Urine-Derived Stem Cells: A Novel Source for Tissue Engineering and Regenerative Medicine

Urine-derived stem cells (USCs) are present in fresh human urine, and can be easily isolated and expanded in vitro. They are capable of differentiating into different cell types, such as adipocytes, myocytes, chondrocytes, osteoblasts, neurocytes, epithelial cells, and endothelial cells, which enables them to be used as a stem cell-based therapy to modulate immune cells and treat previously incurable diseases. Preclinical studies have revealed that USCs can migrate to damaged locations, where they regulate the microenvironment and secrete paracrine factors to improve tissue recovery. In addition, their therapeutic applicability has been increased by genetic modifications designed to enhance differentiation and improve tissue targeting. Therefore, the potential use of USCs in tissue engineering and regeneration medicine is very promising. However, since the biological characteristics of USCs and their responses in vitro and in vivo are not fully understood, additional basic research and animal model-based studies are needed based before they can be applied to the clinic. Moreover, a number of problems are associated with USC-based therapies, including potential tumorigenicity, poor survival, low engraftment rates, and few reports of immunomodulatory functions. These problems all need to be solved in the near future.