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Plevkova J, Brozmanova M, Matloobi A, Poliacek I, Honetschlager J, Buday T. Animal models of cough. Respir Physiol Neurobiol 2021; 290:103656. [PMID: 33781930 DOI: 10.1016/j.resp.2021.103656] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 03/16/2021] [Accepted: 03/21/2021] [Indexed: 01/10/2023]
Abstract
Cough is a vital airway reflex that keeps the respiratory tract wisely protected. It is also a sign of many diseases of the respiratory system and it may become a disease in its own right. Even though the efficacy of antitussive compounds is extensively studied in animal models with promising results, the treatment of pathological cough in humans is insufficient at the moment. The limited translational potential of animal models used to study cough causes, mechanisms and possible therapeutic targets stems from multiple sources. First of all, cough induced in the laboratory by mechanical or chemical stimuli is far from natural cough present in human disease. The main objective of this review is to provide a comprehensive summary of animal models currently used in cough research and to address their advantages and disadvantages. We also want to encourage cough researchers to call for precision is research by addressing the sex bias which has existed in basic cough research for decades and discuss the role of specific pathogen-free (SPF) animals.
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Affiliation(s)
- Jana Plevkova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Department of Pathophysiology, Martin, Slovakia
| | - Mariana Brozmanova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Department of Pathophysiology, Martin, Slovakia
| | - Alireza Matloobi
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Department of Pathophysiology, Martin, Slovakia
| | - Ivan Poliacek
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Department of Biophysics, Martin, Slovakia
| | - Jan Honetschlager
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Tomas Buday
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Department of Pathophysiology, Martin, Slovakia.
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Belvisi MG, Birrell MA, Khalid S, Wortley MA, Dockry R, Coote J, Holt K, Dubuis E, Kelsall A, Maher SA, Bonvini S, Woodcock A, Smith JA. Neurophenotypes in Airway Diseases. Insights from Translational Cough Studies. Am J Respir Crit Care Med 2017; 193:1364-72. [PMID: 26741046 DOI: 10.1164/rccm.201508-1602oc] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Most airway diseases, including chronic obstructive pulmonary disease (COPD), are associated with excessive coughing. The extent to which this may be a consequence of increased activation of vagal afferents by pathology in the airways (e.g., inflammatory mediators, excessive mucus) or an altered neuronal phenotype is unknown. Understanding whether respiratory diseases are associated with dysfunction of airway sensory nerves has the potential to identify novel therapeutic targets. OBJECTIVES To assess the changes in cough responses to a range of inhaled irritants in COPD and model these in animals to investigate the underlying mechanisms. METHODS Cough responses to inhaled stimuli in patients with COPD, healthy smokers, refractory chronic cough, asthma, and healthy volunteers were assessed and compared with vagus/airway nerve and cough responses in a cigarette smoke (CS) exposure guinea pig model. MEASUREMENTS AND MAIN RESULTS Patients with COPD had heightened cough responses to capsaicin but reduced responses to prostaglandin E2 compared with healthy volunteers. Furthermore, the different patient groups all exhibited different patterns of modulation of cough responses. Consistent with these findings, capsaicin caused a greater number of coughs in CS-exposed guinea pigs than in control animals; similar increased responses were observed in ex vivo vagus nerve and neuron cell bodies in the vagal ganglia. However, responses to prostaglandin E2 were decreased by CS exposure. CONCLUSIONS CS exposure is capable of inducing responses consistent with phenotypic switching in airway sensory nerves comparable with the cough responses observed in patients with COPD. Moreover, the differing profiles of cough responses support the concept of disease-specific neurophenotypes in airway disease. Clinical trial registered with www.clinicaltrials.gov (NCT 01297790).
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Affiliation(s)
- Maria G Belvisi
- 1 Respiratory Pharmacology Group, Division of Airway Disease, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Mark A Birrell
- 1 Respiratory Pharmacology Group, Division of Airway Disease, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Saifudin Khalid
- 2 Centre for Respiratory and Allergy, University of Manchester, University Hospital of South Manchester, Manchester Academic Health Sciences Centre, Manchester, United Kingdom; and
| | - Michael A Wortley
- 1 Respiratory Pharmacology Group, Division of Airway Disease, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Rachel Dockry
- 2 Centre for Respiratory and Allergy, University of Manchester, University Hospital of South Manchester, Manchester Academic Health Sciences Centre, Manchester, United Kingdom; and
| | - Julie Coote
- 1 Respiratory Pharmacology Group, Division of Airway Disease, National Heart and Lung Institute, Imperial College London, London, United Kingdom.,3 Respiratory Diseases, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts
| | - Kimberley Holt
- 2 Centre for Respiratory and Allergy, University of Manchester, University Hospital of South Manchester, Manchester Academic Health Sciences Centre, Manchester, United Kingdom; and
| | - Eric Dubuis
- 1 Respiratory Pharmacology Group, Division of Airway Disease, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Angela Kelsall
- 2 Centre for Respiratory and Allergy, University of Manchester, University Hospital of South Manchester, Manchester Academic Health Sciences Centre, Manchester, United Kingdom; and
| | - Sarah A Maher
- 1 Respiratory Pharmacology Group, Division of Airway Disease, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Sara Bonvini
- 1 Respiratory Pharmacology Group, Division of Airway Disease, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Ashley Woodcock
- 2 Centre for Respiratory and Allergy, University of Manchester, University Hospital of South Manchester, Manchester Academic Health Sciences Centre, Manchester, United Kingdom; and
| | - Jaclyn A Smith
- 2 Centre for Respiratory and Allergy, University of Manchester, University Hospital of South Manchester, Manchester Academic Health Sciences Centre, Manchester, United Kingdom; and
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El-Kady MM, Girgis ZI, Abd El-Rasheed EA, Shaker O, Attallah MI, Soliman AA. Role of selective blocking of bradykinin receptor subtypes in attenuating allergic airway inflammation in guinea pigs. Eur J Pharmacol 2016; 788:152-159. [PMID: 27321873 DOI: 10.1016/j.ejphar.2016.06.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 06/10/2016] [Accepted: 06/15/2016] [Indexed: 11/25/2022]
Abstract
The present study was designed to evaluate the potential role of bradykinin antagonists (R-715; bradykinin B1 receptor antagonist and icatibant; bradykinin B2 receptor antagonist) in treatment of allergic airway inflammation in comparison to dexamethasone and montelukast. R-715 as dexamethasone significantly decreased peribronchial leukocyte infiltration, bronchoalveolar lavage fluid (BALF) albumin and interleukin 1β as well as serum OVA-specific IgE level. Also, R-715 like montelukast significantly decreased BALF cell count (total and eosinophils). Icatibant showed negative results. The current findings suggest that selective bradykinin B1 receptor antagonists may have the therapeutic potential for the treatment of allergic airway inflammation.
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Affiliation(s)
- Mohamed M El-Kady
- Department of Medical Pharmacology, Faculty of Medicine, Cairo University, 11559, Egypt.
| | - Zarif I Girgis
- Department of Medical Pharmacology, Faculty of Medicine, Cairo University, 11559, Egypt.
| | - Eman A Abd El-Rasheed
- Department of Medical Pharmacology, Faculty of Medicine, Cairo University, 11559, Egypt.
| | - Olfat Shaker
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Cairo University, 11559, Egypt.
| | - Magdy I Attallah
- Department of Medical Pharmacology, Faculty of Medicine, Cairo University, 11559, Egypt.
| | - Ahmed A Soliman
- Department of Pathology, Faculty of Medicine, Cairo University, 11559, Egypt.
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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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Luo YL, Li PB, Zhang CC, Zheng YF, Wang S, Nie YC, Zhang KJ, Su WW. Effects of four antitussives on airway neurogenic inflammation in a guinea pig model of chronic cough induced by cigarette smoke exposure. Inflamm Res 2013; 62:1053-61. [PMID: 24085318 DOI: 10.1007/s00011-013-0664-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 08/27/2013] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE The effects of four antitussives, including codeine phosphate (CP), moguisteine, levodropropizine (LVDP) and naringin, on airway neurogenic inflammation and enhanced cough were investigated in guinea pig model of chronic cough. METHODS Guinea pigs were exposed to CS for 8 weeks. At the 7th and 8th week, the animals were treated with vehicle, CP (4.8 mg/kg), moguisteine (24 mg/kg), LVDP (14 mg/kg) and naringin (18.4 mg/kg) respectively. Then the cough and the time-enhanced pause area under the curve (Penh-AUC) during capsaicin challenge were recorded. The substance P (SP) content, NK-1 receptor expression and neutral endopeptidase (NEP) activity in lung were determined. RESULTS Chronic CS exposure induced a bi-phase time course of cough responsiveness to capsaicin. Eight weeks of CS exposure significantly enhanced the airway neurogenic inflammation and cough response in guinea pigs. Two weeks of treatment with CP, moguisteine, LVDP or naringin effectively attenuated the chronic CS-exposure enhanced cough. Only naringin exerted significant effect on inhibiting Penh-AUC, SP content and NK-1 receptor expression, as well as preventing the declining of NEP activity in lung. CONCLUSIONS Chronic CS-exposed guinea pig is suitable for studying chronic pathological cough, in which naringin is effective on inhibiting both airway neurogenic inflammation and enhanced cough.
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Affiliation(s)
- Yu-long Luo
- Key Laboratory of Gene Engineering of the Ministry of Education, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, No.135, Xingangxi Street, Guangzhou, 510275, People's Republic of China,
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Pavuluri S, Hanus V, Bergren DR. Interaction of tobacco smoke exposure and ovalbumin-sensitization promotes goblet cell and submucosal gland metaplasia in guinea pigs. Respir Physiol Neurobiol 2013; 189:639-45. [DOI: 10.1016/j.resp.2013.07.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/16/2013] [Accepted: 07/17/2013] [Indexed: 12/13/2022]
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Grace MS, Dubuis E, Birrell MA, Belvisi MG. Pre-clinical studies in cough research: role of Transient Receptor Potential (TRP) channels. Pulm Pharmacol Ther 2013; 26:498-507. [PMID: 23474212 PMCID: PMC3763377 DOI: 10.1016/j.pupt.2013.02.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 02/19/2013] [Accepted: 02/24/2013] [Indexed: 02/08/2023]
Abstract
Cough is a protective reflex and defence mechanism in healthy individuals, which helps clear excessive secretions and foreign material from the lungs. Cough often presents as the first and most persistent symptom of many respiratory diseases and some non-respiratory disorders, but can also be idiopathic, and is a common respiratory complaint for which medical attention is sought. Chronic cough of various aetiologies is a regular presentation to specialist respiratory clinics, and is reported as a troublesome symptom by a significant proportion of the population. Despite this, the treatment options for cough are limited. The lack of effective anti-tussives likely stems from our incomplete understanding of how the tussive reflex is mediated. However, research over the last decade has begun to shed some light on the mechanisms which provoke cough, and may ultimately provide us with better anti-tussive therapies. This review will focus on the in vitro and in vivo models that are currently used to further our understanding of the sensory innervation of the respiratory tract, and how these nerves are involved in controlling the cough response. Central to this are the Transient Receptor Potential (TRP) ion channels, a family of polymodal receptors that can be activated by such diverse stimuli as chemicals, temperature, osmotic stress, and mechanical perturbation. These ion channels are thought to be molecular pain integrators and targets for novel analgesic agents for the treatment of various pain disorders but some are also being developed as anti-tussives.
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Affiliation(s)
- Megan S Grace
- Respiratory Pharmacology, Pharmacology & Toxicology Section, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, Exhibition Road, London SW7 2AZ, UK
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8
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Kou YR, Kwong K, Lee LY. Airway inflammation and hypersensitivity induced by chronic smoking. Respir Physiol Neurobiol 2011; 178:395-405. [PMID: 21397052 DOI: 10.1016/j.resp.2011.03.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 03/01/2011] [Accepted: 03/01/2011] [Indexed: 12/23/2022]
Abstract
Airway hypersensitivity, characterized by enhanced excitability of airway sensory nerves, is a prominent pathophysiological feature in patients with airway inflammatory diseases. Although the underlying pathogenic mechanism is not fully understood, chronic airway inflammation is believed to be primarily responsible. Cigarette smoking is known to cause chronic airway inflammation, accompanied by airway hyperresponsiveness. Experimental evidence indicates that enhanced excitability of vagal bronchopulmonary sensory nerves and increased tachykinin synthesis in these nerves resulting from chronic inflammation are important contributing factors to the airway hyperresponsiveness. Multiple inflammatory mediators released from various types of structural and inflammatory cells are involved in the smoking-induced airway inflammation, which is mainly regulated by redox-sensitive signaling pathways and transcription factors. Furthermore, recent studies have reported potent sensitizing and stimulatory effects of these inflammatory mediators such as prostanoids and reactive oxygen species on these sensory nerves. In summary, these studies using cigarette smoking as an experimental approach have identified certain potentially important cell signaling pathways and underlying mechanisms of the airway hypersensitivity induced by chronic airway inflammation.
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Affiliation(s)
- Yu Ru Kou
- Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC
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Kanezaki M, Ebihara S, Nikkuni E, Gui P, Suda C, Ebihara T, Yamasaki M, Kohzuki M. Perception of urge-to-cough and dyspnea in healthy smokers with decreased cough reflex sensitivity. COUGH 2010; 6:1. [PMID: 20181097 PMCID: PMC2829486 DOI: 10.1186/1745-9974-6-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 02/05/2010] [Indexed: 01/29/2023]
Abstract
Background Although cigarette smoking has been implicated as an important risk factor for the development of respiratory symptoms, the perceptional aspects of two symptoms in smokers have not been fully elucidated. Therefore, we simultaneously evaluated the cough reflex sensitivity, the cognition of urge-to-cough and perception of dyspnea in both healthy smokers and non-smokers. Methods Fourteen male healthy never-smokers and 14 age-matched male healthy current-smokers were recruited via public postings. The cough reflex sensitivity and the urge-to-cough were evaluated by the inhalation of citric acid. The perception of dyspnea was evaluated by Borg scores during applications of external inspiratory resistive loads. Results The cough reflex threshold to citric acid, as expressed by the lowest concentration of citric acid that elicited two or more coughs (C2) and the lowest concentration of citric acid that elicited five or more coughs (C5) in smokers was significantly higher than in non-smokers. The urge-to-cough log-log slope in smokers was significantly milder than that of non-smokers. There were no significant differences in the urge-to-cough threshold between non-smokers and smokers. There were no significant differences in perceptions of dyspnea between non-smokers and smokers. Conclusions The study showed that decreased cough reflex sensitivity in healthy smokers was accompanied by a decreased cognition of urge-to-cough whereas it was not accompanied by the alternation of perception of dyspnea. Physicians should pay attention to the perceptual alterations of cough in smokers.
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Affiliation(s)
- Masashi Kanezaki
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Seiryo-machi 1-1, Aoba-ku, Sendai 980-8574, Japan
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Effect of smoking on cough reflex sensitivity: basic and preclinical studies. Lung 2009; 188 Suppl 1:S23-7. [PMID: 19844757 DOI: 10.1007/s00408-009-9191-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Accepted: 09/24/2009] [Indexed: 12/27/2022]
Abstract
In healthy nonsmokers, inhalation of one single puff of cigarette smoke immediately evoked airway irritation and cough, which were either prevented or markedly diminished after premedication with hexamethonium. Single-fiber recording experiments performed in anesthetized animals showed that both C fibers and rapidly adapting receptors in the lungs and airways were stimulated by inhalation of one breath of cigarette smoke. Application of nicotine evoked an inward current and triggered depolarization and action potentials in a concentration-dependent manner in a subset of isolated vagal pulmonary sensory neurons. Taken together, these studies showed that activation of the nicotinic acetylcholine receptors expressed on airway sensory nerves is mainly responsible for the acute airway irritation and cough reflex elicited by inhaled cigarette smoke. Chronic exposure to cigarette smoke consistently induces enhanced cough responses to various inhaled tussive agents in guinea pigs. The increased cough sensitivity involves primarily an elevated sensitivity of cough sensors and also an enhanced synaptic transmission of their afferent signals at the nucleus tractus solitaries. In contrast to the observations in animal studies, both enhanced and diminished cough sensitivities to tussive agents have been reported in chronic smokers. This discrepancy is probably related to the history of chronic smoking of the individual smokers and the severity of existing airway inflammation and dysfunction. Furthermore, several other factors possibly contributing to the regulation of cough receptor sensitivity in chronic smokers should also be considered.
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Modulation of sensory nerve function and the cough reflex: understanding disease pathogenesis. Pharmacol Ther 2009; 124:354-75. [PMID: 19818366 DOI: 10.1016/j.pharmthera.2009.09.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Accepted: 09/16/2009] [Indexed: 12/29/2022]
Abstract
To cough is a protective defence mechanism that is vital to remove foreign material and secretions from the airways and which in the normal state serves its function appropriately. Modulation of the cough reflex pathway in disease can lead to inappropriate chronic coughing and an augmented cough response. Chronic cough is a symptom that can present in conjunction with a number of diseases including chronic obstructive pulmonary disease (COPD) and asthma, although often the cause of chronic cough may be unknown. As current treatments for cough have proved to exhibit little efficacy and are largely ineffective, there is a need to develop novel, efficacious and safe antitussive therapies. The underlying mechanisms of the cough reflex are complex and involve a network of events, which are not fully understood. It is accepted that the cough reflex is initiated following activation of airway sensory nerves. Therefore, in the hope of identifying novel antitussives, much research has focused on understanding the neural mechanisms of cough provocation. Experimentally this has been undertaken using chemical or mechanical tussive stimuli in conjunction with animal models of cough and clinical cough assessments. This review will discuss the neural mechanisms involved in the cough, changes that occur under pathophysiological conditions and and how current research may lead to novel therapeutic opportunities for the treatment of cough.
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Chou YL, Scarupa MD, Mori N, Canning BJ. Differential effects of airway afferent nerve subtypes on cough and respiration in anesthetized guinea pigs. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1572-84. [PMID: 18768768 DOI: 10.1152/ajpregu.90382.2008] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The hypothesis that respiratory reflexes, such as cough, reflect the net and often opposing effects of activation of multiple afferent nerve subpopulations throughout the airways was evaluated. Laryngeal and tracheal mucosal challenge with either citric acid or mechanical probing reliably evoked coughing in anesthetized guinea pigs. No other stimulus reliably evoked coughing in these animals, regardless of route of administration and despite some profound effects on respiration. Selectively activating vagal C-fibers arising from the nodose ganglia with either adenosine or 2-methyl-5-HT evoked only tachypnea. Selectively activating vagal afferents arising from the jugular ganglia induced respiratory slowing and apnea. Nasal afferent nerve activation by capsaicin, citric acid, hypertonic saline, or histamine evoked only respiratory slowing. Histamine, which activates intrapulmonary rapidly adapting receptors but not airway or lung C-fibers or tracheal bronchial cough receptors induced bronchospasm and tachypnea, but no coughing. The results indicate that the reflexes initiated by stimuli thought to be selective for some afferent nerve subtypes will likely depend on the net and potentially opposing effects of multiple afferent nerve subpopulations throughout the airways. The data also provide further evidence that the afferent nerves regulating cough in anesthetized guinea pigs are distinct from either C-fibers or intrapulmonary rapidly adapting receptors.
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Affiliation(s)
- Yang-Ling Chou
- Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA
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Groneberg-Kloft B, Feleszko W, Dinh QT, van Mark A, Brinkmann E, Pleimes D, Fischer A. Analysis and evaluation of environmental tobacco smoke exposure as a risk factor for chronic cough. COUGH 2007; 3:6. [PMID: 17475014 PMCID: PMC1884172 DOI: 10.1186/1745-9974-3-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Accepted: 05/02/2007] [Indexed: 11/11/2022]
Abstract
Exposure to environmental tobacco smoke (ETS) and active tobacco smoking has been shown to increase symptoms of bronchial asthma such as bronchoconstriction but effects on other respiratory symptoms remain poorly assessed. Current levels of exposure to tobacco smoke may also be responsible for the development of chronic cough in both children and adults. The present study analyses the effects of tobacco smoke exposure as potential causes of chronic cough. A panel of PubMed-based searches was performed relating the symptom of cough to various forms of tobacco smoke exposure. It was found that especially prenatal and postnatal exposures to ETS have an important influence on children's respiratory health including the symptom of cough. These effects may be prevented if children and pregnant women are protected from exposure to ETS. Whereas the total number of studies adressing the relationship between cough and ETS exposure is relatively small, the present study demonstrated that there is a critical amout of data pointing to a causative role of environmental ETS exposure for the respiratory symptom of cough. Since research efforts have only targeted this effect to a minor extent, future epidemiological and experimental studies are needed to further unravel the relation between ETS and cough.
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Affiliation(s)
- Beatrix Groneberg-Kloft
- Division of Allergy Research, Charité – Universitätsmedizin Berlin, Free University and Humboldt-University, D-13353 Berlin, Germany
| | - Wojciech Feleszko
- Department of Pediatric Pneumology and Allergy, The Medical University Children's Hospital, PL-01-184 Warsaw, Poland
| | - Quoc Thai Dinh
- Department of Medicine, Charité – Universitätsmedizin Berlin, Free University and Humboldt-University, D-13353 Berlin, Germany
| | - Anke van Mark
- Institute of Occupational Medicine, University zu Lübeck, D-23538 Lübeck, Germany
| | - Elke Brinkmann
- Department of Prevention, Norddeutsche Metall-Berufsgenossenschaft, D-30173 Hannover, Germany
| | - Dirk Pleimes
- Division of Allergy Research, Charité – Universitätsmedizin Berlin, Free University and Humboldt-University, D-13353 Berlin, Germany
| | - Axel Fischer
- Division of Allergy Research, Charité – Universitätsmedizin Berlin, Free University and Humboldt-University, D-13353 Berlin, Germany
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Lewis CA, Ambrose C, Banner K, Battram C, Butler K, Giddings J, Mok J, Nasra J, Winny C, Poll C. Animal models of cough: literature review and presentation of a novel cigarette smoke-enhanced cough model in the guinea-pig. Pulm Pharmacol Ther 2006; 20:325-33. [PMID: 17240178 DOI: 10.1016/j.pupt.2006.12.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Accepted: 12/04/2006] [Indexed: 11/25/2022]
Abstract
A wealth of literature describes the approaches that investigators have used to develop animal models of cough. The relevance of the models to cough in man and disease is still unknown. Furthermore, the choice of animal model that is used will depend on the purpose of the investigation and what questions are being asked. Cigarette smoke is known to cause COPD and cough is a principle symptom where patients demonstrate an increased cough response to citric acid or capsaicin. This paper describes the development of exacerbated cough to these agents in the guinea-pig following cigarette smoke exposure and pharmacological profiling of these models. Male Dunkin-Hartley guinea-pigs were exposed to air or cigarette smoke (4 or 5 research cigarettes daily for the capsaicin and citric acid studies, respectively) for a 3 s puff every 30 s, for up to 10 days. At selected time points conscious, unrestrained animals were placed in a plethysmograph chamber and challenged with an aerosol of 0.3 M citric acid (10 min) or 10 microM capsaicin (7 min). Cough and Penh area under the curve (AUC) were recorded during the exposure and for a further 10 min (citric acid) or 8 min (capsaicin) after exposure. Compounds were administered on day 3 or 11 for citric acid or capsaicin, respectively. Significant enhancement of citric acid-induced cough was evident 24 h (12+/-2 to 24+/-4* coughs) after a single exposure and further enhanced after 2 days (13+/-3 to 36+/-4* coughs). Enhanced cough to capsaicin was not reliable until after 10 days of cigarette smoke exposure (2+/-1 to 14+/-3** coughs). Data are expressed as mean+/-s.e.mean (n=10), *p<0.05, **p<0.01 vs. air-exposed animals (Mann-Whitney rank-sum test). The minimum effective doses to inhibit citric acid-induced cough were 10, 10, 3 and 0.3 mg/kg for codeine (p.o. -30 min), a selective NK(1)/NK(2) antagonist, DNK333 (p.o. -2 h), terbutaline (s.c. -1 h) and atropine (s.c. -1 h), respectively. The minimum effective doses to inhibit capsaicin-induced cough were 3, 1, 0.3 and 0.3 mg/kg for codeine, DNK333, terbutaline (p.o. -2 h) and atropine, respectively. The VR1 antagonists capsazepine and iodo-resiniferatoxin (IRTX) did not inhibit cough in either model. Differences in sensitivity between citric acid and capsaicin to pharmacological agents may be partly explained by the difference in magnitude of response to these agents. Clinically used compounds such as codeine and terbutaline have shown activity in both models, however the relevance of the models to cough in man and disease for potential new therapies is unknown.
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Affiliation(s)
- C A Lewis
- Novartis Institute for BioMedical Research, Wimblehurst Road, Horsham, West Sussex, UK.
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15
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Park HK, Oh SY, Kim TB, Bahn JW, Shin ES, Lee JE, Oh HB, Kim YK, Park T, Cho SH, Min KU, Kim YY. Association of genetic variations in neurokinin-2 receptor with enhanced cough sensitivity to capsaicin in chronic cough. Thorax 2006; 61:1070-5. [PMID: 16893949 PMCID: PMC2117043 DOI: 10.1136/thx.2005.054429] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Chronic cough is associated with increased sensitivity to inhaled capsaicin, and both tachykinins and their receptors play important roles in the cough reflex. However, associations between polymorphisms of the tachykinin receptor genes and cough sensitivity in patients with non-productive chronic cough have not been reported. METHODS Direct sequencing was used to identify single nucleotide polymorphisms (SNPs) in the genes for the neurokinin-1 and neurokinin-2 receptors (NK-1R and NK-2R, respectively). Informative non-synonymous SNPs were scored using the single base extension method for 312 patients with chronic cough and for 100 age matched healthy controls. The cough response to capsaicin was recorded for 312 patients with chronic cough, and the potential genetic association between cough sensitivity to capsaicin and the NK-1R and NK-2R genotypes was evaluated. RESULTS Two informative SNPs were identified in NK-2R (Gly231Glu and Arg375His), whereas no informative SNP was found in NK-1R. After adjusting for atopy, sex, age, and smoking, the prevalence of enhanced cough sensitivity to capsaicin was higher in the chronic cough patients with the 231Glu allele (p = 0.004; OR 1.69 (95% CI 1.18 to 2.42)) and the 231Glu_375Arg haplotype (p = 0.003; OR 1.71 (95% CI 1.20 to 2.24)). Moreover, the lowest capsaicin concentration to cause five consecutive coughs (C5) was significantly lower in patients with 231Glu (mean (SD) 44.1 (53.2) v 60.9 (55.8) microM/l, p = 0.04) and those with 231Glu_375Arg (43.2 (52.7) v 69.6 (52.0) microM/l, p = 0.03). CONCLUSIONS The results of this study suggest that NK-2R gene polymorphisms are involved in the enhanced cough sensitivity to capsaicin of patients with chronic cough.
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Affiliation(s)
- H-K Park
- Department of Internal Medicine, Pusan National University College of Medicine, Busan, Korea
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16
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Carr MJ, Lee LY. Plasticity of peripheral mechanisms of cough. Respir Physiol Neurobiol 2006; 152:298-311. [PMID: 16338180 DOI: 10.1016/j.resp.2005.11.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 11/04/2005] [Accepted: 11/07/2005] [Indexed: 11/23/2022]
Abstract
The cough reflex pathway is characterized by a remarkable plasticity often resulting in a persistent and uncontrollable urge to cough during airway inflammation. In many instances cough becomes up regulated to the extent that ceases to fulfill its defensive role in protecting the airways. The exact mechanisms underlying this plasticity are unknown and likely involves a variety of factors influencing the function of the peripheral and central nervous system. This review outlines the evidence of increased cough sensitivity during airway disease. This is followed by a discussion of the peripheral mechanisms involved including the potential role of inflammatory mediators, neutrophins and changes in the airway mucosal structure. A greater understanding of the mechanisms leading to enhanced cough should lead to the development of more effective therapeutic strategies.
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Affiliation(s)
- Michael J Carr
- GlaxoSmithKline, 709 Swedeland Road, King of Prussia, PA 19406, UW 2531, USA.
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17
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Abstract
Enhanced coughing can be produced in a variety of animal models, including the guinea pig, cat, dog and pig. Typically, airway inflammation has been produced by sensitization, exposure to cigarette smoke, sulphur dioxide or angiotensin-converting enzyme inhibitors. In some of these models, inflammatory mediators such as bradykinin and tachykinins have been shown to contribute to the enhanced coughing. While most of these studies have focussed on peripheral mechanisms, increases in central excitability of the cough reflex have been shown to occur as a result of airway inflammation. As such, we propose that enhanced coughing in pathological conditions is the result of plastic changes in both peripheral and central neural elements. Furthermore, we present a modified model of the neurogenesis of cough that takes into account peripheral and central plasticity induced by mediators of inflammation.
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Affiliation(s)
- Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, P.O. Box 100144, Gainesville, FL 32610-0144, USA.
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18
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19
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Bergren DR, Rendell MS. Depressed ventilatory reflexes after capsaicin challenge in streptozotocin-treated rats. Life Sci 2004; 75:2103-16. [PMID: 15312754 DOI: 10.1016/j.lfs.2004.04.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2003] [Accepted: 04/09/2004] [Indexed: 11/29/2022]
Abstract
Diabetic sensory neuropathy is an affliction that decreases sensory perception in a number of organ systems. Although little is known of its pulmonary effects certain diabetic patients have reduced airway reactivity to cold air and elevated cough threshold to irritant inhalation, reflexes reported to be mediated by pulmonary C-fibers. Therefore we studied the effects the selective C-fiber activator capsaicin (0.01% aerosol, 30 s) on variables of ventilation using a whole-body plethysmograph in age-matched rats treated with streptozotocin (STZ) or its vehicle at 6 and 12 weeks after treatment. Body weight increased and plasma glucose and glycosylated hemoglobin were stable in vehicle-treated rats. In STZ-treated rats body weight decreased and plasma glucose and glycosylated hemoglobin increased. Capsaicin challenge decreased tidal volume, respiratory rate and therefore minute ventilation in non-treated and vehicle-treated rats. However capsaicin challenge increased tidal volume thereby altering minute ventilation in STZ-treated rats. Specific airway resistance increased in both groups after capsaicin challenge. Changes in ventilation in response to capsaicin challenge in STZ-treated rats may involve C-fiber sensory neuropathy.
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Affiliation(s)
- Dale R Bergren
- Department of Biomedical Sciences, School of Medicine Creighton University, 2500 California Plaza, Omaha, NE 68178, USA.
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20
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Abstract
STUDY OBJECTIVES To evaluate cough reflex sensitivity in a population of young, healthy, male cigarette smokers. DESIGN Cross-sectional comparison. SETTING Academic medical center. PARTICIPANTS Twenty healthy, male current-smokers (mean [+/- SEM] age, 32.2 +/- 1.2 years). MEASUREMENTS Subjects underwent baseline spirometry followed by capsaicin cough challenge testing, which involved the inhalation of capsaicin in ascending, doubling concentrations until the concentrations inducing two or more coughs (C(2)) and those inducing five or more coughs (C(5)) were reached. The data were compared to those from a group of 50 healthy, male nonsmokers who had undergone identical cough challenge testing. RESULTS The two groups did not differ in terms of age or baseline pulmonary function. Cough sensitivity was significantly diminished in the current-smokers compared to control subjects. The mean (+/- SEM) log C(2) values in smokers and nonsmokers were 1.26 +/- 0.13 and 0.81 +/- 0.08, respectively (p = 0.004). The mean log C(5) values in smokers and nonsmokers were 2.03 +/- 0.10 and 1.20 +/- 0.08, respectively (p < 0.000001). CONCLUSIONS Cough reflex sensitivity is significantly diminished in young, healthy, male current-smokers compared to a similar population of nonsmokers. The mechanism of cough suppression in smokers remains speculative but may involve long-term tobacco smoke-induced desensitization of the cough receptors within the airway epithelium.
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