The focus of Dr. Hess’ research is to understand the mechanisms by which distinct stem cell subsets co-ordinate hematopoiesis, angiogenesis, and tissue repair. Ultimately, Dr. Hess is interested in the development of cellular therapies to mediate the repair of diseased, damaged, or ischemic tissues. Specific applications for his work include the use of transplanted human stem cells to promote wound healing and blood vessel formation, and to regenerate insulin-producing beta cells during diabetes.

In an attempt to isolate and study the regenerative functions of human bone marrow-derived stem cells, Dr. Hess' lab has purified multiple (hematopoitic, endothelial, and mesenchymal) stem cell lineages simultaneously using high-speed fluorescence activated cell sorting based on a conserved stem cell function (high aldehyde dehydrogenase activity) and cell surface markers. These progenitor cell lineages can be expanded efficiently in vitroand their regenerative functions are studied by the transplantation in immune deficient mouse models specifically designed to track the contributions of human cells during blood vessel formation during critical limb ischemia, and during the regeneration of islet function in hyperglycemic recipients