Fibromuscular proliferates induced in vitro using a trans-filter culture system.

A trans-filter co-culture system of vascular smooth muscle cells (SMC) and endothelial cells (EC) is compared with a trans-filter culture of SMC without EC. Explants from the tunica media of rabbit aorta are cultured on one side of a polycarbonate filter with a defined pore size (5 microns). Smooth muscle cells grow out from the media explants and migrate through the filter pores to the other side of the filter, where they proliferate. After 14 days in trans-filter culture, a multilayer resembling "fibromuscular plaques" seen in vivo is formed on the opposite side of the filter. Moreover, the proliferation rate of SMC that have migrated through the filter pores is demonstrated to be similar to that of SMC in intimal lesions induced by balloon catheter injury. In the trans-filter co-culture, a monolayer of endothelial cells (porcine, bovine, or human) is cultivated on one side of the filter. Media explants are placed on the other side. This arrangement mimics the in vivo situation of an arterial vessel wall with endothelium and media separated by a porous lamina. In this co-culture system, the few smooth muscle cells that migrate into the subendothelial space do not form a cell multilayer. A confluent endothelial cell layer is capable of inhibiting the formation of a proliferate in this co-culture system.