The role of non-invasive imaging and cell labelling techniques in the clinical assessment of stem cell therapy

Introduction Non-invasive imaging can play several potential roles in cardiac regenerative therapy. In preclinical models, postmortem evaluation, both grossly and microscopically, can be performed to determine therapeutic efficacy. However, in cardiac clinical trials of stem cell therapy, obtaining cardiac tissue for sampling, such as from biopsy, is rarely performed due to the invasive nature. Thus, many preclinical studies have employed traditional imaging techniques to measure cardiac morphology, function, perfusion, and flow by echocardiography, radionuclide imaging, and/or cardiovascular magnetic resonance imaging (MRI) to optimize stem cell therapy protocols. These imaging studies provide surrogate measures of morbidity and mortality for measuring the success of cellular therapies in clinical trials. Recently, cellular labeling methods have been extended to the many types of stem cells in animal models of cardiovascular disease that open new avenues for cell targeting and tracking in combination with these non-invasive imaging techniques. It can be envisioned that cellular labeling techniques will be extended to cardiovascular stem cell clinical trials in the near future to enhance the interpretation of both negative and positive outcomes and ultimately for the tailoring of stem cell therapies to individual patients.