Scientists hope they have found a drug to stop all neurodegenerative brain diseases, including dementia.
In 2013, a UK Medical Research Council team stopped brain cells dying in an animal for the first time, creating headline news around the world.
But the compound used was unsuitable for people, as it caused organ damage.
Now two drugs have been found that should have the same protective effect on the brain and are already safely used in people.
“It’s really exciting,” said Prof Giovanna Mallucci, from the MRC Toxicology Unit in Leicester.
She wants to start human clinical trials on dementia patients soon and expects to know whether the drugs work within two to three years.
Why might they work?
The novel approach is focused on the natural defence mechanisms built into brain cells.
When a virus hijacks a brain cell it leads to a build-up of viral proteins.
Cells respond by shutting down nearly all protein production in order to halt the virus’s spread.
Many neurodegenerative diseases involve the production of faulty proteins that activate the same defences, but with more severe consequences.
The brain cells shut down production for so long that they eventually starve themselves to death.
This process, repeated in neurons throughout the brain, can destroy movement, memory or even kill, depending on the disease.
It is thought to take place in many forms of neurodegeneration, so safely disrupting it could treat a wide range of diseases.
In the initial study, the researchers used a compound that prevented the defence mechanism from kicking in.
It halted the progress of prion disease in mice – the first time any neurodegenerative disease had been halted in any animal.
Further studies showed the approach could halt a range of degenerative diseases.
The findings were described as a “turning point” for the field even though the compound was toxic to the pancreas.