Summary: The Wistar Institute has found that MRL mice regenerate removed tissue completely with no scar tissue formation. This apparently works for all tissues except the brain. Implantation of MRL mice cells in normal mice confers the ability as well.
Press Release from the Wistar Institute (http://www.wistar.org/news_info/pres...pr_8.9.01.html): There is little or no evidence of scarring in the healed tissue. "Similar injuries to the heart tissue of control mice, for example, showed that only 1 to 3 percent of the heart cells in the region of the injury were capable of dividing. In the MRL mice, however, up to 20 percent of the heart cells divided in response to injury." Research is currently investigating genetic differences between MRL and normal mice.
Now, if that could be applied to humans...