Highly read on http://www.cell.com up until 13 september 2010

A pancreas has been generated from rat stem cells inside a developing mouse that lacks the ability to produce a functioning pancreas of its own.

Hiromitsu Nakauchi at the University of Tokyo and his colleagues 'disguised' donor rat or mouse stem cells so that they could be introduced into an embryo of the other species, by culturing the cells under specific conditions.

The team used the technique to inject reprogrammed rat stem cells, capable of forming any tissue, into mouse embryos in which a key gene regulating pancreatic development had been deleted. Only a small percentage of the mice born survived into adulthood, but the pancreases of these mice were functional and derived almost completely from the rat cells. The authors say that the method takes us a step closer to whole-organ regeneration and transplantation.

Cell 142, 787–799 (2010)