CORD BLOOD: What is it & What can it Treat?
Cord blood is the blood that remains in the umbilical cord and placenta after a baby is born and the cord is cut, separating the baby from the mother. This blood is the baby’s blood.
The umbilical cord connects an unborn baby to the placenta. The umbilical cord pumps oxygen and nutrient rich blood from the placenta to the baby, and brings back the oxygen and nutrient depleted blood to the placenta once it has circulated through the baby’s body. It contains one vein, which brings the blood from the placenta to the baby, and two arteries, which bring the blood back from the baby to the placenta. The tissue surrounding these umbilical cord vessels is called “Wharton’s jelly”. The placenta, umbilical cord, and the blood in both are all genetically identical to the baby, not to the mother.
Umbilical cord blood is rich in Hematopoietic Stem Cells (HSCs), which are currently the most therapeutically valuable stem cells. HSC’s can replace bone marrow by differentiating into cells that can produce red blood cells, white blood cells, and platelets. These new cells produce the cellular ingredients necessary for the blood and the immune system and can rapidly create new blood for a patient. HSCs are currently being used to treat over 80 different blood, immune, and bone diseases 1.
In addition, new cord blood transplant treatments are being actively researched and implemented worldwide. Thus, it is becoming increasingly likely that cord blood banking will provide protection for your family.
Stem cells are simply “undifferentiated” cells, which have the potential to develop into other mature cells. All of the cells in our body are derived from stem cells.
Umbilical cord blood is a rich resource of hematopoietic stem cells. These stem cells are the “building block” cells of all of the blood components.
There are different kinds of stem cells, and they are found in different places and at different times in embryonic development.
Pluripotent or embryonic stem cells are found in one of the very first stages of embryonic development, the blastocyst stage, when an embryo is 4-5 days old. These cells have the potential to differentiate into all of the different cells in a baby’s body.
Embryonic stem cells are harvested from embryos created during an IVF cycle, but not transferred. They are widely used experimentally.
The hematopoietic stem cells found in the baby’s cord blood are different. They are not as primitive as the pluripotent stem cells since they have already started to become blood stem cells. They can, however, rapidly and efficiently create new blood for a patient. The stem cells found in cord blood have been used to regenerate new blood in patients who have blood diseases. The uses for hematopoietic stem cells, which are not considered controversial, have grown dramatically over the years. Cord blood is currently the standard of care for many blood diseases.
Cord tissue yields a third type of stem cells, called Mesenchymal Stem Cells (MSCs). Not to be confused with the stem cells derived from cord blood (Hematopoietic Stem Cells, or HSCs), MSCs are multipotent cells that differentiate into a variety of cell types including: osteoblasts (bone cells), chondrocytes (cartilage cells), myocytes (muscle cells), and adipocytes (fat cells), in an embryo. Clinical trials are currently underway to see if they can be made to develop in a way that is medically useful in the laboratory.
Until recently, it was assumed that hematopoietic stem cells, obtained from cord blood, could only be used as building blocks for blood cells. These stem cells were thought to be useful only in treating blood diseases. If you look closely at the list of current treatments for which hematopoietic stem cells are used, all of them are diseases of the blood.
Recently, cord blood research has discovered evidence that suggests that, under the right circumstances, cord blood may be conditioned to “change” into the building blocks of organ tissue. If that is truly the case, then the potential uses of cord blood stem cells will potentially be extraordinary, including treatment for everything from breast cancer to heart disease to diabetes.
If this potential is realized, then saving cord blood can contribute to your child’s health well into adulthood.
The hematopoietic stem cells found in the baby’s cord blood have already started to become blood stem cells and have been used to regenerate new blood in patients who have blood diseases. The uses for hematopoietic stem cells, which are not considered controversial, have grown dramatically over the years.
Pluripotent stem cells that are present in early embryos are the most basic stem cells. Since they are so primitive (or undifferentiated) they can actually create and form new tissue and new organs. This is what makes them so medically useful. Because they are harvested from embryos, usually leading to the destruction of the embryo, the future harvesting of stem cells is controversial.
The Stem Cell Controversy is Not Over Cord Blood Stem Cells
The stem cells found in the baby’s cord blood are fundamentally different. They are not taken from an embryo, but rather from an umbilical cord (which is generally discarded) after a baby’s birth. There is no controversy about collecting and storing cord blood stem cells because the cord blood would otherwise be medical waste.
There is no controversy about the ethics of cord blood banking.
What are the key milestones in the history of cord blood banking and cord blood stem cell transplantation?
- Dr. Hal Broxmeyer, of Indiana University (Indianapolis, IN), analyzed human cord blood for the presence of hematopoietic stem cells (HSC’s) and progenitor cells. He envisioned using these cells for transplant to reconstitute the human hematopoietic system.
- Dr. A.D. Auerbach, of the Rockefeller University (New York, NY), showed that prenatal diagnosis could be used to rule out Fanconi anemia in the unborn sibling of a child with Fanconi anemia, setting the stage for the first cord blood stem cell transplant.13 The fetus would have a 75% chance of not having the disease, and if so, once born the infant’s cord blood could potentially be transplanted to the affected sibling.
- The first related cord blood stem cell transplant was performed in 1988 in Paris, France, in a procedure led by Professor Eliane Gluckman. The patient was a child with Fanconi anemia and the donor was an HLA-identical sibling shown by prenatal testing not to have the disease. (Since the genes for Fanconi anemia and HLA type are on different chromosomes, this is quite possible.) The transplant was successful, without Graft vs Host Disease (GvHD), and the patient was alive and free of disease more than 15 years after the transplant. The donor stem cells fully reconstituted the patient’s hematologic and immune system.14,13
- Transplantation of umbilical cord blood from an HLA-identical sibling to treat a child with chronic myelogenous leukemia (CML) was reported.15 The recipient had first been treated with myeloablative therapy to destroy existing HSCs. (Basically, all of the cells in the sick sibling’s bone marrow were intentionally destroyed with .) The donor stem cells successfully engrafted in the recipient’s bone marrow and were documented in the circulating blood. This case showed that umbilical cord blood contains sufficient numbers of HSCs to treat children with leukemia following myeloablative therapy. Unfortunately, in this patient the CML recurred.
- The first HLA-partially matched cord blood transplant (not a complete match of all six tested HLA antigens; see Glossary for definition of HLA system) to treat a child with acute lymphoblastic leukemia.
- An umbilical cord blood transplant in an adult with chronic myelogenous leukemia (CML) was reported. 16 A 26-year-old patient received a cord blood transplant from an unrelated donor after myeloablative therapy. The cord blood was obtained from a public blood bank. The donor-recipient pair were a 5/6 HLA match. The donor’s stem cells successfully engrafted and the recipient’s peripheral blood was completely replaced by donor-derived blood cells. Eight months after the transplant, the patient had no evidence of CML.
- Unrelated umbilical cord blood transplants in children were reported.17 Twenty-five children with various malignant and non-malignant diseases received cord blood transplants from unrelated donors. One donor-recipient pair was a perfect (6/6) match, 20 had one mismatch (5/6), three mismatched at two HLA sites (4/6), and one pair mismatched at three sites (3/6). Twelve of the 25 children (48%) survived and did not have a disease-related event for The study demonstrated that partially mismatched (at 1 to 3 HLA sites) cord blood transplants from unrelated donors were a possible, though imperfect, source of stem cells which could sometimes reconstitute the hematopoietic system.
- Report of successful umbilical cord blood stem cell transplant in a child with sickle cell anemia was published. 18 The patient received cord blood cells collected from a sibling who was an identical HLA match, and was a carrier of the sickle cell trait, but did not have the disease. Complete donor cell engraftment was reported, with no graft-vs-host-disease. The recipient was cured of sickle cell anemia.
- A published study shows less risk of both acute and chronic graft-versus-host disease with umbilical cord blood transplants from HLA-identical siblings compared to bone marrow transplants from HLA-identical siblings, establishing the superiority of cord blood HSCs to peripheral blood HSCs. 19
- Fifteen years of basic science and clinical research, and accumulated experience with individual cases of cord blood stem cell transplantation, demonstrates successes and promise of using cord blood to treat a variety of hematologic, immunologic, genetic, and malignant diseases.
- An estimated 30,000 cord blood stem cell transplants have been performed to date, targeting at least 80 different disorders.
- Within the past decade, researchers have begun to examine the effectiveness of using cord blood transplantation to treat a broader range of disorders including, for example, type I diabetes, cerebral palsy, autism, sickle cell disease, Alzheimer’s disease, multiple sclerosis, and metabolic disorders.
- Since the mid-2000s, clinicians have been optimizing approaches that use two of cord blood for adult transplants. Scientists have also been developing methods to multiply the number of stem cells in a single unit of cord blood, prior to transplantation, to allow for expanded dosing and transplants in larger individuals.
Yes, it is possible to do both. Cord blood can be collected regardless of when the cord is clamped.