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van Gool R, Far A, Drenthen GS, Jansen JFA, Goijen CP, Backes WH, Linden DEJ, Merkies ISJ, Faber CG, Upadhyay J, Hoeijmakers JGJ. Peripheral Pain Captured Centrally: Altered Brain Morphology on MRI in Small Fiber Neuropathy Patients With and Without an SCN9A Gene Variant. THE JOURNAL OF PAIN 2024; 25:730-741. [PMID: 37921732 DOI: 10.1016/j.jpain.2023.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 09/05/2023] [Accepted: 10/03/2023] [Indexed: 11/04/2023]
Abstract
The current study aims to characterize brain morphology of pain as reported by small fiber neuropathy (SFN) patients with or without a gain-of-function variant involving the SCN9A gene and compare these with findings in healthy controls without pain. The Neuropathic Pain Scale was used in patients with idiopathic SFN (N = 20) and SCN9A-associated SFN (N = 12) to capture pain phenotype. T1-weighted, structural magnetic resonance imaging (MRI) data were collected in patients and healthy controls (N = 21) to 1) compare cortical thickness and subcortical volumes and 2) quantify the association between severity, quality, and duration of pain with morphological properties. SCN9A-associated SFN patients showed significant (P < .017, Bonferroni corrected) higher cortical thickness in sensorimotor regions, compared to idiopathic SFN patients, while lower cortical thickness was found in more functionally diverse regions (eg, posterior cingulate cortex). SFN patient groups combined demonstrated a significant (Spearman's ρ = .44-.55, P = .005-.049) correlation among itch sensations (Neuropathic Pain Scale-7) and thickness of the left precentral gyrus, and midcingulate cortices. Significant associations were found between thalamic volumes and duration of pain (left: ρ = -.37, P = .043; right: ρ = -.40, P = .025). No associations were found between morphological properties and other pain qualities. In conclusion, in SCN9A-associated SFN, profound morphological alterations anchored within the pain matrix are present. The association between itch sensations of pain and sensorimotor and midcingulate structures provides a novel basis for further examining neurobiological underpinnings of itch in SFN. PERSPECTIVE: Cortical thickness and subcortical volume alterations in SFN patients were found in pain hubs, more profound in SCN9A-associated neuropathy, and correlated with itch and durations of pain. These findings contribute to our understanding of the pathophysiological pathways underlying chronic neuropathic pain and symptoms of itch in SFN.
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Affiliation(s)
- Raquel van Gool
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Limburg, The Netherlands
| | - Amir Far
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Limburg, The Netherlands; Department of Neurology, Maastricht University Medical Center+, Maastricht, Limburg, The Netherlands
| | - Gerhard S Drenthen
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Limburg, The Netherlands; Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, Limburg, The Netherlands
| | - Jacobus F A Jansen
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Limburg, The Netherlands; Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, Limburg, The Netherlands; Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, North Brabant, The Netherlands
| | - Celine P Goijen
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Limburg, The Netherlands; Department of Neurology, Maastricht University Medical Center+, Maastricht, Limburg, The Netherlands
| | - Walter H Backes
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Limburg, The Netherlands; Department of Radiology and Nuclear Medicine, Maastricht University Medical Center+, Maastricht, Limburg, The Netherlands
| | - David E J Linden
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Limburg, The Netherlands; Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Limburg, The Netherlands
| | - Ingemar S J Merkies
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Limburg, The Netherlands; Department of Neurology, Maastricht University Medical Center+, Maastricht, Limburg, The Netherlands; Department of Neurology, Curaçao Medical Center, Willemstad, Kingdom of the Netherlands, Curaçao
| | - Catharina G Faber
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Limburg, The Netherlands; Department of Neurology, Maastricht University Medical Center+, Maastricht, Limburg, The Netherlands
| | - Jaymin Upadhyay
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, Massachusetts
| | - Janneke G J Hoeijmakers
- School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Limburg, The Netherlands; Department of Neurology, Maastricht University Medical Center+, Maastricht, Limburg, The Netherlands
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Function of the GABAergic System in Diabetic Encephalopathy. Cell Mol Neurobiol 2023; 43:605-619. [PMID: 35460435 DOI: 10.1007/s10571-022-01214-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 03/17/2022] [Indexed: 11/03/2022]
Abstract
Diabetes is a common metabolic disease characterized by loss of blood sugar control and a high rate of complications. γ-Aminobutyric acid (GABA) functions as the primary inhibitory neurotransmitter in the adult mammalian brain. The normal function of the GABAergic system is affected in diabetes. Herein, we summarize the role of the GABAergic system in diabetic cognitive dysfunction, diabetic blood sugar control disorders, diabetes-induced peripheral neuropathy, diabetic central nervous system damage, maintaining diabetic brain energy homeostasis, helping central control of blood sugar and attenuating neuronal oxidative stress damage. We show the key regulatory role of the GABAergic system in multiple comorbidities in patients with diabetes and hope that further studies elucidating the role of the GABAergic system will yield benefits for the treatment and prevention of comorbidities in patients with diabetes.
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Gandhi R, Selvarajah D, Sloan G, Greig M, Wilkinson ID, Shaw PJ, Griffiths P, Tesfaye S. Preservation of thalamic neuronal function may be a prerequisite for pain perception in diabetic neuropathy: A magnetic resonance spectroscopy study. FRONTIERS IN PAIN RESEARCH (LAUSANNE, SWITZERLAND) 2023; 3:1086887. [PMID: 36688084 PMCID: PMC9852821 DOI: 10.3389/fpain.2022.1086887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 11/24/2022] [Indexed: 01/09/2023]
Abstract
Introduction In this study, we used proton Magnetic Resonance Spectroscopy (1H-MRS) to determine the neuronal function in the thalamus and primary somatosensory (S1) cortex in different subgroups of DPN, including subclinical- and painful-DPN. Method One-hundred and ten people with type 1 diabetes [20 without DPN (no-DPN); 30 with subclinical-DPN; 30 with painful-DPN; and 30 with painless-DPN] and 20 healthy volunteers, all of whom were right-handed men, were recruited and underwent detailed clinical and neurophysiological assessments. Participants underwent Magnetic Resonance Imaging at 1.5 Tesla with two 1H-MRS spectra obtained from 8 ml cubic volume voxels: one placed within left thalamus to encompass the ventro-posterior lateral sub-nucleus and another within the S1 cortex. Results In the thalamus, participants with painless-DPN had a significantly lower NAA:Cr ratio [1.55 + 0.22 (mean ± SD)] compared to all other groups [HV (1.80 ± 0.23), no-DPN (1.85 ± 0.20), sub-clinical DPN (1.79 ± 0.23), painful-DPN (1.75 ± 0.19), ANOVA p < 0.001]. There were no significant group differences in S1 cortical neurometabolites. Conclusion In this largest cerebral MRS study in DPN, thalamic neuronal dysfunction was found in advanced painless-DPN with preservation of function in subclinical- and painful-DPN. Furthermore, there was a preservation of neuronal function within the S1 cortex in all subgroups of DPN. Therefore, there may be a proximo-distal gradient to central nervous system alterations in painless-DPN, with thalamic neuronal dysfunction occurring only in established DPN. Moreover, these results further highlight the manifestation of cerebral alterations between painful- and painless-DPN whereby preservation of thalamic function may be a prerequisite for neuropathic pain in DPN.
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Affiliation(s)
- Rajiv Gandhi
- Diabetes Research Unit, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom
| | - Dinesh Selvarajah
- Department of Oncology and Human Metabolism, University of Sheffield, Sheffield, United Kingdom
| | - Gordon Sloan
- Diabetes Research Unit, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom,Department of Oncology and Human Metabolism, University of Sheffield, Sheffield, United Kingdom
| | - Marni Greig
- Diabetes Research Unit, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom
| | - Iain D. Wilkinson
- Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom
| | - Pamela J. Shaw
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Paul Griffiths
- Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom
| | - Solomon Tesfaye
- Diabetes Research Unit, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom,Correspondence: Solomon Tesfaye
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Wang D, Lee KY, Lee D, Kagan ZB, Bradley K. Low-Intensity 10 kHz Spinal Cord Stimulation Reduces Behavioral and Neural Hypersensitivity in a Rat Model of Painful Diabetic Neuropathy. J Pain Res 2022; 15:1503-1513. [PMID: 35637766 PMCID: PMC9148201 DOI: 10.2147/jpr.s358427] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 03/25/2022] [Indexed: 12/25/2022] Open
Abstract
Background Methods Results Conclusion
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Affiliation(s)
- Dong Wang
- Nevro Corp, Redwood City, CA, 94065, USA
| | | | | | | | - Kerry Bradley
- Nevro Corp, Redwood City, CA, 94065, USA
- Correspondence: Kerry Bradley, Nevro Corp, 1800 Bridge Pkwy, Redwood City, CA, 94065, USA, Email
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Busa P, Kuthati Y, Huang N, Wong CS. New Advances on Pathophysiology of Diabetes Neuropathy and Pain Management: Potential Role of Melatonin and DPP-4 Inhibitors. Front Pharmacol 2022; 13:864088. [PMID: 35496279 PMCID: PMC9039240 DOI: 10.3389/fphar.2022.864088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/14/2022] [Indexed: 12/14/2022] Open
Abstract
Pre-diabetes and diabetes are growing threats to the modern world. Diabetes mellitus (DM) is associated with comorbidities such as hypertension (83.40%), obesity (90.49%), and dyslipidemia (93.43%), creating a substantial burden on patients and society. Reductive and oxidative (Redox) stress level imbalance and inflammation play an important role in DM progression. Various therapeutics have been investigated to treat these neuronal complications. Melatonin and dipeptidyl peptidase IV inhibitors (DPP-4i) are known to possess powerful antioxidant and anti-inflammatory properties and have garnered significant attention in the recent years. In this present review article, we have reviewed the recently published reports on the therapeutic efficiency of melatonin and DPP-4i in the treatment of DM. We summarized the efficacy of melatonin and DPP-4i in DM and associated complications of diabetic neuropathy (DNP) and neuropathic pain. Furthermore, we discussed the mechanisms of action and their efficacy in the alleviation of oxidative stress in DM.
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Affiliation(s)
- Prabhakar Busa
- Department of Anesthesiology, Cathay General Hospital, Taipei, Taiwan
| | - Yaswanth Kuthati
- Department of Anesthesiology, Cathay General Hospital, Taipei, Taiwan
| | - Niancih Huang
- Department of Anesthesiology, Tri-Service General Hospital, Taipei, Taiwan
- Grauate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Chih-Shung Wong
- Department of Anesthesiology, Cathay General Hospital, Taipei, Taiwan
- Department of Anesthesiology, Tri-Service General Hospital, Taipei, Taiwan
- Grauate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
- *Correspondence: Chih-Shung Wong,
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6
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Sloan G, Selvarajah D, Tesfaye S. Pathogenesis, diagnosis and clinical management of diabetic sensorimotor peripheral neuropathy. Nat Rev Endocrinol 2021; 17:400-420. [PMID: 34050323 DOI: 10.1038/s41574-021-00496-z] [Citation(s) in RCA: 158] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/15/2021] [Indexed: 02/08/2023]
Abstract
Diabetic sensorimotor peripheral neuropathy (DSPN) is a serious complication of diabetes mellitus and is associated with increased mortality, lower-limb amputations and distressing painful neuropathic symptoms (painful DSPN). Our understanding of the pathophysiology of the disease has largely been derived from animal models, which have identified key potential mechanisms. However, effective therapies in preclinical models have not translated into clinical trials and we have no universally accepted disease-modifying treatments. Moreover, the condition is generally diagnosed late when irreversible nerve damage has already taken place. Innovative point-of-care devices have great potential to enable the early diagnosis of DSPN when the condition might be more amenable to treatment. The management of painful DSPN remains less than optimal; however, studies suggest that a mechanism-based approach might offer an enhanced benefit in certain pain phenotypes. The management of patients with DSPN involves the control of individualized cardiometabolic targets, a multidisciplinary approach aimed at the prevention and management of foot complications, and the timely diagnosis and management of neuropathic pain. Here, we discuss the latest advances in the mechanisms of DSPN and painful DSPN, originating both from the periphery and the central nervous system, as well as the emerging diagnostics and treatments.
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Affiliation(s)
- Gordon Sloan
- Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
| | - Dinesh Selvarajah
- Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK
- Department of Oncology and Human Metabolism, University of Sheffield, Sheffield, UK
| | - Solomon Tesfaye
- Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK.
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Elina KC, Oh BH, Islam J, Kim S, Park YS. Activation of CamKIIα expressing neurons on ventrolateral periaqueductal gray improves behavioral hypersensitivity and thalamic discharge in a trigeminal neuralgia rat model. J Headache Pain 2021; 22:47. [PMID: 34044756 PMCID: PMC8161973 DOI: 10.1186/s10194-021-01257-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 05/11/2021] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Preceding studies have reported the association of chronic neuropathic orofacial pain with altered ongoing function in the ventrolateral periaqueductal gray (vlPAG). However, its role in trigeminal neuralgia (TN) lacks attention. We here reported the aspect that vlPAG neurons play in TN nociceptive processing by employing excitatory neuron-specific optogenetic approaches. METHODS TN was generated via unilateral infraorbital nerve chronic constriction in Sprague Dawley rats which induced mechanical and thermal pain sensitivity in air puff and acetone test, respectively. Channelrhodopsin conjugated virus with CamKIIα promoter was used to specifically activate the excitatory vlPAG neuronal population by optogenetic stimulation and in vivo microdialysis was done to determine its effect on the excitatory-inhibitory balance. In vivo extracellular recordings from ventral posteromedial (VPM) thalamus were assessed in response to vlPAG optogenetic stimulation. Depending on the experimental terms, unpaired student's t test and two-way analysis of variance (ANOVA) were used for statistical analysis. RESULTS We observed that optogenetic activation of vlPAG subgroup neurons markedly improved pain hypersensitivity in reflexive behavior tests which was also evident on microdialysis analysis with increase glutamate concentration during stimulation period. Decreased mean firing and burst rates were evident in VPM thalamic electrophysiological recordings during the stimulation period. Overall, our results suggest the optogenetic activation of vlPAG excitatory neurons in a TN rat model has pain ameliorating effect. CONCLUSIONS This article presents the prospect of pain modulation in trigeminal pain pathway via optogenetic activation of vlPAG excitatory neurons in rat model. This outlook could potentially assist vlPAG insight and its optogenetic approach in trigeminal neuropathic pain which aid clinicians endeavoring towards enhanced pain relief therapy in trigeminal neuralgia patients.
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Affiliation(s)
- K C Elina
- Department of Neuroscience, College of Medicine, Chungbuk National University, Cheongju, South Korea
| | - Byeong Ho Oh
- Department of Neuroscience, College of Medicine, Chungbuk National University, Cheongju, South Korea
- Department of Neurosurgery, Chungbuk National University Hospital, Cheongju, South Korea
| | - Jaisan Islam
- Department of Neuroscience, College of Medicine, Chungbuk National University, Cheongju, South Korea
| | - Soochong Kim
- Department of Veterinary Medicine, Chungbuk National University, Cheongju, South Korea
| | - Young Seok Park
- Department of Neuroscience, College of Medicine, Chungbuk National University, Cheongju, South Korea.
- Department of Neurosurgery, Chungbuk National University Hospital, Cheongju, South Korea.
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Groener JB, Jende JME, Kurz FT, Kender Z, Treede RD, Schuh-Hofer S, Nawroth PP, Bendszus M, Kopf S. Understanding Diabetic Neuropathy-From Subclinical Nerve Lesions to Severe Nerve Fiber Deficits: A Cross-Sectional Study in Patients With Type 2 Diabetes and Healthy Control Subjects. Diabetes 2020; 69:436-447. [PMID: 31826867 DOI: 10.2337/db19-0197] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 12/05/2019] [Indexed: 11/13/2022]
Abstract
Studies on magnetic resonance neurography (MRN) in diabetic polyneuropathy (DPN) have found proximal sciatic nerve lesions. The aim of this study was to evaluate the functional relevance of sciatic nerve lesions in DPN, with the expectation of correlations with the impairment of large-fiber function. Sixty-one patients with type 2 diabetes (48 with and 13 without DPN) and 12 control subjects were enrolled and underwent MRN, quantitative sensory testing, and electrophysiological examinations. There were differences in mechanical detection (Aβ fibers) and mechanical pain (Aδ fibers) but not in thermal pain and thermal detection clusters (C fibers) among the groups. Lesion load correlated with lower Aα-, Aβ-, and Aδ-fiber but not with C-fiber function in all participants. Patients with lower function showed a higher load of nerve lesions than patients with elevated function or no measurable deficit despite apparent DPN. Longer diabetes duration was associated with higher lesion load in patients with DPN, suggesting that nerve lesions in DPN may accumulate over time and become clinically relevant once a critical amount of nerve fascicles is affected. Moreover, MRN is an objective method for determining lower function mainly in medium and large fibers in DPN.
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Affiliation(s)
- Jan B Groener
- Endocrinology and Clinical Chemistry, Internal Medicine Department I, University Hospital Heidelberg, Heidelberg, Germany
- Deutsches Zentrum für Diabetesforschung (DZD) e.V., München-Neuherberg, Germany
- Medicover Neuroendokrinologie, Munich, Germany
| | - Johann M E Jende
- Neuroradiology, Department of Neurology, University Hospital Heidelberg, Heidelberg, Germany
| | - Felix T Kurz
- Neuroradiology, Department of Neurology, University Hospital Heidelberg, Heidelberg, Germany
| | - Zoltan Kender
- Endocrinology and Clinical Chemistry, Internal Medicine Department I, University Hospital Heidelberg, Heidelberg, Germany
- Deutsches Zentrum für Diabetesforschung (DZD) e.V., München-Neuherberg, Germany
| | - Rolf-Detlef Treede
- Department of Neurophysiology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Sigrid Schuh-Hofer
- Department of Neurophysiology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Peter P Nawroth
- Endocrinology and Clinical Chemistry, Internal Medicine Department I, University Hospital Heidelberg, Heidelberg, Germany
- Deutsches Zentrum für Diabetesforschung (DZD) e.V., München-Neuherberg, Germany
- Joint Heidelberg-ICD Translational Diabetes Program, Helmoltz-Zentrum, Munich, Germany
| | - Martin Bendszus
- Neuroradiology, Department of Neurology, University Hospital Heidelberg, Heidelberg, Germany
| | - Stefan Kopf
- Endocrinology and Clinical Chemistry, Internal Medicine Department I, University Hospital Heidelberg, Heidelberg, Germany
- Deutsches Zentrum für Diabetesforschung (DZD) e.V., München-Neuherberg, Germany
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Sun X, Pan X, Ni K, Ji C, Wu J, Yan C, Luo Y. Aberrant Thalamic-Centered Functional Connectivity in Patients with Persistent Somatoform Pain Disorder. Neuropsychiatr Dis Treat 2020; 16:273-281. [PMID: 32158212 PMCID: PMC6986177 DOI: 10.2147/ndt.s231555] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 01/11/2020] [Indexed: 12/26/2022] Open
Abstract
PURPOSE Recent task-based fMRI studies have shown that Persistent Somatoform Pain Disorder (PSPD) patients demonstrated aberrant activity in a wide range of brain regions associated with sensation, cognition and emotion. However, these specific task-based studies could not clearly uncover the alterations in the spontaneous brain networks that were associated with the general pain-related symptoms in PSPD. PATIENTS AND METHODS In the present study, 13 PSPD patients and 23 matched healthy controls (HCs) were enrolled. Resting state and 3D structural imaging data were collected during magnetic resonance imaging (MRI) scans. Ninety regions of interest (ROIs) were selected from the automated anatomical labeling (AAL) template. The functional connectivity toolbox "CONN" was used to calculate the functional connectivity (FC) coefficients. RESULTS Our results showed that PSPD patients exhibited increased FCs between the left thalamus and the right amygdala, the right hippocampus, and multiple sub-regions of the occipital lobe when compared to HCs. Correlation analysis revealed a negative correlation between the left thalamus-right amygdala FC and the level of anxiety in PSPD patients. CONCLUSION These findings suggest that the altered FC between thalamus and amygdala may be the neural mechanisms underlying the pain-related anxiety in PSPD.
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Affiliation(s)
- Xia Sun
- Department of Psychological Medicine, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Xiandi Pan
- Shanghai Pudong New Area Mental Health Center, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Kaiji Ni
- Department of Psychological Medicine, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Chenfeng Ji
- Department of Psychological Medicine, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Jiaxin Wu
- Department of Psychiatry, Tongji Hospital of Tongji University, Shanghai, People's Republic of China
| | - Chao Yan
- Key Laboratory of Brain Functional Genomics (MOE&STCSM), Shanghai Changning-ECNU Mental Health Center, School of Psychology and Cognitive Science, East China Normal University, Shanghai, People's Republic of China
| | - Yanli Luo
- Department of Psychological Medicine, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
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Shillo P, Sloan G, Greig M, Hunt L, Selvarajah D, Elliott J, Gandhi R, Wilkinson ID, Tesfaye S. Painful and Painless Diabetic Neuropathies: What Is the Difference? Curr Diab Rep 2019; 19:32. [PMID: 31065863 PMCID: PMC6505492 DOI: 10.1007/s11892-019-1150-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW The prevalence of diabetes mellitus and its chronic complications are increasing to epidemic proportions. This will unfortunately result in massive increases in diabetic distal symmetrical polyneuropathy (DPN) and its troublesome sequelae, including disabling neuropathic pain (painful-DPN), which affects around 25% of patients with diabetes. Why these patients develop neuropathic pain, while others with a similar degree of neuropathy do not, is not clearly understood. This review will look at recent advances that may shed some light on the differences between painful and painless-DPN. RECENT FINDINGS Gender, clinical pain phenotyping, serum biomarkers, brain imaging, genetics, and skin biopsy findings have been reported to differentiate painful- from painless-DPN. Painful-DPN seems to be associated with female gender and small fiber dysfunction. Moreover, recent brain imaging studies have found neuropathic pain signatures within the central nervous system; however, whether this is the cause or effect of the pain is yet to be determined. Further research is urgently required to develop our understanding of the pathogenesis of pain in DPN in order to develop new and effective mechanistic treatments for painful-DPN.
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Affiliation(s)
- Pallai Shillo
- Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Glossop Road, Sheffield, S10 2JF UK
| | - Gordon Sloan
- Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Glossop Road, Sheffield, S10 2JF UK
| | - Marni Greig
- Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Glossop Road, Sheffield, S10 2JF UK
| | - Leanne Hunt
- Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Glossop Road, Sheffield, S10 2JF UK
| | - Dinesh Selvarajah
- Department of Oncology and Human Metabolism, University of Sheffield, Sheffield, UK
| | - Jackie Elliott
- Department of Oncology and Human Metabolism, University of Sheffield, Sheffield, UK
| | - Rajiv Gandhi
- Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Glossop Road, Sheffield, S10 2JF UK
| | | | - Solomon Tesfaye
- Diabetes Research Unit, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Glossop Road, Sheffield, S10 2JF UK
- Department of Oncology and Human Metabolism, University of Sheffield, Sheffield, UK
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Djouhri L, Malki MI, Zeidan A, Nagi K, Smith T. Activation of Kv7 channels with the anticonvulsant retigabine alleviates neuropathic pain behaviour in the streptozotocin rat model of diabetic neuropathy. J Drug Target 2019; 27:1118-1126. [DOI: 10.1080/1061186x.2019.1608552] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Laiche Djouhri
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Mohammed Imad Malki
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Asad Zeidan
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Karim Nagi
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Trevor Smith
- Department of Medical Physics & Biomedical Engineering, University College London, London, UK
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Rajchgot T, Thomas SC, Wang JC, Ahmadi M, Balood M, Crosson T, Dias JP, Couture R, Claing A, Talbot S. Neurons and Microglia; A Sickly-Sweet Duo in Diabetic Pain Neuropathy. Front Neurosci 2019; 13:25. [PMID: 30766472 PMCID: PMC6365454 DOI: 10.3389/fnins.2019.00025] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 01/11/2019] [Indexed: 12/11/2022] Open
Abstract
Diabetes is a common condition characterized by persistent hyperglycemia. High blood sugar primarily affects cells that have a limited capacity to regulate their glucose intake. These cells include capillary endothelial cells in the retina, mesangial cells in the renal glomerulus, Schwann cells, and neurons of the peripheral and central nervous systems. As a result, hyperglycemia leads to largely intractable complications such as retinopathy, nephropathy, hypertension, and neuropathy. Diabetic pain neuropathy is a complex and multifactorial disease that has been associated with poor glycemic control, longer diabetes duration, hypertension, advanced age, smoking status, hypoinsulinemia, and dyslipidemia. While many of the driving factors involved in diabetic pain are still being investigated, they can be broadly classified as either neuron -intrinsic or -extrinsic. In neurons, hyperglycemia impairs the polyol pathway, leading to an overproduction of reactive oxygen species and reactive nitrogen species, an enhanced formation of advanced glycation end products, and a disruption in Na+/K+ ATPase pump function. In terms of the extrinsic pathway, hyperglycemia leads to the generation of both overactive microglia and microangiopathy. The former incites a feed-forward inflammatory loop that hypersensitizes nociceptor neurons, as observed at the onset of diabetic pain neuropathy. The latter reduces neurons' access to oxygen, glucose and nutrients, prompting reductions in nociceptor terminal expression and losses in sensation, as observed in the later stages of diabetic pain neuropathy. Overall, microglia can be seen as potent and long-lasting amplifiers of nociceptor neuron activity, and may therefore constitute a potential therapeutic target in the treatment of diabetic pain neuropathy.
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Affiliation(s)
- Trevor Rajchgot
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Sini Christine Thomas
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Jo-Chiao Wang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Maryam Ahmadi
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Mohammad Balood
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Théo Crosson
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Jenny Pena Dias
- Johns Hopkins University School of Medicine, Division of Endocrinology, Diabetes and Metabolism, Baltimore, MD, United States
| | - Réjean Couture
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Audrey Claing
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Sébastien Talbot
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
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13
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Sloan G, Shillo P, Selvarajah D, Wu J, Wilkinson ID, Tracey I, Anand P, Tesfaye S. A new look at painful diabetic neuropathy. Diabetes Res Clin Pract 2018; 144:177-191. [PMID: 30201394 DOI: 10.1016/j.diabres.2018.08.020] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 08/24/2018] [Indexed: 02/06/2023]
Abstract
The prevalence of diabetes mellitus and its chronic complications continue to increase alarmingly. Consequently, the massive expenditure on diabetic distal symmetrical polyneuropathy (DSPN) and its sequelae, will also likely rise. Up to 50% of patients with diabetes develop DSPN, and about 20% develop neuropathic pain (painful-DSPN). Painful-DSPN can cast a huge burden on sufferers' lives with increased rates of unemployment, mental health disorders and physical co-morbidities. Unfortunately, due to limited understanding of the mechanisms leading to painful-DSPN, current treatments remain inadequate. Recent studies examining the pathophysiology of painful-DSPN have identified maladaptive alterations at the level of both the peripheral and central nervous systems. Additionally, genetic studies have suggested that patients with variants of voltage gated sodium channels may be more at risk of developing neuropathic pain in the presence of a disease trigger such as diabetes. We review the recent advances in genetics, skin biopsy immunohistochemistry and neuro-imaging, which have the potential to further our understanding of the condition, and identify targets for new mechanism based therapies.
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Affiliation(s)
- Gordon Sloan
- Diabetes Research Unit, Sheffield Teaching Hospitals NHS Foundation Trust & Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom
| | - Pallai Shillo
- Diabetes Research Unit, Sheffield Teaching Hospitals NHS Foundation Trust & Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom
| | - Dinesh Selvarajah
- Diabetes Research Unit, Sheffield Teaching Hospitals NHS Foundation Trust & Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom
| | - Jing Wu
- Department of Endocrinology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Iain D Wilkinson
- Diabetes Research Unit, Sheffield Teaching Hospitals NHS Foundation Trust & Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom
| | - Irene Tracey
- FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Praveen Anand
- Peripheral Neuropathy Unit, Centre for Clinical Translation, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Solomon Tesfaye
- Diabetes Research Unit, Sheffield Teaching Hospitals NHS Foundation Trust & Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom.
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14
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Acute and Chronic Pain Processing in the Thalamocortical System of Humans and Animal Models. Neuroscience 2018; 387:58-71. [DOI: 10.1016/j.neuroscience.2017.09.042] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 08/24/2017] [Accepted: 09/24/2017] [Indexed: 02/07/2023]
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15
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Athie MCP, Vieira AS, Teixeira JM, dos Santos GG, Dias EV, Tambeli CH, Sartori CR, Parada CA. Transcriptome analysis of dorsal root ganglia's diabetic neuropathy reveals mechanisms involved in pain and regeneration. Life Sci 2018; 205:54-62. [DOI: 10.1016/j.lfs.2018.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/26/2018] [Accepted: 05/06/2018] [Indexed: 11/15/2022]
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16
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Nawroth PP, Bendszus M, Pham M, Jende J, Heiland S, Ries S, Schumann C, Schmelz M, Schuh-Hofer S, Treede RD, Kuner R, Oikonomou D, Groener JB, Kopf S. The Quest for more Research on Painful Diabetic Neuropathy. Neuroscience 2017; 387:28-37. [PMID: 28942323 DOI: 10.1016/j.neuroscience.2017.09.023] [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: 04/03/2017] [Revised: 08/07/2017] [Accepted: 09/12/2017] [Indexed: 01/15/2023]
Abstract
A 62-year-old diabetologist diagnosed himself to have diabetes type-2, with an HbA1c of 9.5. Five months after lifestyle intervention and a multi-drug approach, HbA1c was 6.3, systolic blood pressure was below 135mmHg and BMI reduced to 27. But he suffered from severe painful diabetic neuropathy. Therefore he decided to visit his friend, a famous neuroscientist at an even more famous university. He asked him several plain questions: 1. What is the natural course of painful diabetic neuropathy? 2. Why do I have, despite almost normalizing HbA1c, more problems than before? 3. Are you sure my problems are due to diabetes or should we do a nerve biopsy? 4. Are there imaging techniques helpful for the diagnosis of this diabetic complication, starting in the distal nerve endings of the foot and slowly moving ahead? 5. Can you suggest any drug, specific and effective, for relieving painful diabetic neuropathy? This review will use the experts' answers to the questions of the diabetologist, not only to give a summary of the current knowledge, but even more to highlight areas of research needed for improving the fate of patients with painful diabetic neuropathy. Based on the unknowns, which exceed the knowns in diabetic neuropathy, a quest for more public support of research is made.
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Affiliation(s)
- P P Nawroth
- University Hospital Heidelberg, Department of Internal Medicine 1 and Clinical Chemistry, Heidelberg, Germany; German Center for Diabetes Research (DZD), Germany; Joint Heidelberg-IDC Translational Diabetes Program, Helmholtz-Zentrum, München, Germany.
| | - M Bendszus
- University Hospital Heidelberg, Department of Neuroradiology, Heidelberg, Germany
| | - M Pham
- University Hospital Würzburg, Department of Neuroradiology, Würzburg, Germany
| | - J Jende
- University Hospital Heidelberg, Department of Neuroradiology, Heidelberg, Germany
| | - S Heiland
- University Hospital Heidelberg, Department of Neuroradiology, Heidelberg, Germany
| | - S Ries
- Neuro Centrum Odenwald, Darmstadt, Germany
| | - C Schumann
- Neuro Centrum Odenwald, Darmstadt, Germany
| | - M Schmelz
- Department of Anesthesiology and Intensive Care Medicine, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - S Schuh-Hofer
- Department of Neurophysiology, Centre of Biomedicine and Medical Technology Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - R D Treede
- Department of Neurophysiology, Centre of Biomedicine and Medical Technology Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - R Kuner
- University of Heidelberg, Institute of Pharmacology, Heidelberg, Germany
| | - D Oikonomou
- University Hospital Heidelberg, Department of Internal Medicine 1 and Clinical Chemistry, Heidelberg, Germany
| | - J B Groener
- University Hospital Heidelberg, Department of Internal Medicine 1 and Clinical Chemistry, Heidelberg, Germany; German Center for Diabetes Research (DZD), Germany
| | - S Kopf
- University Hospital Heidelberg, Department of Internal Medicine 1 and Clinical Chemistry, Heidelberg, Germany; German Center for Diabetes Research (DZD), Germany
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17
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Reed WR, Cranston JT, Onifer SM, Little JW, Sozio RS. Decreased spontaneous activity and altered evoked nociceptive response of rat thalamic submedius neurons to lumbar vertebra thrust. Exp Brain Res 2017; 235:2883-2892. [PMID: 28687855 DOI: 10.1007/s00221-017-5013-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 06/14/2017] [Indexed: 12/18/2022]
Abstract
The thalamus is a central structure important to modulating and processing all mechanoreceptor input destined for the cortex. A large number of diverse mechanoreceptor endings are stimulated when a high velocity low amplitude thrust is delivered to the lumbar spine during spinal manipulation. The objective of this study was to determine if a lumbar thrust alters spontaneous and/or evoked nociceptive activity in medial thalamic submedius (Sm) neurons. Extracellular recordings were obtained from 94 thalamic Sm neurons in 54 urethane-anesthetized adult Wistar rats. Spontaneous activity was recorded 5 min before and after an L5 control (no thrust) and thrust (85% rat body weight; 100 ms) procedure. In a subset of responsive nociceptive-specific neurons, mean changes in noxious-evoked response (10-s pinch with clip; 795 g) at three sites (tail, contra- and ipsilateral hindpaw) were determined following an L5 thrust. Mean changes in Sm spontaneous activity (60 s bins) and evoked noxious response were compared using a mixed model repeated measures ANOVA with Bonferroni post hoc t tests and paired t tests, respectively. Compared to control, spontaneous Sm activity decreased 180-240 s following the lumbar thrust (p < 0.005). Inhibitory evoked responses were attenuated in the contralateral hindpaw following an L5 thrust compared to control (p < 0.05). No other changes in spontaneous or noxious-evoked Sm activity were found. A delayed, but prolonged suppression of spontaneous Sm activity along with changes in noxious-evoked inhibitory responses in the contralateral hindpaw following lumbar vertebra thrust suggest that thalamic submedius neurons may play a role in central pain modulation related to manual therapy intervention.
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Affiliation(s)
- William R Reed
- Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, IA, USA.
- Department of Physical Therapy, School of Health Professions, UAB, The University of Alabama at Birmingham, Webb 318, 1720 2nd Avenue South, Birmingham, AL, 35294-1212, USA.
| | - Jamie T Cranston
- Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, IA, USA
| | - Stephen M Onifer
- Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, IA, USA
| | - Joshua W Little
- Department of Surgery, Center for Anatomical Science and Education, Saint Louis University School of Medicine, St. Louis, MO, USA
| | - Randall S Sozio
- Palmer Center for Chiropractic Research, Palmer College of Chiropractic, Davenport, IA, USA
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18
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Abstract
Pain is a subjective and complex phenomenon. Its complexity is related to its heterogeneity: multiple component processes, including sensation, affect, and cognition, contribute to pain experience and reporting. These components are likely to be encoded in distributed brain networks that interact to create pain experience and pain-related decision-making. Therefore, to understand pain, we must identify these networks and build models of these interactions that yield testable predictions about pain-related outcomes. We have developed several such models or 'signatures' of pain, by (1) integrating activity across multiple systems, and (2) using pattern-recognition to identify processes related to pain experience. One model, the Neurologic Pain Signature, is sensitive and specific to pain in individuals, involves brain regions that receive nociceptive afferents, and shows little effect of expectation or self-regulation in tests to date. Another, the 'Stimulus Intensity-Independent Pain Signature', explains substantial additional variation in trial-to-trial pain reports. It involves many brain regions that do not show increased activity in proportion to noxious stimulus intensity, including medial and lateral prefrontal cortex, nucleus accumbens, and hippocampus. Responses in this system mediate expectancy and perceived control effects in several studies. Overall, this approach provides a pathway to understanding pain by identifying multiple systems that track different aspects of pain. Such componential models can be combined in unique ways on a subject-by-subject basis to explain an individual's pain experience.
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Affiliation(s)
- Marianne C Reddan
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - Tor D Wager
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, CO, 80303, USA.
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19
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Feldman EL, Nave KA, Jensen TS, Bennett DLH. New Horizons in Diabetic Neuropathy: Mechanisms, Bioenergetics, and Pain. Neuron 2017; 93:1296-1313. [PMID: 28334605 PMCID: PMC5400015 DOI: 10.1016/j.neuron.2017.02.005] [Citation(s) in RCA: 541] [Impact Index Per Article: 77.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 02/02/2017] [Accepted: 02/02/2017] [Indexed: 12/13/2022]
Abstract
Pre-diabetes and diabetes are a global epidemic, and the associated neuropathic complications create a substantial burden on both the afflicted patients and society as a whole. Given the enormity of the problem and the lack of effective therapies, there is a pressing need to understand the mechanisms underlying diabetic neuropathy (DN). In this review, we present the structural components of the peripheral nervous system that underlie its susceptibility to metabolic insults and then discuss the pathways that contribute to peripheral nerve injury in DN. We also discuss systems biology insights gleaned from the recent advances in biotechnology and bioinformatics, emerging ideas centered on the axon-Schwann cell relationship and associated bioenergetic crosstalk, and the rapid expansion of our knowledge of the mechanisms contributing to neuropathic pain in diabetes. These recent advances in our understanding of DN pathogenesis are paving the way for critical mechanism-based therapy development.
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Affiliation(s)
- Eva L Feldman
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
| | - Troels S Jensen
- Department of Neurology and Danish Pain Research Center, Aarhus University, 8000 Aarhus C, Denmark
| | - David L H Bennett
- Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX3 9DU, UK
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20
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Chundi V, Challa SR, Garikapati DR, Juvva G, Jampani A, Pinnamaneni SH, Venigalla S. Biochanin-A attenuates neuropathic pain in diabetic rats. J Ayurveda Integr Med 2016; 7:231-237. [PMID: 27890700 PMCID: PMC5192256 DOI: 10.1016/j.jaim.2016.08.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 08/13/2016] [Accepted: 08/15/2016] [Indexed: 11/30/2022] Open
Abstract
Background Soya supplements are used in the treatment of neuropathic pain. Previous reports reveal that consumption of soy diet before nerve injury prevents the development of neuropathic pain in rats. Biochanin-A, a soy isoflavone, has a naturally occurring inhibitor of fatty acid amide hydrolase (FAAH) that metabolized endocannabinoids. Objective The objective was to evaluate efficacy of biochanin-A in streptozotocin (STZ) induced neuropathic pain in rat model. Materials and methods Diabetes mellitus was induced by an injection of STZ at a dose of 45 mg/kg, i.v. into tail vein of male albino Wistar rats. Biochanin-A was dosed at 0.1, 1 and 5 mg/kg by intraperitoneal (i.p.) administration in diabetic neuropathic rats. Mechanical hyperalgesia and allodynia was measured using Randall–Selitto analgesymeter and manual von Frey filaments of increasing weights respectively. Paw withdrawal threshold (PWT) and percent PWT was determined with respect to both hyperalgesia and allodynia. Results Treatment of biochanin-A at three different levels of 0.1, 1 and 5 mg/kg had not significantly altered serum glucose levels throughout the treatment period. In hyperalgesia study, acute treatment with higher dose exhibited 51.1% reversal of paw withdrawal threshold (PWT) while with chronic treatment, efficacy declined to 22.5% reversal of PWT. In allodynia study, acute treatment reversed PWT by 79.4% while with chronic treatment, efficacy was raised to 88.2% reversal of PWT. Conclusion Biochanin-A demonstrated better efficacy in reversing mechanical allodynia than mechanical hyperalgesia. Biochanin-A could be a good drug candidate for further studies to establish the mechanism of attenuation of neuropathic pain.
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Affiliation(s)
- Venkateswarlu Chundi
- Department of Zoology, PB Siddhartha College of Arts & Science, Siddhartha Nagar, Vijayawada 520010, Andhra Pradesh, India
| | - Siva Reddy Challa
- Department of Pharmacology, KVSR Siddhartha College of Pharmaceutical Sciences, Vijayawada 520010, Andhra Pradesh, India.
| | - Devala Rao Garikapati
- Department of Pharmacology, KVSR Siddhartha College of Pharmaceutical Sciences, Vijayawada 520010, Andhra Pradesh, India
| | - Giridhar Juvva
- Department of Pharmacology, KVSR Siddhartha College of Pharmaceutical Sciences, Vijayawada 520010, Andhra Pradesh, India
| | - Anusha Jampani
- Department of Pharmacology, KVSR Siddhartha College of Pharmaceutical Sciences, Vijayawada 520010, Andhra Pradesh, India
| | - Sree Harsha Pinnamaneni
- Department of Pharmacology, KVSR Siddhartha College of Pharmaceutical Sciences, Vijayawada 520010, Andhra Pradesh, India
| | - Sahithi Venigalla
- Department of Pharmacology, KVSR Siddhartha College of Pharmaceutical Sciences, Vijayawada 520010, Andhra Pradesh, India
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21
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Tesfaye S, Selvarajah D, Gandhi R, Greig M, Shillo P, Fang F, Wilkinson ID. Diabetic peripheral neuropathy may not be as its name suggests: evidence from magnetic resonance imaging. Pain 2016; 157 Suppl 1:S72-S80. [PMID: 26785159 DOI: 10.1097/j.pain.0000000000000465] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Diabetic peripheral neuropathy (DPN) affects up to 50% of patients with diabetes and is a major cause of morbidity and increased mortality. Its clinical manifestations include distressing painful neuropathic symptoms and insensitivity to trauma that result in foot ulcerations and amputations. Several recent studies have implicated poor glycemic control, duration of diabetes, hyperlipidemia (particularly hypertryglyceridaemia), elevated albumin excretion rates, and obesity as risk factors for the development of DPN. However, similar data are not available for painful DPN. Moreover, although there is now strong evidence for the importance of peripheral nerve microvascular disease in the pathogenesis of DPN, peripheral structural biomarkers of painful DPN are lacking. However, there is now emerging evidence for the involvement of the central nervous system in both painful and painless DPN afforded by magnetic resonance imaging. This review will focus on this emerging evidence for central changes in DPN, hitherto considered a peripheral nerve disease only.
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Affiliation(s)
- Solomon Tesfaye
- Diabetes Research Unit, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom Department of Human Metabolism Unit, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom Academic Unit of Radiology, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, United Kingdom
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22
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Pain modulation from the brain during diabetic neuropathy: Uncovering the role of the rostroventromedial medulla. Neurobiol Dis 2016; 96:346-356. [PMID: 27717882 DOI: 10.1016/j.nbd.2016.10.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 09/06/2016] [Accepted: 10/01/2016] [Indexed: 01/17/2023] Open
Abstract
Diabetic neuropathy has a profound impact in the quality of life of patients who frequently complain of pain. The mechanisms underlying diabetic neuropathic pain (DNP) are no longer ascribed only to damage of peripheral nerves. The effects of diabetes at the central nervous system are currently considered causes of DPN. Management of DNP may be achieved by antidepressants that act on serotonin (5-HT) uptake, namely specific serotonin reuptake inhibitors. The rostroventromedial medulla (RVM) is a key pain control center involved in descending pain modulation at the spinal cord through local release of 5-HT and plays a peculiar role in the balance of bidirectional control (i.e. inhibitory and facilitatory) from the brain to the spinal cord. This review discusses recently uncovered neurobiological mechanisms that mediate nociceptive modulation from the RVM during diabetes installation. In early phases of the disease, facilitation of pain modulation from the RVM prevails through a triplet of mechanisms which include increase in serotonin expression at the RVM and consequent rise of serotonin levels at the spinal cord and upregulation of local facilitatory 5HT3 receptors, enhancement of spontaneous activity of facilitatory RVM neurons and up-regulation of the expression of transient receptor potential vanilloid type 1 (TRPV1) receptor. With the progression of diabetes the alterations in the RVM increase dramatically, with oxidative stress and neuronal death associated to microglia-mediated inflammation. In a manner similar to other central areas, like the thalamus, the RVM is likely to be a "pain generator/amplifier" during diabetes, accounting to increase DNP. Early interventions in DNP prevention using strategies that simultaneously tackle the exacerbation of 5-HT3 spinal receptors and of microglial RVM activity, namely those that increase the levels of anti-inflammatory cytokines, should be considered in the future of DNP treatment.
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23
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Greig M, Tesfaye S, Selvarajah D, Wilkinson ID. Insights into the pathogenesis and treatment of painful diabetic neuropathy. HANDBOOK OF CLINICAL NEUROLOGY 2016; 126:559-78. [PMID: 25410244 DOI: 10.1016/b978-0-444-53480-4.00037-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Painful diabetic distal symmetrical polyneuropathy (painful DPN) is a puzzle with two important missing pieces: Firstly we still do not understand why only some patients with neuropathy experience painful symptoms; Secondly we still do not have a complete understanding of how nociception generated in the peripheral nervous system is processed by the central nervous system (CNS). Available treatments offer only symptom relief and there is currently no effective treatment based on arresting or reversing the progression of disease. Therefore the management of painful DPN remains less than optimal because the complex pathophysiology of nociception and pain perception in health and disease is incompletely understood. Studies of the peripheral nervous system are investigating the molecular processes involved in signal transduction that have the potential to be interrupted or modified to ease pain. Magnetic resonance imaging techniques are helping to elucidate central pain processing pathways and describe the translation of nociception to pain. Combining the knowledge from these two streams of enquiry we will soon be able to predict accurately who will develop painful DPN, how we can halt or reverse the condition, or who will respond to symptomatic treatments. Future developments in the treatment of painful DPN will be underpinned by decoding the peripheral and central mechanisms of pain. Research is focusing on these areas of enquiry in the hope that answers will lead to effective treatments to alleviate pain and reverse pathology for those suffering from painful DPN.
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Affiliation(s)
- Marni Greig
- Diabetes Department, Royal Hallamshire Hospital, Sheffield, UK
| | - Solomon Tesfaye
- Diabetes Department, Royal Hallamshire Hospital, Sheffield, UK.
| | | | - Iain D Wilkinson
- Academic Radiology, Department of Cardiovascular Science, Royal Hallamshire Hospital, Sheffield, UK
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24
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Abstract
Painful neuropathy, like the other complications of diabetes, is a growing healthcare concern. Unfortunately, current treatments are of variable efficacy and do not target underlying pathogenic mechanisms, in part because these mechanisms are not well defined. Rat and mouse models of type 1 diabetes are frequently used to study diabetic neuropathy, with rats in particular being consistently reported to show allodynia and hyperalgesia. Models of type 2 diabetes are being used with increasing frequency, but the current literature on the progression of indices of neuropathic pain is variable and relatively few therapeutics have yet been developed in these models. While evidence for spontaneous pain in rodent models is sparse, measures of evoked mechanical, thermal and chemical pain can provide insight into the pathogenesis of the condition. The stocking and glove distribution of pain tantalizingly suggests that the generator site of neuropathic pain is found within the peripheral nervous system. However, emerging evidence demonstrates that amplification in the spinal cord, via spinal disinhibition and neuroinflammation, and also in the brain, via enhanced thalamic activity or decreased cortical inhibition, likely contribute to the pathogenesis of painful diabetic neuropathy. Several potential therapeutic strategies have emerged from preclinical studies, including prophylactic treatments that intervene against underlying mechanisms of disease, treatments that prevent gains of nociceptive function, treatments that suppress enhancements of nociceptive function, and treatments that impede normal nociceptive mechanisms. Ongoing challenges include unraveling the complexity of underlying pathogenic mechanisms, addressing the potential disconnect between the perceived location of pain and the actual pain generator and amplifier sites, and finding ways to identify which mechanisms operate in specific patients to allow rational and individualized choice of targeted therapies.
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Affiliation(s)
- Corinne A Lee-Kubli
- Graduate School of Biomedical Sciences, Sanford-Burnham Institute for Molecular Medicine, La Jolla, CA, USA; 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.
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25
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Freeman OJ, Evans MH, Cooper GJS, Petersen RS, Gardiner NJ. Thalamic amplification of sensory input in experimental diabetes. Eur J Neurosci 2016; 44:1779-86. [PMID: 27152754 PMCID: PMC4950294 DOI: 10.1111/ejn.13267] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 04/13/2016] [Accepted: 05/04/2016] [Indexed: 12/29/2022]
Abstract
Diabetic neuropathy is a common, and often debilitating, secondary complication of diabetes mellitus. As pain, hypersensitivity and paraesthesias present in a distal-proximal distribution, symptoms are generally believed to originate from damaged afferents within the peripheral nervous system. Increasing evidence suggests altered processing within the central nervous system in diabetic neuropathy contributes towards somatosensory dysfunction, but whether the accurate coding and relay of peripherally encoded information through the central nervous system is altered in diabetes is not understood. Here, we applied the strengths of the rodent whisker-barrel system to study primary afferent-thalamic processing in diabetic neuropathy. We found that neurons in the thalamic ventral posteromedial nucleus from rats with experimental diabetic neuropathy showed increased firing to precisely graded, multidirectional whisker deflection compared to non-diabetic rats. This thalamic hyperactivity occurred without any overt primary afferent dysfunction, as recordings from the trigeminal ganglion showed these primary afferents to be unaffected by diabetes. These findings suggest that central amplification can substantially transform ascending sensory input in diabetes, even in the absence of a barrage of ectopic primary afferent activity.
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Affiliation(s)
- Oliver J Freeman
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Mathew H Evans
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Garth J S Cooper
- Centre for Advanced Discovery and Experimental Therapeutics (CADET), Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, UK.,Centre for Endocrinology and Diabetes, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK.,School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Medical Sciences Division, Department of Pharmacology, University of Oxford, Oxford, UK
| | - Rasmus S Petersen
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
| | - Natalie J Gardiner
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK
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Patel R, Dickenson AH. Neuronal hyperexcitability in the ventral posterior thalamus of neuropathic rats: modality selective effects of pregabalin. J Neurophysiol 2016; 116:159-70. [PMID: 27098028 PMCID: PMC4961752 DOI: 10.1152/jn.00237.2016] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 04/20/2016] [Indexed: 01/25/2023] Open
Abstract
Studies on brain mechanisms of neuropathic pain are lacking. This study characterizes the properties of rat ventral posterior thalamic wide dynamic range (WDR) and nociceptive-specific (NS) neurons, the latter of which are uncharacterized in a neuropathic state. We provide evidence of phenotypic changes in neuronal sensitivity that may underlie cold and brush hypersensitivity, and that WDR neurons, and not NS neurons, encode hypersensitivity to low-intensity stimuli. Pregabalin reversed neuronal hyperexcitability in spinal nerve-ligated rats in a modality-selective manner. Neuropathic pain represents a substantial clinical challenge; understanding the underlying neural mechanisms and back-translation of therapeutics could aid targeting of treatments more effectively. The ventral posterior thalamus (VP) is the major termination site for the spinothalamic tract and relays nociceptive activity to the somatosensory cortex; however, under neuropathic conditions, it is unclear how hyperexcitability of spinal neurons converges onto thalamic relays. This study aimed to identify neural substrates of hypersensitivity and the influence of pregabalin on central processing. In vivo electrophysiology was performed to record from VP wide dynamic range (WDR) and nociceptive-specific (NS) neurons in anesthetized spinal nerve-ligated (SNL), sham-operated, and naive rats. In neuropathic rats, WDR neurons had elevated evoked responses to low- and high-intensity punctate mechanical stimuli, dynamic brushing, and innocuous and noxious cooling, but less so to heat stimulation, of the receptive field. NS neurons in SNL rats also displayed increased responses to noxious punctate mechanical stimulation, dynamic brushing, noxious cooling, and noxious heat. Additionally, WDR, but not NS, neurons in SNL rats exhibited substantially higher rates of spontaneous firing, which may correlate with ongoing pain. The ratio of WDR-to-NS neurons was comparable between SNL and naive/sham groups, suggesting relatively few NS neurons gain sensitivity to low-intensity stimuli leading to a “WDR phenotype.” After neuropathy was induced, the proportion of cold-sensitive WDR and NS neurons increased, supporting the suggestion that changes in frequency-dependent firing and population coding underlie cold hypersensitivity. In SNL rats, pregabalin inhibited mechanical and heat responses but not cold-evoked or elevated spontaneous activity.
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Affiliation(s)
- Ryan Patel
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Anthony H Dickenson
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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Zhao P, Hill M, Liu S, Chen L, Bangalore L, Waxman SG, Tan AM. Dendritic spine remodeling following early and late Rac1 inhibition after spinal cord injury: evidence for a pain biomarker. J Neurophysiol 2016; 115:2893-910. [PMID: 26936986 DOI: 10.1152/jn.01057.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/01/2016] [Indexed: 12/15/2022] Open
Abstract
Neuropathic pain is a significant complication following spinal cord injury (SCI) with few effective treatments. Drug development for neuropathic pain often fails because preclinical studies do not always translate well to clinical conditions. Identification of biological characteristics predictive of disease state or drug responsiveness could facilitate more effective clinical translation. Emerging evidence indicates a strong correlation between dendritic spine dysgenesis and neuropathic pain. Because dendritic spines are located on dorsal horn neurons within the spinal cord nociceptive system, dendritic spine remodeling provides a unique opportunity to understand sensory dysfunction after SCI. In this study, we provide support for the postulate that dendritic spine profiles can serve as biomarkers for neuropathic pain. We show that dendritic spine profiles after SCI change to a dysgenic state that is characteristic of neuropathic pain in a Rac1-dependent manner. Suppression of the dysgenic state through inhibition of Rac1 activity is accompanied by attenuation of neuropathic pain. Both dendritic spine dysgenesis and neuropathic pain return when inhibition of Rac1 activity is lifted. These findings suggest the utility of dendritic spines as structural biomarkers for neuropathic pain.
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Affiliation(s)
- Peng Zhao
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Myriam Hill
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Shujun Liu
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Lubin Chen
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Lakshmi Bangalore
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Stephen G Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Andrew M Tan
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
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Pathophysiological implication of CaV3.1 T-type Ca2+ channels in trigeminal neuropathic pain. Proc Natl Acad Sci U S A 2016; 113:2270-5. [PMID: 26858455 DOI: 10.1073/pnas.1600418113] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A crucial pathophysiological issue concerning central neuropathic pain is the modification of sensory processing by abnormally increased low-frequency brain rhythms. Here we explore the molecular mechanisms responsible for such abnormal rhythmicity and its relation to neuropathic pain syndrome. Toward this aim, we investigated the behavioral and electrophysiological consequences of trigeminal neuropathic pain following infraorbital nerve ligations in CaV3.1 T-type Ca(2+) channel knockout and wild-type mice. CaV3.1 knockout mice had decreased mechanical hypersensitivity and reduced low-frequency rhythms in the primary somatosensory cortex and related thalamic nuclei than wild-type mice. Lateral inhibition of gamma rhythm in primary somatosensory cortex layer 4, reflecting intact sensory contrast, was present in knockout mice but severely impaired in wild-type mice. Moreover, cross-frequency coupling between low-frequency and gamma rhythms, which may serve in sensory processing, was pronounced in wild-type mice but not in CaV3.1 knockout mice. Our results suggest that the presence of CaV3.1 channels is a key element in the pathophysiology of trigeminal neuropathic pain.
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Tan AM, Samad OA, Dib-Hajj SD, Waxman SG. Virus-Mediated Knockdown of Nav1.3 in Dorsal Root Ganglia of STZ-Induced Diabetic Rats Alleviates Tactile Allodynia. Mol Med 2015; 21:544-52. [PMID: 26101954 DOI: 10.2119/molmed.2015.00063] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 06/16/2015] [Indexed: 11/06/2022] Open
Abstract
Diabetic neuropathic pain affects a substantial number of people and represents a major public health problem. Available clinical treatments for diabetic neuropathic pain remain only partially effective and many of these treatments carry the burden of side effects or the risk of dependence. The misexpression of sodium channels within nociceptive neurons contributes to abnormal electrical activity associated with neuropathic pain. Voltage-gated sodium channel Nav1.3 produces tetrodotoxin-sensitive sodium currents with rapid repriming kinetics and has been shown to contribute to neuronal hyperexcitability and ectopic firing in injured neurons. Suppression of Nav1.3 activity can attenuate neuropathic pain induced by peripheral nerve injury. Previous studies have shown that expression of Nav1.3 is upregulated in dorsal root ganglion (DRG) neurons of diabetic rats that exhibit neuropathic pain. Here, we hypothesized that viral-mediated knockdown of Nav1.3 in painful diabetic neuropathy would reduce neuropathic pain. We used a validated recombinant adeno-associated virus (AAV)-shRNA-Nav1.3 vector to knockdown expression of Nav1.3, via a clinically applicable intrathecal injection method. Three weeks following vector administration, we observed a significant rate of transduction in DRGs of diabetic rats that concomitantly reduced neuronal excitability of dorsal horn neurons and reduced behavioral evidence of tactile allodynia. Taken together, these findings offer a novel gene therapy approach for addressing chronic diabetic neuropathic pain.
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Affiliation(s)
- Andrew M Tan
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, United States of America; and Center for Neuroscience and Regeneration Research, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, United States of America
| | - Omar A Samad
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, United States of America; and Center for Neuroscience and Regeneration Research, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, United States of America
| | - Sulayman D Dib-Hajj
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, United States of America; and Center for Neuroscience and Regeneration Research, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, United States of America
| | - Stephen G Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, United States of America; and Center for Neuroscience and Regeneration Research, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, United States of America
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Tan AM. Dendritic spine dysgenesis in neuropathic pain. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 131:385-408. [PMID: 25744680 DOI: 10.1016/bs.pmbts.2014.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The failure of neuropathic pain to abate even years after trauma suggests that adverse changes to synaptic function must exist in a chronic pathological state in nociceptive pathways. The chronicity of neuropathic pain therefore underscores the importance of understanding the contribution of dendritic spines--micron-sized postsynaptic structures that represent modifiable sites of synaptic contact. Historically, dendritic spines have been of great interest to the learning and memory field. More recent evidence points to the exciting implication that abnormal dendritic spine structure following disease or injury may represent a "molecular memory" for maintaining chronic pain. Dendritic spine dysgenesis in dorsal horn neurons contributes to nociceptive hyperexcitability associated with neuropathic pain, as demonstrated in multiple pain models, i.e., spinal cord injury, peripheral nerve injury, diabetic neuropathy, and thermal burn injury. Because of the relationship between dendritic spine structure and neuronal function, a thorough investigation of dendritic spine behavior in the spinal cord is a unique opportunity to better understand the mechanisms of sensory dysfunction after injury or disease. At a conceptual level, a spinal memory mechanism that engages dendritic spine remodeling would also contribute to a broad range of intractable neurological conditions. Molecules involved in regulating dendritic spine plasticity may offer novel targets for the development of effective and durable therapies for neurological disease.
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Affiliation(s)
- Andrew Michael Tan
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA; Hopkins School, New Haven, Connecticut, USA.
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Raposo D, Morgado C, Pereira-Terra P, Tavares I. Nociceptive spinal cord neurons of laminae I-III exhibit oxidative stress damage during diabetic neuropathy which is prevented by early antioxidant treatment with epigallocatechin-gallate (EGCG). Brain Res Bull 2014; 110:68-75. [PMID: 25522867 DOI: 10.1016/j.brainresbull.2014.12.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 12/05/2014] [Accepted: 12/08/2014] [Indexed: 12/20/2022]
Abstract
Spinal cord neurons located in laminae I-III respond to nociceptive stimuli and participate in the transmission of painful information to the brain. In the present study we evaluated if nociceptive laminae I-III neurons are affected by oxidative stress damage in a model of diabetic neuropathic pain (DNP), the streptozotocin-induced diabetic rat (STZ rat). Additionally, we evaluated the effects of a preventive antioxidant treatment with epigallocatechin-gallate (EGCG) in nociceptive neuronal activation and behavioural signs of DNP. Three days after diabetes induction, a treatment protocol of STZ rats with an aqueous solution of EGCG in the drinking water was initiated. Ten weeks after the onset of treatment, the spinal cords were immunoreacted against validated markers of oxidative stress damage (8-hydroxy-2'-deoxyguanosine; 8-OHdG) and of nociceptive neuronal activation (Fos). Mechanical hypersensitivity was assessed before and after EGCG treatment. Untreated STZ rats presented increased levels of 8-OHdG immunoreaction, higher numbers of Fos-immunoreacted neurons and high levels of co-localization of 8-OHdG and Fos in laminae I-III. Treatment with EGCG normalized the increase of the above mentioned parameters and ameliorated mechanical hypersensitivity. The present study shows that nociceptive neurons in spinal cord laminae I-III exhibit oxidative stress damage during diabetic neuropathy, which probably affects ascending pain transmission during DNP. The neurobiological mechanisms and translational perspectives of the beneficial effects of a preventive and sustained EGCG treatment in DNP need to be evaluated in the future.
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Affiliation(s)
- D Raposo
- Department of Experimental Biology, Faculty of Medicine, University of Porto, Portugal; IBMC, University of Porto, Portugal
| | - C Morgado
- Department of Experimental Biology, Faculty of Medicine, University of Porto, Portugal; IBMC, University of Porto, Portugal
| | - P Pereira-Terra
- Department of Experimental Biology, Faculty of Medicine, University of Porto, Portugal; IBMC, University of Porto, Portugal
| | - I Tavares
- Department of Experimental Biology, Faculty of Medicine, University of Porto, Portugal; IBMC, University of Porto, Portugal.
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Reed WR, Sozio R, Pickar JG, Onifer SM. Effect of spinal manipulation thrust duration on trunk mechanical activation thresholds of nociceptive-specific lateral thalamic neurons. J Manipulative Physiol Ther 2014; 37:552-60. [PMID: 25220757 DOI: 10.1016/j.jmpt.2014.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 07/23/2014] [Accepted: 07/23/2014] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The objective of this preliminary study was to determine if high-velocity, low-amplitude spinal manipulation (HVLA-SM) thrust duration alters mechanical trunk activation thresholds of nociceptive-specific (NS) lateral thalamic neurons. METHODS Extracellular recordings were obtained from 18 NS neurons located in 2 lateral thalamic nuclei (ventrolateral [n = 12] and posterior [n = 6]) in normal anesthetized Wistar rats. Response thresholds to electronic von Frey anesthesiometer (rigid tip) mechanical trunk stimuli applied in 3 lumbar directions (dorsal-ventral, 45° caudal, and 45° cranial) were determined before and immediately after the delivery of 3 HVLA-SM thrust durations (time control 0, 100, and 400 milliseconds). Mean changes in mechanical trunk activation thresholds were compared using a mixed model analysis of variance. RESULTS High-velocity, low-amplitude spinal manipulation duration did not significantly alter NS lateral thalamic neurons' mechanical trunk responses to any of the 3 directions tested with the anesthesiometer. CONCLUSIONS This study is the first to examine the effect of HVLA-SM thrust duration on NS lateral thalamic mechanical response thresholds. High-velocity, low-amplitude spinal manipulation thrust duration did not affect mechanical trunk thresholds.
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Affiliation(s)
- William R Reed
- Associate Professor, Palmer Center for Chiropractic Research, Davenport, IA.
| | - Randall Sozio
- Research Associate, Palmer Center for Chiropractic Research, Davenport, IA
| | - Joel G Pickar
- Professor Emeritus, Palmer Center for Chiropractic Research, Davenport, IA
| | - Stephen M Onifer
- Associate Professor, Palmer Center for Chiropractic Research, Davenport, IA
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Pathogenesis of painful diabetic neuropathy. PAIN RESEARCH AND TREATMENT 2014; 2014:412041. [PMID: 24891949 PMCID: PMC4026988 DOI: 10.1155/2014/412041] [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: 02/04/2014] [Revised: 03/31/2014] [Accepted: 04/15/2014] [Indexed: 12/13/2022]
Abstract
The prevalence of diabetes is rising globally and, as a result, its associated complications are also rising. Painful diabetic neuropathy (PDN) is a well-known complication of diabetes and the most common cause of all neuropathic pain. About one-third of all diabetes patients suffer from PDN. It has a huge effect on a person's daily life, both physically and mentally. Despite huge advances in diabetes and neurology, the exact mechanism of pain causation in PDN is still not clear. The origin of pain could be in the peripheral nerves of the central nervous system. In this review, we discuss various possible mechanisms of the pathogenesis of pain in PDN. We discuss the role of hyperglycaemia in altering the physiology of peripheral nerves. We also describe central mechanisms of pain.
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Gustin SM, Wrigley PJ, Youssef AM, McIndoe L, Wilcox SL, Rae CD, Edden RAE, Siddall PJ, Henderson LA. Thalamic activity and biochemical changes in individuals with neuropathic pain after spinal cord injury. Pain 2014; 155:1027-1036. [PMID: 24530612 DOI: 10.1016/j.pain.2014.02.008] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 02/05/2014] [Accepted: 02/07/2014] [Indexed: 10/25/2022]
Abstract
There is increasing evidence relating thalamic changes to the generation and/or maintenance of neuropathic pain. We have recently reported that neuropathic orofacial pain is associated with altered thalamic anatomy, biochemistry, and activity, which may result in disturbed thalamocortical oscillatory circuits. Despite this evidence, it is possible that these thalamic changes are not responsible for the presence of pain per se, but result as a consequence of the injury. To clarify this subject, we compared brain activity and biochemistry in 12 people with below-level neuropathic pain after complete thoracic spinal cord injury with 11 people with similar injuries and no neuropathic pain and 21 age- and gender-matched healthy control subjects. Quantitative arterial spinal labelling was used to measure thalamic activity, and magnetic resonance spectroscopy was used to determine changes in neuronal variability quantifying N-acetylaspartate and alterations in inhibitory function quantifying gamma amino butyric acid. This study revealed that the presence of neuropathic pain is associated with significant changes in thalamic biochemistry and neuronal activity. More specifically, the presence of neuropathic pain after spinal cord injury is associated with significant reductions in thalamic N-acetylaspartate, gamma amino butyric acid content, and blood flow in the region of the thalamic reticular nucleus. Spinal cord injury on its own did not account for these changes. These findings support the hypothesis that neuropathic pain is associated with altered thalamic structure and function, which may disturb central processing and play a key role in the experience of neuropathic pain.
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Affiliation(s)
- S M Gustin
- Pain Management Research Institute, Kolling Institute of Medical Research, University of Sydney, Royal North Shore Hospital, St. Leonards, New South Wales, Australia Department of Anatomy and Histology, University of Sydney, Sydney, New South Wales, Australia Neuroscience Research Australia, Randwick, NSW 2031, Australia Sydney Medical School-Northern, University of Sydney, Sydney, New South Wales, Australia Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA F.M. Kirby Research Center for Functional MRI, Baltimore, MD, USA Department of Pain Management, HammondCare, Greenwich Hospital, Greenwich, New South Wales, Australia
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Lee-Kubli CA, Mixcoatl-Zecuatl T, Jolivalt CG, Calcutt NA. Animal models of diabetes-induced neuropathic pain. Curr Top Behav Neurosci 2014; 20:147-70. [PMID: 24510303 DOI: 10.1007/7854_2014_280] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Neuropathy will afflict over half of the approximately 350 million people worldwide who currently suffer from diabetes and around one-third of diabetic patients with neuropathy will suffer from painful symptoms that may be spontaneous or stimulus evoked. Diabetes can be induced in rats or mice by genetic, dietary, or chemical means, and there are a variety of well-characterized models of diabetic neuropathy that replicate either type 1 or type 2 diabetes. Diabetic rodents display aspects of sensorimotor dysfunction such as stimulus-evoked allodynia and hyperalgesia that are widely used to model painful neuropathy. This allows investigation of pathogenic mechanisms and development of potential therapeutic interventions that may alleviate established pain or prevent onset of pain.
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Kim YJ, Ku J, Kim HJ, Im DJ, Lee HS, Han KA, Kang YJ. Randomized, sham controlled trial of transcranial direct current stimulation for painful diabetic polyneuropathy. Ann Rehabil Med 2013; 37:766-76. [PMID: 24466511 PMCID: PMC3895516 DOI: 10.5535/arm.2013.37.6.766] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/19/2013] [Indexed: 02/04/2023] Open
Abstract
Objective To investigate the analgesic effect of transcranial direct current stimulation (tDCS) over the primary motor (M1), dorsolateral prefrontal cortex (DLPFC), and sham tDCS in patients with painful diabetic polyneuropathy (PDPN). Methods Patients with PDPN (n=60) were divided randomly into the three groups (n=20 per group). Each group received anodal tDCS with the anode centered over the left M1, DLPFC, or sham stimulation for 20 minutes at intensity of 2 mA for 5 consecutive days. A blinded physician rated the patients' pain using a visual analog scale (VAS), Clinical Global Impression (CGI) score, anxiety score, sleep quality, Beck Depression Inventory (BDI), and the pain threshold (PT) to pressure. Results After the tDCS sessions, the M1 group showed a significantly greater reduction in VAS for pain and PT versus the sham and DLPFC groups (p<0.001). The reduction in VAS for pain was sustained after 2 and 4 weeks of follow-up in the M1 group compared with the sham group (p<0.001, p=0.007). Significant differences were observed among the three groups over time in VAS for pain (p<0.001), CGI score (p=0.01), and PT (p<0.001). No significant difference was observed among the groups in sleep quality, anxiety score, or BDI score immediately after tDCS. Conclusion Five daily sessions of tDCS over the M1 can produce immediate pain relief, and relief 2- and 4-week in duration in patients with PDPN. Our findings provide the first evidence of a beneficial effect of tDCS on PDPN.
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Affiliation(s)
- Yon Joon Kim
- Department of Rehabilitation Medicine, Eulji Hospital, Eulji University School of Medicine, Seoul, Korea
| | - Jeonghun Ku
- Department of Biomedical Engineering, Keimyung University, Daegu, Korea
| | - Hyun Jung Kim
- Department of Rehabilitation Medicine, Eulji Hospital, Eulji University School of Medicine, Seoul, Korea
| | - Dal Jae Im
- Department of Rehabilitation Medicine, Eulji Hospital, Eulji University School of Medicine, Seoul, Korea
| | - Hye Sun Lee
- Department of Biostatistics, Yonsei University College of Medicine, Seoul, Korea
| | - Kyung Ah Han
- Department of Medicine, Eulji Hospital, Eulji University School of Medicine, Seoul, Korea
| | - Youn Joo Kang
- Department of Rehabilitation Medicine, Eulji Hospital, Eulji University School of Medicine, Seoul, Korea
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Burn injury-induced mechanical allodynia is maintained by Rac1-regulated dendritic spine dysgenesis. Exp Neurol 2013; 248:509-19. [DOI: 10.1016/j.expneurol.2013.07.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 07/16/2013] [Accepted: 07/26/2013] [Indexed: 11/22/2022]
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Sanoja R, Taepavarapruk N, Benda E, Tadavarty R, Soja PJ. Enhanced excitability of thalamic sensory neurons and slow-wave EEG pattern after stimuli that induce spinal long-term potentiation. J Neurosci 2013; 33:15109-19. [PMID: 24048841 PMCID: PMC6618413 DOI: 10.1523/jneurosci.2110-13.2013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/24/2013] [Accepted: 08/13/2013] [Indexed: 11/21/2022] Open
Abstract
Spinal nociceptive neurons are well known to undergo a process of long-term potentiation (LTP) following conditioning by high-frequency sciatic nerve stimulation (HFS) at intensities recruiting C-fibers. However, little if any information exists as to whether such HFS conditioning that produces spinal LTP affects sensory transmission at supraspinal levels. The present study explored this possibility. Conventional extracellular recording methods were used to examine the consequences of HFS versus sham HFS conditioning on individual wide-dynamic range thalamic neurons located in the ventro-postero-lateral (VPL) nucleus in isoflurane-anesthetized rats. Following HFS, the ongoing firing rate and stimulus-evoked (brush, pinch, sciatic nerve) responses were markedly enhanced as were responses to juxtacellular, microiontophoretic applications of glutamate. These HFS-induced enhancements lasted throughout the recording period. Sham stimuli had no effect on VPL neuron excitability. Cortical electroencephalographic (EEG) wave activities were also measured around HFS in conjunction with VPL neuron recordings. The cortical EEG pattern under baseline conditions consisted of recurring short duration bursts of high-amplitude slow waves followed by longer periods of flat EEG. Following HFS, the EEG shifted to a continuous large-amplitude, slow-wave pattern within the 0.5-8.0 Hz bandwidth lasting throughout the recording period. Sham HFS did not alter EEG activity. Sciatic nerve conditioning at A-δ fiber strength, known to reverse spinal LTP, did not alter enhanced neuronal excitability or the EEG slow-wave pattern induced by HFS. These data support the concept that HFS conditioning of the sciatic nerve, which leads to spinal LTP, is associated with distinct, long-lasting changes in the excitability of neurons comprising thalamocortical networks.
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Affiliation(s)
- Raul Sanoja
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, V6T 1Z3 Canada
| | - Niwat Taepavarapruk
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, V6T 1Z3 Canada
| | - Elke Benda
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, V6T 1Z3 Canada
| | - Ramakrishna Tadavarty
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, V6T 1Z3 Canada
| | - Peter J. Soja
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, British Columbia, V6T 1Z3 Canada
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Wilkinson ID, Selvarajah D, Greig M, Shillo P, Boland E, Gandhi R, Tesfaye S. Magnetic resonance imaging of the central nervous system in diabetic neuropathy. Curr Diab Rep 2013; 13:509-16. [PMID: 23728721 DOI: 10.1007/s11892-013-0394-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Diabetic 'peripheral' neuropathy (DPN) is one of the common sequelae to the development of both type-1 and type-2 diabetes mellitus. Neuropathy has a major negative impact on quality of life. Abnormalities in both peripheral vasculature and nerve function are well documented and, in addition, evidence is emerging regarding changes within the central nervous system (CNS) that are concomitant with the presence of DPN. The often-resistant nature of DPN to medical treatment highlights the need to understand the role of the CNS in neuropathic symptomatology and progression, as this may modulate therapeutic approaches. Advanced neuroimaging techniques, especially those that can provide quantitative measures of structure and function, can provide objective markers of CNS status. With that comes great potential for not only furthering our understanding of involvement of the CNS in neuropathic etiology but also most importantly aiding the development of new and more effective, targeted, analgesic interventions.
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Affiliation(s)
- Iain D Wilkinson
- Academic Radiology, University of Sheffield, C-Floor, Royal Hallamshire Hospital, Glossop Road, Sheffield, S10 2JF, UK.
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Abstract
Painful diabetic polyneuropathy (PDPN) is generally considered a variant of diabetic polyneuropathy (DPN) but the identification of distinctive aspects that characterize painful compared with painless DPN has however been addressed in many studies, mainly with the purpose of better understanding the mechanisms of neuropathic pain in the scenario of peripheral nerve damage of DPN, of determining risk markers for pain development, and also of recognizing who might respond to treatments. This review is aimed at examining available literature dealing with the issue of similarities and differences between painful and painless DPN in an attempt to respond to the question of whether painful and painless DPN are the same disease or not and to address the conundrum of why some people develop the insensate variety of DPN whilst others experience distressing pain. Thus, from the perspective of comparing painful with painless forms of DPN, this review considers the clinical correlates of PDPN, its distinctive framework of symptoms, signs, and nerve functional and structural abnormalities, the question of large and small fiber involvement, the peripheral pain mechanisms, the central processing of pain and some new insights into the pathogenesis of pain in peripheral polyneuropathies and PDPN.
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Affiliation(s)
- Vincenza Spallone
- Endocrinology, Department of Systems Medicine, University of Tor Vergata, Via Montpellier 1, 00133, Rome, Italy.
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Yen CT, Lu PL. Thalamus and pain. ACTA ACUST UNITED AC 2013; 51:73-80. [DOI: 10.1016/j.aat.2013.06.011] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 05/13/2013] [Indexed: 02/02/2023]
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Kwai NCG, Arnold R, Wickremaarachchi C, Lin CSY, Poynten AM, Kiernan MC, Krishnan AV. Effects of axonal ion channel dysfunction on quality of life in type 2 diabetes. Diabetes Care 2013; 36:1272-7. [PMID: 23404298 PMCID: PMC3631837 DOI: 10.2337/dc12-1310] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Pharmacological agents for diabetic peripheral neuropathy (DN) target a number of mechanisms, including sodium channel function and γ-aminobutyric acid-minergic processes. At present, prescription is undertaken on a trial-and-error basis, leading to prolonged medication trials and greater healthcare costs. Nerve-excitability techniques are a novel method of assessing axonal ion channel function in the clinical setting. The aim of this study was to determine the effects of axonal ion channel dysfunction on neuropathy-specific quality-of-life (QoL) measures in DN. RESEARCH DESIGN AND METHODS Fifty-four patients with type 2 diabetes mellitus underwent comprehensive neurologic assessment, nerve-conduction studies, and nerve-excitability assessment. Neuropathy severity was assessed using the Total Neuropathy Score. Neuropathy-specific QoL was assessed using a DN-specific QoL questionnaire (Neuropathy-Specific Quality of Life Questionnaire [NeuroQoL]). Glycosylated hemoglobin and BMI were recorded in all patients. RESULTS NeuroQoL scores indicated significant QoL impairment (mean 9.08 ± 5.93). Strength-duration time constant (SDTC), an excitability parameter reflecting sodium channel function, was strongly correlated with QoL scores (r = 0.545; P < 0.005). SDTC was prolonged in 48.6% of patients who experienced neuropathic symptoms. A significant correlation was also noted between SDTC and neuropathy severity (r = 0.29; P < 0.05). This relationship was strengthened when looking specifically at patients with clinically graded neuropathy (r = 0.366; P < 0.05). CONCLUSIONS The current study has demonstrated an association between markers of sodium channel function and QoL in DN. The study demonstrates that excitability techniques may identify patients in whom altered sodium channel function may be the dominant abnormality. The findings suggest that excitability techniques may have a role in clinical decision making regarding neuropathic treatment prescription.
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Affiliation(s)
- Natalie C G Kwai
- School of Medical Sciences, University of New South Wales, Kensington, Australia
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Silva M, Amorim D, Almeida A, Tavares I, Pinto-Ribeiro F, Morgado C. Pronociceptive changes in the activity of rostroventromedial medulla (RVM) pain modulatory cells in the streptozotocin-diabetic rat. Brain Res Bull 2013; 96:39-44. [PMID: 23644033 DOI: 10.1016/j.brainresbull.2013.04.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 04/06/2013] [Accepted: 04/19/2013] [Indexed: 12/12/2022]
Abstract
Neuropathic pain is one of the most frequent complications of diabetes. The increased neuronal activity of primary afferents and spinal cord neurons in streptozotocin (STZ)-diabetic rats increases the recruitment of the nociceptive ascending pathways, which may affect the activity of pain control circuits in the brain. This study aimed to characterize the electrophysiological responses of neurons of the rostroventromedial medulla (RVM), a key brainstem area involved in descending modulation of nociceptive neurotransmission at the spinal cord, in STZ-diabetic rats. Spontaneous and noxious-evoked activity of ON-like cells (pain facilitatory cells) and OFF-like cells (pain inhibitory cells) in the RVM were analyzed by single cell extracellular electrophysiological recordings in STZ-diabetic rats with behavioral signs of diabetic neuropathic pain 4 weeks after diabetes induction and in age-matched non-diabetic controls (CTRL). The electrophysiological analysis revealed an increase in the spontaneous activity of RVM pronociceptive ON-like cells in STZ-diabetic rats when compared to CTRL. On the contrary, the number of active antinociceptive OFF-like cells was significantly lower in the STZ-diabetic rats and their spontaneous activity was decreased when compared with CTRL. Overall, the changes in the activity of RVM pain modulatory cells in STZ-diabetic rats point to enhancement of descending pain facilitation. Based on similar results obtained at the RVM in traumatic neuropathic pain models, the changes in the electrophysiological responses of RVM in STZ-diabetic rats may account for exacerbated pain-like behaviors in diabetic neuropathy.
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Affiliation(s)
- M Silva
- Department of Experimental Biology, Faculty of Medicine of Porto and IBMC, University of Porto, Rua Dr Plácido Costa, 4200-450 Porto, Portugal.
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Long-term changes in trigeminal ganglionic and thalamic neuronal activities following inferior alveolar nerve transection in behaving rats. J Neurosci 2013; 32:16051-63. [PMID: 23136441 DOI: 10.1523/jneurosci.1828-12.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The transection of the inferior alveolar nerve (IANx) produces allodynia in the whisker pad (V2 division) of rats. Ectopic discharges from injured trigeminal ganglion (TG) neurons and thalamocortical reorganization are possible contributors to the sensitization of uninjured V2 primary and CNS neurons. To test which factor is more important, TG and ventroposterior medial nucleus (VPM) neurons were longitudinally followed before, during, and after IANx for up to 80 d. Spontaneous discharges and mechanical stimulation-evoked responses were recorded in conscious and in anesthetized states. Results show (1) a sequential increase in spontaneous activities, first in the injured TG neurons of the IAN (2-30 d), followed by uninjured V2 ganglion neurons (6-30 d), and then VPM V2 neurons (7-30 d) after IANx; (2) ectopic discharges included burst and regular firing patterns in the IAN and V2 branches of the TG neurons; and (3) the receptive field expanded, the modality shifted, and long-lasting after-discharges occurred only in VPM V2 neurons. All of these changes appeared in the late or maintenance phase (7-30 d) and disappeared during the recovery phase (40-60 d). These observations suggest that ectopic barrages in the injured IAN contribute more to the development of sensitization, whereas the modality shift and evoked after-discharges in the VPM thalamic neurons contribute more to the maintenance phase of allodynia by redirecting tactile information to the cortex as nociceptive.
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Abstract
Diabetic neuropathic pain imposes a huge burden on individuals and society, and represents a major public health problem. Despite aggressive efforts, diabetic neuropathic pain is generally refractory to available clinical treatments. A structure-function link between maladaptive dendritic spine plasticity and pain has been demonstrated previously in CNS and PNS injury models of neuropathic pain. Here, we reasoned that if dendritic spine remodeling contributes to diabetic neuropathic pain, then (1) the presence of malformed spines should coincide with the development of pain, and (2) disrupting maladaptive spine structure should reduce chronic pain. To determine whether dendritic spine remodeling contributes to neuropathic pain in streptozotocin (STZ)-induced diabetic rats, we analyzed dendritic spine morphology and electrophysiological and behavioral signs of neuropathic pain. Our results show changes in dendritic spine shape, distribution, and shape on wide-dynamic-range (WDR) neurons within lamina IV-V of the dorsal horn in diabetes. These diabetes-induced changes were accompanied by WDR neuron hyperexcitability and decreased pain thresholds at 4 weeks. Treatment with NSC23766 (N(6)-[2-[[4-(diethylamino)-1-methylbutyl]amino]-6-methyl-4-pyrimidinyl]-2-methyl-4,6-quinolinediamine trihydrochloride), a Rac1-specific inhibitor known to interfere with spine plasticity, decreased the presence of malformed spines in diabetes, attenuated neuronal hyperresponsiveness to peripheral stimuli, reduced spontaneous firing activity from WDR neurons, and improved nociceptive mechanical pain thresholds. At 1 week after STZ injection, animals with hyperglycemia with no evidence of pain had few or no changes in spine morphology. These results demonstrate that diabetes-induced maladaptive dendritic spine remodeling has a mechanistic role in neuropathic pain. Molecular pathways that control spine morphogenesis and plasticity may be promising future targets for treatment.
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Eaton MJ, Berrocal Y, Wolfe SQ, Widerström-Noga E. Review of the history and current status of cell-transplant approaches for the management of neuropathic pain. PAIN RESEARCH AND TREATMENT 2012; 2012:263972. [PMID: 22745903 PMCID: PMC3382629 DOI: 10.1155/2012/263972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 04/09/2012] [Indexed: 11/18/2022]
Abstract
Treatment of sensory neuropathies, whether inherited or caused by trauma, the progress of diabetes, or other disease states, are among the most difficult problems in modern clinical practice. Cell therapy to release antinociceptive agents near the injured spinal cord would be the logical next step in the development of treatment modalities. But few clinical trials, especially for chronic pain, have tested the transplant of cells or a cell line to treat human disease. The history of the research and development of useful cell-transplant-based approaches offers an understanding of the advantages and problems associated with these technologies, but as an adjuvant or replacement for current pharmacological treatments, cell therapy is a likely near future clinical tool for improved health care.
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Affiliation(s)
- Mary J. Eaton
- Miami VA Health System Center, D806C, 1201 NW 16th Street, Miami, FL 33125, USA
| | - Yerko Berrocal
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
| | - Stacey Q. Wolfe
- Department of Neurosurgery, Tripler Army Medical Center, 1 Jarrett White Road, Honolulu, HI 96859, USA
| | - Eva Widerström-Noga
- Miami VA Health System Center, D806C, 1201 NW 16th Street, Miami, FL 33125, USA
- The Miami Project to Cure Paralysis, Miller School of Medicine at the University of Miami, Miami, FL 33136, USA
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VPL-DBS on neuropathic pain rat model is effective in mechanical allodynia than cold allodynia. Neurol Sci 2012; 33:1265-70. [PMID: 22562402 DOI: 10.1007/s10072-012-1097-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 04/12/2012] [Indexed: 10/28/2022]
Abstract
Recently, deep brain stimulation (DBS) is widely used in various types of neurodegenerative disorders for minimal invasiveness and safety of the procedure. Deep brain stimulation is consistently applied for the treatment of patients with neuropathic pain even though the success rate is not as high as other neurodegenerative disorders. Furthermore, it is also unclear how DBS improves neuropathic pain. In this study, we investigated the role of DBS following the stimulation parameter for analgesic effect on mechanical allodynia and cold allodynia in neuropathic pain rats. We used a sciatic nerve injury model to induce neuropathic pain, and observed responses to mechanical and cold stimulation by the von Frey test and acetone test, respectively. We classified the rats into four groups: naïve (naïve, n = 10), naïve + DBS (N + DBS, n = 10), neuropathic pain (NP, n = 10), and neuropathic pain + DBS (NP + DBS, n = 10). We inserted the DBS electrode into the ventral posterolateral nucleus (VPL) into the rats (VPL-DBS). The score for mechanical allodynia was significantly decreased in NP + DBS group (p < 0.01). However, the score for cold allodynia did not significantly drop in any groups including NP + DBS group (p > 0.05). In this study, we found that the electrical stimulation of the VPL works more effectively with mechanical allodynia than cold one, and pain signal induced by mechanical stimulus and cold stimulus may be processed through different pathways in the brain.
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Petrou M, Pop-Busui R, Foerster BR, Edden RA, Callaghan BC, Harte SE, Harris RE, Clauw DJ, Feldman EL. Altered excitation-inhibition balance in the brain of patients with diabetic neuropathy. Acad Radiol 2012; 19:607-12. [PMID: 22463961 DOI: 10.1016/j.acra.2012.02.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 02/22/2012] [Accepted: 02/23/2012] [Indexed: 12/13/2022]
Abstract
RATIONALE AND OBJECTIVES To assess differences in excitatory (glutamate/glutamine or Glx) and inhibitory (γ-Aminobutyric acid or GABA) neurotransmitter levels using MR spectroscopy in pain processing regions of the brain in patients diabetic neuropathy (DN) and positive sensory symptoms and age-matched healthy control (HC) subjects. MATERIALS AND METHODS Seven diabetic patients (5 males, 2 females, mean age = 57.0 ± 8.5 years) with confirmed DN and positive sensory symptoms and 7 age and sex matched HC subjects (mean age = 57.7 ± 3.2 years) underwent 3 Tesla MR spectroscopy. Glx and GABA levels were quantified in the right anterior and posterior insula, anterior cingulate cortex and right thalamus. RESULTS Mean Glx levels were significantly higher and mean GABA levels were significantly lower within the posterior insula in the DN patients compared to HC (P = 0.005 and 0.012 respectively). CONCLUSIONS This pilot data demonstrates an excitatory/inhibitory neurotransmitter imbalance in the brain of in patients with DN and positive sensory symptoms compared to pain free HC subjects.
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Affiliation(s)
- Myria Petrou
- Department of Radiology, Division of Neuroradiology, University of Michigan, 1500 E. Medical Center Drive, SPC 5030, UH B2 A209, Ann Arbor, MI 48109-5030, USA.
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Waxman SG. Sodium channels, the electrogenisome and the electrogenistat: lessons and questions from the clinic. J Physiol 2012; 590:2601-12. [PMID: 22411010 DOI: 10.1113/jphysiol.2012.228460] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In the six decades that have followed the work of Hodgkin and Huxley, multiple generations of neuroscientists and biophysicists have built upon their pivotal contributions. It is now clear that, in mammals, nine genes encode nine distinct voltage-gated sodium channels with different amino acid sequences and different physiological and pharmacological properties. The different sodium channel isoforms produce a multiplicity of distinct sodium currents with different time-dependent characteristics and voltage dependencies, which interact with each other and with the currents produced by other channels (including calcium and potassium channels) to shape neuronal firing patterns. Expression of these sodium channel isoforms is highly dynamic, both in the normal nervous system, and in the injured nervous system. Recent research has shed light on the roles of sodium channels in human disease, a development that may open up new therapeutic strategies. This article examines the pain-signalling system as an example of a neuronal network where multiple sodium channel isoforms play complementary roles in electrogenesis and a strong link with human disease has been established. Recent research suggests that it may be possible to target specific sodium channel isoforms that drive hyperexcitability in pain-signalling neurons, thereby providing new therapeutic strategies for chronic pain, and providing an illustration of the impact of the Hodgkin-Huxley legacy in the clinical domain.
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Affiliation(s)
- Stephen G Waxman
- Department of Neurology and Centre for Neuroscience & Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA.
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Tesfaye S, Selvarajah D. Advances in the epidemiology, pathogenesis and management of diabetic peripheral neuropathy. Diabetes Metab Res Rev 2012; 28 Suppl 1:8-14. [PMID: 22271716 DOI: 10.1002/dmrr.2239] [Citation(s) in RCA: 347] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Diabetic peripheral neuropathy (DPN) affects up to 50% of patients with diabetes and is a major cause of morbidity and increased mortality. Its clinical manifestations include painful neuropathic symptoms and insensitivity, which increases the risk for burns, injuries and foot ulceration. Several recent studies have implicated poor glycaemic control, duration of diabetes, hyperlipidaemia (particularly hypertryglyceridaemia), elevated albumin excretion rates and obesity as risk factors for the development of DPN. Although there is now strong evidence for the importance of nerve microvascular disease in the pathogenesis of DPN, the risk factors for painful DPN are not known. However, emerging evidence regarding the central correlates of painful DPN is now afforded by brain imaging. The diagnosis of DPN begins with a careful history of sensory and motor symptoms. The quality and severity of neuropathic pain if present should be assessed using a suitable scale. Clinical examination should include inspection of the feet and evaluation of reflexes and sensory responses to vibration, light touch, pinprick and the 10-g monofilament. Glycaemic control and addressing cardiovascular risk is now considered important in the overall management of the neuropathic patient. Pharmacological treatment of painful DPN includes tricyclic compounds, serotonin-norepinephrine reuptake inhibitors (e.g. duloxetine), anticonvulsants (e.g. pregabalin), opiates, membrane stabilizers, the antioxidant alpha lipoic acid and others. Over the past 7 years, new agents with perhaps less side effect profiles have immerged. Management of patients with painful neuropathy must be tailored to individual requirements and will depend on the presence of other co-morbidities. There is limited literature with regard to combination treatment.
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