Recently, a 14-year-old girl with terminal cancer has successfully cryogenized. Each time, the number of people asking to be frozen after dying increases, hoping that the scientific advances will allow one day to wake up again and "cure" the conditions that caused them to pass. But what possibilities are there for this to arise one day?
Nature has shown us that it is possible to cryopreserve animals such as reptiles, amphibians, worms and insects. Nematode worms trained to recognize certain odors retain this ability after being frozen; The wood frog is frozen during the winter in a block of ice, for example. However, in human tissue, the freeze-thaw process causes significant damage. Understanding and minimizing this damage is one of the objectives of cryobiology.
At the cellular level, these damages are still little known, but they can be controlled. Every step forward in this field is based on two aspects: improving preservation during freezing and recovery after thawing. During freezing, damage can be avoided by modulating the temperature and relying on various types of cryoprotectants. One of the main goals is the inhibition of the formation of ice that can destroy cells and tissues. For that reason, one of the objectives is not to "freeze" people, if not what is called a "glass phase", a very quick cooling.
For this, simple substances such as sugars and starches have been used to change the viscosity and protect the cell membranes. Chemicals such as dimethylsulfoxide, ethylene glycol, glycerol and propanediol are often used to prevent intracellular ice formation, and also antifreeze to inhibit ice growth and re-crystallization during thawing.
But we do not just have to worry about individual cells; In a freezing state, the tissues are, in general, biologically stable. Biochemical reactions, including degeneration, are delayed at ultra low temperatures to a point where they stop. However, there is a risk that frozen structures may experience a physical disruption, such as cracks. Then, after thawing, the thermal fluctuation involves a number of problems. Cells and tissues can be damaged in this state. But this also has an effect on our "epigenetics" (how lifestyle factors and the environment influence our genes), causing it to reschedule. However, antioxidants and other substances can help you recover after thawing and prevent damage.
Cryopreservation may be an interesting method, but perhaps in other ways: it has been successfully performed on "simple" body parts, such as the fingers and legs. Some complete organs (kidney, liver, intestines) have been cryopreserved, thawed and transplanted into animals. While human organ transplantation is currently based on refrigerated organs, there is a strong scientific current that supports research for the development of cryopreservation of whole organs for therapeutic purposes.
The biggest obstacles
Cryopreservation of the whole brain is the greatest interest. Experiments with frozen animal brains have not been carried out since the 1970s. While factors such as good blood supply and high tolerance to mechanical deformation may facilitate brain freezing, there are certain technical and scientific problems , Especially when the goal is to preserve regulatory function and memory. Without major advances in this type of research, it is likely to remain one of the factors that slow the therapeutic application of cryopreservation throughout the body.
But there is another great obstacle to cryonics: not only to repair the damage caused by the freezing process, but also to reverse the damage that led to death; And all in a way that the individual wakes up being aware of who he is.
So will it ever be possible to cryopreserve a human brain in such a way that it can be restored in an intact way? As explained, success will depend on the quality of the cryopreservation as well as the quality of the reactivation technology. The first one is still poor, so it will wait.
Reference:
IFLScience
