I was fascinated by recent the TED talk by Mark Roth: Suspended animation is within our grasp. I’m sure many of you also were wondering about the phenomenon of suspended animation and its possible application in medicine. Because I’m thinking about stem cells 24/7, it was also in my mind when I watched his talk. I was thinking “Wow, seems like he is talking about extreme survival of dormant stem cells in our body!”
2 important points made me think so.
First, a while ago I’ve read some interesting reports about harvesting of human neural stem and progenitor cells from the postmortem brain. At that time I was wondering how brain cells can do extremely well in culture 1-2 days after death. I looked at more literature and found that rodent neural stem cells from brains of different ages can be successfully cultured with postmortem delay of up to 140 hours. The absolute record of extreme survival was described for murine vestibular and cochlear stem cells and it was 10 (!) days postmortem. For human, neural/progenitor cells were successfully isolated from brain 1 day after death and maintained in cell culture up to 40 population doublings until senescence. Also, olfactory stem cells were isolated from cadavers 50 to 95 years old at time of death and successfully propagated in culture up to 70 passages.
The second point is mounting evidence that highly quiescent or dormant populations of adult stem cells exist in special hibernating niches. These stem cells are extremely rare, exist in highly hypoxic conditions, adapted to very low oxygen consumption with a metabolic rate close to zero and transcription program off. The biological meaning of stem cell dormancy is “save life in case of catastrophe”. They get activated and enter into cell cycle only in case of emergency. It’s very reminiscent of suspended animation. Coudn’t the cases of deanimation be explained, at least in part, by priming and boost of dormant stem cell populations in our body?
Now, I’m thinking could dormant stem cells be an example of human cells in suspended animation? And if so, can we learn something from it? For example, how these cells can keep their metabolic rate so low and consume very little oxygen? What signals do they use to achieve this state? And finally, can we use isolated dormant stem cells as a model for study of the suspended animation phenomenon? What do you think?