Scientists in the United Kingdom have discovered how a key chemical alters brain cells in a common type of dementia. In addition, the researchers discovered that the insult leads to a chain effect throughout the brain.
The researchers found that the brain tissue of people with dementia with Lewy bodies (DLB) contained a particular form of protein in the vital parts of the neurons that connect the cells. Their findings suggest that this destructive protein can jump from one cell to another through these connections.
DLB is the second most common type of progressive dementia after the dementia of Alzheimer's disease and attacks the brain regions involved in thinking, memory and movement (motor control). Scientists say the new findings shed light on the causes of DLB and will help speed the search for treatment as there is currently no cure for DLB.
The study, co-directed by the University of Edinburgh, focused on synapses, the shared connection points between brain cells that allow chemical and electrical signals to flow between cells. These signals are vital to transmit nervous messages and form memories, and are key to brain health.
The researchers showed that synapses in five people who had died with DLB contained groups of the harmful protein, known as alpha-synuclein, that could contribute to the symptoms of dementia. The toxic alpha-synuclein was detected on both sides of the synapses, suggesting that it can jump between cells through these connections. This discovery reveals how the damage could spread through the brain.
No similar findings were observed in the brain tissue of people who had died with Alzheimer's disease or without dementia.
New imaging technology helped the discovery as scientists were able to see detailed images of more than one million unique synapses. Individual synapses are about 5,000 times smaller than the thickness of a sheet of paper. The researchers write that this study was the first to use sophisticated technology for the study of DLB.
Although alpha-synuclein groups had previously been identified in DLB, their effects on synapses were unknown due to the difficulties in studying them due to their small size.
"DLB is a devastating condition and our findings suggest that, at least in part, it is due to damage to synapses." These findings should strengthen the search for therapies aimed at reducing synaptic damage and open the possibility of directing the spread of alpha-synuclein through the brain, which could stop the progression of the disease, "said study leader Professor Tara Spiers-Jones.  Dr. Rosa Sancho, director of research at Alzheimer & # 39; s Research UK, said: "This interesting research using cutting-edge technology sheds new light on the progression of DLB in the brain." The results provide convincing, measurable and visual evidence that the toxic alpha-synuclein is altering the synapses that could contribute to the devastating symptoms of the disease.
"We are extremely pleased that our funds have helped produce these important results that demonstrate possible avenues for much needed new treatments for people who live with DLB. "
Source: University of Edinburgh
Nauert PhD, R. (2017) How a type of dementia is spread through the brain Psych Central .
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