Evacetrapib and Cardiovascular Outcomes in High-Risk Vascular Disease.

BACKGROUND: The cholesteryl ester transfer protein inhibitor evacetrapib substantially raises the high-density lipoprotein (HDL) cholesterol level, reduces the low-density lipoprotein (LDL) cholesterol level, and enhances cellular cholesterol efflux capacity. We sought to determine the effect of evacetrapib on major adverse cardiovascular outcomes in patients with high-risk vascular disease. METHODS: In a multicenter, randomized, double-blind, placebo-controlled phase 3 trial, we enrolled 12,092 patients who had at least one of the following conditions: an acute coronary syndrome within the previous 30 to 365 days, cerebrovascular atherosclerotic disease, peripheral vascular arterial disease, or diabetes mellitus with coronary artery disease. Patients were randomly assigned to receive either evacetrapib at a dose of 130 mg or matching placebo, administered daily, in addition to standard medical therapy. The primary efficacy end point was the first occurrence of any component of the composite of death from cardiovascular causes, myocardial infarction, stroke, coronary revascularization, or hospitalization for unstable angina. RESULTS: At 3 months, a 31.1% decrease in the mean LDL cholesterol level was observed with evacetrapib versus a 6.0% increase with placebo, and a 133.2% increase in the mean HDL cholesterol level was seen with evacetrapib versus a 1.6% increase with placebo. After 1363 of the planned 1670 primary end-point events had occurred, the data and safety monitoring board recommended that the trial be terminated early because of a lack of efficacy. After a median of 26 months of evacetrapib or placebo, a primary end-point event occurred in 12.9% of the patients in the evacetrapib group and in 12.8% of those in the placebo group (hazard ratio, 1.01; 95% confidence interval, 0.91 to 1.11; P=0.91). CONCLUSIONS: Although the cholesteryl ester transfer protein inhibitor evacetrapib had favorable effects on established lipid biomarkers, treatment with evacetrapib did not result in a lower rate of cardiovascular events than placebo among patients with high-risk vascular disease. (Funded by Eli Lilly; ACCELERATE ClinicalTrials.gov number, NCT01687998 .).

Association of high-density lipoprotein particle concentration with cardiovascular risk following acute coronary syndrome: A case-cohort analysis of the dal-Outcomes trial.

BACKGROUND: High-density lipoprotein cholesterol (HDL-C) concentration is inversely related to risk of major adverse cardiovascular events (MACE) in epidemiologic studies but is a poorer predictor of MACE in patients with established coronary heart disease. HDL particle concentration (HDLP) has been proposed as a better predictor of risk. We investigated whether HDLP is associated with risk of MACE after acute coronary syndrome (ACS). METHODS: The dal-Outcomes trial compared the CETP inhibitor dalcetrapib with placebo in patients with recent ACS. In a nested case-cohort analysis, total, large, medium, and small HDLPs were measured by nuclear magnetic resonance spectroscopy at baseline (4-12 weeks after ACS) in 476 cases with MACE and 902 controls. Hazard ratios (HRs; case-control) for 1-SD increment of HDLP or HDL-C at baseline were calculated with and without adjustment for demographic, clinical, laboratory, and treatment variables. Similarly, HRs for MACE were calculated for changes in HDLP or HDL-C from baseline to month 3 of assigned treatment. RESULTS: Over median follow-up of 28 months, the risk of MACE was not associated with baseline HDLP (adjusted HR = 0.98, 95% CI = 0.84-1.15, P = .81), any HDLP subclass, or HDL-C. Dalcetrapib increased HDL-C and total, medium, and large HDLP and decreased small HDLP but had no effect on MACE compared with placebo. There were no association of risk of MACE with change in HDLP or HDL-C and no interaction with assigned study treatment. CONCLUSIONS: Neither baseline HDLP nor the change in HDLP on treatment with dalcetrapib or placebo was associated with risk of MACE after ACS.

Apolipoprotein A-I improves pancreatic ß-cell function independent of the ATP-binding cassette transporters ABCA1 and ABCG1.

Apolipoprotein A-I (apoA-I), the main protein constituent of HDLs, increases insulin synthesis and insulin secretion in pancreatic ß cells. ApoA-I also accepts cholesterol that effluxes from cells expressing ATP-binding cassette transporter A1 (ABCA1) and ATP-binding cassette transporter G1 (ABCG1). Mice with conditional deletion of ABCA1 and ABCG1 in ß cells [ß-double knockout (DKO) mice] have increased islet cholesterol levels and reduced glucose-stimulated insulin secretion (GSIS). The project asks whether metabolic pathways are dysregulated in ß-DKO mouse islets and whether this can be corrected, and GSIS improved, by treatment with apoA-I. ß-DKO mice were treated with apoA-I or PBS, and islets were isolated for determination of GSIS. Total RNA was extracted from ß-DKO and control mouse islets for microarray analysis. Metabolic pathways were interrogated by functional enrichment analysis. ApoA-I treatment improved GSIS in ß-DKO but not control mouse islets. Plasma lipid and lipoprotein levels and islet cholesterol levels were also unaffected by treatment with apoA-I. Cholesterol metabolism, glucose metabolism, and inflammation pathways were dysregulated in ß-DKO mouse islets. This was not corrected by treatment with apoA-I. In summary, apoA-I treatment improves GSIS by a cholesterol-independent mechanism, but it does not correct metabolic dysregulation in ß-DKO mouse islets.-Hou, L., Tang, S., Wu, B. J., Ong, K.-L., Westerterp, M., Barter, P. J., Cochran, B. J., Tabet, F., Rye, K.-A. Apolipoprotein A-I improves pancreatic ß-cell function independent of the ATP-binding cassette transporters ABCA1 and ABCG1.

Apolipoprotein A-I Protects Against Pregnancy-Induced Insulin Resistance in Rats.

Objective- Insulin resistance and inflammation in pregnancy are risk factors for gestational diabetes mellitus. Increased plasma HDL (high-density lipoprotein) and apo (apolipoprotein) A-I levels have been reported to improve glucose metabolism and inhibit inflammation in animals and humans. This study asks whether increasing plasma apoA-I levels improves insulin sensitivity and reduces inflammation in insulin-resistant pregnant rats. Approach and Results- Insulin-resistant pregnant rats received intravenous infusions of lipid-free apoA-I (8 mg/kg) or saline on days 6, 9, 12, 15, and 18 of pregnancy. The rats were then subjected to a euglycemic-hyperinsulinemic clamp. Glucose uptake was increased in white and brown adipose tissue by 57±13% and 32±10%, respectively ( P<0.05 for both), and in quadriceps and gastrocnemius muscle by 35±9.7% and 47±14%, respectively ( P<0.05 for both), in the apoA-I-treated pregnant rats relative to saline-infused pregnant rats. The pregnant rats that were treated with apoA-I also had reduced plasma TNF-α (tumor necrosis factor-α) levels by 57±8.4%, plasma IL (interleukin)-6 levels by 67±9.5%, and adipose tissue macrophage content by 54±8.2% ( P<0.05 for all) relative to the saline-treated pregnant rats. Conclusions- These studies establish that apoA-I protects against pregnancy-induced insulin resistance in rats by increasing insulin sensitivity in adipose tissue and skeletal muscle and inhibiting inflammation. This identifies apoA-I as a potential target for preventing pregnancy-induced insulin resistance and reducing the incidence of gestational diabetes mellitus.

Gaps in beliefs and practice in dyslipidaemia management in Japan, Germany, Colombia and the Philippines: insights from a web-based physician survey.

BACKGROUND: Implementing evidence-based management of dyslipidaemia is a challenge worldwide. OBJECTIVES: To understand physician beliefs and behaviour and identify uncertainties in dyslipidaemia management across four world regions. METHODS: Web-based survey of 1758 physicians in Japan, Germany, Colombia and the Philippines who were selected randomly from existing databases. Key inclusion criteria were 1) for cardiologists and diabetes/endocrinology specialists: ≥50 dyslipidaemia patients examined in the last month; 2) for specialists in neurology/neurosurgery/stroke medicine: ≥50 dyslipidaemia patients and ≥ 20 patients with a history of ischaemic stroke examined in the last month; and 3) for specialists in nephrology and general medicine: based at centres with ≥20 beds and ≥ 50 dyslipidaemia patients examined in the last month. The self-report survey covered dyslipidaemia management, target low-density lipoprotein cholesterol (LDL-C) levels in different patient groups, and statin safety. All physicians gave voluntary consent and all data were anonymised. Analysis was solely descriptive. RESULTS: The survey highlighted key areas of uncertainty in dyslipidaemia management in the four countries. These related to LDL-C targets in different patient groups, the safety of low LDL-C levels, the safety of statins, especially for effects on cognitive, renal and hepatic function and for haemorrhagic stroke risk, and lipid management strategies in patients with chronic kidney disease, including those with concomitant hypertriglyceridaemia. CONCLUSIONS: This survey of physicians in Japan, Germany, Colombia and the Philippines has identified key gaps in knowledge about dyslipidaemia management. These relate to the safety of low LDL-C levels, the safety of statins, and lipid management of chronic kidney disease. The findings from this survey highlight the need for further education to improve the implementation of guideline recommendations for dyslipidaemia management.

Effect of High-Dose Omega-3 Fatty Acids vs Corn Oil on Major Adverse Cardiovascular Events in Patients at High Cardiovascular Risk: The STRENGTH Randomized Clinical Trial.

Importance: It remains uncertain whether the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) reduce cardiovascular risk. Objective: To determine the effects on cardiovascular outcomes of a carboxylic acid formulation of EPA and DHA (omega-3 CA) with documented favorable effects on lipid and inflammatory markers in patients with atherogenic dyslipidemia and high cardiovascular risk. Design, Setting, and Participants: A double-blind, randomized, multicenter trial (enrollment October 30, 2014, to June 14, 2017; study termination January 8, 2020; last patient visit May 14, 2020) comparing omega-3 CA with corn oil in statin-treated participants with high cardiovascular risk, hypertriglyceridemia, and low levels of high-density lipoprotein cholesterol (HDL-C). A total of 13 078 patients were randomized at 675 academic and community hospitals in 22 countries in North America, Europe, South America, Asia, Australia, New Zealand, and South Africa. Interventions: Participants were randomized to receive 4 g/d of omega-3 CA (n = 6539) or corn oil, which was intended to serve as an inert comparator (n = 6539), in addition to usual background therapies, including statins. Main Outcomes and Measures: The primary efficacy measure was a composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, coronary revascularization, or unstable angina requiring hospitalization. Results: When 1384 patients had experienced a primary end point event (of a planned 1600 events), the trial was prematurely halted based on an interim analysis that indicated a low probability of clinical benefit of omega-3 CA vs the corn oil comparator. Among the 13 078 treated patients (mean [SD] age, 62.5 [9.0] years; 35% women; 70% with diabetes; median low-density lipoprotein [LDL] cholesterol level, 75.0 mg/dL; median triglycerides level, 240 mg/dL; median HDL-C level, 36 mg/dL; and median high-sensitivity C-reactive protein level, 2.1 mg/L), 12 633 (96.6%) completed the trial with ascertainment of primary end point status. The primary end point occurred in 785 patients (12.0%) treated with omega-3 CA vs 795 (12.2%) treated with corn oil (hazard ratio, 0.99 [95% CI, 0.90-1.09]; P = .84). A greater rate of gastrointestinal adverse events was observed in the omega-3 CA group (24.7%) compared with corn oil-treated patients (14.7%). Conclusions and Relevance: Among statin-treated patients at high cardiovascular risk, the addition of omega-3 CA, compared with corn oil, to usual background therapies resulted in no significant difference in a composite outcome of major adverse cardiovascular events. These findings do not support use of this omega-3 fatty acid formulation to reduce major adverse cardiovascular events in high-risk patients. Trial Registration: ClinicalTrials.gov Identifier: NCT02104817.

The selective peroxisome proliferator-activated receptor alpha modulator (SPPARMα) paradigm: conceptual framework and therapeutic potential : A consensus statement from the International Atherosclerosis Society (IAS) and the Residual Risk Reduction Initiative (R3i) Foundation.

In the era of precision medicine, treatments that target specific modifiable characteristics of high-risk patients have the potential to lower further the residual risk of atherosclerotic cardiovascular events. Correction of atherogenic dyslipidemia, however, remains a major unmet clinical need. Elevated plasma triglycerides, with or without low levels of high-density lipoprotein cholesterol (HDL-C), offer a key modifiable component of this common dyslipidemia, especially in insulin resistant conditions such as type 2 diabetes mellitus. The development of selective peroxisome proliferator-activated receptor alpha modulators (SPPARMα) offers an approach to address this treatment gap. This Joint Consensus Panel appraised evidence for the first SPPARMα agonist and concluded that this agent represents a novel therapeutic class, distinct from fibrates, based on pharmacological activity, and, importantly, a safe hepatic and renal profile. The ongoing PROMINENT cardiovascular outcomes trial is testing in 10,000 patients with type 2 diabetes mellitus, elevated triglycerides, and low levels of HDL-C whether treatment with this SPPARMα agonist safely reduces residual cardiovascular risk.

Altered HDL metabolism in metabolic disorders: insights into the therapeutic potential of HDL.

Metabolic disorders are associated with an increased risk of cardiovascular disease (CVD), and are commonly characterized by a low plasma level of high-density lipoprotein cholesterol (HDL-C). Although cholesterol lowering medications reduce CVD risk in these patients, they often remain at increased risk of CVD. Therapeutic strategies that raise HDL-C levels and improve HDL function are a potential treatment option for reducing residual CVD risk in these individuals. Over the past decade, understanding of the metabolism and cardioprotective functions of HDLs has improved, with preclinical and clinical studies both indicating that the ability of HDLs to mediate reverse cholesterol transport, inhibit inflammation and reduce oxidation is impaired in metabolic disorders. These cardioprotective effects of HDLs are supported by the outcomes of epidemiological, cell and animal studies, but have not been confirmed in several recent clinical outcome trials of HDL-raising agents. Recent studies suggest that HDL function may be clinically more important than plasma levels of HDL-C. However, at least some of the cardioprotective functions of HDLs are lost in acute coronary syndrome and stable coronary artery disease patients. HDL dysfunction is also associated with metabolic abnormalities. This review is concerned with the impact of metabolic abnormalities, including dyslipidemia, obesity and Type 2 diabetes, on the metabolism and cardioprotective functions of HDLs.

New Era of Lipid-Lowering Drugs.

There are several established lipid-modifying agents, including statins, fibrates, niacin, and ezetimibe, that have been shown in randomized clinical outcome trials to reduce the risk of having an atherosclerotic cardiovascular event. However, in many people, the risk of having an event remains unacceptably high despite treatment with these established agents. This has stimulated the search for new therapies designed to reduce residual cardiovascular risk. New approaches that target atherogenic lipoproteins include: 1) inhibition of proprotein convertase subtilisin/kexin type 9 to increase removal of atherogenic lipoproteins from plasma; 2) inhibition of the synthesis of apolipoprotein (apo) B, the main protein component of atherogenic lipoproteins; 3) inhibition of microsomal triglyceride transfer protein to block the formation of atherogenic lipoproteins; 4) inhibition of adenosine triphosphate citrate lyase to inhibit the synthesis of cholesterol; 5) inhibition of the synthesis of lipoprotein(a), a factor known to cause atherosclerosis; 6) inhibition of apoC-III to reduce triglyceride-rich lipoproteins and to enhance high-density lipoprotein (HDL) functionality; and 7) inhibition of cholesteryl ester transfer protein, which not only reduces the concentration of atherogenic lipoproteins but also increases the level and function of the potentially antiatherogenic HDL fraction. Other new therapies that specifically target HDLs include infusions of reconstituted HDLs, HDL delipidation, and infusions of apoA-I mimetic peptides that mimic some of the functions of HDLs. This review describes the scientific basis and rationale for developing these new therapies and provides a brief summary of established therapies.

Status of PCSK9 Monoclonal Antibodies in Australia.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibodies (mAb) have progressed from showing marked low density lipoprotein cholesterol lowering in early phase trials through to reducing cardiovascular events in large clinical outcome trials. Recently in Australia, the indication for evolocumab has been expanded to include both heterozygous and homozygous familial hypercholesterolaemia under the Pharmaceutical Benefits Scheme (PBS). With prices remaining high currently their use in non-familial hypercholesterolaemia in Australia remains by private prescription only at this stage. This manuscript summarises the major outcomes trials of the PCSK9 mAbs and the secondary analyses that have assessed their benefits in high risk patient groups, and describes the consensus of authors on which patients would most likely benefit from PCSK9 mAb therapy.

Cholesteryl ester transfer protein and its inhibitors.

Most of the cholesterol in plasma is in an esterified form that is generated in potentially cardioprotective HDLs. Cholesteryl ester transfer protein (CETP) mediates bidirectional transfers of cholesteryl esters (CEs) and triglycerides (TGs) between plasma lipoproteins. Because CE originates in HDLs and TG enters the plasma as a component of VLDLs, activity of CETP results in a net mass transfer of CE from HDLs to VLDLs and LDLs, and of TG from VLDLs to LDLs and HDLs. As inhibition of CETP activity increases the concentration of HDL-cholesterol and decreases the concentration of VLDL- and LDL-cholesterol, it has the potential to reduce atherosclerotic CVD. This has led to the development of anti-CETP neutralizing monoclonal antibodies, vaccines, and antisense oligonucleotides. Small molecule inhibitors of CETP have also been developed and four of them have been studied in large scale cardiovascular clinical outcome trials. This review describes the structure of CETP and its mechanism of action. Details of its regulation and nonlipid transporting functions are discussed, and the results of the large scale clinical outcome trials of small molecule CETP inhibitors are summarized.

Reduction of In-Stent Restenosis by Cholesteryl Ester Transfer Protein Inhibition.

OBJECTIVE: Angioplasty and stent implantation, the most common treatment for atherosclerotic lesions, have a significant failure rate because of restenosis. This study asks whether increasing plasma high-density lipoprotein (HDL) levels by inhibiting cholesteryl ester transfer protein activity with the anacetrapib analog, des-fluoro-anacetrapib, prevents stent-induced neointimal hyperplasia. APPROACH AND RESULTS: New Zealand White rabbits received normal chow or chow supplemented with 0.14% (wt/wt) des-fluoro-anacetrapib for 6 weeks. Iliac artery endothelial denudation and bare metal steel stent deployment were performed after 2 weeks of des-fluoro-anacetrapib treatment. The animals were euthanized 4 weeks poststent deployment. Relative to control, dietary supplementation with des-fluoro-anacetrapib reduced plasma cholesteryl ester transfer protein activity and increased plasma apolipoprotein A-I and HDL cholesterol levels by 53±6.3% and 120±19%, respectively. Non-HDL cholesterol levels were unaffected. Des-fluoro-anacetrapib treatment reduced the intimal area of the stented arteries by 43±5.6% (P<0.001), the media area was unchanged, and the arterial lumen area increased by 12±2.4% (P<0.05). Des-fluoro-anacetrapib treatment inhibited vascular smooth muscle cell proliferation by 41±4.5% (P<0.001). Incubation of isolated HDLs from des-fluoro-anacetrapib-treated animals with human aortic smooth muscle cells at apolipoprotein A-I concentrations comparable to their plasma levels inhibited cell proliferation and migration. These effects were dependent on scavenger receptor-B1, the adaptor protein PDZ domain-containing protein 1, and phosphatidylinositol-3-kinase/Akt activation. HDLs from des-fluoro-anacetrapib-treated animals also inhibited proinflammatory cytokine-induced human aortic smooth muscle cell proliferation and stent-induced vascular inflammation. CONCLUSIONS: Inhibiting cholesteryl ester transfer protein activity in New Zealand White rabbits with iliac artery balloon injury and stent deployment increases HDL levels, inhibits vascular smooth muscle cell proliferation, and reduces neointimal hyperplasia in an scavenger receptor-B1, PDZ domain-containing protein 1- and phosphatidylinositol-3-kinase/Akt-dependent manner.

Modeling Statin-Induced Reductions of Cardiovascular Events in Primary Prevention: A VOYAGER Meta-Analysis.

OBJECTIVE: We used individual patient data from the VOYAGER database to estimate cardiovascular (CV) risk reduction with commonly used high-intensity statins. METHODS: In patients with known atherosclerotic CV disease (ASCVD) treated with high-intensity statin therapy (n = 6,735), the predicted risk reduction was estimated using the Cholesterol Treatment Trialists' Collaboration meta-analysis, which determined risk reduction per 38.7 mg/dL statin-mediated reduction in low-density lipoprotein cholesterol. RESULTS: The greatest reductions in risk were seen in major vascular events (estimated rate ratios ranged from 0.55 with rosuvastatin [RSV] 40 mg to 0.60 with atorvastatin [ATV] 40 mg) and coronary heart disease death (estimated rate ratios ranged from 0.58 with RSV 40 mg to 0.64 with ATV 40 mg). CONCLUSIONS: Our results show that, in individuals without clinical ASCVD, statin therapy has the potential to reduce the frequency of CV events.

Baseline Circulating FGF21 Concentrations and Increase after Fenofibrate Treatment Predict More Rapid Glycemic Progression in Type 2 Diabetes: Results from the FIELD Study.

BACKGROUND: It is not known whether circulating fibroblast growth factor 21 (FGF21) concentrations are associated with glycemic progression in patients with established type 2 diabetes. This study reports this relationship in type 2 diabetes patients participating in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial. METHODS: Plasma FGF21 was quantified in 9697 study participants. Among patients with lifestyle-only glucose control measures at baseline, glycemic progression was defined as the initiation of oral hypoglycemic agents or insulin therapy. We assessed the relationship of FGF21 concentrations with glycohemoglobin (Hb A1c), the homeostasis model assessment of ß-cell function (HOMA-B) and insulin resistance (HOMA-IR), and glycemic progression. RESULTS: Among 2584 patients with lifestyle-only glycemic therapy at baseline, plasma FGF21 concentrations were positively associated with HOMA-IR (5.1% increase per 100% increase in FGF21 concentrations). Patients with higher baseline plasma FGF21 concentrations had higher risk of glycemic progression over a 5-year period (P = 0.02), but the association was not significant after further adjusting for alanine aminotransferase (ALT) enzyme activity. During the fenofibrate active run-in phase, higher tertiles of fenofibrate-induced increase in FGF21 concentrations were associated with higher risk of glycemic progression (adjusted hazards ratio = 1.09 and 1.18 for tertiles 2 and 3, respectively, P for trend = 0.01), even after adjusting for ALT enzyme activity. This association was statistically significant in the fenofibrate group only (P = 0.01). CONCLUSIONS: Higher baseline and fenofibrate-induced increase in FGF21 concentrations predict more rapid glycemic progression in type 2 diabetes patients. This association may be partly explained by hepatic function.

Inhibition of inflammatory signaling pathways in 3T3-L1 adipocytes by apolipoprotein A-I.

Activation of inflammatory signaling pathways links obesity with metabolic disorders. TLR4-mediated activation of MAPKs and NF-κB are 2 such pathways implicated in obesity-induced inflammation. Apolipoprotein A-I (apoA-I) exerts anti-inflammatory effects on adipocytes by effluxing cholesterol from the cells via the ATP binding cassette transporter A1 (ABCA1). It is not known if these effects involve inhibition of inflammatory signaling pathways by apoA-I. This study asks if apoA-I inhibits activation of MAPKs and NF-κB in mouse 3T3-L1 adipocytes and whether this inhibition is ABCA1 dependent. Incubation of differentiated 3T3-L1 adipocytes with apoA-I decreased cell surface expression of TLR4 by 16 ± 2% and synthesis of the TLR4 adaptor protein, myeloid differentiation primary response 88, by 24 ± 4% in an ABCA1-dependent manner. ApoA-I also inhibited downstream activation of MAPKs, such as ERK, p38MAPK, and JNK, as well as expression of proinflammatory adipokines in bacterial LPS-stimulated 3T3-L1 adipocytes in an ABCA1-dependent manner. ApoA-I, by contrast, suppressed nuclear localization of the p65 subunit of NF-κB by 30 ± 3% in LPS-stimulated 3T3-L1 adipocytes in an ABCA1-independent manner. In conclusion, apoA-I inhibits TLR4-mediated inflammatory signaling pathways in adipocytes by preventing MAPK and NF-κB activation.-Sultana, A., Cochran, B. J., Tabet, F., Patel, M., Cuesta Torres, L., Barter, P. J., Rye, K.-A. Inhibition of inflammatory signaling pathways in 3T3-L1 adipocytes by apolipoprotein A-I.

Cholesteryl Ester Transfer Protein Inhibition Is Not Yet Dead--Pro.

Cholesteryl ester transfer protein (CETP) transfers cholesteryl esters from nonatherogenic high-density lipoproteins to potentially proatherogenic non-high-density lipoprotein fractions. Human genetic studies and human cohort studies have concluded that CETP gene polymorphisms associated with decreased CETP activity are accompanied by a significantly lower risk of atherosclerotic cardiovascular disease. Inhibition of CETP in rabbits reduces development of diet-induced atherosclerosis. Inhibition of CETP in humans reduces non-high-density lipoprotein cholesterol while increasing high-density lipoproteins cholesterol, consistent with a reduced risk of having an atherosclerotic cardiovascular disease event. The failure of randomized human clinical outcome trials with 3 different CETP inhibitors may have been the consequence of either off-target adverse effects of the drug used or problems with the design of the trials. The hypothesis that CETP inhibition reduces atherosclerotic cardiovascular disease risk is still untested. The future of CETP inhibition as a cardio-protective strategy will depend on the outcome of the ongoing Randomized Evaluation of the Effects of Anacetrapib Through Lipid-Modification (REVEAL) trial with the CETP inhibitor, anacetrapib.

Apolipoprotein A-I interactions with insulin secretion and production.

PURPOSE OF REVIEW: Human population studies have established that an elevated plasma high-density lipoprotein cholesterol (HDL-C) level is associated with a decreased risk of developing cardiovascular disease. In addition to having several potentially cardioprotective functions, HDLs and apolipoprotein (apo)A-I, the main HDL apolipoprotein, also have antidiabetic properties. Interventions that elevate plasma HDL-C and apoA-I levels improve glycemic control in people with type 2 diabetes mellitus by enhancing pancreatic ß-cell function and increasing insulin sensitivity. RECENT FINDINGS: This review is concerned with recent advances in understanding the mechanisms by which HDLs and apoA-I improve pancreatic ß-cell function. SUMMARY: HDLs and apoA-I increase insulin synthesis and secretion in pancreatic ß cells. The underlying mechanism of this effect is similar to what has been reported for intestinally derived incretins, such as glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide, which both increase ß-cell insulin secretion under high glucose conditions. This involves the activation of a heterotrimeric G protein Gαs subunit on the ß-cell surface that leads to induction of a transmembrane adenylyl cyclase, increased intracellular cyclic adenosine monophosphate and Ca levels, and activation of protein kinase A. Protein kinase A increases insulin synthesis by excluding FoxO1 from the ß-cell nucleus and derepressing transcription of the insulin gene.

In vivo PET imaging with [(18)F]FDG to explain improved glucose uptake in an apolipoprotein A-I treated mouse model of diabetes.

AIMS/HYPOTHESIS: Type 2 diabetes is characterised by decreased HDL levels, as well as the level of apolipoprotein A-I (apoA-I), the main apolipoprotein of HDLs. Pharmacological elevation of HDL and apoA-I levels is associated with improved glycaemic control in patients with type 2 diabetes. This is partly due to improved glucose uptake in skeletal muscle. METHODS: This study used kinetic modelling to investigate the impact of increasing plasma apoA-I levels on the metabolism of glucose in the db/db mouse model. RESULTS: Treatment of db/db mice with apoA-I for 2 h significantly improved both glucose tolerance (AUC 2574 ± 70 mmol/l × min vs 2927 ± 137 mmol/l × min, for apoA-I and PBS, respectively; p < 0.05) and insulin sensitivity (AUC 388.8 ± 23.8 mmol/l × min vs 194.1 ± 19.6 mmol/l × min, for apoA-I and PBS, respectively; p < 0.001). ApoA-I treatment also increased glucose uptake by skeletal muscle in both an insulin-dependent and insulin-independent manner as evidenced by increased uptake of fludeoxyglucose ([(18)F]FDG) from plasma into gastrocnemius muscle in apoA-I treated mice, both in the absence and presence of insulin. Kinetic modelling revealed an enhanced rate of insulin-mediated glucose phosphorylation (k 3) in apoA-I treated mice (3.5 ± 1.1 × 10(-2) min(-1) vs 2.3 ± 0.7 × 10(-2) min(-1), for apoA-I and PBS, respectively; p < 0.05) and an increased influx constant (3.7 ± 0.6 × 10(-3) ml min(-1) g(-1) vs 2.0 ± 0.3 × 10(-3) ml min(-1) g(-1), for apoA-I and PBS, respectively; p < 0.05). Treatment of L6 rat skeletal muscle cells with apoA-I for 2 h indicated that increased hexokinase activity mediated the increased rate of glucose phosphorylation. CONCLUSIONS/INTERPRETATION: These findings indicate that apoA-I improves glucose disposal in db/db mice by improving insulin sensitivity and enhancing glucose phosphorylation.

Cholesterol ester transfer protein inhibition by TA-8995 in patients with mild dyslipidaemia (TULIP): a randomised, double-blind, placebo-controlled phase 2 trial.

BACKGROUND: Dyslipidaemia remains a significant risk factor for cardiovascular disease and additional lipid-modifying treatments are warranted to further decrease the cardiovascular disease burden. We assessed the safety, tolerability and efficacy of a novel cholesterol esterase transfer protein (CETP) inhibitor TA-8995 in patients with mild dyslipidaemia. METHODS: In this randomised, double-blind, placebo-controlled, parallel-group phase 2 trial, we recruited patients (aged 18-75 years) from 17 sites (hospitals and independent clinical research organisations) in the Netherlands and Denmark with fasting LDL cholesterol levels between 2·5 mmol/L and 4·5 mmol/L, HDL cholesterol levels between 0·8 and 1·8 mmol/L and triglyceride levels below 4·5 mmol/L after washout of lipid-lowering treatments. Patients were randomly allocated (1:1) by a computer-generated randomisation schedule to receive one of the following nine treatments: a once a day dose of 1 mg, 2·5 mg, 5 mg, or 10 mg TA-8995 or matching placebo; 10 mg TA-8995 plus 20 mg atorvastatin; 10 mg TA-8995 plus 10 mg rosuvastatin or 20 mg atorvastatin or 10 mg rosuvastatin alone. We overencapsulated statins to achieve masking. The primary outcome was percentage change in LDL cholesterol and HDL cholesterol from baseline at week 12, analysed by intention to treat. This study is registered with ClinicalTrials.gov, number NCT01970215. FINDINGS: Between Aug 15, 2013, and Jan 10, 2014, 364 patients were enrolled. At week 12, LDL cholesterol levels were reduced by 27·4% in patients assigned to the 1 mg dose, 32·7% in patients given the 2·5 mg dose, 45·3% in those given the 5 mg dose, and 45·3% in those given the 10 mg dose (p<0·0001). LDL cholesterol levels were reduced by 68·2% in patients given 10 mg TA-8995 plus atorvastatin, and by 63·3% in patients given rosuvastatin plus 10 mg TA-8995 (p<0·0001). A daily dose of 1 mg TA-8995 increased HDL cholesterol levels by 75·8%, 2·5 mg by 124·3%, 5 mg by 157·1%, and 10 mg dose by 179·0% (p<0·0001). In patients receiving 10 mg TA-8995 and 20 mg atorvastatin HDL cholesterol levels increased by 152·1% and in patients receiving 10 mg TA-8995 and 10 mg rosuvastatin by 157·5%. We recorded no serious adverse events or signs of liver or muscle toxic effects. INTERPRETATION: TA-8995, a novel CETP inhibitor, is well tolerated and has beneficial effects on lipids and apolipoproteins in patients with mild dyslipidaemia. A cardiovascular disease outcome trial is needed to translate these effects into a reduction of cardiovascular disease events. FUNDING: Dezima.

Regulation of high-density lipoprotein metabolism.

There is compelling evidence from human population studies that plasma levels of high-density lipoprotein (HDL) cholesterol correlate inversely with cardiovascular risk. Identification of this relationship has stimulated research designed to understand how HDL metabolism is regulated. The ultimate goal of these studies has been to develop HDL-raising therapies that have the potential to decrease the morbidity and mortality associated with atherosclerotic cardiovascular disease. However, the situation has turned out to be much more complex than originally envisaged. This is partly because the HDL fraction consists of multiple subpopulations of particles that vary in terms of shape, size, composition, and surface charge, as well as in their potential cardioprotective properties. This heterogeneity is a consequence of the continual remodeling and interconversion of HDL subpopulations by multiple plasma factors. Evidence that the remodeling of HDLs may impact on their cardioprotective properties is beginning to emerge. This serves to highlight the importance of understanding not only how the remodeling and interconversion of HDL subpopulations is regulated but also how these processes are affected by agents that increase HDL levels. This review provides an overview of what is currently understood about HDL metabolism and how the subpopulation distribution of these lipoproteins is regulated.