Stem cells are the body’s raw materials — cells from which all other cells with specialized functions are generated. Under the right conditions in the body or a laboratory, stem cells divide to form more cells called daughter cells.
These daughter cells become either new stem cells or specialized cells (differentiation) with a more specific function, such as blood cells, brain cells, heart muscle cells or bone cells. No other cell in the body has the natural ability to generate new cell types.
Sources of Stem Cells
Adult Stem Cells, Human Umbilical Cord Tissue Mesenchymal Stem Cells (HUCT-MSC), Bone Marrow Stem Cells, Fat Stem Cells.
Stem cells can come from different sources, including:
Embryonic stem cells: These are derived from the inner cell mass of a developing embryo, typically at the blastocyst stage (approximately five days after fertilization).
Fetal stem cells: These are derived from fetal tissue, typically obtained during prenatal testing or through donations from terminated pregnancies.
Umbilical cord stem cells: These are obtained from the umbilical cord blood or tissue after a baby is born.
Adult stem cells: These are undifferentiated cells that are found in various tissues and organs throughout the body, such as bone marrow, adipose tissue, and the nervous system.
Induced pluripotent stem cells (iPSCs): These are adult cells that have been reprogrammed to behave like embryonic stem cells through genetic or chemical manipulation.
Synthetic stem cells: These are artificial stem cells that are created in the laboratory through the use of biomaterials, such as hydrogels, that mimic the properties of natural stem cell niches.
The source of stem cells can affect their properties and potential uses in research and therapy. Embryonic stem cells and iPSCs, for example, have the ability to differentiate into any cell type in the body and are being studied for their potential use in regenerative medicine and disease modeling. Adult stem cells, on the other hand, have more limited differentiation potential, but can still be useful in tissue repair and regeneration.
MSCs are self-renewing, multipotent precursors to other cell types and tissues. Scientists have found MSCs in many tissues from young to old. As we age, we appear to have fewer MSCs with the older MSCs typically behaving differently from the younger MSCs. MSCs have exciting potential and have shown great promise, whether we use our own aged MSCs or a graft from postnatal sources.
MSCs have demonstrated indirect local effects (similar to paracrine activity) that appears to be active for many weeks – possibly longer. It is thought that they may be responding to their local environment and, like healthy refreshed soldiers, may be able to effect change and regeneration in a customized way the host cells may no longer be fully capable of.
Postnatal tissues have high concentrations of MSCs across multiple compartments/tissues and these MSCs exhibit a more robust secretome and more rapid cell division frequency yet with a lower rate of teratogenesis.
Also known as embryonic stem cells, totipotent cells can become extraembryonic (placental cells/tissue). “Totipotent” means that these cells can differentiate into any type of cell or tissue which would indicate vast potential. However, because of the risks of teratoma, this type of stem cell is unsuitable for therapeutics and using it is illegal in the United States.
Pluripotent stem cells can differentiate into any of the cell types in a body. Pluripotent cells give rise to the endoderm, mesoderm, and ectoderm.
These cells give rise to many types of cells but are more limited than pluripotent cells. Multipotent stem cells are found in postnatal umbilical cord and placenta tissues, as well as in adult tissues. They serve as a reservoir of cells for growth and repair. Each type of multipotent stem cell gives rise to a limited range of cell types. These cells are more difficult to isolate for clinical use but are ethical. Examples of multipotent stem cells include hematopoietic stem cells (HSC) and mesenchymal stem cells (MSC).