Other Stem Cell Types
Umbilical cord stem cells
The umbilical cord blood does contain some stem cells that are genetically identical to the newborn. Similar to the adult stem cells, these are multipotent in nature and are able to differentiate into some, but not all, types of cells. Hence, umbilical cord blood is frequently banked, or stored, for potential future use should the individual require stem cell therapy.
Peripheral blood stem cells
Most of the blood stem cells are present in the bone marrow, but there are a few that are present in the bloodstream itself. These peripheral blood stem cells (PBSCs) can be isolated from a blood sample. The blood stem cells can differentiate to give a large number of varying types of cells that constitute the blood and the immune system, including RBCs, platelets, granulocytes, and lymphocytes.
Fetal stem cells
The embryo can be referred to as a fetus after the eighth week of gestation. The fetus contains stem cells that are pluripotent in nature and will eventually give rise to all of the different body tissues.
Placental stem cells
Placental stem cells are those stem cells that are found only in the placenta and are collected after the blood from the umbilical cord is drawn. They are non-embryonic stem cells, as are those obtained from umbilical cord blood. Additionally, besides banking cord blood stem cells, placental stem cells can also be collected and stored which will significantly increase the amount of preserved prenatal stem cells. It's advantageous as placental stem cells are a rich source of CD34+ stem cells.
Amniotic stem cells
Amniotic stem cells are multipotent in nature and are of mesenchymal origin. They are extracted from the amniotic fluid and they have the capability to differentiate into various tissue types, such as skin, nerves, muscle, cardiac tissue, cartilage, and bone, and have great potential medical applications, especially in organ regeneration. Amniotic fluid stem cells can be harvested without destroying embryos through amniocentesis although it does carry a small risk of pregnancy loss (estimated at 0.06%). Hence the use of amniotic fluid stem cells is generally considered to lack the ethical problems associated with embryos.