Umbilical cord blood transplants from inception to modern day
The umbilical cord acts as a conduit between the developing foetus and the placenta. It is this that allows the baby to gain the nutrients that it needs including oxygenated rich blood from the placenta. Within the umbilical cord, there are two arteries and one vein buried beneath a fleshy substance that is known as Wharton’s jelly. It develops from the remnants of the yolk sac and will be fully formed by the 5th week of fetal development. It is connected to the developing foetus via the abdomen and will form the belly button after birth. The blood flow through the umbilical cord will increase as the baby develops, in the beginning weeks, it is expected to be around 35ml and at the end of the gestation period, it will be around 240 ml. When delivered, the umbilical cord will measure approximately 50 centimetres in length and about 2 centimetres in diameter. For many years, the umbilical cord was simply discarded after birth, however, this all changed in the 1980’s. The year 2014 saw the 25th anniversary of the first umbilical cord transplant which was conducted in France on a child suffering with Fanconi Anaemia. Over the past 25 years, the field of umbilical cord blood transplants has grown dramatically and in fact, as many as 6 million units have been stored for transplantation across the globe.
The History behind Umbilical Cord Blood transplantation
Umbilical cord blood is much more than just the normal make up of blood including red blood cells, white blood cells, plasma and platelets. It is also a rich source of stem cells. In particular, cord blood stem cells are known as hematopoietic. These particular kind of stem cells are so incredibly sought after because they are almost completely immature, meaning that their reproductive properties are extremely good and there is a much lower chance of the recipients body rejecting the cells. The knowledge that umbilical stem cells could be a rich source of cell regeneration and help to defeat many genetic disorders began in 1982, when a Mr. Edward Boyse decided that simply discarding the blood of the umbilical cord after birth was completely wasteful and he was confident that he could find a better use for it. Boyse’s original idea was that, the blood could be used as a source of mature cells for blood transfusion. This idea didn’t quite work out, however, another doctor decided to throw his two cent into the mix and suggested that the blood could be used as a source of transplantable hematopoietic stem. This suggestion prompted the formation of the Biocyte Corporation, a collection of many doctors and medical researchers who studied the benefits of cord blood. This Corporation conducted the first fully funded medical research study on umbilical cord blood and its uses. The study provided the scientific basis of the benefits of cord blood which continues to be of use today.
The Scientific Basic of Cord Blood
The stem cells contained within umbilical cord blood are essentially very similar to the stem cells found in bone marrow. However, there are some key differences. Umbilical cord blood has an extensive proliferative capacity that exceeds that of bone marrow. The stem cells present in umbilical cord blood are also extremely strong. These cells can easily survive transportation and can be cryopreserved and thawed without any damage at all to the cells. In fact, healthy umbilical cord blood can be preserved for as long as 20 years with recovery of the stem cells still possible.
Current Cord Blood Transplantation Treatments
Cord blood is mainly used to treat children with cancerous blood disorders like leukaemia and also other blood disorders are genetic such as Fanconi anaemia. The cord blood is transplanted into the patient in order for the regenerating stem cells to replace the old cells that have been damaged by the disease with new healthy bloody cells. It’s becoming used more widely because it is a much better alternative to bone marrow stem cell transplants. Stem cells from umbilical cord blood are extremely easy to collect and many parents choose to donate theirs at the time of delivery, increasing the amount of stores available for children suffering from terrible and debilitating diseases. Bone marrow stem cells on the other hand, are difficult to collect and the procedure can be extremely dangerous for the donor. With bone marrow stem cells, there is also a much higher chance of the recipient body rejecting the cells, this is known as graft versus host disease. Some matching is still necessary with cord stem cells, however, there is no need for it to be an exact match as the cells are still very immature and therefore, have a greater ability to adapt to the host’s body. However, when it comes to bone marrow transplants almost an exact match is needed which means many people could go without the transplant they desperately need because a match cannot be found. As with all medical procedures, there are of course, limitations when it comes to umbilical cord blood transplants. Although the procedure has proved to be very effective in children, so far, treatment of adults has proved to be extremely challenging and fraught with failure. As well as, so far, umbilical cord blood has only been used to treat blood diseases, although, research into wider uses is currently being conducted.
Current Umbilical Cord Blood Research into Blood Diseases
One of the core limitations of umbilical cord blood transplantation is that the blood that can be gathered from one single umbilical cord does not contain as many stem cells as a bone marrow donation does. It is for this reason that researchers believe adult transplantation has so far proved to be very difficult. Obviously, adults are much larger than children and therefore, they will need many more stem cells to complete the same task. If a transplant does not have enough stem cells, then the results could be complete failure or very slow new blood cells formation. One solution to this problem is to use the blood from more than one umbilical cord for an adult transplantation, however, this can cause difficulties because the cells will be slightly different due to genetic differences. Another solution is to not only take blood from the cord at the time of birth but to also take blood from the placenta. However, so far, neither of these solutions has proved to be completely satisfactory. Therefore, most of the research into umbilical cord blood and blood diseases is focused on trying to increase the number of stem cells that can be gathered from one sample. This research primarily involves attempting to grow and multiply the cell in a laboratory. This process is called ‘ex vivo expansion’. At this point, the results are very mixed, although the process can enable the new blood formation process to speed up in adult hosts in most cases, adults still require the blood from at least two umbilical cords for the transplantation to be a success.
Current Umbilical Cord Blood Research into Other Diseases
The standard medical view is that the stem cells retrieved from umbilical cord blood are only useful for treating blood diseases. This is due to the fact that these particular stem cells are only able to mature into full blood cells, and they do not have the ability to regenerate into other kinds of tissue like embryonic stem cells are. However, there are several research teams that beg to differ. Studies conducted on animals have suggested that cord blood can repair far more than simply blood diseases. The team has even suggested that these stem cells can be used to help people recover from heart attacks and strokes. These reports are unsurprisingly very controversial as the scientific basis of the results is currently unclear. It is also possible that the beneficial effects observed were very minor and therefore, not significant enough to be developed into treatments. Another possible explanation is that the blood cells don’t actually heal the damaged cells but they release substances which enable the body to repair the damage itself. This research is still on going and many more researchers are aiming to establish whether safe and effective treatments for non-blood diseases can be developed using cord blood. However, there is more promising research in other field of health. Recently, clinical trials have been conducted in which umbilical cord blood is used to treat children suffering from various brain disorder such as cerebral palsy and traumatic brain injury. Disorders like this are caused by a lack of oxygen reaching the brain, therefore, in theory, the oxygen-rich umbilical cord blood should be able to repair some of the damage by adding much needed oxygen to the affected area. These trials are still at a very early stage and much more research is needed before full treatments can be developed, however, the current results look very promising.