Stem cells or progenitor cells are found throughout the human body and act as an inherent repair system for various organ systems, replenishing adult tissues on a daily basis. These cells exist as undifferentiated or “non-specific, immature” cells and have the ability to self-renew via mitosis (i.e. increase in number via cell division thus expanding the innate stem cell pool) and also to differentiate into more specialized or “mature” cell types depending on their external environment. Due to these characteristics, the regenerative properties of stem cells have become an exceptional research and therapeutic tool and promises immense future therapeutic potential.
Types of Stem Cells
Stem cells can be classified into two major subtypes, those being embryonic and adult stem cells. Biologically, stem cells that are collected from fetal tissue such as the umbilical cord or umbilical cord blood are also classified as adult stem cells, and adult stem cells are therefore often referred to as tissue stem cells.