Growth factor modulation of rat pleural mesothelial cell mitogenesis and collagen synthesis. Effects of epidermal growth factor and platelet-derived factor.

This study examined the effects of an epithelial and a mesenchymal growth factor on pleural mesothelial cell proliferation and collagen synthesis, functions that may be important in the response of the pleura to injury. Epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) added singly caused significant increases relative to control in both the uptake of [3H]thymidine into the cellular DNA of subconfluent monolayers and of [3H]proline into collagenase-sensitive protein. Combinations of EGF and PDGF resulted in more than additive increases in proliferation and additive increases in collagen production relative to each factor alone. Media from control and growth factor-stimulated PMC demonstrated no gelatinase or collagenase activity, suggesting that the increase in net collagen production was secondary to enhanced synthesis. These data demonstrate that both epithelial and mesenchymal growth factors can stimulate PMC proliferation and collagen synthesis and that these growth factors have even greater effects when combined, particularly in regard to cellular proliferation. Increases in PMC proliferation and collagen synthesis in response to these growth factors may be important in healing the pleura after injury by a variety of disease processes.