The experts weigh in on how important of a medical resource cord blood can be.
Your baby’s umbilical cord contains tissue and a small amount of blood. They are both rich sources of powerful stem cells that could come in handy down the road. So don’t be so quick to discard them, as they may just end up being a lifesaver.
Dr Tang Kin Fai, laboratory director at Cordlife Group Limited, emphasises that the probability of needing stem cells is higher than previously thought, with as many as 1 in 217 people estimated to require a stem cell transplantation in their lifetime.
What is cord blood?
Cord blood is the blood that circulates between the foetus and the placenta, through the umbilical cord. It is a rich source of haematopoietic (blood-forming) stem cells (HSCs). HSCs have the unique ability to differentiate into different types of cells, namely red blood cells, white blood cells, and platelets, which transport oxygen throughout the body, produce antibodies and fight infections, and assist in blood clotting respectively.
Human leukocyte antigen (HLA) typing is what determines whether a bone marrow or cord blood transplant is viable. Our immune system uses these HLA markers to recognise which cells belong in our body and which do not. There are six HLA types that are crucial for stem cell transplants. Compared to a bone marrow transplant which requires a match of all six, a cord blood transplant requires only a four out of six match.
According to Valerie Wong, CEO of StemCord Pte Ltd, there are certain groups of individuals who will find it difficult to come across a match through traditional bone marrow registries or public cord blood banks. These include those from mixed marriages, minority races, and families with a history of cancer, and difficult pregnancies. These individuals stand to benefit the most from cord blood banking.
How banking works
Before being discarded, the umbilical cord is clamped and cut for the cord blood to be collected from the umbilicus vein. The collection process is completely non-invasive, painless, and safe for both mother and baby.
Some cord blood banks simply cut the umbilical cord into smaller pieces before freezing and storing them. At Stemcord, the cord stem cells are extracted before storage. This increases the cell yield by eight times, compared to that of frozen tissue.
After collection and processing, the cord blood is
cryogenically preserved (in liquid nitrogen tanks at
a temperature of -180°C). Two to three million cells
will then be cultured prior to freezing and stored
until they are requested for clinical use.
The Superiority of Cord Blood
Autologous and allogeneic transplants
Autologous stem cell transplants refer to transplants where the donor and recipient of the stem cells are the same individual. In such cases, there will be a 100 per cent HLA match. Your baby’s cord blood can also be used for allogeneic transplants, which involve a person receiving HSCs from a genetically similar but not identical donor, who is often an immediate relative, but could be an individual who is completely unrelated.
As Singapore’s only public cord blood bank, the Singapore Cord Blood Bank (SCBB) has successfully found stem cell matches for over 229 people locally and internationally, over the course of the last 12 years. Carol Teo, manager of corporate development at SCBB says, “In order to find a suitable match for unrelated allogeneic transplants, there must be a 4/6 HLA match, a minimum cell dose of 25 million cells per kilogram of the recipient’s body weight, and no infectious diseases, genetic disorders, or microbial contaminations.”
Treatment for a host of diseases
Umbilical cord stem cells (UCSCs) are younger than bone marrow stem cells (BMSCs), and so are in a more primitive state. This means that UCSCs have a greater ability to differentiate into a wider variety of cell types, like nerve cells, bone cells, and muscle cells, which are crucial for fully repairing injuries or restoring function to damaged tissues.
Cord blood stem cells can potentially be used to treat
many diseases, including blood disorders, immunodeficiency
syndromes, and acute and chronic forms of leukaemia.
In a cord blood transplant, stem cells are infused into a patient’s bloodstream where they work to heal and repair damaged cells and tissue. The HSCs in cord blood are able to replenish blood and regenerate the immune system.
Lesser risk of complications
Graft-versus-host disease (GvHD) is one of the most common and life-threatening side effects of a stem cell or bone marrow transplant. Wong explains, “GvHD occurs when the transplanted stem cells recognise the recipient's body as foreign and act to reject it.” With cord blood stem cell transplants, there is a lesser risk of complications because the criteria for HLA matching is not stringent.
“Because of the lower risk of GvHD, cord blood transplants can be attempted even if there is no perfect HLA matching. So, besides being useful for the child, the cryopreserved cord blood may also provide a lifeline to other family members,” she says.
Moreover, cord blood stem cells are easier to harvest and do not entail any risk to either mother or child. On the other hand, harvesting blood stem cells from bone marrow requires the use of general anaesthesia, and the process involves some pain. Teo describes, “In order to extract the stem cells from the bone marrow, the donor has to receive injections over a period of time to allow the stem cells to move out of the bone marrow to their bloodstream.”
The Future is Now
Clinical trials using cord blood stem cells are currently looking to reveal ways they may play a role in regenerative medicine. Dr Tang mentions, “Current areas of active research and ongoing clinical trials include cerebral palsy, autism, and brain injury. To date, most of these therapies require the patient’s own stem cells, and not those from a donor. Once these advances translate into successful treatments, families that have stored their child’s cord blood stem cells will have more medical options at their disposal.”
With the continuous advancement of stem cell research, the potential for the future use of stem cells will only continue to expand.