In the 1960s, Robert Ettinger first created the concept of cryonics in his book, The Prospect of Immortality. Now, you may be wondering: what exactly is cryonics?
Cryonics is the preservation of humans or animals at very low temperatures after legally announced death. Its goal is to eventually be able to revive the preserved beings and cure any possible disease they may have. However, currently, only preservation is possible, not revival.
So… how does it work then?
The science behind cryonics originates from the concepts of cryopreservation and cryobiology. In nature, this can be seen in animals like the northern wood frog, which survives freezing conditions by allowing 60 to 70 percent of its body water to freeze for multiple months, also known as cryoprotection. The lowered temperatures of the tree frog slow or stop metabolism, protecting it from ischemic injury – tissue damage caused by lowered or no blood flow.
However, this freezing is not possible without cryoprotectants(CPAS), such as glycerol and dimethyl sulfoxide(DMSO), which prevent ice crystal formation. The northern wood frog uses glycerol and glucose as the cryoprotectant in their blood, stored in the liver glycogen, and turned into glycerol and glucose once the freezing process initiates.
An important thing to note is that the cryoprotectants do not ensure no difficulties, as there are various methods to cryopreservation – programmable slow freezing, vitrification, and low-CPA vitrification – all of which end with the same general end result, yet the method of vitrification reduces or prevents the possibility of damaged ice crystals being formed. Vitrification turns the tissue into an almost “glass-like” state and allows cells or tissues to be frozen without freezing damage.
This leads us to today’s cryopreservation success. Cells, sperm, and embryos are all relatively common examples of successful freezing and revival that are used in modern medicine. In addition, tissues and organs can sometimes be preserved in a shorter-term time span, but still preserved nonetheless. One example is brain tissue, known to be highly complex and fragile, which can only be partially preserved, as only some neural markers remain intact.
These issues with freezing tissue and organs, which are what make up the human body, cause freezing a whole human to be problematic.
There are also many other problems beginning with cryodamage, where ice crystals damage cells and possibly structural stress, leading to cracks or ruptures. Next, there are brain preservation issues, which were partially mentioned before. As the brain is what runs the body, it is the most important organ to preserve, however anoxia (oxygen loss) and reperfusion injury (damage caused by the return of blood) are two main problems. It is also unknown if memories would survive the freezing and revival. The chemicals used in cryonics could also cause damage to the cells due to the high concentrations needed, along with the matter of the different cell types, which cause different issues. Cryonics uses one method of preservation for the entire body, which could prove to be a problem in the future when revival attempts are made.
Apart from scientific issues, there are also more typical matters, such as cost, which can range from $28,000 to $200,000 and would require lifelong planning; legal and ethical issues, since cryonics is not a legally recognized medicine; and simply the limited research revolving around the topic.
Despite the possible problems, there are claims of 300+ patients in a facility in the United States under the Alcor Life Extension Foundation, with over 1,200 people signed up for the procedure post-death as of 2014.
You may now be asking, “What exactly is this procedure?”
It begins after death, it is required that there be formal consent given prior. Time is extremely important in this procedure, as the process starts 1-2 minutes post-death. First, there is rapid cooling in an ice bath, then artificial circulation through CPR-like support. The required amounts of cryoprotectants are then injected, and cooling continues to occur. After this, the body will be stored in liquid nitrogen at a temperature of -196 degrees Celsius. It is important to note that this is only the preservation process, and the revival process has not been tested yet, as there is currently no technology that exists that would allow for this to occur. The cellular damage would have to be repaired, along with reversing the initial cause of death, and restoring any issues with brain function and memory.
While it is possible that cryonics may work, there is no current concrete proof. However, there is progress being made when it comes to research about hypothermia, which is used to protect the brain and can extend survival after cardiac arrest. There are also advances in organ preservation, such as the heart, lungs, and skin, which are important for transplants. It is important to note, though, that there is currently no explicit research on cryonics and the revival, as there are legal issues, along with pessimistic views on the actual feasibility of cryonics.
Authored by Diya Vipin Pillai and Katherine Yao