Innovative imaging aids stem cell research

One of the major areas of importance for the transition of cell-based therapies to clinical use is the ability to monitor transplanted cells over a long period of time and in a noninvasive manner. Biomedical engineering professor Simon Cherry is leading the way in that regard, with his effort to create high resolution, in vivo imaging techniques and tools that can monitor cells after transplantation.

The UC Davis College of Engineering professor not only takes an innovative approach to imaging technology, he is also at the forefront of creating the machinery for it.

"All the imaging technologies that are so important in diagnostic medicine - magnetic resonance imaging, positron emission tomography and computed tomography - could also be invaluable to further basic medical research," said Cherry. "But fundamental changes are needed to adapt them for that purpose."

Taking sophisticated images of small, living animals, often needed for basic research, is a challenge. Instruments must have better resolution because of the animals' size, as well as better sensitivity to detect the tiny amounts of contrast agents required to avoid disturbing the underlying physiology.

Cherry is particularly interested in PET (positron emission tomography) and optical imaging, which provide a snapshot of a body's activity rather than its anatomy. Using fluorescent or radioactive tags, researchers can target specific chemical pathways. With this technique, researchers can tag transplanted stem cells and track potential differentiation.

The field of molecular imaging is seeking to take advantage of the extraordinary amount of information generated from the sequencing of the human genome, including the roles of specific genes and proteins in health and disease. Combinatorial chemistry and high-throughput screening techniques also serve as important catalysts in finding molecules that can target specific proteins and can lead to new ways to image biologic targets in vivo.

In addition, by breaking down the traditional academic research walls and establishing interdisciplinary programs, scientists like Cherry, can work with computer scientists, chemists, biologists physicians and others throughout the UC Davis campus to ensure that imaging science, biology and translation into clinical applications are seamlessly and successfully integrated.

Imaging research and innovation is a key element in UC Davis' new Center for Pediatric Stem and Progenitor Cell Translational Research, which received a $6 million grant from the National Institutes of Health in October 2005. Being able to assess the safety and efficiency of cell-based therapies in humans requires imaging tools with sufficient sensitivity to detect small quantities of cells. This type of monitoring will crucial for the success of any regenerative medicine breakthroughs or therapies.