Umbilical cord blood is blood that remains in the placenta and in the attached umbilical cord after childbirth. Cord blood is collected because it contains stem cells, which can be used to treat hematopoietic and genetic disorders.
Cord blood is used the same way that hematopoietic stem cell transplantation is used to reconstitute bone marrow following radiation treatment for various blood cancers, and for various forms of anemia. Its efficacy is similar as well.
Adverse effects are similar to hematopoietic stem cell transplantation, namely graft-versus-host disease and the risk of severe infection while the immune system is reconstituted. There may be a higher risk of infection with cord blood compared with traditional HSCT, as cord blood is slower in generating immune cells.
Collection and storage
Umbilical cord blood is the blood left over in the placenta and in the umbilical cord after the birth of the baby. The cord blood is composed of all the elements found in whole blood. It contains red blood cells, white blood cells, plasma, platelets and is also rich in hematopoietic stem cells. There are several methods for collecting cord blood. The method most commonly used in clinical practice is the "closed technique", which is similar to standard blood collection techniques. With this method, the technician cannulates the vein of the severed umbilical cord using a needle that is connected to a blood bag, and cord blood flows through the needle into the bag. On average, the closed technique enables collection of about 75 ml of cord blood.
Collected cord blood is cryopreserved and then stored in a cord blood bank for future transplantation. Cord blood collection is typically depleted of red blood cells before cryopreservation to ensure high rates of stem cell recovery.
The first successful cord blood transplant (CBT) was done in 1988 in a child with Fanconi anemia. Early efforts to use CBT in adults led to mortality rates of about 50%, due somewhat to the procedure being done in very sick people, but perhaps also due to slow development of immune cells from the transplant. By 2013 30,000 CBT procedures had been performed and banks held about 600,000 units of cord blood.
Society and culture
In the United States, the Food and Drug Administration regulates any facility that stores cord blood; cord blood intended for use in the person from whom it came is not regulated, but cord blood for use in others is regulated as a drug and as a biologic. Several states also have regulations for cord blood banks.
In Europe, Canada, and Australia use of cord blood is regulated as well. In the United Kingdom the NHS Cord Blood Bank was set up in 1996 to collect, process, store and supply cord blood; it is a public cord blood bank and part of the NHS.
Private and public banks
A cord blood bank may be private (i.e. the blood is stored for and the costs paid by donor families) or public (i.e. stored and made available for use by unrelated donors). While public cord blood banking is widely supported, private cord banking is controversial in both the medical and parenting community. Although umbilical cord blood is well-recognized to be useful for treating hematopoietic and genetic disorders, some controversy surrounds the collection and storage of umbilical cord blood by private banks for the baby's use. Only a small percentage of babies (estimated at between 1 in 1,000 to 1 in 200,000) ever use the umbilical cord blood that is stored. The American Academy of Pediatrics 2007 Policy Statement on Cord Blood Banking stated: "Physicians should be aware of the unsubstantiated claims of private cord blood banks made to future parents that promise to insure infants or family members against serious illnesses in the future by use of the stem cells contained in cord blood." and "private storage of cord blood as 'biological insurance' is unwise" unless there is a family member with a current or potential need to undergo a stem cell transplantation. The American Academy of Pediatrics also notes that the odds of using one's own cord blood is 1 in 200,000 while the Institute of Medicine says that only 14 such procedures have ever been performed. Private storage of one's own cord blood is unlawful in Italy and France, and it is also discouraged in some other European countries. The American Medical Association states "Private banking should be considered in the unusual circumstance when there exists a family predisposition to a condition in which umbilical cord stem cells are therapeutically indicated. However, because of its cost, limited likelihood of use, and inaccessibility to others, private banking should not be recommended to low-risk families." The American Society for Blood and Marrow Transplantation and the American Congress of Obstetricians and Gynecologists also encourage public cord banking and discourage private cord blood banking. Nearly all cord blood transfusions come from public banks, rather than private banks, partly because most treatable conditions can't use one's own cord blood. The World Marrow Donor Association and European Group on Ethics in Science and New Technologies states "The possibility of using one’s own cord blood stem cells for regenerative medicine is currently purely hypothetical....It is therefore highly hypothetical that cord blood cells kept for autologous use will be of any value in the future" and "the legitimacy of commercial cord blood banks for autologous use should be questioned as they sell a service which has presently no real use regarding therapeutic options."
The American Academy of Pediatrics supports efforts to provide information about the potential benefits and limitations of cord blood banking and transplantation, so that parents can make an informed decision. In addition, the American College of Obstetricians and Gynecologists recommends that if a patient requests information on umbilical cord blood banking, balanced information should be given. Cord blood education is also supported by legislators at the federal and state levels. In 2005, the National Academy of Sciences published an Institute of Medicine (IoM) report titled "Establishing a National Cord Blood Stem Cell Bank Program".
In March 2004, the European Union Group on Ethics (EGE) has issued Opinion No.19 titled Ethical Aspects of Umbilical Cord Blood Banking. The EGE concluded that "[t]he legitimacy of commercial cord blood banks for autologous use should be questioned as they sell a service, which has presently, no real use regarding therapeutic options. Thus they promise more than they can deliver. The activities of such banks raise serious ethical criticisms."
Though uses of cord blood beyond blood and immunological disorders is speculative, some research has been done in other areas. Any such potential beyond blood and immunological uses is limited by the fact that cord cells are hematopoietic stem cells (which can differentiate only into blood cells), and not pluripotent stem cells (such as embryonic stem cells, which can differentiate into any type of tissue). Cord blood has been studed as a treatment for diabetes. However, apart from blood disorders, the use of cord blood for other diseases is not a routine clinical modality and remains a major challenge for the stem cell community.
Along with cord blood, Wharton's jelly and the cord lining have been explored as sources for mesenchymal stem cells (MSC), and as of 2015 had been studied in vitro, in animal models, and in early stage clinical trials for cardiovascular diseases, as well as neurological deficits, liver diseases, immune system diseases, diabetes, lung injury, kidney injury, and leukemia.
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