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The super-healing power of lizards

Leopard geckosImagine a flawless stretch of skin, regenerated without a trace of trauma only weeks after a scarring incident such as a deep cut. It’s not science fiction – lizards like the leopard gecko are able to rapidly heal their skin scar-free and even re-grow a new tail within a matter of weeks.

In the not-too-distant future, could mammals like humans also employ this method of healing?

Noeline Subramaniam, who recently completed her Master’s degree, has been researching the biology of scar-free wound healing under Dr. Matthew Vickaryous’ supervision, in a graduate lab that aims to understand why some organs, tissues and species are able to regenerate whereas others cannot. The lab, located in the Department of Biomedical Sciences at the University of Guelph’s Ontario Veterinary College uses leopard geckos as their research model.

The focus of Subramaniam’s research is comparing the roles of growth factors present in scar formation (adult mammals) and scar-free wound healing (exe. zebrafish, axolotls) before, during and after the healing process. Interestingly, these same growth factors that are present in scar-free wound healing are present in scar formation. The two types of healing go through very similar molecular processes using the same growth factors, but differ in terms of when these factors first appear, how long they are expressed and the end result.

“Everyone scars, everyone gets minor scrapes and stuff,” says Subramaniam. “But if you get severe injuries like third-degree burn victims and diabetic patients who have a hard time healing – these are the sort of patients that we’re trying to help down the line.”

Using biochemical markers, Subramaniam tracked the progress of skin regeneration in leopard geckos, noting the levels of VEGF (vascular endothelial growth factor) present in the dermis and epidermis of the skin during the different stages of healing. The growth factor plays a major role in stimulating blood vessel formation and is found in modest quantities during scar-free wound healing. In comparison, there is much more VEGF and therefore, vascularization, during the process of scar formation.

Because of its adaptability, ability to naturally regenerate the tail and ease of obtaining captive-bred (not wild caught) specimens, the leopard gecko is an ideal model for organ regeneration. When a leopard gecko is completely healed from a wound, the site of injury can’t even be differentiated from regular skin at a cellular level. In contrast to humans and other mammals, scars that form can take up to a year to remodel, but will never entirely disappear – and that can cause life-long discomfort or reduced flexibility especially near joints.

Subramaniam hopes that the research she has begun in the Vickaryous lab will continue on after she leaves. Her future goal for this project is to determine if changes in the ability of the skin to create blood vessels following an injury prevents scar formation in leopard geckos.

Moving forward, Subramaniam is trying to understand the mechanisms that differentiate scar formation from scar-free wound healing. By connecting knowledge in the area of regeneration (gained from the study of lizards), Subramaniam wants to contribute to the development of scar-free wound healing therapies in mammals.

This research was funded by an OVC (Ontario Veterinary College) scholarship. The Vickaryous lab is funded by the Natural Sciences and Engineering Research Council of Canada (NSERC).

Subramaniam’s Master’s degree project was co-advised by Prof. Matt Vickaryous and Prof. Jim Petrik of the Department of Biomedical Sciences in a long-standing collaboration between their respective labs.

You can follow their updates on research in their lab on Twitter, at @moe_science and @VickaryousLab.

Article by Karen K. Tran

(Photos courtesy of Vickaryous Lab and Karen Tran)