Cell Therapy is the transplantation of live cells into a patient for therapeutic purposes. Stem cells are the ideal cells to be used for this purpose because of their two main properties: ability to replicate for long periods of time and to develop into different types of cells. There are 3 major types of stem cells: embryonic stem cells, adult stem cells, and induced pluripotent stem cells (iPSCs); the first two are naturally found, while iPSCs are produced in the laboratory.
Embryonic stem cells are undifferentiated cells obtained from a 5-day pre-implantation embryo. Embryonic stem cells are pluripotent, whereby they can give rise to ALL kinds of cells in the human body.
Induced Pluripotent Stem Cells (iPSCs) are genetically engineered adult cells, programmed to behave like pluripotent embryonic stem cells.
Adult stem cells, also known as somatic stem cells, are undifferentiated cells found in different areas of the body. They differ from embryonic stem cells as they are multipotent, whereby they can only develop into specific types of cells. Adult stem cells include the following:
- Hematopoietic stem cells are adult stem cells that develop into all types of blood cells and are found in the bone marrow.
- Mesenchymal stem cells can be found in the bone marrow and also other parts of the body. MSC’s can give rise to different cells including stromal cells, fat cells, bone cells, and cartilage cells.
- Neural stem cells differentiate into brain cells including nerve cells (neurons), astrocytes and oligodendrocytes.
- Skin stem cells give rise to different cells, depending on where they are found; those found at the base of the hair follicle differentiate into the epidermis or the hair follicle and those found in the basal layer of the epidermis result to keratinocytes.
- Epithelial stem cells result to absorptive cells, goblet cells, Paneth cells, and enteroendocrine cells and can be found in the lining of the digestive tract.