Tuesday March 19, 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.

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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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Eye Test May Help in Early Detection of Alzheimer’s Disease

Conversely, in the eyes of 39 people with Alzheimer's disease, that web was less dense and even sparse in places

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

A future non-invasive eye test may allow early detection of Alzheimer’s disease before memory loss kicks in, say a team led by an Indian-origin researcher.

Retina being an extension of the brain, the optical coherence tomography angiography (OCTA) will check patients’ vision as well as brain health, said the study published in the journal Ophthalmology Retina.

The researchers said that loss of blood vessels in retina would reflect changes in the brain, be it for both healthy people or Alzheimer’s patients.

“We know that there are changes that occur in the brain in the small blood vessels in people with Alzheimer’s disease, and because the retina is an extension of the brain, we wanted to investigate whether these changes could be detected,” said lead author Dilraj S. Grewal, ophthalmologist at Duke University.

Using the OCTA that uses light waves that reveal blood flow in every layer of the retina, the researches checked more than 200 people.

A lady suffering from Alzheimer’s. Flickr

They found that in people with healthy brains, microscopic blood vessels form a dense web at the back of the eye inside the retina — as was seen in 133 participants in a control group.

Conversely, in the eyes of 39 people with Alzheimer’s disease, that web was less dense and even sparse in places.

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The OCTA machines, relatively a new noninvasive technology, measures blood vessels that cannot be seen during a regular eye examination.

“It’s possible that these changes in blood vessel density in the retina could mirror what’s going on in the tiny blood vessels in the brain, perhaps before we are able to detect any changes in cognition,” added Sharon Fekrat, ophthalmologist at the Duke University in the US. (IANS)