Very-Low-Density Lipoproteins Quantity but Not Composition Is Altered in Normotriglyceridemic Subjects with Elevated Lipoprotein (a) Level

Cardiovascular disease (CVD) is influenced by disturbances in lipoprotein composition and metabolism, including triglyceride-rich lipoproteins (TRLs) and elevated lipoprotein (a) (Lp(a)). While interactions between Lp(a) and very-low-density lipoproteins (VLDL) have been studied in hypertriglyceridemic and CVD populations, data in normotriglyceridemic individuals without CV events are limited. Seventy normotriglyceridemic adults with triglycerides < 150 mg/dL and no CV events were enrolled and divided into two groups based on Lp(a) concentration: <30 mg/dL and ≥30 mg/dL. VLDL was isolated by ultracentrifugation, and concentrations of Lp(a), lipids (triglycerides, cholesterol), and apolipoproteins (apo B, apo C-II, apo C-III, apo E) were measured in serum and VLDL. Serum lipid and apolipoprotein concentrations did not differ between the groups. Individuals with Lp(a) ≥ 30 mg/dL had significantly higher VLDL concentrations of triglycerides (+71%), cholesterol (+54%), apo B (+28%), apo C-II (+36%), and apo C-III (+33%). Ratios of lipids and apolipoproteins to apo B indicated unchanged VLDL particle composition, suggesting that differences reflected increased particle number rather than altered composition. In normotriglyceridemic subjects with Lp(a) ≥ 30 mg/dL, VLDL particles are more abundant but compositionally unchanged. Redistribution of lipids and apolipoproteins toward VLDL may contribute to VLDL residual cardiovascular risk, underscoring the need for further studies on VLDL-Lp(a) interactions.