Towards Reversible Cryopreservation of Organs

There is a fairly strong connection between the small cryonics industry, focused on preserving the human mind following death in order to offer a chance at renewed life in a more technologically capable future, and present efforts to reversibly cryopreserve organs. The technologies used are much the same, and there is a fair degree of overlap in the people involved and the sources of funding. To my eyes success in organ cryopreservation, and consequent growth of an industry focused on making the logistics of transplantation and near future creation of new organs much easier, is the most plausible path to greater public acceptance of cryonics. When livers and hearts can be reliably vitrified, stored for years, and restored as needed, then it isn't a leap to understand that, with further progress and suitable techniques, this could be done for the brain as well.

Over the course of an average winter North American wood frogs, Rana sylvatica, may freeze solid several times. They are able to get away with this by replacing most of the water in their bodies with glucose mobilised from stores in their livers. That stops ice forming in their tissues as temperatures drop. When things warm up again, the frogsicles thaw out, with no evident ill effects. What frogs do without thinking, human researchers are trying, with a great deal of thinking, to replicate. The prize is not the freezing and reanimation of entire people but the long-term preservation of organs for transplant.

According to the World Health Organisation, less than 10% of humanity's need for transplantable organs is being met. The supply has fallen as cars have become safer and intensive-care procedures more effective, and part of what supply there is is lost for want of an instantly available recipient. Cooled, but not frozen, a donated kidney might last 12 hours. A donated heart cannot manage even that span. If organs could be frozen and then thawed without damage, all this would change. Proper organ banks could be established. No organs would be wasted. And transplants that matched a patient's requirements precisely could be picked off the shelf as needed. The problem is that water expands when it freezes. If that water is in living tissue, it does all sorts of damage in the process. But an alliance of experts, ranging from surgeons and biochemists to mechanical engineers and food scientists, is attempting to overcome this inconvenient fact. And, after years of labour, many of them think they are on the threshold of success, and that cryopreservation will soon become a valuable technology.

There are in fact many cryopreservationist ideas around - so many that some think a little co-ordination is in order. That is the purpose behind the Organ Preservation Alliance (OPA), an American charity. Last year it persuaded America's defence department, an organisation with an obvious interest in transplants, to seed seven cryopreservation-research teams with money. The XPRIZE Foundation is considering offering an award to any team that can transplant into five animals organs that have been cryopreserved for a week. The research-funding arm of the Thiel Foundation has given a grant to Arigos Biomedical, a firm working on high-pressure vitrification. New firms abound: Tissue Testing Technologies is working on ways of warming organs uniformly; Sylvatica Biotech is perfecting recipes for cryoprotectants; X-therma is attempting to mimic cryoprotective proteins. The cryopreservation race is on, then. And the winning post is the organ bank.