Response of pulmonary macrophages to hyperoxic pulmonary injury. Acquisition of surface fibronectin and fibrin/ogen and enhanced expression of a fibronectin receptor.

The in vivo acquisition of coagulation plasma proteins on the surface of pulmonary macrophages was studied in guinea pigs breathing 95% oxygen. Fibrin/ogen and fibronectin appeared rapidly and concurrently on the surfaces of macrophages in the bronchoalveolar lavage fluid, which was judged by immunohistologic examination and flow cytometry. Pulmonary macrophages showed a parallel increase in the expression of a surface fibronectin receptor. Hyperoxic lung injury was accompanied by deposition of an extravascular pulmonary matrix of fibronectin and fibrin/ogen and depressed plasma levels of fibronectin. Binding to clot matrix proteins may lead to aggregation and retention of macrophages at sites of acute lung injury as well as alteration of cell function.