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Rejuvenation Research
© Mary Ann Liebert, Inc.
DOI: 10.1089/rej.2020.2356
1
Rejuvenation Research
Cryonics takes another big step towards the mainstream (DOI: 10.1089/rej.2020.2356)
This paper has been peer-reviewed and accepted for publication, but has yet to undergo copyediting and proof correction. The final published version may differ from this proof.
Cryonics takes another big step towards the mainstream
Aubrey D.N.J. de Grey
SENS Research Foundation, Mountain View, USA
Email: aubrey@sens.org
“You're dead when a doctor says you're dead.” – James Bernat
A lot progress, both technological and political, has occurred in cryonics since Ben Best
made his scientific case for cryonics in this journal in 2008.1 Among the most encouraging
examples were the demonstration of retention of memory in nematode worms after
cryopreservation and revival, also published in RR,2 and the emergence of an
unprecedentedly authoritative consensus around the feasibility of preserving complex
mammalian tissues.3
One common objection to the theory and practice of human cryopreservation is that it can
only work under ideal circumstances because the brain “dies” within minutes. This issue of
Rejuvenation Research contains a comprehensive study to understand the ultrastructural
effects of circulatory arrest on the mammalian brain.4 The authors of this paper show that
ischemia-induced damage to the brain is a time- and temperature-dependent process. It
takes many hours of normothermic global ischemia, and several weeks of cold global
ischemia, to damage the fine structure of the brain to a degree that the original structure
of the brain cannot be recognized or inferred. The researchers also introduce a novel deep
learning algorithm that can distinguish the early stages of permanent cerebral ischemia
from the late stages of permanent cerebral ischemia by looking at electron micrographs
alone. The paper concludes by speculating that future computational technologies can re-
construct the pre-ischemic state of the brain from the ischemic state. They call this
discipline “reconstructive connectomics” and its methods could also be used to infer the
non-frozen state from the frozen state (if there is freezing damage), providing an
important tool-set to permit biological repair and revival of cryonics patients preserved in
non-ideal circumstances.
Today, human cryopreservation is practiced as a form of experimental emergency
medicine in which standby teams are deployed to the bedside of a terminally ill person to
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Page 2 of 4
2
Rejuvenation Research
Cryonics takes another big step towards the mainstream (DOI: 10.1089/rej.2020.2356)
This paper has been peer-reviewed and accepted for publication, but has yet to undergo copyediting and proof correction. The final published version may differ from this proof.
start their procedures as soon as the person is pronounced legally dead. The delays and
complex logistics entailed in this process are often perceived as intrinsic to the process of
human cryopreservation. In principle, however, human cryopreservation can be practiced
as an elective medical procedure in which the transition between the decline of a terminal
patient and the start of cryonics procedures is managed by medical professionals. The aim
of human cryopreservation as an elective medical procedure is distinctly different from
palliative care or euthanasia because the objective would be to save a life, not end it.5 The
degree to which human cryopreservation as a hospital-based procedure draws upon
mainstream disciplines such as critical care medicine, anesthesiology, extracorporeal
perfusion, and cryobiology, warrants the name Medical Biostasis for this emerging
approach.
In 2019, for the first time, a detailed human Medical Biostasis Protocol was published to
document what such a procedure could entail.6 This document is the culmination of a
collaborative effort of cryobiology researchers and medical professionals. The protocol
does not just provide a detailed set of guidelines for hospital-based medical biostasis but
also suggests lab-based methods to evaluate the efficacy of the procedure and identifies
areas for further experimental research. The introduction to the document reads as
follows:
Medical biostasis is an experimental procedure that induces metabolic arrest at
cryogenic temperatures to allow terminally ill patients to benefit from future
medical advances and restore them to good health. Practiced as a hospital-based,
elective medical procedure, medical biostasis consists of three distinct procedures:
induction of hypothermic circulatory arrest, cryoprotection, and long-term care at
intermediate temperatures (between -120
℃
and -130
℃
). This document sets out a
detailed protocol for medical biostasis, outlines a variation of this protocol for out-
of-hospital emergency cases, and outlines research directions to further optimize
this protocol.
In ideal circumstances this protocol permits maintaining viability of a patient’s brain by
contemporary medical criteria until about halfway of cryoprotectant perfusion, after which
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3
Rejuvenation Research
Cryonics takes another big step towards the mainstream (DOI: 10.1089/rej.2020.2356)
This paper has been peer-reviewed and accepted for publication, but has yet to undergo copyediting and proof correction. The final published version may differ from this proof.
point the aim of the procedure is preservation of the fine structure of the brain for long-
term cryostasis.
Given the slow mainstream medical acceptance of human cryopreservation, it is not likely
that this document will be fully used by a hospital in the West in the foreseeable future.
Having an evidence-based protocol for clinical human cryopreservation, however, can
assist researchers and medical professionals to review medical biostasis procedures and
understand the rationale for various components. This protocol also is useful for critics to
recognize the difference between what “good cryonics” would look like and the protocols
that existing cryonics providers currently are compelled to do.
Existing human cryopreservation providers can also draw upon this protocol to further
improve and refine their procedures because not all procedures outlined in the document
require a hospital-based elective medical procedure (for example, improved monitoring of
the brain cryopreservation).
The difference between “old school” cryonics and medical biostasis is not black and white
as evidenced by the fact that the new Chinese cryonics provider Yinfeng uses rapid
extracorporeal perfusion technologies for its initial stabilization part of a patient.
The current COVID-19 pandemic has drawn unambiguous attention to the social and
economic costs of immunosenescence, one of the main targets for rejuvenation
biotechnologies in the SENS program. Rejuvenation technologies are not likely to be
available in time for very old and terminally sick people. Medical biostasis presents the
only practical and evidence-based means of survival for them. The case for using “The
Arrest of Biological Time as a Bridge to Engineered Negligible Senescence” has further
grown in credibility since its 2004 exposition in The Annals of the New York Academy of
Sciences7 and warrants further scientific and medical scrutiny. Exposition of a detailed
protocol to conduct human medical biostasis by medical professionals is an important
contribution to this endeavor.
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Page 4 of 4
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Rejuvenation Research
Cryonics takes another big step towards the mainstream (DOI: 10.1089/rej.2020.2356)
This paper has been peer-reviewed and accepted for publication, but has yet to undergo copyediting and proof correction. The final published version may differ from this proof.
References
1. Best BP. Scientific justification of cryonics practice. Rejuvenation Res 2008;
11(2):493‐503.
2. Vita-More N, Barranco D. Persistence of Long-Term Memory in Vitrified and Revived
Caenorhabditis elegans. Rejuvenation Res 2015; 18(5):458-463.
3. Lewis JK, Bischof JC, Braslavsky I, Brockbank KGM, Fahy GM, Fuller BJ, Rabin Y,
Tocchio A, Woods EJ, Wowk BG, Acker JP, Giwa S. The Grand Challenges of Organ
Banking: Proceedings from the First Global Summit on Complex Tissue
Cryopreservation. Cryobiology 2016; 72(2):169-182.
4. de Wolf A, Phaedra C, Perry RM, Maire M. Ultrastructural Characterization of
Prolonged Normothermic and Cold Cerebral Ischemia in the Adult Rat [published
online ahead of print, 2020 Mar 12]. Rejuvenation Res. 2020; this issue.
5. Minerva F, Sandberg A. Euthanasia and Cryothanasia. Bioethics 2017; 31(7):526‐533.
6. de Wolf, A. Medical Biostasis Protocol. 2019;
https://www.biostasis.com/protocol.pdf
7. Lemler J, Harris SB, Platt C, Huffman TM. The arrest of biological time as a bridge to
engineered negligible senescence. Ann N Y Acad Sci 2004;1019:559‐563.
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