Composition of alveolar surfactant changes with training in humans

Doyle, Ian; Morton, S; Crockett, Alan; Barr, Heather A.; Davidson, Kate G.; Jones, Meril; Jones, Michael E.; Nicholas, Terence E.

doi:10.1046/j.1440-1843.2000.00251.x

Cited by 10 publications

(5 citation statements)

References 33 publications

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“…It has previously been reported that surfactant cholesterol increases rapidly with oleic acidinduced acute lung injury and is elevated in alveolar proteinosis (44). However, alveolar cholesterol also increases rapidly with exercise and these increases are more evident in fit individuals (45). It is known that cholesterol can interfere with the ability of DPPC-containing films to attain high surface pressures on the Langmuir balance, but at low concentrations this sterol has no effect on tensiometric behavior of surfactant on the captive bubble (46).…”

Section: Discussionmentioning

confidence: 94%

Effect of Acute Lung Injury on Structure and Function of Pulmonary Surfactant Films

Panda¹,

Nag²,

Harbottle³

et al. 2004

Am J Respir Cell Mol Biol

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The structural and functional alterations in pulmonary surfactant that occur during acute lung injury were studied using rat lung surfactant large aggregates (LA) isolated from normal nonventilated lungs (N), and from standard ventilated (V) and injuriously ventilated (IV) excised lungs. N lungs inflated significantly better than IV lungs, with V lungs intermediate. Although IV LA phosphatidylcholine levels were unchanged, cholesterol and protein were elevated. V LA exhibited PC/cholesterol and PC/protein ratios intermediate between N and IV. In contrast to total cholesterol and protein levels, these ratios were not significantly different from IV LA. N and V LA, but not IV LA, adsorbed rapidly and were able to generate surface pressures (pi) near 70 mN/m during surface area reduction at 37 degrees C on a captive bubble tensiometer. Langmuir-Wilhelmy surface balance studies at 23 degrees C showed N LA films consistently attained pi approaching 70 mN/m during ten compression-expansion cycles. IV films were less effective and failed to achieve high pi consistently after the sixth cycle. V films were intermediate. Epifluorescence studies revealed compression of adsorbed N LA films formed well-defined liquid-condensed (LC) domains, but fewer, smaller domains were observed with IV films and, to a lesser extent, V films. Atomic force microscopy on Langmuir-Blodgett N films transferred at pi = 30 mN/m showed high, well-defined LC domains. IV films showed thinner, intermediate height, possibly fluid domains, which contain large numbers of small higher domains with heights corresponding to LC domains. V films were intermediate. We conclude that acute lung injury induced by hyperventilation, and to a lesser extent standard ventilation, of excised lungs alters surfactant surface activity and the ability of natural surfactant to form surface structures at the air-water interface.

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Section: Discussionmentioning

confidence: 94%

Effect of Acute Lung Injury on Structure and Function of Pulmonary Surfactant Films

Panda¹,

Nag²,

Harbottle³

et al. 2004

Am J Respir Cell Mol Biol

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“…SP-A protein levels are increased in the serum, plasma and sputum of smokers (Kida et al, 1997;Nomori et al, 1998;Mazur et al, 2011), providing another rationale for the proposed beneficial effects of smoking or nicotine consumption in preventing COVID-19 (Farsalinos et al, 2020a). Furthermore, the composition of surfactant highly significant changes rapidly with exercise in a manner related to fitness and training (Doyle et al, 1994(Doyle et al, , 2000. In line, there is an inverse association between serum SP-D and body mass index (Zhao et al, 2007), and moreover inverse association with human obesity (Sorensen et al, 2006).…”

Section: Discussionmentioning

confidence: 96%

Severity of Coronavirus Disease 2019 (COVID-19): Does Surfactant Matter?

Weiskirchen

2020

Front. Microbiol.

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“…Significantly, a clear relationship exists between the subtypes obtained ex vivo and pulmonary physiology. ,,,, First, newborns are devoid of SA at birth, and these accumulate during the first few hours of respiration. , Second, studies with either radiolabelled or stable isotopes in either neonatal or adult lungs demonstrate a metabolic relationship in which the label first incorporates into LA and follows into the SA fraction. , Third, in adulthood, the relative levels of LA and SA are relatively constant, with the lighter subtypes accounting for a third to a half of the surfactant lipid depending on the species. Fourth, under various physiological conditions, including lung injuries, exercise, hyperventilation, and ischemia:reperfusion, the relative proportions of the subtypes change. ,− Specifically, increased relative amounts of SA are observed in lavage fluid with ARDS …”

Section: What Do Physiological and Pathophysiological Studies Teach U...mentioning

confidence: 99%

“…730 Rapid changes in the disaturated PC:cholesterol ratio have been noted with alterations in total lung volume and the rate of breathing. 108,566,686,731 The source of the increased cholesterol or the manner by which alveolar cholesterol is rapidly decreased are not apparent, although macrophages could be involved. Recent evidence indicates the ABC lipid transporters are important in controlling pulmonary cholesterol homeostasis.…”

Section: Notable Deficiencies In Our Current Appreciation Of Pulmonar...mentioning

confidence: 99%

“…Interestingly, although most of the cholesterol in rat surfactant is derived from serum lipoproteins, there are suggestions that lung-derived cholesterol can affect alveolar cholesterol when liver lipoprotein production is impaired . Rapid changes in the disaturated PC:cholesterol ratio have been noted with alterations in total lung volume and the rate of breathing. ,,, The source of the increased cholesterol or the manner by which alveolar cholesterol is rapidly decreased are not apparent, although macrophages could be involved. Recent evidence indicates the ABC lipid transporters are important in controlling pulmonary cholesterol homeostasis …”

Section: Perspectives and Future Considerationsmentioning

confidence: 99%

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Pulmonary Surfactant: A Mighty Thin Film

Possmayer,

Zuo,

Veldhuizen

et al. 2023

Chem. Rev.

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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 adsorptiondriven 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 compressiondriven 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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Composition of alveolar surfactant changes with training in humans

Abstract: We conclude that training markedly alters the composition of alveolar surfactant both at rest and with exercise; the physiological significance of these changes remains to be determined.

Cited by 10 publications

References 33 publications

Effect of Acute Lung Injury on Structure and Function of Pulmonary Surfactant Films

Effect of Acute Lung Injury on Structure and Function of Pulmonary Surfactant Films

Severity of Coronavirus Disease 2019 (COVID-19): Does Surfactant Matter?

Pulmonary Surfactant: A Mighty Thin Film

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