"Our results show that MRI tracking of mesenchymal stem cells can be used - as a replacement to surgical biopsy - to verify that such cell-based therapies reached damaged areas of the heart and were able to effect repair and improve heart function," says study senior co-investigator Jeff Bulte, Ph.D., an associate professor in radiology at Hopkins who developed the labeling method.

In other experiments in rabbits and dogs, the researchers successfully used the IRON method, which was developed at Hopkins, to track relatively small numbers of stem cells in the body and to deploy a metallic stent, a mesh-like device that opens blood vessels narrowed by fat and calcium buildup.

"Physicians must confirm that potential therapies, whether they are cell based or involve devices, are delivered as planned to the targeted organ or other part of the body," says lead investigator Wesley Gilson, Ph.D., a postdoctoral research fellow at Hopkins. Gilson's work was recognized at the heart meeting, where he was a finalist for the prestigious Melvin Judkins Young Clinical Investigator Award.

With IRON, conventional MRI technology is adapted to reveal images of ever smaller numbers of cells, avoiding image artifacts that mimic the appearance of iron-labeled cells.

Scientists were able to visualize metal objects, which previously appeared as dark spots on the MRI screen, by suppressing the vast majority of the conventional image produced from water molecules (or so-called on-resonant signal), the most common substance in the body.

By eliminating the water-based signals, the scientists were left only with the signal produced from metal objects (or so-called off-resonant signal), such as prosthetic screws, metal clips or stents.

In effect, Gilson says, the machine was made sensitive to iron molecules in the formerly unseen region. "We effect
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Contact: David March
dmarch1@jhmi.edu
410-955-1534
Johns Hopkins Medical Institutions
2-Dec-2005