Short- and Long-Term Effects of Pulsed Ultrasound Cavitation Therapy of Calcified Valvular Interstitial Cells in Culture

Abstract

Objective: Calcific aortic valve disease advances via increased fibrosis and calcification deposition, leading to progressive narrowing of the outflow tract, left ventricular hypertrophy and cardiac failure. Currently, surgical repair and replacement are the only strategies for intervention. While transcatheter aortic valve replacement offers a less invasive alternative to surgical intervention, implanted bioprosthetic valves have limited durability. Non-invasive ultrasound therapy was shown to not damage normal porcine aortic valve, and successfully reduced stenosis of calcified bioprosthetic valves in vivo, as well as decrease stenosis of native severely calcified aortic stenosis in a first-in-human study. However, critical questions regarding the effect of ultrasound therapy on valvular cells remain. In this study, we aimed to optimize pulsed ultrasound cavitation (PUC) treatment for cell culture studies and evaluate the acute and persistent effects on human valvular interstitial cells (hVICs) in calcifying conditions. Methods: We utilized viability, metabolism and calcification assays as well as mass spectrometry-based proteomics to holistically characterize the effects of PUC treatment in hVICs. Results: hVICs viability and metabolism were not significantly altered as a function of PUC treatment at short- (48 hour) or long-term (21 day) time points. Furthermore, PUC treatment did not increase hVICs calcification in vitro. Proteomic profiling of hVICs showed that PUC treatment had limited persistent changes to protein profiles compared with the acute effects of PUC treatment. Conclusion: These studies suggest that ultrasound therapy, currently limited to very severe aortic stenosis, could be of interest at an earlier stage of the disease.