Atherosclerosis involves the hardening and narrowing of the vessels that carry blood to and from the heart caused by the build-up of abnormal plaques (fat, cholesterol, calcium, and other substances circulating in the blood). It is one of the major causes of heart and circulatory disease and is considered to be a disease of the elderly, meaning that most screening, prevention, and intervention programs focus on those with high cholesterol levels, generally after the age of 50.
However, a new study published in Nature led by the University of Cambridge suggests that high cholesterol levels at a younger age, particularly fluctuating levels, can be even more damaging than high cholesterol levels that only begin in later life. Additionally, the study suggests that those taking lipid-lowering drugs such as statins to lower their cholesterol levels should remain on them, even if their levels have decreased, as stopping could increase their risk of atherosclerosis. The findings highlight the need to keep cholesterol levels low even when we are young.
A different approach
To study the mechanisms, scientists often use animal modes of atherosclerosis. Normally the animals were fed a high-fat diet (HFD) for several weeks as adults to examine how this leads to the build-up of the plaque characteristic of the condition. In this study, Professor Ziad Mallat and colleagues at the Victor Phillip Dahdaleh Heart and Lung Research Institute at the University of Cambridge, used a different approach, giving mice the same amount of high-fat food but it was spread over their lifetime to see if it changed their atherosclerosis risk.
“When I asked my group and a number of people who are experts in atherosclerosis, no one could tell me what the result would be,” said Professor Mallat, a British Heart Foundation (BHF) Professor of Cardiovascular Medicine. “Some people thought it would make no difference, others thought it would change the risk. In fact, what we found was that an intermittent high-fat diet starting while the mice were still young — one week on, a few weeks off, another week on, and so on — was the worst option in terms of atherosclerosis risk.”
Confirming their findings
Next, the team utilized data from the Cardiovascular Risk in Young Finns Study, one of the largest follow-up studies into cardiovascular risk from childhood to adulthood. Participants recruited in the 1980s returned for follow-up over the subsequent decades, and more than 2,000 of them had received ultrasound scans of their carotid arteries when they were aged around 30 years and again at around 50 years. The data analysis revealed that those who had been exposed to high cholesterol levels as children tended to have the biggest build of plaques, confirming the findings in mice.
“What this means is that we shouldn’t leave it until later in life before we start to look at our cholesterol levels,” Professor Mallat said. “Atherosclerosis can potentially be prevented by lowering cholesterol levels, but we clearly need to start thinking about this much earlier on in life than we previously thought.”
Fluctuating cholesterol levels
Fluctuating levels of cholesterol were found to cause the most damage, the researchers believe that this may explain why some people who are on statins but do not take them regularly remain at an increased risk of heart attack.
Why fluctuating levels may be so damaging could come down to the effect that cholesterol has on resident arterial macrophage immune cells. These cells can be found in your arteries, helping to clear damaged cells and lipids, which include cholesterol, and stopping the build-up of plaques.
Examining macrophages in mouse models revealed that high cholesterol levels, in particular, fluctuating cholesterol levels, changed them physically and altered the activity of their genes. The cells were found to be no longer protective, they had become detrimental, accelerating atherosclerosis.
As with anything you read on the internet, this article should not be construed as medical advice; please talk to your doctor or primary care provider before changing your wellness routine. WHN does not agree or disagree with any of the materials posted. This article is not intended to provide a medical diagnosis, recommendation, treatment, or endorsement. Additionally, it is not intended to malign any religion, ethnic group, club, organization, company, individual, or anyone or anything. These statements have not been evaluated by the Food and Drug Administration.
Content may be edited for style and length.
References/Sources/Materials provided by:
This article was created using a Created Commons International License
https://creativecommons.org/licenses/by-nc-sa/4.0
