2007-05-24

Conference: Advances in Human Cryopreservation, May 18-20, 2007 Ft. Lauderdale, Florida, U.S.A.


The conference was a wonderful opportunity to meet people involved in life extension and hear about the latest research. It truly is amazing, the dedication and persistence of people like Saul Kent, who has been involved since the 1960s I believe and who has contributed so much money to the effort, and people like Greg Fahy, who has been working on organ models of vitrification for over three decades. Some people, like Mike Darwin, seem to have spent their entire lives on this work. I am going to try to give my view of what happened at the conference and then follow with some reflections of my own on the issues raised.

Notes Part 1 of 4

Note: These are just my summaries from my notes. As a layperson with bad handwriting and poor memory, I am sure I will have introduced errors that are not to be attributed to the speakers! Blame me not them if something is wrong or doesn’t make sense…

Saturday morning, Charles Platt introduced the company, Suspended Animation (SA), of which he was Director until recently. SA focuses on standby, stabilization, and transport, with an emphasis on rapid intervention. SA does not house patients.

SA places the patient in an ice bath -- a vinyl-lined, wheeled stainless steel gurney. Ice water is circulated along the face and stomach by a submersible pump through plastic tubing. A mechanical "thumper" provides cardiopulmonary support. In the specially designed transport vehicle or a mortuary prep room, blood is removed and replaced with chilled perfusate.

Next Steve Harris, M.D., of Critical Care Research spoke about breakthroughs in rapid cooling of patients. In the 1980s, Peter Safar began studying the benefits of hypothermia using dogs. After human clinical trials published in 2002 showed double the survival rate, health providers have begun to induce hypothermia in victims of stroke or heart attack or other severe injury. This mild hypothermia helps to protect the brain and improve its prospects for recovery. This practice has caught on now only in hospitals in larger cities. Smaller hospital ICUs either use only an ice pack or provide no hypothermia.

Critical Care Research in southern California (funded by Life Extension Foundation), has been studying resuscitation from cardiac arrest in a dog model. The heart can be restarted after an hour if it is cooled to 18 degrees C., thus it is certainly not dead immediately. Neurons can also be resuscitated for a long time before apoptosis (self-destruction). They are not really alive; metabolism stops. But they are also not really dead!

Steve showed a photo of "Bob the Dog", who was clinically dead from cardiac arrest for 15 minutes, at room temperature. Afterwards, Bob was healthy and happy, and survived for many years.

According to Steve, the human body treats all injuries as -minor-, -penetrative-, and -infected- injuries, because historically those were the only injuries which animals could survive, and thus our bodies have evolved to handle such injuries. The body's injury response is thus -not- "intelligent". The body sends in white blood cells and does other things which may be counter-productive after cardiac arrest or similar major traumas. Protecting the brain with hypothermia may be compared to putting ice on a sprained ankle.

Many drugs have been investigated which can help protect the heart after arrest, but no drug is known to help protect the brain in recovery from insult. Some drugs have being studied in clinical trials, but so far they have been found to give little benefit in isolation. Each one contributes only a small effect since it targets only one small component of the body's maladaptive response. The Critical Care Research drug cocktail recommended for biostasis has not changed since the late 1990s, and derives from the dog studies.

Critical Care Research is exploring liquid ventillation to induce fast and easy cooling. In liquid ventillation, cold perfluorocarbon is pumped into the lungs. The brain can be cooled 7 degrees in 18 minutes with liquid ventillation. Liquid ventillation, or "lung lavage". is the fastest method of cooling down to 2 degrees C without damage. The lung lavage is synchonized with CPS breaths and requires only a small amount of perfluorocarbon.

In response to questions, it was stressed that bystanders should not attempt any action, even ice packs or cardiopulmonary support or locating heparin, until death has been pronounced and the coroner has signed off on the death. Otherwise, the bystander may create circumstances which call for an autopsy, and the autopsy will in turn severely compromise the patient's biostasis.

The Zoll AutoPulse is now replacing the Thumper -- it has a strap which fits across the entire upper body; it is battery-operated, quiet, and is being adapted for contact with water. CPS returns -warm- blood to the brain, reducing the cooling from ice water on the head: that is why liquid ventillation is helpful.

Next, Greg Fahy, of Twenty-First Century Medicine (21CM) talked about his unpublished 2007 research, partly funded by an NIH grant, to use vitrification to preserve corneas for transplantation after long-distance transport. Vitrified corneas transplanted with better results than unvitrified corneas in a monkey model.

Then he discussed his work with vitrifying rabbit kidneys. Kidneys were cooled to -45 degrees C and transplanted –in vivo-. But ice formed in the center (medulla) of the kidneys, apparently due to insufficient perfusion to this area which is relatively isolated in circulation. In addition, at 45 days’ vitrification, there was damage to one side of the kidney surface, damage Greg has named ‘surface viscoelastic injury (SVI). Greg speculated that SVI (apparently a kind of hemorrhage) might be caused by simultaneous stiffening and shrinking of the tissue there (analogous to the cracking problem at liquid nitrogen temperatures), and that different –loading techniques- (for perfusion) might affect SVI.

Greg also updated us on the study of the vitrified and thawed rat hippocampal slices. Looking for the ability to display electrical activity, he found 70% neural firing at up to 45 days, about the same as would be found in slices that had not been vitrified. He thus concludes that vitrification has no effect on neural firing or viability.

He also tested the ability of such slices to retain long-term potentiation (LTP) patterns after vitrification and rewarming, finding that the “memory response” did persist.

However, he reminded the audience that there has never been a demonstration of brain resuscitation after more than 3 hours of static cold storage, and that continuous hypothermic perfusion with good solutions was necessary to raise the time to even 4-6 hours. He has conducted 250 brain experiments since 2003, and that even with only 50% M22 (really poor perfusion with the cryoprotectant solution), still no ice foms in the brain. For some reason, the brains vitrify even though that percent solution would not vitrify in a test tube.

Shrinkage of the brain is governed by laws of osmosis (Boyle-van’t Hoff Plot). Greg asserts that brain shrinkage may be “more friend than foe,” although one supposes there must be a minimum safe cell volume. Tests with putting cryoprotectant through the blood-brain barrier (BBB), which it normally does not penetrate, actually leads to –worse- results for the brain. For some reason, M22 washout itself seems to cause significant brain damage (analogous to SVI?).