New Insight On Synapse Loss In Dementia

Scientists in Australia have discovered how synapse connections are destroyed in early stage Alzheimer's disease. 

There are many remaining mysteries about Alzheimer's disease, and its causes are still hazy. By unraveling more and more about exactly how this disease unfolds, there is hope we'll produce better targets and therefore better medicine to beat it back. 

"One of the first signs of Alzheimer's disease is the loss of synapses - the structures that connect neurons in the brain. Synapses are required for all brain functions, and particularly for learning and forming memories. In Alzheimer's disease, this loss of synapses occurs very early on, when people still only have mild cognitive impairment, and long before the nerve cells themselves die"

Honing in on the synapse

By looking closer at these degrading synapses, the researchers zoomed in on a protein called neural cell adhesion molecule 2, or NCAM2. This is a key molecule that helps attach synapse membranes and stabilises contact between neighbours. 

By looking at post-mortem brain tissue, they discovered levels of this NCAM2 were lower in the hippocampal region - in which new memories are consolidated and neurogenesis occurs. They also found that NCAM2 was broken down by beta-amyloid, a plaque forming molecule associated with Alzheimer's disease.

"Our research shows the loss of synapses is linked to the loss of NCAM2 as a result of the toxic effects of beta-amyloid. It opens up a new avenue for research on possible treatments that can prevent the destruction of NCAM2 in the brain"

Read more at Eurekalert