We often come across announcements stating that blood is needed in the flow of our daily lives. We hear announcements for blood donations for those injured in traffic accidents or undergoing surgery.
Blood is a vital fluid produced only by humans. Efforts are underway to produce blood in laboratory settings as a source of life’s energy.
Approximately three million transfusions of red blood cells, referred to as erythrocytes, and 500,000 transfusions of platelets, known as thrombocytes, are required annually in Germany.
These two components, along with other constituents, float in the liquid blood plasma and cannot be sufficiently generated by some individuals anymore. This can be due to treatments such as chemotherapy or radiation for tumor therapy, as explained by transfusion doctor Torsten Tonn from TU Dresden, for example: “In cases like leukemia, after high-dose chemotherapy, patients often lack platelets.”
For individuals in the stage of hematopoietic disorders, appropriate blood products should be urgently provided, often requiring several hundred blood transfusions per patient. Additionally, individuals with specific blood disorders such as sickle cell anemia rely on regular blood donations. Blood is also frequently needed after severe accidents or certain surgeries. Without red blood cells, oxygen cannot enter the body’s organs and vessels, and without platelets, wounds and injuries cannot heal as blood clotting cannot occur. Therefore, researchers have been working tirelessly for years to artificially produce these blood components in the laboratory.
Cells without a nucleus
Red blood cells and platelets are different from other cells in the body because they lack a nucleus. This characteristic makes them flexible and elastic, allowing them to reach the smallest blood vessels. However, for researchers, this biological feature poses a significant barrier in cell cultivation, as explained by transfusion doctor Tonn. The reason is that “it is very challenging to visualize this in cell culture outside the body because removing the nucleus is highly complex.” During their development in the bone marrow, blood cells go through different stages of maturation, and in the final stage, they lose their nuclei.
Is imitation possible?
Various teams have already succeeded in mimicking this process in the laboratory, but only in very small quantities. For example, in Dresden, Tonn’s team managed to produce a vial filled with red blood cells. However, this is still less than one percent of a traditional blood transfusion. Even on an international level, the production of artificial blood products is not yet highly efficient. A team at the University of Bristol administered artificially produced red blood cells to two patients in the fall of 2022. There were no rejection reactions or other side effects, but the amount of transfused blood was only about two to three teaspoons.
All blood types are not the same
According to Dresden researchers, the production of artificial blood cells could offer a way out for the care of many patients in critical conditions. For a transfusion to have medical significance, the blood types and many other characteristics between the donor and recipient must match. If it becomes possible to produce blood products in the laboratory with the help of genetic engineering, this problem could be solved.
Previous approaches to the development of erythrocytes and platelets in the laboratory have only been moderately successful. Therefore, scientists are now pursuing a different research focus. For example, Tonn and his team in Dresden are working on growing the progenitors or parent cells of red blood cells. These cells still have nuclei, and the idea of the researchers is to leave the removal of the nucleus to the organism as the final step. In other words, it involves shortening the development of cells and transferring immature blood cells that have not fully matured. By doing so, the step of enucleation would be skipped, presenting a challenge for scientists.
Research on the precursors of platelets
A team from the Hannover Medical School is growing the progenitor cells of platelets, says transfusion doctor Rainer Blasczyk: “We can produce platelets, but it is easier to grow the progenitor cells of platelets, known as megakaryocytes, for example, in giant nuclear cells. And our idea is to make them the basis of transfusions instead of platelets.” The research team from Hannover has already succeeded in developing such artificial progenitor or giant nuclear cells, adds Constanza Figueiredo from the Institute of Transfusion Medicine in Hannover. And “on a small scale and also in large bioreactors. That’s why we can produce enough of these cells that are required for a transfusion.” In animal experiments, the team from Hannover has already been able to demonstrate that this approach works. The organism continues to generate progenitor cells in platelets. The researchers are now preparing for the first clinical trials. It will likely take a few more years for artificially produced blood to become truly available. Therefore, regular blood donations from the population are indispensable to ensure the best possible blood supply for those affected.