Following magnetic targeting, there was a five-fold increase in cell localisation at a site of vascular injury in rats. The team also demonstrated a six-fold increase in cell capture in an in vitro flow system - where microscopic particles are suspended in a stream of fluid and examined to see how they behave.
Although magnetic fields have been used to guide cellular therapies, this is the first time cells have been targeted using a method directly applicable to clinical practice. The technique uses a United States Food and Drug Administration (FDA) approved agent that is already used to monitor cells in humans using magnetic resonance imaging (MRI).
Dr. Mark Lythgoe, UCL Centre for Advanced Biomedical Imaging, the senior author on the study, stated: "Because the material we used in this method is already FDA approved we could see this technology being applied in human clinical trials within 3-5 years. It's feasible that heart attacks and other vascular injuries could eventually be treated using regular injections of magnetised stem cells. The technology could be adapted to localise cells in other organs and provide a useful tool for the systemic injection of all manner of cell therapies. And it's not just limited to cells - by focusing tagged antibodies or viruses using this method, cancerous tumours could be much more specifically targeted."
Panagiotis Kyrtatos, also from the UCL Centre for Advanced Biomedical Imaging and lead researcher of the study, added: "This research tackles one of the most critical challenges in the biomedical sciences today: ensuring the effective delivery and retention of cellular therapies to specific targets within the body. Cell therapies could greatly benefit from nano-magnetic techniques which concentrate cells where they are needed most. The nano-magnets not only assist with the targeting, but with the aid of MRI also allow us to observe how the cells behave once they're injected."
This work was supported by public and charitable funding from the UCL Institute of Child Health - Child Health Research Appeal Trust, The British Heart Foundation, the Alexander S. Onassis Public Benefit Foundation and the Biotechnology and Biological Sciences Research Council (BBSRC).
The paper "Magnetic tagging increases delivery of circulating progenitors in vascular injury" is published on-line ahead of print in The Journal of the American College of Cardiology: Cardiovascular Interventions.
The UCL Centre for Advanced Biomedical Imaging is a new multi-disciplinary research centre for experimental imaging. The Centre is built around a number of groups at UCL and brings together imaging technologies across UCL with specific applications in the biomedical sciences. The researchers quoted are affiliated to UCL Medicine and UCL Institute of Child Health.
Founded in 1826, UCL was the first English university established after Oxford and Cambridge, the first to admit students regardless of race, class, religion or gender, and the first to provide systematic teaching of law, architecture and medicine. UCL is the seventh-ranked university in the 2008 THES-QS World University Rankings, and the third-ranked UK university in the 2008 league table of the top 500 world universities produced by the Shanghai Jiao Tong University. UCL alumni include Marie Stopes, Jonathan Dimbleby, Lord Woolf, Alexander Graham Bell, and members of the band Coldplay. UCL currently has over 12.000 undergraduate and 8000 postgraduate students. Its annual income is over GBP 600 million.