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lamellar bodies
Monday 26 November 2007
Lamellar bodies are lysosomal-derived organelles of alveolar type II cells (type 2 pneumocytes).
Lamellar bodies appear in the cytoplasm of type 2 pneumocytes at about 20 weeks gestation. These lamellar bodies are secreted by exocytosis into the surface water layer lining the alveolar airspace, where the surfactant forms a meshwork of tubular myelin.
This alveolar surfactant can be both broken down by macrophages and/or reabsorbed into the lamellar structures of type II alveolar cells. Up to 90% of surfactant phosphatidylcholine is recycled from the alveolar space in the newborn.
The lipid transporter ABCA3 targets surfactant phospholipids to lamellar bodies.
References
Edwards V, Cutz E, Viero S, Moore AM, Nogee L. Ultrastructure of lamellar bodies in congenital surfactant deficiency. Ultrastruct Pathol. 2005 Nov-Dec;29(6):503-9. PMID: 16316951
