Scientists have reversed memory and learning problems in aged mice with infusions of a protein found in human umbilical cord blood.

The striking results have raised hopes for a treatment that staves off mental decline in old age, but researchers stressed that more studies, including human trials, are needed before the therapy can be considered for clinical use.



Tests on frail rodents found that the protein therapy rejuvenated an area of the brain called the hippocampus, which is crucial for memory formation, and one of the first and most important regions to deteriorate in old age.



Older mice that received the treatment reacted like younger animals in a series of behavioural tests, according to researchers at Stanford University in California. They escaped from a maze faster than before, had better memories, and started building nests again, a skill the animals tend to lose in old age.



Researchers led by Tony Wyss-Coray made the discovery after they noticed that human umbilical cord blood had unusually high levels of a protein called TIMP2 when compared with blood from older people. When injected into mice, the protein ramped up the activity of a group of genes that revitalised the hippocampus, and made it more able to adapt to new information. Details of the study are reported in Nature.



The work is the latest in a string of studies that suggest molecules found in young blood may be able to rejuvenate old brains and other tissues. If the therapies are effective in humans, they could become a potent weapon against the cognitive decline that comes with old age, and also neurodegenerative diseases such as Alzheimer’s.



But until the treatment has proved itself in humans, scientists are roundly cautious of the work. The lesson from Alzheimer’s research on mice is that almost everything works in the animals, and so far nothing works in humans, said Rob Howard, professor of old age psychiatry at University College London. “Having taken that on on board, this is a really interesting way to understand how we might help people who are aged or in the early stages of the disease,” he said. The protein therapy might not reverse brain ageing, or halt Alzheimer’s, but it might boost what remains of the healthy brain to at least offset some of the decline that accompanies old age.



Jennifer Wild, a clinical psychologist at Oxford University, said that while the results were interesting, it was too early to consider it as a therapy for humans. “It’s exciting for mice who have cognitive ageing, but it’s way too early to start extrapolating that to say we can help humans,”, she said.