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Updated: Aug 25, 2026
Enrichment of Mammalian Tissues and Xenopus Oocytes with Cholesterol
Published on: March 25, 2020
Role of cholesterol in cardiovascular dysfunction
Harjot K Saini1, Amarjit S Arneja, Naranjan S Dhalla
1Institute of Cardiovascular Sciences, St Boniface General Hospital Research Centre, and Department of Physiology and Medicine, University of Manitoba, Winnipeg.
Insights
High cholesterol, or hypercholesterolemia, directly impairs heart function by altering cell membranes and enzyme activity, independent of atherosclerosis. This direct impact on cardiovascular cells contributes to heart dysfunction.
Area of Science:
- Cardiovascular Biology
- Lipid Metabolism
Background:
- Hypercholesterolemia (high cholesterol) is a known risk factor for atherosclerosis and myocardial ischemia.
- The direct impact of cholesterol on cardiac function, separate from atherosclerosis, is not fully understood.
Purpose of the Study:
- To investigate the direct effects of hypercholesterolemia on cardiovascular function.
- To elucidate the mechanisms by which elevated cholesterol impacts cardiac cells and vasculature.
Main Methods:
- Examined the role of cholesterol in biological membrane structure and function.
- Assessed the impact of altered membrane cholesterol on myocardial contractility, excitability, and conduction.
- Investigated the effects of cholesterol on cardiac sarcolemmal enzymes (e.g., Na+-K+ ATPase) and ion transporters (e.g., Na+-Ca2+ exchanger).
- Evaluated cholesterol's influence on endothelial and smooth muscle cells independent of atherosclerotic lesions.
Main Results:
- Elevated cholesterol alters membrane fluidity and function, affecting myocardial cells directly.
- Cardiac enzyme activities (Na+-K+ ATPase, Mg2+ ATPase, Ca2+ pump ATPase) and ion transport (Ca2+-dependent K+ channels, Na+-Ca2+ exchanger) are modified by cholesterol levels.
- Endothelial dysfunction and smooth muscle abnormalities occur due to high cholesterol, even without visible atherosclerosis.
- Oxidative modification of cholesterol contributes indirectly to atherosclerosis and ischemia.
Conclusions:
- Hypercholesterolemia directly causes cardiovascular dysfunction by altering membrane fluidity, enzyme activity, and cation transport in endothelial cells, vascular smooth muscle cells, and cardiomyocytes.
- Atherosclerosis development is linked to cholesterol oxidation products, leading to indirect cardiovascular effects via ischemic heart disease.
Background:
Hypercholesterolemia, which is characterized by high levels of lipoprotein-containing cholesterol in plasma, is generally accepted as a major risk factor for the development of atherosclerosis and subsequent myocardial ischemia. The cardiovascular effects of elevated serum cholesterol are predominantly attributed to atherosclerotic lesions in coronary arteries; however, the role of cholesterol in causing heart dysfunction without the occurrence of atherosclerosis is not fully appreciated.
Observations:
Each type of biological membrane has a specific amount of cholesterol, which is required for proper functioning of the membrane-bound enzymes and cation transporters. High levels of cholesterol have been demonstrated to cause changes in membrane structure and function independent of atherosclerosis. Particularly, alterations in membrane cholesterol content have been shown to affect myocardial contractility, excitability and conduction properties. The activities of cardiac sarcolemmal enzymes such as Na+-K+ ATPase, Mg2+ ATPase and Ca2+ pump ATPase as well as Ca2+-dependent K+ channels and Na+-Ca2+ exchanger are altered as a consequence of changes in the membrane cholesterol content. Furthermore, high levels of cholesterol are known to cause endothelial dysfunction and smooth muscle abnormalities, which occur without visible atherosclerosis lesion development. On the other hand, indirect effects of cholesterol on the cardiovascular system are evident on its oxidative modification and subsequent development of visible atherosclerotic lesions and myocardial ischemia.
Conclusions:
Hypercholesterolemia has been shown to cause cardiovascular dysfunction due to direct action on membrane fluidity, enzyme activities and cation transporters in the endothelial cells, vascular smooth muscle cells and cardiomyocytes. On the other hand, development of atherosclerosis by high levels of cholesterol is associated with the oxidation products of cholesterol and is thus considered to affect the cardiovascular system indirectly as a consequence of ischemic heart disease.
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