A temporary cardiovascular
stent device by bioabsorbable materials might reduce late
stent thrombosis. A water-soluble amphiphilic
phospholipid polymer bearing
phosphorylcholine groups (
PMB30W) was blended with a high-molecular-weight
poly(l-lactic acid) (PLLA) to reduce unfavorable tissue responses at the surface. The PLLA implants and the
polymer blend (PLLA/
PMB30W) implants were inserted into subcutaneous tissues of rats, the infrarenal aorta of rats, and the internal carotid arteries of rabbits. After 6 months subcutaneous implantation, the PLLA/
PMB30W maintained high density of
phosphorylcholine groups on the surface without a significant bioabsorption. After intravascular implantation, the cross-sectional areas of
polymer tubing with diameters less than 1.6 mm were histomorphometrically measured. Compared to the PLLA tubing, the PLLA/
PMB30W tubing significantly reduced the
thrombus formation during 30 d of implantation. Human peripheral blood mononuclear cells were cultured on the PLLA and the PLLA/
PMB30W to compare inflammatory reactions.
Enzyme-linked
immunosorbent assay quantified substantially decreased proinflammatory
cytokines in the case of the PLLA/
PMB30W. They were almost the same level as the negative controls. Thus, we conclude that the
phosphorylcholine groups could reduce tissue responses significantly both in vivo and in vitro, and the PLLA/
PMB30W is a promising material for preparing temporary cardiovascular
stent devices.