Characteristics of coronary smooth muscle cells and adventitial fibroblasts.

Background—Recent findings suggesting the involvement of adventitial cells in coronary repair have raised questions regarding the phenotypic “plasticity” of medial smooth muscle cells (SMCs). Accordingly, the aims of the present study were to examine the characteristics of coronary medial and adventitial cells and to compare the responses of coronary and noncoronary SMCs to stimulation. Methods and Results—Enzymatically isolated coronary SMCs (human and porcine) were distinct from noncoronary SMCs, showing poor adhesion and spreading, as well as lower proliferation, collagen synthesis, and LDL degradation. Several extracellular matrix components (Matrigel, collagen I and IV, laminin, vitronectin, fibronectin) or growth factors (epidermal growth factor, platelet-derived growth factor-BB, insulin growth factor-1, interleukin-1α) failed to augment the adhesion or proliferation of coronary SMCs to the levels observed in noncoronary SMCs. Unlike coronary SMCs, coronary fibroblasts demonstrated high adhesion, p...