HETEROGENEOUS SMOOTH-MUSCLE CELL-POPULATION DERIVED FROM SMALL AND LARGER ARTERIES

Vascular lesion formations in such disease states as hypertension and atherosclerosis occur in a district-specific manner. Large conduit and small resistance arteries play district-specific roles in the regulat ion of organ perfusion. Using a culture method, we studied the morphol ogy and growth of smooth muscle cells derived from small arteries (S-S MCs, less than 90 mu m in internal diameter) and from larger arteries (L-SMCs, ranging from 800 to 900 mu m) of the rat mesenteric arterial bed. S-SMCs showed a hill-and-valley pattern, whereas L-SMCs showed sh eet or whorl formation. The majority of S-SMCs were smaller, bipolar-s haped; in contrast, the majority of L-SMCs were larger, polygonal-shap ed. Actin fibers within S-SMCs were oriented in a bipolar manner from the nuclei, whereas those within L-SMCs had a radial appearance. [H-3] Thymidine incorporation induced by serum, platelet-derived growth fact or-AB (PDGF), or mechanical stretch was greater in S- vs L-SMCs. The p opulation doubling time measured after the addition of serum or PDGF w as shorter in S- vs L-SMCs. Thus, distinct morphological and growth ph enotypes of SMCs exist in small and larger arteries of the same vascul ar bed. (C) 1998 Academic Press.