TMDU researchers develop new double-layered cell transfer technology for effective bone repair

Various technologies have been developed to introduce laboratory-grown bone-forming cells into bone defects to promote their repair. However, these have many limitations as the conditions of the cells and their surroundings do not accurately mimic those typically found in the body. This means they cannot optimally promote bone formation. A research team at Tokyo Medical and Dental University (TMDU) has now made a major advance in overcoming these difficulties by developing a technique for producing double-layered cell constructs that can be transplanted onto bone defects. The technique increases the speed of bone repair and the flexibility and durability of the constructs make them ideal for many surgical applications.

Cells with various functions can now be cultured in the laboratory and then introduced into the body to treat different medical conditions. However, as individual cells can spread away from the site of injury, they need to be held in place on a scaffold, which is then transplanted into the body. Substantial progress has already been made in this sort of tissue engineering. When the body repairs broken or damaged bones, it employs a complex system of molecular signals and cells, including osteoblasts that build up the calcium matrix on which bone is based. To speed up the repair of bone defects by artificial means or enable recovery from severe injuries, tissue engineering approaches thus need to mimic this complex system.

"After establishing our double-layered cell transfer technology, we used it to apply different combinations of cells related to bone formation to defects in mouse skulls," first author Keiko Akazawa says. "We found that osteoblasts together with stem cells from tooth-supporting ligament were particularly effective at promoting bone repair than equivalent scaffolds containing only a single cell layer."

The double-layered cell constructs were also tested for their stability and flexibility. The cells remained attached despite folding the constructs or trimming them to fit the shape of a particular defect. Coauthor Kengo Iwasaki says: "The durability of these new constructs makes them particularly suitable for surgical applications. We have high expectations for their use in regenerative medicine for treating a range of defects using different cell layer combinations."