Irish scientists have made a major breakthrough in relation to the most common form of dementia worldwide, Alzheimer's disease.

According to the team from Trinity College Dublin (TCD), their findings could lead to the development of new forms of therapy for those affected.

Alzheimer's disease affects around 40,000 people in Ireland. It is the fourth leading cause of death in those over the age of 65.

While memory loss is probably the most well-known symptom, other symptoms can include changes in mood, changes in personality and difficulty performing familiar tasks.

The breakthrough made by the TCD scientists relates to how a specific protein is cleared across the blood brain barrier.

During Alzheimer's disease, there is a build-up of a protein in the brain known as amyloid-beta. Impaired clearance of this protein seems to play a major role in the build-up of plaques and then in the development of the disease itself.

While it is not known how amyloid-beta is cleared, it is accepted that it does need to be removed from the brain via the bloodstream.

Blood vessels in the brain have specific properties that regulate what gets in and out of the brain. This is known as the blood-brain barrier (BBB) and no other blood vessels in the body are capable of this.

"We have shown that distinct components of these blood vessels, termed tight junctions, are altered in Alzheimer's disease. We think that this alteration could be an entrained mechanism to allow for the clearance of toxic amyloid-beta from the brain in those living with Alzheimer's disease," explained Dr James Keaney, a postdoctoral researcher in TCD's School of Genetics and Microbiology.

The study involved examining the brain tissues of people who had been affected by Alzheimer's when they were alive.

"Our recent findings have highlighted the importance of understanding diseases at the molecular level. The concept of periodic clearance of brain amyloid-beta across the BBB could hold tremendous potential for Alzheimer's patients in the future. The next steps are to consider how this might be achieved.

"Given the recent advances in clinical trials of anti-amyloid beta antibodies, we hope our findings may lead to improved and adjunctive forms of therapy for this devastating condition," noted Dr Matthew Campbell, a research assistant professor in genetics at TCD.

Details of these findings are published in the journal, Science Advances.

For more information on Alzheimer's disease, see our Alzheimer's Clinic here