Cellular fibrinolytic activity of human alveolar bone

Abstract The fibrinolytic activity of normal alveolar bone cells was studied in 7 biopsies from the mandibular third molar region by the fibrin slide technique. It was shown that the activity of the loose connective tissue type of bone marrow in all biopsies was very high even when low incubation temperatures (25°–30°C) were used. Lysis was present even after 5 min of incubation and pronounced after 30 min. Only tissue activator activity was recorded and no plasmin activity. The fibrinolytic activity was probably related to the osteoblasts and the endothelial cells of the blood vessels. The importance of these findings for the explanation of the high content of both labile and stable tissue activators in alveolar bone is discussed.