This Article Figures Only Full Text Full Text (PDF) Online Appendix Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Fujii, H. Articles by Li, R.-K. Search for Related Content PubMed Articles by Fujii, H. Articles by Li, R.-K. Related Collections Related Article

Ultrasound-Targeted Gene Delivery Induces Angiogenesis After a Myocardial Infarction in Mice

Hiroko Fujii, MD, PhD^_*, Zhuo Sun, MD^_*, Shu-Hong Li, MD, MSc^_*, Jun Wu, MD^_*, Shafie Fazel, MD, PhD^_*, Richard D. Weisel, MD^_*, Harry Rakowski, MD, Jonathan Lindner, MD, Ren-Ke Li, MD, PhD^_*,_*

^_* Division of Cardiovascular Surgery, Toronto General Research Institute and Toronto General Hospital, Toronto, Ontario, Canada
Division of Cardiology, Toronto General Research Institute and Toronto General Hospital, Toronto, Ontario, Canada
Cardiovascular Division, Oregon Health and Science University, Portland, Oregon

^_* Reprint requests and correspondence: Dr. Ren-Ke Li, Toronto General Research Institute, MaRS Centre, Toronto Medical Discovery Tower, Room 3-702, 101 College Street, Toronto, Ontario, Canada M5G 1L7 (Email: renkeli{at}uhnres.utoronto.ca).

Objectives: This study evaluated the capacity of ultrasound-targeted microbubble destruction (UTMD) to deliver angiogenic genes, improve perfusion, and recruit progenitor cells after a myocardial infarction (MI) in mice.

Background: Angiogenic gene therapy after an MI may become a clinically relevant approach to improve the engraftment of implanted cells if targeted delivery can be accomplished noninvasively. The UTMD technique uses myocardial contrast echocardiography to target plasmid gene delivery to the myocardium and features low toxicity, limited immunogenicity, and the potential for repeated application.

Methods: Empty plasmids (control group) or those containing genes for vascular endothelial growth factor (VEGF), stem cell factor (SCF), or green fluorescent protein (to visualize gene delivery) were incubated with perflutren lipid microbubbles. The microbubble-deoxyribonucleic acid mixture was injected intravenously into C57BL/6 mice at 7 days after coronary artery ligation (MI). The UTMD technique facilitated transgene release into the myocardium. Twenty-one days after MI, myocardial perfusion and function were assessed by contrast echocardiography. Protein expression was quantified by Western blot and enzyme-linked immunosorbent assay. Flow cytometry quantified progenitor cell recruitment to the heart. Blood vessel density was evaluated immunohistochemically.

Results: Green fluorescent protein expression in the infarcted myocardium demonstrated gene delivery. Myocardial VEGF and SCF levels increased significantly in the respective groups (p < 0.05). The physiologic impact of VEGF and SCF gene delivery was confirmed by increased myocardial recruitment of VEGF receptor 2– and SCF receptor (c-kit)–expressing cells, respectively (p < 0.05). Consequently, capillary and arteriolar density (Factor VIII and alpha-smooth muscle actin staining), myocardial perfusion, and cardiac function were all enhanced (p < 0.01 relative to control group) in recipients of VEGF or SCF.

Conclusions: Noninvasive UTMD successfully delivered VEGF and SCF genes into the infarcted heart, increased vascular density, and improved myocardial perfusion and ventricular function. The UTMD technique may be an ideal method for noninvasive, repeated gene delivery after an MI.

Key Words: angiogenesis • echocardiography • gene therapy • microbubbles • myocardial infarction

Abbreviations and Acronyms   EF = ejection fraction   FAC = fractional area change   GFP = green fluorescent protein   LV = left ventricle   LVEAd = left ventricular end-diastolic area   LVEAs = left ventricular end-systolic area   LVEDV = left ventricular end-diastolic volume   LVESV = left ventricular end-systolic volume   MCE = myocardial contrast echocardiography   MI = myocardial infarction   PBS = phosphate-buffered saline   SCF = stem cell factor   SMA = smooth muscle actin   UTMD = ultrasound-targeted microbubble destruction   VEGF = vascular endothelial growth factor

Related Article

Ultrasound Mediated Destruction of DNA-Loaded Microbubbles for Enhancement of Cell-Based Therapies: New Promise Amidst a Confluence of Uncertainties?

Flordeliza S. Villanueva
J. Am. Coll. Cardiol. Img. 2009 2: 880-882. [Full Text] [PDF]

This article has been cited by other articles:

				F. S. Villanueva Ultrasound Mediated Destruction of DNA-Loaded Microbubbles for Enhancement of Cell-Based Therapies: New Promise Amidst a Confluence of Uncertainties? J. Am. Coll. Cardiol. Img., July 1, 2009; 2(7): 880 - 882. [Full Text] [PDF]