At Queen’s University, engineering professor Brian Amsden is working on polymer scaffolds that let patients grow new cartilage (for knees and hips) and anterior cruciate ligaments (ACLs), which are often damaged in sports.

His ACL project will involve biologists, surgeons, a stem cell expert, physiologists, materials researchers and engineers, all involved in turning fat stem cells (the most available kind) into tough, strong ligaments, “because the knowledge that is required is huge.”

And a ligament is really just the body’s equivalent of a rope, he says.

“We’re talking about fairly simple tissues, and yet we have a hard time regenerating those. If you’re looking at the liver, which is a very complicated tissue and a vast number of different types of cells, a lot of blood supply, a lot of nerve supply,” that’s harder than a ligament with few cells types and not much blood supply.

The kidney is sophisticated machine that balances the body’s chemistry. The heart looks like simple muscle, but it has a complex set of nerves that keep it beating at the right pace.

“Trying to regenerate something like that is going to be far more difficult,” Amsden says.

But will it happen some day?

“Well yeah, I think it’s possible.” But it won’t happen soon, or easily. “What is really lacking is an understanding of the biology. You’re trying to recreate what happens in an embryo, but you’re doing that in an adult.