Partial reprogramming

Briefly activating reprogramming genes so a cell sheds signs of ageing without losing its specialised identity.

• Full reprogramming takes weeks and erases identity; short or cyclic pulses aim to stop well before that point.
• In mice it restored vision after optic-nerve damage and, in some studies, extended remaining lifespan.
• Many efforts use three factors (OSK), leaving out the cancer-linked c-MYC; Life Biosciences plans the first human trial, in optic-nerve disease.
• The window between rejuvenation and tumours or organ failure is narrow, and delivery must reach enough cells in a tissue to matter.