What Can We Learn From Salamanders?

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Did you know that more than 2 million people in the United States suffer from the loss of a limb?

You have probably seen or heard of prosthetics, but imagine what it would be like if those people were able to simply regrow their lost limbs.

Although scientists have not quite figured out how to regenerate human limbs and other body parts, they are developing an understanding of this field by studying salamanders. 

Why are Axolotls unique?

There are many animals that are able to regenerate certain body parts at certain parts of their lifetimes, including tadpoles, starfish, and flatworms. Of course, no mammals have the capacity to regenerate limbs, though there have been cases in which humans have been able to regenerate fingertips.

However, Axolotls are unique in that they can regenerate their limbs, tail, heart, lungs, eyes, spinal cord, and parts of their brain throughout their entire lifetime!

How do they do it?

When an Axolotl loses a limb, blood cells around the injury site rapidly clot (stick together) to stop the bleeding. Then, a layer of cells forms a wound epidermis or outer covering of cells that acts as a barrier to keep out infection. The cells of the wound epidermis begin to divide into bone, cartilage, or muscle. Eventually, the structure flattens into a perfect replica of the lost body part.

You may be wondering why our bodies do not follow the same process. Scientists hypothesize that certain parts of our immune system causes us to form scar tissue upon cell division at an injury site rather than re-growing the previous structure. If we were to remove these parts of our immune system, our body would no longer be able to fight off infection and disease in order to keep us healthy.

What can we learn from the Axolotl?

Although there are certain aspects of the Axolotl’s healing process that we cannot imitate, scientists are trying to sequence the genome of the Axolotl to determine which genes play a role in tissue regeneration.

A genome is a collection of genes that encode proteins to perform certain functions in the body. For example, in your genome, you have a gene that encodes the level of melanin to be produced in the cells in your hair. Melanin is a protein that gives your hair and skin color. Scientists are hoping that if they can identify the gene responsible for the Axolotl’s healing process that they will be able to imitate the process in humans. Wouldn't that be something!

Sources: Harvard.edu, Gizmodo, amputee-coalition.org