Story of Cord Blood Storage
History
Science
Private Banking
The Use of Autologous Cord Blood
Summary
History
Interest in the properties of cord blood cells began in the 1970's and led to the first transplant of cord blood in 1979, using blood collected from a newborn sibling to treat a boy with a fatal disease, Fanconi's anaemia. This cord blood transplant was successful and resulted in proposals to establish cord blood banks to store stem cells for treating unrelated recipients. Public banks were established in a number of countries and slowly began to be utilized for the treatment of a range of bone marrow disorders, until today there are many hundreds of thousands of samples stored, and more than 10,000 cord blood transplants have been performed.
Science
These transplants make use of the presence of haematopoietic stem cells (HSC's) in cord blood, similar to the cells present in bone marrow that give rise to red and white blood cells. In effect, therefore, cord blood is an alternative source of cells for what was previously known as a bone marrow transplant. However, the increasing attention of scientists in cord blood that followed from these initial breakthroughs has led to the realization that cord blood contains a number of different cells with unique and valuable properties. A number of groups have identified a population of unrestricted stem cells, capable of giving rise to many different cell types such as muscle, nerves and bone. Cord blood is also a source of unique populations of immune cells, called regulatory T-cells, that are important in controlling the immune system and may have therapeutic potential in the treatment of immune disorders such as diabetes.
Private Banking
Private cord blood banking arose as a concept because of the realisation that these unique cell populations may have a range of therapeutic uses in the future. Importantly, the cells collected at birth differ in a number of important ways1 from stem cells collected later in life, so there is only one chance to collect them. Of course, these arguments, based on early stage science and animal studies rather than proven clinical effect, have been criticized on the basis that there is no clinical proof that such therapies will be developed in the future. But it is important to realize that exactly the same criticism was made of public banks when they were first proposed - there was little or no clinical evidence that unrelated cord blood would be a suitable source of cells for HSC transplant when the first banks were being established. There is an inescapable "catch 22" here - it is not possible to undertake the clinical studies to show the efficacy of stored cord blood cells without first developing the banks to store them.
The Use of Autologous Cord Blood
The diseases currently being studied are many times more common than leukaemia or other bone marrow diseases that might be treated with HSC transplantation. For example, 1 in 200 children will develop type 1 diabetes, and 1 in 500 will be diagnosed with cerebral palsy by the age of five years.
This is only the beginning of the development of new therapies. For example, in animal models, cord blood is effective in significantly improving function after spinal cord injury.
Many of the effects being seen are almost certainly not due to the HSC's present in cord blood. The efficacy in diabetes, for example, is believed to be due to the presence of regulatory T-cells in cord blood, which suppress the autoimmune disease causing destruction of the insulin producing cells. If this is shown to be the case, then these cells may have a therapeutic role in a wide range of autoimmune diseases. And these treatments will only be possible using the patients own cord blood cells - for the reasons mentioned above, unrelated cord blood cells from a public bank will not work.
Because the storage of these cells can be lifelong2, it is not only pediatric diseases that need to be considered. Just as publicly banked cord blood is increasingly being used as a source of HSC's for transplantation in adults, it is to be anticipated that privately stored cord blood will eventually be used in the treatment of the donors as they grow into adulthood. But, again the catch 22 - this can only be demonstrated many years after the decision to store the cord blood.
The constantly evolving uses of cord blood make any estimates of the "probability that the cord blood will be used" meaningless at this time. As the list of diseases treatable with cord blood increases, and the age at which donors receive those treatments increases, the likelihood that a sample will be used will increase.
NB: The studies described above are in early trial stages and may never be available for routine treatment.
Summary
In summary, private cord blood banking is a valid birthing choice for parents who:
- Cannot access or are ineligible for public banking
- Accept the available evidence that Cord Blood Stem Cells have clear differences (and advantages) over cells collected later in life
- Believe that advances in medical science have the potential to yield new therapeutic treatments using cord blood, particularly ones which will utilize fully compatible cells
- Are prepared to make an investment in their family's future on this basis, with the clear understanding that such an investment is speculative but with a potentially high return
28 November 2008
Professor Mark Kirkland
Australian Stem Cell HealthCare
1 Eg reduced exposure to environmental mutations, longer telomeres (a kind of internal clock within the cell that limits the cells ability to divide), reduced aging ("epigenetic changes"), immunological differences, greater proliferative potential
2 There is currently no known limit to the storage life of cells kept in liquid nitrogen