Bone grafts, though imperfect, are used to repair fractures so severe the bone cannot mend the breach on its own. A Cedars-Sinai-led team has developed a combination treatment using ultrasound, stem cells and gene therapy that could replace this method.

Bone grafted either from the patient, usually from the hipor from a donor, is designed to actas a scaffold for the broken bone to heal and to be reabsorbed over time. But both types of grafts can cause problems. Some patients do not have enough healthy bone for a graft. In other cases, taking bone from the hip can lead to new injuries or infection. And donor grafts may not integrate properly into the bone,failing to fix the break.

The Cedars-Sinai investigators, led by Dan Gazit, injected a collagen matrix into the fractured leg bones of lab animals, according to a statement. Over two weeks, this matrix recruited stem cells from the fractured leg. Then, to kickstart healing, the team used an ultrasound pulse and microbubbles to deliver a bone-inducing gene. Eight weeks later, the fracture was healed in all animals that underwent the treatment. (See video below.)

Were combining an engineering approach with a biological approach to advance regenerative engineering, which we believe is the future of medicine, Gazit said.

Related: Medtronic defends handling of Infuse bone graft study to probing lawmakers

It is difficult to pin down exact numbers for bone graft procedures, but the team said more than 2 million procedures are performed around the world annually. Grand View Research valued the bone graft market at $2.3 billion in 2015 and projected it willgrow beyond $3.6 billion by 2024.

This study is the first to demonstrate that ultrasound-mediated gene delivery to an animals own stem cells can effectively be used to treat nonhealing bone fractures, said Gadi Pelled, an assistant professor of surgery at Cedars-Sinai, in the statement. It addresses a major orthopedic unmet need and offers new possibilities for clinical translation.

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Gene therapy and stem cells prompt bone to regrow itself - FierceBiotech