Not all “good” cholesterol is healthy

The work shows that people with large HDL particles are at an increased risk of myocardial infarction, while only small HDL particles are actually associated with a decreased risk.

HDL cholesterol (high density lipoprotein cholesterol), or good cholesterol, is linked to a reduced risk of cardiovascular disease because it carries cholesterol deposited in the arteries to the liver to be cleared. This is in contrast to what is known as bad cholesterol, LDL (Low Density Lipoprotein Cholesterol), which causes cholesterol to build up in the arteries and increases cardiovascular risk.

Although drugs that lower bad cholesterol lower cardiovascular risk, those that increase good cholesterol have not been shown to be effective in reducing the risk of heart disease. This paradox has challenged the relationship between good cholesterol and cardiovascular risk, and researchers are now studying the properties of these HDL, or good cholesterol, particles.

A study by the Medical Research Institute of Hospital del Mar (IMIM) published in the journal Metabolism, Clinical and Experimental has now shown that not all good cholesterol is healthy. Researchers from CIBER for Cardiovascular Diseases (CIBERCV), CIBER for Obesity and Nutrition (CIBEROBN) and CIBER for Epidemiology and Public Health (CIBERESP), as well as other staff from the Hospital Clínic-IDIBAPS, IDIBELL, the Hospital de la Santa Das Research institute Creu i Sant Pau and the Clínico Universitario hospital in Zaragoza also took part in this study.

In the work, the researchers analyzed genetic properties that determine the size of good cholesterol particles, then examined their relationship to the risk of myocardial infarction. The conclusion is that genetic traits associated with producing large good cholesterol particles are directly linked to a higher risk of heart attack, while traits linked to small good cholesterol particles are linked to a lower risk of heart attack. “There is a positive causal relationship between the size of the HDL cholesterol particles and the risk of a heart attack. Although we need to increase the level of good cholesterol in the blood, the particles always have to be small,” explains the study’s lead researcher. Dr. Robert Elosua, researcher at Hospital del Mar-IMIM, CIBERCV, and the University of Vic-Central University of Catalonia (UVic-UCC).

The good cholesterol particles transfer cholesterol to the liver more effectively so that it can be eliminated. “If we have to do anything about HDL, we have to increase the number of small particles that do the job of properly clearing cholesterol that actually carry it to the liver for removal rather than allowing it to build up in the arteries and prevent cardiovascular disease. Causing illness, “says Dr. Álvaro Hernáez, an IDIBAPS and CIBEROBN researcher.

There are currently no drugs that can increase good cholesterol and reduce the risk of cardiovascular disease. “This study highlights new and potential therapeutic targets in cardiovascular disease, including several genes that are related to the qualitative aspects of HDL particles and may contribute to cardiovascular prevention,” concludes Dr. Albert Prats, a researcher in the Epidemiology and Cardiovascular Genetics Research Group at Hospital del Mar-IMIM and lead author of the study.

Reference: “High density lipoprotein properties and coronary artery disease: a Mendelian randomization study” by Albert Prats-Uribe, Sergi Sayols-Baixeras, Alba Fernández-Sanlés, Isaac Subirana, Robert Carreras-Torres, Gemma Vilahur, Fernando Civeira and Jaume Marrugat, Montserrat Fitó , Álvaro Hernáez and Roberto Elosua, September 3, 2020, Metabolism, Clinical and Experimental.
DOI: 10.1016 / j.metabol.2020.154351

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