A molecule that accumulates in the blood with age may be linked to cognitive decline, say scientists who mooted hopes of a memory-restoring treatment.
The protein, dubbed B2M, is found in higher concentrations in the blood and cerebral spinal fluid of ageing humans, they say. And in mice, lowering B2M improved learning and memory in lab experiments.
â€œWe are very excited about the findings because it indicates that there are two ways to potentially reverse age-related cognitive impairments,â€ says study co-author Saul Villeda of the University of California San Francisco.
â€œOne is to introduce pro-youthful blood factors and the other is to therapeutically target pro-ageing factorsâ€ like B2M, he says.
Villeda had participated in another study, published last year, which found that injections of juvenile mouse blood boosted learning and memory in older rodents. Scientists measure the animalsâ€™ ability to remember cues indicating the position of hidden platforms in water, similar to having to recall physical landmarks to remember where you left your car in a parking lot â€“ a function that declines with age.
Old mice who received young blood in the first study could find the hidden platforms easier â€“ though it was not clear why or how. Ageing is associated with a progressive decline in cognitive function, and slower regeneration of message-relaying neurons in the brain.
â€œAgeing remains the most dominant risk factor for dementia-related neurodegenerative diseases, such as Alzheimerâ€™s disease,â€ write the authors of the new research published in the journal Nature Medicine.
â€œAs such, it is imperative to gain mechanistic insight into what drives ageingâ€¦ in the brain in order to counteract vulnerability to cognitive dysfunction.â€
From the latest work, it appears that B2M, a protein involved in immunity, may help explain the young blood effect on memory.
B2M injections impaired the learning ability, memory, and neuron growth of lab mice, the team write. But the effect was â€œreversibleâ€ by stopping the injections.
In another experiment, the scientists eliminated B2M genetically in mice, and â€œobserved that the old mice lacking B2M did not develop memory loss,â€ says Villeda.
This all implied the molecule â€œcould be targeted to potentially restore cognitive ability in the elderly,â€ he adds.
The next step would be to develop a molecule that can either block the protein, or help remove it from old human blood.
B2M has previously also been found in elevated levels in the cerebral spinal fluid of dementia patients. â€“ AFP Relaxnews