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Milad N, Morissette MC. Revisiting the role of pulmonary surfactant in chronic inflammatory lung diseases and environmental exposure. Eur Respir Rev 2021; 30:30/162/210077. [PMID: 34911693 DOI: 10.1183/16000617.0077-2021] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 08/05/2021] [Indexed: 12/12/2022] Open
Abstract
Pulmonary surfactant is a crucial and dynamic lung structure whose primary functions are to reduce alveolar surface tension and facilitate breathing. Though disruptions in surfactant homeostasis are typically thought of in the context of respiratory distress and premature infants, many lung diseases have been noted to have significant surfactant abnormalities. Nevertheless, preclinical and clinical studies of pulmonary disease too often overlook the potential contribution of surfactant alterations - whether in quantity, quality or composition - to disease pathogenesis and symptoms. In inflammatory lung diseases, whether these changes are cause or consequence remains a subject of debate. This review will outline 1) the importance of pulmonary surfactant in the maintenance of respiratory health, 2) the diseases associated with primary surfactant dysregulation, 3) the surfactant abnormalities observed in inflammatory pulmonary diseases and, finally, 4) the available research on the interplay between surfactant homeostasis and smoking-associated lung disease. From these published studies, we posit that changes in surfactant integrity and composition contribute more considerably to chronic inflammatory pulmonary diseases and that more work is required to determine the mechanisms underlying these alterations and their potential treatability.
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Affiliation(s)
- Nadia Milad
- Faculty of Medicine, Université Laval, Quebec City, QC, Canada.,Quebec Heart and Lung Institute - Université Laval, Quebec City, QC, Canada
| | - Mathieu C Morissette
- Quebec Heart and Lung Institute - Université Laval, Quebec City, QC, Canada .,Dept of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
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2
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Yoshida Y, Takaku Y, Nakamoto Y, Takayanagi N, Yanagisawa T, Takizawa H, Kurashima K. Changes in airway diameter and mucus plugs in patients with asthma exacerbation. PLoS One 2020; 15:e0229238. [PMID: 32106233 PMCID: PMC7046273 DOI: 10.1371/journal.pone.0229238] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 02/01/2020] [Indexed: 11/18/2022] Open
Abstract
Background Airway obstruction due to decreased airway diameter and increased incidence of mucus plugs has not been directly observed in asthma exacerbation. We studied the changes in the inner diameter of the airway (Din) and the frequency of mucus plugs by airway generation in patients with asthma exacerbation. We compared these patients to those in a stable phase using high-resolution computed tomography (HRCT). Methods and findings Thirteen patients with asthma were studied by HRCT during asthma exacerbation and in a stable period. The HRCT study was performed on patients who could safely hold their breath for a short while in a supine position 1 hour after initial treatment for asthma exacerbation. Using a curved multiplanar reconstruction (MPR) software, we reconstructed the longitudinal airway images and the images exactly perpendicular to the airway axis to measure the Din and mucus plugs from the second- (segmental) to sixth-generation bronchi in all segments of the lungs.The ratios of Din (exacerbation/stable) were 0.91(P = 0.016), 0.88 (P = 0.002), 0.83 (P = 0.001), 0.80 (P = 0.001), and 0.87 (NS) in the second-, third-, fourth-, fifth-, and sixth-generation bronchi, respectively. The percentages of airway obstruction due to mucus plugs were notably higher in the fourth- and fifth-generation bronchi (17.9%/18.1% in stable phase and 43.2%/45.9% in the exacerbation phase, respectively) than in the other generations of bronchi. Conclusions Among the bronchi examined, the fourth- and fifth-generation bronchi were significantly obstructed during asthma exacerbation compared with the stable phase in terms of a decreased airway diameter and mucus plugs.
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Affiliation(s)
- Yuki Yoshida
- Department of Respiratory Medicine, Saitama Cardiovascular and Respiratory Center, Kumagaya City, Saitama, Japan
- Department of Respiratory Medicine, Kyorin University School of Medicine, Mitaka city, Tokyo, Japan
| | - Yotaro Takaku
- Department of Respiratory Medicine, Saitama Cardiovascular and Respiratory Center, Kumagaya City, Saitama, Japan
- * E-mail:
| | - Yasuo Nakamoto
- Department of Respiratory Medicine, Saitama Cardiovascular and Respiratory Center, Kumagaya City, Saitama, Japan
| | - Noboru Takayanagi
- Department of Respiratory Medicine, Saitama Cardiovascular and Respiratory Center, Kumagaya City, Saitama, Japan
| | - Tsutomu Yanagisawa
- Department of Respiratory Medicine, Saitama Cardiovascular and Respiratory Center, Kumagaya City, Saitama, Japan
| | - Hajime Takizawa
- Department of Respiratory Medicine, Kyorin University School of Medicine, Mitaka city, Tokyo, Japan
| | - Kazuyoshi Kurashima
- Department of Respiratory Medicine, Saitama Cardiovascular and Respiratory Center, Kumagaya City, Saitama, Japan
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3
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Electronic cigarette vapor alters the lateral structure but not tensiometric properties of calf lung surfactant. Respir Res 2017; 18:193. [PMID: 29149889 PMCID: PMC5693547 DOI: 10.1186/s12931-017-0676-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 10/25/2017] [Indexed: 12/24/2022] Open
Abstract
Background Despite their growing popularity, the potential respiratory toxicity of electronic cigarettes (e-cigarettes) remains largely unknown. One potential aspect of e-cigarette toxicity is the effect of e-cigarette vapor on lung surfactant function. Lung surfactant is a mixture of lipids and proteins that lines the alveolar region. The surfactant layer reduces the surface tension of the alveolar fluid, thereby playing a crucial role in lung stability. Due to their small size, particulates in e-cigarette vapor can penetrate the deep lungs and come into contact with the lung surfactant. The current study sought to examine the potential adverse effects of e-cigarette vapor and conventional cigarette smoke on lung surfactant interfacial properties. Methods Infasurf®, a clinically used and commercially available calf lung surfactant extract, was used as lung surfactant model. Infasurf® films were spread on top of an aqueous subphase in a Langmuir trough with smoke particulates from conventional cigarettes or vapor from different flavors of e-cigarettes dispersed in the subphase. Surfactant interfacial properties were measured in real-time upon surface compression while surfactant lateral structure after exposure to smoke or vapor was examined using atomic force microscopy (AFM). Results E-cigarette vapor regardless of the dose and flavoring of the e-liquid did not affect surfactant interfacial properties. In contrast, smoke from conventional cigarettes had a drastic, dose-dependent effect on Infasurf® interfacial properties reducing the maximum surface pressure from 65.1 ± 0.2 mN/m to 46.1 ± 1.3 mN/m at the highest dose. Cigarette smoke and e-cigarette vapor both altered surfactant microstructure resulting in an increase in the area of lipid multilayers. Studies with individual smoke components revealed that tar was the smoke component most disruptive to surfactant function. Conclusions While both e-cigarette vapor and conventional cigarette smoke affect surfactant lateral structure, only cigarette smoke disrupts surfactant interfacial properties. The surfactant inhibitory compound in conventional cigarettes is tar, which is a product of burning and is thus absent in e-cigarette vapor.
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Calkovska A, Uhliarova B, Joskova M, Franova S, Kolomaznik M, Calkovsky V, Smolarova S. Pulmonary surfactant in the airway physiology: a direct relaxing effect on the smooth muscle. Respir Physiol Neurobiol 2015; 209:95-105. [PMID: 25583659 DOI: 10.1016/j.resp.2015.01.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 01/05/2015] [Accepted: 01/05/2015] [Indexed: 12/13/2022]
Abstract
Beside alveoli, surface active material plays an important role in the airway physiology. In the upper airways it primarily serves in local defense. Lower airway surfactant stabilizes peripheral airways, provides the transport and defense, has barrier and anti-edematous functions, and possesses direct relaxant effect on the smooth muscle. We tested in vitro the effect of two surfactant preparations Curosurf® and Alveofact® on the precontracted smooth muscle of intra- and extra-pulmonary airways. Relaxation was more pronounced for lung tissue strip containing bronchial smooth muscle as the primary site of surfactant effect. The study does not confirm the participation of ATP-dependent potassium channels and cAMP-regulated epithelial chloride channels known as CFTR chloride channels, or nitric oxide involvement in contractile response of smooth muscle to surfactant.By controlling wall thickness and airway diameter, pulmonary surfactant is an important component of airway physiology. Thus, surfactant dysfunction may be included in pathophysiology of asthma, COPD, or other diseases with bronchial obstruction.
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Affiliation(s)
- A Calkovska
- Department of Physiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Slovakia.
| | - B Uhliarova
- Department of Otorhinolaryngology, FD Roosevelt Faculty Hospital, Banska Bystrica, Slovakia.
| | - M Joskova
- Department of Pharmacology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Slovakia.
| | - S Franova
- Department of Pharmacology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Slovakia.
| | - M Kolomaznik
- Department of Physiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Slovakia.
| | - V Calkovsky
- Clinic of Otorhinolaryngology and Head and Neck Surgery, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava and University Hospital Martin, Slovakia.
| | - S Smolarova
- Department of Physiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Slovakia.
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5
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Abstract
While asthma is extremely common, fatal and near fatal asthma is rare and often preventable if there is early recognition of symptom progression and appropriate intervention. In the past decade, asthma mortality has progressively declined in association with the widespread use of inhaled corticosteroids and asthma care plans. Management of life threatening asthma requires patient education to ensure the proper use of medications and to enable the patient to recognize when additional therapy for poorly controlled asthma is required. There is some evidence that suggests that the overly aggressive use of asthma medications when treating a severe exacerbation may contribute to morbidity. Because of the risks of air trapping and barotrauma associated with partial airway obstruction, it is best to avoid mechanical ventilation if possible but when this is used, low tidal volumes, longer exhalation times, and permissive hypercarbia can minimize these risks. There is the promise that a better understanding of asthma immunology and severe asthma "phenotypes" will lead to better prevention and therapy.
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Affiliation(s)
- Bruce K Rubin
- Virginia Commonwealth University Department of Pediatrics and the Children's Hospital of Richmond, Richmond, VA 23298, USA.
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6
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Garcia G, Perez T, Mahut B. [Lung function testing and assessment of distal airways in asthma]. Rev Mal Respir 2009; 26:395-406; quiz 479, 482. [PMID: 19421092 DOI: 10.1016/s0761-8425(09)74044-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Small airways are defined (in humans) as those<2mm in diameter. BACKGROUND They were originally described as the "quiet zone" of the lungs contributing less than 10% of the total resistance to airflow. Pulmonary function tests remain the most used method to assess distal airway flow limitation. VIEWPOINTS However, these tests are limited in adults and also in children because MEF25-75% and FEF50% are highly variable spirometric indices and they depend on vital capacity, which increases with expiratory time in obstructed subjects. There is a need for promising non invasive new tools like the forced oscillation technique to measure resistance. The increased availability of the exhaled fraction of nitric oxide (FeNO) measurement means that this method is accessible and attractive. CONCLUSION The production of nitric oxide (NO) can be assessed by measuring the fraction of NO during a prolonged expiration (FENO) or by estimating other parameters of NO exchange including the alveolar NO concentration (CalvNO) and may provide information about small airway inflammation and assist the optimal control of the disease.
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Affiliation(s)
- G Garcia
- Service d'Explorations fonctionnelles multidisciplinaires, Hôpital Antoine-Béclère, Université Paris-Sud, Assistance Publique-Hôpitaux de Paris, Clamart, France.
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Christmann U, Buechner-Maxwell VA, Witonsky SG, Hite RD. Role of lung surfactant in respiratory disease: current knowledge in large animal medicine. J Vet Intern Med 2009; 23:227-42. [PMID: 19192153 DOI: 10.1111/j.1939-1676.2008.0269.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Lung surfactant is produced by type II alveolar cells as a mixture of phospholipids, surfactant proteins, and neutral lipids. Surfactant lowers alveolar surface tension and is crucial for the prevention of alveolar collapse. In addition, surfactant contributes to smaller airway patency and improves mucociliary clearance. Surfactant-specific proteins are part of the innate immune defense mechanisms of the lung. Lung surfactant alterations have been described in a number of respiratory diseases. Surfactant deficiency (quantitative deficit of surfactant) in premature animals causes neonatal respiratory distress syndrome. Surfactant dysfunction (qualitative changes in surfactant) has been implicated in the pathophysiology of acute respiratory distress syndrome and asthma. Analysis of surfactant from amniotic fluid allows assessment of fetal lung maturity (FLM) in the human fetus and exogenous surfactant replacement therapy is part of the standard care in premature human infants. In contrast to human medicine, use and success of FLM testing or surfactant replacement therapy remain limited in veterinary medicine. Lung surfactant has been studied in large animal models of human disease. However, only a few reports exist on lung surfactant alterations in naturally occurring respiratory disease in large animals. This article gives a general review on the role of lung surfactant in respiratory disease followed by an overview of our current knowledge on surfactant in large animal veterinary medicine.
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Affiliation(s)
- U Christmann
- Department of Large Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Duck Pond Drive, Phase II, Blacksburg, VA 24061, USA.
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Erpenbeck VJ, Krug N, Hohlfeld JM. Therapeutic use of surfactant components in allergic asthma. Naunyn Schmiedebergs Arch Pharmacol 2008; 379:217-24. [PMID: 18854984 DOI: 10.1007/s00210-008-0354-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2008] [Accepted: 09/10/2008] [Indexed: 01/26/2023]
Abstract
Pulmonary surfactant is a complex mixture of lipids and proteins that reduces the surface tension at the air-liquid interface. In addition to its biophysical function, some surfactant components play an important role for the innate and adaptive immunity of the lung. A negative modulation of the surfactant function was observed in allergic asthma leading to the assumption that the therapeutic application of surfactant components might be beneficial in this disease. So far, there are a number of preclinical and already some clinical studies demonstrating various effects of different surfactant components that were administered with preventive or therapeutic aim in allergic asthma. This review summarizes the current knowledge on the possibilities to treat allergic asthma with surfactant components.
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Affiliation(s)
- Veit J Erpenbeck
- Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany.
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9
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Abo M, Kurashima K, Fujimura M, Myou S, Nakao S, Tashiro K, Kobayashi T. Surfactant degradation activity in bronchoalveolar lavage fluid from guinea pigs challenged with antigen. Respirology 2008; 12:828-33. [PMID: 17986110 DOI: 10.1111/j.1440-1843.2007.01179.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND OBJECTIVE Surfactant dysfunction is a characteristic of bronchial asthma, but mechanisms of dysfunction following antigen exposure are not understood. The aim of this study was to examine whether bronchoalveolar lavage fluid (BALF) has surfactant degradation activity after antigen challenge, using an animal model of asthma. METHODS BALF was collected 24 h after a challenge with aerosolized antigen solution in actively sensitized guinea pigs and from non-sensitized control guinea pigs. The surface tension of BALF was measured by pulsating bubble surfactometer. Surfactant activity was expressed as the minimum surface tension of BALF after 5 min of pulsation. BALF was separated into a cellular phospholipid fraction and supernatant, and reconstituted into 'pellet + supernatant' and 'pellet + saline' fractions. RESULTS Surfactant activity of BALF from sensitized antigen-challenged animals was reduced after 4 h of incubation at 37 degrees C but a decrease was not observed in BALF from non-sensitized control animals. The decrease of surfactant activity in BALF from challenged animals was prevented by incubation at 4 degrees C. Disappearance of surfactant activity after incubation at 37 degrees C was observed in the 'pellet + supernatant', but not in the 'pellet + saline' fraction. The decrease of surfactant activity in BALF was also partially suppressed by the secretory phospholipase A2 inhibitor, indoxam, and by a cocktail of protease inhibitors. CONCLUSION Surfactant-degrading activity was present in the supernatant of BALF from antigen-challenged guinea pigs. This activity may be attributed to secretory phospholipase A2 and to proteases present in the antigen-challenged airway.
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Affiliation(s)
- Miki Abo
- Department of Respiratory and Hematology Medicine, Cellular Transplantation Biology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan.
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Garcia G, Perez T, Didier A. [Lung function tests in refractory asthma]. Presse Med 2007; 37:143-54. [PMID: 18036771 DOI: 10.1016/j.lpm.2007.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Accepted: 10/10/2007] [Indexed: 11/27/2022] Open
Abstract
Obstructive airway disorders and bronchial hyperreactivity are part of the definition of asthma. Lung function tests (LFT) are therefore essential in the diagnosis and follow-up of patients with asthma. Maximum forced expiratory volume in one second (FEV1) is the essential functional indicator of severity and reversibility, according to the Global Initiative for Asthma (Gina). FEV1 has some limitations: it is poorly correlated with dyspnea, symptom control, and lung distention. In severe asthma, FEV1 is the only functional indicator included in the diagnostic criteria. It is one minor criterion among 2 major and 7 minor criteria. Other indicators measured during standard LFT and new functional indicators not yet sufficiently validated should provide important supplementary information to help to characterize the different clinical phenotypes and the pathophysiologic mechanisms involved in refractory asthma.
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Affiliation(s)
- Gilles Garcia
- Service des explorations fonctionnelles multidisciplinaires, AP-HP, Hôpital Antoine Béclère, Université Paris-Sud, F-92140 Clamart, France.
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Nag K, Hillier A, Parsons K, Garcia MF. Interactions of serum with lung surfactant extract in the bronchiolar and alveolar airway models. Respir Physiol Neurobiol 2007; 157:411-24. [PMID: 17350899 DOI: 10.1016/j.resp.2007.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 01/24/2007] [Accepted: 02/02/2007] [Indexed: 11/25/2022]
Abstract
Lung surfactant (LS) a lipid-protein mixture is secreted by type-II pneumocytes and prevents alveolar collapse as well as maintains upper airway patency. In certain lung pathophysiology dysfunction of the LS occurs due to leakage of serum derived materials interacting with surfactant at the respiratory air-water interface. Bovine lipid extract surfactant (BLES) with and without foetal calf serum (FCS) were studied as models of bronchiolar airway patency using a capillary surfactometer, and in alveolar (terminal) airway using adsorbed Langmuir films in a surface balance. About 5 wt.% of serum was found to maximally decrease airway patency of BLES by 90%, as well as the surface films ability to reach low surface tension below 25 mN/m. In fact, FCS was found to be about 200-fold more potent inhibitor of the surfactant extract compared to a major serum component, albumin. Also serum but not albumin significantly reduced the gel-phase structures found in BLES films under compression at low amounts (5-10 wt.%), and eventually abolished these organized structures as imaged by fluorescence and atomic force microscopy. This fact suggests that serum caused complete molecular re-organization of the surfactant lipids in films at an air-water interface, and the ability of such films to reduce surface tension or maintain airway patency. The study may provide a novel structure-function disruption model for lung surfactant inactivation in the airways in pathophysiology.
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Affiliation(s)
- Kaushik Nag
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland, Canada A1B 3X9.
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12
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Kwatia MA, Doyle CB, Cho W, Enhorning G, Ackerman SJ. Combined activities of secretory phospholipases and eosinophil lysophospholipases induce pulmonary surfactant dysfunction by phospholipid hydrolysis. J Allergy Clin Immunol 2007; 119:838-47. [PMID: 17321580 DOI: 10.1016/j.jaci.2006.12.614] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2006] [Revised: 11/29/2006] [Accepted: 12/11/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND Surfactant dysfunction is implicated in small airway closure in asthma. Increased activity of secretory phospholipase A(2) (sPLA(2)) in the airways is associated with asthma exacerbations. Phosphatidylcholine, the principal component of pulmonary surfactant that maintains small airway patency, is hydrolyzed by sPLA(2). The lysophosphatidylcholine product is the substrate for eosinophil lysophospholipases. OBJECTIVE To determine whether surfactant phospholipid hydrolysis by the combined activities of sPLA(2)s and eosinophil lysophospholipases induces surfactant dysfunction. METHODS The effect of these enzymes on surfactant function was determined by capillary surfactometry. Thin layer chromatography was used to correlate enzyme-induced changes in surfactant phospholipid composition and function. Phosphatidylcholine and its hydrolytic products were measured by using mass spectrometry. RESULTS Eosinophils express a 25-kd lysophospholipase and group IIA sPLA(2). Phospholipase A(2) alone induced only a small decrease in surfactant function, and 25-kd lysophospholipase alone degraded lysophosphatidylcholine but had no effect on surfactant function. The combined actions of sPLA(2) and lysophospholipase produced dose-dependent and time-dependent losses of surfactant function, concomitant with hydrolysis of phosphatidylcholine and lysophosphatidylcholine. Lysates of AML14.3D10 eosinophils induced surfactant dysfunction, indicating these cells express all the necessary lipolytic activities. In contrast, lysates of blood eosinophils required exogenous phospholipase A(2) to induce maximal surfactant dysfunction. CONCLUSION The combined activities of sPLA(2)s and eosinophil lysophospholipases are necessary to degrade surfactant phospholipids sufficiently to induce functional losses in surfactant activity as reported in asthma. CLINICAL IMPLICATIONS The phospholipases and lysophospholipases expressed by eosinophils or other airway cells may represent novel therapeutic targets for blocking surfactant degradation, dysfunction, and peripheral airway closure in asthma.
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Affiliation(s)
- Mark A Kwatia
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607-7170, USA
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Wagers SS, Norton RJ, Rinaldi LM, Bates JHT, Sobel BE, Irvin CG. Extravascular fibrin, plasminogen activator, plasminogen activator inhibitors, and airway hyperresponsiveness. J Clin Invest 2004; 114:104-11. [PMID: 15232617 PMCID: PMC437962 DOI: 10.1172/jci19569] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2003] [Accepted: 04/20/2004] [Indexed: 12/18/2022] Open
Abstract
Mechanisms underlying airway hyperresponsiveness are not yet fully elucidated. One of the manifestations of airway inflammation is leakage of diverse plasma proteins into the airway lumen. They include fibrinogen and thrombin. Thrombin cleaves fibrinogen to form fibrin, a major component of thrombi. Fibrin inactivates surfactant. Surfactant on the airway surface maintains airway patency by lowering surface tension. In this study, immunohistochemically detected fibrin was seen along the luminal surface of distal airways in a patient who died of status asthmaticus and in mice with induced allergic airway inflammation. In addition, we observed altered airway fibrinolytic system protein balance consistent with promotion of fibrin deposition in mice with allergic airway inflammation. The airways of mice were exposed to aerosolized fibrinogen, thrombin, or to fibrinogen followed by thrombin. Only fibrinogen followed by thrombin resulted in airway hyperresponsiveness compared with controls. An aerosolized fibrinolytic agent, tissue-type plasminogen activator, significantly diminished airway hyperresponsiveness in mice with allergic airway inflammation. These results are consistent with the hypothesis that leakage of fibrinogen and thrombin and their accumulation on the airway surface can contribute to the pathogenesis of airway hyperresponsiveness.
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Affiliation(s)
- Scott S Wagers
- Vermont Lung Center, Department of Medicine, University of Vermont College of Medicine, Burlington, Vermont 05405-0075, USA.
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14
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Wagers SS, Norton RJ, Rinaldi LM, Bates JH, Sobel BE, Irvin CG. Extravascular fibrin, plasminogen activator, plasminogen activator inhibitors, and airway hyperresponsiveness. J Clin Invest 2004. [DOI: 10.1172/jci200419569] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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15
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Hohlfeld JM, Schmiedl A, Erpenbeck VJ, Venge P, Krug N. Eosinophil cationic protein alters pulmonary surfactant structure and function in asthma. J Allergy Clin Immunol 2004; 113:496-502. [PMID: 15007353 DOI: 10.1016/j.jaci.2003.12.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Impaired surfactant function has been demonstrated in patients with asthma. Inhibitory proteins originating from plasma or inflammatory mediators are good candidates to contribute to this dysfunction. Eosinophils are potent effector cells in asthma, which, on activation, release inflammatory mediators, especially reactive granula proteins such as eosinophil cationic protein (ECP). OBJECTIVE Because the potential role of ECP in the inhibition of surfactant function is not known, we tested the hypothesis of whether ECP levels in bronchoalveolar lavage fluid (BALF) of patients with asthma after segmental allergen provocation correlate to surfactant dysfunction. Furthermore, we tested the effect of purified ECP on surfactant function and structure in vitro. METHODS Surfactant isolated from BALF of asthmatic patients was assessed for biophysical function with the Pulsating Bubble Surfactometer and the Capillary Surfactometer and correlated to ECP levels. Purified ECP and plasma proteins at various concentrations were incubated with natural surfactant. Surfactant function was studied with the Capillary Surfactometer, and surfactant structure was determined by electron microscopy. RESULTS ECP is elevated in BALF from patients with asthma after allergen challenge compared with baseline. ECP levels after allergen challenge correlate well to surfactant dysfunction. In vitro, ECP induces a concentration-dependent inhibition of surfactant function that can be inhibited by antibodies against ECP. ECP is more potent compared with albumin or fibrinogen. Finally, ECP induces severe ultrastructural changes to surfactant vesicles that are more pronounced than changes induced by either fibrinogen or albumin. CONCLUSIONS ECP contributes to surfactant dysfunction in asthma, which in turn could lead to airway obstruction.
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Affiliation(s)
- Jens M Hohlfeld
- Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany
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16
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Chang AB, Hills Y, Harrhy VA, Hills BA. Agreement in surfactant measurements of sputum induced with hypertonic and normal saline. Respirology 2003; 8:41-4. [PMID: 12856740 DOI: 10.1046/j.1440-1843.2003.00421.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE The contribution of surfactant to the airway epithelial barrier is increasingly being recognized. Dipalmitoyl phosphatidycholine (DPPC), the major constituent of surfactant, is affected by lung injury. Hypertonic saline-induced sputum is a convenient and reliable method of assessing airway cells and mediators. However, the influence of hypertonic saline on DPPC content of sputum is unknown. In this study the level of DPPC in induced sputum obtained using hypertonic saline is examined and compared with that obtained using normal saline. METHODOLOGY Sputum was induced on two occasions using nebulized hypertonic saline and normal saline, in 15 well non-smoking adults, in random order on different days. DPPC content (microg/mL of sputum) was measured using a standard spectrophotometric method. RESULTS The mean of log10 DPPC level in sputum obtained using hypertonic saline was 1.88 microg/mL sputum (95% CI 1.53, 2.13) and that obtained using normal saline was 1.83 (95% CI 1.62, 2.14). The mean difference of the two methods was -0.03 (95% CI -0.27, 0.33). Bland and Altman plot showed an equal distribution around the mean and all points were within the mean +/- 2 SD. CONCLUSION We conclude that DPPC concentration of sputum can be easily measured in induced sputum and that the use of hypertonic saline does not influence the DPPC levels.
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Affiliation(s)
- Anne B Chang
- Department of Respiratory Medicine, Royal Children's Hospital, Brisbane and University of Queensland, Australia.
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17
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Chang AB, Gibson PG, Masters IB, Dash P, Hills BA. The relationship between inflammation and dipalmitoyl phosphatidycholine in induced sputum of children with asthma. J Asthma 2003; 40:63-70. [PMID: 12699213 DOI: 10.1081/jas-120017208] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Animal studies have shown elevated surfactant production in response to lung injury. In human airways, the contribution of surfactant to the airway epithelial barrier and importance of eosinophilic inflammation is increasingly appreciated. The relationship between blood and sputum inflammatory indices of childhood asthma to surfactant levels is unknown. In this study we hypothesized that the degree of inflammation influences the level of dipalmitoyl phosphatidycholine (DPPC) in airways of children with asthma. METHODS Sixteen children with asthma (ages 5.5-16 years) underwent venipuncture, skin prick test, spirometry, hypertonic saline challenge, and induced sputum during a nonacute phase. Sputum (sp) and blood (se) markers of inflammation (eosinophils, neutrophils, eosinophilic cationic protein [ECP]), were related to sputum DPPC levels and several markers of asthma severity (airway hyperresponsiveness, quality of life, FEV1). RESULTS On multiple regression, sp-DPPC significantly correlated to sp-ECP (r=0.53, P=0.0048). Se-ECP, se-Eo, sp-eosinophils, sp-neutrophils, se-neutrophils, and inhaled steroids dose did not significantly influence sp-DPPC. Exposure to smoke did not influence inflammatory markers. FEV1 and quality of life data did not relate to any blood or sputum variable. A significant association between AHR and se-eosinophils, but not between AHR and se-ECP, sp-eosinophils, or sp-ECP was found. CONCLUSION Elevated DPPC levels occur in the presence of chronic eosinophilic inflammation in airways of children with stable asthma. Whether this represents an inherent lung mechanism for epithelial protection remains to be elucidated.
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Affiliation(s)
- Anne B Chang
- Flinders University Northern Territory Clinical School, Alice Springs Hospital, Northern Territory, Australia.
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18
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Haczku A, Atochina EN, Tomer Y, Cao Y, Campbell C, Scanlon ST, Russo SJ, Enhorning G, Beers MF. The late asthmatic response is linked with increased surface tension and reduced surfactant protein B in mice. Am J Physiol Lung Cell Mol Physiol 2002; 283:L755-65. [PMID: 12225952 DOI: 10.1152/ajplung.00062.2002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pulmonary surfactant dysfunction may significantly contribute to small airway obstruction during the asthmatic response, but neither its exact role nor its regulation is clear. Surfactant function and composition was studied in an Aspergillus fumigatus (Af)-induced late-phase allergic airway response in sensitized BALB/c mice. The peak of Af-induced airway hyperresponsiveness in sensitized and challenged mice 24 h after allergen provocation coincided with a significant fall in surface activity of the pulmonary surfactant. The underlying changes included time-dependent elaboration of eotaxin and IL-5 followed by eosinophil influx into the airways. The height of airway inflammation and hyperresponsiveness was preceded by release of IL-4 and marked reductions in surfactant protein (SP)-B, a hydrophobic surfactant protein responsible for maintaining low surface tension of the lining fluid of distal air spaces. Furthermore, intratracheal administration of IL-4 significantly inhibited SP-B, indicating a regulatory role of this cytokine in the surfactant biophysical changes. Thus surfactant dysfunction induced by an IL-4-driven SP-B deficiency after allergen provocation may be an important part of the late asthmatic airway response.
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Affiliation(s)
- Angela Haczku
- Pulmonary, Allergy and Critical Care Division, Department of Medicine, University of Pennsylvania Medical School, Philadelphia 19104, USA.
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19
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Devendra G, Spragg RG. Lung surfactant in subacute pulmonary disease. Respir Res 2002; 3:19. [PMID: 11980588 PMCID: PMC107848 DOI: 10.1186/rr168] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2001] [Revised: 02/18/2002] [Accepted: 02/20/2002] [Indexed: 12/04/2022] Open
Abstract
Pulmonary surfactant is a surface active material composed of both lipids and proteins that is produced by alveolar type II pneumocytes. Abnormalities of surfactant in the immature lung or in the acutely inflamed mature lung are well described. However, in a variety of subacute diseases of the mature lung, abnormalities of lung surfactant may also be of importance. These diseases include chronic obstructive pulmonary disease, asthma, cystic fibrosis, interstitial lung disease, pneumonia, and alveolar proteinosis. Understanding of the mechanisms that disturb the lung surfactant system may lead to novel rational therapies for these diseases.
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Affiliation(s)
| | - Roger G Spragg
- San Diego Veterans Affairs Medical Center, San Diego, California, USA
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20
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Hohlfeld JM. The role of surfactant in asthma. Respir Res 2002; 3:4. [PMID: 11806839 PMCID: PMC64815 DOI: 10.1186/rr176] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2001] [Revised: 08/13/2001] [Accepted: 08/31/2001] [Indexed: 01/07/2023] Open
Abstract
Pulmonary surfactant is a unique mixture of lipids and surfactant-specific proteins that covers the entire alveolar surface of the lungs. Surfactant is not restricted to the alveolar compartment; it also reaches terminal conducting airways and is present in upper airway secretions. While the role of surfactant in the alveolar compartment has been intensively elucidated both in health and disease states, the possible role of surfactant in the airways requires further research. This review summarizes the current knowledge on surfactant functions regarding the airway compartment and highlights the impact of various surfactant components on allergic inflammation in asthma.
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Affiliation(s)
- Jens M Hohlfeld
- Department of Respiratory Medicine, Hannover Medical School, Fraunhofer Institute of Toxicology and Aerosol Research, Hannover, Germany.
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21
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Abstract
There are few therapies for which the cumulative evidence of benefit is as much as that for surfactant therapy for RDS in premature infants. Exogenous surfactant therapy does seem to be beneficial for a number of non-RDS disorders. Although there are some trials supporting its use in MAS and ALI-ARDS, there are only a few small prospective, randomized, controlled trials supporting surfactant use in non-RDS disorders. Use of surfactant therapy for any disorder other than RDS must be considered "off the shelf" and experimental. Much work remains to be done to address the role of surfactant therapy in the myriad disorders discussed. Of import for each of the disorders is addressing the optimum type of surfactant to use, and the appropriate dose, method of delivery, and duration of treatment regimens.
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Affiliation(s)
- T E Wiswell
- Department of Pediatrics, State University of New York at Stony Brook, Stony Brook, New York, USA.
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22
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Wang JY, Shieh CC, Yu CK, Lei HY. Allergen-induced bronchial inflammation is associated with decreased levels of surfactant proteins A and D in a murine model of asthma. Clin Exp Allergy 2001; 31:652-62. [PMID: 11359435 DOI: 10.1046/j.1365-2222.2001.01031.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Increasing evidence suggests that pulmonary surfactant protein A (SP-A) and D (SP-D) participate in the lung defence against pathogens. However, the role of surfactant proteins in the pathogenesis of allergen-induced airway inflammation has not been elucidated. In this study we examined the levels and distributions of SP-A and SP-D in a dust mite (Dermatophagoides pteronyssinus, Der p) allergen-induced murine model of asthma. METHODS The concentration of SP-A and SP-D in the bronchoalveolar lavage fluid (BALF) and the distribution of surfactant proteins in the lung were assayed by ELISA and immunohistochemistry methods, respectively. The effect of surfactant proteins on allergen-induced pulmonary lymphocyte proliferation was also studied. RESULTS We demonstrated that there were marked reductions of SP-A and SP-D levels in the BALF of Der p-sensitized BALB/c mice at 48-72 h after allergen challenge (AC). Both purified SP-A and SP-D were able to suppress, in a dose dependent manner, Der p-stimulated intrapulmonary lymphocyte proliferation of naïve mice with saline or allergen challenge, or of Der p-sensitized mice with saline challenge. On the contrary, this suppressive effect was mild (< 9%) on lymphocytes from sensitized mice after AC. CONCLUSION These results indicated the involvement of pulmonary surfactant proteins in the allergic bronchial inflammation of sensitized mice.
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Affiliation(s)
- J Y Wang
- Division of Clinical Immunology, Departments of Paediatrics, and Microbiology and Immunology, College of Medicine, National Cheng-Kung University, Tainan, Taiwan, Republic of China.
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23
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Cheng G, Ueda T, Sugiyama K, Toda M, Fukuda T. Compositional and functional changes of pulmonary surfactant in a guinea-pig model of chronic asthma. Respir Med 2001; 95:180-6. [PMID: 11266234 DOI: 10.1053/rmed.2000.1012] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Recent studies have found that severe surfactant dysfunction occurs during an asthma attack, but the changes in surfactant in a guinea-pig model of chronic asthma have not been studied. We therefore analysed the surfactant recovered from guinea-pigs after repeated inhalation of ovalbumin to see if the surfactant recovered from chronic asthmatic lungs would be intrinsically altered. Guinea pigs immunized through repeated inhalation of aerosolized ovalbumin (OA) were exposed to the antigen once a week for a month. Twenty-four hours after the last challenge the alveolar wash was recovered. We calculated saturated phosphatidylcholine (Sat-PC) and total protein (TP) pool sizes in alveolar spaces. Surfactant subtype conversion of large aggregate surfactant (LA) to small aggregate surfactant was studied in vitro by means of the surface area cycling technique. The phospholipid composition of LA was analysed by thin layer chromatography and the surface activity of LA was also determined. We found decreased surfactant pool sizes, decreased ratio of Sat-PC to TP in alveolar lavages in asthma groups, and surface activity of the surfactant recovered from asthmatic lungs to be inferior to that of the controls. Accelerated surfactant subtype conversion in vitro was also noted in the lungs of asthmatic animal models. In addition, the changes in phospholipid compositions which were similar to the pattern of acute lung injury suggested that alveolar inflammation might be involved in the pathogenesis of chronic asthma. These results indicate that surfactant is intrinsically abnormal in chronically asthmatic lungs.
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Affiliation(s)
- G Cheng
- Department of Pulmonary Medicine and Clinical Immunology, Dokkyo University School of Medicine, Japan
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24
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Wright SM, Hockey PM, Enhorning G, Strong P, Reid KB, Holgate ST, Djukanovic R, Postle AD. Altered airway surfactant phospholipid composition and reduced lung function in asthma. J Appl Physiol (1985) 2000; 89:1283-92. [PMID: 11007560 DOI: 10.1152/jappl.2000.89.4.1283] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pulmonary surfactant in bronchoalveolar lavage fluid (BALF) and induced sputum from adults with stable asthma (n = 36) and healthy controls (n = 12) was analyzed for phospholipid and protein compositions and function. Asthmatic subjects were graded as mild, moderate, or severe. Phospholipid compositions of BALF and sputum from control subjects were similar and characteristic of surfactant. For asthmatic subjects, the proportion of dipalmitoyl phosphatidylcholine (16:0/16:0PC), the major phospholipid in surfactant, decreased in sputum (P < 0.05) but not in BALF. In BALF, mole percent 16:0/16:0PC correlated with surfactant function measured in a capillary surfactometer, and sputum mole percent 16:0/16:0PC correlated with lung function (forced expiratory volume in 1 s). Neither surfactant protein A nor total protein concentration in either BALF or sputum was altered in asthma. These results suggest altered phospholipid composition and function of airway (sputum) but not alveolar (BALF) surfactant in stable asthma. Such underlying surfactant dysfunction may predispose asthmatic subjects to further surfactant inhibition by proteins or aeroallergens in acute asthma episodes and contribute to airway closure in asthma. Consequently, administration of an appropriate therapeutic surfactant could provide clinical benefit in asthma.
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Affiliation(s)
- S M Wright
- Department of Child Health, University of Southampton, Southampton SO16 6YD, United Kingdom
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25
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in 't Veen JC, Beekman AJ, Bel EH, Sterk PJ. Recurrent exacerbations in severe asthma are associated with enhanced airway closure during stable episodes. Am J Respir Crit Care Med 2000; 161:1902-6. [PMID: 10852764 DOI: 10.1164/ajrccm.161.6.9906075] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Excessive airway narrowing is a cardinal feature of asthma, and results in closure of airways. Therefore, asthmatic patients in whom airway closure occurs relatively early during expiration might be prone to severe asthma attacks. To test this hypothesis, we compared closing volume (CV) and closing capacity (CC) in a group of asthmatic patients with recurrent exacerbations (more than two exacerbations in the previous year; difficult-to-control asthma), consisting of 11 males and two females, aged 20 to 51 yr, with those in a group of equally severely asthmatic controls without recurrent exacerbations (stable asthma) consisting of 13 males and two females aged 18 to 52 yr. Both groups used equivalent doses of inhaled corticosteroids and were matched for sex, age, atopy, postbronchodilator FEV(1), and provocative concentration of methacholine causing a 20% decrease in FEV(1). They were studied during a clinically stable period of their disease. The patients inhaled 400 microg salbutamol via a spacer device, after which TLC and RV were measured by multibreath helium equilibration, together with the slope of Phase 3 (dN(2)), CV, and CC, by single-breath nitrogen washout. CV and CC were expressed as ratios of VC and TLC, respectively, and all data are presented as % predicted (mean +/- SEM). There was no difference in TLC in patients with difficult-to-control asthma and those with stable asthma (106.7 +/- 4.0% predicted versus 101.7 +/- 4.3% predicted, p = 0.40), RV (113.1 +/- 7.8% predicted versus 100.9 +/- 7.1% predicted, p = 0.26), or dN(2) (142.7 +/- 16.3% predicted versus 116.0 +/- 20.2% predicted, p = 0.23). In contrast, CV and CC were increased in the patients with difficult-to-control asthma as compared with the group with stable asthma (CV: 159.5 +/- 26.8% predicted versus 98.8 +/- 12.5% predicted, p = 0.024; CC: 114.0 +/- 6.4% predicted versus 99.9 +/- 3. 6% predicted, p = 0.030). These findings show that asthmatic individuals with recurrent exacerbations have increased CV and CC as compared with equally severely asthmatic but stable controls, even after bronchodilation during well-controlled episodes. The findings imply that airway closure at relatively high lung volumes under clinically stable conditions might be a risk factor for severe exacerbations in asthmatic patients.
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Affiliation(s)
- J C in 't Veen
- Lung Function Laboratory, Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands
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26
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Heeley EL, Hohlfeld JM, Krug N, Postle AD. Phospholipid molecular species of bronchoalveolar lavage fluid after local allergen challenge in asthma. Am J Physiol Lung Cell Mol Physiol 2000; 278:L305-11. [PMID: 10666114 DOI: 10.1152/ajplung.2000.278.2.l305] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Electrospray ionization mass spectrometry was used to quantify phosphatidylcholine (PC) and phosphatidylglycerol (PG) molecular species in bronchoalveolar lavage fluid (BALF) from control and mild asthmatic subjects after local allergen challenge. BALF was obtained from 5 control and 13 asthmatic subjects before and 24 h after segmental allergen and saline challenge. There were no differences in the ratio of total PC to total PG or in the molecular species composition of PC or PG between the asthmatic and control groups under basal conditions. Allergen challenge in asthmatic but not in control volunteers caused a significant increase in the PC-to-PG ratio because of increased concentrations of PC species containing linoleic acid (16:0/18:2 PC, 18:0/18:2 PC, and 18:1/18:2 PC). These molecular species were characteristic of plasma PC analyzed from the same subjects, strongly suggesting that the altered PC composition in BALF in asthmatic subjects after allergen challenge was due to infiltration of plasma lipoprotein, not to catabolism of surfactant phospholipid. Interactions between surfactant and lipoprotein infiltrate may contribute to surfactant dysfunction and potentiate disease severity in asthma.
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Affiliation(s)
- E L Heeley
- Child Health, University of Southampton, Southampton SO16 6YD, United Kingdom
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27
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Banerjee R, Puniyani RR. Exogenous surfactant therapy and mucus rheology in chronic obstructive airway diseases. J Biomater Appl 2000; 14:243-72. [PMID: 10656543 DOI: 10.1177/088532820001400304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Exogenous surfactant is a specialized biomaterial used for substitution of the lipoprotein mixture normally present in the lungs-pulmonary surfactant. Respiratory Distress Syndrome is a disease of preterm infants mainly caused by pulmonary immaturity as evidenced by a deficiency of mature lung surfactant. Pulmonary surfactant is known to stabilize small alveoli and prevent them from collapsing during expiration. However, apart from alveoli, surfactant also lines the narrow conducting airways of the tracheobronchial tree. This paper reviews the role of this surfactant in the airways and its effect on mucus rheology and mucociliary clearance. Its potential role as a therapeutic biomaterial in chronic obstructive airway diseases, namely asthma, chronic bronchitis, and respiratory manifestations of cystic fibrosis, are discussed. This paper also attempts to elucidate the exact steps in the pathogenic pathway of these diseases which could be reversed by supplementation of exogenous surfactant formulations. It is shown that there is great potential for the use of present day surfactants (which are actually formulated for use in Respiratory Disease Syndrome) as therapy in the aforementioned diseases of altered mucus viscoelasticity and mucociliary clearance. However, for improved effectiveness, specific surfactant formulations satisfying certain specific criteria should be tailor-made for the clinical condition for which they are intended. The properties required to be fulfilled by the optimal exogenous surfactant in each of the above clinical conditions are enumerated in this paper.
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Affiliation(s)
- R Banerjee
- School of Biomedical Engineering, Indian Institute of Technology, Powai, Bombay
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28
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Jarjour NN, Enhorning G. Antigen-induced airway inflammation in atopic subjects generates dysfunction of pulmonary surfactant. Am J Respir Crit Care Med 1999; 160:336-41. [PMID: 10390421 DOI: 10.1164/ajrccm.160.1.9806155] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
If pulmonary surfactant develops a dysfunction, its ability to maintain patency of narrow conducting airways diminishes, which is likely to cause an increased airway resistance. We hypothesized that antigen challenge will cause inflammation in the conducting airways and that this will cause a surfactant dysfunction. Twenty atopic patients underwent bronchoalveolar lavage (BAL) 5 min and 48 h after challenge with antigen in one segment and with saline solution in another. BAL fluid (BALF) cell count, differential, and proteins were determined. Surfactant function was studied with a capillary surfactometer (CS), an instrument specifically designed to evaluate surfactant's ability to maintain patency. Eosinophils increased 80-fold 48 h after antigen challenge and total protein increased from 84 to 241 micrograms/ml (median values). BALF surfactant lost part of its ability to maintain openness of the capillary, from 68.8% to 14.0% (p < 0.05). Protein concentration negatively correlated with percent openness (r = -0.62, p = 0.005). We conclude that the antigen challenge resulted in an inflammatory reaction that caused pulmonary surfactant to lose some of its ability to maintain airway patency and speculate that surfactant dysfunction is probably an important factor contributing to increased airway obstruction in allergen-induced exacerbation of asthma.
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Affiliation(s)
- N N Jarjour
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Wisconsin School of Medicine and Perinatal Center, Madison, WI 53792, USA.
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29
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Hohlfeld JM, Ahlf K, Enhorning G, Balke K, Erpenbeck VJ, Petschallies J, Hoymann HG, Fabel H, Krug N. Dysfunction of pulmonary surfactant in asthmatics after segmental allergen challenge. Am J Respir Crit Care Med 1999; 159:1803-9. [PMID: 10351922 DOI: 10.1164/ajrccm.159.6.9806145] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Increased airway resistance in asthma may be partly due to poor function of pulmonary surfactant. This study investigated the inflammatory changes of bronchoalveolar lavage fluid (BALF) and the performance of BALF surfactant in healthy control subjects (n = 9) and patients with mild allergic asthma (n = 15) before and after segmental challenge. BALF was obtained for baseline values, and 24 h after challenge with saline solution in one lung segment and with allergen in another. Cell counts, phospholipid and protein concentrations, and ratios of small to large surfactant aggregates (SA/LA) were analyzed. Surface tension was determined with a pulsating bubble surfactometer, and the ability of the BALF surfactant to maintain airway patency was assessed with a capillary surfactometer. Baseline values of control subjects and asthmatics were not different. Challenge with saline and antigen raised total inflammatory cells in both control subjects and asthmatics. Allergen challenge of asthmatics, but not of healthy volunteers, significantly increased eosinophils, proteins, SA/ LA, and surface tension at minimum bubble size, and diminished the time the capillary tube is open. In conclusion, allergen challenge in asthmatics induced surfactant dysfunction, probably mainly because of inhibiting proteins. During an asthma attack, narrow conducting airways may become blocked, which might contribute to an increased airway resistance.
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Affiliation(s)
- J M Hohlfeld
- Department of Respiratory Medicine, Hannover Medical School, Hannover; Fraunhofer Institute of Toxicology and Aerosol Research, Hannover, Germany
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30
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Nyce JW. Insight into adenosine receptor function using antisense and gene-knockout approaches. Trends Pharmacol Sci 1999; 20:79-83. [PMID: 10101969 DOI: 10.1016/s0165-6147(99)01305-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The extensive role of adenosine in discriminating input from the extracellular environment is effected through a series of cell membrane-spanning proteins--the adenosine A1, A2A, A2B and A3 receptors. New genetic and epigenetic tools have emerged that facilitate the elucidation of the function of these receptors with greater specificity than is generally possible with traditional antagonist drugs. These tools include antisense oligonucleotides (epigenetic) and gene 'knockin' and 'knockout' mice (genetic) and are discussed in this article by Jonathan Nyce.
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Affiliation(s)
- J W Nyce
- Department of Molecular Pharmacology and Therapeutics, EpiGenesis Pharmaceuticals, Princeton, NJ 08543, USA
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31
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Wang JY, Shieh CC, You PF, Lei HY, Reid KB. Inhibitory effect of pulmonary surfactant proteins A and D on allergen-induced lymphocyte proliferation and histamine release in children with asthma. Am J Respir Crit Care Med 1998; 158:510-8. [PMID: 9700129 DOI: 10.1164/ajrccm.158.2.9709111] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The role of pulmonary surfactant proteins in the pathogenesis of airway inflammation and the impact on asthma has not been elucidated. This study was designed to examine the effect of surfactant proteins A (SP-A) and D (SP-D) on phytohemagglutinin- (PHA) and mite allergen Dermatophagoides pteronyssinus (Der p)-induced histamine release and the proliferation of peripheral blood mononuclear cells (PBMC) in children with asthma in stable condition (n = 21), asthmatic children during acute attacks (n = 9), and age-matched control subjects (n = 7). The results show that SP-A and SP-D were able to reduce the incorporation of [3H]thymidine into PBMC in a dose-dependent manner. In addition to the intact, native SP-A and SP-D proteins, a recombinant peptide composed of the neck and carbohydrate recognition domain (CRD) of SP-D [SP-D(N/CRD)] was also found to have the same suppressive effect on lymphocyte proliferation. This effect was abolished by the presence of 100 mM mannose (for SP-A) or maltose (for SP-D) in the culture medium, which suggested that the CRD regions of SP-A and SP-D may interact with the carbohydrate structures on the surface molecules of lymphocytes. The inhibitory effects of surfactant proteins on PHA- and Der p-stimulated lymphocyte responses were observed in stable asthmatic children and age-matched control subjects, while only a mild suppression (< 25%) was seen in activated lymphocytes derived from asthmatic children with acute attacks. SP-A and SP-D were also found to inhibit allergen-induced histamine release, in a dose-dependent manner, in the diluted whole blood of asthmatic children. We conclude that both SP-A and SP-D can inhibit histamine release in the early phase of allergen provocation and suppress lymphocyte proliferation in the late phase of bronchial inflammation, the two essential steps in the development of asthmatic symptoms. It appears that SP-A and SP-D may be protective against the pathogenesis of asthma.
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Affiliation(s)
- J Y Wang
- Departments of Pediatrics, and Microbiology and Immunology, College of Medicine, National Cheng-Kung University, Tainan, Taiwan
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