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8 March 2017

Nanowarming Breakthrough Could Save Lives & Boost Cryopreservation Efforts

Cryopreservation has received a lot of attention in recent years. Hailed by some as the pathway to immortality, the number of people opting to undergo the process has increased each year, despite the fact that scientists currently have no way of reviving frozen individuals.

The techniques used to freeze organs and, in some cases, entire bodies for the purpose of long-term preservation have seen much development and innovation over the years, with scientists now claiming that vitrification - the super-cooling of tissues into a glass-like state – could be the most viable option for the indefinite storage of tissues in fields such as transplantation and cryopreservation. However, the defrosting process hasn’t kept pace, meaning that when tissues and organs are rewarmed and brought out of a cryogenically frozen state, it leads to irreparable damage as a result of cracking or crystallisation.

Now, a team out of the University of Minnesota, led by Navid Manuchehrabadi, have published a study to the journal Science Translational Medicine which demonstrates a technique which could revolutionise the rewarming aspect of cryopreservation, known as nanowarming.

Nanowarming works by first creating a solution of iron oxide particles. Heat is then generated via the use of an external magnetic field, which warms the solution in a uniform manner. The tissue is then suspended into the cryoprotectant solution and defrosted as heat is applied. The team tested the technique on samples of pig heart tissue, pig arteries, and frozen human skin cells; at the tested scale, no signs of damage were observed in the tissue. Residual iron oxide nanoparticles are then washed away, and the organ is ready for transplant, in theory.

Img: Science Translational Medicine
I say in theory because the tests were all carried out on small tissue samples, and there may be additional unforeseen difficulties encountered when the process is scaled up. The researchers are however confident that the nanowarming process could be adapted to defrost full-scale organs and tissues up to and above volumes of 1ltr, saving countless lives by transforming the field of organ transplantation.

“With continued breakthroughs in preconditioning and/or post-conditioning of organs, improved perfusion and vitrification protocols, and other enabling technologies that are being brought to bear to successfully vitrify human organs, we believe that nanowarming can converge with and enable these technologies to help make organ cryopreservation a reality,” the researchers state.

“The maximum tolerable organ preservation for transplantation by hypothermic storage is typically four hours for heart and lungs; eight to 12 hours for liver, intestine, and pancreas; and up to 36 hours for kidney transplants,” they continue.

“In many cases, such limits actually prevent viable tissue or organs from reaching recipients. For instance, more than 60% of donor hearts and lungs are not used or transplanted partly because their maximum hypothermic preservation times have been exceeded. Further, if only half of these discarded organs were transplanted, then it has been estimated that wait lists for these organs could be extinguished within two to three years.”

The plan now is to move onto testing on rat and rabbit organs before scaling up to pig organs, as the latter are known to be biologically similar to human organs and have even been successfully used in xenotransplantation.

John Bischof, senior author of the study, said, “These results are very exciting and could have a huge societal benefit if we could someday bank organs for transplant.

“We will have to actually go to a larger system if we want to move into human organs but there's nothing that precludes us from doing that. The technology does exist, the instrumentation, the coils etc., exist for us to scale up.”

So where does this leave us in our quest to cryopreserve entire bodies for later resurrection? Well, according to Bischof, while the idea is achievable in theory, we are far from having the capability today
“I suppose, once you have done a whole organ, there is a certain intellectual connecting of the dots that takes you from the organ to the person. So I guess there is, if you can build a large enough radiofrequency coil and you can get all the nanoparticles in, I suppose I could see somebody making this argument,” Bischoff states.

“There are some huge scientific hurdles ahead of us. And so I think it's rather premature to think about getting into a whole person.”

Kelvin Brockbank, another study author, further quashed the dreams of those hoping to recreate the experience of Philip J. Fry, asserting that, “The cryonicist movement will probably distort the importance of this to being able to preserve whole human bodies quite quickly. However, I believe that even if we could preserve the whole body, the chances that the neural pathways, which have been established during life, being maintained in after (during and after cryopreservation) are probably remote, at this point. And so I don't believe that we will be seeing success for whole bodies within the next 100 years.”

Sam Bonson

Sam is an aspiring novelist with a passion for fantasy and crime thrillers. He is currently working as a content writer, journalist & editor in an attempt to expand his horizons.