Objective: 

Strategies using cellular cardiomyoplasty or cardiac gene therapy aim at improving cardiac function in the diseased heart. However, one major problem is transduction and/or positioning of cells at selective sites.

Methods: 

We have addressed this by using magnetic nanoparticles (MNPs) in combination with custom made magnets in order to position bone marrow cells (BMCs) or embryonic cardiomyocytes (eCMs) to specific sites in vitro and in vivo. For this purpose magnetic fields for the localized attraction of MNPs were calculated and the appropriate magnets designed.

Results: 

Our experiments revealed site specific positioning of MNP loaded cells (BMCs and eCMs) in cell culture.Furthermore, our in vivo experiments showed a prominent (7–8 fold) increase of the rate of cell engraftment when applying a local magnetic field during and for 10 minutes after the intramyocardial injection of cells. We also assessed the site-specific positioning of MNP/lentivirus (LV) complexes in the murine heartex vivoin the Langendorff-perfusion system. After repetitive coronary perfusion an intramyocardial accumulation of MNP/LV complexes were seen within the area of magnet placement.

Conclusion: 

The combination of MNPs with specifically designed magnets enables the site specific and efficient transduction of cells within the cardiovascular system. In addition, MNP-loading of cells in combination with magnetic field application strongly improves engraftment rates. Both of these approaches are potentially interesting for therapeutic purposes in the cardiovascular system.