- Regeneration in animals is the restoration of tissue or limbs.
- African spiny mice likely have an inactive gene; this permits skin regrowth.
- Wound healing in humans may later advance from scarring to thorough tissue regeneration.
The Marvel comic book hero Deadpool can regrow skin, tissue, and even limbs after fierce battles. This type of incredible healing ability is called regeneration. Regeneration can be found in salamanders and marine invertebrates. Some species of starfish can even regrow an entire body from an arm. Although regeneration has long been regarded as very limited in mammals, the study of African spiny mice (Acomys) in bioresearch provides us a means to better understand this exceptional ability.
Two species of African spiny mice (Acomys kempi and Acomys percivali) inhabit parts of Uganda, Kenya, and Somalia. Their skin is 77 times more fragile than that of the typical lab mouse. Acomys use this trait to escape from predators. Because their skin tears so easily, the mice are able to get away from gripping jaws or claws.
Perhaps in response to having weak skin, Acomys can also regrow lost skin. Whereas most mammals generate scars to close wounds, when Acomys are injured, they completely recover every layer of skin. Unlike spiny mice, human wounds form scars when healing. Scarring can be unappealing and the tissue is more rigid than the surrounding skin. If our regeneration ability could be enhanced, our wounds would be covered with new layers of skin rather than scars. This would restore the skin’s overall strength, appearance, and flexibility.
Dr. Ashley W. Seifert, an associate professor at the University of Kentucky, compares regeneration and scarring: “Regeneration seems to be an all or nothing trait. I definitely think of them as two extremes on a spectrum. It’s really rare to find an animal that ‘kind of’ regenerates.” For example, Dr. Seifert explains that it’s impossible to find a salamander that regrows only half a limb.
Dr. Seifert and his colleagues were the first researchers to publish a paper on the incredible regenerative ability of spiny mice. While assisting another scientist conducting field research in Kenya, Dr. Seifert learned that Acomys’ tails and skin tear off easily. The observation opened up a new chapter of regeneration research. Dr. Seifert has since published many more papers on regeneration in spiny mice and helped set up Acomys colonies (groups of animals for experimental purposes) in laboratories around the world.
Dr. Seifert believes that Acomys’ healing traits occur because they may not activate certain genes that prevent regeneration. “Acomys are missing something important, and that’s what we are looking for,” says Dr. Seifert. A group of scientists from the Wistar Institute in Philadelphia published a paper in 2010. It showed that if a lab mouse has an inactive p21 gene, the healing process can go so far that natural openings, such as earholes, heal over completely.
To regenerate tissue, certain cells called fibroblasts are required. These form a matrix or scaffolding for new cells to grow on. They also require help from another cell type, called macrophages. These cells eat up the damaged tissue. Dr. Seifert and his team are looking more deeply into fibroblasts, which they believe are the key to regeneration.
It will likely take several years for studies of African spiny mice to generate therapies that improve human wound recovery. Nonetheless, thanks to our rodent friends, someday in the future, Deadpool’s extraordinary healing ability may become a reality.
Dr. Ashley Seifert is an associate professor at the University of Kentucky, USA. He received his bachelor’s degree at Bowdoin College, and his M.Sc. and Ph.D. at the University of Florida. He published the first paper on Acomys and their tissue regeneration ability in 2010. Currently, he and his lab, the Seifert Laboratory for Animal Regeneration and Development, are investigating the key to tissue regeneration in mammals.
- Haughton, Cheryl L., et al. “The Biology and Husbandry of the African Spiny Mouse (Acomys cahirinus) and the Research Uses of a Laboratory Colony.” US National Library of Medicine, Jan. 2016, www.ncbi.nlm.nih.gov/pmc/articles/PMC4747004/.
- Bedelbaeva, Khamilia, et al. “Lack of p21 expression links cell cycle control and appendage regeneration in mice.” US National Library of Medicine, 30 Mar. 2010, www.ncbi.nlm.nih.gov/pmc/articles/PMC2851923/.
- Seifert, Ashley W., et al. “Skin shedding and tissue regeneration in African spiny mice (Acomys).” U.S. National Library of Medicine, 27 Mar. 2013, www.ncbi.nlm.nih.gov/pmc/articles/PMC3480082/.
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This article was written by Chieh Hsu. Chieh and the cSw student editing team would like to thank Alisa Zapp Machalek for serving as mentor on this story. Alisa is a Senior Science Writer at the National Institute of General Medical Sciences within the National Institutes of Health.
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