High blood cholesterol increases risk of Alzheimer’s and heart disease: Study
Researchers at the Linda Crnic Institute for Down Syndrome and the University of Colorado School of Medicine have found that a single mechanism may underlie the damaging effect of cholesterol on the brain and on blood vessels. High levels of blood cholesterol increase the risk of both Alzheimer’s disease and heart disease, but it has been unclear exactly how cholesterol damages the brain to promote Alzheimer’s disease and blood vessels to promote atherosclerosis.
Using insights gained from studying two much rarer disorders, Down Syndrome and Niemann Pick-C disease, researchers at the Linda Crnic Institute for Down Syndrome and the Department of Neurology of the University of Colorado School of Medicine found that cholesterol wreaks havoc on the orderly process of cell division, leading to defective daughter cells throughout the body.
In the new study published this week in the on-line journal PLOS ONE, Antoneta Granic, PhD, and Huntington Potter, PhD, show that cholesterol, particularly in the LDL form, called ‘bad cholesterol’, 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 daughter cells with the wrong number of chromosomes and therefore the wrong number of genes. Instead of the correct two copies of each chromosome, and thus two copies of each gene, some cells acquired three copies and some only one.
The new research also found trisomy 21 neurons in the brains of children with what, until now, was thought to be an unrelated neurodegenerative disease (Niemann Pick type C), caused by a mutation affecting cholesterol physiology. This result suggests that neurodegeneration itself might be linked to chromosome missegregation. Such a model is supported by the finding of Thomas Arendt, MD, and colleagues at the University of Leipzig that 90% of the neuronal cell death observed at autopsy in Alzheimer patients is due to the creation and selective loss of neurons with the wrong number of chromosomes.