COMPARTMENTALIZED COCULTURE OF PORCINE ARTERIAL ENDOTHELIAL AND SMOOTH-MUSCLE CELLS ON A MICROPOROUS MEMBRANE

Endothelial and smooth muscle cells were harvested from porcine pulmon ary arteries and grown to two passages from primary culture in serum-c ontaining medium. Thereafter, the cells were plated on the opposite si des of a microporous poly(ethylene terephthalate) membrane and cultiva ted in a chemically defined, serum-free medium. The membrane with pore s of 1 mu m diameter allowed the passage of molecules and the extensio n of cell processes, while maintaining separate homogeneous cell popul ations. Pores of 3 mu m diameter permitted the crossing of smooth musc le cells through the membrane, The coating of the polymer with constit uents of the extracellular matrix optimized cell adhesion, Morphologic al analysis of the model showed typical cobblestone pattern and ultras tructure of endothelial cells, which lost rapidly the expression of vo n Willebrand factor hut kept that of angiotensin-converting enzyme. Sm ooth muscle cells were spindle shaped and specific alpha-actin was rev ealed by immunochemistry and quantitated by enzyme-linked immunosorben t assay (ELISA). Their ultrastructure featured an intermediate contrac tile-synthetic phenotype. Permeability studies to different molecules showed a marked reduction of the albumin clearance. Finally, in cocult ure in the presence of endothelial cells, the smooth muscle cells prol iferation was increased, whereas it was not the case in autologous coc ultures. In conclusion, such a coculture model may help to a better un derstanding of the interactions between endothelial and smooth muscle cells that may be important in the pathogenesis of vascular diseases.