title: Transcutaneous ultrasound augments naked DNA transfection of skeletal muscle.
abstract: This study was designed to test the hypothesis that transcutaneous ultrasound (US) exposure may augment the transfection efficiency and biological outcome associated with nonviral DNA gene transfer. Hindlimb muscles of New Zealand White rabbits were transfected with the reporter plasmid pCMV-beta, with or without US exposure. Optimization studies employed US exposure at various frequencies, mechanical indices, duty cycles, durations of exposure, and exposure time points. Based on these results, we explored the effect of US exposure on nonviral gene transfer of vascular endothelial growth factor (VEGF, phVEGF165) to promote neovascularization of ischemic hindlimbs. Ultrasound at 1 MHz, 100 W/cm(2), 6% duty cycle, and 5 minutes exposure time, applied immediately following DNA injection, was found to be the most effective among the settings tested, increasing beta-galactosidase expression approximately 20 fold. Compared with US exposure alone, or phVEGF165 only, phVEGF165 + US exposure yielded a statistically significant improvement in revascularization, as determined by calf blood pressure ratio, angiographic score, intravascular Doppler blood flow, and capillary/myocyte ratio. These data demonstrate that ultrasound, when applied directly after intramuscular gene transfer, significantly increases transfection efficiency in vivo. The biological significance of this finding was confirmed by augmented limb perfusion in response to US exposure and naked VEGF DNA.
authors.affiliation: Department of Cardiovascular Research, St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02135, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Schratzberger
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Krainin
authors.forename: Gabriele
authors.initials: G
authors.lastname: Schratzberger
authors.forename: Marcy
authors.initials: M
authors.lastname: Silver
authors.forename: Hong
authors.initials: H
authors.lastname: Ma
authors.forename: Marianne
authors.initials: M
authors.lastname: Kearney
authors.forename: Robert F
authors.initials: RF
authors.lastname: Zuk
authors.forename: Axel F
authors.initials: AF
authors.lastname: Brisken
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Losordo
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Isner
mesh_terms: D000818:Animals; D002196:Capillaries / Q000378:metabolism; D004247:DNA; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D015316:Genetic Therapy / Q000379:methods*; D006439:Hemodynamics; D007511:Ischemia; D008297:Male; D032342:Muscle Cells / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D009389:Neovascularization, Pathologic; D010957:Plasmids / Q000378:metabolism; D011817:Rabbits; D014162:Transfection; D014465:Ultrasonics; D014652:Vascular Diseases / Q000628:therapy; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D004247:DNA; D001616:beta-Galactosidase