Researchers have developed a new method of repairing bone using a synthetic bone graft substitute material. Combined with gene therapy, they say it can mimic real bone tissue and has potential to regenerate bone in patients who have lost large areas of bone from disease or trauma.

The researchers have developed a scaffold material made from collagen and nano-sized particles of hydroxyapatite which acts as a frame for the body’s own cells and repairs bone in the damaged area using gene therapy. The cells are tricked into overproducing bone producing BMPs (proteins), encouraging regrowth of healthy bone tissue. 

Professor Fergal O’Brien, Principal Investigator on the project at the Royal College of Surgeons in Ireland (RCSI) says, “Previously, synthetic bone grafts had proven successful in promoting new bone growth by infusing the scaffold material with bone producing proteins. These proteins are already clinically approved for bone repair in humans but concerns exist that the high doses of protein required in clinical treatments may potentially have negative side effects for the patient such as increasing the risk of cancer. Other existing gene therapies use viral methods which also carry risks.” 

Bone grafts are second only to blood transfusions on the list of transplanted materials worldwide with approximately 2.2 million procedures performed annually (1) at an estimated cost of $2.5 billion per year (2). The majority of these procedures involve either transplanting bone from another part of the patient’s own body (autograft) or from a donor (allograft). However, these procedures have a number of risks such as infections or the bone not growing properly at the area of transplantation. There is a large potential market for bone graft substitute materials such as these scaffolds. 

“By stimulating the body to produce the bone-producing protein itself, using non-viral methods these negative side effects can be avoided and bone tissue growth is promoted efficiently and safely,” said O’Brien.

While the biomaterials developed in this project were for bone repair and as an alternative to existing bone graft treatments, they say the gene delivery platform may also have significant potential in the regeneration of other degenerated or diseased tissues in the body when combined with different therapeutic genes. Their Tissue Engineering Research Group wants to use the platform to deliver genes that promote the formation of blood vessels (using angiogenic genes) in the regeneration of tissues which suffer from compromised blood supply such as heart wall tissue which has been damaged following a heart attack. 

Citation: Curtin, CM, Cunniffe, GM, Lyons, FG, Bessho, K, Dickson, GR, Duffy, GP, O’Brien, FJ. Innovative Collagen Nano-Hydroxyapatite Scaffolds Offer a Highly Efficient Non-Viral Gene Delivery Platform for Stem Cell-Mediated Bone Formation. Advanced Materials 01/2012; 24(6):749-54.

NOTES:

(1) Lewandrowski KU, Gresser JD, Wise DL, Trantol DJ. Bioresorbable bone graft substitutes of different osteoconductivities: a histologic evaluation of osteointegration of poly(propylene glycol-co-fumaric acid)-based cement implants in rats. Biomaterials 2000; 21:757-764.

(2) Desai BM (2007) Osteobiologics. Am J Orthop (Belle Mead NJ) 2007; 36:8-11.