University of Colorado and University of Rochester researchers said they made two types of brain and spinal cord cells called astrocytes from the same embryo-derived precursor cell. Only one type, called GDAsBMP, promoted nerve regeneration and the recovery of limb motion in adult rats when transplanted into the spinal cord at the injury site. The other type of astrocyte cell failed to promote regeneration or functional recovery, and caused pain.

University of Colorado Denver School of Medicine Associate Professor Stephen Davies said, "To our knowledge, this is the first time that two distinct sub-types of astrocyte support cells generated from a common stem cell-like precursor cell have been shown to have robustly different effects when transplanted into the injured adult (rat) nervous system."

Another study co-author, Professor Mark Nobel of the University of Rochester, said, "These studies are particularly exciting in … defining the optimal cell for tissue repair and identifying means by which inadequately characterized approaches may actually cause harm."

The research appears in the Journal of Biology.