Changing views on the causes of atherosclerosis
Sep 10, 2024Summary: Atherosclerosis causes thickening of arteries and plaque formation. It considerably increases the risk of cardiovascular events like heart attack and stroke. The traditional model shows that atherosclerosis develops due to adiposity, smoking, high blood pressure, causing accumulation of cholesterol. Additionally, the role of inflammation is well known. Early understandings show that high LDL cholesterol is associated with a greater risk of atherosclerosis, and on the contrary, high HDL cholesterol has a lower risk. But, now, the new studies show that it is partially true. Thus, it appears that high HDL may not be as beneficial as thought earlier.
Similarly, it seems that triglyceride-rich lipoproteins play a more significant role than LDL cholesterol in disease development. Further, other factors contribute to the continued rise of atherocelrosis like environmental stressors, changes in microbiome, sleep disorders, etc. Additionally, researchers are exploring the role of bone marrow and stem cells in disease development.
Atherosclerosis is a complex disorder. It causes the formation of plaques in the arterial walls. These plaques may rupture, causing a heart attack, stroke, and peripheral arterial disease. Researchers have long known the role of thickening of arteries caused by high consumption of fats and a sedentary lifestyle.
Doctors know that preventing atherosclerosis is one of the keys to preventing cardiovascular diseases. Studies show its high relationship with conditions like smoking, high blood pressure, adiposity, and diabetes.
Researchers also realize that apart from high cholesterol, inflammation and high activity of reactive oxygen species have a role in vascular damage1,2.
These previous understandings of atherosclerosis helped identify the ominous role of LDL- cholesterol. Further, it appears that high HDL-cholesterol may have a protective role, as it helps remove cholesterol from the circulation.
These understandings help design new dietary and other lifestyle interventions. Moreover, these interventions did provide excellent results. Thus, most western Europe and the US have seen a consistent decline in cardiovascular ailments since the mid-20th century3.
However, these measures had limitations. It now seems that atherosclerosis is rising in some parts of the world. It is despite a low-fat diet and reduction in smoking rates. Moreover, atherosclerosis is becoming more common in young individuals and females. All this led the researcher to reconsider their early findings. It is clear that they are still missing something.
Figure 1 development of atherosclerosis4
New views on atherosclerosis
Researchers think that to reduce cardiovascular mortality further, they need to shift focus from LDL cholesterol, smoking, and blood pressure. Additionally, new studies show that HDL may not be as protective as supposed earlier.
There could be many reasons for these new findings. The human lifestyle has changed considerably since the mid of the 20th century. Additionally, there is also a need to identify less prominent causes of atherosclerosis. Further, improved technology may help identify some other protective mechanisms.
Thus, it is not to say that factors identified earlier are irrelevant. Instead, the new findings only mean that there are other lesser-known risk factors and protective mechanisms.
Thus, it appears that triglyceride-rich lipoproteins may be playing an important role in the disease progress along with LDL cholesterol4.
Further, there is a need to focus the attention on factors not considered earlier, like changes in sleep pattern, environmental stress, microbiome, the role of prolonged physical inactivity.
New studies are also focusing on the role of bone marrow in atherosclerosis. It is no secret that the inflammatory pathway plays a vital role in its development. It appears that many inflammatory responses change with aging. Especially mutations in stem cells may play a significant role in the disease development4.
New studies try to explore the pathogenesis of conditions in various ways. It tries to look beyond the traditional concept that fatty plaque and inflammation are central to atherosclerosis.
Although these are still some of the early findings and concepts, researchers think that understanding them better would help further reduce the risk of atherosclerosis. Thus, we might see the introduction of very different kinds of therapeutic approaches to reducing the risk of atherosclerosis.
References
- Kattoor AJ, Pothineni NVK, Palagiri D, Mehta JL. Oxidative Stress in Atherosclerosis. Curr Atheroscler Rep. 2017;19(11):42. doi:10.1007/s11883-017-0678-6
- Libby P. Inflammation in Atherosclerosis. Arteriosclerosis, Thrombosis, and Vascular Biology. 2012;32(9):2045-2051. doi:10.1161/ATVBAHA.108.179705
- Herrington W, Lacey B, Sherliker P, Armitage J, Lewington S. Epidemiology of Atherosclerosis and the Potential to Reduce the Global Burden of Atherothrombotic Disease. Circulation Research. 2016;118(4):535-546. doi:10.1161/CIRCRESAHA.115.307611
- Libby P. The changing landscape of atherosclerosis. Nature. 2021;592(7855):524-533. doi:10.1038/s41586-021-03392-8
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