Innovation

How Using The Antifreeze Proteins Of Ticks May Protect Us From The Cold

cold
When we get too cold, we suffer the risk of frostbite or hypothermia — but what if humans could borrow the antifreeze properties of certain organisms living in extreme cold? Photo courtesy of Shutterstock">Shutterstock

When there's a temperature change in the environment, the human body internally adjusts; we shiver or sweat to warm up or cool down, respectively. Sometimes, we turn to coats and scarves for help. But humans may soon borrow certain “antifreeze” qualities from reptiles and insects in order to better protect themselves when the temperature drops, according to a new study published in PLOS ONE.

The study aimed to analyze how certain species among plants, fish, insects, amphibians, and reptiles use antifreeze proteins to create “cold hardiness” during the winter. These species are examples of ectotherms, or organisms that aren’t capable of moderating their own body temperatures. Instead, they rely on external heat sources to stay warm. Both ticks and fish have antifreeze proteins that protect them from getting frozen tissues during winter months.

Ticks in particular are Erol Fikrig's, a professor of medicine at Yale and the lead author of the new study, main focus. They have a protein called IAFGP that is triggered during winter months, which protects them from the cold. Fikrig and his team bred special mice that contained the spliced genes responsible for antifreeze properties in ticks in order to see if mammals could derive similar protection from these proteins — especially since human's internal methods of temperature regulation (like body insulation and blood flow) only go so far.

Through skin sample tests, where the researchers placed skin cells in slightly above freezing temperatures for days, as well as tests on living mice (where their tails were placed in a cooling solution for 7 days), the team were able to test their bodies against cold. They found that the mice who contained the IAFGP protein showed higher resistance to frostbite; 60 percent of them had no frostbite on their tails compared to only 11 percent of the mice without IAFGP.

“Antifreeze proteins (AFPs) contribute to cold hardiness by reducing cold-induced damage in a non-colligative manner, binding directly to the surface of ice crystals,” the authors explained. “This interaction inhibits the addition of water molecules to the developing ice lattice and impedes crystal growth. In turn, this prevents the formation of sharp ice needles that inflict tissue damage.” In other words, these natural antifreeze proteins prevent ice from taking over the organisms’ tissues during severe cold — and it’s these qualities that allow such living things to persist in “extreme niches” of the earth, like arctic waters or glaciers.

But this is just a preliminary study, and it will be quite a while before researchers can even begin to test this in humans — mainly because they can’t use the same method they used to inject the proteins into the mice. “Our study doesn’t address the question of how we’d deliver the protein,” Fikrig told The Washington Post. “We’re using transgenic mice, and we’re obviously not going to put this gene into people.”

In the meantime, as winter rasps out its last icy dying breaths, bundle up.

Source: Heisig M, Mattessich S, Rembisz A, Acar A, Shapiro M, Booth C. “Frostbite Protection in Mice Expressing an Antifreeze Glycoprotein.” PLOS One, 2015.

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