While conventional MRI detects the nuclear magnetic resonance signal from protons contained in the mobile water in tissue, 19F MRI detects the signal from the nucleus of the fluorine atom. Fluorine is not normally present in the body at sufficient concentrations to detect, so when Ahrens labels cells with PFPE, he can detect this fluorine 'tracer' with MRI after the cells are transplanted into the body. The Ahrens' team has recently used the PFPE technology to label and track dendritic cells and T cells in a mouse model of type I diabetes, a disease in which immune cells infiltrate the pancreas, attacking and damaging the body's own cells.
"Right now we're using our technology to image key cell types involved in autoimmune diseases like type I diabetes, but our cellular MRI agents also can be adapted to label other cell types, including cells from bone marrow and stem cells. A key long-term application of our technology is to label and monitor cell-based therapeutics in humans," Ahrens said.
Recent advances in cell-based therapeutics research have focused on training immune cells to counteract diseases including cancer and diabetes and on directing stem cells to regenerate damaged tissues. Non-invasively visualizing these therapeutic cells in patients after transfer can be a vexing problem, according to Ahrens, and any approach that can speed up the testing of these treatments will be extremely useful.
"Ideally we would label therapeutic cells with our cellular MRI agents before they are implanted into a patient. In this way, we could use MRI to visualize the m
|Contact: Jocelyn Duffy|
Carnegie Mellon University