Dementia is common to a variety of neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and Down syndrome (DS). This characteristic symptom is one of the significant causes of disability and dependency among older people. Worldwide, around 50 million people have dementia, and there are nearly 10 million new cases every year.

Now, a group of European scientists aims at identifying the common physiological pathways between the different diseases involving neurodegeneration and dementia, in an area of ??the brain stem called locus coeruleus. Their research could be helpful to determine new biomarkers of dementia progression and to explore new therapeutic approaches.

The HEROES project (tHE cRossroad of dEmentia Syndromes) is a 3-year, € 1.3m project funded by the European Joint Program Neurodegenerative Disease (JPND). JPND Research is the largest European global research initiative aimed at tackling the challenge of neurodegenerative diseases. 

Center For Genomic Regulation

According to project coordinator Dr. Mara Dierssen, group leader at the Center for Genomic Regulation (CRG) and research collaborator at Hospital del Mar Research Institute (IMIM) in Barcelona, ??Spain: "All three of these conditions go hand in hand with evolutionary dementia, which – on the clinical level – in turn, leads to difficulties with attention, memory, and alertness.

These functions are controlled by neurons (brain cells) in a small structure of the brain stem called the locus coeruleus, a region which produces about 90% of all the brain's available noradrenaline.

We believe that common factors are leading to the early loss of cells and their function in the locus coeruleus, implying that the origin for these devastating conditions may be similar. "Researchers will take several paths to unravel the mechanisms behind cell degradation in the locus coeruleus.

"We are going to look at what has happened in the brains of people with these diseases, including a close examination of post-mortem brain tissue, both from human origin and animal models of Alzheimer's disease, Parkinson's disease, and Down syndrome. direct comparisons in how the brain communicates in people with and without dementia "Dierssen adds.

This project will carry out an intensive examination of the noradrenergic system in these patients; this is a brain chemistry system based on the neurotransmitter noradrenaline, which regulates attention, memory, and arousal. Noradrenergic neurons reside on locus coeruleus, and their activity affects other brain areas.

Besides, researchers will pay particular attention to the information contained in the chromosome 21. Down syndrome is caused by an extra copy of chromosome 21, and it is known that almost all Down syndrome patients develop dementia over the age of 40, which suggests that there are genes on this chromosome that could be implicated in dementia.

Dierssen concludes: "If we can identify common mechanisms of dementia onset, this may lead to the development of therapeutic targets which might slow down or even prevent the onset of dementia in these aforementioned diseases."