Status: 08.03.2023 05:33
Many people are dependent on blood donations because of illnesses or accidents. But this is often lacking, especially with rare blood groups. Would artificial blood from the laboratory be the solution?
By Daniela Remus, NDR
Blood is urgently needed: Around three million transfusions with red blood cells, the so-called erythrocytes, are needed in Germany every year, as well as 500,000 transfusions with blood platelets, the so-called thrombocytes.
Required after chemotherapy or accidents
These two solid blood components swim, along with other components, in the liquid blood plasma and can no longer be formed sufficiently by some people. This can be caused, for example, by tumor treatment with chemotherapy or radiation, as Torsten Tonn, transfusion doctor from the TU in Dresden, explains with an example: “Patients after high-dose chemotherapy, such as that used for leukemia, often no longer have any blood platelets themselves .”
For the phase of the haematopoietic disorder, these people urgently need to be supplied with suitable blood products. And this often requires several hundred blood transfusions per patient. In addition, people with certain blood disorders, such as sickle cell anemia, depend on regular blood donations.
Blood is also often needed after serious accidents or some operations. Because without erythrocytes, no oxygen can get into the organs and vessels of the body, without thrombocytes wounds and injuries do not heal because the blood does not clot. For this reason, researchers have been working intensively for years to artificially produce these blood components in the laboratory.
cells without a nucleus
Erythrocytes and thrombocytes differ from other body cells in that they do not have a nucleus. This makes them supple and elastic and allows them to get into the smallest blood vessels. For the researchers, however, this biological peculiarity poses a major hurdle when growing the cells, explains transfusion medicine specialist Tonn, because it is “very difficult to image this in cell cultures outside the body. Because getting rid of the nucleus is very complex.”
During their development in the bone marrow, the blood cells go through different phases of maturation. In the last they lose their cell nucleus.
imitation possible?
Various teams have already succeeded in mimicking this process in the laboratory, but only in very small amounts. In Dresden for example, Tonn’s team was able to produce about a thimble full of erythrocytes. That’s no more than about one percent of a traditional blood transfusion.
And internationally, too, the production of artificial blood products is not yet very efficient. A team at the University of Bristol administered artificially produced erythrocytes to two patients in autumn 2022. There were no rejection reactions or other side effects, but the amount of blood transferred was just two to three teaspoons.
Blood is not just blood
The production of artificial blood cells for the care of many patients could be a way out of their plight, according to the Dresden researchers: Because the blood groups and many other characteristics of the donor and recipient must match for a transfusion to make medical sense. If it were possible to use genetic engineering to produce precisely tailored blood products in the laboratory, this problem could be solved researchers.
Previous attempts to develop erythrocytes and thrombocytes in the laboratory were only moderately successful. That is why scientists are now pursuing a different research focus. In Dresden, for example, Tonn and his team are working on growing the progenitor or mother cells of the red blood cells. This is the name given to the cells from which the mature blood cells later develop.
These cells still have their cell nucleus, and the researchers’ idea is to leave the last step, ejecting the cell nucleus, to the organism. So to shorten the development of the cells and to transfer blood cells that are not yet fully mature. Then the gutting step would no longer be a challenge for the scientists.
Research on platelet precursors
A team from the Medical University in Hanover is growing the precursor cells of the thrombocytes, explains transfusion doctor Rainer Blasczyk: “We can indeed produce thrombocytes, but it is easier to grow the precursor cells of the thrombocytes, the so-called megakaryocytes – in English giant nucleus cells. And our idea is to make that the basis of transfusions instead of platelets.”
The research team from Hanover has already succeeded in creating such artificial precursors or developing giant nucleus cells, adds Constanza Figueiredo from the Institute for Transfusion Medicine in Hanover. In fact “on a small scale and also in large bioreactors. And that’s why we can produce enough of these cells that would be necessary for a transfusion.”
The team from Hanover has already been able to show in animal experiments that this approach works. That the organism develops the progenitor cells into platelets. Now the researchers are preparing first clinical studies before.
It will probably be a few more years before artificially produced blood is actually available. Regular blood donations from the population are therefore indispensable in order to ensure the best possible blood supply for those affected.
