There may be an insurmountable difficulty in relation to the revival of the cryopreserved cadaver
Cryopreservation consists of preserving human individuals or organs at very low temperatures (less than -130°) in order to preserve them. The low temperatures decrease the metabolism and facilitate preservation.
Cryopreservation begins by bringing the person to a state of hypothermia as quickly as possible in order to reduce cell damage. Anticoagulants (heparin) and vasodilators (nimodipine) must also be administered.
When a cardiorespiratory arrest has occurred, the patient must be placed in support or container that is suitable for inducing hypothermia (iced water or other alternative systems). Cardiopulmonary support maneuvers are performed, treatments are administered and intravenous lines are inserted that allow the blood to be exchanged for cryoprotectant solutions.
At least one artery and one vein must then be cannulated in order to enable the exchange of blood for a cryoprotectant solution (usually ethylene glycol, dimethyl sulfoxide or other components) that prevents the formation of ice crystals, allowing vitrification of the cells while preventing damage due to the crystals. Exchanging the blood for a cryoprotectant solution takes place at hypothermia temperatures — preferably less than 10°C — since at these temperatures the solution can transport as much oxygen as blood. Once the blood has been exchanged for the cryoprotectant, rapid cooling below 0°C should be performed. This cooling can be carried out with dry ice, which allows the temperature to be lowered to -79°C, or with liquid nitrogen, which enables a temperature of -196°C to be reached. Nevertheless, once a temperature of -130°C has been reached, the arrest of the cell’s biological time is complete and the procedure can continue slowly until it reaches the -196°C of liquid nitrogen.
Finally, the individual is placed inside a cryostat consisting of two walls separated by an inner vacuum, where they can be maintained at -196°C – indefinitely in principle – until a way of reversing the vitrification process is found (description taken from a report by Dr. Luis Estrada).
There are currently around 250 cryogenically frozen individuals in the United States and more than 100 on the waiting list to be cryopreserved when the time arrives. In Clinton Township, in the state of Michigan (USA) is the Cryonics Institute, which is dedicated to human cryogenic freezing. Eighty-three frozen humans are currently stored in the Institute, as well as various pets, including 20 cats, 15 dogs, three parrots and a hamster.
The director of the Institute, Robert Ettinger, already 89 years old, had his mother cryogenically frozen in 1982, his first wife in 1987 and his second in 2000. One of the ethical concerns raised by cryogenics is that if these bodies could actually be resuscitated after a long period of time, the individual could find themselves in a human environment that is completely unknown to them, i.e. they would not know anyone. This is not the case of Ettinger of course, who could find himself with his mother and two wives — although the latter could be more of a hindrance than a help!
Ethical and moral assessment
We are going to divide our comments into two parts: technical and ethics or morals.
In our opinion, the main problem that arises in the cryogenic freezing of human beings is that there is no previous experimental evidence that can somehow guarantee the success of this practice. As we very well know, commencing biomedical experiments in humans first requires exhaustive preclinical experiments in animals, which at least guarantee that the technique to be implemented will not have adverse consequences for the human individuals in whom it is to be used.
In this respect — to take one example — we recall that when North American biopharmaceutical company Geron sent a proposal to the United States Food and Drug Administration (FDA) requesting approval to use embryonic stem cells in the treatment of spinal cord injuries, the proposal was rejected because — in the opinion of the FDA — there were no preclinical experiments of sufficient weight to guarantee an absence of side effects in the patients in whom it was to be used; the trial could not therefore be recommended. This was despite the fact that Geron had presented a report of more than 20,000 pages listing previous experiments in animals, although the use of embryonic stem cells for this clinical end was later approved. Nonetheless, this case shows how sufficient previous experiments in animals are required to approve use in humans.
It may also be of interest to highlight that, in 2012, the Nobel prize in Physiology or Medicine was awarded to professor Shinya Yamanaka, who in 2007 developed a technique for reprogramming adult somatic cells. This Nobel prize was surely awarded to him owing to the immense possibilities opened up by this technique, in both the experimental and biomedical fields. Nevertheless, the first clinical trial with reprogrammed (iPS) cells did not start until 2015, which shows the prudence with which these new technologies are evaluated. In this case, the technique was used to treat a patient with age-related macular degeneration, in a trial that is currently underway in the Riken Institute in Japan. In July 2015, however, the Institute reported that it had halted the trial because it seemed that in the second patient, small genomic alterations had been detected following the cell reprogramming procedure. So, what does all this mean? It means that, in order to be able to apply a new experimental technique such as cryopreservation, there must be reasonable certainty that there are no negative side effects in the individuals in which it is to be used.
To support the use of this technique, it has occasionally been argued that previous experiments have been conducted with some invertebrates, and it seems also with some small mammals, in which the cryogenically frozen animal’s body was restored. I have not stopped to delve deeper into these claims, but I believe that to think that this research opens the possibility for use in humans is unfounded. Successful restoration of higher mammals following cryogenic freezing — particularly non-human primates — would have to be demonstrated, which is not an easy matter owing to the long time it would take. I think that, until this is proven, it is a non-experimental evidence-based risk to use these techniques in humans, especially if we consider that up until now, scientists have been unable to vitrify whole organs, although experiments are underway in this field, particularly to recover their functionality once thawed. There is a further biological issue that I think needs to be taken into account. Although some authors occasionally report the ability to recover vitrified oocytes, and that the success of this practice could be extrapolated to whole human bodies, I do not believe there is any scientific basis for this comparison. The oocyte is a single cell, while the human body has billions of cells — more than 200 different types. When a vitrified oocyte is thawed, the process takes place at the biological rhythm of a single cell. How can we be sure that in the cryogenic freezing of a whole body, the biological rhythms of each of the cell lines will be similar? In particular, how can we be sure that in the event of “resuscitation” of that body, the different biological rhythms of cell recovery would be able to take place harmoniously, so that recovery of the entire body is feasible?
In addition to the above difficulties, complex organisms are known to be unable to survive vitrification, because in theory, the formation of crystals that which occurs at the very start of the process must be prevented in order do so. This would require a suitable cryoprotectant that was non-toxic, could enter the cells rapidly, and could be easily removed at the end of the process, something which is not currently available.
These are reasonable questions that I believe need to be clarified before implementing cryogenic freezing of human individuals.
There are undoubtedly minor technical problems that could be assessed, but I think these are secondary to those I have mentioned above.
Most certainly the two scenarios in which this practice can be carried out are: either the individual is in the process of dying but is still alive, or he is already dead, i.e. they are acting on a cadaver. Let’s analyse both circumstances separately.
In the first case, if the subject is still alive — and since as far as I know there is no explicit Catholic Church Magisterial teaching on this practice — I think that the criteria used to morally assess human embryo freezing could be applied, because from a moral point of view, there is no difference in how an early human embryo and an individual adult should be treated. What though does the Magisterium of the Church say about human embryo freezing? We shall refer to two texts on this matter: the first from the Instruction Dignitas Personae from 2008, and the other from Pope John Paul II. The first states that: “Cryopreservation is incompatible with the respect owed to human embryos: it presupposes their production in vitro; it exposes them to the risk of death or physical harm, since a high percentage does not survive the process of freezing and thawing; it deprives them at least temporarily of maternal reception and gestation; it places them in a situation in which they are susceptible to further offense and manipulation”.
In the second, John Paul II made an “appeal to the conscience of the world’s scientific authorities and in particular to doctors, that the production of human embryos be halted, taking into account that there seems to be no morally licit solution regarding the human destiny of the thousands and thousands of ‘frozen’ embryos which are and remain the subjects of essential rights and should therefore be protected by law as human persons”.
That is, it seems morally illicit to freeze human embryos, which can certainly be extrapolated —and with much greater reason — to a human adult.
The second scenario is that it involves a cadaver, and in this case it should be treated as such. There is Catholic Church Magisterial teaching on this matter, which in our opinion is applicable by analogy to what should be done with cryogenically frozen cadavers.
In this regard, there does not appear to be any problem for cryogenic freezing if the cadaver is treated with the respect merited by human remains.
From a moral point of view though, there may be an insurmountable difficulty in relation to the revival of the cryopreserved cadaver, in the hypothetical case that it could return to biological life. In this circumstance, we would have to ask: would that cadaver recover its individual soul? Or would another have to be created for it? These are theological issues that are difficult to resolve. I think that the revival of resuscitated bodies at the end of times, set out clearly in Gospel texts, has nothing to do with the “resuscitation” of these bodies in a period close to their natural death. I believe that this “temporary” revival is not easily compatible with the eschatological resurrection of the body.
- From a medical point of view, there appear to be unquestionable difficulties for human cryogenic freezing, since there are no previous studies that guarantee the absence of negative side effects, and especially the objective possibility of returning the cryogenically frozen individual to life.
- From a moral point of view, in the case of individuals cryogenically frozen before death, i.e. in the process of dying, we consider that subjecting them to a cryogenically frozen state is an act incompatible with the human dignity of those individuals.
- In the case of cadavers cryogenically frozen after dying, i.e. after separation of the body and soul, we think that there may be a serious problem, theologically unresolved, as regards the revival of that body, in the event that its restoration was achieved.
Justo Aznar. Bioethics Observatory
Catholic University of Valencia