VASCULAR CELL ATTACHMENT AND PROCOAGULANT ACTIVITY ON METAL-ALLOYS

The attachment and growth of vascular smooth muscle cells on biomateri als used as components of devices implanted in the vascular space may influence the biocompatibility of such materials. The nature of the ma terials may affect the attachment and/or the activation of these cells procoagulant responses. Therefore, the main objective of this study w as to measure the strength of adhesion of these vascular cells to pote ntial biomaterials (titanium, zirconium alloys, and stainless steel) b y exposing them to a range of shear stresses (50-300 dyn cm(-2)) in a parallel plate flow chamber. The procoagulant responses of the cells a ere evaluated by measuring the tissue factor (TF) activity promoted b y the different materials under flow conditions. The materials support ed distinctly different levels of initial cell adhesion in static cult ure. However, the fraction of adherent cells did not decline significa ntly with incrementally increasing shear stress within the range teste d. TF expression, as measured by factor Xa (FXa) production, was mater ial-dependent. For example, cells cultured on Ti1313 exhibited more FX a production (13.2 nhl 10(-5) cells) than Ti1313(DH) (8.5 nM 10(-5) ce lls) or stainless steel (2 nM 10(-5) cells). Thus, our studies indicat e that the level of adhesion, strength of attachment and the expressio n of procoagulant activity of adherent vascular cells depend strongly on the nature of the underlying biomaterial.