argentnoelle

A Meta on the probability of the above. Also: weird science facts.

(this has a lot of summaries from scientific articles, and those things are complicated, so it’s possible there may be slight mistranslations in the process. See sources for most accurate information)

•UNSURPRISINGLY, PEOPLE CAN’T SURVIVE BEING FROZEN SOLID …

This article (1) speculates on how the whole Thawing Captain America project might have worked, but while it has interesting descriptions of how it’s possible to defrost frozen bodies at a constant rate to prevent decomposition, it’s one thing to thaw (while still preserving) something dead, and quite another for said frozen thing to turn out to be alive.

No matter how carefully (& scientifically) you thaw out a human body, there’s no way that frozen person could still be alive, and have survived the process of ACTUALLY FREEZING SOLID. The most important reason has to do with the fact that people have a lot of water in them. Why is this a problem? Well, when water freezes it gets bigger and it takes up more space. People have water in their cells, so when the water inside the cells freezes there’s a lot of damage done to the cells. (Intracellular freezing. It’s very bad for life expectancy). There are two ways this battle between ice and cells can go down. 1) ice formation leads to a concentration of minerals, which then causes cells to draw in too much water and burst, or 2) ice crystals being the pointy, poky things they are, they poke through the cell membrane, causing them to (you guessed it) burst. (2)

So it’s no surprise that recrystallization, (when small ice crystals lead to bigger ice crystals) would be something you’d want to avoid in a freezing body if you wanted that body to not be dead when you thawed it, and for the above reasons, organisms try really hardto make sure their blood doesn’t freeze. But sometimes you just can’t avoid subzero temperatures.

•…BUT SOME THINGS CAN.

After the super-soldier serum that turned Steve Rogers into Captain America, he was measurably different than other humans. He’s really strong, can jump crazy distances, survive huge falls without getting hurt, has enhanced cellular regeneration, can’t get drunk, and can, of course, survive being frozen for years and being thawed out. So, when looking for science to confirm the plausibility of Captain America surviving being frozen, using humans as a measuring stick isn’t the answer. And it turns out there are lots of organisms that have dealt with the conundrum of being both cold and alive.

•CAPTAIN AMERICA: THE WINTER FLOUNDER?

For some organisms, such as the winter flounder, the answer to cold temperatures is antifreeze blood. There are a LOT of different kinds of AFPs (anti-freeze proteins) / ISPs (Ice structuring proteins) [different names - same thing] but what they all have in common is they take care of that COLD = DEATH problem. How do they do this? The proteins bind to ice crystals to prevent the blood from getting frozen. Some AFPs do this better than others. Insect AFPs, for instance, work at colder temperatures than fish AFPs do.

Even if an organism has some kind of AFP, that doesn’t mean it’s out of the cold. There are two ways that you can deal with cold temperatures. You can be freeze avoidant, or freeze tolerant.

If you are freeze avoidant, congratulations - your blood will not freeze! But in really cold temperatures, your handy-dandy workaround may no longer work, and then death will soon follow…

If you are freeze tolerant, on the other hand, you will indeed freeze, but you will still be ok afterwards. The Alaskan beetle Upis ceramboides is one of those lucky freeze tolerant individuals.

So how does a freeze tolerant organism protect itself? The answer seems to include a fair amount of speculation. There’s a lot people don’t know about how different AFPs work. All of them inhibit recrystalization of extracellular ice. Some may stabilize cell membranes, control the rate of ice propagation, or prevent intracellular freezing. (3) (4)

Captain America looks pretty frozen, so it seems safe to bet he would have to be freeze tolerant.

•LEVELS OF AFPs RESPOND TO EXTERNAL STIMULI

This antifreeze ability doesn’t just hang around all the time. Usually it’s controlled by something: for example, the winter flounder “has a built-in annual cycle of antifreeze expression controlled by growth hormone (GH) release from the pituitary in tune with seasonal cues. ” (People know a lot more about winter flounder AFPs than other kinds, because they were studied the most.) (5) And in the beetle study, they say that “recrystallization inhibition and/or TH activity are known to increase in response to low temperature in freeze-tolerant insects, other anthropods, and plants.” (4)

•WHAT CAN SURVIVE BOILING, NUKING, EXTREME PRESSURE, AND THE VACUUM OF SPACE, + 30 YEARS IN ICE? (HINT: THE ANSWER ISN’T SUPERMAN)

It’s a Tardigrade, or water bear. These little animal-things are very strange. They can survive radiation and like, 10 years without food or water. In addition, they steal DNA from other things to add to their own. (6)

What does this have to do with Captain America being able to survive being frozen? Well, it’s another example that it can indeed be done (plus, Tardigrades are cool and weird.)

The way they survive so many extreme situations is through cryptobiosis, which is the key to crazy survival skills. Cryptobiosis is an ametabolic state an organism enters in extreme environmental conditions, in which metabolic processes stop, to resume upon the return of more livable conditions. Basically? It’s total stasis. There are different types of cryptobiosis, depending on what kind of environmental situation is being reacted to. Cryobiosis is when it happens in reaction to being very, very cold. (7)

•HOW IS CAPTAIN AMERICA LIKE A FROG?

So okay, you say. A flounder can survive being cold, a beetle can survive being frozen, and a tiny water bear can survive LITERALLY ANYTHING, but beetles and microscopic water creatures aren’t much like humans. Frogs aren’t much like humans either, but the wood frog rana sylvatica’s reaction to winter might be the best sci-fi resource for how Captain America could survive being frozen. They freeze right through! This article has information on how the freezing of the frogs is initiated, the stresses experienced during freezing and thawing, and how the frogs adaptations help them survive. For one thing, when the frog freezes, it moves water normally found in tissues to other parts of of the body, so ice forms in places where it won’t damage tissues and organs. It also uses glucose and urea to reduce ice formation, decrease cell shrinkage during freezing, and reduce cold-related injury; they enter cryobiosis, freezing for days or weeks. (8) (9) “The heart stops, all muscle and breathing movement cease and up to 70% of the body freezes (even the brain and the lens of the eye).” (10)

•SO, HOW HARD IS IT TO THAW SOMEONE SAFELY?

If you’re an animal made withstand being frozen, not very hard! This study describes an observation of the wood frogs’ thawing process, which concludes, “all basic physiological and behavioral functions usually [return] within several hours of thawing,” with sequential restoration of fundamental to complex vital functions. Here’s a list of how the frogs revive:

1) before ice has completely melted - cardiac contractions return
(the heart starts beating)
2) then pulmonary respiration (11) & perfusion of peripheral tissues (12)
(breathing starts again, blood starts circulating through tissues)
3) 1-2 hours after thawing commences - contractility in hindlimb muscles (13)
(hindlimb muscles become able to contract)
4) 5 hours - capacity of innervating sciatic nerve to propagate action potentials
(the sciatic nerve - a major nerve of the lower limb & the largest nerve in the body (14) - is stimulated to create the power for the muscle to contract (15))
5) several hours later - fundamental nervous functions are restored, ex. Hindlimb retraction/righting reflexes
(sensory input received, recognized, and responded to with motor action (16))
6) within 14-24 h of onset of thawing - normal body postures/coordinated motor functions

with the effect of freezing on complicated neurological functions unknown. (11)

So if Captain America thaws anywhere near as quickly, or in the same way, as a frog does, 1) someone must have been VERY surprised when they noticed his heart start beating again and 2) SHIELD made their special room for waking up Captain Americareally fast - in less than a day. No wonder the scenario had so many anachronisms! (12)

BIBLIOGRAPHY

LINKS
(1) http://moviepilot.com/posts/2947655
(2) http://www.doitpoms.ac.uk/tlplib/biocrystal/nucleation.php
(3) https://en.wikipedia.org/wiki/Antifreeze_protein
(4) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2787118/
(5) http://www.annualreviews.org/doi/10.1146/annurev.physiol.63.1.359
(6) http://www.sciencealert.com/the-tardigrade-genome-has-been-sequenced-and-it-has-the-most-foreign-dna-of-any-animal
(7) https://en.wikipedia.org/wiki/Cryptobiosis
(8) https://www.units.miamioh.edu/cryolab/projects/woodfrogfreezing.htm
(9) http://voices.nationalgeographic.com/2013/08/21/how-the-alaska-wood-frog-survives-being-frozen/
(10) http://www.earthtouchnews.com/wtf/wtf/5-animals-1-superbug-that-can-freeze-thaw-live
(11) http://www.preservearticles.com/201101133228/pulmonary-respiration.html
(12) http://medical-dictionary.thefreedictionary.com/tissue+perfusion
(13) http://teachmeanatomy.info/lower-limb/nerves/the-sciatic-nerve/
(14) https://en.wikipedia.org/wiki/Action_potential
(15) http://antranik.org/fundamentals-of-the-nervous-system-and-nervous-tissue/
(16) https://www.units.miamioh.edu/cryolab/projects/documents/CostanzoIrwinLee97.pdf
(17) http://cornflowershade.tumblr.com/post/111206875133/julianaegley-marguerite26-kk-maker