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Friday, March 10, 2006

Tom Rando's awesome talk

Tom Rando gave last Wednesday's Frontiers talk and it was really good. He works on muscle growth and regeneration and the title of the talk was "Aging, stem cells, and the challenge of senescent tissue repair". Aging and stem cells -- double sexy based on the title alone, but the content was even better.

I am not going to summarize the presentation in detail, but will list three of the coolest things I learned during it. First, apparently, one can do parabiotic experiments, which involves connecting two organisms subcutaneously. After a while (days or weeks), the vessels of the two organisms find each other and they start merging their circulatory systems. In Rando's experiments they attached mice from different age groups and studied the effects of young blood on old mice and vice versa. What they found (this is the second cool thing) is that stem cells that are responsible for muscle regeneration after injury are present and are totally fine in the old mice. It's just that the younger mice have some kind of a factor in their blood serum that stimulates the stem cell activation, while the old mice appear to be saddled with inhibitors. Joining a young mouse with an old one restored muscle regeneration in the old mouse completely. They also did some in vitro experiments to further understand what's going on. Pretty neat.

The last thing that kind of blew my mind, was this idea first proposed by Cairns in 1979, that through successive rounds of DNA replication the organism remembers which strands are the original ones and which ones are copies. These template strands are segregated together and find themselves in the same cells. This allows the organism to preserve the original code and withstand the mutational load in tissues with a lot of regeneration (most errors come about as a result of synthesis). It seems like initially no one could find any support for this hypothesis, but now Rando and others have presented some pretty convincing evidence based on DNA labeling experiments. I guess you needed to know where too look -- stem cells are the ones that carry the template DNA and there aren't that many of them relatively speaking.

While I don't know if there is anything informatics-related in what Tom Rando does but he is at Stanford, and is doing some of the coolest work around.


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