Thrombus-Targeted Nanocarrier Attenuates Bleeding Complications Associated with Conventional Thrombolytic Therapy
Thrombus-Targeted Nanocarrier Attenuates Bleeding Complications Associated with Conventional Thrombolytic Therapy
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DOI：
10.1007/s11095-013-1011-x
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发表时间：
2013-06-01
影响因子：
3.7
通讯作者：
Ahsan, Fakhrul
中科院分区：
文献类型：
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作者：
Absar, Shahriar;Nahar, Kamrun;Ahsan, Fakhrul
为验证载血栓特异性组织纤溶酶原激活剂（tPA）纳米载体增强溶栓效果和减轻出血并发症的假设，制备了一系列聚乙二醇化和非聚乙二醇化tPA脂质体，并在其表面修饰与活化血小板上表达的GPIIb/IIIa结合的纤维蛋白原γ链肽序列（CQQHHLGGAKQAGDV）。对所有制剂的物理性质、稳定性和体外释放曲线进行表征。采用终点目测法、纤维蛋白琼脂平板法和人血凝块溶解法检测载tPA脂质体的溶栓活性。通过研究荧光肽脂质体与活化血小板的结合来评价肽修饰脂质体的血栓特异性。分别在健康大鼠和下腔静脉血栓形成大鼠模型中评价了药物动力学和溶栓效果。聚乙二醇化和非聚乙二醇化肽修饰脂质体均显示出良好的物理特性和胶体稳定性。制剂在体外表现出初始突释（30分钟内40-50%），随后是tPA的连续释放（24小时内80-90%）。与天然tPA相比，包封的tPA保留> 90%的纤溶活性。含有tPA的肽接枝脂质体表现出与活化的血小板结合的亲和力。非聚乙二醇化和聚乙二醇化脂质体的tPA半衰期分别从7分钟延长至103分钟和141分钟。与天然tPA相比，脂质体-tPA引起凝块溶解增加35%，但产生的循环纤维蛋白原消耗减少4.3倍。tPA装载归巢肽接枝脂质体表现出增强的溶栓活性，降低出血风险。
To test the hypothesis that thrombus-specific tissue plasminogen activator (tPA)-loaded nanocarriers enhance thrombolytic efficacy and attenuate hemorrhagic complications.A series of pegylated and non-pegylated tPA-loaded liposomes were prepared and their surfaces were decorated with the peptide sequence (CQQHHLGGAKQAGDV) of fibrinogen gamma-chain that binds with GPIIb/IIIa expressed on activated platelets. All formulations were characterized for physical properties, stability and in vitro release profile. The thrombolytic activities of tPA-loaded liposomes were tested by visual end-point detection, fibrin agar-plate and human blood clot-lysis assays. The thrombus-specificity of the peptide-modified-liposomes was evaluated by studying the binding of fluorescent peptide-liposomes with activated platelets. The pharmacokinetic profile and thrombolytic efficacy were evaluated in healthy rats and an inferior vena-cava rat model of thrombosis, respectively.Both pegylated and non-pegylated peptide-modified-liposomes showed favorable physical characteristics and colloidal stability. Formulations exhibited an initial burst release (40-50% in 30 min) followed by a continuous release of tPA (80-90% in 24 h) in vitro. Encapsulated tPA retained > 90% fibrinolytic activity as compared to that of native tPA. Peptide-grafted-liposomes containing tPA demonstrated an affinity to bind with activated platelets. The half-life of tPA was extended from 7 to 103 and 141 min for non-pegylated and pegylated liposomes, respectively. Compared to native tPA, liposomal-tPA caused a 35% increase in clot-lysis, but produced a 4.3-fold less depletion of circulating fibrinogen.tPA-loaded homing-peptide-grafted-liposomes demonstrate enhanced thrombolytic activity with reduced hemorrhagic risk.