London May 8 (IANS) Cholesterol -- a molecule normally linked with cardiovascular diseases -- may also play an important role in the onset and progression of Alzheimer s disease researchers have found.
The findings published in the journal Nature Chemistry suggests that in the brain cholesterol acts as a catalyst which triggers the formation of the toxic clusters of the amyloid-beta protein which is a central player in the development of Alzheimer s disease.
The researchers found that cholesterol which is one of the main components of cell walls in neurons can trigger amyloid-beta molecules to aggregate and their aggregation eventually leads to the formation of amyloid plaques in a toxic chain reaction that leads to the death of brain cells.
"The levels of amyloid-beta normally found in the brain are about a thousand times lower than we require to observe it aggregating in the laboratory - so what happens in the brain to make it aggregate?" said lead author Michele Vendruscolo Professor at Centre for Misfolding Diseases in the University of Cambridge.
For the study using a kinetic approach the researchers found in vitro studies that the presence of cholesterol in cell membranes can act as a trigger for the aggregation of amyloid-beta.
Since amyloid-beta is normally present in such small quantities in the brain the molecules don t normally find each other and stick together. Amyloid-beta does attach itself to lipid molecules however which are sticky and insoluble the researcher said.
In the case of Alzheimer s disease the amyloid-beta molecules stick to the lipid cell membranes that contain cholesterol.
Once stuck close together on these cell membranes the amyloid-beta molecules have a greater chance to come into contact with each other and start to aggregate - in fact the researchers found that cholesterol speeds up the aggregation of amyloid-beta by a factor of 20.
"The question for us now is not how to eliminate cholesterol from the brain but about how to control cholesterol s role in Alzheimer s disease through the regulation of its interaction with amyloid-beta " Vendruscolo said.
"We re not saying that cholesterol is the only trigger for the aggregation process but it s certainly one of them " Vendruscolo added.
--IANS
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