January 12, 2014
New Treatment For Blood Diseases Using Artificial Bone Marrow
Rebekah Eliason for redOrbit.com - Your Universe Online
Specialized cells, known as hematopoietic stem cells, located within bone marrow, continuously replace and supply new blood cells such as red blood cells and white blood cells. Traditionally a blood disease like leukemia is treated with bone marrow transplants that supply the patient with new hematopoietic stem cells. Researchers have now discovered a way to artificially reproduce hematopoietic stem cells.
Since not every leukemia patient can find a suitable transplant, there is a need for other forms of treatment. The lack of appropriate transplants could be solved by artificial reproduction of hematopoietic stem cells. Previously, reproduction of the cells has been impossible due to their inability to survive anywhere but in their natural environment. Hematopoietic stem cells are found in a special niche of the bone marrow. If the cells reside out of the bone marrow, the specialized properties are modified. Consequently, to effectively reproduce the cells, the stem cell niche environment must also be created.
In the microscopic environment of the stem cell niche, there are several specific properties of importance. Areas in the bone that house the stem cells are extremely porous like a sponge. Making things even more complex, the spongy tissue is also home to other cell types which exchange signal substances with the stem cells. Also, the space among the cells creates an environment ensuring stability along with a place for the cells to anchor. Furthermore, the stem cell niche supplies the cells with nutrients and oxygen.
Dr. Cornelia Lee-Thedieck is head of the Young Investigators Group “Stem Cell-Material Interactions,” which consists of scientitsts from the KIT Institute of Functional Interfaces (IFG), the Max Planck Institute for Intelligent Systems, Stuttgart and Tübingen University. The team was successful at artificially reproducing major properties of bone marrow at the laboratory.
Using synthetic polymers, the researchers were able to create a porous structure that simulated the spongy environment of the blood-forming bone marrow. Also, they were able to add protein building blocks which are similar to those found naturally in the environment of the bone marrow that enable cells to anchor. Finally, they added the other types of cells needed for exchanging signaling substances.
After the artificial bone marrow was created, the scientists placed hematopoietic stem cells that had been isolated from cord blood into it. For several days the cells were bred. Various analytical methods were then used to determine that cells were able to reproduce in the artificial bone marrow. When compared with standard cell cultivation methods, a larger number of stem cells in the artificial bone marrow retained their specific properties.
Since the developed artificial bone marrow contains major properties of natural bone marrow, scientists can use this new substance to study in detail the interactions between specific substances and stem cells. This specially created research tool will enable scientists to discover how the behavior of stem cells is influenced and controlled by synthetic materials. In ten to fifteen years, this knowledge could play a contributing part in production of an artificial stem cell niche specifically designed to reproduce stems cells for the treatment of leukemia.
The research has been accepted for publication in the journal Biomaterials.
Image 2 (below): A synthetic scaffold structure similar to the bone is placed into a vessel for the cultivation of stem cells. Credit C. Lee-Thedieck/KIT