Suspended Animation Research
A related research project under development at CCR is a liquid ventilation system for ultra-rapid cooling. For most medical uses, only moderate-to-rapid cooling for a relatively short period is needed. To develop the first phase of suspended animation, however, more rapid cooling is necessary because the objective is to continue cooling the patient until long-term care can be provided at ultra-low temperatures. CCR has demonstrated that a larger heat exchanger can facilitate an adequate cooling rate for this purpose.
Life Extension is also funding the design and construction of a computerized perfusion system at a laboratory in Florida for use in suspended animation research, as well as a new advanced cryogenic system at a laboratory in New York to provide safe, stable, long-term care for cryopreserved humans.
Long-Term Suspended Animation
The key to long-term suspended animation is cooling patients to a temperature low enough to stop all biological processes indefinitely without damaging the patient. The technology needed to accomplish this is known as vitrification. Life Extension funds vitrification research at another laboratory in California called 21st Century Medicine, or 21CM (www.21CM.com).
Scientists at 21CM are making rapid progress in developing vitrification methods to cryopreserve cells, tissues, organs, and entire organisms. In the process of striving for its ultimate goal—achieving long-term suspended animation in humans—21CM is making major advances to help the development of medical fields such as transplantation, regeneration, and rejuvenation. 21CM’s vitrification technology will be needed to create banks of cryopreserved tissues and body parts for use in therapies to cure killer diseases and make people younger in the future.
To achieve these goals, Life Extension is funding several vitrification research projects at the 21CM lab.
|Figure 8. The kidney on the right was vitrified, while the kidney on the left was frozen. There is massive ice formation inside and outside of the frozen kidney, while there is virtually no ice in or on the vitrified kidney, which looks like a natural kidney at normal body temperature. Both kidneys were photographed at -140° C.|
Transplanting Cryopreserved Kidneys
Dr. Gregory Fahy, 21CM’s chief scientific officer, is the world’s foremost expert in the vitrification of biological systems. Dr. Fahy has been working for decades to cryo-preserve kidneys well enough to transplant them successfully, first at the American Red Cross in Maryland and now at 21CM in California. The 21CM lab is the only one in the world currently pursuing vitrification of large tissue masses. Another key scientist working at this lab is Dr. Brian Wowk, who has developed the world’s first practical ice-blocking compounds, which are used with combinations of cryoprotective chemicals in 21CM’s vitrification solutions. These solutions allow tissues to be cooled to extremely low temperatures without the formation of ice. At about -123° C, these tissues are transformed into a glass-like state, which differs dramatically from the crystalline state that occurs during freezing. Vitrification stops life processes cold, without the structural and biochemical damage caused by ice crystals. (Fig. 8.)
Survival of the First Vitrified Kidney
At the annual meeting of the Society for Cryobiology in July 2005, Dr. Fahy announced the survival of a rabbit that received a transplanted kidney after the organ had been vitrified to -130° C and then re-warmed. This result was based on the vitrified kidney’s ability to provide sole renal life support in the recipient animal until it was removed for examination 48 days after it was transplanted. The transplanted kidney sustained some damage from ice formation in its center, but that damage was entirely absent in other parts of the core of the kidney, enabling the organ to support life in a normal fashion.
This remarkable achievement is a major medical milestone that moves us closer to establishing banks for the long-term cryopreservation of human organs. This research is currently being written up for publication in a scientific journal, while further research to perfect the vitrification of rabbit kidneys continues. In 2004, Dr. Fahy and colleagues published a paper reporting the survival of eight rabbits that had received re-warmed transplanted kidneys that had been cooled to -45° C. This breakthrough was based on earlier advances involving the ability to control cryoprotectant toxicity, nucleation, ice crystal growth, and chilling injury.10
21CM has also had success in developing new methods for short-term storage of kidneys and hearts, as well as vitrification of cartilage and corneas. It has been particularly successful in vitrifying corneas, which cannot be frozen effectively. Corneas are complex structures in the eye that often become opaque with advancing age, which can result in blindness. Corneas vitrified by 21CM scientists generally show no cell loss or cell death, and remain transparent after transplantation.
Vitrifying Brains and Whole Organisms
The most ambitious research being performed at the 21CM laboratory involves experiments to vitrify rabbit brain slices, entire rabbit brains, and entire rabbits. The short-term potential of this research includes the use of well-preserved brain slices to test potentially therapeutic drugs and antidotes to potential biological and chemical weapons of mass destruction. This research could also lead to the availability of well-preserved brain sections for neurobiology experiments and the treatment of brain diseases such as Parkinson’s and Alzheimer’s. This research is also essential for achieving suspended animation in humans, which could be instrumental in radically extending the life span of millions of people.
|Figure 9. Joon Chang (left) and Dr. Yuansheng Tan evaluating brain-slice |
electrical activity at 21CM’s state-of-the-art recording station. Dr. Tan is observing a hippocampal brain slice through a microscope located in a Faraday cage that screens out environmental electrical signals while he inserts electrodes into the slice. Mr. Chang is monitoring the results of Dr. Tan’s activities on a virtual oscilloscope.
Recovering Viability in Brain Slices
One test we have used to evaluate brain slice function after vitrification and re-warming is the potassium/ sodium ratio, or ion transport capacity. Another is to determine whether there is normal preservation of slice structure. These tests have shown apparently normal structure and function in hippocampal brain slices. The hippocampus is an area of the brain involved in memory consolidation, storage, and retrieval, and is the part of the brain most sensitive to oxygen deprivation. To further evaluate the effectiveness of its brain studies, 21CM has established an in-house neurophysiology laboratory to measure electrical activity in brain slices and sections. This lab is headed by Dr. Yuansheng Tan, who is assisted by Joon Chang. (Fig. 9.)
In initial studies, it was determined that vitrified, re-warmed brain slices were alive but electrically silent. After several refinements in technique, the 21CM brain slice team was able to achieve essentially normal electrical responses in up to seven of nine slices, which compares favorably to the rate of normal electrical responses in uncooled control slices not exposed to vitrification solutions, and exceeds the rate of electrical responses in uncooled control slices in many other laboratories. This is the first time electrical activity analogous to a normal electroencephalogram (EEG) response has been achieved in organized brain tissue after cooling to temperatures low enough to achieve vitrification.
Vitrifying the Entire Brain
Like studies of isolated hippocampal slices, studies of entire rabbit brains have found that all regions of the brain appear to be structurally preserved after vitrification and re-warming. Initial studies have shown that it is difficult to preserve the brain’s ability to respond electrically after five hours of cold storage or cold perfusion in the absence of cryoprotectant chemicals. Studies are under way to overcome this problem, however, and the 21CM team will eventually look at electrical activity in brains that have been perfused with vitrifiable concentrations of cryoprotectants. It appears as though the entire brain can be vitrified, but further research is required to see whether normal electrical activity in the brain can be preserved after vitrification.
Vitrifying the Entire Body
When whole rabbits were vitrified, scientists collected tissue samples from many brain and kidney regions as well as from the heart, lungs, liver, intestine, muscle, skin, fat, stomach, and other areas. Using a device called a differential scanning calorimeter, scientists tested the samples to see whether ice formed within them. The differential scanning calorimeter can cool tissue samples to vitrifiable temperatures, warm them up, and measure how much ice has melted during warming. The amount of melted ice is equal to the total amount of ice formed during both cooling and warming, and the temperature at which the ice melts is a measure of how much cryoprotectant was in the tissue before it was cooled.
The results showed that the most difficult tissue to vitrify in the entire body was the center of the kidney, called the inner medulla. Most of the tissue samples showed only small amounts of ice formation, or none at all. Since 21CM is moving toward successful vitrification of whole kidneys, it appears that the entire body can be successfully vitrified as well. This suggests that whole-body suspended animation is an achievable goal, but a great deal of additional research will be necessary to attain this goal.
Living in Good Health for Centuries
Before suspended animation is achieved, the vitrification research funded by Life Extension will lead to banks of well-preserved cells, tissues, and organs for use in transplantation, regeneration, and rejuvenation therapies. One obstacle to the development of these life-extending therapies is that transplanted tissues are currently rejected by the body’s immune system, which requires the lifelong administration of expensive immunosuppressive drugs that have serious side effects. This is why transplantation today is largely reserved for patients whose lives are at stake unless they receive a new heart, liver, or kidney.
However, research in neutralizing the body’s rejection of foreign tissue is now at an advanced stage, and cloning and stem cell research to develop tissues that are not rejected at all is also advancing rapidly. Overcoming the rejection problem and perfecting organ vitrification will mark the dawning of a new era in which the widespread availability of banked, vitrified body parts will be used to keep us alive, healthy, and vigorous . . . perhaps for centuries!
In the scenario that opened this article, you had been placed in suspended animation in 2035 to await the time when advances in science and technology would enable doctors to restore you to life, health, and youth. Based on research now being funded by Life Extension and others, it is possible that you could be revived in a state of physical immortality well before the end of the twenty-first century.