A technique to grow 3D tissue constructs, similar to human bone, in a laboratory environment has been developed by bioengineers at NASA Johnson Space Center. Problems arise when studying both the normal state and pathophysiology of bone. The ability to construct a 3D model of such mineralized tissue on-demand is a major step forward in how the process of bone formation and remodeling can be studied.
One of the central objectives of this project was the development and characterization of a 3D mineralized tissue model system in which the effects of mechanical load (e.g., compression loading, tension, vibration, etc.) on the cellular responses of osteoblasts and osteoclasts could be investigated. After introducing mineralization agents to the culture, the constructs take on a bonelike appearance and have a more rigid structure suitable for being tested.
Testing of the mineralized constructs confirmed the presence of calcium through a crystalline matrix histochemical stain. The central core is void of necrotic material, instead filled by a crystalline matrix with embedded nucleated cells. Remarkably, the nucleated cells do not express osteoblast markers, indicating differentiation to the in vivo cell type known as the osteocyte.
In addition, as is characteristic to native periosteum, osteoclast precursor cells were imaged and proven to naturally arrange as an outer layer of the mineralized bone tissue construct. Development of this model will provide a unique venue for testing proposed countermeasures to space flight-induced bone loss. It will also allow a mechanistic approach in the modulation of cell signaling at the cellular level within the bone matrix.
Applications include orthopedic research and product development of medical devices, drug discovery, as well as bone function and formation studies.