Growth regulation of fibroblasts by thrombin, factor XIII and fibronectin

The stimulation of fibroblast proliferation by thrombin and factor XIII is accompanied by an intracellular increase of cGMP. In contrast fibronectin inhibits the 3H-thymidine uptake of fibroblasts. Pre-treatment of fibroblasts with neuraminidase eliminates the stimulating effect of thrombin completely and induces a shift of the optimum stimulating effect of factor XIII to higher concentrations. It is discussed that thrombin and factor XIII stimulate the proliferation of fibroblasts as growth hormones and regulate in combination with the inhibiting fibronectin the growth of fibroblasts in thrombus organization, wound healing and in the arteriosclerotic vessel wall process.