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Close correlation between high-density lipoprotein and triglycerides in normotriglyceridaemia
J Johansson1, G Walldius, L A Carlson
1King Gustaf V Research Institute, Karolinska Institute, Stockholm, Sweden.
Insights
High-density lipoprotein (HDL) particle size is linked to lipid levels. Smaller HDL particles (HDL3b) correlated with higher triglycerides, while larger HDL particles (HDL2b) were associated with lower triglycerides in men.
Area of Science:
- Lipid metabolism
- Cardiovascular research
- Clinical biochemistry
Background:
- High-density lipoprotein (HDL) plays a crucial role in reverse cholesterol transport.
- HDL exists in various particle size subclasses, which may have differential functional implications.
- Understanding the relationship between HDL subclasses and lipoprotein lipid levels is important for cardiovascular risk assessment.
Purpose of the Study:
- To investigate the association between high-density-lipoprotein (HDL) particle size subclasses and the concentrations of major lipoprotein lipids.
- To determine if these associations differ in individuals with and without a history of cardiovascular events.
Main Methods:
- Polyacrylamide gradient gel electrophoresis (GGE) was used to separate HDL into five size subclasses (HDL2b, HDL2a, HDL3a, HDL3b, HDL3c).
- Cholesterol and triglyceride levels in very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and HDL were measured in 74 men.
- Correlations between HDL subclasses and lipoprotein lipids were analyzed, with stratification based on VLDL triglyceride levels and cardiovascular history.
Main Results:
- VLDL triglycerides showed a negative correlation with HDL2b and a positive correlation with HDL3b concentrations in subjects with normotriglyceridaemia.
- Patients with a history of myocardial infarction or angina pectoris had significantly lower HDL2b levels compared to asymptomatic hyperlipidaemic subjects.
- These differences in HDL2b levels were observed despite similar overall cholesterol and triglyceride levels across VLDL, LDL, and HDL fractions.
Conclusions:
- HDL particle size subclasses are significantly associated with lipoprotein lipid profiles, particularly in normotriglyceridaemic individuals.
- Reduced levels of larger HDL particles (HDL2b) may be a marker for increased cardiovascular risk.
- Further research is warranted to elucidate the functional significance of HDL subclasses in cardiovascular disease pathogenesis.
Abstract:
The relationship between high-density-lipoprotein (HDL) particle size subclasses and the levels of the major lipoprotein lipids was studied in 74 men consecutively referred to the lipid clinic. HDL (density 1.070-1.21 kg l-1) was separated by polyacrylamide gradient gel electrophoresis (GGE) into five size-defined subclasses, in order of decreasing size as follows: HDL2b, HDL2a, HDL3a, HDL3b and HDL3c. Cholesterol and triglyceride concentrations in very-low-density (VLDL), low-density (LDL) and high-density (HDL) lipoproteins were determined. The level of VLDL triglycerides was negatively correlated with HDL2b (r = -0.66, P less than 0.0001), and positively correlated with HDL3b concentrations (r = 0.65, P less than 0.0001). Both correlations were restricted to subjects with VLDL triglyceride concentrations of less than 1.80 mmol l-1, i.e. those with normotriglyceridaemia. Patients with a history of myocardial infarction and/or angina pectoris (n = 18) had significantly lower HDL2b levels than subjects with asymptomatic hyperlipidaemia (n = 50), i.e. 0.16 vs. 0.22 mg protein ml-1 (P less than 0.05), despite essentially similar cholesterol and triglyceride levels in the VLDL, LDL and HDL fractions, including HDL2 and HDL3 cholesterol.