Tuesday January 22, 2019

Cholesterol Can Increase Risk of Alzheimer’s Disease, Finds Research

In the case of Alzheimer's disease, the amyloid-beta molecules stick to the lipid cell membranes that contain cholesterol.

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In Alzheimer's disease, patients start losing memory, Pixabay

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.

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.
Junk Food is highly rich in Cholesterol, pixabay

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.

Also Read: Small Head Blows Can Also Increase Risk of Dementia 

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)

Next Story

Poor Sleep May Signal The Risk of Alzheimer’s in Elderly

For the study, the team studied 119 people aged 60 or older among which almost 80 per cent were cognitively normal and the remainder were very mildly impaired

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alzheimer's, cholesterol
Poor sleep can predict Alzheimer's Risk in elderly. Pixabay

Poor sleep quality may signal the risk of Alzheimer’s disease in older adults, a study suggests.

People with Alzheimer’s tend to wake up tired and their nights become even less refreshing as memory loss and other symptoms worsen.

However, the reason was not fully understood.

The study, led by the Washington University in St. Louis found that older adults who sleep poorly or have less slow-wave sleep — deep sleep needed to consolidate memories and wake up feeling refreshed — have higher levels of tau — a toxic brain protein.

Tau has also been linked to brain damage and cognitive decline.

“Measuring how people sleep may be a non-invasive way to screen for Alzheimer’s disease before or just as people begin to develop problems with memory and thinking,” said lead author Brendan Lucey, Assistant Professor from the varsity.

"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.
In Alzheimer’s disease, patients start losing memory, Pixabay

Moreover, the findings, published in the journal Science Translational Medicine, showed that it was not the total amount of sleep that was linked to tau, but the slow-wave sleep, which reflects quality of sleep.

The people with increased tau pathology were actually sleeping more at night and napping more in the day, but they weren’t getting as good quality sleep.

“What’s interesting is that we saw this inverse relationship between decreased slow-wave sleep and more tau protein in people who were either cognitively normal or very mildly impaired, meaning that reduced slow-wave activity may be a marker for the transition between normal and impaired,” Lucey added.

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For the study, the team studied 119 people aged 60 or older among which almost 80 per cent were cognitively normal and the remainder were very mildly impaired.

Up to two decades before Alzheimer’s symptoms of memory loss and confusion appear, amyloid beta protein begins to collect into plaques in the brain. Tangles of tau appear later, followed by decline of key brain areas. Only then do people start showing unmistakable signs of cognitive decline.

The challenge is finding people on track to develop Alzheimer’s before such brain changes undermine their ability to think clearly. For that, sleep may be a handy marker, the researchers said. (IANS)