Talking About Re-Generation

September 16, 2009 – The human body is a miraculous machine, but there are many injuries and diseases it cannot heal on its own. Dr. Molly Shoichet, an NSERC-funded researcher at the University of Toronto, is making incredible headway in the field of regenerative medicine that may one day lead to effective treatments for serious injuries like paralysis.

The current “gold standard” treatment, grafting tissue from another part of the body for transplant, in effect, creates a second injury to treat the first. However, once a transplant is in place there are several problems that can prevent its success. If there are insufficient nerve cells, or the cells do not grow in the desired region, the transplant will fail. In the case of spine and brain injuries, the transplantation itself can cause additional trauma and must overcome the inhibitory environment in the scar-like tissue around the injury to achieve regeneration.

Since nerve transplants present so many issues, Dr. Shoichet has decided to tackle the problem another way: encouraging nerve re-growth in the injury.

Dr. Shoichet and her team have created scaffolds that guide nerve regeneration. Using a process she developed, Dr. Shoichet designs polymers to make porous, tissue-like hydrogels that provide support for the new nerve cells. A laser blazes the gel to implement 3-D patterns laced with peptides and molecules that encourage nerve re-growth. These stimulants determine how the cells grow and differentiate. Dr. Shoichet describes them as “breadcrumbs” for the nerves to follow as they regenerate. Over time, the biodegradable hydrogel dissolves and leaves only the regenerated tissue in its place.

Regenerative medicine could very well change the way people are treated for traumatic injuries, ranging from broken bones to severed spinal cords and beyond. Faster healing periods and restored functionality are just some of the benefits it could provide. Dr. Shoichet is also working on a localized drug delivery technique whereby a fast-setting polymer solution is injected at the site of injury—a spinal cord break, for example—where it quickly gels to deliver the drugs directly to the injured tissue.

Though there is still a lot of work to do, Dr. Shoichet’s novel strategies have shown promising results. She and a co-researcher are engineering a minimally-invasive delivery strategy to stimulate stem cells in the brain after a stroke. In preclinical trials for spinal cord injury treatment, paraplegic rats showed nerve tissue regeneration and some restored movement when the scaffolding was implanted. More recently, Dr. Shoichet and her team have applied their technique to design an artificial retina for transplantation to patients who have suffered vision loss.

The future of Dr. Shiochet’s research holds the promise of making a positive difference in the lives of injured Canadians.