REPLACING CONVENTIONAL BONE REPLACEMENTS
Organ, tissue, and bone transplants may have proved revolutionary, but they’ve always come with the risk of rejection. Whether dealing with organic tissue or metals, the patient must take immunosuppressant drugs to prevent infections.
Regenerative medicine — which combines life, material and medical science — is working toward solutions that would reduce these risks, and the best way to do that is to replace what you’ve lost with what you’ve already got.
In Concordia’s faculty of engineering and computer science, postdoctoral fellow Ehsan Rezabeigi has developed a synthetic bone graft, or scaffold, that’s not only compatible with the body, it also promotes bone regrowth, and dissolves over time. It’s so groundbreaking that his research has already won him several awards.
Still, Rezabeigi humbly points out that he’s just building on Dr. Larry Hench’s work with bio-active materials, which the latter developed during the Vietnam War to help regenerate bones in soldiers that had severe bone loss or damage.
“It’s not like many years ago, where scientists would create phenomenal things more often,” Rezabeigi said. “Right now, we’re adding another piece to the puzzle. Because bones are complex, it’s difficult to mimic that structure. So everyone is trying to produce something to obtain the ideal scaffold for bone regeneration.
With its FDA-approved, highly porous polymer base, Rezabeigi’s scaffold imitates the makeup of bones. Its 90 per cent porosity serves to make it light — in sharp contrast to metal implants — and to make room for bone regrowth and blood vessel circulation, which feeds the young bone cells.
Combined with the polymer base is a synthetic bioglass composition that’s so effective, other scientists are also studying it to find ways of preventing tissue loss. In Rezabeigi’s case, it’s used to stimulate bone regeneration.
“(The bioglass composition) makes the number of bone cells increase, which is what makes the bones grow,” he explained, adding, “It’s bioresorbable, so it can dissolve safely in the body.”
That the body absorbs the scaffold isn’t just significant because it means the risks of infection and rejection are virtually gone, it also eliminates the need for surgery to remove the implant. In the end, patients have their own bone, instead of a heavy metal alternative that sets off detectors.
For aging populations, this is a crucial development. Rezabeigi’s scaffold could be used to treat broken bones and any other type of bone damage more effectively. It would also minimize surgeries for those who aren’t ideal candidates for intrusive procedures.
To make his scaffold more suitable for seniors, Rezabeigi is working to perfect his formula.
“Bone regrowth depends on a person’s age and gender,” he said. “For the elderly, the bone regrowth rate is slower than that of a younger person. So we need to create scaffolds with different reconstruction and absorption rates.”
That said, the preliminary results of Rezabeigi’s continued in-vitro testing are promising. Within a few days, he and his team noted the formation of hydroxyapatite, or bone mineral. What this suggests is that the bone could regenerate in a shorter amount of time than expected.
Despite these outcomes, Rezabeigi knows it will be at least a few years before his scaffold goes to clinical trial. That gives him time to work on making his scaffold as sturdy as metal, which could diversify its use, in addition to helping doctors deal with major bone loss.
“We’d like for the scaffold to be used in all parts of the skeleton, but it’s tricky because the rate of bone regeneration, as well as the pressure applied, is different for each body part,” he said. “But that’s certainly the goal: to be able to use the scaffold anywhere.”
Read more at concordia.ca/encs