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CanaryActive5296 t1_is1amk1 wrote

Reply to comment by Fogl3 in Why can we freeze embryos for IVF but not adult humans? What makes it possible for embryos? by Nimynn

There are multiple types cryoprotectants and while they are generally supposed to be non-toxic it is only to a certain extent of concentration and exposure time. Extended exposure will interfere with daily bodily functions and metabolism. So unfortunately impossible to walk around with it indefinitely. The wolverine question is interesting because some animals have evolved to have cryoprotectants for living in the arctic or surviving winters! I don't know of any mammal that can do it but I know of at least 1 frog and 1 fish species. Info may not be updated but last I checked both are being studied to study how to preserve human organs!

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regular_modern_girl t1_is2rpvn wrote

The only vertebrates I know of that can survive freezing completely solid are ectotherms, and I’ve also never heard of any bird or mammal species being able to withstand it, so it might just be that organisms that have evolved to operate with a constant core temperature aren’t able to survive the extreme cold leading up to freezing, even besides the problem of ice crystals damaging cells? But I don’t know, that’s mostly just a guess and it may just be coincidental that no endotherms have evolved this ability.

Interestingly, there has been some evidence to suggest that critically-injured trauma patients can sometimes be kept just barely alive long enough to be saved by being cooled down to very low temperatures in a controlled setting, as I guess this basically slows down a lot of physiological processes in such a way that essentially buys doctors time to do what they need to. The procedure is called EPR, or Emergency Preservation and Resuscitation, and is still experimental, and it’s obviously still a far cry from complete freezing, but it is something.

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sbeezee t1_is6fyaw wrote

There is some evidence that spruce at Arctic treeline increase simple sugars in needle tissue in late fall as a cryoprotectant. Do you know of any other species that use simple sugars (glucose, fructose, sucrose) as cryoprotectant?

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