The Quest To Reverse Death Inches Closer To Success

• A new startup called Cradle is developing the means to preserve human organs and eventually entire bodies indefinitely at extremely low temperatures.
• They recently published research showing for the first time that mammalian brain tissue preserved in this way can recover electrical activity after thawing, providing a proof of concept that whole brains and other organs might eventually be preserved.
• The research could have more immediate implications, like making it easier for scientists to study human brain tissue.

If you found yourself the sole survivor on a sinking ship in the middle of the ocean, would you simply accept your fate and go down with the ship, or would you jump into the water and grab hold of a piece of wreckage? Most people would choose the latter: your chances of being rescued might be low, but death is guaranteed if you remain on the ship. Yet many people still mock the idea of cryonics – the effort to preserve the bodies of dead humans at very low temperatures so that they can one day be restored to life when the necessary technology becomes available.

How does cryonics work?

While most people think of death as a single point in time, cryonicists do not view things this way. If a person’s heart stops while they’re hiking in the mountains, their life has almost certainly come to a permanent end, but were they instead in a hospital surrounded by doctors, their heart potentially be restarted. Even though we may call one person dead and one alive, there is nothing biologically different about these two people at the moment their hearts stopped. What really matters is whether the biological damage a person has sustained can be reversed. Cryonicists think that if someone’s body can be preserved quickly enough after their vital functions have stopped, we will eventually have the technology to undo whatever killed them.

We went into great depth concerning the technology being used for human cryopreservation in this article. In brief, the technology needed to preserve human cells indefinitely already exists and is used routinely for things like IVF, in which embryos are stored at around -200 degrees. It involves the use of chemicals called cryoprotectants to prevent water from forming ice crystals that would damage cells. Instead, molecules are immobilised in a process called vitrification. Problems arise when trying to store larger things, like a brain or an entire human body. In particular, most cryoprotectants are toxic, which will pose a significant challenge whenever the time comes to reverse the process.

Cryonics is an optimist’s field: it requires a belief that the challenges of reversing cryopreservation can be overcome, that medical technology will be much better in the future, that the cryopreservation of an individual will not be interrupted before that future arrives, and that the world of that future will be worth living in. That optimism seems to be spreading slowly but surely, and with it comes new organisations and more funding.

Introducing Cradle

A few weeks ago, a cryonics startup called Cradle was announced with $48 million in funding. It is co-founded by venture capitalist Laura Deming, who also founded the Longevity Fund and has a scientific background in genetic engineering of lifespan extension, alongside chief scientist Hunter C Davis, whose research focuses on biomolecular tools and imaging techniques.

This announcement coincides with their release of a white paper showing that a slice of brain tissue from a rat could be cryopreserved and still regain some electrical activity after being thawed. If replicated, this will be a first for mammalian brain tissue, and brings us one step closer to being able to preserve human brains – the most challenging organs to preserve without causing irreparable damage. The techniques used were not particularly revolutionary – the experiment used an already established combination of cryoprotectants (save for the removal of a single chemical), rapidly cooled the tissue to -196 degrees Celsius with a jet of liquid nitrogen, and reheated it with an induction heater over the course of about 15 seconds.

So, what’s next? Cradle ultimately wants to achieve cryopreservation of organs from large animals, which would then lead to human clinical trials. Being able to cryopreserve human organs would vastly improve patients’ chances receiving a well matched organ transplant, since any organ that became available could be put in storage until needed. To help them achieve these goals, Cradle is working on new less toxic cryoprotectant molecules, as well as developing improved means to perfuse organs with cryoprotectants and to cool and warm them more rapidly, which is important for successful preservation. Of course, Cradle also have their eyes on whole-body cryopreservation, and hope to eventually test this in a small animal model.

While these are lofty goals, there are immediate applications to this research. Currently, the vast majority of science studying neural networks in the brain uses tissue from rodents, as by the time donor tissue from human brains reaches the lab, much of the intricate connectivity between cells will have degraded. Cryopreservation of human brain slices could make study of electrical activity within our own brains much easier, which would increase the translatability of research findings.