scholarly journals Interfacial curvature effects on the monolayer morphology and dynamics of a clinical lung surfactant

2017 ◽  
Vol 115 (2) ◽  
pp. E134-E143 ◽  
Author(s):  
Amit Kumar Sachan ◽  
Joseph A. Zasadzinski
Keyword(s):  
Lung Surfactant ◽  
Morphological Transition ◽  
Surfactant Adsorption ◽  
Langmuir Trough ◽  
Planar Surface ◽  
Lung Surfactants ◽  
Surfactant Monolayers ◽  
Curvature Effects ◽  
And Function ◽  
Micrometer Scale

The morphology of surfactant monolayers is typically studied on the planar surface of a Langmuir trough, even though most physiological interfaces are curved at the micrometer scale. Here, we show that, as the radius of a clinical lung surfactant monolayer-covered bubble decreases to ∼100 µm, the monolayer morphology changes from dispersed circular liquid-condensed (LC) domains in a continuous liquid-expanded (LE) matrix to a continuous LC linear mesh separating discontinuous LE domains. The curvature-associated morphological transition cannot be readily explained by current liquid crystal theories based on isotropic domains. It is likely due to the anisotropic bending energy of the LC phase of the saturated phospholipids that are common to all natural and clinical lung surfactants. This continuous LC linear mesh morphology is also present on bilayer vesicles in solution. Surfactant adsorption and the dilatational modulus are also strongly influenced by the changes in morphology induced by interfacial curvature. The changes in morphology and dynamics may have physiological consequences for lung stability and function as the morphological transition occurs at alveolar dimensions.

scholarly journals Design of Surfactant Protein B Peptide Mimics Based on the Saposin Fold for Synthetic Lung Surfactants

2016 ◽  
Vol 1 (3) ◽  
pp. 1-21 ◽  
Author(s):  
Frans J. Walther ◽  
Larry M. Gordon ◽  
Alan J. Waring
Keyword(s):  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Molecular Design ◽  
Lung Surfactant ◽  
Three Dimensional ◽  
Surfactant Protein ◽  
Structural Motif ◽  
Lung Surfactants ◽  
Design Synthesis

Surfactant protein (SP)-B is a 79-residue polypeptide crucial for the biophysical and physiological function of endogenous lung surfactant. SP-B is a member of the saposin or saposin-like proteins (SAPLIP) family of proteins that share an overall three-dimensional folding pattern based on secondary structures and disulfide connectivity and exhibit a wide diversity of biological functions. Here, we review the synthesis, molecular biophysics and activity of synthetic analogs of saposin proteins designed to mimic those interactions of the parent proteins with lipids that enhance interfacial activity. Saposin proteins generally interact with target lipids as either monomers or multimers via well-defined amphipathic helices, flexible hinge domains, and insertion sequences. Based on the known 3D-structural motif for the saposin family, we show how bioengineering techniques may be used to develop minimal peptide constructs that maintain desirable structural properties and activities in biomedical applications. One important application is the molecular design, synthesis and activity of Saposin mimics based on the SP-B structure. Synthetic lung surfactants containing active SP-B analogs may be potentially useful in treating diseases of surfactant deficiency or dysfunction including the neonatal respiratory distress syndrome and acute lung injury/acute respiratory distress syndrome.

scholarly journals Effect of triiodothyronine augmentation on rat lung surfactant phospholipids during sepsis

1997 ◽  
Vol 82 (6) ◽  
pp. 2020-2027 ◽  
Author(s):  
Sergey M. Ksenzenko ◽  
Scott B. Davidson ◽  
Amer A. Saba ◽  
Alexander P. Franko ◽  
Aml M. Raafat ◽  
...  
Keyword(s):  
Lung Surfactant ◽  
Cecal Ligation ◽  
Active Role ◽  
Lung Compliance ◽  
Rat Lung ◽  
Sprague Dawley ◽  
Surfactant Phospholipids ◽  
Surfactant Composition ◽  
And Function

Ksenzenko, Sergey M., Scott B. Davidson, Amer A. Saba, Alexander P. Franko, Aml M. Raafat, Lawrence N. Diebel, and Scott A. Dulchavsky. Effect of triiodothyronine augmentation on rat lung surfactant phospholipids during sepsis. J. Appl. Physiol. 82(6): 2020–2027, 1997.—Surfactant functional effectiveness is dependent on phospholipid compositional integrity; sepsis decreases this through an undefined mechanism. Sepsis-induced hypothyroidism is commensurate and may be related. This study examines the effect of 3,3′,5-triiodo-l-thyronine (T3) supplementation on surfactant composition and function during sepsis. Male Sprague-Dawley rats underwent sham laparotomy (Sham) or cecal ligation and puncture (CLP) with or without T3supplementation [CLP/T3 (3 ng/h)]. After 6, 12, or 24 h, surfactant was obtained by lavage. Function was assessed by a pulsating bubble surfactometer and in vivo compliance studies. Sepsis produced a decrease in surfactant phosphatidylglycerol and phosphatidic acid, with an increase in lesser surface-active lipids phosphatidylserine and phosphatidylinositol. Phosphatidylcholine content was not significantly changed. Sepsis caused an alteration in the fatty acid composition and an increase in saturation in most phospholipids. Hormonal replacement attenuated these changes. Lung compliance and surfactant adsorption were reduced by sepsis and maintained by T3treatment. Thyroid hormone may have an active role in lung functional preservation through maintenance of surfactant homeostasis during sepsis.

scholarly journals The role of SP-B1–25 peptides in lung surfactant monolayers exposed to gold nanoparticles

2020 ◽  
Vol 22 (27) ◽  
pp. 15231-15241
Author(s):  
Sheikh I. Hossain ◽  
Neha S. Gandhi ◽  
Zak E. Hughes ◽  
Suvash C. Saha
Keyword(s):  
Gold Nanoparticles ◽  
Lung Surfactant ◽  
Breathing Cycle ◽  
First Line ◽  
Surfactant Monolayers ◽  
Inhaled Nanoparticles

Lung surfactant monolayer’s (acts as the first line barrier for inhaled nanoparticles) components (lipids and peptides) rearrange themselves by the influence of exposed gold nanoparticles at various stages of the breathing cycle.

Surfactant composition and function in lungs of air-breathing fishes

1994 ◽  
Vol 266 (4) ◽  
pp. R1309-R1313 ◽  
Author(s):  
A. W. Smits ◽  
S. Orgeig ◽  
C. B. Daniels
Keyword(s):  
Pulmonary Surfactant ◽  
Total Phospholipid ◽  
Lung Surfactant ◽  
Cholesterol Content ◽  
Lung Lavage ◽  
Air Breathing ◽  
Open Design ◽  
Elevated Cholesterol ◽  
Surfactant Composition ◽  
And Function

Examination of lung washings from primitive air-breathing fishes (ropefish, bichirs, and gar) revealed a lipid-based surfactant with an average disaturated phospholipid-to-total phospholipid ratio five times lower than in mammals. The lung lavage of fishes was exceptionally rich in cholesterol, resulting in average cholesterol-to-phospholipid ratios three times higher, and cholesterol-to-disaturated phospholipid ratios nearly 15 times higher, than those of mammals. Removal of lung surfactant doubled the pressures necessary to initially open the anterior regions of collapsed lungs in all three fish species but had little or no effect on pressures required to fill the lung (i.e., compliance) after the initial opening. The elevated cholesterol content found in pulmonary surfactant of these fishes is consistent with such findings in other ectotherms, suggesting that the proportional elevation of cholesterol may serve to stabilize the fluidity of the lung surfactant over broader temperature ranges. The influence of surfactant on lung opening pressures rather than on compliance contrasts with that seen in mammals and supports an "antiglue" role of pulmonary surfactant in the simpler open-design lungs of lower vertebrates.

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