What are stem cells?
Stem cells are often called master cells, and form the foundation for your entire body as building blocks for the blood, immune system and organ tissue. They have the ability to replicate and regenerate themselves. It’s these two characteristics that give them the potential of differentiating into any kind of cell in the body.
Types of stem cells
There are different kinds of stem cells that can be found in the human body throughout the course of life. They vary in exactly what they can and cannot do, but fall within three main categories.
Adult stem cells can be found throughout our bodies, such as bone marrow, fatty tissue and peripheral blood, where they work as a repair system in maintaining the specific tissues they are found in. They are also referred to as tissue-specific or somatic cells.
Cord blood and tissue stem cells can be found in a newborn baby’s umbilical cord and placenta. These stem cells are practically brand new, so they have an advantage over adult stem cells in their potential to transform into any cell in the body with the ability to continuously renew themselves. Collecting these cells uses a non-invasive and painless procedure that carries with it no moral, ethical or religious concerns – the umbilical cord and placenta are usually discarded as medical waste after birth.
Embryonic stem cells are controversial. They are used in research but there is ongoing ethical debate about how they are obtained.
Cord blood stem cells
The blood that is found in the umbilical cord and placenta after a baby’s birth is rich in haematopoetic stem cells (HSCs). HSCs are blood-forming stem cells that can differentiate into red blood cells, white blood cells and platelets.
This is what makes them so useful, as blood stem cell transplantation can potentially be used to treat bone marrow failure, blood cancer and other blood disorders. It’s the fact that HSCs can be used as an alternative to bone marrow or peripheral blood stem cells in transplantations that sets them apart.
Cord tissue stem cells
The stem cells that are found in the tissue that surrounds the umbilical cord, as well the umbilical vein and arteries (called Wharton’s Jelly), are called mesenchymal stem cells (MSCs). They have the potential to repair or even create tissues like skin, cartilage, muscle, bone, nerve cells or organs. This is what makes them important in regenerative medicine – which is considered experimental at this time and so should only be used in ethically approved clinical trials. There are trials looking into the use of MSCs in the potential to treat Alzheimer’s, liver and heart failure, bone regeneration, HIV, Type 1 diabetes, and more.
Endothelial progenitor cells (EPCs) are found in the tissue of the umbilical cord, as well as its vein and arteries. These cells basically make up the circulatory system, from the heart to the tiniest blood vessel. EPCs are considered to be extraordinarily special since they play a vital role in regeneration of blood vessels. Researchers have demonstrated that they play a significant role in regeneration and the reconstruction of tissue of the heart, brain and skin.
There are yet another kind of stem cell that can also be found in the lining of the umbilical cord. These are known as epithelial stem cells (EpSCs). They have the potential to be used in soft tissue repair, such as skin wounds, ocular surface disorders, even haemophilia (as per clinical trials that have taken place).
While these cells can be obtained from other sources in the body, such as bone marrow, the benefits of using those cells obtained from the umbilical cord tissue makes them the future of cell therapy and regenerative medicine.
The advantages of banking
your baby’s cord cells
Collecting stem cells from a newborn baby is quick, painless and easy – there is no risk associated with collecting cord cells. Once a baby is born, the umbilical cord is clamped and cut as per normal in any birth. It is only after this that the blood and tissue are collected from the umbilical cord and placenta for stem cell processing, so cord blood and tissue collection poses no medical risk to the newborn baby or mother. Moreover, because the stem cells are collected from organs that are usually discarded as medical waste after the birth of a baby, the process is entirely free of ethical or moral concerns.
A newborn’s stem cells are young and flexible, which means they have better regenerative abilities. Umbilical cord stem cells have greater therapeutic potential than adult stem cells. They are young and active in comparison with stem cells from other sources – a maximum of nine months old – which means that they can differentiate faster. There is a growing body of evidence showing that umbilical cord-derived mesenchymal stem cells are more robust than MSCs from other sources. Cord tissue MSCs also have anti-inflammatory properties, a capacity to modulate immunity and the ability to stimulate regeneration.
Cord blood is collected in advance, tested and stored frozen – ready to use when needed. Because your baby’s stem cells were collected at birth, they are ready to use if necessary. Unlike bone marrow, there is no need to take time to locate a possible donor and then determine whether he or she is still willing and able to donate.
Cord blood and tissue can be stored successfully for more than 20 years – until your child reaches early adulthood if you wish.
Stem cells derived from the umbilical cord blood and tissue are a 100% match for your baby. Should your child require medical treatment using stem cells in the future, they will be matched for his body. If a sibling needs stem cells therapies, these stored cells have a 25% chance of a perfect match, and a 50% chance that a sibling will be a partial tissue match.
Cord blood transplants do not require a perfect match in the case of unrelated transplants. Studies have shown that cord blood transplants can be performed in cases where the donor and the recipient are only partially matched. In contrast, bone marrow grafts require 10/10 matching in most cases. Because partially matched cord blood transplants can be performed, cord blood increases a patient’s chance to find a suitable donor. Since HUCT (human umbilical cord tissue) mesenchymal stem cells are immune system privileged, cell rejection is not an issue and HLA matching is not necessary.
Cord blood transplants are associated with lower incidence of graft versus host disease (GvHD). The immune cells in cord blood seem to be less likely to attack the recipient’s own tissues than those in bone marrow from unrelated donors.
Cord blood transplants are associated with lower risk of viral contamination. Cord blood is also less likely to transmit certain common viruses, such as Epstein-Barr virus (EBV) and cytomegalovirus (CMV). These are potentially lethal infections for transplant recipients. CMV is carried as a latent virus by about 70% of the SA population, whereas less than 1% of babies are born with CMV.
Bone marrow stem cells
vs.
Umbilical cord stem cells
Umbilical cord stem cells are collected from the umbilical cord and placenta after a baby is born – and after the cord has been clamped and cut – so it does not harm baby or mother in any way, carries no medical risk, and is completely non-invasive.
Bone marrow is a spongy tissue found inside larger bones (like the hip) that produces blood-forming stem cells for your body. In order to access and collect these cells, a surgical procedure is performed where doctors insert needles into the pelvic bone to draw out the marrow.
The bone marrow releases a small number of blood-forming cells into the blood, where they are called peripheral (circulating) blood stem cells (PBSCs). In order to collect these for transplant, a donor is given injections of a medication that moves more of the blood-forming cells from the bone marrow into the blood. The cells are collected from the blood, in a similar way to a platelet blood donation.
The blood found in the umbilical cord and placenta is a rich source of blood-forming stem cells. Cord blood contains nearly 10 times the amount of blood-forming cells that are found in bone marrow.
Once it has been collected, processed and stored, the stem cells from your baby’s umbilical cord and placenta are readily available. There is no need to first search for a matched donor, and no need for invasive procedures to collect these cells.
Because the stem cells found in the umbilical cord and placenta are a maximum of nine months old, they are younger and more flexible than those found in bone marrow. Studies suggest that cord blood may also have a better ability to generate blood cells than bone marrow.
Furthermore, studies have shown that that cord blood transplants can be performed in cases where the donor and the recipient are only partially matched. Bone marrow transplants, however, can only be done with a perfect match.
Likewise, there is less risk of a transplant recipient developing graft vs host disease, as well as a lower risk of viral contamination when using stem cells derived from the umbilical cord and placenta.
South Africans can’t rely
on bone marrow stem cells
Bone marrow transplants require 10/10 HLA match, but with just 75 000 donors currently enrolled through the South African Bone Marrow Registry the search for a donor is difficult. Patients requiring a blood stem cell transplant will have a probability of 25% for a sibling match, and if no match is found the patients will be dependent on local and international registries to find a match. However, it is important to note that South Africa does not currently have a public stem cells bank.
Should a child from mixed descent be diagnosed with a blood cancer or disorder, the search for a possible stem cell match can be debilitating to a family’s finances and hope for recovery. In addition, delays in commencing stem cell therapy, and the high costs involved, could hamper the success of the treatment. Having direct access to stem cells harvested from the cord blood and tissue of your children can prove life-saving.
The cost associated with cord blood and tissue banking is also significantly lower compared to that of a bone marrow or peripheral blood stem cell collection, and the chances of finding a donor match are also greatly increased, as your child’s own stem cells provide a perfect match.
