Identification, characterization and biological significance of very small embryonic-like stem cells (VSELs) in regenerative medicine.

The progress of stem cell research, along with technological innovation, has brought researchers to focus on the potential role of stem cells in regenerative medicine. Ethical and technological issues have limited the applications of human embryonic stem cells (hESCs) in this field. As a promising candidate, very small embryonic-like stem cells (VSELs) express a multitude of pluripotent stem cell markers and demonstrate the ability to differentiate into three germ-layer lineages in vitro. Optimized methods for isolation and expansion of VSELs have aroused the scientific community's interest in use of this kind of cells for regenerative purposes. In this review, we will focus on the biological characteristics, as well as the potentiality and remaining challenges in clinical application of VSELs. Moreover, a comparison among VSELs and the other pluripotent stem cells will be illustrated to highlight the unique advantages of VSELs.