April 16, 2013
Understanding Why Cholesterol Is Linked To Alzheimer’s And Heart Disease
Michael Harper for redOrbit.com — Your Universe Online
Multiple studies have concluded high amounts of cholesterol can be damaging to your heart and can, in turn, lead to Alzheimer´s disease or stroke. Though this single fact has been well documented, the exact reason why high cholesterol affects the brain has been largely unclear for many years.
Researchers from the Linda Crnic Institute for Down Syndrome and the University of Colorado School of Medicine have studied this link and have discovered a single mechanism which may explain why high cholesterol damages blood vessels and the brain.
The researchers from these two institutions called upon previous studies on Down Syndrome and Neimann Pick-C disease, a condition which prevents the patient from metabolizing cholesterol correctly within the cell. This causes cholesterol to accumulate in the liver and spleen while high amounts of lipids gather in the brain.
After looking at this prior research, the team discovered cholesterol has a way of terrorizing the cell division process which then leads to defective daughter cells throughout the body. This study has now been published in the online journal PLoS ONE.
Antoneta Granic, PhD, and Huntington Potter, PhD, study co-authors, say they´ve discovered “bad cholesterol" (LDL) causes cells to divide incorrectly. This incorrect division of the daughter cells is then passed down from generation to generation. The problem continues as the cells continue to split and grow, resulting in the wrong number of chromosomes and the wrong number of genes. For example, as the accumulation of defective cells continues, some cells will end up with three copies of the correct chromosome and gene while others are left with only one correct copy. The cells are therefore unbalanced, and this effect has been observed in the cells of both humans and mice.
These unbalanced cells can lead to further problems, such as Alzheimer´s disease. Doctors Granic and Potter discovered the same kind of genetic unbalance in their study cells that are often found in patients with Alzheimer´s disease, leading them to believe this defective cell division is the link between the two.
The two doctors also noticed a similar genetic unbalance in patients with Down Syndrome.
Previous research has shown all people with Down Syndrome have “trisomy 21” in their cells from the very moment they are conceived. The child will then develop Down Syndrome as they grow and many come to develop the dementia which accompanies Alzheimer´s by age 50.
Doctors Granic and Potter have discovered in earlier studies that as many as 10 percent of Down Syndrome patients have the same sort of unbalanced genetics in their cells with three copies of the 21 chromosome instead of two. This led the two doctors to conclude Alzheimer´s is, in many ways, a form of Down Syndrome. The same mutant genes which cause an inherited case of Alzheimer´s have also been found to split in much the same way as the cells affected by high amounts of bad cholesterol.
This new research also found the same trisomy 21 cells in the brains of children who had been previously diagnosed with Neimann Pick-C disease. The doctors say this could mean these cells might react differently to high levels of bad cholesterol.
With their new discovery, the two researchers say future doctors and researchers will be able to approach diseases like Alzheimer´s in a different way. Any disease which involves a defect in cell division could also be affected by this research. As a start, the doctors discovered they could prevent cholesterol from splitting cells defectively by treating them with ethanol first. After being treated in this way, even cells which came in contact with bad cholesterol split with the correct number of chromosomes.