Two new bone tissue engineering methods are featured in the September issue of Nature Biotechnology.
Bone grafts typically are used to repair fractured or defective bones. The procedure, however, involves removing bone from one part of the patient’s body and transferring it to another, which often is painful and can present complications. Additionally, large bone defects can be hard to treat because scarring, rather than healing, occurs.
French researchers studied whether large fractures could be treated using sea coral grafts seeded with bone cells. Sea coral contains calcium carbonate and has a porous architecture not unlike that of natural bone. Researchers showed that it could be used to grow mes-enchymal stem cells, or MSCs, a type of primitive cell derived from bone marrow that can be grown easily in culture.
They implanted sheep that had 25-millimeter lesions in their hoof bones with the coral alone or with coral infiltrated with either expanded MSCs or fresh bone marrow. After four weeks, the bone marrow had biodegraded. After 16 weeks, the fractures implanted with the MCS/coral combination showed extensive bone remodeling and, in some cases, fusion with the native bone on either side of the implant. In untreated animals and animals treated with coral alone or coral and fresh bone marrow, the fracture failed to heal.
In the second article, American researchers describe how they cultured bone cells so that they rapidly formed organized crystalline bone in a petri dish.
When bony precursor cells derived from bone marrow cells were exposed to transforming growth factor-b, they aggregated, began forming bone-specific proteins and produced crystalline structures that contain human bone within three to five days. Researchers said this result was striking, as the microspicules had an organized bone structure, which had been difficult to achieve using other approaches.
Researchers believe that the ability to culture bone in the laboratory will be important for understanding bone formation biology, and the technology could be used in clinical bone engraftment applications.
