To isolate lipoprotein particles from coeluting proteins in the collected fractions, we used a commercially available synthetic calcium silicate hydrate called Lipid Removal Agent (Supelco). This compound, developed for the removal of lipids in biopharmaceutical production, tightly binds lipids and lipoproteins. In a centrifuge tube, 45 μg of CSH (from 100 mg/mL stock solution in 50 mM ammonium bicarbonate) per 1 μg of PL in 400 μL of fraction were mixed gently for 30 min at room temperature. The CSH was then pelleted by centrifugation (~2200× g for 2 min) in a minicentrifuge (Fisher) and the supernatant containing lipid-free plasma proteins was removed. The CSH was then washed with 50 mM ammonium bicarbonate (AB). All PL-containing fractions from each subject’s FPLC separation were carried through this process individually.