Abstract Background Diabetes mellitus (DM) significantly elevates the risk of cardiovascular disease beyond traditional risk factors. High-density lipoprotein (HDL) generally supports atheroprotective roles through its lipid and protein constituents. However, emerging evidence suggests that diabetes may alter HDL’s composition and function. It remains unclear whether qualitative changes in HDL, even when HDL-cholesterol (HDL-C) levels are normal, contribute to subclinical atherosclerosis. Purpose This study aims to investigate the relationship between structural and compositional abnormalities in HDL particles and the presence of subclinical atherosclerosis and disease progression in individuals with type 2 diabetes mellitus (T2DM) who maintain normal HDL-C levels. Methods We conducted a cross-sectional study in T2DM patients (n=75) assessing subclinical atherosclerosis by computed tomography. A control group (n=29) without subclinical atherosclerosis was included. HDL particles were isolated from fasting plasma, and comprehensive lipidomic and proteomic profiles were obtained through high-resolution LC–MS/MS. HDL characterization, including particle size, composition, and subclasses, was performed using 1H-NMR spectroscopy. Results T2DM patients exhibiting subclinical atherosclerosis showed marked alterations in HDL proteome and lipidome. Specifically, ApoE and PON3 levels were lower, and PCSK9 content was higher in T2DM patients vs controls (p0.008). These changes correlated with systemic plasma protein concentrations, facilitating discrimination of disease severity by imaging (p0.007). HDL from T2DM patients with subclinical atherosclerosis demonstrated extensive lipid remodelling, with distinct differences from controls and significant shifts across lipid classes. HDL particles showed a substantial decrease in essential lipids such as cholesterol esters, phosphatidylcholines (key for membrane fluidity and cholesterol efflux), and plasmalogens (involved in HDL-related antioxidative properties) and increased content of triglycerides and phosphatidylethanolamine (PE) enriched in monounsaturated fatty acids. Of note, PE(34:1) strongly associated with the presence of disease (AUC=0.92). 1H-NMR analyses indicated a shift toward smaller, pro-atherogenic HDL particles and a lower concentration of medium- and large- HDLs. Finally, ROC curves demonstrated that medium and large HDL particle counts were superior predictors of coronary obstruction and calcium score compared to HDL-C concentration alone. Conclusions T2DM patients with HDL-C levels within the normal range exhibit HDL-particles with structural and compositional alterations that enable the discrimination of subclinical atherosclerosis severity. Specifically, changes in PON3, PCSK9, and ApoE levels, as well as HDL particle size, may become potential biomarkers of early cardiovascular risk in T2DM patients.
Martinez et al. (Fri,) studied this question.