Nitrophorin 2, a factor IX(a)-directed anticoagulant, inhibits arterial thrombosis without impairing haemostasis

作者：Mizurini Daniella M; Francischetti Ivo M B; Andersen John F; Monteiro Robson Q^*

来源：Thrombosis and Haemostasis, 2010, 104(6): 1116-1123.

DOI：10.1160/TH10.1160/TH10-03-0186

• Animal models
• arterial thrombosis
• coagulation inhibitors
• haemostasis
• nitrophorin

Nitrophorin 2 (NP2) is a 20 kDa lipocalin identified in the salivary gland of the blood sucking insect, Rhodnius prolixus. It functions as a potent inhibitor of the intrinsic pathway of coagulation upon binding to factor IX (FIX) or FIXa. Herein we have investigated the in vivo antithrombotic properties of NP2. Surface plasmon resonance assays demonstrated that NP2 binds to rat FIX and FIXa with high affinities (K(D) = 43 and 47 nM, respectively), and prolongs the aPTT without affecting the PT. In order to evaluate NP2 antithrombotic effects in vivo two distinct models of thrombosis in rats were carried out. In the rose Bengal/laser induced injury model of arterial thrombosis, NP2 increased the carotid artery occlusion time by approximate to 35 and approximate to 155%, at doses of 8 and 80 mu g/kg, respectively. NP2 also inhibited thrombus formation in an arterio-venous shunt model, showing approximate to 60% reduction at 400 mu g/kg (i.v. administration). The antithrombotic effect lasted for up to 48 hours after a single i.v. dose. Notably, effective doses of NP2 did not increase the blood loss as evaluated by tail-transection model. In conclusion, NP2 is a potent and long-lasting inhibitor of arterial thrombosis with minor effects on haemostasis. It might be regarded as a potential agent for the treatment of human cardiovascular diseases.

• 出版日期2010-12-10