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Attia MA, Soliman N, Eladl MA, Bilasy SE, El-Abaseri TB, Ali HS, Abbas F, Ibrahim D, Osman NMS, Hashish AA, Alshahrani A, Mohamed AS, Zaitone SA. Topiramate affords neuroprotection in diabetic neuropathy model via downregulating spinal GFAP/inflammatory burden and improving neurofilament production. Toxicol Mech Methods 2023; 33:563-577. [PMID: 36978280 DOI: 10.1080/15376516.2023.2196687] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/19/2023] [Accepted: 02/21/2023] [Indexed: 03/30/2023]
Abstract
The current study aimed to test the neuroprotective action of topiramate in mouse peripheral diabetic neuropathy (DN) and explored some mechanisms underlying this action. Mice were assigned as vehicle group, DN group, DN + topiramate 10-mg/kg and DN + topiramate 30-mg/kg. Mice were tested for allodynia and hyperalgesia and then spinal cord and sciatic nerves specimens were examined microscopically and neurofilament heavy chain (NEFH) immunostaining was performed. Results indicated that DN mice had lower the hotplate latency time (0.46-fold of latency to licking) and lower von-Frey test pain threshold (0.6-fold of filament size) while treatment with topiramate increased these values significantly. Sciatic nerves from DN control mice showed axonal degeneration while spinal cords showed elevated GFAP (5.6-fold) and inflammatory cytokines (∼3- to 4-fold) but lower plasticity as indicated by GAP-43 (0.25-fold). Topiramate produced neuroprotection and suppressed spinal cord GFAP/inflammation but enhanced GAP-43. This study reinforces topiramate as neuroprotection and explained some mechanisms included in alleviating neuropathy.
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Affiliation(s)
- Mohammed A Attia
- Department of Pharmacology, College of Medicine, AlMaarefa University, Riyadh, Saudi Arabia
- Department of Clinical Pharmacology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Nema Soliman
- Department of Histology and Cell Biology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
- Center of Excellence of Molecular and Cellular Medicine, Suez Canal University, Ismailia, Egypt
| | - Mohamed Ahmed Eladl
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Shymaa E Bilasy
- Department of Biochemistry, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt
- College of Dental Medicine, California Northstate University, Elk Grove, CA, USA
| | - Taghrid B El-Abaseri
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Howaida S Ali
- Department of Pharmacology, Faculty of Medicine, Assiut University, Assiut, Egypt
- Department of Pharmacology, Faculty of Medicine, University of Tabuk, Tabuk, Saudi Arabia
| | - Faten Abbas
- Physiology department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Dalia Ibrahim
- Physiology department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Noura M S Osman
- Department of Human Anatomy and Embryology, Faculty of Medicine, Port Said University, Port Said, Egypt
| | - Abdullah A Hashish
- Basic Medical Sciences Department, College of Medicine, University of Bisha, Bisha, Saudi Arabia
- Department of Clinical Pathology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Asma Alshahrani
- Department of Clinical Pharmacy, College of Pharmacy, King Khalid University, Abha, KSA
| | - Abir S Mohamed
- Faculty of Public Health and Tropical Medicine, Jazan University, Jazan, Saudi Arabia
| | - Sawsan A Zaitone
- Deparment of Pharmacology and Toxicology, Faculty of Pharmacy, University of Tabuk, Tabuk, Saudi Arabia
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt
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Baum P, Toyka KV, Blüher M, Kosacka J, Nowicki M. Inflammatory Mechanisms in the Pathophysiology of Diabetic Peripheral Neuropathy (DN)-New Aspects. Int J Mol Sci 2021; 22:10835. [PMID: 34639176 PMCID: PMC8509236 DOI: 10.3390/ijms221910835] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/30/2021] [Accepted: 10/04/2021] [Indexed: 12/15/2022] Open
Abstract
The pathogenesis of diabetic neuropathy is complex, and various pathogenic pathways have been proposed. A better understanding of the pathophysiology is warranted for developing novel therapeutic strategies. Here, we summarize recent evidence from experiments using animal models of type 1 and type 2 diabetes showing that low-grade intraneural inflammation is a facet of diabetic neuropathy. Our experimental data suggest that these mild inflammatory processes are a likely common terminal pathway in diabetic neuropathy associated with the degeneration of intraepidermal nerve fibers. In contrast to earlier reports claiming toxic effects of high-iron content, we found the opposite, i.e., nutritional iron deficiency caused low-grade inflammation and fiber degeneration while in normal or high non-heme iron nutrition no or only extremely mild inflammatory signs were identified in nerve tissue. Obesity and dyslipidemia also appear to trigger mild inflammation of peripheral nerves, associated with neuropathy even in the absence of overt diabetes mellitus. Our finding may be the experimental analog of recent observations identifying systemic proinflammatory activity in human sensorimotor diabetic neuropathy. In a rat model of type 1 diabetes, a mild neuropathy with inflammatory components could be induced by insulin treatment causing an abrupt reduction in HbA1c. This is in line with observations in patients with severe diabetes developing a small fiber neuropathy upon treatment-induced rapid HbA1c reduction. If the inflammatory pathogenesis could be further substantiated by data from human tissues and intervention studies, anti-inflammatory compounds with different modes of action may become candidates for the treatment or prevention of diabetic neuropathy.
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Affiliation(s)
- Petra Baum
- Department of Neurology, University of Leipzig, Liebigstraße 20, D-04103 Leipzig, Germany;
| | - Klaus V. Toyka
- Department of Neurology, University of Würzburg, Josef-Schneider-Str. 11, D-97080 Würzburg, Germany;
| | - Matthias Blüher
- Department of Medicine, University of Leipzig, Liebigstraße 20, D-04103 Leipzig, Germany;
| | - Joanna Kosacka
- Department of Visceral, Transplant, Thoracic and Vascular Surgery, University of Leipzig, D-04103 Leipzig, Germany;
| | - Marcin Nowicki
- Institute of Anatomy, University of Leipzig, Liebigstraße 13, D-04103 Leipzig, Germany
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3
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Hagen KM, Ousman SS. Aging and the immune response in diabetic peripheral neuropathy. J Neuroimmunol 2021; 355:577574. [PMID: 33894676 DOI: 10.1016/j.jneuroim.2021.577574] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 04/09/2021] [Accepted: 04/10/2021] [Indexed: 12/27/2022]
Abstract
A large proportion of older individuals with diabetes go on to develop diabetic peripheral neuropathy (DPN). DPN is associated with an increase in inflammatory cells within the peripheral nerve, activation of nuclear factor kappa-light-chain-enhancer of activated B cells and receptors for advanced glycation end products/advanced glycation end products pathways, aberrant cytokine expression, oxidative stress, ischemia, as well as pro-inflammatory changes in the bone marrow; all processes that may be exacerbated with age. We review the immunological features of DPN and discuss whether age-related changes in relevant immunological areas may contribute to age being a risk factor for DPN.
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Affiliation(s)
- Kathleen M Hagen
- Department of Neuroscience, Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Shalina S Ousman
- Departments of Clinical Neurosciences and Cell Biology and Anatomy, Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada.
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4
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Abstract
Neuropathy is a common complication of long-term diabetes that impairs quality of life by producing pain, sensory loss and limb amputation. The presence of neuropathy in both insulin-deficient (type 1) and insulin resistant (type 2) diabetes along with the slowing of progression of neuropathy by improved glycemic control in type 1 diabetes has caused the majority of preclinical and clinical investigations to focus on hyperglycemia as the initiating pathogenic lesion. Studies in animal models of diabetes have identified multiple plausible mechanisms of glucotoxicity to the nervous system including post-translational modification of proteins by glucose and increased glucose metabolism by aldose reductase, glycolysis and other catabolic pathways. However, it is becoming increasingly apparent that factors not necessarily downstream of hyperglycemia can also contribute to the incidence, progression and severity of neuropathy and neuropathic pain. For example, peripheral nerve contains insulin receptors that transduce the neurotrophic and neurosupportive properties of insulin, independent of systemic glucose regulation, while the detection of neuropathy and neuropathic pain in patients with metabolic syndrome and failure of improved glycemic control to protect against neuropathy in cohorts of type 2 diabetic patients has placed a focus on the pathogenic role of dyslipidemia. This review provides an overview of current understanding of potential initiating lesions for diabetic neuropathy and the multiple downstream mechanisms identified in cell and animal models of diabetes that may contribute to the pathogenesis of diabetic neuropathy and neuropathic pain.
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5
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Kassab S, Begley P, Church SJ, Rotariu SM, Chevalier-Riffard C, Dowsey AW, Phillips AM, Zeef LAH, Grayson B, Neill JC, Cooper GJS, Unwin RD, Gardiner NJ. Cognitive dysfunction in diabetic rats is prevented by pyridoxamine treatment. A multidisciplinary investigation. Mol Metab 2019; 28:107-119. [PMID: 31451429 PMCID: PMC6822151 DOI: 10.1016/j.molmet.2019.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/24/2019] [Accepted: 08/01/2019] [Indexed: 01/21/2023] Open
Abstract
OBJECTIVE The impact of diabetes mellitus on the central nervous system is less widely studied than in the peripheral nervous system, but there is increasing evidence that it elevates the risk of developing cognitive deficits. The aim of this study was to characterize the impact of experimental diabetes on the proteome and metabolome of the hippocampus. We tested the hypothesis that the vitamin B6 isoform pyridoxamine is protective against functional and molecular changes in diabetes. METHODS We tested recognition memory using the novel object recognition (NOR) test in streptozotocin (STZ)-induced diabetic, age-matched control, and pyridoxamine- or insulin-treated diabetic male Wistar rats. Comprehensive untargeted metabolomic and proteomic analyses, using gas chromatography-mass spectrometry and iTRAQ-enabled protein quantitation respectively, were utilized to characterize the molecular changes in the hippocampus in diabetes. RESULTS We demonstrated diabetes-specific, long-term (but not short-term) recognition memory impairment and that this deficit was prevented by insulin or pyridoxamine treatment. Metabolomic analysis showed diabetes-associated changes in 13/82 identified metabolites including polyol pathway intermediates glucose (9.2-fold), fructose (4.9-fold) and sorbitol (5.2-fold). We identified and quantified 4807 hippocampal proteins; 806 were significantly altered in diabetes. Pathway analysis revealed significant alterations in cytoskeletal components associated with synaptic plasticity, glutamatergic signaling, oxidative stress, DNA damage and FXR/RXR activation pathways in the diabetic rat hippocampus. CONCLUSIONS Our data indicate a protective effect of pyridoxamine against diabetes-induced cognitive deficits, and our comprehensive 'omics datasets provide insight into the pathogenesis of cognitive dysfunction enabling development of further mechanistic and therapeutic studies.
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Affiliation(s)
- Sarah Kassab
- Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Paul Begley
- Faculty of Biology, Medicine and Health, University of Manchester, UK
| | | | | | | | - Andrew W Dowsey
- Department of Population Health Sciences and Bristol Veterinary School, Faculty of Health Sciences, University of Bristol, Bristol, BS8 2BN, UK
| | - Alexander M Phillips
- Department of Electrical Engineering and Electronics, University of Liverpool, UK
| | - Leo A H Zeef
- Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Ben Grayson
- Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Joanna C Neill
- Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Garth J S Cooper
- Faculty of Biology, Medicine and Health, University of Manchester, UK; School of Biological Sciences, University of Auckland, New Zealand
| | - Richard D Unwin
- Faculty of Biology, Medicine and Health, University of Manchester, UK
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Lós DB, Oliveira WHD, Duarte-Silva E, Sougey WWD, Freitas EDSRD, de Oliveira AGV, Braga CF, França MERD, Araújo SMDR, Rodrigues GB, Rocha SWS, Peixoto CA, Moraes SRAD. Preventive role of metformin on peripheral neuropathy induced by diabetes. Int Immunopharmacol 2019; 74:105672. [DOI: 10.1016/j.intimp.2019.05.057] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/21/2019] [Accepted: 05/28/2019] [Indexed: 12/23/2022]
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Makino E, Nakamura N, Miyabe M, Ito M, Kanada S, Hata M, Saiki T, Sango K, Kamiya H, Nakamura J, Miyazawa K, Goto S, Matsubara T, Naruse K. Conditioned media from dental pulp stem cells improved diabetic polyneuropathy through anti-inflammatory, neuroprotective and angiogenic actions: Cell-free regenerative medicine for diabetic polyneuropathy. J Diabetes Investig 2019; 10:1199-1208. [PMID: 30892819 PMCID: PMC6717901 DOI: 10.1111/jdi.13045] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/19/2019] [Accepted: 03/10/2019] [Indexed: 12/11/2022] Open
Abstract
AIMS/INTRODUCTION Dental pulp stem cells (DPSCs) can be easily obtained from teeth for general orthodontic reasons. We have previously reported the therapeutic effects of DPSC transplantation for diabetic polyneuropathy. As abundant secretomes from DPSCs are considered to play a central role in the improvement of diabetic polyneuropathy, we investigated whether direct injection of DPSC-conditioned media (DPSC-CM) into hindlimb skeletal muscles ameliorates diabetic polyneuropathy in diabetic rats. MATERIALS AND METHODS DPSCs were isolated from the dental pulp of Sprague-Dawley rats. Eight weeks after the induction of diabetes, DPSC-CM was injected into the unilateral hindlimb skeletal muscles in both normal and diabetic rats. The effects of DPSC-CM on diabetic polyneuropathy were assessed 4 weeks after DPSC-CM injection. To confirm the angiogenic effect of DPSC-CM, the effect of DPSC-CM on cultured human umbilical vascular endothelial cell proliferation was investigated. RESULTS The administration of DPSC-CM into the hindlimb skeletal muscles significantly ameliorated sciatic motor/sensory nerve conduction velocity, sciatic nerve blood flow and intraepidermal nerve fiber density in the footpads of diabetic rats. We also showed that DPSC-CM injection significantly increased the capillary density of the skeletal muscles, and suppressed pro-inflammatory reactions in the sciatic nerves of diabetic rats. Furthermore, an in vitro study showed that DPSC-CM significantly increased the proliferation of umbilical vascular endothelial cells. CONCLUSIONS We showed that DPSC-CM injection into hindlimb skeletal muscles has a therapeutic effect on diabetic polyneuropathy through neuroprotective, angiogenic and anti-inflammatory actions. DPSC-CM could be a novel cell-free regenerative medicine treatment for diabetic polyneuropathy.
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Affiliation(s)
- Eriko Makino
- Department of OrthodonticsSchool of DentistryAichi Gakuin UniversityNagoyaJapan
| | - Nobuhisa Nakamura
- Department of Internal MedicineSchool of DentistryAichi Gakuin UniversityNagoyaJapan
| | - Megumi Miyabe
- Department of Internal MedicineSchool of DentistryAichi Gakuin UniversityNagoyaJapan
| | - Mizuho Ito
- Department of Internal MedicineSchool of DentistryAichi Gakuin UniversityNagoyaJapan
| | - Saki Kanada
- Department of OrthodonticsSchool of DentistryAichi Gakuin UniversityNagoyaJapan
| | - Masaki Hata
- Department of Removable ProsthodonticsSchool of DentistryAichi Gakuin UniversityNagoyaJapan
| | - Tomokazu Saiki
- Department of PharmacyDental HospitalAichi Gakuin UniversityNagoyaJapan
| | - Kazunori Sango
- Laboratory of Peripheral Nerve PathophysiologyTokyo Metropolitan Institute of Medical ScienceTokyoJapan
| | - Hideki Kamiya
- Division of DiabetesDepartment of Internal MedicineAichi Medical UniversityNagakuteJapan
| | - Jiro Nakamura
- Division of DiabetesDepartment of Internal MedicineAichi Medical UniversityNagakuteJapan
| | - Ken Miyazawa
- Department of OrthodonticsSchool of DentistryAichi Gakuin UniversityNagoyaJapan
| | - Shigemi Goto
- Department of OrthodonticsSchool of DentistryAichi Gakuin UniversityNagoyaJapan
| | - Tatsuaki Matsubara
- Department of Internal MedicineSchool of DentistryAichi Gakuin UniversityNagoyaJapan
| | - Keiko Naruse
- Department of Internal MedicineSchool of DentistryAichi Gakuin UniversityNagoyaJapan
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8
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Gonçalves NP, Vægter CB, Pallesen LT. Peripheral Glial Cells in the Development of Diabetic Neuropathy. Front Neurol 2018; 9:268. [PMID: 29770116 PMCID: PMC5940740 DOI: 10.3389/fneur.2018.00268] [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] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 04/06/2018] [Indexed: 12/15/2022] Open
Abstract
The global prevalence of diabetes is rapidly increasing, affecting more than half a billion individuals within the next few years. As diabetes negatively affects several physiological systems, this dramatic increase represents not only impaired quality of life on the individual level but also a huge socioeconomic challenge. One of the physiological consequences affecting up to half of diabetic patients is the progressive deterioration of the peripheral nervous system, resulting in spontaneous pain and eventually loss of sensory function, motor weakness, and organ dysfunctions. Despite intense research on the consequences of hyperglycemia on nerve functions, the biological mechanisms underlying diabetic neuropathy are still largely unknown, and treatment options lacking. Research has mainly focused directly on the neuronal component, presumably from the perspective that this is the functional signal-transmitting unit of the nerve. However, it is noteworthy that each single peripheral sensory neuron is intimately associated with numerous glial cells; the neuronal soma is completely enclosed by satellite glial cells and the length of the longest axons covered by at least 1,000 Schwann cells. The glial cells are vital for the neuron, but very little is still known about these cells in general and especially how they respond to diabetes in terms of altered neuronal support. We will discuss current knowledge of peripheral glial cells and argue that increased research in these cells is imperative for a better understanding of the mechanisms underlying diabetic neuropathy.
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Affiliation(s)
- Nádia Pereira Gonçalves
- Department of Biomedicine, Nordic-EMBL Partnership for Molecular Medicine, Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, Aarhus, Denmark.,The International Diabetic Neuropathy Consortium (IDNC), Aarhus University, Aarhus, Denmark
| | - Christian Bjerggaard Vægter
- Department of Biomedicine, Nordic-EMBL Partnership for Molecular Medicine, Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, Aarhus, Denmark.,The International Diabetic Neuropathy Consortium (IDNC), Aarhus University, Aarhus, Denmark
| | - Lone Tjener Pallesen
- Department of Biomedicine, Nordic-EMBL Partnership for Molecular Medicine, Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, Aarhus, Denmark
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9
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Gonçalves NP, Vægter CB, Andersen H, Østergaard L, Calcutt NA, Jensen TS. Schwann cell interactions with axons and microvessels in diabetic neuropathy. Nat Rev Neurol 2017; 13:135-147. [PMID: 28134254 DOI: 10.1038/nrneurol.2016.201] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The prevalence of diabetes worldwide is at pandemic levels, with the number of patients increasing by 5% annually. The most common complication of diabetes is peripheral neuropathy, which has a prevalence as high as 50% and is characterized by damage to neurons, Schwann cells and blood vessels within the nerve. The pathogenic mechanisms of diabetic neuropathy remain poorly understood, impeding the development of targeted therapies to treat nerve degeneration and its most disruptive consequences of sensory loss and neuropathic pain. Involvement of Schwann cells has long been proposed, and new research techniques are beginning to unravel a complex interplay between these cells, axons and microvessels that is compromised during the development of diabetic neuropathy. In this Review, we discuss the evolving concept of Schwannopathy as an integral factor in the pathogenesis of diabetic neuropathy, and how disruption of the interactions between Schwann cells, axons and microvessels contribute to the disease.
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Affiliation(s)
- Nádia P Gonçalves
- The International Diabetic Neuropathy Consortium (IDNC), Aarhus University, Nørrebrogade, 8000 Aarhus C, Denmark
| | - Christian B Vægter
- Danish Research Institute of Translational Neuroscience DANDRITE, Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Ole Worms Alle 3, 8000 Aarhus C, Denmark
| | - Henning Andersen
- Department of Neurology, Danish Pain Research Center and IDNC, Aarhus University Hospital, Nørrebrogade, 8000 Aarhus C, Denmark
| | - Leif Østergaard
- Department of Neuroradiology and Center for Functionally Integrative Neuroscience, Aarhus University Hospital, Nørrebrogade, 8000 Aarhus C, Denmark
| | - Nigel A Calcutt
- Department of Pathology, University of California San Diego, Gilman Drive, La Jolla, California 92093, USA
| | - Troels S Jensen
- Department of Neurology, Danish Pain Research Center and IDNC, Aarhus University Hospital, Nørrebrogade, 8000 Aarhus C, Denmark
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Nukada H, Baba M, Ogasawara S, McMorran D, Yagihashi S. Neuropathy in the spontaneously hypertensive rat: An electrophysiological and histological study. Muscle Nerve 2016; 54:756-62. [PMID: 26970072 DOI: 10.1002/mus.25098] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 02/24/2016] [Accepted: 03/03/2016] [Indexed: 02/04/2023]
Abstract
INTRODUCTION Hypertension is identified as a risk factor for development of polyneuropathy. In this study we examined nerve conduction and morphological alteration of peripheral nerves in spontaneously hypertensive rats (SHR). METHODS Motor nerve conduction velocity (MNCV) in the sciatic-tibial nerve and sensory nerve conduction velocity (SNCV) in the sural nerve were measured. Pathological investigations included spinal cord, dorsal root ganglion, and hindlimb nerves in SHR and Wistar-Kyoto rats (WKY) aged 4-64 weeks. RESULTS Blood pressure was significantly higher in SHR than WKY animals at 4 weeks and elevated further with aging. MNCV and SNCV were significantly slower in SHR compared with WKY after age 24 weeks. Prominent morphological changes in SHR nerves included axonal atrophy and myelin splitting. SHR also had endoneurial microangiopathy with reduplication of basement membrane. CONCLUSIONS SHR showed slowed nerve conduction velocity and pathological abnormalities of hindlimb nerves. Sustained severe hypertension may cause axonal atrophy and endoneurial microangiopathy. Muscle Nerve 54: 756-762, 2016.
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Affiliation(s)
- Hitoshi Nukada
- The Nukada Institute for Medical & Biological Research, 5-18 Inage-machi, Inage-ku, Chiba, 263-0035, Japan. .,Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
| | - Masayuki Baba
- Department of Neurology, Aomori Prefectural Central Hospital, Aomori, Japan
| | - Saori Ogasawara
- Department of Pathology and Molecular Medicine, Hirosaki University, Hirosaki, Japan
| | - Denise McMorran
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Soroku Yagihashi
- Department of Pathology and Molecular Medicine, Hirosaki University, Hirosaki, Japan
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Jha MK, Lee IK, Suk K. Metabolic reprogramming by the pyruvate dehydrogenase kinase-lactic acid axis: Linking metabolism and diverse neuropathophysiologies. Neurosci Biobehav Rev 2016; 68:1-19. [PMID: 27179453 DOI: 10.1016/j.neubiorev.2016.05.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/11/2016] [Accepted: 05/09/2016] [Indexed: 12/12/2022]
Abstract
Emerging evidence indicates that there is a complex interplay between metabolism and chronic disorders in the nervous system. In particular, the pyruvate dehydrogenase (PDH) kinase (PDK)-lactic acid axis is a critical link that connects metabolic reprogramming and the pathophysiology of neurological disorders. PDKs, via regulation of PDH complex activity, orchestrate the conversion of pyruvate either aerobically to acetyl-CoA, or anaerobically to lactate. The kinases are also involved in neurometabolic dysregulation under pathological conditions. Lactate, an energy substrate for neurons, is also a recently acknowledged signaling molecule involved in neuronal plasticity, neuron-glia interactions, neuroimmune communication, and nociception. More recently, the PDK-lactic acid axis has been recognized to modulate neuronal and glial phenotypes and activities, contributing to the pathophysiologies of diverse neurological disorders. This review covers the recent advances that implicate the PDK-lactic acid axis as a novel linker of metabolism and diverse neuropathophysiologies. We finally explore the possibilities of employing the PDK-lactic acid axis and its downstream mediators as putative future therapeutic strategies aimed at prevention or treatment of neurological disorders.
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Affiliation(s)
- Mithilesh Kumar Jha
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 PLUS KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea; Department of Neurology, Division of Neuromuscular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - In-Kyu Lee
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Kyoungho Suk
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 PLUS KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea.
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12
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Yagihashi S. Glucotoxic Mechanisms and Related Therapeutic Approaches. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 127:121-49. [PMID: 27133148 DOI: 10.1016/bs.irn.2016.03.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neuropathy is the earliest and commonest complication of diabetes. With increasing duration of diabetes, frequency and severity of neuropathy are worsened. Long-term hyperglycemia is therefore implicated in the development of this disorder. Nerve tissues require glucose energy to function and survive. Upon excessive glucose entry into the peripheral nerve, the glycolytic pathway and collateral glucose-utilizing pathways are overactivated and initiate adverse effects on nerve tissues. During hyperglycemia, flux through the polyol pathway, formation of advanced glycation end-products, production of free radicals, flux into the glucosamine pathway, and protein kinase C activity are all enhanced to negatively influence nerve function and structure. Suppression of these aberrant metabolic pathways has succeeded in prevention and inhibition of the development of neuropathy in animal models with diabetes. Satisfactory results were not attained, however, in patients with diabetes and further clinical trials are required. In this review, the author summarizes the hitherto proposed theories on the pathogenesis of diabetic neuropathy related to glucose metabolism and future prospects for the effective treatment of neuropathy.
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Affiliation(s)
- S Yagihashi
- Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
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13
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Rahman MH, Jha MK, Kim JH, Nam Y, Lee MG, Go Y, Harris RA, Park DH, Kook H, Lee IK, Suk K. Pyruvate Dehydrogenase Kinase-mediated Glycolytic Metabolic Shift in the Dorsal Root Ganglion Drives Painful Diabetic Neuropathy. J Biol Chem 2016; 291:6011-6025. [PMID: 26769971 DOI: 10.1074/jbc.m115.699215] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Indexed: 01/15/2023] Open
Abstract
The dorsal root ganglion (DRG) is a highly vulnerable site in diabetic neuropathy. Under diabetic conditions, the DRG is subjected to tissue ischemia or lower ambient oxygen tension that leads to aberrant metabolic functions. Metabolic dysfunctions have been documented to play a crucial role in the pathogenesis of diverse pain hypersensitivities. However, the contribution of diabetes-induced metabolic dysfunctions in the DRG to the pathogenesis of painful diabetic neuropathy remains ill-explored. In this study, we report that pyruvate dehydrogenase kinases (PDK2 and PDK4), key regulatory enzymes in glucose metabolism, mediate glycolytic metabolic shift in the DRG leading to painful diabetic neuropathy. Streptozotocin-induced diabetes substantially enhanced the expression and activity of the PDKs in the DRG, and the genetic ablation of Pdk2 and Pdk4 attenuated the hyperglycemia-induced pain hypersensitivity. Mechanistically, Pdk2/4 deficiency inhibited the diabetes-induced lactate surge, expression of pain-related ion channels, activation of satellite glial cells, and infiltration of macrophages in the DRG, in addition to reducing central sensitization and neuroinflammation hallmarks in the spinal cord, which probably accounts for the attenuated pain hypersensitivity. Pdk2/4-deficient mice were partly resistant to the diabetes-induced loss of peripheral nerve structure and function. Furthermore, in the experiments using DRG neuron cultures, lactic acid treatment enhanced the expression of the ion channels and compromised cell viability. Finally, the pharmacological inhibition of DRG PDKs or lactic acid production substantially attenuated diabetes-induced pain hypersensitivity. Taken together, PDK2/4 induction and the subsequent lactate surge induce the metabolic shift in the diabetic DRG, thereby contributing to the pathogenesis of painful diabetic neuropathy.
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Affiliation(s)
- Md Habibur Rahman
- From the Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program
| | - Mithilesh Kumar Jha
- From the Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program
| | - Jong-Heon Kim
- From the Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program
| | - Youngpyo Nam
- From the Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program
| | - Maan Gee Lee
- From the Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program
| | - Younghoon Go
- the Department of Internal Medicine, Division of Endocrinology and Metabolism, and
| | - Robert A Harris
- the Roudebush Veterans Affairs Medical Center and the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, and
| | - Dong Ho Park
- the Department of Ophthalmology, Kyungpook National University School of Medicine, Daegu 41944, Republic of Korea
| | - Hyun Kook
- the Department of Pharmacology, Chonnam National University Medical School, Gwangju 501-746, Republic of Korea
| | - In-Kyu Lee
- the Department of Internal Medicine, Division of Endocrinology and Metabolism, and
| | - Kyoungho Suk
- From the Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program,.
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14
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Ma J, Pan P, Anyika M, Blagg BSJ, Dobrowsky RT. Modulating Molecular Chaperones Improves Mitochondrial Bioenergetics and Decreases the Inflammatory Transcriptome in Diabetic Sensory Neurons. ACS Chem Neurosci 2015; 6:1637-48. [PMID: 26161583 DOI: 10.1021/acschemneuro.5b00165] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We have previously demonstrated that modulating molecular chaperones with KU-32, a novobiocin derivative, ameliorates physiologic and bioenergetic deficits of diabetic peripheral neuropathy (DPN). Replacing the coumarin core of KU-32 with a meta-fluorinated biphenyl ring system created KU-596, a novobiocin analogue (novologue) that showed neuroprotective activity in a cell-based assay. The current study sought to determine whether KU-596 offers similar therapeutic potential for treating DPN. Administration of 2-20 mg/kg of KU-596 improved diabetes induced hypoalgesia and sensory neuron bioenergetic deficits in a dose-dependent manner. However, the drug could not improve these neuropathic deficits in diabetic heat shock protein 70 knockout (Hsp70 KO) mice. To gain further insight into the mechanisms by which KU-596 improved DPN, we performed transcriptomic analysis of sensory neuron RNA obtained from diabetic wild-type and Hsp70 KO mice using RNA sequencing. Bioinformatic analysis of the differentially expressed genes indicated that diabetes strongly increased inflammatory pathways and that KU-596 therapy effectively reversed these increases independent of Hsp70. In contrast, the effects of KU-596 on decreasing the expression of genes regulating the production of reactive oxygen species were more Hsp70-dependent. These data indicate that modulation of molecular chaperones by novologue therapy offers an effective approach toward correcting nerve dysfunction in DPN but that normalization of inflammatory pathways alone by novologue therapy seems to be insufficient to reverse sensory deficits associated with insensate DPN.
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Affiliation(s)
- Jiacheng Ma
- Department of Pharmacology and Toxicology and ‡̂Department
of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas 66045, United States
| | - Pan Pan
- Department of Pharmacology and Toxicology and ‡̂Department
of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas 66045, United States
| | - Mercy Anyika
- Department of Pharmacology and Toxicology and ‡̂Department
of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas 66045, United States
| | - Brian S. J. Blagg
- Department of Pharmacology and Toxicology and ‡̂Department
of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas 66045, United States
| | - Rick T. Dobrowsky
- Department of Pharmacology and Toxicology and ‡̂Department
of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas 66045, United States
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15
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Wu S, Cao X, He R, Xiong K. Detrimental impact of hyperlipidemia on the peripheral nervous system: A novel target of medical epidemiological and fundamental research study. Neural Regen Res 2015; 7:392-9. [PMID: 25774180 PMCID: PMC4350124 DOI: 10.3969/j.issn.1673-5374.2012.05.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 12/14/2011] [Indexed: 01/07/2023] Open
Abstract
Recently, epidemiological studies on the etiology of peripheral neuropathies have revealed that hyperlipidemia is a novel risk factor. Plasma lipid levels were confirmed to be associated with the incidence of many peripheral neuropathies including axonal distal polyneuropathy, vision and hearing loss, motor nerve system lesions and sympathetic nerve system dysfunction. Moreover, different lipid components such as cholesterol, triacylglycerols and lipoprotein are involved in the pathogenesis of these neuropathies. This review aimed to discuss the effect of hyperlipidemia on the peripheral nervous system and its association with peripheral neuropathies. Furthermore, a detailed discussion focusing on the explicit mechanisms related to hyperlipidemia-induced peripheral neuropathies is presented here. These mechanisms, including intracellular oxidative stress, inflammatory lesions, ischemia and dysregulation of local lipid metabolism, share pathways and interact mutually. In addition, we examined current information on clinical trials to prevent and treat peripheral neuropathies caused by hyperlipidemia, with a predictive discussion regarding the orientation of future investigations.
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Affiliation(s)
- Song Wu
- Department of Orthopedics, Third Xiangya Hospital of Central South University, Changsha 410013, Hunan Province, China
| | - Xu Cao
- Clinical Medicine Eight-year Program, 01 Class, 07 Grade, Central South University, Changsha 410013, Hunan Province, China
| | - Rongzhen He
- Department of Orthopedics, Third Xiangya Hospital of Central South University, Changsha 410013, Hunan Province, China
| | - Kun Xiong
- Department of Anatomy and Neurobiology, Xiangya Medical School of Central South University, Changsha 410013, Hunan Province, China
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16
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La Neve JE, Zitney GP. Use of somatosensory evoked potentials to detect and prevent impending brachial plexus injury during surgical positioning for the treatment of supratentorial pathologies. Neurodiagn J 2014; 54:260-273. [PMID: 25351034 DOI: 10.1080/21646821.2014.11106808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Somatosensory evoked potentials (SSEPs) are widely utilized for the intraoperative detection and prevention of nerve conduction injuries. Their use in identifying position-related injuries to the brachial plexus in patients undergoing supine craniotomies for the treatment of supratentorial pathology is not well documented. This case series describes three instances of unilateral upper extremity SSEP changes in patients positioned for supine craniotomies. In all three cases SSEP responses improved after repositioning. None of the patients exhibited new neurological deficits post-operatively. This case series highlights the importance of vigilant monitoring in the period after final positioning and demonstrates the usefulness of SSEPs as a tool to aid in the early detection and prevention of impending position-related nerve injury.
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17
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Santarius T, Jian BJ, Englot D, McDermott MW. Delayed neurological deficit following resection of tuberculum sellae meningioma: report of two cases, one with permanent and one with reversible visual impairment. Acta Neurochir (Wien) 2014; 156:1099-102. [PMID: 24639145 DOI: 10.1007/s00701-014-2046-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 02/20/2014] [Indexed: 10/25/2022]
Abstract
The most common presentation of patients with tuberculum sellae meningiomas is visual loss, and surgical resection is the main mode of treatment. Preservation of vision is not only the main objective of the surgery; loss of vision is also its main risk. Visual deterioration following surgery is usually apparent immediately post-operatively. Here we present two cases of patients who underwent resection of tuberculum sellae meningioma and whose vision following surgery was initially unchanged until the postoperative day two when dramatic visual deterioration occurred. In the first case this resulted in blindness, whereas in the second case vision recovered back to the preoperative state. The possible mechanisms of visual deterioration and modes of treatment are discussed.
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18
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Kojima H, Kim J, Chan L. Emerging roles of hematopoietic cells in the pathobiology of diabetic complications. Trends Endocrinol Metab 2014; 25:178-87. [PMID: 24507996 PMCID: PMC3975817 DOI: 10.1016/j.tem.2014.01.002] [Citation(s) in RCA: 35] [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: 10/31/2013] [Revised: 12/21/2013] [Accepted: 01/09/2014] [Indexed: 02/08/2023]
Abstract
Diabetic complications encompass macrovascular events, mainly the result of accelerated atherosclerosis, and microvascular events that strike the eye (retinopathy), kidney (nephropathy), and nervous system (neuropathy). The traditional view is that hyperglycemia-induced dysregulated biochemical pathways cause injury and death of cells intrinsic to the organs affected. There is emerging evidence that diabetes compromises the function of the bone marrow (BM), producing a stem cell niche-dependent defect in hematopoietic stem cell mobilization. Furthermore, dysfunctional BM-derived hematopoietic cells contribute to diabetic complications. Thus, BM cells are not only a victim but also an accomplice in diabetes and diabetic complications. Understanding the underlying molecular mechanisms may lead to the development of new therapies to prevent and/or treat diabetic complications by specifically targeting these perpetrators.
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Affiliation(s)
- Hideto Kojima
- Departments of Medicine and Molecular and Cellular Biology, and the Diabetes and Endocrinology Research Center, Baylor College of Medicine, Houston, Texas 77030, USA; Department of Stem Cell Biology and Regenerative Medicine, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan
| | - Jongoh Kim
- Departments of Medicine and Molecular and Cellular Biology, and the Diabetes and Endocrinology Research Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Lawrence Chan
- Departments of Medicine and Molecular and Cellular Biology, and the Diabetes and Endocrinology Research Center, Baylor College of Medicine, Houston, Texas 77030, USA.
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19
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20
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Contribution of macrophages to peripheral neuropathic pain pathogenesis. Life Sci 2013; 93:870-81. [DOI: 10.1016/j.lfs.2013.10.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 09/10/2013] [Accepted: 10/05/2013] [Indexed: 11/24/2022]
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21
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Zenker J, Ziegler D, Chrast R. Novel pathogenic pathways in diabetic neuropathy. Trends Neurosci 2013; 36:439-49. [PMID: 23725712 DOI: 10.1016/j.tins.2013.04.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Revised: 04/20/2013] [Accepted: 04/24/2013] [Indexed: 02/08/2023]
Abstract
Diabetic peripheral neuropathy (DPN) is a common complication affecting more than one third of diabetes mellitus (DM) patients. Although all cellular components participating in peripheral nerve function are exposed to and affected by the metabolic consequences of DM, nodal regions, areas of intense interactions between Schwann cells and axons, may be particularly sensitive to DM-induced alterations. Nodes are enriched in insulin receptors, glucose transporters, Na(+) and K(+) channels, and mitochondria, all implicated in the development and progression of DPN. Latest results particularly reinforce the idea that changes in ion-channel function and energy metabolism, both of which depend on axon-glia crosstalk, are among the important contributors to DPN. These insights provide a basis for new therapeutic approaches aimed at delaying or reversing DPN.
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Affiliation(s)
- Jennifer Zenker
- Department of Medical Genetics, University of Lausanne, 1005 Lausanne, Switzerland
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22
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Proliferating Immature Schwann Cells Contribute to Nerve Regeneration After Ischemic Peripheral Nerve Injury. J Neuropathol Exp Neurol 2012; 71:511-9. [DOI: 10.1097/nen.0b013e318257fe7b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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23
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Lupachyk S, Watcho P, Hasanova N, Julius U, G.Obrosova I. Triglyceride, nonesterified fatty acids, and prediabetic neuropathy: role for oxidative-nitrosative stress. Free Radic Biol Med 2012; 52:1255-63. [PMID: 22366714 PMCID: PMC3312982 DOI: 10.1016/j.freeradbiomed.2012.01.029] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 01/27/2012] [Accepted: 01/27/2012] [Indexed: 01/16/2023]
Abstract
Peripheral neuropathy develops in human subjects with prediabetes and metabolic syndrome before overt hyperglycemia. The contributions of impaired glucose tolerance and insulin signaling, hypertriglyceridemia and/or increased nonesterified fatty acids (NEFA), and hypercholesterolemia to this condition remain unknown. Niacin and its derivatives alleviate dyslipidemia with a minor effect on glucose homeostasis. This study evaluated the roles of impaired glucose tolerance versus dyslipidemia in prediabetic neuropathy using Zucker fatty (fa/fa) rats and the niacin derivative acipimox, as well as the interplay of hypertriglyceridemia, increased NEFA, and oxidative-nitrosative stress. Sixteen-week-old Zucker fatty rats with impaired glucose tolerance, obesity, hyperinsulinemia, hypertriglyceridemia, hypercholesterolemia, and increased NEFA displayed sensory nerve conduction velocity deficit, thermal and mechanical hypoalgesia, and tactile allodynia. Acipimox (100 mg kg(-1) day(-1), 4 weeks) reduced serum insulin, NEFA, and triglyceride concentrations without affecting glucose tolerance and hypercholesterolemia. It alleviated sensory nerve conduction velocity deficit and changes in behavioral measures of sensory function and corrected oxidative-nitrosative stress, but not impaired insulin signaling, in peripheral nerve. Elevated NEFA increased total and mitochondrial superoxide production and NAD(P)H oxidase activity in cultured human Schwann cells. In conclusion, hypertriglyceridemia and/or increased NEFA concentrations cause prediabetic neuropathy through oxidative-nitrosative stress. Lipid-lowering agents and antioxidants may find a use in the management of this condition.
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Affiliation(s)
- Sergey Lupachyk
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA
| | - Pierre Watcho
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA
| | - Nailia Hasanova
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA
| | - Ulrich Julius
- University Hospital, Technical University of Dresden, Dresden Germany
| | - Irina G.Obrosova
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA, USA
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24
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Saleh A, Smith DR, Balakrishnan S, Dunn L, Martens C, Tweed CW, Fernyhough P. Tumor necrosis factor-α elevates neurite outgrowth through an NF-κB-dependent pathway in cultured adult sensory neurons: Diminished expression in diabetes may contribute to sensory neuropathy. Brain Res 2011; 1423:87-95. [PMID: 21985959 DOI: 10.1016/j.brainres.2011.09.029] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 09/14/2011] [Accepted: 09/15/2011] [Indexed: 11/24/2022]
Abstract
The presence of a proinflammatory environment in the sensory neuron axis in diabetes was tested by measuring levels of proinflammatory cytokines in lumbar dorsal root ganglia (DRG) and peripheral nerve from age matched control and streptozotocin (STZ)-induced diabetic rats. The levels of tumor necrosis factor-α (TNFα) and other cytokines were diminished in lumbar DRG from diabetic animals. Consequently, we tested the hypothesis that TNFα modulated axonal plasticity in adult sensory neurons and posited that impairments in this signal transduction pathway may underlie degeneration in diabetic sensory neuropathy. Cultured adult rat sensory neurons were grown under defined conditions and TNFα caused a dose-dependent 2-fold (P<0.05) elevation in neurite outgrowth. Neurons derived from 3 to 5month STZ-induced diabetic rats exhibited significantly reduced levels of neurite outgrowth in response to TNFα. TNFα enhanced NF-κB activity as assessed using Western blotting and plasmid reporter technology. Blockade of TNFα-induction of NF-κB activation caused inhibition of neurite outgrowth in cultured neurons. Immunofluorescent staining for NF-κB subunit p50 within neuronal nuclei revealed that medium to large diameter neurons were most susceptible to NF-κB inhibition and was associated with decreased neurite outgrowth. The results demonstrating reduced cytokine expression in DRG confirm that diabetic sensory neuropathy does not involve a neuroinflammatory component at this stage of the disease in experimental animal models. In addition, it is hypothesized that reduced TNFα expression in the DRG and possibly associated deficits in anterograde transport may contribute to impaired collatoral sprouting and regeneration in target tissue in type 1 diabetes.
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Affiliation(s)
- Ali Saleh
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB, Canada
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25
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Malysz T, Ilha J, Severo do Nascimento P, Faccioni-Heuser MC, De Angelis K, D'agord Schaan B, Achaval M. Exercise training improves the soleus muscle morphology in experimental diabetic nerve regeneration. Muscle Nerve 2011; 44:571-82. [DOI: 10.1002/mus.22133] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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