Magnetic Attraction of Stem Cells to Injured Heart Creates Potent Treatment

DotMedNews, April 12, 2010

The intracoronary administration of bone marrow stem cells in patients who have suffered a heart attack has been demonstrated to cause beneficial effects in double blind studies, as discussed in this video http://www.youtube.com/watch?v=flv0RmzPyLU. Intracoronary administration has potential side effects since a balloon needs to be expanded in the area where the heart attack occurred, which may cause exacerbation of the existing damage. A more attractive method of stem cell delivery would be via the intravenous route. Unfortunately, intravenous administration has the drawback that some of the cells become lodged in organs such as the lung and liver. Despite this, intravenous administration has demonstrated positive results, for example in a clinical trial conducted by Osiris (Hare et al. A randomized, double-blind, placebo-controlled, dose-escalation study of intravenous adult human mesenchymal stem cells (prochymal) after acute myocardial infarction. J Am Coll Cardiol. 2009 Dec 8;54(24):2277-86) an improvement in heart pumping ability was observed.

One way of improving stem cell homing to the area of need is through direct administration of proteins, or genes encoding the proteins, that specifically attract stem cells. This approach has been performed with SDF-1 in animal models, and now the company BioHeart is doing Phase I clinical trials. Other ways include the use of laser therapy to induce expression of stem cell homing molecules as being developed by the San Diego company Entest Biomedical.

Today a new approach was reported in the journal Circulation Research, which is published by the American Heart Association. Scientists at Cedars-Sinai Heart Institute have loaded stem cells with iron-nanoparticles and administered them intravenously in animals that were induced to undergo a heart attack by ligation of the coronary artery. The scientists found that by applying magnetic fields to the heart, they could increase the number of injected stem cells that lodged into the heart by 3-times. This was accompanied by functional improvement.

"Stem cell therapies show great promise as a treatment for heart injuries, but 24 hours after infusion, we found that less than 10 percent of the stem cells remain in the injured area. Once injected into a patient's artery, many stem cells are lost due to the combination of tissue blood flow, which can wash out stem cells, and cardiac contraction, which can squeeze out stem cells. We needed to find a way to guide more of the cells directly to the area of the heart that we want to heal." Said Eduardo Marban, M.D., director of the Cedars-Sinai Heart Institute.

Commenting on the success of the present study, he stated "This remarkably simple method could easily be coupled with current stem cell treatments to enhance their effectiveness."