Aerosolized endotoxin is immediately bound by pulmonary surfactant protein D in vivo

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE

卷:1454

Article

van Rozendaal, BAWM ; van de Lest, CHA ; van Eijk, M ; van Golde, LMG ; Voorhout, WF ; van Helden, HPM ; Haagsman, HP

关键词: surfactant protein D (SP-D);    lung;    lipopolysaccharide;    collectin;    alveolar macrophage;    host defense;   

DOI  :  10.1016/S0925-4439(99)00042-3

来源: Elsevier

【 摘 要 】

Collectins are carbohydrate binding proteins that are implicated in innate host defense. The lung collectins, surfactant proteins A and D (SP-A and SP-D), bind a variety of pathogens in vitro and influence phagocytosis by alveolar macrophages. In this report we show that SP-D binds endotoxin (lipopolysaccharide, LPS) in vivo in a rat model of acute respiratory distress syndrome (ARDS). Intratracheal aerosolization of LPS in rats resulted in the typical features of human ARDS. Total amounts of SP-D, as well as the carbohydrate binding properties of SP-D were measured in lung lavage as a function of time. The amount of SP-D did not change during 24 h. Interestingly, SP-D in lung lavage isolated from rats during the first 2 h after LPS treatment, was not able to bind to carbohydrate. Further analysis revealed that the carbohydrate binding sites of SP-D were occupied by LPS, suggesting that SP-D is an LPS scavenging molecule in vivo. Electron microscopic analysis indicated that, 1 h after LPS aerosolization, aggregates of SP-D with LPS were found in lysosomal structures in alveolar macrophages. We conclude that the lung collectin SP-D binds inhaled endotoxin in vivo, which may help to protect the lung from endotoxin-induced disease. (C) 1999 Elsevier Science B.V. All rights reserved.

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