Brain Preservation and Personal Survival: The Importance of Promoting Cryonics-Specific Research

The Brain Preservation Foundation’s mission to validate structural preservation of the brain has been very successful but the link with mind uploading as a means of personal survival raises some important questions. Alexandre Erler makes the case for a distinct cryonics research program based on biological survival.

INTRODUCTION: CRYONICS AND THE BRAIN PRESERVATION FOUNDATION

As someone who is fully supportive of the ultimate goals of the cryonics enterprise, but still views the current state of the practice with some degree of skepticism, I make a point of acquainting myself with the latest evidence regarding the quality of cryonics procedures and their ability to preserve the foundations of a person’s identity through time. Over the past two years or so, I have increasingly seen a recent achievement by 21st-Century Medicine (21CM) cited by some cryonics supporters as demonstrating the scientific validity of those procedures: namely 21CM’s research on aldehyde-stabilized cryopreservation (ASC). This new technique has allowed them to win, in 2016, the Small Mammal Prize, and just this year, the full Technology Prize awarded by the Brain Preservation Foundation (BPF), by demonstrating excellent preservation of the ultrastructure in, respectively, a whole rabbit brain (McIntyre and Fahy, 2015) and a whole pig brain (The Brain Preservation Foundation, 2018). Were I to follow this line of reasoning, I could happily set aside my concerns about the adequacy of today’s cryopreservation procedures, which had now been verified by scientific experts; the proper focus would now need to be on how to responsibly introduce those procedures into a clinical setting, for patients at the end of their lives who might request them.

It turns out, however, that things are not so simple. ASC is no doubt a step forward for the field of brain banking, and as its name indicates, it it is indeed a form of cryopreservation, since it involves vitrification of the brain at -135 °C. Nonetheless, ASC does not count as cryonics, insofar as it uses a fixative solution prior to vitrification and cooling, which could potentially preclude revival of the original biological brain (an essential part of cryonics as traditionally understood). And indeed, biological revival with the help of future technology is not a priority for the BPF’s president, Dr Kenneth Hayworth. Rather, he envisages brain preservation as conducive to life extension via mind uploading: a process that would involve cutting the preserved brain into thin slices, scanning each slice, and feeding the resulting data to an advanced computer that would thereby be able to map out the entire network of neural connections in the person’s original brain, and ultimately to emulate that person’s mind (Hayworth, 2010). This is quite different from cryonics.

Assuming that a technique like ASC is compatible with mind uploading, but not with the revival of the original brain, it should not be treated as a landmark in cryonics research. Admittedly, there is some uncertainty about the truth of that assumption. It seems at least conceivable that the chemical cross-links created by the fixation process could be reversed, and the original brain revived, using future technology. Nonetheless, ASC introduces empirical and philosophical uncertainties (e.g. could we really restore, as opposed to recreating, the original neural structure following the various molecular changes involved?) to a much greater degree than traditional cryonics does.

But why, it might be asked, should one remained fixated on pursuing biological revival via cryonics, if the evidence in favour of good ultrastructure preservation is better for ASC than it is for contemporary cryonics procedures? It is for instance known that, up to now, 21CM’s cryonics protocol involving the use of cryoprotectant M22 has been causing the brain to shrink to almost 50% of its natural size due to osmotic dehydration, hindering our ability to establish the quality of ultrastructure preservation using electron microscopy (The Brain Preservation Foundation, n.d.; De Wolf, 2017). If so, why not join the BPF in focusing simply on the type of brain preservation that seems to yield the best evidence of success, even if this means turning away from cryonics towards mind uploading?

In what follows, I will argue that, given the current state of our scientific and philosophical knowledge, doing so would be irresponsible. The BPF’s commitment to holding brain preservation research to the highest standards of scientific rigour is laudable, and worth emulating. Nonetheless, for those interested in brain preservation with a view to enabling life extension, supporting cryonics-specific research remains the safer bet. We should not simply rely on the BPF’s approach if our goal is to try and save those whom medicine in its current state cannot restore to life and health.

TWO DIFFERENT VIEWS ABOUT PERSONAL IDENTITY AND SURVIVAL

To see why this is so, let us begin by noting the two main philosophical theories of personal identity through time that are relevant when discussing the respective merits of cryonics and mind uploading in this context. The first one, which we can call the “Physical Continuity” (PhyCon) theory, asserts that a person is identical with the physical substratum from which her mind emerges: that is to say, her brain, with its intricate web of neurons and synaptic connections. (For a good exposition of the theory, see e.g. McMahan, 2002.) According to this theory, saving a person from destruction after she has been pronounced dead requires preserving enough of her brain, in a state in which that brain retains at least its potential for viability. What exactly counts as “enough” of the brain is of course a difficult question that would deserve much more discussion. While we can safely say that, all else being equal, it is always preferable to preserve as much of the original brain as we can, the survival of the person arguably does not require perfect preservation. Intuitively, people can survive limited forms of brain damage, such as those caused by strokes. What is more, as cryonicists have pointed out, brain damage that causes significant disability today might no longer be a serious problem (as long as it is limited enough not to undermine personal identity) in a future where cryonic revival has become possible, as the technological means will then likely exist to fully repair that damage, e.g. based on inferences from the state of the person’s brain prior to repair.

The second relevant theory can be referred to as the “Psychological Continuity” (PsyCon) theory. Roughly speaking, it says that you are to identical with the set of psychological features (memories, beliefs, desires, personality traits, etc.) that constitutes your mind. On this view, preserving you after you have been pronounced dead requires ensuring the persistence of enough of those psychological features, in an embodied mind of some sort (but one that need not be embodied in your current biological brain). One variant of PsyCon, endorsed by many supporters of mind uploading including Hayworth, states that preserving a person after legal death requires preserving her connectome, understood as the mapping of neural circuitry encoding one’s memories, skills, and other psychological features – that is to say, the connectome as an informational entity rather than a physical one (Hayworth, 2010), even though the information in question will by necessity be stored in some physical substratum, whether a brain or a computer.

Like virtually all philosophical theories, both the PhyCon and PsyCon theories have their partisans and detractors. PhyCon, for instance, has been said to imply that there is a fundamental difference between a scenario in which a person had her brain suddenly destroyed and replaced by an exact copy of it, perhaps produced via scanning and 3D printing using neurons as basic material; and a scenario in which the person’s brain cells were gradually replaced by new ones over an extended period of time, in the same way as the rest of the human body regularly regenerates itself. While most PhyCon theorists would agree that the second scenario is compatible with the preservation of the person’s identity through time, they will deny that the first is – if the original brain gets destroyed, they will say, so must the person as well, and the new replica brain must belong to a new person not numerically identical with the first one. Some find this difference of treatment between the two scenarios arbitrary (e.g. Parfit, 1984).

Some versions of PsyCon, on the other hand, imply that multiple copies of yourself could all be you. Indeed, suppose that after scanning your brain to obtain a map of your connectome, we then created two identical copies of your mind running on two different computers. Since both copies would demonstrate the same degree of psychological continuity with your previous self, we would have to conclude that both are you – something many find intuitively unacceptable. Other versions of PsyCon strive to avoid that implication by stipulating that you are only identical with an upload of your mind if no more than one copy of it has been created, yet this move leads to other philosophical problems. Hayworth, however, happily endorses the implication that multiple copies of a single individual can co-exist at the same time, and contends that those who object to that implication are simply confused (Hayworth, 2010).

HOW TO MAKE A PRUDENT CHOICE UNDER (PHILOSOPHICAL) UNCERTAINTY

For the record, I personally find PhyCon more plausible than PsyCon (although I also agree that the preservation of one’s psychological features after cryonic revival is highly desirable, regardless of its significance for sheer survival). On that basis, I do not support further animal research targeted exclusively at the development of mind uploading technology. However, my personal opinion on the matter can be set aside for the sake of the present discussion. The important fact is that there are reasonable, honest and intelligent people on both sides of that debate, and that neither side has so far managed to present arguments that would convince all reasonable people on the other side. In such a situation, the intellectually responsible path to take is surely to eschew certainty, and acknowledge that the other side could be right, even if one thinks that this is unlikely and that the arguments favoring one’s own position are very strong.

If that is the case, what is the prudent choice to make for those who wish to promote life extension through brain preservation? I submit that traditional cryonics is the more prudent option to pursue. (This remark could be extended to ASC if one could show that it is in principle compatible with the revival of the original brain, and provided that it is not combined with destructive mind uploading.) This can be demonstrated using a simple argument that considers what the implications are if we assume that PhyCon and, respectively, PsyCon are true.

Suppose first that PhyCon is true. If so, a cryonics procedure carried out properly will save a person’s life, whereas using a technique like ASC that compromises the brain’s potential for viability, followed by destructive scanning and uploading, will kill that person. If PsyCon is true, on the other hand, both methods can ensure survival. Indeed, adequate cryonic preservation of a person’s brain would also preserve the ultrastructure grounding the various psychological features that defined that person. Insofar as traditional cryonics (at least once sufficiently perfected) can secure survival whether PhyCon or PsyCon is true, whereas mind uploading of the kind envisaged by the BPF can only do so if PsyCon is correct, traditional cryonics is the safest bet.

This conclusion is reinforced by the fact that the success of mind uploading at securing personal survival might depend on an additional factor, namely the possibility of creating conscious or sentient machines. If, for whatever reason, computers – which, unlike biological brains, rely on hardware rather than “wetware” – happen to fundamentally lack the capacity for consciouness, regardless of how powerful and sophisticated they might be, then uploads turn out to be no more than computer “zombies” mimicking now deceased people. It’s unclear that someone could “survive” as such an entity. And even if we assume that they could, the value of such survival, devoid of the conscious experiences that make our lives worth living, would be dubious, somewhat like the value of surviving with only a brain stem. This point about machine consciousness equally applies to the idea of a “Moravec transfer”, i.e. a procedure involving gradually uploading a person’s mind to a computer (neuron by neuron if necessary), unlike the BPF’s proposed method (Moravec, 1988). Traditional cryonics, by contrast, can succeed at preserving a person regardless of whether or not computers can be conscious.

Hayworth would presumably deny that any such doubts about the possibility of machine consciousness are legitimate. Indeed, he seems to confidently embrace the so-called computational theory of consciousness, according to which consciousness is fundamentally the product of – highly complex – computation, which we know computers to be capable of at least in principle (e.g. Hayworth, 2015). However, there is currently no general agreement among philosophers of mind or neuroscientists that the computational theory of consciousness is correct, and Hayworth does not demonstrate that it is (although he dogmatically equates the idea that there might be physical properties required for the production of conscious experience which are found in wetware, but not computer hardware, with invoking “magic”).

Furthermore, even if taken for granted, the computational theory of consciousness cannot, absent additional philosophical arguments, show mind uploading to be consistent with personal survival. Assuming that R2-D2 from Star Wars is conscious does not commit us to accepting that a perfect replica of R2-D2 built from fresh parts, after – let us assume – it was destroyed by the Empire’s forces, is numerically identical with the original robot. In response, Hayworth could perhaps abandon PsyCon and instead invoke the claim, famously defended by philosopher Derek Parfit, that personal identity does not actually matter in the way many of us tend to think – rather, psychological continuity is what really matters (Parfit, 1984). (In his reply to an article by neuroscientist Michael Hendricks critical of cryonics, Hayworth actually appears to move in that direction: see Hayworth, 2015.) However, besides the fact that this is again a controversial philosophical view, it notably led Parfit to dissociate psychological continuity from personal survival, and to conclude that the latter was, in itself, also overrated. This position is very much at odds with the life extension project, which the BPF claims to be pursuing.

I cannot but see some irony in the fact that Hayworth, the author of an essay titled “Killed by Bad Philosophy”, should show a degree of overconfidence in his philosophical views that might potentially lead his followers to experience the very same outcome his essay is warning against.

The differences previously highlighted between traditional cryonics and the BPF’s approach are summarised in the table below:

If: Traditional cryonics* ASC + mind uploading*
Physical continuity theory is true Survival Death
Psychological continuity theory is true Survival Survival
Machines can’t be conscious Unaffected Compromised (creates computer “zombie”)

(*It is assumed that the relevant procedures are performed in accordance with the highest standards of quality)

WHAT THE CRYONICS MOVEMENT CAN LEARN FROM THE BPF

None of this is meant to imply that the work of the BPF is without merit. On the contrary, the Foundation’s approach demonstrates a number of virtues that can provide a model for the cryonics movement to follow. These include a commitment to rigorously and impartially evaluating the quality of brain preservation procedures, in accordance with the standards of scientific peer-review. Another example is the BPF’s successful effort at crowdfunding its incentive prizes for brain preservation research, such as the two prizes won by 21CM. For those seeking to promote life extension through brain preservation, who I have argued need to prioritize cryonics-specific research, this suggests two main paths worth pursuing in the future:

(a) Incentive prizes. Such prizes are a powerful tool for stimulating research, particularly in neglected areas of science. Unfortunately (and perhaps unsurprisingly, given Hayworth’s philosophical beliefs), the BPF does not at this point appear inclined to set up any new prize that would include a requirement to preserve the brain’s potential for viability. On the basis of the arguments I have provided so far, I submit that the institution of a prize (possibly crowdfunded) incorporating that requirement would be highly desirable.

How demanding such an incentive prize should be with regards to the winning entry is a matter for further debate. A relatively modest version would require demonstrating adequate ultrastructure preservation in a small mammalian brain, but using a procedure that could in principle be reversed by future technology, making it possible for the original brain to eventually be “re-started”. However, based on a recent talk by Dr Greg Fahy from 21CM, which I attended in May 2017 at the International Longevity and Cryopreservation Summit in Madrid, such a goal may soon be achieved. Indeed, Dr Fahy reported having found a way to largely overcome the abovementioned problem of dehydration and shrinking that has so far prevented a proper assessment of the quality of ultrastructure preservation offered by traditional cryonics protocols (e.g. using M22). Assuming Fahy has now reached that milestone (and I look forward to the publication of his paper on the topic), one could set up a prize with a more ambitious goal: for instance, one could add that besides showing good ultrastructure preservation and retaining the preserved brain’s potential for viability, one should also demonstrate actual viability, say via measurable electrical activity, either at the level of the whole brain or in slices obtained from that brain. Ultimately, the details of such a prize should be worked out by scientists with the relevant expertise (as long as the constraints I have outlined here are respected).

Those who believe that ASC holds greater promise could support a prize rewarding the first team who found a way to reverse the fixative process involved in that procedure, and restore the original neural structure.

(b) Research funds. Such a fund, which could also be crowdfunded, would be managed in a transparent manner by an organization committed to promoting cryonics-specific research. In accordance with standard practice when it comes to funding scientific research, project proposals would be solicited from active researchers in cryobiology (and other relevant fields), and a committee of experts would select the proposals that it deemed most worthy of funding. The organization would then help disseminate the results of the completed projects (e.g. as laid out in peer-reviewed publications).

The scientific experts tasked with evaluating the submissions for either an incentive prize or a research fund should ideally be publicly identified, and sufficiently independent of both the authors of the submissions and of cryonics companies (e.g. they should not be receiving research funding from those companies). Furthermore, while an organization that might implement solution a) or b) could be created de novo, existing institutions might already be able to fulfill that role. One example would be the UK Cryonics and Cryopreservation Research Network (http://cryonics-research.org.uk), led by Dr João Pedro de Magalhães, who has connections with other scientific experts, including Ken Hayworth. Despite the scientific rigour with which it approaches the issue of cryonics, the network is currently underfunded.

While most people may understandably not be able to commit substantial amounts of resources to supporting cryonics research, the success that the BPF has enjoyed so far with its incentive prizes demonstrates that large numbers of even small donations can foster impressive technical breakthroughs and help strengthen the credibility of research projects of the most audacious sort. I believe it is now time to apply a similar approach to the safer bet of cryonics-specific research. Further raising the public profile of such research, and improving its status in the eyes of the mainstream scientific community, can help promote a virtuous cycle leading in turn to more funding and greater professionalization. The sooner we can make this happen, the better.

An earlier version of this article appeared in Cryonics magazine, November-December, 2017.

REFERENCES:

DE WOLF, A. August 21 2017. Cryonics Without Cerebral Dehydration? Evidence-Based Cryonics [Online]. Available from: http://www.evidencebasedcryonics.org/2017/08/21/cryonics-without-cerebral-dehydration/.

HAYWORTH, K. 2010. Killed by Bad Philosophy: Why Brain Preservation Followed by Mind Uploading Is a Cure for Death. Available: http://www.brainpreservation.org/content-2/killed-bad-philosophy/.

HAYWORTH, K. September 16 2015. Ken Hayworth’s Personal Response to MIT Technology Review Article. Brain Preservation Foundation [Online]. Available from: http://www.brainpreservation.org/ken-hayworths-personal-response-to-mit-technology-review-article/.

MCINTYRE, R. L. & FAHY, G. M. 2015. Aldehyde-Stabilized Cryopreservation. Cryobiology, 71, 448-58.

MCMAHAN, J. 2002. The Ethics of Killing : Problems at the Margins of Life, Oxford, Oxford University Press.

MORAVEC, H. P. 1988. Mind Children : The Future of Robot and Human Intelligence, Cambridge, Mass., Harvard University Press.

PARFIT, D. 1984. Reasons and Persons, Oxford, Clarendon Press.

THE BRAIN PRESERVATION FOUNDATION. n.d. Overview of 21st Century Medicine’s Cryopreservation for Viability Research [Online]. Available: http://www.brainpreservation.org/21cm-cryopreservation-eval-page/.

THE BRAIN PRESERVATION FOUNDATION. 2018. Aldehyde-Stabilized Cryopreservation Wins Final Phase of Brain Preservation Prize [Online]. Available: http://www.prweb.com/releases/prweb15276833.htm.

New Warming Breakthrough for Cryopreserved Organs?

Although not of immediate concern to cryonics, warming has always been more of a challenge than cooling for cryopreservation by vitrification. This is because the initial formation of ice crystals is most rapid at very low temperature, such as -120°C, but crystal growth is faster at warmer temperatures. Tissue being warmed from the very cold temperatures of vitrification therefore often contains many tiny crystals that are ready to grow during passing through warmer temperatures until the melting point is reached. The warming rate required for successful recovery from vitrification therefore tends to be about ten times faster than the minimum cooling rate.

Since Fahy first proposed vitrification for organ cryopreservation in the 1980s, it was envisioned that a technique called radiofrequency warming (RF warming) would be used to recover organs from vitrification. In RF warming, a rapidly oscillating electric field at a frequency ranging from tens to hundreds of megahertz is applied during warming. The oscillating electric field causes water molecules to vibrate and heat the organ uniformly from the inside similar to a microwave oven. However RF warming uses frequencies much lower than microwave ovens to achieve more uniform heating without “hot spots.” Ruggera and Fahy at the U.S. FDA and American Red Cross published the first paper specifically studying RF warming of vitrified organs in 1990. In the decade that followed, Pegg, Evans and their research group at Cambridge University published numerous papers on technical aspects of RF warming of organs. In 2013 Wowk, Corral and Fahy resumed development of RF warming for recovery of organs from vitrification at 21st Century Medicine, Inc.

In 2014 Etheridge and Bischof et al at the University of Minnesota published a new idea for warming of vitrified organs. Magnetic nanoparticles were to be added to the cryoprotectant solution inside blood vessels, and the nanoparticles warmed by a radiofrequency magnetic field instead of electric field. This new method, called “nanowarming,” received a great deal of publicity in March of this year in connection with a new paper about it in the journal Science Translational Medicine. While having the disadvantage of warming occurring only in blood vessels, which could cause overheating of very large blood vessels, the method has a distinct advantage over classical RF warming. The energy absorption efficiency, and therefore heating efficiency, of classical RF warming varies with viscosity and temperature of tissue. This can be used beneficially to maximize warming rates during the most critical phases of rewarming. However classical RF warming is unavoidably inefficient at very low temperatures, below -100°C.
Nanowarming, in contrast, warms smoothly and efficiently at all temperatures, even the very lowest. Nanowarming may therefore be especially useful for uniform warming through the “glass transition” – the very low temperature at which vitrified organs change from being solid to liquid in their behavior – a critical phase of warming for avoiding thermal stress injuries.

With the development of nanowarming, there are now two independent technologies for achieving the necessary rapid warming of organs from the vitrified state, bringing us closer to an era of transplantable organ banking. The relevance of these technologies to cryonics remains speculative at this stage. In one envisioned resuscitation scenario, repairs of the brain and/or body would be conducted at cryogenic temperatures. It is reasonable to assume that these molecular machines would also introduce novel (ice-blocking) technologies that completely eliminate the risk of ice formation upon re-warming.

Another concern is cost. At this point adding high-quality nanoparticles to the perfusate would be prohibitively expensive.

This column was written with extensive  input from a notable cryobiology researcher.

Originally published as a column in Cryonics magazine, July-August, 2017

Advances in Cryoprotectant Toxicity Research

There is little disagreement among cryobiologists that the biggest limiting factor to reversible organ cryopreservation is cryoprotectant toxicity. It is actually not that hard to create vitrification solutions that completely inhibit ice formation at even the slowest cooling rates. The problem is that such highly concentrated vitrification solutions are too toxic to permit recovery of complex organs. The least toxic vitrification solution for complex mammalian organs as of writing is M22. M22 is the culmination of many years of experimental and theoretical work by cryobiologist Greg Fahy and colleagues.

Studying cryoprotectant mixtures on rabbit kidney slices, Fahy and colleagues came to the following conclusions:

1. High concentrations of a cryoprotective agent (or a mixture of different cryoprotective agents)
can prevent ice formation during cooldown and warming.

2. The toxicity of some cryoprotectants can be neutralized by combining them with other cryoprotectants.

3. The non-specific toxicity of a cryoprotectant solution can be predicted by calculating a quantity (“qv*”) which is intended to measure the average hydrogen-bonding strength of the cryoprotectant polar groups with the water molecules in the solution.

4. Within limits, non-penetrating agents can reduce the exposure of cells to toxic amounts of cryoprotectants without reducing vitrification ability.

5. Synthetic “ice blockers” can be included in a vitrification mixture to reduce the concentration of toxic cryoprotective agents necessary to achieve vitrification.

While M22 is a low toxicity solution, its toxicity profile still necessitates minimizing exposure time and introduction and removal at low (subzero) temperatures. If we had a better understanding of the mechanisms of cryoprotectant toxicity, vitrification solutions with no toxicity at all could be introduced at higher temperatures and exposure times could be increased to optimize complete equilibration of the tissue with the cryoprotectant.

Two major reviews of cryoprotectant toxicity were published in the last 5 years; Gregory Fahy’s“Cryoprotectant Toxicity Neutralization” (Cryobiology, 2010) and Benjamin Best’s “Cryoprotective Toxicity: Facts, Issues, and Questions” (Rejuvenation Research, 2015).

Greg Fahy’s paper is a rigorous exposition of experimental results concerning the phenomenon of cryoprotectant toxicity neutralization. The paper is mostly limited to the discovery that DMSO can block the toxic effects of amides such as formamide. The combination of DMSO and formamide (or other amides such as urea and acetamide) is indeed one of the building blocks of M22 but this combination cannot be used without limit and the paper includes data that indicate the maximum molar concentrations (and ratios) that still permit full viability. In theory, if two (or more) cryoprotectants would completely neutralize each other’s toxicity they could be the sole components of a vitrification solution. But as the formulation of M22 shows, it is still necessary to add weak glass formers such as ethylene glycol, extracellular CPA’s, and “ice blockers” to supplement the toxicity neutralization obtained with formamide and DMSO. An important finding in Fahy’s paper is that n-methylation abolishes toxicity neutralization for amides and combining methylated amides also does not lead to toxicity neutralization between
them. In fact, Fahy found that the presence of n-methylated compounds renders even small amounts of DMSO toxic. The remainder of the paper discusses the mechanisms of cryoprotectant toxicity and Fahy now favors protein denaturation as a plausible mechanism of (non-specific) toxicity. While other cases of toxicity neutralization have been reported in the literature, no rigorous studies have been done to produce a body of knowledge that is comparable to what we know about amide-DMSO interactions.

Benjamin Best’s paper is more general in scope but discusses a lot of experimental data from other papers and also critically discusses Fahy’s work on cryoprotectant toxicity. As Ben Best points out, different (and seemingly contradictory) results do not necessarily mean that cryoprotectant toxicity is a species or cell-type dependent phenomenon. One could imagine a meta-analysis of cryobiology data in which variables such as concentration, loading and unloading protocols, exposure temperature, exposure time, and the type of viability assay are matched to ensure methodological consistency. It is also important to compare cryoprotectants at their minimum concentration to vitrify to make meaningful toxicity comparisons.

If the work at 21st Century Medicine is an indication, universal low-toxicity cryoprotective solutions should be feasible. Perhaps the most interesting part of the paper is where Best offers a critique of Greg Fahy’s “qv* hypothesis of cryoprotectant toxicity,” which aims to show that non-specfic toxicity concerns the degree to which cryoprotectants leave water available to hydrate macromolecules. This discovery allowed for the substitution of ethylene glycol for propylene glycol in Fahy’s lower toxicity vitrification solutions, despite the resulting higher CPA concentrations. Best observes, “it seems contradictory that water remains available for hydration, but not available for ice formation.” A potential rejoinder to this observation is that so called “bound water” does not participate in ice formation but can be disturbed by strong glass formers. Best also suggests a potential refinement of qv* that allows for more precise calculation of the hydrogen bonding strength of the polar groups that are used to calculate qv*. It is conceivable that such a refinement would eliminate the few remaining outliers in the data that support the qv* hypothesis. The paper also draws attention to the possibility of kosmotropic co-solvents and changes of pH and microenvironment polarity to mitigate cryoprotectant toxicity.

Neither of the papers discusses cryopreservation of the mammalian brain, but there is good reason to believe that in the case of this organ, modification of low-toxicity vitrification solutions is required. Conventional cryoprotective agents such as PG, EG, and DMSO have poor blood brain barrier (BBB) penetration and the brain may not tolerate the CPA exposure times that other organs do. For example, while M22 can be used for cryopreservation of the brain, many of its component have poor BBB penetration and PVP and the ice blockers (X-1000 and Z-1000) are assumed not to cross the (non-ischemic) BBB at all. One potential solution is to (reversibly) open the BBB with so-called BBB modifying agents like detergents or perhaps to search for cryoprotective agents that can cross the BBB.

The most fundamental question in the design of vitrification solutions remains whether it is possible at all to introduce high concentrations of cryoprotectants without creating any kind of irreversible molecular and ultrastructural adverse effects. Understanding what specific and nonspecific cryoprotectant toxicity exactly is should enable us to answer this question.

Originally published as a column in Cryonics magazine, August-September, 2016

Scientific Proof for Cryonics?

A cryonics advocate makes an eloquent case for cryonics. Then a scientist is called upon to dismiss the idea of cryonics because there is “no proof” for it. Unfortunately, such a statement reveals that the “scientist” in question does not know the difference between empirical science and logic, and also does not understand the difference between cryonics and suspended animation.

As the evolutionary biologist Satoshi Kanazawa writes in a November 16, 2008 column for Psychology Today “The knowledge that there is no such thing as a scientific proof should give you a very easy way to tell real scientists from hacks and wannabes… Proofs exist only in mathematics and logic, not in science. Mathematics and logic are both closed, self-contained systems of propositions, whereas science is empirical and deals with nature as it exists. The primary criterion and standard of evaluation of scientific theory is evidence, not proof.” He goes on to write that “all scientific knowledge is tentative and provisional, and nothing is final. There is no such thing as final proven knowledge in science.”

What is the proper role of science in cryonics? Let’s say that a person proposes that if we freeze a person after clinical death there is a reasonable expectation that more advanced medical technologies can reverse the freezing damage, the medical condition that gave rise to this person’s critical condition, and also the aging process that caused this medical condition in the first place. We can respond to this proposal by asking a number of questions. What will freezing do to the fine structure of the brain? How will future medical technologies infer the original state of the brain from the frozen state? What kind of technologies are required to repair the brain and restore the person to a healthy and youthful state?

These are the kinds of questions where science (and reasonable extrapolations of where science will be heading) is important in evaluating the idea of cryonics. And we are not limited to just consulting existing science, we can also push science in the direction of minimizing the damage incurred during cryopreservation so the odds of revival for the typical cryonics patient will increase. For example, in 2000 Alcor changed its protocol from limiting freezing to eliminating it through a technology called vitrification. Advances in gene editing, virus modification, and nano-scale 3D printing can make the idea of cell repair more plausible. Advances in science and technology of this nature can make people update their prior (subjective) estimates about the probability of cryonics being successful.

What such advances in science cannot do is to provide “proof ” that cryonics will work. They cannot do this because all scientific knowledge is “tentative and provisional,” but it also cannot do this for a more fundamental reason. Cryonics is not suspended animation. Cryonics concerns
stabilizing people for whom no successful medical treatment is available to permit them to benefit from future advances in medicine. By definition, it is not possible to prove that these technologies will become available.

What people who insist on “proof ” for cryonics want to see is evidence of reversible cryopreservation. Human suspended animation is indeed a research- and clinical objective that a credible cryonics organization should aim for. But it cannot be emphasized enough that while “proof ” of suspended animation would provide strong support for the practice of cryonics is it is not necessary for the cryonics idea to be plausible. What is necessary for cryonics to work is that the brain (and rest of the body) of a person are preserved to a degree that the original, healthy, state of the brain can be inferred from the preserved state. Perhaps future “neurological archeology” technologies will reveal that even freezing of the brain without cryoprotectant allows for complete revival.

A proper understanding of cryonics requires that scientists recognize the difference between providing proof and updating expectations based on empirical evidence. But it also requires the scientist, as the great cryonics writer Thomas Donaldson once recognized, to make peace with the unknown because the capabilities of future science remain a matter of debate and we cannot say for certain when a person is dead by information-theoretic criteria.

Originally published as a column in Cryonics magazine, July-August, 2016

Human Biostasis Options: Advantages and Limitations

On February 9, 2016 the Brain Preservation Foundation announced that the cryobiology company 21st Century Medicine had won their small mammal brain preservation prize. The team at 21st Century Medicine used a procedure named Aldehyde-Stabilized Cryopreservation (ASC) to preserve the ultrastructure of the brain in a “near-perfect” condition. It is important to understand how ASC differs from both conventional cryopreservation and other human biostasis alternatives to understand its merits and limitations.

In conventional cryopreservation (which is the procedure Alcor currently uses) the blood (and cell water) in the brain is replaced with a vitrification agent that permits long term storage at liquid nitrogen temperature without further degradation. The advantage of this method is that it seeks to both preserve viability and the fine ultrastructure of the brain. Currently, the disadvantage of this method is that it produces (severe) cerebral and cellular dehydration, which alters the ultrastructure of the brain and renders some components of the brain difficult to observe in electron micrographs.

A radically different alternative to cryopreservation is to chemically fix the brain with aldehydes (formaldehyde, glutaraldehyde) and store the brain at room temperature or in a fridge in the liquid state. While some people consider such a procedure “better than nothing”, Alcor does not support this kind of “chemopreservation” as a long term care option due to concerns about long-term degradation and  sub-optimal preservation in ischemic cases. An extensive critique of liquid state chemopreservation can be found in my article ‘Chemical Brain Preservation and Human Suspended Animation.’

What is notable about the procedure that won the small mammal brain preservation prize is that it combines both aldehyde fixation and vitrification. In short, first the brain is perfused with glutaraldehyde, followed by perfusion of a high concentration of cryoprotectant to protect the brain against ice formation during long term care. This idea is actually not new and was discussed in in the mid-1980s in Eric Drexler’s book Engines of Creation. The renewed popularity
and technological development of this idea was recently triggered by the formation of the Brain Preservation Foundation and its emphasis on ultrastructural preservation. The protocol that won the small mammal brain cryopreservation prize has shown indeed a degree of ultrastructural preservation that has not yet been achieved with conventional brain cryopreservation.

Alcor’s biggest concern with aldehyde-stabilized cryopreservation is that it renders the tissue completely dead by contemporary viability criteria by creating irreversible crosslinks between bio-molecules. Despite claims to preserve the “connectome”, at the molecular level structure is fundamentally altered. In terms of research aimed at reversible biopreservation, this is a dead end.

Conventional cryo, conventional chemo, and a combination of the two are the three most discussed options of human biopreservation. Other, hypothetical possibilities include (a) vitrification with agents with much higher glass transition temperatures that permit warmer storage such as at dry ice temperature (b) poly-vitrification, in which high molecular weight polymers are used to stabilize the patient near or at room temperature, and (c) the use of molecular nanobots to induce reversible biostasis (an idea originally proposed by Robert Freitas).

The current position of Alcor is to keep researching and offering conventional cryopreservation without the use of chemical fixatives. The research emphasis of the organization and associated labs this year will be to produce better electron micrographs of cryopreserved brains and the validation of blood brain barrier modifying agents to eliminate the severe dehydration that is currently observed in “good” cryonics cases.

Originally published as a column in Cryonics magazine, March-April, 2016

Cryonics is not Mind Uploading

On September 15, 2015, the MIT Technology Review published an article named “The False Science of Cryonics” that revealed how much ignorance about cryonics still exists among those that should know better (scientists, medical professionals, etc.). First of all, cryonics is not a “science” but an experimental medical procedure that is informed by scientific developments in disciplines such as cryobiology and neuroscience.

Semantics aside, a major flaw in the article is that it conflates mind uploading and cryonics. While some of our members may favor the possibility of “substrate-independent minds,” in its most “conservative” incarnation resuscitation will occur through repair of the same biological brain (or whole body) that was preserved. Complicated philosophical issues about whether a copy is “you” do not come into play in this repair scenario at all. So when Alcor was asked by a reporter to comment on the article, we submitted the following response:

The article in the MIT Technology Review rests on several mistaken assumptions. First of all, cryonics does not require or imply mind uploading. While some of our individual members are interested in this topic, the default resuscitation scenario for cryonics patients involves molecular repair of the patient’s biological brain (and body). While we are encouraged by the rise of connectomics, the aim at Alcor is to cryopreserve all the fine details of the brain and even secure viability of the brain as well as we can. In fact, in our stabilization procedures we aim to keep the brain viable by contemporary medical criteria and collect data to evaluate the efficacy of our procedures.

Alcor is a charitable, non-profit, organization and we do not make a profit when we place our patients in biostasis. Also helpful to understanding the ethics and financial feasibility of cryonics for persons of ordinary means is that most people fund cryonics through an affordable, dedicated, life insurance policy, making cryonics an accessible personal choice.

We strongly disagree that without proof of human suspended animation or flawless ultrastructural preservation it is not ethical to practice cryonics. Our organization challenges the mainstream definitions of death, and we believe that perfected cryopreservation is a sufficient but not necessary condition for cryonics to succeed. As long as we have good reasons to believe that the original state of the brain can be inferred from the damaged state, making cryonics arrangements can be a rational choice to make. To our knowledge, there are no rigorous, scientific, studies that demonstrate that today’s cryonics procedures produce irreversible destruction of identity-critical information.

Information about the ultrastructural effects of the vitrification solutions we use to inhibit ice formation can be found here: http://www.alcor.org/Library/html/newtechnology.html

It is disappointing that scientists and professional writers put so little effort into understanding what cryonics entails and what the real technological challenges are. Unfortunately, there is essentially no cost to being factually wrong about cryonics. In fact, when professional cryobiologists comment on cryonics they often make claims about their own field that are factually incorrect, such as that cryonics produces intracellular freezing, or that ice-free cryopreservation of complex organs is not yet possible.

We may not be able to persuade everyone that cryonics is the prudent, conservative choice to make, but we might benefit from giving more thought to how to prevent and counter factually erroneous articles such as the one in the MIT Technology Review.

Originally published as a column in Cryonics magazine, November 2015

How to Validate New Cryonics Technologies

Evidence in cryonics is a complicated concept. For starters, it is not possible to “prove” cryonics will work, here and now, because the fundamental idea of cryonics is to stabilize critically ill patients (people considered “dead” by less rigorous criteria) in anticipation of more advanced future medical technologies. What we can do is validate cryonics technologies with reversible cryopreservation (“suspended animation”) as a benchmark. As a general rule, we can state that we make progress in cryonics when stabilization, cryopreservation, and maintenance (“storage”) technologies cause less damage than the technologies that preceded them. But how do we know if this is the case?

The most rigorous form of validation, human clinical trials, is usually not available in cryonics. There are often new (approved) emergency medical technologies, however, that can be modified to be used in cryonics procedures. A major advantage of adopting such technologies is that the validation has already been done by other organizations or companies. Examples of such technologies will often fall under the rubric of emergency medicine. For example, an FDA-approved technology that improves blood flow during cardiopulmonary resuscitation can be added to Alcor’s stabilization equipment to improve stabilization procedures.

One step down from rigorously designed human clinical trials are animal studies. In cryonics we often make a distinction between small animal studies (e.g., mice, rats) and large animal studies (e.g., pigs, dogs) etc. It seems common sense to think that large mammals provide stronger evidence for a technology than smaller animals but the real issue at stake here is not how large an animal is but how closely an animal model tracks what happens in humans. For example, if cat brains have an uncharacteristically high tolerance for cerebral ischemia, the (smaller) rat may actually be a more realistic model for validating neuroprotective strategies in humans.

One area where choosing the correct animal model has proven itself to be of crucial importance concerns the effect of cryoprotectants on the brain. Most mammalian species experience dehydration of the brain after equilibration with a vitrification agent. Because it is reasonable to assume that severe dehydration adversely affects brain viability it is tempting to select an animal model that experiences little cryoprotectant-induced dehydration. But one thing that we have learned from burhole measurements and CT scans in human cryonics patients is that under optimal conditions cryoprotective perfusion with both glycerol and the modern vitrification agents produces severe shrinkage of the brain. So if we want to validate strategies to eliminate this dehydration the most important consideration is not how “large” the animal is but how well the animal tracks the effects of cryoprotectants on the human brain.

Most technologies in cryonics need to be evaluated with ultrastructure and/or viability as an endpoint. But there are also new developments in cryonics where such a benchmark would not make a lot of sense. For example, if we build a new patient enclosure to keep the patient cold during cryoprotective perfusion we can just measure the core temperature of the patient to see if we have done a satisfactory engineering job. Another example is the design of new dewars where we can look at variables like the boiloff rate and long-term durability of the design.

In conclusion, there are a number of ways to validate new technologies in cryonics. If a new technology has undergone human clinical trials we often can just adapt that technology for cryonics without designing new experiments. In the case of more cryonics-specific technologies animal studies can be conducted and the choice of animal model will be dictated by how close a model tracks what we know to occur in humans (among other considerations like ethics and cost). Finally, when a new development in cryonics is mostly an engineering challenge, validating its efficacy is often just an issue of doing basic physiological measurements or practical tests.

Originally published as a column in Cryonics magazine, August, 2014

Who Decides What We Can Do With Our Body (and Brain)?

Statement on the High Court ruling concerning 14 year-old cancer victim’s right to cryonics

Click here for PDF

Our hearts go out to the young British woman whose battle with cancer ended sadly earlier this month at age 14, as well as to her parents as they cope with this very difficult time. And we commend the British High Court Judge for his important ruling enabling the girl to obtain her wish to be cryogenically preserved. While we have no comment on the specifics of this case, and do not ourselves offer services of this nature, we hope we can shed some light on the project of experimental medical biostasis / cryonics more generally.

Over the past decade, scientists have made significant advances in low-temperature biology, and scientists developing molecular machines will receive this year’s Nobel Prize on December 10. Many, including scientists at places like Cambridge, Oxford, MIT, NASA and Harvard, now openly support cryonics as a legitimate scientific endeavor. Of course there is no guarantee that any cryonics patients will be revived in the future, but as discussed by four tenured professors in this recent MIT Technology Review piece, the best evidence suggests that cryonics deserves open-minded consideration.

Coordinator of the UK Cryonics and Cryopreservation Research Network, Dr João Pedro de Magalhães, when asked for his thoughts, observed that “no matter the probability you assign to the procedure, we think it’s important to give people the choice, just as we give dying patients the opportunity to try other experimental medical therapies to save their lives”.

Cryonics is a similar experimental treatment, albeit one with different legal and ethical implications, and whose probability of success is unknown. Many parts of the world are now taking progressive stances towards the idea of death with dignity. It seems incongruous with these beliefs to stigmatize a procedure for what is at worst an over-optimistic belief about the state of the future.

Despite the many intermediate successes in low-temperature biology over the past few decades, no cryonics organization can currently revive a patient. Nobody has claimed otherwise, and arguments based on this premise are missing the point.

Cryonicists look at how medicine has progressed over the past hundred years, at the millions of people whose lives would have been cut short if not for advances in technology, and it fills them with hope about what might be possible for the future. The goal of cryonics is not to be able to revive someone with contemporary technology, rather the goal is to preserve a person and her brain well enough that future technologies may be able to (repair and) revive the person. One can think of this as transporting the body forward through time or as medical time travel. This depends on technologies that will be developed in the next decades or centuries, not on the world’s capabilities today. All the major cryonics organizations in the western world are non-profits with the goal of surviving for centuries.

As Aschwin de Wolf, President of The Institute for Evidence-Based Cryonics, explained, “Cryonics is based on the premise that the neuro-anatomical basis of identity is more robust than folk wisdom suggests, and we envision future technologies that can infer the healthy state of the brain from the injured state – and even repair any damage that occurs during the cryopreservation process itself. As such, cryonics is not an act of faith, but an act of reason.”

We will cure cancer one day, and it is reasonable for this girl, born too early through no fault of her own, to choose for herself the best chance to make it to that world where more is possible.

Contact / interviews:

Dr João Pedro de Magalhães

Coordinator, UK Cryonics and Cryopreservation Research Network

+44 151 7954517 / aging@liverpool.ac.uk

www.cryonics-research.org.uk

Aschwin de Wolf

President, Institute for Evidence-Based Cryonics

contact@evidencebasedcryonics.org

www.evidencebasedcryonics.org

Appendix of key supporting materials

  • “The patient should participate responsibly in the care, including giving informed consent or refusal to care as the case might be…The patient’s right is based on the philosophical concept of respect for autonomy, the common-law right of self-determinationAmerican College of Physicians Ethics Manual, 2016

The Multi-Headed Hydra

This article explores some of the regulatory challenges facing those who would bring rejuvenation biotechnologies, like those pursued by Dr. Aubrey de Grey and the SENS Foundation, to market. It does not presume familiarity with Dr. de Grey and his work; I’ve tried to make it informative to all alike.

The Conquest of Aging

Biomedical gerontologist Aubrey de Grey predicts that the first human being to live to 1,000 years old is alive today. Who exactly that person might be – or rather, how old they are today – is a detail that Dr. de Grey has wavered on, but he has remained firm in his commitment to that prediction, and is certainly one of the most prominent figures working towards realization of the technologies required to make his prophecy reality. In his book, Ending Aging, Dr. de Grey describes his proposed approach to the “problem” of aging, and how it differs from those presently in practice.[1]

In Dr. de Grey’s opinion, the current paradigm devotes a vast majority of resources to geriatric care, which attempts to cure or manage age-associated diseases only after they emerge as recognizable groupings of symptoms. To quote an apt metaphor from another longevity advocate:

“[T]he challenge of treating illnesses in the elderly must at times seem like Heracles’ trials of combating the multi-headed Hydra. Each time one head was severed, two more would sprout in its place. Likewise, a patient might survive a serious cardiac episode with help of antihypertensive drugs only to succumb to cancer and dementia.”[2] [emphasis in original]

Meanwhile, the (significantly smaller) remaining portion of research dollars goes towards biogerontology, which studies the upstream causes of aging, any benefit of which is probably unrealizable for several human generations. However, Dr. de Grey argues that without necessarily knowing much more about the upstream causes of aging than is currently understood, it is already possible to categorize the different forms of aging “damage,” and devise therapies that will repair the damage at a sufficient rate to achieve what he terms “longevity escape velocity.”

Dr. de Grey calls his theory “Strategies for Engineered Negligible Senescence” (SENS). There are seven strategies, each related to one of the seven major categories of aging damage thus far discovered. Those categories (and proposed therapies) are: (1) cancer-causing nuclear mutations (removal of telomere-lengthening machinery, aka OncoSENS); (2) mitochondrial mutations (allotopic expression of 13 proteins, aka MitoSENS); (3) intracellular junk (novel lysosomal hydrolases, aka LysoSENS); (4) extracellular junk (immunotherapeutic clearance, aka AmyloSENS); (5) cell loss & tissue atrophy (stem cells and tissue engineering, aka RepleniSENS); (6) cell senescence (targeted ablation, aka ApoptoSENS); and (7) extracellular crosslinks (AGE-breaking molecules and tissue engineering, aka GlycoSENS). The SENS Foundation was established in 2009, helped in part through seed funding provided by Peter Thiel, co-founder of PayPal and a managing partner of The Founders Fund. The SENS Foundation’s stated purpose is “to research, develop and promote comprehensive regenerative medicine solutions for the diseases and disabilities of aging.”[3]

Delving into the details of each of Dr. de Grey’s proposed strategies is beyond the scope of this article, but it is worth taking a closer look at one of the seven. LysoSENS aims at “junk” molecules which cannot be broken down by human lysosomal enzymes. Over time, these molecules accumulate within cells, contributing to conditions like macular degeneration, atherosclerosis, and Alzheimer’s disease (AD)[4]. Dr. de Grey’s proposition is to search for novel lysosomal enzymes (novel to humans, that is) in bacteria, molds, and other microbes that are involved in “recycling” dead animal bodies, since the “junk” inside our cells is — along with the  rest of us — food to them. SENS research being carried out at Rice University has already identified one such enzyme that, when targeted to the lysosome, decreases cytotoxicity of 7-ketocholesterol (7KC), an oxysterol associated with atherosclerosis and Alzheimer’s disease.[5] Enzyme replacement therapy is already used for the treatment of lysosomal storage diseases not associated with aging, like Gaucher’s disease. Insofar as it could be used to treat a condition (or conditions) remedially, a therapy targeting 7KC with a novel lysosomal enzyme might otherwise resemble traditional approaches to disease treatment, but it could also be used preventively. Other SENS pose even greater challenges to the traditional distinctions between cure, prevention and enhancement. The objective of MitoSENS, for instance, is to render the recipient immune to the fallout consequences of mitochondrial DNA mutations by placing backup copies of the thirteen mitochondrial genes — which naturally reside only inside the mitochondria — into the cell nuclei. Significant research progress is being made into this strategy as well.[6]

The problem of normative definitions of aging

Dowsing for fountains of youth is well and good, but won’t get us very far unless they can be tapped and piped to the marketplace, and while there are many scientific obstacles to overcome before rejuvenation biotechnologies are realized, there are also social, political and legal ones. Many of these problems are definitional. For one, what exactly distinguishes age-associated diseases and conditions from “normal” features of aging? In the words of one scholar: “[F]rom the perspective of modern biogerontology, there is little to distinguish biological ageing from a disease state…. To argue that ageing is not a disease by virtue of its universality is as misleading as it is to argue that the Basenji is not a dog because it does not bark.”[7] But to dismiss this debate as purely semantic or philosophical would be to misunderstand the true difficulty the definitional problem poses.

The U.S. Food, Drug and Cosmetic Act defines “drug” as, inter alia, “articles intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease in man or other animals” and “articles (other than food) intended to affect the structure or any function of the body of man or other animals.” [8] So far so good, because even if the U.S. Food and Drug Administration (“FDA”) did not agree that a particular undesired physical state was a “disease” for the purposes of the first definition, it would be difficult to deny that a proposed therapeutic (whether a chemical entity or a biological product[9]) was not intended to affect the structure or functioning of the body, at some level. However, present regulatory approval pathways indirectly require that a drug be “indicated for the treatment, prevention, mitigation, cure, or diagnosis of a recognized disease or condition or of a manifestation of a recognized disease or condition, or for the relief of symptoms associated with a recognized disease or condition.”[10] [emphasis mine]. The phrase “recognized disease or condition” is not defined in this context[11], and the FDA is not itself the recognizer, but rather looks for consensus within the clinical and/or scientific communities regarding the existence of a particular disease or condition, and of clear criteria for clinical diagnosis thereof.[12] To quote one author: “To the extent that many problems of ageing have not been formally recognized by any of these processes, the FDA has no clear guidance on how to determine if a proposed indication would be acceptable.” [13]

For many age-associated conditions, the question of “recognition” is a valueladen debate. While some commentators will no doubt accuse longevity advocates of “disease-mongering”[14], Dr. de Grey would probably argue that that sort of reaction is a symptom of what he terms the “pro-aging trance”[15] — a terror management strategy that accepts and embraces the apparently unavoidable progressive wasting of one’s body (and mind), instead of rejecting and resisting it. But the cognitively dissonant distinction between normal, “healthy” aging on the one hand, and “diseases” of aging on the other is not impermeable. For some historical perspective, it is worth considering the example of Alzheimer’s disease. When it was first described in 1910, AD only included what is now referred to as “earlyonset Alzheimer’s disease,” i.e., when the symptoms of “senile dementia” appeared in someone under 65.[16] Due to its vastly less frequent incidence, this “presenile dementia” was assumed to be distinct from the normal variety. However this normal/ abnormal categorization broke down in 1977, due to professional recognition of their near identical symptomologies, making the early-onset subtype by far the minority of AD incidence.[17]

A present-day example of this process of recognizing “normal” features of aging as diseases or conditions of aging, is the case of sarcopenia. Sarcopenia (literally “poverty of the flesh”) describes the degeneration of skeletal muscle mass and strength that occurs with aging that contributes (in part) to disability, frailty, and morbidity in older persons.[18] Until fairly recently, sarcopenia and related conditions like sarcopenic obesity were considered “normal” aspects of aging, much like senile dementia prior to 1977. To be fair, both sarcopenia and senile dementia are normal, insofar as they are common conditions in older persons — but that does not mean they are untreatable, nor that they should be left untreated. A number of potential drug targets have been identified that may be of use in treating sarcopenia[19], but if consensus recognition of the condition is lacking there may not yet be a regulatory pathway for licensing therapeutics to treat it.[20]

Thus, as it stands, forging a regulatory pathway for treatments of a common, disabling (and in some cases indirectly lethal) feature of aging involves two distinct steps: first, persuade the scientific and clinical communities that a particular symptomology of aging can and should be treated, and second, persuade the FDA that everyone else is persuaded. But this is not insurmountable. The European Working Group on Sarcopenia in Older People published a “practical clinical definition and consensus diagnostic criteria for agerelated sarcopenia” in 2010[21], which was followed by a consensus definition from The International Working Group on Sarcopenia in 2011[22]. In the U.S., the Foundation for the National Institutes of Health, the National Institute on Aging, and the FDA held a Sarcopenia Consensus Summit on May 8-11, 2012.[23] A number of clinically meaningful end points have been proposed for assessing treatment efficacy[24], including patient-reported outcomes.[25] Under appropriate regulatory supervision, medicalization of sarcopenia would help older persons maintain or even regain functional independence and quality of life — and perhaps boost lifespan, via a reduction in comorbidity with diseases like osteoporosis.

The problem of causally interrelated disease states

There is another definitional problem: What distinguishes one age-associated disease from another? This may seem like a facetious question, given the obvious symptomatic differences between atherosclerosis and AD. However, as mentioned above, the oxysterol 7KC has been implicated in the pathogenesis of both those disease states. If 7KC is indeed a metabolic byproduct that is causally related to both atherosclerosis and AD then, in addition to being a promising drug target itself, it could conceivably qualify as a surrogate endpoint for clinical trials of new drugs indicated for those diseases. FDA has issued a draft guidance regarding qualification of biomarkers as drug development tools[26], but surrogate endpoints may only be used in lieu of direct measures of clinical benefit under the FDA’s “Fast-Track Program,” which is only available for new drugs intended for the treatment of a serious or lifethreatening condition and that demonstrate the potential to address unmet medical needs for such a condition.[27] However, it would not be necessary to qualify 7KC reduction as a surrogate endpoint for both AD and atherosclerosis. Doing so for one or the other based on which is thought to be the more serious condition and/or the greater unmet need would allow its use in a fast-tracked New Drug Application for the one indication, and then if safety and efficacy in humans is established and the therapeutic is approved, data from (likely compulsory) post-marketing studies could be used in a new indication claim for the other condition.

Surrogate endpoints need only be “reasonably likely to predict clinical benefit”[28], and some commentators have pointed out that applying this lower standard to the screening of surrogate endpoints may result in drugs approved on the basis of evidence of an effect on a biomarker which, while related to the disease, is not actually causally related to any clinical benefit.[29] Of course, given its ambitious objective, the SENS Foundation has a strong vested interest in tying 7KC to clinical benefit, and the fact that FDA-qualified biomarkers are released into the public domain also fits within the Foundation’s public interest mandate, and could enhance perceptions of the legitimacy of its research goals. But more importantly, it could shorten clinical trials, an oft-criticized source of delay and drug costs. While its work to date has primarily been proof-of-concept research, in the future the SENS Foundation might devote some of its resources to running forms of aging damage like 7KC through the biomarker qualification process. Although publishing both the proof-of-concept and such valuable drug development tools might cut out some of the traditional patenting opportunities[30], it also offsets costs ordinarily borne by pharmaceutical companies. A little low-hanging fruit might stir up some productive competition in an industry sometimes criticized for chasing after minor therapeutic improvements and patent trolling.

Another option that is very in line with the social agenda of longevity advocates would be to promote the rebranding of multiple disease states with significantly overlapping low-level chemistry as single unified conditions that present varied symptom groupings based on exposure to particular environmental factors (including the endogenous “environment,” like certain genes or epigenetic variations, along with more traditional exogenous contributors like diet, exercise, etc). Admittedly, this would be the more difficult path, because it relies on the two-step process of disease recognition, discussed above, and considering how long it took AD and senile dementia to be folded into AD with an early-onset subtype, trying to replicate this process with diseases that present as differently as atherosclerosis and AD may be a Sisyphean task. On the other hand, academic pressure of this kind could have trickle-out effects on the public, re-situating the discourse of age-associated diseases further upstream, pressing on towards greater recognition of aging as disease.

Finally, slight augmentations to the SENS branding could be in order. Dr. de Grey gave unique names to his proposed strategies (LysoSENS, MitoSENS, etc.), but not to the categories of damage which are the targets of those strategies. Devising and promoting novel medical names for these categories of damage, like idiocytotoxicosis[31] for the “intracellular junk” targeted by LysoSENS, might prompt frame-shifting in the academic and clinical communities that could consequently (albeit indirectly, and thus probably slowly) broaden the scope of “recognized disease or condition”. Sadly for the planet, ‘junk’ doesn’t seem to be something humans take terribly seriously — idiocytotoxicosis, on the other hand, well that’s clearly a monster. Perhaps this suggestion borders on “disease-mongering” — but isn’t that term itself equally agenda-driven, given the not-so-subtle association with war-mongering? Dr. de Grey and other longevity advocates consider themselves to be on moral high ground, so these kinds of accusations are only of consequence if they provoke counter-productive public response, and reframing well-recognized diseases like AD and atherosclerosis as symptoms of underlying “metabolic pathology” can hardly be characterized as “questionable new diagnoses — like [premenstrual dysphoric dysfunction] and social anxiety disorder — which are hard to distinguish from normal life,” the likes of which give at least one critic concern. [32] And perhaps it is the very idea that “normal” is the ultimate objective — as opposed to simply “better” — that is the problem.

What’s the alternative?

If the perceived burden is too high, and the cost of doing nothing too great, stakeholders may look to circumvent the FDA. The SENS Foundation characterizes the assault on aging as the next space race.If the U.S. doesn’t take action to foster local development of what will assuredly be highly sought-after therapies, the movement may simply move underground (i.e. further in the vein of DIYbio), and overseas (medical tourism, and seasteads), which will only hamper the FDA’s mandate to protect Americans from harm.

Endnotes

[1]: Aubrey de Grey & Michael Rae, Ending Aging: The Rejuvenation Breakthroughs That Could Reverse Human Aging in Our Lifetime, (New York: St Martin’s Press, 2007).

[2]: David Gems, “Tragedy and delight: the ethics of decelerated aging” (2011) 366 Philosophical Transactions of the Royal Society B [Phil Trans R Soc B] 108 at 110.

[3]: SENS Foundation, SENS Foundation, online: <http://www.sens.org/about-thefoundation>.

[4]: Jacques M Mathieu et al, “7-Ketocholesterol Catabolism by Rhodococcus jostii RHA1” (2010) 76:1 Applied and Environmental Microbiology 352.

5]: Jacques M Mathieu et al, “Increased resistance to oxysterol cytotoxicity in fibroblasts transfected with a lysosomally targeted Chromobacterium oxidase” (2012) Biotechnology and Bioengineering, online:
<http://www.wileyonlinelibrary.com> DOI 10.1002/bit.24506.

[6]: SENS Foundation, Research Report 2011, online: <http://images.sens.org/reports/ SENS%20Research%20Report%202011.pdf>.

[7]: Supra note 2 at 109.

[8]: 21 USC § 321(g)(1).

[9]: 42 USC § 262(i). The phrase “analogous product” has been used to justify the extension of the FDA’s regulatory authority to human cells, tissues, and cellular and tissue-based products (HCT/Ps). See also Areta L Kupchyk, “Approval of Products for Human Use” in HB Wellons et al, Biotechnology and the Law (ABA, 2007) 591 at 617, note 41

[10]: 21 CFR § 201.57(c)(2) Specifically, this is a labeling requirement, but if a drug cannot be labeled according to the regulation, the New Drug Application cannot be approved. See also 21 CFR § 201.56.

[11]: The term disease is defined in 21 CFR §101.93(g) for the purposes of disease claims relating to dietary supplements, but that is only applicable in that context. See also 21 USC 343(r)(6).

[12]: William J Evans, “Drug discovery and development for ageing: opportunities and challenges” (2011) 366 Phil Trans R Soc B 113 at 114.

[13]: Ibid at 114.

[14]: Barbara Mintzes, “Disease Mongering in Drug Promotion: Do Governments Have a Regulatory Role?” (2006) 3:4 PLoS Medicine e198.

[15]: Aubrey de Grey, “Combating the Tihtonus Error: What Works?” (2008), 11:4 Rejuvenation Research 713.

[16]: GE Berrios, “Alzheimer’s disease: a conceptual history” (1990) 5:6 International Journal of Geriatric Psychiatry 355.

[17]: Robert Katzman et al, Alzheimer’s disease: senile dementia and related disorders (NY: Raven Press, 1978) at 595.

[18]: Eric P Brass & Kathy E Sietsema, “Considerations in the Development of Drugs to Treat Sarcopenia” (2011) 59:3 Journal of the American Geriatrics Society 530.

[19]: Ibid at 531.

[20]: Supra note 12 at 116.

[21]: Alfonso J Cruz-Jentoft et al, “Sarcopenia: European consensus on definition and diagnosis” (2010) 39:4 Age and Ageing 412 (Abstract).

[22]: Roger A Fielding et al, “Sarcopenia: An Undiagnosed Condition in Older Adults. Current Consensus Definition: Prevalence, Etiology, and Consequences” (2011)12:4 Journal of the American Medical Doctors Association [JAMDA] 249 (Abstract).

[23]: See Marco Brotto, “Lessons from the FNIH-NIA-FDA sarcopenia consensus summit” (2012) 9 IBMS BoneKEy 210.

[24]: Supra note 18 at 531-533.

[25]: Ibid at 533. See also Christopher J Evans et al, “Development of a New Patient-Reported Outcome Measure in Sarcopenia” (2011) 12:3 JAMDA 226.

[26]: Center for Drug Evaluation and Research, “Guidance for Industry – Qualification Process for Drug Development Tools,” FDA (October 2010) online: <http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/UCM230597.pdf>.

[27]: 21 USC § 356(a)(1).

[28]: 21 CFR § 314.510.

[29]: Thomas R Fleming, “Surrogate Endpoints And FDA’s Accelerated Approval Process” (2005) 24:1 Health Affairs 67. See also Thomas R Fleming and David L DeMets, “Surrogate end points in clinical trials: are we being misled?” (1996) 125:7 Annals of Internal Medicine 605.

[30]: There may be other intellectual property issues implicated in this shift of paradigm in drug development and regulation, but they are beyond the scope of this article.

[31]: Meaning “self, one’s own” + “cell” + “toxin” + “condition of increase”.

[32]: Supra note 14 at 0463.

[33]: SENS Foundation, Annual Report 2011, online: <http://www.sens.org/sites/ srf.org/files/SENS%20Foundation%20 Annual%20Report%202011.pdf>.

First published as a regular column called In Perpetuity in Cryonics Magazine, March 2013

Advances in Cryoprotectant Toxicity Research

There is little disagreement among cryobiologists that the biggest limiting factor to reversible organ cryopreservation is cryoprotectant toxicity. It is actually not that hard to create vitrification solutions that completely inhibit ice formation at even the slowest cooling rates. The problem is that such highly concentrated vitrification solutions are too toxic to permit recovery of complex tissues. The least toxic vitrification solution for complex mammalian organs as of writing is M22. M22 is the culmination of many years of experimental and theoretical work by cryobiologist Greg Fahy and colleagues using rabbit kidney slices. Studying selected cryoprotectant mixtures on rabbit kidney slices, Fahy and colleagues came to the following conclusions:

1. High concentrations of a cryoprotective agent (or a mixture of different cryoprotective agents) can prevent ice formation during cooldown and warming.

2. The toxicity of some cryoprotectants can be neutralized by combining them with other cryoprotective agents.

3. The non-specific toxicity of a  cryoprotectant solution can be predicted by calculating a quantity (“qv*”) which is intended to measure the average hydrogen-bonding strength of the cryoprotectant polar groups with the water molecules in the solution.

4. Within limits, non-penetrating agents can reduce the exposure of cells to toxic amounts of cryoprotectants without reducing vitrification ability.

5. Synthetic “ice blockers” can be included in a vitrification mixture to reduce the concentration of toxic cryoprotective agents necessary to achieve vitrification.

While M22 is a low toxicity solution, its toxicity profile still necessitates minimizing exposure time and introduction and removal at low (subzero) temperatures. If we had a better understanding of the mechanisms of cryoprotectant toxicity, vitrification solutions with no toxicity at all could be introduced at higher temperatures and exposure times could be increased to optimize complete equilibration of the tissue with the cryoprotectant. It would also allow safer storage at intermediate temperature temperatures (around -130 degrees Celsius) because ultra-stable vitrification solutions could be used that are less prone to de-vitrification upon re-warming. This would be of particular interest for the cryopreservation of large organs or even whole organisms (with applications such as suspended animation and cryonics).

Two major reviews of cryoprotectant toxicity were published in the last 5 years; Gregory Fahy’s “Cryoprotectant Toxicity Neutralization” (Cryobiology, 2010) and Benjamin Best’s “Cryoprotective Toxicity: Facts, Issues, and Questions” (Rejuvenation Research, 2015).

Greg Fahy’s paper is a rigorous exposition of experimental results concerning the phenomenon of cryoprotectant toxicity neutralization. The paper is mostly limited to the discovery that DMSO can block the toxic effects of amides such as formamide. The combination of DMSO and formamide (or other amides such as urea and acetamide) is indeed one of the building blocks of M22 but this combination cannot be used without limit and the paper includes data that indicate the maximum molar concentrations (and ratios) that still permit full viability. In theory, if two (or more) cryoprotectants would completely neutralize each other’s toxicity they could be the sole components of a vitrification solution. But as the formulation of M22 shows, it is still necessary to add weak glass formers such as ethylene glycol, extracellular CPA’s, and “ice blockers” to supplement the toxicity neutralization obtained with formamide and DMSO. An important finding in Fahy’s paper is that n-methylation abolishes toxicity neutralization for amides and combining methylated amides also does not lead to toxicity neutralization between them. In fact, Fahy found that the presence of n-methylated compounds renders even small amounts of DMSO toxic. The remainder of the paper discusses the mechanisms of cryoprotectant toxicity and Fahy now favors protein denaturation as a plausible mechanism of (non-specific) toxicity. While other cases of toxicity neutralization have been reported in the literature, no rigorous studies have been done to produce a body of knowledge that is comparible to what we know about amide-DMSO interactions.

Benjamin Best’s paper is more general in scope but presents a lot of experimental data and also critically discusses Fahy’s work on cryoprotectant toxicity. As Ben Best points out, different (and seemingly contradictory) results do not necessarily mean that cryoprotectant toxicity is a species or cell-type dependent phenomenon. One could imagine a meta-analysis of cryobiology data in which variables such as concentration, loading- and unloading protocols, exposure temperature, exposure time, and the type of viability assay are matched to ensure methodological consistency. It is also important to compare cryoprotectants at their minimum concentration to vitrify to make meaningful toxicity comparisons. If the work at 21st Century Medicine is an indication, universal low-toxicity cryoprotective solutions should be feasible. Perhaps the most interesting part of the paper is where Best offers a critique of Grag Fahy’s “qv* hypothesis of cryoprotectant toxicity”, which aims to show that non-specfic toxicity concerns the degree to which cryoprotectants leave water available to hydrate macromolecules. This discovery allowed for the substitution of ethylene glycol for propylene glycol in Fahy’s lower toxicity vitrification solutions, despite the resulting higher CPA concentrations. Best observes, “it seems contradictory that water remains available for hydration, but not available for ice formation.” A potential rejoinder to this observation is that so called “bound water” does not participate in ice formation but can be disturbed by strong glass formers. Best also suggests a potential refinement of qv* that allows for more precise calculation of the hydrogen bonding strength of the polar groups that are used to calculate qv*. It is conceivable that such a refinement would eliminate the few remaining outliers in the data that support the qv* hypothesis. The paper also draws attention to the possibility of kosmotropic co-solvents and changes of pH and microenvironment polarity to mitigate cryoprotectant toxicity.

Neither of the papers discusses cryopreservation of the mammalian brain, but there is good reason to believe that in the case of this organ modification of low-toxicity vitrification solutions is required. Conventional cryoprotective agents such as PG, EG, and DMSO have poor blood brain barrier (BBB) penetration and the brain may not tolerate the CPA exposure times that other organs do. For example, while M22 can be used for cryopreservation of the brain, many of its component have poor BBB penetration and PVP and the ice blockers (X-1000 and Z-1000) are assumed not to cross the (non-ischemic) BBB at all. One potential solution is to (reversibly) open the BBB with so- called BBB modifying agents like detergents or perhaps to search for cryoprotective agents that can cross the BBB.

The most fundamental question in the design of vitrification solutions remains whether it is possible at all to introduce high concentrations of cryoprotectants without creating any kind of irreversible molecular and ultrastructural adverse effects. Understanding what specific and non-specific cryoprotectant toxicity exactly is should enable us to answer this question.

Originally published as a column (Quod incepimus conficiemus) in Cryonics magazine, September-October, 2016