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| crochet umbilical cord by crochet artist Lauriane Lasselin |
I think the most misleading thing that hit me in the face after discussing cord blood banking with my husband, is that cord blood stem cells are basically the same as stem cells in your blood marrow. They are hematopoietic stem cells, not embryonic stem cells. I guess I was naive at first, because I assumed the reason for all the hype was because the stem cells were embryonic. Then it clicked...why would there be embryonic stem cells in the umbilical cord? There aren't, they are only in the embryo. So, the stem cells in the umbilical cord only give rise to different types of blood cells. The good thing about hematopoietic stem cells is that they self-renew, and transplanting a small number can repopulate the receiver's deficient blood cell population, after chemotherapy, for example. However, they have limited potential uses, and 80 diseases is definitely a stretch.
That leads to the next most misleading thing...they say that storing your child's cord blood can help if your child has leukemia. Unfortunately, this is just flat out wrong. The cord blood can help if your child is healthy and a sibling has leukemia. But leukemia is cancer of the bone marrow stem cells, which are the same as the cord blood stem cells. If your child has mutated, cancer-prone hematopoietic stem cells, it is likely genetic, so it stands to reason that you would not want to transfuse more mutated, cancer-prone cells from the umbilical cord into your child. But, if you find out your child has leukemia, a sibling's cord blood may have healthy hematopoietic stem cells that match, and could be useful. Even among siblings, the chance of a perfect match is low, with estimates ranging from 25-30%.
When compared with bone marrow transplants for leukemia, umbilical cord blood transplants are not consistently more successful. In general, mortality and occurrence of graft-vs-host disease were similar, and in one study, mortality and recurrence of leukemia were slightly higher with umbilical cord transplants. The main advantage that I discovered is that umbilical cord blood could have one or two mismatches in human leukocyte antigens (HLAs) and have a similar result as completely matched blood marrow. But, the biggest predictor of success in treating leukemia had nothing to do with the source of the transplant, it was how early in the disease progression it was treated.
A major drawback to umbilical cord blood transplants for leukemia is that there just isn't enough of it in the umbilical cord after birth. Adults typically can't use umbilical cord blood, unless they are able to obtain a double dose. Finding a double dose of matching cord blood is not easy, especially for African Americans. People from African ancestry have more diversity in HLA types, and even more new combinations of HLA types are present in people with both African and Caucasian ancestry, or various other combinations of ethnicities. In addition, African Americans make up a smaller portion of the population, and are less likely to donate bone marrow or cord blood. This leaves them without many options if they need any kind of transplant.
As many as two-thirds of cord blood samples that are donated are not usable because they are of insufficient quantity or quality, and are thrown out. You could imagine that the same would be true for privately banked cord blood. So, the way I see it, you could pay thousands of dollars only to find out that your banked cord blood is useless when you need it.
But, what about all those other diseases? Researchers are looking in to using cord blood to treat things such as cerebral palsy and autism. From what I can tell, nothing major has been accomplished as of yet, but people will always hold out hope. The more probable advances in cord blood therapy are technologies for multiplying hematopoietic stem cells so they can be used even if the sample is small, and the culture of mesenchymal stromal stem cells from the umbilical cord tissue. Mesenchymal stromal cells have the potential to be used for tissue regeneration and immunotherapy, but much work is yet to be done.
So, in the end, the private cord blood banks aren't wrong completely...there is a chance that by the time your child is grown up, advances in technology may very well open doors to very useful therapies using cord blood and tissue. In the same way, advances in technology will likely open doors to useful therapies using stem cells from other sources as well. It doesn't appear that the umbilical cord is some sort of holy grail. My advice? If you're going to privately bank, do your research to make sure it is a solid company that isn't going anywhere (I think the saying "you get what you pay for" applies here), and be sure they save the blood and the tissue of the umbilical cord. The more humanitarian and useful decision, however, is to donate your child's umbilical cord to a public bank. Sure, the chances of your child's cord blood being usable are small, but your child could very well save someone's life.
Sources and Further Reading:
Ballen, KK, et al. 2013. Umbilical cord transplantation: the first 25 years and beyond. Blood 122: 491-498.
Laughlin, MJ, et al. 2004. Outcomes after transplantation of cord blood or bone marrow from unrelated donors in adults with
leukemia. New England Journal of Medicine 351: 2265-2275.
Rocha, V, et al. 2001. Comparison of outcomes of unrelated bone marrow and umbilical cord blood transplants in children with acute leukemia. Blood 97: 2962-2971.
From the World Stem Cell Report 2009, published by the Genetics Policy Institute.
http://www.worldstemcellsummit.com/files/2009_report/4-8_2009.pdf
Great article on parents.com with more detail.
http://www.parents.com/pregnancy/my-baby/cord-blood-banking/the-cord-blood-controversy/
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