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Abstract
Pulmonary surfactant is a critical component of lung function in healthy individuals. It functions in part by lowering surface tension in the alveoli, thereby allowing for breathing with minimal effort. The prevailing thinking is that low surface tension is attained by a compression-driven squeeze-out of unsaturated phospholipids during exhalation, forming a film enriched in saturated phospholipids that achieves surface tensions close to zero. A thorough review of past and recent literature suggests that the compression-driven squeeze-out mechanism may be erroneous. Here, we posit that a surfactant film enriched in saturated lipids is formed shortly after birth by an adsorption-driven sorting process and that its composition does not change during normal breathing. We provide biophysical evidence for the rapid formation of an enriched film at high surfactant concentrations, facilitated by adsorption structures containing hydrophobic surfactant proteins. We examine biophysical evidence for and against the compression-driven squeeze-out mechanism and propose a new model for surfactant function. The proposed model is tested against existing physiological and pathophysiological evidence in neonatal and adult lungs, leading to ideas for biophysical research, that should be addressed to establish the physiological relevance of this new perspective on the function of the mighty thin film that surfactant provides.
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Affiliation(s)
- Fred Possmayer
- Department of Biochemistry, Western University, London, Ontario N6A 3K7, Canada
- Department of Obstetrics/Gynaecology, Western University, London, Ontario N6A 3K7, Canada
| | - Yi Y Zuo
- Department of Mechanical Engineering, University of Hawaii at Manon, Honolulu, Hawaii 96822, United States
- Department of Pediatrics, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96826, United States
| | - Ruud A W Veldhuizen
- Department of Physiology & Pharmacology, Western University, London, Ontario N6A 5C1, Canada
- Department of Medicine, Western University, London, Ontario N6A 3K7, Canada
- Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
| | - Nils O Petersen
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Department of Chemistry, Western University, London, Ontario N6A 5B7, Canada
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2
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Moya F, Curstedt T, Johansson J, Sweet D. Synthetic surfactants. Semin Fetal Neonatal Med 2023; 28:101503. [PMID: 38036308 DOI: 10.1016/j.siny.2023.101503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Affiliation(s)
- Fernando Moya
- Division of Wilmington Pediatric Subspecialties, Department of Pediatrics, UNC School of Medicine, USA
| | - Tore Curstedt
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Jan Johansson
- Dept of Biosciences and Nutrition, Karolinska Institutet, Neo, 141 83, Huddinge Sweden
| | - David Sweet
- Regional Neonatal Unit, Royal Maternity Hospital, Grosvenor Road, Belfast, UK.
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3
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A recipe for a good clinical pulmonary surfactant. Biomed J 2022; 45:615-628. [PMID: 35272060 PMCID: PMC9486245 DOI: 10.1016/j.bj.2022.03.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 12/11/2022] Open
Abstract
The lives of thousands premature babies have been saved along the last thirty years thanks to the establishment and consolidation of pulmonary surfactant replacement therapies (SRT). It took some time to close the gap between the identification of the biophysical and molecular causes of the high mortality associated with respiratory distress syndrome in very premature babies and the development of a proper therapy. Closing the gap required the elucidation of some key questions defining the structure–function relationships in surfactant as well as the particular role of the different molecular components assembled into the surfactant system. On the other hand, the application of SRT as part of treatments targeting other devastating respiratory pathologies, in babies and adults, is depending on further extensive research still required before enough amounts of good humanized clinical surfactants will be available. This review summarizes our current concepts on the compositional and structural determinants defining pulmonary surfactant activity, the principles behind the development of efficient natural animal-derived or recombinant or synthetic therapeutic surfactants, as well as a the most promising lines of research that are already opening new perspectives in the application of tailored surfactant therapies to treat important yet unresolved respiratory pathologies.
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4
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Wong BH, Mei D, Chua GL, Galam DL, Wenk MR, Torta F, Silver DL. The lipid transporter Mfsd2a maintains pulmonary surfactant homeostasis. J Biol Chem 2022; 298:101709. [PMID: 35150739 PMCID: PMC8914330 DOI: 10.1016/j.jbc.2022.101709] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 11/18/2022] Open
Abstract
Pulmonary surfactant is a lipoprotein complex essential for lung function, and insufficiency or altered surfactant composition is associated with major lung diseases, such as acute respiratory distress syndromes, idiopathic pulmonary fibrosis, and chronic obstructive pulmonary disease. Pulmonary surfactant is primarily composed of phosphatidylcholine (PC) in complex with specialized surfactant proteins and secreted by alveolar type 2 (AT2) cells. Surfactant homeostasis on the alveolar surface is balanced by the rates of synthesis and secretion with reuptake and recycling by AT2 cells, with some degradation by pulmonary macrophages and loss up the bronchial tree. However, whether phospholipid (PL) transporters exist in AT2 cells to mediate reuptake of surfactant PL remains to be identified. Here, we demonstrate that major facilitator superfamily domain containing 2a (Mfsd2a), a sodium-dependent lysophosphatidylcholine (LPC) transporter, is expressed at the apical surface of AT2 cells. A mouse model with inducible AT2 cell–specific deficiency of Mfsd2a exhibited AT2 cell hypertrophy with reduced total surfactant PL levels because of reductions in the most abundant surfactants, PC containing dipalmitic acid, and PC species containing the omega-3 fatty acid docosahexaenoic acid. These changes in surfactant levels and composition were mirrored by similar changes in the AT2 cell lipidome. Mechanistically, direct tracheal instillation of fluorescent LPC and PC probes indicated that Mfsd2a mediates the uptake of LPC generated by pulmonary phospholipase activity in the alveolar space. These studies reveal that Mfsd2a-mediated LPC uptake is quantitatively important in maintaining surfactant homeostasis and identify this lipid transporter as a physiological component of surfactant recycling.
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Affiliation(s)
- Bernice H Wong
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Ding Mei
- Singapore Lipidomics Incubator, Life Sciences Institute, National University of Singapore, Singapore, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Geok Lin Chua
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Dwight L Galam
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Markus R Wenk
- Singapore Lipidomics Incubator, Life Sciences Institute, National University of Singapore, Singapore, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Federico Torta
- Singapore Lipidomics Incubator, Life Sciences Institute, National University of Singapore, Singapore, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - David L Silver
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore.
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5
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Postle AD, Clark HW, Fink J, Madsen J, Koster G, Panchal M, Djukanovic R, Brealey D, Grocott MPW, Dushianthan A. Rapid Phospholipid Turnover After Surfactant Nebulization in Severe COVID-19 Infection: A Randomized Clinical Trial. Am J Respir Crit Care Med 2021; 205:471-473. [PMID: 34874818 PMCID: PMC8886955 DOI: 10.1164/rccm.202110-2279le] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Anthony D Postle
- University of Southampton, Child Health, Southampton, United Kingdom of Great Britain and Northern Ireland;
| | - Howard W Clark
- University College London Faculty of Medical Sciences, 61142, EGA Institute for Women's Health, London, United Kingdom of Great Britain and Northern Ireland
| | - Jim Fink
- Aerogen Pharma Corporation, San Mateo, California, United States
| | - Jens Madsen
- University College London Faculty of Medical Sciences, 61142, EGA Institute for Women's Health,, London, United Kingdom of Great Britain and Northern Ireland
| | - Grielof Koster
- University of Southampton Faculty of Medicine, 12211, National Institute for Health Research (NIHR) Southampton Biomedical Research Centre , Southampton, United Kingdom of Great Britain and Northern Ireland
| | - Madhuriben Panchal
- University of Southampton Faculty of Medicine, 12211, National Institute for Health Research (NIHR) Southampton Biomedical Research Centre , Southampton, United Kingdom of Great Britain and Northern Ireland
| | - Ratko Djukanovic
- Southampton University, Clinical and Experimental Sciences and Southampton NIHR Respiratory Biomedical Research Unit, Southampton, United Kingdom of Great Britain and Northern Ireland
| | - David Brealey
- University College London, 4919, Bloomsbury Institute of Intensive Care Medicine, London, United Kingdom of Great Britain and Northern Ireland.,University College London Hospitals NHS Foundation Trust, 8964, Department of Critical Care, London, United Kingdom of Great Britain and Northern Ireland
| | - Michael P W Grocott
- University of Southampton Faculty of Medicine, 12211, Southampton, United Kingdom of Great Britain and Northern Ireland
| | - Ahilanandan Dushianthan
- University Hospital Southampton NHS Foundation Trust, 7425, General Intensive Care Unit, Southampton, United Kingdom of Great Britain and Northern Ireland
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6
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General characteristics of the influence of surfactants on the bacteriolytic activity of lysozyme based on the example of enzymatic lysis of Lactobacillus plantarum cells in the presence of Tween 21 and SDS. Biochem Biophys Res Commun 2021; 575:73-77. [PMID: 34461438 DOI: 10.1016/j.bbrc.2021.08.060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 08/20/2021] [Indexed: 11/23/2022]
Abstract
The general characteristics of the effect of surfactants on the activity of lysozyme were demonstrated. The kinetics of bacterial cell lysis is consistent with the Michaelis-Menten equation and the presence of surfactants does not shift the pH-optimum of activity. Surfactants do not change the Km value but instead, affect the Vmax value. The experimental dependencies are well described by theoretical equations, which assume three surfactant binding sites on the lysozyme molecule. The dependencies of the activity of lysozyme on the surfactant concentration are either a step type (i.e., a higher plateau becomes a lower plateau), or a dependency with a maximum and continuation of the curve in the form of a plateau but with an increase in the surfactant concentration. It can be assumed that there is a mechanism for the regulation of lysozyme activity by an unknown natural factor that has a suitable hydrophobic radical capable of binding to the surface of lysozyme.
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7
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Pioselli B, Salomone F, Mazzola G, Amidani D, Sgarbi E, Amadei F, Murgia X, Catinella S, Villetti G, De Luca D, Carnielli V, Civelli M. Pulmonary surfactant: a unique biomaterial with life-saving therapeutic applications. Curr Med Chem 2021; 29:526-590. [PMID: 34525915 DOI: 10.2174/0929867328666210825110421] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 06/26/2021] [Accepted: 06/29/2021] [Indexed: 11/22/2022]
Abstract
Pulmonary surfactant is a complex lipoprotein mixture secreted into the alveolar lumen by type 2 pneumocytes, which is composed by tens of different lipids (approximately 90% of its entire mass) and surfactant proteins (approximately 10% of the mass). It is crucially involved in maintaining lung homeostasis by reducing the values of alveolar liquid surface tension close to zero at end-expiration, thereby avoiding the alveolar collapse, and assembling a chemical and physical barrier against inhaled pathogens. A deficient amount of surfactant or its functional inactivation is directly linked to a wide range of lung pathologies, including the neonatal respiratory distress syndrome. This paper reviews the main biophysical concepts of surfactant activity and its inactivation mechanisms, and describes the past, present and future roles of surfactant replacement therapy, focusing on the exogenous surfactant preparations marketed worldwide and new formulations under development. The closing section describes the pulmonary surfactant in the context of drug delivery. Thanks to its peculiar composition, biocompatibility, and alveolar spreading capability, the surfactant may work not only as a shuttle to the branched anatomy of the lung for other drugs but also as a modulator for their release, opening to innovative therapeutic avenues for the treatment of several respiratory diseases.
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Affiliation(s)
| | | | | | | | - Elisa Sgarbi
- Preclinical R&D, Chiesi Farmaceutici, Parma. Italy
| | | | - Xabi Murgia
- Department of Biotechnology, GAIKER Technology Centre, Zamudio. Spain
| | | | | | - Daniele De Luca
- Division of Pediatrics and Neonatal Critical Care, Antoine Béclère Medical Center, APHP, South Paris University Hospitals, Paris, France; Physiopathology and Therapeutic Innovation Unit-U999, South Paris-Saclay University, Paris. France
| | - Virgilio Carnielli
- Division of Neonatology, G Salesi Women and Children's Hospital, Polytechnical University of Marche, Ancona. Italy
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8
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Ellis SR, Hall E, Panchal M, Flinders B, Madsen J, Koster G, Heeren RMA, Clark HW, Postle AD. Mass spectrometry imaging of phosphatidylcholine metabolism in lungs administered with therapeutic surfactants and isotopic tracers. J Lipid Res 2021; 62:100023. [PMID: 33453219 PMCID: PMC7961103 DOI: 10.1016/j.jlr.2021.100023] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/18/2020] [Accepted: 01/06/2021] [Indexed: 12/11/2022] Open
Abstract
Mass spectrometry imaging (MSI) visualizes molecular distributions throughout tissues but is blind to dynamic metabolic processes. Here, MSI with high mass resolution together with multiple stable isotope labeling provided spatial analyses of phosphatidylcholine (PC) metabolism in mouse lungs. Dysregulated surfactant metabolism is central to many respiratory diseases. Metabolism and turnover of therapeutic pulmonary surfactants were imaged from distributions of intact and metabolic products of an added tracer, universally 13C-labeled dipalmitoyl PC (U13C-DPPC). The parenchymal distributions of newly synthesized PC species were also imaged from incorporations of methyl-D9-choline. This dual labeling strategy demonstrated both lack of inhibition of endogenous PC synthesis by exogenous surfactant and location of acyl chain remodeling processes acting on the U13C-DPPC-labeled surfactant, leading to formation of polyunsaturated PC lipids. This ability to visualize discrete metabolic events will greatly enhance our understanding of lipid metabolism in diverse tissues and has potential application to both clinical and experimental studies.
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Affiliation(s)
- Shane R Ellis
- Division of Imaging Mass Spectrometry, Maastricht MultiModal Molecular Imaging (M4I) Institute, Maastricht University, Maastricht, The Netherlands; Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales, Australia; Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.
| | - Emily Hall
- Academic Unit of Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Madhuriben Panchal
- Academic Unit of Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom; National Institute for Health Research Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, United Kingdom
| | - Bryn Flinders
- Division of Imaging Mass Spectrometry, Maastricht MultiModal Molecular Imaging (M4I) Institute, Maastricht University, Maastricht, The Netherlands
| | - Jens Madsen
- Elizabeth Garrett Anderson Institute for Women's Health, Faculty of Population Health Sciences, University College London, London, United Kingdom
| | - Grielof Koster
- Academic Unit of Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom; National Institute for Health Research Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, United Kingdom
| | - Ron M A Heeren
- Division of Imaging Mass Spectrometry, Maastricht MultiModal Molecular Imaging (M4I) Institute, Maastricht University, Maastricht, The Netherlands
| | - Howard W Clark
- Elizabeth Garrett Anderson Institute for Women's Health, Faculty of Population Health Sciences, University College London, London, United Kingdom; National Institute for Health Biomedical Research Centre, University College London Hospital Biomedical Research Centre, London, United Kingdom
| | - Anthony D Postle
- Academic Unit of Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom; National Institute for Health Research Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, United Kingdom.
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9
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Abstract
Purpose of Review Lung tissues are highly susceptible to airway inflammation as they are inevitably exposed to inhaled pathogens and allergens. In the lungs, clearance of infectious agents and regulation of inflammatory responses are important for the first-line defense, where surfactants play a role in host defense mechanisms. In this review, clinical significance of pulmonary surfactants in asthma has been highlighted. Recent Findings Surfactants, such as surfactant protein A (SP-A) and SP-D released from alveolar epithelium, reduce pathogen infection and control immune-cell activation. Especially, SP-D directly binds to eosinophil surface, leading to inhibition of extracellular trap formation and reduction in airway inflammation. Production of surfactants is commonly determined by both genetic (single nucleotide polymorphisms) and environmental factors influencing processes involved in the development of asthma. In addition, nintedanib (an intracellular inhibitor of tyrosine kinases) could increase SP-D levels and is used in patients with idiopathic pulmonary fibrosis. These findings may provide a possible application of SP-D in asthma. Summary Surfactants are key players contributing to host defense through maintaining the immune system. As clinical implications of surfactants involved in asthma have been suggested, further translational studies are needed to apply surfactants as an effective therapeutic target in patients with asthma.
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Affiliation(s)
- Youngwoo Choi
- Department of Allergy and Clinical Immunology, Ajou University School of Medicine, 164 Worldcup-ro, Yeongtong-gu, Suwon, 16499, South Korea
| | - Jaehyuk Jang
- Department of Allergy and Clinical Immunology, Ajou University School of Medicine, 164 Worldcup-ro, Yeongtong-gu, Suwon, 16499, South Korea
| | - Hae-Sim Park
- Department of Allergy and Clinical Immunology, Ajou University School of Medicine, 164 Worldcup-ro, Yeongtong-gu, Suwon, 16499, South Korea.
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10
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Surfactant replacement therapy: from biological basis to current clinical practice. Pediatr Res 2020; 88:176-183. [PMID: 31926483 PMCID: PMC7223236 DOI: 10.1038/s41390-020-0750-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 12/15/2019] [Accepted: 12/20/2019] [Indexed: 02/05/2023]
Abstract
This review summarizes the current knowledge on the physiological action of endogenous and exogenous pulmonary surfactant, the role of different types of animal-derived and synthetic surfactants for RDS therapy, different modes of administration, potential risks and strategies of ventilation, and highlights the most promising aims for future development. Scientists have clarified the physicochemical properties and functions of the different components of surfactant, and part of this successful research is derived from the characterization of genetic diseases affecting surfactant composition or function. Knowledge from functional tests of surfactant action, its immunochemistry, kinetics and homeostasis are important also for improving therapy with animal-derived surfactant preparations and for the development of modified surfactants. In the past decade newly designed artificial surfactants and additives have gained much attention and have proven different advantages, but their particular role still has to be defined. For clinical practice, alternative administration techniques as well as postsurfactant ventilation modes, taking into account alterations in lung mechanics after surfactant placement, may be important in optimizing the potential of this most important drug in neonatology.
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11
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Giambelluca S, Ricci F, Simonato M, Vedovelli L, Traldi U, Correani A, Casiraghi C, Storti M, Mersanne A, Cogo P, Salomone F, Carnielli VP. Tracing exogenous surfactant in vivo in rabbits by the natural variation of 13C. Respir Res 2019; 20:158. [PMID: 31319861 PMCID: PMC6637643 DOI: 10.1186/s12931-019-1124-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 07/03/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Respiratory Distress Syndrome (RDS) is a prematurity-related breathing disorder caused by a quantitative deficiency of pulmonary surfactant. Surfactant replacement therapy is effective for RDS newborns, although treatment failure has been reported. The aim of this study is to trace exogenous surfactant by 13C variation and estimate the amount reaching the lungs at different doses of the drug. METHODS Forty-four surfactant-depleted rabbits were obtained by serial bronchoalveolar lavages (BALs), that were merged into a pool (BAL pool) for each animal. Rabbits were in nasal continuous positive airway pressure and treated with 0, 25, 50, 100 or 200 mg/kg of poractant alfa by InSurE. After 90 min, rabbits were depleted again and a new pool (BAL end experiment) was collected. Disaturated-phosphatidylcholine (DSPC) was measured by gas chromatography. DSPC-Palmitic acid (PA) 13C/12C was analyzed by isotope ratio mass spectrometry. One-way non-parametric ANOVA and post-hoc Dunn's multiple comparison were used to assess differences among experimental groups. RESULTS Based on DSPC-PA 13C/12C in BAL pool and BAL end experiment, the estimated amount of exogenous surfactant ranged from 61 to 87% in dose-dependent way (p < 0.0001) in animals treated with 25 up to 200 mg/kg. Surfactant administration stimulated endogenous surfactant secretion. The percentage of drug recovered from lungs did not depend on the administered dose and accounted for 31% [24-40] of dose. CONCLUSIONS We reported a risk-free method to trace exogenous surfactant in vivo. It could be a valuable tool for assessing, alongside the physiological response, the delivery efficiency of surfactant administration techniques.
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Affiliation(s)
- Sonia Giambelluca
- Department of Women's and Children's Health, University of Padova, Padova, Italy.,PCare Laboratory, Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Corso Stati Uniti, 4F, Padova, 35121, Italy
| | | | - Manuela Simonato
- PCare Laboratory, Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Corso Stati Uniti, 4F, Padova, 35121, Italy. .,Institute of Anesthesiology and Intensive Care, Department of Medicine - DIMED, University of Padova, Padova, Italy.
| | - Luca Vedovelli
- PCare Laboratory, Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Corso Stati Uniti, 4F, Padova, 35121, Italy
| | | | - Alessio Correani
- Division of Neonatology, Department of Clinical Sciences, Polytechnic University of Marche and Azienda Ospedaliero-Universitaria Ospedali Riuniti, Ancona, Italy
| | | | | | | | - Paola Cogo
- Department of Medicine, University of Udine, Udine, Italy
| | | | - Virgilio P Carnielli
- Division of Neonatology, Department of Clinical Sciences, Polytechnic University of Marche and Azienda Ospedaliero-Universitaria Ospedali Riuniti, Ancona, Italy
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12
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Brown NJ, Lin JS, Barron AE. Helical side chain chemistry of a peptoid-based SP-C analogue: Balancing structural rigidity and biomimicry. Biopolymers 2019; 110:e23277. [PMID: 30972750 DOI: 10.1002/bip.23277] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 03/15/2019] [Accepted: 03/18/2019] [Indexed: 01/21/2023]
Abstract
Surfactant protein C (SP-C) is an important constituent of lung surfactant (LS) and, along with SP-B, is included in exogenous surfactant replacement therapies for treating respiratory distress syndrome (RDS). SP-C's biophysical activity depends upon the presence of a rigid C-terminal helix, of which the secondary structure is more crucial to functionality than precise side-chain chemistry. SP-C is highly sequence-conserved, suggesting that the β-branched, aliphatic side chains of the helix are also important. Nonnatural mimics of SP-C were created using a poly-N-substituted glycine, or "peptoid," backbone. The mimics included varying amounts of α-chiral, aliphatic side chains and α-chiral, aromatic side chains in the helical region, imparting either biomimicry or structural rigidity. Biophysical studies confirmed that the peptoids mimicked SP-C's secondary structure and replicated many of its surface-active characteristics. Surface activity was optimized by incorporating both structurally rigid and biomimetic side chain chemistries in the helical region indicating that both characteristics are important for activity. By balancing these features in one mimic, a novel analogue was created that emulates SP-C's in vitro surface activity while overcoming many of the challenges related to natural SP-C. Peptoid-based analogues hold great potential for use in a synthetic, biomimetic LS formulation for treating RDS.
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Affiliation(s)
- Nathan J Brown
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois
| | - Jennifer S Lin
- Department of Bioengineering, Stanford University, Stanford, California
| | - Annelise E Barron
- Department of Bioengineering, Stanford University, Stanford, California
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