Researchers Regrow Mouse Thymus

WIKIMEDIA, RAMAThe thymus, a small immune organ that sits near the heart, shrinks as humans age. Scientists have struck upon a method of getting the thymi of old mice to grow back simply through the overexpression of a transcription factor. The results, published this week (April 8) in Development, represent “the first report of the regeneration of a whole, aged organ by a single factor,” according to a comment from the journal.

In thymic epithelial cells, the research team upregulated a transcription factor called Forkhead box N1 (FOXN1), which had previously been implicated in age-related thymus shrinkage. Consequently, the mouse thymi grew back and started putting out more T cells. The team’s analyses showed that the organs, in appearance and gene expression, resembled those of juvenile mice. Whether the immune system of the mice actually improved, however, is not certain.

“This interesting study suggests that organ regeneration in...