People with raised cholesterol don’t just have an increased risk of heart disease – they may be more likely to develop dementia.
Researchers have found that high cholesterol levels are significantly related to brain plaques associated with Alzheimer’s disease.
And now, American scientists say they have found the reason why high cholesterol can damage the brain and blood vessels.
Using insights gained from studying two much rarer disorders, Down Syndrome and Niemann Pick-C disease, researchers found that cholesterol wreaks havoc on the orderly process of cell division.
That’s because cholesterol, particularly in the ‘bad’ LDL form, causes cells in both humans and mice to divide incorrectly and distribute their already-duplicated chromosomes unequally to the next generation.
The result is an accumulation of defective cells with the wrong number of chromosomes – and therefore the wrong number of genes.
Instead of the correct two copies of each chromosome, and therefore two copies of each gene, some cells acquired three copies and some only on, the researchers at the Linda Crnic Institute for Down Syndrome and University of Colorado found.
They also found that cells carrying three copies of the chromosome were associated with the damaging protein amyloid, which occurs between nerve cells – and people with Alzheimer’s have amyloid plaques in their brains.
The study is published in the online journal PLOS ONE.
Previous research has found that people with high cholesterol levels, defined by a reading of more than 5.8 mmol/L, had significantly more brain plaques when compared to those with normal or lower cholesterol levels.
A total of 86 percent of people with high cholesterol had brain plaques, compared with only 62 percent of people with low cholesterol levels, the researchers from Japan’s Kyushu University found.
Using autopsies, they looked for plaques and tangles in the brain, both known to be trademark signs of Alzheimer’s disease.
Plaques are an accumulation of a form of the protein amyloid, which occurs between nerve cells. Tangles are an accumulation of a different protein, called tau, which occurs inside nerve cells.
While the study found no link between high cholesterol and the tangles that develop in the brain with Alzheimer’s disease, there was a definite link with plaques.