The effects of thrombin on bovine aortic endothelial and smooth muscle cells

Recent evidence suggests that thrombin interacts with various cell types, stimulating cellular proliferation and protein and prostanoid production. To further delineate its role in vascular healing, we have studied the effects of thrombin on proliferation and matrix production by the cells of the vessel wall. The addition of thrombin (1 unit/ml) to cultures of bovine aortic smooth muscle cells resulted in an increase in cell proliferation (p less than 0.01) and number (p less than 0.03), whereas in cultures of bovine aortic endothelial cells thrombin produced a decrease in cell proliferation (p less than 0.01) and number (p less than 0.02). Thrombin also altered matrix composition in cultures of these cells. In both bovine aortic endothelial cells and bovine aortic smooth muscle cell cultures grown in the presence of thrombin, total protein content was significantly increased when compared to controls (p less than 0.03). In bovine aortic endothelial cell cultures the addition of thrombin resulted in a decrease in collagen content (p less than 0.01) and an increase in sulfated glycosaminoglycan content (p less than 0.02). In contrast, in bovine aortic smooth muscle cell cultures thrombin resulted in an increase in collagen content (p less than 0.03), whereas glycosaminoglycan content was unaffected. These findings suggest that thrombin may significantly influence vascular healing and function by altering cell number and matrix composition.