In praise of cold

14. January 2013 · Comments Off · Categories: Cryonics, Neuroscience, Science

Some observers believe that cryonics advocates are reluctant to subject their theories to experimental scrutiny because this could damage their (uncritical) belief in future resuscitation. Similarly, one might think that cryonicists would react with a mix of hostility and dismissal to alternative strategies for personal survival. Nothing could be further from the truth. In fact, it is exactly because our personal survival is at stake that forces us to be wary of dogmatism.

For this reason, I have always been interested in chemical fixation as a (low cost) alternative for cryonics. In fact, years before all the talk about the “connectome” and “plastination” I spent considerable time exchanging messages with Michael Perry at Alcor about the technical and practical feasibility of chemical brain preservation. But no matter how open minded I tried to be about this approach, I kept running into the same challenges over and over again.

The challenge that has concerned me the most is whether a delayed start of chemical brain fixation will produce incomplete distribution of the chemical fixative in the brain because of ischemia-induced perfusion impairment. Thinking about the technical problem of “no-reflow” is not the first thing on the mind of someone who first hears about the idea of using chemical fixatives to preserve the brain. In my case, this concern was not just “theoretical.” In my lab I have spent many years looking at the effects of cerebral ischemia on cryopreservation and chemical fixation. Last year we decided to broaden our investigations to delayed chemical fixation and we have not been pleased at what we have observed so far. After 1.5 years of room temperature storage the delayed aldehyde fixed brains are falling apart and continue to decompose. In small animals one might imagine that such perfusion impairment could be overcome by immersing the brains in the fixative instead but human brains are simply too large. By the time that the fixative would have reached the core of the brain, extensive autolysis will have occurred.

Another complex problem is to identify a fixation and polymerization protocol that fixes all identity-critical parts of the brain. If aldehydes do not completely fix the lipids in the brain, should we add strong oxidizing heavy metals to stabilize lipids? This is possible in theory but, as a general rule, these chemicals are either very expensive or dangerous to use (or both). Even if we are able to identify a chemical fixation protocol for the brain that can do the job, how can we know that such brains are stable for very long periods of time? Should we follow fixation by embedding with a polymer to inhibit residual biochemical activity? To my knowledge, there is no known embedding protocol that is scalable to human brains due to the extreme viscosity of these plastics.

Recently these issues took a more personal nature for me when I had to think really hard about a reasonable but affordable longterm preservation protocol for a companion animal. I spent many days reading the electron microscopy and fixation literature to come up with a protocol that was better than aldehyde fixation and low temperature storage. Adding calcium to the fixative? What about phenol? Post-fixation perfusion of a viscous cryoprotectant to allow storage at subzero temperatures? That is when I really started appreciating the “magic” of cold temperatures.

Absent a vitrification agent, cryogenic temperatures can cause extensive damage to cells. But one thing we know: whatever the nature of this damage, as soon the brain is below the glass transition temperature of -130°C, all water is either frozen or a vitrified rigid solid. We do not have to worry about any damage getting worse over time, or whether some biomolecules have not been fixed. Cold may be “crude” in its effects but it is exactly because no biochemical process can escape inhibition at very low temperatures that makes it such a powerful personal survival technology.

Originally published as a column (Quod incepimus conficiemus) in Cryonics magazine 2013-1

First symposium on cryonics and dementia

25. July 2012 · Comments Off · Categories: Cryonics, Health, Neuroscience

The recent symposium on cryonics and brain-threatening disorders was a major success. On Saturday, July 7, 2012, around 30 people attended the first ever symposium on dementia and cryonics in Portland, Oregon. The symposium started with a brief introduction by Institute for Evidence Based Cryonics President Aschwin de Wolf, who emphasized why people with cryonics arrangements have a clear interest in understanding and avoiding dementia. The first speaker, Chana de Wolf, introduced the audience to the topic of adult neurogenesis, the two areas in the brain where it occurs, and how little we still understand about it. Aubrey de Grey then talked about the SENS approach to rejuvenation and how some emerging damage repair bio-technologies might be able to also reverse neurodegenerative diseases such as Alzheimer’s disease. Cryonics Institute President Ben Best followed Aubrey’s presentation with a technical introduction about the pathophysiology of Alzheimer’s disease and the treatments that are currently being investigated. Ben is maintaining a page about the molecular mechanisms of Alzheimer’s disease on his personal website.

After the break Alcor staff member Mike Perry presented a detailed analysis of a recent paper in which cerebrospinal fluid samples could predict the onset of Alzheimer’s diseases many years before the first signs of cognitive impairment, a finding that holds great promise for life-extensionists, and those with an increased risk for Alzheimer’s disease in particular. Institute for Evidence Based Cryonics Board member Keegan Macintosh then presented a rigorous legal analysis of the Thomas Donaldson case and indicated how the case could have been argued more persuasively then and now. The last speaker of the day was Alcor President Max More who introduced the concept of the extended mind and its relevance to cryonics and neurodegenerative diseases, which prompted a useful exchange about the desirability of cryonics organizations facilitating members to store identity-critical information. The official meeting ended with a panel discussion moderated by Aschwin de Wolf in which all the speakers took questions from the audience and other speakers.

The program and panel left ample time for interaction between speakers and the audience. The topic of avoiding dementia and what to do when a cryonicist is diagnosed with a brain threatening disorder received a lot of attention. Despite the rather disturbing subject of the symposium there seemed to be a general recognition that it was extremely valuable to explore this topic in the context of cryonics. Some suggestions of how to deal with dementia were made that had not been previously discussed in cryonics publications.

It is not likely that we will organize a symposium about this topic every year but there was a strong interest in organizing meetings about other topics on a regular basis in the Pacific Northwest.

The slides of all but one of the presenters are available on the symposium page and a video recording of Aubrey de Grey’s talk was made by one person in the audience. A more detailed report of the symposium will appear in an upcoming issue of Alcor’s Cryonics magazine.

Chemopreservation in the real world

20. June 2012 · Comments Off · Categories: Cryonics, Death, Neuroscience

It is generally not the task of scientists to consider the legal, financial, and logistical limitations when searching for biomedical breakthroughs but there are good examples where considering the real-world applications of a technology can be instructive. Research aimed at preservation of brains (or the “connectome”) is such an example. Even if chemopreservation can be demonstrated to preserve the intricate wiring of the brain, it can be safely assumed that there will not be a massive change in demand for brain preservation technologies (especially if the technology is too strongly tied to mind uploading). As a consequence, providers of chemopreservation will most likely operate in the same environment as providers of cryonics. That means that, as a general rule, there will be a delay between pronouncement of legal death and the start of procedures.

There is now more than 40 years of mainstream biomedical research demonstrating that even short interruptions of circulation (under normothermic conditions) can produce perfusion impairment in the brain. As has been demonstrated by cryonics researcher Mike Darwin and my own lab, Advanced Neural Biosciences, this “no-reflow” can produce poor distribution of cryoprotectants (including vitrification agents) and associated freezing. One serious concern that cryonics researchers have about chemopreservation-in-the-real-world is that poorly chemically fixed brains will be prone to autolysis during long-term storage. This limitation of chemopreservation applies to both “conventional” biological resuscitation scenarios as to whole brain emulation. One can only recover (or “upload”) what is preserved – or can be inferred. And as far as we understand things today, the advantage of temperature as a long-term preservation method is that it does not depend on a healthy, non-ischemic circulatory system. Cryopreservation of an ischemic brain can produce ice formation, but as soon as it is placed in liquid nitrogen, cold will “fix” whatever there is without further degradation. The same thing cannot be said about chemopreservation under poor conditions.

There is an understandable tendency to compare brain preservation protocols under ideal conditions and favor the method that produces the best preservation. But support for either technology cannot be solely based on results produces under controlled lab conditions. Personal survival technologies should be evaluated under conditions that are most likely to be encountered by organizations that will offer them. Demonstrating that chemical fixation (and plastination) can preserve the connectome is a laudable goal but the case for chemopreservation as a clinical experimental preservation method requires a persuasive response to the objection that delays in fixation can frustrate the aims of chemopreservation in the most fundamental manner.

One interesting aspect of the cryonics vs chemopreservation debate, though, is that it appears that some people simply feel more comfortable with one of the approaches. People who have shown the slightest interest in human cryopreservation can get really excited about the idea of chemical brain preservation. This indicates that if both approaches would be pursued actively, the growth of chemopreservation would not necessarily be at the expense of cryonics but there would be a growth in the total number of people making bio-preservation arrangements aimed at personal survival. But as Mike Darwin has recently pointed out, chemopreservation is not at the stage where it can be responsibly offered. The growth of this field requires a committed group of individuals who will research, develop, and implement this program. Chemopreservation does not need to be perfected before being offered (neither was cryonics) but so far most advocacy has been mostly at the conceptual level.

Alzheimer’s disease and cryonics

01. March 2012 · Comments Off · Categories: Cryonics, Neuroscience

Conventional wisdom in life extension circles is that making cryonics arrangements allows one to benefit from rejuvenation technologies that are not available during one’s existing lifespan. Aside from the risk of high-impact accidents or getting lost at sea, there is one challenge that some cryonicists will face when they grow older; the debilitating consequences of brain-threatening disorders.

One of the unfortunate effects of the increase in human lifespan is a corresponding increase in late-onset identity-destroying brain disorders. We know that some patients at the existing cryonics organizations were cryopreserved after advanced Alzheimer’s disease. Some cryonics organization members who developed Alzheimer’s disease were not preserved at all, due to lapsed insurance and/or cryopreservation arrangements.

The growing awareness that brain-threatening disorders can present a formidable challenge to personal survival is the theme of the latest issue of Alcor’s Cryonics magazine.

To further draw attention to this topic and generate more knowledge how to prevent and treat brain-threatening disorders, the Institute for Evidence Based Cryonics and Cryonics Northwest will organize a symposium on cryonics and brain-threatening disorders on Saturday July 7, 2012, in Portland, Oregon.

Talks include Aubrey de Grey on The SENS approach to repairing the aging brain, Chana de Wolf on neurogenesis in the adult brain and Alzheimer’s disease, Ben Best on drugs, supplements, and other treatments to mitigate and prevent Alzheimer’s disease, Mike Perry on (early) diagnosis of Alzheimer’s disease, and Max More about survival, identity, and the extended mind. Entrance to the symposium is free. More information about the program and registration will be provided soon.

ApoE4 – The Ancestral Allele

05. August 2011 · Comments Off · Categories: Health, Neuroscience · Tags: , , , , , , , ,

Reportedly, when James Watson and Steven Pinker had their genome sequenced, they declined to know their risk for Alzheimer’s disease. Clearly this is not an option for life extensionists and cryonicists, who are better off knowing whether they have a copy or, worse, two copies of the ApoE4 gene.

Patri Friedman, son of the libertarian economist David Friedman (who in turn is the son of the Nobel laureate Milton Friedman), recently learned that he has two copies of the ApoE4 gene when 23andMe updated their reports. Caucasian and Japanese carriers of two E4 alleles have between 10 and 30 times the risk of developing Alzheimer’s by 75 years of age, as compared to those not carrying any E4 alleles. Patri is a life extensionist, practitioner of the paleo diet, and recently made cryonics arrangements with his whole family at Alcor – and is thus far more prone to a pro-active course of action.

When he realized that there was no good central resource for people with copies of the ApoE4 gene he started a new blog called ApoE4 – The Ancestral Allele, which aims to share practical information and research for health-conscious E4 carriers. The first posts discuss some of the benefits of having the E4 gene (better episodic memory) and what kind of diet is recommended for E4 carriers. He also encourages guest posts and other co-bloggers to help run the website.

Medico-Legal Aspects of Human Cryopreservation Optimization

28. May 2011 · Comments Off · Categories: Cryonics, Death, Health, Neuroscience · Tags: , , , , , , , , , , , ,

Introduction

Ongoing legal challenges and hostile interference of relatives have increased awareness among cryonicists that addressing the likelihood that one will be cryopreserved at all should take center stage among other strategies for survival. As a consequence, a number of individuals have recently taken on the task of working out the conceptual and legal challenges to minimize hostile interference (for a contribution on the ethical aspects of cryonics interference, look here).

One aspect of cryonics optimization planning that has received little attention to date is to develop legal strategies to deal with medical and legal issues surrounding one’s death, terminal illness, and the dying phase. In this memo I will outline some of the most important medical and medico-legal issues, how cryonicists could benefit from recognizing them, and suggest some legal and practical solutions. Before I get to the substance of these issues I would like to briefly identify all the stages in which proactive cryonics planning can improve our odds of personal survival.

Opportunities for cryonics optimization

The first and most obvious decision is to make cryonics arrangements. Alcor members face complicated decision making because the organization offers both whole body cryopreservation and neuro cryopreservation. From the perspective of cryonics optimization many members choose neuropreservation because it enables the organization to exclusively focus on what matters most; the brain. There is also a logistical advantage. In case transport of the whole body across state lines is delayed the isolated head can be released in advance as a tissue sample. Additionally, a number of Alcor members have recognized that it is possible to have the best of both worlds and combine neuro-vitrification and separate cryopreservation of the trunk. This allows the member to take advantage of the superior preservation of the brain that is available for neuro patients without having to forego whole body cryopreservation. This option is not widely advertised so one is encouraged to contact Alcor about revisions in funding and paperwork.

The other obvious decision is to have secure funding in place. Many members have given extensive thought about funding mechanism and wealth preservation so there is little need to discuss this here. From the perspective of cryonics optimization it is important to emphasize the importance of over-funding your cryopreservation. This not only protects you against future price increases, but also enables you to take advantage of technical upgrades that cannot be offered at the current preservation minimums. Another aspect to consider is leaving money to cryonics research. Although it is reasonable to expect that general progress in science will include general cell repair, there may be areas that will only be pursued by those who have a scientific or personal interest in resuscitation of cryonics patients. As in many areas in life, diversification is key. One should not solely depend upon Alcor or CI for successful resuscitation research or efforts.

Another important opportunity for cryonics optimization is to recognize the importance of proximity. From a technical point of view, there is simply no comparison to de-animating near the cryonics facility of your choice. This is not just a matter of reducing ischemic time. Remote standby and stabilization is a fertile ground for all kinds of logistical and legal complications. Most cryonics members do recognize the importance of reducing transport times but it is an established fact that as soon people become terminally ill they become more resistant to the idea of relocating and often prefer to die among friends at home. It is important to anticipate this scenario and to not delay relocation plans until the last minute. Another advantage of relocating at an earlier stage is that one is better protected in case of a terminal disease with rapid decline or sudden death.

As mentioned above, one issue that is getting increasing attention is how to protect oneself against hostile relatives and third parties. The take-home message is to alter cryopreservation contracts and your paperwork in such a matter that there is an incentive *not* to interfere.

Last but not least, something should be said about community building. Cryonicists can greatly benefit from becoming active in their local cryonics group. Often these meetings are open to members of all cryonics organizations. Most cryonics groups organize standby and stabilization trainings where members can familiarize themselves with the basics of the initial cryonics procedures. Such groups may not only play a part in your own future cryopreservation but are also useful to get a basic understanding about what you can do in the case a local member or a loved one needs to be cryopreserved. Another important aspect of participation in a local cryonics group is that one remains in contact with other cryonicists. When people get older their friends and family members die and the member has little communication with those who are aware of his desire to be cryopreserved. If you live in an area where there are no local cryonics groups contact your cryonics organization and/or start your own local group.

Physician-assisted dying

If there was more widespread acceptance of cryonics the harmful delay between pronouncement of legal death and the start of cryonics procedures would not exist. After a determination of terminal illness, preparations would be made to ensure a smooth transition between the terminal phase and long term care at cryogenic temperatures.

Some states have enacted legislation that allows a terminally ill patient to request the means to terminate their life.  Assisted suicide is currently legal in the following three states: Oregon, Washington, and Montana. Physician-assisted dying does not remove the current obstacle that cryonics procedures can only be started after legal pronouncement of death but it can bring the timing of death (and thus of standby) under the patient’s control. Utilizing such laws can also greatly reduce the agonal phase of dying and its associated risk of damage to the brain.

The legal requirements for utilizing physician-assisted suicide can vary among states but, as a general rule, require that a patient has been diagnosed with a terminal illness with no more than six months to live, that the patient is of sound mind, and that the request is made in written form and witnessed. The State of Oregon has a residency requirement to discourage physician-assisted dying tourism.

Since cryonics procedures are performed after legal death, there is no reason why cryonics patients are exempt from utilizing these laws. Despite rumors to the contrary, there is no evidence that utilization of these laws require mandatory autopsy. After all, the cause of death in physician-assisted dying is clear; self- administration of the lethal drug. To avoid any possible accusations that cryonics organizations encourage the use of such laws, it is recommended that no person associated with the cryonics organization should be a witness, let alone be the physician that prescribes the lethal drugs.

Sudden death and autopsy

One of the worst things that can happen to a cryonics member is sudden death. Especially when the patient is young with no prior heart conditions, an autopsy is almost guaranteed. There is little one can do to avoid sudden death aside from choosing a lifestyle that reduces cardiovascular pathologies. The only preparation for dealing with sudden death is to become a religious objector to autopsy. Some states (including California, Maryland, New Jersey, New York and Ohio) have executed laws to restrict the power of the state to demand an autopsy. Although exceptions can still be made in cases of homicide or public health there is little to lose in using such provisions. The websites of Alcor and CI have links to the relevant forms to execute. The Venturists are offering a card for their members stating that they object to autopsy. This card can be requested from Michael Perry (mike@alcor.org) at Alcor. An example of such a card is provided below.

Sudden cardiac death is not the only reason for ordering an autopsy. An autopsy is typically ordered if there are criminal suspicions (homicide) or suicide. There is also a greater risk of autopsy when a patient dies in absence of other people. Since many old cryonicists are single and spent a lot of time alone they are also at an increased risk for autopsy. This is another good argument to remain involved with local cryonics groups and in frequent contact with other cryonicists.

If autopsy cannot be avoided it is important that the cryonics organization is notified promptly. Cryonics organizations can make another attempt to persuade the authorities to abstain from an autopsy or to request a non-invasive autopsy that exempts and protects the brain. The cryonics organization can also issue instructions for how the patient should be maintained prior, during and after autopsy. It might be worthwhile to generate a template of general autopsy instructions for cryonics patients. Such a document may not be binding but it could be useful in limiting the amount of ischemia and injury.

The dying phase and Advance Directives

Most cryonics members have a basic understanding of the importance of time and temperature to protect a cryonics patient after legal pronouncement of death. Fewer people recognize the effect of the dying process itself on the outcome of a cryonics case. In best case scenarios (physician-assisted dying, withdrawal of ventilation) the dying phase is relatively rapid while in worst case scenarios extensive ischemic injury to the brain is possible. Little work has been done to outline recommendations for the terminally ill cryonics patient. One of the main objectives of this article is to recognize that cryonics members could benefit from a general template that can be used in their Advance Directives and to guide surrogate decision makers.

At this point it is useful to briefly describe how the dying phase itself can affect the outcome of cryonics procedures (for a more detailed treatment see the appendix at the end of this article). A useful distinction is that between terminal illness and the agonal period. A patient is classified as terminal when medical professionals establish that the patient cannot be treated with contemporary medical technologies. During this period the patient is usually still of sound mind and able to breathe and take fluids on his/her own. Unless the patient has suffered an insult to the brain or a brain tumor, there is no risk for ischemic injury to the brain yet. At some point, however, the body’s defense mechanisms will be overwhelmed by the patient’s disease and the patient enters the agonal phase. The agonal phase, or active dying phase, can be characterized as a form of general exhaustion. The body is still fighting but with decreasing success and efficiency. One of the biggest concerns for cryonics patients is the development of (focal) brain ischemia while the (core) body is still mounting its defense.

It would be impossible to design an Advance Directives template that is optimal for all cryonics patients, but there are a number of general guidelines that can inform such a document:

* All health care decisions should be guided by the objective of preserving the identity of the patient throughout the terminal and dying phase.

* Measures to prolong dying should only be initiated or accepted if they result in less ischemic injury to the brain.

* Life-sustaining measures should be withheld in case of traumatic or ischemic insults to the brain.

To ensure that sensible decisions are made in situations that are not covered by these Advance Directives, a Health Care Proxy can be executed that designates a person to make those decisions. It is understandable to give such power to the person closest to you but in the case of cryonics it is recommended that this responsibility should be given to a person with a strong commitment to your desires and a detailed understanding of the medical needs of cryonics patients.

Pre-medication of cryonics patients

If a critically ill cryonics member is at risk of ischemic brain injury during the dying phase it stands to reason that some palliative treatment options are better than others. One possibility for cryonics patients is to specify such options in one’s Advance Directives. Another scenario in which pre-medication is possible is where the medical surrogate is strongly supportive of such measures. It should be noted that such a decision rests solely with the member or his/her medical representative. Cryonics organizations should not be involved in the pre-mortem treatment of the patient.

There are two important questions about pre-medication of cryonics patients:

1. Is it safe?

2. Is it beneficial?

The answer to the first question has a lot to do with the status of the pharmaceutical agents in question. For example, a supplement like melatonin is less controversial than a prescription drug like heparin. The most important thing to keep in mind is that drugs that may be beneficial after legal pronouncement of death could have adverse effects in critically ill patients. Good examples are drugs that have effects on blood rheology and clotting. One would rather forego the hypothetical benefit of a drug if there is a non-trivial change of triggering major controversies about drugs taken during the dying phase. This leaves only certain supplements as relatively safe options for pre-medication of cryonics patients.

The answer to the second question is not clear. The rationale behind pre-medication is that it can protect the brain during agonal shock and its associated ischemic events. Evidence for this belief is usually found in the peer reviewed literature on neuroprotection in ischemia. However, there is a clear difference between the administration of neuroprotective agents during the dying phase and the administration of neuroprotective agents prior to artificially-induced acute ischemia. One perspective is that such agents are beneficial but only delay the ischemic phase of the dying period. In this case supplements have little neuroprotective effect. An alternative perspective is one where such supplements do not alter the agonal course as such but provide more robust protection after circulatory arrest. Obviously, this matter is not of concern to conventional medicine so there is little evidence to make rational decisions. In light of the previous discussion, the current (tentative) verdict should be that a case can be made for pre-administration of neuroprotective agents but that these agents should be confined to “safe” supplements like melatonin, Vitamin E and curcumin. Whether such a regime would be beneficial needs to be decided on a case by case basis and is, therefore, more in the domain of the Health Care Proxy than Advance Directives.

Do Not Resuscitate Orders

Do Not Resuscitate (DNR) orders present one of the most challenging issues for cryonics optimization. On the one hand, we would like to benefit from any attempt to resuscitate us in case of sudden cardiac arrest (or any other acute events that can lead to death). On the other hand, we would not like to be subject to endless rounds of futile resuscitation attempts that can damage the brain.

One would be inclined to think that resuscitation attempts should be made in case of sudden insults or during surgery but that no resuscitation attempts should be made during terminal illness. In reality things are not that simple. For example, resuscitation may be possible after 8 minutes of cardiac arrest but the patient can suffer severe brain damage as a consequence. Such a scenario can be minimized by executing a DNR at the cost of foregoing any resuscitation attempts at all. Would this outweigh the benefits of successful resuscitation attempts? It is hard to see how an objective answer to this question can be given without taking a specific person’s views on risk and treatment into account. One way to mitigate this dilemma is to make a distinction in your Advance Directives between pre-arrest emergencies (for example, resuscitation should be permitted in the case of labored breathing but presence of heart beat) and full arrest. An in-hospital situation where resuscitation of a critically ill patient would be helpful would be where it would allow a cryonics standby team to deploy at the bedside of the patient. As can be seen from these examples, good resuscitation instructions for cryonics patients require a lot of attention to context. Because confusion could arise whether Advance Directives would include pre-hospital emergency procedures it is recommended to execute an explicit document if you want these cases to be covered – such a document could be complemented by wearing a bracelet.

Creating a general template

This article has identified a number of important medico-legal issues that need to be addressed by cryonicists to optimize their cryopreservation. It has become clear that in the case of many topics we would all benefit from uniform and effective language. The next step is to translate the concerns discussed in this document in clear legal language so that templates can be offered to all members of cryonics organizations to draft their own Living Will and Advance Directives. One potential problem of such a general template is that it may not conform to state regulations and needs additional tweaking to make it valid in the state where the person lives.

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Appendix :  Neurological damage during the dying phase

Securing viability of the brain by contemporary criteria is the most important objective of cryonics standby and stabilization. Recognition of how pathological events in the central nervous system can defeat this objective is of great importance. As a general rule, the risk for increased brain damage is higher during slow dying. For example, when the ventilator is removed from the patient who is not able to breathe on his own the time between this action and circulatory arrest can be short. Conversely, when a patient is going through a prolonged terminal and agonal phase (regional) injury to the brain can occur while the body itself is still fighting for its survival.

The human brain has little storage of excess energy. As a result, hypoxia causes the brain to deplete its oxygen reserves within 30 seconds. The energy depletion that follows cerebral hypoxia during the dying phase has a number of distinct effects: 1) excitation or depression of certain processes in the brain, 2) alteration in the maintenance of structural integrity of tissues and cells, and 3) alteration of neuromediator synthesis and release. The depletion of oxygen leads to a switch from aerobic to anaerobic energy production. As a consequence, there is an increase in the metabolic end-products of glycolysis such as lactic acid which decreases pH in the brain. After 5 minutes no useful energy sources remain in the brain, which can explain why the limit for conventional resuscitation without neurological deficits is put at 5 minutes as well. Because the dying phase leads to progressively worse hypotension and hypoxia the metabolic state of the brain after the agonal phase is worse than if there would have been sudden cardiac arrest.

Light microscopic changes have been observed in brain cells after 5 minutes of ischemia. Prolonged hypotension, as can occur in the agonal patient, can lead to the appearance of “ghost cells” and disappearance of nerve cells. Such observations provide evidence that structural changes, including cell death, can occur prior to clinical death. Another manifestation of hypoxia (or hypotension) is the progressive development of cerebral edema. The resulting narrowing of vessels and decrease of intercellular space can, in turn, aggravate energy delivery to tissues. Of particular importance for cryonics stabilization procedures is the development of no-reflow which can prevent complete restoration of perfusion to parts of the brain during cardiopulmonary support. There is no consensus as to whether no-reflow can occur as a result of prolonged hypotension (as opposed to complete cessation of blood flow), but an extended dying phase can set the stage for cerebral perfusion impairment after circulatory arrest.

The central nervous system does not shut down at once. Throughout the terminal and agonal phase alternations in the brain progress from minor changes in awareness and perception to deep coma. As a general rule, more recent and complex functions of the brain disappear earlier than the most basic functions of the brain. The uneven brain response to hypoxia may reflect different energy requirements, biochemical and structural differences, and/or the activation of protective mechanisms to preserve the “core” functions of the brain. The CA1 region of the hippocampus has been demonstrated to be uniquely vulnerable to ischemia. This presents a problem for contemporary cryonics since the objective of human cryopreservation is to preserve identity-relevant information in the brain.

This article is a slightly revised version of a paper that was submitted for the 4th Asset Preservation Meeting near Gloucester, Massachusetts.

Neural cryobiology and the legal recognition of cryonics

16. May 2011 · Comments Off · Categories: Cryonics, Death, Neuroscience · Tags: , , , , , , , , , , , ,

It has been said that if you want to persuade someone, you need to find common ground. But one of the defining characteristics of cryonics is that proponents and opponents cannot even seem to agree on the criteria that should be employed in discussing cryonics. The cryonics skeptic will argue that the idea of cryonics is dead on arrival because cryonics patients are dead. The response of the cryonics advocate is that death is not a state but a process and there is good reason to believe that a person who is considered dead today may not be considered dead by a future physician. In essence, the cryonics advocate is arguing that his skeptical opponent would agree with him if he would just embrace his conception of death….

Cryonicists have named their favorite conception of death “information-theoretic death.” In a nutshell, a person is said to be dead in the information-theoretic sense of the word if no future technologies are capable of inferring the original state of the brain that encodes the person’s memories and identity. There are a lot of good things to be said about substituting this more rigorous criterion of death for our current definitions of death. However, in this brief paper I will argue that our best response does not necessarily need to depend on skeptics embracing such alternative definitions of death and that we may be able to argue that opponents of cryonics should support legal protection for cryonics patients or risk contradicting conventional definitions of death.

In contemporary medicine, death can be pronounced using two distinct criteria; cardiorespiratory arrest or brain death. A lot of ink has been spilled over the co-existence of those criteria and its bioethical implications but I think that most people would agree that the practice of medicine requires this kind of flexibility. What is interesting for us is that clinical brain death (or brain stem death) is defined as “the stage at which all functions of the brain have permanently and irreversibly ceased.” There are a number of ways how such a diagnosis can be made, but in this context I want to focus on the absence of organized electrical activity in the brain.

We first should note the use of the word “irreversible.” After all, if a patient is cooled down to a low core temperature to permit complicated neurosurgical procedures most of us would not say that this person is “temporarily brain dead.” As a matter of fact, one could argue that cryonics is just an experimental extension of clinical hypothermic circulatory arrest in which there is a temporal separation of stabilization and treatment. Now, we could argue that what may be irreversible by today’s standards may not be irreversible by future standards but then, again, we are trying to persuade the other person to accept our view of future medicine. It would be much better, and I hope much easier, to argue that contemporary cryopreservation techniques can preserve organized electrical activity in the brain. The advantage of this approach is obvious. Instead of arguing in favor of our own criterion of death we can argue that, according to mainstream criteria for determination of death, cryonics patients are not dead. This is an interesting case in which a scientist (i.e., a cryobiologist) may be able to make a major contribution to the legal recognition and protection of cryonics patients.

So where are we standing right now? How good are our preservation techniques? If we aim for reversible whole brain cryopreservation a cryoprotective agent should have two properties: (1) elimination of ice formation, and (2) negligible toxicity. In the early days of cryonics, we were not able to satisfy both criteria at once. Using just a little bit of glycerol would not be toxic but it would still allow massive ice formation. Using a lot of a strong glass former such as DMSO would eliminate ice formation but at the price of severe toxicity. Mostly due to the groundbreaking work of cryobiologists Gregory Fahy and Brian Wowk, in the year 2000 the Alcor Life Extension Foundation introduced a vitrification agent called B2C that eliminated ice formation and had a more favorable toxicity profile. In the year 2005, the separation between the state of the art in experimental cryobiology and cryonics practice was further narrowed when Alcor introduced M22 as their new vitrification agent. M22 is the least toxic vitrification agent in the academic cryobiology literature that permits vitrification of complex mammalian organs at a realistic cooling rate.

M22 and other solutions derived from the same cryobiological principles have been validated in the brain as well. Former Cryonics Institute researcher Yuri Pichugin and collaborators used a related vitrification solution for the preservation of rat hippocampal brain slices without loss of viability after vitrification and rewarming. At a cryonics conference in 2007, 21st Century Medicine announced that the use of M22-based solutions permitted the maintenance of organized electrical activity in rabbit brain slices. So, at this stage we can argue that our existing vitrification solutions have a reasonable chance of maintaining organized electrical activity in brain slices. The next challenge is to demonstrate this property in whole brains.

Whole brain cryopreservation is not just the cryopreservation of a great number of individual brain slices. Brain slices can be cryopreserved by (step-wise) immersion in the vitrification solution. Vitrification of whole brains (even small brains such as rodent brains) requires the introduction of the vitrification solution through the circulatory system. This aspect of whole brain vitrification presents a number of technical challenges. Electron micrographs of vitrified tissue from whole brains, however, indicate that these challenges can be overcome. The current research objective is to perfect perfusion techniques and optimize vitrification solutions to maintain organized electrical activity in whole brains. We know that this objective is possible in principle because the famous surgeon Robert White demonstrated retention of electrical activity in whole isolated brains after cooling them to ~2-3°C. Isolated brain perfusion is a complicated surgical procedure, but the current writer and cryobiologist Brian Wowk have recognized that validation of whole brain activity is also feasible in situ.

Reversible cryopreservation of the whole brain without losing organized electrical activity is not a trivial research objective but it should be easier to achieve than reversible cryopreservation of the whole body and, perhaps, some other organs. If and when we accomplish this, we will no longer be dependent on “rationalist” arguments that appeal to logic and optimism about the future. We can argue that our patients should not be considered dead by the most rigorous criterion for determination of death in current medical practice. We can then even mount some smart legal challenges to seek better protection for cryonics patients. If we can make this step forward we should also aim at improved protection of existing cryonics patients, which will allow them, among other things, to own assets and bank accounts. This is how science can be employed in legal strategies for asset preservation.

This article is a slightly revised version of a paper that accompanied a recent presentation on neural cryobiology and the legal recognition of  cryonics at the 5th Asset Preservation Meeting in Benicia, California.

The case against cryonics

11. March 2011 · Comments Off · Categories: Cryonics, Neuroscience · Tags: , , , , , , , , ,

What is striking about cryonics is that those who have taken serious efforts to understand the arguments in favor of its technical feasibility generally endorse the idea. Those who have not made cryonics arrangements usually give non-technical arguments (anxiety about the future, loss of family and friends, etc), lack funding or life insurance, or are (self-identified) procrastinators. In contrast, those who reject cryonics are almost invariably uninformed. They do not understand what happens to cells when they freeze, they are not aware of vitrification (solidification without ice formation), they think that brain cells “disappear” five minutes after cardiac arrest, they demand proof of suspended animation as a condition for endorsing cryonics, etc.

This does not mean that no serious arguments could be presented. I can see two major technical arguments that could be made against cryonics:

1. Memory and identity are encoded in such a fragile and delicate manner that cerebral ischemia, ice formation or cryoprotectant toxicity irreversibly destroy it. Considering our limited understanding of the nature of consciousness, and the biochemical and molecular basis of memory, this cannot be ruled out. Cryonics advocates can respond to such a challenge by producing an argument that pairs our current understanding of the neuroanatomical basis of identity and memory to a cryobiological argument in order to argue that existing cryonics procedures are expected to preserve it. An excellent, knowledgeable, response of this kind is offered in Mike Darwin’s Does Personal Identity Survive Cryopreservation? Cryonics skeptics in turn could produce evidence that existing cryonics procedures fall short of this goal.

2. The cell repair technologies that are required for cryonics are not technically feasible. This argument should be presented with care and rigor because the general argument that cell repair technologies as such are not possible contradicts existing biology. A distinct difference from the first argument is that it is harder, if not impossible, to use existing empirical evidence to settle this issue. After all, making cryonics arrangements is a form of decision making under uncertainty and such decisions are not straightforwardly “correct” or “incorrect,” “right” or “wrong.” What can be done is to provide a detailed scientific exposition of the nature and scope of the the kind of repairs that are necessary for meaningful resuscitation and to argue that both biological and mechanical cell repair technologies are not conceivable – or are conceivable.

One thing that becomes immediately clear from this exercise is that there is no single answer to the question of whether cryonics can work because the answer to this question depends on the conditions and technologies that prevail during the cryopreservation of a patient. This introduces a set of more subtle distinctions concerning the question of what kind of cryonics should be assessed. It also produces an argument in favor of continuous improvement of cryonics technologies, and standby and stabilization services.

This short examination of technical arguments that could be made against cryonics gives advocates of the practice two talking points in discussion with skeptics or hostile critics:

(a) If a critic flat-out denies that cryonics is technically feasible, it is not unreasonable to ask him/her to be specific about what (s)he means by cryonics. This simple question often will reveal a poor understanding of existing cryonics technologies and procedures.

(b) A decision made on the basis of incomplete knowledge cannot be “right” or “wrong” and should be respected as one’s best efforts to deal with uncertainty.

The RhinoChill: A New Way to Cool the Brain Quickly

20. January 2011 · Comments Off · Categories: Neuroscience, Science · Tags: , , , , , ,

We scientists are difficult, cranky, and above all, maddeningly frustrating people. Want to turn lead into gold? No problem, we can tell you how to do that, and in fact have even done it already: the only catch is that the cost of such ‘nuclear transmutation’ is many times that of even the most expensive mined gold. You say you want to travel to the moon? Done! That will be ~$80 billion (in 2005 US dollars). Want to increase average life expectancy from ~45 to ~80 years? Your wish is our command, but be mindful, you will, on average, spend the last few of those years as a fleshpot in the sunroom garden of an extended care facility.

And so it has been with an effective treatment for cerebral ischemia-reperfusion injury following cardiac arrest. Thirty years ago, laboratory scientists found a way to ameliorate most (and in many cases all) of the damage that would result from ~15 minutes of cardiac arrest, and what’s more, it was simple! All that is required is that the brain be cooled just 3oC within 15 minutes of the restoration of circulation. The catch? Well, this is surprisingly difficult thing to do because the brain is connected to the body and requires its support in order to survive. And the body, as it turns out, represents an enormous heat sink from which it is very difficult to remove the necessary amount of heat in such short time. Thus, the solution exists and has been proven in the laboratory, but it has been impossible to implement clinically.  This may be about to change as a variety of different cooling technologies, such as cold intravenous saline and external cooling of the head begin to be applied in concert with each other. Separately, they cannot achieve the required 3oC of cooling, but when added together they may allow for such cooling in a way that is both effective and practical to apply in the field.  A newly developed modality that cools the brain via the nasal cavity may provide the technological edge required to achieve the -3oC philosopher’s stone of cerebroprotection.

Read the complete article in PDF here.

Prospects for Mild Therapeutic Hypothermia and Improved CPR in Cardiopulmonary Cerebral Resuscitation

15. January 2011 · Comments Off · Categories: Neuroscience, Science

There are two kinds of hypothermia: protective or preservative hypothermia, and therapeutic hypothermia. The former is easy and straightforward to understand for most, clinicians and laymen, alike.  However, therapeutic hypothermia has proved to be a far more difficult idea to communicate, probably because it is so easy to conflate it with protective hypothermia.

Anyone who has had any contact with refrigeration will at once understand the concept of protective hypothermia. Foodstuffs, and other biological materials that are cooled, experience protection against spoilage and decay roughly in proportion to the degree to which they are cooled. A little cooling slows decomposition a bit, and enough cooling will stop it altogether. Again, the temperature-induced decrease in the rate of chemical reaction is a fundamental property of chemistry which is understood intuitively by anyone who lives where it gets cold, or where refrigeration is in use.

By contrast, therapeutic hypothermia does not rely primarily upon the slowing of metabolism or the rate of chemical reactions that occurs as a result of cooling, but rather upon the effects very modest degrees of cooling have on gene activation and signal transduction in mammals. Controlled, mild therapeutic hypothermia (MTH) is generally understood to constitute a reduction in body temperature from ‘normal’ for the species being treated, to 3oC below normal. In the case of humans, this would mean a reduction in body temperature from 37oC to 34oC. Such a modest reduction in temperature results in profound down-regulation of pro-inflammatory cell-signaling pathways and causes the inactivation of genes involved in a multiplicity of deleterious cellular and systemic processes. Similarly, MTH can inhibit apoptosis of brain cells, and slow or halt the downward spiral of excessive metabolic demand by injured cells, causing yet more non-productive hyper-metabolism, and consequently even more cell death. In this article, the biomechanics of MTH are briefly explored, as well as the prospects for improved outcomes in patients who suffer anoxic-ischemic brain injury as a result of cardiac arrest as a result of the rapid application of MTH following the insult.

Read the complete paper in PDF here.

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