ROLE OF GROWTH-FACTORS IN THE CONTRACTION AND MAINTENANCE OF COLLAGEN LATTICES MADE WITH ARTERIAL SMOOTH-MUSCLE CELLS

The contraction of collagen lattices made with arterial smooth muscle cells was studied in medium MCDB 107 without serum or supplemented with 1% fetal bovine serum, plus insulin, transferrin, and low-density lipoprotein. Under these conditions, smooth muscle cell mitogens including HBGF-1 (aFGF), PDGF, and EGF stimulated contraction. Stimulation by HBGF-1 was more profound than with other factors tested. HBGF-1 stimulation of lattice contraction was blocked by protein synthesis inhibitors, but not by inhibitors of DNA synthesis. Histological observations indicated that HBGF-1 also enhanced the maintenance of healthy cells in the lattice. Taken together, these observations suggest that HBGF-1 stimulates lattice contraction, not by a mitogenic effect, but by stimulating synthesis of specific cellular proteins. Since the greatest effects of HBGF-1 on lattice contraction were seen during the first 72 h following casting, the effects on maintenance of cell viability are probably less important in promoting lattice contraction.