Surfactant protein D. Increased accumulation in silica-induced pulmonary lipoproteinosis.

Abstract

Surfactant protein D (SP-D) (CP4) is a collagenous surfactant-associated carbohydrate binding protein that is synthesized and secreted by alveolar epithelial cells. Previous studies have shown that intratracheal administration of crystalline silica to rats elicits a marked increase in the alveolar accumulation of surfactant lipids and surfactant protein A (SP-A). The authors examined the accumulation of SP-D using this animal model of alveolar proteinosis. Immunoperoxidase localization of SP-D studies at 2 weeks after silica instillation showed intense staining of intra-alveolar exudates, and cytoplasmic staining of hypertrophic type II cells. Immunoelectron microscopy showed that airspace SP-D was specifically associated with granular material, but not tubular myelin or other membranous structures. SP-D was quantified in bronchoalveolar lavage by immunoassay using antibodies specific for SP-D, and by reversephase HPLC after affinity purification of SP-D on maltosyl-agarose. Within 2 weeks after silica instillation, there was a greater than 45-fold increase in lavage SP-D per lung compared with saline controls, including an almost ten-fold increase in the insoluble or surfactant-associated protein. These studies indicate that the extracellular accumulation of SP-D is markedly increased in silica-induced lipoproteinosis, and that SP-D is associated with amorphous components identified by electron microscopy.

• Authors: E Crouch, A Persson, D Chang, D Parghi
• Journal: The American journal of pathology (Am J Pathol) Vol. 139 Issue 4 Pg. 765-76 (Oct 1991) ISSN: 0002-9440 [Print] United States
• PMID: 1656758 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Antibodies
• Glycoproteins
• Pulmonary Surfactant-Associated Protein D
• Pulmonary Surfactants
• Silicon Dioxide

Topics

• Animals
• Antibodies (immunology)
• Bronchoalveolar Lavage Fluid (chemistry)
• Chromatography, High Pressure Liquid
• Epithelium (metabolism, ultrastructure)
• Glycoproteins (analysis, immunology, metabolism)
• Immunoenzyme Techniques
• Lipoid Proteinosis of Urbach and Wiethe (chemically induced, metabolism)
• Lung Diseases (chemically induced, metabolism)
• Microscopy, Electron
• Microscopy, Immunoelectron
• Pulmonary Alveoli (metabolism, ultrastructure)
• Pulmonary Surfactant-Associated Protein D
• Pulmonary Surfactants (analysis, immunology, metabolism)
• Rats
• Rats, Inbred Strains
• Silicon Dioxide