Platelet membrane coated r-SAK to improve thrombolytic efficacy by targeting thrombus

Abstract Background Thrombolytic therapy is one of the most effective treatments to achieve rapid thrombus clearance and recanalization of blocked vessels in thrombotic diseases. However, the application of thrombolytic strategy has been limited due to unsatisfied thrombolytic efficacy, relatively higher bleeding complications, and consequently restricted indications.[1] With the development of nanotechnology and biotechnology, platelet membrane nanoparticles have been developed to enable the targeted delivery of thrombolytic agents to local thrombus sites.[2] Recombinant staphylokinase (r-SAK) is a third-generation thrombolytic agent produced by genetic engineering technology. In this study, platelet membrane coated r-SAK (PLT-r-SAK) was constructed, and its thrombolytic efficacy was evaluated in in-vitro and in-vivo experiments. Purpose We aimed to construct a thrombus-targeting agent of PLT-r-SAK and investigate its thrombolytic efficacy. Methods PLT-r-SAK was prepared by encapsulating r-SAK into platelet membrane vesicles using a membrane extrusion method. An in-vitro thrombolytic experiment was performed to examine the thrombolytic efficacy of PLT-r-SAK, and a totally occluded femoral artery thrombosis model of rabbit was developed to evaluate the in-vivo thrombolytic efficacy of PLT-r-SAK. The changes in femoral artery pressure were adopted to assess the vessel opening status. Besides, the effect of the antiplatelet drugs on the thrombolytic efficacy of PLT-r-SAK was explored. Finally, near-infrared fluorescence imaging system was used to verify the thrombus-targeting effect of PLT-r-SAK. Results PLT-r-SAK was firstly constructed, which exhibited a uniformly dispersed spherical morphology with a diameter of 185.8 ± 1.5 nm and a zeta potential of -26.1 ± 0.8 mV. In the in-vitro animal experiment, the thrombolysis rate of PLT-r-SAK was significantly higher than that of the same (low) dose and 4-fold (high) dose r-SAK (Figure 1a, 1b). In the in-vivo experiment, the initial recanalization time of PLT-r-SAK was significantly shorter than that of the low dose and high dose r-SAK, and the duration of the reperfusion time of PLT-r-SAK was prolonged compared to low dose and high dose r-SAK (Figure 1c). Another in-vitro experiment showed that the increased thrombolysis rate of PLT-r-SAK could be inhibited by platelet poor plasma (PPP) from aspirin- and ticagrelor-treated patients. Finally, both the in-vitro and in-vivo near-infrared fluorescence imaging showed significantly higher radiant efficiency in the PLT-r-SAK group as compared to the NS group (Figure 2). Conclusions Platelet membrane coating significantly improves the thrombolytic efficacy of r-SAK, which is related to the thrombus-targeting activity of the platelet membrane and can be inhibited by aspirin- and ticagrelor-treated plasma.Thrombolytic efficacy of PLT-r-SAKThrombus-targeting evidence of PLT-r-SAK