Evacetrapib reduces preß-1 HDL in patients with atherosclerotic cardiovascular disease or diabetes.

BACKGROUND AND AIMS: Cholesteryl ester transfer protein (CETP) inhibitor-mediated induction of HDL-cholesterol has no effect on the protection from cardiovascular disease (CVD). However, the mechanism is still unknown. Data on the effects of this class of drugs on subclasses of HDL are either limited or insufficient. In this study, we investigated the effect of evacetrapib, a CETP inhibitor, on subclasses of HDL in patients with atherosclerotic cardiovascular disease or diabetes. METHODS: Baseline and 3-month post-treatment samples from atorvastatin 40 mg plus evacetrapib 130 mg (n = 70) and atorvastatin 40 mg plus placebo (n = 30) arms were used for this purpose. Four subclasses of HDL (large HDL, medium HDL, small HDL, and preß-1 HDL) were separated according to their size and quantified by densitometry using a recently developed native polyacrylamide gel electrophoresis (PAGE) system. RESULTS: Relative to placebo, while evacetrapib treatment dramatically increased large HDL and medium HDL subclasses, it significantly reduced small HDL (27%) as well as preß-1 HDL (36%) particles. Evacetrapib treatment reduced total LDL, but also resulted in polydisperse LDL with LDL particles larger and smaller than the LDL subclasses of the placebo group. CONCLUSION: Evacetrapib reduced preß-1 HDL and small HDL in patients with ASCVD or diabetes on statin. Preß-1 HDL and medium HDL are negatively interrelated. The results could give a clue to understand the effect of CETP inhibitors on cardiovascular outcomes.

ApoA-I mimetic peptides promote pre-ß HDL formation in vivo causing remodeling of HDL and triglyceride accumulation at higher dose.

Reverse cholesterol transport promoted by HDL-apoA-I is an important mechanism of protection against atherosclerosis. We have previously identified apoA-I mimetic peptides by synthesizing analogs of the 22 amino acid apoA-I consensus sequence (apoA-I(cons)) containing non-natural aliphatic amino acids. Here we examined the effect of different aliphatic non-natural amino acids on the structure-activity relationship (SAR) of apoA-I mimetic peptides. These novel apoA-I mimetics, with long hydrocarbon chain (C(5-8)) amino acids incorporated in the amphipathic α helix of the apoA-I(cons), have the following properties: (i) they stimulate in vitro cholesterol efflux from macrophages via ABCA1; (ii) they associate with HDL and cause formation of pre-ß HDL particles when incubated with human and mouse plasma; (iii) they associate with HDL and induce pre-ß HDL formation in vivo, with a corresponding increase in ABCA1-dependent cholesterol efflux capacity ex vivo; (iv) at high dose they associate with VLDL and induce hypertriglyceridemia in mice. These results suggest our peptide design confers activities that are potentially anti-atherogenic. However a dosing regimen which maximizes their therapeutic properties while minimizing adverse effects needs to be established.

Anti-inflammatory and recycling properties of an apolipoprotein mimetic peptide, Ac-hE18A-NH(2).

Apolipoprotein E (apoE) exerts prominent anti-inflammatory effects and undergoes recycling by target cells. We previously reported that the peptide Ac-hE18A-NH(2), composed of the receptor binding domain (LRKLRKRLLR) of apoE covalently linked to the Class A amphipathic peptide 18A, dramatically lowers plasma cholesterol and lipid hydroperoxides and enhances paraoxonase activity in dyslipidemic animal models. The objective of this study was to determine whether this peptide, analogous to apoE, exerts anti-inflammatory effects and undergoes recycling under in vitro conditions. Pulse chase studies using [(125)I]-Ac-hE18A-NH(2) in THP-1 derived macrophages and HepG2 cells showed greater amounts of intact peptide in the cells at later time points indicating recycling of the peptide. Ac-hE18A-NH(2) induced a 2.5-fold increase in prebeta-HDL in the conditioned media of HepG2 cells. This effect persisted for 3 days after removal of the peptide from culture medium. Ac-hE18A-NH(2) also induced the secretion of cell surface apoE from THP-1 macrophages. In addition, the peptide increased cholesterol efflux from THP-1 cells by an ABCA1 independent mechanism. Moreover, Ac-hE18A-NH(2) inhibited LPS-induced vascular cell adhesion molecule-1 (VCAM-1) expression, and reduced monocyte adhesion in human umbilical vein endothelial cells (HUVECs). It also reduced the secretion of interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) from THP-1 macrophages even when administered post-LPS and abolished the 18-fold increase in LPS-induced mRNA levels for MCP-1 in THP-1 cells. Taken together, these results suggest that addition of the putative apoE receptor-domain to the Class A amphipathic peptide 18A results in a peptide that, similar to apoE, recycles, thus enabling the potentiation and prolongation of its anti-atherogenic and anti-inflammatory effects. Such a peptide has great potential as a therapeutic agent in the management of atherosclerosis and other inflammatory diseases.

An apolipoprotein A-I mimetic dose-dependently increases the formation of prebeta1 HDL in human plasma.

Prebeta1 HDL is the initial plasma acceptor of cell-derived cholesterol in reverse cholesterol transport. Recently, small amphipathic peptides composed of D-amino acids have been shown to mimic apolipoprotein A-I (apoA-I) as a precursor for HDL formation. ApoA-I mimetic peptides have been proposed to stimulate the formation of prebeta1 HDL and increase reverse cholesterol transport in apoE-null mice. The existence of a monoclonal antibody (MAb 55201) and a corresponding ELISA method that is selective for the detection of the prebeta(1) subclass of HDL provides a means of establishing a correlation between apoA-I mimetic dose and prebeta1 HDL formation in human plasma. Using this prebeta1 HDL ELISA, we demonstrate marked apoA-I mimetic dose-dependent prebeta1 HDL formation in human plasma. These results correlated with increases in band density of the plasma prebeta1 HDL, when observed by Western blotting, as a function of increased apoA-I mimetic concentration. Increased prebeta1 HDL formation was observed after as little as 1 min and was maximal within 1 h. Together, these data suggest that a high-throughput prebeta1 HDL ELISA provides a way to quantitatively measure a key component of the reverse cholesterol transport pathway in human plasma, thus providing a possible method for the identification of apoA-I mimetic molecules.

The effects of orlistat and fenofibrate, alone or in combination, on high-density lipoprotein subfractions and pre-beta1-HDL levels in obese patients with metabolic syndrome.

OBJECTIVE: We assessed the effect of orlistat and fenofibrate, alone or in combination, on plasma high-density lipoprotein (HDL) subfractions and plasma pre-beta1-HDL levels in overweight and obese subjects with metabolic syndrome (MetS). METHODS: Patients (n = 89) were prescribed a low-fat low-calorie diet and were randomly allocated to receive orlistat 120 mg three times daily (O group), micronized fenofibrate 200 mg/day (F group) or both (OF group) for 6 months. HDL subfractions were determined using a polyacrylamide gel tube electrophoresis method and pre-beta1-HDL levels using enzyme-linked immunoabsorbent assay. RESULTS: We observed a significant change of high-density lipoprotein cholesterol (HDL-C) levels only in the F group (+3%, p < 0.05). Large HDL-C levels were significantly increased and small HDL-C levels were significantly reduced with O administration. In F group we observed a significant increase of small HDL-C levels. No significant change of large or small HDL-C levels was observed with combination treatment. We observed a significant increase of pre-beta1-HDL levels in all groups, which was significantly greater in OF group compared with O or F monotherapy. CONCLUSION: OF combination increased the antiatherogenic pre-beta1-HDL levels in overweight and obese patients with MetS. Furthermore, OF combination counterbalanced the reduction of small HDL-C levels observed with orlistat monotherapy.