A team at Tokyo Medical and Dental University, Japan has stimulated bone growth in mice jaws by injecting a solution into them. The part of the jawbone containing tooth sockets is known as alveolar bone, and its loss over time or following dental disease may ultimately result in tooth loss. While dentures can be used as tooth replacement, the mechanical stimuli under them causes further bone loss. An alternative and more permanent solution is strongly hoped for.
Human bone morphogenetic protein 2 (BMP-2) has been used to stimulate bone formation in humans, but high levels can cause inflammation and tumours. Therefore, agents such as peptide drugs for accelerating bone augmentation need to be developed, even in the presence of lower levels of BMP-2. Additionally, there are no known means of stimulating local bone augmentation without performing surgery.
The peptide OP3-4 has been shown to inhibit bone decay and stimulate the differentiation of cells that form bone. The team in Tokyo injected a gelatin-based gel carrying OP3-4 and BMP-2 into mice jawbones to trigger local augmentation of bone around the injection site. The study was recently reported in the Journal of Dental Research.
Use of this injectable gel to carry the agents avoids the need for surgical implantation and resulted in no swelling or other such complications in the mice. The researchers observed a region of increased bone mass around the injection site that was larger than that seen in mice injected with BMP-2 alone. This mass also had a significantly higher bone mineral content and density.