Abstract：
Heparin is the most common anticoagulant used in clinical practice but shows some downsides such as short half-life (for the high molecular weight heparin) and secondary effects. On the other hand, its low molecular weight analogue cannot be neutralized with protamine, and therefore cannot be used in some treatments. To address these issues, we conjugated polyethylene glycol (PEG) to heparin reducing end (end-on) via oxime ligation and studied the interactions of the conjugate (Hep-b-PEG) with antithrombin III (AT) and protamine. Isothermal titration calorimetry showed that Hep-b-PEG maintains the affinity to AT. Dynamic light scattering demonstrated that the Hep-b-PEG formed colloidal stable nanocomplexes with protamine instead of large multi-molecular aggregates, associated with heparin side effects. The in vitro (human plasma) and in vivo experiments (Sprague Dawley rats) evidenced an extended half-life and higher anticoagulant activity of the conjugate when compared to unmodified heparin.
摘要：
肝素是临床实践中使用的最常见的抗凝剂，但显示出一些缺点，例如半衰期短（对于高分子量肝素）和副作用。另一方面,它的低分子量类似物不能用鱼精蛋白中和，因此不能用于某些治疗。为了解决这些问题,我们通过肟连接将聚乙二醇（PEG）与肝素还原末端（末端）缀合，并研究了缀合物（Hep-b-PEG）与抗凝血酶III（AT）和鱼精蛋白的相互作用。等温滴定量热法显示Hep-b-PEG保持对AT的亲和力。动态光散射表明Hep-b-PEG与鱼精蛋白形成了胶体稳定的纳米复合物，而不是大的多分子聚集体。与肝素副作用有关。体外(人血浆)和体内实验(SpragueDawley大鼠)证明,与未修饰的肝素相比,缀合物具有延长的半衰期和更高的抗凝血活性。
