Reversible cryopreservation

On the forum of the Immortality Institute there is an interesting exchange about the feasibility and time line for reversible cryopreservation. Cryobiologist Brian Wowk weighs in with some interesting observations:

I think in the next 20 years more small animal organs, and perhaps some human organs, may be reversibly cryopreserved. The best scenario for cryonics would be improved, and possibly demonstrably reversible, cryopreservation of animal brains. It has been long observed that if reversible solid-state brain preservation could be demonstrated, then cryonics revival becomes a purely technical problem (albeit very complex one) of tissue regeneration. There would be no remaining doubt about whether the preservation itself was viably preserving human beings….Reversible solid-state cryopreservation of whole mammals is a very difficult problem with existing technology. This is why when asked about it people will often defer to nanotechnology. References to nanotechnology as a solution to a medical problem basically say, “We have no idea how to solve this problem with existing tools, but future abilities to completely analyze and repair tissue at the molecular level will be implicitly sufficient.” It’s a valid argument, but saying that a medical problem will be solved when someday technology exists to solve *every* medical problem is not very illuminating about time lines or nature of the problem.

Advocates of cryonics often push for demonstration of reversible small animal cryopreservation as  a means to persuade the medical establishment and the general public of the technical feasibility of cryonics. The limitation of this approach, however, is that this goal cannot be achieved until we are able to successfully vitrify all vital organs of the animal, including such difficult organs  as the lungs and the kidney. A more promising approach is to keep improving vitrification of the central nervous system. As argued in a recent piece for Alcor’s Cryonics Magazine, if organized electrical activity can be demonstrated after whole brain cryopreservation a strong case can be made for the acceptance of cryonics as a medical procedure and improved legal protection of cryonics patients.  It should be noted, however, that these research efforts constitute only one objective in cryonics. Another objective of cryonics research is to optimize procedures and protocols for existing patients, who invariably suffer some degree of circulatory arrest.

Armand Karow on Isamu Suda's brain cryopreservation experiments

In 2007, cryobiologist Armand M. Karow passed away. Unlike many contemporary cryobiologists, Karow offered cautious support for the objectives of cryonics. In the mid-1960s, Karow served on the Scientific Advisory Council of the Cryonics Societies of America (CSA). He also published a regular column titled “Scientifically Speaking” in Cryonics Reports, a publication by the Cryonics Society of New York (CSNY).

One of these columns, “The Suda Experiment,” contains his comments on   Isamu Suda’s cat brain experiments. Suda perfused whole cat brains with low concentrations of glycerol and recorded electrical brain wave activity (EEG) after storage at high subzero temperatures and rewarming. But as Karow points out, “the generation of EEG’s is not necessarily an indication of organized, coherent activity… The EEG tracings obtained by Suda probably could have been generated even if a large number of the cells were damaged.”

A similar point can be made about studies that demonstrate viability in brain tissue after long periods  (1 hour) of warm ischemia. Although such studies are helpful to persuade critics of cryonics that cryopreservation or warm ischemia do not (instantly) destroy the brain, there is a tendency in cryonics to selectively highlight studies that are “outliers” in their field to make the case for cryonics. A related issue is the scientific meliorism implicit in the view that whatever can be imagined as not contradicting the laws of chemistry and physics will occur, a view of which the scientific, psychological, and social  aspects will be discussed here in more detail in the future.

Armand Karow – The Suda experiment (Cryonics Reports, 1967)

Cryobiologist Brian Wowk on the Suda experiments and cryonics (Immortality Institute Forum, 2006)