AJP - Lung Cellular and Molecular Physiology, Vol 259, Issue 2 1-12, Copyright © 1990 by American Physiological Society

ARTICLES

Clearance and recycling of pulmonary surfactant

J. R. Wright
Cardiovascular Research Institute, University of California, San Francisco 94143.

In a steady state the rate of secretion of pulmonary surfactant lipids and proteins into the alveolar airspace must be balanced by the rate of removal. Several potential pathways for clearance have been identified including uptake by alveolar type II cells, which also synthesize and secrete surfactant components, uptake by other epithelial cells, and internalization by alveolar macrophages. A small amount of surfactant moves up the airways and through the epithelium-endothelium barrier into the blood. Some of the surfactant lipids and proteins that are cleared from the alveolar airspace appear to be "recycled" in that they appear in the lamellar body, a surfactant secretory granule found in the type II cell. Some surfactant lipids are degraded, probably intracellularly, and the degradation products are reutilized to synthesize new lipids. Several factors have been shown to affect internalization by the type II cell and/or alveolar clearance including the surfactant proteins, lipids, and known stimuli of surfactant secretion. Surfactant proteins may be involved in regulating pool size by modulating both secretion rates and uptake rates, possibly by a receptor-mediated process, although such receptors have not yet been identified or isolated. Clearance of surfactant lipids from the alveolar airspace is more rapid than clearance from the whole lung, and these two processes may be regulated by different factors. Elucidation of the factors that fine tune the balance between synthesis, secretion, and clearance of the lipid and protein components of surfactant awaits further investigation.

This article has been cited by other articles:

				D. Jain, C. Dodia, A. B. Fisher, and S. R. Bates Pathways for clearance of surfactant protein A from the lung Am J Physiol Lung Cell Mol Physiol, December 1, 2005; 289(6): L1011 - L1018. [Abstract] [Full Text] [PDF]

				D. L. H. Poelma, L. J. Zimmermann, W. A. van Cappellen, J. J. Haitsma, B. Lachmann, and J. F. van Iwaarden Distinct effects of SP-B and SP-C on the uptake of surfactant-like liposomes by alveolar cells in vivo and in vitro Am J Physiol Lung Cell Mol Physiol, November 1, 2004; 287(5): L1056 - L1065. [Abstract] [Full Text] [PDF]

				B Muller, H Garn, and R Hochscheid Impaired recycling of surfactant-like liposomes in type II pneumocytes from injured lungs Thorax, February 1, 2003; 58(2): 127 - 134. [Abstract] [Full Text] [PDF]

				T. A. Russo, L. A. Bartholomew, B. A. Davidson, J. D. Helinski, U. B. Carlino, P. R. Knight III, M. F. Beers, E. N. Atochina, R. H. Notter, and B. A. Holm Total extracellular surfactant is increased but abnormal in a rat model of gram-negative bacterial pneumonia Am J Physiol Lung Cell Mol Physiol, September 1, 2002; 283(3): L655 - L663. [Abstract] [Full Text] [PDF]

				J. F. Seymour and J. J. Presneill Pulmonary Alveolar Proteinosis: Progress in the First 44 Years Am. J. Respir. Crit. Care Med., July 15, 2002; 166(2): 215 - 235. [Abstract] [Full Text] [PDF]

				O. Gurel, M. Ikegami, Z. C. Chroneos, and A. H. Jobe Macrophage and type II cell catabolism of SP-A and saturated phosphatidylcholine in mouse lungs Am J Physiol Lung Cell Mol Physiol, June 1, 2001; 280(6): L1266 - L1272. [Abstract] [Full Text] [PDF]

				J. Kattwinkel, B. T. Bloom, P. Delmore, C. Glick, D. Brown, S. Lopez, L. Willett, E. A. Egan, M. Conaway, and J. Patrie High-Versus Low-Threshold Surfactant Retreatment For Neonatal Respiratory Distress Syndrome Pediatrics, August 1, 2000; 106(2): 282 - 288. [Abstract] [Full Text]

				J. Savov, J. R. Wright, and S. L. Young Incorporation of biotinylated SP-A into rat lung surfactant layer, type II cells, and Clara cells Am J Physiol Lung Cell Mol Physiol, July 1, 2000; 279(1): L118 - L126. [Abstract] [Full Text] [PDF]

				E. D. Rider, M. Ikegami, K. E. Pinkerton, J. L. Peake, and A. H. Jobe Lysosomes from rabbit type II cells catabolize surfactant lipids Am J Physiol Lung Cell Mol Physiol, January 1, 2000; 278(1): L68 - L74. [Abstract] [Full Text] [PDF]

				W. Z. Martini, D. L. Chinkes, R. E. Barrow, E. D. Murphey, and R. R. Wolfe Lung surfactant kinetics in conscious pigs Am J Physiol Endocrinol Metab, July 1, 1999; 277(1): E187 - E195. [Abstract] [Full Text] [PDF]

				J. A. Reed, M. Ikegami, E. R. Cianciolo, W. Lu, P. S. Cho, W. Hull, A. H. Jobe, and J. A. Whitsett Aerosolized GM-CSF ameliorates pulmonary alveolar proteinosis in GM-CSF-deficient mice Am J Physiol Lung Cell Mol Physiol, April 1, 1999; 276(4): L556 - L563. [Abstract] [Full Text] [PDF]

				H. Clark, L. Allen, E. Collins, F. Barr, L. Dobbs, G. Putz, J. Goerke, and S. Hawgood Localization of a candidate surfactant convertase to type II cells, macrophages, and surfactant subfractions Am J Physiol Lung Cell Mol Physiol, March 1, 1999; 276(3): L452 - L458. [Abstract] [Full Text] [PDF]

				J. F. Seymour, C. G. Begley, U. Dirksen, J. J. Presneill, N. A. Nicola, P. E. Moore, O. D. Schoch, P. vanAsperen, B. Roth, S. Burdach, et al. Attenuated Hematopoietic Response to Granulocyte-Macrophage Colony-Stimulating Factor in Patients With Acquired Pulmonary Alveolar Proteinosis Blood, October 15, 1998; 92(8): 2657 - 2667. [Abstract] [Full Text] [PDF]

				D. Halpern, O. E. Jensen, and J. B. Grotberg A theoretical study of surfactant and liquid delivery into the lung J Appl Physiol, July 1, 1998; 85(1): 333 - 352. [Abstract] [Full Text] [PDF]

				N. J. Gross, R. Veldhuizen, F. Possmayer, and R. Dhand Surfactant convertase action is not essential for surfactant film formation Am J Physiol Lung Cell Mol Physiol, November 1, 1997; 273(5): L907 - L912. [Abstract] [Full Text] [PDF]

				M. Ikegami, A. H. Jobe, J. A. H. Reed, and J. A. Whitsett Surfactant metabolic consequences of overexpression of GM-CSF in the epithelium of GM-CSF-deficient mice Am J Physiol Lung Cell Mol Physiol, October 1, 1997; 273(4): L709 - L714. [Abstract] [Full Text] [PDF]

				S. Lin, H. T. Akinbi, J. S. Breslin, and T. E. Weaver Structural Requirements for Targeting of Surfactant Protein B (SP-B) to Secretory Granules in Vitro and in Vivo J. Biol. Chem., August 16, 1996; 271(33): 19689 - 19695. [Abstract] [Full Text] [PDF]

				J. L. Carroll Jr., D. M. McCoy, S. E. McGowan, R. G. Salome, A. J. Ryan, and R. K. Mallampalli Pulmonary-specific expression of tumor necrosis factor-alpha alters surfactant lipid metabolism Am J Physiol Lung Cell Mol Physiol, April 1, 2002; 282(4): L735 - L742. [Abstract] [Full Text] [PDF]