Alzheimer's could be caused by a 'dirty brain' - and a common drug may 'clean' your mind

Alzheimer's disease could be treated by a drug we've already used for decades, according to new research. 

Researchers found a type of drug used induce labor in pregnant women also speeds up the system that clears waste from the brain, which is dysfunctional in the people.

This is why some call Alzheimer's, and other dementias, 'dirty brain' diseases, since when the disposal system slows down, toxic waste builds up in the brain, crowding and damaging healthy tissue. 

Applying drugs which cause muscle contractions can restore some of that function, said Dr Douglas Kelley, a professor of mechanical engineering at the University of Rochester, who led the study.

These kinds of drugs, used to help deliver over a million pregnancies per year, can be taken as a pill, IV or applied as a topical for $561. 

'This research shows that restoring cervical lymph vessel function can substantially rescue the slower removal of waste from the brain associated with age,' Dr Kelley said. 

'Moreover, this was accomplished with a drug already being used clinically, offering a potential treatment strategy.' 

The study, which was posted in the journal Nature Aging, looked at the complex series of tunnels and pumps that the brain uses to remove waste called the glymphatic system. 

The system pumps fluid over the brain's tissue, washing away and pumping out old cells and proteins that could gunk up and harm neurons. 

In a young and healthy brain, this system is well-oiled and efficient. But it slows down as we age or develop dementia.

One theory for Alzheimer's is that this slowing allows the build up of proteins called beta amyloid. 

Beta amyloid is a naturally occurring protein, that in young brains, gets processed when its no longer useful and shipped out to the body to be processed.

But in Alzheimer's, bundles of these dysfunctional proteins can build up, a hallmark of the disease, crowding out and killing healthy brain tissue.

A similar process happens with a different protein called alpha-synuclein in Parkinson's. 

Dr Kelley was able to observe how the brains waste systems slows with age in mice by marking the pumps in their brains and recording them work. 

He found that in young, healthy mice, these pumps were working quickly, delivering a near-constant flow of dirty fluid out of the brain. 

But in older mice, the contractions slowed by about 63 percent, letting more 'dirt' pile up in the brain. 

Seeing this delayed pumping led the researchers to consider a type of drug that's been used for years, called prostanoids. 

Prostanoids are drugs that affect prostaglandins, a type of fat that your body makes naturally that causes muscle contractions, amongst other things.

These medications are useful in a wide range of medical situations - from helping induce muscle contractions in labor, to treating glaucoma to altering blood flow. 

They were used to deliver about 31 percent of American babies in 2020 - helping bring 1,117,612 new people into the world for around $561 per dose. 

Perhaps the most famous of these is misoprostol, one of two drugs used in a medication abortion. 

The researchers applied a kind of topical prostanoid medication on the mice's necks, right above the pumps that process the brains waste. The theory was that this could cause the muscles in the pumps to power back up. 

The drug sped the older mice's pumps back up - making them as efficient as the young, healthy mice at removing old fluid from the brain.

 'One can see how this approach, perhaps combined with other interventions, could be the basis for future therapies for these diseases,' Dr Kelley said.