What are the different kinds of stem cells?
Stem cells are essential for life and without them tissue such as bone marrow and skin would not be able to regenerate.
The regenerative properties of stem cells can potentially be harnessed to provide stem cell-based treatments for a wide range of diseases, often referred to as regenerative medicine.
There are stem cells associated with most tissue types but this review will focus on an overview of those stem cell types with current or potential clinical applications in the treatment of diseases and their properties.
There is some terminology which you need to understand in order to develop a good basic understanding of stem cell technology, these include:
Adult Stem Cells: These are stem cells which can be collected from tissue such as bone marrow and fat. Cord blood stem cells, even though they are collected from the blood remaining after the birth of a baby, are considered to be adult stem cells, as are cord tissue and placenta stem cells.
Embryonic Stem Cells: These are stem cells derived from early embryos at the blastocyst stage of development. In humans this is day 5 following fertilisation.
Induced Pluripotent Stem Cells (iPSC): These are created by the insertion of four specific genes into normal adult cells such as skin cells. The result is a stem cell which has the potential to create many tissue types.
Fetal Stem Cells: These are stem cells obtained from the developing fetus and they are collected following elective termination of pregnancy. They are considered to be adult stem cells.
Haemopoietic Stem Cells: They are 'blood forming' and are the stem cells found in the bone marrow and cord blood which give rise to all blood cell types.
Mesenchymal Stem Cells: These are multipotent stem cells capable of producing tissue such as cartilage, nerve, bone and fat. Mesenchymal stem cells are found in many tissues including umbilical cord and dental pulp.
CD antigens: These Cluster of Differentiation (CD) molecules are found on the surface of many cells and are used to characterise different cell types e.g. haemopoietic stem cells are CD34+.