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Xie YF, Yang J, Ratté S, Prescott SA. Similar excitability through different sodium channels and implications for the analgesic efficacy of selective drugs. eLife 2024; 12:RP90960. [PMID: 38687187 PMCID: PMC11060714 DOI: 10.7554/elife.90960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024] Open
Abstract
Nociceptive sensory neurons convey pain-related signals to the CNS using action potentials. Loss-of-function mutations in the voltage-gated sodium channel NaV1.7 cause insensitivity to pain (presumably by reducing nociceptor excitability) but clinical trials seeking to treat pain by inhibiting NaV1.7 pharmacologically have struggled. This may reflect the variable contribution of NaV1.7 to nociceptor excitability. Contrary to claims that NaV1.7 is necessary for nociceptors to initiate action potentials, we show that nociceptors can achieve similar excitability using different combinations of NaV1.3, NaV1.7, and NaV1.8. Selectively blocking one of those NaV subtypes reduces nociceptor excitability only if the other subtypes are weakly expressed. For example, excitability relies on NaV1.8 in acutely dissociated nociceptors but responsibility shifts to NaV1.7 and NaV1.3 by the fourth day in culture. A similar shift in NaV dependence occurs in vivo after inflammation, impacting ability of the NaV1.7-selective inhibitor PF-05089771 to reduce pain in behavioral tests. Flexible use of different NaV subtypes exemplifies degeneracy - achieving similar function using different components - and compromises reliable modulation of nociceptor excitability by subtype-selective inhibitors. Identifying the dominant NaV subtype to predict drug efficacy is not trivial. Degeneracy at the cellular level must be considered when choosing drug targets at the molecular level.
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Affiliation(s)
- Yu-Feng Xie
- Neurosciences and Mental Health, The Hospital for Sick ChildrenTorontoCanada
| | - Jane Yang
- Neurosciences and Mental Health, The Hospital for Sick ChildrenTorontoCanada
- Institute of Biomedical Engineering, University of TorontoTorontoCanada
| | - Stéphanie Ratté
- Neurosciences and Mental Health, The Hospital for Sick ChildrenTorontoCanada
| | - Steven A Prescott
- Neurosciences and Mental Health, The Hospital for Sick ChildrenTorontoCanada
- Institute of Biomedical Engineering, University of TorontoTorontoCanada
- Department of Physiology, University of TorontoTorontoCanada
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2
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Kacem H, Cimini A, d’Angelo M, Castelli V. Molecular and Cellular Involvement in CIPN. Biomedicines 2024; 12:751. [PMID: 38672107 PMCID: PMC11048589 DOI: 10.3390/biomedicines12040751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/28/2024] Open
Abstract
Many anti-cancer drugs, such as taxanes, platinum compounds, vinca alkaloids, and proteasome inhibitors, can cause chemotherapy-induced peripheral neuropathy (CIPN). CIPN is a frequent and harmful side effect that affects the sensory, motor, and autonomic nerves, leading to pain, numbness, tingling, weakness, and reduced quality of life. The causes of CIPN are not fully known, but they involve direct nerve damage, oxidative stress, inflammation, DNA damage, microtubule dysfunction, and altered ion channel activity. CIPN is also affected by genetic, epigenetic, and environmental factors that modulate the risk and intensity of nerve damage. Currently, there are no effective treatments or prevention methods for CIPN, and symptom management is mostly symptomatic and palliative. Therefore, there is a high demand for better understanding of the cellular and molecular mechanisms involved in CIPN, as well as the development of new biomarkers and therapeutic targets. This review gives an overview of the current knowledge and challenges in the field of CIPN, focusing on the biological and molecular mechanisms underlying this disorder.
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Affiliation(s)
| | | | - Michele d’Angelo
- Department of Life, Health and Environmental Sciences, University of L’Aquila, 67100 L’Aquila, Italy; (H.K.); (A.C.); (V.C.)
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3
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Smith PA. The Known Biology of Neuropathic Pain and Its Relevance to Pain Management. Can J Neurol Sci 2024; 51:32-39. [PMID: 36799022 DOI: 10.1017/cjn.2023.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Patients with neuropathic pain are heterogeneous in pathophysiology, etiology, and clinical presentation. Signs and symptoms are determined by the nature of the injury and factors such as genetics, sex, prior injury, age, culture, and environment. Basic science has provided general information about pain etiology by studying the consequences of peripheral injury in rodent models. This is associated with the release of inflammatory cytokines, chemokines, and growth factors that sensitize sensory nerve endings, alter gene expression, promote post-translational modification of proteins, and alter ion channel function. This leads to spontaneous activity in primary afferent neurons that is crucial for the onset and persistence of pain and the release of secondary mediators such as colony-stimulating factor 1 from primary afferent terminals. These promote the release of tertiary mediators such as brain-derived neurotrophic factor and interleukin-1β from microglia and astrocytes. Tertiary mediators facilitate the transmission of nociceptive information at the spinal, thalamic, and cortical levels. For the most part, these findings have failed to identify new therapeutic approaches. More recent basic science has better mirrored the clinical situation by addressing the pathophysiology associated with specific types of injury, refinement of methodology, and attention to various contributory factors such as sex. Improved quantification of sensory profiles in each patient and their distribution into defined clusters may improve translation between basic science and clinical practice. If such quantification can be traced back to cellular and molecular aspects of pathophysiology, this may lead to personalized medicine approaches that dictate a rational therapeutic approach for each individual.
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Affiliation(s)
- Peter A Smith
- Neuroscience and Mental Health Institute and Department of Pharmacology, University of Alberta, Edmonton, Canada
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4
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Sas D, Gaudel F, Verdier D, Kolta A. Hyperexcitability of muscle spindle afferents in jaw-closing muscles in experimental myalgia: Evidence for large primary afferents involvement in chronic pain. Exp Physiol 2024; 109:100-111. [PMID: 38103003 PMCID: PMC10988680 DOI: 10.1113/ep090769] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023]
Abstract
The goals of this review are to improve understanding of the aetiology of chronic muscle pain and identify new targets for treatments. Muscle pain is usually associated with trigger points in syndromes such as fibromyalgia and myofascial syndrome, and with small spots associated with spontaneous electrical activity that seems to emanate from fibers inside muscle spindles in EMG studies. These observations, added to the reports that large-diameter primary afferents, such as those innervating muscle spindles, become hyperexcitable and develop spontaneous ectopic firing in conditions leading to neuropathic pain, suggest that changes in excitability of these afferents might make an important contribution to the development of pathological pain. Here, we review evidence that the muscle spindle afferents (MSAs) of the jaw-closing muscles become hyperexcitable in a model of chronic orofacial myalgia. In these afferents, as in other large-diameter primary afferents in dorsal root ganglia, firing emerges from fast membrane potential oscillations that are supported by a persistent sodium current (INaP ) mediated by Na+ channels containing the α-subunit NaV 1.6. The current flowing through NaV 1.6 channels increases when the extracellular Ca2+ concentration decreases, and studies have shown that INaP -driven firing is increased by S100β, an astrocytic protein that chelates Ca2+ when released in the extracellular space. We review evidence of how astrocytes, which are known to be activated in pain conditions, might, through their regulation of extracellular Ca2+ , contribute to the generation of ectopic firing in MSAs. To explain how ectopic firing in MSAs might cause pain, we review evidence supporting the hypothesis that cross-talk between proprioceptive and nociceptive pathways might occur in the periphery, within the spindle capsule.
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Affiliation(s)
- Dar'ya Sas
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
| | - Fanny Gaudel
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
| | - Dorly Verdier
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
| | - Arlette Kolta
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
- Faculté de Médecine DentaireUniversité de MontréalMontréalQuébecCanada
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5
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Vasylyev DV, Liu S, Waxman SG. I h current stabilizes excitability in rodent DRG neurons and reverses hyperexcitability in a nociceptive neuron model of inherited neuropathic pain. J Physiol 2023; 601:5341-5366. [PMID: 37846879 PMCID: PMC10843455 DOI: 10.1113/jp284999] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 09/25/2023] [Indexed: 10/18/2023] Open
Abstract
We show here that hyperpolarization-activated current (Ih ) unexpectedly acts to inhibit the activity of dorsal root ganglion (DRG) neurons expressing WT Nav1.7, the largest inward current and primary driver of DRG neuronal firing, and hyperexcitable DRG neurons expressing a gain-of-function Nav1.7 mutation that causes inherited erythromelalgia (IEM), a human genetic model of neuropathic pain. In this study we created a kinetic model of Ih and used it, in combination with dynamic-clamp, to study Ih function in DRG neurons. We show, for the first time, that Ih increases rheobase and reduces the firing probability in small DRG neurons, and demonstrate that the amplitude of subthreshold oscillations is reduced by Ih . Our results show that Ih , due to slow gating, is not deactivated during action potentials (APs) and has a striking damping action, which reverses from depolarizing to hyperpolarizing, close to the threshold for AP generation. Moreover, we show that Ih reverses the hyperexcitability of DRG neurons expressing a gain-of-function Nav1.7 mutation that causes IEM. In the aggregate, our results show that Ih unexpectedly has strikingly different effects in DRG neurons as compared to previously- and well-studied cardiac cells. Within DRG neurons where Nav1.7 is present, Ih reduces depolarizing sodium current inflow due to enhancement of Nav1.7 channel fast inactivation and creates additional damping action by reversal of Ih direction from depolarizing to hyperpolarizing close to the threshold for AP generation. These actions of Ih limit the firing of DRG neurons expressing WT Nav1.7 and reverse the hyperexcitability of DRG neurons expressing a gain-of-function Nav1.7 mutation that causes IEM. KEY POINTS: Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, the molecular determinants of hyperpolarization-activated current (Ih ) have been characterized as a 'pain pacemaker', and thus considered to be a potential molecular target for pain therapeutics. Dorsal root ganglion (DRG) neurons express Nav1.7, a channel that is not present in central neurons or cardiac tissue. Gain-of-function mutations (GOF) of Nav1.7 identified in inherited erythromelalgia (IEM), a human genetic model of neuropathic pain, produce DRG neuron hyperexcitability, which in turn produces severe pain. We found that Ih increases rheobase and reduces firing probability in small DRG neurons expressing WT Nav1.7, and demonstrate that the amplitude of subthreshold oscillations is reduced by Ih . We also demonstrate that Ih reverses the hyperexcitability of DRG neurons expressing a GOF Nav1.7 mutation (L858H) that causes IEM. Our results show that, in contrast to cardiac cells and CNS neurons, Ih acts to stabilize DRG neuron excitability and prevents excessive firing.
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Affiliation(s)
- Dmytro V. Vasylyev
- Department of Neurology and Center for Neuroscience & Regeneration Research, Yale University School of Medicine, New Haven, CT 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT 06516
| | - Shujun Liu
- Department of Neurology and Center for Neuroscience & Regeneration Research, Yale University School of Medicine, New Haven, CT 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT 06516
| | - Stephen G. Waxman
- Department of Neurology and Center for Neuroscience & Regeneration Research, Yale University School of Medicine, New Haven, CT 06510
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT 06516
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Cathenaut L, Schlichter R, Hugel S. Short-term plasticity in the spinal nociceptive system. Pain 2023; 164:2411-2424. [PMID: 37578501 DOI: 10.1097/j.pain.0000000000002999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 06/08/2023] [Indexed: 08/15/2023]
Abstract
ABSTRACT Somatosensory information is delivered to neuronal networks of the dorsal horn (DH) of the spinal cord by the axons of primary afferent neurons that encode the intensity of peripheral sensory stimuli under the form of a code based on the frequency of action potential firing. The efficient processing of these messages within the DH involves frequency-tuned synapses, a phenomenon linked to their ability to display activity-dependent forms of short-term plasticity (STP). By affecting differently excitatory and inhibitory synaptic transmissions, these STP properties allow a powerful gain control in DH neuronal networks that may be critical for the integration of nociceptive messages before they are forwarded to the brain, where they may be ultimately interpreted as pain. Moreover, these STPs can be finely modulated by endogenous signaling molecules, such as neurosteroids, adenosine, or GABA. The STP properties of DH inhibitory synapses might also, at least in part, participate in the pain-relieving effect of nonpharmacological analgesic procedures, such as transcutaneous electrical nerve stimulation, electroacupuncture, or spinal cord stimulation. The properties of target-specific STP at inhibitory DH synapses and their possible contribution to electrical stimulation-induced reduction of hyperalgesic and allodynic states in chronic pain will be reviewed and discussed.
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Affiliation(s)
- Lou Cathenaut
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
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Zhang Y, Gong H, Wang JS, Li MN, Cao DL, Gu J, Zhao LX, Zhang XD, Deng YT, Dong FL, Gao YJ, Sun WX, Jiang BC. Nerve Injury-Induced γH2AX Reduction in Primary Sensory Neurons Is Involved in Neuropathic Pain Processing. Int J Mol Sci 2023; 24:10148. [PMID: 37373296 DOI: 10.3390/ijms241210148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/02/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Phosphorylation of the serine 139 of the histone variant H2AX (γH2AX) is a DNA damage marker that regulates DNA damage response and various diseases. However, whether γH2AX is involved in neuropathic pain is still unclear. We found the expression of γH2AX and H2AX decreased in mice dorsal root ganglion (DRG) after spared nerve injury (SNI). Ataxia telangiectasia mutated (ATM), which promotes γH2AX, was also down-regulated in DRG after peripheral nerve injury. ATM inhibitor KU55933 decreased the level of γH2AX in ND7/23 cells. The intrathecal injection of KU55933 down-regulated DRG γH2AX expression and significantly induced mechanical allodynia and thermal hyperalgesia in a dose-dependent manner. The inhibition of ATM by siRNA could also decrease the pain threshold. The inhibition of dephosphorylation of γH2AX by protein phosphatase 2A (PP2A) siRNA partially suppressed the down-regulation of γH2AX after SNI and relieved pain behavior. Further exploration of the mechanism revealed that inhibiting ATM by KU55933 up-regulated extracellular-signal regulated kinase (ERK) phosphorylation and down-regulated potassium ion channel genes, such as potassium voltage-gated channel subfamily Q member 2 (Kcnq2) and potassium voltage-gated channel subfamily D member 2 (Kcnd2) in vivo, and KU559333 enhanced sensory neuron excitability in vitro. These preliminary findings imply that the down-regulation of γH2AX may contribute to neuropathic pain.
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Affiliation(s)
- Yan Zhang
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Hao Gong
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Ji-Shuai Wang
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Meng-Na Li
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - De-Li Cao
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Jun Gu
- Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Coral Gables, FL 33136, USA
| | - Lin-Xia Zhao
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Xin-Dan Zhang
- The 1st Clinical Department, China Medical University, Shenyang 110122, China
| | - Yu-Tao Deng
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Fu-Lu Dong
- Department of Pathology, Medical School, Nantong University, Nantong 226001, China
| | - Yong-Jing Gao
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Wen-Xing Sun
- Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong 226019, China
| | - Bao-Chun Jiang
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
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8
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Yao J, Novosel M, Bellampalli S, Kapo J, Joseph J, Prsic E. Lung Cancer Supportive Care and Symptom Management. Hematol Oncol Clin North Am 2023; 37:609-622. [PMID: 37024385 DOI: 10.1016/j.hoc.2023.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Lung cancer carries significant mortality and morbidity. In addition to treatment advances, supportive care may provide significant benefit for patients and their caregivers. A multidisciplinary approach is critical in addressing complications of lung cancer, including disease- and treatment-related complications, oncologic emergencies, symptom management and supportive care, and addressing the psychosocial needs of affected patients.
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Affiliation(s)
- Johnathan Yao
- Yale Internal Medicine-Traditional Residency Program, Department of Internal Medicine, Yale School of Medicine, Yale University, 333 Cedar Street, PO Box 208030, New Haven, CT 06520-8030, USA
| | - Madison Novosel
- Chronic Disease Epidemiology, Yale School of Public Health, Yale University, 60 College Street, New Haven, CT 06510, USA
| | - Shreya Bellampalli
- Medical Scientist Training Program, Mayo Clinic Alix School of Medicine, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Jennifer Kapo
- Department of General Internal Medicine, Yale School of Medicine, Yale University, 333 Cedar Street, PO Box 208025, New Haven, CT 06520, USA
| | - Julia Joseph
- Yale Internal Medicine-Traditional Residency Program, Department of Internal Medicine, Yale School of Medicine, Yale University, 333 Cedar Street, PO Box 208030, New Haven, CT 06520-8030, USA
| | - Elizabeth Prsic
- Section of Medical Oncology, Department of Medicine, Yale School of Medicine, Yale University, 333 Cedar Street, PO Box 208028, New Haven, CT 06520, USA.
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Raman S, Ikutame D, Okura K, Matsuka Y. Targeted Therapy for Orofacial Pain: A Novel Perspective for Precision Medicine. J Pers Med 2023; 13:jpm13030565. [PMID: 36983746 PMCID: PMC10057163 DOI: 10.3390/jpm13030565] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Orofacial pain (OFP) is a dental specialty that includes the diagnosis, management and treatment of disorders of the jaw, mouth, face, head and neck. Evidence-based understanding is critical in effectively treating OFPs as the pathophysiology of these conditions is multifactorial. Since OFP impacts the quality of life of the affected individuals, treating patients successfully is of the utmost significance. Despite the therapeutic choices available, treating OFP is still quite challenging, owing to inter-patient variations. The emerging trends in precision medicine could probably lead us to a paradigm shift in effectively managing the untreatable long-standing pain conditions. Precision medicine is designed based on the patient's genetic profile to meet their needs. Several significant relationships have been discovered based on the genetics and genomics of pain in the past, and some of the notable targets are discussed in this review. The scope of this review is to discuss preclinical and clinical trials that include approaches used in targeted therapy for orofacial pain. Future developments in pain medicine should benefit from current trends in research into novel therapeutic approaches.
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Affiliation(s)
- Swarnalakshmi Raman
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8504, Japan
| | - Daisuke Ikutame
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8504, Japan
| | - Kazuo Okura
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8504, Japan
| | - Yoshizo Matsuka
- Department of Stomatognathic Function and Occlusal Reconstruction, Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8504, Japan
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10
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Han G, Han Y, Yu L, Zhao Y, Yu Z. Patterns and Trends in Pharmacological Treatment for Outpatients with Postherpetic Neuralgia in Six Major Areas of China, 2015-2019. Healthcare (Basel) 2023; 11. [PMID: 36900769 DOI: 10.3390/healthcare11050764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/23/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
The aim of this study was to assess the patterns and trends of pharmacological treatment for outpatients with postherpetic neuralgia (PHN) in China in the period 2015-2019. Prescription data for outpatients with PHN were extracted from the database of the Hospital Prescription Analysis Program of China according to the inclusion criteria. The trends in yearly prescriptions and corresponding costs were analyzed and stratified by drug class and specific drugs. A total of 19,196 prescriptions from 49 hospitals in 6 major regions of China were included for analysis. The yearly prescriptions increased from 2534 in 2015 to 5676 in 2019 (p = 0.027), and the corresponding expenditures increased from CNY 898,618 in 2015 to CNY 2,466,238 in 2019 (p = 0.027). Gabapentin and pregabalin are the most commonly used drugs for PHN, and more than 30% of these two drugs were combined with mecobalamin. Opioids were the second most frequently prescribed drug class, and oxycodone accounted for the largest share of the cost. Topical drugs and TCAs are rarely used. The frequent use of pregabalin and gabapentin was in accordance with current guidelines; however, the use of oxycodone raised concerns about rationality and economic burden. The results of this study may benefit the allocation of medical resources and management for PHN in China and other countries.
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11
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Shiers S, Funk G, Cervantes A, Horton P, Dussor G, Hennen S, Price TJ. Na V1.7 mRNA and protein expression in putative projection neurons of the human spinal dorsal horn. bioRxiv 2023:2023.02.04.527110. [PMID: 36778234 PMCID: PMC9915702 DOI: 10.1101/2023.02.04.527110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
NaV1.7, a membrane-bound voltage-gated sodium channel, is preferentially expressed along primary sensory neurons, including their peripheral & central nerve endings, axons, and soma within the dorsal root ganglia and plays an integral role in amplifying membrane depolarization and pain neurotransmission. Loss- and gain-of-function mutations in the gene encoding NaV1.7, SCN9A, are associated with a complete loss of pain sensation or exacerbated pain in humans, respectively. As an enticing pain target supported by human genetic validation, many compounds have been developed to inhibit NaV1.7 but have disappointed in clinical trials. The underlying reasons are still unclear, but recent reports suggest that inhibiting NaV1.7 in central terminals of nociceptor afferents is critical for achieving pain relief by pharmacological inhibition of NaV1.7. We report for the first time that NaV1.7 mRNA is expressed in putative projection neurons (NK1R+) in the human spinal dorsal horn, predominantly in lamina 1 and 2, as well as in deep dorsal horn neurons and motor neurons in the ventral horn. NaV1.7 protein was found in the central axons of sensory neurons terminating in lamina 1-2, but also was detected in the axon initial segment of resident spinal dorsal horn neurons and in axons entering the anterior commissure. Given that projection neurons are critical for conveying nociceptive information from the dorsal horn to the brain, these data support that dorsal horn NaV1.7 expression may play an unappreciated role in pain phenotypes observed in humans with genetic SCN9A mutations, and in achieving analgesic efficacy in clinical trials.
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Affiliation(s)
- Stephanie Shiers
- University of Texas at Dallas, School of Behavioral and Brain Sciences and Center for Advanced Pain Studies
| | | | | | | | - Gregory Dussor
- University of Texas at Dallas, School of Behavioral and Brain Sciences and Center for Advanced Pain Studies
| | | | - Theodore J. Price
- University of Texas at Dallas, School of Behavioral and Brain Sciences and Center for Advanced Pain Studies
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