Stem cells often surface in articles that describe the latest ideas that could change the way diseases are treated, including everything from cancer to dementia. Here at eurostemcell.org we aim to give you the information to help you understand and make decisions about these ideas.
What would you say if you were told that a substantial proportion of an easily accessible source of stem cells is being thrown away daily? This is the case with umbilical cord blood stem cells, but should families being paying for theirs to be stored? Rebecca Wagner takes a look at the pros and cons of cord blood banking.
What are umbilical cord stem cells?
Umbilical cord stem cells are found in cord blood and they are a type of blood stem cell. These cells are able to reconstitute all the different cell types found in normal blood. Blood stem cells are normally found within bones in children and adults and are responsible for maintaining a functioning blood system. A healthy blood system contains several different cell types that fulfil different jobs for keeping us alive, such as carrying oxygen and protecting us against viruses and bacteria. This makes umbilical cord stem cells potentially valuable for treating certain diseases.
Uses of umbilical cord stem cells
Blood cancers have been treated with stem cells for decades. The patient is conventionally treated with either radiation therapy, chemotherapy or a combination of the two. These treatments kill the cancerous cells in a non-specific way, meaning a lot of normal blood cells are also destroyed. Stem cell transplantation can replace blood cells damaged by either the disease or the treatment.
Blood stem cells can be obtained from several sources. Firstly, stem cells can be harvested from the patient prior to treatment (autologous transplant). The stem cells are then re-introduced back to the patient after treatment. However, this type of transplantation carries the risk that the cancerous cells may be transferred back to the patient. Alternatively stem cells may be donated by a family member or unrelated individual (allogenic transplant). This is often preferred as the risk of contaminating cancer cells is far lower. Only a minority of patients find a relative that is a suitable match for transplantation, and unrelated individuals may be located anywhere in the world, which can pose logistical problems when trying to obtain stem cells.
Umbilical cord stem cells represent an exciting source of cells for allogenic transplantation. They can be predictably and safely obtained after the birth of a baby and stored until needed. However, an important limitation to be aware of is that an adult requires the stem cells of two umbilical cords.
Besides cancer there are a number of other blood disorders where the use of umbilical cord stem cells has been approved as a treatment option. This includes immunodeficiencies and genetic diseases such as sickle cell disease. Cord blood has proven extremely useful in circumstances where a healthy blood system needs to be reconstituted.
How are umbilical cord stem cells collected?
Cord blood is collected from the placenta and umbilical cord after the birth of a baby. This is a non-invasive procedure that has minimal risk for both mother and baby.
Cord blood collection. Figure created with BioRender.
It is currently not common practice to collect cord blood. This is partly due to the costs associated with long term storage and partly due to ethical difficulties. To be most effective, umbilical cord stem cells should be collected from as many births as possible, but can donations be enforced?
How can umbilical cord stem cells be stored?
The UK has a national cord blood bank which contains more than 22,000 cord blood units with approximately 16,000 suitable for transplant and the remainder for research. Many other countries also have nationwide umbilical cord blood banks. These registries collect and store cord blood stem cells and match donations with recipients in need of a stem cell transplant.
Private companies have also been established that will bank cord blood for paying customers. However, several bodies have said that they do not support private companies. This includes the Royal College of Midwives, the Royal College of Obstetricians and Gynaecologists and the American Academy of Pediatrics.
Disadvantages of private umbilical cord blood banking
Besides the cost of private cord blood banking, there are also some other disadvantages to consider. Firstly, if a person has blood cancer, they are not usually given their own stem cells, due to the risk that the mutation that causes the disease is already in the cord blood. Although this risk is reduced in cord blood, a risk remains. Furthermore, an older child or adult would require stem cells from two umbilical cords, so privately storing blood from a single umbilical cord is insufficient for a successful treatment - a donation of blood from a second immuno-matched cord would need to be found.
Public banking also guarantees standardised processing and storage, which is essential for ensuring that the material is clinically useful – this is not always the case with private banks. Therefore, if a private bank is the appropriate choice for your circumstances, ensure that they have proper accreditation from the human tissue authority (HTA).
Currently the only realistic situation where private cord blood banking is beneficial is if the donor has a relative that is in need and is also a full match.
Concluding remarks
The world is entering an era in which it is rediscovering the importance of sustainability. The use of umbilical cord stem cells fits neatly into this ethos, as although the umbilical cord is essential for sustaining a growing foetus, the umbilical cord is discarded after birth, and yet it can be very valuable, for a limited set of circumstances.
Some private companies are currently advertising unrealistic possibilities about what is possible with stored blood from a single cord. Furthermore, it has been shown that the chances of the cord blood being used successfully are much higher if cord blood is donated to a public bank. Ensuring the decision about banking privately or publicly is an informed one is of utmost importance.
