Biochemical and Functional Characterization of Charge-Defined Subfractions of High-Density Lipoprotein From Normal Adults

High-density lipoprotein (HDL) is regarded as atheroprotective because it provides antioxidant and anti-inflammatory benefits and plays an important role in reverse cholesterol transport. In this paper, we outline a novel methodology for studying the heterogeneity of HDL. Using anion-exchange chromatography, we separated HDL from 6 healthy individuals into five subfractions (H1 through H5) with increasing charge and evaluated the composition and biologic activities of each subfraction. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis showed that apolipoprotein (apo) AI and apoAII were present in all 5 subfractions; apoCI was present only in H1, and apoCIII and apoE were most abundantly present in H4 and H5. HDL-associated antioxidant enzymes such as lecithin-cholesterol acyltransferase, lipoprotein-associated phospholipase A₂, and paraoxonase 1 were most abundant in H4 and H5. Lipoprotein isoforms were analyzed in each subfraction by using matrix-assisted laser desorption-time-of-flight mass spectrometry. To quantify other proteins in the HDL subfractions, we used the isobaric tags for the relative and absolute quantitation approach followed by nanoflow liquid chromatography–tandem mass spectrometry analysis. Most antioxidant proteins detected were found in H4 and H5. The ability of each subfraction to induce cholesterol efflux from macrophages increased with increasing HDL electronegativity, with the exception of H5, which promoted the least efflux activity. In conclusion, anion-exchange chromatography is an attractive method for separating HDL into subfractions with distinct lipoprotein compositions and biologic activities. By comparing the properties of these subfractions, it may be possible to uncover HDL-specific proteins that play a role in disease

Using one-way analysis of variance and post-hoc multiple comparisons with Bonferroni’s correction to investigate the differences of skin AF levels, and FMD values between the non-CKD, uremia with DM, and uremia without DM groups.

<p>(a) The skin AF level was significantly lower in the non-CKD group than in the uremia group (P<0.01). However, the skin AF level was similar between the uremia with or without DM groups. (b) The FMD value was significantly higher in the non-CKD group than in the uremia group (P<0.01). However, the FMD value was similar between the uremia with or without DM groups.</p

Receiver operating curves (ROC) of AGE for predicting abnormal FMD in the (a) hemodialysis group, and (b) the non-CKD group.

<p>Receiver operating curves (ROC) of AGE for predicting abnormal FMD in the (a) hemodialysis group, and (b) the non-CKD group.</p