Center for Research in Biological Chemistry and Molecular Materials (CiQUS), University of Santiago de Compostela, 15705, Santiago de Compostela, Spain.
Translational Stroke Laboratory Group (TREAT), Clinical Neurosciences Research Laboratory (LINC), Health Research Institute of Santiago de Compostela (IDIS), 15706, Santiago de Compostela, Spain.
J Nanobiotechnology. 2024 Jan 3;22(1):10. doi: 10.1186/s12951-023-02206-5.
Intravenous administration of fibrinolytic drugs, such as recombinant tissue plasminogen activator (rtPA) is the standard treatment of acute thrombotic diseases. However, current fibrinolytics exhibit limited clinical efficacy because of their short plasma half-lives and risk of hemorrhagic transformations. Platelet membrane-based nanocarriers have received increasing attention for ischemic stroke therapies, as they have natural thrombus-targeting activity, can prolong half-life of the fibrinolytic therapy, and reduce side effects. In this study we have gone further in developing platelet-derived nanocarriers (defined as cellsomes) to encapsulate and protect rtPA from degradation. Following lyophilization and characterization, their formulation properties, biocompatibility, therapeutic effect, and risk of hemorrhages were later investigated in a thromboembolic model of stroke in mice.
Cellsomes of 200 nm size and loaded with rtPA were generated from membrane fragments of human platelets. The lyophilization process did not influence the nanocarrier size distribution, morphology, and colloidal stability conferring particle preservation and long-term storage. Encapsulated rtPA in cellsomes and administered as a single bolus showed to be as effective as a continuous clinical perfusion of free rtPA at equal concentration, without increasing the risk of hemorrhagic transformations or provoking an inflammatory response.
This study provides evidence for the safe and effective use of lyophilized biomimetic platelet-derived nanomedicine for precise thrombolytic treatment of acute ischemic stroke. In addition, this new nanoformulation could simplify the clinical use of rtPA as a single bolus, being easier and less time-consuming in an emergency setting than a treatment perfusion, particularly in stroke patients. We have successfully addressed one of the main barriers to drug application and commercialization, the long-term storage of nanomedicines, overcoming the potential chemical and physical instabilities of nanomedicines when stored in an aqueous buffer.
静脉内给予纤维蛋白溶解药物，如重组组织型纤溶酶原激活剂（rtPA），是急性血栓性疾病的标准治疗方法。然而，由于其血浆半衰期短和出血转化的风险，目前的纤维蛋白溶解剂的临床疗效有限。基于血小板膜的纳米载体因其具有天然的血栓靶向活性、可以延长纤维蛋白溶解治疗的半衰期以及减少副作用而受到越来越多的关注，可用于缺血性脑卒中的治疗。在这项研究中，我们进一步开发了血小板衍生的纳米载体（定义为细胞体）来包裹和保护 rtPA 免受降解。经过冻干和表征，随后在小鼠血栓栓塞性脑卒中模型中研究了其制剂特性、生物相容性、治疗效果和出血风险。
200nm 大小的负载 rtPA 的细胞体是由人血小板的膜片段产生的。冻干过程不影响纳米载体的粒径分布、形态和胶体稳定性，从而保证了颗粒的保存和长期储存。细胞体内包裹的 rtPA 作为单次推注给药与以相同浓度连续临床输注游离 rtPA 一样有效，而不会增加出血转化的风险或引发炎症反应。
这项研究为冻干仿生血小板衍生纳米医学在精确溶栓治疗急性缺血性脑卒中的安全有效应用提供了证据。此外，这种新的纳米制剂可以简化 rtPA 的临床应用，作为单次推注给药比治疗输注更简单，在紧急情况下比输注更耗时，特别是在脑卒中患者中。我们成功地解决了药物应用和商业化的一个主要障碍，即纳米药物的长期储存问题，克服了纳米药物在储存在水缓冲液中时可能存在的化学和物理不稳定性。
