Recent research shows that blood from young mice fixes the brain in older mice.
Researchers found that older mice, when given transfusion of blood from young mice, reverses age-related impairments in cognitive function and synaptic plasticity in mice.
Exposure of an aged animal to young blood suggest therefore that it counteract and reverse pre-existing effects of brain aging at the molecular, structural, functional and cognitive level.
Would this also work for humans? No research is still done, but it is on the planning.