Amy J. Wagers, an investigator at the Joslin Diabetes Center in Boston, and colleagues at Harvard University and the University of Cambridge in England said their findings offer hope that therapeutic strategies aimed at restoring efficient regeneration can be effective in the central nervous system throughout life.
Using a surgical technique, the researchers introduced an experimental demyelinating injury in the spinal cord of an old mouse, creating small areas of myelin loss, and then exposed those areas to cells found in the blood of a young mouse. Myelin is a fatty substance that protects nerves and aids in the quick transmission of signals between nerve cells.
The researchers found the influx of certain immune cells -- macrophages -- from the young mouse helped resident stem cells restore effective remyelination in the old mouse's spinal cord.
This "rejuvenating" effect of young immune cells was mediated, in part, by the greater efficiency of the young cells in clearing away myelin debris created by the demyelinating injury, Wagers said.
This could be particularly useful, Wagers added, in treating MS, which typically spans many decades of life, and is likely to be influenced by age-dependent reductions in the ability of myelin to regenerate.
The findings were published in the journal Cell Stem Cell.