Where Do We Stand Today?There have been several advancements in cryopreservation and vitrification technologies in the field of frozen embryos and eggs. Since 1983, scientists have performed many successful freezing, storing, and thawing operations which have led to complete in vitro fertilization (IVF) and healthy pregnancies, with no significant abnormalities in the offspring. Scientists have managed to overcome the basic barrier of harmful ice crystal formation. The invention of cryoprotective agents (CPAs) has made it possible to safely and slowly freeze embryos, or vitrify them with higher concentrations of CPAs while guaranteeing safe thawing later when needed. For now, science offers mature technological solutions to cryopreserve cell lines and small human tissues. The next critical stage is to cryopreserve whole organs successfully.
Organ Revival Among MammalsThe most ambitious goal among cryobiologists is to find a way of extending the methods used with small tissues to complete organs, such as the brain. Cryopreserving a whole brain successfully is the next breakthrough that might change the cryonics game forever. The technique used today involves glutaraldehyde, a disinfectant used to chemically fix the brain during vitrification. Professor Magalhaes from Liverpool University claims that glutaraldehyde’s toxicity can kill off all the vitrified brain cells. Yet, scientists believe that nanorobots could be the solution to save the intoxicated cells during organ revival. Although there have been no recent significant developments in the cryopreservation of human organs, scientists have taken some major steps towards reviving animal organs. The latest news on organ cryopreservation came in July 2005; a team of researchers managed to revive a rabbit kidney that was vitrified at -135°C and then successfully transplant it into a living rabbit. The same team from 21th Century Medicine, a cryobiological research company from California, has also shown evidence that slices of rat and rabbit brains can be vitrified and thawed while sustaining functioning neural responses.
Whole Body Experiments On AnimalsThe bad news is that, to date, no whole mammal has ever been cryopreserved and successfully revived. But the good news is that many attempts have been made to progress towards that goal. For instance, scientists have managed to vitrify dogs and monkeys to non-cryogenic temperatures (below 0°C) by replacing their blood with a protective solution and then rewarming and reviving them successfully. Other teams have managed to cryopreserve and revive Nematode worms in liquid nitrogen. Researchers from Biotime Inc. claim to have cooled down baboons to one degree Celsius and successfully revived them. The team applied the company’s flagship product “Hextend” in these trials. Hextend is a substance approved by the FDA as a blood-volume expander that can maintain blood pressure and chemistry after extensive blood loss. Several studies have tested Hextend in a resurrection-like process. They replace the whole blood supply of animals with the substance, cool it down until the animals are “technically” dead, then warm them up again, recirculate the blood, and bring them back to life. Though the FDA has not yet approved the usage of Hextend in human trials, some scientists are already investigating procedures of cooling down emergency patients to protect their vital cells from damage during surgery.
Conclusion: Will cryogenically frozen people ever be revived?Many critics, such as Professor Caplan from New York University, believe that reviving cryogenically preserved people is “too science-fiction(y)” and “not doable.” If we are going to ask “Will Cryonics work?”, we should remind ourselves that before the 1950s, the scientific community didn’t believe in cardiopulmonary resuscitation. Yet, nowadays, CPR techniques are technically bringing thousands of patients back to life, who have been otherwise historically seen as terminally dead. The research on cryopreservation is taking a step forward each day, and the following are a few of the many reasons why one should believe that science can soon achieve significant breakthroughs in reviving cryopreserved patients:
- Cryopreservation and revival is a successful process in many biological specimens.
- Revival of cells, tissues, and mammal organs is advancing with ongoing ambitious trials.
- The development of cryoprotective agents is not concluded, but instead just starting.
- Nanotechnology research might soon provide examples of nanorobots that can repair cellular damage caused by current vitrification procedures.
- The emerging potentials of 3D bioprinting and stem cell tissue regeneration could lead the path to successful cryopreservation and revival of the human brain.