Lipoprotein-associated phospholipase A2 distribution among lipoproteins differs in type 1 diabetes

Abstract

Background: LpPLA2 mass and activity have been variably related to cardiovascular disease risk, and the distribution of LpPLA2 in patients with type 1 diabetes (T1D), wherein cardiovascular disease risk is high despite normal or higher levels of high-density lipoprotein (HDL) cholesterol, is unknown.

Objective: To determine whether there are differences in the distribution of LpPLA2 mass and activity across lipoproteins and their association with coronary artery calcium (CAC) in patients with T1D.

Methods: Men with T1D (n = 19) not on statins, with and without CAC progression, and men without diabetes matched for HDL cholesterol (n = 25) had lipoproteins separated by fast protein liquid chromatography.

Results: Both LpPLA2 mass and activity were found within low-density lipoprotein (LDL) and HDL pools with more LpPLA2 mass being associated with HDL (54% vs 44%; P-value <.001) and more LpPLA2 activity being associated with LDL (56% vs 40%; P value = .02). In T1D, more LpPLA2 activity was associated with large- or less-dense LDL compared to those without diabetes. However, no difference in LpPLA2 activity or mass between lipoprotein subfractions was observed between all groups, and there was no relationship between LpPLA2 activity or mass and its distribution and CAC score progression in healthy or T1D men.

Conclusion: LpPLA2 is found in both LDL and HDL and is distributed differently in men with T1D without any relationship to CAC score progression.

Keywords: Coronary artery calcium progression; HDL; LDL; Lipoproteins; VLDL.