What is the biggest scientific hurdle really of getting critics off the ground? So people working in the field – what should they be focusing on? So what kind of translations and numbers would you both like to see? I heard that the preservation time between when your heart stops beating to when the first responder can come is a really interesting one. What are other potential challenges that you want to see solved here that could people make progress on?
- Emil: I’m mostly interested in doing stuff that can be implemented into the clinical practice of cryopreservation tomorrow. I don’t care about cells, I care about what we need to do to preserve humans in a real world situation. This is what we’re interested in funding. Ischemic time is a big issue. And of course Aschwin probably has a longer list and there’s a long list of smaller problems that need to be solved.
- Aschwin: It is to be expected when you’re working more on the scientific technical side of cryonics to give an answer like “if we can achieve this technological breakthrough, then will people sign up in mass.”
But one lived lesson is that if you dig really deep into why people don’t want to sign up for cryonics, you find very deep-rooted psychological objections. And a very important one is that people fear the sort of alienation of being kind of ejected alone into some kind of unknown future.
In terms of the scientific and technological breakthroughs, I think we are already there in terms of being able to cryopreserve in a way that we can infer the original condition of the brain. I think we are already at that station for some time, in my opinion it’s even compatible with what we call “straight freeze”, provided there’s no ischemia.
But there are three technologies where it would be good to put more emphasis on:
- More rapid cooling in the beginning of procedures, and there are two ways of doing that. One is called liquid ventilation, in which you basically use human lungs as a heat exchanger by pumping in and out the very cold liquid, and that allows you to cool really quick.
- Another innovation that is already kind of available is intermediate temperature storage. Right now if you store a cryopreserved patient at liquid nitrogen temperature, whether it’s whole body or neuro, you will have some degree of fracturing because the vitrification agent solidifies at around -130 and we are stored at -196 so that causes a lot of thermal stress and and fracturing. If you’re really into molecular nanotechnology, you might say that it is not really that big of an issue in the bigger scheme of problems – and you’re probably right about that – but in terms of promoting and marketing cryonics that is a big deal for people.
- One other thing is that I think it’s really about time that we show recovery of organized brain electricity in a cryopreserved brain. That’s actually something my lab is working on, but is actually a hard model – most of the challenges are in the modelling there. But I think that would be very powerful, because you can say that if a brain is cooled down really quickly and vitrified, that brain is still capable of function, so cryonics patients should have some kind of legal standing, even if it’s not the same as normal human beings. You cannot have a person whose brain activity is potentially recoverable treated the same as someone who is dead.
So I think those would be some of the powerful things we can do in the next 10 years.
So I’ve read that there are some unpleasant things happening to our proteins during the freezing process, so for instance if we use cryoprotectants, they usually pull out water outside of cells. Water molecules give stability to our proteins and thus the dehydration leads to loss of conformation of different proteins in the cells, and then they tend to aggregate and during the thawing process, cells might partially lose the information stored in this these particular proteins – so a cell can become viable again but due to synthesis of new proteins, the memory, that was encoded presumably in some proteins, has been lost. And what about other damage – during freezing there is ROS degeneration – reactive oxygen species damage the DNA, also there are some changes and alterations in methylation and epigenetics. What do you think about the influence of this process on the information content of the freezed brain? Will it significantly alter it or not?
- Aschwin: A lot of that depends on how we think memory and identity are encoded – at which level, ranging from atoms to the connectome. If you see the work on the neural anatomical base of memory, you typically see electron micrographs of synapses and axons and connections.
Now if you would take these images and replace the proteins with proteins that are denatured; it would not even be able to detect that in electron micrographs. That of course doesn’t mean that we should not care about it, because clearly if you reverse the process, and a lot of proteins have been negligibly affected by these high concentration cryoprotectants, there will not be any biological viability. That’s why we often draw this distinction in cryonics and cryobiology between structure and viability.
Vitrification (solidification) without ice formation is actually really easy to do. That’s sometimes a misunderstanding that it took a long time to achieve vitrification, but if you use a high enough concentration of cryoprotectants, it is actually easy. The challenge is to use a mixture of cryoprotectants that leaves the molecular machinery of the cells – the proteins – in an intact state.
As you indicated yourself, one of the mechanisms by which you can disrupt the molecular machinery is by using “glass forming” cryoprotectants at high concentrations. They are really powerful, they basically negatively affect the hydration shell of proteins.
- There is one thing that we found out in the cryobiology community, specifically Greg Fahy and Brian Wowk at 21st Century Medicine – until recently it was conventional wisdom that the higher the concentration of the cryoprotectant, the more toxicity, the more effects on proteins. But what we actually found is that a high concentration of weaker “glass formers” – that leave the biological structure of the cells intact – is actually less toxic than a lower concentration of a cryoprotectant that is more powerful.
- The next thing I wanted to mention, which might be only for limited relevance to cryonics, because it’s generally agreed in our community that we will not re-warm the patients and then start conducting repairs, the initial repairs will be done at cryogenic temperatures via “cryorobotics”.
However I wanted to make a little announcement. By the end of the year, at the latest early next year, there will be the first first full length – and i’m talking about more than 800 pages – protocol of how to assess the damage of a typical cryo patient at cryogenic temperatures and do some of the initial repairs at cryogenic temperatures. And if and when you’ve done that, then you can make final repairs up to the point where everything functions at normal again, and then you would initiate revival.
So it will never be the case that you would just warm up the patient and all these processes that had been set into motion – ischemia, protein denaturation – will just continue to unfold, which would prevent any kind of meaningful revival. So a lot of the preliminary revival work will be done at cryogenic temperature.
Even people who are cryopreserved under really good conditions will probably need some kind of molecular modifications, including further protection against ice formation – because if you warm up, there’s again a possibility that there’s ice formation because it could just be that you were just avoiding it and then when you warm up, then you have all this ice nucleation that turns into ice formation.
So a lot will be done as we envision it now at cryogenic temperatures and then the revival process will take place.
Just to make it clear, I am not saying that memory should exist somewhere in the proteins, but if we’re talking about the synaptic network – the connectome – you need not to know only the information about which axon with which dendrite is in contact, but also the type of synapse, and this is determined by ion channels that exist on the membrane, and they can be affected by the cryoprotectants, by the freezing procedure, by all of these factors. It would be interesting to know whether there are studies that basically looked into what happens with the proteins that basically encode information about the synapse itself.
- Aschwin: One thing I should mention is that the repair will take place at cryogenic or a high sub-zero temperature, but probably will also be done after making a very detailed scan, and how detailed that scan needs to be is probably one of the main questions about the revival of cryonics patients. You can of course simulate the brain in silico. Regardless of what you think about something like substrate independent mind, whether it is feasible or not, that actually doesn’t matter – you can at least simulate that in a model and see if it is working again. They’re all kinds of safeguards I think that you can build in to prevent scenarios where you miss something about how the brain works and then you warm up and it’s gone.
Let’s imagine we take a deceased patient many hours after death. We know that there are many blood clots inside the body. What about thrombolytic therapy? Can we use thrombolytic mechanisms as an addition to the cryoprotectants for patients that are being cryopreserved after a long amount of ischemic time?
- Emil: We are already using thrombolytic agents, and we’re actually starting a research project on that with Aschwin just now to see if a larger amount of thrombolytic agents have a positive effect.
It seems like an age-old debate in this field – when will we see a solution to these debates? I don’t understand why it is such a controversial area in the cryogenic field.
- Emil: The main problem in this whole field, unfortunately, is that there is very little research money right now. There’s significantly more research to be done to figure out all these questions, so a lot of these questions have relatively little research or indirect research backing. A lot of research needs to be done in this field. In the end that is kind of the reason why we’re building this organization – to offer more than a service – to be able to funnel money from the service to the research and conduct research experiments. This is also why there is a relatively limited amount of consensus in this whole field, there just isn’t enough research to actually know.
You Aschwin seem to be favoring cryo repair at cryo temperatures, but a lot of the damage would occur in tissues as you’re warming up – denaturation, fallout damage, etc. It seems like an area where a lot of progress would need to be made in the future – some sort of progressive monitoring of the process or progessive repair or protection against that damage as you warm up. But you seem to be favoring – talking about the whole field – that repair would occur at cryo temperatures rather than as the tissue is being warmed up. You don’t see that as an important step for an addressable model?
- Aschwin: A lot of the cryoprotectant toxicity happens even much earlier, not even warming, but when they are introduced to the tissues. And that’s why one of the best ways to avoid cryoprotectant toxicity is to load an organ at low temperatures and limit the exposure time of the cryoprotectant. That also means that there is a tradeoff between exposure time and what we call osmotic damage. Because if you load the cryoprotectant way too fast, then you also damage the cells.
But to get to your point about the potential for that kind of damage happening again when you warm up. The idea when I talked about doing the initial repairs at cryogenic temperatures is of course not that you fix these things and warm up and then it happens again. I think it’s pretty much agreed in our field that there won’t be any revival attempts absent any kind of very mature molecular nanotechnology. So when I say repairs at cryogenic temperatures, that would be the initial assessment and review and stabilization, and probably removing the vitrification agent, replacing it with something even more potent, accessing all the vessels and making sure it can be warmed up safely.
During that process, we would expect molecular machines to really stabilize tissues in a way that when you warm up, the normal mechanisms of cryoprotectant injury and toxicity would not happen. So it’s not like we would just warm up like we would warm up today. It would be a very controlled molecular medicine based warm-up.
Now that is a luxury we probably have in cryonics. If you talk about conventional organ preservation, those people don’t have that, so if you preserve a kidney for organ transplants today, you’re not talking about molecular nanomedicine. In that process you have to reduce cryoprotectant toxicity basically to zero and warm up fast enough that any of these mechanisms don’t kick in and prevent this kind of process from unfolding. So we aim for that ideal in cryonics, one advantage we have is that we are not required to do any kind of warm-up before we have this molecular machinery to hold things really stably into place.
The book I mentioned goes into detail on hundreds of pages into specific molecular inhibition strategies during the warm-up process that prevents the damaging mechanisms from unfolding. But again, for conventional organ preservation these things are of course not available yet and not working. That’s why perfecting normal organ preservation is very hard.