CETP expression reverses the reconstituted HDL-induced increase in VLDL

Area of Science:

• Lipid metabolism
• Cardiovascular research
• Pharmacology

Background:

• Reconstituted HDL (rHDL) infusion shows potential for atherosclerosis regression in humans.
• Mouse studies indicate rHDL can negatively impact VLDL levels, a discrepancy noted in human studies.
• Human expression of cholesteryl ester transfer protein (CETP) may explain the difference in rHDL effects between species.

Purpose of the Study:

• To investigate the role of CETP in modulating the effects of rHDL on VLDL metabolism.
• To utilize APOE*3-Leiden (E3L) mice, a model for human-like lipoprotein metabolism, to study CETP's influence.

Main Methods:

• Comparison of rHDL effects on VLDL metabolism in E3L mice versus E3L mice with human CETP (E3L.CETP mice).
• Analysis of plasma VLDL-C and triglyceride (TG) levels at 1 and 24 hours post-rHDL injection.
• Assessment of VLDL-TG production and LPL-mediated hydrolysis pathways.

Main Results:

• In E3L mice, rHDL transiently increased VLDL-C and TG, an effect absent in E3L.CETP mice, indicating CETP prevents initial VLDL elevation.
• CETP prevented the initial VLDL increase by mitigating competition between rHDL and VLDL for LPL-mediated TG hydrolysis.
• In E3L mice, rHDL later increased VLDL-C and TG due to enhanced hepatic VLDL-TG production, while E3L.CETP mice showed decreased VLDL levels.

Conclusions:

• CETP plays a protective role against rHDL-induced increases in VLDL.
• Findings suggest caution when interpreting rHDL efficacy in CETP-deficient mouse models.
• Combining rHDL therapy with CETP-activity-reducing agents may be inadvisable for treating atherogenic dyslipidemia.