14 DAY TRIAL // Experts at the Stanford University School of Medicine announce the development of a new technique for tracking stem cells in the human body, particularly those used for medical applications, such as treating arthritic joints and other conditions.
The method relies on the use of iron particles that are administered to patients intravenously. The element labels the stem cells with a marker that can be observed via Magnetic Resonance Imaging (MRI). The new study was focused on bone marrow-derived mesenchymal stem cells (MSC).
These cells can be used for a variety of applications, including tissue repair and other forms of stem cell-based therapy. Until now, researchers had no way of tracking how these cells spread through the human body once they were injected, meaning that their efficiency could not be accurately measured.
The work was led by Heike E. Daldrup-Link, MD, PhD, who is an associate professor with the Department of Radiology at Stanford. He also holds an appointment as a member of the Molecular Imaging Program at the university. Daldrup-Link coauthored a paper detailing the new tracking method, published in the October issue of the journal Radiology.
“The most common problem is that stem cells, when transplanted, die and disappear from the transplant site. Alternatively, they stay in the correct site but don’t differentiate into cartilage,” the expert says. The iron/MRI approach could help reveal instances when such things happen in practice.
By using this method, doctors will be able to determine how much connective tissue, bone and cartilage MSC create at the sites where they are injected. Patients' progress could be tracked every day, week or month, according to needs, and the original MSC injections supplemented as needed.
“Our solution was to give an iron supplement to the stem cell donor intravenously before harvesting. The donor cells, including bone marrow stem cells, pick up the iron oxides, and these stem cells can then be tracked with [MRI],” Dr. Daldrup-Link explains.
The team found that MSC were capable of taking up a lot more iron if the element was injected directly into the blood stream than when the cells are taken out of the body, and grown in an iron oxide solution in the lab. An additional benefit is that labeling the stem cells inside the body eliminates the risk of contamination.
“Orthopedic surgeons want labeled stem cells, but not the ones that are manipulated between the bone marrow harvest and transplantation,” Dr. Daldrup-Link concludes. His investigation was supported by the Radiological Society of North America (RSNA).