New way to track stem cell migration could advance treatments for brain tumours


A new study in the September issue of Stem CellsTranslational Medicineshows how a team of scientists led by Rex Moats, and Karen Aboody, have discovered a safe and effective way to track the migration and distribution of neural stem cells used in the treatment of invasive brain tumours. 

The researchers’ method, which involves “pre-loading” the cells before transplantation with ultra-small, superparamagnetic iron oxide nanoparticles that can then be detected via magnetic resonance imaging (MRI), has been approved for clinical trials in humans and has the potential to greatly accelerate the search for new treatments for deadly brain tumours and other diseases.

Numerous stem cell-based therapies are currently under investigation, including an FDA-approved clinical trial focused on employing neural stem cells (NSCs) in delivering drugs targeting invasive brain tumors.  “The ability to monitor the time course, migration and distribution of stem cells following transplantation into these patients would provide critical information for optimising treatment regimens,” Moats, Department of Radiology, Children’s Hospital of Los Angeles, and University of Southern California’s Keck School of Medicine, USA, said. “However, no effective cell-tracking methodology had yet garnered clinical acceptance.”

A labelling and imaging protocol using clinical grade ferumoxytol — an iron replacement product currently approved to treat iron deficiency anaemia in patients with chronic kidney disease — has shown promise in some studies as a possible tracking agent. The Moats-Aboody team, in conjunction with Joseph A Frank, a co-investigator at National Institutes of Health, had previously demonstrated that the combination of ferumoxides with protamine sulphate showed promise in labelling the NSCs for this purpose.

In this most recent study, they wanted to build upon their work by testing how adding heparin to the ferumoxytol and protamine sulphate mix might affect the NSC labelling.

The results were extremely promising in the lab. “Additionally,” Aboody, Department of Neurosciences, City of Hope National Medical Center and Beckman Research Institute, Duarte, USA, said, “when we tested it on mice with brain tumours we were able to track the NSC distribution using an MRI at multiple time-points following intracerebral or intravenous injection. The mice demonstrated no significant clinical or behavioural changes, no neuronal or systemic toxicities and no abnormal accumulation of iron in the liver or spleen.”

“Overall, we propose that ferumoxytol-labeling is an effective cell-tracking method that is safe for clinical use, contributing little to the risk side of a given risk/benefit analysis,” Moats concluded.