Integration of Host Tissue with Implants

Instead of being acted upon by the body as an impenetrable foreign object, the synthetic bone replacement – currently being tested in rabbits – features a porous material that allows for the delivery of “microencapsulated bioactive cues” that speed up the growth of host tissue at the site and allow for the growth of new bone. A critical finding is that the drug dose needed for host tissue integration by this controlled-release approach is about 1/10 of that by the traditional technique of simple adsorption of the growth factor.

The approach could bring to orthopedics and dentistry a treatment that has wrought much interest and success in the field of cardiology with the development of drug-eluting stents, which take what is ordinarily an inert tube, and infuse it with drugs to make the placement of what is essentially a man-made, foreign object more compatible with the patient’s body, and at the same time, actively promoting healing of injured tissue.

After just four weeks, the porous implants that Jeremy Mao of the Columbia College of Dental Medicine and his team are using showed a 96 percent increase in bone-to-implant contact and a 50 percent increase in the growth of new bone over placebos. Since stem cells play a vital role in the growth of new bone, Mao and his team have focused on impregnating the titanium implants with a factor that “homes” the bodies’ own regenerating cells to the potential growth site to create and build on a platform for new bone.

The new approach may in the future obviate the need to harvest bone from a non-injured site in the body for grafting into the site of injury, as commonly performed now. This strategy, although often effective, creates additional wounds. The work of Mao and his team suggests that it should be possible to harnesses the body’s natural tissue regeneration capacity to recruit the right cells to the site where new bone tissue is needed.; Source: Columbia University Medical Center