Behind the picture: The sponge that turns cells into bone-fixing factories
The first UK Regenerative Medicine Conference took place in London this week. Professor Fergal O’Brien, who heads the Tissue Engineering Research Group at the Royal College of Surgeons of Ireland, tells us about his work to help the body to fix itself.
Although our bodies have an amazing capacity to repair themselves, some damage is too big or too difficult for us to fix.
Fergal’s team have found a way to boost that capacity by developing a sponge-like implant that reprograms our cells to supercharge the healing process.
“Traditionally, implants were made of materials that don’t interact with the cells in our bodies. They were inert and designed not to cause problems, so our immune system would accept them and not attack them,” explains Fergal.
“But now we are increasingly looking at ‘bioactive biomaterials’. What we mean by that is the implants actually interact with the body, creating a controlled response that helps organs and tissues to recover and regenerate.”
Fergal’s team’s sponge-like biomaterials are called ‘scaffolds’. The scaffold is made from a protein famously used in cosmetic surgery: collagen. Collagen is a structural protein giving strength and flexibility to human tissue and can be found in nearly every human organ.
“The benefit of the sponge-like structure is that it’s porous. That means cells can move into it. It also makes it easier for blood vessels to grow through the gaps – a major challenge in tissue engineering.”
Genes and nanoparticles
Before inserting the scaffold into the body, it is filled with tiny capsules called ‘nanoparticles’ containing genes with all the information needed for repair.
Once the scaffold is in place, cells naturally start to form a network within the structure and, as they do so, they ingest the nanoparticles. The genes attached to the nanoparticles direct the cells to produce lots of the specific proteins needed for the body to heal.
“Our most successful example so far”, Fergal tells us, “has been to use this technique for bone repair: the genes enter the cell and the cell starts to produce far more proteins for bone repair than it normally would.”
This scaffold could be used to treat cases such as bone fractures that won’t heal or major holes in the bone left behind after a tumour has been removed.
Fergal’s team spends a great deal of time testing different doses of the nanoparticles to find the perfect balance. “A huge concern for us is safety. As we’re getting the body to create more of a protein than it normally would, we need to ensure that we can control that process.
“What’s great about this type of therapy is we can decide how many nanoparticles to insert and ensure that the number reduces over time so that the effect wears off when it’s no longer needed.
“Other methods of delivering genes, such as by adapting a virus, change the genome itself meaning that it can be more difficult to predict every effect.”
“Regenerative medicine is an incredibly interdisciplinary field – you need polymer chemists, bioengineers, life scientists from all fields, biochemists, gene delivery specialists and, critically, clinicians. Without clinicians giving a practical perspective, nothing is ever going to make it to through to the clinic and help patients.
“I think that’s one of the great things the UK has done – it’s brought together these groups with different skills working on common aims.”
And that is the aim of this week’s conference organised by the UK Regenerative Medicine Platform (UKRMP). The platform has a number of interdisciplinary research ‘Hubs’ that bring together experts to help address the main challenges of getting regenerative medicine into the clinic. Fergal describes the conference attendance list as “a who’s who of the regenerative medicine field over in the UK.”
“The UKRMP hubs and conferences like this are essential because you can’t work in isolation in this field. You can’t be an expert in absolutely everything. The hubs in the UK are bringing together the top people in different disciplines with a common aim. They all want to develop technologies that benefit patients and society. Bringing them together provides a major opportunity for breakthroughs.”