title: Characterization of the lower respiratory tract inflammation of nonsmoking individuals with interstitial lung disease associated with chronic inhalation of inorganic dusts.
abstract: The pneumoconioses, interstitial lung disorders resulting from the inhalation of inorganic dusts, are associated with chronic inflammatory processes in the lower respiratory tract. To characterize these inflammatory processes in relation to the pathogenesis of these disorders, we studied 39 nonsmoking individuals with long-term occupational exposures to inorganic dust and functional evidence of interstitial disease (asbestosis, n = 18; coal workers' pneumoconiosis, n = 15; silicosis, n = 6). In all 3 disorders, the inflammation was dominated by alveolar macrophages. Because a common feature of these interstitial lung diseases is concurrent injury and fibrosis of alveolar walls, we assessed whether these alveolar macrophages were spontaneously releasing mediators capable of giving rise to these changes. Alveolar macrophages from the study population were spontaneously releasing increased amounts of superoxide anion and hydrogen peroxide (both p less than 0.01 compared to normals), oxidants capable of injuring lung parenchymal cells. The alveolar macrophages were also spontaneously releasing significantly increased amounts of fibronectin and alveolar macrophage-derived growth factor (both p less than 0.01 compared to normals), mediators that act synergistically to signal fibroblast replication. Taken together, these findings define a major role for the alveolar macrophage in mediating the alveolar wall injury and fibrosis that characterize the common pneumoconioses and suggest that the alveolar macrophage is an important "target" for developing strategies designed to prevent loss of lung function in these individuals.
authors.affiliation: Pulmonary Branch. National Heart, Lung, and Blood Institute, Bethesda, MD 20892.
authors.forename: W N
authors.initials: WN
authors.lastname: Rom
authors.forename: P B
authors.initials: PB
authors.lastname: Bitterman
authors.forename: S I
authors.initials: SI
authors.lastname: Rennard
authors.forename: A
authors.initials: A
authors.lastname: Cantin
authors.forename: R G
authors.initials: RG
authors.lastname: Crystal
mesh_terms: D000328:Adult; D001195:Asbestosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000378:metabolism; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000378:metabolism; D005260:Female; D005353:Fibronectins / Q000378:metabolism; D005710:Gallium Radioisotopes; D006133:Growth Substances / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D008168:Lung / Q000000981:diagnostic imaging; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010455:Peptides; D011009:Pneumoconiosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000378:metabolism*; D011650:Pulmonary Alveoli / Q000378:metabolism; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000378:metabolism*; D011877:Radionuclide Imaging; D012829:Silicosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000378:metabolism; D012907:Smoking; D013481:Superoxides / Q000378:metabolism
chemical_list: D005353:Fibronectins; D005710:Gallium Radioisotopes; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; C042586:alveolar macrophage growth factor; D013481:Superoxides; D006861:Hydrogen Peroxide