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What is Cord Blood ?
Cord blood or umbilical cord blood
is the human blood from the placenta and umbilical cord that is
rich in hematopoeitic stem cells. Thus cord blood serves as a
source of stem cells from the new born. Cord blood is the blood
that remains in the umbilical cord after a baby is born. It is a
unique substance, which, like bone marrow, is rich in stem
cells. Stem cells are the building blocks of the blood and
immune system and potentially the nervous system; skin and bone
tissue; and the heart, pancreas and other central body tissues.
In essence cord blood is the blood found inside the umbilical
cord, the flexible cordlike structure connecting fetus at the
abdomen with the placenta from the mother to provide the
transfer of nutrients and removal of waste from the unborn baby.
Following the birth of a baby, the umbilical cord is cut and
usually discarded, along with the placenta. However, medical
research has shown that the blood that is retrieved from the
umbilical cord is a rich source of stem cells which are
genetically distinctive to the baby and its family. Stem cells
are unspecialized cells that can develop into specialized cells
such as muscle cells, red blood cell, or a brain cell. These
stem cells function as dominant cells because they contribute to
the development of all tissues, organs and systems in the body.
Stem cells possess the ability to transform into other types of
cells in the body and create new growth and development, they
are the building block of the immune system. Stem cells from the
baby’s cord blood is a valuable medical and biological resource
that may be required to address certain diseases or conditions
of a parent or sibling. Cord blood is retrieved from the
umbilical cord after it has been cut preventing any possible
pain, discomfort or harm. Stems cells are what make cord blood
valuable. Stem cells are important for living organisms for many
reasons. Like donated bone marrow, stem cells from umbilical
cord blood can be used to treat various genetic disorders that
affect the blood and immune system, leukemia and certain
cancers.
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Uses of
cord blood
Like donated bone marrow, stem cells from umbilical cord blood
can be used to treat various genetic disorders that affect blood
and immune system, leukemia and certain cancers. Therefore
parents can choose to save their babies’ cord blood in case of
future need. Private cord blood banks recruit expectant mothers
to donate their babies’ umbilical cord blood, and thus they
ensure that the cord stem cells are available to the family who
have preserved the cord blood. The stem cells are an exact match
for the baby, and the cells have at least a one in four chance
of being an exact match for a sibling. Fathers have a 25% chance
of matching their child's cord blood stem cells. Siblings have a
25% chance of being a perfect cord blood match.The cord blood
banks collect, process, test and store the donated umbilical
cord blood.
Cord blood provides a readily available source of stem cells for
transplantation in many situations where bone marrow is
considered. The following is a list of diseases that have
included cord blood stem cell treatment:
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Cancers
• Acute lymphoblastic leukemia
• Acute myelogenous leukemia
• Burkitt’s lymphoma
• Chronic myelogenous leukemia
• Juvenile chronic myelogenous leukemia
• Chronic lymphocytic leukemia
• Liposarcoma
• Myelodysplastic syndrome
• Chronic myelomonocytic leukemia
• Refractory anemia with excess blasts in transformation
• Neuroblastoma
• Non-Hodgkin’s lymphoma
• Refractory Hodgkin’s disease
• Retinoblastoma
Bone marrow failure syndromes
• Severe aplastic anemia
• Blackfan-Diamond anemia
• Dyskeratosis congenital
• Fanconi anemia
• Myelofibrosis
Hemoglobinopathies/Blood disorders
• Amegakaryocytic thrombocytopenia
• Evans syndrome
• Kostmann’s syndrome
• Sickle cell anemia
• Cooley’s anemia
Inborn errors of metabolism
• Adrenoleukodystrophy
• Bare lymphocyte syndrome
• Batten disease
• Familial erythrophagocytic/Hemophagocytic lymphohistiocytosis
• Gunther disease
• Hunter syndrome
• Hurler syndrome
• Krabbe disease
• Langerhans cell histiocytosis
• Lesch Nyhan disease
• Osteopetrosis
• Tay Sachs disease
Immuno deficiencies
• Chronic granulomatous disease
• Common variable immune deficiency
• Omenn’s syndrome
• Severe combined immune deficiency
• Reticular dysgenesis
In addition, cord blood stem cell is being done or potential
future use in the treatment of:
• Stroke
• Immune disorders such as multiple sclerosis, erythromatus
lupus
• Heart disease
• Muscular dystrophy
• Neurological disorders(eg ALS)
• Muscular/ Cartilage diseases.
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Collection of cord blood
The collection process is done after the baby is born, takes 2-4
minutes and is easy, painless and non-invasive. Collecting cord
blood poses no health risk to the mother or the infant donor.
The cord blood is stored only with the mother's signed consent,
and no collection is made if there are any complications during
delivery. After the baby's birth, the umbilical cord is clamped,
breaking the link between the baby and the placenta. Trained
members of staff drain the blood from the umbilical cord and
placenta. The blood is usually collected using a needle to draw
the blood into a blood bag. The collection usually takes ten
minutes or less and it is then sent off for cord blood storage.
On average, about three to five fluid ounces are collected from
the umbilical cord to produce enough stem cells.
There are 2
main methods in cord blood collection from umbilical vein |
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• Ex utero method: In this method
cord blood is collected after the placenta is delivered and the
umbilical cord is clamped off from the newborn. The placenta is
placed in a sterile supporting structure with the umbilical cord
hanging through the support. The cord blood is collected by gravity
drainage yielding between 40-150 mL
• In utero method: A similar collection
method is done except that the cord blood is collected after the
baby has been delivered but before the delivery of the placenta. A
syringe is used to draw blood from the umbilical cord shortly after
the umbilical cord has been cut.
After collection the cord blood units must be immediately shipped to
a cord blood bank facility. At public cord blood banks, this blood
is then analyzed for infectious agents and the tissue-type is
determined. Cord blood is processed and depleted of red blood cells
before being stored in liquid nitrogen for later use. When
cryopreserved cord blood is needed, it is thawed, washed of the
cryoprotectant, and injected through a vein of the patient. This
kind of treatment, where the stem cells are collected from another
donor, is called allogeneic treatment. When the cells are collected
from the same patient on whom they will be used, it is called
autologous and when collected from identical individuals, it is
referred to as syngeneic.Cord blood collection does not interfere
with delivery and is possible with vaginal or cesarean deliveries.
Studies have shown good cord blood cell recovery after upto 10 years
of storage.
Advantages of cord blood
In addition to cord blood, other sources of stem cells include bone
marrow and peripheral blood. Increasingly, experts say cord blood
transplants have distinct advantages over more traditional bone
marrow transplants in stimulating the growth of healthy white blood
cells. Cord blood has therapeutic advantages over adult stem cells,
some of which are as follows:
• Cord blood is also a richer source of stem cells than bone marrow,
with nearly 10 times as many blood-producing cells, so fewer cord
blood cells are needed for a successful transplantation.
• Cord blood has therapeutic advantages over adult stem cells. Cord
blood stem cells, unlike adult stem cells, are less likely to
contain DNA abnormalities caused by sunlight, toxins and errors in
DNA replication during the course of a lifetime.
• Collection of cord blood is simple and painless whereas bone
marrow donors must undergo general anesthesia.
• It is thought that because cord blood stem cells are younger, they
have better proliferative properties-that is, they are able to
regenerate more than bone marrow stem cells.
• If the cells are needed for transplant, it's been shown that the
transplant recipient is more tolerant of a partial match if the
cells are from a related donor. Additionally, transplant recipients
of cord blood stem cells are less likely to develop severe
complications from Graft-versus-Host-Disease than those receiving
bone marrow transplants. Graft vs. host disease is a serious,
life-threatening immune response to blood transplants. It can be
fatal for up to 40% of patients who get GVHD. Because cord blood is
more primitive , the T-cells found in cord blood that make up the
recipient’s new immune system are less likely to attack the
recipient’s body. This means a lower incidence of GVHD for cord
blood transplants. Because the stem cells in cord blood are younger,
matching between donor and recipient does not have to be perfect.
This means that you can treat a broader range of recipients with
cord blood. It also means that a recipient is less likely to get
GVHD.
Although cord blood cells have distinct advantages over traditional
bone marrow transplants, there are few drawbacks of cord blood stem
cells. It has been found that cord blood stem cells also engraft
more slowly than stem cells derived from bone marrow or peripheral
blood. Until engraftment occurs, patients are at risk of developing
life-threatening infections. Also, the number of stem cells present
in cord blood is significantly less than what’s routinely used in
bone marrow or peripheral blood stem cell transplants. However, this
is overcome by manipulating cord blood in the laboratory to expand
the number of stem cells present in the sample.
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