Evaluation of a small flat rectangular therapeutic ultrasonic transducer intended for intravascular use

Delivery of miR-654-5p via SonoVue Microbubble Ultrasound Inhibits Proliferation, Migration, and Invasion of Vascular Smooth Muscle Cells and Arterial Thrombosis and Stenosis through Targeting TCF21

Background

Abnormal proliferation of vascular smooth muscle cells (VSMCs) is an important cause of vascular stenosis. The study explored the mechanism of inhibition of vascular stenosis through the molecular mechanism of smooth muscle cell phenotype transformation.

Methods

Coronary heart disease-related genes were screened by bioinformatics, and the target genes of miR-654-5p were predicted by dual-luciferase method and immunofluorescence method. miR-654-5p mimic stimulation and transfection of TCF21 and MTAP into cells. SonoVue microbubble sonication was used to deliver miR-654-5p into cells. Cell proliferation, migration, and invasion were detected by CCK-8, wound scratch, and Transwell. HE and IHC staining were performed to study the effect of miR-654-5p delivery via SonoVue microbubble ultrasound on vessel stenosis in a model of arterial injury. Gene expression was determined by qRT-PCR and WB.

Results

TCF21 and MTAP were predicted as the target genes of miR-654-5p. Cytokines induced smooth muscle cell proliferation, migration, and invasion and promoted miR-654-5p downregulation; noticeably, downregulated miR-654-5p was positively associated with the cell proliferation and migration. Overexpression of TCF21 promoted proliferation, invasion, and migration, and mimic reversed such effects. miR-654-5p overexpression delivered by SonoVue microbubble ultrasound inhibited proliferation, migration, and invasion of cells. Moreover, in arterial injury model, we found that SonoVue microbubble ultrasound transmitted miR-654-5p into the arterial wall to inhibit arterial thrombosis and stenosis, while TCF21 was inhibited.

Conclusion

Ultrasound delivery of miR-654-5p via SonoVue microbubbles was able to inhibit arterial thrombosis and stenosis by targeting TCF21.

Multifunctional pathology-mapping theranostic nanoplatforms for US/MR imaging and ultrasound therapy of atherosclerosis

Atherosclerotic thrombosis is the leading cause of most life-threatening cardiovascular diseases (CVDs), particularly as a result of rupture or erosion of vulnerable plaques. Rupture or erosion-prone plaques are quite different in cellular composition and immunopathology, requiring different treatment strategies. The current imaging technology cannot distinguish the types of vulnerable plaques, and thus empirical treatment is still applied to all without a tailored and precise treatment. Herein, we propose a novel strategy called "Multifunctional Pathology-mapping Theranostic Nanoplatform (MPmTN)" for the tailored treatment of plaques based on the pathological classification. MPmTNs are made up of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), containing contrast imaging materials Fe₃O₄ and perfluoropentane (PFP), and coated with specific plaque-targeted peptides PP1 and cyclic RGD. The PFP encapsulated inside the MPmTN can undergo a phase change from nanodroplets to gas microbubbles under therapeutic ultrasound (TUS) exposure. The acoustic and biological effects induced by TUS and disruption of microbubbles may further promote therapeutic effects. Hypothetically, MPmTN NPs can target the rupture-prone plaque via the binding of PP1 to class A scavenger receptors (SR-A) on macrophages, induce the apoptosis due to TUS exposure and thus reduce the chronic soakage of inflammatory cells. The MPmTN NPs can also target the erosion-prone plaque through the binding of cRGD to glycoprotein (GP) IIb/IIIa on activated platelets and promote platelet disaggregation under TUS exposure. Therefore, MPmTNs may work as a multifunctional pathology-mapping therapeutic agent. Our in vitro results show that the MPmTN with PP1 and cRGD peptides had a high binding affinity both for activated macrophages and blood clots. Under TUS exposure, the MPmTN could effectively induce macrophage apoptosis, destroy thrombus and exhibit good imaging properties for ultrasound (US) and MRI. In apoE^-/- mice, MPmTNs can selectively accumulate at the plaque site and reduce the T₂-weighted signal. The apoptosis of macrophages and disaggregation of activated platelets on the plaques were also confirmed in vivo. In summary, this study provides a potential strategy for a tailored treatment of vulnerable plaques based on their pathological nature and a multimodal imaging tool for the risk stratification and assessment of therapeutic efficacy.

SR-A-Targeted Phase-Transition Nanoparticles for the Detection and Treatment of Atherosclerotic Vulnerable Plaques

Atherosclerosis is a major cause of sudden death and myocardial infarction, instigated by unstable plaques. Thus, the early detection of unstable plaques and corresponding treatment can improve the prognosis and reduce mortality. In this study, we describe a protocol for the preparation of nanoparticles (NPs) combined with the phase transitional material perfluorohexane (PFH) and with dextran sulfate (DS) targeting class A scavenger receptors (SR-A) for the diagnosis and treatment of atherosclerotic vulnerable plaques. The results showed that the Fe-PFH-poly(lactic- co-glycolic acid) (PLGA)/chitosan (CS)-DS NPs were fabricated successfully, with the ability to undergo phase transition by low-intensity focused ultrasound (LIFU) irradiation to achieve ultrasound imaging; a high carrier rate of Fe₃O₄ had a good negative enhancement effect on magnetic resonance imaging (MRI). The NPs had a high binding affinity for activated macrophages and could be endocytosed by the macrophages and notably induced apoptosis under LIFU irradiation by an acoustic droplet vaporization effect in vitro. Furthermore, in an ex vivo atherosclerotic plaque model of apolipoprotein E knockout (KO) (apoE^-/-) mice induced by high cholesterol, the NPs selectively accumulated at the sites of SR-A expressed on the activated macrophages of the aortic region. This result was also confirmed by MRI in vivo, where the NPs could be targeted to the aortic plaque and reduced the T₂* signal. The LIFU-induced phase transition could lead to the apoptosis of macrophages on plaques in vivo. In summary, Fe-PFH-PLGA/CS-DS NPs may be applied as multimodal and multifunctional probes and are expected to enable the specific diagnosis and targeted therapy of vulnerable plaques.