Low-energy ultrasound exposure of the streptokinase molecule may enhance but also attenuate its fibrinolytic properties

Ultrasound-enhanced tissue plasminogen activator thrombolysis in an in vitro porcine clot model

“…Härdig et al [45] measured a 31.2% enhancement of streptokinase thrombolysis in human whole blood clots exposed to 1.0-MHz pulsed ultrasound with a duty cycle of 10% and a spatial average, temporal average intensity of 0.5 W/cm 2 . These investigators also noted a decrease in ultrasound enhancement of streptokinase thrombolysis at higher exposure level (above 1 W/ cm 2 ).…”

Advancements in Catheter-Directed Ultrasound-Accelerated Thrombolysis

“…[25][26][27][28][29][30][31][32][33][34][35][36][37][38] According to Blinc et al, 25 the degree of thrombolysis depends on the plasminogen activator concentration, the intensity of ultrasound waves, the duty cycles, and the frequency. A successful thrombolytic effect has been reported for urokinase, 25,26,28 rtPA, 25,48 tPA, 27 reteplase, 35 and streptokinase 25,28,34,36 at intensities ranging from 0.125 to 4 W/cm 2 . The lytic effect of streptokinase and reteplase, however, disappeared at intensity levels of $4 W/cm 2 , indicating that the balance between ultrasound waves and pharmacological treatment is crucial.…”

“…The lytic effect of streptokinase and reteplase, however, disappeared at intensity levels of $4 W/cm 2 , indicating that the balance between ultrasound waves and pharmacological treatment is crucial. [34][35][36] In addition, Soltani et al 90 demonstrated that ultrasound with a frequency of 1 MHz and intensities of 2.5 to 3.1 W/cm 2 had no statistically significant effect on the enzymatic activity of the plasminogen activators urokinase, reteplase, alteplase, and streptokinase. Nevertheless, only limited data is available on the ideal concentrations of plasminogen activators necessary for optimal ultrasoundenhanced thrombolysis.…”

Advanced drug delivery systems for antithrombotic agents

“…PEG-gelatin nanocarriers also prolonged the circulation of tPA and released it in an ultrasound-responsive fashion, improving recanalization of occlusive clots in rabbits. 29 Further refinements of the ELIP approach are warranted, as potent ultrasound may inactivate PAs 30 and cause vascular damage. Some clots may not be amenable to this approach due to unknown location or risk of hemorrhage.…”