Biosyntheses of interstitial collagens and fibronectin by porcine aorta smooth muscle cells. Modulation by low-molecular-weight heparin fragments

The effect of low-molecular-weight heparin fragments (CY222) on the biosynthetic phenotype of porcine aortic smooth muscle cells (SMC) was investigated in vitro on overconfluent cell cultures. Addition of increasing concentrations of CY222 to the culture medium of early passage SMC resulted in a dose-dependent decrease of type III to type I collagen ratio without change in total collagen biosynthesis. In the same range of concentrations CY222 did not affect the biosynthesis of fibronectin. However, heparin fragments decreased the proportion of the freshly synthesized pericellular form of fibronectin with a concomitant increase of neosynthesized intracellular fibronectin, indicating an inhibitory effect of CY222 on fibronectin secretion. Our results demonstrate that the biosynthetic phenotype of SMC in vitro can be modulated by low-molecular-weight heparin fragments and confirm also that interactions between cells and extracellular matrix molecules can modify the biosynthetic pattern of mesenchymal cells.