CER-001 ameliorates lipid profile and kidney disease in a mouse model of familial LCAT deficiency

OBJECTIVE

CER-001 is an HDL mimetic that has been tested in different pathological conditions, but never with LCAT deficiency. This study was designed to investigate whether the absence of LCAT affects the catabolic fate of CER-001, and to evaluate the effects of CER-001 on kidney disease associated with LCAT deficiency.

METHODS

Lcat^-/- and wild-type mice received CER-001 (2.5, 5, 10 mg/kg) intravenously for 2 weeks. The plasma lipid/ lipoprotein profile and HDL subclasses were analyzed. In a second set of experiments, Lcat^-/- mice were injected with LpX to induce renal disease and treated with CER-001 and then the plasma lipid profile, lipid accumulation in the kidney, albuminuria and glomerular podocyte markers were evaluated.

RESULTS

In Lcat^-/- mice a decrease in total cholesterol and triglycerides, and an increase in HDL-c was observed after CER-001 treatment. While in wild-type mice CER-001 entered the classical HDL remodeling pathway, in the absence of LCAT it disappeared from the plasma shortly after injection and ended up in the kidney. In a mouse model of renal disease in LCAT deficiency, treatment with CER-001 at 10 mg/kg for one month had beneficial effects not only on the lipid profile, but also on renal disease, by limiting albuminuria and podocyte dysfunction.

CONCLUSIONS

Treatment with CER-001 ameliorates the dyslipidemia typically associated with LCAT deficiency and more importantly limits renal damage in a mouse model of renal disease in LCAT deficiency. The present results provide a rationale for using CER-001 in FLD patients.

Effect of Serial Infusions of CER-001, a Pre-β High-Density Lipoprotein Mimetic, on Coronary Atherosclerosis in Patients Following Acute Coronary Syndromes in the CER-001 Atherosclerosis Regression Acute Coronary Syndrome Trial: A Randomized Clinical Trial

Importance

CER-001 is a negatively charged, engineered pre-β high-density lipoprotein (HDL) mimetic containing apolipoprotein A-I and sphingomyelin. Preliminary studies demonstrated favorable effects of CER-001 on cholesterol efflux and vascular inflammation. A post hoc reanalysis of a previously completed study of intravenous infusion of CER-001, 3 mg/k, showed that the intravenous infusion in patients with a high coronary plaque burden promoted regression as assessed by intravascular ultrasonography.

Objective

To determine the effect of infusing CER-001 on coronary atherosclerosis progression in statin-treated patients.

Design, Setting, and Participants

A double-blind, randomized, multicenter trial evaluating the effect of 10 weekly intravenous infusions of CER-001, 3 mg/kg, (n = 135) or placebo (n = 137) in patients with an acute coronary syndrome (ACS) and baseline percent atheroma volume (PAV) greater than 30% in the proximal segment of an epicardial artery by intravascular ultrasonography. The study included 34 academic and community hospitals in Australia, Hungary, the Netherlands, and the United States in patients with ACS presenting for coronary angiography. Patients were enrolled from August 15, 2015, to November 19, 2016.

Interventions

Participants were randomized to receive weekly CER-001, 3 mg/kg, or placebo for 10 weeks in addition to statins.

Main Outcomes and Measures

The primary efficacy measure was the nominal change in PAV from baseline to day 78 measured by serial intravascular ultrasonography imaging. The secondary efficacy measures were nominal change in normalized total atheroma volume and percentage of patients demonstrating plaque regression. Safety and tolerability were also evaluated.

Results

Among 293 patients (mean [SD] age, 59.8 [9.4] years; 217 men [79.8%] and 261 white race/ethnicity [96.0%]), 86 (29%) had statin prior use prior to the index ACS and 272 (92.8%) had evaluable imaging at follow-up. The placebo and CER-001 groups had similar posttreatment median levels of low-density lipoprotein cholesterol (74 mg/dL vs 79 mg/dL; P = .15) and high-density lipoprotein cholesterol (43 mg/dL vs 44 mg/dL; P = .66). The primary efficacy measure, PAV, decreased 0.41% with placebo (P = .005 compared with baseline), but not with CER-001 (-0.09%; P = .67 compared with baseline; between group differences, 0.32%; P = .15). Similar percentages of patients in the placebo and CER-001 groups demonstrated regression of PAV (57.7% vs 53.3%; P = .49). Infusions were well tolerated, with no differences in clinical and laboratory adverse events observed between treatment groups.

Conclusions and Relevance

Infusion of CER-001 did not promote regression of coronary atherosclerosis in statin-treated patients with ACS and high plaque burden.

Trial Registration

ClinicalTrials.gov Identifier: NCT2484378.

Regression of coronary atherosclerosis with infusions of the high-density lipoprotein mimetic CER-001 in patients with more extensive plaque burden

BACKGROUND

CER-001 is an engineered pre-beta high-density lipoprotein (HDL) mimetic, which rapidly mobilizes cholesterol. Infusion of CER-001 3 mg/kg exhibited a potentially favorable effect on plaque burden in the CHI-SQUARE (Can HDL Infusions Significantly Quicken Atherosclerosis Regression) study. Since baseline atheroma burden has been shown as a determinant for the efficacy of HDL infusions, the degree of baseline atheroma burden might influence the effect of CER-001.

METHODS

CHI-SQUARE compared the effect of 6 weekly infusions of CER-001 (3, 6 and 12 mg/kg) vs. placebo on coronary atherosclerosis in 369 patients with acute coronary syndrome (ACS) using serial intravascular ultrasound (IVUS). Baseline percent atheroma volume (B-PAV) cutoff associated with atheroma regression following CER-001 infusions was determined by receiver-operating characteristics curve analysis. 369 subjects were stratified according to the cutoff. The effect of CER-001 at different doses was compared to placebo in each group.

RESULTS

A B-PAV ≥30% was the optimal cutoff associated with PAV regression following CER-001 infusions. CER-001 induced PAV regression in patients with B-PAV ≥30% but not in those with B-PAV <30% (-0.45%±2.65% vs. +0.34%±1.69%, P=0.01). Compared to placebo, the greatest PAV regression was observed with CER-001 3mg/kg in patients with B-PAV ≥30% (-0.96%±0.34% vs. -0.25%±0.31%, P=0.01), whereas there were no differences between placebo (+0.09%±0.36%) versus CER-001 in patients with B-PAV <30% (3 mg/kg; +0.41%±0.32%, P=0.39; 6 mg/kg; +0.27%±0.36%, P=0.76; 12 mg/kg; +0.32%±0.37%, P=0.97).

CONCLUSIONS

Infusions of CER-001 3 mg/kg induced the greatest atheroma regression in ACS patients with higher B-PAV. These findings identify ACS patients with more extensive disease as most likely to benefit from HDL mimetic therapy.

Effect of serial infusions of reconstituted high-density lipoprotein (CER-001) on coronary atherosclerosis: rationale and design of the CARAT study

BACKGROUND

High-density lipoprotein (HDL) is believed to have atheroprotective properties, but an effective HDL-based therapy remains elusive. Early studies have suggested that infusion of reconstituted HDL promotes reverse cholesterol transport and vascular reactivity. The CER-001 Atherosclerosis Regression Acute Coronary Syndrome Trial (CARAT) is investigating the impact of infusing an engineered pre-beta HDL mimetic containing sphingomyelin (SM) and dipalmitoyl phosphatidlyglycerol (CER-001) on coronary atheroma volume in patients with a recent acute coronary syndrome (ACS).

METHODS

The CARAT is a phase 2, multicenter trial in which 292 patients with an ACS undergoing intracoronary ultrasonography and showing percent atheroma volume (PAV) greater than 30% are randomly assigned to treatment with ten infusions of CER-001 3 mg/kg or matching placebo, administered at weekly intervals. Intracoronary ultrasonography is repeated at the end of the treatment period.

RESULTS

The primary endpoint is the nominal change in PAV. Safety and tolerability will also be evaluated.

CONCLUSIONS

CARAT will establish whether serial 3 mg/kg infusions of an engineered pre-beta HDL mimetic containing SM and dipalmitoyl phosphatidlyglycerol (CER-001) will regress atherosclerotic plaque in patients with a recent ACS.

Effect of open-label infusion of an apoA-I-containing particle (CER-001) on RCT and artery wall thickness in patients with FHA

Reverse cholesterol transport (RCT) contributes to the anti-atherogenic effects of HDL. Patients with the orphan disease, familial hypoalphalipoproteinemia (FHA), are characterized by decreased tissue cholesterol removal and an increased atherogenic burden. We performed an open-label uncontrolled proof-of-concept study to evaluate the effect of infusions with a human apoA-I-containing HDL-mimetic particle (CER-001) on RCT and the arterial vessel wall in FHA. Subjects received 20 infusions of CER-001 (8 mg/kg) during 6 months. Efficacy was assessed by measuring (apo)lipoproteins, plasma-mediated cellular cholesterol efflux, fecal sterol excretion (FSE), and carotid artery wall dimension by MRI and artery wall inflammation by (18)F-fluorodeoxyglucose-positron emission tomography/computed tomography scans. We included seven FHA patients: HDL-cholesterol (HDL-c), 13.8 [1.8-29.1] mg/dl; apoA-I, 28.7 [7.9-59.1] mg/dl. Following nine infusions in 1 month, apoA-I and HDL-c increased directly after infusion by 27.0 and 16.1 mg/dl (P = 0.018). CER-001 induced a 44% relative increase (P = 0.018) in in vitro cellular cholesterol efflux with a trend toward increased FSE (P = 0.068). After nine infusions of CER-001, carotid mean vessel wall area decreased compared with baseline from 25.0 to 22.8 mm(2) (P = 0.043) and target-to-background ratio from 2.04 to 1.81 (P = 0.046). In FHA-subjects, CER-001 stimulates cholesterol mobilization and reduces artery wall dimension and inflammation, supporting further evaluation of CER-001 in FHA patients.

Effects of the high-density lipoprotein mimetic agent CER-001 on coronary atherosclerosis in patients with acute coronary syndromes: a randomized trial

Aim

High-density lipoproteins (HDLs) have several potentially protective vascular effects. Most clinical studies of therapies targeting HDL have failed to show benefits vs. placebo.

Objective

To investigate the effects of an HDL-mimetic agent on atherosclerosis by intravascular ultrasonography (IVUS) and quantitative coronary angiography (QCA).

Design and setting

A prospective, double-blinded, randomized trial was conducted at 51 centres in the USA, the Netherlands, Canada, and France. Intravascular ultrasonography and QCA were performed to assess coronary atherosclerosis at baseline and 3 (2–5) weeks after the last study infusion.

Patients

Five hundred and seven patients were randomized; 417 and 461 had paired IVUS and QCA measurements, respectively.

Intervention

Patients were randomized to receive 6 weekly infusions of placebo, 3 mg/kg, 6 mg/kg, or 12 mg/kg CER-001.

Main outcome measures

The primary efficacy parameter was the nominal change in the total atheroma volume. Nominal changes in per cent atheroma volume on IVUS and coronary scores on QCA were also pre-specified endpoints.

Results

The nominal change in the total atheroma volume (adjusted means) was −2.71, −3.13, −1.50, and −3.05 mm³ with placebo, CER-001 3 mg/kg, 6 mg/kg, and 12 mg/kg, respectively (primary analysis of 12 mg/kg vs. placebo: P = 0.81). There was also no difference among groups for the nominal change in per cent atheroma volume (0.02, −0.02, 0.01, and 0.19%; nominal P = 0.53 for 12 mg/kg vs. placebo). Change in the coronary artery score was −0.022, −0.036, −0.022, and −0.015 mm (nominal P = 0.25, 0.99, 0.55), and change in the cumulative coronary stenosis score was −0.51, 2.65, 0.71, and −0.77% (compared with placebo, nominal P = 0.85 for 12 mg/kg and nominal P = 0.01 for 3 mg/kg). The number of patients with major cardiovascular events was 10 (8.3%), 16 (13.3%), 17 (13.7%), and 12 (9.8%) in the four groups.

Conclusion

CER-001 infusions did not reduce coronary atherosclerosis on IVUS and QCA when compared with placebo. Whether CER-001 administered in other regimens or to other populations could favourably affect atherosclerosis must await further study.

Name of the trial registry: Clinicaltrials.gov; Registry's URL: http://clinicaltrials.gov/ct2/show/NCT01201837?term=cer-001&rank=2; Trial registration number: NCT01201837.

Metabolomics applications of FT-ICR mass spectrometry

Metabolomics, also known as Metabolic Profiling, is an emerging discipline under the umbrella concept of systems biology. The goal of metabolomics is to know and understand the concentrations and fluxes of endogenous metabolites within a living biological system under study. General tools are being developed for the rapid measurement of many metabolites in a single experiment, most of which are mass spectrometric methods. FT-ICR has unique advantages, as a mass spectrometric method, in this regard. Applications of FT-ICR to metabolomics analyses will be discussed and reviewed in the context of the single publication currently available.

alpha-Cycloalkyl-substituted omega-keto-dicarboxylic acids as lipid regulating agents

A series of cycloalkyl-substituted oxo-alkanedicarboxylic acids have been prepared by the TosMIC methodology departing from haloalkyl-substituted cycloalkylcarboxylic esters. cyclopropyl derivatives showed IC(50) activity in the 0.3-1.0 microM range on the de novo incorporation of radiolabeled acetate into lipids in primary cultures of rat hepatocytes, and they showed lipid-regulating properties when tested in vivo in female obese Zucker fatty rats.

The amphipathic helix concept: length effects on ideally amphipathic LiKj(i=2j) peptides to acquire optimal hemolytic activity

In a minimalist approach to modeling lytic toxins, amphipathic peptides of LiKj with i=2j composition and whose length varies from 5 to 22 residues were studied for their ability to induce hemolysis and lipid vesicle leakage. Their sequences were designed to generate ideally amphipathic alpha helices with a single K residue per putative turn. All the peptides were lytic, their activities varying by more than a factor of 103 from the shortest 5-residue-long peptide (5-mer) to the longest 22-mer. However, there was no monotonous increase versus length. The 15-mer was as active as the 22-mer and even more than melittin which is used as standard. Partition coefficients from the buffer to the membrane increased in relation to length up to 12 residues, then weakly decreased to reach a plateau, while they were expected to increase monotonously with peptide length and hydrophobicity as revealed from HPLC retention times. Fluorescence labeling by a dansyl group at the N-terminus, or by a W near the CO-terminus, show that up to 12 residues, the peptides were essentially monomeric while longer peptides strongly aggregated in the solution. Lipid affinity was then controlled by peptide length and was found to be limited by folding and self-association in buffer. The lytic activity resulted both from lipid affinity, which varied by a factor of 20-fold, and from efficiency in disturbing the membrane when bound, the latter steeply and monotonously increasing with length. The 15-residue-long peptide, KLLKLLLKLLLKLLK, had the optimal size for highest lytic activity. The shallow location of the fluorescent labels in the lipids is further evidence for a model of peptides remaining flat at the interface.

The amphipathic alpha-helix concept. Application to the de novo design of ideally amphipathic Leu, Lys peptides with hemolytic activity higher than that of melittin

An original series of 12- to 22-residue-long peptides was developed, they are only constituted by apolar Leu and charged Lys residues periodically located in the sequence in order to general ideal highly amphipathic alpha-helices. By circular dichroism, the peptides are proven to be mainly alpha-helical in organic and aqueous solvents and in the presence of lipids. The peptides are highly hemolytic, their activity varies according to the peptide length. The 15-, 20-, and 22-residue-long-peptides have LD50 approximately 5 x 10(-8) M for 10(7) erythrocytes, i.e. they are 5-10 times more active than melittin, and are indeed several orders of magnitude more active than magainin or mastoparan.

Membrane insertion of the pore-forming domain of colicin A. A spectroscopic study

In order to gain some insight into the mechanism of insertion into membranes of the pore-forming domain of colicin A and the structure of its membrane-bound form, circular dichroism (in the near and far ultraviolet), fluorescence and ultraviolet spectroscopy experiments were carried out. Because the structure of the water-soluble form of this fragment has been determined by X-ray crystallography, these spectroscopic methods provided valuable information on the secondary structure and the environment of aromatic residues within the two forms of the peptide. These results strongly suggest that the pore-forming domain of colicin A does not undergo drastic unfolding upon insertion into membrane. The conformational change associated with this process is triggered by the negatively charged lipids and probably consists of a reorientation of helix pairs with respect to each other. Exposure of the aromatic residues to the aqueous phase decreases on binding to lipids whilst the exposure of the tryptophans to the membrane phase increases. This cannot occur without a reorientation of helices 3-10. All data from this study support the model presented previously in which the known crystal structure opens like an 'umbrella' inserting the hydrophobic hairpin (helix 8-9) perpendicular to the membrane plane and the helical pair 1-2 and the domain containing the three tryptophans (helices 3-7) lying more or less parallel to the membrane plane. Lipids are bound more tightly to the protein at acidic pH than at neutral pH although a similar lipid protein complex is formed with 1,2-dimyristoyl-sn-glycero(3)-phospho(1)- -sn-glycerol at both pH values.

Interaction of the pore-forming domain of colicin A with phospholipid vesicles

The interaction of the 20-kDa pore-forming domain of colicin A with phospholipid vesicles was investigated by gel permeation chromatography, analytical centrifugation, and electron microscopy. Under the experimental conditions of this study, this peptide was found to interact only with vesicles containing negatively charged phospholipids. It forms a well-defined disklike complex with phosphatidylglycerols with a preference for those containing 12-14 atoms of carbon in their fatty acid chain. This complex has a diameter of 120 A and is about one bilayer thick. It contains nine molecules of peptide and is formed both at acidic pH (pH 5.0) and at neutral pH (pH 7.2).

Effects of bee venom melittin on the order and dynamics of dimyristoylphosphatidylcholine unilamellar and multilamellar vesicles

The effects of bee venom melittin on the order and dynamics of dimyristoylphosphatidylcholine unilamellar and multilamellar vesicles at a protein-to-lipid molar ratio of 1:60 have been investigated by employing the techniques of nanosecond emission anisotropy with 1,6-diphenyl-1,3,5-hexatriene as the fluorescent probe, enhancement by polar groups of the weakly allowed 0-0 vibronic transition in the fluorescence spectrum of pyrene, and Raman spectroscopy. The emission anisotropy results, which are found to be consistent with the wobble-in-cone model, show that the protein induces an increase in the order parameter, S, of the acyl chains of unilamellar vesicles below, at, and above their phase transition temperature, Tt, and it decreases strongly the diffusion rate, Dw, only below Tt. On the other hand, for multilamellar vesicles, the protein induces a decrease in S only at Tt and does not affect Dw. These effects are consistent with the observed changes in the degree of enhancement of the 0-0 vibronic transition of pyrene. Moreover, the protein broadens the thermal transition profile of multilamellar vesicles but sharpens dramatically that of unilamellar vesicles and fuses them without changing significantly the Tt in either case. On the other hand, the Raman data detect a decrease in the inter- and intramolecular order of the acyl chains of multilamellar vesicles below Tt and a decrease of only the former Tt. This disparity between the Raman and the nanosecond emission anisotropy data is discussed in terms of differences in the time scales of the two techniques and in the state of aggregation of the lipid-bound melittin. The data for the enhancement of the 0-0 vibronic transition of pyrene suggest that, for a melittin-to-lipid ratio of 1:60, the size or structure of channels formed in the bilayer by melittin does not allow the penetration of a neutral molecule the size of pyrene deeply into the bilayer.

Study of the effect of melittin on the thermotropism of dipalmitoylphosphatidylcholine by Raman spectroscopy

The effect of amphiphilic toxin melittin (Mel) on the thermotropic behavior of dipalmitoylphosphatidylcholine (DPPC) has been studied by Raman spectroscopy. The spectra show that for complexes that were incubated above 40 degrees C, melittin does not penetrate DPPC bilayers in the gel state as an intrinsic protein since the conformation of the lipid acyl chains is just slightly perturbed by the toxin. Instead, at the DPPC/Mel molar ratios investigated (Ri = 5 and 15), Raman results suggest the formation of discoidal particles as complexes of apolipoproteins with phosphatidylcholines. These lipid/protein assemblies are characterized by a high conformational order, low intermolecular chain-chain interactions due to the size of the particles, and a low cooperativity of the gel to liquid-crystalline transition. The latter is biphasic for samples studied. It is believed that aggregation of these particles into larger ones occurs when the bilayers become less stable at higher temperature and that melittin is partially embedded into the hydrophobic core of the larger lipid/protein units. The freezing of the dispersion at approximately 0 degrees C also causes a reversible aggregation of the particles that leads to the formation of domains in which the interchain interactions are very similar to that of the pure lipid. The small particles of DPPC/Mel are also metastable, and with time, they form larger aggregates from which melittin is expulsed.

Morphological changes of phosphatidylcholine bilayers induced by melittin: vesicularization, fusion, discoidal particles

Morphological changes induced by the melittin tetramer on bilayers of egg phosphatidylcholine and dipalmitoylphosphatidylcholine have been studied by quasi-elastic light scattering, gel filtration and freeze-fracture electron microscopy. It is concluded that melittin similarly binds and changes the morphology of both single and multilamellar vesicles, provided that their hydrocarbon chains have a disordered conformation, i.e., at temperatures higher than that of the transition, Tm. When the hydrocarbon chains are ordered (gel phase), only small unilamellar vesicles are morphologically affected by melittin. However after incubation at T greater than Tm, major structural changes are detected in the gel phase, regardless of the initial morphology of the lipids. Results from all techniques agree on the following points. At low melittin content, phospholipid-to-peptide molar ratios, Ri greater than 30, heterogeneous systems are observed, the new structures coexisting with the original ones. For lipids in the fluid phase and Ri greater than 12, the complexes formed are large unilamellar vesicles of about 1300 +/- 300 A diameter and showing on freeze-fracture images rough fracture surfaces. For lipids in the gel phase, T less than Tm after passage above Tm, and for 5 less than Ri less than 50, disc-like complexes are observed and isolated. They have a diameter of 235 +/- 23 A and are about one bilayer thick; their composition corresponds to one melittin for about 20 +/- 2 lipid molecules. It is proposed that the discs are constituted by about 1500 lipid molecules arranged in a bilayer and surrounded by a belt of melittin in which the mellitin rods are perpendicular to the bilayer. For high amounts of melittin, Ri less than 2, much smaller and more spherical objects are observed. They are interpreted as corresponding to lipid-peptide co-micelles in which probably no more bilayer structure is left. It is concluded that melittin induces a reorganization of lipid assemblies which can involve different processes, depending on experimental conditions: vesicularization of multibilayers; fusion of small lipid vesicles; fragmentation into discs and micelles. Such processes are discussed in connexion with the mechanism of action of melittin: the lysis of biological membranes and the synergism between melittin and phospholipases.

A restatement of melittin-induced effects on the thermotropism of zwitterionic phospholipids

Perturbations induced by melittin on the thermotropism of dimyristoyl-, dipalmitoyl-, distearoylphosphatidylcholine and natural sphingomyelin are investigated and rationalized from data obtained by fluorescence polarization, differential scanning calorimetry and Raman spectroscopy. Depending on the technique and/or experimental conditions used, the observed effects differ at the same lipid to protein molar ratio, due to partial binding of melittin. The binding is more efficient for tetrameric than for monomeric melittin, but in both cases its affinity is weaker for phosphatidylcholine dispersions in the gel phase than for sonicated vesicles. For temperatures T greater than or equal to Tm efficient binding occurs whatever the initial state of the lipids is. One can summarize the effects induced by melittin on the transition temperature as follows: No upward shift is observed on synthetic phosphatidylcholines when lipid degradation is avoided. This is achieved by using highly purified melittin, phospholipase inhibitors, and/or non-hydrolysable lipids. Melittin monomer does not change Tm. When melittin tetramer is stabilized, it decreases Tm by 10-15 deg. C. The transition broadens, and is finally abolished for Ri less than or equal to 2. Very similar results are found for natural sphingomyelin. Fluorescence polarization indicates similar changes in order and dynamics of the acyl chains for all lipid studied. For T less than or equal to Tm, fluorescence and Raman show that melittin decreases the amount of CH2 groups in 'trans' conformation and the intermolecular order of the chains. According to fluorescence data, there is an increase of the rigid-body orientational order at T greater than or equal to Tm, while from Raman the positional intermolecular order decreases without significant change in the CH2 groups 'trans'/'gauche' ratio.