title: Contrast imaging and gene delivery through the combined use of novel cationic liposomal microbubbles and ultrasound in rat carotid arteries.
abstract: BACKGROUND
  Lipid-coated cationic microbubbles represent a new class of agents with both diagnostic and therapeutic applications. The main goal of this study was to evaluate the efficiency of gene transfer through the combined use of microbubbles and ultrasound in rat carotid arteries. Furthermore, we assessed whether the cationic liposomal microbubbles could allow long-term enhanced imaging, comparing with SonoVue(®).
  
  
  METHODS
  Normal rat carotid arteries were imaged after intravenous bolus injections of 0.5 ml/kg of two contrast agents (SonoVue(®) and the cationic liposomal microbubbles). Forty Sprague-Dawley rats were divided into 5 groups according to ultrasound parameters and were treated with or without microbubbles. All rats were sacrificed after being transfected for 2 days. The level of protein expression was determined by western blot analysis.
  
  
  RESULTS
  The enhancing time of self-made microbubbles was much longer than that of SonoVue(®) in rat carotid arteries (p < 0.05). The results of the western blot analysis revealed that the expression of SR-BI DNA in the carotid artery was highest in the SR-BI + US/CLM group (p < 0.05).
  
  
  CONCLUSIONS
  These results suggest that the novel cationic liposomal microbubbles enhance image quality over a longer period than does SonoVue(®). Additionally, the combination of ultrasound and this new type of microbubble can act synergistically to increase SR-BI DNA transfection.
authors.affiliation: Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Jiaan
authors.initials: J
authors.lastname: Zhu
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Huang
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
authors.forename: Mengjie
authors.initials: M
authors.lastname: Rui
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Xu
authors.forename: Bing
authors.initials: B
authors.lastname: Hu
keywords: cationic liposomal microbubble; contrast-enhanced ultrasound; gene delivery; microbubbles; rat