Friday, October 28, 2011

Method to artificially produce blood is ready

We may very well be producing blood by ourselves soon, without the need to tap it from volunteers. Scientists in Edinburgh, Scotland have found a way to produce blood by using stem cells. They would only need two to three years to start tests in humans. If it all works, the artificial blood could be used in situations of acute blood loss, surgery, and other reasons that involve the rapid administration of extra blood to a patient. Because we currently rely heavily on donors, finding artificial ways for blood production is an important step forward.

Red blood cells
The blood is derived from stem cells that reside in the bone marrow. These somewhat specialized cells are able to divide while retaining their regenerative characteristics: the daughter cell can divide into whatever blood cell is needed, while the parent retains its stem cell characteristics. Every second, the body produces a stunning 2,4 million erythrocytes, also known as red blood cells. This highlights the enormous cell producing capabilities that these hematopoietic stem cells (HSC) have. The Scottish researchers have found a way to use HSC outside of the body, and let them produce erythrocytes, as they normally would. The produced red blood cells are consequently put in a mix that can be used as blood.

In the lab, the HSC produce blood that is O negative, the blood type that is commonly described as the 'universal donor'. That is because the blood does not contain the 'labels' A or B, which can be recognized by the host's defense system, which consequently causes inflammation, to destroy the foreign cells. Because O negative has no labels, and no so-called Rhesus factor, the body's immune system stays silent. This way, almost everybody can receive the produced blood. In addition, people that possess blood type AB are sometimes called universal recipients, as their body does not recognize the labels A and B as foreign, because they possess it themselves.
Erythrocytes are cells that the body uses to transport oxygen: they possess a special molecule called haemoglobin that contains iron to bind oxygen molecules. Interestingly, red blood cells do not have a nucleus, while most other cells in our body do. In the nucleus, cells store the genetic information in structures called chromosomes. Naturally, blood contains more than just erythrocytes. White blood cells, that have a function in the immune system, roam the blood, and platelets are required for coagulation when a blood vessel is ruptured causes bleeding. Many more molecules, like glucose, are transported by the blood. Sometimes in a free form, sometimes bound by proteins.

Artificially produced blood can be a life saver in situations that require acute supply of blood, and surgeons often use it in the hospital. For example, blood loss during surgery needs to be countered by administering extra blood, to keep the blood flow and supply of nutrients to all parts of the body going.

Because the blood producing method has not yet been tested in humans, it will still take several years before doctors can actually use artificial blood. But the development of a method that makes it possible is a big step in the right direction. 

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