Alzheimer’s disease is the most common form of dementia, the World Health Organization has revealed that it affects more than 55 million people.
BMC/BioMed Central said that for more than 40 years, researchers have widely believed in the amyloid cascade hypothesis; that the symptoms of Alzheimer’s disease are due to an accumulation of insoluble beta-amyloid plaques in the brain.
Beta-amyloid plaques are common in people with Alzheimer’s disease, therefore they have generally been thought to be responsible for the deterioration in cognitive function that is characteristic of the disease.
However, many people accumulate amyloid plaques in the brain as they age, but only some of them develop dementia.
A new study has suggested that the symptoms of dementia do not result from insoluble plaques but from a lack of soluble beta-amyloid protein.
The University of Cincinnati, OH study, which appeared in the Journal of Alzheimer’s Disease, suggests an alternative theory – that Alzheimer’s symptoms are not caused by an increase in insoluble amyloid plaques, but by a decrease in beta -soluble amyloid which is essential for cognitive function.
According to this hypothesis, soluble beta-amyloid protein deposits and forms insoluble amyloid plaques, which damage neurons and synapses.
This impairs the normal transmission of nerve impulses, leading to symptoms such as memory loss, language problems and unpredictable behavior.
Sian Gregory, head of research information at the Alzheimer Society, said: “This study looked at a specific type of inherited Alzheimer’s disease that accounts for less than 1% of cases. This suggests that in people who have inherited Alzheimer’s disease linked to specific genes, amyloid plaques may play a different role in memory decline than previously thought. The study highlights that amyloid is still an important feature of Alzheimer’s disease and its diagnosis.
Building on seminal research funded by the Alzheimer Society by pioneering researcher Sir John Hardy in the 1980s, we now know that amyloid is just one of many facets of the development of Alzheimer’s disease, which also includes key players such as tau accumulation and inflammation.
Understanding what goes wrong in the brain to cause diseases that lead to dementia is crucial to developing the targeted treatments that people with dementia desperately need. This research highlights the importance of continued investment in dementia research to deepen our understanding of how these diseases develop, which will revolutionize diagnosis and the search for new treatments.