As Miracle Max (Billy Crystal) explained in Rob Reiner’s 80s classic, The Princess Bride, “There’s a big difference between mostly dead and all dead. Mostly dead is slightly alive.” Shahragim Tajbakhsh of the Pasteur Institute recently stopped by to present his work on skeletal muscle stem cells (for quick primer on what stem cells are, here is a short animated clip narrated by their co-discoverer, Dr James Till). Dr Tajbakhsh presented some first-rate work on how gene regulatory networks specify cell fates.
Then things got weird. Dr Tajbakhsh showed data obtained together with Mathilde Latil, Fabrice Chrétien and five other collaborators. They set out to find the border between “mostly dead” and “all dead” for skeletal muscle stem cells. The results are incredible. The team was able to recover and grow viable stem cells, capable of generating living muscle tissue, from cadavers as old as 17 days post-mortem. In fact, we still don’t know where “all dead” begins, as the experiment ended at day 17 due to a legal requirement for burial.
While this may seem like a macabre exercise, Latil et al present very promising data in an area in dire need of progress: the recovery of viable human tissues that can be used for transplantation. Knowing which tissues survive and for how long is a key parameter. Tissue specific stem cells are also a viable source of raw material for regeneration or transplantation, and this paper gives us an important clue on how to maintain them viable long after donor death (the key component, besides refrigeration, is very low oxygen levels- the hypoxia seems to trigger a cellular hibernation program).