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Abstract
In recent years, there has been a substantial increase in the development of antitussive therapies and the first new therapy, gefapixant has been licenced in Europe. This review describes current unlicenced treatments for chronic cough and details treatments currently in development for refractory chronic cough and cough in idiopathic pulmonary fibrosis, as well as compounds previously explored.
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Affiliation(s)
- Jaclyn A Smith
- Division of Immunology, Immunity to Infection and Respiratory Medicine, University of Manchester and Manchester Academic Health Science Centre, Wythenshawe Hospital, Southmoor Road, Manchester, M23 9LT, UK.
- Manchester University NHS Foundation Trust, Manchester, UK.
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2
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Yi B, Wang S, Li W, Xu X, Yu L. Potential applications of P2X3 receptor antagonists in the treatment of refractory cough. Respir Med 2023; 217:107336. [PMID: 37364722 DOI: 10.1016/j.rmed.2023.107336] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 05/24/2023] [Accepted: 06/20/2023] [Indexed: 06/28/2023]
Abstract
Refractory chronic cough is defined as a clinical condition in which the cause of the cough remains unclear after comprehensive examination and treatment, or the cause is clear but symptomatic treatment is ineffective. Patients with refractory chronic cough experience a variety of physiological and psychological issues that significantly lower their quality of life and place a significant socio-economic burden on society. As a result, research both domestically and internationally has turned heavily toward these patients. Recently, several studies have identified P2X3 receptor antagonists for the treatment of refractory chronic cough, and this paper reviews the background, mechanism of action, evidence-based proof and application prospects of this class of drugs. KEY MESSAGE: There were plenty of studies about P2X3 receptor antagonists in the past, and in recent years this series of drugs are effective in refractory chronic cough. Although review articles summarizing have been published previously, most have focused on their chemical properties rather than their clinical aspects, with some omitting drugs that have been in clinical studies for nearly two years such as Eliapixant and Sivopixant. Focusing on four P2X3 receptor antagonists with proven efficacy in clinical studies, we analyzed the characteristics and disadvantages of each drug by comparing their clinical results of them and theoretically explained the common side effects of these drugs, as well as their potential for treating refractory chronic cough. This article can be used as a reference for the follow-up studies of P2X3 receptor antagonists in chronic cough. Additionally, it also has implications for the clinical focus of the drug and the approaches to relieve some side effects.
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Affiliation(s)
- Baiyi Yi
- Department of Pulmonary and Critical Care Medicine, Tongji Hospital, School of Medicine, Tongji University, No. 389 Xincun Road, Shanghai, 200065, China
| | - Shengyuan Wang
- Department of Pulmonary and Critical Care Medicine, Tongji Hospital, School of Medicine, Tongji University, No. 389 Xincun Road, Shanghai, 200065, China
| | - Wanzhen Li
- Department of Pulmonary and Critical Care Medicine, Tongji Hospital, School of Medicine, Tongji University, No. 389 Xincun Road, Shanghai, 200065, China
| | - Xianghuai Xu
- Department of Pulmonary and Critical Care Medicine, Tongji Hospital, School of Medicine, Tongji University, No. 389 Xincun Road, Shanghai, 200065, China.
| | - Li Yu
- Department of Pulmonary and Critical Care Medicine, Tongji Hospital, School of Medicine, Tongji University, No. 389 Xincun Road, Shanghai, 200065, China.
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Brister D, Wahab M, Rashad M, Diab N, Kolb M, Satia I. Emerging drugs in the treatment of chronic cough. Expert Opin Emerg Drugs 2023:1-11. [PMID: 37060576 DOI: 10.1080/14728214.2023.2203912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
INTRODUCTION Chronic cough is a debilitating condition that is among the most common reasons for seeking medical attention yet remains challenging to manage. Identifying an underlying respiratory, nasal or upper gastrointestinal disease triggering cough is the first step in assessment, but once this has been ruled out or adequately treated, many patients remain troubled with chronic cough. AREAS COVERED This narrative review discusses the role of existing treatments and describes the current research landscape for the development of new therapies for chronic cough greater than 8 weeks that is refractory (RCC) or unexplained (UCC). The literature search includes published studies found on pubmed and conference abstracts until 2023. EXPERT OPINION RCC/UCC can occur due to neuronal dysregulation of the vagus nerve or central nervous system. Hence, novel anti-tussives have targeted ion channels involved in the neuronal signaling which triggers cough. Although some therapies targeting receptors such as TRPV1 have failed to show efficacy, P2X3 antagonists have emerged as the most promising therapy for patients impacted by chronic cough. Disease specific therapies such as for idiopathic pulmonary fibrosis are in early development.
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Affiliation(s)
- Danica Brister
- McMaster University Department of Medicine, Hamilton, Canada
| | - Mustafaa Wahab
- McMaster University Department of Medicine, Hamilton, Canada
| | - Moaaz Rashad
- McMaster University Department of Medicine, Hamilton, Canada
| | - Nermin Diab
- McMaster University Department of Medicine, Hamilton, Canada
| | - Martin Kolb
- McMaster University Department of Medicine, Hamilton, Canada
- Firestone Institute for Respiratory Health, St Joseph's Healthcare, Hamilton, Canada
| | - Imran Satia
- McMaster University Department of Medicine, Hamilton, Canada
- Firestone Institute for Respiratory Health, St Joseph's Healthcare, Hamilton, Canada
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4
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Chung KF, McGarvey L, Song WJ, Chang AB, Lai K, Canning BJ, Birring SS, Smith JA, Mazzone SB. Cough hypersensitivity and chronic cough. Nat Rev Dis Primers 2022; 8:45. [PMID: 35773287 PMCID: PMC9244241 DOI: 10.1038/s41572-022-00370-w] [Citation(s) in RCA: 81] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/19/2022] [Indexed: 12/13/2022]
Abstract
Chronic cough is globally prevalent across all age groups. This disorder is challenging to treat because many pulmonary and extrapulmonary conditions can present with chronic cough, and cough can also be present without any identifiable underlying cause or be refractory to therapies that improve associated conditions. Most patients with chronic cough have cough hypersensitivity, which is characterized by increased neural responsivity to a range of stimuli that affect the airways and lungs, and other tissues innervated by common nerve supplies. Cough hypersensitivity presents as excessive coughing often in response to relatively innocuous stimuli, causing significant psychophysical morbidity and affecting patients' quality of life. Understanding of the mechanisms that contribute to cough hypersensitivity and excessive coughing in different patient populations and across the lifespan is advancing and has contributed to the development of new therapies for chronic cough in adults. Owing to differences in the pathology, the organs involved and individual patient factors, treatment of chronic cough is progressing towards a personalized approach, and, in the future, novel ways to endotype patients with cough may prove valuable in management.
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Affiliation(s)
- Kian Fan Chung
- Experimental Studies Unit, National Heart & Lung Institute, Imperial College London, London, UK
- Department of Respiratory Medicine, Royal Brompton and Harefield Hospital, London, UK
| | - Lorcan McGarvey
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Woo-Jung Song
- Department of Allergy and Clinical Immunology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - Anne B Chang
- Australian Centre for Health Services Innovation, Queensland's University of Technology and Department of Respiratory and Sleep Medicine, Queensland Children's Hospital, Brisbane, Queensland, Australia
- Division of Child Health, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Kefang Lai
- The First Affiliated Hospital of Guangzhou Medical University, National Center of Respiratory Medicine, National Clinical Research Center for Respiratory Disease, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, Guangzhou, China
| | | | - Surinder S Birring
- Centre for Human & Applied Physiological Sciences, School of Basic & Medical Biosciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - Jaclyn A Smith
- Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Stuart B Mazzone
- Department of Anatomy and Physiology, University of Melbourne, Victoria, Australia.
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Abdulqawi R, Satia I, Holt KJ, Dockry R, Sen S, Smith JA. An open-label study of the tolerability and potential efficacy of memantine for treating refractory chronic cough. ERJ Open Res 2021; 7:00447-2021. [PMID: 34549048 PMCID: PMC8450582 DOI: 10.1183/23120541.00447-2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 11/25/2022] Open
Abstract
Refractory chronic cough (RCC) is defined as cough lasting longer than 8 weeks either in the absence of an identifiable underlying cause or that remains resistant to treating any potential underlying causes [1]. Affected patients have a poor quality of life and suffer from fatigue, disturbed sleep, incontinence, frustration, anxiety, and depression [2]. Despite being a debilitating condition, no licensed treatment is available. Blocking NMDA receptors with memantine in refractory chronic cough patients is poorly tolerated and demonstrates no improvement in coughhttps://bit.ly/3kgx2g1
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Affiliation(s)
- Rayid Abdulqawi
- University of Manchester, Division of Infection, Immunity and Respiratory Medicine, and Manchester Academic Health Science Centre, Manchester, UK.,King Fahad Specialist Hospital-Dammam, and Dept of Medicine, Alfaisal University, Riyadh, Saudi Arabia.,Manchester University NHS Foundation Trust, Manchester, UK.,These authors contributed equally
| | - Imran Satia
- University of Manchester, Division of Infection, Immunity and Respiratory Medicine, and Manchester Academic Health Science Centre, Manchester, UK.,McMaster University, Dept of Medicine, Division of Respirology, Hamilton, Canada.,Firestone Institute for Respiratory Health, St Joseph's Healthcare, Hamilton, Canada.,These authors contributed equally
| | - Kimberley J Holt
- University of Manchester, Division of Infection, Immunity and Respiratory Medicine, and Manchester Academic Health Science Centre, Manchester, UK.,Manchester University NHS Foundation Trust, Manchester, UK
| | - Rachel Dockry
- University of Manchester, Division of Infection, Immunity and Respiratory Medicine, and Manchester Academic Health Science Centre, Manchester, UK.,Manchester University NHS Foundation Trust, Manchester, UK
| | - Shilpi Sen
- Manchester University NHS Foundation Trust, Manchester, UK
| | - Jaclyn A Smith
- University of Manchester, Division of Infection, Immunity and Respiratory Medicine, and Manchester Academic Health Science Centre, Manchester, UK.,Manchester University NHS Foundation Trust, Manchester, UK
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Yu L, Tsuji K, Ujihara I, Liu Q, Pavelkova N, Tsujimura T, Inoue M, Meeker S, Nisenbaum E, McDermott JS, Krajewski J, Undem BJ, Kollarik M, Canning BJ. Antitussive effects of Na V 1.7 blockade in Guinea pigs. Eur J Pharmacol 2021; 907:174192. [PMID: 34010618 DOI: 10.1016/j.ejphar.2021.174192] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 05/07/2021] [Accepted: 05/12/2021] [Indexed: 01/25/2023]
Abstract
Our previous studies implicated the voltage-gated sodium channel subtype NaV 1.7 in the transmission of action potentials by the vagal afferent nerves regulating cough and thus identified this channel as a rational therapeutic target for antitussive therapy. But it is presently unclear whether a systemically administered small molecule inhibitor of NaV 1.7 conductance can achieve therapeutic benefit in the absence of side effects on cardiovascular function, gastrointestinal motility or respiration. To this end, we have evaluated the antitussive effects of the NaV 1.7 selective blocker Compound 801 administered systemically in awake guinea pigs or administered topically in anesthetized guinea pigs. We also evaluated the antitussive effects of ambroxol, a low affinity NaV blocker modestly selective for tetrodotoxin resistant NaV subtypes. Both Compound 801 and ambroxol dose-dependently inhibited action potential conduction in guinea pig vagus nerves (assessed by compound potential), with ambroxol nearly 100-fold less potent than the NaV 1.7 selective Compound 801 in this and other NaV 1.7-dependent guinea pig and human tissue-based assays. Both drugs also inhibited citric acid evoked coughing in awake or anesthetized guinea pigs, with potencies supportive of an NaV 1.7-dependent mechanism. Notably, however, the antitussive effects of systemically administered Compound 801 were accompanied by hypotension and respiratory depression. Given the antitussive effects of topically administered Compound 801, we speculate that the likely insurmountable side effects on blood pressure and respiratory drive associated with systemic dosing make topical formulations a viable and perhaps unavoidable therapeutic strategy for targeting NaV 1.7 in cough.
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Affiliation(s)
- Li Yu
- Department of Pulmonary and Critical Care Medicine, Tongji Hospital, Tongii University School of Medicine, Shanghai, 200065, China
| | - Kojun Tsuji
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Izumi Ujihara
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Qi Liu
- Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD, 21224, USA
| | - Nikoleta Pavelkova
- Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Takanori Tsujimura
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Makoto Inoue
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Sonya Meeker
- Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD, 21224, USA
| | - Eric Nisenbaum
- Lilly Research Laboratories, Indianapolis, IN, 46285, USA
| | | | - Jeff Krajewski
- Lilly Research Laboratories, Indianapolis, IN, 46285, USA
| | - Bradley J Undem
- Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD, 21224, USA
| | - Marian Kollarik
- Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Brendan J Canning
- Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD, 21224, USA.
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Ni K, Guo J, Bu B, Pan Y, Li J, Liu L, Luo M, Deng L. Naringin as a plant-derived bitter tastant promotes proliferation of cultured human airway epithelial cells via activation of TAS2R signaling. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2021; 84:153491. [PMID: 33601237 DOI: 10.1016/j.phymed.2021.153491] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 01/29/2021] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Bitter tastants can activate bitter taste receptors (TAS2Rs) and thus initiate relaxation of airway smooth muscle cells (ASMCs), which have great potential in the development of novel bronchodilator drugs for asthma therapy. However, the canonical bitter substance, denatonium is known to induce apoptosis of airway epithelial cells (AECs), indicating that other bitter tastants may also impair the epithelial integrity to prevent hazardous particulate matters such as coronaviruses. Therefore, any bitter tastants intended for treating airway disease should be carefully evaluated for potential toxicity to AECs. HYPOTHESIS/PURPOSE Considering the vast diversity of bitter tastants in nature and different types of TAS2Rs expressed in airway cells, we hypothesized that there must be some natural bitter tastants to be not only potent in inducing relaxation of ASMCs but also unharmful to AECs. STUDY DESIGN AND METHODS Here we evaluated a group of bitter flavonoids that are derived from fruits and commonly used in traditional herbal medicine, including apigenin, hesperetin, kaempferol, naringenin, quercetin, and naringin, for their effects on the proliferation of human airway epithelial-like (16HBE14o-, BEAS-2B, and A549) cells cultured in vitro. Cell proliferation and associated signaling pathways were assessed by cell counting, ATP assay, cell cycling assay, quantitative RT-PCR, Fluo-4 labeling, and fluorescence resonance energy transfer, respectively. RESULTS The results show that five of the six tested bitter tastants inhibited, but only naringin promoted the proliferation of the 16HBE14o-, BEAS-2B, and A549 cells at the dose of a few hundred micromoles. Furthermore, the naringin-promoted proliferation of the 16HBE14o- cells was associated with enhanced cell cycle progression, mRNA expression of cyclin E, and evoked calcium signaling/ERK signaling, which were all attenuated by inhibition of the TAS2R signaling pathways with specific blockers. CONCLUSION These findings indicate that although the majority of the bitter flavonoids may inhibit the proliferation of AECs, naringin emerged as one to promote the proliferation of AECs via cell cycle progression and TAS2R-activated intracellular signaling. It suggests that naringin and not a few other bitter tastants can be proven with nontoxicity to the airway epithelial structure and function, which provides further confidence in the development of safe and effective TAS2R-based bronchodilators for asthma therapy.
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Affiliation(s)
- Kai Ni
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, China
| | - Jia Guo
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, China
| | - Bing Bu
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, China
| | - Yan Pan
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, China
| | - Jingjing Li
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, China
| | - Lei Liu
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, China
| | - Mingzhi Luo
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, China.
| | - Linhong Deng
- Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, Jiangsu, China.
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Olsen WL, Rose M, Golder FJ, Wang C, Hammond JC, Bolser DC. Intra-Arterial, but Not Intrathecal, Baclofen and Codeine Attenuates Cough in the Cat. Front Physiol 2021; 12:640682. [PMID: 33746778 PMCID: PMC7973226 DOI: 10.3389/fphys.2021.640682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 02/15/2021] [Indexed: 11/15/2022] Open
Abstract
Centrally-acting antitussive drugs are thought to act solely in the brainstem. However, the role of the spinal cord in the mechanism of action of these drugs is unknown. The purpose of this study was to determine if antitussive drugs act in the spinal cord to reduce the magnitude of tracheobronchial (TB) cough-related expiratory activity. Experiments were conducted in anesthetized, spontaneously breathing cats (n = 22). Electromyograms (EMG) were recorded from the parasternal (PS) and transversus abdominis (TA) or rectus abdominis muscles. Mechanical stimulation of the trachea or larynx was used to elicit TB cough. Baclofen (10 and 100 μg/kg, GABA-B receptor agonist) or codeine (30 μg/kg, opioid receptor agonist) was administered into the intrathecal (i.t.) space and also into brainstem circulation via the vertebral artery. Cumulative doses of i.t. baclofen or codeine had no effect on PS, abdominal muscle EMGs or cough number during the TB cough. Subsequent intra-arterial (i.a.) administration of baclofen or codeine significantly reduced magnitude of abdominal and PS muscles during TB cough. Furthermore, TB cough number was significantly suppressed by i.a. baclofen. The influence of these drugs on other behaviors that activate abdominal motor pathways was also assessed. The abdominal EMG response to noxious pinch of the tail was suppressed by i.t. baclofen, suggesting that the doses of baclofen that were employed were sufficient to affect spinal pathways. However, the abdominal EMG response to expiratory threshold loading was unaffected by i.t. administration of either baclofen or codeine. These results indicate that neither baclofen nor codeine suppress cough via a spinal action and support the concept that the antitussive effect of these drugs is restricted to the brainstem.
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Mazzone SB, McGarvey L. Mechanisms and Rationale for Targeted Therapies in Refractory and Unexplained Chronic Cough. Clin Pharmacol Ther 2020; 109:619-636. [PMID: 32748976 PMCID: PMC7983941 DOI: 10.1002/cpt.2003] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/24/2020] [Indexed: 12/22/2022]
Abstract
Chronic cough, defined as a cough lasting > 8 weeks, is a common medical condition that exerts a substantial physical, mental, and social burden on patients. A subset of patients with chronic cough are troubled with a cough that persists despite optimal treatment of presumed associated common and uncommon conditions (refractory chronic cough; RCC) or in which no diagnosable cause for cough can be identified despite extensive assessment (unexplained chronic cough; UCC). Many of these patients exhibit clinical features of cough hypersensitivity, including laryngeal paresthesia, hypertussia, and allotussia. Over-the-counter cough remedies are ineffective and can lead to intolerable side effects when used for RCC/UCC, and the lack of approved treatments indicated for these conditions reflects a major unmet need. An increased understanding of the anatomy and neurophysiology of protective and pathologic cough has fostered a robust clinical development pipeline of several targeted therapies for RCC/UCC. This manuscript reviews the mechanisms presumed to underly RCC/UCC together with the rationale and clinical evidence for several targeted therapies currently under clinical investigation, including transient receptor potential channel antagonists, P2X3-receptor antagonists, voltage-gated sodium channel blockers, neuromodulators, and neurokinin-1-receptor antagonists. Finally, we provide an overview of targets that have been investigated in preclinical models of cough and other airway diseases that may hold future promise for clinical studies in RCC/UCC. Development of targeted therapies with different sites of action may foster a precision medicine approach to treat this heterogeneous, underserved patient population.
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Affiliation(s)
- Stuart B Mazzone
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Lorcan McGarvey
- Wellcome-Wolfson Institute of Experimental Medicine, Queen's University Belfast, Belfast, UK
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Satia I, Nagashima A, Usmani OS. Exploring the role of nerves in asthma; insights from the study of cough. Biochem Pharmacol 2020; 179:113901. [PMID: 32156662 DOI: 10.1016/j.bcp.2020.113901] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/03/2020] [Indexed: 12/30/2022]
Abstract
Cough in asthma predicts disease severity, prognosis, and is a common and troublesome symptom. Cough is the archetypal airway neuronal reflex, yet little is understood about the underlying neuronal mechanisms. It is generally assumed that symptoms arise because of airway hyper-responsiveness and/or airway inflammation, but despite using inhaled corticosteroids and bronchodilators targeting these pathologies, a large proportion of patients have persistent coughing. This review focuses on the prevalence and impact of cough in asthma and explores data from pre-clinical and clinical studies which have explored neuronal mechanisms of cough and asthma. We present evidence to suggest patients with asthma have evidence of neuronal dysfunction, which is further heightened and exaggerated by both bronchoconstriction and airway eosinophilia. Identifying patients with excessive coughing with asthma may represent a neuro-phenotype and hence developing treatment for this symptom is important for reducing the burden of disease on patients' lives and currently represents a major unmet clinical need.
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Affiliation(s)
- I Satia
- McMaster University, Department of Medicine, Division of Respirology, Canada; Firestone Institute for Respiratory Health, St Joseph's Hospital, Canada; University of Manchester, Division of Infection, Immunity and Respiratory Medicine, and Manchester Academic Health Science Centre, Manchester, United Kingdom.
| | - A Nagashima
- McMaster University, Department of Medicine, Division of Respirology, Canada
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12
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El‐Hashim AZ, Mathews S, Al‐Shamlan F. Central adenosine A 1 receptors inhibit cough via suppression of excitatory glutamatergic and tachykininergic neurotransmission. Br J Pharmacol 2018; 175:3162-3174. [PMID: 29767468 PMCID: PMC6031887 DOI: 10.1111/bph.14360] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/02/2018] [Accepted: 04/10/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE The adenosine A1 receptor is reported to mediate several excitatory effects in the airways and has inhibitory effects in the CNS. In this study, we investigated the role of peripheral and central A1 receptors in regulating cough and airway obstruction. EXPERIMENTAL APPROACH Drugs were administered to guinea pigs via inhalation or i.c.v. infusion. Following the administration of different drugs, cough was induced by exposing guinea pigs to aerosolized 0.4 M citric acid. An automated analyser recorded both cough and airway obstruction simultaneously using whole-body plethysmography. KEY RESULTS The A1 receptor agonist, cyclopentyladenosine (CPA, administered by inhalation), dose-dependently inhibited cough and also inhibited airway obstruction. Similarly, CPA, administered i.c.v., inhibited both the citric acid-induced cough and airway obstruction; this was prevented by pretreatment with the A1 receptor antagonist DPCPX (i.c.v.). Treatment with DPCPX alone dose-dependently enhanced the citric acid-induced cough and airway obstruction. This effect was reversed following treatment with either the glutamate GluN1 receptor antagonist D-AP5 or the neurokinin NK1 receptor antagonist FK-888. CONCLUSIONS AND IMPLICATIONS These findings suggest that activation of either peripheral or central adenosine A1 receptors inhibits citric acid-induced cough and airway obstruction. The data also suggest that tonic activation of central adenosine A1 receptors serves as a negative regulator of cough and airway obstruction, secondary to inhibition of excitatory glutamatergic and tachykininergic neurotransmission.
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Affiliation(s)
- Ahmed Z El‐Hashim
- Department of Pharmacology and Therapeutics, Faculty of PharmacyKuwait UniversityKuwait
| | - Seena Mathews
- Department of Pharmacology and Therapeutics, Faculty of PharmacyKuwait UniversityKuwait
| | - Fajer Al‐Shamlan
- Department of Pharmacology and Therapeutics, Faculty of PharmacyKuwait UniversityKuwait
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Ryan NM, Vertigan AE, Birring SS. An update and systematic review on drug therapies for the treatment of refractory chronic cough. Expert Opin Pharmacother 2018; 19:687-711. [PMID: 29658795 PMCID: PMC5935050 DOI: 10.1080/14656566.2018.1462795] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 04/05/2018] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Chronic Cough (CC) is common and often associated with significant comorbidity and decreased quality of life. In up to 50% of cases, the cough is refractory despite extensive investigation and treatment trials. It is likely that the key abnormality in refractory CC is dysfunctional, hypersensitive sensory nerves, similar to conditions such as laryngeal hypersensitivity and neuropathic pain. AREAS COVERED The aim of this systematic review is to assess drug therapies for refractory CC. The authors review the current management of CC and provide discussion of the similarities between neuropathic pain and refractory CC. They review repurposed and new pharmacological treatments. Several meta-analyses were performed to compare the efficacy of treatments where possible. EXPERT OPINION Repurposed pain medications such as gabapentin and pregabalin reduce the frequency of cough and improve quality of life. Along with speech pathology, they are important and alternate treatments for refractory CC. However, more treatments are needed and the P2X3 ion channel receptor antagonists show the most promise. With a better understanding of neuronal activation and sensitisation and their signal processing in the brain, improved animal models of cough, and the use of validated cough measurement tools, more effective treatments will develop.
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Affiliation(s)
- Nicole M. Ryan
- Clinical Toxicology Research Group, School of Medicine and Public Health, The University of Newcastle, Calvary Mater Hospital, Newcastle, Australia
| | - Anne E. Vertigan
- Centre for Asthma and Respiratory Diseases, School of Medicine and Public Health, Hunter Medical Research Institute, The University of Newcastle, Newcastle, Australia
- Department of Speech Pathology, John Hunter Hospital, Hunter New England Health, Newcastle, Australia
| | - Surinder S. Birring
- Division of Asthma, Allergy & Lung Biology, School of Transplantation, Immunology, Infection & Inflammation Sciences, Faculty of Life Sciences & Medicine, King’s College London, London, UK
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Chou YL, Mori N, Canning BJ. Opposing effects of bronchopulmonary C-fiber subtypes on cough in guinea pigs. Am J Physiol Regul Integr Comp Physiol 2017; 314:R489-R498. [PMID: 29187382 DOI: 10.1152/ajpregu.00313.2017] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We have addressed the hypothesis that the opposing effects of bronchopulmonary C-fiber activation on cough are attributable to the activation of C-fiber subtypes. Coughing was evoked in anesthetized guinea pigs by citric acid (0.001-2 M) applied topically in 100-µl aliquots to the tracheal mucosa. In control preparations, citric acid evoked 10 ± 1 coughs cumulatively. Selective activation of the pulmonary C fibers arising from the nodose ganglia with either aerosols or continuous intravenous infusion of adenosine or the 5-HT3 receptor-selective agonist 2-methyl-5-HT nearly abolished coughing evoked subsequently by topical citric acid challenge. Delivering adenosine or 2-methyl-5-HT directly to the tracheal mucosa (where few if any nodose C fibers terminate) was without effect on citric acid-evoked cough. These actions of pulmonary administration of adenosine and 2-methyl-5-HT were accompanied by an increase in respiratory rate, but it is unlikely that the change in respiratory pattern caused the decrease in coughing, as the rapidly adapting receptor stimulant histamine also produced a marked tachypnea but was without effect on cough. In awake guinea pigs, adenosine failed to evoke coughing but reduced coughing induced by the nonselective C-fiber stimulant capsaicin. We conclude that bronchopulmonary C-fiber subtypes in guinea pigs have opposing effects on cough, with airway C fibers arising from the jugular ganglia initiating and/or sensitizing the cough reflex and the intrapulmonary C fibers arising from the nodose ganglia actively inhibiting cough upon activation.
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Affiliation(s)
- Yang-Ling Chou
- Johns Hopkins Asthma and Allergy Center , Baltimore, Maryland
| | - Nanako Mori
- Johns Hopkins Asthma and Allergy Center , Baltimore, Maryland
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Viral laryngitis: a mimic and a monster - range, presentation, management. Curr Opin Otolaryngol Head Neck Surg 2016; 23:454-8. [PMID: 26397458 DOI: 10.1097/moo.0000000000000203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
PURPOSE OF REVIEW The purpose of this review is to highlight recent literature relating to the diagnosis and treatment of some less common forms of viral laryngitis. The main conditions addressed in this review are chronic cough or postviral vagal neuropathy, varicella zoster infection of the larynx, and a condition increasingly suspected as being virally induced, idiopathic ulcerative laryngitis. RECENT FINDINGS Diagnosis of these conditions requires a thorough history and physical exam, and in certain cases referral to other subspecialties such as gastroenterology and pulmonology. Chronic cough due to postviral vagal neuropathy is a diagnosis of exclusion; however, recent literature does suggest that certain studies such as laryngeal electromyography can be of use in reaching a diagnosis. Treatment of this neuropathy has focused on use of neuromodulators. Treatment of laryngeal shingles and idiopathic ulcerative laryngitis has not been well defined because of the rarity of these conditions. SUMMARY Recent studies regarding these conditions and potential future treatment options will be discussed.
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Hewitt MM, Adams G, Mazzone SB, Mori N, Yu L, Canning BJ. Pharmacology of Bradykinin-Evoked Coughing in Guinea Pigs. J Pharmacol Exp Ther 2016; 357:620-8. [PMID: 27000801 PMCID: PMC4885511 DOI: 10.1124/jpet.115.230383] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 03/18/2016] [Indexed: 12/20/2022] Open
Abstract
Bradykinin has been implicated as a mediator of the acute pathophysiological and inflammatory consequences of respiratory tract infections and in exacerbations of chronic diseases such as asthma. Bradykinin may also be a trigger for the coughing associated with these and other conditions. We have thus set out to evaluate the pharmacology of bradykinin-evoked coughing in guinea pigs. When inhaled, bradykinin induced paroxysmal coughing that was abolished by the bradykinin B2 receptor antagonist HOE 140. These cough responses rapidly desensitized, consistent with reports of B2 receptor desensitization. Bradykinin-evoked cough was potentiated by inhibition of both neutral endopeptidase and angiotensin-converting enzyme (with thiorphan and captopril, respectively), but was largely unaffected by muscarinic or thromboxane receptor blockade (atropine and ICI 192605), cyclooxygenase, or nitric oxide synthase inhibition (meclofenamic acid and N(G)-nitro-L-arginine). Calcium influx studies in bronchopulmonary vagal afferent neurons dissociated from vagal sensory ganglia indicated that the tachykinin-containing C-fibers arising from the jugular ganglia mediate bradykinin-evoked coughing. Also implicating the jugular C-fibers was the observation that simultaneous blockade of neurokinin2 (NK2; SR48968) and NK3 (SR142801 or SB223412) receptors nearly abolished the bradykinin-evoked cough responses. The data suggest that bradykinin induces coughing in guinea pigs by activating B2 receptors on bronchopulmonary C-fibers. We speculate that therapeutics targeting the actions of bradykinin may prove useful in the treatment of cough.
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Affiliation(s)
- Matthew M Hewitt
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (G.A., N.M., B.J.C.); University of Pennsylvania, Philadelphia, Pennsylvania (M.M.H.); University of Queensland, Australia (S.B.M.); and Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China (L.Y.)
| | - Gregory Adams
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (G.A., N.M., B.J.C.); University of Pennsylvania, Philadelphia, Pennsylvania (M.M.H.); University of Queensland, Australia (S.B.M.); and Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China (L.Y.)
| | - Stuart B Mazzone
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (G.A., N.M., B.J.C.); University of Pennsylvania, Philadelphia, Pennsylvania (M.M.H.); University of Queensland, Australia (S.B.M.); and Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China (L.Y.)
| | - Nanako Mori
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (G.A., N.M., B.J.C.); University of Pennsylvania, Philadelphia, Pennsylvania (M.M.H.); University of Queensland, Australia (S.B.M.); and Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China (L.Y.)
| | - Li Yu
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (G.A., N.M., B.J.C.); University of Pennsylvania, Philadelphia, Pennsylvania (M.M.H.); University of Queensland, Australia (S.B.M.); and Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China (L.Y.)
| | - Brendan J Canning
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (G.A., N.M., B.J.C.); University of Pennsylvania, Philadelphia, Pennsylvania (M.M.H.); University of Queensland, Australia (S.B.M.); and Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China (L.Y.)
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17
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Taylor-Clark TE. Role of reactive oxygen species and TRP channels in the cough reflex. Cell Calcium 2016; 60:155-62. [PMID: 27016063 DOI: 10.1016/j.ceca.2016.03.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 03/09/2016] [Accepted: 03/10/2016] [Indexed: 12/15/2022]
Abstract
The cough reflex is evoked by noxious stimuli in the airways. Although this reflex is essential for health, it can be triggered chronically in inflammatory and infectious airway disease. Neuronal transient receptor potential (TRP) channels such as ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) are polymodal receptors expressed on airway nociceptive afferent nerves. Reactive oxygen species (ROS) and other reactive compounds are associated with inflammation, from either NADPH oxidase or mitochondria. These reactive compounds cause activation and hyperexcitability of nociceptive afferents innervating the airways, and evidence suggests key contributions of TRPA1 and TRPV1.
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Affiliation(s)
- Thomas E Taylor-Clark
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA.
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18
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Chung KF, Canning B, McGarvey L. Eight International London Cough Symposium 2014: Cough hypersensitivity syndrome as the basis for chronic cough. Pulm Pharmacol Ther 2015; 35:76-80. [PMID: 26341666 DOI: 10.1016/j.pupt.2015.08.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 08/31/2015] [Indexed: 02/01/2023]
Abstract
At the Eighth International London Cough Conference held in London in July 2014, the focus was on the relatively novel concept of cough hypersensitivity syndrome (CHS) as forming the basis of chronic cough. This concept has been formulated following understanding of the neuronal pathways for cough and a realisation that not all chronic cough is usually associated with a cause. The CHS is defined by troublesome coughing triggered by low level of thermal, mechanical or chemical exposure. It also encompasses other symptoms or sensations such as laryngeal hypersensitivity, nasal hypersensitivity and possibly also symptoms related to gastrooesopahgeal reflux. The pathophysiologic basis of the CHS is now being increasingly linked to an enhancement of the afferent pathways of the cough reflex both at the peripheral and central levels. Mechanisms involved include the interactions of inflammatory mechanisms with cough sensors in the upper airways and with neuronal pathways of cough, associated with a central component. Tools for assessing CHS in the clinic need to be developed. New drugs may be developed to control CHS. A roadmap is suggested from the inception of the CHS concept towards the development of newer antitussives at the Symposium.
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Affiliation(s)
- Kian Fan Chung
- Experimental Studies, National Heart and Lung Institute, Imperial College London, UK; Royal Brompton NIHR Biomedical Research Unit, London, UK.
| | - Brendan Canning
- The Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224, USA
| | - Lorcan McGarvey
- Department of Respiratory Medicine, Centre for Infection and Immunity, Queen's University Belfast, UK
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19
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NMDA and GABA receptors as potential targets in cough hypersensitivity syndrome. Curr Opin Pharmacol 2015; 22:29-36. [DOI: 10.1016/j.coph.2015.03.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 03/02/2015] [Accepted: 03/02/2015] [Indexed: 12/21/2022]
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20
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Dicpinigaitis PV, Canning BJ, Garner R, Paterson B. Effect of memantine on cough reflex sensitivity: translational studies in guinea pigs and humans. J Pharmacol Exp Ther 2015; 352:448-54. [PMID: 25525191 PMCID: PMC11047062 DOI: 10.1124/jpet.114.221218] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 12/15/2014] [Indexed: 01/24/2023] Open
Abstract
Cough is the most common complaint for which outpatients in the United States seek medical attention, and yet available therapeutic options for cough lack proven efficacy and are further limited by safety and abuse liabilities. Thus, safe and effective cough suppressants are needed. Recent preclinical studies described the antitussive effects of memantine, an N-methyl-d-aspartate receptor channel blocker used in the treatment of Alzheimer's disease. The goals of the present study were to compare the antitussive effects of memantine, dextromethorphan, and codeine in guinea pigs; to relate the dose-dependent actions of memantine in these studies to peak plasma concentrations achieved following oral administration; and to provide the first ever evaluation of the antitussive effect of memantine in humans. In guinea pigs, memantine and codeine were comparable in efficacy and potency but both were superior to dextromethorphan in the citric acid cough challenge model. The pharmacokinetic analyses suggest that memantine was active in guinea pigs at micromolar plasma concentrations. Subsequently, 14 healthy volunteers as well as 14 otherwise healthy adults with acute viral upper respiratory tract infection (URI) underwent capsaicin cough challenges 6 hours after ingestion of 20 mg memantine and matched placebo in a randomized, double-blind, crossover fashion. In healthy volunteers, memantine significantly inhibited cough reflex sensitivity (P = 0.034). In subjects with URI, responsiveness to capsaicin was markedly increased, and in these patients, the inhibition of cough reflex sensitivity by memantine relative to placebo did not reach statistical significance (P = 0.088). These data support further research to investigate the potential of memantine as a clinically useful antitussive.
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Affiliation(s)
- Peter V Dicpinigaitis
- Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York (P.V.D.); Johns Hopkins School of Medicine, Baltimore, Maryland (B.J.C.); and Cerecor, Inc., Baltimore, Maryland (R.G., B.P.)
| | - Brendan J Canning
- Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York (P.V.D.); Johns Hopkins School of Medicine, Baltimore, Maryland (B.J.C.); and Cerecor, Inc., Baltimore, Maryland (R.G., B.P.)
| | - Rachel Garner
- Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York (P.V.D.); Johns Hopkins School of Medicine, Baltimore, Maryland (B.J.C.); and Cerecor, Inc., Baltimore, Maryland (R.G., B.P.)
| | - Blake Paterson
- Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York (P.V.D.); Johns Hopkins School of Medicine, Baltimore, Maryland (B.J.C.); and Cerecor, Inc., Baltimore, Maryland (R.G., B.P.)
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21
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Peripheral neural circuitry in cough. Curr Opin Pharmacol 2015; 22:9-17. [PMID: 25704498 DOI: 10.1016/j.coph.2015.02.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/02/2015] [Accepted: 02/04/2015] [Indexed: 01/22/2023]
Abstract
Cough is a reflex that serves to protect the airways. Excessive or chronic coughing is a major health issue that is poorly controlled by current therapeutics. Significant effort has been made to understand the mechanisms underlying the cough reflex. The focus of this review is the evidence supporting the role of specific airway sensory nerve (afferent) populations in the initiation and modulation of the cough reflex in health and disease.
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22
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Bonvini SJ, Birrell MA, Smith JA, Belvisi MG. Targeting TRP channels for chronic cough: from bench to bedside. Naunyn Schmiedebergs Arch Pharmacol 2015; 388:401-20. [PMID: 25572384 DOI: 10.1007/s00210-014-1082-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/16/2014] [Indexed: 12/24/2022]
Abstract
Cough is currently the most common reason for patients to visit a primary care physician in the UK, yet it remains an unmet medical need. Current therapies have limited efficacy or have potentially dangerous side effects. Under normal circumstances, cough is a protective reflex to clear the lungs of harmful particles; however, in disease, cough can become excessive, dramatically impacting patients' lives. In many cases, this condition is linked to inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD), but can also be refractory to treatment and idiopathic in nature. Therefore, there is an urgent need to develop therapies, and targeting the sensory afferent arm of the reflex which initiates the cough reflex may uncover novel therapeutic targets. The cough reflex is initiated following activation of ion channels present on vagal sensory afferents. These ion channels include the transient receptor potential (TRP) family of cation-selective ion channels which act as cellular sensors and respond to changes in the external environment. Many direct activators of TRP channels, including arachidonic acid derivatives, a lowered airway pH, changes in temperature, and altered airway osmolarity are present in the diseased airway where responses to challenge agents which activate airway sensory nerve activity are known to be enhanced. Furthermore, the expression of some TRP channels is increased in airway disease. Together, this makes them promising targets for the treatment of chronic cough. This review will cover the current understanding of the role of the TRP family of ion channels in the activation of airway sensory nerves and cough, focusing on four members, transient receptor potential vanilloid (TRPV) 1, transient receptor potential ankyrin (TRPA) 1, TRPV4, and transient receptor potential melastatin (TRPM) 8 as these represent the channels where most information has been gathered with relevance to the airways. We will describe recent data and highlight the possible therapeutic utility of specific TRP channel antagonists as antitussives in the clinic.
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Affiliation(s)
- Sara J Bonvini
- Respiratory Pharmacology Group, Airway Disease Section, National Heart & Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
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23
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McGovern AE, Mazzone SB. Guinea pig models of asthma. CURRENT PROTOCOLS IN PHARMACOLOGY 2014; 67:5.26.1-5.26.38. [PMID: 25446291 DOI: 10.1002/0471141755.ph0526s67] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Described in this unit are methods for establishing guinea pig models of asthma. Sufficient detail is provided to enable investigators to study bronchoconstriction, cough, airway hyperresponsiveness, inflammation, and remodeling.
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Affiliation(s)
- Alice E McGovern
- School of Biomedical Sciences, University of Queensland, St Lucia, Australia
| | - Stuart B Mazzone
- School of Biomedical Sciences, University of Queensland, St Lucia, Australia
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24
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McGarvey L. Update: the search for the human cough receptor. Lung 2014; 192:459-65. [PMID: 24770379 DOI: 10.1007/s00408-014-9581-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 03/29/2014] [Indexed: 10/25/2022]
Abstract
Despite the best efforts of basic and applied science, the identity of the human "cough receptor" remains elusive. The attraction of identifying a single "catch all" cough receptor is obvious, although such an objective is unlikely to be realised given the concept of "cough hypersensitivity," which is now considered the most clinically relevant description of what underlies problem coughing. One means of progressing this area is to join the thinking and experimental effort of basic science and clinical research in an effective manner. Some of the best examples of cooperative and translational research over the years together with an update on the most recent work will be discussed in this article.
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Affiliation(s)
- Lorcan McGarvey
- Centre for Infection and Immunity, Queens University Belfast, Health Sciences Building, Lisburn Road, Belfast, BT9 7BL, Northern Ireland,
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25
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Dicpinigaitis PV, Morice AH, Birring SS, McGarvey L, Smith JA, Canning BJ, Page CP. Antitussive drugs--past, present, and future. Pharmacol Rev 2014; 66:468-512. [PMID: 24671376 PMCID: PMC11060423 DOI: 10.1124/pr.111.005116] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Cough remains a serious unmet clinical problem, both as a symptom of a range of other conditions such as asthma, chronic obstructive pulmonary disease, gastroesophageal reflux, and as a problem in its own right in patients with chronic cough of unknown origin. This article reviews our current understanding of the pathogenesis of cough and the hypertussive state characterizing a number of diseases as well as reviewing the evidence for the different classes of antitussive drug currently in clinical use. For completeness, the review also discusses a number of major drug classes often clinically used to treat cough but that are not generally classified as antitussive drugs. We also reviewed a number of drug classes in various stages of development as antitussive drugs. Perhaps surprising for drugs used to treat such a common symptom, there is a paucity of well-controlled clinical studies documenting evidence for the use of many of the drug classes in use today, particularly those available over the counter. Nonetheless, there has been a considerable increase in our understanding of the cough reflex over the last decade that has led to a number of promising new targets for antitussive drugs being identified and thus giving some hope of new drugs being available in the not too distant future for the treatment of this often debilitating symptom.
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Affiliation(s)
- P V Dicpinigaitis
- King's College London, Franklin Wilkins Building, 100 Stamford St., London, SE1 9NH, UK.
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Hilton ECY, Baverel PG, Woodcock A, Van Der Graaf PH, Smith JA. Pharmacodynamic modeling of cough responses to capsaicin inhalation calls into question the utility of the C5 end point. J Allergy Clin Immunol 2013; 132:847-55.e1-5. [PMID: 23777849 DOI: 10.1016/j.jaci.2013.04.042] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 03/26/2013] [Accepted: 04/18/2013] [Indexed: 11/16/2022]
Abstract
BACKGROUND Inhaled capsaicin elicits cough reproducibly in human subjects and is widely used in the study of cough and antitussive therapies. However, the traditional end points C2 and C5 (the concentrations of capsaicin inducing at least 2 or 5 coughs, respectively) display extensive overlap between health and disease and therefore might not best reflect clinically relevant mechanisms. OBJECTIVES We sought to investigate capsaicin dose responses in different disease groups. METHODS Two novel capsaicin cough challenges were compared in patients with chronic cough (CC; n = 20), asthmatic patients (n = 18), and healthy volunteers (HVs; n = 20). Increasing doubling doses of capsaicin (0.48-1000 μmol/L, 4 inhalations per dose) were administered in challenge 1, whereas the order of the doses was randomized in challenge 2. A nonlinear mixed-effects model compared dose-response parameters by disease group and sex. Parameters were also correlated with objective cough frequency. RESULTS The model classified subjects based on maximum cough response evoked by any concentration of capsaicin (Emax) and the capsaicin dose inducing half-maximal response (ED50). HVs and asthmatic patients were not statistically different for either parameter and therefore combined for analysis (mean ED50, 38.6 μmol/L [relative SE, 28%]; mean Emax, 4.5 coughs [relative SE, 11%]). Compared with HVs/asthmatic patients, patients with CC had lower ED50 values (14.7 μmol/L [relative SE, 28%], P = .008) and higher Emax values (8.6 coughs [relative SE, 11%], P < .0001). Emax values highly correlated with 24-hour cough frequency (r = 0.71, P < .001) and were 37% higher in female compared with male subjects, regardless of disease group (P < .001). CONCLUSIONS Nonlinear mixed-effects modeling demonstrates that maximal capsaicin cough responses better discriminate health from disease and predict spontaneous cough frequency and therefore provide important insights into the mechanisms underlying CC.
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Affiliation(s)
- Emma C Y Hilton
- Respiratory Research Group, University of Manchester, Manchester, United Kingdom
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Smith JA, Houghton LA. The oesophagus and cough: laryngo-pharyngeal reflux, microaspiration and vagal reflexes. COUGH 2013; 9:12. [PMID: 23590893 PMCID: PMC3640905 DOI: 10.1186/1745-9974-9-12] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 03/17/2013] [Indexed: 12/25/2022]
Abstract
Gastro-oesophageal reflux disease is generally considered to be one of the commonest causes of chronic cough, however randomised controlled trials of proton pump inhibitors have often failed to support this notion. This article reviews the most recent studies investigating the mechanisms thought to link reflux and cough, namely laryngo-pharyngeal reflux, micro-aspiration and neuronal cross-organ sensitisation. How recent evidence might shed light on the failure of acid suppressing therapies and suggest new approaches to treating reflux related cough are also discussed.
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Affiliation(s)
- Jaclyn A Smith
- Respiratory and Allergy Centre, The University of Manchester, University Hospital of South Manchester, Manchester, UK.
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Canning BJ, Mori N, Lehmann A. Antitussive effects of the peripherally restricted GABAB receptor agonist lesogaberan in guinea pigs: comparison to baclofen and other GABAB receptor-selective agonists. COUGH 2012; 8:7. [PMID: 23025757 PMCID: PMC3520872 DOI: 10.1186/1745-9974-8-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 09/07/2012] [Indexed: 12/17/2022]
Abstract
UNLABELLED BACKGROUND Gastroesophageal reflux disease (GERD) is a common cause of chronic cough. Both acid and nonacid reflux is thought to play a role in the initiation of coughing and cough hypersensitivity. The GABAB receptor agonist lesogaberan was developed as a peripherally restricted anti-reflux therapy that reduces the frequency of transient lower esophageal sphincter relaxations (TLESR; the major cause of reflux) in animals and in patients with GERD. GABAB receptor agonists have also been shown to possess antitussive effects in patients and in animals independent of their effects on TLESR, suggesting that lesogaberan may be a promising treatment for chronic cough. METHODS We have assessed the direct antitussive effects of lesogaberan (AZD3355). The effects of other GABAB receptor agonists were also determined. Coughing was evoked in awake guinea pigs using aerosol challenges with citric acid. RESULTS Lesogaberan dose-dependently inhibited citric acid evoked coughing in guinea pigs. Comparable effects of the GABAB receptor agonists baclofen and 3-aminopropylphosphinic acid (3-APPiA) on cough were also observed. Baclofen produced obvious signs of sedation and respiratory depression. By contrast, both lesogaberan and 3-APPiA (both inactivated centrally by GABA transporters) were devoid of sedative effects and did not alter respiratory rate. CONCLUSIONS Together, the data suggest that lesogaberan and related GABAB receptor agonists may hold promise as safe and effective antitussive agents largely devoid of CNS side effects.
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Affiliation(s)
- Brendan J Canning
- Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, Maryland, 21224, USA.
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