March 23, 2012 — Researchers using the VAP (vertical auto profile) Cholesterol Test to isolate lipid subfractions and assess a new anti-flushing agent have reported significant baseline reductions in the cholesterol content of lipoproteins across the entire very low density lipoprotein (VLDL) to low density lipoprotein (LDL) density range in dyslipidemic patients.
In the study “Effects of coadministered extended-release niacin/laropiprant and simvastatin on lipoprotein subclasses in patients with dyslipidemia,” published in the Journal of Clinical Lipidology, researchers conducted a predefined exploratory analysis of a large, double-blind, randomized active-controlled study that previously evaluated the effectiveness of the anti-flushing drug Laropiprant (LRPT) when combined with extended release niacin (ERN) and simvastatin (SIM). Despite its proven cardioprotective benefits, niacin has not been well tolerated due to the unpleasant side effect of flushing. LRPT proved to be well tolerated in the large randomized study, and ERN/LRPT plus simvastatin significantly improved patients’ lipid profile compared with ERN/LRPT and simvastatin alone.
Ballantyne et al. examined the individual and combined effects of ERN/LRPT and SIM on lipoprotein subfractions as isolated by the VAP Cholesterol Test methodology, which separates lipoprotein fractions based on their inherent molecular properties (size and density). Researchers evaluated the effects of: ERN/LRPT plus SIM; ERN/LRPT; and SIM alone on percent change from baseline to week 12 in cholesterol associated lipoproteins. Researchers reported:
- Significant baseline reductions in LDL and dense LDL subclasses;
- Significant baseline increases in high denisty lipoprotein (HDL) with larger increases in HDL2; and
- Significant baselines reductions in triglyceride rich lipoproteins VLDL1+2, VLDL3 and IDL.
Lead author Christie Ballantyne, M.D., said previous studies that examined the effects of niacin on lipid subclasses have shown that niacin favorably shifts the ratio of small to large HDL and LDL particles toward a more cardioprotective distribution. However, he said this marks the first use of the VAP Test for such an analysis.
“To our knowledge, we are the first to use the VAP Test to compare the individual and combined effects of niacin and statin on lipoprotein subfractions,” said Ballantyne. “By isolating a broad array of lipoprotein subfractions, we were able to quantify the cholesterol within each lipoprotein fraction, enabling a more precise picture of dyslipidemia and the effects of medications on these lipoprotein parameters.”
Lipoproteins isolated by the VAP Test for the study included: VLDL, VLDL subclasses (VLDL1+2, VLDL3); IDL; LDL-R (Real LDL, excluding the contribution of IDL and Lp(a) typically included in standard LDL measurements); LDL subclasses (LDL1, LDL2, LDL3, LDL4); Lp(a); HDL and HDL subclasses (HDL2, HDL3).
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