You've all probably heard about the latest advance in tissue engineering:
The researchers removed all the cells from a dead rat heart, leaving the valves and outer structure as scaffolding for new heart cells injected from newborn rats. Within two weeks, the cells formed a new beating heart that conducted electrical impulses and pumped a small amount of blood.
With modifications, scientists should be able to grow a human heart by taking stem cells from a patient’s bone marrow and placing them in a cadaver heart that has been prepared as a scaffold, Dr. Taylor said in a telephone interview from her laboratory in Minneapolis. The early success "opens the door to this notion that you can make any organ: kidney, liver, lung, pancreas - you name it and we hope we can make it," she said.
Todd N. McAllister of Cytograft Tissue Engineering in Novato, Calif., said, "Doris Taylor’s work is one of those maddeningly simple ideas that you knock yourself on the head, saying, ‘Why didn’t I think of that?’ "
Very clever - and simple, obvious in hindsight, as all the truly clever ideas are. It's a measure of the investment made in regenerative medicine and tissue engineering in the past decade that research groups are beginning to find very promising paths around the complexities involved in growing replacement organs from scratch.
One such complexity is the placement of cells; if you don't happen to have a complete guide to where cells must go, and a map of chemical signals released in various regions of the growing organ, you must perform all that work yourself. How else to guide the cells to form the right sort of tissue in the right place? Blood vessels in particular are a thorny, crucial problem.
Personally, I anticipate much of the work of the next decade will go towards developing the knowledge, techniques, industry and infrastructure to mass produce nanoscale-featured, tailored, biochemical-laced scaffolds for the regrowth of entire organs, ready to be seeded with stem cells. That will still be the course, I've no doubt - but a model to hand in the form of an existing organ turned into such a scaffold will speed the work.