The human body will regenerate it's liver if no more than about 70% has been severed. As far as I know this is the only organ we are capable of doing this.

that is so cool

I would like to see a time lapse video of the regrowing process. it could be quite interesting.

Pigs and humans are a close match,biologically speaking. Do we have 'extra-cellular matrix" in our bladder lining?

Why doesnt our body do this already? It doesnt benifit the body not to be hole, i just cant believe that throughout evolution, something as useful as a regenative body didnt come in. Or are there some sort of side-effects associated with it or dangers to the body?

It is already (not well) known that a finger will regrow naturally if the 2 following conditions are present:
1: There is no stitches
2: The cut goes no farther than the 1st articulation

(Read in Scientific American, march 17th, 2008)

"Why doesnt our body do this already?" Because after ore ancestor had his arm bitten off by that T-rex it clotted up scabbed over and scared up and we got over it. But the lizard people spent so much time growing back new limbs that they forgot to have children. Its a good thing too, because lizard people could lay 10,000 eggs a year; we'd really be having a food shortage if they were still around.

that is very cool.

It sounds as if a lot of you are interested in limb regenertion, so let me get into the details.

We have learned from salamanders a lot about limb regeneration. If we applied what they do, then we would have to first have our fibroblasts go to the wound, then have nerves give signals for cell differentiation and proliferation in the first week after the amputation, maybe more or less because we are not salamanders.
Normally we would then just have epidermal cells covering the wound and eventually a scar would form. Instead, we would need to make a blastema, and make our fibroblast cells give more signals. This would eventually form a limb pattern and the new limb would begin growing.
In a salamander, this whole process takes around 55 days, though I would'nt be surprised if it took longer for a human.

The protein powder used by this man probably helped because the protein might have acted as a scaffold for regrowing tissues. It would also be important to learn how to block fibrosis. This could be applied to helping to regow limbs as well.