Umbilical Cord Blood and Tissue Banking

By Cliff Librach, MD

Fall 2007

When a baby is born the umbilical cord is cut, and the baby enters the world physically separated from its mom. Within minutes, the structures which kept the baby attached to its mom, the placenta and umbilical cord, separate from the uterus and are delivered as the so-called ‘afterbirth’. These structures that were so vital for the pregnancy are no longer useful to the baby or mom, and become waste material. Millions of these are disposed of as waste each year although recent scientific advancements have shown how these structures can be put to use in the fight against disease.

 

In the 1980s, scientists began studying the blood that circulates within the umbilical cord and placenta. They were able to demonstrate that this blood, which is the baby’s, contains ‘stem cells’ that have the potential to form all of the various types of blood cells. These are called hematopoietic stem cells. In cord blood, they are found in far greater numbers than in adult bone marrow.

 

Stem cells are the building blocks of our body and have the capacity for self-renewal. They are subdivided into several types such as totipotent, pluripotent, unipotent and multipotent; however, for the purpose of this article, we will focus on multipotent stem cells. Multipotent stem cells can produce a family of closely related cells (e.g. the hematopoetic stem cells in bone marrow). Cord blood stem cells have been shown to not only make all types of blood cells, but can also change into cells of various other organs, such as the brain and lung, but not all cell types, and thus they are multipotent.

 

Once a baby is born and the cord is cut, the collection of cord blood is a very simple procedure (akin to taking blood for a blood test). While the placenta and cord are still attached to the mom, a needle is inserted into the umbilical cord vein and the blood is simply drained by gravity into a collection bag. There is absolutely no risk to the mother or child. The blood is then shipped to the cord blood bank where the stem cells are isolated from the blood using a multistep process that takes several hours. The number and purity of stem cells in the final preparation is then determined prior to packaging and freezing. These stem cells are a perfect match for the child from whom they were derived. However, it is important to note that for successful transplantation of these cells, a perfect match is not as crucial as it is for adult bone marrow transplants. Therefore, close relatives such as a sibling or parent, where there is some mismatching, can very often be an especially good candidate for successful transplantation. Another important consideration for those couples who used donor gametes to have a child is that one of the parent’s families would not be a source of possible transplantation, as they are not genetically related. Consequently, these ‘perfect match’ stem cells can give couples greater peace of mind for their child.

 

The first cord blood cell transplant was performed in 1988 on a 6-year-old boy with a condition called Fanconi’s anemia using a cord blood unit from a sibling. Since then, the field has exploded. There are now over 70 diseases that have been treated with cord blood cells. For an up to date list of these go to www.createcordbank.com/conditions.asp or www.parentsguidecordblood.org. Thousands of successful transplants have been performed worldwide and there are many more studies, either at the research or clinical trial stages, that are being conducted, some of which are listed in the links above.

 

Cord blood has a number of advantages over bone marrow as a source of cells for transplantation. Compared to marrow, cord blood transplants have less stringent matching requirements, a lower incidence of a rejection reaction, a lower risk of virus transmission to the recipient, and are more immediately available. Potential disadvantages are that cord blood stem cells provide a limited number of cells and therefore may not be sufficient for some larger patients. However, there have been many successful transplants in adults, and several groups are actively developing techniques to grow and increase the numbers of cells from their original numbers. This could enable transplants for all ages, and sizes of people. Having the ability to expand these cells in artificial culture systems will also help doctors deal with two other limitations of cord blood, i.e., length of time to engraftment and repeat transplantation from the same source.

 

A new type of stem cell derived from the cells surrounding the blood vessels (perivascular) of umbilical cord tissue has recently been discovered. These cells, called Peristem™ cells (www.peristem.com), have been shown to be multipotent. Peristem™ cells have the ability to form all of the structural cell types of our body (bone, cartilage, muscle, fibrous tissue and fat). Cells that can form these types of tissues are called mesenchymal stem cells (MSC). Currently, MSC’s that have been isolated from adult bone marrow are being used to enhance bone marrow, and other types of transplants. The process of obtaining bone marrow can be very painful, and isolation of MSC’s from marrow is a lengthy and laborious procedure. MSC’s have the incredible potential to treat such common diseases as arthritis, bone disorders, trauma to tissues (fractures, etc), burns and heart disease. In addition, MSC’s have been shown to work in concert with cord blood cells to speed up engraftment. Thus, they are considered complementary to cord blood cells to allow for treatment of many additional diseases. As of March 2007, Peristem™ MSC banking is available exclusively in Canada through the Create Cord Blood Bank (www.createcordbank.com).

 

There are two types of cord blood banks, public banks and family banks. Public banks are dependant on cord blood that is donated to them for processing. The family that donates the blood gives it up for others to use and no longer has access to it. These donated stem cells can then be used for recipients throughout the world through a cord blood stem cell network. There is only one government funded public bank that is operational in Canada, and it is located in Quebec (www.hemaquebec.ca). With a better understanding of the incredible value of cord blood and Peristem™ cells, there has been renewed interest in establishing more public cord blood bank facilities in Canada. However, public banks can only accept cord blood donations from designated local hospitals, and because of stringent banking criteria, only a small proportion of donated samples (<50%) are eventually available to public registries. The rest is either discarded or used for research. Only those families who deliver their babies at hospitals designated for a public bank have the option to do either public or family banking. Public banks are subsidized by government funds or donation. In contrast, family banking involves banking of stem cells for the exclusive use of that child or a family member. Family banking requires payment for initial processing, maternal blood testing and there is also an annual storage fee after the first year. Most family banks offer payment plans and waive the fee for a family that has a child with an immediate need for a transplant. For 99% of all births in Canada, the only options regarding their cord blood and cord tissue (Peristem™) stem cells are family bank storage or discarding them as waste.

 

Not all private banks are the same. Technological choices made by the bank may have long term effects on your baby’s precious stem cells. The most sophisticated system for cord blood banking is the Bioarchive® robotic system (www.thermogenesis.com or www.createcordbank.com). This system is a closed system as opposed to the conventional open systems that are in use in many of the older cord blood banks. In an open system, there is a risk of transient warming events (TWE) each time a rack of samples is lifted out of the tank to place a new one inside. This can happen hundreds of times during the process of filling the rack with samples and removing samples. In the closed Bioarchive® system, the samples are transferred into the tank with a robotic arm and no other samples are disturbed, thus avoiding TWE’s. For additional safety and security, the BioArchive® system utilizes multicompartment cryobags with a Teflon™ overwrap to ensure sample integrity and to eliminate the risk of sample cross-contamination. In conventional systems, there is a small risk of cross-contamination between vials or bags without an overwrap. To overcome this risk, these banks use vapour phase storage tanks. However these types of tanks are associated with an even higher risk of TWE’s. Samples in a cord bank can theoretically be stored in liquid nitrogen indefinitely. It has been estimated that, if kept stable and undisturbed, they would remain viable for hundreds of years!

 

Parents often ask: what are the odds that their baby’s cord blood or Peristem™ cells will be used for that child or a family member? The answer to this is complex, since so much research is going on in this field that the potential uses for cord blood are expanding rapidly. The public service website link http://parentsguidecordblood.org/content/usa/medical/medmotiv.shtml?navid=21 explores this question. However, with the tremendous research on such common conditions as heart disease, stroke, cancers, blindness, diabetes and arthritis (to name a few), there is so much potential for treating diseases where tissues are damaged from birth, by accident, from disease, or as a result of the degenerative effects of aging.

 

In summary, donation of cord blood for public banking has limited availability in Canada, but is an option for those parents delivering in participating hospitals. However, for most Canadian families, the choice is to either bank their newborn’s cord blood and/or Peristem™ cells, or discard them. Family banking of umbilical cord stem cells is a kind of ‘biologic insurance’ that is available to parents all across Canada. It is best to make the decision to bank your baby’s stem cells early in the pregnancy (preferably before 30 weeks), so you can receive the collection kit and be ready to go. Remember that if they are not collected at the time of birth, these potentially precious stem cells will be gone forever. 

 

Dr. Cliff Librach graduated from the University of Toronto and is a board certified Reproductive Endocrinologist and Infertility Specialist. He is the Director of the Sunnybrook & Women’s College Hospital Fertility Centre, Director and founder of the Create IVF Program. He is also the medical director of the Create Cord Blood Bank (www.createcordbank.com).