title: Low-frequency ultrasound increases non-viral gene transfer to the mouse lung.
abstract: The aim of the study was to assess if low-frequency ultrasound (US), in the range of 30-35 kHz, increases non-viral gene transfer to the mouse lung. US is greatly attenuated in the lung due to large energy losses at the air/tissue interfaces. The advantages of low-frequency US, compared with high-frequency US are: (i) increased cavitation (responsible for the formation of transient pores in the cell membrane) and (ii) reduced energy losses during lung penetration. Cationic lipid GL67/plasmid DNA (pDNA), polyethylenimine (PEI)/pDNA and naked pDNA were delivered via intranasal instillation and the animals were then exposed to US (sonoporation) at 0.07 or 0.1 MPa for 10 min. Under these conditions, US did not enhance GL67 or PEI-mediated transfection. It did, however, increase naked pDNA gene transfer by approximately 4 folds. Importantly, this was achieved in the absence of microbubbles, which are crucial for the commonly used high-frequency (1 MHz) sonoporation but may not be able to withstand nebulization in a clinically relevant setup. Lung hemorrhage was also assessed and shown to increase with US pressure in a dose-dependent manner. We have thus, established that low-frequency US can enhance lung gene transfer with naked pDNA and this enhancement is more effective than the previously reported 1 MHz US.
authors.affiliation: Department of Gene Therapy, National Heart and Lung Institute, Faculty of Medicine, Imperial College, London, UK.
authors.forename: Stefania
authors.initials: S
authors.lastname: Xenariou
authors.forename: Hai-Dong
authors.initials: HD
authors.lastname: Liang
authors.forename: Uta
authors.initials: U
authors.lastname: Griesenbach
authors.forename: Jie
authors.initials: J
authors.lastname: Zhu
authors.forename: Raymond
authors.initials: R
authors.lastname: Farley
authors.forename: Lucinda
authors.initials: L
authors.lastname: Somerton
authors.forename: Charanjit
authors.initials: C
authors.lastname: Singh
authors.forename: Peter K
authors.initials: PK
authors.lastname: Jeffery
authors.forename: Ronald K
authors.initials: RK
authors.lastname: Scheule
authors.forename: Seng H
authors.initials: SH
authors.lastname: Cheng
authors.forename: Duncan M
authors.initials: DM
authors.lastname: Geddes
authors.forename: Martin
authors.initials: M
authors.lastname: Blomley
authors.forename: Eric W F W
authors.initials: EW
authors.lastname: Alton
mesh_terms: D000818:Animals; D018014:Gene Transfer Techniques; D008168:Lung / Q000737:chemistry / Q000821:virology*; D051379:Mice; D011094:Polyethyleneimine / Q000737:chemistry*; D014162:Transfection / Q000379:methods* / Q000706:statistics & numerical data; D014465:Ultrasonics
chemical_list: D011094:Polyethyleneimine