One in 20 people will need some kind of tissue transplant in their lifetime, and increasingly surgeons are turning to animals for help.
This is no ordinary lab mouse.
“Ideally, it would be indistinguishable from a normal ear," said Dr. Joseph Vacanti, Chief of Pediatric Surgery, Massachusetts General Hospital for Children.
Vacanti's lab is on the cutting edge of regenerative medicine.
"We actually used human cartilage cells in a human ear shape and then on the back of this mouse,” said Vacanti. “The human cartilage cells grew into a human ear."
He plans to re-grow an ear on a human in a similar way.
"We can give somebody back their own face, that's been either ravaged by cancer or destroyed by a terrible accident or injured by war," said Vacanti.
Pigs are primary source of tissue.
"Believe it or not, their genetic makeup is pretty close to humans," said Dr. Samer Mattar, bariatric surgeon, Clarian Bariatrics.
Surgeons use material made from the pig's small intestines to repair torn muscles caused by hernias. A powdery substance, made from a pig's bladder, helped a man's finger go from this to this.
"The simplest applications involve just being able to spread a powder or a particular form of the powder on the wound site so it can affect the wound healing process," said Dr. Steve Badylak, DVM, Director of McGowan Institute for Regenerative Medicine in Pittsburgh, PA.
Fish are helping scientists fix hearing disorders. If these zebra fish lose hearing, they naturally re-grow new auditory cells. Scientists are studying the genetic process to restore hearing in humans.
"So our hope is that we can actually end deafness," said Dr. James Hudspeth, Howard Hughes Medical Institute.
According to research in the journal Transplantation, transplants from pigs might actually be safer than transplants from humans. Pig skin and pig valves have been used in human transplants, but not entire organs.