Miracle of Stem Cell Therapy
by Dr. Musa Mohd. Nordin
There is universal interest in discovering and developing a permanent source of cells which would be capable of generating any cell type and which would avoid the problem of transplant rejection. These cells called human stem cells have the unlimited capability to divide and the potential ability to develop into most of the specialized cells or tissues of the human body.
Human stem cells can give rise to many different type of cells, such as muscle cells, nerve cells, heart cells and blood cells. They could therefore be potentially useful to generate replacement cells and tissues to treat many conditions including Parkinson’s disease, Alzheimer’s disease, leukaemia, stroke, heart attack, diabetes multiple sclerosis, rheumatoid arthritis and spinal cord injury.
There are 2 major sources of stem cells.
a. Adult stem cells. They are derived from aborted fetuses, umbilical cord blood, bone marrow, blood and brain. They are less plastic (less able to differentiate into specialized cells compared to embryonic stem cells); scarce and sometimes inaccessible (in brain, retina of eyes).
b. Embryonic stem cells. They are derived from embryos as a result of in-vitro fertilization (surplus or created embryos) or from embryos created by somatic cell nuclear transfer (cloning technology). There is an unceasing moral and ethical debate on the use of embryos for research.
Cord blood is a relatively rich source of haemopoietic stem cells (HSC). About 100 mls can reconstitute the haemopoietic system in small patients; usually children.
The first successful related cord blood transplant was undertaken 16 year ago. Since then, over 3,000 transplants have been done worldwide. There are a few reports of successful transplantations of adults.
The advantages of cord blood over bone marrow or peripheral blood transplantation are:
1. The donor does not have to be admitted to undergo collection procedures which may involve mobilisation of stem cells using drugs eg cyclophosphamide and G-CSF ( in case of peripheral blood donor) and anaesthesia ( in bone marrow donor)
2. Unlike the other two sources, cord blood has a reduced risk of graft versus host disease.
There are currently no clear guidelines locally to address the issue of cord blood collection and cord blood banking for future transplantation.
The National Blood Bank has already been collecting and banking cord blood as part of their non-profitable National Cord Blood Bank. The National Cord Blood Bank would be available to doctors to search the public registry for possible unrelated but matched samples as an alternative source for stem cell transplantation.
The issue is clouded further by the sales pitching and often non-evidence based medicine claims of private cord banks. The American Academy of Paediatrics warns that families may be vulnerable to “emotional marketing” at the time of birth of their child. Professor Nick Fisk, Chairman of the Royal College of Obstetrics & Gynaecology Scientific Advisor Committee said “We are concerned that commercial companies are targeting pregnant women with such emotive literature when the scientific evidence is not yet there to back up their claims”.
The risks of a child developing a disease which may require cord blood transplantation is not known. There are no accurate estimates on the likelihood of children requiring their own stored cells. The best guess of this ever happening ranges from 1 in 1,000 to 1 in 200,000. There is therefore only a tiny and remote chance of children ever requiring to utilize their own stored cells.
Scientific indications for collection and banking of cord blood are far and few in between. In families where there is a known genetic disease that can be treated by HSC transplantation, cord blood collection and storage are recommended for siblings born into these families. Cord blood collection is also recommended in specific settings eg
1. A sibling who is suffering from leukemia, just in case he relapses and may require HSC transplant
2. A sibling in whom HSC transplant is indicated but has no match related donor available.
The storing of cord blood privately by private cord banks is based on the premise that the sample is stored specifically for use within the family concerned and more specifically the child’s own future use (autologous transplant).
Autologous transplantation itself maybe problematic because the use of one’s own stem cells may not cure the underlying pathology. In the case of leukaemia and other congenital disorders eg Thalassaemia and Fanconi’s Anaemia; transplanting ones own stem cells with the defective genetic and immune structure (thus causing the disease) would only be returning the disease to oneself.
The 80-100ml of umbilical cord blood collected at birth may not be adequate when the baby grows into an adolescent or adult. The volume of cells is insufficient if he should ever require it later in life.
Thus, the concept of a ‘biological insurance’ which is much hyped by the private cord banks is therefore actuarially unsound given the very low estimates on the likelihood of use, or the need of using one’s own cord blood for transplantation. The emotional marketing is however burgeoning the bank balances of private cord banks.
In the final analysis, public cord blood banking should be expanded for the benefit of the wider population. Collection of altruistic donations of cord blood and directed donations for families at high risk should be encouraged. The National Cord Blood Bank was set up to achieve these objectives at no cost. Rather than just to keep the cord blood banked for one’s own use, it should be made available to others who may need the cord blood in the allogenic (genetically different) setting.
Dr. Musa Mohd. Nordin
Consultant Paediatrician & Neonatologist
musamn@gmail.com