[Secretory products of macrophages stimulate arterial smooth muscle cell migration in vitro]

Stimulation by macrophage secretory products of the migration of arterial smooth muscle cells was studied in vitro with a modified system. Round cell colonies were formed by plating subcultured smooth muscle cells into the middle wells of agarose gels. Following irradiation (1500 rads) and refeeding with test medium, cell migration was observed by measuring the increase in surface area of cell colonies at specific time intervals. The cell colonies expanded under the agarose gels with an increment of approximately 10.6 mm2 per day when exposed to macrophage conditioned medium, and the average increase in surface area of the colonies was approximately 5.7 and 8.6 mm2 per day when exposed to platelet-deficient serum and whole blood serum, respectively. The results indicate that macrophages may contribute to atheromatous plaque formation by stimulating smooth muscle cell migration into the intima in the case of arterial damage due to hyperlipemia or other causes.