Therapy with cholesteryl ester transfer protein (CETP) inhibitors and diabetes risk

Obicetrapib on top of maximally tolerated lipid-modifying therapies in participants with or at high risk for atherosclerotic cardiovascular disease: rationale and designs of BROADWAY and BROOKLYN

BACKGROUND

Obicetrapib, a novel, selective cholesteryl ester transfer protein (CETP) inhibitor, reduces low-density lipoprotein cholesterol (LDL-C), LDL particles, apolipoprotein (Apo) B, and lipoprotein(a) [Lp(a)] and increases high-density lipoprotein cholesterol (HDL-C) when added to statins with or without ezetimibe. By substantially reducing LDL-C, obicetrapib has the potential to lower atherogenic lipoproteins in patients with atherosclerotic cardiovascular disease (ASCVD) or heterozygous familial hypercholesterolemia (HeFH) whose LDL-C levels remain high despite treatment with available maximally tolerated lipid-modifying therapies, addressing an unmet medical need in a patient population at high risk for cardiovascular events.

METHODS AND RESULTS

BROADWAY (NCT05142722) and BROOKLYN (NCT05425745) are ongoing placebo-controlled, double-blind, randomized Phase III trials designed to examine the efficacy, safety, and tolerability of obicetrapib as an adjunct to dietary intervention and maximally tolerated lipid-modifying therapies in participants with a history of ASCVD and/or underlying HeFH whose LDL-C is not adequately controlled. The primary efficacy endpoint was the percent change in LDL-C from baseline to day 84. Other endpoints included changes in Apo B, non-HDL-C, HDL-C, Apo A1, Lp(a), and triglycerides in addition to parameters evaluating safety, tolerability, and pharmacokinetics. BROADWAY also included an adjudicated assessment of major adverse cardiovascular events, measurements of glucose homeostasis, and an ambulatory blood pressure monitoring substudy. A total of 2,532 participants were randomized in BROADWAY and 354 in BROOKLYN to receive obicetrapib 10 mg or placebo (2:1) for 365 days with follow-up through 35 days after the last dose. Results from both trials are anticipated in 2024.

CONCLUSION

These trials will provide safety and efficacy data to support the potential use of obicetrapib among patients with ASCVD or HeFH with elevated LDL-C for whom existing therapies are not sufficiently effective or well-tolerated.

CETP and SGLT2 inhibitor combination therapy increases glycemic control: a 2x2 factorial Mendelian randomization analysis

Introduction

Cholesteryl ester transfer protein (CETP) inhibitors, initially developed for treating hyperlipidemia, have shown promise in reducing the risk of new-onset diabetes during clinical trials. This positions CETP inhibitors as potential candidates for repurposing in metabolic disease treatment. Given their oral administration, they could complement existing oral medications like sodium-glucose cotransporter 2 (SGLT2) inhibitors, potentially delaying the need for injectable therapies such as insulin.

Methods

We conducted a 2x2 factorial Mendelian Randomization analysis involving 233,765 participants from the UK Biobank. This study aimed to evaluate whether simultaneous genetic inhibition of CETP and SGLT2 enhances glycemic control compared to inhibiting each separately.

Results

Our findings indicate that dual genetic inhibition of CETP and SGLT2 significantly reduces glycated hemoglobin levels compared to controls and single-agent inhibition. Additionally, the combined inhibition is linked to a lower incidence of diabetes compared to both the control group and SGLT2 inhibition alone.

Discussion

These results suggest that combining CETP and SGLT2 inhibitor therapies may offer superior glycemic control over SGLT2 inhibitors alone. Future clinical trials should investigate the potential of repurposing CETP inhibitors for metabolic disease treatment, providing an oral therapeutic option that could benefit high-risk patients before they require injectable therapies like insulin or glucagon-like peptide-1 (GLP-1) receptor agonists.

Hyperlipidaemia in diabetes: are there particular considerations for next-generation therapies?

Dyslipidaemias are major cardiovascular risk factors, especially in people with diabetes. In this area, next-generation therapies targeting circulating lipoparticle metabolism (LDL, VLDL, chylomicrons, HDL) have recently been approved by the European and US medical agencies, including anti- proprotein convertase subtilisin/kexin 9 (PCSK9) antibodies; an siRNA targeting PCSK9; bempedoic acid, which targets ATP citrate lyase; an antisense oligonucleotide targeting apolipoprotein C-III; an anti-angiopoietin-like 3 antibody; and a purified omega-3 fatty acid, icosapent ethyl. Other therapies are in different phases of development. There are several important considerations concerning the link between these new lipid-lowering therapies and diabetes. First, since concerns were first raised in 2008 about an increased risk of new-onset diabetes mellitus (NODM) with intensive statin treatment, each new lipid-lowering therapy is being evaluated for its associated risk of NODM, particularly in individuals with prediabetes (impaired fasting glucose and/or impaired glucose tolerance). Second, people with diabetes represent a large proportion of those at high or very high cardiovascular risk in whom these lipid-lowering drugs are currently, or will be, prescribed. Thus, the efficacy of these drugs in subgroups with diabetes should also be closely considered, as well as any potential effects on glycaemic control. In this review, we describe the efficacy of next-generation therapies targeting lipoprotein metabolism in subgroups of people with diabetes and their effects on glycaemic control in individuals with diabetes and prediabetes and in normoglycaemic individuals.

Association between high-density lipoprotein cholesterol and reversion to normoglycemia from prediabetes: an analysis based on data from a retrospective cohort study

The available evidence on the connection between high-density lipoprotein cholesterol (HDL-C) levels and the reversion from prediabetes (Pre-DM) to normoglycemia is currently limited. The present research sought to examine the connection between HDL-C levels and the regression from Pre-DM to normoglycemia in a population of Chinese adults. This historical cohort study collected 15,420 Pre-DM patients in China who underwent health screening between 2010 and 2016. The present research used the Cox proportional hazards regression model to investigate the connection between HDL-C levels and reversion from Pre-DM to normoglycemia. The Cox proportional hazards regression model with cubic spline functions and smooth curve fitting was employed to ascertain the nonlinear association between HDL-C and reversion from Pre-DM to normoglycemia. Furthermore, a set of sensitivity analyses and subgroup analyses were employed. Following the adjustment of covariates, the findings revealed a positive connection between HDL-C levels and the likelihood of reversion from Pre-DM to normoglycemia (HR 1.898, 95% CI 1.758-2.048, P < 0.001). Furthermore, there was a non-linear relationship between HDL-C and the reversion from Pre-DM to normoglycemia in both genders, and the inflection point of HDL-C was 1.540 mmol/L in males and 1.620 mmol/L in females. We found a strong positive correlation between HDL-C and the reversion from Pre-DM to normoglycemia on the left of the inflection point (Male: HR 2.783, 95% CI 2.373-3.263; Female: HR 2.217, 95% CI 1.802-2.727). Our sensitivity analysis confirmed the robustness of these findings. Subgroup analyses indicated that patients with SBP < 140 mmHg and ever smoker exhibited a more pronounced correlation between HDL-C levels and the reversion from Pre-DM to normoglycemia. In contrast, a less robust correlation was observed among patients with SBP ≥ 140 mmHg, current and never smokers. This study provides evidence of a positive and nonlinear association between HDL-C levels and the reversion from Pre-DM to normoglycemia in Chinese patients. Implementing intensified intervention measures to control the HDL-C levels of patients with Pre-DM around the inflection point may substantially enhance the likelihood of regression to normoglycemia.

Type 2 Diabetes and HDL Dysfunction: A Key Contributor to Glycemic Control

High-density lipoproteins (HDL) have been shown to exert multiple cardioprotective and antidiabetic functions, such as their ability to promote cellular cholesterol efflux and their antioxidant, anti-inflammatory, and antiapoptotic properties. Type 2 diabetes (T2D) is usually associated with low high-density lipoprotein cholesterol (HDL-C) levels as well as with significant alterations in the HDL composition, thereby impairing its main functions. HDL dysfunction also negatively impacts both pancreatic β-cell function and skeletal muscle insulin sensitivity, perpetuating this adverse self-feeding cycle. The impairment of these pathways is partly dependent on cellular ATP-binding cassette transporter (ABC) A1-mediated efflux to lipid-poor apolipoprotein (apo) A-I in the extracellular space. In line with these findings, experimental interventions aimed at improving HDL functions, such as infusions of synthetic HDL or lipid-poor apoA-I, significantly improved glycemic control in T2D patients and experimental models of the disease. Cholesteryl ester transfer protein (CETP) inhibitors are specific drugs designed to increase HDLC and HDL functions. Posthoc analyses of large clinical trials with CETP inhibitors have demonstrated their potential anti-diabetic properties. Research on HDL functionality and HDL-based therapies could be a crucial step toward improved glycemic control in T2D subjects.

The evolving role of cholesteryl ester transfer protein inhibition beyond cardiovascular disease

The main role of cholesteryl ester transfer protein (CETP) is the transfer of cholesteryl esters and triglycerides between high-density lipoprotein (HDL) particles and triglyceride-rich lipoprotein and low-density lipoprotein (LDL) particles. There is a long history of investigations regarding the inhibition of CETP as a target for reducing major adverse cardiovascular events. Initially, the potential effect on cardiovascular events of CETP inhibitors was hypothesized to be mediated by their ability to increase HDL cholesterol, but, based on evidence from anacetrapib and the newest CETP inhibitor, obicetrapib, it is now understood to be primarily due to reducing LDL cholesterol and apolipoprotein B. Nevertheless, evidence is also mounting that other roles of HDL, including its promotion of cholesterol efflux, as well as its apolipoprotein composition and anti-inflammatory, anti-oxidative, and anti-diabetic properties, may play important roles in several diseases beyond cardiovascular disease, including, but not limited to, Alzheimer's disease, diabetes, and sepsis. Furthermore, although Mendelian randomization analyses suggested that higher HDL cholesterol is associated with increased risk of age-related macular degeneration (AMD), excess risk of AMD was absent in all CETP inhibitor randomized controlled trial data comprising over 70,000 patients. In fact, certain HDL subclasses may, in contrast, be beneficial for treating the retinal cholesterol accumulation that occurs with AMD. This review describes the latest biological evidence regarding the relationship between HDL and CETP inhibition for Alzheimer's disease, type 2 diabetes mellitus, sepsis, and AMD.

Advances in Treatment of Dyslipidemia

Dyslipidemias have emerged as prevalent disorders among patients, posing significant risks for the development and progression of cardiovascular diseases. These conditions are characterized by elevated levels of total cholesterol (TC), triglycerides (TGs), and low-density lipoprotein cholesterol (LDL-C). This review delves into the current treatment approach, focusing on equalizing these parameters while enhancing the overall quality of life for patients. Through an extensive analysis of clinical trials, we identify disorders that necessitate alternative treatment strategies, notably familial hypercholesterolemia. The primary objective of this review is to consolidate existing information concerning drugs with the potential to revolutionize dyslipidemia management significantly. Among these promising pharmaceuticals, we highlight alirocumab, bempedoic acid, antisense oligonucleotides, angiopoietin-like protein inhibitors, apolipoprotein C-III (APOC3) inhibitors, lomitapide, and cholesterol ester transfer protein (CETP) inhibitors. Our review demonstrates the pivotal roles played by each of these drugs in targeting specific parameters of lipid metabolism. We outline the future landscape of dyslipidemia treatment, envisaging a more tailored and effective therapeutic approach to address this widespread medical concern.

CETP and SGLT2 inhibitor combination therapy improves glycemic control

Importance

Cholesteryl ester transfer protein (CETP) inhibition has been associated with decreased risk of new-onset diabetes in past clinical trials exploring their efficacy in cardiovascular disease and can potentially be repurposed to treat metabolic disease. Notably, as an oral drug it can potentially be used to supplement existing oral drugs such as sodium-glucose cotransporter 2 (SGLT2) inhibitors before patients are required to take injectable drugs such as insulin.

Objective

To identify whether CETP inhibitors could be used as an oral add-on to SGLT2 inhibition to improve glycemic control.

Design Setting and Participants

2×2 factorial Mendelian Randomization (MR) is performed on the general population of UK Biobank participants with European ancestry.

Exposures

Previously constructed genetic scores for CETP and SGLT2 function are combined in a 2×2 factorial framework to characterize the associations between joint CETP and SGLT2 inhibition compared to either alone.

Main Outcomes and Measures

Glycated hemoglobin and type-2 diabetes incidence.

Results

Data on 233,765 UK Biobank participants suggests that individuals with genetic inhibition of both CETP and SGLT2 have significantly lower glycated hemoglobin levels (mmol/mol) than control (Effect size: -0.136; 95% CI: -0.190 to -0.081; p-value: 1.09E-06), SGLT2 inhibition alone (Effect size: -0.082; 95% CI: -0.140 to -0.024; p-value: 0.00558), and CETP inhibition alone (Effect size: -0.08479; 95% CI: -0.136 to -0.033; p-value: 0.00118). Furthermore, joint CETP and SGLT2 inhibition is associated with decreased incidence of diabetes (log-odds ratio) compared to control (Effect size: -0.068; 95% CI: -0.115 to -0.021; p-value: 4.44E-03) and SGLT2 inhibition alone (Effect size: -0.062; 95% CI: -0.112 to -0.012; p-value: 0.0149).

Conclusions and Relevance

Our results suggest that CETP and SGLT2 inhibitor therapy may improve glycemic control over SGLT2 inhibitors alone. Future clinical trials can explore whether CETP inhibitors can be repurposed to treat metabolic disease and provide an oral therapeutic option to benefit high-risk patients before escalation to injectable drugs such as insulin or glucagon-like peptide 1 (GLP1) receptor agonists.

HDL Function and Atherosclerosis: Reactive Dicarbonyls as Promising Targets of Therapy

Epidemiologic studies detected an inverse relationship between HDL (high-density lipoprotein) cholesterol (HDL-C) levels and atherosclerotic cardiovascular disease (ASCVD), identifying HDL-C as a major risk factor for ASCVD and suggesting atheroprotective functions of HDL. However, the role of HDL-C as a mediator of risk for ASCVD has been called into question by the failure of HDL-C-raising drugs to reduce cardiovascular events in clinical trials. Progress in understanding the heterogeneous nature of HDL particles in terms of their protein, lipid, and small RNA composition has contributed to the realization that HDL-C levels do not necessarily reflect HDL function. The most examined atheroprotective function of HDL is reverse cholesterol transport, whereby HDL removes cholesterol from plaque macrophage foam cells and delivers it to the liver for processing and excretion into bile. Indeed, in several studies, HDL has shown inverse associations between HDL cholesterol efflux capacity and ASCVD in humans. Inflammation plays a key role in the pathogenesis of atherosclerosis and vulnerable plaque formation, and a fundamental function of HDL is suppression of inflammatory signaling in macrophages and other cells. Oxidation is also a critical process to ASCVD in promoting atherogenic oxidative modifications of LDL (low-density lipoprotein) and cellular inflammation. HDL and its proteins including apoAI (apolipoprotein AI) and PON1 (paraoxonase 1) prevent cellular oxidative stress and LDL modifications. Importantly, HDL in humans with ASCVD is oxidatively modified rendering HDL dysfunctional and proinflammatory. Modification of HDL with reactive carbonyl species, such as malondialdehyde and isolevuglandins, dramatically impairs the antiatherogenic functions of HDL. Importantly, treatment of murine models of atherosclerosis with scavengers of reactive dicarbonyls improves HDL function and reduces systemic inflammation, atherosclerosis development, and features of plaque instability. Here, we discuss the HDL antiatherogenic functions in relation to oxidative modifications and the potential of reactive dicarbonyl scavengers as a therapeutic approach for ASCVD.

High-density lipoprotein revisited: biological functions and clinical relevance

Previous interest in high-density lipoproteins (HDLs) focused on their possible protective role in atherosclerotic cardiovascular disease (ASCVD). Evidence from genetic studies and randomized trials, however, questioned that the inverse association of HDL-cholesterol (HDL-C) is causal. This review aims to provide an update on the role of HDL in health and disease, also beyond ASCVD. Through evolution from invertebrates, HDLs are the principal lipoproteins, while apolipoprotein B-containing lipoproteins first developed in vertebrates. HDLs transport cholesterol and other lipids between different cells like a reusable ferry, but serve many other functions including communication with cells and the inactivation of biohazards like bacterial lipopolysaccharides. These functions are exerted by entire HDL particles or distinct proteins or lipids carried by HDL rather than by its cholesterol cargo measured as HDL-C. Neither does HDL-C measurement reflect the efficiency of reverse cholesterol transport. Recent studies indicate that functional measures of HDL, notably cholesterol efflux capacity, numbers of HDL particles, or distinct HDL proteins are better predictors of ASCVD events than HDL-C. Low HDL-C levels are related observationally, but also genetically, to increased risks of infectious diseases, death during sepsis, diabetes mellitus, and chronic kidney disease. Additional, but only observational, data indicate associations of low HDL-C with various autoimmune diseases, and cancers, as well as all-cause mortality. Conversely, extremely high HDL-C levels are associated with an increased risk of age-related macular degeneration (also genetically), infectious disease, and all-cause mortality. HDL encompasses dynamic multimolecular and multifunctional lipoproteins that likely emerged during evolution to serve several physiological roles and prevent or heal pathologies beyond ASCVD. For any clinical exploitation of HDL, the indirect marker HDL-C must be replaced by direct biomarkers reflecting the causal role of HDL in the respective disease.

The effect of CETP inhibitors on new-onset diabetes: a systematic review and meta-analysis

BACKGROUND

Despite the increasing prevalence of type 2 diabetes mellitus (T2DM), limited pharmacologic options are available for prevention. Cholesteryl ester transfer protein inhibitors (CETPis) have been studied primarily as a therapy to reduce cardiovascular disease, but have also been shown to reduce new-onset diabetes. As new trial data have become available, this meta-analysis examines the effect of CETP inhibitors on new-onset diabetes and related glycaemic measures.

METHODS AND RESULTS

We searched MEDLINE, EMBASE, and Cochrane databases (all articles until 4 March, 2021) for randomised controlled trials (RCT) ≥1-year duration, with at least 500 participants, comparing CETPi to placebo, and that reported data on new-onset diabetes or related glycaemic measures [haemoglobin A1C (HbA1C), fasting plasma glucose, insulin, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR)]. A fixed effects meta-analysis model was applied to all eligible studies to quantify the effect of CETPi therapy on new-onset diabetes. Four RCTs (n = 75 102) were eligible for quantitative analysis of the effect of CETPi on new-onset diabetes. CETPis were found to significantly decrease the risk of new-onset diabetes by 16% (RR: 0.84; 95% CI: 0.78, 0.91; P < 0.001), with low between-trial heterogeneity (I2 = 4.1%). Glycaemic measures were also significantly improved or trended towards improvement in those with and without diabetes across most trials.

CONCLUSION

Although RCTs have shown mixed results regarding the impact of CETPi on cardiovascular disease, they have shown a consistent reduction in the risk of new-onset diabetes with CETPi therapy. Future trials of CETPis and potentially other HDL-raising agents should therefore specify new-onset diabetes and reversal of existing T2DM as secondary endpoints.

Circulating Metabolic Biomarkers Are Consistently Associated With Type 2 Diabetes Risk in Asian and European Populations

CONTEXT

While Asians have a higher risk of type 2 diabetes (T2D) than Europeans for a given body mass index (BMI), it remains unclear whether the same markers of metabolic pathways are associated with diabetes.

OBJECTIVE

We evaluated associations between metabolic biomarkers and incidence of T2D in 3 major Asian ethnic groups (Chinese, Malay, and Indian) and a European population.

METHODS

We analyzed data from adult males and females of 2 cohorts from Singapore (n = 6393) consisting of Chinese, Malays, and Indians and 3 cohorts of European-origin participants from Finland (n = 14 558). We used nuclear magnetic resonance to quantify 154 circulating metabolic biomarkers at baseline and performed logistic regression to assess associations with T2D risk adjusted for age, sex, BMI and glycemic markers.

RESULTS

Of the 154 metabolic biomarkers, 59 were associated with higher risk of T2D in both Asians and Europeans (P < 0.0003, Bonferroni-corrected). These included branched chain and aromatic amino acids, the inflammatory marker glycoprotein acetyls, total fatty acids, monounsaturated fatty acids, apolipoprotein B, larger very low-density lipoprotein particle sizes, and triglycerides. In addition, 13 metabolites were associated with a lower T2D risk in both populations, including omega-6 polyunsaturated fatty acids and larger high-density lipoprotein particle sizes. Associations were consistent within the Asian ethnic groups (all Phet ≥ 0.05) and largely consistent for the Asian and European populations (Phet ≥ 0.05 for 128 of 154 metabolic biomarkers).

CONCLUSION

Metabolic biomarkers across several biological pathways were consistently associated with T2D risk in Asians and Europeans.

[Dysfunctional high-density lipoproteins in diabetes mellitus]

The risk of cardiovascular disease (CVD) in persons with type 2 diabetes mellitus (DM2) increases two to four times. One of the main factors increasing cardiovascular risk is dyslipidemia, which includes abnormalities in all lipoproteins, including high-density lipoproteins (HDL). The development of DM2 is accompanied not only by a decrease in the level of HDL, but also by significant changes in their structure. This leads to the transformation of native HDL into so-called dysfunctional or diabetic HDL, which loses their antiatherogenic, cardioprotective, anti-inflammatory and anti-diabetic properties. In poorly controlled diabetes mellitus HDL can not only lose its beneficial functions, but also acquire proatherogenic, proinflammatory ones. Diabetic HDL can contribute to the accumulation of such unfavorable qualities as increased proliferation, migration, and invasion of cancer cells. Given that HDL, in addition to participation in cholesterol transport, performs important regulatory functions in the body, there is reason to assume that structural modifications of HDL (oxidation, glycation, triglyceride enrichment, loss of HDL-associated enzymes, etc.) are one of the causes of vascular complications of diabetes.

HDL and Kidney Diseases

Serum lipid profiles, as well as HDL can be altered in patients with kidney diseases. There are various types of kidney diseases, including nephrotic syndrome and chronic kidney disease. In patients with nephrotic syndrome, plasma levels of HDL cholesterol and ApoA-I were within or below the normal limits. The HDL cholesterol: total cholesterol ratio decreased compared to healthy individuals. In patients with chronic kidney disease (CKD), reverse cholesterol transport function of HDL is impaired, and CKD also affects the composition and function of HDL. Cardiovascular disease (CVD) is the severe complication of CKD. Furthermore, HDL might also be a potential target for the prevention of cardiovascular complications associated with CKD.

CETP-inhibitors: from HDL-C to LDL-C lowering agents?

Cholesteryl ester transfer protein (CETP) is a liver-synthesized glycoprotein whose main functions are facilitating transfer of both cholesteryl esters from high-density lipoprotein (HDL) particles to apolipoprotein B (apoB)-containing particles as well as transfer of triglycerides from apoB-containing particles to HDL particles. Novel crystallographic data have shown that CETP exchanges lipids in the circulation by a dual molecular mechanism. Recently, it has been suggested that the atherosclerotic cardiovascular disease (ASCVD) benefit from CETP inhibition is the consequence of the achieved low-density lipoprotein cholesterol (LDL-C) and apoB reduction, rather than through the HDL cholesterol (HDL-C) increase. The use of CETP inhibitors is supported by genetic evidence from Mendelian randomization studies, showing that LDL-C lowering by CETP gene variants achieves equal ASCVD risk reduction as LDL-C lowering through gene proxies for statins, ezetimibe, and proprotein convertase subtilisin–kexin Type 9 inhibitors. Although first-generation CETP inhibitors (torcetrapib, dalcetrapib) were mainly raising HDL-C or had off-target effects, next generation CETP inhibitors (anacetrapib, evacetrapib) were also effective in reducing LDL-C and apoB and have been proven safe. Anacetrapib was the first CETP inhibitor to be proven effective in reducing ASCVD risk. In addition, CETP inhibitors have been shown to lower the risk of new-onset diabetes, improve glucose tolerance, and insulin sensitivity. The newest-generation CETP inhibitor obicetrapib, specifically designed to lower LDL-C and apoB, has achieved significant reductions of LDL-C up to 45%. Obicetrapib, about to enter phase III development, could become the first CETP inhibitor as add-on therapy for patients not reaching their guideline LDL-C targets.

Bioactivity of Dietary Polyphenols: The Role in LDL-C Lowering

Cardiovascular diseases are the leading causes of the death around the world. An elevation of the low-density lipoprotein cholesterol (LDL-C) level is one of the most important risk factors for cardiovascular diseases. To achieve optimal plasma LDL-C levels, clinal therapies were investigated which targeted different metabolism pathways. However, some therapies also caused various adverse effects. Thus, there is a need for new treatment options and/or combination therapies to inhibit the LDL-C level. Dietary polyphenols have received much attention in the prevention of cardiovascular diseases due to their potential LDL-C lowering effects. However, the effectiveness and potential mechanisms of polyphenols in lowering LDL-C is not comprehensively summarized. This review focused on dietary polyphenols that could reduce LDL-C and their mechanisms of action. This review also discussed the limitations and suggestions regarding previous studies.

High Density Lipoproteins: Is There a Comeback as a Therapeutic Target?

Low plasma levels of High Density Lipoprotein (HDL) cholesterol (HDL-C) are associated with increased risks of atherosclerotic cardiovascular disease (ASCVD). In cell culture and animal models, HDL particles exert multiple potentially anti-atherogenic effects. However, drugs increasing HDL-C have failed to prevent cardiovascular endpoints. Mendelian Randomization studies neither found any genetic causality for the associations of HDL-C levels with differences in cardiovascular risk. Therefore, the causal role and, hence, utility as a therapeutic target of HDL has been questioned. However, the biomarker "HDL-C" as well as the interpretation of previous data has several important limitations: First, the inverse relationship of HDL-C with risk of ASCVD is neither linear nor continuous. Hence, neither the-higher-the-better strategies of previous drug developments nor previous linear cause-effect relationships assuming Mendelian randomization approaches appear appropriate. Second, most of the drugs previously tested do not target HDL metabolism specifically so that the futile trials question the clinical utility of the investigated drugs rather than the causal role of HDL in ASCVD. Third, the cholesterol of HDL measured as HDL-C neither exerts nor reports any HDL function. Comprehensive knowledge of structure-function-disease relationships of HDL particles and associated molecules will be a pre-requisite, to test them for their physiological and pathogenic relevance and exploit them for the diagnostic and therapeutic management of individuals at HDL-associated risk of ASCVD but also other diseases, for example diabetes, chronic kidney disease, infections, autoimmune and neurodegenerative diseases.

HDL in the 21st Century: A Multifunctional Roadmap for Future HDL Research

Low high-density lipoprotein cholesterol (HDL-C) characterizes an atherogenic dyslipidemia that reflects adverse lifestyle choices, impaired metabolism, and increased cardiovascular risk. Low HDL-C is also associated with increased risk of inflammatory disorders, malignancy, diabetes, and other diseases. This epidemiologic evidence has not translated to raising HDL-C as a viable therapeutic target, partly because HDL-C does not reflect high-density lipoprotein (HDL) function. Mendelian randomization analyses that have found no evidence of a causal relationship between HDL-C levels and cardiovascular risk have decreased interest in increasing HDL-C levels as a therapeutic target. HDLs comprise distinct subpopulations of particles of varying size, charge, and composition that have several dynamic and context-dependent functions, especially with respect to acute and chronic inflammatory states. These functions include reverse cholesterol transport, inhibition of inflammation and oxidation, and antidiabetic properties. HDLs can be anti-inflammatory (which may protect against atherosclerosis and diabetes) and proinflammatory (which may help clear pathogens in sepsis). The molecular regulation of HDLs is complex, as evidenced by their association with multiple proteins, as well as bioactive lipids and noncoding RNAs. Clinical investigations of HDL biomarkers (HDL-C, HDL particle number, and apolipoprotein A through I) have revealed nonlinear relationships with cardiovascular outcomes, differential relationships by sex and ethnicity, and differential patterns with coronary versus noncoronary events. Novel HDL markers may also have relevance for heart failure, cancer, and diabetes. HDL function markers (namely, cholesterol efflux capacity) are associated with coronary disease, but they remain research tools. Therapeutics that manipulate aspects of HDL metabolism remain the holy grail. None has proven to be successful, but most have targeted HDL-C, not metrics of HDL function. Future therapeutic strategies should focus on optimizing HDL function in the right patients at the optimal time in their disease course. We provide a framework to help the research and clinical communities, as well as funding agencies and stakeholders, obtain insights into current thinking on these topics, and what we predict will be an exciting future for research and development on HDLs.

HDL Particle Subspecies and Their Association With Incident Type 2 Diabetes: The PREVEND Study

CONTEXT

High-density lipoproteins (HDL) may be protective against type 2 diabetes (T2D) development, but HDL particles vary in size and function, which could lead to differential associations with incident T2D. A newly developed nuclear magnetic resonance (NMR)-derived algorithm provides concentrations for 7 HDL subspecies.

OBJECTIVE

We aimed to investigate the association of HDL particle subspecies with incident T2D in the general population.

METHODS

Among 4828 subjects of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study without T2D at baseline, HDL subspecies with increasing size from H1P to H7P were measured by NMR (LP4 algorithm of the Vantera NMR platform).

RESULTS

A total of 265 individuals developed T2D (median follow-up of 7.3 years). In Cox regression models, HDL size and H4P (hazard ratio [HR] per 1 SD increase 0.83 [95% CI, 0.69-0.99] and 0.85 [95% CI, 0.75-0.95], respectively) were inversely associated with incident T2D, after adjustment for relevant covariates. In contrast, levels of H2P were positively associated with incident T2D (HR 1.15 [95% CI, 1.01-1.32]). In secondary analyses, associations with large HDL particles and H6P were modified by body mass index (BMI) in such a way that they were particularly associated with a lower risk of incident T2D, in subjects with BMI < 30 kg/m2.

CONCLUSION

Greater HDL size and lower levels of H4P were associated with a lower risk, whereas higher levels of H2P were associated with a higher risk of developing T2D. In addition, large HDL particles and H6P were inversely associated with T2D in nonobese subjects.

Prominent and emerging anti-diabetic molecular targets

Diabetes is on the rise across the globe affecting more than 463 million people and crucially increasing morbidities of diabetes-associated diseases. Urgent and immense actions are needed to improve diabetes prevention and treatment. Regarding the correlation of diabetes with many associated diseases, inhibition of the disease progression is more crucial than controlling symptoms. Currently, anti-diabetic drugs are accompanied by undesirable side-effects and target confined types of biomolecules. Thus, extensive research is demanding to identify novel disease mechanisms and molecular targets as probable candidates for effective treatment of diabetes. This review discusses the conventional molecule targets that have been applied for their therapeutic rationale in treatment of diabetes. Further, the emerging and prospective molecular targets for the future focus of library screenings are presented.

Effect of bempedoic acid on new onset or worsening diabetes: A meta-analysis

INTRODUCTION

Bempedoic acid is a new agent that reduces low-density lipoprotein cholesterol. Since inhibits cholesterol synthesis through a different mechanism than statins, the adverse effects related to it may also be different. Therefore, the objective of the present meta-analysis was to evaluate the effect of bempedoic acid on new onset or worsening diabetes.

METHODS

We performed a meta-analysis including randomized trials of bempedoic acid therapy, reporting new onset or worsening diabetes with a minimum of 4 weeks of follow-up. The fixed-effects model was performed. This meta-analysis was performed according to PRISMA guidelines.

RESULTS

Five eligible trials of bempedoic acid, including 3629 patients, were identified and considered eligible for the analyses. A total of 2419 subjects were allocated to receive bempedoic acid while 1210 subjects were allocated to the respective control arms. Bempedoic acid therapy is associated with a significant reduction in new onset or worsening diabetes [Odds Ratio: 0.66, 95% confidence interval: 0.48-0.90; I2: 0%].

CONCLUSION

This data suggests that the use of bempedoic acid significantly reduces the new onset or worsening diabetes risk. This finding should be confirmed with future studies.

Cardioprotective Properties of HDL: Structural and Functional Considerations

BACKGROUND

As Mendelian Randomization (MR) studies showed no effect of variants altering HDL-cholesterol (HDL-C) levels concerning Cardiovascular Disease (CVD) and novel therapeutic interventions aiming to raise HDL-C resulted to futility, the usefulness of HDL-C is unclear.

OBJECTIVE

As the role of HDL-C is currently doubtful, it is suggested that the atheroprotective functions of HDLs can be attributed to the number of HDL particles, and their characteristics including their lipid and protein components. Scientific interest has focused on HDL function and on the causes of rendering HDL particles dysfunctional, whereas the relevance of HDL subclasses with CVD remains controversial.

METHODS

The present review discusses changes in quality as much as in quantity of HDL in pathological conditions and the connection between HDL particle concentration and cardiovascular disease and mortality. Emphasis is given to the recently available data concerning the cholesterol efflux capacity and the parameters that determine HDL functionality, as well as to recent investigations concerning the associations of HDL subclasses with cardiovascular mortality.

RESULTS

MR studies or pharmacological interventions targeting HDL-C are not in favor of the hypothesis of HDL-C levels and the relationship with CVD. The search of biomarkers that relate with HDL functionality is needed. Similarly, HDL particle size and number exhibit controversial data in the context of CVD and further studies are needed.

CONCLUSION

There is no room for the old concept of HDL as a silver bullet,as HDL-C cannot be considered a robust marker and does not reflect the importance of HDL particle size and number. Elucidation of the complex HDL system, as well as the finding of biomarkers, will allow the development of any HDL-targeted therapy.

High-Density Lipoprotein Particles and Their Relationship to Posttransplantation Diabetes Mellitus in Renal Transplant Recipients

High concentrations of high-density lipoprotein (HDL) cholesterol are likely associated with a lower risk of posttransplantation diabetes mellitus (PTDM). However, HDL particles vary in size and density with yet unestablished associations with PTDM risk. The aim of our study was to determine the association between different HDL particles and development of PTDM in renal transplant recipients (RTRs). We included 351 stable outpatient adult RTRs without diabetes at baseline evaluation. HDL particle characteristics and size were measured by nuclear magnetic resonance (NMR) spectroscopy. During 5.2 (IQR, 4.1‒5.8) years of follow-up, 39 (11%) RTRs developed PTDM. In multivariable Cox regression analysis, levels of HDL cholesterol (hazard ratio [HR] 0.61, 95% confidence interval [CI] 0.40-0.94 per 1SD increase; p = 0.024) and of large HDL particles (HR 0.68, 95% CI 0.50-0.93 per log 1SD increase; p = 0.017), as well as larger HDL size (HR 0.58, 95% CI 0.36-0.93 per 1SD increase; p = 0.025) were inversely associated with PTDM development, independently of relevant covariates including, age, sex, body mass index, medication use, transplantation-specific parameters, blood pressure, triglycerides, and glucose. In conclusion, higher concentrations of HDL cholesterol and of large HDL particles and greater HDL size were associated with a lower risk of PTDM development in RTRs, independently of established risk factors for PTDM development.

Elevated Cholesteryl Ester Transfer Protein Activity Early in Pregnancy Predicts Prediabetes 5 Years Later

CONTEXT

Cholesteryl ester transfer protein (CETP) regulates high-density lipoprotein (HDL) cholesterol levels and interaction between glucose, and HDL metabolism is central in the development of diabetes.

OBJECTIVE

We hypothesized that CETP levels would be regulated in diabetic pregnancies. We tested the hypothesis by evaluating CETP activity measured multiple times during pregnancy and at 5 years' follow-up in a prospective cohort (STORK) and investigated its association with gestational diabetes mellitus (GDM) during pregnancy or development of prediabetes 5 years after pregnancy. We also evaluated the strongest correlation of CETP activity among measures of adipocity and glucose metabolism, lipoproteins, adipokines, and monocyte/macrophage activation markers.

DESIGN

A population-based longitudinal cohort study was conducted from 2001 to 2013.

SETTING

The study setting was Oslo University Hospital.

PATIENTS OR OTHER PARTICIPANTS

A total of 300 women during pregnancy and at 5 years postpartum participated in this study.

MAIN OUTCOME MEASURES

CETP activity was measured at 14 to 16, 22 to 24, 30 to 32, and 36 to 38 weeks' gestation, and at 5 years' follow-up.

RESULTS

We found higher CETP activity in pregnancy in women developing prediabetes but no association with GDM. CETP activity decreased throughout pregnancy and remained low at follow-up. High CETP activity was associated with sCD14 levels, in particular in women who developed prediabetes. These data show that enhanced CETP activity during pregnancy is associated with systemic indices of monocyte/macrophage activation, in particular in women who develop prediabetes later in life.

CONCLUSIONS

CETP activity during pregnancy identifies women at risk for later diabetes development.

Cholesteryl Ester Transfer Protein and Lipid Metabolism and Cardiovascular Diseases

In this chapter, we present the major advances in CETP research since the detection, isolation, and characterization of its activity in the plasma of humans and several species. Since CETP is a major modulator of HDL plasma levels, the clinical importance of CETP activity was recognized very early. We describe the participation of CETP in reverse cholesterol transport, conflicting results in animal and human genetic studies, possible new functions of CETP, and the results of the main clinical trials on CETP inhibition. Despite major setbacks in clinical trials, the hypothesis that CETP inhibitors are anti-atherogenic in humans is still being tested.

Rethinking good cholesterol: a clinicians' guide to understanding HDL

Low HDL cholesterol dyslipidaemia affects about half of people with type 2 diabetes and represents a major independent risk factor for atherosclerotic cardiovascular disease. The "good cholesterol" label was coined decades ago on the basis of a presumed causal role of HDL cholesterol in atherosclerotic cardiovascular disease. However, this view has been challenged by the negative results of several studies of HDL cholesterol-raising drugs, creating a paradox for clinicians regarding the value of HDL cholesterol as a risk biomarker and therapeutic target, and seemingly contradicting decades of evidence substantiating an inverse relation between HDL cholesterol and cardiovascular disease risk. We seek to resolve this issue by revisiting the history of the HDL hypothesis, chronicling how this paradox is ultimately rooted in the progressive erroneous blurring of the distinction between HDL and HDL cholesterol. We describe the compositional complexity of HDL particles beyond their cholesterol cargo and focus on their role in lipid transport. We discuss the evidence regarding novel HDL functions, including effects on glucose metabolism, and speculate on the implications for type 2 diabetes. HDL cholesterol is an imperfect biomarker of a highly complex and multifunctional lipid transport system, and we should now consider how new HDL markers more causally linked to cardiovascular complications could be adapted for clinical use. In the absence of a superior alternative, HDL cholesterol generally has value as a component of primary cardiovascular disease risk prediction models, including in people with type 2 diabetes. However, to avoid prognostic overgeneralisations, it is high time that the good cholesterol label is dropped.

High-Density Lipoprotein Subspecies in Health and Human Disease: Focus on Type 2 Diabetes

Plasma cholesterol levels of high-density lipoproteins (HDL) have been associated with cardioprotection for decades. However, there is an evolving appreciation that this lipoprotein class is highly heterogeneous with regard to composition and functionality. With the advent of advanced lipid-testing techniques and methods that allow both the quantitation and recovery of individual particle populations, we are beginning to connect the functionality of HDL subspecies with chronic metabolic diseases. In this review, we examine type 2 diabetes (T2D) and explore our current understanding of how obesity, insulin resistance, and hyperglycemia affect, and may be affected by, HDL subspeciation. We discuss mechanistic aspects of how insulin resistance may alter lipoprotein profiles and how this may impact the ability of HDL to mitigate both atherosclerotic disease and diabetes itself. Finally, we call for more detailed studies examining the impact of T2D on specific HDL subspecies and their functions. If these particles can be isolated and their compositions and functions fully elucidated, it may become possible to manipulate the levels of these specific particles or target the protective functions to reduce the incidence of coronary heart disease.

Do Cholesteryl Ester Transfer Protein Inhibitors Have a Role in the Treatment of Cardiovascular Disease?

Cholesteryl ester transfer protein (CETP) plays an important role in lipid metabolism and has presented an attractive target for drug development, primarily resting on the hope that CETP inhibition would reduce cardiovascular events through its ability to increase levels of high-density lipoprotein cholesterol (HDL-C). However, clinical development of CETP inhibitors has proven disappointing, with a spectrum of results spanning from evidence of harm, to futility, to only modest benefit in large-scale cardiovascular outcomes trials. A number of additional insights from genomic studies have suggested potential benefits from these agents in specific clinical settings. We review the current state of CETP inhibitors as an approach to targeting cardiovascular risk.

Residual cardiovascular risk among people with diabetes

Type 2 diabetes (T2D) is a growing health concern across both developed and developing countries. Cardiovascular disease (CVD) remains the major cause of increased mortality in this patient population. In recent years, effective low density lipoprotein lowering treatments and other risk reduction strategies have substantially reduced the risk of atherosclerotic CVD, yet patients with T2D continue to remain at increased risk for atherosclerotic CVD. Here, we will briefly review various proposed underlying mechanisms for this residual risk with a more in-depth focus on the potential role of triglyceride-rich lipoproteins in residual risk and potential avenues to target this pharmacologically.

Gender specific effect of CETP rs708272 polymorphism on lipid and atherogenic index of plasma levels but not on the risk of coronary artery disease: A case-control study

Numerous studies have shown a relationship between cholesteryl ester transfer protein (CETP) polymorphism in the synthesis of high-density lipoprotein cholesterol (HDL-C) and the coronary artery disease (CAD) susceptibility, but the results have remained inconsistent. In addition, there was no study exploring the relationship between CETP polymorphisms and atherogenic index of plasma (AIP) levels.We conducted a case-control study to evaluate the relationship between CETP rs708272 polymorphism and CAD risk and lipid levels in Chinese Han population. 556 CAD patients and 414 controls undergoing coronary angiography were consecutively enrolled in the hospital-based study. Polymerase chain reaction-ligase detection reaction (PCR-LDR) method was used to detect the different genotypes at rs708272.No significant association between CETP rs708272 polymorphism and CAD risk was observed in different genetic models. In the whole population, participants with TT genotype had higher HDL-C levels (1.17 ± 0.31 mmol/L vs 1.09 ± 0.29 mmol/L, P = .001) and lower AIP levels (0.08 ± 0.35 vs 0.16 ± 0.31, P = .004) compared to those with CC genotype, after adjusting for age, gender, smoking, essential hypertension (EH), and DM. The T allele carriers had higher HDL-C levels than the T allele non-carriers (1.13 ± 0.29 mmol/L vs 1.09 ± 0.29 mmol/L, P = .023). Furthermore, subgroup analyses based on gender were carried out. In males, the results showed that participants with TT genotype had significant higher HDL-C levels and lower AIP levels compared with CC genotype (P <.05). In addition, males with CT+TT genotypes had higher HDL-C levels and lower AIP levels than those with CC genotypes (HDL-C: CT+TT 1.11 ± 0.31vs CC 1.06 ± 0.30 mmol/L, P = .041; AIP: CT+TT 0.12 ± 0.32vs CC 0.16 ± 0.31, P = .034, respectively). However, there were no significant associations between lipid levels and CETP rs708272 polymorphism in females, after adjusting for confounders.CETP rs708272 polymorphism has a gender-specific effect on lipid and AIP levels but not on the risk of CAD.

CETP inhibition, statins and diabetes

Type 2 diabetes is a causal risk factor for the development of atherosclerotic cardiovascular disease (ASCVD). While treatment with a statin reduces the risk of having an ASCVD event in all people, including those with type-2 diabetes, statin treatment also increases the likelihood of new onset diabetes when given to those with risk factors for developing diabetes. Treatment with the cholesteryl ester transfer protein (CETP) inhibitor, anacetrapib, reduces the risk of having a coronary event over and above that achieved with a statin. However, unlike statins, anacetrapib decreases the risk of developing diabetes. If the reduced risk of new-onset diabetes is confirmed in another CETP inhibitor outcome trial, there will be a case for considering the use of the combination of a statin plus a CETP inhibitor in high ASCVD-risk people who are also at increased risk of developing diabetes.