A daily jab of a bone hormone could reverse memory loss, offering hope for millions of older people who struggle with the cognitive problem as they age.
The amount of osteocalcin – a hormone produced by bone cells – we have in our bodies naturally declines as we age, beginning from age 30 in women and 50 in men.
Now it has been found memory loss can be restored by bringing levels back to when we were young.
Researchers said because it is naturally produced by the body an injection of osteocalcin would be safe.
Scientists say memory loss can be reversed by restoring levels of a bone hormone back to youthful levels (file photo)
Professor Gerard Karsenty from Columbia University Medical Centre in New York said: ‘In previous studies, we found that osteocalcin plays multiple roles in the body, including a role in memory.
‘We also observed that the hormone declines precipitously in humans during early adulthood.
‘That raised an important question: Could memory loss be reversed by restoring this hormone back to youthful levels?
‘The answer, at least in mice, is yes, suggesting that we’ve opened a new avenue of research into the regulation of behaviour by peripheral hormones.’
How the research was carried out
Older mice were given continuous infusions of osteocalcin over a two-month period. This was found to greatly improve their performance on two different memory tests, with the old mice reaching levels seen only in young mice.
The same improvements were seen when blood plasma from young mice, which is rich in osteocalcin, was injected into aged mice.
In contrast, there was no memory improvement when plasma from young, osteocalcin-deficient mice was given to aged mice.
But adding osteocalcin to this plasma before injecting it into the aged mice resulted in memory improvement.
The researchers also injected antibodies in young mice to deplete the hormone from their plasma which was found to reduce their performance on memory tests.
No toxic side effects
The team also say they figured out the way in which this works.
They found the hormone binds to a receptor in the brain called Gpr158 in the hippocampus, known as the ‘memory centre’.
This was confirmed by inactivating this receptor mice, and then giving them infusions of osteocalcin, which failed to improve their performance on memory tests.
This finding paves the way for a novel approach to treating age-related cognitive decline in a safe way, say the scientists.
Professor Karsenty said there were no toxic side effects and added: ‘It’s a natural part of our body, so it should be safe.
‘But of course, we need to more research to translate our findings into clinical use for humans.’
Previous work by the genetics expert found the hormone jabs also rejuvenate the muscles of older mice, allowing them to match the running speeds and distances of young mice.
The new study was published in the Journal of Experimental Medicine.