Novel metabolic labeling method for tracking stem cells to irradiated salivary glands using PET

The goal of this project was to develop and evaluate a novel metabolic labeling approach for long-term follow-up of stem cells in patient. Unlike existing approaches, metabolic labeling would not require genetic engineering of stem cells or labeling with long-lived thus harmful radioisotopes. This approach was thought feasible on the basis of tests performed using fluorescence microscopy, where fluorescent molecule were used to light up the stem cells of interest. Our goal was to extend these results by replacing the fluorescent molecule with a short-lived isotope that could be imaged in humans using PET scanners. Against our expectations, the proposed approach failed to label stem cells even under ideal laboratory conditions. We then proceeded to try a second and then a third approach based on the same concept, but without success. Putting all these results together, we now understand why the proposed approach failed and we have identified a fourth strategy that would solve the problem. We are close to find out whether this new approach will work, after which we shall be able to test it in vivo.