Clotting factors added to fibroblast cultures. Their action on glycosaminoglycans and other parameters.

To monolayer cultures of embryonic rat fibroblasts in the proliferative and stationary phase of growth there were given: thrombin, fibrinogen or fibrin supernatant, respectively. Their effects on cell proliferation, glucose consumption and glycosaminoglycans were recorded and observed to be more pronounced in serum-depleted and confluent cultures. Thrombin in serum-supplemented cultures was nearly ineffective. In serum-free stationary cultures glucose consumption, GAG concentration and, above all, hyaluronic acid were increased. Fibrinogen stimulated the metabolism of stationary fibroblasts (glucose, GAG, particularly hyaluronic acid) more strongly in serum-depleted medium. A number of protease inhibitors were ineffective in abolishing the fibrinogen action pointing to the efficacy of the intact fibrinogen molecule. The supernatant of the fibrinogen-thrombin-reaction, separated after 3 hours, likewise increased glucose consumption, GAG and hyaluronic acid concentration possibly due to effects of the fibrinopeptides A or B. However, contamination of fibrinogen with other active compounds cannot be excluded as yet. Surprisingly, fibrin generated on the fibroblast monolayer did not stimulate the cells. Therefore fixation of the active compounds of the fibrin supernatant (fibrinopeptides) during the process of fibrin polymerization has to be assumed. According to these observations thrombin, fibrinogen and components of the fibrin supernatant contribute to the increase of hyaluronic acid and cell activation in the oedematous phase of inflammation at sites free from fresh-formed fibrin.