INTRODUCTION:
Stem cells are unspecialized cells that can be
differentiated into any type of cell in the body.
Umbilical cord blood stem cells are haemotopoetic cells that are derived from
the blood of umbilical cord and placenta after birth. They are identified as
stem cells because they express CD34 molecule.(1)
Umbilcal cord blood was considered to be a waste
product of the birthing process but now it is known to have up to 10 times more
stem cells than adult bone marrow (2)
Research on stem cell transplants began in
the 1950s, with successful bone marrow transplants occurring in the 1970s,
often to treat cancer patients whose own bone marrow was destroyed by
chemotherapy and radiation.
The first successful umbilical cord blood stem cell
transplant was reported as occurring in the late 1980s. (3) There are several
advantages of umbilical cord blood. First Advantage is that umbilical cord
blood is easier to collect and process than bone marrow. Second advantage is that after it is saved and and
sent to a storage facility, the cord blood is quickly available for use within
days to weeks after processing. Third advantage is that it is less costly than
bone marrow collection. Fourth advantage is that there is less transmission of
infections and less rejection. (4) Cord blood banking involves collecting blood
left in the newborn's umbilical cord and placenta and storing it for future
medical use. Collection of the cord blood is is painless and is safe for the
baby and the mother.(5)
DISCUSSION:
Human umbilical cord contains in vitro stem cells
which were found before they were detected in the bone marrow of a human. The
frequency of stem cells in both human bone marrow and human umbilical cord is
the same but the numbers differ. Umbilical cord blood from a single donor
serves as a source of autologous haemotopoetic repopulating cells. These cells
are cryopreserved. The cord blood should not be separated or washed in order to remove the cell types prior to
freezing since all such procedures causes reduction in the number of
haemotopoetic progenitor cells. Cord blood infused into the donors immediately
after thawing would not lead to serious problems.Siblings of the same biological parents have a
25% chance of being a perfect match and 50% chance of being a parietal match.
(6)
The first umbilical cord blood stem cell transplant
was reported in the 1980s. The recipient was a 6 year old boy from North
Carolina who was suffering from Fanconi's anaemia. He was treated using the
cord blood which was obtained from his younger sister's birth. Surprisingly
even after 20 years after the transplantation, this young man is still alive.
Not only did he survive long term, but both his immune system and his blood
were transformed by the transplant of his sister’s cord blood stem cells. Soon
after this first documented cord blood stem cell transplant, the first public
umbilical cord blood bank was established in 1991 in New York.
Four main categories of physical conditions which can be treated with the help of stem cell transplants
are :
1) Cancer eg: Acute Biphenotypic Leukemia, Acute
Lymphocytic Leukemia (ALL)..
2) Blood disorders eg : Acute Myelofibrosis, Fanconi's
anaemia.
3) Congenital metabolic disorders eg: Gaucher's disease, Krabbe's disease.
4) Immunodeficiencies eg : Adenosine Deaminase
Deficiency (SCID), Evans disease.
Researchers continue to find new applications of stem
cells in the use of treating patients with lupus, multiple sclerosis, heart
attacks and systemic sclerosis.
"Regenerative uses for
stem cells are purely in the research stage and, so far, no tangible evidence
supports any clinical uses beyond the diseases that are currently being
treated." (2, 3, 4)
Umbilical cord blood is a
rich source of mesenchymal stem cells (MSC's). MSCs are present in the sub
endothelial lining of the umbilical cord vein and can be isolated using many
routine technical approaches. MSCs have the capability to differentiate into
many mesenchymal tissues. In the middle of gestation UCB is enriched with
pluripotent MSCs. Despite the fact that bone marrow has a high content of MSCs,
it may become unacceptable due to its high degree of viral
infection and the decreased proliferative activity which
becomes
less with age. (7)
Buerger's disease which is
also called thromboangiitisobliteran
is a rare, nonatherosclerotic, inflammatory and a vasocclusive disease
characterised by a combination of thrombosis and inflammation of arteries and
veins in the hand and feet. There is no cure or surgery for this disease and
hence stem cell therapy using umbilical cord blood has been derived by
researchers to cure this disease. UCB derived MSCs are chosen because
1)it can directly reconstitute arterioles
2) produce a large amount of cytokines and growth
factors
3) are capable to differentiate into endothelial cells
Based on their large ex vivo expansion and their
potential to differentiation, UCB derived MSCs provide an alternative and an
attractive source for gene transfer therapy for curing the vasocclusive
diseases like Alzheimer's disease, Parkinson's disease and so on. Recently it
has been reported that UCB-derived MSCs could show functional and morphological
improvement in a female patient with chronic spinal cord injury. (8)
From September 1994, umbilical cord blood from sibling
donor has been used in 44 children to reconstitute haemapoesis with acquired
lympho- haematopoetic disorders, neuronal stomp and metabolic disorder. (9)
Krabbes disease is an autosomal recessive disorder due
to the deficiency of the lysosomal enzyme galactocerebrosidase which is
characterised by failure of myelination in CNS And PNS leading to neurological
deterioration and death.
In infants, this disease appears before 6 months of
age and includes dysphagia, mental retardation, blindness, deafness etc.
Allogenic haematopoetic stem cells transplantation has been reported to be
beneficial in patients with juvenile Krabbe's disease. Since banked umbilical
cord blood from unrelated donors is readily available, it is hence used after
myeloablative therapy for treating this disease. Children so treated have had
improved neurological outcome and overall survival. In contrast to untreated
patients, who had overwhelming spasticity, blindness, and early death by one to
two years of age, the newborns who underwent transplantation before the onset
of symptoms maintained normal vision and hearing and normal cognitive
development except for areas influenced by gross motor development. Some have
continued to gain gross motor skills. (10)
CONCLUSION:
The main application of umbilical cord
blood is in curative therapies for a range of diseases. UCB is a promising
alternative source because they are plentiful and are discarded as a byproduct
of birth. Controversies are still on in encouraging public cord blanking and
discouraging the private cord blood banking because most of the treatable
conditions can't use one's own blood.
REFERENCES:
1. Lopez, Angel, "Umbilical Cord Blood
Stem Cells (UCBSC)". Embryo Project Encyclopedia (2010-07-01).
2. Gunning J. (2007). Umbilical cord cell
banking: An issue of self-interest versus altruism. Medicine and Law, 26, 769–780
3. McGuckin CP, and Forraz N. (2008). Umbilical
cord blood stem cells: An ethical source for regenerative medicine. Medicine
and Law, 27, 147–165
4.
Ballen
K, Broxmeyer HE, McCullough J, Piaciabello W, Rebulla P, Verfaillie CM, and
Wagner JE. (2001). Current status of cord blood banking and transplantation in
the United States and Europe. Biology of Blood and Marrow Transplantation.
5.
Frances Verter, PhD, founder and director of
theParent’s
Guide to Cord Blood Foundation.
6. Human umbilical cord blood as a potential
source of transplantable hematopoietic stem/progenitor cells H E Broxmeyer, G W Douglas,
G Hangoc,
S Cooper,
J Bard,
D English,
M Arny,
L Thomas,
and E A Boyse
7. Searching for Alternative Sources of
Postnatal Human Mesenchymal Stem Cells: Candidate MSC-Like Cells from Umbilical
Cord Yuri A. Romanov Ph.D.*, Veronika A. SvintsitskayaandVladimir N.
Smirnov Article first published online: 1 JAN 2003
8. Successful Stem Cell Therapy Using Umbilical
Cord Blood-Derived Multipotent Stem Cells for Buerger's Disease and Ischemic
Limb Disease Animal Model Sung-Whan Kim1, HoonHan2, Gue-TaeChae1,
Sung-Hoon Lee3, Sun Bo3, Jung-HeeYoon4, Yong-Soon
Lee3, Kwang-Soo Lee5, Hwon-Kyum Park M.D., Ph.D.5, *andKyung-Sun
Kang Ph.D., 2003
9. Allogeneic sibling umbilical-cord-blood
transplantation in children with malignant and non-malignant disease JohnE.
Wagner MD, aMichael Steinbuch PhD bNancyA. Kernan MD
cHalE. Broxmayer PhD d (Prof)Eliane Gluckman MD e(Prof),
2003
10. Transplantation of Umbilical-Cord Blood in
Babies with Infantile Krabbe's Disease Maria L. Escolar, M.D., Michele D. Poe, Ph.D.,
James M. Provenzale, M.D., Karen C. Richards, M.D., June Allison, R.N., Susan
Wood, P.N.P., David A. Wenger, Ph.D., Daniel Pietryga, M.D., Donna Wall, M.D., Martin
Champagne, M.D., Richard Morse, M.D., William Krivit, M.D., Ph.D., and Joanne
Kurtzberg, M.D. N Engl J Med 2005
11. Transplantation of Umbilical-Cord Blood in
Babies with Infantile Krabbe's Disease Maria L. Escolar, M.D., Michele D. Poe, Ph.D.,
James M. Provenzale, M.D., Karen C. Richards, M.D., June Allison, R.N., Susan
Wood, P.N.P., David A. Wenger, Ph.D., Daniel Pietryga, M.D., Donna Wall, M.D., Martin
Champagne, M.D., Richard Morse, M.D., William Krivit, M.D., Ph.D., and Joanne
Kurtzberg, M.D. N Engl J Med 2005; 352
