Fenofibrate, HDL, and cardiovascular disease in Type-2 diabetes: The DAIS trial

Haptoglobin phenotype and levels in type 2 diabetes and effects of fenofibrate

AIMS/HYPOTHESIS

In diabetes haptoglobin (Hp) 2 vs Hp 1 allelic product is associated with cardiac and renal complications. Few studies report both Hp phenotype and Hp levels. In a Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial substudy we evaluated the Hp phenotype, Hp levels, and fenofibrate effects.

MATERIALS AND METHODS

In 480 adults with type 2 diabetes (T2D) the Hp phenotype was assessed and the Hp level quantified (both using ELISAs assays) in plasma from baseline, after 6 weeks of fenofibrate, and (in n = 200) at 2 years post-randomization to fenofibrate or placebo.

RESULTS

The Hp phenotypes 1-1, 2-1, and 2-2 frequencies were 15%, 49%, and 36%, respectively. Baseline Hp levels differed by phenotype (P < 0.0001) and decreased (median 21%) after 6 weeks fenofibrate in all phenotypes (adjusted mean (95% CI): -0.27 (-0.32, -0.23) mg/mL in Hp 1-1, -0.29 (-0.31, -0.27) mg/mL in Hp 2-1 and -0.05 (-0.07, -0.02) mg/mL in Hp 2-2 (P = 0.005 and P = 0.055 vs Hp 1-1 and Hp 2-1, respectively)). At 2 years post-randomization the Hp levels in the placebo group had returned to baseline, whilst the fenofibrate-group levels remained similar to the 6 week levels.

CONCLUSIONS

In type 2 diabetes, Hp levels differ by Hp phenotype and are decreased by fenofibrate in all phenotypes, but the effect is diminished in Hp 2-2.

A significant presence in atherosclerotic cardiovascular disease: Remnant cholesterol: A review

The current first-line treatment for atherosclerotic cardiovascular disease (ASCVD) involves the reduction of a patient's low-density lipoprotein cholesterol (LDL-C) levels through the use of lipid-lowering drugs. However, even when other risk factors such as hypertension and diabetes are effectively managed, there remains a residual cardiovascular risk in these patients despite achieving target LDL-C levels with statins and new lipid-lowering medications. This risk was previously believed to be associated with lipid components other than LDL, such as triglycerides. However, recent studies have unveiled the crucial role of remnant cholesterol (RC) in atherosclerosis, not just triglycerides. The metabolized product of triglyceride-rich lipoproteins is referred to as triglyceride-rich remnant lipoprotein particles, and its cholesterol component is known as RC. Numerous pieces of evidence from epidemiological investigations and genetic studies demonstrate that RC plays a significant role in predicting the incidence of ASCVD. As a novel marker for atherosclerosis prediction, when LDL-C is appropriately controlled, RC should be prioritized for attention and intervention among individuals at high risk of ASCVD. Therefore, reducing RC levels through the use of various lipid-lowering drugs may yield long-term benefits. Nevertheless, routine testing of RC in clinical practice remains controversial, necessitating further research on the treatment of elevated RC levels to evaluate the advantages of reducing RC in patients at high risk of ASCVD.

The effect of lipid-lowering therapy on lipid-related residual risk factors: a prospective study

BACKGROUND

Remnant cholesterol (RC) and nonhigh-density lipoprotein cholesterol (nonHDL-C) are key risk factors for atherosclerotic cardiovascular disease (ASCVD), with apolipoprotein B (apoB) and lipoprotein(a) [Lp(a)] also contributing to its residual risk. However, real-world population-based evidence regarding the impact of current clinical LDL-C-centric lipid-lowering therapy (LLT) on achieving RC and nonHDL-C goals, as well as on modifying residual CVD risk factors is limited.

METHODS

This prospective observational study enrolled 897 CVD patients from September, 2020 to July, 2021. All participants had previously received low-/moderate-intensity LLT and were discharged with either low-/moderate-intensity LLT or high-intensity LLT. After a median follow-up of 3 months, changes in RC, nonHDL-C, and other biomarkers were assessed. Multivariate logistic regression was performed to analyze the impact of the LLT on goal attainment.

RESULTS

Among all patients, 83.50% transitioned to high-intensity LLT from low or moderate. After follow-up, the high-intensity group saw significantly greater reductions in RC (-20.51% vs. -3.90%, P = 0.025), nonHDL-C (-25.12% vs. 0.00%, P < 0.001), apoB (-19.35% vs. -3.17%, P < 0.001), triglycerides (-17.82% vs. -6.62%, P < 0.001), and LDL-C and total cholesterol. Spearman correlation analysis revealed that LDL-C reduction from current LLT was strongly correlated with nonHDL-C reduction (r = 0.87, P < 0.001). Patients who received high-intensity LLT had significant improvements in attainment of RC (from 44.2% to 60.7%, χ² = 39.23, P < 0.001) and nonHDL-C (from 19.4% to 56.9%, χ² = 226.06, P < 0.001) goals. Furthermore, multivariate logistic regression showed that high-intensity LLT was a protective factor for RC [odds ratio (OR) = 0.66; 95% confidence intervals (CI), 0.45-0.97; P = 0.033] and nonHDL-C goal attainment (OR = 0.51; 95% CI, 0.34-0.75; P < 0.001), without a significant increase of adverse reactions.

CONCLUSION

Current levels of clinically prescribed LDL-C-centric treatment can reduce RC and other lipid-related residual risk factors, but high-intensity LLT is better at achieving nonHDL-C and RC goals than low-/moderate-intensity LLT, with a good safety profile. More targeted RC treatments are still needed to reduce residual lipid risk further.

Effects of elevated remnant cholesterol on outcomes of acute ischemic stroke patients receiving mechanical thrombectomy

OBJECTIVE

Large cohort studies provided evidence that elevated remnant cholesterol (RC) was an important risk factor for ischemic stroke. However, the association between high RC and clinical outcomes in acute ischemic stroke (AIS) individuals was still undetermined.

METHODS

This retrospective study enrolled 165 AIS patients undergoing mechanical thrombectomy in one tertiary stroke center. We divided patients into two groups based on the median of their RC levels (0.49 mmol/L). The modified Rankin Scale (mRS) was used to evaluate the primary outcome 90 days after the onset of symptoms. The mRS scores ≤ 2 and ≤ 1 at 90 days were deemed as favorable and excellent outcomes, respectively.

RESULTS

In the overall AIS patients undergoing mechanical thrombectomy, there was no obvious distinction between the high and low RC group at 90-day favorable outcome (41.0% vs. 47.1%, P = 0.431) or excellent outcome (23.1% vs. 31.0%, P = 0.252). In the subgroup analysis stratified by stroke etiology, non-large artery atherosclerosis (non-LAA) stroke patients yielded with less favorable or excellent prognosis in the high RC group (26.8% vs. 46.8%, adjusted OR = 0.31, 95%CI: 0.11-0.85, P = 0.023; or 12.2% vs. 29.0%, adjusted OR = 0.18, 95%CI: 0.04-0.80, P = 0.024, respectively.). Post hoc power analyses indicated that the power was sufficient for favorable outcome (80.38%) and excellent outcome (88.72%) in non-LAA stroke patients. Additionally, RC can enhance the risk prediction value of a poor outcome (mRS scores 3-6) based on traditional risk indicators (including age, initial NIHSS score, operative duration, and neutrophil-to-lymphocyte ratio) for non-LAA stroke patients (AUC = 0.86, 95%CI: 0.79-0.94, P < 0.001).

CONCLUSION

In AIS patients undergoing mechanical thrombectomy, elevated RC was independently related to poor outcome for non-LAA stroke patients, but not to short-term prognosis of LAA stroke patients.

Effect of Fibrate Treatment on Circulating Adipokine Levels: A Systematic Review and Meta-analysis of Randomized Clinical Trials

BACKGROUND

Fibrates are widely used in the treatment of dyslipidemia and associated metabolic abnormalities; however, their effects on adipokines are unclear.

AIM OF THE STUDY

This meta-analysis of clinical trials aimed to evaluate the effect of fibrates on circulating adipokine levels.

METHODS

Only randomized controlled trials investigating the impact/effect of fibrate treatment on circulating adipokine levels were included from searches in PubMed-Medline, SCOPUS, ClinicalTrials.gov, Web of Science, and Google Scholar databases. A random effects model and the generic inverse variance method were used for the meta-analysis. Sensitivity analysis was conducted using the leave-one-out method.

RESULTS

This meta-analysis of 22 clinical trials showed a significant reduction on/in leptin (WMD: -1.58 ng/mL, 95% CI: -2.96, -0.20, p = 0.02, I2 = 0%), plasminogen activator inhibitor-1 (PAI-1) (WMD: -13.86 ng/mL, 95% CI: -26.70, -1.03, p = 0.03, I2 = 99%), and visfatin (WMD: -1.52 ng/mL, 95% CI: -2.49, -0.56, p = 0.002, I2 = 0%) after fibrate therapy; no significant effect was observed on adiponectin (WMD: -0.69 µg/ml, 95% CI: -1.40, 0.02, p = 0.06, I2 = 83%) and resistin (WMD: -2.27 ng/mL, 95% CI: -7.11, 2.57, p = 0.36, I2 = 0%). The sensitivity analysis was robust only for visfatin, while the effect size was sensitive to one arm for leptin, four for adiponectin, and two for PAI-1.

CONCLUSION

This meta-analysis showed that fibrate treatment significantly improves adipokine levels with a decrease in leptin, PAI-1, and visfatin, suggesting potential additional clinical therapeutic benefits through/of fibrate treatment on adipose tissue.

Fenofibrate reduces glucose-induced barrier dysfunction in feline enteroids

Diabetes mellitus (DM) is a common chronic metabolic disease in humans and household cats that is characterized by persistent hyperglycemia. DM is associated with dysfunction of the intestinal barrier. This barrier is comprised of an epithelial monolayer that contains a network of tight junctions that adjoin cells and regulate paracellular movement of water and solutes. The mechanisms driving DM-associated barrier dysfunction are multifaceted, and the direct effects of hyperglycemia on the epithelium are poorly understood. Preliminary data suggest that fenofibrate, An FDA-approved peroxisome proliferator-activated receptor-alpha (PPARα) agonist drug attenuates intestinal barrier dysfunction in dogs with experimentally-induced DM. We investigated the effects of hyperglycemia-like conditions and fenofibrate treatment on epithelial barrier function using feline intestinal organoids. We hypothesized that glucose treatment directly increases barrier permeability and alters tight junction morphology, and that fenofibrate administration can ameliorate these deleterious effects. We show that hyperglycemia-like conditions directly increase intestinal epithelial permeability, which is mitigated by fenofibrate. Moreover, increased permeability is caused by disruption of tight junctions, as evident by increased junctional tortuosity. Finally, we found that increased junctional tortuosity and barrier permeability in hyperglycemic conditions were associated with increased protein kinase C-α (PKCα) activity, and that fenofibrate treatment restored PKCα activity to baseline levels. We conclude that hyperglycemia directly induces barrier dysfunction by disrupting tight junction structure, a process that is mitigated by fenofibrate. We further propose that counteracting modulation of PKCα activation by increased intracellular glucose levels and fenofibrate is a key candidate regulatory pathway of tight junction structure and epithelial permeability.

Remnant cholesterol in atherosclerotic cardiovascular disease: A systematic review and meta-analysis

BACKGROUND

Accumulating evidence suggests a substantial contribution of remnant cholesterol (RC) to residual risk for the development or relapse of atherosclerotic cardiovascular disease (ASCVD). We aimed to evaluate the association of RC levels with ASCVD risk by different risk categories and methods of RC assessment. We also assessed available evidence of the effects of lipid-lowering therapies (LLTs) on RC levels.

METHODS

English-language searches of Medline, PubMed, and Embase (inception to 31 January 2023); ClinicalTrials.gov (October 2022); and reference lists of studies and reviews. Studies reporting on the risk of the composite endpoint [all-cause mortality, cardiovascular mortality, and major adverse cardiac events (MACE)] by RC levels were included. Moreover, we searched for studies reporting differences in RC levels after the administration of LLT(s).

RESULTS

Among n = 29 studies with 257,387 participants, we found a pooled linear (pooled HR: 1.27 per 1-SD increase, 95% CI: 1.12-1.43, P < 0.001, I2 = 95%, n = 15 studies) and non-linear association (pooled HR: 1.59 per quartile increase, 95% CI: 1.35-1.85, P < 0.001, I2 = 87.9%, n = 15 studies) of RC levels and the risk of M ACE both in patients with and without established ASCVD. Interestingly, the risk of MACE was higher in studies with directly measured vs. calculated RC levels. In a limited number of studies and participants, LLTs reduced RC levels.

CONCLUSION

RC levels are associated with ASCVD risk both in primary and secondary prevention. Directly measured RC levels are associated with ASCVD risk more evidently. Available LLTs tend to decrease RC levels, although the clinical relevance of RC decrease merits further investigation.

PROSPERO REGISTRATION

CRD42022371346.

Significance of Circulating Remnant Lipoprotein Cholesterol Levels Measured by Homogeneous Assay in Patients with Type 2 Diabetes

Remnant lipoproteins (RLs), which are typically present at high concentrations in patients with type 2 diabetes mellitus (T2DM), are associated with cardiovascular disease (CVD). Although an RL cholesterol homogeneous assay (RemL-C) is available for the measurement of RL concentrations, there have been no studies of the relationship between RemL-C and clinical parameters in T2DM. Therefore, we evaluated the relationships between RemL-C and CVD-related parameters in patients with T2DM. We performed a cross-sectional study of 169 patients with T2DM who were hospitalized at Kumamoto University Hospital. Compared with those with low RemL-C, those with higher RemL-C had higher fasting plasma glucose, homeostasis model assessment for insulin resistance (HOMA-R), total cholesterol, triglyceride, small dense low-density lipoprotein cholesterol (sdLDL-C), and urinary albumin-creatinine ratio; and lower high-density lipoprotein cholesterol, adiponectin, and ankle brachial pressure index (ABI). Multivariate logistic regression analysis showed that sdLDL-C and ABI were significantly and independently associated with high RemL-C. Although LDL-C was lower in participants with CVD, there was no difference in RemL-C between participants with or without CVD. Thus, RemL-C may represent a useful index of lipid and glucose metabolism, and that may be a marker of peripheral atherosclerotic disease (PAD) in male patients with T2DM.

Remnant cholesterol and atherosclerotic cardiovascular disease: Metabolism, mechanism, evidence, and treatment

This review aimed to summarize the evidence of elevated remnant cholesterol and the risks of atherosclerotic cardiovascular disease (ASCVD) and to search for further guidance in clinical therapy. The lipids-lowering treatments such as statins and ezetimibe targeted on low-density lipoprotein cholesterol (LDL-C) have always been the first-line therapy for ASCVD. However, even after statins or new lipid-lowering drugs lowered LDL-C to recommended concentrations, and with other risk factors well-controlled, such as high blood pressure, the risks of developing ASCVD remained. Remnant cholesterol (RC) referred to the cholesterol contained in all remnant lipoprotein particles, which was the cholesterol in the hydrolyzed very-low-density lipoprotein and intermediate-density lipoprotein in the fasting state, and the cholesterol in the chylomicron remnants in the postprandial state. Evidence from in vitro and animal pathogenic mechanisms studies, epidemiology, and genetic studies all indicated that RC played an important role in predicting the incidence of ASCVD. As a new indicator to reflect atherosclerosis, especially when LDL-C has been controlled to a recommended level, RC was considered as a priority treatment target for people at high risk of ASCVD. The use of statins, fibrates, APOC3 inhibitors, PCSK9 inhibitors, and omega-3 fatty acids to reduce RC levels in the plasma may provide long-term benefits. However, the standardized detection of RC was still controversial, and more studies on appropriate treatments of elevated RC are urgently needed. These positive trials may benefit more patients at high ASCVD risks worldwide in the future.

Fenofibrate enhances lipid deposition via modulating PPARγ, SREBP-1c, and gut microbiota in ob/ob mice fed a high-fat diet

Obesity is characterized by lipid accumulation in distinct organs. Presently, fenofibrate is a commonly used triglyceride-lowering drug. This study is designed to investigate whether long-term fenofibrate intervention can attenuate lipid accumulation in ob/ob mouse, a typical model of obesity. Our data demonstrated that fenofibrate intervention significantly decreased plasma triglyceride level by 21.0%, increased liver index and hepatic triglyceride content by 31.7 and 52.1%, respectively, and elevated adipose index by 44.6% compared to the vehicle group. As a PPARα agonist, fenofibrate intervention significantly increased the expression of PPARα protein in the liver by 46.3% and enhanced the expression of LDLR protein by 3.7-fold. However, fenofibrate dramatically increased the expression of PPARγ and SREBP-1c proteins by ~2.1- and 0.9-fold in the liver, respectively. Fenofibrate showed no effects on the expression of genes-related to fatty acid β-oxidation. Of note, it significantly increased the gene expression of FAS and SCD-1. Furthermore, fenofibrate modulated the gut microbiota. Collectively, long-term fenofibrate induces lipid accumulation in liver and adipose tissues in ob/ob mice by enhancing the expression of adipogenesis-related proteins and gut microbiota. These data suggest that fenofibrate may have limited effects on attenuating lipid deposition in obese patients.

Potential Therapeutic Agents That Target ATP Binding Cassette A1 (ABCA1) Gene Expression

The cholesterol efflux protein ATP binding cassette protein A1 (ABCA) and apolipoprotein A1 (apo A1) are key constituents in the process of reverse-cholesterol transport (RCT), whereby excess cholesterol in the periphery is transported to the liver where it can be converted primarily to bile acids for either use in digestion or excreted. Due to their essential roles in RCT, numerous studies have been conducted in cells, mice, and humans to more thoroughly understand the pathways that regulate their expression and activity with the goal of developing therapeutics that enhance RCT to reduce the risk of cardiovascular disease. Many of the drugs and natural compounds examined target several transcription factors critical for ABCA1 expression in both macrophages and the liver. Likewise, several miRNAs target not only ABCA1 but also the same transcription factors that are critical for its high expression. However, after years of research and many preclinical and clinical trials, only a few leads have proven beneficial in this regard. In this review we discuss the various transcription factors that serve as drug targets for ABCA1 and provide an update on some important leads.

Comparative Analysis of the Quality of Life Scales Parameters in Patients with Combination of Stable Ischemic Heart Disease and Metabolic Syndrome

Modern epidemiological studies confirm that comorbid diseases and conditions can have significant impact on diagnostic and treatment of the underlying disease. The problem of the comorbidy of stable coronary heart disease (SCHD) and metabolic syndrome (MS) has high medical and social significance, need high costs for diagnosis and treatment, and leads to decreased of quality of life (QOL). QOL is an important indicator of the health status of patients, which comprehensively characterizes human physical, psychological, emotional and social functioning. The objective: to conduct a comparative analysis of the QOL of patients with combination of SCAD and MS versus patients with isolated SCHD. Materials and methods. The study included 102 patients: 52 people with MS in combination with SCAD and 50 patients with SCHD only. There were 42 (51.2%) men (mean age 49.8 ± 5.3 years), and 40 (48.8%) women (mean age 51.6 ± 6.7 years). The QoL score was assessed by general medical questionnaire – the Medical Outcomes Study 36-Item (SF-36), in which all scales form two indicators: mental and physical health and a specialized questionnaire for patient with stable angina pectoris – SAQ (Seattle Angina Questionnaire). The diagnosis of SCHD with functional class (FC) assessment was performed by European Society of Cardiology criteria. MS was established if three out of five diagnostic criteria were met. Results. Patients with comorbid MS and SCHD demonstrated significantly lower QoL scores, both in psychological and physical components of health (according to the SF-36 questionnaire) compared to patients with SCHD alone (p <0.05). An analysis of the SAQ questionnaire data also showed significantly lower points in group of patients with NAS and SCHD combination compared to the group of patients with isolated SCHD (in total, by 8.76%; p <0.05). Conclusion. Patients with metabolic syndrome in combination with stable coronary heart disease (SCHD) had a statistically significantly lower level of quality of life according to the evaluation by both SF-36 nonspecific questionnaire and the SAQ specific questionnaire comparing to group of patients with isolated SCAD.

Efficacy and Safety of Fenofibrate-Statin Combination Therapy in Patients With Inadequately Controlled Triglyceride Levels Despite Previous Statin Monotherapy: A Multicenter, Randomized, Double-blind, Phase IV Study

PURPOSE

Residual cardiovascular risk reduction by fenofibrate in patients with high serum triglyceride (TG) levels despite previous statin monotherapy is not well characterized. The purpose of this study was to evaluate the efficacy and safety of a combination of choline fenofibrate and statin in patients with inadequately controlled TG levels despite previous statin monotherapy.

METHODS

This prospective, multicenter, randomized, double-blind study was conducted in Korea. A total of 133 patients with controlled LDL-C but elevated TG levels, already receiving statin monotherapy, were enrolled in the study, which was conducted from July 2018 to December 2019. Patients were randomly assigned to receive combination therapy with choline fenofibrate and statin or statin monotherapy in a 1:1 ratio. After 8 weeks of treatment, the lipid profiles and safety parameters of the patients in the 2 groups were compared.

FINDINGS

The study included 127 patients (64 in the combination group and 63 in the control group) older than 19 years. After 8 weeks of therapy, mean serum TG levels significantly decreased from 269.8 to 145.5 mg/dL (P < 0.0001) in the combination therapy group, whereas no significant changes occurred in the statin monotherapy group (from 271.1 to 280.5 mg/dL). Contrarily, the mean serum HDLC levels significantly increased from 45.0 to 50.4 mg/dL (P = 0.0004) in the combination therapy group, whereas there were no significant changes in the monotherapy group (from 44.3 to 44.7 mg/dL). There were no additional serious adverse events in the combination therapy group compared with the statin monotherapy group.

IMPLICATIONS

The combination therapy using choline fenofibrate and statin was found to be effective in serum TG control and likely tolerable in patients with high TG levels despite statin monotherapy. A larger study, conducted for a longer duration, is needed to evaluate the effectiveness of this combination in reducing cardiovascular risk. ClinicalTrials.gov identifier: NCT03874260.

Environmental Factors Modifying HDL Functionality

BACKGROUND

Currently, it has been recognized that High-Density Lipoproteins (HDL) functionality plays a much more essential role in protection from atherosclerosis than circulating HDL-cholesterol (HDL-C) levels per se. Cholesterol efflux from macrophages to HDL, cholesterol efflux capacity (CEC) has been shown to be a key metric of HDL functionality. Thus, quantitative assessment of CEC may be an important tool for the evaluation of HDL functionality, as improvement of HDL function may lead to a reduction of the risk for Cardiovascular disease (CVD).

INTRODUCTION

Although the cardioprotective action of HDLs is exerted mainly through their involvement in the reverse cholesterol transport (RCT) pathway, HDLs also have important anti-inflammatory, antioxidant, antiaggregatory and anticoagulant properties that contribute to their favorable cardiovascular effects. Certain genetic, pathophysiologic, disease states and environmental conditions may influence the cardioprotective effects of HDL either by inducing modifications in lipidome and/or protein composition or in the enzymes responsible for HDL metabolism. On the other hand, certain healthy habits or pharmacologic interventions may actually favorably affect HDL functionality.

METHOD

The present review discusses the effects of environmental factors, including obesity, smoking, alcohol consumption, dietary habits, various pharmacologic interventions, as well as aerobic exercise, on HDL functionality.

RESULT

Experimental and clinical studies or pharmacological interventions support the impact of these environmental factors in the modification of HDL functionality, although the mechanisms that are mediated are poorly understood.

CONCLUSION

Further research should be conducted to unreal the underlying mechanisms of these environmental factors and to identify new pharmacologic interventions, capable of enhancing CEC, improving HDL functionality and potentially improving cardiovascular risk.

Dysfunctional High-Density Lipoproteins in Type 2 Diabetes Mellitus: Molecular Mechanisms and Therapeutic Implications

High density lipoproteins (HDLs) are commonly known for their anti-atherogenic properties that include functions such as the promotion of cholesterol efflux and reverse cholesterol transport, as well as antioxidant and anti-inflammatory activities. However, because of some chronic inflammatory diseases, such as type 2 diabetes mellitus (T2DM), significant changes occur in HDLs in terms of both structure and composition. These alterations lead to the loss of HDLs' physiological functions, to transformation into dysfunctional lipoproteins, and to increased risk of cardiovascular disease (CVD). In this review, we describe the main HDL structural/functional alterations observed in T2DM and the molecular mechanisms involved in these T2DM-derived modifications. Finally, the main available therapeutic interventions targeting HDL in diabetes are discussed.

A Novel N-Substituted Valine Derivative with Unique Peroxisome Proliferator-Activated Receptor γ Binding Properties and Biological Activities

A proprietary library of novel N-aryl-substituted amino acid derivatives bearing a hydroxamate head group allowed the identification of compound 3a that possesses weak proadipogenic and peroxisome proliferator-activated receptor γ (PPARγ) activating properties. The systematic optimization of 3a, in order to improve its PPARγ agonist activity, led to the synthesis of compound 7j (N-aryl-substituted valine derivative) that possesses dual PPARγ/PPARα agonistic activity. Structural and kinetic analyses reveal that 7j occupies the typical ligand binding domain of the PPARγ agonists with, however, a unique high-affinity binding mode. Furthermore, 7j is highly effective in preventing cyclin-dependent kinase 5-mediated phosphorylation of PPARγ serine 273. Although less proadipogenic than rosiglitazone, 7j significantly increases adipocyte insulin-stimulated glucose uptake and efficiently promotes white-to-brown adipocyte conversion. In addition, 7j prevents oleic acid-induced lipid accumulation in hepatoma cells. The unique biochemical properties and biological activities of compound 7j suggest that it would be a promising candidate for the development of compounds to reduce insulin resistance, obesity, and nonalcoholic fatty liver disease.

Anti-Inflammatory Effect for Atherosclerosis Progression by Sodium-Glucose Cotransporter 2 (SGLT-2) Inhibitor in a Normoglycemic Rabbit Model

Background and Objectives

We sought to investigate an anti-atherosclerotic and anti-inflammatory effect of sodium-glucose cotransporter-2 (SGLT-2) inhibitors in normoglycemic atherosclerotic rabbit model.

Methods

Male New Zealand white rabbits (n=26) were fed with a 1% high-cholesterol diet for 7 weeks followed by normal diet for 2 weeks. After balloon catheter injury, the rabbits were administered with the Dapagliflozin (1mg/kg/day) or control-medium for 8 weeks (n=13 for each group). All lesions were assessed with angiography, optical coherence tomography (OCT), and histological assessment.

Results

Atheroma burden (38.51±3.16% vs. 21.91±1.22%, p<0.01) and lipid accumulation (18.90±3.63% vs. 10.20±2.03%, p=0.047) was significantly decreased by SGLT-2 inhibitor treatment. The SGLT-2 inhibitor group showed lower macrophage infiltration (20.23±1.89% vs. 12.72±1.95%, p=0.01) as well as tumor necrosis factor (TNF)-α expression (31.17±4.40% vs. 19.47±2.10%, p=0.025). Relative area of inducible nitric oxide synthase⁺ macrophages was tended to be lower in the SGLT-2 inhibitor-treated group (1.00±0.16% vs. 0.71±0.10%, p=0.13), while relative proportion of Arg1⁺ macrophage was markedly increased (1.00±0.27% vs. 2.43±0.64%, p=0.04). As a result, progression of atherosclerosis was markedly attenuated in SGLT-2 inhibitor treated group (OCT area stenosis, 32.13±1.20% vs. 22.77±0.88%, p<0.01). Mechanistically, SGLT-2 treatment mitigated the inflammatory responses in macrophage. Especially, Toll-like receptor 4/nuclear factor-kappa B signaling pathway, and their downstream effectors such as interleukin-6 and TNF-α were markedly suppressed by SGLT-2 inhibitor treatment.

Conclusions

These results together suggest that SGLT-2 inhibitor exerts an anti-atherosclerotic effect through favorable modulation of inflammatory response as well as macrophage characteristics in non-diabetic situation.

Fenofibrate and Dyslipidemia: Still a Place in Therapy?

Dyslipidemia is one of the major cardiovascular risk factors, but beyond statin treatment-which represents the cornerstone of therapy-a relevant practical uncertainty regards the use of fibrate derivatives. In the lack of successful results from the main cardiovascular trials, guidelines recommend the use of peroxisome proliferator-activated receptor agonists in selected cases, i.e. patients with true atherogenic dyslipidemia. However, recent observations indicate that fenofibrate treatment may provide a reliable complementary support against residual cardiovascular risk. We therefore summarize current evidence on fenofibrate, seeking to provide an updated interpretation of recent studies in the field.

Mechanisms of Adiponectin Action: Implication of Adiponectin Receptor Agonism in Diabetic Kidney Disease

Adiponectin, an adipokine secreted by adipocytes, exerts favorable effects in the milieu of diabetes and metabolic syndrome through its anti-inflammatory, antifibrotic, and antioxidant effects. It mediates fatty acid metabolism by inducing AMP-activated protein kinase (AMPK) phosphorylation and increasing peroxisome proliferative-activated receptor (PPAR)-α expression through adiponectin receptor (AdipoR)1 and AdipoR2, respectively, which in turn activate PPAR gamma coactivator 1 alpha (PGC-1α), increase the phosphorylation of acyl CoA oxidase, and upregulate the uncoupling proteins involved in energy consumption. Moreover, adiponectin potently stimulates ceramidase activity associated with its two receptors and enhances ceramide catabolism and the formation of its anti-apoptotic metabolite, sphingosine 1 phosphate (S1P), independently of AMPK. Low circulating adiponectin levels in obese patients with a risk of insulin resistance, type 2 diabetes, and cardiovascular diseases, and increased adiponectin expression in the state of albuminuria suggest a protective and compensatory role for adiponectin in mitigating further renal injury during the development of overt diabetic kidney disease (DKD). We propose AdipoRon, an orally active synthetic adiponectin receptor agonist as a promising drug for restoration of DKD without inducing systemic adverse effects. Its renoprotective role against lipotoxicity and oxidative stress by enhancing the AMPK/PPARα pathway and ceramidase activity through AdipoRs is revealed here.

Fenofibrate modified-release pellets with lag phase and high oral bioavailability

Purpose

Fenofibrate and statin combination therapy is highly recommended by the current clinical guidelines for treatment of mixed dyslipidemia. In this study, an innovative delayed-release preparation of fenofibrate was designed to reduce the risk of muscle toxicity, caused by simultaneous administration of this combination therapy, by altering the pharmacokinetic profile of fenofibrate, as well as to improve the oral bioavailability of the modified-release formulation.

Methods

Micronized fenofibrate was used to prepare drug-loaded cores via a powder layering process before multiparticulate pellet coating. Different coating formulations (Eudragit^® RS PO/E100, Eudragit^® RS PO/RL PO, Eudragit^® NE30D/HPMC, and EC/HPMC) were screened, and their in vitro release was compared with the commercial sustained-release pellets Lipilfen^®. Two optimized formulations were evaluated in beagle dogs using two commercial preparations of fenofibrate (the immediate-release preparation Lipanthyl^® and the sustained-release pellets Lipilfen^®) as references.

Results

The in vivo release of fenofibrate from R1 and R2 selected from in vitro tests exhibited a lag phase, and then rapid and complete drug release. The relative bioavailabilities of R1 and R2 were 100.4% and 201.1%, respectively, which were higher than that of Lipilfen^® (67.2%).

Conclusion

The modified fenofibrate pellets developed showed enhanced bioavailability and delayed-release properties. They have the potential to improve safety and compliance when co-administrated with statins. This is the first report of a delayed-release fenofibrate preparation.

P465L-PPARγ mutation confers partial resistance to the hypolipidaemic action of fibrates

AIMS

Familial partial lipodystrophic syndrome 3 (FPLD3) is associated with mutations in the transcription factor PPARγ. One of these mutations, the P467L, confers a dominant negative effect. We and others have previously investigated the pathophysiology associated with this mutation using a humanized mouse model that recapitulates most of the clinical symptoms observed in patients who have been phenotyped under different experimental conditions. One of the key clinical manifestations observed, both in humans and mouse models, is the ectopic accumulation of fat in the liver. With this study we aim to dissect the molecular mechanisms that contribute to the excessive accumulation of lipids in the liver and characterize the negative effect of this PPARγ mutation on the activity of PPARα in vivo when activated by fibrates.

MATERIAL AND METHODS

P465L-PPAR mutant and wild-type mice were divided into 8 experimental groups, 4 different conditions per genotype. Briefly, mice were fed a chow diet or a high-fat diet (HFD 45% Kcal from fat) for a period of 28 days and treated with WY14643 or vehicle for five days before culling. At the end of the experiment, tissues and plasma were collected. We performed extensive gene expression, fatty acid composition and histological analysis in the livers. The serum collected was used to measure several metabolites and to perform basic lipoprotein profile.

RESULTS

P465L mice showed increased levels of insulin and free fatty acids (FFA) as well as increased liver steatosis. They also exhibit decreased levels of very low density lipoproteins (VLDL) when fed an HFD. We also provide evidence of impaired expression of a number of well-established PPARα target genes in the P465L mutant livers.

CONCLUSION

Our data demonstrate that P465L confers partial resistance to the hypolipidemic action of fibrates. These results show that the fatty liver phenotype observed in P465L mutant mice is not only the consequence of dysfunctional adipose tissue, but also involves defective liver metabolism. All in all, the deleterious effects of P465L-PPARγ mutation may be magnified by their collateral negative effect on PPARα function.

Effect of fibrates on glycemic parameters: A systematic review and meta-analysis of randomized placebo-controlled trials

AIMS

The aim of this meta-analysis of randomized placebo-controlled clinical trials was to assess the effect of fibrates on glycemic parameters.

MATERIALS AND METHODS

Only randomized placebo-controlled trials investigating the impact of fibrate treatment on glucose homeostasis markers were searched in PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases (from inception to April 11, 2017). A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate the impact of potential confounders on glycemic parameters.

RESULTS

This meta-analysis of data from 22 randomized placebo-controlled clinical trials involving a total of 11,402 subjects showed that fibrate therapy significantly decreased fasting plasma glucose (WMD: -0.28 mmol/L, 95% CI: -0.42, -0.14, p < 0.001), insulin levels (WMD: -3.87 pmol/L, 95% CI: -4.97, -2.78, p < 0.001) and insulin resistance (HOMA-IR, WMD: -1.09, 95% CI: -1.71, -0.47, p = 0.001), but with no effect on HbA1c (WMD: 0.01%, 95% CI: -0.18, 0.19, p = 0.955). All analyses were robust in the leave-one-out sensitivity analysis except for insulin levels that showed a non-significant result (WMD: -0.84 pmol/L, 95% CI: -6.36, 4.68, p = 0.766) following omission of one of the included trials.

CONCLUSION

This meta-analysis has shown that fibrate treatment significantly decreases fasting plasma glucose, insulin levels, and HOMA-IR indicating additional clinical therapeutic benefits.

Remnant lipoproteins

PURPOSE OF REVIEW

To review recent advances in the field of remnant lipoproteins and remnant cholesterol with a focus on cardiovascular disease risk.

RECENT FINDINGS

In line with previous years' research, current observational, genetic, and mechanistic studies find remnant lipoproteins (defined in different ways) to be involved in atherosclerosis development and cardiovascular disease risk. High concentrations of remnant cholesterol could explain some of the residual risk of cardiovascular disease seen after LDL cholesterol lowering. This will be increasingly important as populations worldwide become more obese and more have diabetes, both of which elevate remnant cholesterol concentrations. Many smaller scale studies and post hoc analyses show that remnant cholesterol can be lowered by different types of drugs; however, results from large scale studies with the primary aim of reducing cardiovascular disease risk through lowering of remnant cholesterol in individuals with elevated concentrations are still missing, although some are under way.

SUMMARY

Remnant cholesterol is a risk factor for cardiovascular disease, and can be lowered by different types of drugs; however, large scale studies of cardiovascular disease risk reduction through remnant lipoprotein lowering are under way.

The impact of triglycerides on glucose tolerance: Lipotoxicity revisited

Elevated plasma triglycerides (TGs) are early key features of conditions associated with a dysregulation in glucose metabolism and may predict the development of type 2 diabetes (T2D) over time. Although the acute ingestion of lipid, either mixed with or shortly before the meal, is neutral or slightly beneficial on glucose tolerance, a short-term increase in plasma TGs induced by either an i.v. lipid infusion or a high-fat diet produces a deterioration of glucose control. Accordingly, chronic lowering of plasma TGs by fibrates improves glucose homeostasis and may also prevent T2D. The chronic effects of the elevation of dietary lipid intake are less clear, particularly in humans, being the quality of fat probably more important than total fat intake. Although on the bases of the available experimental and clinical evidence it cannot be easily disentangled, with respect to elevated non-esterified fatty acids (NEFA) the relative contribution of elevated TGs to glucose homeostasis disregulation seems to be greater and also more plausible. In conclusion, although the association between elevated plasma TGs and impaired glucose tolerance is commonly considered not causative or merely a consequence of NEFA-mediated lipotoxicity, the available data suggest that TGs per se may directly contribute to disorders of glucose metabolism.

Adiponectin and Its Receptors in Diabetic Kidney Disease: Molecular Mechanisms and Clinical Potential

Diabetic kidney disease (DKD) is a major complication for diabetic patients. Adiponectin is an insulin sensitizer and anti-inflammatory adipokine and is mainly secreted by adipocytes. Two types of adiponectin receptors, AdipoR1 and AdipoR2, have been identified. In both type 1 and type 2 diabetes (T2D) patients with DKD, elevated adiponectin serum levels have been observed, and adiponectin serum level is a prognostic factor of end-stage renal disease. Renal insufficiency and tubular injury possibly play a contributory role in increases in serum and urinary adiponectin levels in diabetic nephropathy by either increasing biodegradation or elimination of adiponectin in the kidneys, or enhancing production of adiponectin in adipose tissue. Increases in adiponectin levels resulted in amelioration of albuminuria, glomerular hypertrophy, and reduction of inflammatory response in kidney tissue. The renoprotection of adiponectin is associated with improvement of the endothelial dysfunction, reduction of oxidative stress, and upregulation of endothelial nitric oxide synthase expression through activation of adenosine 5'-monophosphate-activated protein kinase by AdipoR1 and activation of peroxisome proliferator-activated receptor (PPAR)-α signaling pathway by AdipoR2. Several single nucleotide polymorphisms in the AdipoQ gene, including the promoter, are associated with increased risk of the development of T2D and DKD. Renin-angiotensin-aldosterone system blockers, adiponectin receptor agonists, and PPAR agonists (e.g., tesaglitazar, thiazolidinediones, fenofibrate), which increase plasma adiponectin levels and adiponectin receptors expression, may be potential therapeutic drugs for the treatment of DKD.

Effect of ezetimibe add-on therapy over 52 weeks extension analysis of prospective randomized trial (RESEARCH study) in type 2 diabetes subjects

BACKGROUND

Lowering cholesterol levels decreases the risk of atherosclerotic diseases. Effective ways to stably reduce LDL-C level are warranted in type 2 diabetic patients, a high-risk population for CVD, with various anti-diabetic therapeutic background. The RESEARCH study focuses on LDL-C reduction in this population along with modifications of the lipid profiles. We evaluated long-term ezetimibe add-on therapy in T2DM patients with hypercholesterolemia.

METHODS

In a randomized, multicenter, open-label, prospective study, a total of 109 T2DM patients not attaining LDL-C target value despite first-line dose statin (10 mg of atorvastatin or 1 mg of pitavastatin) therapy in Japan were recruited. We investigated the difference in cholesterol lowering effect between ezetimibe (10 mg) add-on statin (EAT) group and double-dose statin (DST) group. Changes of parameters related to atherosclerotic event risks were assessed.

RESULTS

The reduction of LDL-C was larger in the EAT group (28.3%) than in the DST group (9.2%) at 52 weeks as well as the primary endpoint of 12 weeks. EAT achieved significant lower levels of TC and apo B, respectively. Both treatments attained significant reduction in sd-LDL-C or hsCRP on this long-term basis. Notably, sd-LDL-C in EAT reduced as low as 36.1 ± 14.9 mg/dl to reach near the threshold (35.0 mg/dl) for atherosclerosis with significantly higher achievement rate (55.6%) than DST treatment. Simultaneously, hsCRP reduction by EAT attained as low value as 0.52 ± 0.43 mg/l.

CONCLUSIONS

In the present 52-week long-term period, ezetimibe add-on therapy showed a robust advantage in lowering LDL-C and in attaining target LDL-C values compared with the doubling of statin dose. Moreover, it's meaningful that sd-LDL, powerfully atherogenic lipoprotein, exhibited prominent decrease consistently prominently by ezetimibe add-on therapy. DM patients with hypercholesterolemia are at high risk for CAD, and adding ezetimibe onto usual-dose statin treatment in Japan has been suggested as the first-line therapy for those DM patients who failed to attain the target LDL-C value (UMIN000002593).