Haematopoietic stem cells give rise to blood cells in the body and it is from such cells that researchers in France have created artificial blood used for transfusion in a human volunteer. Blood drives are familiar to many of us and the medical system depends on blood donors to carry out much-needed transfusions during emergency procedures and elective surgery. Where healthy donors are hard to find, such as in countries suffering from an AIDS epidemic, or where matching blood types are scarce the lack of available blood can have devastating consequences. What if we could simply grow blood in the laboratory, matching patients perfectly, and store it for use when needed? An artificial blood supply would never run dry and there would be no need for desperate calls for donors. Could this trial, NCT0929266, the world’s first blood transfusion using stem cells herald a new age of medicine?
World’s First Stem Cell Blood Transfusion
Researchers at Pierre and Marie Curie University led by Luc Douay used haematopoietic stem cells taken from a volunteer’s bone marrow to create fully-formed red blood cells that could be used for transfusion. The artificial blood, grown in the laboratory from stem cells was marked for tracking purposes following transfusion and just a small amount of blood was first injected to test the safety of the procedure. The volunteer received the equivalent of two millileters of blood, containing some ten billion red blood cells which were followed around the body and found to function just as normal cells do, carrying oxygen and surviving for the same amount of time as ordinary blood cells.
Advantages of Artificial Stem Cell-Derived Blood
Happily, no malignant cells arose during the trial, and there was no evidence of other safety concerns. The results, published last week in the journal Blood, have set both the stem cell industry and the world of medicine alight with the possible applications of the procedure in saving lives. Advanced Cell Technology’s Robert Lanza, who was working as part of the first team to create red blood cells on a usable scale in the laboratory has called the trial a huge step forward, especially given the failure of previous attempts to form blood substitutes safe for transfusion.
The authors of the paper, explain how they initially used peripheral CD34+ haematopoietic stem cells and encouraged erythroid differentiation to generate cultured red blood cells (cRBCs). In this recent trial 94-100% of the red blood cells were still in circulation after five days, with 41-63% surviving after twenty-six days making them comparable to normal red blood cells. These cells were picking up and dropping off oxygen just like ordinary, ‘homegrown’, red blood cells, and the team also examined their functionality in terms of enzyme content, and expression of blood group antigens. Douay has said that the results “show promise that an unlimited blood reserve is within reach” but there remain considerable problems to overcome before the method can be routinely used or even sent for rigorous testing as a stem cell treatment.
Problems with the Technique
As people live longer and have more elective procedures as well as emergency or essential operations, the need for blood keeps on growing. An estimated 90 million-plus units of blood are transfused worldwide, but a standard blood transfusion procedure requires around 200 times the amount of blood used in this experiment. This means that the researchers would need around 400 liters of the fluid used to grow the cells and improvements to the technique are necessary, therefore, before the use of artificial blood grown from stem cells becomes realistic. Meanwhile, other researchers may be looking at the use of embryonic stem cells, cord blood stem cells, and even skin stem cells to create large amounts of laboratory-grown blood for transfusion. Embryonic stem cells may be able to grow ten times the amount of red blood cells as achieved by Douay. Developing a technique using the patient’s own cells appears optimal however, given the concerns, both practical and ethical, over the use of embryonic stem cells, and cord blood stem cells, with potential problems of abnormal cell development or immune system rejection.
Disadvantages to Artificial Blood from Stem Cells
One problem with stem cell derived blood for transfusion however is that it still requires refrigeration, just like ordinary donor blood. This presents some serious problems for those working in disaster areas, such as after major earthquakes where power is unavailable and supplies of healthy fresh blood are hard to acquire. As such, researchers Chris Cooper at the University of Essex in the UK has been working on an artificial blood substitute based on haemoglobin but which does not require refrigeration. Cooper admits that the stem cell artificial blood has distinct advantages over the product he is developing as it is more like a real red blood cell transfusion.
A Blood Cure for HIV/AIDS?
Following the publication of the paper there has been speculation that the technique may be able to be used in developing a cure for HIV and AIDS. The reasoning is that the blood may be grown from stem cells taken from donors making up the 1% of people thought immune to HIV. Then patients living with the virus may be given transfusion that could rid their body of the infection. However, the hopes of such a treatment are almost certainly set to be dashed as only a very small number of people will be a match for those 1% from whom such a transplant could arise. Most of this group, immune to the Human Immunodeficiency Virus (HIV) are eastern European, which would cause significant problems in matching the donors to those in African countries, for example, where the majority of AIDS patients live. Even without the promise of a cure for AIDS and HIV using this technique, the ability to grow artificial blood from stem cells offers an opportunity to revolutionize medical practice and save many lives.
References
Giarratana MC, Rouard H, Dumont A, et al. Proof of principle for transfusion of in vitro generated red blood cells. Blood 2011;118(19):5071-5079.
