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Persson C. Airways exudation of plasma macromolecules: Innate defense, epithelial regeneration, and asthma. J Allergy Clin Immunol 2018; 143:1271-1286. [PMID: 30170125 PMCID: PMC7112321 DOI: 10.1016/j.jaci.2018.07.037] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 06/30/2018] [Accepted: 07/13/2018] [Indexed: 01/09/2023]
Abstract
This review discusses in vivo airway aspects of plasma exudation in relation to current views on epithelial permeability and epithelial regeneration in health and disease. Microvascular-epithelial exudation of bulk plasma proteins characteristically occurs in asthmatic patients, being especially pronounced in those with severe and exacerbating asthma. Healthy human and guinea pig airways challenged by noninjurious histamine-leukotriene–type autacoids also respond through prompt mucosal exudation of nonsieved plasma macromolecules. Contrary to current beliefs, epithelial permeability in the opposite direction (ie, absorption of inhaled molecules) has not been increased in patients with asthma and allergic rhinitis or in acutely exuding healthy airways. A slightly increased subepithelial hydrostatic pressure produces such unidirectional outward perviousness to macromolecules. Lack of increased absorption permeability in asthmatic patients can further be reconciled with occurrence of epithelial shedding, leaving small patches of denuded basement membrane. Counteracting escalating barrier breaks, plasma exudation promptly covers the denuded patches. Here it creates and sustains a biologically active barrier involving a neutrophil-rich, fibrin-fibronectin net. Furthermore, in the plasma-derived milieu, all epithelial cell types bordering the denuded patch dedifferentiate and migrate from all sides to cover the denuded basement membrane. However, this speedy epithelial regeneration can come at a cost. Guinea pig in vivo studies demonstrate that patches of epithelial denudation regeneration are exudation hot spots evoking asthma-like features, including recruitment/activation of granulocytes, proliferation of fibrocytes/smooth muscle cells, and basement membrane thickening. In conclusion, nonsieved plasma macromolecules can operate on the intact airway mucosa as potent components of first-line innate immunity responses. Exuded plasma also takes center stage in epithelial regeneration. When exaggerated, epithelial regeneration can contribute to the inception and development of asthma.
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Affiliation(s)
- Carl Persson
- Department of Laboratory Medicine, University Hospital of Lund, Lund, Sweden.
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Jones VC, Birrell MA, Maher SA, Griffiths M, Grace M, O'Donnell VB, Clark SR, Belvisi MG. Role of EP2 and EP4 receptors in airway microvascular leak induced by prostaglandin E2. Br J Pharmacol 2016; 173:992-1004. [PMID: 26639895 PMCID: PMC4831025 DOI: 10.1111/bph.13400] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 10/21/2015] [Accepted: 11/30/2015] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE Airway microvascular leak (MVL) involves the extravasation of proteins from post-capillary venules into surrounding tissue. MVL is a cardinal sign of inflammation and an important feature of airway inflammatory diseases such as asthma. PGE2, a product of COX-mediated metabolism of arachidonic acid, binds to four receptors, termed EP1–4. PGE2 has a wide variety of effects within the airway, including modulation of inflammation, sensory nerve activation and airway tone. However, the effect of PGE2 on airway MVL and the receptor/s that mediate this have not been described. EXPERIMENTAL APPROACH Evans Blue dye was used as a marker of airway MVL, and selective EP receptor agonists and antagonists were used alongside EP receptor-deficient mice to define the receptor subtype involved. KEY RESULTS PGE2 induced significant airway MVL in mice and guinea pigs. A significant reduction in PGE2-induced MVL was demonstrated in Ptger2−/− and Ptger4−/− mice and in wild-type mice pretreated simultaneously with EP2 (PF-04418948) and EP4 (ER-819762) receptor antagonists. In a model of allergic asthma, an increase in airway levels of PGE2 was associated with a rise in MVL; this change was absent in Ptger2−/− and Ptger4−/− mice. CONCLUSIONS AND IMPLICATIONS PGE2 is a key mediator produced by the lung and has widespread effects according to the EP receptor activated. Airway MVL represents a response to injury and under ‘disease’ conditions is a prominent feature of airway inflammation. The data presented highlight a key role for EP2 and EP4 receptors in MVL induced by PGE2.
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MESH Headings
- Allergens
- Animals
- Asthma/metabolism
- Azetidines/pharmacology
- Benzazepines/pharmacology
- Bronchi/metabolism
- Capillary Permeability
- Dinoprostone/analogs & derivatives
- Dinoprostone/metabolism
- Dinoprostone/pharmacology
- Guinea Pigs
- Imidazoles/pharmacology
- Male
- Methyl Ethers/pharmacology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Ovalbumin
- Receptors, Prostaglandin E, EP2 Subtype/agonists
- Receptors, Prostaglandin E, EP2 Subtype/antagonists & inhibitors
- Receptors, Prostaglandin E, EP2 Subtype/genetics
- Receptors, Prostaglandin E, EP2 Subtype/metabolism
- Receptors, Prostaglandin E, EP4 Subtype/agonists
- Receptors, Prostaglandin E, EP4 Subtype/antagonists & inhibitors
- Receptors, Prostaglandin E, EP4 Subtype/genetics
- Receptors, Prostaglandin E, EP4 Subtype/metabolism
- Trachea/metabolism
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3
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Mauser PJ, House A, Jones H, Correll C, Boyce C, Chapman RW. Pharmacological characterization of the late phase reduction in lung functions and correlations with microvascular leakage and lung edema in allergen-challenged Brown Norway rats. Pulm Pharmacol Ther 2013; 26:677-84. [PMID: 23523662 DOI: 10.1016/j.pupt.2013.03.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 03/04/2013] [Accepted: 03/07/2013] [Indexed: 10/27/2022]
Abstract
Late phase airflow obstruction and reduction in forced vital capacity are characteristic features of human asthma. Airway microvascular leakage and lung edema are also present in the inflammatory phase of asthma, but the impact of this vascular response on lung functions has not been precisely defined. This study was designed to evaluate the role of increased lung microvascular leakage and edema on the late phase changes in forced vital capacity (FVC) and peak expiratory flow (PEF) in allergen-challenged Brown Norway rats using pharmacological inhibitors of the allergic inflammatory response. Rats were sensitized and challenged with ovalbumin aerosol and forced expiratory lung functions (FVC, PEF) and wet and dry lung weights were measured 48 h after antigen challenge. Ovalbumin challenge reduced FVC (63% reduction) and PEF (33% reduction) and increased wet (65% increase) and dry (51% increase) lung weights. The antigen-induced reduction in FVC and PEF was completely inhibited by oral treatment with betamethasone and partially attenuated by inhibitors of arachidonic acid metabolism including indomethacin (cyclooxygenase inhibitor), 7-TM and MK-7246 (CRTH2 antagonists) and montelukast (CysLT1 receptor antagonist). Antagonists of histamine H1 receptors (mepyramine) and 5-HT receptors (methysergide) had no significant effects indicating that these pre-formed mast cell mediators were not involved. There was a highly significant (P < 0.005) correlation for the inhibition of FVC reduction and increase in wet and dry lung weights by these pharmacological agents. These results strongly support the hypothesis that lung microvascular leakage and the associated lung edema contribute to the reduction in forced expiratory lung functions in antigen-challenged Brown Norway rats and identify an important role for the cyclooxygenase and lipoxygenase products of arachidonic acid metabolism in these responses.
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Affiliation(s)
- Peter J Mauser
- Merck Research Laboratories, 2015, Galloping Hill Road, Kenilworth, NJ 07033-0539, USA.
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4
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Siddiqui S, Tsuchiya K, Risse PA, Bullimore SR, Benedetti A, Martin JG. Site of allergic airway narrowing and the influence of exogenous surfactant in the Brown Norway rat. PLoS One 2012; 7:e29381. [PMID: 22276110 PMCID: PMC3261862 DOI: 10.1371/journal.pone.0029381] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 11/28/2011] [Indexed: 11/18/2022] Open
Abstract
Background The parameters RN (Newtonian resistance), G (tissue damping), and H (tissue elastance) of the constant phase model of respiratory mechanics provide information concerning the site of altered mechanical properties of the lung. The aims of this study were to compare the site of allergic airway narrowing implied from respiratory mechanics to a direct assessment by morphometry and to evaluate the effects of exogenous surfactant administration on the site and magnitude of airway narrowing. Methods We induced airway narrowing by ovalbumin sensitization and challenge and we tested the effects of a natural surfactant lacking surfactant proteins A and D (Infasurf®) on airway responses. Sensitized, mechanically ventilated Brown Norway rats underwent an aerosol challenge with 5% ovalbumin or vehicle. Other animals received nebulized surfactant prior to challenge. Three or 20 minutes after ovalbumin challenge, airway luminal areas were assessed on snap-frozen lungs by morphometry. Results At 3 minutes, RN and G detected large airway narrowing whereas at 20 minutes G and H detected small airway narrowing. Surfactant inhibited RN at the peak of the early allergic response and ovalbumin-induced increase in bronchoalveolar lavage fluid cysteinyl leukotrienes and amphiregulin but not IgE-induced mast cell activation in vitro. Conclusion Allergen challenge triggers the rapid onset of large airway narrowing, detected by RN and G, and subsequent peripheral airway narrowing detected by G and H. Surfactant inhibits airway narrowing and reduces mast cell-derived mediators.
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Affiliation(s)
- Sana Siddiqui
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Kimitake Tsuchiya
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Paul-André Risse
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Sharon R. Bullimore
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Andrea Benedetti
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - James G. Martin
- Meakins-Christie Laboratories, Department of Medicine, McGill University, and the Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
- * E-mail:
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Khor YH, Teoh AKY, Lam SM, Mo DCQ, Weston S, Reid DW, Walters EH. Increased vascular permeability precedes cellular inflammation as asthma control deteriorates. Clin Exp Allergy 2009; 39:1659-67. [PMID: 19860817 DOI: 10.1111/j.1365-2222.2009.03349.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Airway microcirculation is abnormal in asthma but the role of vascular changes in asthma deteriorations remains poorly defined. We prospectively assessed the vascular changes accompanying worsening of asthma control by using an inhaled corticosteroid (ICS) dose-reduction model. OBJECTIVES To evaluate airway vascularity, vascular permeability and expression of vascular endothelial growth factor (VEGF) in early asthma deterioration induced by ICS back-titration. METHODS Twenty mild-to-moderate persistent symptomatic asthmatics on low-to-moderate ICS were recruited and treated with 4 weeks of high-dose fluticasone propionate (1000 microg/day) to achieve symptom control. This was followed by dose reduction to half of the pre-study doses for 4-8 weeks until the symptoms began to return. Endobronchial biopsy and bronchoalveolar lavage (BAL) samples were obtained after both treatment periods. RESULTS Vascularity as measured by the number and size of blood vessels, as well as VEGF expression did not change following ICS reduction. Even on high-dose ICS, perivascular albumin staining and BAL microalbumin levels in asthmatic subjects, as markers of permeability, were elevated when compared with normal subjects and both further increased significantly after ICS reduction. There was a significant association between changes in vascular leakiness and clinical deterioration. Increases in airway albumin correlated with previously reported increases in airway wall infiltration with T lymphocytes. CONCLUSIONS Our results suggest that airway vascular leakage is a major pathophysiologic feature of early asthma deterioration, occurring before recrudescence of cellular inflammation.
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Affiliation(s)
- Y H Khor
- Respiratory Research Group, Menzies Research Institute, University of Tasmania, Hobart, Tasmania, Australia.
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König P, Krain B, Krasteva G, Kummer W. Serotonin increases cilia-driven particle transport via an acetylcholine-independent pathway in the mouse trachea. PLoS One 2009; 4:e4938. [PMID: 19290057 PMCID: PMC2654158 DOI: 10.1371/journal.pone.0004938] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2008] [Accepted: 01/27/2009] [Indexed: 11/26/2022] Open
Abstract
Background Mucociliary clearance in the airways is driven by the coordinated beating of ciliated cells. Classical neuromediators such as noradrenalin and acetylcholine increase ciliary beat frequency and thus cilia-driven transport. Despite the fact that the neuromediator serotonin is ciliostimulatory in invertebrates and has been implied in releasing acetylcholine from the airway epithelium, its role in regulating cilia function in vertebrate airways is not established. Methodology/Principal Findings We examined the effects of serotonin on ciliary beat frequency and cilia-driven particle transport in the acutely excised submerged mouse trachea and determined the sources of serotonin in this tissue by immunohistochemistry. Serotonin (100 µM) increased cilary beat frequency (8.9±1.2 Hz to 17.0±2.7 Hz) and particle transport speed (38.9±4.6 µm/s to 83.4±8.3 µm/s) to an extent that was comparable to a supramaximal dose of ATP. The increase in particle transport speed was totally prevented by methysergide (100 µM). Blockade of muscarinic receptors by atropine (1 µM) did not reduce the effect of serotonin, although it was effective in preventing the increase in particle transport speed mediated by muscarine (100 µM). Immunohistochemistry demonstrated serotonin in mast cells pointing towards mast cells and platelets as possible endogenous sources of serotonin. Conclusions/Significance These results indicate that serotonin is a likely endogenous mediator that can increase cilia-driven transport independent from acetylcholine during activation of mast cells and platelets.
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Affiliation(s)
- Peter König
- Institut für Anatomie, Zentrum für medizinische Struktur- und Zellbiologie, Universität zu Lübeck, Lübeck, Germany.
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Theoharides TC, Kempuraj D, Tagen M, Vasiadi M, Cetrulo CL. Human umbilical cord blood-derived mast cells: a unique model for the study of neuro-immuno-endocrine interactions. ACTA ACUST UNITED AC 2007; 2:143-54. [PMID: 17237553 DOI: 10.1007/s12015-006-0021-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/24/2022]
Abstract
Findings obtained using animal models have often failed to reflect the processes involved in human disease. Moreover, human cultured cells do not necessarily function as their actual tissue counterparts. Therefore, there is great demand for sources of human progenitor cells that may be directed to acquire specific tissue characteristics and be available in sufficient quantities to carry out functional and pharmacological studies. Acase in point is the mast cell, well known for its involvement in allergic reactions, but also implicated in inflammatory diseases. Mast cells can be activated by allergens, anaphylatoxins, immunoglobulin-free light chains, superantigens, neuropeptides, and cytokines, leading to selective release of mediators. These could be involved in many inflammatory diseases, such as asthma and atopic dermatitis, which worsen by stress, through activation by local release of corticotropin-releasing hormone or related peptides. Umbilical cord blood and cord matrix-derived mast cell progenitors can be separated magnetically and grown in the presence of stem cell factor, interleukin-6, interleukin-4, and other cytokines to yield distinct mast cell populations. The recent use of live cell array, with its ability to study such interactions rapidly at the single-cell level, provides unique new opportunities for fast output screening of mast cell triggers and inhibitors.
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Affiliation(s)
- T C Theoharides
- Department of Laboratory of Molecular Immunopharmacology and Drug Discovery, Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, Boston, MA, USA.
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8
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Theoharides TC, Kalogeromitros D. The critical role of mast cells in allergy and inflammation. Ann N Y Acad Sci 2007; 1088:78-99. [PMID: 17192558 DOI: 10.1196/annals.1366.025] [Citation(s) in RCA: 219] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Mast cells are well known for their involvement in allergic and anaphylactic reactions, but recent findings implicate them in a variety of inflammatory diseases affecting different organs, including the heart, joints, lungs, and skin. In these cases, mast cells appear to be activated by triggers other than aggregation of their IgE receptors (FcepsilonRI), such as anaphylatoxins, immunoglobulin-free light chains, superantigens, neuropeptides, and cytokines leading to selective release of mediators without degranulation. These findings could explain inflammatory diseases, such as asthma, atopic dermatitis, coronary inflammation, and inflammatory arthritis, all of which worsen by stress. It is proposed that the pathogenesis of these diseases involve mast cell activation by local release of corticotropin-releasing hormone (CRH) or related peptides. Combination of CRH receptor antagonists and mast cell inhibitors may present novel therapeutic interventions.
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Affiliation(s)
- Theoharis C Theoharides
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, Boston, MA 02111, USA.
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Tigani B, Cannet C, Karmouty-Quintana H, Blé FX, Zurbruegg S, Schaeublin E, Fozard JR, Beckmann N. Lung inflammation and vascular remodeling after repeated allergen challenge detected noninvasively by MRI. Am J Physiol Lung Cell Mol Physiol 2006; 292:L644-53. [PMID: 17085517 DOI: 10.1152/ajplung.00122.2006] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Magnetic resonance imaging (MRI) has been used previously to follow noninvasively inflammatory processes in rat acute models of lung inflammation. Here the technique was applied to a model involving repeated intratracheal administration of ovalbumin (OA). Anatomical MRI was performed at different time points with respect to a single or multiple OA challenges in Brown Norway rats actively sensitized to the allergen. Vascular permeability was assessed using dynamic contrast-enhanced MRI (DCE-MRI). Bronchoalveolar lavage (BAL) fluid analysis and histology were performed to validate the MRI data. The time course of MRI signals after a single OA challenge reached a maximum at 48 h and decreased significantly at 96 h. After the second and subsequent challenges, the maximum signal occurred at 6 h with a time-dependent decline over the remainder of the time course. A reduction of the inflammatory response following repeated administration of OA was also detected by BAL fluid analysis. The decrease in vascular permeability assessed by DCE-MRI in repeatedly OA-challenged rats was consistent with the thickening of the vascular wall for vessels of diameter up to 300 microm revealed by histology. Angiogenesis of vessels smaller than 30 microm was also detected histologically. These results suggest that MRI can be used to detect the inflammatory response and vascular remodeling associated with chronic airway inflammation in rat models involving repeated administration of allergen. As the contrast agent used in the DCE-MRI experiments is approved for clinical use, there is potential to translate the approach to patients.
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Affiliation(s)
- Bruno Tigani
- Discovery Technologies Department, Novartis Institutes for BioMedical Research, Basel, Switzerland
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Pauluhn J, Mohr U. Experimental approaches to evaluate respiratory allergy in animal models. ACTA ACUST UNITED AC 2005; 56:203-34. [PMID: 15816351 DOI: 10.1016/j.etp.2004.10.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Asthma is defined as a chronic disease of the entire lung and asthma attacks may either be immediate, delayed or dual in onset. Allergic asthma is a complex chronic inflammatory disease of the airways and its etiology is multifactorial. It involves the recruitment and activation of many inflammatory and structural cells, all of which release mediators that result in typical pathological changes of asthma. A wealth of clinical and experimental data suggests that allergic asthma is due to an aberrant lung immune response mediated through T-helper type 2 (Th2) cells and associated cytokine-signaling pathways. The pathology of asthma is associated with reversible narrowing of airways, associated with prominent features that involve structural changes in the airway walls and extracellular matrix remodeling including abnormalities of bronchial smooth muscle, eosinophilic inflammation of the bronchial wall, hyperplasia and hypertrophy of mucous glands. The primary objective of respiratory allergy tests is to determine whether a low-molecular-weight chemical (hapten) or high-molecular-weight compound (antigen) exhibits sensitizing properties to the respiratory tract. This may range from reactions occurring in the nose (allergic rhinitis), in the bronchial airways (i.e., allergic bronchitis, asthma) or alveoli (e.g., hypersensitivity pneumonitis). Current assays utilize several phases, viz. an induction phase, which includes multiple exposures to the test compound (sensitization) via the respiratory tract (e.g., by intranasal or intratracheal instillations), by inhalation exposures or by dermal contact, and a single or multiple challenge or elicitation phase. The challenge can either be with the chemical (hapten), the homologous protein conjugate of the hapten or the antigen. The choice depends both on the irritant potency and the physical form (vapor, aerosol) of the hapten. The appropriate selection of concentrations (dosages) both for the induction and elicitation of respiratory allergy appears to be paramount for the outcome of test. Endpoints to characterize positive response range from the induction of immunoglobulins, cytokine or lymphokine patterns in serum (or the lung) to (patho-)physiological reactions typifying asthma. None of the currently applied animal models duplicate all features of human asthma. Accordingly, the specific pros and cons of the selected animal model, including protocol variables, animal species and strain selected, must be interpreted cautiously in order to arrive at a meaningful extrapolation for humans.
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Affiliation(s)
- Jürgen Pauluhn
- Institute of Toxicology, BA YER HealthCare, Wuppertal 42096, Germany.
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Suchankova J, Mata M, Cortijo J, Morcillo EJ. Effects of bemiparin on airway responses to antigen in sensitized Brown-Norway rats. Eur J Pharmacol 2004; 507:261-71. [PMID: 15659317 DOI: 10.1016/j.ejphar.2004.11.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Accepted: 11/10/2004] [Indexed: 11/18/2022]
Abstract
Heparins have demonstrated activity in asthma. The effects of bemiparin, a low molecular weight heparin, were examined on antigen-induced responses in sensitized Brown-Norway rats. Inhaled bemiparin (1 mg/ml) reduced the acute bronchospasm produced by aerosol antigen, prevented airway hyperresponsiveness to 5-hydroxytryptamine postantigen exposure, and reduced the eosinophil count (from 0.205+/-0.062 to 0.054+/-0.016 x 10(6) cells/ml in antigen and antigen+bemiparin groups, respectively; P<0.05), eosinophil peroxidase activity, and proteins in the bronchoalveolar lavage fluid (BALF), as well as the transiently augmented mucin Muc5ac expression. Hyperresponsiveness to adenosine was not affected by bemiparin. In similar experiments, inhaled fondaparinux (1 mg/ml) did not affect the antigen-induced responses, while a low-anticoagulant low molecular weight heparin was effective. In conclusion, bemiparin showed beneficial effects in experimental asthma, probably unrelated to its anticoagulant activity, which extends the previous positive findings obtained with other heparins.
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Affiliation(s)
- Jana Suchankova
- Department of Pharmacology, University of Valencia, Avenida Blasco Ibanez 15, E-46010 Valencia, Spain
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12
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Lan RS, Stewart GA, Henry PJ. Role of protease-activated receptors in airway function: a target for therapeutic intervention? Pharmacol Ther 2003; 95:239-57. [PMID: 12243797 DOI: 10.1016/s0163-7258(02)00237-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protease-activated receptors (PARs) are G-protein-coupled, seven transmembrane domain receptors that act as cellular enzyme sensors. These receptors are activated by the proteolytic cleavage at the amino terminus, enabling interaction between the newly formed "tethered ligand" and the second extracellular loop of the receptor to confer cellular signalling. PARs can also be activated by small peptides that mimic the tethered ligand. In the respiratory tract, PARs may be regulated by endogenous proteases, such as airway trypsin and mast cell tryptase, as well as exogenous proteases, including inhaled aeroallergens such as those from house dust mite faecal pellets. Immunoreactive PARs have been identified in multiple cell types of the respiratory tract, and PAR activation has been reported to stimulate cellular mitogenesis and to promote tissue inflammation. Activation of PARs concurrently stimulates the release of bronchorelaxant and anti-inflammatory mediators, which may serve to induce cytoprotection and to minimise tissue trauma associated with severe chronic airways inflammation. Furthermore, airway inflammatory responses are associated with increased epithelial PAR expression and elevated concentrations of PAR-activating, and PAR-inactivating, proteases in the extracellular space. On this basis, PARs are likely to play a regulatory role in airway homeostasis, and may participate in respiratory inflammatory disorders, such as asthma and chronic obstructive pulmonary disease. Further studies focussing on the effects of newly developed PAR agonists and antagonists in appropriate models of airway inflammation will permit better insight into the role of PARs in respiratory pathophysiology and their potential as therapeutic targets.
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Affiliation(s)
- Rommel S Lan
- Department of Pharmacology, QEII Medical Centre, The University of Western Australia, Nedlands, Western Australia 6009, Perth, Australia
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Blesa S, Cortijo J, Martinez-Losa M, Mata M, Seda E, Santangelo F, Morcillo EJ. Effectiveness of oral N -acetylcysteine in a rat experimental model of asthma. Pharmacol Res 2002; 45:135-40. [PMID: 11846626 DOI: 10.1006/phrs.2001.0917] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Oxidative stress appears to be relevant to asthma pathogenesis. Therefore, the effectiveness of the antioxidant N -acetylcysteine was examined on antigen-induced pulmonary responses in sensitized Brown-Norway rats. N -acetylcysteine (oral, 1 mmol kg(-1)per day for 7 days before challenge) did not reduce the immediate bronchospasm that followed aerosol antigen exposure but prevented airway hyperreactivity to 5-hydroxytryptamine at 24 h after antigen challenge, and reduced the eosinophils (from 0.178 +/- 0.038 in the absence to 0.064 +/- 0.020 x10(6)cells ml(-1)in the presence of N -acetylcysteine;P< 0.05), and Evans blue dye extravasation in bronchoalveolar lavage fluid. Taurine levels in bronchoalveolar lavage fluid from antigen-challenged rats were higher than control values but treatment with N -acetylcysteine failed to further increase these augmented levels. In conclusion, oral N -acetylcysteine showed beneficial effects in an in vivo model of experimental asthma, which confirm and extend the previous positive findings obtained in other models of lung injury.
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Affiliation(s)
- S Blesa
- Department of Pharmacology, Faculty of Medicine, University of Valencia, Av. Blasco Ibanez 15, E-46010 Valencia, Spain
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Cortijo J, Blesa S, Martinez-Losa M, Mata M, Seda E, Santangelo F, Morcillo EJ. Effects of taurine on pulmonary responses to antigen in sensitized Brown-Norway rats. Eur J Pharmacol 2001; 431:111-7. [PMID: 11716849 DOI: 10.1016/s0014-2999(01)01433-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxidative stress appears relevant to asthma. Therefore, the effects of the antioxidant taurine (oral, 1 and 3 mmol x kg(-1) x day(-1) for 7 days before challenge) were examined on antigen-induced responses in sensitized Brown-Norway rats. Taurine did not reduce the bronchospasm produced by aerosol antigen but prevented airway hyperreactivity to 5-hydroxytryptamine (5-HT) at 24 h after antigen exposure, and reduced the eosinophils (from 0.178+/-0.038x10(6) to 0.044+/-0.014x10(6)* and 0.048+/-0.013x10(6)* cells ml(-1) in antigen and antigen+taurine 1 or 3 mmol x kg(-1), respectively; *P<0.05 vs. antigen), lipid hydroperoxides, and Evans blue dye extravasation in bronchoalveolar lavage fluid. Taurine levels in bronchoalveolar lavage fluid from antigen-challenged rats were higher than control values but treatment with taurine failed to further increase these levels. In conclusion, oral taurine showed beneficial effects in an in vivo model of experimental asthma, which confirm and extend the previous positive findings obtained in other models of lung injury.
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Affiliation(s)
- J Cortijo
- Department of Pharmacology, Faculty of Medicine, University of Valencia, Avenida Blasco Ibanez 15, E-46010, Valencia, Spain
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Kwan ML, Gómez AD, Baluk P, Hashizume H, McDonald DM. Airway vasculature after mycoplasma infection: chronic leakiness and selective hypersensitivity to substance P. Am J Physiol Lung Cell Mol Physiol 2001; 280:L286-97. [PMID: 11159008 DOI: 10.1152/ajplung.2001.280.2.l286] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Angiogenesis and microvascular remodeling are features of chronic airway inflammation caused by Mycoplasma pulmonis infection in rats. As airway blood vessels undergo remodeling, they become unusually sensitive to substance P-induced plasma leakage. Here we determined whether the remodeled vessels are leaky under baseline conditions, whether their heightened sensitivity is specific to substance P, and whether the leakage is reversible. Four weeks after infection, the amount of baseline leakage of Evans blue in the tracheal mucosa was two to five times the normal level. Gaps < 1 microm in diameter were located between endothelial cells in some remodeled vessels. Substance P, but not platelet-activating factor or 5-hydroxytryptamine, produced an exaggerated leakage response. Inhalation of the beta2-adrenergic receptor agonist salmeterol reduced the leakage by <60%. We conclude that the blood vessel remodeling after M. pulmonis infection is associated with microvascular leakiness due, in part, to the formation of endothelial gaps. This leakage is accompanied by an abnormal sensitivity to substance P but not to platelet-activating factor or 5-hydroxytryptamine and can be reduced by beta2-agonists.
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Affiliation(s)
- M L Kwan
- Cardiovascular Research Institute and Department of Anatomy, University of California, San Francisco, California 94143, USA
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