Stem cells reverse birth defects in the brains of mice

MIT’s Technology Review reports:

By injecting stem cells directly into the brain, scientists have successfully reversed neural birth defects in mice whose mothers were given heroin during pregnancy. Even though most of the transplanted cells did not survive, they induced the brain’s own cells to carry out extensive repairs.

… [T]hey are consistent with an emerging consensus of how adult stem cells perform their many functions through so-called bystander or chaperone effects. Beyond simply generating replacements for damaged cells, stem cells seem to produce signals that spur other cells to carry out normal organ maintenance and initiate damage control.

Interesting stuff, with obvious biomedical applications. As the article discusses, it is somewhat of a paradigm shift to think that instead of cellular replacement all that is needed to solve certain problems is an injection of stem cells. This research lends indirect support to the importance of neurogenesis to many neurological functions.