Migration of human vascular endothelial and smooth muscle cells

Migration of endothelial and smooth muscle cells was studied in vitro by measuring the increase in surface area at specific time intervals of confluent cell colonies advancing under agarose gels that contained both Morgan's medium 199 and various types of sera. First passage cultures of endothelial cells or 3 to 6 passage smooth muscle cells were plated into wells punched in agarose gels, at a seeding density of 50,000 cells per well. At zero time the size of the cell colonies was 35.4 sq mm ± standard error 0.1. Irradiation (1500 rad) did not affect the expansion of the cell colonies although ³H-thymidine uptake was inhibited. Endothelial cells migrated under the agarose gels concentrically as contiguous sheets. When exposed to either 20% platelet-poor plasma serum, platelet-rich plasma serum, or whole blood serum, the average increase in surface area was approximately 9 sq mm per day. In contrast, arterial smooth muscle cell colonies expanded with an increment of approximately 9 sq mm per day when exposed to 10% platelet-poor plasma serum but 12 sq mm per day when exposed to 10% platelet-rich plasma serum (P < 0.001). Platelet factors also had stimulatory effect on the migration of venous smooth muscle cells. Cytochalasin B, dibutyryl cyclic AMP, and theophylline inhibited the migration of both endothelial and smooth muscle cells, but the latter responded more to the inhibitory effects of all three agents. It is concluded that in contrast to vascular smooth muscle, endothelial cells do not require platelet factors for migration and are less responsive to specific inhibitors affecting cell movement.