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Sierawska O, Niedźwiedzka-Rystwej P. Adipokines as potential biomarkers for type 2 diabetes mellitus in cats. Front Immunol 2022; 13:950049. [PMID: 36248900 PMCID: PMC9561307 DOI: 10.3389/fimmu.2022.950049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 09/01/2022] [Indexed: 11/13/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is no longer only a disease of humans, but also of domestic animals, and it particularly affects cats. It is increasingly thought that because of its unique characteristics, T2DM may belong not only to the group of metabolic diseases but also to the group of autoimmune diseases. This is due to the involvement of the immune system in the inflammation that occurs with T2DM. Various pro- and anti-inflammatory substances are secreted, especially cytokines in patients with T2DM. Cytokines secreted by adipose tissue are called adipokines, and leptin, adiponectin, resistin, omentin, TNF-α, and IL-6 have been implicated in T2DM. In cats, approximately 90% of diabetic cases are T2DM. Risk factors include older age, male sex, Burmese breed, presence of obesity, and insulin resistance. Diagnosis of a cat requires repeated testing and is complicated compared to human diagnosis. Based on similarities in the pathogenesis of T2DM between humans and cats, adipokines previously proposed as biomarkers for human T2DM may also serve in the diagnosis of this disease in cats.
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Affiliation(s)
- Olga Sierawska
- Doctoral School, University of Szczecin, Szczecin, Poland
- Institute of Biology, University of Szczecin, Szczecin, Poland
- *Correspondence: Olga Sierawska,
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2
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Eftekharpour E, Fernyhough P. Oxidative Stress and Mitochondrial Dysfunction Associated with Peripheral Neuropathy in Type 1 Diabetes. Antioxid Redox Signal 2022; 37:578-596. [PMID: 34416846 DOI: 10.1089/ars.2021.0152] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Significance: This review highlights the many intracellular processes generating reactive oxygen species (ROS) in the peripheral nervous system in the context of type 1 diabetes. The major sources of superoxide and hydrogen peroxide (H2O2) are described, and scavenging systems are explained. Important roles of ROS in regulating normal redox signaling and in a disease setting, such as diabetes, contributing to oxidative stress and cellular damage are outlined. The primary focus is the role of hyperglycemia in driving elevated ROS production and oxidative stress contributing to neurodegeneration in diabetic neuropathy (within the dorsal root ganglia [DRG] and peripheral nerve). Recent Advances: Contributors to ROS production under high intracellular glucose concentration such as mitochondria and the polyol pathway are discussed. The primarily damaging impact of ROS on multiple pathways including mitochondrial function, endoplasmic reticulum (ER) stress, autophagy, and epigenetic signaling is covered. Critical Issues: There is a strong focus on mechanisms of diabetes-induced mitochondrial dysfunction and how this may drive ROS production (in particular superoxide). The mitochondrial sites of superoxide/H2O2 production via mitochondrial metabolism and aerobic respiration are reviewed. Future Directions: Areas for future development are highlighted, including the need to clarify diabetes-induced changes in autophagy and ER function in neurons and Schwann cells. In addition, more clarity is needed regarding the sources of ROS production at mitochondrial sites under high glucose concentration (and lack of insulin signaling). New areas of study should be introduced to investigate the role of ROS, nuclear lamina function, and epigenetic signaling under diabetic conditions in peripheral nerve.
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Affiliation(s)
- Eftekhar Eftekharpour
- Department of Physiology and Pathophysiology and Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada
| | - Paul Fernyhough
- Department of Pharmacology & Therapeutics, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Canada.,Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada
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3
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Poitras TM, Munchrath E, Zochodne DW. Neurobiological Opportunities in Diabetic Polyneuropathy. Neurotherapeutics 2021; 18:2303-2323. [PMID: 34935118 PMCID: PMC8804062 DOI: 10.1007/s13311-021-01138-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2021] [Indexed: 12/29/2022] Open
Abstract
This review highlights a selection of potential translational directions for the treatment of diabetic polyneuropathy (DPN) currently irreversible and without approved interventions beyond pain management. The list does not include all diabetic targets that have been generated over several decades of research but focuses on newer work. The emphasis is firstly on approaches that support the viability and growth of peripheral neurons and their ability to withstand a barrage of diabetic alterations. We include a section describing Schwann cell targets and finally how mitochondrial damage has been a common element in discussing neuropathic damage. Most of the molecules and pathways described here have not yet reached clinical trials, but many trials have been negative to date. Nonetheless, these failures clear the pathway for new thoughts over reversing DPN.
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Affiliation(s)
- Trevor M Poitras
- Peripheral Nerve Research Laboratory, Division of Neurology, Department of Medicine and the Neuroscience and Mental Health Institute, University of Alberta, 7-132A Clinical Sciences Building, 11350-83 Ave, Edmonton, AB, T6G 2G3, Canada
| | - Easton Munchrath
- Peripheral Nerve Research Laboratory, Division of Neurology, Department of Medicine and the Neuroscience and Mental Health Institute, University of Alberta, 7-132A Clinical Sciences Building, 11350-83 Ave, Edmonton, AB, T6G 2G3, Canada
| | - Douglas W Zochodne
- Peripheral Nerve Research Laboratory, Division of Neurology, Department of Medicine and the Neuroscience and Mental Health Institute, University of Alberta, 7-132A Clinical Sciences Building, 11350-83 Ave, Edmonton, AB, T6G 2G3, 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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Jin HY, Moon SS, Calcutt NA. Lost in Translation? Measuring Diabetic Neuropathy in Humans and Animals. Diabetes Metab J 2021; 45:27-42. [PMID: 33307618 PMCID: PMC7850880 DOI: 10.4093/dmj.2020.0216] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 10/06/2020] [Indexed: 12/21/2022] Open
Abstract
The worldwide diabetes epidemic is estimated to currently afflict almost 500 million persons. Long-term diabetes damages multiple organ systems with the blood vessels, eyes, kidneys and nervous systems being particularly vulnerable. These complications of diabetes reduce lifespan, impede quality of life and impose a huge social and economic burden on both the individual and society. Peripheral neuropathy is a debilitating complication that will impact over half of all persons with diabetes. There is no treatment for diabetic neuropathy and a disturbingly long history of therapeutic approaches showing promise in preclinical studies but failing to translate to the clinic. These failures have prompted re-examination of both the animal models and clinical trial design. This review focuses on the functional and structural parameters used as indices of peripheral neuropathy in preclinical and clinical studies and the extent to which they share a common pathogenesis and presentation. Nerve conduction studies in large myelinated fibers have long been the mainstay of preclinical efficacy screening programs and clinical trials, supplemented by quantitative sensory tests. However, a more refined approach is emerging that incorporates measures of small fiber density in the skin and cornea alongside these traditional assays at both preclinical and clinical phases.
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Affiliation(s)
- Heung Yong Jin
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jeonbuk National University Medical School, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju,
USA
| | - Seong-Su Moon
- Department of Internal Medicine, Dongguk University College of Medicine, Gyeongju,
USA
- Division of Endocrinology, Department of Internal Medicine, Nazareth General Hospital, Daegu,
Korea,
USA
| | - Nigel A. Calcutt
- Department of Pathology, University of California San Diego, La Jolla, CA,
USA
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6
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Paushter AM, Hague DW, Foss KD, Sander WE. Assessment of the cutaneous trunci muscle reflex in neurologically abnormal cats. J Feline Med Surg 2020; 22:1200-1205. [PMID: 32462965 PMCID: PMC10814374 DOI: 10.1177/1098612x20917810] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES The aim of this study was to evaluate the presence of the cutaneous trunci reflex (CTR) in a population of neurologically abnormal cats in regard to age, body condition score (BCS), sex, breed, evidence of traumatic injury, pain, known metabolic disease, mentation, neurolocalization and diagnostic classification. METHODS A retrospective medical record review was performed to identify cats with a history of neurologic disease undergoing a complete neurologic assessment between 24 September 2012 and 20 March 2019. CTR outcome (present, absent), signalment, evidence of traumatic injury, pain, known metabolic disease, mentation, neurolocalization and diagnostic classification were recorded. RESULTS A total of 182 cats were identified. The CTR was present in 118 cats (64.8%) and absent in 64 cats (35.2%). Statistical analysis revealed no association between CTR outcome and age, BCS, sex, breed, evidence of traumatic injury, non-spinal pain, known metabolic disease, mentation, neurolocalization or diagnostic classification. A significant association was found between spinal pain and CTR outcome (P = 0.037). CONCLUSIONS AND RELEVANCE These findings suggest that elicitation of the CTR in the cat can be unreliable. Further prospective controlled studies are warranted to determine whether continued inclusion of the CTR in feline neurologic examinations is justified. Consideration of the reliability of the CTR is indicated, particularly in the context of fractious or anxious patients for which only a limited window for examination may be present.
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Affiliation(s)
- Aaron M Paushter
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Devon W Hague
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Kari D Foss
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - William E Sander
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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7
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Lanigan LG, Russell DS, Woolard KD, Pardo ID, Godfrey V, Jortner BS, Butt MT, Bolon B. Comparative Pathology of the Peripheral Nervous System. Vet Pathol 2020; 58:10-33. [PMID: 33016246 DOI: 10.1177/0300985820959231] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The peripheral nervous system (PNS) relays messages between the central nervous system (brain and spinal cord) and the body. Despite this critical role and widespread distribution, the PNS is often overlooked when investigating disease in diagnostic and experimental pathology. This review highlights key features of neuroanatomy and physiology of the somatic and autonomic PNS, and appropriate PNS sampling and processing techniques. The review considers major classes of PNS lesions including neuronopathy, axonopathy, and myelinopathy, and major categories of PNS disease including toxic, metabolic, and paraneoplastic neuropathies; infectious and inflammatory diseases; and neoplasms. This review describes a broad range of common PNS lesions and their diagnostic criteria and provides many useful references for pathologists who perform PNS evaluations as a regular or occasional task in their comparative pathology practice.
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Abstract
Neuropathic pain represents the extreme in maladaptive pain processing. In itself, it is a disease in which pain has become exaggerated in some combination of scope, severity, character, field, duration, and spontaneity. It is almost certainly an underappreciated, underdiagnosed cause of possible significant patient morbidity in cats. This article explores the basic mechanisms, recognition, known and suspect syndromes, and prospective treatment of feline maladaptive and neuropathic pain.
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Affiliation(s)
- Mark E Epstein
- TotalBond Veterinary Hospital, c/o Forestbrook, 3200 Union Road, Gastonia, NC 28056, USA.
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Muke I, Sprenger A, Bobylev I, Wiemer V, Barham M, Neiss WF, Lehmann HC. Ultrastructural characterization of mitochondrial damage in experimental autoimmune neuritis. J Neuroimmunol 2020; 343:577218. [PMID: 32251941 DOI: 10.1016/j.jneuroim.2020.577218] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/16/2020] [Accepted: 03/18/2020] [Indexed: 12/11/2022]
Abstract
Data are sparse about mitochondrial damage in GBS and in its most frequently employed animal model, experimental autoimmune neuritis (EAN). We here characterized changes in mitochondrial content and morphology at different time points during EAN by use of ultrastructural imaging and immunofluorescent labelling. Histological examination revealed that demyelinated axons and their adjacent Schwann cells showed reduced mitochondrial content and remaining mitochondria appeared swollen with greater diameter in Schwann cells and unmyelinated axons. Our findings indicate that in EAN, particularly mitochondria in Schwann cells are damaged. Further studies are warranted to address whether these changes are amenable to novel, mitoprotective treatments.
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Affiliation(s)
- Ines Muke
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), University of Cologne, Germany
| | - Alina Sprenger
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), University of Cologne, Germany
| | - Ilja Bobylev
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), University of Cologne, Germany
| | - Valerie Wiemer
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, Germany
| | - Mohammed Barham
- Department of Anatomy I, Faculty of Medicine, University of Cologne, Germany
| | | | - Helmar Christoph Lehmann
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), University of Cologne, Germany.
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10
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Graham LC, Grabowska WA, Chun Y, Risacher SL, Philip VM, Saykin AJ, Sukoff Rizzo SJ, Howell GR. Exercise prevents obesity-induced cognitive decline and white matter damage in mice. Neurobiol Aging 2019; 80:154-172. [PMID: 31170535 PMCID: PMC7846054 DOI: 10.1016/j.neurobiolaging.2019.03.018] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 01/12/2023]
Abstract
Obesity in the western world has reached epidemic proportions, and yet the long-term effects on brain health are not well understood. To address this, we performed transcriptional profiling of brain regions from a mouse model of western diet (WD)-induced obesity. Both the cortex and hippocampus from C57BL/6J (B6) mice fed either a WD or a control diet from 2 months of age to 12 months of age (equivalent to midlife in a human population) were profiled. Gene set enrichment analyses predicted that genes involved in myelin generation, inflammation, and cerebrovascular health were differentially expressed in brains from WD-fed compared to control diet-fed mice. White matter damage and cerebrovascular decline were evident in brains from WD-fed mice using immunofluorescence and electron microscopy. At the cellular level, the WD caused an increase in the numbers of oligodendrocytes and myeloid cells suggesting that a WD is perturbing myelin turnover. Encouragingly, cerebrovascular damage and white matter damage were prevented by exercising WD-fed mice despite mice still gaining a significant amount of weight. Collectively, these data show that chronic consumption of a WD in B6 mice causes obesity, neuroinflammation, and cerebrovascular and white matter damage, but these potentially damaging effects can be prevented by modifiable risk factors such as exercise.
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Affiliation(s)
- Leah C Graham
- The Jackson Laboratory, Bar Harbor, ME, USA; Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
| | - Weronika A Grabowska
- The Jackson Laboratory, Bar Harbor, ME, USA; College of the Atlantic, Bar Harbor, ME, USA
| | - Yoona Chun
- The Jackson Laboratory, Bar Harbor, ME, USA
| | - Shannon L Risacher
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Andrew J Saykin
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Gareth R Howell
- The Jackson Laboratory, Bar Harbor, ME, USA; Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA.
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11
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Princz A, Kounakis K, Tavernarakis N. Mitochondrial contributions to neuronal development and function. Biol Chem 2019; 399:723-739. [PMID: 29476663 DOI: 10.1515/hsz-2017-0333] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 02/20/2018] [Indexed: 12/17/2022]
Abstract
Mitochondria are critical to tissues and organs characterized by high-energy demands, such as the nervous system. They provide essential energy and metabolites, and maintain Ca2+ balance, which is imperative for proper neuronal function and development. Emerging findings further underline the role of mitochondria in neurons. Technical advances in the last decades made it possible to investigate key mechanisms in neuronal development and the contribution of mitochondria therein. In this article, we discuss the latest findings relevant to the involvement of mitochondria in neuronal development, placing emphasis on mitochondrial metabolism and dynamics. In addition, we survey the role of mitochondrial energy metabolism and Ca2+ homeostasis in proper neuronal function, and the involvement of mitochondria in axon myelination.
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Affiliation(s)
- Andrea Princz
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, N. Plastira 100, Vassilika Vouton, Heraklion 70013, Crete, Greece
- Department of Biology, University of Crete, N. Plastira 100, Vassilika Vouton, Heraklion 70013, Crete, Greece
| | - Konstantinos Kounakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, N. Plastira 100, Vassilika Vouton, Heraklion 70013, Crete, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, N. Plastira 100, Vassilika Vouton, Heraklion 70013, Crete, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, N. Plastira 100, Vassilika Vouton, Heraklion 70013, Crete, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, N. Plastira 100, Vassilika Vouton, Heraklion 70013, Crete, Greece
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12
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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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Al-Bagdadi F, Schumacher J, Carter J, Tóth F, Henry RW. Determining Direction of Axonal Flow in the Equine Ramus Communicans by Ultrastructural Examination of the Plantar Nerves 2 Months after Transecting the Ramus. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2018; 24:64-68. [PMID: 29362000 DOI: 10.1017/s1431927617012818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The ramus communicans, neural connection between medial and lateral plantar nerves of the horse, was transected to determine the degree to which medial and lateral plantar nerves contribute to the plantar ramus. After 2 months, sections of plantar nerves immediately proximal and distal to the communicating branch were collected and processed for electron microscopy. All examined nerves had undergone Wallerian degeneration and contained regenerating and mature fibers. Layers of the myelin sheath were separated by spaces and vacuoles, indicating demyelination of medial and lateral plantar nerves. Shrunken axons varied in diameter and were surrounded by an irregular axolemma. Shrunken axoplasm of both myelinated and non-myelinated fibers contained ruptured mitochondria and cristae, disintegrating cytoskeleton, and vacuoles of various sizes. The cytoplasm of neurolemmocytes contained various-sized vesicles, ruptured mitochondria within a fragile basal lamina and myelin whorls of multilayered structures indicative of Wallerian degeneration. These ultrastructural changes, found proximal and distal to the ramus in medial and lateral plantar nerves, suggest that axonal flow is bi-directional through the ramus communicans of the pelvic limbs of horses, a previously unreported finding. As well, maturity of nerves proximal and distal to the ramus indicates that all nerve fibers do not pass through the ramus.
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Affiliation(s)
- Fakhri Al-Bagdadi
- 1Department of Comparative Biomedical Sciences,School of Veterinary Medicine,Louisiana State University,Baton Rouge,LA 70803,USA
| | - Jim Schumacher
- 2Department of Large Animal Clinical Sciences,College of Veterinary Medicine,University of Tennessee,Knoxville,TN 37996,USA
| | - Jessi Carter
- 2Department of Large Animal Clinical Sciences,College of Veterinary Medicine,University of Tennessee,Knoxville,TN 37996,USA
| | - Ferenc Tóth
- 2Department of Large Animal Clinical Sciences,College of Veterinary Medicine,University of Tennessee,Knoxville,TN 37996,USA
| | - Robert W Henry
- 3College of Veterinary Medicine,Lincoln Memorial University,Harrogate,TN 37752,USA
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Ino D, Iino M. Schwann cell mitochondria as key regulators in the development and maintenance of peripheral nerve axons. Cell Mol Life Sci 2017; 74:827-835. [PMID: 27638763 PMCID: PMC11107563 DOI: 10.1007/s00018-016-2364-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/29/2016] [Accepted: 09/09/2016] [Indexed: 01/13/2023]
Abstract
Formation of myelin sheaths by Schwann cells (SCs) enables rapid and efficient transmission of action potentials in peripheral axons, and disruption of myelination results in disorders that involve decreased sensory and motor functions. Given that construction of SC myelin requires high levels of lipid and protein synthesis, mitochondria, which are pivotal in cellular metabolism, may be potential regulators of the formation and maintenance of SC myelin. Supporting this notion, abnormal mitochondria are found in SCs of neuropathic peripheral nerves in both human patients and the relevant animal models. However, evidence for the importance of SC mitochondria in myelination has been limited, until recently. Several studies have recently used genetic approaches that allow SC-specific ablation of mitochondrial metabolic activity in living animals to show the critical roles of SC mitochondria in the development and maintenance of peripheral nerve axons. Here, we review current knowledge about the involvement of SC mitochondria in the formation and dysfunction of myelinated axons in the peripheral nervous system.
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Affiliation(s)
- Daisuke Ino
- Department of Pharmacology, The University of Tokyo Graduate School of Medicine, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
- Laboratory for Cell Polarity Regulation, RIKEN Quantitative Biology Center, 6-2-3, Furuedai, Suita, Osaka, 565-0874, Japan
| | - Masamitsu Iino
- Department of Pharmacology, The University of Tokyo Graduate School of Medicine, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
- Division of Cellular and Molecular Pharmacology, Nihon University School of Medicine, 30-1, Oyaguchi kami-cho, Itabashi-ku, Tokyo, 173-8610, Japan.
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15
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Polle F, Andrews FM, Gillon T, Eades SC, McConnico RS, Strain GM, Valberg SJ, Guo LT, Shelton GD. Suspected congenital centronuclear myopathy in an Arabian-cross foal. J Vet Intern Med 2016; 28:1886-91. [PMID: 25410957 PMCID: PMC4895639 DOI: 10.1111/jvim.12438] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/22/2014] [Accepted: 07/23/2014] [Indexed: 11/30/2022] Open
Affiliation(s)
- F Polle
- Equine Health Studies Program, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA
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16
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An Introduction to the History and Controversies of Animal Models of Diabetic Neuropathy. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 127:45-52. [PMID: 27133144 DOI: 10.1016/bs.irn.2016.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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17
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Abstract
The study of diabetic neuropathy has relied primarily on the use of streptozotocin-treated rat and mouse models of type 1 diabetes. This chapter will review the creation and use of other rodent models that have been developed in order to investigate the contribution of factors besides insulin deficiency to the development and progression of diabetic neuropathy as it occurs in obesity, type 1 or type 2 diabetes. Diabetic peripheral neuropathy is a complex disorder with multiple mechanisms contributing to its development and progression. Even though many animal models have been developed and investigated, no single model can mimic diabetic peripheral neuropathy as it occurs in humans. Nonetheless, animal models can play an important role in improving our understanding of the etiology of diabetic peripheral neuropathy and in performing preclinical screening of potential new treatments. To date treatments found to be effective for diabetic peripheral neuropathy in rodent models have failed in clinical trials. However, with the identification of new endpoints for the early detection of diabetic peripheral neuropathy and the understanding that a successful treatment may require a combination therapeutic approach there is hope that an effective treatment will be found.
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Affiliation(s)
- M A Yorek
- Iowa City Health Care System, Iowa City, IA, United States; University of Iowa, Iowa City, IA, United States; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, United States.
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Mhlanga-Mutangadura T, Johnson GS, Ashwini A, Shelton GD, Wennogle SA, Johnson GC, Kuroki K, O'Brien DP. A Homozygous RAB3GAP1:c.743delC Mutation in Rottweilers with Neuronal Vacuolation and Spinocerebellar Degeneration. J Vet Intern Med 2016; 30:813-8. [PMID: 26968732 PMCID: PMC4913561 DOI: 10.1111/jvim.13921] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 12/28/2015] [Accepted: 02/11/2016] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND A variety of presumed hereditary, neurologic diseases have been reported in young Rottweilers. Overlapping ages of onset and clinical signs have made antemortem diagnosis difficult. One of these diseases, neuronal vacuolation and spinocerebellar degeneration (NVSD) shares clinical and histological features with polyneuropathy with ocular abnormalities and neuronal vacuolation (POANV), a recently described hereditary disease in Black Russian Terriers (BRTs). Dogs with POANV harbor mutations in RAB3GAP1 which codes for a protein involved in membrane trafficking. HYPOTHESIS Rottweilers with NVSD will be homozygous for the RAB3GAP1:c.743delC allele associated with POANV in BRTs. ANIMALS Eight Rottweilers with NVSD confirmed at necropsy, 128 Rottweilers without early onset neurologic signs, and 468 randomly selected dogs from 169 other breeds. METHODS Retrospective case-control study. Dogs were genotyped for the RAB3GAP1:c.743delC allele with an allelic discrimination assay. RESULTS All 8 NVSD-affected dogs were homozygous for the RAB3GAP1:c.743delC allele while the 128 NVSD-free Rottweilers were either homozygous for the reference allele (n = 105) or heterozygous (n = 23) and the 468 genotyped dogs from other breeds were all homozygous for the reference allele. CONCLUSIONS AND CLINICAL IMPORTANCE The RAB3GAP1:c.743delC mutation is associated with a similar phenotype in Rottweilers and BRTs. Identification of the mutation permits a DNA test that can aid in the diagnosis of NVSD and identify carriers of the trait so that breeders can avoid producing affected dogs. Disruption of membrane trafficking could explain the neuronal vacuolation seen in NVSD and other spongiform encephalopathies.
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Affiliation(s)
- T Mhlanga-Mutangadura
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO
| | - G S Johnson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO
| | - A Ashwini
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO
| | - G D Shelton
- Department of Pathology, University of California San Diego, La Jolla, CA
| | - S A Wennogle
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO
| | - G C Johnson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO
| | - K Kuroki
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO
| | - D P O'Brien
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO
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Abstract
Diabetic neuropathy is a dying back neurodegenerative disease of the peripheral nervous system where mitochondrial dysfunction has been implicated as an etiological factor. Diabetes (type 1 or type 2) invokes an elevation of intracellular glucose concentration simultaneously with impaired growth factor support by insulin, and this dual alteration triggers a maladaptation in metabolism of adult sensory neurons. The energy sensing pathway comprising the AMP-activated protein kinase (AMPK)/sirtuin (SIRT)/peroxisome proliferator-activated receptor-γ coactivator α (PGC-1α) signaling axis is the target of these damaging changes in nutrient levels, e.g., induction of nutrient stress, and loss of insulin-dependent growth factor support and instigates an aberrant metabolic phenotype characterized by a suppression of mitochondrial oxidative phosphorylation and shift to anaerobic glycolysis. There is discussion of how this loss of mitochondrial function and transition to overreliance on glycolysis contributes to the diminishment of collateral sprouting and axon regeneration in diabetic neuropathy in the context of the highly energy-consuming nerve growth cone.
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Affiliation(s)
- Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, R4046-351 Taché Ave, Winnipeg, Manitoba, R2H 2A6, Canada.
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, R3E 0T6, Canada.
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Habash T, Saleh A, Roy Chowdhury SK, Smith DR, Fernyhough P. The proinflammatory cytokine, interleukin-17A, augments mitochondrial function and neurite outgrowth of cultured adult sensory neurons derived from normal and diabetic rats. Exp Neurol 2015; 273:177-89. [PMID: 26321687 DOI: 10.1016/j.expneurol.2015.08.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 07/31/2015] [Accepted: 08/24/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND Diabetic neuropathy comprises dying back of nerve endings that reflects impairment in axonal plasticity and regenerative nerve growth. Metabolic changes in diabetes can lead to a dysregulation of hormonal mediators, such as cytokines, that may constrain distal nerve fiber growth. Interleukin-17 (IL-17A), a proinflammatory and neurotropic cytokine produced by T-cells, was significantly reduced in sciatic nerve of streptozotocin (STZ)-diabetic rats. Thus we studied the effect of IL-17A on the phenotype of sensory neurons derived from age matched control or type 1 diabetic rats. The aims were to determine the ability of IL-17A to enhance neurite outgrowth in cultured sensory neurons, investigate the signaling pathways activated by IL-17A, study the role of mitochondria and mechanistically link to neurite outgrowth. RESULTS IL-17A (10 ng/ml; p<0.05) significantly and dose-dependently increased total neurite outgrowth in cultures of adult dorsal root ganglia (DRG) sensory neurons derived from both control and streptozotocin (STZ)-diabetic rats. This enhancement was mediated by IL-17A-dependent activation of extracellular-regulated protein kinase (ERK) and phosphoinositide-3 kinase (PI-3K) signal transduction pathways. Pharmacological blockade of one of these activated pathways triggered complete inhibition of neurite outgrowth. IL-17A augmented mitochondrial bioenergetic function of sensory neurons derived from control or diabetic rats and this was also mediated via ERK or PI-3K. IL-17A-dependent elevation of bioenergetic function was associated with augmented expression of proteins of the mitochondrial electron transport system complexes. CONCLUSIONS IL-17A enhanced axonal plasticity through activation of ERK and PI-3K pathways and was associated with augmented mitochondrial bioenergetic function in sensory neurons.
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Affiliation(s)
- Tarek Habash
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada; Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB R3E 0T6, Canada
| | - Ali Saleh
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada
| | - Subir K Roy Chowdhury
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada
| | - Darrell R Smith
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada
| | - Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada; Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB R3E 0T6, Canada.
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21
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Biessels GJ, Bril V, Calcutt NA, Cameron NE, Cotter MA, Dobrowsky R, Feldman EL, Fernyhough P, Jakobsen J, Malik RA, Mizisin AP, Oates PJ, Obrosova IG, Pop-Busui R, Russell JW, Sima AA, Stevens MJ, Schmidt RE, Tesfaye S, Veves A, Vinik AI, Wright DE, Yagihashi S, Yorek MA, Ziegler D, Zochodne DW. Phenotyping animal models of diabetic neuropathy: a consensus statement of the diabetic neuropathy study group of the EASD (Neurodiab). J Peripher Nerv Syst 2015; 19:77-87. [PMID: 24934510 DOI: 10.1111/jns5.12072] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 03/27/2014] [Accepted: 04/07/2014] [Indexed: 11/28/2022]
Abstract
NIDDK, JDRF, and the Diabetic Neuropathy Study Group of EASD sponsored a meeting to explore the current status of animal models of diabetic peripheral neuropathy. The goal of the workshop was to develop a set of consensus criteria for the phenotyping of rodent models of diabetic neuropathy. The discussion was divided into five areas: (1) status of commonly used rodent models of diabetes, (2) nerve structure, (3) electrophysiological assessments of nerve function, (4) behavioral assessments of nerve function, and (5) the role of biomarkers in disease phenotyping. Participants discussed the current understanding of each area, gold standards (if applicable) for assessments of function, improvements of existing techniques, and utility of known and exploratory biomarkers. The research opportunities in each area were outlined, providing a possible roadmap for future studies. The meeting concluded with a discussion on the merits and limitations of a unified approach to phenotyping rodent models of diabetic neuropathy and a consensus formed on the definition of the minimum criteria required for establishing the presence of the disease. A neuropathy phenotype in rodents was defined as the presence of statistically different values between diabetic and control animals in 2 of 3 assessments (nocifensive behavior, nerve conduction velocities, or nerve structure). The participants propose that this framework would allow different research groups to compare and share data, with an emphasis on data targeted toward the therapeutic efficacy of drug interventions.
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22
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Hamid HS, Mervak CM, Münch AE, Robell NJ, Hayes JM, Porzio MT, Singleton JR, Smith AG, Feldman EL, Lentz SI. Hyperglycemia- and neuropathy-induced changes in mitochondria within sensory nerves. Ann Clin Transl Neurol 2014; 1:799-812. [PMID: 25493271 PMCID: PMC4241807 DOI: 10.1002/acn3.119] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 08/19/2014] [Accepted: 08/22/2014] [Indexed: 02/04/2023] Open
Abstract
Objective This study focused on altered mitochondrial dynamics as a potential mechanism for diabetic peripheral neuropathy (DPN). We employed both an in vitro sensory neuron model and an in situ analysis of human intraepidermal nerve fibers (IENFs) from cutaneous biopsies to measure alterations in the size distribution of mitochondria as a result of hyperglycemia and diabetes, respectively. Methods Neurite- and nerve-specific mitochondrial signals within cultured rodent sensory neurons and human IENFs were measured by employing a three-dimensional visualization and quantification technique. Skin biopsies from distal thigh (DT) and distal leg (DL) were analyzed from three groups of patients; patients with diabetes and no DPN, patients with diabetes and confirmed DPN, and healthy controls. Results This analysis demonstrated an increase in mitochondria distributed within the neurites of cultured sensory neurons exposed to hyperglycemic conditions. Similar changes were observed within IENFs of the DT in DPN patients compared to controls. This change was represented by a significant shift in the size frequency distribution of mitochondria toward larger mitochondria volumes within DT nerves of DPN patients. There was a length-dependent difference in mitochondria within IENFs. Distal leg IENFs from control patients had a significant shift toward larger volumes of mitochondrial signal compared to DT IENFs. Interpretation The results of this study support the hypothesis that altered mitochondrial dynamics may contribute to DPN pathogenesis. Future studies will examine the potential mechanisms that are responsible for mitochondrial changes within IENFs and its effect on DPN pathogenesis.
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Affiliation(s)
- Hussein S Hamid
- University of Michigan Medical School, University of Michigan Ann Arbor, Michigan, 48109
| | - Colin M Mervak
- Department of Neurology, University of Michigan Ann Arbor, Michigan, 48109
| | - Alexandra E Münch
- Division on Metabolism Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Ann Arbor, Michigan, 48105
| | - Nicholas J Robell
- Department of Neurology, University of Michigan Ann Arbor, Michigan, 48109
| | - John M Hayes
- Department of Neurology, University of Michigan Ann Arbor, Michigan, 48109
| | - Michael T Porzio
- Department of Neurology, University of Utah School of Medicine Salt Lake City, Utah, 84132
| | - J Robinson Singleton
- Department of Neurology, University of Utah School of Medicine Salt Lake City, Utah, 84132
| | - A Gordon Smith
- Department of Neurology, University of Utah School of Medicine Salt Lake City, Utah, 84132
| | - Eva L Feldman
- Department of Neurology, University of Michigan Ann Arbor, Michigan, 48109
| | - Stephen I Lentz
- Division on Metabolism Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Ann Arbor, Michigan, 48105
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Aleman M, Dickinson PJ, Williams DC, Sturges BK, LeCouteur RA, Vernau KM, Shelton GD. Electrophysiologic confirmation of heterogenous motor polyneuropathy in young cats. J Vet Intern Med 2014; 28:1789-98. [PMID: 25231268 PMCID: PMC4895637 DOI: 10.1111/jvim.12439] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 05/06/2014] [Accepted: 07/23/2014] [Indexed: 12/11/2022] Open
Abstract
Background Reports of motor polyneuropathies in young cats are scarce. Further, in‐depth electrophysiologic evaluation to confirm a motor polyneuropathy in young cats of various breeds other than 2 Bengal cats is lacking. Hypothesis/Objectives To confirm a motor polyneuropathy in young cats of various breeds. Animals Five young cats with heterogenous chronic or relapsing episodes of weakness. Methods Retrospective case series. Cats were presented for evaluation of generalized neuromuscular disease and underwent electrophysiologic examination including electromyography, nerve conduction, and repetitive nerve stimulation. Minimum database and muscle and nerve biopsy analyses were carried out. Descriptive statistics were performed. Results Disease onset was at 3 months to 1 year of age and in 5 breeds. The most common clinical sign (5 of 5 cats) was weakness. Additional neurologic deficits consisted of palmigrade and plantigrade posture (4/4), low carriage of the head and tail (4/4), and variable segmental reflex deficits (5/5). Motor nerve conduction studies were abnormal for the ulnar (4/4), peroneal (5/5), and tibial (2/2) nerves (increased latencies, reduced amplitudes, slow velocities). A marked decrement was observed on repetitive nerve stimulation of the peroneal nerve in 3 cats for which autoimmune myasthenia gravis was ruled out. All sensory nerve conduction studies were normal. Histologic evaluation of muscle and nerve biopsies supported heterogenous alterations consistent with motor polyneuropathy with distal nerve fiber loss. Conclusions and Clinical Importance Heterogenous motor polyneuropathies should be considered in young cats of any breed and sex that are presented with relapsing or progressive generalized neuromuscular disease.
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Affiliation(s)
- M Aleman
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA
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24
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Calcium signalling in sensory neurones and peripheral glia in the context of diabetic neuropathies. Cell Calcium 2014; 56:362-71. [PMID: 25149565 DOI: 10.1016/j.ceca.2014.07.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/11/2014] [Accepted: 07/12/2014] [Indexed: 12/14/2022]
Abstract
Peripheral sensory nervous system is comprised of neurones with their axons and neuroglia that includes satellite glial cells in sensory ganglia, myelinating, non-myelinating and perisynaptic Schwann cells. Pathogenesis of peripheral diabetic polyneuropathies is associated with aberrant function of both neurones and glia. Deregulated Ca(2+) homoeostasis and aberrant Ca(2+) signalling in neuronal and glial elements contributes to many forms of neuropathology and is fundamental to neurodegenerative diseases. In diabetes both neurones and glia experience metabolic stress and mitochondrial dysfunction which lead to deregulation of Ca(2+) homeostasis and Ca(2+) signalling, which in their turn lead to pathological cellular reactions contributing to development of diabetic neuropathies. Molecular cascades responsible for Ca(2+) homeostasis and signalling, therefore, can be regarded as potential therapeutic targets.
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Ariza L, Pagès G, García-Lareu B, Cobianchi S, Otaegui PJ, Ruberte J, Chillón M, Navarro X, Bosch A. Experimental diabetes in neonatal mice induces early peripheral sensorimotor neuropathy. Neuroscience 2014; 274:250-9. [PMID: 24846610 DOI: 10.1016/j.neuroscience.2014.05.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 04/23/2014] [Accepted: 05/09/2014] [Indexed: 10/25/2022]
Abstract
Animal models of diabetes do not reach the severity of human diabetic neuropathy but relatively mild neurophysiological deficits and minor morphometric changes. The lack of degenerative neuropathy in diabetic rodent models seems to be a consequence of the shorter length of the axons or the shorter animal life span. Diabetes-induced demyelination needs many weeks or even months before it can be evident by morphometrical analysis. In mice myelination of the peripheral nervous system starts at the prenatal period and it is complete several days after birth. Here we induced experimental diabetes to neonatal mice and we evaluated its effect on the peripheral nerve 4 and 8 weeks after diabetes induction. Neurophysiological values showed a decline in sensory nerve conduction velocity at both time-points. Morphometrical analysis of the tibial nerve demonstrated a decrease in the number of myelinated fibers, fiber size and myelin thickness at both time-points studied. Moreover, aldose reductase and poly(ADP-ribose) polymerase activities were increased even if the amount of the enzyme was not affected. Thus, type 1 diabetes in newborn mice induces early peripheral neuropathy and may be a good model to assay pharmacological or gene therapy strategies to treat diabetic neuropathy.
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Affiliation(s)
- L Ariza
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - G Pagès
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - B García-Lareu
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - S Cobianchi
- Department of Cell Biology, Physiology and Immunology and Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Spain
| | - P J Otaegui
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - J Ruberte
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain; Department of Animal Health and Anatomy, Veterinary School, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - M Chillón
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain; Institut Català de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - X Navarro
- Department of Cell Biology, Physiology and Immunology and Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Spain
| | - A Bosch
- Center of Animal Biotechnology and Gene Therapy (CBATEG), Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain.
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Spoo JW, Shelton GD. Recurrent gastric dilatation and intestinal dysmotility possibly resulting from autonomic neuropathy in a Great Dane. J Am Anim Hosp Assoc 2014; 50:221-6. [PMID: 24659724 DOI: 10.5326/jaaha-ms-6176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A 5 yr old female spayed Great Dane was presented for recurrent episodes of gastric dilatation, intestinal dysmotility, and one episode of gastric rupture. Numerous hematologic, radiographic, and endocrine diagnostic tests were performed with no identifiable underlying cause. Many risk factors have been identified for gastric dilatation and most were present in this Great Dane. A number of symptomatic treatments, aimed primarily at altering the gastrointestinal tract flora and motility were tried, but failed to influence the clinical course of the disease. The dog continued to worsen, experienced more frequent episodes of gastric dilatation, and developed generalized muscle atrophy. Biopsies were collected from the biceps femoris and triceps brachii muscles. A pattern of denervation atrophy was evident in both muscles, consistent with polyneuropathy. The owners elected humane euthanasia and a necropsy was performed. A striking finding at necropsy was severe loss of myelinated fibers with extensive endoneurial fibrosis in the vagus nerve, consistent with an autonomic neuropathy. Autonomic neuropathy is a previously unexplored cause of gastric dilatation and intestinal dysmotility in dogs. These findings should open new directions for exploring pathogenic mechanisms for gastric dilatation in this species.
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Homs J, Pagès G, Ariza L, Casas C, Chillón M, Navarro X, Bosch A. Intrathecal administration of IGF-I by AAVrh10 improves sensory and motor deficits in a mouse model of diabetic neuropathy. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2014; 1:7. [PMID: 26015946 PMCID: PMC4365866 DOI: 10.1038/mtm.2013.7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 11/07/2013] [Indexed: 01/09/2023]
Abstract
Different adeno-associated virus (AAV) serotypes efficiently transduce neurons from central and peripheral nervous systems through various administration routes. Direct administration of the vectors to the cerebrospinal fluid (CSF) could be an efficient and safe strategy. Here, we show that lumbar puncture of a nonhuman AAV leads to wide and stable distribution of the vector along the spinal cord in adult mice. AAVrh10 efficiently and specifically infects neurons, both in dorsal root ganglia (60% total sensory neurons) and in the spinal cord (up to one-third of α-motor neurons). As a proof of concept, we demonstrate the efficacy of AAVrh10 in a mouse model of diabetic neuropathy, in which intrathecal delivery of the vector coding for insulin-like growth factor (IGF-I) favored the release of the therapeutic protein into the CSF through its expression by sensory and motor neurons. IGF-I-treated diabetic animals showed increased vascular endothelial growth factor expression, activation of Akt/PI3K pathway, and stimulated nerve regeneration and myelination in injured limbs. Moreover, we achieved restoration of nerve conduction velocities in both sensory and motor nerves by AAVrh10, whereas we reached only sensory nerve improvement with AAV1. Our results indicate that intrathecal injection of AAVrh10 is a promising tool to design gene therapy approaches for sensorimotor diseases.
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Affiliation(s)
- Judit Homs
- Department of Biochemistry and Molecular Biology, Center of Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona , Bellaterra, Barcelona, Spain
| | - Gemma Pagès
- Department of Biochemistry and Molecular Biology, Center of Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona , Bellaterra, Barcelona, Spain
| | - Lorena Ariza
- Department of Biochemistry and Molecular Biology, Center of Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona , Bellaterra, Barcelona, Spain
| | - Caty Casas
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona , Bellaterra, Barcelona, Spain ; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III , Spain
| | - Miguel Chillón
- Department of Biochemistry and Molecular Biology, Center of Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona , Bellaterra, Barcelona, Spain ; Institut Català de Recerca i Estudis Avançats (ICREA) , Barcelona, Spain
| | - Xavier Navarro
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona , Bellaterra, Barcelona, Spain ; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III , Spain
| | - Assumpció Bosch
- Department of Biochemistry and Molecular Biology, Center of Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autònoma de Barcelona , Bellaterra, Barcelona, Spain
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Abstract
As ensheathing and secretory cells, Schwann cells are a ubiquitous and vital component of the endoneurial microenvironment of peripheral nerves. The interdependence of axons and their ensheathing Schwann cells predisposes each to the impact of injury in the other. Further, the dependence of the blood-nerve interface on trophic support from Schwann cells during development, adulthood, and after injury suggests these glial cells promote the structural and functional integrity of nerve trunks. Here, the developmental origin, injury-induced changes, and mature myelinating and nonmyelinating phenotypes of Schwann cells are reviewed prior to a description of nerve fiber pathology and consideration of pathogenic mechanisms in human and experimental diabetic neuropathy. A fundamental role for aldose-reductase-containing Schwann cells in the pathogenesis of diabetic neuropathy, as well as the interrelationship of pathogenic mechanisms, is indicated by the sensitivity of hyperglycemia-induced biochemical alterations, such as polyol pathway flux, formation of reactive oxygen species, generation of advanced glycosylation end products (AGEs) and deficient neurotrophic support, to blocking polyol pathway flux.
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Affiliation(s)
- Andrew P Mizisin
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA, USA.
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Rutigliano L, Corradetti B, Valentini L, Bizzaro D, Meucci A, Cremonesi F, Lange-Consiglio A. Molecular characterization and in vitro differentiation of feline progenitor-like amniotic epithelial cells. Stem Cell Res Ther 2013; 4:133. [PMID: 24405576 PMCID: PMC3854755 DOI: 10.1186/scrt344] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 10/25/2013] [Indexed: 12/21/2022] Open
Abstract
Introduction While amniotic mesenchymal cells have been isolated and characterized in different species, amniotic epithelial cells (AECs) have been found only in humans and horses and are recently considered valid candidates in regenerative medicine. The aim of this work is to obtain and characterize, for the first time in the feline species, presumptive stem cells from the epithelial portion of the amnion (AECs) to be used for clinical applications. Methods In our study, we molecularly characterized and induced in vitro differentiation of feline AECs, obtained after enzymatic digestion of amnion. Results AECs displayed a polygonal morphology and the mean doubling time value was 1.94 ± 0.04 days demonstrating the high proliferating capacity of these cells. By RT-PCR, AECs expressed pluripotent (Oct4, Nanog) and some mesenchymal markers (CD166, CD44) suggesting that an epithelial-mesenchymal transition may occur in these cells that lack the hematopoietic marker CD34. Cells also showed the expression of embryonic marker SSEA-4, but not SSEA-3, as demonstrated by immunocytochemistry and flow cytometry. Moreover, the possibility to use feline AECs in cell therapies resides in their low immunogenicity, due to the absence of MHC-II antigen expression. After induction, AECs differentiated into the mesodermic and ectodermic lineages, demonstrating high plasticity. Conclusions In conclusion, feline AECs appear to be a readily obtainable, highly proliferative, multipotent and non-immunogenic cell line from a source that may represent a good model system for stem cell biology and be useful in allogenic cell-based therapies in order to treat tissue lesions, especially with loss of substance.
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The adjuvant effect of hypertension upon diabetic peripheral neuropathy in experimental type 2 diabetes. Neurobiol Dis 2013; 62:18-30. [PMID: 23938761 DOI: 10.1016/j.nbd.2013.07.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 07/17/2013] [Accepted: 07/29/2013] [Indexed: 01/30/2023] Open
Abstract
Type 2 diabetes (DM) is the most common cause of peripheral neuropathy in the Western world. A comorbidity, hypertension, has been speculated to contribute to initiation or worsening of diabetic peripheral neuropathy. We studied adult rat models using genetic strains with DM (Zucker Diabetic Fat rats)±hypertension (HTN (ZSF-1 rats)) to investigate the relative contributions of DM and HTN and the potential for additive effects of HTN upon existing DM for the development of peripheral neuropathy. Long duration sensorimotor behavioral and electrophysiological testing was complemented by histological and molecular methods. Only DM led to tactile and thermal hyperalgesia and affected motor nerve electrophysiology. Although DM led to marked loss of sensory amplitudes and to sensory conduction slowing, a mild additive effect from HTN contributed after 6months of DM with worsening of slowing of sensory nerve conduction velocities, but without effect upon sensory amplitudes. At the sensory dominant sural nerve, mild (<10%) but greater degrees of myelin thinning were noted with DM and HTN combined, suggesting a mild additive effect. Matrix metalloproteinase (MMP) expression was increased only at the sural nerve in the presence of HTN with co-localization to Schwann cells and myelin. The effects of DM and HTN upon peripheral nerve are dissimilar, with HTN contributing to MMP upregulation at the sites of myelin thinning at sensory nerve fibers, potentially worsening comorbid DM. Together, our results indicate that HTN has a mild additive contribution to diabetic peripheral neuropathy at sensory peripheral nerve fibers manifesting with the loss of myelin thickness.
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Electrodiagnostic testing and histopathologic changes confirm peripheral nervous system myelin abnormalities in the feline model of niemann-pick disease type C. J Neuropathol Exp Neurol 2013; 72:256-62. [PMID: 23399903 DOI: 10.1097/nen.0b013e318286587f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Niemann-Pick disease type C (NPC disease) is an incurable, neurodegenerative, autosomal recessive disease caused by mutations in either the NPC1 or the NPC2 gene. These mutations affect the intracellular trafficking of lipids and cholesterol, resulting in the intralysosomal accumulation of unesterified cholesterol and glycosphingolipids. These abnormalities are associated with clinical ataxia and impaired motor and intellectual development, and death frequently occurs in adolescence. The incidence of peripheral neuropathy in NPC patients is not known. We investigated peripheral nerves in the naturally occurring feline model of NPC disease, which has proven to be critical for understanding both disease pathogenesis and for evaluating experimental therapies. Electrodiagnostic studies revealed significantly slowed motor and sensory nerve conduction velocities in affected cats in the absence of altered M-wave amplitude. Histologic and ultrastructural analyses showed thin myelin sheaths, membranous debris, myelin figures, lipid vacuolization of Schwann cell cytoplasm, and expanded paranodal areas. Axonal degeneration was not identified. There was a shift to small myelinated fibers in affected cats, and there were significant decreases in fiber diameter, axon diameter, and myelin thickness. These changes were similar to those described in the murine NPC disease model and in rare patients in whom nerve biopsy has been performed. Characterization of the demyelinating neuropathy is necessary for evaluating clinical trials that target only the CNS aspects of NPC.
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Abstract
It is increasingly apparent that not only is a cure for the current worldwide diabetes epidemic required, but also for its major complications, affecting both small and large blood vessels. These complications occur in the majority of individuals with both type 1 and type 2 diabetes. Among the most prevalent microvascular complications are kidney disease, blindness, and amputations, with current therapies only slowing disease progression. Impaired kidney function, exhibited as a reduced glomerular filtration rate, is also a major risk factor for macrovascular complications, such as heart attacks and strokes. There have been a large number of new therapies tested in clinical trials for diabetic complications, with, in general, rather disappointing results. Indeed, it remains to be fully defined as to which pathways in diabetic complications are essentially protective rather than pathological, in terms of their effects on the underlying disease process. Furthermore, seemingly independent pathways are also showing significant interactions with each other to exacerbate pathology. Interestingly, some of these pathways may not only play key roles in complications but also in the development of diabetes per se. This review aims to comprehensively discuss the well validated, as well as putative mechanisms involved in the development of diabetic complications. In addition, new fields of research, which warrant further investigation as potential therapeutic targets of the future, will be highlighted.
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Affiliation(s)
- Josephine M Forbes
- Diabetes Division, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
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Xie F, Fu H, Hou JF, Jiao K, Costigan M, Chen J. High energy diets-induced metabolic and prediabetic painful polyneuropathy in rats. PLoS One 2013; 8:e57427. [PMID: 23451227 PMCID: PMC3581455 DOI: 10.1371/journal.pone.0057427] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 01/22/2013] [Indexed: 12/16/2022] Open
Abstract
To establish the role of the metabolic state in the pathogenesis of polyneuropathy, an age- and sex-matched, longitudinal study in rats fed high-fat and high-sucrose diets (HFSD) or high-fat, high-sucrose and high-salt diets (HFSSD) relative to controls was performed. Time courses of body weight, systolic blood pressure, fasting plasma glucose (FPG), insulin, free fatty acids (FFA), homeostasis model assessment-insulin resistance index (HOMA-IR), thermal and mechanical sensitivity and motor coordination were measured in parallel. Finally, large and small myelinated fibers (LMF, SMF) as well as unmyelinated fibers (UMF) in the sciatic nerves and ascending fibers in the spinal dorsal column were quantitatively assessed under electron microscopy. The results showed that early metabolic syndrome (hyperinsulinemia, dyslipidemia, and hypertension) and prediabetic conditions (impaired fasting glucose) could be induced by high energy diet, and these animals later developed painful polyneuropathy characterized by myelin breakdown and LMF loss in both peripheral and central nervous system. In contrast SMF and UMF in the sciatic nerves were changed little, in the same animals. Therefore the phenomenon that high energy diets induce bilateral mechanical, but not thermal, pain hypersensitivity is reflected by severe damage to LMF, but mild damage to SMF and UMF. Moreover, dietary sodium (high-salt) deteriorates the neuropathic pathological process induced by high energy diets, but paradoxically high salt consumption, may reduce, at least temporarily, chronic pain perception in these animals.
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Affiliation(s)
- Fang Xie
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, The Fourth Military Medical University, Xi'an, P. R. China
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Abstract
Experimental animals in biomedical research provide insights into disease mechanisms and models for determining the efficacy and safety of new therapies and for discovery of corresponding biomarkers. Although mouse and rat models are most widely used, observations in these species cannot always be faithfully extrapolated to human patients. Thus, a number of domestic species are additionally used in specific disease areas. This review summarizes the most important applications of domestic animal models and emphasizes the new possibilities genetic tailoring of disease models, specifically in pigs, provides.
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Affiliation(s)
- A Bähr
- Chair for Molecular Animal Breeding and Biotechnology, Department of Veterinary Sciences, Ludwig-Maximilians-Universität München, Munich, Germany
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36
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Saleh A, Schapansky J, Smith DR, Young N, Odero GL, Aulston B, Fernyhough P, Glazner GW. Normalization of NF-κB activity in dorsal root ganglia neurons cultured from diabetic rats reverses neuropathy-linked markers of cellular pathology. Exp Neurol 2012; 241:169-78. [PMID: 23159890 DOI: 10.1016/j.expneurol.2012.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 10/05/2012] [Accepted: 11/06/2012] [Indexed: 01/12/2023]
Abstract
AIMS/HYPOTHESIS Dorsal root ganglia (DRG) sensory neurons cultured from 3 to 5 month streptozotocin (STZ)-induced diabetic rats exhibit structural and biochemical changes seen in peripheral nerve fibers in vivo, including axonal swellings, oxidative damage, reduced axonal sprouting, and decreased NF-κB activity. NF-κB is a transcription factor required by DRG neurons for survival and plasticity, and regulates transcription of antioxidant proteins (e.g. MnSOD). We hypothesized that the diabetes-induced decrease in NF-κB activity in DRG contributes to pathological phenomena observed in cultured DRG neurons from diabetic rats. METHODS NF-κB localization was assessed in intact DRG and neuron cultures using immunostaining. NF-κB activity was manipulated in sensory neuron cultures derived from age-matched normal or 3-5 month STZ-diabetic rats using pharmacological means and lentiviral expression of shRNA. The impact of diabetes and altered NF-κB activity on neuronal phenotype involved analysis of neurite outgrowth, neurite morphology, oxidative stress (lipid peroxidation) and expression of MnSOD. RESULTS STZ-induced diabetes caused a significant decrease in nuclear localization of NF-κB subunits p50 and c-rel, but no change in p65 in intact DRG. Inhibition of NF-κB in normal neuron cultures significantly increased axonal swellings and oxidative stress, and reduced both neurite outgrowth and expression of MnSOD. These phenomena mimicked markers of pathology in cultured DRG neurons from diabetic rats. Enhancement of NF-κB activity in cultured diabetic DRG neurons ameliorated the sub-optimal neurite outgrowth and MnSOD levels triggered by diabetes. Exogenous insulin enhanced nuclear localization of p50 and c-rel but not p65 in diabetic neuronal cultures. CONCLUSION/INTERPRETATION The diabetes-induced decrease of nuclear localization of NF-κB subunits p50 and c-rel in DRG contributes to development of in vitro markers of peripheral neuropathy, possibly through impaired mitochondrial ROS scavenging by deficient MnSOD.
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Affiliation(s)
- A Saleh
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB, Canada
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Willmott AD, White C, Dukelow SP. Fibrillation potential onset in peripheral nerve injury. Muscle Nerve 2012; 46:332-40. [PMID: 22907222 DOI: 10.1002/mus.23310] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
INTRODUCTION Fibrillation potentials are an accepted electrical marker of muscle denervation that occur in axonal nerve injury. Clinically, they are used to determine the type of, and prognosis for nerve injuries. The time of occurrence after nerve injury plays a critical role in clinical decision making. This study explores the evolution of the generally accepted guideline that fibrillation potentials occur 1 to 4 weeks after axonal nerve injury. METHODS Pubmed, Ovid, and EMBASE, and current textbooks were reviewed. References were recursively followed back to the initial description of fibrillation potentials. RESULTS The majority of our understanding regarding the timing of onset of fibrillation potentials appears to arise from animal experiments in the mid-20th century. CONCLUSIONS Despite frequent use in human clinical care, published evidence for the 1 to 4 week guideline comes almost entirely from animal studies. An appreciation of this background and resulting limitations aids clinical application of this guideline.
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Affiliation(s)
- Andrew D Willmott
- Physical Medicine and Rehabilitation, University of Calgary, Calgary, Alberta, Canada
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Hypertension-induced peripheral neuropathy and the combined effects of hypertension and diabetes on nerve structure and function in rats. Acta Neuropathol 2012; 124:561-73. [PMID: 22791295 DOI: 10.1007/s00401-012-1012-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 06/26/2012] [Accepted: 06/29/2012] [Indexed: 01/02/2023]
Abstract
Diabetic neuropathy includes damage to neurons, Schwann cells and blood vessels. Rodent models of diabetes do not adequately replicate all pathological features of diabetic neuropathy, particularly Schwann cell damage. We, therefore, tested the hypothesis that combining hypertension, a risk factor for neuropathy in diabetic patients, with insulin-deficient diabetes produces a more pertinent model of peripheral neuropathy. Behavioral, physiological and structural indices of neuropathy were measured for up to 6 months in spontaneously hypertensive and age-matched normotensive rats with or without concurrent streptozotocin-induced diabetes. Hypertensive rats developed nerve ischemia, thermal hyperalgesia, nerve conduction slowing and axonal atrophy. Thinly myelinated fibers with supernumerary Schwann cells indicative of cycles of demyelination and remyelination were also identified along with reduced nerve levels of myelin basic protein. Similar disorders were noted in streptozotocin-diabetic rats, except that thinly myelinated fibers were not observed and expression of myelin basic protein was normal. Superimposing diabetes on hypertension compounded disorders of nerve blood flow, conduction slowing and axonal atrophy and increased the incidence of thinly myelinated fibers. Rats with combined insulinopenia, hyperglycemia and hypertension provide a model for diabetic neuropathy that offers an opportunity to study mechanisms of Schwann cell pathology and suggests that hypertension may contribute to the etiology of diabetic neuropathy.
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Rodenas S, Guo LT, Shelton GD. Myopathy associated with congenital fibre type disproportion in a young dog. J Comp Pathol 2012; 147:486-90. [PMID: 22789857 DOI: 10.1016/j.jcpa.2012.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 04/15/2012] [Accepted: 05/03/2012] [Indexed: 11/17/2022]
Abstract
A 4-month-old, female collie-cross dog was presented for evaluation of slowly progressive weakness, exercise intolerance and muscle atrophy. Neurological examination and electrodiagnostic testing were consistent with a generalized myopathy or, less likely, an axonal polyneuropathy. Muscle biopsy samples revealed marked variability in myofibre size with scattered or clustered atrophic or hypotrophic type 1 fibres. Type 1 fibres were 65% smaller than type 2A fibres and the percentage of type 1 fibres exceeded reference values for both limb muscles examined. On the basis of the clinical evaluation, pathological changes and the absence of another defined congenital or acquired myopathy, a diagnosis of a myopathy associated with congenital fibre type disproportion was made. Three months later the animal was humanely euthanized because of worsening clinical signs.
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Affiliation(s)
- S Rodenas
- Southern Counties Veterinary Specialists, Ringwood, Hampshire BH24 3JW, UK.
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40
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Shelton GD, Johnson GC, O'Brien DP, Katz ML, Pesayco JP, Chang BJ, Mizisin AP, Coates JR. Degenerative myelopathy associated with a missense mutation in the superoxide dismutase 1 (SOD1) gene progresses to peripheral neuropathy in Pembroke Welsh Corgis and Boxers. J Neurol Sci 2012; 318:55-64. [DOI: 10.1016/j.jns.2012.04.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Revised: 03/31/2012] [Accepted: 04/02/2012] [Indexed: 12/13/2022]
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Roy Chowdhury SK, Smith DR, Saleh A, Schapansky J, Marquez A, Gomes S, Akude E, Morrow D, Calcutt NA, Fernyhough P. Impaired adenosine monophosphate-activated protein kinase signalling in dorsal root ganglia neurons is linked to mitochondrial dysfunction and peripheral neuropathy in diabetes. ACTA ACUST UNITED AC 2012; 135:1751-66. [PMID: 22561641 DOI: 10.1093/brain/aws097] [Citation(s) in RCA: 161] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Mitochondrial dysfunction occurs in sensory neurons and may contribute to distal axonopathy in animal models of diabetic neuropathy. The adenosine monophosphate-activated protein kinase and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) signalling axis senses the metabolic demands of cells and regulates mitochondrial function. Studies in muscle, liver and cardiac tissues have shown that the activity of adenosine monophosphate-activated protein kinase and PGC-1α is decreased under hyperglycaemia. In this study, we tested the hypothesis that deficits in adenosine monophosphate-activated protein kinase/PGC-1α signalling in sensory neurons underlie impaired axonal plasticity, suboptimal mitochondrial function and development of neuropathy in rodent models of type 1 and type 2 diabetes. Phosphorylation and expression of adenosine monophosphate-activated protein kinase/PGC-1α and mitochondrial respiratory chain complex proteins were downregulated in dorsal root ganglia of both streptozotocin-diabetic rats and db/db mice. Adenoviral-mediated manipulation of endogenous adenosine monophosphate-activated protein kinase activity using mutant proteins modulated neurotrophin-directed neurite outgrowth in cultures of sensory neurons derived from adult rats. Addition of resveratrol to cultures of sensory neurons derived from rats after 3-5 months of streptozotocin-induced diabetes, significantly elevated adenosine monophosphate-activated protein kinase levels, enhanced neurite outgrowth and normalized mitochondrial inner membrane polarization in axons. The bioenergetics profile (maximal oxygen consumption rate, coupling efficiency, respiratory control ratio and spare respiratory capacity) was aberrant in cultured sensory neurons from streptozotocin-diabetic rats and was corrected by resveratrol treatment. Finally, resveratrol treatment for the last 2 months of a 5-month period of diabetes reversed thermal hypoalgesia and attenuated foot skin intraepidermal nerve fibre loss and reduced myelinated fibre mean axonal calibre in streptozotocin-diabetic rats. These data suggest that the development of distal axonopathy in diabetic neuropathy is linked to nutrient excess and mitochondrial dysfunction via defective signalling of the adenosine monophosphate-activated protein kinase/PGC-1α pathway.
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Affiliation(s)
- Subir K Roy Chowdhury
- Division of Neurodegenerative Disorders, St. Boniface Hospital Research Centre, R4023-1 - 351 Tache Avenue, Winnipeg, MB R2H 2A6, Canada.
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Chowdhury SKR, Smith DR, Fernyhough P. The role of aberrant mitochondrial bioenergetics in diabetic neuropathy. Neurobiol Dis 2012; 51:56-65. [PMID: 22446165 DOI: 10.1016/j.nbd.2012.03.016] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 02/22/2012] [Accepted: 03/01/2012] [Indexed: 02/07/2023] Open
Abstract
Diabetic neuropathy is a neurological complication of diabetes that causes significant morbidity and, because of the obesity-driven rise in incidence of type 2 diabetes, is becoming a major international health problem. Mitochondrial phenotype is abnormal in sensory neurons in diabetes and may contribute to the etiology of diabetic neuropathy where a distal dying-back neurodegenerative process is a key component contributing to fiber loss. This review summarizes the major features of mitochondrial dysfunction in neurons and Schwann cells in human diabetic patients and in experimental animal models (primarily exhibiting type 1 diabetes). This article attempts to relate these findings to the development of critical neuropathological hallmarks of the disease. Recent work reveals that hyperglycemia in diabetes triggers nutrient excess in neurons that, in turn, mediates a phenotypic change in mitochondrial biology through alteration of the AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) signaling axis. This vital energy sensing metabolic pathway modulates mitochondrial function, biogenesis and regeneration. The bioenergetic phenotype of mitochondria in diabetic neurons is aberrant due to deleterious alterations in expression and activity of respiratory chain components as a direct consequence of abnormal AMPK/PGC-1α signaling. Utilization of innovative respirometry equipment to analyze mitochondrial function of cultured adult sensory neurons from diabetic rodents shows that the outcome for cellular bioenergetics is a reduced adaptability to fluctuations in ATP demand. The diabetes-induced maladaptive process is hypothesized to result in exhaustion of the ATP supply in the distal nerve compartment and induction of nerve fiber dissolution. The role of mitochondrial dysfunction in the etiology of diabetic neuropathy is compared with other types of neuropathy with a distal dying-back pathology such as Friedreich ataxia, Charcot-Marie-Tooth disease type 2 and human immunodeficiency virus-associated distal-symmetric neuropathy.
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Affiliation(s)
- Subir K Roy Chowdhury
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB, Canada
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Sensory neurons derived from diabetic rats have diminished internal Ca2+ stores linked to impaired re-uptake by the endoplasmic reticulum. ASN Neuro 2012; 4:AN20110038. [PMID: 22168362 PMCID: PMC3260471 DOI: 10.1042/an20110038] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Distal symmetrical sensory neuropathy in diabetes involves the dying back of axons, and the pathology equates with axonal dystrophy generated under conditions of aberrant Ca2+ signalling. Previous work has described abnormalities in Ca2+ homoeostasis in sensory and dorsal horn neurons acutely isolated from diabetic rodents. We extended this work by testing the hypothesis that sensory neurons exposed to long-term Type 1 diabetes in vivo would exhibit abnormal axonal Ca2+ homoeostasis and focused on the role of SERCA (sarcoplasmic/endoplasmic reticulum Ca2+-ATPase). DRG (dorsal root ganglia) sensory neurons from age-matched normal and 3-5-month-old STZ (streptozotocin)-diabetic rats (an experimental model of Type 1 diabetes) were cultured. At 1-2 days in vitro an array of parameters were measured to investigate Ca2+ homoeostasis including (i) axonal levels of intracellular Ca2+, (ii) Ca2+ uptake by the ER (endoplasmic reticulum), (iii) assessment of Ca2+ signalling following a long-term thapsigargin-induced blockade of SERCA and (iv) determination of expression of ER mass and stress markers using immunocytochemistry and Western blotting. KCl- and caffeine-induced Ca2+ transients in axons were 2-fold lower in cultures of diabetic neurons compared with normal neurons indicative of reduced ER calcium loading. The rate of uptake of Ca2+ into the ER was reduced by 2-fold (P<0.05) in diabetic neurons, while markers for ER mass and ER stress were unchanged. Abnormalities in Ca2+ homoeostasis in diabetic neurons could be mimicked via long-term inhibition of SERCA in normal neurons. In summary, axons of neurons from diabetic rats exhibited aberrant Ca2+ homoeostasis possibly triggered by sub-optimal SERCA activity that could contribute to the distal axonopathy observed in diabetes.
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Beirowski B, Gustin J, Armour SM, Yamamoto H, Viader A, North BJ, Michán S, Baloh RH, Golden JP, Schmidt RE, Sinclair DA, Auwerx J, Milbrandt J. Sir-two-homolog 2 (Sirt2) modulates peripheral myelination through polarity protein Par-3/atypical protein kinase C (aPKC) signaling. Proc Natl Acad Sci U S A 2011; 108:E952-61. [PMID: 21949390 PMCID: PMC3203793 DOI: 10.1073/pnas.1104969108] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The formation of myelin by Schwann cells (SCs) occurs via a series of orchestrated molecular events. We previously used global expression profiling to examine peripheral nerve myelination and identified the NAD(+)-dependent deacetylase Sir-two-homolog 2 (Sirt2) as a protein likely to be involved in myelination. Here, we show that Sirt2 expression in SCs is correlated with that of structural myelin components during both developmental myelination and remyelination after nerve injury. Transgenic mice lacking or overexpressing Sirt2 specifically in SCs show delays in myelin formation. In SCs, we found that Sirt2 deacetylates Par-3, a master regulator of cell polarity. The deacetylation of Par-3 by Sirt2 decreases the activity of the polarity complex signaling component aPKC, thereby regulating myelin formation. These results demonstrate that Sirt2 controls an essential polarity pathway in SCs during myelin assembly and provide insights into the association between intracellular metabolism and SC plasticity.
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Affiliation(s)
| | - Jason Gustin
- Sigma–Aldrich Biotechnology, St. Louis, MO 63103
| | - Sean M. Armour
- Department of Pathology, Harvard University School of Medicine, Cambridge, MA 02115
| | - Hiroyasu Yamamoto
- Laboratory for Integrative and Systems Physiology, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | | | - Brian J. North
- Department of Pathology, Harvard University School of Medicine, Cambridge, MA 02115
| | - Shaday Michán
- Instituto de Geriatria, Institutos Nacionales de Salud, Mexico D.F., 04510, Mexico
| | - Robert H. Baloh
- Neurology, and
- Hope Center for Neurological Diseases, St. Louis, MO 63110; and
| | - Judy P. Golden
- Department of Anesthesiology, Washington University Pain Center, St. Louis, MO 63110
| | - Robert E. Schmidt
- Pathology, Washington University School of Medicine, St. Louis, MO 63110
- Hope Center for Neurological Diseases, St. Louis, MO 63110; and
| | - David A. Sinclair
- Department of Pathology, Harvard University School of Medicine, Cambridge, MA 02115
| | - Johan Auwerx
- Laboratory for Integrative and Systems Physiology, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Jeffrey Milbrandt
- Departments of Genetics
- Hope Center for Neurological Diseases, St. Louis, MO 63110; and
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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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Foss K, da Costa R, Wolk K, Stromberg P, Guo L, Shelton G. Multisystem Cranial Polyneuritis and Ganglionitis in a Dog. J Vet Intern Med 2011; 25:1161-5. [DOI: 10.1111/j.1939-1676.2011.0764.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Chowdhury SKR, Dobrowsky RT, Fernyhough P. Nutrient excess and altered mitochondrial proteome and function contribute to neurodegeneration in diabetes. Mitochondrion 2011; 11:845-54. [PMID: 21742060 DOI: 10.1016/j.mito.2011.06.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 04/28/2011] [Accepted: 06/24/2011] [Indexed: 01/01/2023]
Abstract
Diabetic neuropathy is a major complication of diabetes that results in the progressive deterioration of the sensory nervous system. Mitochondrial dysfunction has been proposed to play an important role in the pathogenesis of the neurodegeneration observed in diabetic neuropathy. Our recent work has shown that mitochondrial dysfunction occurs in dorsal root ganglia (DRG) sensory neurons in streptozotocin (STZ) induced diabetic rodents. In neurons, the nutrient excess associated with prolonged diabetes may trigger a switching off of AMP kinase (AMPK) and/or silent information regulator T1 (SIRT1) signaling leading to impaired peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1α) expression/activity and diminished mitochondrial activity. This review briefly summarizes the alterations of mitochondrial function and proteome in sensory neurons of STZ-diabetic rodents. We also discuss the possible involvement of AMPK/SIRT/PGC-1α pathway in other diabetic models and different tissues affected by diabetes.
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Affiliation(s)
- Subir K Roy Chowdhury
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB, Canada R2H 2A6
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Bensfield A, Evans J, Pesayco J, Mizisin A, Shelton G. Recurrent Demyelination and Remyelination in 37 Young Bengal Cats with Polyneuropathy. J Vet Intern Med 2011; 25:882-9. [DOI: 10.1111/j.1939-1676.2011.0740.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Thieman KM, Krahwinkel DJ, Sims MH, Shelton GD. Histopathological confirmation of polyneuropathy in 11 dogs with laryngeal paralysis. J Am Anim Hosp Assoc 2010; 46:161-7. [PMID: 20439938 DOI: 10.5326/0460161] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Acquired laryngeal paralysis (LP) is an important cause of upper airway obstruction in dogs. We hypothesize that LP may be part of a generalized polyneuropathy complex. Electro-diagnostic studies were performed in six dogs, and histopathological studies of muscle and nerve biopsies were obtained from 11 dogs diagnosed with acquired LP. Abnormalities in electrodiagnostic procedures were consistent with a generalized polyneuropathy. Loss of large-caliber nerve fibers and axonal degeneration were identified in nerve biopsies, and neurogenic atrophy was observed in muscle specimens. Abnormalities in electrodiagnostic studies and histopathology provide evidence that LP may be part of a generalized polyneuropathy. Establishing a diagnosis of a more involved disease process is relevant for long-term prognosis.
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Affiliation(s)
- Kelley M Thieman
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, The University of Tennessee, 2407 River Drive, Knoxville, Tennessee 37996, USA
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Abstract
PRACTICAL RELEVANCE Long-term pain in cats is an important welfare issue but is often overlooked and undertreated. AUDIENCE All practitioners are faced with cats that require analgesic intervention to improve their quality of life. PATIENT GROUP Any cat may potentially experience long-term pain and discomfort. Degenerative joint disease and diabetic-related pain is more common in middle-aged or older individuals, whereas persistent postsurgical pain can occur at any age and is seen in young cats following onychectomy. EVIDENCE BASE Robust evidence on long-term pain issues in cats - specifically, relating to prevalence, etiology, and treatment protocols and outcomes - is missing from the veterinary literature. The aim of this review is to summarise the current state of knowledge. In doing so, it takes a practical approach, highlighting the obvious, and some not so obvious, causes of long-term pain in cats; some aspects that warrant closer attention; our ability to recognize pain and monitor how this impacts on quality of life; and today's treatment options.
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