SUPERNATANTS FROM QUARTZ DUST TREATED HUMAN MACROPHAGES STIMULATE CELL-PROLIFERATION OF DIFFERENT HUMAN LUNG-CELLS AS WELL AS COLLAGEN-SYNTHESIS OF HUMAN-DIPLOID LUNG FIBROBLASTS IN-VITRO

Silicosis is a chronic lung disease, which is caused by inhalation of silica-containing dusts, leading to pulmonary fibrosis. Alveolar macro phages play a key-role in defence against these particles entering the lung. As a result of phagocytosis, the macrophages release mediators, which are involved in various processes of inflammation and immunolog ical defence mechanisms. We established an in-vitro test system compos ed of human macrophages, human pneumocyte type II cells (line A-549), human diploid lung fibroblasts (line Wi38) and human tracheobronchial epithelial cells (line BEAS-2B). With this model, we were able to stud y the influence of various cytokines, produced by the macrophages, on cell proliferation and collagen synthesis (only fibroblasts) of the ce lls in our test-system. In this report, we will summarize data obtaine d from our in-vitro test system on two cytokines, which are thought to be important in pathogenesis of lung fibrosis: insulin-like growth fa ctor-1 (IGF-1) and transforming growth factor-beta (TGF-beta). (C) 199 8 Elsevier Science Ireland Ltd. All rights reserved.