It was announced by the Brain Preservation Foundation on February 9th, 2016, that 21st Century Medicine (21CM) has won the Brain Preservation Prize for small mammals. The prize, which has a purse value of just under $27,000, was awarded on the basis of the company’s ability to almost perfectly preserve the ultrastructure of a whole rabbit brain after cooling to and rewarming from a temperature below the glass transition temperature of the vitrified brain.
The demonstration was based on a new technique called “aldehyde-stabilized cryopreservation,” or ASC, in which the brain was first fixed with glutaraldehyde and then perfused with 65% ethylene glycol using a linear gradient similar to what is normally applied for whole organ vitrification experiments on kidneys. The technique also relies on the use of a common laboratory detergent, sodium dodecylsulfate, or SDS, to open up the blood-brain barrier and allow the cryoprotectant to enter the brain without causing brain shrinkage.
ASC was used in this case because a primary objective of the prize was to demonstrate preservation of brain ultrastructure sufficient to establish that the “connectome,” or totality of all brain cell to brain cell synaptic connections, can be preserved for at least 100 years. Fixation is known to preserve ultrastructure very well, but is not necessarily adequate for very long periods of time. By combining fixation with vitrification, time limitations are removed, thus enabling us to win the prize.
The ASC technique was published in Cryobiology in 2015 (see our list of publications here), but independent evaluation by the Brain Preservation Foundation required several months of exacting work before a final conclusion could be drawn about the comprehensiveness of preservation in the submitted brains.
ASC is not a technique for viable brain preservation, but is a tool that can be used by neurobiologists who need to be able to store rare or valuable material for indefinite periods of time. ASC has a significant advantage over embedded brain samples in that rewarming enables brain perfusion with a variety of markers that can trace the anatomical location of many different substances of interest. It is compatible with many other neurobiological techniques and allows a brain preserved in one location to be shared with specialists in other locations, and even to be used for more than one type of assay. But the main attraction is that ASC enables preservation and examination of the entire brain, not just a part of it, with stability comparable to embedding but with accessibility of all brain areas that is impossible to achieve with conventional methods that require embedding.
21CM has also submitted pig brains prepared by the same technique to the Brain Preservation Foundation for evaluation and consideration as an entry for the Large Mammal brain preservation prize, which has an award value of just under $108,000. According to our preliminary analyses as reported in our published open source report on the method, we believe our pig brains are as well preserved as our rabbit brains, so we are hopeful that the Brain Preservation Foundation will validate our initial findings in the near future.
ASC was developed at 21CM by Robert McIntyre, a recent graduate from MIT, and Dr. Gregory M. Fahy, the company’s Chief Scientific Officer, working with a larger team that included surgeons, microscopists, and special advisors. As the lead investigator on the project, Mr. McIntyre refined many key aspects of the fixation and staining methods as well as methods of opening the blood brain barrier and rapidly processing samples to enable the work to proceed quickly. Mr. McIntyre is now employed by a new startup that was founded to pursue refinements and other versions of ASC, including whole brain embedding, and to seek new applications for the technique.
Although ASC has been discussed in the popular press and even by the Brain Preservation Foundation as a new type of cryonics, in which “revival” might be accomplished by destroying a person’s brain and creating a computer simulation of that brain based on the scanning of immense numbers of brain sections to create a comprehensive map of the structure of that person’s brain, 21CM does not endorse these views. Others have suggested that ASC preserved brains might be revived by means of biological repairs carried out with future tools from the field of medical nanotechnology, but we do not endorse this view either. 21CM sought the prize to demonstrate the power of its vitrification technology to reach beyond conventional applications of cryobiology and provide unexpected new tools to mainstream neurobiologists. While 21CM firmly believes in personal choice and respects the views of all honest people, we are not a cryonics company and as such do not endorse any form of cryonics.
|Life Science Industry News|