Inhibition of Neointimal Proliferation in Balloon-Injured Arteries Using Non-Anticoagulant Heparin-Carrying Polystyrene

Non-anticoagulant heparin-carrying polystyrene (NAC-HCPS) has a higher activity to inhibit proliferation and migration of smooth muscle cells (SMCs) than heparin (Hep), periodate-oxidized (IO4-) Hep, and periodate-oxidized alkaline-degraded low molecular weight (IO4-LMW-) Hep. Less than 10 microg/ml of NAC-HCPS significantly inhibited the proliferation and migration of SMCs in vitro, while over 10-fold higher concentrations of Hep, IO4-Hep, and IO4-LMW-Hep were required to obtain the same inhibition. On the other hand, neointimal growth (intimal cross-section area and intimal cross-section area/medial cross-section area ratio) in vivo following vascular injury 28 days after balloon denudation in a rat carotid artery was substantially inhibited with high dose of intravenous administration (total 30 mg) of respectively IO4-Hep, IO4-LMW-Hep, and NAC-HCPS. A low-dose (total 10 mg) administration of IO4-Hep and IO4-LMW-Hep did not prevent the neointimal growth when compared with the control; only NAC-HCPS (total 10 mg) was able to significantly inhibit the neointimal. Thus, NAC-HCPS has a more-than 10-fold larger activity to inhibit SMC activities such as proliferation and migration in vitro, when comparing with Hep, IO4-Hep, and IO4-LMW-Hep; NAC-HCPS also prevents neointimal growth in vivo at lower doses.