Pulmonary surfactant is a surfaceactive lipoprotein complex phospholipoprotein formed by type ii alveolar cells. The function of phosphatidylglycerol can be replaced functionally by phosphatidylinositol without physiologic consequences. Pulmonary surfactant in health and disease diseases of. Lack or dysfunction of this pulmonary surfactant is associated with severe, often lethal, respiratory pathologies. By adsorbing to the airwater interface of alveoli, with hydrophilic head groups in the water and the hydrophobic tails facing towards the air, the main lipid component of surfactant. It also uses cookies for the purposes of performance measurement. The administration of exogenous surfactants, including curosurf, can rapidly affect oxygenation and lung compliance. It is well over 40 years since pattle revived interest in pulmonary surfactant and perhaps a good time to see where we find current investigators working. Pulmonary surfactant is a complex mixture of phospholipids and proteins that functions to reduce surface tension at the alveolar air interface preventing atelectasis. Phosphatidylcholine composition of pulmonary surfactant from. It is a membranebound protein that constitutes 12% of the pulmonary surfactant mass. Phosphatidylcholine composition of pulmonary surfactant. The proteins and lipids that make up the surfactant have both hydrophilic and hydrophobic regions.
Representative composition of bovine surfactant from lung lavage fluid is shown. While the role of surfactant in the alveolar compartment has been intensively elucidated both in health and. Composition of human pulmonary surfactant varies with exercise and level of fitness article pdf available in american journal of respiratory and critical care medicine 1496. Its specific function is to reduce surface tension at the pulmonary airliquid interface. Pulmonary surfactant is a complex mixture of phospholipids and proteins that functions to reduce surface tension at the alveolar air interface preventing.
A lipoprotein secreted by type ii alveolar cells that decreases the surface tension of the fluid lining the alveoli, permitting expansion. Without normal surfactant, the tissue surrounding the air sacs in the. Surfactant is secreted by the type ii alveolar epithelial cells in response to beta adrenergic stimulation and the synthesis is increased by corticosteroids. Pulmonary surface tension and the mucus lining of the lungs. However, in a variety of subacute diseases of the mature lung, abnormalities of lung surfactant may also be of importance.
Introduction the lungs of preterm infants lack adequate pulmonary surfactant, a constituent of the air liquid interface, that normally lines the alveolar surfaces and terminal airways. Pdf composition of human pulmonary surfactant varies. It is well over 40 years since pattle revived interest in pulmonary surfactant 1. The importance of surfactant on the development of neonatal. All structured data from the file and property namespaces is available under the creative commons cc0 license. Pulmonary surfactant in newborn infants and children european. Buffalos historic role in surfactant therapy, and the man. Phosphatidylglycine 5% a reduction in the percentage of phosphatidylglycerol is the earliest and most sensitive alteration in the composition of surfactant in lung injury. This article starts with a brief account of the history of research on pulmonary surfactant. This protein is one of four proteins each produced from a different gene in surfactant, a mixture of certain fats called phospholipids and proteins that lines the lung tissue and makes breathing easy. In respiratory function, especially in the age of 2 to 4 months, plays a special role of pulmonary surfactant.
Synthetic lung surfactant drug information, professional. Cigarette smoke is an important risk factor for copd and it is known to adversely affect surfactant. Natural surfactant is produced by the alveolar cells in the lungs and line mainly the alveoli and small bronchioles, and prevents the alveoli from collapsing. Pulmonary surfactant is a lipidrich material that prevents lung collapse by lowering surface tension at. The amount of surfactant, estimated by quantitative spreading as a surface film, correlates well with alveolar surface area and with the amount of saturated, mainly dipalmitoyl, phosphatidylcholine in the lung parenchyma. Pulmonary surfactant protein d in sera and bronchoalveolar. Pulmonary surfactant lowers surface tension in the lungs. The underlying younglaplace equation, applying to the surface of any geometrical structure, is the more important the smaller its radii are. Following the initial inspiration after birth, when babies first generate the airwater interface, pulmonary mechanics are normal within the initial or first few exhalations lachmann et al. Pulmonary surfactant definition of pulmonary surfactant. Pulmonary surfactant has been looked for and found in 11 representatives of four vertebrate classes.
Curosurf poractant alfa is intended for intratracheal use only. The airspaces of the lung may be compared to several hundred million bubbles blown on airways, and the surface tension necessary to prevent alveolar emptying can be estimated. Surfactant was isolated from minced adult human lung tissues by repetitive centrifugation on nabr density gradients. Eighty percent of the phospholipid was phosphatidylcholine and 9% was phosphatidylglycerol. Surfactant dysfunction genetics home reference nih. Miller nj, postle ad, schurch s, michael schoel w, daniels cb, orgeig s.
As an alveolus becomes smaller during expiration, the surfactant becomes more concentrated, further reducing the surface tension and preventing alveolar collapse. Respiratory physiology surfactant 17 mcqs flashcards. The phospholipid composition of bovine pulmo nary surfactant, which is representative of. The alveolar region of the lung creates an extensive epithelial surface that mediates the transfer of oxygen and carbon dioxide required for respiration after birth. Pulmonary surfactant article about pulmonary surfactant. Pulmonary surfactant is produced by cells within the lungs and decreases surface tension by breaking bonds between water molecules. Recent studies indicate adsorbed surfactant films consist of a surface monolayer and a monolayerassociated reservoir. In vitro functional and structural characterization of a synthetic. Lung surfactant makes it easier for oxygen to penetrate the lung surface lining and move into the blood. Quiz will load in 5 seconds, if not click on start quiz button below.
It is characterized by alveolar filling with floccular material that stains positive using the periodic acidschiff method and is derived from surfactant phospholipids and protein components. Pulmonary surfactant is a complex mixture of phospholipids pl and proteins sp that reduce surface tension at the airliquid interface of the alveolus. The sftpc gene provides instructions for making a protein called surfactant proteinc spc. The role of surfactant in asthma respiratory research. However, pulmonary surfactant composition has not yet been. Factors such as composition and concentration may affect the kinetics of. Surfactant dysfunction is a lung disorder that causes breathing problems. It also participates in innate host defense against inhaled pathogens.
Pulmonary surfactant isolated by lung lavage consists of highly heterogeneous forms of phospholipidprotein aggregates of distinct sizes, structural characteristics, and composition. This chapter on surfactant composition and function has been limited to. Pulmonary surfactant is composed primarily of phospholipids and key proteins. Pdf composition of human pulmonary surfactant varies with. Therefore, infants receiving curosurf should receive frequent clinical and laboratory assessments so that oxygen and ventilatory support can be modified to respond to respiratory changes. It wasnt until the mid1980s that scientists made the critical discovery that these apoproteins of pulmonary surfactant, which have since been named spb and spc, are essential for an immediate expression of surface activity. Annals of the american thoracic society ats journals.
The proteins and lipids that comprise surfactant have both a hydrophilic region and a hydrophobic region. Pulmonary surfactant is a surface active material composed of both lipids and proteins that is produced by alveolar type ii pneumocytes. Lipid compositional analysis of pulmonary surfactant monolayers and monolayerassociated reservoirs, 2003. Prevention is generally done in babies born at a gestational age of less than 32 weeks. Pulmonary surfactant is a surfaceactive lipoprotein complex formed by type ii alveolar cells. Lung surfactant in subacute pulmonary disease respiratory. This condition results from abnormalities in the composition or function of surfactant, a mixture of certain fats called phospholipids and proteins that lines the lung tissue and makes breathing easy. Therefore, we investigated surfactant phospholipid composition and function in bal fluid from infants who. Pulmonary surfactant is a lipidrich material that prevents lung collapse by lowering surface tension at the airliquid interface in the alveoli of lung.
This chapter on surfactant composition and function has been limited to introducing some issues related to its surface activity, leaving subsequent authors to fill in many of the detai. Pulmonary surfactant function and ventilation video. Files are available under licenses specified on their description page. We will then discuss the morphological aspects and composition of the pulmonary surfactant system. Pulmonary surfactant synonyms, pulmonary surfactant pronunciation, pulmonary surfactant translation, english dictionary definition of pulmonary surfactant. Handbook of physiology, american physiological society, washington, dc, 1986, pp. Mar 21, 20 it wasnt until the mid1980s that scientists made the critical discovery that these apoproteins of pulmonary surfactant, which have since been named spb and spc, are essential for an immediate expression of surface activity.
By adsorbing to the airwater interface of alveoli, with hydrophilic head groups in the water and the hydrophobic tails facing. Pulmonary surfactant is used as a medication to treat and prevent respiratory distress syndrome in newborn babies. This chapter on surfactant composition and function has been limited to introducing some issues related to its surface activity, leaving subsequent authors to fill in many of the details. The phosphatidylcholines, 55% of which were disaturated, contained more than 70% palmitic acid. Pulmonary surfactants and their role in pathophysiology of. Oct 15, 2001 pulmonary surfactant is a unique mixture of lipids and surfactant specific proteins that covers the entire alveolar surface of the lungs. Decreased mortality rate among small premature infants treated at birth with a single dose of synthetic surfactant. Jan 11, 2017 the composition of surfactant lipids is similar in all of the structural forms of surfactant isolated from mammalian lungs, with phospholipids generally representing 80% to 90% of the mass of pulmonary surfactant. Jun 12, 2012 commercial natural surfactant types and composition surfactant conc ofsurfactant origin protein b initial dose repeat dosing schedule phospholipid content porcine lung minces, lipid extraction withporactant 0. The surface active fraction contained 12 mg phospholipid per mg of protein.
Alveolar surfactant homeostasis and the pathogenesis of. A pulmonary surfactant associated protein that plays a role in alveolar stability by lowering the surface tension at the airliquid interface. The biophysical function of pulmonary surfactant ncbi. This is a pdf file of an unedited manuscript that has. Future studies of the effect of exogenous surfactant in children and adults with ards should use the same surfactant and include a study design that can. Surfactant is not restricted to the alveolar compartment. Possmayer and i extracted the phospholipids from the material. Indeed, the regulation of alveolar surfactant composition and its secretory rate into the alveoli is itself a superb example of metabolic regulation in practice. Pulmonary surfactant definition of pulmonary surfactant by.
Lung surfactant definition of lung surfactant by medical. The importance of surfactant on the development of. If the alveolar surface were made of a transudate of plasma, we would expect the alveoli to be empty at the end of expiration. Spb is a hydrophobic protein and constitutes 2% of the surfactant composition. Function and composition in the context of development and respiratory physiology lung surfactant is a complex with a unique phospholipid and protein composition. Lung surfactants are made from animal lung extract and contain phospholipids. An overview of pulmonary surfactant in the neonate.
The quantities of other phospholipids do not correlate. Pulmonary surfactant is a mixture of phospholipids and proteins synthesized in alveolar typeii. Surfactant composition and function in patients with abca3. Pulmonary surfactant and evolution of the lungs science. Pulmonary surfactant in health and disease diseases of the. Maintenance of pulmonary function depends on the function of type ii epithelial cells that synthesize and secrete pulmonary surfactant lipids and proteins, reducing the collapsing forces created at the airliquid interface in the. Role of surfactant in chronic obstructive pulmonary. A pulmonary surfactant associated protein that plays a role in alveolar stability by lowering the surface tension at the airliquid interfaceit is a membranebound protein that constitutes 12% of the pulmonary surfactant mass.
Pdf surfactant is an agent that decreases the surface tension between two media. Pulmonary surfactant an overview sciencedirect topics. Regulation of pulmonary surfactant secretion and clearance. Lipids compose 80 to 90% of its molecular weight, of which the most abundant species are phosphatidylcholine, phosphatidylglycerol, and phosphatidylinositol.
Therefore, pulmonary surfactant allows the lungs to expand so we. This study aims to describe the healthrelated quality of life, pulmonary lung function, incidence of bronchial hyperresponsiveness, body composition, and trends in physical activity of young adults born prematurely, with or without respiratory complications such as rds and bpd, and to compare these with young adults born at term. It is made up of about 70% to 80% pl, mainly dipalmitoylphosphatidylcholine dppc, 10% spa, b. Pulmonary surfactant is a unique mixture of lipids and surfactantspecific proteins that covers the entire alveolar surface of the lungs. Abnormalities of surfactant in the immature lung or in the acutely inflamed mature lung are well described. Therapeutic implications, abstract a potential role of surfactant in copd pathogenesis is not yet clearly demonstrated.
By adsorbing to the airwater interface of alveoli with the hydrophilic headgroups in the water and the hydrophobic tails facing towards. Surfactant lowering pulmonary surface tension owlcation. Rds is due to surfactant deficiency, which increases the surface tension at the airliquid interface of the terminal respiratory units. Pulmonary surfactant is a complex mixture of phospholipids pl and proteins sp that reduce surface tension at the airliquid interface of the alveolus, thus preventing its collapse during endexhalation 1,2. We have recently prepared monoclonal antibodies against human spd and developed an enzymelinked immunosorbent assay elisa. Tubular myelin is the most abundant form of alveolar phospholipid and consists of large, relatively dense aggregates termed large aggregate surfactant composed.
Pulmonary surfactant and disorders of surfactant homeostasis. Pdf pulmonary surfactants and their role in pathophysiology of. Excessive lipoproteins accumulation in the alveoli results in severe respiratory distress. A rare lung disorder due to impaired surfactant homeostasis. Deficiency of pulmonary surfactant is the principal cause of respiratory distress syndrome in premature infants whitsett and weaver, 2002. Pulmonary surfactantassociated protein c is one of the most hydrophobic peptides yet isolated and contains an alpha. Funding and disclosures supported in part by grants hd11932, hd12719, and hd20618. We describe the hydrophilic surfactant proteins a and d and the hydrophobic surfactant proteins b and c, with focus on the crucial roles of these proteins in the dynamics, metabolism, and functions of. The composition of pulmonary surfactant from diving mammals. In obstetrics, fetal production of surfactant can be stimulated by administration of a. The development of the pulmonary surfactant system in california sea lions. The sftpb gene encodes the pulmonary associated surfactant b protein spb, an amphipathic surfactant protein essential for lung function and homeostasis after birth. Pulmonary surfactant protein d spd is a hydrophilic glycoprotein with a reduced molecular mass of 43 kda and a member of the ctype lectin superfamily, along with mannosebinding proteins and surfactant protein a spa. Synthetic lung surfactant is available for treating patients with respiratory distress syndrome.
Pulmonary surfactant is a complex mixture of phospholipids, neutral lipids, and specific proteins. Future studies of the effect of exogenous surfactant in children and adults with ards should use the. Lung surfactant is a complex with a unique phospholipid and protein composition. The sftpb gene encodes the pulmonaryassociated surfactant b protein spb, an amphipathic surfactant protein essential for lung function and homeostasis after birth. The spontaneous curvature of a lipid leaflet, obtained in the absence of applied force. Instead, current evidence indicates that the surface tension of the lung varies widely and. It is made up of about 70% to 80% pl, mainly dipalmitoylphosphatidylcholine dppc, 10% spa, b, c and d, and 10% neutral lipids, mainly cholesterol. Structural and functional impairments of the pulmonary surfactant lead to aggravation of hypoxia, which is the basis of many respiratory diseases in children and adults enhorning, 2008. In anesthetized adult animals ventilated at a low constant tidal. The clinical potential of surfactant treatment for respiratory distress syndrome was demonstrated by.
Biochemical composition of adult human lung surfactant. Lipid compositional analysis of pulmonary surfactant monolayers. Surfactant is a mixture of dipalmatoilphosphatidylcholine 40%, other phospholipids 40%, surfactant associated proteins 5% and other minor compounds like cholesterol 5%. Surfactant is synthesized and secreted by type ii alveolar epithelial cells, also. Pulmonary surfactant consists of 90% lipids and 10% protein. Pulmonary surfactant article about pulmonary surfactant by.