Faculty Member Islamic Azad University- Tabriz Branch Tabriz, Azarbayjan-e Sharqi, Iran
Background: When vascular smooth muscle cells proliferate and migrate, especially in the tunica intima, it is referred to as intimal hyperplasia. Neointimal hyperplasia result in neoatherosclerosis formation and plaque rupture leads to arterial thromboembolism.
Aims: This study's objective was to examine the effects of combined Altretamine- mediated sonoporation therapy and beta particle- mediated brachytherapy on the regression of neointimal hyperplasia in an animal model. Diagnostic B- mode ultrasound is integrated with therapeutic system with the purpose of increasing safety.
Methods: Endothelial balloon catheter denudation of the abdominal aorta of New Zealand white rabbits was performed. Neointimal hyperplasia development in all of the rabbits' arteries was confirmed by histopathologic analysis. The treatment group underwent intravenous lipid- based, encapsulated altretamine nanoparticles (10mg/Kg)- mediated extracorporeal pulsed low- level focused ultrasound (I= 24 W/cm2, F= 1.1 MHz, PD= 150 ms) sonoporation therapy, accompanied by catheter- based Rhenium 186- mediated beta particle brachytherapy (186 Re, 25 Gy), guided by concurrent B- mode ultrasound imaging.
Results: Targeting aortic stenosis with combination therapy, under ultrasound guidance was possible and appeared safe. Additionally, the treatment group's mean values for arterial mean wall thickness (MWT), percentage of luminal cross-sectional area of stenosis (LAS%), and smooth muscle hyperplasia cells density were significantly lower than other groups (p < 0.05), according to sonographic and pathological results.
Conclusion(s): Regression of neointimal hyperplasia, can be induced by the anti-proliferative effect of brachytherapy combined with the enhanced anti-proliferative effect of altretamine, induced by the enhanced sonoporation effect of focused ultrasound, brought on by the inertial cavitation effect of collapsed capsules. Reduced smooth muscle hyperplasia cells in the tunica intima could be the mechanism.