Pig to rat transplant hailed as breakthrough.

• Position: Nervous System

Cells have been transplanted successfully from one species to another without triggering a rejection response or requiring drugs to suppress the immune system by researchers at Kansas State University, Manhattan. Scientists transplanted umbilical cord matrix (UCM) stem cells from a pig into the brain of a live rat, and for reasons not yet understood, the recipient's immune system did not detect nor reject the foreign cells, which survived for more than six weeks. No drugs were used to alter the immune response.

A subset of the transplanted stem cells responded to the chemical environment of the brain and began to differentiate as nervous system cells. This transition of cell type in a living animal is the first indication that UCM stem cells could be useful therapeutically. "Specifically, the umbilical cord matrix cell source may offer us a basis for treating nervous system disorders like Parkinson's disease," reports neuroscientist Mark Weiss. Developing effective treatments for Parkinson's and other nervous system disorders depends on scientists identifying a source of neural...