Researchers have developed a new bone graft method consisting of gene therapy coupled with FDA-approved ultrasound and microbubbles. This method, they suggest, completely healed nonunion fractures in pigs within 8 weeks of treatment.

Broken bones that fail to heal properly result in nonunion fractures, leading to long-term hospitalization, disability, and considerable costs to the health system.

Bone graft procedures are performed in an attempt to treat such fractures. However, harvesting fresh bone from patients is often painful, and donated grafts from tissue banks frequently fail to integrate, according to a media release from the American Association for the Advancement of Science.

The new bone graft method, devised by Maxim Bez and colleagues, is described in a study published in Science Translational Medicine.

The researchers first placed a collagen scaffold at the site of the break to provide a welcoming niche for bone progenitor cells. Next, they injected microbubbles mixed with genetic material for a bone growth factor. Pulses of sound from an ultrasound wand promoted uptake of the growth factor DNA by progenitor cells, which stimulated bone growth.

Unlike other gene therapies that rely on viral vectors to deliver their cargo the ultrasound and microbubbles didn’t appreciably trigger inflammation, and expression of the introduced gene was undetectable after 10 days, the release explains.

The technique was proven to be minimally invasive, safe, and promoted total bone healing, with comparable strength to gold-standard graft procedures.

Bez and the investigators conclude in the release that with further development, their system has the potential to be used in many different tissue-engineering applications.

[Source(s): American Association for the Advancement of Science, Science Daily]