The majority of lipoprotein lipase in plasma is bound to remnant lipoproteins: A new definition of remnant lipoproteins

Abstract

It is suggested that during lipolysis in vivo, the endothelial bound LPL dimers generates RLP, forming circulating RLP-LPL complexes in an inactive form that subsequently binds and initiates receptor-mediated catabolism.

MicroRNA-182 Promotes Lipoprotein Lipase Expression and Atherogenesisby Targeting Histone Deacetylase 9 in Apolipoprotein E-Knockout Mice

“…Moreover, administration of AG increased plasma low-density lipo- protein 1 (LRP-1), scavenger receptor A1 (SR-A1), and very low-density lipoprotein receptor (VLDLR), to heparin-like substances. 37 In addition, overexpression of macrophage-derived LPL contributes to anchoring some atherogenic lipoproteins, such as LDL and oxLDL, thereby promoting cellular lipid uptake and accumulation. In the present study, HDAC9 was identified as a direct target of miR-182, which is consistent with a recent report.…”

A Proposal of The New Mechanism on Remnant Lipoprotein Formation and Clearance after Food Intake

“…We previously reported that the particle size of remnant lipoproteins were inversely correlated with LPL activity and concentration [36]. Large RLP particles carry a significantly less LPL concentration per particle compared to small RLP particles, as shown by the LPL/RLP-TG ratio [34,35,41]. It is because unchanged concentration of LPL on the endothelium after food intake has to hydrolyze significantly increased CM and VLDL particles.…”

“…Using the immunoaffinity separation method of remnant lipoproteins, we found that the majority of LPL in plasma presented in RLP fraction which we isolated as remnant lipoproteins for many years [35].…”

“…content and LPL activity in RLP particles, we calculated the LPL/RLP-TG ratio as Felts et al proposed [49]. For example, when LPL bound to RLP increased significantly after heparin administration, RLP-TG decreased significantly as the result of LPL-RLP interaction [35]. Therefore, its interaction correlation was expressed as LPL/RLP-TG ratio or LPL/TG ratio (Table 1 : Fifty four Japanese volunteers for the oral fat load test who were without any CVD, diabetes or other distinctly evident diseases (30 males and 24 females, aged 28-63 y, Table 2: Seventy nine relatively healthy young US volunteers (some were overweight or obese) in a male (n=40) and female (n=39) population (Caucasian 45, Asian 10, Hispanic 9, African American 7, others 8) with a median age of 24).…”

“…Those results provided a new insight of LPL and remnant lipoprotein interaction in the circulating plasma. Therefore, we have proposed that the TG-rich lipoproteins bound to LPL dimers with inactive form is the new definition of remnant lipoproteins [35].…”