Types Of Stem Cells

As you consider whether to bank your newborn baby’s stem cells, it is helpful to understand the various types of stem cells that exist, where they come from, and what they can do.

Hematopoietic Stem Cells

Hematopoietic stem cells (HSCs) can become any of the blood cells and cellular blood components in our body (such as white blood cells, red blood cells, and platelets), but not organs (such as lungs, interior stomach lining, nervous system tissue, and nerve cells from the brain). HSCs are found in cord blood from the umbilical cord and the placenta. HSCs are multipotent.

Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) can turn into a large number of tissue types such as bone, cartilage (the lining of joints), fat tissue, and connective tissue (tissue that is in between organs and structures in the body). They are sometimes called bone marrow stromal cells because in adults they are found mainly in the bone marrow. However, MSCs are also found in babies’ umbilical cord tissue and placenta tissue. MSCs are multipotent.

Multipotent Stem Cell

Multipotent stem cells can develop into any of the cells that make up the organ system that they originated from. They are found in adults as well as in the umbilical cord blood and umbilical cord tissue of newborn babies.

The two types of multipotent stem cells that can easily be collected immediately after the birth of a baby are called hematopoietc stem cells (HSCs) and mesenchymal stem cells (MSCs). HSCs are found in cord blood in the umbilical cord and the placenta and in the tissue of the umbilical cord and placenta. MSCs are found in umbilical cord tissue and placenta tissue.

Pluripotent Stem Cells

A pluripotent stem cell is one that has the potential to differentiate into any of the three germ (or body) layers: endoderm (interior stomach lining, gastrointestinal tract, the lungs), mesoderm (muscle, bone, blood, urogenital), or ectoderm (epidermal tissues and nervous system). Pluripotent stem cells can give rise to any fetal or adult cell type, including each of the more than 220 cell types in the adult body. Conversely, non-pluripotent stem cells can only produce a limited number of cell types. Cord blood found in the placenta is very rich in pluripotent stem cells.

Induced Pluripotent Stem Cells (iPS)

Induced pluripotent stem cells, commonly abbreviated as “iPS cells” or “iPSCs” are a type of pluripotent stem cell artificially derived from a non-pluripotent cell. They are similar to embryonic stem (ES) cells in many respects. iPSCs were first produced in 2006 from mouse cells and in 2007 from human cells. This has been cited as one of the most important advances in stem cell research, as it allows researchers to obtain pluripotent stem cells without the controversial use of embryos.

Embryonic Stem Cells

Embryonic stem cells are pluripotent stem cells derived from the inner cell mass of an early-stage embryo. Because isolating the inner cell mass results in the death of the fertilized human embryo, this raises ethical issues. Aside from the ethical concerns, there are also technical problems of graft-versus-host disease (a condition in which the recipient’s body rejects the stem cell transplant, possibly leading to death of the patient) associated with allogeneic stem cell transplantation. (An allogeneic transplant is one in which the stem cells from one person are used in another person; an autologous transplant is one in which a person’s own stem cells are transplanted in that same person.) Embryonic stem cell transplants also have a high incidence of causing tumors in patients. For these reasons, embryonic stem cells are not considered a viable therapy for patients.

Adult Stem Cells

Found in some of the body’s mature tissues, adult stem cells help our organs regenerate themselves (think of skin cells constantly replacing themselves). However, unlike pluripotent stem cells, adult stem cells can only give rise to more of the same type of cells from which they were derived. Aside from the non-pluripotent issue, there is a technical problem of graft-versus-host disease (a condition in which the recipient’s body rejects the stem cell transplant, possibly leading to death of the patient) associated with allogeneic stem cell transplantation. For these reasons, adult stem cells are not considered a viable therapy for patients.