How the mouse with human ears changed the world?

Twenty years ago, a mouse with a human ear on its body caused waves of anger and criticism, but the reality later proved the value of this experiment.

During the 20th century, mankind witnessed great advances in the field of science. It is known that, as technology advances, medicine will advance to the point where every part of the human body will be grown externally and implanted like the replacement of parts of a broken machine. . Although these scientific theories have been debated for decades, no one is rational enough to wait for it to happen.

The peculiarity of the ear

Plastic surgery has developed very rapidly at the end of the 20th century, but in the human body, the ear is still the most difficult part to regenerate, because it is made of cartilage. Although cartilage can be made, it is difficult to make from human tissue. As a result, many people who have had an ear-related accident will have to live with an abnormally shaped ear or be permanently absent.

In the late 1990s, doctors Charles Vacanti, Joseph Vacanti and Bob Langer wanted to create human organs in the laboratory. They experimented with creating "biodegradable scaffolds" or structures that could dissolve inside a body. One day, Joseph Vacanti heard his colleague complain that it was difficult to create new ears for patients who lacked ears, because the ears had odd and complex shapes.

Picture 1 of How the mouse with human ears changed the world?
World medicine has made great achievements in creating and 'implanting' organs into living bodies.

That irony fact prompted the birth of the 'mouse-ear' project in the 1990s, led by Charles Vacanti, an expert in stem cell and tissue engineering. In the same year, Charles Vacanti, with the help of his brother Joseph Vacanti (tissue regeneration expert), attempted to grow a small piece of human cartilage on a biodegradable scaffold.

The scientists decided to make a scaffold shaped like a human ear and put cartilage cells from a cow on it (cartilage is a semi-rigid tissue found in the human ear, nose and chest). The scientists then selected a line of mice that was immunocompromised, meaning its immune system did not reject foreign bovine cells. They anesthetized the mouse, made an incision, and placed an ear shape under its skin. As expected, the body of the mouse feeds on bovine cartilage cells and when the scaffolding dissolves, the mouse is left with the shape of an artificial ear, without an eardrum.

The world was amazed when all the major news agencies shared a picture of a mouse - known as 'Vacanti mouse' - Vacanti mouse, 'earmouse', or 'ear-mouse' - wearing a human ear . Some expressed great excitement, most expressed fear, others expressed outrage, attributing the ethical aspects of such experiments.

A movement against genetic engineering exploded in the Western world due to the misunderstanding that the experiment involved genetic engineering, that the DNA of the rat had been genetically engineered to create human ears on its back. The misinformation is also due to some news agencies using such keywords to advertise the photo, not knowing that the actual testing began nearly 10 years before the photo was available, and without genetic engineering. which were used in this experiment.

In fact, the truss frame is made from a synthetic material polyglycolic acid, which is commonly used in plastic surgery. The fibers of this material are molded into a loose mesh membrane in the shape of an ear with 97% air, which leaves plenty of space for the cells to fill. This material will dissolve into carbon dioxide and water as tissue begins to grow in the affected area.

If doctors perfect the technique in mice and then in large animals, maybe one day they will help humans grow missing body parts. It sounds simple, but the process takes about 8 years until it is ready to be introduced into an organism to develop. Attachment to human tissue would not be effective because it would not regenerate quickly enough before the original cartilage had dissipated. Another problem is that all immune systems in all organisms will identify this cartilage as a foreign body and will attempt to eliminate it.

Special mouse

The rat used for this experiment is called a 'naked mouse' because of its lack of hair. A random mutation the species has acquired leaves them hairless and immune system. The coat doesn't make much of a difference, but the lack of an immune system is what makes this rat so special and perfect for the experiment. Without an immune system to fight off the foreign body, the cast cartilage can be filled with cells until it has fully grown into the ear.

There are no special requirements for human cells, as long as the cells are healthy and growing fast enough. Synthetic ear cushions are created to recreate the ear of a 3-year-old child. This ear after the transplant will grow again as the child grows up. Synthetic ear cartilage was surgically placed on the back of the mouse and kept there for 12 weeks until the scaffold was filled with living cells.

This artificial ear is up to 90% similar to the natural human ear, which is very surprising since the experiment did not involve any genetic engineering with human DNA. The ear was then successfully implanted in a child.

Despite the misunderstandings, success has demonstrated the capabilities of medicine and science in general. People understand that the future will surpass sci-fi movies. The Vacanti mouse is not simply an exercise to help scientists understand how to develop human organs, using skin cells and cartilage.

In January 2018, doctors in China and Japan published a study: In 2015, they recruited children with a deformed ear. The scientists scanned their normal ears, inverted their shape using a computer, and 3D printed a biodegradable scaffold. They then added cartilage cells from the patient and placed the scaffolds under the skin. As a result, cases of malformations in one ear now have two almost normal ears.

Without the experimental rat-ear, medical advances of this kind might not have occurred. Today, the 'implantation' of the human ear has been successful, what awaits us in 20 years and beyond?