Scientists investigate leaky brain barriers and dementia

A new theory about the cause of dementia has been developed between scientists at the University of California in the US and Ben-Gurion University of the Negev in Israel. It has led to the formation of an alternative drug that is thought to have the potential to reverse the neurodegenerative condition.

The blood-brain barrier is a dense wall of cells and blood vessels that has the important job of protecting the brain from foreign elements in the bloodstream. It stops them from reaching the neurons, which perform a crucial role in transmitting information to other cells.

It has long been known that the death of brain cells contributes to dementia, but these twin studies suggest it could be connected to leakages in the blood-brain barrier. With harmful substances not being prevented from entering the brain, they could be killing off brain cells and bringing about an ‘inflammatory fog’.

This could help to explain why dementia tends to affect more elderly people, as the barrier wears thin with age. After this was discovered by scientists in Israel, a chemist in California created a drug that could pass through the barrier and potentially restore brain cell function.

Previous research into dementia has focused on amyloid beta proteins in the brain, but this approach has not led to any drugs coming to market to reverse the condition. With projections for the future suggesting the number of people who will suffer from dementia will increase dramatically, alternative avenues of investigation are being sought.

In conducting such research, Dr Alon Friedman of Ben-Gurion University found that nearly 60 per cent of over-70s have a leaky blood-brain barrier. Such high numbers warrant a closer look and could provide the breakthrough required to find an effective cure.

Dr Friedman and UC Berkeley's Dr Daniela Kaufer are encouraging people to think about the processes leading to dementia in a different way. Leaks instead of proteins could be the future of research in the field.

Dr Kaufer said: “We tend to think about the aged brain in the same way we think about neurodegeneration: Age involves loss of function and dead cells. But our new data tells a different story about why the aged brain is not functioning well: It is because of this ‘fog’ of inflammatory load.

“We now have two biomarkers that tell you exactly where the blood-brain barrier is leaking, so you can select patients for treatment and make decisions about how long you give the drug. You can follow them, and when the blood-brain barrier is healed, you no longer need the drug.”

The team discovered that the blood molecule albumin had a particularly devastating impact on the TGF-beta receptor when it leaked into the brain. To prevent it being poisoned, the receptor can be blocked, stopping the albumin from having any impact.

In order to do this, the drug must be so small it can pass through the usually impenetrable blood-brain barrier. A scientist in Palo Alto, California has achieved this and while more testing needs to be carried out, it could be a big step forward in treating dementia.