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Silica‐exposed macrophages release a growth‐promoting activity for type II pneumocytes
Author(s) -
Melloni Boris,
Lesur Olivier,
Cantin André,
Bégin Raymond
Publication year - 1993
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.53.3.327
Subject(s) - in vitro , macrophage , in vivo , biology , cell growth , alveolar macrophage , cell culture , microbiology and biotechnology , biochemistry , genetics
This study addresses the hypothesis that silica‐ activated alveolar macrophages could release soluble factors stimulating type II cell proliferation. Macrophages from control sheep were exposed or not in vitro to silica, aluminum‐treated silica (Si‐Al), or titanium dioxide (TiO2). In addition, macrophages from a model of chronic silica‐exposed sheep were studied. Supernatants from unstimulated macrophages were found to double basal type II cell DNA synthesis. Alveolar macrophage‐conditioned media (AMCM) collected from cells exposed in vitro to silica induced an additional growth‐promoting activity for type II cells. Supernatants from Si‐Al‐ or TiO2 dust‐exposed alveolar macrophages had the same effects as unstimulated AMCM. In addition, AMCM from in vivo silicotic sheep cells also contained elevated levels of type II cell mitogenic activity. These results suggest that in vitro as in vivo, silica‐activated macrophages produce a type II cell growth factor(s) for type II epithelial cells.