Thursday, January 9, 2014

Frozen Human Brains, Stem Cells, and Ice Cream

Signals just posted a short summary I wrote on this paper, where a team at Columbia University and the New York Stem Cell Foundation managed to create iPS cells from human brain tissue that was frozen for 11 years. 

The paper itself is actually a neat example that human cells are pretty resilient, as the team specifically used tissue samples that weren't protected against freezing with glycerol or DMSO, common additives to prevent ice crystals from forming and damaging the cells.

And since stem cells were created from patients with four different neurological diseases, it also means that other kinds of poorly stored samples, not protected with an antifreeze, might be used to make model cells as well. 

Since Signals has the summary of the paper, I'll digress on the topic of antifreezes here.  You might also know that antifreezes aren't just useful for storing biological samples in freezers; many organisms protect themselves from freezing with antifreeze compounds or antifreeze proteins in their own bodies.  

Several antifreeze protein structures.  From RCSB.

Besides keeping organisms alive, antifreeze proteins also have a variety of useful applications for humans (which obviously don't have any), with the best one I know of is the use of fish antifreeze protein as an additive to ice cream.

I first heard of this in a talk by Peter Davies, a scientist at Queen's University, who described how antifreeze proteins were identified in mealworms. He describes some of that work in this short interview at NPR, where he also adds that the proteins were quickly rebranded by companies using the proteins in food:
DAVIES: Unilever, which is a big company in Europe, who make frozen foods like ice cream for example, they have for some time now been putting the antifreeze proteins into especially low-fat ice cream. Now they don't call them antifreeze proteins because the public would, the consumers would be perhaps nervous about the idea of antifreeze being in food. So they actually call them ice structuring proteins.
By whatever name you call them, the proteins are yet another example of something very useful that came out of purely academic research.