Mar 17, 2016
Tissue regeneration therapies in mammals is progressing at an impressive pace. Everyone who's ever looked into the field knows that vertebrates lower on the evolutionary ladder are capable of regrowing lost limbs and organs, like salamanders and axolotls, but higher lifeforms really can't. The best that humans can do is putting things back more or less they way they were, a process that we all know as healing. Once something's gone, though, it's gone (save for the liver, which can infact regrow if a small portion of liver tissue remains and the rest of the body is properly cared for). That's a long way off from regenerating the last joint of a human middle finger using extracts from pig bladders, though.
So far it's been tried and worked twice, on one Lee Spievack, who lost his finger in an accident involving a benched model airplane, and once on a neighbor of Alan Spievack (founder of ACell, a company that researches and manufactures the tissue regeneration compound). In both cases, the severed portion of finger regrew completely in four to six weeks, is fully usable, and has full sensation. The FDA signed off on it a while ago, and it's been in veterinary use for a while now to treat injured racehoses, so it's not exactly a new technology, just one that isn't in full use yet.
The thing is, they're not entirely sure how it works. The proteins inside the powder that are biologically active tell cells to start dividing and re-expressing the genes that would follow next, morphologically speaking, but the specifics still elude them. Their best hypothesis at this time is that the compounds tells the body to put things back the way they were without any specific commands ("do what I mean," in other words).
This is definitely something to keep a close eye on.