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Dhanapalaratnam R, Issar T, Poynten AM, Milner KL, Kwai NCG, Krishnan AV. Progression of axonal excitability abnormalities with increasing clinical severity of diabetic peripheral neuropathy. Clin Neurophysiol 2024; 160:12-18. [PMID: 38367309 DOI: 10.1016/j.clinph.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 01/18/2024] [Accepted: 02/05/2024] [Indexed: 02/19/2024]
Abstract
OBJECTIVE Diabetic peripheral neuropathy (DPN) is a frequent complication for persons with type 2 diabetes. Previous studies have failed to demonstrate any significant impact of treatment for DPN. The present study assessed the role of axonal ion channel dysfunction in DPN and explored the hypothesis that there may be a progressive change in ion channel abnormalities that varied with disease stage. METHODS Neurophysiological studies were conducted using axonal excitability techniques, a clinical method of assessing ion channel dysfunction. Studies were conducted in 178 persons with type 2 diabetes, with participants allocated into four groups according to clinical severity of neuropathy, assessed using the Total Neuropathy Grade. RESULTS Analysis of excitability data demonstrated a progressive and stepwise reduction in two parameters that are related to the activity of Kv1.1 channels, namely superexcitability and depolarizing threshold electrotonus at 10-20 ms (p < 0.001), and mathematical modelling of axonal excitability findings supported progressive upregulation of Kv1.1 conductances with increasing greater disease severity. CONCLUSION The findings are consistent with a progressive upregulation of juxtaparanodal Kv1.1 conductances with increasing clinical severity of diabetic peripheral neuropathy. SIGNIFICANCE From a translational perspective, the study suggests that blockade of Kv1.1 channels using 4-aminopyridine derivatives such as fampridine may be a potential treatment for DPN.
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Affiliation(s)
- Roshan Dhanapalaratnam
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia; Department of Neurology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
| | - Tushar Issar
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia
| | - Ann M Poynten
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia; Department of Endocrinology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
| | - Kerry-Lee Milner
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia; Department of Endocrinology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
| | - Natalie C G Kwai
- School of Medical, Indigenous and Health Sciences, University of Wollongong, Australia
| | - Arun V Krishnan
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia; Department of Neurology, Prince of Wales Hospital, Sydney, NSW 2031, Australia.
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Carroll AS, Park SB, Lin CSY, Taylor MS, Kwok F, Simon NG, Reilly MM, Kiernan MC, Vucic S. Axonal excitability as an early biomarker of nerve involvement in hereditary transthyretin amyloidosis. Clin Neurophysiol 2024; 159:81-95. [PMID: 38377648 DOI: 10.1016/j.clinph.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/26/2023] [Accepted: 01/22/2024] [Indexed: 02/22/2024]
Abstract
OBJECTIVES The treatment of hereditary transthyretin amyloidosis polyneuropathy (ATTRv-PN) has been revolutionised by genetic therapies, with dramatic improvements in patient outcomes. Whilst the optimal timing of treatment initiation remains unknown, early treatment is desirable. Consequently, the aim of the study was to develop biomarkers of early nerve dysfunction in ATTRv-PN. METHODS Ulnar motor and sensory axonal excitability studies were prospectively undertaken on 22 patients with pathogenic hereditary transthyretin amyloid (ATTRv) gene variants, 12 with large fibre neuropathy (LF+) and 10 without (LF-), with results compared to age- and sex-matched healthy controls. RESULTS In motor axons we identified a continuum of change from healthy controls, to LF- and LF+ ATTRv with progressive reduction in hyperpolarising threshold electrotonus (TEh40(10-20 ms): p = 0.04, TEh40(20-40 ms): p = 0.01 and TEh40(90-10 ms): p = 0.01), suggestive of membrane depolarisation. In sensory axons lower levels of subexcitability were observed on single (SubEx) and double pulse (SubEx2) recovery cycle testing in LF+ (SubEx: p = 0.015, SubEx2: p = 0.015, RC(2-1): p = 0.04) suggesting reduced nodal slow potassium conductance, which promotes sensory hyperexcitability, paraesthesia and pain. There were no differences in sensory or motor excitability parameters when comparing different ATTRv variants. CONCLUSIONS These progressive changes seen across the disease spectrum in ATTRv-PN suggest that axonal excitability has utility to identify early and progressive nerve dysfunction in ATTRv, regardless of genotype. SIGNIFICANCE Axonal excitability is a promising early biomarker of nerve dysfunction in ATTRv-PN.
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Affiliation(s)
- Antonia S Carroll
- Brain and Mind Centre, Faculty of Medicine and Health, Translational Research Collective University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Sydney, Australia; Westmead Amyloidosis Centre, Westmead Hospital, University of Sydney, Sydney, Australia; Centre for Neuromuscular Disease, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK.
| | - Susanna B Park
- Brain and Mind Centre, Faculty of Medicine and Health, School of Medical Sciences, University of Sydney, Sydney, Australia
| | - Cindy S Y Lin
- Brain and Mind Centre, Faculty of Medicine and Health, Translational Research Collective University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Sydney, Australia
| | - Mark S Taylor
- Westmead Amyloidosis Centre, Westmead Hospital, University of Sydney, Sydney, Australia
| | - Fiona Kwok
- Westmead Amyloidosis Centre, Westmead Hospital, University of Sydney, Sydney, Australia
| | - Neil G Simon
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Mary M Reilly
- Centre for Neuromuscular Disease, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Matthew C Kiernan
- Brain and Mind Centre, Faculty of Medicine and Health, Translational Research Collective University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Sydney, Australia
| | - Steve Vucic
- Brain and Nerve Centre, Concord Hospital, University of Sydney, Sydney, Australia
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Maxion A, Kutafina E, Dohrn MF, Sacré P, Lampert A, Tigerholm J, Namer B. A modelling study to dissect the potential role of voltage-gated ion channels in activity-dependent conduction velocity changes as identified in small fiber neuropathy patients. Front Comput Neurosci 2023; 17:1265958. [PMID: 38156040 PMCID: PMC10752960 DOI: 10.3389/fncom.2023.1265958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 10/25/2023] [Indexed: 12/30/2023] Open
Abstract
Objective Patients with small fiber neuropathy (SFN) suffer from neuropathic pain, which is still a therapeutic problem. Changed activation patterns of mechano-insensitive peripheral nerve fibers (CMi) could cause neuropathic pain. However, there is sparse knowledge about mechanisms leading to CMi dysfunction since it is difficult to dissect specific molecular mechanisms in humans. We used an in-silico model to elucidate molecular causes of CMi dysfunction as observed in single nerve fiber recordings (microneurography) of SFN patients. Approach We analyzed microneurography data from 97 CMi-fibers from healthy individuals and 34 of SFN patients to identify activity-dependent changes in conduction velocity. Using the NEURON environment, we adapted a biophysical realistic preexisting CMi-fiber model with ion channels described by Hodgkin-Huxley dynamics for identifying molecular mechanisms leading to those changes. Via a grid search optimization, we assessed the interplay between different ion channels, Na-K-pump, and resting membrane potential. Main results Changing a single ion channel conductance, Na-K-pump or membrane potential individually is not sufficient to reproduce in-silico CMi-fiber dysfunction of unchanged activity-dependent conduction velocity slowing and quicker normalization of conduction velocity after stimulation as observed in microneurography. We identified the best combination of mechanisms: increased conductance of potassium delayed-rectifier and decreased conductance of Na-K-pump and depolarized membrane potential. When the membrane potential is unchanged, opposite changes in Na-K-pump and ion channels generate the same effect. Significance Our study suggests that not one single mechanism accounts for pain-relevant changes in CMi-fibers, but a combination of mechanisms. A depolarized membrane potential, as previously observed in patients with neuropathic pain, leads to changes in the contribution of ion channels and the Na-K-pump. Thus, when searching for targets for the treatment of neuropathic pain, combinations of several molecules in interplay with the membrane potential should be regarded.
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Affiliation(s)
- Anna Maxion
- Research Group Neuroscience, Interdisciplinary Centre for Clinical Research within the Faculty of Medicine at the RWTH Aachen University, Aachen, Germany
| | - Ekaterina Kutafina
- Institute of Medical Informatics, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Maike F. Dohrn
- Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Pierre Sacré
- Department of Electrical Engineering and Computer Science, University of Liège, Liège, Belgium
| | - Angelika Lampert
- Institute of Neurophysiology, Uniklinik RWTH Aachen University Aachen, Aachen, Germany
| | - Jenny Tigerholm
- Joint Research Center for Computational Biomedicine, RWTH Aachen, Aachen, Germany
| | - Barbara Namer
- Research Group Neuroscience, Interdisciplinary Centre for Clinical Research within the Faculty of Medicine at the RWTH Aachen University, Aachen, Germany
- Institute of Neurophysiology, RWTH Aachen University, Aachen, Germany
- Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, Erlangen, Germany
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Thouaye M, Yalcin I. Neuropathic pain: From actual pharmacological treatments to new therapeutic horizons. Pharmacol Ther 2023; 251:108546. [PMID: 37832728 DOI: 10.1016/j.pharmthera.2023.108546] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 09/07/2023] [Accepted: 10/05/2023] [Indexed: 10/15/2023]
Abstract
Neuropathic pain, caused by a lesion or disease affecting the somatosensory system, affects between 3 and 17% of the general population. The treatment of neuropathic pain is challenging due to its heterogeneous etiologies, lack of objective diagnostic tools and resistance to classical analgesic drugs. First-line treatments recommended by the Special Interest Group on Neuropathic Pain (NeuPSIG) and European Federation of Neurological Societies (EFNS) include gabapentinoids, tricyclic antidepressants (TCAs) and selective serotonin noradrenaline reuptake inhibitors (SNRIs). Nevertheless these treatments have modest efficacy or dose limiting side effects. There is therefore a growing number of preclinical and clinical studies aim at developing new treatment strategies to treat neuropathic pain with better efficacy, selectivity, and less side effects. In this review, after a brief description of the mechanisms of action, efficacy, and limitations of current therapeutic drugs, we reviewed new preclinical and clinical targets currently under investigation, as well as promising non-pharmacological alternatives and their potential co-use with pharmacological treatments.
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Affiliation(s)
- Maxime Thouaye
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Ipek Yalcin
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France; Department of Psychiatry and Neuroscience, Université Laval, Québec, QC G1V 0A6, Canada.
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Sonawane K, Dixit H, Thota N, Mistry T, Balavenkatasubramanian J. "Knowing It Before Blocking It," the ABCD of the Peripheral Nerves: Part B (Nerve Injury Types, Mechanisms, and Pathogenesis). Cureus 2023; 15:e43143. [PMID: 37692583 PMCID: PMC10484240 DOI: 10.7759/cureus.43143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2023] [Indexed: 09/12/2023] Open
Abstract
Selander emphatically said, "Handle these nerves with care," and those words still echo, conveying a loud and clear message that, however rare, peripheral nerve injury (PNI) remains a perturbing possibility that cannot be ignored. The unprecedented nerve injuries associated with peripheral nerve blocks (PNBs) can be most tormenting for the unfortunate patient and a nightmare for the anesthetist. Possible justifications for the seemingly infrequent occurrences of PNB-related PNIs include a lack of documentation/reporting, improper aftercare, or associated legal implications. Although they make up only a small portion of medicolegal claims, they are sometimes difficult to defend. The most common allegations are attributed to insufficient informed consent; preventable damage to a nerve(s); delay in diagnosis, referral, or treatment; misdiagnosis, and inappropriate treatment and follow-up care. Also, sufficient prospective studies or randomized trials have not been conducted, as exploring such nerve injuries (PNB-related) in living patients or volunteers may be impractical or unethical. Understanding the pathophysiology of various types of nerve injury is vital to dealing with them further. Processes like degeneration, regeneration, remyelination, and reinnervation can influence the findings of electrophysiological studies. Events occurring in such a process and their impact during the assessment determine the prognosis and the need for further interventions. This educational review describes various types of PNB-related nerve injuries and their associated pathophysiology.
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Affiliation(s)
- Kartik Sonawane
- Anesthesiology, Ganga Medical Centre and Hospitals, Coimbatore, IND
| | - Hrudini Dixit
- Anesthesiology, Sir H. N. Reliance Foundation Hospital and Research Centre, Mumbai, IND
| | - Navya Thota
- Anesthesiology, Ganga Medical Centre and Hospitals, Coimbatore, IND
| | - Tuhin Mistry
- Anesthesiology, Ganga Medical Centre and Hospitals, Coimbatore, IND
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Nakazato T, Kanai K, Kataura T, Nojiri S, Hattori N, Saiki S. Plasma taurine is an axonal excitability-translatable biomarker for amyotrophic lateral sclerosis. Sci Rep 2022; 12:9155. [PMID: 35650294 PMCID: PMC9160240 DOI: 10.1038/s41598-022-13397-6] [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: 11/10/2021] [Accepted: 05/24/2022] [Indexed: 12/12/2022] Open
Abstract
Although various body fluid biomarkers for amyotrophic lateral sclerosis (ALS) have been reported, no biomarkers specifically reflecting abnormalities in axonal excitability indices have currently been established. Capillary electrophoresis time-of-flight mass spectrometry and liquid chromatography time-of-flight mass spectrometry were used to perform a comprehensive metabolome analysis of plasma from seven ALS patients and 20 controls, and correlation analysis with disease phenotypes was then performed in 22 other ALS patients. Additionally, electrophysiological studies of motor nerve axonal excitability were performed in all ALS patients. In the ALS and control groups, levels of various metabolites directly associated with skeletal muscle metabolism, such as those involved in fatty acid β-oxidation and the creatine pathway, were detected. Receiver operating characteristic curve analysis of the top four metabolites (ribose-5-phosphate, N6-acetyllysine, dyphylline, 3-methoxytyrosine) showed high diagnostic accuracy (area under the curve = 0.971) in the ALS group compared with the control group. Furthermore, hierarchical cluster analysis revealed that taurine levels were correlated with the strength-duration time constant, an axonal excitability indicator established to predict survival. No significant effects of diabetes mellitus and treatment (Riluzole and Edaravone) on this relationship were detected in the study. Therefore, plasma taurine is a potential novel axonal excitability-translatable biomarker for ALS.
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Affiliation(s)
- Tomoko Nakazato
- Department of Neurology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Kazuaki Kanai
- Department of Neurology, Fukushima Medical University, Fukushima, Japan
| | - Tetsushi Kataura
- Department of Neurology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Shuko Nojiri
- Clinical Research Center, Juntendo University, Tokyo, Japan
| | - Nobutaka Hattori
- Department of Neurology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Shinji Saiki
- Department of Neurology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
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Khafagi AT, Yehia MA, Helmy AK, Hassan W, Abdelhakim N. Effect of Erythropoietin-stimulating agent on uremic neuropathy in hemodialysis patients: a single-center open-label prospective study. THE EGYPTIAN JOURNAL OF NEUROLOGY, PSYCHIATRY AND NEUROSURGERY 2022. [DOI: 10.1186/s41983-022-00477-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Uremic neuropathy is a distal sensorimotor polyneuropathy caused by uremic toxins; its severity is correlated with the degree of renal insufficiency. Erythropoietin (EPO) and erythropoietin receptors (EpoR) are produced in the peripheral nervous system. This is a single-center open-label prospective study was designed to investigate the possible effect of erythropoietin-stimulating agents (ESAs) on uremic neuropathy. Twenty-four newly diagnosed end-stage kidney disease (ESKD) patients were selected, clinical assessment, laboratory, and neurophysiological study were done at 1 and follow-up after 3 months. Patients were divided into two groups (group A received ESA and group B did not receive ESA).
Results
Eighteen patients completed the study, eight patients (44.4%) did not have symptoms but had electrophysiological findings of neuropathy (subclinical neuropathy). After 3 months of hemodialysis, patients in group A showed improvement of some electrophysiological features (ulnar MNCV; P = 0.016).
Conclusions
The use of ESA may improve uremic neuropathy in patients with newly diagnosed ESKD who have been started on hemodialysis.
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The additional diagnostic value of motor nerve excitability testing in chronic axonal neuropathy. Clin Neurophysiol Pract 2022; 7:27-33. [PMID: 35128215 PMCID: PMC8803553 DOI: 10.1016/j.cnp.2021.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/23/2021] [Accepted: 12/27/2021] [Indexed: 11/29/2022] Open
Abstract
Nerve excitability testing was correlated with conventional nerve conduction studies. Nerve excitability testing was similar in patients with and without neuropathy and normal nerve conduction. There is no support for the potential additional diagnostic value of nerve excitability testing in mixed etiology neuropathy.
Objective To explore potential differences in motor nerve excitability testing (NET) variables at group levels between patients with a clinical diagnosis of polyneuropathy (PNP), which did not fulfil diagnostic criteria of conventional nerve conduction studies (NCS) and patients without polyneuropathy. Such differences could support a role for NET in increasing the diagnostic sensitivity of NCS in chronic axonal PNP. Methods Motor NET was performed using the median nerve in patients with a clinical suspicion of PNP in addition to conventional NCS, skin biopsies, corneal confocal microscopy and structured clinical evaluation including scoring of neuropathy symptoms and signs. Results Of the 57 patients included, 32 had PNP, half of which had NCS, which fulfilled criteria for PNP (NCS+ PNP). There were no significant differences for any of the NET variables between PNP patients with non-diagnostic conventional NCS (NCS− PNP) and patients without PNP. Rheobase was increased, and Ted (undershoot) and subexcitability were decreased in NCS+ PNP. Sural amplitude, peroneal nerve F-wave latency and tibial nerve F-wave-latency were correlated with subexcitability, and tibial nerve motor amplitude was correlated with rheobase. Conclusions NET was correlated with conventional NCS and no differences were found between NCS− PNP patients and patients without PNP. Significance NET does not seem to offer any additional diagnostic value in chronic mixed etiology neuropathy.
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Carroll AS, Howells J, Lin CS, Park SB, Simon N, Reilly MM, Vucic S, Kiernan MC. Differences in nerve excitability properties across upper limb sensory and motor axons. Clin Neurophysiol 2021; 136:138-149. [DOI: 10.1016/j.clinph.2021.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 11/16/2021] [Accepted: 12/07/2021] [Indexed: 11/24/2022]
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Effect of exenatide on peripheral nerve excitability in type 2 diabetes. Clin Neurophysiol 2021; 132:2532-2539. [PMID: 34455311 DOI: 10.1016/j.clinph.2021.05.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/26/2021] [Accepted: 05/25/2021] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To assess the effect of exenatide (a GLP-1 receptor agonist), dipeptidyl peptidase-IV (DPP-IV) inhibitors, and sodium-glucose co-transporter 2 (SGLT-2) inhibitors on measures of peripheral nerve excitability in patients with type 2 diabetes. METHODS Patients receiving either exenatide (n = 32), a DPP-IV inhibitor (n = 31), or a SGLT-2 inhibitor (n = 27) underwent motor nerve excitability assessments. Groups were similar in age, sex, HbA1c, diabetes duration, lipids, and neuropathy severity. An additional 10 subjects were assessed prospectively over 3 months while oral anti-hyperglycaemic therapy was kept constant. A cohort of healthy controls (n = 32) were recruited for comparison. RESULTS Patients receiving a DPP-IV or SGLT-2 inhibitor demonstrated abnormalities in peak threshold reduction, S2 accommodation, superexcitability, and subexcitability. In contrast, patients treated with exenatide were observed to have normal nerve excitability. In the prospective arm, exenatide therapy was associated with an improvement in nerve function as patients demonstrated corrections in S2 accommodation, superexcitability, and subexcitability at follow-up. These changes were independent of the reductions in HbA1c following exenatide treatment. CONCLUSIONS Exenatide was associated with an improvement in measures of nerve excitability in patients with type 2 diabetes. SIGNIFICANCE Exenatide may improve peripheral nerve function in type 2 diabetes.
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Dohrn MF, Winter N, Dumke C, Bähr F, Ouwenbroek A, Hoppe B, Reiners K, Dafotakis M. Stellenwert klinischer, funktioneller und bildgebender Diagnostik zur Früherkennung, Differenzialdiagnose und Verlaufskontrolle diabetischer Neuropathien. KLIN NEUROPHYSIOL 2021. [DOI: 10.1055/a-1335-1086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
ZusammenfassungVon weltweit mehr als 400 Mio. Menschen mit Diabetes mellitus entwickeln bis zu 50% im Laufe ihrer Erkrankung eine Neuropathie. Trotz oder gerade wegen dieser Häufigkeit darf jedoch nicht jede Neuropathie, die in Koinzidenz mit einem Diabetes mellitus auftritt, unkritisch als diabetische Neuropathie diagnostiziert werden. Eine präzise Ausschluss- und Ausmaßdiagnostik ist entscheidend, um andere behandelbare Erkrankungen wie z. B. die Chronisch Inflammatorische Demyelinisierende Polyradikuloneuropathie oder die hereditäre Transthyretin-Amyloidose nicht zu übersehen. Einfache, nicht-invasive, preiswerte und allzeit verfügbare Screeningmethoden stellen Anamnese und klinische Untersuchung dar. Ergänzend ist in frühen Erkrankungsstadien die Quantitativ Sensorische Testung hilfreich zur Eingrenzung einer Small Fiber-Dysfunktion. Sind, typischerweise im Verlauf, große Nervenfasern geschädigt, so ist das charakteristische elektrophysiologische Bild das einer längenabhängigen, axonalen, sensibel betonten oder sensomotorischen Neuropathie. Die Nervensonografie kann zur Unterscheidung von autoimmun-demyelinisierenden Neuropathien hilfreich sein. Moderne Untersuchungsverfahren wie die MR-Neurografie können auch proximale Nervenabschnitte bis auf Faszikelebene darstellen, sind allerdings nur an wenigen Zentren verfügbar. Haut- und Nervenbiopsien sind v. a. bei untypischen Verläufen zur Abgrenzung von Differenzialdiagnosen hilfreich. Diabetische Neuropathien können zu einer erheblichen Reduktion von Lebensqualität und Lebensdauer führen. Zur frühest- und bestmöglichen ursächlichen und symptomatischen Therapieeinleitung ist eine präzise Diagnostik essentiell.
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Affiliation(s)
- Maike F. Dohrn
- Neurologie, Uniklinik der RWTH Aachen, Aachen, Deutschland
| | - Natalie Winter
- Neurologie, Universitätsklinikum Tübingen, Tübingen, Deutschland
| | | | | | | | - Barbara Hoppe
- Neurologie, Klinikum Köln-Merheim, Köln, Deutschland
| | - Karlheinz Reiners
- Neurologie, Hermann-Josef-Krankenhaus Erkelenz, Erkelenz, Deutschland
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Kristensen AG, Gylfadottir S, Itani M, Kuwabara S, Krøigård T, Khan KS, Finnerup NB, Andersen H, Jensen TS, Sindrup S, Tankisi H. Sensory and motor axonal excitability testing in early diabetic neuropathy. Clin Neurophysiol 2021; 132:1407-1415. [PMID: 34030050 DOI: 10.1016/j.clinph.2021.02.397] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 01/30/2021] [Accepted: 02/01/2021] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The aim of the present study was to gain insight into the pathophysiology of diabetic polyneuropathy (DPN) and examine the diagnostic value of sensory and motor axonal excitability testing. METHODS One hundred and eleven type 2 diabetics with and without DPN (disease duration: 6.36 ± 0.25 years) and 60 controls were included. All participants received a thorough clinical examination including Michigan Neuropathy Screening Instrument (MNSI) score, nerve conduction studies (NCS), and sensory and motor excitability tests. Patients were compared by the likelihood of neuropathy presence, ranging from no DPN (17), possible/probable DPN (46) to NCS-confirmed DPN (48). RESULTS Motor excitability tests showed differences in rheobase and depolarizing threshold electrotonus measures between NCS-confirmed DPN group and controls but no changes in hyperpolarising threshold electrotonus or recovery cycle parameters. Sensory excitability showed even less changes despite pronounced sensory NCS abnormalities. There were only weak correlations between the above motor excitability parameters and clinical scores. CONCLUSIONS Changes in excitability in the examined patient group were subtle, perhaps because of the relatively short disease duration. SIGNIFICANCE Less pronounced excitability changes than NCS suggest that axonal excitability testing is not of diagnostic value for early DPN and does not provide information on the mechanisms.
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Affiliation(s)
- A G Kristensen
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark; Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Denmark
| | - S Gylfadottir
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Denmark; Department of Neurology, Aarhus University Hospital, Denmark
| | - M Itani
- Department of Neurology, Odense University Hospital, Denmark
| | - S Kuwabara
- Department of Neurology, Graduate School of Medicine, Chiba University, Japan
| | - T Krøigård
- Department of Neurology, Odense University Hospital, Denmark
| | - K S Khan
- Department of Neurology, Aarhus University Hospital, Denmark
| | - N B Finnerup
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Denmark; Department of Neurology, Aarhus University Hospital, Denmark
| | - H Andersen
- Department of Neurology, Aarhus University Hospital, Denmark
| | - T S Jensen
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Denmark; Department of Neurology, Aarhus University Hospital, Denmark
| | - S Sindrup
- Department of Neurology, Odense University Hospital, Denmark
| | - H Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark.
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Issar T, Yan A, Kwai NCG, Poynten AM, Borire AA, Arnold R, Krishnan AV. Altered peripheral nerve structure and function in latent autoimmune diabetes in adults. Diabetes Metab Res Rev 2020; 36:e3260. [PMID: 31833206 DOI: 10.1002/dmrr.3260] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 11/14/2019] [Accepted: 11/27/2019] [Indexed: 11/07/2022]
Abstract
AIM The present study was undertaken to investigate mechanisms of peripheral nerve dysfunction in latent autoimmune diabetes in adults (LADA). MATERIALS AND METHODS Participants with LADA (n = 15) underwent median nerve ultrasonography and nerve excitability to examine axonal structure and function, in comparison to cohorts of type 1 diabetes (n = 15), type 2 diabetes (n = 23) and healthy controls (n = 26). The LADA group was matched for diabetes duration, glycaemic control, and neuropathy severity with the type 1 and type 2 diabetes groups. A validated mathematical model of the human axon was utilized to investigate the pathophysiological basis of nerve dysfunction. RESULTS The most severe changes in nerve structure and function were noted in the LADA group. The LADA cohort demonstrated a significant increase in nerve cross-sectional area compared to type 1 participants and controls. Compared to type 1 and 2 diabetes, measures of threshold electrotonus, which assesses nodal and internodal conductances, were significantly worse in LADA in response to both depolarising currents and hyperpolarising currents. In the recovery cycle, participants with LADA had a significant increase in the relative refractory period. Mathematical modelling of excitability recordings indicated the basis of nerve dysfunction in LADA was different to type 1 and 2 diabetes. CONCLUSIONS Participants with LADA exhibited more severe changes in nerve function and different underlying pathophysiological mechanisms compared to participants with type 1 or 2 diabetes. Intensive management of risk factors to delay the progression of neuropathy in LADA may be required.
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Affiliation(s)
- Tushar Issar
- Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
| | - Aimy Yan
- Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
| | - Natalie C G Kwai
- Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- Department of Exercise Physiology, UNSW Sydney, Sydney, New South Wales, Australia
| | - Ann M Poynten
- Department of Endocrinology, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Adeniyi A Borire
- Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
| | - Ria Arnold
- Department of Exercise Physiology, UNSW Sydney, Sydney, New South Wales, Australia
| | - Arun V Krishnan
- Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
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Lin Y, Lin CS, Chang T, Lee J, Tani J, Chen H, Sung J. Early sensory neurophysiological changes in prediabetes. J Diabetes Investig 2020; 11:458-465. [PMID: 31563156 PMCID: PMC7078118 DOI: 10.1111/jdi.13151] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/19/2019] [Accepted: 09/25/2019] [Indexed: 12/14/2022] Open
Abstract
AIMS/INTRODUCTION To elucidate whether axonal changes arise in the prediabetic state and to find a biomarker for early detection of neurophysiological changes. MATERIALS AND METHODS We enrolled asymptomatic diabetes patients, as well as prediabetic and normoglycemic individuals to test sensory nerve excitability, and we analyzed those findings and their correlation with clinical profiles. RESULTS In nerve excitability tests, superexcitability in the recovery cycle showed increasing changes in the normoglycemic, prediabetes and diabetes cohorts (-19.09 ± 4.56% in normoglycemia, -22.39 ± 3.16% in prediabetes and -23.71 ± 5.15% in diabetes, P = 0.002). Relatively prolonged distal sensory latency was observed in the median nerve (3.12 ± 0.29 ms in normoglycemia, 3.23 ± 0.38 ms in prediabetes and 3.45 ± 0.43 ms in diabetes, P = 0.019). Superexcitability was positively correlated with fasting plasma glucose (r = 0.291, P = 0.009) and glycated hemoglobin (r = 0.331, P = 0.003) in all participants. CONCLUSIONS Sensory superexcitability and latencies are the most sensitive parameters for detecting preclinical physiological dysfunction in prediabetes. In addition, changes in favor of superexcitability were positively correlated with glycated hemoglobin for all participants. These results suggest that early axonal changes start in the prediabetic stage, and that the monitoring strategy for polyneuropathy should start as early as prediabetes.
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Affiliation(s)
- Yi‐Chen Lin
- Department of NeurologyTaipei Municipal Wanfang HospitalTaipei Medical UniversityTaipeiTaiwan
- Neuroscience InstituteTaipei Medical UniversityTaipeiTaiwan
| | - Cindy Shin‐Yi Lin
- Neural Regenerative MedicineCollege of Medical Science and TechnologyTaipei Medical University and National Health Research InstitutesTaipeiTaiwan
- The Kam Ling Barbara Lo Chair in Neurodegenerative DisordersCentral Clinical SchoolFaculty of Medicine and Health, Brain and Mind CenterThe University of SydneySydneyAustralia
| | - Tsui‐San Chang
- Department of NeurologyTaipei Municipal Wanfang HospitalTaipei Medical UniversityTaipeiTaiwan
- Neuroscience InstituteTaipei Medical UniversityTaipeiTaiwan
- Department of NeurologySchool of Medicine, College of MedicineTaipei Medical UniversityTaipeiTaiwan
| | - Jing‐Er Lee
- Department of NeurologyTaipei Municipal Wanfang HospitalTaipei Medical UniversityTaipeiTaiwan
- Neuroscience InstituteTaipei Medical UniversityTaipeiTaiwan
| | - Jowy Tani
- Department of NeurologyTaipei Municipal Wanfang HospitalTaipei Medical UniversityTaipeiTaiwan
- Neuroscience InstituteTaipei Medical UniversityTaipeiTaiwan
- Neural Regenerative MedicineCollege of Medical Science and TechnologyTaipei Medical University and National Health Research InstitutesTaipeiTaiwan
- Ph.D. Program for Neural Regenerative MedicineCollege of Medical Science and TechnologyTaipei Medical University and National Health Research InstitutesTaipeiTaiwan
| | - Hung‐Ju Chen
- Department of NeurologyTaipei Municipal Wanfang HospitalTaipei Medical UniversityTaipeiTaiwan
- Neuroscience InstituteTaipei Medical UniversityTaipeiTaiwan
| | - Jia‐Ying Sung
- Department of NeurologyTaipei Municipal Wanfang HospitalTaipei Medical UniversityTaipeiTaiwan
- Neuroscience InstituteTaipei Medical UniversityTaipeiTaiwan
- Department of NeurologySchool of Medicine, College of MedicineTaipei Medical UniversityTaipeiTaiwan
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Tummanapalli SS, Issar T, Kwai N, Poynten A, Krishnan AV, Willcox M, Markoulli M. Association of corneal nerve loss with markers of axonal ion channel dysfunction in type 1 diabetes. Clin Neurophysiol 2020; 131:145-154. [DOI: 10.1016/j.clinph.2019.09.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/29/2019] [Accepted: 09/29/2019] [Indexed: 01/06/2023]
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Zhang GY, Chen YF, Dai WX, Zhang D, Huang Y, He WZ, Lin CX. Diabetic Peripheral Neuropathy Increases Electrical Stimulation Threshold of Sciatic Nerve: A Prospective Parallel Cohort Study. Diabetes Metab Syndr Obes 2020; 13:4447-4455. [PMID: 33239897 PMCID: PMC7680690 DOI: 10.2147/dmso.s277473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 11/03/2020] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To investigate the impact of diabetic peripheral neuropathy and its severity on the threshold of sciatic nerve electrical stimulation in diabetic patients. PATIENTS AND METHODS The case-control study included 60 patients that were divided into non-diabetic patients (control group, n = 26) and diabetic patients (diabetes group, n = 34). All the patients who were scheduled for lower leg, foot, and ankle surgery received a popliteal sciatic nerve block. We recorded the minimum current required to produce motor activity of the sciatic nerve during ultrasound-guided popliteal sciatic nerve block. RESULTS Among the 60 patients, the sciatic nerve innervated muscle contractile response was successfully elicited in 57 patients (dorsiflexion of foot, plantar flexion, foot valgus or adduction, toe flexion, etc.) under electric stimulation. We failed to elicit the motor response in three patients with diabetic peripheral neuropathy, even when the stimulation current was 3 mA. The average electrical stimulation threshold (1.0 ± 0.7 mA) in the diabetes group was significantly higher than that of the control group (0.4 ± 0.1 mA). Diabetic patients with peripheral neuropathy had a higher electrical stimulation threshold (1.2 ± 0.7 mA) than patients without peripheral neuropathy (0.4 ± 0.1 mA). Furthermore, the electrical stimulation threshold of the sciatic nerve in diabetic patients had a linear dependence on the Toronto Clinical Scoring System (TCSS) peripheral neuropathy score (electrical stimulation threshold [in mA] = 0.125 TCSS score) (P < 0.001). CONCLUSION The threshold of electrical stimulation to elicit a motor response of the sciatic nerve was increased in diabetic patients, and the threshold of electrical stimulation of the sciatic nerve increased with the severity of diabetic nerve dysfunction.
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Affiliation(s)
- Guang Ying Zhang
- Department of Anesthesiology, The First Affiliated Hospital of Guangxi Medical University, Nanning, People’s Republic of China
| | - Yi Feng Chen
- Department of Anesthesiology, The First Affiliated Hospital of Guangxi Medical University, Nanning, People’s Republic of China
| | - Wei Xin Dai
- Department of Anesthesiology, The First Affiliated Hospital of Guangxi Medical University, Nanning, People’s Republic of China
| | - Dan Zhang
- Department of Anesthesiology, The First Affiliated Hospital of Guangxi Medical University, Nanning, People’s Republic of China
| | - Yi Huang
- Department of Anesthesiology, The First Affiliated Hospital of Guangxi Medical University, Nanning, People’s Republic of China
| | - Wen Zheng He
- Department of Anesthesiology, The First Affiliated Hospital of Guangxi Medical University, Nanning, People’s Republic of China
| | - Cheng Xin Lin
- Department of Anesthesiology, The First Affiliated Hospital of Guangxi Medical University, Nanning, People’s Republic of China
- Correspondence: Cheng Xin Lin; Wen Zheng He Department of Anesthesiology, The First Affiliated Hospital of Guangxi Medical University, No. 6 Shuangyong Road, Qingxiuqu, Nanning530022, People’s Republic of China Email ;
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Tummanapalli SS, Issar T, Kwai N, Pisarcikova J, Poynten AM, Krishnan AV, Willcox MDP, Markoulli M. A Comparative Study on the Diagnostic Utility of Corneal Confocal Microscopy and Tear Neuromediator Levels in Diabetic Peripheral Neuropathy. Curr Eye Res 2019; 45:921-930. [DOI: 10.1080/02713683.2019.1705984] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
| | - Tushar Issar
- Prince of Wales Clinical School, University of New South Wales, Sydney, Australia
| | - Natalie Kwai
- Prince of Wales Clinical School, University of New South Wales, Sydney, Australia
| | - Jana Pisarcikova
- School of Optometry & Vision Science, University of New South Wales, Sydney, Australia
| | - Ann M. Poynten
- Department of Endocrinology, Prince of Wales Hospital, Sydney, Australia
| | - Arun V. Krishnan
- Prince of Wales Clinical School, University of New South Wales, Sydney, Australia
| | - Mark D. P. Willcox
- School of Optometry & Vision Science, University of New South Wales, Sydney, Australia
| | - Maria Markoulli
- School of Optometry & Vision Science, University of New South Wales, Sydney, Australia
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18
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Kamel J, Loh M, Cook M, MacIsaac RJ, Roberts LJ. Reducing glucose variability with continuous subcutaneous insulin infusion is associated with reversal of axonal dysfunction in type 1 diabetes mellitus. Muscle Nerve 2019; 61:44-51. [DOI: 10.1002/mus.26738] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 09/30/2019] [Accepted: 10/09/2019] [Indexed: 01/20/2023]
Affiliation(s)
- Jordan Kamel
- Department of Neurology and Neurological Research St Vincent's Hospital Melbourne Melbourne Victoria Australia
- Department of Medicine The University of Melbourne Victoria Australia
| | - Margaret Loh
- Department of Endocrinology and Diabetes St Vincent's Hospital Melbourne Victoria Australia
| | - Mark Cook
- Department of Neurology and Neurological Research St Vincent's Hospital Melbourne Melbourne Victoria Australia
- Department of Medicine The University of Melbourne Victoria Australia
| | - Richard J. MacIsaac
- Department of Medicine The University of Melbourne Victoria Australia
- Department of Endocrinology and Diabetes St Vincent's Hospital Melbourne Victoria Australia
| | - Leslie J. Roberts
- Department of Neurology and Neurological Research St Vincent's Hospital Melbourne Melbourne Victoria Australia
- Department of Medicine The University of Melbourne Victoria Australia
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19
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Issar T, Arnold R, Kwai NCG, Walker S, Yan A, Borire AA, Poynten AM, Pussell BA, Endre ZH, Kiernan MC, Krishnan AV. Relative contributions of diabetes and chronic kidney disease to neuropathy development in diabetic nephropathy patients. Clin Neurophysiol 2019; 130:2088-2095. [PMID: 31541986 DOI: 10.1016/j.clinph.2019.08.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/04/2019] [Accepted: 08/12/2019] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Chronic kidney disease (CKD) caused by diabetes is known as diabetic kidney disease (DKD). The present study aimed to examine the underlying mechanisms of axonal dysfunction and features of neuropathy in DKD compared to CKD and type 2 diabetes (T2DM) alone. METHODS Patients with DKD (n = 30), CKD (n = 28) or T2DM (n = 40) and healthy controls (n = 41) underwent nerve excitability assessments to examine axonal function. Neuropathy was assessed using the Total Neuropathy Score. A validated mathematical model of human axons was utilised to provide an indication of the underlying causes of nerve pathophysiology. RESULTS Total neuropathy score was significantly higher in patients with DKD compared to those with either CKD or T2DM (p < 0.05). In DKD, nerve excitability measures (S2 accommodation and superexcitability, p < 0.05) were more severely affected compared to both CKD and T2DM and worsened with increasing serum K+ (p < 0.01). Mathematical modelling indicated the basis for nerve dysfunction in DKD was an elevation of extracellular K+ and reductions in Na+ permeability and the hyperpolarisation-activated cation current, which was similar to CKD. CONCLUSIONS Patients with DKD manifested a more severe neuropathy phenotype and shared features of nerve dysfunction to that of CKD. SIGNIFICANCE The CKD, and not diabetes component, appears to underlie axonal pathophysiology in DKD.
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Affiliation(s)
- Tushar Issar
- Prince of Wales Clinical School, UNSW Sydney, NSW 2031, Australia
| | - Ria Arnold
- School of Medical Sciences, UNSW Sydney, NSW 2052, Australia
| | - Natalie C G Kwai
- Prince of Wales Clinical School, UNSW Sydney, NSW 2031, Australia; Department of Exercise Physiology, UNSW Sydney, NSW 2052, Australia
| | - Susan Walker
- Prince of Wales Clinical School, UNSW Sydney, NSW 2031, Australia
| | - Aimy Yan
- Prince of Wales Clinical School, UNSW Sydney, NSW 2031, Australia
| | - Adeniyi A Borire
- Prince of Wales Clinical School, UNSW Sydney, NSW 2031, Australia
| | - Ann M Poynten
- Department of Endocrinology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
| | - Bruce A Pussell
- Department of Nephrology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
| | - Zoltan H Endre
- Department of Nephrology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
| | - Matthew C Kiernan
- Brain and Mind Centre, University of Sydney and Royal Prince Alfred Hospital, Sydney, NSW 2050, Australia
| | - Arun V Krishnan
- Prince of Wales Clinical School, UNSW Sydney, NSW 2031, Australia.
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20
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Kiernan MC, Bostock H, Park SB, Kaji R, Krarup C, Krishnan AV, Kuwabara S, Lin CSY, Misawa S, Moldovan M, Sung J, Vucic S, Wainger BJ, Waxman S, Burke D. Measurement of axonal excitability: Consensus guidelines. Clin Neurophysiol 2019; 131:308-323. [PMID: 31471200 DOI: 10.1016/j.clinph.2019.07.023] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 07/17/2019] [Accepted: 07/24/2019] [Indexed: 12/12/2022]
Abstract
Measurement of axonal excitability provides an in vivo indication of the properties of the nerve membrane and of the ion channels expressed on these axons. Axonal excitability techniques have been utilised to investigate the pathophysiological mechanisms underlying neurological diseases. This document presents guidelines derived for such studies, based on a consensus of international experts, and highlights the potential difficulties when interpreting abnormalities in diseased axons. The present manuscript provides a state-of-the-art review of the findings of axonal excitability studies and their interpretation, in addition to suggesting guidelines for the optimal performance of excitability studies.
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Affiliation(s)
- Matthew C Kiernan
- Brain and Mind Centre, University of Sydney and Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney 2006, Australia.
| | - Hugh Bostock
- UCL Queen Square Institute of Neurology, London WC1N 3BG, United Kingdom
| | - Susanna B Park
- Brain and Mind Centre, University of Sydney and Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney 2006, Australia
| | - Ryuji Kaji
- National Utano Hospital, 8-Narutaki Ondoyamacho, Ukyoku, Kyoto 616-8255, Japan
| | - Christian Krarup
- Department of Neuroscience, University of Copenhagen and Department of Clinical Neurophysiology, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Arun V Krishnan
- Prince of Wales Clinical School, University of New South Wales, Sydney, Australia
| | - Satoshi Kuwabara
- Department of Neurology, Graduate School of Medicine, Chiba University, Japan
| | - Cindy Shin-Yi Lin
- Brain and Mind Centre, University of Sydney and Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney 2006, Australia
| | - Sonoko Misawa
- Department of Neurology, Graduate School of Medicine, Chiba University, Japan
| | - Mihai Moldovan
- Department of Neuroscience, University of Copenhagen and Department of Clinical Neurophysiology, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Jiaying Sung
- Taipei Medical University, Wanfang Hospital, Taipei, Taiwan
| | - Steve Vucic
- Department of Neurology, Westmead Hospital, Western Clinical School, University of Sydney, Australia
| | - Brian J Wainger
- Department of Neurology and Anesthesiology, Critical Care & Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Stephen Waxman
- Department of Neurology, Yale Medical School, New Haven, CT 06510, USA; Neurorehabilitation Research Center, Veterans Affairs Hospital, West Haven, CT 06516, USA
| | - David Burke
- Brain and Mind Centre, University of Sydney and Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney 2006, Australia
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Kovalchuk MO, Franssen H, Scheijmans FEV, Van Schelven LJ, Van Den Berg LH, Sleutjes BTHM. Warming nerves for excitability testing. Muscle Nerve 2019; 60:279-285. [PMID: 31241195 DOI: 10.1002/mus.26621] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 06/21/2019] [Accepted: 06/23/2019] [Indexed: 11/07/2022]
Abstract
INTRODUCTION The aim of this study was to find the best method of warming the median nerve before excitability testing to a standard temperature. METHODS In 5 healthy subjects, the forearm and hand were warmed for 1 h to 37°C by infrared lamp, water blanket, or water bath. Recordings were performed before and during warming every 10 min. Excitability indices were fitted by exponential relations, thereby calculating the time needed to reach 95% of their asymptotic end value. RESULTS Distal motor latency, refractory period, and superexcitability at 10 ms changed exponentially with time. Warming by water bath took the shortest time (24 min); this was followed by warming by infrared lamp (34 min) and water blanket (35 min). CONCLUSIONS Warming by water bath is the quickest way. The other methods took only moderately more time. Future studies need to specify both warming method and warming time before excitability testing. Muscle Nerve, 2019.
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Affiliation(s)
- Maria O Kovalchuk
- Department of Neurology, University Medical Center Utrecht, Brain Center, Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Hessel Franssen
- Department of Neurology, University Medical Center Utrecht, Brain Center, Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Féline E V Scheijmans
- Department of Neurology, University Medical Center Utrecht, Brain Center, Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Leonard J Van Schelven
- Department of Medical Technology and Clinical Physics, University Medical Center Utrecht, The Netherlands
| | - Leonard H Van Den Berg
- Department of Neurology, University Medical Center Utrecht, Brain Center, Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Boudewijn T H M Sleutjes
- Department of Neurology, University Medical Center Utrecht, Brain Center, Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
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Early Detection of Diabetic Polyneuropathy Using Paired Stimulation Studies of the Sensory Nerves. Am J Phys Med Rehabil 2019; 98:982-988. [DOI: 10.1097/phm.0000000000001229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Gencpinar P, Çelmeli G, Duman Ö, Haspolat Ş, Uysal H. Tibial nerve axonal excitability in type 1 diabetes mellitus. Muscle Nerve 2018; 59:76-81. [DOI: 10.1002/mus.26303] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 07/07/2018] [Accepted: 07/10/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Pinar Gencpinar
- Department of Pediatric Neurology; Izmir Katip Celebi University, Tepecik Training and Research Hospital; Izmir Turkey
| | - Gamze Çelmeli
- Department of Pediatric Endocrinology; Akdeniz University Hospital; Antalya Turkey
| | - Özgür Duman
- Department of Pediatric Neurology; Akdeniz University Hospital; Antalya Turkey
| | - Şenay Haspolat
- Department of Pediatric Neurology; Akdeniz University Hospital; Antalya Turkey
| | - Hilmi Uysal
- Department of Neurology; Akdeniz University Hospital; 07070 Konyaaltı Antalya Turkey
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Borire AA, Issar T, Kwai NC, Visser LH, Simon NG, Poynten AM, Kiernan MC, Krishnan AV. Correlation between markers of peripheral nerve function and structure in type 1 diabetes. Diabetes Metab Res Rev 2018; 34:e3028. [PMID: 29858541 DOI: 10.1002/dmrr.3028] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 05/20/2018] [Accepted: 05/28/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND Clinical and experimental studies in patients with type 1 and type 2 diabetes have demonstrated changes in ion channel function and nerve structure. In this study, we investigated the relationship between axonal dysfunction and morphological change in diabetic polyneuropathy by using neuromuscular ultrasound and nerve excitability techniques. We also explored possible differences in this relationship between type 1 and type 2 diabetes. METHODS Nerve ultrasound and corresponding motor excitability studies were undertaken in 110 diabetes patients (50 type 1; 60 type 2) and 60 age-matched controls (30 for each group). Neuropathy severity was assessed by using total neuropathy score. Median and tibial nerve cross-sectional areas were measured at nonentrapment sites by using high-resolution linear probe. RESULTS Median and tibial nerve cross-sectional areas were significantly higher in diabetes patients compared with controls: type 1 (median = 7.6 ± 0.2 mm2 vs 6.3 ± 0.1 mm2 ; tibial = 14.5 ± 0.7 mm2 vs 10.8 ± 0.3 mm2 , P < .05) and type 2 (median = 9.1 ± 0.3 mm2 vs 7.2 ± 0.1 mm2 ; tibial = 18.5 ± 1.0 mm2 vs 12.8 ± 0.5 mm2 , P < .05). In the type 1 cohort, significant correlations were found between nerve cross-sectional area and excitability parameters including resting current-threshold slope (median: r = 0.523, P < .0001; tibial: r = -0.571, P = .004) and depolarizing threshold electrotonus at 90 to 100 ms (median: 0.424, P < .01; tibial: r = 0.435, P = .030). In contrast, there was no relationship between excitability values and nerve cross-sectional area in the type 2 cohort. CONCLUSIONS This study has identified correlation between markers of axonal membrane function and structural abnormalities in peripheral nerves of type 1 diabetes patients. The differential relationship in nerve function and structure between type 1 and type 2 diabetes provides clinical evidence that different pathophysiological mechanisms underlie the development of neuropathy in these patient groups.
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Affiliation(s)
- Adeniyi A Borire
- University of New South Wales, Prince of Wales Clinical School, Sydney, New South Wales, Australia
| | - Tushar Issar
- University of New South Wales, Prince of Wales Clinical School, Sydney, New South Wales, Australia
| | - Natalie C Kwai
- University of New South Wales, School of Medical Sciences, Sydney, New South Wales, Australia
| | - Leo H Visser
- St Elisabeth Ziekenhuis, Tilburg, The Netherlands
| | - Neil G Simon
- University of New South Wales, St Vincent's Clinical School, Sydney, New South Wales, Australia
- University of Sydney, Brain and Mind Centre, Sydney, New South Wales, Australia
| | - Ann M Poynten
- Prince of Wales Hospital, Department of Endocrinology, Sydney, New South Wales, Australia
| | - Matthew C Kiernan
- University of Sydney, Brain and Mind Centre, Sydney, New South Wales, Australia
| | - Arun V Krishnan
- University of New South Wales, Prince of Wales Clinical School, Sydney, New South Wales, Australia
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Borg-Stein J, Osoria HL, Hayano T. Regenerative Sports Medicine: Past, Present, and Future (Adapted From the PASSOR Legacy Award Presentation; AAPMR; October 2016). PM R 2018; 10:1083-1105. [PMID: 30031963 DOI: 10.1016/j.pmrj.2018.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 07/06/2018] [Indexed: 12/14/2022]
Abstract
Regenerative medicine has shown dramatic expanse and evolution in the past decade. Within that milieu, physiatrists are taking an active role in research, clinical care delivery, and education. The purpose of this review is to provide a balance among evidence, theory, experience, clinical trends, and the foreseeable future. We focus on the literature that reports the research with the best methodology in each practice area, recognizing that the level of evidence varies substantially among different treatment modalities and conditions. The following elements are included: an overview of the evolution of currently available regenerative techniques, evidence base for each available modality (prolotherapy, platelet rich plasma, bone marrow aspirate concentrate and stem cells, adipose-derived stem cells, and amniotic tissue products), general principles in the application of these treatments, and discussion and a vision of what lies ahead. We expect that practitioners will use this review to facilitate clinical decision making and to provide a core knowledge base to assist when counseling patients. LEVEL OF EVIDENCE: IV.
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Affiliation(s)
- Joanne Borg-Stein
- Spaulding Newton Wellesley Rehab Hospital Rehabilitation Center, 65 Walnut St, Wellesley, MA 02481
| | | | - Todd Hayano
- Spaulding Rehabilitation Hospital, Charlestown, MA
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Weerasinghe D, Menon P, Vucic S. Hyperpolarization-activated cyclic-nucleotide-gated channels potentially modulate axonal excitability at different thresholds. J Neurophysiol 2017; 118:3044-3050. [PMID: 28904107 DOI: 10.1152/jn.00576.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/06/2017] [Accepted: 09/12/2017] [Indexed: 11/22/2022] Open
Abstract
Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels mediate differences in sensory and motor axonal excitability at different thresholds in animal models. Importantly, HCN channels are responsible for voltage-gated inward rectifying (Ih) currents activated during hyperpolarization. The Ih currents exert a crucial role in determining the resting membrane potential and have been implicated in a variety of neurological disorders, including neuropathic pain. In humans, differences in biophysical properties of motor and sensory axons at different thresholds remain to be elucidated and could provide crucial pathophysiological insights in peripheral neurological diseases. Consequently, the aim of this study was to characterize sensory and motor axonal function at different threshold. Median nerve motor and sensory axonal excitability studies were undertaken in 15 healthy subjects (45 studies in total). Tracking targets were set to 20, 40, and 60% of maximum for sensory and motor axons. Hyperpolarizing threshold electrotonus (TEh) at 90-100 ms was significantly increased in lower threshold sensory axons times (F = 11.195, P < 0.001). In motor axons, the hyperpolarizing current/threshold (I/V) gradient was significantly increased in lower threshold axons (F = 3.191, P < 0.05). The minimum I/V gradient was increased in lower threshold motor and sensory axons. In conclusion, variation in the kinetics of HCN isoforms could account for the findings in motor and sensory axons. Importantly, assessing the function of HCN channels in sensory and motor axons of different thresholds may provide insights into the pathophysiological processes underlying peripheral neurological diseases in humans, particularly focusing on the role of HCN channels with the potential of identifying novel treatment targets.NEW & NOTEWORTHY Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels, which underlie inward rectifying currents (Ih), appear to mediate differences in sensory and motor axonal properties. Inward rectifying currents are increased in lower threshold motor and sensory axons, although different HCN channel isoforms appear to underlie these changes. While faster activating HCN channels seem to underlie Ih changes in sensory axons, slower activating HCN isoforms appear to be mediating the differences in Ih conductances in motor axons of different thresholds. The differences in HCN gating properties could explain the predilection for dysfunction of sensory and motor axons in specific neurological diseases.
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Affiliation(s)
| | - Parvathi Menon
- Department of Neurology, Westmead Hospital, Sydney, Australia; and.,Westmead Clinical School, The University of Sydney, Sydney, Australia
| | - Steve Vucic
- Department of Neurology, Westmead Hospital, Sydney, Australia; and .,Westmead Clinical School, The University of Sydney, Sydney, Australia
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27
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Presynaptic inhibition of nociceptive neurotransmission by somatosensory neuron-secreted suppressors. SCIENCE CHINA-LIFE SCIENCES 2017. [PMID: 28624955 DOI: 10.1007/s11427-017-9061-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Noxious stimuli cause pain by activating cutaneous nociceptors. The Aδ- and C-fibers of dorsal root ganglion (DRG) neurons convey the nociceptive signals to the laminae I-II of spinal cord. In the dorsal horn of spinal cord, the excitatory afferent synaptic transmission is regulated by the inhibitory neurotransmitter γ-aminobutyric acid and modulators such as opioid peptides released from the spinal interneurons, and by serotonin, norepinepherine and dopamine from the descending inhibitory system. In contrast to the accumulated evidence for these central inhibitors and their neural circuits in the dorsal spinal cord, the knowledge about the endogenous suppressive mechanisms in nociceptive DRG neurons remains very limited. In this review, we summarize our recent findings of the presynaptic suppressive mechanisms in nociceptive neurons, the BNP/NPR-A/PKG/BKCa channel pathway, the FSTL1/α1Na+-K+ ATPase pathway and the activin C/ERK pathway. These endogenous suppressive systems in the mechanoheat nociceptors may also contribute differentially to the mechanisms of nerve injury-induced neuropathic pain or inflammation-induced pain.
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28
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Zhao M, Liao D, Zhao J. Diabetes-induced mechanophysiological changes in the small intestine and colon. World J Diabetes 2017; 8:249-269. [PMID: 28694926 PMCID: PMC5483424 DOI: 10.4239/wjd.v8.i6.249] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 04/05/2017] [Accepted: 05/05/2017] [Indexed: 02/05/2023] Open
Abstract
The disorders of gastrointestinal (GI) tract including intestine and colon are common in the patients with diabetes mellitus (DM). DM induced intestinal and colonic structural and biomechanical remodeling in animals and humans. The remodeling is closely related to motor-sensory abnormalities of the intestine and colon which are associated with the symptoms frequently encountered in patients with DM such as diarrhea and constipation. In this review, firstly we review DM-induced histomorphological and biomechanical remodeling of intestine and colon. Secondly we review motor-sensory dysfunction and how they relate to intestinal and colonic abnormalities. Finally the clinical consequences of DM-induced changes in the intestine and colon including diarrhea, constipation, gut microbiota change and colon cancer are discussed. The final goal is to increase the understanding of DM-induced changes in the gut and the subsequent clinical consequences in order to provide the clinicians with a better understanding of the GI disorders in diabetic patients and facilitates treatments tailored to these patients.
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29
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Sung JY, Tani J, Chang TS, Lin CSY. Uncovering sensory axonal dysfunction in asymptomatic type 2 diabetic neuropathy. PLoS One 2017; 12:e0171223. [PMID: 28182728 PMCID: PMC5300160 DOI: 10.1371/journal.pone.0171223] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 01/17/2017] [Indexed: 12/02/2022] Open
Abstract
This study investigated sensory and motor nerve excitability properties to elucidate the development of diabetic neuropathy. A total of 109 type 2 diabetes patients were recruited, and 106 were analyzed. According to neuropathy severity, patients were categorized into G0, G1, and G2+3 groups using the total neuropathy score-reduced (TNSr). Patients in the G0 group were asymptomatic and had a TNSr score of 0. Sensory and motor nerve excitability data from diabetic patients were compared with data from 33 healthy controls. Clinical assessment, nerve conduction studies, and sensory and motor nerve excitability testing data were analyzed to determine axonal dysfunction in diabetic neuropathy. In the G0 group, sensory excitability testing revealed increased stimulus for the 50% sensory nerve action potential (P<0.05), shortened strength-duration time constant (P<0.01), increased superexcitability (P<0.01), decreased subexcitability (P<0.05), decreased accommodation to depolarizing current (P<0.01), and a trend of decreased accommodation to hyperpolarizing current in threshold electrotonus. All the changes progressed into G1 (TNSr 1–8) and G2+3 (TNSr 9–24) groups. In contrast, motor excitability only had significantly increased stimulus for the 50% compound motor nerve action potential (P<0.01) in the G0 group. This study revealed that the development of axonal dysfunction in sensory axons occurred prior to and in a different fashion from motor axons. Additionally, sensory nerve excitability tests can detect axonal dysfunction even in asymptomatic patients. These insights further our understanding of diabetic neuropathy and enable the early detection of sensory axonal abnormalities, which may provide a basis for neuroprotective therapeutic approaches.
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Affiliation(s)
- Jia-Ying Sung
- Department of Neurology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.,Department of Neurology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Jowy Tani
- Department of Neurology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.,Ph.D. Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes
| | - Tsui-San Chang
- Department of Neurology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Cindy Shin-Yi Lin
- Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes.,Translational Neuroscience, Department of Physiology, School of Medicine Science, Faculty of Medicine, University of New South Wales, Sydney, Australia
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30
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Brock C, Brock B, Pedersen AG, Drewes AM, Jessen N, Farmer AD. Assessment of the cardiovascular and gastrointestinal autonomic complications of diabetes. World J Diabetes 2016; 7:321-332. [PMID: 27625746 PMCID: PMC4999648 DOI: 10.4239/wjd.v7.i16.321] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 04/08/2016] [Accepted: 06/03/2016] [Indexed: 02/05/2023] Open
Abstract
The global prevalence of diabetes mellitus is increasing; arguably as a consequence of changes in diet, lifestyle and the trend towards urbanization. Unsurprisingly, the incidence of both micro and macrovascular complications of diabetes mirrors this increasing prevalence. Amongst the complications with the highest symptom burden, yet frequently under-diagnosed and sub-optimally treated, is diabetic autonomic neuropathy, itself potentially resulting in cardiovascular autonomic neuropathy and gastrointestinal (GI) tract dysmotility. The aims of this review are fourfold. Firstly to provide an overview of the pathophysiological processes that cause diabetic autonomic neuropathy. Secondly, to discuss both the established and emerging cardiometric methods for evaluating autonomic nervous system function in vivo. Thirdly, to examine the tools for assessing pan-GI and segmental motility and finally, we will provide the reader with a summary of putative non-invasive biomarkers that provide a pathophysiological link between low-grade neuro inflammation and diabetes, which may allow earlier diagnosis and intervention, which in future may improve patient outcomes.
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31
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Zhao J, Gregersen H. Diabetes-induced mechanophysiological changes in the esophagus. Ann N Y Acad Sci 2016; 1380:139-154. [PMID: 27495976 DOI: 10.1111/nyas.13180] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/17/2016] [Accepted: 06/20/2016] [Indexed: 12/13/2022]
Abstract
Esophageal disorders are common in diabetes mellitus (DM) patients. DM induces mechanostructural remodeling in the esophagus of humans and animal models. The remodeling is related to esophageal sensorimotor abnormalities and to symptoms frequently encountered by DM patients. For example, gastroesophageal reflux disease (GERD) is a common disorder associated with DM. This review addresses diabetic remodeling of esophageal properties and function in light of the Esophagiome, a scientifically based modeling effort to describe the physiological dynamics of the normal, intact esophagus built upon interdisciplinary approaches with applications for esophageal disease. Unraveling the structural, biomechanical, and sensory remodeling of the esophagus in DM must be based on a multidisciplinary approach that can bridge the knowledge from a variety of scientific disciplines. The first focus of this review is DM-induced morphodynamic and biomechanical remodeling in the esophagus. Second, we review the sensorimotor dysfunction in DM and how it relates to esophageal remodeling. Finally, we discuss the clinical consequences of DM-induced esophageal remodeling, especially in relation to GERD. The ultimate aim is to increase the understanding of DM-induced remodeling of esophageal structure and sensorimotor function in order to assist clinicians to better understand the esophageal disorders induced by DM and to develop better treatments for those patients.
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Affiliation(s)
- Jingbo Zhao
- Giome Academia, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
| | - Hans Gregersen
- GIOME, Department of Surgery, Prince of Wales Hospital and Chinese University of Hong Kong, Shatin, Hong Kong SAR.,GIOME, College of Bioengineering, Chongqing University, Chongqing, China
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32
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Akça G, Yerdelen D, Balcı MK, Uysal H. The effects of hyperventilation on axonal excitability parameters in patients with diabetes mellitus and polyneuropathy. Diabetes Res Clin Pract 2016; 118:112-20. [PMID: 27368063 DOI: 10.1016/j.diabres.2016.04.058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 04/25/2016] [Accepted: 04/30/2016] [Indexed: 11/29/2022]
Abstract
AIMS We aimed to explore axonal excitability parameters in patients with diabetes mellitus (DM) and polyneuropathy (PNP) as well as those without PNP. METHODS We used the short TROND protocol by QTRAC to measure axonal excitability parameters (strength-duration time constant (SDTC), rheobase, etc.) in 12 healthy subjects and 14 DM patients with PNP and 10 DM patients without PNP. The short TROND protocol was performed before and after 20min of deep hyperventilation in healthy subjects and patients with DM. Also, venous blood pH and partial pressure of O2 and CO2 were recorded before hyperventilation (HPV) and after 20min of HPV. A "hyperventilation score" was evaluated before and after HPV. RESULTS When the values of DM with PNP group and control group before HPV were compared, SDTC and latency were statistically significant. Comparing the values of the excitability parameters after HPV showed statistically significant changes in the SDTC, rheobase, and refractoriness at 2.5ms in controls and DM patients without PNP. HPV resulted in no changes in SDTC in DM patients with PNP. CONCLUSION The results of this study suggest that patients with DM and healthy subjects have different responses to HPV, and pH changes have different effects on diabetic PNP compared with healthy controls and DM patients without PNP.
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Affiliation(s)
- Gökçen Akça
- Akdeniz University Faculty of Medicine, Department of Neurology, Antalya, Turkey
| | - Deniz Yerdelen
- Başkent University Faculty of Medicine, Department of Neurology, Adana, Turkey
| | - Mustafa Kemal Balcı
- Akdeniz University Faculty of Medicine, Department of Internal Medicine and Endocrinology, Antalya, Turkey
| | - Hilmi Uysal
- Akdeniz University Faculty of Medicine, Department of Neurology, Antalya, Turkey
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33
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Heschl S, Hallmann B, Zilke T, Gemes G, Schoerghuber M, Auer-Grumbach M, Quehenberger F, Lirk P, Hogan Q, Rigaud M. Diabetic neuropathy increases stimulation threshold during popliteal sciatic nerve block. Br J Anaesth 2016; 116:538-45. [PMID: 26994231 PMCID: PMC4797685 DOI: 10.1093/bja/aew027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Peripheral nerve stimulation is commonly used for nerve localization in regional anaesthesia, but recommended stimulation currents of 0.3-0.5 mA do not reliably produce motor activity in the absence of intraneural needle placement. As this may be particularly true in patients with diabetic neuropathy, we examined the stimulation threshold in patients with and without diabetes. METHODS Preoperative evaluation included a neurological exam and electroneurography. During ultrasound-guided popliteal sciatic nerve block, we measured the current required to produce motor activity for the tibial and common peroneal nerve in diabetic and non-diabetic patients. Proximity to the nerve was evaluated post-hoc using ultrasound imaging. RESULTS Average stimulation currents did not differ between diabetic (n=55) and non-diabetic patients (n=52). Although the planned number of patients was not reached, the power goal for the mean stimulation current was met. Subjects with diminished pressure perception showed increased thresholds for the common peroneal nerve (median 1.30 vs. 0.57 mA in subjects with normal perception, P=0.042), as did subjects with decreased pain sensation (1.60 vs. 0.50 mA in subjects with normal sensation, P=0.038). Slowed ulnar nerve conduction velocity predicted elevated mean stimulation current (r=-0.35, P=0.002). Finally, 15 diabetic patients required more than 0.5 mA to evoke a motor response, despite intraneural needle placement (n=4), or required currents ≥2 mA despite needle-nerve contact, vs three such patients (1 intraneural, 2 with ≥2 mA) among non-diabetic patients (P=0.003). CONCLUSIONS These findings suggest that stimulation thresholds of 0.3-0.5 mA may not reliably determine close needle-nerve contact during popliteal sciatic nerve block, particularly in patients with diabetic neuropathy. CLINICAL TRIAL REGISTRATION NCT01488474.
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Affiliation(s)
- S Heschl
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 29/I, Graz 8036, Austria
| | - B Hallmann
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 29/I, Graz 8036, Austria
| | - T Zilke
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 29/I, Graz 8036, Austria
| | - G Gemes
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 29/I, Graz 8036, Austria
| | - M Schoerghuber
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 29/I, Graz 8036, Austria
| | - M Auer-Grumbach
- Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, Graz 8036, Austria
| | - F Quehenberger
- Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Auenbruggerplatz 2, Graz 8036, Austria
| | - P Lirk
- Department of Anaesthesiology, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, Amsterdam 1105AZ, The Netherlands
| | - Q Hogan
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - M Rigaud
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 29/I, Graz 8036, Austria
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34
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Allen MD, Doherty TJ, Rice CL, Kimpinski K. Physiology in Medicine: neuromuscular consequences of diabetic neuropathy. J Appl Physiol (1985) 2016; 121:1-6. [PMID: 26989220 DOI: 10.1152/japplphysiol.00733.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 03/17/2016] [Indexed: 02/07/2023] Open
Abstract
Diabetic polyneuropathy (DPN) refers to peripheral nerve dysfunction as a complication of diabetes mellitus. This condition is relatively common and is likely a result of vascular and/or metabolic disturbances related to diabetes. In the early or less severe stages of DPN it typically results in sensory impairments but can eventually lead to major dysfunction of the neuromuscular system. Some of these impairments may include muscle atrophy and weakness, slowing of muscle contraction, and loss of power and endurance. Combined with sensory deficits these changes in the motor system can contribute to decreased functional capacity, impaired mobility, altered gait, and increased fall risk. There is no pharmacological disease-modifying therapy available for DPN and the mainstay of treatment is linked to treating the diabetes itself and revolves around strict glycemic control. Exercise therapy (including aerobic, strength, or balance training-based exercise) appears to be a promising preventative and treatment strategy for patients with DPN and those at risk. The goal of this Physiology in Medicine article is to highlight important and overlooked dysfunction of the neuromuscular system as a result of DPN with an emphasis on the physiologic basis for that dysfunction. Additionally, we sought to provide information that clinicians can use when following patients with diabetes or DPN including support for the inclusion of exercise-based therapy as an effective, accessible, and inexpensive form of treatment.
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Affiliation(s)
- Matti D Allen
- School of Medicine, Queen's University, Kingston, Ontario, Canada; School of Kinesiology and Health Studies, Faculty of Health Sciences, Queen's University, Kingston, Ontario, Canada; School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada;
| | - Timothy J Doherty
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada; Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada; Department of Physical Medicine and Rehabilitation, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada; and
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada; Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Kurt Kimpinski
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
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35
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Tigerholm J, Petersson ME, Obreja O, Eberhardt E, Namer B, Weidner C, Lampert A, Carr RW, Schmelz M, Fransén E. C-fiber recovery cycle supernormality depends on ion concentration and ion channel permeability. Biophys J 2016; 108:1057-71. [PMID: 25762318 DOI: 10.1016/j.bpj.2014.12.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 11/30/2014] [Accepted: 12/17/2014] [Indexed: 12/20/2022] Open
Abstract
Following each action potential, C-fiber nociceptors undergo cyclical changes in excitability, including a period of superexcitability, before recovering their basal excitability state. The increase in superexcitability during this recovery cycle depends upon their immediate firing history of the axon, but also determines the instantaneous firing frequency that encodes pain intensity. To explore the mechanistic underpinnings of the recovery cycle phenomenon a biophysical model of a C-fiber has been developed. The model represents the spatial extent of the axon including its passive properties as well as ion channels and the Na/K-ATPase ion pump. Ionic concentrations were represented inside and outside the membrane. The model was able to replicate the typical transitions in excitability from subnormal to supernormal observed empirically following a conducted action potential. In the model, supernormality depended on the degree of conduction slowing which in turn depends upon the frequency of stimulation, in accordance with experimental findings. In particular, we show that activity-dependent conduction slowing is produced by the accumulation of intraaxonal sodium. We further show that the supernormal phase results from a reduced potassium current Kdr as a result of accumulation of periaxonal potassium in concert with a reduced influx of sodium through Nav1.7 relative to Nav1.8 current. This theoretical prediction was supported by data from an in vitro preparation of small rat dorsal root ganglion somata showing a reduction in the magnitude of tetrodotoxin-sensitive relative to tetrodotoxin -resistant whole cell current. Furthermore, our studies provide support for the role of depolarization in supernormality, as previously suggested, but we suggest that the basic mechanism depends on changes in ionic concentrations inside and outside the axon. The understanding of the mechanisms underlying repetitive discharges in recovery cycles may provide insight into mechanisms of spontaneous activity, which recently has been shown to correlate to a perceived level of pain.
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Affiliation(s)
- Jenny Tigerholm
- Department of Computational Biology, School of Computer Science and Communication, KTH Royal Institute of Technology, Stockholm, Sweden; Stockholm Brain Institute, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Marcus E Petersson
- Department of Computational Biology, School of Computer Science and Communication, KTH Royal Institute of Technology, Stockholm, Sweden; Stockholm Brain Institute, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Otilia Obreja
- Anaesthesiology, Universitaetsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Esther Eberhardt
- Institute of Physiology and Pathophysiology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Barbara Namer
- Department of Anesthesiology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Christian Weidner
- Department of Anesthesiology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Angelika Lampert
- Institute of Physiology and Pathophysiology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany; Institute of Physiology, RWTH Aachen University, Aachen, Germany
| | - Richard W Carr
- Anaesthesiology, Universitaetsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Martin Schmelz
- Anaesthesiology, Universitaetsmedizin Mannheim, University of Heidelberg, Mannheim, Germany
| | - Erik Fransén
- Department of Computational Biology, School of Computer Science and Communication, KTH Royal Institute of Technology, Stockholm, Sweden; Stockholm Brain Institute, KTH Royal Institute of Technology, Stockholm, Sweden.
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Upregulation of axonal HCN current by methylglyoxal: Potential association with diabetic polyneuropathy. Clin Neurophysiol 2015; 126:2226-32. [DOI: 10.1016/j.clinph.2015.02.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 01/15/2015] [Accepted: 02/01/2015] [Indexed: 11/18/2022]
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Ghazan-Shahi S, Koh TJK, Chan CT. Impact of nocturnal hemodialysis on peripheral uremic neuropathy. BMC Nephrol 2015; 16:134. [PMID: 26264143 PMCID: PMC4534055 DOI: 10.1186/s12882-015-0133-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 07/28/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Uremic neuropathy is a common complication in patients with end stage kidney disease. Its pathogenesis has been attributed to accumulation of uremic toxins. Kidney transplantation has been the best therapeutic option. CASE PRESENTATION We describe a case of severe uremic peripheral neuropathy, which improved after conversion from a conventional renal replacement therapy to nocturnal hemodialysis. CONCLUSION Enhanced uremic control by intensive hemodialysis may contribute at least in part to clinical and neurophysiological improvements of uremic neuropathy.
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Affiliation(s)
- Sassan Ghazan-Shahi
- Department of Internal Medicine, Division of Nephrology, University Health Network Toronto General Hospital, 200 Elizabeth Street, Toronto, Ontario, M5G 2C4, Canada.
| | - Timothy Jee Kam Koh
- Department of Internal Medicine, Division of Nephrology, University Health Network Toronto General Hospital, 200 Elizabeth Street, Toronto, Ontario, M5G 2C4, Canada.
| | - Christopher T Chan
- Department of Internal Medicine, Division of Nephrology, University Health Network Toronto General Hospital, 200 Elizabeth Street, Toronto, Ontario, M5G 2C4, Canada.
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38
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Franssen H. Relation between symptoms and pathophysiology in inflammatory neuropathies: Controversies and hypotheses. Neurosci Lett 2015; 596:84-9. [PMID: 25483620 DOI: 10.1016/j.neulet.2014.12.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/11/2014] [Accepted: 12/02/2014] [Indexed: 10/24/2022]
Abstract
This review attempts to explain the symptoms experienced by patients with inflammatory neuropathies by pathophysiological events. The emphasis is not on the primary events that may cause a particular illness but on downstream events taking place in peripheral nerves or muscles. Symptoms that will be discussed include sensory predominance, motor predominance, activity-induced weakness, heat paresis, and cold paresis. Each symptom is associated with, but not limited to, particular neuropathies.
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Affiliation(s)
- Hessel Franssen
- Brain Center Rudolf Magnus, Section Neuromuscular Disorders, Department of Neurology F02.230, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, Netherlands.
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39
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Vucic S. Methylglyoxal modulates axonal excitability in diabetic polyneuropathy: A potential pathophysiological link? Clin Neurophysiol 2015; 126:2047-8. [PMID: 25836600 DOI: 10.1016/j.clinph.2015.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 03/05/2015] [Accepted: 03/06/2015] [Indexed: 11/24/2022]
Affiliation(s)
- Steve Vucic
- Westmead Clinical School, University of Sydney, Sydney, Australia.
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40
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Huynh W, Kiernan MC. Peripheral nerve axonal excitability studies: expanding the neurophysiologist's armamentarium. CEREBELLUM & ATAXIAS 2015; 2:4. [PMID: 26331047 PMCID: PMC4552150 DOI: 10.1186/s40673-015-0022-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 02/12/2015] [Indexed: 12/13/2022]
Abstract
Nerve excitability studies have emerged as a recent novel non-invasive technique that offers complementary information to that provided by more conventional nerve conduction studies, the latter which provide only limited indices of peripheral nerve function. Such novel tools allow for the assessment of peripheral axonal biophysical properties that include ion channels, energy-dependent pumps and membrane potential in health and disease. With improvements in technique and development of protocols, a typical study can be completed in a short period of time and rapid measurement of multiple excitability indices can be achieved that provide insight into different aspects of peripheral nerve function. The advent of automated protocols for the assessment of nerve excitability has promoted their use in previous studies investigating disease pathophysiology such as in metabolic, toxic and demyelinating neuropathies, amyotrophic lateral sclerosis, stroke, spinal cord injury and inherited channelopathies. In more recent years, the use of nerve excitability studies have additionally provided insights into the pathophysiological mechanisms underlying cerebellar disorders that include stroke and familial cerebellar ataxias such as episodic ataxia types 1 and 2. Moreover, this technique may have diagnostic and therapeutic implications that may encompass a broader range of neurodegenerative cerebellar ataxias in years to come. In the foreseeable future, this technique may eventually be incorporated into clinical practice expanding the currently available armamentarium to the neurophysiologist.
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Affiliation(s)
- William Huynh
- Brain and Mind Research Institute, University of Sydney, Sydney, Australia
| | - Matthew C Kiernan
- Brain and Mind Research Institute, University of Sydney, Sydney, Australia
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Impact of Hyperglycemia in the Outcome of Patients with Primary Neuromuscular Respiratory Failure. Neurocrit Care 2015; 23:103-7. [DOI: 10.1007/s12028-015-0114-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Kwai N, Arnold R, Poynten AM, Lin CSY, Kiernan MC, Krishnan AV. Continuous subcutaneous insulin infusion preserves axonal function in type 1 diabetes mellitus. Diabetes Metab Res Rev 2015; 31:175-82. [PMID: 25066412 DOI: 10.1002/dmrr.2583] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 07/17/2014] [Accepted: 07/18/2014] [Indexed: 01/22/2023]
Abstract
BACKGROUND Diabetic peripheral neuropathy is a common and debilitating complication of diabetes mellitus. Although strict glycaemic control may reduce the risk of developing diabetic peripheral neuropathy, the neurological benefits of different insulin regimens remain relatively unknown. METHODS In the present study, 55 consecutive patients with type 1 diabetes mellitus underwent clinical neurological assessment. Subsequently, 41 non-neuropathic patients, 24 of whom were receiving multiple daily insulin injections (MDII) and 17 receiving continuous subcutaneous insulin infusion (CSII), underwent nerve excitability testing, a technique that assesses axonal ion channel function and membrane potential in human nerves. Treatment groups were matched for glycaemic control, body mass index, disease duration and gender. Neurophysiological parameters were compared between treatment groups and those taken from age and sex-matched normal controls. RESULTS Prominent differences in axonal function were noted between MDII-treated and CSII-treated patients. Specifically, MDII patients manifested prominent abnormalities when compared with normal controls in threshold electrotonus (TE) parameters including depolarizing TE(10-20ms), undershoot and hyperpolarizing TE (90-100 ms) (P < 0.05). Additionally, recovery cycle parameters superexcitability and subexcitability were also abnormal (P < 0.05). In contrast, axonal function in CSII-treated patients was within normal limits when compared with age-matched controls. The differences between the groups were noted in cross-sectional analysis and remained at longitudinal follow-up. CONCLUSIONS Axonal function in type 1 diabetes is maintained within normal limits in patients treated with continuous subcutaneous insulin infusion and not with multiple daily insulin injections. This raises the possibility that CSII therapy may have neuroprotective potential in patients with type 1 diabetes.
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Affiliation(s)
- Natalie Kwai
- Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales, Sydney, Australia
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Hafner J, Ghaoui R, Coyle L, Burke D, Ng K. Axonal excitability in primary amyloidotic neuropathy. Muscle Nerve 2015; 51:443-5. [DOI: 10.1002/mus.24508] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/31/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Jessica Hafner
- Department of Neurology and Clinical Neurophysiology; Royal North Shore Hospital; Reserve Road St Leonards New South Wales 2065 Australia
| | - Roula Ghaoui
- Institute for Neuroscience and Muscle Research, Children's Hospital at Westmead; Westmead New South Wales Australia
| | - Luke Coyle
- Department of Haematology; Royal North Shore Hospital; St Leonards New South Wales Australia
| | - David Burke
- Department of Clinical Neurophysiology; Royal Prince Alfred Hospital; Camperdown New South Wales Australia
| | - Karl Ng
- Department of Neurology and Clinical Neurophysiology; Royal North Shore Hospital; Reserve Road St Leonards New South Wales 2065 Australia
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Lin CC, Chiang YS, Lung CC. Effect of infrared-C radiation on skin temperature, electrodermal conductance and pain in hemiparetic stroke patients. Int J Radiat Biol 2014; 91:42-53. [PMID: 24991883 DOI: 10.3109/09553002.2014.937512] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE A novel application of infrared-C (IR-C) radiation (3-1000 μm) on hemiparetic stroke patients was evaluated. Hot compresses (HC) were used on the paretic shoulders of patients in this placebo-controlled trial to investigate the effects of IR-C on skin temperature, electrodermal conductance (EC) and pain relief. MATERIALS AND METHODS Skin temperature at the center of the middle deltoid (CMD), Quchi (LI11), and the center of the third metacarpal bone on dorsum of hand (COT) of the subjects at Brunnstrom stage 3-5 before and after IR-C HC, were examined. Meanwhile, EC was measured on Hegu (LI4), Quchi and Juanyu (LI15). Pain intensity was evaluated before and after treatment. RESULTS Skin temperature increased significantly at the CMD and COT on the paretic side in males. In females after treatment, similar skin temperatures were found in each measured region on both the paretic and non-paretic sides. The EC on the paretic side tended to be higher than the non-paretic side before treatment. After treatment, the EC on paretic side declined in both sexes and became even lower than the non-paretic side in females. Pain intensity was lessened after treatment especially in males, which appeared to correspond with an increase in skin temperature and a decrease in EC. CONCLUSION IR-C hot compress is a promising method for stroke patients in rehabilitation. Physiological mechanisms of this treatment were proposed and summarized from this research.
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Fransén EA, Ahlström PJ. Ionic mechanisms of post spike excitability changes during high-frequency firing rates. Scand J Pain 2014. [DOI: 10.1016/j.sjpain.2014.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Abstract
Aims
Axonal hyperexcitability in peripheral nerves has been observed in patients with neuropathic pain [1]. The use-dependent propagation of double pulses, recovery cycles, was found to be different in patients relative to healthy controls.
Methods
We study the mechanisms underlying the recovery cycle phenomenon using a biophysical model of a C-fiber [2]. The model represents the spatial extent of the axon including its passive properties as well as ion channels of Hodgkin-Huxley type. In vitro voltage clamp recordings from dissociated small DRG somata from rat were performed to assess model predictions.
Results
The model was able to replicate the transitions in excitability from subnormal to supernormal observed experimentally. For the model, supernormality depended on the degree of conduction slowing which in turn depends upon the frequency of stimulation, in accordance with experimental findings. In particular, we show that activity dependent conduction slowing is produced by the accumulation of intraaxonal sodium. We further show that the supernormal phase results from a reduced potassium current Kdr as a result of accumulation of periaxonal potassium in concert with a reduced influx of sodium through Nav1.7 relative to Nav1.8 current. This theoretical prediction of a relative shift in the sodium currents was supported by data from an in vitro preparation of small rat DRG somata showing a relative reduction in the magnitude of TTX-sensitive to TTX-resistant whole cell currents.
Conclusions
By providing mechanistic explanations of axonal excitability in terms of changes in ion channel activity, we suggest these channel changes can subsequently be used to discuss mechanisms of neuropathic pain.
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Affiliation(s)
- Erik A. Fransén
- Department of Computational Biology, School of Computer Science and Communication , KTH Royal Institute of Technology , Stockholm , Sweden
- Stockholm Brain Institute, KTH Royal Institute of Technology , Stockholm , Sweden
| | - Peter J. Ahlström
- Department of Computational Biology, School of Computer Science and Communication , KTH Royal Institute of Technology , Stockholm , Sweden
- Stockholm Brain Institute, KTH Royal Institute of Technology , Stockholm , Sweden
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Arnold R, Kwai NC, Krishnan AV. Mechanisms of axonal dysfunction in diabetic and uraemic neuropathies. Clin Neurophysiol 2013; 124:2079-90. [DOI: 10.1016/j.clinph.2013.04.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 04/12/2013] [Accepted: 04/13/2013] [Indexed: 12/13/2022]
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Dyck PJ, Herrmann DN, Staff NP, Dyck PJB. Assessing decreased sensation and increased sensory phenomena in diabetic polyneuropathies. Diabetes 2013; 62:3677-86. [PMID: 24158999 PMCID: PMC3806590 DOI: 10.2337/db13-0352] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 07/25/2013] [Indexed: 12/14/2022]
Abstract
Loss of sensation and increased sensory phenomena are major expressions of varieties of diabetic polyneuropathies needing improved assessments for clinical and research purposes. We provide a neurobiological explanation for the apparent paradox between decreased sensation and increased sensory phenomena. Strongly endorsed is the use of the 10-g monofilaments for screening of feet to detect sensation loss, with the goal of improving diabetic management and prevention of foot ulcers and neurogenic arthropathy. We describe improved methods to assess for the kind, severity, and distribution of both large- and small-fiber sensory loss and which approaches and techniques may be useful for conducting therapeutic trials. The abnormality of attributes of nerve conduction may be used to validate the dysfunction of large sensory fibers. The abnormality of epidermal nerve fibers/1 mm may be used as a surrogate measure of small-fiber sensory loss but appear not to correlate closely with severity of pain. Increased sensory phenomena are recognized by the characteristic words patients use to describe them and by the severity and persistence of these symptoms. Tests of tactile and thermal hyperalgesia are additional markers of neural hyperactivity that are useful for diagnosis and disease management.
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Affiliation(s)
- Peter J. Dyck
- Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | - David N. Herrmann
- Department of Neurology, University of Rochester Medical Center, Rochester, New York
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Hofmeijer J, Franssen H, van Schelven LJ, van Putten MJAM. Why are sensory axons more vulnerable for ischemia than motor axons? PLoS One 2013; 8:e67113. [PMID: 23840596 PMCID: PMC3688630 DOI: 10.1371/journal.pone.0067113] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Accepted: 05/14/2013] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE In common peripheral neuropathies, sensory symptoms usually prevail over motor symptoms. This predominance of sensory symptoms may result from higher sensitivity of sensory axons to ischemia. METHODS We measured median nerve compound sensory action potentials (CSAPs), compound muscle action potentials (CMAPs), and excitability indices in five healthy subjects during forearm ischemia lasting up to disappearance of both CSAPs and CMAPs. RESULTS ISCHEMIA INDUCED: (1) earlier disappearance of CSAPs than CMAPs (mean ± standard deviation 30±5 vs. 46±6 minutes), (2) initial changes compatible with axonal depolarization on excitability testing (decrease in threshold, increase in strength duration time constant (SDTC) and refractory period, and decrease in absolute superexcitability) which were all more prominent in sensory than in motor axons, and (3) a subsequent decrease of SDTC reflecting a decrease in persistent Na(+) conductance during continuing depolarisation. INTERPRETATION Our study shows that peripheral sensory axons are more vulnerable for ischemia than motor axons, with faster inexcitability during ischemia. Excitability studies during ischemia showed that this was associated with faster depolarization and faster persistent Na(+) channel inactivation in sensory than in motor axons. These findings might be attributed to differences in ion channel composition between sensory and motor axons and may contribute to the predominance of sensory over motor symptoms in common peripheral neuropathies.
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Affiliation(s)
- Jeannette Hofmeijer
- Clinical Neurophysiology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands.
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Acquired neuropathies. J Neurol 2013; 260:2433-40. [DOI: 10.1007/s00415-013-6994-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/31/2013] [Accepted: 06/03/2013] [Indexed: 11/26/2022]
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