901
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Edwards MR, Kebadze T, Johnson MW, Johnston SL. New treatment regimes for virus-induced exacerbations of asthma. Pulm Pharmacol Ther 2005; 19:320-34. [PMID: 16289761 PMCID: PMC7172610 DOI: 10.1016/j.pupt.2005.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 09/21/2005] [Accepted: 09/23/2005] [Indexed: 02/06/2023]
Abstract
This review will focus on the role of viruses as causes of asthma exacerbations. The article will briefly review the current literature supporting this view, with a special focus on human rhinovirus (RV), the main virus associated with exacerbations of asthma. The review will then refer to possible strategies for treatment, and will include discussion on treatment with specific anti-viral therapy and type I interferon as a treatment for RV. The review will also include a discussion on current therapies for asthma, such as glucocorticosteroid and beta(2) agonist therapy alone and in combination and why this may be relevant to virus-induced exacerbations of asthma. Finally, the potential for future anti-inflammatory/immunomodulatory therapies with a focus on NF-kappaB inhibition will be discussed.
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Affiliation(s)
- Michael R Edwards
- Department of Respiratory Medicine, Wright Fleming Institute of Infection & Immunity, National Heart Lung Institute, Imperial College London, UK.
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902
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Abstract
BACKGROUND Viral respiratory tract infections cause significant morbidity and mortality. Respiratory viruses are suspected to play a role in the inception of asthma early in life. Respiratory syncytial virus (RSV) is the most common cause of infant bronchiolitis, which is associated with the development of childhood wheezing and asthma. However, it is not clear whether this association is "causal" or "circumstantial." METHODS Animal models have been pivotal in studying the pathophysiology of viral respiratory infections. Various approaches to assessing airway inflammation and function have been used to define the mechanisms of virus-induced airway dysfunction and to address clinically relevant questions regarding the role of RSV in wheezing and asthma after bronchiolitis. RESULTS Viral lower respiratory tract infections alter airway function in humans and animals. The extent and duration of the alterations may depend on the virus itself, host factors and environmental factors. Animal studies demonstrated that viral infection induces airway hyperresponsiveness and enhances this alteration in the allergen-sensitized and exposed host. This altered airway function is mediated by immune and neurogenic inflammatory mechanisms. Recent studies in mice show that neonatal RSV infection sensitizes the newborn to develop an asthma-like phenotype on reinfection, providing further opportunities to investigate the role of RSV in postbronchiolitis wheezing and asthma in this animal model. CONCLUSIONS Further studies are needed to fully establish the mechanisms underlying the pathophysiology of viral respiratory tract infections and to clarify their role in the inception and/or progression of chronic airway diseases such as asthma. The results of ongoing therapeutic studies promise to minimize the impact of such viral infections.
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Affiliation(s)
- Azzeddine Dakhama
- Division of Cell Biology, Department of Pediatrics, National Jewish Medical and Research Center, Denver, CO, USA.
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903
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Heymann PW, Platts-Mills TAE, Johnston SL. Role of viral infections, atopy and antiviral immunity in the etiology of wheezing exacerbations among children and young adults. Pediatr Infect Dis J 2005; 24:S217-22, discussion S220-1. [PMID: 16378049 DOI: 10.1097/01.inf.0000188164.33856.f9] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND At least 101 serotypes of rhinoviruses have been identified. Rhinoviruses have often been associated with trivial upper respiratory infections but more recent evidence suggests that they play a significant role in the pathogenesis of asthma exacerbations. METHODS The impact of rhinoviruses as a cause of respiratory morbidity in infancy and the role of rhinoviruses in causing asthma exacerbations in the children and adult population is discussed. Past and current experimental and epidemiologic evidence was assessed to suggest a causal role rather than just an association. Mechanism of susceptibility to virus infection in asthmatics were discussed, as were data indicating important interactions between allergic sensitization and rhinovirus infections in risk of asthma exacerbations. RESULTS Asthmatic individuals have increased severity and duration of lower airway symptoms and greater declines in lung function upon infection with rhinovirus, suggesting greater susceptibility to rhinovirus infection because of impaired antiviral immunity. Early virus-induced apoptosis, which aborts virus replication, was impaired in asthmatics. Treating allergic airway inflammation may reduce the frequency and severity of symptoms triggered by rhinoviruses. CONCLUSIONS The evidence in children and young adults suggests that atopy and allergic inflammation in the airways may be critical determinants of an adverse response to rhinovirus. Increased awareness of the spectrum of age groups that are affected by rhinoviruses is needed to encourage the development of new treatments and strategies that may be helpful in reducing the frequency and severity of symptoms triggered by rhinoviruses.
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Affiliation(s)
- Peter W Heymann
- Department of Pediatrics, University of Virginia Asthma and Allergic Diseases Center, PO Box 800386, Charlottesville, VA 22908, USA.
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904
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Johnston SL, Martin RJ. Chlamydophila pneumoniae and Mycoplasma pneumoniae: a role in asthma pathogenesis? Am J Respir Crit Care Med 2005; 172:1078-89. [PMID: 15961690 DOI: 10.1164/rccm.200412-1743pp] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The potential role of atypical bacterial infection in the pathogenesis of asthma is a subject of continuing debate. There is an increasing body of literature concerning the association between the atypical bacteria Chlamydophila pneumoniae and Mycoplasma pneumoniae and asthma pathogenesis; however, many studies investigating such a link have been uncontrolled and have provided conflicting evidence, in part due to the difficulty in accurately diagnosing infection with these atypical pathogens. This article reviews the evidence for an association between atypical bacterial respiratory pathogens and the pathogenesis of asthma, and discusses the biological mechanisms that could account for such a link. The possible role of antibacterial therapy in the management of asthma and the need for well-designed studies to investigate this is also discussed.
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Affiliation(s)
- Sebastian L Johnston
- Department of Respiratory Medicine, National Heart and Lung Institute and Wright Fleming Institute of Infection and Immunity, Imperial College London, Norfolk Place, London W2 1PG, UK.
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905
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Hewson CA, Jardine A, Edwards MR, Laza-Stanca V, Johnston SL. Toll-like receptor 3 is induced by and mediates antiviral activity against rhinovirus infection of human bronchial epithelial cells. J Virol 2005; 79:12273-9. [PMID: 16160153 PMCID: PMC1211516 DOI: 10.1128/jvi.79.19.12273-12279.2005] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Rhinoviruses (RV) are the major cause of the common cold and acute exacerbations of asthma and chronic obstructive pulmonary disease. Toll-like receptors (TLRs) are a conserved family of receptors that recognize and respond to a variety of pathogen-associated molecular patterns. TLR3 recognizes double-stranded RNA, an important intermediate of many viral life cycles (including RV). The importance of TLR3 in host responses to virus infection is not known. Using BEAS-2B (a human bronchial epithelial cell-line), we demonstrated that RV replication increased the expression of TLR3 mRNA and TLR3 protein on the cell surface. We observed that blocking TLR3 led to a decrease in interleukin-6, CXCL8, and CCL5 in response to poly(IC) but an increase following RV infection. Finally, we demonstrated that TLR3 mediated the antiviral response. This study demonstrates an important functional requirement for TLR3 in the host response against live virus infection and indicates that poly(IC) is not always a good model for studying the biology of live virus infection.
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Affiliation(s)
- Christopher A Hewson
- Department of Respiratory Medicine, National Heart and Lung Institute and Wright Fleming Institute of Infection and Immunity, Imperial College London, Norfolk Place, London W2 1PG, United Kingdom
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906
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Bossios A, Psarras S, Gourgiotis D, Skevaki CL, Constantopoulos AG, Saxoni-Papageorgiou P, Papadopoulos NG. Rhinovirus infection induces cytotoxicity and delays wound healing in bronchial epithelial cells. Respir Res 2005; 6:114. [PMID: 16216126 PMCID: PMC1283981 DOI: 10.1186/1465-9921-6-114] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2005] [Accepted: 10/10/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Human rhinoviruses (RV), the most common triggers of acute asthma exacerbations, are considered not cytotoxic to the bronchial epithelium. Recent observations, however, have questioned this knowledge. The aim of this study was to evaluate the ability of RV to induce epithelial cytotoxicity and affect epithelial repair in-vitro. METHODS Monolayers of BEAS-2B bronchial epithelial cells, seeded at different densities were exposed to RV serotypes 1b, 5, 7, 9, 14, 16. Cytotoxicity was assessed chromatometrically. Epithelial monolayers were mechanically wounded, exposed or not to RV and the repopulation of the damaged area was assessed by image analysis. Finally epithelial cell proliferation was assessed by quantitation of proliferating cell nuclear antigen (PCNA) by flow cytometry. RESULTS RV1b, RV5, RV7, RV14 and RV16 were able to induce considerable epithelial cytotoxicity, more pronounced in less dense cultures, in a cell-density and dose-dependent manner. RV9 was not cytotoxic. Furthermore, RV infection diminished the self-repair capacity of bronchial epithelial cells and reduced cell proliferation. CONCLUSION RV-induced epithelial cytotoxicity may become considerable in already compromised epithelium, such as in the case of asthma. The RV-induced impairment on epithelial proliferation and self-repair capacity may contribute to the development of airway remodeling.
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Affiliation(s)
- Apostolos Bossios
- Allergy Department, 2nd Pediatric Clinic, University of Athens, Athens, Greece
| | - Stelios Psarras
- Allergy Department, 2nd Pediatric Clinic, University of Athens, Athens, Greece
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907
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Chen Y, Hamati E, Lee PK, Lee WM, Wachi S, Schnurr D, Yagi S, Dolganov G, Boushey H, Avila P, Wu R. Rhinovirus induces airway epithelial gene expression through double-stranded RNA and IFN-dependent pathways. Am J Respir Cell Mol Biol 2005; 34:192-203. [PMID: 16210696 PMCID: PMC2644182 DOI: 10.1165/rcmb.2004-0417oc] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Rhinovirus (RV) infection is the major cause of common colds and of asthma exacerbations. Because the epithelial cell layer is the primary target of RV infection, we hypothesize that RV-induced airway disease is associated with the perturbation of airway epithelial gene expression. In this study, well differentiated primary human airway epithelial cells were infected with either RV16 (major group) or RV1B (minor group). Transcriptional gene profiles from RV-infected and mock-infected control cells were analyzed by Affymetrix Genechip, and changes of the gene expression were confirmed by real-time RT-PCR analysis. At 24 h after infection, 48 genes induced by both viruses were identified. Most of these genes are related to the IFN pathway, and have been documented to have antiviral functions. Indeed, a significant stimulation of IFN-beta secretion was detected after RV16 infection. Neutralizing antibody specific to IFN-beta and a specific inhibitor of the Janus kinase pathway both significantly blocked the induction of RV-inducible genes. Further studies demonstrated that 2-aminopurine, a specific inhibitor double-stranded RNA-dependent protein kinase, could block both IFN-beta production and RV-induced gene expression. Thus, IFN-beta-dependent pathway is a part of the double-stranded RNA-initiated pathway that is responsible for RV-induced gene expression. Consistent with its indispensable role in the induction of antiviral genes, deactivation of this signaling pathway significantly enhanced viral production. Because increase of viral yield is associated with the severity of RV-induced airway illness, the discovery of an epithelial antiviral signaling pathway in this study will contribute to our understanding of the pathogenesis of RV-induced colds and asthma exacerbations.
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Affiliation(s)
- Yin Chen
- Center for Comparative Respiratory Biology and Medicine, Genomic and Biomedical Sciences Facility, Suite 6510, University of California at Davis, One Shields Ave., Davis, CA 95616, USA.
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908
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Rolph MS, Sisavanh M, Liu SM, Mackay CR. Clues to asthma pathogenesis from microarray expression studies. Pharmacol Ther 2005; 109:284-94. [PMID: 16203040 DOI: 10.1016/j.pharmthera.2005.08.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Accepted: 08/24/2005] [Indexed: 11/27/2022]
Abstract
Asthma is a chronic inflammatory disease characterized by airway hyperresponsiveness (AHR), tissue remodeling, and airflow obstruction. The pathogenesis of asthma is only partly understood, and there is an urgent need for improved therapeutic strategies for this disease. Microarray technology has considerable promise as a tool for discovery of novel asthma therapeutic targets, although the field is still in its infancy. A number of studies have described expression profiles derived from human asthmatic lung tissue, mouse airway tissue, or from key cell types associated with asthma, but to date relatively few studies have exploited these findings to discover new pathways involved in the pathogenesis of asthma. Among the genes to have been identified by array studies and validated by further studies are monokine induced by interferon (IFN)-gamma, fatty acid binding proteins (FABP), and complement factor 5 (C5). Here we provide examples of microarray approaches to the discovery of new molecules associated with asthma. We anticipate that these types of analyses will provide considerable insight into asthma pathogenesis and will provide a wealth of new molecules for downstream analyses such as gene deficient mouse studies, or monoclonal antibody production.
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Affiliation(s)
- Michael S Rolph
- Arthritis and Inflammation Research Program, Garvan Institute for Medical Research, Darlinghurst, Australia.
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909
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Xepapadaki P, Papadopoulos NG, Bossios A, Manoussakis E, Manousakas T, Saxoni-Papageorgiou P. Duration of postviral airway hyperresponsiveness in children with asthma: effect of atopy. J Allergy Clin Immunol 2005; 116:299-304. [PMID: 16083783 PMCID: PMC7172284 DOI: 10.1016/j.jaci.2005.04.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2004] [Revised: 03/28/2005] [Accepted: 04/04/2005] [Indexed: 12/16/2022]
Abstract
Background Respiratory viruses induce asthma exacerbations and airway hyperresponsiveness (AHR). Atopy is an important risk factor for asthma persistence. Objective We sought to evaluate whether atopy is a risk factor for prolonged AHR after upper respiratory tract infections (URIs). Methods Twenty-five children (13 atopic and 12 nonatopic children) with intermittent virus-induced asthma were studied. Clinical evaluation, skin prick tests, methacholine bronchoprovocation, questionnaires, and a nasal wash specimen were obtained at baseline. For 9 months, subjects completed diary cards with respiratory symptoms. During their first reported cold, a nasal wash specimen was obtained. Methacholine provocation was performed 10 days and 5, 7, 9, and 11 weeks later. In case a new cold developed, the provocation schedule was followed from the beginning. Results Viruses were detected in 17 (68%) of 25 patients during their first cold, with rhinovirus being most commonly identified (82%). AHR increased significantly 10 days after the URI, equally in both groups (P = .67), and remained so up to the fifth week. Duration of AHR in subjects experiencing a single URI ranged from 5 to 11 weeks, without a significant difference between groups. In the duration of the study, atopic children experienced more colds and asthma exacerbations than nonatopic children. Thus for duration of AHR, significant prolongation was noted in the atopic group when assessed cumulatively. Conclusion In asthmatic children the duration of AHR after a single natural cold is 5 to 11 weeks. However, an increased rate of symptomatic cold and asthma episodes in atopic children is associated with considerable cumulative prolongation of AHR, which might help explain the role of atopy as a risk factor for asthma persistence.
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Affiliation(s)
- Paraskevi Xepapadaki
- Reprint requests: Paraskevi Xepapadaki, MD, PhD, UPC Research Laboratories, 13, Levadias 11527, Goudi, Greece.
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910
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van Rijt LS, van Kessel CHG, Boogaard I, Lambrecht BN. Respiratory viral infections and asthma pathogenesis: a critical role for dendritic cells? J Clin Virol 2005; 34:161-9. [PMID: 16126001 DOI: 10.1016/j.jcv.2005.07.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2005] [Indexed: 11/27/2022]
Abstract
BACKGROUND Respiratory viral infections can influence the course of asthma at different time points. Severe respiratory viral infections during early age are associated with a higher prevalence of asthma in later childhood. In established asthma, viral infections are a frequent cause of asthma exacerbation. OBJECTIVES The present review focuses on epidemiological and experimental animal data that can illuminate the mechanisms by which viral infections can lead to sensitization to antigen, and exacerbate ongoing allergic airway inflammation and focuses on the role played by dendritic cells (DCs). RESULTS In experimental rodent models of asthma, respiratory viral infection at the time of a first inhaled antigen exposure is described to induce Th2 sensitization and to enhance the allergic response to a second encounter with the same antigen. Virus infections can modulate airway dendritic cell function by upregulation of costimulatory molecule expression, enhanced recruitment, and by inducing an inflammatory environment, all leading to an enhanced antigen presentation and possibly changing the normal tolerogenic response to inhaled antigen into an immunogenic response. In established asthma, respiratory viral infections attract several inflammatory cells, alter receptor expression on airway smooth muscle and modulate neuroimmune mechanisms, possibly leading to exacerbation of disease. CONCLUSIONS Animal data suggest that the link between respiratory viral infections and increased asthma is causally related, the viral infection acting on the immune and structural cells to enhance antigen presentation and inflammatory cell recruitment.
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Affiliation(s)
- Leonie S van Rijt
- Erasmus University Medical Center, Room Ee2257a, Department of Pulmonary Medicine, Dr Molewaterplein 50, Erasmus MC, 3015 GE Rotterdam, The Netherlands.
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911
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Xatzipsalti M, Kyrana S, Tsolia M, Psarras S, Bossios A, Laza-Stanca V, Johnston SL, Papadopoulos NG. Rhinovirus viremia in children with respiratory infections. Am J Respir Crit Care Med 2005; 172:1037-40. [PMID: 15994468 DOI: 10.1164/rccm.200502-315oc] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
RATIONALE Viremia has been implicated in many viral infections; however, viremia due to rhinovirus (RV; rhinoviremia) has been considered not to occur in normal individuals. OBJECTIVE To evaluate whether RV enters the bloodstream and identify the possible risk factors. METHODS Nasopharyngeal washes (NPWs) of 221 children with respiratory infections were examined for the presence of RV by reverse transcription-polymerase chain reaction. Blood from 88 children, whose NPW was RV-positive, and 31 of RV-negative control subjects was subsequently examined for the presence of RV in the blood by semi-nested reverse transcription-polymerase chain reaction. Rhinoviremia was then correlated with clinical characteristics of the disease. RESULTS RV was detected in the blood of 10 out of 88 NPW RV-positive cases (11.4%): 7 of 28 children with asthma exacerbations (25.0%), 2 of 26 with common cold (7.7%), 1 of 25 with bronchiolitis (4.0%), and 0 of 9 with pneumonia (0%). All NPW RV-negative cases were negative in the blood. The proportion of rhinoviremia in children with asthma exacerbation was significantly higher compared with children suffering from the other diseases (25 vs. 5%, p = 0.01). Significant risk factors were: sampling <or= 24 hours from symptom initiation, personal history of asthma, and male sex. Age, fever, family, and personal history of atopy did not affect the presence of RV in the blood. CONCLUSIONS Viremia may occur during RV respiratory infections in normal children and is rather common in the early course of acute asthma exacerbations, suggesting that rhinoviremia may be involved in asthma exacerbation pathogenesis.
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Affiliation(s)
- Maria Xatzipsalti
- Allergy Department, Second Pediatric Clinic, University of Athens, Athens, Greece
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912
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