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Casselini CM, Parson HK, Frizzi KE, Marquez A, Smith DR, Guernsey L, Nemmani R, Tayarani A, Jolivalt CG, Weaver J, Fernyhough P, Vinik AI, Calcutt NA. A muscarinic receptor antagonist reverses multiple indices of diabetic peripheral neuropathy: preclinical and clinical studies using oxybutynin. Acta Neuropathol 2024; 147:60. [PMID: 38526612 DOI: 10.1007/s00401-024-02710-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/16/2024] [Accepted: 02/17/2024] [Indexed: 03/27/2024]
Abstract
Preclinical studies indicate that diverse muscarinic receptor antagonists, acting via the M1 sub-type, promote neuritogenesis from sensory neurons in vitro and prevent and/or reverse both structural and functional indices of neuropathy in rodent models of diabetes. We sought to translate this as a potential therapeutic approach against structural and functional indices of diabetic neuropathy using oxybutynin, a muscarinic antagonist approved for clinical use against overactive bladder. Studies were performed using sensory neurons maintained in vitro, rodent models of type 1 or type 2 diabetes and human subjects with type 2 diabetes and confirmed neuropathy. Oxybutynin promoted significant neurite outgrowth in sensory neuron cultures derived from adult normal rats and STZ-diabetic mice, with maximal efficacy in the 1-100 nmol/l range. This was accompanied by a significantly enhanced mitochondrial energetic profile as reflected by increased basal and maximal respiration and spare respiratory capacity. Systemic (3-10 mg/kg/day s.c.) and topical (3% gel daily) oxybutynin reversed paw heat hypoalgesia in the STZ and db/db mouse models of diabetes and reversed paw tactile allodynia in STZ-diabetic rats. Loss of nerve profiles in the skin and cornea of db/db mice was also prevented by daily topical delivery of 3% oxybutynin for 8 weeks. A randomized, double-blind, placebo-controlled interventional trial was performed in subjects with type 2 diabetes and established peripheral neuropathy. Subjects received daily topical treatment with 3% oxybutynin gel or placebo for 6 months. The a priori designated primary endpoint, significant change in intra-epidermal nerve fibre density (IENFD) in skin biopsies taken before and after 20 weeks of treatments, was met by oxybutynin but not placebo. Secondary endpoints showing significant improvement with oxybutynin treatment included scores on clinical neuropathy, pain and quality of life scales. This proof-of-concept study indicates that muscarinic antagonists suitable for long-term use may offer a novel therapeutic opportunity for treatment of diabetic neuropathy. Trial registry number: NCT03050827.
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Affiliation(s)
- Carolina M Casselini
- Department of Internal Medicine, Strelitz Diabetes Center, Endocrine and Metabolic Disorders, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Henri K Parson
- Department of Internal Medicine, Strelitz Diabetes Center, Endocrine and Metabolic Disorders, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Katie E Frizzi
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Alex Marquez
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Darrell R Smith
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, R4046 - 351 Taché Ave, Winnipeg, MB, R2H 2A6, Canada
| | - Lucie Guernsey
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Rakesh Nemmani
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Alireza Tayarani
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Corinne G Jolivalt
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Jessica Weaver
- Department of Internal Medicine, Strelitz Diabetes Center, Endocrine and Metabolic Disorders, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, R4046 - 351 Taché Ave, Winnipeg, MB, R2H 2A6, Canada
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB, Canada
| | - Aaron I Vinik
- Department of Internal Medicine, Strelitz Diabetes Center, Endocrine and Metabolic Disorders, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Nigel A Calcutt
- Department of Pathology, University of California San Diego, La Jolla, CA, USA.
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2
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Simon Machado R, Mathias K, Joaquim L, Willig de Quadros R, Petronilho F, Tezza Rezin G. From diabetic hyperglycemia to cerebrovascular Damage: A narrative review. Brain Res 2023; 1821:148611. [PMID: 37793604 DOI: 10.1016/j.brainres.2023.148611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/04/2023] [Accepted: 09/28/2023] [Indexed: 10/06/2023]
Abstract
Diabetes mellitus is a globally significant disease that can lead to systemic complications, particularly vascular damage, including cardiovascular and cerebrovascular diseases of relevance. The physiological changes resulting from the imbalance in blood glucose levels play a crucial role in initiating vascular endothelial damage. Elevated glucose levels can also penetrate the central nervous system, triggering diabetic encephalopathy characterized by oxidative damage to brain components and activation of alternative and neurotoxic pathways. This brain damage increases the risk of ischemic stroke, a leading cause of mortality worldwide and a major cause of disability among surviving patients. The aim of this review is to highlight important pathways related to hyperglycemic damage that extend to the brain and result in vascular dysfunction, ultimately leading to the occurrence of a stroke. Understanding how diabetes mellitus contributes to the development of ischemic stroke and its impact on patient outcomes is crucial for implementing therapeutic strategies that reduce the incidence of diabetes mellitus and its complications, ultimately decreasing morbidity and mortality associated with the disease.
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Affiliation(s)
- Richard Simon Machado
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil; Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil.
| | - Khiany Mathias
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil
| | - Larissa Joaquim
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil
| | - Rafaella Willig de Quadros
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil
| | - Fabricia Petronilho
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil
| | - Gislaine Tezza Rezin
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
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3
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Handzlik MK, Gengatharan JM, Frizzi KE, McGregor GH, Martino C, Rahman G, Gonzalez A, Moreno AM, Green CR, Guernsey LS, Lin T, Tseng P, Ideguchi Y, Fallon RJ, Chaix A, Panda S, Mali P, Wallace M, Knight R, Gantner ML, Calcutt NA, Metallo CM. Insulin-regulated serine and lipid metabolism drive peripheral neuropathy. Nature 2023; 614:118-124. [PMID: 36697822 PMCID: PMC9891999 DOI: 10.1038/s41586-022-05637-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 12/07/2022] [Indexed: 01/26/2023]
Abstract
Diabetes represents a spectrum of disease in which metabolic dysfunction damages multiple organ systems including liver, kidneys and peripheral nerves1,2. Although the onset and progression of these co-morbidities are linked with insulin resistance, hyperglycaemia and dyslipidaemia3-7, aberrant non-essential amino acid (NEAA) metabolism also contributes to the pathogenesis of diabetes8-10. Serine and glycine are closely related NEAAs whose levels are consistently reduced in patients with metabolic syndrome10-14, but the mechanistic drivers and downstream consequences of this metabotype remain unclear. Low systemic serine and glycine are also emerging as a hallmark of macular and peripheral nerve disorders, correlating with impaired visual acuity and peripheral neuropathy15,16. Here we demonstrate that aberrant serine homeostasis drives serine and glycine deficiencies in diabetic mice, which can be diagnosed with a serine tolerance test that quantifies serine uptake and disposal. Mimicking these metabolic alterations in young mice by dietary serine or glycine restriction together with high fat intake markedly accelerates the onset of small fibre neuropathy while reducing adiposity. Normalization of serine by dietary supplementation and mitigation of dyslipidaemia with myriocin both alleviate neuropathy in diabetic mice, linking serine-associated peripheral neuropathy to sphingolipid metabolism. These findings identify systemic serine deficiency and dyslipidaemia as novel risk factors for peripheral neuropathy that may be exploited therapeutically.
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Affiliation(s)
- Michal K Handzlik
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Jivani M Gengatharan
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Katie E Frizzi
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Grace H McGregor
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Cameron Martino
- Department of Pediatrics, School of Medicine, University of California San Diego, La Jolla, CA, USA
- Bioinformatics and Systems Biology Program, University of California San Diego, La Jolla, CA, USA
- Center for Microbiome Innovation, University of California San Diego, La Jolla, CA, USA
| | - Gibraan Rahman
- Department of Pediatrics, School of Medicine, University of California San Diego, La Jolla, CA, USA
- Bioinformatics and Systems Biology Program, University of California San Diego, La Jolla, CA, USA
| | - Antonio Gonzalez
- Department of Pediatrics, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Ana M Moreno
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Courtney R Green
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Lucie S Guernsey
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Terry Lin
- Regulatory Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Patrick Tseng
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | | | | | - Amandine Chaix
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Satchidananda Panda
- Regulatory Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Prashant Mali
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Martina Wallace
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Rob Knight
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
- Department of Pediatrics, School of Medicine, University of California San Diego, La Jolla, CA, USA
- Bioinformatics and Systems Biology Program, University of California San Diego, La Jolla, CA, USA
- Center for Microbiome Innovation, University of California San Diego, La Jolla, CA, USA
| | | | - Nigel A Calcutt
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Christian M Metallo
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA.
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA.
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Ponirakis G, Abdul‐Ghani MA, Jayyousi A, Zirie MA, Al‐Mohannadi S, Almuhannadi H, Petropoulos IN, Khan A, Gad H, Migahid O, Megahed A, Qazi M, AlMarri F, Al‐Khayat F, Mahfoud Z, DeFronzo R, Malik RA. Insulin resistance limits corneal nerve regeneration in patients with type 2 diabetes undergoing intensive glycemic control. J Diabetes Investig 2021; 12:2002-2009. [PMID: 34002953 PMCID: PMC8565403 DOI: 10.1111/jdi.13582] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 03/22/2021] [Accepted: 04/15/2021] [Indexed: 01/04/2023] Open
Abstract
AIMS/INTRODUCTION This study aimed to investigate whether insulin resistance (IR) in individuals with type 2 diabetes undergoing intensive glycemic control determines the extent of improvement in neuropathy. MATERIALS AND METHODS This was an exploratory substudy of an open-label, randomized controlled trial of individuals with poorly controlled type 2 diabetes treated with exenatide and pioglitazone or insulin to achieve a glycated hemoglobin <7.0% (<53 mmol/mol). Baseline IR was defined using homeostasis model assessment of IR, and change in neuropathy was assessed using corneal confocal microscopy. RESULTS A total of 38 individuals with type 2 diabetes aged 50.2 ± 8.5 years with (n = 25, 66%) and without (n = 13, 34%) IR were studied. There was a significant decrease in glycated hemoglobin (P < 0.0001), diastolic blood pressure (P < 0.0001), total cholesterol (P < 0.01) and low-density lipoprotein (P = 0.05), and an increase in bodyweight (P < 0.0001) with treatment. Individuals with homeostasis model assessment of IR <1.9 showed a significant increase in corneal nerve fiber density (P ≤ 0.01), length (P ≤ 0.01) and branch density (P ≤ 0.01), whereas individuals with homeostasis model assessment of IR ≥1.9 showed no change. IR was negatively associated with change in corneal nerve fiber density after adjusting for change in bodyweight (P < 0.05). CONCLUSIONS Nerve regeneration might be limited in individuals with type 2 diabetes and IR undergoing treatment with pioglitazone plus exenatide or insulin to improve glycemic control.
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Affiliation(s)
- Georgios Ponirakis
- Weill Cornell Medicine in QatarQatar FoundationEducation City, DohaQatar
- Faculty of Science and EngineeringManchester Metropolitan UniversityManchesterUK
| | - Muhammad A Abdul‐Ghani
- National Diabetes CenterHamad General HospitalHamad Medical CorporationDohaQatar
- Division of DiabetesUniversity of Texas Health Science CenterSan AntonioTexasUSA
| | - Amin Jayyousi
- National Diabetes CenterHamad General HospitalHamad Medical CorporationDohaQatar
| | - Mahmoud A Zirie
- National Diabetes CenterHamad General HospitalHamad Medical CorporationDohaQatar
| | - Salma Al‐Mohannadi
- Weill Cornell Medicine in QatarQatar FoundationEducation City, DohaQatar
| | - Hamad Almuhannadi
- Weill Cornell Medicine in QatarQatar FoundationEducation City, DohaQatar
| | | | - Adnan Khan
- Weill Cornell Medicine in QatarQatar FoundationEducation City, DohaQatar
| | - Hoda Gad
- Weill Cornell Medicine in QatarQatar FoundationEducation City, DohaQatar
| | - Osama Migahid
- National Diabetes CenterHamad General HospitalHamad Medical CorporationDohaQatar
- Division of DiabetesUniversity of Texas Health Science CenterSan AntonioTexasUSA
| | - Ayman Megahed
- National Diabetes CenterHamad General HospitalHamad Medical CorporationDohaQatar
| | - Murtaza Qazi
- Weill Cornell Medicine in QatarQatar FoundationEducation City, DohaQatar
| | - Fatema AlMarri
- Weill Cornell Medicine in QatarQatar FoundationEducation City, DohaQatar
| | - Fatima Al‐Khayat
- Weill Cornell Medicine in QatarQatar FoundationEducation City, DohaQatar
| | - Ziyad Mahfoud
- Weill Cornell Medicine in QatarQatar FoundationEducation City, DohaQatar
| | - Ralph DeFronzo
- Division of DiabetesUniversity of Texas Health Science CenterSan AntonioTexasUSA
| | - Rayaz A Malik
- Weill Cornell Medicine in QatarQatar FoundationEducation City, DohaQatar
- Faculty of Science and EngineeringManchester Metropolitan UniversityManchesterUK
- National Diabetes CenterHamad General HospitalHamad Medical CorporationDohaQatar
- Institute of Cardiovascular ScienceUniversity of ManchesterManchesterUK
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5
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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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6
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Dabbara H, Schultz A, Im SH. Drosophila insulin receptor regulates diabetes-induced mechanical nociceptive hypersensitivity. MICROPUBLICATION BIOLOGY 2021; 2021. [PMID: 34549177 PMCID: PMC8449261 DOI: 10.17912/micropub.biology.000456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/31/2021] [Accepted: 09/01/2021] [Indexed: 11/17/2022]
Abstract
Painful diabetic neuropathy (PDN) is one of the predominant complications of diabetes that causes numbness, tingling, and extreme pain sensitivity. Understanding the mechanisms of PDN pathogenesis is important for patient treatments. Here we report Drosophila models of diabetes-induced mechanical nociceptive hypersensitivity. Type 2 diabetes-like conditions and loss of insulin receptor function in multidendritic sensory neurons lead to mechanical nociceptive hypersensitivity. Furthermore, we also found that restoring insulin signaling in multidendritic sensory neurons can block diabetes-induced mechanical nociceptive hypersensitivity. Our work highlights the critical role of insulin signaling in nociceptive sensory neurons in the regulation of diabetes-induced nociceptive hypersensitivities.
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Affiliation(s)
| | | | - Seol Hee Im
- Department of Biology, Haverford College, Haverford, PA
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7
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Felicetti G, Thoumie P, Do MC, Schieppati M. Cutaneous and muscular afferents from the foot and sensory fusion processing: Physiology and pathology in neuropathies. J Peripher Nerv Syst 2021; 26:17-34. [PMID: 33426723 DOI: 10.1111/jns.12429] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/30/2020] [Accepted: 12/30/2020] [Indexed: 12/16/2022]
Abstract
The foot-sole cutaneous receptors (section 2), their function in stance control (sway minimisation, exploratory role) (2.1), and the modulation of their effects by gait pattern and intended behaviour (2.2) are reviewed. Experimental manipulations (anaesthesia, temperature) (2.3 and 2.4) have shown that information from foot sole has widespread influence on balance. Foot-sole stimulation (2.5) appears to be a promising approach for rehabilitation. Proprioceptive information (3) has a pre-eminent role in balance and gait. Reflex responses to balance perturbations are produced by both leg and foot muscle stretch (3.1) and show complex interactions with skin input at both spinal and supra-spinal levels (3.2), where sensory feedback is modulated by posture, locomotion and vision. Other muscles, notably of neck and trunk, contribute to kinaesthesia and sense of orientation in space (3.3). The effects of age-related decline of afferent input are variable under different foot-contact and visual conditions (3.4). Muscle force diminishes with age and sarcopenia, affecting intrinsic foot muscles relaying relevant feedback (3.5). In neuropathy (4), reduction in cutaneous sensation accompanies the diminished density of viable receptors (4.1). Loss of foot-sole input goes along with large-fibre dysfunction in intrinsic foot muscles. Diabetic patients have an elevated risk of falling, and vision and vestibular compensation strategies may be inadequate (4.2). From Charcot-Marie-Tooth 1A disease (4.3) we have become aware of the role of spindle group II fibres and of the anatomical feet conditions in balance control. Lastly (5) we touch on the effects of nerve stimulation onto cortical and spinal excitability, which may participate in plasticity processes, and on exercise interventions to reduce the impact of neuropathy.
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Affiliation(s)
- Guido Felicetti
- Istituti Clinici Scientifici Maugeri IRCCS, Unit of Neuromotor Rehabilitation, Institute of Montescano, Pavia, Italy
| | - Philippe Thoumie
- Service de rééducation neuro-orthopédique, Hôpital Rothschild APHP, Université Sorbonne, Paris, France.,Agathe Lab ERL Inserm U-1150, Paris, France
| | - Manh-Cuong Do
- Université Paris-Saclay, CIAMS, Orsay, France.,Université d'Orléans, CIAMS, Orléans, France
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8
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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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Mizukami H, Osonoi S, Takaku S, Yamagishi SI, Ogasawara S, Sango K, Chung S, Yagihashi S. Role of glucosamine in development of diabetic neuropathy independent of the aldose reductase pathway. Brain Commun 2020; 2:fcaa168. [PMID: 33305258 PMCID: PMC7713992 DOI: 10.1093/braincomms/fcaa168] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 08/04/2020] [Accepted: 08/24/2020] [Indexed: 12/30/2022] Open
Abstract
Long-term metabolic aberrations contribute to the development of diabetic neuropathy but the precise mechanism or mechanisms remains elusive. We have previously shown that aldose reductase-deficient mice exhibit delayed onset and progression of neuropathy following induction of diabetes, suggesting a role both for downstream metabolites of this enzyme and also for other unrelated pathways. In this study, we have utilized comprehensive metabolomics analyses to identify potential neurotoxic metabolites in nerve of diabetic mice and explored the mechanism of peripheral nerve injury. Aldose reductase knockout and control C57Bl/6J mice were made diabetic by injection of streptozotocin and followed for 8–16 weeks. Diabetic aldose reductase knockout mice exhibited delayed onset of nerve conduction slowing compared to diabetic wild-type mice. The sciatic nerves from aldose reductase knockout mice exposed to 12 weeks of diabetes were used for metabolomics analysis and compared with analyses of nerves from age-matched diabetic wild-type mice as well as non-diabetic aldose reductase knockout and wild-type mice. Neurotoxicity of candidate metabolites was evaluated using cultured Schwann cells and dorsal root ganglion neurons, and further confirmed in vivo. Metabolomics analysis identified elevated glucosamine levels in both diabetic aldose reductase knockout and diabetic wild mice. Exposure to glucosamine reduced survival of cultured Schwann cells and neurons accompanied by increased expression of cleaved caspase 3, CCAT-enhancer-binding homologous protein and mitochondrial hexokinase-I, along with ATP depletion. These changes were suppressed by siRNA to hexokinase-I or the ATP donor, inosine, but not by the antioxidant N-acetylcysteine or the endoplasmic reticulum-stress inhibitor 4-phenylbutyrate. The O-GlcNAcylation enhancer, O-(2-acetamido-2-deoxy-d-glucopyranosylidene) amino N-phenylcarbamate, did not augment glucosamine neurotoxicity. Single dose glucosamine injection into mice caused a reduction of sciatic nerve Na, K-ATPase activity, ATP content and augmented expression of hexokinase-I, which were suppressed by pretreatment with inosine but not with 4-phenylbutyrate. Mice implanted with a subcutaneous pump to infuse glucosamine for 12 weeks developed nerve conduction slowing and intraepidermal nerve fibre loss, recapitulating prominent indices of diabetic neuropathy. While acute glucosamine neurotoxicity is unlikely to contribute substantially to the slowly developing neuropathy phenotype in humans, sustained energy deprivation induced by glucosamine may well contribute to the pathogenesis of diabetic neuropathy. Our data thus identifies a novel pathway for diabetic neuropathy that may offer a potential new therapeutic target.
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Affiliation(s)
- Hiroki Mizukami
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Sho Osonoi
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Shizuka Takaku
- Diabetic Neuropathy Project, Tokyo Metropolitan Institute of Medical Science, Tokyo
| | - Shin-Ichiro Yamagishi
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Saori Ogasawara
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Kazunori Sango
- Diabetic Neuropathy Project, Tokyo Metropolitan Institute of Medical Science, Tokyo
| | - Sookja Chung
- Faculty of Medicine, Macau University of Science and Technology, Taipa, Macau
| | - Soroku Yagihashi
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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10
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Abstract
PURPOSE OF REVIEW The current review addresses one of the most common neurological disorders, diabetic polyneuropathy (DPN). DPN is debilitating, irreversible and dwarfs the prevalence of most other chronic disorders of the nervous system. Its complications include foot ulceration, amputation, falling and intractable neuropathic pain. Moreover, tight control of hyperglycemia reduces the incidence of DPN in type 1 diabetes mellitus but its role in type 2 diabetes mellitus is less clear. RECENT FINDINGS New therapeutic options to reverse the development of DPN or its associated pain have been proposed but none have significantly changed the clinical approach. The cause of DPN remains controversial traditionally focused on the impact of metabolic abnormalities, polyol flux, microvascular changes, mitochondria, oxidative stress, lipid biology and others. In particular, there has been less attention toward how this chronic disorder alters peripheral neurobiology. It is now clear that in chronic models of diabetes mellitus there exists a unique form of neurodegeneration with a range of protein, mRNA and microRNA alterations to consider. How to reconcile these molecular and structural alterations with metabolic mechanisms is a challenge. In sensory neurons alone, a primary target of DPN, both central perikaryal cytoplasmic and nuclear changes and altered distal sensory axon terminal plasticity may be involved. SUMMARY In this review, the current therapeutic status of DPN is described with greater emphasis on some new but selected thoughts on its neurobiology. New mechanistic understanding will be essential to developing precision therapeutics for DPN.
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Lázár BA, Jancsó G, Sántha P. Modulation of Sensory Nerve Function by Insulin: Possible Relevance to Pain, Inflammation and Axon Growth. Int J Mol Sci 2020; 21:E2507. [PMID: 32260335 PMCID: PMC7177741 DOI: 10.3390/ijms21072507] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 12/16/2022] Open
Abstract
Insulin, besides its pivotal role in energy metabolism, may also modulate neuronal processes through acting on insulin receptors (InsRs) expressed by neurons of both the central and the peripheral nervous system. Recently, the distribution and functional significance of InsRs localized on a subset of multifunctional primary sensory neurons (PSNs) have been revealed. Systematic investigations into the cellular electrophysiology, neurochemistry and morphological traits of InsR-expressing PSNs indicated complex functional interactions among specific ion channels, proteins and neuropeptides localized in these neurons. Quantitative immunohistochemical studies have revealed disparate localization of the InsRs in somatic and visceral PSNs with a dominance of InsR-positive neurons innervating visceral organs. These findings suggested that visceral spinal PSNs involved in nociceptive and inflammatory processes are more prone to the modulatory effects of insulin than somatic PSNs. Co-localization of the InsR and transient receptor potential vanilloid 1 (TRPV1) receptor with vasoactive neuropeptides calcitonin gene-related peptide and substance P bears of crucial importance in the pathogenesis of inflammatory pathologies affecting visceral organs, such as the pancreas and the urinary bladder. Recent studies have also revealed significant novel aspects of the neurotrophic propensities of insulin with respect to axonal growth, development and regeneration.
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Affiliation(s)
| | - Gábor Jancsó
- Department of Physiology, University of Szeged, H-6720 Szeged, Hungary; (G.J.); (P.S.)
| | - Péter Sántha
- Department of Physiology, University of Szeged, H-6720 Szeged, Hungary; (G.J.); (P.S.)
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12
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Muscarinic Toxin 7 Signals Via Ca 2+/Calmodulin-Dependent Protein Kinase Kinase β to Augment Mitochondrial Function and Prevent Neurodegeneration. Mol Neurobiol 2020; 57:2521-2538. [PMID: 32198698 PMCID: PMC7253379 DOI: 10.1007/s12035-020-01900-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 03/09/2020] [Indexed: 12/29/2022]
Abstract
Mitochondrial dysfunction is implicated in a variety of neurodegenerative diseases of the nervous system. Peroxisome proliferator–activated receptor-γ coactivator-1α (PGC-1α) is a regulator of mitochondrial function in multiple cell types. In sensory neurons, AMP-activated protein kinase (AMPK) augments PGC-1α activity and this pathway is depressed in diabetes leading to mitochondrial dysfunction and neurodegeneration. Antimuscarinic drugs targeting the muscarinic acetylcholine type 1 receptor (M1R) prevent/reverse neurodegeneration by inducing nerve regeneration in rodent models of diabetes and chemotherapy-induced peripheral neuropathy (CIPN). Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ) is an upstream regulator of AMPK activity. We hypothesized that antimuscarinic drugs modulate CaMKKβ to enhance activity of AMPK, and PGC-1α, increase mitochondrial function and thus protect from neurodegeneration. We used the specific M1R antagonist muscarinic toxin 7 (MT7) to manipulate muscarinic signaling in the dorsal root ganglia (DRG) neurons of normal rats or rats with streptozotocin-induced diabetes. DRG neurons treated with MT7 (100 nM) or a selective muscarinic antagonist, pirenzepine (1 μM), for 24 h showed increased neurite outgrowth that was blocked by the CaMKK inhibitor STO-609 (1 μM) or short hairpin RNA to CaMKKβ. MT7 enhanced AMPK phosphorylation which was blocked by STO-609 (1 μM). PGC-1α reporter activity was augmented up to 2-fold (p < 0.05) by MT7 and blocked by STO-609. Mitochondrial maximal respiration and spare respiratory capacity were elevated after 3 h of exposure to MT7 (p < 0.05). Diabetes and CIPN induced a significant (p < 0.05) decrease in corneal nerve density which was corrected by topical delivery of MT7. We reveal a novel M1R-modulated, CaMKKβ-dependent pathway in neurons that represents a therapeutic target to enhance nerve repair in two of the most common forms of peripheral neuropathy.
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Jolivalt CG, Marquez A, Quach D, Navarro Diaz MC, Anaya C, Kifle B, Muttalib N, Sanchez G, Guernsey L, Hefferan M, Smith DR, Fernyhough P, Johe K, Calcutt NA. Amelioration of Both Central and Peripheral Neuropathy in Mouse Models of Type 1 and Type 2 Diabetes by the Neurogenic Molecule NSI-189. Diabetes 2019; 68:2143-2154. [PMID: 31492662 PMCID: PMC6804627 DOI: 10.2337/db19-0271] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 08/26/2019] [Indexed: 02/06/2023]
Abstract
While peripheral neuropathy is the most common complication of long-term diabetes, cognitive deficits associated with encephalopathy and myelopathy also occur. Diabetes is a risk factor for Alzheimer disease (AD) and increases the risk of progression from mild cognitive impairment to AD. The only current recommendation for preventing or slowing the progression of peripheral neuropathy is to maintain close glycemic control, while there is no recommendation for central nervous system disorders. NSI-189 is a new chemical entity that when orally administered promotes neurogenesis in the adult hippocampus, increases hippocampal volume, enhances synaptic plasticity, and reduces cognitive dysfunction. To establish the potential for impact on peripheral neuropathy, we first showed that NSI-189 enhances neurite outgrowth and mitochondrial functions in cultured adult rat primary sensory neurons. Oral delivery of NSI-189 to murine models of type 1 (female) and type 2 (male) diabetes prevented multiple functional and structural indices of small and large fiber peripheral neuropathy, increased hippocampal neurogenesis, synaptic markers and volume, and protected long-term memory. NSI-189 also halted progression of established peripheral and central neuropathy. NSI-189, which is currently in clinical trials for treatment of major depressive disorder, offers the opportunity for the development of a single therapeutic agent against multiple indices of central and peripheral neuropathy.
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Affiliation(s)
- Corinne G Jolivalt
- Department of Pathology, University of California, San Diego, La Jolla, CA
| | - Alexandra Marquez
- Department of Pathology, University of California, San Diego, La Jolla, CA
| | | | | | - Carlos Anaya
- Department of Pathology, University of California, San Diego, La Jolla, CA
| | - Betelhem Kifle
- Department of Pathology, University of California, San Diego, La Jolla, CA
| | - Nabeel Muttalib
- Department of Pathology, University of California, San Diego, La Jolla, CA
| | - Gabriela Sanchez
- Department of Pathology, University of California, San Diego, La Jolla, CA
| | - Lucy Guernsey
- Department of Pathology, University of California, San Diego, La Jolla, CA
| | | | - Darrel R Smith
- St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
| | - Paul Fernyhough
- St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
| | | | - Nigel A Calcutt
- Department of Pathology, University of California, San Diego, La Jolla, CA
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14
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Rolim LCSP, da Silva EMK, Flumignan RLG, Abreu MM, Dib SA. Acetyl-L-carnitine for the treatment of diabetic peripheral neuropathy. Cochrane Database Syst Rev 2019; 6:CD011265. [PMID: 31201734 PMCID: PMC6953387 DOI: 10.1002/14651858.cd011265.pub2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Diabetic peripheral neuropathy (DPN) is a common and severe complication that affects 50% of people with diabetes. Painful DPN is reported to occur in 16% to 24% of people with diabetes. A complete and comprehensive management strategy for the prevention and treatment of DPN, whether painful or not, has not yet been defined.Research into treatment for DPN has been characterised by a series of failed clinical trials, with few noteworthy advances. Strategies that support peripheral nerve regeneration and restore neurological function in people with painful or painless DPN are needed. The amino acid acetyl-L-carnitine (ALC) plays a role in the transfer of long-chain fatty acids into mitochondria for β-oxidation. ALC supplementation also induces neuroprotective and neurotrophic effects in the peripheral nervous system. Therefore, ALC supplementation targets several mechanisms relevant to potential nerve repair and regeneration, and could have clinical therapeutic potential. There is a need for a systematic review of the evidence from clinical trials. OBJECTIVES To assess the effects of ALC for the treatment of DPN. SEARCH METHODS On 2 July 2018, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform. We checked references, searched citations, and contacted study authors to identify additional studies. SELECTION CRITERIA We included randomised controlled trials (RCTs) and quasi-RCTs of ALC compared with placebo, other therapy, or no intervention in the treatment of DPN. Participants could be of any sex and age, and have type 1 or type 2 diabetes mellitus, of any severity, with painful or painless DPN. We accepted any definition of minimum criteria for DPN, in accordance with the Toronto Consensus. We imposed no language restriction.Pain was the primary outcome, measured as the proportion of participants with at least 30% (moderate) or 50% (substantial) decrease in pain over baseline, or as the score on a visual analogue scale (VAS) or Likert scale for pain. DATA COLLECTION AND ANALYSIS We followed standard Cochrane methods. MAIN RESULTS We included four studies with 907 participants, which were reported in three publications. Three trials studied ALC versus placebo (675 participants); in one trial the dose of ALC was 2000 mg/day, and in the other two trials, it was 1500 mg/day or 3000 mg/day. The fourth trial studied ALC 1500 mg/day versus methylcobalamin 1.5 mg/day (232 participants). The risk of bias was high in both trials of different ALC doses and low in the other two trials.No included trial measured the proportion of participants with at least moderate (30%) or substantial (50%) pain relief. ALC reduced pain more than placebo, measured on a 0- to 100-mm VAS (MD -9.16, 95% CI -16.76 to -1.57; three studies; 540 participants; P = 0.02; I² = 56%; random-effects; very low-certainty evidence; a higher score indicating more pain). At doses of 1500 mg/day or less, the VAS score after ALC treatment was little different from placebo (MD -0.05, 95% CI -10.00 to 9.89; two studies; 159 participants; P = 0.99; I² = 0%), but at doses greater than 1500 mg/day, ALC reduced pain more than placebo (MD -14.93, 95% CI -19.16 to -10.70; three studies; 381 participants; P < 0.00001; I² = 0%). This subgroup analysis should be viewed with caution as the evidence was even less certain than the overall analysis, which was already of very low certainty.Two placebo-controlled studies reported that vibration perception improved after 12 months. We graded this evidence as very low certainty, due to inconsistency and a high risk of bias, as the trial authors did not provide any numerical data. The placebo-controlled studies did not measure functional impairment and disability scores. No study used validated symptom scales. One study performed sensory testing, but the evidence was very uncertain.The fourth included study compared ALC with methylcobalamin, but did not report effects on pain. There was a reduction from baseline to 24 weeks in functional impairment and disability, based on the change in mean Neuropathy Disability Score (NDS; scale from zero to 10), but there was no important difference between the ALC group (mean score 1.66 ± 1.90) and the methylcobalamin group (mean score 1.35 ± 1.65) groups (P = 0.23; low-certainty evidence).One placebo-controlled study reported that six of 147 participants in the ALC > 1500 mg/day group (4.1%) and two of 147 participants in the placebo group (1.4%) discontinued treatment because of adverse events (headache, facial paraesthesia, and gastrointestinal disorders) (P = 0.17). The other two placebo-controlled studies reported no dropouts due to adverse events, and more pain, paraesthesia, and hyperaesthesias in the placebo group than the 3000 mg/day ALC group, but provided no numerical data. The overall certainty of adverse event evidence for the comparison of ALC versus placebo was low.The study comparing ALC with methylcobalamin reported that 34/117 participants (29.1%) experienced adverse events in the ALC group versus 33/115 (28.7%) in the methylcobalamin group (P = 0.95). Nine participants discontinued treatment due to adverse events (ALC: 4 participants, methylcobalamin: 5 participants), which were most commonly gastrointestinal symptoms. The certainty of the adverse event evidence for ALC versus methylcobalamin was low.Two studies were funded by the manufacturer of ALC and the other two studies had at least one co-author who was a consultant for an ALC manufacturer. AUTHORS' CONCLUSIONS We are very uncertain whether ALC causes a reduction in pain after 6 to 12 months' treatment in people with DPN, when compared with placebo, as the evidence is sparse and of low certainty. Data on functional and sensory impairment and symptoms are lacking, or of very low certainty. The evidence on adverse events is too uncertain to make any judgements on safety.
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Affiliation(s)
- Luiz CSP Rolim
- Universidade Federal de São PauloDepartment of Internal MedicineRua Borges Lagoa, 1065/110São PauloSão PauloBrazil04038‐032
| | - Edina MK da Silva
- Universidade Federal de São PauloEmergency Medicine and Evidence Based MedicineRua Borges Lagoa 564 cj 64Vl. ClementinoSão PauloSão PauloBrazil04038‐000
| | - Ronald LG Flumignan
- Universidade Federal de São PauloDepartment of Surgery, Division of Vascular and Endovascular SurgeryRua Borges Lagoa, 754São PauloSPBrazil04038‐001
| | - Marcio M Abreu
- Yale University School of MedicineAnaesthesiology and Critical Care Medicine333 Cedar Street, TMP 3P.O. Box 208051New HavenCTUSA06520‐8051
| | - Sérgio A Dib
- Universidade Federal de São PauloDepartment of Medicine / EndocrinologyRua Pedro de Toledo, 910São PauloSão PauloBrazil04038‐000
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Aghanoori MR, Smith DR, Shariati-Ievari S, Ajisebutu A, Nguyen A, Desmond F, Jesus CHA, Zhou X, Calcutt NA, Aliani M, Fernyhough P. Insulin-like growth factor-1 activates AMPK to augment mitochondrial function and correct neuronal metabolism in sensory neurons in type 1 diabetes. Mol Metab 2019; 20:149-165. [PMID: 30545741 PMCID: PMC6358538 DOI: 10.1016/j.molmet.2018.11.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/20/2018] [Accepted: 11/23/2018] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Diabetic sensorimotor polyneuropathy (DSPN) affects approximately half of diabetic patients leading to significant morbidity. There is impaired neurotrophic growth factor signaling, AMP-activated protein kinase (AMPK) activity and mitochondrial function in dorsal root ganglia (DRG) of animal models of type 1 and type 2 diabetes. We hypothesized that sub-optimal insulin-like growth factor 1 (IGF-1) signaling in diabetes drives loss of AMPK activity and mitochondrial function, both contributing to development of DSPN. METHODS Age-matched control Sprague-Dawley rats and streptozotocin (STZ)-induced type 1 diabetic rats with/without IGF-1 therapy were used for in vivo studies. For in vitro studies, DRG neurons from control and STZ-diabetic rats were cultured and treated with/without IGF-1 in the presence or absence of inhibitors or siRNAs. RESULTS Dysregulation of mRNAs for IGF-1, AMPKα2, ATP5a1 (subunit of ATPase), and PGC-1β occurred in DRG of diabetic vs. control rats. IGF-1 up-regulated mRNA levels of these genes in cultured DRGs from control or diabetic rats. IGF-1 treatment of DRG cultures significantly (P < 0.05) increased phosphorylation of Akt, P70S6K, AMPK and acetyl-CoA carboxylase (ACC). Mitochondrial gene expression and oxygen consumption rate (spare respiratory capacity), ATP production, mtDNA/nDNA ratio and neurite outgrowth were augmented (P < 0.05). AMPK inhibitor, Compound C, or AMPKα1-specific siRNA suppressed IGF-1 elevation of mitochondrial function, mtDNA and neurite outgrowth. Diabetic rats treated with IGF-1 exhibited reversal of thermal hypoalgesia and, in a separate study, reversed the deficit in corneal nerve profiles. In diabetic rats, IGF-1 elevated the levels of AMPK and P70S6K phosphorylation, raised Complex IV-MTCO1 and Complex V-ATP5a protein expression, and restored the enzyme activities of Complex IV and I in the DRG. IGF-1 prevented TCA metabolite build-up in nerve. CONCLUSIONS In DRG neuron cultures IGF-1 signals via AMPK to elevate mitochondrial function and drive axonal outgrowth. We propose that this signaling axis mediates IGF-1-dependent protection from distal dying-back of fibers in diabetic neuropathy.
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Affiliation(s)
- Mohamad-Reza Aghanoori
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada; Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB, Canada
| | - Darrell R Smith
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | - Shiva Shariati-Ievari
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada
| | - Andrew Ajisebutu
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | - Annee Nguyen
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Fiona Desmond
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Carlos H A Jesus
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Xiajun Zhou
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Nigel A Calcutt
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Michel Aliani
- Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, Canada; Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada; Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Canada
| | - Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada; Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB, Canada.
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16
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Kobayashi M, Zochodne DW. Diabetic neuropathy and the sensory neuron: New aspects of pathogenesis and their treatment implications. J Diabetes Investig 2018; 9:1239-1254. [PMID: 29533535 PMCID: PMC6215951 DOI: 10.1111/jdi.12833] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/20/2018] [Accepted: 03/03/2018] [Indexed: 12/17/2022] Open
Abstract
Diabetic polyneuropathy (DPN) continues to be generally considered as a "microvascular" complication of diabetes mellitus alongside nephropathy and retinopathy. The microvascular hypothesis, however, might be tempered by the concept that diabetes directly targets dorsal root ganglion sensory neurons. This neuron-specific concept, supported by accumulating evidence, might account for important features of DPN, such as its early sensory neuron degeneration. Diabetic sensory neurons develop neuronal atrophy alongside a series of messenger ribonucleic acid (RNA) changes related to declines in structural proteins, increases in heat shock protein, increases in the receptor for advanced glycation end-products, declines in growth factor signaling and other changes. Insulin is recognized as a potent neurotrophic factor, and insulin ligation enhances neurite outgrowth through activation of the phosphoinositide 3-kinase-protein kinase B pathway within sensory neurons and attenuates phenotypic features of experimental DPN. Several interventions, including glucagon-like peptide-1 agonism, and phosphatase and tensin homolog inhibition to activate growth signals in sensory neurons, or heat shock protein overexpression, prevent or reverse neuropathic abnormalities in experimental DPN. Diabetic sensory neurons show a unique pattern of microRNA alterations, a key element of messenger RNA silencing. For example, let-7i is widely expressed in sensory neurons, supports their growth and is depleted in experimental DPN; its replenishment improves features of DPN models. Finally, impairment of pre-messenger RNA splicing in diabetic sensory neurons including abnormal nuclear RNA metabolism and structure with loss of survival motor neuron protein, a neuron survival molecule, and overexpression of CWC22, a splicing factor, offer further novel insights. The present review addresses these new aspects of DPN sensory neurodegeneration.
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Affiliation(s)
- Masaki Kobayashi
- Department of Neurology and Neurological ScienceGraduate School of MedicineTokyo Medical and Dental UniversityTokyoJapan
- Department of NeurologyYokufukai Geriatric HospitalTokyoJapan
| | - Douglas W Zochodne
- Division of Neurology and Department of MedicineNeuroscience and Mental Health InstituteFaculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
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17
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Marunaka Y. The Proposal of Molecular Mechanisms of Weak Organic Acids Intake-Induced Improvement of Insulin Resistance in Diabetes Mellitus via Elevation of Interstitial Fluid pH. Int J Mol Sci 2018; 19:ijms19103244. [PMID: 30347717 PMCID: PMC6214001 DOI: 10.3390/ijms19103244] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 09/30/2018] [Accepted: 10/17/2018] [Indexed: 02/07/2023] Open
Abstract
Blood contains powerful pH-buffering molecules such as hemoglobin (Hb) and albumin, while interstitial fluids have little pH-buffering molecules. Thus, even under metabolic disorder conditions except severe cases, arterial blood pH is kept constant within the normal range (7.35~7.45), but the interstitial fluid pH under metabolic disorder conditions becomes lower than the normal level. Insulin resistance is one of the most important key factors in pathogenesis of diabetes mellitus, nevertheless the molecular mechanism of insulin resistance occurrence is still unclear. Our studies indicate that lowered interstitial fluid pH occurs in diabetes mellitus, causing insulin resistance via reduction of the binding affinity of insulin to its receptor. Therefore, the key point for improvement of insulin resistance occurring in diabetes mellitus is development of methods or techniques elevating the lowered interstitial fluid pH. Intake of weak organic acids is found to improve the insulin resistance by elevating the lowered interstitial fluid pH in diabetes mellitus. One of the molecular mechanisms of the pH elevation is that: (1) the carboxyl group (R-COO−) but not H+ composing weak organic acids in foods is absorbed into the body, and (2) the absorbed the carboxyl group (R-COO−) behaves as a pH buffer material, elevating the interstitial fluid pH. On the other hand, high salt intake has been suggested to cause diabetes mellitus; however, the molecular mechanism is unclear. A possible mechanism of high salt intake-caused diabetes mellitus is proposed from a viewpoint of regulation of the interstitial fluid pH: high salt intake lowers the interstitial fluid pH via high production of H+ associated with ATP synthesis required for the Na+,K+-ATPase to extrude the high leveled intracellular Na+ caused by high salt intake. This review article introduces the molecular mechanism causing the lowered interstitial fluid pH and insulin resistance in diabetes mellitus, the improvement of insulin resistance via intake of weak organic acid-containing foods, and a proposal mechanism of high salt intake-caused diabetes mellitus.
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Affiliation(s)
- Yoshinori Marunaka
- Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto 604-8472, Japan.
- Research Center for Drug Discovery and Pharmaceutical Development Science, Research Organization of Science and Technology, Ritsumeikan University, Kusatsu 525-8577, Japan.
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
- Japan Institute for Food Education and Health, St. Agnes' University, Kyoto 602-8013, Japan.
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18
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Schartner E, Sabbir MG, Saleh A, Silva RV, Roy Chowdhury S, Smith DR, Fernyhough P. High glucose concentration suppresses a SIRT2 regulated pathway that enhances neurite outgrowth in cultured adult sensory neurons. Exp Neurol 2018; 309:134-147. [PMID: 30102915 DOI: 10.1016/j.expneurol.2018.08.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 08/05/2018] [Accepted: 08/09/2018] [Indexed: 12/21/2022]
Abstract
In peripheral nerve under hyperglycemic conditions high flux of d-glucose through the polyol pathway drives an aberrant redox state contributing to neurodegeneration in diabetic sensorimotor polyneuropathy (DSPN). Sirtuins, including SIRT2, detect the redox state via the NAD+/NADH ratio to regulate mitochondrial function via, in part, AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α). In adult dorsal root ganglia (DRG) sensory neurons mitochondrial dysfunction has been proposed as an etiological factor in dying-back neuropathy in diabetes. We tested the hypothesis that a high concentration of d-glucose depleted SIRT2 expression via enhancement of polyol pathway activity. We posited that this would lead to impaired mitochondrial function and suppression of neurite outgrowth in cultured sensory neurons. The use of dominant negative mutants or neurons from SIRT2 knockout (KO) mice to block SIRT2 signaling revealed that neurons derived from control or type 1 diabetic rodents required SIRT2 for optimal neurite outgrowth. Over-expression of WT-SIRT2 elevated neurite outgrowth in normal and diabetic cultures. SIRT2 protein isoforms 2.1 and 2.2 were reduced by 20-30% in DRG of type 1 diabetic mice (p < .05). After 72 h exposure to high d-glucose (25 mM vs 5 mM) cultured sensory neurons showed a significant 2-fold (p < .05) decrease in SIRT2 expression, P-AMPK, levels of respiratory Complexes II/III and respiratory capacity. DRG neurons expressed aldose reductase and the aforementioned deficits were prevented by treatment with aldose reductase inhibitors (lidorestat or sorbinil) or sorbitol dehydrogenase inhibitor (SDI-158). In cultures derived from type 1 diabetic rats treatment with SDI-158 elevated expression of SIRT2, P-AMPK/PGC-1α and neurite outgrowth (p < .05). SIRT2 KO neurons exhibited deficits in the LKB-1/AMPK/PGC-1α pathway and mitochondrial function. In cultured neurons the SIRT2 pathway enhances axonal outgrowth and this signaling axis encompassing activation of AMPK/PGC-1α is impaired in DSPN, in part, due to enhanced polyol pathway activity caused by hyperglycemia.
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Affiliation(s)
- Emily Schartner
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada; Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Canada
| | - Mohammad Golam Sabbir
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada
| | - Ali Saleh
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada
| | - Rafaela Vieira Silva
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Canada; Faculty of Pharmacy, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, Brazil
| | - Subir Roy Chowdhury
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada
| | - Darrell R Smith
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada
| | - Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, Canada; Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, Canada.
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19
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Im SH, Patel AA, Cox DN, Galko MJ. Drosophila Insulin receptor regulates the persistence of injury-induced nociceptive sensitization. Dis Model Mech 2018; 11:dmm034231. [PMID: 29752280 PMCID: PMC5992604 DOI: 10.1242/dmm.034231] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 03/25/2018] [Indexed: 12/12/2022] Open
Abstract
Diabetes-associated nociceptive hypersensitivity affects diabetic patients with hard-to-treat chronic pain. Because multiple tissues are affected by systemic alterations in insulin signaling, the functional locus of insulin signaling in diabetes-associated hypersensitivity remains obscure. Here, we used Drosophila nociception/nociceptive sensitization assays to investigate the role of Insulin receptor (Insulin-like receptor, InR) in nociceptive hypersensitivity. InR mutant larvae exhibited mostly normal baseline thermal nociception (absence of injury) and normal acute thermal hypersensitivity following UV-induced injury. However, their acute thermal hypersensitivity persists and fails to return to baseline, unlike in controls. Remarkably, injury-induced persistent hypersensitivity is also observed in larvae that exhibit either type 1 or type 2 diabetes. Cell type-specific genetic analysis indicates that InR function is required in multidendritic sensory neurons including nociceptive class IV neurons. In these same nociceptive sensory neurons, only modest changes in dendritic morphology were observed in the InRRNAi -expressing and diabetic larvae. At the cellular level, InR-deficient nociceptive sensory neurons show elevated calcium responses after injury. Sensory neuron-specific expression of InR rescues the persistent thermal hypersensitivity of InR mutants and constitutive activation of InR in sensory neurons ameliorates the hypersensitivity observed with a type 2-like diabetic state. Our results suggest that a sensory neuron-specific function of InR regulates the persistence of injury-associated hypersensitivity. It is likely that this new system will be an informative genetically tractable model of diabetes-associated hypersensitivity.
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Affiliation(s)
- Seol Hee Im
- Department of Genetics, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Atit A Patel
- Neuroscience Institute, Georgia State University, P.O. Box 5030, Atlanta, GA 30303, USA
| | - Daniel N Cox
- Neuroscience Institute, Georgia State University, P.O. Box 5030, Atlanta, GA 30303, USA
| | - Michael J Galko
- Department of Genetics, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
- Genetics and Epigenetics Graduate Program, University of Texas Graduate School of Biomedical Sciences, 6767 Bertner Avenue, Houston, TX 77030, USA
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20
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Daugherty DJ, Marquez A, Calcutt NA, Schubert D. A novel curcumin derivative for the treatment of diabetic neuropathy. Neuropharmacology 2018; 129:26-35. [PMID: 29122628 PMCID: PMC5841546 DOI: 10.1016/j.neuropharm.2017.11.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 11/03/2017] [Accepted: 11/04/2017] [Indexed: 12/16/2022]
Abstract
Neuropathy is a common complication of long-term diabetes. Proposed mechanisms of neuronal damage caused by diabetes that are downstream of hyperglycemia and/or loss of insulin signaling include ischemic hypoxia, inflammation and loss of neurotrophic support. The curcumin derivative J147 is a potent neurogenic and neuroprotective drug candidate initially developed for the treatment of neurodegenerative conditions associated with aging that impacts many pathways implicated in the pathogenesis of diabetic neuropathy. Here, we demonstrate efficacy of J147 in ameliorating multiple indices of neuropathy in the streptozotocin-induced mouse model of type 1 diabetes. Diabetes was determined by blood glucose, HbA1c, and insulin levels and efficacy of J147 by behavioral, physiologic, biochemical, proteomic, and transcriptomic assays. Biological efficacy of systemic J147 treatment was confirmed by its capacity to decrease TNFα pathway activation and several other markers of neuroinflammation in the CNS. Chronic oral treatment with J147 protected the sciatic nerve from progressive diabetes-induced slowing of large myelinated fiber conduction velocity while single doses of J147 rapidly and transiently reversed established touch-evoked allodynia. Conduction slowing and allodynia are clinically relevant markers of early diabetic neuropathy and neuropathic pain, respectively. RNA expression profiling suggests that one of the pathways by which J147 imparts its protection against diabetic induced neuropathy may be through activation of the AMP kinase pathway. The diverse biological and therapeutic effects of J147 suggest it as an alternative to the polypharmaceutical approaches required to treat the multiple pathogenic mechanisms that contribute to diabetic neuropathy.
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Affiliation(s)
| | | | | | - David Schubert
- The Salk Institute for Biological Studies, La Jolla, CA, USA
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21
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Aghanoori MR, Smith DR, Roy Chowdhury S, Sabbir MG, Calcutt NA, Fernyhough P. Insulin prevents aberrant mitochondrial phenotype in sensory neurons of type 1 diabetic rats. Exp Neurol 2017; 297:148-157. [PMID: 28803751 DOI: 10.1016/j.expneurol.2017.08.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 08/02/2017] [Accepted: 08/10/2017] [Indexed: 01/08/2023]
Abstract
Diabetic neuropathy affects approximately 50% of diabetic patients. Down-regulation of mitochondrial gene expression and function has been reported in both human tissues and in dorsal root ganglia (DRG) from animal models of type 1 and type 2 diabetes. We hypothesized that loss of direct insulin signaling in diabetes contributes to loss of mitochondrial function in DRG neurons and to development of neuropathy. Sensory neurons obtained from age-matched adult control or streptozotocin (STZ)-induced type 1 diabetic rats were cultured with or without insulin before determining mitochondrial respiration and expression of mitochondrial respiratory chain and insulin signaling-linked proteins. For in vivo studies age-matched control rats and diabetic rats with or without trace insulin supplementation were maintained for 5months before DRG were analyzed for respiratory chain gene expression and cytochrome c oxidase activity. Insulin (10nM) significantly (P<0.05) increased phosphorylation of Akt and P70S6K by 4-fold and neurite outgrowth by 2-fold in DRG cultures derived from adult control rats. Insulin also augmented the levels of selective mitochondrial respiratory chain proteins and mitochondrial bioenergetics parameters in DRG cultures from control and diabetic rats, with spare respiratory capacity increased by up to 3-fold (P<0.05). Insulin-treated diabetic animals exhibited improved thermal sensitivity in the hind paw and had increased dermal nerve density compared to untreated diabetic rats, despite no effect on blood glucose levels. In DRG of diabetic rats there was suppressed expression of mitochondrial respiratory chain proteins and cytochrome c oxidase activity that was corrected by insulin therapy. Insulin elevates mitochondrial respiratory chain protein expression and function in sensory neurons and this is associated with enhanced neurite outgrowth and protection against indices of neuropathy.
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Affiliation(s)
- Mohamad-Reza Aghanoori
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB, Canada; Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB, Canada
| | - Darrell R Smith
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB, Canada
| | - Subir Roy Chowdhury
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB, Canada
| | - Mohammad Golam Sabbir
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB, Canada
| | - Nigel A Calcutt
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB, Canada; Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB, Canada.
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22
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de la Hoz CL, Cheng C, Fernyhough P, Zochodne DW. A model of chronic diabetic polyneuropathy: benefits from intranasal insulin are modified by sex and RAGE deletion. Am J Physiol Endocrinol Metab 2017; 312:E407-E419. [PMID: 28223295 PMCID: PMC5451527 DOI: 10.1152/ajpendo.00444.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/06/2017] [Accepted: 02/18/2017] [Indexed: 01/11/2023]
Abstract
Human diabetic polyneuropathy (DPN) is a progressive complication of chronic diabetes mellitus. Preliminary evidence has suggested that intranasal insulin, in doses insufficient to alter hyperglycemia, suppresses the development of DPN. In this work we confirm this finding, but demonstrate that its impact is modified by sex and deletion of RAGE, the receptor for advanced glycosylation end products. We serially evaluated experimental DPN in male and female wild-type mice and male RAGE null (RN) mice, each with nondiabetic controls, during 16 wk of diabetes, the final 8 wk including groups given intranasal insulin. Age-matched nondiabetic female mice had higher motor and sensory conduction velocities than their male counterparts and had lesser conduction slowing from chronic diabetes. Intranasal insulin improved slowing in both sexes. In male RN mice, there was less conduction slowing with chronic diabetes, and intranasal insulin provided limited benefits. Rotarod testing and hindpaw grip power offered less consistent impacts. Mechanical sensitivity and thermal sensitivity were respectively but disparately changed and improved with insulin in wild-type female and male mice but not RN male mice. These studies confirm that intranasal insulin improves indexes of experimental DPN but indicates that females with DPN may differ in their underlying phenotype. RN mice had partial but incomplete protection from underlying DPN and lesser impacts from insulin. We also identify an important role for sex in the development of DPN and report evidence that insulin and AGE-RAGE pathways in its pathogenesis may overlap.
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Affiliation(s)
- Cristiane L de la Hoz
- Department of Clinical Neurosciences, the Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; and
| | - Chu Cheng
- Department of Clinical Neurosciences, the Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; and
| | - Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre and Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Douglas W Zochodne
- Division of Neurology, Department of Medicine, Neuroscience and Mental Health Institute, Alberta Diabetes Institute, University of Alberta, Alberta, Canada;
- Department of Clinical Neurosciences, the Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; and
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23
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Gonçalves NP, Vægter CB, Andersen H, Østergaard L, Calcutt NA, Jensen TS. Schwann cell interactions with axons and microvessels in diabetic neuropathy. Nat Rev Neurol 2017; 13:135-147. [PMID: 28134254 DOI: 10.1038/nrneurol.2016.201] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The prevalence of diabetes worldwide is at pandemic levels, with the number of patients increasing by 5% annually. The most common complication of diabetes is peripheral neuropathy, which has a prevalence as high as 50% and is characterized by damage to neurons, Schwann cells and blood vessels within the nerve. The pathogenic mechanisms of diabetic neuropathy remain poorly understood, impeding the development of targeted therapies to treat nerve degeneration and its most disruptive consequences of sensory loss and neuropathic pain. Involvement of Schwann cells has long been proposed, and new research techniques are beginning to unravel a complex interplay between these cells, axons and microvessels that is compromised during the development of diabetic neuropathy. In this Review, we discuss the evolving concept of Schwannopathy as an integral factor in the pathogenesis of diabetic neuropathy, and how disruption of the interactions between Schwann cells, axons and microvessels contribute to the disease.
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Affiliation(s)
- Nádia P Gonçalves
- The International Diabetic Neuropathy Consortium (IDNC), Aarhus University, Nørrebrogade, 8000 Aarhus C, Denmark
| | - Christian B Vægter
- Danish Research Institute of Translational Neuroscience DANDRITE, Nordic-EMBL Partnership, Department of Biomedicine, Aarhus University, Ole Worms Alle 3, 8000 Aarhus C, Denmark
| | - Henning Andersen
- Department of Neurology, Danish Pain Research Center and IDNC, Aarhus University Hospital, Nørrebrogade, 8000 Aarhus C, Denmark
| | - Leif Østergaard
- Department of Neuroradiology and Center for Functionally Integrative Neuroscience, Aarhus University Hospital, Nørrebrogade, 8000 Aarhus C, Denmark
| | - Nigel A Calcutt
- Department of Pathology, University of California San Diego, Gilman Drive, La Jolla, California 92093, USA
| | - Troels S Jensen
- Department of Neurology, Danish Pain Research Center and IDNC, Aarhus University Hospital, Nørrebrogade, 8000 Aarhus C, Denmark
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