重组猪凝血因子Ⅷ的功能鉴定及潜在治疗作用的研究

Functional characterization and therapeutic potential of recombinant porcine factorⅧ

目的评估重组猪凝血因子Ⅷ(recombinant porcine factorⅧ,rpFⅧ)对血友病A型(hemophilia A,HA)伴抑制物患者的潜在治疗作用。方法通过凝血酶酶切、rpFⅧ与血管性血友病因子(von Willebrand factor,VWF)的亲和力、活化部分凝血活酶时间(activated partial thromboplastin time,APTT)及血栓弹力图等方法对rpFⅧ进行了体外活性分析。并对rpFVIII在动物体内外的药效及药代动力学特征进行了评估。结果rpFⅧ可被凝血酶激活。在APTT检测中,相比阴性对照组(105.2 s),rpFⅧ组的凝血时间显著缩短(43.3 s,P<0.05)。在动物实验中,相比模型对照组(43.1 s),rpFⅧ给药组小鼠的血浆在APTT检测中的凝血时间显著缩短(28.8 s,P<0.05);且rpFⅧ与市售药Xyntha(重组人FⅧ)在小鼠体内的血药代谢趋势相似,两者间的各项药代动力学参数相近。在含有FⅧ抑制物的体外药效评价模型中,当以猴血浆(含有抗人FⅧ抗体)作为研究对象时,在各实验条件下,相比Xyntha组,rpFⅧ组的凝血时间均显著缩短(P<0.05);在血栓弹力图实验中,相比阴性对照组与Xyntha组,rpFⅧ组的凝血时间明显缩短(P<0.05);当以HA患者血浆(含有抗人FⅧ抗体)作为研究对象时,相比阴性对照组(患者1血浆:99.2 s,患者2血浆:97.7 s),rpFⅧ组的凝血时间显著缩短(患者1血浆:55.8 s,患者2血浆:43.6 s,P<0.05)。结论rpFⅧ具备良好的生物学活性,在动物及体外实验中均展示出了对伴抑制物HA患者的潜在治疗作用。

Objective Evaluate the potential therapeutic function of recombinant porcine FⅧ(rpFⅧ)in treating hemophilia A(HA)patient with inhibitor.Methods The rpFⅧwas characterized with thrombin activation and affinity binding with humanVWF,activated partial thromboplastin time(APTT)assay and thromboelastogram(TEG).The pharmacokinetic of rpFⅧwas compared with commercial recombinant human FⅧ(rhFⅧ)in FⅧknock⁃out mice.The therapeutic function of rpFⅧhas been tested(ex⁃vivo)in hemophilia A/hemophilia A with inhibitor animal models as well as confirmed using the plasma of hemophilia A patient with inhibitor.Results The biochemical characterization of rpFⅧindicated that it is fully functional.The pharmacokinetic assay demonstrated that the rpFⅧhas similar PK parameters with rhFⅧ.In pharmacodynamic studies,the rpFⅧdemonstrated the ability of normalizing clotting time in bothplasma of hemophilia A and hemophilia A with inhibitor.Similar results have also been confirmed in patient plasma of hemophilia A with inhibitor.Conclusion rpFⅧdemonstratedthe potential therapeutic effects in bothHA animal model and patient plasma with or without inhibitor.