Endothelial Progenitor Cells and Nitric Oxide: Matching Partners in Biomedicine

Regeneration of damaged tissue by embryonic or adult stem cells has been and still is a topic of highest interest in experimental and clinical medicine. Adult stem cells have the ability to differentiate into a number of different cell types in dependence on their environment. Endothelial progenitor cells (EPCs) represent a population of adult stem cells. They contribute to the renewal of the largest organ of the body: the endothelium which is the inner layer of the vessel wall.

After an introduction into the topic of EPCs presenting the origin, fate, and biology of EPCs, we describe techniques of cell culture and bioassays for in vitro and in vivo testing of EPCs. Their applications in animal models and in humans are described to demonstrate the relevance of EPCs in cardiovascular medicine. On the other hand, nitric oxide (NO), a key player in cardiovascular biology, is introduced and the first findings describing the apparently powerful interactions between EPCs and NO are discussed. EPCs and NO seem to be the “Yin and Yang” of endothelial function and regeneration. We would like to illustrate recent findings of EPC biology with a special interest in their interaction with NO. Finally, we open the wide and interesting spectrum of further research activities in this field of biomedicine. If the differentiation of EPCs could be controlled in the laboratory, these cells may become the basis of cell-based therapies for cardiovascular disease. An interdisciplinary approach and the cooperation between scientists, engineers, and physicians will be able to transfer the findings of basic science into daily clinical application. Initial ideas and first steps for the realization of new concepts in EPC–NO research and therapeutic strategies with a special reference to bioengineering concepts are discussed.