science, Setsunan University, Hirakata, Osaka, Japan
| | - Yui Terayama
- Laboratory of Pathology, Faculty of Pharmaceutical Science, Setsunan University, Hirakata, Osaka, Japan
| | - Tetsuro Matsuura
- Laboratory of Pathology, Faculty of Pharmaceutical Science, Setsunan University, Hirakata, Osaka, Japan
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14
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Zhu L, Titone R, Robertson DM. The impact of hyperglycemia on the corneal epithelium: Molecular mechanisms and insight. Ocul Surf 2019; 17:644-654. [PMID: 31238114 DOI: 10.1016/j.jtos.2019.06.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 06/11/2019] [Accepted: 06/21/2019] [Indexed: 12/15/2022]
Abstract
Type 2 Diabetes Mellitus (T2DM) is reaching epidemic levels worldwide and with it, there is a significant increase in complications associated with the disease. T2DM affects virtually all organ systems including the eye. While frequently overlooked, diabetic keratopathy is the most common ocular complication of diabetes and can manifest in mild to severe forms, the latter of which poses a major threat to vision. As the initial barrier between the environment and the eye, the corneal epithelium functions in innate immune defense. Compromise of this barrier may predispose the cornea to infection and can hinder the refractive capabilities of the eye. The clinical burden in patients with diabetic keratopathy lies primarily in the inability of the corneal epithelium to repair damage and maintain its tight barrier function. Current therapies for diabetic keratopathy are supportive, centering on the prevention of infection and promotion of an optimal healing environment. With no clear disease-modifying agent identified as of yet, a thorough understanding of the pathophysiology that underlies the development of diabetic keratopathy at the cellular level is critical to identify and develop potential therapeutic agents capable of promoting corneal re-epithelialization to accelerate the wound healing process. The focus of this review is to examine what is known regarding the cellular and molecular mechanisms needed to maintain epithelial homeostasis and how it goes awry in diabetes.
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Affiliation(s)
- Luke Zhu
- Department of Ophthalmology, University of Texas Southwestern Medical Center, United States
| | - Rossella Titone
- Department of Ophthalmology, University of Texas Southwestern Medical Center, United States
| | - Danielle M Robertson
- Department of Ophthalmology, University of Texas Southwestern Medical Center, United States.
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15
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Ozaki K, Terayama Y, Matsuura T. Extended Duration of Hyperglycemia Result in Human-Like Corneal Nerve Lesions in Mice With Alloxan- and Streptozotocin-Induced Type 1 Diabetes. Invest Ophthalmol Vis Sci 2019; 59:5868-5875. [PMID: 30550618 DOI: 10.1167/iovs.18-25693] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Previous experimental studies assessing corneal nerves as a measure of the severity of diabetic peripheral neuropathy have yielded discordant results; this may have been due to the effect of the short duration of the induced diabetes. We investigated whether increases in the duration of hyperglycemia result in the development of corneal lesions in a mouse model of alloxan (AL)- or streptozotocin (STZ)-induced type 1 diabetes. We further determined whether corneal nerve fiber density, intraepidermal nerve fiber density (IENFD), and sural nerve morphology can be used as morphologic markers of diabetic peripheral neuropathy in rodent models. Methods A total of 30 female ICR mice were divided into three groups: those with STZ-induced (STZ group) and AL-induced (AL group) diabetes, and a control group. Hyperglycemia was maintained in diabetic mice for 35 weeks. Animals were euthanized at 41 weeks of age. Results Subbasal nerve plexus density (SBNPD) and terminal epithelial nerve density (TEND) in the cornea, as well as IENFD, were significantly lower, and mean sural nerve axon sizes were smaller in mice in the STZ and AL groups than in the control group. There were significant correlations between IENFD and SBNPD, and between IENFD and TEND. Conclusions These results indicate that the TEND and SBNTD of the cornea may be useful morphologic markers for diabetic peripheral neuropathy.
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Affiliation(s)
- Kiyokazu Ozaki
- Laboratory of Pathology, Faculty of Pharmaceutical Science, Setsunan University, Osaka, Japan
| | - Yui Terayama
- Laboratory of Pathology, Faculty of Pharmaceutical Science, Setsunan University, Osaka, Japan
| | - Tetsuro Matsuura
- Laboratory of Pathology, Faculty of Pharmaceutical Science, Setsunan University, Osaka, Japan
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Lee PSY, Gao N, Dike M, Shkilnyy O, Me R, Zhang Y, Yu FSX. Opposing Effects of Neuropilin-1 and -2 on Sensory Nerve Regeneration in Wounded Corneas: Role of Sema3C in Ameliorating Diabetic Neurotrophic Keratopathy. Diabetes 2019; 68:807-818. [PMID: 30679185 PMCID: PMC6425876 DOI: 10.2337/db18-1172] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/14/2019] [Indexed: 12/21/2022]
Abstract
The diabetic cornea exhibits pathological alterations, such as delayed epithelial wound healing and nerve regeneration. We investigated the role of semaphorin (SEMA) 3C in corneal wound healing and reinnervation in normal and diabetic B6 mice. Wounding induced the expression of SEMA3A, SEMA3C, and their receptor neuropilin-2 (NRP2), but not NRP1, in normal corneal epithelial cells; this upregulation was suppressed for SEMA3C and NRP2 in diabetic corneas. Injections of Sema3C-specific small interfering RNA and NRP2-neutralizing antibodies in wounded mice resulted in a decrease in the rate of wound healing and regenerating nerve fibers, whereas exogenous SEMA3C had opposing effects in diabetic corneas. NRP1 neutralization, on the other hand, decreased epithelial wound closure but increased sensory nerve regeneration in diabetic corneas, suggesting a detrimental role in nerve regeneration. Taken together, epithelium-expressed SEMA3C plays a role in corneal epithelial wound closure and sensory nerve regeneration. The hyperglycemia-suppressed SEMA3C/NRP2 signaling may contribute to the pathogenesis of diabetic neurotrophic keratopathy, and SEMA3C might be used as an adjunctive therapeutic for treating the disease.
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Affiliation(s)
- Patrick Shean-Young Lee
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
| | - Nan Gao
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
| | - Mamata Dike
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
| | - Olga Shkilnyy
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
| | - Rao Me
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
| | - Yangyang Zhang
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
- Qingdao Eye Hospital, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao, China
| | - Fu-Shin X Yu
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
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Bussan KA, Robertson DM. Contact lens wear and the diabetic corneal epithelium: A happy or disastrous marriage? J Diabetes Complications 2019; 33:75-83. [PMID: 30391097 PMCID: PMC7364814 DOI: 10.1016/j.jdiacomp.2018.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/10/2018] [Accepted: 09/23/2018] [Indexed: 12/11/2022]
Abstract
Diabetes mellitus is an epidemic in the US and abroad. With the advent of new contact lens technology, the use of contact lenses as glucose sensors in lieu of the traditional finger stick is quickly becoming realized. This has the potential to rapidly expand the contact lens market into this growing patient population. The independent cellular and physiological effects of contact lens wear and diabetes on the corneal epithelium have been described. However, little evidence exists to date to support whether there is increased risk associated with contact lens wear in diabetes. The focus of this review is to discuss what is known about the cellular effects of contact lenses on the corneal epithelium, the pathophysiological changes in the corneal epithelium that occur in diabetes, and whether an increased risk for corneal epithelial damage and/or infection may negatively impact safety in diabetic contact lens wearers. Available data indicates that there are inherent risks associated with contact lens wear in diabetics. Importantly, eye care practitioners fitting contact lenses in the diabetic patient need to carefully consider the duration of disease, the level of glycemic control, the presence of retinopathy, and the patient's overall health.
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Affiliation(s)
- Katherine A Bussan
- The Department of Ophthalmology, The University of Texas Southwestern Medical Center, United States of America
| | - Danielle M Robertson
- The Department of Ophthalmology, The University of Texas Southwestern Medical Center, United States of America.
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18
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ČESKÁ BURDOVÁ M, KULICH M, DOTŘELOVÁ D, MAHELKOVÁ G. Effect of Diabetes Mellitus Type 1 Diagnosis on the Corneal Cell Densities and Nerve Fibers. Physiol Res 2018; 67:963-974. [DOI: 10.33549/physiolres.933899] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Relation of diabetes mellitus (DM) to the various stages of corneal nerve fiber damage is well accepted. A possible association between changes in the cornea of diabetic patients and diabetic retinopathy (DR), DM duration, and age at the time of DM diagnosis were evaluated. The study included 60 patients with DM type 1 (DM1) and 20 healthy control subjects. The density of basal epithelial cells, keratocytes and endothelial cells, and the status of the subbasal nerve fibers were evaluated using in vivo corneal confocal microscopy. Basal epithelial cell density increased with age (p=0.026), while stromal and endothelial cell density decreased with age (p=0.003, p=0.0005, p<0.0001). After the DM1 diagnosis was established, this association with age weaken. We showed nerve fiber damage in DM1 patients (p˂0.0001). The damage correlated with the degree of DR. DM1 patients with higher age at DM1 diagnosis had a higher nerve fiber density (p=0.0021). These results indicated that age at DM1 diagnosis potentially has an important effect on final nerve fiber and corneal cell density.
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Affiliation(s)
| | | | | | - G. MAHELKOVÁ
- Department of Ophthalmology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
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19
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Insulin-like growth factor-1 activates AMPK to augment mitochondrial function and correct neuronal metabolism in sensory neurons in type 1 diabetes. Mol Metab 2018; 20:149-165. [PMID: 30545741 PMCID: PMC6358538 DOI: 10.1016/j.molmet.2018.11.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/20/2018] [Accepted: 11/23/2018] [Indexed: 12/13/2022] Open
Abstract
Objective Diabetic sensorimotor polyneuropathy (DSPN) affects approximately half of diabetic patients leading to significant morbidity. There is impaired neurotrophic growth factor signaling, AMP-activated protein kinase (AMPK) activity and mitochondrial function in dorsal root ganglia (DRG) of animal models of type 1 and type 2 diabetes. We hypothesized that sub-optimal insulin-like growth factor 1 (IGF-1) signaling in diabetes drives loss of AMPK activity and mitochondrial function, both contributing to development of DSPN. Methods Age-matched control Sprague-Dawley rats and streptozotocin (STZ)-induced type 1 diabetic rats with/without IGF-1 therapy were used for in vivo studies. For in vitro studies, DRG neurons from control and STZ-diabetic rats were cultured and treated with/without IGF-1 in the presence or absence of inhibitors or siRNAs. Results Dysregulation of mRNAs for IGF-1, AMPKα2, ATP5a1 (subunit of ATPase), and PGC-1β occurred in DRG of diabetic vs. control rats. IGF-1 up-regulated mRNA levels of these genes in cultured DRGs from control or diabetic rats. IGF-1 treatment of DRG cultures significantly (P < 0.05) increased phosphorylation of Akt, P70S6K, AMPK and acetyl-CoA carboxylase (ACC). Mitochondrial gene expression and oxygen consumption rate (spare respiratory capacity), ATP production, mtDNA/nDNA ratio and neurite outgrowth were augmented (P < 0.05). AMPK inhibitor, Compound C, or AMPKα1-specific siRNA suppressed IGF-1 elevation of mitochondrial function, mtDNA and neurite outgrowth. Diabetic rats treated with IGF-1 exhibited reversal of thermal hypoalgesia and, in a separate study, reversed the deficit in corneal nerve profiles. In diabetic rats, IGF-1 elevated the levels of AMPK and P70S6K phosphorylation, raised Complex IV-MTCO1 and Complex V-ATP5a protein expression, and restored the enzyme activities of Complex IV and I in the DRG. IGF-1 prevented TCA metabolite build-up in nerve. Conclusions In DRG neuron cultures IGF-1 signals via AMPK to elevate mitochondrial function and drive axonal outgrowth. We propose that this signaling axis mediates IGF-1-dependent protection from distal dying-back of fibers in diabetic neuropathy. IGF-1 activates AMPK to drive mitochondrial phenotype in sensory neurons. AMPK isoforms differentially regulate mitochondrial gene expression and respiratory activity. IGF-1 treatment of type 1 diabetic rodents protected from neuropathy. DRG of diabetic rats treated with IGF-1 exhibited raised activity and gene expression of AMPK and respiratory complexes.
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Davidson EP, Coppey LJ, Shevalye H, Obrosov A, Yorek MA. Vascular and Neural Complications in Type 2 Diabetic Rats: Improvement by Sacubitril/Valsartan Greater Than Valsartan Alone. Diabetes 2018; 67:1616-1626. [PMID: 29941448 DOI: 10.2337/db18-0062] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 03/15/2018] [Indexed: 11/13/2022]
Abstract
Previously, we had shown that a vasopeptidase inhibitor drug containing ACE and neprilysin inhibitors was an effective treatment for diabetic vascular and neural complications. However, side effects prevented further development. This led to the development of sacubitril/valsartan, a drug containing angiotensin II receptor blocker and neprilysin inhibitor that we hypothesized would be an effective treatment for diabetic peripheral neuropathy. Using early and late intervention protocols (4 and 12 weeks posthyperglycemia, respectively), type 2 diabetic rats were treated with valsartan or sacubitril/valsartan for 12 weeks followed by an extensive evaluation of vascular and neural end points. The results demonstrated efficacy of sacubitril/valsartan in improving vascular and neural function was superior to valsartan alone. In the early intervention protocol, sacubitril/valsartan treatment was found to slow progression of these deficits and, with late intervention treatment, was found to stimulate restoration of vascular reactivity, motor and sensory nerve conduction velocities, and sensitivity/regeneration of sensory nerves of the skin and cornea in a rat model of type 2 diabetes. These preclinical studies suggest that sacubitril/valsartan may be an effective treatment for diabetic peripheral neuropathy, but additional studies will be needed to investigate these effects further.
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Affiliation(s)
- Eric P Davidson
- Department of Internal Medicine, University of Iowa, Iowa City, IA
| | | | - Hanna Shevalye
- Department of Internal Medicine, University of Iowa, Iowa City, IA
| | | | - Mark A Yorek
- Department of Internal Medicine, University of Iowa, Iowa City, IA
- Department of Veterans Affairs, Iowa City VA Health Care System, Iowa City, IA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
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Kneer K, Green MB, Meyer J, Rich CB, Minns MS, Trinkaus-Randall V. High fat diet induces pre-type 2 diabetes with regional changes in corneal sensory nerves and altered P2X7 expression and localization. Exp Eye Res 2018; 175:44-55. [PMID: 29883639 DOI: 10.1016/j.exer.2018.06.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/23/2018] [Accepted: 06/03/2018] [Indexed: 12/31/2022]
Abstract
Type 2 diabetes is one of the leading pathologies that increases the risk of improper wound healing. Obesity has become a major risk factor for this disease that is now considered to be the 4th highest cause of preventable blindness according to the World Health Organization. The cornea is the most densely innervated structure in the human body and senses even the slightest injury. In diabetes, decreased corneal sensitivity secondary to diabetic peripheral neuropathy can lead to increased corneal abrasion, ulceration, and even blindness. In this study, a diet induced obesity (DIO) mouse model of pre-Type 2 diabetes was used to characterize changes in sensory nerves and P2X7, a purinoreceptor, a pain receptor, and an ion channel that is expressed in a number of tissues. Since our previous studies demonstrated that P2X7 mRNA was significantly elevated in diabetic human corneas, we examined P2X7 expression and localization in the DIO murine model at various times after being fed a high fat diet. Fifteen weeks after onset of diet, we found that there was a significant decrease in the density of sub-basal nerves in the DIO mice that was associated with an increase in tortuosity and a decrease in diameter. In addition, P2X7 mRNA expression was significantly greater in the corneal epithelium of DIO mice, and the increase in transcript was enhanced in the central migrating and peripheral regions after injury. Interestingly, confocal microscopy and thresholding analysis revealed that there was a significant increase in P2X7 distal to the injury, which contrasted with a decrease in P2X7-expressing stromal sensory nerves. Therefore, we hypothesize that the P2X7 receptor acts to sense changes at the leading edge following an epithelial abrasion, and this fine-tuned regulation is lost during the onset of diabetes. Further understanding of the corneal changes that occur in diabetes can help us better monitor progression of diabetic complications, as well as develop new therapeutics for the treatment of diabetic corneal dysfunction.
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Affiliation(s)
- Krisandra Kneer
- Boston University School of Medicine, 80 E. Concord St. Boston, MA, 02118, USA.
| | - Michael B Green
- Boston University School of Medicine, 80 E. Concord St. Boston, MA, 02118, USA.
| | - Jenna Meyer
- Boston University School of Medicine, 80 E. Concord St. Boston, MA, 02118, USA.
| | - Celeste B Rich
- Boston University School of Medicine, 80 E. Concord St. Boston, MA, 02118, USA.
| | - Martin S Minns
- Boston University School of Medicine, 80 E. Concord St. Boston, MA, 02118, USA.
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Abstract
Supplemental Digital Content is Available in the Text. Purpose: To evaluate the efficacy of sodium hyaluronate (HA) eye drops for the treatment of diabetic ocular surface diseases in mice. Methods: Male 6- to 8-week-old C57BL/6 mice underwent induction of type 1 diabetes with intraperitoneal injections of streptozotocin, with normal mice as the control. Topical 0.3% HA, 0.1% HA, 0.4% polyethylene glycol eye drops, and normal saline were administered to diabetic mice with an intact or debrided corneal epithelium. Normal saline was applied in the controls. Corneal epithelial wound healing rate, corneal sensation, nerve fiber density, conjunctival goblet cell number, and MUC-5AC content were measured and compared. Results: Compared with the controls, topical 0.3% HA use in diabetic mice showed significant improvements in the corneal epithelial wound healing rate (48 hours: 91.5% ± 4.8% vs. 79.8% ± 6.1%; P < 0.05), corneal sensitivity (4.1 ± 0.3 cm vs. 3.5 ± 0.3 cm; P < 0.05), nerve fiber density (12.9% ± 2.3% vs. 6.6% ± 2.4%; P < 0.05), conjunctival goblet cell number (31.0 ± 8.4/100 μm vs. 19.6 ± 7.1/100 μm; P < 0.05), and MUC-5AC content (12.5 ± 1.4 ng/mg vs. 7.8 ± 1.5 ng/mg protein; P < 0.05). The beneficial effects of 0.3% HA were better than those of 0.1% HA and 0.4% polyethylene glycol. Conclusions: Topical 0.3% HA treatment promoted corneal epithelial regeneration, improved corneal sensation, and increased density of corneal nerve fibers and conjunctival goblet cells in mice with diabetic ocular surface diseases.
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Obrosov A, Coppey LJ, Shevalye H, Yorek MA. Effect of Fish Oil vs. Resolvin D1, E1, Methyl Esters of Resolvins D1 or D2 on Diabetic Peripheral Neuropathy. ACTA ACUST UNITED AC 2017; 8. [PMID: 29423332 PMCID: PMC5800519 DOI: 10.4172/2155-9562.1000453] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Objective Fish oil is enriched in omega-3 polyunsaturated fatty acids primarily eicosapentaenoic and docosahexaenoic fatty acids. Metabolites of these two polyunsaturated fatty acids include the E and D series resolvins. Omega-3 polyunsaturated fatty acids and resolvins have been reported to have anti-inflammatory and neuroprotective properties. The objective of this study was to evaluate the efficacy of menhaden oil, a fish oil derived from the menhaden, resolvins D1 and E1 and the methyl esters of resolvins D1 and D2 on diabetic peripheral neuropathy. Hypothesis being examined was that the methyl esters of resolvins D1 and D2 would be move efficacious than resolvins D1 or E1 due to an extended half-life. Methods A model of type 2 diabetes in C57BL/6J mice was created through a combination of a high fat diet followed 8 weeks later with treatment of low dosage of streptozotocin. After 8 weeks of untreated hyperglycemia type 2 diabetic mice were treated for 8 weeks with menhaden oil in the diet or daily injections of 1 ng/g body weight resolvins D1, E1 or methyl esters of resolvins D1 or D2. Afterwards, multiple neurological endpoints were examined. Results Menhaden oil or resolvins did not improve hyperglycemia. Untreated diabetic mice were thermal hypoalgesic, had mechanical allodynia, reduced motor and sensory nerve conduction velocities and decreased innervation of the cornea and skin. These endpoints were significantly improved with menhaden oil or resolvin treatment. However, the methyl esters of resolvins D1 or D2, contrary to our hypothesis, were generally less potent than menhaden oil or resolvins D1 or E1. Conclusion These studies further support omega-3 polyunsaturated fatty acids derived from fish oil via in part due to their metabolites could be an effective treatment for diabetic neuropathy.
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Affiliation(s)
| | | | - Hanna Shevalye
- Department of Internal Medicine, University of Iowa, Iowa City, USA
| | - Mark A Yorek
- Department of Internal Medicine, University of Iowa, Iowa City, USA.,Department of Veterans Affairs, Iowa City Health Care System, Iowa City, USA.,Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, USA
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Bessaguet F, Danigo A, Magy L, Sturtz F, Desmoulière A, Demiot C. Candesartan prevents resiniferatoxin-induced sensory small-fiber neuropathy in mice by promoting angiotensin II-mediated AT2 receptor stimulation. Neuropharmacology 2017; 126:142-150. [PMID: 28882562 DOI: 10.1016/j.neuropharm.2017.08.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/04/2017] [Accepted: 08/31/2017] [Indexed: 12/27/2022]
Abstract
Sensory defects associated with small-fiber neuropathy (SFN) can lead to profound disabilities. The relationship between the sensory nervous system and modulation of the renin-angiotensin system (RAS) has been described and focused on pain and neurodegeneration in several animal models. We have recently developed an experimental model of functional sensory neuropathy showing thermal hypoalgesia and neuropeptide depletion without nerve fiber degeneration. Here, we aimed to determine whether the modulation of angiotensin II (Ang II) activity could prevent sensory neuropathy induced by RTX. Control and RTX mice received ramipril, an Ang II converting enzyme (ACE) inhibitor, (0.5 mg/kg/day) or candesartan, an Ang II type 1 receptor (AT1R) blocker (0.5 mg/kg/day), one day before vehicle or RTX administration, and each day for the next seven days. Ramipril did not have a beneficial effect in RTX mice, whereas candesartan prevented thermal hypoalgesia and reduced neuropeptide depletion in intraepidermal nerve fibers and dorsal root ganglion neurons. The preventive effect of candesartan was not observed in mice deficient for the Ang II type 2 receptor (AT2R) and was counteracted in wild type mice by EMA200, an AT2R antagonist (3 mg/kg/day). Thus, candesartan may promote AT2R activation by blocking AT1R and increasing Ang II production and enhance its mechanisms of neuroprotection in our RTX model. Our finding that candesartan prevents nociception deficits and neuropeptide depletion encourages the evaluation of its therapeutic potential in patients presenting SFN, particularly those who experience chemotherapy-induced SFN.
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Affiliation(s)
- Flavien Bessaguet
- EA 6309 - Myelin Maintenance & Peripheral Neuropathy, Faculties of Medicine and Pharmacy, University of Limoges, Limoges, France
| | - Aurore Danigo
- EA 6309 - Myelin Maintenance & Peripheral Neuropathy, Faculties of Medicine and Pharmacy, University of Limoges, Limoges, France
| | - Laurent Magy
- Department of Neurology, Reference Center for Rare Peripheral Neuropathies, University Hospital of Limoges, Limoges, France
| | - Franck Sturtz
- EA 6309 - Myelin Maintenance & Peripheral Neuropathy, Faculties of Medicine and Pharmacy, University of Limoges, Limoges, France
| | - Alexis Desmoulière
- EA 6309 - Myelin Maintenance & Peripheral Neuropathy, Faculties of Medicine and Pharmacy, University of Limoges, Limoges, France
| | - Claire Demiot
- EA 6309 - Myelin Maintenance & Peripheral Neuropathy, Faculties of Medicine and Pharmacy, University of Limoges, Limoges, France.
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He J, Pham TL, Kakazu A, Bazan HEP. Recovery of Corneal Sensitivity and Increase in Nerve Density and Wound Healing in Diabetic Mice After PEDF Plus DHA Treatment. Diabetes 2017; 66:2511-2520. [PMID: 28592408 PMCID: PMC5566302 DOI: 10.2337/db17-0249] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/31/2017] [Indexed: 12/26/2022]
Abstract
Diabetic keratopathy decreases corneal sensation and tear secretion and delays wound healing after injury. In the current study, we tested the effect of treatment with pigment epithelium-derived factor (PEDF) in combination with docosahexaenoic acid (DHA) on corneal nerve regeneration in a mouse model of diabetes with or without corneal injury. The study was performed in streptozotocin-induced diabetic mice (C57BL/6). Ten weeks after streptozotocin injection, diabetic mice showed significant decreases of corneal sensitivity, tear production, and epithelial subbasal nerve density when compared with age-matched normal mice. After diabetic mice were wounded in the right eye and treated in both eyes with PEDF+DHA for 2 weeks, there was a significant increase in corneal epithelial nerve regeneration and substance P-positive nerve density in both wounded and unwounded eyes compared with vehicle-treated corneas. There also was elevated corneal sensitivity and tear production in the treated corneas compared with vehicle. In addition, PEDF+DHA accelerated corneal wound healing, selectively recruited type 2 macrophages, and prevented neutrophil infiltration in diabetic wounded corneas. These results suggest that topical treatment with PEDF+DHA promotes corneal nerve regeneration and wound healing in diabetic mice and could potentially be exploited as a therapeutic option for the treatment of diabetic keratopathy.
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Affiliation(s)
- Jiucheng He
- Neuroscience Center of Excellence and Department of Ophthalmology, School of Medicine, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA
| | - Thang Luong Pham
- Neuroscience Center of Excellence and Department of Ophthalmology, School of Medicine, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA
| | - Azucena Kakazu
- Neuroscience Center of Excellence and Department of Ophthalmology, School of Medicine, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA
| | - Haydee E P Bazan
- Neuroscience Center of Excellence and Department of Ophthalmology, School of Medicine, Louisiana State University Health Sciences Center New Orleans, New Orleans, LA
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Abstract
PURPOSE To determine tear neuropeptide levels in contact lens wearers and non-wearers, and to examine relationships with indices of corneal innervation, tear function, and ocular discomfort. METHODS A cross-sectional, single-visit, investigator-masked pilot study. Assessments included Ocular Comfort Index (OCI), central and mid-peripheral corneal nerve density and morphology (HRT-Rostock), corneal sensitivity (Cochet-Bonnet aesthesiometer), tear Substance P and calcitonin gene-related peptide (CGRP) concentration (ELISA), in situ tear osmolarity (TearLab), tear secretion (Phenol Red Thread), and noninvasive tear break-up time (NITBUT; Keeler Tearscope). Groups were compared using independent t-test or Mann-Whitney U test, and regional differences assessed using paired t-tests. Associations were analyzed using Pearson or Spearman correlation. Significance was determined at P < .05. RESULTS Twenty contact lens wearers (7M:13F, 32 ± 5 years) and 20 non-wearers (7M:13F, 31 ± 5 years) completed the study. OCI score was numerically higher in lens wearers (32.27 ± 5.33) than non-wearers (27.66 ± 9.94). Tear osmolarity was higher [298.0 (IQR 291.0-309.8) vs. 288.5 (282.3-298.3) mOsmol/L; P = .01] whereas NITBUT was lower (9.8 ± 3.4 vs. 13.8 ± 5.6 s; P = .01) in lens wearers compared with non-wearers. Tear neuropeptide concentrations were not different between groups [Substance P 4.29 ng/ml (IQR 1.57-6.05), CGRP 14.89 ng/ml (5.08-59.26)], and there were no differences in nerve morphology or ocular surface sensitivity. Higher nerve density, interconnections, and tortuosity were observed in the central cornea than mid-peripherally (P < .05). OCI score was moderately associated with nerve tortuosity (r = 0.42, P = .01). CGRP was associated with central nerve density (ρ = 0.38, P = .02), as was tear secretion (r = -0.37, P = .02). Nerve interconnections were strongly associated with corneal sensitivity (ρ = 0.64, P < .001). CONCLUSIONS Relationships were demonstrated between nerve density, tear CGRP, and corneal sensitivity. Markers of corneal neurobiology and sensory function do not appear to be altered in contact lens wear despite worse tear function (osmolarity and stability) in lens wearers. This suggests that mechanisms other than overt changes in corneal innervation regulate tear function during lens wear. The relationship between nerve tortuosity and ocular discomfort requires elucidation.
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Sullivan DA, Rocha EM, Aragona P, Clayton JA, Ding J, Golebiowski B, Hampel U, McDermott AM, Schaumberg DA, Srinivasan S, Versura P, Willcox MDP. TFOS DEWS II Sex, Gender, and Hormones Report. Ocul Surf 2017; 15:284-333. [PMID: 28736336 DOI: 10.1016/j.jtos.2017.04.001] [Citation(s) in RCA: 232] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 04/16/2017] [Indexed: 12/21/2022]
Abstract
One of the most compelling features of dry eye disease (DED) is that it occurs more frequently in women than men. In fact, the female sex is a significant risk factor for the development of DED. This sex-related difference in DED prevalence is attributed in large part to the effects of sex steroids (e.g. androgens, estrogens), hypothalamic-pituitary hormones, glucocorticoids, insulin, insulin-like growth factor 1 and thyroid hormones, as well as to the sex chromosome complement, sex-specific autosomal factors and epigenetics (e.g. microRNAs). In addition to sex, gender also appears to be a risk factor for DED. "Gender" and "sex" are words that are often used interchangeably, but they have distinct meanings. "Gender" refers to a person's self-representation as a man or woman, whereas "sex" distinguishes males and females based on their biological characteristics. Both gender and sex affect DED risk, presentation of the disease, immune responses, pain, care-seeking behaviors, service utilization, and myriad other facets of eye health. Overall, sex, gender and hormones play a major role in the regulation of ocular surface and adnexal tissues, and in the difference in DED prevalence between women and men. The purpose of this Subcommittee report is to review and critique the nature of this role, as well as to recommend areas for future research to advance our understanding of the interrelationships between sex, gender, hormones and DED.
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Affiliation(s)
- David A Sullivan
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA.
| | - Eduardo M Rocha
- Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Pasquale Aragona
- Department of Biomedical Sciences, Ocular Surface Diseases Unit, University of Messina, Messina, Sicily, Italy
| | - Janine A Clayton
- National Institutes of Health Office of Research on Women's Health, Bethesda, MD, USA
| | - Juan Ding
- Schepens Eye Research Institute, Massachusetts Eye & Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Blanka Golebiowski
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
| | - Ulrike Hampel
- Department of Ophthalmology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Alison M McDermott
- The Ocular Surface Institute, College of Optometry, University of Houston, Houston, TX, USA
| | - Debra A Schaumberg
- Harvard School of Public Health, Boston, MA, USA; University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Sruthi Srinivasan
- Centre for Contact Lens Research, School of Optometry, University of Waterloo, Ontario, Canada
| | - Piera Versura
- Department of Specialized, Experimental, and Diagnostic Medicine, University of Bologna, Bologna, Italy
| | - Mark D P Willcox
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
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Yorek MS, Davidson EP, Poolman P, Coppey LJ, Obrosov A, Holmes A, Kardon RH, Yorek MA. Corneal Sensitivity to Hyperosmolar Eye Drops: A Novel Behavioral Assay to Assess Diabetic Peripheral Neuropathy. Invest Ophthalmol Vis Sci 2017; 57:2412-9. [PMID: 27145474 PMCID: PMC5113984 DOI: 10.1167/iovs.16-19435] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Purpose Diagnosis of peripheral neuropathy (PN), which affects approximately 50% of the diabetic population, is subjective, with many patients seeking a diagnosis only after presenting with symptoms. Recently, in vivo confocal microscopy of subepithelial corneal nerve density has been promoted as a surrogate marker for early detection of PN, but imaging of corneal nerves requires sophisticated instrumentation, expertise in confocal imaging, cooperative patients, and automated analysis tools to derive corneal nerve density. As an alternative, we developed a simple screening method that is based on the sensitivity of corneal nerves to cause reflex eyelid squinting in response to hyperosmolar eye drops. Methods Eyes of control and type 2 diabetic rats were given an eye drop of a 290- to 900-mOsm solution, and the ocular response was video recorded. Other neuropathic end points including nerve conduction velocity and subepithelial cornea nerve density were determined. Results Motor and sensory nerve conduction velocity and total nerve fiber length of corneal nerves in the subepithelial layer were significantly decreased in diabetic rats. Applying the hyperosmotic solutions to the ocular surface caused an osmolarity-dependent increase in squinting of the treated eye in control rats. Squinting was almost totally blocked by preapplication of proparacaine or N-(4-tertiarybutylphenyl)-4-(3-chloropyridin-2-yl)tetrahydropyrazine-1(2H)-carbox-amide, a transient receptor potential melastatin-8 channel blocker. Squinting in response to the 900-mOsm solution was significantly reduced in diabetic rats. Conclusions Preclinical studies show that evaluation of corneal sensitivity may be an alternative method for the early detection of PN and has potential for translation to clinical studies.
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Affiliation(s)
- Matthew S Yorek
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa, United States 2Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States
| | - Eric P Davidson
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
| | - Pieter Poolman
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa, United States 2Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States 4Department of Ophthalmology and Visual Sciences, Universi
| | - Lawrence J Coppey
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
| | - Alexander Obrosov
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States
| | - Amey Holmes
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa, United States
| | - Randy H Kardon
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa, United States 2Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States 4Department of Ophthalmology and Visual Sciences, Universi
| | - Mark A Yorek
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa, United States 2Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States 3Department of Internal Medicine, University of Iowa, Iowa
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A systematic review on the impact of diabetes mellitus on the ocular surface. Nutr Diabetes 2017; 7:e251. [PMID: 28319106 PMCID: PMC5380897 DOI: 10.1038/nutd.2017.4] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/10/2016] [Accepted: 11/14/2016] [Indexed: 12/27/2022] Open
Abstract
Diabetes mellitus is associated with extensive morbidity and mortality in any human community. It is well understood that the burden of diabetes is attributed to chronic progressive damage in major end-organs, but it is underappreciated that the most superficial and transparent organ affected by diabetes is the cornea. Different corneal components (epithelium, nerves, immune cells and endothelium) underpin specific systemic complications of diabetes. Just as diabetic retinopathy is a marker of more generalized microvascular disease, corneal nerve changes can predict peripheral and autonomic neuropathy, providing a window of opportunity for early treatment. In addition, alterations of immune cells in corneas suggest an inflammatory component in diabetic complications. Furthermore, impaired corneal epithelial wound healing may also imply more widespread disease. The non-invasiveness and improvement in imaging technology facilitates the emergence of new screening tools. Systemic control of diabetes can improve ocular surface health, possibly aided by anti-inflammatory and vasoprotective agents.
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Yorek MS, Obrosov A, Shevalye H, Coppey LJ, Kardon RH, Yorek MA. Early vs. late intervention of high fat/low dose streptozotocin treated C57Bl/6J mice with enalapril, α-lipoic acid, menhaden oil or their combination: Effect on diabetic neuropathy related endpoints. Neuropharmacology 2016; 116:122-131. [PMID: 28025096 DOI: 10.1016/j.neuropharm.2016.12.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 11/28/2016] [Accepted: 12/21/2016] [Indexed: 01/06/2023]
Abstract
We have previously demonstrated that enalapril, α-lipoic acid and menhaden (fish) oil has potential as a treatment for diabetic peripheral neuropathy. In this study we sought to determine the efficacy of these treatments individually or in combination on multiple neuropathic endpoints in a high fat fed low dose streptozotocin treated mouse, a model of type 2 diabetes, following early or late intervention. Four or twelve weeks after the onset of hyperglycemia, diabetic mice were treated with enalapril, α-lipoic acid, menhaden oil or their combination for 12 weeks. Afterwards, endpoints including glucose tolerance, motor and sensory nerve conduction velocity, thermal nociception, and intraepidermal and cornea nerve fiber density was determined. Glucose clearance was impaired in diabetic mice and significantly improved only with combination treatment and early intervention. Diabetes caused steatosis, slowing of motor and sensory nerve conduction velocity, thermal hypoalgesia and reduction in intraepidermal and cornea nerve fiber density. Treating diabetic mice with enalapril, α-lipoic acid or menhaden oil partially protected diabetic mice from these deficits, whereas the combination of these three treatments was more efficacious following early or late intervention. These studies suggest that a combination therapy may be more effective for treating neural complications of type 2 diabetes.
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Affiliation(s)
- Matthew S Yorek
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA, 52246, USA; Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA, 52246, USA.
| | - Alexander Obrosov
- Department of Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA.
| | - Hanna Shevalye
- Department of Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA.
| | - Lawrence J Coppey
- Department of Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA.
| | - Randy H Kardon
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA, 52246, USA; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, 52242, USA; Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA, 52246, USA.
| | - Mark A Yorek
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA, 52246, USA; Department of Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA; Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA, 52246, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, 52242, USA.
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Neuronal Changes in the Diabetic Cornea: Perspectives for Neuroprotection. BIOMED RESEARCH INTERNATIONAL 2016; 2016:5140823. [PMID: 28044131 PMCID: PMC5156788 DOI: 10.1155/2016/5140823] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 10/14/2016] [Accepted: 10/23/2016] [Indexed: 01/17/2023]
Abstract
Diabetic neuropathy is associated with neurotrophic ulcerations of the skin and cornea. Decreased corneal sensitivity and impaired innervation lead to weakened epithelial wound healing predisposing patients to ocular complications such as corneal infections, stromal opacification, and surface irregularity. This review presents recent findings on impaired corneal innervation in diabetic individuals, and the findings suggest that corneal neuropathy might be an early indicator of diabetic neuropathy. Additionally, the recent findings for neuroprotective and regenerative therapy for diabetic keratopathy are presented.
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Yorek MS, Obrosov A, Lu B, Gerard C, Kardon RH, Yorek MA. Effect of Inhibition or Deletion of Neutral Endopeptidase on Neuropathic Endpoints in High Fat Fed/Low Dose Streptozotocin-Treated Mice. J Neuropathol Exp Neurol 2016; 75:1072-1080. [PMID: 27634964 PMCID: PMC7714044 DOI: 10.1093/jnen/nlw083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Previously we demonstrated that a vasopeptidase inhibitor of angiotensin converting enzyme and neutral endopeptidase (NEP), a protease that degrades vaso- and neuro-active peptides, improves neural function in diabetic rodent models. The purpose of this study was to determine whether inhibition or deletion of NEP provides protection from neuropathy caused by diabetes with an emphasis on morphology of corneal nerves as a primary endpoint. Diabetes, modeling type 2, was induced in C57Bl/6J and NEP deficient mice through a combination of a high fat diet and streptozotocin. To inhibit NEP activity, diabetic C57Bl/6J mice were treated with candoxatril using a prevention or intervention protocol. Twelve weeks after the induction of diabetes in C57Bl/6J mice, the existence of diabetic neuropathy was determined through multiple endpoints including decrease in corneal nerves in the epithelium and sub-epithelium layer. Treatment of diabetic C57Bl/6J mice with candoxatril improved diabetic peripheral neuropathy and protected corneal nerve morphology with the prevention protocol being more efficacious than intervention. Unlike C57Bl/6J, mice deficient in NEP were protected from the development of neuropathologic alterations and loss of corneal nerves upon induction of diabetes. These studies suggest that NEP contributes to the development of diabetic neuropathy and may be a treatable target.
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Affiliation(s)
- Matthew S Yorek
- From the Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA(MSY, RHK, MAY), Department of Internal Medicine, University of Iowa, Iowa City, IA(AO, MAY), Department of Pediatrics and Medicine, Harvard Medical School, Ina Sue Perlmutter Laboratory, Children's Hospital, Boston, MA(BL), Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA(RHK), Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA(RHK, MAY) and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA(MAY)
| | - Alexander Obrosov
- From the Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA(MSY, RHK, MAY), Department of Internal Medicine, University of Iowa, Iowa City, IA(AO, MAY), Department of Pediatrics and Medicine, Harvard Medical School, Ina Sue Perlmutter Laboratory, Children's Hospital, Boston, MA(BL), Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA(RHK), Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA(RHK, MAY) and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA(MAY)
| | - Bao Lu
- From the Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA(MSY, RHK, MAY), Department of Internal Medicine, University of Iowa, Iowa City, IA(AO, MAY), Department of Pediatrics and Medicine, Harvard Medical School, Ina Sue Perlmutter Laboratory, Children's Hospital, Boston, MA(BL), Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA(RHK), Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA(RHK, MAY) and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA(MAY)
| | - Craig Gerard
- From the Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA(MSY, RHK, MAY), Department of Internal Medicine, University of Iowa, Iowa City, IA(AO, MAY), Department of Pediatrics and Medicine, Harvard Medical School, Ina Sue Perlmutter Laboratory, Children's Hospital, Boston, MA(BL), Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA(RHK), Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA(RHK, MAY) and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA(MAY)
| | - Randy H Kardon
- From the Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA(MSY, RHK, MAY), Department of Internal Medicine, University of Iowa, Iowa City, IA(AO, MAY), Department of Pediatrics and Medicine, Harvard Medical School, Ina Sue Perlmutter Laboratory, Children's Hospital, Boston, MA(BL), Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA(RHK), Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA(RHK, MAY) and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA(MAY)
| | - Mark A Yorek
- From the Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA(MSY, RHK, MAY), Department of Internal Medicine, University of Iowa, Iowa City, IA(AO, MAY), Department of Pediatrics and Medicine, Harvard Medical School, Ina Sue Perlmutter Laboratory, Children's Hospital, Boston, MA(BL), Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA(RHK), Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA(RHK, MAY) and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA(MAY)
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Sassani JW, Mc Laughlin PJ, Zagon IS. The Yin and Yang of the Opioid Growth Regulatory System: Focus on Diabetes-The Lorenz E. Zimmerman Tribute Lecture. J Diabetes Res 2016; 2016:9703729. [PMID: 27703986 PMCID: PMC5039296 DOI: 10.1155/2016/9703729] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 04/24/2016] [Indexed: 12/16/2022] Open
Abstract
The Opioid Growth Regulatory System consists of opioid growth factor (OGF), [Met5]-enkephalin, and its unique receptor (OGFr). OGF inhibits cell division when bound to OGFr. Conversely, blockade of the interaction of OGF and OGFr, using the potent, long-acting opioid receptor antagonist, naltrexone (NTX), results in increased DNA synthesis and cell division. The authors have demonstrated both in vitro and in vivo that the addition of exogenous OGF or an increase in available OGFr decreases corneal epithelial cell division and wound healing. Conversely, blockade of the OGF-OGFr interaction by NTX or a decrease in the production of the OGFr increases corneal epithelial cell division and facilitates corneal epithelial wound healing. The authors also have demonstrated that depressed corneal and cutaneous wound healing, dry eye, and abnormal corneal sensitivity in type 1 and type 2 diabetes in animals can be reversed by OGF-OGFr blockade by NTX. Thus, the function of the Opioid Growth Regulatory System appears to be disordered in diabetic animals, and its function can be restored with NTX treatment. These studies suggest a fundamental role for the Opioid Growth Regulatory System in the pathobiology of diabetic complications and a need for studies to elucidate this role further.
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Affiliation(s)
- Joseph W. Sassani
- Departments of Ophthalmology and Pathology, Penn State Milton S. Hershey Medical Center, Hershey, PA 17033, USA
| | - Patricia J. Mc Laughlin
- Department of Neural and Behavioral Sciences, The Penn State University College of Medicine, Hershey, PA 17033, USA
| | - Ian S. Zagon
- Department of Neural and Behavioral Sciences, The Penn State University College of Medicine, Hershey, PA 17033, USA
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Gao N, Yan C, Lee P, Sun H, Yu FS. Dendritic cell dysfunction and diabetic sensory neuropathy in the cornea. J Clin Invest 2016; 126:1998-2011. [PMID: 27064280 DOI: 10.1172/jci85097] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 02/24/2016] [Indexed: 12/11/2022] Open
Abstract
Diabetic peripheral neuropathy (DPN) often leads to neurotrophic ulcerations in the cornea and skin; however, the underlying cellular mechanisms of this complication are poorly understood. Here, we used post-wound corneal sensory degeneration and regeneration as a model and tested the hypothesis that diabetes adversely affects DC populations and infiltration, resulting in disrupted DC-nerve communication and DPN. In streptozotocin-induced type 1 diabetic mice, there was a substantial reduction in sensory nerve density and the number of intraepithelial DCs in unwounded (UW) corneas. In wounded corneas, diabetes markedly delayed sensory nerve regeneration and reduced the number of infiltrating DCs, which were a major source of ciliary neurotrophic factor (CNTF) in the cornea. While CNTF neutralization retarded reinnervation in normal corneas, exogenous CNTF accelerated nerve regeneration in the wounded corneas of diabetic mice and healthy animals, in which DCs had been locally depleted. Moreover, blockade of the CNTF-specific receptor CNTFRα induced sensory nerve degeneration and retarded regeneration in normal corneas. Soluble CNTFRα also partially restored the branching of diabetes-suppressed sensory nerve endings and regeneration in the diabetic corneas. Collectively, our data show that DCs mediate sensory nerve innervation and regeneration through CNTF and that diabetes reduces DC populations in UW and wounded corneas, resulting in decreased CNTF and impaired sensory nerve innervation and regeneration.
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Yorek MS, Obrosov A, Shevalye H, Lupachyk S, Harper MM, Kardon RH, Yorek MA. Effect of glycemic control on corneal nerves and peripheral neuropathy in streptozotocin-induced diabetic C57Bl/6J mice. J Peripher Nerv Syst 2015; 19:205-17. [PMID: 25403729 DOI: 10.1111/jns.12086] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/02/2014] [Accepted: 06/04/2014] [Indexed: 01/09/2023]
Abstract
We sought to determine the impact that duration of hyperglycemia and control has on corneal nerve fiber density in relation to standard diabetic neuropathy endpoints. Control and streptozotocin-diabetic C57Bl/6J mice were analyzed after 4, 8, 12, and 20 weeks. For the 20-week time point, five groups of mice were compared: control, untreated diabetic, and diabetic treated with insulin designated as having either poor glycemic control, good glycemic control, or poor glycemic control switched to good glycemic control. Hyperglycemia was regulated by use of insulin-releasing pellets. Loss of corneal nerves in the sub-epithelial nerve plexus or corneal epithelium progressed slowly in diabetic mice requiring 20 weeks to reach statistical significance. In comparison, slowing of motor and sensory nerve conduction velocity developed rapidly with significant difference compared with control mice observed after 4 and 8 weeks of hyperglycemia, respectively. In diabetic mice with good glycemic control, average blood glucose levels over the 20-week experimental period were lowered from 589 ± 2 to 251 ± 9 mg/dl. All diabetic neuropathy endpoints examined were improved in diabetic mice with good glycemic control compared with untreated diabetic mice. However, good control of blood glucose was not totally sufficient in preventing diabetic neuropathy.
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Affiliation(s)
- Matthew S Yorek
- Department of Veterans Affairs, Iowa City Health Care System, Iowa City, IA, USA; Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, IA, USA
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Petropoulos IN, Ferdousi M, Marshall A, Alam U, Ponirakis G, Azmi S, Fadavi H, Efron N, Tavakoli M, Malik RA. The Inferior Whorl For Detecting Diabetic Peripheral Neuropathy Using Corneal Confocal Microscopy. Invest Ophthalmol Vis Sci 2015; 56:2498-504. [PMID: 25783609 DOI: 10.1167/iovs.14-15919] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE In vivo corneal confocal microscopy (CCM) is increasingly used as a surrogate endpoint in studies of diabetic polyneuropathy (DPN). However, it is not clear whether imaging the central cornea provides optimal diagnostic utility for DPN. Therefore, we compared nerve morphology in the central cornea and the inferior whorl, a more distal and densely innervated area located inferior and nasal to the central cornea. METHODS A total of 53 subjects with type 1/type 2 diabetes and 15 age-matched control subjects underwent detailed assessment of neuropathic symptoms (NPS), deficits (neuropathy disability score [NDS]), quantitative sensory testing (vibration perception threshold [VPT], cold and warm threshold [CT/WT], and cold- and heat-induced pain [CIP/HIP]), and electrophysiology (sural and peroneal nerve conduction velocity [SSNCV/PMNCV], and sural and peroneal nerve amplitude [SSNA/PMNA]) to diagnose patients with (DPN+) and without (DPN-) neuropathy. Corneal nerve fiber density (CNFD) and length (CNFL) in the central cornea, and inferior whorl length (IWL) were quantified. RESULTS Comparing control subjects to DPN- and DPN+ patients, there was a significant increase in NDS (0 vs. 2.6 ± 2.3 vs. 3.3 ± 2.7, P < 0.01), VPT (V; 5.4 ± 3.0 vs. 10.6 ± 10.3 vs. 17.7 ± 11.8, P < 0.01), WT (°C; 37.7 ± 3.5 vs. 39.1 ± 5.1 vs. 41.7 ± 4.7, P < 0.05), and a significant decrease in SSNCV (m/s; 50.2 ± 5.4 vs. 48.4 ± 5.0 vs. 39.5 ± 10.6, P < 0.05), CNFD (fibers/mm2; 37.8 ± 4.9 vs. 29.7 ± 7.7 vs. 27.1 ± 9.9, P < 0.01), CNFL (mm/mm2; 27.5 ± 3.6 vs. 24.4 ± 7.8 vs. 20.7 ± 7.1, P < 0.01), and IWL (mm/mm2; 35.1 ± 6.5 vs. 26.2 ± 10.5 vs. 23.6 ± 11.4, P < 0.05). For the diagnosis of DPN, CNFD, CNFL, and IWL achieved an area under the curve (AUC) of 0.75, 0.74, and 0.70, respectively, and a combination of IWL-CNFD achieved an AUC of 0.76. CONCLUSIONS The parameters of CNFD, CNFL, and IWL have a comparable ability to diagnose patients with DPN. However, IWL detects an abnormality even in patients without DPN. Combining IWL with CNFD may improve the diagnostic performance of CCM.
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Affiliation(s)
- Ioannis N Petropoulos
- Division of Medicine, Weill Cornell Medical College-Qatar, Qatar Foundation, Education City, Doha, Qatar 2Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centr
| | - Maryam Ferdousi
- Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Andrew Marshall
- Clinical Neurophysiology, Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Uazman Alam
- Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Georgios Ponirakis
- Division of Medicine, Weill Cornell Medical College-Qatar, Qatar Foundation, Education City, Doha, Qatar 2Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centr
| | - Shazli Azmi
- Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Hassan Fadavi
- Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Nathan Efron
- Queensland University of Technology, School of Optometry and Vision Science, Brisbane, Australia
| | - Mitra Tavakoli
- Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Rayaz A Malik
- Division of Medicine, Weill Cornell Medical College-Qatar, Qatar Foundation, Education City, Doha, Qatar 2Centre for Endocrinology and Diabetes, University of Manchester and Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centr
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Davidson EP, Holmes A, Coppey LJ, Yorek MA. Effect of combination therapy consisting of enalapril, α-lipoic acid, and menhaden oil on diabetic neuropathy in a high fat/low dose streptozotocin treated rat. Eur J Pharmacol 2015; 765:258-67. [PMID: 26291662 DOI: 10.1016/j.ejphar.2015.08.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 01/20/2023]
Abstract
We have previously demonstrated that treating diabetic rats with enalapril, an angiotensin converting enzyme (ACE) inhibitor, α-lipoic acid, an antioxidant, or menhaden oil, a natural source of omega-3 fatty acids can partially improve diabetic peripheral neuropathy. In this study we sought to determine the efficacy of combining these three treatments on vascular and neural complications in a high fat fed low dose streptozotocin treated rat, a model of type 2 diabetes. Rats were fed a high fat diet for 8 weeks followed by a 30 mg/kg dose of streptozotocin. Eight weeks after the onset of hyperglycemia diabetic rats were treated with a combination of enalapril, α-lipoic acid and menhaden oil. Diabetic rats not receiving treatment were continued on the high fat diet. Glucose clearance was impaired in diabetic rats and significantly improved with treatment. Diabetes caused steatosis, elevated serum lipid levels, slowing of motor and sensory nerve conduction, thermal hypoalgesia, reduction in intraepidermal nerve fiber profiles, decrease in cornea sub-basal nerve fiber length and corneal sensitivity and impairment in vascular relaxation to acetylcholine and calcitonin gene-related peptide in epineurial arterioles of the sciatic nerve. Treating diabetic rats with the combination of enalapril, α-lipoic acid and menhaden oil reversed all these deficits to near control levels except for motor nerve conduction velocity which was also significantly improved compared to diabetic rats but remained significantly decreased compared to control rats. These studies suggest that a combination therapeutic approach may be most effective for treating vascular and neural complications of type 2 diabetes.
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Affiliation(s)
- Eric P Davidson
- Department of Internal Medicine, University of Iowa, Iowa City, 52242 IA, USA
| | - Amey Holmes
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, 52246 IA, USA
| | - Lawrence J Coppey
- Department of Internal Medicine, University of Iowa, Iowa City, 52242 IA, USA
| | - Mark A Yorek
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, 52246 IA, USA; Department of Internal Medicine, University of Iowa, Iowa City, 52242 IA, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, 52242 IA, USA.
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Yorek MA. Vascular Impairment of Epineurial Arterioles of the Sciatic Nerve: Implications for Diabetic Peripheral Neuropathy. Rev Diabet Stud 2015; 12:13-28. [PMID: 26676659 PMCID: PMC5397981 DOI: 10.1900/rds.2015.12.13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 04/30/2015] [Indexed: 12/11/2022] Open
Abstract
This article reviews the impact of diabetes and its treatment on vascular function with a focus on the reactivity of epineurial arterioles, blood vessels that provide circulation to the sciatic nerve. Another focus is the relationship between the dysregulation of neurovascular function and diabetic peripheral neuropathy. Diabetic peripheral neuropathy is a debilitating disorder that occurs in more than 50 percent of patients with diabetes. The etiology involves metabolic, vascular, and immunologic pathways besides neurohormonal growth factor deficiency and extracellular matrix remodeling. In the light of this complex etiology, an effective treatment for diabetic peripheral neuropathy has not yet been identified. Current opinion postulates that any effective treatment for diabetic peripheral neuropathy will require a combination of life style and therapeutic interventions. However, a more comprehensive understanding of the factors contributing to neurovascular and neural dysfunction in diabetes is needed before such a treatment strategy can be developed. After reading this review, the reader should have gained insight into the complex regulation of vascular function and blood flow to the sciatic nerve, and the impact of diabetes on numerous elements of vascular reactivity of epineurial arterioles of the sciatic nerve.
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Affiliation(s)
- Mark A Yorek
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, IA 52246, USA
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Shevalye H, Yorek MS, Coppey LJ, Holmes A, Harper MM, Kardon RH, Yorek MA. Effect of enriching the diet with menhaden oil or daily treatment with resolvin D1 on neuropathy in a mouse model of type 2 diabetes. J Neurophysiol 2015; 114:199-208. [PMID: 25925322 DOI: 10.1152/jn.00224.2015] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 04/24/2015] [Indexed: 12/14/2022] Open
Abstract
The purpose of this study was to determine the effect of supplementing the diet of a mouse model of type 2 diabetes with menhaden (fish) oil or daily treatment with resolvin D1 on diabetic neuropathy. The end points evaluated included motor and sensory nerve conduction velocity, thermal sensitivity, innervation of sensory nerves in the cornea and skin, and the retinal ganglion cell complex thickness. Menhaden oil is a natural source for n-3 polyunsaturated fatty acids, which have been shown to have beneficial effects in other diseases. Resolvin D1 is a metabolite of docosahexaenoic acid and is known to have anti-inflammatory and neuroprotective properties. To model type 2 diabetes, mice were fed a high-fat diet for 8 wk followed by a low dosage of streptozotocin. After 8 wk of hyperglycemia, mice in experimental groups were treated for 6 wk with menhaden oil in the diet or daily injections of 1 ng/g body wt resolvin D1. Our findings show that menhaden oil or resolvin D1 did not improve elevated blood glucose, HbA1C, or glucose utilization. Untreated diabetic mice were thermal hypoalgesic, had reduced motor and sensory nerve conduction velocities, had decreased innervation of the cornea and skin, and had thinner retinal ganglion cell complex. These end points were significantly improved with menhaden oil or resolvin D1 treatment. Exogenously, resolvin D1 stimulated neurite outgrowth from primary cultures of dorsal root ganglion neurons from normal mice. These studies suggest that n-3 polyunsaturated fatty acids derived from fish oil could be an effective treatment for diabetic neuropathy.
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Affiliation(s)
- Hanna Shevalye
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa
| | - Matthew S Yorek
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa; Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa; and
| | - Lawrence J Coppey
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa
| | - Amey Holmes
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa
| | - Matthew M Harper
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa; Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa; and
| | - Randy H Kardon
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa; Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa; and
| | - Mark A Yorek
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa; Department of Internal Medicine, University of Iowa, Iowa City, Iowa; Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa; and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
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Nishida T, Inui M, Nomizu M. Peptide therapies for ocular surface disturbances based on fibronectin-integrin interactions. Prog Retin Eye Res 2015; 47:38-63. [PMID: 25645519 DOI: 10.1016/j.preteyeres.2015.01.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 01/18/2015] [Accepted: 01/21/2015] [Indexed: 11/24/2022]
Abstract
The condition of the corneal epithelium is a critical determinant of corneal transparency and clear vision. The corneal epithelium serves as a barrier to protect the eye from external insults, with its smooth surface being essential for its optical properties. Disorders of the corneal epithelium include superficial punctate keratopathy, corneal erosion, and persistent epithelial defects (PEDs). The prompt resolution of these disorders is important for minimization of further damage to the cornea. Currently available treatment modalities for corneal epithelial disorders are based on protection of the ocular surface in order to allow natural healing to proceed. PEDs remain among the most difficult corneal conditions to treat, however. On the basis of characterization of the pathobiology of PEDs at the cell and molecular biological levels, we have strived to develop new modes of treatment for these defects. These treatments rely on two key concepts: provision of a substrate, such as the adhesive glycoprotein fibronectin, for the attachment and migration of corneal epithelial cells, and activation of these cells by biological agents such as the combination of substance P and insulin-like growth factor-1 (IGF-1). Central to both approaches is the role of the fibronectin-integrin system in corneal epithelial wound healing. Determination of the minimum amino acid sequences required for the promotion of corneal epithelial wound closure by fibronectin (PHSRN) and by substance P (FGLM-amide) plus IGF-1 (SSSR) has led to the development of peptide eyedrops for the treatment of PEDs that are free of adverse effects of the parent molecules.
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Affiliation(s)
- Teruo Nishida
- Ohshima Hospital of Ophthalmology, 11-8 Kamigofuku, Hakata-ku, Fukuoka 812-0036, Japan; Yamaguchi University, 1-1-1 Minami-kogushi, Ube City, Yamaguchi 755-8505, Japan.
| | - Makoto Inui
- Department of Pharmacology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-kogushi, Ube City, Yamaguchi 755-8505, Japan
| | - Motoyoshi Nomizu
- Laboratory of Clinical Biochemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
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Chen DK, Frizzi KE, Guernsey LS, Ladt K, Mizisin AP, Calcutt NA. Repeated monitoring of corneal nerves by confocal microscopy as an index of peripheral neuropathy in type-1 diabetic rodents and the effects of topical insulin. J Peripher Nerv Syst 2014; 18:306-15. [PMID: 24147903 DOI: 10.1111/jns5.12044] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 08/07/2013] [Accepted: 10/11/2013] [Indexed: 02/06/2023]
Abstract
We developed a reliable imaging and quantitative analysis method for in vivo corneal confocal microscopy (CCM) in rodents and used it to determine whether models of type 1 diabetes replicate the depletion of corneal nerves reported in diabetic patients. Quantification was reproducible between observers and stable across repeated time points in two rat strains. Longitudinal studies were performed in normal and streptozotocin (STZ)-diabetic rats, with innervation of plantar paw skin quantified using standard histological methods after 40 weeks of diabetes. Diabetic rats showed an initial increase, then a gradual reduction in occupancy of nerves in the sub-basal plexus so that values were significantly lower at week 40 (68 ± 6%) than age-matched controls (80 ± 2%). No significant loss of stromal or intra-epidermal nerves was detected. In a separate study, insulin was applied daily to the eye of control and STZ-diabetic mice and this treatment prevented depletion of nerves of the sub-basal plexus. Longitudinal studies are viable in rodents using CCM and depletion of distal corneal nerves precedes detectable loss of epidermal nerves in the foot, suggesting that diabetic neuropathy is not length dependent. Loss of insulin-derived neurotrophic support may contribute to the pathogenesis of corneal nerve depletion in type 1 diabetes.
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Affiliation(s)
- Debbie K Chen
- Department of Pathology, School of Medicine, University of California, San Diego, La Jolla, CA, USA
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Stem MS, Hussain M, Lentz SI, Raval N, Gardner TW, Pop-Busui R, Shtein RM. Differential reduction in corneal nerve fiber length in patients with type 1 or type 2 diabetes mellitus. J Diabetes Complications 2014; 28:658-61. [PMID: 25044236 PMCID: PMC4146399 DOI: 10.1016/j.jdiacomp.2014.06.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 06/06/2014] [Accepted: 06/11/2014] [Indexed: 02/06/2023]
Abstract
AIM To examine the relationship between corneal nerve fiber length (CNFL) and diabetic neuropathy (DN) status in patients with type 1 or type 2 diabetes mellitus (DM). METHODS In this cross-sectional study, we examined 25 diabetic patients without DN, 10 patients with mild DN, 8 patients with severe DN, and 9 controls without diabetes. DN status was assigned based on a combination of clinical symptoms, signs, and electrophysiological testing. Patients underwent corneal confocal microscopy (CCM) of the sub-basal nerve plexus. Post-hoc analysis of the CCM images was performed to quantify the average CNFL, and ANOVA was used to assess for differences in CNFL. RESULTS All 25 subjects without DN had type 1 DM, and subjects with DN had type 2 DM. Participants with severe DN had significantly lower CNFL (12.5±6.1mm/mm(2)) compared to controls (20.7±2.2mm/mm(2)) (p=0.009). However, lower CNFL was also found in participants with type 1 DM who did not have DN (15.1±4.7mm/mm(2)) relative to controls (p=0.033). CONCLUSIONS CCM of the sub-basal nerve plexus may be an indicator of early peripheral nerve degeneration in type 1 DM. Type of diabetes, in addition to degree of neuropathy, may influence the extent of corneal nerve damage.
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Affiliation(s)
- Maxwell S Stem
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School
| | - Munira Hussain
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School
| | - Stephen I Lentz
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Nilesh Raval
- University of Michigan Undergraduate Program, Ann Arbor, MI
| | - Thomas W Gardner
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School
| | - Rodica Pop-Busui
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Roni M Shtein
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School.
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The impact of type 1 diabetes mellitus on corneal epithelial nerve morphology and the corneal epithelium. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2662-70. [PMID: 25102563 DOI: 10.1016/j.ajpath.2014.06.016] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 05/14/2014] [Accepted: 06/17/2014] [Indexed: 12/23/2022]
Abstract
Diabetic corneal neuropathy can result in chronic, sight-threatening corneal pathology. Although the exact etiology is unknown, it is believed that a reduction in corneal sensitivity and loss of neurotrophic support contributes to corneal disease. Information regarding the relationship between nerve loss and effects on the corneal epithelium is limited. We investigated changes in the corneal epithelium and nerve morphology using three-dimensional imaging in vivo and in situ in a streptozotocin-induced diabetic mouse model. Streptozotocin-treated mice showed increased levels of serum glucose and growth retardation consistent with a severe diabetic state. A reduction in the length of the subbasal nerve plexus was evident after 6 weeks of disease. Loss of the subbasal nerve plexus was associated with corneal epithelial thinning and a reduction in basal epithelial cell density. In contrast, loss of the terminal epithelial nerves was associated with animal age. Importantly, this is the first rodent model of type 1 diabetes that shows characteristics of corneal epithelial thinning and a reduction in basal epithelial cell density, both previously have been documented in humans with diabetic corneal neuropathy. These findings indicate that in type 1 diabetes, nerve fiber damage is evident in the subbasal nerve plexus before terminal epithelial nerve loss and that neurotrophic support from both the subbasal nerve plexus and terminal epithelial nerves is essential for the maintenance of corneal epithelial homeostasis.
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Davidson EP, Coppey LJ, Kardon RH, Yorek MA. Differences and similarities in development of corneal nerve damage and peripheral neuropathy and in diet-induced obesity and type 2 diabetic rats. Invest Ophthalmol Vis Sci 2014; 55:1222-30. [PMID: 24519423 DOI: 10.1167/iovs.13-13794] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
PURPOSE Peripheral neuropathy has been shown to exist in prediabetic and diabetic patients and animal models. However, the development of peripheral neuropathy in prediabetes and posthyperglycemia is likely different. The purpose of this study was to examine the progression of peripheral neuropathy in diet-induced obese rats and high-fat-fed rats treated with a low dose of streptozotocin, a model for type 2 diabetes, using standard endpoints as well as corneal sensitivity and innervation. METHODS Diet-induced obese rats and high-fat/low-dose streptozotocin diabetic rats were used to examine standard peripheral neuropathy endpoints and innervation of the cornea and corneal epithelium using corneal and standard confocal microscopy, respectively, and corneal sensitivity using a Cochet-Bonnet esthesiometer at three different time points. RESULTS Obese rats and to a greater extent diabetic rats were insulin resistant. Obese and diabetic rats had developed sensory nerve deficits, but only diabetic rats had motor nerve dysfunction as determined by measuring nerve conduction velocity, thermal nociception, and intraepidermal nerve fiber density. In the cornea there was a decrease in corneal nerve fiber length, innervation of the corneal epithelium, and corneal sensitivity in both diet-induced obese and diabetic rats. CONCLUSIONS These studies demonstrate that changes in corneal nerve innervation and sensitivity occur in both obese and type 2 diabetic rat models that are consistent with development of peripheral neuropathy. Examination of corneal nerve changes may be valuable endpoints for exploring potential treatments for peripheral neuropathy in both prediabetes with insulin resistance and diabetes.
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Affiliation(s)
- Eric P Davidson
- Department of Internal Medicine, The University of Iowa, Iowa City, Iowa
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Lee-Kubli CA, Mixcoatl-Zecuatl T, Jolivalt CG, Calcutt NA. Animal models of diabetes-induced neuropathic pain. Curr Top Behav Neurosci 2014; 20:147-70. [PMID: 24510303 DOI: 10.1007/7854_2014_280] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Neuropathy will afflict over half of the approximately 350 million people worldwide who currently suffer from diabetes and around one-third of diabetic patients with neuropathy will suffer from painful symptoms that may be spontaneous or stimulus evoked. Diabetes can be induced in rats or mice by genetic, dietary, or chemical means, and there are a variety of well-characterized models of diabetic neuropathy that replicate either type 1 or type 2 diabetes. Diabetic rodents display aspects of sensorimotor dysfunction such as stimulus-evoked allodynia and hyperalgesia that are widely used to model painful neuropathy. This allows investigation of pathogenic mechanisms and development of potential therapeutic interventions that may alleviate established pain or prevent onset of pain.
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Saghizadeh M, Epifantseva I, Hemmati DM, Ghiam CA, Brunken WJ, Ljubimov AV. Enhanced wound healing, kinase and stem cell marker expression in diabetic organ-cultured human corneas upon MMP-10 and cathepsin F gene silencing. Invest Ophthalmol Vis Sci 2013; 54:8172-80. [PMID: 24255036 DOI: 10.1167/iovs.13-13233] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
PURPOSE Diabetic corneas overexpress proteinases including matrix metalloproteinase-10 (M10) and cathepsin F (CF). Our purpose was to assess if silencing M10 and CF in organ-cultured diabetic corneas using recombinant adenovirus (rAV)-driven small hairpin RNA (rAV-sh) would normalize slow wound healing, and diabetic and stem cell marker expression. METHODS Sixteen pairs of organ-cultured autopsy human diabetic corneas (four per group) were treated with rAV-sh. Proteinase genes were silenced either separately, together, or both, in combination (Combo) with rAV-driven c-met gene overexpression. Fellow control corneas received rAV-EGFP. Quantitative RT-PCR confirmed small hairpin RNA (shRNA) silencing effect. Ten days after transfection, 5-mm epithelial wounds were made with n-heptanol and healing time recorded. Diabetic, signaling, and putative stem cell markers were studied by immunofluorescence of corneal cryostat sections. RESULTS Proteinase silencing reduced epithelial wound healing time versus rAV-enhanced green fluorescent protein (EGFP) control (23% for rAV-shM10, 31% for rAV-shCF, and 36% for rAV-shM10 + rAV-shCF). Combo treatment was even more efficient (55% reduction). Staining patterns of diabetic markers (α₃β₁ integrin and nidogen-1), and of activated epidermal growth factor receptor and its signaling target activated Akt were normalized upon rAV-sh treatment. Combo treatment also restored normal staining for activated p38. All treatments, especially the combined ones, increased diabetes-altered staining for putative limbal stem cell markers, ΔNp63α, ABCG2, keratins 15 and 17, and laminin γ3 chain. CONCLUSIONS Small hairpin RNA silencing of proteinases overexpressed in diabetic corneas enhanced corneal epithelial and stem cell marker staining and accelerated wound healing. Combined therapy with c-met overexpression was even more efficient. Specific corneal gene therapy has a potential for treating diabetic keratopathy.
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Affiliation(s)
- Mehrnoosh Saghizadeh
- Eye Program, Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California
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Gong CY, Lu B, Hu QW, Ji LL. Streptozotocin induced diabetic retinopathy in rat and the expression of vascular endothelial growth factor and its receptor. Int J Ophthalmol 2013; 6:573-7. [PMID: 24195027 DOI: 10.3980/j.issn.2222-3959.2013.05.03] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 08/13/2013] [Indexed: 12/17/2022] Open
Abstract
AIM To establish the rat model of streptozotocin (STZ)-induced diabetic retinopathy (DR), which is the most common cause of visual loss and blindness in patients with diabetes, and observe the gene expression of vascular endothelial growth factor (VEGF) and its receptors during the development of DR. METHODS A rat model of diabetes was established by intraperitoneal injection of STZ. The diabetic rats were housed for 2, 3 and 4 months after the development of diabetes. Retinal histopathological observation was performed. The retinal vessels were observed by immunofluorescence staining by CD31. The mRNA expression of VEGF, VEGF receptor 1 and 2 (VEGFR1/2) in rat retina was detected by reverse transcription-polymerase chain reaction (RT-PCR) analysis. RESULTS Retinal histopathological observation showed the morphological changes of inner nuclear layer (INL) and outer nuclear layer (ONL) at any time-point, and also demonstrated the increased new vessels at both 3, 4 months after the development of diabetes. The CD31 staining results showed that the number of vessels was increased in the retinas of diabetic rats at both 3 and 4 months after the development of diabetes. As compared to the normal rats, the mRNA expression of VEGF was increased in retinas of diabetic rats at 3 months after the development of diabetes, while VEGFR1 and VEGFR2 mRNA expression was increased at 2, 3 and 4 months after the development of diabetes. CONCLUSION Taken together, our results demonstrated that DR was occurred at 3 months after the development of diabetes, and the mRNA expression of VEGF, VEGFR1 and VEGFR2 were increased in the process of DR. The present study further evidenced the involvement of VEGF and its receptors in the process of DR.
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Affiliation(s)
- Chen-Yuan Gong
- The MOE Key Laboratory for Standardization of Chinese Medicines and The Shanghai Key Laboratory for Compound Chinese medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
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Tavakoli M, Petropoulos IN, Malik RA. Corneal confocal microscopy to assess diabetic neuropathy: an eye on the foot. J Diabetes Sci Technol 2013; 7:1179-89. [PMID: 24124944 PMCID: PMC3876361 DOI: 10.1177/193229681300700509] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Accurate detection and quantification of human diabetic peripheral neuropathy are important to define at-risk patients, anticipate deterioration, and assess new therapies. Easily performed clinical techniques such as neuro-logical examination, assessment of vibration perception or insensitivity to the 10 g monofilament only assess advanced neuropathy, i.e., the at-risk foot. Techniques that assess early neuropathy include neurophysiology (which assesses only large fibers) and quantitative sensory testing (which assesses small fibers), but they can be highly subjective while more objective techniques, such as skin biopsy for intra-epidermal nerve fiber density quantification, are invasive and not widely available. The emerging ophthalmic technique of corneal confocal microscopy allows quantification of corneal nerve morphology and enables clinicians to diagnose peripheral neuropathy in diabetes patients, quantify its severity, and potentially assess therapeutic benefit. The present review provides a detailed critique of the rationale, a practical approach to capture images, and a basis for analyzing and interpreting the images. We also critically evaluate the diagnostic ability of this new noninvasive ophthalmic test to diagnose diabetic and other peripheral neuropathies.
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Affiliation(s)
- Mitra Tavakoli
- Center for Endocrinology and Diabetes, Institute of Human Development, University of Manchester and Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Center, Manchester, United Kingdom
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Abstract
Corneal confocal microscopy (CCM) is a noninvasive method for the study of human cornea in vivo. It has increasingly been used to assess the morphology of the sub-basal corneal nerve plexus. CCM has good reproducibility and may contribute to the early diagnosis of diabetic polyneuropathy. It may also be useful to document favorable changes in nerve fiber structure early after therapeutic intervention. Corneal nerve pathology is more pronounced in patients with diabetic polyneuropathy and is associated with its clinical severity. The sensitivity and specificity of CCM for the diagnosis of polyneuropathy is moderate to high. CCM now merits further use in large longitudinal studies to provide more information on the natural history of diabetic neuropathy and effects of treatment. Moreover, there is a need for a larger normative database. Finally, technical progress is expected to enable visualization of larger corneal areas and improve nerve fiber quantification, increasing diagnostic accuracy.
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Affiliation(s)
- N Papanas
- Institute for Clinical Diabetology, German Diabetes Center at the Heinrich Heine University, Auf'm Hennekamp 65, 40225, Düsseldorf, Germany
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