WE’VE DISCUSSED THIS BEFORE: Blood May Hold the Key to Reversing Aging. “First, the team used a heterochronic parabiosis mouse model, in which the blood vessels of a young mouse were connected to an older mouse, so they shared blood circulation. While the older mouse slowed its pace of aging when connected, the younger mouse aged more quickly. ‘When we separate them and remove the old circulation,’ White said, ‘the young mouse is able to reverse that accelerated aging and go back to its chronological age.'”