In vivo NMR imaging evaluation of efficiency and toxicity of gene electrotransfer in rat muscle

Abstract

In vivo gene electrotransfer (ET) is a simple method of gene delivery in various tissues relying on the injection of plasmid DNA followed by application of electric pulses. Noninvasive tools are needed to evaluate the ET efficiency and the resulting tissue damages. In this study, we performed ET of rat tibialis muscle after injection of either a plasmid coding for luciferase or a contrast agent (CA) detected by using magnetic resonance imaging (MRI). Plasmid expression and CA intracellular trapped quantity were compared throughout the electric field intensity range 0-300 V/cm. Although the CA trapped quantity reflects only the electropermeabilization step, both measurements were correlated. MRI measurements gave easy access to tridimensional visualization of the labelled zones where the CA has been injected and the applied electric field had a value allowing permeabilization. We also performed MRI measurements of the water transverse relaxation time T2 as an indicator of tissue modification, and tested whether another CA specific for necrosis could be used to detect muscle necrosis at high electric field intensity. In conclusion, MRI measurements may bring multiparametric information upon the efficiency and tissue toxicity of an ET protocol by using a simple and safe CA.

MR Imaging to Assess Immediate Response to Irreversible Electroporation for Targeted Ablation of Liver Tissues: Preclinical Feasibility Studies in a Rodent Model

“…While histologic measurements were highly correlated with intraprocedural rigorously investigate the mechanism or mechanisms that may have lead to these aforementioned differences. membranes, during which muscle tissue edema was visualized as hyperintense regions on T2-weighted images ( 4,29 ).…”

Electric field-mediated transport of plasmid DNA in tumor interstitium in vivo

“…Unfortunately, increasing the energy of the applied pulses also increases their adverse effects on tissues. Therefore, the higher energy pulses, which may result in an irreversible cell membrane modification [41,42], are unlikely to be suitable for clinical use.…”

Electrotransfer into Skeletal Muscle for Protein Expression

“…It has been also shown that muscle necrosis increases with the cumulative duration of the pulses [Mathiesen, 1999]. Recently, an in vivo NMR imaging system has been developed to visualize and evaluate the electropermeabilized zones during electric field-mediated drug or gene delivery [Leroy-Willig et al, 2005] and therefore assess more precisely the efficiency and toxicity of different protocols.…”

“…The procedure itself (needle injection and cell permeabilisation by high electric field) may induce an inflammatory response [Leroy-Willig et al, 2005], but this inflammation has been shown to be mostly plasmid DNA-dependent [Hartikka et al, 2001]. Plasmid DNA stimulates the immune system and leads to inflammation via the hypomethylated bacterial CpG sequences, via the antibiotic resistance genes and promoter elements containing prokaryotic immunostimulatory sequences, and possibly even via contamination during the plasmid purification process, with LPS for example [McMahon et al, 1998].…”