EGT protocols: the role of electroporation based techniques, hyaluronidase and pH effects in the permeabilization of tissue fibers

N. OLAIZ; E. SIGNORI; F. MAGLIETTI; SOBA, ALEJANDRO; L. GUERRA; C. SUAREZ; L. COLOMBO; P. TURJANSKY; S. MICHINSKI ; G. MARSHALL

Bochum

Congreso; COST Symposium on Electroporation and Biomedical Applications and MC Meeting; 2013

During the last decade, pulsed electric fields were explored in local tumor treatment based upon electroporation, a technique in which cell membrane integrity is disturbed creating pores across it. Different approaches are electrochemotherapy (ECT), irreversible electroporation (IRE) and electrogenetherapy (EGT). ECT combines reversible electroporation with non-permeant anticancer drugs to potentiate their entry into the cell. IRE is a technique that kills the cells leaving intact main tissue structures. EGT has great potential as a non-viral gene-delivery system as it achieves the introduction of plasmids or oligonucleotides to the cell. EGT is nevertheless also associated with some tissue damage that must be minimized. Therefore, optimal EGT requires a compromise between maximum transgene expression and minimal tissue damage. McMahon et al. 2001 showed that plasmid gene transfer efficiency in tissue fibers such as muscle can be significantly improved by the application of EGT to the muscle following injection of bovine hyaluronidase and plasmid DNA. With hyaluronidase pretreatment, the area of damage was more limited but was still severe in areas near electrodes with a concomitant loss of transfected tissue fibers and reduction in expression. In a different context, it is shown that extreme pH changes occur in tissues when EGT pulses are applied, in spite of the presence of natural buffers (Maglietti et al. 2012). The aim of this work is to study the relationship between pH and tissue damage observed during the application of EGT-derived treatments in order to optimize pulse handling through in vivo and in silico modeling. Ways to optimize the EGT/ hyaluronidase protocol are suggested.