THE SCIENTIFIC CONQUEST OF DEATH:
- LIFE AFTER DEATH?
- VITRIFICATION / DEVITRIFICATION
- FUTURE PROSPECTS AND ODDS
- RESOURCES & REFERENCES
By the middle of this century, possibly much sooner, human kind will have more than likely defeated the aging process through science and technology. But what if, for whatever reason, you don't survive long enough to take advantage of these advances? There is one possibility available that may allow anyone to actually cheat death and wait for as long as it takes until technology can keep you alive. This possibility is known as cryopreservation.
Cryonics - preservation and storage at ultra-low (cryogenic) temperatures - offers the unprecedented possibility of allowing the older generations of people alive today, and those with terminal illnesses, to take advantage of the (nano)technology of tomorrow in order to prolong life. Cryonics, also called cryonic suspension, ultrahibernation, or cryostasis, is the technique used to store human bodies at extremely low temperatures with the hope of one day reviving them and restoring them to health. Mature molecular nanotechnology, is expected to infer the ability to heal cells at a molecular level and is a vital component of this theoretic life support technology. Cryonics should not be confused with cryogenics, which is defined as, "The branches of physics and engineering that involve the study of very low temperatures, how to produce them, and how materials behave at those temperatures."
LIFE AFTER DEATH?Functional (or behavioral) neuroanatomy and neurobiology have shown us that the immaterial concepts of memory and personality are in fact embodied in matter. When you think, feel, act or remember, the molecular machinery of the brain does something. It stands to reason, then, that by preserving the structure of cells and the patterns of their proteins, it should be possible to preserve the "structure" of the mind and self. If consciousness arises from this structure, it should also be possible to preserve and restore it.
"We know that secondary memory does not depend on continued activity of the nervous system, because the brain can be totally inactivated by cooling, by general anesthesia, by hypoxia, by ischemia, or by any method, and yet secondary memories that have been previously stored are still retained when the brain becomes active once again. Therefore, secondary memory must result from some actual alterations of the synapses, either physical or chemical." — Page 658, Textbook of Medical Physiology by Arthur C. Guyton, 1986
Scientific naturalism tells us death is the end; the total, absolute, permanent, irredeemable end of everything that you are. This may or may not be true, and science may not be able to give us a definitive answer as to the nature of death. If it is simply the end, cryonics is currently your best bet for living longer in the physical plane. If there is a continuation of consciousness into the afterlife, it is hard to imagine that cryonics would interfere with this in any significant way, other than to delay its onset, similarly to other life-extending medical treatments. For anyone who enjoys life and/or is unsure about death, cryonics offers an attractive alternative to just "hoping for the best."
"Human embryos are routinely preserved for years at temperatures that completely stop the chemistry of life. Adult humans have survived cooling to temperatures that stop the heart, brain, and all other organs from functioning for up to an hour. These and many other lessons of biology teach us that life is a particular structure of matter. Life can be stopped and restarted if cell structure and chemistry are preserved sufficiently well." - Alcor
VITRIFICATION / DEVITRIFICATION
A common misconception is that ice formation causes most of the damage to cells that are "frozen" and subsequently thawed out. The truth is that frozen cells are damaged through compression from ice expanding around cells and extreme dehydration caused when the ice forming in extracellular spaces pulls water molecules through the cell membrane by a process known as osmosis. By using a high enough concentration of a cryoprotectant to displace the water in a body, it is possible to "freeze" tissue without causing ice crystals to form at all. This process, which turns water into a glass rather than crystalline ice, is called vitrification.
"It is now possible to physically vitrify organs as large as the human brain, achieving excellent structural preservation without freezing." - Alcor
Cryopreservation is performed as soon as possible after "legal death" has been declared. Legal death simply means that current medical technology is incapable of restoring life to a person. Cryonics places people in biostasis until a time that medical technology can reverse all damage induced by the vitrification process, and cure the medical condition that originally caused legal death.
"It is quite clear that clinically defined death, which in most states is simply the cessation of cardiac and respiratory activity, does not mean that all of the cells of the body have died. It simply means that the cells required to maintain/sustain life, namely, cardiac muscle cells and diaphragmatic muscle cells no longer function adequately."
— The National Human Neural Stem Cell Resource
Paradoxically, ice crystal formation (devitrification) is much more of a problem on rewarming of vitrified tissue than it is on cooling it. This fact is known as "The Devitrification Problem." One potential solution to this problem is uniform rewarming at a very fast rate. It is necessary to rewarm at a rate of 1667°C/second in order to completely prevent devitrification. This is potentially achievable, without significantly damaging tissues, through radio frequency rewarming. Another method of preventing devitrification is to use anti-nucleators, such as polyvinyl alcohol. These are capable of preventing ice crystals from "seeding" upon rewarming. Finally, a third potential option would be to use such a high concentration of cryoprotectant that ice cannot form. Unfortunately, all cryoprotectant agents are toxic to some degree. This results in a trade-off between toxicity and devitrification. It is hoped that through nanotechnology or even advanced pharmacology alone, it will be possible to negate these issues in the future. Current 21st Century cryoprotectant/ice blocker formulations are already able to prevent devitrification entirely in small samples (10ml) with rewarming rates as low as 0.4°C/minute.
The reversibility of cryopreservation will depend upon Molecular Nanotechnology (MNT.) Cryonics is not currently reversible, and so is considered a speculative life support technology. "The eventual perfection of cryonics will be of great value to fields such as medicine and space travel."
The brain is considered the most essential organ in the human body, in fact it is the only organ deemed vital to the preservation of a cryopreserved patient. From a certain perspective, the body can be seen solely as a life support system and protection for the brain. Vitrification of the brain (head) only, known as "neuropreservation," is a less expensive and easier method of preserving a cryonics patient.
"Future physicians may decide that the best way to reverse this damage will be to regrow a young, healthy body around the repaired brain of a cryonics patient rather than devise separate repair strategies for all the different organs and tissues of the body. In both nature and industry, replacement of damaged parts is usually easier than repair. If so, then the extra money spent for whole body preservation today may be wasted." - Alcor
Despite the amazing progress that has been made in transplant medicine over the past generation, the field remains severely limited by its inability to store organs for any significant amount of time. 36 hours is currently the upper limit of time available for organ allocation, transportation, and transplantation. Whole organ vitrification offers a unique potential solution to this problem, which would allow virtually indefinite storage and stockpiling of organs for transplant.
FUTURE PROSPECTS AND ODDS
"So far, embryos, ova, ovaries, skin, pancreatic islets and blood vessels have been vitrified and then devitrified for transplant. Successful devitrification of whole organs like kidneys, livers, hearts and lungs isn’t too far off."
RESOURCES AND REFERENCES
Medical Time Travel