Placenta banking refers to the collection and storage of stem cells from the placenta

Placenta

The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and...

, in addition to those found in cord blood

Cord blood

Umbilical cord blood is blood that remains in the placenta and in the attached umbilical cord after childbirth. Cord blood is collected because it contains stem cells which can be used to treat hematopoietic and genetic disorders.-Collection:...

, after the birth

Birth

Birth is the act or process of bearing or bringing forth offspring. The offspring is brought forth from the mother. The time of human birth is defined as the time at which the fetus comes out of the mother's womb into the world...

 of a human baby. 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 cell

Embryonic stem cell

Embryonic stem cells are pluripotent stem cells derived from the inner cell mass of the blastocyst, an early-stage embryo. Human embryos reach the blastocyst stage 4–5 days post fertilization, at which time they consist of 50–150 cells...

s, as are those obtained from umbilical cord blood.

Both the placenta and umbilical cord

Umbilical cord

In placental mammals, the umbilical cord is the connecting cord from the developing embryo or fetus to the placenta...

 are also rich sources of stem cells. Banking stem cells from the placenta in addition to those found in cord blood significantly increases the number of prenatal stem cells that are collected and preserved.

Properties

The placenta is a rich source of CD34+

CD34

CD34 molecule is a cluster of differentiation molecule present on certain cells within the human body. It is a cell surface glycoprotein and functions as a cell-cell adhesion factor. It may also mediate the attachment of stem cells to bone marrow extracellular matrix or directly to stromal cells...

 stem cells. CD34+ cell dose is a factor that is consistently identified as significantly associated with rate of stem cell engraftment, treatment-related mortality, and survival.

Collection and storage

While cord blood is collected by a health care provider at the hospital, the placenta must be sent back to the laboratory for processing before the stem cells can be recovered. As such, placental stem cell collection and processing is more intensive than cord blood stem cell processing.

Both placental and cord blood stem cell units are processed and depleted of red blood cells and then cryopreserved in liquid nitrogen

Liquid nitrogen

Liquid nitrogen is nitrogen in a liquid state at a very low temperature. It is produced industrially by fractional distillation of liquid air. Liquid nitrogen is a colourless clear liquid with density of 0.807 g/mL at its boiling point and a dielectric constant of 1.4...

tanks at -196 degrees Celsius. Placental and cord blood stem cells units are stored in two separate cryopreservation bags, yielding two separate stem cell units. Recently, it has become evident that to preserve the greatest number of stem cells from the cord blood and placenta, cryopreserving the entire placenta in combination with cord blood banking is generally the best option since by cryopreserving the entire placenta, one may preserve up to 10 times more stem cells than other methods.

Usage

Cord blood stem cells have been used to treat over 80 diseases to date, including leukemia, Hodgkin's lymphoma, and sickle cell anemia. Over 8,000 cord blood stem cell transplants have been performed to date. Very few if any placental cell transplants have taken place, but this may become more common place in the future.

External links

• Americord Registry - placenta cryopreservation or PlacentaBanking as well as cord blood banking