From Alcor President, Max More
February 12, 2016
In December 2015, 21st Century Medicine, Inc. published peer-reviewed results of a new a new cryobiological and neurobiological technique, aldehyde-stabilized cryopreservation (ASC) that provides strong proof that brains can be preserved well enough at cryogenic temperatures for neural connectivity (the connectome) to be completely visualized. And this week the Brain Preservation Foundation (BPF), after independent evaluation by neuroscientists Dr. Sebastian Seung, Professor at Princeton, and Dr. Ken Hayworth, President of the BPF, awarded The Small Mammal Brain Preservation Prize to 21st Century Medicine based on these results.
The BPF press release says: “it is the first demonstration that near-perfect, long-term structural preservation of an intact mammalian brain is achievable, thus directly answering what has been a main scientific criticism against cryonics.”
Many people are wondering whether Alcor plans to adopt the “Aldehyde-Stabilized Cryopreservation” (ASC) protocol used to win the prize and what the win means for cryonics in practice. Alcor’s position is as follows:
We are pleased that vitrification, the same basic approach that Alcor Life Extension Foundation has utilized since 2001, is finally being recognized by the scientific mainstream as able to eliminate ice damage in the brain. Alcor first published results showing this in 2004. The technology and solutions that Alcor uses for vitrification (a technology from mainstream organ banking research) were actually developed by the same company that developed ASC and has now won the Brain Preservation Prize.
ASC under the name “fixation and vitrification” was first proposed for cryonics use in 1986. ASC enables excellent visualization of cellular structure – which was the objective that had to be met to win the prize – and shows that brains can be preserved well enough at low temperature for neural connectivity to be shown to be preserved. Current brain vitrification methods without fixation lead to dehydration. Dehydration has effects on tissue contrast that make it difficult to see whether the connectome is preserved or not with electron microscopy. That does not mean that dehydration is especially damaging, nor that fixation with toxic aldehyde does less damage. In fact, the M22 vitrification solution used in current brain vitrification technology is believed to be relatively gentle to molecules because it preserves cell viability in other contexts, while still giving structural preservation that is impressive when it is possible to see it. For example, note the synapses visible in the images at the bottom of this page.
While ASC produces clearer images than current methods of vitrification without fixation, it does so at the expense of being toxic to the biological machinery of life by wreaking havoc on a molecular scale. Chemical fixation results in chemical changes (the same as embalming) that are extreme and difficult to evaluate in the absence of at least residual viability. Certainly, fixation is likely to be much harder to reverse so as to restore biological viability as compared to vitrification without fixation. Fixation is also known to increase freezing damage if cryoprotectant penetration is inadequate, further adding to the risk of using fixation under non-ideal conditions that are common in cryonics. Another reason for lack of interest in pursuing this approach is that it is a research dead end on the road to developing reversible tissue preservation in the nearer future.
Alcor looks forward to continued research in ASC and continued improvement in conventional vitrification technology to reduce cryoprotectant toxicity and tissue dehydration. We are especially interested in utilizing blood-brain barrier opening technology such as was used to win the prize (but which pre-dated work on ASC).
It may remain unclear to many whether this research result shows whether ASC or current vitrification without pre-fixation is more likely to preserve cell structures and molecular structures necessary for memory and personal identity. What we can note is that Robert McIntyre, the lead researcher on ASC at 21st Century Medicine, made a point during his presentation at the Alcor 2015 Conference of recommending against adoption of ASC in cryonics at this time.
For cryonics under ideal conditions, the damage that still requires future repair is now more subtle than freezing damage. That damage is believed to be chiefly cryoprotectant toxicity and associated tissue dehydration. It’s time for cryonics debate to move past ill-informed beliefs of “cells bursting.”
This is a groundbreaking result that further strengthens the already strong case that medical biostasis now clearly warrants mainstream scientific discussion, evaluation, and focus.
More a more detailed statement, and one that Alcor endorses, see:
http://www.evidencebasedcryonics.org/media/MBPP.pdf
