CONTEXT: Neural stem cells (NSCs), transplanted into the brains of mice with a condition similar to multiple sclerosis have proved effective in repairing damage caused by the disease within a day of injection. Although previous studies have shown the effectiveness of NSCs for similar treatment, this research demonstrated that the therapeutic potential of NSCs could be preserved after magnetic labeling (infusing the cells with iron particles). Dr. Letterio Polliti, a clinical neuroradiology assistant at Ospedale San Raffaele, and Dr. Giuseppe Scotti, chair of neuroradiology at the University and Scientific Institute San Raffaele, both in Milan, Italy, monitored stem cells in vivo and noninvasively with MRI.
RESULTS: Polliti and Scotti injected NSCs labeled with a superparamagnetic iron oxide contrast agent into the brains of healthy mice to confirm that labeled cells could be detected by in vivo MRI. Six mice were injected with MOG35-55 (myelin/oligodendrocyte glycoprotein) to develop experimental autoimmune encephalomyelitis (EAE, an animal model of MS). Nineteen days after immunization, the researchers transplanted labeled NSCs into the mice and acquired T2-weighted spin-echo and gradient-echo sequences over the course of 30 days. One day after transplantation, they detected magnetically labeled cells inside the demyelinating lesions. NSCs increased the number of glial cells, which produce myelin, and the symptoms in the mice improved.
IMAGE: Brain MR image of an EAE mouse reveals phases of the disease and treatment: in the acute phase of EAE (top), with a demyelinating lesion in the olfactory bulb (middle), and after intravenous injection of labeled stems that appear as a darkened area in the circle (bottom).
IMPLICATIONS: "Cell therapies are becoming a promising treatment for heretofore untreatable CNS disorders, including multiple sclerosis," Polliti said in a news conference at the 2004 RSNA meeting. "The development of an MRI-based method to track labeled cells in vivo thus represents an important tool to follow transplanted cells noninvasively and a crucial step toward the application of this therapy in humans."