What ever happened to the mouse with a ear on it’s back?


You may remember seeing this picture years ago on TV or in an article – the mouse with a human ear on it’s back.

You may have thought it was a genetically engineered mouse, strangely deformed, or the result of mad scientists “playing God”.

20 years ago, brothers Joseph and Charles Vacanti, who were both Harvard surgeons, alongside MIT engineer Bob Langer, experimented with various techniques to create human body parts in the lab.

In their attempts to understand how to help grow body parts for humans they implanted the shape of a human ear in the back of a mouse. Their results were published in 1997 and a documentary on tissue engineering aired on the BBC, showing the world the bizarre animal, The Vacanti Mouse.

The mouse is still considered by many to be an icon of the power of science.

Joseph Vacanti was interviewed by Newsweek, 20 years after experiments, to hear what he had to say about it all in hindsight.

In the interview Vacanti explains how he worked as pediatric surgeon and was trying to address the organ shortage. He figured:

“Well why don’t we do what humans do when we need something—we design it and we make it.”

His friend who was a pediatric plastic surgeon told him that the most difficult problem they have when it comes to reconstructive plastic surgeon in children is the ears – they could never construct good ears.

Vacanti and his team were making cartilage and could make it in different shapes so they developed a way to make a scaffolding in the shape of a human ear. The scaffolding was bioabsorbable and biocompatible so it disappears over time. It is seeded with cartilage cells and then put in an incubator. Then, when ready, the now-living structure is removed from the incubator and implanted in an animal.

He thought that the visual impact of a mouse with an ear on it’s back would be too controversial for the public to see, so he wanted to keep it under wraps. But the BBC were doing a documentary on tissue engineering and the Vacanti brothers along with Langer agreed to be interviewed.

All went as planned until they interviewed his brother Charles:

“When they went to my brother’s lab at the University of Massachusetts, he showed them everything he was doing, and said “I’ve got this really cool thing to show you,” which was the mouse with the ear on its back.”

The BBC trailers for the documentary then included the iconic shot of the interviewer with the mouse, and it wasn’t too long then before people started to become intrigued with the image.

Vacanti said that the mouse was not harmed by their work, and it lived ‘happily ever after’ once the ear was removed. He also said he would prefer not to have to use animals for these experiments:

“In the world of medicine, there’s a massive controversy about the use of animals. We’re hoping to eliminate the need to use animals because we can now generate human structures and tissues using human cells and we can study them without the use of animals. That’s our long-term goal.”

Vacanti believes that the mouse played an important role in the ongoing quest to produce enough human organs for the massive number of people that require replacements. He added:

“I would estimate that well over a billion people on planet earth need new organs. Most of the people in Asia who have advancing liver disease from infection and cirrhosis are going to die from it.

Not only do we need to have these organs available, but also we need to manufacture them like cell phones. That’s the dream, that’s what originally motivated us with this mouse.”