What are Pluripotent Stem Cells?

Pluripotent stem cells (PSCs) are undifferentiated cells that have two unique properties: they are capable of indefinite self-renewal and have the ability to differentiate into each of the three germ layers of the body.   

Pluripotent stem cells (PSC) is a term that encompasses both embryonic and induced pluripotent stem cells.  True” embryonic stem cells (ESCs) are derived from the inner cell mass (ICM) of a pre-implantation embryo.  Other types of cells defined as “embryonic” included parthenogenic pESCs created from unfertilized eggs, and ntESCs created by somatic cell nuclear transfer.  Induced pluripotent stem cells (iPSCs) are created through the process of reprogramming, which is directed de-differentiation of an adult somatic cell to pluripotency. 

Self-renewal is the capacity of the stem cells to divide to produce identical daughter cells that maintain the same properties of the original cell.  While other cell types have limited self-renewal capacity, pluripotent stem cells are able to self-renew indefinitely under appropriate culture conditions.  

Pluripotency is defined as the cells’ ability to differentiate into all three germ layers (ectoderm, mesoderm, and endoderm), therefore having the potential to develop into every cell type in the body.  Every PSC has the same potential to differentiate to any specialized cell type.  This property is of extreme interest to researchers in order to identify the specific conditions and chemical signals that direct a stem cell to exit from self-renewal and pursue a pathway to a specialized cell type.  While PSCs will spontaneously differentiate in culture, controlling the process to generate pure populations of functional somatic cells is the subject of many years of dedicated research.  

The promise of human pluripotent stem cells (hPSCs) for regenerative medicine lies their ability to serve as an unlimited source of starting material for both autologous and allogenic cell therapies.  Maintaining high-quality hPSCs in culture is dependent on consistent, defined culture conditions and proper handling techniques to achieve optimal cell expansion, differentiation, and purity for use in biomedical research and downstream therapeutic applications.