Enhancement of Tenecteplase Thrombolytic Actions Ex Vivo and In Vivo by Deoxyribonuclease I.

BACKGROUND: We aimed to investigate the phenomenon of thrombolysis resistance in tenecteplase and its underlying causes and evaluate whether DNase-1 (deoxyribonuclease I) targeting neutrophil extracellular traps (NETs) could enhance the thrombolytic efficiency of tenecteplase. METHODS: Fresh thrombi were retrieved from 25 patients with acute ischemic stroke via endovascular thrombectomy, and 50 artificial blood clots were generated by recalcifying whole blood from healthy donors for ex vivo thrombolysis experiments by tenecteplase±DNase-1. Fibrinolytic resistance was analyzed via histology and scanning electron microscope. Thrombolytic rates were calculated. NETs were observed with immunofluorescence colocalization of NET markers. In vivo experiment was performed in mice with photothrombotic stroke, to evaluate the effects of tenecteplase+DNase-1 versus tenecteplase on cerebral blood flow, infarct volume, and neurological deficits. RESULTS: The NET-rich outer shell remained after tenecteplase thrombolysis in thrombi and blood clots. Additive DNase-1 enhanced the thrombolytic efficiency of tenecteplase, resulting in faster thrombolytic rates and lower weights of thrombus (31% versus 48%; P<0.001) and clot (32% versus 53%; P<0.001) at 60 minutes. DNase-1 also enhanced the thrombolytic efficiency of tenecteplase in mice with photothrombotic stroke, resulting in more significantly restored cerebral blood flow at 60 minutes (66.0% versus 27.5%; P<0.001), and smaller infarct volume (11.2% versus 14.6% of the whole brain volume; P<0.001) and less severe neurological deficits (median Longa score 1 versus 3; P=0.003) at 24 hours. CONCLUSIONS: The shell structure of a thrombus, particularly the NETs, may play an important role in fibrinolytic resistance to tenecteplase. Additive DNase-1 may enhance the thrombolytic efficiency of tenecteplase.