Ultrasonically targeted delivery into endothelial and smooth muscle cells in ex vivo arteries

Abstract

This study tested the hypothesis that ultrasound can target intracellular uptake of drugs into vascular endothelial cells (ECs) at low to intermediate energy and into smooth muscle cells (SMCs) at high energy. Ultrasound-enhanced delivery has been shown to enhance and target intracellular drug and gene delivery in the vasculature to treat cardiovascular disease, but quantitative studies of the delivery process are lacking. Viable ex vivo porcine carotid arteries were placed in a solution containing a model drug, TO-PRO ® -1, and Optison ® microbubbles. Arteries were exposed to ultrasound at 1.1 MHz and acoustic energies of 5.0, 66, or 630 J/cm 2 . Using confocal microscopy and fluorescent labeling of cells, the artery endothelium and media were imaged to determine the localization and to quantify intracellular uptake and cell death. At low to intermediate ultrasound energy, ultrasound was shown to target intracellular delivery into viable cells that represented 9 -24% of exposed ECs. These conditions also typically caused 7 -25% EC death. At high energy, intracellular delivery was targeted to SMCs, which was associated with denuding or death of proximal ECs. This work represents the first known in-depth study to evaluate intracellular uptake into cells in tissue. We conclude that significant intracellular uptake of molecules can be targeted into ECs and SMCs by ultrasound-enhanced delivery suggesting possible applications for treatment of cardivascular diseases and dysfunctions.

A fluorescent chromophore TOTO‐3 as a ‘smart probe’ for the assessment of ultrasound‐mediated local drug delivery in vivo

“…Acoustic cavitation is the formation, oscillation and collapse of gas-filled bubbles in a fluid medium exposed to ultrasound (10), thereby enhancing the permeability of cell membranes through the creation of pores (11). Recently, several groups showed that cavitation can also be used for the intracellular delivery of small molecules (12)(13)(14).…”

Effects of extracellular calcium on cell membrane resealing in sonoporation

“…Many studies have demonstrated that ultrasound (US) can delivery DNA, proteins, and other formulations of molecules of interest into viable cells [1][2][3][4][5][6][7][8]. It has been hypothesized that US energy, often amplified by microbubble activities (e.g.…”

“…Compelling results obtained recently have stimulated great interest in the development of sonoporation applications with exciting possibilities [1][2][3][4][5][6][7][8]. However, progress in the field is hindered by a lack of mechanistic understanding of the sonoporation process and its outcome beyond demonstrations of initial feasibility [20].…”

Enzymatic Single-Chain Antibody Tagging

“…33 Despite the development of a large number of preclinical delivery systems, very few new technologies or materials have entered clinical trials. One hurdle is that regulatory approval requires well-defined products for clinical use.…”